A constant temperature exhaust system for a pressure heating furnace

Abstract

The present application relates to the technical fields of semiconductor manufacturing equipment, in particular to a constant temperature exhaust system for pressure heating furnace, which comprises a heating furnace body and a heat preservation furnace chamber, the inner cavity lower end of the heat preservation furnace chamber is provided with an adsorption mechanism, the center of the adsorption mechanism is provided with a round hole which is matched with the outer diameter of the heating furnace body, a plurality of movable and openable movable furnace bottom doors are arranged on the round hole, the sidewall of the heating furnace body is provided with a plurality of guide rails along the axial direction, and the plurality of guide rails are arranged around along the axial direction of the heating furnace body. After the heating furnace body and the heat preservation furnace chamber are separated, the movable furnace bottom door automatically closes the inner cavity of the heat preservation furnace chamber, thereby reducing the risk of ammonia gas leakage to the external environment; during the lifting process of the heat preservation furnace chamber, the adsorption mechanism rotates, thereby improving the adsorption effect of activated carbon and cleaning the impurity particles accumulated on the inner wall of the heat preservation furnace chamber; in addition, the problems of slow escape rate, multiple operation steps and space occupation are solved, thereby improving the production efficiency.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor manufacturing equipment, in particular to a constant-temperature exhaust system for a pressure heating furnace. BACKGROUND

[0002] The third generation semiconductor materials (such as silicon carbide, gallium nitride, etc.) have become the core basic materials of strategic industries such as new energy vehicles, 5G communications, and energy internet due to their wide band gap, high breakdown electric field, and high thermal conductivity. The preparation process involves a high-temperature heat treatment process, which is usually carried out in a precisely controlled reaction furnace. However, harmful by-products such as ammonia and nitrogen oxides are easily produced in a high-temperature environment, which will seriously endanger the health of operating personnel and pollute the environment if leaked. In addition, the film formation quality, doping uniformity, and defect control of semiconductor crystals are highly dependent on the temperature stability and atmosphere purity of the reaction furnace, so strict requirements are put forward for the constant temperature performance of the heating system and the exhaust gas treatment.

[0003] In the prior art, considering factors such as simplicity and production cost, an electrically controlled movable stainless steel sealing cover is often provided outside the heating furnace, which is adjusted and moved to cover the outside of the heating furnace during the reaction process and removed after the reaction is completed. The main purpose of this design is: first, the density of ammonia produced during the production process is lower than that of air and it escapes upward in a high-temperature state, the cover directs the gas out through the top vent to avoid the diffusion of high-concentration ammonia to the working environment when the furnace is opened, which endangers the health and safety of workers; second, the cover can reduce the heat exchange between the furnace body and the external cold air, maintain the temperature consistency of the furnace area, thereby reducing the furnace temperature fluctuations caused by local thermal convection and improving the process stability.

[0004] However, this technology still has some deficiencies. First, passive ventilation relies on the natural upward movement of gas, which can cause ammonia to remain in the environment for too long if the escape rate is slow. Second, impurity particles (such as silicon-based dust that has not fully reacted) can accumulate inside the sealing cover, which can continue to produce ammonia under the action of residual heat if not cleaned regularly, increasing the safety hazards after production is completed. In addition, there are also problems such as long waiting time for cover movement, larger equipment volume occupying more production space, and higher frequency of cleaning and maintenance. SUMMARY

[0005] The present application provides a constant-temperature exhaust system for a pressure heating furnace to solve the above technical problems.

[0006] To achieve the above purpose, the technical solution adopted by the present application is as follows:

[0007] The application discloses a constant-temperature exhaust system for a pressure heating furnace, which comprises a heating furnace body and a heat preservation furnace chamber, the top of the heat preservation furnace chamber is provided with a hydraulic lifting rod, the bottom of the heat preservation furnace chamber is provided with an opening, the inner cavity of the heat preservation furnace chamber is provided with a space for containing the heating furnace body, the lower end of the inner cavity of the heat preservation furnace chamber is provided with an adsorption mechanism, the center of the adsorption mechanism is provided with a circular hole matched with the outer diameter of the heating furnace body, a plurality of movable and openable movable furnace bottom doors are arranged on the circular hole, the side wall of the heating furnace body is axially provided with a plurality of guide rails, and the plurality of guide rails are circumferentially arranged along the axial direction of the heating furnace body.

