CN216878102U

CN216878102U - Automatic liquid filter of self-cleaning and intermittent type nature blowdown

Info

Publication number: CN216878102U
Application number: CN202123355223.4U
Authority: CN
Inventors: 黎敦林; 张松坡
Original assignee: Suzhou Daichuang Filtration System Co ltd
Current assignee: Suzhou Daichuang Filtration System Co ltd
Priority date: 2021-12-28
Filing date: 2021-12-28
Publication date: 2022-07-05
Anticipated expiration: 2031-12-28

Abstract

The utility model discloses a self-cleaning and intermittent blowdown automatic liquid filter, which comprises a cylinder body, a first filter element, a second filter element and a filter element, wherein the cylinder body comprises a first blowdown port, a second blowdown port, a first positioning disc and a second positioning disc, and the first positioning disc and the second positioning disc are arranged in the cylinder body; the driving assembly comprises a motor unit and a main shaft connected with the motor unit, and one end of the main shaft, which is far away from the motor unit, penetrates through the first positioning disc and is inserted into the filter piece; the cleaning assembly comprises a spring piece arranged at one end of the main shaft inserted into the filter piece, a cleaning piece connected with the spring piece and a cleaning piece arranged at one end of the main shaft far away from the cleaning piece; and the blowdown assembly comprises a blowdown pipeline arranged at one end of the main shaft close to the second positioning plate and a blowdown guide pipe connected with the blowdown pipeline, and the blowdown guide pipe is communicated with a blowdown port. The utility model can self-clean the filtering piece and intermittently and automatically discharge sewage, and improves the sewage filtering efficiency.

Description

Automatic liquid filter of self-cleaning and intermittent type nature blowdown

Technical Field

The utility model relates to the technical field of liquid filters, in particular to an automatic liquid filter capable of self-cleaning and intermittent pollution discharge.

Background

In the current industrial production field, a large amount of industrial sewage containing micro suspended solids is discharged from various industrial production lines, and the micro suspended solids in the industrial sewage must be filtered by a high-efficiency liquid filter, so that the industrial sewage can be recycled or discharged after reaching the standard, and the national environmental protection technical standard is met; the filters used to perform the above-mentioned industrial wastewater filtration treatment are mainly classified into two categories: first type) bag-type liquid filters that require frequent manual replacement of the filter bag; second) automatic liquid filters with self-cleaning and automatic blowdown capabilities.

The filters for filtering and treating industrial sewage, which are classified into two categories, mainly have the following technical defects:

the first type is: although the bag type liquid filter for manually replacing the filter bag has a simple structure and low manufacturing cost, because the filter bag must be frequently stopped and disassembled for inspection, a large amount of maintenance labor cost and filter bag consumable material cost are inevitably consumed for frequently manually replacing the filter bag, and in addition, huge interference is caused to the rhythm of a production line, huge working procedure labor is caused, and the overall production efficiency of the whole plant is seriously reduced; in any case, the replaced old filter bag carries a large amount of sludge and other solid pollutants, which inevitably causes serious secondary pollution and secondary environment-friendly treatment cost, so that a workshop hardly reaches and maintains the 5S production standard;

the second type: generally speaking, although the main disadvantages of the first bag-type liquid filter with manual filter bag replacement are significantly avoided, the automatic liquid filter with self-cleaning and automatic dirt discharge capabilities is limited to the differences in the working principles and structural features of various online automatic liquid filters, and the self-cleaning capabilities of the filter elements are different, so that the stable and high-efficiency working performance and the dirt discharge performance of the existing various automatic liquid filters are different. Some types of automatic liquid filters often work in poor working conditions of low efficiency and high resistance because the filter elements of the automatic liquid filters cannot be cleaned in time, and the discharge capacity of the sludge-containing sewage corresponding to the unit solid filtering capacity is large, so that the automatic liquid filters bring huge adverse effects to the next stage of sludge-containing sewage treatment process and greatly improve the production cost of the whole process.

Thus, there is a need for a high efficiency automatic liquid filter that both self-cleans its filter elements and intermittently automatically drains contaminants.

SUMMERY OF THE UTILITY MODEL

Therefore, the technical problem to be solved by the utility model is to overcome the problems that the liquid filter in the prior art cannot automatically clean the filter element and automatically discharge sewage, or cannot realize high-efficiency automatic filtration with low enough sewage discharge capacity.

