US3686474A - Vacuum pumps - Google Patents

Vacuum pumps Download PDF

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Publication number
US3686474A
US3686474A US39565A US3686474DA US3686474A US 3686474 A US3686474 A US 3686474A US 39565 A US39565 A US 39565A US 3686474D A US3686474D A US 3686474DA US 3686474 A US3686474 A US 3686474A
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US
United States
Prior art keywords
bundle
filaments
liquid
vacuum pump
vapor
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
US39565A
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English (en)
Inventor
Basil Dixon Power
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.)
BOC Group Ltd
Original Assignee
British Oxigen Ltd
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 British Oxigen Ltd filed Critical British Oxigen Ltd
Application granted granted Critical
Publication of US3686474A publication Critical patent/US3686474A/en
Anticipated expiration legal-status Critical
Expired - Lifetime 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
    • F04F—PUMPING OF FLUID BY DIRECT CONTACT OF ANOTHER FLUID OR BY USING INERTIA OF FLUID TO BE PUMPED; SIPHONS
    • F04F9/00—Diffusion pumps
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B3/00—Ohmic-resistance heating

Definitions

  • the present invention provides a vapor vacuum pump which is as claimed in the appended claims.
  • the filaments may all be in parallel with each other and with the longitudinal axis of the bundle, or they may be twisted or interwoven.
  • the bundle may be formed of two ormore layers-of filaments, in which the filaments in each layer are of different composition, structure or assembly. 1
  • the electroconductive filaments may be made of a resistive metal or of insulation material coatedwith resistive material.
  • the electroconductive filaments may be combined with non-conductive filaments in the same bundle, and the proportion, size or other parameters of the non-conductive and/or electroconductive filaments can be chosen so that the composite bundle presents a'desired resistance of the flow of electrical current along the length of the bundle. By this means, when electric current is passed along the length of the bundle, Joule heat is released which is effective to vaporize liquid flowing along the length of the bundle.
  • the cross-sectional shape of the bundle is immaterial, although particular shapes and configuration may be desired for some applications.
  • the filaments composing the bundle are fine, they present a large surface area which is contacted by the liquid, so that when the surfaces of the filaments become heated by Joule heating there is only a relatively small temperature difference between the surfaces of the filaments and the liquid flowing along the bundle.
  • the closely spaced filaments provide a large number of capillary ducts which extend partially or completely along the length of the bundle so as to result in the rapid distribution through the bundle of the liquid to be vaporized.
  • the degree of compaction of the bundle is such as to provide the required capillary eflect while at the same time permitting the resultant vapor to pass to the exterior of the bundle without applying disruptive forces to the bundle.
  • FIG. 1 is a diagrammatic view of a vapor vacuum pump of the present invention in which, the bulk of the operating liquid is located remotely from the vaporizer;
  • FIG. 2 is a diagrammatic view of a large second vapor vacuum pump of the invention
  • FIG. 3 is a diagrammatic axial view of a helical vaporizer for use in the pump shown in FIG. 2;
  • FIG. 4 is a diagrammatic sectional view of a form of vaporizer which is an alternative to that form illustrated in FIG. 2 or FIG. 3, and
  • FIG. 5 represents axial sections of four different forms of vaporizer for use in pumps of the present invention.
  • the vapor condensed on the inner walls of a water-cooled casing 2 flows into a reservoir 4 from which it flows at a controlled rate through a valve 6 to a vaporizer 8 which is adapted to be force-fed (in this case under the force of gravity) with the liquid to be vaporized.
  • a hydrostatic head is provided to carry the operating liquid into the vaporizer 8.
  • the vapor produced by the vaporizer 8 is emitted from nozzles 10 and 12 usual with vapor vacuum pumps.
  • the vapor entrains molecules of the gas being evacuated from a system coupled to a flange 14 at the upper end of casing 2.
  • the pumped gas leaves thepump by way of an outlet 16, which may be connected to the inlet of a second pump (not shown) connected in cascade and using the same or a different working fluid.
  • the pumps of the present invention have the conworking liquid is being heated at any one time. This enables the pump to be fully operational shortly after being energized, and to be opened to the atmosphere,-
  • valve 6 In order to cool the pump quickly, the valve 6 is either opened fully to flood the vaporizer 8 with relatively cold liquid after the supply of heating current has been stopped, or closed to stop further liquid reaching the vaporizer, closure taking place shortly before the flow of heating current is stopped. With either mode of shut-down, the vaporizer stops emitting vapor relatively soon after the pump is deenergized.
  • a vaporizer 8 is incorporated in a vapor nozzle 18.
  • Liquid to be vaporizer is v upper end of the vaporizer 8 passes downwardly through it under both gravitational and capillary forces.
  • the vaporizer 8 is electrically heated, although the cables by which the heating current is supplied are omitted from the drawing for clarity.
  • the resultant vapor issuing from the external surfaces of the vaporizer 8 emerges from the nozzle 18 through a discharge opening 24.
  • the rate at which liquid is supplied to the nozzle is closely related to the amount of electrical power supplied to it so that vapor of the right quality emerges from the outlet 24.
  • the vaporizer 8 shown in FIG. 3 may be used to replace the longitudinal filament type shown in FIG. 2.
  • the bundle 26 of filaments is of rectangular cross-section and is wrapped in a helical groove in a support 28.
  • the base of the groove is in communication with an axial passage 30 by a series of passages 32.
  • Liquid enters the upper end of the axial passage 30 through an inlet 34 and then passes into the interior of the bundle 26 through the passages 32.
  • the passages 32 communicate with the bundle at discrete intervals, capillary forces are effective to saturate the bundle 26 uniformly with the liquid to be vaporized.
  • current is passed along the length of the bundle 26. Either the bundle 26 is insulated from the support 28 or the support is of insulation material.
  • the vaporizer 8 shown in FIG. 4 is an alternative to that illustrated in FIG. 3.
  • the main difference is that the cross-section of the bundle of filaments alters along the length thereof.
  • the overall cross-sectional area of the bundle decreases as the liquid descends so that the amount of heat released per unit volume of the bundle increases as the cross-sectional area of the bundle is restricted.
  • the splayed-out lower end of the bundle 26 enables the vapor to escape easily from the interior of the bundle without exerting disruptive forces thereon.
  • the vapor then emerges from the outlet 24 and functions conventionally.
  • the means by which the bundle 26 is heated are again not illustrated for clarity.
  • the splayed-out end 42 is provided to increase the spacing between the filaments and thus enable the liquid to be vaporized to enter the interstitial ducts more easily than if the lower end were kept tightly compacted.
  • all the filaments 40 are intended to be of electroconductive material, the plates 36 and 38 acting as electrodes by which heating current can be passed along the length of the bundle of filaments.
  • FIG. 5(b) which, like FIGS. 5(a) and 5(d) is a scrap sectional view of the cylindrical portion of a bundle shaped similarly to that illustrated in FIG. 5(a)
  • the illustrated broken lines 44 are intended to represent filaments of electrical insulation material which are non-conducfilaments 44 which in turn is enclosed by a layer of conductive filaments 40.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Compressors, Vaccum Pumps And Other Relevant Systems (AREA)
  • Resistance Heating (AREA)
US39565A 1969-05-27 1970-05-21 Vacuum pumps Expired - Lifetime US3686474A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB2682969 1969-05-27

