CN116620791A - Chain skip protection system and protection method for scraper conveyor - Google Patents

Abstract

The invention discloses a chain skipping protection system and a protection method for a scraper conveyor. The system includes a sprocket vertical fine-tuning mechanism, a stress sensor, a weighing sensor, and a laser ranging sensor. The sensor is also connected with a signal conditioning box to realize Convert various sensor signals into signals recognizable by the industrial computer, and then the upper computer recognizes the meshing state of the scraper chain and the sprocket based on the data signal input by the industrial computer, the chain tension of the scraper conveyor, and the threshold of the overhang amount, and realizes chain skipping monitoring , also includes a vertical tensioning hydraulic cylinder and a constant velocity universal drive shaft structure, which can change the amount of oil entering the hydraulic cylinder in real time to control the vertical displacement of the sprocket. This method converts digital signals into current signals recognizable by the servo valve through the signal conditioning system, realizes the coordinated control of the horizontal and vertical tensioning hydraulic cylinders, and at the same time ensures the real-time control of the tension force of the scraper chain and the control of the scraper conveyor. The protection of the machine jump chain better guarantees the reliable and stable operation of the scraper conveyor.

Description

Chain skip protection system and protection method for scraper conveyor

technical field

The present application relates to the technical field of scraper conveyor monitoring and safety assurance, in particular to a chain-jumping protection system and protection method for scraper conveyors.

Background technique

Scraper conveyor, as a mining continuous transportation equipment that uses scraper chains to transport coal, undertakes the important tasks of transporting coal, providing moving fulcrums for hydraulic supports, and providing walking tracks for shearers. Its reliability directly affects to the safe and efficient production of modern coal mines.

The chain is the most prone to failure mechanism of the scraper conveyor, and its failures (broken chain, skipped chain, and dropped chain, etc.) account for about 21.1% of the total number of scraper conveyor failures. Once the scraper conveyor chain has a fault such as chain jumping, the maintenance time required is long, which seriously restricts the production efficiency of large coal mines in my country. At present, at home and abroad, the chain tension of the scraper conveyor and the tension of the hydraulic cylinder are obtained indirectly through the oil cylinder pressure, chain overhang and load torque. During the operation of the scraper conveyor, only the total tension of all chains of the scraper conveyor can be obtained through the pressure and power of the oil cylinder, and it is difficult to effectively monitor the tension of each chain. The chain of the scraper conveyor realizes the transportation of coal through the infinite closed-loop movement, and the traditional wired measurement method is difficult to realize the real-time direct monitoring of the chain tension. The invention patent titled "A Chain Tension Monitoring Device and Method for Scraper Conveyor" with the publication number CN105928653A discloses a chain tension monitoring device and method for scraper conveyors. The monitoring of chain tension is transformed into real-time detection of sprocket stress, and based on the collected stress data, it is judged whether the chain tension exceeds the limit, whether there is a broken chain, and the specific chain where the broken chain occurs. This monitoring method is flexible and reliable, but the scope of application is limited. It can only be used to observe the broken chain of the scraper conveyor, and cannot quickly and accurately identify the chain skipping and other situations.

The above problems urgently need to be resolved.

Contents of the invention

In view of the deficiencies in the prior art, the purpose of the present invention is to provide a chain skipping protection system for scraper conveyors to solve the problems raised in the background art above.

According to one aspect of the present application, a chain skipping protection system for a scraper conveyor includes a sprocket vertical fine-tuning mechanism, a slot in the middle of the scraper conveyor, a load cell, a horizontal tensioning hydraulic cylinder, a vertical tensioning hydraulic cylinder, The laser ranging sensor and peripheral host computer, industrial computer and signal conditioning box, the right side of the sprocket vertical fine-tuning mechanism is fixedly connected with the motor of the scraper conveyor, the motor is fixed, and the scraper conveyor The sprocket is set on the sprocket base through the rotation of the sprocket shaft, and the sprocket base is movable, the left side of the sprocket vertical fine-tuning mechanism is connected with the sprocket shaft, and the sprocket wheel A stress sensor is installed on the side of the tooth, a laser distance measuring sensor is installed on one side of the vertical fine-tuning mechanism of the sprocket, a weighing sensor is installed in the middle groove of the scraper conveyor, and the vertical fine-tuning mechanism of the sprocket It is fixedly connected with the vertical extension end of the vertical tensioning hydraulic cylinder, the bottom of the vertical tensioning hydraulic cylinder is connected with the ground through slide rails, and the vertical tensioning hydraulic cylinder can move laterally synchronously with the sprocket base , the horizontal tensioning hydraulic cylinder is installed horizontally on the ground, the extended end of the horizontal tensioning hydraulic cylinder is fixedly connected with the sprocket base, and the stress sensor is used to measure the tension of the chain under different tensions during the operation of the scraper conveyor. The stress data of the sprocket teeth, the load cell is used to measure the weight of coal falling in each operation cycle of the scraper conveyor, and the laser distance measuring sensor is used to measure the meshing point of the sprocket chain to the scraper The vertical distance of the trough in the middle of the conveyor, the stress sensor, load cell and laser ranging sensor are all electrically connected to the signal conditioning box, the signal conditioning box is electrically connected to the industrial control machine, and the industrial control machine is electrically connected to the upper machine , and the signal conditioning box can condition the output signals of the stress sensor, load cell and laser ranging sensor into a voltage signal recognizable by the industrial computer, and the industrial computer converts the stress signal through the TCP/IP protocol The data collected by sensors, load cells and laser ranging sensors are transmitted to the host computer.

