Automatic method and device for discharging stone coal

Abstract

The application discloses a kind of stone coal automatic discharge method and device in the technical field of coal mill, first, by umbrella-shaped structure in uniform scattering device and layered baffle to the physical dispersion of falling stone coal, inhibit bridge formation from source;Second, by the heat-driven element driven by shape memory alloy set on transfer box and negative pressure pipeline, spontaneous use of material waste heat generates periodic action, realizes passive preventive bridge breaking;At the same time, combined with multi-layer material level sensor group, identify material full and bridge fault state, automatically control gate opening and closing, negative pressure fan start-stop, and trigger the corresponding position of electric drive to actively shock and clear.The whole process of stone coal from receiving, temporary storage, negative pressure conveying to classified storage is unmanned, automated intelligent processing, not only completely eliminates the safety hazard of manual operation, but also ensures the continuous and smooth flow of materials in the whole system through the multi-level collaborative anti-blocking mechanism.

Description

Technical Field

[0001] This invention relates to the field of coal mill technology, and in particular to an automatic method for discharging coke and gravel. Background Technology

[0002] Medium-speed coal mills are core equipment in the pulverizing systems of thermal power plants. They are power machines that use medium-speed rotating grinding components (such as grinding rollers or grinding balls) as the main grinding tools, utilizing pressure and shear force to crush and grind raw coal into pulverized coal on a grinding disc. The working process simultaneously involves drying (introducing hot air) and separation (unqualified coarse powder is separated and returned for regrinding). It can continuously produce qualified pulverized coal with uniform fineness suitable for efficient boiler combustion. It features low energy consumption, low noise, and compact design, making it the most mainstream pulverizing equipment for modern large-scale power plant boilers.

[0003] However, in existing technologies, the discharge and transfer of coal stones from medium-speed coal mills in thermal power plants is considered a low-cost, intermittent, repetitive operation. In actual production, under harsh conditions of high temperature, high dust, and vibration, operators still need to visually determine whether the coal stone box is full by observing the inspection hole, then manually close the door once, manually pull out the full coal stone box, replace it with an empty one, and then manually open the door again. The full coal stone box is then manually transported to the designated collection site by forklift. However, manual transfer of coal stones has the following risks and problems: manual observation is prone to delays and human error; the coal stones discharged from the medium-speed coal mill are hot and dusty, and improper storage can cause burns; if coal stones are not discharged in time, severe blockage of coal stones in the coal mill can occur, causing the differential pressure between the inlet and outlet of the coal mill to rise, which in turn causes the hydraulic cylinder of the coal mill to automatically and rapidly increase the loading force, which in severe cases can cause violent vibration of the coal mill and serious damage to various equipment in the coal mill. Therefore, we propose an automatic method for discharging stone coal. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides an automatic emission method for stone coal. This invention achieves unmanned automation of the entire emission process by deploying multi-layer sensors and intelligent control units, and systematically solves the safety and efficiency problems of manual operation, as well as the bridging and blockage problems of materials during collection, temporary storage and transportation by adopting a multi-level composite bridging strategy.

[0005] The objective of this invention is achieved as follows: an automatic method for discharging gravel and coal, comprising the following steps: S1, close the second gate at the discharge port of the transfer box, open the first gate at the feed port of the transfer box, receive the stone coal discharged from the corresponding coal mill, use a dispersion device to disperse the landing point of the stone coal, and monitor the stone coal collection progress in real time through the material level sensor group. S2, based on the temperature inside the transfer box and a hybrid bridging strategy, uses a bridging unit to break the bridging phenomenon of the coal stones. The execution of the bridge-breaking unit is coordinated with the temperature and the status of the material level sensor group inside the transfer box; S3, when the level of the stone and coal material triggers the preset conveying signal, the negative pressure conveying process is executed to convey the stone and coal in the transfer box to the transfer device; The negative pressure delivery process is implemented in conjunction with a hybrid bridge-breaking strategy. S4, the transfer device receives stone coal from multiple negative pressure conveyors and continuously guides the stone coal to the main stone coal box through an automatic diversion strategy.

[0006] Optionally, the dispersion device is made of wear-resistant material and includes an umbrella-shaped structure and a baffle. The umbrella-shaped structure is located directly below the stone and coal discharge outlet, and the umbrella-shaped structure is provided with a flow guiding structure that is distributed in a circular pattern. The umbrella-shaped structure is used to initially break up the falling stones and coal. The baffles are installed on the inner wall of the transfer box, are inclined, and are distributed in layers with staggered positions. The width of the baffles decreases from top to bottom.

[0007] Optionally, the material level sensor group is installed inside the transfer box, below the baffle, and a flexible vibration isolation structure is provided between the material level sensor and the transfer box; The material level sensor group adopts a rotary paddle material level sensor; The material level sensor group includes a low-level sensor, a middle-level sensor, and a high-level sensor; The transfer box has a conical groove inside, and both the low-position sensor and the mid-position sensor are installed in the conical groove. The connection between the conical groove and the inner wall of the transfer box is rounded.

[0008] Optionally, the bridge-breaking unit includes a thermal drive component and an electric drive component, wherein the thermal drive component is disposed on the inner wall of the transfer box and the electric drive component is disposed on the outer wall of the transfer box; The thermal drive component and the electric drive component are evenly distributed and arranged in layers; The push rod structure of the heat-driven component is consistent with the contour of the inner wall of the transfer box; An electric drive unit is disposed below each of the low-position, mid-position, and high-position sensors.

