An active protection device for a dehydrator screw conveyor

Abstract

The invention discloses an active protection device for a screw conveyor of a dehydrator. The power supply cables and the power supply on each cover plate are connected through a connector to form a protection circuit. An intermediate relay is connected in series on the protection circuit and its normally open contact is connected to the control circuit of the screw conveyor. The control circuit is designed to keep the screw conveyor stopped when the normally open contact is disconnected. The power supply cables are connected together through the connector, which has a certain hindering effect on the flipping of a single cover plate. When inspecting and cleaning, the power supply cable on the corresponding cover plate needs to be separated from the adjacent power supply cables through the connector, so that the protection circuit is disconnected and the screw conveyor is kept stopped. Not only can the cover plate be actively avoided from being opened when the machine is not shut down, but also the screw conveyor is kept stopped when the cover plate is not closed during maintenance and debugging, and no safety incident will occur due to the maintenance personnel accidentally starting the screw conveyor, which can effectively improve the stability and safety of sludge treatment.

Description

Technical Field

[0001] The invention belongs to the technical field of sludge treatment devices, and in particular relates to an active protection device for a screw conveyor of a dehydrator. Background Art

[0002] In order to facilitate the transportation and reuse of sludge, sewage treatment plants usually transport sludge mixed with a large amount of sewage to the sludge dewatering machine in the dewatering room, so that the sludge enters the sludge dewatering machine from the feed port. The motor of the sludge dewatering machine drives the filter cloth through the wave path formed by the staggered squeezing rollers through the driving roller, thereby squeezing and filtering out most of the water in the sludge to obtain relatively dry sludge residue. Finally, the sludge residue is discharged from the discharge port of the sludge dewatering machine to complete the dehydration of the sludge.

[0003] For example, a three-stage dehydration and drying system and method for sludge in a domestic sewage treatment plant disclosed in Chinese patent CN111847824A, and a secondary deep dehydration device for dehydrated sludge disclosed in Chinese patent CN205473318U, in order to facilitate the transportation of the sludge residue discharged from the sludge dehydrator to the outside of the dehydration room for transportation or secondary treatment of the sludge residue, a screw conveyor is generally provided below the discharge port of the sludge dehydrator, as shown in the attached document of this application. Figure 1 As shown, the screw conveyor includes a U-shaped casing 1 with an upward opening and extending laterally, a screw rod 2 is arranged in the casing along the length direction, and the screw rod is driven by a motor 3 arranged at the end of the casing to be used for screw conveying the mud residue in the casing. A mud funnel 4 is arranged at the opening of the casing near the motor, and the mud funnel is directly opposite to the discharge port to receive the mud residue and introduce it into the casing. In order to avoid the situation in which foreign objects, the corners of the clothes of the staff, or even the limbs of the staff are involved in the screw conveyor due to the staff's misoperation during the normal production of the screw conveyor, as shown in the attached document of this application, Figure 2 As shown, the applicant tried to continuously set a plurality of cover plates 5 along the length direction at the position of the casing mouth except the sludge funnel 4, and the cover plates 5 covered the casing mouth and were hinged to one side of the casing mouth, so that when necessary, the machine could be stopped and the cover plates could be flipped open to repair the screw conveyor; however, after trial use, it was found that during the maintenance and debugging process, it was easy for the maintenance personnel to accidentally start the screw conveyor when the cover plates were not closed, resulting in safety incidents; therefore, in order to improve the stability and safety of sludge treatment, the use of the screw conveyor needs to be further rectified and optimized. Summary of the invention

[0004] In view of the above-mentioned deficiencies in the prior art, an object of the present invention is to provide an active protection device for a screw conveyor for a dewatering machine, so as to solve the technical problem of poor safety in the use of the screw conveyor for the dewatering machine and achieve the effect of improving the stability and safety of sludge treatment.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions: An active protection device for a dehydrator screw conveyor comprises a screw conveyor, wherein the screw conveyor comprises a casing with a U-shaped cross section and an upward mouth, wherein a plurality of cover plates are continuously arranged on the casing along the length direction, wherein the cover plates cover the casing mouth and are hinged to one side of the casing mouth; a power supply cable is fixedly arranged on the cover plate, wherein two ends of the power supply cable are respectively located at two ends of the cover plate, and the opposite ends of two adjacent power supply cables are detachably electrically connected together through a connector, and the ends of the power supply cables located at two ends of the casing are respectively detachably electrically connected to two poles of a power supply through a connector, and the power supply and each power supply cable form a protection circuit, wherein a first intermediate relay is connected in series on the protection circuit, and a normally open contact of the first intermediate relay is electrically connected to a control circuit of the screw conveyor, and the screw conveyor is kept stopped when disconnected.

