US2056638A - Rectifier cooling system - Google Patents

Description

Oct. 6, 1936 H. WINOGRAD RECTIFIER COOLING SYSTEM Filed Dec. 17, 1932 Patented Oct. 6, 1936 UNITED STATES PATENT OFFICE RECTIFIER COOLING SYSTEM Application December 17, 1932, Serial No. 647,745

5 Claims.

This invention relates to improvements in electron discharge devices and more particularly to means for maintaining the interior of a device of the vapor type at the most favorable conditions. of pressure and temperature.

- anode thereby causing the occurrence of a socalled backfire. If the vapor pressure is too low, the voltage drop in the arc increases resulting in a reduced efficiency of the device. The are also becomes unstable and permits the establishment of oscillations or surges in the circuits connected therewith. The vapor pressure in the arc path is difficult to regulate as such pressure depends not only on the temperature of the coldest portion of the device but also on the relative temperatures of the different cooling surfaces and on the amount of vapor evolved in the oathode in dependence on the load of the device. The effect of such temperature distribution is such that, even if portions of the cooling surfaces are well cooled, the flow of large amounts of vapor from the cathode to such portions and through the arc path may occur under a relatively high dynamic head so that the pressure of the vapor in the vicinity of the cathode or in the arc path may become excessive. Such condition is particularly difiicult to regulate in water-cooled devices for the largest outputs used at the present time in which the amount of vapor generated is so great that the proper pressure within the device cannot obtain both at low loads and at heavy overloads. In devicesknown heretofore the cooling surfaces adjacent the arc path were more intensely cooled than the remainder of the container surfaces. The result of such cooling was that, upon occurrence of heavy overloads, large amounts of vapor rising from the cathode rushed towards the wall portions adjacent the'arc path whereon such vapor condensed, thereby creating a more or less turbulent zone of high pressure within the arc path resulting in the occurrence of frequent backfires.

If the flow of cooling water is so directed as to first cool surfaces not adjacent to the arc path, any rushes of vapor occurring upon overloads are diverted outside of the arc path and do not cause the establishment of dangerous conditions within the device. In addition, the maximum temperature of the coolest portion of the cooling surfaces may be regulated by thermostatically controlled means.

It is, therefore, among the objects of the present invention to provide an electron discharge device of the vapor type in which the pressure within the arc path is maintained Within permissible limits at all loads.

Another object of the present invention is to provide an electron discharge device of the vapor type in which conditions conducive to backfiring or other disturbances in the operation of the device are avoided.

Another object of the present invention is to provide an electron discharge device of the vapor type in which the maximum temperature of the coolest portion of the cooling surfaces is controlled by thermostatic means.

Another object of the present invention is to provide an electron discharge device of the vapor type in which the cooling surface portions adjacent the arc path are automatically maintained at a temperature higher than the temperature of other portions of the cooling surface.

Another object of the present invention is to provide an electron discharge device of the vapor type in which the several cooling members or surface portions are connected in series to form a single circuit for the flow of cooling water.

Another object of the present invention is to provide an electron discharge device of the vapor type in which the cooling surface portion adjacent the arc path is cooled by water previously circulated through another cooling portion of the device.

Objects and advantages other than those above set forth will be apparent from the following description when read in connection with the accompanying drawing, which diagrammatically illustrates a cross-section of an electron discharge device of the vapor type in which the cooling surface adjacent the arc path is cooled by water previously circulated through an interior'member of the device.

Referring more particularly to the drawing by characters of reference, the reference numeral l designates the double walled bottom of the device which bottom is substantially in the shape of a frustrum of a hollow cone. The aperture through the bottom I is closed by a double walled plate 2 insulated from the bottom as at 3. The plate 2 and the insulation 3 together form a well to retain a quantity of vaporizable material such as mercury which forms the cathode 4 of the device. A double walled cylinder portion 6 extends upwardly from the bottom portion I and the open upper end of the cylindrical portion is closed by a double walled top plate I having a cylindrical upwardly extending portion 8 which is also double walled and forms a dome cooperating with the chamber formed by the bottom I, side walls 6 and top plate I, to condense the vapor rising from cathode 4.

