US2602914A - Electronic tube - Google Patents

Description

y 1952 c. H. SCHLESMAN ET AL 2,602,914

ELECTRONIC TUBE Filed April 2, 1946 3 Sheets-Sheet l J3 AATEAAWWA/E X camswrmwm L I SUPPLY L J6 -o II 0 j/ 6 a rlelon 1i Sch lesman ('[a rence Z filassbrool' July 8, 1952 c.-H. SCHLESMAN ET AL 2,502,914

ELECTRONIC TUBE Filed'April 2, 1946 5 SheetsSheet 2 4,5 I l I Z 45 July 8, 1952 c. H. SCHLESMAN ET AL 2,602,914

ELECTRONIC TUBE 3 Sheets-Sheet 5 Filed April 2, 1946 I l I L kzrletozalideklesm Lhnemel dhmmak Patented July 8, 1952 ELECTRONIC TUBE Carleton H. Schlesman, Camden, and Clarence I. v Glassbrook, Glen Echo Farm, N. J assignors to Socony-Vacuum Oil-Company, Incorporated,

a corporation of New York Application April 2, 1946, Serial No.658,898

This invention relates to the art of electrical amplification or rectification and more particularly to an improved electrical device useful either as an amplifier or as a rectifier. r

'The electrical art has long'included many examples of thermionic rectifier and amplifier tubes in which a cathode is heated to cause a stream of electrons to fiow from it to an anode. The current between the electrodes so produced has been controlled in many ways; as for example by the use of one or more grids between the cathode and the anode. I Also known to the prior art are glow discharge tubes in which a current is caused to now, not by heating the cathode, but by impressing a sufficient potential between the cathode and the anode to ionize the gas which lies between them. This latter type of device has proven advantageous in many uses but has the inherent drawback of requiring a relatively high potential across its electrodes. Hence, while it is often used as a rectifier tube, it is seldom, if ever, used as an amplifier tube. Additionally, where similar electrodes are used in a tube rectification is rarely accomplished. v u u 'In'accordance with the principles of the present invention, an entirely new type of electrical amplifier or rectifier maybe constructed, which device possesses all of theadvantages of each of the aforementioned types of amplifier or rectifier and at the same time avoids the disadvantages and possesses additional advantages that none of the previously mentioned types of device P S SS- fThe new device is capable of amplifying direct currents, low frequency, medium frequency and high frequency currents in essentially the same device; Amplifiers for" direct and low frequency currents'are verydifficult to construct and adjust such as,'for example, those used in seismographs and other apparatuses.

, The new device comprises, basically; a pair of electrodes in contact with a gas and means in dependent of the electrodes to subject the gas to a high frequency electrical field sufficient to ionizeit and cause it to glow uniformly throughout the area between the electrodes. Under such circumstances, a current is caused to flow in an external circuit between the electrodeswithout the necessity of heating one of the electrodes or of applying a potential to the electrodes. This current tends of its own volition to be unidirectional and by applying the R. F. field at the proper position along the length of the tube, controllin the pressure and power within the tube, the

7 Claims. (Cl. 321-32) direction of fiow of current can be predetermined and assured. Furthermore, the amount of this current flow can be easily and efficiently controlled by the novel use of grid or shielding arrangements. u

Since it is not necessary for the high frequency field that actuates thetube to have any direct connection with any circuit in which the tube is to operate, a single source of high frequency current can actuate a large number of tubes. The tubes may be placed in the circuits in which they are to be used without the circuit designer be coming involved in many of the problems that now arise from the practice of using a common plate power supply source. The new rectifier or amplifier device is also of interest because of its adaptability to use with a very wide rangeof frequencies and because the glow discharge necessary to cause the tube to operate generates very little heat. 1

A detailed understanding of the principles of this invention and the application of these principles to practical problems may be had by'reference to the appended drawings which illustrate preferred embodiments and uses of the new amplifier or rectifier device, and to the following description of the apparatus illustrated inthese drawings.

