Pre-filter for controlling backwash and blowdown of a top control and control method

Abstract

The application relates to a front filter for top control backwashing and blowdown, and a control method, which comprises a controller, a valve head body provided with an inlet port, an outlet port and a filter bottle assembly port, and further comprises a driving motor assembly, a control assembly, a transmission assembly, a blowdown switching assembly and a backwashing assembly; the driving motor assembly comprises a driving motor fixed to the valve head body, and the valve head body is provided with an assembly cavity matched with the output end of the driving motor; the control assembly comprises a first limit switch; the transmission assembly comprises a transmission shaft coupled with the output end of the driving motor and rotationally matched with the assembly cavity; the blowdown switching assembly is arranged at the end of the transmission shaft, and the transmission shaft can move axially under the action of the driving motor. The valve head structure is more optimized, convenient to install, use and maintain, backwashing, blowdown and / or leakage protection valve closing actions can be controlled through one motor, the structure is compact, and the automation degree and reliability are high.

Description

Technical Field

[0001] This invention relates to a pre-filter and control method for top-controlled backwashing and sewage discharge, belonging to the technical field of water purification equipment. Background Technology

[0002] Existing pre-filters include: a valve head, a filter bottle connected to the upper end of the valve head, and a drainage assembly connected to the lower end of the filter bottle. A filter screen frame is installed inside the filter bottle, and a filter screen is fitted onto the outer wall of the filter screen frame. During use, water flows from the inlet of the valve head into the gap between the filter bottle and the filter screen. After being filtered by the filter screen, water flows into the center of the filter screen frame, and then from the center of the filter screen frame to the outlet of the valve head.

[0003] During the use of a pre-filter, it is necessary to periodically clean the impurities adhering to the filter screen surface in situ, and then discharge them through the drainage component. The efficient operation of the cleaning / scraping structure is crucial. In the existing technology, there are cleaning / scraping structures driven by motors, cleaning / scraping structures driven by impellers, etc., and backwashing is also an efficient means of cleaning the filter screen of the pre-filter. However, the existing cleaning / scraping structures do not yet have a drive motor set on the top of the valve head to control the switching between normal filtration and backwashing modes. In addition, achieving fully automatic cleaning and sewage discharge of the pre-filter is also a future development trend of this type of product. Furthermore, water leakage is inevitable during the use of pre-filters. When water leakage is detected, it is crucial to close the inlet and outlet channels of the pre-filter in time. Those skilled in the art have been exploring the use of a drive motor set on the top of the valve head to achieve valve closure when water leakage occurs (i.e., simultaneously closing the inlet and outlet channels). This invention solves the aforementioned technical problems and provides a pre-filter and control method with a more optimized structure and easy industrial implementation, featuring top control of backwashing and sewage discharge. Summary of the Invention

[0004] The second objective of this invention is to address the shortcomings of existing pre-filters by providing a top-controlled pre-filter for backwashing and sewage discharge, employing the aforementioned valve head structure. This pre-filter features automatic switching between backwashing, sewage discharge, and filtration restoration modes, and / or integrates a leak-proof valve shut-off protection function, enabling the water circuit to be shut off in the event of a leak.

[0005] One objective of this invention is to address the shortcomings of existing pre-filters by providing a top-controlled method for backwashing and sewage discharge of the pre-filter. This method uses a single motor to control the backwashing, sewage discharge, and / or leakage protection valve operation, resulting in a compact structure, high degree of automation, and high reliability.

[0006] The technical solution adopted by this invention to solve its technical problem is:

[0007] The top-controlled backwashing and sewage discharge valve head structure includes a controller, a valve head body with an inlet port, an outlet port and a filter bottle assembly port, a filter bottle, a filter assembly inside the filter bottle and a sewage discharge chamber at the bottom of the filter bottle, and also includes a drive motor assembly, a control assembly, a transmission assembly, a sewage discharge switching assembly and a backwashing assembly.

[0008] The drive motor assembly includes a drive motor, which is fixed to the valve head body. The valve head body is provided with an assembly cavity adapted to the output end of the drive motor.

