What is the working principle of screw air compressor?

Brief introduction and working principle analysis of screw air compressor

I. Overview

Air compressor is a variety of factories,

Necessary equipment for road construction, mining and construction industries,

Mainly used to provide a stable flow.

Constant pressure compressed air,

For example, supplying gas to pneumatic valve and supplying gas source to process flow that needs gas with certain pressure.

There are many air compressors.

There are many kinds, such as screw air compressor, piston air compressor, centrifugal air compressor and scroll air compressor. And the screw air compressor

Has huge market potential,

It is widely used in many industries.

The air compressor adopts loading and unloading valves to control the air in its control.

Air supply to the printing press,

Due to the difference of working cycle or production process of gas equipment, gas consumption fluctuates.

Sometimes it can lead to

Air compressors are frequently loaded and unloaded. After unloading, the air compressor still runs at power frequency, which not only wastes electric energy, but also increases the mechanical wear of the equipment.

Loading is a sudden process,

It will have a great impact on equipment and power grid.

Therefore, the frequency conversion transformation of air compressor has the following advantages.

Improve the starting and running of the motor,

Reduce the mechanical wear of equipment, and save electricity in a certain range.

This article is mainly about Taiwan Province.

Air compressor controller

CCAC-M

Yudongyuan

7200GS

Application of control system composed of frequency converter in screw air compressor.

2. Working principle of screw air compressor

Take a single screw air compressor as an example to illustrate that working principle of the air compressor,

draw

Shows the structural schematic diagram of a single screw air compressor. The working process of screw air compressor is divided into four processes: suction, sealed transportation, compression and exhaust. When the screw rotates in the shell, the screw engages with the cogging of the shell, air is sucked in from the air inlet, and engine oil is also sucked in, and the sucked oil and gas are sealed and transported to the exhaust port due to the rotation of the cogging surface; In the process of transportation, the meshing gap between teeth is getting smaller and smaller, and oil and gas are compressed. When the cogging surface rotates to the exhaust port of the shell, the oil-gas mixture with higher pressure is discharged from the shell. The frequency converter can change the displacement by changing the speed of the screw rotor. When the gas consumption changes, the frequency converter can adjust the exhaust volume of the air compressor by changing the speed, so as to keep the exhaust pressure constant and save energy.

3. Composition of air compressor system

1. In the air compressor control system, the air compressor is controlled by a pressure sensor installed on the air outlet pipe at the back end of the air compressor.

Stress. When the air compressor is started, the loading solenoid valve is closed, the loading cylinder does not move, and the inverter drives the motor to run at no load.

After a period of time (which can be arbitrarily set by the controller, set to 10S), the loading solenoid valve is opened and the air compressor runs with load. while

After the air compressor starts running, if the gas consumption of the back-end equipment is large, the pressure of compressed gas in the gas storage tank and the back-end pipeline will not reach the pressure.

At the upper limit, the controller loads the valve, opens the air inlet, and the motor runs with load to continuously generate compressed air to the back-end pipeline. such as

If the back-end gas equipment stops using gas, the pressure of compressed gas in the back-end pipeline and gas storage tank will gradually increase. When it reaches the set value of the upper pressure limit,

The pressure sensor sends an unloading signal, the loading solenoid valve stops working, the air inlet filter is closed, and the motor runs at no load.

When the air compressor runs continuously, the temperature of the compressor body will rise. When the temperature reaches a certain level, the system is set to 80℃ (which can be set by the controller according to the application environment), and the fan starts to operate to reduce the working temperature of the main engine. After the fan runs for a period of time, the temperature of the main engine drops, and the fan stops running below 75℃. Schematic diagram of air compressor system is as follows:

2. Composition and parameter setting of control system The screw machine control system adopts the special controller for Taian air compressor (CCAC-M type), and the frequency converter adopts Dongyuan 7200GS series (power section is 25HP∽400HP).