US1595870A - Electric vacuum-tube device and the like - Google Patents

Description

Aug. 10 1926. 1,595,870 E. Y. ROBINSON ELECTRIC VACU UM TUBE DEVICE AND THE LIKE Filed March 2 1924 3 SheeFs-Sheat 1 Q I 7107' 23 z'zza Aug. 10 1926. 1,595,870

E. Y. ROBINSON ELECTRICVACUUM TUBE DEVICE AND THE LIKE Filed March 1924 3 Sheets-Sheet 5 Patented Aug. 10,1926.

' UNITED STATES PAT NT OFFICE.

,- EBNE ST ROBINSON, OF CHESTER, ENGLAND, ASSIGNOB TO METROPOLI- TAN-VICKERS ELEGTRIGAL COMPANY LIMITED, 0]? LONDON, ENGLAND, A

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BRITISH ntnc'rnro vacuum-rune DEVICE sun was: mm.

. Application flied March 29, 1923, serial Eoi 702,907, and in England April 27,1923.

This invention relates to vacuum electric devices such .asthermionic valves, and the like and more especially to such devices which are cooled during operation by means of fluid circulation, the invention being also applicable to valve devices which are continuously exhausted during operation by means of a vacuum pump such as a mercury vapour pump which is fluid cooled. In such devices it is essential that the supply of cooling fluid such as water should not tail 'since' in the one case the, part of the valve which is being cooled such as the anode would be overheated, and in the other casethe vacuum would fail.

An object of the present invention isNto provide means responsive to the condition of the supply .of'cooling fluid for protecting the vacuum tube or valve device against operation under undesirable conditions of said supply.

' of the invention is to provide protective means which upon the occurrence of undesirable condltions of the normal fluid supply effect the connection to the'tube valve or -*,pump of a supply of cooling fluid from a to valves in which the anode is operated reserve or stand-by source. In addition the protective means may effect the operation of a-wa-rning device such as a signal light or bell. Furthermore, protectivemeans may be provided for stoppingthe operatign of t e valves, such as by cutting offvthe'anode -o the cathode supply, in case undesirable conditions in the auxiliary supply should.

: also arise.

The invention is particularly applicable as-described. in the specification of my copending'application, Serial No. 699,185, filed March 1 1924, in which case itjs not neces- .sary to employ means to provide an insulatconstructed vof insulating materi 9. ta ged to be o'10ng .f lat ing column of cooling liquid between the source of the cooling liquld and the valve, It may, however, be applied to valves-in which the anode is not operatedat; earth potential, either by arrangingl that the cool-I .ing liquid is one having a ig insulation resistance, suchfor efzamgple. as pll, or else when water is en'ip oye especially'jwater which is taken a water main it'niay be arranged that the inletand outle 1 parts, particula More specifically, the object v tial are supplied with current froihaudirect Y resistance column of wateris interposed between the anode and earth. This is of course a well known arrangement which has frequently been used to insulate water-cooled from earth.

Toenable the invention to be clearly une derstood it wi now loe'described withreferenceto the ace mpanying drawings in which rly of vacuum tube devices,

Fig. v1 is a diagrammatic representation of a vacuum tube protective system in accordance with the invention, Figs. 2 and 3 are sectional elevations of two forms of pressure relay, Fig.- 4 is a sectional elevation of a cooling jacket with a thermal relay, Fig. 5 is a sectional elevation or" another iorm of pressurerelay, and Fig. 6 is a diagrammatic representation of arrangements giving further-protection in case the auxiliary sup' plyshould also fail.

Referring first to Fig. 1, this illustrates an application of the invention to a threephase half-wave rectifier, the valves 1 being of the type wherein a portion of the envelope is formed of metal, which portion constitutes the anode 2 which duringoperation is fluid-cooled. For this purpose it 'is placed in a jacket 3 through which water or othervcooling fluid from a supply main 93,

' for example, is passed by means of inlet and fectively insulated from earth. 9 The cathodes which. operate-substantially at earth-potencurrent generator 87through a switch 88 and a rheostat 89, the cathodes in this instance beingof the type which are heated by the passage therethrough of an: electric current." The anodes are. supplied with three-phase alternating current from a'starconnected secondary winding of a trans-'- former 86 the, primary of which isjonnected. with a three-phase supply. The valves 1- supply rectified alternating current to't he output circuit 90. 'Between thesupply main 93 and thecooling system'there is provided a manually o erable valve 94am an elecg trically opera 'le' valve 95; the control of;

.which latter "will behereinafter described.

