US1985511A

US1985511A - Electric current rectifier

Info

Publication number: US1985511A
Application number: US546527A
Authority: US
Inventors: Othmar K Marti
Original assignee: Allis Chalmers Corp
Current assignee: Allis Chalmers Corp
Priority date: 1931-06-24
Filing date: 1931-06-24
Publication date: 1934-12-25
Anticipated expiration: 1951-12-25

Description

Deg. 25, 1934.

O. K. MART! ELECTRIC CURRENT RECTIFIER Filed June 24, 193 1 I ventar I Of/mar K. Marti Bym ttarney Patented Dec. 25, 1934 UNITED STATES PATENT OFFICE ELECTRIC CURRENT RECTIFIER tion of Delaware Application June 24, 1931, Serial No. 546,527

7 Claims.

This invention relates to improvements in electric current rectifiers of the metallic vapor type and particularly to systems for the circulation of a cooling medium through portions of the rectifier structure for the purpose of controlling the vapor density therein.

When electric current rectifiers of the metallic vapor type are constructed for power purposes, the metallic vapor carrying the current within the rectifying structure is enclosed within a metallic tank which is usually formed with hollow walls to provide a path for the circulation of a cooling medium therethrough. Coils of tubing may also be arranged within the tank to form a path for the circulation of a cooling medium therein. Such circulation of a cooling medium reduces the temperature within the tank thereby reducing the vapor pressure and preventing condensation of the metallic vapor on portions of the tank structure where the presence of vapor would injuriously affect the operation of the rectifier. It has been found, however, that the circulation of a cooling medium merely through the hollow walls of the tank and cooling coils connected in series therewith in one continuous path does not permit the abstraction of heat in such manner as to permit the required temperature distribution within the rectifier to be obtained.

It is, therefore, among the objects of the present invention to provide a rectifier construction in which the temperature in difierent portions thereof may be accurately controlled.

Another object of the invention is to provide a rectifier construction in which the'difierent portions of the rectifier are cooled by separate cooling systems having difierent rates of heat transfer thereto.

Another object of the invention is to provide a rectifier construction in which the tank of a rectifier is a portion of a closed recirculating cooling system supplied with a cooling medium at a certain temperature and the cathode and internal cooling coils of the rectifier are portions of a cooling system supplied with a cooling medium at a lower temperature.

Objects and advantages, other than those above set forth, willbe apparent from the following descriptionwhen read in connection with the accompanying drawing which somewhat diagrammatically illustrates one embodiment of the present invention. I

Referring more particularly to the drawing by characters of reference, the reference nu-' meral 1 .generallydesignates 'a metallic tank formed with double walls to provide a jacket through which a cooling medium is to be circulated. An aperture in the bottom'of the tank 1 is closed by a double walled plate 3 which is insulated from the tank as at 2 thereby forming a well which contains a suitable cathode material such as metallic mercury. The plate 3 conducts the current to the output circuit and may be of any construction or material which is suitable as is known in the art. The insulation 2 between the cathode plate 3 and the tank 1 is preferably of a material such that the plate may be sealed in gas-tight relation to the tank. Such insulation is shielded from the action of the are within the rectifier by a cylinder 5 of refractory insulating material such as quartz having the upper end thereof flared or funnelshaped and which is held against the plate 3 by a ring secured on the bottom of the tank. When the rectifier is in operation, an arc flows from the anodes 10 to the cathode 4. formed by the mercury in the well 2, 3 as is well-known, thereby vaporizing a portion of the mercury which must be condensed by contact with the cooled portions of the device.

A cooling medium such as water is supplied from a suitable source (not shown) toa circulating system comprising a pipe 6, a coil 7 within a tank 8 in which some water is always retained, the cathode plate 3, and a cooling coil 11 extending downwardly into the rectifier from the top thereof. It will be seen that the cooling coil 11 is arranged within the rectifier at the point thereof to whichthe major portion of the vaporized mercury will rise. The supply of water to the above A cooling system is controlled by a valve 9 which is operated in response to a thermostatic device 12 arranged Within the drain 13 from the coil 11. The quantity of water delivered to the plate 3 and to the coil 11 is thus controlled in response to the temperature of the water discharged from the coil. The admission of water to the space between the walls of the tank 1 from the tank 8 through a pipe 16 under the action of a pump 18 is governed by a valve 21 which is controlled by a thermostatic device 22 in the cooling medium circulating through the walls. Suitable insulating connections consisting of lengths of insulating conduits such as rubber hose are inserted as shown in the piping which would otherwise electrically connect parts of the rectifier at different potential.

