US1987338A - Mercury vapor rectifier - Google Patents

Description

Jan. 8, 1935. R. M. HEINTZ 1,987,338

MERCURY VAPOR RECTIFIER Filed Sept. 12, 1932 INVENTOR RALPH M HE/NTZ.

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ATTORNEY Patented Jan. 8, 1935 PATENT OFFICE MERCURY VAPOR RECTIFIER Ralph M. Heintz, Palo Alto, Calif., assignor to Heintz & Kaufman, Ltd, San Francisco, Calif., a corporation of Nevada Application September 12, 1932, Serial No. 632,784

5 Claims.

My invention relates to a mercury vapor rectifier and, more particularly, to such a rectifier in which portions of the envelope and anode are spherical and concentric, and in which the oathode is located in the common center of the spherical portions.

Among the objects of my invention are:

To provide a mercury vapor rectifier which a minimum heat radiation.

To provide a mercury vapor rectifier in which the anode shields the cathode from the rectifier walls.

To provide a mercury vapor rectifier which is economical in cathode current.

To provide a small and compact rectifier which can be used at high outputs.

And to provide a mercury vapor rectifier in which the heat generated in the vapor by ionization is used to aid the heating of the cathode.

Other objects of my invention will be apparent or will be specifically pointed out in the description forming a part of this specification, but I do not limit myself to the embodiment of my in vention herein described, as various forms may be adopted within the scope of the claims.

In the drawing, illustrating a preferred embodiment of my invention, Figure 1 is a longitudinal sectional view, partly in elevation, of my invention.

Figure 2 is a cross sectional view taken in a plane indicated by the line 2-2 in Figure 1.

An envelope 1 is so shaped as to have a hemispherical end portion 2 and a cylindrical portion 3. Sealed to the open end of the cylindrical portion is a reentrant stem 4, through which are sealed cathode leads 5-5. The envelope is preferably molded from borosilicate or other heat resistant glass.

A cathode 6, in the form of a coiled ribbon filament, preferably of oxide coated refractory metal, is welded to the upper ends of the cathode leads. This cathode is relatively compact, capable of supplying high electron currents, and is mounted substantially at the center of the hemispherical portion.

A bell shaped anode 8 is also formed with a hemispherical anode portion 9 and a cylindrical anode portion 10, and is supported by the riveted end 11 of an anode lead 12 fused through the extreme end of the envelope at an anode seal 13.

This anode seal is protected by the customary cap 14, held in place by cement l5 and electrically connected to the anode lead by a weld 16.

The anode lead 12 is customarily made of tungsten, and I prefer to form the entire anode from nickel, tungsten or tantalum; but, in any event, I provide the entire exterior surface 17 with a high polish.

The surfaces of the anode and of the adjacent portions of the envelope are substantially concentric, the only deviations being the normal small changes of shape inherent in machinemolded bulbs. All portions of the anode will then be substantially equidistant from the surrounding envelope surfaces, and this distance is preferably made substantially equal to the mean free path of the contained mercury vapon Inasmuch as the two hemispherical portions are concentric, the cathode will be located at their common center.

I also prefer to make the cylindrical portion 10 of the anode extend well below the cathode, usually a distance equal to the radius of the hemispherical portion of the anode.

After the device has been assembled as described, a few drops of mercury are inserted and the tube is processed in accordance with approved methods.

When sealed from the pumps, the tube is provided with a condensing base 18 to regulate the vapor pressure, as described in my co-pending application, Serial No. 607,297, dated April 25, 1932. This base will be of an extent sufiicient to provide cooling to a temperature necessary for the maintenance of the correct pressure during operation.

The base 18 may be supplied with a screw thread 19 carrying a center contact 20, or may be equipped with other contact means as desired.

In operation, the device as above described has shown remarkable economies in cathode current consumption. As an example, one such tube having dimensions of five inches in length by one and one-half inches in diameter, has carried an eight ampere peak load under continuous operation with a cathode current consumption of only 14 watts. I prefer to operate the device at 3 watts cathode consumption per ampere output, whereas most previous rectifiers do not show better efiiciencies than fifty watts cathode consumption per ampere.

I at present believe this efficient operation to be due to the following facts:

There is a space 21, uniform in thickness, surrounding top and sides of the anode. This space contains no ionized vapor, as its thickness is substantially equal to the mean free path of the mercury vapor and, therefore, is an effective heat insulator.

The polished surface 17 on the exterior of the anode greatly reduces heat radiation.

The coiled cathode gives oiT maximum emission with a minimum of radiating surface, and is located to receive radiant heat from itself when reflected back from the interior of the anode.

The bell shaped anode is at the highest point in the tube, and the heat generated-by ionization is carried by convection from the glow region in the neighborhood of the mouth of the bell to the. interior of the bell, where it aids in, heating the.

cathode. The actual heat generated in the gas by the impact ionization is thus put toworkto help, heat the filament.

Just which one fact or combination of facts is the most important in raising theefiiciency as described, I am unable to tell at the present time, but the results as recited have been-.deter-' mined by careful experimentation.

I claim:

1. In combination, a mercury vapor rectifier comprising an envelope having a hemispherical a hemispherical end portion contained in said envelope, the end portions of said anode and said envelope being closely adjacent and concentric, and a coiled ribbon filament located substantially at the common center of said hemispherical portions.

3. In combination, a mercury vapor rectifier comprising an envelope having a hemispherical end portion, an-anode having a hemispherical end portion, all opposing portions of said anode and, envelope being concentric, and a cathode concentrated substantially at the common center of said hemispherical portions, said anode being positioned closer to the envelope than one quarter ofthe-clistance between said envelope and said cathode.

4. In combination, amercury vapor rectifier comprising an envelope having a hemispherical end portion, an anode having a hemispherical end portion, all said portions of said anode and envelope-being concentric; and a cathode concentrated' substantially at the common center of said hemispherical portions.

5. Incombination, a mercury vapor rectifier I comprising an envelope'having a cylindrical portion and a hemispherical end portion, an anode having a cylindrical portion and a hemispherical end portion, all said'portions-of said-anode and envelope beingconcentric andspacedapart at a distancesubstantially equal to themean free path of the mercury vapor.

RALPH M. HEINTZ

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