Belt conveyor tensioner and hydraulic cylinder stroke control method

Abstract

The application relates to a stroke control method of a hydraulic cylinder of a belt conveyor tensioning device, which comprises the following steps: preparation for starting, piston rod in place, on-off valve cut-off, winch starting, on-off valve opening, belt conveyor starting, proportional relief valve pressure relief and the like. The stroke control method of the hydraulic cylinder of the belt conveyor tensioning device can not only ensure the stability of the belt conveyor in the running stage, but also enable the belt conveyor to have sufficient stroke of the tensioning cylinder to absorb the loose side in the starting stage; the tensioning cylinder also has sufficient stroke to release the tension of the belt in the belt conveyor stopping stage.

Description

TECHNICAL FIELD

[0001] The application relates to a belt conveyor tensioning device and a hydraulic cylinder stroke control method, and belongs to the technical field of conveying equipment. BACKGROUND

[0002] The D117 tubular belt conveyor of a new project of Meigang is one of two lines for supplying mixed ore to a sintering machine and is the only straight supply line for block ore and pellets for a blast furnace, and the average operation rate is more than 90%. The operation reliability directly relates to the stable and smooth operation of the blast furnace.

[0003] The belt conveyor tensioning device is a hydraulic automatic tensioning device, adopts a cylinder plus an electric hoist device mode, and mainly comprises a tensioning cylinder, a hydraulic pump station, an electric hoist device, an energy storage station, a fixed rope seat and a pulley, a connecting oil pipe, an electrical control box, a man-machine interface, a steel wire rope and a rope clamp. The hydraulic tensioning device comprises four working states: a belt conveyor preparation starting state, a belt conveyor starting completion state, a belt conveyor preparation stopping state and a belt conveyor stopping completion state. The first two states (the preparation starting state and the starting completion state) are used to maintain the stability of the belt conveyor during starting, and the last two states (the preparation stopping state and the stopping completion state) are used to maintain the stability of the belt conveyor during stopping and to reduce the belt tension in time after stopping, thereby prolonging the service life of the belt.

[0004] The belt of the D117 tubular belt conveyor is a non-steel wire belt, has a length of 4000m, a large extension rate and a large elongation after stretching, and the following problems exist during starting and stopping.

[0005] 1. During starting of the belt conveyor, a high-voltage motor is directly started, there is no frequency conversion, there is no adjustment of the hydraulic pressure, the starting time is short, the belt produces a fast loose side during starting, the hydraulic cylinder has no enough back stroke to absorb the loose side, and the belt throwing and beating phenomenon during starting of the belt conveyor is serious. If the back stroke of the cylinder is too small, the piston will hit the rear end cover of the cylinder, the cylinder is easy to be damaged, and the pressure displayed by the hydraulic system cannot reflect the real load.

[0006] 2. During stopping of the belt conveyor, the head wheel stops running, the pulling force on the upper belt disappears, the loose side generated during starting needs to be quickly rebounded, the pulling force of the cylinder rapidly rises, the piston rod quickly extends forward, if the cylinder has no enough forward stroke, the belt tension cannot be released during stopping of the belt conveyor, and even the belt tension is increased, which not only brings safety hazards, but also accelerates the aging of the belt. If the forward stroke is too small, the piston will hit the front end cover of the cylinder, the cylinder is easy to be damaged, and the pressure detected by the system cannot reflect the real load. SUMMARY

[0007] The application aims to overcome the defects of the above-mentioned technologies and provide a reliable and simple stroke control method of a hydraulic tensioning cylinder.

