CN213873744U - Tunnel kiln - Google Patents

Abstract

A tunnel kiln belongs to the field of lithium ion battery material processing. The tunnel kiln comprises a kiln body, a first gas displacement chamber, a second gas displacement chamber, a gate and an airtight shell. The first gas displacement chamber is connected with the second gas displacement chamber through the kiln body, and the inlets of the two gas displacement chambers and the joints of the two gas displacement chambers and the kiln body are provided with a gate. The kiln body, the gate and the two gas displacement chambers are connected in a matching way. The device can effectively control the interference of the outside air, thereby ensuring the normal and orderly operation of the heat treatment or the thermochemical treatment.

Description

Tunnel kiln

Technical Field

The application relates to the field of lithium ion battery material processing, in particular to a tunnel kiln.

Background

The positive active material of a lithium ion battery generally involves a heat treatment or thermochemical treatment, particularly a high temperature calcination step. Therefore, related manufacturing enterprises are always searching for new equipment and new methods for improving the calcination productivity of the cathode material so as to improve the production efficiency and reduce the processing cost of the cathode material.

Currently, the equipment for carrying out high-temperature calcination is generally a continuous tunnel kiln. The continuous tunnel kilns can be classified into push-plate type, roller-way type and wheel-rail type tunnel kilns. It is capable of continuous production for twenty-four hours, and therefore, it has a greater capacity than a batch kiln.

The push plate type tunnel kiln has a short effective heating length due to large resistance of a pushing mode, so that the capacity improvement potential is limited; the roller way type tunnel kiln has higher requirements on mechanical strength, high-temperature stability and the like of the roller rod, and the roller rod is easy to deform under high-temperature load, so that the potential of continuously increasing the productivity is limited. And the wheel-rail type tunnel kiln fundamentally avoids the defects of the wheel-rail type tunnel kiln and the wheel-rail type tunnel kiln, so that the wheel-rail type tunnel kiln has greater capacity improvement potential. However, for the positive electrode material requiring strict control of the high-temperature calcination atmosphere, the conventional wheel-rail tunnel kiln cannot be effectively applied, mainly because the gas tightness is poor, and the gas outside the wheel-rail tunnel kiln interferes with the calcination atmosphere inside the tunnel kiln.

SUMMERY OF THE UTILITY MODEL

In order to improve, even solve the problem that the outside gas of foretell wheel rail formula tunnel cave disturbs inside atmosphere, this application has proposed a tunnel cave.

The application is realized as follows:

in a first aspect, examples of the present application provide a tunnel kiln comprising a kiln car, a kiln body, a first gas displacement chamber, a second gas displacement chamber, a selectively openable and closable gate.

Wherein, the kiln body has the tunnel that is located inside, and the tunnel is provided with the track. The first gas displacement chamber has a first inlet and a first outlet. The first gas displacement chamber is connected to one end of the kiln body through a first outlet. The second gas displacement chamber has a second inlet and a second outlet. The second gas displacement chamber is connected with the other end of the kiln body through a second inlet. The first inlet, the first outlet, the second inlet and the second outlet are respectively provided with a gate. The kiln car is configured to be capable of passing through the first gas displacement chamber, the kiln gas, and the second gas displacement chamber.

The two gas replacement chambers can conveniently convey calcined materials to the kiln body, so that gas outside the tunnel kiln is prevented from being introduced in the process of conveying the materials. Through the design to the structure of gas replacement room for the track in gas replacement room and the kiln body can be independent, thereby can conveniently set up the gas tightness gate, and ensure that the material is unobstructed, smoothly shift between gas replacement room and the kiln body, can also ensure the gas tightness simultaneously and avoid introducing the outside gas of tunnel cave, thereby allow the continuous high-efficient production of tunnel cave.

According to some examples of the present application, the tunnel kiln includes a gas-tight enclosure, and the gas-tight enclosure encloses the kiln body, the first gas displacement chamber, and the second gas displacement chamber.

According to some examples of the present application, the first gas displacement chamber has a first transfer mechanism independent of and cooperating with the rail, a first drive mechanism for driving the kiln car in motion, and the second gas displacement chamber has a second transfer mechanism independent of and cooperating with the rail, a second drive mechanism for driving the kiln car in motion.

According to some examples of the present application, both ends of the kiln body tunnel can be detachably docked with the first transfer mechanism and the second transfer mechanism, respectively.

The transfer mechanism is butted with the track in the kiln body tunnel, so that the gap between the transfer mechanism and the track in the kiln body tunnel can be obviously reduced, and the smoothness of material conveying is improved.

According to some examples of the present application, the tunnel kiln includes a kiln car that is selectively movable in any one of the first transfer mechanism, the second transfer mechanism, and the kiln body track.

The kiln car can be used as equipment for loading operation objects. It is constructed to be movable in each apparatus, contributing to improved flexibility and convenience of operation. The kiln car can be driven by external power without power, or can move by itself with a power device.

According to some examples of the present application, a damping mechanism is disposed within each of the first and second gas displacement chambers for cooperating with a kiln car.

The damping mechanism can correct and control the posture and the speed of the kiln car, and the stability of the movement of the kiln car is improved.

According to some examples of the present application, the first gas displacement chamber has a preheating device therein.

According to some examples of the present application, the second gas displacement chamber has a cooling device therein.

According to some examples of the application, a sidewall of the kiln body has a heater.

According to some examples of the application, a side wall of the kiln body is provided with gas injection means.

According to some examples of the present application, the first gas displacement chamber and the second gas displacement chamber are each independently configured with a vacuum device.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are required to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained from the drawings without inventive effort.

FIG. 1 is a schematic cross-sectional view of a tunnel kiln in an example of the present application;

FIG. 2 shows a schematic structural view of a kiln body in the tunnel kiln of FIG. 1;

FIG. 3 shows a schematic structural view of a first drag chain in the first drive mechanism of the tunnel kiln of FIG. 1;

figure 4 shows a schematic structural view of a first transfer mechanism of the tunnel kiln of figure 1;

FIG. 5 shows a schematic diagram of the gas piping layout in the second gas displacement chamber of FIG. 1;

fig. 6 shows a schematic view of the arrangement position of the sealing strips for the gas replacement room in the tunnel kiln of fig. 1.

