It depends on the condition of the stator. If there is heavy scoring in 
the stator it would probably not be economical to have them rebuilt. These 
belt-driven pumps were built more rugged than some of the direct-drive 
pumps which replaced them. They also ran slower and hence cooler than 
their direct-drive replacements. Their disadvantage was size/weight.

Richard A. Berger
Mass Spectrometry Resource
Department of Medicine
Washington University Medical School
660 S. Euclid Avenue
St. Louis, MO 63110
314-362-2602

On Wed, 14 Dec 2005 11:55:08 -0600, Dr. Huiming Bao <[log in to unmask]> wrote:

>Dear Colleagues:
>I have five or six Welch Duo-Seal (Model 1400) mechanical (belt driven)
>pumps that are all have some sorts of problems, either electrical or
>unable to pump down to milli-torr level. These pumps are ~ 10 to 15
>years old. I liked them because they were very quiet during operation.
>My studnets and I tried to repair them, but they didn't improve much.
>Now, before I toss them out, should I give them a try at a professional
>mechanical or repair shop?  (I guess I know Marilyn's view).
>
>Have a nice one.
>
>Huiming
>
>--
>Huiming Bao, Assistant Professor
>Department of Geology & Geophysics,
>E235 Howe-Russell Geoscience Complex
>Louisiana State University
>Baton Rouge, LA 70803, USA
>Tel: 225-578-3419 (office), -3413 (lab)
>Fax: 225-578-2302
>http://www.geol.lsu.edu/Faculty/Bao