Chain plate monitoring and protecting device for scraper

Abstract

The invention relates to a chain plate monitoring and protecting device for a scraper. In order to find chain breakage of the scraper conveyor earlier and give out early warning earlier, the device comprises a sensor, a programmable controller and a scraper conveyor start-stop device, and further comprises a fixing frame and two suspension rods, the tops of the two suspension rods are hinged and fixed to the fixing frame through a horizontal hinge transverse shaft, the lower ends of the two suspension rods are lower than the upper edge of a scraper of the matched scraper conveyor, and the sensor is connected with the programmable controller. A photoelectric proximity switch is arranged on the outer side of each suspension rod, the two photoelectric proximity switches form a sensor, when a scraper of the matched scraper passes through the two suspension rods, the two suspension rods can be pushed to be separated from the opposite photoelectric proximity switches, and after the programmable controller induces that induction signals of the photoelectric proximity switches are interrupted, the sensor is controlled to be switched off. And the difference value of the induction signal interruption moments of the two photoelectric proximity switches is calculated, the scraper conveyor is normally operated or emergently stopped according to the difference value, and an alarm is given out. The device is simple in structure and suitable for enterprises such as coal mines or thermal power plants.

Description

Technical Field

[0001] The present invention relates to a chain plate monitoring and protection device for a scraper conveyor. Background Art

[0002] After a chain break accident occurs in a scraper conveyor, if the machine cannot be stopped within a very short time, a serious chain coiling phenomenon will occur, bringing a large amount of workload to maintenance and restoration.

[0003] The Chinese utility model patent with the authorization announcement number CN208150376U on November 27, 2018 discloses a tilting prevention protection device for a scraper conveyor, including a sensor. The sensor is arranged above a detection hole and fixedly arranged on a fixed base. The detection hole is opened at both ends of the scraper conveyor cover plate. The sensor is used to detect the synchronization of both ends of the scraper and is electrically connected to a single-chip microcomputer control system. The sensor relies on a diffuse reflection photoelectric sensor, and one is arranged at each end of the scraper conveyor cover plate. The diffuse reflection photoelectric sensor of this utility model is easily affected by pulverized coal and dust, affecting its working stability.

[0004] The Chinese utility model with the authorization announcement number CN214326329U on October 1, 2021 discloses an upper chain break warning device for a scraper conveyor, including a scraper conveyor, a sensor, a programmable controller, and a scraper conveyor start-stop device. After the scraper conveyor starts the equipment, the start signal of the scraper conveyor device is sent into the programmable controller of the upper chain break warning device for the scraper conveyor, and the upper chain break warning device for the scraper conveyor starts to work. The sensor installed above the variable slope chute of the scraper conveyor starts to work. If the programmable controller starts the signal, but the sensor does not detect the scraper running signal, then the programmable controller logically judges that the upper chain of the scraper conveyor is broken, and immediately sends a stop signal. After the chain break, it can effectively detect and stop in time to ensure the safety of the equipment.

[0005] The integrated vibration transmitter in the upper chain break warning device for the scraper conveyor senses the vibration of the scraper running through a metal chain to judge whether there is a chain break. Only after both chains of the scraper conveyor are broken, the sensor of the upper chain break warning device for the scraper conveyor can no longer detect the scraper running signal. However, when the scraper conveyor breaks the chain, it is very rare for both side chains to break at the same time. In most cases, always one side chain breaks first. Each scraper continues to run for a period of time in a very unbalanced state under the traction of the single-side chain until the unbroken chain is also torn off. But before that, almost all the scrapers will be pulled and deformed, causing great difficulties in repairing the scraper conveyor. Summary of the Invention

[0006] The technical problem to be solved by the present invention is how to detect the chain break of the scraper conveyor earlier and issue a chain break warning earlier, and provide a chain plate monitoring and protection device for a scraper conveyor.

