Why Choose Screw Compressors?

A rotary screw air compressor is a machine that uses the principle of rotation to compress atmospheric air, because of this, screw compressors are also known as rotary compressors.

Screw compressors are a great choice for industrial applications in Manufacturing, Engineering, and Distribution facilities, especially as these machines have the ability to run continuously. Examples of applications that can be powered by rotary screw compressors include:

  • Food processing
  • Packaging machines
  • Metal cutting
  • Cooling and heating

Even for the applications above, choosing whether to opt for a screw compressor really comes down to your specific needs, which is why Direct Air offer expert recommendations and bespoke solutions.

 

How Does a Screw Compressor Work?

A rotary screw air compressor works by drawing air in and compressing it between the male and female rotors as they revolve in opposite directions. As the space between the rotors narrows the air is compressed, resulting in compressed air that is positively displaced out of the outlet. This cycle repeats until the rotor reaches maximum speed, at which pressure inside the machine will be at its maximum point to provide that continuous supply of compressed air that so many industries require.

Screw compressors can be single stage, meaning air is pushed from only one end of the chamber to the other. Therefore, multi-stage screw compressors compress air from both ends of the chamber simultaneously, as they are able to change direction.

Advantages of a Screw Compressor

Durable – Rotary screw air compressors have a considerably long lifespan compared to other types of air compressors.

Low noise – Due to the smooth movement of the rotating shaft, rotary screw compressors operate quieter than other compressor types. This makes the compressors ideal for facilities where employees are working near to the compressed air system, as it acknowledges health and safety factors.

High demand – Rotary screw air compressors can operate continuously as they run at a lower temperature, so overheating isn’t an issue. Therefore, these compressors can meet consistently high demands as there’s no delay in waiting for the receiver tank to fill up, meaning air can be used right away.

Energy efficient – Due to the screw air compressor being less likely to overheat, it means less heat is produced to become wasted energy in the atmosphere.

 

Screw Compressors vs Piston Compressors

In comparison to pistons, screw compressors do not have rods, valves, pistons, and other parts that pulsate during the compression of the air. Therefore, screw compressors operate a lot smoother than piston compressors and due to no thudding sounds from these moving parts the noise level is significantly reduced.

Also due to the relatively low number of mechanical parts and continual, smooth rotation of the central screw shaft, screw compressors have little wear and tear. This means that the risk of a machine break-down is much lower.

Things to consider with Screw Compressors

Despite screw compressors being an excellent solution for many applications, there are some things to consider…

The screw compressor’s advanced design compared to the pulsating, noise generating mechanisms of other compressor types means that this of course comes at a price. Therefore, you’ll often find that screw compressors come at a higher price than their piston counterparts.

As this compressor type is designed to function in a continual motion, intermittent loads and regular stopping and starting aren’t ideal for screw compressors.

Although the reduced moving parts in compressors mean reduced wear and tear, if something does require repairing it can often be more complicated. This is where our qualified Direct Air Service & Maintenance engineers are on hand to step in and help!

Oil-Lubricated Screw Compressors

Lubricated screw compressors use oil in the chamber where air is compressed to cool and lubricate the compressor as this helps form a seal and dampen noise levels.

These types of compressors can be ideal for applications where the compressed air doesn’t come into direct contact with an end product that is consumable.

Oil-Free Screw Compressors

Alternatively, if your compressed air is coming into direct contact with your consumable end product, oil free compressors can be a smart choice. This would be most apparent in Food & Beverage and Pharmaceutical production industries.

Whether you opt for an oil-lubricated or oil-free screw compressor, don’t forget that the connecting compressed air treatment is a vital requirement to complete your system.