US2792517A - High-temperature getters for electronic tubes - Google Patents
High-temperature getters for electronic tubes Download PDFInfo
- Publication number
- US2792517A US2792517A US381003A US38100353A US2792517A US 2792517 A US2792517 A US 2792517A US 381003 A US381003 A US 381003A US 38100353 A US38100353 A US 38100353A US 2792517 A US2792517 A US 2792517A
- Authority
- US
- United States
- Prior art keywords
- core
- getter
- shield
- cathode
- heater
- 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
Links
- QCWXUUIWCKQGHC-UHFFFAOYSA-N Zirconium Chemical compound [Zr] QCWXUUIWCKQGHC-UHFFFAOYSA-N 0.000 claims description 8
- 229910052726 zirconium Inorganic materials 0.000 claims description 8
- 239000011810 insulating material Substances 0.000 claims description 5
- 239000003870 refractory metal Substances 0.000 claims description 3
- 239000007789 gas Substances 0.000 description 11
- 239000011248 coating agent Substances 0.000 description 6
- 238000000576 coating method Methods 0.000 description 6
- 239000000463 material Substances 0.000 description 6
- 239000000126 substance Substances 0.000 description 5
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 3
- 229910052721 tungsten Inorganic materials 0.000 description 3
- 239000010937 tungsten Substances 0.000 description 3
- 208000027418 Wounds and injury Diseases 0.000 description 2
- 229910052788 barium Inorganic materials 0.000 description 2
- DSAJWYNOEDNPEQ-UHFFFAOYSA-N barium atom Chemical compound [Ba] DSAJWYNOEDNPEQ-UHFFFAOYSA-N 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 230000006378 damage Effects 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 235000013405 beer Nutrition 0.000 description 1
- 208000014674 injury Diseases 0.000 description 1
- 238000009413 insulation Methods 0.000 description 1
- 229910052749 magnesium Inorganic materials 0.000 description 1
- 239000011777 magnesium Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000004804 winding Methods 0.000 description 1
Images
Classifications
-
- 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 electronic tubes generally, whether formed in tubular, spherical or other shape, and in particular to thermionic tubes having a hot element, usually an incandescent filament, such as a cathode or a cathode heater having a coating, usually of oxide, to improve electron emission or to serve as insulation or both.
- a hot element usually an incandescent filament, such as a cathode or a cathode heater having a coating, usually of oxide, to improve electron emission or to serve as insulation or both.
- getters which are active chemical substances, such as barium and magnesium, which combine with certain gases when heated.
- getters which are active chemical substances, such as barium and magnesium, which combine with certain gases when heated.
- the getter substances are flashed but this invention relates particularly to getters in which the substances are merely heated to temperatures below the flashing point.
- the invention is particularly useful in tubes which operate at high temperatures, such as the modern miniature tubes where most substances, such as barium, degas at the high temperature.
- the getter is near the hot element there is danger of injury to the aforesaid coating due to chemical reaction between the coating and the active getter material if they come into contact while hot.
- Objects of the invention are to remove the residual gases and keep them removed at high temperatures, to provide a thermionic tube in which the getter can be closely associated with the hot element without danger of damage to its coating, to increase the efiiciency of the getter, and generally to improve tubes of the type referred to.
- the invention involves a hollow hot element, such as a heated cathode or cathode heater, and a getter inside the hot element.
- a hollow hot element such as a heated cathode or cathode heater
- a getter inside the hot element.
- the getter is inside the heater.
- the invention in another aspect involves a tube comprising a cathode, a heater, and a getter on the side of the heater opposite the cathode.
- the getter In the case of a hollow heater the getter should be on the inner side of the heater, and in the case of a helical heater the getter is preferably disposed along its axis.
- the getter, heater and cathode With a tubular cathode, the getter, heater and cathode are preferably arranged concentrically.
- the getter should include a shield of material which is inert to the hot elements and the getter material when hot, the shield having spaces to admit gas to the getter material.
- the shield is in the form of a wire helix around a core of getter material with spaces between turns to admit gas to the getter material.
- Fig. I is a longitudinal central section of a tube built according to the present invention.
- Fig. 2 is an end view from line 2-2 of Fig. 1.
- the particular embodiment of the invention chosen for the purpose of illustration comprises a metallic envelope 1 which also serves as an anode, a metallic base ring 2 soldered to the envelope at 3, an insulating disk 4 sealed in the ring 3, a tubular cathode 5, a cathode heater 6 and a getter comprising a core 7 and a shield 8 of wire wound spirally around the core with spaces between turns.
