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Vacuum Atmospheres Company
- General Description
- The VAC Glovebox is a controlled atmosphere apparatus. It provides an inert environment for handling highly reactive materials.
- The Glovebox has four accessories used to create and monitor its atmosphere:
- - Pedatrol (PC-1): Provides manual and automatic control of the pressure in the glovebox.
- - Dri-Train (HE-493): Removes excess oxygen and moisture from the atmosphere in the glovebox.
- - Oxygen Analyzer (AO-316-C): Monitors trace oxygen in the inert atmosphere in the glovebox.
- - Moisture Analyzer (AM-2): Monitors moisture content in the inert atmosphere in the glovebox.
- Operating Instructions
- Creating an Inert Atmosphere
- Set the left red pointer of the photohelic to 5-inch positive, and the right red pointer to 4-inch positive.
- Turn the photohelic on.
- Open the refill valve to the loading chamber half way. Also open the loading chamber hatch.
- This causes the pedatrol to continually push the inert gas in and push out the existing gas.
- The pressure on the inert gas can be raised from 20 psi to 40-50 psi to speed the process.
- Never let the pressure in the glovebox drop below 2-inches positive
- Approximately 8 glove box volumes of gas should be used for a good purge.
- Close the loading chamber hatch and the loading chamber refill valve.
- Set pedatrol to normal operation pressure and return inert gas regulator to 20 psi.
- After purging Oxygen content should be ~200 ppm.
- Sample Handling
- Passing specimens and instruments into the glovebox.
- Make sure that the refill valve and the chamber hatch on the inside of the glovebox are closed.
- Open the chamber hatch on the outside of the glovebox.
- Load specimens and instruments.
- Make sure that all bottles are open and any part of anything going in is not capable of holding air. If not the glovebox could be contaminated.
- Close outer hatch.
- Open evacuate valve and wait for it to vacuum to as far as it can (usually takes a few minutes).
- Open refill valve partially- watch the pressure on the pedatrol and make sure the pressure doesn't drop too low- and refill chamber until pressure in chamber is 10 in Hg.
- Open evacuate valve again and repeat previous steps 2 or 3 times to ensure that there is no residual air.
- After repeating open refill valve slowly until chamber is same pressure as glovebox.
- Open chamber from glovebox end.
- Pedatrol Operation
- Manual Operation
- Turn the Photohelic 'off.'
- Using the foot pedal:
- - Raise pressure by pressing on right side of pedal.
- - Lower pressure by pressing on left side of pedal.
- Pressure is still shown on the Photohelic even though it is off.
- Automatic Operation
- Turn the Photohelic 'on.'
- Set the desired pressure of the glovebox using the Photohelic:
- - Set the maximum high pressure with the left red pointer.
- - Set the minimum low pressure with the right red pointer.
- The pressure will remain as desired as long as the Photohelic is on and there is enough inert gas pressure.
- Dri-Train Operation
- Follow the instructions on the side of the regeneration controller:
- Close A & B valves (Dri-Train inlet and outlet valves), turn timer to start.
- Turn switch to regenerate.
- Make sure the the forming gas is turned on.
- After the heat cycle ends(3 hours) be there when the regeneration cycle switches to purge. The alarm for the gas will most likely go off a few times. Reset it and set the flow to 5 psi.
- After 5 hours, minimum, turn switch off, open valve B (the Dri-Train Outlet Valve).
- After 10 hours, minimum, open valve A (the Dri-Train Inlet Valve).
- Change the oil in the vacuum pump.
- Make sure the dri-train and blower are plugged in.
- Open the valves.
- Regenerate once a month if used often.
- Oxygen Analyzer Operation
- Note: perform this operation quickly, the longer the fuel cell is exposed to 209,000 ppm Oxygen, the longer it takes to recover.
- Place range switch on CAL.
- Hold CALIBRATE/NORMAL switch to CALIBRATE. The analyzer is now taking a sample of air from the fish pump on top of the analyzer.
- Adjust the flow meter so that the flow rate is 1 scfh.
- Unlock the "span" control knob.
- Adjust until the meter pointer is over the "CAL" mark on the scale. This is the air calibration.
- Relock the "span" knob.
- Release the CALIBRATE/NORMAL switch.
- <1 ppm Reference Mode
- This mode gives a reference to a known substance with <1 ppm Oxygen content.
- Switching to this should yield <1 ppm, although I've never seen it below 3 ppm.
- Turn the forming gas on.
- Set flow to 1 scfh.
- Make sure that the forming gas is on.
- Sampling Mode
- Switching to this takes a sample of atmosphere from the glovebox.
- If the glovebox is calibrated correctly an accurate reading of Oxygen content will be displayed.
- Replace the fuel cell once a year.
- Last replaced: July 2005
- Moisture Analyzer Operation
- Turn knob from 'off' position to the calibrate 'cal' position.
- After 15 minutes the meter should read 1327 +/- 3
- If not refer to manual, if so continue using
- Turn knob to the 'read' position
- The value on the display is not the moisture content in ppm, but is a reference.
- Use this chart to decipher the amount of moisture in the glovebox.