A plurality of anodes I I are arranged to extend into the chamber from the exterior thereof through the top plate 1, the anodes being insulated from the top plate by insulating bushings I2 also extending therethrough. Each of the anodes II is partially enclosed by a housing or are guide I3 extending from the insulator I2 to adjacent the bottom I. A coil of tubing I4 is arranged within the chamber, preferably within the area enclosed by the anodes I I, and may extend within the dome portion 8 as shown in the drawing. In a device constructed as above described, the arc will substantially follow a path from anode II through housing I3 along bottom I to cathode 4 as indicated at I5. It will be understood that the several members of the device are assembled and sealed in vacuum tight relation by the usual well known means (not shown).

The cooling fluid used for controlling the temperature of the device, which is preferably fresh water obtained from distribution mains (not shown), is admitted through an inlet valve I6 which may be used for regulating the flow of such water but will generally serve only to shut off the flow of water to permit disconnection of the device from the water supply mains. The flow of water may first be directed to the chamber enclosed between the walls of cathode plate 2 through tubing H which is generally of insulating material such as rubber hose. The water having circulated within plate 2 flows through another insulating tube section I8 and is then directed through tubing I9 to cooling coil I4. Tubing 2| directs the water from coil I4 over a thermostatic element 22 and through a valve 23 con: trolled by thermostat 22. Valve 23 is bypassed by a manually adjustable valve 24 to permit accurate adjustment and control of the thermostat 22. The cooling water then flows between the two walls of bottom I and of side walls 6, is con ducted through tubing 26 to plate 'I, flows between the double walls of such plate and of dome 8 and is discharged through tubing 21 to a drain 28. A gap is made between tubing 21 and drain 28 in preference to a section of insulating tubing so as to permit visual observation of the flow of water.

In the arrangement shown, the cooling water is first directed to the cathode for the purpose of preventing the portions of the cathode well and the seals thereof from reaching excessive temperatures and for reducing the amount of vapor generated at the cathode but the temperature conditions of the device would not be affected materially even if the cathode were cooled by separate cooling means. The cooling water, at substantially the temperature of the supply mains, thus enters coil I4 which is thereby maintained at a temperature lower than the temperature of any of the other cooling surfaces in contact with the vapor. The vapor generated in the cathode will, therefore, tend to condense on the surface of cooling coil I4 rather than on the other portions of the cooling surfaces and will rise from cathode 4 in a substantially rectilinear flow which takes such vapor outside of the arc path I5. The temperature of the cooling water at the inlet of coil I4, being substantially that of the supply mains, is not controlled but the amount of water circulating through the system is regulated by valve 23 so as tomaintain a substantially uniform temperature at thermostat 22. It will thus appear that the temperature of the hottest point of coil I4 will be maintained at a substantially constant value by the action of thermostat 22 and valve 23 irrespective of the amount of heat received by coil I4 by condensation of vapor and by radiation from anodes I2, from the arc within the device and from the spot formed by attachment of the are on the cathode. Coil I4 will be maintained at the suitable temperature for condensing the vapor generated at cathode 4 irrespective or the amount of such vapor evolved in response to the load carried by the device. If the flow of water were controlled by valve 23 alone no water would circulate through the cooling members when the device has been put in operation and has been allowed to reach substantially room temperature. The water in coil I4 would gradually reach higher temperatures without, however, affecting thermostat 22 as such high temperature water would remain within coil I4. To avoid such failure of thermostat operation, bypass 24 permits the flow of a small amount of water even when valve 23 is closed so that the position of thermostat 22 is determined by the temperature of the outlet of coil I4 even when valve 23 is closed.

