Control circuit and control system of coal conveying roller screen

Abstract

The invention relates to a control circuit and a control system of a coal conveying roller screen, and relates to the technical field of coal conveying roller screen control. The control circuit comprises a first control loop, a second control loop, a third control loop and a fourth control loop, the first control loop is used for controlling all rollers of the roller screen to start one by one, and stopping all the started rollers if any roller fails to start in the starting process; the second control loop is used for monitoring signals indicating that all the rolling shafts are started and triggering the decentralized control system to start the coal feeding side belt, and when the signals indicating that all the rolling shafts are started disappear, the decentralized control system stops running the coal feeding side belt; the third control loop is used for monitoring whether the contactor corresponding to any group of adjacent rolling shafts fails or not; the fourth control loop is used for responding to fault signals, stopping the roller screen and giving an alarm, and the fault signals comprise a signal indicating that the contactors of any group of adjacent rollers fail and a coal blockage signal. The control circuit can improve the safety of the roller screen and reduce the risk of coal blockage.

Description

Technical Field

[0001] The present disclosure relates to the technical field of coal conveying roller screen control, and in particular, to a control circuit and control system of a coal conveying roller screen. Background Art

[0002] The coal conveyor roller screen is a key device in the coal conveying system of a power plant, responsible for the preliminary screening of the coal. It consists of a drive device, rollers, screen plates and screen boxes. When working, the motor drives the rollers to rotate, and the screen plates cut the coal and achieve graded screening. The coal conveyor roller screen is usually installed behind the belt on the coal side. It is remotely controlled and monitored by a distributed control system (DCS).

[0003] The coal conveyor roller screen control technology has the following major problems. 1. Inaccurate judgment of the operating status: The distributed control system only relies on the status of roller No. 1 to judge the operation of the entire coal conveyor roller screen. When roller No. 1 trips, the entire coal conveyor roller screen and the incoming coal side belt will be shut down, even if the other rollers are normal, causing unnecessary coal blockage. 2. Imperfect fault interlock protection: Only when the power switches of two adjacent rollers trip at the same time will the overall shutdown be triggered. In other fault situations, the distributed control system cannot detect and handle them in a timely and accurate manner, resulting in the coal conveyor roller screen being unable to operate normally and the incoming coal side belt continuing to work, increasing the risk of coal blockage.

[0004] In short, the coal conveying roller screen control technology has the defects of inaccurate operation status judgment and imperfect fault interlocking protection, which leads to low operation efficiency of the power plant coal conveying system and easy coal blockage. Summary of the invention

[0005] In order to solve the above problems, the present invention provides a control circuit and a control system for a coal conveying roller screen.

[0006] In a first aspect, the present disclosure provides a control circuit for a coal conveying roller screen, comprising: a first control loop, a second control loop, a third control loop, and a fourth control loop; The first control loop is used to control all rollers of the roller screen to start one by one, and if any roller fails to start during the starting process, all the started rollers will be stopped; The second control loop is used to monitor whether all rollers have been started and trigger the distributed control system to start the coal-incoming side belt, and to monitor whether the roller screen has stopped operating and trigger the distributed control system to stop the coal-incoming side belt; The third control loop is used to monitor whether the contactors corresponding to any group of adjacent rollers are faulty; The fourth control loop is used to stop the roller screen and alarm in response to a fault signal, wherein the fault signal includes a signal that the contactors of any group of adjacent rollers are faulty.

[0007] Optionally, the second control loop includes a first subcircuit and a second subcircuit connected in series between a power supply and a ground line; The first subcircuit includes first normally open contacts of a plurality of contactors and a first normally open contact of a first relay, the first normally open contacts of all contactors are connected in series and in parallel with the first normally open contact of the first relay, and each contactor controls the start and stop of a roller; The second sub-circuit includes a coil of a first relay; When the first normally open contacts of all contactors are closed, the coil of the first relay is energized, and the second normally open contacts of the closed first relay trigger the distributed control system to start the coal-incoming side belt.

[0008] Optionally, the second sub-circuit includes a first normally closed contact of the second relay and a normally closed contact of the third relay, and the first normally closed contact of the second relay, the normally closed contact of the third relay and the coil of the first relay are connected in series; The second relay is used to control the roller screen to stop operating; The third relay is used to respond to the fault signal and act; When the first normally closed contact of the second relay is disconnected and / or the normally closed contact of the third relay is disconnected, the coil of the first relay is de-energized and the second normally open contact of the first relay is disconnected, triggering the distributed control system to shut down the coal-side belt.

[0009] Optionally, the first control loop includes a third subcircuit and a fourth subcircuit, and the third subcircuit is arranged between the power supply and the ground line; The third subcircuit includes a normally closed contact of a first time relay, a roller screen start button, a second normally closed contact of a second relay, a first normally closed contact of a second time relay and a coil of a second time relay connected in series, and the coil of the second time relay is connected in parallel with the fourth subcircuit; The fourth subcircuit includes a fifth subcircuit and a sixth subcircuit connected in parallel, the fifth subcircuit includes a seventh subcircuit, a delayed disconnection normally closed contact of a third time relay, and a coil of the third time relay connected in series, the seventh subcircuit includes a first normally open contact of the third time relay and a delayed closing normally open contact of the fourth time relay connected in parallel, and the sixth subcircuit includes a delayed disconnection normally closed contact of the fourth time relay, a normally closed contact of the third time relay, and a coil of the fourth time relay connected in series; The second time relay is used to monitor whether the start of the roller screen has timed out. If all rollers fail to start successfully within the preset time, the second time relay will control the roller screen to stop and start; When the roller screen start button is closed, the fourth subcircuit is turned on, the coil of the second time relay is energized, and the fourth subcircuit is de-energized after the first normally closed contact of the second time relay is disconnected with a delay; The fourth sub-circuit is used to alternately energize the coil of the fourth time relay and the coil of the third time relay to generate a control signal for starting all the rolling rollers one by one.

[0010] Optionally, the third sub-circuit further comprises a normally closed contact of a first relay, and the normally closed contact of the first relay is connected in series with the remaining elements of the third sub-circuit; When the coil of the first relay is energized, the normally closed contact of the first relay is opened, and the first control circuit is de-energized.