In operation, cold cooling fluid is drawn from the source through valve 9 into coil 7 which is immersed in tank 8. The fresh supply of cooling a aka medium is then directed to the cathode plate 3, which requires intense cooling due to the large amount of heat liberated on the comparatively small cathode area, and is thereafter directed through coil 11. The coil 11 is located partially in the cooling dome of the rectifier and partially in the working cylinder and is constructed with an extremely large cooling area so that the major portion of the mercury vapor rising from the cathode is condensed thereby. The cooling medium discharged from the coil 11 is directed on the thermostatic element 12 which opens the valve 9 when the fluid leaving the coil 11 is above a predetermined temperature and which closes the valve 9 when the fluid is discharged from the coil 11 below a predetermined temperature so that the temperature of the coil ll is always maintained at a suitable value independently of the amount of mercury vapor generated in response to the momentary load on the rectifier. It may e found desirable, in some instances, to direct the cold cooling medium first through the cathode plate 3 to cool the same more intensely, in which case coil '7 is inserted between the cathode plate and the cooling coil 11 rather than between the source and the cathode plate 3 as shown. The fluid in the other circuit, the closed recirculating cooling system, is heated by the condensation of the mercury vapor on the walls of the cylinder and on the walls of the tank cover and is moderately cooled in tank 8 by the fresh supply of cooling medium flowing through coil '7 so that the cooling medium enters the double walls of the tank at a temperature only slightly below the temperature at which the cooling medium is drawn from the double walls of the cooling done by the pump 18. The-temperature of the walls is thus maintained substantially uniform and at a value determined by the thermostat 22 which regulates valve 21 in a similar manner to the regulation of valve 9 by thermostat 12. The proper vapor pressure and temperature may thus be obtained in the tank and in particular in the vicinity of the anodes at values most suit able for the successful operation of the rectifier.

It will be seen that the present invention provides a rectifier construction in which the rectifier is cooled by two entirely separate circulatory systems of which one system is a closed recirculating system by which portions of the rectifier structors are only moderately cooled and the other system is continuously supplied with fresh water which intensively cools the portion of the rectifier from which the metallic vapor rises and to which the major portion of the metallic vapor is to flow. The general direction of the flow of the vapor may thus be controlled. The quantity of water circulating through both systems is thermostatically controlled thus permitting a more accurate control of the temperature and hence of the vapor density than was possible heretofore. Due to the thermostatic control, the amount of cooling accomplished by either circuit remains constant regardless of the temperature of the water supplied thus maintaining uniform operating conditions within the rectifier.

Although but one embodiment of the present invention has been illustrated and described, it will be apparent to those skilled in the art that various changes and modifications may be made therein without departing from the spirit of the invention or from the scope of the appended claims.

The invention claimed is:

1. In means for cooling an electric current recs tifier, the combination of a casing having an aperture therein and being provided with a plurality of passages forming a path for the flow of cooling medium, a receptacle containing a quantity of vaporizable electrode material closing said aperture and having a double walled portion forming a path for the flow of a cooling medium therethrcugh, a closed cooling system operable to cause the recirculation of a constant quantity of cooling medium through, the first said path, and a second cooling system operable to cause the fiow of a cooling medium continuously supplied thereto through the second said path and comprising means operable to recool the fluid flowing in the said closed cooling system, the fiow of said cooling mediums through the respective said paths being co-jointly operable to regulate the rate of vaporization of said material to affect the direction of flow of vaporized portions thereof and to effect condensation thereof.

2. In means for cooling an electric current rectifier, the combination of a casing having an aperture therein and being provided with a plurality of passages forming a path for the flow of a cooling medium therethrough, a receptacle containing a quantity of vaporizable electrode material closing said aperture and being provided with a passage forming a path for the flow of a cooling medium therethrough, a closed cooling system operable to cause the recirculation of a I constant quantity of cooling medium through the first said path, said system including means operable to regulate the rate of flow of said medium through said path, and a second cooling system operable to cause the flow of a cooling medium 5 continuously supplied thereto through the secend said path and comprising means operable to recool the fluid flowing through the said closed cooling system, the flow of said cooling mediums through the respective said paths being co-jointly operable to regulate the rate of vaporization of said material, to afiect the direction of flow of vaporized portions thereof and to effect condensation thereof.