[0009] Optionally, the hybrid bridge-breaking strategy in step S2 is as follows: when the discharge of high-temperature stone coal causes the internal temperature of the transfer box to rise, and the temperature of the shape memory alloy element in the thermal drive component is lower than the phase change threshold, the shape memory alloy element has no shrinkage tension, the built-in reset structure holds the push rod, and the thermal drive component remains in standby state. As the stones and coal gradually accumulate, when the temperature of the shape memory alloy element inside the thermal drive component reaches the phase change threshold, the shape memory alloy element undergoes a phase change, generating a contraction force that overcomes the elasticity of the reset structure, pulls the push rod back, destroys the force support points between the stones and coal, and breaks the overhead structure of the stone and coal pile. When the high-level sensor detects the level of gravel and coal, but the low-level or medium-level sensor does not detect the level of gravel and coal, the electric drive unit is instructed to perform a shock-breaking process on the transfer box.

[0010] Optionally, the process of step S3 is as follows: S31, close the first gate, and after closing, open the second gate to form a closed space between the transfer box and the negative pressure device; The execution of step S31 is based on a preset conveying signal trigger, that is, the low, middle and high level sensors all detect that the material level has been reached and maintained for 3 seconds; S32, start the negative pressure device, and create negative pressure in the negative pressure pipeline connected between the discharge port and the transfer device to transport the stone coal in the transfer box to the transfer device. S33 delivers fresh ambient air to the transfer box through the air intake structure, which cools the internal temperature of the transfer box and the heat-driven components. S34, when the temperature of the shape memory alloy element inside the thermal drive component drops below the phase transition threshold, a phase transition occurs, restoring the soft state. The reset structure releases its elastic force to hold the push rod, scraping away the residual stones and coal on the inner wall of the transfer box. S35, until the high, middle and low level sensors sequentially detect the horizontal departure of the stone and coal material level; S36, repeat S1 to S3.

[0011] Optionally, in step S32, the pressure value of the negative pressure pipeline is monitored in real time during the operation of the negative pressure device. If an abnormal increase in negative pressure is detected, it is determined that a bridge of stones and coal has formed in the transfer box or negative pressure pipeline. The negative pressure device is instructed to stop working. Based on the horizontal position of the stone and coal material level fed back by the material level sensor group, the electric drive unit of the corresponding layer is instructed to perform a shock treatment, and then the S32 process is resumed.

[0012] Optionally, the automatic traffic splitting strategy in step S4 is as follows: S41 monitors the material level status of the main stone and coal bin in real time, and cleans the full main stone and coal bin so that at least one of the main stone and coal bins has enough storage space to hold the stone and coal. There are at least two total stone coal boxes, defined as the first total stone coal box and the second total stone coal box; S42, the transfer device receives the stone coal conveyed by multiple negative pressure conveyors and conveys it to the first total stone coal box through the diversion device; S43, when the high-level sensor in the first main stone and coal box detects that the stone and coal level has reached the target, the diversion device closes the channel connecting to the first main stone and coal box and simultaneously opens the channel connecting to the second main stone and coal box. S44, repeats S41 to S43.

[0013] An automatic stone coal discharge system for implementing the above-mentioned automatic stone coal discharge method includes at least the following device: a transfer box, wherein the top of the transfer box is provided with a feed inlet and the bottom is provided with a discharge outlet, for collecting and transferring the stone coal directly discharged from the coal mill; The transfer box is equipped with a first gate and a second gate at its inlet and outlet, respectively, to control the flow of stones and coal. The main stone coal bin is used to receive and store stone coal discharged from multiple coal mills, providing a capacity buffer for subsequent processing; There are at least two main stone and coal bins for alternating reception of stone and coal to achieve continuous storage; The dispersion device, including an umbrella-shaped structure and baffles, is used to disperse stones and coal. The material level sensor group is installed in the transfer box and the main stone and coal box to monitor the material level of the stone and coal pile in real time; The material level sensor group inside the transfer box includes at least a high-level sensor, a middle-level sensor, and a low-level sensor distributed from top to bottom. At least one high-level sensor is installed in the main stone and coal box to detect the level of stone and coal material. The bridge-breaking unit, located on the transfer box, includes a thermal drive component and an electric drive component; The heat-driven component is installed on the inner wall of the transfer box and can automatically expand and contract in response to temperature changes in order to break bridges and clean the inner wall. The electric drive component is an impact actuator, which generates an impact force by vibrating the outer wall of the transfer box, thereby destroying the bridging structure formed by the pile of stones and coal. The negative pressure conveying unit, including a negative pressure device and a negative pressure pipeline, is used to suck out the gravel and coal in the transfer box and output it to the transfer device. The transfer device is used to receive the stone coal output from multiple negative pressure pipelines and output the stone coal to the main stone coal box through the diversion device; The input end of the diversion device cooperates with the output end of the transfer device to receive the stone coal output from the transfer device, and is provided with at least two output pipes, each output pipe being connected to a total stone coal box, and each pipe being equipped with an electric gate. The control unit is connected to the electric gate signals on the first gate, the second gate, the material level sensor group, the electric drive unit, the negative pressure conveying unit, the transfer device, and the diversion device; The control unit is used to instruct the aforementioned devices to coordinate the opening, closing, and operation of the first gate, the second gate, the bridge-breaking unit, and the negative pressure conveying unit. The control unit performs bridge breaking and conveying control based on the material level sensor group signals in the transfer box, and performs diversion control based on the material level sensor signals in the main stone and coal box.

[0014] Optionally, the thermal drive component includes: a drive cavity, an SMA spring, a return spring, and a push rod; The drive cavity is fixedly installed on the inner wall of the transfer box; The SMA spring and the return spring are coaxially arranged in the drive cavity, with one end of each fixedly connected to the cavity and the other end fixedly connected to the push rod. The push rod is slidably connected to the drive cavity, and the SMA spring and the return spring are both sleeved on the push rod. The extended end of the push rod is a scraper structure that matches the contour of the inner wall of the transfer box. When the temperature of the SMA spring reaches its phase change threshold due to the heat transfer from the high-temperature stones and coal in the transfer box, the SMA spring contracts, overcomes the elastic force of the reset spring, and pulls the push rod back into the drive cavity to destroy the bridging support point of the stones and coal. When the SMA spring cools down to below its phase transition threshold, it returns to a soft state, the reset spring releases its elasticity, and pushes the push rod outward, so that the scraper structure closely adheres to and scrapes the inner wall of the transfer box to remove residual stones and coal.

