What Is The Function Of The Minimum Pressure Valve Of The Air Compressor?
May 26, 2025
The minimum pressure valve of the air compressor is a mechanical structure (including valve body, valve core, seals and other components) adjusted by a spring. It automatically opens and closes according to the system pressure: when the pressure is lower than the set value, it closes to maintain the pressure, and when the threshold is reached, it opens to output gas.
The minimum pressure valve is generally located above the oil-gas separation barrel, and the opening pressure is generally set at about 4 bar. Its main functions are reflected in the following three aspects: first, to ensure that the pressure in the oil cylinder is not lower than this minimum pressure when outputting air, so as to avoid reducing the separation effect of the oil-gas separator due to excessive air flow. Second, when the machine is started, a certain pressure is established in the oil cylinder to ensure the circulation of lubricating oil and provide the initial control pressure for the control circuit. Finally, the minimum pressure valve also acts as a one-way valve to prevent the compressed air in the air tank from flowing back to the air compressor when the unit is unloaded.
The core function of the minimum pressure valve of the air compressor is to maintain the stability of the system pressure, ensure the lubrication cycle, prevent gas backflow, and protect the oil-gas separation effect. The valve controls the pressure threshold to ensure the safety and efficiency of the air compressor under different working conditions such as startup, operation and shutdown.
Maintaining the minimum system pressure
When the air compressor is started, the oil pressure is quickly established (usually set to about 4 bar) to ensure the normal operation of the lubricating oil circulation and control system.
When the gas consumption exceeds the compressor output, the system pressure is prevented from being too low, resulting in failure of oil-gas separation, and the lubricating oil is prevented from flowing back from the separator to the main unit.
Preventing gas backflow
When the machine is stopped or unloaded, the compressed air in the air tank or pipeline is prevented from flowing back to the oil-gas separator or the main unit to avoid component damage and energy waste.
Protecting the lubrication system
By maintaining the basic pressure in the oil cylinder, the lubricating oil is ensured to circulate continuously under no-load conditions, reducing component wear.
Controlling the internal pressure of the oil-gas separator, reducing the probability of oil foam formation, and improving compression efficiency.
Buffering and protection function
Buffering the pressure difference on both sides of the oil-gas separation filter element at the moment of compressor loading to prevent high-speed airflow from destroying the separation effect or damaging the filter element material.
