US1075402A

US1075402A - Vapor electric device.

Info

Publication number: US1075402A
Application number: US74405913A
Authority: US
Inventors: Francis P Coffin
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1913-01-25
Filing date: 1913-01-25
Publication date: 1913-10-14
Anticipated expiration: 1930-10-14

Description

F. P. GOPFIN.

VAPOR ELECTRIC DEVICE.

APPLICATION FILED JAN. 25, 1913.

Patented Oct. 14, 1913.

Inventor Francis P. Cofin,

Witnesses:

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FRANCIS P. COFFIN, 0F SCHENECEDADY, NEW YORK, ASSIGNOR T0 GENERALELECTRIC 'OGM-P-A-NY, A CORPORACLION OF NEW YORK.

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Specification of -Letters' Patent.

Patented @ct. Ital, 1913..

To all whom it may concern:

Be it known that 1, FRANCIS P. Corrru,

a citizen of the United States,-resident of Schenectady, county'of Schenectady, State of New York, have invented certain new and useful Improvements in Vapor Electric Devices, of which't'he'following is a specification.

The present invention relates to mercury vapor devices and-particularly to the construction of large, high powered vapor rectifiers having metal containers. @ne of the main problems in the operation of these high powered rectifiers is the maintenance of steadiness in the arc. lln devices as heretofore constructed the cathode spot is apt to temporarily jump to the metal wall 'of the cathode chamber, especially when mercury globules have condensed on the wall, thus causing the arc to be temporarily extinguished, or as it is termed, causing winking of the arc.

In accordance with my invention the metal cathode chamber is insulated from the main arc chamber, and is also provided with a refractory insulating ring or lining overlapping with said insulation for confining the arc and preventing it from injuring the insulation by its heating action and from climbing up the metal surface.

The structural details of the cathode chamber of the rectifier are shown in the sectional view in Figure 1 and the relation of the cathode to the other parts of the rectifier are shown respectively by the side and top View in Figs. 2 and 3.

As shown in Fig. 2 the rectifier consists of a main arc chamber 1 to which is joined a cathode chamber 2, insulated therefrom as will be described. In the main arc chamber there are anodes 3 and d surrounded by shields 5 and 6 of suitable refractory material such as silica, alumina or the like. Two anodes have been indicated but of course, any number of anodes may be used. The cathode chamber communicates with the main arc chamber by means of a throat 7 as clearly shown in Fig. 1. This throat is joined preferably by welding to the wall 8 of the main envelop and also to an annular disk of metal 9. For convenience of welding the part 9 is recessed near its juncture with its throat 7 to reduce the amount of metal. After the weld has been made a threaded ring 10 is preferably driven into vthis'rec'ess to which may besecured the lower or hanging section of the throat. To the metal cathode vessel is joined another annular disk or fiange 11 through which pass 'a number of bolts 12, two of which are shown. These bolts are insulated from the cathode container by a sleeve 13 of fiber or like material. Asbestos molded with a hinder or" a phenol-formaldehyde condensation product is suitable for this purpose. The bolts are provided with nuts 14 at either end and spring washers 15.

' Interposed between the cathode cup 2 and the flange 9 is an annular section of insulat-ion...16. The particular insulation illustrated consists of a ring of porcelain upon each side of which bear

pressure distributing plates

17 and 18. Aluminum washers 'are provided between the

plates

17 and 18 and the adjoining metal wall of the con tainer. As indicated washers of yielding material, such as asbestos and lead, or rubher, are used between the porcelain cylinder 16 and the

plates

17 and 18. By tightening the nuts 14, a perfectly vacuum-tight seal may be made. This asbestos may be impregnated with a cementing material so that when hardened the porcelain and the pressure distributing plates may be handled as one unit.

Lining the cathode pot 2 and extending beyond the insulating ring 16 is a refractory lining or cylinder 19 consisting of silica, alumina and similar refractory insulating material. It is a function of this insulating lining to confine the active surface of the cathode upon which the cathode spot plays and thus to prevent wandering of the cathode spot up the side of the metal wall of the cathode pot. My experiments have shown that unless such a barrier is provided a cathode spot will soon injure the insulation between the cathode chamber and the main arc chamber. The ring 19 also serves to protect the insulation from the direct heating action of the are. It is assisted in this heat shielding function by the lower hanging wall of the throat. I have found that if it is attempted to locate this insulation at some distance from the active part of the cathode, and thus to prevent its overheating, globules are condensed on the intervening wall. The are is very apt to jump to these globules of mercury causing unsteadiness of the arc and defeating the very pur ose for which the cathode was insulate If desired the ring or wall 19 may be cemented into direct contact with the insulation 16 but this is not necessary. In the drawing the ring 19 is shown as floating in the mercury, it being forced into contact with the plate 18 by its buoyancy.

The anodes are made vacuum-tight and insulated similarly to the cathode, as indicated in Fig. 2 by

seals

20 and 21. The rectifier is started in operation by drawing an are between the cathode 22 and the rod 23 consisting of molybdenum or other metal. This may be done automatically by means of a magnet 24 which draws up its plunger and lifts the rod 23 drawing the are. The rod 23 is finally drawn up into a graphite sleeve 25. The are is transferred to this sleeve which acts as a sustaining electrode in a well known manner during the operation of the device. The graphite sleeve is attached to a metal tube 26, the lower end of which is indicated in Fig. 1 and to which the plunger mechanism is bolted. The main chamber 1 of the rectifier is preferably maintained at the potential of the sustaining anode by electrically connecting it thereto.

A rectifier constructed as above will carry loads of hundreds of kilowatts continuously.

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

chamber, said lining overlapping the insulation separating said chamber from the main arc chamber.

2. In a vapor electric high powered rectifier, a main evacuated metal chamber, a mercury cathode, a metal chamber therefor opening into said main chamber, vacuumtight insulation between said chambers, and a refractory insulating sleeve interposed between said insulation and the active surface of the cathode.

3. A vapor electric device comprising communicating evacuated metallic chambers, at least one anode in one of said chambers, and a mercury cathode in the adjoining chamber, a vacuum-tight insulating seal between said chambers at a point removed from said cathode, a barrier of insulating material lining the cathode chamber overlapping with said seal and inclosing the active portion of the cathode and a wall of metal confining the are.

4:. In a vapor electric device, a main evacuated metal container, a communicating metal chamber, an easily vaporizable cathode therein, vacuum-tight insulation between said chambers, a sleeve of refractory material confining the active portion of said cathode, and arc-directing means pro jecting from said main chamber, and projecting into said sleeve.

In witness whereof, I have hereunto set my hand this 23rd day of January 1913.

' FRANCIS P. COFFIN.