Gas Compressor Types
Sliding Vane | Reciprocating | Rotary Screw
Sliding Vane: top
Operation of Sliding (Rotary) Vane Compressor
A sliding (rotary) vane compressor has a solid rotor mounted inside a water jacketed cylinder, similar to that of a jacketed water section of a reciprocating cylinder. The water jacket around the cylinder is used for cooling. The rotor is filled with blades that are free to move in and out of the longitudinal slots in the rotor. Blade configurations range from 8 to 12 blades, depending upon manufacturer and pressure differentials. The blades are forced out against the cylinder wall by centrifugal force, creating individual cells of gas which are compressed as the rotor turns. As it approaches the discharge port, this area is reduced and the gas discharged.
EnerSource Compression Systems utilizes the following manufacturers' sliding vane compressors:
Operation of a Reciprocating Compressor
A reciprocating compressor consists of a crankshaft (driven by either a gas engine, electric motor, or turbine) attached to a connecting rod, which transfers the rotary motion of the crankshaft to a crosshead. The crosshead travels back in forth in a crosshead guide. The crosshead converts the rotating motion to a reciprocating motion. The piton rod is attached to the crosshead and the piston (which is contained in a cylinder) is attached to the piston rod. The piston acting within the cylinder then compresses the gas contained within that cylinder. Gas enters the cylinder through a suction valve at suction pressure and is compressed to reach desired discharge pressure. When the gas reaches desired pressure, it is then discharged through a discharge valve. Desired discharge pressure can be reached through utilization of either a single or double acting cylinder. In a double acting cylinder, compression takes place at both the head end and crank end of the cylinder. The cylinder can be designed to accommodate any pressure or capacity, thus making the reciprocating compressor the most popular in the gas industry.
EnerSource Compression Systems utilizes the following manufacturers' reciprocating compressors:
Operation of a Rotary Screw Compressor
The rotary screw compressor is a positive displacement compressor, made of two intermeshing helical rotors contained in the housing. The driving rotor is usually made of four lobes and the driven rotor usually consists of six lobes. As the helical rotor grooves pass over the suction port they are filled with gas. As the rotors turn, the grooves are closed by the housing walls, forming a compression chamber. to provide lubrication, sealing, cooling and avoid any metal to metal contact, lubricant is injected into the compression chamber. As the rotors mesh, the compression chamber volume decreases, compressing the gas/lubricant mixture toward the discharge port where it exits as the chamber passes over the port. Most manufacturers build a slide stop valve into the casing that can be actuated either manually or with an air or hydraulic piston. This variable volume ratio allows the packager to customize the built in compression ratio as closely as possible to the actual field conditions. Later, the operator can adjust his compression system to meet changing conditions.