WO2005038373A1 - High-pressure heat treatment furnace - Google Patents

Abstract

A high-pressure heat treatment furnace, comprising a pressure vessel having a furnace container and a furnace cover closing the furnace container and allowing an internal pressure to be controlled, heat-insulating walls installed in the pressure vessel, opened oppositely to the furnace cover, and forming a heating chamber for storing a treated material therein, a heat-insulating cover driven to open and close the opening part of the heat-insulating wall, a heater installed in the heating chamber to heat the treated material, and a plurality of cooling fins installed on the inner surface of the furnace cover to cool gases in the pressure vessel.

Description

 Specification

 High pressure heat treatment furnace

 Background of the Invention

 [0001] TECHNICAL FIELD OF THE INVENTION

 [0002] The present invention relates to a high-pressure heat treatment furnace for heat-treating metals such as cemented carbides, ceramics, composite materials, and the like at a high pressure of normal pressure IMPaG or more, and more specifically, a high-pressure heat treatment furnace capable of rapidly cooling the inside of the furnace. About.

 Description of related technology

 [0003] In a high-pressure heat treatment furnace in which cemented carbide, ceramics, etc. are heat-treated at a high pressure higher than the normal pressure IMPaG, in order to shorten the cycle time and improve the quality of the treated product, is it necessary to reduce the furnace cooling time? Is an important issue. FIG. 1 is a schematic configuration diagram of a conventional general high-pressure heat treatment furnace as disclosed in Patent Document 1 below, for example. In FIG. 1, reference numeral 3 denotes a pressure vessel composed of a furnace vessel 1 and a furnace lid 2 that closes both ends of the furnace vessel 1. Jackets 4 and 5 are provided on the outer periphery of the furnace vessel 1 and outside the furnace lid, respectively. The cooling water is allowed to flow through the inside. Inside the pressure vessel 3, a hollow cylindrical heat insulating wall 6 having openings at both ends is provided, and an inner case 17 is disposed therein, and the object 7 to be heated is accommodated therein. Reference numeral 8 denotes a heat insulating cover (bang) that opens and closes the opening of the heat insulating wall 6, and is driven to open and close by a cylinder 9 provided outside the furnace cover 2. Reference numeral 10 denotes a heater for heating the object 7 to be heated, and a heating chamber 11 is formed inside the heat insulating wall 6. In addition, as shown in FIG. 2, instead of providing a jacket for cooling water on the outer periphery of the furnace vessel 1, a water cooling tube 12 for circulating cooling water inside the furnace vessel 1 may be provided. 1 and 2, reference numeral 16 denotes a space formed between the pressure vessel 3 and the heat insulating wall 6.

[0004] In this heat treatment furnace, after the object 7 is charged into the heating chamber 11 and the heat insulating wall 8 is closed, an atmosphere gas is introduced into the heating chamber 11 and the object 7 is gasified by the heater 10. After heating and sintering in an atmosphere, the processing object 11 is taken out after the atmosphere gas in the heating chamber 11 and the processing object 7 are sufficiently cooled. [0005] FIG. 3 is a diagram showing a state of a change in a furnace temperature (heating chamber temperature) during operation in the above-described heat treatment furnace. As shown in this figure, at the start of operation, the heater is energized at! Jt to raise the temperature.

 0

 Starting from time t to time t and at a predetermined processing temperature (for example, 1500 ° C).

 1 2

 And heat treatment is performed. Then, at the time t when the process is completed, communication with the heater is performed.

 2

 The electricity is stopped and the process proceeds to the cooling process. In the cooling process, the heat-insulating lid 8 is closed at first, and the heat-insulating lid 8 is opened when the temperature in the furnace decreases to a predetermined temperature T. The time at temperature T is t. As a result, a natural difference occurs due to the temperature difference between the heating chamber 11 and the space 16.

