Screw Compressor


This is a 3D model of a Screw Compressor.

3D Model Annotations

Master Screw

The master screw is connected directly to the main drive shaft. Rotary force from the drive shaft is transferred to the master screw, which causes it to rotate. The rotary motion is then further transferred from the master screw to the slave screw, as both are mechanically connected. Fluids trapped between the master and slave screw are transferred from the suction side of the pump to the discharge side.

Slave Screw

The slave screw is identical to the master screw, except that it has no drive shaft. It rotates only when driven by the master screw.

Drive Shaft

The shaft transfers the rotary motion created by the electric motor to the master screw. The shaft is held in alignment by bearings.


The casing houses the helical screws, bearings, moving slide valve and mechanical seals.

Moving Slide Valve (MSV)

The moving slide valve (MSV) regulates flow through the pump. As the valve moves towards the hydraulic piston, flow through the pump is reduced. As the valve moves towards the drive end of the pump, flow through the pump is increased. The slide valve is actuated by a hydraulic piston.

Mechanical Seal

A mechanical seal is used to seal the space between the pump shaft and casing. The seal prevents fluids leaking out of the intended flow area.

Hydraulic Actuator

Hydraulic fluid is fed to either side of a piston to actuate the moving slide valve.


Bearings carry the axial and radial loads generated by the pump when it is stationary or in service. The type of bearings used depends upon many factors, although single row ball bearings are considered a suitable bearing for many service applications. This pump uses double and single row anti-friction ball bearings.


Fluid enters the pump through this connection. This pump is a positive displacement pump and can thus pump liquids, vapours, and gases.


Fluid is discharged from the pump through this connection.

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