Continuous heat treatment furnace

Abstract

To provide a continuous heat treatment furnace that can improve the problem of deteriorated sealing performance at the inlet and outlet of the heating chamber, which becomes hot. [Solution] The continuous heat treatment furnace 1 is provided with an inlet-side double door 55 on the inlet 11a side of the first heating chamber 11 and an outlet-side double door 57 on the outlet 11b side. The inlet-side double door 55 consists of an inlet-side insulated door 55A that closes the inlet 11a and an inlet-side sealing door 55B that is located outside the compartment 22 where the inlet-side insulated door 55A is provided and closes the opening 22a of the compartment 22. The outlet-side double door 57 consists of an outlet-side insulated door 57A that closes the outlet 11b and an outlet-side sealing door 57B that is located outside the compartment 23 where the outlet-side insulated door 57A is provided and closes the opening 23a of the compartment 23.

Description

Technical Field

[0001] This invention relates to a continuous heat treatment furnace having a plurality of treatment chambers along the conveyance direction of a workpiece to be treated.

Background Art

[0002] In a continuous heat treatment furnace for heat-treating workpieces such as steel and ceramics while sequentially conveying them in a furnace, a plurality of treatment chambers are provided along the conveyance direction, and opening / closing doors are provided at the inlet and outlet of each treatment chamber. From the viewpoint of maintaining the temperature, atmosphere, pressure, etc. of each treatment chamber, it is preferable that the opening / closing door can hermetically close the inlet or outlet.

[0003] To seal openings such as inlets and outlets using a door, it is necessary to use a sealing member (for example, a rubber O-ring). However, these sealing members have low heat resistance. Therefore, when sealing the opening of a heating chamber where processing is performed at high temperature, it is necessary to protect the sealing member from the heat from the furnace interior and the material, such as by water-cooling the peripheral portion of the sealing member. If the door cannot maintain the sealing performance, it becomes impossible to vary the atmosphere gas and pressure between chambers, which results in restrictions on the processing.

[0004] Incidentally, the following Patent Document 1 discloses a technique related to the present invention. In this Patent Document 1, when the processing in the heating chamber is completed and the door (valve body) separates from the furnace body (peripheral portion of the opening), it is disclosed that a heat shield plate is inserted into the gap generated between the door and the furnace body to protect the sealing member (packing). However, what is described in Cited Document 1 requires a certain amount of time to move the heat shield plate to a predetermined position after the door separation, and during that time, the packing is heated by the heat input from the gap into which the heat shield plate is inserted. Particularly, if the furnace interior is at a high temperature in the range of 2000°C, the amount of radiant heat significantly increases, and the packing is easily heated above its heat-resistant temperature.

Prior Art Documents

Patent Documents

[0005] [Patent Document 1] Japanese Patent Application Publication No. 4-351380 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] Against the backdrop of the above circumstances, the present invention aims to provide a continuous heat treatment furnace that can improve the problem of deterioration of sealing performance at the entrance and exit of the heating chamber where high temperatures are reached. [Means for solving the problem]

[0007] Thus, the continuous heat treatment furnace in the first aspect of this invention is defined as follows: A continuous heat treatment furnace having multiple heating chambers, Each of the aforementioned heating chambers is: The entrance into which the materials to be processed are brought, The discharge port from which the processed material is discharged, The entrance side has a double door, The exit side double door provided on the exit side, Equipped with, The aforementioned double door on the entrance side is The aforementioned entrance is sealed with an insulated door on the entrance side, An entrance-side sealing door is provided on the outside of the compartment where the aforementioned entrance-side insulated door is installed, and closes the opening on the upstream side in the transport direction of the compartment. It consists of, The aforementioned double door on the exit side is, An exit-side insulated door that blocks the aforementioned exit, An exit-side sealing door is provided on the outside of the compartment where the aforementioned exit-side insulated door is installed, and closes the opening on the downstream side in the transport direction of the compartment, It consists of.

[0008] In this first phase of the continuous heat treatment furnace, the doors on the inlet and outlet sides of the heating chamber, where deterioration of sealing performance is a problem, are double doors consisting of an insulated door and a sealing door. When the insulated door is blocking the inlet or outlet, even when the sealing door is opened or closed, the sealing door does not directly face the inlet or outlet, thus avoiding or reducing damage to the sealing material due to radiant heat from the inlet or outlet.

[0009] In this case, it is preferable that the inlet-side insulated door and the inlet-side sealing door that constitute the inlet-side double door, and / or the outlet-side insulated door and the outlet-side sealing door that constitute the outlet-side double door, are configured to open and close independently of each other (second aspect).

[0010] Furthermore, if the system includes a first heating chamber and a second heating chamber adjacent to the first heating chamber, The outlet seal door of the first heating chamber and the front filling seal door of the second heating chamber can be configured to open and close simultaneously (third aspect).

[0011] The fourth aspect of this invention is defined as follows: In the first phase, the apparatus includes an inlet heat shield plate positioned between the inlet seal door in an open state and the workpiece passing near the inlet seal door, and / or an outlet heat shield plate positioned between the outlet seal door in an open state and the workpiece passing near the outlet seal door, and / or an outlet heat shield plate positioned between the outlet seal door in an open state and the workpiece passing near the outlet seal door, and for which the outlet seal door is shielded from heat. According to this defined fourth aspect, the sealing member of the sealing door can be protected from radiant heat emitted by a high-temperature workpiece passing near the sealing door.

