EP4040096A1

EP4040096A1 - Tunnel kiln and conveying method

Info

Publication number: EP4040096A1
Application number: EP21878744.8A
Authority: EP
Inventors: Xia Wang; Zhen Wu
Original assignee: Cinoapex Thermo Tech Suzhou Co Ltd; Cinoapex Thermo Technology Suzhou Co Ltd
Current assignee: Cinoapex Thermo Tech Suzhou Co Ltd; Cinoapex Thermo Technology Suzhou Co Ltd
Priority date: 2020-12-01
Filing date: 2021-07-15
Publication date: 2022-08-10
Also published as: EP4040096A4; WO2022116546A1; KR20220079891A

Abstract

A tunnel kiln and a conveying method belong to the field of processing for lithium-ion battery materials. The tunnel kiln comprises a kiln body (4), a first gas replacement chamber (24), a second gas replacement chamber (25), gates, and a gas-tight housing. The first gas replacement chamber (24) is in connection with the second gas replacement chamber (25) via the kiln body (4), and gates are respectively provided at the inlets of the two gas replacement chambers and at the joints of the two and the kiln body. The kiln body (4), the gates, and the two gas replacement chambers are in cooperative connection with each other. Interference caused by external gas can be effectively controlled through this device, so as to assure normal and orderly proceeding of thermal treatment or thermochemical treatment operations.

Description

Cross-reference to Related Application

The present disclosure claims the priority to the Chinese patent application filed with the Chinese Patent Office on December 1, 2020 with the filing No. 2020113995761 and entitled "Tunnel Kiln and Conveying Method", and to the Chinese patent application filed with the Chinese Patent Office on December 1, 2020 with the filing No. 202022854325X and entitled "Tunnel Kiln", all the contents of which are incorporated herein by reference in entirety.

Technical Field

The present disclosure relates to the field of processing for lithium-ion battery materials, and particularly to a tunnel kiln and a conveying method.

Background Art

At present, the production of positive electrode (cathode) active materials for lithium-ion batteries generally involves thermal treatment or thermochemical treatment, especially a procedure of high-temperature calcination. Therefore, relevant production enterprises have been looking for new apparatuses and new methods for increasing the calcination capacity of cathode materials, so as to improve production efficiency and reduce the production cost of cathode materials.
At present, the apparatus for implementing high-temperature calcination is generally a continuous tunnel kiln. Continuous tunnel kilns can be divided into different types such as pusher-plate type, roller type and car convey (wheel-track) type. They are capable of continuous producing for twenty-four hours and therefore have a higher production capacity than batch kilns.
In the above, due to great resistance of the propulsion manner, pusher-plate type tunnel kilns have relatively short effective heating length and thus have limited potential for production capacity improvement; and roller-type tunnel kilns have relatively high requirements on the mechanical strength and the high-temperature stability of rollers or the like, and the rollers are easy to deform under high-temperature load, thus, the potential for further increasing the production capacity is also limited. The defects of the both can be fundamentally avoided by car convey (wheel-track) tunnel kilns; thus, car convey tunnel kilns have a greater production capacity improving potential. However, as for cathode materials requiring strict control over high-temperature calcination atmosphere, gas outside the car convey tunnel kilns would interfere with the calcination atmosphere inside the tunnel kiln, due to poor gas tightness of the car convey tunnel kilns. Thus, existing car convey tunnel kilns cannot be effectively suitable for production of cathode materials.

Summary

In order to solve the above problem of the gas outside the car convey tunnel kilns interfering with the internal atmosphere, a tunnel kiln and a conveying method are proposed in the present disclosure.
The present disclosure is implemented as follows.
An embodiment of the present disclosure provides a tunnel kiln, comprising a kiln vehicle (car), a kiln body, a first gas replacement chamber, a second gas replacement chamber, and gates configured to be able to be selectively opened or closed.
In the above, the kiln body has an internally located tunnel, and the tunnel is provided with a track. The first gas replacement chamber has a first inlet and a first outlet. The first gas replacement chamber is in connection with an end of the kiln body via the first outlet. The second gas replacement chamber has a second inlet and a second outlet. The second gas replacement chamber is in connection with the other end of the kiln body via the second inlet. The first inlet, the first outlet, the second inlet, and the second outlet are each provided with a gate. The kiln vehicle is configured to be able to pass through the first gas replacement chamber, the kiln body, and the second gas replacement chamber.
Optionally, the tunnel kiln comprises a gas-tight housing, and this gas-tight housing wraps the kiln body, the first gas replacement chamber, and the second gas replacement chamber.
Optionally, the gas-tight housing is formed by welding a steel structural frame and a prefabricated sheet metal component.
Optionally, an independent first transfer mechanism cooperating with the track and a first driving mechanism configured to drive the movement of the kiln vehicle are provided in the first gas replacement chamber, and an independent second transfer mechanism cooperating with the track and a second driving mechanism configured to drive the movement of the kiln vehicle are provided in the second gas replacement chamber.
Optionally, two ends of the kiln body tunnel are able to be separably docked respectively with the first transfer mechanism and the second transfer mechanism.
Optionally, the tunnel kiln comprises the kiln vehicle, which is able to selectively move in any one of the first transfer mechanism, the second transfer mechanism, and the kiln body track.
Optionally, the first gas replacement chamber and the second gas replacement chamber are each provided therein with a damping mechanism cooperating with the kiln vehicle.
Optionally, the first gas replacement chamber is provided therein with a preheating device.
Optionally, the second gas replacement chamber is provided therein with a cooling device.
Optionally, a side wall of the kiln body is provided with a heater.
Optionally, a side wall of the kiln body is provided with a gas injection port.
Optionally, one or more temperature sensors are arranged in the kiln body.
Optionally, the first gas replacement chamber and the second gas replacement chamber are respectively independently equipped with a vacuum device.
Optionally, the lower part of the kiln vehicle is provided with vehicle wheels, and the kiln vehicle moves on the track through rolling of the vehicle wheels.
Optionally, the track is a U-shaped structural track or a pit track.
Optionally, a pair of guide tracks are arranged at the bottom of the kiln vehicle, while two columns of fixed roller sets are mounted at the bottom of the kiln, and the kiln vehicle is enabled to travel forward inside the kiln body through the movement of the guide tracks on the roller sets.
An embodiment of the present disclosure provides a conveying method, which is implemented through the tunnel kiln as described above.
The conveying method comprises:

providing an operation environment inside the tunnel of the kiln body, when the first outlet and the second inlet are in a closed state;
transferring a carrier outside the tunnel kiln through the opened first inlet to a first selected position inside the first gas replacement chamber, wherein the carrier is loaded with an operation object;
closing the first inlet, replacing the atmosphere in the first gas replacement chamber, then opening the first outlet, and transferring the carrier through the first outlet to a second selected position in the tunnel of the kiln body;
replacing the atmosphere in the second gas replacement chamber, when the second inlet and the second outlet are in a closed state, and then transferring the carrier through the opened second inlet to a third selected position of the second gas replacement chamber; and
closing the second inlet, and transferring the carrier through the opened second outlet to outside of the tunnel kiln.

Brief Description of Drawings

In order to more clearly describe the technical solutions of the embodiments of the present disclosure, the drawings required to be used in the embodiments will be simply introduced below; and it shall be understood that the following drawings merely show certain embodiments of the present disclosure, and thus should not be deemed as limiting the scope thereof, and for a person ordinarily skilled in the art, further relevant drawings could be obtained according to these drawings without inventive efforts.

