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Setting pressure of safety valve
Release time:
2024-04-07
Setting pressure is also called opening pressure, is an important parameter of the safety valve operation, setting pressure setting is directly related to the safety of equipment operation.
Set pressure refers to the predetermined pressure when the safety valve disc starts to open under operating conditions. It is the gauge pressure measured at the valve inlet. At this pressure, under the specified operating conditions, the force generated by the medium pressure to open the valve is balanced with the force that keeps the valve flap on the valve. At this pressure, a measurable opening height begins, and the medium assumes a continuous discharge state that can be perceived visually or audibly.
The set pressure of the safety valve is generally not greater than the design pressure of the pressure vessel or pipeline. If there is a high allowable working pressure marked on the design drawing or nameplate, the high allowable working pressure can also be used to determine the setting pressure of the safety valve.
Within the specified working pressure range, the setting pressure can be adjusted by rotating the adjusting screw and changing the spring preload compression. Remove the valve cover and loosen the lock nut to adjust the adjusting screw. First, raise the inlet pressure to make the valve jump once. If the opening pressure is low, tighten the adjusting screw clockwise. If the opening pressure is high, loosen it counterclockwise. After adjusting to the required set pressure, tighten the lock nut and install the cover cap.
If the required setting pressure exceeds the working pressure range of the spring, it is necessary to replace another spring with a suitable working pressure range, and then adjust the corresponding data on the nameplate after replacing the spring.
When adjusting the set pressure, the following points should be noted:
(1) When the medium pressure is close to the set pressure (reaching more than 90% of the opening pressure), the screw should not be rotated to prevent the valve flap from rotating and damaging the sealing surface.
(2) In order to ensure the accuracy of the setting pressure value, the medium conditions used during adjustment, such as the type of medium and the temperature of the medium, should be as close as possible to the actual working conditions. The type of medium changes, especially when the liquid phase changes to the gas phase, the set pressure often changes. When the working temperature increases, the setting pressure decreases. Therefore, when adjusted at room temperature and used at high temperature, the set pressure value at room temperature should be slightly greater than the required opening pressure value.
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