SU875029A1 - Emergency disconnector responding to conveyer chain breaking or jamming - Google Patents

Description

(54) EMERGENCY-DISCONNECTION DEVICE IF THE CONTAINER CIRCUIT OR STOPPED IS CUT OFF

I

The invention relates to mining machines and can be used in the mining, construction and hoisting industries of the industry where short single-chain scraper conveyors are used. 5

A device for protecting the motor of a conveyor of a loading machine against overload, which performs the functions of disconnecting the supply voltage of a conveyor motor, is known. This protection is applied on standard PNB-EK-in and PNB-4 type loading machines and is performed using temperature relays embedded in the windings of the IJ motor.

However, in the known device, when overheating of the windings of the conveyor motor is over the permissible value, the contacts of the thermal relays open and disconnect the coil of the intermediate alarm relay. In turn, the contacts of the emergency relay relay: .with the coils of the contactors “Forward and“ Back. As a result, co-fighter motors are disconnected from the network. This protection performs shutdown functions only when the temperature of the co-veveyer engines is disturbed due to their motor technological overload. Its quick action is determined by the time of heating of the windings of electric motors, which is equal to several seconds. In the loading machine, with the stop chain conveyor in connection with its jamming by oversize rock or scraping scrapers in the channel of the conveyor, it is necessary to perform a protective shutdown in a time of approximately 0.2-0.3 s. Failure to comply with this requirement leads either to the overturning of the asynchronous motor of the conveyor, which increases the probability of its failure, or to progress. breakage of the mechanical part of the conveyor.

In connection with the heavy dynamic mode of operation of the conveyor chain in loading machines (transfer of the material to the chain itself occurs as a result of a planar nonlinear trajectory), it is not uncommon for the latter to break.

