US3326451A - Process for the production of an ultra-high vacuum - Google Patents

Process for the production of an ultra-high vacuum Download PDF

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Publication number
US3326451A
US3326451A US512670A US51267065A US3326451A US 3326451 A US3326451 A US 3326451A US 512670 A US512670 A US 512670A US 51267065 A US51267065 A US 51267065A US 3326451 A US3326451 A US 3326451A
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United States
Prior art keywords
working fluid
vessel
diffusion pump
pump
high vacuum
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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
US512670A
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English (en)
Inventor
Gaydou Francois
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.)
Bendix Balzers Vacuum Inc
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Bendix Balzers Vacuum Inc
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Publication date
Application filed by Bendix Balzers Vacuum Inc filed Critical Bendix Balzers Vacuum Inc
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04F—PUMPING OF FLUID BY DIRECT CONTACT OF ANOTHER FLUID OR BY USING INERTIA OF FLUID TO BE PUMPED; SIPHONS
    • F04F9/00—Diffusion pumps
    • F04F9/04—Diffusion pumps in combination with fore pumps, e.g. use of isolating valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04F—PUMPING OF FLUID BY DIRECT CONTACT OF ANOTHER FLUID OR BY USING INERTIA OF FLUID TO BE PUMPED; SIPHONS
    • F04F9/00—Diffusion pumps

Definitions

  • the present invention is concerned with a process for the production of an ultra-high vacuum in a vessel by means of a diffusion pump and a forepump connected to it where the diffusion pump is in communication with a storage container arranged outside of its working fluid boiler.
  • a diffusion pump with a working-fluid-storage-container situated outside of its boilerchamber having a charging conduit through which the Working fluid is fed by a drainage gutter arranged at the lower end of the condensation wall of the diffusion pump and a connecting conduit between the storage container and the boiler for returning the working fluid into the diffusion pump and an arrangement for the control of the flow of the working fluid.
  • the object of the above known device is to quickly pressurize the evacuated system and afterwards to quickly evacuate it again, since it is important to hold the working fluid at a temperature close to its boiling temperature during the time the vessel is open in order to avoid the unnecessary lost time arising through cooling and subsequent heating again of the working fluid.
  • Another known vapor vacuum pump with a boiler has one or more jets for the delivery of the vapor produced in the boiler, a main vapor pipe which connects the boiler with the pump jets and supplies them with vapor, a valve for shutting off the boiler from the main pipe and for in terrupting the vapor supply to the pump jets, and a condenser which, during the shutting off of the boiler from the main pipe, condenses away the vapor produced at such a rate that the resulting temperature drop of the working fluid as well as the pressure in the boiler may be held at predetermined values.
  • This known device also only serves to avoid the difliculty which would occur if the working fluid were exposed to air at atmospheric pressure at the operating temperature.
  • the present invention is concerned with a process for the production of an ultra-high vacuum. It is usual to bake out a vessel which is to be evacuated to ultra-high vacuum, at a temperature of 450 C., in order to remove the gases absorbed on the inner walls. For this purpose it is customary to surround the part of the equipment to be heated with heat radiation.
  • the process for the production of an ultra-high vacuum in a vessel according to the invention by means of a diffusion pump and the forepump connected to it in which the diffusion pump is arranged with a storage container outside its working fluid boiler and being in connection with it is characterized in that after the evacuation of the connected vessel to a predetermined initial high vacuum and before the evacuation to ultra-high vacuum, the working fluid 3,326, 15 1 Patented June 20, 1967 will be distilled into the storage container from the boiler of the diffusion pump under the simultaneous pumping by the after connected forepurnp, later returned to the connected boiler of the diffusion pump and the further evacuation of the vessel to ultra-high vacuum is then carried out.
  • Numeral 1 designates a vessel to be evacuated to ultrahigh vacuum to which an apparatus 2 for the prevention of oil backstrearning (a s0-called baffle) and a diffusion pump 3 are connected.
  • the discharge pipe 4 of this diffusion pump leads to a second diffusion pump 5 which is connected in series with the first diffusion pump 3.
  • the discharge pipe of the second diffusion pump in turn is in communication with the rotating forepump 7 through the pipe 6.
  • the connecting pipe 4 between the two diffusion pumps is constructed in a special manner for the carrying out of the invention. As the drawing shows, it is inclined upwards and shows a laterally attached condensation pipe stub 11 for the working fluid on whose bottom an electrical heater 1?. is fitted.
  • the portion 13 of the connecting pipe 4 between the stub 11 and the pump 5 is provided with a cooling wall, for eXample, in the form of a surrounding cooling coil 14.
  • the ultra-high vacuum pump directly connected to the vessel is heated as a whole through putting in an oven, then the working fluid vapor is led off through the pipe 4 and is condensed on the wall of its upper part 13.
  • the actual baking out at a temperature above the boiling point of the working fluid can begin.
  • the gas load of the gases to be released from the inner walls of the pump and the degree of evacuation to be subsequently attained in the vessel, the baking out will require between a half hour to several hours.
  • the working fluid in the stub 11 can be distilled back into the first diffusion pump 3 by putting the heater 12 into operation.
  • the Working fluid vapor flows out of 11, part going directly into the first diffusion pump 3 and will there be condensed on its again cooled inner walls, and part going to the cooled portion 13 of the connecting pipe 4 where it is likewise condensed and flows back into the stub 11 and is again vaporized until finally all of the working fluid is brought back again into the first diffusion pump 3 with the exception of the easily escaping components (light ends) which will be removed during the process by the running forepump 5.
  • the evacuation of the vessel 1 to ultra-high vacuum can be carried outwith the first diflusion pump 3.
  • a valve is provided between the vessel 1 and the diffusion pump 3 to be baked out, so that both spaces can be separated from each other, it is recommended to first outgas the vessel alone in the usual manner by baking out and pumping off the liberated gases through the running diffusion pump and immediately following this also carry out the baking out of the diffusion pump as was described above, during which the vessel and the diffusion pump being baked out are separated from one another by the valve. In this way, one can prevent the entrance of large amounts of the working fluid into the vessel and there to possibly cause detrimental reactions, for example, with the filament of the ionization gauge.
  • a special pipe can be provided for its return in liquid form.
  • the invention yields the advantages of a better ultimate vacuum, shorter evacuation time and simultaneously, a basic operating purification of the working fluid of the pump from all easily escaping components (light ends) which arise in the course of the operation (or on occasion existing from the beginning) and could very well impair the excellence of the vacuum.
  • an ultra-high vacuum pumping system which without the processing according to the invention, could be evacuated, after previously baking out the vessel in the previous usual manner, to a vacuum of torr in the vessel within about 72 hours, a pumping time reduction of 50 hours, that is to say /3, was achieved by the use of this invention.
  • the distillation of the working fluid over into the stub 11, the baking out of the diffusion pump and the return distillation required approximately one hour. It is to be observed that this time is not in addition to the normal pump time that must be used since the processing steps referred to can be carried out during the same time in which the vessel is being outgassed by baking out.
  • a process for producing an ultra-high vacuum in a vessel employing a diflusion pump, a forepump, and working fluid storage container external to and communicating with the diffusion pump comprising the steps of:
  • step of removing the working fluid to the storage container comprises:
  • step of returning the working fluid from the storage container to the diflusion pump comprises:
  • a process for producing an ultra-high vacuum in a vessel employing a diffusion pump, a forepump means, and a working fluid storage container external to and communicating with the diffusion pump comprising the steps of:
  • An apparatus for producing an ultra-high vacuum in a vessel comprising:
  • a first diffusion pump having a connection to said vessel
  • a trap means comprising a stub pipe member, and a heating element disposed adjacent the bottom of said stub pipe member; said trap means adapted to catch the condensate produced in said first pipe means.
  • said first pipe means interconnects the discharge of the first diffusion pump and the intake of the second diffusion pump; and said first pipe means is obliquetly inclined.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Compressors, Vaccum Pumps And Other Relevant Systems (AREA)
  • Vaporization, Distillation, Condensation, Sublimation, And Cold Traps (AREA)
US512670A 1964-12-18 1965-12-09 Process for the production of an ultra-high vacuum Expired - Lifetime US3326451A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CH1639764A CH414928A (de) 1964-12-18 1964-12-18 Verfahren zur Erzeugung eines Ultrahochvakuums

