Inverted pre-filter

Abstract

The invention relates to an inverted pre-filter which comprises a valve casing, a filtering and backwashing mechanism and a filter bottle, the valve casing is provided with a water inlet end, a water outlet end, an upward filter bottle assembling end and a valve casing cavity, the filter bottle and the filter bottle assembling end are fixed in a matched mode, the filtering and backwashing mechanism is arranged in the filter bottle, and a cavity between the filtering mechanism and the filter bottle forms a raw water cavity. The filtering and backwashing mechanism comprises a filtering mechanism and a backwashing mechanism which are coaxially arranged, a flow guide seat is arranged in the valve shell cavity and divides the valve shell cavity into a water inlet end valve shell cavity, a central end valve shell cavity and a water outlet end valve shell cavity, the water inlet end valve shell cavity is communicated with the water inlet end and is provided with a particle pollution discharge control valve, and the central end valve shell cavity is communicated with the water outlet end. The central end valve shell cavity is communicated with a filter screen backwashing blow-down valve through a central blow-down pipe, and the water outlet end valve shell cavity is communicated with the water outlet end. The structure is more optimized, installation occasions can be easily matched, and the multiple drainage channels are arranged so that different application modes can be met.

Description

Technical Field

[0001] The invention relates to an inverted pre-filter and belongs to the technical field of water purification equipment. Background Art

[0002] The mainstream pre-filter products in the prior art are of the filter bottle bottom type, including: a machine head, a filter bottle connected to the machine head at the upper end, and a drainage ball valve connected to the lower end of the filter bottle. A filter element skeleton is arranged in the filter bottle, and the outer wall of the filter element skeleton is provided with a filter element. During use, water flows from the water inlet of the machine head into the gap between the filter bottle and the filter element, flows into the center of the filter element skeleton after being filtered by the filter element, and then flows from the center of the filter element skeleton to the water outlet of the machine head. When sewage needs to be discharged, the drainage ball valve at the lower end of the filter bottle is opened to achieve it.

[0003] In some installation occasions, the installation of the pre-filter with the filter bottle below is inconvenient. Therefore, an inverted pre-filter is born to meet market demand. The valve head of this pre-filter, in addition to the water inlet, water outlet and filter bottle installation port, also needs to be equipped with a sewage outlet, that is, the function of the drainage ball valve originally set at the lower end of the filter bottle needs to be transferred to the valve head, so the traditional valve head structure needs to be optimized and adjusted.

[0004] In addition, during the use of the pre-filter, the filter element needs to be cleaned regularly, which is generally achieved by a back-flushing mechanism and then discharged through the sewage outlet. However, the back-flushing filter of the back-flushing mechanism itself also needs to solve the problem of regular flushing and sewage discharge. The present invention aims to provide an inverted pre-filter with a more optimized structure, easy to match the installation occasion, and multiple sewage discharge channels to meet different application modes. Summary of the invention

[0005] One of the purposes of the present invention is to solve the deficiencies of the prior art pre-filter and to provide an inverted pre-filter with a more optimized structure, easy to match the installation occasion, and having multiple sewage discharge channels to meet different application modes.

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

[0007] An inverted pre-filter comprises a valve housing, a filtering and backwashing mechanism and a filter bottle, wherein the valve housing is provided with an inlet end, an outlet end, an upward filter bottle assembly end and a valve housing cavity, the filter bottle is fixed with the filter bottle assembly end, the filtering and backwashing mechanism is arranged in the filter bottle, the cavity between the filtering mechanism and the filter bottle constitutes a raw water cavity, the filtering and backwashing mechanism comprises a coaxially arranged filtering mechanism and a backwashing mechanism, a guide seat is arranged in the valve housing cavity, the guide seat divides the valve housing cavity into an inlet end valve housing cavity, a central end valve housing cavity and an outlet end valve housing cavity, the inlet end valve housing cavity is connected with the inlet end and is provided with a particle drainage channel, the central end valve housing cavity is connected with a filter element backwashing drainage channel through a central drainage pipe, and the outlet end valve housing cavity is connected with the outlet end; the end of the backwashing mechanism is adapted to the central end valve housing cavity, and the backwashing mechanism can move axially relative to the filtering mechanism under the action of the pressure difference to switch the filtering mode and the backwashing mode.