Icon: 1 a-a kiln car first position; 1 b-a second position of the kiln car; 1 c-kiln car third position; 1 d-kiln car fourth position; 171-furnace wall; 172-furnace wall; 2, stacking the saggars; 29-head collision; 5-a first front gate; 6-a first vacuum pump; 20-a first three-way vacuum valve; 11 a-a thermal insulation board; 26-a first housing; 27-a second housing; 28-a third housing; 13-a first tow chain; 12-a first transfer mechanism; 14-a hydraulic thruster; 24-a first gas displacement chamber; 7-a first rear gate; 4-a kiln body; 15-track; 18-process atmosphere; 16-a furnace roof; 11-a heater; 32-an air injection port; 9-a second front gate; 25-a second gas displacement chamber; 22-a second front tow chain; 23-a second rear tow chain; 10-a second rear gate; 21-a second three-way vacuum valve; 8-a second vacuum pump; 110-a gas pipeline; 109-sealing strip.

Detailed Description

Aiming at the defects of the existing wheel-rail type tunnel kiln, the inventor provides a novel wheel-rail type tunnel kiln in the application so as to improve the problem of poor air tightness of the existing wheel-rail type tunnel kiln. The wheel-rail type tunnel kiln provided by the application can be used for carrying out heat treatment or thermochemical treatment operation without being interfered by gas outside the kiln, so that high-quality and large-batch product processing is realized, and the wheel-rail type tunnel kiln can be used for efficient and high-quality production of the anode material of the lithium ion battery.

In an example, referring to fig. 1, a tunnel kiln comprises a kiln body 4, two gas displacement chambers (a first gas displacement chamber 24 and a second gas displacement chamber 25, respectively), a gate.

Kiln body 4

The kiln body 4 is a main operation part for heat treatment or thermochemical treatment of materials, and provides a reaction site. The kiln body 4 has a tunnel as a working space for heat treatment or thermochemical treatment of materials. In general, the kiln body 4 may be formed by a furnace roof 16 and furnace walls ( furnace walls 171 and 172, respectively), see fig. 2. And different equipment (such as heating, gas injection, gas extraction, temperature measurement equipment, etc.) may be optionally provided on the furnace top 16, the furnace walls, etc., as will be mentioned below, depending on the requirements of the process, etc.

The kiln body has a tunnel located within it, and therefore, the tunnel does not extend outside the kiln body. The tunnel of the kiln body 4 usually has a heating zone, a holding zone and a cooling zone from the inlet opening to the outlet opening for the different heat treatments of the object to be processed. Meanwhile, the kiln body 4 is also provided with a kiln head and a kiln tail. Therefore, the material to be calcined can enter the tunnel from the kiln head through the inlet, sequentially pass through the heating zone, the holding zone and the cooling zone (in some examples, the residence time in each zone can be controlled according to requirements), and then leave the kiln tail through the outlet.

In addition to the above structure, the kiln body 4 can be adaptively adjusted or modified to meet specific requirements according to different requirements of thermal or thermochemical treatment (such as calcination, which may require specific calcination temperature, calcination atmosphere, etc.).

For example, the kiln body 4 may be provided with a heating device corresponding to the requirement of the calcination temperature to provide the high temperature condition required for calcination. Therefore, in some examples, the electric heater 11 may be disposed vertically (with respect to the direction from the inlet to the outlet of the tunnel) near the side surface of the kiln body 4 (of course, a combustion heating method with a heat radiation pipe may be directly used, and accordingly, a burner or the like may be provided). The number of the electric heaters 11 may be selectively designed according to the conditions of the tunnel length, the sectional size, etc. And, in general, it may be preferable to set the temperature rise region, the temperature hold region, and the indirect cooling region.

For example, for the requirement of the calcining atmosphere, the side wall of the kiln body 4 can be selectively filled with gas through the gas injection ports 32, so as to inject process gases with different types, concentrations and the like according to the requirements of the process.

In addition, in order to more accurately and timely control the calcining temperature and the calcining atmosphere in the tunnel of the kiln body 4, a temperature sensor and a gas sensor can be arranged on the kiln body 4 so as to monitor the temperature and the atmosphere of the tunnel section to be monitored. Accordingly, the heating device and the gas injection device can also be operated adaptively according to the monitored data. For example, if the tunnel temperature is lower than the design requirement, the heating temperature of the heating device needs to be increased. For example, the concentration of the atmosphere in the tunnel is insufficient, and it is necessary to increase the injection means such as the injection speed and the like. When the atmosphere required for the calcination is, for example, a non-oxidizing atmosphere, it may be necessary to make the inside of the tunnel a vacuum or an inert atmosphere, and the gas may be evacuated through the injection port to replace the gas or evacuate the gas. Alternatively, the injection port and the exhaust port are provided independently in the kiln body 4 so that the injection and the exhaust can be selectively performed independently as needed.

In order to facilitate the transportation of the work object in the tunnel of the kiln body 4, rails 15 (such as hot rolled light rails or other profiles that can be used to support the weight of the kiln car) can be laid on the bottom of the tunnel. The track 15 terminates at its two ends in an inlet and an outlet, respectively, of the kiln body 4. In other words, the rails 15 do not extend outside the kiln body 4. The rail 15 can be used as a running rail of the kiln car.

The kiln car is used as equipment for transporting operation objects in tunnels of each gas displacement chamber and the kiln body 4. Thus, in some examples, the tunnel kiln may be configured with kiln cars to carry stacked saggars and utilize the saggar storage to hold the calcination material.

The motion mode of the kiln car can be realized by rolling wheels positioned at the lower part of the car body on a track (the kiln body 4 and the two gas replacement chambers are respectively and independently arranged).

The wheels can be designed on two sides of the kiln car, and correspondingly, the rails can be arranged on two sides of the kiln car; and in this example, the wheels of the kiln car may be embedded in the rails of the U-shaped structure. Or the track is designed into a pit track structure, and the kiln car moves on the pit track. For example, the track is erected in a pre-cast concrete pit, the kiln body 4 is erected on the concrete surface, and then the kiln body 4 is sealed with the concrete surface.

Or a pair of guide rails is arranged at the bottom of the kiln car, two fixed roller groups are arranged at the bottom of the kiln, and the kiln car moves in the tunnel kiln body by the movement of the guide rails on the roller groups.

Alternatively, the kiln car may be advanced by changing the wheels into precision sliding pairs and by pushing the sliding surfaces against the support surfaces (which may be the surfaces of the rails 15).

Alternatively, the kiln car may be a rack, which has no wheels or sliding pairs. Correspondingly, the kiln car moves in the furnace and is driven by a chain type transmission mechanism, namely, the kiln car is placed on the chain transmission mechanism and then is dragged by a chain.