[0012] The fifth aspect of this invention is defined as follows: In the first phase, the heating chamber is An insulating wall that partitions the storage chamber in which the object to be processed is contained, A gas supply port is provided on the outside of the aforementioned insulating wall for supplying atmospheric gas, A gas exhaust port provided inside the heat insulation wall for exhausting the atmosphere gas to the outside of the room, is provided. According to the fifth aspect defined as above, it is possible to suppress the leakage of the low melting point substance gasified in the accommodation chamber to the outside of the heat insulation wall due to the gas flow from the outside to the inside of the heat insulation wall.

[0013] The sixth aspect of this invention is defined as follows. That is, In the first aspect, a transport container that houses the object to be processed inside and has a communication port formed in the bottom wall portion, arm-type transport means for transporting the transport container to a predetermined position in the heating chamber, a gas exhaust port provided so as to be able to engage or be close to and face the communication port of the transport container placed at a predetermined position in the heating chamber, is provided. According to the sixth aspect defined as above, it is possible to exhaust the low melting point substance gasified by heating to the outside of the room through the gas exhaust port while sealing the low melting point substance gasified by heating in the transport container as much as possible.

Brief Description of Drawings

[0014] [Figure 1] It is a figure which shows the whole structure of the continuous heat treatment furnace which concerns on 1st Embodiment of this invention. [Figure 2] It is a figure which shows the door which opens and closes the carry-out port of the prechamber of FIG. 1 and the door which opens and closes the carry-in port of the first heating chamber with its peripheral part. [Figure 3] It is explanatory drawing about an example of the opening and closing operation | movement of the door shown in FIG. 2. [Figure 4] It is a figure which shows the door for opening and closing provided before and behind the second heating chamber of FIG. 1 with its peripheral part. [Figure 5] It is explanatory drawing about an example of the opening and closing operation | movement of the door which opens and closes the carry-out port of the first heating chamber and the door which opens and closes the carry-in port of the second heating chamber. [Figure 6] It is a figure which shows the modification which made the movement mechanism of the heat shielding board different. [Figure 7] It is operation explanatory drawing about the modification of FIG. 6. [Figure 8] This figure shows the configuration of the latter half of a continuous heat treatment furnace according to a second embodiment of the present invention. [Figure 9] This figure shows the support base of the third heating chamber and its surrounding area in the same embodiment. [Modes for carrying out the invention]

[0015] Next, embodiments of the present invention will be described in detail below.

[0016] Figure 1 shows a schematic overall configuration of a continuous heat treatment furnace according to the first embodiment of the present invention. In the figure, reference numeral 1 denotes a roller hearth type continuous heat treatment furnace that continuously heat-treats a workpiece W such as steel or ceramics (hereinafter sometimes simply referred to as heat treatment furnace 1).

[0017] In this heat treatment furnace 1, the material to be treated W is transported inside a box-shaped transport container 4. The transport container 4 has a bottom wall, side walls, and a top wall, and as a whole it has a rectangular parallelepiped shape. A part of the wall (for example, the top wall) is separable from the other walls, and the material to be treated W can be placed inside through the opening created when the wall is separated. The transport container 4, with the material to be treated W inside, is placed on a tray 3 and moves through the furnace on transport rollers 40. The materials of the transport container 4 and the tray 3 can be selected according to the heating temperature, etc., and examples include heat-resistant alloys, carbon materials such as graphite, and C / C composites.

[0018] The heat treatment furnace 1 comprises a cylindrical furnace body 5 that extends horizontally in the figure. An inlet 6 for loading is formed on the left side of the furnace body 5, and an outlet 7 for removal is formed on the right side of the furnace body 5. These inlet 6 and outlet 7 are equipped with doors 8 and 9 (both airtight sealing doors) which are opened and closed by an air cylinder type opening and closing device 18, respectively. In other words, in this example, the transport container 4 loaded from the left side of the figure is transported to the right side of the figure while the material to be treated W is heat-treated.

[0019] Inside the furnace body 5, four processing chambers are provided along the conveying direction: a front chamber 10, a first heating chamber 11, a second heating chamber 12, and a cooling chamber 16. Each processing chamber is equipped with a pressure-resistant furnace shell and is connected to a vacuum exhaust system (not shown), making it possible to create a vacuum (reduced pressure) state. Each processing chamber is also connected to an atmospheric gas supply device (not shown) for supplying an atmospheric gas (e.g., nitrogen gas) into the chamber.

[0020] The anteroom 10 is a section that prevents air from entering the heating chambers 11 and 12. When the transport container 4 containing the material to be processed W is loaded through the inlet 6 and the door 8 is closed, the air in the anteroom 10 is exhausted to the outside through a vacuum exhaust device (not shown in the diagram). During repressurization, an atmospheric gas is supplied to the chamber to restore the pressure to, for example, atmospheric pressure.

[0021] The first heating chamber 11 is a section in which the workpiece W is heated based on a predetermined heat pattern. The first heating chamber 11 has a heat-resistant insulating material inside, which constitutes an insulating wall 31. This insulating wall 31 partitions a storage chamber 32 in which the workpiece W is housed, and an electric heater 35 is provided inside the area enclosed by the insulating wall 31 as a heating means.