[0008] Further, the inner cavity wall of the heat preservation furnace chamber is circumferentially provided with a clamping groove, the periphery of the adsorption mechanism is in clamping connection with the clamping groove, and the axis of the adsorption mechanism overlaps the axis of the heat preservation furnace chamber. The adsorption mechanism is a disc structure, which is longitudinally limited in the clamping groove and can be arbitrarily rotated in the transverse direction. Before high-temperature heat treatment of the heating furnace body is carried out, the hydraulic lifting rod controls the heat preservation furnace chamber to descend, so as to close the outside of the heating furnace body, reduce heat exchange between the heating furnace body and the outside cold air, and maintain the temperature consistency of the furnace peripheral area. The size of the circular hole is matched with the outer diameter of the heating furnace body, and when the heat preservation furnace chamber descends to the lowest position, the heat preservation furnace chamber completely covers the heating furnace body, so that the heating furnace body is in a relatively constant-temperature closed cavity.

[0009] Further, the movable furnace bottom doors are provided with four, the four movable furnace bottom doors circumferentially cover the circular hole, and the movable furnace bottom doors are rotationally connected with the adsorption mechanism through torsional springs. Any movable furnace bottom door is in a sector plate structure, the movable furnace bottom door is opened during the descending process of the heat preservation furnace chamber, and the heating furnace body enters the cavity from the bottom of the movable furnace bottom door. After the heat preservation furnace chamber rises and is separated from the heating furnace body, the torsional springs restore the elastic deformation, the four movable furnace bottom doors all re-cover the circular hole, so that the heat preservation furnace chamber restores the closed chamber, and then the residual and unvolatilized ammonia gas can be prevented from escaping from the bottom of the heat preservation furnace chamber to the outside environment.

[0010] Further, the guide rails are provided with four groups, and the four groups of guide rails are arranged on the four sides of the heating furnace body. The four groups of guide rails are symmetrically arranged along the periphery of the heating furnace body and rotationally surround the vertical direction of the heating furnace body, so as to guide the rotation of the adsorption mechanism during the descending process of the heat preservation furnace chamber. This process does not need additional operation and other power equipment, reduces the use cost, and can achieve the effect of stirring the air in the heat preservation furnace chamber, accelerates the volatilization of ammonia gas and the suction effect of the exhaust device. In addition, the rotation of the adsorption mechanism can also enhance the adsorption effect of ammonia gas or waste gas, and reduce the risk of gas escaping.

[0011] Further, the plurality of movable furnace bottom doors correspond in number to the plurality of guide rails, and the bottom of each movable furnace bottom door is provided with a clamping piece that is adapted to be embedded in the guide rail. The movable furnace bottom door vertically corresponds to the guide rail, and the guide rail is provided with a baffle on both sides. The clamping piece is a strip that is arranged on the bottom surface of the connection end of the movable furnace bottom door and the adsorption structure, and the width of the strip is adapted to the width of the groove of the guide rail. During the downward movement of the holding furnace, the bottom surface of the movable furnace bottom door contacts the top surface of the heating furnace body, and at this time, the clamping piece is clamped with the upper end of the guide rail. As the holding furnace continues to move downward, the movable furnace bottom door is pushed away, and the clamping piece moves with the guide rail, causing the adsorption mechanism to rotate.

