US3187885A - Getter - Google Patents

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Publication number
US3187885A
US3187885A US239024A US23902462A US3187885A US 3187885 A US3187885 A US 3187885A US 239024 A US239024 A US 239024A US 23902462 A US23902462 A US 23902462A US 3187885 A US3187885 A US 3187885A
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United States
Prior art keywords
grains
getter
granules
surface area
porous
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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
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US239024A
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English (en)
Inventor
Hansen Norbert Ernst Fritz
Flunkert Horst
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US Philips Corp
North American Philips Co Inc
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US Philips Corp
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Publication date
Application filed by US Philips Corp filed Critical US Philips Corp
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Publication of US3187885A publication Critical patent/US3187885A/en
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    • 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
    • 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
    • H01J7/183—Composition or manufacture of getters
    • 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
    • H01J7/186—Getter supports

Definitions

  • This invention relates to a getter for electric discharge tubes and other vacuum vessels which contain zirconium, hafnium, titanium, thorium or an alloy thereof as the activemetal.
  • a getter is understood in the scope of this application both the active getter in an evacuated vacuum envelope and the not yet activated getter which contains the gettering metal or the hydride of this metal in a nonactivated form, oxide layers being present at the surface.
  • getters consist of compressed tablets, pills, or powder compressed in holders.
  • the starting material usually is obtained by granulating a larger compressed piece which contains the hydride of the gettering metal into grains having diameters smaller than 5 microns, mixed with tungsten grains of a considerably smaller diameter to prevent sintering.
  • a rather coarse sieve fraction of the granulated material then is compressed into getters.
  • the fine powder as such, is not suitable for being processed directly to getters.
  • the getter is a compact but uncompressed mass composed of a plurality of granules, hereinafter referred to as secondary grains arranged in an abrasion resistant manner, preferably in a partially perforated container.
  • Each granule is constituted of an agglomeration of grains each consisting of an active metal such as zirconium, hafnium, titanium, thorium, or an alloy thereof mixed with a refractory metal, such as tungsten or molybdenum, which prevents particles of the active metal from sintering together.
  • the latter grains, hereinafter referred to as primary grains have a specific surface area as large as possible.
  • an assembly is obtained in which the large specific surface area of the primary grains can be reached through short micropores in the secondary grains.
  • the secondary grains can be reached through macropores between these grains.
  • the getter according to the invention In the known compressed getter, substantially only a volume reaction can be operative which corresponds to the so far general conception about gettering. However, such a reaction proceeds very slowly, In the getter according to the invention, the whole surface area can be reached by the gases to be absorbed which are bound in a surface reaction. By the device according to the invention, this surface area can be reached with a pore diffusion of great velocity which can be determined by the combination of micropores and macropores. The experimentally determined diffusion velocities are in good agreement with the theory and the associated calculations. In the known getters, the micropores possibly present, offer no possibility of sufficient diffusion.
  • the minimum value for the specific surface area of the grains of the gettering material according to the invention may be about 1 to 2 m? per gram, but considerably better absorption rates are obtained with powder having a specific surface area of from 25 to 30 m per gram.
  • the specific surface area is indicated for the material which is not yet activated. As a result of the activation, a decrease by approximately 30% occurs.
  • the grains of the metal which prevents the sintering together preferably have approximately the same specific area and are present in approximately the same quantities by weight.
  • the micropores are larger also it is true, but the micropores, via which a larger part of the active surface area of the primary grains can be reached, become longer, so that the gas absorption rate is decreased. Therefore, the diameter of the secondary grains should be between a few times 10 microns and a few tenths of a millimeter.
  • the diameter of the largest granules preferably, should not exceed twice the diameter of the smallest granules. The most favorable dimensions lie between to 200 microns.
  • the secondary grains may be obtained by granulating a larger compressed piece which is obtained with pressure below 5 tons/cm. preferably 1 ton/cm.
  • the getter gives not only a higher gas absorption rate, but the degasification and also the removal of the hydrogen, if during the activation a hydride is decomposed, is much easier so that also at higher operating temperatures no noticeable hydrogen pressure is to be feared in contrast with the known devices.
  • FIGURES 1, 2 and 3 show getters according to the invention.
  • FIGURE 4 shows the location of the grains
  • FIGURE 5 shows a few gas absorption curves.
  • a nickel cylinder 1 of 4 mms. diameter and 4 mms. height is closed at both ends by wire gauze 2 and 3 respectively of chromium-nickel steel, the wire gauze consisting of crossed wires of 30 microns diameter and 30 microns spacing.
  • the cylinder 1 contains secondary grains of a sieve fraction of 100 to 200 microns diameter which is obtained as follows: Zirconium hydride powder having a specific surface area of from 2 to 30 m? per g. is mixed with tungsten powder having approximately the same specific surface area in a weight ratio of 60:40. The whole is compressed under a pressure of 1 ton/cm. and then granulatedn Of this granulate, the sieve fraction stated is used.
