US3797264A - Low-temperature pumping device - Google Patents

Low-temperature pumping device Download PDF

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Publication number
US3797264A
US3797264A US00309701A US30970172A US3797264A US 3797264 A US3797264 A US 3797264A US 00309701 A US00309701 A US 00309701A US 30970172 A US30970172 A US 30970172A US 3797264 A US3797264 A US 3797264A
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Prior art keywords
low
temperature
chamber
pumping
screen
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Expired - Lifetime
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US00309701A
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English (en)
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J Thibault
J Boissin
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Air Liquide SA
LAir Liquide SA pour lEtude et lExploitation des Procedes Georges Claude
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Air Liquide SA
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Priority claimed from FR7142384A external-priority patent/FR2161484A5/fr
Application filed by Air Liquide SA filed Critical Air Liquide SA
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D8/00—Cold traps; Cold baffles
    • 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

  • An improved low-temperature pump and apparatus for producing very high vacua and ultra-vacua with a pumping speed which can be varied at will comprises a pumping chamber, a gas-evacuation opening formed in the said chamber, a pumping body located at a distance from the said chamber and adapted to form a main low-temperature pumping surface, comprising also means for cooling the said body to a very low temperature and, if so desired, means for forming a head screen at a moderately cold] temperature around and at a distance from the said main low-temperature pumping body, such as an internal wall of the heatinsulating chamber and a gas-permeable reflector baffle, the said pump further comprising a wall-screen continuous thermal relation with a cold element of the said low-temperature pump, forming an auxiliary lowtemperature pumping surface and disposed in a valve conduit
  • the pumping speed obtained is related to the consumption of the refrigerant fluid.
  • liquid helium is relatively expensive, it becomes necessary to look for a compromise, for apparatus of this kind, between the pumping speed and the consumption of liquid helium.
  • the pumping speed available in the vicinity of the low-temperature pump is generally from two to five times lower than that which would be available in the absence of heat screens.
  • liquid helium is generally reasonable, namely from 0.01 to 0.20 litre of liquid helium consumed approximately per hour.
  • liquid helium is generally relatively high (0.5 to 5 litres approximately of liquid helium per hour).
  • heat screens cooled by helium vapours produced inside the low-temperature pump it is strongly recommended to use heat screens cooled by helium vapours produced inside the low-temperature pump.
  • the present invention relates to low-temperature pumps in which the pumping speed can be regulated so as to adapt it to a large number of utilizations, while retaining economy of operation, which is appreciated by users.
  • the low-temperature pumping device comprises a pumping chamber, a pumping body placed at a distance from the chamber and intended to form a main low-temperature pumping surface, also comprises means for cooling the said body to a very low temperature and, if so desired, means forming a heat screen at a moderately cold temperature around and at a distance from the said main lowtemperature pumping body, such as the internal wall of the thermal isolation chamber and/or a reflecting baffle permeable to gases.
  • This device is characterized in that it comprises trap means intended to be brought to a cold and possibly a very cold temperature, and arranged in the vicinity of the said opening, together with means for the possibly partial use of the said trap means at a cold and even very cold temperature, forming a part of the low-temperature pumping surface.
  • thlese utilization means comprising a shutter which is constantly cooled and adjustable in position across the said opening, this screen being in thermal contact with a tank intended to receive a fluid at a moderately cold temperature, such as liquid nitrogen, for example.
  • the adjustable shutter is actuated by mechanical or magnetic means, with a passage fluid-tight to ultravacuum.
  • An alternativeform of the invention is characterized in that the trapping means comprise an auxiliary trapping surface interposed between the opening and a gaspermeable screen which faces the main trapping surface, and in that the utilization means comprise regulatable supply means of very cold fluid.
