US2593429A - Gas filled electric discharge device - Google Patents

Description

April 22, 1952 c, H. FOULKES GAS FILLED ELECTRIC DISCHARGE DEVICE Filed Aug. 7, 1947 I I 7 M W 2 w fm m -2 M A B W W -2 w A Horney Patented Apr. 22, 1952 UNITED STATES PATENT OFFICE.

GAS FILLED ELECTRIC DISCHARGE DEVICE Christopher Henry Foulkes, London, England, assignor to International Standard Electric Corporation, New York, N. Y., a corporation of Delaware Application August 7, 1947, Serial No. 766,910

In Great Britain September 30, 1946 Ihe present invention relates to gas filled electric discharge devices having a plurality of electrodes to form discharge gaps, the discharge across one of said gaps being arranged to reduce the striking voltage across another of said gaps.

It is well known that in order to initiate a discharge between electrodes in a gaseous atmosphere a minimum voltage must be set up between the electrodes. This striking voltage is dependent on the dimensions of the gap between the 1 each containing a further electrode to form with electrodes, the nature and pressure of the gaseous the first mentioned saidelectrode a discharge gap atmosphere and the number of charges particleswithin said compartment and passages for ions ions or electrons-present in the vicinity of the and/or electrons in the dividing walls between discharge gap. When once the discharge has 7 said compartments.

been struck, a much lower interelectrodevoltage 1,5 Particular embodiments of the present invenis required to maintain it. Furthermore, if there tion will now be described with reference to the be another gap in the vicinity, so that'charged accompanying drawings in which:

particles from the discharge irradiate this other Fig. 1 shows diagrammatically an electrode argap, the striking voltage therefor will be reduced. rangement according to the invention.

Thus in a tube wherein a discharge is caused to Fig. 2 shows an alternative form of electrode take place between the cathode and a triggering arrangement,

electrode such that when a small current of the Fig. 3 shows a device according to the construcorder of a few microamperes is caused to flow tion of Fig. 1, and

between them the main gap striking voltage, i. e., Fig. 4 is a section through the discharge device betweenanode and cathode, may be caused to be taken along the line 44 in Fig. 3.

reduced by as much as 50 v. or more depending The electrode assembly of one embodiment as upon the magnitude of the current between the shown'in Fig. 1 comprises a metal box I enclosed triggering electrode and the cathode. on all sides except the bottom and has partitions It has been proposed to connect a number of 2 dividing it off into separate compartments. tubes comprising an anode, cathode andv trigger-1 Each partition has a small hole 3 in it, and facing ing electrode, such as the above, by external cireach hole and situated in close proximity thereto cuit elements such that when the, first tube is is an anode 4 in the form of a vertical rod or wire. made conducting, a volta e derived from its ex- The open side of the box is mounted on a mica ternal circuit is applied to the trigger electrode insulator 2A upon which are also mounted the of the next tube so as to prime it. If: now a voltanode wires. This whole assembly is mounted on age pulse is applied to the system of sufiicient a press and enclosed in a glass envelope, in any magnitude to exceed the striking voltage of a convenient known manner. primed tube, but insufficient to strike an un- The box may act as the cathode of the device, primed tube, then this primedtubeismade conand the distance between the anode 4 and the ducting. This in turn primes the next tube; so 49 partition 2 of the first unit is made smaller than that with the application of successive voltage that between the anodes and partitions of the pulses, the tubes are caused to strike one after other units. This is in order that the unit with theother. One use forsucha series of operations, the smallest distance will be the first one to strike, as described, is that of a counter for counting since this distance does in a certain measure devoltage pulses. termine the striking voltage.

To save space, a number of suitably designed The anodes are polarised to a suitable voltage units may be assembled into one envelope, the and have in series with each of them a current limit being set by the number of connecting leads limiting resistance (not shown). If now a voltwhich may be conveniently sealed into, the press age pulse of the correct amplitude is applied to of the tube. It would therefore be advantageous all the anodes, it may be caused to initiate a disif priming of successive units, could be done by some means other thanby special triggering electrodes, thereby reducing the number of; connecting leads and simplifying theextei nal; circuit.

a. tarhen e nom o coni stina ads would; e

.0.. Claims. (Cl. 313-488) achieved if a common cathode were used for all the units, or alternatively a common anode.

The present invention therefore, consists in a gas filled electric discharge device having a plurality of electrodes arranged to form discharge gaps, the discharge across one of said gaps being arranged to reduce the striking voltage across another of said gaps, in which one of said electrodes is constructed as a plurality of compartments charge between the first anode and its associated partition, because of its lower striking voltage. A proportion of the ions travelling from the anode towards the cathode may then shoot through the-aperture 3 into theanode/cathode region or the next unit. As already described, the presence of these ions will have the efiect of reducing the striking voltage of this next unit such that when another voltage pulse is applied to the system this next unit will strike. The process will continue with the application of successive pulses so as to strike successive units. This may be made use of either by visually counting the number of lighted boxes in a counting system or the information may be transferred from the load resistances and made to operate relays or other recording devices.

With a filling of neon 99%, argon 1%, at a pressure of 10 mm. of mercury, the striking voltage on an experimental tube having only three units (similar to the four unit tube portrayed in Figs. 1 and 3 with the exception that it lacks the fourth unit) was found to be as laid out in the following Table No. 1. These figures were obtained without the adjacent units being struck and are givento illustrate, in conjunction with Table No. 2, the difference in striking voltage when an adjacent unit is struck.

