US3353037A - Apparatus for separately adjusting the vapor pressures of two or more substances in a common vapor chamber - Google Patents

Description

Nov. 14, 1967 A.JESTER ETAL 3,353,037 APPARATUS FOR SEPARATELY ADJUSTING THE VAPOR PRESSURES OF TWO OR MORE SUBSTANCES IN A COMMON VAPOR CHAMBER Filed May 11, .1964

United States Patent 3,353,037 APPARATUS FOR SEPARATELY ADJUSTING THE VAPOR PRESSURES OF TWO OR MORE SUB- STANCES IN A COMMON VAPOR CHAMBER Alfred Jester, Speyer, Reinhart Langpape, Mannheim, and Josef Bohdansky, Altenbach, Odenwald, Germany, assignors to Brown, Boveri & Cie., Aktiengesellschaft, Mannheim, Kafertal, Germany, a corporation of Germany Filed May 11, 1964, Ser. No. 366,348 4 Claims. (Cl. 310-4) Our invention relates to method and apparatus for separately adjusting the vapor pressures of two or more substances in a common vapor chamber.

Electronic components that exhibit gas discharge phenomena, for example thermionic converters such as thermodiodes of the type described and illustrated in Patents No. 2,980,819 and No. 3,054,914, are required to be filled with substances of varying partial vapor pressures simultaneously. Thermodiodes of this type serve to transform directly into electricity heat energy that is added thereto. They include an emitter for emitting charge carriers and a collector for receiving the same. The energy required for discharging these charge carriers from the emitter is dependent upon the vapor pressures of the specific gaseous substances in the discharge chamber in addition to the temperature. These substances reduce the work necessary to effect the discharge and produce a small discharge voltage. It is Well known that the element cesium is particularly well suited for this purpose. These qualities are improved by adding predetermined amounts of cesium fluoride. The advantageous cooperation of both materials is optimum at a rather specific ratio of the mixture, that is at a specific partial pressure ratio. Since the partial pressures depend upon the temperature appertaining to the solid or liquid phases of the material, however, it is necessary to make the temperatures of the various substances independently adjustable from one another in order to establish or regulate these partial pressures. In the case discussed hereinabove, for example, the temperature of the cesium fluoride is much higher than the temperature of the cesium.

It is an object of our invention to provide a method and an apparatus employing such a method in which the different partial pressures can be adjusted independently from one another by the simplest and least costly means.

To this end and according to a feature of our invention, each of the substances in the nongaseous, i.e. liquid or solid phase, is held available in separate receptacles communicating with the vapor chamber, and the temperature of each of the receptacles is adjusted according to the vapor pressure.

Other features which are considered as characteristic for the invention are set forth in the appended claims.

Although the invention has been illustrated and described as a method and apparatus for separately adjust ing the vapor pressure of two or more substances in a common vapor chamber, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.

The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description when read in connection with the accompanying drawings in which:

FIGS. 1 and 2 are diagrammatic cross-sectional views of diflierent embodiments of the apparatus constructed in accordance with our invention and with which the method of our invention is carried out.

Referring now to the drawings and particularly to FIG. 1, there is shown a gas-discharge chamber 5 of a thermodiode or similar gas-discharge device. The gas-discharge chamber 5 is in communication with a tubular receptacle 1 and an annular receptacle 2 through the openings 4 and 6 respectively. Receptacle 1 contains cesium and the receptacle 2 contains cesium fluoride, both of which are thermally volatile, i.e. vaporize upon suitable heating. The materials in the receptacles diffuse out of their respective receptacles into the gas chamber 5 in relation to their temperature.

Our invention thus permits another great dilficutly of the known apparatuses and methods to be overcome. As is well known, only that substance which has the lower temperature is in thermal equilibrium with its vapor. The other substance with the higher temperature diffuses continuously from the common gas chamber into the cooler receptacle of the other substance Where it condenses. In order to minimize the steady loss of the high temperature substance, the adjustment of the vapor pressure differences must be kept as small as possible by inserting a choke member therebetween.

In accordance with our invention, the receptacle 1, containing the cesium heated to a relatively lower temperature, due to cooling provided by a cooling coil 7, communicates with the vapor chamber 5 of the thermodiode through a very small opening 4. On the other hand, the warmer receptacle 2 containing cesium fluoride is con- ,nected with the same vapor chamber through the substantially larger opening 6. Due to the very small opening 4, only small amounts of the higher temperature cesium fluoride pass into the cesium storage receptacle 1, so that as a result of the choking action effected by the small opening 4 the desired ratio of partial vapor pressures is not disturbed. The opening 4 is large enough, however, to permit predetermined amounts of the colder cesium to pass through. It has been found to be advantageous to provide an opening 4 having a cross-sectional area on the order of magnitude of cm.

