Static Var Generator (SVG)


    Static Var Generator (SVG)


    SVG Principle


    The principle of the SVG static var generator is very similar to that of Active Power Filter, as demonstrated in the picture below. When the load is generating inductive or capacitive current, it makes load current lagging or leading the voltage. SVG detects the phase angle difference and generates leading or lagging current into the grid, making the phase angle of current almost the same as that of voltage on the transformer side, which means fundamental power factor is unit.


    Delta’s PQC series SVG is also capable of correcting load imbalance.


    SVG Structure


    Delta PQC Series SVG static var generator is also modular in design, and the Delta SVG system consists of one or several SVG modules and an optional Liquid Crystal Monitor & Control Panel (LCM). Each SVG module is an independent reactive power compensation system, and users can change the SVG rating by adding or removing SVG modules.


    SVG modules and LCM panel can be embedded in Delta’s standard SVG cabinet or in a customized cabinet. There are usually breakers, cable terminals and Surge Protection Device (SPD) in the SVG cabinet.


    Active harmonic filters are more of a system solution. How do they work?


    Harmonics come from the nonlinear load. Active harmonic filter, also called harmonic correction units, is parallel devices that act like a noise cancellation system and inject equal and opposite frequencies to mitigate harmonics. The filters can also provide additional current to correct the power factor. So, what’s left coming from the source flowing back to the utility is only a nice, clean current that is in phase.


    For example, if we run four 6-pulse variable frequency drives at the same time, we have a harmonic spectrum of 5th and 7th and 11th and 13th harmonics. The waveform will show a significant amount of harmonic current in the total harmonic distortion. When the active harmonic filter is turned on, it will inject equal and opposite harmonics to cancel what’s there. The waveform now will be clean and in phase. If we go back and look at the harmonic spectrum, the current distortion is very low. 


    Adding active harmonic filters can be a good harmonic solution for power systems. Though more costly than other options, if you have multiple drives running all the time and multiple drives as backup, harmonic filters would be a reliable way to capture any and all of the harmonics coming from the loads. However, one important thing to know from a system design standpoint is that your drive should have either a DC choke or an AC line reactor to minimize the harmonics coming out of the drives.


    Active harmonic filters typically come in 50, 60, 100, 200 and 300 ampere units that you can parallel. Another benefit to using active harmonic filters is that you cannot overload them, because once they put out the maximum harmonic current and power factor correction that they can, they stop producing at that level—whether it’s 100 or 120 amperes, whatever the case may be.


    Using active harmonic filters on your power system provides a system-level solution for internal and external harmonic protection. 


    What are active harmonic filters?


    Active harmonic filters are parallel filters (which means the current doesn’t go through the filter) that are used to reduce, or mitigate, harmonics to tolerable levels as defined by IEEE-519.  Active filters use a set of transistors and capacitors to filter (or clean) the current wave by injecting inverse currents to cancel out the undesired harmonic components.  Active filters are significantly more expensive than passive filters and take up more space.  Size is an immense factor in system design today and should be accounted for when deciding on what type of harmonic filter is right for you.


    Active filters can work with multiple drives; when the active filter reaches its limit, it won’t overload. In addition, if an active filter breaks, it won’t stop the motor (since current isn’t going through the filter); it just won’t filter the current wave.


    Active harmonic filters can effectively cancel harmonic distortions from the network. This blog post will explain the key criteria that should be kept in mind when buying an active harmonic filter.


    1.1. Inverter topology


    Most modern AHFs are built on 3-level NPC inverter topology which brings several benefits compared to AHFs built on the conventional 2-level topology. In 3-level topology, the switching frequency and voltage stress are distributed among the IGBTs. Reduced stress extends the lifetime of the power electronics. Higher efficiency, lower losses and lower noise levels are also achieved. These make the overall cost of ownership much lower.


    1.2. Losses


    Depending on design and topology, AHFs can have higher or lower losses. Checking the losses is important as they will reduce the life cycle cost of the investment. Usually AHFs have about 2-3% losses (depending on rated power). AHFs built on 3-level NPC inverter topology have lower losses than 2-level ones. Depending on the user profile, reduced losses create a potential for considerable financial savings if the LCC is calculated over a period of few years.


    1.3. Response time


    Some power quality phenomena occur extremely fast, requiring the mitigation to be even faster. If the process is affected by fast voltage fluctuations or transients, it is very important to evaluate the AHF’s overall response time.


    1.4. Interharmonics


    Interharmonics are usually caused by synchronization issues. If the installation includes interharmonic sources, the manufacturer should be consulted as not all AHFs can deal with this. It is a common issue with cycloconverters or some types of older wind turbine generators.


    1.5. Harmonic compensation capacity


    Harmonics can be seen in the odd and even orders. Common capacity for AHFs is 25th or 50th harmonic order. Sometimes there is a claim of being able to mitigate the 51st harmonic, which has little value as harmonic orders of 51st and above do not appear in electric power systems. An important issue is that the AHF can offer the possibility of selecting which harmonic order to compensate. For some devices, it is possible to select the whole harmonic spectrum (1st to 50th, odd and even), but for some others only few harmonic orders can be selected. Depending on the application, the capacity to compensate a certain harmonic order is a critical issue affecting the performance of the whole system.


    1.6. Electromagnetic compatibility (EMC)


    In some countries there are strict guidelines regarding the EMC. To be sure that the AHF is not causing interference it must be fitted with a properly designed EMC filter.


    1.7. Derating according to harmonic order


    The rating of an AHF is usually defined at nominal load (at 50/60Hz). As the AHF works further up the harmonics, its capacity compared to nominal starts to derate. For example, a derating of 50% at the 13th harmonic order means that a 100A AHF has only the capability to compensate 50A at the 13th harmonic order.


    Derating is a matter of how robustly the AHF is designed. This capability is more dependent on the change rate of the current than just the frequency and magnitude of the current (all different frequencies, their magnitude and phase have an effect). Because of this, a derating curve cannot show the capability of the AHF. The only way to verify the real compensating capability of a device is to check its di/dt capacity. This compensating capability is clearly better in 3-level NPC inverter topology AHFs compared to 2-level topology devices.


    1.8. Physical footprint and modularity


    Most suppliers offer several installation alternatives: Cubicle type, wall mount or loose modules that can be locally installed inside new or existing cubicles. A modular AHF design allows customers to adapt to potential changes in future harmonic filtering and reactive power compensation needs. Modular design means that it is possible to add easily to the AHF’s capacity within the existing configuration, saving both costs and space.


    1.9. Voltage


    AHFs are offered in a range of voltages, most common is 200V up to 690V. Some manufacturers can produce AHFs for higher voltages, up to 1000V, without step-up transformer, reducing costs and footprint. It is possible to connect AHFs to high voltage (over 1kV) systems using a suitable step-up transformer. Step-up (or step-down) transformers can reduce compensation performance due to increased impedance between the AHF and network.


    1.10. HMI


    There are different HMI setups for AHFs. Some have a very simple front HMI while others include graphs showing the current and voltage waveforms and many further functions in different languages. A great added value is to have at least a web-based interface allowing in-depth monitoring and control functionality.


    1.11. Commissioning software


    Commissioning and service of AHFs without proper tools can be time consuming. Some suppliers provide software for this. Minimum required functionality should be that the system performs a self-check of voltage and CT phase order, CT polarity check, self-diagnosis and self-calibration. Such features will find installation errors before they can cause problems and will shorten the commissioning time. If the AHF does not have this type of software the commissioning becomes more complex and might require external support adding to the system costs.


    1.12. Smart Grid functionality


    Some AHFs have a built-in power quality analyser to calculate the required compensation. Some suppliers enable the user to connect all AHFs on site through a web-based architecture. An operator can then have an overview of the status of all connected AHFs and log them. This enables the possibility to log events that could have caused production disturbances, monitor individual AHFs, and remote monitoring and analysis capability.


    1.13. Control of detuned capacitor banks


    Very often AHFs are installed at sites together with existing or new contactor or thyristor switched detuned capacitor banks. Some suppliers offer the possibility to control the steps of these banks directly from the AHF’s control system through dedicated digital outputs in the AHF. By doing this it is possible to use the comprehensive power quality monitoring and reporting features of AHFs to accurately monitor all the parameters of the installation and control the total power quality improvement needs. This brings an optimal system integration, efficient operation, cost savings on the control system, and the possibility to build hybrid var compensators (HVC).


    1.14. Cancellation of harmonics in neutral (4W)


    Typically, active harmonic filters are installed to cancel harmonics distortions created by AC and DC drives or UPS systems. However, use of LED lighting as well as other single-phase loads in the buildings also produces tripplen harmonics which accumulate in the neutral wire and should also be mitigated. Therefore, active harmonic filter should be easily configurable to 3W or 4W applications.

How to Maintain Your Dust Collector


    How to Maintain Your Dust Collector


    The inception of the dust collector has allowed companies to effectively capture airborne particulate from an air stream. This has become more important for several reasons. First, containing particulate — toxic or not — is necessary to provide a healthy and clean work environment. Second, increasing local and global awareness of air pollution, containment and the process dust in industrial applications has emphasized the importance of dust collectors. Finally, expanding regulations have pressured companies to properly design, install, operate and maintain dust collection equipment.


    To ensure dust collector bags are functioning properly, you need to perform periodic inspections, as well as repair and replace damaged or malfunctioning equipment. A routine inspection and maintenance program will boost your equipment's performance and life. To maintain the health and effectiveness of your dust collector, follow our helpful list of procedures.


    1. Create an inspection/maintenance program — A typical program consists of a schedule for periodic inspections that are performed on a daily, weekly, monthly, semi-annual and annual basis. Failing to periodically inspect the dust collector can hurt its performance. Subsequently, the dust collector may not meet EPA outlet emissions standards.


    2. Don't exceed recommended pressure drop — Sometimes called differential pressure, it's the amount of static resistance across filters when operating a positive- or negative-pressure dust collector. Pressure drop, typically measured in inches of water column (in w.c.), is a good indicator of the amount of dust that has collected on the filter media and, if continually monitored, the condition of the filters.


    New filters have the lowest pressure drop because of the inherent permeability of the media. As the bags develop a dust cake, some particulate embeds itself into the filter media, increasing pressure drop accordingly. The filtering of the airstream through this accumulated dust cake provides high-efficiency collection of fine particulate. In fact, the highest efficiency a dust collector can offer is just before the cleaning is initiated. However, high differential pressures can cause filter media bleed-through or blinding. Therefore, do not to exceed the manufacturer's recommended operating pressure drop.


