Adjustable pressure heating furnace and method of use thereof

Abstract

The application relates to the technical field of semiconductor manufacturing equipment, in particular to an adjustable pressure heating furnace and a use method thereof, which comprises an inner frame and an outer frame in a furnace body and heating wires surrounding the inner frame and the outer frame, a sliding groove is arranged around the side wall of the inner frame, a plurality of clamping seats are slidably connected to the sliding groove, a plurality of ceramic rings are sleeved on the heating wires, the plurality of ceramic rings and the plurality of clamping seats are respectively clamped, an operating through hole is arranged in the side wall of the outer frame, and the heating wires are led out from the operating through hole. The application can solve the problem that the traditional ceramic ring is damaged and needs to be disassembled as a whole when the traditional ceramic ring is fixedly installed, greatly reduces the maintenance time, and improves the production efficiency; when the thermocouple detects temperature abnormity, the ceramic ring is rotated to make the heating wire clamped on the limiting clamping groove at different positions, the distance between the heating wire and the kettle body is controlled, the heating uniformity is timely and accurately controlled, and the like.

Description

Technical Field

[0001] This invention relates to the field of semiconductor manufacturing equipment technology, and in particular to an adjustable pressure heating furnace and its method of use. Background Technology

[0002] Semiconductor materials require temperature treatment using a furnace during fabrication. Taking gallium nitride (GaN) as an example, the fabrication of GaN crystals involves two chemical reactions: a low-temperature reaction and a high-temperature reaction. Therefore, the reaction chamber of the furnace used to control these reactions is divided into a low-temperature zone and a high-temperature zone.

[0003] Currently, heating furnaces are mainly installed in two ways: vertical and horizontal. For vertical heating furnaces, the reactor needs to be hoisted into the furnace from top to bottom during production. The furnace cavity consists of an inner frame and an outer frame. The inner frame contacts the reactor, and the heating wire is positioned between the inner and outer frames without contacting them to prevent short circuits. Existing technology uses multiple sets of high-temperature resistant, insulating ceramic rings around the heating wire to ensure it is securely mounted between the inner and outer frames. However, in practical use, the fixing of the ceramic rings to the heating wire and the reactor body is complex and requires high installation precision. If a single ceramic ring is damaged and needs replacement, the furnace body has multiple heating zones longitudinally. Replacing components in the lower zones requires prolonged shutdown and disassembly, resulting in long maintenance times and reduced production efficiency. Similarly, if a section of the heating wire is damaged, it involves the hassle of complete replacement or repair, increasing the risk of equipment failure and maintenance costs. Furthermore, during the use of the heating wire, if there is a positional shift or stress concentration caused by thermal expansion, resulting in uneven heating, it is difficult to adjust the problematic area. This leads to uneven heat distribution and affects the quality of the crystal material. Summary of the Invention

[0004] To solve the above-mentioned technical problems, the present invention provides an adjustable pressure heating furnace and its method of use.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] An adjustable pressure heating furnace includes a furnace body for heating a vessel. The furnace body includes an inner frame and an outer frame. A heating wire is arranged around the inner frame and the outer frame. A sliding groove is arranged around the side wall of the inner frame. Multiple retaining seats are slidably connected to the sliding groove. Several ceramic rings are sleeved on the heating wire, and the ceramic rings and the multiple retaining seats are respectively engaged. An operation through hole is opened on the side wall of the outer frame, and the heating wire is led out through the operation through hole and connected to an external power source.

[0007] The existing furnace body includes four heating zones: an upper zone, an upper-middle zone, a lower-middle zone, and a lower zone. The upper zone has one heating zone, the upper-middle zone has two, the lower-middle zone has two, and the lower zone has one. This design ensures more precise temperature control for each section of the vessel. Open spaces are created between any two heating zones to allow for temperature leakage and maintain a certain temperature difference between them. The temperature difference between any two adjacent heating zones is approximately 30°C. Insulation cotton is attached to the inner wall of the outer frame between the heating wire and the outer frame, ensuring more comprehensive heat distribution to the vessel within the inner frame. The heating wire is made of stainless steel, which, compared to the existing copper material, avoids oxidation and rust, reducing maintenance and replacement costs.

