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US 4,455,026 AGranted
Vee-shaped magnetic/centrifugal seal and method of operation
AssigneeMechanical Technology Incorporated
InventorsOscar Pinkus, Donald F. Wilcock
Life of this patent
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AssigneeMechanical Technology Incorporated
InventorsOscar Pinkus, Donald F. Wilcock
Estimating the term…
A combined magnetic/centrifugal seal for a rotating shaft rotatably journalled within a housing. The rotating shaft has a generally circular cross section and at least one radially extending generally Vee-shaped cross section circumferential portion formed about its periphery. A plurality of radially extending circumferential teeth are concentrically arrayed around the periphery of the rotating shaft in parallel relationship to the Vee-shaped circumferential portion on the rotating shaft on at least one of its sides and spaced closely adjacent thereto. The housing has a complementary generally Vee-shaped cross section within which the Vee-shaped circumferential portion of the rotating shaft rides and in conjunction with the Vee-shaped cross section portion defines a space within which the concentrically arrayed circumferential teeth extend. A magnetically susceptible ferrofluid is disposed within this space for forming a centrifugal seal during high speed rotation of the shaft and the ferrofluid communicates with the gaps formed between the ends of the concentrically arrayed circumferential teeth and the opposite surfaces of the rotating shaft on each side of the Vee-shaped cross section circumferential teeth. A magnetic field is impressed across the gaps thus defined to form a plurality of magnetic seal stages with the shaft at standstill and at low rotating speeds.
A combined magnetic/centrifugal seal for a rotating member rotatably supported within a housing, said rotating member having a generally circular cross section and an enlarged diameter cylindrical drum-like portion with at least one radially extending, generally Vee-shaped in cross section circumferential portion formed about the periphery of the enlarged diameter cylindrical drum-like portion, a plurality of radially extending circumferential teeth concentrically arrayed around the periphery of the enlarged diameter cylindrical drum-like portion in parallel relationship to said Vee-shaped circumferential portion on the rotating member on at least one side thereof and spaced closely adjacent thereto, said housing having a hollow complementary generally Vee-shaped and drum-like cross section portion within which the Vee-shaped and enlarged diameter cylindrical drum-like circumferential portions on the rotating member ride and in conjunction with the Vee-shaped and drum-like cross section portions define a space within which said concentrically arrayed circumferential teeth extend, a magnetically susceptible ferrofluid disposed within the space defined between the complementary Vee-shaped cross section portion of the housing and the Vee-shaped circumferential portion of the rotating member for forming a centrifugal seal during high speed rotation of the rotating member, said ferrofluid also communicating with the gaps formed by the concentrically arrayed circumferential teeth extending within the space defined between said complementary housing portion and the enlarged diameter cylindrical drum-like portion of the rotating member on at least one side of the Vee-shaped circumferential portion, and means for impressing a magnetic field across said last mentioned space to form a plurality of magnetic seal gaps thereacross within which said ferrofluid is trapped with said rotating member at standstill and at low rotating speeds to form a multi-stage seal on at least one side of the Vee-shaped circumferential portion.
The method of operating a magnetic/centrifugal seal of the type comprising a rotor having a generally circular cross section and an enlarged diameter cylindrical drum-like portion with a Vee-shaped cross section peripheral rim portion and rotatably secured within a housing having a complementary hollow drum-like and Vee-shape portion, and a plurality of radially extending circumferential teeth concentrically arrayed around the periphery of the rotor on at least one side of said Vee-shaped rim portion and extending into the space defined between the enlarged diameter drum-like and Vee-shaped cross section rotor portion and the complementary hollow enlarged diameter drum-like and Vee-shaped housing portion with said space containing a ferrofluid and further including selectively operable magnetic field producing means for producing a plurality of magnetic gaps between the concentrically arrayed projections and their opposing surfaces under magnetic sealing operating conditions;
Dependencies are inferred from the claim text.