Muffle furnace automatic sample feeding and discharging device and method for bituminous coal caking index determination

Abstract

The invention discloses a muffle furnace automatic sample feeding and discharging device and method for bituminous coal caking index determination, and relates to the technical field of muffle furnaces, and the muffle furnace automatic sample feeding and discharging device specifically comprises a bearing base body, a control module, a muffle furnace, a transferring unit, a temporary storage unit, a sample feeding and discharging execution unit and a cooling unit, during operation, the temperature needs to be increased to 850 + / -5 DEG C through initialization, heat preservation is carried out, the sample is conveyed to the execution unit through the conveying unit, the sample is precisely conveyed into the furnace through the execution unit for dry distillation, automatic sampling is carried out after dry distillation, natural air cooling is carried out firstly, then forced cooling is carried out, and circulation operation is carried out. The temperature fluctuation in the furnace can be controlled within a qualified range, the potential safety hazard of manual high-temperature operation is avoided, the accuracy and repeatability of detection data are guaranteed, and the large-scale detection efficiency is greatly improved.

Description

Technical Field

[0001] This invention relates to the field of muffle furnace technology, and more specifically to an automatic sample feeding and discharging device and method for determining the caking index of bituminous coal in a muffle furnace. Background Technology

[0002] The bituminous coal caking index (G value) is the core indicator for evaluating the caking ability of bituminous coal. The determination must strictly follow the national standard (such as GB / T5447). After the prepared coal sample is mixed with special anthracite, it is placed in a crucible and placed in a muffle furnace at a high temperature of 850℃ to complete the dry distillation reaction.

[0003] Traditional methods for determining the G-value of bituminous coal rely heavily on manual operation in the muffle furnace sample loading and unloading process. Operators must transfer, place, and retrieve crucible samples at the high-temperature furnace opening, which is not only labor-intensive but also poses a safety hazard of burns. Furthermore, manual operation makes it difficult to accurately control the timing of sample delivery and retrieval, and even slight deviations in the distillation time can directly affect the accuracy and repeatability of the G-value measurement data. In addition, the manual single-batch operation mode is inefficient and cannot meet the needs of large-scale, batch coal quality testing in laboratories, thus hindering the intelligent upgrading process of coal quality analysis laboratories.

[0004] Currently, although some automated equipment exists (such as publication numbers CN218723044U and CN210832995U), there is a lack of mature solutions that can seamlessly connect with high-temperature muffle furnaces to achieve continuous, accurate, and fully automated loading and unloading of bituminous coal G-value samples. It is difficult to solve key technical problems such as sample transfer and stable maintenance of furnace temperature under high-temperature conditions. In this regard, the present invention proposes a solution. Summary of the Invention

[0005] The purpose of this invention is to provide an automatic sample loading and unloading device and method for determining the caking index of bituminous coal in a muffle furnace, which realizes full automation of the high-temperature sample loading and unloading process for G-value determination, ensures the accuracy of test data, and improves operational safety and testing efficiency. The device can be operated independently as a standalone unit or as a functional unit of a fully functional unmanned G-value determination system.

[0006] The objective of this invention can be achieved through the following technical solution: an automatic sample loading and unloading device for determining the caking index of bituminous coal, comprising a supporting substrate, a control module, and a muffle furnace, a transfer unit, a temporary storage unit, a crucible sample assembly, a sample loading and unloading execution unit, and a cooling unit. The muffle furnace is equipped with a muffle furnace door. The temporary storage unit is used to store the crucible sample assembly. The sample loading and unloading execution unit is used to drive the crucible sample assembly into and out of the muffle furnace. The transfer unit is used to transfer the crucible sample assembly between the temporary storage unit, the sample loading and unloading execution unit, and the cooling unit. The control module is electrically connected to all the above units, and the control module controls the muffle furnace to switch to a constant power output mode when the furnace opening is open.