    3. Ensure cleaning system functions properly — Equipment use a variety of cleaning systems to dislodge accumulated dust cake from the filter media. Systems include reverse air, shaker or pulse clean. Regardless of the style of cleaning, it is imperative that this system function properly at all times. Without an effective cleaning system, dust will continue to build on the bags. The result will be an increased pressure drop and reduced volume of ventilation air at the pick-up points. Further, airstream velocities within the ductwork will decrease and cause dropout of dust in the ducts. This may choke the entire system and render it ineffective.


    4. Watch for visible emissions — This includes any particulate that can be seen discharging from the exhaust stack. These emissions indicate a breach in a seal or a broken (torn) filter. In either case, you must find and correct the leak immediately. Not only will the emission cause a health concern and damage the property outside the plant, but it may also bring about monetary fines imposed by local, state and federal environmental agencies. Additionally, fans located downstream of the collector can be damaged from abrasion or become imbalanced if you don't correct this condition quickly.


    Continually monitor exhaust from the dust collector. Besides visual inspections, consider incorporating a broken bag detector into the clean air ductwork. If a bag begins to fail, or there's a leak in the bag seal, you'll detect the particles that bypass the media. Typically, these detectors use triboelectric technology. These devices can be wired to an alarm horn, siren or PLC.


    5. Select the right exhaust fan — Dust collection systems require an exhaust fan to accelerate ventilation air from the point of pick-up, through the ductwork and dust collector filter media and out the exhaust stack. Fans are selected to accommodate volume (SCFM) and pressure drop throughout the system. Calculate the pressure drop by evaluating the static resistance of the dust collector, ductwork and pick-up points/hoods.


    6. Inspect the filter media — This is the most important item in a dust collector because it accumulates and supports a dust cake. This dust cake is what provides high filtering efficiencies during operation. Inspect the clean-air side of the dust collector for leaks and the bags for tears. If pressure-drop within a dust collector becomes extremely high relative to historical data, it may be caused by excessive dust cake or blinding of the filter bags.


    Depending on the application, differential pressure may take a number of hours or even days to develop. It is essential that you keep filtering velocities low for new filter media. Reducing the volume decreases the airstream's velocity, thus protecting the bags from high-velocity impingement of dust. If you expose bags to the fan's full volume, fine particles may embed themselves into the bags' inner fibers and begin blinding. This can also reduce the life of the bags by damaging the fibers of the media. So make sure to season a collector's filter bags.


    This is not an all-inclusive list. Each piece of equipment and application is different, and each has its own unique components and features. But these simple procedures can help you monitor and maintain your dust collector's heath, as well as prevent shutdowns due to inefficiencies, prolong filter life and prevent costly EPA fines.


    Dust Filter Bag


    The welding of the filter bag cage is not standardized. The unevenness of the welding frame of the filter bag cage or friction with the cabinet will cause the dust filter bag to be worn out during shaking. Generally, the uneven surface of the filter bag cage refers to burrs or edges at the welding place;


    The dust bag installation is not standard. The dust filter bags are too loose when suspended, which may cause the dust filter bag to collide or friction with other components, resulting in damage to itself;


    The disassembly and assembly of the dust filter bag is not standard. When the dust filter bag is disassembled or installed, it is likely to collide with metal edges and wear the cloth bag. This kind of injury is not easy to detect, but ash will appear during work;


    The cleaning cycle is unreasonable. The dust removal cycle is too short and the dust removal method is wrong, which will increase the burden on the dust filter bag and cause the dust filter bag to be easily damaged;


    Dust-containing gas properties. The temperature of the dusty gas is too high, the concentration is too high, and the wind speed is too high, etc., it will increase the burden of the dust filter bag and easily cause premature damage to the dust filter bag. In addition, if the dust filter bag used fails to match this working condition, it is easy to burn. On the contrary, if the temperature is too low and the wind speed is low, it is easy to cause condensation and dust removal of the dust filter bag. The high dust filter bag needs to be replaced.


    Five Things You Should Know about Dust Collection Filter Media


    #1: Most industrial dust collection manufacturers design filters or collectors. Few design both.


    The customer wins when a manufacturer understands the behavior of both the filter media and the dust collector and designs both. When a supplier can optimize the interaction between the filter media’s performance and the collector’s performance as a single consolidated system, the customer benefits by a more stable and dependable operation and lower operating costs.


    #2: Effective filter media designs may require thousands of computer simulations before initial lab samples are produced or final media grades are released to production.


    Filter media development is very involved and includes the testing of raw materials and properties of filter media blends. Raw material testing and media development labs often evaluate media components using: high-performance liquid chromatography (HPLC), FTIR (Fourier Transform Infrared) Spectroscopy, TD-GC-MS (Thermogravimetric Analyzer - Gas Chromatography - Mass Spectrometry), and SEM (Scanning Electron Microscopy). These tools help ensure the optimal design and materials are being used to appropriately match the application conditions.


    Development of Donaldson media grades includes computer modeling to predict tensile strength, stiffness, permeability, and a variety of other filtration and efficiency levels. This modeling helps ensure a thorough understanding of the potential physical properties of a media recipe before a test recipe is even produced in the lab. When a recipe shows promise, samples are produced in the lab so physical testing can confirm the predicted properties.


    Donaldson considers filter media development one of its core competencies. Even so, with all our background and experience, new media recipes still go through thousands of computer and lab iterations to achieve the optimized characteristics before we begin production of a new media grade.


    #3: There’s more to manufacturing filter media than meets the eye.


    The general process of developing any filter media should begin by identifying the application requirements. Then specifications are determined for not only the finished media grade, but for the final filtration product in which the dust filter media grade will be incorporated (i.e. cartridge, panel, or filter pack).


    Factors to be considered in media recipe formulation include: a cost level which makes sense for the market; minimum efficiency levels needed to achieve acceptable emissions; the type and amount of material being filtered from the fluid stream by the media filter; and the physical environment to which the media will be exposed. Other factors include: pressure, vibration, temperature, humidity, and chemical composition of contaminants.


    Pressure drop, or the resistance necessary to cause fluid flow through the media, is considered critical to media design because this impacts the energy it takes to move fluid through the media and, therefore, the operating cost of the filter developed.


    All of these variables are considered important, and they must be balanced against one another to formulate an optimized media grade for an application. For example, a formulation may use expensive materials and provide high efficiency, yet the very dense filter media might be expensive to operate in the collector because of the high pressure drop of the filter and its replacement costs. A dense filter media design might also compromise the performance of a cleaning system and could result in shorter overall filter life and increased maintenance material and labor costs.


    On the other end of the spectrum, a filter media comprised of low cost materials with low pressure resistance may offer initial benefits. However, if the media does not handle the physical challenges of the operation or becomes quickly plugged, the operational disruption and maintenance downtime and expense make it a poor choice. Optimizing the various performance measures is essential to overall collector performance.


    #4: Some manufacturers offer 300+ grades of filter media from which to choose.


    Some manufacturers are so serious about providing exactly what the customer needs they offer hundreds of choices to the market, each tailored to meet specific challenges and requirements. If an appropriate media does not exist for an application, new media development may be undertaken.


    #5: Evaluating dust collection manufacturers pays off.


    When evaluating dust collection manufacturers, look for one that offers media grades optimized for your application and for the collector in which they will operate. This will help optimize your filter efficiency performance, extend your filter life, and lower your cost of ownership. Choose a company with a strong history of providing expertise and technical support.


    If you’re employed by a global company, consider a global dust collection manufacturer that can provide excellent customer support around the world – including stock inventory of common filters and parts so they are ready to ship when you need them. A company like this will provide you exactly what you need.

TCXO, Temperature Compensated Crystal Oscillator


    TCXO, Temperature Compensated Crystal Oscillator


    As the name indicated a temperature compensated crystal oscillator provides a means of counteracting the frequency change caused by temperature change in a crystal oscillator.


    The letters TCXO stand for Temperature Compensated Xtal Oscillator - Xtal is short from crystal and implies a quartz crystal resonator. The TCXO module is able to provide considerably improved performance over that of a standard crystal oscillator, especially in terms of frequency stability over a temperature range.


    By measuring the temperature and applying a correction voltage to a VCXO, the frequency stability over a temperature range is considerably improved whilst keeping costs low - using an oven controlled crystal oscillator, OCXO would be considerably more costly and much larger in size.


    Often a wide range of TCXOs of varying frequencies, supply voltages and packages is available from many distributors, enabling these electronic components or modules to be used in many general electronic designs, RF circuit designs, etc.


    Temperature performance of crystal oscillator


    Crystal oscillators are able to provide a much better level of performance than that provided by LC resonator circuits. Nevertheless crystal oscillators are still affected by temperature.


    The angle of the cut and other aspects of the quartz crystal have a major impact on the performance.


    As a result special cuts are defined and one known as the AT cut is the most widely used for these and many other quartz crystal RF applications. This gives a good level of performance for RF circuits in terms of suppression of unwanted modes of vibration as well as the frequency range available, and also the temperature stability.


    Despite this, AT cut crystals on their own cannot meet the requirements for many applications and temperature compensation is required if they are to perform satisfactorily over the required range - often 1 - 70°C at elast is needed.


    The effects of temperature are, to a large degree, repeatable and definable. Therefore it is possible to have an electronic design to compensate for this. By adding additional electronic components to the basic oscillator, it is possible to considerably reduce the effects caused by temperature changes: a temperature compensated crystal oscillator, TCXO.


   



    TCXO solution


    A TCXO adjusts the frequency of the oscillator to compensate for the changes that will occur as a result of temperature changes. To achieve this, the main element within a TCXO is a Voltage Controlled Crystal Oscillator, VCXO. This is connected to a circuit that senses the temperature and applies a small correction voltage to the oscillator as shown below.


    INTRODUCTION


    The history of the development in crystal filter technology, from the initial concepts of Cady to the current wide range of products, provides a fascinating chapter in the development of today’s highly complex electronic products. The crystal filter has been a particularly critical element in the development of narrowband communications systems. The desire to send multiple voice messages on a single telephone line resulted in the introduction of carrier telephone systems in 1916. These early systems used LC filters in the 10 to 40 kHz frequency range. However, the bandwidth limitations caused by realizable coil Q’s were quickly recognized. In 1929, W.P. Mason of Bell Laboratories developed methods for incorporating crystals into LC lattice filter networks. This work resulted in the development of a 60 to 108 kHz basic group-band filter set used to frequency multiplex 12 voice channels. This work is described in Mason’s 1934 paper which was the basis for essentially all crystal filter designs generated during the next 20 years. During this period the major application for crystal filters was in carrier telephone equipment. However, in the mid-1950s, newer narrowband radio communications systems were developed both for military and commercial use which required high-frequency, stable, narrow-bandwidth filters. In most cases, crystal filters were the answer for these filtering applications and a new manufacturing industry was formed to supply these needs. Other applications quickly followed in navigation and radar equipment, in new fire-control systems, and missile control systems. This increased level of activity resulted in new filter design procedures and substantial improvement in the quality of high-frequency filter crystals.


