Control systems Self-acting controls
4
Table 3 Valve sizing for cooling applications using water
A
Kvs value
Size DN
Type
B
A
94
80
NSRA
C
NSRA
B
65
65
D
KX/KY
C
34
50
E E F G H I J K
KX/KY
D
23.7
40
KX/KY
E
16.48
32
F
9.8
25
KX
G
6.8
25
SBRA
H
4.64
20
KX
I
3.86
20
SBRA
4.5 5
J
2.9
15
KX
K
2.58
15
SBRA
L
BXRA/ BMFRA/ BMRA
L
0.59
15
Differential pressure bar (x 10 = m wg, x 100 = kPa)
Sizing example Given: - Pressure at valve inlet - Pressure at valve outlet - The required steam flowrate
Differential pressure
P 1 = 14 bar g P 2 = 13 bar g
Flow
= 3 litres/second
P
P
To size the valve: 1. Determine the differential pressure across the valve P 1 - P 2 = 14 - 13 = 1 bar 2. Enter the chart with a flowrate of 3 litres/second and draw a horizontal line to intersect the differential pressure line at 1 bar. From this intersection draw a line parallel to the diagonal lines in the direction of the valve selection boxes. 3. From the valve selection boxes choose the valve with the higher Kvs value i.e. size DN32 'KX' or 'KY' type valve with a Kvs of 16.48
TI-S21-07 CTLS Issue 6
Page 5 of 13
2-Port Self-acting Temperature Control Valve Selection for Heating and Cooling Applications
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