[0008] Furthermore, the ceramic ring is a hinged ceramic ring with an opening on its sidewall. The width of the opening is the same as the diameter of the heating wire. A fixing groove is also provided on the inner sidewall of the ceramic ring, and the fixing groove is positioned opposite the opening. The opening width of the hinged ceramic ring matches the diameter of the heating wire, allowing the ceramic ring to be directly inserted into or removed from the heating wire laterally. Compared to traditional closed ceramic rings that require insertion or removal from the end of the heating wire, the open structure not only facilitates the rotation of the mounting bracket but also facilitates the replacement of the ceramic ring, solving the problem of requiring complete disassembly when replacing lower or middle ceramic rings in traditional structures.

[0009] Furthermore, the fixing groove is arranged in a stepped structure along the inner wall of the ceramic ring, and a limiting slot is evenly spaced on the fixing groove. The groove surface of the limiting slot has the same diameter as the heating wire. The stepped structure of the fixing groove ensures that the straight-line distance between the limiting slot and the outer wall of the ceramic ring is different at any position. Based on this, by holding the heating wire in the limiting slot at different positions, the distance between that section of the heating wire and the surface of the vessel can be finely adjusted, thereby changing the local heat transfer efficiency and precisely solving the problem of uneven heating caused by thermal expansion, ceramic ring misalignment, or local aging. In actual operation, if the heat transfer efficiency of that section of the heating wire is low, the heating wire is placed in the fixing groove corresponding to the lower thickness, so that the heating wire is closer to the vessel. If the heat transfer efficiency of that section of the heating wire is high, the heating wire is placed in the fixing groove corresponding to the higher thickness, so that the heating wire is further away from the vessel, ultimately achieving the goal of uniform overall heat transfer efficiency.

[0010] Furthermore, multiple card holders are arranged at equal intervals and are fixedly connected by connecting rings. All card holders are fixedly connected into a single unit by the connecting rings. When the connecting rings are driven to rotate, all card holders are simultaneously driven to rotate along the sliding grooves. This structural design facilitates the movement of the ceramic ring from any position to the operating through-hole for inspection or replacement, significantly improving maintenance efficiency for a longitudinally arranged furnace structure.

[0011] Furthermore, a rotating lever is provided on the connecting ring, and the vertical height of the rotating lever corresponds to that of the operating through hole. The operator controls the rotating lever through the operating through hole, thereby driving the entire structure of the card holder. Its position is aligned with the operating through hole, allowing the operator to easily operate through the operating through hole. Without opening the furnace body or performing large-scale disassembly, the entire assembly can be precisely rotated to move the target area to the operating window, completing the work of inspecting and replacing damaged parts.

[0012] Furthermore, limiting baffles are provided on both sides of the card holder, and the distance between the outer diameter of the ceramic ring and the limiting baffles on both sides is equal. The limiting baffles are used to laterally limit the insertion of the ceramic ring, ensuring that the ceramic ring is firmly locked in the card holder, so that the ceramic ring can only rotate within its groove, ensuring structural stability and adjustment accuracy.

[0013] Furthermore, a mounting base is provided on the operating through-hole, and the mounting base is provided with an operating window and a mounting window. The heating wire passes through the mounting window and is led to the outside. The operating window is provided with an openable and closable cover. The mounting base provides functional zoning and sealing management for the operating through-hole. The mounting window is dedicated to fixing and leading out the heating wire lead, ensuring the stability and sealing of the electrical connection. The operating window is the working channel for maintenance and adjustment. The openable and closable cover closes the furnace cavity during non-operation periods, ensuring a stable temperature field and good heat preservation effect inside the furnace and preventing foreign objects from entering. It can be opened for operation during operation.

[0014] Furthermore, the outer frame is also equipped with thermocouples for temperature measurement, which are connected to the outside via flexible wires. The thermocouples are arranged around the inner sidewalls of the outer frame to sense the temperature at various locations within the furnace in real time, providing real-time data for determining whether the temperature is abnormal.

[0015] A method of using an adjustable pressure heating furnace includes the following steps:

[0016] S1: Assembly preparation: Place several ceramic rings on the heating wire, and each ceramic ring is connected to a corresponding bracket. The fixing groove side of the ceramic ring faces the inner frame, so that the heating wire is held in the middle of the fixing groove. The end of the heating wire is led out through the operation through hole and connected to the power supply.

