Hickman's three-stage self-fractionating diffusion pump
Datecirca 1940
Inventory Number1998-1-0034
ClassificationVacuum Pump
Subject
Maker
Distillation Products Industries
founded 1930
Cultural Region
Place of Origin
Dimensions33 x 53 x 11.8 cm (13 x 20 7/8 x 4 5/8 in.)
Material
DescriptionA complex glass tube. It consists of a horizontal section tilting slightly downwards to one side, curving upwards at both ends into vertical sections. Both vertical sections are closed at their ends but they each have a narrower side tube that extends horizontally from them and which is open at the end (now they are both stoppered by a cork). This specific design is described in the field as a 4 compartment-, 3 jet- fractionating diffusion pump.
The vertical section on one side (inlet) is simple, leading straight to the horizontal section. The horizontal section has three boilers (four including the smaller one, see below) attached below it. These are glass bulbs with heating coils inside. The electrodes of the heating coils of the different boilers are all connected together in series. The bulbs of the boilers are covered in pouches insulated with what looks like fiberglass, but could be felt or asbestos wool. All of the boilers lead into the horizontal section by tubes of different shapes: The first one is a tube that goes straight up, makes a right turn in the direction sloping downwards, and ends as a straight tube with an open mouth; the second one is a narrower tube that hoes straight up and is connected on the side sloping downwards to a trumpet-shaped tube with an open end; the third tube, which is at the end of the horizontal section, simply leads straight upwards, pointing into the vertical section above.
There is an additional, smaller boiler underneath the inlet tube, which connects to the horizontal section through a narrow tube entering perpendicularly from one side between the first and second boilers. Another narrow tube leads down from the bottom of the horizontal section near the first boiler, to a tube below that connects the bottoms of the first and second boiler. At this point between the two boilers, another tube curves around the first boiler to connect at the top of the smaller boiler. The bottoms of the second and third boilers also connect by a straight tube, as do the bottoms of the first boiler and the smaller one next to it. Finally, a tube leads from the lower end of the horizontal section next to the third boiler, down to the base of the third boiler.
All of the boilers and the tubes that connect them at their bottom are currently filled with a dark yellow liquid.
The second vertical section (outlet side) is a long straight cylinder with a middle section that has five consecutive mushroom-shaped bulbs, the fractionating column, which is currently filled partially with a clear yellowish liquid. After the bulbs, the tube narrows down before ending in a narrow tip.
The vertical section on one side (inlet) is simple, leading straight to the horizontal section. The horizontal section has three boilers (four including the smaller one, see below) attached below it. These are glass bulbs with heating coils inside. The electrodes of the heating coils of the different boilers are all connected together in series. The bulbs of the boilers are covered in pouches insulated with what looks like fiberglass, but could be felt or asbestos wool. All of the boilers lead into the horizontal section by tubes of different shapes: The first one is a tube that goes straight up, makes a right turn in the direction sloping downwards, and ends as a straight tube with an open mouth; the second one is a narrower tube that hoes straight up and is connected on the side sloping downwards to a trumpet-shaped tube with an open end; the third tube, which is at the end of the horizontal section, simply leads straight upwards, pointing into the vertical section above.
There is an additional, smaller boiler underneath the inlet tube, which connects to the horizontal section through a narrow tube entering perpendicularly from one side between the first and second boilers. Another narrow tube leads down from the bottom of the horizontal section near the first boiler, to a tube below that connects the bottoms of the first and second boiler. At this point between the two boilers, another tube curves around the first boiler to connect at the top of the smaller boiler. The bottoms of the second and third boilers also connect by a straight tube, as do the bottoms of the first boiler and the smaller one next to it. Finally, a tube leads from the lower end of the horizontal section next to the third boiler, down to the base of the third boiler.
All of the boilers and the tubes that connect them at their bottom are currently filled with a dark yellow liquid.
The second vertical section (outlet side) is a long straight cylinder with a middle section that has five consecutive mushroom-shaped bulbs, the fractionating column, which is currently filled partially with a clear yellowish liquid. After the bulbs, the tube narrows down before ending in a narrow tip.
Signedunsigned
Curatorial RemarksThe maker was ascertained using the Overbeck article (see related works).
