US1850689A - Oscillation generator process and apparatus - Google Patents

Description

March 22, 1932 H. E REDEKER 1,850,689

OSCI LLATION GENERATOR PROCESS AND APPARATUS Fil ed Aug. 13, 1928 INVENTOR; 3 Harry [T Pea/eke) ATTORNEYS.

Patented Mar. 22, 1932 I ssue-8a N TEDSTATES; PATENT? oFFrcn;

HARRY n. REDEKER, or PALO ALTO, CALIFO '25 wave length, whichgencrally is nn'IA, Assicmonmo FEDERAL TELEGRAPH COMPANY, or SAN rnnnoisco; onnironnraa voo'nzeonu rition or cALIFonnIAQ OSGILLATION" GENERATOR IPBO GESS D APPARATUS Application filed August 13,1928. 1 Serial- No. 299,245.

This invention relates to the generation of high frequency waves by oscillating .arcsand has as its object to increase the frequency of operationof such devices. I

' In the past, it has been common to utilize arc converters for the generation of high frequency oscillations utilized in radio signaling apparatus. Prior to my invention, however, 'it has to the best, of my knowledge, been considered impossible to operate arc converters stably upon meters. I

Heretofore it has been considered essential to the stable operation of an arc converter, to have the element of carbon present either by utilizingelectrodes containing carbon or by supplying carbon in the enveloping atmosphere. Apparently the carbon ionizes and influences operation of the arc. periments with are converters, Ihave made the discovery that as long as the element carbon is supplied to an arcconverter in appreciable quantities, the converter cannot be operated successfullyunder a given minimum in the neighborhood of 1000 meters.v

The frequency at which a converter can oscillate is theoretically determined by the rate at which the arc in another way,it is dependent upon the rate at which the path betweenthe electrodes can de-ionize itself to interrupt flow of the current from the exciting source. of my discoveries, Iihave determined'that it is impossible to appreciablyincrease the rate at which the ionized path can ,bede ionized, as long as the element carbon is present, since the effect of carbonis apparently predomi-f nant overthat of any other element which can be supplied. I have also discovered that by eliminating carbon from the arc and in-.

troducing certain other elements it is possible to operate upon relatively short wave lengths. The preferred elements are those which are "radio active such as thorium and uranium.

Referring to the drawings: Figure 1 is a side elevational view in cross section illustrating one form of apparatus designed for carrying out the invention.

?" Fig. 2 is a plan view of a portion of one frequencies less than 1000 In my ex will scavenge itself. v Stated As :a result 1.

- of Fig. 1.

Fig.3 is across sectional view taken along the line,3-3 of Fig. 2. I k

Fig. t is a circuit diagram, illustrating the. manner in which the arc is connected. with an oscillation circuit. y

In Fig. 1 I have shown an arc converter of the longitudinal magneticfieldtype com-. prising a pair of magnetic polepieces 10 be-; tween which are disposed the anode and cathode, 11 and 12, respectively. Pole pieces 10 are providedwith the usual windings 13, and are'mounted upon a structure 14 for completing the magnetic field. To providefor adequate cooling, pole pieces 10 arepreferably provided with passageway .16 within. which tubes 17 extend, whereby cooling fluid can be introduced into tubes 17 and dis charged from passages 16. The electrodes are preferably enclosed w'thin a chamber 18 which led to enable the. atmosphere,

controlled. Veg-= about the electrodes to be sel 18 is tapped by tubes 19 and 2 1' for the introduction and removal of gases.

The electrodes may be formed ina variety ofways, providing the use of carbon, either, alone or combined, elements which I have found to be efi'ecti-veg are relatively expensive, and since a relativeis avoided Since certain ly small quantity .of' such an-element-will;

by utilizing copper electrodes and supplying to the cathode in the the additional element form ofa powder. F or example I canpi'o; 'vide the face of the cathode with a. small; depression or cavity within which the powdered sibstance s introduced. Amore convenient way to supply the additional element,

however is tO" O-I'IX1 a: cathode as; shown Figs. 2 andith In this caseI providea copper body. 22 upon which ;is threaded a ferrule 23. 1' I Ql r l in Pa sion. PC. t b y: 2 y ferrule-23, is ar-small; tip 245 whichiacontains.

the'additional elementfwhichl sup-ply. B'oth electrodes are preferably cooled by a suitable fluid, and for this purpose I have shown passages 26 Within which the tubes 27 extend for introduction of a cooling fluid.

