EP0394452A1 - Pompe d'adsorption cryogenique - Google Patents

Pompe d'adsorption cryogenique Download PDF

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Publication number
EP0394452A1
EP0394452A1 EP89903490A EP89903490A EP0394452A1 EP 0394452 A1 EP0394452 A1 EP 0394452A1 EP 89903490 A EP89903490 A EP 89903490A EP 89903490 A EP89903490 A EP 89903490A EP 0394452 A1 EP0394452 A1 EP 0394452A1
Authority
EP
European Patent Office
Prior art keywords
pump
vessel
heat
frame
adsorbent
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP89903490A
Other languages
German (de)
English (en)
Other versions
EP0394452A4 (en
Inventor
Marxen Petrovich Larin
Maxim Leonidovich Alexandrov
Valery Ivanovich Nikolaev
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
NAUCHNO-TEKHNICHESKOE OBIEDINENIE AKADEMII NAUK SSSR
Original Assignee
NAUCHNO-TEKHNICHESKOE OBIEDINENIE AKADEMII NAUK SSSR
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by NAUCHNO-TEKHNICHESKOE OBIEDINENIE AKADEMII NAUK SSSR filed Critical NAUCHNO-TEKHNICHESKOE OBIEDINENIE AKADEMII NAUK SSSR
Publication of EP0394452A1 publication Critical patent/EP0394452A1/fr
Publication of EP0394452A4 publication Critical patent/EP0394452A4/de
Withdrawn legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B37/00—Pumps having pertinent characteristics not provided for in, or of interest apart from, groups F04B25/00 - F04B35/00
    • F04B37/06—Pumps having pertinent characteristics not provided for in, or of interest apart from, groups F04B25/00 - F04B35/00 for evacuating by thermal means
    • F04B37/08—Pumps having pertinent characteristics not provided for in, or of interest apart from, groups F04B25/00 - F04B35/00 for evacuating by thermal means by condensing or freezing, e.g. cryogenic pumps
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S417/00—Pumps
    • Y10S417/901—Cryogenic pumps