[0015] Compared with existing technologies, the beneficial effects of this invention are as follows: This invention provides automated and unmanned operation of the entire process of stone coal discharge and transfer, fundamentally solving the safety, efficiency and reliability problems of traditional manual methods. By deploying multi-level material level sensor groups and intelligent control units based on sensor signals, it can accurately and automatically determine the timing of material collection and discharge in real time. By automatically executing the opening and closing of the first and second gates, as well as controlling the negative pressure conveying and the automatic diversion and switching of multiple stone coal boxes, it replaces the operation mode of human observation and manual box changing, realizing unmanned operation of the entire process from receiving, temporary storage, transportation to storage. It not only completely eliminates the safety hazards of manual operation, but also ensures the timeliness and continuity of stone coal discharge through precise and reliable automated control, effectively preventing damage to the coal mill body caused by discharge delays.

[0016] This invention employs a multi-level composite bridging and unblocking strategy to address the bridging and blockage problem that easily occurs during the processing of stone coal. By setting up an umbrella-shaped structure and layered staggered baffles, the natural landing point of the material is forcibly dispersed using physical methods, preventing the formation of a cone-shaped accumulation with a high center and low edges from the source, thus significantly reducing the initial bridging risk. Secondly, it deploys a thermal drive component based on physical phase change and an electric drive component based on intelligent diagnosis. The thermal drive component does not require external commands and directly uses the waste heat of the stone coal itself to drive its embedded shape memory alloy (SMA) element. When the material accumulates and the temperature conduction is in place, it automatically triggers the expansion and contraction action. The electric drive component, as an active intervention method, has its triggering logic strongly coupled with the status of the material level sensor to achieve precise vibration, effectively ensuring the continuous and smooth flow of material in the system. This is a key technical guarantee for achieving fully automated and reliable operation of the entire process. Attached Figure Description

[0017] 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 embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the automatic discharge method for stones and coal provided by the present invention; Figure 2 This is a schematic diagram of the negative pressure conveying process provided by the present invention; Figure 3 This is a schematic diagram of the traffic splitting strategy provided by the present invention; Figure 4 This is a flowchart of the transfer box circulation process provided by the present invention; Figure 5 This is a flowchart of the flow distribution device provided by the present invention. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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] like Figures 1 to 5This invention discloses an automatic method for discharging coking stone. This method is implemented in the coking stone discharge operation of a medium-speed coal mill in a thermal power plant. The main structure of this application consists of a transfer box and its bridging unit located below the slag discharge port of each coal mill. The transfer box serves as an intermediate temporary storage and processing node for coking stone. During system initialization, it is first confirmed that all equipment is in a ready state: the discharge ports of all transfer boxes are kept closed through the second gate, and their inlets, i.e., the first gate, are ready to open; the negative pressure conveying pipelines connected to each transfer box and the end-of-line transfer devices are in a standby state, and at least the total coking stone box is empty.

[0021] The process includes the following steps: S1, closing the second gate at the discharge port of the transfer box, opening the first gate at the feed port of the transfer box, receiving the stone coal discharged from the corresponding coal mill, using a dispersion device to disperse the landing point of the stone coal, and monitoring the stone coal collection progress in real time through a material level sensor group. Furthermore, when the coal mill starts the discharge program, the second gate at the discharge port of the transfer box remains closed, while the first gate at the feed port is open. The coal stones fall from the slag discharge port of the coal mill into the transfer box. At this time, the temperature of the coal stones is usually above 100°C. If the coal stones are allowed to enter the transfer box from the feed port, they will directly form a bridging structure, piling up into a small hill, i.e., high in the middle and low around the edges. Continuous discharge will cause the high-density coal stones in the center to obstruct the subsequent coal stones from falling, resulting in blockage of the discharge port and even damage to the coal mill. Moreover, the conical void formed makes it impossible for the level sensors set at different heights on the box wall, especially the middle level sensor, to accurately reflect the actual material inventory in the box. This seriously interferes with the judgment of the control system, resulting in the inability to execute negative pressure discharge at the accurate time, or premature termination of discharge due to misjudgment, causing blockage or idling of the equipment. It should be noted that bridging is the phenomenon where particulate material forms a stable arch or bridge-shaped structure in a container, which hinders the normal flow of material below it. Therefore, in order to effectively prevent the stones and coal from accumulating at the landing point and forming a high cone, the present invention sets up a set of uniform dispersion devices inside the transfer box; Specifically, the dispersion device is made of wear-resistant material and includes an umbrella-shaped structure and baffles; The umbrella-shaped structure is located directly below the stone and coal discharge outlet, and the umbrella-shaped structure is equipped with a flow guiding structure that is distributed in a circular pattern. The umbrella-shaped structure is used to initially break up falling stones and coal; The baffles are installed on the inner wall of the transfer box, are inclined, and are distributed in layers with staggered positions. The width of the baffles decreases from top to bottom.

