1. Single-acting compressor

In a single-acting compressor, the piston compresses air during only one stroke or direction, typically during the downward stroke. The upward stroke is usually used for the piston to draw in fresh air for the next compression cycle. Single-acting compressors are more straightforward in design, cost-effective, and suitable for applications requiring lower output capacities.

2. 2. Double-acting compressor

 In a double-acting compressor, the piston compresses air during both the upward and downward strokes. This occurs because the compression chamber is sealed on both ends. As a result, double-acting compressors produce compressed air with every stroke, resulting in higher efficiency and output compared to single-acting compressors. Double-acting compressors are commonly used in industrial applications that require higher output capacities.

The choice between a single-acting and double-acting compressor depends on factors such as the required output capacity, application, efficiency requirements, and cost considerations.