Front filter element

Abstract

The front filter element comprises a shell, the shell comprises a water inlet connector and a water outlet connector, a filter assembly is installed in the shell, the filter assembly comprises a lining and a first filter screen, the lining comprises a first shaping pipe, the interior of the first shaping pipe is communicated with the water outlet connector, and a plurality of first through holes are formed in the side wall of the first shaping pipe; the first filter screen is arranged on the outer side of the first shaping pipe in a sleeving mode and covers the first through hole, and a first impeller capable of rotating along the axis of the first shaping pipe is arranged on the outer side of the first shaping pipe in a sleeving mode. The first impeller is arranged outside the first filter screen, and when tap water enters the shell from the water inlet connector, the impeller can be driven to rotate, so that the tap water can be quickly distributed to the peripheral side of the first filter screen, and the problem of excessive accumulation of local impurities is solved.

Description

Technical Field

[0001] The utility model relates to the technical field of filtering devices, and more specifically, to a pre-filter element. Background Art

[0002] The pre-filter is the first stage of rough filtration equipment for the whole house water supply. It can filter large particulate matters such as sediment, rust, insect eggs, and bloodworms in tap water. Generally, it is installed at the front end of the pipeline, that is, behind the water meter. Its main function is to restore tap water to the standard before leaving the factory and protect downstream equipment.

[0003] The pre-filter includes an inlet joint and an outlet joint. Tap water enters the filter from the inlet joint, passes through the filter, and then flows out from the outlet joint. The filtering structure of the pre-filter is a cylindrical filter screen. During filtration, large particulate matters in tap water can be blocked on the outer wall of the filter screen. After long-term use, more impurities will accumulate in the area of the filter screen close to the inlet joint, which is easy to be blocked, resulting in a rapid decline in the filtering effect of the pre-filter and reducing the service life of the pre-filter. Therefore, it is urgent to improve this situation. Summary of the Utility Model

[0004] The purpose of the utility model is to overcome the above-mentioned deficiencies of the prior art and provide a pre-filter element. By arranging a first impeller outside the first filter screen, when tap water enters the shell from the water inlet interface, it can drive the impeller to rotate, so as to quickly distribute the tap water to the periphery of the first filter screen, and solve the problem of excessive local impurity accumulation.

[0005] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0006] The utility model discloses a pre-filter element, which includes a shell. The shell includes a water inlet interface and a water outlet interface. A filtering component is installed inside the shell. The filtering component includes a lining and a first filter screen. The lining includes a first shaping pipe. The inside of the first shaping pipe is communicated with the water outlet interface. A plurality of first through holes are arranged on the side wall of the first shaping pipe. The first filter screen is sleeved outside the first shaping pipe and covers the first through holes. A first impeller capable of rotating along the axis of the first shaping pipe is sleeved outside the first shaping pipe.

[0007] After water enters the inside of the shell, it passes through the first impeller, the first filter screen and the first through holes, and the water passing through the first through holes flows out from the water outlet interface to form a filtering water path.

[0008] Furthermore, the first impeller includes a plurality of first blades arranged at intervals. The first blades are inclined, and the inclination angles of the plurality of first blades are the same.

[0009] Further, an annular groove is provided on the outer side of the first shaping pipe, and a convex buckle is provided on the inner wall of the first impeller. The convex buckle is inserted into the annular groove for positioning.

[0010] Further, a sewage discharge valve is provided at the lower part of the housing. The inner lining includes a second shaping pipe located above the first shaping pipe. A second through hole is provided on the outer side of the second shaping pipe. A second filter screen is sleeved on the outer side of the second shaping pipe. The second filter screen covers the second through hole. A bushing is sleeved on the outer side of the filter assembly. The upper part of the bushing is connected with a first mounting sleeve. A plurality of fourth through holes are provided on the outer side of the first mounting sleeve. The filter assembly can move up and down so that the second filter screen is located inside the first mounting sleeve and isolated from the fourth through holes, or exposed outside the first mounting sleeve and communicated with the fourth through holes. A plurality of sixth through holes are provided on the side surface of the bushing. The sixth through holes are communicated with the inside of the first shaping pipe;

[0011] After water enters the interior of the housing from the water inlet interface, a part of the water passes through the fourth through holes, the second filter screen, the interior of the inner lining, the first filter screen, the gap between the bushing and the first filter screen, and the sixth through holes, and finally flows out from the sewage discharge valve to form a first sewage discharge path. Another part of the water passes through the first impeller, the gap between the bushing and the first filter screen, and the sixth through holes, and finally flows out from the sewage discharge valve to form a second sewage discharge path.

