SU1189756A1 - Method of controlling the loading of conveyer - Google Patents

Description

The invention relates to the automation of continuous-transport systems and can be used in all areas of the national economy, where belt conveyors are used 5

. for transportation of bulk materials.

The purpose of the invention is to improve the control accuracy and reliability. the conveyor in work. ten

Usually, at the mining and processing works, the conveyor is loaded from a bunker of sufficient capacity close to the size of the load on the belt. The intensity of the traffic (the amount of cargo

per unit of time) entering a bunker varies considerably. According to the proposed method, the regulation of the speed of the conveyor is carried out in such a way that the average value of the intensity of the cargo flow entering the bunker corresponds to the average value of the intensity of the cargo flow coming off the conveyor. To maintain the nominal fill rate of the conveyor belt with cargo, the conveyor is loaded from a bunker, which is used as a hopper and buffer. When ^ 0 significant difference in average intensities entering the bunker

• and the cargo traffic coming down from the conveyor belt in the bunker accumulates part of the cargo, since the transition to 35

¹ rare (highest) level of speed carried out with a delay to time. Such "accumulation takes place before leveling the average intensities of the cargo flows coming from the conveyor belt 40 and entering the bukker. When the average cargo flow coming from the belt exceeds the average intensity of the cargo entering the bunker, the last one unloads. Since the load intensity entering the bunker varies with respect to the average value of the intensity of the incoming traffic, the amount of 50 cargo that exceeds the average value of the intensity of the incoming cargo traffic also remains (Accumulated) in the hopper, and at a time when the intensity of the incoming traffic 55 less than the average, this part of the accumulated load is unloaded onto a conveyor belt. Thus, we achieve the nominal filling conveyor belt.

In this case, the bunker plays the role of a buffer, i.e. smooths out. fluctuations in the intensity of the incoming traffic relative to its average intensity.

Since the incoming traffic is a random function, it can be characterized by the mathematical expectation of the intensity of the incoming traffic and the standard deviation. Since the incoming traffic is subject to considerable fluctuations, its expectation also fluctuates significantly. The oscillation at the input determines the same oscillations at the output, i.e. if the traffic flow at the entrance to the bunker fluctuates, then to ensure nominal filling with the load of the conveyor belt (within considerable limits) it is necessary to change the speed of the conveyor. If the average. the intensity of the cargo flow arriving at the conveyor at a certain time interval is constant, then at the same time interval the speed of the conveyor is also constant. In this case, the mode is stationary, stationary, which significantly affects the increase in the reliability of the conveyor, since dynamic overloads are excluded. To ensure the stationarity of the cargo traffic, two options are possible. In the first version, i.e. When using a large capacity bunker, an adequate changeable conveyor productivity does not influence the input intensity of the incoming cargo flow on the change in the conveyor speed.

In this case, the speed is a constant value. However, installing a bunker of such a large capacity is not economically viable. The second option is to divide the expectation function into ranges, where this function characterizes a stationary process. Based on the analysis of the static characteristics of the intensity of the cargo entering the bunker, the expectation function should be divided into six ranges. According to the six ranges set and six constant levels of speed. In order to make the transition from one level of speed to another without dynamic breakthrough 1189756

The bunker used at the mining and processing plants is divided into six ranges used to accumulate cargo, and the transition from one speed level to another takes place with acceleration or deceleration, determined by the filling time of the level in the bunker.

FIG. 1 shows a device that implements the proposed method, · 10

in fig. 2 - block diagram of the computing unit.

The device consists of a bunker 1, with fixed levels 1-6 of finding the cargo, dividing the volume of the bunker 15 into six ranges 1-νΐ of filling the bunker with cargo, conveyor 2, sensors 3 controlling the level of cargo in the bunker, computing unit 4, unit 5 of control driven coy-20

Weyer

The method is as follows.