[0008] The present invention realizes setting the water inlet end, the water outlet end, and the upward filter bottle assembly end on the valve head, and also sets two independent sewage valve particle sewage discharge channels and the filter element backwash sewage discharge channel, that is, the function of the drainage ball valve originally set at the lower end of the filter bottle is transferred to the valve head, and the traditional valve head structure is effectively optimized and adjusted. During filtration, the raw water flows into the raw water cavity between the filter mechanism and the filter bottle from the water inlet end and the water inlet end valve shell cavity in sequence, and after filtration, it flows out through the central end valve shell cavity, the water outlet end valve shell cavity and the water outlet end; large particle impurities accumulate in the water inlet end valve shell cavity, and can be directly discharged through the particle sewage discharge channel. In the backwash mode, the sewage backwashed on the filter element enters the raw water cavity, and the raw water cavity is retained in the filter element backwash sewage discharge channel through the central sewage pipe for discharge. The structure is more optimized, easy to match the installation occasion, and has multiple sewage discharge channels to meet different application modes.

[0009] Preferably, the filtering mechanism comprises a filtering skeleton and a filtering element, the filtering skeleton comprises a skeleton body, an inlet end cover and a skeleton bottom cover, the inlet end cover is provided with a raw water inlet channel and a backwashing skeleton assembly port, the skeleton bottom cover is provided with a backwashing skeleton assembly port; the backwashing mechanism comprises a backwashing skeleton and a backwashing filtering element, the backwashing skeleton is divided into a backwashing section, an assembly section and a driving section, the assembly section is inserted into the skeleton body, the backwashing section and the driving section extend from the backwashing skeleton assembly port, the backwashing filtering element is fixed to the backwashing section, the backwashing section is located in the central end valve shell cavity, and is slidingly sealed and connected to the central end valve shell cavity, the backwashing section is also provided with a sealing The backwash mechanism comprises a sealing part, wherein the sealing part can close or open the raw water inlet channel when the backwash mechanism moves axially; the driving section is fixedly provided with a backwash cover, and the backwash cover is provided with a backwash water hole; the driving section also comprises an elastic reset member, and the elastic reset member is provided between the skeleton body and the backwash skeleton, or between the backwash cover and the inner wall of the filter bottle, and under the action of the pressure difference on both sides of the backwash cover, the backwash mechanism is driven to move axially relative to the filtering mechanism; the backwash mechanism moves upward to close the raw water inlet channel, and the backwash section is exposed from the central end valve shell cavity to enter the backwash mode; the driving section moves downward to open the raw water inlet channel, and the backwash section extends into the central end valve shell cavity to enter the filtering mode.

[0010] Preferably, there is a pressure difference △P on both sides of the backwash cover, △P ≥ 0, when the action force corresponding to △P is greater than the reaction force of the elastic reset member, the elastic reset member is stretched or compressed, and the backwash mechanism moves axially upward in the direction opposite to the sewage flow; when the action force corresponding to △P is less than the reaction force of the elastic reset member, the elastic reset member is reset, and the backwash mechanism moves axially downward in the direction of the sewage flow; the size of the pressure difference △P is adjusted by opening and closing the backwash sewage discharge channel of the filter element.

[0011] Preferably, the outlet valve housing cavity is further provided with a backwash filter cavity, the backwash filter cavity is provided with a backwash filter element flushing drainage channel, and the central valve housing cavity is provided with a backwash filter element flushing channel. In the backwash mode of the backwash filter, the sewage backwashed on the backwash filter enters the outlet valve housing cavity, and is discharged through the backwash filter element flushing drainage channel, thereby expanding multiple drainage channels to meet different application modes.

[0012] Preferably, the filter bottle assembly end is provided with a quick-install structure assembled with the filter bottle, and the quick-install structure adopts a detachable structure, including a screw connection structure and a clamping structure. This quick-install structure is convenient for users to install, and is also convenient for replacement and maintenance of the filter bottle, or when the valve head is blocked by impurities, it is easy to disassemble and clean.

[0013] Preferably, the filter skeleton is a filter mesh skeleton, and the filter element is a filter mesh or PP cotton; the backwash skeleton is a backwash filter mesh skeleton, and the backwash filter element is a filter mesh or PP cotton; or, the filter skeleton and the backwash skeleton are both laminated skeletons, and the filter element and the backwash filter element are both filter laminates.

