Posts

Showing posts from March, 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 mai

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. Se

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: 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,

Eliminate Inappropriate Uses of Compressed Air

Image
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 Pers

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

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 Contamina

Determine the Cost of Compressed Air for Your Plant

Image
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 compresse

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 y

Compressed Air Storage Strategies

Image
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

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

How An Air Compressor Works

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