[0022] On the outside of the insulating wall 31, multiple gas supply ports 47a are provided for supplying nitrogen gas, which is sent as an atmospheric gas through the gas supply pipe 47, into the room. In this example, gas supply ports 47a are provided in the compartment 22 surrounding the entrance 11a of the first heating chamber 11, in the area between the furnace shell of the first heating chamber 11 and the insulating wall 31, and in the compartment 23 surrounding the exit 11b of the first heating chamber 11. It is desirable to install a mass flow controller on the gas supply path, including the gas supply pipe 47, in order to make the gas supply amount variable. On the other hand, a gas exhaust port 48a, which serves as the tip of the exhaust pipe 48, is provided on the inside of the insulated wall 31. A vacuum evacuation device (not shown) is provided on the exhaust gas flow path including the exhaust pipe 48, and by operating the vacuum evacuation device, the gas drawn in from the gas exhaust port 48a is exhausted to the outside through the exhaust gas flow path including the exhaust pipe 48. In the first heating chamber 11 configured in this way, the gas supplied to the outside of the insulating wall 31 flows through the permeable insulating wall 31 and through the gap between the insulating wall 31 and the insulating doors 55A and 57A, towards the inside of the insulating wall 31. Examples of permeable insulating materials include ceramic fibers mainly composed of alumina and silica, and carbon fibers mainly composed of carbon.

[0023] Forming such a gas flow is effective in improving the problem of poor sealing at the inlet and outlet of the heating chamber. When a workpiece W containing a low-melting-point substance is heat-treated in the heating chamber, the low-melting-point substance vaporizes and scatters into the furnace during heating. When the vaporized low-melting-point substance comes into contact with the water-cooled portion for O-ring protection attached to the seal doors 55B and 57B (described later), it solidifies again and grows in the water-cooled portion. This can cause problems when trying to open or close the doors after the heat treatment is complete, or lead to sealing failures. Therefore, in this embodiment, a state is created in which the pressure inside the insulating wall 31 is always low during the heat treatment, and gas flows toward the inside of the insulating wall 31. This prevents the evaporated low-melting-point material from leaking out to the outside of the insulating wall 31, and avoids sealing failures caused by the re-solidification of the low-melting-point material.

[0024] The second heating chamber 12, following the first heating chamber 11, is a section in which the object to be processed W is heated based on a predetermined heat pattern, similar to the first heating chamber 11. The components of the second heating chamber 12 are basically the same as those of the first heating chamber 11, and common components are indicated using the same reference numerals, and their explanations are omitted.

[0025] The cooling chamber 16, which follows the second heating chamber 12, is a section for cooling the workpiece W. As shown in Figure 1, the cooling chamber 16 is equipped with a cooler 36 for atmospheric gas cooling and a fan (not shown) for circulating the atmospheric gas, and cools the high-temperature workpiece W that has been heated in the second heating chamber 12.

[0026] Each processing chamber constituting the heat treatment furnace 1 has conveying rollers 40 arranged in parallel along the conveying direction. While metal rollers made of stainless steel or heat-resistant cast steel can be used for the rollers 40, these are prone to deformation when used at temperatures above 1100°C. Therefore, in this example, rollers made of C / C composite, which have high heat resistance and do not experience significant strength reduction even at temperatures above 2000°C, are used.

[0027] Multiple rollers 40, arranged in the front chamber 10, the first heating chamber 11, the second heating chamber 12, and the cooling chamber 16, constitute roller groups 42, 43, 44, and 45, respectively. These roller groups 42, 43, 44, and 45 are driven independently and sequentially transport the transport container 4 on the tray 3 downstream in the transport direction (to the right in Figure 1).

[0028] As shown in Figure 1, multiple compartments 20-22, 23-25, and 26-28, which serve as door-enclosed chambers, are connected between the anteroom 10, the first heating chamber 11, the second heating chamber 12, and the cooling chamber 16. These compartments airtightly enclose the area between each processing chamber (for example, between the anteroom 10 and the first heating chamber 11), sealing the interior from the outside air. The walls separating adjacent compartments are provided with openings to allow the material to be processed W to pass through, and each compartment is equipped with a door that closes the opening for the material to be processed W to pass through (including the entrance and exit of each processing room) and an air cylinder type opening / closing device 19 for opening and closing the door.

[0029] The following describes the doors for opening and closing that are provided in each compartment. For example, as shown in Figure 2, the compartment 20 surrounding the exit 10b of the anteroom 10 is provided with a seal door 50 that closes the exit 10b of the anteroom 10. The seal door 50 is made of steel plate material, and an O-ring 51 (see enlarged section) is attached to the surface of the seal door 50 facing the periphery of the exit 10b as a sealing member so as to surround the exit 10b, allowing the seal door 50 to make airtight contact with the periphery of the exit 10b. The seal door 50 is connected to the support frame 53 via a pair of link pieces 52, one above and one below, and one on the left and right (in a direction perpendicular to the transport direction, and perpendicular to the plane of the paper in Figure 2). The support frame 53 is connected to the lower end of the lifting rod 19a that extends downward from the opening / closing device 19, and both of its left and right ends are supported by guide rails (not shown) so that it can slide vertically. When the lifting rod 19a is raised or lowered, the seal door 50 moves up and down together with the support frame 53.