[0022] Furthermore, it includes an umbrella-shaped structure and baffles arranged around the inner wall of the transfer box; the umbrella-shaped structure is preferably made of high-chromium wear-resistant cast iron, such as Cr26, and is fixed directly below the stone coal discharge port by a sturdy support rod. The top surface of the umbrella-shaped structure is an upwardly convex cone, and multiple radial ribs are machined on the cone to form a flow guiding structure. During operation, the falling stones and coal first impact the top cone surface, dispersing their kinetic energy. They then slide outwards along the radial ribs, thus achieving initial physical dispersion and directly preventing the accumulation of stones and coal on the high cone. Subsequently, the initially broken stones and coal continue to fall, impacting the baffles arranged on the inner wall. The baffles are also made of wear-resistant steel plates and are fixed to the inner wall of the box at an angle of 30° to 60°. It should be noted that the baffles are arranged in a layered, staggered manner, with 3 to 5 layers from top to bottom. The baffles of adjacent layers do not completely overlap in the horizontal projection, forming an interlacing effect. Furthermore, the width of the baffles decreases from the top layer to the bottom layer. For example, the first layer is 400mm wide, the second layer is 300mm wide, and the third layer is 200mm wide. The specific width of the baffles needs to be determined based on the actual dimensions of the transfer box. Therefore, during the fall, the coal stones are repeatedly deflected by multiple layers of staggered inclined surfaces, and their horizontal momentum is continuously consumed and redistributed. This ultimately allows the coal stones to be spread relatively evenly at the bottom of the transfer box, rather than concentrated in the central area, thus inhibiting the formation of conical piles from the source.

[0023] Specifically, the material level sensor group is installed inside the transfer box, below the baffle, and a flexible vibration isolation structure is installed between the material level sensor and the transfer box; The level sensor group adopts a rotary paddle level sensor, which has good adaptability to dusty environments; The transfer box has a conical groove inside, where both the low-position sensor and the mid-position sensor are installed. The connection between the conical groove and the inner wall of the transfer box is rounded.

[0024] Furthermore, to prevent false alarms or damage caused by the impact of stones and coal and the vibration of the electric drive components on the box, a flexible vibration isolation structure is installed between the sensor and the mounting flange of the transfer box. Preferably, shock-absorbing pads made of fluororubber and high-elasticity stainless steel corrugated pipes are used for connection and sealing; Specifically, the material level sensor group inside the transfer box includes a low-level sensor, a middle-level sensor, and a high-level sensor, which are arranged vertically. Furthermore, in order to optimize the accuracy of material level detection and guide the material flow to the discharge port, the inner wall of the transfer box is designed with a conical groove. The groove structure is set in accordance with the sensor, mainly to prevent falling stones and coal from directly hitting the sensor and causing damage. At the same time, the conical structure can prevent stones and coal from accumulating and getting stuck in the groove. The connection between the conical groove and the transfer box adopts a large-radius smooth transition treatment to eliminate dead corners and further avoid material retention.

[0025] S2, based on the temperature inside the transfer box and a hybrid bridging strategy, uses a bridging unit to break the bridging phenomenon of the coal stones. The execution of the bridge breaking unit is coordinated with the temperature and the status of the material level sensor group inside the transfer box; The bridge-breaking unit includes a thermal drive component and an electric drive component. The thermal drive component is located on the inner wall of the transfer box, and the electric drive component is located on the outer wall of the transfer box. The thermal drive components and the electric drive components are evenly distributed and arranged in layers; The push rod structure of the heat-driven component is consistent with the contour of the inner wall of the transfer box; An electric drive unit is installed below the low-position, middle-position, and high-position sensors.

[0026] Furthermore, the thermally driven component, as the main passive bridge-breaking mechanism, is arranged on the inner wall of the transfer box, and is evenly distributed in layers, with one layer arranged in the conical groove and on the lower side of the high-position sensor, and each layer is evenly distributed. For example, the thermal drive component includes: a drive cavity, an SMA spring, a return spring, and a push rod; The drive chamber is fixedly installed on the inner wall of the transfer box; The SMA spring and the return spring are coaxially arranged in the drive cavity, with one end of each fixedly connected to the cavity and the other end fixedly connected to the push rod. The push rod is slidably connected to the drive cavity. The SMA spring and the return spring are both sleeved on the push rod. The extended end of the push rod is a scraper structure that matches the contour of the inner wall of the transfer box. When the temperature of the SMA spring reaches its phase change threshold due to the heat transfer from the high-temperature stones and coal in the transfer box, the SMA spring contracts, overcomes the elastic force of the reset spring, and pulls the push rod back into the drive cavity to destroy the bridging support point of the stones and coal. When the SMA spring cools down to below its phase transition threshold, it returns to a soft state. The reset spring releases its elasticity, pushing the push rod outward so that the scraper structure closely adheres to and scrapes the inner wall of the transfer box, removing residual stones and coal.

[0027] Specifically, the hybrid bridge-breaking strategy is as follows: when the discharge of high-temperature stone coal causes the internal temperature of the transfer box to rise, and the temperature of the shape memory alloy element in the thermal drive component is lower than the phase change threshold, the shape memory alloy element has no shrinkage tension, the built-in reset structure holds the push rod, and the thermal drive component remains in standby state. As the stones and coal gradually accumulate, when the temperature of the shape memory alloy element inside the thermal drive component reaches the phase change threshold, the shape memory alloy element undergoes a phase change, generating a contraction force that overcomes the elasticity of the reset structure, pulls the push rod back, destroys the force support points between the stones and coal, and breaks the overhead structure of the stone and coal pile. When the high-level sensor detects the level of gravel and coal, but the low-level or medium-level sensor does not detect the level of gravel and coal, the electric drive unit is instructed to perform a shock-breaking process on the transfer box.

