CN220939293U - Duckweed filter equipment for river course sewage treatment - Google Patents

Abstract

The utility model relates to a duckweed filter device for river sewage treatment, which belongs to the technical field of river sewage treatment and comprises a filter cartridge, wherein the upper end of the filter cartridge is open; the filter cartridge is internally provided with a filter screen which can move relative to the inner wall of the filter cartridge; the filter cylinder is provided with a water inlet which is positioned above the filter screen, and duckweed can be filtered above the filter screen; the filter cartridge is provided with a water outlet which is positioned below the filter screen; the filter cartridge is provided with a driving component for driving the filter cartridge to move; the upper surface wall of the filter screen can be leveled with the upper surface wall of the filter cartridge under the drive of the drive assembly; the upper end of the filter cartridge is fixed with a mounting frame, a scraping motor is arranged on the mounting frame, a scraping plate is fixed on a rotating shaft of the scraping motor, the scraping plate rotates around the axis of the filter screen under the driving of the scraping motor, and the lower surface wall of the scraping plate is leveled with the upper surface wall of the filter cartridge. The device can treat duckweed by means of machinery when duckweed is piled on the surface wall of the filter screen.

Description

Duckweed filter equipment for river course sewage treatment

Technical Field

The utility model relates to the technical field of river sewage treatment, in particular to a duckweed filter device for river sewage treatment.

Background

In river sewage test, the problem of influence of ammonia, nitrogen and phosphorus proportion and environmental temperature of river sewage needs to be explored, and students generally directly take the river sewage from nearby river channels.

Some aquatic plants such as duckweed can exist in river sewage, and the common diameter is tens of millimeters to centimeters. In order to avoid the influence of duckweed on the experiment of the influence of the ammonia, nitrogen and phosphorus proportions of the river sewage and the environmental temperature, the duckweed in the river sewage needs to be filtered before the experiment.

The conventional way of filtering duckweed is: a filter cartridge is provided, and a filter screen is arranged in the filter cartridge. During filtration, river sewage is introduced into the filter cartridge, and duckweed is filtered on the upper surface wall of the filter screen. The filter cartridge is provided with a water outlet, the water outlet is positioned below the filter screen, and river sewage after the duckweed is filtered is discharged out of the filter cartridge from the water outlet. The filter device has the defects that after duckweed is filtered on the filter screen, the duckweed is piled up to cover the filter holes of the filter screen, so that the river sewage is influenced to continue to filter the duckweed, after a certain amount of river sewage is filtered, students need to manually clean the duckweed on the filter screen, and the duckweed cannot be mechanically cleaned.

Disclosure of utility model

The utility model relates to a duckweed filter device for river sewage treatment, which can mechanically treat duckweed on a filter screen.

In order to achieve the above purpose, the duckweed filter device for river sewage treatment comprises a filter cartridge, wherein the upper end of the filter cartridge is open; the filter cartridge is internally provided with a filter screen which can move relative to the inner wall of the filter cartridge; the filter cylinder is provided with a water inlet which is positioned above the filter screen, and duckweed can be filtered above the filter screen; the filter cartridge is provided with a water outlet which is positioned below the filter screen; the filter cartridge is provided with a driving component for driving the filter cartridge to move; the upper surface wall of the filter screen can be leveled with the upper surface wall of the filter cartridge under the drive of the drive assembly; the upper end of the filter cartridge is fixed with a mounting frame, a scraping motor is arranged on the mounting frame, a scraping plate is fixed on a rotating shaft of the scraping motor, the scraping plate rotates around the axis of the filter screen under the driving of the scraping motor, and the lower surface wall of the scraping plate is leveled with the upper surface wall of the filter cartridge.