[0007] The device is further configured as follows: an automatic sample loading and unloading device for a muffle furnace for determining the caking index of bituminous coal, comprising a support base, a control module, and a muffle furnace, a transfer unit, a temporary storage unit, a crucible sample assembly, a sample loading and unloading execution unit, and a cooling unit. The muffle furnace is equipped with a muffle furnace door. The temporary storage unit is used to store the crucible sample assembly. The sample loading and unloading execution unit is used to drive the crucible sample assembly into and out of the muffle furnace. The transfer unit is used to transfer the crucible sample assembly between the temporary storage unit, the sample loading and unloading execution unit, and the cooling unit. The control module is electrically connected to the above units, and the control module controls the muffle furnace to switch to a constant power output mode when the furnace opening is open.

[0008] The sample loading and unloading execution unit is further configured as follows: the sample loading and unloading execution unit is a sample carrier unit and includes a lifting mechanism, a horizontal motion mechanism and a sample carrier unit worktable. The lifting mechanism and the horizontal motion mechanism form a three-dimensional transfer action. The sample carrier unit worktable is provided with a positioning structure that cooperates with the crucible sample assembly.

[0009] Further configured as follows: The lifting mechanism includes a lifting servo motor, a fixing component, a bearing seat, a coupling, a reducer, a ball screw, a ball screw nut, an aluminum alloy frame, and a support frame. The lifting servo motor drives the ball screw to rotate through the reducer. The ball screw nut is fixedly connected to the support frame. A sample carrier seat is connected to the top of the support frame and drives the sample carrier seat to move vertically. The horizontal motion mechanism includes a linear servo motor and a linear module. The sample carrier seat is fixed on the slider of the linear module and forms a horizontal reciprocating motion. The sample carrier unit worktable includes a bearing rod fixedly connected to the sample carrier seat, a high-temperature rod connected to the front end of the bearing rod, and a positioning clip set at the end of the high-temperature rod. The positioning clip is used to fix the crucible sample assembly.

[0010] The cooling unit is further configured to include a cooling base, a heat sink, a positioner, and a detection switch. The positioner is used to coordinate with the positioning action of the crucible sample assembly. The detection switch is linked with the heat sink and activates the heat sink after detecting that the sample is in place.

[0011] The lifting mechanism is further configured to include an upper limit sensor and a lower limit sensor, which are respectively positioned at the upper and lower limits of the lifting stroke and are used to trigger a stop signal for the lifting motion.

[0012] Further configuration: the positioning card has an elastic buffer layer on its inner side; the control module includes a PLC controller, a human-machine interface module, and an alarm module; the PLC controller includes a timing module and a motion control module; the alarm module issues an audible and visual alarm when there is over-temperature, over-range, or sample absence; the muffle furnace door is equipped with a pneumatic or electric drive mechanism and is electrically connected to the control module; and the cooling unit's heat dissipation component is a cooling fan.

[0013] The present invention also proposes an automatic sample loading and unloading method for muffle furnaces for determining the caking index of bituminous coal, comprising the following actions: Initialization preparation stage: The control module is started, the sample entry and exit execution unit is reset, the muffle furnace is heated to 850℃±5℃ and held for ≥30min, the crucible sample is transferred to the temporary storage unit, and the in-situ detection sensor feedback signal is detected. Automatic sample feeding stage: The transfer unit grabs the crucible sample from the temporary storage unit and places it in the positioning structure of the sample feeding execution unit. The control module sends a sample feeding command, and the sample feeding execution unit drives the sample to rise to the same height as the furnace opening through the sample feeding command. Furthermore, the muffle furnace switches to constant power mode, the furnace opening opens, the sample inlet / outlet execution unit drives the sample horizontally into the muffle furnace dry distillation position and then lowers it for placement, and then exits under no-load; the furnace opening closes, the muffle furnace resumes temperature control and starts the dry distillation timer; The horizontal motion mechanism drives the sample carrier to exit the muffle furnace under no-load conditions, the furnace door closes automatically, the muffle furnace returns to the temperature control mode, and the dry distillation timing module starts timing. Automatic sampling stage: When the dry distillation timer ends, the muffle furnace switches to constant power mode and the furnace opening is opened; the sample feeding and discharging unit is unloaded and fed into the muffle furnace, and the positioning structure rises to pick up the sample after aligning with it. The lifting mechanism drives the sample carrier to rise, and after the positioning card fixes the crucible sample, it sends a clamping signal. The horizontal motion mechanism drives the sample carrier to carry the crucible sample out of the muffle furnace, the furnace door closes automatically, and the muffle furnace returns to the temperature control mode. Cooling and transfer stage: The sample entry and exit execution unit drives the sample down to the standby position, and the sample is cooled by natural air cooling for 3-5 minutes. The transfer unit transfers the sample to the positioner of the cooling unit, and the detection switch triggers the heat dissipation component to start, and the sample is forced to cool by air for 10-15 minutes. Cyclic operation phase: After cooling is completed, the transfer unit sends the sample to the next process. The control module determines whether there are unprocessed samples in the temporary storage unit. If so, it returns to the automatic sample delivery phase; otherwise, it stands by.