In order to solve the technical problem, the utility model provides a self-cleaning and intermittent blowdown automatic liquid filter, which comprises:

the device comprises a barrel, a first positioning plate, a second positioning plate, a first sewage outlet, a second sewage outlet, a first positioning plate and a second positioning plate, wherein the first sewage outlet and the second sewage outlet are arranged at one end of the barrel;

the driving assembly comprises a motor unit and a main shaft connected with the motor unit, and one end of the main shaft, which is far away from the motor unit, penetrates through the first positioning disc and is inserted into the filtering piece;

the cleaning assembly comprises a spring piece arranged at one end of the main shaft inserted into the filter piece, a cleaning piece connected with the spring piece and a cleaning piece arranged at one end of the main shaft far away from the cleaning piece, wherein the cleaning piece is provided with an opening pipe;

the blowdown assembly comprises a blowdown pipeline arranged at one end of the main shaft close to the second positioning plate and a blowdown guide pipe connected with the blowdown pipeline, and the blowdown guide pipe is communicated with the second blowdown port;

the main shaft is driven by the motor to rotate, the cleaning piece and the cleaning piece are driven by the main shaft to synchronously rotate, filter residue blocking objects attached to the inner wall of the filtering piece are scraped by the cleaning piece, and the cleaning piece is tightly attached to the inner wall of the filtering piece in real time under the action of the elastic force of the spring piece; when opening the second drain and carrying out the backwash blowdown, utilize the local liquid reverse pressure difference that the opening pipe of filtering piece and cleaning piece formed, the rotation of following the cleaning piece, rotate local backwash filter piece sedimentary filter residue plug along filtering piece circumferencial direction repeatedly, and simultaneously, the rotation through cleaning piece and cleaning piece drives the inside and outside liquid rotation of filtering piece, the rotation that utilizes liquid in the filtering piece inner chamber washes repeatedly and filters sedimentary filter residue plug, then will contain the leading-in second drain of sewage of filter residue plug through sewage pipes and blowdown pipe, and discharge by the second drain.

As a preferable mode of the utility model, one side of the cylinder body is provided with a sewage inlet, and one side of the cylinder body, which is far away from the sewage inlet, is provided with a clear water outlet.

As a preferred mode of the present invention, the first positioning plate abuts against the inner wall of the cylinder through the first seal ring; the second positioning disc is abutted against the inner wall of the cylinder through a second sealing ring; and the first positioning disc and the second positioning disc are provided with through channels.

As a preferable mode of the utility model, an annular channel is formed between the filter element and the inner wall of the cylinder body; after entering the barrel from the sewage inlet, sewage enters the filtering piece through the channel of the first positioning plate and is filtered from inside to outside under the action of liquid pressure; the filtered clean water passes through an annular channel between the filter element and the inner wall of the cylinder body and is discharged from a clean water outlet; the solid filter residues remained in the sewage in the inner cavity of the filter element also sink in the filter element and are gathered in a sludge settling zone at the bottom of the cylinder body; the first drain port needs to be opened periodically to intermittently drain the precipitated filter residue.

As a preferable mode of the present invention, the motor unit includes a first frame, one end of the first frame, which is away from the cover plate, is provided with a speed reducer, one end of the speed reducer, which is away from the first frame, is provided with a second frame, and one end of the second frame, which is away from the speed reducer, is provided with a motor.

As a preferable mode of the present invention, the motor is connected to a speed reducer through a first coupling, and the speed reducer is connected to the main shaft through a second coupling.

In a preferred embodiment of the present invention, a first bushing is disposed at a connection point of the main shaft and the first positioning plate.

As a preferred mode of the present invention, the sewage conduit is communicated with the filter member; a second shaft sleeve is arranged at one end of the sewage discharge pipeline, which is far away from the main shaft, and one end of the second shaft sleeve is movably connected with the sewage discharge pipeline; and one end of the second shaft sleeve, which is far away from the second positioning plate, is connected with a sewage drainage pipe.

As a preferable mode of the present invention, a sealing gasket is disposed at a connection position of the drain conduit and the second drain outlet.

As a preferable mode of the present invention, a first pressure sampling pipe is disposed on one side of the sewage inlet, and a second pressure sampling pipe is disposed on one side of the clear water outlet.