[0009] The control component includes a first limit switch;

[0010] The transmission assembly includes a transmission shaft, which is connected to the output end of the drive motor and rotates with the assembly cavity. The sewage discharge switching component is located at the end of the transmission shaft, and the transmission shaft can move axially under the action of the drive motor.

[0011] The sewage switching assembly includes a sewage plug body, which includes a connecting part and a functional part. The connecting part and / or the functional part are provided with a sewage discharge notch. The connecting part is connected to the transmission part. The functional part is provided with at least a first sealing element. The sewage plug body can open or close the sewage discharge channel through the sewage discharge notch under the drive of the drive motor assembly.

[0012] The backwash assembly includes a backwash frame, a backwash filter, and a sealing part. The backwash assembly is sleeved on the drive shaft and can move axially with the drive shaft under the drive of the drive motor assembly.

[0013] The filter assembly includes a filter frame, filter elements, and a filter frame inlet channel. The backwash frame is inserted into the filter frame and is axially slidingly sealed.

[0014] When the drive shaft moves axially from the initial position to the first limit switch position, the sealing part can close the water inlet channel of the filter frame and open the backwash water channel of the backwash filter screen, while the drain plug opens the drain channel of the drain chamber; when it moves axially to the initial position, the water inlet channel of the filter frame opens and the backwash water channel of the backwash filter screen closes, while the drain plug closes the drain channel of the drain chamber.

[0015] The initial position is the position where the pre-filter is in the filtering state, and the drive motor and the first limit switch are both electrically connected to the controller.

[0016] Preferably, the control component further includes a second limit switch located below the first limit switch. The sealing part has a first sealing part and a second sealing part, and the backwash filter screen is located between the first sealing part and the second sealing part. When the first limit switch is in position, the first sealing part closes the water inlet channel of the pre-filter filtration mechanism. When the drive motor drives the transmission shaft to continue running to the second limit switch position, the second sealing part closes the inner inlet of the water inlet port and the inner outlet of the water outlet port, thereby closing the valve. The second limit switch is electrically connected to the controller.

[0017] Preferably, the inlet port of the valve head body is further provided with a flow sensor electrically connected to the controller. The flow sensor transmits flow data to the controller. When the flow data exceeds the set value, the controller sends a valve-closing command to the drive motor. After the fault is cleared, the controller receives an external command and sends a valve-opening command to the drive motor.

[0018] Alternatively, the valve can be manually closed or unclosed by sending a command to the controller, which will then send a running command to the drive motor in response.

[0019] The flow sensors include Hall effect flow sensors, electromagnetic flow sensors, vortex flow sensors, impeller flow sensors, and ultrasonic flow sensors.

[0020] Preferably, the filter frame is a filter mesh frame, and the filter element is a filter mesh, PP cotton, or filter membrane; or the filter frame is a stacked frame, and the filter element is a stacked filter; the controller can be connected to a remote server or user terminal via wireless communication, and the controller is provided with a remote communication unit, which includes a wireless communication module electrically connected to the controller's circuit board.

[0021] Preferably, the filter frame is a stacked frame, the filter element is a filter stack, and a stacked adjustment component is provided at the lower end of the stacked frame. The stacked adjustment component abuts against the filter stack, and the stacked adjustment component can move axially with the transmission shaft to release the abutment and loosen the filter stack or restore the abutment and tighten the filter stack. The controller has a processor function, and the wireless communication module is any one or a combination of two of the following: 2G module, 3G module, 4G module, 5G module, and WiFi module. The remote server and user terminal can receive information or remotely control the controller through the wireless communication module. At least one MCU is integrated on the circuit board of the controller, and the operation of its electrically connected components is controlled by the MCU. The wireless communication module is also integrated on the circuit board of the controller.

[0022] Preferably, the filter disc adjustment component includes an adjustment seat and an elastic reset element. One end of the elastic reset element is fixed to the adjustment seat, and the other end can abut or be fixed to the inner wall of the bottom of the filter bottle. The adjustment seat and the drive shaft can be axially fixed. When the drive shaft moves axially downward, the elastic reset element is compressed, releasing the abutment and loosening the filter discs. When the drive shaft moves axially upward, the elastic reset element can reset, restoring the abutment and pressing the filter discs.