[0007] To solve the above technical problems, the chain plate monitoring and protection device for this scraper conveyor includes a sensor, a programmable logic controller, and a start / stop device for the scraper conveyor. The signal output end of the sensor is connected to the signal input end of the programmable logic controller, and the start / stop device for the scraper conveyor is connected to the programmable logic controller. Its characteristics are as follows: It also includes a fixed frame and two suspension rods. The fixed frame is arranged above the coal-free section coal conveying trough of the matching scraper conveyor. The tops of the two suspension rods are respectively hinged and fixed to the fixed frame through a horizontal hinge cross shaft. The axis lines of the two horizontal hinge cross shafts coincide. The lower parts of the two suspension rods are located in the coal conveying trough, and their lower ends are lower than the upper edge of the scraper of the matching scraper conveyor. A photoelectric proximity switch is respectively arranged on the outer side of each suspension rod. The two photoelectric proximity switches constitute the sensor. When the scraper of the matching scraper conveyor passes through the two suspension rods, it can push the two suspension rods away from the photoelectric proximity switches opposite to them. After the programmable logic controller senses the interruption of the induction signal of the photoelectric proximity switch, it calculates the difference between the adjacent interruption times of the induction signals of the two photoelectric proximity switches. If the absolute value of the difference < the first predetermined time, it is judged that there is no chain break and no scraper tilt, and the matching scraper conveyor is operating normally; if the first predetermined time ≤ the absolute value of the difference < the second predetermined time, it is judged that there is a scraper tilt, and a scraper tilt alarm signal is issued; if the second predetermined time ≤ the absolute value of the difference, it is judged that there is a scraper tilt and a chain break, and the programmable logic controller outputs an emergency stop signal to the start / stop device of the scraper conveyor to urgently stop the operation of the scraper conveyor, and at the same time issues a chain break alarm signal.

[0008] The programmable logic controller can select Siemens S7-200PLC. The coal-free section coal conveying trough of the matching scraper conveyor refers to the coal conveying trough between the coal outlet and the machine head or the coal conveying trough between the machine tail and the coal dropping place.

[0009] The first predetermined time can be tentatively set to 0.8 seconds, and the second predetermined time is tentatively set to 1.2 seconds, and the longest should not exceed 2 seconds. During the use process, the first predetermined time and the second predetermined time can be extended or shortened according to actual use needs. For example, during the use process, it is found that when a scraper tilt alarm signal appears, after inspection, it is found that the scraper tilt is not obvious, then the first predetermined time can be appropriately extended. If it is found that the scraper tilt is too serious and an early alarm is needed, then the first predetermined time can be appropriately shortened. Similarly, during the use process, it is found that when a chain break alarm signal appears, after inspection, it is found that neither of the two chains is broken, then the second predetermined time can be appropriately extended. If it is found that one of the chains has broken and the device still has not issued a chain break alarm signal and has not stopped urgently, then the second predetermined time needs to be appropriately shortened.

[0010] With such a design, the structure is simple and the operation is reliable.

[0011] As an optimization, the fixing frame includes columns welded to the coal retaining plates on both sides of the coal conveying trough and a cross bar welded to the tops of the two columns. The upper connecting rod and the middle connecting rod extending inwards are respectively welded to the top and the middle part of the columns. The photoelectric proximity switch is fixed on the middle connecting rod. A horizontal shaft sleeve is fixed on the upper connecting rod, and the horizontal articulated cross shaft is arranged in the horizontal shaft sleeve. With such a design, the structure is simple and firm.

[0012] As an optimization, each suspension rod is also equipped with a limit baffle. One end of the limit baffle is fixed on the horizontal shaft sleeve, and the other end extends to the upstream side of the moving direction of the scraper of the suspension rod, and limits the end point of the back swing of the suspension rod under gravity to the vertical state. With such a design, after the scraper passes, the suspension rod can return to the vertical state as soon as possible.

[0013] As an optimization, an elastic buffer sleeve is also sleeved on the contact part between the limit baffle and the suspension rod. With such a design, the collision is slowed down and the deformation of the limit baffle is prevented.