First gas displacement chamber 24

The first gas displacement chamber 24 may be welded together using steel frame and sheet metal prefabricated components to form an airtight structure. The steel structure frame (which can be provided with reinforcing ribs) is positioned outside, and a sheet metal part formed by prefabricating (laser cutting and bending) is attached inside the steel structure frame. The steel structure frame mainly plays a role in strengthening and supporting refractory materials in the furnace and installing various components, and simultaneously prevents stress deformation in the transportation process or the use process. Further, the first gas displacement chamber 24 may also have a metal cover plate (which may be a sheet metal member) welded to a steel structure to form a chamber structure having a first inlet and a first outlet.

A first gas displacement chamber 24 (or inlet gas displacement chamber) is connected to the kiln head end of the kiln body 4. Since the first gas displacement chamber 24 has a first inlet and a first outlet, the first gas displacement chamber 24 is connected to one end of the kiln body 4 through its first outlet. In the illustrated example, the first outlet of the first gas displacement chamber 24 is connected to the head end of the kiln body by a gate (which can be selectively opened and closed as desired). The shutter ensures that the first gas displacement chamber 24 is in gas communication or isolated from the kiln body 4 in different operating states. In addition, the first inlet of the first gas replacement chamber 24 is also provided with a shutter so that a separate closed chamber is formed by the shutter of the first inlet and the first outlet for gas replacement. Wherein the shutter is connected to the metal cover plate of the first gas displacement chamber 24. In an example, as a function of improving the airtightness, the first gas replacement chamber 24 is enclosed by an airtight casing, and gates are provided at both ends of the casing, so that the first inlet and the first outlet of the first gas replacement chamber can be selectively closed. Alternatively, in other examples, the metal cover and the airtight enclosure of the first gas displacement chamber 24 may share a gate to selectively open or close the first inlet and the first outlet. Alternatively, in other examples, the first gas replacement chamber 24 may be provided without a metal cover plate, and a gas-tight casing may be used as a member having a function similar to that of the metal cover plate, and then the gate may be connected to the outer gas-tight casing.

It is contemplated that a sufficient positive pressure may need to be maintained within the kiln body 4 and gas displacement within the first gas displacement chamber 24 may need to be performed-a vacuum pumping operation may accordingly need to be performed-and, therefore, a pressure differential may be large. In order to ensure the sealing action, the shutters at both ends of the first gas displacement chamber 24 can be designed as clamping devices. In addition, the dual door sealing surfaces of the first gas displacement chamber 24 are designed to be outside of the displacement chamber cavity. Thus, the gate is locked after falling and by the locking mechanism. In this way, when the vacuum is drawn in the first gas replacement chamber 24, the sealing strip 109 (see fig. 6) of the vacuum suction door is tightly attached to the sealing surface, thereby further ensuring the airtightness of the gate.

The gas replacement of the first gas replacement chamber may also be designed differently, in addition to ensuring gas tightness. For example, the first gas displacement chamber 24 may be purged with a gas stream. Further, in order to accelerate the rate of gas displacement and to bring the atmosphere in the displacement chamber as quickly as possible to or close to the atmosphere in the tunnel of the kiln body 4, a vacuum system/vacuum device may optionally be designed in connection with the first gas displacement chamber 24.

The first gas replacement chamber 24 includes the first transfer mechanism 12 and the first drive mechanism shown in fig. 4. The first driving mechanism is used for driving the kiln car so as to transfer the kiln car. Wherein the first transfer means 12 are independent of the rails 15 inside the kiln body 4.

On the one hand, the rails 15 are arranged in the kiln body 4 and do not extend out of the kiln body 4. Another aspect is that there is a gate between the kiln body 4 and the first gas displacement chamber 24. Thus, there is a break, not a discontinuity, between the first transfer mechanism 12 and the track 15. The first transfer means 12 are independent of the tunnel of the kiln body 4 and can cooperate with it by moving, for example, into abutment or away from it.

The first transfer mechanism 12 is movable within the first gas displacement chamber 24 to facilitate the entry of the kiln car from outside the tunnel kiln into the first gas displacement chamber 24 and subsequently into the tunnel of the kiln body 4. When the length of the first gas displacement chamber 24 (along the direction from the front to the rear of the kiln body 4) is large, the movable scheme of the first transfer mechanism 12 can obviously improve the material conveying efficiency in the tunnel kiln. In the present example, the first gas displacement chamber may be of a length designed to accommodate one kiln car; in other examples, the length may be increased to accommodate multiple kiln cars simultaneously.

Based on the foregoing, material is transported through the kiln car, and thus, the first transfer mechanism 12 may be configured to cooperate with the kiln car such that the kiln car may be fixed or movable thereon. In other words, the first transfer mechanism 12 may serve as a transport device for the kiln car. The kiln car is transported from the first gas displacement chamber 24 to its connection with the kiln body 4, where it can then enter the tunnel of the kiln body 4 through the sluice gate in the open state.

Further, in order to make the movement of the kiln cars more stable, the first transfer mechanism 12 may be butted against the kiln car rails outside the tunnel kiln with a small gap, thereby more conveniently transferring the kiln cars outside the kiln to the first gas replacement chamber 24. Further, the first transfer mechanism 12 can also be abutted with the rails 15 in the kiln body 4 with a small clearance, and therefore, the kiln car can be transferred from the first gas replacement chamber 24 to the rails 15 in the kiln body 4 more smoothly. In short, through the controlled motion of first transfer mechanism 12 and selectivity and kiln outer track to and 15 docks of track in the kiln body 4, make the kiln car can be outside the kiln, high-efficient, smoothly transport between first gas replacement room and the kiln body 4, the track of avoiding breaking blocks the kiln car wheel or causes jolting of kiln car, thereby help improving conveying efficiency, reduce the rocking of the casket-like bowl of loading the material, prevent that the material from splashing, can also avoid the casket-like bowl slope to collide with the tunnel inner wall.

As a specific and alternative realization, the first transfer means 12 can be a pair of rails, which are isolated from the rails 15 inside the kiln body 4. The lower part of each track is provided with a rack. The first transfer mechanism 12 may be replaced by other structures besides a rack and pinion, such as a ball screw or other moving pair.

The movement of the whole track rack assembly is driven by the lower gear. Through the drive of gear, whole track can move back and forth in first gas replacement room 24, with the track 15 in the kiln body 4 or the kiln outer rail butt joint outside first gas replacement room 24 (outside the first entry), the gap between the track after the butt joint is very little, does not influence the steady operation when the kiln car passes through.