 Three

 A flow is generated, and the gas 18 flowing out of the heating chamber 11 is cooled by exchanging heat with the inner surface of the water-cooled furnace wall, thereby promoting the cooling of the furnace.

 FIG. 4 shows a heat treatment furnace disclosed in Patent Document 2. This heat treatment furnace is characterized in that it includes an internal circulation fan 19, a motor 20 for driving the internal circulation fan 19 to rotate, and a circulation gas guide plate 21. In the cooling step, as in the case of the heat treatment furnace described above, the heat-insulating lid 8 is initially closed, and when the furnace temperature drops to a predetermined temperature, the heat-insulating lid 8 is opened. The hot gas 18 in the heating chamber 11 is sucked from one opening (right side in the figure) of the heating chamber 11 and circulated to the heating chamber 11 from the opening on the opposite side (left side in the figure) by the circulation gas guide plate 21. Has become. As a result, forced gas convection is generated, heat exchange with the inner surface of the pressure vessel 3 is promoted, and the cooling capacity of the furnace is improved.

 Patent Document 1: Japanese Patent Application Laid-Open No. Hei 4-26726 (FIG. 7)

 Patent Document 2: Japanese Patent Publication No. 62-55529 (Fig. 1)

 [0008] However, the above-described cooling method in the conventional high-pressure heat treatment furnace has various problems as follows.

 (1) In the method in which the jackets 4 and 5 are provided on the furnace vessel 1 and the furnace lid 2 as shown in FIG. 1, since the heat transfer area is limited to the inner wall area of the pressure vessel 3, the cooling area is sufficient. Low cooling capacity. In addition, since the wall thickness of the pressure vessel 3 is thick enough to withstand high pressure, it is difficult to sufficiently cool the inner wall of the pressure vessel 3 even with water cooling from the outer wall of the pressure vessel 3. For this reason, the cooling capacity is restricted.

[0010] (2) In the method in which the water-cooled tube 12 is provided on the inner wall of the furnace vessel 2 as shown in Fig. 2, the water-cooled tube 12 itself is expensive, so that the cost burden is large and uneconomical. Also water It is necessary to increase the furnace diameter to secure the installation space for the cold tube 12. Further, there is a danger of water leak and gas leak from the water cooling tube 12. Furthermore, if the amount of flowing water decreases due to clogging of the water cooling tube 12 or the like, not only the cooling effect cannot be obtained, but also the water cooling tube 12 may be damaged.

[0011] (3) In the method in which the internal circulation fan 19, the motor 20, and the circulation gas plan inner plate 21 are provided in the pressure vessel 3 as shown in Fig. 4, the structure becomes complicated due to the addition of the fan and the motor. This will increase manufacturing costs. In addition, customer power supply equipment and running costs associated with power supply to the motor will increase. In addition, there is a risk of failure due to damage to bearings, etc., and maintenance costs also increase. In addition, depending on the wind pressure of the fan, there is a case where a light weight object cannot be processed. Furthermore, the motor capacity is limited by the installation space of the motor, and the cooling capacity is limited. Summary of the Invention

 The present invention has been made to solve the above-mentioned problems. That is, an object of the present invention is to provide an economical high-pressure heat treatment furnace that has a high cooling capacity, can shorten the cycle time, has a simple structure, and is economical.

[0013] To achieve the object of the present invention, according to the first invention, a pressure vessel having a furnace vessel and a furnace lid for closing the furnace vessel, and a pressure vessel provided in the pressure vessel, A heat-insulating wall that opens oppositely to form a heating chamber for accommodating the object to be processed, a heat-insulating lid that is driven to open and close the opening of the heat-insulating wall, and an object to be processed provided in the heating chamber. And a plurality of cooling fins provided on the inner surface of the furnace lid and cooling the gas in the pressure vessel.