' 'f'The outlet water from-the valves p to receive energy from a battery or other. a

when the flow of cooling fluid is normal.

through pressure relays 96 which may assume any ofthe forms hereinafter described 1 and Which are connected electrically in series of which is adapted to cooperate with two pairs of contacts. When coil 99 of the relay 98 is energized the upper pair of contacts is bridged by the armature whereby a coil 100 and a second coil 101 in series connection therewith are energized from a suitable source of current 102. The second coil 101 controls the operation of a valve 103, provided in a pipe connection between an auxiliary supply of Water 104 and the inlet pipes 91. The normal condition of the relay 98 when the Water cooling is adequate is with the coil 99. energized and the upper contacts thereof closed. Under these circumstances the electrically operated valve 95 is open by reason of the energization of the coil 100 and the auxiliary valve 103 is closed by energization of its operat-- ing coil 101. The lower contacts of the relay 98 control the operation of a signalling device such as an electric bell 105 adapted source 106.

With'the system above described suppos-' ing that durin the rectifying operation the water supply rom the main 93 should fail or fall below a predetermined minimum, such that the electric circuit through one or moreof the'pfessure relays 96 is broken,

' the armature of the relay 98 will fall. so that the valve operating coils 100 and 101 will be de-energized whilst the circuit of the electric bell 105 is closed to provide an audible signal. The de-energization of the coils 100 and 101 will efiect the closure of the valve 95 and the opening of the valve v103 and in this manner the main supply of cooling fluid is cutoff and the auxiliary supply 104 brought into' operation. To obtain a suitable pressgre head for-the operation of the relays 96, constrictions 108 may be provided between the said relays and the discharge pipe 107. c

When the valves are continuousl evacuated during operation by means 0 a Water cooled pump such for example as a pump of the Langmuintype similar means may be provided for protecting the system against failure of the supply. of cooling fluid to the pumps. The relays of such additional pro tective systems may be connected electrically in series with the relays ofthe system illustrated in Fig. 6. Furtnermore when the valve is continuously evacuated during operation failure of the water supply will result in an increase in temperature of the anode which in turn will cause gas to be given off therefrom and render the valve soft, as an alternative type of relay a gas pressure gauge may be connected with thevalve and arranged to operate a relay. For example an ionization gauge maybe employed which when the gas pressure in the Valve rises above a predetermined maximum will operate a protective relay. Such ionization gauge may be connected Wth the interior of the valve and the circuits of the gauge may be so arranged that when the positive ionic. current collected by the electrodes exceeds a predetermined amount, the relay is tripped and the necessary protection eifected.- Alternatively, a relay of the thermostat type may be employed that will be hereinafter described. 7

Referring to Fig. 2 which illustrates one form of the relay 96 in detail, the U-tube 30 is formed of glass and partially filled with mercury and is connected to a T-branch 31 of the outlet pipe'92 by means of a rubber sleeve 32 or otherwise. The tube 30 is provided with bulbs or enlargements 33 and 34 for a purpose to be hereinafter explained. One of the gontact electrodes 35 .is inserted in thelower part of the U-tube whilst the other contact electrode. 36 is inserted therein at a higher level which depends upon the pressure in the portion 20 of the outlet pipe tion with Fig. 2 but the U-tube 40 is of metal such for example as steel whereby a more robust construction is obtained. The upper end of the U-tube 40 is enlarged at 41. The other end thereof is secured to a plug 42 which is in turn secured within the end of a reservoir 43'which is connected to the T-connection 44 of the outlet pipe by means of a union 45. The reservoir 43 is provided with a plug 46 .by means of which the mercury may be introduced into the tube. The enlarged portion 41 of the U-tube 40 is secured to the base of the second reservoir 47 the upper end of which is provided with a cap 48 which supports a metal bush nut 49 insulated from the cap 48 by means of bushes and washers 50 of insulating material. A screw-threaded metal rod 51 passes through the bush 49 and is provided with external terminal nuts as shown. The metal tube 40 constitutes one electrode of the'device whilst the rod 51 constitutes the other electrode. The rod 51 may be spaced from the metal tube 40 by means of a fibre Washer 52 which the bush 49.