- the heater may be any suitable type, in the illustration it is a double spiral coil.
- the core 7 is preferably formed of zirconium and the shield wire 8 of tungsten. Zirconium will not only get and keep tube gases at temperatures above 850 C. but it is an increasingly eliective getter with increasing temperature up to 1200 C.
- the getter and heater assembly is preferably made by first winding the shield wire on the getter core and then inserting the core and shield assembly into the heater coil.
- a cathode heater element comprising a coiled filament coated with a refractory insulating material, a core of a zirconium getter located within and supported by the coils of said filament and a shield of a highly refractory metal interposed between said filament and said core, said shield having an opening therein to permit access of gas to said core.
- a cathode heater element comprising a coiled filament coated with a refractory insulating material, a core of a zirconium getter located within and supported by the coils of said filament and a shield of tungsten interposed between said filament and said core, said shield having an opening therein to permit access of gas to said core.
- a cathode heater element comprising a coiled filament coated with a refractory insulating material, a core of zirconium getter located within and supported by the coils of said filament and a shield of a highly refractory metal interposed between said filament and said core, said shield comprising a wire helix around said core with spaces between turns to permit access of gas to said core.
- a cathode heater element comprising a coiled filament coated with a refractory insulating material, a core of a zirconium getter located within and supported by the coils of said filament and a shield of tungsten interposed between said filament and said core, said shield comprising a wire helix around said core with spaces between turns to permit access of gas to said core.
Description
May 14, 1957 D. o. HOLLAND HIGH-TEMPERATURE GETTERS FOR ELECTRONIC TUBES Filed Sept. 18. 1953 d n a w m D United rates Fatent HIGH-TEMPERATURE GETTERS FGR ELECTRONIC TUBES Donald 0. Holland, Newton Center, Mass., assignor to Raytheon Manufacturing Company, Newton, Mass, a corporation of Delaware Application September 18, 1953, Serial No. 381,093
4 Claims. (Cl. 313-474) This invention relates to electronic tubes generally, whether formed in tubular, spherical or other shape, and in particular to thermionic tubes having a hot element, usually an incandescent filament, such as a cathode or a cathode heater having a coating, usually of oxide, to improve electron emission or to serve as insulation or both.
In the manufacture of such tubes it is customary to remove residual gas by means of so-called getters which are active chemical substances, such as barium and magnesium, which combine with certain gases when heated. Sometimes the getter substances are flashed but this invention relates particularly to getters in which the substances are merely heated to temperatures below the flashing point. The invention is particularly useful in tubes which operate at high temperatures, such as the modern miniature tubes where most substances, such as barium, degas at the high temperature. In tubes where the getter is near the hot element there is danger of injury to the aforesaid coating due to chemical reaction between the coating and the active getter material if they come into contact while hot.
Objects of the invention are to remove the residual gases and keep them removed at high temperatures, to provide a thermionic tube in which the getter can be closely associated with the hot element without danger of damage to its coating, to increase the efiiciency of the getter, and generally to improve tubes of the type referred to.
In one aspect the invention involves a hollow hot element, such as a heated cathode or cathode heater, and a getter inside the hot element. In the case of a cathode heated indirectly, preferably the cathode is hollow, the
heater is inside the cathode and the getter is inside the heater.
In another aspect the invention involves a tube comprising a cathode, a heater, and a getter on the side of the heater opposite the cathode. In the case of a hollow heater the getter should be on the inner side of the heater, and in the case of a helical heater the getter is preferably disposed along its axis. With a tubular cathode, the getter, heater and cathode are preferably arranged concentrically. The getter should include a shield of material which is inert to the hot elements and the getter material when hot, the shield having spaces to admit gas to the getter material. Preferably the shield is in the form of a wire helix around a core of getter material with spaces between turns to admit gas to the getter material.
For the purpose of illustration a typical embodiment of the invention is shown in the accompanying drawings in which:
Fig. I is a longitudinal central section of a tube built according to the present invention; and
Fig. 2 is an end view from line 2-2 of Fig. 1.
