A filter element and a slit-type self-cleaning filter using the filter element

Abstract

A filter element and a slit-type self-cleaning filter using the same filter element belong to the technical field of filters, and particularly relate to a filter element and a slit-type self-cleaning filter using the same filter element. The present invention provides a filter element and a slit-type self-cleaning filter using the same filter element with reasonable structure, not limited by the caliber, and simple manufacturing process. The filter element of the slit-type self-cleaning filter of the present invention includes a top fixing plate, a bottom fixing plate and a filter sheet group, and is characterized in that: connection hole groups are arranged on the circumference of the filter sheet body of the filter sheet group, and the filter sheet group is fixed between the top fixing plate and the bottom fixing plate through connecting shafts in the connection hole groups; a filter sheet gap is arranged between adjacent two filter sheet bodies of the filter sheet group through a filter spacer.

Description

Technical Field

[0001] The present invention belongs to the technical field of filters, and particularly relates to a filter element and a slit-type self-cleaning filter using the filter element. Background Art

[0002] In actual production and life, when a liquid contains particulate matter of a certain particle size, a porous or slotted mesh material is required to filter out larger particles. During the filtration process, the filter mesh will inevitably become blocked. Currently, most filters use backwashing or disassembling the filter to clean the filter mesh to improve the blockage situation. Both of these methods are time-consuming and laborious. Especially in the filtration of high-viscosity liquids, the cleaning process is more difficult and will also affect the continuous operation of the in-line filter. To achieve the continuous operation of the filter online, one standby unit is required, which will inevitably increase the cost.

[0003] Since the slit-type filter uses the gap formed between circular filter discs for filtration, it can achieve online cleaning without the need to add additional flushing devices and without stopping the machine. Existing slit-type filters, such as Figure 1 and Figure 2 shown, mainly consists of a filter body 5 for flow distribution, a filter element part, a cleaning part, a housing 1, a handwheel 6, and a drain valve 13. The filter element part and the cleaning part are the core of the entire filter. The filter element part consists of a drive shaft 7, filter discs 3, and filter spacers 4; while the cleaning part consists of a cleaning blade 8, a cleaning washer 9, a support shaft 10, and a support shaft 2. The filter element part and the cleaning part of the existing slit-type filter share a bottom plate 11, and the bottom plate 11 serves two functions of closing and fixing at the bottom of the filter element.

[0004] The working principle of the slit-type filter is as follows: As shown by the arrows in Figure 1 , the liquid enters the outer cavity of the housing 1 and the filter element through the inlet. Under the action of pressure, the liquid flows into the inner cavity of the filter element through the gaps between the filter discs 3 separated by the filter spacers 4. Particles and impurities larger than this gap are separated outside the filter element. The clean liquid flows through the inner cavity of the filter element and then flows out through the outlet. Due to long-term operation, most of the particles and impurities separated outside the filter element precipitate towards the bottom of the housing 1, while a small part of the dirt and impurities will gradually adsorb between the outer side of the filter element and the filtration gap, which will cause the filter element to become blocked and the flow rate to decrease. At this time, according to the change in the inlet and outlet pressures, cleaning work needs to be carried out. Rotate the handwheel 6, drive the filter discs 3 to rotate through the drive shaft 7, and the cleaning blade 8 scrapes out the impurities in the gap and relies on the filtered liquid itself for flushing to achieve self-cleaning of the filter element. Open the drain valve 13 to discharge the impurities, so that the filter element can continue to work normally.