[0012] Further, the top end of the guide rail is provided with a guide groove plate that is inclined towards the central axis of the heating furnace body, and the groove of the guide groove plate is in communication with the rail of the guide rail. The inclined guide groove plate is used for guiding and guiding. In the initial stage of covering the heating furnace body during the downward movement of the holding furnace, the inclined surface of the guide groove plate can more easily guide the clamping piece at the bottom of the movable furnace bottom door to slide into the positive rail of the guide rail, improving the fault tolerance and reliability of the system operation, and avoiding hard collision.

[0013] Further, the adsorption mechanism and the movable furnace bottom door are provided with activated carbon for adsorbing ammonia gas, and the activated carbon can be detachably installed on the top surface of the adsorption mechanism and the movable furnace bottom door. Activated carbon, zeolite, ammonia-absorbing stone and other materials have the function of adsorbing ammonia gas. By arranging an activated carbon layer on the top surface of the adsorption mechanism and the movable furnace bottom door, the free ammonia gas in the holding furnace can be adsorbed, effectively capturing the ammonia gas molecules escaping from the heating furnace body, and avoiding the situation of excessive leakage of ammonia gas when the holding furnace and the heating furnace body are separated. The detachable design facilitates replacement after the activated carbon is saturated, ensuring the sustainability of the equipment operation.

[0014] Further, the top of the holding furnace is provided with an exhaust device, the exhaust device is provided with a suction pump, and the exhaust port of the exhaust device is connected with an external pipeline. The top exhaust device and the suction pump thereof constitute an active exhaust system, the suction pump provides forced air flow, the high-temperature waste gas gathered in the holding furnace and escaping upward is quickly sucked out, and is guided to an external treatment mechanism through the external pipeline. The problem of waste gas residue and slow escape caused by passive ventilation depending on natural convection is solved, and dynamic and efficient waste gas emission control is realized. Preferably, a gas concentration monitoring assembly is further arranged in the holding furnace, the gas concentration monitoring assembly is connected with the suction pump through a controller, and the gas concentration monitoring assembly is used for monitoring the gas composition and concentration in the holding furnace in real time. The monitoring signal is transmitted to the controller, and the controller dynamically adjusts the power of the suction pump according to the monitoring signal. By presetting a plurality of threshold values, the suction power of the suction pump is automatically adjusted in different threshold value ranges, and dynamic emission adjustment can be carried out according to the real-time monitoring of the ammonia concentration value. The safety of equipment use can be ensured, and energy consumption and energy can be saved.

[0015] Further, the top surface of the adsorption mechanism is provided with a scraper, and the scraper is located at the periphery of the adsorption mechanism and is arranged in close contact with the inner wall of the holding furnace. When the hydraulic lifting rod drives the holding furnace to move up and down, the adsorption mechanism rotates. At this time, not only the air can be stirred, but also the efficiency of the exhaust of the waste gas by the exhaust device can be improved, and the rotation of the scraper can be controlled. In the process of rotation of the scraper, the inner wall of the holding furnace is scraped and cleaned. Through the automatic cleaning operation of the scraper, the impurities attached to the inner wall can be cleaned before and after each operation, so that the impurities are prevented from continuously reacting to generate ammonia or blocking the air flow channel in the residual heat environment in the furnace, and the frequency and difficulty of manual cleaning are significantly reduced.

[0016] Further, the inner wall of the holding furnace is further provided with a collecting and adsorbing groove, and the collecting and adsorbing groove is located above the adsorption mechanism. A certain gap is left between the collecting and adsorbing groove and the adsorption mechanism. When the scraper scrapes and cleans along the inner wall of the holding furnace, the impurities such as dust and particulate matter attached to the inner wall are scraped off and fall into the collecting and adsorbing groove under the action of gravity. This facilitates the collection and treatment of impurities, and also avoids the secondary pollution or blockage caused by the falling of impurities on the adsorption mechanism, thereby affecting the adsorption efficiency.

