It is straight forward to change the vacuum pump on one of the Edwards pumping assemblies that Oxford supplies.
1. Isolate the magnet by turning off the valve at the base of the magnet to prevent any thing from happening if there should be a temporary loss of vacuum in the line. (Experience at Minnesota was that the magnet could be isolated for several hours and only show a temperature increase of about 0.01 deg. K.)
2. With the good pump running as it normally would, switch the pump control for the bad pump off. This should shut off the pump and close the vacuum solenoid valve above it. This effectively isolates the pump.
3. Unplug the power cord from the pump, and take off the clamp at the vacuum port. Take out the bolts securing the pump to the pumping platform.
4. Remove the pump, making sure that the manifold between the pumps is supported somehow. The solenoid for the bad pump will not be supported when the pump is out. It is heavy and without support will weigh down the line.
5. Put the new pump in, connect the power and vacuum, put the bolts back in and turn it on. If everything seems normal open up the vacuum valve at the base of the magnet.
I have done this procedure several times myself. The whole process shouldn't take more than 15 minutes.
David Live
Complex Carbohydrate Research Center
University of Georgia
315 Riverbend Rd.
Athens, GA 30602
Phone: 706-542-6262
Received on Tue Mar 20 2007 - 07:53:41 MST