US1894806A - Arc discharge device - Google Patents

Description

Jan. 17, 1933. F. P; WHITAKER ARC DISCHARGE DEVICE Filed March 12, 1932 Invent 0P 2 Frank P. WhiLaKeP, b9

His AttoPne which may Patented Jan. 17, 1933 PATENT Fries 1P. WHITAKER, OF RUGBY, ENGLAND, ASSIGNOR TO GENERAL ELECTRIC COM PANY,

A CORPORATION OF NEW YORK ARC DISCHARGE DEVICE My invention relates to are discharge devices such as mercury arc rectifiers, more par ticularly to the construction of the shields for the anodes of these devices, and its principal -'obje'ct is the provision of an anode shield construction whereby the output oi the devices is increased.

It is general practice in mercury arc rectifiers to provide each anode with a shield, take the form of a cylinder which surrounds the anode at its upper end and which is open at its lower end so that the arc can reach the anode. It has been proposed to provide an aperture in the side of this shield which is connected to a part of the rectifier which is eificiently cooled, so as to reduce the vapor pressure existing around the anode under certain conditions.

It has been further proposed, in an anode "shield provided with one opening for the normal arcpath between anode and cathode, to provide an additional opening or openings at the top or in the side of the shield, near the anode active surface and not shielded therefrom by baffles, the latter opening or openings being comparable in area with the opening for the normal arc path. In order that the arc might prefer to follow its normal path under usual load conditions, the addi- "tional opening or openings were provided with a high ratio of surface to area of opening to facilitate deionization of incoming mercury vapor.

In accordance with my present invention "I provide an anode shield construction somewhat similar to the latter above described. In the present invention, however, the shield structure is used in conjunction with a special form of container. The anodes are mounted between an outer cylinder and an inner cylinder which extends a substantial distance below the anodes. The deionizing surfaces, which may be fins forming grilles or screens protecting the opening at the top of the cylinder, divide up the greater portion of the spaces or sectors allotted to each anode between the inside and the outside cylinders. The usual cylindrical shields may be dispensed with, the grilles or screens themselves Application filed. March 12, 1832, Serial No. 598,517, and in Great Britain March 11, 1931.

being depended on to subdivide the path for the arc.

My invention will be better understood from the following description when considered in connection with the accompanying drawing and its scope will be'pointed out :in

he appended claims.

Referring to the drawing, Fig. 1 is a sectional view of an arc discharge device in which my invention has been embodied; Fig. 2 is a cross-sectional view on line 2-2 of Fig. 1; Figs. 3 and 4 are cross-sectional views illustrating modifications of the invention; Fig. 5-is a sectional view illustrating a further modification; and Fig. 6 is a cross-sectional view on line 66 of Fig. 5. e

In Figs. 1 and 2, the numeral 1 represents a container or tank tor a rectifier containing six anodes designated by the numerals 2 to 7 Each anode is provided with a shield 8 and with a plurality of deionizing fins or grille members 9 which divide up the space or sector, allocated to each anode, which is between the outer cylinder and an inner cylinder 10. These spaces or sectors may be divided oii from each other by means of radial partitions 11 although in some cases these may be dispensed with. Openings 12 are formed in the upper portion of each shield 8 providing an additional path to the anode for the arc, the normal path of which comprises the opening at the. bottom of the shield. The fins 9 extend downwardly from a point above the opening or openings-12 to a point a substantial distance below these open ings and a substantial distance below the lower face of the anode, thus dividing up the greater portion of the space 13 allotted to each anode.

In the modification shown in Fig. 3, while the fins 9 are connected to the anode shield 8 as Figs. 1 and 2, the fins are of different widths in order to divide up more completely the space allotted to the anode.

The deionizing fins may be connected to the anode shield 8 as shown in Figs. 1, 2 and 3 or they may be connected to the container 1 and inner cylinder 10 as shown in Fig. 4:.

"In the form of the invention illustrated in Figs. 1 and 2 as the anode shield 8 extends downwardly a substantial distance below the anode, the shield thus comprises a lower portion 14 below the additional arc openings 12 and inside the lower ends of fins 9. This 5 lower portion 14 of the anode shield may be omitted, however, as shown in Figs. 5 and 6. In the construction illustrated in the latter figures the shield 15 is short, the lower ortion corresponding to portion 14 of Fig. 1

ing dispensed with, radiating fins 16 being provided which extend below the lower face of the anode 12 and which may be provided with extensions 17 projecting inwardly below the anode.

It is preferable, in any of the modifications .of'the invention illustrated herein, to provide the radial partitions 11 between the tank 1 and inner cylinder 10 although these p la'tions are not always absolutely essential;

Ihwill be readily understood that in any of the modifications of my invention herein described the grille or screen members may be somounted as to beat the potential of the container or tank 1, or they may be so mounted-as to be insulated from the tank, for the p ose, for -'example, of connecting the gril as or screens to leads which are connected to a source of potential whereby the grille or screenstructures may be employed as grids or control electrodes to control the starting of the rectifier.

The number of screen members or fins in each case and the distance between these members should be so determined that arcback is prevented.

With an anode shield construction comprisin thefin or grille arrangement above descri ed in accordance with my invention the size of the rectifier maybe-reduced as compared with those'at present in use of equal power.

It has hitherto been usual'to deionize only the space inside the anode shield. With the construction disclosed herein each sector of the tank may form the anode shield and each sector will be fitted with deionizing fins or grilles sothat the customary anode shield may be omitted; 1

What I claim as new and desire to secure by Letters Patent of the United States is:

1. In an arc discharge device comprising anrevacuated container and a cathode and anode mounted therein, an anode screen structure-mounted in said container adjacent the active surfaces of said anode and comprising a pluralityof relatively closely spaced arc sub-dividing elements extending in a direction laterally of the anode and a plurality of 'arc sub-dividing elements extending in a direction downwardly of the anode, said screen structure'providing relatively long and narrowpassages throughout substantially all the space surrounding the active surfaces of the anode;

screen structure providing relatively long and narrow passagesthroughout substantiall all of the space surrounding the active sur aces of the anode.

3. In an arc discharge device comprising an evacuated container and a cathode and anode mounted therein, an anode screen struc- :ture mountedin said container comprising;

a series of relatively closely spaced ,L-shape r fin-like members arranged edgewise to'said anode and having a leg portion positioned longitudinally of said anode and a foot portion positioned underneath said anode, said screen structure providing relatively 1011 and narrow passages throughout substantiaE ly all of the space surrounding the active surfaces of said anode.

4. In an arc discharge device comprising an evacuated container and a cathode and anode mounted therein, an anode screen structure mounted in said contalner comprising a plurality of relatively closely spaced fin-likiamembers arranged edgewise to said anode and extending along the sides and underneath 1 said anode, said screen structure providing relatively long and narrowpassages throughout substantially all of the space surrounding the active surfaces of said anode.

In witness whereof, I have hereunto set my hand.

FR ANK P. WHITAKER.

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