Energy-saving numerical control tempering furnace
By employing a multi-compartment design and automated control of the top-pushing mechanism, combined with an integrated waste gas treatment system, the problems of high energy consumption, large footprint, and low automation in large tempering furnaces have been solved, enabling efficient, energy-saving, and environmentally friendly continuous production of small metal parts.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- AUBEN INTELLIGENT EQUIP TECH (HANGZHOU) CO LTD
- Filing Date
- 2025-08-22
- Publication Date
- 2026-07-07
AI Technical Summary
Existing large-scale tempering furnaces are energy-intensive, occupy a large area, have low automation, and cause serious environmental pollution, making it difficult to meet the needs of efficient, energy-saving, environmentally friendly, and continuous production of small metal parts.
It adopts a multi-compartment design and uses a top-pushing mechanism to realize the automatic opening and closing of the partitions. Combined with the integrated waste gas treatment system, the mechanical movement of the top-pushing block and the swing arm is driven by a single power source to achieve seamless transfer of workpieces and efficient purification of waste gas.
It enables efficient, energy-saving, and environmentally friendly continuous production of small metal parts, reduces equipment costs and failure rates, improves production efficiency, and reduces environmental pollution.
Smart Images

Figure CN224467850U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of heat treatment equipment technology, specifically to an energy-saving CNC tempering furnace. Background Technology
[0002] Tempering of metal workpieces is a crucial step in eliminating internal stress and stabilizing the microstructure. Currently, mainstream large-scale tempering furnaces suffer from high power consumption and large footprint, making them unsuitable for producing small parts such as small hardware and springs. Specifically, they present the following pain points: 1. High energy consumption: Starting and maintaining large equipment requires significant energy, resulting in extremely low energy efficiency when processing small batches of workpieces, failing to meet energy-saving production requirements. 2. Low automation: The tempering process requires multiple steps and repeated manual transfers between different furnaces, leading to cumbersome procedures and low production efficiency. 3. Large space occupation: The bulky equipment structure is unsuitable for the spatial layout of small and medium-sized production enterprises. 4. Environmental pollution: Most traditional equipment directly discharges the generated organic waste gas, polluting the environment.
[0003] To address the aforementioned issues, some improved equipment has emerged on the market. For example, patent application number 202110411375.7, entitled "A Well-Type Multi-Chamber Continuous Heat Treatment Tempering Furnace," describes a multi-chamber design where each chamber door is equipped with a separate motor and transmission gears to achieve independent opening and closing of each partition. While this solution achieves continuous feeding and reduces floor space to some extent, its transmission and control structure is complex. Each chamber door requires independent drive and actuator components, resulting in high costs, numerous potential failure points, and inconvenient maintenance. Furthermore, the simultaneous operation of multiple motors increases energy consumption, and waste gas collection and treatment are typically relatively simple, leaving considerable room for improvement in energy-saving and environmental benefits. Utility Model Content
[0004] The technical problem to be solved by this utility model is to overcome the above-mentioned problems and provide an energy-saving CNC tempering furnace with a compact structure, low energy consumption, and high degree of automation, which can meet the needs of efficient, energy-saving, and environmentally friendly continuous heat treatment production of small metal parts.
[0005] The technical solution of this utility model is:
[0006] The present invention discloses an energy-saving CNC tempering furnace, comprising a furnace body, wherein the furnace body includes a feeding bin, multiple processing bins, and a discharging bin arranged sequentially from top to bottom, and adjacent bins are separated by a set of splittable partitions, characterized in that:
[0007] Each partition is fixed with a rotating shaft, one end of which is fixedly connected to a swing arm, and the other end of the swing arm is provided with a contact part.
[0008] The furnace body is equipped with a push mechanism that can slide up and down. The push mechanism includes a push slide, a limiting block that can slide up and down on the push slide, and two push blocks that can slide horizontally on the push slide. The push blocks can move upward with the push mechanism and push against the contact part of the swing arm to open the partition. The limiting block is located between the two push blocks, and a linkage structure is also provided between the limiting block and the push blocks.
[0009] The limiting block is configured such that: when its lower end touches the bottom of the furnace body, it moves upward, and through the linkage structure, it pushes the two push blocks to slide back to back to a position that can contact the contact part of the swing arm; when its upper end touches the top of the furnace body, it moves downward, and through the linkage structure, it causes the two push blocks to reset and slide towards each other without interfering with the contact part.