[0014] The present invention has the following beneficial effects: This is mainly reflected in the fact that automated mechanisms such as robotic units and sample carrier units complete the sample transfer and furnace loading / unloading operations, replacing manual direct operation at the high-temperature furnace mouth. This completely avoids the safety hazard of operators being burned by high temperatures, and at the same time avoids accidents that may be caused by manual contact with high-temperature crucible sample sets. It significantly reduces the operational risks in the bituminous coal caking index determination process. Specifically, it supports continuous and batch processing of multiple batches of samples. The temporary storage unit can be designed as a multi-layer or turntable structure, which can temporarily store multiple crucible sample sets at the same time. With the automated flow of the transfer unit and the sample loading / unloading execution unit, it realizes the fully automated cycle operation from sample temporary storage, furnace loading / unloading, cooling to transfer to the next process.

[0015] To supplement the above: the key lies in accurately controlling the timing of sample delivery, sampling, and dry distillation. Furthermore, when the furnace door is opened, the muffle furnace switches to constant power output mode, effectively suppressing temperature fluctuations within the furnace (temperature fluctuations throughout the process can be controlled within ±3℃, far superior to the temperature fluctuation range of manual sample delivery). Compared to the data deviation problems caused by the difficulty in accurately controlling time and temperature during manual operation, this significantly improves the accuracy and repeatability of the bituminous coal caking index measurement results. Secondly, the lifting mechanism is equipped with upper and lower limit sensors, which can trigger a stop signal for the lifting movement, forming double safety protection. An elastic buffer layer is set inside the positioning card to prevent damage to the crucible sample assembly during clamping. The alarm module will issue audible and visual alarms when there is over-temperature, over-range, or sample shortage. Multiple protection mechanisms ensure the stability and reliability of equipment operation, reducing the frequency of equipment downtime. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a front view of the overall structure of the automatic sample feeding and discharging device for determining the caking index of bituminous coal proposed in this invention. Figure 2 for Figure 1 Top view of the structure; Figure 3 For the present invention Figure 1 Schematic diagram of the intermediate sample carrier unit; Figure 4 For the present invention Figure 1 Schematic diagram of the intermediate cooling unit; Figure 5 For the present invention Figure 1 A schematic diagram of the trapezoidal speed curve during the operation of the servo motor; Figure 6 This is a flowchart of the automatic sample feeding and discharging method for determining the caking index of bituminous coal proposed in this invention. Figure 7 This is a flowchart of the automatic sample feeding and discharging method for muffle furnace used to determine the caking index of bituminous coal proposed in this invention. Figure 8 This is a schematic diagram showing the operating direction of the sample carrier unit of the present invention.