[0005] Since existing slit-type filters all adopt the structure shown in Figure 1 , the structural diagrams of the filter discs 3 and the filter spacers 4 are respectively as shown inFigure 3 and Figure 4 As shown in Figure 4 , the structural diagram of the cleaning blade 8 is as follows Figure 5 shown, combined with Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5 , and its assembly process is as follows: A certain number of filter plates 3 and filter spacers 4 are installed on the transmission shaft 7, and the transmission shaft 7 is supported in the holes of the filter body 5; A certain number of cleaning blades 8 and cleaning washers 9 are installed on the support shaft 10, and then it is installed in a threaded hole of the filter body 5. In order to make this cleaning part more stable, two threaded holes are set on the filter body 5 and two support shafts 2 are installed. There is a large hole in the center of the bottom plate 11, and three small holes are radially distributed. The transmission shaft 7 passes through the large hole in the center, and the support shaft 10 and the two support shafts 2 pass through the three small holes respectively, and then are fastened by the nut 12. In order to enable the transmission shaft 7 to drive the filter plates 3 and the filter spacers 4 to rotate, the cross-section of the transmission shaft 7 needs to be milled to be D-shaped, and D-shaped holes are also machined in the centers of the filter plates 3 and the filter spacers 4; In order to prevent the cleaning blade 8 from rotating on the support shaft 10, the cross-section of the support shaft 10 also needs to be milled to be D-shaped, and a D-shaped hole is also machined in the middle of the cleaning blade 8.

[0006] The gap between the filter plates 3, that is, the thickness of the filter spacer 4, is the filtration accuracy. The filtration accuracy of each filter is generally between 0.1 mm and 5 mm according to user requirements, and this value can also be larger in some cases. And for the filter plate 3 and the cleaning blade 8 to achieve relative rotation, there also needs to be a very small axial gap between them. Using Figure 3 this shape of filter plate, as can be seen from Figure 1 , the fastening of the filter plate 3 and the fastening of the cleaning blade 8 are both completed by a nut 12 under the bottom plate 11, which makes the existing such filters have the following defects.

[0007] 1. Figure 3 It is difficult to obtain a stable filtration accuracy for this shape of filter plate 3. Because it is only fastened at a hole in the middle of the filter plate 3, it will inevitably cause the warping of the filter plate, which is obviously a problem caused by only one filter spacer 4 being supported at a single point in the center. To overcome this defect, existing filters mostly use a filter spacer 4 with four protruding parts as shown in Figure 4 , but since the fastening force of the nut 12 acting on the axis of the transmission shaft 7 is already very small at the four protrusions, the problem cannot be fundamentally solved. Similarly, for the cleaning blade 8 as shown in Figure 5 , there is also only one fastening hole, and the same problem exists.

[0008] 2. Another greater defect brought about by the above problem 1 is that Figure 3The diameter of the filter element in this shape cannot be too large. The diameters of the filter elements of existing slit-type filters are all below 56 mm, which limits the filtering area of the filter element. Therefore, the existing slit-type filters with a caliber above 50 cannot be realized.

[0009] 3. Figure 1 For the filter shown, the filter element part and the cleaning part share a bottom plate 11, and a nut 12 in the middle is used to fasten both the filter sheet 3 and the cleaning blade 8 at the same time. It is difficult to ensure the proper clearance for relative rotation between the two, which will also affect the stability of the filtering clearance. This structure is unreasonable.

[0010] 4. The cross-sections of the transmission shaft 7 and the support shaft 10 need to be machined into a D shape. Milling a long strip plane on a slender shaft is also time-consuming and laborious. The process is unreasonable.

[0011] In summary, the filter element part and the cleaning part are the core components of the slit-type filter. Designing a filter element and a filter with a new structure can fundamentally solve the above problems. Summary of the Invention

[0012] The present invention aims at the above problems and provides a filter element with a reasonable structure, not limited by the caliber, and a simple manufacturing process, and a slit-type self-cleaning filter using the filter element.

[0013] To achieve the above object of the present invention, the present invention adopts the following technical solutions. The filter element of the slit-type self-cleaning filter of the present invention includes a top fixing member, a bottom closing member, and a filter sheet group. It is characterized in that: connection hole groups are provided on the circumference of the filter sheet body of the filter sheet group, and the filter sheet group is fixed between the top fixing member and the bottom closing member through the connecting shafts in the connection hole groups; filter sheet gaps are provided between adjacent two filter sheet bodies of the filter sheet group through filter spacers.

