CH190259A - Indirectly heated cathode. - Google Patents
Indirectly heated cathode.Info
- Publication number
- CH190259A CH190259A CH190259DA CH190259A CH 190259 A CH190259 A CH 190259A CH 190259D A CH190259D A CH 190259DA CH 190259 A CH190259 A CH 190259A
- Authority
- CH
- Switzerland
- Prior art keywords
- oxide
- heating resistor
- dependent
- cathode according
- resistor contains
- Prior art date
Links
- 238000010438 heat treatment Methods 0.000 claims description 32
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 claims description 13
- 239000000203 mixture Substances 0.000 claims description 11
- OGIDPMRJRNCKJF-UHFFFAOYSA-N titanium oxide Inorganic materials [Ti]=O OGIDPMRJRNCKJF-UHFFFAOYSA-N 0.000 claims description 10
- 239000000919 ceramic Substances 0.000 claims description 7
- CPLXHLVBOLITMK-UHFFFAOYSA-N magnesium oxide Inorganic materials [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 claims description 7
- 239000000395 magnesium oxide Substances 0.000 claims description 6
- AXZKOIWUVFPNLO-UHFFFAOYSA-N magnesium;oxygen(2-) Chemical compound [O-2].[Mg+2] AXZKOIWUVFPNLO-UHFFFAOYSA-N 0.000 claims description 6
- XHCLAFWTIXFWPH-UHFFFAOYSA-N [O-2].[O-2].[O-2].[O-2].[O-2].[V+5].[V+5] Chemical compound [O-2].[O-2].[O-2].[O-2].[O-2].[V+5].[V+5] XHCLAFWTIXFWPH-UHFFFAOYSA-N 0.000 claims description 5
- WZECUPJJEIXUKY-UHFFFAOYSA-N [O-2].[O-2].[O-2].[U+6] Chemical compound [O-2].[O-2].[O-2].[U+6] WZECUPJJEIXUKY-UHFFFAOYSA-N 0.000 claims description 5
- 229910000484 niobium oxide Inorganic materials 0.000 claims description 5
- URLJKFSTXLNXLG-UHFFFAOYSA-N niobium(5+);oxygen(2-) Chemical compound [O-2].[O-2].[O-2].[O-2].[O-2].[Nb+5].[Nb+5] URLJKFSTXLNXLG-UHFFFAOYSA-N 0.000 claims description 5
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 claims description 5
- 229910000439 uranium oxide Inorganic materials 0.000 claims description 5
- 229910001935 vanadium oxide Inorganic materials 0.000 claims description 5
- 238000007792 addition Methods 0.000 claims description 4
- WGLPBDUCMAPZCE-UHFFFAOYSA-N Trioxochromium Chemical compound O=[Cr](=O)=O WGLPBDUCMAPZCE-UHFFFAOYSA-N 0.000 claims description 3
- LTPBRCUWZOMYOC-UHFFFAOYSA-N beryllium oxide Inorganic materials O=[Be] LTPBRCUWZOMYOC-UHFFFAOYSA-N 0.000 claims description 3
- 229910000423 chromium oxide Inorganic materials 0.000 claims description 3
- 239000000126 substance Substances 0.000 claims description 3
- 239000010936 titanium Substances 0.000 claims description 3
- FRWYFWZENXDZMU-UHFFFAOYSA-N 2-iodoquinoline Chemical compound C1=CC=CC2=NC(I)=CC=C21 FRWYFWZENXDZMU-UHFFFAOYSA-N 0.000 claims description 2
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 2
- 229910000449 hafnium oxide Inorganic materials 0.000 claims description 2
- WIHZLLGSGQNAGK-UHFFFAOYSA-N hafnium(4+);oxygen(2-) Chemical compound [O-2].[O-2].[Hf+4] WIHZLLGSGQNAGK-UHFFFAOYSA-N 0.000 claims description 2
- 229910052760 oxygen Inorganic materials 0.000 claims description 2
- 239000001301 oxygen Substances 0.000 claims description 2
- 230000001419 dependent effect Effects 0.000 claims 21
- 101100495769 Caenorhabditis elegans che-1 gene Proteins 0.000 claims 1
- 229910000287 alkaline earth metal oxide Inorganic materials 0.000 claims 1
- 239000012212 insulator Substances 0.000 claims 1
- 238000002844 melting Methods 0.000 claims 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 5
