US2457948A - Electron discharge device - Google Patents

Description

Jan. 4, 1949. A. G. THOMAS ELECTRON DISCHARGE DEVICE Filed Feb. 16, 1945 FIGZ FIG. I

FIG.3 F|G.4-

HVVENT0R.

Patented Jan. 4, 1949 UNITED STATES PATENT OFFICE 2,457,948 ELECTRON DISCHARGE DEVICE Albert G. Thomas, Lynchburg, Va.

Application February 16', 1945, Serial No. 578,244 g Another object is to provide an electronic relay in which a principal pool cathode type relay is combined with the controlling electronic tube.

A further object is the provision of an electronic relay for large currents combined with a control electronic tube or relay for relatively small currents, in one envelope.

An additional object is to provide an electronic relay for large currents combined with an electronic control relay for smaller currents so that the smaller relay is efiectively cut out of circuit automatically when the larger relay conducts appreciable current.

Another object is the provision of an electronic relay combined with a control tube which automatically determines thefiring point of the voltage cycle.

Other objects will appear in the following description:

In the drawings:

Figure 1 is a part sectional elevation of an electronic relay with pool type cathode combined in the same envelope with a gaseous or other electronic control relay or tube.

Figure 2 is a part sectional elevation of a device similar to that shown in Figure 1 but with in-built means for effectively removing the control relay from the circuit when the pool cathode relay conducts suflicient current.

Figure 3 is a part sectional elevation of a combination pool cathode relay and hot filament relay, the filament being in series with the line.

Figure 4 is a part sectional elevation of an electronic relay or tube shown connected in a circuit. The filament of this tube is connected in series with the anode voltage source.

In Figure 1, envelope I' of glass or othersuitable material has sealed cross partition 2 of similar material forming chambers A and B Chamber A has anode 3 of any well known construction such as of nickel, and filament cathode 4 and grid 3 are provided. Suitable leads from the anode and grid are sealed in envelope I in known manner and the leads 8--9- to cathode 4 are: preferably sealed in partition land are brought out of the envelope as shown sothat;

9 Claims. (Cl. 250-275) rent source H) which may 6 to cathodel which may element 4a adapted to to battery or other curbe the secondary of they may be connected a transformer.

Rod 6' which may be of graphite or other suitable material, is supported by connected lead II, or in any other manner. Lead ll connects rod have connected heater emit electrons freely. Element 4a is preferably coated with barium oxide or other suitable material of relatively low work function. If desired, hot wire cathode 4 h alone may be used.

Rod 6 clips into cathode pool l2 of mercury or suitable material and preferably nickel or graphite anode I 3 is fastened in chamber B to lead l4 sealed in envelope l. Other means of support such as glass stems could be used.

Electrically conducting plate I of suitable material such as metals or the like, is placed in contactwith pool l2 and is connected with lead l5 sealed in envelope I. The device is preferably positioned vertically as indicated.

Anodes 3- and I3 are connected to line conductor IB- and lead [5 from cathode l2 for chamber'B is connected to line I! through load L which may be a motor or any other current operated device.

Grid 5 is connected with terminal l8 and terminal' [9- is connected with cathode 4--4a.

Rod 6 may be composed of graphite or of material which changes its resistance markedly withvariation of current passing through the material. Various compounds or mixtures of silicon carbide, carbon, zinc oxide, boron or the like, have such characteristics. If rod 6 is made of a suitable material of this type it will normally oifer a relatively high resistance which can be greatly reduced to facilitate forming an are when current is passed through the rod tomercury or other material I 2.

Rod 6 may also consist of graphite mixed with carborund-um crystals, silica, or other finely divided or cystalline particles in order to facilitate the forming of spots of highpotential gradient. If desired, therod may comprise a metal rod coated'with graphite or other material for better conductivity through the graphite. A smaller unit can be made in this way. Semi conducting material'such as selenium, copper oxide, aluminum oxide or the equivalent may also be effective as means for producing a high potential gradient between the rod and the cathode material l2.

ber B from anode cury pool l2, for instance, will then become that relatively heavy current passes ionized so from line 16 through anode l3 and chamber B to cathode I2 and so through load L. 3

If pulsating direct current is applied in lines it and H or alternating current, then grid 6-pool l2 junction may be made negative to stop the current flowin chamber B when the potential difference between lines l6 and l! falls below a critical value.

Chamber A preferably contains gas such as argon, or argon and mercury in order to' provide sufficient current flow. This chamber may be placed to the side of chamber B, within that chamber, or below it as desired.

This combined heavy duty electronic valve and relatively small current control valve is much more convenient to use than prior devices which haveto be assembled in various groups. 7

Envelope I may be of metal which may have cooling fins if desired. Conductors l5 and 16 would be suitably insulated from the metal envelope.