[0014] According to the first invention, by providing a plurality of cooling fins for cooling gas flowing in the pressure vessel, the cooling area in the pressure vessel is greatly increased, and as a result, the cooling performance is improved. Therefore, the effect that the cycle time of the furnace can be shortened is obtained. In addition, since there are no moving parts, there is no need for electricity or gas, which has no cause for malfunction, and there is no problem with life. Therefore, it is excellent in energy saving and can be used semi-permanently. [0015] A second invention is a preferred embodiment of the first invention, wherein the cooling fin is connected to a cooling member cooled by a refrigerant.

[0016] According to the second aspect, since the cooling fins are provided so as to be connected to the cooling member cooled by the refrigerant, the structure is simple and the number of parts is small, so that the cost increases. It is minimal and economical.

[0017] A third invention is a preferred embodiment of the second invention, wherein the cooling member is attached to an inner wall surface of the container lid.

[0018] According to the third invention, by attaching the cooling member to the inner wall surface of the furnace lid, the cooling member can be installed simply by extending the furnace vessel length, and the design is easy. In addition, since the cooling fins are located near the position where the high-temperature gas is blown from the heating chamber, the cooling effect can be enhanced.

A fourth invention is a preferred embodiment of the second invention, wherein the cooling fin and the cooling member are integrally formed.

[0020] According to the fourth aspect, by forming the cooling fin and the cooling member integrally, it is possible to eliminate a gap generated at a connecting portion between the cooling fin and the cooling member. Thereby, the heat transfer between the cooling fins and the cooling member can be sufficiently ensured, and the cooling performance can be sufficiently exhibited.

A fifth invention is a preferred embodiment of the first invention, wherein each of the cooling fins has a slit for absorbing thermal expansion.

[0022] According to the fifth invention, each cooling fin has a slit for absorbing thermal expansion, so that deformation and breakage of the cooling fin can be prevented, and gas enters the slit. As a result, a vortex is generated in the gas flow, and the cooling efficiency is improved.

[0023] A sixth invention is a preferred embodiment of the first invention, wherein the cooling fin is made of a material having excellent thermal conductivity (aluminum, copper, or the like).

[0024] According to the sixth aspect, the cooling fin is made of a material having excellent thermal conductivity, so that the gas in the pressure vessel can be effectively cooled. As a result, the cooling performance is improved, and the cycle time of the furnace can be significantly reduced.

[0025] A seventh invention is a preferred embodiment of the first invention, wherein the cooling fin is oriented in a longitudinal direction of the fin in a direction along a gas flow.

[0026] According to the seventh invention, the longitudinal direction of the cooling fins is set in a direction along the gas flow. Thus, the natural convection can be smoothly performed without obstructing the gas flow, and the cooling performance can be improved.

 [0027] Other objects and advantageous features of the present invention will become apparent from the following description with reference to the accompanying drawings. Brief Description of Drawings

 FIG. 1 is a schematic configuration diagram of a conventional high-pressure heat treatment furnace.

 FIG. 2 is a schematic configuration diagram of another conventional high-pressure heat treatment furnace.

 FIG. 3 is a view showing a state of a change in a furnace temperature (heating chamber temperature) during operation in the high-pressure heat treatment furnaces of FIGS. 1 and 2.

 FIG. 4 is a schematic configuration diagram of another conventional high-pressure heat treatment furnace.

 FIG. 5 is a schematic configuration diagram of a high-pressure heat treatment furnace of the present invention.

 FIG. 6 is a view showing a state of a change in a furnace temperature (heating chamber temperature) during operation of the high-pressure heat treatment furnace of the present invention.

 Description of the preferred embodiment

Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to FIGS. 5 and 6.

FIG. 5 is a schematic configuration diagram showing an embodiment of the high-pressure heat treatment furnace of the present invention. In FIG. 5, reference numeral 3 denotes a pressure vessel composed of a hollow cylindrical furnace vessel 1 and a flat furnace lid 2 that closes both ends of the furnace vessel 1. The pressure vessel 3 is configured to control the internal pressure. Further, a jacket is provided on the outer periphery of the furnace vessel 1, and cooling water is circulated inside as a coolant to cool the furnace vessel 1.

