Non-contact stall slip alarm protection device for belt conveyor

Abstract

The utility model relates to a stall slip alarm protection device for a non-contact belt conveyor. In order to overcome the defects in the prior art, the stall slip alarm protection device for the non-contact belt conveyor comprises a PLC, a roller speed measuring device and a belt speed measuring device, the roller speed measuring device comprises a fixing frame, a proximity switch, a belt conveyor sudden stop circuit and an alarm device, the fixing frame is arranged on one side of the end of a matched roller and provided with a through hole, and the belt speed measuring device is arranged on the belt conveyor sudden stop circuit. A protruding ring is arranged on the front portion of the proximity switch, external threads are arranged on the rear portion of the proximity switch, the proximity switch is arranged in the through hole in a penetrating mode, a spiral spring is further sleeved on the proximity switch between the protruding ring and the fixing frame, two ends of the spiral spring abut against the protruding ring and the fixing frame respectively, and an adjusting nut is screwed on the external threads on the outer side of the fixing frame. N radial rods which are uniformly distributed are arranged at the end part of the matched roller, and a signal line is arranged at the rear part of the proximity switch and is connected with a pull rope or a pull rod. The speed measuring device is short in speed measuring period, can conveniently detect whether faults exist or not, and is suitable for being used in cooperation with the coal mine belt conveyor.

Description

Technical Field

[0001] This utility model relates to a non-contact belt conveyor stall and slippage alarm protection device. Background Technology

[0002] In underground coal mining, belt conveyors are commonly used to transport coal from underground to the surface. A belt conveyor consists of a head drum, a tail drum, and a belt between them. Typically, the head drum is on top and the tail drum is on the bottom. The head drum is driven by a motor and is the active drum, while the tail drum rotates under the belt and is the driven drum. During normal operation, the belt should not slip with the head drum or tail drum, and all three should move at the same speed. When the drum bearings are damaged, increasing resistance, or when the belt slips with the drum, the belt speed will match the drum speed, leading to increased resistance, localized overheating, and severe wear.

[0003] Chinese invention patent CN104030004A, published on September 10, 2014, discloses a method and device for detecting belt slippage in a belt conveyor. The device includes a detection switch, an intermediate relay, a time relay, and an alarm. The detection switch is powered by a switching power supply. An intermediate relay is connected in each group of detection switch circuits. A time relay is connected in the control circuit of each intermediate relay. The control switches of the time relays are connected in parallel and connected to the control circuit of a time delay relay. The control output signal of the time delay relay is connected to the alarm or the belt conveyor power-off control circuit.

[0004] The method steps are as follows: 1) Fix detection switches and stops on the belt conveyor rollers and supports; 2) Set a time period t with each revolution of the drive roller as a cycle; 3) Monitor the output signals of the two sets of detection switches in real time. If no output signal is detected from the detection switches within the time period t, it is determined that the belt is slipping.

[0005] This invention can be used to detect whether there is slippage between the roller and the belt. However, the device contains multiple sets of electrical components such as relays, making it complex in structure. It is also unable to check whether the device itself is faulty or detect the running speed of the belt itself.

[0006] Chinese utility model patent CN208631523U, authorized on March 22, 2019, discloses an anti-belt stall protection device, including a long roller installed between the upper and lower belts of a conveyor belt. The length of the long roller is greater than the width of the belt. A rectangular belt is installed at one end of the long roller, and the other end of the rectangular belt is connected to a speed measuring wheel of a slip switch. The slip switch is mounted on a bracket.

[0007] Above, the slip switch is connected to the PLC system. The long drum and speed measuring device of this device increase the axial length of the drum, making it unsuitable for installation in narrow underground roadways, and it also makes it impossible to check whether the device itself is faulty.

[0008] Chinese Utility Model Patent CN213504564U, authorized on June 22, 2021, discloses a monitoring device for detecting the speed of a belt conveyor, comprising a motor, a belt, a drive roller, a frame, and a redirecting roller; the motor is connected to the drive roller; the belt is mounted on the drive roller and the redirecting roller; the drive roller and the redirecting roller are mounted on the frame; a belt speed detection section, a roller speed detection section, and a PLC are added; the roller speed detection section is mounted on the frame and the redirecting roller; the belt speed detection section includes a rotary speed sensor and a connecting frame; the connecting frame is mounted on a support, and the rotary speed sensor is also mounted on the connecting frame; the rotary speed sensor is located between the belts, and the roller on the rotary speed sensor is in close contact with the belt; the signal output terminals of the rotary speed sensor and the proximity switch are both connected to the PLC; the signal output terminal of the PLC is connected to the control terminal of the motor.