[0012] Further, a first annular rib is provided inside the housing. The first mounting sleeve is inserted into the first annular rib and is in sealing cooperation with the inner wall of the first annular rib. A buckle sleeve is fastened and fixed to the upper part of the second shaping pipe. The upper part of the second filter screen abuts against the lower part of the buckle sleeve. The buckle sleeve is located inside the first mounting sleeve and is in sealing cooperation with the inner wall of the first mounting sleeve. A sealing ring is sleeved on the outer side of the buckle sleeve. The sealing ring is in close contact with the inner wall of the first mounting sleeve. The inner lining includes a first limiting platform located between the first shaping pipe and the second shaping pipe. A second limiting platform is provided above the fourth through hole. The first limiting platform can abut against or disengage from the second limiting platform.

[0013] Further, a bottom cover is fastened to the lower part of the first shaping pipe. A spring is installed inside the bushing. The upper end of the spring abuts against the lower part of the bottom cover and the lower end abuts against the lower surface inside the bushing.

[0014] Further, the filter assembly includes a second impeller. The second impeller is installed inside the inner lining. A plurality of second blade pieces are provided on the outer side of the second impeller. The second blade pieces are located on the side of the second through hole. The second blade pieces can drive the second impeller to rotate.

[0015] Further, the second impeller includes a sleeve. A plurality of eighth through holes are provided on the side of the sleeve. The second through hole is located on the side of the first through hole. The outer wall of the eighth through hole is in clearance fit with the inner wall of the first shaping pipe. A second annular rib is provided on the upper part of the sleeve. The diameter of the second annular rib is smaller than that of the sleeve. The second vane is located on the outer wall of the second annular rib. A plurality of seventh through holes are provided on the outer wall of the second annular rib. The seventh through hole is located below the second vane.

[0016] Further, a plurality of arc-shaped baffles are provided on the inner wall of the second shaping pipe. The baffles face the second through hole. A notch is provided between two adjacent baffles. The notch is misaligned with the second through hole. The baffle and the inner wall of the second shaping pipe form a liquid guide groove. The second through hole, the liquid guide groove and the notch are communicated.

[0017] Further, a plurality of third through holes and convex blocks are provided on the outer side of the first mounting sleeve. The third through hole is located below the fourth through hole. The third through hole is communicated with the first filter screen. The convex block is closely attached to the inner wall of the shell. A plurality of fifth through holes are provided on the outer side of the bushing located on the first filter screen. The sixth through hole is located below the fifth through hole.

[0018] The beneficial effects of the present utility model are as follows:

[0019] 1. During normal filtration, the sewage discharge valve is closed. When water passes through the first vane of the first impeller, since the first vane is inclined, the water can push the first vane, so that the first impeller rotates. When the first impeller rotates, the water flow can be dispersed, so that the water flow can more evenly fill the outer wall of the first filter screen and enter the interior of the filter assembly from the first filter screen, and finally flow out from the water outlet interface. By setting the first impeller, the problem of uneven accumulation of impurities on the outer wall of the first filter screen is effectively solved, the filtration effect is improved, the risk of blockage of the first filter screen is reduced, and the service life of the first filter screen 3 is increased;

[0020] 2. During flushing and sewage discharge, the water flow will wash the second vane after passing through the second filter screen, so as to push the second impeller to rotate. Through the rotation of the second impeller, the water flow can be evenly dispersed at the inner wall of the first filter screen, which is beneficial to improving the flushing effect of the first filter screen and effectively increasing the service life of the first filter screen. Description of the Drawings

[0021] Figure 1 It is a schematic structural diagram of the shell;

[0022] Figure 2 It is an exploded view of this embodiment;

[0023] Figure 3 It is a cross-sectional view of this embodiment in the first state;

[0024] Figure 4 is Figure 3Enlarged view at A;

[0025] Figure 5 is Figure 3 Enlarged view at B;

[0026] Figure 6 is the sectional view of this embodiment in the second state;

[0027] Figure 7 is Figure 6 Enlarged view at C;

[0028] Figure 8 is Figure 6 Enlarged view at D;

[0029] Figure 9 is the sectional view of the top view of this embodiment;

[0030] Figure 10 is the sectional view of the top view of this embodiment;

[0031] Figure 11 is the structural schematic diagram of the first impeller;

[0032] Figure 12 is the structural schematic diagram of the inner lining;

[0033] Figure 13 is the structural schematic diagram of the second impeller.

