US1753408A - Inductance system - Google Patents

Description

L. A. GEBHARD INDUC'IANGE SYSTEM Filed Dec. 22, 1928 M2 Sheets-Shet 1 April 8, 1930.

April 8, 1930. L. A. GEBHARD v 1,753,408

INDUCTANCE SYSTEM Filed Dec. 22, 1928 v 2 sheets-sheet 2 lll II To Source o AQ.

@ JEsAFormgr Patented Apr. 8, 1930 UNITED STATES- PATENT OFFICE LOUIS A. GEBHARD, OF WASHINGTON, DISTRICTOF (IIOLUIMIIBIA, ASSIGNORTO WIRED RADIO, INC., OF NEW YORK, N. Y., A CORPORATION OF DELAWARE INDUCTANCE SYSTEM Application filed December 22, 1928. Serial No. 327,988.

My invention relates to inductance systems in general and more specifically to inductance systems employed in thermionic tube transmitters. An object of my invention is to provide an inductance system for high frequency transmitters of the type employing thermi onic tubes having the anodes thereof cooled by a circulatory liquid.

Another object of my invention is to provide an inductance system wherein the high frequency output circuit includes the circulatory system of the cooling fluid.

Still another object of my invention is to provide an inductance system wherein the cooling fluid circulates through the high frequency inductance of an electrically balanced thermionic tube transmitting system.

A better understanding of the inductance system of my invention can be had by referring to the specification following and to the accompanying drawings wherein:

Figure 1 is a diagrammatic illustration showin the inductance system of my invention an Fig. 2 is a schematic circuit diagram showing the inductance system of my invention.

In transmitting systems employing ther mionic tubes having their anodes cooled by 80 a circulatory liquid it is essential to efliciency that the losses of high frequency energy in the cooling system be reduced to a minimum.

With the connection of the cooling fluid to and from the thermionic tubes by means of an insulated length of tubing or hose, con! siderable loss of energy occurs. This is due primarily to the high potential of high frequency energy concentrated at the points of connection. The inductance system of my invention reduces these losses to a minimum and in addition provides many, advantages, as will appear from the specification follow- The cooling liquid is associated with thermionic tubes 1 and 2 by means of helical coil 5.

Coil 5 comprises a length of metal having dual passage for conveying the cooling fluid to and from the respective tubes. C011 5 is herein illustrated as comprising individual I lengths of metal tubing which are placed parallel to each other and positioned in this manner by welding or other suitable means. This provides a single electrical conductor and a dual passage for the circulating liquid. The circulating liquid is associated with coil 5 by means of connectors 5 and 5 which conduct the liquid to and from the source of supply.

Coil 5 is so designed that the frequency charv acteristics of the inductance thereof combined with the capacity of condenser 8 provides approximately the lowest frequency at which it is desired to operate the transmit- .ter. The high frequency energy may be transferred to another circuit by Inductance 13 which may be positioned in lnductive relation to said coil 5 and electrically associated with the load circuit 14. Load circuit 14 may comprise a space radio radiating-systerm, a wired radio s stem or additional ther mionic tube ampli er circuit-s. Other coupling arrangements may be employed such as causing contact members 13"-13 to be corinected either directly or capacitively to coi 5.

When it is desired to operate the transmitter on a frequency higher than that obtained by employin coil 5 and capacity 8 alone, an auxiliary in uctance 11 is connected in parallel with coil 5 and capacity 8. This is accomplished by closing switchmembers 9 and 10. Should coil 5' and inductance 11 have like frequency characteristics the resultant frequenc characteristics when the two are connected in multiple would be the sum'of the two. Thus suppose the frequency characteristics of coil 5 and capacity 8 were such as to give an oscillation constant of 50 and that L was 10 andG was 5. Assuming that the frequency characteristics of inductance 11 were such as when employed with a capacity h'aving a value of 5 would likewise give an oscillation constant of 50.. If then inductance 11 is connected in parallel relation with coil 5 I be had b 'are employed in this illustration. The

