US3764266A - Pump for producing a vacuum free of hydrogen - Google Patents

Pump for producing a vacuum free of hydrogen Download PDF

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Publication number
US3764266A
US3764266A US00150656A US3764266DA US3764266A US 3764266 A US3764266 A US 3764266A US 00150656 A US00150656 A US 00150656A US 3764266D A US3764266D A US 3764266DA US 3764266 A US3764266 A US 3764266A
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United States
Prior art keywords
pump
hydrogen
filament
pumps
producing
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Expired - Lifetime
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US00150656A
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English (en)
Inventor
Y Murakami
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Toshiba Corp
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Tokyo Shibaura Electric Co Ltd
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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

Definitions

  • a pump for producing a vacuum free of hydrogen comprising an incandescent filament for dissociating hydrogen molecules into hydrogen atoms; an oxidizing agent disposed near the filament and having at least its surface formed of metal oxides so as to oxidize mainly said dissociated hydrogen atoms into H and an exhaust means for drawing out vapors of H 0 produced on said oxidizing agent.
  • Accumulation pumps such as getter pumps, cryogenic pumps and sorption pumps for adsorbing or condensing gas molecules to an adsorbent or a cold surface so as to remove them from the gaseous phase
  • Ion pumps for exciting or ionizing gas molecules by energetic electrons so as to bury them into the surface layer of a material.
  • the pump of this invention comprises an incandescent filament for dissociating hydrogen molecules into hydrogen atoms; an oxidizing agent disposed near the filament and having at least its surface formed of metal oxides; and an exhaust means for removing vapors of H 0 obtained by the oxidation reaction on said oxidizing agent.
  • FIG. 1 is a sectional view of a pump according to an embodiment of this invention.
  • FIG. 2 is a sectional view on line 11-11 of FIG. 1;
  • the annular space 8a is so designed as to reduce a temperature gradient as much as possible in order to prevent certain gases from being released from or struck on the upper part of the exhaust means 3.
  • the degree of the reaction (I) is almost unity regardless of temperature, offering far greater advantage than in the following reaction (II) where hydrogen molecules are oxidized on the surface of cuprous oxide.
  • cuprous oxide has to be heated to about 200 to 400 C. and yet reaction proceeds slowly. Further, Where hydrogen molecules are removed only by the reaction (II), gases are likely to be released from the oxide itself as well as from the walls of a vessel containing the same due to application of such high temperature, with the resultant increase in pressure.
  • the reaction of oxidizing hydrogen occurring in the pump of this invention depends to a far greater extent on the oxidation of hydrogen atoms H dissociated by the filament 5 on the surface of cuprous oxide supported on the cylindrical copper shell 6 than on the oxidation of hydrogen molecules H2 on said surface. Accordingly, the rate of total reaction is determined mainly by the surface area of the filament and the degree of dissociation of hydrogen molecules.
  • said degree of dissociation for the range between 10- and 10- torr is 0.61.0, and can be further increased by heating the filament to higher temperatures.
  • the pump of this invention Since carbon monoxide can thus be converted to easily adsorbable carbon dioxide, the pump of this invention has an increased capacity to exhaust carbon monoxide.
  • gases and vapors ready to be adsorbed to synthetic zeolite are given below in the decreasing order, the gases included in parenthesis denoting those little adsorbable to synthetic zeolite:
  • FIG. 3 is a curve diagram presenting the performance of a pump arranged as shown in FIG. 1 according to an embodiment of this invention in comparison with that of the prior art pump, with hydrogen pressure (torr) plotted on the abscissa and the pump speed for hydrogen (l./sec.) on the ordinate.
  • the curve A represents the performance of the pump of FIG. 1, showing the pump speed for hydrogen as determined when the reactor 2 was 45 mm. in inner diameter, the cylindrical copper shell 6 was 40 mm. in both diameter and axial length, and the filament 5 was 0.25 mm. in diameter and 80 mm. in total length and heated to 2000 K.
  • the curve B denotes the performance of a prior art pump indicating the pump speed for hydrogen as determined when there was not used the filament 5, but instead there was wound a tape heater about that part of the periphery of the reactor tube 2 which faced the cylindrical copper shell 6 to heat the shell 6 to 400 C.
  • a tape heater about that part of the periphery of the reactor tube 2 which faced the cylindrical copper shell 6 to heat the shell 6 to 400 C.
  • said cooling bafiie 24 consists of a hollow member 26 provided with an inlet tube 26a and outlet tube 26b of liquid nitrogen extending in opposite directions and the aforementioned heat-radiating plates 23 which are stretched across the opposite inner walls of the hallow member 26 and pointedly bent at the center in the same direction, that is, are arranged parallel with each other.
  • the lower half of the cylindrical member 20 for cooling the porous adsorbent 21 is immersed in liquid nitrogen 11 received in the heat insulation vessel 12.
  • the outer walls of the lower half of the cylindrical member are wou d wi h a shea h heater 2.5 which, when h porous adsorbent 21 is saturated with water vapor, is so designed as to heat said adsorbent 21 for degassing of water vapor, thereby rendering it ready for reuse.
  • a branched section 27 oxidizing hydrogen into water vapor extending at right angles from said upper side wall.
  • an assembly type oxidant member 28 and a replaceable filament 29 are received in said branched section 27.
  • Said oxidant member 28 is constructed by laminating a plurality of annular surface-anodized copper plate units 28a with spacers 28b interposed therebetween and inserting support rods 30 and 31 through said units 28a and bolting them into an integral body.
  • One support rod 30 is made longer than the other 31 and fitted at one end into the inner wall of a cap member 32 mounted on the flange 27a of the branched section 27 in airtight and detachable relationship.
  • the filament 29 is so disposed as to penetrate the central opening of said annular copper plate units 28a and fitted to two support plates 33 and 34 with the oxidant member 28 disposed between the support rods 30 and 31.
  • the support plate 33 facing the cylindrical member 20 is grounded therethrough and provided with a filament-supporting metal part 35 made electrically conducting and the other support plate 34 is fitted with a filament-supporting metal part 36 electrically insulated from the former metal 35.
  • the cap member 32 has a terminal 37 penetrating therethrough in airtightness. The filament 29 is supplied with electric current through said terminal 37 and pump casing.
  • the pump according to the embodiment of FIG. 4 is adapted to treat a large capacity of hydrogen, though operated in the same manner as that of FIG. 1, and further offers great operating advantage because it permits easy replacement of both filament and oxidizing agent.
  • the pump of this invention dissociates hydrogen molecules H into hydrogen atoms H by an incandescent filament and enables the hydrogen atoms to be oxidized on the surface of cuprous oxide with the degree of oxidizing reaction being unity regardless of temperature, thus eliminating the necessity of using cuprous oxide having a particularly large surface or heatng said surface to high temperatures. Accordingly, the invention is capable of evacuating hydrogen efficiently at a high rate and maintaining a low ultimate pressure.
  • the oxidizing agent consisted of a surface-anodized copper shell or plate.
  • this invention is not limited to said embodiments, but permits other types of oxidizing agent, for example, those prepared by coating the surface of other metal materials with powders of, for example, CuO or Cu O.
  • other oxidizing agents for example, nickel oxide, iron oxide or cobalt oxide, provided their dissociation pressures and vapor pressures are low enough at operating temperatures.
  • the filament may be formed of various materials such as tungsten, rhenium, platinum, and palladium which can Withstand temperatures of about 2000" K.
  • the porous adsorbent may consist of not only zeolite, but also activated alumina or charcoal.
  • porous adsorbent When such porous adsorbent is saturated with Water vapor, it can be regenerated by being heated to a temperature of about 400 C. for degassing of the adsorbed water vapor wln'ch is pumped out by a supplementary pump.
  • a physical sorption pump as an exhaust means, the heating section of the reactor should be thermally insulated from the cooling section of a gas adsorbent.
  • the filament and oxidizing agent should be located near enough to each other to allow hydrogen atoms dissociated by the filament to travel straight to the oxidizing agent.
  • a pump for selectively pumping mainly H or H O it is possible either to adsorb only H O (including that kind of H 0 which is converted from H by maintaining the adsorbent used in the foreg ing m odimen s at normal t mp r ture, or to cool the pump casing with liquid nitrogen without using an adsorbent.
  • the exhaust means used in the pump of this invention is simply intended to remove water vapor generated by oxidation reaction. It will be apparent, therefore, that in addition to the physical sorption pump used in the aforementioned embodiment, there may be used conventional pumps such as ditfusion-, getter-, sputter ion-, and molecular pumps.
  • a pump for producing a vacuum substantially free of hydrogen which comprises:
  • a pump as claimed in claim 1 wherein said layer of metal oxide consists of a plurality of annular plates bearing said metal oxide laminated together and said filament penetrates a central opening in the assembly of annular plates.
  • said trap comprises a physical sorption pump provided with an adsorption section containing a porous adsorbent and cooling means therefor.
  • the physical sorption pump is provided with a cylindrical member disposed at a position substantially heat insulated from said oxidation reactor, synthetic zeolite received in said cylindrical member, a heater for heating said synthetic zeolite, and cooling means for cooling said synthetic zeolite.
  • said trap comprises a physical sorption pump provided with a porous adsorbent, a means for cooling said adsorbent, and heat shielding plates disposed between the adsorbent and said filament.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Compressors, Vaccum Pumps And Other Relevant Systems (AREA)
US00150656A 1970-12-11 1971-06-07 Pump for producing a vacuum free of hydrogen Expired - Lifetime US3764266A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP45109561A JPS5039242B1 (es) 1970-12-11 1970-12-11

