On Sun, 09 Mar 2008 11:46:35 GMT, Steve R. wrote:

"DoN. Nichols" wrote in message
...

Based on the intended use, it may not *have* any oil. It may be
a diaphragm type pump, or a rotary vane pump. The intended use does
*not* need the high vacuum which an oil filled pump can produce.

It may be a few days before I can photograph it. Rain is pending, and I do
not want to bring it into the house until it's sterile.

There is a third type of suction pump used in biomedical applications,
uses a heating element inside an air canister, with check valves on the
input and output. Heating element cycles on, air expands & gets pushed
out one side. Heater turns off, it sucks air in through the other
checkvalve. If nurses hook it up wrong or if the jar to catch the blech
gets full, all that crud gets sucked into the canister & cooks on the
heating element. Probably the worst job I ever had to do as a biomed
tech was to fix that.