It should be noted that stopping the engine of the conveyor when the chain is broken leads to the collapse of the remaining and moving parts of the sprocket located in the conveyor feeder, jamming and seeing it with chain links, to the idle branch of the lower plate of the conveyor and to dynamic shock loads in the drive sprocket of the conveyor. As a result, progressive emergency wear and breakage of whole and moving chain links behind the break point (chain tail) and conveyor elements is observed. It is known an emergency deflection device in case of a break or locking of a conveyor chain, which contains the contactors of the conveyor and the executive body with elements of their pack; control and control unit break or locking chain. The known device provides automatic shutdown of the engine of the conveyor under emergency conditions and control of start-up time of the conveyor 2. However, due to the structure and schematic diagram and in accordance with the engine mode of the loading masking conveyor chain, this device cannot be used for emergency shutdown of the mountain loading masque conveyor. The field of use of the known device is limited to long downhole or trunk conveyors that do not have a pulsed jogging movement of the depy. This is due to the fact that the circuit is based on continuous analog conversions of the measuring / speed sensor signal by a direct loop with the corresponding formers (also analogous) parallel delays of time for switching on the relay during detuning from the starting mode and for switching off after emergency mode on the conveyor. The drawbacks of the device are also the impossibility of its use on the conveyors of loading machines, and consequently the inefficiency of emergency shutdown automation, low speed and the possibility of damage to the mechanical part of the machine when performing an emergency shutdown; The purpose of the invention is to increase the speed of an emergency shutdown when the chain of a conveyor belt of a mountain loader breaks or slides. This goal is achieved by the fact that the device is equipped with three OR circuits, two AND circuits, a NOT circuit, two - one (bratorami, differentiating link and an additional control unit installed parallel to the main one, while the main inputs and the additional control units are connected to the inputs of the first the OR circuit, the output of which is connected to the first input of the first circuit - And the second and third inputs of the first circuit AND are connected to the output of the second OR circuit, respectively, through the serially connected first one-shot and the circuit and NOT and cut the second circuit AND, the second input of which is connected to the output of the third OR circuit, and the first and second inputs of the third OR circuit are connected respectively to the output of the second AND circuit and to the output of the second OR circuit via a differentiating link, and the output of the first AND circuit is connected to the relay input via the second one-shot, and the inputs of the second OR circuit are connected to the outputs of the conveyor contactors. In addition, the control unit is made in the form of an electronic key, and a series-connected sensor controlling the movement of the circuit, the measuring signal generator, the pulse former, the NOT circuit, the integrator and the threshold element, the trunk and control inputs of the switch are connected respectively to the outputs of the integrator and the pulse former, and the output of the switch is connected to the "Integrator reset. FIG. 1 is a block diagram of the device; in fig. 2 - cyclogram of the device when the conveyor circuit is broken; in fig. 3 is a diagram of the location of the sensors on the Loader and the protective zone of each of them; in fig. 4 is a diagram of the connection of the control circuits of the contactors of the conveyor and the actuator with the electronic part of the device. The device consists of conveyor contactors and an executive body with elements of their control and object 2, including the conveyor motor and the conveyor itself. The break or latching circuit is monitored by two identical parallel blocks, each of which contains a magnetic induction sensor 3 for controlling the movement of the circuit, the former 4 of the measuring signal, the former 5 pulses, the HE 6, the integrator 7, the threshold element 8 with a predetermined threshold and the electronic key 9. The electronic key 9 is connected in parallel to the integrator 7 and receives control to switch from the output of the driver 5 pulses. (In order to read the flowchart in Fig. I, the second identical control unit for breaking or stopping the conveyor chain is indicated by the number 10). The conveyor switch-on control channel contains the OR 11 circuit, which unites both the open circuit or the locking circuit control units, the OR 12 circuit, which receives information about the Forward or Backward conveyor, the differentiating link 13 of the AND 14 circuit, which is connected to the output of the OR 12 circuit. , and the circuit OR 15, forming with the circuit AND 14 a closed ring for the passage of a logical signal. The second input of the OR circuit 15 is connected to the output of the differentiating link 13. The protection tune-out channel for the time of acceleration of the conveyor circuit contains the first one-shot 16 and the NOT 17 circuit. 20 acting on the controls "Stop of the contactors of the conveyor and the executive body 1. Circuit AND 18 at its inputs receives logical information: from the output of the circuit OR 11 about the state of the movement mode of the conveyor chain , With the output of the circuit 17, NOT the duration of the acceleration conveyor chain, from the output of the AND gate 14 on the operational inclusions conveyor. The output logic signal of the second circuit And 18 in the presence of an open circuit or locking the circuit forms a control to disable both the pipeline itself and the executive body. EA of FIG. 2 The following designations of the device operation processes, modeled as voltage signals, on a time scale are accepted: a, b, c, d, e, i, and k are respectively at the outputs (Fig. 1) of the measuring signal former 4, the pulse conditioners 5, integrator 7, circuit OR 12, differentiator 13, circuit AND 18 and the relay element 20, 4, 7 and 8, respectively, on the first, second and third inputs of circuit AND 18. The conveyor and device modes are received: 1 - machine does not immerse the mountain mass, the conveyor is stopped and there are no emergency situations; I - operational start of the conveyor either in the direction “Forward or in the direction“ Back; 111 - normal operation; IV - break or locking of the conveyor chain; V is the device actuation process; VI - time delay mode for disconnecting the contactors of the conveyor and the executive body with the appropriate alarm; VII - return of the device circuit to its original state. The time and amplitude parameters of the modes and processes in FIG. 2 have the following designations: f i is the start time of the conveyor, tj is the holding time for disconnecting the contactors of the conveyor and the executive body, is the response time of the device, and Ifor is the voltage level of impulse formation in the pulse shaper 5; Unop is the voltage level of the processing of the threshold element 8. The device operates in the corresponding modes as follows. If the loading machine does not perform loading operations, the conveyor is standing and there are no emergencies, the chain link does not pass over the magnet induction sensor controlling the movement of circuit 3 and the latter does not guarantee a pulse signal. The logical signals at the outputs of these sensors in each block are equal to zero, and therefore, are equal to zero and the signals at the outputs of the imaging unit 4 of the measuring signal and the imaging unit 