US 3,942,716 AGranted

Flow-thru vacuum bushing for ultracentrifuges

AssigneeBeckman Instruments, Inc.

InventorsKenneth E. Jacobson, Gary C. Thomas

Life of this patent

Estimating the term…

Loading patent…

Abstract

A vacuum bushing for an ultracentrifuge that minimizes excessive oil loss due to the high pressure differential across the bushing and allows automatic reclaiming and reusing of a major portion of the uncontaminated oil flow. The bushing is provided with first and second annular chambers, one chamber being connected to an atmospheric oil reservoir and the other chamber being connected to a vacuum oil reservoir. The major oil flow is from the atmospheric reservoir to the first chamber, along the rotor drive shaft to the second chamber, and then to the vacuum reservoir. The vacuum reservoir is connected to the atmospheric reservoir by a one-way check valve so that the oil is automatically returned to the atmospheric reservoir when the centrifuge is deactivated and the vacuum released.

Claims9

Dependent claims

In a vacuum centrifuge of the type including:

a bushing through which a rotor drive shaft passes from atmospheric conditions into an evacuated rotor chamber, said bushing having a first annular chamber surrounding said drive shaft adjacent the atmospheric side of said bushing;
a first oil reservoir at atmospheric pressure;
and first conduit means for conducting oil from said first atmospheric oil reservoir to said first annular chamber, said first atmospheric oil reservoir being positioned at a greater height than said first annular chamber whereby said oil flows by gravity to said first annular chamber, said oil flowing from said annular chamber along said shaft primarily towards said rotor chamber, the improvement wherein said bushing has a second annular chamber surrounding said drive shaft and positioned between said first annular chamber and said rotor chamber and comprising:
a second oil reservoir adapted to have air pressure evacuated therefrom;
second conduit means for connecting said second annular chamber to said second oil reservoir;
and
said drive shaft and said bushing being so arranged and constructed as to produce a restriction to the flow of oil along said shaft between said second annular chamber and said rotor chamber which is substantially greater than the restriction to flow of oil in said second conduit whereby substantially all of said oil flowing along said shaft is directed from said second annular chamber via said second conduit means to said second oil reservoir when said second oil reservoir has air pressure evacuated therefrom.

4 more elements

A vacuum centrifuge comprising:

a source of vacuum;
a rotor chamber adapted to be connected to said source of vacuum;
a rotor within said chamber;
a rotor drive shaft for driving said rotor;
a bushing positioned within the base of said rotor chamber, said drive shaft passing from said rotor chamber through said bushing to a drive means situated in atmospheric conditions, said bushing having first and second axially spaced annular chambers surrounding said drive shaft, said first annular chamber being positioned adjacent the atmospheric side of said bushing, said second annular chamber being positioned adjacent the vacuum side of said bushing;
a first oil reservoir at atmospheric pressure being positioned at a height above said first annular chamber;
a second oil reservoir adapted to be connected to said source of vacuum and being positioned at a height above said first oil reservoir;
first conduit means for conducting oil from said first reservoir to said first annular chamber, said oil flowing from said first annular chamber along said shaft primarily towards said rotor chamber;
second conduit means for conducting oil from said second annular chamber to said second reservoir;
said rotor drive shaft and said bushing being so constructed and arranged as to produce a restriction to the flow of oil along said shaft from said second annular chamber to said rotor chamber that is substantially greater than the restriction of oil in said second conduit to said second oil reservoir when said second oil reservoir has air pressure evacuated therefrom whereby substantially all of said oil flowing along said shaft is directed from said second annular chamber via said second conduit means to said second oil reservoir when said second oil reservoir has air pressure evacuated therefrom;
and
third conduit means for conducting oil from said second oil reservoir to said first oil reservoir when said second oil reservoir is at atmospheric pressure.

9 more elements

Dependencies are inferred from the claim text.