[0017] Compared with the prior art, the present application has the following beneficial effects:

[0018] 1、The present application can reduce the risk of ammonia leakage to the external environment during the reaction process and after the reaction by arranging the adsorption mechanism and the movable and adjustable movable furnace bottom door, and after the heating furnace body and the holding furnace are separated, the movable furnace bottom door automatically closes the internal chamber of the holding furnace, further reducing the risk of ammonia leakage and protecting the safety of the operators;

[0019] 2、The application realizes the rotation of the adsorption mechanism in the process of lifting the heat preservation furnace by the axial surrounding guide rail and the movable furnace bottom door linkage, which not only improves the adsorption effect of activated carbon, but also cleans the impurity particles accumulated on the inner wall of the heat preservation furnace, reducing maintenance and labor costs.

[0020] 3、The application sets up the exhaust device to suck and discharge the ammonia gas volatilized upward in the high temperature working environment, and cooperates with the activated carbon at the lower part to adsorb and collect the ammonia gas, effectively reducing the ammonia gas residue, solving the problems of slow volatilization rate, many operation steps and space occupation, and further improving the production efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 is the combination structure schematic diagram of the application;

[0022] Figure 2 is the combination perspective schematic diagram of the application;

[0023] Figure 3 is the perspective schematic diagram of the heat preservation furnace;

[0024] Figure 4 is the split structure schematic diagram of the heat preservation furnace;

[0025] Figure 5 is the perspective structure schematic diagram of example four;

[0026] The figure mark: 1-heating furnace body, 2-heat preservation furnace, 3-hydraulic lifting rod, 4-adsorption mechanism, 5-round hole, 6-movable furnace bottom door, 7-guide rail, 8-clamping groove, 9-clamping piece, 10-exhaust device, 11-suction pump, 12-scraping plate, 13-collecting adsorption groove. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical scheme and advantages of the application more clear and obvious, the application is further described in detail below combined with examples and drawings, the illustrative embodiment of the application and its description are only used to explain the application, and not as the limitation of the application.

[0028] Example one, as Figures 1-4The application discloses a constant-temperature exhaust system for a pressure heating furnace, which comprises a heating furnace body 1 and a heat preservation furnace chamber 2, the top of the heat preservation furnace chamber 2 is provided with a hydraulic lifting rod 3, the bottom of the heat preservation furnace chamber 2 is provided with an opening, the inner cavity of the heat preservation furnace chamber 2 is provided with a space for accommodating the heating furnace body 1, the lower end of the inner cavity of the heat preservation furnace chamber 2 is provided with an adsorption mechanism 4, the center of the adsorption mechanism 4 is provided with a circular hole 5 matched with the outer diameter of the heating furnace body 1, a plurality of movable movable furnace bottom doors 6 are arranged on the circular hole 5 and can be opened and closed, a plurality of guide rails 7 are arranged on the side wall of the heating furnace body 1 in the axial direction, and the guide rails 7 are arranged around the heating furnace body 1 in the axial direction.

[0029] The inner cavity wall of the heat preservation furnace chamber 2 is provided with a clamping groove 8, the periphery of the adsorption mechanism 4 is connected with the clamping groove 8 in a clamping mode, and the axis of the adsorption mechanism 4 overlaps with the axis of the heat preservation furnace chamber 2. Specifically, the adsorption mechanism 4 is in a disc structure, the longitudinal direction of the adsorption mechanism 4 is limited in the clamping groove 8, and the transverse direction of the adsorption mechanism 4 can be rotated arbitrarily. Before high-temperature heat treatment of the heating furnace body 1 is carried out, the hydraulic lifting rod 3 controls the heat preservation furnace chamber 2 to descend, so as to close the outside of the heating furnace body 1, reduce heat exchange between the heating furnace body 1 and the outside cold air, and maintain the temperature consistency of the furnace area. The size of the circular hole 5 is matched with the outer diameter of the heating furnace body 1, when the heat preservation furnace chamber 2 descends to the lowest position, the heat preservation furnace chamber 2 completely covers the heating furnace body 1, so that the heating furnace body 1 is in a relatively constant-temperature closed cavity. In addition, the hydraulic lifting rod 3 and the heat preservation furnace chamber 2 are connected through a rotating shaft assembly, when the hydraulic lifting rod 3 vertically moves, the rotating shaft assembly can ensure normal rotation of the heat preservation furnace chamber 2.

