A coal conveying system and a metal object identification and sorting device thereof

Abstract

The present invention belongs to the field of foreign matter detection in coal and coal crushing, and specifically relates to a coal conveying system and a metal object identification and sorting device thereof, comprising a raw coal distributor having at least two outlets, and a conveyor belt driven by an independent motor is respectively arranged corresponding to each outlet, and the conveyor belt moves forward to convey coal backwards, and a metal detector is respectively arranged above each conveyor belt to detect metal objects in the conveyed coal. The metal object identification and sorting device also includes a control system, which is connected to each metal detector and the conveyor belt drive motor. When the control system receives a signal from the metal detector that a metal object is detected, the corresponding conveyor belt drive motor is controlled to rotate in the opposite direction to drive the conveyor belt to move in the opposite direction for a set distance, and the coal mixed with metal objects is unloaded, and at the same time, the corresponding outlet of the raw coal distributor is controlled to stop discharging coal. When a conveyor belt moves in the opposite direction to unload coal, other conveyor belts work normally, ensuring that the coal conveying system has a high coal conveying efficiency.

Description

Technical Field

[0001] The invention belongs to the field of foreign matter detection in coal and coal crushing, and in particular relates to a coal conveying system and a metal object identification and sorting device thereof. Background Art

[0002] In the process of coal mining, it is inevitable that metal objects, such as screws and anchors, will be mixed into the coal. When power plants use coal to generate electricity, they need to crush the coal first for full combustion. The coal crusher used in power plants can only crush relatively soft coal lumps and hard and brittle coal gangue, etc., and cannot crush metal objects with high hardness and certain toughness. If the metal objects mixed in the coal are not picked out, it will not only damage the gear roller of the coal crusher, but also cause the coal crusher to stop in serious cases, affecting normal power generation.

[0003] At present, the main solutions to the above problems are: set up two sets of coal conveying and coal crushing devices for the coal-fired boilers of power plants, one set is working and the other is standby. When the working set stops working because of metal mixed in the coal, the standby set is activated. The disadvantage of this measure is that the one-time investment is large. Another solution is to set up only one set of coal conveying and coal crushing devices, set up a metal detector above the conveyor belt, and pick out the metal objects in the following two ways: first, when it is found that there are metal objects mixed in the coal on the conveyor belt, the metal detector immediately starts the alarm and transmits the signal to the iron remover and other equipment to remove the metal debris. However, it is difficult for the iron remover to remove the metal debris as soon as it is found, especially for non-magnetic metal objects; second, the metal detector outputs a shutdown signal, the conveyor belt stops working, and the metal objects are picked out manually on site, and then the conveyor belt is restored. Although this method requires less investment, there will still be a short-term interruption in coal delivery, which affects the transportation efficiency and has a certain impact on the operation of the power plant boiler. Summary of the invention

[0004] The purpose of the present invention is to provide a metal object identification and sorting device to solve the technical problem of the existing technology that the on-site sorting of metal objects affects the transportation efficiency of coal. At the same time, the purpose of the present invention is also to provide a coal transportation system to solve the technical problem of the existing technology that the coal transportation system affects the transportation efficiency when sorting out metal objects mixed in coal.

[0005] To achieve the above-mentioned purpose, the technical solution of the metal object identification and sorting device in the present invention is: a metal object identification and sorting device, including a raw coal distributor, the raw coal distributor has at least two outlets, and a conveyor belt is respectively arranged corresponding to each outlet for receiving the coal output from the corresponding outlet, each conveyor belt is driven by an independent conveyor belt drive motor, the conveyor belt moves forward to transport the coal backward, and a metal detector is respectively arranged above each conveyor belt for detecting metal objects in the coal transported by the conveyor belt. The metal object identification and sorting device also includes a control system, which is connected to each metal detector and the conveyor belt drive motor. When the control system receives a signal from the metal detector that a metal object is detected, the corresponding conveyor belt drive motor is controlled to rotate in the opposite direction to drive the conveyor belt to move in the opposite direction for a set distance, thereby unloading the coal mixed with metal objects from the front end of the conveyor belt, and at the same time controlling the corresponding outlet of the raw coal distributor to stop discharging coal.

