US2428000A - Baffle arrangement for vapor electric devices - Google Patents

Description

Sept. 23,1947. H. WINOGRAD BAFFLE ARRANGEMENT FOR vA roR ELECTRIC DEVICES Filed Aug. 16, 1946' INVENTOR lumna/bad a Win 15v A ORNEY Patented Sept. 23,1947

BAFFLE ARRANGE ELEOTRI OFFICE MENT ron varoa c navrcas Harold Winograd, Milwaukee, Wis., assignor to Allis-Chalmers Manut waukee, Wls., a corpor acturing Company, Milation of Delaware Application August 16, 1946, Serial No. 690,861 Claims. (Cl. 250--27.5)

This invention relates in general to improvements in vapor-electric devices and particularly 1 to means for controlling the paths of the arc discharge and of the flow of vaporized cathode material in arcing devices of the liquid cathode type.

Vapor electric devices of the liquid cathode type are generally provided with bafiles for controlling' the paths of the arc discharge and of the flow of vaporized cathode material to thereby control the density and the rate of deionization of the vapor within the path of the discharge. Some of the baiiling means may be so disposed as to define a sinuous path for the discharge.

Other bailiing means arranged outside the path of the discharge to guide the discharge away from the casing wall may be fluid cooled to also perform the function of vapor condensing means. A portion of such vapor condensing means may be made pervious to the outward flow of vaporized cathode material to render the outer surfaces of the condensing means available for condensation.

\ The portion of the vapor condensing baiile means cooperating with other bailies to conflne the anode and any control electrode associated therewith is preferably made impervious to the inward flow of cathode material and to outward heat radiation from the anode and control electrodes. As a result of such arrangement, heat radiated from the anode and control electrodes does not interfere with the condensation of Vaporized cathode material and at the same time the vapor density within the space adjacent the anode and control electrodes may be maintained at a minimum value. When the path of the discharge is rendered sinuous by means including an annular battle, it is advantageous to dispose a conductor within the annular batlle to render annular the path of the discharge and thereby accelerate the rate of deionization of the vapor within the baiile.

It is therefore an object of the present inven-.

tion to provide an improved baiile arrangement for vapor electric devices whereby surfaces for condensing vaporized cathode material are shielded against the action of the discharge and against heat radiation from elements of the device operating at high temperatures.

Another object of the present invention is to provide an improved baille arrangement for vapor electric devices whereby the vapor density within the spaces adjacent the anode and any control electrode may be maintained at a relatively low value.

2 I, provide an improved baille arrangement for vapor electric devices whereby the rate of deionization of the path of the discharge may be raised to a relatively high value.

Objects and advantages other than those above set forth will be apparent from a consideration of the following description when read in connection with the accompanying drawing which shows a view in vertical cross section through a vapor electric device provided with a fluid cooled coil ballle cooperating with transverse. bafiles to hinder the access of vaporizedcath'ode material to the space adjacent the anode andIc'ontrol electrodes.

Referring more particularly to'the drawing by characters of reference, the vapor electric device illustrated therein comprises a flanged cylindrical casing 6 which is assumed to be made of conductive material such as steel, but it will be understood that the invention may also be embodied in devices provided with casings of insulatin material. Casing 6 is associated with a disc-shaped steel cover 1 sealed thereagainst by means of a gasket 8 of suitable material such as rubber. Gasket 8 is maintained under pressure by the screws (not shown) fastening the cover to the casing and maintaining the ,cover and the casing in electrically conductive connection. Cover 7 carries a single main anode 9 supported thereon in gas-tight insulated relation by any suitable known For example, flanged bore 5 and is adapted to form a seat for a two-part The insulator is sealed against seal i2. The conductor I3 carrying the current to anode 9 extends through insulator i l and is sealed thereagainst by suitable means such as a blind sleeve l4 associated with a mercury seal it. Conductor i3 is screwed into the tapped bore of sleeve l which may be provided with a radiator I5.

Another object of the present invention is to Anode 9 may be made with the generally cylindrlcal contour shown in the drawing, and may consist of any suitable conductive material such as graphite. The anode may be divided into two parts assembled by screw threads, the upper anode portion being clamped against insulator II by a spring l1.

The cathode l8 of the device preferably consists of a pool of mercury or other suitable vaporizableconductive material disposed in the bottom ofcasing 6 in conductive relation thereto, or disposed in a cathode well insulated from the ,Grlds l9, 2| may be made M I as graphite, and grid I9 is forations which are .of .heat from the cylindrical :suniace of anode 9.