" portion 41 of the tube.

rubber ring which is clamped between the .end of the jacket 3 and a cap-ring 56 which has screw threaded engagement with the jacket 3. The water entering by the in let pi e 4: and leaving b the pipe 5 is given a big velocity throug the jacket by the provision-therein of an annular member 57 Electricalconnection between the anode 2 and jacket 3 is- -provided by means of the flexible member 58. A glass tube 59 having a bulb 60 at one end 1s inserted through aligned openings in the jacket 3 and member 57 so that the bulb projects into the path of the cooling fluid passing through the -jacket.' The tube-59 c0nta-ins a body of mercury'and is provided with a contact 61 which .is always immersed in the mercury and. a second contact 62 which becomes immersed in the mercury when the. latter rises within the normally unfilled portion of the tube 59.

due to the heat in the jacket 3 after the manneroth thermometer. The upper electrode 3 62 is so located within the tube that when the temperature of the bulb 66'exceeds a predetermined limit the contacts 61 and 62 which are connected with the protective gear as described in connectirgn with Fig. 1 are connected, together by the mercury. In this case, however, the contacts on the relay controlled by the coil 99 willbe altered so that they are normally closed instead of being normally opened as illustrated in Fig. 1. -.-'lhe thermal device is preferably removably mounted in the jacket and to this end it is v secured in a metal sleeve 64 having a conical nectedto'the supply pipe of t e water jacket of thewalveor the diffusion pump asthecase may be by means of the perforatedcap 7-1 and the union 72-. A n accurately fitting piston '73 operates wi'thiirthe cylinder 70 such piston preferabl% ifiange 65'where'by itmay be securedin pos tion by the flange nut or union 66.. The vertical portion of the tube is protectedagainst damaged-lid mechanical shock by means of. a metal cover which is constructed in twoii parts 67 and .68 as shown, the latter of which? parts is soldered or otherwise;- permanently connected with the metal :tube 64 whilst the portion 67 is tubular and arranged to vfit upon and around the portion68.v The con-:

ductors connected with the electrodes 61 and 62 pass through a gland 69.

' Ehe modified form .of p'ressure rela illus-j trated in Fig. 5 comprisesa linden 0 conhaving: a on leather as indicated rat-17 t, -he gp nrg iss e:

nectedwith. a pivoted 7 5 through a v or other parallel motion 76. The arm 7 5 carries a relay contact member 77 which cooperates with a second contact member 78 mounted upon but insulated from a bracket 79 which may be secured to the cylinder 70.

The contacts are normally retained separated by means-of a spring 80. In operation the water pressure acting on the underside of the piston 70 tends to close the contacts 77 and 78, thus controllingthe protective gear in a manner similar to that previously described In the event of the water pressure ,fallingbelow a. predetermined minimum the contacts open whereby the anode and cathode currents may be cut 0d or alternatively a reserve or stand-by source of cooling water connected to the jacket. The contants 77 and 78 may control the operation of the contactor switch 26 directly "that is to say, the intermediate relay 21 of Fig. 1 may be omitted.

Referring now to Fig. 6, which illustrates how protection against the operation of a valve may beprovid'ed in case the auxiliary supply also fails, the valve lis of the three electrode type and the anode is operated at earth potential in the manner described in the specification of my co-pending'application, Serial No. 699,185, tiled'll/ larch 1a, 192%, and the valve is arr-tugged to generate oscillations. in a circuit-sue as the antenna 6. Power is supplled to the valve by means tive terminal of which is connected to the anode 2 and also to earth. Asshown, the

generator 7 may be connected to the water .'acket 3 to which the anode 2 is connected y means of a flexible or resilient conductor.

of the direct current generator 7 the posi- 8.. The anode current passes through the? anode coil 9 which is coupled to the antenna coil'andjthence passes to the cathode ct the valve. .The grid coupling coil is indicated."

at 10. In the present instancethe valve 1 has-a cathode of the type described in the specification'of my copending applicat on,- Seria'i'No. 653,544,; ifiled 24th July, 192:} a and eon'sistsof two' metallic tubes mounted onewithin the other of which the inner tube'is at negative otentiaLwith respect to the outer tube so t at heating space current flows from theinner tube to the outer tube. The cathode isbrought unto the tem rature at which it-will maintain itself due- 4 the space ciirrent between its per tions by means ofan auxiliary filament cathode whichfis mounted within the inner '1 tube. In Fig.1 the conductors 1.1 supplyi current to" the auxiliary filament cathode and'theconductors 12 are connected to the aforesaid tubular portion of the cathode. The, heating space current is supplied by 12. g The current for; the filament the generator 13 whichis connectedthrough p a the variable resistance 14jtothe conductors cathode is supplied from the gendrator 13 through a fixed resistance 15 and a variable resistance 16 in series therewith.