[0011] Optionally, the first control loop includes a third normally closed contact of a second relay connected in series between a first node and the ground wire and an eighth subcircuit, the first node being a node between the normally closed contact of the first time relay and the roller screen start button; The eighth subcircuit includes a ninth subcircuit and a plurality of roller start circuits connected in parallel, and all the roller start circuits are connected in parallel; The ninth subcircuit includes a tenth subcircuit and an eleventh subcircuit connected in parallel, the tenth subcircuit includes a second normally open contact of a third time relay and a coil of a fourth relay connected in series, and the eleventh subcircuit includes a normally open contact of a fourth time relay and a coil of a fifth relay connected in series; There are a plurality of fourth relays, each of which is used to control the start of an even-numbered roller; there are a plurality of fifth relays, each of which is used to control the start of an odd-numbered roller; Each roller start circuit is used to control the start of a roller, and each roller start circuit includes a normally open contact of the corresponding fourth relay or fifth relay, a coil of the contactor corresponding to the roller, a second normally open contact of the contactor corresponding to the roller, and a third normally open contact of the contactor corresponding to the next roller; The eighth subcircuit is used to control all rollers to start in sequence according to the order of roller numbers. When the fourth subcircuit is energized, the coil of the fourth time relay and the coil of the third time relay are alternately energized, the coil of the fourth relay and the coil of the fifth relay are alternately energized, the normally open contact of the fourth relay and the normally open contact of the fifth relay are alternately closed, the contactors of all rollers are energized in sequence according to the order of corresponding roller numbers, the rollers are started in sequence according to the order of roller numbers, and the rollers are numbered in sequence from one end to the other according to their physical installation positions in the roller screen; The second relay is used to control the roller screen to stop operating. When the third normally closed contact of the second relay is disconnected, the eighth sub-circuit is powered off, the contactors of all rollers are powered off, and all rollers are shut down.

[0012] Optionally, the first control loop further includes a second normally closed contact of a second time relay, a third normally closed contact of the second relay, a second normally closed contact of the second time relay, and the eighth sub-circuit connected in series; The second time relay is used to stop all started rollers if any roller fails to start during the starting process; When the second normally closed contact of the second time relay is disconnected with a delay, the eighth sub-circuit is de-energized, the contactors of all rollers are de-energized, and all rollers are stopped.

[0013] Optionally, the third control loop includes a twelfth sub-circuit, a thirteenth sub-circuit and a coil of a sixth relay connected in series between the first node and the ground line; The twelfth sub-circuit includes the third normally open contact of the first relay and the first normally open contact of the sixth relay connected in parallel; The thirteenth sub-circuit includes a plurality of branches, each branch includes normally closed contacts of two contactors connected in series, and the two contactors are contactors corresponding to adjacent rollers; When the contactors corresponding to any group of adjacent rollers fail, the normally closed contacts of the contactors corresponding to any group of adjacent rollers are closed, the coil of the sixth relay is energized, the first normally open contact of the sixth relay is closed, and the fourth control circuit is linked.

[0014] Optionally, the fourth control loop includes a linked fourteenth sub-circuit and a fifteenth sub-circuit; The fourteenth sub-circuit includes a second normally open contact of a sixth relay and a coil of a third relay connected in series between the power supply and the ground line; The fifteenth sub-circuit includes a normally open contact and an indicator light of a third relay connected in series between the power supply and the ground line, and a normally open contact and a coil of a first time relay of a seventh relay connected in series between the power supply and the ground line, and the normally open contact of the third relay is connected in parallel with the normally open contact of the seventh relay; When the second normally open contact of the sixth relay is closed, the coil of the third relay is energized, the normally open contact of the third relay is closed, and the normally closed contact of the third relay is opened; When the normally open contact of the third relay is closed and / or the normally open contact of the seventh relay is closed, the indicator light is on and the coil of the first time relay is energized, the normally closed contact of the first time relay is disconnected with a time delay, the first control circuit is powered off, and all rollers stop operating; When the belt on the coal-incoming side is blocked by coal, the normally open contact of the seventh relay is closed.

[0015] In a second aspect, the present disclosure further provides a control system for a coal conveying roller screen, comprising: a coal conveying roller screen and a control circuit of the coal conveying roller screen as described in any one of the first aspects, wherein the control circuit is used to control the coal conveying roller screen.

[0016] Through the above technical scheme, in the process of the first control loop controlling the start of all rollers of the roller screen, if the second control loop detects that all rollers have been started, the signal is forwarded to the distributed control system, and the distributed control system starts the coal-incoming side belt. Therefore, the distributed control system can accurately judge the operation of the roller screen, so that the coal-incoming side belt can be controlled in time. When the roller screen is running, if the third control loop detects that the contactors corresponding to the adjacent rollers are all faulty, the fourth control loop is triggered. The fourth control loop can respond to the coal blocking signal and the signal that the contactors of one of the adjacent roller pairs are all faulty, control the roller screen to stop and alarm. The third control loop detects that the roller screen is stopped, triggering the distributed control system to stop the coal-incoming side belt. Therefore, the control circuit can monitor and handle the situation where the contactors corresponding to the adjacent rollers are all faulty, and improve the fault interlocking protection. Therefore, the above technical scheme can improve the efficiency of the coal transportation system of the power plant and reduce the risk of coal blocking.

[0017] Other features and advantages of the present disclosure will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings are used to provide a further understanding of the present disclosure and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present disclosure but do not constitute a limitation of the present disclosure. In the accompanying drawings: Figure 1 is a structural diagram of a control circuit of a coal conveying roller screen according to an exemplary embodiment; Figure 2 is a structural diagram of a second control loop according to an exemplary embodiment; Figure 3 is a structural diagram of a first control loop according to an exemplary embodiment; Figure 4 is a structural diagram of a first control loop according to another exemplary embodiment; Figure 5 is a structural diagram of a third control loop according to an exemplary embodiment; Figure 6 is a structural diagram of a fourth control loop according to an exemplary embodiment.

