US3579997A - Cryopumping installations with high flow-rates - Google Patents

Cryopumping installations with high flow-rates Download PDF

Info

Publication number
US3579997A
US3579997A US840734A US3579997DA US3579997A US 3579997 A US3579997 A US 3579997A US 840734 A US840734 A US 840734A US 3579997D A US3579997D A US 3579997DA US 3579997 A US3579997 A US 3579997A
Authority
US
United States
Prior art keywords
cryopump
high flow
flow rate
casing
cold fluid
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.)
Expired - Lifetime
Application number
US840734A
Other languages
English (en)
Inventor
Michel Rapinat
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.)
Air Liquide SA
LAir Liquide SA pour lEtude et lExploitation des Procedes Georges Claude
Original Assignee
Air Liquide SA
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 Air Liquide SA filed Critical Air Liquide SA
Application granted granted Critical
Publication of US3579997A publication Critical patent/US3579997A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

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

Definitions

  • a cryopump is constituted by a fluidtight casing inside which is arranged a plurality of condensation plates carried by a cooling coil supplied with very cold fluid, the whole disposed externally of and around a baffle formed by a plurality of frustoconical rings arranged in the extension of a stop valve.
  • the baffle is preferably cooled by a moderately cold fluid (80K) though conduits, while a coil embedded in the wall of the casing and traversed by a moderately cold fluid cools an internal wall of the casing.
  • This cryopumping device is adapted to extract high flow rates at a relatively moderate pressure of theorder of l0l2 torr.
  • the present invention relates to improvements in cryopumping installations with high flow rates, and in particular to such installations which can operate continuously up to moderately high vacua, of the order of lOz torr, for example.
  • cryopumps by means of which a vacuum can be obtained and then maintained in a chamber, the gas coming from the chamber to be exhausted is deposited in the solid state on collecting means, constituted for example by a condensation or sublimation surface cooled by the vapors of a liquefied gas or by a refrigerator working in a closed circuitA
  • collecting means constituted for example by a condensation or sublimation surface cooled by the vapors of a liquefied gas or by a refrigerator working in a closed circuitA
  • cryopumps have been especially utilized for ultravacua, that is to say for high vacua which may attain 1019 tori'A ln this case, the mass flow is very low and the thickness of the condensate always remains small, even if the condensation surface is relatively modest, and although this type of cryopump may be in operation for long periods in order to maintain a very high vacuum, such continuous working does not present any problems since it is not necessary to carry out regeneration operations.
  • the ultravacuum cryopumps constructed at the present time are thus characterized by thc existence of a single pumping element or unit, and by condensation walls having a relatively modest surface area.
  • the high value of the mass flow of gas to be cryopumped necessitates the production of a pumping unit which has at the same time a good inlet conductance for the gases to be collected and a large condensation surface area, and it is an object ofthe invention to provide a cryopump in which these two characteristics are arranged so as to obtain satisfactory operation of the pump with however a comparatively small overall size.
  • the collecting means comprise main collecting means brought to a cold temperature, arranged outside and around a baffle brought to a moderately cold temperature and constituted by an assembly of walls of revolution arranged at a distance from each other along a common axis forming an extension of the axis of the inlet valve, and having an internal diameter substantially in the vicinity of that of the said inlet valve.
  • the baflle is a body composed of a plurality of deflecting walls, for example of frustoconical shape, arranged at a distance from each other along a common axis and permitting a radial distribution in steps towards the exterior of the gas which passes into the interior of the baffle, while forming a screen against direct radiation coming from the zone at ambient temperature, that is to say in the present case, essentially from the inlet valve.
  • the cross section of passage of the baffle that is to say the sum of the individual sections between two frustoconical walls, is independent of the diameter of the valve, and it can easily be increased by providing a larger number of baffle walls, or in other words by extending the cryopump axially. lt is thus possible to obtain a very high inlet conductance of the gases in the direction of the main condensation surface.