[0008] To solve the above technical problems, the first technical solution of the present application is: a belt conveyor tensioning device, comprising: a hydraulic cylinder, a winch, a hydraulic pump, an oil tank and an accumulator; the piston rod of the hydraulic cylinder is connected with the winch through a steel wire rope, the steel wire rope is wound on a pulley block, one end of the pulley block is fixed, and the other end is connected with a tensioning vehicle of the belt conveyor; the hydraulic pump connects the oil tank and the hydraulic cylinder through a pipeline to drive the piston rod of the hydraulic cylinder to extend or retract; a reversing valve is arranged on the pipeline connected with the hydraulic cylinder; a on-off valve is arranged on the pipeline between the reversing valve and the rod cavity of the hydraulic cylinder; a hydraulic control check valve is arranged on the pipeline between the on-off valve and the reversing valve; the pipeline between the on-off valve and the hydraulic control check valve also connects the accumulator; the accumulator is connected with the oil tank through a pipeline; an electromagnetic ball valve, a proportional overflow valve and a throttle valve are arranged in sequence on the pipeline between the accumulator and the oil tank; the pipeline between the throttle valve and the oil tank is also connected with the reversing valve; the pipeline between the throttle valve and the oil tank is also connected to the pipeline between the hydraulic pump and the reversing valve through an overflow valve; the hydraulic cylinder has a displacement sensor capable of detecting the movement distance of the piston rod; a first pressure sensor is arranged on the pipeline between the on-off valve and the hydraulic cylinder; a second pressure sensor is arranged on the pipeline between the accumulator and the electromagnetic ball valve.

[0009] To solve the above technical problems, the first technical solution of the present application is: a belt conveyor tensioning device, comprising: a hydraulic cylinder, a winch, a hydraulic pump, an oil tank and an accumulator; the piston rod of the hydraulic cylinder is connected with the winch through a steel wire rope, the steel wire rope is wound on a pulley block, one end of the pulley block is fixed, and the other end is connected with a tensioning vehicle of the belt conveyor; the hydraulic pump connects the oil tank and the hydraulic cylinder through a pipeline to drive the piston rod of the hydraulic cylinder to extend or retract; a reversing valve is arranged on the pipeline connected with the hydraulic cylinder; a on-off valve is arranged on the pipeline between the reversing valve and the rod cavity of the hydraulic cylinder; a hydraulic control check valve is arranged on the pipeline between the on-off valve and the reversing valve; the pipeline between the on-off valve and the hydraulic control check valve also connects the accumulator; the accumulator is connected with the oil tank through a pipeline; an electromagnetic ball valve, a proportional overflow valve and a throttle valve are arranged in sequence on the pipeline between the accumulator and the oil tank; the pipeline between the throttle valve and the oil tank is also connected with the reversing valve; the pipeline between the throttle valve and the oil tank is also connected to the pipeline between the hydraulic pump and the reversing valve through an overflow valve; the hydraulic cylinder has a displacement sensor capable of detecting the movement distance of the piston rod; a first pressure sensor is arranged on the pipeline between the on-off valve and the hydraulic cylinder; a second pressure sensor is arranged on the pipeline between the accumulator and the electromagnetic ball valve.

[0010] The belt conveyor starting stage control process comprises the following steps:

[0011] Step 11: the belt conveyor is ready to start;

[0012] Step 12: detect whether the position of the piston rod of the hydraulic cylinder is in the preparation start segment of the piston rod through the displacement sensor; if yes, go to the next step; if not, start the hydraulic pump, control the piston rod of the hydraulic cylinder to extend or retract through the reversing valve to the preparation start segment of the piston rod;

[0013] Step 13: the on-off valve cuts off the pipeline of the rod cavity of the hydraulic cylinder, the hydraulic cylinder is in a locked state, and the position of the piston rod of the hydraulic cylinder is fixed; the hydraulic pump charges the accumulator through the reversing valve and the hydraulic control check valve;

[0014] Step 14: Start the winch to gradually tighten the steel wire rope, and through the tensioning vehicle, the belt of the belt conveyor is tightened; when the detection value of the first pressure sensor reaches the preparation starting value, the winch stops; when the detection value of the second pressure sensor reaches the preparation starting value, the hydraulic pump stops;

