3.3.1. General


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Fig. 3.23: BOGE piston compressor
Piston compressors operate according to the displacement principle. The piston intakes air through the intake valve during the downwards stroke. It closes at the start of the downwards stroke. The air is compressed and forced out of the pressure valve. The piston is driven by a crank drive with crankshaft and conrods.

Piston compressors are available with one and several cylinders, and in one and multiple-stage versions.

Multi-cylinder compressors are used for higher outputs, multi-stage compressors for higher pressures.


Single stage compression

Compression to the final pressure in one piston stroke.

Two stage compression

The air compressed in the cylinder in the first stage (low pressure stage) is cooled in the intermediate cooler and then compressed to the final pressure in the second stage (high pressure cylinder).

Single action compressors

One compression action with one rotation of the crankshaft.

Double action compressors

Two compression actions with one rotation of the crankshaft.
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Fig. 3.24: Principles



Piston speeds

With compression the compression speed or even the motor speed is of secondary importance. The most important factor in assessing wear is the piston speed. So a compressor with a low speed and large stroke can have a high piston speed. In contrast, compressors with high speeds and a small stroke can have low piston speeds. The piston speed, measured in m/s, is extremely low with BOGE piston compressors. This means minimal wear.