[0018] In the diagram: 1. Cooling fan; 2. Cooling unit; 2.1. Cooling base; 2.2. Detection switch; 2.3. Positioner; 3. Workbench; 4. Robot unit; 5. Sample carrier unit; 5.1. High-temperature rod; 5.2. Bearing rod; 5.3. Sample carrier holder; 5.4. Linear servo motor; 5.5. Linear module; 5.6. Fixing component; 5.7. Bearing seat; 5.8. Reducer; 5.9. Lifting servo motor; 5.10. Base; 5.11. Coupling; 5.12. Positioning clip; 5.13. Support frame; 5.14. Ball screw nut; 5.15. Aluminum alloy frame; 5.16. Lower limit sensor; 5.17. Upper limit sensor; 5.18. Ball screw; 6. Buffer area; 7. Crucible sample assembly; 8. Robot base; 9. Sample carrier unit workbench; 10. Muffle furnace; 10.1. Muffle furnace door. Detailed Implementation

[0019] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] Example 1: This example focuses on the feeding and discharging process during muffle furnace operation, primarily used to automate the entire high-temperature sample feeding and discharging process for G-value determination. This ensures the accuracy of test data, improves operational safety and testing efficiency. The device can operate independently or serve as a functional unit in a fully automated, unmanned G-value determination system. The following technical solution is proposed: Reference Figures 1-5 The automatic sample loading and unloading device for muffle furnace used for determining the caking index of bituminous coal in this embodiment includes a support base, a control module, and a muffle furnace, a transfer unit, a temporary storage unit, a crucible sample assembly, a sample loading and unloading execution unit, and a cooling unit that are adapted and installed. The muffle furnace is equipped with a muffle furnace door. The temporary storage unit is used to store the crucible sample assembly. The sample loading and unloading execution unit is used to drive the crucible sample assembly into and out of the muffle furnace. The transfer unit is used to transfer the crucible sample assembly between the temporary storage unit, the sample loading and unloading execution unit, and the cooling unit. The control module is electrically connected to the above units, and the control module controls the muffle furnace to switch to constant power output mode when the furnace opening is opened.

[0021] Operating principle explanation: A brief explanation of the specific operation process: First, the control module completes self-test, the sample carrier unit 5 is reset to the standby position, the muffle furnace 10 starts to heat up and is kept at 850℃±5℃ for 40 minutes, the robot unit 4 sequentially transfers several sets of prepared crucible sample groups 7 to the turntable buffer area 6, and the positioning sensor feeds back the positioning signal of all samples. During the automatic sample delivery stage, robot unit 4 picks up crucible samples 7 one by one from buffer area 6 and places them on positioning card 5.12 of sample carrier unit 5. The lifting servo motor 5.9 of sample carrier unit 5 drives sample carrier frame 5.3 to raise the sample to the same height as the furnace opening. The muffle furnace 10 switches to constant power mode, the muffle furnace door 10.1 opens automatically, and linear servo motor 5.4 drives linear module 5.5 to send the sample into the furnace dry distillation position at high speed according to the trapezoidal speed curve. The lifting servo motor 5.9 drives sample carrier frame 5.3 to descend and place, then exits without load. The muffle furnace door 10.1 closes, the muffle furnace 10 resumes temperature control and starts dry distillation timing. The temperature fluctuation inside the furnace is controlled within ±3℃ throughout the process, which is far better than the temperature fluctuation range of manual sample delivery. After the distillation timer finishes, the automatic sampling stage begins. The muffle furnace 10 switches to constant power mode again, the muffle furnace door 10.1 opens, and the sample carrier unit 5 enters the furnace unloaded. The positioning card 5.12 aligns with the crucible sample group 7 and rises to pick it up. After the positioning card 5.12 sends a clamping signal, the sample carrier unit 5 smoothly exits the furnace body with the sample, and the muffle furnace door 10.1 closes. The sample is then naturally cooled by air in the standby position for 4 minutes, and then sent to the cooling unit 2 by the robot unit 4. The detection switch 2.2 triggers the cooling fan to start, and forced air cooling is completed for 12 minutes. The robot unit 4 then sends the cooled sample to the subsequent testing process. After the first batch of samples is processed, the control module detects that there are still unprocessed crucible group samples 7 in the buffer area 6, and automatically returns to the automatic sample feeding stage to start the next batch operation. This part is the basic operation of the feeding and discharging device proposed in this invention.