Further, the driving assembly comprises a rotating rod, the rotating rod is arranged along the radial direction of the filter cartridge, and the rotating rod is connected to the filter cartridge in a rotating way; one end of the rotating rod corresponding to the rotating rod extends into the filter cartridge; one end of the rotating rod extending into the filter cartridge is sleeved with a cam, and the cam is fixedly connected with the rotating rod; a vertical rod is arranged below the filter screen, one end of the vertical rod is fixedly connected with the lower surface wall of the filter screen, and the other end of the vertical rod is provided with a connecting plate which is fixedly connected with the vertical rod; the upright rod and the connecting plate do not block sewage from the water inlet to the water outlet; the cam is arranged below the connecting plate, the cam is in butt joint with the connecting plate, and a servo motor for driving the rotating rod to rotate is arranged on the outer wall of the filter cylinder.

The servo motor is used for driving, and because the servo motor is accurately controlled, the rotation in a small angle can be realized; because can realize the rotation of low-angle, so can control servo motor's rotation accurately, let the long end or the short end of cam accurately with even the board butt, ensure under drive assembly's drive, the upper surface wall of filter screen can be with the lower surface wall contact of scraper blade.

Further, a connecting ring is connected to the filter cartridge, the connecting ring is positioned in the filter cartridge, the upper surface wall of the connecting ring is fixedly connected with a guide rod, a connecting plate is sleeved on the guide rod, and the connecting plate can move along the guide rod; the cam is abutted with the connecting plate through a hole in the middle of the connecting ring.

The guide rod is utilized to provide a guide effect for the movement of the filter screen, so that the filter screen can not rotate around the axis of the filter screen, and the cam can not be worn due to the rotation between the cam and the connecting rod, thereby being beneficial to prolonging the service life of the cam.

Further, a plurality of placing grooves are formed in the peripheral wall of the filter cartridge, supporting rods are arranged in the placing grooves, and the supporting rods are arranged in one-to-one correspondence with the placing grooves; the plurality of support rods are fixedly connected with the connecting ring; the placement groove extends downwards from the upper end of the filter cartridge; a plug board is arranged in the placing groove; the height sum of the plug plate and the supporting rod is equal to the height of the placing groove; the plug board and the supporting rod seal the placing groove, and the plug board is positioned above the supporting rod; the upper surface wall of the plug plate is abutted with the screw cap of the long bolt.

Through setting up the standing groove, can let cock plate, bracing piece, go-between, link, pole setting and filter screen as whole, upwards move to break away from through the standing groove upper end, play the effect of dismantling. The filter screen is in inconvenient taking out in the cartridge filter, through setting up bracing piece and go-between, can let the filter screen take out from the cartridge filter earlier, dismantle again, even not use the instrument, also can take out the cartridge filter with the filter screen comparatively smoothly.

Further, the end face of the connecting plate is triangular; the lower surface wall of the connecting plate is a plane, and the lower surface wall of the connecting plate is abutted with the cam.

The connecting plate is arranged into a triangle, so that the upper end of the connecting plate is two inclined planes, sewage is guided by the two inclined planes after contacting the upper end of the connecting plate, the sewage cannot be detained on the upper surface wall of the connecting plate, the weight increase of the connecting plate caused by the detained sewage is avoided as much as possible, and the resistance of the servo motor to the movement of the connecting plate is reduced.

Further, the filter device further comprises a collection tank in which the filter cartridge is placed.

The duckweed thrown out can be collected into the collecting tank as much as possible, and the duckweed can not splash everywhere, so that the duckweed can be intensively treated, and the pollution to a test area is reduced.

Advantageous effects

1. The device is provided with a cam and a servo motor, when duckweed on the wall of the filter screen is required to be treated, the cam is driven by the servo motor, so that the filter screen is abutted by the cam to rise, the upper surface wall of the filter screen is leveled with the upper surface wall of the filter cartridge, the scraping motor is started, and the scraping plate scrapes the duckweed on the filter screen; the servo motor resets the cam to re-filter the duckweed on the filter screen mechanically.

