Control method for accurately adjusting blanking point of belt conveyor based on pressure detection

Abstract

The invention relates to a control method for accurately adjusting a blanking point of a belt conveyor based on pressure detection, which comprises the following steps of: step 1, firstly, installing two groups of weighing detection devices at a belt carrier roller bracket (14) in front of a downstream belt hopper, and modifying an existing carrier roller into a weighing carrier roller; the method comprises the following steps: step 1: firstly, feeding back a pressure value actually measured on site to a PLC (Programmable Logic Controller) analog quantity module through a pressure data converter to enter a program section for application, and step 3: finally, driving a proportional hydraulic valve (17) through a signal of a proportional amplifier to control a hydraulic push rod (18) and drive a movable baffle plate (19) to extend or retract until an adjusting signal stops to reach a steady state; according to the technical scheme, full-automatic accurate control over the material falling point of the belt conveyor is achieved, the problems of belt deviation and material overflowing are effectively solved, meanwhile, the labor intensity of workers is relieved, and a brand new thought and a feasible method are provided for control over the material falling point of the belt conveyor.

Description

Technical Field

[0001] The invention relates to a control method, in particular to a control method for accurately adjusting a drop point of a belt conveyor based on pressure detection, and belongs to the technical field of belt transportation. Background Art

[0002] Belt conveyors generally transport a variety of materials such as pellets, lump ore, and powder ore. During the up-and-down process of conveying materials, materials often deviate from the belt conveyor, which causes uneven distribution of belt force along both sides of the center line, resulting in serious belt deviation, wear, and spillage, affecting normal production operations.

[0003] The main reason is that the offset of the impact point of the chute during the transmission of the upper and lower processes causes the drop point to change, resulting in uneven distribution of the belt material. Therefore, only by trying to effectively control the position of the source impact point can the drop point be evenly distributed on the belt. Patent 201120159597.6 installs a serrated push rod positioning steel plate in the upstream belt dust cover opening to change the drop position, but the device is completely dependent on manual operation and does not achieve reasonable automatic adjustment. On the one hand, the accuracy of the drop point control needs to be strengthened, and on the other hand, it also increases the labor intensity of personnel. Therefore, a scientific and effective method for controlling the drop point is urgently needed to completely solve the above problems. Summary of the invention

[0004] The present invention aims at the problems existing in the prior art and provides a control method for accurately adjusting the dropping point of a belt conveyor based on pressure detection. The technical solution can effectively utilize the pressure signal transmitted by the material to realize fully automatic and precise control of the dropping point of the belt conveyor material, effectively alleviate the problems of belt deviation and material overflow, and reduce the labor intensity of personnel, thus providing a new idea and feasible method for controlling the dropping point of the belt conveyor.

[0005] In order to achieve the above object, the technical solution of the present invention is as follows: a control method for accurately adjusting the drop point of a belt conveyor based on pressure detection, characterized in that the method comprises the following steps:

[0006] Step 1: First, as shown in the figure above, install two sets of weighing detection devices 1 and 2 at the belt roller bracket (14) in front of the downstream belt hopper, and use the existing rollers to convert into weighing rollers. Install two sets of special pressure sensors on the roller brackets on both sides of the belt in the weighing area 4 and 5 to measure the pressure value of the material on both sides of the belt. When the material is scattered from the lower hopper onto the belt and passes through the 1 and 2 weighing roller areas, the pressure sensors 4 and 5 on the left and right sides measure the pressure feedback value and read the left and right pressure data within a certain area;