[0030] The movable furnace bottom door 6 is provided with four movable furnace bottom doors 6, the four movable furnace bottom doors 6 surround the circular hole 5, and the movable furnace bottom door 6 is connected with the adsorption mechanism 4 in a rotating mode through a torsional spring. Specifically, any movable furnace bottom door 6 is in a sector plate structure, in the descending process of the heat preservation furnace chamber 2, the movable furnace bottom door 6 is opened, and the heating furnace body 1 enters the cavity from the bottom of the movable furnace bottom door 6. After the heat preservation furnace chamber 2 rises and separates from the heating furnace body 1, the torsional spring restores the elastic deformation, the four movable furnace bottom doors 6 all cover the circular hole 5 again, so that the heat preservation furnace chamber 2 restores the closed chamber, and then the residual and unvolatile ammonia gas can be prevented from escaping from the bottom of the heat preservation furnace chamber 2 to the outside environment.

[0031] The guide rail 7 is provided with four groups, and the four groups of guide rails 7 are respectively arranged on the four sides of the heating furnace body 1. Specifically, the four groups of guide rails 7 are symmetrically arranged along the four sides of the heating furnace body 1 and rotate around the vertical direction of the heating furnace body 1, for guiding the adsorption mechanism 4 to rotate during the descending process of following the holding furnace chamber 2. This process does not require additional operations and other power equipment, reduces the use cost, and at the same time can achieve the effect of stirring the air in the holding furnace chamber 2, accelerating the volatilization of ammonia gas and the adsorption effect of the exhaust device 10. In addition, the adsorption effect can also be enhanced by the rotation of the adsorption mechanism 4, reducing the risk of ammonia gas escaping.

[0032] A plurality of movable furnace bottom doors 6 correspond in number to a plurality of guide rails 7, and the bottom of the movable furnace bottom door 6 is provided with a clamping piece 9 that is adapted to be embedded with the guide rail 7. Specifically, the movable furnace bottom door 6 vertically corresponds to the guide rail 7, the guide rail 7 is a rail provided with a baffle on both sides, and the clamping piece 9 is a strip, which is arranged on the bottom surface of the connection end of the movable furnace bottom door 6 and the adsorption mechanism 4, and the width of the strip is adapted to the width of the groove of the guide rail 7. During the descending process of the holding furnace chamber 2, the bottom surface of the movable furnace bottom door 6 is in contact with the top surface of the heating furnace body 1, at which time the clamping piece 9 is correspondingly clamped with the upper end of the guide rail 7, and as the holding furnace chamber 2 continues to descend, the movable furnace bottom door 6 is pushed away, and as the clamping piece 9 moves with the guide rail 7, the adsorption mechanism 4 rotates.

[0033] The top end of the guide rail 7 is provided with a guide groove plate, which is inclinedly arranged towards the central axis of the heating furnace body 1, and the groove of the guide groove plate is in communication with the rail of the guide rail 7. Specifically, the inclinedly arranged guide groove plate is used for guiding and guiding, and in the initial stage of covering the heating furnace body 1 with the descending holding furnace chamber 2, the inclined surface of the guide groove plate can more easily guide the clamping piece 9 at the bottom of the movable furnace bottom door 6 to slide into the positive rail of the guide rail 7, improving the fault tolerance and reliability of the system operation, and avoiding hard collision.

[0034] The adsorption mechanism 4 and the movable furnace bottom door 6 are provided with activated carbon for adsorbing ammonia gas, and the activated carbon can be detachably installed on the top surface of the adsorption mechanism 4 and the movable furnace bottom door 6. Specifically, activated carbon, zeolite, ammonia absorbing stone and other materials have the functional characteristics of adsorbing ammonia gas, and the setting of the activated carbon layer on the top surface of the adsorption mechanism 4 and the movable furnace bottom door 6 can adsorb the free ammonia gas in the holding furnace chamber 2, effectively capture the ammonia gas molecules escaping from the heating furnace body 1, and avoid the situation of excessive leakage of ammonia gas when the holding furnace chamber 2 is separated from the heating furnace body 1. The detachable design facilitates replacement after the activated carbon is saturated, ensuring the sustainability of the equipment operation.