[0006] Furthermore, the connector adopts male and female connectors and includes a male connector and a female connector for plug-in connection.

[0007] Furthermore, a wire pressing plate is fixedly provided on the cover plate along the length direction, and two ends of the wire pressing plate are respectively close to the two ends of the cover plate. The cross-section of the wire pressing plate is U-shaped and the mouth abuts against the upper surface of the cover plate, so that a wiring channel is formed between the wire pressing plate and the cover plate. The power supply cable is movably arranged in the wiring channel and the two ends extend out to connect the male connector and the female connector respectively. The size of the male connector and the female connector is larger than the size of the wiring channel port.

[0008] Furthermore, the wire pressing plate is a metal plate, and both ends of the U-shape of the wire pressing plate extend outward laterally to form connecting parts, which abut against the upper surface of the cover plate and are connected by screws.

[0009] Furthermore, a plastic hose is provided on the outer jacket of the power supply cable, and the plastic hose is located in the wiring channel.

[0010] Furthermore, the first intermediate relay has two normally open contacts; the control circuit includes a main control circuit and a drive circuit for powering the motor of the screw conveyor, the main control circuit includes a first branch and a second branch, the first branch is connected in series with a normally closed push button switch, a normally open push button switch, a first normally open contact of the first intermediate relay and a second intermediate relay in sequence, the first normally open contact of the second intermediate relay is connected in parallel with the normally open push button switch, the second branch is connected in parallel with the first normally open contact of the first intermediate relay and the second intermediate relay, the second branch is connected in series with the second normally open contact of the first intermediate relay and a contactor in sequence, and the normally open main contact of the contactor is connected in series in the drive circuit.

[0011] Furthermore, the main control circuit also includes a third branch connected in parallel with the second branch, the third branch is connected in series with a first normally closed auxiliary contact of the contactor and a time relay, the delayed closing contact of the time relay is connected in series between the second normally open contact of the first intermediate relay and the contactor, and the normally open auxiliary contact of the contactor is connected in parallel with the delayed closing contact of the time relay.

[0012] Furthermore, the main control circuit also includes a fourth branch, one end of the fourth branch is connected before the normally closed push button switch, and the other end is connected between the delayed closing contact of the time relay and the contactor, and a maintenance knob switch is connected in series on the fourth branch.

[0013] Furthermore, the control circuit also includes a sub-control circuit, which includes a fifth branch and a sixth branch connected in parallel. The first intermediate relay is connected in series to the fifth branch, and the fifth branch serves as the protection circuit. The sixth branch is connected in series with a second normally closed auxiliary contact of the contactor, the second intermediate relay has a second normally open contact and an audible and visual alarm.

[0014] Furthermore, the power supply adopts a low-voltage direct current power supply, and the power supply cable is arranged on the cover plate along the length direction and is located at a side away from the hinge with the housing.

[0015] Compared with the prior art, the present invention has the following beneficial effects: 1. In the active protection device for the screw conveyor of the dehydrator described in the present invention, the power supply cables fixed on the cover plate are connected together through a connector, which has a certain hindering effect on the flipping and opening of a single cover plate. When the cover plate needs to be opened for inspection and cleaning, the power supply cable on the corresponding cover plate needs to be separated from the adjacent power supply cable through the connector, so that the protection circuit is disconnected, the first intermediate relay loses power, the normally open contact of the first intermediate relay is disconnected, and the control circuit keeps the screw conveyor stopped; not only can it actively avoid opening the cover plate when it is not shut down, but also during the maintenance and debugging process, the screw conveyor remains stopped when the cover plate is not closed, and there will be no safety incidents caused by the maintenance personnel accidentally starting the screw conveyor, which can effectively improve the stability and safety of sludge treatment.

[0016] 2. In the active protection device for the dehydrator screw conveyor described in the present invention, a male connector and a female connector are used as the connector. The male connector and the female connector are easy to be plugged in and connected and separated, which not only reduces the difficulty of operation and improves the use efficiency, but also the male connector and the female connector will automatically disengage after being subjected to a certain pulling force, which can effectively avoid direct opening of the cover plate without actively separating the male connector and the female connector, causing damage to the cable, the connection between the cable and the male connector, the connection between the cable and the female connector, the male connector or the female connector, which is beneficial to improving the practicality and stability of the active protection device.