[0022] Example 2: This example supplements the above-mentioned collaborative operation process of the carrier substrate, transfer unit, sample entry / exit execution unit, cooling unit, and control module: Further integration Figures 1-5 And refer to Figure 6 and Figure 7The supporting base is the worktable 3, and the transfer unit is the robot unit 4. The robot unit 4 is a 6-axis industrial robot, which is fixed on the robot base 8 and then fixed on the worktable 3. The movement range of the robot unit 4 can fully cover the loading and unloading positions of the temporary storage unit, the sample entry and exit execution unit, and the cooling unit 2. Its output end is equipped with a gripping action of the crucible sample group 7, which can stably complete the gripping and transfer of the crucible sample group 7. The temporary storage unit is the buffer area 6, which can be designed as a multi-layer or turntable structure, and can temporarily store multiple crucible sample groups 7 at the same time. The buffer area 6 can also provide feedback on the temporary storage status of the crucible sample group 7, so that the control module can keep track of the sample processing status in real time and provide data support for subsequent cycle operations. The flexible movement of the 6-axis industrial robot combined with the multi-station coverage of the movement range replaces the manual sample transfer operation, which not only avoids the safety risks of manual contact with high-temperature samples, but also improves the efficiency and accuracy of sample transfer. The multi-layer or turntable buffer area 6 realizes the temporary storage of multiple batches of samples, laying the foundation for continuous operation. The sample loading / unloading unit is a sample carrier unit 5, which includes a lifting mechanism, a horizontal motion mechanism, and a sample carrier unit worktable 9. The lifting mechanism and the horizontal motion mechanism form a three-dimensional transfer action. The sample carrier unit worktable 9 is equipped with a positioning structure that works in conjunction with the crucible sample group 7, which can achieve precise loading and transfer of the crucible sample group 7. Specifically, the actions are as follows: S1: Lifting Mechanism: Includes a lifting servo motor 5.9, a fixing component 5.6, a bearing housing 5.7, a coupling 5.11, a reducer 5.8, a ball screw 5.18, a ball nut 5.14, an aluminum alloy frame 5.15, and a support frame 5.13. The lifting servo motor 5.9 drives the ball screw 5.18 to rotate through the reducer 5.8. The ball nut 5.14 is fixedly connected to the support frame 5.13. The top of the support frame 5.13 is connected to a sample holder 5.3, which drives the sample holder 5.3 to move vertically up and down. The lifting mechanism is also equipped with an upper limit sensor 5.17 and a lower limit sensor 5.16, which are respectively located at the upper and lower limits of the lifting stroke and are used to trigger a stop signal for the lifting movement, forming a double safety protection. S2: Horizontal motion mechanism: includes a linear servo motor 5.4 and a linear module 5.5. The sample holder 5.3 is fixed on the slider of the linear module 5.5 and forms a horizontal reciprocating motion. The servo motor driven by it runs according to a preset "trapezoidal" speed curve, which can be found in the following reference. Figure 5 The "V" represented by the Y-axis is mainly used to provide feedback on the speed change during the operation of the horizontal motion mechanism, while the X-axis is used to represent the motion time. S3: Sample Carrying Unit Workbench: Includes a support rod 5.2 fixedly connected to the sample carrier base 5.3, a high-temperature rod 5.1 connected to the front end of the support rod 5.2, and a positioning clip 5.12 located at the end of the high-temperature rod 5.1. The high-temperature rod 5.1 can be made of heat-resistant steel or ceramic-like high-temperature resistant material. The positioning clip 5.12 is used to fix the crucible sample assembly 7, and the inner side of the positioning clip 5.12 is provided with an elastic buffer layer to avoid damage to the crucible sample assembly 7 during clamping. Specifically, as shown in the reference... Figure 8 The horizontal motion mechanism of the sample carrier is activated, driving the sample carrier frame and crucible sample assembly to enter the muffle furnace at high speed in a straight line along direction A. Its movement speed follows a preset "trapezoidal" speed curve to achieve smooth acceleration and deceleration, and finally precise positioning. Then, the sample carrier frame is driven to descend, placing the crucible sample assembly into the muffle furnace. The sample carrier then exits the muffle furnace at high speed in direction B. The coordinated operation of the lifting mechanism and the horizontal motion mechanism enables the precise three-dimensional transfer of crucible sample 7. The "trapezoidal" speed curve control of the servo motor enables smooth acceleration and deceleration, avoiding displacement or overturning of the sample under high-speed motion. The upper limit sensor 5.17 and the lower limit sensor 5.16 eliminate the safety hazard of the lifting mechanism operating beyond its range. The design of the elastic buffer layer further ensures the integrity of crucible sample 7 during the transfer process. The cooling unit 2 includes a cooling base 2.1, a heat sink, a positioner 2.3, and a detection switch 2.2. The heat sink is a cooling fan. The positioner 2.3 is used to coordinate the positioning action of the crucible sample 7. The detection switch 2.2 is linked with the heat sink and activates the heat sink after detecting that the sample is in place. This enables efficient cooling of the high-temperature sample after dry distillation. The linkage design of the detection switch 2.2 enables the automatic start and stop of the cooling fan without manual intervention. The two-stage cooling process of natural air cooling combined with forced air cooling not only ensures the process requirements of sample cooling but also significantly shortens the cooling time and improves the overall operating cycle of the equipment. The control module includes a PLC controller, a human-machine interface module, and an alarm module. The PLC controller is equipped with a timing module and a motion control module. The alarm module issues audible and visual alarms when there is over-temperature, over-range, or sample absence. The muffle furnace door 10.1 is equipped with a pneumatic or electric drive mechanism and is electrically connected to the control module, enabling automatic opening and closing of the muffle furnace door 10.1. The PLC controller can precisely coordinate the operating sequence of each unit to ensure the orderliness of the entire sample entry and exit process. The alarm module greatly improves the safety and reliability of equipment operation, while the human-machine interface module facilitates parameter setting and operating status monitoring for operators.

