Bulk grain receiving belt conveyor flow adjusting device and control method thereof

Abstract

The invention discloses a bulk grain receiving belt conveyor flow adjusting device and a control method thereof. The adjusting device comprises an execution unit, a detection unit and a control unit. A receiving hopper is arranged on the bulk grain receiving belt conveyor, a grain baffle is arranged at the bottom of the receiving hopper, a discharging port is formed in the grain baffle, the execution unit is arranged above the grain baffle and comprises an adjustable hole plate and an air cylinder, a round hole matched with the discharging port is formed in the adjustable hole plate, a piston rod on the air cylinder is connected with the center of the side face of the adjustable hole plate, and the air cylinder is connected with the center of the side face of the adjustable hole plate. A fixed seat of the cylinder is fixedly connected with the outer side wall of the receiving hopper; an opening matched with the adjustable pore plate is formed in the side edge of the receiving hopper; the control unit controls an electromagnetic reversing valve of the air cylinder. The problem that due to the fact that flow control of a bulk material receiver in a grain depot bulk grain receiving system is not stable, conveying equipment is blocked or overloaded and shut down is caused is solved.

Description

Technical Field

[0001] This invention relates to the field of bulk grain conveying technology, specifically to a flow regulation device and control method for a bulk grain receiving belt conveyor. Background Technology

[0002] Currently, bulk grain transportation in grain depots is generally carried out using belt conveyors. The belt conveyor is equipped with a receiving hopper at the end, through which the bulk grain enters the belt conveyor and is finally transported to the grain depot. The flow rate of bulk grain on the belt conveyor is generally controlled by controlling the flow rate of grain at the discharge port of the receiving hopper. In the bulk grain receiving system of the grain depot, flow control is the key to ensuring stable operation of the equipment and preventing blockage and overload. The most common bulk grain flow rate adjustment methods and their problems are: (1) Manual observation and mechanical gate adjustment: Relies on operator experience, response is seriously delayed, and precise control cannot be achieved, which can easily lead to equipment overload or low efficiency. (2) Automatic control based on weighing sensors or frequency conversion speed regulation: Such solutions are expensive, and the sensors are easily interfered with in harsh working conditions with dust, resulting in inaccurate measurements and insufficient reliability.

[0003] Therefore, there is an urgent need for an automated flow control solution that is low-cost, highly resistant to interference, and has a rapid response. Summary of the Invention

[0004] In view of this, the purpose of this invention is to address the shortcomings of the prior art by providing a flow regulation device and control method for a bulk grain receiving belt conveyor, which solves the problem of unstable flow control of the bulk material receiving machine in the bulk grain receiving system of the grain depot, which leads to blockage or overload shutdown of the conveying equipment.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: A flow rate regulating device for a bulk grain receiving conveyor includes an execution unit, a detection unit, and a control unit. The bulk grain receiving conveyor is equipped with a receiving hopper, and a grain baffle plate is installed at the bottom of the hopper. A discharge port is provided on the grain baffle plate. The execution unit is located above the grain baffle plate and includes an adjustable perforated plate and a cylinder. The adjustable perforated plate has a circular hole matching the discharge port. The piston rod on the cylinder is connected to the center of the side of the adjustable perforated plate. The fixed seat of the cylinder is fixedly connected to the outer wall of the receiving hopper. An opening matching the adjustable perforated plate is provided on the side of the receiving hopper. The control unit is connected to the solenoid valve of the cylinder.

[0006] Furthermore, the detection unit is a current sensor, and the control unit is equipped with an analog input module and a digital output module. The analog input module can receive the current signal from the current sensor, and the digital output module can control the solenoid directional valve of the cylinder.

[0007] Furthermore, the current sensor is connected in series in the motor power supply circuit of the bulk grain receiving conveyor belt, and can receive the motor's operating current. The signal output terminal of the current sensor is connected to the analog input module of the control unit through a shielded cable.

[0008] Furthermore, linear slide rails are provided on both sides of the grain retaining plate, and guide grooves matching the linear slide rails are provided on the lower end surfaces of both sides of the adjustable perforated plate.