[0014] As an optimization, the suspension rod includes an upper connecting plate and a lower rubber plate, which are connected to each other, and the lower end of the lower rubber plate contacts the passing scraper. With such a design, the collision spark between the lower end of the suspension rod and the passing scraper is prevented, and the wear of the scraper is reduced.

[0015] As an optimization, an angle sensor is fixed on the top of each column. The angle sensor is connected to the signal input end of the programmable controller. One end of the adjacent horizontal articulated cross shaft is fixedly connected to the top of the suspension rod, and the other end passes through the horizontal shaft sleeve and is connected to the angle sensor. When the suspension rod is in the vertical state, the output signal of the angle sensor is a zero point signal. When the output signal of any one of the angle sensors of the programmable controller is a non-zero point signal, the angle difference of the horizontal articulated cross shaft sensed by the current two angle sensors is calculated. If the absolute value of the angle difference exceeds the predetermined angle, an emergency stop signal is output to the start-stop device of the scraper conveyor to urgently stop the operation of the scraper, and an alarm signal is sent at the same time.

[0016] Affected by the width of the suspension rod, when the passing scraper just touches the suspension rod and the suspension rod has not completely separated from the photoelectric proximity switch, the photoelectric proximity switch cannot yet sense the change in the state of the suspension rod.

[0017] After adding the angle sensor, within the measurement range of the angle sensor, as soon as the passing scraper pushes the suspension rod, the chain plate monitoring and protection device for the scraper of the present invention can sense the angle difference between the two suspension rods, so as to issue an early warning of the inclination of the scraper earlier.

[0018] The chain plate monitoring and protection device for the scraper of the present invention has a simple structure and reliable operation. When it monitors the phenomenon of the scraper being pulled obliquely or a chain break accident occurs on either side, the automatic device outputs a shutdown signal in an extremely short time, avoiding the occurrence of serious chain winding phenomena, and reducing the loss caused by the accident time to the minimum, which is suitable for enterprises such as coal mines or thermal power plants. Brief Description of the Drawings

[0019] The chain plate monitoring and protection device for the scraper conveyor of the present invention will be further described below in conjunction with the accompanying drawings: Figure 1 is a partial three-dimensional structural schematic diagram of the first implementation mode of the chain plate monitoring and protection device for the scraper conveyor in the use state; Figure 2 is when the equipped scraper conveyor is working normally Figure 1 schematic diagram of the induction signal trend of the two photoelectric proximity switches shown; Figure 3 is when the scraper of the equipped scraper conveyor is tilted or the chain is broken Figure 1 schematic diagram of the induction signal trend of the two photoelectric proximity switches shown; Figure 4 is a structural schematic diagram of the second implementation mode of the chain plate monitoring and protection device for the scraper conveyor of the present invention.

[0020] Figure 1 、 4 The direction indicated by the hollow arrow in is the moving direction of the upper scraper of the equipped scraper conveyor.

[0021] In the figure: 1 is a suspension rod, 2 is a coal conveying trough, 3 is a horizontal hinge cross shaft, 4 is a scraper, 5 is a photoelectric proximity switch, 6 is a coal baffle, 7 is a column, 8 is a cross bar, 9 is an upper connecting rod, 10 is a middle connecting rod, 11 is a horizontal bushing, 12 is a limit baffle, 13 is an elastic buffer sleeve, 101 is an upper connecting plate, 102 is a lower rubber plate, 14 is an angle sensor, 15 is a chain.