  • the surface area of the condensation wall may be very large, since the latter surrounds the baffle. Furthermore, a small increase in external diameter is sufficient to produce a very large increase in the exchange surfaces.
  • the regeneration of one cryopump unit is effected by introducing into the chamber a certain flow of hot gas which, by cooling and becoming liquefied, causes the sublimation or the liquefaction of the deposit.
  • This method of regeneration is very simple, very rapid and permits good recovery of frigories.
  • FIG. l is a diagrammatic view of the whole of a cryopumping installation
  • FIG. 2 is a view in cross section of a pumping unit according to the invention.
  • cryopump which can operate without interruption for several months, and which is capable of pumping a large mass flow at a pressure of l0l2 torr.
  • the installation according to the invention is composed of a cryogenerator l, two pumping units 2 and 3 and accessories permitting continuous working to be effected.
  • the cryogenerator l produces a certain frigorific output at two temperature levels, which are respectively in the vicinity of 80 K and 25 K.
  • the frigories produced by the cryogenerator are conveyed to the pumping units by means of a circulation of two fluxes of gaseous helium under pressure, respectively through the outward and return conduits 4 and S with stop valves 6 and 7 for the very cold fluid (25 K) and outward and return conduits 8 and 9 for the moderately cold fluid (80 l() towards the two pumping units 2 and 3, which are connected by the isolating valves 13 and 14 respectively to a chamber l2 in which a vacuum is to be maintained.
  • each pumping unit 2 (3) is constituted by a fluidtight casing delimited towards the exterior by a wall with high heat insulation 21 composed of two parts 21a, 2lb
  • These plates 22, of which there is a very large number, are for example square with a 5 mm. side, a thickness of.l mm. and spaced apart by 3 cm.
  • On each side of the plates 22 arev arranged, on one side a wall 25 fixed against the internal face of the wall of the casing 21a; on the other side a baffle 26, cornposed of a plurality of frustoconical rings 26a, 26b, 26e, 26d, arranged coaxially with the vertical axis of the casing in the extension of the axis of the isolating valve (13 (14) and flared upwards.
  • These rings 26a, 26h, 26e, 26d are blackened so as to prevent reflection of the radiation produced by the surfaces at ambient temperature (especially the valves ll3 (14).
  • the lower ring 26d is followed by a conical reflector 27, the apex of which is directed upwards.
  • These rings forming the baffle 26, the reflector 27, and also the walls 2S are supplied with fairly cold fluid by a cooling coil, constituted, level with the baffle 26, by a plurality of con duits in the form of open rings 30a, 30b, 30C, 30d, the downstream extremity of one being connected to the upstream extremity of ⁇ the next following ring byva pillar element 28a, 28h, 23e, 28d, this latter supplying a ring 31 level with the reflector 27, while the return is effected by the conduit 28e and by a coil 32 embedded in the wall 2S, both supplied by the conduits 9 of fairly cold fluid.
  • a cooling coil constituted, level with the baffle 26, by a plurality of con duits in the form of open rings 30a, 30b, 30C, 30d, the downstream extremity of one being connected to the upstream extremity of ⁇ the next following ring byva pillar element 28a, 28h, 23e, 28d, this latter supplying a ring 31 level with the reflector 27, while the return
  • the wall 25 is extended downwards by a bottom collecting wall 29 with a funnel member 35 and having a portion in the form of a dome 34 with one or a number of laterial perforations 33.
  • the installation further comprises accessories which enablethe saturated unit to be regenerated, and which ensure the continuous operation of the installation.
  • These accessories mainly comprise: A pumping group 40 for the noncondensable gases, connected to a conduit 4l, 42, terminating at the bottom of each pumping unit 2, 3, through the intermediary of a valve 43 and 44 respectively.
  • This group 40 is intended to eliminate the gases which are only condensable at a temperature colder than the temperature of the main condensation walls 22 (that is to say colder than 25 K).
  • gases are mainly hydrogen and helium.
  • lt is particularly advisable to utilize a diffusion pump associated with a primary pump, in consequence of the relatively low flow rate of the pressure level (about lI3 torr) and the nature of the gases.
  • a prevacuum pump 45 connected by the conduits 46, 47 to valves 48, 49, in the interior of each unit 2, 3. After each regeneration, the pressure rises in the unit to a fairly high value. Before being able to put this unit back into operation, it is necessary to reduce the pressure to a few torrs. A primary pump is particularly well suited to this use.
  • a receptacle 50 intended to collect the liquefied gases and communicating by a valve with atmospheric air, and into which discharges a pipe 5l connected by the conduits 52, 53 to valves 54 (55), FIG. 2 on the funnel 35 at the bottom of each pumping .unit 2, 3.
