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Control systems Pressure reducing/surplussing valves
Capacities for safety valve sizing
Size
DN15 DN20 DN25
For conversions: C v (UK) = K v x 0.963 C v (US) = K v x 1.156
Full lift capacities for safety valve sizing purposes:
K v
1.5
2.5
3.0
Steam and compressed air capacities
4.6 10
Upstream pressure bar g (x 100 = kPa)
½" - DN15
Steam capacity kg/h
¾" - DN20
1" - DN25
½" - DN15
Compressed air capacity dm 3 /s* free air
¾" - DN20
1" - DN25
* dm 3 /s = I/s, 1 I/s d 2 c.f.m.
How to use the chart The curved lines labelled 2, 3, 4, 5 etc., represent upstream pressures. Downstream pressures are read along the vertical line on the left hand side of the chart. How to use the chart is best described by an example:- Required, a pressure reducing valve to pass 120 kg/h reducing from 8 to 6 bar. From the downstream pressure of 6 bar on the left hand side of the chart extend out horizontally until the line meets the curved 8 bar upstream line. At this point read vertically downwards where it will be seen that either a ½" BRV2S5 or BRV2B5 will be required.
TI-P045-09 CTLS Issue 8
Page 4 of 6
BRV2S5 and BRV2B5 Gunmetal Pressure Reducing Valves
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