    In the 1960s another major technology step occurred with the development of monolithic crystal filters. Through the 1970s and ’80s evolutionary improvements were made with the development of multi-pole monolithic filters and the extension of the high frequency limits through continued process improvements. Significant theoretical work was also accomplished in this period in the area of device modeling. High frequency limits are still being pushed today with blank etching techniques and improved photo-lithography.


    DESIGN EVOLUTION


    Professor Walter Cady, who carried out much of the original development work on quartz crystals, was apparently the first to suggest the use of crystals as filter elements. In his 1922 paper he shows single-mode crystals with divided electrodes which could be used as coupling elements between adjacent circuits. However, in this configuration, only very narrow bandwidths are achievable and the filter would be useful only as a carrier-frequency filter. In 1927 patent disclosures were filed by L. Espenschied of AT&T and C. Hansell of RCA on the use of crystals in a filter structure. The Espenschied patent shows the use of crystals in a ladder filter structure in a variety of configurations. He also shows the use of inductors in series or in shunt with the crystals to widen the filter bandwidth. In Hansell’s patent the use of a bridge circuit is shown using all capacitors or a center-tapped transformer to balance out the crystal shunt capacitance. This is essentially the hybrid-lattice configuration which is commonly used in discrete crystal filters. He also proposed a method for widening the bandwidth by placing several crystals with slightly different frequencies in parallel. The challenge of providing filters with useful bandwidths was apparent from the earliest days and many techniques (usually unsuccessful, including Hansell’s) were attempted. In his patent Hansell makes the interesting observation that “The crystal filter has the advantage of being so sharply selective that the necessity for more than a single section probably will never arise.”


   


    Ceramic Filtration


    Locally manufactured ceramic filters have traditionally been used throughout the world to treat household water. Currently, the most widely implemented ceramic filter is the Potters for Peace design. The filter is flowerpot shaped, holds about 8-10 liters of water, and sits inside a plastic or ceramic receptacle. To use the ceramic filters, families fill the top receptacle or the ceramic filter itself with water, which flows through the ceramic filter or filters into a storage receptacle. The treated water is then accessed via a spigot embedded within the water storage receptacle. The filters are produced locally at ceramics facilities, and then impregnated with colloidal silver to ensure complete removal of bacteria in treated water and to prevent growth of bacteria within the filter itself. Numerous other locally-made and commercial ceramic filters are widely available in developed and developing countries. The filter is flowerpot shaped, holds about 8-10 liters of water, and sits inside a plastic or ceramic receptacle. To use the ceramic filters, families fill the top receptacle or the ceramic filter itself with water, which flows through the ceramic filter or filters into a storage receptacle. The treated water is then accessed via a spigot embedded within the water storage receptacle. The filters are produced locally at ceramics facilities, and then impregnated with colloidal silver to ensure complete removal of bacteria in treated water and to prevent growth of bacteria within the filter itself. Numerous other locally-made and commercial ceramic filters are widely available in developed and developing countries.


    Lab Effectiveness, Field Effectiveness, and Health Impact


    The effectiveness of ceramic filters at removing bacteria, viruses, and protozoa depends on the production quality of the ceramic filter. Most ceramic filters are effective at removing bacteria and the larger protozoans, but not at removing the viruses. Studies have shown adequate removal of bacterial pathogens in water filtered through high quality locally-produced or imported ceramic filters in developing countries. A 60-70% reduction in diarrheal disease incidence has been documented in users of these filters. Studies have also shown significant bacterial contamination when poor-quality locally produced filters are used, or when the receptacle is contaminated at the household level. Because there is no chlorine residual protection, it is important that users be trained to properly care for and maintain the ceramic filter and receptacle.


    What Is a Ceramic Resonator?


    A ceramic resonator is an electric component that exhibits a series resonant and a parallel resonant center frequency. It exhibits a piezoelectric characteristic that makes the ceramic material generate minute electrical energy when subjected to electromechanical expansion and compression. The resulting mechanical energy component produces the electric component and vice versa, and the result is a complex reactance that leads to resonance observed as the characteristic of having a center frequency. Materials such as lead zirconium titanate have a ceramic piezoelectric characteristic.


    Oscillators are electronic circuits that generate periodic waveforms. The ceramic resonator may be used as a frequency reference in the electronic oscillator, wherein the accuracy of the resulting frequency is not as high as in the crystal oscillator. Error in frequency for the ceramic resonator circuit may be as high as 5%, while that for the crystal oscillator is less than 0.1%.


    The ceramic resonator may also be used for intermediate frequency (IF) amplifier stages, which are found in heterodyne radio receivers that derive a common IF to receive a sub-band of frequencies. For instance, a radio receiver tuned to 1,000 kilohertz (kHz) or 1,000 cycles per second may generate a local oscillator frequency of 1,455 kHz so that the difference is 455 kHz, which is a typical IF frequency. To receive a 1,500 kHz signal, the local oscillator is tuned to 1,955 kHz and the resulting difference is still 455 kHz. This ceramic resonator is tuned or cut to resonate at around 455 kHz and will serve a sub-band like 550 to 1,600 kHz as in a typical amplitude modulation (AM) band.


    A typical ceramic resonator has three terminals. The two main terminals are at each wide side of a thin ceramic material, while the middle terminal is usually connected to the thin side and may be grounded or used to tap signal into the rest of the oscillator circuit. There are, however, ceramic resonators as well as crystal resonators with only two terminals.


    Amplifiers are the active parts of the oscillator. The ratio of the output voltage to the input voltage of an amplifier is known as the voltage gain, which is dependent on the frequency of interest. Very few amplifiers will maintain a constant gain over a wide range of frequency. When a ceramic resonator controls the oscillator frequency, the voltage gain at the ceramic resonator frequency has to be greater than 1. If the voltage gain is less than 1, the amplifier will not start oscillating.


    In electronics, design amplifiers and oscillators have very common components. With design shortcomings, some amplifiers can be very close to oscillating. Meanwhile, some oscillators may just stop oscillating and behave like idle amplifiers. Ideally, amplifiers do not have output when there is no input signal.

Benefits of using a humidifier


    Benefits of using a humidifier


   
       
            Humidifier adds moisture to the air, which can benefit people with respiratory symptoms or dry skin.
       
   
   
        There are several ways to use humidifiers in the home or office, but there are also some risks.
   
   
        In this article, learn about the benefits of humidifiers, how to use them correctly, and precautions to take.
   


   
       
            Dryness and humidity
       
   


    By adding moisture to the air, humidifiers may be beneficial for several medical conditions.


    Dry air can cause moisture to evaporate from the skin and respiratory symptoms to worsen over time. Adding moisture to the air with a humidifier can counteract these problems.


    Humidifiers can help people who experience:


    dry skin


    irritated eyes


    dryness in the throat or airways


    allergies


    frequent coughs


    bloody noses


    sinus headaches


    cracked lips


   
        Five humidifier uses and their benefits
   


    Some people experience respiratory symptoms in the summer months, when the weather is hot, and the air contains more allergens. Air conditioners and fans can circulate dry air through the room, and air conditioners remove any moisture from the air. A humidifier may be beneficial during this season.


    However, people are more likely to benefit from a humidifier in the cold months, when cold air dries out the lungs, nose, and lips. Also, some types of central heating can dry out the air indoors.


    Benefits of a humidifier may include:


    1. Preventing influenza


    Authors of one
   
        studyTrusted Source
    noted that humidifiers might reduce the risk of catching the flu. After adding the influenza virus to the air with a simulated cough, researchers found that humidity levels above 40 percent rapidly deactivated virus particles, making them much less likely to be infectious.


    2. Making a cough more productive


    Dry air can cause a person to have a dry, unproductive cough. Adding humidity to the air can get more moisture into the airways, which can make a cough more productive. A productive cough releases trapped or sticky phlegm.


    3. Reducing snoring


    Increasing the amount of moisture in the air can also reduce snoring. If the air is dry, a person’s airways are less likely to be sufficiently lubricated, which can make snoring worse.


    Adding humidity to the air by running a humidifier at night may help to relieve some symptoms.


    4. Keeping the skin and hair moist


    Some people notice that their skin, lips, and hair become dry and fragile in the winter.


    Many types of heating units pump hot, dry air through the house or office, which can make the skin dry, itchy, or flaky. Cold air outside can also dry out the skin.


    Using a humidifier to add moisture to the indoor air may help to reduce the occurrence of dry, cracked skin.


    5. Benefits for the home


    Moisture from a humidifier can be helpful around the home. Any moisture-loving houseplants may become more vibrant, and wood floors or furniture may last longer. Humidity can also help to prevent wallpaper from cracking and static electricity from building up.


    Humid air can also feel warmer than dry air, which could help a person to save money on utility bills in winter months.


   
        Types of humidifiers
   


    While most humidifiers have the same basic function, to add moisture to the air, many types are available:


    Steam vaporizers: These use electricity to create steam, which cools before it leaves the unit. However, there is a risk of burning the skin, and people should avoid using steam vaporizers around children.


    Ultrasonic humidifier: Instead of electricity, these units use vibrations to vaporize water.


    Evaporators: These produce humidity by blowing air past evaporating water.


    Impeller humidifiers: These are generally child-friendly and use rotating disks, rather than heat, to vaporize water.


    Central humidifiers: A person connects one of these units to the central air conditioning in the home or office to add moisture to the entire space.


    Sizes can vary. Console humidifiers are large enough to add moisture to an entire house or office, while personal humidifiers are portable and easy to carry.


    What is an Industrial Humidifier?


    An industrial humidifier is a system that is capable of providing adequate humidity levels in a manufacturing environment. High-speed production processes add to the heat load in a building, bringing down the humidity. This can lead to a dangerous buildup of static electricity in a plant where dust and other flammable materials may be in the air. Processes such as woodworking, printing, and electronic and microchip fabrication, — which involve gluing, coating, and bonding — benefit from humidity control. Energy efficiency is also a consideration with an industrial humidifier.


    Related products include industrial steam humidifiers, as well as electric-powered and gas-fired models. Steam heat exchangers use a heat source for producing steam from tap water or pure water reserves. These are also designed to comply with indoor air quality requirements to ensure proper humidity levels along with clean air for workers.


    Industrial humidifiers are also designed as fog systems that integrate with building automation systems. In this configuration, an industrial humidifier system can be integrated above the factory floor, with the moisture released via fog nozzles. This is a viable alternative to humidifying air traveling through ducts, because excessive heat loads can be managed at the source.