[0006] The beneficial effects of the present invention are as follows: corresponding conveyor belts are arranged at each outlet of the raw coal distributor, and each conveyor belt is driven by an independent conveyor belt drive motor, thereby forming at least two independent coal conveying branches. Since the probability of metal objects appearing on two conveyor belts at the same time is very small, therefore, in the process of a conveyor belt unloading coal mixed with metal objects through its own reverse movement, other branches where no metal objects are detected continue to convey coal backwards, ensuring that the corresponding conveying system can continuously supply materials to the coal crusher. In addition, even if metal objects appear on more than two conveyor belts at the same time, although the probability of this situation occurring is very low according to common sense, since the control system can timely control the corresponding conveyor belt to move in the opposite direction and enter the normal coal conveying state after unloading the coal, it will not have a significant impact on the coal conveying efficiency of the entire conveying system. At the same time, controlling the corresponding outlet to stop discharging coal can prevent excessive coal from being unloaded.

[0007] Furthermore, the raw coal distributor includes an augers arranged in one-to-one correspondence with each outlet, and the control system controls the corresponding outlet to stop discharging coal by controlling the augers to stop rotating.

[0008] Beneficial effect: When the corresponding conveyor belt moves in the reverse direction to unload the coal mixed with metal objects, the corresponding auger stops rotating to control the corresponding outlet to stop outputting the coal, thereby avoiding unloading too much coal and increasing the workload of the staff.

[0009] Furthermore, when the control system controls the corresponding auger to stop, it also controls at least one of the remaining augers to accelerate, so as to increase the coal conveying capacity of the auger.

[0010] Beneficial effect: The accelerated rotation of the auger can increase the coal output of the corresponding outlet to compensate for the reduced coal output of the stopped auger.

[0011] Furthermore, when the control system controls the corresponding auger to accelerate its rotation, it also controls the conveyor belt corresponding to the accelerated auger to accelerate its forward movement.

[0012] Beneficial effect: The conveyor belt corresponding to the accelerated rotation of the auger also accelerates, so that the conveying speed of the conveyor belt matches the coal output of the corresponding outlet, avoiding excessive accumulation of coal on the conveyor belt. At the same time, controlling the accelerated movement of the conveyor belt can immediately compensate for the loss of raw coal transportation caused by the reverse movement of individual conveyor belts in the metal object identification and sorting device.

[0013] Furthermore, the metal object identification and sorting device also includes a temporary storage device arranged below the front end of the conveyor belt, which is used to collect the coal unloaded by the reverse movement of the conveyor belt.

[0014] Beneficial effect: A temporary storage device is set up to collect the coal unloaded by the conveyor belt to avoid the unloaded coal being scattered on the ground and increasing the workload of the staff.

[0015] Furthermore, the temporary storage device includes a receiving hopper and a collecting bin. The receiving hopper receives the coal unloaded from the conveyor belt and guides the coal to flow into the collecting bin.

[0016] Beneficial effect: A receiving hopper is provided to guide the unloaded coal to flow to the collecting bin, ensuring that the unloaded coal can accurately enter the collecting bin.

[0017] To achieve the above-mentioned purpose, the technical scheme of the coal conveying system of the present invention is: a coal conveying system, comprising a coal crusher and a conveying device for conveying coal to the coal crusher, a metal object identification and sorting device is arranged between the conveying device and the coal crusher, the metal object identification and sorting device comprises a raw coal distributor, the raw coal distributor has at least two outlets, and a conveyor belt is arranged corresponding to each outlet for receiving the coal output from the corresponding outlet, each conveyor belt is driven by an independent conveyor belt driving motor, the conveyor belt moves forward to convey the coal backward, a metal detector is arranged above each conveyor belt for detecting metal objects in the coal conveyed by the conveyor belt, the metal object identification and sorting device also comprises a control system, which is connected to each metal detector and the conveyor belt driving motor, and when the control system receives a signal from the metal detector that a metal object is detected, the corresponding conveyor belt driving motor is controlled to rotate in the opposite direction to drive the conveyor belt to move in the opposite direction for a set distance, the coal mixed with metal objects is unloaded from the front end of the conveyor belt, and at the same time, the corresponding outlet of the raw coal distributor is controlled to stop discharging coal. The conveying device conveys the coal to the raw coal distributor of the metal object identification and sorting device, and the conveyor belt of the metal object identification and sorting device conveys the coal to the coal crusher.