[0023] Preferably, the diameter of the connecting part is smaller than the diameter of the functional part, and the gap between the outer periphery of the connecting part and the sewage discharge chamber constitutes a sewage discharge notch. The control component also includes an initial position limit switch, which is set at the initial position and electrically connected to the controller to achieve precise reset. The first limit switch, the second limit switch and the initial limit switch are selected from any one or more of photoelectric induction switches, Hall switches and micro switches.

[0024] Preferably, the transmission shaft includes a rotating shaft and a transmission rod. The rotating shaft has an external thread, and the assembly cavity has an internal thread. The rotating shaft and the transmission rod are detachably connected, and the output shaft of the drive motor is detachably connected to the rotating shaft.

[0025] Preferably, the rotating shaft is sleeved with the transmission rod and is provided with a snap ring assembly port for fixing by snap ring. The end of the rotating shaft is provided with a special-shaped hole or special-shaped part, and the end of the drive motor output shaft is provided with a matching special-shaped part or special-shaped hole, and is connected by the cooperation of the special-shaped hole and the special-shaped part.

[0026] Preferably, the drive motor assembly further includes a drive motor mounting base, the top of which is provided with a drive motor assembly slot, the drive motor being snapped into the drive motor assembly slot, and the side of the drive motor mounting base is provided with a limit switch mounting slot, the first limit switch, the second limit switch and the initial limit switch being fixed in the limit switch mounting slot.

[0027] Preferably, the drive shaft and transmission rod are each provided with a limiting part, and the two ends of the backwash frame abut against the limiting parts of the drive shaft and transmission rod respectively.

[0028] Preferably, the first sealing element is an O-ring, the functional part of the drain plug body is provided with a sealing element assembly groove, the first sealing element is fixed in the sealing element assembly groove, and the connecting part is also provided with a drain guide groove.

[0029] A control method for a pre-filter, the control method comprising the following steps:

[0030] Step S1: Assemble the pre-filter and adjust it to the initial position. Set the controller to the initial position as the filtration mode, the first limit switch position as the backwash mode, and the second limit switch position as the valve closing mode.

[0031] Step S2: The controller presets the parameters for starting and stopping the backwashing of the pre-filter. The parameters include any one or more of time, pressure, and flow rate, and configures an appropriate sensor to be electrically connected to the controller.

[0032] Step S3: The controller presets parameters for closing the valve when the pre-filter is leaking and opening the valve when it is not leaking. The parameters include any one or more of flow rate, flow velocity, and the duration of constant flow velocity, and configures an appropriate sensor to be electrically connected to the controller.

[0033] Step S4: The pre-filter operates in filtration mode. When the backwashing parameters reach the preset opening parameters, the drive motor rotates and the drive shaft moves axially downward to the first limit switch position. The sealing part closes the filter frame water inlet channel (11), and the backwashing water channel of the backwashing filter screen opens. The controller operates in backwashing mode. When the backwashing parameters reach the preset stop parameters, the drive motor reverses and the drive shaft moves axially upward to the initial position. The sealing part opens the filter frame water inlet channel (11), and the backwashing water channel of the backwashing filter screen closes.

[0034] Step S5: When the operating parameters of the pre-filter reach the preset valve closing parameters under leakage conditions, the drive motor rotates and the drive shaft moves axially downward to the second limit switch position, closing the water inlet port near the water inlet channel (11) of the filter frame and the inner outlet of the water outlet port.

[0035] Step S6: When the operating parameters of the pre-filter reach the preset valve opening parameters under non-leakage conditions, the drive motor reverses and drives the transmission shaft to move axially upward to the first limit switch position to enter the backwashing mode, or directly moves axially upward to the initial position to enter the filtration mode.

[0036] The controller repeats control steps S4-S6 according to the operating status.

[0037] The beneficial effects of this invention are:

[0038] The valve head has an optimized structure, is easy to install, use and maintain. It controls the backwashing, sewage discharge and / or leakage protection valve closing action through a single motor. It has a compact structure and a high degree of automation and reliability.