Publications (1)

Publication Number Publication Date
US3326451A true US3326451A (en) 1967-06-20

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Family Applications (1)

Application Number Title Priority Date Filing Date
US512670A Expired - Lifetime US3326451A (en) 1964-12-18 1965-12-09 Process for the production of an ultra-high vacuum

Country Status (3)

Country Link
US (1) US3326451A (de)
CH (1) CH414928A (de)
NL (1) NL6502684A (de)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3443743A (en) * 1966-11-15 1969-05-13 Clover Soc Vacuum pumps

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2501276A (en) * 1945-06-14 1950-03-21 Eastman Kodak Co Vacuum production apparatus
US2636655A (en) * 1948-12-15 1953-04-28 Photoswitch Inc High vacuum system with recirculating conduit
US2696344A (en) * 1951-08-21 1954-12-07 Edwards & Co London Ltd W Vapor vacuum pump
US2797043A (en) * 1953-06-16 1957-06-25 Cons Electrodynamics Corp Vacuum pump
US2806644A (en) * 1953-08-13 1957-09-17 Cons Electrodynamics Corp Vacuum system apparatus
US2902206A (en) * 1955-07-04 1959-09-01 Edwards High Vacuum Ltd Vapour vacuum pumps
US2935243A (en) * 1955-12-09 1960-05-03 N G N Electrical Ltd Vacuum pumping apparatus
US3066849A (en) * 1960-08-18 1962-12-04 Exemplar Inc High vacuum pump systems
US3144199A (en) * 1961-07-20 1964-08-11 Isen Ind Inc Method of evacuating treating chambers

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2501276A (en) * 1945-06-14 1950-03-21 Eastman Kodak Co Vacuum production apparatus
US2636655A (en) * 1948-12-15 1953-04-28 Photoswitch Inc High vacuum system with recirculating conduit
US2696344A (en) * 1951-08-21 1954-12-07 Edwards & Co London Ltd W Vapor vacuum pump
US2797043A (en) * 1953-06-16 1957-06-25 Cons Electrodynamics Corp Vacuum pump
US2806644A (en) * 1953-08-13 1957-09-17 Cons Electrodynamics Corp Vacuum system apparatus
US2902206A (en) * 1955-07-04 1959-09-01 Edwards High Vacuum Ltd Vapour vacuum pumps
US2935243A (en) * 1955-12-09 1960-05-03 N G N Electrical Ltd Vacuum pumping apparatus
US3066849A (en) * 1960-08-18 1962-12-04 Exemplar Inc High vacuum pump systems
US3144199A (en) * 1961-07-20 1964-08-11 Isen Ind Inc Method of evacuating treating chambers

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3443743A (en) * 1966-11-15 1969-05-13 Clover Soc Vacuum pumps

Also Published As

Publication number Publication date
CH414928A (de) 1966-06-15
NL6502684A (de) 1966-06-20

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