WO1998022736A1 - Rotating sealing device - Google Patents
Rotating sealing device Download PDFInfo
- Publication number
- WO1998022736A1 WO1998022736A1 PCT/US1997/020693 US9720693W WO9822736A1 WO 1998022736 A1 WO1998022736 A1 WO 1998022736A1 US 9720693 W US9720693 W US 9720693W WO 9822736 A1 WO9822736 A1 WO 9822736A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- liquid metal
- shaft
- housing
- ring
- rotating
- Prior art date
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16J—PISTONS; CYLINDERS; SEALINGS
- F16J15/00—Sealings
- F16J15/16—Sealings between relatively-moving surfaces
- F16J15/40—Sealings between relatively-moving surfaces by means of fluid
- F16J15/43—Sealings between relatively-moving surfaces by means of fluid kept in sealing position by magnetic force
Definitions
- This invention relates to rotating seals between mediums of widely different pressures, and more particularly, to a rotating sealing device for a rotating shaft which extends through a housing wall of a vacuum tight chamber, preventing gas leakage through the wall.
- rotating shaft to control a mechanism inside a high vacuum chamber, such as a rotating anode
- Still another approach to solve the above-mentioned problem was to utilize a magnetic fluid as a sealing element, whereby the magnetic fluid was formed into rings between a shaft housing and a rotatable shaft.
- the conventional magnetic fluid consists of an oil with colloidal magnetic particles suspended in it.
- the liquid rings are maintained between the shaft and the housing by a series of permanent magnets.
- the system is also limited to operations at relatively low temperatures since the vapor pressure of the magnetic fluid increases rapidly with temperature increases.
- At least one ring of a liquid metal between the rotating shaft and its housing incorporated to the wall comprises a liquid metal seal having a shield adjacent to the liquid metal which is placed within one of the mediums at higher pressure for prevention of contamination of the liquid metal seal by gases
- the liquid metal should have a very low solubility for most gases and
- liquid metal may be, for example, gallium, a gallium eutectic or other alloys of gallium.
- the liquid metal seal should be protected from contamination by a magnetic fluid or an oil, such as a silicon oil, which are used as a barrier to water vapor which in combination with oxygen can
- an inert gas may be used to isolate gallium
- liquid metal or metal alloy of the liquid metal seal from reactive gases.
- Fig. 1 is a schematic cross-sectional illustration of a rotating sealing device according to a first embodiment of this invention utilizing a ring of liquid gallium and a ring of oil.
- Fig. 2 is a schematic cross-sectional illustration of another rotating sealing device
- Fig. 3 is a schematic cross-sectional illustration of still another rotating sealing device according to a third embodiment of this invention using a combination of a liquid metal seal and a magnetic fluid seal.
- Fig. 4 is a schematic cross-sectional illustration of still another rotating sealing device according to a fourth embodiment of this invention utilizing a combination of a liquid metal seal
- Fig. 5 is a schematic cross-sectional illustration of still another rotating sealing device
- FIG. 1 which illustrates rotating sealing device 10 according to a first
- rotating shaft 12 penetrates vacuum enclosure 100, extending
- the lower pressure region 102 may be at a pressure
- Shaft 12 has hollow cylindrical housing 14 therearound which is secured to
- Ball bearings 16 are provided to permit rotation of shaft 12 around its own axis while preventing the longitudinal motion of shaft 12 along its axis.
- Ring of liquid metal 18, such as liquid gallium, is contained in a gap between an outer surface of shaft 12 and inner surface of hollow cylindrical housing 14.
- Liquid gallium like many other liquid metals which can be used for sealing the gap
- nonmagnetic liquid metal 18 is maintained along the axis of shaft 12 due to its surface tension
- rings 20 are connected to the material which is wetted by the liquid metal.
- rings 20 are connected to the material which is wetted by the liquid metal.
