The minimum pressure valve of the screw air compressor is also called the pressure maintenance valve. It is composed of valve body, valve core, spring, sealing ring, adjusting screw, etc. The inlet end of the minimum pressure valve is generally connected to the air outlet of the oil and gas cylinder, and the air outlet is generally connected to the inlet end of the cooler.
The function of the minimum pressure valve
1. The minimum pressure valve is mainly used to establish the internal pressure of the unit, promote the circulation of lubricating oil, and meet the working pressure of the unloading valve. The oil lubrication of the machine is carried out by the pressure difference of the machine itself, without additional oil pump assistance. When the machine is in the start-up and no-load state, a certain pressure is required to maintain the oil circulation. The minimum pressure valve can keep the pressure in the oil separation tank from dropping below 4Bar , When starting, give priority to establishing the circulation pressure required by the lubricating oil to ensure that the machine is lubricated and the loading valve can be opened.
2. Protect the oil separation element. When the pressure exceeds 4bar, it will open to reduce the air velocity flowing through the oil and gas separator. In addition to ensuring the oil and gas separation effect, it can also protect the oil and gas separation filter element from being damaged due to a large pressure difference. Reduces impact on the separator core when the machine is loaded.
3. The minimum pressure valve acts as a one-way valve to prevent the compressed air in the system from flowing back into the machine when the machine is shut down.
Common fault analysis
1. The air compressor equipment is composed of many valve parts. The air medium is not good or external impurities enter the unit. Driven by high-pressure airflow, impurity particles impact the minimum pressure valve, resulting in damage to the minimum pressure valve parts; or dirt is caught between the sealing surfaces, resulting in failure of the minimum pressure valve.
2. If the medium is filled with liquid or the gas-liquid separator of the compressor fails, it will cause liquid shock to the minimum pressure valve, and the minimum pressure valve will accelerate to failure due to the additional impact, which is mainly manifested by abnormal sound when the compressor is running.
3. If too much oil is injected into the air compressor, too much lubricating oil will form oil stickiness in the minimum pressure valve, causing the valve plate to be delayed in closing or opening and breaking.
4. The minimum pressure valve is designed according to specific working conditions. If the working conditions fluctuate greatly and deviate from the design value for a long time, the minimum pressure valve will fail quickly.
5. When the air compressor is stopped for a long time and then restarted, the moisture contained in the lubricating oil and air will accumulate inside the equipment unit, which will not only corrode the parts of the minimum pressure valve, but also start the operation with moisture, which will easily cause liquid shock , oil sticky.
6.Various factors such as unit resonance, improper operation, and environment will affect the life of the minimum pressure valve of the compressor.
Post time: May-29-2023