[0017] 3. The active protection device for the dehydrator screw conveyor of the present invention, through the design of the control circuit, not only stops the screw conveyor motor and limits the starting by cutting off the protection circuit, but also realizes the delayed starting of the motor and the sound and light alarm reminder during the starting process through the time relay, contactor and two intermediate relays, so that the active protection device has good practicality and safety in use. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A top view of the screw conveyor for the sludge dewatering machine described in the background technology; Figure 2 for Figure 1 The screw conveyor shown is a top view with a cover plate installed on the housing opening; Figure 3 It is a schematic diagram of the active protection device for the screw conveyor of the dehydrator according to the embodiment; Figure 4 This is a schematic diagram of the connection between the wire pressing plate and the cover plate described in the embodiment; Figure 5 It is a wiring diagram of the active protection device for the dehydrator screw conveyor described in the embodiment; Among them, there are a casing 1, a screw rod 2, a motor 3, a sludge funnel 4, a cover plate 5, a power supply cable 6, a male connector 7, a female connector 8, a wire pressing plate 9, a connecting part 10, and a screw 11. DETAILED DESCRIPTION

[0019] To make the purpose, technical solution and advantages of the embodiments of the present invention more clear, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0020] Example: See also Figure 2 and Figure 3 An active protection device for a dehydrator screw conveyor includes a screw conveyor, which includes a casing 1 with a U-shaped cross-section and an upward mouth. A plurality of cover plates 5 are continuously provided on the casing 1 along the length direction, and the cover plates 5 cover the mouth of the casing 1 and are hinged to one side of the mouth of the casing 1; a power supply cable 6 is fixedly provided on the cover plate 5, and the two ends of the power supply cable 6 are respectively located at the two ends of the cover plate 5, and the opposite ends of the two adjacent power supply cables 6 are detachably electrically connected together through a connector, and the ends of the power supply cables 6 located at the two ends of the casing 1 are respectively detachably electrically connected to the two poles of the power supply through the connector, and the power supply and each power supply cable 6 constitute a protection circuit, and a first intermediate relay is connected in series on the protection circuit, and the normally open contact of the first intermediate relay is electrically connected to the control circuit of the screw conveyor, and keeps the motor 3 of the screw conveyor stopped when it is disconnected.

[0021] The active protection device for the screw conveyor of the dehydrator described in the present invention is provided with a plurality of cover plates 5 continuously along the length direction at the position of the mouth of the casing 1 except the sludge funnel 4, and the mouth of the casing 1 is covered by the cover plates 5, so as to avoid the situation in which foreign objects, corners of the clothes of the staff, or even limbs are drawn into the screw conveyor due to the staff's misoperation during the normal production of the screw conveyor; the cover plate 5 is hinged to one side of the mouth of the casing 1, so that when necessary, the machine can be stopped and the cover plate 5 can be flipped open to repair and clean the screw conveyor; on the basis of the cover plate 5 that can be flipped open being provided at the mouth of the casing 1, a power supply cable 6 is provided on each cover plate 5, and adjacent power supply cables 6 are connected by a connector, and the power supply cable 6 at the end is connected to the power supply through the connector, so as to form a protection circuit, a first intermediate relay is connected in series in the protection circuit, and the normally open contact of the first intermediate relay is electrically connected to the control circuit of the screw conveyor, and the control circuit is designed in the first intermediate relay. When the normally open contact of the relay is disconnected, the motor 3 of the screw conveyor remains stopped; in this way, the power supply cables 6 fixed on the cover plate 5 are connected together by the connector, which has a certain hindering effect on the flipping and opening of a single cover plate 5. When the cover plate 5 needs to be opened for inspection and cleaning, the power supply cable 6 on the corresponding cover plate 5 needs to be separated from the adjacent power supply cable 6 through the connector, so that the protection circuit is disconnected, the first intermediate relay loses power, the normally open contact of the first intermediate relay is disconnected, and the control circuit keeps the motor 3 of the screw conveyor stopped; not only can it actively avoid opening the cover plate 5 when it is not shut down, but also during the maintenance and debugging process, the motor 3 of the screw conveyor remains stopped when the cover plate 5 is not closed, and there will be no safety incidents caused by the maintenance personnel accidentally starting the screw conveyor; therefore, the active protection device described in the present invention can effectively solve the problem of poor safety in the use of screw conveyors for dehydrators, which is beneficial to improving the stability and safety of sludge treatment.