[0015] Step 15: The on-off valve is opened, and the hydraulic cylinder locking is released;

[0016] Step 16: The belt conveyor is started; the hydraulic pump is started, the piston rod of the hydraulic cylinder is actively retracted through the reversing valve, the belt is tightened through the steel wire rope, and the belt conveyor stops after the detection value of the first pressure sensor reaches the preparation starting value and remains stable without fluctuation;

[0017] Step 17: The proportional relief valve is pressure released, the pressure of the accumulator is the starting completion value and remains stable, and whether the position of the piston rod of the hydraulic cylinder is in the normal running section is detected through the displacement sensor; if yes, the belt conveyor is started and starts normal operation; if no, the winch is started, the hydraulic pump is started, the piston rod of the hydraulic cylinder is controlled to run to the normal running section through the reversing valve, the winch stops, the hydraulic pump stops, and the belt conveyor enters the normal running mode;

[0018] The belt conveyor shutdown stage control process comprises the following steps:

[0019] Step 21: Before the conveying process stops, the belt conveyor is prepared to be shut down;

[0020] Step 22: The winch is started, the steel wire rope is released, the hydraulic pump is started, and the piston rod of the hydraulic cylinder is retracted to the preparation shutdown section through the reversing valve;

[0021] Step 23: The on-off valve cuts off the rod cavity pipeline of the hydraulic cylinder, and the hydraulic cylinder is in a locked state; the position of the piston rod of the hydraulic cylinder is fixed;

[0022] Step 24: The proportional relief valve is pressure released to the preparation shutdown value of the pressure of the accumulator and remains;

[0023] Step 25: The on-off valve is opened, and the hydraulic cylinder locking is released; the proportional relief valve starts to pressure release to the preparation shutdown value of the pressure of the accumulator;

[0024] Step 26: The belt conveyor is shut down;

[0025] Step 27: The proportional relief valve is pressure released to the shutdown completion value of the pressure of the accumulator;

[0026] Step 28: Whether the position of the piston rod of the hydraulic cylinder reaches the upper limit warning section is checked through the displacement sensor; if no, the belt conveyor is shut down; if yes, the winch is started to release the steel wire rope, the piston rod of the piston rod is retracted to the shutdown completion section, and the belt conveyor is shut down.

[0027] The further improvement of the above scheme is that the whole stroke of the piston rod of the hydraulic cylinder from the retraction to the limit position to the extension to the limit position is sequentially divided into five segments, which are a lower limit warning segment, a preparation shutdown segment, a normal operation segment, a preparation start segment and an upper limit warning segment, and the preparation start segment is also a shutdown completion segment.

[0028] The further improvement of the above scheme is that the preparation start value is greater than the start completion value, which is greater than the preparation shutdown value, which is greater than the shutdown completion value.

[0029] The belt conveyor tensioning device and the hydraulic cylinder stroke control method provided by the application can not only ensure the stability of the belt conveyor in the running stage, but also enable the belt conveyor to have sufficient stroke of the tensioning cylinder to absorb the loose side in the starting stage, and the tensioning cylinder also has sufficient stroke to release the tension of the belt in the stopping stage of the belt conveyor. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 is a preferred embodiment structure diagram of the application.

[0031] Figure 2 is a segmented diagram of the piston rod of the hydraulic cylinder. DETAILED DESCRIPTION EMBODIMENT