[0010] In this structure, the pushing mechanism is initially located at the bottom of the furnace body. The limiting block contacts the bottom and, under the action of the linkage structure, pushes the two pushing blocks into a "prepared state" where they slide out in opposite directions, i.e., a position where they can contact the contact parts of each layer's swing arms. As the pushing mechanism rises, the pushing blocks collide with and push against the contact parts of each layer's partition swing arm from bottom to top, causing the swing arm to swing and drive the partition to rotate around its axis and open, allowing the workpiece to fall layer by layer. As the pushing mechanism continues to rise, the pushing blocks disengage from the contact parts of the swing arm of the current layer, and the partition of that layer automatically closes to catch the workpiece falling from the upper layer. The mechanism rises and repeats this process until the workpiece finally falls into the discharge hopper.
[0011] When the jacking mechanism rises to the top of the furnace body, the upper end of the limiting block abuts against the furnace top. This abutting force forces the limiting block to move downward relative to the jacking slide, and through the linkage structure, drives the two jacking blocks to slide towards each other and retract to the "avoidance state".
[0012] The pusher mechanism moves downwards back to the bottom of the furnace body. During this process, the pusher block will not come into contact with or interfere with any of the swing arms that are in the closed state, and the partition remains closed.
[0013] Furthermore, in the energy-saving CNC tempering furnace described in this utility model, the linkage structure is an inclined structure that gradually expands from top to bottom on the opposite sides of the limiting block and the pushing block. This inclined structure efficiently converts the vertical movement of the limiting block into the horizontal movement of the pushing block, resulting in high transmission efficiency, rapid action response, and effective switching between the ejection and retraction states.
[0014] Furthermore, in the energy-saving CNC tempering furnace described in this utility model, the upper and lower ends of the inclined surface are respectively provided with slots for the push block to be engaged. The slot design can provide positioning and holding force when the push block moves to the upper and lower limit positions, preventing movement due to vibration or external interference during the pushing process, and ensuring the accuracy and stability of the pushing operation.
[0015] Furthermore, in the energy-saving CNC tempering furnace described in this utility model, a first return spring is provided between the two push blocks. The first return spring provides the push blocks with the driving force to return to their original position, ensuring that the push blocks can quickly and reliably retract towards each other when the limit block moves down, ensuring that the push mechanism will never accidentally touch the swing arm during the descent process, and the working process is reliable.
[0016] Furthermore, in the energy-saving CNC tempering furnace described in this utility model, a second return spring is provided between the end of the swing arm near the contact portion and the furnace body. The second return spring is used to provide an automatic closing torque for the swing arm and the partition after the push block separates from the swing arm, ensuring that the partition can be closed tightly in a timely manner, maintaining the airtightness of each compartment, and reducing heat loss.
[0017] Furthermore, in the energy-saving CNC tempering furnace described in this utility model, the top pushing mechanism is connected to a driving mechanism for driving its upward and downward sliding.
[0018] Preferably, the drive mechanism includes a motor and a sprocket and chain assembly, and the push slide is fixed on the chain of the sprocket and chain assembly.
[0019] Furthermore, in the energy-saving CNC tempering furnace described in this utility model, the processing chamber includes multiple heating chambers and an insulation chamber located between the feeding chamber and the uppermost heating chamber. The insulation chamber forms an effective thermal barrier between the high-temperature zone and the feeding chamber, significantly blocking the upward transfer of heat and preventing excessively high temperatures at the feed inlet. This improves the operating environment, significantly reduces heat loss during feeding, and enhances the overall energy efficiency of the machine.
[0020] Furthermore, in the energy-saving CNC tempering furnace described in this utility model, the furnace body is provided with a waste gas treatment device, which includes a gas collecting mechanism disposed below the feeding hopper, a filtration mechanism connected to the gas collecting mechanism, and an exhaust mechanism connected to the filtration mechanism.