[0022] See also Figure 3 The connector adopts male and female connectors and includes a male connector 7 and a female connector 8 for plug-in connection; in this way, the opposite ends of the two adjacent power supply cables 6 are respectively connected to the male connector 7 and the female connector 8, and the connection and separation of the two adjacent power supply cables 6 are realized through the male connector 7 and the female connector 8. The male connector 7 and the female connector 8 are easy to be connected and separated by plugging, which can not only reduce the difficulty of operation and improve the use efficiency, but also the male connector 7 and the female connector 8 will automatically disengage after being subjected to a certain pulling force, which can effectively avoid directly opening the cover plate 5 without actively separating the male connector 7 and the female connector 8, causing damage to the cable, the connection between the cable and the male connector 7, the connection between the cable and the female connector 8, the male connector 7 or the female connector 8, which is beneficial to improve the practicality and stability of the active protection device.

[0023] See also Figure 3 and Figure 4A wire pressing plate 9 is fixedly provided on the cover plate 5 along the length direction, and the two ends of the wire pressing plate 9 are respectively close to the two ends of the cover plate 5. The cross-section of the wire pressing plate 9 is U-shaped and the mouth abuts against the upper surface of the cover plate 5, so that a wiring channel is formed between the wire pressing plate 9 and the cover plate 5. The power supply cable 6 is movably arranged in the wiring channel and the two ends extend out to connect the male connector 7 and the female connector 8 respectively. The size of the male connector 7 and the female connector 8 is larger than the size of the wiring channel port.

[0024] In this way, the power supply cable 6 is restricted by the wire pressing plate 9 and cannot be vertically separated from the cover plate 5, so as to realize the above-mentioned power supply cable 6 fixed on the cover plate 5, and then realize that each power supply cable 6 is connected together through the connector, which has a certain hindering effect on the flipping and opening of a single cover plate 5. At the same time, the power supply cable 6 can move laterally in the wiring channel so as to move and adjust the male connector 7 and the female connector 8 to complete the plugging and separation; the size of the male connector 7 and the female connector 8 is larger than the size of the wiring channel port, which can prevent the male connector 7 and the female connector 8 from entering the wiring channel and the power supply cable 6 from being separated from the corresponding cover plate 5, which is beneficial to improving the reliability of the active protection device; during implementation, the length of the wire pressing plate 9 should be close to the length of the cover plate 5, and the length of the two ends of the power supply cable 6 should be as short as possible while meeting the requirements for connecting the male connector 7 and the female connector 8, so as to ensure the effect of preventing a single cover plate 5 from opening.

[0025] See also Figure 3 and Figure 4 The wire pressing plate 9 is a metal plate, and the U-shaped ends of the wire pressing plate 9 extend outward laterally to form connecting parts 10, which abut against the upper surface of the cover plate 5 and are connected by screws 11; in this way, the wire pressing plate 9 is not only easy to install and disassemble, but also has good structural strength, and can provide reliable restriction and protection for the power supply cable 6; in this embodiment, a plastic hose is provided on the outer sleeve of the power supply cable 6, and the plastic hose is located in the wiring channel; in this way, the power supply cable 6 is separated from the metal wire pressing plate 9 by the plastic hose, which can not only avoid the power supply cable 6 and the wire pressing plate 9 from scratching and breaking during use, but also avoid leakage.

[0026] See also Figure 3 In order to ensure that the single cover plate 5 is not hindered from being flipped open and to facilitate the staff to notice when opening the cover plate 5, the present invention designs that the power supply cable 6 is arranged on the cover plate 5 along the length direction and is located away from the side hinged with the housing 1; see Figure 5 In order to improve the safety of the active protection device, the power supply adopts a low-voltage DC power supply. In this embodiment, a switching power supply of AC220V to DC12V is adopted.

[0027] See also Figure 5The first intermediate relay KA1 has two normally open contacts; the control circuit includes a main control circuit and a drive circuit for powering the motor M of the screw conveyor, the main control circuit includes a first branch and a second branch, the first branch is connected in series with a normally closed button switch SB1, a normally open button switch SB2, a first normally open contact KA1-1 of the first intermediate relay KA1 and a second intermediate relay KA2 in sequence, the first normally open contact KA2-1 of the second intermediate relay KA2 is connected in parallel with the normally open button switch SB2, the second branch is connected in parallel with the first normally open contact KA1-1 of the first intermediate relay KA1 and the second intermediate relay KA2, the second branch is connected in series with the second normally open contact KA1-2 of the first intermediate relay KA1 and a contactor KM in sequence, and the normally open main contact of the contactor KM is connected in series in the drive circuit.

