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Thursday, March 31, 2011

Preventive Maintenance Strategies for Compressed Air Systems

A brewery neglected to perform routine maintenance on its compressed air system for years. As a result, two of its centrifugal compressors, whose impellers had been rubbing against their shrouds, were unable to deliver the volume of air they were rated for and one of those units had burned up several motors during its lifetime. In addition, plant personnel did not inspect the system’s condensate traps regularly. These traps were of a type that clogged easily, which prevented the removal of moisture and affected product quality. Also, the condensate drains were set to operate under the highest humidity conditions, so they would actuate frequently, which increased the system’s air demand. As a result, energy use was excessively high, equipment repair and replacement costs were incurred unnecessarily, and product quality suffered. All of this could have been avoided through regular maintenance.

Like all electro-mechanical equipment, industrial compressed air systems require periodic maintenance to operate at peak efficiency and minimize unscheduled downtime. Inadequate maintenance can increase energy consumption via lower compression efficiency, air leakage, or pressure variability. It also can lead to high operating temperatures, poor moisture control, excessive contamination, and unsafe working environments. Most issues are minor and can be corrected with simple adjustments, cleaning, part replacement, or elimination of adverse conditions. Compressed air system maintenance is similar to that performed on cars; filters and fluids are replaced, cooling water is inspected, belts are adjusted, and leaks are identified and repaired.

A good example of excess costs from inadequate maintenance can be seen with pipeline filter elements. Dirty filters increase pressure drop, which decreases the efficiency of a compressor. For example, a compressed air system that is served by a 100-horsepower (hp) compressor operating continuously at a cost of $0.08/kilowatt-hour (kWh) has annual energy costs of $63,232. With a dirty coalescing filter (not changed at regular intervals), the pressure drop across the filter could increase to as much as 6 pounds per square inch (psi), vs. 2 psi when clean, resulting in a need for increased system pressure. The pressure drop of 4 psi above the normal drop of 2 psi accounts for 2% of the system’s annual compressed air energy costs, or $1,265 per year. A pressure differential gauge is recommended to monitor the condition of compressor inlet filters. A rule of thumb is that a pressure drop of 2 psi will reduce the capacity by 1%.

All components in a compressed air system should be maintained in accordance with the manufacturers’ specifications. Manufacturers provide inspection, maintenance, and service schedules that should be strictly followed. Because the manufacturer-specified intervals are intended primarily to protect the equipment rather than optimize system efficiency, in many cases, it is advisable to perform maintenance on compressed air equipment more frequently.

One way to tell if a compressed air system is well maintained and operating efficiently is to periodically baseline its power consumption, pressure, airfl ow, and temperature. If power use for a given pressure and flow rate increases, the system’s efficiency is declining. Baselining the system will also indicate whether the compressor is operating at full capacity, and if that capacity is decreasing over time. On new systems, specifications should be recorded when the system is fi rst installed and is operating properly.

Types of Maintenance

Maintaining an air compressor system requires caring for the equipment, paying attention to changes and trends, and responding promptly to maintain operating reliability and effi ciency. To assure the maximum performance and service life of your compressor, a routine maintenance schedule should be developed. Time frames may need to be shortened in harsher environments. Proper maintenance requires daily, weekly, monthly, quarterly, semi-annual, and annual procedures. Please refer to the Compressed Air System Best Practices Manual for the types of procedures that are relevant to the compressors and components in your system. Excellent maintenance is the key to good reliability of a compressed air system; reduced energy costs are an important and measurable by-product. The benefi ts of good maintenance far outweigh the costs and efforts involved. Good maintenance can save time, reduce operating costs, and improve plant manufacturing efficiency and product quality.

Source: http://www1.eere.energy.gov/industry/bestpractices/pdfs/compressed_air6.pdf

Tuesday, March 29, 2011

Maintaining System Air Quality

"Maintaining the proper air quality level is essential for keeping compressed air energy costs down and to ensure reliable production."

Poor air quality can have a negative effect on production equipment and can increase energy consumption and maintenance needs. The quality of air produced should be guided by the quality required by the end-use equipment. The air quality level is a function of the levels of particulate, moisture, and lubricant contaminants that the end uses can tolerate. Such air quality levels should be determined before deciding whether the air needs additional treatment. Compressed air should be treated appropriately but not more than is required for the end-use application. The higher the quality, the more the air usually costs to produce (in terms of initial capital investment in equipment, energy consumption and maintenance).

