Pre-filter with top-controlled backwash function

Abstract

The present invention relates to a pre-filter with a top-controlled backwashing function, which comprises: a machine head with a water inlet and a water outlet, a filter bottle with a closable sewage discharge part matched with the machine head, a filtering and backwashing mechanism is arranged inside the filter bottle, a raw water chamber is formed by the gap between the outside of the filtering and backwashing mechanism and the filter bottle, a purified water chamber is formed inside the filtering and backwashing mechanism, and the filtering and backwashing mechanism comprises a filtering element and a backwashing element arranged coaxially, the raw water chamber can be connected with the water inlet of the filtering element, the purified water chamber is connected with the water outlet, the backwashing element can be driven axially by an external force relative to the filtering element, the backwashing element is fixedly mechanically connected with the external force output mechanism, and the external force output mechanism is arranged at the top of the machine head. The present invention has a reasonable structural design, is easy to assemble, and can achieve backwashing by switching the flow channel.

Description

Technical Field

[0001] The invention relates to a pre-filter with a top-controlled backwashing function, belonging to the technical field of water treatment and purification equipment. Background Art

[0002] The pre-filter in the prior art includes: a machine head, a filter bottle connected to the machine head at the upper end, a drainage seal connected to the lower end of the filter bottle, and a drainage ball valve connected to the drainage seal. A filter screen frame is arranged in the filter bottle, and a filter screen is sleeved on the outer wall of the filter screen frame. During use, water flows from the water inlet of the machine head into the gap between the filter bottle and the filter screen, flows into the center of the filter screen frame after being filtered by the filter screen, and then flows from the center of the filter screen frame to the water outlet of the machine head.

[0003] With this pre-filter, drinking water from a drinking water supply can be filtered before it is used at the tap. Impurities accumulated in the filter gradually clog the filter. This causes an undesirable pressure drop. This affects the service life of the pre-filter. In the prior art, manual disassembly and cleaning is inefficient and easy to damage the components. Therefore, it is necessary to design a pre-filter assembly that can be backwashed. By switching the flow channel and backwashing, a water flow in the opposite direction is generated through the filter to re-clean the filter. The water that receives impurities during the backwashing process is discharged through the drain ball valve.

[0004] The present invention aims to solve this technical problem and provides a pre-filter with a top-controlled backwashing function. Summary of the invention

[0005] One of the purposes of the present invention is to solve the deficiencies of the prior art and provide a pre-filter with a top controlled backwashing function.

[0006] The technical solution adopted by the present invention to solve the technical problem is:

[0007] A pre-filter with a top-controlled backwashing function comprises: a machine head with a water inlet and a water outlet, a filter bottle with a closable sewage discharge part matched with the machine head, a filtering and backwashing mechanism is arranged inside the filter bottle, a raw water chamber is constituted by a gap between the outside of the filtering and backwashing mechanism and the filter bottle, a purified water chamber is constituted inside the filtering and backwashing mechanism, the filtering and backwashing mechanism comprises a filtering element and a backwashing element arranged coaxially, the raw water chamber is connectable with the water inlet of the filtering element, the purified water chamber is connected with the water outlet, the backwashing element can be driven axially by an external force relative to the filtering element to realize the switching of the filtering function and the backwashing function, the backwashing element is fixedly mechanically connected to the external force output mechanism, and the external force output mechanism is arranged on the top of the machine head.

[0008] Preferably, the filter element is composed of a filter body, a filter frame, and a water inlet end cap and a water discharge end cap located at both ends of the filter frame, the outer size of the water inlet end cap is adapted to the upper end of the filter bottle, the water inlet end cap is connected to the inlet of the machine head, and a raw water cavity is formed between the filter body and the filter bottle;

[0009] The backwashing element comprises a backwashing filter body, a backwashing filter frame and a backwashing filter lower seal with a drainage channel. The backwashing filter body is sleeved on the assembly part of the backwashing filter frame, placed in the backwashing filter body assembly cavity in the machine head and sealed at both ends. The backwashing filter lower seal passes through the drainage end cover and is detachably connected to the backwashing filter frame. The drainage end cover is circumferentially sealed with the lower end of the backwashing filter frame. The backwashing filter frame can move axially relative to the filter element synchronously with the backwashing filter body.