According to six ranges, into which the expectation function is divided, six levels of finding the load 'in the bunker are fixed and six levels of speed 1-6 are set accordingly to these levels. The traffic flows into the bunker 1, from which the conveyor 2 is loaded. The sensors 3 monitor the respective levels of the load in the bunker. The outputs of these sensors 3 are connected to the corresponding inputs of the computing unit 4.

When the load reaches the first level at the first input of the sensors 3, a signal appears that goes to the first input of the computational * 0 unit 4. When the load reaches the second level, a second signal appears at the second output of the sensor 3, which then goes to the second input of block 4, etc. Unit 4 processes the received information * ⁵ and issues a signal to the conveyor drive control unit 5 about the speed level and the magnitude of acceleration or deceleration, if it is necessary to accelerate the conveyor to the next highest speed level or brake to the next lowest speed level. Unit 4 organizes the calculation of the filling time of the bunker ranges, by which ⁵⁵ it calculates the acceleration or deceleration for the drive of the conveyor.

When filling with the load of the range I, located between the bottom of the bunker and the first level 0-1 of finding the load, the speed of the conveyor is set equal to the first level, when filled with the load

range C, located between levels 1-2 of the location of the cargo, the speed of the conveyor is set equal to the second level ν ₂ · When filling the load range VI, ie when the load reaches the top (sixth) level, set the maximum speed of the conveyor corresponding to the sixth level. Moreover, when the volume of the bunker is divided into six ranges, the upper sixth range is emitted in such a way that when the load reaches the sixth level, the load in the bunker in the latter still leaves the volume corresponding to the maximum value

standard deviation in *

the intensity of the traffic from its expectation in this range, zone. The transition from one speed level to another is carried out with acceleration determined by the speed of filling with a load of the corresponding range. For example, when filling with a load of range 1 (the load reaches the “Level 1” mark), the conveyor is transferred to the speed of the first level with acceleration defined as

where is the acceleration with which the conveyor is displayed at the first speed level, ^-

V, is the velocity value corresponding to the first level;

- speed value corresponding to zero (minimum) level; the time it takes for the load to fill the Ϊ range in the bunker.

If the difference is ₊ , - V; (in general) the value is constant, then the acceleration is determined through the time of filling the range (1 + 1). Moreover, the transition in this case to the level of speed when the conveyor is accelerated is not made immediately when the load enters the range (1 + 1), but only after filling the latter with the load, i.e. with a delay determined by the filling time (1 + 1) interval.

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When the load reaches the top (sixth) level of the presence of cargo in the bunker, i.e. when filling the sixth range, transfer the conveyor to the maximum speed, the speed of the sixth level, without delay in time with starting acceleration.

The transfer of the conveyor to the upper level of speed ensures that the average intensity of the cargo traffic coming from the conveyor belt exceeds the average intensity of the cargo traffic entering the bunker,

When the average of 15 intensities is achieved, the traffic flows from the belt and the cargo flows entering the bunker must be unloaded; release the bunker from the accumulated cargo there. To do this, they transfer the conveyor to the next level of speed (higher than the one at which the equality of average intensity was achieved). For example, if the equality of the average intensities of the cargo traffic coming from the belt and entering the bunker is achieved at speed level V; (the level of the cargo in the bunker has ceased to increase), then for unloading the bunker the conveyor is transferred to the speed ^ ϊ _{+ 1} · At the same time, the acceleration to transfer to this level of speed is determined by the following procedure 40

where - £ - is the average unloading rate of the bunker range;

b - the volume of cargo located in this range ^ of the bunker ·,

r _raet is the range unloading time.

Since & ν = ₊ is

the value of a constant, the acceleration depends only on the time of loading the load range of the bunker. Transition to level V; 4, when unloading the bunker, it is produced with an acceleration value equal to the acceleration value, with which the conveyor was transferred to the speed level V; . At the same time the bunker unloads. Since a certain amount of cargo must always be in the bunker, the control point of the load (level ί) and the critical point of the load in the bunker at which the conveyor loading from the bunker is stopped and the conveyor (middle of the bunker range I) are set.