It will be seen that bottom I, side wall 6, plate I and dome 3 of the device receive water which has been somewhat heated in coil I4 so that such portions of the device are maintained at a temperature higher than the temperature of any portion of coil I4. The vapor will, therefore, not tend to condense on such portions which then serve only to dissipate heat radiated by the anodes, by the arc and by the cathode spot. The vapor generated at the cathode, in excess of the amount to be ionized in the arc path, therefore flows substantially entirely outside of the arc path and permits the flow of the arc in a region undisturbed by excessive pressures caused by the flow of such vapor.

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.

It is claimed and desired to secure by Letters Patent:

1. In combination with an electron discharge device of the arcing type comprising a casing having an aperture therein and being provided with double walled portions forming a passage for the flow of cooling medium therethrough, a receptacle containing a quantity of vaporizable cathode material closing said aperture and having a double walled portion forming a passage for the flow of cooling medium therethrough, a plurality of anodes depending into said casing, and an element supported within said casing within the area defined by said anodes having a passage therethrough for the flow of cooling medium, of means interconnecting said passages in such manner as to form a continuous path for the flow of a cooling medium supplied thereto successively through the second, third and first said passages whereby the coolest surfaces for condensation of vaporized portions of said cathode material are disposed outside the path of arcs between the said anodes and cathode, and means operable responsive to and in dependence upon the temperature of said medium flowing from the third said passage into the first said passage for regulating the rate of flow thereof therethrough.

2. In combination with an electron discharge device of the arcing type comprising a casing having an aperture therein and being provided with double walled portions forming a passage for flow of cooling medium therethrough, a receptacle containing a quantity of vaporizable cathode material closing said aperture and having a double walled portion forming a passage for flow of cooling medium therethrough, a plurality of anodes depending into said casing, and means comprising a coil of tubing supported within said casing within the area defined by said anodes constituting a passage for flow of cooling medium therethrough, of means interconnecting said passages in such manner as to form therewith a continuous path for the flow of cooling medium supplied thereto successively through the second, third and first said passages whereby vapor created from said cathode material is drawn away from the paths of arcs between said anodes and cathode, a valve included in the connections of said medium with said passages for regulating the rate of flow thereof, and means operable responsive to and in dependence upon the temperature of said medium flowing from the third said passage into the first said passage for variably operating said valve.

3. In combination with an electron discharge device of the arcing type comprising a casing having an aperture therein and being provided with double walled portions forming a passage for the flow of cooling medium therethrough, a receptacle containing a quantity of vaporizable cathode material closing said aperture and having a double walled. portion forming a passage for flow of cooling medium therethrough, a plurality of anodes depending into said casing, and means comprising a coil of tubing supported within said casing within the area defined by said anodes constituting a passage for the flow of cooling medium therethrough, of means interconnecting said passages in such manner as to form a continuous path for flow of a cooling medium supplied thereto successively through the second, third and first said passages whereby vapor created from said cathode material is drawn away from and condensed outside of the paths of arcs between said anodes and cathode, a valve included in the connections of said medium with said passages for regulating the rate of flow thereof, thermostatic means operable responsive to and in dependence upon the temperature of said medium flowing through said passages for variably operating said valve, and a by-pass about said valve forming a path for flow of said medium through said passages during periods of closure of said valve.

l. In combination with an electric current rectifier having a closed casing and containing vaporizecl electrode material, of means forming a path for the flow therethrough of a cooling medium continuously supplied thereto and arranged in such position within said casing as to afiect the direction of fiow of said vaporized material, and means operable responsive to and in dependence upon the temperature of said medium flowing from the first said means for regulating the rate of flow of said medium therethrough.

5. In combination with an electric current rectifier having a closed casing and containing vaporized' electrode material, of means comprising a coil forming a path for the flow therethrough of a cooling medium continuously supplied thereto and arranged in such position within said casing as to affect the direction of flow of said vaporized material, and means operable responsive to and in dependence upon the temperature of said medium flowing from said coil for regulating the rate of flow of said medium therethrough.

HAROLD WINOGRAD.

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