US3207423A - Vacuum pump - Google Patents

Vacuum pump Download PDF

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Publication number
US3207423A
US3207423A US211991A US21199162A US3207423A US 3207423 A US3207423 A US 3207423A US 211991 A US211991 A US 211991A US 21199162 A US21199162 A US 21199162A US 3207423 A US3207423 A US 3207423A
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US
United States
Prior art keywords
pump
wall
sphere
vacuum pump
present
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
US211991A
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English (en)
Inventor
Huber Harry
Graulcau Didier
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.)
Thales SA
Original Assignee
CSF Compagnie Generale de Telegraphie sans Fil 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 CSF Compagnie Generale de Telegraphie sans Fil SA filed Critical CSF Compagnie Generale de Telegraphie sans Fil SA
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Publication of US3207423A publication Critical patent/US3207423A/en
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Expired - Lifetime legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J41/00—Discharge tubes for measuring pressure of introduced gas or for detecting presence of gas; Discharge tubes for evacuation by diffusion of ions
    • H01J41/12—Discharge tubes for evacuating by diffusion of ions, e.g. ion pumps, getter ion pumps
    • H01J41/14—Discharge tubes for evacuating by diffusion of ions, e.g. ion pumps, getter ion pumps with ionisation by means of thermionic cathodes
    • H01J41/16—Discharge tubes for evacuating by diffusion of ions, e.g. ion pumps, getter ion pumps with ionisation by means of thermionic cathodes using gettering substances
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J41/00—Discharge tubes for measuring pressure of introduced gas or for detecting presence of gas; Discharge tubes for evacuation by diffusion of ions
    • H01J41/12—Discharge tubes for evacuating by diffusion of ions, e.g. ion pumps, getter ion pumps
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J7/00—Details not provided for in the preceding groups and common to two or more basic types of discharge tubes or lamps
    • H01J7/14—Means for obtaining or maintaining the desired pressure within the vessel
    • H01J7/18—Means for absorbing or adsorbing gas, e.g. by gettering

