US1572882A - Hot-cathode apparatus - Google Patents

Description

Feb. 16,1926. 1,572,882

E. W. BREISCH HOT CATHODE APPARATUS Filed Nov. 9, 1918 "06600000000000000woooooooooooo 0o WITNESSES: INVENTOR A J WW fdyar W Bra/5d;

Patented Feb. 16, 1926.

UNITED STATES PATENT OFFICE.

EDGAR W. BREISCH, OF 'WILKINSBURG', PENNSYLVANIA, ASSIGNOR TO WESTING- HOUSE ELECTRIC &-MANUFACTURING COMPANY, A CORPORATION OF PENNSYL- VANIA.

'HOT-GATHODE APPARATUS.

I Application filed November 9, 1918. Serial No. 261,916.

To all whom it may concern:

Be it known that I, EDGAR W. BRnIsoH, a citizen of the United States, and a resident of Wilkinsburg, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Hot-Cathode Apparatus, of which the following is a specification.

My invention relates to electric apparatus embodying heated electrodes of the filamentary type, and it has for its object to provide means whereby electrodes of this character may be made more highly resistant to the deteriorating effects of arc action and to provide means whereby the point of impact of the working'arc thereupon may be more or less closely defined and the rela tive current flow in the two electrode leads adjusted.

The single figure of the accompanylng drawing is a partially sectional and partially diagrammatic view of a hot cathode rectlfier embodying a preferred form of my invention. I

Electric apparatus is well known wherein an are within a closed container plays upon an electrode of the filamentary type, this electrode being maintained at incandescence, as by auxiliary heating current, so as to continuously supply electrons to the surrounding space. The container of apparatus of this character may, either be highly evacuated or may be filled with inert gases, such as argon or nitrogen. For obtaining rectifying arcs, the container is preferably filled with argon, as in ordirary commercial practice. I

In the past, considerable difficulty has been encountered in constructing apparatus of this character that shall be long-lived because of the tendency of the operating arc to localize near one end of the filamentary electrode, this point of excessive arc activity being determined largely by the voltage relations of the supplycircuit. The impact of-the are near one end of the filamentary electrode resulted in the flow of the major portion of the load current through theadjacent supply lead, overloading the seal and causing rapid deterioration thereof and of the electrode structure.

I find that, by the use of an impedance device in one of the supply leads of a hot electrode, I may so adjust the potential conditions of. the entire circuit as to cause the arc to operate at any desired portion of the electrode, such as the central portion thereof. This electrode portion may then be slightly reinforced in cross section, so as to be more rugged in resisting the arc action, care being taken, however, that the reinforcement in cross section isnot such as to materially increase the conductivity of this portion of filament, thus lessening the heating and electron-emissivity thereof. By this means, the resultant current flow in the two supply leads may be equalized and maximum life of the apparatus be thus secured.

Referring to the drawing for a more detailed understanding of my invention, I shoW a closed container at 1 provided with a filamentary cathode 2 and with an anode 3 of any desired form. Alternating current for the operation of the rectifier thus constituted is supplied from a winding 4. The cathode 2 is connected across a small portion of this supply winding, as at the extreme left-hand end'thereof, by suitable leads 5 and 6, the pointof attachment of the lead 5 being made adjustable so that the heating current supplied to the filament 2 may be adjusted. The anode 3 is connected to a point near the right-hand end of the supply winding 4 by a lead 7 which may also be adjusted on the Winding 4. The lead 7 includes a load 8, such as a storage battery to be charged, and, as the rectifying action of the structure thus described is well known and understood in the art, no further detailed description thereof is deemed necessary.

Vith the elements enumerated to this point, therectifying arc exhibits a tendency to run near the extreme left-hand endof the filamentary cathode 2 as, under these conditions, the maximum operating electromotive force is made use of, namely, that existing between the extreme left-hand end of the winding 4 and the point of attachment of the lead 7. This action results in the early destruction, of the filament 2 near its point of attachment to theleadingin wire and in the overloading of the adjacent seal, and it is,-therefore, desirable the major portion of the load current attempts to flow out of the device over this lead, it encounters this impedance device, with the consequent establishment of a relatively large impedance drop. The effect of the element 9, therefore, is to force a considerable portion of the arc current through the lead 5. When the adjustment is such that the arc current is substantially equally divided between the two cathode leads, the principal zone of arc impact is toward the center'of the filament 2, as-is desired. 1

In some cases, the central portion of the filament may be slightly reinforced in' cross section, as indicated at 10, so as to withstand the cleteriorating'action of the are. This reinforcement may be accomplished by flash ing in an appropriate atmosphere but the reinforcing action should not be carried to such an extent as to do so increase the con ductivitv of the portion of the filament involved that it will not incandesce, with the attendant production of electrons, at the value of heating current whic 1 may be safely carried by the remainder of the hot cathode.

