Product Overview | Gas Regulator
7337-4 Regulators reduce high gas supply pressures to practical use levels. Since capacities will vary with the pressure drop across the regulator, due care must be exercised in properly sizing both the regulator and downstream piping. SPECIFICATIONS
INSTALLATION
The North American 7337-4 Regulator may be installed in any orientation as long as flow through it matches the direction arrow cast on the body. Normal installation is with the spring case vertical above the body. OVERPRESSURE PROTECTION Like most pressure-reducing regulators, the 7337-4 Regulators have outlet pressure ratings that are lower than the inlet pressure ratings. Therefore, a pressure relieving or pressure limiting device is needed if the inlet pressure can exceed the outlet pressure rating, see "Specifications". This regulator does not have an internal relief feature. CAPACITY INFORMATION Table C provides the natural gas regulating capacities of the 7337-4 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.
Body Sizes and End Connections: 2" NPT Maximum Operating Inlet Pressure: See Table B Capacities: See Table C
SELECTION When selecting a regulator, specify its complete designation in- cluding pipe size code and spring designation or outlet pressure range. Example: Select a regulator for 50,000 scfh of 0.6 specific gravity natural gas from 20 psig supply pressure to 16"w.c. outlet pressure. Maximum Emergency Inlet Pressure: 125 psig (8.6 bar) Maximum Outlet (Casing) Pressure: 15 psig (1.0 bar) Maximum Operating Outlet Pressure to Avoid Internal Parts Damage - The Outlet Pressure Rating: 3 psig (0.21 bar) above outlet pressure setting Temperature Capabilities: -20° to 150°F (-29° to 66°C) Pressure Registration: An external downstream control line is required
To determine the wide-open flow capacity of a regulator for relief sizing, use the following formulas.
For critical flow (P outlet absolute ≤ ½ P inlet absolute):
Q = 2322 * P
Solution: Entering Table C at the smallest regulator with this capacity and correct spring range yields a 7337-4-G16.
For non-critical flow (P outlet absolute > ½ P inlet absolute):
97.63 (
)
√
P P
1800 P sin √ 520 GT
[ as degrees]
Table A. Specific Gravity Correction Sp Gr Factor 0.4 1.22 0.6 1.00 1.0 0.774 1.5 0.632 2.0 0.547
Q =
G P Q
= gas specific gravity (air = 1.0)
= inlet pressure, psia = flow rate, SCFH
T
= absolute temperature of gas at inlet in ºRankine = differential pressure, psi (The difference between the regula- tor inlet pressure and the maximum outlet pressure that can be tolerated by downstream components)
DP
If the specific gravity of the gas is other than 0.6, divide desired flow by gravity factor to get equivalent flow of natural gas; then select regulator from Table C.
Multiply a given size regulator's natural gas capacity by gravity factor to get regulator capacity with different gas.
Bulletin 7337-4 Page 2
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