Fig. 1 is a structural schematic drawing showing a tunnel kiln according to an embodiment of the present disclosure in a sectional view;
Fig. 2 shows a structural schematic drawing of the kiln body in the tunnel kiln of Fig. 1;
Fig. 3 shows a structural schematic drawing of a first tow chain in a first driving mechanism of the tunnel kiln of Fig. 1;
Fig. 4 shows a structural schematic drawing of a first transfer mechanism of the kiln body in the tunnel kiln of Fig. 1;
Fig. 5 shows a structural schematic drawing of the gas pipeline layout in a second gas replacement chamber of Fig. 1;
Fig. 6 shows a schematic drawing of the arrangement positions of sealing strips of the gas replacement chamber in the tunnel kiln of Fig. 1;
Fig. 7A shows a structural schematic drawing of a track in the tunnel kiln of Fig. 1;
Fig. 7B shows a structural schematic drawing of a pit track in the tunnel kiln of Fig. 1;
Fig. 7C shows a structural schematic drawing of guide tracks and roller sets in the tunnel kiln of Fig. 1;
Fig. 7D shows a structural schematic drawing of a track and rollerballs in the tunnel kiln of Fig. 1; and
Fig. 7E shows a structural schematic drawing of guide tracks and pin rollers in the tunnel kiln of Fig. 1.

Reference signs: 1a-kiln vehicle; 1b-kiln vehicle; 1c-kiln vehicle; 1d-kiln vehicle; 2-saggar stack; 4-kiln body; 5-first front gate; 5a-first inlet; 6-first vacuumizing pump; 7-first rear gate; 7a-second inlet; 8-second vacuumizing pump; 9-second front gate; 9a-first outlet; 10-second rear gate; 10a-second outlet; 11-heater; 11a-insulation board; 12-first transfer mechanism; 12a-second transfer mechanism; 13-first tow chain; 14-hydraulic propeller; 15-track; 15a-guide track at the bottom of the kiln vehicle; 15b-guide track at the bottom of the kiln vehicle; 15c-guide track at the bottom of the kiln furnace; 15d-guide track at the bottom of the kiln vehicle; 15e-guide track at the bottom of the kiln furnace; 16-furnace top; 18-processing atmosphere; 20-first triple vacuum valve; 21-second triple vacuum valve; 22-second front tow chain; 23-second rear tow chain; 24-first gas replacement chamber; 25-second gas replacement chamber; 26-first housing; 27-second housing; 28-third housing; 29-ram; 30-vehicle wheel; 30a-rollerball; 30b-pin roller; 30c-axle; 31-roller set; 32-gas injection port; 42-U-shaped structural track; 52-damping mechanism; 109-sealing strip; 110-gas pipeline; 110a-injector; 171-furnace wall; and 172-furnace wall.

Detailed Description of Embodiments

In view of deficiencies of existing car convey tunnel kilns, a novel car convey tunnel kiln is proposed in the present disclosure by the inventors, so as to improve problems regarding poor gas tightness of existing car convey tunnel kilns. By utilizing the car convey tunnel kiln proposed in the present disclosure, thermal treatment or thermochemical treatment operations can be performed without interference caused by gas outside the kiln furnace, and high-quality and large-scale product processing can be realized, such that cathode materials for lithium-ion batteries can be efficiently produced with a high quality.
In an embodiment, as shown in Fig. 1, the tunnel kiln comprises a kiln body 4, two gas replacement chambers (respectively a first gas replacement chamber 24 and a second gas replacement chamber 25), and gates.

Kiln body 4

In the above, the kiln body 4 is the main operation location for the thermal treatment or the thermochemical treatment of materials, and provides a reaction zone. The kiln body 4 has a tunnel, configured to serve as operation space for the thermal treatment or the thermochemical treatment of materials. As shown in Fig. 2, generally, the kiln body 4 can be composed of a furnace top 16 and furnace walls (respectively a furnace wall 171 and a furnace wall 172). Moreover, based on requirements of processing or the like, after-mentioned different apparatuses, such as heating, gas injection, gas extraction, and temperature measuring apparatuses, may be selectively provided on the furnace top 16, the furnace wall 171, and the furnace wall 172.
The kiln body has an internally located tunnel, which does not extend to the outside of the kiln body. Normally, the tunnel of the kiln body 4 has a heating-up zone, a heat preservation zone, and a cooling zone from an inlet port to an outlet port, which are configured to perform different thermal treatments on objects to be processed. In addition, the kiln body 4 further has a kiln head and a kiln tail. Thus, materials to be calcined can enter the tunnel through the inlet port from the kiln head, and successively pass through the heating-up zone, the heat preservation zone, and the cooling zone (in an embodiment, durations for staying in respective zones can be controlled as required), and then leave the kiln tail through the outlet port.
In addition to the above structures, structural adjustment or modification may be adaptively made to the kiln body 4 aiming at different requirements on thermal treatment or thermochemical treatment (e.g., calcination, wherein specific calcination temperature, calcination atmosphere or the like may be required), so as to meet specific demands.
For example, as required for the calcination temperature, the kiln body 4 may be correspondingly provided with a heating device so as to provide high temperature conditions required for calcination. Therefore, in an embodiment, an electric heater 11 can be provided vertically (relative to the direction from the inlet port to the outlet port of the tunnel) near a side face of the kiln body 4 (of course, a mode of combustion heating with a heat radiant tube may also be adopted directly, and components such as a burner can be correspondingly arranged). The quantity of electric heaters 11 can be selectively set according to conditions, such as tunnel length, cross-section dimension or the like. Moreover, generally, they can be preferably arranged in the heating-up zone, the heat preservation zone, and an indirect cooling-down zone.
For example, as required for the calcination atmosphere, injection can be selectively performed on a side wall of the kiln body 4 through a gas injection port 32, so as to inject a required process gas of different types, concentrations or the like as the process required.
In addition, in order to more accurately and duly control the calcination temperature and the calcination atmosphere in the tunnel of the kiln body 4, one or more temperature sensors and gas sensors may further be provided in the kiln body 4, so as to monitor the temperature and the atmosphere of a tunnel section that is required to be monitored. Correspondingly, the heating device and a gas injection device may also be adaptively operated according to monitored data. For example, if the tunnel temperature is lower than a setup requirement, the heating power of the heating device is required to be increased, and if the concentration of the atmosphere in the tunnel is insufficient, the injection speed of the injection device or the like is required to be increased. It shall be clarified that it is required to make the tunnel be in a vacuum state or in an atmosphere of an inert gas, when the atmosphere required for calcination is e.g. a non-oxidizing atmosphere, and in this case, gas extraction can also be performed through the abovementioned injection port, so as to realize gas replacement or gas evacuation. Alternatively, the kiln body 4 is independently equipped with an injection port and a gas extraction port, such that the injection and the gas extraction can be independently and selectively performed as required.
In order to facilitate the transportation of operation objects in the tunnel of the kiln body 4, a track 15 (such as hot-rolled light rails or other profiles that can be configured to support the weight of the kiln vehicle) can be laid at the bottom of the tunnel. Both ends of the track 15 terminate at the inlet port and the outlet port of the kiln body 4, respectively. In other words, the track 15 does not extend to the outside of the kiln body 4. The track 15 can be used as the travelling track of the kiln vehicle.
The kiln vehicle therein serves as an apparatus for transporting operation objects in respective gas replacement chambers and in the tunnel of the kiln body 4. Therefore, in an embodiment, a kiln vehicle can be equipped in the tunnel kiln, so as to carry stacked saggars and hold calcined materials by utilizing the saggars.
The movement of the kiln vehicle can be realized in such a way that the vehicle wheels 30 at the lower part of the vehicle body roll on the track (the kiln body 4 and the two gas replacement chambers are all respectively independently arranged).
As shown in Fig. 7A, the vehicle wheels 30 therein can also be arranged at both sides of the kiln vehicle, and correspondingly, the tracks can also be arranged at both sides of the kiln vehicle; and in an embodiment, the vehicle wheels 30 of the kiln vehicle can be each embedded in a track 42 of a U-shaped structure. Alternatively, as shown in Fig. 7B, the track is set to be in a pit track structure, and the kiln vehicle moves along this pit track. For example, the track is erected in a pre-casted concrete pit, and then, the kiln body 4 is erected on the concrete surface and the kiln body 4 and the concrete surface are then sealed.
Alternatively, as shown in Fig. 7C, a pair of guide tracks 15a are arranged at the bottom of the kiln vehicle, while two columns of fixed roller sets 31 are mounted at the bottom of the kiln furnace, and the kiln vehicle is enabled to travel inside the kiln body through the movement of the guide tracks 15a on the roller sets 30.
Alternatively, as shown in Fig. 7D, a pair of guide tracks 15b are arranged at the bottom of the kiln vehicle, the pair of guide tracks 15b and a pair of guide tracks 15c mounted at the bottom of the kiln furnace all have a V-shaped or concave cross-section, and a rollerball 30a is arranged between two guide tracks. The kiln vehicle is enabled to travel in the kiln body through the movement of the guide tracks 15b on the rollerballs 30a.
Alternatively, as shown in Fig. 7E, a pair of guide tracks 15d is arranged at the bottom of the kiln vehicle, this pair of guide tracks 15d and a pair of guide tracks 15e mounted at the bottom of the kiln furnace all have a V-shaped or concave cross-section, and a pin roller 30b is arranged between two guide tracks, wherein there is an axle 30c penetrating through the pin roller 30b, which is fixed with the kiln vehicle through the axle 30c. The kiln vehicle is enabled to travel in the kiln body through the movement of the pin roller 30b on the guide track 15e.
Alternatively, it is also an option to replace the vehicle wheels 30 of the kiln vehicle with a precise sliding pair, which tightly abuts against support surfaces (which may be the surfaces of the tracks 15) through sliding surfaces to enable the kiln vehicle to move forward through sliding.
Alternatively, the kiln vehicle may be a rack without wheels or sliding pairs. Correspondingly, the movement of the kiln vehicle within the furnace is driven by a chain transmission mechanism, that is, the kiln vehicle is placed on the chain transmission mechanism and then dragged by the chain.