[0030] In this configuration, when the support frame 53 is lowered and the seal door 50 faces the outlet 10b, the lower part of the seal door 50 is received by a receiving member (not shown), preventing the seal door 50 from descending any further. If the support frame 53 descends further in this state, the link piece 52 rotates, pressing the seal door 50 against the periphery of the outlet 10b, and the outlet 10b is airtightly closed by the seal door 50. On the other hand, when the support frame 53 is raised, the link piece 52 rotates in the opposite direction to when it was lowered, the pressing force disappears, and a gap is created between the seal door 50 and the periphery of the outlet 10b. The seal door 50 rises together with the support frame 53, and the outlet 10b is opened. The mechanism for opening and closing the sealed door 50 in compartment 20 has been described above, but the mechanisms for opening and closing the doors in the other compartments 21 to 28 are basically the same as those for the sealed door 50.

[0031] As shown in Figure 2, the entrance 11a side of the first heating chamber 11, which is adjacent to the anteroom 10, is provided with a double entrance door 55 consisting of an entrance-side insulated door 55A and an entrance-side sealing door 55B. The inlet-side insulated door 55A is a plate-shaped member made of heat-resistant insulating material that closes the entrance 11a formed at one end (upstream side in the transport direction) of the substantially cylindrical insulating wall 31 of the first heating chamber 11, shielding it from radiant heat from the containment chamber 32 surrounded by the insulating wall 31 and maintaining the containment chamber 32 at a high temperature. This inlet-side insulated door 55A is installed in a compartment 22 formed outside the entrance 11a (upstream side in the transport direction) so as to surround the entrance 11a, and is supported so as to be able to be raised and lowered by an opening and closing device 19.

[0032] The entrance-side sealing door 55B is equipped with an O-ring 51 as a sealing member and is a door for airtightly closing the first heating chamber 11. The entrance-side sealing door 55B is located in compartment 21 further outside (upstream in the transport direction) of compartment 22 where the entrance-side insulating door 55A is provided. The entrance-side sealing door 55B is supported so as to be able to move up and down by an opening / closing device 19 provided in compartment 21, so as to be able to close the opening 22a on the upstream side in the transport direction of compartment 22 where the entrance-side insulating door 55A is provided from the outside of compartment 22.

[0033] In this configuration of the double entrance door 55, if the entrance insulated door 55A is blocking the entrance 11a, even if the entrance sealing door 55B is opened and closed vertically, the entrance sealing door 55B will not directly face the entrance 11a, thus avoiding or mitigating damage to the O-ring 51 due to radiant heat from the entrance 11a.

[0034] Figure 3 shows an example of door opening and closing operations for the seal door 50 that opens and closes the outlet 10b of the anteroom 10 and the double entrance door 55 that opens and closes the entrance 11a of the first heating chamber 11. When transporting the material to be processed W, it is necessary to open the three doors provided between the front chamber 10 and the first heating chamber 11. In this embodiment, starting from the state in which all doors shown in Figure 2 are closed, as shown in Figure 3(A), the sealing doors 50 and 55B are raised first while the insulating door 55A that closes the entrance 11a is kept closed. After the sealing doors 50 and 55B have finished rising, the insulating door 55A is raised as shown in Figure 3(B). In this way, while the sealing doors 50 and 55B are opening, the radiant heat from the entrance 11a is shielded by the insulating door 55A, and damage to the O-ring 51 due to radiant heat from the entrance 11a can be avoided or reduced.

[0035] Furthermore, when closing each door, starting from the open state shown in Figure 3(B), the insulated door 55A is lowered first, as shown in Figure 3(A), and the entrance 11a is closed by the insulated door 55A. After blocking the entrance 11a to shield it from radiant heat, the seal doors 50 and 55B are lowered. In this way, damage to the O-ring 51 due to radiant heat from the entrance 11a during the closing operation can be avoided or mitigated.

[0036] Next, we will describe the door provided between the first heating chamber 11 and the second heating chamber 12. As shown in Figure 4, between the first heating chamber 11 and the second heating chamber 12, an exit double door 57 consisting of an exit insulated door 57A and an exit sealing door 57B is provided on the exit 11b side of the first heating chamber 11, and an entry double door 58 consisting of an entry insulated door 58A and an entry sealing door 58B is provided on the entrance 12a side of the second heating chamber 12. The opening and closing mechanisms of each door are basically the same as those of the double door 55 described above, but both the exit sealing door 57B and the entry sealing door 58B are connected to a common support frame 53 provided in the compartment 24. These two sealing doors 57B and 58B are configured to open and close simultaneously by operating an opening and closing device 19 provided in the compartment 24.

[0037] Figure 5 shows an example of the opening and closing operation of a door located between the first heating chamber 11 and the second heating chamber 12. When transporting the material to be processed W, it is necessary to open the four doors provided between the first heating chamber 11 and the second heating chamber 12. In this embodiment, starting from the state in which all doors shown in Figure 4 are closed, as shown in Figure 5(A), the sealing doors 57B and 58B are raised first while keeping the insulating door 57A that closes the outlet 11b of the first heating chamber 11 and the insulating door 58A that closes the entrance 12a of the second heating chamber 12 in a closed state. After the sealing doors 57B and 58B have finished rising, the insulating doors 57A and 58A are raised as shown in Figure 5(B). In this way, damage to the O-ring 51 due to radiant heat from the outlet 11b and entrance 12a during the door opening operation can be avoided or reduced.