Once the true end-use air quality requirements have been determined, the proper air treatment equipment can be configured. Separators, filters, dryers and condensate drains are used to improve compressed air quality. Treatment equipment maintenance is critically important for sustaining the desired air quality levels.

Grouping Equipment with Similar Air Quality Requirements
One strategy to improve air quality is to group end uses having similar air quality requirements in reasonably close proximity and install the appropriate air treatment equipment to serve these end uses with a minimum of distribution piping. Some-times, grouping similar requirements of best quality air together is not always practical; if the requirement for this class is sufficiently high (70% or more of total), consider supplying the entire plant with this air quality level. If practical, separation of groups of end uses requiring similar pressure and air quality also allows some compressors and air treatment equipment to be located close to the end uses.

Filtration
Through proper filtration, appropriate air quality levels can be achieved. Because some end uses may require a higher level of air quality than others, it may not be necessary to have the entire airflow filtered to the highest level of air quality. Filters cause pressure drop that increases as the elements become fouled. Filters should be rated for the maximum anticipated operating pressure, but should be sized for the maximum anticipated rate of flow at the anticipated minimum operating pressure. The three types of compressed air filters (particulate, coalescing, and adsorption) have different functions and must be selected for the appropriate application.

Dryers
Compressed air dryers can be very effective at removing condensate from compressed air. Dryers are of three types: deliquescent, refrigerated, and desiccant. Deliquescent dryers provide a Pressure Dew Point (PDP) of 20°F lower than the dew point of the air entering them. Refrigerated dryers provide a PDP of between 35°F and 38°F and desiccant dryers can provide a PDP as low as -100°F. Dryers should be sized for the maximum anticipated rate of fl ow and must be matched to the air quality requirements. Overdrying wastes energy.

Separators
Moisture separators and condensate traps are used to remove condensate from the air stream. Because the fi rst step in condensate removal is to separate it from the air stream, moisture separators should follow each intercooler and aftercooler.

Condensate Traps
There are four main types of condensate drains: manual, level-operated mechanical (fl oat) traps, electrically-operated solenoid valves and zero-loss traps with reservoirs. Traps should allow removal of condensate, but not compressed air, and should not be left open.

Source: http://www1.eere.energy.gov/industry/bestpractices/pdfs/compressed_air12.pdf

Monday, March 28, 2011

Engineer End Uses for Maximum Efficiency

Compressed air is one of the most important utility requirements of many industrial manufacturing plants because it directly serves processes and applications such as pneumatic tools, pneumatic controls, compressed air operated cylinders for machine actuation, product cleansing and blow-off applications. Ensuring an appropriate, stable pressure level at the end-use applications is critical to the performance of any industrial compressed air system. End uses that are engineered for maximum efficiency can help provide the consistent supply of compressed air that ensures reliable production.

To ensure the efficiency of compressed air end-use applications, a number of steps should be taken:
  1. Review the pressure level requirements of the end-use applications. Those pressure level requirements should determine the system pressure level. Because there is often a substantial difference in air consumption and pressure levels required by similar tools available from different manufacturers, request exact figures from each manufacturer for the specific application. Do not confuse maximum allowable with required pressure.
  2. Monitor the air pressure at the inlet to the tool. Improperly-sized hoses, fittings and quick disconnects often result in large pressure drops. These drops require higher system pressures to compensate, thus wasting energy. Reduced inlet pressure at the tool reduces the output from the tool and, in some cases, may require a larger tool for the specified speed and torque.
  3. Avoid the operation of any air tool at “free speed” with no load. Operating a tool this way will consume more air than a tool that has the load applied.
  4. Check the useful life of each end-use application. A worn tool will often require higher pressure, consume excess compressed air, and can affect other operations in the immediate area.
  5. Air tools should be lubricated as specified by the manufacturer, and the air going to all end uses should be free of condensate to maximize tool life and effectiveness.
  6. End uses having similar air requirements of pressure and air quality may be grouped in reason-ably close proximity, allowing a minimum of distribution piping, air treatment, and controls.
  7. Investigate and, if possible, reduce the highest point-of-use pressure requirements. Then, adjust the system pressure.
  8. Investigate and replace inefficient end uses such as open blowing with efficient ones such as vortex nozzles.
Case Study: A New Compressed Air Application is Configured for Maximum Efficiency
A large, custom printing company installed a more technologically-advanced printing machine that could increase the output of its existing units. However, the initial configuration of the new printing machine more than doubled the compressed air demand of the entire site. After a thorough review, the plant personnel realized that it would be more cost-effective for the new machines to be redesigned to consume less air at lower pressures than to increase compressor capacity at all of the company’s printing plants. Once the printing machines were reconfigured, the total air demand per printing machine was reduced from 27 standard cubic feet per minute (scfm) to 4.5 scfm and the need for 100 pounds per square inch gauge (psig) compressed air was eliminated, resulting in substantial avoided costs in energy and capital expenditures.