[0019] Description of Reference Numerals The first control loop 10, the second control loop 20, the third control loop 30, the fourth control loop 40, the distributed control system 50, the first normally open contact (101) 101 of the plurality of contactors, the normally closed contact 102 of the contactors corresponding to the adjacent rollers, the normally closed contact 1i2 of the contactors corresponding to a single group of adjacent rollers, the coil 1i0 of the contactor corresponding to the single roller, the second normally open contact 1i3 of the contactor corresponding to the single roller, the third normally open contact 1j4 of the contactor corresponding to the next roller, the coil 210 of the first relay, the first relay the first normally open contact 211 of the first relay, the second normally open contact 212 of the first relay, the third normally open contact 213 of the first relay, the normally closed contact 214 of the first relay, the first normally closed contact 221 of the second relay, the second normally closed contact 222 of the second relay, the third normally closed contact 223 of the second relay, the coil 230 of the third relay, the normally open contact 231 of the third relay, the normally closed contact 232 of the third relay, the coil 240 of the fourth relay, the coil 250 of the fifth relay, the coil 251 of the fourth relay or the fifth relay Normally open contact 245, coil 260 of the sixth relay, first normally open contact 261 of the sixth relay, second normally open contact 262 of the sixth relay, normally open contact 271 of the seventh relay, coil 310 of the first time relay, normally closed contact 311 of the first time relay, coil 320 of the second time relay, first normally closed contact 321 of the second time relay, second normally closed contact 322 of the second time relay, coil 330 of the third time relay, first normally open contact 331 of the third time relay, and second normally closed contact 332 of the third time relay. The second normally open contact 332 of the relay, the normally closed contact 333 of the third time relay, the delayed opening normally closed contact 334 of the third time relay, the coil 340 of the fourth time relay, the normally open contact 341 of the fourth time relay, the delayed closing normally open contact 342 of the fourth time relay, the delayed opening normally closed contact 343 of the fourth time relay, the roller screen start button 400, multiple roller start circuits 500, a single roller start circuit 5i0, an indicator light 600, a power supply 700, a ground wire 800, and a first node 900. DETAILED DESCRIPTION

[0020] The specific implementation of the present disclosure is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described herein is only used to illustrate and explain the present disclosure, and is not used to limit the present disclosure.

[0021] Figure 1 FIG. 1 is a structural diagram of a control circuit of a coal conveying roller screen according to an exemplary embodiment. Figure 1 The control circuit of the coal conveying roller screen shown includes: a first control loop 10, a second control loop 20, a third control loop 30 and a fourth control loop 40; the first control loop 10 is used to control all rollers of the roller screen to start one by one, and if any roller fails to start during the starting process, all started rollers will be shut down; the second control loop 20 is used to monitor whether all rollers have been started and trigger the distributed control system 50 to start the coal-incoming side belt, and to monitor the roller screen to stop and trigger the distributed control system 50 to shut down the coal-incoming side belt; the third control loop 30 is used to monitor whether the contactors corresponding to any group of adjacent rollers are faulty; the fourth control loop 40 is used to shut down the roller screen and alarm in response to a fault signal, and the fault signal includes a signal that the contactors of any group of adjacent rollers are all faulty.

[0022] Here, the first control loop 10, the second control loop 20, the third control loop 30 and the fourth control loop 40 are all connected in parallel between the power supply 700 and the ground wire 800. The interaction with the distributed control system 50 is realized through the second control loop 20. Contactor failure refers to contactor power failure caused by damage to the contactor coil, loose circuit wiring, poor contact of contacts, etc.

[0023] It should be understood that the main function of the roller screen is to screen the coal and separate coal of different particle sizes. If the roller screen stops operating, but the coal-incoming belt in front of the roller screen is still running, the unscreened coal will directly enter the belt conveyor system, causing large pieces of coal to block the belt. Therefore, in order to avoid the above-mentioned coal blockage, when the roller screen stops operating, the decentralized system will control the coal-incoming belt to stop operating. In addition, due to the process characteristics of the roller screen, the roller screen can still work normally and the coal-incoming belt can continue to load coal in the following situations. (1) After a single roller stops operating due to a fault and the remaining rollers are working normally. (2) After multiple non-adjacent rollers stop operating due to a fault and the remaining rollers are working normally.

[0024] The above control circuit can perform the following control process. The first control loop 10 controls all rollers of the roller screen to start one by one. During the startup process, if any roller fails to start, the first control loop 10 will stop all the started rollers. If all rollers are successfully started, the first control loop 10 triggers the second control loop 20. The second control loop 20 detects the trigger signal of the first control loop 10, that is, the second control loop 20 detects that all rollers have been successfully started, and the second control loop 20 triggers the distributed control system 50. The distributed control system 50 detects the trigger signal of the second control loop 20, that is, the distributed control system 50 detects that the roller screen is working normally, and the distributed control system 50 will start the coal side belt to screen and transport coal. In the normal operation of the roller screen, if the contactors corresponding to any group of adjacent rollers are powered off due to a fault, the third control loop 30 detects this situation, and the third control loop 30 triggers the fourth control loop 40. The fourth control loop 40 detects the trigger signal of the third control loop 30, that is, the fourth control loop 40 detects the roller screen failure, and the fourth control loop 40 will stop the roller screen and alarm. In addition, the fourth control loop 40 will trigger the second control loop 20. The second control loop 20 detects the trigger signal sent by the fourth control loop 40, and the second control loop 20 detects the roller screen failure. The second control loop 20 will stop triggering the distributed control system 50. The distributed control system 50 does not detect the normal operation of the roller screen. The distributed control system 50 will stop the coal side belt.

[0025] Through the above technical scheme, in the process of the first control loop 10 controlling the start of all rollers of the roller screen, if the second control loop 20 detects that all rollers have been started, the signal is forwarded to the distributed control system 50, and the distributed control system 50 starts the coal side belt. Therefore, the distributed control system 50 can accurately judge the operation of the roller screen, so that the coal side belt can be controlled in time. When the roller screen is running, if the third control loop 30 detects that the contactors corresponding to the adjacent rollers are all faulty, the fourth control loop 40 is triggered. The fourth control loop 40 can respond to the coal blocking signal and the signal that the contactors of one of the adjacent roller pairs are all faulty, control the roller screen to stop and alarm. The third control loop 30 detects that the roller screen is stopped, triggering the distributed control system 50 to stop the coal side belt. Therefore, the control circuit can monitor and handle the situation where the contactors corresponding to the adjacent rollers are all faulty, and improve the fault interlocking protection. Therefore, the above technical scheme can improve the efficiency of the coal transportation system of the power plant and reduce the risk of coal blocking.