Preferably, the sprocket vertical fine-tuning mechanism includes a connector, a stress sensor, a sprocket shaft and a constant velocity universal drive shaft structure, and the extended end of the vertical tension hydraulic cylinder is connected to the constant velocity universal drive shaft through the connector. The shaft structure is fixedly connected, the constant velocity universal drive shaft structure is fixedly connected with the sprocket shaft, and the constant velocity universal drive shaft structure is fixedly connected with the output shaft of the motor of the scraper conveyor.

Preferably, the constant velocity cardan shaft structure includes an intermediate shaft, a universal adjustment member, a steering shaft, a connecting plate, a connecting shaft and a gear box, and the universal adjustment member is connected to the vertical tensioner through the connector. The extended end of the hydraulic cylinder is fixedly connected, the universal adjustment part is fixedly connected with the sprocket shaft through the intermediate shaft, the universal adjustment part is connected with a ball joint at one end of the steering shaft, and the other end of the steering shaft is connected through a gear It is meshed with the gear box for transmission connection, and the gear box is fixedly connected with the connecting plate through the connecting shaft, and the connecting plate is fixedly connected with the output shaft of the motor.

Preferably, a digital signal conversion module and a control signal conversion module are arranged in the industrial computer, an analog input conditioning module and an analog output conditioning module are arranged in the signal conditioning box, and the analog input conditioning module converts the The output signals of the load cell and the laser ranging sensor are transmitted to the industrial computer through the digital signal conversion module, and the industrial computer sends a control signal to drive the servo valve through the control signal conversion module and the analog output conditioning module, Thereby controlling the oil output to the vertical tensioning hydraulic cylinder and the horizontal tensioning hydraulic cylinder for adjusting the tension of the chain, the industrial computer can collect the load cell and the laser distance sensor The acquired data is transmitted to the host computer through the TCP/IP protocol for calculation and storage, and the data collected by the stress sensor is transmitted to the host computer through Gigabit Ethernet by the DH5960 data collector.

Preferably, the laser ranging sensor is a ZYT-405 area ranging detection control sensor, and the horizontal tensioning hydraulic cylinder and the vertical tensioning hydraulic cylinder are both servo valve-controlled hydraulic cylinders.

A protection method for a chain skipping protection system of a scraper conveyor, specifically comprising the following steps:

In a working cycle of the scraper conveyor, the relationship model between the chain tension of the scraper conveyor and the stress at the installation position of the stress sensor is established through the dynamic principle; the installed stress sensor is calibrated by the external standard tension sensor, and the stress The output of the sensor obtains the chain tension of the scraper conveyor; using the derived dynamic model, the tension force of the horizontal tensioning hydraulic cylinder is obtained according to the obtained chain tension and the data measured by the load cell, so as to control the horizontal tensioning hydraulic cylinder The expansion and contraction of the scraper conveyor chain is controlled to tighten the chain in the horizontal direction;

Use the laser ranging sensor to measure the vertical distance from the lower meshing point of the sprocket and the chain to the bottom plate of the groove in the middle of the scraper conveyor; determine whether the chain has a chain skipping fault by discriminating the fault of the scraper conveyor; when determining the chain skipping fault Based on the data measured by the laser ranging sensor, the stress sensor and the load cell, the tension force of the vertical tension hydraulic cylinder is obtained, and the vertical tension hydraulic cylinder is controlled to elongate to control the upward movement of the sprocket. The chain prevents chain jump accidents from happening.

Preferably, the correlation model between the chain tension and the stress at the installation position of the stress sensor is to measure the tension of the scraper conveyor chain in real time and the stress change at the corresponding position on the tooth side of the sprocket by installing the stress sensor on the tooth side of the sprocket wheel , so as to realize the measurement of the chain tension.

Preferably, the derivation process of the kinetic model includes:

The torque balance equation of the sprocket is:

In formula (1), θ _m and θ _s are the angular displacement of the driving device and the sprocket respectively; J _m is the equivalent moment of inertia of the tail sprocket driving device; B _m is the damping coefficient; M _m and M _s are respectively The output torque of the motor and the load torque of the sprocket; Z _s is the transmission ratio of the gear reducer; R ₀ is the radius of the pitch circle of the sprocket, μ is the surface friction coefficient of the middle groove, G is the weight of random coal drop, L is the machine head Tail sprocket center distance;

Combining the linear mass density λ of the chain and the boundary condition y′(L-a/2)=0, the catenary sag equation of the EF section at the tail side is established as:

Wherein, a is the length of the catenary in the horizontal direction; T _F is that the chain tension of the F point is measured by the stress sensor (1.2);

Combining equations (1) and (2) and decomposing them along the horizontal and vertical directions, the tension forces of the horizontal and vertical tensioning hydraulic cylinders are respectively:

F _h (T _F , G, h _E , h _B ) = (μGL/R ₀ -T _F /cosα)/cosβ+T _F formula (3)

F _v (T _F , G, h _E , h _B ) = (μGL/R ₀ -T _F /sinα)/sinβ formula (4)

In the formula, the meshing angles α and β can be obtained by chain configuration analysis:

Among them, S ₁ and S ₂ are the chain lengths of the loaded and unloaded sides, respectively, h _B and h _E are the sagging of the loaded and unloaded side chains, respectively.