[0014] Preferably, the guide seat is provided with a buffer wall in the valve housing cavity at the water inlet end, and a buffer zone is formed under the buffer wall. By setting the buffer wall and the buffer zone, large particle impurities are deposited when passing through and discharged through the particle drainage channel, delaying the clogging of the filter element and improving the performance of the pre-filter.

[0015] Preferably, the buffer wall includes a blocking portion, an oblique flow guide portion and a vertical flow guide portion, and the junction of the blocking portion, the oblique flow guide portion and the vertical flow guide portion is in an arc transition. By changing the direction and velocity of the water flow, the effect of large particle impurity deposition is improved, the performance of the pre-filter is further improved, and its service life is extended.

[0016] Preferably, the guide seat is provided with a guide pipe in the valve shell cavity at the water outlet end, and the guide pipe is provided with a transition zone. Through the arrangement of the guide pipe and the transition zone, the purified water at the water outlet end can flow out stably, avoiding large flow rate and flow velocity fluctuations.

[0017] Preferably, the transition zone is in the form of an arc transition, and the axial direction of the flow guide tube is consistent with the axial direction of the water outlet. The setting of the arc transition zone and the axial direction being consistent can reduce the resistance of the purified water outflow, allowing the purified water at the water outlet to flow out stably and avoiding large flow and flow rate fluctuations.

[0018] Preferably, the guide seat is integrally formed of an inert material, the inert material is rubber or plastic, or at least one side in contact with water is provided with an inert material coating, the inert material is plastic, rubber or ceramic.

[0019] Preferably, the guide seat is provided with an assembly part in the central end valve shell cavity, and the assembly part is adapted to the backwash section of the backwash filtration mechanism of the inverted pre-filter, and the inner cavity of the filtration and backwash mechanism can be connected to the central end valve shell cavity.

[0020] Preferably, the water inlet end, the water outlet end and the filter bottle assembly end are provided with isolation bushings, and the isolation bushings are made of inert materials. The isolation bushings include an isolation bushing at the water inlet end, an isolation bushing at the water outlet end and an isolation bushing at the assembly end, which are integrally injection molded using plastic or rubber materials; or at least one side of the isolation bushing in contact with water is provided with an inert material coating, and the inert material is plastic, rubber or ceramic.

[0021] The beneficial effects of the present invention are as follows: the present invention realizes setting the water inlet end, the water outlet end, and the upward filter bottle assembly end on the valve head, and also sets two independent sewage valve particle sewage discharge channels and the filter element backwash sewage discharge channel, that is, the function of the drainage ball valve originally set at the lower end of the filter bottle is to be transferred to the valve head, and the traditional valve head structure is effectively optimized and adjusted. During filtration, the raw water flows into the raw water cavity between the filter mechanism and the filter bottle from the water inlet end and the water inlet end valve shell cavity in sequence, and after filtration, it flows out through the central end valve shell cavity, the water outlet end valve shell cavity and the water outlet end; large particle impurities accumulate in the water inlet end valve shell cavity, and can be directly discharged through the particle sewage discharge channel. In the backwash mode, the sewage backwashed on the filter element enters the raw water cavity, and the raw water cavity is retained in the filter element backwash sewage discharge channel through the central sewage pipe for discharge. The structure is more optimized, easy to match the installation occasion, and has multiple sewage discharge channels to meet different application modes. In the backwash mode of the backwash filter, the sewage that is backwashed on the backwash filter enters the valve shell cavity at the outlet end, is flushed through the backwash filter element and discharged through the sewage discharge channel, thus expanding multiple sewage discharge channels to meet different application modes. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1 It is a schematic diagram of the structure of the present invention;

[0024] Figure 2 It is a schematic diagram of the structure of the present invention;

[0025] Figure 3 is a cross-sectional view of the present invention (filtering state);

[0026] Figure 4 is a cross-sectional view of the present invention (particles arranged in a straight line);

[0027] Figure 5 is a cross-sectional view of the present invention (backwashing filter element flushing and sewage discharge);

[0028] Figure 6 It is a cross-sectional view of the present invention for direct particle discharge (backwashing and drainage of filter elements);

[0029] Figure 7 is an exploded view of the present invention;

[0030] Figure 8 yes Figure 7 A partial exploded view of the .