[0017] S2: Replace the ceramic ring, open the cover of the operating through hole, drive the connecting ring by rotating the lever, and then drive all the card holders to rotate along the slide. When any ceramic ring passes the end of the heating wire, it will pass through the opening of the ceramic ring until the ceramic ring to be replaced moves to the position of the operating through hole. Then rotate the ceramic ring so that the opening side of the ceramic ring faces the inner frame, pull the ceramic ring out laterally through the side wall opening, and replace it with a new ceramic ring.

[0018] S3: Replace the heating wire. Disconnect the wire connecting the end of the heating wire to the power supply. Take a new heating wire and fix it to one end of the old heating wire. That is, connect one end of the new heating wire to one end of the old heating wire by binding or external clamping. Then pull the end of the old heating wire outward until the new heating wire is completely inserted between the inner and outer frames. Then separate the new heating wire from the old heating wire and connect the new heating wire to the power supply wire to complete the replacement.

[0019] S4: Uneven heating. When the thermocouple detects an abnormal temperature, the connecting ring is driven by rotating the lever to rotate the ceramic ring in the abnormal area to the operating through hole. By rotating and adjusting the ceramic ring, the heating wire at that location is locked in different limiting slots according to the abnormal temperature value. Based on the different thicknesses of the fixing slots at different positions, the distance between the heating wire and the vessel body is controlled.

[0020] Furthermore, in step S1 above, the distance between any two of the limiting slots keeps the heating wire suspended, preventing it from touching the inner or outer frame.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1. By setting up a movable ceramic ring and a sliding groove type card holder structure, this invention can solve the problem that the entire machine needs to be stopped and disassembled when a single ceramic ring is damaged due to fixed installation. The movable ceramic ring design makes it easy to rotate and adjust the heating wire. At the same time, the ceramic ring can be directly inserted or removed from the side, achieving the effect of quickly repairing or replacing damaged ceramic rings, greatly reducing maintenance time and improving production efficiency.

[0023] 2. By setting up an operation through hole, the present invention facilitates the inspection and replacement of heating wires at any position on the furnace body, thereby solving the problem of having to replace the entire furnace or scrap the furnace body when the heating wire is partially damaged, and significantly reducing maintenance costs and the risk of equipment scrapping.

[0024] 3. When the thermocouple detects an abnormal temperature, the present invention rotates and adjusts the ceramic ring to make the heating wire lock onto the limiting slots at different positions, thereby controlling the distance between the heating wire and the vessel body. This solves the problem of uneven heating caused by thermal expansion or ceramic ring misalignment, achieves timely and precise control of heating uniformity, and ensures the quality of crystal materials. Attached Figure Description

[0025] Figure 1 This is a three-dimensional structural schematic diagram of the present invention;

[0026] Figure 2 This is a partial structural schematic diagram of the present invention;

[0027] Figure 3 This is a schematic diagram of the disassembled structure of the furnace body;

[0028] Figure 4 This is a schematic diagram of the ceramic ring structure;

[0029] Figure 5 This is a schematic diagram of the ceramic ring structure in Example 4;

[0030] Figure 6 This is a schematic diagram of the ceramic ring structure in Example 5;

[0031] Attached diagram labels: 1-furnace body, 2-inner frame, 3-outer frame, 4-heating wire, 5-slide groove, 6-card seat, 7-ceramic ring, 8-operation through hole, 9-opening, 10-fixing groove, 11-limiting slot, 12-connecting ring, 13-rotation lever, 14-limiting baffle, 15-mounting seat, 1501-operation window, 1502-mounting window, 16-cover plate, 17-disc spring washer, 18-anti-detachment card. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0033] Example 1, as Figures 1-4 As shown, the present invention discloses an adjustable pressure heating furnace, including a furnace body 1 for heating a vessel. The furnace body 1 includes an inner frame 2 and an outer frame 3. A heating wire 4 is arranged around the inner frame 2 and the outer frame 3. A sliding groove 5 is arranged around the side wall of the inner frame 2. A plurality of retaining seats 6 are slidably connected to the sliding groove 5. A plurality of ceramic rings 7 are sleeved on the heating wire 4. The plurality of ceramic rings 7 and the plurality of retaining seats 6 are respectively engaged. An operation through hole 8 is opened on the side wall of the outer frame 3. The heating wire 4 is led out through the operation through hole 8 and connected to an external power source.

