Check valve specifications

DN - nominal diameter - a conventional designation of the size of pipeline fittings. The nominal diameter has no dimension and is approximately equal to the internal diameter of the openings in the connecting flanges of the check valve, measured in millimeters. Nominal diameters are adopted to unify the sizes of pipeline fittings and elements of pipeline systems.

PN - nominal pressure - this is the maximum allowable water pressure at a temperature of 20°C, under which the check valve can operate continuously.

Ppr - test pressure - this is the water pressure at a temperature between 5 and 70°C, at which the check valve should be tested for strength and tightness.

Opening pressure of the check valve - the pressure difference between the inlet and outlet of the valve at which the disc begins to open the passage. The full opening pressure corresponds to the required pressure difference for the disc to fully open.

Pr - working pressure - this is the maximum excess pressure for each operating medium temperature at which the check valve is allowed to operate continuously.

For most types of pipeline fittings, operation at nominal pressure with the maximum allowable temperature is not permitted. Therefore, as the pressure increases to the nominal value, the maximum operating temperature decreases.

Kvs - flow coefficient - its value corresponds to the water flow in m³/h at a temperature of 20°C, at which the pressure loss through a fully open check valve is 1 bar. The flow coefficient is used in valve selection and hydraulic calculations for pipeline systems.