Source: http://www1.eere.energy.gov/industry/bestpractices/pdfs/compressed_air10.pdf

Friday, March 25, 2011

Eliminate Inappropriate Uses of Compressed Air

Compressed air generation is one of the most expensive utilities in an industrial facility. When used wisely, compressed air can provide a safe and reliable source of power to key industrial processes. Users should always consider other cost-effective forms of power to accomplish the required tasks and eliminate unproductive demands. Inappropriate uses of compressed air include any application that can be done more effectively or more efficiently by a method other than compressed air. The table below provides some uses of compressed air that may be inappropriate and suggests alternative ways to perform these tasks.

Potentially Inappropriate Uses could be replaced by following suggested alternatives:
  • Clean-up, Drying, Process cooling: Low-pressure blowers, electric fans, brooms, nozzles
  • Sparging: Low-pressure blowers and mixers
  • Aspirating, Atomizing: Low-pressure blowers
  • Padding: Low to medium-pressure blowers
  • Vacuum generator: Dedicated vacuum pump or central vacuum system
  • Personnel cooling: Electric fans
  • Open-tube, compressed air-operated vortex coolers without thermostats: Air-to-air heat exchanger or air conditioner, add thermostats to vortex cooler
  • Air motor-driven mixer: Electric motor-driven mixer
  • Air-operated diaphragm pumps: Proper regulator and speed control; electric pump
  • Idle equipment (Equipment that is temporarily not in use during the production cycle.): Put an air-stop valve at the compressed air inlet
  • Abandoned equipment (Equipment that is no longer in use either due to a process change or malfunction.): Disconnect air supply to equipment
Example
The table below shows inappropriate uses of compressed air in an automobile assembly plant. The plant took several action steps identified in the table to eliminate or reduce these inappropriate uses. Peak flow is identified in cubic feet per minute (cfm).


The plant audit showed that the energy used to generate the compressed air averages 18 kW/100 cfm. The aggregate electric rate at the plant is $0.05 per kWh.

Annual savings = [kW per cfm] x [cfm savings] x [# of hours] x [$ per kWh]


= 18/100 x [(150 x 6,500) + (1,000 x 5,000) + (800 x 3,500)
+ (750 x 3,500)] x $0.05
= $102,600

Net savings:
Calculate electric energy costs for the motor-driven vacuum pump, fans, and actuators, and subtract these costs from the annual savings calculated to determine the net savings. Note that there will be a one-time cost of installation for the added equipment.

Source: http://www1.eere.energy.gov/industry/bestpractices/pdfs/compressed_air2.pdf

Wednesday, March 23, 2011

Effect of Intake Air on Compressor Performance

The effect of intake air on compressor performance should not be underestimated. Intake air that is contaminated or hot can impair compressor performance and result in excess energy and maintenance costs. If moisture, dust, or other contaminants are present in the intake air, such contaminants can build up on the internal components of the compressor, such as valves, impellers, rotors, and vanes. Such build-up can cause premature wear and reduce compressor capacity.

"When inlet air is cooler, it is also denser. As a result, mass flow and pressure capability increase with decreasing intake air temperatures, particularly in centrifugal compressors."

This mass flow increase effect is less pronounced for lubricant-injected, rotary-screw compressors because the incoming air mixes with the higher temperature lubricant. Conversely, as the temperature of intake air increases, the air density decreases and mass flow and pressure capability decrease. The resulting reduction in capacity is often addressed by operating additional compressors, thus increasing energy consumption.

