Heavy Duty Balanced Opposed Compressors

FOR MODELS: JG AND JGA SECTION 4 - LUBRICATION AND VENTING
Force Feed Balance Valves
Balance Valves are used in high differential-pressure distribution-block applications to
reduce system problems such as bypassing, no-flow switch errors or blown rupture discs. A
force feed balance valve is shown in Figure 4-10:.
Setting and Maintaining Balance Valves
Valve Cap
Lock Nut
FIGURE 4-10: FORCE FEED BALANCE VALVE
Balance valves cannot be set prior to operating the unit. Ensure that all fittings are tight and
any known leaks have been fixed.
Purge the force feed lube system with a high-pressure hand pump, using the same injection
oil that is used in service, to remove any trapped air or gas in the system. DO NOT USE
ANY OTHER FLUIDS FOR PURGING!
Start up the compressor and bring up to normal operating pressure. After the operating pressures
have stabilized, adjust the cap on the top of the balance valve if necessary. Loosen
the locking nut on the top of the balance valve directly under the cap. Turn the cap clockwise
to increase the pressure and counter clockwise to decrease the pressure. Retighten the
locking nut against the cap.
Set the balance valves and maintain at approximately same pressure on each pressure
gauge in the injection lines of the pump system affected. A system should be set and maintained
within 500 psi (3400 kPa) total or less. The closer the individual line pressures are
maintained, the more reliable the system will become.
Once the balance valves have been set, they should be checked 4 to 6 hours later to ensure
the pressures have not changed and caused another imbalance. If readjustment is necessary
the gauges should be checked again in 4 to 6 hours. If a pressure gauge in a line with a
balance valve is reading more than 500 psi (3400 kPa) higher than the others, try to reduce
the pressure on that particular injection line. If reducing the balancing pressure on the balance
valve does not drop the pressure, then the other balance valves will need to be
adjusted to match the highest pressure.
To set balance valves equipped with a distribution block inlet gauge only:
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