The screw compressor is designed to lower the pressure using the rotational movements of the rotors. They relate to rotary compressor devices. Despite the fact that the equipment appeared in the mid-30s, it is currently one of the most popular. Its main advantages are small dimensions, automatic operation, profitability, etc.
When installing it, do not use a special foundation, since the level of vibration has low rates compared to other models. An air-screw compressor replaced other types of apparatus.
It is capable of
compressing air up to 15 atmospheres. Furthermore, the productivity reaches 100 m³ / min.
Advantages
Compared to other devices, a screw compressor has several advantages:
- Low oil consumption, which directly affects the quality of the supplied air. It is used in purified form for various pneumatic equipment. Moreover, the installation of additional filters is not required.
- Low noise and vibration. As mentioned earlier, due to its small size, installation is carried out without a special sound-absorbing foundation. This feature helps to equip various portable devices with air.
- The screw compressor is air-cooled. It helps not only to cool different elements, but also to heat the premises due to the secondary heat generated.
- Ability of automatic functioning, ease of installation and operation. The equipment is controlled by special automatic systems.
disadvantages
Among the negative sides, one can single out the high cost and complexity of the design. In addition, the device requires additional equipment for the removal of hot air, which is necessary for heating the room. It is forbidden to use screw compressors in an environment with aggressive gases.
Screw compressor device
The simplest equipment has the following elements:
- A filter that serves to clean the air that enters the working element. As a rule, it consists of two parts. The first is mounted on the body, the second is in front of the valve.
- Suction valve. When the compressor stops, it serves to prevent oil and air from being removed from the unit. It is controlled by pneumatics. In appearance, it is no different from a conventional spring valve.
- The main part is a screw block. There are two connected rotors made of stainless steel. The cost of such an element is quite high. Its design provides a thermal controller that serves to stop the engine when the temperature reaches 105º degrees.
- Drive unit. It consists of two pulleys installed in the engine and rotor, serves to increase or decrease the speed of rotation. The higher it is, the more air will be compressed. However, the operating pressure is reduced.
- The rotor speed depends on the pulleys.
- Motor. Rotational movements are carried out by belt transmission. Its package includes a thermal sensor that turns off the engine when high temperatures are reached. In addition, it prevents various emergencies.
- Oil filter. Cleans oil for screw compressors before it enters the engine.
- Oil separator. Serves to separate air from oil due to centrifugal force.
- Oil separation filter. Cleans grease after separation from air.
- Safety valve. It works when the pressure in the oil separator exceeds the permissible norms.
- Thermostat. Regulates the temperature of the oil composition.
- Oil cooler. After separation from the air, the oil enters a special tank where it is cooled.
- Air cooler. To supply air in the room, reduce its temperature to 20º degrees.
- To pump the above component is a fan.
- Relay. Provides automatic operation of the unit, performs the function of an electronic control system.
- To control the pressure inside the unit, a pressure gauge is installed.
- Minimum pressure valve. It is in the closed position until the pressure exceeds the 4 bar mark.
The screw compressor is placed in the housing. It is made of stainless steel.
Its surface is treated with a special substance that is not exposed to oil and other substances.
Screw compressor: principle of operation
Air from the atmosphere enters through the valve into the rotor mechanism, before being cleaned in the filter. Next is mixing with oil. Then it enters a special container for compression, while doing the following:
- eliminates the gaps between the screws and the housing, so that the appearance of leaks is minimized;
- ensures that both rotors do not touch each other;
- removes heat that is generated during the compression process.
The compressed mixture enters the oil separator, where it is divided into components.
The separated oil is cleaned in the filter and fed back to the unit; if necessary, it is cooled. Air also enters the air cooler and then is supplied from the compressor.
What operating modes exist?
A screw compressor, the principle of operation of which is described in the previous paragraph, can operate in such modes:
- Start In this mode, the screw compressor is started and connected to the power grid according to the "star" scheme. After a few seconds, he switches to the triangle pattern.
- Work mode. The pressure in the compressor begins to increase. When a certain point is reached, the unit idle is switched on.
- Idling. In this mode, the rotor rotates, during which there is a movement of the gaseous medium necessary for cooling the air. It allows you to put the compressor into standby mode before turning off the unit.
- Standby mode. The screw compressor will perform this function until the pressure indicator drops to the minimum value.
- Stop When this mode is turned on, the compressor equipment goes to idle, and then completely turns off.
- Alarm-stop. It is used when it is necessary to urgently disable the air screw compressor.
Device repair
With good service, the element can function more than 50 thousand hours. Like any device, over time it is necessary to repair screw compressors. This equipment contains complex mechanisms and various configurations.
Quite often, in such a device, electronics fails. Compressor plants have sophisticated electronic systems that can burn out. Therefore, it is necessary to repair it, and in more complex cases, to replace it. This can be done by highly qualified specialists. The cost of the control unit is quite high. If it has a dehumidifier, repairing screw compressors will be even more costly, since the equipment is a complex mechanism.
Cost
As mentioned earlier, screw compressors are on the market in a very wide range.
The cost depends on the power of the equipment, as well as technical specifications. Its price range ranges from 250 to 700 thousand rubles.
Reviews
Many users of screw compressors note the high performance of the equipment.
Since it has small dimensions, it can be used at various construction sites, without spending a lot of energy during transportation. Among the shortcomings highlight the high cost and complexity of the design.