[0032] The belt conveyor tensioning device of the embodiment, like Figure 1As shown, it comprises: hydraulic cylinder 8, winch 9, hydraulic pump 1, oil tank 20 and accumulator 15; the piston rod of hydraulic cylinder 8 is connected with winch 9 through steel wire rope 10, the steel wire rope 10 is wound on the pulley block, one end of the pulley block is fixed, the other end is connected with the tensioning vehicle 11 of the belt conveyor, the tensioning vehicle 11 bears the tail wheel 12 of the belt conveyor; the hydraulic pump 1 is connected with the oil tank 20 and the hydraulic cylinder 8 through the pipeline to drive the piston rod of the hydraulic cylinder 8 to extend or retract; the hydraulic pump 1 is provided with three-position four-way electromagnetic reversing valve 4 on the pipeline connected with the hydraulic cylinder 8; the pipeline between the three-position four-way electromagnetic reversing valve 4 and the rod cavity of the hydraulic cylinder 8 is provided with on-off valve 6; the pipeline between the on-off valve 6 and the three-position four-way electromagnetic reversing valve 4 is provided with hydraulic control check valve 5; the pipeline between the on-off valve 6 and the hydraulic control check valve 5 is also connected with the accumulator 15; the accumulator 15 is connected with the oil tank 20 through the pipeline; the pipeline between the accumulator 15 and the oil tank 20 is sequentially provided with electromagnetic ball valve 17, proportional overflow valve 18 and throttle valve 19; the pipeline between the throttle valve 19 and the oil tank 20 is also connected with the three-position four-way electromagnetic reversing valve 4; the pipeline between the throttle valve 19 and the oil tank 20 is also connected to the pipeline between the hydraulic pump 1 and the three-position four-way electromagnetic reversing valve 4 through the overflow valve 3; the hydraulic cylinder 8 has displacement sensor 7 capable of detecting the moving distance of the piston rod; the first pressure sensor 14 is mounted on the pipeline between the on-off valve 6 and the hydraulic cylinder 8; the second pressure sensor 16 is mounted on the pipeline between the accumulator 15 and the electromagnetic ball valve 17.

[0033] As shown in the figure, Figure 2 The piston rod of the hydraulic cylinder 8 is divided into five sections from the retraction to the limit position to the extension to the limit position, which are lower limit warning section, preparation for shutdown section, normal operation section, preparation for start section and upper limit warning section, the preparation for start section is also the shutdown completion section, the length of each section can be adjusted according to the tensioning requirement of the belt and the stroke of the hydraulic cylinder 8.

[0034] The displacement ratio of the piston rod of the hydraulic cylinder 8 to the displacement of the tensioning vehicle 11 is 1:0.5, that is, the stroke of the tensioning vehicle 11 is 0.5 units, and the stroke of the piston rod is 1 unit, that is, the stroke of the piston rod is twice the stroke of the tensioning vehicle 11.

[0035] To better help understand this embodiment, the four actions and the corresponding four pressure values in the embodiment using existing technology and appearing in the steps of this embodiment are described, the four actions are preparation for start, start completion, preparation for shutdown and shutdown completion, the pressure values and the size order of the hydraulic system set for the four actions are in turn: preparation for start value > start completion value > preparation for shutdown value > shutdown completion value, the setting and control of the pressure values of the four actions are based on existing mature technology, and this embodiment will not be described in detail.

[0036] The stroke control method of the hydraulic cylinder of the belt conveyor tensioning device comprises a belt conveyor starting stage control process and a belt conveyor stopping stage control process.

[0037] The belt conveyor starting stage control process comprises the following steps:

[0038] Step 11: Before the conveying process is started, the PLC sends a preparation starting signal to the belt conveyor, but the belt conveyor does not operate.

[0039] Step 12: The position of the piston rod of the hydraulic cylinder 8 is detected by the displacement sensor to determine whether it is in the preparation starting segment of the piston rod. If yes, the next step is entered. If no, the hydraulic pump 1 is started to control the piston rod of the hydraulic cylinder 8 to extend or retract to the preparation starting segment through the three-position four-way electromagnetic reversing valve 4.

[0040] Step 13: The on-off valve 6 is actuated to cut off the pipeline of the rod cavity of the hydraulic cylinder 8, and the hydraulic cylinder 8 is in a locked state to fix the position of the piston rod of the hydraulic cylinder 8. Due to the cutting off of the on-off valve 6, the hydraulic pump 1 can only charge the accumulator 15 through the three-position four-way electromagnetic reversing valve 4 and the hydraulic control check valve 5.