    An industrial humidifier also can be a contamination control system. It can be capable of utilizing adiabatic humidification to control humidity and airborne particles, and reduce the buildup of electrostatic discharge that, when combined with particulates, can be a health hazard and a cause for major industrial accidents. Along with proper treatment of supply water, an industrial humidification system ensures a safe environment in which to work.


    An industrial humidifier can be found in many manufacturing facilities. Plants that make electronic assemblies require humidification, because the air in buildings producing circuit boards and computer equipment must be free of particles. Semiconductor manufacturing is another major application, because integrated circuit printing requires tightly controlled temperatures, along with a relative humidity (RH) of around 35 percent to 45 percent with acceptable tolerances within a range of 1/2 percent to 5 percent RH.


    What Does a Dehumidifier Do?


   
        A dehumidifier is an appliance that takes moisture out of the air in your home.
   
   
        If you or your family members have asthma or allergies, a dehumidifier might help relieve symptoms and make breathing easier.
   
   
        This article will help you decide whether a dehumidifier is a worthwhile investment for your living space.
   


   
       
            Dehumidifier uses and health benefits
       
   
   
        You may remember the water cycle from elementary school science: evaporation, condensation, and precipitation. What you might not realize is that the water cycle is always taking place in the air you’re breathing, even when you’re spending time inside.
   
   
        “Humidity” is a measure of water vapor in the air. Dehumidifiers remove or minimize this water vapor.
   


   
        How a dehumidifier works
   


    A dehumidifier works by drawing warm air currents into its coils via a fan. The warm air contracts as it’s fed through the refrigerated coils of the machine, and condensation is left inside the dehumidifier.


    As this condensation collects, one droplet of water at a time, it falls into a storage tank attached to the dehumidifier. Cooler, drier air is then released back into your home through the other side of the machine.


    Your dehumidifier should be able to bring the moisture in the air down to a relative humidity of 30 to 50 percent. Many dehumidifiers come with a meter that measures the relative humidity where it’s placed in your home, and you can set the humidity to the percentage you desire.


    Application of Dehumidifiers for Various Industries


   
       
            Food Industry:
Excess humidity causes condensation and a broad range of hygiene problems in the product. Be it powdered food, spices, processed meat, snack foods confectionery products or breweries, consistent and controlled moisture conditions are necessary. Using dry air from a Desiccant dehumidifier can help in controlling the moisture content, which leads to perfect coating and longer shelf life of the food products.
       
   
   
       
            Lithium Batteries:
The primary requirement for manufacturing of lithium batteries is a dry room with very low humidity. Lithium is extremely sensitive to moisture; thus, high moisture content leads to a reduction in performance and life of the product. Industrial dehumidifier ensures that the processing areas have the required amount of moisture in the air which is less than 14gms of moisture per kg of dry air.
       
   
   
       
            Pharmaceutical Industry:
During the processing stage, most of the medicines are in powdered form and are highly hygroscopic. Excess of moisture absorption leads to organic corrosion, biochemical reactions and micro-organism growth on the product. Dehumidifiers help in keeping the required humidity parameters for processing, drying, storing and transportation of medicines.
       
   
   
       
            Cold Stores:
To prevent flowers, vegetables, fruits, milk and processed foods from deterioration they are cooled and stored in cold store under low moisture conditions. Since the cold stores experience the frequent movement of products, warm air with moisture from outside could enter the store. This results in ice and frost formation on the walls, floors and ceilings on the cold stores. Air curtain using Dehumidified air at the cold store doors helps in controlling the ingress of moisture laden entering the cold rooms.
       
   
   
       
            Defense Industry:
Military equipment is highly prone to humidity damage when they are stored for long periods. Uncontrolled humidity causes corrosion and malfunctioning of equipment, fungal growth on maps, drawings and bacterial infection on rations. Storage rooms of standard equipment such as trucks, tanks, guns and ammunition require specific humidity levels and controlled temperature. Dehumidifiers help in preventing corrosion on the equipment by keeping humidity levels less than 35%.
       
   
   
       
            Electronic and Semiconductors:
Components used in assembling or processing of semiconductors are hygroscopic and highly sensitive to excess humidity. Excess moisture results in corrosion of PCB, transistor failures, and condensation on integrated circuits. The RH in semiconductor manufacturing area must be 30% at 20oc. Industrial dehumidifiers also help in protecting the vacuum and EPI equipment.
       
   
   
       
            Turbine Industry:
Moisture can corrode turbines, boilers, condensers and many other machines when they are kept for maintenance during the layup process. High humidity causes corrosion and rusting on the equipment leading to their malfunctioning. As the repair and downtime costs of these equipment are very high, moisture control becomes essential. Industrial dehumidifiers help in keeping moisture levels low during the storage of the product; thus, preventing corrosion.
       
   
   
       
            Leather industry:
The Leather is a hygroscopic material; excess moisture leads to the growth of mold and mildew on leather. Without proper humidity control, leather loses its shine, produces the foul smell, loses its strength and starts decomposing. Relative humidity above 40% leads to micro-organism growth that results in decomposition of leather. Dehumidifiers help in providing controlled moisture conditions during the processing of leather products.
       
   


    Ultrasonic Mist Maker


    I needed a simple mist maker/humidifier for a project that I was working on. I found lots of ideas on the internet, but they all lacked in one area or another, so I decided to design one. The following lays out my easy-to-build ultrasonic mist maker. It works fine and is, by far, the easiest ultrasonic mist maker/humidifier that I’ve ever had to get going.


   


    The misty head


    In an ultrasonic mist maker/humidifier (also called an ultrasonic atomizer), a piezo atomizer disc/transducer (ceramic humidifier) works by transposing high-frequency sound waves into mechanical energy that is transferred into a liquid, creating standing waves. As the liquid exits the atomizing surface of the disc, it’s broken into a fine mist of uniform micron-sized droplets, so the key component required for this little project is a particular (20-mm, 113-kHz) ultrasonic atomizer disc/transducer (see below).


    When buying the transducer, make sure that is has a 113-kHz (±3 kHz) resonance frequency — another popular transducer has a 1.65-MHz (±0.05 MHz) resonance frequency, which is not compatible with this project!


   


    Circuit diagram of the transducer driver


    Below is the circuit diagram of the final part of the project — the transducer driver. As shown in the circuit diagram, it’s a tricky oscillator design based on the ubiquitous tiny time chip NE555P (IC1) to generate proper drive pulse train for the atomizer transducer. In the circuit, the 5K multiturn trimpot (RP1) can be used to set the oscillator frequency to 113 kHz (±5 kHz) (TP1). Even though the ultrasonic mist maker device is configured to run on a single 5-Vdc to 12-Vdc input, this transducer driver needs a 20-Vdc to 26-Vdc (V_DRIVE) power supply channel in addition to a 5-V regulated DC supply rail. So a dedicated power supply circuitry will be introduced later to fulfill that crucial requirement.

Are Hoverboards Dangerous?


    Are Hoverboards Dangerous?


    When hoverboards hit the scene in 2015, they were an immediate success. Also known as self-balancing or two-wheeled boards, these toys can be a fun way to get around. However, many parents began to wonder — just how dangerous are hoverboards?


    Shortly after their debut, several manufacturers started selling hoverboard that were not inspected for quality or safety. News reports revealed potential hoverboard dangers — motorized boards spontaneously overheating, catching fire and causing burns. To date, more than 300 of these incidents have been reported to the Consumer Product Safety Commission.


    Newer hoverboards don’t pose the same level of fire risk. If you have an older model, visit the Consumer Product Safety Commission to see if there’s been a recall. All hoverboards should be compliant with the UL 2272 safety standard.


    However, even if your child has one of the newest models, there are still hoverboard dangers to consider. After all, two-wheeled boards can be difficult to balance on, and falls resulting in injuries are not at all uncommon.


    A Look at Hoverboard Injury Statistics


    How often does a fall result in a serious hoverboard injury? Statistics from the American Academy of Pediatrics study show that about 26,854 children visited an emergency department with a hoverboard injury during 2015 and 2016. The average age of an injured child was 11, with boys being slightly more common than girls (52 percent of the children seen were boys).


    Children were most likely to injure their wrists, forearms and heads. The most common injuries were:


    Fractures (40 percent)


    Bruises (17 percent)


    Strains/sprains (13 percent)


    While these hoverboard injury statistics may seem alarming, many other wheeled toys — that have been around much longer — result in trips to the emergency room as well. During the same 2015 to 2016 time period, skateboards caused almost 121,400 injuries.


    How Does a Hoverboard Work?


    Do you ever daydream about the future? What might the world be like in a few decades? Could there be cars without drivers? Trucks that fly? Boats driving on land and water?


    You may already know about self-driving cars and self balancing hoverboard. But what about hoverboards? Picture it: You’re flying down the sidewalk on an object that looks like a skateboard without wheels. You turn a corner, swerve around other people, and get home from school in record time, without ever touching the ground!


    Does this sound like science fiction? Think again! Hoverboards are already a reality. But how do they work?


    The “hoverboards” you may have seen friends riding are actually self-balancing scooters. These scooters don’t hover above the ground. Instead, they use two wheels to get around.


    Okay, so why are they called HOVERboards? People call self-balancing scooters “hoverboards” because of the sensors that help them stay balanced. The board’s sensors find out which way the rider is leaning. They then tell the board’s motor how fast and in what direction to spin. That’s how this “hoverboard” stays balanced!


    Self-balancing scooters rely on a battery pack for power, and each one contains a logic board. You can think of this as the “brain” of the hoverboard. It processes things like the speed of the board and the tilt of its wheels. The logic board also manages settings. For example, hoverboards can be put in beginner mode to limit their maximum speed.


    If you’re not satisfied with a self-balancing scooter, have no fear! Hoverboards with no wheels are coming soon—and they’ll truly float above the ground. Some of these hoverboards may use the science of magnets. They will have hover engines that contain electrically charged magnets, or electromagnets. These use an inductor to create a powerful magnetic field. When the magnetic field is strong enough, the board will float in the air!


    A company called Omni has also created a hoverboard that uses propellers. Their design even holds the Guinness World Record for the farthest flight by hoverboard. It traveled 275.9 meters (905.2 feet). The Omni hoverboard is expected to hit the shelves in late-2021.


    Would you like to travel by hoverboard? Do you see a future of these vehicles zooming through the streets? Or do you imagine even better ways of getting around? Anything is possible!


    What is an all terrain hoverboard?


