38059-Satchwell Inter. Guide 05

STEAM VALVE SIZING CHART
Example: Required flow: 900 kg/h
Absolute inlet pressure: 2.5 bar
Optimum pressure drop through valve = 40% of 2.5 = 1.0 bar
Ideal Cvs = 27
Nearest available valve has Cvs 25. This is inadequate because the maximum flow = 800 kg/h
∴ Use next larger valve which has Cvs = 40
Pressure drop through valve = 0.45 bar*
Max flow for same inlet pressure & Cvs = 1300 kg/h
6
8
10
0.002
0.003
0.004
20
30
40
50
60
80
100
0.006
0.008
0.01
0.2
0.25
0.02
FLOW COEFFICIENTS: Cvs
0.5
200
300
400
500
600
800
1000
Cvs = Flow in UK gal/min to produce 1lbf/in 2 pressure drop when the valve is
fully open Kvs = Cvs x 1.038.
Kvs = Flow in m 2 /hr to produce 1 bar pressure drop when the valve is fully open.
1.0
0.03
0.04
0.05
0.06
0.08
0.1
CVs Values
2.0
2.5
Steam Flow (kg/h)
0.2
Steam Flow (kg/s)
4.0
SATCHWELL
VALVE SIZING INFORMATION
2000
6.3
10
0.3
0.4
0.5
0.6
0.8
1
16
3000
4000
5000
6000
8000
10,000
2
25
∆p (bar) = flow (m 3 /h) 2
Valve Type 1 /2” 1 /2” 1 /2” 1 /2” 1 /2” 1 /2” 3 /4” 3 /4” 1” 11 /4” 11 /2” 2” 21 /2” 3” 4” 5” 6”
15 15 15 15 15 15 20 20 25 32 40 50 65 80 100 125 150
For full details see Data Sheet
▼
mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm
VEU DS 4.101 – – – 0.63 1.0 1.6 4.0 – – – – – – – – – –
MEU DS 4.101 – – – 0.63 1.0 2.0 4.0 6.0 – – – – – – – – –
FEU DS 4.101 – – – 0.63 1.0 2.0 4.0 5.6 – – – – – – – – –
BFB DS 4.103 0.4 0.6 1.0 1.6 2.0 2.5 – – – – – – – – – – –
VZ, VZX, VZF DS 4.110, 4.101 – – 0.2 0.5 1.0 2.0 4.0 – 8.0 12 20 32 63 80 125 200 315
VSF DS 4.110 – 0.63 1.0 1.6 2.5 4.0 6.3 – 10.0 16 25 40 – – – – –
MB, MBF DS 4.501 – – – – – 1.8 4.0 – 8.0 12 20 32 63 80 120 – –
MZ, MZX, MZF DS 4.610, 4.601 – – – – – 2.5 4.0 – 8.0 12 20 32 63 80 125 200 315
MJF DS 4.610 – – – – 1.0 4.0 6.3 – 10.0 16 25 40 – – – – –
45
40
20,000
3
4
5
30,000
6
8
10
9
8
7
6
5
4
0.3
1
0.9
0.8
0.7
0.6
0.5
0.4
1000
900
800
700
600
500
30
3
100
90
80
70
60
50
40
2
Kvs
* This is only 18% of absolute inlet pressure and the
control quality will not be good until the valve has
partially closed. As with all steam valves this
compromise is necessary since the next smaller valve
would not pass the required flow.
400
2
300
3
200
Pressure Drop (bar)
1.0
0.9
0.8
0.7
0.6
0.5
0.4
Pressure Drop (kPa)
10
9
8
7
6
5
4
200
100
90
80
70
60
50
40
300
0.3
1000
900
800
700
600
500
400
Absolute Inlet Pressure (bar)
Note:
For maximum temperatures, internal
pressures and differential pressures,
refer to Data Sheet DS 4.110.
0.2
30
20
Absolute Inlet Pressure (kPa)
ALTERNATIVE STEAM VALVE SIZING METHOD
0.1
26
20
2000
10
2600
As an alternative to the table the following formulae may be used:-
Q = Required flow in kg/h, P1 = Absolute inlet pressure in Bar.
Required flow less
than 15 kg/h
CVs = Q
8 (P1) 1.56
Pressure Drop (bar)
Absolute Inlet Pressure (bar)
Pressure Drop (kPa)
Absolute Inlet Pressure (kPa)
Required flow greater
than 15 kg/h
CVs = Q
13 (P1) 0.98
Note: The formulae take into account the 40% optimum pressure of drop automatically.