All of the glove boxes should be regenerated once a month for optimal performance. Should there be a large chemical spill or a chemical release that would compromise the integrity of the dry box catalyst, then the box should be regenerated ASAP!
It takes about 16 hours for complete regeneration of the catalyst in the dry box. The most convenient time to start a regeneration cycle is in the late afternoon, so that it can run over the course of the evening.
- Unplug the fan (located in upper left corner).
- Close off the catalyst so that air does not circulate through it. The catalyst is located on the left side of the box and is vertically oriented; the circulation.valves are above and below the catalyst. To close the valves, pull them until they are perpendicular to the pipes.
- Purge the box atmosphere for 10 minutes by opening the large antechamber to full N2 flow and very SLIGHT vacuum simultaneously.
- Cycle the large antechamber N2/vac at least 3 times.
- Place both antechambers under static vacuum (evacuate the chamber, then close the vacuum valve so that it is no longer connected to the vacuum).
- Turn off the pump (pull out the large white plug from the wall socket to the right of the box).
- Disconnect the rubber tubing between the large chamber and the vacuum pump at the point where the tubing connects to the top of the pump.
- Reconnect the rubber tubing so that the large bulb vacuum flask is located between the chamber and the pump. The L-joint tubing of the bulb vacuum flask should connect to the vacuum pump; the other end should connect to the chamber tubing.
- Turn pump back on. Place vacuum flask under N2. Adjust height of dewar with black metal pedestal and jack.
- Regenerating gas (95%N2/ 5%H2) is usually kept in the easternmost gas closet with other cylinders of H2. The appropriate regulator is stored under the hood 5/6 sink (outside of the regulator box, so that it doesn't get dinger), and the blue regulator hose is kept under the hood 3/4 sink.
Connect the regulator and hose to the regenerating gas cylinder. Connect the other end of the hose to the valve located near the outside bottom right corner of the box. The hose has a ball joint; pull the outside sheath back, place the hose over the valve, and release the sheath.
Start the H2 flow. The pressure should be around 40 psi. Mark the metal part of the regulator with a pen so you can remember how much gas was in the cylinder.
- Turn the regeneration crank (left side of the box) a little past start. (This will heat the catalyst.) Flip the switch to regen. Top off N2 before going home, and leave overnight.
- Flip the switch off.
- Check the H2/N2 gas regulator and make sure that gas was actually used. Turn off the regulator.
**If no gas was used, there may be a problem with the regulator or the catalyst valves. Check with senior lab members.
- Disconnect the regeneration gas tubes.
- Turn off the pump. Take N2 off the vacuum flask.
- Open the vacuum seal. Quickly disconnect and take the bottom half of the flask to the aqueous waste (you can leave it inverted over the waste bottle until it melts).
- Reconnect the original rubber tubing between the large chamber and the vacuum pump.
- To change pump oil: You may want to wait until the oil has cooled down. Unscrew the grey plastic cap from the top of the pump.
- Have a metal pan ready to catch the old oil. Use a slot screwdriver to open the plastic drainage stopcock on the front face of the pump. Oil should flow into the pan.
- Replace the drainage stopcock. Discard the old oil. Add 1.5~2 L of fresh oil through the top of the pump. Replace the cap.
- Turn on the pump and make sure there are no terrible noises. If there are, turn off and add more oil and/or ask senior lab members.
- Re-open the catalyst valves.
- Replug the internal blower fan.