Definitions

  • the invention relates to vacuum technology and in particular to cryogenic adsorption pumps and can be used to generate an ultra-pure oil-free vacuum in a pressure range of 10 2 to 10- 7 Pa when evacuating any gases, except helium, including more aggressive, in chambers of various purposes with a volume of 0.01 m 3 can be used up to several hundreds of cubic meters.
  • cryogenic adsorption pump with a pumping element known (SU, A, 1333833), which consists of an annular vessel with liquid nitrogen, a porous screen, which is arranged coaxially with the vessel in a space which is enclosed by the inner side surface of the vessel , and an adsorbent, which is housed in a gap between the inner side surface of the vessel and the porous screen.
  • a disadvantage of this pump is that at the liquid nitrogen temperature the adsorbent has a low sorption capacity at low (below 10 -3 - 10 -4 Pa) equilibrium pressures of the adsorbable gases. Therefore, the pump cannot achieve limit pressures below 10- 3 Pa even after a brief gas exposure.
  • the adsorbent is cooled by solid nitrogen up to a temperature of 55-50 K.
  • a cryogenic adsorption pump is also known (Zhurnal tekhniche.skoi fiziki, Volume 28, Issue 10, 1988, October, Nauka (Leningrad branch), MP Larin "Kondatsatsionno-adsorptsionnaya i sorbtsionnaya otkachka pri Temperaturakh twerdogo azota", pp. 2026 to 2039) with a housing with a cover , which is provided with an inlet connection for connecting a volume to be evacuated, and the housed in the housing a pumping element and a cooled radiation shield, which surrounds the pumping element.
  • the pumping element is designed as a ring-shaped vessel for cryogenic agents and contains the perforated heat-conducting frames and frame-porous screens arranged coaxially therewith in a space which is delimited by the inner vessel wall.
  • the Gafäßêt, the heat-conducting frames and the frame-porous screens are welded to a disc-shaped heat conductor, so that a thermal contact between the vessel and the heat-conducting frames is ensured.
  • Two frame-porous screens are arranged on both sides of the vessel walls and the other on both sides of the heat-conducting frames, annular spaces between the vessel walls and the frame-porous screens, as well as annular spaces between the heat-conducting frames and the frame-porous screens closest to them are filled with adsorbents . From above, the rooms are covered by rings. Annular cavities between adjacent frames - porous screens are connected to the inlet connection of the pump.
  • the cryogen container has an annular lid with two tubes, with the help of which cryogen is filled into the container and its vapors are evacuated. The upper ends of these tubes are attached to the housing cover.
  • the adsorbent In order to increase the adsorption capacity of a pump, which is one of the most essential pumping characteristics of the pump, the adsorbent should occupy as large a volume as possible in the present pump dimensions and to increase the effectiveness of the pump the surface of the adsorbent and the porous screens should be as large as possible.
  • cavities are enclosed with an adsorbent through the vessel of the pumping element, with the exception of an outer cavity which is connected to the outer side surface of the vessel.
  • the cryogen container takes up a relatively large volume of the pumping element, which has no direct participation in the pumping process, although it could accommodate adsorbents and porous screens.
  • the outer cavity surrounding the vessel with adsorbent As for the outer cavity surrounding the vessel with adsorbent, it has a low effectiveness due to the low conductivity of a play between it and a radiation screen. From DIE 'sem reasons said cryogenic pump has only an insufficient effect of sorption capacity or speed.
  • the invention has for its object to provide a cryogenic adsorption pump, in the pumping element thermally conductive frames and frame-porous screens with respect to the vessel for cryogen which cools an adsorbent located in cavities between the said frames are arranged so that the volume of these Cavities and the surface of the frame-porous screens are increased, as a result of which the adsorption capacity of the pump and its effectiveness are increased.
  • the diameter of the heat-conducting frames and the frame-porous screens can be increased, which increases the surface area of the porous screens and consequently the speed of action of the pump.
  • the diameter of the heat-conducting frames and the frame-porous screens is increased, the volume of the cavities is also increased with an adsorbent, ie the amount thereof, which increases the sorption capacity of a pump.
  • cryogenic adsorption pump according to the invention is shown in longitudinal section.
  • the cryogenic adsorption pump has a housing 1 with a cover 2, which is provided with an inlet connection 3.
  • a pumping element which contains a toroidal cryogen container 4, on the cover 5 of which coaxially arranged heat-conducting frames 6, 7, 8 and frame-porous screens 9 are welded.
  • the outer 6 and the inner 8 heat-conducting frame are made of a dense sheet material and other heat-conducting frames 7 are perforated. Porous copper, for example, can be used as the material for the frames 9.
  • the outer porous screen 9 is on the inside of the heat-conducting frame 6, 'the inner porous screen on the outside of the heat-conducting frame 8 and the other porous screens 9 are arranged on both sides of the perforated heat conductor 7.
  • Annular spaces 10 between the heat-conducting frames 6, 7, 8 and the porous screens 9 adjoining them are filled with an adsorbent, for example with activated carbon.
  • a perforation in the heat conductors 7, which are surrounded by adsorbents from the two sides, is to accelerate a compensation operation of the equilibrium gas pressure carried out over the adsorbent.
  • the cavities "10 are covered from above by rings 11.
  • Annular spaces 12 between adjacent porous screens 9 serve to pass through the evacuated gases.
  • tubes 13 are welded airtight, which are connected to its cavity.
  • the upper ends of these tubes 13 are led out of the housing 1 and fastened in its cover 2 with the aid of connecting pieces 14.
  • the tubes 13 are used for filling the cryogen in the vessel 4 and for evacuating the cryogen vapors to lower the cryogen temperature in the vessel 4.
  • the pumping element is enclosed by a radiation shield to reduce the supply of heat by radiation from the housing 1.
