What is a safety valve

Safety valve in the system to play the role of security. When the system pressure exceeds the set value, the safety valve open, part of the system in the gas / fluid / pipeline into the atmosphere, the system pressure does not exceed the allowable value, thus ensuring the system is not an accident due to excessive pressure.

1 nominal pressure: the maximum allowable pressure of the safety valve in normal temperature, high temperature equipment with the safety valve should not be considered under the high temperature material allowable stress reduction. Safety valve is designed and manufactured according to the nominal pressure.

2 opening pressure: also called the rated pressure or setting pressure relief valve is the valve began to rise in the operating conditions when the inlet pressure, the pressure began to measure the opening height, the media was by continuous emission state of visual or auditory perception.

3 discharge pressure: the valve flap to achieve the required opening height of the inlet pressure. The upper limit of the discharge pressure should be subject to the requirements of the relevant national standards or norms.

4 more than the pressure: the pressure of the discharge pressure and the pressure of the opening, usually expressed as a percentage of the opening pressure.

5 back seat pressure: after the release of the valve and the valve seat contact, that is, when the height of the opening into zero pressure.

6 opening and closing pressure differential: open pressure and return pressure difference, usually with the back seat pressure and the percentage of open pressure, only when the open pressure is low, the two pressure gauge to indicate.

7 back pressure: safety valve outlet pressure.

8 rated discharge pressure: the upper limit of the standard discharge pressure.

9 seal test pressure: the inlet pressure of the seal test, the leakage rate of the sealing surface of the sealing surface is measured under the pressure.

10 opening height: the actual lift of the valve position to the closed position.

11 flow channel area: refers to the valve flap inlet end to close parts of the sealing surface between the minimum cross-sectional area, used to calculate the theoretical displacement without any resistance effect.

12 runner diameter: corresponding to the diameter of the flow channel area.

13 curtain area: when the disc valve seat at the top, in the formation of the sealing surface between the cylindrical surface or conical surface area.

14 discharge area: the minimum cross-sectional area of the fluid channel when the valve is discharged. For the full revelation of the safety valve, the discharge area is equal to the flow passage area; for the micro Kai type safety valve, the discharge area is equal to the curtain area.

15 theoretical displacement: is the flow channel cross-sectional area and the safety valve flow channel area equal to the calculation of the ideal nozzle displacement.

16 displacement coefficient: the actual displacement and theoretical displacement ratio.

17 rated displacement coefficient: displacement coefficient and reduction factor (0.9) of the product.

18 rated displacement: refers to the actual displacement of the safety valve can be used as a reference to the part of the benchmark.

19 equivalent calculated displacement: refers to the pressure, temperature, medium properties and other conditions of the same conditions with the rated displacement, the calculation of the safety valve displacement.

20 frequency hopping: the safety valve valve valve is rapidly moving back and forth, in the movement of the valve seat contact.

21 flutter: the safety valve of the valve is rapidly moving back and forth abnormal movement, in the movement of the valve does not contact the valve seat.
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