    These are similar to the original hoverboards in how they work, but they are generally bigger, stronger and more durable. Instead of being a traditional 6.5 inch hoverboard, most have 8.5 or 10 inch wheels. Instead of solid rubber tires (which are only suitable for smooth ground) they have pneumatic tires for travelling safely and smoothly over a variety of terrains including grass, gravel and sand for a more exciting riding experience. This makes them far more versatile and more fun because you can use them almost anywhere. Most all terrain hoverboards even come with builtin bluetooth hoverboard capability AND they’re suitable for kids and adults of all ages!


    Back in 2015 hoverboards hit the market with a bang. These two wheeled self balancing scooters became THE hot product of the year, and although they hit a few blips along the way (inferior quality models with cheap batteries caused some fire problems in the early days), they have only gone from strength to strength since then. In 2016 Underwriter Laboratories introduced the UL 2272 hoverboard certification, so hoverboards are now safer and higher quality than ever. In 2021 technology has advanced to the stage where we now have all terrain hoverboards that can travel over grass, sand, gravel and more (the traditional hoverboards that first came on the market were only suitable for smooth pavement). In this article I’m going to be discussing which is the best off road hoverboard available today.


    Hoverboard? Still in the Future


   
       
            The hoverboard is fiction, the vision of screenwriters who created the film about Marty McFly, a teenager who travels from 1985 to Oct. 21, 2015, and uses a floating skateboard to flee a gang of bullies.
       
       
            The movie had other futuristic items, like flying cars and self-tying shoes, but none touched the imagination as much as the hoverboard. For the last 25 years, garage tinkerers, physics professors and top engineers at Google have been trying to make one.
       
       
            Inside a drab office park here in Northern California, Greg and Jill Henderson are working on the latest effort. On a recent visit the couple allowed a reporter to stand atop a noisy magnetic skateboard that can float above a copper surface.
       
   
   


   
       
            It hovers about an inch above the ground. But when the 190-pound visitor stood atop the 100-pound board, one gentle push was enough to send him spinning across the room over a cushion of air.
       
       
            The Hendersons have poured their life savings into hover technology and are hoping to create new industries based on this science.
       
       
            Dustin Rubio, 39, an electrician who grew up skateboarding and saw “Back to the Future Part II” when he was a teenager, is not thinking quite that big.
       
       
            This year, Mr. Rubio turned “a leaf blower, some plywood, some plastic and duct tape” into a small hovercraft that his daughters used to glide down the driveway at his home in Napa, Calif. “I was like I’m just gonna make something funny and see if it works,” he said.
       
       
            Unfortunately, his invention is not really a new hoverboard. Bob Gale, who wrote the “Back to the Future” trilogy, said that, in his imagination anyway, the hoverboard floats on a magnetic field similar to magnetic levitation trains.Continue reading the main story
       
   
   


   
       
            This has been extremely difficult, mostly because of something called Earnshaw’s theorem, which states, more or less, that repelling magnets are tough to balance. One way is to use a track that would hold the magnetic skateboard in place, but what self-respecting skateboarder wants to be constrained to a track?
       
       
            Superconductors can also levitate things. In 2011, a research group directed by Alain Sacuto, a physics professor at the Université Paris Diderot, used smoking-cold superconductors to levitate a liquid-nitrogen-filled skateboard that he and others rode across a five-meter magnetic rail.
       
       
            In March, the website Funny or Die released a video that seemed to show the skateboarder Tony Hawk on a real hoverboard. Mr. Hawk later apologized for misleading fans.
       
       
            “As early as this morning I had three emails from people: Is this real? Can I buy it?” Rachel Goldenberg, who produced the video, said on Monday.
       
       
            If you had to time-travel back to 1989 and place a couple of bets on who might invent the hoverboard, Rich DeVaul would have been a good wager. Mr. DeVaul is a senior engineer at Google X, the company’s research division. He is also a longboard skater and a snowboarder.

Steel Pipes
Steel pipes are the most commonly used pipes in water supply systems. They are also used in pipelines for natural gas, and sewerage systems. Although comparatively expensive to other pipes, they hold the advantage of being able to withstand high pressures and are available in more convenient lengths, and can also be welded easily, thereby resulting in lower installation and transportation costs. These types of pipes are highly efficient and can be used in small diameters as needed and are 100% recyclable compared to other materials. The pipes can further be melted down and turned into other usable material in industry. Furthermore, the high strength of these pipes and resistance to damage caused by human errors, tree roots, and extreme weather conditions make these pipes the ideal choice for most water and sewerage supply systems.

The disadvantages of steel pipes include thermal conductivity, which is very poor as there is a difference in heat transfer. These types of pipes are usually bonded with aluminum or copper alloy to increase thermal conductivity and improve heat transfer. Cost is another issue, as these pipes are expensive and this is guided by the misconception of being a one-time purchase. However, steel pipes are difficult to fabricate and lack the malleable qualities that other materials have, therefore repairs and replacements of steel pipes are extra difficult.

Basic material properties

Steel is strong, rigid, and has a low coefficient of thermal expansion. It is also heavy (multiple workers may be needed to transport it) and is subject to corrosion. Sometimes it is called carbon steel or black special steel to differentiate from stainless and galvanized steel. All steel, by definition, contains carbon.

Steel often is used for closed hydronic systems because it is inexpensive, especially when compared with other materials in systems with high pressures, and corrosion is relatively easily controlled in these systems. It also is a good choice for steam and steam-condensate systems because it handles high temperatures and pressures well, and corrosion is normally not an issue in steam pipes. However, corrosion is an issue in steam-condensate pipes, and many engineers specify schedule 80 steel pipe simply because it takes about twice as long to rust through as schedule 40 pipe.

If amines (commonly cyclohexylamine, morpholine, or diethylethanolamine (DEAE) are fed properly to neutralize condensate pipe pH, condensate pipes can last the life of the building. Some building owners do not want these chemicals in steam that may be used for humidification because of health concerns; however, not using these amines might require a change to stainless steel (SS) piping or adding a separate “clean steam” system for humidification and for sterilization of medical instruments.

Rigidity is important because it determines the distance between hangers. Steel pipe is manufactured in 21-ft lengths, and the hangers can be spaced that widely for large-diameter pipe. More flexible materials, however, may require hangers on as close as 4-ft centers or even continuously. Consult ANSI/MSS SP-58: Pipe Hangers and Supports – Materials, Design, Manufacture, Selection, Application, and Installation for details about hangers and hanger spacing.

A low coefficient of thermal expansion minimizes the need for expansion loops and expansion joints. However, the high rigidity of steel means that although it expands less, it exerts very high forces on anchors.

Galvanized steel pipe is steel pipe that is dipped into a pool of zinc (see Figure 1). Galvanizing has two methods of corrosion reduction:

It coats the surface like paint, and under most circumstances it forms a very adherent oxide layer like aluminum and SS.
It provides a sacrificial anode (zinc) to receive corrosion instead of the steel corroding.
Galvanized steel pipe has all the advantages of steel pipe, and is used in insulated and coated piping, plus improved corrosion resistance in most environments, although at a slightly higher cost. Galvanizing works almost perfectly in applications where it is wetted and dried periodically (e.g., road signs and guard rails). It can fail in environments with high sodium (e.g., softened water that started out very hard) because the sodium makes the adherent oxide film detach and react more like steel pipe where the oxide flakes off. If galvanized pipe is being welded, the welder needs to be careful to grind down to the raw steel. Repairing galvanizing on the inside of the pipe is difficult or impossible. If the interior needs a continuous galvanized layer, consider mechanical couplings. (More information is available via the American Galvanizers Association.)

Copper pipe often is used in both hydronic and domestic applications, especially for 2-in. and smaller pipe sizes. However, some contractors propose replacing galvanized steel domestic-water pipe with copper up to 6-in. in size, especially in the Midwest. Copper is an expensive material but has the advantage of weighing less than steel and may require fewer employees to install, depending on weight and union restrictions. Also, copper is generally more noble and corrosion-resistant than steel or galvanized steel pipe fittings.

Stainless steel is widely considered to be resistant to all corrosion. This is true in many circumstances, but not all. Anaerobic and chloride corrosion can affect SS. The most common alloy is 304 SS, which adds 18% chromium and 8% nickel to steel. 304L has reduced carbon content to minimize the tendency for SS to corrode at welds. SS with the L designation is recommended for all SS that will be welded and might have corrosion issues, like fume exhaust and some pipe systems. 316 and 316L add molybdenum to reduce susceptibility to chlorides.

In the past decade, we have seen thinner SS being proposed as an alternative to galvanized seamless steel tube and pipe and larger-diameter copper pipe, primarily for domestic potable-water piping. There is one potential problem with this if done incorrectly (see, “Mixing materials may equal trouble”).

SS requires some oxygen to build an adhering oxide layer, like aluminum car wheels. This is normally not a problem in hydronic heating/cooling systems or domestic-water systems, but a large chilled-water-storage system could have oxygen levels become low enough to have issues with microbially influenced corrosion (known as MIC).

There are many grades of SS. In general, 300 series alloys are the most corrosion-resistant and are nonmagnetic. 400 series are harder, more resistant to abrasion, withstand higher temperatures, and are magnetic. 200 series alloys are used in sinks and applications where less corrosion resistance is acceptable.

What Is A Centrifugal Fan? – Complete Guide


    What Is A Centrifugal Fan? – Complete Guide


    A centrifugal fan is one of the most efficient fans on the market today. Most people think of a centrifugal fan as just a fan; its intricacies are not exactly common knowledge.


    This complete guide will tell you everything you need to know about centrifugal fans. You might be wondering ‘What is a centrifugal fan? What are centrifugal fans used for? What are the different types of fans?


    We will answer these questions and more. We’ll also highlight several useful videos from HVAC experts who break down these concepts in great detail.


    A centrifugal fan or centrifugal blower is a pump or motor that moves air. It pulls the air inside the blower and then pushes it out at a 90o angle. The two main components of a centrifugal fan are the motor and the impeller. An impeller sucks or pulls air, in contrast to a propeller which pushes air.


    Some fans can pull and push air at lower than a 90o angle; these fans are called mixed flow fans.


    Centrifugal fans can either have no exterior housing or structure to offer protection or they can be built with some protective housing.


    As shown in the video below, there are five different types of centrifugal fans, which differ based on the type and shape of the fan blades.


    Backward curved blades


    Backward inclined blades


    Backward inclined aerofoil blades


    Radial blades


    Forward curved blades


    Know the Working of an Axial Fan


    Across industries, there are various machines and devices both electrical and electronic, which are designed for 24/7 working. As a result, they heat up, and if this exceeds the limits set, the device may be damaged which will result in halted production. To avoid machine failure due to excess heat, AC or DC industrial fans are used. There are various types of fans such as centrifugal, axial, and so on. An axial fan is a type of industrial fan which helps cooling of machines and devices. They facilitate parallel air flow to the rotor shaft, which offers ventilation to the device and prevents overheating. This post discusses the working and uses of AC and DC axial fans.


