Technical term for safety valve
Writer： admin Time：2019-11-07 11:25 Browse：℃
Safety valve I believe you are familiar with, should know what is a kind of thing, there will be a lot of technical terms when it comes to safety valve. The following Shanghai pu shou boat valve to give you a simple introduction about the safety valve of some technical terms
Nominal pressure: represents the maximum allowable pressure of the relief valve at normal temperature. Relief valve for high-temperature equipment should not consider the reduction of allowable stress of materials at high temperature. The relief valve is designed and manufactured to nominal pressure standards.
Open pressure: also known as rated pressure or set pressure, it refers to the inlet pressure when the relief valve disc starts to rise under operating conditions. Under this pressure, it starts to have a measurable open height, and the medium is in a continuous discharge state that can be perceived by vision or hearing.
Discharge pressure: inlet pressure when the disc reaches the specified opening height. The upper limit of emission pressure shall comply with the requirements of relevant national standards or norms.
Introduction to safety valve
Excess pressure: the difference between the discharge pressure and the opening pressure, usually expressed as a percentage of the opening pressure.
Return seat pressure: disc contact with seat after discharge, that is, the inlet pressure when opening height becomes zero.
Open/close pressure difference: the difference between the opening pressure and the return pressure is usually expressed as the percentage of the return pressure and the return pressure.
Back pressure: pressure at the outlet of the relief valve.
Rated discharge pressure: the upper limit of discharge pressure specified in the standard.
Seal test pressure: inlet pressure for seal test, under which the leakage rate through the sealing surface of the closed piece is measured.
Open height: the actual lift of the disc away from the closed position.
Some terms for safety valve
Channel area: the minimum cross-sectional area of the channel between the inlet end of the disc and the sealing surface of the closed piece, used to calculate the theoretical displacement without any resistance effect.
Runner diameter: the diameter corresponding to the runner area.
Curtain area: cylindrical or conical channel area formed between the sealing faces of the valve when the disc is above the seat.
Discharge area: the minimum cross section area of the fluid passage when the valve is discharged. For a fully revealed relief valve, the discharge area is equal to the channel area; For micro-open relief valves, the discharge area is equal to the curtain area.
Theoretical displacement: it is the calculated displacement of an ideal nozzle whose cross section area is equal to that of the relief valve.
Displacement coefficient: the ratio of actual displacement to theoretical displacement.
Rated displacement coefficient: the product of displacement coefficient and reduction coefficient (take 0.9).
Rated displacement: the part of the actual displacement that is allowed as the applicable benchmark for the relief valve.
Equivalent calculated displacement: it refers to the calculated displacement of the safety valve when the conditions of pressure, temperature, medium nature and other conditions are the same as the applicable conditions of rated displacement.
Frequency hopping: the relief valve disc moves back and forth abnormally quickly, during which the disc touches the seat.
Flutter: the relief valve disc moves back and forth abnormally quickly, during which the disc does not touch the seat.