Atlas Copco air compressor pressure valve cover plate main functions
Sealing and pressure bearing: It is sealed with the valve body through sealing elements (such as gaskets, O-rings), forming a closed cavity that can withstand the pressure of compressed air (usually consistent with the system working pressure, 0.7~1.6 MPa), preventing gas leakage.
Protecting internal components: It covers and protects the internal components of the pressure valve (such as valve cores, springs, diaphragms, etc.) to prevent dust, oil, and other impurities from entering and affecting the sensitivity of the valve.
Fixation and positioning: It is fixed to the valve body with bolts to ensure that the internal components (such as springs, valve cores) are in the correct position, guaranteeing the accuracy of the pressure valve's operation.
Pressure transmission assistance: Some cover plates are designed with pressure sensing holes or channels, which can transfer the system pressure to the diaphragm or piston inside the valve, assisting in the realization of pressure regulation functions.
Common structures and features
Structural composition:
Main body: Mostly made of metal sheets (such as cast iron, aluminum alloy, carbon steel) through stamping or casting, with a certain thickness (usually 3~10mm) to ensure the pressure-bearing capacity.
Connection holes: Multiple bolt holes are distributed circumferentially for fixation with the valve body; the center may have an observation hole (with a transparent cover) or a pressure interface.
Sealing groove: The joint surface between the cover plate and the valve body usually has a ring-shaped sealing groove for installing gaskets or O-rings.
Classification (by corresponding pressure valve type):
Pressure maintaining valve cover plate: Installed on the pressure maintaining valve at the outlet of the oil-gas separator, it withstands the internal pressure of the separator to ensure that the system establishes sufficient pressure before allowing compressed air to be output.
Unloading valve cover plate: Used to control the loading/unloading of the air compressor, the cover plate needs to cooperate with a diaphragm or piston to transmit pressure signals and achieve the opening and closing of the valve.
Safety valve cover plate: Protects the spring and valve core inside the safety valve to ensure that the safety valve can reliably jump and relieve pressure when overpressure occurs.
Key parameters and materials
Core parameters:
Dimensions: Outer diameter, the diameter of the bolt hole distribution circle, and the size of the sealing groove need to be fully matched with the valve body to ensure the installation sealingity.
Pressure-bearing capacity: It needs to meet the working pressure of the corresponding pressure valve (such as the safety valve cover plate needs to withstand more than 1.1~1.2 times the system rated pressure).
Surface accuracy: The flatness and roughness of the joint surface need to meet the standards (usually the flatness ≤ 0.1mm/m, roughness Ra ≤ 3.2μm), avoiding leakage due to poor adhesion.
Common materials:
Cast iron (HT250): Low cost, good rigidity, suitable for low pressure (≤1MPa), non-corrosive environments.
Aluminum alloy (ADC12): Light weight, corrosion-resistant, often used in medium-sized air compressors' pressure valves.
Carbon steel (Q235 or 45# steel): High strength, suitable for high-pressure (>1MPa) pressure valves, some need galvanization or painting for rust prevention.