[0031] In the figure: 1. valve housing, 11. water inlet end, 12. water outlet end, 13. filter bottle assembly end, 14. valve housing cavity, 14a. water inlet end valve housing cavity, 14b. central end valve housing cavity, 14c. water outlet end valve housing cavity, 14d. backwashing filtration cavity, 2. guide seat, 21. buffer wall, 22. buffer zone, 23. guide pipe, 24. transition zone, 3. particle drainage channel, 4. central drainage pipe, 5. filter element backwashing drainage channel, 6. backwashing filter element flushing drainage channel, 7. filter bottle, 8. filter skeleton, 81. water inlet end cover, 82. skeleton bottom cover, 9. filter element, 10. backwashing skeleton, 10a. backwashing filter element, 10b. backwashing cover, 10c. sealing part, A. elastic reset part. DETAILED DESCRIPTION

[0032] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and are not to be construed as limitations of the present invention.

[0033] In the description of the present invention, it should be understood that descriptions involving orientations, such as up, down, front, back, left, right, etc., and orientations or positional relationships indicated are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0034] In the description of the present invention, if there is a description of first and second, it is only for the purpose of distinguishing the technical features, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0035] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0036] Example 1

[0037] like Figure 1-8As shown, the inverted pre-filter comprises a valve housing 1, a filtering and backwashing mechanism and a filter bottle 7, wherein the valve housing 1 is provided with a water inlet end 11, a water outlet end 12, an upward filter bottle assembly end 13 and a valve housing cavity 14, the filter bottle 7 is fixedly matched with the filter bottle assembly end 13, the filtering and backwashing mechanism is arranged in the filter bottle 7, and the cavity between the filtering mechanism and the filter bottle 7 constitutes a raw water cavity, the filtering and backwashing mechanism comprises a coaxially arranged filtering mechanism and a backwashing mechanism, and is characterized in that: a guide seat 2 is arranged in the valve housing cavity 14, and the guide seat 2 divides the valve housing cavity 14 into It is divided into a water inlet valve shell chamber 14a, a central valve shell chamber 14b and a water outlet valve shell chamber 14c. The water inlet valve shell chamber 14a is connected to the water inlet end 11 and is provided with a particle discharge passage 3. The central valve shell chamber 14b is connected to the filter element backwash discharge passage 5 through a central discharge pipe 4. The water outlet valve shell chamber 14c is connected to the water outlet end 12. The end of the backwash mechanism is adapted to the central valve shell chamber 14b. The backwash mechanism can move axially relative to the filter mechanism under the action of the pressure difference to switch the filter mode and the backwash mode.

[0038] The present invention realizes setting the water inlet end, the water outlet end, and the upward filter bottle assembly end on the valve head, and also sets two independent sewage valve particle sewage discharge channels and the filter element backwash sewage discharge channel, that is, the function of the drainage ball valve originally set at the lower end of the filter bottle is transferred to the valve head, and the traditional valve head structure is effectively optimized and adjusted. During filtration, the raw water flows into the raw water cavity between the filter mechanism and the filter bottle from the water inlet end and the water inlet end valve shell cavity in sequence, and after filtration, it flows out through the central end valve shell cavity, the water outlet end valve shell cavity and the water outlet end; large particle impurities accumulate in the water inlet end valve shell cavity, and can be directly discharged through the particle sewage discharge channel. In the backwash mode, the sewage backwashed on the filter element enters the raw water cavity, and the raw water cavity is retained in the filter element backwash sewage discharge channel through the central sewage pipe for discharge. The structure is more optimized, easy to match the installation occasion, and has multiple sewage discharge channels to meet different application modes.