When the gate of the first inlet or the gate of the first outlet of the first gas displacement chamber 24 is open (one of them is open and the other is closed), the gear drives the first transfer mechanism 12 into abutment with the out-of-kiln track outside the first gas displacement chamber 24 or into abutment with the track 15 inside the tunnel inlet of the kiln body 4. At this time, the kiln car can smoothly enter the first transfer mechanism in the first gas replacement chamber 24 from the track outside the kiln or smoothly enter the tunnel entrance inner track 15 of the kiln body 4 from the first transfer mechanism in the first gas replacement chamber 24. After the kiln car enters or leaves the first gas displacement chamber 24, the first transfer mechanism 12 can be controlled by a gear drive and a sensor to return to a designated position, and the space required for the airtight gate of the first inlet to fall is made available, so that airtightness is realized.

In order to improve the movement fluency of the first transfer mechanism 12, the support structure of the rack of the first transfer mechanism 12 may be selected not to be arranged on the driving gear, but to be provided with a sliding pair support with a smooth surface. Through the design of the supporting structure, enough strength can be provided for bearing heavy kiln cars and moving the kiln cars. The sliding support pair can be a V-shaped groove, a U-shaped groove or any other form, and can be selectively arranged on a steel structure connected with the kiln body 4. The steel structure may be welded from profiles, which are strong enough to support the gravity in the vertical direction while bearing the gravity in the horizontal direction and then move left and right.

The drive gear of the first movement mechanism may be powered by a motor and drive shaft mounted outside the first gas displacement chamber 24. The drive shaft is sealed to the housing of the first gas displacement chamber 24 by a seal that prevents gas from outside the gas displacement chamber from entering the gas displacement chamber through the gap.

In some examples, the transfer mechanism may include a drive motor, a drive shaft. Wherein the drive shaft is provided with a drive gear. Further, the transfer mechanism also comprises a movable auxiliary bracket and a main bearing bracket. The moving pair bracket comprises a rack at the bottom (for receiving power from the driving gear and moving left and right). The main bearing bracket is formed by welding reinforced section bars, and a guide rail (used for bearing a kiln car, and the material of the main bearing bracket is consistent with that of a track in a tunnel or outside the tunnel kiln) is arranged at the upper part of the main bearing bracket. The lower part of the main bearing bracket is provided with a sliding pair. One part of the sliding pair is connected with the reinforced shell of the gas replacement chamber for bearing the weight of the kiln car, and the other part of the sliding pair is connected with the main bearing bracket.

In addition, in order to prevent the kiln car from being improperly inclined and shaken when the first transfer mechanism 12 moves in the first gas replacement chamber 24, a damping mechanism may be selectively installed on each of the inner walls of the first gas replacement chamber 24 on both sides of the kiln car. As the kiln car enters the first transfer mechanism in the first gas displacement chamber 24, the side of the kiln car contacts the damping mechanism, thereby compressing the damping mechanism and slowing the kiln car to a standstill. The damping mechanism may be a damping plate mounted to the inner wall.

Meanwhile, when the first transfer mechanism 12 moves, the kiln car is always in contact with the damping mechanism, and the damping mechanism can keep the kiln car in a stable posture relative to the first gas replacement chamber 24 until the kiln car is moved out of the first gas replacement chamber 24 by the first driving mechanism. The damping mechanism can play a role in speed reduction and can also play a role in preventing the kiln car from toppling and inclining so as to ensure that the kiln car moves stably.

The above description explains the structure of the first transfer mechanism, and the structure of the first drive mechanism cooperating with the first transfer mechanism will be described in detail below.

In some examples, the first drive mechanism may be a hydraulic ram or other form of propulsion mechanism. In other examples, the first drive mechanism may be implemented using a first drag chain 13 (configured with a motor to drive the drag chain) and a hydraulic thruster 14 (configured with a hydraulic station, a hydraulic ram and a thrust head) in combination, see fig. 1 and 3. The first drag chain 13 may be a chain that can be bent at 90 ° or 180 °. The chain, once laid flat or bent, is relatively rigid and can carry or lift heavy objects. In addition, the drag chain structure has some advantages as follows: because the installation size of tow chain is only half of full stroke, consequently, its area that occupies can be much less than hydraulic push rod and other forms advancing mechanism, is fit for installing in narrow and small space. And the drag chain can freely work in the environment of not higher than 500 ℃ without lubrication, thereby having higher environmental adaptability.

The first gas displacement chamber may be provided with a preheating device based on the use requirement, such as preheating, in addition to the above-described configuration. This is based on the consideration that: the material may release water vapor during the temperature rise phase in the kiln body 4. Thus, when the shutter of the first gas displacement chamber 24 (located at the junction of the first gas displacement chamber 24 and the kiln body 4) is opened, the hot gas in the kiln body 4 and the cold gas in the first gas displacement chamber 24 meet, causing condensation of the water vapor. This condensed water vapor will deposit on the interior surfaces of the first gas displacement chamber 24 and will tend to drip into the topmost sagger of the stack on the kiln car and into the material. Alternatively, moisture condensation on the surface of the first drive mechanism can lead to accelerated corrosion of the metal components. Therefore, can prevent through preheating device that steam from condensing, can also heat sagger and material in advance simultaneously, play the preheating function.

As an alternative specific implementation, the preheating device is configured as a heat-insulating plate 11a with a heating function installed inside the cavity of the first gas replacement chamber 24. The heat insulating plate 11a can increase the temperature in the first gas replacement chamber 24 to, for example, about 90 ℃, and the temperature of the outer wall plate of the first gas replacement chamber 24 can be maintained at room temperature, thereby avoiding thermal damage to other components. The heat preservation board 11a can be selected from commercially available products, and the heating function is realized by embedding the heating belt in the heat preservation board 11 a.

Second gas replacement chamber 25

The second gas displacement chamber 25 (or outlet gas displacement chamber) is connected to the kiln end of the kiln body 4. In other words, the first gas displacement chamber and the second gas displacement chamber are located at both ends of the kiln body, respectively.

Specifically, the second gas displacement chamber 25 in the example has a second inlet and a second outlet, and therefore, the second gas displacement chamber 25 is connected to the kiln tail of the kiln body 4 through the second inlet. Further, a shutter is disposed between the second gas replacement chamber 25 and the kiln body 4 for the purpose of gas-tight connection and gas communication. Meanwhile, the second outlet of the second gas replacement chamber 25 is also provided with a gate, so that an independent closed chamber is formed by the gates of the second inlet and the second outlet, so as to perform gas replacement. In an example, the second gas replacement chamber is enclosed by a gas-tight housing, and gates are provided at both ends of the housing so as to selectively close the second inlet and the second outlet of the second gas replacement chamber.

