How is the rotation of the air in the screw rotary?
Usually, the rotary screw compressor uses two female and male rotors (spiral screw) to compress air. The rotors are made of different materials and are perfectly compatible with each other and move at the smallest distance from each other. When the rotors start spinning; Air enters the chamber from one side and gets trapped in it. Since the rotors are constantly rotating, the air is pushed towards the end of the rotors due to the circulation, and fresh air continuously enters the compressor chamber.
Difference of Rotary Screw Compressors and Piston Type
Compared to reciprocating compressors such as piston type, rotary screw is much more expensive; But keep in mind that these types of expensive air compressors can work 24 hours a day, seven days a week, and 365 days a year, without any problems. On the other hand, the capacity (liters of air per second) of rotary compressors is much higher compared to the piston type in general. When you need a lot of air in your workshop or factory; This type of compressor is usually the best choice.
Types of Rotary Screw Compressor
Rotary screw compressors are available in "oil-free" and "oil-lubricated" versions. The general principle is the same in both and still the rotors in both types push the air to one side; But in details, they are completely different. The big difference is in the design of the compressor elements. In case of using the oily type, the correct functioning of the part of the chamber where the compression takes place; It will completely depend on the oil injected into it. If in the oil-free version, as the name suggests; It does not need oil. Oil-free rotary screw The rotors used in oil-free screw compressors are of high quality and there is very little space between their rotors; Of course, they do not contact each other. In case of contact between the two rotors, the parts will be damaged very quickly; That is why they are very expensive. Most of them are used in large factories such as oil-gas-chemical refineries or in large food companies or other spaces where the compressed air must be 100% oil-free (otherwise, oil It can contaminate all kinds of food, products or chemical process).
Rotary screw oil injection
Oil injection models are the most common type of rotary screw compressors. These compressors, as their name suggests; When the air is compressed, the required oil is injected into the chamber (the space where the actual compression takes place). This oil is further separated from the compressed air by a separator, they also have a filter at the compressor outlet, which will eventually contain the least amount of oil in the compressed air.
Although 99.9% of the oil remains in the compressor, there is always a small amount of oil that passes through the separator and leaves the compressor with the compressed air. Therefore, oil-injected rotary compressors do not produce oil-free air and cannot be used in areas that require oil-free air.
But for most factories, workshops and machinery, The presence of a small percentage of oil in the exhaust air of the rotary screw compressor does not cause a problem. In fact, this oil in compressed air helps prevent rusting within the compressed air system and helps machines run smoothly.
Of course, there are more advantages in this type of compressor, which you can use optimally by understanding their operation and working principles.