- rings 21 are made of a material not wetted by liquid metal are incorporated on the inner surface of housing 14 and the outer surface of shaft 12 for suspending ring of liquid
- Rings 21 are made of a material wet by the liquid metal. Rings 20 and 21 may be
- Gallium wets such metals as clean tungsten and molybdenum, and
- rings 18 may comprise gallium or its alloys. In the preferred embodiment gallium is chosen due to its very low vapor pressure,
- housing 14 in wet hydrogen or dissociated ammonia at 1000-1 HOE C for 20 minutes one
- a protective barrier is provided in the form of a ring of silicon oil 22 which has extremely low solubility for water or oxygen. Ring of oil 22 is contained in the
- Fig. 2 shows rotating sealing device 110, according to a second embodiment of the present invention, between rotating shaft 112 which penetrates vacuum wall 100 separating
- hollow cylindrical housing 114 attached to wall 100 surrounds shaft 112 with a narrow gap
- ⁇ is the coefficient of surface tension and d is a distance defining the gap between the outer surface of the shaft and the inner surface of the hollow housing.
- P 2 is the additional pressure caused by gravity acting on the head of the liquid metal and P 3 is the additional pressure caused by the centrifugal force of the liquid metal due to the angular rotation of the shaft.
- g is the acceleration of gravity
- D is the diameter of the shaft.
- Rotating sealing device 110 according to the second embodiment of this invention has
- Circulating ring of silicon oil 122 is used
- drying tank 126 may contain a drying agent
- Spiral grooves 128 formed on the outer surface of shaft 112 may be any suitable material such as sodium metal. Spiral grooves 128 formed on the outer surface of shaft 112 may be any suitable material.
- Oil 122 is protected from leaking out by rings 124 of a fluorinated polymer coating such as Nyebar applied on both shaft 112 and housing 114, as explained with
- Fig. 3 shows rotating sealing device 210, according to a third embodiment of the
- This embodiment provides a combination of a magnetic fluid seal, known also as a ferrofluid seal
- Magnetic fluid 234 is captured and retained in these gaps by the
- Each ring of magnetic fluid 234 is capable of supporting various pressure difference
- the gap widths depending upon the field strength in the gaps, the gap widths and the type of magnetic fluid.
- the rotating sealing device comprises at least five such rings which are formed in tandem to hold off a total pressure difference of one atmosphere.
- Liquid metal protects region 102 against gases that dissolve in magnetic fluid 234 since these gases can diffuse through magnetic fluid 234 to lower pressure region 102 and are desorbed, especially during rotation of shaft 212, the gas transfer
- the of the magnetic fluid is typically 10 '8 Torr at lOOE C and increases rapidly with the temperature
- three-piece rings 220 comprise a nonwetting material and central pieces 223 are made of a
- liquid metal 218 consists of liquid gallium, outer pieces 222 and 224
- central pieces 223 may consist of molybdenum.
- Fig. 4 shows rotating sealing device 310, according to a fourth embodiment of the invention. Seal 310 is positioned between rotating shaft 312 which penetrates wall 100
- housing 314 attached to wall 100, surrounds shaft 312 with a narrow gap therebetween, and
- ball bearings 316 are provided to permit rotation of shaft 312 around its axis while preventing its longitudinal motion.
- a plurality of liquid metal sealing rings 318 are placed in tandem between shaft 312 and housing 314, held in positions along the axis of shaft 312 by providing wetting portions 322 and nonwetting portions 320.
- two magnetic fluid sealing rings 334 are provided in a manner similar to the description given with reference to Fig. 3 with
- Getter pump 350 is used for absorbing or trapping any reactive gases
- Fig. 5 shows rotating sealing device 410, according to a fifth embodiment of the invention, which is placed between rotating shaft 412 that penetrates vacuum wall 100
- Hollow cylindrical housing 414 attached to wall 100, surrounds shaft 412 with a narrow gap therebetween, and
- ball bearings 416 are provided to permit rotation of shaft 412 around its axis while preventing
- liquid metal sealing rings 418 are placed in tandem between shaft 412 and housing 414, suspended in positions along the axis of shaft 412 by providing wetting regions 422 and nonwetting regions 420. In order to protect liquid metal sealing rings 418 from
- Ring seal 476 is provided between shaft 412 and
- housing 414 to prevent excessive gas loss.