First gas replacement chamber 24

The first gas replacement chamber 24 may be a gas-tight structure formed by welding a steel structural frame and a prefabricated sheet metal component. In the above, the steel structural frame (which may be equipped with a reinforcing rib) is located at the outside, and the prefabricated (laser-cut and bent) sheet metal component is attached to the inside of the steel structural frame. In the above, the steel structural frame mainly functions for strengthening and supporting refractory materials within the furnace and for mounting various components, while preventing force deformation during transportation or stress deformation during use. Optionally, the first gas replacement chamber 24 can also have a metal cover plate (it may be a sheet metal part), which is fixed with the steel structure by welding, hereby forming a chamber structure having a first inlet 5a and a first outlet 9a.
The first gas replacement chamber 24 (or referred to as inlet gas replacement chamber) is in connection with the kiln head end of the kiln body 4. Since the first gas replacement chamber 24 has the first inlet 5a and the first outlet 9a, the first gas replacement chamber 24 is in connection with an end of the kiln body 4 via the first outlet 9a thereof. In an embodiment, the first outlet 9a of the first gas replacement chamber 24 is connected to the kiln head end of the kiln body through a gate (which can be selectively opened or closed as required). The gate can ensure the communication of gas between the first gas replacement chamber 24 and the kiln body 4 or the isolation thereof under different working conditions. In addition, a gate may also be arranged at the first inlet 5a of the first gas replacement chamber 24, so as to form an independent sealed chamber through the gates of the first inlet 5a and the first outlet 9a for facilitating performance of gas replacement. The gate therein is in connection with the metal cover plate of the first gas replacement chamber 24. In an embodiment, as a structure having the function of improving gas tightness, the first gas replacement chamber 24 is covered by a gas-tight housing, and gates are respectively arranged at both ends of the housing, so as to selectively close the first inlet 5a and the first outlet 9a of the first gas replacement chamber. Alternatively, in an embodiment, the gate of the first gas replacement chamber 24 being in connection with the metal cover plate and the gate of the gas-tight housing may also share the same gate, so as to selectively open or close the first inlet 5a and the first outlet 9a. Alternatively, optionally, no metal cover plate may be provided on the first gas replacement chamber 24, but the gas-tight housing serves as a member having a function similar to that of the metal cover plate, and then the gate is connected to the gas-tight housing.
Considering that a sufficient positive pressure in the kiln body 4 may need to be maintained, and it is required to perform gas replacement in the first gas replacement chamber 24 and vacuumizing operations may correspondingly need to be performed, circumstances of a relatively great pressure difference may occur. In order to ensure the sealing effect, the gates at both ends of the first gas replacement chamber 24 can be provided with clamping devices. Besides, respective sealing surfaces of the gates on both sides of the first gas replacement chamber 24 are all arranged on the outside of the cavities of the replacement chambers. In this way, after falling down, the gates are tightly locked by the clamping devices, and in this case, when vacuumizing the first gas replacement chamber 24, the gas tightness of the gates can further be ensured, as sealing strips 109 (referring to Fig. 6) on the vacuum suction gate would be tightly adsorbed on the sealing surface.
On the basis of ensuring the gas tightness, a different gas replacement mode may also be used for the first gas replacement chamber. For example, gas replacement may be performed for the first gas replacement chamber 24 through gas flow purging. Optionally, in order to accelerate the gas replacement rate and make the atmosphere in the replacement chamber reach or approach the atmosphere in the tunnel of the kiln body 4 as soon as possible, a vacuum system/a vacuum device can be selectively arranged to be connected with the first gas replacement chamber 24.
In addition, a first transfer mechanism 12 as shown in Fig. 4 and a first driving mechanism are present in the first gas replacement chamber 24. The first driving mechanism is configured to drive the kiln vehicle for transferring the kiln vehicle. In the above, the first transfer mechanism 12 is independent of the track 15 in the kiln body 4.
On the one hand, the track 15 is arranged in the kiln body 4 without extending out of the kiln body 4. On the other hand, there is a gate between the kiln body 4 and the first gas replacement chamber 24. Therefore, the first transfer mechanism 12 and the track 15 are disconnected rather than continuous. The first transfer mechanism 12 is independent of the tunnel of the kiln body 4 and can cooperate therewith (e.g., docked therewith or moved away therefrom) through movement.
The first transfer mechanism 12 can move in the first gas replacement chamber 24, so as to facilitate the entry of the kiln vehicle into the first gas replacement chamber 24 from the outside of the tunnel kiln, and also to facilitate subsequent entry into the tunnel of the kiln body 4. When the length of the first gas replacement chamber 24 (along the direction from the kiln head to the kiln tail of the kiln body 4, i.e., the direction of the kiln vehicle movement) is relatively great, the solution, in which the first transfer mechanism 12 can move, can significantly improve the material conveying efficiency in the tunnel kiln. In an embodiment of the present disclosure, the length of the first gas replacement chamber can be set to accommodate one kiln vehicle; optionally, the length thereof can also be increased so as to simultaneously accommodate multiple kiln vehicles.
Based on the foregoing, materials are transported through the kiln vehicle, thus, the first transfer mechanism 12 can be configured to cooperate with the kiln vehicle, such that the kiln vehicle can be fixed thereon or move thereon. In other words, the first transfer mechanism 12 can serve as a transport apparatus for the kiln vehicle. The kiln vehicle is transported from the first gas replacement chamber 24 to a portion where the first gas replacement chamber is connected with the kiln body 4, and the kiln vehicle can subsequently enter the tunnel of the kiln body 4 through a gate in an opened state.
Optionally, for a steadier movement of the kiln vehicle, the first transfer mechanism 12 can be docked with a kiln vehicle track outside the tunnel kiln with a very small gap, so as to more conveniently transfer a kiln vehicle outside the kiln to the first gas replacement chamber 24. Optionally, the first transfer mechanism 12 can also be docked with the track 15 in the kiln body 4 with a very small gap, so the kiln vehicle can also be transferred from the first gas replacement chamber 24 to the track 15 in the kiln body 4 more steadily and smoothly. In short, by controlling the movement of the first transfer mechanism 12 for being selectively docked with a track outside the kiln or the track 15 in the kiln body 4, the kiln vehicle is enabled to be efficiently and smoothly perform conveying between the outside of the kiln, the first gas replacement chamber, and the kiln body 4, avoiding that an interrupted track jams the vehicle wheels 30 of the kiln vehicle or causes bumping of the kiln vehicle, which is accordingly contributive to the improvement of the conveying efficiency, reduces the wobble of saggars loaded with materials, prevents material splash, and further avoids a saggar from tilting and bumping against the tunnel inner wall. The kiln vehicle is an apparatus capable of being loaded with operation objects, and is constructed to be able to move on respective apparatuses, which is contributive to the improvement of the flexibility and the convenience of operations. The kiln vehicle itself may have no power drive and move relying on an external drive, or may carry its own power device and can move on its own.
As a specific and optional mode, the first transfer mechanism 12 may be a pair of tracks, which are separated from the track 15 in the kiln body 4. The lower part of each track has a rack. The first transfer mechanism 12 therein may also be replaced by other structures other than the pinion and rack, such as a ball screw or other moving pairs.
The movement of the entire track rack assembly is driven by lower gears. Driven by the gears, the entire track can move back and forth in the first gas replacement chamber 24, so as to be docked with the track 15 in the kiln body 4 or with a track outside the kiln outside the first gas replacement chamber 24 (outside the first inlet 5a), wherein there is a very small gap between docked tracks, which would not affect the stable operation of the kiln vehicle when passing.
When the gate at the first inlet 5a of the first gas replacement chamber 24 or the gate at the first outlet 9a is opened (one of the both is opened, while the other is closed), the gear drives the first transfer mechanism 12 to be docked with a track outside the kiln outside the first gas replacement chamber 24 or with the track 15 in the tunnel inlet of the kiln body 4. At this moment, the kiln vehicle can steadily move onto the first transfer mechanism 12 in the first gas replacement chamber 24 from the track outside the kiln outside the kiln furnace, or steadily move onto the track 15 in the tunnel inlet of the kiln body 4 from the first transfer mechanism 12 in the first gas replacement chamber 24. After the kiln vehicle enters or leave the first gas replacement chamber 24, the first transfer mechanism 12 can be driven by the gear and controlled by a sensor to return to a designated position, and make room for the falling gas-tight gate of the first inlet 5a, thereby realizing gas tightness.
In order to improve the smoothness of the movement of the first transfer mechanism 12, it may be an option not to arrange on a drive gear a support structure for the rack of the first transfer mechanism 12, instead, it is supported by an additional sliding pair with a smooth surface. Through such a support structure, sufficient strength can be provided to carry and move the heavy kiln vehicle. This sliding support pair can be a V-shaped groove, a U-shaped groove or have any other form, and can be optionally mounted on a steel structure in connection with the kiln body 4. The steel structure can be formed by welding profiles, of which the strength is sufficient to bear the left-right-motions in the horizontal direction while supporting the gravity in the vertical direction.
The drive gear of the first moving mechanism may be supplied with a driving force by a motor mounted outside the first gas replacement chamber 24 and a drive shaft. The drive shaft and the casing of the first gas replacement chamber 24 are sealed relying on a sealing element to prevent gas outside the gas replacement chamber from entering the gas replacement chamber through the gap.
In an embodiment, the transfer mechanism may include a drive motor or a drive shaft. In the above, the drive shaft is provided with a drive gear. Optionally, the transfer mechanism further includes a moving pair support and a main bearing support. The moving pair support contains a rack located at the bottom (the rack configured to receive a force from the drive gear to be able to move towards left and right). The main bearing support is formed by welding reinforcing profiles, and provide at upper part with a guide track (configured to bear a kiln vehicle, having a material identical with that of the tracks in the tunnel or outside the tunnel kiln). A sliding pair is mounted at the lower part of the main bearing support. A part of the sliding pair is in connection with the reinforcing casing of the gas replacement chamber and configured to bear the weight of the kiln vehicle, while the other part of the sliding pair is in connection with the main bearing support.
Furthermore, in order to prevent the kiln vehicle from improperly tilting and wobbling during the movement of the first transfer mechanism 12 in the first gas replacement chamber 24, it may be an option to respectively mount a damping mechanism 52 on inner walls of the first gas replacement chamber 24 at two sides of the kiln vehicle. When the kiln vehicle enters the first transfer mechanism 12 in the first gas replacement chamber 24, a side face of the kiln vehicle may contact this damping mechanism 52 so as to press against the damping mechanism 52, such that the kiln vehicle is decelerated until it is stationary. The damping mechanism 52 may be a damping plate mounted on the inner wall.
Meanwhile, when the first transfer mechanism 12 moves, the kiln vehicle is in contact with this damping mechanism 52 all along, and the damping mechanism 52 will keep the kiln vehicle have a stable attitude relative to the first gas replacement chamber 24, till the kiln vehicle is moved out of the first gas replacement chamber 24 by the first driving mechanism. In addition to the function of deceleration, the damping mechanism 52 can also function for preventing the kiln vehicle from tipping or tilting, so as to ensure a steady movement of the kiln vehicle. The damping mechanism 52 can correct and control the attitude and the speed of the kiln vehicle, and improve the steadiness of the movement of the kiln vehicle.
The structure of the first transfer mechanism 12 is described in the above content, and the structure of the first driving mechanism cooperating with the first transfer mechanism 12 will be described below in detail.
In an embodiment, the first driving mechanism may be a hydraulic push rod or a propulsion mechanism of any other form. Optionally, the first driving mechanism can be implemented using a combination of a first tow chain 13 (equipped with a motor for driving the tow chain) and a hydraulic propeller 14 (equipped with a hydraulic station, a hydraulic oil cylinder, and a push head), as shown in Figs. 1 and 3. The first tow chain 13 is driven by a motor, the motor is in connection with the first tow chain 13 through a shaft, and the first tow chain 13 and a sprocket are mounted within a casing and are engaged with each other. When the motor drives the shaft, the sprocket will also bring the first tow chain 13 to move forward or backward. The head of the first tow chain 13 is equipped with a mobile hook head for hooking a protrusion block at the bottom of the kiln vehicle; during operation, the motor firstly rotates in one direction and drives the first tow chain 13 to move, wherein the hook head is engaged with the protrusion block at the bottom of the kiln vehicle; then the motor rotates reversely, and the tow chain drags the kiln vehicle onto the track 15 or a transfer mechanism. The first tow chain 13 may be a chain bent at 90° or 180°. Once the chain is laid flat or bent, it is fairly rigid and can bear or push heavy loads. In addition, the tow chain structure further has following advantages: since the mounting dimension of the tow chain only amounts to a half of the whole route, the area occupied thereby will be much smaller than a hydraulic push rod and a propulsion mechanism of any other form, which indicates suitability for mounting in small and narrow spaces. Moreover, the tow chain can work freely in an environment under a temperature not higher than 500°C without lubrication, so it has high environmental adaptability.
In addition to the above-mentioned structures that could be equipped, the first gas replacement chamber 24 can also be provided with a preheating device based on the needs of use. This is based on the consideration that materials may release water vapor during the heating-up stage in the kiln body 4. Therefore, when the gate of the first gas replacement chamber 24 (located at the joint of the first gas replacement chamber 24 and the kiln body 4) is opened, the hot gas in the kiln body 4 encounters cold gas in the first gas replacement chamber 24, which causes condensation of the water vapor. The condensed water vapor will be deposited on the inner surface of the first gas replacement chamber 24, so that it is easy to drop into the topmost saggar of the stack on the kiln vehicle and enter the material. Alternatively, the water vapor condenses on the surface of the first driving mechanism, resulting in accelerated corrosion of metal components. Therefore, through the preheating device, the condensation of the water vapor can be prevented, and simultaneously the saggars and the materials can be heated in advance, hereby functioning for preheating.
As an optional specific implementation mode, the preheating device is constructed as an insulation plate 11a having a heating function and mounted in the cavity of the first gas replacement chamber 24. The temperature in the first gas replacement chamber 24 can be increased to e.g. about 90°C by utilizing the insulation plate 11a, and simultaneously, the temperature of the outer wallboard of the first gas replacement chamber 24 is kept at room temperature to avoid thermal damage to other components. In the above, the insulation plate 11a can be selected from commercially available products, and the heating function can be achieved by pre-burying heating tape(s) in the insulation plate 11a.