[0023] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to specific implementations. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. An automatic sample loading and unloading device for determining the caking index of bituminous coal, comprising a support base, a control module, and a compatible muffle furnace, a transfer unit, a temporary storage unit, a crucible sample assembly unit, a sample loading and unloading execution unit, and a cooling unit, characterized in that, The muffle furnace is equipped with a muffle furnace door. The temporary storage unit is used to store crucible samples. The sample entry / exit execution unit is used to drive the crucible samples into and out of the muffle furnace. The transfer unit is used to transfer the crucible samples between the temporary storage unit, the sample entry / exit execution unit, and the cooling unit. The control module is electrically connected to the above units, and the control module controls the muffle furnace to switch to constant power output mode when the furnace opening is opened.

2. The automatic sample feeding and discharging device for muffle furnace used for determining the caking index of bituminous coal according to claim 1, characterized in that, The supporting base is a workbench, the transfer unit is a robot unit, the robot unit is fixed on the supporting base, and the output end of the robot unit is provided with an action component for grasping crucible samples. The temporary storage unit is a buffer area and is used to provide feedback on the temporary storage status of the crucible samples.

3. The automatic sample feeding and discharging device for muffle furnace used for determining the caking index of bituminous coal according to claim 2, characterized in that, The sample loading and unloading execution unit is a sample carrier unit and includes a lifting mechanism, a horizontal motion mechanism and a sample carrier unit worktable. The lifting mechanism and the horizontal motion mechanism form a three-dimensional transfer action. The sample carrier unit worktable is provided with a positioning structure that cooperates with the crucible sample assembly.

4. The automatic sample feeding and discharging device for muffle furnace used for determining the caking index of bituminous coal according to claim 3, characterized in that, The lifting mechanism includes a lifting servo motor, a fixing component, a bearing seat, a coupling, a reducer, a ball screw, a ball screw nut, an aluminum alloy frame, and a support frame. The lifting servo motor drives the ball screw to rotate through the reducer. The ball screw nut is fixedly connected to the support frame. A sample carrier seat is connected to the top of the support frame and drives the sample carrier seat to move vertically. The horizontal motion mechanism includes a linear servo motor and a linear module. The sample carrier seat is fixed on the slider of the linear module and forms a horizontal reciprocating motion. The sample carrier unit worktable includes a bearing rod fixedly connected to the sample carrier seat, a high-temperature rod connected to the front end of the bearing rod, and a positioning clip set at the end of the high-temperature rod. The positioning clip is used to fix the crucible sample assembly.