[0010] After a certain downward axial movement, the lower working surface of the assembly part can close the water inlet cover, and the backwash filter body leaks out, realizing the flow channel switching and entering the backwash working mode;

[0011] After a certain upward axial movement, the lower working surface of the assembly part opens the water inlet cover, the backwash filter body is closed, the flow channel is switched, and the filtering working mode is entered.

[0012] Preferably, the external force output mechanism includes: a drive shaft and a manual drive knob fixed to its end, a drive shaft assembly cavity is provided on the top of the machine head, the drive shaft is threadedly connected to the machine head and can be sealed, the drive shaft extends into the backwash filter skeleton, and abuts against the backwash filter lower seal in the backwash filter skeleton, and can drive the backwash filter skeleton and the backwash filter lower seal to move axially and rotate together.

[0013] Preferably, the manual drive knob comprises a knob body and a positioning piece, the knob body is sleeved on the positioning piece and is detachably connected to the end of the drive shaft, and the positioning piece is threadedly fixed to the assembly cavity of the drive shaft.

[0014] Preferably, the external force output mechanism includes: a drive shaft, a drive motor connected to its end and an axial stroke control mechanism. A drive shaft assembly cavity is provided on the top of the machine head. The drive shaft is threaded and sealed to the machine head. The drive shaft extends into the backwash filter frame and abuts against the backwash filter lower seal in the backwash filter frame. It can drive the backwash filter frame and the backwash filter lower seal to move and rotate axially together. The forward and reverse rotation of the drive motor is controlled by the axial stroke control mechanism, thereby driving the axial movement stroke of the drive shaft. The axial stroke control mechanism includes a limit switch.

[0015] Preferably, a first limiter is provided in the backwash filter frame, and a matching second limiter is provided on the drive shaft, and the axial displacement stroke of the drive shaft is controlled by the cooperation of the first and second limiters.

[0016] Preferably, a backwash water distribution member for generating a larger flow rate with a smaller flow diameter is provided in the backwash element. The backwash water distribution member is sleeved on the drive shaft and has a relatively fixed axial position and can rotate around the drive shaft.

[0017] Preferably, the sewage discharge part of the filter bottle is provided with a cavity with a gradually decreasing diameter in the middle part and a gradually increasing diameter at both ends; in the filtering state, the outer edge of the end of the lower seal of the backwashing filter cooperates with the smallest diameter part to realize the sealing of the sewage discharge part, and when switching to the backwashing state, the lower seal of the backwashing filter moves downward under the action of external force and enters the part with gradually increasing diameter, and a sewage discharge channel is formed between the lower seal of the backwashing filter and the cavity, and the sewage discharge part is opened; at least the outer edge of the end of the lower seal of the backwashing filter has elastic deformation and reset functions.

[0018] Preferably, the backwash water distribution member is provided with a plurality of nozzles which can spray water in a tangential direction. Preferably, the nozzles of the backwash water distribution member are staggered in an axial direction.

[0019] Preferably, the filter element is further provided with a directional cleaning assembly on the outside, including a flow guide and an adjustment member, the flow guide comprising at least one flow guide groove extending along the axial direction of the filter element and an assembly seat fixed to the flow guide groove and capable of matching the shape of the bottom of the filter element, the assembly seat is provided with an assembly hole, and is sleeved on the lower seal of the backwashing filter screen through the assembly hole, and at least one stopper is also provided at the bottom of the assembly seat;

[0020] The adjusting member is provided with an assembly hole and a cavity adapted to the assembly seat, and is sleeved on the lower seal of the backwashing filter through the assembly hole and can rotate synchronously, and at least one limiting groove is provided on the edge of the cavity, and at least one through hole is provided on the side of the cavity;

[0021] When the lower seal of the backwash filter moves downward and rotates, the adjusting member is driven, and then the flow guide member is driven to rotate circumferentially around the filter element. The backwash water is discharged through the through hole and the sewage discharge channel, so that large particles of impurities are discharged by backwashing.