Second gas replacement chamber 25

The second gas replacement chamber 25 (or referred to as outlet gas replacement chamber) is connected to the kiln tail end of the kiln body 4. In other words, the first gas replacement chamber and the second gas replacement chamber are respectively located at two ends of the kiln body.
Specifically, the second gas replacement chamber 25 in the embodiment has a second inlet 7a and a second outlet 10a. Therefore, the second gas replacement chamber 25 is in connection with the kiln end of the kiln body 4 via the second inlet 7a. Moreover, as required by gas-tight connection and gas communication, a gate is provided between the second gas replacement chamber 25 and the kiln body 4. Meanwhile, the second outlet 10a of the second gas replacement chamber 25 is also correspondingly provided with a gate, so as to form an independent sealed chamber through the gates of the second inlet 7a and the second outlet 10a for facilitating performance of gas replacement. In an embodiment, the second gas replacement chamber 25 is covered by a gas-tight housing, and two ends of the housing are each provide with a gate, so as to be able to selectively close the second inlet 7a and the second outlet 10a of the second gas replacement chamber 25.
The two gas replacement chambers 24, 25 can facilitate the conveying of calcined materials into the kiln body 4, so as to avoid introduction of gas from outside of the tunnel kiln during the conveying of materials. Through settings about the structures of the gas replacement chambers 24, 25, tracks in the gas replacement chambers 24, 25 and in the kiln body 4 are enabled to be independent of each other, so as to conveniently provide gas-tight gates and ensure smooth and steady transfer of materials between the gas replacement chambers 24, 25 and the kiln body 4, and simultaneously further ensuring the gas tightness and avoiding introduction of gas from outside of the tunnel kiln, so as to allow continuous efficient production in the tunnel kiln.
In terms of dimensions, the second gas replacement chamber 25 and a second transfer mechanism 12a therein and a second driving mechanism configured to drive the kiln vehicle may be the same as or different from the first gas replacement chamber 24, or may be properly modified. In order to avoid repetitive description, it will not be described in detail in the present disclosure, and reference can be made to the preceding relevant content relating to the first gas replacement chamber 24.
In particular, in order to simplify the structure, the second driving mechanism in the second gas replacement chamber 25 may be improved. For example, the second driving mechanism may be composed of two tow chains (respectively a second front tow chain 22 and a second rear tow chain 23) mounted in opposite directions.
Based on the second driving mechanism of this structure, the kiln vehicle can be conveyed in the following manner.
In the present disclosure, the kiln vehicle can be conveyed by way of jack-in. For example, after entering the first gas replacement chamber 24 from the outside of the kiln, the kiln vehicle is conveyed into the kiln body 4 through the cooperation between the first transfer mechanism 12 and the first driving mechanism. Subsequent kiln vehicles outside the tunnel kiln can also be conveyed in this way, such that following kiln vehicles will push leading kiln vehicles and make them move on the track of the tunnel of the kiln body 4. In other words, to a certain extent, the forward (in the direction from the kiln head to the kiln tail) movement of kiln vehicles inside the tunnel kiln can be realized by jacking-in/pushing each other through continuous entry of kiln vehicles inside the first gas replacement chamber 24. If the kiln vehicles are continued to be pushed to approach the second gas replacement chamber, transfer operations can be performed through the second transfer mechanism 12a and the above-mentioned second driving mechanism having two opposite tow chains cooperating with each other.
Furthermore, in an embodiment, an apparatus corresponding to the preheating device arranged in the first gas replacement chamber 24 may be a cooling device arranged in the second gas replacement chamber 25. In other words, an operation object is preheated through the first gas replacement chamber 24 before entering the kiln body 4; and the operation object is cooled through the second gas replacement chamber 25 after leaving the kiln body 4 and before entering the outside (or subsequent treatment steps such as crushing).
The reason for arranging the cooling device lies in that:
Raw materials are calcined in the kiln body 4, and thus have a relatively high temperature. In this case, taking them directly to the outside may cause the problem of sudden drop in temperature. On this basis, before being moved out of the tunnel kiln, the materials are relatively more thoroughly cooled through the second gas replacement chamber 25, so as to cool calcined materials that are taken out of the kiln body and still have waste heat, which is accordingly contributive to reduction of thermal damages to apparatuses of subsequent treatment procedures.
Meanwhile, subsequent treatment of discharged materials can be carried out faster by cooling (additional cooling in other apparatuses is unnecessary, which often causes other problems, such as damages to the apparatuses, trouble in loading, etc.), hereby ensuring production efficiency. Preferably, as an improved use of the cooling device, it can be selectively constructed (in terms of position, quantity, and attitude or the like), such that temperature decrease of gradient descent can be realized for the kiln vehicle in the second gas replacement chamber 25.
In an embodiment, the cooling device may consist of a gas pipeline 110 as shown in Fig. 5 and an injector 110a (not shown). The gas pipeline 110 is inserted into the second gas replacement chamber 25, and the inserted portion is provided with gas holes facing the kiln vehicle therein, so as to be configured to spray cooling gas onto saggars for accelerating material cooling. The injector 110a can inject cooling gas into the second gas replacement chamber 25 through the gas pipeline 110, so as to cool the kiln vehicle and calcined materials therein. The cooling gas therein may be a process gas at room temperature (such as dry air, oxygen gas, nitrogen gas or the like).

Gate

In an embodiment of the present disclosure, gates are respectively arranged in four regions, i.e., the first inlet 5a of the first gas replacement chamber 24, the joint of the first outlet 9a and the kiln body 4, the joint of the second inlet 7a of the second gas replacement chamber 25 and the kiln body 4, and the second outlet 10a.
For facilitating the description and the understanding of the solution, terms such as first front gate 5, first rear gate 7, second front gate 9, and second rear gate 10 are used in the present disclosure for distinction.
In the above, the first front gate 5 can be in cooperative connection with the gas-tight housing surrounding the first gas replacement chamber 24. The second rear gate 10 can also be in cooperative connection with the gas-tight housing surrounding the second gas replacement chamber 25. The first rear gate 7 can be in connection with the gas-tight housing surrounding the first gas replacement chamber 24 and the gas-tight housing surrounding the kiln body 4. The second front gate 9 can be in connection with the gas-tight housing surrounding the kiln body 4 and the gas-tight housing surrounding the second gas replacement chamber 25.
In an embodiment, the first front gate 5 and the second rear gate 10 can be selectively arranged on inner surfaces of the gas replacement chambers, such that two gas-tight gates will compress a sealing device, when the two gas replacement chambers are vacuumized, so as to enhance the gas tightness of the gas replacement chambers.
As for the specific structure of the gate, a commercially available product can be used, so no detailed description will be made in the present disclosure. Furthermore, the structures of the gates at the above-mentioned positions may be identical or be different from each other, and no particular definition is made here in the present disclosure.