2. The filter cartridge is characterized by comprising a placing groove, a supporting rod and a connecting ring, wherein when the filter cartridge is disassembled, the scraping motor is disassembled firstly, the connecting plate, the vertical rod and the filter screen are taken out as a whole through the supporting rod and the connecting ring, and then the connecting plate, the vertical rod and the filter screen are separated from the connecting ring, so that the filter screen can be taken out without tools, and the filter cartridge is convenient to disassemble.

Drawings

FIG. 1 is a schematic view of the overall structure of the device;

FIG. 2 is a cross-sectional view of the device taken vertically and with the mounting frame omitted;

FIG. 3 is a schematic view of the structure of the link plate;

FIG. 4 is a schematic view showing the structure of the whole of the support rod, the connecting ring and the guide rod;

fig. 5 is a schematic view showing a state of the filter net when the duckweed is cleaned.

Reference numerals: 1. a filter cartridge; 2. a placement groove; 3. a support rod; 4. a connecting ring; 5. a plug plate; 6. a long bolt; 7. a guide rod; 8. a connecting plate; 9. a vertical rod; 10. a filter screen; 11. a rotating lever; 12. a cam; 13. a water inlet; 14. a water outlet; 15. a mounting frame; 16. a scraping motor; 17. a scraper; 18. and (5) a collecting tank.

Detailed Description

For the purpose of making the objects, technical solutions and advantages of the embodiments of the present utility model more apparent, the technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings, and it is apparent that the described embodiments are some embodiments of the present utility model, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the utility model without making any inventive effort, are intended to be within the scope of the utility model.

Referring to fig. 1, a duckweed filter device for river sewage treatment comprises a filter cartridge 1, wherein the filter cartridge 1 is a cylinder in the embodiment, and other shapes can be adopted in other embodiments. The cartridge filter 1 axis is vertical to be set up, and the drum is equipped with spaciously, and other table walls are closed setting.

Referring to fig. 2, at least two placement grooves 2 are formed in the peripheral wall of the filter cartridge 1, and the placement grooves 2 are arranged to extend downwards from the upper end of the filter cartridge 1, i.e., the upper end of the placement groove 2 is provided with a notch. The placement groove 2 penetrates through the wall of the filter cartridge 1 along the radial direction of the filter cartridge 1.

See fig. 2 and 4, all be equipped with bracing piece 3 in the standing groove 2, bracing piece 3 and standing groove 2 one-to-one set up, and bracing piece 3 is in corresponding standing groove 2, and bracing piece 3 places the lower extreme at corresponding standing groove 2, namely, the lower table wall butt of bracing piece 3 and the lower table wall of standing groove 2. The plurality of support rods 3 are jointly provided with a connecting ring 4, the shape of the connecting ring 4 is a circular ring, and the axis of the connecting ring 4 coincides with the axis of the filter cartridge 1. The external diameter of the connecting ring 4 is consistent with the internal diameter of the filter cartridge 1, and the circumferential external wall of the connecting ring 4 is fixedly connected with a plurality of support rods 3.

When dismantling bracing piece 3, under the staff effect, bracing piece 3 can be along vertical for standing groove 2 removal, go up the ring 4 and also remove along with the removal of bracing piece 3, go up the ring 4 and can be along vertical for the inner wall of cartridge filter 1, and in the removal process, the outer wall of go up the ring 4 is attached with the inner wall of cartridge filter 1.

See fig. 2, be equipped with the cock plate 5 in the standing groove 2, cock plate 5 and bracing piece 3 one-to-one set up, and cock plate 5 movable card is established in standing groove 2, and cock plate 5 can follow vertical movement, and cock plate 5 is in the top of bracing piece 3, and the lower table wall butt of cock plate 5 and the last table wall of bracing piece 3. The sum of the heights of the plug plate 5 and the support rod 3 along the axis of the filter cartridge 1 is equal to the height of the placing groove 2. The width of the plug plate 5 and the width of the supporting rod 3 in the horizontal direction are equal to the width of the placing groove 2, and when the plug plate 5 and the supporting rod 3 are positioned in the placing groove 2, the placing groove 2 can be completely closed by the plug plate 5 and the supporting rod 3, and the filter cartridge 1 cannot leak water due to the placing groove 2.

