JPH0560467A - Heat beam-condensing type electric furnace - Google Patents

Abstract

PURPOSE:To obtain a heat condensing type electric furnace capable of obtaining a sudden temperature gradient or an arbitrary temperature gradient by a method wherein an evacuating passage, communicating with a doughnut type heat-condensing space, is opened on the main body of heat condensing element and a seal mechanism is provided between the outer peripheral wall of a furnace tube and the inner peripheral wall of the heat condensing element. CONSTITUTION:A heat condensing element 1 is constituted of the main body 10 of the heat condensing element, forming a doughnut type heat-condensing space 12, and a heat generating body 2, arranged annularly in the doughnut type heat-condensing space near the recessed surface type heat-condensing surface. An evacuating passage 13, communicated with the doughnut type heat-condensing space, is opened on the main body 10 of the heat condensing element while seal mechanisms 13, 14 are provided between the outer peripheral wall of a furnace tube and the inner peripheral wall of the heat condensing element. A plurality of heat condensing elements are stacked in the axial direction of the furnace to obtain a multi-layer type electric furnace and the evacuating passage 13 is opened on at least one piece of the heat condensing element 1 while the doughnut type heat-condensing spaces 12 of respective heat condensing elements are made to communicate with each other spatially.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat concentrating electric furnace, and more particularly, to a completely new free image furnace capable of producing from a rapid temperature gradient to an arbitrary temperature gradient, and in particular, the object to be heated has physical properties. The present invention relates to an electric furnace suitable for a field that requires treatment in a steep temperature gradient.

[0002]

2. Description of the Related Art In a conventional multi-layer furnace, the heating element is made as thin as possible and Zr is placed outside the heating element.
There is known a horizontal Bridgman furnace in which a ceramic such as O ₂ is arranged, a cooling body is further placed outside thereof to form a heating element, and an electric furnace having a multilayer structure of the heating element is placed horizontally.

However, in this method, the heating elements interfere with each other due to heat and the maximum temperature is 40 ° C./cm, so that a steep temperature gradient cannot be obtained. Therefore, when a material with high viscosity was made into a single crystal, bubbles could not be obtained and it was not possible to make a high quality single crystal, and when synthesizing a single crystal by the solvent method, the solvent was placed inside the single crystal. It was a cause of deterioration of quality and characteristics.

A light converging electric furnace is also known, which is a type in which the heat of the lamp at the first focal point is collected and heated to the second focal point on the converging surface of the spheroid. Is large and the size of the object to be heated is as small as about 10 mmφ, so that it can be used only for limited substances, and a multilayer structure is impossible.

The present invention has been made to solve the above-mentioned problems of the prior art, and its object is to provide an electric furnace capable of obtaining a sharp temperature gradient or an arbitrary temperature gradient.

[0006]

The present inventor has conducted extensive studies on a new free image furnace in order to solve the above problems. As a result, in order to obtain a steep temperature gradient, a heat condensing type must be used, and the heat density must be increased unless the heating element is made as thin as possible, and the heat condensing part and the heating element part must be evacuated. It was found that the loss of heat convection increased.

Specifically, the heat density can be increased by reducing the thickness of the heat condensing body as much as possible and further condensing the heat on the one surface by the condensing surface, so that the heat generating body and the heat condensing surface are close to each other. However, if gas is present there, heat loss due to high-velocity gas convection will increase, and the temperature inside the electric furnace will not rise even if the power supplied to the heating element is increased. We have found an electric furnace that can achieve a maximum temperature gradient of 100 ° C / cm by constructing a structure that allows a vacuum to be drawn between the heating elements and reducing heat loss due to thermal convection. Further, the inventors have found an epoch-making universal electric furnace in which, if this temperature gradient can be obtained, the heat condensing element can be multi-layered and a user can freely create an arbitrary temperature gradient and temperature distribution.

That is, the present invention is an electric furnace having a furnace core tube for accommodating an object to be heated and a heat concentrating element arranged in a ring shape around the furnace core tube. Is a heat condensing element body in which a concave condensing surface extends in a donut shape around the furnace core tube to form a donut condensing space, and a concave condensing surface in the donut condensing space. A heating element arranged in a ring shape close to the heat condensing element, and a vacuum evacuation path communicating with the donut-shaped condensing space is opened in the body of the heat condensing element and the donut-shaped space of the heat condensing element. A heat concentrating electric furnace is characterized in that a sealing mechanism is provided between an outer peripheral wall of a furnace core tube and an inner peripheral wall of a heat condensing element so that the inside can be made into a vacuum state.

Another aspect of the present invention is a multilayer electric furnace in which a plurality of heat concentrating elements are stacked in a multilayer structure in the axial direction of the furnace, and at least one heat concentrating element has a passage for evacuation. Is opened, and the donut-shaped condensing space of each heat condensing element is spatially connected to each other.

The present invention will be described in more detail below with reference to the drawings.