  • the same secondary grains 4 are provided between two wire nets 5 and 6 welded at the edge 7 as a result of which a better access to the grains is obtained.
  • the holder also includes a nickel ring 8 which can be heated by eddy currents. Further, a metal plate laid in the holder may be used.
  • FIG. 3 shows a cross-section at right angles to the axis of the getter which consists of two gauze wire rings 9 and 10 of approximately 22 mms. diameter and 12 mms. height which are welded above and below and, in addition, are formed into eight bags by eight axial parallel welds, which bags contain the grains 4.
  • FIG. 4 the secondary grains 4 are shown on an exaggerated scale as compared with FIG. 1.
  • the primary grains of zirconium hydride are designated by 12 and the primary grains of tungsten by 13.
  • the figure does not show the ratios on a real scale, it is easy to see that the micropores 14 are considerably smaller than the macropores l5.
  • the horizontal axis indicates the quantity of absorbed gas in mm./l while the vertical axis indicates the gas absorption rate in liters/sec. All measurements were carried out with carbon monoxide as a test gas, because this gas forms a large part of the residual gases in cathode-ray tubes and is in addition rather harmful.
  • Curve I relates to a device shown in FIG. 1, in which 50 mgs. of grains were used.
  • Curve II relates to a device shown in FIG. 2, in which the bag of gauze wire'had a diameter of 14 mms.
  • Curve II relates to the same powder weight as curve 1.
  • Curve III relates to two bags shown in FIG. 2 each filled with 50 mgs. of powder.
  • Curve IV relates to a getter shown in FIG. 3 filled with 500 mgs. of powder. It is easy to see from the four curves that they approach more or les an ideal rectangular curve, that is to say an ideal getter behaves so that the gas absorption rate 5 remains constant up to the entire use of the absorption capacity Q. All the curves relate to starting powder having a specific surface area of 25 m?/ g.
  • curve V which relates to a 'known device in which 26 mgs. of the same powder as for the determination of the other curves was used and in which a tablet of 3.5 mms. diameter and approximately 1 mm. thickness was pressed into a metal strip.
  • FIG. 5 clearly shows that the difference in gas absorption rate between the curves I and V is larger by more than one order of magnitude than was to be expected from the difference between the quantity of powder.
  • the highest gas absorption rate which could be reached with this device for curve V was 3X10 1/ see. with a quantity of 5 X l mm./ 1.
  • a getter for an electric discharge device comprising a porous body composed of a plurality of separate contacting granules, each of said granules being constituted of a porous agglomeration of grain of an active metal and a refractory metal, said grains having a specific surface area larger than'l m. g.
  • a getter assembly for an electric'discharge device comprising a perforated container, a porous body disposed within said container and composed of a plurality of separate contacting granules, each of said granules being constituted of a porou agglomeration of grains of anactive metal and a refractory metal, said grains having a specific surface area larger than 1 mP/g.
  • a getter for an electric discharge device comprising a porous body composed of a plurality of separate contacting granules, each of said granules being constituted of a porous agglomeration of grains of an active metal and grains of a refractory metal which prevent sintering together of said grain of active metal, said grains of active metal and said grains of refractory metal being present in substantially equal quantitie by weight and having a surface area larger than 1 m.
  • a getter for an electric discharge device comprising a porous body composed of a plurality of separate contacting granules, each of said granules being constituted of a porous agglomeration of grains of an active metal and a refractory metal, said grains having a specific surface area larger than 1 m. /g., said granules having a a diameter between a few times 10,41 and a few tenths of a millimeter.
  • a getter for an electric discharge device comprising a porou body composed of a plurality of separate contacting granules, each of said granules being constituted of a porous agglomeration of grains of an active metal and a refractory metal, said grains having a specific surface area larger than 1 m. /g., the largest granules having a diameter not exceeding twice the diameter of smaller granules.
  • a getter for an electric discharge device comprising a porous body composed of a plurality of separate contacting granules, each of said granules being constituted of a porous agglomeration of grains of an active metal and a refractory metal, said grains having a specific surface arealarger than 1 m. /g., the diameters of the granules being between about 100 and ZOO/1..
  • a getter for an electric discharge device comprising a porous body composed of a plurality of separate contacting granules, each of said granules being constituted of a porous compressed agglomeration of grains of an active metal and a refractory metal, said grains having a specific surface area larger than 1 m. g. i
  • a getter asdefined in claim 8 in which the grains have been compressed into granules at a pressure of less than 5 tons/cm.
  • a getter assembly for anelectric discharge device comprising a cylindrical container closed at both ends with a grid-like member, a getter disposed within said container and engaging said grid-like end-closing members under tension, said getter being composed of a plurality of separate contacting granules, each of said granules being constituted of a porous agglomeration of grains of an active metal and a refractory metal, said grains having a specific surface area larger than 1 m. g.
  • a getter assembly for an electric discharge device comprising a porous pliable container, a porous getter disposed within said container under slight compression, said getter being composed of a plurality of separate contacting granules, each of said granules being constituted of a porous agglomeration of grains of an active metal and a refractory metal, said grains having a specific surface area larger than 1 m. g.
  • a getter assembly as claimed in claim 12 in which a metal plate is disposed within said container with said granules.