Patented May 14, 1957 The particular embodiment of the invention chosen for the purpose of illustration comprises a metallic envelope 1 which also serves as an anode, a metallic base ring 2 soldered to the envelope at 3, an insulating disk 4 sealed in the ring 3, a tubular cathode 5, a cathode heater 6 and a getter comprising a core 7 and a shield 8 of wire wound spirally around the core with spaces between turns. While the heater may be any suitable type, in the illustration it is a double spiral coil. The core 7 is preferably formed of zirconium and the shield wire 8 of tungsten. Zirconium will not only get and keep tube gases at temperatures above 850 C. but it is an increasingly eliective getter with increasing temperature up to 1200 C. Thus by locating a getter of this kind inside the hot element (the cathode heater in the illustration) exceptionally good results are obtained. However when the getter is close to the hot element it must be shielded as aforesaid to guard against accidental contact with the hot element because of its great chemical atfinity for the coating of the hot element. For example, when using a zirconium getter with an alumina coating on the heater the reaction is 3Zr+2Al2O3=3ZrO2+4AL thereby producing gas and causing cathode leakage.
The getter and heater assembly is preferably made by first winding the shield wire on the getter core and then inserting the core and shield assembly into the heater coil.
It should be understood that the present disclosure is for the purpose of illustration only and that this invention includes all modifications and equivalents which fall within the scope of the appended claims.
I claim:
1. In an electronic tube, a cathode heater element comprising a coiled filament coated with a refractory insulating material, a core of a zirconium getter located within and supported by the coils of said filament and a shield of a highly refractory metal interposed between said filament and said core, said shield having an opening therein to permit access of gas to said core.
2. In an electronic tube, a cathode heater element comprising a coiled filament coated with a refractory insulating material, a core of a zirconium getter located within and supported by the coils of said filament and a shield of tungsten interposed between said filament and said core, said shield having an opening therein to permit access of gas to said core.
3. In an electronic tube, a cathode heater element comprising a coiled filament coated with a refractory insulating material, a core of zirconium getter located within and supported by the coils of said filament and a shield of a highly refractory metal interposed between said filament and said core, said shield comprising a wire helix around said core with spaces between turns to permit access of gas to said core.
4. In an electronic tube, a cathode heater element comprising a coiled filament coated with a refractory insulating material, a core of a zirconium getter located within and supported by the coils of said filament and a shield of tungsten interposed between said filament and said core, said shield comprising a wire helix around said core with spaces between turns to permit access of gas to said core.
References Cited in the file of this patent UNITED STATES PATENTS 2,469,626 Beers May 10, 1949
Claims (1)
1. IN AN ELECTRONIC TUBE, A CATHODE HEATER ELEMENT COMPRISING A COILED FILAMENT COATED WITH A REFRACTORY INSULATING MATERIAL, A CORE OF A ZIRCONIUM GETTER LOCATED WITHIN AND SUPPORTED BY THE COILS OF SAID FILAMENT AND A SHIELD OF A HIGHLY REFRACTORY METAL INTERPOSED BETWEEN SAID FILAMENT AND SAID CORE, SAID SHIELD HAVING AN OPENING THEREIN TO PERMIT ACCESS OF GAS TO SAID CORE.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US381003A US2792517A (en) | 1953-09-18 | 1953-09-18 | High-temperature getters for electronic tubes |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US381003A US2792517A (en) | 1953-09-18 | 1953-09-18 | High-temperature getters for electronic tubes |
Publications (1)
Publication Number | Publication Date |
---|---|
US2792517A true US2792517A (en) | 1957-05-14 |
Family
ID=23503298
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US381003A Expired - Lifetime US2792517A (en) | 1953-09-18 | 1953-09-18 | High-temperature getters for electronic tubes |
Country Status (1)
Country | Link |
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US (1) | US2792517A (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3174026A (en) * | 1962-06-20 | 1965-03-16 | Budd Co | Method and means of circumventing cathode maintenance in electron beam devices |
US4925741A (en) * | 1989-06-08 | 1990-05-15 | Composite Materials Technology, Inc. | Getter wire |
Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2469626A (en) * | 1946-06-20 | 1949-05-10 | Philips Lab Inc | High vacuum getter |
-
1953
- 1953-09-18 US US381003A patent/US2792517A/en not_active Expired - Lifetime
Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2469626A (en) * | 1946-06-20 | 1949-05-10 | Philips Lab Inc | High vacuum getter |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3174026A (en) * | 1962-06-20 | 1965-03-16 | Budd Co | Method and means of circumventing cathode maintenance in electron beam devices |
US4925741A (en) * | 1989-06-08 | 1990-05-15 | Composite Materials Technology, Inc. | Getter wire |
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