The outlet pipe 92 from the water jacket 3 has connected to it a pressure relay 96 which may be in the form of a U-tube con- .tamlng a body of mercury as illustrated in Figs. 2 and 8. Said tube is provided with two electrodes 18 and 19 which areso arranged that when the cooling fluid is flowing the mercury establishes connection between them owing to the pressure head in the portion 107 of the pipe which is remote from the relay 96 and jacket 3. When the electrodes 18 and 19 are thus connected together by the body of mercury the relay coil 99 is energizdd from a suitable source of current such as a battery 97 and the-energization of the coil 99 operates a contact member 23 to bridge the relay contacts 24 thereby effecting the energization of the operating coil 25 of a contactor. switch 26 h from a suitable source of current 102. The energization of the coil 25 causes the contactor switch 26 to close and complete the circuit by which a heating current is supplied to the cathode of the valve 1, this circuit passing through a manually operated switch 28 the function of which will be hereinafter described. With this arrangement it will be observed that unless a predetermined pressure obtains within the portion 20 of the outlet pipe the contactor switclr26 will open after a time interval, whereupon the supply of current to the valve is cut 'ofi. Furthermore, in the event of the supply of water falling below a predetermined amount the pressure will fall and the 'contactor switch will be opened as above described so that both the anode current and cathode current are automatically cut ofl.

In order to start the operation of the cathode the switch 28 is pressed downwards whereby 'the auxiliary cathode is supplied with heating current and at the same time the inner "tube of the cathode is made positive with respect to the auxiliary cathode. The resistances 15 and'16 provide such a voltage drop as to make the inner tube sufficiently positive with respect to the auxiliary cathode. Heating current from the generator .13 passes from the auiliary cathode to the inner cathode tube which isadditionally heated by radiation-from the auxiliary cathode. When the inner cathode tube is raised to a sufficiently high temper ature the switch 28 is moved to its upward position whereby a potential difference is established between the inner and outer cathode tubes and at the same time the supply of heating current for the auxiliary cathode is cut off. The generator 7 which supplies the anode current is connected to the positive terminal of the cathode heating system. A condenser is connected across the generator 7 in order to pass the high frequency com onent of the anode current.

Whilst in t e above described arrangement the valve is provided with cathodes which are heated as described in the specification of my co-pending application, Serial No. 699,185, filed March 14, 1924, it will be understood that the cathode may assume other forms and may be heated in a ditlerent manner arid also that the source of directcurrent for the anode may be a thermionic rectifier or battery of accumulators.

Alternatively to the above described arrangement it may be arranged that on operation of the relay the anode current only is cut off or both the anode and the cathode heating currents may be cut oil by respective switching devices. When the gap between the anode and cathode is large it will generally be sufficient to interrupt the anode Ell current only but when the gap is relatively the electrical circuit is made instead of broken, in which case said relays will be connected in parallel with one another, with the battery or source of current and with the operating coil of the water valve controlling relay.

' I claim as my invention:

1. In an electrical system, the combination with a vacuum electric tube device having a part thereof which is adapted to be fluid cooled during operation, and a supply of cooling fluid therefor, of an auxiliary supply of cooling fluid, and means which be come operative to connect said auxiliary supply to the system when the condition of the first-mentioned supply of cooling fluid becomes undesirable.

2. In an electrical system, the combination With a vacuum electric tube device having a part thereof which is adapted to be fluid cooled during operation, and a supply of cooling fluid therefor, of an auxiliary supply of cooling fluid, and a fluid pressure operated relay adapted to connect said auxiliary supply to the system when'the fluid pressure of the latter falls below a predetermined value.

3. In an electrical system, the combination with a vacuum electric tube, device havin a part thereof which is adapted to be fluid cooled during the operation, and a supply of cooling fluid therefor, of an auxiliary supply of cooling fluid, and a relay controlle by weaero the discharge pressure of the cooling fluid to control the connection of said auxiliary ply of cooling fluid, and means which become operative to connect said auxiliary supply to the system when the condition of the first-mentioned supply of cooling fluid becomes undesirable, and means for protecting the system against operation when the condition of the supply of cooling fluid is undesirable.

5. In an electrical system the combination with a vacuum electric tube device having an anode thereof which is maintained at earth potential and is adapted to be fluidcooled during operation, and a supply of cooling fluid therefor, of an auxiliary supply of cooling fluid, and means which becomes operative to connect said auxiliary supply to the system when the condition of the main supply becomes undesirable.

6. In an electrical system, the combination with a plurality of vacuum electric tube devices having parts thereof which are adapted to be fluid cooled during operation, and a supply of cooling fluid therefor, of an auxiliary supply of cooling fluid, and a vplurality of relays responsive to fluid pressure in the system for connectin said auxiliary supply when the conditions m the firstmentioned supply become undesirable, said relays being connected electrically in series.

In testimony whereof I have hereunto subscribed my name this 18th day of March, 1924.

ERNEST YEOMAN ROBINSON,

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