[0022] Figure 2 、 Figure 3 In, t1 and t2 are the moments when the induction signals of the left and right photoelectric proximity switches are interrupted respectively, and △t is the difference between the moment t1 and the moment t2. Specific Embodiment

[0023] Embodiment 1: As shown in Figures 1-3As shown in the figure, the chain plate monitoring and protection device for this scraper conveyor includes a sensor, a programmable controller, and a starting and stopping device for the scraper conveyor. The signal output end of the sensor is connected to the signal input end of the programmable controller, and the starting and stopping device for the scraper conveyor is connected to the programmable controller. Its characteristics are as follows: It also includes a fixed frame and two suspension rods 1. The fixed frame is arranged above the coal-free section coal conveying trough 2 of the matching scraper conveyor. The tops of the two suspension rods 1 are respectively hinged and fixed to the fixed frame through a horizontal hinge cross shaft 3. The axis lines of the two horizontal hinge cross shafts 3 coincide. The lower parts of the two suspension rods 1 are located in the coal conveying trough 2, and their lower ends are lower than the upper edge of the scraper 4 of the matching scraper conveyor. A photoelectric proximity switch 5 is respectively arranged on the outer side of each suspension rod 1. The two photoelectric proximity switches 5 constitute the sensor. When the scraper 4 of the matching scraper conveyor passes through the two suspension rods 1, it can push the two suspension rods 1 away from the photoelectric proximity switches 5 opposite to them. After the programmable controller senses the interruption of the induction signal of the photoelectric proximity switch 5, it calculates the difference △t between the adjacent interruption moments of the induction signals of the two photoelectric proximity switches 5. If the absolute value of the difference △t < the first predetermined time, it is judged that there is no chain break and no scraper tilt, and the matching scraper conveyor operates normally; if the first predetermined time ≤ the absolute value of the difference △t < the second predetermined time, it is judged that the scraper 4 is tilted, and a scraper tilt alarm signal is sent out; if the second predetermined time ≤ the absolute value of the difference △t, it is judged that the scraper 4 is tilted and a chain break occurs. The programmable controller outputs an emergency stop signal to the starting and stopping device of the scraper conveyor to urgently stop the operation of the scraper conveyor, and at the same time sends out a chain break alarm signal.

[0024] The fixed frame includes columns 7 welded to the coal retaining plates 6 on both sides of the coal conveying trough 2 and a cross bar 8 welded to the tops of the two columns 7. The upper connecting rod 9 and the middle connecting rod 10 are respectively welded inward at the top and middle of the column 7. The photoelectric proximity switch 5 is fixed on the middle connecting rod 10. A horizontal shaft sleeve 11 is fixed on the upper connecting rod 10, and the horizontal hinge cross shaft 3 is arranged in the horizontal shaft sleeve 11.

[0025] Each suspension rod 1 is also equipped with a limit baffle 12. One end of the limit baffle 12 is fixed on the horizontal shaft sleeve 11, and the other end extends to the upstream side of the moving direction of the scraper 4 of the suspension rod 1, and limits the termination point of the pendulum swing of the suspension rod 1 under gravity to the vertical state. An elastic buffer sleeve 13 is also sleeved on the contact part between the limit baffle 12 and the suspension rod 1. The suspension rod 1 includes an upper connecting plate 101 and a lower rubber plate 102, which are connected to each other, and the lower end of the lower rubber plate 102 contacts the passing scraper 4.

[0026] Embodiment 2: As Figure 4As shown, an angle sensor 14 is fixedly installed at the top of each column 7. The angle sensor 14 is connected to the signal input end of the programmable controller. One end of an adjacent horizontally hinged cross shaft 3 is fixedly connected to the top of the suspension rod 1, and the other end passes through the horizontal shaft sleeve 11 and is connected to the angle sensor 14. When the suspension rod 1 is in the vertical state, the angle sensor 14 outputs a zero-point signal. When any angle sensor 14 outputs a non-zero-point signal, the programmable controller calculates the rotation angle difference of the horizontally hinged cross shaft 3 sensed by the two current angle sensors 14. If the absolute value of the rotation angle difference exceeds a predetermined angle, an emergency stop signal is output to the start-stop device of the scraper conveyor to urgently stop the operation of the scraper conveyor, and an alarm signal is simultaneously emitted. The remaining structures are as described in Embodiment 1 and are omitted here.