  • This receptacle 50 permits the collection of the liquefied deposit during regeneration. It is possible to recover the frigories stored in this tank by immersing in it a coil 56 through which passes the helium coming from the head of fairly cold fluid 8, 9.
  • the regeneration of the pumping unit is effected in the following manner: A regenerated unit 2 (or 3) is put in parallel with the unit 3 (or 2) in course of operation, after which this unit 3 (or 2) respectively, is isolated by the valve 14 (or I3) respectively. The circulation of helium at very low temperature (25 K) is then interrupted to the unit 3 in course of regeneration, by closing the valve 7.
  • valve 55 which puts the unit 3 into communication with the tank 50, is then opened. An inlet of dry atmosphere takes place which causes the liquefaction of the deposit. The liquid obtained is then collected by gravity in this same tank 50.
  • the unit 3 is then isolated from the tank 50 (closure of the valve 55) and is then put into communication with the prevacuum pump 45 by opening the valve 48.
  • the pressure is then brought to a value of a few torrs.
  • the unit is cooled by opening the valve 7, by a small flow of helium at 25 K so as to prepare it for being put into operation,
  • the pumping unit When the temperature of the cryosurface is lower than 30 K, the pumping unit is regenerated and is immediately ready to work.
  • the installation described above, or any other installation derived therefrom, permits the production of a cryopump working continuously and capable of pumping a large mass flow at pressures of the order of l0lz torr. It is possible to contemplate the use of this installation in replacing pumping groups comprising Roots" or steam ejectors. The replacement of the Roots is particularly recommended when the gas to be pumped contains dust.
  • a cryopump with a high flow rate comprising a fluidtight casing thermally insulated from the exterior and having a wide inlet passage, an inlet valve associated with said passage, gas collection meanscomprising baffle means formed by an assembly of walls of annular form mounted at a distance from each other along a common axis in the extension of the axis of said inlet valve, said baffle means having an internal diameter substantially close to that of said inlet passage, main collecting means disposed externally around said baffle, means and means for circulating a moderately cold fluid for said baffle means and a very cold fluid for said main collecting means.
  • a cryopump with a high flow rate as claimed in claim l in which said baffle means comprises a plurality of frustoconical stepped walls, spaced apart from each other.
  • a cryopump with a high flow rate as claimed in claim l in which said means for circulating a very cold fluid comprise a tubular coil mounted round and externally to said baffle, means said main collecting means comprising an assembly of metal plates carried by said coil.
  • a cryopump with a high flow rate as claimed in claim l and further comprising a reflector located at the extremity of said baffle means opposite to said inlet valve, said means for circulating a moderately cold fluid incorporating a tube for cooling said reflector.
  • a cryopump with a high flow rate as claimed in claim l in which an internal wall of said casing is cooled by said means for circulating a moderately cold fluid.
  • a cryopumping installation with a high flow rate cornprising at least two cryopumps each including a fluidtight casing thermally insulated from the exterior and having a wide inlet passage, an inlet valve associated with said passage, gas collection means comprising baffle means formed by an assembly of walls of annular form arranged at a distance from each other along a common axis in the extension of the axis of said inlet valve, said baffle means having an internal diameter substantially close to that of said inlet passage and main collecting means disposed externally of and around said baffle means, means for circulating a moderately cold fluid for said baffle means and a very cold fluid for said main collecting means, a single chamber to be exhausted coupled to each said pump by means of each of said inlet valves, a double flux cryogenerator supplying said means for circulating moderately cold and very cold fluids, stop valves on said circulating means, a pumping group, coupling means incorporating stop valves between said pumping group and each said cryopump,
  • a cryopump with a high flow rate as claimed in claim l said annular baffle means being so shaped and disposed as to direct gas from within said annular baffle means radially outwardly toward said main collecting means.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Compressors, Vaccum Pumps And Other Relevant Systems (AREA)
US840734A 1968-07-30 1969-07-10 Cryopumping installations with high flow-rates Expired - Lifetime US3579997A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR161161 1968-07-30