[0039] This pre-filter features automatic switching between backwashing, sewage discharge, and filtration restoration modes, and / or integrates a leak-proof valve shut-off protection function, which means it can shut off the water supply in the event of a leak. Attached Figure Description

[0040] Figure 1 This is a schematic diagram of the structure of the present invention;

[0041] Figure 2 This is a schematic diagram of the structure of the present invention;

[0042] Figure 3 This is a schematic diagram of the structure of the present invention;

[0043] Figure 4 This is a schematic diagram of the structure of the present invention (filtered state);

[0044] Figure 5 This is a schematic diagram of the structure of the present invention (backwashing and sewage discharge state);

[0045] Figure 6 This is a schematic diagram of the structure of the present invention (valve closed, out state).

[0046] In the diagram: 1. Valve head body, 2. Drive motor, 3. Drain plug body, 31. Connecting part, 32. Functional part, 33. First sealing element, 4. Backwash frame, 5. Sealing part, 51. First sealing part, 52. Second sealing part, 6. Backwash filter screen, 7. Rotating shaft, 8. Transmission rod, 9. Limit switch mounting slot, 10. Filter frame, 11. Filter frame inlet channel, 12. Filter element, 13. Disc adjustment piece, 14. Filter bottle. Detailed Implementation

[0047] The technical solution of the present invention will be further described in detail below through specific embodiments and in conjunction with the accompanying drawings.

[0048] like Figure 1-6 As shown, the valve head structure for controlling backwashing and sewage discharge at the top includes a controller (not shown in the figure), a valve head body 1 with an inlet port, an outlet port and a filter bottle assembly port, a filter bottle 14, a filter assembly inside the filter bottle 14 and a sewage discharge chamber at the bottom of the filter bottle 14, and also includes a drive motor assembly, a control assembly, a transmission assembly, a sewage discharge switching assembly and a backwashing assembly.

[0049] The drive motor assembly includes a drive motor 2, which is fixed to the valve head body 1. The valve head body 1 is provided with an assembly cavity that is adapted to the output end of the drive motor 2.

[0050] The control component includes a first limit switch;

[0051] The transmission assembly includes a transmission shaft, which is connected to the output end of the drive motor 1 and rotates with the assembly cavity. The sewage discharge switching assembly is located at the end of the transmission shaft, and the transmission shaft can move axially under the action of the drive motor 1.

[0052] The sewage switching assembly includes a sewage plug body 3, which includes a connecting part 31 and a functional part 32. The connecting part 31 and / or the functional part 32 are provided with a sewage discharge notch. Specifically, the diameter of the connecting part 31 is smaller than the diameter of the functional part 32. The gap between the outer periphery of the connecting part 31 and the sewage discharge chamber constitutes the sewage discharge notch. The connecting part 31 is connected to the transmission part. The functional part is provided with at least a first sealing element 33. The sewage plug body 3 can open or close the sewage discharge channel under the drive of the drive motor assembly.

[0053] The backwash assembly includes a backwash frame 4, a backwash filter 6, and a sealing part 5. The backwash assembly is sleeved on the drive shaft and can move axially with the drive shaft under the drive of the drive motor assembly.

[0054] The filter assembly includes a filter frame, filter elements, and a filter frame inlet channel. The backwash frame is inserted into the filter frame and is axially slidingly sealed.

[0055] When the drive shaft moves axially from the initial position to the first limit switch position, the sealing part can close the water inlet channel of the filter frame and open the backwash water channel of the backwash filter screen, while the drain plug opens the drain channel of the drain chamber; when it moves axially to the initial position, the water inlet channel of the filter frame opens and the backwash water channel of the backwash filter screen closes, while the drain plug closes the drain channel of the drain chamber.

[0056] The initial position is the position where the pre-filter is in the filtering state, and the drive motor 2 and the first limit switch are both electrically connected to the controller.