In the drawings:

Figure 1 is a diagrammatic illustration of a simple rectifier for converting high frequency alternating current into direct current;

Figure 2 is a diagrammatic illustration of a modified form of the tube of Figure 1, arranged in a circuit for testing sheet material;

Figure 3 is a diagrammatic illustration of a modified form of the tube of Figure 1, arranged for detecting and amplifying ultra high frequency currents;

Figure 4 is a diagrammatic illustration of a preferred form of grid for the device of Figure 3;

Figure 5 is a diagrammatic illustration of a device for determining the dielectric constant of fluids using a tube constructed according to the principles of this invention; and

Figure 6 is a diagrammatic illustration of a seriesof tubes according to this invention, all energized by a single high frequency field.

As illustrated in Figure l the broadest aspect of this invention comprises a sealed chamber ID into which extend a pair of electrodes H and I2 and in conjunction with which is some means such as a ring or coil 13 surrounding the cham her, which will provide a high frequency alternating current field capable of ionizing the gas in the chamber. This coil is supplied with power through the leads shown from a source not shown.

The chamber itself is preferably made of glass or some other non-conducting material. The ionizable medium within the chamber is preferably a gas under a relatively low pressure, for

The electrical field may be applied by a coil of wire or an external band coupled to a, source of high frequency electrical energy. In some cases this coil may take the form of a step-up transformer in which the primary only is fed by the source of high frequency current and secondary is shunted by a condenser of such size as to form a resonant circuit which will raise the field intensity within the chamber. While the drawing shows the actuating coil 13 as a single coil surrounding the chamber between the electrodes; other constructions may be used in lieu thereof. In some constructions, for example, it maybe desired to place the coil inside the cham ber l0, and even if the coil is replaced by a stepup transformer with-a secondary shunted by a condenser, this whole circuit may be pre-tuned and mounted within the chamber in. Furthermore, although the electrodes are shown at opposite ends of the chamber [9 and the actuating coilnear the center thereof, the construction may be such that the electrodes will be placed at the same end of the chamber or the chamber may have an entirely different shape from that shown in Figure 1.

Despite the factthat the electrodes as illustrated in Figure 1 are of the same shape, a unidirectional current will be generated when the high frequency field is applied to the coil l3 and this current-may be measured by connecting'the electrodes II and IE to a direct current ammter, or, as shown in the drawing, to the opposite-ends of a resistor i4 across which is connected a direct current voltmeter l5.

The output of the new device may be controlled by placing a conductive ring l6 around the chamber between the actuating coil and one of the electrodes l2 and connecting this metal ring it to the electrode IZ'through a variable condenser [1. As the capacity of the condenser isvaried it will be found that the direct current flowing between theelectrodes' H and I2 will also vary and the variation in current is quite sensitive to even a very small variation in the capacity of the condenser I l.

a In lieu of the metal ring 16 a grid may be inserted into the tube or chamber l0 between the electrodes Ii and [2, or the metal ring may take the form of a Faraday shield to prevent the flow of eddy currents therein. Also, in place of the single metal ring [6 a pair of metal rings may be'placed around the chamber ID, or a pair of grids placed within the chamber ID, and these rings or-grids, or a combination of one ring and one grid, may be connected through a condenser or through a variable impedance consisting of a condenser and an inductance or a condenser and a resistance. Any of these arrangements may be used to control the flow of direct current between the electrodes and by tuning any of these arrangements the flow of this current may be varied.

One particularly advantageous use for the new device is illustrated in Figure 2. In accordance with this figure the device is incorporated in an apparatus for inspecting sheet material. This novel apparatus inspects the sheet material both for thickness and flaws at a single operation.