- 238000010304 firing Methods 0.000 description 3
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 2
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 2
- 239000000292 calcium oxide Substances 0.000 description 2
- ODINCKMPIJJUCX-UHFFFAOYSA-N calcium oxide Inorganic materials [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 description 2
- QDOXWKRWXJOMAK-UHFFFAOYSA-N dichromium trioxide Chemical compound O=[Cr]O[Cr]=O QDOXWKRWXJOMAK-UHFFFAOYSA-N 0.000 description 2
- 229910052749 magnesium Inorganic materials 0.000 description 2
- 239000011777 magnesium Substances 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 229910044991 metal oxide Inorganic materials 0.000 description 2
- 150000004706 metal oxides Chemical class 0.000 description 2
- 230000001590 oxidative effect Effects 0.000 description 2
- 239000000377 silicon dioxide Substances 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 230000004308 accommodation Effects 0.000 description 1
- BRPQOXSCLDDYGP-UHFFFAOYSA-N calcium oxide Chemical compound [O-2].[Ca+2] BRPQOXSCLDDYGP-UHFFFAOYSA-N 0.000 description 1
- 229910052681 coesite Inorganic materials 0.000 description 1
- 239000004020 conductor Substances 0.000 description 1
- 229910052906 cristobalite Inorganic materials 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 230000004907 flux Effects 0.000 description 1
- 238000009413 insulation Methods 0.000 description 1
- 239000012811 non-conductive material Substances 0.000 description 1
- RVTZCBVAJQQJTK-UHFFFAOYSA-N oxygen(2-);zirconium(4+) Chemical compound [O-2].[O-2].[Zr+4] RVTZCBVAJQQJTK-UHFFFAOYSA-N 0.000 description 1
- 235000012239 silicon dioxide Nutrition 0.000 description 1
- 229910052814 silicon oxide Inorganic materials 0.000 description 1
- 229910052682 stishovite Inorganic materials 0.000 description 1
- 239000004408 titanium dioxide Substances 0.000 description 1
- 229910052905 tridymite Inorganic materials 0.000 description 1
- NMEHNETUFHBYEG-IHKSMFQHSA-N tttn Chemical compound C([C@@H](C(=O)N[C@@H]([C@@H](C)CC)C(=O)N[C@@H](CC=1C=CC(O)=CC=1)C(=O)N[C@@H](CO)C(=O)N[C@@H](CC=1NC=NC=1)C(=O)N[C@@H](CC=1C=CC=CC=1)C(=O)N[C@@H](CCCCN)C(=O)N[C@@H](CCC(N)=O)C(=O)N[C@@H](C)C(=O)N[C@@H]([C@@H](C)O)C(=O)N[C@@H](C(C)C)C(=O)NCC(=O)N[C@@H](CC(O)=O)C(=O)N[C@@H](C(C)C)C(=O)N[C@@H](CC(N)=O)C(=O)N[C@@H]([C@@H](C)O)C(=O)N[C@@H](CC(O)=O)C(=O)N[C@@H](CCCNC(N)=N)C(=O)N1[C@@H](CCC1)C(=O)NCC(=O)N[C@@H](CC(C)C)C(=O)N[C@@H](CC(C)C)C(=O)N[C@@H](CC(O)=O)C(=O)N[C@@H](CC(C)C)C(=O)N[C@@H](CCCCN)C(O)=O)NC(=O)[C@H](CC(C)C)NC(=O)[C@H](CCSC)NC(=O)[C@H](CCC(O)=O)NC(=O)[C@H](CCC(O)=O)NC(=O)[C@H](CC(O)=O)NC(=O)[C@@H](NC(=O)[C@H]1N(CCC1)C(=O)[C@H](CCC(N)=O)NC(=O)[C@@H](N)[C@@H](C)O)[C@@H](C)O)C1=CC=CC=C1 NMEHNETUFHBYEG-IHKSMFQHSA-N 0.000 description 1
- 229910001928 zirconium oxide Inorganic materials 0.000 description 1
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
- H01J1/22—Heaters
Landscapes
- Compositions Of Oxide Ceramics (AREA)
- Non-Adjustable Resistors (AREA)
- Conductive Materials (AREA)
Description
Mittelbar geheizte Kathode. Um bei mittelbar beheizten Kathoden für die Kathodenheizung die volle Netzspannung unter Vermeidun g von VorsehaItwiderstän- den und Transformatoren ausnutzen zu kön nen, -,braucht man Heizkörper mit .sehr gro ssem Spannungsabfall.