[0014] As a preferred solution of the present invention, the filter sheet body is an annular body, and the connection hole groups are provided on the inner side of the annular body; an external cleaning blade is provided outside the filter sheet group corresponding to the filter sheet gap between two filter sheet bodies; an external cleaning gasket is provided between adjacent two external cleaning blades.

[0015] As another preferred solution of the present invention, the filter sheet body is an annular body, and the connection hole groups are provided on the outer side of the annular body; an internal cleaning blade is provided inside the filter sheet group corresponding to the filter sheet gap between two filter sheet bodies; an internal cleaning gasket is provided between adjacent two internal cleaning blades.

[0016] The self-cleaning filter with sheet gaps of the present invention using the above-mentioned filter element includes a housing, and a transmission shaft is arranged inside the housing. It is characterized in that: the transmission shaft is fixedly connected to the top fixing part of the filter element through a key; the filter sheet body of the filter element is an annular body, and the connecting hole group is arranged inside the annular body; an external cleaning blade is arranged outside the filter sheet group corresponding to the filter sheet gap between two filter sheet bodies; the external cleaning blade is connected to the housing through at least two support shafts.

[0017] The self-cleaning filter with sheet gaps of the present invention using the above-mentioned filter element includes a housing, and the top fixing part of the filter element is fixedly connected to the housing; the filter sheet body is an annular body, and the connecting hole group is arranged outside the annular body; an internal cleaning blade is arranged inside the filter sheet group corresponding to the filter sheet gap between two filter sheet bodies; a transmission shaft is arranged inside the housing, and the transmission shaft is connected to a transmission part inside the housing through a key; the internal cleaning blade is connected to the transmission part through at least two support shafts.

[0018] The beneficial effects of the present invention are as follows: 1. Since the filter element of the present invention adopts a structure of a connecting hole group composed of multiple through holes arranged on the circumference of the filter sheet body, during connection, compared with the existing filter element structure with a central through shaft, the gap between the filter sheets remains stable and unchanged.

[0019] 2. Because the connecting shaft of the filter element structure of the present invention is arranged on the circumference, the gap between the filter sheets can be kept stable and unchanged. Therefore, the diameter of the filter sheet of the present invention is not limited, and it is suitable for filters with any inlet and outlet diameters, and can be used in both small-diameter filters and large-diameter filters; in addition, for the self-cleaning filter with sheet gaps of the present invention, the fixing elements of the filter element part and the fixing elements of the cleaning part are separated and fastened separately, which is different from the existing filter where the filter element part and the cleaning part share a bottom plate, and it is easy to ensure the required gap for relative rotation between the filter sheet and the cleaning blade.

[0020] 3. The transmission shaft of the present invention is connected to the top fixing part or the transmission part through a key, and the cross-section does not need to be processed into a D shape; the cleaning blade is fixed through at least two support shafts, which has a good anti-rotation effect, and the support shafts can adopt optical shafts, with a simple structure and convenient processing.

[0021] 4. Since the structure of the filter element of the present invention can be suitable for filters with any inlet and outlet diameters, the application range is expanded. The application fields include industries such as petroleum, petrochemical, chemical, metallurgy, pharmaceutical, food industry, water treatment, environmental protection, and machinery.

[0022] 5. The slit-type self-cleaning filter of the present invention is suitable for filtering liquids of various viscosities, especially in the field of solid-liquid separation applications of high-viscosity liquids such as heavy oil and polyurethane in petrochemical industry, and its advantages are more obvious. It solves the problem of difficult cleaning of the filter mesh, realizes on-line automatic cleaning without stopping the machine, improves work efficiency and reduces the labor intensity of workers. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is Figure 2 the A-A cross-sectional view of.

[0024] Figure 2 is Figure 1 the B-B cross-sectional view of.