[0009] Furthermore, the linear guide rail is a highly dustproof linear guide rail.

[0010] A method for controlling a flow regulating device includes the following steps: (1) Flow limiting adjustment process First-level regulation: When the current sensor detects that the motor current exceeds the preset warning threshold for a period of time t1, the control unit determines that the flow is too large and immediately outputs a signal to control the electromagnetic reversing valve of the cylinder (4) to be energized. The piston rod of the cylinder (4) extends out of the first stroke. The distance of the first stroke is equal to the radius of the material receiving hopper discharge port. The overlapping area between the round hole on the adjustable orifice plate and the discharge port is halved, and the effective flow area is reduced by 50%, thus achieving initial flow restriction. Secondary adjustment: After primary adjustment, if the current sensor detects that the motor current still exceeds the overload threshold for a period of time t2, the control unit determines that the current limit is insufficient and drives the cylinder to extend the second stroke. The second stroke distance is equal to the radius of the material receiving hopper discharge port. The circular hole and the discharge port are completely offset, and the discharge port is blocked, realizing emergency material cut-off and avoiding equipment overload. (2) Gradual recovery process Half-open recovery: When the current sensor detects that the motor current has dropped and stabilized for a period of time (t3) below the overload threshold, the control unit starts the first delay timer with a delay time of 5-30 seconds. After the delay ends, the control cylinder retracts in the reverse direction to the second stage of the stroke, and the discharge port returns to the half-open state, gradually increasing the flow rate. Full Open Recovery: In the half-open state, if the current sensor detects that the motor current is stable for a period of time and t4 is lower than the warning threshold, the control unit starts the second delay timer with a delay time of 5-30 seconds. After the delay ends, the piston rod of the drive cylinder retracts to the initial zero position, the round hole is completely aligned with the feed port, and the system returns to the full open state, restoring the maximum flow rate.

[0011] Furthermore, t1 is 25-35s, t2 is 8-15s, t3 is 10-15s, and t4 is 25-35s.

[0012] Furthermore, the warning threshold is 80%-90% of the motor's rated current, and the overload threshold is 90%-100% of the motor's rated current.

[0013] A method for modifying a flow regulating device includes the following steps: 1) An adjustable perforated plate is installed on the upper surface of the grain retaining plate, and an opening is installed on the side of the receiving hopper at the corresponding position of the adjustable perforated plate; 2) Install a cylinder on the outer wall of the receiving hopper. The piston rod on the cylinder passes through the side wall of the receiving hopper and is connected to the center of the side of the adjustable orifice plate. A solenoid directional valve is connected to the cylinder. 3) Install the control unit and connect a current sensor in series in the motor power supply circuit of the bulk grain receiving conveyor. The signal output terminal of the current sensor is connected to the analog input module in the control unit through a shielded cable, and the digital output module is connected to the solenoid directional valve.

[0014] The beneficial effects of this invention are: 1. This invention discloses a flow regulation device for a bulk grain receiving conveyor belt, which directly uses the current feedback on the motor of the bulk grain receiving conveyor belt as the direct control basis: by collecting the current signal of the downstream bulk grain receiving conveyor belt motor in real time, the material load status is directly characterized, thereby adjusting the flow of bulk grain. Compared with traditional flow or weight sensor links, it has the advantages of direct response, high measurement accuracy, strong anti-environmental interference ability, and high stability.

[0015] 2. Cylinder-Adjustable Orifice Plate Quick Adjustment Mechanism: An adjustable orifice plate is slidably connected above the grain baffle plate of the receiving hopper. The adjustable orifice plate is provided with round holes that match the size and position of the discharge port. The actuator uses a cylinder to directly drive the movement of the adjustable orifice plate, realizing three positions of the discharge port: fully open, half open, and fully closed. It can accurately control the flow rate of bulk grain, and the cylinder has a short stroke and high stability.

[0016] 3. This application is also suitable for the modification of the receiving hopper on the existing bulk grain receiving belt conveyor. As long as there is a stroke adjustment space at the bottom of the receiving hopper with the diameter of the discharge port, the flow regulation device of this application can be modified. The modification process is simple, the construction cost is low, and it is convenient for automation and precise control.