When unloading the bunker, the unloading time of each range in the bunker is measured and compared with the estimated time, i.e. in the meantime, for which the level in the bunker is unloaded at the speed & V - \ ί; _{+ 1} - V; _} since it is this difference in speed that allows you to unload the bunker. If4 p _{che [|} =

= ICM ( ^where ^ lnc. ~ estimated time, 4 measured range unloading time), the average intensity of the cargo flow entering the bunker does not change. If Ί _c, then the average intensity of the cargo traffic entering the bunker increases and when the cargo reaches the next upper level in the bunker, the conveyor is transferred to the corresponding highest speed level until the average cargo flow ₅ arrives at the bunker and coming off the belt, then equality begins again . If _{AFM I5Am} I p t ⁰ the average intensity entering the cargo tank is reduced while the conveyor It should be transferred to the (lower) level with the deceleration rate is inversely proportional to seeking equality ί ^ _B {pq - _{Chg, wherein the hopper is stopped when the discharge load level I. To do this, reduce the load to the level I1, then slow down the conveyor with a slowdown

U, -.

Chrasch ^?

I

where is the slowdown of the conveyor

V; - the speed with which the conveyor moves with equal average intensities of the cargo flows coming into the bunker and coming down from the belt;

V; ,, - the speed with which the conveyor began to move when

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unloading bunker;

^ rusk ”estimated time, EA which should be unloaded y,„ y, range 2-1;

———-- average discharge speed

this range;

5 - the volume of cargo in this range.

After braking the load in the bunker should reach the first level.

In case after this level. cargo continues to decline, the conveyor is transferred to the minimum speed ν _ο . If after that the load continues to descend, then when it reaches a certain critical level, the conveyor is stopped. After the conveyor is stopped, the rate of increase of the load level in the bunker continues to be determined. At the moment when this speed is greater than or equal to the corresponding minimum allowable speed of the conveyor, turn on the conveyor.

Block 4 (Fig. 2) is designed to perform arithmetic and logical operations, as well as determine the fill time of the bunker range and consists of an encoder 6, shapers 7 and 8 pulses, elements 9 and 10 of coincidence, registers 11 and 12 of information storage, elements 13 and 14 comparisons, of elements OR 15-17, adder 18, proportional elements 19 and 20, timer 21, element 22 for extracting the minimum signal, element 23 for extracting the maximum signal ^ of division unit 24 and register 25 for issuing information.

♦

The encoder 6 is designed to convert the positional code coming from the level sensors, and can be implemented on typical elements. The pulse shaper 7 and 8 are necessary for the formation of a signal of a certain shape and duration and can be implemented on one-shot or assembled on differentiating chains. Elements 9 and 10 matches are designed to match the signals when the unit is running. Registers 11 and 12 are designed to store information (respectively, information about the level number of the previous finding of the cargo and the number of the level of the current location

cargo). They are typical registers with a write enable input. Elements 13 and 14 comparisons are necessary for comparing signals and are typical, comparison schemes with three output states. Logic elements OR 15-17 (like elements 9 and 10 of coincidence) are necessary for matching the signals. The adder 18 is designed to calculate and store the level of the job speed. Proportional elements 19 and 20 are needed to form a signal for disconnecting the conveyor and the magnitude of the maximum acceleration, respectively, and can be performed on single-oscillators, difcepochek or multiplication elements to obtain signals proportional to the required values. Timer 21 counts the load time of the range in the bunker and is a constantly counting counter with an account blanking input. Element 22 of the selection of the minimum signal is designed to issue a job signal to disable the conveyor when receiving a signal from sensor 3 (Fig. 1) the presence of cargo at the test point.

Otherwise, at the output of the element, there is a speed reference signal generated by the adder 18. Element 23 of selection of the maximum signal is intended to provide a signal for the maximum acceleration when receiving a signal from sensor 3 (Fig. 1) the presence of load at the sixth level. Otherwise, there is an acceleration reference signal at the element output.