[0038] In this embodiment, after the sealing doors 57B and 58B move above the compartment 24 and open the openings 23a and 25a, the heat shield plate 62 extends horizontally (in a direction perpendicular to the plane of the paper in Figure 5) from the side wall of the compartment 24 directly below the sealing doors 57B and 58B, as shown in Figure 5(B). The workpiece W, which exits the outlet 11b of the first heating chamber 11 and heads toward the second heating chamber 12, has been heated to a predetermined temperature in the first heating chamber 11. When the high-temperature workpiece W passes near the retracted seal doors 57B and 58B, there is a risk that the O-rings 51 attached to the seal doors 57B and 58B may be damaged by radiant heat from the workpiece W. Therefore, in this embodiment, a heat shield 62 is provided between the seal doors 57B and 58B and the workpiece W passing near the seal doors to prevent damage to the O-rings 51. Furthermore, in order to prevent heat from entering the O-ring 51, it is effective to extend the heat shield plate 62 in the left-right and front-back directions (conveying direction) so that the O-ring 51 attached to the seal doors 57B and 58B is sufficiently hidden when viewed from above.

[0039] Next, we will describe the door located between the second heating chamber 12 and the cooling chamber 16. As shown in Figure 4, between the second heating chamber 12 and the cooling chamber 16, a double exit door 59 consisting of an exit-side insulated door 59A and an exit-side sealing door 59B is provided on the exit side 12b of the second heating chamber 12, and an in-side sealing door 60 is provided on the entrance side 16a of the cooling chamber 16. Regarding the doors in this area, when opening them, starting from the closed state shown in Figure 4, the sealing doors 59B and 60 are raised first while keeping the insulated door 59A that blocks the exit 12b closed. After the sealing doors 59B and 60 have finished rising, the insulated door 59A is raised. This prevents or reduces damage to the O-ring 51 due to radiant heat from the exit 12b during the door opening operation.

[0040] Furthermore, since the workpiece W passing through this region is at a high temperature, after the seal doors 59B and 60 move upward, a heat shield (not shown) can be extended directly below the seal doors 59B and 60, similar to the case of the seal doors 57B and 58B described above.

[0041] Furthermore, when closing each door, starting with all doors open, the insulated door 59A is lowered first to block the exit 12b with the insulated door 59A, thereby shielding it from radiant heat. After that, the sealing doors 59B and 60 are lowered, which helps to avoid or reduce damage to the O-ring 51 caused by radiant heat from the exit 12b during the closing operation.

[0042] Next, a series of heat treatment operations in the heat treatment furnace 1 will be described. Once the transport container 4 containing the material to be processed W is prepared, the roller group 42 is first driven to load the transport container 4 into the front chamber 10 (see Figure 1). When the door 8 is closed, the pressure is reduced using a vacuum exhaust device (not shown), and the air inside the chamber is released to the outside. After the vacuuming of the front chamber 10 is completed, an atmospheric gas is supplied into the front chamber 10, and the air inside the front chamber 10 is replaced with the atmospheric gas.

[0043] Subsequently, the exit seal door 50 of the front chamber 10 and the inlet double door 55 of the first heating chamber 11 are opened, the roller groups 42 and 43 are driven, the transport container 4 is transferred into the first heating chamber 11, and the inlet double door 55 is closed. The workpiece W inside the first heating chamber 11 is then heat-treated based on a predetermined heat pattern. An example of the maximum processing temperature at this time is 2100°C. In the first heating chamber 11, the supply and exhaust of an atmospheric gas (nitrogen gas) are performed simultaneously to prevent leakage of low-melting-point substances vaporized during heating. The amount of atmospheric gas supplied at this time can be set so that the pressure inside the insulating wall 31 remains low at all times during the heating process. For example, the amount can be increased at the beginning of the process and decreased at the end of the process, depending on the amount of degassing generated from the material W being processed during heating.

[0044] After the heating process in the first heating chamber 11 is completed, the double exit door 57 of the first heating chamber 11 and the double inlet door 58 of the second heating chamber 12 are opened, the roller groups 43 and 44 are driven, the transport container 4 is transferred into the second heating chamber 12, and the double inlet door 58 is closed. In the second heating chamber 12, the workpiece W is continued to be heated according to a predetermined heat pattern. In the second heating chamber 12, during the heating process, the supply and exhaust of atmospheric gas are performed simultaneously, as in the case of the first heating chamber 11.

[0045] After the heat treatment in the second heating chamber 12 is completed, the double exit door 59 of the second heating chamber 12 and the inlet seal door 60 of the cooling chamber 16 are opened, the roller groups 44 and 45 are driven to transport the transport container 4 into the cooling chamber 16, and the inlet seal door 60 is closed. In the cooling chamber 16, the workpiece W is cooled by circulating the atmospheric gas while being cooled by the cooler 36. After cooling, the door 9 is opened and the transport container 4 is transported out of the furnace, completing the series of operations related to the heat treatment of the workpiece W.

