Reciprocating (API 618)

Petrosadid: Reciprocating (API 618)

Reciprocating compressors (API 618), generate gas compression through the use of pistons. These pistons enter and exit a cylindrical mouth, allowing gas in and out of the compressor only when its useful, and without changing its compression process. Because they are cost-effective and have broad output capabilities, reciprocating compressors enjoy an established popularity. Like rotary screw compressors, reciprocating compressors may be portable or stationary air compressors.

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Petrosadid as a supplier in the compressor business, provides HP piston compressor systems for air, natural gas, technical and industrial gases (process gases) with power rates of up to 6,200 kW (8,300 hp) and pressure rates of up to 700 bar (10,150 psi). Petrosadid supply pressure compressor systems which are designed according to international standards, using standard design principles.

Petrosadid: Reciprocating (API 618)

​The vertical reciprocating compressors cover an area of the lower capacity (lower than horizontal reciprocating compressors). They are the optimal solution for low space locations and requirements. Vertical compressors can be configured as a single- to multi cylinder design.

Petrosadid: Reciprocating (API 618)

Flow Control Of Reciprocating Compressors

Valve Unloading – Stepped

Cylinder suction valves are held fully open in some cylinders. This prevents flow in those cylinders. Typically used to reduce flow in one step to 50%.

Simple control system, low cost. On/off control.

Cylinder Volume Pockets

A valve is used to connect a cylinder head to a “dead volume” this reduces “volumetric efficiency” and hence compressor flow. Flow reduction is typically 20%. On/Off control

Valve Unloading - Stepless (eg Hoerbiger “Hydrocom”)

Sophisticated control that holds Cylinder suction valves open for part of each cycle.

Enables smooth flow control from 100% to around 25% flow


Recycle flow control

Allows full flow control but has poorest energy efficiency

Compressor Suction and Discharge Valve


Design of the suction and discharge valves is one of the die more important considerations in the design of the compressor due to its design considerably influences the volume compression and efficiency. Let's remind, that the characteristics of flow and friction losses, generating steam, as it flows drought valves of the compressor and passages, first of all, depends on its speed. As vapor speed through the valves increases, volumetric compression and lower efficiency. Therefore, the valve ports are designed to be as large as possible within an area equal to the cylinder. Big wells permission to use larger size ports. Valves are manufactured with the use of low-weight materials and have a short lift so that they quickly open their maximum flow position. They are also short, straight path thread to reduce friction losses incurred in liquids abruptly change their direction. Valves are designed to minimize the volume needed gap in the cylinder, close tightly, low cost and durable. To facilitate the rapid closing of the valve, the majority of the exhaust valves and some suction valves spring.

All of these design features work in the direction of maximum die operating efficiency of the compressor.

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