When the crankshaft pushes the piston up, the air is pushed into a tank with a one-way check valve that does not permit it back into the cylinder. As more air enters the tank, the pressure increases. When the piston is pulled down, new air enters and the process begins again.
The reciprocating compressors are the most common of all the air compressor designs, and are utilized in oil refineries, gas pipelines, chemical plants, natural gas processing plants, and refrigeration plants. A compressor is a component of a vapor compression refrigeration system, which is the most common method for air conditioning of public buildings and residences.
Reciprocating compressors are a specific model of positive displacement compressors, which generally use pistons within cylinders to control the flow of air in and out of the mechanism. Rather then filling and collapsing with air, another type of compressor, the rotary screw compressor, uses two precisely aligned helical screws to collect air through a sealant and release it again by way of the rotating screws.
Reciprocating compressors differ from screw compressors by the method of compression they employ, but are able to be utilized in similar applications. Rotary screw compressors involve lubrication more often then reciprocating compressors, but both can be oil free. The benefits of oilless air compressors are guaranteed clean air, with no oil carryover, cost-efficiency and earth friendliness.
Air compressors are typically made of cast iron, aluminum, stainless steel or a combination of these materials. However, when a light weight compressor is desired, the air compressor may be built from plastic instead. The pistons or other minor components may be made of plastic in small air compressors as well. There are different varieties of reciprocating compressors that are styled depending on the applications.
In a single stage reciprocating compressor, all of the compression takes place in a single cylinder. Multi-stage compressors will compress the air to intermediate pressures in two or more steps before the final desired pressure is reached. Some reciprocating compressors have been known to operate up to six cylinders at once. This allows for higher pressures to be reached, but can limit the cubic feet per minute, or CFM.
These large examples of compressors are powerful and impressive, but the small and portable reciprocating compressors are used as often if not more so, and are therefore just as important. Portable compressors are utilized in industrial companies as well, but by powering small pneumatic tools, such as sand blasters, drills, nail guns and staplers.