[0046] As described above, according to the continuous heat treatment furnace 1 of this embodiment, for example, the door on the entrance 11a side of the first heating chamber 11 is an entrance double door 55 consisting of an entrance insulated door 55A and an entrance sealing door 55B. If the entrance insulated door 55A is blocking the entrance 11a, even if the entrance sealing door 55B is opened or closed, the entrance sealing door 55B will not directly face the entrance 11a, thus avoiding or reducing damage to the O-ring 51 due to radiant heat from the entrance 11a.

[0047] For example, the insulated entrance door 55A and the sealing entrance door 55B that make up the double entrance door 55 are configured to open and close independently of each other, enabling actions that avoid or reduce damage to the O-ring 51 during both the opening and closing of the doors.

[0048] Furthermore, in the continuous heat treatment furnace 1 of this embodiment, the exit seal door 57B of the adjacent first heating chamber 11 and the inlet seal door 58B of the second heating chamber 12 are attached to a common support frame 53 and opening / closing device 19, allowing the two seal doors to be opened and closed simultaneously.

[0049] Furthermore, in the continuous heat treatment furnace 1 of this embodiment, as shown in Figure 5, a heat shield plate 62 is provided as an outlet heat shield plate that is located between the outlet seal door 57B with the opening 23a open and the workpiece W passing near the outlet seal door 57B, thereby protecting the O-ring 51 of the outlet seal door 57B from radiant heat emitted by the high-temperature workpiece W passing nearby. Furthermore, the heat shield 62 is located between the entry-side sealing door 58B and the workpiece W passing near the entry-side sealing door 58B, and also functions as an entry-side heat shield that shields the entry-side sealing door 58B from heat.

[0050] Furthermore, in the continuous heat treatment furnace 1 of this embodiment, the first heating chamber 11 is equipped with an insulating wall 31 that partitions the containment chamber 32 in which the material to be treated W is contained, a gas supply port 47a provided on the outside of the insulating wall 31, and a gas exhaust port 48a provided on the inside of the insulating wall 31. The gas flow from the outside to the inside of the insulating wall 31 can suppress the leakage of low-melting-point material that has been gasified in the containment chamber 32 to the outside of the insulating wall 31.

[0051] Figure 6 shows a modified example in which the mechanism for moving the heat shield 62 is different. In the above embodiment, the heat shield 62 is moved horizontally, but it is also possible to employ a mechanism for moving the heat shield 62 vertically. In this example of Figure 6, a second support frame 54 that supports the driven roller 46 and the heat shield 62 is connected to a support frame 53 that supports the seal doors 57B and 58B, and when the opening and closing device 19 is operated, the driven roller 46 and the heat shield 62 move up and down together with the seal doors 57B and 58B. Figure 6 shows the state in which the openings 23a and 25a provided on the transport path of the workpiece W are closed by the sealing doors 57B and 58B, and the driven roller 46 and the heat shield plate 62 are located below the transport surface 40a of the transport roller 40 on which the workpiece W is supported and transported.

[0052] In the example shown in Figure 6, when the object to be processed W is transported, the opening and closing device 19 is activated to raise the seal doors 57B and 58B. As shown in Figure 7, the driven roller 46 rises to the transport surface 40a, and the heat shield plate 62 is positioned between the seal doors 57B and 58B and the object to be processed W passing over the transport surface 40a. This protects the seal doors 57B and 58B from the radiant heat emitted by the high-temperature object to be processed W.

[0053] Figure 8 shows the configuration of a continuous heat treatment furnace 1B according to the second embodiment of the present invention (the configuration of the latter half of the heat treatment furnace, which differs from that of the first embodiment). The continuous heat treatment furnace 1B, following the pre-chamber 10, first heating chamber 11, and second heating chamber 12 of the continuous heat treatment furnace 1 of the first embodiment described above, is provided with a first transport chamber 65, a third heating chamber 66, a second transport chamber 67, and a cooling chamber 16B, as shown in Figure 8. Each processing chamber from the first transport chamber 65 to the cooling chamber 16B is equipped with a pressure-resistant furnace shell and is connected to a vacuum exhaust system (not shown), making it possible to create a vacuum (reduced pressure) in each chamber. In addition, each chamber is connected to an atmospheric gas supply source (not shown) for introducing atmospheric gas used for repressurization, etc.

[0054] The first conveying chamber 65 is located downstream of the second heating chamber 12 in the conveying direction and is equipped with a conveying device 71A as a first arm-type conveying means for conveying the workpiece W from the second heating chamber 12 to the third heating chamber 66. The conveying device 71A has two sets of extendable telescopic arms 72, 72 that are spaced apart in a direction perpendicular to the conveying direction of the workpiece W. The telescopic arm 72 is composed of a base arm 73, an intermediate arm 74 supported so as to be movable longitudinally relative to the base arm 73, and an upper arm 75 supported so as to be movable longitudinally relative to the intermediate arm 74. The intermediate arm 74 and the upper arm 75 work in conjunction to extend from the shortened state shown in Figure 8 toward the upstream side (left in the figure) or the downstream side (right in the figure) in the conveying direction, and are driven to be pulled back from the extended state toward the shortened state shown in Figure 8.