[0026] Figure 2 is a structural diagram of the second control loop 20 according to an exemplary embodiment. Figure 2As shown, in one embodiment, the second control loop 20 includes a first subcircuit and a second subcircuit connected in series between a power supply 700 and a ground wire 800; the first subcircuit includes a first normally open contact 101 of a plurality of contactors and a first normally open contact 211 of a first relay, the first normally open contacts 101 of all contactors are connected in series and in parallel with the first normally open contact 211 of the first relay, and each contactor controls the start and stop of a roller; the second subcircuit includes a coil 210 of the first relay; when the first normally open contacts 101 of all contactors are closed, the coil 210 of the first relay is energized, and the second normally open contact 212 of the closed first relay triggers the distributed control system 50 to start the coal-incoming side belt.

[0027] The second control loop 20 can implement the following control process.

[0028] (1) The first control loop 10 controls the start of all rollers, that is, controls the coils of the contactors of all rollers to be energized. When the coils of the contactors of all rollers are energized, the first normally open contacts 101 of all contactors are closed, so that the coil 210 of the first relay is energized. After the coil 210 of the first relay is energized, the first normally open contact 211 and the second normally open contact of the first relay are both closed. After the first normally open contact 211 of the first relay is closed, the coil 210 of the first relay is continuously energized. After the second normally open contact 212 of the first relay is closed, the distributed control system 50 detects that the roller screen is working normally, so the distributed control system 50 starts the coal-incoming side belt to screen and transport coal.

[0029] (2) If any roller fails to start, the coil 1i0 of the contactor corresponding to the roller is de-energized. The first normally open contact 101 of the contactor cannot be closed, so the coil 210 of the first relay is de-energized. The second normally open contact 212 of the first relay cannot be closed, so the distributed system trigger signal cannot be sent. If the distributed system does not receive the trigger signal, it is determined that the roller screen is not working properly and the coal side belt will not be started.

[0030] (3) When all rollers have been started, that is, during the normal operation of the roller screen, if the contactor corresponding to a single or non-adjacent roller is powered off due to a fault, the first control circuit 10 will not operate. The specific reasons are as follows. The first normally open contact 211 of the first relay is closed and forms a loop with the coil 210 of the first relay. The coil 210 of the first relay is continuously energized, and the first relay is in a self-maintaining state. Therefore, even if the first normally open contact 101 of the contactor corresponding to a single or non-adjacent roller is disconnected, it will not cause the coil 210 of the first relay to be powered off. At this time, the distributed control system 50 will still determine that the roller screen is operating normally.

[0031] Therefore, through the second control loop 20, the successful start of all rollers can be transmitted to the distributed control system 50 as a signal that the roller screen is working properly, that is, the signal that the roller screen is working properly can be accurately transmitted to the distributed control system 50. Compared with the related art, only the successful start of roller No. 1 is transmitted to the distributed control system 50 as a signal that the roller screen is working properly, and the second control loop 20 has a higher accuracy in judging the normal operation of the roller screen.

[0032] In addition, through the second control loop 20, when the contactor of a single roller is powered off or the contactors of non-adjacent rollers are powered off, the signal that the roller screen is working properly will not be stopped from being sent to the distributed control system 50. Compared with the related art, the signal that the roller screen is working properly is interrupted when the No. 1 roller stops operating, and the second control loop 20 has a higher accuracy in judging the normal operation of the roller screen.

[0033] Therefore, the second control loop 20 can more accurately determine whether the roller screen is working normally, so that the distributed control system 50 can correctly control the operation of the power plant coal transportation system, improve the efficiency of the power plant coal transportation system, and reduce the risk of coal blockage.

[0034] like Figure 2 As shown, in one embodiment, the second subcircuit includes a first normally closed contact 221 of a second relay and a normally closed contact 232 of a third relay, and the first normally closed contact 221 of the second relay, the normally closed contact 232 of the third relay and the coil 210 of the first relay are connected in series; the second relay is used to control the shutdown of the roller screen; the third relay is used to respond to the fault signal and act; when the first normally closed contact 221 of the second relay is disconnected and / or the normally closed contact 232 of the third relay is disconnected, the coil 210 of the first relay is de-energized, and the second normally open contact 212 of the first relay is disconnected, triggering the distributed control system 50 to shut down the coal-side belt.

[0035] The second relay and the third relay in the second control loop 20 can interrupt the self-holding state of the first relay, and the specific process is as follows.

[0036] (1) When the roller screen needs to be stopped, the coil of the second relay is energized. The first normally closed contact 221 of the second relay is disconnected, so the coil 210 of the first relay is de-energized. The second normally open contact 212 of the first relay is disconnected, interrupting the signal indicating that the roller screen is working normally, which is sent to the distributed control system 50. The distributed control system 50 therefore stops the coal-side belt.

[0037] (2) In the event of a failure of the roller screen, the coil 230 of the third relay is energized. The normally closed contact 232 of the third relay is disconnected, so the coil 210 of the first relay is de-energized. The second normally open contact 212 of the first relay is disconnected, interrupting the signal sent to the distributed control system 50 indicating that the roller screen is operating normally. The distributed control system 50 therefore stops the coal-side belt.

[0038] The second control loop 20 can immediately respond to the signal of the roller screen stop and failure, and convey the status of the roller screen to the distributed control system 50. Compared with the related art, the distributed control system 50 is triggered only when the No. 1 shaft stops operating. The second control loop 20 can improve the response speed of the distributed control system 50 to the roller screen stop and failure status, thereby improving the efficiency of the power plant coal transportation system and reducing the risk of coal blockage.