[0034] Reference numerals: 1, housing; 11, water inlet interface; 12, water outlet interface; 13, sewage valve; 14, first annular rib; 2, inner lining; 21, first shaping pipe; 22, first through hole; 23, annular groove; 24, first limiting platform; 25, second shaping pipe; 26, second through hole; 27, baffle; 28, liquid guiding groove; 29, notch; 3, first filter screen; 4, first impeller; 41, first blade; 42, convex buckle; 5, bushing; 51, first mounting sleeve; 52, third through hole; 53, fourth through hole; 54, second limiting platform; 55, fifth through hole; 56, convex block; 57, sixth through hole; 58, annular platform; 6, second filter screen; 7, second impeller; 71, sleeve; 72, second annular rib; 73, second blade; 74, seventh through hole; 75, eighth through hole; 8, buckle sleeve; 9, bottom cover; 100, spring; 200, sealing ring. Detailed implementation manners

[0035] The following will clearly and completely describe the technical solutions in the embodiments of the present utility model in conjunction with the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without creative efforts shall fall within the protection scope of the present utility model.

[0036] As Figures 1 to 3 shown, a pre-filter element includes a housing 1. The housing 1 includes a water inlet interface 11, a water outlet interface 12, and a sewage discharge valve 13. The sewage discharge valve 13 is a prior art and is installed at the lower part of the housing 1. A filter assembly is installed inside the housing 1. The filter assembly includes a lining 2 and a first filter screen 3. The lining 2 includes a first shaping tube 21. The inside of the first shaping tube 21 is communicated with the water outlet interface 12. A plurality of first through holes 22 are provided on the side wall of the first shaping tube 21. The first filter screen 3 is sleeved outside the first shaping tube 21 and covers the first through holes 22. A first impeller 4 capable of rotating along the axis of the first shaping tube 21 is sleeved outside the first shaping tube 21. The first impeller 4 includes a plurality of first blades 41 arranged at intervals. The first blades 41 are inclined. The inclination angles of the plurality of first blades 41 are the same. After water enters the inside of the housing 1, it passes through the first impeller 4, the first filter screen 3, and the first through holes 22. The water passing through the first through holes 22 flows out from the water outlet interface 12 to form a filtered water path.

[0037] During normal filtration, the sewage discharge valve 13 is closed. When water passes through the first blades 41 of the first impeller 4, since the first blades 41 are inclined, the water can push the first blades 41, so that the first impeller 4 rotates. When the first impeller 4 rotates, the water flow can be dispersed, so that the water flow can more evenly fill the outer wall of the first filter screen 3 and enter the inside of the filter assembly from the first filter screen 3, and finally flow out from the water outlet interface 12. By setting the first impeller 4, the problem of uneven accumulation of impurities on the outer wall of the first filter screen 3 is effectively solved, the filtration effect is improved, the risk of blockage of the first filter screen 3 is reduced, and the service life of the first filter screen 3 is prolonged.

[0038] As Figure 4 shown, an annular groove 23 is provided on the outer side of the first shaping tube 21. A convex buckle 42 is provided on the inner wall of the first impeller 4. The convex buckle 42 is inserted into the annular groove 23 for positioning. The first impeller 4 can move up and down within the range of the annular groove 23. Through this design, not only is it convenient for the installation of the first impeller 4 to prevent the first impeller 4 from falling off, but also the flexibility of the first impeller 4 can be improved, facilitating the rotation of the first impeller 4.

[0039] As Figures 4 to 8As shown, the inner liner 2 includes a second shaping tube 25 located above the first shaping tube 21. A second through hole 26 is provided on the outer side of the second shaping tube 25. A second filter screen 6 is sleeved on the outer side of the second shaping tube 25, and the second filter screen 6 covers the second through hole 26. A bushing 5 is sleeved on the outer side of the filtering assembly. The upper part of the bushing 5 is connected with a first mounting sleeve 51. A plurality of fourth through holes 53 are provided on the outer side of the first mounting sleeve 51. The filtering assembly can move up and down so that the second filter screen 6 is located inside the first mounting sleeve 51 and is isolated from the fourth through holes 53, or is exposed outside the first mounting sleeve 51 and is communicated with the fourth through holes 53. A plurality of sixth through holes 57 are provided on the side surface of the bushing 5, and the sixth through holes 57 are communicated with the inside of the first shaping tube 21;

[0040] After water enters the interior of the housing 1 from the water inlet interface 11, a part of the water passes through the fourth through holes 53, the second filter screen 6, the interior of the inner liner 2, the first filter screen 3, the gap between the bushing 5 and the first filter screen 3, and the sixth through holes 57, and finally flows out from the sewage discharge valve 13 to form a first sewage discharge path. Another part of the water passes through the first impeller 4, the gap between the bushing 5 and the first filter screen 3, and the sixth through holes 57, and finally flows out from the sewage discharge valve 13 to form a second sewage discharge path.