The second gas displacement chamber 25, and the second transfer mechanism and second drive mechanism therein for driving the kiln car, may be the same as or different in size from the first gas displacement chamber 24 or suitably modified. To avoid redundancy, details thereof are not provided herein, and reference is made to the related description of the first gas displacement chamber 24.

In particular, the second driving mechanism in the second gas replacement chamber 25 may be modified for the sake of simplification of the structure. For example, the second driving mechanism may be composed of two drag chains (the second front drag chain 22 and the second rear drag chain 23, respectively) installed in opposite directions.

Based on the second driving mechanism of the structure, the kiln car can be conveyed in the following way.

In the present application, the kiln car may be transported by jacking. For example, after entering the first gas replacement chamber 24 from outside the kiln, the kiln car is conveyed into the kiln body 4 by the first transfer mechanism 12 and the first driving mechanism in cooperation. The subsequent kiln cars outside the tunnel kiln can also be transported in this way, so that the following kiln car will push the preceding kiln car to move on the track of the tunnel of the kiln body 4. In other words, to the extent that the kiln cars within the tunnel kiln move forward (in the direction from the kiln head to the kiln tail), they may be pushed/propelled against each other by the constant entry of the kiln cars within the first gas displacement chamber 24. The transfer operation may be performed by a second drive mechanism coupled to the second transfer mechanism and the two opposing drag chains as the kiln car is further jacked into proximity with the second gas displacement chamber.

Further, a corresponding device to the arrangement of the preheating device in the first gas replacement chamber 24, in some examples, may be a cooling device in the second gas replacement chamber 25. In other words, the work object is preheated by the first gas replacement chamber 24 before entering the kiln body 4; after leaving the kiln body 4 and before entering the outside (or a subsequent process step such as pulverization), the work object is cooled in the second gas replacement chamber 25.

The reason for providing the cooling device is that:

the raw material is calcined in the kiln body 4 and thus has a relatively high temperature, and direct withdrawal to the outside may cause a problem of sudden temperature drop. On this basis, a relatively more thorough cooling is carried out by the second gas displacement chamber 25 before the material is removed from the tunnel kiln in order to reduce the calcined material coming out of the kiln body and also having residual heat, thereby contributing to a reduction in thermal damage to the equipment of the subsequent treatment process.

Meanwhile, the subsequent treatment of the discharged material can be carried out more quickly through cooling (additional cooling at other equipment is not needed, and other problems such as equipment damage, trouble in charging and the like are caused frequently), so that the production efficiency is ensured. Preferably, as an improved cooling means, it can be selectively (position, number and attitude, etc.) configured so that the kiln car can achieve a gradient decreasing temperature reduction in the second gas displacement chamber 25.

As an example, the cooling device may be composed of a gas pipe 110 and an injector (not shown) as shown in fig. 5. The gas pipe 110 is inserted into the second gas replacement chamber 25, and the insertion portion is provided with gas holes in a manner toward the kiln car therein for injecting cooling gas toward the sagger to accelerate the cooling of the material. The injector may inject cooling gas through the gas conduit 110 into the second gas displacement chamber 25 to cool the kiln car and the calcined material therein. The cooling gas may be a process gas (e.g., dry air, oxygen, or nitrogen, etc.) at room temperature.

Gate valve

In the example of the present application, gates are provided in four regions, respectively, a first inlet of the first gas replacement chamber 24, a junction of the first outlet and the kiln body 4, a second inlet of the second gas replacement chamber 25, a junction of the kiln body 4, and a second outlet.

For convenience of description and understanding of the scheme, a distinction is made in the present application between the first front gate 5, the first rear gate 7, the second front gate 9, and the second rear gate 10.

Wherein the first front gate 5 can be fittingly connected to a gas tight housing enclosing the first gas displacement chamber 24. The second rear gate 10 may also be coupled to a gas-tight enclosure enclosing the second gas displacement chamber 25. The first rear gate 7 may be connected to a gas-tight housing enclosing the first gas displacement chamber 24, a gas-tight housing enclosing the kiln body 4. The second front lock 9 can be connected to a gas-tight casing enclosing the kiln body 4 and a gas-tight casing enclosing the second gas displacement chamber 25.

In some examples, the first front gate 5 and the second rear gate 10 may be selectively disposed on the inner surface of the gas replacement chamber, so that when the two gas replacement chambers are vacuumized, the two airtight gates may press the sealing device, thereby enhancing the airtightness of the gas replacement chambers.

As for the specific structure of the gate, commercially available products can be used, and therefore, detailed description thereof will not be provided in the present application. The gates may have the same or different structures, and the present application is not particularly limited thereto.

Airtight housing

The two gas displacement chambers and the kiln body 4 are protected gas-tightly in the example on account of the requirements of the gas-tight design, i.e. by providing a gas-tight housing which encloses the kiln body 4, the first gas displacement chamber 24 and the second gas displacement chamber 25.

The gas-tight casing can be made of steel structure, for example, a steel structure frame and a sheet metal prefabricated part are welded. The steel structure frame and the reinforcing ribs are located outside the sheet metal shell. After the prefabricated sheet metal part is attached to the accurate position of the steel structure frame, the sheet metal part and the steel structure frame are welded together. The inside and outside of the welding seam spliced by the sheet metal part is fully welded, and whether the welding seam has any welding pores or welding defects is confirmed by dye penetrant inspection, so that the atmosphere in the furnace is ensured not to leak. Such a design is also suitable for making a sealed housing for the first gas displacement chamber 24 and the second gas displacement chamber 25.

The gas-tight enclosure may be a continuous structure so as to enclose the kiln body 4, the first gas displacement chamber 24 and the second gas displacement chamber 25 together inside. The gas-tight housing may serve as a supplementary component to the sealing function (in contrast to gas displacement chambers that have been constructed from sheet metal parts). Two ends of the airtight shell are respectively connected with a gate.

Alternatively, the airtight housing may be designed to be a separate body, and thus, the airtight housing may independently enclose the kiln body 4, the first gas replacement chamber 24, and the second gas replacement chamber 25, respectively. For the sake of distinction, the housing corresponding to the first gas displacement chamber 24 is a first housing 26, the housing corresponding to the kiln body 4 is a third housing 28, and the housing corresponding to the second gas displacement chamber 25 is a second housing 27.

The design of gas tightness shell is split type structure, can reserve abundant operating space for the first gas replacement room 24 and the kiln body 4 to and the gate between second gas replacement room 25 and the kiln body 4 to can reduce the required gate of this part structural complexity, installation and the operation degree of difficulty, still probably bring design advantage to the size of gas tightness shell simultaneously to a certain extent.