In Figure 2 the construction is the same as in Figure 1, as indicated by like numerals, except that in this modification grid 5 is connected to cathode 4-4a. through resistor or impedance element when the grid circuit is closed by connecting a source of potential between terminals l8-l9. This source can be a battery, generator, a current-carrying resistor, or a condenser or inductance which could also be wound to have considerable reactance. Anode I3 is connected-to the grid-connected end of resistor 20 the other end of which is connected to line 16 as well as to cathode 4-4a.

By means of the above described arrangement chamber A conducts current to rod 6 until current conduction between anode l3 and cathode i2 occurs at which time the current passing through resistor 20 from line l6 causes a poten: tial drop in resistor2fl which biases grid 5 negatively with respect to cathode 44a' so that cur rent conduction from anode 3 to that cathode is stopped or reduced when current is passed from anode l3 to cathode l2. In this way the-starting.

relay is automatically cut out of circuit or increased in efiective resistance when the power or larger relay passes current.

In case sufficient gas is contained in chamber A, then alternating current orpulsating direct current potential should be applied between posi tive line 16 and negative line H. Resistor 20 can be of suficiently high value so that it will cut off current fiow in chamber A at a relatively low value of current in chamber B. The resistor is preferably sealed in the envelope l but may be placed outside if desired, or in any other.

suitable location.

This form of the invention may be changed. from a non-conducting to conducting state by increasing the voltage betweenlines l6 and 11 if terminals I8 and I9 are connected or by connecting these terminals together directly or through a potential source which biases grid 5' positively with respect to cathode 4-4a, if necconductor2l is same numerals as before.

4 essary. The negative potential drop across resistor 20 can then be sufficient to overcome the positive bias.

An advantage of this modification is that the starting relay is cut on and off by one operation instead of by two as before, if the relay in chamber A is normally non-conducting. By varying the bias of grid ,5 or the value of resistor 20'the pointinthe line cycle at which cut off in chamber B occurs can be regulated.

" In Figure 3, like parts are designated by the In this form of the invention line 16 is connected to anode .3, as be fore,.but cathode filament 4 is connected in series with lines It and I! by means of conductors 25,

22, and .23 wholly or partially sealed in envelope 1., Conductor 22 is connected to line ll on the line side of load L the other terminal of which is connected to cathode plate or other element l.

Resistor 23a is preferably connected in series with conductors 2|, 22, cathode 4, and conductor 22. .If this resistor is used then lead 24 from brought out as shown and connects with tenninal25 which may be connected to the positive: terminal of biasingbattery'Zfi the negativeterminal of which maybe connected to ter minal .2'L' Conductor I4 is connected with con- I ductor 23 or filament 41as indicated. A switch 29 can be provided for opening and closing the filament circuit. 1 I

In operation, if switch 29 is closed and line it is connected to. anode-3 and line H is. connected I to the junction of conductor 22 and conductor 28 irom load-L, thencurrent will pass through resistor 23a and filament 4 to heat that cathode.

Nil appreciable current will pass through chamber B and-load L however if grid 51s biased sufiicient- H ly negatively withrespect to cathode 4-4a. Grid I 5 may be'biased'by a' L that-mercuryvapor in chamber B will become cathode l2, load L and conductor 28.

I potential source suitably connected between terminals [8 and 69. If then, grid 5. is fmade positive or sufficiently less negative,'current will pass from anode 3 to cathode 4- 4aand through rod 5 to produce electrons so ionized landcurrent conduction from line it to line 11 will'take place through conductor 2i, resistor 23a, conductor 14, anode l3, chamberB,

' If fluctuating or alternating potential occurs between linesl6 and ll then current flow through chamber B and load L can be stopped by making grid 5 sufficiently negative with respect to cathode 4-40 so that the starting current in chamber A r willbe prevented bya relatively low anode potentialpoint. Another terminal 18 to terminal 2'1 as indicated. Then grid 5 is normally negatively biased by battery orother potentialsource 26,50 that there is no appreciable current conduction in chambers A and B. when the potential betweenlines l6 and I1 is below a predetermined valuea At some point in the cycle, however, this potential will rise to the critical value so that sufiicient current flows through resistor 23a to. bias grid 5 positively or sufiicientlyless negatively with respect to cathode 4--4a to allow current conduction in chamber A from anode 3 to cathode 4-41: with the result that current conduction in chamber B and through load Loccurs. The point in the line potetial cycle'at which current conduction through chamber B and loadL occurs can then be regulated by varying the potential of source 26 or by varying the value of resistance 23a which may be tapped or placedoutside envelope I. In this way mode of operation is to connect grid.

the average magnitude of current through load L can be varied.

