Calculation of Check Valve

Selection and Calculation of Check Valves

The type and size of a check valve is selected based on the diameter of the pipeline on which it is installed. When selecting, it should be taken into account that due to the maintenance of the valve in the open position, check valves create significant hydraulic resistance.

Calculation of check valves is carried out to determine the pressure losses at the nominal water flow rate. The pressure losses in the check valve are calculated based on its flow capacity (Kvs). The value of Kvs corresponds to the volumetric flow rate of water through a fully open check valve, at which the pressure losses in the valve are equal to 1 bar.

When selecting a check valve, the values of the nominal pressure and the allowable temperature range of the transported medium should be taken into account. The maximum working pressure at the check valve installation point should be lower than its nominal pressure PN at the maximum temperature for this pressure.

It should be remembered that the nominal pressure specified in the characteristics of the valve is determined at a water temperature of 20°C, and at higher temperatures, the nominal pressure value decreases. Therefore, operation of check valves is not allowed in a mode where both the pressure and temperature of the working medium correspond to the values of the nominal pressure and maximum temperature.

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