  • the form of the auxiliary trapping surface is chosen to be substantially annular and coaxial with the said opening, and having substantially the same transverse extension;
  • the very cold fluid adjustable supply means are comprised by a source of liquid or gaseous helium coming from the top or bottom level respectively of a tank containing helium.
  • the invention also relates to a modified lowtemperature pumping device which enables one single operation to be effected by the same actuating means (and trapping means'serving as a movable screen and means for putting the chamber to be evacuated into communication with the low-temperature pump).
  • This arrangement offers an appreciable gain in economy of helium, since it involves a device which utilizes a low-temperature pump of conventional type to which there is adapted, so to speak, a valve-screen.
  • This arrangement according to the invention is char acterized in that the means for utilizing the said wallscreen are controlled in dependence on the position of the shutter-valve, forming between the periphery of the wall-screen and the said conduit, a passage having minimum conductivity in positions of small opening of the said valve and with an increasing conductivity between a position of small opening of the valve and its maximum opening.
  • a characteristic feature of the low-temperature pump in this arrangement is that the means for utilizing the said wall-screen controlled by the position of the shutter-valve are constituted by a control rod coaxial with the said screen, the said rod] also supporting the said valve, which is also coaxial, the said wall-screen being mounted between the valve and the main lowtemperature pumping surface and being able to pass freely into the chamber opening and having a diameter slightly less than the said opening, the said chamber opening serving as a 'valve seating.
  • FIG. shows a detail in partial cross-section of the device illustrated in FIG. 1;
  • FIG. 6 is a diagrammatic view in cross-section of a modified low-temperature pumping device according to the invention.
  • FIGS. 7 to are enlarged views of the auxiliary lowtemperature pumping device with variable operation, according to the various phases of closure and opening of the valve.
  • a pumping chamber 1 comprises a wall 2 with a tubular opening 3 terminating in a flange 4 which is intended for fluid-tight coupling to a chamber in which it is desired to produce a vacuum (not shown).
  • an upper tank 5 of stainless steel fixed to the chamber and filled with liquid nitrogen
  • a second tank 6 also of stainless steel, mounted underneath the tank 5 and forming the fixing surface of the low-temperature pump, arranged in the lower portion of the chamber 1 at a distance from the wall of the chamber.
  • This tank 6 communicates with the exterior through the intermediary of a vertical tube 7 necessary for the admission and de-gassing of the helium, this tube also permitting the suspension of the tank 6 on the wall 2 by welding.
  • This tube 7 passes through a coaxial well 8 in the tank 5.
  • Another wall-screen 9a is provided between the wall 2 and the screen 9.
  • a solid circular shutter 10 which may be of nickeled copper, having a polished surface on its main faces, has a diameter in the vicinity of that of the suction flange, and is coupled through the intermediary of a rod 11 to a mechanical control accessible from the exterior of the chamber.
  • This mechanical control consists of a fluid-tight bushing device for ultra-vacuum (of the fluid-tight bushing type for passage in translation or in rotation).
  • FIG. 2 shows how the circular shutter 10 occupies upper, lower or intermediate positions by moving the rod 11 through the intermediary of the fluid-tight passage device, which may also be a toothed-rack and pinion system.
  • a metal braid 15 which is a good conductor of heat (for example nickel-plated copper) connects the liquid nitrogen tank 5 to the circular shutter 10 in such manner as to maintain this latter at a temperature in the neighbourhood of about 77 K.
  • the operation of the device according to the invention is as follows: after having filled the tank 5 with liquid nitrogen through a conduit shown at 17, liquid helium is admitted to the tank 6 through the pipe 7. After having created a primary vacuum in the chamber to be trapped, this latter is put into communication with the low-temperature pump.
  • This method is therefore advantageous when the pumping speed required is low.
  • the gases such as CO H O, etc. are condensed or solidified on the shutter 10.
  • the other gases are condensed on the tank 6.
  • a partly threaded rod 23 passes through the flange 21, the flange, the stirrup and the rod being coaxial, as shown in FIG. 5.
  • a knurled screw 24 is provided between the flange 21 and the stirrup 22 , its rotation permitting a forward travel of the thread of the rod 23 by virtue of a bearing 26.