[0035] The top of the holding furnace 2 is provided with an exhaust device 10, the exhaust device 10 is provided with a suction pump 11, and the exhaust port of the exhaust device 10 is connected with the external pipeline. Specifically, the top exhaust device 10 and its suction pump 11 constitute an active exhaust system, and the suction pump 11 provides forced air flow to quickly exhaust the high-temperature waste gas (including residual ammonia gas that cannot be completely adsorbed by activated carbon and the like) accumulated in the holding furnace 2 and escaping upward, and guide it to the external treatment mechanism through the external pipeline. The problem of waste gas residue and slow escape caused by passive ventilation relying on natural convection is solved, and dynamic and efficient waste gas emission control is realized. Preferably, the holding furnace 2 is also provided with a gas concentration monitoring assembly, which is connected with the suction pump through a controller. The gas concentration monitoring assembly (such as an ammonia gas sensor) is used to monitor the gas composition and concentration inside the holding furnace 2 in real time. The monitoring signal is transmitted to the controller, and the controller dynamically adjusts the power (i.e. exhaust rate) of the suction pump 11 accordingly. By presetting multiple numerical threshold values, the suction power of the suction pump 11 is automatically adjusted within different threshold value ranges, and dynamic emission adjustment can be made according to the real-time monitored ammonia concentration value. It can not only ensure the safety of equipment use, but also save energy and energy. For example, when the ammonia concentration is detected to be high, the suction force is automatically increased to accelerate the exhaust of waste gas. When the concentration decreases to a low concentration range, the suction power can be reduced to save energy.

[0036] In example two, on the basis of example one, the specific working principle of the constant temperature exhaust system for the pressure heating furnace is proposed.

[0037] The specific implementation principle process is as follows:

[0038] Preparation operation: the heating furnace body 1 is fixedly arranged on the ground, the semiconductor material to be prepared is placed in the heating furnace body 1, and the lifting mechanism corresponding to the hydraulic lifting rod 3 is installed above the heating furnace body 1, so that the axis of the holding furnace 2 overlaps with the axis of the heating furnace body 1. The target temperature (such as 1200°C), the pressure and the heat treatment time are set by the controller, the ammonia safety threshold value (for example: ≥50ppm triggers the strong exhaust mode) of the gas concentration monitoring assembly is configured, the external treatment pipeline of the exhaust device 10 is connected, the suction pump 11 is started and waits, and the preparation process is completed.

[0039] The heat treatment process running stage: start the hydraulic lifting rod 3, drive the uniform speed of the holding furnace 2, the guide groove plate guide the bottom of the clamping piece 9 of the movable furnace bottom door 6 to slide into the guide rail 7. With the continuous downward movement of the clamping piece 9 along the guide rail 7, the heating furnace body 1 completely passes through the round hole 5 into the holding furnace inner cavity. The heating furnace body 1 is heated to the target temperature, and the semiconductor heat treatment process is started. During this process, the suction pump 11 dynamically adjusts the power according to the gas concentration monitoring data. The ammonia gas escaping upward is discharged from the exhaust port of the exhaust device 10, and the ammonia gas floating in the cavity or sinking is adsorbed by the activated carbon layer.