5. The automatic sample feeding and discharging device for muffle furnace used for determining the caking index of bituminous coal according to claim 4, characterized in that, The cooling unit includes a cooling base, a heat sink, a positioner, and a detection switch. The positioner is used to coordinate with the positioning action of the crucible sample assembly. The detection switch is linked with the heat sink and activates the heat sink after detecting that the sample is in place.

6. The automatic sample feeding and discharging device for muffle furnace used for determining the caking index of bituminous coal according to claim 5, characterized in that, The lifting mechanism is equipped with an upper limit sensor and a lower limit sensor, which are respectively located at the upper and lower limits of the lifting stroke and are used to trigger a stop signal for the lifting motion.

7. The automatic sample feeding and discharging device for muffle furnace used for determining the caking index of bituminous coal according to claim 6, characterized in that, The positioning card has an elastic buffer layer on its inner side. The control module includes a PLC controller, a human-machine interface module, and an alarm module. The PLC controller has a timing module and a motion control module. The alarm module emits an audible and visual alarm when there is over-temperature, over-range, or sample missing. The muffle furnace door is equipped with a pneumatic or electric drive mechanism and is electrically connected to the control module. The cooling unit's heat dissipation component is a cooling fan.

8. An automatic sample loading and unloading method for determining the caking index of bituminous coal using a muffle furnace, comprising the automatic sample loading and unloading device for determining the caking index of bituminous coal as described in claim 7, characterized in that, Includes the following actions: Initialization preparation stage: The control module is started, the sample entry and exit execution unit is reset, the muffle furnace is heated to 850℃±5℃ and held for ≥30min, the crucible sample group is transferred to the temporary storage unit and a feedback signal is received; Automatic sample feeding stage: The transfer unit grabs the crucible sample from the temporary storage unit and places it in the positioning structure of the sample feeding execution unit. The control module sends a sample feeding command, and the sample feeding execution unit drives the sample to rise to the same height as the furnace opening through the sample feeding command. Furthermore, the muffle furnace switches to constant power mode, the furnace opening opens, the sample inlet / outlet execution unit drives the sample horizontally into the muffle furnace dry distillation position and then lowers it for placement, and then exits under no-load; the furnace opening closes, the muffle furnace resumes temperature control and starts the dry distillation timer; The horizontal motion mechanism drives the sample carrier to exit the muffle furnace under no-load conditions, the furnace door closes automatically, the muffle furnace returns to the temperature control mode, and the dry distillation timing module starts timing. Automatic sampling stage: When the dry distillation timer ends, the muffle furnace switches to constant power mode and the furnace opening is opened; The sample entry / exit unit is unloaded and fed into the muffle furnace. After the positioning structure aligns with the sample, it rises to pick it up. The lifting mechanism drives the sample carrier to rise, and after the positioning card fixes the crucible sample, it sends a clamping signal. The horizontal motion mechanism drives the sample carrier to carry the crucible sample out of the muffle furnace, the furnace door closes automatically, and the muffle furnace returns to the temperature control mode. Cooling and transfer stage: The sample entry and exit execution unit drives the sample down to the standby position, and the sample is cooled by natural air cooling for 3-5 minutes. The transfer unit transfers the sample to the positioner of the cooling unit, and the detection switch triggers the heat dissipation component to start, and the sample is forced to cool by air for 10-15 minutes. Cyclic operation phase: After cooling is completed, the transfer unit sends the sample to the next process. The control module determines whether there are unprocessed samples in the temporary storage unit. If so, it returns to the automatic sample delivery phase; otherwise, it stands by.

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