  • the rod 23 pushes against an end-piece 32 centered on the same axis as the rod, which in turn pushes the rod 11,which serves to displace the circular shutter 10 in accordance with the invention.
  • the extremity of a bellows member 29 is sealed by a collar 28 the other extremity of this bellows being sealed to another collar 31 which rests on a sleeve 27 fixed to the flange 21 but on the face opposite to that facing the knurled screw.
  • the movement of the rod 23 and therefore of the shutter 10 is due to the rotation of the knurled screw 24 through the intermediary of the hearing 26. It is clear that the overall extent of the threads on the rod 23 is chosen to be at least equal to that which is necessary, in order to completely close the pumping opening by the shutter 10, in accordance with FIG. 2.
  • the regulation of the temperature of the trap 10a may be effected by a circulation of liquid helium coming from the receptacle 6 brought in by the pipe 7 through a coil 11 provided with a valve 12a. This coil is coupled to the bottom of the tank 6.
  • a fixed screen 8 of the herringbone baffle type is welded to the parts 9 and 9' of the screen surrounding the tank 6.
  • This screen 8 permits the passage of the gases to be pumped at low temperatures while protecting the tank 6 from unfavorable heating by direct radiation through the opening 3. It can be seen that by opening the valve 12a, the liquid helium will circulate by gravity in the coil 11 and will bring the trap a to a temperature in the vicinity of 42 K.
  • valve 12a During normal operation, that is to say at a low pumping speed, the valve 12a is closed.
  • valve 12a During operation at high pumping speed, the valve 12a is open.
  • FIG. 4 shows a device similar to that described previously, in which gaseous helium is employed to cool the trap 10a.
  • the circuit further comprises a valve 12 mounted on the pipe 7 and an electric resistance R placed in the bath of helium monitors the vaporization.
  • valve 12 being closed, the valve 12a is then opened and a high pumping speed is then obtained.
  • valve 12a During normal operation, that is to say at a low pumping speed, the valve 12a is closed and the valve 12 is opened.
  • the isolating valve between the low-temperature pump and the space to be pumped out may be closed during this operation (with a duration from a few seconds to a few minutes).
  • a pumping chamber 1 comprises a wall 2 with a tubular chamber opening 3 terminating in a flange 4 intended to receive a valve 100 for fluid-tight coupling to a chamber in which the vacuum is to be created (not shown).
  • This tank 6 communicates with the exterior by means of a vertical tube 7 necessary for the admission and degassing of the helium, this tube also providing the suspension of the tank 6 by welding to the wall 2.
  • This tube 7 passes through a coaxial well 8 into the tank 5.
  • a screeen of nickel-plated copper shown at 9 and 9', is soldered to the wall of the tank 5 and substantially surrounds the tank 6 while forming a clearance be tween the low-temperature pumping zone of the tank 6 and the chamber opening 3.
  • Another screen 9a is placed between the wall 2 and the screen 9.
  • the valve 100 comprises, as shown in FIGS. 7 to 10, a flange opening 101 adaptedby screws 650 to the flange 4.
  • the opening 101 has a shoulder 302, and the valve 100 is also provided with a tubular opening 304 with a flange 102 capable of receiving the chamber to be pumped.
  • This opening 304 is mounted perpendicular to the opening 101 which offers a degree of angular orientation freedom of the chamber with respect to the vertical tube 7, of 180.
  • the valve 100 comprises a closure clapper 614 mounted on a central control rod 612 of tubular shape.
  • This clapper 614 has a toric joint 615 and is applied against a joint plane 16 which is suitably machined on the internal face of the flange 101.
  • the clapper 614 is thus capable of closing the chamber opening 3 by means of the flange 101 and is thus adjustable in position.
  • the rod 612 communicates with the exterior of the valve 100, as shown in FIG. 6, by one of its extremities 612', by any known means, for example a fluid-tight bellows passage (not shown).
  • This control may be mechanical and/or magnetic.
  • the other extremity 612" carries the clapper 614 and also a wall-screeen 100' mounted in front of the said clapper, which means that this wall 100 is located between the clapper and the trapping surface 6.
  • the wall-screen 100 is mounted coaxially with the rod 612, and has a diameter smaller than the chamber opening 3, thus being able to pass freely into the said opening 3, which serves in a way as a seating for the clapper 614, through the intermediary of the flange 101.
  • the rod 612 comprises at its extremity facing the flange 4, a ring 18 welded on the rod and provided with a collar 18a fitted with a toric joint 19 against which is supported the clapper 614.