[0041] When sewage discharge is required, the water outlet interface 12 is closed and the sewage discharge valve 13 is opened. At this time, the filtering assembly moves downward so that the fourth through holes 53 are aligned with the second filter screen 6. At this time, the first sewage discharge path and the second sewage discharge path are formed. The first sewage discharge path can wash the first filter screen 3 from the inside of the inner liner 2, and the second sewage discharge path can directly wash the outer surface of the first filter screen 3. Through the two sewage discharge paths, not only can the sewage discharge operation be realized, but also the surface of the first filter screen 3 can be effectively washed, effectively reducing the risk of blockage of the first filter screen 3 and improving the service life of the first filter screen 3.

[0042] A first annular rib 14 is provided inside the housing 1. The first mounting sleeve 51 is inserted into the first annular rib 14 and is in sealing cooperation with the inner wall of the first annular rib 14. Through the cooperation of the first mounting sleeve 51 and the first annular rib 14, it can effectively ensure that the water entering from the water inlet interface 11 must pass through the filtering assembly before flowing out from the water outlet interface 12.

[0043] As Figure 4As shown, a buckle sleeve 8 is fastened and fixed to the upper part of the second shaping tube 25. The upper part of the second filter screen 6 abuts against the lower part of the buckle sleeve 8. The buckle sleeve 8 is located within the first mounting sleeve 51 and is in sealing cooperation with the inner wall of the first mounting sleeve 51. A sealing ring 200 is sleeved outside the buckle sleeve 8, and the sealing ring 200 closely adheres to the inner wall of the first mounting sleeve 51. The inner liner 2 includes a first limiting platform 24, and the first limiting platform 24 is located between the first shaping tube 21 and the second shaping tube 25. A second limiting platform 54 is provided at the upper part of the fourth through hole 53. The first limiting platform 24 can abut against or disengage from the second limiting platform 54. Through the cooperation of the buckle sleeve 8 and the first mounting sleeve 51, it can play a guiding and limiting role in the up and down movement of the filter assembly. Through the cooperation of the first limiting platform 24 and the second limiting platform 54, the limiting effect of the up and down movement of the filter assembly can be achieved, improving the reliability of the structure.

[0044] Among them, as Figure 8 shown, a bottom cover 9 is buckled to the lower part of the first shaping tube 21. A spring 100 is installed inside the bushing 5. The upper end of the spring 100 abuts against the lower part of the bottom cover 9 and the lower end abuts against the inner lower surface of the bushing 5. The lower part of the bushing 5 communicates with the sewage discharge valve 13. A ring platform 58 is provided at the lower part of the bushing 5. The bottom cover 9 can abut against the upper part of the ring platform 58. When the sewage discharge valve 13 is opened and the water outlet interface 12 is closed, the downward thrust applied to the first impeller 4 by the water flowing in from the water inlet interface 11 increases, thereby pushing the filter assembly downward and compressing the spring 100. When the sewage discharge valve 13 is closed and the water outlet interface 12 is opened, the downward thrust applied to the first impeller 4 by the water flowing in from the water inlet interface 11 decreases, the spring 100 resets, and the filter assembly rises.

[0045] As Figure 2 、 Figures 6 to 8 and Figure 13 shown, the filter assembly includes a second impeller 7. The second impeller 7 is installed inside the inner liner 2. A plurality of second vane pieces 73 are provided outside the second impeller 7. The second vane pieces 73 are located on the side of the second through hole 26. The second vane pieces 73 can drive the second impeller 7 to rotate. Specifically, the second impeller 7 includes a sleeve 71. A plurality of eighth through holes 75 are provided on the side of the sleeve 71. The second through hole 26 is located on the side of the first through hole 22. The outer wall of the eighth through hole 75 is in clearance fit with the inner wall of the first shaping tube 21. A second annular rib 72 is provided at the upper part of the sleeve 71. The diameter of the second annular rib 72 is smaller than the diameter of the sleeve 71. The second vane pieces 73 are located on the outer wall of the second annular rib 72. A plurality of seventh through holes 74 are provided on the outer wall of the second annular rib 72. The seventh through holes 74 are located below the second vane pieces 73. The upper part of the second vane pieces 73 abuts against the lower part of the buckle sleeve 8;