[0057] In this embodiment, the control component further includes a second limit switch located below the first limit switch. The sealing part 5 is provided with a first sealing part 51 and a second sealing part 52. The backwash filter 6 is disposed between the first sealing part 51 and the second sealing part 52. When the first limit switch is in position, the first sealing part 51 closes the water inlet channel 11 of the filter frame. When the drive motor 2 drives the transmission shaft to continue running to the second limit switch position, the second sealing part 52 closes the water inlet port near the water inlet channel 11 of the filter frame and the inner outlet of the outlet port, thereby closing the valve. The second limit switch is electrically connected to the controller.

[0058] In this embodiment, a flow sensor electrically connected to the controller is also provided in the channel of the water inlet port of the valve head body 1. The flow sensor transmits flow data to the controller. When the flow data exceeds the set value, the controller sends a valve closing command to the drive motor. After the fault is cleared, the controller sends a valve opening command to the drive motor after receiving the external command. Alternatively, the controller can send a valve closing or valve cancellation command to the controller manually. After the controller responds, it sends a running command to the drive motor.

[0059] The flow sensors include Hall effect flow sensors, electromagnetic flow sensors, vortex flow sensors, impeller flow sensors, and ultrasonic flow sensors.

[0060] In this embodiment, the filter frame 10 is a filter mesh frame, and the filter element 12 is a filter mesh, PP cotton, or filter membrane; or the filter frame 10 is a stacked frame, and the filter element 12 is a filter stack; the controller can be connected to a remote server or user terminal via wireless communication, and the controller is provided with a remote communication unit, which includes a wireless communication module electrically connected to the controller's circuit board.

[0061] Specifically, the filter frame 10 is a stacked frame, the filter element 12 is a filter stack, and a stacked adjustment member 13 is provided at the lower end of the stacked frame. The stacked adjustment member 13 abuts against the filter stack and can move axially with the transmission shaft to release the abutment and loosen the filter stack or restore the abutment and tighten the filter stack. The controller has a processor function, and the wireless communication module is any one or a combination of two of the following: 2G module, 3G module, 4G module, 5G module, and WiFi module. The remote server and user terminal can receive information or remotely control the controller through the wireless communication module. At least one MCU is integrated on the circuit board of the controller, and the operation of its electrically connected components is controlled by the MCU. The wireless communication module is also integrated on the circuit board of the controller.

[0062] More specifically, the filter disc adjustment component 13 includes an adjustment seat and an elastic reset element. One end of the elastic reset element is fixed to the adjustment seat, and the other end can abut or be fixed to the inner wall of the bottom of the filter bottle 14. The adjustment seat and the transmission shaft can be axially fixed. When the transmission shaft moves axially downward, the elastic reset element is compressed, releasing the abutment and loosening the filter discs. When the transmission shaft moves axially upward, the elastic reset element can be reset, restoring the abutment and pressing the filter discs.

[0063] In this embodiment, the control component further includes an initial position limit switch, which is set at the initial position and electrically connected to the controller to achieve precise reset. The first limit switch, the second limit switch, and the initial limit switch are selected from any one or more of photoelectric induction switches, Hall switches, and micro switches.

[0064] In this embodiment, the transmission shaft includes a rotating shaft 7 and a transmission rod 8. The rotating shaft 7 is provided with an external thread, and the assembly cavity is provided with an internal thread. The rotating shaft 7 and the transmission rod 8 are detachably connected. The output shaft of the drive motor 2 is detachably connected to the rotating shaft 7.

[0065] In this embodiment, the rotating shaft 7 is sleeved with the transmission rod 8 and is provided with a snap ring assembly port for fixing by snap ring. The end of the rotating shaft 7 is provided with a special-shaped hole or special-shaped part, and the end of the drive motor output shaft is provided with a matching special-shaped part or special-shaped hole, which is connected by the cooperation of the special-shaped hole and the special-shaped part.

[0066] In this embodiment, the drive motor assembly further includes a drive motor mounting base. The top of the drive motor mounting base is provided with a drive motor assembly slot, in which the drive motor is snapped. The side of the drive motor mounting base is provided with a limit switch mounting slot. The first limit switch, the second limit switch, and the initial limit switch are fixed in the limit switch mounting slot 9.

[0067] In this embodiment, the drive shaft 7 and the transmission rod 8 are respectively provided with limiting parts, and the two ends of the backwash frame 4 abut against the limiting parts of the drive shaft 7 and the transmission rod 8 respectively.