Landscapes

  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Gas Separation By Absorption (AREA)
  • Compressors, Vaccum Pumps And Other Relevant Systems (AREA)
  • Common Detailed Techniques For Electron Tubes Or Discharge Tubes (AREA)
  • Vessels, Lead-In Wires, Accessory Apparatuses For Cathode-Ray Tubes (AREA)
  • Solid-Sorbent Or Filter-Aiding Compositions (AREA)
US239024A 1961-11-21 1962-11-20 Getter Expired - Lifetime US3187885A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DEN20851A DE1224845B (de) 1961-11-21 1961-11-21 Gasbinderanordnung fuer Elektronenroehren und andere Vakuumgefaesse

Publications (1)

Publication Number Publication Date
US3187885A true US3187885A (en) 1965-06-08

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Family Applications (1)

Application Number Title Priority Date Filing Date
US239024A Expired - Lifetime US3187885A (en) 1961-11-21 1962-11-20 Getter

Country Status (7)

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US (1) US3187885A (en, 2012)
BE (1) BE625037A (en, 2012)
CH (1) CH423002A (en, 2012)
DE (1) DE1224845B (en, 2012)
DK (1) DK108584C (en, 2012)
GB (1) GB1011259A (en, 2012)
NL (1) NL285519A (en, 2012)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3422299A (en) * 1964-07-09 1969-01-14 Westinghouse Electric Corp Fluorescent lamp having an integral mercury-vapor pressure control assembly with amalgam-forming metal and amalgam stabilizing means
US3496400A (en) * 1967-02-24 1970-02-17 Edwards High Vacuum Int Ltd Cathode arrangements for getter ion pumps
US3504215A (en) * 1967-11-30 1970-03-31 Westinghouse Electric Corp Planar fluorescent lamp with integral amalgam type mercury-vapor pressure control component
US4272259A (en) * 1976-07-21 1981-06-09 Union Carbide Corporation Gas gettering system
US20060197428A1 (en) * 2005-02-21 2006-09-07 Takeshi Tonegawa Electron devices with non-evaporation-type getters and method for manufacturing the same

