US1814759A - Cathode structure - Google Patents
Cathode structure Download PDFInfo
- Publication number
- US1814759A US1814759A US87312A US8731226A US1814759A US 1814759 A US1814759 A US 1814759A US 87312 A US87312 A US 87312A US 8731226 A US8731226 A US 8731226A US 1814759 A US1814759 A US 1814759A
- Authority
- US
- United States
- Prior art keywords
- shell
- coating
- nickel
- cathode
- metal
- 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
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- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 24
- 239000011248 coating agent Substances 0.000 description 16
- 238000000576 coating method Methods 0.000 description 16
- 229910052759 nickel Inorganic materials 0.000 description 12
- 229910052751 metal Inorganic materials 0.000 description 11
- 239000002184 metal Substances 0.000 description 11
- 239000000126 substance Substances 0.000 description 7
- 239000000463 material Substances 0.000 description 5
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 4
- 230000003647 oxidation Effects 0.000 description 4
- 238000007254 oxidation reaction Methods 0.000 description 4
- 229910052709 silver Inorganic materials 0.000 description 4
- 239000004332 silver Substances 0.000 description 4
- DSAJWYNOEDNPEQ-UHFFFAOYSA-N barium atom Chemical compound [Ba] DSAJWYNOEDNPEQ-UHFFFAOYSA-N 0.000 description 3
- 238000010438 heat treatment Methods 0.000 description 3
- 239000011253 protective coating Substances 0.000 description 3
- 238000005086 pumping Methods 0.000 description 3
- 239000011819 refractory material Substances 0.000 description 3
- 238000000137 annealing Methods 0.000 description 2
- AYJRCSIUFZENHW-UHFFFAOYSA-L barium carbonate Inorganic materials [Ba+2].[O-]C([O-])=O AYJRCSIUFZENHW-UHFFFAOYSA-L 0.000 description 2
- BDAGIHXWWSANSR-NJFSPNSNSA-N hydroxyformaldehyde Chemical compound O[14CH]=O BDAGIHXWWSANSR-NJFSPNSNSA-N 0.000 description 2
- 229910052573 porcelain Inorganic materials 0.000 description 2
- 125000006850 spacer group Chemical group 0.000 description 2
- 229910000018 strontium carbonate Inorganic materials 0.000 description 2
- 241000282326 Felis catus Species 0.000 description 1
- 229910052788 barium Inorganic materials 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 150000004649 carbonic acid derivatives Chemical class 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 230000001627 detrimental effect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000007654 immersion Methods 0.000 description 1
- 238000010348 incorporation Methods 0.000 description 1
- 230000000266 injurious effect Effects 0.000 description 1
- 238000002955 isolation Methods 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 238000010422 painting Methods 0.000 description 1
- 238000007747 plating Methods 0.000 description 1
- LEDMRZGFZIAGGB-UHFFFAOYSA-L strontium carbonate Chemical class [Sr+2].[O-]C([O-])=O LEDMRZGFZIAGGB-UHFFFAOYSA-L 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Images
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J1/00—Details of electrodes, of magnetic control means, of screens, or of the mounting or spacing thereof, common to two or more basic types of discharge tubes or lamps
- H01J1/02—Main electrodes
- H01J1/13—Solid thermionic cathodes
- H01J1/20—Cathodes heated indirectly by an electric current; Cathodes heated by electron or ion bombardment
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10S428/00—Stock material or miscellaneous articles
- Y10S428/922—Static electricity metal bleed-off metallic stock
- Y10S428/9265—Special properties
- Y10S428/929—Electrical contact feature
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/12—All metal or with adjacent metals
- Y10T428/12493—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
- Y10T428/12535—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.] with additional, spatially distinct nonmetal component
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/12—All metal or with adjacent metals
- Y10T428/12493—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
- Y10T428/12771—Transition metal-base component
- Y10T428/12861—Group VIII or IB metal-base component
- Y10T428/12896—Ag-base component
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/12—All metal or with adjacent metals
- Y10T428/12493—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
- Y10T428/12771—Transition metal-base component
- Y10T428/12861—Group VIII or IB metal-base component
- Y10T428/12944—Ni-base component
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/12—All metal or with adjacent metals
- Y10T428/12493—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
- Y10T428/12986—Adjacent functionally defined components
Definitions
- the present invention is for a cathode structure, and relates particularly to a cathode structure of the indirectly heated type for use in thermionic tubes and the like.
- Cathodes of the indirectly heated type have been proposed for use in thermionic tubes of various types.
- I have heretofore proposed to provide a cathode structure in the form of a cylindrical metal shell fitted about a filling or spacing body of refractory material. Embedded or supported in the refractory material is a heating wire.
- Such a structure has the advantage that it may be heated, if desired,"from an alternating ourrent source.
- the metal shell of such devices has preferably been made of nickel, because the magnetic properties of that metal serves as a shield to eliminate the effects of the alternating current field of the heater current on the output current of the tube.
- alkaline earth carbonates have been proposed as a coating for the shells.