[0022] During the upward rotation and resetting process of the lower seal of the backwash filter, the adjustment part and the guide part are misaligned, the through hole of the adjustment part is closed, and the backwash water enters the sewage discharge channel along the gap between the guide part and the adjustment part and is discharged, realizing negative pressure directional backwashing.

[0023] Preferably, the drive shaft adopts a split design, including an upper drive shaft and a lower drive shaft, the upper drive shaft is threadedly connected to the machine head, and the lower drive shaft is detachably connected to the upper drive shaft.

[0024] The beneficial effects of the present invention are as follows: the present invention has a reasonable structural design, is easy to assemble, and can achieve backwashing by switching the flow channel. In the filtering working state, water enters the interior from the outside of the filter body through the water inlet end cover through the raw water cavity from the inlet of the machine head, and impurities are intercepted by the filter body. The purified water entering the interior flows through the backwashing filter frame and flows from the top of the sealing cover to the outlet of the machine head; in the backwashing working state, the driving shaft is driven downward through the external force output mechanism, the backwashing element is driven downward, the backwashing filter body leaks out of the sealing cover, the lower working surface of the assembly part of the backwashing filter frame closes the water inlet end cover, and the sewage discharge part is opened at the same time to achieve flow channel switching. The inlet water flows out from the inside after being filtered by the backwashing filter body, and the filter body is backwashed. The impurity-containing water of the backwashing flows out through the drainage channel of the lower seal of the backwashing filter and is discharged through the sewage discharge part. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a stereogram of a pre-filter of the present invention;

[0026] Figure 2 is an exploded view of the pre-filter of the present invention;

[0027] Figure 3 It is a schematic diagram of the assembly of the pre-filter of the present invention;

[0028] Figure 4 is a cross-sectional view of the pre-filter of the present invention in a filtering state;

[0029] Figure 5 is a cross-sectional view of the pre-filter of the present invention in a backwashing state;

[0030] Figure 6 This is the main view of the pre-filter of Example 2 of the present invention;

[0031] Figure 7 is an exploded view of the pre-filter of Example 2 of the present invention;

[0032] Figure 8 It is a cross-sectional view of the pre-filter of Example 2 of the present invention.

[0033] In the figure: 1, head, 2, sewage discharge part, 3, filter bottle, 4, filter element, 41, filter body, 42, filter frame, 43, water inlet end cover, 44, drainage end cover, 5, backwashing element, 51, backwashing filter body, 52, backwashing filter frame, 52a, assembly part, 53, backwashing filter body assembly cavity, 54, backwashing filter lower seal, 6, drive shaft, 61, touch part, 6a, upper drive shaft, 6b, lower drive shaft, 7, manual drive knob, 7a, knob body, 7b, positioning piece, 8, backwash water distribution piece, 8a, nozzle, 9, cavity, 10, directional cleaning component, 11, guide piece, 11a, guide groove, 11b, assembly seat, 11c, limit piece, 12, adjustment piece, 12a, limit groove, 12b, through hole, 13, drive motor, 14, limit switch, 15, fixing seat, 16, protective cover. DETAILED DESCRIPTION

[0034] The technical solution of the present invention is further described in detail below through specific embodiments in conjunction with the accompanying drawings. Example

[0035] like Figure 1 and Figure 3 As shown, a pre-filter with a top-controlled backwashing function comprises: a machine head 1 with a water inlet and a water outlet, a filter bottle 3 with a closable sewage discharge part 2 cooperating with the machine head 1, a filtering and backwashing mechanism is arranged inside the filter bottle 3, a raw water cavity is constituted by a gap between the outside of the filtering and backwashing mechanism and the filter bottle 3, and a purified water cavity is constituted inside the filtering and backwashing mechanism, the filtering and backwashing mechanism comprises a filtering element 4 and a backwashing element 5 arranged coaxially, the raw water cavity is able to communicate with the water inlet of the filtering element 4, and the purified water cavity is connected with the water outlet, the backwashing element 5 can be driven axially relative to the filtering element 4 by an external force, the backwashing element 5 is fixedly mechanically connected to the external force output mechanism, and the external force output mechanism is arranged on the top of the machine head 1.