5 pulses. The zero signal of the pulse driver 5 is inverted by the HE 6 circuit, and a single logical signal from the output of this circuit is fed to the input of integrator 7. The same zero signal of the pulse driver 5 is fed to the control input of the electronic switch 9 and holds the main input of the latter in the open state. The integrator 7 operates in the active mode of integration of a single logical signal. The integration time of one hundred saturation equals the slightly longer passage time of one link of the conveyor 2 past the sensitive element of the magnetic induction sensor 3 if the circuit were in a state of motion at nominal speed. It is 0.12 s. Therefore, when the conveyor 2 is stopped, from the output of the integrator 7 to the input of the threshold element 8 a maximum saturation signal is received, which is slightly larger than the predetermined threshold of the Unop threshold element 8. The threshold element 8 operates and generates on. its output is a logical unit that repeats at the output of the OR OR P circuit. Thus, both control units for open circuit or blockage of the circuit prove at the first input of the second circuit AND 18 that the circuit does not move. Since the conveyor is not on “Forward and Back, then the signals at the inputs of the second circuit OR 12 are equal, there is also a logical zero at its output and, accordingly, at the outputs of the differentiating link 13 of the circuit 14 and the one-shot 16 there is a zero logic signal. Here, the zero logic signal arriving at the third input of the circuit And 18 shows that there was no start to the movement of the conveyor chain. In the tune-up channel of protection for the acceleration (start) time of the conveyor 1, the one-shot 16 is not turned on, at its output a logical zero, which is inverted by the HE 17 circuit, and the latter supplies a logical one to the second input of the second circuit And 18. As a result, there is a discrepancy between logical single signals at the three inputs of AND circuit 18, and therefore the second one-shot 19 and the relay element 20 are not included. Emergency shutdown is absent. FIG. 2, the above-described mode and logical states of the signals are indicated by 1. At the start of the conveyor 2, the circuit is accelerated and pulse signals are generated at the output of the magnetic induction sensor 3. They are formed (rectified, amplified and limited in amplitude) in the former 4 of the measuring signal to a standard value as the conveyor circuit 2 accelerates and with a given amplitude value of the threshold for the formation of the Ifor in the former 5 pulses are converted into a rectangular pulse train. The duration of the rectangular impulse and the duration of the pause between the pulses are determined by the time span of the metal joint of the conveyor chain link and the hollow part of this link along the surface of the sensor element 3. Here during the pause moment, the motion control circuit works similarly in the integration mode. At the moments of impulses in the circuit of motion control of a circuit, a single signal from the output of the driver of the 5 pulses, which is fed to the control input of the electronic key 9, closes the last one by the main input. The integrator output 7 is connected to its input "Reset via dongle 9 and there is no integration process. At the outputs of the threshold elements and, accordingly, the scheme OR 11, the logical zero is given. However, in the initial start-up period of the conveyor 2 at the output of the integrator 7, the integrated signal reaches the predetermined threshold of the Unop threshold element 8, and as the conveyor chain accelerates to the rated speed, the maximum signal taken from the output of the integrator 7 becomes less than the predetermined threshold of the Unop threshold threshold 8 ( because the integration time decreases when the conveyor chain is accelerated). Therefore, in the initial period of movement of the conveyor chain, the control channels for its movement produce false signals at the first input, And 18 circuits. The detuning from spurious signals to the start time is reset to zero, the signal applied to the second input of the second scheme And 18 from the output of the HE 17. Here, at the moment of starting the conveyor 2, the second OR circuit 12 repeats the conveyor "Forward or Back" signal, which, with its positive differential for the start-up time t, turns on the first one-shot 16, and the second HE circuit 17 inverts it to the logical of zero. The device provides an indication of the operation of the conveyor by means of the control channel for its inclusion. The indicated indication is carried out by a logical single signal applied to the third input of the circuit AND 18 from the output of circuit 14. And here in the disjunction link 13 a positive trigger signal is differentiated in the form of a periodic pulse, which nocfynaet to the second input of the circuit OR 15 and pass through it, provides for a time diff. esentirobani coincidence of logical units at both inputs of the circuit AND 14. The self-pickup of circuit AND 14 is carried out by annular connection of its output with its second input through the circuit OR 15 through the first input. Thus, when the conveyor circuit is accelerated, even in the presence of a false signal at the first input of the second circuit And 18, there is no logical single signal at its second input, and therefore emergency shutdown is impossible. The start mode on the sequence diagram of FIG. 2 is denoted by 11. In the HopMaj bHOM mode of operation of the conveyor 2, when the circuit moves at a nominal speed, a single logical signal is restored at the second input of the second circuit AND 18, since the one-shot 16 turns itself off by selecting the specified on-time for the conveyor motor 2. At the first input of the AND 18 circuit there will be a logical zero. Since at the output of the integrator 7, integrated in the pauses of the rectangular pulse sequence, the signal does not reach the threshold value Unop specified in the threshold element 8. Thus, in normal operation of the conveyor 2, there is no coincidence of single logical signals at the inputs of the circuit And 18, and therefore emergency shutdown is not possible. In contrast to the known, the proposed device does not react to the jerky normal mode of movement of the conveyor chain, since the fixed processes are determined by discrete transformations of the pulse signals. The magnitude of the conversion increment is selected by the level of the threshold voltage with a corresponding supply of jerky normal movement of the conveyor circuit from its emergency latching mode or jerky abnormal mode at which the asynchronous conveyor motor is on the verge of tilting. A push-like abnormal mode can be traced when the conveyor pulls an oversized piece of immersed material along its chute, and this piece, turning over or brake in the chute, creates unacceptable loads close to the emergency mode of both the electric drive and the mechanical part of the conveyor. The normal mode of operation of the conveyor and the device is illustrated in the sequence diagram (Fig. 2) with the number P. When the conveyor circuit is broken or stopped (these modes are identical for the operation of the device, since in both cases the movement of the chain is stopped) the magnetic induction sensor 3 stops generating informative pulses, and therefore, rectangular pulses at the output of the pulse shaper 5 cease to form. A continuous process of integrating a single signal at the output of the integrator 7 begins. In FIG. 2 indicated mode is indicated by the number IV. It is the beginning of the process of tripping (figure V in FIG. 2). The end of tripping is determined by the coincidence of the amplitude of the signals at the output of the integrator 7 and a predetermined level of the tripping voltage Unop of the threshold