This modification is very useful and convenient since it can be connected directly in the line, only a few connections being necessary. This device is therefore much simpler to use than prior gaseous relays which require numerous connections and circuits. It will be observed that no current passes through the load until chamber B conducts, but if the current through filament 4 is not objectionable, conductor 22 can be connected on the opposite side of load L.

The bias of grid 5 can be adjusted to compensate for the potential drop across resistor 23a, due to normal filament drain. The current through this resistor is increased when chamber B is fired.

Resistor 22a is placed in series with conductor 22 to insure a potential difierence between anode I3 and cathode l2.

A circuit showing a relay tube similar to the upper relay of Figure 3 is illustrated in Figure 4. The filament 4 can be supplied with current from anode potential source 39 through both the load L and line 32 if switch 3| is closed and through load L if the switch is open. The resistance of cathode filament 4 or its connected lead may be sufiicient to keep the initial current flow through the load to relatively low values, if load L requires considerable current in proportion to that supplied to the filament. Load L will then receive its full current when grid 5 is of proper polarity and potential.

Various other modifications can be readily made without departing from the general principles I have disclosed.

What I claim is:

1. In an electron discharge tube, means forming two chambers, a first cathode, a grid, and a first anode in one said chamber; a pool type cathode, a second anode, and a control element in the other said chamber; an impedance element connecting said first anode and one terminal of said first cathode, and another impedance element connecting the other terminal of said first cathode and said pool type cathode.

2. In an electron discharge tube, means forming two chambers, a first cathode, a grid, and a first anode in one said chamber; a pool type cathode, a second anode, and a control element in the other said chamber; an impedance element connecting said first anode and one terminal of said first cathode, another impedance element connecting the other terminal of said first cathode and said pool type cathode, said grid being electrically connected with said first anode.

3. In an electron discharge tube, means forming two chambers, a first cathode, a grid, and a first anode in one said chamber, a pool type cathode, a. second anode, and a control element in the other said chamber; an impedance element connecting said first anode and one terminal of said first cathode, another impedance element connecting the other terminal of said first cathode and said pool type cathode, and a source of potential connecting said grid and said first anode.

4. In an electron discharge tube, means forming two chambers, a first cathode, a grid, and a first anode in one said chamber; a pool type cathode, a second anode, and a control element in the other said chamber; an impedance element connecting said first anode to one of the terminals of said first cathode, another impedance element connecting the other terminal of said first cathode and said pool type cathode, means connecting said grid and said first anode, and means connecting said control element and said first cathode.

5. In an electron discharge tube, means forming two chambers, a first cathode, a grid, and a first anode in one said chamber; a pool type cathode, a second anode, and a control element in the other said chamber; an impedance element connecting said first anode and one terminal of said first cathode, another impedance element connecting the other terminal of said first cathode and said pool type cathode, and means connecting said second anode and said control element to said first cathode.

6. In an electron discharge tube, means forming two chambers, a first cathode, a grid, and a first anode in one said chamber; a pool type cathode, a second anode, and a control element in the other said chamber; an impedance element connecting said first anode and one terminal of said first cathode, another impedance element connecting the other terminal of said cathode and said pool type cathode, means connecting said second anode and said control element to said first cathode, and means connecting said grid with said first anode.

7. In an electron discharge tube system, a cathode having a pair of terminals for supplying heating current to said cathode, an anode, a grid, an impedance element connecting said anode and one terminal of said cathode, the other terminal of said cathode being connected with the negative terminal of a. source of current, and said anode being connected with the positive terminal of said source for passing current from said source through said impedance element and said cathode in series.

8. In an electron discharge tube, means forming two chambers, a first cathode, a grid, and a' first anode in one said chamber; a pool type cathode, a second anode, and a control element in the other said chamber; an impedance element connected in circuit with at least one of said anodes, and means connecting said grid with said impedance element to cause biasing of said grid as a result of current fiow through said impedance element.

9. In an electron discharge tube, an anode and a positive terminal connected thereto, a thermionic cathode and a negative terminal connected thereto, an impedance element connected in series with said cathode between said terminals, and grid means for controlling electron flow between said cathode and said anode.

ALBERT G. THOMAS.

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

UNITED STATES PATENTS Number Name Date 887,642 Jackson May 12, I908 1,976,391 Foster Oct. 9, 1934 2,071,057 Baruch Feb. 16, 1937 2,113,392 Baruch Apr. 5, 1938 2,117,246 Haglund May 10, 1938 2,220,077 Cofiin Nov. 5, 1940 2,235,504 Rennie Mar. 18, 1941 2,263,171 Hays Nov. 18, 1941 2,314,691 Dawson Mar. 23, 1943 2,322,754 Undy June 20, 1943 2,369,767 Abernathy Feb. 20, 1945

Images