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Air compressor: Screw air compressor frequency conversion energy saving transformation principle and application


Air compressor: screw air compressor is widely used in industrial production. The loading and unloading valve is used to control the air supply of air compressor. Because the gas consumption of gas equipment fluctuates greatly, the different working cycle or production process sometimes causes frequent loading and unloading of air compressors. After the air compressor is unloaded, the motor still runs at power frequency, which not only increases the mechanical wear of the equipment, but also wastes electric energy. The loading process of air compressor is sudden loading, which will also have a great impact on equipment and power grid. Therefore, frequency conversion transformation of air compressor can reduce mechanical wear of equipment, change the starting and running mode of motor, and save electric energy in a certain range.

The working principle of screw air compressor: the working process of screw air compressor is divided into four processes: inhalation, sealing and transportation, compression and discharge. The screw meshes with the grooves of the shell. When the screw rotates in the shell, the air is inhaled from the air inlet and the oil is sucked at the same time. The oil and gas inhaled is sealed and transported to the exhaust port due to the rotation of the meshing surface of the grooves; During transportation, the meshing clearance of the grooves gradually decreases and the oil and gas is compressed. When the meshing surface of the cogs rotates to the exhaust port of the housing, the oil and gas mixture with higher pressure is discharged from the engine body.

In factory air compressor control systems, pressure relays installed in rear ducts are widely used to control the operation of air compressors. When the air compressor is started, the loading valve does not work, the loading cylinder does not act, the air inlet of the air compressor head is closed, and the motor is started without load. If the gas consumption of the back-end equipment is large, when the air compressor starts to run, the compressed air pressure in the air storage tank and the back-end pipeline does not reach the upper limit of pressure, open the air inlet, the controller acts as the loading valve, the motor runs with load, and the compressed air is constantly generated in the back-end pipeline. If the back end equipment stops using gas, the pressure of compressed gas in the back end piping and storage tank will gradually increase. The pressure controller sends out unloading signal, when the pressure reaches the upper limit, the loading valve stops working, the air inlet is closed, and the motor runs without load.

Notes for screw air compressor frequency conversion transformation: When frequency conversion transformation, attention should be paid to maintaining the integrity of the main loop and control loop of the original equipment as far as possible, and the less the loop changes, the better; This is conducive to the air compressor in the frequency converter failure or overhaul, can easily change back to the original control mode, to ensure that the air compressor can run under the condition of frequency conversion and power frequency, but also makes the transformation without rewriting the PLC program.

Screw air compressor inverter failure, can be directly switched to the power frequency operation mode, does not affect the production. The start signal of the converter is controlled by the angular AC contactor KM1, which means that the converter does not start and there is no output when the star is formed. The setting time of time relay JS should be greater than or equal to the start time of the frequency converter to ensure the no-load frequency conversion start of the frequency converter and avoid overload trip when the frequency converter starts at low frequency.

Shijiazhuang Compus Compressor Co., Ltd. main products are oil-free air compressor, high pressure air compressor, screw air compressor, air compressor, drilling air compressor, oil-free mobile machine, high pressure mobile machine, drilling machine, two-stage compression screw machine, permanent magnet variable frequency screw machine, mine explosion-proof screw machine, air floating centrifugal blower and so on. At present, the company has established 30 customer service networks and more than 100 dealers in the country, to provide customers with pre-sales technical consultation, machine sales, on-site maintenance, parts supply 4S services. The enterprise's good faith service is well received by users. Adhering to the core concept of "quality first, customer satisfaction", we always adhere to provide customers with high-quality products and technical services, we firmly believe that Compus will become your more reliable partner, and are willing to work with you to achieve glory!