[0036] Specifically to the present invention, Figure 2 As shown, the filter element 4 is composed of a filter body 41, a filter frame 42, and a water inlet end cap 43 and a water discharge end cap 44 located at both ends of the filter frame 42. The external size of the water inlet end cap 43 is adapted to the part that matches the upper end of the filter bottle 3. The water inlet end cap 43 is connected to the inlet of the machine head 1, and a raw water cavity is formed between the filter body 41 and the filter bottle 3.

[0037] The backwashing element 5 comprises a backwashing filter body 51, a backwashing filter frame 52 and a backwashing filter lower seal 54 with a drainage channel. The backwashing filter body 51 is sleeved on the assembly part 52a of the backwashing filter frame 52, and is placed in the backwashing filter body assembly cavity 53 in the machine head 1 and sealed at both ends. The backwashing filter lower seal 54 passes through the drainage end cover 44 and is detachably connected (sleeved or abutted) with the backwashing filter frame 52. The drainage end cover 44 is circumferentially sealed with the lower end of the backwashing filter frame 52. The backwashing filter frame 52 can move axially relative to the filter element 4 synchronously with the backwashing filter body 51.

[0038] When moving axially downward, in the backwash filtering state, the lower working surface of the assembly part 52a can close the water inlet end cover 43, the backwash filter body 51 leaks out, and the water at the water inlet of the head 1 can pass through the backwash filter body 51, realizing the flow channel switching and entering the backwash working mode.

[0039] After a certain upward axial movement, the lower working surface of the assembly portion 52a opens the water inlet end cover 43, and the backwashing filter body 51 is closed, so that the flow channel is switched and the filtering working mode is entered.

[0040] Specifically to the present invention, Figure 2 As shown, the external force output mechanism includes: a drive shaft 6 and a manual drive knob 7 fixed to its end, a drive shaft 6 assembly cavity is provided on the top of the machine head 1, the drive shaft 6 is threadedly connected to the machine head 1 and can be sealed, the drive shaft 6 extends into the backwashing filter skeleton 52, and abuts against the backwashing filter lower seal 54 in the backwashing filter skeleton 52, and can drive the backwashing filter skeleton 52 and the backwashing filter lower seal 54 to move axially and rotate together.

[0041] In order to avoid accidental separation of the drive shaft 6 and the head 1, the manual drive knob 7 includes a knob body 7a and a positioning member 7b. The knob body 7a is sleeved on the positioning member 7b and is detachably connected to the end of the drive shaft 6 (polygonal snap-in limit is one means of implementation), and the positioning member 7b is threadedly connected to the drive shaft assembly cavity.

[0042] More specifically, a first limiter is provided in the backwashing filter frame 52, and a matching second limiter is provided on the drive shaft 6, and the axial displacement stroke of the drive shaft 6 is controlled by the cooperation of the first and second limiters.

[0043] In order to achieve a better backwashing effect, a backwashing water distribution member 8 is provided in the backwashing element 5 to generate a larger flow rate with a smaller flow diameter. The backwashing water distribution member 8 is sleeved on the drive shaft 6 and has a relatively fixed axial position and can rotate around the drive shaft 6 .

[0044] In the present invention, Figure 4 and Figure 5As shown, the sewage discharge part 2 of the filter bottle 3 is provided with a cavity 9 with a gradually decreasing diameter in the middle part and a gradually increasing diameter at both ends; in the filtering state, the outer edge of the end of the lower seal 54 of the backwashing filter cooperates with the smallest diameter part to achieve sealing of the sewage discharge part 2, and when switching to the backwashing state, the lower seal 54 of the backwashing filter moves downward under the action of external force and enters the part with gradually increasing diameter, and a sewage discharge channel is formed between the lower seal 54 of the backwashing filter and the cavity 9, and the sewage discharge part 2 is opened; at least the outer edge of the end of the lower seal 54 of the backwashing filter has elastic deformation and reset functions, and through elastic deformation and reset, it can realize both the closing function and the opening function.