[0007] Step 2: Secondly, as shown in the figure above, the pressure value measured on site is fed back to the PLC analog module through the pressure data converter and enters the program segment application. The pressure deviation value is set through the operation and comparator function block. If it exceeds the range, the given adjustment signal is output to the proportional valve amplifier board as the feedback control amount of the hydraulic proportional valve on site. The left pressure value 1 in the module is used as the input signal of one end of the adder and subtractor 4, and at the same time as the input signal of one end of the left pressure comparator 7. The right pressure value 2 is output through the reverser 3 as the input signal of the other end of the adder and subtractor 4, and at the same time as the input signal of one end of the right pressure comparator 8. If there is a deviation between the pressure values ​​on both sides at this time, the adder and subtractor 4 outputs a positive or negative value to enter the internal judgment of the differential pressure comparator 6, and outputs a digital signal of 0 or 1 (0 is no deviation, 1 is deviation). The other input end of the left and right pressure values ​​mentioned above is respectively compared with the left and right pressure setting values ​​to the pressure comparator 7 or 8, and also outputs a digital signal of 0 or 1 (0 is not out of tolerance, 1 is out of tolerance). The digital signal output by the pressure deviation comparator 6 is respectively determined by the pressure excess digital signal on the left and right sides through the AND gate device 9 or 10 to output 0 or 1 (0 for blocking, 1 for unblocking). If the left side is unblocked, the given regulator output 11 sends a direction adjustment signal to the proportional amplifier 13. If the right side is unblocked, the given regulator output 12 sends a reverse direction adjustment signal to the proportional amplifier 13 until the AND gate device output is zero blocking, and the proportional amplifier valve core returns to the original position to stop the adjustment signal;

[0008] Step 3: Finally, as shown in the figure above, the proportional amplifier signal drives the proportional hydraulic valve 1 to control the hydraulic push rod 2 and drive the movable baffle 3 to extend or retract until the adjustment signal stops and reaches a steady state. Through the judgment of positive and negative polarity, the given command is controlled by the amplifier board pressure flow conversion to provide two adjustable control voltages U1 and U2 to the positive and negative poles of the proportional valve L to realize the bidirectional drive of the valve core. In this way, the speed of the extension and retraction of the hydraulic push rod can be adjusted, and the position of the drop point can be accurately adjusted.

[0009] Compared with the prior art, the present invention has the following advantages. First, the technical solution uses two adjacent groups of rollers on the downstream belt frame as weighing rollers, and measures the gravity of the material through the pressure sensor connected to the weighing brackets on both sides of the belt. The weight of the material is transmitted to the pressure sensors on both sides of the belt through the roller and the scale lever system. In addition to being related to the lever system, the magnitude of the force is also affected by the load on the roller, which is actually the instantaneous material weight p(t) on a section of the belt with a length of L. The pressure q(t) can be obtained as follows:

[0010] q(t)=p(t) / L

[0011] Among them, p(t) reflects the weight of an area rather than the weight of a certain point, and the reliability of data measurement is higher.

[0012] Secondly, the on-site weighing module measures the pressure values ​​on both sides of the belt and sends them to the PLC analog module through the transmitter. The program reads the pressure difference into the comparison module and outputs a pressure difference as the feedback of the proportional hydraulic control valve. When the belt drop point is offset and exceeds the pressure difference range, the proportional valve starts to control the hydraulic push rod for adjustment. As the pressure difference feedback decreases to the normal range, the proportional valve is blocked and the hydraulic push rod stops adjusting. At this time, the movable baffle is maintained at a relatively stable adjustment angle.

[0013] Finally, by comparing the measured data of the pressure sensor, the positive and negative directions of the pressure on both sides can be distinguished, and the extension and retraction of the hydraulic push rod can be controlled to achieve precise positioning. At the same time, the PLC program is used to control the proportional valve to achieve stepless speed regulation of the hydraulic push rod.

[0014] The present invention detects the pressure of the material on the belt conveyor through the detection unit, uses the control unit to feedback and adjust the pressure deviation, and arranges the drive unit to adjust the speed of the hydraulic push rod telescopic stroke, so as to accurately adjust the position of the drop point. This control method can automatically control the drop point of the belt conveyor material, effectively preventing the belt from running off and the material from overflowing. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a schematic diagram of the control flow of the present invention;

[0016] Figure 2 Working diagram for precise control of belt conveyor drop point;

[0017] Figure 3 , Figure 4 Installing distribution diagrams for detection units;

[0018] Figure 5 It is a logic diagram of the control unit;

[0019] Figure 6 Drive unit control diagram.