[0011]

Example 1

This example is an example of an electric furnace of the type having one heat condensing element, and FIG. 1 is an overall view thereof. In FIG. 1, 1 is a heat collector, 2 is a heating element, 3 is a vacuum pump, 4 is a vacuum hose, 5 is a furnace core tube, 6 is a drive motor section, 7 is a moving shaft, 8 is a fishing line, and 9 is The gantry, 10 is a crucible, and 11 is a sample. Heat treatment can be performed by moving the sample 11.

FIG. 2 is a longitudinal sectional view of a one-layer type electric furnace in which one heat condensing element is enlarged, FIG. 3 is a plan view thereof, and FIG. 4 is a plan view of a state in which a heating element is arranged. The heat condensing element 1 is
A plurality of main body blocks are stacked in a ring shape, that is, in a ring shape around the furnace core tube 5 so that the furnace core tube 5 can penetrate in the center, and a concave condensing surface ₁₁ is arranged around the furnace core tube 5. a thermal focusing elements body 1 ₀ structure to form a donut-shaped condenser space 1 ₂ extending in a donut shape, heating elements arranged in a ring shape in proximity to the concave converging surface of the donut-shaped condenser space Two
It consists of

[0014] As shown in FIGS. 1 and 2, the heat condensing element body 1 _0, the furnace core tube 5 toward the vacuum leading path 1 ₃ leading into a donut-shaped current mirror space 1 ₂ is opened .. This passage 1 ₃
Is a vacuum pump 3 via a vacuum hose 4 as shown in FIG.
Connected to. Walls and thermal condensing element body 1 ₀ furnace core tube 5
Since a sealing O-ring is provided between and, the donut-shaped light collecting space 1 ₂ can be made into a vacuum state via the evacuation passage 1 ₃ . Of course, sealing O-ring 13 to hot condensing element body 1 ₀ block is provided throughout. Incidentally, the heat condensing element body 1 ₀ showed a structure of assembling a plurality of blocks may be integrated.

The heating element 2 is held in a coil shape by the ceramic holder 12 and passes through the electrode block 18 and the electrode 19.
And is connected to the electrode terminal 17. Thirteen
Is an O-ring for sealing. Further, the electrode portion has a hermetically sealed structure using the O-ring 13, and the O-ring 13 also serves as insulation. As shown in FIG. 4 and FIG. 6, water cooling jigs 15 are attached at four positions in order to cool the heat condensing element with water, and water entering from the inner pipe passes through the hole 16 through the outer pipe. It enters from the outer pipe of the second water cooling jig, passes through the inner pipe, and is discharged to the outside. Reference numeral 20 is an O-ring for sealing.

In FIG. 7, reference numeral 25 is a thermocouple section, which senses the temperature. The thermocouple part has a hermetically sealed structure. Thermocouple, it is inserted from obliquely heat focusing elements 1 _0, O
The groove of the ring is positioned so as not to get in the way, and the thermocouple 25 is insulated by the alumina glass 21, and the insulator part 22 having two holes, the silicone rubber 23, and the tightening screw 2
It can be sealed at 4.

According to this one-layer type electric furnace, the heat collecting type
Since the heat condenser and the heating element are evacuated, a sharp temperature gradient can be created.

[0018]

[Embodiment 2] This embodiment is an example of a multi-layer electric furnace in which a plurality of heat condensing elements are stacked in a multilayer structure in the axial direction of the furnace, FIG. 8 is an overall view thereof, and FIG. 9 is a heat condensing element. It is the longitudinal cross-sectional view which expanded. In the case of the drawing, only a part of the multilayer heat collecting elements is shown. The structure is basically the same as that of the first embodiment, but the structure for vacuuming is different.

[0019] That is, among the multi-layered heat focusing elements 1, (in the illustrated case, the bottom of the heat focusing elements) at least one thermal condensing element 1 with a vacuum leading path 1 ₃ is opened The donut-shaped condensing space 1 _{2 of} each heat condensing element spatially communicates with each other. For communicating As shown in the figure, the outer peripheral wall of the furnace core tube 5, a gap between the heat condensing element body 1 _0, except for the heat focusing elements in the bottom is formed, the heat focusing elements It is preferable that the doughnut-shaped spaces 1 ₂ are spatially connected to each other.

[0020] When assembling the heat focusing elements 1 of the multi-layer at the appropriate number, at least one thermal condensing element 1 (in the illustrated case, the bottom of the heat focusing elements) opening the vacuum leading path 1 ₃ If the above-mentioned one is used, a multilayer electric furnace in which a desired number of heat condensing elements are laminated can be constructed by simply laminating the remaining heat condensing elements thereon. A multi-layer type can be easily formed simply by stacking heat condensing element units having the same structure. Moreover, since it is a unit type, the degree of vacuum can be easily maintained.

According to this multi-layer type electric furnace, it is possible to create a sharp temperature gradient and also to create an arbitrary temperature gradient by using a plurality of heat condensing elements.

