Replace a Gas Cylinder
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These instructions apply to working with inert gases only. When working with hazardous gases, follow the safety procedures established by your lab.
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A power failure or loss of cryogen can result in dangerous pressures in the sample chamber. When using toxic or flammable gases, additional venting of the cabinet may be required.
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- Gas tubing to instrument
- Gas regulator shut-off valve
- Low pressure gauge
- High pressure gauge
- Gas cylinder shut-off valve
- Regulator connecter nut
- Regulator control knob
- Brass reducer fitting
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Disconnect a Depleted Gas Cylinder
- Close the regulator shut-off valve and gas cylinder shut-off valve by turning the knobs clockwise.
- Disconnect the gas line from the regulator. Gas will be vented from the line. It is not necessary to disconnect the gas line from the analyzer inlet if the cylinder will be replaced immediately with one of the same type.
- Open the gas regulator shut-off valve by turning the knob counter-clockwise. Gas will be vented from the regulator.
- Turn the regulator control knob clockwise to open and vent any remaining gas. Both gauges should read at or near zero. If not, make sure the gas regulator shut-off valve is open.
- Close the regulator by turning the control knob counter-clockwise.
- Use an appropriate wrench to loosen the nut at the regulator connector nut then remove the regulator from the cylinder.
- Replace the protective cap on the depleted cylinder. Disconnect the retaining strap and move the cylinder to an appropriate location.
Connect a Gas Cylinder
Regulator Pressure Settings
Analyzer |
Gauge should indicate |
Gemini |
15-18 psig (103 - 124 kPag) |
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Exceeding the maximum recommended air pressure could cause personal injury or damage the instrument. |
Move the replacement cylinder close to the analyzer and tether it into place.
- Use an appropriate cylinder wrench to remove the protective cap from the replacement gas cylinder.
- Place the protective cap in a secure location. It will be needed to recap the gas cylinder when it is depleted and replaced.
- Attach the gas regulator to the gas cylinder connector. Hand tighten the nut, then use an appropriate wrench to tighten an additional 3/4 turn.
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Over-tightening the fitting may cause a leak. |
- Check for leaks at the high pressure side of the regulator and in the connector.
- Turn the regulator control knob fully counter-clockwise.
- Slowly open the gas cylinder shut-off valve, then quickly close it.
- Observe the pressure on the high pressure gauge for approximately one minute.
- If the pressure is stable, proceed with the next step.
- If the pressure decreases, tighten the regulator connector nut until it becomes stable. If the pressure does not remain stable, remove the regulator and clean all contacts at the regulator connection, then reinstall the regulator.
- Purge the air from the lines by doing the following:
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Purge the regulator before proceeding to prevent contamination of the analysis gas supply. |
- Open the gas cylinder valve to pressurize the regulator, then close the valve.
- Adjust the Pressure Control knob to approximately 5 psi.
- Turn the regulator Shut-off valve counter-clockwise to open. Allow gas to flow until both gauges read approximately zero.
- Close the regulator Shut-off valve to stop gas flow.
- Reconnect the gas line to the regulator.
- Use two 7/16 in. (11 mm) wrenches to tighten the gas line connection. Hold one wrench fitting steady and the other to tighten the connector nut.
- Set the analyzer pressure by doing the following:
- Turn the Regulator Control knob clockwise until the low pressure gauge indicates the appropriate pressure. See the Regulator Pressure Settings table in Connect a Gas Cylinder.
- Open the regulator Shut-off valve.
- Open the gas cylinder Shut-off valve and flow gas for 10 to 30 seconds.
- Close the gas cylinder Shut-off valve.
- Close the gas cylinder valve.
- If the gas line to the instrument inlet was previously disconnected, reconnect it now.