Preferably, the falling coal weight G is regarded as a fixed value and is measured by the load cell, the chain tension T _F is measured by the stress sensor, and the sagging h _B and h _E are both measured by the laser measured by the sensor.

Preferably, the specific steps of the fault identification of the scraper conveyor are:

(a) First, set the vertical distance from the lower meshing point of the sprocket and the chain to the bottom plate of the middle groove of the scraper conveyor and the safety threshold of the chain tension value as X and Y according to the historical data of the normal operation of the scraper conveyor ;

(b) Then, determine whether the vertical distance from the lower meshing point of the scraper conveyor sprocket and the chain to the bottom plate of the middle groove of the scraper conveyor and whether the chain tension value T is greater than the set safety thresholds X and Y are judged specifically. Methods as below:

(b1) If all are no, the industrial computer outputs a signal that the tension has not exceeded the limit;

(b2) If the vertical distance from the lower meshing point of the sprocket and the chain to the bottom plate of the trough in the middle of the scraper conveyor is lower than the safety threshold X and the ratio of the chain tension T to the tension threshold Y changes suddenly, the industrial computer outputs the scraper conveyor Machine broken link determination signal;

(b3) If the vertical distance from the lower meshing point of the sprocket and the chain to the bottom plate of the trough in the middle of the scraper conveyor does not exceed the safety threshold X but the chain tension value T exceeds the set safety threshold Y, the industrial computer outputs the scraper Conveyor stuck chain judgment signal;

(b4) If all are yes, the industrial computer outputs a chain skipping judgment signal of the scraper conveyor;

(c) Finally, once the host computer receives the chain skipping determination signal of the scraper conveyor, it controls the vertical tensioning hydraulic cylinder to move upwards to drive the sprocket to tighten the chain to prevent chain skipping accidents.

Compared with prior art, the advantage of the present invention is:

(1) Compared with the single horizontal adjustment mode of the chain tension of the traditional scraper conveyor, the present invention designs a sprocket vertical fine-tuning mechanism, and utilizes the constant velocity cardan shaft structure and the vertical tensioning hydraulic cylinder to realize the vertical adjustment of the sprocket. Fine adjustment is used to tension the chain, and because the universal adjustment device of the constant velocity cardan shaft structure and the steering shaft are connected by a precision ball joint, slight misalignment easily occurs when the mechanical parts cooperate, and it is easier to realize the meshing of the sprocket and the chain.

(2) The present invention converts the monitoring of the chain tension of the scraper conveyor into the real-time detection of the sprocket stress, and judges the fault condition of the scraper conveyor chain based on the on-line monitoring of the chain tension and the overhang amount, and utilizes horizontal and vertical tensioning hydraulic pressure The cylinder controls its operating state.

(3) The present invention not only designs a chain skipping protection method for scraper conveyors, but also designs a chain tension adjustment method based on time-varying loads during normal operation of scraper conveyors, which is beneficial to improve the chain tension of scraper conveyors. Reliability and safety of operation.

Description of drawings

Fig. 1 is a schematic structural diagram of a chain skipping protection system for a scraper conveyor according to an embodiment of the present application.

Fig. 2 is a schematic structural diagram of a sprocket vertical fine-tuning mechanism of a chain skipping protection system for a scraper conveyor according to an embodiment of the present application.

Fig. 3 is a control schematic diagram of a chain skipping protection system for a scraper conveyor according to an embodiment of the present application.

Fig. 4 is a schematic diagram of the dynamics of a chain skipping protection system for a scraper conveyor according to an embodiment of the present application.

Reference signs: 1, sprocket vertical fine-tuning mechanism; 1.1, connector; 1.2, stress sensor; 1.3, sprocket shaft; 1.4, intermediate shaft; 1.5, universal adjustment member; 1.6, steering shaft; 1.7, connection plate; 1.8. Connecting shaft; 1.9. Gear box; 2. Slot in the middle of scraper conveyor; 3. Load cell; 4. Horizontal tension hydraulic cylinder; 5. Vertical tension hydraulic cylinder; 6. Laser distance measuring sensor; 7 , Host computer; 8, industrial computer; 9, signal conditioning box.

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

In order to make the content of the present application more clearly understood, the following will clearly and completely describe the technical solutions in the embodiments of the present application in conjunction with the drawings in the embodiments of the present application. It should be noted that the words "front", "rear", "left", "right", "upper" and "lower" used in the following description are based on the direction in accompanying drawing 2, and the words "inside" and "Outward" refers to a direction toward or away from, respectively, the geometric center of a particular component.