The plug plate 5 can be separated from the filter cartridge 1 from the upper end of the placement groove 2 by vertical movement; similarly, after the plug plate 5 is separated from the placement groove 2, the limit of the plug plate 5 on the support rod 3 is lost, and the support rod 3 and the connecting ring 4 can also vertically move as a whole and separate from the filter cartridge 1 from the upper end of the placement groove 2.

The plug board 5 is provided with a plurality of long bolts 6, the long bolts 6 are arranged in one-to-one correspondence with the plug board 5, the axes of the long bolts 6 are arranged vertically, and the long bolts 6 are arranged on the plug board 5 in a penetrating way; the lower end of the long bolt 6 passes through the plug plate and also passes through the supporting rod 3, and the plug plate 5 and the supporting rod 3 are provided with holes for the long bolt 6 to pass through; the lower end portion of the long bolt 6 is screwed into the side wall of the filter cartridge 1, and the nut lower end of the long bolt 6 abuts against the upper surface wall of the plug 5. The plug plate 5 and the support rod 3 are fixedly connected through the long bolt 6, and the plug plate 5, the support rod 3 and the connecting ring 4 are all fixed on the filter cartridge 1.

Referring to fig. 2 and 4, at least one guide rod 7 is fixedly connected to the upper surface wall of the connection ring 4, and the axis of the guide rod 7 is parallel to the axis of the filter cartridge 1. The guide rod 7 is positioned in the filter cartridge 1, and when the connection ring 4 and the support rod 3 are moved upward as a whole, the guide rod 7 is also moved upward in the filter cartridge 1.

The guide rod 7 is sleeved with a connecting plate 8, the lower surface wall of the connecting plate 8 is abutted with the upper surface wall of the connecting ring 4, namely the connecting plate 8 is placed on the connecting ring 4. The outer wall of the connecting plate 8 does not close the inner wall of the filter cartridge 1, that is, a gap is left between the peripheral wall of the connecting plate 8 and the inner wall of the connecting ring 4, and the gap is arranged in two directions perpendicular to the paper surface in fig. 2, so that river sewage can flow through the connecting plate 8 from top to bottom through the gap. The connecting plate 8 can move vertically relative to the guide rod 7, and the connecting plate 8 cannot rotate around the axis of the filter cartridge 1 and can only move vertically along the axis of the guide rod 7 under the restriction of the guide rod 7.

Referring to fig. 3, in order to facilitate the water flow of the upper surface wall of the connecting plate 8, the upper surface wall of the connecting plate 8 does not remain river sewage, the end surface of the connecting plate 8 is triangular, and the lower surface wall is a plane for abutting against the surface wall of the connecting ring 4; the upper surface wall consists of two inclined planes, and the middle of the upper surface wall is high and the two sides of the upper surface wall are low.

Referring to fig. 3, the upper end of the connecting plate 8 is fixedly connected with a vertical rod 9, and the axis of the vertical rod 9 coincides with the axis of the filter cartridge 1. The upper end of the upright rod 9 is fixedly connected with a rigid filter screen 10, the diameter of the filter screen 10 is smaller than that of the smallest duckweed, the diameter of the duckweed is generally from tens of millimeters to centimeters, and the aperture of the filter screen 10 is 4-8 millimeters. The axis of the filter screen 10 coincides with the axis of the filter cartridge 1, and the filter screen 10 is in the filter cartridge 1, and the circumferential outer wall of the filter screen 10 is attached to the inner wall of the filter cartridge 1. The filter screen 10 can move with the movement of the link plate 8. The filter screen 10 is positioned above the guide rod 7.