    How Does an Axial Fan Work?


    The industrial fan is chosen based on the direction of the air flow. an axial fan comprises a rotator shaft, blades, impeller, and a housing mostly made of steel. There is an air inlet through which the air enters inside once the rotator shaft rotates. The air flows parallel to the rotor shaft in a linear manner. This increases the flow rate and can gush in and out huge volumes of air. This can be achieved keeping both the pressure and power consumption low. The air enters the impeller in an axial direction. To raise the flow rate, the blades push the impeller and further deflect the flow of air into the guide vane. The air flow from the guide vane again becomes axial and enters the diffuser tube. The kinetic energy of the moving blades is converted into pressure which facilitates the required amount of ventilation. The blades of the axial fan are fixed but can be adjusted in terms of spacing and angle which helps achieve the required flow rate.


    The shape of the blades to some extent also affects the speed of air flow. In axial fans, these blades may be tilted forward, backward, or could be curved. The number of blades may vary from 2 to 20, and the power or motor capacity required to drive operate these fans depends on the number of blades, speed and volume of air flow, and other application requirements. These fans produce pressure difference and force to facilitate the flow of air through them. Depending on the power supply and the application size, you could choose either a DC axial fan or AC axial fan.


    Why high pressure fans are often used in pig barns


    Various ventilation techniques are used  to raise the air quality in pig barns to a desired level. Many of these techniques use a specific type of fan to facilitate the required air movement. A frequently used fan in pig barns is the High Pressure Fan. In this article, we will tell you more about High Pressure Fans and why these fans are often used in pig barns.


    Fundamentally, High Pressure Fans are used in:


    High resistance systems


    Systems in which the fans must have sufficient negative pressure or positive pressure build-up at lower power and speed


    1. Overcoming high resistance


    In most pig barns, each section has its own ventilation system, which provides minimum and maximum ventilation. With a standard ventilation system, the resistance ? P Stat to be overcome in the barn can be around 40 Pa and rise to at least 80 Pa (depending on the system). For such systems, we use a standard range of Axial Fans. Examples of this type of fan are Panel Fans and Tube Mounting Fans. There are, however, systems where, among others, air washers, heat exchangers and air filters cause the negative pressure or positive pressure (? P Stat) to be overcome to rise well above 80 Pa. For these applications, we use High Pressure Fans.


    2. Stable negative pressure when regulating fan speed


    As the conditions inside and outside a barn change daily, a ventilation system must be flexible. In addition, growing pigs are also a changing factor. This means that the amount of air must be variable. It is important to dissipate heat, moisture and ammonia, but primarily to supply oxygen. One of the characteristics of High Pressure Fans is that even when the fan speed is adjusted, they still provide an acceptable pressure build-up. As previously explained in our blog, The fan laws, we see that when regulating the fan speed, the flow (M3/h) is linear and the pressure ? P Stat (Pa) decreases quadratically while the power consumption (Watt) even decreases to the 3rd power.


   



    Industrial centrifugal fan plays an important part in cement production line, especially with the development of preheater pre decomposition kiln, even more important. At the same time the fan is also more power consumption of cement equipment, according to statistics, the total power of about 15% of the total installed capacity of cement plant.


    What is the role of fan in the cement production line?


    High temperature fan: the equipment through the raw material and clinker, Inlet temperature can reach 320℃, is to pre-heater vacuum pumping, the raw material in the preheater down the process of full preheating (material to go down, hot air to go up), while the tower pull over the wind to the raw material mill for Heat, so its shutdown will directly lead to raw material grinding system and firing system shutdown.


    Cement plant kiln exhaust fan: to make high-temperature fan and vertical mill system exhaust out of the dust after the row to the atmosphere.


    Kiln centrifugal blower: it is similar to cement plant kiln exhaust fan, high energy saving,less power.


    Dust collector fan: fan is the main equipment in dust removal systems, offer the power source of the whole systems, and overcome the resistance loss caused by the air flow in the system.


   



    A suction axial flow fan is a type of industrial fan used to cool machines and equipment which heat up after use. Axial flow fans are the type of compressor, which produces airflow parallel to the axis, thus the name. These fans are equipped with impellers, which suck the air in and discharge in the same direction of the axis.


    There are AC as well as DC axial flow fans. It may be designed in different ways such as with a duct or a mounting ring, and so on, depending upon the requirement. So, there are different standard designs which can be customized based on your device and installation type. The materials and accessories used for the fan are decided on these and other physical factors such as the environment it would be exposed to, temperature, moisture, pressure, and so on. This post discusses various designs of axial flow fans, and general features.


    Components of Axial Flow Fan


    The most basic part of an axial flow fan is the motor. Other than that it has ball bearings, blades, and impellers. The fan has a housing or an enclosure which protects it from external damage, spillage, shock, vibration, and so on. The enclosure is metallic and made of steel, aluminum, or alloys. The impellers are usually made of cast aluminum with black paint, thermoplastic, or steel, and designed to be corrosion resistant. The thermoplastic impellers are generally not considered ideal for commercial applications, so they are usually reserved for residential applications. The propellers feature blades. There can be 2 to 20 blades on the propellers.  The fan is connected to a motor drive, which is usually placed in a housing parallel to the direction of airflow. The blades are usually made of aluminum. These fans are designed to be resistant to extreme temperatures, flames, shock, corrosive materials, and so on. A few common accessories of this fan include suitable connecting points, silencer, protection grill, counter flange, vibration controller, feet for the required positioning, and a variable inlet vane.


    Design of Axial Flow Fans


    As mentioned, the fan has various standard designs. Here are a few pointers:


    The fans may be duct mountable or wall mountable.


    Ducted fans have a duct through for a seamless airflow.


    The ring mountable fans allow the airflow from one big enough area to another; so, it is suitable for large spaces.


    The circulator fan has rotating impellers, which are typically used in ceiling fans.


    Axial flow fans offer large airflow rates at low pressures because of their working principle. The blades of these fans draw air parallel to its axis and move it in the forward in the same direction within the axis of the fan.


    How Does an Axial Flow Fan Works?


    Axial fans work similar to an aircraft wing, which possesses an airfoil shape and produce lift. Due to the airfoil shape of the wing, the air above and below it are divided and have different air velocities. This is because the air in above section travels farther than air in the bottom section. The air above has a high air velocity, which produces a high dynamic force and low static pressure. Against this, the air in the below section has low air velocity and produces a high static pressure. These pressure differences create the lift. Now coming to the axial fan, the blades of the propellers act like wings and they push air forward, thereby causing a lift. As a result of this lift, the air is propelled, as well as pushed back. The speed of air continues to increase up to a point even after the air leaves the fan. The airflow is great at the exit than at the entry point.

Painting your electric & gas meter box


    Painting your electric & gas meter box


    Is your electric or gas meter box looking a little worse for wear? Or perhaps you would like the look of your meter box to better fit with your house exterior or cladding? Whether you have a gas meter box, an electric meter box or even a water meter box door that you would like to spruce up, painting your meter box could be the solution for you. Continue reading to find out why and how to paint utility boxes…


    Painting gas meter box


    If you’ve come across this article, it’s likely that you have asked “can you paint a gas meter box?”. The answer is certainly yes! Here at RepairMyMeterBox, our gas meter boxes come in both metal and plastic. Our range of plastic gas meter box covers are made from a high-impact engineering-grade thermoplastic polymer material, making them extremely durable in extreme weather. Not only this, but they are an ideal material to paint over.


    However, your current gas meter box may not be the same. It may be corroded, weathered or simply doesn’t match well with the exterior of your home. Luckily, painting a gas meter box can help to bring it back to life!


    Painting electric meter box


    What about your electrical box? Can it be painted in the same way you can paint a gas meter box? Absolutely. Like our plastic gas meter boxes, our plastic electric boxes are made from a durable thermoplastic polymer material. This makes them resistant to corrosion, and suitable for all kinds of weather conditions. Once again, this type of material is ideal for paint spraying. But which meter box paint is best for the job?


    What paint should I use to paint utility boxes?


    When painting a gas box or electric meter box, we would recommend opting for a durable paint that will help to withstand weather conditions. Please also take special care not to paint over any vents, particularly on gas meter boxes. Using the right meter box paint is important to get a long-lasting and high quality finish.


    Preparation is key


    With any project, preparation is key. This is no different when it comes to painting your meter box. If your meter box cover is plastic, we’d recommend undercoating the surface with a plastic primer. On the other hand, if you’re working with metal meter box, we’d recommend removing any existing gas meter paint, and sanding the metal surface well. This will ensure you get a clean application that is primed to last as long as possible.


    How to hide gas meter in front of the house


    Whether you want to hide the gas meter in front of your house, or simply disguise a gas meter box at your property, painting your gas meter box is a quick, easy and cost-effective solution. You’ll be surprised at how effective a lick of paint can be at helping your meter box blend into the cladding of the house.


    Could it be time to repair or replace your meter box cover?


    Before starting to paint a gas meter box, or sprucing up your electric meter box cover, it’s important to ask yourself whether a coat of paint will fix the problem. If your meter box door is rusty or weather damaged, painting it will only very temporarily solve the problem. You could even be leaving your meter box unprotected.


    Here at RepairMyMeterBox, we offer cost-effective and convenient solutions for repairing your meter box cover. Whether you need a new meter box door, you’re looking for repair kits & parts or you would like a new plastic overbox (suitable for damaged gas or electricity meter boxes); we can help with that. If you are unsure what the best option is for you, get in touch with our team and we’ll be more than happy to guide you in the right direction.


    How to Size a Junction Box


    Electricity powers the devices that make the modern world run, from refrigerators to TVs to industrial machinery. But getting that electricity correctly set up and distributed within homes and businesses requires a lot of special equipment. That equipment includes conduits, raceways and the devices that we’ll discuss in this article: junction boxes.


    When an electrician creates splits and branches in wiring connections that run through cable raceways and conduits, they enclose the connection points within a junction box. A junction box provides protection for these sensitive connections against bad weather, accidental contact, tampering and other hazards that can damage wiring.


    Below, we’ll talk about how to size a junction box appropriately and determine which attributes your junction box needs to have. Before we dive in, we’ll discuss some of the basics everyone should know about what a junction box is and how one works.


    What Is a Junction Box?


    A junction box is an electrical enclosure that protects electrical conductors at the points where they are spliced, tapped and pulled. These enclosures allow electricians to easily access the conductors to perform work when needed while simultaneously keeping the conductors safe from damage and unauthorized access.


    Sometimes, you’ll hear the term “junction box” used to refer to an electrical fixture box. In the true technical definition of a junction box, wires should connect only to other wires and raceways. However, in practice, the term is also frequently used to refer to many other electrical box types in which wires connect to a fixture such as a ceiling fan, light switch or wall socket.


