JPH01184269A - Molten metal holder for generating metal vapor - Google Patents

Abstract

PURPOSE:To prevent corrosion of the inner side face of an inside vessel which comes into contact with a molten metal without affecting thermal efficiency, etc., by providing projections which project in an aperture direction from the bottom to the inside vessel and providing a thermal resistance layer between an outside vessel and the bottom of the inside vessel. CONSTITUTION:The molten metal 2 in the inside vessel 3a is heated by an electron beam 1 in the central part 9 of the liquid surface thereof and is cooled in the part in contact with the inside vessel 3a, by which natural convection 7 is generated. The molten metal 2 flowing to the outside collides partly against the projections 11 and falls to generate the natural convection 7a. The other part advances and falls down to the side face of the inside vessel 3a and generates the natural convection 7b. Since the thermal resistor layer 12 is inserted between the inside vessel 3a and the outside vessel 3, the cooling in the bottom of the inside vessel 3a weakens and the circulation of the natural convection 7b on the outside of the projection 11 strengthens. The inflow of the high-temp. molten metal 2 from the natural convection 7a to the natural convection 7b, therefore, decreases. The progression of the corrosion of the inner side face of the inside vessel 3a is, therefore, prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a molten metal holding device for metal vapor generation in an isotope atomic laser concentrator.

(Prior technology) Isotope atomic laser concentrators require metal vapor generation by heating the metal by irradiating it with an electron beam, laser light, etc. to melt and evaporate the metal in order to create a metal vapor flux. equipment is provided. A conventional example of a molten metal holding device provided in this metal vapor generator will be explained with reference to FIG. That is, this molten metal holding device 10 is formed of an outer container 4 with excellent thermal conductivity and an inner container 3 with poor thermal conductivity that is provided in close contact with the inside of this outer container 4. The inner wall surface is provided with a coating layer 6 having corrosion resistance against high temperature molten metal. Further, inside the wall material of the external container 4, a tubular coolant channel 5 as a cooling mechanism is provided along the side and bottom surfaces of the external container 4.

When a target metal is stored in the internal container 3 of this molten metal holding device 10 and irradiated with the electron beam 1, the metal melts into molten metal 2, and when the electron beam 1 is further irradiated and heating continues. A metal vapor flux (not shown) is generated. Note that during the above heating operation, a coolant such as water is flowed into the coolant channel 5 to cool the outer container 4 and the inner container 3 so that they do not melt.In the molten metal holding device 10, the molten metal 2 is , the central part 9 of the liquid surface is heated by the electron beam 1, while the parts in contact with the side and bottom surfaces of the inner container 3 are cooled by the coolant. A pair of natural convection flows 7 that flow along the side and bottom surfaces of the liquid and return to the central portion 9 of the liquid surface. This natural convection 7
When this occurs, the area 8 near the liquid surface on the side surface of the inner container 3 directly receives the high temperature molten metal 2 from the central area 9 of the liquid surface, resulting in a locally high temperature, which causes corrosion or damage to progress easily. be. Therefore, if the heating of the molten metal 2 is suppressed in order to prevent the progress of corrosion in the portion 8 near the liquid surface of the molten metal 2, a sufficient metal vapor flux cannot be obtained. Furthermore, if the cooling of the internal container 4 is strengthened by improving the thermal conductivity of the internal container 3 and increasing the cooling efficiency for the same purpose, the loss of heat from the molten metal 2 will increase, and the There are problems such as a decrease in thermal efficiency.

The present invention has been made in order to solve the above-mentioned problems.The present invention has been made in order to solve the above-mentioned problems. It is an object of the present invention to provide a molten metal holding device for generating metal vapor that has a function of preventing corrosion of the inner surface.

The molten metal holding device for generating metal vapor according to the present invention includes a projection protruding from the bottom of the inner container toward the opening of the device, and a heat resistor layer between the outer container and the bottom of the inner container of the device. It is characterized by having the following.

(Function) The metal stored in the internal container of the molten metal holding device for generating metal vapor is heated by the electron beam and becomes molten metal. At this time, natural convection is generated by being divided into an inner side and an outer side of the protrusion due to the protrusion provided on the inner container. Furthermore, by providing a heat resistor layer, the cooling efficiency of the bottom part of the inner container is reduced, and the side parts are relatively cooled the most, so the circulation force of the natural convection on the outside is strengthened, and the cooling efficiency from the inside of the protrusion is increased. At the same time, the direct influence of the high temperature molten gold i+ on the area near the liquid surface is eliminated, and at the same time, natural convection is formed on the outside of the protrusion at a temperature lower than that on the inside, which prevents the progress of corrosion on the side of the device. be able to.