Referring to fig. 2, a rotary rod 11 is rotatably connected to the filter cartridge 1 by means of a bearing, the axis of the rotary rod 11 is arranged along the radial direction of the filter cartridge 1, the corresponding end of the rotary rod 11 extends into the filter cartridge 1, a cam 12 is arranged at one end of the rotary rod 11 in the filter cartridge 1, the cam 12 is sleeved on the rotary rod 11, and the cam 12 is fixedly connected with the rotary rod 11. The cam 12 is located below the link plate 8, and the peripheral wall of the cam 12 abuts against the lower surface wall of the link plate 8 through a hole in the middle of the link ring 4.

Referring to fig. 5, when the long end of the cam 12 abuts against the lower surface wall of the connecting plate 8, the upper surface wall of the filter screen 10 is exactly flush with the upper surface wall of the filter cartridge 1. The rotating rod 11 is driven to rotate by a servo motor, a rotating shaft of the servo motor and the rotating rod 11 are coaxially arranged and fixedly connected, a non-rotating shaft end of the servo motor is fixed on the outer wall of the filter cartridge 1, and the servo motor is controlled by a single chip microcomputer and stops after rotating 180 degrees each time. In the initial state, the short end of the cam 12 abuts against the lower surface wall of the link plate 8, see fig. 2.

Referring to fig. 2, a water inlet 13 is formed in a filter cartridge 1, a water inlet pipe is fixed on the filter cartridge 1, and the water inlet pipe is inserted into the water inlet 13; in the initial state, the water inlet 13 is positioned above the filter screen 10. The filter cartridge 1 is also provided with a water outlet 14, the filter cartridge 1 is fixedly connected with a water outlet pipe, the water outlet pipe is inserted into the water outlet 14, and the water outlet 14 is positioned below the filter screen 10.

Referring to fig. 1, an upper surface wall of a filter cartridge 1 is fixed with a mounting frame 15 through bolts, a scraping motor 16 is arranged on the mounting frame 15, a non-rotating shaft end of the scraping motor 16 is fixed on the upper surface wall of the mounting frame 15, a rotating shaft of the scraping motor 16 penetrates through the mounting frame 15, and a rotating shaft axis of the scraping motor 16 coincides with an axis of the filter cartridge 1. Referring to fig. 1 and 2, a scraper 17 is fixedly connected to a rotating shaft of the scraping motor 16, the length of the scraper 17 along the radial direction of the filter cartridge 1 is slightly smaller than the inner diameter of the filter cartridge 1, the lower surface wall of the scraper 17 is leveled with the upper surface wall of the filter cartridge 1, and the scraping motor 16 can drive the scraper 17 to rotate around the axis of the filter cartridge 1.

Referring to fig. 1, a collecting tank 18 is arranged below the filter cartridge 1, an opening is formed above the collecting tank 18, and the filter cartridge 1 is placed in the filtering tank.

The using process comprises the following steps:

S1: connecting a water inlet pipe with a water outlet end of a water pump through a hose, connecting the water inlet end of the water pump with a water tank filled with river sewage through another hose, starting the water pump, and sucking the river sewage (including duckweed) in the water tank into the filter cartridge 1 from the water inlet pipe by the water pump; in the initial state (i.e., the state of fig. 2), since the water inlet 13 is located above the filter screen 10, the river sewage reaches above the filter screen 10, and the filter screen 10 filters duckweed in the river sewage.

S2: the river sewage with most duckweed filtered (possibly a very small amount of duckweed is left, the influence on the test is negligible, so that the river sewage is considered to be treated with all duckweed) flows through the filter screen 10 from the upper end of the filter screen 10 under the self gravity, the diameter of the upright rod 9 is far smaller than that of the filter cartridge 1, so that the upright rod 9 cannot block the river sewage (the duckweed is removed), in addition, a gap is left between the connecting plate 8 and the middle hole of the connecting ring 4, so that the connecting plate 8 cannot block the river sewage (the duckweed is removed), the river sewage (the duckweed is removed) flows to the water outlet 14, the water outlet 14 is connected with the receiving box through the water outlet pipe, and finally the river sewage (the duckweed is removed) flows to the collecting box, and the collecting box is used for collecting the river sewage (the duckweed is removed) for the test by students.

