Issue of consistent diameter in the inlet and outlet pipes of the safety valve
Thread Content
When calculating the safety valve, a throat diameter of DN25 meets the discharge requirements; however, in practice a throat diameter of DN32 is used, with both the inlet and outlet pipe diameters being DN50. The safety valve is of the full-opening type. Is it reasonable to choose a throat diameter that is one size larger, while keeping the inlet and outlet pipe diameters the same?
The selection of the outlet pipe diameter must take into account the operating back pressure of the safety valve; this value should be less than 10% of the set pressure (gauge pressure) of the safety valve. For more details, refer to HG/T20570
Unreasonable. The valve needs to be redesigned due to inconsistencies with the structural dimensions of conventional safety valves.
It is reasonable that, according to TSG 21-2016 Regulations on Safety Technical Inspection of Fixed Pressure Vessels, the cross-sectional area of the connecting pipes and fittings between the pressure vessel and the overpressure relief device must not be smaller than the cross-sectional area of the inlet of the overpressure relief device. It’s because the safety valve you chose is too large, which may cause shaking or frequent pulsing.