MKS Mass-Flo 1179A - Valve Configuration Selection Criteria; Calculating Maximum Flow Coefficient (Cv)

Appendix D: MFC Sizing Guidelines How To Determine the Valve Confi
g
uration
71
How To Determine the Valve Configuration
1. Determine the maximum flow coefficient (C
v
), for the gas of interest, using the equation:
C
V
(max) = Max. Flow Rate, sccm
C
v
Pressure Factor
1.293
Gas Density
( )( )
( )
where:
Gas Density
is listed in
Appendix C: Gas Correction Factors
, page 65.
C
v
Pressure Factor
is listed in Table 12, page 71.
C
v
Pressure Factors (multiplied by 100,000)
P1
(psia)
Differential Pressure (psid)
50 40 30 20 15 10 5 2 1 0.5
165
0.042 0.046 0.052 0.063 0.072 0.087 0.122 0.192 0.272 0.384
150
0.044 0.048 0.055 0.066 0.075 0.092 0.128 0.202 0.285 0.403
125
0.049 0.054 0.061 0.073 0.083 0.101 0.141 0.221 0.312 0.441
100
0.058 0.062 0.069 0.082 0.094 0.113 0.158 0.248 0.349 0.493
75
0.077 0.077 0.082 0.097 0.110 0.132 0.183 0.286 0.404 0.570
50
0.116 0.116 0.116 0.123 0.138 0.164 0.226 0.352 0.495 0.699
30

0.194 0.194 0.194 0.220 0.297 0.458 0.642 0.904
25

0.232 0.232 0.246 0.329 0.503 0.704 0.991
20

0.291 0.291 0.291 0.373 0.565 0.789 1.109
15

0.387 0.387 0.441 0.659 0.915 1.283
10

0.578 0.581 0.821 1.131 1.578
5

1.156 1.232 1.643 2.261
2

2.890 2.905 3.725
1

5.779 5.811
Table 12: C
v
Pressure Factors