It should be noted that tension refers to the pulling force or traction force received inside an object or system, and its direction is usually along the axis or stretching direction of the object; tension refers to the force exerted on the surface of an object , usually to keep objects tightly connected or fixed;

The chain is usually under tension when it is in use. When the chain is under load or in motion, the inside of the chain will be pulled or pulled, which is the tension on the chain; the tension is applied through the tensioning device connected to the chain; In order to ensure that the chain is tightly connected, it is necessary to apply a certain tension to adjust the tightness of the chain to achieve the best state; when the tension on the chain is too small, the chain is prone to jumping or loosening. Therefore, when using When building a chain, it is necessary to maintain the proper balance of tension and tension to ensure the proper functioning of the chain.

As shown in Figures 1 to 2, a chain skip protection system for scraper conveyors includes a sprocket vertical fine-tuning mechanism 1, a slot in the middle of the scraper conveyor 2, a weighing sensor 3, a horizontal tensioning hydraulic cylinder 4, a vertical Straight tensioning hydraulic cylinder 5, laser ranging sensor 6, peripheral host computer 7, industrial computer 8 and signal conditioning box 9, the right side of sprocket vertical fine-tuning mechanism 1 is fixedly connected with the motor of the scraper conveyor, and the motor For fixed setting, the sprocket of the scraper conveyor is set on the sprocket base through the rotation of the sprocket shaft 1.3, and the sprocket base is movable, and the left side of the sprocket vertical fine-tuning mechanism 1 is connected with the sprocket shaft 1.3, A stress sensor 1.2 is installed on the tooth side of the sprocket, a laser distance measuring sensor 6 is installed on one side of the vertical fine-tuning mechanism 1 of the sprocket, a weighing sensor 3 is installed in the slot 2 in the middle of the scraper conveyor, and a vertical adjustment mechanism 1 of the sprocket is installed. The fine-tuning mechanism 1 is fixedly connected with the vertical extension end of the vertical tension hydraulic cylinder 5, the bottom of the vertical tension hydraulic cylinder 5 is connected with the ground through slide rails, and the vertical tension hydraulic cylinder 5 can be synchronized with the sprocket base Horizontal movement, the horizontal tensioning hydraulic cylinder 4 is installed horizontally on the ground, the extended end of the horizontal tensioning hydraulic cylinder 4 is fixedly connected with the sprocket base, and the stress sensor 1.2 is used to measure the different tensions of the chain during the operation of the scraper conveyor The stress data of the sprocket teeth below, the load cell 3 is used to measure the weight of coal falling in each operation cycle of the scraper conveyor, and the laser distance sensor 6 is used to measure the meshing point of the sprocket chain to the middle of the scraper conveyor The vertical distance of the groove 2, the stress sensor 1.2, the load cell 3 and the laser ranging sensor 6 are all electrically connected to the signal conditioning box 9, the signal conditioning box 9 is electrically connected to the industrial computer 8, and the industrial computer 8 is electrically connected to the upper computer 7. connection, and the signal conditioning box 9 can condition the output signals of the stress sensor 1.2, the load cell 3 and the laser distance sensor 6 into a voltage signal recognizable by the industrial computer 8, and the industrial computer 8 converts the stress sensor 1.2 through the TCP/IP protocol The data collected by the load cell 3 and the laser ranging sensor 6 are transmitted to the host computer 7. Specifically, the laser ranging sensor 6 selects the ZYT-405 area ranging detection control sensor, and the horizontal tension hydraulic cylinder 4 and the vertical The tensioning hydraulic cylinders 5 all use servo valve control hydraulic cylinders.

In one embodiment, referring to FIG. 2 , the sprocket vertical fine-tuning mechanism 1 includes a connector, a stress sensor 1.2, a sprocket shaft 1.3 and a constant velocity cardan shaft structure, and the extended end of the vertical tension hydraulic cylinder 5 is connected to The device is fixedly connected with the constant velocity universal drive shaft structure, the constant velocity universal drive shaft structure is fixedly connected with the sprocket shaft 1.3, and the constant velocity universal drive shaft structure is fixedly connected with the output shaft of the motor of the scraper conveyor, wherein the constant velocity The universal joint shaft structure includes an intermediate shaft 1.4, a universal adjustment member 1.5, a steering shaft 1.6, a connecting plate 1.7, a connecting shaft 1.8 and a gear box 1.9, and the universal joint adjustment member 1.5 is connected to the vertical tension hydraulic cylinder 5 through a connector. The output end is fixedly connected, the universal adjustment part 1.5 is fixedly connected with the sprocket shaft 1.3 through the intermediate shaft 1.4, the universal adjustment part 1.5 is connected with the ball joint at one end of the steering shaft 1.6, and the other end of the steering shaft 1.6 is meshed with the gear box 1.9 for transmission Connection, the gear box 1.9 is fixedly connected to the connecting disc 1.7 through the connecting shaft 1.8, and the connecting disc 1.7 is fixedly connected to the output shaft of the motor. In specific implementation, the motor can drive the gear box 1.9 through the connecting disc 1.7 and the connecting shaft 1.8, thereby driving the steering The shaft 1.6 rotates, and then drives the sprocket shaft 1.3 to rotate through the universal adjustment part 1.5 and the intermediate shaft 1.4, and then drives the sprocket to rotate.