[0025] Figure 3 is Figure 1 the structural diagram of the filter sheet in.

[0026] Figure 4 is Figure 1 the structural diagram of the filter spacer in.

[0027] Figure 5 is Figure 1 the structural diagram of the cleaning wiper in.

[0028] Figure 6 is the structural schematic diagram of a filter of the present invention, which is Figure 7 the C-C cross-sectional view of.

[0029] Figure 7 is Figure 6 the D-D cross-sectional view of.

[0030] Figure 8 is Figure 6 the structural diagram of the filter sheet body in.

[0031] Figure 9 is Figure 6 the structural diagram of the external cleaning wiper in.

[0032] Figure 10 is Figure 6 the structural diagram of the external cleaning gasket in.

[0033] Figure 11 is Figure 6 the structural diagram of the top fixing part in.

[0034] Figure 12 is the structural schematic diagram of another filter of the present invention, which is Figure 13 the G-G cross-sectional view of.

[0035] Figure 13 is Figure 12 the H-H cross-sectional view of.

[0036] Figure 14 is Figure 12 The structural diagram of the filter sheet body in

[0037] Figure 15 is Figure 12 The structural diagram of the internal cleaning wiper blade in

[0038] Figure 16 is Figure 12 The structural diagram of the internal cleaning gasket in

[0039] Figure 17 is Figure 12 Another structural diagram of the internal cleaning wiper blade that can be adopted in

[0040] Figure 18 It is the structural schematic diagram of the third filter of the present invention, which is Figure 19 The N-N sectional view of

[0041] Figure 19 is Figure 18 The K-K sectional view of

[0042] In Figures 6 to 19 of the attached drawings, 17 is the housing, 18 is the bottom closure, 19 is the wiper blade fixing ring, 20 is the filter sheet body, 21 is the filter sheet gap, 22 is the inlet, 23 is the intermediate partition, 24 is the top fixing member, 25 is the transmission shaft, 26 is the reduction motor, 27 is the outlet, 28 is the connecting shaft, 29 is the support shaft, 30 is the external cleaning gasket, 31 is the external cleaning wiper blade, 32 is the filter partition, 33 is the sewage discharge mechanism, 34 is the connecting rod, 35 is the connecting hole group, 36 is the lower cavity, 37 is the upper cavity, 38 is the transmission member, 39 is the wiper blade fixing member, 40 is the internal cleaning gasket, and 41 is the internal cleaning wiper blade. Specific embodiments

[0043] The filter element of the sheet gap type self-cleaning filter of the present invention includes a top fixing member 24, a bottom closure 18 and a filter sheet group, and is characterized in that: connection hole groups 35 are arranged on the circumference of the filter sheet body 20 of the filter sheet group, and the filter sheet group is fixed between the top fixing member 24 and the bottom closure 18 through the connecting shaft 28 in the connection hole groups 35; a filter sheet gap 21 is arranged between adjacent two filter sheet bodies 20 of the filter sheet group through a filter partition 32.

[0044] The connection hole groups 35 are at least three connection holes uniformly distributed on the circumference of the filter sheet body 20; a filter partition 32 is arranged on each connecting shaft 28 between two filter sheet bodies 20; to ensure the stability of the gap size between two filter sheet bodies 20.

[0045] The filter partition 32 can be a circular washer, which has a simple structure, is convenient for production and processing, and has a low cost.

[0046] As a preferred embodiment of the present invention, the filter sheet body 20 is an annular body, and the connection hole group 35 is arranged on the inner side of the annular body; an external cleaning blade 31 is arranged outside the filter sheet group corresponding to the filter sheet gap 21 between two filter sheet bodies 20; an external cleaning gasket 30 is arranged between two adjacent external cleaning blades 31.

[0047] As another preferred embodiment of the present invention, the filter sheet body 20 is an annular body, and the connection hole group 35 is arranged on the outer side of the annular body; an internal cleaning blade 41 is arranged inside the filter sheet group corresponding to the filter sheet gap 21 between two filter sheet bodies 20; an internal cleaning gasket 40 is arranged between two adjacent internal cleaning blades 41.

