Two-stage versus Single-stage Air Compressors

Using compressed air as an efficient kinetic energy resource requires a simple machine and holding tank. All compressors will have the same basic parts: receiving tank, pressure gauge and compression machinery. The identifying difference between two-stage and single-stage compressors is the number of compression cylinders incorporated.

Single-stage air compressors follow a few simple principles. When the compressor’s piston is actuated it literally squeezes the air contained inside its cylinder until the PSI is strong enough to release a one-way valve connection between the cylinder and the receiving tank. As the piston cycles, the receiving tank is filled with compressed air. A pressure switch is located on the receiving tank to regulate the tank's maximum PSI with a mechanical relief valve attached for safety purposes. When the set maximum air pressure is achieved in the tank, a switch connected to the pressure switch will signal the motor to turn off. The pressure inside the receiving tank is continually monitored by the pressure gauge. When the PSI in the receiving tank drops below a preset level, the pressure switch will activate the motor to add more compressed air to restore the overall pressure of the receiver.

A two-stage air compressor follows the exact same principles as the single-stage but there are two actuating pistons. The first stage will produce compressed air at a lower pressure than is ultimately desired for the end use. As the pressure in the first receiving stage builds it supplies air to the second stage's cylinder. The air is again compacted before being released into the output receiving tank. The advantage of a two-stage compressor is that it distributes the work load between two components to achieve a higher level of compressed air without having to overwork a single piston. The higher PSI offerings of two-stage compressors make them the better choice for industrial use and high torque pneumatic tools.

A single-stage compressor is a highly efficient machine. Choosing an oil-less type will ensure long use with little maintenance required. The disadvantage to a single stage compressor is that its output is limited to providing air below 125 PSI.

Two-stage compressors require slightly more maintenance because they have more parts. The advantage is that greater PSI offerings can be efficiently maintained without over-exerting the machine. Two-stage compressors also generate less heat than single-stage compressors do, which means that parts may not wear out as quickly and your compressor will likely have a longer life.