[0034] Specifically, the existing furnace body 1 includes four heating zones: an upper zone, an upper-middle zone, a lower-middle zone, and a lower zone. The upper zone has one heating zone, the upper-middle zone has two, the lower-middle zone has two, and the lower zone has one. This design ensures more precise temperature control for each section of the vessel. A perforated design separates any two heating zones to allow for temperature leakage and maintain a certain temperature difference between them. The temperature difference between any two adjacent heating zones is approximately 30°C. Insulation cotton is attached to the inner wall of the outer frame 3 between the heating wire 4 and the outer frame 3, ensuring that heat is more comprehensively directed to the vessel within the inner frame 2. The heating wire 4 is made of stainless steel, which, compared to the existing copper material, avoids oxidation and rust, reducing maintenance and replacement costs.

[0035] The ceramic ring 7 is a movable ceramic ring with an opening 9 on its side wall. The width of the opening 9 is the same as the diameter of the heating wire 4. The inner side wall of the ceramic ring 7 is also provided with a fixing groove 10, which is arranged opposite to the opening 9. Specifically, the width of the opening 9 of the movable ceramic ring matches the diameter of the heating wire 4, allowing the ceramic ring 7 to be directly inserted into or removed from the heating wire 4 from the side. Compared with the traditional closed ceramic ring 7, which must be inserted or removed from the end of the heating wire 4, the structure of the opening 9 not only facilitates the rotation of the mounting base 6 (when the heating wire 4 passes through the operating through hole 8, its axis is perpendicular to the side wall of the inner frame 2, thus ensuring that the mounting base 6 can rotate normally), but also facilitates the replacement of the ceramic ring 7, solving the problem that the traditional structure requires the entire structure to be disassembled when replacing the lower or middle ceramic ring 7.

[0036] The fixing groove 10 is arranged in a stepped structure along the inner wall of the ceramic ring 7. Limiting slots 11 are evenly spaced on the fixing groove 10, and the groove surface of the limiting slots 11 has the same diameter as the heating wire 4. Specifically, the stepped structure of the fixing groove 10 ensures that the straight-line distance between the limiting slots 11 at any position and the outer wall of the ceramic ring 7 is different (i.e., different radial positions of the heating wire 4, and different distances from the inner frame 2 or the vessel body). Based on this, by holding the heating wire 4 in the limiting slots 11 at different positions, the distance between that section of the heating wire 4 and the surface of the vessel body can be finely adjusted, thereby changing the local heat transfer efficiency and precisely solving the problem of uneven heating caused by thermal expansion, ceramic ring 7 misalignment, or local aging. In actual operation, if the heat transfer efficiency of that section of the heating wire 4 is low, the heating wire 4 is placed in the fixing groove 10 with the lower thickness, making the heating wire 4 closer to the vessel body. If the heat transfer efficiency of the heating wire 4 is too high, the heating wire 4 is placed on the fixed groove 10 with a corresponding high thickness, so that the heating wire 4 is further away from the vessel body, and finally the purpose of uniform heat transfer efficiency is achieved.

[0037] Multiple card holders 6 are arranged at equal intervals and are fixedly connected by connecting rings 12. Specifically, all card holders 6 are fixedly connected into a whole by connecting rings 12. When the connecting rings 12 are driven to rotate, all card holders 6 (and the ceramic rings 7 and heating wires 4 they support) are simultaneously driven to rotate along the slide grooves 5. This structure allows the ceramic rings 7 to be moved from any position to the operating through-holes 8 for inspection or replacement, significantly improving maintenance efficiency for the longitudinally arranged furnace body 1.

[0038] A rotating lever 13 is provided on the connecting ring 12, and the rotating lever 13 corresponds to the vertical height of the operating through hole 8. Specifically, the operator controls the rotating lever 13 through the operating through hole 8, thereby driving the entire structure of the card holder 6. Its position is aligned with the operating through hole 8, allowing the operator to easily operate through the operating through hole 8. Without opening the furnace body 1 or performing large-scale disassembly, the entire assembly can be precisely rotated to move the target area to the operating window 1501, completing the work of inspecting and replacing damaged parts.