Publications (1)

Publication Number Publication Date
US3579997A true US3579997A (en) 1971-05-25

Family

ID=8653206

Family Applications (1)

Application Number Title Priority Date Filing Date
US840734A Expired - Lifetime US3579997A (en) 1968-07-30 1969-07-10 Cryopumping installations with high flow-rates

Country Status (9)

Country Link
US (1) US3579997A (ko)
BE (1) BE736646A (ko)
CH (1) CH512675A (ko)
DE (1) DE1937821A1 (ko)
FR (1) FR1584067A (ko)
GB (1) GB1216448A (ko)
LU (1) LU59124A1 (ko)
NL (1) NL161573C (ko)
SE (1) SE353944B (ko)

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4148196A (en) * 1977-04-25 1979-04-10 Sciex Inc. Multiple stage cryogenic pump and method of pumping
US4275566A (en) * 1980-04-01 1981-06-30 Pennwalt Corporation Cryopump apparatus
US4336690A (en) * 1979-09-28 1982-06-29 Varian Associates, Inc. Cryogenic pump with radiation shield
US4341079A (en) * 1980-04-01 1982-07-27 Cvi Incorporated Cryopump apparatus
USRE31665E (en) * 1980-04-01 1984-09-11 Cvi Incorporated Cryopump apparatus
US4475349A (en) * 1982-03-18 1984-10-09 The United States Of America As Represented By The United States Department Of Energy Continuously pumping and reactivating gas pump
US4559787A (en) * 1984-12-04 1985-12-24 The United States Of America As Represented By The United States Department Of Energy Vacuum pump apparatus
US5261244A (en) * 1992-05-21 1993-11-16 Helix Technology Corporation Cryogenic waterpump
US5426949A (en) * 1991-07-15 1995-06-27 Hitachi, Ltd. Vacuum vessel having a cooled member
US5901558A (en) * 1997-08-20 1999-05-11 Helix Technology Corporation Water pump with integral gate valve
US6155059A (en) * 1999-01-13 2000-12-05 Helix Technology Corporation High capacity cryopump
US20070039306A1 (en) * 2005-08-22 2007-02-22 Markus Mayer Cooling device for generation of a cold gas stream
JP2013155716A (ja) * 2012-01-31 2013-08-15 Sumitomo Heavy Ind Ltd コールドトラップおよびコールドトラップの制御方法

Families Citing this family (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2830943C2 (de) * 1978-07-14 1986-06-12 Leybold-Heraeus GmbH, 5000 Köln Kryopumpenanordnung
JPS60161702A (ja) * 1984-01-27 1985-08-23 Seiko Instr & Electronics Ltd 真空用冷却トラツプ
DE3512614A1 (de) * 1985-04-06 1986-10-16 Leybold-Heraeus GmbH, 5000 Köln Verfahren zur inbetriebnahme und/oder regenerierung einer kryopumpe und fuer dieses verfahren geeignete kryopumpe
WO1992008894A1 (de) * 1990-11-19 1992-05-29 Leybold Aktiengesellschaft Verfahren zur regeneration einer kryopumpe sowie zur durchführung dieses verfahrens geeignete kryopumpe
DE9111236U1 (de) * 1991-09-10 1992-07-09 Leybold AG, 6450 Hanau Kryopumpe
US5228299A (en) * 1992-04-16 1993-07-20 Helix Technology Corporation Cryopump water drain
DE4336035A1 (de) * 1993-10-22 1995-04-27 Leybold Ag Verfahren zum Betrieb einer Kryopumpe sowie Vakuumpumpensystem mit Kryopumpe und Vorpumpe
JP6871751B2 (ja) * 2017-02-07 2021-05-12 住友重機械工業株式会社 クライオポンプ

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2703673A (en) * 1950-04-08 1955-03-08 Alois Vogt Vacuum pump
US2934257A (en) * 1956-01-25 1960-04-26 Edwards High Vacuum Ltd Vapour vacuum pumps
US3081068A (en) * 1959-10-16 1963-03-12 Milleron Norman Cold trap
US3296810A (en) * 1964-08-24 1967-01-10 Nat Res Corp High conductance cold trap for vacuum systems
US3321927A (en) * 1965-02-12 1967-05-30 Jr Charles B Hood Spiral liquid cooled baffle for shielding diffusion pumps
US3364654A (en) * 1965-09-27 1968-01-23 Union Carbide Corp Ultrahigh vacuum pumping process and apparatus

