Filter
Top Products
262
This larger valve (2 psi drop) has a steeper curve that is fur-
ther away from the desired linear valve characteristic. See
LINEAR VALVE under VALVE SELECTION for more infor-
mation.
Fig. 20. Effect of Pressure Drop in Steam Valve Sizing.
Table 5. Properties of Saturated Steam.
Vacuum,
Inches of
Mercury
Boiling
Point or
Steam
Temp-
erature
(Deg F)
Specific
Volume (V),
cu. ft/lb
(For valve
sizing)
Maximum
Allowable
Pressure
Drop, psi.
29
25
20
15
14
76.6
133.2
161.2
178.9
181.8
706.00
145.00
75.20
51.30
48.30
26.57
12.04
8.672
7.162
6.950
0.23
1.2
2.4
3.7
3.9
12
10
8
6
4
2
187.2
192.2
196.7
201.0
204.8
208.5
43.27
39.16
35.81
32.99
30.62
28.58
6.576
6.257
5.984
5.744
5.533
5.345
4.4
4.9
5.4
5.9
6.4
6.9
Gage
Pressure,
psig
Boiling
Point or
Steam
Temp-
erature
(Deg F)
Specific
Volume (V),
cu. ft/lb
(For valve
sizing)
Maximum
Allowable
Pressure
Drop, psi.
0
1
2
3
4
212.0
215.3
218.5
221.5
224.4
26.79
25.20
23.78
22.57
21.40
5.175
5.020
4.876
4.751
4.626
7.4
7.8
8.4
8.8
9.4
5
6
7
8
9
227.1
229.8
232.3
234.8
237.1
20.41
19.45
18.64
17.85
17.16
4.518
4.410
4.317
4.225
4.142
9.8
10.4
10.8
11.4
11.8
100%
0% 100%
STEM TRAVEL
VALVE OPENING/
STEAM FLOW
C2337
Cv = 41
Cv = 25
LINEAR VALVE
CHARACTERISTIC
V
V
10
11
12
15
20
239.4
241.6
243.7
249.8
258.8
16.49
15.90
15.35
13.87
12.00
4.061
3.987
3.918
3.724
3.464
12.4
12.8
13.4
14.8
17.4
25
30
35
40
45
266.8
274.0
280.6
286.7
292.4
10.57
9.463
8.56
7.826
7.209
3.251
3.076
2.93
2.797
2.685
19.8
22.4
24.8
27.4
29.8
50
55
60
65
70
297.7
302.6
307.3
311.8
316.0
6.682
6.232
5.836
5.491
5.182
2.585
2.496
2.416
2.343
2.276
32.4
34.8
37.4
39.8
42.4
75
80
85
90
95
320.0
323.9
327.6
331.2
334.6
4.912
4.662
4.445
4.239
4.060
2.216
2.159
2.108
2.059
2.015
44.8
47.4
49.8
52.4
54.8
100
110
120
130
140
337.9
344.1
350.0
355.2
360.9
3.888
3.595
3.337
3.12
2.923
1.972
1.896
1.827
1.766
1.710
57.4
62.3
67.4
72.3
77.4
150
160
170
180
190
366.2
370.6
375.5
379.6
383.9
2.746
2.602
2.462
2.345
2.234
1.657
1.613
1.569
1.531
1.495
82.3
87.4
92.3
97.4
102.3
200
225
250
275
300
387.8
397.4
406.0
414.2
421.8
2.134
1.918
1.742
1.595
1.472
1.461
1.385
1.320
1.263
1.213
107.4
119.8
132.4
145.0
157.4
350
400
450
500
550
435.6
448.1
459.5
470.0
479.7
1.272
1.120
0.998
0.900
0.818
1.128
1.058
0.999
0.949
0.904
182.4
207.4
232.4
257.4
282.4
600
650
700
800
900
1000
488.8
497.3
505.4
520.3
533.9
546.3
0.749
0.690
0.639
0.554
0.488
0.435
0.865
0.831
0.799
0.744
0.699
0.659
307.4
332.4
357.4
407.4
457.4
507.4
Gage
Pressure,
psig
Boiling
Point or
Steam
Temp-
erature
(Deg F)
Specific
Volume (V),
cu. ft/lb
(For valve
sizing)
Maximum
Allowable
Pressure
Drop, psi.
V
Appendix A: Valve Selection and Sizing