[0046] During filtration, after the water flow enters the interior of the inner liner 2, it enters the second impeller 7 from the eighth through-hole 75, and then flows out from the top of the second impeller 7 to the water outlet interface 12. At this time, the second impeller 7 does not rotate; during flushing and sewage discharge, the water flow will scour the second vane 73 after passing through the second filter screen 6, thereby driving the second impeller 7 to rotate. Through the rotation of the second impeller 7, the water flow can be evenly dispersed at the inner wall of the first filter screen 3, which is beneficial to improving the flushing effect of the first filter screen 3 and effectively extending the service life of the first filter screen 3.

[0047] As Figure 10 shown, a plurality of arc-shaped baffles 27 are provided on the inner wall of the second shaping tube 25. The baffles 27 face the second through-hole 26. A notch 29 is provided between two adjacent baffles 27. The notch 29 is misaligned with the second through-hole 26. The baffles 27 and the inner wall of the second shaping tube 25 form a liquid guide groove 28. The second through-hole 26, the liquid guide groove 28 and the notch 29 are communicated. During flushing and sewage discharge, after the water flow enters the interior of the liquid guide groove 28 from the second through-hole 26, due to the small size of the notch 29, the water flow pressure at the notch 29 increases, thereby being able to improve the thrust on the second vane 73 and finally being able to drive the second impeller 7 to rotate.

[0048] A plurality of third through-holes 52 and protrusions 56 are provided on the outer side of the first mounting sleeve 51. The third through-holes 52 are located below the fourth through-holes 53. The third through-holes 52 are communicated with the first filter screen 3. The protrusions 56 are closely attached to the inner wall of the housing 1. A plurality of fifth through-holes 55 are provided on the outer side of the bushing 5 located on the first filter screen 3. The sixth through-holes 57 are located below the fifth through-holes 55. By providing the third through-holes 52 and the sixth through-holes 57, the space between the bushing 5 and the housing 1 is communicated with the interior of the bushing 5, preventing water accumulation.

[0049] The above are only the preferred embodiments of the present invention. The protection scope of the present invention is not limited to the above embodiments. All technical solutions within the idea of the present invention belong to the protection scope of the present invention. It should be noted that for those of ordinary skill in the art in this technical field, several improvements and refinements made without departing from the principle of the present invention should also be regarded as within the protection scope of the present invention.

Claims

1. A pre-filter element, comprising a housing (1), wherein the housing (1) comprises a water inlet interface (11) and a water outlet interface (12), characterized in that: A filter assembly is installed inside the housing (1), the filter assembly comprising an inner liner (2) and a first filter screen (3), the inner liner (2) comprising a first shaping tube (21), the interior of the first shaping tube (21) being in communication with the water outlet interface (12), a plurality of first through holes (22) being provided on the side wall of the first shaping tube (21), the first filter screen (3) being sleeved on the outside of the first shaping tube (21) and covering the first through holes (22), and a first impeller (4) being sleeved on the outside of the first shaping tube (21) and being capable of rotating along the axis of the first shaping tube (21); After entering the housing (1), water passes through the first impeller (4), the first filter screen (3) and the first through hole (22), and the water passing through the first through hole (22) flows out from the water outlet interface (12) to form a filtering water path.

2. A pre-filter element according to claim 1, characterized in that: The first impeller (4) comprises a plurality of first impeller blades (41) arranged at intervals, the first impeller blades (41) being arranged obliquely, and the inclination angles of the plurality of first impeller blades (41) being consistent.

3. A pre-filter according to claim 1, characterized in that: An annular groove (23) is provided on the outer side of the first shaping tube (21), and a convex buckle (42) is provided on the inner wall of the first impeller (4), and the convex buckle (42) is inserted into the annular groove (23) for limiting position.