[0020] In the figure: 1 is the first weighing roller, 2 is the second weighing roller, 3 is the reverse sign device, 4 is the addition and subtraction operator, 5 is the absolute value, 6 is the differential pressure comparator, 7 is the left pressure comparator, 8 is the right pressure comparator, 9 is the left AND gate, 10 is the right AND gate, 11 is the left unsealing given regulator output, 12 is the right unsealing given regulator output, 13 is the proportional amplifier, 14, the weighing bracket, 15, the left pressure sensor, 16, the right pressure sensor, 17 is the proportional hydraulic valve, and 18 is the hydraulic push rod. DETAILED DESCRIPTION

[0021] In order to deepen the understanding of the present invention, the present embodiment is described in detail below with reference to the accompanying drawings.

[0022] Example 1: See Figure 1 A control method for accurately adjusting the drop point of a belt conveyor based on pressure detection. The invention measures a pressure signal transmitted by a material in a belt weighing area, feeds it back to a PLC program for calculation and comparison, and uses a variety of functional modules to output a control proportional valve to drive a hydraulic push rod to adjust a movable baffle, thereby accurately controlling the drop point position, and can effectively prevent the belt from running off and material overflow. The method comprises the following steps: Figure 1-Figure 4 :

[0023] Step 1: First, see Figure 3 , Figure 4 , install the first weighing roller 1 and the second weighing roller 2 at the belt roller bracket 3 in front of the downstream belt hopper, and use the existing rollers to convert into weighing rollers. Install two sets of special pressure sensors on the roller brackets on both sides of the belt in the weighing area, namely the left pressure sensor 15 and the right pressure sensor 16, to measure the pressure value of the material on both sides of the belt. When the material falls from the lower hopper onto the belt and passes through the weighing roller area, the pressure sensors on the left and right sides measure the pressure feedback value and read the left and right pressure data within a certain area,

[0024] Step 2: Secondly, if Figure 5 As shown, the pressure value measured on site is fed back to the PLC analog module through the pressure data converter and enters the program segment application. The pressure deviation value is set through the operation and comparator function block. If it exceeds the range, the given adjustment signal is output to the proportional valve amplifier board as the feedback control amount of the on-site hydraulic proportional valve. The left pressure value in the module is used as the input signal of one end of the adder and subtractor 4, and at the same time as the input signal of one end of the left pressure comparator 7. The right pressure value 2 is output through the reverser 3 as the input signal of the other end of the adder and subtractor 4, and at the same time as the input signal of one end of the right pressure comparator 8. If there is a deviation between the pressure values ​​on both sides at this time, the adder and subtractor 4 outputs a positive or negative value to enter the internal judgment of the differential pressure comparator 6, and outputs a digital signal of 0 or 1 (0 is no deviation, 1 is deviation). The other input end of the left and right pressure values ​​mentioned above is respectively compared with the left and right pressure setting values ​​to the pressure comparator 7 or 8, and also outputs a digital signal of 0 or 1 (0 is not out of tolerance, 1 is out of tolerance). The digital signal output by the pressure deviation comparator 6 is respectively determined by the pressure excess digital signal on the left and right sides through the AND gate device 9 or 10 to output 0 or 1 (0 is blocked, 1 is unblocked). If the left side is unblocked, the given regulator output 11 sends a direction adjustment signal to the proportional amplifier 13. If the right side is unblocked, the given regulator output 12 sends a reverse direction adjustment signal to the proportional amplifier 13 until the AND gate device output is zero blocked, and the proportional amplifier valve core returns to the original position to stop the adjustment signal.