  • a washer 20 and a circlip 21 hold the clapper 614 against the joint 19.
  • the ring 18 is provided axially and facing the opening 3 with a threaded hole coaxial with the rod 612 capable of receiving a sleeve 22 which is also threaded and which has one cylindrical extremity 22a which has a smaller diameter than the rod 612 and which can thus be passed on the said rod after screwing the sleeve 22 into the ring 18 by means of the threaded hole 30.
  • a joint 31 ensures fluid-tightness between the sleeve 22 and the ring 18.
  • Two blind holes coaxial with the rod 612 are formed on the same side in the sleeve 22, one of smaller diameter but of greater depth 110, the other 111 with a groove lllb of greater diameter but limited in depth.
  • a partly threaded rod 23 slides freely in the holes 110 'and 111.
  • a spring 24 is placed on the rod 23 and a washer 24b, welded to the rod 23 and having a diameter slightly less than the hole 11 1 permits the compression of the spring 24 inside the hole 111 which comes into abutment against the groove lllb.
  • the threaded portion of the rod 23, external to the holes 110 and 111, carries the wall-screen 10 formed by two discs coaxial with the rod 612, the first 10a having a number of circular perforations a, uniformly distributed over the disc, the other 10b being of smaller diameter and interposed between the first and the clapper 614, and separated from the spacer 27.
  • the discs 10a and 10b are rigidly fixed on the rod 23 by means of two washers 25 and 26 and a blind nut 28 which screws on the threaded extremity of the rod 23.
  • On the flange'18 a threaded plug 29 is mounted on the side of the wall-screen 100'. This plug is bored to a diameter slightly greater than that of the rod 23, so that the rod 23 can circulate freely in. the holes 110, 111, within the limits of movement of the washer 24b between the washer 24 and the plug 29.
  • the rod 612 serves as a utilization means for the wall-screen 100 and is controlled in dependence on the position of the closure clapper 6
  • This device may be constituted by a ring 200 in which is mounted a ring 201 in two parts.'Six screws equally distributed in the ring 201 are screwed into six L-shaped brackets and thus ensure good thermal contact with the ring 200.
  • this ring 200 is welded a shell 203 of smaller diameter than that of the flanged opening 3, and the other extremity of which is welded to a second shell 205 facing the clapper 614, having a diameter slightly greater than that of the shell 203, but less than that of the opening 3.
  • the shell 203 is chosen with a diameter close to that of the disc, the edges 10021 of which are deliberately curved back so as to be applied against the said shell.
  • the shells or collars 203 and 205 are brought up to the temperature of the liquid nitrogen by means of the contacts 90 and 90 and form the cold element of the low-temperature pump. Furthermore, the arrangement of the collar 205 is chosen in such manner that it serves as an optical screen for the helium tank 6.
  • This valve 100 has a conduit 299 which communicates on the one hand through the opening 304 with the chamber to be evacuated, and on the other hand through the opening 3 with the low-temperature pumping surface.
  • the periphery of the wall-screen 100' will describe a displacement contour-envelope such as shown in broken lines in FIGS. 9 and 10, and thus the edges 100b of the disc 10a describe a cylinder of revolution having an axis identical with that of the rod 612, and between the wall-screen 100' and the conduit 299, the rod 612 forms a clearance, passage which increases the conductivity and permits access of the gas to be trapped on the main low-temperature pumping surface 6.
  • the wall-screen 100 being provided with circular perforations 100a, the gases can pass through this wallscreen so as to reach the surface 6.
  • the wall-screen 100 can remain forced against the collar 203 while the clapper 614 moves away from its joint plane 16.
  • the clearance passage is then shown in FIG. 8 by the references 303, 303', 305 and 305 as shown by the arrows.
  • the clearance passage is zero, that is to say the conductivity is a minimum when the valve 614 is totally closed and it may also be as low as possible (see FIG. 8) when the said clapper is lifted away from its joint plane 16, the gases then following the path 303, 303' and 305, 305' while being capable of being partly trapped on the wall-screen 100 (H O, CO for example).
  • This clearance passage remains as small as possible, as long as the spring 24 is not de-compressed. Then, by continuing to operate the rod 612, the wall-screen 100' is separated from the collar 203 and the clearance passage becomes increasingly large (see the arrow and the reference 301, 301, 303, 303', 305 and 305 shown in FIGS. 9 and 10), and the gases pass directly on to the surface; the conductivity is then increasing. As and when the clapper 614 is moved away from the seating plane 16, the clearance passage increases and the conductivity becomes increasingly large.