Using the same principles as does the device of Figure 1, sheet material'2i maybe passed between condenser plate 22 and condenser plate 23, one of which is connected to a Faraday shield type of controlling ring 24, the other of which is connected to one electrode 25 of a tube of the type shown in Figure 1. This tube comprises a container 26 for a gas under low pressure and a second. electrode 21. It is actuated by a coil 28 supplied-with high frequency current. The electrodes 25 and 21 of the rectifier or amplifier device are connected through a fixed resistance 28' and a variable resistance 29. The recorder 30 is connected across the fixed resistor 28 and the tape may be driven at a 'speed proportional to the speed of movement of the sheet material undergoing inspection. Thus the recorder produces a running record of the inspection. A variable resistor 29 serves to; adjust the amplitude of the swing of the recorder needle and may be adjustable in a series of predetermined steps so as to change the scale on which the-recorder operates. v

A somewhat differentform of the device of this invention is shown. in Figure 3. This ;modified form of device is used for the directmeasurement by a direct current meter of ultra high frequency currents. The ultra high frequency current to be measured is fed to the device through a coaxial cable 3| with a radiating loop 32 extending into a cavity resonator 33 which surrounds one end of the rectifier or amplifier device of this invention. The rectifier or amplifier device of this invention thenconsistsofa chamber 34 with electrodes 35 and 36 extending into the ends thereof and an exciting coil 31 supplied with high frequency electrical current from a source not shown; A grid 38 mounted inside the chamber 34 and spaced from the lower-"electrode 35 will pick up suflicient of the ultra high frequency by capacitance through the chamber walls to control the directcurrent flow between the electrodes33 and 36, which current can be measured bydirecticurrent ammeter 39. A'plan view of a preferred form of the grid 38 is shown inFigure l. Because the measurement of ultra high frequency current is diflicult, and the type ofapparatus shown in Figure 3 is capable of measuring this type of current simply and directly, this particular application of the invention is of special value for this.purpose,.. a

If it is desired to ,usetheprinciples of the invention as illustrated in Figure 2 for the measurement of the dielectric constant of liquids, this may be done as illustrated in Figure 5 by use of a dielectric constant measuring cell in place of the two condenser plates 22 and 23 of Figure 2. Such a dielectric measuring cell may consist of an outer or cylindrical electrode 4| and an inner electrode 42, the space between which may be filled by the liquid 43, the dielectric of which is to be measured. The central electrode 42 may be supported by being clamped to a pair of insulating rings 44 and 45 mounted in asupport 46 which is in turn mounted on the outer electrode 4 I The supporting parts are preferably of an insulating material and shielding members 41 and 48 may be provided toprevent extraneous capacity from afiecting the operation of the device. A thermocouple 49 may be mounted in the-outer electrode so that the temperature at all times can be known. The outer electrode 4| may then be connected into the circuit shown in Figure 2 through a conductor 5i and theinner electrode into the same circuit through a conductor 52.

inwhenit is desired to use a' plurality of the rectifier or amplifier devices of this invention and to energize them from a single source of high frequency electrical current this may be done as illustrated in Figure 6 by surrounding a series of such tubes GI and 62-and 63 with a single radio frequency coil 64. As illustrated in Figure 6 control rings 65, 56 and 6'! have the form of Faraday shields and are all connected in parallel as are the three lower electrodes 68, 69 and 10 and also the three upper electrodes 1 I, 12 and 13. As illustrated in Figure 1, the action of the devices in Figure 6 is controlled by the variable condenser 14 connected between the control rings and the lower electrodes. The output of the three devices connected in parallel is passed through a variable resistor 15, a fixed resistance 16 and the operating coil 11 of a relay 18. Obviously the output of the three devices may be connected to any other device which it is desired to operate and which will operate on the amount of current which the devices are capable of producing.

While the three devices in Figure 6 have been shown as connected in parallel it is also possible to connect the devices in a circuit where they are not in parallel, with equally satisfactory results. They may, for example, be connected in a radio circuit in which the three devices take the place of the ordinary radio tubes interconnected by transformers or resistance coupling or in any other way common in a radio circuit.

With the above teaching it will be apparent to those skilled in the art that the present invention, particularly that form shown in Figure 6, finds direct application in polyphase systems wherein it is desired not to disturb the phase relationship, for example, amplification of the separation phases can be efiected.

The above applications of the present invention have been given by way of explaining it and it is to be understood that it has broader application and is to be limited only by the scope of the appended claims.