[0039] Limiting baffles 14 are provided on both sides of the card holder 6, and the distance between the outer diameter of the ceramic ring 7 and the limiting baffles 14 on both sides is equal. Specifically, the limiting baffles 14 are used to laterally limit the insertion of the ceramic ring 7, ensuring that the ceramic ring 7 is firmly locked in the card holder 6, so that the ceramic ring 7 can only rotate within its groove (for adjusting the position of the heating wire 4 on the fixed groove 10, or for removal and replacement), ensuring structural stability and adjustment accuracy.

[0040] A mounting base 15 is provided on the operating through-hole 8. The mounting base 15 has an operating window 1501 and a mounting window 1502. The heating wire 4 passes through the mounting window 1502 and is led to the outside. An openable cover plate 16 is provided on the operating window 1501. Specifically, the mounting base 15 provides functional zoning and sealing management for the operating through-hole 8. The mounting window 1502 is dedicated to fixing and leading out the heating wire 4 lead, ensuring the stability and sealing of the electrical connection. The operating window 1501 is the working channel for maintenance (replacing the ceramic ring 7 and heating wire 4) and adjustment (rotating the ceramic ring 7 to change the slot). The openable cover plate 16 closes the furnace cavity during non-operation periods, ensuring a stable temperature field, good heat preservation, and preventing foreign objects from entering. It can be opened for operation during operation.

[0041] The outer frame 3 is also equipped with thermocouples for temperature measurement, which are connected to the outside via flexible wires. Specifically, the thermocouples are arranged around the inner sidewalls of the outer frame 3 to sense the temperature at various locations inside the furnace body 1 in real time, providing real-time data for determining whether the temperature is abnormal.

[0042] Example 2, based on Example 1, proposes a method for using an adjustable pressure heating furnace, including the following steps:

[0043] S1: Assembly preparation, several ceramic rings 7 are fitted onto the heating wire 4, and several ceramic rings 7 are respectively connected to multiple card holders 6 one by one. The fixing groove 10 side of the ceramic ring 7 faces the inner frame, so that the heating wire 4 is held in the middle section of the fixing groove 10. The end of the heating wire 4 is led out through the operation through hole 8 and connected to the power supply.

[0044] S2: Replace ceramic ring 7, open the cover plate 16 of the operating through hole 8, drive the connecting ring 12 by rotating the lever 13, and then drive all the card seats 6 to rotate along the slide groove 5. When any ceramic ring 7 passes the end of the heating wire 4, it will pass through the opening 9 of the ceramic ring 7 until the ceramic ring 7 to be replaced moves to the position of the operating through hole 8. Rotate the ceramic ring 7 so that the opening 9 side of the ceramic ring 7 faces the inner frame. Pull the ceramic ring 7 out laterally through the side wall opening 9 and replace it with a new ceramic ring 7.

[0045] S3: Replace the heating wire. Disconnect the wire connecting the end of the heating wire 4 to the power supply. Take the new heating wire 4 and fix it to one end of the old heating wire 4. That is, connect one end of the new heating wire 4 to one end of the old heating wire 4 by binding or external clamping components. Then pull the end of the old heating wire 4 outward until the new heating wire 4 is completely inserted between the inner frame 2 and the outer frame 3. Then separate the new heating wire 4 from the old heating wire 4 and connect the new heating wire 4 to the wire connecting to the power supply to complete the replacement.

[0046] S4: Uneven heating. When the thermocouple detects an abnormal temperature, the connecting ring 12 is driven by rotating the lever 13 to rotate the ceramic ring 7 in the abnormal area to the operating through hole 8. By rotating and adjusting the ceramic ring 7, the heating wire at that location is held in different limiting slots 11 according to the abnormal temperature value. Based on the different thicknesses of the fixing slots 10 at different positions, the distance between the heating wire and the vessel body is controlled.

[0047] Example 3, based on Example 2, proposes an installation requirement for the use of an adjustable pressure heating furnace.