[0009] The device includes a connecting shaft, a connecting rod, a trigger block, and a proximity switch. The proximity switch is triggered by the trigger block to sense the speed of the redirecting roller (i.e., the driven roller). Its speed measurement cycle is long, and it is impossible to check whether there is a fault in the device itself. Summary of the Invention

[0010] The technical problem to be solved by this utility model is how to overcome the above-mentioned defects of the prior art and provide a non-contact belt conveyor stall and slippage alarm protection device with a short speed measurement cycle and easy detection of whether there is a fault.

[0011] To solve the above-mentioned technical problems, this non-contact belt conveyor stall and slippage alarm protection device includes a PLC, a roller speed measuring device, and a belt speed measuring device. The roller speed measuring device and the belt speed measuring device are respectively connected to the signal input terminal of the PLC. The device is characterized in that: the roller speed measuring device includes a fixed frame, a proximity switch, a belt conveyor emergency stop circuit, and an alarm device. The belt conveyor emergency stop circuit and the alarm device are respectively connected to the signal output terminal of the PLC and controlled by the PLC. The fixed frame is located on one side of the end of the roller, and the fixed frame has a through hole. The proximity switch has a protruding ring at the front and an external thread at the rear, and the proximity switch passes through the through hole. Inside the hole, a helical spring is fitted on the proximity switch between the protruding ring and the fixed frame. The two ends of the helical spring abut against the protruding ring and the fixed frame respectively. An adjusting nut is screwed onto the external thread on the outside of the fixed frame. The end of the matching roller is also provided with N radial rods evenly distributed around the axis of the matching roller. A signal line is provided at the rear of the proximity switch and connected to a pull rope or pull rod. The signal line is connected to the signal input terminal of the PLC. The alarm device is connected to the signal output terminal of the PLC. The proximity switch is triggered once every time the front end of the proximity switch passes a radial rod. The proximity switch sends the signal it senses to the PLC, where N is a positive integer and 3≤N≤9.

[0012] Before use, tighten or loosen the adjusting nut to adjust the position of the front end of the proximity switch so that the proximity switch can be triggered only by the radial rod, and then it can be used.

[0013] The PLC calculates the linear velocity of the outer edge of the belt conveyor by calculating the time difference between adjacent signals sensed by the proximity switch, the circumference of the belt roller, and the number of radial rods. It then compares this linear velocity with the real-time current belt speed measured by the belt speed measuring device. If the difference between the two speeds exceeds a predetermined value Δv, an alarm is triggered. If the difference between the two speeds exceeds the predetermined value Δv and the time exceeds a predetermined time Δt, the PLC stops the operation of the belt conveyor through the emergency stop circuit.

[0014] When testing is required, the proximity switch is pulled away from the radial rod by pulling the pull rope or lever. The proximity switch will no longer sense the radial rod that it has passed. Then the pull rope or lever is released.

[0015] The speed calculated by the PLC is halved with the linear speed of the outer edge of the roller. This linear speed is compared with the real-time belt speed measured by the belt speed measuring device. If the difference between the two speeds exceeds the predetermined value Δv, an alarm is issued through the alarm device, proving that the alarm function of the stall and slippage alarm protection device for this non-contact belt conveyor is normal. Otherwise, it is judged to be abnormal.

[0016] If, within a time period exceeding the predetermined time △t, the pull rope or lever is continuously pulled and then released, and this operation is repeated multiple times, the linear speed of the outer edge of the speed-adapted roller calculated by the PLC will decrease. If the difference between this linear speed and the real-time belt speed measured by the belt speed measuring device exceeds the predetermined value △v and continues to exceed the predetermined time △t, the PLC will stop the operation of the belt conveyor through the emergency stop circuit. This proves that the emergency stop of the stall and slippage alarm protection device for this non-contact belt conveyor is normal; otherwise, it is considered abnormal.

[0017] The belt speed measuring device can be the novel belt speed detection and alarm device described in CN202421198U. With this design, the malfunction of the stall and slippage alarm protection device for this non-contact belt conveyor can be checked by periodically or irregularly pulling the rope or lever, and the speed measurement cycle is short. It features a simple structure, scientific design, and ease of use.