In the above design, compared with the traditional single horizontal adjustment mode of the chain tension of the scraper conveyor, the present invention designs the sprocket vertical fine-tuning mechanism 1, and utilizes the constant velocity cardan shaft structure and the vertical tensioning hydraulic cylinder 5 to realize chain tension. The vertical fine-tuning of the wheel is used to tension the chain, and because the universal adjustment device of the constant velocity cardan shaft structure is connected with the steering shaft 1.6 through a precision ball joint, slight misalignment is likely to occur when the mechanical parts are matched, and it is easier to realize the sprocket engagement with the chain.

In one embodiment, referring to Fig. 3, a digital signal conversion module and a control signal conversion module are arranged in the industrial computer 8, and an analog input conditioning module and an analog output conditioning module are arranged in the signal conditioning box 9, specifically, digital signal The conversion module uses the AD board PCI-1716, the control signal conversion module uses the DA board PCI-6208, and the signal conditioning box 9 is provided with an analog input conditioning module and an analog output conditioning module, and the analog input conditioning module connects the load cell 3 and the 4-20mA current signal output by the laser ranging sensor 6 are converted into -10V-10V voltage signals that can be collected by the AD board PCI-1716, and then the AD board PCI-1716 transmits the signal to the industrial computer 8, and then the industrial computer 8 transmits the signal to the upper computer 7, and the digital signal calculated by the upper computer 7 based on the controller model obtained by the catenary theory and the dynamic principle is transmitted to the industrial computer 8, and then the digital signal of the industrial computer 8 passes through the DA board PCI -6208 is transformed into a voltage signal of -10V ~ 10V, and converted into a current signal of -40mA ~ 40mA through the analog output conditioning module to drive the servo valve, which can control the vertical tension hydraulic cylinder 5 and the horizontal tension hydraulic cylinder 4 oil, and then control the oil output to the vertical tension hydraulic cylinder 5 and the horizontal tension hydraulic cylinder 4 to realize the adjustment of the chain tension. The industrial computer 8 can load the load cell 3 and the laser range sensor 6 The collected data is transmitted to the upper computer 7 through the TCP/IP protocol, and the data collected by the stress sensor 1.2 is transmitted to the upper computer 7 by the DH5960 data collector through Gigabit Ethernet.

Figure 4 is a schematic diagram of the dynamics of the scraper chain tensioning device of a scraper conveyor skip chain protection system. The sprocket drives the chain through the meshing force. The moment balance equation of the sprocket is:

In formula (1), θ _m and θ _s are the angular displacement of the driving device and the sprocket respectively; J _m is the equivalent moment of inertia of the tail sprocket driving device; B _m is the damping coefficient; M _m and M _s are respectively The output torque of the motor and the load torque of the sprocket; Z _s is the transmission ratio of the gear reducer; R ₀ is the radius of the pitch circle of the sprocket, μ is the surface friction coefficient of the middle groove, and G is the weight of random falling coal measured by the load cell 3 Obtained, L is the center-to-center distance of the nose and tail sprockets.

Assuming that the quality of the chain is uniform, the chain on the unloaded side is supported by the bottom plate of the middle groove, and the chain on the unloaded side of the tail is in a hanging state. Therefore, the meshing angle of the chain at point E is deduced by using the catenary equation. According to Fig. 3, in combination with the linear mass density λ of the chain and the boundary condition y'(L-a/2)=0, the catenary sag equation of the EF section at the tail side can be established as:

Among them, a is the length of the catenary in the horizontal direction; T _F is the chain tension at point F measured by the stress sensor 1.2, and the catenary refers to the chain connected to the scraper in the scraper conveyor.

Combining equations (1) and (2) and decomposing them along the horizontal and vertical directions, the tension forces of the horizontal and vertical tensioning hydraulic cylinders are respectively:

F _h (T _F , G, h _E , h _B ) = (μGL/R ₀ -T _F /cosα)/cosβ+T _F formula (3)

F _v (T _F , G, h _E , h _B ) = (μGL/R ₀ -T _F /sinα)/sinβ formula (4)

In the formula, the meshing angles α and β can be obtained by chain configuration analysis:

Among them, S ₁ and S ₂ are the chain lengths of the loaded and unloaded sides respectively, h _B and h _E are the chain sags of the loaded and unloaded sides respectively, both of which are measured by the laser ranging sensor 6 .

The working principle of the control of the present invention:

(1) Relationship between chain tension and sprocket stress

The scraper conveyor drives the movement of the chain through the rotating sprocket to realize the transportation of coal. The tension of the chain is directly related to the deformation of the side of the sprocket, such as: the tension between the chains and the sudden change in tension caused by chain skipping and chain tension Unbalance and so on can be expressed in real time through the stress value at the corresponding position of the sprocket. Measuring chain tension is achieved by correlating the tension of the scraper conveyor chain with stress changes at key locations on the sprocket teeth.

(2) Set the threshold for fault detection

In the working process of the scraper conveyor, a certain working cycle is taken, and the tension and overhang of the scraper chain in each cycle have a certain rated value. If the rated value exceeds a certain range, a chain skipping fault will occur under extreme overload conditions. Through Setting tension and sag thresholds enables fault detection of skipped chains.

