The main purpose of safety valve calibration is to calibrate the safety valve. The safety valve can be calibrated by: off-line calibration of the calibration table, that is, installing the safety valve on the calibration table, then opening the safety valve with the calibration medium, and confirming the opening pressure by observing the pressure gauge. Step-up jump method: install a safety valve in the system, and the system artificially raises the pressure until the safety valve jumps to observe the opening pressure of the safety valve. This verification method has great damage to the sealing surface of the safety valve and great operational risk.
On-line instrument calibration:
It measures the downward spring force acting on the safety valve by external force, and then calculates the opening pressure of the safety valve. This method generally does not affect the production and does not need to change the system pressure, and the detection speed is relatively fast and convenient, but this method cannot detect the sealing performance of the safety valve.
Operational requirements:
When the safety valve is calibrated online, the production system should be in a normal and stable state; The monitoring of various operating parameters of online calibration system should be strengthened, and the operators should cooperate closely at the scene. When signs of deviation from normal operation are found, calibration should be stopped immediately and measures should be taken in time to ensure the safety of the device. Records shall be kept during online calibration of safety valves. Online calibration should be carried out by trained and qualified personnel.
The qualifications of maintenance personnel are divided into Grade I and Grade II:
The first-level maintenance personnel can engage in the maintenance, overhaul and calibration of spring-type safety valves, lever-type safety valves and self-weight (heavy hammer) safety valves; Calibration can be performed on the calibration table. Secondary maintenance personnel can engage in the maintenance, overhaul and calibration of various safety valves. Calibration can be done on the calibration table, and pressure setting can also be done online.