Keep your compressor in top condition, with our great articles on air compressor parts. Buy only the right stuff for your compressor.
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Air compressors have of many parts that have to be serviced, can break down or get dirty.
When you own an air compressor, or consider buying one, it’s handy when you know a little about the different compressor parts.
Even when you don’t want to do any service or repair on the machine yourself, knowing just a little bit about the various part can help a lot when buying a compressor or when talking to the repair guy.
Here’s an overview of the various air compressor parts you can find on your machine.
Not all parts can be found on all types of compressors.
Compressor Air filters
Other air compressor parts
Compressors have different valves, all with a different purpose, I’ll list the most important ones:
Inlet / outlet valves on reciprocating piston compressors regulate the intake and exhaust of the piston chamber.
They make sure that the air can’t flow back. They are mostly operated (opened/closed) by the pressure difference in the system (so, not mechanically like in your car).
Air Compressor Check Valves
The Air compressor check valve can be found in various locations.
There are at least 2 check valves in your screw compressor.
They are also found between your reciprocating compressor and the air receiver (tank).
This is to make sure that when the compressor is stopped, no air can flow back into the compressor.
After cooler with condensate trap. Photo: Atlas Copco
Every compressor has some sort of cooler. Why? When air is compressed, a lot of heat is generated (read: most of your expensive energy will be converted to heat, only 4% will be compressed air energy).
To get rid of all this heat, your air compressor has 1 or more coolers.
Small air compressors (the reciprocating piston type) have the simplest form of cooler: fins around the discharge pipe (the pipe between your compressor and the receiver/tank).
Bigger air compressors (of the rotary screw type) have normally 1 oil cooler and 1 after cooler. The oil-cooler will cool the hot oil before it is returned to the compressor element.
The after cooler will cool the compressed air before it comes out of the compressor.
Many times, both coolers are mounted next to each other, with one fan to blow cooling air through it.
Air compressor Motors
Most stationary and small moveable air compressors are powered by electro motors. Bigger portable compressors are usually powered by diesel engines. Very big compressors in large plants (like oil refineries) are sometimes power by steam turbines (both for safety and because steam is cheaper than electricity for them).
The electromotor used are just standard off-the-shelve electro motors. When you want to buy a replacement motor, always check the power (kW of HP) and the mechanical connections.
Some motors are connected to the compressor with a direct coupling. Others are connected using pulleys
Air compressor pulley
The pulleys on the compressor and motor are usually not of the same diameter. There’s a so called drive ratio, which allows the compressor to turn slower than the electro motor (but with more torque). When ordering new pulleys, make sure that the outer size and the size of the shaft are the same.
Sometimes it’s necessary to renew the pulley together with the belts. To remove the pulley from the shaft, use a pulley puller (a special device, can’t do it without it).
To mount the new pulley back on the shaft can be tricky. If you notice that you can’t just fit it on there, the hole is too small (or the shaft is too thick). That’s normal. You need to heat up the pulley with some sort of torch (or oven). When it’s hot enough (when you spit on it and you spit starts ‘dancing’, it’s hot enough), slide the pulley over the shaft in one smooth motion. Don’t stop, as soon as the hot pulley touches the cold shaft, it will lose heat and shrink (and the shaft will get hotter and grow).