Gas-tight housing

Based on requirements of gas tightness, gas-tight protection is realized for the two gas replacement chambers and the kiln body 4 in an embodiment, that is, a gas-tight housing is provided, such that it wraps the kiln body 4, the first gas replacement chamber 24, and the second gas replacement chamber 25.
The gas-tight housing can be made of a steel structure, for example, is formed by welding a steel structural frame and a prefabricated sheet metal component. The steel structural frame and reinforcing rib(s) are located outside a sheet metal casing. After the prefabricated sheet metal component is attached to the accurate position of the steel structural frame, the sheet metal component and the steel structure frame are welded together. Full-length welding is realized inside and outside the welding seams produced by splicing sheet metal parts themselves, and dye penetrant inspection is utilized to confirm whether there is any welding pore or weld defect in the welding seams, so as to ensure that the furnace atmosphere does not leak. Such a structure is also suitable for the fabrication of sealed casings for the first gas replacement chamber 24 and the second gas replacement chamber 25.
The gas-tight housing can be a continuous structure, so as to wrap the kiln body 4, the first gas replacement chamber 24, and the second gas replacement chamber 25 together in the interior thereof. The gas-tight housing can serve as a supplementary member to the sealing function (relative to the gas replacement chamber constructed from sheet metal parts). Both ends of the gas-tight housing are respectively provided and connected with gates.
Alternatively, the gas-tight housing can selectively be configured as a split structure, thus, the gas-tight housing can respectively independently wrap the kiln body 4, the first gas replacement chamber 24, and the second gas replacement chamber 25. For distinction, the housing corresponding to the first gas replacement chamber 24 is referred to as first housing 26, the housing corresponding to the kiln body 4 is referred to as third housing 28, and the housing corresponding to the second gas replacement chamber 25 is referred to as second housing 27.
The gas-tight housing is configured as a split structure, sufficient operation space can be preserved for gates between the first gas replacement chamber 24 and the kiln body 4 and between the second gas replacement chamber 25 and the kiln body 4, so that the structural complexity and the mounting and operating difficulties of gates required by the parts can be accordingly lowered, while it is also possible to bring design advantages to the dimension of the gas-tight housing to a certain extent.
In an embodiment, the gas-tight housing can be divided into several segments for fabrication and processing. Each segment has a length of several meters. Each segment is in a box structure. The entire gas-tight housing can be formed by splicing multiple boxes consecutively. The splicing between segments is realized through front and rear flanges, and a gasket is mounted between the flanges.
Furthermore, as for practical apparatus fabrication and use process, before coating and using the gas-tight housing, the two gas replacement chambers, and the kiln body 4, all pores are sealed off, then the overall pressure test is carried out, and it can be used after the test fulfills gas-tight operating requirements.
In summary, relatively good gas tightness can be realized in the tunnel kiln proposed in the embodiments of the present disclosure, while the smooth proceeding of thermal treatment or thermochemical treatment operations can also be ensured, so as to realize highly efficient production of high quality. Optionally, the tunnel kiln can serve as a totally gas-tight car convey tunnel kiln, and can realize steady operation of the kiln vehicle (car) when entering the kiln body 4 from the kiln head and when being moved out of the kiln body 4 from the kiln tail, and special processing atmosphere for thermal treatment or thermochemical treatment can be adopted in the kiln body.
In order to enable a person skilled in the art to more easily understand and implement the solutions of the present disclosure, illustrative description about the use thereof will be made below, and explanations are made mainly about the moving path of a kiln vehicle configured to transport materials.
Fig. 1 shows states of a kiln vehicle in different positions during conveying. In the above, kiln vehicle 1a, kiln vehicle 1b, kiln vehicle 1c, and kiln vehicle 1d are respectively marked.

1. Entry of the kiln vehicle into the first gas replacement chamber 24

In a situation where the first rear gate 7 is closed, the first front gate 5 is opened. Then, the first transfer mechanism 12 in the first gas replacement chamber 24 is activated, such that it moves towards the direction of the first front gate 5 of the first gas replacement chamber 24 and is docked with a track (not shown) outside the first inlet 5a of the first gas replacement chamber 24. Subsequently, the first driving mechanism (mainly referring to the first tow chain) moves the kiln vehicle 1a outside the first inlet 5a onto the first transfer mechanism 12. Then, the first transfer mechanism 12 and the first tow chain in the first driving mechanism return to a designated position, and the first front gate 5 is then closed.

2. Replacement of gas of the first gas replacement chamber 24

After the kiln vehicle entered the first gas replacement chamber 24 and both the first front gate 5 and the first rear gate 7 are in a closed state, the gas in the first gas replacement chamber 24 is replaced by the atmosphere in the tunnel of the kiln body 4.

3. Entry of the kiln vehicle into the tunnel of the kiln body 4

The first front gate 5 is closed and the first rear gate 7 is opened, and the first transfer mechanism 12 is activated and moves towards the direction of the first rear gate 7, till it is docked with the track 15 at the kiln head of the kiln body 4. Then, the hydraulic propeller in the first driving mechanism propels the kiln vehicle onto the track 15 at the kiln head, which accordingly enters the kiln body 4 and accordingly comes into the state of the kiln vehicle 1b, and which can further be in the state of the kiln vehicle 1c through continuous feeding of the kiln vehicle. Meanwhile, the hydraulic propeller in the first driving mechanism and the first transfer mechanism 12 return to the designated position, and the first rear gate 7 is then closed.

4. Gas replacement of the second gas replacement chamber 25

When the second front gate 9 and the second rear gate 10 are in a closed state, the atmosphere in the second gas replacement chamber 25 is replaced by the atmosphere in the tunnel of the kiln body 4.

5. Entry of the kiln vehicle into the second gas replacement chamber 25

When the second rear gate 10 is in a closed state, the second front gate 9 is opened, and the second transfer mechanism 12a located in the second gas replacement chamber 25 is activated and moves towards the second front gate 9, till it is docked with the track 15 at the kiln tail of the kiln body 4. The second driving mechanism (the second front tow chain 22) in the second gas replacement chamber 25 moves the kiln vehicle on the track 15 at the kiln tail of the kiln body 4 onto the second transfer mechanism 12a, which accordingly enters the second gas replacement chamber 25 and is accordingly in the state of the kiln vehicle 1d. Meanwhile, the second transfer mechanism 12a and the second driving mechanism return to the designated position, and then the second front gate 9 is closed.