Definitions

  • the present invention relates to vacuum pumps operable wit-l1 thermal evaporation of a metal having gettering properties, that is, to devices connected with the enclosures to be evacuated and intended to improve the vacuum by the adsorption effect of the gases on a metal which is evaporated in a continuous manner and the condensation of which is caused in a thin layer along a wall.
  • Titanium is generally chosen as suitable metal for this application by reason of its high chemical activity, particularly insofar as the most common gases are con cerne-d, of the relatively slight vapor pressure of the metallic titanium and of its compounds, and of the stability of most of the titanium compounds in the solid form at ordinary temperature.
  • the evaporation of the titanium may be assured by any known heating means, for example, by the Joule effect or by electron bombardment; the evaporation of the titanium may be controlled by means which depend on the mode of the heating employed, for example, by varying the heating current in case of heating by Joule effect, or by controlling the intensity of the electron flow emitted by a cathode with a view to bombard the titanium reserve.
  • the present invention aims at a pump which has a length of life superior to that of the pumps of this type known in the prior art with equality in the pumping speed, or which offers a higher pumping speed with equality in length of life.
  • the invention is based on the observation that the end of life of the titanium pump is principally determined .by the separation of the layer of active material condensed on the wall, at the end of a time less than the time of exhaustion of the active material. Consequently, the present invention provides means to increase this time of separation or detachment of the condensed active material in such a manner that it becomes at least equal to the duration of the life of the pump determined by exhaustion of the active material.
  • a first means in conformity with the present invention consists in giving to the elements of the pump a geometry such that the deposit of active material is as homogeneous as possible over the entire surface of the condensation wall. It is obvious in effect that, all other things remaining the same, the separation of the active material is favored by the non-homogeneity of the deposit and will commence at the place where the same i the thickest.
  • This geometry according to the present invention is spherical; according to the present invention, the conuse densation wall of the titanium pump will, therefore, have a form materializing at least in part the surface of a sphere of which other portions of the surface are realized, to the extent of need thereof, by auxiliary shields or screens.
  • a second means to increase the duration of separation consists in increasing the roughness or unevenness of the internal walls of the sphere, for example, by providing them with grooves.
  • Still a further object of the present invention resides in the provision of a vacuum pump which correlates the supply of gettering material to be coextensive with the life expectancy of the other parts without the need of movable parts within the pump.
  • a further significant object of the present invention resides in the provision of a vacuum pump operable by thermally evaporating a gettering metal in which the period of time is effectively increased before the layer of the active material condense-d along the walls of the pump begins to separate therefrom.
  • FIGURE 1 is a longitudinal cross sectional view through a first embodiment of a vacuum pump in accordance with the present invention
  • FIGURE 2 is a longitudinal cross sectional view through a second embodiment of a vacuum pump in accordance with the present invention.
  • FIGURE 3 is a longitudinal cross sectional view through a third embodiment of a vacum pump in accordance with the present invention.
  • FIGURE 4 is a partial view of a portion of the internal surface of the Walls of any one of the pumps of FIG- URES l to 3.
  • the pump illustrated therein is in communication with the evacuated enclosure or vessel (not shown) through an orifice 1.
  • the pump is thereby fixed to the walls of this enclosure with the aid of a metallic joint 2.
  • the pump is contained within a housing constituted by a vat-like receptacle, for example, made of stainless steel, and forming the condensation walls cooled by a liquid circulating within the coil 4.
  • a vat-like receptacle for example, made of stainless steel
  • at least one portion of the wall of the receptacle 3 has, as indicated at 5, a spherical configuration flowing through the tubulure 8.
  • the shield 7 is dimensioned and disposed in such a manner as to leave a pas-.
  • the reserve of the active material as-'. sumes the. shape of a titanium ball 9; realized, for example, by fusion within vacuum in the course of a preliminary operation, this ball 9 being supported by a metallic rod 10, for example, made of molybdenum and leaving across an insulating passage 11 through a me-. tallic joint 12 incorporated within the. walls of the receptacle 3.
  • the rod 10 is carried at an anode potential by a suitable external source (not shown).
  • a suitable external source not shown
  • the receptacle 3 is carried at a still more negative potential than the cathode potential by any suitable means.
  • an auxiliary filament 16 may be provided, supported by the same rods 14 and intended to emit a current owing to which the ionization will be complete.
  • the modified embodiment of the pump of FIGURE 2 differs from the embodiment of FIGURE 1 by the fact that the source of the active material is no longer' placed at the center of the sphere 6 but instead at a point of the surface thereof, particularly at a lower .point,the orifice 1 being oriented toward the top as inthe embodiment of FIGURE 1.
  • the titanium is no longer a molten ball but fills a crucible 17 placed at the level of the spherical walls within an appendage 18 connected to the receptacle 3.
  • the bombardment filament 13 is placed in the vicinity of the walls of the crucible 17, :and a thermal shield 19 is disposed between the filament 13 and the outside.
  • the auxiliary ionization filament 16 has been placed toward the center of the sphere but could also be suppressed if the necessity thereof does not become noticeable.
  • FIGURE 3 differs from the embodiment of FIGURE '-1 by 'the fact that the orifice 1 is'oriented toward the bottom, the crucible 17 being disposed as in the preceding embodiment of FIGURE 2 at the bottom of the sphere 6.
  • the rod supports a foot portion having several branches 20 from which is suspended the crucible 17.
  • the joint 12 with the passages 11 and ispl-aced toward the top of the spherical wall 5.
  • the internal spherical surfaces may be provided with grooves or ridges to increase the adherence 4 of the deposit of the active material, these grooves being indicated in FIGURE 4 and designated therein by reference numeral 21 which shows a view of a portion of the internal surface 5 that may belong to any one of the pumps of FIGURES 1 to 3.. 1
  • the coil 4 may be brazed 'to the receptacle 3 and cooled by water or eventually by freon from a refrigerating installation.
  • the passages 11 and 15 may be realized by a seal of pure alumina and titanium.
  • the joints 2 and 12 may be of the type having a gold, copper or aluminum ring, as is known in the art. 1 g
  • any control means known to a person skilled in the art may be associated with the heating system for the active metal in order to increase the temper ature to the extent that the evaporating surface decreases by use in such a manner as to conserve a constant evapora tion speed of the metal and, therefore, a constant pump ing speed.
  • the heating system by bombardment may itself be replaced by any other equivalent system without departing from the spirit of the present invention.
  • a high vacuum pump having an orifice for communication with the enclosure to be evacuated and including means for thermally evaporating a metal having gettering properties and means for condensing said metal on a wall, said wall having a shape materializing at least in part a sphericalsurface, and at least one additional shield having a part spherical surface substantially completing the sphere defined by said wall surface, said shield being separated from said wall by an interval forming passage between the inside of said sphere and said orifice.