[0018] The beneficial effects of the present invention are as follows: corresponding conveyor belts are arranged at each outlet of the raw coal distributor, and each conveyor belt is driven by an independent conveyor belt drive motor, thereby forming at least two independent coal conveying branches. Since the probability of metal objects appearing on two conveyor belts at the same time is very small, when a conveyor belt unloads coal mixed with metal objects through its own reverse movement, other branches where no metal objects are detected continue to convey coal backwards, ensuring that the conveying system can continuously supply materials to the coal crusher. In addition, even if metal objects appear on more than two conveyor belts at the same time, although the probability of this situation occurring is very low according to common sense, since the control system can timely control the corresponding conveyor belts to move in the opposite direction and enter the normal coal conveying state after unloading the coal, it will not have a significant impact on the coal conveying efficiency of the entire conveying system. At the same time, controlling the corresponding outlets to stop discharging coal can prevent excessive coal from being unloaded.

[0019] Furthermore, the raw coal distributor includes an augers arranged in one-to-one correspondence with each outlet, and the control system controls the corresponding outlet to stop discharging coal by controlling the augers to stop rotating.

[0020] Beneficial effect: When the corresponding conveyor belt moves in the reverse direction to unload the coal mixed with metal objects, the corresponding auger stops rotating to control the corresponding outlet to stop outputting the coal, thereby avoiding unloading too much coal and increasing the workload of the staff.

[0021] Furthermore, when the control system controls the corresponding auger to stop, it also controls at least one of the remaining augers to accelerate, so as to increase the coal conveying capacity of the auger.

[0022] Beneficial effect: The accelerated rotation of the auger can increase the coal output of the corresponding outlet to compensate for the reduced coal output of the stopped auger.

[0023] Furthermore, when the control system controls the corresponding auger to accelerate its rotation, it also controls the conveyor belt corresponding to the accelerated auger to accelerate its forward movement.

[0024] Beneficial effect: The conveyor belt corresponding to the accelerated rotation of the auger also accelerates, so that the conveying speed of the conveyor belt matches the coal output of the corresponding outlet, avoiding excessive accumulation of coal on the conveyor belt. At the same time, controlling the accelerated movement of the conveyor belt can immediately compensate for the loss of raw coal transportation caused by the reverse movement of individual conveyor belts in the metal object identification and sorting device.

[0025] Furthermore, the metal object identification and sorting device also includes a temporary storage device arranged below the front end of the conveyor belt, which is used to collect the coal unloaded by the reverse movement of the conveyor belt.

[0026] Beneficial effect: A temporary storage device is set up to collect the coal unloaded by the conveyor belt to avoid the unloaded coal being scattered on the ground and increasing the workload of the staff.

[0027] Furthermore, the temporary storage device includes a receiving hopper and a collecting bin. The receiving hopper receives the coal unloaded from the conveyor belt and guides the coal to flow into the collecting bin.

[0028] Beneficial effect: A receiving hopper is provided to guide the unloaded coal to flow to the collecting bin, ensuring that the unloaded coal can accurately enter the collecting bin. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a structural schematic diagram of the coal conveying system of the present invention;

[0030] Figure 2 for Figure 1 Schematic diagram of the structure of the metal object identification and sorting device of the medium coal transportation system;

[0031] Figure 3 for Figure 2 A schematic diagram of the structure of the distributor frame;

[0032] In the figure: 1- conveying device; 2- metal object identification and sorting device; 3- coal crusher; 4- distributor frame; 5- first auger; 6- second auger; 7- third auger; 8- first conveyor belt; 9- second conveyor belt; 10- third conveyor belt; 11- first metal detector; 12- second metal detector; 13- third metal detector; 14- auger drive motor; 15- receiving hopper; 16- collecting bin; 17- exit. DETAILED DESCRIPTION

[0033] Embodiment 1 of the coal conveying system of the present invention, as Figure 1 As shown, it includes a coal crusher 3 and a conveying device 1 for conveying coal to the coal crusher 3. In order to prevent metal objects mixed in the coal from entering the coal crusher 3 and damaging the gear roller or causing the coal crusher 3 to stop, a metal object identification and sorting device 2 is arranged between the conveying device 1 and the coal crusher 3 to identify and sort the metal objects mixed in the coal.

[0034] The structure of the metal object identification and sorting device 2 is as follows: Figure 2 As shown, it includes a raw coal distributor and three conveyor belts. The raw coal distributor includes Figure 3 The distributor frame 4 shown has an open structure at the top, which is used to receive the coal delivered by the conveying device 1. In order to achieve coal distribution, three augers are arranged in the distributor frame 4, namely the first augers 5, the second augers 6 and the third augers 7, each of which is driven by an independent augers driving motor 14. Correspondingly, the front and rear walls of the distributor frame 4 are provided with mounting holes for mounting the augers.