[0021] Preferably, the gas collection mechanism is a cover plate located at the bottom of the feed hopper. The cover plate is hollow, forming an extraction chamber. A through-feed inlet is located in the center of the cover plate. The extraction chamber is connected to the feed hopper through multiple extraction holes arranged around the inlet. The filtration mechanism includes an extraction channel and an activated carbon box located on the inner wall of the furnace body. The extraction chamber, extraction channel, and activated carbon box are sequentially connected. The exhaust mechanism includes a fan located at the bottom of the furnace body and an exhaust channel vertically located on the inner wall of the furnace body. The fan inlet is connected to the activated carbon box outlet, and the fan outlet is connected to the bottom of the exhaust channel. The generated waste gas, under the negative pressure inside the furnace, enters the integrated waste gas treatment device through the extraction holes at the bottom of the feed hopper and is discharged after purification.
[0022] The beneficial effects of this utility model are:
[0023] 1. This utility model ingeniously utilizes a jacking mechanism driven by a single power source. Through the cyclical mechanical motion of rising and pushing and falling to avoid obstacles, combined with the pure mechanical limit triggers at the top and bottom ends, it precisely controls the sequential opening and closing of all multi-layer partitions and the transfer of workpieces. It abandons the complex scheme of configuring a motor and transmission components for each compartment door in the existing technology, simplifies the overall structure, reduces the number of parts, not only reduces manufacturing costs and failure rate, but also improves the reliability and service life of the equipment, while significantly reducing the energy consumption of the transmission system itself.
[0024] 2. This utility model adopts a multi-compartment design and automatically opens and closes the partitions between each layer through the cyclic up-and-down movement of the push mechanism. This allows the workpiece to be transferred step by step between the feeding compartment, multiple processing compartments and the discharge compartment. The whole process does not require manual intervention and realizes seamless connection and continuous flow operation of the entire process of "feeding-processing-discharging". It solves the waiting time problem of traditional batch furnaces and the efficiency bottleneck of intermittent feeding of similar equipment. It is especially suitable for large-volume, high-efficiency continuous production of small workpieces.
[0025] 3. This utility model highly integrates the waste gas collection, filtration, and emission system inside the furnace body. Utilizing the principle of natural upward flow of hot waste gas, it efficiently collects it into a negative pressure-driven collection system near the feed inlet. After purification by built-in activated carbon filtration, the waste gas is discharged, avoiding environmental pollution. Simultaneously, this integrated treatment method reduces reliance on external pipelines, features a compact layout, and avoids heat loss caused by direct discharge of conventional waste gas. Attached Figure Description
[0026] Figure 1 This is a schematic diagram of the overall structure of this utility model.
[0027] Figure 2 This is a partial structural schematic diagram of the present invention.
[0028] Figure 3 for Figure 2 A magnified view of a portion of the image.
[0029] Figure 4 for Figure 2 Schematic diagram of the structure after the feed hopper is removed Figure 1 .
[0030] Figure 5 for Figure 2 Schematic diagram of the structure after the feed hopper is removed Figure 2 .
[0031] In the diagram: 1. Furnace body; 2. Feeding bin; 3. Insulation bin; 4. Heating bin; 5. Discharge bin; 6. Partition plate; 7. Rotating shaft; 8. Swing arm; 9. Contact part; 10. Pushing slide; 11. Limiting block; 12. Pushing block; 13. Bearing; 14. First return spring; 15. Second return spring; 16. Slot; 17. Motor; 18. Sprocket and chain assembly; 19. Cover plate; 20. Air extraction hole; 21. Air extraction channel; 22. Activated carbon box; 23. Fan; 24. Air outlet channel. Detailed Implementation
[0032] The present invention will now be further described with reference to the accompanying drawings:
[0033] Reference Figures 1-2 As shown in the figure, the energy-saving CNC tempering furnace described in this embodiment includes a furnace body 1. The furnace body 1 includes a feeding bin 2, multiple processing bins, and a discharging bin 5 arranged sequentially from top to bottom. The processing bins include three heating bins 4 and an insulated bin 3 located between the feeding bin 2 and the uppermost heating bin 4. Adjacent bins are separated by a set of split-opening partitions 6 to achieve the independence and sealing of each functional bin.
[0034] The feeding hopper 2 is equipped with a tiltable and adjustable feeding hopper. The discharging hopper 5 is equipped with a retractable and extendable discharging hopper, which can be retracted when not in use, saving space. Each heating chamber 4 is equipped with heating rods (or heating wires), temperature sensors, etc., and the temperature of each heating chamber 4 can be controlled by connecting to the tempering furnace control system. The heat insulation chamber 3 is designed to effectively prevent heat leakage from the high-temperature area and avoid burns. In addition, the outer walls of each chamber are covered with heat insulation cotton to effectively reduce heat loss and prevent the machine from overheating.