  • the radiation shield contains a toroidal cryogenic agent vessel 15, a frame 16 and an arrow screen 17.
  • the vessel 4 of the pumping element is arranged, and frame 16 is attached to the vessel 15 in an airtight manner at its lower part.
  • two tubes 18 and 19 are inserted, of which the tube 18 is used for filling the cryogen in the vessel 15 and the tube 19 for the escape of the cryogen vapors.
  • the frame 16 has a cover 20 which is connected to the inlet connection 3 via a thermal bridge 21 designed as a corrugated tube.
  • Sockets 22 are welded to the cover 20 of the frame 16, the upper ends of which are welded to the tubes 13 and the stubs 14 in a vacuum-tight manner.
  • the arrow screen 17 is arranged between the pumping element and the inlet connection and is fastened to the upper part of the frame 16 with good thermal contact.
  • a thin-walled tube 23 is arranged in the interior of the vessel 15 of the radiation shield, the lower end of which is welded to a flange 24, which is fastened to the bottom 25 of the housing 1, and the upper end to the lid of the vessel 15, the cross section of the tube 23 covered in its upper part by an arrow screen 26.
  • This cavity 27 can be evacuated via a nozzle 28, which can be arranged, for example, on the bottom 25 of the housing 1. So that a required vacuum level is maintained in the cavity 27 in the operating state, the frame 16 has an annular recess 29 with adsorbent, which is covered by a porous screen 30.
  • An additional screen 31 is arranged between the housing 1 and the radiation shield, which reduces the supply of heat by radiation from the housing 1 to the radiation shield.
  • nozzles 32 On a side wall of the inlet nozzle 3 there are two nozzles 32, one of which is used to connect a backing pump via a valve and the other is used to connect a manometric transducer to control a vacuum level in the inlet nozzle 3.
  • discs 33 and 34 with openings 35 and 36 are arranged along the axis thereof, and the arrow screens 17 and 26 have openings 37 and 38 for gripping through a transport rod, which with the aid of a threaded connection in the opening 36 of the disc 34 and in blind flanges 39, 40 is attached.
  • All surfaces of the pump elements with the exception of surfaces of the arrow screens 17 and 26, which face the volume to be evacuated, have a two-layer coating made of a dense aluminum layer with a thickness of not less than 1 ⁇ m and an aluminum oxide layer with a thickness of 2 to 20 nm.
  • the arrow screens 17 and 26 have a coating with a .thickness not less than 150 microns with a degree of blackening not less than 0.99 in a wavelength range 2 to 200 microns.
  • the pump according to the invention works as follows.
  • a working chamber to be evacuated (not shown) is connected to the inlet connection 3 directly or via a closure (not shown).
  • a mechanical (not shown) fore-vacuum pump is closed on the nozzle 28 via a valve (not shown) with a metal seal and the protective vacuum chamber 27 is evacuated until a pressure of approx. 100 to 40 Pa is achieved therein becomes.
  • a cryogen for example liquid nitrogen, is filled into the vessel 15 of the radiation shield via the tube 18.
  • the adsorbent which is located in the annular recess 29 of the frame 16, also cools, which results in a pressure drop in the space 27 of up to 10 -4 to 10- 5 Pa and below and a strong reduction in heat exchange by residual gases caused between the housing 1 and the radiation shield.
  • cryogen which has a temperature below that of the cryogen in the vessel 15, e.g. Liquid hydrogen or helium, or the same cryogen, e.g. Liquid nitrogen.
  • the cryogen temperature in the vessel 4 is reduced by evacuating the cryomite vapors with the aid of the mechanical forevacuum pump which is connected to the pipes 13.
  • the backing pump e.g. 16 l / s after two hours of operation, the temperature of the frozen nitrogen is reduced to about 55 K and after another four hours up to 50 K and below.
  • the heat conductors 6, 7 and 8 cool the adsorbent which is located in annular cavities 10 of the pumping element.
  • Adsorbent swallows the gases coming out of the working chamber and ensures a limit pressure of 10 -7 Pa and below.
  • a temperature of the adsorbent of approximately 50 K its sorption capacity increases by several orders of magnitude in comparison with that at a temperature of 77.4 K, ie an equilibrium pressure is reduced by 3 to 4 orders of magnitude after adsorption of one and the same amount of gas.
  • the pump is ready for operation and the working chamber can be evacuated.
  • Non-adsorbable gases (helium, neon) are generated with the help of an ion atomizing pump (not shown) removed, which is connected to the flange 24.
  • cavities 10 with adsorbent are distributed over the practically entire cross section of the pump in an area which is enclosed by the frame 16 of the radiation screen, the entire surface of the porous screens 9, the volume of the cavities 10 with adsorbent and the cross-sectional area of the cavities 12 enlarged to flow through the evacuated gases between the adjacent porous screens 9.
  • the effectiveness of the pump with the construction according to the invention is approximately 30% and its sorption capacity is approximately 15% in comparison with the known pump (Zhurnal tekhnicheskoi fiziki, Volume 58, Issue 10, 1988, October, Nauka (Leningrad branch) MP Larin "Kondensatsionno-adsorbtsionnaya i sorbtsionnaya otkachka pri Temperaturakh tverdogo azota", pp. 2026 to 2039) with the same dimensions with this pump.
  • An additional advantage of the invention which is due to the arrangement of the heat pipes 6, 7, 8 and the porous screens 9 on the lid 5 of the vessel 4 of the pumping element, is that the tubes 13 of the vessel 4 have a greater length than in the known one Pump, as a result, heat input through them into the vessel 4 is reduced. So that the required speed when sucking the nitrogen vapors from the vessel 4 is ensured, the through. Knife of the tubes 13 are enlarged.
  • the invention can be used for evacuating plants for vapor deposition and plasma-chemical plants, for example in the electronics industry, and for producing an ultra-pure oil-free vacuum in a pressure range from 10 2 to 10 -7 Pa when solving several tasks in vacuum technology.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Compressors, Vaccum Pumps And Other Relevant Systems (AREA)
  • Nitrogen And Oxygen Or Sulfur-Condensed Heterocyclic Ring Systems (AREA)
  • Structures Of Non-Positive Displacement Pumps (AREA)
  • Filling Or Discharging Of Gas Storage Vessels (AREA)