[0039] Specifically, the filtering mechanism includes a filtering skeleton 8 and a filtering element 9. The filtering skeleton 8 includes a skeleton body, an inlet end cover 81 and a skeleton bottom cover 82. The inlet end cover 81 is provided with a raw water inlet channel and a backwashing skeleton assembly port, and the skeleton bottom cover 82 is provided with a backwashing skeleton assembly port; the backwashing mechanism includes a backwashing skeleton 10 and a backwashing filtering element 10a. The backwashing skeleton 10 is divided into a backwashing section, an assembly section and a driving section. The assembly section is inserted into the skeleton body, and the backwashing section and the driving section extend from the backwashing skeleton assembly port. The backwashing filtering element 10a is fixed to the backwashing section. The backwashing section is located in the central end valve shell cavity 14b and is slidably sealed with the central end valve shell cavity 14b. The backwashing section is also provided with a sealing The backwash mechanism comprises a sealing portion 10c, and the sealing portion 10c can close or open the raw water inlet channel when the backwash mechanism moves axially; the driving section is fixedly provided with a backwash cover 10b, and the backwash cover 10b is provided with a backwash water hole; it also includes an elastic reset member A, and the elastic reset member A is arranged between the skeleton body and the backwash skeleton, or between the backwash cover 10b and the inner wall of the filter bottle 7. Under the action of the pressure difference on both sides of the backwash cover 10b, the backwash mechanism is driven to move axially relative to the filtering mechanism; it moves upward to close the raw water inlet channel, and the backwash section is exposed from the central end valve shell cavity 14b to enter the backwash mode; it moves downward to open the raw water inlet channel, and the backwash section extends into the central end valve shell cavity 14b to enter the filtering mode.

[0040] In this embodiment, there is a pressure difference △P on both sides of the backwash cover 10b, △P≥0, when the action force corresponding to △P is greater than the reaction force of the elastic reset member, the elastic reset member A is stretched or compressed, and the backwash mechanism moves axially upward in the direction opposite to the sewage flow; when the action force corresponding to △P is less than the reaction force of the elastic reset member A, the elastic reset member A is reset, and the backwash mechanism moves axially downward in the direction of the sewage flow; the size of the pressure difference △P is adjusted by opening and closing the backwash sewage channel 5 of the filter element.

[0041] In this embodiment, the outlet valve shell cavity 14c is also provided with a backwash filter cavity 14d, and the backwash filter cavity 14d is provided with a backwash filter element flushing sewage channel 6, and the central valve shell cavity 14b is provided with a backwash filter element flushing channel; in the backwash mode of the backwash filter, the sewage that is backwashed on the backwash filter enters the outlet valve shell cavity, and is discharged through the backwash filter element flushing sewage channel 6, thereby expanding multiple sewage channels to meet different application modes. The filter bottle assembly end 13 is provided with a quick-install structure assembled with the filter bottle, and the quick-install structure adopts a detachable structure, including a screw structure and a clamping structure. This quick-install structure is convenient for users to install, and is also convenient for replacement and maintenance of the filter bottle, or when the valve head is clogged by residual impurities, it is easy to disassemble and clean.

[0042] In this embodiment, the filter frame is a filter frame, and the filter element is a filter or PP cotton; the backwash frame is a backwash filter frame, and the backwash filter element is a filter or PP cotton; or, the filter frame and the backwash frame are both laminated frames, and the filter element and the backwash filter element are both filter laminates. More specifically, the guide seat 2 is provided with a buffer wall 21 in the valve shell cavity 14a at the water inlet end, and a buffer zone 22 is formed under the buffer wall 21. Through the setting of the buffer wall and the buffer zone, large particle impurities are allowed to settle when passing through, and are discharged through the particle drainage channel 3, delaying the clogging of the filter element and improving the performance of the pre-filter. The buffer wall 21 includes a blocking part, an oblique flow guide part and a vertical flow guide part, and the junction of the blocking part, the oblique flow guide part and the vertical flow guide part is in an arc transition. Through the change of water flow direction and flow velocity, the effect of large particle impurity deposition is improved, the performance of the pre-filter is further improved, and its service life is extended. The guide seat 2 is provided with a guide pipe 23 in the valve shell cavity 14c at the water outlet end, and the guide pipe 23 is provided with a transition zone 24. Through the setting of the guide pipe and the transition zone, the purified water at the outlet can flow out stably, avoiding large flow rate and flow velocity fluctuations.

[0043] In this embodiment, the transition zone 24 is an arc transition, and the axial direction of the flow guide tube 23 is consistent with the axial direction of the water outlet 12. The setting of the arc transition zone and the axial direction being consistent can reduce the resistance of the purified water outflow, allowing the purified water at the water outlet to flow out stably and avoiding large flow rate and flow velocity fluctuations.

[0044] In this embodiment, in order to improve the environmental friendliness of the valve head, the guide seat is integrally formed of an inert material, the inert material is rubber or plastic, or at least one side in contact with water is provided with an inert material coating, the inert material is plastic, rubber or ceramic.