[0035] Reference Figure 2 and Figure 3 Each partition 6 is fixedly equipped with a rotating shaft 7. One end of the rotating shaft 7 is fixedly connected to a swing arm 8, and the other end of the swing arm 8 has a protruding contact portion 9, preferably a roller structure, to reduce friction. A second return spring 15 is provided between the end of the swing arm 8 near the contact portion 9 and the furnace body 1. The tension of this spring always makes the swing arm 8 tend to rotate the partition 6 towards the closed position, ensuring that the partition 6 is in a sealed state when there is no external force intervention.
[0036] The furnace body 1 is equipped with a sliding push mechanism, which is the core actuator driving the sequential opening and closing of all partitions 6. The push mechanism includes a push slide 10, a limiting block 11 sliding on the push slide 10, and two push blocks 12 sliding horizontally on the push slide 10. The push mechanism is connected to a drive mechanism for driving its upward and downward movement. Specifically, the drive mechanism includes a motor 17 and a sprocket and chain assembly 18, with the push slide 10 fixed to the chain of the sprocket and chain assembly 18. The push blocks 12 can move upward with the push mechanism and engage with the contact portion 9 of the swing arm 8 to open the partitions 6. A first return spring 14 is provided between the two push blocks 12, and the tension of this spring causes the two push blocks 12 to tend to move closer together.
[0037] The limiting block 11 is located between the two pushing blocks 12, and a linkage structure is provided between the limiting block 11 and the pushing blocks 12. The linkage structure is an inclined surface structure that gradually expands from top to bottom on the opposite sides of the limiting block 11 and the pushing blocks 12. A bearing 13 is installed on the side of the pushing block 12 facing the limiting block 11 to reduce the motion friction between the two. The upper and lower ends of the inclined surface are respectively provided with slots 16 for the bearings 13 of the pushing blocks 12 to be engaged. The slots 16 play a positioning and holding role to prevent the pushing blocks 12 from moving accidentally in the non-switching state.
[0038] The limiting block 11 is configured such that: when its lower end touches the bottom of the furnace body 1, it moves upward, pushing the two push blocks 12 to slide back-to-back to a position where they can contact the contact part 9 of the swing arm 8, at which point the bearing 13 is locked into the groove 16 at the lower end of the slope. When its upper end touches the top of the furnace body 1, it moves downward, causing the two push blocks 12 to return to their original position and slide back without interfering with the contact part 9 of the swing arm 8, at which point the bearing 13 of the push block 12 is locked into the groove 16 at the upper end of the slope.
[0039] In this embodiment, the opening of each set of partitions 6 adopts a counter-axis swing method. To ensure that each set of double-opening partitions 6 can open and close smoothly and reliably, the heights of the contact surfaces between the two push blocks 12 and the contact parts 9 of the swing arm 8 are different. The height difference enables the time-sharing action of the two partitions 6. The higher push block 12 pushes one side of the partition 6 to open first, and then the lower push block 12 pushes the other side of the partition 6 to move. This achieves the first-open-first-close mechanism, improves the smoothness of opening, effectively reduces the torque required for the two door panels to start at the same time, and avoids motion interference and mechanism jamming.
[0040] Reference Figure 4 and Figure 5The furnace body 1 is equipped with a waste gas treatment device, which includes a gas collection mechanism located below the feed hopper 2, a filtration mechanism connected to the gas collection mechanism, and an exhaust mechanism connected to the filtration mechanism. Specifically, the gas collection mechanism is a cover plate 19 located at the bottom of the feed hopper 2. The cover plate 19 is hollow to form an extraction chamber, and a through-feed inlet is opened in the middle of the cover plate 19. The extraction chamber is connected to the feed hopper 2 through multiple extraction holes 20 arranged around the inlet. The filtration mechanism includes an extraction channel 21 and an activated carbon box 22 located on the inner wall of the furnace body 1. The extraction chamber, the extraction channel 21, and the activated carbon box 22 are connected in sequence. The activated carbon box 22 adopts a detachable drawer-type design for easy replacement. The exhaust mechanism includes a fan 23 located at the bottom of the furnace body 1 and an exhaust channel 24 vertically located on the inner wall of the furnace body 1. The air inlet of the fan 23 is connected to the outlet of the activated carbon box 22, the air outlet of the fan 23 is connected to the bottom of the exhaust channel 24, and the top of the exhaust channel 24 can be connected to the workshop return air pipe.
