Components of a Screw Air Compressor

Learn about each components of a screw air compressor and their function

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The Different Components of a Screw Air Compressor and How They Function

Now that you know what a screw air compressor is and how it works, it's time to learn about the components that make up the compressor. A screw air compressor is a versatile and important machine for a range of industries. Each industrial air compressor shares a list of necessary parts and how they interact. We discuss the components of a screw air compressor and their functions.


Screw Element

The most important part of any high-quality screw air compressor is the screw element. The screw element is also known as the air-end. The screw element is built up of a variety of components to ensure efficiency, the components will be explained below.


The rotors are a critical element of the screw air compressor and are a centralised component in the compressor process. These rotors come in pairs (the male and female rotor) and are built inside cylinders, where the rotations occur. When the screw air compressor is powered on, the rotors rotate at a high speed to create a pipeline for suctioned air to move through. The air is than compressed and discharged out.

Compression Cylinders

The cylinders are a mainframe for the screw air compressors and are built to fit the individual compressor unit. The air that is collected runs through a cylinder’s chambers and into the spinning rotors. A screw air compressor can be single stage or two stage and this can determine the number of cylinders the machine has, and the pressurisation amount it can produce. The most prominent cylinder materials are cast iron and steel.

Air Filters

The inlet air filter can be found just inside the opening valve of the screw air compressor. The air filter minimises damage to the inside of the screw compressor by matching dust, moisture and air particles. Other air filters could also be used for additional cleaning and protective layers by being set within chamber components. Consider the cool and clean air when choosing the location for the air filter.

Oil Filters

The oil filter works to both clean and maintain the purity of the compressed air. In order to ensure oil lubrication is sifted from compressed air properly in oil-injected rotary screw compressors, the oil filter is placed within rotating chamber walls and near discharge valves. Screw air compressors can produce high heat, but oil lubrication can provide the cooling needed to keep the compressor safe. Most oil filters are installed with bypass valves aswell.

Oil Cooler

Compressor air can generate lots of heat. Compressor oil which is used for sealing the rotors, lubrication and cooling, passes through the cooler before being circulated back to the rotary air compressor. Cool and clean air is required in the cooler to keep the oil at that optimal temperature range.


To ensure rotors are secure and rotate evenly, bearings are placed on both rotor ends. Other bearings are installed in key places in the screw air compressor but the most important is the radial-load bearings and the axial bearings.  There are a variety of design modifications when it comes to bearings and this depends on the size and expectations of your screw air compressor, and whether the compressor is oil-lubricated or oil-free. However, bearings are typically anti-friction and anti-corrosive.


Hoses are needed in rotary screw air compressor systems when components are in different locations and oil and air needs to be moved between them. The requirements of heat and pressure must be considered when finding a hose for your rotary screw compressor system. To protect the hose from damage, they must be placed away from any hot or sharp components.

Suction Valve

Most screw air compressors have the suction valve sitting atop for initial retrieval. Once required, the suction valve will open to allow air inside and become trapped within the two rotors. The three main types of suction valves are the poppet valve, the plate valve and the ring valve. Each consists of different shapes to create the ideal air flow for operation types.

Discharge Valve

Discharge valves sit on the opposite end of the suction valve to end the compression cycle. The air that has now been pressurised is received by the discharge valve to be released into a storage tank or a discharge pipe for immediate application. The discharge valve acts as a critical regulatory agent and your machine, nearby personnel and immediate work environment could be in danger if the discharge valve is malfunctioning.


A screw air compressor requires a reliable motor as the use of these compressors are generally large-scale. Most motors will come electrically powered. The motor of the screw air compressor powers the rotation of the rotors and the entire compressor. To ensure safety to your compressor, the motors in newer machines can be monitored with smart control systems.

System Control

With the system control, the operator can monitor the screw air compressors health and overall output. The system control will monitor the various components of the compressor and the compressors operating, idling or stop parameters. This system allows for safe monitoring of your screw air compressor.

Storage Tanks

Commonly screw air compressors will come with a storage compressor tank that may vary in size depending on the application. The pressurised air is received from the discharge valve into the storage tank. The air sits in the storage tank safety and maintains its pressure until use.

Oil Separators

The separator tanks act as another line of defence against oil and gas mixtures in oil-lubricated screw air compressors. It is important in oil-lubricated screw air compressors to filter and clean out excess oil from newly compressed air. An oil separator will ensure little or no oil residue is found in the pressurised air.

Maintaining your Screw Type Air Compressor

With regular service and maintenance, you can avoid compressor downtime due to a dysfunctional component. A dysfunctional component can also cause serious issues to your compressed air system. Along with our proven quality products we also provide exceptional service to ensure that your compressor is running efficiently. We are your partners in compressed air. Explore the ALUP screw air compressor range.