Da für eine Kathode von gegebenen Abmessungen und vorge- sehriebener Arbeitstemperatur stets eine be stimmte Heizwattzahl erforderlich ist, muss bei steigender Heizspannung idie Heizstrom stärke gesenkt werden.
Wählt man als Heiz- körper einen Draht aus Metall, so muss dieser verhältnismässig lang und .dünn sein. Es ist sehr schwierig, derartige Drähte in dem Isolierkörper einer Kathode in Form von gl.a,tttn Drähten: oder in Form von Wendeln unterzubringen und dabei eine auch bei hoher Temperatur ausreichende Isolation zwischen Kathode und Heizfaden zu sichern.
Da die Unterbringung des Heizkörpers in der Ka thode durch Verringern seiner Länge sehr erleichtert wird, wäre es zweckmässig, Stoffe mit höherem spezifischen Widerstand zu be- nutzen. Als solche kommen zunächst Ge mische von Metall- oder Kohlepulver mit iso lierenden Oxyden in Betracht. Heizkörper aus solchen ,Stoffen haben sich jedoch nicht bewährt, da ihre Widerstandswerte sehr ver schieden ausfallen.
Nach der Erfindung wird als Heizwider- stand für mittelbar geh@eizte Kathoden ein keramischer Körper verwendet, der ein Ge misch von leitenden und nichtleitenden Oxy den enthält.
Die Oxyde müssen hoch schmel zen und dürfen unter denBetriebsbedingungen ihre chemische Zusammensetzung nicht än- dern. Schliesslich soll der Sauerstoffgehalt des leitenden Bestandteils ;
geringer sein als er bei Erhitzung in. Luft sein würde. Die günstigen Eigenschaften solcher l xyde be ruhen wahrscheinlich darauf, dass sie sieh mehr oder weniger gegenseitig lösen.
Da .durch wird der Einfluss der Ausgangskorn grösse des leitenden und des nichtleitenden Bestandteils verwischt,
.so @dass die aus den Oxydgemischen hergestellten Widerstands- körp.er unabhängig von der Ausgangskorn- grösse bei gleichem Mischungsverhältnis und gleichen Brennbedingungen auch ,gleiche Wi derstandswerte haben.
Gute Heizwiderstände werden zum Bei spiel aus einer Mischung von niederem T.i- tanoxyd, dessen atomares Verhältnis von Ti : 0 zwischen 1 : 2 und 1 :
1 liegt, mit Berylliumoxyd Be0, Calciumoxyd CaO und insbesondere Magnesiumoxyd Mg0,
einer Mischung von Vanadinoxyd V205 oder von Nioboxyd N'203 mit Aluminiumoxyd A1203 oder Chromoxyd Cr2O3 und einer Mischung von Uranoxyd U02 mit Thoroxyd T102, Zir- konoxyd Zr0,2, Hafniumoxyd Hf02 oder Kie selsäure SiO2 erhalten.