[0041] The entire work process is as follows:
[0042] Initial state: Before equipment startup, all partitions 6 are closed under the action of their respective second return springs 15. The pushing mechanism is at the bottom of the furnace body 1. At this time, the lower end of the limiting block 11 abuts against the bottom of the furnace body 1, forcing the pushing block 12 to overcome the tension of the first return spring 14, slide outward to the "push out" ready state, and be locked by the slot 16. The operator puts the workpiece to be processed into the feeding bin 2 through the feeding hopper, and the workpiece is temporarily piled on the top layer of closed partitions 6. Each heating chamber 4 has been heated to the preset tempering temperature.
[0043] Pushing and Lifting: The control system starts the drive motor 17, which drives the pushing mechanism to rise via the sprocket and chain assembly 18. During the lifting process: When the pushing block 12 rises to the contact part 9 of the lowest partition 6, a collision and push occur. The pushing force overcomes the tension of the second return spring 15, driving the swing arm 8 to swing, thereby causing the partition 6 to rotate and open around the pivot 7. The workpiece that was originally on the partition 6 then falls into the discharge bin 5 below.
[0044] The pushing mechanism continues to rise, and the pushing block 12 immediately disengages from the contact part 9 of the current layer. The partition 6 of this layer immediately and automatically resets and closes under the action of the second reset spring 15.
[0045] The jacking mechanism rises sequentially in this manner, opening each partition 6 briefly from bottom to top, layer by layer. As a result, the workpiece originally located on the upper layer falls into the lower layer chamber the instant the partition 6 below it opens. Each workpiece undergoes a set holding time in each heating chamber 4, achieving continuous segmented processing.
[0046] Top Switching: When the push mechanism rises to the highest point of the furnace body 1, the upper end of the limiting block 11 abuts against the furnace top. This abutting force forces the limiting block 11 to move downward relative to the push slide 10. This downward movement, through the cooperation of the inclined surface and the slot 16, releases the locking and constraint on the push block 12. Under the pulling force of the first return spring 14, the two push blocks 12 quickly slide towards each other, retract to the "avoidance" state, and are locked by the upper slot 16.
[0047] The jacking mechanism descends: Subsequently, the drive motor 17 reverses, causing the jacking mechanism to descend. Since the jacking block 12 is already in the retracted state, its outline is completely outside the movement trajectory of the contact part 9. Therefore, throughout the descent, the jacking block 12 will not contact or interfere with the swing arms 8 of any of the closed partitions 6, and all partitions 6 remain tightly closed. The jacking mechanism descends smoothly to the bottom of the furnace body 1.
[0048] Bottom reset: When the pusher mechanism reaches the bottom of the furnace body 1 again, the lower end of the limit block 11 touches the bottom again, repeating the process of the initial state, pushing the pusher block 12 to slide outward, switching to the "push out" preparation state, and preparing for the next working cycle.
[0049] Waste gas treatment: During the entire heat treatment process, due to the natural upward effect of hot air, the waste gas will accumulate in the feed hopper 2 area at the top of the furnace body 1. The blower 23 located at the bottom of the furnace works continuously, creating a negative pressure in the system, which draws the waste gas into the extraction chamber from the extraction hole 20 at the bottom of the feed hopper 2, and then flows through the extraction channel 21 and the activated carbon box 22 in sequence. The harmful components in the waste gas are adsorbed and purified by the activated carbon, and the clean gas is finally drawn into the exhaust channel 24 by the blower 23 and discharged into the atmosphere.
[0050] Discharge: After a complete heat treatment cycle, the workpieces that finally fall into discharge hopper 5 have been processed. Operators can periodically or continuously remove finished workpieces from the discharge hopper.
[0051] This completes a full automated work cycle. The entire process requires no manual handling of workpieces, achieving fully automated continuous operation from feeding, multi-layer segmented heat treatment, to discharging.