[0018] As an optimization, the fixing frame is made of angle steel. This design results in a simple structure and convenient processing.

[0019] This utility model is a non-contact belt conveyor stall and slippage alarm protection device with a short speed measurement cycle and easy detection of its own faults. It is suitable for use with coal mine belt conveyors. Attached Figure Description

[0020] The following description, in conjunction with the accompanying drawings, further illustrates the non-contact belt conveyor stall and slippage alarm protection device of this utility model:

[0021] Figure 1 This is a three-dimensional structural diagram of a stall and slippage alarm protection device for a non-contact belt conveyor.

[0022] In the diagram: 1 is the fixed frame, 2 is the proximity switch, 3 is the matching roller, 4 is the protruding ring, 5 is the external thread, 6 is the helical spring, 7 is the adjusting nut, 8 is the radial rod, 9 is the signal line, 10 is the pull rope, and 11 is the matching roller shaft. Detailed Implementation

[0023] Implementation method one: such as Figure 1As shown, this non-contact belt conveyor stall and slippage alarm protection device includes a PLC (not shown in the figure), a roller speed measuring device, and a belt speed measuring device. The roller speed measuring device and the belt speed measuring device are respectively connected to the signal input terminal of the PLC. The roller speed measuring device includes a fixed frame 1, a proximity switch 2, a belt conveyor emergency stop circuit (not shown in the figure), and an alarm device (not shown in the figure). The belt conveyor emergency stop circuit and the alarm device are respectively connected to the signal output terminal of the PLC and controlled by the PLC. The fixed frame 1 is located on one side of the end of the matching roller 3. The fixed frame 1 has a through hole. The proximity switch 2 has a protruding ring 4 at the front and an external thread 5 at the rear. The proximity switch 2 passes through the through hole. A helical spring 6 is fitted onto the proximity switch 2 between the ring 4 and the fixed frame 1. The two ends of the helical spring 6 abut against the protruding ring 4 and the fixed frame 1, respectively. An adjusting nut 7 is screwed onto the external thread 5 on the outer side of the fixed frame 1. The end of the matching roller 3 is also provided with N radial rods 8 evenly distributed around the axis of the matching roller 3. A signal line 9 is provided at the rear of the proximity switch 2, and a pull rope 10 is connected to it (a pull rod can also be used, omitted here). The signal line 9 is connected to the signal input terminal of the PLC, and the alarm device is connected to the signal output terminal of the PLC. Each time the front end of the proximity switch passes a radial rod 8, the proximity switch 2 is triggered once, and the proximity switch 2 sends the sensed signal to the PLC, where N is a positive integer, and 3≤N≤9. The fixed frame 1 is made of angle steel.

Claims

1. A stall-slip alarm protection device for a non-contact belt conveyor, comprising a PLC, a roller speed measuring device and a belt speed measuring device, the roller speed measuring device and the belt speed measuring device being connected to a signal input end of the PLC, characterized in that: The roller speed measuring device comprises a fixing frame, a proximity switch, a belt conveyor emergency stop circuit and an alarm device, the belt conveyor emergency stop circuit and the alarm device are connected with the signal output end of the PLC respectively and are controlled by the PLC, the fixing frame is arranged at one side of the end of the matched roller, a through hole is formed in the fixing frame, the proximity switch is arranged in the through hole, a protruding ring is arranged at the front of the proximity switch, an external thread is arranged at the rear of the proximity switch, a spiral spring is sleeved on the proximity switch between the protruding ring and the fixing frame, the two ends of the spiral spring are respectively abutted on the protruding ring and the fixing frame, an adjusting nut is screwed on the external thread at the outer side of the fixing frame, the end of the matched roller is further provided with N radial rods which are uniformly distributed around the axis of the matched roller, a signal line is arranged at the rear of the proximity switch and is connected with a pull rope or a pull rod, the signal line is connected with the signal input end of the PLC, the alarm device is connected with the signal output end of the PLC, the proximity switch is triggered once every time when the front end of the proximity switch passes one radial rod, the proximity switch sends the sensed signal to the PLC, wherein N is a positive integer and 3≤N≤9.

2. The stall-slip alarm protection device for non-contact belt conveyor according to claim 1, characterized in that: The fixing frame is made of angle steel.

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