US3252041A - Grid support for mercury arc rectifier - Google Patents

Description

United States Patent one 3,252,041 Patented May 17, 1966 3,252,041 GRID SUPPORT FOR MERCURY ARC RECTIFIER Harold Ernest Aldworth, Shalford, Guildford, and Zygmunt Sawko, Stafford, England, assignors to The English Electric Company Limited, Strand, London, England, a British company Filed Oct. 5, 1962, Ser. No. 228,689 Claims priority, application Great Britain, Oct. 11, 1961, 36,480/61 4 Claims. (Cl. 313-265) This invention relates to mercury arc rectifiers and is concerned with .the problem of supporting and cooling the grid.

It is an object of the present invention to provide a grid support structure which is contained entirely within the valve envelope and is not built into it by any metal joining process.

According to the invention, a mercury arc rectifier includes an annular electro-conductive envelope mounted between axially spaced insulating walls and agrid supported from within the envelope through mounting means which also serve to provide an electrical connection between the envelope and the grid.

According to a preferred feature of the invention, the envelope extends outwardly beyond the periphery of the insulating walls and the mounting means includes a generally axially extending annular electro-conductive support member carrying at its lower end an annular grid and having at its upper end a flange portion which extends outwardly into the envelope and which is supported within the envelope by a plurality of spring members which also provide an electrical connection between the envelope and the flange portion.

According to another preferred feature of the invention the annular support member is hollow and provides a first hollow portion at said lower end for the reception of liquid mercury or the like and a second hollow portion constituted by said flange portion and in communication .with the first hollow portion, the arrangement being such that heat is transferable from the grid to the envelope by phase change of the mercury which evaporates in the first hollow portion, ascends to and condenses in the second hollow portion, and returns to the first hollow portion by the action of gravity.

Further preferred features of the invention will appear from the following description with reference to the accompanying drawing wherein is shown one arrangement of mercury arc rectifier according to the invention.

Referring now to the drawing, the mercury arc rectifier includes a valve envelope generally indicated at and mounted between axially spaced ceramic insulating walls 11. An annular grid 12 is secured at a joint 13 to a. grid support member generally indicated at 14. The grid support member 14 comprises a vertically disposed hollow tubular portion 15 butt welded at the upper end thereof to an outwardly extending hollow flange portion 16. The hollow construction of the support member 14 'provides an annular enclosure 17 containing a mercury pool 18. A tubular shield 19 extends upwardly from the support member 14.

The valve envelope 10 consists of welded segments 20, 21, 22 and 23 arranged to provide an annularly shaped internal recess 24 and two re-entrant annular spaces 25 and 26. The flange portion 16 of the support member 14 is located and resiliently supported within the recess 24 by means of nimonic alloy strip springs 27 which also provide the necessary electrical connection to the grid. A baffle structure 28 surrounds the valve envelope 10 and is separated therefrom by electro-conductive nimonic alloy strip springs 29. The baffle structure 28 provides an oil flow path indicated by the arrowssuch that oil may be caused to flow over the surfaces of the valve envelope 10 in a tortuous path. A resilient annular member 30 attached to an annular ceramic outer wall 31 exerts radial pressure on the baflle structure 28 and acts as a barrier to oil tending to by-pass the path shown by the arrows. The annular member 30 is provided with axial slits (-not shown) to give flexibility. A slight oil by-pass is. therefore unavoidable.

Heat flows from the grid across the joint 13 and causes boiling in the mercury pool 18. The vapour so produced ascends to the flange portion 16, condenses, and returns to the pool 18 by gravitational action. Heat is transferred from the flange portion -16 to the valve envelope 10 by radiation and thence by convection to oil coolant flowing over the walls of the envelope in the path indicated by the arrows.

What we claim as our invention and desire to secure .by Letters Patent is:

1. A mercury arc rectifier having, in combination, an envelope including two coaxially disposed non-conducting tubular members spaced axially from each other by a conducting tubular member forming a tubular cavity between the two non-conducting members of larger cross section than the non-conducting members, a grid member within the envelope having a flange portion projecting into, but spaced from, the cavity, and resilient mounting means within said cavity providing both a support for the grid member and an electrical connection between the gridmember and the tubular conducting member.

2. A mercury arc rectifier having, in combination, an envelope including two coaxially disposed non-conducting tubular members spaced axially from each other by a conducting tubular member forming a tubular cavity between the two non-conducting members of larger cross section than the non-conducting members, a grid member within the envelope having a flange portion projecting into, but spaced from, the cavity, and a plurality of generally U- shaped corrugated springs interposed between the flange portion of the grid member and the inside faces of the tubular cavity providing both a support for the grid member and an electrical connection between the grid member and the tubular conducting member.

3. A mercury arc rectifier having, in combination, an envelope including two coaxially disposed non-conducting tubular members spaced axially from each other by a conducting tubular member forming a tubular cavity between the two non-conducting members of larger cross section than the non-conducting members, a grid member within the envelope having a flange portion projecting into, but spaced from, the cavity, and resilient mounting means within said cavity providing both a support for the grid member and. an electrical connection between the grid member and the tubularconducting member, the grid member having an annular cavity below the flange portion communicating directly with an annular cavity within the flange portion and which contains mercury or the like so that, in operation, heat may be transferred from the grid member to the flange member by phase change of the mercury or the like.

4. A mercury arc rectifier having, in combination, an envelope including two coaxially disposed non-conducting tubular members spaced axially from each other by a conducting tubular member forming a tubular cavity between the two non-conducting members of larger cross section than the non-conducting members, a grid member within the envelope having a flange portion projecting into, but spaced from, the cavity, resilient mounting means 3 within said cavity providing both a support for the grid member and an electrical connection between the grid member and the tubular conducting member, the grid member having an annular cavity below the flange portion communicating directlyLWith an annular cavity within the flange portion and which contains mercury or the like so that, .in operation, heatmay be transferred from the grid member to the flange member by phase change of the mercury or the like, a tubular conducting bafiiemember disposed around, but spaced from, the tubular conducting member so as.to-guide coolant over the tubular conducting member, and Second resilient mounting means providing both a mounting for the bafiie member and an electrical connection between the baflie member and the tubular conducting member.

References Cited by the Examiner UNITED STATES PATENTS 2,873,954 2/1959 Protze 313-24 X JOHN W. HUCKERT, Primqry EXaminer. GEORGE N. WESTBY, Examiner. L. ZALMAN, Assistant Examiner.

Claims (1)

1. A MERCURY ARC RECTIFIER HAVING, IN COMBINATION, AN ENVELOPE INCLUDING TWO COAXIALLY DISPOSED NON-CONDUCTING TUBULAR MEMBERS SPACED AXIALLY FROM EACH OTHER BY A CONDUCTING TUBULAR MEMBER FORMING A TUBULAR CAVITY BETWEEN THE TWO NON-CONDUCTING MEMBERS OF LARGER CROSS SECTION THAN THE NON-CONDUCTING MEMBERS, A GRID MEMBER WITHIN THE ENVELOPE HAVING A FLANGE PORTION PROJECTING INTO, BUT SPACED FROM, THE CAVITY, AND RESILIENT MOUNTING MEANS WITHIN SAID CAVITY PROVIDING BOTH A SUPPORT FOR THE GRID MEMBER AND AN ELECTRICAL CONNECTION BETWEEN THE GRID MEMBER AND THE TUBULAR CONDUCTING MEMBER.

Images