[0068] In this embodiment, the first sealing element 33 adopts an O-ring seal, the functional part 32 of the drain plug body 3 is provided with a sealing element assembly groove, the first sealing element 33 is fixed in the sealing element assembly groove, and the connecting part 31 is also provided with a drain guide groove.

[0069] A control method for a pre-filter, the control method comprising the following steps:

[0070] Step S1: Assemble the pre-filter and adjust it to the initial position. Set the controller to the initial position as the filtration mode, the first limit switch position as the backwash mode, and the second limit switch position as the valve closing mode.

[0071] Step S2: The controller presets the parameters for starting and stopping the backwashing of the pre-filter. The parameters include any one or more of time, pressure, and flow rate, and configures an appropriate sensor to be electrically connected to the controller.

[0072] Step S3: The controller presets parameters for closing the valve when the pre-filter is leaking and opening the valve when it is not leaking. The parameters include any one or more of flow rate, flow velocity, and the duration of constant flow velocity, and configures an appropriate sensor to be electrically connected to the controller.

[0073] Step S4: The pre-filter operates in filtration mode. When the backwashing parameters reach the preset opening parameters, the drive motor rotates and the drive shaft moves axially downward to the first limit switch position. The sealing part closes the filter frame water inlet channel, and the backwashing water channel of the backwashing filter screen opens. The controller operates in backwashing mode. When the backwashing parameters reach the preset stop parameters, the drive motor reverses and the drive shaft moves axially upward to the initial position. The sealing part opens the filter frame water inlet channel, and the backwashing water channel of the backwashing filter screen closes.

[0074] Step S5: When the operating parameters of the pre-filter reach the preset valve closing parameters under leakage conditions, the drive motor rotates and the drive shaft moves axially downward to the second limit switch position, closing the water inlet port near the water inlet channel of the filter frame and the inner outlet port of the outlet port.

[0075] Step S6: When the operating parameters of the pre-filter reach the preset valve opening parameters under non-leakage conditions, the drive motor reverses and drives the transmission shaft to move axially upward to the first limit switch position to enter the backwashing mode, or directly moves axially upward to the initial position to enter the filtration mode.

[0076] The controller repeats control steps S4-S6 according to the operating status.

[0077] The beneficial effects of this invention are:

[0078] The valve head has an optimized structure, is easy to install, use and maintain. It controls the backwashing, sewage discharge and / or leakage protection valve closing action through a single motor. It has a compact structure and a high degree of automation and reliability.

[0079] This pre-filter features automatic switching between backwashing, sewage discharge, and filtration restoration modes, and / or integrates a leak-proof valve shut-off protection function, which means it can shut off the water supply in the event of a leak.

[0080] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the invention in any way. Other variations and modifications are possible without departing from the scope of the claims. For example, a manual command to close or cancel the valve can be sent to the controller, and the controller, in response, sends a running command to the drive motor 1.

