Rotary Screw Air Compressor Types & Working Principle

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Written By Scott Angel

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The compressor’s main job is to pump air for increasing its density. Such condensed air released by the compressor has a high speed and allows it to be used in a variety of applications. Compressors are divided into two types – flow type and positive displacement.

Among them, an axial, radial compressor, whose operation is based on two elements – a movable rotor and a stationary steering wheel. This issue looks different among displacement compressors.

The operation of a positive displacement compressor, for example, diaphragm, screw or piston, depends on the piston moving in the cylinder. The working piston reduces the volume of air and thus increases the pressure in the cylinder. Among positive displacement compressors, rotary screw air compressors are the best choice because they cause the least vibration during operation.

What Is Screw Air Compressor?

Construction of a typical screw compressor is quite simple. The device consists of two types of rotors – convex and concave, which reduce the volume of gas by turning relative to each other.

The sale also includes compressors with a more advanced design. They allow the flow to be adapted to the current demand, using variable engine speed and continuous pressure measurement at the compressor outlet.

Regardless of the solutions implemented, screw compressors are characterized by exceptional energy efficiency and work efficiency, adjusted to the current demand. For this reason, they are used in various industries.

Construction Of A Screw Compressor

The heart of the screw compressor is two impellers – convex and concave placed in the housing. The rotors rotate relative to each other. As a result of this process, the air is compressed in a spiral. Tapered roller bearings are mounted on the ends of the rotors, which ensure the efficiency of the device.

The housing has an outlet and a suction inlet. Air enters through the suction inlet into the space between the rotors. The air volume, after being compressed by the rotors, increases, i.e., the air is compressed and flies out through the outlet. Screw compressors are divided into two types – oil and oil-free compressor. The use of a compressor defines its nature.

Types Of Screw Compressors

In the full range of screw compressors, the industry can choose a variety of models tailored to the needs of the industry. Screw compressors are flexible devices whose work can be adapted to the required performance. Each model can set the pressure range and automatically start and stop the machine according to the pressure transducer. The compressors have remote control and integrated cooling and dryer control.

In addition to traditional screw compressors, there are also variable capacity screw compressors and oil-free screw compressors on the market. Variable-capacity compressors allow you to adjust the amount of compressed air precisely to the needs of the production cycle. Air compressors will work in all applications where the supply of compressed air with varying pressure is of crucial importance.

Oil-free screw compressors are devices that provide compressed air without oil particles. In the compression process, only water is used, which is a natural and most importantly, neutral substance that does not affect the implementation of the industrial process. What’s more, these devices are equipped with filters that allow the elimination of microorganisms (pollen, bacteria, and viruses). Thanks to this, oil-free screw compressors emit air completely clean and environmentally friendly. These ecological devices allow the condensate to be drained directly into the sewage system.

Undoubtedly, modern screw compressors are energy-saving and economical in operation devices, which, depending on the needs, are quiet or muted, transportable, portable or stationary, for use in interiors, production halls or in the open air.

Working Principle Of A Screw Compressor

Those oil compressor in which oil is injected into the compression chamber, are used for mixing materials, supplying tools and cylinders, powder coating, and spraying. Oil in oil screw compressors performs three functions: it lubricates, seals and receives heat released at the compression site.

Thanks to this type of compressor heat up with difficulty, which ensures the possibility of continuous several hours of operation. Oil-free compressors are the second type of screw compressors. The fundamental difference between an oil and oil-free compressor is the material from which the piston was made.

For an oil compressor, this substance is needed to reduce friction between the rotors. The rotors in the oil-free compressor are made of a material that has a low coefficient of friction.

In their case, only a neutral, natural substance like water, is used for the compression process. Due to its characteristics, water does not affect the industrial process. That is why oil-free screw compressors have a wide range of application in industry requiring sterile conditions in pharmacy.

Thanks to the filters they have been fitted with, the air emitted is environmentally friendly. Filters protect against pollen, bacteria, and viruses. The construction of the devices allows condensate to be drained straight into the sewage system. No need for condensate storage makes the tools ecological.

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Oil compressors are much heavier than oil-free, which is why they are usually equipped with wheels to make it easier to move the device. The advantage of an oil compressor is its efficiency and large capacity because it can work continuously and its service is much more comfortable.

Oil compressors are therefore very popular in car workshops and vulcanization plants. It happens that when using such a compressor, oil particles get into the blown air.

This is not an obstacle in activities such as pumping wheels, painting in tinsmith’s and painting workshops, or supplying pneumatic devices. Therefore, oil screw compressors have found full application in the industry.

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