Abstract

Dans l'élément d'aspiration de la pompe d'adsorption cryogénique, l'agent adsorbant est disposé dans les chambres annulaires (10) situées entre des enveloppes thermoconductrices (6, 7, 8) et des enveloppes à écran poreux (9), les enveloppes (6, 7, 8, 9) étant fixées de façon à assurer un contact thermique avec le couvercle (5) du réservoir (4) de l'agent cryogénique.
EP19890903490 1988-03-10 1989-02-10 Cryogenic adsorption pump Withdrawn EP0394452A4 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SU4391234 1988-03-10
SU884391234A SU1682628A1 (ru) 1988-03-10 1988-03-10 Криоадсорбционный насос

Publications (2)

Publication Number Publication Date
EP0394452A1 true EP0394452A1 (fr) 1990-10-31
EP0394452A4 EP0394452A4 (en) 1991-01-23

Family

ID=21360806

Family Applications (2)

Application Number Title Priority Date Filing Date
EP19890903491 Withdrawn EP0363497A4 (en) 1988-03-10 1989-02-10 Cryogenic adsorption pump
EP19890903490 Withdrawn EP0394452A4 (en) 1988-03-10 1989-02-10 Cryogenic adsorption pump

Family Applications Before (1)

Application Number Title Priority Date Filing Date
EP19890903491 Withdrawn EP0363497A4 (en) 1988-03-10 1989-02-10 Cryogenic adsorption pump

Country Status (6)

Country Link
US (2) US4979369A (fr)
EP (2) EP0363497A4 (fr)
JP (2) JPH02503462A (fr)
AU (2) AU623387B2 (fr)
SU (1) SU1682628A1 (fr)
WO (2) WO1989008780A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5400604A (en) * 1990-11-19 1995-03-28 Leybold Ag Cryopump and process for regenerating said cryopump

Families Citing this family (11)

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Publication number Priority date Publication date Assignee Title
SU1682628A1 (ru) * 1988-03-10 1991-10-07 Институт Аналитического Приборостроения Научно-Технического Объединения Ан Ссср Криоадсорбционный насос
US5261244A (en) * 1992-05-21 1993-11-16 Helix Technology Corporation Cryogenic waterpump
AT398849B (de) * 1992-09-08 1995-02-27 Sitte Hellmuth Kammer zur gefriertrocknung durch kryosorption
US5537833A (en) * 1995-05-02 1996-07-23 Helix Technology Corporation Shielded cryogenic trap
US5799493A (en) * 1996-09-05 1998-09-01 Helix Technology Corporation Corrosion resistant cryopump
US6154478A (en) * 1998-06-30 2000-11-28 The Boeing Company Chemical oxygen-iodine laser (coil)/cryosorption vacuum pump system
US6650681B1 (en) 2000-04-25 2003-11-18 The Boeing Company Sealed exhaust chemical oxygen-iodine laser system
US6621848B1 (en) 2000-04-25 2003-09-16 The Boeing Company SECOIL reprocessing system
US6438992B1 (en) * 2000-10-18 2002-08-27 Thermal Products Development, Inc. Evacuated sorbent assembly and cooling device incorporating same
US7320224B2 (en) * 2004-01-21 2008-01-22 Brooks Automation, Inc. Method and apparatus for detecting and measuring state of fullness in cryopumps
US20070051242A1 (en) * 2005-09-08 2007-03-08 Petrik Viktor I Configurations and methods for assisted condensation

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SU1682628A1 (ru) * 1988-03-10 1991-10-07 Институт Аналитического Приборостроения Научно-Технического Объединения Ан Ссср Криоадсорбционный насос

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Title
KEINE WEITERE DOKUMENTEN ERMITTELT. *
See also references of WO8908781A1 *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5400604A (en) * 1990-11-19 1995-03-28 Leybold Ag Cryopump and process for regenerating said cryopump

Also Published As

Publication number Publication date
US4979369A (en) 1990-12-25
US5014517A (en) 1991-05-14
WO1989008780A1 (fr) 1989-09-21
WO1989008781A1 (fr) 1989-09-21
SU1682628A1 (ru) 1991-10-07
EP0363497A1 (fr) 1990-04-18
AU3286389A (en) 1989-10-05
JPH02503461A (ja) 1990-10-18
AU615342B2 (en) 1991-09-26
AU4188589A (en) 1989-10-05
EP0394452A4 (en) 1991-01-23
JPH02503462A (ja) 1990-10-18
EP0363497A4 (en) 1991-01-23
AU623387B2 (en) 1992-05-14

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