[0039] Figure 3 is a structural diagram of the first control loop 10 according to an exemplary embodiment. Figure 3 As shown, in one embodiment, the first control loop 10 includes a third subcircuit and a fourth subcircuit, and the third subcircuit is arranged between the power supply 700 and the ground wire 800; the third subcircuit includes the normally closed contact 311 of the first time relay, the roller screen start button 400, the second normally closed contact 222 of the second relay, the first normally closed contact 321 of the second time relay and the coil 320 of the second time relay in series, and the coil 320 of the second time relay is connected in parallel with the fourth subcircuit; the fourth subcircuit includes the fifth subcircuit and the sixth subcircuit in parallel, and the fifth subcircuit includes the seventh subcircuit connected in series, the delayed disconnection normally closed contact 334 of the third time relay and the coil 330 of the third time relay, and the seventh subcircuit includes the first normally open contact 331 of the third time relay and the sixth subcircuit in parallel. The delayed closing normally open contact 342 of the fourth time relay, the sixth sub-circuit includes the delayed opening normally closed contact 343 of the fourth time relay, the normally closed contact 333 of the third time relay and the coil 340 of the fourth time relay connected in series; the second time relay is used to monitor whether the start of the roller screen is overtime. If all rollers fail to start successfully within the preset time, the second time relay will control the roller screen to stop and start; when the roller screen start button 400 is closed, the fourth sub-circuit is turned on, the coil 320 of the second time relay is energized, and the first normally closed contact 321 of the second time relay is delayed and disconnected before the fourth sub-circuit is powered off; the fourth sub-circuit is used to alternately energize the coil 340 of the fourth time relay and the coil 330 of the third time relay to generate a control signal to start all rolling rollers one by one.

[0040] The first control loop 10 can implement the following control process.

[0041] The user presses the roller screen start button 400, and the roller screen start button 400 is closed. Since all the contacts in the third sub-circuit are normally closed contacts, when the roller screen start button 400 is closed, the third sub-circuit is turned on, and the coil of the second time relay is energized. The first normally closed contact 321 of the second time relay is a delayed disconnect normally closed contact. Therefore, in the first delay timing of the second time relay, the third sub-circuit is turned on; when the delay timing ends, the third sub-circuit is powered off. All rollers of the roller screen need to be started in the first delay timing, otherwise the start will be terminated. After the third sub-circuit is turned on, since the contacts in the sixth sub-circuit are all normally closed contacts, the sixth sub-circuit is also turned on. So in the first delay timing, the following process of alternating the electrification of the coil 330 of the third time relay and the coil 340 of the fourth time relay is performed.

[0042] The coil 340 of the fourth time relay in the sixth subcircuit is energized. After the second delay timing of the fourth time relay ends: the delayed disconnection normally closed contact 343 of the fourth time relay is disconnected, and the coil 340 of the fourth time relay is de-energized; at the same time, the delayed closing normally open contact 342 of the fourth time relay is closed, and the coil 330 of the third time relay is energized. After the coil 340 of the fourth time relay is de-energized, the delayed disconnection normally closed contact 343 of the fourth time relay is instantaneously closed. After the coil 330 of the third time relay is energized, the normally closed contact 333 of the third time relay is instantaneously disconnected, the first normally open contact 331 of the third time relay is instantaneously closed, and the third time relay remains energized. After the third delay timing of the third time relay ends, the delayed disconnection normally closed contact 334 of the third time relay is disconnected, and the coil 330 of the third time relay is de-energized. The first normally open contact 331 of the third time relay is instantaneously disconnected, the normally closed contact 333 of the third time relay is instantaneously closed, and the coil 340 of the fourth time relay is energized. The above process is repeated. After the first delay timing ends, the first normally closed contact 321 of the second time relay is disconnected, and the above process ends. The coil 330 of the third time relay and the coil 340 of the fourth time relay are both de-energized.

[0043] The first control loop 10 generates a control signal for starting all rolling rollers one by one by alternately electrifying the coil 340 of the fourth time relay and the coil 330 of the third time relay. Compared with the related art, which uses only one time relay to generate a control signal for starting all rolling rollers one by one, the first control loop 10 is more reliable and can improve the reliability and safety of the roller screen start-up.

[0044] like Figure 3As shown, in one embodiment, the third sub-circuit also includes a normally closed contact 214 of a first relay, and the normally closed contact 214 of the first relay is connected in series with the remaining elements of the third sub-circuit; when the coil 210 of the first relay is energized, the normally closed contact 214 of the first relay is disconnected, and the first control loop 10 is de-energized.

[0045] The following control process can be realized by the first control loop 10. When the roller screen is working normally, the coil 210 of the first relay is energized, the normally closed contact 214 of the first relay is disconnected, and the first control loop 10 is powered off. That is, when the roller screen is working normally, the control of the roller screen startup is stopped, thereby perfecting the control logic of the roller screen.

[0046] Figure 4 is a structural diagram of the first control loop 10 according to another exemplary embodiment. Figure 4As shown, in one embodiment, the first control loop 10 includes a third normally closed contact 223 of a second relay connected in series between a first node 900 and the ground wire 800 and an eighth subcircuit, the first node 900 being a node between the normally closed contact 311 of the first time relay and the roller screen start button 400; the eighth subcircuit includes a ninth subcircuit connected in parallel and a plurality of roller start circuits 500, all of which are connected in parallel; the ninth subcircuit includes a tenth subcircuit and an eleventh subcircuit connected in parallel, the tenth subcircuit includes a second normally open contact 332 of a third time relay connected in series and a coil 240 of a fourth relay, the eleventh subcircuit includes a normally open contact 341 of a fourth time relay connected in series and a coil 250 of a fifth relay; there are a plurality of fourth relays, each of which is used to control the start of an even-numbered roller, and there are a plurality of fifth relays, each of which is used to control the start of an odd-numbered roller; each roller start circuit 5i0 is used to control the start of a roller, and each roller start circuit 5i0 includes a corresponding The fourth relay or the fifth relay of the normally open contact 245, the coil 1i0 of the contactor corresponding to the roller, the second normally open contact 1i3 of the contactor corresponding to the roller, and the third normally open contact 1j4 of the contactor corresponding to the next roller; the eighth sub-circuit is used to control all rollers to start in sequence according to the order of roller numbers. When the fourth sub-circuit is energized, the coil 340 of the fourth time relay and the coil 330 of the third time relay are alternately energized, and the coil 240 of the fourth relay and the coil 250 of the fifth relay are alternately energized. energized, the normally open contact 245 of the fourth relay is alternately closed with the normally open contact 245 of the fifth relay, the contactors of all rollers are energized in sequence according to the numbering order of the corresponding rollers, the rollers are started in sequence according to the roller numbering order, and the rollers are numbered in sequence from one end to the other according to their physical installation positions in the roller screen; the second relay is used to control the shutdown of the roller screen, and when the third normally closed contact 223 of the second relay is disconnected, the eighth sub-circuit is de-energized, the contactors of all rollers are de-energized, and all rollers are shut down.