[0017] 4. The device of this application is not only simple in structure and dust resistant, but more importantly, it minimizes the cylinder stroke, thereby ensuring the rapid adjustment of the opening and the fast system response.

[0018] In addition, the entire control unit room is based on a closed-loop control logic of current threshold: the real-time current signal is compared with a preset threshold, and the difference is used by the controller to dynamically adjust the cylinder action, forming a closed-loop negative feedback system, thereby realizing automatic, accurate and stable control of material flow. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of the execution unit of the present invention; Figure 2 for Figure 1A schematic diagram of a partially open execution unit; Figure 3 This is the control principle diagram of the control unit; Figure 4 Electrical schematic diagram of the control unit; Figure 5 This is a control principle diagram of a cylinder.

[0020] In the diagram: 1-feeding hopper, 2-grain baffle plate, 3-adjustable perforated plate, 4-cylinder, 5-bulk grain receiving belt conveyor, 6-discharge port, 7-round hole, 8-opening, 9-linear slide rail. Detailed Implementation

[0021] The present invention will be further described below with reference to the accompanying drawings and embodiments. Example 1

[0022] This invention provides an automatic flow regulation device for a bulk grain receiving conveyor belt based on current feedback. See [link to relevant documentation]. Figure 1-3 The bulk grain receiving conveyor belt 5 has a receiving hopper 1, through which bulk grain enters and is conveyed forward. A grain baffle 2 is installed at the bottom of the receiving hopper 1, with multiple discharge ports 6 evenly distributed on the baffle 2. An execution unit is located above the baffle 2, including an adjustable perforated plate 3 and a cylinder 4. The adjustable perforated plate 3 is slidably connected to the baffle 2, i.e., linear slide rails 9 are provided on both sides of the baffle 2. In this embodiment, the linear slide rails 9 are high dustproof linear slide rails. Guide grooves matching the linear slide rails 9 are provided on the lower edges of both sides of the adjustable perforated plate 3, so that the adjustable perforated plate 3 can move along the baffle 2 under external force. The distance between the lower surface of the adjustable perforated plate 3 and the upper surface of the baffle 2 can be adjusted. In this embodiment, the lower surface of the adjustable perforated plate 3 contacts and can slide relative to the upper surface of the baffle 2.

[0023] The thickness of the adjustable orifice plate 3 is 8~12mm, and in this embodiment it is 10mm. The adjustable orifice plate 3 is provided with a round hole 7 that matches the discharge port 6. The cylinder 4 is a double-acting cylinder. The piston rod of the cylinder 4 passes through one end of the receiving hopper 1 and is connected to the center of the side of the adjustable orifice plate 3 through a coupling. The fixed seat of the cylinder 4 is fixedly connected to the outer wall of the receiving hopper 1. The side of the receiving hopper 1 is provided with an opening 8 that matches the adjustable hole 3. Therefore, the cylinder 4 can control the adjustable orifice plate 3 to move on the upper surface of the grain retaining plate 2.

[0024] The opening 8 on the side of the receiving hopper 1 can be on one side, such as the right side, or both sides. In this embodiment, the receiving hopper 1 has openings 8 on both sides. In addition, in actual operation, the left side of the adjustable orifice plate 3 can extend to the left of the opening 8 by a distance approximately equal to the diameter of the discharge port 6. In this way, when the adjustable orifice plate 3 moves to the right to its maximum stroke, the left edge of the adjustable orifice plate 3 is always outside the receiving hopper 1. This can reduce the resistance of the grain when the adjustable orifice plate 3 moves back and forth, making the movement smoother.

[0025] The solenoid directional valve of cylinder 4 is connected to the control unit, so the control unit can control the operation of cylinder 4. The maximum stroke of cylinder 4 is equal to the diameter of the discharge port 6 of hopper 1, that is, the maximum moving distance of adjustable orifice plate 3 is consistent with the diameter of discharge port 6, ensuring that adjustable orifice plate 3 can achieve three precise positioning: fully open, half open and fully closed.