- inert gas which may be used in this specification
- the gas may be provided from a high-pressure container through a flow regulator (not shown) of a known kind and in a known manner.
Landscapes
- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Sealing Using Fluids, Sealing Without Contact, And Removal Of Oil (AREA)
Abstract
Description
Claims
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CA002244678A CA2244678C (en) | 1996-11-21 | 1997-11-05 | Rotating sealing device |
EP97948267A EP0876563A1 (en) | 1996-11-21 | 1997-11-05 | Rotating sealing device |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US08/754,946 US5799951A (en) | 1996-11-21 | 1996-11-21 | Rotating sealing device |
US08/754,946 | 1996-11-21 |
Publications (2)
Publication Number | Publication Date |
---|---|
WO1998022736A1 true WO1998022736A1 (en) | 1998-05-28 |
WO1998022736A9 WO1998022736A9 (en) | 1998-09-11 |
Family
ID=25037065
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/US1997/020693 WO1998022736A1 (en) | 1996-11-21 | 1997-11-05 | Rotating sealing device |
Country Status (4)
Country | Link |
---|---|
US (1) | US5799951A (en) |
EP (1) | EP0876563A1 (en) |
CA (1) | CA2244678C (en) |
WO (1) | WO1998022736A1 (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7657014B2 (en) | 1997-11-04 | 2010-02-02 | At&T Intellectual Property I, L.P. | Call screening method and apparatus |
WO2013175335A1 (en) * | 2012-05-22 | 2013-11-28 | Koninklijke Philips N.V. | X-ray tube rotor with carbon composite based material |
Families Citing this family (16)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0966019B1 (en) * | 1998-06-19 | 2004-04-28 | Koyo Seiko Co., Ltd. | Rotating anode x-ray tube capable of efficiently discharging intense heat |
US6543782B1 (en) * | 2001-04-11 | 2003-04-08 | Ferrotec (Usa) Corporation | Non-bursting ferrofluid seal |
US6845986B2 (en) | 2002-04-26 | 2005-01-25 | Stemco Llc | Low torque seal assembly |
US6899338B2 (en) * | 2003-03-06 | 2005-05-31 | Ferrotec Usa Corporation | Ferrofluid seal incorporating multiple types of ferrofluid |
US7736817B2 (en) * | 2003-09-30 | 2010-06-15 | Hewlett-Packard Development Company, L.P. | Method of forming an interface between components having different rates of expansion |
US7197115B2 (en) * | 2004-08-10 | 2007-03-27 | General Electric Company | Cantilever and straddle x-ray tube configurations for a rotating anode with vacuum transition chambers |
JP4885490B2 (en) * | 2005-06-30 | 2012-02-29 | 株式会社リガク | Magnetic fluid seal device |
US20070138747A1 (en) * | 2005-12-15 | 2007-06-21 | General Electric Company | Multi-stage ferrofluidic seal having one or more space-occupying annulus assemblies situated within its interstage spaces for reducing the gas load therein |
CN100360839C (en) * | 2006-08-01 | 2008-01-09 | 中国兵器工业第五二研究所 | Magnetic liquid sealing device |
KR100748179B1 (en) * | 2006-11-09 | 2007-08-09 | 손규태 | Throttle valve having structure of magnetic fluid seal |
CN101377985B (en) * | 2007-08-31 | 2012-08-22 | 湖南维格磁流体股份有限公司 | Dynamic sealing device for middle/high voltage power switchgear |
US20090066033A1 (en) * | 2007-09-11 | 2009-03-12 | General Electric Company | Barrier sealing system |
US9322478B2 (en) * | 2012-07-31 | 2016-04-26 | General Electric Company | Seal system and method for rotary machine |
JP5933399B2 (en) * | 2012-09-07 | 2016-06-08 | 東京エレクトロン株式会社 | Heat treatment equipment |
TWI616555B (en) * | 2017-01-17 | 2018-03-01 | 漢民科技股份有限公司 | Gas injectorused for semiconductor equipment |