[0045] In the present invention, in order to achieve a better backwash water distribution effect, the backwash water distribution member 8 is provided with a plurality of nozzles 8a, which can spray water along the tangential direction. Preferably, the nozzles 8a of the backwash water distribution member 8 are staggered along the axial direction.

[0046] In order to further realize negative pressure directional backwashing and improve the backwashing effect, the filter element 4 is further provided with a directional cleaning assembly 10 on the outside, including a guide member 11 and an adjustment member 12. The guide member 11 includes at least one guide groove 11a extending along the axial direction of the filter element 4 and an assembly seat 11b fixed to the guide groove 11a and capable of matching the shape of the bottom of the filter element 4. The assembly seat 11b is provided with an assembly hole, and is sleeved on the backwashing filter lower seal 54 through the assembly hole. At least one stopper 11c is also provided at the bottom of the assembly seat 11b;

[0047] The adjusting member 12 is provided with an assembly hole and a cavity adapted to the assembly seat 11b, and is sleeved on the lower seal 54 of the backwashing filter through the assembly hole and can rotate synchronously, and at least one limiting groove 12a is provided on the edge of the cavity, and at least one through hole 12b is provided on the side of the cavity;

[0048] When the lower seal 54 of the backwash filter moves downward in the axial direction and rotates, the adjusting member 12 is driven, and then the flow guide member 11 is driven to rotate circumferentially around the filter element 4, and the backwash water is discharged through the through hole 12b and the sewage discharge channel, so that large particles of impurities are discharged by backwashing;

[0049] During the upward rotation and resetting process of the lower seal 54 of the backwash filter, the adjusting member 12 and the guide member 11 are misaligned, the through hole 12b of the adjusting member 12 is closed, and the backwash water enters the sewage discharge channel along the gap between the guide member 11 and the adjusting member 12 and is discharged, realizing negative pressure directional backwashing.

[0050] Specifically to the present invention, for the convenience of processing and better adaptation, the drive shaft 6 adopts a split design, including an upper drive shaft 6a and a lower drive shaft 6b. The upper drive shaft 6a is screwed to the machine head 1, and the lower drive shaft 6b is detachably connected to the upper drive shaft 6a (such as snap-on or screwed). The split design also has the following advantages: the upper drive shaft 6a can be made larger in size to match the size of the machine head 1, and the lower drive shaft 6b can be made smaller in size to ensure that the space in the backwash element 5 is not occupied too much. Example

[0051] like Figure 6-8 As shown, as an alternative, the other structures are basically the same as those in Example 1, except that the external force output mechanism includes: a drive shaft 6, a drive motor 13 connected to its end, and an axial stroke control mechanism. A drive shaft assembly cavity is provided at the top of the machine head 1, and the drive shaft 6 is screwed and sealed with the machine head 1. The drive shaft 6 extends into the backwashing filter frame 52 and abuts against the backwashing filter lower seal 54 in the backwashing filter frame 52, and can drive the backwashing filter frame 52 and the backwashing filter lower seal 54 to move and rotate axially together. The forward and reverse rotation of the drive motor 13 is controlled by the axial stroke control mechanism (such as the limit switch 14), thereby driving the axial movement stroke of the drive shaft 6. Specifically, there are two limit switches 14, namely, an upper limit switch and a lower limit switch, wherein the upper and lower limit switches are assembled on the fixing seat 15, and the drive motor 13 is also detachably connected (screwed or clamped) with a protective cover 16 on the outside, and the assembly spacing of the upper and lower limit switches meets the axial stroke requirements. The operation of the upper and lower limit switches 14 is controlled by the triggering portion 61 disposed on the driving shaft 6 .

[0052] The above-described embodiment is only a preferred solution of the present invention and does not limit the present invention in any form. There are other variations and modifications without exceeding the technical solution described in the claims.