6. Exit of the kiln vehicle from the second gas replacement chamber 25

When the second front gate 9 is a closed state, the second rear gate 10 is opened, and the second transfer mechanism 12a in the second gas replacement chamber 25 is activated and moves towards the second rear gate 10, till it is docked with a track (not shown) outside the kiln outside the second gas replacement chamber 25. Then, the second driving mechanism (the second tow chain 23) moves the kiln vehicle from the second transfer mechanism 12a onto a track outside the kiln outside the second gas replacement chamber 25. Moreover, the second transfer mechanism and the second driving mechanism return to an initial position, and then the second rear gate 10 is closed.
Detailed steps of the kiln vehicle entering the tunnel kiln are explained below.
A kiln vehicle waits on a track outside the kiln outside the first gas replacement chamber 24. The track outside the kiln is provided for facilitating the conveying of kiln vehicles and matching the tunnel kiln. Alternatively, track outside the kiln may be not arranged according to different kiln vehicles.
The first front gate 5 of the first gas replacement chamber 24 is opened (while the first rear gate 7 remains closed), and the track of the first transfer mechanism 12 is docked when being driven by a gear with the track outside the kiln outside the first gas replacement chamber 24. The first tow chain 13 in the first gas replacement chamber 24 extends out and drags the kiln vehicle outside the kiln onto the track of the first gas replacement chamber 24, and the kiln vehicle stops at the designated position under the control of a sensor. If no track outside the kiln is provided, the kiln vehicle can be pushed into, or "travels" on its own into the first gas replacement chamber.
After that the position is determined by the sensor, the first front gate 5 is closed and locked. Then, a first triple vacuum valve 20 is opened, a first vacuumizing pump 6 evacuates the air in the first gas replacement chamber 24, while firmly sucking the first front gate 5 and the first rear gate 7. The first triple vacuum valve 20 then closes a valve being in connection with the vacuum pump, and opens the other end for introducing a gas identical with or similar to the furnace atmosphere or an unactive gas (such as nitrogen gas or the like), so as to perform inflation and purging on the replacement chamber.
After that the inflation and purging are completed, the first triple vacuum valve 20 performs opposite actions, and the vacuum pump is activated again for vacuumizing the replacement chamber again, and after gas replacement for several times, the atmosphere in the first gas replacement chamber 24 is identical with the atmosphere in the tunnel of the kiln body 4. The first rear gate 7 is opened (while the first front gate 5 remains closed). The first front gate 5 and the first rear gate 7 of the first gas replacement chamber 24 have interlock protection, so as to ensure that the inner gate and the outer gate will not be opened simultaneously.
After that the first rear gate 7 is opened, the track of the first transfer mechanism 12 is docked with the track 15 in the kiln head of the kiln body 4 when being driven by a gear. The first tow chain 13 pushes the kiln vehicle to a position approaching the kiln vehicle in the tunnel of the kiln body 4. At this moment, the ram 29 of the kiln vehicle is located above the hydraulic propeller 14, the first tow chain 13 is retracted, and the hydraulic propeller 14 is controlled by a servo to push/propel the kiln vehicle.
When there is no kiln vehicle in the kiln body for now, a kiln vehicle is pushed by the hydraulic propeller 14 and enters the kiln body. Meanwhile, the hydraulic propeller 14 stops and returns to the original position.
Alternatively, when there is already a kiln vehicle in the kiln body, the kiln vehicle is pushed by the hydraulic propeller 14 and enters the kiln body, and comes into contact with a kiln vehicle that is already present in the tunnel of the kiln body, and pushes this existing kiln vehicle, while the newly entered kiln vehicle reaches the position of the original kiln vehicle. Meanwhile, the hydraulic propeller 14 stops and returns to the original position.
In addition, the kiln vehicle moves to the position of the previous kiln vehicle. When the hydraulic propeller 14 begins to retreat, the first transfer mechanism 12 also retreats, and after the both are in place, the first rear gate 7 falls down and is locked. The first gas replacement chamber 24 enters an idle state and is ready for the entry of the next kiln vehicle.
Detailed steps for moving the kiln vehicle out of the tunnel kiln are illustrated by the following explanation.
When the second gas replacement chamber 25 has no kiln vehicle therein and is in an idle state, both the second front gate 9 and the second rear gate 10 are in the closed state. The atmosphere inside the second gas replacement chamber 25 has been replaced to be the same as the atmosphere inside the tunnel of the kiln body 4.
When the first front gate 5 of the first gas replacement chamber 24 is closed, the first rear gate 7 is opened, and the kiln vehicle is ready to enter the kiln head of the kiln body 4, the second front gate 9 of the second gas replacement chamber 25 is also opened at the same time (the second rear gate 10 remains closed).
Meanwhile, the track of the second transfer mechanism 12a in the second gas replacement chamber 25 is docked, when being driven by the gear, with the track 15 in the kiln tail of the kiln body 4. The second front tow chain 22 is activated and reaches a designated position to wait for the kiln vehicle to be in place. As the propeller of the first gas replacement chamber 24 pushes the kiln vehicle to the position of the previous kiln vehicle, the last kiln vehicle in the tunnel of the kiln body 4 is also be jacked-in by the rear kiln vehicle on the track and passes through the second front gate 9 of the second gas replacement chamber 25.
The second front tow chain 22 is activated and drags the kiln vehicle onto the track of the second transfer mechanism 12a of the second gas replacement chamber 25. After the sensor determines that the kiln vehicle stops at the designated position, the second transfer mechanism 12a and the second front tow chain 22 return to their original positions, and then the second front gate 9 is closed and locked.
After the second front gate 9 is closed, the kiln vehicle is in place. At this moment, the second rear gate 10 of the second gas replacement chamber 25 is opened, and the track of the second transfer mechanism 12a in the second gas replacement chamber 25 is docked with the track outside the second gas replacement chamber 25 when being driven by the gear. The second rear tow chain 23 drives the kiln vehicle from the track of the second transfer mechanism 12a onto a track outside the kiln outside the second gas replacement chamber 25. After the sensor determines that the kiln vehicle enters the designated position, the second transfer mechanism 12a and the second rear tow chain 23 return to their original positions, and then the second rear gate 10 is closed and locked.
Then, the second gas replacement chamber 25 is subjected to gas purging according to the same procedure as above, and the atmosphere in the second gas replacement chamber 25 is changed to be same as the atmosphere in the kiln body 4, so as to be prepared for the next same work procedure. For example, a second triple vacuum valve 21 is opened and evacuation is performed through a second vacuumizing pump 8.
The movement mode of the kiln vehicle has been explained above, and in a specific embodiment, reference can be made to following content for the operation and use mode of the tunnel kiln.
Firstly, the temperature of each section in the tunnel of the kiln body 4 is raised to a temperature predetermined by the process, and then the required process gas is introduced and the flow rate is adjusted.
Secondly, after adjusting the atmosphere and the temperature in the tunnel to the corresponding process requirements, kiln vehicles are transported as follows.
Kiln vehicles loaded with saggars (the saggars are loaded with operation objects) successively enter the first transfer mechanism 12 in the first gas replacement chamber of the tunnel kiln.
Then, the kiln vehicles are pushed to the track in the kiln body 4 by the first driving mechanism of the first gas replacement chamber. Kiln vehicles entering subsequently would tightly press against the preceding kiln vehicles on the track, and push the preceding kiln vehicles forward, till the entire tunnel is filled with kiln vehicles.
Then, the kiln vehicle at the kiln tail is dragged by the second driving mechanism in the second gas replacement chamber 25 onto the second transfer mechanism 12a in the second gas replacement chamber. It is then pushed out of the second gas replacement chamber and enters subsequent procedure treatment region.