- the nickel very readily acquires an oxide coating thereon which is detrimental to the tube and which tends to insulate the alkaline earth coating from the shell, thereby preventing a free current flow between the metal and the alkaline earth substance.
- the second disadvantage arises out of the fact that the shells are usually coated with the alkaline earth compound by immersion therein before the shell is applied to the refractory central rod or spacer, whereupon the rod or spacer, when forced into the shell, sc rapes some of the alkaline earth substance in the shell loose and this collects on one end of the refractory body while more of the interior coating, with its contained moisture, is trapped between the shell and the refractory. This not only renders thorough degassification difficult, but is a menace to the heating wire, any alkaline earth substance that contacts with the heater wire attacking the wire at the temperature and under the conditions found and existing during the pumping and subsequent operation of the tube.
- the present invention proposes to eliminate these objections and provide acathode, and a method of producing the same, wherein the injurious oxidation of the shell is prevented and the alkaline earth substance applied in such manner that it is entirely out of contact with any of the heater structure.
- Fi ure 1 is a longitudinal section through a cat ode structure embodying my invention.
- Figure 2 represents a strip of metal from which the cathode shells may be made.
- Figure 3 a is a perspective view of the cathode structure.
- 5 is a cylindrical metal shell within which is a heater wire 6.
- the heater wire is mounted in the shell by suitable spacing means, such as the mass or rod of refractory material or porcelain 7 in which the wire is embedded.
- suitable spacing means such as the mass or rod of refractory material or porcelain 7 in which the wire is embedded.
- the shell is preferably formed of nickel, as hereinbefore explained, and in order to protect it against undesirable oxidation before and during the pumping of the tube in which the cathode is mounted, the metal is plated with a thin coating of a metal less like ly to form an oxide coating over itself than nickel.
- This coating is preferably silver, as silver does not so readily acquire an oxide skin or film as does the nickel.
- the emitting coating of barium or strontium carbonate or other substance is applied to the silver plated shell. This coating is designated 9.
- the heater wire and porcelain are assembled in the usual manner.
- the nickel which may be in thin strips 10, as shown in Fig. 2, may be plated with silver before or after annealing, the annealing being effected to. render the nickel pliable.
- .Pieces of the annealed and plated nickel are then bent into the form of the cathode shell and the heater structure is fitted therein.
- a coating such-as barium and strontium carbonate in water, is spread over the shell, preferably with a brush, care being taken to prevent this coating from running over the edges of the shell onto the heater structure.
- a narrow, uncoatedumargin 11 is left at each end of the shell.
- alkaline materials may be applied only where desired and only where the material can be thoroughly dried and degassified.
- barium and strontium carbonates other well known emission materials may be used.
- a cylindrical shell of nickel open at each end thereof, a refractory mass within the shell, a heating wire passing through the refractory mass, a protective coating of metal over the shell, such protective coating being more resistant to oxidation than the nickel, and a coating of emitting substance on the outside of the shell over the protective coating.
- a cathode unit adapted to be mounted and enclosed-in a thermionic tube, comprising a thin cylindrical shell of nickel open at each end and rendered proof against oxidation, a refractory mass within the cylindrical shell, a heater wire supported by the mass out of contact with the shell, and an emitting substance on the outer surfaceof-the shell.
Description
July 14, 1931. F. s. M CULLOUGH 1,314,759
CATHODE STRUCTURE Filed Feb. 10, 1926 INVENTO R MIA/flay @w Patented July 14, 1931 PAZI'ENT OFFICE FREDERICK S. MGCULLOUGH, OF EDGEWOOD, PENNSYLVANIA CATHODE STRUCTURE Application filed February 10, 1926. Serial no. 87,312.
The present invention is for a cathode structure, and relates particularly to a cathode structure of the indirectly heated type for use in thermionic tubes and the like.
Cathodes of the indirectly heated type have been proposed for use in thermionic tubes of various types. I have heretofore proposed to provide a cathode structure in the form of a cylindrical metal shell fitted about a filling or spacing body of refractory material. Embedded or supported in the refractory material is a heating wire. Such a structure has the advantage that it may be heated, if desired,"from an alternating ourrent source.
The metal shell of such devices has preferably been made of nickel, because the magnetic properties of that metal serves as a shield to eliminate the effects of the alternating current field of the heater current on the output current of the tube. For the purpose of increasing the electron emissitivity of the shell, alkaline earth carbonates have been proposed as a coating for the shells.
Two disadvantages arise from such a construction. The nickel very readily acquires an oxide coating thereon which is detrimental to the tube and which tends to insulate the alkaline earth coating from the shell, thereby preventing a free current flow between the metal and the alkaline earth substance. The second disadvantage arises out of the fact that the shells are usually coated with the alkaline earth compound by immersion therein before the shell is applied to the refractory central rod or spacer, whereupon the rod or spacer, when forced into the shell, sc rapes some of the alkaline earth substance in the shell loose and this collects on one end of the refractory body while more of the interior coating, with its contained moisture, is trapped between the shell and the refractory. This not only renders thorough degassification difficult, but is a menace to the heating wire, any alkaline earth substance that contacts with the heater wire attacking the wire at the temperature and under the conditions found and existing during the pumping and subsequent operation of the tube.