[0047] The following control process can be implemented through the first control loop 10 .

[0048] In the first delay timing, the coil 330 of the third time relay and the coil 340 of the fourth time relay are alternately energized, and at the same time, the second normally open contact 332 of the third time relay and the normally open contact 341 of the fourth time relay are alternately closed. The coil 240 of the fourth relay and the coil 250 of the fifth relay are alternately energized, and at the same time, the normally open contact 245 of the fourth relay and the normally open contact 245 of the fifth relay are alternately closed. There are multiple fourth relays, and the normally open contact 245 of each fourth relay is used to control the start of an even-numbered roller. There are multiple fifth relays, and the normally open contact 245 of each fifth relay is used to control the start of an odd-numbered roller. In this way, the rollers can be controlled to start in sequence. The control process of a single roller start circuit is as follows.

[0049] The next roller has started, which means that the third normally open contact of its corresponding contactor is closed. When the normally open contact of the fourth / fifth relay corresponding to the roller to be started is closed, the coil 1i0 of the contactor corresponding to the roller to be started is energized. The second normally open contact of the contactor is closed, so that the coil of the contactor remains energized, and the roller is started. At the same time, the third normally open contact of the contactor is closed to assist the previous roller in starting.

[0050] The first control loop 10 assists the roller start-up through a plurality of fourth relays and fifth relays, thereby improving the reliability and stability of the roller screen start-up.

[0051] like Figure 4 As shown, in one embodiment, the first control circuit 10 also includes a second normally closed contact 322 of a second time relay, a third normally closed contact 223 of the second relay, a second normally closed contact 322 of the second time relay and the eighth sub-circuit are connected in series; the second time relay is used to shut down all started rollers if any roller fails to start during the startup process; when the second normally closed contact 322 of the second time relay is disconnected with a delay, the eighth sub-circuit is powered off, the contactors of all rollers are powered off, and all rollers are shut down.

[0052] The first control loop 10 can implement the following control process.

[0053] (1) During the first delay timing, all rollers are successfully started. Then the normally closed contact 214 of the first relay is disconnected, and the coil 320 of the second time relay is de-energized. The second normally closed contact 322 of the second time relay remains closed, and the coils of the contactors of all rollers also remain energized.

[0054] (2) During the first delay timing, if any roller fails to start successfully, the normally closed contact 214 of the first relay remains closed, and the coil 320 of the second time relay remains energized. When the first delay timing ends, the second normally closed contact 322 of the second time relay opens, and the coils of the contactors of all rollers are de-energized. Therefore, all rollers are stopped.

[0055] Through the second normally closed contact 322 of the second time relay, it can be achieved that if all rollers fail to start successfully within a certain time, all rollers are controlled to stop running. Thus, the first control loop 10 can improve the safety and reliability of the roller screen startup process.

[0056] Figure 5 is a structural diagram of the third control loop 30 according to an exemplary embodiment. Figure 5 As shown, in one embodiment, the third control loop 30 includes a twelfth sub-circuit, a thirteenth sub-circuit and a coil 260 of a sixth relay connected in series between the first node 900 and the ground line 800; the twelfth sub-circuit includes a third normally open contact 213 of the first relay and a first normally open contact 261 of the sixth relay connected in parallel; the thirteenth sub-circuit includes a plurality of branches, each branch includes normally closed contacts of two contactors connected in series, and the two contactors are contactors corresponding to adjacent rollers; in the event that the contactors corresponding to any group of adjacent rollers fail, the normally closed contacts 102 of the contactors corresponding to any group of adjacent rollers are closed, the coil 260 of the sixth relay is energized, and the first normally open contact 261 of the sixth relay is closed, thereby linking the fourth control loop 40.

[0057] The third control loop 30 can be implemented during the operation of the roller screen. If the contactors corresponding to any group of adjacent rollers are powered off due to a fault, the fourth control loop 40 is triggered. The specific control process is as follows. When all roller contactors are fault-free, the normally closed contacts of all contactors are in an open state. And the coil 210 of the first relay remains energized, and the third normally open contact 213 of the first relay remains closed. If the roller contactor is powered off due to a fault, the normally closed contact of the contactor returns to a closed state. The normally closed contacts 102 of the contactors corresponding to any group of adjacent rollers are all restored to closure. The coil 260 of the sixth relay is energized, and the first normally open contact 261 of the sixth relay is closed, so that the coil 260 of the sixth relay remains energized, and the fourth control loop can be continuously triggered.

[0058] Through the third control loop 30, it is possible to monitor whether the contactor corresponding to any group of adjacent rollers is faulty. Compared with the related art, which only monitors whether the power supply 700 switch corresponding to any group of adjacent rollers is faulty, the third control loop 30 also monitors the state of the contactor, which can improve the safety of the roller screen operation.

[0059] Figure 6 is a structural diagram of the fourth control loop 40 according to an exemplary embodiment. Figure 6 As shown, in one embodiment, the fourth control loop 40 includes a linked fourteenth sub-circuit and a fifteenth sub-circuit; the fourteenth sub-circuit includes the second normally open contact 262 of the sixth relay and the coil 230 of the third relay connected in series between the power supply 700 and the ground line 800; the fifteenth sub-circuit includes the normally open contact 231 of the third relay and the indicator light 600 connected in series between the power supply 700 and the ground line 800, and the normally open contact 271 of the seventh relay and the coil of the first time relay connected in series between the power supply 700 and the ground line 800, the normally open contact 231 of the third relay and the normally open contact of the seventh relay connected in series between the power supply 700 and the ground line 800 271 in parallel; when the second normally open contact 262 of the sixth relay is closed, the coil 230 of the third relay is energized, the normally open contact 231 of the third relay is closed, and the normally closed contact 232 of the third relay is disconnected; when the normally open contact 231 of the third relay is closed and / or the normally open contact 271 of the seventh relay is closed, the indicator light 600 lights up and the coil of the first time relay is energized, the normally closed contact 311 of the first time relay is disconnected with a delay, the first control circuit 10 is powered off, and all rollers stop operating; when the belt on the coal incoming side is blocked by coal, the normally open contact 271 of the seventh relay is closed.