(3) The industrial computer 8 controls the movement of the hydraulic cylinder

In each working cycle, the coal weight G can be regarded as a fixed value and can be measured by the load cell 3, and the chain tension T _F and the sagging h _E and h _B can be measured by the stress sensor 1.2 and the laser distance sensor 6 respectively. After the measured output signals of various sensors are adjusted to voltage signals recognizable by the industrial computer 8, all data are transmitted to the upper computer 7 through the TCP/IP protocol, and the upper computer 7 combines the above-mentioned horizontal and vertical tensioning hydraulic cylinders. The tightening force model converts the received data instructions into corresponding digital signals, and then the signal conditioning box 9 converts them into current signals to drive the servo valve, and then controls the oil output to the horizontal and vertical tensioning hydraulic cylinders 5 to realize the tension of the hydraulic cylinders. Movement control.

A protection method for a chain skipping protection system of a scraper conveyor, specifically comprising the following steps:

First, the tension force of the horizontal tension hydraulic cylinder 4 is obtained by adjusting the tension of the scraper conveyor chain, thereby controlling the expansion and contraction of the horizontal tension hydraulic cylinder to control the expansion and contraction of the scraper conveyor chain; then, by adjusting the vertical tension of the sprocket Fine-tune to obtain the tension of the vertical tension hydraulic cylinder 5, so as to control the upward movement of the sprocket and tighten the chain to prevent chain skipping accidents. Chain failure.

Specifically, the specific steps for adjusting the chain tension of the scraper conveyor are as follows: First, within a working cycle of the scraper conveyor, a correlation model between the tension of the scraper conveyor chain and the stress at the installation position of the stress sensor 1.2 is established through the dynamic principle ( As shown in Figure 4 and the above description); then, the installed stress sensor 1.2 is calibrated by an external standard tension sensor, and the chain tension of the scraper conveyor is obtained through the output of the stress sensor 1.2; finally, use the derived power According to the obtained chain tension and the data measured by the load cell 3, the tension force of the horizontal tension hydraulic cylinder 4 is obtained, thereby controlling the expansion and contraction of the horizontal tension hydraulic cylinder 4 to control Telescoping of the scraper conveyor chain.

Specifically, the specific steps for vertical fine-tuning of the sprocket are as follows: First, on the basis of adjusting the chain tension of the scraper conveyor, use the laser ranging sensor 6 to measure the lower meshing point between the sprocket and the chain to the slot 2 in the middle of the scraper conveyor The vertical distance of the bottom plate; then, determine whether the chain skipping fault occurs by judging the fault of the scraper conveyor; finally, on the basis of determining the skipping fault, combine the laser distance sensor 6, the stress sensor 1.2 and the weighing sensor 3 Measure the data and obtain the tension force of the vertical tension hydraulic cylinder 5, control the sprocket wheel to move upwards and tighten the chain to prevent chain jumping accidents from taking place.

Specifically, the specific steps for the fault identification of the scraper conveyor are:

(a) First, set the vertical distance from the lower meshing point of the sprocket and the chain to the bottom plate of slot 2 in the middle of the scraper conveyor and the safety threshold of the chain tension value as X and Y according to the historical data of the normal operation of the scraper conveyor;

(b) Then, judge whether the vertical distance from the lower meshing point of the scraper conveyor sprocket and the chain to the bottom plate of the slot 2 in the middle of the scraper conveyor and whether the chain tension value T is greater than the set safety threshold X and Y, the specific judgment method as follows:

(b1) If all are no, the industrial computer 8 outputs a signal that the tension has not exceeded the limit;

(b2) If the vertical distance from the lower meshing point of the sprocket and the chain to the bottom plate of groove 2 in the middle of the scraper conveyor is lower than the safety threshold X and the ratio of the chain tension value T to the tension threshold Y changes suddenly, the output of the industrial computer 8 scraper conveyor is broken. Chain judgment signal;

(b3) If the vertical distance from the lower meshing point of the sprocket and the chain to the bottom plate of slot 2 in the middle of the scraper conveyor does not exceed the safety threshold X but the chain tension value T exceeds the set safety threshold Y, the industrial computer 8 outputs the scraper conveyor Card chain judgment signal;

(b4) If all are yes, the industrial computer 8 outputs the chain skipping judgment signal of the scraper conveyor;

(c) Finally, once the upper computer 7 receives the chain-jumping determination signal of the scraper conveyor, it controls the vertical tension hydraulic cylinder 5 to act, thereby driving the sprocket to move upwards and tighten the chain to prevent chain-jumping accidents.

The invention converts the monitoring of the chain tension of the scraper conveyor into the real-time detection of the stress of the sprocket, judges the fault condition of the chain of the scraper conveyor based on the online monitoring of the tension of the chain and the amount of overhang, and utilizes 5 pairs of horizontal and vertical tensioning hydraulic cylinders Its operating status is controlled.

The above embodiments are only used to illustrate the technical solutions of the embodiments of the present application, but not to limit them. Although the embodiments of the present application have been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that, without departing from the spirit and scope defined by the claims of the present application, they can still use the foregoing embodiments The recorded technical solutions are modified, or some of the technical features are equivalently replaced.