We claim:

1. A device of the type described that comprises a gas filled elongated envelope, electrodes extending into said envelope from opposite ends, an external circuit connected to said electrodes having only a load connected therein, a coil disposed about said envelope at a position between the electrodes, means for supplying alternating current to the coil to produce an electrical stress field in the gas within the envelope, a third electrode for said device disposed at a position between the coil and one end electrode, and means connected between the third electrode and the adjacent end electrode but independent of said current supplying means to control the output of said device to said load.

2. A device of the type described that comprises a gas filled elongated envelope, electrodes extending into said envelope from opposite ends, an external circuit connected to said electrodes having only a load connected therein, a coil disposed about said envelope at a position between the electrodes, means for supplying alternating current to the coil to produce an electrical stress field in the gas within the envelope, a third electrode for said device disposed at a position between the coil and-one end electrode, and im:- pedance means connected-between the third. electrodeand the adjacent end electrode but inde-'- pendent of said current supplying means tocontrol the output of said device to said load.

3. A device of the type described that comprises a gas filled elongatedenvelope', electrodes extending into said envelope from opposite ends, a coil disposed about said envelope at a position between the electrodes, means for supplying alternating current to the coil to produce an electrical stress field in the gas within the envelope, a third electrode for said device disposed at a position between the coil-and one end electrode,

and a condenser connected between the third electrode and the adjacent end electrode but independent of said current/supplyingjmeans 't control the output of said device-. 3

4. A device of the type described that comprises a gas filled elongated envelope, electrodes extending into said envelope from opposite ends, an external circuit connected to said electrodes having only a load connected therein, a coil disposed about said envelope at a position be tween the electrodes, means for supplying alternating current to the coil to produce an electrical stress field in the gas within the envelope, a third electrode for said device in the form of a band disposed around the envelope at a position between the coil and one end electrode, and means connected between the third electrode and the adiacent end electrode but independent of said current supplying means to control the output of said device to said load.

5. A device of the type described that comprises a gas filled elongated envelope, electrodes extending into said envelope from opposite ends, an external circuit connected to said electrodes having only a load connected therein, a coil disposed about said envelope at a position between the electrodes, means for supplying alternating current to the coil to produce an electrical stress field in the gas within the envelope, a third electrode for said device in the form of a grid disposed at a position between the coil and one end electrode, and means connected between the third electrode and the adjacent end electrode but independent of said current supplying means to control the output of said device to said load.

6. A device of the type described that comprises a gas filled elongated envelope, electrodes extending into said envelope from opposite ends, an external circuit connected to said electrodes hav- 111;; only a load connected therein, a coil disposed about said envelope at a position between the electrodes, means for supplying alternating current to the coil to produce an electrical stress field in the gas within the envelope, a third electrode for said device in the form of a Faraday cage disposed at a position between the coil and one end electrode, and means connected between the third electrode and the adjacent end electrode but independent of said current supplying inegns to control the output of said device to said 7. A device of the type described adapted to measure the dielectric properties of substances that comprises a gas filled elongated envelope, electrodes extending into said envelope from opposite ends, a coil disposed about said envelope at a position between the electrodes, means for supplying radio frequency current to said coil to produce an electrical stress field in the gas within the envelope, a third electrode for said device disposed at a position between the coil and one end electrode but independent of said current supplying means, a pair of additional electrodes so arranged relative to each other as to' define an area to be occupied by the substance whose dielectric properties it is desired to measure, means for connecting one of the pair of additional electrodes to the third electrode, and means for connecting the other of the pair of additional electrodes to the adjacent electrode that extends into the envelope, whereby the output of the device is a measure of the dielectric properties of the substance. I

. CARLETON H. SCHLESMAN.

CLARENCE IJGLASSBROOK.

1 REFERENCES CITED 1 'The following references are of record in the file of this patent:

8 UNITED STATES PATENTS Number Number Name Date Fischer Jan. 13, 1920 Parker Sept. 5, 1933 Kolin Mar; 7, 1939 Edgerton Apr. 4, 1939 Smith Apr. 16, 1940 Spencer May 2, 1944 FOREIGN PATENTS Country Date Great Britain Aug. 2, 19 6

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