To prevent adverse effects from intake air quality, it is important to ensure that the location of the entry to the inlet pipe is as free as possible from ambient contami-nants, such as rain, dirt, and discharge from a cooling tower. If the air is drawn from a remote location, the inlet pipe size should be increased in accordance with the manufacturer’s recommendation to prevent pressure drop and reduction of mass flow. All intake air should be adequately filtered. A pressure gauge indicating pressure drop in inches of water is essential to maintain optimum compressor performance.

When an intake air filter is located at the compressor, the ambient temperature should be kept to a minimum, to prevent reduction in mass flow. This can be accomplished by locating the inlet pipe outside the room or building. When the intake air filter is located outside the building, and particularly on a roof, ambient considerations are important, but may be less important than accessibility for maintenance in inclement or winter conditions.

How to Select an Intake Air Filter
A compressor intake air filter should be installed in, or have air brought to it from a clean, cool location. The compressor manufacturer normally supplies, or recom-mends, a specific grade of intake filter designed to protect the compressor. The better the filtration at the compressor inlet, the lower the maintenance at the compressor. However, the pressure drop across the intake air filter should be kept to a minimum (by size and by maintenance) to prevent a throttling effect and a reduction in compressor capacity. A pressure differential gauge is one of the best tools to monitor the condition of the inlet filter. The pressure drop across a new inlet filter should not exceed 3 pounds per square inch (psi).

Inlet Filter Replacement
As a compressor intake air filter becomes dirty, the pressure drop across it increases, reducing the pressure at the air end inlet and increasing the compression ratios. The cost of this loss of air can be much greater than the cost of a replacement inlet fi lter, even over a short period of time. For a 200 horsepower (hp) compressor operating two shifts, 5 days a week (4,160 hours per year) with a $0.05/kilowatt hour (kWh)
electricity rate, a dirty intake filter can decrease compressor efficiency by 1%–3%, which can translate into higher compressed air energy costs of between $327 and $980 per year.

Source: http://www1.eere.energy.gov/industry/bestpractices/pdfs/compressed_air14.pdf

Monday, March 21, 2011

Determining the Right Air Quality for Your Compressed Air System

Knowing the proper air quality level required for successful production is an important factor in containing compressed air energy and other operating costs, because higher quality air is more expensive to produce. Higher quality air requires additional air treatment equipment, which increases capital costs as well as energy consumption and maintenance needs. The quality of air produced should be guided by the degree of dryness and filtration needed and by the minimum acceptable contaminant level to the end uses.

Level of Air Quality: Plant Air
Applications: Air tools, general plant air

Level of Air Quality: Instrument Air
Applications: Laboratories, paint spraying, powder coating, climate control

Level of Air Quality: Process Air
Applications: Food and pharmaceutical process air, electronics

Level of Air Quality: Breathing Air 
Applications: Hospital air systems, diving tank refill stations, respirators for cleaning and/or grit blasting

Compressed Air Contaminants
Compressed air contaminants can be in the form of solids, liquids, or vapors. Contaminants can enter a compressed air system at the compressor intake, or can be introduced into the air stream by the system itself.

Air quality class is determined by the maximum particle size, pressure dewpoint, and maximum oil content allowed. For more information, see ISO 8573-1 Compressed Air Quality Classes in the Compressed Air System Best Practices Manual. (See references in sidebar).

One of the main factors in determining air quality is whether lubricant-free air is required. Lubricant-free air can be produced either by using lubricant-free compressors, or with lubricant-injected compressors and additional air treatment equipment. The following factors can help one decide whether lubricant-free or lubricant-injected air is appropriate:
  • If only one end use requires lubricant-free air, only the air supply to it should be treated to obtain the necessary air quality. Alternatively, it may be supplied by its own lubricant-free compressor. If the end uses in a plant require different levels of air quality, it may be advisable to divide the plant into different sections so that air treatment equipment that produces higher quality air is dedicated to the end uses that require the higher level of compressed air purification.
  • Lubricant-free rotary screw and reciprocating compressors usually have higher initial costs, lower efficiency, and higher maintenance costs than lubricant-injected compressors. However, the additional separation, filtration, and drying equipment required by lubricant-injected compressors will generally cause some reduction in system efficiency, particularly if the system is not properly maintained.
Careful consideration should be given to the specifi c end use for the lubricant-free air, including the risks and costs associated with product contamination before selecting a lubricant-free or lubricant-injected compressor. Centrifugal compressors also offer an alternative for plants whose end uses require lubricant-free air.

