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Control systems Pressure reducing/surplussing valves
Dimensions/weights (approximate) in mm and kg
B
Size
A
B
C
Weight
Leakage line, " BSP
DN25
100
138
305
2.5
DN40 DN50 DN65 DN80 DN100
115
200
345
6.5
125
200
355
6.5
175
240
690
26.0
175
240
690
26.0
175
240
690
26.0
C
Sizing The required Kv can be calculated from the following formulae, Where:
s = Steam mass flow (kg/h) = Liquid volume flow (m 3 /h)
A
g = Gas flow at standard conditions: 0 °C @ 1.013 bar a (m³/h)
4.6 150
P 1 = Upstream pressure (bar absolute) P 2 = Downstream pressure (bar absolute)
A
P 1 - P 2
c =
(pressure drop factor)
P 1 S = Specific gravity T = Absolute average gas temperature (Kelvin = °C + 273)
Critical pressure drop: P 2
0.58 P 1
Steam
Non-critical pressure drop: P 2
0.58 P 1
Gas
Liquid
Calculating the Kv and selecting a suitable valve Using your maximum flowrate and smallest differential pressure (P 1 – P 2 ), calculate the required Kv from one of the above formulae. Select a valve Kv that is 30% greater than the calculated Kv. The optimum working range of the selected valve should ideally be within the range of 10 to 70% of its Kv.
Saturated
10 to 40 m/s
Steam
Superheated
15 to 60 m/s
Recommended fluid velocities
up to 2 bar g
2 to 10 m/s
Gas
above 2 bar g
5 to 40 m/s
Liquids
1 to 5 m/s
TI-P186-10 CMGT Issue 4
Page 4 of 5
SRV66HC High Capacity Sanitary Pressure Reducing Valve
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