[0048] The present invention uses the slit-type self-cleaning filter with the above-mentioned filter element, which includes a housing 17. A transmission shaft 25 is arranged inside the housing 17. It is characterized in that: the transmission shaft 25 is fixedly connected with the top fixing part 24 of the filter element through a key; the filter sheet body 20 of the filter element is an annular body, and the connection hole group 35 is arranged on the inner side of the annular body; an external cleaning blade 31 is arranged outside the filter sheet group corresponding to the filter sheet gap 21 between two filter sheet bodies 20; the external cleaning blade 31 is connected with the housing 17 through at least two support shafts 29.

[0049] Example: As Figures 6 to 11 shown, an upper cavity 37 and a lower cavity 36 are formed inside the housing 17 through an intermediate partition 23. The filter element is arranged in the lower cavity 36. An inlet 22 communicating with the lower cavity 36 and an outlet 27 communicating with the upper cavity 37 are arranged on the housing 17; the lower end of the transmission shaft 25 inside the housing 17 passes through the filter element and is connected with the bottom closure 18 through a nut. The middle part of the transmission shaft 25 is connected with the top fixing part 24 through a key; the upper end of the transmission shaft 25 passes through the upper cavity 37 and is connected with a reduction motor 26 outside the housing 17; the upper end of the support shaft 29 of the external cleaning blade 31 is fixedly connected with the intermediate partition 23 of the housing 17, and the lower end of the support shaft 29 is connected with a blade fixing ring 19, and the blade fixing ring 19 is fixedly connected with the intermediate partition 23 inside the housing 17; the opening on the top fixing part 24 of the filter element communicates with the outlet 27 on the housing 17; a sewage discharge mechanism 33 communicating with the lower cavity 36 is arranged at the bottom of the housing 17.

[0050] The blade fixing ring 19 and the intermediate partition 23 inside the housing 17 are fixedly connected through a connecting rod 34.

[0051] The support shaft 29, the external cleaning blade 31 and the external cleaning gasket 30 form a cleaning assembly; multiple groups of cleaning assemblies can be arranged inside the housing 17 according to needs to improve the cleaning effect of large filters.

[0052] The liquid flow direction is as Figure 6As shown by the arrow in [description], during use, the liquid enters from the inlet 22, enters the interior of the filter element through the filter sheet gaps 21 of the filter element. The particulate matter remains in the lower chamber 36 under the filtering action of the filter element and is discharged through the sewage discharge assembly at the bottom of the housing 17. The liquid that enters the interior of the filter element flows into the upper chamber 37 from the opening above the filter element and is then discharged through the outlet 27, completing the filtration of the liquid.

[0053] When the filter element is blocked by particulate matter or impurities, causing the flow rate of the filter to decrease, it can be controlled by means of pressure detection or regular execution, etc., to rotate the transmission shaft 25. The transmission shaft 25 drives the top fixing member 24 to rotate through a key, thereby driving the entire filter element to rotate. Since the external cleaning blade 31 is fixed and located between the filter sheet gaps 21, as the filter element rotates, the external cleaning blade 31 cleans the filter sheet gaps 21.

[0054] The slit-type self-cleaning filter of the present invention using the above filter element includes a housing 17. The top fixing member 24 of the filter element is fixedly connected to the housing 17. The filter sheet body 20 is an annular body, and the connection hole group 35 is arranged on the outer side of the annular body. An internal cleaning blade 41 is arranged inside the filter sheet group corresponding to the filter sheet gap 21 between the two filter sheet bodies 20. A transmission shaft 25 is arranged in the housing 17, and the transmission shaft 25 is connected to a transmission member 38 in the housing 17 through a key. The internal cleaning blade 41 is connected to the transmission member 38 through at least two support shafts 29.