Source: http://www1.eere.energy.gov/industry/bestpractices/pdfs/compressed_air5.pdf

Friday, March 18, 2011

Determine the Cost of Compressed Air for Your Plant

Most industrial facilities need some form of compressed air, whether for running a simple air tool or for more complicated tasks such as the operation of pneumatic controls. A recent survey by the U.S. Department of Energy showed that for a typical industrial facility, approximately 10% of the electricity consumed is for generating compressed air. For some facilities, compressed air generation may account for 30% or more of the electricity consumed. Compressed air is an on-site generated utility. Very often, the cost of generation is not known; however, some companies use a value of 18-30 cents per 1,000 cubic feet of air.

Compressed air is one of the most expensive sources of energy in a plant. The over-all efficiency of a typical compressed air system can be as low as 10%-15%. For example, to operate a 1-horsepower (hp) air motor at 100 pounds per square inchgauge (psig), approximately 7-8 hp of electrical power is supplied to the air compressor. To calculate the cost of compressed air in your facility, use the formula shown below:

Where:
bhp: Motor full-load horsepower (frequently higher than the motor nameplate horsepower—check equipment specification)
0.746: conversion between hp and kW
Percent time: percentage of time running at this operating level
Percent full-load bhp: bhp as percentage of full-load bhp at this operating level
Motor efficiency: motor efficiency at this operating level

Example
A typical manufacturing facility has a 200-hp compressor (which requires 215 bhp) that operates for 6800 hours annually. It is fully loaded 85% of the time (motor efficiency = .95) and unloaded the rest of the time (25% full-load bhp and motor efficiency = .90). The aggregate electric rate is $0.05/kWh.

Cost when fully loaded =


Cost when fully unloaded =



Annual energy cost = $48,792 + $2,272 = $51,064

Typical Lifetime Compressed Air Costs in Perspective—Costs Over 10 Years
Assumptions in this example include a 75-hp compressor operated two shifts a day, 5 days a week at an aggregate electric rate of $0.05/kWh over 10 years of equipment life.

Source: http://www1.eere.energy.gov/industry/bestpractices/pdfs/compressed_air1.pdf

Wednesday, March 16, 2011

Compressed Air System Control Strategies

Improving and maintaining compressed air system performance requires not only addressing individual components, but also analyzing both the supply and demand sides of the system and how they interact, especially during periods of peak demand. This practice is often referred to as taking a systems approach because the focus is shifted away from components to total system performance.

Matching Supply with Demand
With compressed air systems, system dynamics (changes in demand over time) are especially important. Using controls, storage, and demand management to effectively design a system that meets peak requirements but also operates efficiently at part-load is key to a high performance compressed air system. In many systems, compressor controls are not coordinated to meet the demand requirements, which can result in compressors operating in conflict with each other, short-cycling, or blowing off—all signs of inefficient system operation.

Individual Compressor Controls
Over the years, compressor manufacturers have developed a number of different types of control strategies. Controls such as start/stop and load/unload respond to reductions in air demand by turning the compressor off or unloading it so that it does not deliver air for periods of time. Modulating inlet and multi-step controls allow the compressor to operate at part-load and deliver a reduced amount of air during periods of reduced demand. Variable speed controls reduce the speed of the compressor in low demand periods. Compressors running at part-load are generally less efficient than when they are run at full-load.

Multiple Compressor Controls
Systems with multiple compressors should use more sophisticated controls to orchestrate compressor operation and air delivery to the system. Network controls use the on-board compressor controls’ microprocessors linked together to form a chain of communication that makes decisions to stop/start, load/unload, modulate, and vary displacement and speed. Usually, one compressor assumes the lead role with the others being subordinate to the commands from this compressor. System master controls coordinate all of the functions necessary to optimize compressed air as a utility. System master controls have many functional capabilities, including the ability to monitor and control all components in the system, as well as trending data, to enhance maintenance functions and minimize costs of operation. Most multiple compressor controls operate the appropriate number of compressors at full-load and have one compressor trimming (running at part-load) to match supply with demand.