Reference numeral 6 denotes a hollow cylindrical heat-insulating wall provided in the pressure vessel 3, in which an inner case 17 is disposed, and the object 7 to be heated is accommodated therein. Both ends of the heat insulating wall 6 have openings that open at positions facing the furnace wall 2. Reference numeral 8 denotes a heat-insulating lid (bang) for opening and closing the opening of the heat-insulating wall 6, which is driven to open and close by a cylinder 9 provided outside the furnace lid 2. Reference numeral 10 denotes a heater for heating the object 7 to be heated, and a heating chamber 11 is formed inside the heat insulating wall 6. Reference numeral 16 denotes a space formed between the pressure vessel 3 and the heat insulating wall 6. [0032] Reference numeral 13 denotes a cooling fin for cooling the gas 18 in the pressure vessel 3, and is connected to a cooling member 14 attached to the inner wall surface of the furnace lid 2. The cooling member 14 has a circular flat plate shape, and has a structure in which cooling water flows as a coolant inside. Further, the cooling member 14 has an opening 14a for passing the rod of the cylinder 9 in the center. The cooling fins 13 are in the shape of a rectangular flat plate, and are connected to each other at a predetermined interval perpendicular to one surface of the cooling member 14. For the cooling fins 13, a metal material having excellent heat conductivity is used. However, it is particularly preferable to use aluminum, copper, or the like having good heat conductivity. Since copper has higher thermal conductivity and lower linear expansion coefficient than aluminum, copper is more suitable as a material for cooling fins than aluminum.

 In the present embodiment, since the high-pressure heat treatment furnace is of a horizontal type, the gas 18 blown out from the heating chamber 11 flows in the direction of the arrow. Therefore, the cooling fins 18 are preferably set so that the direction along the direction in which the gas 18 flows, that is, the length direction (longitudinal direction) is oriented vertically. As a result, the natural convection can be smoothly performed without obstructing the flow of the gas 18, and it is possible to exert a good cooling performance.

 [0034] The cooling fins 13 may be provided with slits for absorbing thermal expansion. For example, the slit may be provided with a plurality of notches extending in the width direction (transverse direction) of the cooling fin 13 across the length direction (longitudinal direction) of the cooling fin 13. As a result, the deformation and breakage of the cooling fin can be prevented by absorbing the thermal stress, and the gas enters the slit to generate a vortex in the gas flow, thereby improving the cooling efficiency.

 In FIG. 5, the cooling member 14 is attached to the furnace lid 2. The cooling water introduced into the cooling member 14 configured as described above cools the cooling member 14 and is discharged. The cooling fins 13 connected to the cooling member 14 are cooled by the cooling member 14.

[0036] The cooling fins 13 and the cooling members 14 may be separately formed and then joined by welding or the like, but it is difficult to bring all the mating surfaces of the cooling fins 13 and the cooling members 14 into close contact with each other. It is conceivable that the cooling performance of the fins 13 cannot be sufficiently exhibited. Therefore, in order to eliminate a gap between the cooling fin 13 and the cooling member 14, it is preferable that both are integrally formed. As a result, a sufficient amount of heat transfer between the cooling fins 13 and the cooling member 14 can be secured. Next, the operation of the high-pressure heat treatment furnace of the present invention configured as described above will be described. FIG. 6 is a diagram showing a change in the furnace temperature (heating chamber temperature) during operation in the high-pressure heat treatment furnace of the present invention. The solid line indicates the temperature change according to the present invention, and the dashed line indicates the conventional high temperature of FIG. The temperature change by the pressure heat treatment furnace is shown. As shown in Fig. 6, at the operation start time t

 0 to start the temperature rise by energizing the heater.