In some examples, the airtight enclosure may be manufactured and machined in several segments. Each segment being several meters in length. Each segment is of a box structure. The whole airtight shell can be formed by splicing a plurality of box bodies front and back. The segments are spliced by front and rear flanges, and sealing rubber pads are arranged between the flanges.

In addition, for the actual process of manufacturing and using the equipment, the airtight shell, the two gas replacement chambers and the kiln body 4 are used for sealing all holes before coating, then the whole body is subjected to pressure test, and the airtight equipment is used after the test meets the airtight operation requirement.

In summary, the tunnel kiln provided in the present application example can achieve better air tightness, and at the same time, can ensure smooth proceeding of heat treatment or thermochemical treatment operation, thereby achieving high-efficiency and high-quality production. In some specific alternative examples, the tunnel kiln can be used as a completely airtight type wheel rail type tunnel kiln, which can realize smooth operation when the kiln car enters the kiln body 4 from the kiln head and moves out of the kiln body 4 from the kiln tail, and a special heat treatment or thermochemical treatment process atmosphere can be used in the kiln body.

In order to make the solution easier for a person skilled in the art to understand and implement, an exemplary description will be given below of the manner of use thereof, and mainly with respect to the movement path of the kiln car for transporting material.

Fig. 1 shows the kiln car in a different position during the transport. The first position 1a, the second position 1b, the third position 1c and the fourth position 1d of the kiln car are respectively marked as the kiln car.

1. Kiln car enters the first gas displacement chamber 24

With the first rear shutter 7 closed, the first front shutter 5 is opened. Then, the first transfer mechanism in the first gas replacement chamber 24 is activated, and moves in the direction of the first front gate 5 of the first gas replacement chamber 24, and abuts against a rail (not shown) outside the first inlet of the first gas replacement chamber 24. Subsequently, a first drive mechanism (mainly a first tow chain) moves the first position 1a of the kiln car outside the first entrance to a first transfer mechanism. Then the first drag chain in the first transfer mechanism and the first driving mechanism retreats to the designated position, and then the first front gate 5 is closed.

2. Displacing gas from the first gas displacement chamber 24

When the kiln car enters the first gas replacement chamber 24 and the first front gate 5 and the first rear gate 7 are both in the closed state, the gas in the first gas replacement chamber 24 is replaced with the atmosphere in the tunnel of the kiln body 4.

3. The kiln car enters the tunnel of the kiln body 4

The first front gate 5 is closed, the first rear gate 7 is opened, the first transfer mechanism 12 is started and moves towards the first rear gate 7 until the first front gate is in butt joint with the track 15 at the kiln head of the kiln body 4. Then, the hydraulic thruster in the first driving mechanism pushes the kiln car to the track 15 of the kiln head so as to enter the kiln body 4, so that the kiln car is in the state of the second position 1b of the kiln car, and further, the kiln car can be in the state of the third position 1c of the kiln car through the continuous feeding of the kiln car. At the same time, the hydraulic pusher in the first driving mechanism and the first transfer mechanism are retracted to the specified position, and then the first rear shutter 7 is closed.

4. Second gas replacement chamber 25 gas replacement

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

5. The kiln car enters the second gas displacement 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 located in the second gas replacement chamber 25 is started to move towards the second front gate 9 until the second front gate is butted with the track 15 at the kiln tail of the kiln body 4. The second driving mechanism (second front tow chain 22) in the second gas replacement chamber 25 moves the kiln car on the rail 15 at the kiln tail of the kiln body 4 onto the second transfer mechanism to enter the second gas replacement chamber so as to be in the state of the kiln car fourth position 1 d. At the same time, the second transfer mechanism and the second drive mechanism are retracted to the specified positions, and then the second front shutter 9 is closed.

6. The kiln car leaves the second gas displacement chamber 25

When the second front gate 9 is closed, the second rear gate 10 is opened, and the second transfer mechanism in the second gas replacement chamber 25 is started and moved in the direction of the second rear gate 10 until it abuts against the outside-kiln rail (not shown) outside the second gas replacement chamber 25. Then, the second driving mechanism (second rear tow chain 23) moves the kiln car from the second transfer mechanism to the out-of-kiln track outside the second gas replacement chamber 25. And, the second rotating mechanism and the second driving mechanism are retreated to the initial position, and then the second rear gate 10 is closed.

The detailed procedure for entering the tunnel kiln by the kiln car is explained below.

The kiln car waits on the out-of-kiln track outside the first gas displacement chamber 24. The out-of-kiln track is matched to the tunnel kiln arrangement based on the convenience of kiln car transport. Or, according to different kiln cars, the out-kiln track is not required to be arranged.

The first front gate 5 of the first gas replacement chamber 24 is opened (while the first rear gate 7 is kept closed), and the track of the first transfer mechanism is driven by the gear to be butted against the out-of-kiln track outside the first gas replacement chamber 24. The first tow chain 13 in the first gas displacement chamber 24 is extended to tow the kiln car outside the kiln into the track of the first gas displacement chamber 24 and the kiln car is stopped at a designated position under the control of the sensor. When the out-of-kiln track is not provided, the kiln car may be pushed or "run" itself into the first gas displacement chamber.

After the position is determined by the sensor, the first front gate 5 is closed and locked. Then the first three-way vacuum valve 20 is opened, the first vacuum pump 6 pumps the air in the first gas replacement chamber 24, the first front gate 5 and the first rear gate 7 are firmly sucked, then the first three-way vacuum valve 20 closes the valve connected with the vacuum pump, and the other end is opened to introduce the gas which is the same as or similar to the atmosphere in the furnace or inert gas to carry out gas filling and purging on the replacement chamber.

After the air charging and purging are completed, the first three-way vacuum valve 20 does the reverse action, the vacuum pump is started again to vacuumize the replacement chamber again, and after the gas replacement for a plurality of times, the atmosphere in the first gas replacement chamber 24 is consistent with the atmosphere in the tunnel of the kiln body 4. The first rear shutter 7 is opened (while the first front shutter 5 remains closed). The first front gate 5 and the first rear gate 7 of the first gas replacement chamber 24 have interlocking protection to ensure that the inner and outer gates do not open simultaneously.

After the first rear gate 7 is opened, the track of the first transfer mechanism is in butt joint with the track 15 in the kiln head of the kiln body 4 under the driving of the gear. The first tow chain 13 pushes the kiln cars to a position close to the kiln cars in the tunnel of the kiln body 4. At this time, the ram 29 of the kiln car is positioned above the hydraulic thruster 14, and the first tow chain 13 is retracted and the kiln car is pushed by the servo-controlled hydraulic thruster 14.

