The actual working condition of air compressor varies with the need of process or gas consuming equipment, so that the method of selecting air compressor according to the maximum volume flow required by the device or system is not suitable. When the consumption of gas is less than that of the air compressor, the air volume adjustment of the air compressor is needed, so that the volume of the air compressor can meet the demand of gas consumption and maintain the pressure of the pipe network stable.
1. pressure opening valve regulation
According to the length of the pressure process of the intake valve, the method classifying the full stroke pressure opening valve and the partial stroke pressure opening valve in two ways. For the whole stroke, the intake valve is regulated. During the suction process, the gas is sucked into the cylinder. During the compression process, the intake gas is fully opened and the inhaled gas is all pushed out of the cylinder. An air compressor has a level of double acting cylinder, if only the top side of the intake valve piston, the gas is reduced by 50%, if both sides are open top, exhaust volume is zero, so the machine can realize the volume 0, three grade 50% and 100% regulation. It can be seen that the adjustment range of the full stroke pressure opening valve is large, which is suitable for coarse adjustment. The principle of partial stroke pressure inlet valve adjustment and full stroke pressure inlet valve is similar, but it by closing the intake valve timing control of air compressor in the process, control the number of return air, which can achieve the continuous adjustment of gas, due to compression power and exhaust almost is proportional to the quantity to reduce, so there are very high economic operation
2. speed regulation
The speed regulation is to adjust the exhaust volume by changing the speed of the air compressor. The advantages of this regulation is smaller than the power consumption of continuous gas, air compressor, air compressor pressure ratio unchanged, without a special adjustment mechanism; but it is only widely used in driving air compressor for an internal combustion engine and the turbine, if the driving machine for a motor, you will need to configure the inverter with high power high voltage inverter, expensive, and require a lot of maintenance and repair work, therefore, rarely used the method of reciprocating air compressor in the motor drive on. In addition, variable speed regulation may have adverse effects on the work of air compressors, such as flutter of valve, wear of components, increase of vibration and inadequate lubrication, which also limits the wide application of this method.
3. bypass adjustment
The exhaust pipe is connected to the intake pipe through the bypass line and the bypass valve. As long as the bypass valve is opened, some of the exhaust will return to the intake pipe. This adjustment method is flexible and simple, with automatic control system to regulate the accuracy is relatively high, but because of the excess gas compression work are all lost, so the economy is poor, therefore, this method is suitable for occasional regulation or small adjustable range occasions.
4. clearance cavity regulation
On the cylinder of the air compressor, there is not any cavity in addition to the fixed clearance volume. When it is adjusted, it is connected to the cylinder working chamber to increase the volume of the gap, reduce the volume coefficient and reduce the exhaust volume, which is the working principle of the clearance cavity adjustment. According to the different ways of access to the subsidized volume, it is divided into continuous, graded and discontinuous adjustment, which is mostly used in large process air compressor. The main drawback of this regulation is that it is usually manually adjusted, and the response speed is slow, and it is generally required to be used in conjunction with other adjustment methods. Although the way of connecting variable allowance gap volume can achieve the regulation within 0% 100% range in principle, but the system reliability is poor, and the vulnerable parts are much more difficult to maintain.