 1 2

 The heat treatment is performed while maintaining the temperature (for example, 1500 ° C.). And when the process is completed

 At two points, power supply to the heater is stopped and the process moves to the cooling process. In the cooling step, the heat-insulating lid 8 is closed at first, and the heat-insulating lid 8 is opened when the temperature in the furnace decreases to a predetermined temperature T '. At this time, the high-temperature gas 18 in the heating chamber 11 blows out from the opening of the heat insulating wall 6 toward the space 16 and contacts the cooling fins 13. Since the cooling fins 13 are cooled by the cooling member 14, the temperature T 'when opening the opening / closing door should be set to a temperature higher than the opening temperature T of the heat insulating lid of the conventional high-pressure heat treatment furnace in FIG. Can be. As a result, it is possible to advance the time t ′ at which the heat-insulating lid is opened from the time t in FIG.

 3 3

 The gas 18 in contact with the cooling fins 13 exchanges heat with many of the cooling fins 13, convects in the pressure vessel 3 while being cooled, and is circulated from the opening of the heat insulating wall 6 to the heating chamber 11. You. The cooling fins 13 are provided in a large number in the pressure vessel, and the cooling area is greatly increased as compared with the conventional one, so that the cooling performance is high. As a result, as shown in FIG. 6, the cooling time can be significantly reduced, and the cycle time of the furnace can be shortened. For example, it is possible to reduce the cooling time by about half compared with the conventional case.

In the present invention, the following effects can be obtained in addition to the effects described above. In other words, since there are no moving parts in the furnace cooling mechanism, there are no factors that cause malfunctions, and there is no need for electricity or gas, and there is no problem with life. Therefore, it is excellent in energy saving and can be used semi-permanently. Further, since the cooling fins are provided so as to be connected to the cooling member 14 cooled by the refrigerant and the cooling member 14 is attached to the inner wall portion of the pressure vessel 3, a cooling method using a water cooling tube, a cooling method using a motor and a fan, etc. Since the structure is simpler and the number of parts is small, the cost increase is minimized. The cooling member 14 inside the furnace lid 2 By mounting on a wall, it can be installed simply by extending the length of the furnace vessel, facilitating design.

 [0040] In the above-described embodiment, the furnace lid 2 of the pressure vessel 3 is a flat plate, but may be a curved end plate. In this case, the side of the cooling member 14 facing the furnace lid 2 is formed according to the curved shape of the head plate.

 Further, in the above-described embodiment, the horizontal type sintering furnace has been described, but the present invention is naturally applicable to a vertical type sintering furnace.

Although the high-pressure heat treatment furnace of the present invention has been described with reference to a preferred embodiment, it will be understood that the scope of rights included in the present invention is not limited to this embodiment. On the contrary, the scope of the invention is intended to cover all improvements, modifications and equivalents included in the appended claims.

Claims

The scope of the claims  [1] a pressure vessel having a furnace vessel and a furnace lid for closing the furnace vessel,  A heat-insulating wall provided in the pressure vessel, opened to face the furnace lid, and forming a heating chamber for accommodating an object to be processed therein;  An insulating lid driven to open and close the opening of the insulating wall,  A heater provided in the heating chamber to heat the object to be processed;  And a plurality of cooling fins provided on the inner surface of the furnace lid for cooling gas in the pressure vessel.  [2] The high-pressure heat treatment furnace according to claim 1, wherein the cooling fin is connected to a cooling member cooled by a refrigerant. [3] The cooling member, wherein the cooling member is attached to an inner wall surface of the furnace lid. 2. The high-pressure heat treatment furnace according to 2. 4. The high-pressure heat treatment furnace according to claim 2, wherein the cooling fin and the cooling member are integrally formed. 5. The high-pressure heat treatment furnace according to claim 1, wherein each of the cooling fins has a slit for absorbing thermal expansion. 6. The high pressure heat treatment furnace according to claim 1, wherein the cooling fin is made of a material having excellent thermal conductivity.  7. The high-pressure heat treatment furnace according to claim 1, wherein the cooling fins are oriented in a longitudinal direction of the fins in a direction along a gas flow.