[0025] Step 3: Finally, as shown in the figure above, the proportional amplifier signal drives the proportional hydraulic valve 16 to control the hydraulic push rod 17 and drive the movable baffle 3 to extend or retract until the adjustment signal stops and reaches a steady state. Through the judgment of positive and negative polarity, the given instruction is controlled by the amplifier plate pressure flow conversion to provide two adjustable control voltages U1 and U2 to the positive and negative poles of the proportional valve L to realize the bidirectional drive of the valve core. In this way, the speed of the extension and retraction of the hydraulic push rod can be adjusted, and the position of the drop point can be accurately adjusted.

[0026] It should be noted that the above embodiments are not intended to limit the protection scope of the present invention, and equivalent changes or substitutions made on the basis of the above technical solutions all fall within the protection scope of the claims of the present invention.

Claims

1. A control method for accurately adjusting the drop point of a belt conveyor based on pressure detection, characterized in that: The method comprises the following steps: Step 1: First, two sets of weighing detection devices are installed at the belt roller bracket (14) in front of the downstream belt hopper, and the existing rollers are converted into weighing rollers; Step 2: Secondly, the pressure value measured on site is fed back to the PLC analog module through the pressure data converter and enters the program segment application. Step 3: Finally, the proportional amplifier signal drives the proportional hydraulic valve (17) to control the hydraulic push rod (18) and drive the movable baffle (19) to extend or retract until the adjustment signal stops and reaches a steady state.

2. The control method for accurately adjusting the drop point of a belt conveyor based on pressure detection according to claim 1 is characterized in that: Step 1 is as follows: two sets of special pressure sensors, namely, a left pressure sensor (15) and a right pressure sensor (16), are installed on the roller brackets on both sides of the belt in the weighing area to measure the pressure value of the material on both sides of the belt. When the material is scattered from the lower hopper onto the belt and passes through the weighing roller area, the pressure sensors on the left and right sides measure the pressure feedback value and read the left and right pressure data within a certain area.

3. The control method for accurately adjusting the drop point of a belt conveyor based on pressure detection according to claim 2 is characterized in that: Step 2 is as follows: the pressure deviation value is set through the operation and comparator function block. If it exceeds the range, a given adjustment signal is output to the proportional valve amplifier board as the feedback control quantity of the on-site hydraulic proportional valve. The left pressure value in the module is used as the input signal of one end of the addition and subtraction operator (4), and at the same time as the input signal of one end of the left pressure comparator (7). The right pressure value is output through the reverser (3) as the input signal of the other end of the addition and subtraction operator (4), and at the same time as the input signal of one end of the right pressure comparator (8). If there is a deviation between the pressure values ​​on both sides at this time, the addition and subtraction operator (4) outputs a positive or negative value to enter the internal judgment of the differential pressure comparator (6), and outputs a digital signal of 0 or 1 (0 means no deviation, 1 means deviation). The other input ends of the left and right pressure values ​​are respectively connected to the pressure comparator (7) (8) ends, and after being compared with the left and right pressure setting values, a digital signal of 0 or 1 (0 means no deviation, 1 means deviation) is also output. The digital signal output by the pressure deviation comparator (6) is respectively determined by the pressure deviation digital signal on the left and right sides through the AND gate (9) or (10) to be 0 or 1 (0 means blocking, 1 means unblocking). If the left side is unblocked, the given regulator output (11) sends a direction adjustment signal to the proportional amplifier (13). If the right side is unblocked, the given regulator output (12) sends a reverse direction adjustment signal to the proportional amplifier (13), until the AND gate output is zero blocking, and the proportional amplifier valve core returns to the original position to stop the adjustment signal.

4. The control method for accurately adjusting the drop point of a belt conveyor based on pressure detection according to claim 3 is characterized in that: The specific steps in step 3 are as follows: by judging the positive and negative polarities, the given command is controlled by the amplifier plate pressure-flow conversion to provide two adjustable control voltages U1 and U2 to the positive and negative electrodes of the proportional valve L, realizing the bidirectional drive of the valve core, thereby adjusting the speed of the extension and retraction stroke of the hydraulic push rod and accurately adjusting the position of the drop point.

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