Compared with the prior art, the technical scheme of the utility model has the following advantages:

the automatic liquid filter capable of self-cleaning and intermittently discharging sewage is suitable for filtering industrial sewage containing micro suspended solids discharged by various industrial production lines, can self-clean the filter element of the industrial sewage, and can intermittently and automatically discharge sewage; and the sewage filtering efficiency is improved, the manual maintenance cost and the consumable consumption cost for replacing the filter bag are reduced, and the time and frequency for shutdown, disassembly and inspection and maintenance are reduced, so that the production efficiency of the production line is improved.

Drawings

In order that the present disclosure may be more readily and clearly understood, reference will now be made in detail to the present disclosure, examples of which are illustrated in the accompanying drawings.

FIG. 1 is a schematic view of a liquid filter of the present invention.

Fig. 2 is a schematic top view of the liquid filter of the present invention.

FIG. 3 is a schematic cross-sectional view of a liquid filter A-A of the present invention.

The specification reference numbers indicate: 1. the device comprises a cylinder body, 10, a sewage inlet, 11, a clean water outlet, 12, a first sewage discharge port, 13, a second sewage discharge port, 14, a first positioning disc, 15, a second positioning disc, 16, a filter element, 20, a cover plate, 21, a first rack, 22, a speed reducer, 23, a second rack, 24, a motor, 25, a first coupler, 26, a second coupler, 31, a first shaft sleeve, 32, a spring element, 33, a cleaning element, 34, a cleaning element, 40, a sewage discharge pipeline, 41, a second shaft sleeve, 42, a sewage discharge conduit, 43, a sealing gasket, 100, a first pressure taking pipe, 110, a second pressure taking pipe, 140, a first sealing ring, 150, a second sealing ring, 300, a first shaft body, 301, a third coupler, 302, a second shaft body, 330 and an opening pipe.

Detailed Description

The present invention is further described below in conjunction with the following figures and specific examples so that those skilled in the art may better understand the present invention and practice it, but the examples are not intended to limit the present invention.

In the description of the present invention, it is to be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", and the like, indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are used only for convenience in describing the present invention and for simplicity in description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, are not to be construed as limiting the present invention. Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "second" or "first" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless specifically defined otherwise.

In the present invention, unless otherwise explicitly stated or limited, the terms "mounted," "connected," "fixed," and the like are to be construed broadly, e.g., as being permanently connected, detachably connected, or integral; the connection can be mechanical connection, electrical connection or communication; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

Unless expressly stated or limited otherwise, the first feature "on" or "under" the second feature may be directly contacting the first and second features, or indirectly contacting the first and second features through intervening media. Furthermore, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements does not include a limitation to the listed steps or elements but may alternatively include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

Referring to fig. 1-3, an embodiment of an automatic liquid filter for self-cleaning and intermittent sewage discharge according to the present invention includes a cylinder 1, wherein a sewage inlet 10 is formed at one side of the cylinder 1, and a first pressure sampling pipe 100 is formed at one side of the sewage inlet 10; a clean water outlet 11 is formed in one side, away from the sewage inlet 10, of the barrel body 1, and a second pressure sampling pipe 110 is arranged on one side, away from the clean water outlet 11, of the barrel body; one end of the barrel body 1 is provided with a first sewage draining port 12, and one end of the barrel body 1, which is close to the first sewage draining port 12, is provided with a second sewage draining port 13.

A first positioning disc 14 is arranged in the cylinder body 1, and the first positioning disc 14 is abutted against the inner wall of the cylinder body 1 through a first sealing ring 140; a second positioning disc 15 is further arranged in the cylinder body 1, and the second positioning disc 15 is abutted against the inner wall of the cylinder body 1 through a second sealing ring 150; the first positioning disc 14 and the second positioning disc 15 are provided with through passages; a filtering piece 16 is arranged between the first positioning disk 14 and the second positioning disk 15, and an annular channel is formed between the filtering piece 16 and the inner wall of the cylinder body 1.

