Detailed explanation of the screw air compressor unit system of the variable frequency screw air compressor manufacturer

Detailed explanation of the screw air compressor unit system of the variable frequency screw air compressor manufacturer

cooling system

There are two cooling methods for air compressors: air-cooling and water-cooling. Air-cooling and water-cooling are not good or bad, only applicable and not applicable.

◆Water cooling requires the owner company to have a cooling water system, while air cooling requires more flexible layout, but there are also requirements for good ventilation in the installation site;

◆The cooling effect in the use of water-cooled models is completely dependent on the cooling water system. If the cooling water system of the owner company operates normally, the cooling effect is very stable and reliable. Air cooling is greatly affected by the ambient temperature and the installation environment, but usually the manufacturer has considered the extreme conditions in the design, so the installation according to the requirements can also achieve a satisfactory cooling effect.

◆The water-cooled air compressor does not require electrical equipment during the cooling process, and does not occupy the energy consumption of the air compressor itself (the owner’s company’s circulating cooling water requires electricity to be another matter). The air-cooled air compressor needs to be equipped with a cooling fan, which takes up the energy consumption of the air compressor itself.

◆Water cooling has high heat exchange efficiency, small size, and is more concise and compact than air cooling. In addition, because the air cooling has a heat dissipation fan, the wind noise is greater during operation, so the noise value of the water cooling is lower than that of the air cooling machine.

The medium that the air compressor needs to be cooled is compressed air, and cooling oil (or air compressor oil, lubricating oil, and coolant). The latter is the key. It is whether the entire unit can continue to operate stably. The point is.

Air compressor oil needs to circulate indefinitely in the machine body, acting as a heat transporter, bringing the heat and other heat released by the compressed air during the main engine compression process to the cooler, which is taken away by the cold medium (wind or water) .

In engineering, almost all air-cooled air compressors use plate-fin coolers, usually air cooling and oil cooling are integrated, part of which cools the compressed air (air cooling) and the other part of the air compressor oil (oil cooling). And water-cooled almost all adopt shell-and-tube type (or tube-and-tube type), divided into oil-cooled cooler and air-cooled cooler.

The air-cooled plate-fin cooler is made of aluminum or aluminum alloy by brazing. High-temperature oil and compressed air flow in the cooler, and the heat is taken away by forced convection by the cooling fan.

Water-cooled shell-and-tube (tube-and-tube) cooler, the heating medium is high-temperature oil and compressed air, and the cold medium is cooling circulating water. Through heat exchange, the heat is taken away by the cooling water.

Oil and gas separation system

When the oil-injected screw air compressor "injects oil" to participate in the compression during the air compression process, there must be a system to separate the oil from the gas, keep the oil in the body for continuous recycling, and discharge pure compressed air. This is the role of the oil and gas separation system.

It is precisely when the separation efficiency of the oil-gas separation system reaches an acceptable level that the oil-injected screw model can be used in a wide range of applications.

The oil and gas separation system of an air compressor is mainly composed of an oil storage tank and an oil and gas separator.

Work flow: The oil and gas mixture from the exhaust port of the main engine enters the oil separation tank space. After airflow collision and gravity, most of the oil gathers in the lower part of the tank, and then enters the oil cooler for cooling. The compressed air containing a small amount of lubricating oil passes through the oil fine separator core to fully recover the lubricating oil, and flows into the low pressure part of the main engine through the throttle check valve.

Control System

The control system of the air compressor includes a logic controller, various sensors, electric control parts and other control elements. To put it vividly, the air compressor control system is the brain, cerebellum, neural network, muscles and tendons, etc. An air compressor without a control system is just a bunch of parts.

At present, there are basically two types of controllers for screw machines (there are almost no pure instruments): one type of single-chip microcomputer and one type of PLC. The former is generally produced by a special air compressor controller factory to meet the general needs of air compressor control, and the logic program cannot be changed. PLC (programmable controller) is a general industrial controller, which needs to realize the function of air compressor control through self-programming, and can also meet the unique control requirements of its own products (for air compressor manufacturers).

The sensors used in the air compressor are mainly pressure and temperature sensors. Of course, there are some parts that use differential pressure switches.

The electrical control of the motor is the main part of the air compressor control. Simply put, it is to control the air compressor unit through the on/off operation of the motor. Including various AC contactors, circuit breakers, transformers, relays, etc., the electrical control part of the main motor is generally called the "starter disk".

The application of frequency conversion technology in the industry is becoming more and more extensive. This is in addition to the control of the start and stop of the motor, another control purpose: the control of the motor speed. This part is completed by a frequency converter or an embedded frequency conversion component. Usually the start/stop of the air compressor with frequency conversion is also controlled by the frequency converter, unless it is an air compressor with an industrial/frequency conversion dual system.

In addition to electrical control, there are many mechanical controls on the air compressor, such as temperature control valves, pressure valves, and so on.

Accessories for noise reduction, shock absorption, ventilation, etc.

In the oil-injected screw air compressor unit, there are also some functional accessories, most of which are standard configurations:

On the inner wall of the air compressor cabinet, there is a sound-absorbing cotton to absorb the high frequency noise of the air compressor.

Rubber shock-absorbing cushions are arranged at locations where vibrations are likely to occur in the motor, main engine, oil and gas barrels, etc.

In larger models, in addition to the cooling system, a ventilation fan is generally used for heat dissipation inside the chassis.

The air-water separator is installed in the air-cooled or integrated air-cooling system on larger models.