[0041] Step 14: The winch 9 is started to gradually tighten the steel wire rope 10, and the belt 13 of the belt conveyor is tightened through the tensioning vehicle 11. At this time, because the hydraulic cylinder 8 is locked in the hydraulic system, the tension of the belt 13 is displayed through the first pressure sensor 14 connected to the rod cavity of the hydraulic cylinder 8. When the detection value of the first pressure sensor reaches the preparation starting value, the winch 9 stops operating. When the detection value of the second pressure sensor reaches the preparation starting value, the hydraulic pump 1 stops.

[0042] Step 15: The on-off valve is opened, and the hydraulic cylinder 8 is unlocked. At this time, the values of the first pressure sensor 14 and the second pressure sensor 16 are equal, both being the preparation starting value. After the on-off valve 6 is opened, the load of the hydraulic cylinder 8 does not change, and the displacement of the piston rod of the hydraulic cylinder 8 also remains unchanged at the position at the end of step 12.

[0043] Step 16: The belt conveyor is started. Because the head wheel of the belt conveyor starts to drive, the upper belt of the belt conveyor is tightened through friction, and the lower belt forms a slack side. The load of the belt 13 on the hydraulic cylinder 8 is rapidly reduced, the balance in step 15 is broken, and the piston rod of the hydraulic cylinder 8 rapidly retreats due to the pressure relief of the accumulator 15. In order to keep the preparation starting value unchanged, the hydraulic pump 1 is started to control the piston rod of the hydraulic cylinder 8 to actively retract through the three-position four-way electromagnetic reversing valve 4, the belt 13 is tightened through the steel wire rope 10, and the detection value of the first pressure sensor 14 is stopped after reaching the preparation starting value and remaining stable without fluctuation.

[0044] Step 17: the proportional relief valve 18 is decompressed until the pressure of the accumulator 15 reaches the start completion value and remains stable. The position of the piston rod of the hydraulic cylinder 8 is detected by the displacement sensor 7. If the position is in the normal operation section, the belt conveyor is started and normal operation is started. If the position is not in the normal operation section, the winch 9 is started. The hydraulic pump 1 is started under the condition that the hydraulic system remains unchanged at the normal operation value. The winch 9 stops after the piston rod of the hydraulic cylinder 8 is controlled by the three-position four-way electromagnetic reversing valve 4 to move to the normal operation section. The hydraulic pump 1 stops, and the belt conveyor enters the normal operation mode. In order to avoid frequent starting of the winch 9, the length of the normal operation section is set to 70% to 80% of the full stroke of the piston rod of the hydraulic cylinder 8.

[0045] The purpose of the cylinder stroke control process of the belt conveyor in the starting stage is to keep the piston rod of the hydraulic cylinder 8 extended enough when the belt conveyor is ready to start. The piston rod of the hydraulic cylinder 8 needs to retreat to leave enough effective stroke when the belt conveyor is started. At the same time, it is also necessary to avoid the piston rod of the hydraulic cylinder 8 being extended too much before the belt conveyor is started, so as to enter the upper limit warning section. If the piston rod of the hydraulic cylinder 8 enters the upper limit warning section, the piston may contact the front end cover of the cylinder body, which not only easily causes damage to the cylinder, but also the force generated by the contact cannot be detected and measured. The pressure value displayed by the system cannot truly reflect the tension of the belt conveyor. At this time, the actual tension of the steel wire rope 10 and the belt 13 is greater than the system display value, which not only affects the service life of the belt conveyor, but also has serious safety hazards.

[0046] The control process of the belt conveyor in the shutdown stage includes the following steps:

[0047] Step 21: before the conveying process is stopped, the PLC sends a signal to the belt conveyor to allow shutdown, but the belt conveyor still operates;

[0048] Step 22: the winch 9 is started to release the steel wire rope 10. The hydraulic pump 1 is started under the condition that the hydraulic system remains unchanged at the start completion value. The piston rod of the hydraulic cylinder 8 is controlled by the three-position four-way electromagnetic reversing valve 4 to retract to the preparation shutdown section.