.porized from the of a metal gutter 35 bly are not made fluid to heat radiation from casing. Anode 5 and cathode 5:81am preferably disposed in axial alignment in basing 6.

Control electrodes I9, 2| of the grid type may be arranged in proximity to anode 9 to control the flow of current between anode and cathode.

any suitable conductive material such preferably made basket moped to follow the contour of anode 9. The flat bottom wall 22 of grid is is provided with cylindrical or coaxial annular apertures for the passage of the arc discharge between anode 8 and cathode l8. The cylindrical side wall 23 of grid B may be provided with perpermeable to the radiation Grid I! may be supported in any suitable manner and may be impressed with control potentials through a. connection 2 4 penetrating cover 1 in insulated and gas-tight relation thereto. Grid 2| may be disc-shaped. provided with cylindrical or coaxial annular apertures and may be impressed with control potential through a consection 25 similar to connection 24.

The paths of the arc discharge between anode 8 and cathode l8 and of the flow of material vacathode, are controlled by means of a plurality of bailles including a flat annular baille 26, a. disc-shaped bame 21 and a fluid cooled pipecoil ballle. The coil is generally cylindrlcal in shape and comprises an upper portion 28 surrounding anode 8. grids l8, 2| and baille 26 and a lower portion 28 surrounding at least a part of the space contained between the anode and the cathode. Coils 28, built as a unitary structure comprising two helically wound pipes extending over the entire length of both coils and having their turns interleaved. At the bottom end of coil 28, the two pipes are joined by an annular header 80. At the upper end of coil 28 the two pipes are provided with upstanding extensions 8|, 32 penetrating cover 1 in gas-tight supporting relation thereto.

When the cathode is in conductive connection with the casing, it is advantageous to utilize coils 28, 28 to shield the casing against the are discharge between anode and cathode to thereby prevent accidental arcing between the anode and the casing. Coil 2a is accordingly sealed with anode l2 in arc impervious relation thereto by connecting means comprising insulator II and of a conical sheet metal shield 33. Coil 29 is likewise sealed with cathode |8 in arc impervious relation thereto by means of an annular insulator 34 and also serving to collect mercury condensed on the coil. The connections of the coils with the anode and the cathode preferatight. The designation of such connections as are impervious is intended to mean that arcing between the anode and the casing past such connections does not take place as long as the device is properly conditioned and is connected in a circuit operating under the intended conditions of voltage and current.

Whether predetermined connecting elements will be arc impervious under such conditions can only be determined by experimen and it will be understood that elements which are are impervious under the intended operating conditions may not necessarily remain arc impervious under certain abnormal operating conditions.

In at least coil 29, the pitch of the turns is so chosen that adjacent turns are separated by substantial interstices to form an element pervious the arc and pervious to the flow of material vaporized from cathode I8 mixed with gases to be evacuated. when co l 9 28 however are preferably is to shield easing 8 against arcing. the interstices between turns should be sufliciently narrow as to be impervious to arcing to the same extent as the elements sealing the coil with the anode and the cathode. The maximum permissible width of such interstices for predetermined operating conditions can only be determined experimentally.

Coil 28 is made substantially impervious both to the flow of vaporized cathode material and to heat radiated from anode 8 and grids l8, 2|. Such characteristics may be imparted to, the coil by causing adjacent-tums thereof to be in contact without forming interstices or by providing additional means for closing the interstices between turns. The turns of coil 28 are preferably wound with the same pitch as the turns of coil 28, and a suitable metallic wire 38 is applied against the surfaces of adjacent turns of coil 28 to close the interstices thereof while leaving the interstices of coil 28 open. Wire 26 may be held in place merely by its own resilience or may be fastened to coil 28 by welding or otherwise. It will be understood that coil 28 may also be replaced by a double walled fluid cooled cylinder inherently impervious to the flow of vaporized cathode material and to heat radiation.

The outside diameter of grid 2| is so chosen that the grid clears coil 28 and wire 36 with a relatively small clearance to cooperate therewith to confine a space following substantially the contour of grid l9. Grid 2| may conveniently be suspended from coil 28 through shield 33 and through a plurality of straps 81 and of insulated studs 38. Straps 81 may also support baffle 26. which is of greater diameter than grid 2| and is conductively connected with coil 28 through the straps. Baille 21 may be suspended from baflle 26 through suitable conductive studs 39.

