There are two basic principles of air compression, and one of those is displacement compression. Many types of compressors are classified as displacement compressors, one of which is the piston compressor. A piston compressor is the oldest and most common type of industrial compressor.
This type of air compressor uses principles of displacement to increase the pressure of the enclosed volume of gas or air. They are available in a range of configurations, from single-acting, double-acting, oil-lubricated or oil-free. A common configuration is a double-acting design, which features an L-configuration with one vertical, low-pressure cylinder and one horizontal, high-pressure cylinder. The oil-lubricated designs use splash lubrication or pressure lubrication and oil-free designs feature piston rings or toothed walls.