Capacity | High Pressure Gas Regulator
CAPACITY INFORMATION
For critical flow: (P outlet absolute ≤ ½ P inlet absolute)
Q = P C g * 1.29
Table D provides the natural gas regulating capacities of the 7339 regulators at specific inlet pressures and outlet pressure settings. Flows are in SCFH (60°F and 14.7 psia) of 0.6 specific gravity gas. For specific gravity conversion factors to other gases, refer to the “Selection Section”.
For subcritical flow: (P outlet absolute > ½ P inlet absolute)
) P P
(
√
√
3417 C 1
520 GT
Q =
C g P sin
C g C 1 G
= See Table C = See Table C
To determine wide-open flow capacity of regulator for relief sizing, use the following formula.
= gas specific gravity (air = 1.0)
P
= inlet pressure, psia = flow rate, SCFH
Q
T
= absolute temperature of gas at inlet in ºRankine = differential pressure, psi (The difference between the regulator inlet pressure and the maximum outlet pressure that can be tolerated by downstream com- ponents)
P++
Table B. 7339 Regulator Control and Slam-Shut Spring Ranges
Slam Shut Spring (optional)
Pressure Range Control (Outlet) Spring Color
Approx. point at which internal relief starts to discharge
Trip Range
7 to 20"w.c. 16 - 40"w.c. 1-3.5 psig
Unpainted
24"w.c. - 2.8 psig 24"w.c. - 2.8 psig
10"w.c. above setpoint 20"w.c. above setpoint
Purple
Lt. Blue
2.0-7.3 psig 2.0-7.3 psig 3.2-11 psig 3.2-11 psig 5.8-21 psig
2.75 psig above setpoint
2.75-6 psig
Orange
3.5 psig above setpoint
5-16 psig
Red
6 psig above setpoint
14-35 psig*
Zinc
—
—
* This spring is not available in the "slam-shut" versions. — Not available
Table C. 7339 Regulator Inlet Pressure Ratings and Flow Coefficients
Regulator Designation
Max. Inlet Pressure psig
C1 (when ∆ P>10 psi)
Orifi ce Size
C1 (when ∆ P<10 psi)
C g
C v
7339-_-0
53 53 117 117
2.0 2.0 4.2 4.1
26 26 30 30 30 38 32 36 36 37
26 26 28 28 28 36 30 35 34 35
1/4" X 3/8"
7339 w/slam-shut
7339-_-0
3/8"
7339 w/slam-shut
175
7339-_-0
203 184 437 421 725 910
7 5
1/2"
7339 w/slam-shut
7339-_-0
14.1 11.9
3/4"
150
7339 w/slam-shut
7339-_-0 7339-_-0
1"
100
20.7 25.3
1-3/16"
80
Bulletin 7339 Page 3
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