[0028] During operation, when the hot coal is discharged, the heat in the transfer box has not yet been fully conducted to the heat drive component in the box wall. The temperature of the SMA element is below its phase transformation threshold. At this time, the SMA element is in the martensitic phase (soft state) and has no contraction force. The elastic force of the return spring keeps the push rod in the extended state, and the heat drive component is in the "standby" state. As high-temperature coal and stones continue to accumulate and exchange heat with the box wall, the heat is conducted through the box wall to the embedded SMA element. When the temperature of the SMA element reaches and exceeds its phase transformation threshold, an austenitic phase transformation occurs, the material contracts, and a strong contraction force is generated. This force overcomes the elasticity of the return spring and pulls the push rod back into the box wall quickly. The sudden retraction of the push rod will directly destroy the force support point between the coal and stone particles at this position, causing some coal and stones to lose support and slide down, which in turn causes more coal and stones to slide down, thereby breaking the existing or soon-to-be-formed overhead structure. Furthermore, the operation of the thermal drive component is based on the waste heat of high-temperature stone coal. Therefore, the phase transition threshold of the SMA spring inside the thermal drive component can be set according to the box temperature, the rate of temperature change, and the stacking speed of stone coal, so that it can perform the bridge breaking operation at the optimal time. For example, under initial operating conditions, the internal cavity temperature of the transfer box is 60°C, which is lower than the SMA spring phase transformation activation threshold of 85°C. The SMA spring maintains a martensitic soft state, and the push rod remains extended and ready. High-temperature gravel and coal are continuously discharged and accumulated layer by layer. As the gravel and coal layer gradually rises until it densely covers the heat-driven components, the solid material continuously conducts heat to the box wall. The SMA spring temperature rises synchronously to the 85°C phase transformation threshold and triggers the austenitic phase transformation. The SMA spring contracts, pulling the push rod back, disturbing the gravel and coal particle support structure, and breaking the bridging structure that is forming. It should be noted that the SMA phase change temperature threshold is not a fixed value. It can be matched and set according to the incoming temperature of the stone and coal, the insulation conditions of the box, the material accumulation rate, and the heat exchange efficiency, so as to accurately control the start-up timing of the bridge breaking mechanism.

[0029] Furthermore, the greatest advantage of thermally driven components lies in achieving energy self-consistency and ultimate reliability: utilizing the inherent waste heat within the system to convert it into kinetic energy for bridge breaking not only saves continuous power consumption, but more importantly, its action is directly coupled with the physical state (temperature, accumulation amount) of the material being processed, achieving the most timely response. That is, the hotter the material and the longer it has been accumulated (meaning a higher risk of bridging), the more inevitable and intense the triggering of thermally driven bridge breaking becomes, fundamentally avoiding bridge breaking failures caused by external sensor failures, signal delays, or logic errors.

[0030] The electric drive components, as active and supplementary bridge-breaking mechanisms, are arranged on the outer wall of the transfer box, and are also evenly distributed in layers. Preferably, a certain interval is maintained below the horizontal height of the low, middle and high position sensors, and a layer of electric drive components is set accordingly; The electric drive unit can be an electromagnetic vibrator or a pneumatic hammer, among other structures. Its triggering logic is strongly correlated with the material level: when the high-level sensor detects that the stone and coal level has reached its installation height (indicating a high level inside the box), but simultaneously the low-level or mid-level sensor (or both) fails to detect a level signal, the system logic determines that severe bridging has occurred in the area between the sensors, causing discontinuity in the level signal. At this point, the control unit immediately instructs the electric drive unit located below the suspected bridging area to activate, performing one or more short, powerful vibrations to break the bridging.

[0031] For example, an electromagnetic vibrator is activated to generate a high-frequency, low-amplitude vibration for 0.5 seconds, or a pneumatic hammer is triggered to strike once, transmitting the vibrational energy to the bridging section through the box wall, causing it to collapse.

[0032] Furthermore, the electric drive unit not only serves as a reliable backup for the thermal drive mechanism, but also enables the system to have preliminary "fault diagnosis" capabilities through the fusion of material level information. Based on the abnormal signal combination of multiple and multi-level sensors, it can proactively identify typical bridging fault modes such as "material is full at the high level but suspended at the middle and low levels".

[0033] Based on this, tiered intervention, rather than blindly breaking the bridge at full power, can improve processing efficiency, save energy, reduce unnecessary impact on the enclosure structure, and extend equipment life.

[0034] S3, when the level of the stone and coal material triggers the preset conveying signal, negative pressure conveying is executed to transport the stone and coal in the transfer box to the transfer device. The negative pressure conveying is implemented in conjunction with a mixed bridge-breaking strategy, specifically as follows: S31, close the first gate, and after closing, open the second gate to form a closed space between the transfer box and the negative pressure device; The execution of step S31 is based on a preset conveying signal trigger, that is, the low, middle and high level sensors all detect that the material level has been reached and maintained for 3 seconds; S32, start the negative pressure device, and create negative pressure in the negative pressure pipeline connected between the discharge port and the transfer device to transport the stone coal in the transfer box to the transfer device. In addition, the pressure value of the negative pressure pipeline is monitored in real time during the operation of the negative pressure device; If an abnormal increase in negative pressure is detected, it is determined that a bridge of stones and coal has formed in the transfer box or negative pressure pipeline. The negative pressure device is instructed to stop working. Based on the horizontal position of the stone and coal material level fed back by the material level sensor group, the electric drive unit of the corresponding layer is instructed to perform a shock treatment, and then the S32 process is resumed.

[0035] S33 delivers fresh ambient air to the transfer box through the air intake structure, which cools the internal temperature of the transfer box and the heat-driven components. S34, when the temperature of the shape memory alloy element inside the thermal drive component drops below the phase transition threshold, a phase transition occurs, restoring the soft state. The reset structure releases its elastic force to hold the push rod and scrapes away the residual stones and coal on the inner wall of the transfer box. S35, until the high, middle and low level sensors sequentially detect the horizontal departure of the stone and coal material level; S36, repeat S1 to S3.