[0060] The fourth control loop 40 can implement the following control process.

[0061] (1) During the operation of the roller screen, if any group of adjacent contactors loses power due to a fault, the third control circuit 30 triggers the fourth control circuit 40. The coil 260 of the sixth relay of the third control circuit 30 is continuously energized, and the second normally open contact 262 of the sixth relay is closed. The second normally open contact 262 of the sixth relay is connected in parallel with the roller power supply 700 switch fault judgment circuit and in series with the coil 230 of the third relay. Therefore, when the second normally open contact 262 of the sixth relay is closed, the coil 230 of the third relay is energized. The normally open contact 231 of the third relay is closed, and the indicator light 600 is lit to serve as a fault alarm prompt.

[0062] (2) The normally open contact 231 of the third relay is connected in parallel with the normally open contact 271 of the seventh relay and then connected in series with the coil of the first time relay. The seventh relay is energized in response to the coal blocking signal. The normally open contact 231 of the third relay is closed, which also energizes the coil of the first time relay. This triggers the normally closed contact of the first control loop 10 to open with a delay, thereby de-energizing the eighth sub-circuit and de-energizing the coils of all contactors, that is, the roller screen stops.

[0063] (3) The coil 230 of the third relay is energized, and the normally closed contact 232 of the third relay is disconnected, so that the second control loop 20 is de-energized. The coil 210 of the first relay in the second control loop 20 is de-energized, and the second normally open contact 212 of the first relay is disconnected again. The distributed control system 50 cannot receive the signal that the roller screen is working normally, and controls the belt on the coal-incoming side to stop operating.

[0064] Through the fourth control loop 40, the roller screen can be shut down and alarmed in response to a fault signal. The fault signal includes not only a signal that the switches of the power supply 700 of any group of adjacent rollers are all faulty, but also a signal that the contactors of any group of adjacent rollers are all faulty. Compared with the related art, which only responds to the failure of the switches of the power supply 700 of any group of adjacent rollers, the fourth control loop 40 responds to the fault more comprehensively, thereby improving the safety and reliability of the operation of the roller screen.

[0065] The present disclosure also provides a control system for a coal conveying roller screen, comprising: a coal conveying roller screen and a control loop of the coal conveying roller screen as described in any one of the first aspects, wherein the control loop is used to control the coal conveying roller screen.

[0066] The preferred embodiments of the present disclosure are described in detail above in conjunction with the accompanying drawings; however, the present disclosure is not limited to the specific details in the above embodiments. Within the technical concept of the present disclosure, a variety of simple modifications can be made to the technical solution of the present disclosure, and these simple modifications all fall within the protection scope of the present disclosure.

[0067] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present disclosure will not further describe various possible combinations.

[0068] In addition, any combination of the various embodiments of the present disclosure may be made, and as long as they do not violate the concept of the present disclosure, they should also be regarded as the contents disclosed by the present disclosure.

Claims

1. A control circuit for a coal conveying roller screen, characterized in that: include: A first control loop (10), a second control loop (20), a third control loop (30), and a fourth control loop (40); The first control loop (10) is used to control all rollers of the roller screen to start one by one, and if any roller fails to start during the starting process, all the started rollers are stopped; The second control loop (20) is used to monitor whether all rollers have been started and trigger the distributed control system (50) to start the coal-incoming side belt, and to monitor whether the roller screen has stopped operating and trigger the distributed control system (50) to stop the coal-incoming side belt; The third control loop (30) is used to monitor whether the contactors corresponding to any group of adjacent rollers are faulty; The fourth control loop (40) is used to stop the roller screen and alarm in response to a fault signal, wherein the fault signal includes a signal that the contactors of any group of adjacent rollers are faulty.

2. The control circuit according to claim 1, characterized in that: The second control loop (20) comprises a first subcircuit and a second subcircuit connected in series between a power source (700) and a ground line (800); The first subcircuit comprises a plurality of first normally open contacts (101) of contactors and a first normally open contact (211) of a first relay, the first normally open contacts (101) of all contactors being connected in series and then connected in parallel with the first normally open contact (211) of the first relay, and each contactor correspondingly controls the start and stop of a roller; The second sub-circuit comprises a coil (210) of a first relay; When the first normally open contacts (101) of all contactors are closed, the coil (210) of the first relay is energized, and the second normally open contacts (212) of the closed first relay trigger the distributed control system (50) to start the coal-incoming side belt.

3. The control circuit according to claim 2, characterized in that: The second sub-circuit comprises a first normally closed contact (221) of the second relay and a normally closed contact (232) of the third relay, the first normally closed contact (221) of the second relay, the normally closed contact (232) of the third relay, and the coil (210) of the first relay being connected in series; The second relay is used to control the roller screen to stop operating; The third relay is used to respond to the fault signal and act; When the first normally closed contact (221) of the second relay is disconnected and / or the normally closed contact (232) of the third relay is disconnected, the coil (210) of the first relay is de-energized and the second normally open contact (212) of the first relay is disconnected, triggering the distributed control system (50) to stop the coal-incoming side belt.