The present invention proposes to eliminate these objections and provide acathode, and a method of producing the same, wherein the injurious oxidation of the shell is prevented and the alkaline earth substance applied in such manner that it is entirely out of contact with any of the heater structure.
The invention may be readily understood by reference to the accompanying drawings which illustrate the invention more or less diagrammatically, and to the details of which my invention is not confined.
In the drawings:
Figure 2 represents a strip of metal from which the cathode shells may be made.
Figure 3 a is a perspective view of the cathode structure.
In the drawings, 5 is a cylindrical metal shell within which is a heater wire 6. The heater wire is mounted in the shell by suitable spacing means, such as the mass or rod of refractory material or porcelain 7 in which the wire is embedded. I have shown one end of the heater wire connected to the cathode at 8, but this may be changed as desired, as in some cathodes theheater wire need not connect to the shell.
The shell is preferably formed of nickel, as hereinbefore explained, and in order to protect it against undesirable oxidation before and during the pumping of the tube in which the cathode is mounted, the metal is plated with a thin coating of a metal less like ly to form an oxide coating over itself than nickel. This coating is preferably silver, as silver does not so readily acquire an oxide skin or film as does the nickel. The emitting coating of barium or strontium carbonate or other substance is applied to the silver plated shell. This coating is designated 9.
In the assembly of the structure, the heater wire and porcelain are assembled in the usual manner. The nickel, which may be in thin strips 10, as shown in Fig. 2, may be plated with silver before or after annealing, the annealing being effected to. render the nickel pliable.
.Pieces of the annealed and plated nickel are then bent into the form of the cathode shell and the heater structure is fitted therein. After the structure has been assembled, a coating, such-as barium and strontium carbonate in water, is spread over the shell, preferably with a brush, care being taken to prevent this coating from running over the edges of the shell onto the heater structure. In order to insure perfect isolation of the coating material, a narrow, uncoatedumargin 11 is left at each end of the shell.
From the foregoing, it will be evident that i J nickel or any other suitable material may be used for the shell, and that by the application of the metal coating thereto it can be protected against the formation of a semi-insulating oxide film, the metallic coat on the plate serving to more intimately unite the shell with the emitting coating. This plating of the metal not only-protectait prior to its incorporation into the tube. but also protects it during the pumping of the tube and any operation subsequent thereto.
By painting the alka ine coating on last, it is assured that the alkaline materials may be applied only where desired and only where the material can be thoroughly dried and degassified. In place of barium and strontium carbonates, other well known emission materials may be used.
What is claimed is:
1. In a cathode structure, a cylindrical shell of nickel open at each end thereof, a refractory mass within the shell, a heating wire passing through the refractory mass, a protective coating of metal over the shell, such protective coating being more resistant to oxidation than the nickel, and a coating of emitting substance on the outside of the shell over the protective coating.
'2. A cathode unit adapted to be mounted and enclosed-in a thermionic tube, comprising a thin cylindrical shell of nickel open at each end and rendered proof against oxidation, a refractory mass within the cylindrical shell, a heater wire supported by the mass out of contact with the shell, and an emitting substance on the outer surfaceof-the shell.
In testimony whereof I have hereunto set my hand.
FREDERICK S. MGCULLOUGH.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US87312A US1814759A (en) | 1926-02-10 | 1926-02-10 | Cathode structure |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US87312A US1814759A (en) | 1926-02-10 | 1926-02-10 | Cathode structure |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| US1814759A true US1814759A (en) | 1931-07-14 |
Family
ID=22204416
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US87312A Expired - Lifetime US1814759A (en) | 1926-02-10 | 1926-02-10 | Cathode structure |
Country Status (1)
| Country | Link |
|---|---|
| US (1) | US1814759A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2705293A (en) * | 1950-08-28 | 1955-03-29 | John E White | Cathode spot excitation |
| US2878410A (en) * | 1954-11-09 | 1959-03-17 | Gen Electric | Electronic tube structure |
| US2965794A (en) * | 1955-06-17 | 1960-12-20 | Varian Associates | Electron tube apparatus |
| US3495120A (en) * | 1967-03-07 | 1970-02-10 | Philips Corp | Microheating elements,more particularly for cathodes of electron tubes |
-
1926
- 1926-02-10 US US87312A patent/US1814759A/en not_active Expired - Lifetime
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2705293A (en) * | 1950-08-28 | 1955-03-29 | John E White | Cathode spot excitation |
| US2878410A (en) * | 1954-11-09 | 1959-03-17 | Gen Electric | Electronic tube structure |
| US2965794A (en) * | 1955-06-17 | 1960-12-20 | Varian Associates | Electron tube apparatus |
| US3495120A (en) * | 1967-03-07 | 1970-02-10 | Philips Corp | Microheating elements,more particularly for cathodes of electron tubes |
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