The minimum pressure valve is composed of valve body, valve core, spring, sealing ring, adjusting screw, etc. It is installed at the outlet of the oil separator. Its function is to keep the pressure in the oil separation tank from falling below 0.4MPa. The compressed air containing oil can be separated better in the separator and the loss of lubricating oil can be reduced. At the same time, it can ensure the gas pressure required to establish the oil pressure. The minimum pressure valve also functions as a one-way valve to prevent the compressed air in the system from flowing back when the system is shut down. The holding pressure of the minimum pressure valve has been adjusted before leaving the factory. If the holding pressure changes due to a long time of use, it can be adjusted by the adjustment screw on the valve.

Minimum pressure valve action:

1.Priority is given to establishing the circulating pressure required by the lubricating oil at startup to ensure the lubrication of the machine.

2.The oil and gas barrels can be opened only after the gas pressure exceeds 0.45MPa, which can reduce the air flow rate through the oil and gas separator. In addition to ensuring the effect of the oil and gas separator, it can also protect the oil and gas separator from damage due to excessive pressure difference.

3.Non-return function: When the pressure in the oil and gas barrel drops after shutdown, it prevents the pipeline compressed air from returning.

Common malfunctions:

There are many compressor failures caused by the minimum pressure valve, mainly as follows: the cylinder safety valve jets during operation, this failure is because the minimum pressure valve is not opened, resulting in excessive pressure, safety valve pressure relief protection; motor during operation Overload protection, because the minimum pressure valve is not opened, the pressure is too high, the motor is overloaded, and the thermal relay protects the shutdown; the compressor fails to start, and the minimum pressure valve is not closed tightly, resulting in the return of compressed air in the pipe network, and the startup failure under pressure; when unloading The oil pressure is high and the energy consumption increases. Because the minimum pressure valve is not tightly closed, the compressed air of the pipe network returns when the unit is unloaded, which causes the pressure in the compression chamber to rise and the oil pressure rises.

The reasons that cause the minimum pressure valve to close tightly, damage, and fail are: poor air quality or external impurities entering the unit, impurity particles driven by the high-pressure airflow, impact the minimum pressure valve, causing damage to the minimum pressure valve components, or Dirt is trapped between the sealing surfaces, causing the minimum pressure valve to fail; the compressor is filled with too much oil, and too much lubricating oil will form oil viscosity in the minimum pressure valve, causing the valve plate to close or open; the minimum pressure valve is based on a specific Depending on the design of the working conditions, if the working conditions fluctuate greatly or deviate from the design value for a long time, the minimum pressure valve will quickly fail; when the compressor is stopped for a long time and then turned on again, the moisture contained in the lubricating oil and air is inside the equipment unit Accumulate, corrode various parts of the minimum pressure valve, and form oil viscosity.