The screw compressor is designed to reduce pressure using the rotational movements of the rotors. They belong 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 size, automatic operation, economy, etc.
When installing it, a special foundation is not used, since the vibration level is low compared to other models. The air screw compressor has replaced other types of air compressors.
It is capable of compressing air up to 15 atmospheres. At the same time, the productivity reaches 100 m³/min.
Dignity
Compared with other machines, the screw compressor has a number of advantages:
- Low oil consumption, which directly affects air quality. Its inpurified form is used for various pneumatic equipment. Moreover, installation of additional filters is not required.
- Low noise and vibration. As mentioned earlier, due to the small size, installation is carried out without a special sound-absorbing foundation. This feature helps to supply air to various portable devices.
- The screw compressor is air-cooled. It helps not only to cool different elements, but also to heat the premises due to the recycled heat.
- Ability to automatic operation, easy installation and operation. The equipment is controlled by special automatic systems.
Flaws
Among the negative aspects are 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 corrosive 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 installed on the body, the second is in front of the valve.
- Suction valve. When the compressor stops, it serves to ensure that oil and air are not 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. Herethere are two connected rotors made of high quality steel. The cost of such an element is quite high. Its design includes a thermal protection controller, which serves to stop the engine when the temperature reaches 105º degrees.
- Drive. It consists of two pulleys installed in the motor and rotor, serves to increase or decrease the rotation speed. The higher it is, the more air will be compressed. However, the operating pressure is reduced.
- Rotor speed depends on pulleys.
- Motor. Rotational movements are carried out by a belt drive. It is equipped with a thermal protection sensor that turns off the engine when high temperatures are reached. In addition, it prevents the occurrence of various emergency situations.
- Oil filter. Purifies oil for screw compressors before it enters the engine.
- Oil separator. Serves to separate air from oil due to centrifugal force.
- Oil separator filter. Purifies grease after de-airing.
- Safety valve. Triggered when the pressure in the oil separator exceeds the allowable limits.
- Thermostat. Regulates the temperature of the oil formulation.
- Oil cooler. After separation from the air, the oil enters a special container where it is cooled.
- Air cooler. To supply air to the room, reduce its temperature to 20º degrees.
- A fan is used to pump the above component.
- Relay. Providesautomatic 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 4 bar.
The screw compressor is placed in the case. It is made of high quality steel.
Its surface is treated with a special substance that is not affected by oil and other substances.
Screw compressor: working principle
Air from the atmosphere enters the rotary mechanism through the valve, before being cleaned in the filter. Next comes the mixing with oil. Then it enters a special container for compression, while fulfilling the following purposes:
- eliminates gaps between screws and body, minimizing leakage;
- makes both rotors not touch each other;
- dissipates heat generated during compression.
The compressed mixture enters the oil separator, where it is separated into components.
The separated oil is cleaned in the filter and returned to the block, if necessary, it is cooled. Air is also drawn into the air cooler and then out of the compressor.
What are the operating modes?
The screw compressor, the principle of operation of which is described in the previous paragraph, can operate in suchmodes:
- 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.
- Working mode. The pressure in the compressor begins to rise. When a certain mark is reached, the idling of the unit is switched on.
- Idling. In this mode, the rotor rotates, during which the gaseous medium necessary for cooling the air moves. It allows you to put the compressor into standby mode before turning off the unit.
- Standby. The screw compressor will perform this function until the pressure indicator drops to the minimum value.
- Stop. When this mode is enabled, the compressor equipment goes to idle, and then completely turns off.
- Alarm-stop. It is used when it is necessary to urgently disable the screw air compressor.
Device Repair
With good maintenance, an element can last over 50,000 hours. Like any device, screw compressors need to be repaired over time. This equipment contains complex mechanisms and various configurations.
Quite often, electronics fail in such a device. Compressor units have complex electronic systems that can burn out. Therefore, it is necessary to repair it, and in more difficult cases, replace it. This can be done by highly qualified professionals. The cost of the control unit is quite high. If it has a dryer, the repair of screw compressors will be even more expensive, 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 characteristics. Its price range ranges from 250 to 700 thousand rubles.
Reviews
Many users of screw compressors note the high performance of the equipment.
Because of its small size, it can be used on various construction sites without much effort during transportation. Among the shortcomings are the high cost and complexity of the design.