Pressure/Flow Controllers
Pressure/Flow Controllers (P/FC) are system pressure controls that can be used in conjunction with the individual and multiple compressor controls described above. A P/FC does not directly control a compressor and is generally not part of a compressor package. A P/FC is a device that serves to separate the supply side of a compressor system from the demand side, and requires the use of storage. Controlled storage can be used to address intermittent loads, which can affect system pressure and reliability. The goal is to deliver compressed air at the lowest stable pressure to the main plant distribution system and to support transient events as much as possible with stored compressed air. In general, a highly variable demand load will require a more sophisticated control strategy to maintain stable system pressure than a consistent, steady demand load.

Source: http://www1.eere.energy.gov/industry/bestpractices/pdfs/compressed_air7.pdf

Monday, March 14, 2011

Compressed Air Storage Strategies

Compressed air storage can allow a compressed air system to meet its peak demand needs and help control system pressure without starting additional compressors. The appropriate type and quantity of air storage depends on air demand patterns, air quantity and quality required, and the compressor and type of controls being used. An optimal air storage strategy will enable a compressed air system to provide enough air to satisfy temporary air demand events while minimizing compressor use and pressure.

The use of air receivers is especially effective for systems with shifting air demand patterns. When air demand patterns are variable, a large air receiver can provide enough stored air so that a system can be served by a small compressor and can allow the capacity control system to operate more effectively. For systems having a compressor operating in modulation to support intermittent demand events, storage may allow such a compressor to be turned off. By preventing pressure decay due to demand events, storage can protect critical end-use applications and prevent addi-tional units from coming online.

Air entering a storage receiver needs to be at a higher pressure level than the system pressure. A good air storage strategy will allow the differential between these two pressure levels to be sustained. To accomplish such a pressure differential, two types of devices can be employed: Pressure/Flow Controllers (P/FC) and metering valves.

A P/FC is a device that serves to separate the supply side of a compressed air system from the demand side. In a system that employs P/FCs, the compressors generally operate at or near design discharge pressure to ensure that the P/FC receives air at a higher pressure level than it will discharge into the system. This allows the pressure in the demand side to be reduced to a stable level that minimizes actual compressed air consumption. P/FCs are added after the primary receiver to maintain a reduced and relatively constant system pressure at points of use, while allowing the compressor controls to function in the most efficient control mode and discharge pressure range. Properly applied, a P/FC can yield significant energy savings in a system with a variable demand load. See Figure 1.


For situations in which just one or a few applications have intermittent air demand, a correctly-sized storage receiver close to the point of the intermittent demand with a check valve and a metering valve can be an effective and lower cost alternative. For this type of storage strategy, a check valve and a tapered plug or needle valve are installed upstream of the receiver. The check valve will maintain receiver pressure at the maximum system pressure; the plug or needle valve will meter the flow of compressed air to “slow fill” the receiver during the interval between demand events. This will have the effect of reducing the large intermittent requirement into a much smaller average demand. See Figure 2.


Sunday, March 13, 2011

Alternative Strategies for Low-Pressure End Uses

Compressed air is expensive to produce. Because compressed air is also clean, readily available, and simple to use, it is often chosen for applications in which other methods or sources of air are more economical. To reduce compressed air energy costs, alternative methods of supplying low-pressure end uses should be considered before using compressed air in such applications. Many alternative methods of supplying low-pressure end uses can allow a plant to achieve its production requirements effectively.

Before deciding to replace a low-pressure end use with an alternative source, it is important to determine the minimum practical pressure level required for the application.

Alternative Applications to Low-Pressure End Uses

Existing Low-Pressure End Use: Open blowing, mixing
Potential Alternatives: Fans, blower, mixers, nozzles
Reasoning: Open-blowing applications waste compressed air. For existing open-blowing applications, high efficiency nozzles could be applied, or if high-pressure air isn’t needed, consider a blower or a fan. Mechanical methods of mixing typically use less energy than compressed air.

Existing Low-Pressure End Use: Personnel cooling
Potential Alternatives: Fans, air conditioning
Reasoning: Using compressed air for personnel cooling is not only expen-sive, but can also be hazardous. Additional fans or an HVAC upgrade should be considered instead.

Existing Low-Pressure End Use: Parts cleaning
Potential Alternatives: Brushes, blowers, vacuum pumps
Reasoning: Low-pressure blowers, electric fans, brooms, and high-efficiency nozzles are more efficient for parts cleaning than using compressed air to accomplish such tasks.