When the kiln car is not in the kiln body temporarily, the kiln car is pushed by the hydraulic propeller 14 to enter the kiln body. At the same time, the hydraulic thruster 14 stops and retreats back to the original position.

Or, when the kiln car is already in the kiln body, the kiln car is pushed by the hydraulic pusher 14 to enter the kiln body, and is contacted with the existing kiln car in the tunnel of the kiln body 4, and the existing kiln car is pushed, and the newly entered kiln car reaches the position of the original kiln car. At the same time, the hydraulic thruster 14 stops and retreats back to the original position.

In addition, the kiln car is moved to the position of the preceding kiln car. When the hydraulic thruster 14 starts to retreat, the first transfer mechanism also retreats, all in place the first rear gate 7 falls down and is locked. The first gas displacement chamber 24 enters an idle state and may be ready for the next kiln car.

The detailed steps of the removal of the kiln car from the tunnel kiln are illustrated by the following explanation.

When the second gas replacement chamber 25 is empty and has no kiln car inside, both the second front gate 9 and the second rear gate 10 are closed. The atmosphere inside the second gas replacement chamber 25 has been replaced by the same atmosphere as the inside of the tunnel of the kiln body 4.

When the first front gate 5 of the first gas replacement chamber 24 is closed and the first rear gate 7 is opened and the kiln car is ready to enter the head of the kiln body 4, the second front gate 9 of the second gas replacement chamber 25 is also opened (the second rear gate 10 is kept closed).

Meanwhile, the rails of the second transfer mechanism in the second gas replacement chamber 25 are butted against the rails 15 in the kiln tail of the kiln body 4 under the driving of the gears. The second front tow chain 22 is started and arrives at a designated location to wait for the kiln car to be in place. As the pusher of the first gas displacement chamber 24 advances the kiln car to the position of the preceding kiln car, the last kiln car in the tunnel of the kiln body 4 is also ejected by the kiln car behind on the track and passes through the second front gate 9 of the second gas displacement chamber 25.

The second front tow chain 22 activates the tracks of the second transfer mechanism that tows the kiln car into the second gas displacement chamber 25. After the sensor determines that the kiln car stops to the designated position, the second transfer mechanism and the second front drag chain 22 return, and then the second front gate 9 is closed and locked.

After the second front gate 9 is closed, the kiln car is in place. At this time, the second rear gate 10 of the second gas replacement chamber 25 is opened, and the track of the second transfer mechanism in the second gas replacement chamber 25 is brought into abutment with the track outside the second gas replacement chamber 25 by the driving of the gears. The second rear drag chain 23 drives the kiln car from the track of the second transfer mechanism to the out-of-kiln track outside the second gas displacement chamber 25. After the sensor determines that the kiln car enters the designated position, the second transfer mechanism and the second rear drag chain 23 return, and then the second rear gate 10 is closed and locked.

Then, the second gas replacement chamber 25 is subjected to gas purging in accordance with the same procedure as that of the first gas replacement chamber 24, and the atmosphere in the second gas replacement chamber 25 is changed to be in conformity with the atmosphere in the kiln body 4 for the next same operation. For example, the second three-way vacuum valve 21 is opened and the air is pumped by the second vacuum pump 8.

In connection with the above explanation of the movement of the kiln car, in a specific application example, the operation and use of the tunnel kiln can be seen as follows.

Firstly, the temperature of each section in the tunnel of the kiln body 4 is raised to the preset temperature of the process, and then the required process gas is introduced and the flow is regulated.

Secondly, after the atmosphere and the temperature in the tunnel are adjusted to the corresponding process requirements, the kiln car is transported in the following way.

The kiln car (the saggar carries the operation object) loaded with the saggar sequentially penetrates into a first transfer mechanism in a first gas replacement chamber of the tunnel kiln.

The kiln car is then pushed into the track in the kiln body 4 by the first drive mechanism of the first gas displacement chamber. The kiln car entering from the back can tightly prop against the kiln car in front of the track, and the kiln car in front is pushed forwards until the whole tunnel is filled with the kiln cars.

The kiln car at the end of the kiln is then drawn by the second drive mechanism in the second gas displacement chamber 25 onto the second transfer mechanism in the second gas displacement chamber. And then pushed out of the second gas replacement chamber into the post-process treatment region.

And simultaneously, the kiln car of the first gas replacement chamber enters the kiln head to push the kiln car queue to move forwards. Or the kiln car at the tail of the kiln enters the second gas displacement chamber 25, and the kiln car at the head of the kiln enters the first gas displacement chamber.

Through the steps, the material to be calcined can pass through different temperature areas in the tunnel, and the calcining process is completed. In the actual operation process, in order to improve the efficiency, two kiln cars 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. And after each kiln car is pushed into the kiln body 4, the next kiln car is pushed into the kiln after the kiln car is stopped for a period of time. The train of kiln cars in the tunnel kiln moves forward. The pause time is determined by the effective length of the kiln, the temperature zone setting, the process requirements and the like.

Through the above operation, the heat treatment of calcining the positive electrode material such as a lithium ion battery can be performed by using a tunnel kiln, thereby satisfying the requirement of introducing and maintaining a special atmosphere during calcining. Of course, the tunnel kiln can also be used for the production of other products, such as powder metallurgy, alloy processing, and sintering of ceramic materials.

As an example of an application, a conveying method carried out with the tunnel kiln described above is given by way of example.

The calcination method includes the following steps.

And S101, providing a working environment in the tunnel of the kiln body 4 when the first outlet and the second inlet are in a closed state.

When the first rear gate 7 and the second front gate 9 are closed, the tunnel of the kiln body 4 is in a sealed state, so that a working environment can be provided in the tunnel. The working environment can be different according to different using modes of the tunnel kiln. For example, when a tunnel kiln is used as the calcination apparatus, the working environment is, for example, a calcination atmosphere/process atmosphere 18 (shown in fig. 1), a calcination temperature, and the like.

Step S102, the carrier outside the tunnel kiln is transferred from the opened first entrance to the first transfer mechanism 12 and transferred to the first selected position in the first gas replacement chamber 24 by the first driving mechanism, wherein the carrier is loaded with the operation object.

In the example, a kiln car is loaded with a stack of saggars 2 for containing work objects such as battery material or inorganic material powder or products.