Bafiles 26, 21 cooperate with coil 28 to confine a space following substantially the contour of grids l9, 2|. Ballle 21is of smaller diameter than baiile 26 to define therewith a sinuous path for the arc discharge between anode and cathode. Baiiles 28, 21 and grid 2| also define a generally cylindrical chamber 4| surrounded by baille 26. A member 42 of conductive material is disposed within balile 26 to render annular the portion of the arc path included in chamber 4| and thereby accelerate the deionization of the vapor contained within such chamber.

Baille 21 may support a graphite ignition-excitation anode 43 insulated therefrom and provided with an insulated connection 44.. A device 45 of any suitable known type is provided for projecting mercury from the cathode on anode 43 to ignite an are at the cathode.

The cathode may be cooled by means of a water jacket 46 connected in series with coils 28, 29 and a source of suitable cooling fluid, such as water. Casing 6 may be evacuated by means of a suitable pumping system (not shown) connected with an outlet 41 provided through the wall of easing 6 in proximity to coil 28. Cathode mercury condensed in the evacuating system and returned to casing 6 through outlet 41 may be deflected away from coil 28 by means of a baiiie 48. A coating 49 of suitable insulating material, such as vitreous enamel, may be provided on the side of baille 48 facing outlet 41 to prevent a stream of mercury from bridging casing 6 and coil 28.

The operation of the device may be initiated by establishing an are between anode 43 and cathode |8, as is well known. In general, anode 8 is required to carry periodic current impulses under the control of the potentials impressed on grids l9, 2|. Each anode current impulse is conducted by an are established between the anode and the cathode through the vapor contained within casing 6. The are passes through the apertures of grid portion 22 and of grid 2| and follows the sinuous path defined by baffles 26, 21, 29 and deionizing body 42. The flow of current raises the temperature of the elements contained in casing 8 to an extent in relation to the current intensity.

Part of the heat radiated from anode 9 is directed through the apertures of grid I9. A per-'- tion of such heat is intercepted by grid 2 i, 'baflles 26, 21 and deionizing body 42. Theheat radiated by anode 9 through the apertures of wall 23, with part of the heat radiated by the grids and by ballie 26, is intercepted by cOil 28 and removed by the flow of cooling fluid therethrough. Coil 28 likewise serves for the removal of heat radiated thereto by the arc and by the elements of the device operating at elevated temperature. Some heat is also radiated through the interstices of coil 29 to be transmitted to the ambient atmosphere through casing 6.

As a result of the arrangement of bailies 26, 21, 2B, 29, material vaporized from cathode l8 partly condenses on the surfaces of coil 29 facing inwardly. Part of the vapor passes through the interstices defined by the turns of coil 29 and condenses on the surfaces of coils 28, 29 facing the wall of easing 6. During extended operation of the device, the surfaces of coil 28 facing anode 9 are however brought to such temperature by radiation of heat thereto so that mercury vapor cannot condense thereon. There is accordingly no appreciable flow of vaporized mercury within the space confined by baiiles 25, 21, 28 about anode 9 and grids l9, 2|. As a result thereof, and of the high temperatures of the anode and grids, the vapor density within such pace is relatively low.

The space in question is also reduced to a minimum in size by the arrangement of the bafiies and of the deionizing body 42. The maximum distance that ionized vapor particles contained within such space must travel to encounter deionizing surfaces is further reduced becauseichamber 4| is rendered annular by the provision of deionizing body 42. The time required for deionizing the vapor in the space adjacent the anode and .the grids-after each operating period of the anode is thus considerably shortened, and the rate at which the anode potential varies after each operating period may be increased to a corresponding extent.

As a result of the presence of wire 36 between turns of coils 28, heat radiated from anode 9 is unable to revaporize any of the mercury condensed on the outer surfaces of coil 28. Mercury dripping along the outer surfaces of coil 28 is also prevented from entering the space surrounded by the coil, in which the vapor density should be maintained at a relatively low value. The effectiveness of coil 28 as bailles means, radiated heat removing means and vapor condensing means, is however in n'owise adversely affected by the presence of wire 36.

Although but one embodiment of the present invention has been illustrated and described, it will be apparent to one skilled in the art that various changes and modifications may without departing from the spirit of the invention be made therein ated casing, an anode and a, pool of vaporizable conductive material serving as a cathode in said casing, and means for controlling the vapor density within said casing comprising a fluid cooled element impervious to the flow of material vaporized from said cathode pool surrounding at least said anode and a fluid cooled element pervious to the fiow of material vaporized from said cathode pool surrounding at least a portion of the space contained between said anode and said cathode pool.