[0055] Embodiment: As Figures 12 to 17 shown, the top fixing member 24 of the filter element is arranged in the middle of the housing 17 and is matched with the inner surface of the housing 17. Above the top fixing member 24 is the upper chamber 37, and below the top fixing member 24 is the lower chamber 36. An inlet 22 communicating with the upper chamber 37 is arranged on the housing 17. In this embodiment, since the transmission member 38 has the same shape as the internal cleaning gasket 40, an opening above the filter element is formed between it and the top fixing member 24, and this opening communicates with the inlet 22. The lower end of the transmission shaft 25 in the housing 17 passes through the filter element and is connected to a blade fixing member 39 through a nut. The middle of the transmission shaft 25 is connected to the transmission member 38 through a key. The upper end of the transmission shaft 25 passes through the upper chamber 37 and is connected to a reduction motor 26 outside the housing 17. The upper end of the support shaft 29 of the internal cleaning blade 41 is connected to the transmission member 38, and the lower end of the support shaft 29 of the internal cleaning blade 41 is connected to the blade fixing member 39. The bottom closing member 18 of the filter element is matched with the inner wall of the lower chamber 36 of the housing 17. An outlet 27 is arranged on the housing 17 corresponding to the position between the top fixing member 24 and the bottom closing member 18. Since the blade fixing member 39 also has the same shape as the internal cleaning gasket 40, an opening below the filter element is formed between it and the bottom closing member 18, and a sewage discharge mechanism 33 communicating with the lower chamber 36 is arranged at the bottom of the housing 17.

[0056] The internal cleaning blade 41 can be set in the shape of a straight line, a cross, a star, etc., and can be freely set according to the filter element size and working conditions.

[0057] The liquid flow direction is as Figure 12 shown by the arrow in the figure. When in use, the liquid enters from the inlet 22, then enters the interior of the filter element through the upper opening of the filter element, flows through the filter gap 21 to the outside of the filter element. After the filter gap 21 blocks the particulate matter, the particulate matter enters the sewage discharge assembly through the lower opening of the filter element and is discharged. The liquid filtered by the filter element then flows out through the outlet 27.

[0058] When the filter element is blocked by particulate matter or impurities, causing the flow rate of the filter to decrease, it can be controlled by means of pressure detection or regular execution, etc., to rotate the transmission shaft 25. The transmission shaft 25 drives the transmission part 38 to rotate through a key, thereby driving the internal cleaning blade 41 to rotate. The internal cleaning blade 41 is located in the filter gap 21, while the filter element remains stationary. Under the relative movement, the internal cleaning blade 41 removes the particulate matter in the filter gap 21.

[0059] Embodiment: As Figure 18 , 19 shown, the top fixing part 24 of the filter element is arranged in the middle of the housing 17 and is matched with the inner surface of the housing 17. Above the top fixing part 24 is the upper cavity 37, and below the top fixing part 24 is the lower cavity 36. The housing 17 is provided with an outlet 27 communicating with the upper cavity 37 and an inlet 22 communicating with the lower cavity 36. In this embodiment, since the transmission part 38 has the same shape as the internal cleaning gasket 40, an opening above the filter element is formed between it and the top fixing part 24, and this opening communicates with the outlet 27; the lower end of the transmission shaft 25 in the housing 17 passes through the filter element and is connected to a blade fixing part 39 through a nut. The middle of the transmission shaft 25 is connected to the transmission part 38 through a key; the upper end of the transmission shaft 25 passes through the upper cavity 37 and is connected to a reduction motor 26 outside the housing 17; the upper end of the support shaft 29 of the internal cleaning blade 41 is connected to the transmission part 38, and the lower end of the support shaft 29 of the internal cleaning blade 41 is connected to the blade fixing part 39; a sewage discharge mechanism 33 communicating with the lower cavity 36 is arranged at the bottom of the housing 17.

