First of all, you need to understand what the Dewar’s Bottle Safety Valve Release Pressure is, and what the back pressure of the safety valve is. Dewar’s bottle safety valve release pressure is when the valve flap open height when the pressure of the inlet side. Return pressure for the safety valve release, the valve flap re-pressure valve seat, the medium in the stop discharge pressure. The following is an explanation of the safety valve discharge pressure and return pressure is how to adjust, as well as the relevant precautions.

How to adjust the Dewar’s bottle safety valve vent and back pressure?

1. Before installing the safety valve, pressure resistance test and gas tightness test should be carried out to check the strength and sealing performance of the safety valve, and then calibrated and adjusted.

2. On a gas test bench, adjust the opening pressure of the safety valve and the load applied to the control valve flap. Handle safety valve can adjust the position of the weight, spring-type safety valve to adjust the spring compression. Safety valve opening pressure should be consistent with the boiler. Pressure vessel safety technology supervision regulations of the relevant provisions.

3. on the vessel, by adjusting the safety valve adjusting ring and valve flap clearance to adjust the safety valve discharge pressure and back pressure. If the safety valve in the open pressure only leakage without jumping, or although jumping but after the pressure drop there are violent vibration and “beeping” sound, the gap is too large, should be adjusted smaller. If the return pressure is too low, the adjustment ring gap is too small, should be adjusted appropriately high. The pressure discharged from the safety valve used for steam should be less than or equal to 1.03 times of the opening pressure, and the pressure difference between opening and closing should not exceed 10% of the opening pressure. Safety valves for air or other gases, the discharge pressure should be less than or equal to 1.10 times the opening pressure, the opening and closing pressure difference should not exceed 15% of the opening pressure.

4. In the calibration and pressure adjustment, must have the use of units in charge of boiler and pressure vessel safety in the presence of technical personnel, for the adjustment and calibration device pressure gauge accuracy shall not be less than 1 level, and in the on-line commissioning to be taken in the safety protection measures.

Spring-type and lever-type safety valves need to pay attention to when adjusting the bleed pressure and seat back pressure, for the structure with a recoil plate and seat adjustment ring, the seat adjustment ring is used for adjustment. Unscrew the adjusting ring fixing screws, and extend a thin iron bar from the threaded hole exposed in the tool, then you can toggle the teeth of the wheel on the adjusting ring to rotate the adjusting ring left and right. With the counterclockwise rotation of the adjusting ring, the position of the adjusting ring rises and the discharge pressure and back pressure decrease.