'2. A vapor electric device comprising an evacuated casing, an anode and a pool of vaporizable conductive material serving as a cathode in said casing, and means for controlling the vapor density within said casing comprising a fluid cooled element impervious to heat radiation surrounding at least said anode and a fluid cooled element pervious to heat radiation surrounding at least a. portion of the space contained between said anode and said cathode pool.

3. A vapor electric device comprising an evacuated casing, an anode and a pool of vaporizable conductive material serving as a cathode in said casing, and means for controlling the vapor density within said casing comprising a fluid cooled coil having a first portion surrounding at least said anode at least a portion of the space contained between said anode and said cathode pool, said first coil portion being impervious to the flow of material vaporized from said cathode pool and said second coil portion consisting of spaced turns defining interstices pervious to the flow of vaporized material from said cathode pool.

4. A vapor electric device comprising an evacuated casing, an anode and a pool of vaporizable conductive material serving as a cathode in said casing, and means for controlling the vapor d sity within said casing comprising a fluid cooled coil surrounding said anode and at least a portion, of the space contained between said anode and said cathode pool, said coil comprising spaced turns defining interstices therebetween, and means for closing said interstices of at least the portion of said coil surrounding said anode and leaving the remainder of said interstices pervious to the flow of material vaporized from said cathode pool to the outer surfaces of said coil.

5. A vapor electric device comprising an evacuated casing, an anode and a pool of vaporizable conductive material serving as a cathode in said casing, and means for controlling the vapor density within said casing comprising a fluid cooled coil surrounding said anode and at least a portion of the space contained between said anode and said cathode pool, said coil comprising spaced turns defining interstices therebetween, and a wire applied against the surfaces of adjacent turns of at least the portion of said coil surrounding said anode to close a portion of said interstices to the flow of material vaporized from said cathode pool.

' 6. A vapor electric device comprising an evacuated casing, an anode and a pool of vaporizable conductive material serving as a cathode in said casing, a control electrode disposed between said anode and a second portion surrounding and said cathode pool, and means for controlling the vapor density within said casing comprising a fluid cooled element impervious to the flow of material vaporized from said cathode pool surrounding at least said anode and said control electrode and a fluid cooled element pervious to the flow of material vaporized from said cathode pool surrounding at least a portion of the space contained between said control electrode and said cathode pool.

7. A vapor electric device comprising an evacuated casing, an anode and a pool of vaporizable conductive material serving as a cathode in said casing, a control electrode disposed between said anode and said cathode pool, a battle disposed between said control electrode and said cathode pool, and means for controlling the vapor density within said casing comprising a fluid cooled element impervious to the flow of material vaporized from said cathode pool surrounding said anode, said control electrode and said baflle, and a fluid cooled element pervious to the flow of material vaporized irom said cathode pool surrounding at least a portion of the space contained between said badie and said cathode pool.

8. A vapor electric device comprising a, cylindrical evacuated casing, a cylindrical anode and a pool of vaporizable conductive material serving as a cathode disposed in axial alignment in said casing, control electrode means arranged in close proximity to said anode, bailie means of greater diameter than said control electrode means arranged in close proximity to said control electrode means, and means for controlling the vapor density within said casing comprising a hollow cylindrical fluid cooled element impervious to the flow of material vaporized irom said cathode pool cooperating with said baflle means for confining a space following substantially the contour of said control electrode means and a fluid cooled ele- 8 ment pervious to the flow of material vaporized from said cathode pool surrounding at least a portion of the space contained between said bafiie means and said cathode pool.

9. A vapor electric device comprising an evacuated casing, an anode and a pool of vaporizable conductive material serving as a cathode in said casing, a control electrode disposed between said anode and said cathode pool, a cylindrical fluid cooled coil surrounding said anode, said control electrode and at least a portion of the space contained between said control electrode and said cathode pool, and means for deionizing the space about said control electrode comprising a flat annular baiiie disposed between said control electrode and said cathode pool, a disc-shaped baifle of smaller outside diameter than said annular baiiie disposed between said annular baiile and said cathode pool to define a sinuous path for the discharge between said anode and said cathode pool, said baflies and said control electrode defining a. cylindrical chamber, and a member of conductive material disposed within said chamber to render annular the portion of said sinuous path contained within said annular bafiie.

10. A vapor electric device comprising an evacuated casing, an anode and a. pool of vaporizable conductive material serving as a cathode in said casing, a, flat annular baiile disposed between said anode and said cathode pool, a disc-shaped bafile disposed between said annular baffle and said cathode pool to define a sinuous path for the discharge between said anode and said cathode pool, and means for deionizing the space surrounded by said annular baiiie comprising a conductive member disposed within said annular baiile.

HAROLD WINOGRAD.

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