The safety valve of an air compressor is a type of automatic valve. Its working principle is as follows: when the pressure of the medium inside the air compressor or pipeline rises above the specified value, it discharges the medium out of the system to prevent the medium pressure in the pipeline or equipment from exceeding the set limit. By controlling the pressure within the specified range, it plays a crucial protective role in ensuring the safe operation of the air compressor and personal safety. In accordance with the Safety Technical Supervision Regulation for Safety Valves, safety valves shall undergo periodic calibration at least once a year, with corresponding provisions specified in the safety technical codes.

How to Test Air Compressor Safety Valves?

1、Offline calibration on a test benchMount the safety valve on a dedicated test bench, then use a calibration medium to open the valve, and confirm the opening pressure by observing the pressure gauge. However, this method is not applicable for calibrating back pressure safety valves or those used with high/low temperature media.

2、Online calibration with dedicated instrumentsMeasure the downward spring force acting on the safety valve by external force, and calculate the valve's opening pressure based on the measured value. This method generally does not affect production or require changing the system pressure; it features relatively fast testing speed and ease of operation, but cannot detect the sealing performance of the safety valve.

3、Pressure-rising pop-off calibrationInstall the safety valve in the actual system, then manually increase the system pressure until the valve pops off, and observe its opening pressure during the process. This calibration method causes relatively severe damage to the valve's sealing surface and poses a higher operational risk compared with the other two methods.

Operating Precautions for Air Compressor Safety Valves

A safety valve is not suitable for use in the following scenarios:

1、When the pressure rises rapidly and the valve's discharge rate is lower than the pressure rise rate.

2、When strict requirements are imposed on sealing performance.

3、When the materials inside the vessel may cause the safety valve to fail (e.g., the vessel contains a large amount of solid particles, which will lead to poor sealing after the valve reseats).

4、When the materials inside the vessel are highly toxic or possess other properties that may endanger public safety.