Control valves
Self-acting controls
Page 4 of 12
Kvs
value
Size
DN
94
80
65
65
34
50
23.7
40
16.48
32
9.8
25
6.8
25
4.5.5
Type
NSRA
NSRA
KX / KY
KX / KY
KX / KY
KX
SBRA
KX
SBRA
KX
SBRA
4.64
20
3.86
20
2.9
15
2.58
15
0.59
15
BXRA / BMFRA
/ BMRA
Table 3 Valve sizing for cooling applications using water
��
��
Differential pressure bar (x 10 = m wg, x 100 = kPa)
Sizing example
Flow
Differential
pressure
P1
P2
Given:
- Pressure at valve inlet P
1
= 14 bar g
- Pressure at valve outlet P
2
= 13 bar g
- The required water flowrate = 3 litres/second
To size the valve:
1. Determine the differential pressure across the valve P
1
- P2 = 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
2-Port Self-acting Temperature Control Valve Selection
for Heating and Cooling Applications
TI-S21-07 CH Issue 1
Page 4 of 12
F
l
o
w
m
3
/
h
F
l
o
w
l
/
s
