The main types and functions of the regulating valves for Atlas Copco air compressors
Pressure Regulator
Function: Reduce the high-pressure compressed air output by the air compressor to the stable pressure required by the downstream equipment, and maintain the output pressure constant when the intake pressure fluctuates.
Application location: Usually installed at the outlet of the storage tank or before the post-treatment equipment such as dryers and filters to protect the downstream pneumatic equipment from overpressure damage.
Features: Equipped with a pressure setting knob, allowing the output pressure to be adjusted according to requirements, and with built-in overflow or pressure reduction structures to maintain pressure stability.
Intake Valve
Function: Control the air volume entering the main unit of the air compressor, being the core component for regulating the exhaust volume, and cooperating with the control system to achieve loading/unloading or frequency conversion regulation of the unit.
Application location: Installed between the air filter and the intake port of the main unit, commonly found in screw-type air compressors.
Working principle:
Loading: The valve is fully open, allowing the maximum amount of air to enter the main unit for compression.
Unloading: The valve is closed (or partially closed), reducing the intake volume (even stopping the intake), lowering energy consumption.
In variable frequency models: Linked with the VSD system, the opening degree is adjusted continuously to match the gas consumption.
Minimum Pressure Valve
Function: Ensure that the minimum pressure (usually 4-5 bar) is maintained in the oil-gas separator to ensure the smooth circulation of lubricating oil (pushed into the main unit by the pressure difference), and prevent reverse flow of compressed air during shutdown.
Application location: Installed between the outlet of the oil-gas separator and the main exhaust pipeline, a necessary safety component for screw-type air compressors.
Thermostatic Valve
Function: Regulate the cooling path of the lubricating oil to ensure the oil temperature remains within the optimal range (usually 80-95℃), avoiding emulsification of the lubricating oil at low temperatures or deterioration of the oil at high temperatures.
Working principle: During low temperatures, the bypass cooler is used, allowing hot oil to directly enter the main unit; as the temperature rises, it gradually opens to guide hot oil into the cooler for cooling. Technical features
High-precision control: Utilizing precise valve cores, diaphragms or pistons, the control accuracy is high (pressure control deviation is usually ≤ ±0.2 bar).
Temperature and pressure resistance: Suitable for high-temperature (80~120℃) and high-pressure (up to 16 bar or above) environments of air compressor systems. The materials are mostly cast iron, aluminum alloy or stainless steel.
Quick response: When linked with control systems such as Elektronikon®, it can respond quickly to pressure changes (at the millisecond level), ensuring system stability.
Low leakage design: The leakage is extremely small in the closed state, reducing energy waste, especially significantly reducing idle energy consumption in the unloaded condition.
Common faults and maintenance
Fault manifestations:
Pressure regulation failure (output pressure is too high / too low or fluctuates greatly).
Valve jamming (unable to open / close normally, resulting in loading difficulties or incomplete unloading).
Severe leakage (damage to the valve body or sealing surface, manifested as pressure drop or abnormal noise).
Failure of temperature control valve leading to abnormal oil temperature (too high or too low).
Common causes:
Wear or scaling of the valve core or valve seat (due to impurities in compressed air or accumulation of oil deposits).
Ageing or damage of seals (O-rings, diaphragms).
Spring fatigue (causing drift in pressure set value).
Abnormal control system signals (such as electromagnetic valve failure affecting valve operation).