Block 4 works as follows.

When a signal is received from the sensor 3, indicating the presence of cargo at the first level, the latter enters the register 12 through the encoder 6. In the comparison element 14, the signals of the registers 11 and 12 are compared. At the same time, the initial setting of the register 11 corresponds to the signal size when there is a load on the first bunker level. In the case under consideration, at the output of the comparison element 14 (A = B), a supercapital appears, which, through the coincidence element 10, goes to the input A of the comparison element 13. The input of the match element also receives a signal from

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the course of the register 12. At the entrance of the comparison element 13, the signal is proportional to the presence of the load on the first level. Since in this case the signals are equal, a signal appears at the output AB of the comparison element 13, which, through the coincidence element 20, prohibits the operation of the adder 18 and the speed reference signal does not change. The initial setting of the adder is the minimum possible speed of the conveyor. It is set every time, depending on the parameters of the system under consideration, a bunker-conveyor. At the same time, from output A = B of comparison element 13, through element OR 17, timer 21 is extinguished and the filling time of the band ί I is counted. In this case, the value of register 12 is rewritten into register 11 by a signal to allow rewriting from the output of the former 7. Register 11 thus stores the value of the previous level of the load in the bunker. When filling the band with a load, it is necessary to issue a speed reference signal equal to the first level and an acceleration reference signal.

This happens as follows.

At the input of the encoder 6, a signal appears about the presence of cargo at the second level (input 2). Comparing the signals from the registers 11 and 12 at the output A <B, the comparison element 14 generates a signal that includes the adder 18 for addition. Shaper 7 generates a signal proportional to the remote control. Thus, the output of the adder 18 appears signal V = V + D1 /. The output signal from the A to the comparison element 14 through elements 16 and 17 rewrites the acceleration value obtained at the output of the division element 24, which through the output register 25 is received as an acceleration reference signal. When the load reaches the top (sixth) level at the output of the adder 18 there is a task

at the maximum speed, and through the element 23 of the selection of the maximum signal, a signal proportional to the maximum acceleration is received at the input of the output register 25.

The unloading of the bunker is as follows.

When the conveyor is transferred to the maximum speed, the bunker is unloaded and the load level drops to level 5. Thus, at output A> Comparison element 14, a signal appears that puts the adder 18 into the calculation mode. This happens because the contents of register 11 are greater than the contents of register 12. From the output of driver 7, a signal proportional to dU is received at input T of adder 18, and the signal V = V –D V _; those. speed level 'reduced. If the intensity of the incoming and outgoing traffic is equal, then at the output of At B of the comparison element 14, a signal appears that transforms the adder 18 into the summation mode through elements 9 and 16, and the signal from the imaging unit 8 yields the value of the remote control. Thus, at the output of the adder. 18 the signal V = V + D V is present and the bunker is again unloaded by one range. The acceleration in this case is proportional to the discharge time of the bunker range.

If the load reaches the level ί and continues to fall below, then when the load reaches the control point, through the proportional element 19 a task is issued to disable the conveyor.

With the proposed method of controlling the speed of the conveyor, starting-braking modes with dynamic amplification, up to 3 до static, i.e. virtually no dynamic modes, which contributes to improving the reliability of the conveyor.

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FIG. 2

Claims (2)

CONVEYOR LOADING CONTROL METHOD, based on changing the speed of the conveyor with a time delay, characterized in that, in order to improve the control accuracy and reliability of the conveyor in the work, fix the constant levels of cargo in the bunker, dividing the bunker into ranges, establish for each level of cargo an appropriate level of conveyor speed, make the transition from one speed level to another with acceleration (deceleration) proportional to the filling time (emptying) of the previous range in the bunker and translate to the maximum level of speed when the load reaches the top level with the maximum starting acceleration, and the delay in the change of speed is determined by the time § filling (emptying) the previous range in the bunker. □ about M SL 05 > one 1189756 2