With respect to the elements that can be employed for the generation of oscillations of relatively low wave lengths, I have discovered that the elements titanium, zirconium, thorium and uranium are each effective to secure the results of my invention. These materials are preferably utilized in powdered form and the particular element to be employed is mixed with a suitable binder and compressed toform the tip 24. The composition of the tip should be such as to render it conductive.

The atmosphere within which the arc is enveloped is preferably of an inert gas, such as hydrogen. The air or other active gases within the chamber are preferably exhausted thru tube 21 and hydrogen introduced thru tube 19. By means of suitable apparatus well known in the prior art, I maintain the hydrogen atmosphere within chamber 18 at a comparatively constant pressure, preferablv below atmospheric.

In Fig. 4 I have shown a conventional form of oscillation circuit associated with my arc converter. In this case the electrodes are supplied with current from a suitable source such as the direct current generator 28, while the oscillation circuit connected across the electrodes consists of series connected inductance and capacitance 29 and 31.

When the arc converter described above is in operation, the longitudinal magnetic field causes the are formed between the electrodes to gyrate about an axis corresponding to the axis of the magnetic field. I have found that this arrangement is particularly adapted for the production of short wave lengths when the arc is being supplied with one of the elements mentioned above. l/Vhen the arc is being supplied with the element titanium, the

converter operates stably upon wave lengths of from 400 to 500 meters. By a spectrum analysis, I determined that the titanium which I employed contained traces of hafnium. When supplying the element zirconium in the absence of other elements, except of course the copper of the electrodes, the are operated upon wave lengths of from 200 to. 400 meters, and with the element thorium the are operated upon wave lengths of from 150 to 350 meters. Best results were obtained however by supplying the element uranium which made possible operation of the I are upon wave lengths as low as meters, although the are operated best upon wave lengths of from 125 to 250 meters. It will be noted that titanium, zirconium, thor'- um and uranium are nearly electrically neutral in that they are situated near the center of the periodic table. Although all of the elements stated enabled operation of the arc upon shorter wave lengths than has herebefore been possible, the results obtained by supplying uranium were exceptionally remarkable and unexpected.

Insofar as my observations up to the present date are concerned, I have been unable to make my converter operate upon short wave lengths when the element carbon is present in appreciable quantities. Thus if the inert hydrogen atmosphere is replaced by an atmosphere of a hydrocarbon, such as alcohol vapor, the arc will no longer operate upon short wave lengths, and the supplying 0 additional, elements, as for example uranium, appear to have practically no effect upon the arc.

When it is desired to operate the are upon the shortest possible wave len hs, the size and positioning of the electro es should be such as to provide a minimum amount of capacitance between the electrodes.

I claim:

1. In an oscillation generator comprising as the source of oscillations an electric arc, the method of increasing the frequenc of operation of said are which comprises e iminating carbon from the are and supplying thereto a radio active substance.

2. In an oscillation generator comprising as the source of oscillations an electric arc, the method of increasing the frequency of operation of said are which comprises eliminating carbon from the arc and supplying uranium thereto.

3. In an oscillation generator comprising as the source of oscillations an electric arc in a longitudinal, magnetic field, the method of increasing the frequency of operation of said arcwhich comprises eliminating carbon from the arc and supplying uranium thereto.

4. An arc oscillation generator having a cathode comprising a radio active substance, together with another substance in a carbon free atmosphere, the second substance alone being incapable of producingan oscillating arc.

5. An arc oscillation generator having a cathode comprising a radio active substance and copper, said cathode operating in a carbon free atmosphere.

In testimony whereof, I have hereunto set my hand.

HARRY E. REDEKER.

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