[0045] Specifically, the guide seat 2 is provided with an assembly part in the central end valve shell cavity 14b, and the assembly part is adapted to the backwash section of the backwash filtration mechanism of the inverted pre-filter, and the inner cavity of the filtration and backwashing mechanism can be connected with the central end valve shell cavity 14b. The water inlet end 11, the water outlet end 12 and the filter bottle assembly end 13 are provided with isolation bushings, which are made of inert materials. The isolation bushings include the water inlet end isolation bushing, the water outlet end isolation bushing and the assembly end isolation bushing, which are integrally injection molded with plastic or rubber materials; or the isolation bushing is provided with an inert material coating on at least one side in contact with water, and the inert material is plastic, rubber or ceramic.

[0046] The present invention realizes setting the water inlet end, the water outlet end, and the upward filter bottle assembly end on the valve head, and also sets two independent sewage valve particle sewage discharge channels and the filter element backwash sewage discharge channel, that is, the function of the drainage ball valve originally set at the lower end of the filter bottle is transferred to the valve head, and the traditional valve head structure is effectively optimized and adjusted. During filtration, the raw water flows into the raw water cavity between the filter mechanism and the filter bottle from the water inlet end and the water inlet end valve shell cavity in sequence, and after filtration, it flows out through the central end valve shell cavity, the water outlet end valve shell cavity and the water outlet end; large particle impurities accumulate in the water inlet end valve shell cavity, and can be directly discharged through the particle sewage discharge channel. In the backwash mode, the sewage backwashed on the filter element enters the raw water cavity, and the raw water cavity is retained in the filter element backwash sewage discharge channel through the central sewage pipe for discharge. The structure is more optimized, easy to match the installation occasion, and has multiple sewage discharge channels to meet different application modes. In the backwash mode of the backwash filter, the sewage that is backwashed on the backwash filter enters the valve shell cavity at the outlet end, is flushed through the backwash filter element and discharged through the sewage discharge channel, thus expanding multiple sewage discharge channels to meet different application modes.

[0047] 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. An inverted pre-filter, comprising a valve housing (1), a filtering and backwashing mechanism and a filter bottle (7), wherein the valve housing (1) is provided with a water inlet end (11), a water outlet end (12), an upwardly directed filter bottle assembly end (13) and a valve housing cavity (14), the filter bottle (7) and the filter bottle assembly end (13) are fixed in cooperation, the filtering and backwashing mechanism is arranged in the filter bottle (7), the cavity between the filtering mechanism and the filter bottle (7) constitutes a raw water cavity, the filtering and backwashing mechanism comprises a coaxially arranged filtering mechanism and a backwashing mechanism, and is characterized in that: A flow guide seat (2) is provided in the valve housing cavity (14), and the flow guide seat (2) divides the valve housing cavity (14) into a water inlet end valve housing cavity (14a), a central end valve housing cavity (14b) and a water outlet end valve housing cavity (14c); the water inlet end valve housing cavity (14a) is connected to the water inlet end (11) and is provided with a particle discharge passage (3); the central end valve housing cavity (14b) is connected to a filter element (9) backwash discharge passage (5) through a central discharge pipe (4); and the water outlet end valve housing cavity (14c) is connected to the water outlet end (12); the end of the backwash mechanism is adapted to the central end valve housing cavity (14b); the backwash mechanism can move axially relative to the filter mechanism under the action of a pressure difference to switch between a filter mode and a backwash mode.

2. The inverted pre-filter according to claim 1, characterized in that: The filtering mechanism comprises a filtering frame (8) and a filtering element (9), wherein the filtering frame (8) comprises a frame body, a water inlet end cover (81) and a frame bottom cover (82), wherein the water inlet end cover (81) is provided with a raw water inlet channel and a backwash frame assembly port, and the frame bottom cover (82) is provided with a backwash frame assembly port; the backwashing mechanism comprises a backwashing frame (10) and a backwashing filtering element (10a), wherein the backwashing frame (10) is provided with a backwashing section, an assembly section and a driving section, wherein the assembly section is inserted into the frame body, the backwashing section and the driving section extend from the backwashing frame assembly port, the backwashing filtering element (10a) is fixed to the backwashing section, the backwashing section is located in the central end valve shell cavity (14b), and is slidably sealed with the central end valve shell cavity (14b), and the backwashing section is also provided with a sealing The backwash mechanism is provided with a backwash cover (10b) fixedly disposed on the driving section, and the backwash cover (10b) is provided with a backwash water hole; and further comprises an elastic reset member (A), the elastic reset member (A) being disposed between the skeleton body and the backwash skeleton (10), or between the backwash cover (10b) and the inner wall of the filter bottle, and under the action of the pressure difference on both sides of the backwash cover (10b), the backwash mechanism is driven to move axially relative to the filtering mechanism; the backwash mechanism moves upward to close the raw water inlet channel, and the backwash section is exposed from the central end valve shell cavity (14b), and enters the backwash mode; the backwash mechanism moves downward to open the raw water inlet channel, and the backwash section extends into the central end valve shell cavity (14b), and enters the filtering mode.