[0049] Step 23: the on-off valve 6 is actuated to cut off the rod cavity pipeline of the hydraulic cylinder 8, and the hydraulic cylinder 8 is in a locked state. The position of the piston rod of the hydraulic cylinder 8 is fixed.

[0050] Step 24: the proportional relief valve 18 is decompressed until the pressure of the accumulator 15 reaches the preparation shutdown value and remains unchanged.

[0051] Step 25: the on-off valve 6 is opened, and the hydraulic cylinder 8 is unlocked; due to the communication with the accumulator 15, the pressure of the hydraulic cylinder 8 is rapidly reduced to the preparation shutdown value at this time, which is lower than the start-up completion value corresponding to the load of the belt 13 before the on-off valve 6 is opened, in order to maintain the new balance, the piston rod of the hydraulic cylinder 8 will be rapidly extended for a distance to release the load until the pressure and the load are balanced again; the proportional overflow valve 18 starts to reduce the pressure to the preparation shutdown value of the accumulator 15; during this process, the piston rod of the hydraulic cylinder 8 will be extended for the second time until the load and the pressure (preparation shutdown value) are stable and then stop extending;

[0052] Step 26: the belt conveyor is stopped; because the head wheel of the belt conveyor stops rotating, the driving force disappears, the slack edge formed by the driving force will rebound quickly, the slack edge disappears, the load on the hydraulic cylinder 8 increases, and the pressure of the hydraulic system will rise;

[0053] Step 27: the proportional overflow valve reduces the pressure again to the shutdown completion value of the accumulator 15; the piston rod of the hydraulic cylinder 8 will be extended for the third time until the load and the pressure (shutdown completion value) are stable and then stop extending;

[0054] Step 28: check whether the position of the piston rod of the hydraulic cylinder 8 reaches the upper limit warning section through the displacement sensor 7; if not, the belt conveyor is stopped; if yes, start the winch 9 to release the steel wire rope 10, so that the piston rod of the piston rod is retracted to the shutdown completion section, and the belt conveyor is stopped.

[0055] The present application is not limited to the above-mentioned embodiments. Any technical solution formed by equivalent replacement falls within the protection scope of the present application.