[0036] Furthermore, when the material level monitoring indicates that the amount of stone coal collected has reached the preset conveying conditions, that is, the low, medium and high level sensors all detect that the material level has reached and maintained for 3 seconds, then it is confirmed that the material level is sufficient, and the control system will start the negative pressure conveying process. First, close the first gate at the feed inlet of the transfer box. After it is completely closed and sealed, open the second gate at the discharge outlet. This ensures that a closed conveying space is formed between the transfer box and the subsequent negative pressure pipeline and negative pressure device to prevent air leakage from affecting the establishment of negative pressure. Next, the negative pressure device, such as a Roots vacuum pump or a water ring vacuum pump, is started. The negative pressure device is connected to the inlet of the transfer device through a negative pressure pipeline. When the second gate is opened, the strong negative pressure acts inside the transfer box, drawing out the stones and coal, which then enter the negative pressure pipeline through the discharge port and are transported at high speed to the transfer device by pneumatic conveying. Furthermore, throughout the entire conveying process, the system monitors the pressure value of the negative pressure pipeline in real time. If an abnormal increase in the negative pressure value is detected, this usually indicates the formation of a new stone and coal bridging or blockage at the discharge port, the bottom of the transfer box cone, or the bend in the negative pressure pipeline. At this time, the system will immediately execute the bridge-breaking protection sub-process: instructing the negative pressure device to stop working, and simultaneously, based on the real-time feedback from the material level sensor group (to determine the approximate height at which the blockage may occur), instructing the electric drive component of the corresponding layer to perform a shock treatment. After the shock treatment is completed, the system resumes the operation of the negative pressure device to attempt to clear the blockage; if the negative pressure value is still abnormal, the shock treatment is repeated 1 to 2 times before triggering an alarm.

[0037] During negative pressure transport, the air intake structure on the transfer box, such as the regulating valve with a filter, controlsably introduces air from the environment into the box. It should be noted that the air has two functions: first, to assist in cooling the high-temperature coal and conveying pipelines; and second, and more importantly, to cool the interior and walls of the transfer container, especially to create conditions for the repositioning of the thermally driven components. Furthermore, as the conveying process continues and the fresh air cools, the temperature inside the transfer box decreases. When the temperature of the shape memory alloy element embedded in the thermal drive component drops below its phase transformation threshold, a reverse phase transformation occurs, restoring it to a martensitic soft state. Its contraction tension disappears, and at this time, the previously compressed return spring quickly releases its elastic potential energy, pushing the push rod out and returning it to its initial extended position. During this pushing process, its contour surface, which is consistent with the box wall, scrapes across the box wall surface, removing residual stones and coal that are attached to or stuck on the wall surface.

[0038] The negative pressure conveying continues until the high, middle, and low level sensors sequentially detect that the stone and coal level has moved horizontally away, indicating that the stone and coal in the transfer box has been basically emptied. Subsequently, the system closes the second gate, prepares for the next cycle, and repeats the entire process that started from S1.

[0039] S4, the transfer device receives the stone coal from multiple negative pressure conveyors and continuously guides the stone coal to the main stone coal box through an automatic diversion strategy, specifically: S41 monitors the material level status of the main stone and coal bin in real time, and cleans the full main stone and coal bin so that at least one of the main stone and coal bins has enough storage space to hold the stone and coal. There are at least two total stone coal boxes, defined as the first total stone coal box and the second total stone coal box; S42, the transfer device receives the stone coal conveyed by multiple negative pressure conveyors and conveys it to the first total stone coal box through the diversion device; S43, when the high-level sensor in the first main stone and coal box detects that the stone and coal level has reached the target, the diversion device closes the channel connecting to the first main stone and coal box and simultaneously opens the channel connecting to the second main stone and coal box. S44, repeats S41 to S43.

[0040] Furthermore, the stone coal from multiple coal mills is simultaneously or alternately transported to a central transfer device, such as a rigid conveyor belt, through their respective independent negative pressure conveying pipelines; This invention sets up at least two main coal and stone bins, each equipped with a high-level sensor to monitor the material level status of all main coal and stone bins in real time. For full main coal and stone bins, a cleaning process is implemented, such as truck transportation of slag, to ensure that at any given time, at least one main coal and stone bin has sufficient remaining storage space. For example, when the first main coal and stone bin is about to be full, a cleaning truck is arranged to clean the second main coal and stone bin. During normal operation, the transfer unit receives stone and coal from multiple negative pressure conveyors and guides the material continuously and stably to the first main stone and coal box through the end diversion device, such as a rotary feeder valve with a sluice that can switch directions, or a dual-path pneumatic flap diverter.

[0041] When the high-level sensor in the first main coal and stone box detects that the material level is full, the control system immediately takes action. The diversion device first opens the channel to the second main coal and stone box, and then closes the channel to the first main coal and stone box to prevent blockage of coal and stone transportation, thereby achieving a seamless switch to the standby empty box.

[0042] Subsequently, while the second main coal and stone container is receiving materials, the first main coal and stone container, which is already full, can be emptied. Once the first main coal and stone container is emptied and ready, it becomes the new backup container. When the second main coal and stone container is about to fill up, the diversion device automatically switches back to the first main coal and stone container, and this cycle repeats, forming an automatic relay storage system with two (or more) containers serving as backups for each other, ensuring unmanned and continuous operation of the entire process of coal and stone discharge and processing.

