Categories of exhibits
Diffusion Pump AX-65
Exhibit no. 336
The pump known as a diffusion pump is a vapor jet pump, which transports gas by momentum transfer on collision with the vapor stream. Pump fluid is heated in a boiler (located on the bottom of the pump) until it vaporizes. The vapors flow up the chimney and out through a series of nozzles at supersonic speed. The nozzles direct the vapor stream downward and toward the cooled outer wall where the vapors condense and return to the boiler. The gas that diffuses into the supersonic vapor stream is given a downward momentum and is ejected into a region of higher pressure. Diffusion pumps usually have several stages. Each stage compresses the gas to a successively higher pressure than the preceding stage as it transports it toward the outlet. The pump was invented in 1915 by a German physicist and pioneer of vacuum engineering Wolfgang Gaede.
The exhibit is the AX-65 air-cooled diffusion pump from Saturn 2000R, an ion-trap MS detector for GC/MS manufactured by Varian Inc. in 2000. The pump has aluminum three-stage jet assembly and it was filled with 30 ml of polyphenyl ether fluid Santovac 5. A fan blowing across the pump ensured the efficient cooling of the pump body.