element 8. As mentioned earlier, the maximum response time of the protective disconnection after an open circuit or a chain stop is 0.12 s {Tj 0, l2 s). This time may be less if an accident occurs at the time of the process and integration. At the moment of tripping, the protective cut-off at the output of the threshold element 8 is a logical single signal, which is repeated by the OR 11 circuit, and on all three inputs of the AND 18 circuit there will be a coincidence of logical units. Therefore, a single logical signal is generated at the output of AND 18, leading to the inclusion of the one-shot 19. Thus, the device starts operating according to the time delay for shutting down the conveyor and the actuator (mode VI in Fig. 2), accompanied by appropriate signaling. The one-vibrator 19 will turn on the relay element 20 for the shut-off time delay Tj. The opening contacts of the relay element 20 located in the control circuit of the Stop of the contactors of the conveyor and the actuator 1 disconnect these contactors and the motors of the conveyor 2 and the actuator stop.

When the contactors of the conveyor I are disconnected at the output of the circuit OR 12, the logical zero is repeated, hence it is transferred to the logical zero at the first input of the circuit 14 and the circuit 18 of the third input. Kik result, on three inputs of the circuit And 18 The signals do not coincide and at its output a logical zero is obtained. However, the one-shot 19 will also include a time T, sufficient with a large margin to reliably disconnect the contactors of the conveyor and the executive 9rgan 1. This is how the device's circuit works in the time-out mode To shut off (mode VI in Fig. 2). After the time t has passed, the one-shot 19 and the relay element 20 is turned off, and since the secondary activation of the conveyor 2 "Forward or" Back after an emergency situation is not performed by the driver, the device will return to its original state (LF mode in Fig. 2).