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
IT1110295B (it) * 1979-02-05 1985-12-23 Getters Spa Lega ternaria getterante non evaporabile particolarmente per l'assorbimento di acqua e vapore d'acqua in barre combustibili di reattori nucleari
IT1283484B1 (it) * 1996-07-23 1998-04-21 Getters Spa Metodo per la produzione di strati sottili supportati di materiale getter non-evaporabile e dispositivi getter cosi' prodotti

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2404803A (en) * 1941-01-25 1946-07-30 Western Electric Co Space discharge device
DE886788C (de) * 1945-02-03 1953-10-05 Lorenz C Ag Hochaktives Getter
US2855368A (en) * 1953-09-30 1958-10-07 Philips Corp Method of producing a non-vaporizing getter
FR1178495A (fr) * 1956-05-19 1959-05-11 Egyesuelt Izzolampa Procédé d'obtention de corps métalliques en tungstène contenant du dioxyde de thorium
US3082174A (en) * 1959-11-17 1963-03-19 North American Phillips Compan Method of manufacturing a non-evaporating getter and getter made by this method

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL93264C (en, 2012) * 1953-09-30

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2404803A (en) * 1941-01-25 1946-07-30 Western Electric Co Space discharge device
DE886788C (de) * 1945-02-03 1953-10-05 Lorenz C Ag Hochaktives Getter
US2855368A (en) * 1953-09-30 1958-10-07 Philips Corp Method of producing a non-vaporizing getter
FR1178495A (fr) * 1956-05-19 1959-05-11 Egyesuelt Izzolampa Procédé d'obtention de corps métalliques en tungstène contenant du dioxyde de thorium
US3082174A (en) * 1959-11-17 1963-03-19 North American Phillips Compan Method of manufacturing a non-evaporating getter and getter made by this method

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3422299A (en) * 1964-07-09 1969-01-14 Westinghouse Electric Corp Fluorescent lamp having an integral mercury-vapor pressure control assembly with amalgam-forming metal and amalgam stabilizing means
US3534212A (en) * 1964-07-09 1970-10-13 Westinghouse Electric Corp Fluorescent lamp having an integral mercury-vapor pressure control assembly with segmented amalgam-forming metal
US3496400A (en) * 1967-02-24 1970-02-17 Edwards High Vacuum Int Ltd Cathode arrangements for getter ion pumps
US3504215A (en) * 1967-11-30 1970-03-31 Westinghouse Electric Corp Planar fluorescent lamp with integral amalgam type mercury-vapor pressure control component
US4272259A (en) * 1976-07-21 1981-06-09 Union Carbide Corporation Gas gettering system
US20060197428A1 (en) * 2005-02-21 2006-09-07 Takeshi Tonegawa Electron devices with non-evaporation-type getters and method for manufacturing the same
EP1696451A3 (en) * 2005-02-21 2008-03-12 Futaba Corporation Electron devices with non-evaporation-type setters and methods for manufacturing the same
US7586260B2 (en) 2005-02-21 2009-09-08 Futaba Corporation Electron devices with non-evaporation-type getters and method for manufacturing the same
CN1848352B (zh) * 2005-02-21 2011-02-09 双叶电子工业株式会社 电子装置及其制造方法、吸气剂及其处理方法

Also Published As

Publication number Publication date
DE1224845B (de) 1966-09-15
GB1011259A (en) 1965-11-24
DK108584C (da) 1968-01-08
CH423002A (de) 1966-10-31
BE625037A (en, 2012)
NL285519A (en, 2012) 1965-02-10

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