[0028] In this way, when the cover is closed and the protection circuit is turned on, the first intermediate relay KA1 remains energized, and the first normally open contact KA1-1 and the second normally open contact KA1-2 of the first intermediate relay KA1 remain closed. At this time, the normally open button switch SB2 can be pressed to energize the second intermediate relay KA2, and the first normally open contact KA2-1 of the second intermediate relay KA2 is closed to complete self-locking, so that the second branch is turned on, the contactor KM is energized, and the normally open main contact of the contactor KM is closed, so that the motor M of the screw conveyor is started; after the motor M is started, the normally closed button switch SB1 can be pressed to disconnect the first branch temporarily, the second intermediate relay KA2 loses power, and the first normally open contact KA2-1 of the second intermediate relay KA2 is disconnected again to release the self-locking, the second branch is disconnected, the contactor KM loses power, and the normally open main contact of the contactor KM is disconnected, so that the motor M of the screw conveyor stops; When the protection circuit is disconnected due to the opening of the cover, the first intermediate relay KA1 loses power, and the first normally open contact KA1-1 and the second normally open contact KA1-2 of the first intermediate relay KA1 are both disconnected, so that the first branch and the second branch are both disconnected, which not only stops the motor M, but also cannot be started again by pressing the normally open button switch SB2, thereby achieving the above-mentioned effect of "not only actively avoiding opening the cover when it is not shut down, but also during maintenance and debugging, the screw conveyor remains stopped when the cover is not closed, and there will be no safety incidents caused by maintenance personnel accidentally starting the screw conveyor."

[0029] See also Figure 5 The main control circuit also includes a third branch connected in parallel with the second branch, and the first normally closed auxiliary contact KM-1 of the contactor KM and the time relay KT are connected in series on the third branch. The delayed closing contact of the time relay KT is connected in series between the second normally open contact KA1-2 of the first intermediate relay KA1 and the contactor KM, and the normally open auxiliary contact of the contactor KM is connected in parallel with the delayed closing contact of the time relay KT.

[0030] In this way, the delayed closing contact of the time relay KT is set in series on the third branch. The delayed closing contact of the time relay KT closes after the time relay KT is energized for a period of time, so that when the normally open button switch SB2 is pressed to start the motor M, the contactor KM will not be energized quickly, thereby delaying the start of the motor M. This leaves time for the staff to stay away from the screw conveyor after maintenance and cleaning, which is beneficial to improving the safety of sludge treatment.

[0031] See also Figure 5 The main control circuit also includes a fourth branch, one end of the fourth branch is connected before the normally closed button switch SB1, and the other end is connected between the delayed closing contact of the time relay KT and the contactor KM. A maintenance knob switch SA is connected in series on the fourth branch.

[0032] In this way, after the cover is opened, the protection circuit is disconnected, the first intermediate relay KA1 loses power, and the normally closed push button switch SB1 and the normally open push button switch SB2 fail to control the start and stop of the motor M, the fourth branch can be connected or disconnected through the maintenance knob switch SA, and the contactor KM can be directly controlled to gain or lose power to control the start and stop of the motor M to meet the operational needs of maintenance and commissioning personnel in specific situations. During implementation, the maintenance knob switch SA should be set in a locked maintenance control box to avoid abuse.

[0033] See also Figure 5 The control circuit also includes a sub-control circuit, which includes a fifth branch and a sixth branch connected in parallel. The first intermediate relay KA1 is connected in series to the fifth branch. The fifth branch serves as the protection circuit. The sixth branch is connected in series with the second normally closed auxiliary contact KM-2 of the contactor KM, the second normally open contact KA2-2 of the second intermediate relay KA2 and the sound and light alarm BSG.

[0034] In this way, when the cover is closed, the first intermediate relay KA1 is energized, and after the normally open push button switch SB2 is pressed and the second intermediate relay KA2 is energized, the second normally open contact KA2-2 of the second intermediate relay KA2 is closed, so that the sixth branch is turned on, and the sound and light alarm BSG is energized and works; when the delayed action of the time relay KT ends and the contactor KM is energized, the second normally closed auxiliary contact KM-2 of the contactor KM is disconnected, so that the sixth branch is disconnected, and the sound and light alarm BSG loses power and stops; during the period from pressing the normally open push button switch SB2 to starting the motor M, the sound and light alarm BSG emits an alarm tone and lighting effects to alert the staff near the screw conveyor to avoid safety incidents caused by the sudden start of the screw conveyor; during implementation, the sound and light alarm BSG should be set close to the screw conveyor.