4. A pre-filter element according to claim 1, characterized in that: The lower part of the shell (1) is provided with a drain valve (13); the inner lining (2) comprises a second shaping tube (25) located at the upper part of the first shaping tube (21); the outer side of the second shaping tube (25) is provided with a second through hole (26); the outer side of the second shaping tube (25) is sleeved with a second filter screen (6); the second filter screen (6) covers the second through hole (26); the outer side of the filter assembly is sleeved with a bushing (5); the upper part of the bushing (5) is connected with a first mounting sleeve (51); the outer side of the first mounting sleeve (51) is provided with a plurality of fourth through holes (53); the filter assembly can move up and down so that the second filter screen (6) is located in the first mounting sleeve (51) and isolated from the fourth through hole (53) or the first mounting sleeve (51) is exposed and communicated with the fourth through hole (53); the side of the bushing (5) is provided with a plurality of sixth through holes (57); the sixth through holes (57) are communicated with the inside of the first shaping tube (21); After water enters the interior of the housing (1) from the water inlet interface (11), a portion of the water passes through the fourth through hole (53), the second filter screen (6), the interior of the liner (2), the first filter screen (3), the gap between the bushing (5) and the first filter screen (3), and the sixth through hole (57), and finally flows out from the sewage valve (13) to form a first sewage discharge path, and another portion of the water passes through the first impeller (4), the gap between the bushing (5) and the first filter screen (3), and the sixth through hole (57), and finally flows out from the sewage valve (13) to form a second sewage discharge path.

5. A pre-filter element according to claim 4, characterized in that: The shell (1) is provided with a first annular rib (14) inside, the first mounting sleeve (51) is inserted into the first annular rib (14) and is sealed with the inner wall of the first annular rib (14), the upper part of the second shaping tube (25) is fastened with a buckle sleeve (8), the upper part of the second filter screen (6) abuts against the lower part of the buckle sleeve (8), the buckle sleeve (8) is located in the first mounting sleeve (51) and is sealed with the inner wall of the first mounting sleeve (51), the outer side of the buckle sleeve (8) is provided with a sealing ring (200), the sealing ring (200) is tightly attached to the inner wall of the first mounting sleeve (51), the lining (2) includes a first limiting platform (24), the first limiting platform (24) is located between the first shaping tube (21) and the second shaping tube (25), the upper part of the fourth through hole (53) is provided with a second limiting platform (54), the first limiting platform (24) can abut against or detach from the second limiting platform (54).

6. A pre-filter element according to claim 4, characterized in that: The lower part of the first shaping tube (21) is buckled with a bottom cover (9), and a spring (100) is installed inside the bushing (5). The upper end of the spring (100) abuts against the lower part of the bottom cover (9) and the lower end abuts against the lower surface of the bushing (5).

7. A pre-filter element according to claim 4, characterized in that: The filter assembly comprises a second impeller (7), the second impeller (7) being installed inside the inner liner (2), a plurality of second wheel blades (73) being arranged on the outer side of the second impeller (7), the second wheel blades (73) being located on the side of the second through hole (26), and the second wheel blades (73) being able to drive the second impeller (7) to rotate.

8. A pre-filter element according to claim 7, characterized in that: The second impeller (7) comprises a sleeve (71), a side surface of the sleeve (71) is provided with a plurality of eighth through holes (75), the second through hole (26) is located on the side surface of the first through hole (22), the outer wall of the eighth through hole (75) is clearance-matched with the inner wall of the first shaping tube (21), a second annular rib (72) is provided on the upper part of the sleeve (71), the diameter of the second annular rib (72) is smaller than the diameter of the sleeve (71), the second wheel plate (73) is located on the outer wall of the second annular rib (72), the outer wall of the second annular rib (72) is provided with a plurality of seventh through holes (74), and the seventh through hole (74) is located below the second wheel plate (73).

9. A pre-filter element according to claim 7, characterized in that: The inner wall of the second shaping tube (25) is provided with a plurality of arc-shaped baffles (27), the baffles (27) are directly opposite to the second through hole (26), a notch (29) is provided between two adjacent baffles (27), the notch (29) is offset from the second through hole (26), the baffles (27) and the inner wall of the second shaping tube (25) form a liquid guide groove (28), and the second through hole (26), the liquid guide groove (28) and the notch (29) are in communication.

10. A pre-filter element according to claim 4, characterized in that: A plurality of third through holes (52) and a protrusion (56) are provided on the outside of the first mounting sleeve (51); the third through hole (52) is located below the fourth through hole (53); the third through hole (52) is connected to the first filter screen (3); the protrusion (56) is in close contact with the inner wall of the shell (1); the bushing (5) is located on the outside of the first filter screen (3); and a plurality of fifth through holes (55) are provided; the sixth through hole (57) is located below the fifth through hole (55).

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