[0048] In step S1 above, the distance between any two of the limiting slots 11 ensures that the heating wire 4 remains suspended, preventing it from touching the inner frame 2 or the outer frame 3. Specifically, regardless of which limiting slot 11 the heating wire 4 is in, the spacing between adjacent slots 6 and the ceramic ring 7 must ensure that the heating wire 4 is effectively supported and suspended throughout its entire operation, absolutely preventing any part of the heating wire 4 from directly contacting the metal inner frame 2 or the outer frame 3. Since the heating wire 4 is conductive, and the inner frame 2 will contact the vessel body, the heating wire 4 cannot contact the inner frame 2 or the outer frame 3. This prevents a short circuit caused by the heating wire 4 contacting the frame, ensuring the safe operation of the equipment.

[0049] Example 4: Based on Example 1, this example proposes a ceramic ring structure with passive adaptive adjustment function.

[0050] like Figure 5As shown, any of the limiting slots 11 is also provided with a disc spring washer 17, which is embedded in a pre-reserved recess at the bottom of the limiting slot 11. Its outer edge is fixed to the bottom of the limiting slot 11 (e.g., by high-temperature brazing or snap-fit), and its central arched part is slightly higher than the theoretical lowest point of the limiting slot 11. Specifically, the stepped fixing groove 10 based on the existing ceramic ring 7 is rigid. During the heating process of the furnace body 1, the ceramic ring 7 itself, the heating wire 4, the inner frame 2, and other materials will all undergo different degrees of thermal expansion. In particular, the coefficient of thermal expansion of the heating wire 4 (stainless steel) is much greater than that of the ceramic ring 7 (alumina ceramic). This will cause the heating wire 4 to be "tightened" or stressed in the rigid groove when it is heated and elongated. The difference in the amount of expansion of different materials may cause an unexpected slight change in the preset distance between the heating wire 4 and the furnace body (although there is a stepped groove that can be manually adjusted, it cannot respond to changes in real time). Stress accumulation may accelerate the cracking of the ceramic ring 7 or the deformation of the heating wire 4. When the heating wire 4 is inserted into the selected limiting slot 11, the heating wire 4 slightly compresses the disc spring washer 17 below it, causing it to deform and sink slightly. The disc spring washer 17 provides a slight initial preload, ensuring that the heating wire 4 is stably positioned. As the furnace temperature rises, the heating wire 4 elongates significantly due to heat. The expansion of the heating wire 4 "stretches" within the limiting slot 11. At this time, the compressed disc spring washer 17 provides a controllable elastic release space. The disc spring washer 17 passively absorbs the extra length of the heating wire 4 caused by thermal expansion, significantly reducing the thermal stress applied to the ceramic ring 7 and the heating wire 4. This utilizes the stable elasticity and limited stroke of the disc spring washer 17 at high temperatures to passively and automatically solve the problems of stress concentration and potential positional displacement caused by thermal expansion.

[0051] Example 5: Based on Example 4, this example proposes a ceramic ring structure with anti-detachment card.

[0052] like Figure 6 As shown, an anti-detachment card 18 is provided on the inner wall of the opening 9. The anti-detachment card 18 covers the opposite surfaces of the opening 9 and the limiting slot 11, and the connection between the anti-detachment card 18 and the inner wall of the ceramic ring 7 is arc-shaped. The anti-detachment card 18 is connected to the lower thickness side near the fixing slot 10. Specifically, during the adjustment and rotation of the card holder 6, in order to prevent the heating wire 4 from falling off the card holder 6 (slippage may occur in a taut state), the heating wire 4 is prevented from sliding out of the opening 9. The anti-detachment card 18 is provided to prevent the heating wire 4 from accidentally sliding out, ensuring that the heating wire 4 does not contact the inner frame 2. If the heating wire 4 falls off the limiting slot 11, the heating wire 4 can only slide off towards the lower part of the fixing slot 10. Therefore, the connecting end of the anti-detachment card 18 is connected to the lower thickness side of the fixing slot 10.

[0053] Of course, the present invention may have many other embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding changes and modifications according to the present invention, but these corresponding changes and modifications should all fall within the protection scope of the appended claims.

