Technical specifications of the check valve

DN - nominal diameter - a conventional designation of the size of pipeline fittings. The value of the nominal diameter is dimensionless and approximately equals the internal diameter of the opening in the check valve's connecting flanges, measured in millimeters. Nominal diameters are adopted to standardize the sizes of pipeline fittings and elements of pipeline systems.

PN - nominal pressure - this is the maximum allowable pressure of water at a temperature of 20°C, under which the check valve is allowed to operate for an extended period.

Test pressure (Ppr) - this is the pressure of water at a temperature between 5 and 70°C, at which the check valve must undergo hydraulic testing for strength and tightness.

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

Operating pressure (Pр) - this is the maximum excess pressure for each working medium temperature at which the check valve can operate for an extended period.

For most types of pipeline fittings, it is not allowed to operate at nominal pressure with the maximum allowable temperature. Therefore, as the pressure approaches nominal, the maximum working temperature decreases.

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

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