[0040] The process ends and separates the stage: after the process is completed, the heating furnace body 1 is cooled to a safe temperature, the hydraulic lifting rod 3 is started to lift the holding furnace 2, and the clamping piece 9 moves upward along the guide rail 7. During this process, the adsorption mechanism 4 rotates, not only can increase the efficiency of the exhaust and adsorption by stirring the waste gas, but also can scrape the inner wall of the holding furnace 2 by the scraper 12 fixed on the adsorption mechanism 4, to remove the attached silicon-based dust, to avoid the residual heat to continuously produce ammonia gas and other waste gas, and the dust and other impurities are hung and fall on the collection and adsorption groove 13. When the holding furnace 2 completely separates from the heating furnace body 1, the movable furnace bottom door 6 is closed under the action of the torsion spring, and the movable furnace bottom door 6 completely closes the round hole 5, forming an isolation chamber to avoid the residual gas escaping to the outside.

[0041] Example three, on the basis of example one, the cleaning assembly of the constant temperature exhaust system for the pressure heating furnace is provided.

[0042] The top surface of the adsorption mechanism 4 is provided with a scraper 12, which is located on the periphery of the adsorption mechanism 4 and is arranged in close contact with the inner wall of the holding furnace 2. Specifically, when the hydraulic lifting rod 3 drives the holding furnace 2 to move up and down, the adsorption mechanism 4 rotates. At this time, not only can the air be stirred to improve the efficiency of the exhaust and adsorption by the adsorption mechanism 4, but also the scraper 12 can be controlled to rotate. During the rotation of the scraper 12, the inner wall of the holding furnace 2 can be scraped and cleaned. The main reason is that the sealed environment of the holding furnace 2 is easy to accumulate impurity particles (such as silicon-based dust which is not fully reacted), and if it is not cleaned regularly, it is easy to continuously produce ammonia gas under the action of residual heat. Through the automatic cleaning work of the scraper 12, the impurities attached to the inner wall can be cleaned before and after each operation, to prevent these impurities from continuously reacting to produce ammonia gas or blocking the air flow channel in the residual heat environment of the furnace, and to significantly reduce the frequency and difficulty of manual cleaning. Preferably, the scraper 12 can be provided in an arc structure, and the convex side thereof is consistent with the rotation direction of the scraper 12, so as to improve the scraping efficiency and reduce the rotation resistance.

[0043] Example four, on the basis of example three, the cleaning and collecting assembly of the constant temperature exhaust system for the pressure heating furnace is provided.

[0044] As Figure 5 shown, the inner wall of the holding furnace 2 is also provided with a collection and adsorption groove 13, which is located above the adsorption mechanism 4. Specifically, the collection and adsorption groove 13 is of an annular structure, that is, the outer side wall of the collection and adsorption groove 13 abuts against the inner wall of the holding furnace 2, and the inner side wall of the collection and adsorption groove 13 is provided with a baffle, and water is filled in the collection and adsorption groove 13. A certain gap is left between the collection and adsorption groove 13 and the adsorption mechanism 4, and when the scraper 12 scrapes and cleans along the inner wall of the holding furnace 2, the dust, particulate matter and other impurities attached to the inner wall will be scraped off and fall into the collection and adsorption groove 13 under the action of gravity. This facilitates the collection and treatment of impurities, and also avoids the secondary pollution or blockage of the adsorption mechanism 4 caused by the falling of impurities, thereby affecting the adsorption efficiency. In addition, according to the nature of ammonia, ammonia is easily dissolved in water to form ammonia water, which is a reversible chemical equilibrium process. The solubility of ammonia in water decreases significantly with the increase of temperature, and the dissolution process is an exothermic process. Based on this, during the working process of the heating furnace body 1, the high temperature causes ammonia to overflow from the water, and the ammonia in the water is released and taken away by the exhaust device 10. After the reaction is completed, the temperature gradually decreases during the process of taking out the workpiece, and the free ammonia will be adsorbed by the water, reducing the leakage of ammonia. And the dissolution process releases heat, which can maintain the temperature in the holding furnace 2 constant, and the heat preservation is beneficial to the subsequent process flow, reducing the power consumption of the heating furnace body 1.