The arrangement of the supply receptacles 1 and 2 in accordance with our invention, as shown in FIG. 1, permits a temperature difierence to be maintained in the simplest manner due to heat conduction through the tube 3. The material of which the vaporizing device, and more particularly the tube 3, consists, is stainless steel which is resistant to the chemically aggressive cesium and is a relatively good heat conductor. Heat is furnished by the highly heated thermodiode 5 and is conducted through the tube 3 to the receptacles 1 and 2. Naturally, a higher temperature is produced in the cesium fluoride receptacle 2, which is spaced only slightly from the thermodiode 5, than in the substantially farther removed cesium receptacle 1. By supplemental cooling of the tube 3 instead of or in addition to cooling receptacle 2 with the cooling coil 7, the temperature difference between both receptacles 1 and 2 can be altered within specific limits.

In the embodiment illustrated in FIG. 2, the supply receptacles 1 and 2 are located in diflerent connecting tubes 8 and 9 respectively, of the thermodiode. Separate adjustment of the receptacle temperatures, such as by suitable cooling coils, is consequently readily possible with this embodiment.

Instead of the very small opening 4, the choke action necessary for minimizing the aforementioned gas balancing or equilibrium, produced by the flow of the higher temperature cesium fluoride vapor into the lower temperature cesium receptacle, is effected by a porous membrane or diaphragm of limited permeability consisting of glass or a similar silicon product, which covers the opening 4' as shown in FIG. 2. By using a membrane of this another. The partial vapor pressures of each substance thus remain the same throughout the entire vapor chamber.

It is, of course, self-evident that the method of our invention can also be used for more than two substances accordingly.

We claim: 1. Apparatus for separately regulating the vapor pressures of at least two thermally volatile substances in a chamber, said apparatus comprising at least two receptacles communicating with the chamber, said receptacles respectively containing the substances in non-vaporous phase, means for heating the substances in said receptacles to their volatilizing temperatures, and means for adjusting the temperature in each of said receptacles in accordance with the vapor pressure of the respective substance, the receptacle of relatively lower temperature communicating with the chamber through an opening having a much smaller cross section than the opening through which the higher temperature receptacle com- .municates with the chamber, whereby the higher temperature vapor in the chamber is choked from entering the lower temperature receptacle.

2. Apparatus according to claim 1, wherein the opening between said lower temperature receptacle and the chamber has a cross-sectional area on the order of magnitude of $6 cm.

3. Apparatus for separately regulating the vapor pressures of at least two thermally volatile substances in a chamber, said apparatus comprising a connecting tube extending from the chamber and formed with at least two receptacles located at different distances from and communicating with the chamber, said receptacles respectively containing the substances in non-vaporous phase, means for heating the substances in said receptacles to their volatilizing temperatures, and means for adjusting the temperature in each of said receptacles in accordance with the vapor pressure of the respective substance, the receptacle of relatively lower temperature communicating with the chamber through an opening having a much smaller cross section than the opening through which the higher temperature receptacle communicates with the chamber, whereby the higher temperature vapor in the chamber is choked from entering the lower temperature receptacle.

4. Apparatus for separately regulating the vapor pressures of at least two thermally volatile substances in a chamber, said apparatus comprising at least two connecting tubes extending from the chamber, each formed with a receptacle communicating with the chamber, said receptacles respectively containing the substances in nonvaporous phase, means for heating the substances in said receptacles to their volatilizing temperatures, and means for adjusting the temperature in each of said receptacles in accordance with the vapor pressure of the respective substance, the receptacle of relatively lower temperature communicating with the chamber through an opening having a much smaller cross section than the opening through which the higher temperature receptacle communicates with the chamber, whereby the higher temperature vapor in the chamber is choked from entering the lower temperature receptacle.

References Cited UNITED STATES PATENTS 3,215,868 11/1965 Pidd 310-4 MILTON O. HIRSHFIELD, Primary Examiner.

LW. GIBBS, ]R., Examiner.

Claims (1)

1. APPARATUS FOR SEPARATELY REGULATING THE VAPOR PRESSURES OF AT LEAST TWO THERMALLY VOLATILE SUBSTANCES IN A CHAMBER, SAID APPARATUS COMPRISING AT LEAST TWO RECEPTACLES COMMUNICATING WITH THE CHAMBER, SAID RECEPTACLES RESPECTIVELY CONTAINING THE SUBSTANCES IN NON-VAPOROUS PHASE, MEANS FOR HEATING THE SUBSTANCES IN SAID RECEPTACLES TO THEIR VOLATILIZING TEMPERATURES, AND MEANS FOR ADJUSTING THE TEMPERATURE IN EACH OF SAID RECEPTACLES IN ACCORDANCE WITH THE VAPOR PRESSURE OF THE RESPECTIVE SUBSTANCE, THE RECEPTACLE OF RELATIVELY LOWER TEMPERATURE COMMUNICATING WITH THE CHAMBER THROUGH AN OPENING HAVING A MUCH SMALLER CROSS SECTION THAN THE OPENING THROUGH WHICH THE HIGHER TEMPERATURE RECEPTACLE COMMUNICATES WITH THE CHAMBER, WHEREBY THE HIGHER TEMPERATURE VAPOR IN THE CHAMBER IS CHOKED FROM ENTERING THE LOWER TEMPERATURE RECEPTACLE.

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