Calibration issues for directly-acting full-open safety valves with springs
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For spring-direct-acting full-open safety valves, why do some people say that \"a setting device can only determine the opening pressure; it cannot bring the safety valve to its full-open position or ensure complete discharge from the valve.\" ”? + G6 s3 M/ J9 \#What is generally the difference between the discharge pressure and the seat pressure of a pure spring-type fully open safety valve? The guidelines specify a ratio of 1.03, but in practice, does anyone know what it is? Has the discharge pressure been calibrated? How was it calibrated?
There are regulatory requirements regarding the difference in discharge pressures, and the requirements vary for boilers operating at different pressure levels. For example, for pressures of 9.8 MPa, it is generally required that the superheater operate at 1.05 times that pressure, while the drum should operate at 1.08 times that pressure. After the safety valves are installed, thermal testing is carried out to verify their opening and closing pressures