Control systems Self-acting controls
4
Table 1 Valve sizing for heating applications using steam
Kvs value
Size DN
Type
BX2/ BMF2/ BM2 BX3/ BMF3/ BM3 BX4/ BMF4/ BM4 BX6/ BMF6/ BM6
0.38
15
A
0.64
15
B
1.03
15
C
1.65
15
D
2.58
15
SB
E
2.9
15
KA
F
4.5 3
3.86
20
SB
G
4.64
20
KA
H
6.8
25
SB
I
A
9.8
25
KA/KB
J
B
KA/ KB/KC
16.48
32
K
C D E F H G
16.48
40
KC
L
23.7
40
KA/KB
M
KA/ KB/KC
34
50
N
I
P O N
L, M
K J
65
65
NS
O
Sizing example Given: - Pressure at valve inlet - Pressure at valve outlet - The required steam flowrate
94
80
NS
P
Differential pressure
P 1 = 6 bar g P 2 = 4 bar g
= 280 kg / h
Flow
To size the valve: 1. Determine the differential pressure across the valve P 1 - P 2 = 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 (P 1 - P 2 ) 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 P P
TI-S21-07 CTLS Issue 6
Page 3 of 13
2-Port Self-acting Temperature Control Valve Selection for Heating and Cooling Applications
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