By adopting the technical scheme, through the arrangement of the filtering piece 16, after industrial sewage with high pressure and micro solid suspended matters enters the barrel body 1 from the sewage inlet 10, the industrial sewage enters the filtering piece 16 through the channel of the first positioning disc 14, and is filtered from inside to outside under the action of liquid pressure, wherein the filtered clean water is discharged from the clean water outlet 11 through the annular channel between the filtering piece 16 and the inner wall of the barrel body 1; and the filter residue remained after filtering sinks in the filtering piece 16, so as to gather in the cavity formed at the bottom of the cylinder body 1, and the first sewage discharge port 12 is opened periodically for intermittent sewage discharge.

Preferably, a cover plate 20 is arranged at one end, away from the first sewage discharge port 12 and the second sewage discharge port 13, of the barrel 1, a driving assembly is arranged at one end, away from the barrel 1, of the cover plate 20, the driving assembly comprises a first rack 21, a speed reducer 22 is arranged at one end, away from the cover plate 20, of the first rack 21, a second rack 23 is arranged at one end, away from the first rack 21, of the speed reducer 22, a motor 24 is arranged at one end, away from the speed reducer 22, of the second rack 23, and the motor 24 is connected with the speed reducer 22 through a first coupler 25; the reducer 22 is connected to the main shaft by a second coupling 26.

As shown in fig. 1 and 3, the main shaft includes a first shaft 300 and a second shaft 302, one end of the first shaft 300 is connected to the second coupling 26, and one end of the first shaft 300, which is far away from the second coupling 26, is connected to a third coupling 301; one end of the third coupler 301, which is far away from the first shaft body 300, is connected with the second shaft body 302; the end of the second shaft body 302 far away from the third coupling 301 passes through the first positioning disc 14 and is inserted into the filter element 16; a first shaft sleeve 31 is arranged at the joint of the second shaft body 302 and the first positioning disc 14; the end of the second shaft 302 inserted into the filter element 16 is provided with a plurality of spring elements 32, the end of the spring elements 32 far away from the second shaft 302 is provided with a cleaning element 33, the cleaning element 33 corresponds to the inner wall of the filter element 16, and the cleaning element 33 includes, but is not limited to, a scraper; one end of the cleaning piece 33 close to the filter piece 15 is provided with an open pipe 330; the spring element 32 presses the cleaning element 33 against the inner wall of the filter element 16 by means of a spring force.

As shown in fig. 1 and 3, the end of the second shaft 302 away from the spring element 32 is provided with a cleaning element 34, the cleaning element 34 corresponds to the inner wall of the filter element 16, and the cleaning element 34 includes, but is not limited to, a cleaning brush.

Preferably, a sewage discharge pipeline 40 is arranged at one end of the second shaft body 302 close to the second positioning disc 15, and the sewage discharge pipeline 40 is communicated with the filter element 16; a second shaft sleeve 41 is arranged at one end of the sewage discharge pipeline 40 far away from the second shaft body 302, and one end of the second shaft sleeve 41 is movably connected with the sewage discharge pipeline 40; one end of the second shaft sleeve 41, which is far away from the second positioning plate 15, is provided with a sewage conduit 42, one end of the sewage conduit 42 is communicated with the sewage pipeline 40, the other end of the sewage conduit 42 is communicated with the second sewage outlet 13, and a sealing gasket 43 is arranged at the joint of the sewage conduit 42 and the second sewage outlet 13.

By adopting the above technical scheme, the motor 24 can drive the first shaft 300 to rotate, the second shaft 302 is driven to rotate in the cylinder 1 by the first shaft 300, the cleaning piece 33 and the cleaning piece 34 are driven to rotate by the rotation of the second shaft 302, and then the liquid inside and outside the filtering piece 16 is driven to rotate by the rotation of the cleaning piece 33 and the cleaning piece 34, and the filtered clean water between the outer wall of the filtering piece 16 and the inner wall of the cylinder 1 reversely passes through the filtering piece 16 by the rotation of the liquid, so as to realize the back washing of the filtering piece 16; the arrangement of the spring element 32 and the cleaning element 33 can drive the cleaning element 33 to synchronously rotate when the second shaft body 302 rotates, filter residue blocking objects attached to the inner wall of the filter element 16 are scraped off by the cleaning element 33, and the cleaning element 33 is tightly attached to the inner wall of the filter element 16 in real time under the elastic action of the spring element 32; the cleaning piece 34 is arranged, so that when the main shaft rotates, the cleaning piece 34 is driven to synchronously rotate, and filter residue blocking objects attached to the inner wall of the filter piece 16 are cleaned through the cleaning piece 34; the arrangement of the sewage discharging pipeline 40 and the sewage discharging conduit 42 can lead the filter residue blockage mixed liquid removed by the cleaning piece 33 and the sweeping piece 34 into the second sewage discharging outlet 13 and discharge the filter residue blockage mixed liquid through the second sewage discharging outlet 13.