  • liquid helium is admitted to the tank 6 by the pipe 7. After having produced a primary vacuum in the chamber to be evacuated, this latter can be put into communication with the lowtemperature pump.
  • the clapper 614 is then supported at the level of the joint 615 on the seating plane 16, and the wall-screen closes the collar 203 by means of the disc 10a.
  • the clapper 614 is opened and moves away from its seating plane 16.
  • the assembly of the plug 29, flange 22, ring 18 and clapper 614 being rigidly fixed on the operating rod 22 moves, but the wall-screen 100 remains closed, since the rod 23 slides freely in the holes and 111, and the spring 24b is still sufficiently compressed to hold the wall-screen 100 against the collar 203.
  • certain gases such as CO and H 0 become condensed or solidified on the wall-screen 100 and also on the collars 203 and 205.
  • the pumping speed concerned is low. The consumption of liquid helium is lower and the lowtemperature pump can work for longer periods.
  • control rod 612 In order to do this, the control rod 612 must be pulled in such manner that the spring 24 is compressed by the washer 24b when the plug 29 comes into abutment against it. It is clear that any intermediate position of the screen may be contemplated, which permits a substantial modification of the pumping speed, since the overall displacement of the rod 612 may be equal to the length of the valve 100.
  • the external control device which may, as has previously been stated, be of the mechanical and/or magnetic type, so that the clapper 614 becomes applied against the seating plane 16 and that the screen 100' comes into contact with the collar 203 at the level of the disc 100.
  • the low-temperature pumps thus described may advantageously be provided with a device for the introduction of argon, as described in US. Pat. application Ser. No. 198,178, filed Nov. 12, 1971 now US. Pat. No. 3,769,806.
  • the chamber 1 may be adapted for example to an evaporation chamber for the production of thin layers or to a furnace under high vacuum or ultravacuum.
  • a low-temperature pumping device of the kind comprising a pumping chamber, a gas-evacuation opening in said chamber, a pumping body located at a distance from said chamber and adapted to form a main low-temperature pumping surface, comprising also means for cooling said body to a very low temperature and, if so required, means for forming a heat screen at a moderately cold temperature around and at a distance from said main low-temperature pumping body, such as an internal wall of the heat-insulating chamber and a gas-permeable reflector baffle; said device further comprising trapping means adapted to be brought to a cold and possibly very cold temperature and disposed in the vicinity of said chamber opening, together with means for putting said trapping means at least partially into operation at a cold and possibly very cold temperature, said trapping means forming part of said low-temperature pumping surface.
  • a low-temperature pumping device as claimed in claim 1, in which said means for putting said trapping means into operation comprise a continuously cooled shutter adjustable in position across the opening in said chamber.
  • At least one of these pipes being fitted with a regulating valve.
  • said adjustable supply means of very cold fluid comprise an admission pipe connected to an upper point of a helium tank and a vapour-evacuation pipe, together with means for putting the helium vapour in said tank under a variable pressure.
  • a low-temperature pump of the kind comprising a pumping chamber, a gas-evacuation opening formed in said chamber, a pumping body located at a distance from said chamber and adapted to form a main lowtemperature pumping surface, comprising also means for cooling said body to a very low temperature and, if so required, means for forming a heat screen at a moderately cold temperature around and at a distance from said main low-temperature pumping body, such as an internal wall of the heat-insulating chamber and a gaspermeable reflector baffle, said pump further comprising a wall-screen continuously in thermal relation with a cold element of the low-temperature pump, forming an auxiliary low-temperature pumping surface and disposed in a valve conduit adapted to be connected to a chamber to be evacuated, said valve being equipped with a clapper adjustable in position and adapted to close the opening in said pumping chamber, and also with means for putting said wall-screen into operation, in which said means for putting said wall-screen into operation are controlled in dependence on