    For more information on the various applications and designs of junction boxes, make sure to see our complete guide to junction box types.


    Types of Feeder Pillars


    Feeder pillar panels can come as custom manufactured or standard empty enclosures. Here are the most common electrical feeder pillars that are available:


    Rail Feeder Pillars


    Rail feeder pillars are non-conductive and are available in an outdoor location or station installments. It eliminates the risk of touch voltages in electrified rail areas. These pillars can have PADS approved Network Rail equipment such as:


    Switchgear


    DC Immune RCD


    DNO Service Hands


    Isolation Transformers


    CT Chamber & Member


    Cut-Outs & Isolators


    LV Feeder Pillars


    Low voltage feeder pillars (LV feeder pillars) are feeder pillar panels that operate at a “Low Voltage” (LV), where “Low Voltage” is defined by the International Electrotechnical Commission (IEC) as a supply system voltage in the range 50 to 1000 V AC or 120 to 1500 V DC (if you’re unsure of your operating voltage, you can easily check this with a good multimeter).


    Electrical distribution pillars give LV power connections for single units or complex developments in the commercial and residential sectors.


    LV feeder pillar is used for utility substation, M&E building services, hazardous area industries, and renewable energy. Highway pillars are used for CCTV, traffic signals, street lighting power, motorway communications, and control and distribution.


    What is an SMC junction box?


    SMC Junction Box is made from sheet moulding compound which ensure excellent dielectric properties.


    These are available in two forms, one with inbuilt terminals and the other in plain format where the provision is there for attaching external terminal plate separately


    While it is true that the junction box presents a neater means of concealing electrical junctions, the real value of the box is providing a degree of protection for the wiring interface at various junction points. It provides facility to connect two or more different size of cable.


    Polycarbonate Enclosures Vs. Fiberglass Enclosures


    The benefits of purchasing a polycarbonate enclosure instead of fiberglass can be found in the strength of the enclosure, its durability, and its modification possibilities. Polycarbonate enclosures can withstand over 900 pounds of impact, which is more than four times the impact resistance of fiberglass enclosures.


    UV Light Resistance


    When fiberglass enclosures are exposed to UV light, their color fades and the fibers are then exposed to direct UV rays which cause the material to “bloom” and deteriorate. In contrast, polycarbonate enclosures are manufactured as a solid piece using injection molding. Polycarbonate is a strong, durable material that withstands the harsh conditions of the outdoors and ultimately lasts longer than fiberglass enclosures. It is also used in car windshields and headlights, because unlike fiberglass, this highly durable plastic maintains its shape, color, and strength even when exposed to direct light.


    Polycarbonate More Easily Modified than Fiberglass


    One of the major differences between polycarbonate and fiberglass enclosures is their modifiability, which includes cutting holes or changing the material in some way. When modified, fiberglass enclosures give off a very fine dust that is irritant to the skin, can be dangerous to inhale, and is so fine it is hard to clean up. Instead of creating a fine dust, polycarbonate enclosures produce small curls of material that can be easily swept away and are not dangerous to touch or inhale. Because fiberglass is made up of interwoven fibers, the material is also more likely to splinter while modifying. Polycarbonate enclosures can be easily modified in the field using standard tools without being damaged or causing health concerns.


    NEMA Rating


    All Integra polycarbonate enclosures are NEMA 4X rated, which means that these enclosures are watertight and can withstand direct water spray. Integra also has a special IP66 rated series that can be submersed in water without deterioration. Even more specifically, polycarbonate enclosures can be marine-friendly, which means that they are salt water resistant.


    Appearance Features


    Polycarbonate enclosures also have a cleaner look than fiberglass, especially when exposed to time and the elements. Integra offers custom color and design options for polycarbonate enclosures to match your application and company branding. These enclosures are molded using colored plastic so the pigment shows all the way through and won’t scratch off or fade like painted fiberglass enclosures. Integra also offers clear lids and even clear enclosures which cannot be accomplished using fiberglass.

What You Need To Know About Wine Additives


    What You Need To Know About Wine Additives


    Did you know that there are a lot of wine additives used to make wine?


    Most wine additives are safe, however, there have been a few notoriously famous cases of unsafe wine additives in the past. Let’s get into the nitty gritty truth about wine additives and dispel some common wine additive myths.


    Worst Case Scenario: A Wine Scandal!


    In 1985, German wine quality control scientists discovered the presence of a commercial solvent, diethylene glycol, in some of their low-end wines. Diethylene glycol is a sweet-tasting toxic chemical sometimes used in anti-freeze. After the scientists discovered the chemical, they soon realized that the German producers were illegally blending Austrian wines with theirs.


    While there were no reported casualties and the wines were pulled from the market, the media scare caused a long-term fear in consumers over wine additives.


    Don’t worry, wine additives are now more closely regulated and the national electronic archives maintains a list of chemicals that are legally allowed for use in wine.



   



    Common Wine Additives


    Food products such as beer, juice and wine are unstable. Because of their volatile nature, processes have been developed to stabilize food products such as homogenizing juice. In the wine world there are many different wine additives, some of which have been used for hundreds of years with no ill effects.


    The intention of these additives is not to adulterate the wine, but to stabilize it. Wines have the potential to last longer when they are stable. Many of these aren’t really additives at all, instead they glom (with molecular attraction) onto unwanted particles and are removed from the finished wine.



    1. Sulfur


    Sulfite sensitivity affects about 1% of the population. Wine usually has about 150 ppm of sulfur added whereas dried fruit has 1000 ppm.


    Sulfites are used to kill unwanted bacteria and yeasts in the winemaking process. Since 1987, American producers have been required to mention the presence of sulfur if it exceeds 10 parts per million (ppm) in the finished wine. The EU recently passed a similar labeling law in 2005.


    The laws are designed to help protect the small percentage of people who are sensitive to sulfur and should not be confused with the myth that sulfites in wine can give you a wine headache.


    2. Yeast


    Yeast is a eukaryotic microorganism that turns sugar into alcohol. Different kinds of yeast greatly affect the flavor of the resulting wine. Some winemakers prefer ambient yeast that is present on their winery equipment while other winemakers create a custom cocktail of cultured yeasts. Each method has unique benefits depending on the wine variety.


    Vitamins! Yeast benefits from vitamins, minerals or any chemical compound that helps keep the yeast alive in grape juice during fermentation. For instance, Thiamine Hydrochloride is a B Vitamin which helps keep yeast happy in high alcohol wines over 14% ABV.


    3. Tannin


    Tannin is one of the 4 traits that makes wines age-worthy. Wine grapes are full of seeds which are very tannic. The seeds are crushed with the grapes to add structure to wine. Oak aging also adds small amounts of tannin as the wine is exposed to the oak wood.


    Oak Chips Are More Sustainable It’s widely accepted in Europe to use oak chips and tannin powder in wine. While oak chips are not as romantic as a room full of oak barrels, they are better for forests and are cheaper to transport.


    4. Sugar


    Chaptalization is the process of adding sugar to grape juice in order to increase the final alcohol level in the finished wine. Adding sugar doesn’t make a wine sweeter because the sugar is consumed by the yeast when it is fermented into alcohol. Chaptalization can add up to 3% ABV to a wine. It is legal in areas where grapes struggle with ripeness, such as Bordeaux, France and Oregon.
Illegal in Some Areas! Adding cane sugar is not legal in California, Argentina, Australia, Southern France and South Africa. Producers can add sugar rich grape concentrate to simulate the same results, as the use of grape concentrate is not considered chaptalization.


    5. Fining & Clarification


    After a wine has been freshly fermented it goes through a period of stabilization. The chemicals added during this process are designed to pull unwanted characteristics out of the wine. For instance, copper sulfate is added to remove free sulfur in a wine. The copper has the same effect as putting a penny in wine to remove undesirable smells. Afterwards the copper sulfate is removed from the wine.


    Why Are There Non-Vegetarian Wine Additives?


    For many hundreds of years in Italy and France, winemakers would add an egg white or two to a large barrel of wine. The proteins in the egg white would bind to free proteins suspended in the wine. After a short wait, the egg white and free proteins would precipitate out of the wine and drop to the bottom of the barrel. Winemakers would strain the clear wine off the top and leave the sludge. This process is called Fining and Racking. Nowadays, there are more advanced ways of achieving the same results including numerous microbial products (read: totally vegetarian!) that perform the same function.


    COVID-19 Impact on the Electronic wet chemicals Market


    The global wet electronic chemicals market includes major Tier I and II suppliers like Avantor Inc, BASF SE, Cabot Microelectronics, Honeywell, and Kanto Chemical Co. Inc. These suppliers have their manufacturing facilities spread across various countries across Asia Pacific, Europe, North America, South America, and Middle East & Africa. COVID-19 has impacted their businesses as well.


    These players have announced the suspension of production due to the lowered demand, supply chain bottlenecks, and to protect the safety of their employees in the US, France, Germany, Italy, and Spain during the COVID-19 pandemic. As a result, the demand for electronic wet chemical sis expected to decline in 2020. Manufacturers are likely to adjust production to prevent bottlenecks and plan production according to demand from tier 1 manufacturers.


    Electronic Wet Chemicals: Market Dynamics:


    Driver: Technological advancements in the electronics industry


    Market penetration of electronic wet chemicals has risen in the electronics and semiconductor industries. They are increasingly used in modern technology industries such as new energy, modern communications, computers, information network technology, microcomputer mechanical intelligence systems, industrial automation, and home appliances.


    Electronic wet chemicals are ultra-pure nature due to which they are extensively used in cleaning and etching application during semiconductor production and processing. The recent commercialization of nano-based devices has boosted the market potential for photoresist and etching chemicals with various technological advancements. Also increase in the use of semiconductors and integrated chips in manufacturing of electrical components gives rise to the electronic wet chemicals market in the estimated period. Therefore, rise in the demand for building electrical components due to various technological advancement in the electronics industry is predicted to be the major driving factor for the electronic wet chemicals market in the estimated period.


    Introduction


    Like other industries, the pulp and paper industry (referred to in the rest of this paper as ''the industry&quot has come under increasing scrutiny for its potential environmental impacts. More than many other industries, however, this industry plays an important role in sustainable development because its chief raw material—wood fiber—is renewable. The industry provides an example of how a resource can be managed to provide a sustained supply to meet society's current and future needs. Pulp and paper additives also plays an important role in this industry.