3. In means for cooling an electric current rectifier, the combination of a casing containing a quantity of vaporizable electrode material and being provided with a plurality of passages forrning paths for the flow of cooling medium, a closed cooling system operable to recirculate a constant quantity of cooling medium through one of said paths, said system including means operable responsive to and in dependence upon the temperature of said medium flowing from the said one of said paths for controlling the rate of flow thereof, and a second cooling system operable to cause the flow of a 'v ariable quantity of cooling medium continuously supplied thereto through another of said paths, the said second system including means operable to recool the fluid flowing in the said closed cooling system and means operable responsive to and in dependence upon the temperature of the cooling medium flowing from the said another of said paths for controlling the quantity of cooling medium supplied thereto, the said systems being co-jointly operable to affect the direction of flow of vaporized portions of said material and to effect the condensation thereof in dependence upon the rates of flow of said mediums through the respective said paths.

4. In means for cooling an electric current rectifler, the combination of a. casing containing a quantity of vaporizable electrode material and being provided with a plurality of passages about .the walls thereof forming paths for the flow of cooling medium, a closed cooling system operable to recirculate a constant quantity of cooling medium through certain ones of said passages, and a second cooling system operable to cause the How of a variable quantity of cooling medium continuously supplied thereto through another of said passages, the said second system including a coil supported within said casing constituting a portion of the path for the flow oi the second said medium, the said systems being co-jointly operable to regulate the rate of vaporization of said material, to affect the direction of flow of vaporized portions thereof, and to eiiect condensation thereof.

5. In means for cooling an electric current rectifier, the combination of a casing containing a quantity of vaporizable electrode material and being provided with a plurality of passages constituting paths for the flow of cooling medium about the Walls thereof, a closed cooling system operable to recirculate a constant quantity of a cooling medium through certain of said passages, a second cooling system operable to cause the flow of a variable quantity of a cooling medium continuously supplied thereto through another of said passages, the said second system including a coil supported within said casing constituting a portion of the path for the flow of the second said medium, and means operable responsive to and in dependence upon the temperatures of the mediums flowing from the respective said paths for controlling the rates of flow thereof, the said systems being co-jointly operable to regulate the rate of vaporization of said materiahto affect the direction of flow of vaporized portions thereof, and to affect the rates of condensation thereof in dependence upon the rates of flow of said mediums.

6. In means for cooling an electric current rectifier, the combination of a casing containing a quantity of vaporizable electrode material and being provided with a plurality of passages constituting paths for the flow of cooling medium about the walls thereof, a closed cooling system comprising a receptacle containing a constant quantity of cooling medium and means for causing the recirculation thereof through certain of said passages, a second cooling system operable to cause the flow of a variable quantity of cooling medium continuously supplied thereto through another of said passages, the said second system including a coil supported within said casing and means supported within said receptaole constituting portions of the path for the flow of the second said medium, the flow of the second said medium through the said another of said passages and through the said coil being operable to cool the area of vaporization of said material, to affect the direction of flow of vaporized portions of said material and to effect condensation thereof, and the flow of the second said medium through the said means being operable to recool the first said medium.

7. In means for cooling an electric current rectifier, the combination of a casing containing a quantity of vaporizable electrode material and being provided with a plurality of passages constituting paths for the flow of cooling medium about the walls thereof, a closed cooling system comprising a receptacle containing a constant quantity of cooling medium and means for causing recirculation thereof through one of said passages, means operable responsive to and in dependence upon the temperature of said-medium flowing from said one of said passages for regulating the rate of recirculation thereof, a sec ond cooling system operable to cause the flow of a variable quantity of cooling medium continuously supplied thereto through another of said pasages, the said second system including a coil supported within said casing and means supported within said receptacle constituting portions of the path for the flow of the second medium, the flow of the second said medium through the said another of said passages and through the said coil being operable to cool the area of vaporization of said material, to aifect the direction of flow of vaporized portions thereof and to effect condensation thereof, the flow of the second said medium through the said means being operable to recool the first said medium, and means operable responsive to and in dependence upon the temperature of the second said medium flowing from said coil for regulating the quantity of cooling medium supplied to the said second system.

OTHMAR K. MARTI.