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2703673A (en) * 1950-04-08 1955-03-08 Alois Vogt Vacuum pump
US2934257A (en) * 1956-01-25 1960-04-26 Edwards High Vacuum Ltd Vapour vacuum pumps
US3081068A (en) * 1959-10-16 1963-03-12 Milleron Norman Cold trap
US3296810A (en) * 1964-08-24 1967-01-10 Nat Res Corp High conductance cold trap for vacuum systems
US3321927A (en) * 1965-02-12 1967-05-30 Jr Charles B Hood Spiral liquid cooled baffle for shielding diffusion pumps
US3364654A (en) * 1965-09-27 1968-01-23 Union Carbide Corp Ultrahigh vacuum pumping process and apparatus

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4148196A (en) * 1977-04-25 1979-04-10 Sciex Inc. Multiple stage cryogenic pump and method of pumping
US4336690A (en) * 1979-09-28 1982-06-29 Varian Associates, Inc. Cryogenic pump with radiation shield
US4275566A (en) * 1980-04-01 1981-06-30 Pennwalt Corporation Cryopump apparatus
US4341079A (en) * 1980-04-01 1982-07-27 Cvi Incorporated Cryopump apparatus
USRE31665E (en) * 1980-04-01 1984-09-11 Cvi Incorporated Cryopump apparatus
US4475349A (en) * 1982-03-18 1984-10-09 The United States Of America As Represented By The United States Department Of Energy Continuously pumping and reactivating gas pump
US4559787A (en) * 1984-12-04 1985-12-24 The United States Of America As Represented By The United States Department Of Energy Vacuum pump apparatus
US5426949A (en) * 1991-07-15 1995-06-27 Hitachi, Ltd. Vacuum vessel having a cooled member
US5261244A (en) * 1992-05-21 1993-11-16 Helix Technology Corporation Cryogenic waterpump
US5901558A (en) * 1997-08-20 1999-05-11 Helix Technology Corporation Water pump with integral gate valve
US6155059A (en) * 1999-01-13 2000-12-05 Helix Technology Corporation High capacity cryopump
US20070039306A1 (en) * 2005-08-22 2007-02-22 Markus Mayer Cooling device for generation of a cold gas stream
JP2013155716A (ja) * 2012-01-31 2013-08-15 Sumitomo Heavy Ind Ltd コールドトラップおよびコールドトラップの制御方法

Also Published As

Publication number Publication date
CH512675A (fr) 1971-09-15
NL161573B (nl) 1979-09-17
GB1216448A (en) 1970-12-23
SE353944B (ko) 1973-02-19
LU59124A1 (ko) 1969-11-25
NL161573C (nl) 1980-02-15
BE736646A (ko) 1970-01-28
NL6911437A (ko) 1970-02-03
DE1937821A1 (de) 1970-02-12
FR1584067A (ko) 1969-12-12

Similar Documents

Publication Publication Date Title
US3579997A (en) Cryopumping installations with high flow-rates
US3485054A (en) Rapid pump-down vacuum chambers incorporating cryopumps
US3163998A (en) Refrigerant flow control apparatus
US5156007A (en) Cryopump with improved second stage passageway
JPH05509144A (ja) クライオポンプを再生する方法及びこの方法を実施するのに適したクライオポンプ
US3788096A (en) Cryogenic gas traps
US3122896A (en) Pump heat radiation shield
US5782096A (en) Cryopump with improved shielding
US3168819A (en) Vacuum system
JP4303886B2 (ja) 排出用フィルタを備えたクライオポンプ
JP4909260B2 (ja) クライオポンプ用バルブ・アセンブリ
EP3350501A1 (fr) Réservoir de stockage de fluide liquéfié
US4611467A (en) Method and apparatus for throttling gas flow to a cryopump
US3456456A (en) Cryogenic apparatus for producing cold
US3360949A (en) Cryopumping configuration
US3321927A (en) Spiral liquid cooled baffle for shielding diffusion pumps
US4454722A (en) Cryopump
JPH08510525A (ja) 改修型低温拡散ポンプ
US3302422A (en) Refrigeration apparatus
US3892106A (en) Method for reducing the consumption of a cryostat and a device for carrying out said method
TW201903185A (zh) 用於減少ｏｖｐｄ塗佈裝置中ｈｏ分壓之裝置及方法
JP3016093B2 (ja) 宇宙環境試験装置用の熱吸収壁
EP0214277A1 (en) METHOD AND DEVICE FOR REGENERATING CRYOPUMPS.
US4860546A (en) Vacuum system with molecular flow line
US2714484A (en) High-vacuum device