FunctionThis is an oil diffusion pump, a type of vacuum pump that is able to attain a much higher vacuum than traditional mechanical pumps. They function as an additional stage between the system to be evacuated at one end, and a mechanical vacuum pump at the other end.
Diffusion pumps are a critical technology for attaining the high vacuums required for many important 20th-century technologies such as vacuum tubes, cyclotrons and electronics. The diffusion pump has no moving parts (one of its advantages) and as in this case, can be even made of glass, although larger versions tend to be in metal.
In diffusion pumps, a stream of molecules of a material (in this case oil) is forced in one direction inside a tube. This stream forces the air molecules away from one of the ends of the tube (the inlet) towards the other end (the outlet).
In order to function properly, the diffusion pump's walls must be cooled, usually by being surrounded by water. This condenses the oil molecules back into liquid when they touch the wall, keeping a continuous flow that returns oil to the boilers and keeps it from saturating the atmosphere inside the tube.
This particular model is called a three-stage pump because each consecutive boiler exerts the effect explained above.
The column on the outlet side with the mushroom-shaped bulbs is called a fractioning column, and is another specific feature of this pump: In this pump the molecules are simply oil vapor produced at the boilers from inexpensive oil. the boiler and cooler system functions as a purification mechanism (oil fractioning) in that as the pump operates, the more volatile, less useful components of the oil will migrate away from the boilers to rest on the fractionating column. The less volatile oils, which are more useful, tend to remain on the lower sections of the pump.
In this pump, even the useful fractions of the oil are separated during its operation, with the more volatile parts migrating to the boilers further from the system to be evacuated, as a better vacuum is created by the stream of oil that is least volatile.
Diffusion pumps are a critical technology for attaining the high vacuums required for many important 20th-century technologies such as vacuum tubes, cyclotrons and electronics. The diffusion pump has no moving parts (one of its advantages) and as in this case, can be even made of glass, although larger versions tend to be in metal.
In diffusion pumps, a stream of molecules of a material (in this case oil) is forced in one direction inside a tube. This stream forces the air molecules away from one of the ends of the tube (the inlet) towards the other end (the outlet).
In order to function properly, the diffusion pump's walls must be cooled, usually by being surrounded by water. This condenses the oil molecules back into liquid when they touch the wall, keeping a continuous flow that returns oil to the boilers and keeps it from saturating the atmosphere inside the tube.
This particular model is called a three-stage pump because each consecutive boiler exerts the effect explained above.
The column on the outlet side with the mushroom-shaped bulbs is called a fractioning column, and is another specific feature of this pump: In this pump the molecules are simply oil vapor produced at the boilers from inexpensive oil. the boiler and cooler system functions as a purification mechanism (oil fractioning) in that as the pump operates, the more volatile, less useful components of the oil will migrate away from the boilers to rest on the fractionating column. The less volatile oils, which are more useful, tend to remain on the lower sections of the pump.
In this pump, even the useful fractions of the oil are separated during its operation, with the more volatile parts migrating to the boilers further from the system to be evacuated, as a better vacuum is created by the stream of oil that is least volatile.
ProvenanceFor information, see Bernie Sousa, Mallinckrodt Chemical Laboratory, Harvard.
P. Grandee
Date: 1720-1750
Object number: 1998-1-1441
Henry Hughes & Son, Ltd.
Date: 1900-1915
Accessories: instruction manual for instrument is in box of disassembled parts.
Object number: DW0141f
William N. Weeden
Date: circa 1885
Object number: 1998-1-0055
W & A. K. Johnston, Ltd.
Date: c. 1872
Accessories: rectangular and round wood stretchers
Object number: 2008-1-0308g
Henry Hughes & Son, Ltd.
Date: 1900-1915
Accessories: instruction manual for instrument is in box of disassembled parts.
Object number: DW0141g
Todd Scientific Company
Date: 1955-1965
Object number: 1996-1-0396
George Washington Pierce
Date: circa 1921
Object number: 1997-1-0376
Sylvania
Date: late 19th-early 20th Century
Object number: RS0368
Crosby Steam Gage & Valve Company
Date: circa 1897
Accessories: small corked glass bottle containing "watch oil"; screwdriver; elbow; mahogany handled stopcock
Object number: 1996-1-0251
See also/See also