(Example) Hereinafter, the present invention will be described in detail with reference to the drawings. In addition,
The same parts as those of the conventional molten metal holding device for generating metal vapor described above are given the same reference numerals.

FIG. 1 is a side view of a molten metal holding device 2 for generating metal vapor, showing an embodiment of the present invention. The molten metal holding device indicated by 10A in the figure includes an outer container 4 having high thermal conductivity, an inner container 3a having a protrusion 11 provided in close contact with the outer container 4, and a bottom of the outer container 4 and the inner container 3a = 4. - a heat resistor layer 12 inserted between the outer container 4 and the inner container 31;

A metal is stored in this internal container 3a, and when the internal container 3a is cooled by flowing a coolant through the coolant channel 5 and heated by irradiating an electron beam 1 from an electron gun (not shown), the metal melts. The state becomes molten metal 2.

The central part 9 of the liquid surface of the molten metal 2 is heated by the electron beam 1, while the part in contact with the inner container 3a is cooled, so that a natural convection 7 is generated due to the temperature difference.

A part of the molten metal 2 flowing outward from the central part 9 of the liquid surface collides with the protrusion 11, descends along it, passes through the bottom part, and returns to the central part 9 of the liquid surface, creating a natural convection 7a. The other part advances to the side surface of the inner container 3a without colliding with the protrusion 11, descends along this and passes through the bottom part to the protrusion 11.
1, a natural convection 7b is generated that rises along the line 1. Inner container△
Because the heat resistor layer 12 is inserted between the outer containers 4, the cooling of the bottom of the inner container 3a is cut off and weakened to some extent, and the cooling of the side surfaces is relatively strongest, and the natural outside of the protrusion 11 is The circulation of convection 7b becomes stronger. Therefore, from the natural convection 7a above the protrusion 11, the natural convection 7a
The flow of high temperature molten metal 2 into b is reduced, and the temperature of natural convection 7b becomes lower than that of natural convection 7a. Therefore, the inner container 3a
Since the direct influence of the high-temperature molten metal 2 is moderated on the side surface, the progress of corrosion on the inner surface is prevented.The same parts as in FIG. It is something that A protrusion 14 is provided on the bottom surface of the corrosion-resistant container 13 along the opening. In this molten metal holding device 10B, the corrosion-resistant container 13 of the internal container 3 can be replaced when corrosion occurs in the protrusion 14, the portion 8 near the liquid surface, etc., so that the molten metal holding device 1
Can prevent 0B corrosion.

〔Effect of the invention〕

According to the present invention, the natural convection of the molten metal in the inner container is divided to reduce the influence of the high temperature molten metal on the inner surface of the container, which affects the amount of metal vapor flux generated and the thermal efficiency for generation. It becomes possible to prevent the progress of corrosion on the inner surface of the container due to natural convection.

[Brief explanation of the drawing]

FIGS. 1 and 2 are longitudinal sectional views showing respective embodiments of the present invention, and FIG. 3 is a longitudinal sectional view showing a conventional example. DESCRIPTION OF SYMBOLS 1... Electron beam, 2... Molten metal, cylindrical part capacity, 4-% o, a, 5... Coolant channel, 6... Coating layer, 7.7a,
7b... natural convection, 8... near flow surface, 9... center of liquid surface, 10, IOA, IOB... molten metal holding device, 1
1, 14...Protrusion, 12...Heat resistor layer,
13...Corrosion-resistant container agent Patent attorney Nori Chika Ken Yudo Ken Daishimaru

Claims (1)

[Claims] A molten metal for generating metal vapor, in which a metal is stored in an inner container, and an outer container having a cooling mechanism is closely arranged on the outer surface of the inner container, and the metal is heated and melted to generate metal vapor from the molten metal. A molten metal for metal vapor generation in the holding device, characterized in that the inner container is provided with a protrusion projecting from the bottom toward the opening, and a heat resistor layer is provided between the outer container and the bottom of the inner container. holding device.