[0026] Detection Unit: The detection unit is a current sensor, specifically a Hall effect current sensor. The current sensor is connected in series in the motor power supply circuit of the bulk grain receiving belt conveyor and can receive the motor's operating current. The signal output terminal of the current sensor is connected to the analog input module of the control unit through a shielded cable. Control unit: See its control schematic diagram. Figure 3 As shown, a PLC controller is specifically used. In this embodiment, it is a Siemens S7-1200 series. The PLC controller has a built-in analog input module and a digital output module. The analog input module is connected to the current sensor to receive the current sensor signal. The digital output module is used to control the solenoid directional valve of cylinder 4. The PLC controller has a built-in control program that supports setting parameters such as warning threshold, overload threshold, motor current duration, and delay time through a touch screen or host computer. It has data acquisition, logic judgment, and instruction execution output functions.

[0027] The control principle diagram of cylinder 4 and solenoid directional valve (solenoid valve) in this application can be found in [reference needed]. Figure 4-5 As shown, the piston inside cylinder 4 has a magnetic ring. The cylinder is equipped with a first magnetic switch, a second magnetic switch, and a third magnetic switch at the first stroke position, the second stroke position, and the initial position, respectively. When the piston of the cylinder reaches one of the positions, the magnetic switch will send a feedback signal to the PLC controller, thereby controlling the operation of the solenoid valve.

[0028] The system includes: a current sensor that collects the motor's operating current in real time and inputs it to the PLC controller; the PLC controller compares the input current with a threshold current; and if the flow rate is too high, it immediately outputs a signal to energize the left coil of the cylinder's solenoid valve. Gas then enters the rodless chamber of the cylinder through the left-side pipe and drives the piston rod of cylinder 4 to extend its first stroke (a distance equal to the radius of the hopper's discharge port). After the piston reaches the first magnetic switch position, the PLC detects the first magnetic switch signal, de-energizes the left solenoid valve, and the solenoid valve remains in the intermediate holding position. Throttling valves 1 and 2 are used to adjust the speed at which the cylinder extends or retracts.

[0029] After the first-level adjustment, if the motor current still exceeds the set overload threshold, the PLC determines that the current limiting is insufficient. The PLC outputs the drive cylinder piston rod to continue extending the second stroke (the cumulative movement distance is equal to the diameter of the hopper discharge port). The round hole 7 and the discharge port 6 are completely misaligned. After the PLC detects the second magnetic switch signal, the left solenoid valve is de-energized and the solenoid valve is in the middle holding position.

[0030] When the motor current decreases and stabilizes below the overload threshold for a set time, the PLC starts the delay timer and the right coil of the solenoid valve is energized after the delay ends. Gas enters the rod chamber of the cylinder through the right pipeline. After the gas enters the cylinder, it drives the cylinder to retract to the second stroke. That is, the first magnetic switch signal is triggered, the right coil of the solenoid valve is de-energized, and the solenoid valve is in the middle position.

[0031] When the regulating plate is half open, if the motor current remains stable within the normal load range for the set time, the PLC starts the delay timer. After the delay ends, the right coil of the solenoid valve is energized, driving the piston rod of the cylinder to retract to the initial zero position. When the cylinder stroke reaches the initial zero position, the PLC detects the third magnetic switch signal, and the right solenoid valve is de-energized, and the solenoid valve is in the middle holding position. The orifice plate through hole is fully aligned with the feed port, and the system returns to the fully open state, restoring the maximum flow rate.