While I have shown my invention in its preferred form, it will be obvious to those skilled in the art that it is not so limited but is susceptible of various changes and modifications without departing from the' tenance of a rectlfylng are therebetween,

spirit thereof and I desire, therefore. that only such limitations shall be placed thereupon as are imposed by the prior art' or are specifically set forth in the appended claims.

I claim as my invention:

1. In electric Eapparatus, a filamentary electrode adapted to be heated, means for causing an arc to impinge upon said electrode, said are carrying a current which is a material portion of the current necessary to heat said filament, and means for, at will, modifying the point of arc impact.

In electric apparatus, a filamentary electrode adapted to be heated, means for causing an arc to impinge upon said electrode. the current from said are through said filament forming all or a substantial proportion of the current necessary to heat said filament to an operative. temperature, and means for, at will, modifying the point of arc impact. 7

3. In electric apparatus. a filamentary electrode embodying a portion of reinforced cross-section, means for causing an arc to operate upon said electrode, and potentialadjusting means for causing said are to operate principally upon said reinforced 4. In electric apparatus, a filamentary cathode adapted to be heated, means for causing an arc to'operate upon said electrode, and current-responsive means for effecting' a substantial adjustment in the'relative amounts of arc current flowing from said devicethrough the respective ends of said electrode.

5. In electric apparatus, a filamentary cathode. adapted to be heated, means for causing an arc to operate upon said electrode, the current from said are through said filament forming all or a substantial proportion of the current necessary to heat said filament to an operative temperature, and means for adjusting the relative amounts of arc current flowing from said device through the respective ends of said electrode.

6. In electric apparatus, a filamentary cathode, means for passing heating current 'therethrough, means for causing an arc to operate upon said electrode, the arc current tending to leave said electrode largely through one terminal thereof, and an ad'ust; able impedance device so disposed as to force a material portion of the arc current to leave said electrode through the remaining terminal thereof.

7. The combination with a source of alternating current, of a rectifier embodying a cathode of the filamentary type and an anode, means for connecting said cathode across a portion of said source, means for connecting said anode and cathode across another portion of said source for the main and an adjustable resistor in one of the cathode leads for determining the point of arc-impact upon said cathode.

8. The combination with an alternatingcurrent supply winding, of a rectifier embodying a hot cathode of the filamentarlyl type and an anode, connections from eac end of said cathode to relatively adjacent points near one end of said supply winding,

a connection from said anode to a point in said supply winding removed from said end of said supply winding, whereby a rect fying arc is maintained within said rectifier, and an adjustable resistor in the lead of said cathode most widely removed from said anode connection, whereby the pIlHClpal point of arc impact on said cathode may be adjusted.

9. The combination with an alternatingcurrent supply winding, of a rectifier embodying a hot cathode of the filamentary type provided with a portion of remforced cross-section and an anode, connections from each end o f'said cathode to relatively adjacent points near one end of said supply winding, a connection from said anode to a point in said supply winding removed from said end of said supply windmg, whereby a rectifying arc is maintained within said rectifier, and an adjustable resistor in the lead of said cathode most widely removed from said anode connection, whereby the principal point of arc impact on said cathode may be adjusted to lie upon said portion of reinforced cross-section. I

10. In electric apparatus, a filan'ientary cathode adapted to be heated, an anode c0- operating therewith, means for establishing an arc therebetween, and ustable current-responsive means for causing said are to impinge at will principally upon any one of a number of adjacent points intermediate the ends of said cathode.

11. An evacuated electric tube comprising an anode, a cathode co-operating therewith, means for maintaining said cathode in electronemitting condition, a pair of leads connected to said cathode at separated points and external means for elfecting a substan tial adjustment in the relative amounts of current. flowing in said leads.

Z9 12. An evacuated electric tube comprising an anode, a cathode co-operating therewith means for maintainingsaid cathode in electron-emitting condition, and a plurality of leads connected to saidv cathode at separated points, the construction and arrangement being such that substantially more current tends to .floW in one lead than in another, said one lead having an impedance sulficient to neutralize said tendency. i

13. The method of operating agaseous discharge device comprising a heated filamentary cathode, Which consists in controlling, at will, the current distribution in said cathode to prevent continuous impingement of the discharge upon one portion of said cathode. I

In testimony whereof, I have hereunto subscribed my name this 2nd day of Nov.

EDGAR W. nnniscn.

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