The maximum emergency shutdown speed of the device consists of a device actuation time of 0.12 s and a shutdown time of the conveyor contactor and the relay element 20, which is not more than 0.08 s. In general, the total maximum emergency shutdown speed does not exceed 0.2 s. The use of a known device on a loading machine allows to obtain a minimum non-triggered shutdown in 2 seconds and a maximum in 6 seconds. Thus, the proposed device completely satisfies the emergency shutdown mode of the conveyor chain when it locks or breaks, allows to automate the shutdown process and eliminates possible accidents and breakdowns of the mechanical part of the machine after an open circuit of the conveyor.

The layout of the sensors on the loading machine and the zone of their protective action are shown in FIG. 3. Magnetic induction sensors 3 and 3 are installed respectively at the sprocket starter 23 and at the drive sprocket 24 and monitor the movement of the conveyor chain 21. Sensor 3 protects an open circuit in the working branch (zone A), which without the use of the device leads to the removal of the chain 21 in the sprocket the feeder 23, and the sensor 3 protects the open circuit part 21 (zone B), which, without the use of the device, removes the broken and moving part of the lower flap circuit 22 and causes shock loads from the remaining part of the chain in the drive sprocket 24. Chrome In addition, sensor 3 controls the allowable sag of the idle branches of the conveyor chain 21 (i.e. the tension of the chain 21) during normal operation of the conveyor. If the sag of the idle branch of the circuit 21 is larger than the allowable value, the signal generated by the magneto-induction sensor 3 will decrease in amplitude or completely disappear due to a large air gap, which is equivalent to a protective shutdown for the device circuit.

, FIG. 4, there are marked disconnecting contacts 25 and 26 of the relay element 20 that perform the functions of disconnecting the contactor of the conveyor "Forward (intermediate relay of contactor K and auxiliary contact of this contactor KA)," Back (intermediate relay of contactor Kg), and contactor of the executive body (intermediate relay of contactor K and the block contact of this contactor KB) - Sr, the buttons “Stop Sj and the buttons“ Start Sj, 84, Ss of the respective contactors when the machine is manually operated. Two inputs of the second circuit OR 12 are connected to the coils of the intermediate relay Ki and 4 contactors “Forward and“ Back of the conveyor. These entrances to the electronic part of the device receive information on the corresponding switching on and off of the conveyor in both directions of movement of the conveyor chain in the form of a supply voltage.

invention formula

Claims (2)

I. Emergency shutdown device in case of an open circuit or locking of the conveyor circuit, containing contactors of the conveyor and executive body with elements of their control, laziness, and a control unit for open circuit or locking the circuit, characterized in that, in order to increase the speed of emergency shutdown when the conveyor circuit is broken or locking mountain loading machine, it is equipped with three OR schemes, two AND schemes, a NOT scheme, two one-vibrators, a differentiating link and an additional control unit installed parallel to the main one, ohm the outputs of the main and additional control units are connected to the inputs of the first OR circuit, the output of which is connected to the first input of the first AND circuit, and the second to the third inputs of the first AND circuit are connected to the output of the second OR circuit, respectively, through the serially connected first one-one and NOT circuit and the second one the AND circuit, the second output of which is connected to the output of the third OR circuit, and the first and second inputs of the third OR circuit, respectively, are connected to the output of the second AND circuit and to the output of the second OR circuit through a differentiating link, m output of the first AND circuit is connected to the input of the relay via a second monostable multivibrator and a second input of OR gate connected to outputs of contactors conveyor. 2. The device according to claim 1, characterized in that the control unit is made in the form of an electronic key and a series-connected motion control sensor, a measuring signal generator, a pulse generator, a NOT circuit, an integrator and a threshold element, the main and control inputs of the key are connected respectively, with the outputs of the integrator and pulse generator, and the output of the key is connected to the input “Reset the integrator. Sources of information taken into account in the examination of 1, Gram G. A. and others. Shakhtna loading machine PNB-4. M., “Nedra, 1974 p. 65-70. 2. Albyev N. M. Automation of production in coal mines. M., "Nedra, p. 50-52. f s  J