[0032] The control method for the flow regulation device of the above-mentioned bulk grain receiving belt conveyor includes the following steps: (1) Flow limiting adjustment process Level 1 Adjustment (Half-Open): When the current sensor detects that the motor current exceeds the preset warning threshold (set to 85% of the motor's rated current) for 30 seconds, the PLC determines that the flow rate is too high and immediately outputs a signal to energize the cylinder solenoid directional valve. The piston rod of cylinder 4 extends its first stroke (the distance is equal to the radius of the hopper's discharge port). The overlap area between the circular hole 5 on the adjustable orifice plate 3 and the discharge port 6 is halved. See [link / reference] Figure 2 As shown, the effective circulation area is reduced by 50%, achieving initial flow restriction; Secondary adjustment (fully closed): After primary adjustment, if the motor current still exceeds the overload threshold (set to 95% of the motor's rated current) for 10 seconds, the PLC determines that the current limit is insufficient and drives the cylinder to extend the second stroke (the cumulative movement distance is equal to the diameter of the hopper discharge port). The circular hole 7 of the adjustable orifice plate 3 is completely offset from the discharge port 6, and the discharge port 6 is blocked, with only a small amount of leakage, thus achieving emergency material cut-off and avoiding equipment overload.

[0033] (2) Gradual recovery process Half-open recovery: When the motor current drops and stabilizes below the overload threshold (set to 95% of the motor's rated current) for more than 10 seconds, the PLC starts the first delay timer (delay time 20 seconds). After the delay ends, the control cylinder retracts in the reverse direction to the second stage of the stroke, the orifice plate returns to the half-open state, the effective flow area of ​​the discharge port is restored to 50%, and the flow rate is gradually increased.

[0034] Full Open Recovery: In the half-open state, if the motor current remains stable within the normal load range for 30 seconds (below the warning threshold, 85% of the motor's rated current) the PLC starts the second delay timer (delay time 20 seconds). After the delay ends, the drive cylinder retracts to the initial zero position, the orifice plate hole is fully aligned with the feed port, and the system returns to the full open state, restoring the maximum flow rate.

[0035] Through the closed-loop control of the above-mentioned graded adjustment and gradual recovery, the material flow can be quickly responded to, precisely controlled and smoothly transitioned, which can effectively prevent equipment overload and blockage, ensure conveying efficiency, and avoid material impact during the adjustment process. Example 2

[0036] A method for modifying the automatic flow regulation device of a bulk grain receiving conveyor belt includes the following steps: 1) An adjustable perforated plate 3 is provided on the upper end face of the grain retaining plate 2, and openings 8 are provided on both sides of the receiving hopper 1 at positions corresponding to the adjustable perforated plate 3; The specific operation method is as follows: linear slide rails 9 are bolted to both sides of the grain retaining plate 2, and guide grooves matching the linear slide rails 9 are fixed to the lower edge of both sides of the adjustable hole plate 3. Therefore, the adjustable hole plate 3 can move along the grain retaining plate 2 under the action of external force. 2) A cylinder 4 is fixedly connected to the outer wall of the receiving hopper 1, wherein the piston rod on the cylinder 4 passes through the side wall of the receiving hopper 1 and is connected to the center of the side of the adjustable orifice plate 3, and an electromagnetic reversing valve is connected to the cylinder 4. 3) Install the control unit and connect a current sensor in series in the motor power supply circuit of the bulk grain receiving conveyor. The signal output terminal of the current sensor is connected to the analog input module in the control unit through a shielded cable, and the digital output module is connected to the solenoid directional valve.

[0037] After the entire modification process is completed, the relevant parameters in the control unit are set. The modified receiving hopper can accurately control the grain flow. The entire modification process is simple, convenient to construct, and has low construction costs.

[0038] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Any other modifications or equivalent substitutions made by those skilled in the art to the technical solutions of the present invention, as long as they do not depart from the spirit and scope of the technical solutions of the present invention, should be covered within the scope of the claims of the present invention.

Claims

1. A bulk grain receiving belt conveyor flow regulating device, characterised in that, The utility model relates to a kind of flow control system of bulk grain receiving belt conveyor, including execution unit, detection unit and control unit;Bulk grain receiving belt conveyor (5) is provided with receiving hopper (1) on it, receiving hopper (1) bottom is provided with grain baffle (2), the grain baffle (2) is provided with discharge port (6), the execution unit is arranged above grain baffle (2), including adjustable orifice plate (3) and cylinder (4), adjustable orifice plate (3) is provided with round hole (7) matching with the discharge port (6), the piston rod of cylinder (4) is connected with the side surface center of adjustable orifice plate (3), the fixed base of cylinder (4) is fixedly connected with the outside wall of receiving hopper (1), receiving hopper (1) side is provided with the opening (8) matching with adjustable orifice plate (3);The control unit is connected with the electromagnetic reversing valve of cylinder (4).