Preferably, the automatic liquid filter works according to the following principle:

and (3) stabilizing the filtration process:

the industrial sewage with high pressure and tiny solid suspended matters is guided into the sewage inlet 10, then enters the cylinder 1 from the sewage inlet 10, then enters the filter element 16 through the channel of the first positioning disc 14, and is filtered from the inside to the outside of the filter element 16 under the action of liquid pressure;

the filtered clear water passes through an annular channel between the filter piece 16 and the inner wall of the cylinder body 1 and is discharged from the filter outlet 11;

the filter residue remaining after filtration sinks in the interior of the filter element 16 and collects in the cavity formed in the bottom of the cartridge 1.

And (3) a sewage discharge process:

the first drain port 12 is periodically opened to intermittently drain the residue.

Cleaning:

a differential pressure transmitter is arranged between the first pressure sampling pipe 100 and the second pressure sampling pipe 110, and when the differential pressure between the sewage water inlet 10 and the filtering outlet 11 reaches a value preset by an operator, the thickness of the filter residue blocking object on the inner wall of the filtering piece 16 and the filtering resistance reach the value preset by the operator at the moment;

the motor 24 drives the first shaft body 300 to rotate, the first shaft body 300 drives the second shaft body 302 to rotate, the second shaft body 302 further drives the cleaning piece 33 and the cleaning piece 34 to rotate synchronously, the cleaning piece 33 is used for scraping filter residue blocking objects on the inner wall of the filter piece 16, and when the cleaning piece 33 rotates, the spring piece 32 is used for enabling the cleaning piece 33 to be tightly attached to the inner wall of the filter piece 16 in real time;

meanwhile, the cleaning piece 34 is used for cleaning the residues scraped by the cleaning piece 33;

opening the second sewage draining outlet 13 to carry out backwashing sewage draining, and at the moment, utilizing the reverse pressure difference of local liquid formed by the filter element 16 and the opening pipe 330 of the cleaning element 33, along with the rotation of the cleaning element 33, repeatedly rotating along the circumferential direction of the filter element 16 to locally backwash filter residue plugs deposited on the filter element; meanwhile, the liquid inside and outside the filter element 16 is driven to rotate by the rotation of the cleaning element 33 and the sweeping element 34, and the liquid between the outer wall of the filter element 16 and the inner wall of the cylinder 1 reversely passes through the filter element 16 by the rotation of the liquid, so that filter residue blockage deposited on the filter element 16 is backwashed integrally;

after backwashing, the sewage with the filter residue blockage enters the sewage discharge conduit 42 along the sewage discharge pipeline 40, then enters the second sewage discharge outlet 13 through the sewage discharge conduit 42, and is discharged from the second sewage discharge outlet 13.

Preferably, the cleaning element 33 can be replaced by an arc-shaped integral metal knife body with elasticity, and the knife edge is automatically pressed against the inner wall of the filtering element 16 by the elasticity of the arc-shaped knife body, so that the spring element 32 is not required to be additionally installed, the filtering resistance is reduced, the structure of the device is simplified, the manufacturing cost is reduced, and the reliability of the device is improved.

according to the automatic liquid filter capable of self-cleaning and intermittently discharging sewage, the filtering piece 16 is utilized to filter industrial sewage containing micro suspended solids discharged by various industrial production lines in real time, and precipitated filter residues are automatically discharged at regular intervals; after filter residue blockage exists on the inner wall of the filter piece 16, the motor 24, the main shaft, the cleaning piece 33, the spring piece 32 and the cleaning piece 34 are used for working cooperatively, the filter residue blockage on the inner wall of the filter piece 16 is removed, meanwhile, liquid is rotated to carry out back washing on the filter piece 16, then sewage containing the filter residue blockage is discharged through the second sewage outlet 13 by utilizing the sewage discharge pipeline 40 and the sewage discharge guide pipe 42, the manual maintenance cost and the filter bag replacement consumable consumption cost are reduced, the time and frequency of shutdown, disassembly and maintenance are reduced, and the production efficiency of a production line is improved.