[0060] The internal cleaning blade 41 can be set in the shape of a straight line, a cross, a star, etc., and can be freely set according to the filter element size and working conditions.

[0061] The liquid flow direction is as Figure 18 shown by the arrow in the figure. When in use, the liquid enters from the inlet 22, then flows through the filter gap 21 to the inside of the filter element. After the filter gap 21 blocks the particulate matter, the particulate matter directly enters the sewage discharge assembly and is discharged. The liquid filtered by the filter element enters the upper cavity 37 through the upper opening of the filter element and then flows out through the outlet 27.

[0062] When the filter element is blocked by particulate matter or impurities, causing the flow rate of the filter to decrease, the rotation of the transmission shaft 25 can be controlled by means of pressure detection or regular execution. The transmission shaft 25 drives the transmission part 38 to rotate through a key, thereby driving the internal cleaning blade 41 to rotate. The internal cleaning blade 41 is located within the filter element gap 21, while the filter element remains stationary. Under relative movement, the internal cleaning blade 41 removes the particulate matter within the filter element gap 21.

[0063] It can be understood that the above specific description of the present invention is only for explaining the present invention and is not limited to the technical solutions described in the embodiments of the present invention. Those of ordinary skill in the art should understand that the present invention can still be modified or equivalently replaced to achieve the same technical effect; as long as it meets the usage requirements, it is within the protection scope of the present invention.

Claims

1. A slit-type self-cleaning filter, comprising a filter element and a housing (17), wherein the filter element includes a top fixing member (24), a bottom closing member (18) and a filter sheet group, and is characterized in that: The circumferences of the filter sheets (20) of the filter sheet group are provided with connection hole groups (35), and the filter sheet group is fixed between the top fixing member (24) and the bottom closing member (18) through the connecting shafts (28) in the connection hole groups (35); a filter sheet gap (21) is provided between two adjacent filter sheets (20) of the filter sheet group through a filter spacer (32); The connection hole groups (35) are at least three connection holes evenly distributed on the circumference of the filter sheet body (20); a filter spacer (32) is arranged on each connecting shaft (28) between two filter sheets (20); the filter sheet body (20) is an annular body, and the connection hole groups (35) are arranged on the inner side of the annular body; an external cleaning blade (31) is arranged outside the filter sheet group corresponding to the filter sheet gap (21) between two filter sheets (20); an external cleaning gasket (30) is arranged between two adjacent external cleaning blades (31); A transmission shaft (25) is arranged in the housing (17). The middle part of the transmission shaft (25) is connected to the top fixing member (24) through a key. The lower end of the transmission shaft (25) passes through the filter element and is connected to the bottom closing member (18) through a nut; the external cleaning blade (31) is connected to the housing (17) through at least two support shafts (29); The upper end of the support shaft (29) of the external cleaning blade (31) is fixedly connected to the middle partition plate (23) of the housing (17), and the lower end of the support shaft (29) is connected to a blade fixing ring (19), and the blade fixing ring (19) is fixedly connected to the middle partition plate (23) in the housing (17).

2. The slit-type self-cleaning filter according to claim 1, characterized in that: The housing (17) forms an upper chamber (37) and a lower chamber (36) through the middle partition plate (23). The filter element is arranged in the lower chamber (36). The housing (17) is provided with an inlet (22) communicating with the lower chamber (36) and an outlet (27) communicating with the upper chamber (37); the upper end of the transmission shaft (25) passes through the upper chamber (37) and is connected to a reduction motor (26) outside the housing (17); the opening on the top fixing member (24) of the filter element communicates with the outlet (27) on the housing (17); a sewage discharge mechanism (33) communicating with the lower chamber (36) is arranged at the bottom of the housing (17).

3. The slit-type self-cleaning filter according to claim 2, characterized in that: The support shafts (29), the external cleaning blades (31) and the external cleaning gaskets (30) constitute a cleaning assembly; more than one group of cleaning assemblies are arranged in the housing (17).

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