Claims

1. An adjustable pressure heating furnace, comprising a furnace body (1) for heating a vessel, the furnace body (1) comprising an inner frame (2) and an outer frame (3), wherein a heating wire (4) is arranged circumferentially between the inner frame (2) and the outer frame (3), characterized in that: The inner frame (2) is provided with a sliding groove (5) around the side wall. Multiple card holders (6) are slidably connected to the sliding groove (5). Several ceramic rings (7) are sleeved on the heating wire (4). The ceramic rings (7) and multiple card holders (6) are respectively connected to each other. The side wall of the outer frame (3) is provided with an operation through hole (8). The heating wire (4) is led out from the operation through hole (8) and connected to the external power supply. The inner side wall of the ceramic ring (7) is also provided with a fixing groove (10). The fixing groove (10) is arranged in a stepped structure along the inner side wall of the ceramic ring (7). Limiting slots (11) are provided at equal intervals on the fixing groove (10). The groove surface of the limiting slot (11) is the same as the diameter of the heating wire (4).

2. The adjustable pressure heating furnace according to claim 1, characterized in that: The ceramic ring (7) is a movable ceramic ring with an opening (9) on its side wall. The width of the opening (9) is the same as the diameter of the heating wire (4). The fixing groove (10) is arranged opposite to the opening (9).

3. The adjustable pressure heating furnace according to claim 1, characterized in that: Multiple card holders (6) are arranged at equal intervals and are fixedly connected by a connecting ring (12).

4. An adjustable pressure heating furnace according to claim 3, characterized in that: A rotating lever (13) is provided on the connecting ring (12), and the vertical height of the rotating lever (13) corresponds to that of the operating through hole (8).

5. An adjustable pressure heating furnace according to claim 1, characterized in that: Limiting baffles (14) are provided on both sides of the card holder (6), and the outer diameter of the ceramic ring (7) is equal to the distance between the limiting baffles (14) on both sides.

6. An adjustable pressure heating furnace according to claim 1, characterized in that: An operating through hole (8) is provided with a mounting base (15), and an operating window (1501) and an installation window (1502) are provided on the mounting base (15). The heating wire (4) passes through the installation window (1502) and is led to the outside. An openable cover plate (16) is provided on the operating window (1501).

7. An adjustable pressure heating furnace according to claim 1, characterized in that: The outer frame (3) is also provided with a thermocouple for temperature measurement, which is connected to the outside through a flexible wire.

8. A method of using an adjustable pressure heating furnace according to any one of claims 1-7, characterized in that, Includes the following steps: S1: Assembly preparation, several ceramic rings (7) are placed on the heating wire (4), several ceramic rings (7) are respectively connected to multiple card holders (6) one by one, and the fixing groove (10) side of the ceramic ring (7) faces the inner frame, so that the heating wire (4) is held in the middle section of the fixing groove (10), and the end of the heating wire (4) is led out through the operation through hole (8) and connected to the power supply; S2: Replace the ceramic ring (7), open the cover plate (16) of the operating through hole (8), drive the connecting ring (12) by rotating the lever (13), and then drive all the card holders (6) to rotate along the slide (5). When any ceramic ring (7) passes the end of the heating wire (4), it will pass through the opening (9) of the ceramic ring (7) until the ceramic ring (7) to be replaced moves to the position of the operating through hole (8). Rotate the ceramic ring (7) so that the opening (9) side of the ceramic ring (7) faces the inner frame. Pull the ceramic ring (7) out laterally through the side wall opening (9) and replace it with a new ceramic ring (7). S3: Replace the heating wire. Separate the wire connecting the end of the heating wire (4) to the power supply. Take the new heating wire (4) and fix it to one end of the old heating wire (4). That is, connect one end of the new heating wire (4) to one end of the old heating wire (4) by binding or external clamping components. Then pull one end of the old heating wire (4) outward until the new heating wire (4) is completely inserted between the inner frame (2) and the outer frame (3). Then separate the new heating wire (4) from the old heating wire (4) and connect the new heating wire (4) to the wire connecting to the power supply to complete the replacement. S4: Uneven heating. When the thermocouple detects an abnormal temperature, the connecting ring (12) is driven by rotating the lever (13) to rotate the ceramic ring (7) in the abnormal area to the operating through hole (8). By rotating and adjusting the ceramic ring (7), the heating wire in the abnormal area is held in different limiting slots (11) according to the abnormal temperature value. Based on the different thicknesses of the fixing slots (10) at different positions, the distance between the heating wire and the vessel body is controlled.

9. The method of use according to claim 8, characterized in that: In step S1 above, the distance between any two of the limiting slots (11) keeps the heating wire (4) suspended, avoiding contact with the inner frame (2) or the outer frame (3).

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