[0045] In summary, the collection and adsorption groove 13 is used to carry water and collect scraped impurities, and the water can collect free ammonia after the reaction is completed to avoid escape, and can also release heat to maintain the temperature in the holding furnace 2 constant, reducing the energy consumption of the heating furnace body 1 in the next process step. During the reaction process, the high temperature causes the saturated water to release ammonia, which is taken away by the exhaust device 10.

[0046] Of course, the present application can have other various embodiments, and those skilled in the art can make various corresponding changes and modifications according to the present application without departing from the spirit and essence of the present application, but these corresponding changes and modifications should all belong to the protection scope of the claims attached to the present application.

Claims

1. A constant temperature exhaust system for a pressure heating furnace, comprising a heating furnace body (1) and a heat preservation furnace chamber (2), a hydraulic lifting rod (3) is installed at the top of the heat preservation furnace chamber (2), an opening is arranged at the bottom of the heat preservation furnace chamber (2), and the inner cavity of the heat preservation furnace chamber (2) is provided with a space for accommodating the heating furnace body (1), characterized in that: The inner cavity lower end of the holding furnace (2) is provided with an adsorption mechanism (4), the center of the adsorption mechanism (4) is provided with a circular hole (5) matched with the outer diameter of the heating furnace body (1), a plurality of movable opening and closing movable furnace bottom doors (6) are arranged on the circular hole (5), a plurality of guide rails (7) are arranged on the side wall of the heating furnace body (1) along the axial direction, a plurality of guide rails (7) are arranged around the heating furnace body (1) along the axial direction, the inner cavity wall of the holding furnace (2) is provided with a clamping groove (8), the periphery of the adsorption mechanism (4) is embeddedly connected with the clamping groove (8), the bottom of the movable furnace bottom door (6) is provided with a clamping piece (9) matched with the guide rail (7), the top surface of the adsorption mechanism (4) is provided with a scraper (12), the scraper (12) is located on the periphery of the adsorption mechanism (4) and is arranged in close contact with the inner wall of the holding furnace (2). ​ 2. A thermostatic exhaust system for a pressure heating furnace according to claim 1, characterized in that: The axis of the adsorption mechanism (4) overlaps with the axis of the holding furnace (2).

3. A thermostatic exhaust system for a pressure heating furnace according to claim 1, characterized in that: The movable furnace bottom door (6) is provided with four, four movable furnace bottom doors (6) cover the circular hole (5), the movable furnace bottom door (6) is rotatably connected with the adsorption mechanism (4) through a torsion spring.

4. A thermostatic exhaust system for a pressure heating furnace according to claim 3, characterized in that: The guide rail (7) is provided with four groups, and four groups of guide rails (7) are arranged on the four sides of the heating furnace body (1).

5. A thermostatic exhaust system for a pressure heating furnace according to claim 4, characterized in that: A plurality of movable furnace bottom doors (6) correspond in number to a plurality of guide rails (7).

6. A thermostatic exhaust system for a pressure heating furnace according to claim 1, characterized in that: The top end of the guide rail (7) is provided with a guide groove plate, the guide groove plate is inclinedly arranged towards the center axis of the heating furnace body (1), and the groove of the guide groove plate is in communication with the rail of the guide rail (7).

7. A thermostatic exhaust system for a pressure heating furnace according to claim 1, characterized in that: The adsorption mechanism (4) and the movable furnace bottom door (6) are provided with activated carbon for adsorbing ammonia, and the activated carbon can be detachably installed on the top surface of the adsorption mechanism (4) and the movable furnace bottom door (6).

8. A thermostatic exhaust system for a pressure heating furnace according to claim 1, characterized in that: The top of the holding furnace (2) is provided with an exhaust device (10), the exhaust device (10) is provided with a suction pump (11), and the exhaust port of the exhaust device (10) is connected with an external pipeline.

9. A thermostatic exhaust system for a pressure heating furnace according to claim 1, wherein: The inner wall of the holding furnace (2) is also provided with a collecting and adsorbing groove (13) around, and the collecting and adsorbing groove (13) is located above the adsorption mechanism (4).

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