Besonders bewährt hat sich das Gemisch eines niederen Titan oxydes mit Magnesiumoxyd. Es ist selbst verständlich möglich, .gleichzeitig mehrere Stoffeder genannten Art zu verwenden,
zum Beispiel Aluminiumoxyd und Magnesium.- oxyd zusammen mit Titanoxyd oder Alu- miniumoxyd und Mabgnesiumoxyd zusammen mit Titanoxyd ' und Vanadinoxyd oder die Zusammenstellung anders zu wählen, als es oben beispielsweise angegeben ist.
Als isolierender Bestandteil kann auch noch Tautaloxyd Ta20, dienen. Zuschläge von Siliziumoxyd oder andern Flussmitteln geben eine erhöhte mechanische Festigkeit. Der Widerstand der Heizkörper kann will kürIich durch entsprechende Bemessung des Mengenverhältnisses zwischen den leitenden und,den nichtleitenden Bestandteilen gewählt werden.
Der keramische Körper kann zum Beispiel die Form eines Stabes, eines Rohres oder auch einer Wendel haben.
Die leitenden niederen Metalloxyde gehen beim Brennen in Luft leicht in nichtleitende höhere Oxyde über. Um leitende Körper zu erhalten, ist es ,daher erforderlich, in redu zierender Umgebung zu brennen. Man kann dann auch von den nichtleitenden oder schlecht leitenden höheren Oxyden, zum Bei spiel U508, ausgehen und sie beim Brennen in Idas leitende niedrige Metalloxyd verwan deln.
Die weitgehende Aufteilung .des lei tenden Werkstoffes in dem nichtleitenden kann noch dadurch begünstigt werden, @dass nacheinander erst in oxydierender und ,dann in reduzierender Umgebung gebrannt wird. Die unterschiedlichen Polaritäten der Mi- schungsbestan.dteile, zum Beispiel Magnesium- oxyd und Titanoxyd,
führen in oxydierender Umgebung bei hoher Temperatur zu einem völlig andern Körper, zum Beispiel dem .gut isolierenden Magnesiumtitanat. Behandelt man diesen Körper jetzt nachträglich in redu- zierender Umgebung, so wird :
das reduzier bare Oxyd, also zum Beispiel das Titan- dioxyd Ti02 des M.agnesiumtitanats, zu einem leitenden niederen Oxyd reduziert,
das nun in äusserst feinem Zustande in dem oxy- dischen Körper verteilt ist. Durch Wahl einer entsprechenden Temperatur bei dem reduzierenden Brennen kann der Wider standswert der fertigen Widerstandskörper noch in geringen Grenzen geändert' werden.
Indirectly heated cathode. In order to be able to use the full mains voltage for the cathode heating with indirectly heated cathodes while avoiding resistors and transformers, you need radiators with a very large voltage drop.
Since a certain number of heating watts is always required for a cathode of given dimensions and specified working temperature, the heating current must be reduced as the heating voltage increases.
If you choose a metal wire as the heating element, it must be relatively long and thin. It is very difficult to accommodate such wires in the insulating body of a cathode in the form of gl.a, tttn wires: or in the form of coils and to ensure adequate insulation between cathode and filament even at high temperatures.
Since the accommodation of the heater in the cathode is made much easier by reducing its length, it would be advisable to use materials with a higher specific resistance. As such, mixtures of metal or carbon powder with insulating oxides are initially considered. However, radiators made from such materials have not proven their worth, as their resistance values are very different.
According to the invention, a ceramic body is used as the heating resistor for indirectly heated cathodes, which contains a mixture of conductive and non-conductive oxides.
The oxides must melt high and must not change their chemical composition under the operating conditions. Finally, the oxygen content of the conductive component should be;
less than it would be if heated in air. The favorable properties of such lxides are probably due to the fact that they more or less dissolve one another.