Claims

1. A method for controlling the stroke of a hydraulic cylinder of a belt conveyor tensioning device, the belt conveyor tensioning device comprising: Hydraulic cylinder, winch, hydraulic pump, oil tank and accumulator; The piston rod of the hydraulic cylinder is connected with the winch through a steel wire rope, the steel wire rope is wound on a pulley block, one end of the pulley block is fixed, and the other end is connected with a tensioning vehicle of the belt conveyor; the hydraulic pump connects the oil tank and the hydraulic cylinder through a pipeline to drive the piston rod of the hydraulic cylinder to extend or retract; the hydraulic pump is provided with a reversing valve on the pipeline connected with the hydraulic cylinder; a on-off valve is arranged on the pipeline between the reversing valve and the rod cavity of the hydraulic cylinder; a hydraulic control check valve is arranged on the pipeline between the on-off valve and the reversing valve; the pipeline between the on-off valve and the hydraulic control check valve is further connected with the accumulator; the accumulator is connected with the oil tank through a pipeline; an electromagnetic ball valve, a proportional overflow valve and a throttle valve are arranged in sequence on the pipeline between the accumulator and the oil tank; the pipeline between the throttle valve and the oil tank is further connected with the reversing valve; the pipeline between the throttle valve and the oil tank is further connected to the pipeline between the hydraulic pump and the reversing valve through an overflow valve; the hydraulic cylinder is provided with a displacement sensor capable of detecting the movement distance of the piston rod; a first pressure sensor is arranged on the pipeline between the on-off valve and the hydraulic cylinder; a second pressure sensor is arranged on the pipeline between the accumulator and the electromagnetic ball valve; The hydraulic cylinder stroke control method comprises a belt conveyor starting stage control process and a belt conveyor stopping stage control process; The belt conveyor starting stage control process comprises the following steps: Step 11: the belt conveyor is prepared to start; Step 12: whether the position of the piston rod of the hydraulic cylinder is in the prepared starting section of the piston rod is detected by the displacement sensor; if yes, the next step is entered; if not, the hydraulic pump is started, and the piston rod of the hydraulic cylinder is controlled to extend or retract to the prepared starting section through the reversing valve; Step 13: the on-off valve cuts off the pipeline of the rod cavity of the hydraulic cylinder, the hydraulic cylinder is in a locked state, and the position of the piston rod of the hydraulic cylinder is fixed; the hydraulic pump charges the accumulator through the reversing valve and the hydraulic control check valve; Step 14: the winch is started to gradually tighten the steel wire rope, and the belt of the belt conveyor is tightened through the tensioning vehicle; when the detection value of the first pressure sensor reaches the prepared starting value, the winch stops; when the detection value of the second pressure sensor reaches the prepared starting value, the hydraulic pump stops; Step 15: the on-off valve is opened, and the hydraulic cylinder is unlocked; Step 16: the belt conveyor is started; the hydraulic pump is started, the piston rod of the hydraulic cylinder is actively retracted through the reversing valve, the belt is tightened through the steel wire rope, and the process is stopped when the detection value of the first pressure sensor reaches the prepared starting value and remains stable without fluctuation. Step 17: the proportional relief valve is decompressed until the accumulator pressure reaches the start complete value and remains stable, and the position of the hydraulic cylinder piston rod is detected by the displacement sensor to determine whether it is in the normal running section, if yes, the belt conveyor is started and runs normally; if not, the winch is started, the hydraulic pump is started, and the hydraulic cylinder piston rod is controlled to run to the normal running section by the reversing valve, then the winch stops, the hydraulic pump stops, and the belt conveyor enters the normal running mode; The belt conveyor shutdown stage control process comprises the following steps: Step 21: before the conveying process stops, the belt conveyor is prepared for shutdown; Step 22: the winch is started, the steel wire rope is released, the hydraulic pump is started, and the hydraulic cylinder piston rod is controlled to retract to the shutdown preparation section by the reversing valve; Step 23: the on-off valve cuts off the rod cavity pipeline of the hydraulic cylinder, and the hydraulic cylinder is in a locked state; the position of the hydraulic cylinder piston rod is fixed; Step 24: the proportional relief valve is decompressed until the accumulator pressure reaches the shutdown preparation value and remains stable; Step 25: the on-off valve is opened, and the hydraulic cylinder locking is released; Step 26: the belt conveyor is shut down; the proportional relief valve starts to decompress until the accumulator pressure reaches the shutdown preparation value; Step 27: the proportional relief valve is decompressed until the accumulator pressure reaches the shutdown complete value; Step 28: the position of the hydraulic cylinder piston rod is checked by the displacement sensor to determine whether it reaches the upper limit warning section, if not, the belt conveyor is shut down completely, if yes, the winch is started to release the steel wire rope, the hydraulic cylinder piston rod is retracted to the shutdown complete section, and the belt conveyor is shut down completely.

2. The hydraulic cylinder stroke control method of claim 1, wherein: The full stroke of the hydraulic cylinder piston rod from retraction to the limit position to extension to the limit position is divided into five sections in sequence, which are the lower limit warning section, the shutdown preparation section, the normal running section, the start preparation section, and the upper limit warning section, and the start preparation section is also the shutdown complete section.

3. The hydraulic cylinder stroke control method of claim 1, wherein: The start preparation value is greater than the start complete value, which is greater than the shutdown preparation value, which is greater than the shutdown complete value.

Images