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Compressors, Vaccum Pumps And Other Relevant Systems (AREA)
US00309701A 1971-11-26 1972-11-27 Low-temperature pumping device Expired - Lifetime US3797264A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR7142384A FR2161484A5 (en) 1971-11-26 1971-11-26 Cold-pump assembly - for prodn of ultra-vacuum using liquid helium
FR7224603A FR2192620A6 (it) 1971-11-26 1972-07-07

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US3797264A true US3797264A (en) 1974-03-19

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US00309701A Expired - Lifetime US3797264A (en) 1971-11-26 1972-11-27 Low-temperature pumping device

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US (1) US3797264A (it)
JP (1) JPS567066B2 (it)
BE (1) BE791888A (it)
CA (1) CA968170A (it)
CH (1) CH569194A5 (it)
DE (1) DE2257652A1 (it)
FR (1) FR2192620A6 (it)
GB (1) GB1415332A (it)
IL (1) IL40902A (it)
IT (1) IT970940B (it)
LU (1) LU66552A1 (it)
NL (1) NL7216050A (it)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4072025A (en) * 1975-08-22 1978-02-07 L'air Liquide, Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges Claude Regeneration-type cryopump
US4485631A (en) * 1982-09-17 1984-12-04 Balzers Aktiengesellschaft Method and apparatus for rapidly regenerating a self-contained cryopump
US4722191A (en) * 1986-09-17 1988-02-02 Pennwalt Corporation High vacuum pumping system
EP0370702A1 (en) * 1988-11-23 1990-05-30 AT&T Corp. Apparatus comprising a high vacuum chamber
DE4324311A1 (de) * 1992-07-21 1994-01-27 Marcel Kohler Kryopumpe
US20090257888A1 (en) * 2002-05-07 2009-10-15 Flometrics, Inc. Multiple chamber pump and method
US9117563B2 (en) * 2014-01-13 2015-08-25 Cold Quanta, Inc. Ultra-cold-matter system with thermally-isolated nested source cell

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0102787B1 (en) * 1982-08-27 1986-07-16 Comptech, Incorporated Cryogenic pump having maximum aperture throttled port
CN114893389B (zh) * 2022-06-10 2023-06-30 中国科学院上海高等研究院 一种氦减压降温泵组室温性能的测试系统及方法

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3371499A (en) * 1966-11-02 1968-03-05 Union Carbide Corp Cryosorption vacuum pumping system
US3579998A (en) * 1968-08-01 1971-05-25 Air Liquide Cryogenic pumping device for the creation of very high vacua
US3668881A (en) * 1969-12-01 1972-06-13 Air Liquide Adsorptive cryopumping method and apparatus

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3371499A (en) * 1966-11-02 1968-03-05 Union Carbide Corp Cryosorption vacuum pumping system
US3579998A (en) * 1968-08-01 1971-05-25 Air Liquide Cryogenic pumping device for the creation of very high vacua
US3668881A (en) * 1969-12-01 1972-06-13 Air Liquide Adsorptive cryopumping method and apparatus

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4072025A (en) * 1975-08-22 1978-02-07 L'air Liquide, Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges Claude Regeneration-type cryopump
US4485631A (en) * 1982-09-17 1984-12-04 Balzers Aktiengesellschaft Method and apparatus for rapidly regenerating a self-contained cryopump
US4722191A (en) * 1986-09-17 1988-02-02 Pennwalt Corporation High vacuum pumping system
EP0370702A1 (en) * 1988-11-23 1990-05-30 AT&T Corp. Apparatus comprising a high vacuum chamber
DE4324311A1 (de) * 1992-07-21 1994-01-27 Marcel Kohler Kryopumpe
US5343709A (en) * 1992-07-21 1994-09-06 Marcel Kohler Cryopump
US20090257888A1 (en) * 2002-05-07 2009-10-15 Flometrics, Inc. Multiple chamber pump and method
US7611333B1 (en) * 2002-05-07 2009-11-03 Harrington Steven M Multiple chamber pump and method
US9117563B2 (en) * 2014-01-13 2015-08-25 Cold Quanta, Inc. Ultra-cold-matter system with thermally-isolated nested source cell

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DE2257652A1 (de) 1973-05-30
CA968170A (en) 1975-05-27
CH569194A5 (it) 1975-11-14
GB1415332A (en) 1975-11-26
FR2192620A6 (it) 1974-02-08
IT970940B (it) 1974-04-20
BE791888A (fr) 1973-05-24
NL7216050A (it) 1973-05-29
JPS4860313A (it) 1973-08-24
IL40902A0 (en) 1973-01-30
LU66552A1 (it) 1973-02-01
JPS567066B2 (it) 1981-02-16
IL40902A (en) 1976-01-30

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