Meanwhile, the kiln vehicle of the first gas replacement chamber enters the kiln head and pushes the kiln vehicle queue to move forward. Alternatively, the kiln vehicle at the kiln tail firstly enters the second gas replacement chamber 25, and the kiln vehicle at the kiln head then enters the first gas replacement chamber.
After the above steps, the material to be calcined will pass through different temperature zones in the tunnel to complete the calcination process. During the actual operation process, in order to improve the efficiency, two kiln vehicles at the kiln head and the kiln tail of the kiln body 4 enter and exit the tunnel of the kiln body at the same time. Moreover, after each kiln vehicle is jacked into the kiln body 4, it will stop for a while before the next kiln vehicle is jacked into the kiln furnace. The kiln vehicle queue in the tunnel kiln moves forward. The stop time is determined by the effective length of the kiln furnace, the setting of temperature zones, and process requirements.
Through the above-mentioned operations, a tunnel kiln can be utilized to perform thermal treatment of calcination on cathode materials of lithium-ion batteries, so as to meet requirements of introducing and maintaining a special atmosphere during calcination. Of course, the tunnel kiln can also be configured for production of other products, such as powder metallurgy, alloy processing, and sintering of ceramic materials.
As an example of applications, an embodiment provides a conveying method implemented by utilizing the above-mentioned tunnel kiln.
A calcination method comprises following steps.
Step S101: providing an operation environment inside the tunnel of the kiln body 4, when the first outlet 9a and the second inlet 7a are in a closed state.
When the first rear gate 7 and the second front gate 9 are closed, and the tunnel of the kiln body 4 is in a sealed state, an operation environment can be provided in the tunnel. The operation environment may vary according to different use manners of the tunnel kiln. For example, if the tunnel kiln is used as a calcination apparatus, the operation environment relates to e.g. calcination atmosphere/processing atmosphere 18 (as shown in Fig. 1), calcination temperature or the like.
Step S102: transferring a carrier outside the tunnel kiln through the opened first inlet 5a to the first transfer mechanism 12 and to a first selected position inside the first gas replacement chamber 24 through the first driving mechanism, wherein the carrier is loaded with an operation object.
In an embodiment, the kiln vehicle is loaded with a saggar stack 2, which is configured to hold an operation object, such as a battery material or inorganic material powers or articles.
The carrier may be a kiln vehicle or a transport device of any other type suitable for existing tunnel kilns. Optionally, the carrier may be implemented in various ways. Specific implementations for the carrier shall be adjusted according to the construction manner of the track for the "travel" of the carrier in the tunnel kiln, and no specific definition is made here in the present disclosure.
In order to facilitate the movement of the kiln vehicle, a track outside the kiln generally can be used. That is, a carrier outside the tunnel kiln can be conveyed into the first gas replacement chamber 24 through the track outside the kiln. Specifically, the first driving mechanism transfers the carrier outside the tunnel kiln to the first transfer mechanism 12 in the first gas replacement chamber 24. The first transfer mechanism 12 moves together with the carrier.
Step S103: closing the first inlet 5a, replacing the atmosphere in the first gas replacement chamber 24, then opening the first outlet 9a, and transferring the carrier through the first outlet 9a to a second selected position in the tunnel of the kiln body 4.
After the carrier moves into the first gas replacement chamber 24, it will subsequently be transferred into the tunnel of the kiln body 4. Thus, introduction of an undesired gas into the tunnel of the kiln body 4 through the first gas replacement chamber 24 can be avoided by replacing the gas in the first gas replacement chamber 24 by a desired atmosphere.
In an embodiment, the gates at both ends of the first gas replacement chamber 24 are closed, such that the first inlet 5a and the first outlet 9a are sealed up, making the first gas replacement chamber 24 sealed up. So far, in order to be same as the atmosphere in the tunnel of the kiln body 4, the atmosphere in the first gas replacement chamber 24 can be replaced just through a vacuum system or any other gas evacuation and injection apparatuses.
After the gas replacement in the first gas replacement chamber 24, the carrier is driven by the first driving mechanism and enters the tunnel of the kiln body 4. Moreover, the carrier in the tunnel can be pushed by a carrier that subsequently enters from the first gas replacement chamber 24 when being driven by the first driving mechanism and move in the tunnel. After the carrier enters the tunnel of the kiln body 4, the operation object (such as a battery material) in the carrier undergoes thermal treatment or thermochemical treatment in the tunnel, for example, is calcined or the like.
Step S104: replacing the atmosphere in the second gas replacement chamber 25, when the second inlet and the second outlet are in the closed state, and then transferring the carrier through the opened second inlet to a second transfer mechanism 12a which are then together transferred to a third selected position of the second gas replacement chamber 25.
After being treated in the tunnel, the operation object on the carrier is conveyed into the second gas replacement chamber 25. In order to avoid influences of the gas in the second gas replacement chamber 25 on the atmosphere in the tunnel, it is also required to replace the atmosphere in the second gas replacement chamber 25. In other words, gas is firstly replaced, before the carrier is transferred. That is to say, the second inlet and the second outlet are closed, and then the atmosphere in the second gas replacement chamber 25 is replaced through a gas evacuation and injection apparatus of the second gas replacement chamber 25, so as to be same as the atmosphere in the tunnel of the kiln body 4.
Step S105: closing the second inlet, and transferring the carrier through the opened second outlet to the outside of the tunnel kiln.
After the carrier enters the second gas replacement chamber 25, the second inlet is closed, so as to separate the second gas replacement chamber 25 from the tunnel of the kiln body 4. Therefore, the gas inside the second gas replacement chamber 25 would not interfere with the gas inside the tunnel of the kiln body 4. At this moment, the carrier can be transferred to the outside of the tunnel kiln. For example, the second transfer mechanism 12a is docked with the track outside the kiln outside the tunnel kiln, and then the second driving mechanism drives the carrier to the track outside the kiln. Subsequently, the second outlet can be closed.
If the entry of the carrier is subsequently still required, gas replacement can further be performed for the second gas replacement chamber 25, such that carriers that are subsequently pushed out of the tunnel of the kiln body 4 enter therein, so as to be prepared for the next same work procedure.
It should be pointed out that although respective steps are implemented during the above operations in a given sequence, it is not intended to define that each step therein can only be implemented in the above sequence. Partial steps may also be properly adjusted, so as to meet specific operation requirements.
For example, in the present disclosure, besides proceeding according to the above step sequence, the gas replacement in the first gas replacement chamber and the gas replacement in the second gas replacement chamber may also be performed simultaneously. For example, in the above step S103, gas in the second gas replacement chamber can also be replaced synchronously, while gas in the first gas replacement chamber is replaced. Alternatively, gas in the second gas replacement chamber 25 may optionally be replaced synchronously in the above step S101, when an operation environment is provided in the tunnel of the kiln body 4.
The above mentioned are merely preferable embodiments of the present disclosure, and is not intended to limit the present disclosure, and for a person skilled in the art, the present disclosure may be modified and changed in various ways. Any modifications, equivalent substitutions, and improvements made within the spirit and the principle of the present disclosure shall all be covered in the scope of protection of the present disclosure.