[0035] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the technical solution. Those skilled in the art should understand that those modifications or equivalent substitutions of the technical solution of the present invention that do not depart from the purpose and scope of the technical solution should be included in the scope of the claims of the present invention.

Claims

1. An active protection device for a dehydrator screw conveyor, characterized in that: The invention comprises a screw conveyor, which comprises a casing with a U-shaped cross section and an upward opening, a plurality of cover plates are continuously arranged on the casing along the length direction, the cover plates cover the casing opening and are hinged to one side of the casing opening; a power supply cable is fixedly arranged on the cover plate, two ends of the power supply cable are respectively located at two ends of the cover plate, the opposite ends of two adjacent power supply cables are detachably electrically connected together through a connector, the ends of the power supply cables located at two ends of the casing are respectively detachably electrically connected to the two poles of the power supply through the connector, the power supply and each power supply cable form a protection circuit, a first intermediate relay is connected in series on the protection circuit, the normally open contact of the first intermediate relay is electrically connected to the control circuit of the screw conveyor, and the screw conveyor is kept stopped when disconnected.

2. According to claim 1, an active protection device for a dehydrator screw conveyor is characterized in that: The connector adopts male and female connectors and includes a male connector and a female connector for plug-in connection.

3. According to claim 2, an active protection device for a dehydrator screw conveyor is characterized in that: A wire pressing plate is fixedly provided on the upper length direction of the cover plate, with two ends of the wire pressing plate close to the two ends of the cover plate respectively. The cross-section of the wire pressing plate is U-shaped and the mouth abuts against the upper surface of the cover plate, so that a wiring channel is formed between the wire pressing plate and the cover plate. The power supply cable is movably arranged in the wiring channel and the two ends extend out to connect the male connector and the female connector respectively. The size of the male connector and the female connector is larger than the size of the wiring channel port.

4. The active protection device for a dehydrator screw conveyor according to claim 3, characterized in that: The wire pressing plate is a metal plate, and both ends of the U-shape of the wire pressing plate extend outwards laterally to form connecting parts, which abut against the upper surface of the cover plate and are connected by screws.

5. The active protection device for a dehydrator screw conveyor according to claim 4, characterized in that: A plastic hose is provided on the outer jacket of the power supply cable, and the plastic hose is located in the wiring channel.

6. The active protection device for a dehydrator screw conveyor according to claim 1, characterized in that: The first intermediate relay has two normally open contacts; the control circuit includes a main control circuit and a drive circuit for powering the motor of the screw conveyor, the main control circuit includes a first branch and a second branch, the first branch is connected in series with a normally closed push button switch, a normally open push button switch, a first normally open contact of the first intermediate relay and a second intermediate relay in sequence, the first normally open contact of the second intermediate relay is connected in parallel with the normally open push button switch, the second branch is connected in parallel with the first normally open contact of the first intermediate relay and the second intermediate relay, the second branch is connected in series with the second normally open contact of the first intermediate relay and a contactor in sequence, and the normally open main contact of the contactor is connected in series in the drive circuit.

7. The active protection device for a dehydrator screw conveyor according to claim 6, characterized in that: The main control circuit also includes a third branch connected in parallel with the second branch, the first normally closed auxiliary contact of the contactor and a time relay are connected in series on the third branch, the delayed closing contact of the time relay is connected in series between the second normally open contact of the first intermediate relay and the contactor, and the normally open auxiliary contact of the contactor is connected in parallel with the delayed closing contact of the time relay.

8. The active protection device for a dehydrator screw conveyor according to claim 7, characterized in that: The main control circuit also includes a fourth branch, one end of which is connected before the normally closed button switch and the other end is connected between the delayed closing contact of the time relay and the contactor. A maintenance knob switch is connected in series on the fourth branch.

9. The active protection device for a dehydrator screw conveyor according to claim 7, characterized in that: The control circuit also includes a sub-control circuit, which includes a fifth branch and a sixth branch connected in parallel. The first intermediate relay is connected in series to the fifth branch, and the fifth branch serves as the protection circuit. The sixth branch is connected in series with a second normally closed auxiliary contact of the contactor, a second normally open contact of the second intermediate relay, and an audible and visual alarm.

10. The active protection device for a dehydrator screw conveyor according to claim 1, characterized in that: The power supply adopts a low-voltage direct current power supply, and the power supply cable is arranged on the cover plate along the length direction and is located at a side away from the hinge with the housing.

Images