[0052] In this structure, the furnace body 1 is equipped with handrails, and the bottom of the furnace body 1 is equipped with casters, including one omnidirectional caster and two directional casters, to facilitate workshop adjustments and ensure convenient and stable movement, guaranteeing the stability of the machine at all times. A display and operation panel is also installed on top of the furnace body 1, integrated with the feeding hopper 2.
[0053] The specific embodiments described herein are merely illustrative of the principles and effects of this utility model and are not intended to limit the scope of this utility model. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of this utility model. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this utility model are still covered by the claims of this utility model.
Claims
1. An energy-saving numerical control tempering furnace, comprising a furnace body, the furnace body comprising, from top to bottom, a feeding bin, a plurality of processing bins and a discharging bin, each adjacent bin being separated by a set of openable partitions, characterized in that: each partition is fixed with a rotating shaft, one end of the rotating shaft being fixedly connected with a swing arm, the other end of the swing arm being provided with a contact portion; a pushing mechanism is arranged in the furnace body and can slide up and down, the pushing mechanism comprising a pushing slide table, a limiting block arranged on the pushing slide table and capable of sliding up and down, and two pushing blocks arranged on the pushing slide table and capable of sliding horizontally; the pushing blocks can be pushed by the contact portion of the swing arm to open the partitions when the pushing mechanism moves upward; the limiting block is located between the two pushing blocks and a linkage structure is further arranged between the limiting block and the pushing blocks; the limiting block is configured to move upward when its lower end abuts against the bottom of the furnace body, push the two pushing blocks to slide away from each other to a position where they can contact the contact portion of the swing arm through the linkage structure, and move downward when its upper end abuts against the top of the furnace body, so that the two pushing blocks slide back to the original position through the linkage structure and do not interfere with the contact portion.
2. The energy efficient numerical controlled tempering furnace as claimed in claim 1, wherein: The linkage structure is a slope structure formed on the opposite sides of the limiting block and the pushing blocks and gradually expanding from top to bottom.
3. The energy efficient numerical controlled tempering furnace as claimed in claim 2, wherein: The upper end and the lower end of the slope are respectively provided with a clamping groove for clamping the pushing blocks.
4. The energy efficient numerical controlled tempering furnace as claimed in claim 1 wherein: A first return spring is arranged between the two pushing blocks.
5. The energy efficient numerical controlled tempering furnace as claimed in claim 1 wherein: A second return spring is arranged between the end of the swing arm close to the contact portion and the furnace body.
6. The energy efficient numerical controlled tempering furnace as claimed in claim 1 wherein: The pushing mechanism is connected with a driving mechanism for driving the pushing mechanism to slide up and down.
7. The energy efficient CNC tempering furnace as claimed in claim 6, wherein: The driving mechanism comprises a motor and a chain wheel and chain assembly, and the pushing slide table is fixed on the chain of the chain wheel and chain assembly.
8. The energy efficient numerical controlled tempering furnace as claimed in claim 1 wherein: The processing bin comprises a plurality of heating bins and a heat insulation bin arranged between the feeding bin and the uppermost heating bin.
9. The energy efficient numerical controlled tempering furnace as claimed in claim 1 wherein: A waste gas treatment device is arranged in the furnace body, the waste gas treatment device comprising a gas collecting mechanism arranged below the feeding bin, a filtering mechanism in communication with the gas collecting mechanism, and an exhaust mechanism in communication with the filtering mechanism.
10. The energy efficient computer numerically controlled tempering furnace of claim 9, wherein: The gas collecting mechanism is a cover plate arranged at the bottom of the feeding bin, the cover plate being hollow to form an air extraction chamber, the cover plate being provided with a feeding port penetrating from top to bottom in the middle, and the air extraction chamber being in communication with the feeding bin through a plurality of air extraction holes arranged around the feeding port; the filtering mechanism comprises an air extraction channel arranged on the inner wall of the furnace body and an activated carbon box, the air extraction chamber, the air extraction channel and the activated carbon box being in sequence; the exhaust mechanism comprises a fan arranged at the bottom of the furnace body and an air outlet channel arranged vertically on the inner wall of the furnace body, the air inlet of the fan being in communication with the outlet of the activated carbon box, and the air outlet of the fan being in communication with the bottom of the air outlet channel.