It should be understood that the above examples are only for clarity of illustration and are not intended to limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. And obvious variations or modifications of the utility model may be made without departing from the spirit or scope of the utility model.

Claims

1. An automatic liquid filter for self-cleaning and intermittent blowdown, comprising:

the cleaning assembly comprises a spring part arranged at one end of the main shaft inserted into the filter element, a cleaning element connected with the spring part and a cleaning element arranged at one end of the main shaft far away from the cleaning element, wherein an open pipe is arranged at one end of the cleaning element close to the filter element;

the main shaft is driven by the motor to rotate, the cleaning piece and the sweeping piece are driven by the main shaft to synchronously rotate, filter residue blocking objects attached to the inner wall of the filter piece are scraped by the cleaning piece, and the cleaning piece is tightly attached to the inner wall of the filter piece in real time under the elastic action of the spring piece; when opening the second drain and carrying out the backwash blowdown, utilize the local liquid reverse pressure difference that the opening pipe of filtering piece and cleaning member formed, along with the rotation of cleaning member, rotate along filtering a circumferencial direction repeatedly, local backwash filters a sedimentary filter residue plug, and simultaneously, the rotation through cleaning member and cleaning member drives the inside and outside liquid rotation of filtering piece, utilize the rotation of liquid in the filtering piece inner chamber to wash repeatedly and filter a sedimentary filter residue plug, then will contain the leading-in second drain of sewage of filter residue plug through sewage pipes and blowdown pipe, and discharge by the second drain.

2. A self-cleaning and intermittent blowdown automatic liquid filter as claimed in claim 1, wherein a sewage inlet is provided to one side of said cylinder, and a filtered clean water outlet is provided to a side of said cylinder remote from said sewage inlet.

3. A self-cleaning and intermittent waste discharge automatic liquid filter as claimed in claim 1, wherein the first positioning disc is abutted against the inner wall of the cylinder body through a first sealing ring; the second positioning disc is abutted against the inner wall of the cylinder through a second sealing ring; and the first positioning disc and the second positioning disc are provided with through channels.

4. A self-cleaning and intermittent blowdown automatic liquid filter as claimed in claim 3, wherein an annular passage is formed between said filter element and the inner wall of the cartridge body; after entering the barrel from the sewage inlet, sewage enters the filtering piece through the channel of the first positioning plate and is filtered from inside to outside under the action of liquid pressure; the filtered clean water passes through an annular channel between the filter element and the inner wall of the cylinder body and is discharged from a clean water outlet; the filter residue left after filtration sinks in the interior of the filter piece and gathers at the bottom of the barrel body; and the first drain outlet is opened periodically to discharge the precipitated filter residue intermittently.

5. A self-cleaning and intermittent blowdown automatic liquid filter as claimed in claim 1, wherein said motor unit includes a first frame, a speed reducer is provided at an end of said first frame remote from the cover plate, a second frame is provided at an end of said speed reducer remote from the first frame, and a motor is provided at an end of said second frame remote from the speed reducer.

6. The automatic liquid filter for self-cleaning and intermittent blowdown of claim 5, wherein the motor is coupled to a speed reducer through a first coupling, the speed reducer being coupled to the main shaft through a second coupling.

7. A self-cleaning and intermittent blowdown automatic liquid filter as claimed in claim 1, wherein a first bushing is provided at the junction of the main shaft and the first positioning disk.

8. A self-cleaning and intermittent drain automatic liquid filter according to claim 1, wherein said drain conduit is in communication with a filter element; a second shaft sleeve is arranged at one end of the sewage discharge pipeline, which is far away from the main shaft, and one end of the second shaft sleeve is movably connected with the sewage discharge pipeline; and one end of the second shaft sleeve, which is far away from the second positioning plate, is connected with a sewage drainage pipe.

9. A self-cleaning and intermittent waste discharge automatic liquid filter as claimed in claim 8 wherein a sealing gasket is provided at the junction of the waste conduit and the second waste discharge outlet.

10. An automatic liquid filter for self-cleaning and intermittent blowdown according to claim 2, wherein a first pressure pipe is provided at one side of the blowdown inlet port and a second pressure pipe is provided at one side of the fresh water outlet port.