Are you responsible for selecting the air compressor for a new company, project, site or installation? Selecting the right air compressor type and size are critical to the manufacturing process in any new facility. Since there are many different types and sizes of compressed air systems to select from, in this article we discuss how to select the best air compressor that meets your company’s needs.
- Why is compressed air system selection so important?
- How do I select the correct compressor for a new plant?
- What are the capacity and pressure requirements?
- Do we need an oil free air compressor or an oil lubricated air compressor?
- What are the power requirements?
- What are the different types of air compressors?
1. Why is Compressed Air System Selection so Important?
Compressed air is commonly known as the fourth utility in the manufacturing world, but unlike the three other utilities – electricity, gas and water – compressed air cannot be purchased directly from traditional utility companies. Instead, we operate the compressor and treatment equipment that generates the compressed air for the plant’s needs. Other integral components of a compressed air solutions include:
• Compressed air treatment equipment – refrigerated, heatless, heated, blower heated desiccant, membrane dryers, etc.
• Controls – start/stop, load/unload, modulating controls, soft start, variable frequency drives, lead/lag, sequencing, etc.
2. How Do You Select the Right Compressor for a New Plant?
How do we know what compressor size we might need? What is the right type for our application? There are several things that should be considered. The following are some of the basic things to consider when determining the air compressor you may need.
3. What Are the Capacity and Pressure Requirements?
Capacity and pressure requirements are determined by the air requirements in the plant. Check and calculate the Cubic Feet per Minute (CFM) for flow, and BAR, or Pounds per Square Inch (PSI) for the pressure requirements of all the tools and equipment requiring compressed air for plant operation. If those specifications are not available, check with the tool /equipment manufacturers for this information.
After the total CFM requirement is obtained, we recommend adding 25% of your requirements for leaks and future expansion. For the pressure, calculate the maximum operating pressure needed for the plant or based on the pressure requirement provided by the tool/equipment manufacturers, then add approximately 1 BAR for pressure loss due to the distance of the compressor to the point of use, pipe size, turning points, dryer, filters, and other factors.
4. Is an Oil Free Air Compressor or Oil Lubricated Air Compressor Required?
It’s also very important to know the compressed air quality requirements, because that will dictate the type of compressor and associated equipment (dryers & filters) selected. Generally, it is not enough to say we need oil free and dry air without specifying the solid particulate, oil aerosol, and water allowed in the system. Oil free and dry air are relative terms. What may be acceptable for one industry may not be acceptable for others, or it may be acceptable at one usage point but it may not be acceptable at others.
Depending on the class of air quality, an oil flooded air compressor may be sufficient, an oil lubricated air compressor may be suitable with treatment, or an oil free air compressor may be required.
5. What Power Supply Is Available?
Last but not least is the power, which tends to be overlooked or sometimes assumed (although that is not recommended). Making the wrong assumption will cost more money to make the correction and will delay the operation schedule of the facility. These problems are easily avoidable with little attention. Always verify the voltage and amps required to operate the compressor. Also make sure your existing power supply is adequate for your new compressor.
6. What Are the Types of Air Compressors?
Compressors are separated into two major groups, positive displacement and dynamic.
Positive Displacement (Rotary Vane) Compressors
Vane compressors bring in air, trap it, and then reduce its volume mechanically.
Reciprocating Compressors
Reciprocating compressors use a piston driven by a crankshaft to deliver high pressure air. The small size, simple maintenance, and ability to set-up near the point of use are some of the benefits of a reciprocating compressor. Reciprocating compressors are available as oil flooded compressors or oil free compressors, and they are designed to run start/stop, only producing air when needed, which is very efficient.
Scroll Compressors
Scroll compressors use intermeshing spiral scrolls, with one being stationary and the other orbiting in relation to it. Although these compressors are limited in size, they are relatively efficient, oil free air compressors and have low noise levels.
Rotary Screw Compressors
Screw compressors use two mated screws to mechanically reduce the volume of the air. These compressors are typically better for industrial uses, are much more durable, and have a higher performance than reciprocating or scroll compressors. Depending on the application, these are available as oil free air compressors or oil lubricated air compressors.
Summary
These general guidelines will help define requirements for selecting an air compressor for a new plant. Although selection means a lot more than deciding between an oil free air compressor or an oil flooded air compressor, the time invested in defining these requirements will affect plant operating efficiency far down the road. For additional assistance in determining which models will best suit your plant’s requirements, contact Airia Compressed Air Solutions for assistance & pricing.