Claims

1. A pre-filter with top-controlled backwashing and sewage discharge, comprising a controller, a valve head body (1) with an inlet port, an outlet port and a filter bottle assembly port, a filter bottle (14), a filter assembly disposed within the filter bottle (14) and a sewage discharge chamber disposed at the bottom of the filter bottle (14), characterized in that: It also includes drive motor components, control components, transmission components, sewage switching components, and backwashing components; The drive motor assembly includes a drive motor (2), which is fixed to the valve head body (1). The valve head body (1) is provided with an assembly cavity adapted to the output end of the drive motor (2). The control component includes a first limit switch; The transmission assembly includes a transmission shaft, which is connected to the output end of the drive motor (2) and rotates with the assembly cavity. The sewage discharge switching assembly is located at the end of the transmission shaft, and the transmission shaft can move axially under the action of the drive motor (2). The sewage switching assembly includes a sewage plug body, which includes a connecting part (31) and a functional part (32). The connecting part (31) and / or the functional part (32) are provided with a sewage discharge notch. The connecting part (31) is connected to the drive shaft. The functional part (32) is provided with at least a first sealing element (33). The sewage plug body can open or close the sewage discharge channel through the sewage discharge notch under the drive of the drive motor assembly. The backwash assembly includes a backwash frame (4), a backwash filter (6), and a sealing part. The backwash assembly is sleeved on the drive shaft and can move axially with the drive shaft under the drive of the drive motor assembly. The filter assembly includes a filter frame (10), a filter element and a filter frame inlet channel (11), and a backwash frame is inserted into the filter frame and axially slidingly sealed. When the drive shaft moves axially from the initial position to the first limit switch position, the sealing part can close the water inlet channel (11) of the filter frame, and the backwash water channel of the backwash filter (6) is opened. At the same time, the drain plug opens the drain channel of the drain chamber. When the drive shaft moves axially to the initial position, the water inlet channel (11) of the filter frame is opened, and the backwash water channel of the backwash filter (6) is closed. At the same time, the drain plug closes the drain channel of the drain chamber. The initial position is the position where the pre-filter is in the filtering state. The drive motor (2) and the first limit switch are both electrically connected to the controller. The control component also includes a second limit switch located below the first limit switch. The sealing part is provided with a first sealing part (51) and a second sealing part (52). The backwash filter screen (6) is located between the first sealing part (51) and the second sealing part (52). When the first limit switch is in position, the first sealing part (51) closes the filter frame water inlet channel (11). When the drive motor (2) drives the transmission shaft to continue running to the second limit switch position, the second sealing part (52) closes the water inlet port near the filter frame water inlet channel (11) and the inner outlet of the outlet port, thereby closing the valve. The second limit switch is electrically connected to the controller.

2. The pre-filter with top-controlled backwashing and sewage discharge according to claim 1, characterized in that: The inlet port of the valve head body (1) is also equipped with a flow sensor electrically connected to the controller. The flow sensor transmits flow data to the controller. When the flow data exceeds the set value, the controller sends a valve-closing command to the drive motor (2). After the fault is cleared, the controller receives the external command and sends a valve-opening command to the drive motor (2). Alternatively, the controller sends a valve-closing or valve-cancelling command to the controller manually. After the controller responds, it sends a running command to the drive motor (2). The flow sensor is an electromagnetic flow sensor, a vortex flow sensor, an impeller flow sensor, or an ultrasonic flow sensor.

3. The pre-filter with top-controlled backwashing and sewage discharge according to claim 1 or 2, characterized in that: The filter frame (10) is a filter mesh frame, and the filter element (12) is a filter mesh, PP cotton, or filter membrane; or the filter frame (10) is a stacked frame, and the filter element (12) is a filter stack; the controller can be connected to a remote server or user terminal via wireless communication, and the controller is provided with a remote communication unit, which includes a wireless communication module electrically connected to the circuit board of the controller.

4. The pre-filter with top-controlled backwashing and sewage discharge according to claim 3, characterized in that: The filter frame (10) is a stacked frame, the filter element (12) is a filter stack, and a stacked adjustment member (13) is provided at the lower end of the stacked frame. The stacked adjustment member (13) abuts against the filter stack. The stacked adjustment member (13) can move axially with the transmission shaft to release the abutment and loosen the filter stack or restore the abutment and press the filter stack. The controller has a processor function. The wireless communication module is any one or a combination of two of the following: 2G module, 3G module, 4G module, 5G module and WiFi module. The remote server and user terminal can receive information or remotely control the controller through the wireless communication module. At least one MCU is integrated on the circuit board of the controller. The MCU controls the operation of its electrically connected components. The wireless communication module is also integrated on the circuit board of the controller.

5. The pre-filter with top-controlled backwashing and sewage discharge according to claim 4, characterized in that: The stacked disc adjustment component (13) includes an adjustment seat and an elastic reset element. One end of the elastic reset element is fixed to the adjustment seat, and the other end can abut or be fixed to the inner wall of the bottom of the filter bottle (14). The adjustment seat and the transmission shaft can be axially fixed. When the transmission shaft moves axially downward, the elastic reset element is compressed, releasing the abutment and loosening the filter stack. When the transmission shaft moves axially upward, the elastic reset element can be reset, restoring the abutment and pressing the filter stack.