[0055] A third heating chamber 66 is provided downstream of the first conveying chamber 65 in the conveying direction. The third heating chamber 66 is a section for heating the workpiece W following the first heating chamber 11 and the second heating chamber 12. As shown in Figure 8, the third heating chamber 66 has a heat-resistant insulating material inside, which constitutes an insulating wall 77. Inside the insulating wall 77 is a containment chamber 78 for housing and heat-treating the workpiece W, and is provided with a support base 79 as a hearth and a heater 35 as a heating means.

[0056] On the outside of the insulating wall 77, a gas supply port 47a is provided for supplying nitrogen gas, which is sent as an atmospheric gas through the gas supply pipe 47, to the room, similar to the first heating chamber 11 and the second heating chamber 12. On the inside of the insulating wall 77, a gas exhaust port 48a for exhausting the atmospheric gas to the outside is provided for the exhaust pipe 48. As shown in Figure 9(A), the gas exhaust port 48a is installed to open upward at the same height as the upward support surface of the support base 79.

[0057] In this embodiment, the transport container 4 is provided with a communication port 85 in its bottom wall 84 that connects the inside and outside, as shown in Figure 9(B). The gas exhaust port 48a is installed in a position that overlaps with the communication port 85 of the transport container 4, which is placed in a predetermined position within the heating chamber, when observed projected in the vertical direction (see blowout diagram).

[0058] Furthermore, the third heating chamber 66 is provided with an inlet 66a side, which has an inlet double door 81 consisting of an inlet insulated door 81A and an inlet sealing door 81B, and the third heating chamber 66 is provided with an outlet 66b side, which has an outlet double door 82 consisting of an outlet insulated door 82A and an outlet sealing door 82B. Each door is located within a compartment 90-93. The structure of these double doors is the same as that described in the first embodiment, and a detailed explanation is omitted here.

[0059] A second transport chamber 67 is provided downstream of the third heating chamber 66 in the transport direction. The second transport chamber 67 is equipped with a transport device 71B, which serves as a second arm-type transport means for transporting the workpiece W from the third heating chamber 66 to the cooling chamber 16B. The transport device 71B is equipped with an extendable telescopic arm 72. This transport device 71B has the same configuration as the transport device 71A provided in the first transport chamber 65, and a detailed explanation is omitted here.

[0060] A cooling chamber 16B is provided downstream of the second conveying chamber 67 in the conveying direction. The cooling chamber 16B is equipped with a cooler 36 for cooling the atmospheric gas and a fan (not shown) for circulating the atmospheric gas. When the high-temperature workpiece W, which has been heat-treated in the third heating chamber 66, is brought into the cooling chamber 16B, the workpiece W is cooled. Two sets of lifting devices 88, 88 are provided in the cooling chamber 16B at intervals in the conveying direction as means of lifting and lowering. The tip of the lifting rod of the lifting device 88 moves up and down between the conveying rollers 40, 40, creating a gap for inserting the telescopic arm 72 necessary for transferring the workpiece W. In this embodiment, a similar lifting device 88 is also provided in the second heating chamber 12, which is located upstream of the first conveying chamber 65 in the conveying direction.

[0061] Next, the heat treatment operation in the continuous heat treatment furnace 1B will be described. Note that the opening and closing operations of each door when transporting the workpiece W are the same as in the first embodiment described above, so a detailed explanation will be omitted here. After the heat treatment in the second heating chamber 12 is completed, the transport container 4 (the transport container 4 containing the material to be treated W) is removed from the second heating chamber 12 by the transport device 71A and transported via the first transport chamber 65 to the third heating chamber 66, which is downstream in the transport direction (to the right in the diagram). The transport device 71A carries the transport container 4 to a predetermined position inside the third heating chamber 66 (specifically inside the storage chamber 78) and then places it on the support base 79. After the door 81 on the entrance side of the third heating chamber 66 is closed, the heat treatment in the third heating chamber 66 begins. In the third heating chamber 66, in order to prevent leakage of low-melting-point substances vaporized during heating, the supply and exhaust of atmospheric gas (nitrogen gas) are performed simultaneously. Here, in the third heating chamber 66, when the transport container 4 that has been transferred is placed on the support base 79, as shown in Figure 9(B), the gas exhaust port 48a for sucking and exhausting atmospheric gas is located directly below the communication port 85 of the transport container 4. Therefore, even if the low-melting-point substances contained in the material to be processed W are vaporized during heating, the vaporized low-melting-point substances are sealed inside the container 4 and exhausted to the outside through the gas exhaust port 48a, thus effectively suppressing leakage of the vaporized low-melting-point substances to the outside of the insulating wall 77. In this embodiment, the tray 3 is lattice-shaped, so the gas sucked out from the communication port 85 flows through the gaps between the grids of the tray 3 and is drawn into the gas exhaust port 48a.

[0062] After the heating process in the third heating chamber 66 is completed, the door 82 on the exit side of the third heating chamber 66 is opened, and the heated transport container 4 is removed by the transport device 71B and transported via the second transport chamber 67 to the cooling chamber 16B on the downstream side (right side in the diagram) in the transport direction. The transport container 4 that has been transported to the cooling chamber 16B is handed over to the lifting device 88 which is in the raised position, and then the lifting rod of the lifting device 88 is lowered, so that the transport container 4 is placed on the transport rollers 40.