Publications (1)

Publication Number Publication Date
US3686474A true US3686474A (en) 1972-08-22

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ID=10249923

Family Applications (1)

Application Number Title Priority Date Filing Date
US39565A Expired - Lifetime US3686474A (en) 1969-05-27 1970-05-21 Vacuum pumps

Country Status (4)

Country Link
US (1) US3686474A (enrdf_load_stackoverflow)
DE (1) DE2025465A1 (enrdf_load_stackoverflow)
FR (1) FR2048853A5 (enrdf_load_stackoverflow)
GB (1) GB1313138A (enrdf_load_stackoverflow)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3781518A (en) * 1972-06-29 1973-12-25 British Oxygen Co Ltd Vacuum pumps
US3998738A (en) * 1972-11-22 1976-12-21 Boc Limited Vacuum drying and degassing
US4020321A (en) * 1974-03-14 1977-04-26 Boc Limited Electric heaters
US4373868A (en) * 1976-07-06 1983-02-15 Varian Associates, Inc. Diffusion pump for leak detector
US5993166A (en) * 1996-08-28 1999-11-30 The Boc Group Plc Diffusion pumps having an integrated reservoir for the working fluid
US12338144B2 (en) * 2017-06-30 2025-06-24 Ohio University Decontamination of fluids via joule-heating

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB496788A (en) * 1937-03-04 1938-12-06 Eugene Vacheron An improved air humidifier
US2140516A (en) * 1936-10-15 1938-12-20 Cowan Harry Electrical steam generator
US2501276A (en) * 1945-06-14 1950-03-21 Eastman Kodak Co Vacuum production apparatus
US3344257A (en) * 1967-09-26 Electrically powered fluid heater
US3344979A (en) * 1965-08-06 1967-10-03 William T Chester Diffusion-pump construction
US3346718A (en) * 1965-07-27 1967-10-10 Gerald J Cooley Electrically heated cryogenic liquid vaporizing apparatus
CA814547A (en) * 1969-06-03 Schladitz-Whiskers A.G. Method and apparatus for heating fluids

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3344257A (en) * 1967-09-26 Electrically powered fluid heater
CA814547A (en) * 1969-06-03 Schladitz-Whiskers A.G. Method and apparatus for heating fluids
US2140516A (en) * 1936-10-15 1938-12-20 Cowan Harry Electrical steam generator
GB496788A (en) * 1937-03-04 1938-12-06 Eugene Vacheron An improved air humidifier
US2501276A (en) * 1945-06-14 1950-03-21 Eastman Kodak Co Vacuum production apparatus
US3346718A (en) * 1965-07-27 1967-10-10 Gerald J Cooley Electrically heated cryogenic liquid vaporizing apparatus
US3344979A (en) * 1965-08-06 1967-10-03 William T Chester Diffusion-pump construction

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
Instant Hot Water Flows from Cold Water Pipe, Popular Science , July, 1961, pp. 44 46 *

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3781518A (en) * 1972-06-29 1973-12-25 British Oxygen Co Ltd Vacuum pumps
US3998738A (en) * 1972-11-22 1976-12-21 Boc Limited Vacuum drying and degassing
US4020321A (en) * 1974-03-14 1977-04-26 Boc Limited Electric heaters
US4373868A (en) * 1976-07-06 1983-02-15 Varian Associates, Inc. Diffusion pump for leak detector
US5993166A (en) * 1996-08-28 1999-11-30 The Boc Group Plc Diffusion pumps having an integrated reservoir for the working fluid
US12338144B2 (en) * 2017-06-30 2025-06-24 Ohio University Decontamination of fluids via joule-heating

Also Published As

Publication number Publication date
GB1313138A (en) 1973-04-11
DE2025465A1 (enrdf_load_stackoverflow) 1970-12-23
FR2048853A5 (enrdf_load_stackoverflow) 1971-03-19

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