As a result, the influence of the initial grain size of the conductive and non-conductive component is blurred,
So @that the resistance bodies produced from the oxide mixtures have the same resistance values regardless of the initial grain size with the same mixing ratio and the same firing conditions.
Good heating resistors are made, for example, from a mixture of lower T. titanium oxide, the atomic ratio of Ti: 0 between 1: 2 and 1:
1, with beryllium oxide Be0, calcium oxide CaO and especially magnesium oxide Mg0,
a mixture of vanadium oxide V205 or niobium oxide N'203 with aluminum oxide A1203 or chromium oxide Cr2O3 and a mixture of uranium oxide U02 with thoroxide T102, zirconium oxide Zr0.2, hafnium oxide Hf02 or silica SiO2.
The mixture of a lower titanium oxide with magnesium oxide has proven particularly useful. It is of course possible to use several substances of the type mentioned at the same time.
For example, aluminum oxide and magnesium oxide together with titanium oxide or aluminum oxide and magnesium oxide together with titanium oxide and vanadium oxide or the combination to be chosen differently from that given above, for example.
Tautal oxide Ta20 can also serve as an insulating component. Additions of silicon oxide or other fluxes give increased mechanical strength. The resistance of the radiators can be selected at will by appropriately dimensioning the quantitative ratio between the conductive and non-conductive components.
The ceramic body can, for example, have the shape of a rod, a tube or a helix.
The conductive lower metal oxides easily convert into non-conductive higher oxides when burned in air. In order to obtain conductive bodies, it is therefore necessary to burn in a reducing environment. You can then also start from the non-conductive or poorly conductive higher oxides, for example U508, and convert them into Ida's conductive lower metal oxide when fired.
The extensive division of the conductive material into the non-conductive material can be further promoted by firing first in an oxidizing and then in a reducing environment. The different polarities of the components of the mixture, for example magnesium oxide and titanium oxide,
lead in an oxidizing environment at high temperature to a completely different body, for example the well-insulating magnesium titanate. If you treat this body afterwards in a reducing environment, then:
the reducible oxide, e.g. the titanium dioxide Ti02 of magnesium titanate, is reduced to a conductive lower oxide,
which is now distributed in the oxidic body in an extremely fine condition. By choosing an appropriate temperature during the reducing firing, the resistance value of the finished resistor body can still be changed within small limits.
Claims (1)
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE2108544X | 1935-01-04 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CH190259A true CH190259A (en) | 1937-04-15 |
Family
ID=7985309
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CH190259D CH190259A (en) | 1935-01-04 | 1935-12-24 | Indirectly heated cathode. |
Country Status (3)
| Country | Link |
|---|---|
| US (1) | US2108544A (en) |
| AT (1) | AT150755B (en) |
| CH (1) | CH190259A (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2732512A (en) * | 1956-01-24 | briggs | ||
| US3006857A (en) * | 1959-04-13 | 1961-10-31 | Clevite Corp | Ferroelectric ceramic composition |
| US3263114A (en) * | 1960-10-26 | 1966-07-26 | Firm Egyesult Izzolampa Es Vil | Shock and vibration resistant heater for indirectly heated cathodes of radio receiving tubes |
| NL277007A (en) * | 1961-04-17 | |||
| US3948813A (en) * | 1974-12-02 | 1976-04-06 | The United States Of America As Represented By The United States Energy Research And Development Administration | Oxygen sensitive, refractory oxide composition |
| DE3436597A1 (en) * | 1984-10-05 | 1986-04-10 | Max Planck Gesellschaft | OXIDIC BODY WITH IONIC AND ELECTRONIC CONDUCTIVITY |
-
1935
- 1935-12-19 US US55195A patent/US2108544A/en not_active Expired - Lifetime
- 1935-12-23 AT AT150755D patent/AT150755B/en active
- 1935-12-24 CH CH190259D patent/CH190259A/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| US2108544A (en) | 1938-02-15 |
| AT150755B (en) | 1937-09-25 |
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