Claims

1. A pre-filter with top-controlled backwashing function, comprising: A machine head with a water inlet and a water outlet, a filter bottle with a closable sewage discharge part matched with the machine head, a filtering and backwashing mechanism is arranged inside the filter bottle, a raw water chamber is formed by the gap between the outside of the filtering and backwashing mechanism and the filter bottle, and a purified water chamber is formed inside the filtering and backwashing mechanism, the filtering and backwashing mechanism comprises a filtering element and a coaxially arranged backwashing element, the raw water chamber is able to communicate with the water inlet of the filtering element, and the purified water chamber is communicated with the water outlet, the filtering element is composed of a filter screen body, a filter screen frame, and a water inlet end cap and a drainage end cap located at both ends of the filter screen frame, the external dimensions of the water inlet end cap are adapted to the upper end of the filter bottle, and the raw water chamber is communicated with the inlet of the machine head through the water inlet end cap; The backwashing element comprises a backwashing filter body, a backwashing filter frame and a backwashing filter lower seal with a drainage channel. The backwashing filter body is sleeved on the assembly part of the backwashing filter frame, placed in the backwashing filter body assembly cavity in the machine head and sealed at both ends. The backwashing filter lower seal passes through the drainage end cover and is detachably connected to the backwashing filter frame. The drainage end cover is circumferentially sealed with the lower end of the backwashing filter frame. It is characterized in that the backwashing element can be driven by external force to move axially relative to the filter element to achieve the switching of the filtering function and the backwashing function. After a certain downward axial movement, the lower working surface of the assembly part can close the water inlet cover, and the backwash filter body leaks out, realizing the flow channel switching and entering the backwash working mode; After a certain upward axial movement, the lower working surface of the assembly part opens the water inlet cover, the backwash filter body is closed, the flow channel is switched, and the filtering working mode is entered; The backwash element is fixedly connected to the external force output mechanism, and the external force output mechanism is arranged on the top of the machine head; the external force output mechanism comprises: a drive shaft and a manual drive knob fixed to the end thereof; A drive shaft assembly cavity is provided on the top of the machine head. The drive shaft is threadedly connected to the machine head and can be sealed. The drive shaft extends into the backwash filter frame and abuts against the backwash filter lower seal body in the backwash filter frame. The drive shaft can drive the backwash filter frame and the backwash filter lower seal body to move axially and rotate together through the action of a manual drive knob.

2. A pre-filter with top-controlled backwashing function, comprising: A machine head with a water inlet and a water outlet, a filter bottle with a closable sewage discharge part matched with the machine head, a filtering and backwashing mechanism is arranged inside the filter bottle, a raw water chamber is formed by the gap between the outside of the filtering and backwashing mechanism and the filter bottle, and a purified water chamber is formed inside the filtering and backwashing mechanism, the filtering and backwashing mechanism comprises a filtering element and a coaxially arranged backwashing element, the raw water chamber is able to communicate with the water inlet of the filtering element, and the purified water chamber is communicated with the water outlet, the filtering element is composed of a filter screen body, a filter screen frame, and a water inlet end cap and a drainage end cap located at both ends of the filter screen frame, the external dimensions of the water inlet end cap are adapted to the upper end of the filter bottle, and the raw water chamber is communicated with the inlet of the machine head through the water inlet end cap; The backwashing element comprises a backwashing filter body, a backwashing filter frame and a backwashing filter lower seal with a drainage channel. The backwashing filter body is sleeved on the assembly part of the backwashing filter frame, placed in the backwashing filter body assembly cavity in the machine head and sealed at both ends. The backwashing filter lower seal passes through the drainage end cover and is detachably connected to the backwashing filter frame. The drainage end cover is circumferentially sealed with the lower end of the backwashing filter frame. It is characterized in that the backwashing element can be driven by external force to move axially relative to the filter element to achieve the switching of the filtering function and the backwashing function. After a certain downward axial movement, the lower working surface of the assembly part can close the water inlet cover, and the backwash filter body leaks out, realizing the flow channel switching and entering the backwash working mode; After a certain upward axial movement, the lower working surface of the assembly part opens the water inlet cover, the backwash filter body is closed, the flow channel is switched, and the filtering working mode is entered; The backwashing element is fixedly mechanically connected to the external force output mechanism, and the external force output mechanism is arranged at the top of the machine head; the external force output mechanism includes: a drive shaft, a drive motor connected to its end and an axial stroke control mechanism, a drive shaft assembly cavity is provided on the top of the machine head, the drive shaft is threaded and sealed with the machine head, the drive shaft extends into the backwashing filter frame, abuts against the backwashing filter lower seal in the backwashing filter frame, can drive the backwashing filter frame and the backwashing filter lower seal to move and rotate axially together, the forward and reverse rotation of the drive motor is controlled by the axial stroke control mechanism, and then the axial movement stroke of the drive shaft is driven, and the axial stroke control mechanism includes a limit switch.