Claims (10)

1. The utility model provides a scraper conveyor jump chain protection system, includes sprocket vertical fine setting mechanism (1), scraper conveyor middle part groove (2), weighing sensor (3), horizontal tensioning pneumatic cylinder (4), vertical tensioning pneumatic cylinder (5), upper computer (7), industrial computer (8) and signal conditioning case (9) of laser rangefinder sensor (6) and peripheral hardware, its characterized in that, the right side of sprocket vertical fine setting mechanism (1) and scraper conveyor's motor fixed connection, the motor is fixed setting, scraper conveyor's sprocket passes through sprocket axle (1.3) rotation and locates on the sprocket base, just the sprocket base is movable setting, the left side of sprocket vertical fine setting mechanism (1) with sprocket axle (1.3) are connected, sprocket tooth side-mounting is equipped with stress sensor (1.2), sprocket vertical fine setting mechanism (1) one side is equipped with laser rangefinder sensor (6), install in scraper conveyor middle part groove (2) and be equipped with weighing sensor (3), sprocket vertical fine setting mechanism (1) and vertical tensioning cylinder (5) are connected with horizontal tensioning cylinder (5) and horizontal tensioning cylinder (5) are connected with horizontal tensioning cylinder (5) hydraulic cylinder and horizontal tensioning cylinder are connected, the utility model provides a horizontal tensioning pneumatic cylinder (4) stretch out end and sprocket base fixed connection, stress sensor (1.2) are used for measuring the stress data of sprocket teeth under the different tension of scraper conveyor operation in-process chain, weighing sensor (3) are used for measuring the coal weight that falls in every operation cycle of scraper conveyor, laser rangefinder sensor (6) are used for measuring sprocket chain meshing point extremely the perpendicular distance of scraper conveyor middle part groove (2), stress sensor (1.2), weighing sensor (3) and laser rangefinder sensor (6) all with signal conditioning case (9) electric connection, signal conditioning case (9) and industrial computer (8) electric connection, industrial computer (8) and host computer (7) electric connection, just signal conditioning case (9) can with the output signal conditioning of stress sensor (1.2), weighing sensor (3) and laser rangefinder sensor (6) is industrial computer (8) identifiable voltage signal, industrial computer (8) are passed through to TCP (8) and are passed through to weighing sensor (6) IP sensor (6) and are gathered to upper computer (7).

2. The chain jump protection system of a scraper conveyor according to claim 1, characterized in that the sprocket vertical fine adjustment mechanism (1) comprises a connector (1.1), a stress sensor (1.2), a sprocket shaft (1.3) and a constant velocity universal drive shaft structure, the extending end of the vertical tensioning hydraulic cylinder (5) is fixedly connected with the constant velocity universal drive shaft structure through the connector (1.1), the constant velocity universal drive shaft structure is fixedly connected with the sprocket shaft (1.3), and the constant velocity universal drive shaft structure is fixedly connected with an output shaft of a motor of the scraper conveyor.

3. The chain jump protection system of a scraper conveyor according to claim 2, characterized in that the constant velocity universal drive shaft structure comprises a middle shaft (1.4), a universal adjusting piece (1.5), a steering shaft (1.6), a connecting disc (1.7), a connecting shaft (1.8) and a gear box (1.9), wherein the universal adjusting piece (1.5) is fixedly connected with the extending end of the vertical tensioning hydraulic cylinder (5) through the connector (1.1), the universal adjusting piece (1.5) is fixedly connected with the chain wheel shaft (1.3) through the middle shaft (1.4), the universal adjusting piece (1.5) is in spherical hinge connection with one end of the steering shaft (1.6), the other end of the steering shaft (1.6) is in meshed transmission connection with a gear box (1.9), the gear box (1.9) is fixedly connected with the connecting disc (1.7) through the connecting shaft (1.8), and the connecting disc (1.7) is fixedly connected with the output shaft of the motor.

4. The chain jump protection system of the scraper conveyor according to claim 1, wherein a digital signal conversion module and a control signal conversion module are arranged in the industrial personal computer (8), an analog input conditioning module and an analog output conditioning module are arranged in the signal conditioning box (9), the analog input conditioning module transmits output signals of the weighing sensor (3) and the laser ranging sensor (6) to the industrial personal computer (8) through the digital signal conversion module, and the industrial personal computer (8) transmits control signals to drive a servo valve through the control signal conversion module and the analog output conditioning module, so that oil liquid output to the vertical tensioning hydraulic cylinder (5) and the horizontal tensioning hydraulic cylinder (4) is controlled to be used for adjusting chain tensioning force.

5. The chain jump protection system of the scraper conveyor according to claim 4, wherein the laser ranging sensor (6) is a ZYT-405 type regional ranging detection control sensor, and the horizontal tensioning hydraulic cylinder (4) and the vertical tensioning hydraulic cylinder (5) are both servo valve control type hydraulic cylinders.

