Why Should I Buy a Rotary Screw Compressor?
Unlike piston compressors, in screw air compressors, there are no valves or other mechanical forces that can cause unbalance. This allows a rotary screw compressor to operate at high speeds while combining a large flow rate with small exterior dimensions. The ideal applications of rotary air compressors are continuous, workplace and industrial applications. There are two primary versions, oil-free and oil-injected, with options of fixed speed or variable speed drive operation.
Types of Rotary Screw Air Compressors
Rotary screw air compressors are also available in two primary applications: oil free and oil injected. Here's a breakdown:
Oil Free - External gears synchronise the position of the counter-rotating screw elements, and because the rotors do not come in contact and create friction, no lubrication is needed within the compression chamber. As a result, the compressed air oil-free.
Precision engineering within the housing keeps pressure leakage (and drops) from the pressure side to the inlet at a minimum because the internal pressure ratio is limited by difference in air temperature between the inlet and discharge ports, oil-free screw compressors are frequently built with several stages and inter-stage cooling to maximise the pressure reach.
The gearbox driving the mechanism does contain lubricants; oil-free refers to the compression chamber itself, and the delivered air is free of foreign contaminants beyond those found inherently in the air that passes through the intake.
Oil Lubricated - In liquid-injected rotary screw air compressors, a liquid is injected into the compression chamber to cool and lubricate the compressor elements moving parts, to cool the air being compressed in the chamber, and to help minimise leaks from returns into the chamber during discharge.
While oil is the most common liquid used today because of its lubricating and sealing properties, water and other polymers are sometimes used. The oil is then separated and passes through a filter and cooler before it cycles back into the process again. The compressed air can still be hot and often times is run through a cooler, depending on end usage.
Common Screw Compressor Questions Answered
What is a screw compressor?
A rotary screw compressor is one of the two types of positive displacement gas compressor. It uses two rotors to create the pressured needed to compress air.
How does a screw air compressor work?
The main screw compressor parts are the male and female rotors, which rotate in opposite directions. This draws in air that is compressed as the space between the rotors and their housing decreases.
What is the difference between a fixed speed and variable speed drive compressors?
The basic difference between the two technologies can be found right in the name:
- Fixed speed compressors run at continuous fixed speed
- Variable speed drive (VSD) technology turns the motor at the appropriate speed in relation to the amount of air that is required
What are the advantages of a rotary screw compressor?
The most important benefits of rotary screw air compressors are:
- Energy efficiency
- Low noise output
- Small footprint
- Continuous operation at temperatures of up to 46°C
- Low oil carry-over (as little as 3 ppm) in oil-lubricated machines
- Zero loss of capacity over time
- Life expectancy between 60,000 - 80,000 hours
What are rotary compressors used for?
The benefits of a screw compressor are particularly important for manufacturing, where a stopped compressor will impact production, and sectors where air demand is difficult to predict or control.
Which is better, a rotary compressor or a piston compressor?
Unlike piston compressors, rotary screw compressors have no valves or other mechanical forces that can cause unbalance. This allows a screw compressor to:
- Operates at high speeds
- Combine a large flow rate with small exterior dimensions
There are many reasons why rotary screw compressors are in such high demand: They are very versatile, reliable, efficeint, quiet and there are many different versions of this popular allrounder. But which one is right for you? Discuss the options for your business by clicking the button below to get in contact with us.