6. The pre-filter with top-controlled backwashing and sewage discharge according to claim 1 or 2, characterized in that: The diameter of the connecting part (31) is smaller than the diameter of the functional part (32). The gap between the outer periphery of the connecting part (31) and the sewage discharge chamber constitutes a sewage discharge gap. The control component also includes an initial position limit switch, which is set at the initial position and electrically connected to the controller to achieve precise reset. The first limit switch, the second limit switch and the initial limit switch are selected from any one or more of photoelectric induction switches, Hall switches and micro switches.

7. The pre-filter with top-controlled backwashing and sewage discharge according to claim 1 or 2, characterized in that: The transmission shaft includes a rotating shaft (7) and a transmission rod (8). The rotating shaft (7) is provided with an external thread, and the assembly cavity is provided with an internal thread. The rotating shaft (7) and the transmission rod (8) are detachably connected. The output shaft of the drive motor (2) is detachably connected to the rotating shaft (7). The rotating shaft (7) is sleeved with the transmission rod (8) and is provided with a snap ring assembly port for fixing by snap ring. The end of the rotating shaft (7) is provided with a special-shaped hole or special-shaped part, and the end of the drive motor output shaft is provided with a matching special-shaped part or special-shaped hole, which is connected by the cooperation of the special-shaped hole and the special-shaped part.

8. The pre-filter with top-controlled backwashing and sewage discharge according to claim 7, characterized in that: The drive motor assembly also includes a drive motor mounting base. The top of the drive motor mounting base is provided with a drive motor assembly slot. The drive motor (2) is snapped into the drive motor assembly slot. The side of the drive motor mounting base is provided with a limit switch mounting slot (9). The first limit switch, the second limit switch and the initial limit switch are fixed in the limit switch mounting slot (9). The rotating shaft (7) and the transmission rod (8) are respectively provided with limit parts. The two ends of the backwash frame (4) abut against the limit parts of the rotating shaft (7) and the transmission rod (8) respectively. The first sealing element (33) adopts an O-ring seal. The functional part (32) of the drain plug body is provided with a sealing element assembly slot. The first sealing element (33) is fixed in the sealing element assembly slot. The connecting part (31) is also provided with a drain guide groove.

9. A control method for the pre-filter according to claim 1, characterized in that: The control method steps are as follows: Step S1: Assemble the pre-filter and adjust it to the initial position. Set the controller to the initial position as the filtration mode, the first limit switch position as the backwash mode, and the second limit switch position as the valve closing mode. Step S2: The controller presets the parameters for starting and stopping the backwashing of the pre-filter. The parameters include any one or more of time, pressure, and flow rate, and configures an appropriate sensor to be electrically connected to the controller. Step S3: The controller presets parameters for closing the valve when the pre-filter is leaking and opening the valve when it is not leaking. The parameters include any one or more of flow rate, flow velocity, and the duration of constant flow velocity, and configures an appropriate sensor to be electrically connected to the controller. Step S4: The pre-filter operates in filtration mode. When the backwashing parameters reach the preset opening parameters, the drive motor rotates and the drive shaft moves axially downward to the first limit switch position. The sealing part closes the filter frame water inlet channel, and the backwashing water channel of the backwashing filter screen opens. The controller operates in backwashing mode. When the backwashing parameters reach the preset stop parameters, the drive motor reverses and the drive shaft moves axially upward to the initial position. The sealing part opens the filter frame water inlet channel, and the backwashing water channel of the backwashing filter screen closes. Step S5: When the operating parameters of the pre-filter reach the preset valve closing parameters under leakage conditions, the drive motor rotates and the drive shaft moves axially downward to the second limit switch position, closing the water inlet port near the water inlet channel of the filter frame and the inner outlet port of the outlet port. Step S6: When the operating parameters of the pre-filter reach the preset valve opening parameters under non-leakage conditions, the drive motor reverses and drives the transmission shaft to move axially upward to the first limit switch position to enter the backwashing mode, or directly moves axially upward to the initial position to enter the filtration mode. The controller repeats control steps S4-S6 according to the operating status.

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