4. The control circuit according to claim 3, characterized in that: The first control loop (10) comprises a third sub-circuit and a fourth sub-circuit, the third sub-circuit being arranged between the power source (700) and the ground line (800); The third sub-circuit comprises a normally closed contact (311) of a first time relay, a roller screen start button (400), a second normally closed contact (222) of a second relay, a first normally closed contact (321) of the second time relay, and a coil (320) of the second time relay, which are connected in series, and the coil (320) of the second time relay is connected in parallel with the fourth sub-circuit; The fourth subcircuit comprises a fifth subcircuit and a sixth subcircuit connected in parallel, the fifth subcircuit comprises a seventh subcircuit, a delayed disconnection normally closed contact (334) of a third time relay, and a coil (330) of the third time relay connected in series, the seventh subcircuit comprises a first normally open contact (331) of the third time relay and a delayed closing normally open contact (342) of the fourth time relay connected in parallel, and the sixth subcircuit comprises a delayed disconnection normally closed contact (343) of the fourth time relay, a normally closed contact (333) of the third time relay, and a coil (340) of the fourth time relay connected in series; The second time relay is used to monitor whether the start of the roller screen has timed out. If all rollers fail to start successfully within the preset time, the second time relay will control the roller screen to stop and start; When the roller screen start button (400) is closed, the fourth sub-circuit is turned on, the coil (320) of the second time relay is energized, and the first normally closed contact (321) of the second time relay is disconnected after a delay, and the fourth sub-circuit is de-energized; The fourth sub-circuit is used to alternately energize the coil (340) of the fourth time relay and the coil (330) of the third time relay to generate a control signal for starting all the rolling rollers one by one.

5. The control circuit according to claim 4, characterized in that: The third sub-circuit further comprises a normally closed contact (214) of a first relay, wherein the normally closed contact (214) of the first relay is connected in series with the remaining elements of the third sub-circuit; When the coil (210) of the first relay is energized, the normally closed contact (214) of the first relay is disconnected, and the first control circuit (10) is de-energized.

6. The control circuit according to claim 5, characterized in that: The first control loop (10) comprises a third normally closed contact (223) of a second relay and an eighth subcircuit connected in series between a first node (900) and the ground wire (800), wherein the first node (900) is a node between a normally closed contact (311) of the first time relay and the roller screen start button (400); The eighth sub-circuit comprises a ninth sub-circuit and a plurality of roller start-up circuits (500) connected in parallel, and all the roller start-up circuits are connected in parallel; The ninth subcircuit comprises a tenth subcircuit and an eleventh subcircuit connected in parallel, the tenth subcircuit comprises a second normally open contact (332) of a third time relay and a coil (240) of a fourth relay connected in series, and the eleventh subcircuit comprises a normally open contact (341) of a fourth time relay and a coil (250) of a fifth relay connected in series; There are a plurality of fourth relays, each of which is used to control the start of an even-numbered roller; there are a plurality of fifth relays, each of which is used to control the start of an odd-numbered roller; Each roller start circuit (5i0) is used to control the start of a roller, and each roller start circuit (5i0) comprises a normally open contact (245) of a corresponding fourth relay or a fifth relay, a coil (1i0) of a contactor corresponding to the roller, a second normally open contact (1i3) of the contactor corresponding to the roller, and a third normally open contact (1j4) of a contactor corresponding to a subsequent roller; The eighth subcircuit is used to control all rollers to start in sequence according to the order of roller numbers. When the fourth subcircuit is energized, the coil (340) of the fourth time relay and the coil (330) of the third time relay are alternately energized, the coil (240) of the fourth relay and the coil (250) of the fifth relay are alternately energized, the normally open contact (245) of the fourth relay and the normally open contact (245) of the fifth relay are alternately closed, the contactors of all rollers are energized in sequence according to the order of the corresponding roller numbers, the rollers are started in sequence according to the order of the roller numbers, and the rollers are numbered in sequence from one end to the other according to their physical installation positions in the roller screen; The second relay is used to control the roller screen to stop operating. When the third normally closed contact (223) of the second relay is disconnected, the eighth sub-circuit is powered off, the contactors of all rollers are powered off, and all rollers are shut down.

7. The control circuit according to claim 6, characterized in that: The first control loop (10) further comprises a second normally closed contact (322) of a second time relay, a third normally closed contact (223) of the second relay, a second normally closed contact (322) of the second time relay, and the eighth sub-circuit connected in series; The second time relay is used to stop all started rollers if any roller fails to start during the starting process; When the second normally closed contact (322) of the second time relay is disconnected with a delay, the eighth sub-circuit is de-energized, the contactors of all rollers are de-energized, and all rollers are stopped.

8. The control circuit according to claim 7, characterized in that: The third control loop (30) comprises a twelfth sub-circuit, a thirteenth sub-circuit and a coil (260) of a sixth relay which are connected in series between the first node (900) and the ground line (800); The twelfth sub-circuit comprises a third normally open contact (213) of the first relay and a first normally open contact (261) of the sixth relay connected in parallel; The thirteenth sub-circuit includes a plurality of branches, each branch includes normally closed contacts of two contactors connected in series, and the two contactors are contactors corresponding to adjacent rollers; In the event that the contactors corresponding to any group of adjacent rollers fail, the normally closed contacts (102) of the contactors corresponding to any group of adjacent rollers are closed, the coil (260) of the sixth relay is energized, and the first normally open contact (261) of the sixth relay is closed, thereby linking the fourth control circuit (40).

9. The control circuit according to claim 8, characterized in that: The fourth control loop (40) comprises a fourteenth sub-circuit and a fifteenth sub-circuit which are linked together; The fourteenth sub-circuit comprises a second normally open contact (262) of a sixth relay and a coil (230) of a third relay connected in series between the power source (700) and the ground line (800); The fifteenth sub-circuit comprises a normally open contact (231) of a third relay and an indicator light (600) connected in series between the power source (700) and the ground wire (800), and a normally open contact (271) of a seventh relay and a coil of a first time relay connected in series between the power source (700) and the ground wire (800), the normally open contact (231) of the third relay and the normally open contact (271) of the seventh relay being connected in parallel; When the second normally open contact (262) of the sixth relay is closed, the coil (230) of the third relay is energized, the normally open contact (231) of the third relay is closed, and the normally closed contact (232) of the third relay is opened; When the normally open contact (231) of the third relay is closed and / or the normally open contact (271) of the seventh relay is closed, the indicator light (600) lights up and the coil of the first time relay is energized, the normally closed contact (311) of the first time relay is disconnected with a delay, the first control circuit (10) is de-energized, and all rollers stop operating; When the coal belt on the coal-incoming side is blocked by coal, the normally open contact (271) of the seventh relay is closed.

10. A control system for a coal conveying roller screen, characterized in that: include: A coal conveying roller screen and a control circuit for the coal conveying roller screen as claimed in any one of claims 1 to 9, wherein the control circuit is used to control the coal conveying roller screen.

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