Industrial Applicability

Through the tunnel kiln and the conveying method according to the present disclosure, introduction of gas from outside of the tunnel kiln during the material conveying can be avoided, gas-tight gates can be conveniently arranged, and it can be ensured that materials are smoothly and steadily transferred between a gas replacement chamber and the kiln body, while the gas tightness can further be ensured and introduction of gas from outside of the tunnel kiln is avoided, so as to allow continuous efficient production of the tunnel kiln.

Claims

A tunnel kiln, characterized by comprising:
a kiln body, having an internally located tunnel which is provided with a track;

a first gas replacement chamber, having a first inlet and a first outlet, wherein the first gas replacement chamber is in connection with an end of the kiln body via the first outlet;

a second gas replacement chamber, having a second inlet and a second outlet, wherein the second gas replacement chamber is in connection with the other end of the kiln body via the second inlet;

gates configured to be selectively opened or closed, wherein the gates are respectively provided at the first inlet, the first outlet, the second inlet, and the second outlet; and

at least one kiln vehicle configured to be capable of moving through the first gas replacement chamber, the kiln body, and the second gas replacement chamber.
The tunnel kiln according to claim 1, wherein the tunnel kiln comprises a gas-tight housing, which is in connection with the gates and wraps the kiln body, the first gas replacement chamber, and the second gas replacement chamber.
The tunnel kiln according to claim 2, wherein the gas-tight housing is formed by welding a steel structural frame and a prefabricated sheet metal component.
The tunnel kiln according to any one of claims 1 to 3, wherein an independent first transfer mechanism configured for cooperating with the track and a first driving mechanism configured to drive the at least one kiln vehicle to move are provided in the first gas replacement chamber, and an independent second transfer mechanism configured for cooperating with the track and a second driving mechanism configured to drive the at least one kiln vehicle to move are provided in the second gas replacement chamber.
The tunnel kiln according to claim 4, wherein two ends of the track are able to be separably docked respectively with the first transfer mechanism and the second transfer mechanism.
The tunnel kiln according to claim 4 or 5, wherein the at least one kiln vehicle is configured to be able to selectively move in any one of the first transfer mechanism, the second transfer mechanism, and the track.
The tunnel kiln according to any one of claims 1 to 6, wherein the first gas replacement chamber and in the second gas replacement chamber are each provided therein with a damping mechanism configured for cooperating with the at least one kiln vehicle.
The tunnel kiln according to any one of claims 1 to 7, wherein the first gas replacement chamber is provided therein with a preheating device.
The tunnel kiln according to any one of claims 1 to 8, wherein the second gas replacement chamber is provided therein with a cooling device.
The tunnel kiln according to any one of claims 1 to 9, wherein a side wall of the kiln body is provided with a heater.
The tunnel kiln according to any one of claims 1 to 10, wherein a side wall of the kiln body is provided with a gas injection port.
The tunnel kiln according to any one of claims 1 to 11, wherein at least one temperature sensor is arranged in the kiln body.
The tunnel kiln according to any one of claims 1 to 12, wherein the first gas replacement chamber and the second gas replacement chamber are respectively independently provided with a vacuum device.
The tunnel kiln according to any one of claims 1 to 13, wherein a lower part of the at least one kiln vehicle is provided with vehicle wheels, and the at least one kiln vehicles is configured to move on the track through rolling of the vehicle wheels.
The tunnel kiln according to any one of claims 1 to 14, wherein the track is a U-shaped structural track or a pit track.
The tunnel kiln according to any one of claims 1 to 13, wherein a pair of guide tracks are arranged at a bottom of the at least one kiln vehicle, and two columns of fixed roller sets are mounted at a bottom of the kiln furnace, and the at least one kiln vehicle is configured to be able to travel forward inside the kiln body through movement of the guide tracks on the roller sets.
A conveying method, implementable by the tunnel kiln according to claim 1, characterized in that the method comprises:
providing an operation environment inside the tunnel of the kiln body, when the first outlet and the second inlet are in a closed state;

transferring a carrier outside the tunnel kiln through the opened first inlet to a first selected position inside the first gas replacement chamber, wherein the carrier is loaded with an operation object;

closing the first inlet, replacing an atmosphere in the first gas replacement chamber, then opening the first outlet, and transferring the carrier through the first outlet to a second selected position in the tunnel of the kiln body;

replacing an atmosphere in the second gas replacement chamber, when the second inlet and the second outlet are in a closed state, and then transferring the carrier through the opened second inlet to a third selected position of the second gas replacement chamber; and

closing the second inlet, and transferring the carrier through the opened second outlet to outside of the tunnel kiln.