Claims

1. A chain plate monitoring and protection device for a scraper conveyor, comprising a sensor, a programmable controller, and a start-stop device for the scraper conveyor. The signal output end of the sensor is connected to the signal input end of the programmable controller, and the start-stop device for the scraper conveyor is connected to the programmable controller. It is characterized in that: It also includes a fixing frame and two suspension rods. The fixing frame is arranged above the coal-free section coal conveyor trough of the equipped scraper conveyor. The tops of the two suspension rods are respectively hinged and fixed to the fixing frame through a horizontal hinge cross shaft. The axis lines of the two horizontal hinge cross shafts coincide. The lower parts of the two suspension rods are located in the coal conveyor trough, and their lower ends are lower than the upper edge of the scraper of the equipped scraper conveyor. A photoelectric proximity switch is respectively arranged on the outer side of each suspension rod. The two photoelectric proximity switches constitute the sensor. When the scraper of the equipped scraper conveyor passes through the two suspension rods, it can push the two suspension rods away from the photoelectric proximity switches opposite to them. After the programmable controller senses the interruption of the induction signal of the photoelectric proximity switch, it calculates the difference between the adjacent interruption times of the induction signals of the two photoelectric proximity switches. If the absolute value of the difference < the first predetermined time, it is judged that there is no chain break and no scraper tilt, and the equipped scraper conveyor is running normally; if the first predetermined time ≤ the absolute value of the difference < the second predetermined time, it is judged that there is a scraper tilt, and a scraper tilt alarm signal is sent out; if the second predetermined time ≤ the absolute value of the difference, it is judged that there is a scraper tilt and a chain break occurs. The programmable controller outputs an emergency stop signal to the start-stop device of the scraper conveyor to urgently stop the operation of the scraper conveyor, and at the same time sends out a chain break alarm signal.

2. The chain plate monitoring and protection device for scraper conveyor according to claim 1, characterized in that: The fixing frame includes columns welded on the coal retaining plates on both sides of the coal conveyor trough and a cross bar welded on the tops of the two columns. Upper connecting rods and middle connecting rods are respectively welded inward at the top and middle of the columns. The photoelectric proximity switch is fixed on the middle connecting rod. A horizontal shaft sleeve is fixed on the upper connecting rod, and the horizontal hinge cross shaft is arranged in the horizontal shaft sleeve.

3. The chain plate monitoring and protection device for scraper conveyor according to claim 2, characterized in that: Each suspension rod is also equipped with a limit baffle. One end of the limit baffle is fixed on the horizontal shaft sleeve, and the other end extends to the upstream side of the scraper moving direction of the suspension rod, and limits the end point of the pendulum swing of the suspension rod under gravity to the vertical state.

4. The chain plate monitoring and protection device for a scraper conveyor according to claim 3, wherein: An elastic buffer sleeve is also sleeved on the contact part between the limit baffle and the suspension rod.

5. The chain plate monitoring and protection device for a scraper conveyor according to claim 2, characterized in that: The suspension rod includes an upper connecting plate and a lower rubber plate, which are connected to each other and contact the passing scraper through the lower end of the lower rubber plate.

6. The chain plate monitoring and protection device for scraper conveyor according to any one of claims 2 to 5, characterized in that: An angle sensor is fixed on the top of each column. The angle sensor is connected to the signal input end of the programmable controller. One end of the adjacent horizontal hinge cross shaft is fixedly connected to the top of the suspension rod, and the other end passes through the horizontal shaft sleeve and is connected to the angle sensor. When the suspension rod is in the vertical state, the output signal of the angle sensor is a zero point signal. When the output signal of any one of the angle sensors of the programmable controller is a non-zero point signal, the angle difference of the horizontal hinge cross shaft sensed by the current two angle sensors is calculated. If the absolute value of the angle difference exceeds the predetermined angle, an emergency stop signal is output to the start-stop device of the scraper conveyor to urgently stop the operation of the scraper conveyor, and at the same time an alarm signal is sent out.

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