6. The method for protecting a chain jump protecting system of a scraper conveyor according to any one of claims 1 to 5, comprising the following steps:

in one working period of the scraper conveyor, establishing a correlation model of chain tension of the scraper conveyor and stress at the installation position of a stress sensor (1.2) through a dynamics principle; the installed stress sensor (1.2) is calibrated through an external standard tension sensor, and the chain tension of the scraper conveyor is obtained through the output of the stress sensor (1.2); the tension of the horizontal tensioning hydraulic cylinder (4) is obtained according to the obtained chain tension and the data measured by the weighing sensor (3) by utilizing the derived dynamic model, so that the stretching of the horizontal tensioning hydraulic cylinder (4) is controlled to control the stretching of the chain of the scraper conveyor to stretch the chain in the horizontal direction;

measuring the vertical distance from the lower meshing point of the chain wheel and the chain to the bottom plate of the middle groove (2) of the scraper conveyor by using a laser ranging sensor (6); judging whether the chain has a chain jump fault or not through judging the fault of the scraper conveyor; on the basis of determining the chain jump fault, the tensioning force of the vertical tensioning hydraulic cylinder (5) is obtained by combining data measured by the laser ranging sensor (6), the stress sensor (1.2) and the weighing sensor (3), and the vertical tensioning hydraulic cylinder (5) is controlled to extend so as to control the chain wheel to move upwards to tension the chain, so that the chain jump accident is prevented.

7. The protection method of the chain jump protection system of the scraper conveyor according to claim 6, wherein the association model of the chain tension and the stress at the installation position of the stress sensor (1.2) is that the stress change of the corresponding positions of the chain tension of the scraper conveyor and the side surface of the sprocket tooth is measured in real time through the stress sensor (1.2) arranged on the side surface of the sprocket tooth, so that the measurement of the chain tension is realized.

8. The method of claim 6, wherein the derivation of the kinetic model comprises:

the moment balance equation of the chain wheel is as follows:

in the formula (1), θ _m And theta _s Angular displacement of the driving device and the sprocket respectively; j (J) _m Is a tail sprocketEquivalent moment of inertia of the driving device; b (B) _m Is a damping coefficient; m is M _m And M _s The output torque of the motor and the load torque of the chain wheel are respectively; z is Z _s Is the transmission ratio of the gear reducer; r is R ₀ The pitch circle radius of the chain wheel is mu, the friction coefficient of the surface of the middle groove is mu, G is the weight of randomly falling coal, and L is the center distance of the chain wheels at the tail of the machine head;

combining the linear mass density lambda of the chain and the boundary condition y' (L-a/2) =0, the suspension chain sag equation of the tail-side EF section is established as follows:

in the formula (2), a is the length of the catenary in the horizontal direction; t (T) _F The chain tension at the point F is measured by the stress sensor (1.2);

the formulas (1) and (2) are combined and decomposed along the horizontal and vertical directions to obtain the horizontal and vertical tensioning hydraulic cylinder tensioning forces which are respectively as follows:

F _h (T _F ，G，h _E ，h _B )＝(μGL/R ₀ -T _F /cosα)/cosβ+T _F formula (3)

F _v (T _F ，G，h _E ，h _B )＝(μGL/R ₀ -T _F Formula/sin alpha/sin beta (4)

Wherein the engagement angles alpha and beta can be obtained by chain configuration analysis:

in the formula (5), S ₁ And S is ₂ The chain lengths of the loaded side and the unloaded side are respectively h _B And h _E The chain sag is the load and no load side respectively.

9. The protection method of a chain jump protection system of a scraper conveyor according to claim 8, characterized in that the falling weight G is regarded as a constant value and passes through the load cell(3) Measured, the chain tension T _F The sagging amount h is measured by the stress sensor (1.2) _B And h _E Are all measured by the laser ranging sensor (6).

10. The protection method of the scraper conveyor chain jump protection system according to claim 6, wherein the specific steps of the scraper conveyor fault discrimination are as follows:

(a) Firstly, setting the vertical distance between the lower meshing point of a chain wheel and a chain and the bottom plate of a middle groove (2) of the scraper conveyor and the safety threshold value of the chain tension value as X and Y according to historical data under the normal operation condition of the scraper conveyor;

(b) Then, respectively judging whether the vertical distance from the lower engagement point of the chain wheel and the chain of the scraper conveyor to the bottom plate of the middle groove (2) of the scraper conveyor and the chain tension value T are larger than set safety thresholds X and Y, wherein the specific judging method is as follows:

(b1) If not, the industrial personal computer (8) outputs a tension non-overrun signal;

(b2) If the vertical distance from the lower meshing point of the chain wheel and the chain to the bottom plate of the middle groove (2) of the scraper conveyor is lower than a safety threshold value X and the ratio of the tension value T of the chain to the tension threshold value Y is suddenly changed, the industrial personal computer (8) outputs a scraper conveyor chain breakage judging signal;

(b3) If the vertical distance from the lower meshing point of the chain wheel and the chain to the bottom plate of the middle groove (2) of the scraper conveyor does not exceed the safety threshold X but the chain tension value T exceeds the set safety threshold Y, the industrial personal computer (8) outputs a scraper conveyor chain clamping judgment signal;

(b4) If both the signals are yes, the industrial personal computer (8) outputs a chain jump judging signal of the scraper conveyor;

(c) Finally, once the upper computer (7) receives the chain jump judging signal of the scraper conveyor, the vertical tensioning hydraulic cylinder (5) is controlled to act, so that the chain wheel is driven to move upwards to tension the chain, and the chain jump accident is prevented.