Control valves
Self-acting controls
Page 2 of 12
Kvs
value
Size
DN
Type
0.38
15
BX2 / BMF2 / BM2
0.64
15
BX3 / BMF3 / BM3
4.5.3
1.03
15
BX4 / BMF4 / BM4
1.65
15
BX6 / BMF6 / BM6
2.58
15
SB
2.9
15
KA
3.86
20
SB
4.64
20
KA
6.8
25
SB
9.8
25
KA / KB
16.48
32
KA / KB / KC
16.48
40
KC
23.7
40
KA / KB
34
50
KA / KB / KC
65
65
NS
94
80
NS
Table 1 Valve sizing for heating applications using steam
Sizing example
Flow
Differential
pressure
P1
P2
Given:
- Pressure at valve inlet P
1
- Pressure at valve outlet P
2
- The required steam flowrate
= 6 bar g
= 4 bar g
= 280 kg/h
To size the valve:
1. Determine the differential pressure across the valve P
1
- P2 = 6 - 4 = 2 bar.
2. Enter the upper section of the chart with the inlet pressure (P
1
) at 6 bar g
and draw a horizontal line to intersect the differential pressure (P1 - P2) line at 2 bar. From this intersection draw a vertical line downwards.
3. Enter the lower section of the chart with the steam flowrate at 280 kg/h and draw a horizontal line to intersect the vertical line
produced in step 2. From this intersection draw a line parallel to the diagonal lines in the direction of the valve selection box.
4 From the valve selection boxes choose the valve with the higher Kvs value i.e. size DN20 'KA' type valve with a Kvs of 4.64
2-Port Self-acting Temperature Control Valve Selection
for Heating and Cooling Applications
TI-S21-07 CH Issue 1
Page 2 of 12
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