A reciprocating air compressor uses positive displacement to function. That means that they generate compressed air through a system of valves and pistons, much like the combustion engine in your car. The fact that pistons help compress the air is why the terms ‘piston compressor’ and ‘reciprocating compressor’ are used interchangeably.
Essentially, a piston compressor contains a valve system and two valve discs. When the piston moves down, it draws air into the cylinder. One of the valve discs folds downward, allowing the air to pass. When the piston moves upward, the large disc also folds upwards and closes. After compression, the compressed air passes through the after-cooler and continues onto the air tank.
Piston compressors are available in different configurations. For instance, there’s a difference between oil-free and oil-lubricated compressors.
There are 4 sub types of reciprocating compressor:
A one-stage compressor has one or more cylinders, each of which compresses air from atmospheric pressure to operational pressure.
A multi-stage compressor has two or more cylinders connected in series in which air is gradually compressed to the needed pressure level. Between steps, the compressed air is cooled with ambient air. This improves efficiency while achieving a much higher pressure level than the one-stage compressor.
These compressors are called ‘separable’ because they are separate from their energy source. They are driven by engines or motors. They are:
You have to keep in mind, however, that these types of reciprocating compressors will need more maintenance and therefore require more maintenance costs than the integral ones.
They are also called high-speed compressors because they operate on a speed between 900 and 1,800 rpm.
These types of reciprocating compressors are called ‘integral’ because their driver is mounted into the frame of the compressor. They are:
They are called ‘low speed’ because they operate at a speed between 200 and 600 rpm.
Piston compressors are suitable for small compressed air requirements. One-stage compressors produce pressures up to about 8 bar, while several stage versions produce up to 15 bar.
Operation should be intermittent. An air-cooled piston compressor’s load level should not exceed 60-70%. After 2 minutes of compression, the compressor must rest for at least 1.5 minutes. We recommend keeping the total compression time per day to approximately 4 hours.
Piston or reciprocating compressors are mostly used in these types of industrial settings:
However, due to the wide variety of reciprocating compressors, they are used in almost every work setting. Although they have more maintenance requirements, they are very energy-efficient.
Although piston compressors are available in lots of different configurations in smaller industries, they are most commonly used in:
As always, everything depends on the purpose of your air compressors. What kind of power would you like to generate? Does your compressor have to be moveable? What kind of maintenance would you prefer?
To make sure you pick the air compressor that fits your needs, get advice from the MARK experts today.