diffusion vacuum pumps

Date1930-1950

Inventory Number1996-1-0312

ClassificationVacuum Pump

Maker Distillation Products Industries ? founded 1930

Cultural Region

Dimensions24 × 20.5 × 13.3 cm (9 7/16 × 8 1/16 × 5 1/4 in.)

Material

DescriptionA stout metal cylinder, one end of which is flat and rimmed, and the other end of which is rounded, serves as the base. Two additional thinner cylinders, one taller and wider than the other, emerge from the rounded end of the base. The protruding ends of the two cylinders are capped, with a narrower hollow cylinder emerging from the center of the two caps. Near the top of the two main cylinders is a hardened black liquid, perhaps tar or a lubricant. Wrapped around the cylinders (four times around the small cylinder and five times around the large one) and fixed in place, is a tube that extends past the object; it extends horizontally from the small cylinder and horizontally and then vertically from the large cylinder. The tube has at or near both ends a fitted nut. The gray paint that covers the entire object is stained and scuffed; one may also see red speckles along the middle portion.

Signedunsigned

Curatorial RemarksSimilar to 1996-1-0281a,b,c.

FunctionUsed to force gas molecules out of a chamber. Instead of a piston creating the vacuum, it is done by a stream of molecules (generally oil) flowing in the direction away from the system to be evacuated. These oil molecules carry the air molecules away with them.

Diffusion pumps are used as an additional stage between the system to be evacuated and a mechanical pump.

Since this pump is made of metal, it is not possible to see its interior. However, there are two diffusion pumps in the collection that illustrate how this one may work: one is a similar version to this one that has been sliced open (1996-1-0281b), and another which is made entirely of glass (1998-1-0034).