2. The bulk grain receiving belt conveyor flow regulating device according to claim 1, characterized in that, The detection unit is current sensor, analog input module and digital output module are provided on the control unit, the current signal of current sensor can be accepted by the analog input module;The digital output module can control the electromagnetic reversing valve of cylinder (4).

3. The bulk grain receiving belt conveyor flow regulating device of claim 2, wherein, The current sensor is connected in series in the motor power supply circuit of bulk grain receiving belt conveyor (5), can receive the working current of motor, the signal output end of current sensor is connected with the analog input module of control unit by shielded cable.

4. The bulk grain receiving belt conveyor flow regulating device of claim 1 wherein, The grain baffle (2) both sides are provided with linear slide rail (9), the both sides lower end surface of adjustable orifice plate (3) is provided with guide slot matching with linear slide rail (9).

5. The bulk grain receiving belt conveyor flow regulating device of claim 1 wherein, The linear slide rail (9) is high dust linear slide rail.

6. A control method of the flow regulating device according to claim 1, characterized by, Including the following steps: (1) current-limiting regulation process Primary regulation: when current sensor detects that motor current exceeds preset early warning threshold for a period of time t1, control unit determines that flow is too large, immediately outputs signal to control the electromagnetic reversing valve of cylinder (4) to be electrified, the piston rod of cylinder (4) extends first stroke distance, the first stroke distance is equal to receiving hopper discharge port radius, the overlapping area of round hole (7) on adjustable orifice plate (3) and discharge port (6) is halved, effective flow area reduces 50%, realizes preliminary current-limiting of flow; Secondary regulation: after primary regulation, if current sensor detects that motor current still exceeds overload threshold for a period of time t2, control unit determines that current-limiting is insufficient, drives cylinder (4) to continue to extend second stroke distance, the second stroke distance is equal to receiving hopper discharge port radius, round hole (7) and discharge port (6) are completely staggered, discharge port (6) is shielded, realizes emergency material cutting, avoids equipment overload; (2) gradual recovery process Half-open recovery: when current sensor detects that motor current drops and stabilizes for a period of time t3 below overload threshold, control unit starts first delay timer, delay time is 5-30s, after delay, control cylinder (4) reversely retracts second stroke, discharge port (6) recovers half-open state, gradually improves flow; Full open recovery: in half-open state, if current sensor detects that motor current is stable for a period of time t4 below early warning threshold, control unit starts second delay timer, delay time is 5-30s, after delay, drive the piston rod of cylinder (4) retracts to initial zero position, round hole (7) and discharge port (6) are completely centered, system recovers full open state, recovers maximum flow delivery.

7. The control method according to claim 6, characterized by The t1 is 25-35s, t2 is 8-15s, t3 is 10-15s, t4 is 25-35s.

8. The control method according to claim 6, characterized by, The pre-warning threshold is 80%-90% of the rated current of the motor, and the overload threshold is 90%-100% of the rated current of the motor.

9. A retrofit method based on the flow regulating device of claim 1, characterized by, The method comprises the following steps: 1) An adjustable hole plate (3) is arranged on the upper end face of the grain blocking plate (2), and an opening (8) is arranged on the side of the receiving hopper (1) corresponding to the adjustable hole plate (3); 2) A gas cylinder (4) is installed on the outer side wall of the receiving hopper (1), the piston rod on the gas cylinder (4) is connected with the center of the side of the adjustable hole plate (3) through the side wall of the receiving hopper (1), and an electromagnetic reversing valve is connected to the gas cylinder (4); 3) A control unit is installed, a current sensor is connected in series in the motor power supply circuit of the bulk grain receiving belt conveyor, the signal output end of the current sensor is connected with an analog input module in the control unit through a shielded cable, and a digital output module is connected with the electromagnetic reversing valve.

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