Table No. 1

Maintaining voltage for the currents shown below. Unit number i 0.5 i 1.0 1.5 2.0 2.. 3.0 ms. 1 ma. ma ma. ma mu.

. 1 101 61 l as I 71 72 74 7s 2 103 67 Tl 1 72 73.5 75 75.5 3 102 -1 to G7 68 7o 71 Table No 2 Striking voltage when adjacent unit is struck and conducting the currents Unit shou n bclou number 0.5 1.0 1.5 2.0 2.5 3.0 m2 ma. ma. ma. ma. ma.

Struck Striking voltage} 89 83 81 74 Struck Strikingvoltage} S 80 71 Struck...

strikililg 94 92 9o 88 so 84.5 Struc Strikingvoltage} 91 88 86 84 1 when the first unit is struck or conducting, the

striking voltage of the second unit is reduced with increasing current in the first unit. Similarly, when the second unit is struck, the striking voltage of the third unit is reduced with increasing current in the second unit and so on. It should be pointed out that previous units which are conducting other than the unit immediately before it do not afiect the primed unit. Corresponding reductions in striking voltage will be realized in a tube having more than three units such as in Figs. 1, 2 and 3 herein It will be noticed that the reduction in striking voltage is greater in going from unit 1 to unit 2 to unit 3, etc., than it is going in the reverse direction, i. e. from unit 3 to unit 2 to unit I. This is arranged by making the distance from an anode to its adjacent cathode surface less than the distance between this same anode and the previous partition. It thereby ensures that the units will become operative in one direction only with the application of successive voltage pulses.

It is easier to operate the tube, so far as the external circuit 'is concerned, if the difference between the striking voltage in the unprimed condition and maintaining voltage of the units is made as large as possible. This may be achieved by covering the surface of the partition adjacent to its operating anode with alkaline earth metals or their oxides 4A such as barium or strontium, or a mixture of these. Furthermore, gases or gas mixtures other than these mentioned may be used for the same purpose of increasing the difference in voltages, or combinations of gases or gas mixtures, together with clean or coated surfaces, may

be used to get the desired operating conditions.

Another factor afiecting the sensitivity of the device is the size of the holes in the connecting partitions. The larger the hole, the greater the sensitivity for a given current in the priming unit.

The invention is not limited to four units, furthermore, they need not be in a straight line but may be made in the form of an annulus, as shown in Fig. 2, thereby making better use of the space in the envelope. Again, although in the above description the common electrode is arranged as a cathode, it is obviously possible to make the common electrode the anode and to coat, as necessary the further electrodes, which would then serve as cathodes, with electron emmissive material.

The electrode arrangement of Fig. 1 may be mounted by means of its supporting wires 5 on a glass press 6 (Fig. 3) in a conventional tube envelope I, the cathode lead 8 being brought out at the top of the envelope. The annular arrangement of Fig. 2 is well adapted for use with an envelope having a base capable of being inserted into a tube socket.

I claim:

1. Cold cathode gas filled electron discharge device having a plurality of electrodes mounted separately from each other to form discharge gaps, in which one of said electrodes is constructed with partitions forming a plurality of compartments each containing a further electrode to form with the first mentioned said electrode a discharge gap within said compartment, said partitions having passages for either ions or electrons between said compartments.

2. Cold cathode gas filled electron discharge device having a plurality of electrodes mounted separately from each other to form discharge gaps, in which one of said electrodes comprises a rectangular metallic box with partitions forming a plurality of compartments, said box having apertures on one side, and a plurality of further electrodes each extending through one of said apertures into one of said compartments, said partitions having passages for either ions or electrons between said compartments.

3. Cold cathode gas filled electron discharge device having a plurality of electrodes mounted separately from each other to form discharge gaps, in which one of said electrodes comprises a hollow annular metallic cylinder with radial conducting partitions forming a plurality of compartments, said cylinder having apertures on one side, and a plurality of further electrodes each extendng through one of said apertures into one of said compartments, said partitions having passages for either ions or electrons between said compartments.

4. Electric discharge device according to claim 1 in which said further electrodes comprise rods of conducting material inserted into the open ends of the respective said compartments.

5. Electric discharge device according to claim 2 in which said metallic box is mounted upon an insulator member closing the apertures on said one side of the first mentioned electrode.

6. Electric discharge device according to claim 1 in which said further electrodes are mounted upon a glass press at one end of the envolpes of said device and the lead out connection for said first mentioned electrodes is taken out at the other end of said envelope.

7. Electric discharge device according to claim 1 in which the gap-defining distance between a given dividing partition and one of said further electrodes is less than the distance of each remaining further electrode from a corresponding partition.

8. Electric discharge device according to claim 1 in which said first mentioned electrode forms a cathode and said further electrodes form anodes.

9. Electric discharge device according to claim 1 in which said first mentioned electrodes forms an anode and said further electrodes form cathodes.

6 10. Electric discharge device according to claim 3 in which said annular cylinder is mounted upon an insulator member closing the other end of said cylinder.

CHRISTOPHER HENRY FOULKES.

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

UNITED STATES PATENTS Number Name Date 1,945,693 Holden Feb. 6, 1934 2,019,770 Prinz Nov. 5, 1935 2,212,921 Koros Aug. 27, 1940 2,331,398 Ingram Oct. 12, 1943 2,397,661 Hare Apr. 2, 1946 2,404,920 Overbeck "July 30, 1946 2,419,485 Desch et a1 Apr. 22, 1947 2,432,608 Desch et a1 Dec. 16, 1947

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