    This paper looks at the U.S. industry's current experience and practices in terms of environmental stewardship, regulatory and nonregulatory forces, life cycles of its processes and products, and corporate culture and organization. It describes near-term expectations in these areas and examines opportunities for overcoming barriers to improvement. It also provides an industry perspective on the most significant environmental issues of historical and future importance. Although the emphasis here is on complexity, shortcomings, and barriers, the industry has, in fact, continually improved its environmental performance while increasing its business. The problem areas are given more emphasis to highlight some of the challenges to be addressed.


    The global metal surface treatment chemicals market is expected to reach an estimated $5,211.3 million by 2024 with a CAGR of 3.9% from 2018 to 2024.


    The future of the metal surface treatment chemicals market looks promising with opportunities in the automotive, electrical and electronics, construction, packaging, and aerospace markets. The major growth drivers for this market are growing automotive production and increasing residential and commercial infrastructure.


    Emerging trends, which have a direct impact on the dynamics of the metal surface treatment chemicals industry, include replacement of phosphate conversion coatings with zirconium-based conversion coatings, and multiplex surface treatment.

The report forecasts that conversion coatings will remain the largest chemical type and it is expected to witness the highest growth over the forecast period due to its improved corrosion resistance, wear resistance, adhesion, aesthetic appearance, and lubricative properties.

Within the metal surface treatment chemicals market, automotive will remain the largest application driven by increasing automotive production and need for corrosion protection chemicals. The report predicts that the construction application is expected to witness the highest growth over the forecast period supported by growth in the residential and commercial infrastructure.

Asia-Pacific is expected to remain the largest region and witness the highest growth over the forecast period due to growth of construction sector and rapid industrialization in developing countries.


    Some of the metal surface treatment chemicals companies profiled in this report include PPG Industries, Henkel AG & Company, KGaA, Platform Specialty Products Corporation, Quaker Chemical Corporation, Nippon Paint Holdings Co, and others.


    Scope


    Market size estimates: Global metal surface treatment chemical market size estimation in terms of value ($M) and volume (M Lbs.) shipment.


    Trend and forecast analysis: Market trend (2013-2018) and forecast (2019-2024) by end use and use industry.


    Segmentation analysis: Global metal surface treatment chemical market size by type of application, chemical, and product form in terms of value and volume shipment.


    Regional analysis: Global metal surface treatment chemical market breakdown by key regions such as North America, Europe, and Asia & Rest of World.


    Growth opportunities: Analysis on growth opportunities in different applications and regions of metal surface treatment chemical in the global metal surface treatment chemical market.


    Strategic analysis: This includes M&A, new product development, and competitive landscape of metal surface treatment chemical in the global metal surface treatment chemical market. Analysis of competitive intensity of the industry based on Porter's Five Forces model.

What you need to know about boompole usage and best practices


    What you need to know about boompole usage and best practices


    In an earlier blog post, we established that one of the golden rules of audio recording is achieving a good signal-to-noise ratio, and that one of the best methods for doing this is to position the microphone as close to the sound source as possible.


    Camera-mounted microphones may be great for busy run-and-gun situations, but when critical dialogue is involved, they just simply cannot get close enough for a lot of applications.


    This is where boompoles come into play.


   
        Though a number of factors may influence the limitations on mic placement potential, the overall preferred method is to boom from above, or below if absolutely necessary.
   


    Best boom positioning


    Booms are a commonly used piece of sound equipment that allow you to position the mic close to your subject while staying just out of shot. Though a number of factors may influence the limitations on mic placement potential (for example, the chosen camera frame and the overall design of the set), the overall preferred method is to boom from above, or below if absolutely necessary. You should never record from the sides.


    Holding the boom pole above shot ensures that the optimum pickup area of the mic is directed towards the subject's mouth, and then towards the ground - which we assume won't be generating much noise. This will give you natural-sounding dialogue, which is well-isolated from the ambience of the surroundings. In addition, the boom and mic will both be well out of the actor's way, leaving them free to roam the scene and not feel distracted by the sight of it.


    If you absolutely must boom from below, ensure you switch off any noisy air conditioners or fans that will almost certainly be picked up by your microphones in an indoor setting. When listening back, you may find dialogue more bass-heavy after being captured from beneath. This is to be expected from alternate mic positions, so be prepared for a little extra work in post production to match the tone of your other dialogue to this take.


    As for booming from the sides, this is not standard practice. There will naturally be a lot of ambient noise in a horizontal plane, which will sit in line with your actors and mic in this placement situation. This noise will definitely make its way into your recording, ruining your ideal signal-to-noise ratio.


    Boom-holding techniques


    Manufacturers such as ourselves understand that nobody wants to support a heavy object above their head all day long. This is why booms are generally constructed out of aluminium or carbon fibre, to keep weight minimised. The R?DE Boompole, Mini Boompole and Micro Boompole are made of the former material, while the R?DE Boompole Pro and Micro Boompole Pro are designed with the latter.


    You'll find it much easier to support weight that is close to your body, rather than further away. For this reason, it is best to keep your arms close to your head, and hold them straight up. Use your front arm as the main pivot point and lock your elbow to support the majority of the boom's weight. Try to position your hand as close to the centre of the pole length as possible, to give you a better centre of gravity (though this may not be possible if the pole is fully extended).


    As for your rear arm, you can use it to steer or angle the boompole as required. Grip it firmly, but not tightly, and be sure not to tap or rub it, as this will transfer unwanted sound to the mic.


    If possible, hold your boom parallel to the floor and high above your head, using both arms at a similar, comfortable height. This will ensure it does not enter the corner of the camera's frame, which it could do if you were to hold the pole at a steep angle.


    Of course, you don't want the tip of the mic to fall into shot either, so pay attention to any fatigue that might cause you to slowly lower it.


    One great way to manage your mic height is to have visual cues marked in your head as to where the edge of frame actually is. Ask the director of camera operator to work out your lowest possible mic position prior to filming a take. Once established, take a mental note by using objects in the background as your guide. These could be the top of a building in the background, a window frame nearby or anything else you can easily see.


    Proper cable management


    You will also need to run an audio cable from the mic, down the length of the boom and finally to your digital audio recorder. This cable is important, and needs to be both neat and tidy - not just for aesthetic reasons, either. Good cable management will reduce any possible handling noise caused by it tapping against the boompole, and won't hinder your movements by becoming tangled.


    Some booms allow you to run your cable internally through the pole, and some are even sold with pre-installed cables already inside them. These 'cabled' boompoles feature a coiled audio cable with XLR connectors at each end, perfect for quick connections to your mic and further cables to then run to your audio recording device.


    A major advantage of cabled booms is the faster, easier setup time - great for high-pressure gigs such as news gathering, where you may need to react quickly to a live situation. Disadvantages, however, include a higher overall weight through the pole, no choice of audio cable type to use (you are stuck with what it comes with) and the possibility that the cable may rattle, causing unwanted handling noise.


    Even before OSHA created 29 CFR 1910.269 Appendix D, “Methods of Inspecting and Testing Wood Poles,” it seems likely that pole inspection was a rule of thumb for many field employees. After all, they set poles and repeatedly climbed them to handle upgrades, maintenance, wood rot and decay.


    Today, given OSHA regulations and the fact that pole testing and inspections are not difficult to perform, it would also seem likely that workers would adhere to these practices. Unfortunately, some employees don’t inspect a pole at all before climbing. Others believe they can easily comply with regulations by merely rapping a pole several times with a hammer prior to ascending. They have been incorrectly taught by other climbers that it’s sufficient to rap a pole and listen for a hollow sound.


    In the last few years, there have been several tragic events due to rotten wood poles falling or otherwise collapsing. The root cause of these events was failure to properly inspect and test the poles prior to climbing or changing tension. It is a disturbing reality to know that skilled and qualified climbers like us would forgo a basic safety procedure such as this one.


    Remember that poles should be inspected not only prior to climbing, but also when working out of a manlift device or while using a digger derrick boom. If tension must be changed, consider how it will affect the pole and if the pole will be able to handle the change in tension.


    Special attention also should be paid to pole inspection and testing during developmental training. Take advantage of this time to teach employees proper, safe work procedures. Additionally, make them aware of any special circumstances due to a pole’s location. For example, utility workers in Florida must deal with poles set in swamp water. In the Midwest and northern areas of the U.S., poles are planted in frozen ground for several months each year.


    Following is the text of 1910.269 Appendix D for use during your next tailgate. While covering this information with your crews, think about your company’s guidance document regarding pole inspection and testing. Does it meet OSHA’s minimum requirements? If not, this may be a good time to meet with the author of the guidance document to discuss necessary changes.


    OSHA 1910.269 Appendix D: Methods of Inspecting and Testing Wood Poles
I. Introduction
When work is to be performed on a wood pole, it is important to determine the condition of the pole before it is climbed. The weight of the employee, the weight of equipment being installed, and other working stresses (such as the removal or retensioning of conductors) can lead to the failure of a defective pole or one that is not designed to handle the additional stresses. (1) For these reasons, it is essential that an inspection and test of the condition of a wood pole be performed before it is climbed.


    Footnote (1): A properly guyed pole in good condition should, at a minimum, be able to handle the weight of an employee climbing it.


    If the pole is found to be unsafe to climb or to work from, it must be secured so that it does not fail while an employee is on it. The cleaning pole can be secured by a line truck boom, by ropes or guys, or by lashing a new pole alongside it. If a new one is lashed alongside the defective pole, work should be performed from the new one.


    II. Inspection of Wood Poles
Wood poles should be inspected by a qualified employee for the following conditions: (2)


    Footnote (2): The presence of any of these conditions is an indication that the pole may not be safe to climb or to work from. The employee performing the inspection must be qualified to make a determination as to whether or not it is safe to perform the work without taking additional precautions.


    A. General Condition
The pole should be inspected for buckling at the ground line and for an unusual angle with respect to the ground. Buckling and odd angles may indicate that the pole has rotted or is broken.


    B. Cracks
The pole should be inspected for cracks. Horizontal cracks perpendicular to the grain of the wood may weaken the rescue pole. Vertical ones, although not considered to be a sign of a defective pole, can pose a hazard to the climber, and the employee should keep his or her gaffs away from them while climbing.


    C. Holes
Hollow spots and woodpecker holes can reduce the strength of a wood pole.


    D. Shell Rot and Decay
Rotting and decay are cutout hazards and are possible indications of the age and internal condition of the pole.


    E. Knots
One large knot or several smaller ones at the same height on the pole may be evidence of a weak point on the pole.


    F. Depth of Setting
Evidence of the existence of a former ground line substantially above the existing ground level may be an indication that the pole is no longer buried to a sufficient extent.


    G. Soil Conditions
Soft, wet or loose soil may not support any changes of stress on the camera pole.


    H. Burn Marks
Burning from transformer failures or conductor faults could damage the pole so that it cannot withstand mechanical stress changes.