The function and basic performance of compressed air filter pressure reducing valves

2023-03-21

Filters, pressure reducing valves, and lubricators together form the pneumatic trio. The filter is mainly responsible for filtering liquid water, oil, and impurities from compressed air. The pressure reducing valve is primarily used to control system pressure, while the lubricator is responsible for supplying oil lubrication to downstream components. Generally, lubricators are not used much nowadays because many products can achieve oil-free lubrication, eliminating the need for lubricators.

The function of a compressed air filter: to remove solid impurities, water droplets, and oil droplets from compressed air, but it cannot remove gaseous oil and water.

Based on the drainage method of the filter, there are manual drainage types. Automatic drainage types can be further categorized into normally open and normally closed types based on their drainage state when there is no air pressure.

The function of a pressure reducing valve: A pressure reducing valve is an intelligent valve that uses the medium's own energy to regulate and control pipeline pressure. By adjusting the pilot valve of the pressure reducing valve, the outlet pressure of the main valve can be regulated. The outlet pressure remains unaffected by changes in inlet pressure or inlet flow, reliably maintaining the set outlet pressure. The set value can be adjusted as needed to achieve the purpose of pressure reduction.

Basic performance of pressure reducing valves:

(1) Pressure regulation range: This refers to the adjustable range of the output pressure P2 of the pressure reducing valve, within which the specified accuracy must be achieved. The pressure regulation range is mainly related to the stiffness of the pressure regulating spring.

(2) Pressure characteristics: This refers to the characteristic where, at a constant flow rate g, output pressure fluctuations occur due to input pressure fluctuations. The smaller the output pressure fluctuations, the better the performance of the pressure reducing valve. The output pressure must be below the input pressure by a certain value to remain largely unaffected by changes in input pressure.

(3) Flow characteristics: This refers to the characteristic where, at a constant input pressure, the output pressure changes with variations in output flow g. The smaller the change in output pressure when flow g varies, the better. Generally, the lower the output pressure, the smaller the fluctuations caused by changes in output flow.