The carrier may be a kiln car or other type of transport device suitable for use in existing tunnel kilns. In different examples, the vehicle may have different implementations. The specific implementation manner of the carrier needs to be adjusted according to the structural manner of the track for the carrier to "walk" in the tunnel kiln, which is not specifically limited in this application.

To facilitate kiln car movement, the carriers outside the tunnel kiln may typically use kiln outer rails. I.e., the carriers outside the tunnel kiln, can be transported into the first gas displacement chamber 24 via the external kiln track. Specifically, the first drive mechanism moves the carriers outside the tunnel kiln to the first transfer mechanism 12 within the first gas displacement chamber 24. The first transfer mechanism 12 moves together with the carrier.

Step S103, the first inlet is closed, the atmosphere in the first gas replacement chamber 24 is replaced, and then the first outlet is opened, and the carrier is transferred to the second selected position of the tunnel of the kiln body 4 through the first outlet.

After the carrier has been moved into the first gas displacement chamber 24, it will subsequently be transferred into the tunnel of the kiln body 4. Thus, the introduction of undesired gases through the first gas displacement chamber 24 into the tunnel of the kiln body 4 can be avoided by displacing the gas in the first gas displacement chamber 24 to a desired atmosphere.

In the illustrated example, the gates at both ends of the first gas displacement chamber 24 are closed, thereby closing the first inlet and the first outlet and closing the interior of the first gas displacement chamber 24. To this end, the atmosphere in the first gas displacement chamber 24 may be displaced by a vacuum system or other gas extraction and injection equipment to be the same as the atmosphere in the tunnel of the kiln body 4.

After the atmosphere in the first gas displacement chamber 24 is displaced, the carrier is driven by the first driving mechanism into the tunnel of the kiln body 4. The carriers in the tunnel may be moved in the tunnel by the carriers that are subsequently moved from the first gas displacement chamber 24 by the first driving mechanism. After the carrier enters the tunnel of the kiln body 4, the work object (such as the battery material) in the carrier is subjected to heat treatment or thermochemical treatment, such as calcination, etc., in the tunnel.

Step S104 is to replace the atmosphere in the second gas replacement chamber 25 with the second inlet and the second outlet closed, and then to transfer the carrier from the opened second inlet to the second transfer mechanism and to a third selected position in the second gas replacement chamber 25.

After the work object on the carrier is processed in the tunnel, the work object is transported into the second gas replacement chamber 25. In order to avoid the influence of the gas in the second gas replacement chamber 25 on the atmosphere in the tunnel, the atmosphere in the second gas replacement chamber 25 needs to be replaced. In other words, the gas is replaced before the carrier is transferred. That is, the second inlet and the second outlet are closed, and then the atmosphere in the second gas replacement chamber 25 is replaced by the gas suction and injection device of the second gas replacement chamber 25 so as to be the same as the atmosphere in the tunnel of the kiln body 4.

And S105, closing the second inlet, and transferring the carrier out of the tunnel kiln through the opened second outlet.

After the carrier has entered the second gas displacement chamber 25, the second inlet is closed, thereby isolating the second gas displacement chamber 25 from the tunnel of the kiln body 4. Therefore, the gas in the second gas replacement chamber 25 does not interfere with the gas in the tunnel of the kiln body 4. At this point, the carriers may be transferred outside the tunnel kiln. For example, the second transfer mechanism interfaces with the extrakiln track outside the tunnel kiln, and then the second drive mechanism drives the carrier to the extrakiln track. The second outlet may then be closed.

If it is subsequently necessary to continue the introduction of the carrier, the second gas displacement chamber 25 can also be gas-displaced so that the carrier subsequently pushed out of the tunnel of the kiln body 4 can be introduced therein for the next identical work flow.

It should be noted that although the above-described operations implement the respective steps in the given steps, this is not intended to limit the order in which each of the steps can be implemented only in the above-described order. In other exemplary steps, some of the steps may be adjusted as appropriate to meet specific operational requirements.

For example, in the present application, the gas replacement in the first gas replacement chamber and the gas replacement in the second gas replacement chamber may be performed in other examples, alternatively, simultaneously, in addition to the above-described sequence of steps. For example, the gas in the first gas replacement chamber may be replaced at step S103, and the gas in the second gas replacement chamber may be replaced simultaneously. Alternatively, in another example, when the operation environment is provided in the tunnel of the kiln body in step S101, the gas in the second gas replacement chamber 25 may be replaced simultaneously.

The above description is only a preferred embodiment of the present application and is not intended to limit the present application, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims (10)

1. A tunnel kiln, comprising:

the kiln body is provided with a tunnel positioned inside, and the tunnel is provided with a track;

a first gas displacement chamber having a first inlet and a first outlet, the first gas displacement chamber being connected to one end of the kiln body through the first outlet;

a second gas displacement chamber having a second inlet and a second outlet, the second gas displacement chamber being connected to the other end of the kiln body through the second inlet;

the gate can be opened and closed selectively, and the first inlet, the first outlet, the second inlet and the second outlet are respectively provided with the gate;

a kiln car configured to be capable of passing through the first gas displacement chamber, the kiln body, and the second gas displacement chamber.

2. The tunnel kiln of claim 1, comprising a gas-tight enclosure connected to the gate and enclosing the kiln body, the first gas displacement chamber and the second gas displacement chamber.

3. The tunnel kiln of claim 1, wherein the first gas displacement chamber has a first transfer mechanism independent of and engaged with the track, a first drive mechanism for driving movement of the kiln car, and the second gas displacement chamber has a second transfer mechanism independent of and engaged with the track, a second drive mechanism for driving movement of the kiln car.

4. The tunnel kiln of claim 3, wherein both ends of the rail are detachably dockable with the first transfer mechanism and the second transfer mechanism, respectively.

5. The tunnel kiln of claim 3 or 4, wherein the kiln car is selectively movable in any one of the first transfer mechanism, the second transfer mechanism and the track.

6. The tunnel kiln of claim 5, wherein damping mechanisms are disposed within the first gas displacement chamber and the second gas displacement chamber, respectively, for engagement with the kiln car.

7. The tunnel kiln of claim 1, wherein the first gas displacement chamber has a preheating device therein;

and/or the second gas displacement chamber has a cooling device therein.

8. The tunnel kiln of claim 1, wherein the side walls of the kiln body have heaters.

9. The tunnel kiln of claim 1 or 8, wherein the side walls of the kiln body are provided with gas injection means.

10. The tunnel kiln of claim 1, wherein the first gas displacement chamber and the second gas displacement chamber are each independently provided with a vacuum device.

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