Existing Low-Pressure End Use: Air motors and air pumps
Potential Alternatives: Electric motors, mechanical pumps
Reasoning: The tasks performed by air motors can usually be done more efficiently by an electric motor except in hazardous environ-ments. Similarly, mechanical pumps are more efficient than air-operated double diaphragm pumps. However, in an explosive atmosphere and/or the pumping of abrasive slurries, the application of a double diaphragm pump with appropriate pressure regulating and air shut-off controls may be appropriate.

Case Study: Low-Pressure End Uses are Replaced with Alternative Applications

A bottling plant was using compressed air in some applications that could be better supported with less energy-intensive methods. The plant was cooling and hardening bottlenecks by blowing cool, compressed air on them. Also, some of the blow mold machines were continuously blowing compressed air through air jets onto the pre-form feed lines to prevent them from jamming. Lastly, the plant’s stackers in the packaging area were using compressed air-operated venturi vacuum producers to pick up and position dividers between layers of bottles. To cool the bottlenecks, the application of a small blower that would blow cool air from chilled water was recommended. The installation of an electromechanical vibrator was identified as the best way to prevent the feed lines from jamming. Finally, a central vacuum system having energy costs that were 30% lower than that of the venturi devices was shown to be as effective as the existing system. The annual compressed air energy savings from implementing these simple modifications was $80,000.

Source: http://www1.eere.energy.gov/industry/bestpractices/pdfs/compressed_air11.pdf

Saturday, March 5, 2011

How An Air Compressor Works

There are many things that you might want to know about how an air compressor works.

Compressed Air Operations ManualYou will be able to find many interesting pieces of information out about the air compressors, and you should be able to know how they work. This is a very important factor in the overall impression of the air compressors.

First of all, the air compressors are going to harness the wind at an amazing rate. This is something that many people have wanted to do because air is something that is very useful. The wind can show us that. There is nothing like being able to sit down on a windy day and know that you are going to be able to get the most out of your air compressors. However, you have to understand how they work, first of all.

There are many different types of air compressors. Some are used in building and creating, and some are used in order to convert air to things that we can use, like breathable gas. Most of the time they work in the same way.

They work through using a chamber. The chamber is pressurized, and this pressure is what leads to the harnessing of the air. The air is harnessed through the pressure. This is often hard to comprehend. However, if you think about the way that it works, it is very simple. The air is pulled in through an opening which it cannot exit from. The air enters a chamber and more and more air is pulled in. it is not simply allowed to fill, but more air is pulled in than there is room for. The air compressor continues to pull in more and more air so that it is very tight. Then, the air is compressed even further. After this process is done, the air compressor is full.

Because the way that the chambers inside of the machine work, and because of the very small nozzles, the air is forced out with great speed when it is finally released. This means that the air compressors can be hooked up to anything and then the air can be used. The air compressors themselves simply gather the air into them and then press the air very tightly. The machines are able to do this through pressure. Once the air has been held tightly, it can be released and can be very powerful. It is the release of this air that is what causes it to be used. The air is pushed out of the nozzles at a great speed. However it is pushed out at a very controlled speed. You have complete control over the air.

You can use the air compressors for many things. One of the things that it is used for is to hook up to a nail gun. This helps to drive the nails into the wall at a much faster and stronger pace than a hammer. You can build something much faster this way and it is going to be much easier for you to use. This is a very popular use for the air compressor because it is going to allow you to be sure that you have made the most out of the air. It can also be used in things like power washing. Here, it is hooked up to spray washers or other items and when the air is released, the washers will do their job much better. This way, the air works to propel the water and it can get done much faster. There are also air compressors that aide people. For instance, one of the most popular types of air compressors is the kind that converts the gasses into breathable air so that a person can go diving and still be able to breathe. This is a very popular type of air compressors and it works in the same way. These are very different from the main types of air compressors though. With these, the air is not released in the same way, and it is not sent out in such a hurry. With the other types of air compressors, it is.

Yet you have to be very careful with the air compressors. You should be sure to only use the air compressor for what it is intended. Doing something else with the air compressor, no matter how it benefits you and what you want to accomplish, is going to be bad for the air compressor. You want to be sure that you are able to use this for years and years, so be absolutely sure that you are only using it for what it is meant to be used.

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