[0043] The stone coal discharge system provided by the present invention includes at least the following device: a transfer box, with a feed inlet at the top and a discharge outlet at the bottom, for collecting and transferring the stone coal directly discharged from the coal mill; The feed inlet and discharge outlet of the transfer box are equipped with a first gate and a second gate, respectively, to control the flow of stones and coal. The main stone coal bin is used to receive and store stone coal discharged from multiple coal mills, providing a capacity buffer for subsequent processing; There are at least two main stone and coal bins for alternating reception of stone and coal to achieve continuous storage; The dispersion device, including an umbrella-shaped structure and baffles, is used to disperse stones and coal. The material level sensor group is installed in the transfer box and the main stone and coal box to monitor the material level of the stone and coal pile in real time; The material level sensor group inside the transfer box includes at least a high-level sensor, a middle-level sensor, and a low-level sensor distributed from top to bottom. At least one high-level sensor should be installed in the main stone and coal box to detect the level of the stone and coal material. The bridge-breaking unit, located on the transfer box, includes a thermal drive component and an electric drive component; The heat-driven component is located on the inner wall of the transfer box and can automatically expand and contract in response to temperature changes to break bridges and clean the inner wall. The electric drive unit is an impact actuator, which generates an impact force by vibrating the outer wall of the transfer box, thereby destroying the bridging structure formed by the pile of stones and coal. The negative pressure conveying unit, including a negative pressure device and a negative pressure pipeline, is used to suck out the gravel and coal in the transfer box and output it to the transfer device. The transfer device is used to receive the stone coal output from multiple negative pressure pipelines and output the stone coal to the main stone coal box through the diversion device; The input end of the diversion device is matched with the output end of the transfer device to receive the stone coal output from the transfer device. It is equipped with at least two output pipes, each output pipe is connected to a main stone coal box, and each pipe is equipped with an electric gate. The control unit is connected to the electric gate signals of the first gate, the second gate, the material level sensor group, the electric drive unit, the negative pressure conveying unit, the transfer device, and the diversion device. The control unit is used to instruct the aforementioned devices and coordinate the opening, closing, and operation of the first gate, the second gate, the bridge-breaking unit, and the negative pressure conveying unit. The control unit performs bridge breaking and conveying control based on the material level sensor group signals in the transfer box, and performs diversion control based on the material level sensor signals in the main stone and coal box.

[0044] In summary, the advantages of this invention are: 1. Through a unique uniform dispersion device and anti-interference material level monitoring, bridging is physically suppressed and accurate status feedback is ensured; 2. By combining the self-driven thermal bridge breaking driven by waste heat of materials with the precise triggering of electrical bridge breaking based on fault diagnosis signals, the system can achieve the ability to handle everything from routine prevention to serious faults, while taking into account timeliness, reliability and energy saving. Third, the entire process is intelligently closed-loop and continuously operated, from the self-handling of blockages in negative pressure conveying to the seamless relay storage with automatic switching between dual storage tanks, ensuring the efficient, unmanned and continuous operation of the entire system.

[0045] The above description of the embodiments is only for the purpose of helping to understand the method and core ideas of the present invention. It should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. An automatic method for discharging gravel and coal, characterized in that, Includes the following steps: S1, close the second gate at the discharge port of the transfer box, open the first gate at the feed port of the transfer box, receive the stone coal discharged from the corresponding coal mill, use a dispersion device to disperse the landing point of the stone coal, and monitor the stone coal collection progress in real time through the material level sensor group. S2, based on the temperature inside the transfer box and a hybrid bridging strategy, uses a bridging unit to break the bridging phenomenon of the coal stones. The execution of the bridge-breaking unit is coordinated with the temperature and the status of the material level sensor group inside the transfer box; S3, when the level of the stone and coal material triggers the preset conveying signal, the negative pressure conveying process is executed to convey the stone and coal in the transfer box to the transfer device; The negative pressure delivery process is implemented in conjunction with a hybrid bridge-breaking strategy. S4, the transfer device receives stone coal from multiple negative pressure conveyors and continuously guides the stone coal to the main stone coal box through an automatic diversion strategy.

2. The automatic discharge method for stones and coal according to claim 1, characterized in that: The dispersion device is made of wear-resistant material and includes an umbrella-shaped structure and a baffle. The umbrella-shaped structure is located directly below the stone and coal discharge outlet, and the umbrella-shaped structure is provided with a flow guiding structure that is distributed in a circular pattern. The umbrella-shaped structure is used to initially break up the falling stones and coal. The baffles are installed on the inner wall of the transfer box, are inclined, and are distributed in layers with staggered positions. The width of the baffles decreases from top to bottom.

3. The automatic discharge method for stones and coal according to claim 2, characterized in that: The material level sensor group is installed inside the transfer box, below the baffle, and a flexible vibration isolation structure is provided between the material level sensor and the transfer box; The material level sensor group adopts a rotary paddle material level sensor; The material level sensor group includes a low-level sensor, a middle-level sensor, and a high-level sensor; The transfer box has a conical groove inside, and both the low-position sensor and the mid-position sensor are installed in the conical groove. The connection between the conical groove and the inner wall of the transfer box is rounded.

4. The automatic discharge method for stones and coal according to claim 3, characterized in that: The bridge-breaking unit includes a thermal drive component and an electric drive component. The thermal drive component is disposed on the inner wall of the transfer box, and the electric drive component is disposed on the outer wall of the transfer box. The thermal drive component and the electric drive component are evenly distributed and arranged in layers; The push rod structure of the heat-driven component is consistent with the contour of the inner wall of the transfer box; An electric drive unit is disposed below each of the low-position, mid-position, and high-position sensors.

5. The automatic discharge method for stones and coal according to claim 4, characterized in that: The hybrid bridge-breaking strategy in step S2 is as follows: when the discharge of high-temperature stone coal causes the internal temperature of the transfer box to rise, and the temperature of the shape memory alloy element in the thermal drive component is lower than the phase change threshold, the shape memory alloy element has no shrinkage tension, the built-in reset structure holds the push rod, and the thermal drive component remains in standby state. As the stones and coal gradually accumulate, when the temperature of the shape memory alloy element inside the thermal drive component reaches the phase change threshold, the shape memory alloy element undergoes a phase change, generating a contraction force that overcomes the elasticity of the reset structure, pulls the push rod back, destroys the force support points between the stones and coal, and breaks the overhead structure of the stone and coal pile. When the high-level sensor detects the level of gravel and coal, but the low-level or medium-level sensor does not detect the level of gravel and coal, the electric drive unit is instructed to perform a shock-breaking process on the transfer box.

