Pipeline ancillaries Disc, split disc and wafer check valves
10
Kv values DN
15
20
25
40
50
80
100
For conversion: Cv (UK) = Kv x 0.963 Cv (US) = Kv x 1.156
Kv
4.4
7.5
12
26
39
84
150
Opening pressures in mbar Differential pressures with zero flow for standard and high temperature springs. Flow direction
15 (½")
20 (¾")
25 (1")
40 (1½")
50 (2")
80 (3")
100 (4")
DN
25 (0.36 psi) 22.5 (0.33 psi) 20 (0.29 psi)
25 (0.36 psi) 22.5 (0.33 psi) 20 (0.29 psi)
25 (0.36 psi) 22.5 (0.33 psi) 20 (0.29 psi)
28 (0.41 psi) 24 (0.35 psi) 20 (0.29 psi)
29 (0.42 psi) 24.5 (0.36 psi) 20 (0.29 psi)
31 (0.45 psi) 25.5 (0.37 psi) 20 (0.29 psi)
33 (0.48 psi) 26.5 (0.38 psi) 20 (0.29 psi)
Where lowest opening pressures are required, valves without springs can be installed in vertical pipes with bottom-to-top flow. Without spring 2.5 (0.036 psi) 2.5 (0.036 psi) 2.5 (0.036 psi) 4.0 (0.058 psi) 4.5 (0.065 psi) 5.5 (0.080 psi) 6.5 (0.094 psi)
Pressure loss diagram
0.725 1.45 2.90 Pressure loss in psi
0.145 0.290
7.25 14.5
7.5.13
10.5 18
Pressure loss in bar
Pressure loss diagram with open valve at 20 °C (68 °F). The values indicated are applicable to spring loaded valves with horizontal flow. With vertical flow, insignificant deviations occur only within the range of partial opening. The curves given in the chart are valid for water at 20 °C (68 °F). To determine the pressure for other fluids the equivalent water volume flowrate must be calculated and used in the graph.
Vw = Equivalent water volume flow in l/s or m³/h = Density of fluid kg/m³ V = Volume of fluid l/s or m³/h Vw = 1000 x V
Where:
Pressure loss information for steam, compressed air and gases is available from Spirax Sarco.
TI-P134-04 CMGT Issue 16
Page 4 of 5
DCV4 Disc Check Valve
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