Air compressors are widely used in power, chemical, mining, metallurgy, refrigeration and other fields. They are mainly used to provide a continuous supply of compressed air with certain pressure, such as gas supply to pneumatic valves and gas supply to processes that require a certain pressure gas. source. There are many kinds of air compressors. Currently, screw air compressors have become the mainstream of future market demand because of their huge advantages in terms of gas volume, maintenance, energy saving, and service life. They have become the consensus in the industry and are widely used in many industries. .
Screw air compressor work process as shown below:
The traditional solution is to use a load-discharge valve to control the air supply of the air compressor. Due to the difference between the working cycle of the air equipment and the production process, the air volume fluctuates, causing the air compressor to frequently load and unload.
(1) Loading
In the loaded state, after the pressure reaches a minimum value, the original control mode determines that the pressure will continue to rise until the maximum pressure value. During the pressurization process, more heat must be released to the outside world, resulting in loss of power. On the other hand, before the gas above the pressure maximum enters the pneumatic element, its pressure needs to be decompressed through the pressure reducing valve. This process is also an energy-consuming process. And loading is an abrupt process that has a large impact on the equipment and the power grid.
(2) Uninstall
In the no-load state, when the pressure reaches the maximum pressure, the air compressor is depressurized and unloaded by closing the air intake valve to make the motor idle, and at the same time, the excess compressed air in the separation tank is vented through the vent valve. This adjustment method causes a great deal of energy waste. According to our estimation, the energy consumption of the air compressor during unloading accounts for about 10% to 25% of the full load of the air compressor, which is still a small proportion of the unloading time. In other words, about 20% of the time when the air compressor is operating is in an idle state, and it is doing no use, which not only wastes power but also increases the mechanical wear of the equipment.
Based on these traditional shortcomings, we conducted an in-depth study of the industry's processes and explored a dedicated inverter for the screw air compressor industry.
Variable frequency screw air compressor control system:
HLP-SK frequency conversion screw air compressor control system features:
1. Stable pipe network pressure: The variable frequency screw air compressor utilizes the stepless speed regulation feature of the inverter. Through the PID regulator inside the controller or inverter, the pressure can be quickly adjusted and controlled; Compared with the upper and lower limit switch control, the pressure stability is improved exponentially;
2. Better energy-saving effect: The inverter adjusts the motor speed in real time according to the actual gas consumption. When the gas consumption is low, it can start the automatic dormancy, which can effectively reduce the idle time or avoid the screw compressor from entering idle state, thus greatly reducing Loss of energy.
3, start without impact: As the inverter itself is a soft-start device, the starting current is at most twice the rated current, compared with the start of the power frequency is generally more than 6 times the rated current, the starting impact is very small. The impact on the electrical components of the motor at the moment of starting is reduced, and the life of the motor and the contactor is prolonged.
4, the noise becomes smaller: due to the reduction of the number of frequent air compressor loading and unloading, the noise is reduced accordingly
5, to improve the operating efficiency: As the compressor can not be ruled out the possibility of long-term operation under full load, so only the maximum demand to determine the capacity of the motor, so the design capacity is generally large. In actual operation, the proportion of light-load operation time is very high. Such as using frequency control can improve work efficiency.
6, improve the performance of the compressor: As the inverter can be easily adjusted continuously, to maintain the stability of pressure, flow, temperature and other parameters.
7, good compatibility: due to the use of modbus communication protocol, can be used in conjunction with most of the air compressor dedicated controller on the market.