EP3575641A1 (en) * | 2018-05-30 | 2019-12-04 | Siemens Aktiengesellschaft | Arrangement, in particular turbomachine, comprising a shaft seal arrangement |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3502342A (en) * | 1967-12-01 | 1970-03-24 | Singer General Precision | Face type liquid metal seal and method of making the same |
GB1518583A (en) * | 1976-03-09 | 1978-07-19 | Teplotekh Nii Im Fe Dzerzhin V | Sealed assembly |
EP0023993A1 (en) * | 1979-08-14 | 1981-02-18 | Westinghouse Electric Corporation | Face type shaft seal for liquid metal pumps |
US4605233A (en) * | 1982-09-16 | 1986-08-12 | Rigaku Keisoku Kabushiki Kaisha | Magnetic fluid sealing device |
Family Cites Families (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2678835A (en) * | 1946-02-08 | 1954-05-18 | Us Navy | Rotating joint |
US3038731A (en) * | 1958-03-14 | 1962-06-12 | Milleron Norman | Vacuum sealing means for low vacuum pressures |
US3620584A (en) * | 1970-05-25 | 1971-11-16 | Ferrofluidics Corp | Magnetic fluid seals |
US3778123A (en) * | 1971-11-17 | 1973-12-11 | Singer Co | Liquid bearing unit and seal |
US4485628A (en) * | 1982-12-06 | 1984-12-04 | Dedger Jones | High temperature engine and seal |
US4407518A (en) * | 1983-01-05 | 1983-10-04 | Ferrofluidics Corporation | Nonbursting multiple-stage ferrofluid seal and system |
US4577340A (en) * | 1983-09-19 | 1986-03-18 | Technicare Corporation | High vacuum rotating anode X-ray tube |
NL8801925A (en) * | 1988-08-02 | 1990-03-01 | Skf Ind Trading & Dev | SEALING ASSEMBLY WITH A MAGNETIC LIQUID. |
US5472215A (en) * | 1994-03-21 | 1995-12-05 | The United States Of America As Represented By The Secretary Of The Army | Rotating high vacuum mercury seal |
-
1996
- 1996-11-21 US US08/754,946 patent/US5799951A/en not_active Expired - Fee Related
-
1997
- 1997-11-05 EP EP97948267A patent/EP0876563A1/en not_active Withdrawn
- 1997-11-05 WO PCT/US1997/020693 patent/WO1998022736A1/en not_active Application Discontinuation
- 1997-11-05 CA CA002244678A patent/CA2244678C/en not_active Expired - Fee Related
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3502342A (en) * | 1967-12-01 | 1970-03-24 | Singer General Precision | Face type liquid metal seal and method of making the same |
GB1518583A (en) * | 1976-03-09 | 1978-07-19 | Teplotekh Nii Im Fe Dzerzhin V | Sealed assembly |
EP0023993A1 (en) * | 1979-08-14 | 1981-02-18 | Westinghouse Electric Corporation | Face type shaft seal for liquid metal pumps |
US4605233A (en) * | 1982-09-16 | 1986-08-12 | Rigaku Keisoku Kabushiki Kaisha | Magnetic fluid sealing device |
Non-Patent Citations (1)
Title |
---|
N.MILLERON: "Utilization of the surface tension of liquid metals in making high-vacuum seals", W.G. MATHESON:TRANSACTIONS OF THE AMERICAN VACUUM SOCIETY SYMPOSIUM, 9 October 1957 (1957-10-09), BOSTON, pages 38 - 41, XP002059645 * |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7657014B2 (en) | 1997-11-04 | 2010-02-02 | At&T Intellectual Property I, L.P. | Call screening method and apparatus |
WO2013175335A1 (en) * | 2012-05-22 | 2013-11-28 | Koninklijke Philips N.V. | X-ray tube rotor with carbon composite based material |
US9853511B2 (en) | 2012-05-22 | 2017-12-26 | Koninklijke Philips N.V. | X-ray tube rotor with carbon composite based material |
Also Published As
Publication number | Publication date |
---|---|
CA2244678C (en) | 2003-06-03 |
US5799951A (en) | 1998-09-01 |
EP0876563A1 (en) | 1998-11-11 |
CA2244678A1 (en) | 1998-05-28 |
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