3. The pre-filter with top-controlled backwashing function according to claim 1, characterized in that: The manual driving knob comprises a knob body and a positioning piece. The knob body is sleeved on the positioning piece and is detachably connected to the end of the driving shaft. The positioning piece is threadedly fixed to the driving shaft assembly cavity.

4. The pre-filter with top-controlled backwashing function according to claim 1 or 2, characterized in that: A first limiting member is provided in the backwashing filter frame, and a matching second limiting member is provided on the driving shaft. The axial displacement stroke of the driving shaft is controlled by the cooperation of the first and second limiting members.

5. The pre-filter with top-controlled backwashing function according to claim 1 or 2, characterized in that: The backwash element is provided with a backwash water distribution member that produces a larger flow rate with a smaller flow diameter. The backwash water distribution member is sleeved on the drive shaft and has a relatively fixed axial position and can rotate around the drive shaft. The backwash water distribution member is provided with a plurality of nozzles that can spray water along the tangential direction.

6. The pre-filter with top-controlled backwashing function according to claim 5, characterized in that: The nozzles of the backwash water distribution member are staggered in the axial direction.

7. The pre-filter with top-controlled backwashing function according to claim 1 or 2, characterized in that: The sewage discharge part of the filter bottle is provided with a cavity with a gradually decreasing diameter in the middle part and a gradually increasing diameter at both ends; in the filtering state, the outer edge of the end of the lower seal of the backwashing filter cooperates with the smallest diameter part to realize the sealing of the sewage discharge part, and when switching to the backwashing state, the lower seal of the backwashing filter moves downward under the action of external force and enters the part with gradually increasing diameter, and a sewage discharge channel is formed between the lower seal of the backwashing filter and the cavity, and the sewage discharge part is opened; at least the outer edge of the end of the lower seal of the backwashing filter has elastic deformation and reset functions.

8. The pre-filter with top-controlled backwashing function according to claim 1 or 2, characterized in that: The filter element is also provided with a directional cleaning assembly outside, including a flow guide and an adjustment member, the flow guide includes at least one flow guide groove extending along the axial direction of the filter element and an assembly seat fixed to the flow guide groove and capable of matching the shape of the bottom of the filter element, the assembly seat is provided with an assembly hole, and is sleeved on the lower seal of the backwashing filter screen through the assembly hole, and at least one stopper is also provided at the bottom of the assembly seat; The adjusting member is provided with an assembly hole and a cavity adapted to the assembly seat, and is sleeved on the lower seal of the backwashing filter through the assembly hole and can rotate synchronously, and at least one limiting groove is provided on the edge of the cavity, and at least one through hole is provided on the side of the cavity; When the lower seal of the backwash filter moves downward and rotates, the adjusting member is driven, and then the flow guide member is driven to rotate circumferentially around the filter element. The backwash water is discharged through the through hole and the sewage discharge channel, so that large particles of impurities are discharged by backwashing. During the upward rotation and resetting process of the lower seal of the backwash filter, the adjustment part and the guide part are misaligned, the through hole of the adjustment part is closed, and the backwash water enters the sewage discharge channel along the gap between the guide part and the adjustment part and is discharged, realizing negative pressure directional backwashing.

9. The pre-filter with top-controlled backwashing function according to claim 1 or 2, characterized in that: The drive shaft adopts a split design, including an upper drive shaft and a lower drive shaft, the upper drive shaft is screwed to the machine head, and the lower drive shaft is detachably connected to the upper drive shaft.

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