How to design pressure relief valve in the fire protection system? A, pressure relief valve set on fire pump outlet pipe, normally closed, open automatically in the fire service pipe pressure exceeds the set value, in order to prevent the water supply system damage due to overpressure. Second, why the overpressure fire service pipe overpressure is mainly due to the following reasons: (1) according to the fire control design flow to choose the pump flow, head curve type belongs to the steep ( Ordinary fire pump the firemen's tangent pump) , in the small flow runtime ( Self-inspection or fire early) There will be a overpressure; (2) water pump for (suddenly Such as electricity) Stalling, outlet pipe and did not take appropriate technical measures, stop the pump water hammer caused by overpressure. Three, should be paid attention to design details relief valve setting position, choice of caliber, pressure setting configuration problems and the corresponding accessories. (1) pressure relief valve can be installed at or near fire pump near fire water tank. Drain connected to the fire pool. When the pressure relief valve set on fire pump outlet pipe, in before the check valve can eliminate the pump running small flow caused by overpressure, in after the check valve ( Along the flow direction) Not only can eliminate of overpressure caused by small water pump flow of operation, also can eliminate overpressure caused by stopped pumping water hammer, even if the fire pump outlet pipe not to take other measures to eliminate stop pump water hammer ( Speed closed check valve, slow close check valve, buffer tank, etc. ) And does not cause harm and loss. Adopted in national standard atlas is installed in the pump set on the size of water supply main pipe. Specific reference to 04 s204p9. (2) there are two kinds of pressure relief valve diameter, one kind is with fire water main diameter or smaller level, another is to use DN100 or 6 pressure relief Industrial Valves. From the perspective of pressure, the greater the diameter of pressure relief valve pressure relief the faster, the better the results. But look from economic Angle, diameter, the greater the pressure relief valve, the higher the price, and from set out actually, the proposal USES fixed diameter pressure relief valve, even if the pressure when the actual pressure value will be slightly greater than the large diameter pressure relief valve pressure relief of the actual pressure value, but the comprehensive effect is feasible. As a result, the pressure relief Industrial Valves diameter according to the following options: 150 mm or less, if the fire water supply main pipe diameter D, the use of the DN100 relief valve; If the fire water supply main pipe diameter D > 150 mm, 6 is adopted at the relief valve. (3) the pressure setting of the relief valve should be higher than the main fire pump and the pressure setting of the voltage stabilizing pump. When a voltage stabilizing pump, startup and shutdown voltage stabilizing pump there are two pressure values ( The point at which the voltage stabilizing pump running pressure value) 。 Voltage stabilizing pump stopped pumping water hammer pressure is easy to cause the pressure relief valve opened by mistake, so the steady high-pressure fire fighting water supply system should be perfect and reliable technical measures to eliminate stop pump water hammer, and should review the fire service pipe residual stress after water hammer produced, if less than the pressure setting of the relief valve, to ensure that does not open by mistake. Generally higher than the pressure of 5 ~ 10 meters. (4) pressure relief valve should be installed in the branch pipe connected to the fire water main. ( Specific reference to 04 s204p9. ) For the convenience of relief valve repair and prevent the valve closed, the pressure relief valve should be set before the signal butterfly Industrial Valves gate or signal.
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