In each of the one-layer type and multi-layer type electric furnaces, the entire electric furnace (ie, the heat collecting element, the furnace core tube) is used as a vacuum means other than vacuuming only the donut-shaped space of the heat collecting element. , Crucible, sample, etc.) can be considered as a vacuum structure, but such a vacuum means requires the number of electric furnaces to be prepared according to the number of heat condensing elements (the number of laminated layers). , Uneconomical.

[0023]

As described in detail above, according to the present invention,
A maximum temperature gradient of 100 ° C / cm can be obtained due to the heat condensing effect of the heat condensing element and the effect of preventing heat convection due to the vacuum of the heating element part. Furthermore, by forming multiple layers, an arbitrary temperature distribution can be created. It is possible to provide a universal electric furnace capable of performing the above.

Therefore, conventionally, it was necessary to manufacture the electric furnaces corresponding to the respective purposes according to the number of purposes, but according to the present invention, one electric furnace is sufficient, and in particular, Suitable for use in.

(1) When growing a single crystal having high viscosity by the Bridgman method, the maximum gradient of this electric furnace is 10
Since it is 0 ° C / cm, a high quality single crystal can be grown. (2) In the case of a substance having a transition point at a high temperature, the crystal structure in a high temperature state can be brought to room temperature by raising the temperature of the entire substance to the transition point or more and cooling the whole substance at once. (3) Conventionally, when growing a single crystal by the Bridgman method, the sample was moved or the electric furnace was moved.
According to the present invention, it is possible to move the temperature distribution without mechanically driving (moving the sample and the electric furnace) by independently controlling the multi-layered heat condensing element and program-controlling each.

[Brief description of drawings]

FIG. 1 is an overall view of a heat concentrating electric furnace provided with one heat condensing element.

FIG. 2 is an enlarged vertical sectional view of a part of the heat condensing element.

FIG. 3 is a plan view of a heat condensing element.

FIG. 4 is a plan view of a heat condensing element, showing a state in which heating elements are arranged.

FIG. 5 is a plan view showing an electrode portion of a heating element of the heat condensing element.

FIG. 6 is a plan view showing a water cooling unit of the heat condensing element.

FIG. 7 is a diagram showing a thermocouple portion of a heat condensing element.

FIG. 8 is an overall view of a heat concentrating electric furnace in which a plurality of heat concentrating elements are stacked in multiple layers in the furnace axis direction.

FIG. 9 is a diagram showing a thermocouple portion of a heat collecting element in a multilayer heat collecting electric furnace.

[Explanation of symbols]

1 heat condensing element 1 ₀ heat condensing element main body 1 ₁ concave condensing surface 1 ₂ donut-shaped heat condensing space 1 ₃ vacuum passage 2 heating element 3 vacuum pump 4 vacuum hose 5 furnace core tube 6 drive motor section 7 Moving shaft 8 Fishing line 9 Stand 10 Crucible 11 Sample 12 Heating element holding ceramic 13 Sealing O-ring 14 Sealing O-ring 15 Water-cooling jig 16 Holes 17 Electrode terminal 18 Electrode block 19 Electrode 20 Sealing O-ring 21 Alumina insulator 22 Insulator 23 Silicon rubber 24 Tightening screw 25 Thermocouple

Claims (4)

[Claims] 1. An electric furnace comprising: a furnace core tube for accommodating an object to be heated; and a heat collecting element arranged in a ring shape around the furnace core tube, wherein the heat collecting element has a concave shape. The light condensing surface of the thermal condensing element body extending in a donut shape around the furnace core tube to form a donut-shaped condensing space, and a heat condensing surface close to the concave condensing surface in the donut-shaped condensing space. It consists of a ring-shaped heating element, and the heat condensing element body has an opening for vacuuming that leads to the donut-shaped condensing space, and the inside of the donut-shaped space of the heat condensing element is in a vacuum state. The heat concentrating electric furnace is characterized in that a sealing mechanism is provided between the outer peripheral wall of the furnace core tube and the inner peripheral wall of the heat concentrating element so that the above can be achieved. 2. A multi-layer type electric furnace in which a plurality of heat condensing elements are stacked in a multi-layer structure in the axial direction of the furnace, and at least 1.
The heat-collecting element according to claim 1, wherein a vacuum passage is opened in each of the heat collecting elements, and the donut-shaped light collecting spaces of the respective heat collecting elements are spatially connected to each other. Concentrating electric furnace. 3. A furnace core tube outer peripheral wall and each heat condensing element inner peripheral wall
A gap is formed between the heat condensing element and the heat condensing element (excluding the heat concentrating element in which the evacuation passage is opened), and the donut-shaped spaces of the respective heat condensing elements are in spatial communication with each other. The heat concentrating electric furnace described. 4. The heat concentrating electric furnace according to claim 1, 2 or 3, wherein a cooling passage is provided in the heat concentrating element body.