[0063] Subsequently, the cooling chamber 16B closes its entrance door 60, and the atmospheric gas supplied to the chamber is circulated while being cooled by the cooler 36 to cool the workpiece W. After cooling, the door 9 is opened and the transport container 4 is removed from the furnace, completing the series of operations related to the heat treatment of the workpiece W.

[0064] As described above, the continuous heat treatment furnace 1B of this embodiment includes a transport container 4 with a communication port 85 formed in its bottom wall portion 84, a transport device 71A as an arm-type transport means for transporting the transport container 4 to a predetermined position in the third heating chamber 66, and a gas exhaust port 48a that can be positioned in close proximity to the communication port 85 of the transport container 4 placed in a predetermined position in the third heating chamber 66. This allows for the exhaust of low-melting-point substances that have been gasified by heating into the transport container 4 while keeping them sealed as much as possible inside the transport container 4, and exhausting them to the outside through the gas exhaust port 48a.

[0065] Although embodiments of the present invention have been described in detail above, these are merely examples. For example, in the above embodiments, the transport container and tray were constructed separately, but it is also possible to construct them as a single unit. Furthermore, the shape of the transport container is not limited to a rectangular parallelepiped and can be appropriately changed to match the shape of the heating chamber. In some cases, it is also possible to transport the materials to be processed directly without using a transport container. Furthermore, as in the second embodiment described above, when suctioning and exhausting gas from inside the container through the communication port of the transport container, it is also possible to configure the gas exhaust port to directly engage with the communication port. Furthermore, the sealing door that closes the exit of the anteroom and the sealing door on the entrance side of the first heating chamber are attached to a common support frame and opening / closing device, and it is also possible to configure the system so that the two sealing doors can be opened and closed simultaneously. Furthermore, the exit seal door of the second heating chamber and the entrance seal door that closes the entrance to the cooling chamber are attached to a common support frame and opening / closing device, making it possible to configure the system so that both seal doors can be opened and closed simultaneously. Furthermore, the gas supplied to the heating chamber and transport container is not limited to nitrogen gas, and can be changed as needed. In short, the present invention can be configured in various modified forms without departing from its spirit. [Explanation of Symbols]

[0066] 1.1B Continuous heat treatment furnace 4. Transport containers 11 1st heating chamber 11a,12a,66a Loading entrance 11b,12b,66b Exit 12 Second heating chamber Rooms 20-28, 90-94 31.77 Insulated wall 47a Gas supply port 48a Gas exhaust port 51 O-ring (sealing component) 55, 58, 81 Double doors on the entrance side 55A, 58A, 81A Insulated entrance door 55B, 58B, 81B Inlet-side sealed door 57, 59, 82 Double doors on the exit side 57A, 59A, 82A Outer side insulated door 57B, 59B, 82B Outside seal door 62 Heat shield 66 Third heating chamber 71A, 71B Conveying device (arm-type conveying means) 84 Bottom wall section 85 connecting ports W - Workpiece

Claims

1. A continuous heat treatment furnace having multiple heating chambers, Each of the aforementioned heating chambers is: The entrance into which the materials to be processed are brought, The discharge port from which the processed material is discharged, The entrance side has a double door, The exit side double door provided on the exit side, Equipped with, The aforementioned double door on the entrance side is The aforementioned entrance is sealed with an insulated door on the entrance side, An entrance-side sealing door is provided on the outside of the compartment where the aforementioned entrance-side insulated door is installed, and closes the opening on the upstream side in the transport direction of the compartment. It consists of, The aforementioned double door on the exit side is, An exit-side insulated door that blocks the aforementioned exit, An exit-side sealing door is provided on the outside of the compartment where the aforementioned exit-side insulated door is installed, and closes the opening on the downstream side in the transport direction of the compartment, A continuous heat treatment furnace consisting of [the above components].

2. The continuous heat treatment furnace according to claim 1, wherein the inlet-side insulated door and the inlet-side sealing door constituting the inlet-side double door, and / or the outlet-side insulated door and the outlet-side sealing door constituting the outlet-side double door, are configured to open and close independently of each other.

3. It comprises a first heating chamber and a second heating chamber adjacent to the first heating chamber, The continuous heat treatment furnace according to claim 1, wherein the outlet seal door of the first heating chamber and the front entry seal door of the second heating chamber are configured to open and close simultaneously.

4. A continuous heat treatment furnace according to claim 1, comprising an inlet heat shield plate positioned between an inlet seal door in an open state and the work to be treated passing near the inlet seal door, and / or an outlet heat shield plate positioned between an outlet seal door in an open state and the work to be treated passing near the outlet seal door, and for shielding the outlet seal door from heat.

5. The aforementioned heating chamber is An insulating wall that partitions the storage chamber in which the object to be processed is contained, A gas supply port is provided on the outside of the aforementioned insulating wall for supplying atmospheric gas, A gas exhaust port is provided on the inside of the aforementioned insulated wall to exhaust the atmospheric gas to the outside, A continuous heat treatment furnace according to claim 1, comprising:

6. A transport container that houses the object to be processed and has a communication opening formed in its bottom wall, An arm-type conveying means for conveying the conveying container to a predetermined position in the heating chamber, A gas exhaust port is provided so as to be able to engage with or be positioned in close proximity to the communication port of the transport container placed at a predetermined position within the heating chamber, A continuous heat treatment furnace according to claim 1, comprising:

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