6. The automatic discharge method for stones and coal according to claim 5, characterized in that: The process of step S3 is as follows: S31, close the first gate, and after closing, open the second gate to form a closed space between the transfer box and the negative pressure device; The execution of step S31 is based on a preset conveying signal trigger, that is, the low, middle and high level sensors all detect that the material level has been reached and maintained for 3 seconds; S32, start the negative pressure device, and create negative pressure in the negative pressure pipeline connected between the discharge port and the transfer device to transport the stone coal in the transfer box to the transfer device. S33 delivers fresh ambient air to the transfer box through the air intake structure, which cools the internal temperature of the transfer box and the heat-driven components. S34, when the temperature of the shape memory alloy element inside the thermal drive component drops below the phase transition threshold, a phase transition occurs, restoring the soft state. The reset structure releases its elastic force to hold the push rod, scraping away the residual stones and coal on the inner wall of the transfer box. S35, until the high, middle and low level sensors sequentially detect the horizontal departure of the stone and coal material level; S36, repeat S1 to S3.

7. The automatic discharge method for stones and coal according to claim 6, characterized in that: In step S32, during the operation of the negative pressure device, the pressure value of the negative pressure pipeline is monitored in real time; If an abnormal increase in negative pressure is detected, it is determined that a bridge of stones and coal has formed in the transfer box or negative pressure pipeline. The negative pressure device is instructed to stop working. Based on the horizontal position of the stone and coal material level fed back by the material level sensor group, the electric drive unit of the corresponding layer is instructed to perform a shock treatment, and then the S32 process is resumed.

8. The automatic discharge method for stones and coal according to claim 1, characterized in that: The automatic traffic splitting strategy in step S4 is as follows: S41 monitors the material level status of the main stone and coal bin in real time, and cleans the full main stone and coal bin so that at least one of the main stone and coal bins has enough storage space to hold the stone and coal. There are at least two total stone coal boxes, defined as the first total stone coal box and the second total stone coal box; S42, the transfer device receives the stone coal conveyed by multiple negative pressure conveyors and conveys it to the first main stone coal box through the diversion device; S43, when the high-level sensor in the first main stone and coal box detects that the stone and coal level has reached the target, the diversion device closes the channel connecting to the first main stone and coal box and simultaneously opens the channel connecting to the second main stone and coal box. S44, repeats S41 to S43.

9. An automatic stone and coal discharge system for implementing the automatic stone and coal discharge method described in any one of the above claims, characterized in that, It includes at least the following device: a transfer box, with a feed inlet at the top and a discharge outlet at the bottom, for collecting and transferring the stone coal directly discharged from the coal mill; The transfer box is equipped with a first gate and a second gate at its inlet and outlet, respectively, to control the flow of stones and coal. The main stone coal bin is used to receive and store stone coal discharged from multiple coal mills, providing a capacity buffer for subsequent processing; There are at least two main stone and coal bins for alternating reception of stone and coal to achieve continuous storage; The dispersion device, including an umbrella-shaped structure and baffles, is used to disperse stones and coal. The material level sensor group is installed in the transfer box and the main stone and coal box to monitor the material level of the stone and coal pile in real time; The material level sensor group inside the transfer box includes at least a high-level sensor, a middle-level sensor, and a low-level sensor distributed from top to bottom. At least one high-level sensor is installed in the main stone and coal box to detect the level of stone and coal material. The bridge-breaking unit, located in the transfer box, includes a thermal drive component and an electric drive component; The heat-driven component is installed on the inner wall of the transfer box and can automatically expand and contract in response to temperature changes in order to break bridges and clean the inner wall. The electric drive component is an impact actuator, which generates an impact force by vibrating the outer wall of the transfer box, thereby destroying the bridging structure formed by the pile of stones and coal. The negative pressure conveying unit, including a negative pressure device and a negative pressure pipeline, is used to suck out the gravel and coal in the transfer box and output it to the transfer device. The transfer device is used to receive the stone coal output from multiple negative pressure pipelines and output the stone coal to the main stone coal box through the diversion device; The input end of the diversion device cooperates with the output end of the transfer device to receive the stone coal output from the transfer device, and is provided with at least two output pipes, each output pipe being connected to a total stone coal box, and each pipe being equipped with an electric gate. The control unit is connected to the electric gates on the first gate, the second gate, the level sensor group, the electric drive unit, the negative pressure conveying unit, the transfer device, and the diversion device. The control unit is used to instruct the aforementioned devices to coordinate the opening, closing, and operation of the first gate, the second gate, the bridge-breaking unit, and the negative pressure conveying unit. The control unit performs bridge breaking and conveying control based on the material level sensor group signals in the transfer box, and performs diversion control based on the material level sensor signals in the main stone and coal box.

10. An automatic stone and coal discharge system according to claim 9, characterized in that: The thermal drive component includes: a drive cavity, an SMA spring, a return spring, and a push rod; The drive cavity is fixedly installed on the inner wall of the transfer box; The SMA spring and the return spring are coaxially arranged in the drive cavity, with one end of each fixedly connected to the cavity and the other end fixedly connected to the push rod. The push rod is slidably connected to the drive cavity, and the SMA spring and the return spring are both sleeved on the push rod. The extended end of the push rod is a scraper structure that matches the contour of the inner wall of the transfer box. When the temperature of the SMA spring reaches its phase change threshold due to the heat transfer from the high-temperature stones and coal in the transfer box, the SMA spring contracts, overcomes the elastic force of the reset spring, and pulls the push rod back into the drive cavity to destroy the bridging support point of the stones and coal. When the SMA spring cools down to below its phase transition threshold, it returns to a soft state, the reset spring releases its elasticity, and pushes the push rod outward, so that the scraper structure closely adheres to and scrapes the inner wall of the transfer box to remove residual stones and coal.

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