[0035] The rear ends of the three augers are all inserted through the mounting holes on the rear wall of the distributor frame. The coal in the distributor frame 4 is output through the three mounting holes on the rear wall of the distributor frame by the rotation of the augers. These three mounting holes constitute the three outlets 17 of the raw coal distributor. Since each augers is driven by an independent augers driving motor 14, the start and stop of each augers can be controlled separately, thereby controlling the coal output of the corresponding outlet. In this embodiment, the augers driving motor is a servo motor.

[0036] Three conveyor belts are arranged corresponding to the three outlets 17, and are used to receive and transport the coal output from the corresponding outlets 17. Each conveyor belt moves forward to transport the coal backward to the coal crusher 3. Specifically, the three conveyor belts are the first conveyor belt 8 corresponding to the first auger 5, the second conveyor belt 9 corresponding to the second auger 6, and the third conveyor belt 10 corresponding to the third auger 7. Each conveyor belt is driven by an independent conveyor belt drive motor, forming three relatively independent coal conveying branches in the metal object identification and sorting device. By controlling the rotation direction of each conveyor belt drive motor, the motion state of each conveyor belt can be controlled. In this embodiment, the conveyor belt drive motor is a servo motor.

[0037] In order to detect metal objects in the coal transported by each conveyor belt, a metal detector is provided above each conveyor belt, wherein a first metal sensor 11 is provided corresponding to the first conveyor belt 8, a second metal sensor 12 is provided corresponding to the second conveyor belt 9, and a third metal sensor 13 is provided corresponding to the third conveyor belt 10.

[0038] Furthermore, in order to timely sort out metal objects after the metal detector detects metal objects, the metal object identification and sorting device 2 is also provided with a control system. After the metal detector detects metal objects, it can feedback signals to the control system. At the same time, the control system is connected with each auger drive motor and each conveyor belt drive motor to control the rotation speed of each auger and the motion state of each conveyor belt. In this embodiment, the computer controls each auger drive motor 14 and the conveyor belt drive motor through a series of instructions.

[0039] Taking the first metal detector 11 as an example, when the first metal detector 11 detects metal objects mixed in the coal transported by the first conveyor belt 8, the first metal detector 11 feeds back a detection signal to the computer. After receiving the detection signal, the computer issues three instructions almost simultaneously: first, the conveyor belt drive motor corresponding to the first conveyor belt 8 is controlled to rotate in the reverse direction, driving the first conveyor belt 11 to move in the reverse direction for a set distance, so as to unload the coal mixed with metal objects from the front end of the first conveyor belt. The distance of the reverse movement of the first conveyor belt 11 is determined according to the distance between the first metal detector 11 and the front end of the first conveyor belt 11, so as to ensure that the coal mixed with metal objects can be unloaded after the first conveyor belt moves in the reverse direction for a set distance; second, the first auger 5 is controlled to stop rotating so as to suspend the output of coal from the corresponding outlet 17; third, the remaining auger in the raw coal distributor is controlled to increase the speed of coal transportation at an appropriately increased speed, so as to ensure the coal supply of the coal crusher 3. After the coal mixed with metal objects is unloaded, the control system controls each part to quickly resume normal operation.

[0040] In other embodiments, while the second and third augers increase their rotation speeds to increase the output of coal, the movement speeds of the second and third conveyor belts can also be increased so that the conveying speed of the conveyor belts matches the speed of coal out of the corresponding outlets. Of course, when the first conveyor belt moves in the opposite direction to unload the coal, if only increasing the movement speed of another augers and the corresponding conveyor belts can ensure the coal supply to the coal crusher, only the movement speed of one augers and the corresponding conveyor belts can be increased. Even under the premise that the stability of coal supply is not required, the movement speeds of the remaining augers and conveyor belts do not need to be increased. As for the control system, in other embodiments, each metal detector and drive motor can also be connected to a single-chip microcomputer or a PLC controller for control.

[0041] Furthermore, in order to collect the coal removed by the reverse movement of the conveyor belt, in this embodiment, the metal object identification and sorting device 2 also includes a temporary storage device, which is arranged at the lower side of the front end of the conveyor belt and is used to collect the coal removed by the reverse movement of the conveyor belt. Figure 2 As shown, the temporary storage device includes a receiving hopper 15 and a collecting bin 16, wherein the receiving hopper 15 is used to receive and guide the coal to flow to the collecting bin 16 to prevent the coal from scattering on the ground, so as to facilitate workers to pick out metal objects and then send the coal to the coal crusher 3.