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US3764266A true US3764266A (en) 1973-10-09

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JP (1) JPS5039242B1 (es)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3986835A (en) * 1971-11-27 1976-10-19 Sinloihi Company Limited Ventilation hood for use in the preparation of labelled compounds
US4515528A (en) * 1983-07-05 1985-05-07 General Electric Company Hydrocarbon getter pump
US4645468A (en) * 1982-04-28 1987-02-24 U.S. Philips Corporation Method of removing hydrocarbons from vacuum tubes
US4671080A (en) * 1986-01-13 1987-06-09 The Boeing Company Closed cryogenic cooling system without moving parts
US4717549A (en) * 1983-04-12 1988-01-05 L'air Liquide, Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges Claude Oxygen chemical generation respiration apparatus

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP6016159B2 (ja) * 2012-12-21 2016-10-26 大学共同利用機関法人 高エネルギー加速器研究機構 非蒸発型ゲッターポンプ

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3155310A (en) * 1960-03-12 1964-11-03 Heraeus Gmbh W C Method of producting a vacuum

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3986835A (en) * 1971-11-27 1976-10-19 Sinloihi Company Limited Ventilation hood for use in the preparation of labelled compounds
US4645468A (en) * 1982-04-28 1987-02-24 U.S. Philips Corporation Method of removing hydrocarbons from vacuum tubes
US4717549A (en) * 1983-04-12 1988-01-05 L'air Liquide, Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges Claude Oxygen chemical generation respiration apparatus
US4515528A (en) * 1983-07-05 1985-05-07 General Electric Company Hydrocarbon getter pump
US4671080A (en) * 1986-01-13 1987-06-09 The Boeing Company Closed cryogenic cooling system without moving parts

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Publication number Publication date
JPS5039242B1 (es) 1975-12-16

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