Landscapes

  • Compressors, Vaccum Pumps And Other Relevant Systems (AREA)
  • Electron Tubes For Measurement (AREA)
US211991A 1961-09-07 1962-07-24 Vacuum pump Expired - Lifetime US3207423A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR872546A FR1306718A (fr) 1961-09-07 1961-09-07 Perfectionnements aux pompes à vide à évaporation thermique de titane

Publications (1)

Publication Number Publication Date
US3207423A true US3207423A (en) 1965-09-21

Family

ID=8762400

Family Applications (1)

Application Number Title Priority Date Filing Date
US211991A Expired - Lifetime US3207423A (en) 1961-09-07 1962-07-24 Vacuum pump

Country Status (4)

Country Link
US (1) US3207423A (enrdf_load_stackoverflow)
FR (1) FR1306718A (enrdf_load_stackoverflow)
GB (1) GB951866A (enrdf_load_stackoverflow)
NL (1) NL282934A (enrdf_load_stackoverflow)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3495769A (en) * 1968-03-12 1970-02-17 Robert L Hirsch Space charge controlled vacuum pump
US3924967A (en) * 1974-03-22 1975-12-09 Varian Associates Sublimation vacuum pump having a removable gas permeable condenser
WO2001043162A3 (de) * 1999-12-08 2002-07-25 Max Planck Gesellschaft Ionengetterpumpe

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3249291A (en) * 1964-04-01 1966-05-03 Varian Associates Vacuum pump method and apparatus

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2920002A (en) * 1952-06-25 1960-01-05 Auwarter Max Process for the manufacture of thin films
DE1095455B (de) * 1958-06-03 1960-12-22 Philips Nv Ringfoermiger Fangstoffbehaelter
US3056740A (en) * 1956-10-12 1962-10-02 Edwards High Vacuum Ltd Vapourisation of metals

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2920002A (en) * 1952-06-25 1960-01-05 Auwarter Max Process for the manufacture of thin films
US3056740A (en) * 1956-10-12 1962-10-02 Edwards High Vacuum Ltd Vapourisation of metals
DE1095455B (de) * 1958-06-03 1960-12-22 Philips Nv Ringfoermiger Fangstoffbehaelter

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3495769A (en) * 1968-03-12 1970-02-17 Robert L Hirsch Space charge controlled vacuum pump
US3924967A (en) * 1974-03-22 1975-12-09 Varian Associates Sublimation vacuum pump having a removable gas permeable condenser
WO2001043162A3 (de) * 1999-12-08 2002-07-25 Max Planck Gesellschaft Ionengetterpumpe

Also Published As

Publication number Publication date
NL282934A (enrdf_load_stackoverflow)
GB951866A (en) 1964-03-11
FR1306718A (fr) 1962-10-19

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