3. The inverted pre-filter according to claim 2, characterized in that: There is a pressure difference △P on both sides of the backwash cover (10b), △P≥0, when the action force corresponding to △P is greater than the reaction force of the elastic reset member (A), the elastic reset member (A) is stretched or compressed, and the backwash mechanism moves axially upward in the direction opposite to the sewage flow; when the action force corresponding to △P is less than the reaction force of the elastic reset member (A), the elastic reset member (A) is reset, and the backwash mechanism moves axially downward in the direction of the sewage flow; the size of the pressure difference △P is adjusted by opening and closing the backwash sewage channel (5) of the filter element (9).

4. The inverted pre-filter according to claim 2 or 3, characterized in that: The outlet valve shell cavity (14c) is also provided with a backwash filter cavity (14d), the backwash filter cavity (14d) is provided with a backwash filter element flushing sewage discharge channel (6), and the central valve shell cavity (14b) is provided with a backwash filter element flushing channel; the filter bottle assembly end (13) is provided with a quick-install structure assembled with the filter bottle, and the quick-install structure adopts a detachable structure, including a screw connection structure and a clamping structure.

5. The inverted pre-filter according to claim 4, characterized in that: The filter skeleton (8) is a filter mesh skeleton, and the filter element (9) is a filter mesh or PP cotton; the backwash skeleton (10) is a backwash filter mesh skeleton, and the backwash filter element (10a) is a filter mesh or PP cotton; or, the filter skeleton (8) and the backwash skeleton (10) are both laminated skeletons, and the filter element (9) and the backwash filter element (10a) are both filter laminates.

6. The inverted pre-filter according to claim 1, 2 or 3, characterized in that: The guide seat (2) is provided with a buffer wall (21) at the water inlet end valve housing cavity (14a), and a buffer zone (22) is formed under the buffer wall (21).

7. The inverted pre-filter according to claim 6, characterized in that: The buffer wall (21) comprises a blocking portion, an oblique flow guide portion and a vertical flow guide portion, and the junction of the blocking portion, the oblique flow guide portion and the vertical flow guide portion is in an arc transition.

8. The inverted pre-filter according to claim 7, characterized in that: The flow guide seat (2) is provided with a flow guide pipe (23) in the valve shell cavity (14c) at the water outlet end, and the flow guide pipe (23) is provided with a transition zone (24); the transition zone (24) is in the form of an arc transition, and the axial direction of the flow guide pipe (23) is consistent with the axial direction of the water outlet end (12).

9. The inverted pre-filter according to claim 1, 2 or 3, characterized in that: The guide seat is integrally formed of an inert material, the inert material is rubber or plastic, or at least one side in contact with water is provided with an inert material coating, the inert material is plastic, rubber or ceramic; the water inlet end (11), the water outlet end (12) and the filter bottle assembly end (13) are provided with isolation bushings, the isolation bushings are processed from inert materials, the isolation bushings include water inlet end isolation bushings, water outlet end isolation bushings and assembly end isolation bushings, which are integrally injection molded from plastic or rubber materials; or at least one side in contact with water is provided with an inert material coating, the inert material is plastic, rubber or ceramic.

10. The inverted pre-filter according to claim 1, 2 or 3, characterized in that: The guide seat (2) is located in the central end valve shell cavity (14b) and is provided with an assembly portion, the assembly portion is adapted to the backwash section of the backwash filtering mechanism of the inverted pre-filter, and the inner cavity of the filtering and backwashing mechanism is communicable with the central end valve shell cavity (14b).

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