GE MOA 280i, Operation And Maintenance Manual

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GE Analytical Instruments ©2006 DLM 14291 Rev. A
4-11
Gas for Ozone Generator
The NOA requires oxygen for the ozone generator. The connection to the NOA is
made via a 1/8" Swagelok bulkhead in the back panel, just above the vacuum
pump plug. If oxygen is supplied from a gas cylinder, the cylinder must be
equipped with a two-stage regulator with a shutoff valve on the outlet and an
adapter for connection of 1/8" tubing with Swagelok-brand connections. A 1/4"
female NPT to 1/8" Swagelok union and a 1/4" male NPT to 1/8" Swagelok union
are provided with the analyzer. Wrap Teflon tape on the outlet of the shutoff
valve or the male NPT union to prevent leaks on the NPT connection.
A 6 ft length of 1/8" OD Teflon tubing with brass nuts and ferrules is supplied with
the NOA for connecting the oxygen supply to the bulkhead fitting on the NOA back
panel. Use a 7/16" wrench to remove the protective cap from the bulkhead fitting
“Oxygen Inlet” on the back panel. Connect the Teflon tubing to the bulkhead fitting.
Connect the other end of the tubing to the adapter on the regulator. Use a 7/16"
wrench to tighten the nuts 1/4 turn past finger tight. Turn on the main valve on
the oxygen tank and adjust the outlet pressure on the regulator to 10 psig (~700
mBar, 520 torr or 0.7 kg/cm
2
).
The flow of gas through the ozone generator is ~30 mL/min and is controlled by a
pressure regulator located on the back panel of the NOA. The black knob on the
regulator has two positions; locked and adjust. When pulled out away from the
back panel, the knob can be turned to adjust the ozone gas pressure, when pushed
in toward the back panel, the knob will be locked and the knob will not turn. To
set the pressure, from the NOA Main Menu, press CLEAR to display the Status
Screen. Adjust the regulator until the Supply Pressure is 6.0 ± 0.2 psig (419 mBar,
314 torr or 0.4 kg/cm
2
) .
Oxygen can also be supplied from an E size cylinder or house oxygen. Normally
these are equipped with flow controllers instead of a pressure regulator. Oxygen
tubing with 22 mm connectors, universal oxygen tubing or bubble tubing can be
used to connect the barbed connector of the flow controller to the NOA. In the