anode circuits of thermionic tubes 1 and 2 are energized from source 16. Capacity 28 is connected to the mid-connection of coil 5 and to ground 12. Inductance 11 is associated with space radio radiating system 12,12 by coil 12. Coil 13 is provided by- ,which connections to a suitable load circuit may be had when different adjustments of frequency are not properly related to the frequency characteristics of circuit 12, 12, 12 The cathode circuits of thermionic tubes 1 .and 2 are energized from transformer 22 the latter of which is associated -with' any suitable source of alternating current. Capacities 23 are provided as bypaths for high frequency energy to ground 12. A source of control electrode biasing potential 17 supplies the proper potential to the respective control electrodes to insure the desire o erational characteristics. Thermionic tu es 1 and .2 are connected in an electrically balanced circuit arrangement, inductance 18 and capacity 27 constituting the input circuits and inductances 5-9 an capacity 8 constituting the output circuits.

' The circuits are electrically balanced by balancing condensers 20 and 21 which pro vide means for counterbalancing or neutralizing unlike characteristics of the circuits. The input circuit of thermionic tubes 1 and 2 are associated with any suitable source of high frequency encr 19 by means of condensers 25 and 26. apacit 24 is provided to offer a by-path to the high frequency energy and exclude the same from source 17.

Different adjustments in the frequency characteristics are obtained by opening or closing switch members 9 and 10.

Coil 5 comprises any suitable metal tubing and the inherent frequency characteristics of the inductance which it constitutes are not easily adjusted. Since the opposite 'ends of the coil are connected to the sockets of the thermionic tubes" and a circulatory cooling liquid is flowing therethrough, it is obvious that it would be impractical to attempt to vary the length of the tubing. In the inductance system of my invention the frequency characteristics of the circuit including 0011 5 may be easily adjusted to any desired value without disturbing the circulation of the cooling fluid.

I realize that many modifications of the inductance system of my invention are possible without de arting from the spirit of my invention. ny suitable type of'thermionictubes may be employed and any number of such tubes may be connected in suitable circuit arrangements. Similar inductances may be employed in the input circuit when a liquid cooled inductance is necessary or so desired. It is to be understood that my invention shall notbe restricted to precisely the arrangements shown in the accompanying drawings or described in the foregoing specification but only as defined by the scope of the appended claims.

What I claim as new and desire to secure by Letters Patent of the United States is as follows:

1. An inductance system comprising in combination a metallic member of helical form providing a double passage for the circulation of liquid and means provided at the electrical center of the inductance whereby said liquid may be admitted to said passage.

2. An- -inductance system comprising a helix, said helix comprising'a double passage for cooling fluids and a common passage for electrical energy.

3. An inductance system comprising a helix, said helix comprising a dual passage conductor for cooling fluids, a common passage for electrical energy and connecting members provided at the electrical center of said helix for admitting said cooling fluids.

4. In an inductance system the combination of a helix, said helix comprising metal tubing having a double passage for the circulation of a cooling fluid and means provided at the electrical center of said helix for admitting said fluid to said passages.

5. An inductance system comprising in combination a plurality of lengths of metal tubing immediately adjacent to each other comprising a single electrical conductor and comprising a plurality of conductors for the circulation of a liquid.

6. An inductance coil comprisin a helical formation of metallic tubing rovi ing a plurality of individual fluid con ucting passages immediately adjacent to each other and constituting a single electrical conductor.

7. An inductance coil comprising a helical formation of metallic tubing having a plu-' ralityof individual fluid conducting flpassages and asingle electrical passage, and uid connecting members associated with said coil at the electrical center thereof.

8. A high frequency inductance system comprisin tubing an means for associating a cooling fluid with said tubing at the electrical center of the inductance.

LOUIS A. GEBHABD.

a helical formation of metallic

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