[0042] It should be noted that, considering the amount of metal objects mixed in the actual raw coal, the probability of metal objects appearing on the three conveyor belts at the same time is almost zero. Therefore, when a conveyor belt needs to move in the opposite direction to unload the coal mixed with metal objects, the other conveyor belts can still continue to transport the coal, ensuring that the conveying system can maintain a stable coal transportation efficiency. In addition, the probability of metal objects appearing on two conveyor belts at the same time is also very small. Therefore, under the premise that the conveying capacity meets the requirements, in order to reduce production costs, only two conveyor belts can be set, and correspondingly, only two augers are required. Of course, four or more conveyor belts can also be set to improve the safety production coefficient and increase the conveying capacity of the coal conveying system.

[0043] Embodiment 2 of the coal conveying system of the present invention is different from Embodiment 1 in that, in Embodiment 1, an auger is provided in the raw coal distributor of the metal object identification and sorting device, and the control system controls whether the corresponding outlet outputs coal by controlling the start and stop of the auger. In this embodiment, a plurality of outlets are provided at the bottom of the distributor frame 4, and the coal is output from each outlet by its own gravity. A baffle is provided for each outlet, and each baffle is driven by an independent cylinder, which is connected to the corresponding control system. When it is detected that metal objects are mixed in the coal conveyed by a certain conveyor belt, in order to stop the corresponding outlet from discharging coal, the control system controls the corresponding cylinder to move and pushes the corresponding baffle to close the outlet.

[0044] An embodiment of the metal object identification and sorting device in the present invention comprises a raw coal distributor, a conveyor belt, a metal detector and a control system. The metal object identification and sorting device has at least two independent coal conveying branches. Specifically, the structure and working mode of the metal object identification and sorting device are the same as those of the metal object identification and sorting device in the above-mentioned coal conveying system, which will not be described in detail here.

Claims

1. A metal object identification and sorting device, characterized in that: The invention comprises a raw coal distributor having at least two outlets. A conveyor belt is provided corresponding to each outlet to receive the coal outputted from the corresponding outlet. Each conveyor belt is driven by an independent conveyor belt driving motor. The conveyor belt moves forward to transport the coal backward. A metal detector is provided above each conveyor belt to detect metal objects in the coal transported by the conveyor belt. The metal object identification and sorting device also includes a control system, which is connected to each metal detector and the conveyor belt drive motor. When the control system receives a signal from the metal detector that a metal object is detected, the control system controls the corresponding conveyor belt drive motor to rotate in the opposite direction to drive the conveyor belt to move in the opposite direction for a set distance, thereby unloading the coal mixed with metal objects from the front end of the conveyor belt, and at the same time controls the corresponding outlet of the raw coal distributor to stop discharging coal.

2. The metal object identification and sorting device according to claim 1, characterized in that: The raw coal distributor includes an augers arranged in one-to-one correspondence with each outlet, and the control system controls the corresponding outlet to stop discharging coal by controlling the augers to stop rotating.

3. The metal object identification and sorting device according to claim 2, characterized in that: When the control system controls the corresponding auger to stop, it also controls at least one of the remaining auger to accelerate, so as to increase the coal conveying capacity of the auger.

4. The metal object identification and sorting device according to claim 3, characterized in that: When the control system controls the corresponding auger to accelerate its rotation, it also controls the conveyor belt corresponding to the auger that accelerates its rotation to accelerate its forward movement.

5. The metal object identification and sorting device according to any one of claims 1 to 4, characterized in that: The metal object identification and sorting device also includes a temporary storage device arranged below the front end of the conveyor belt, which is used to collect the coal materials unloaded by the conveyor belt when it moves in the reverse direction.

6. The metal object identification and sorting device according to claim 5, characterized in that: The temporary storage device comprises a receiving hopper and a collecting bin. The receiving hopper receives the coal unloaded from the conveyor belt and guides the coal to flow into the collecting bin.

7. A coal conveying system, comprising a coal crusher and a conveying device for conveying coal to the coal crusher, characterized in that: A metal object identification and sorting device as described in any one of claims 1 to 6 is arranged between the conveying device and the coal crusher. The conveying device conveys coal to the raw coal distributor of the metal object identification and sorting device, and the conveyor belt of the metal object identification and sorting device conveys coal to the coal crusher.

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