S3: when more duckweed is accumulated on the filter screen 10, students subjectively think that the duckweed on the filter screen needs to be treated; first, the water pump is turned off, and water injection into the filter cartridge 1 is stopped. Then, the student manually starts the servo motor once, and the servo motor is controlled by the singlechip to rotate 180 degrees and then self-locks and stops (the cam 12 is in the state of fig. 5), and at the moment, the long end of the cam 12 is abutted with the lower surface wall of the connecting plate 8. The cam 12 is against the connecting plate 8 forcing the connecting plate 8, the uprights 9 and the filter screen 10 as a whole upwards, eventually the upper surface wall of the filter screen 10 being level with the upper end of the filter cartridge 1.

S4: the student manually starts the scraping motor 16, and the scraping plate 17 rotates around the axis of the filter cartridge 1 under the action of the scraping motor 16, and the lower surface wall of the scraping plate 17 is leveled with the upper surface wall of the filter screen 10 because the lower surface wall of the scraping plate 17 is leveled with the upper end of the filter cartridge 1. By the rotation of the scraper 17, the duckweed is scraped by the scraper 17 against the side wall of the scraper 17, instead of being stuck to the upper surface wall of the filter screen 10. The duckweed on the side wall of the scraper 17 is thrown around in the radial direction of the filter cartridge 1 due to the centrifugal force generated by the rotation of the scraper 17, and the greater the rotation speed of the scraper 17, the more easily the duckweed is thrown around the filter cartridge 1. The duckweed thrown around the filter cartridge 1 falls into the collecting tank 18, and the duckweed is concentrated and treated by the collecting tank 18.

S5: after the students subjectively think that duckweed on the filter screen 10 is processed, the students manually stop the scraping motor 16, the students manually start the servo motor once, the servo motor is controlled by the singlechip to rotate 180 degrees and then self-lock and stop, the short end of the cam 12 is abutted with the lower surface wall of the connecting plate 8, the filter screen 10, the upright rod 9 and the connecting plate 8 are lowered by gravity (in the state of fig. 2), and the water inlet 13 is positioned above the filter screen 10 again. The scraper 17 no longer abuts the upper surface wall of the filter screen 10.

S6: repeating S1-S5, the filter screen 10 can continue to filter river sewage (including duckweed).

Disassembly process

S1: the bolts for connecting the mounting frame 15 with the filter cartridge 1 are removed, and the mounting frame 15, the scraping motor 16 and the scraping plate 17 are taken as a whole, so that the filter cartridge 1 is removed.

S3: removing the long bolt 6 to enable the plug plate 5, the support rod 3 and the filter cartridge 1 to lose connection; removing the plug 5 from the upper end of the placement tank 2 from the filter cartridge 1; the support rod 3, the connecting ring 4, the guide rod 7, the connecting plate 8, the upright rod 9 and the filter 10 are separated from the filter cartridge 1 upwards as a whole.

S4: and then the connecting plate 8, the vertical rod 9 and the filter 10 are taken as a whole and are separated from the guide rod 7 upwards, so that the whole disassembly is completed.

The installation process is opposite to the disassembly process, and will not be described again.

With the above-described preferred embodiments according to the present utility model as an illustration, the above-described descriptions can be used by persons skilled in the relevant art to make various changes and modifications without departing from the scope of the technical idea of the present utility model. The technical scope of the present utility model is not limited to the description, but must be determined according to the scope of claims.

Claims (6)

1. The duckweed filter device for river sewage treatment is characterized by comprising a filter cartridge, wherein the upper end of the filter cartridge is open; the filter cartridge is internally provided with a filter screen which can move relative to the inner wall of the filter cartridge; the filter cylinder is provided with a water inlet which is positioned above the filter screen, and duckweed can be filtered above the filter screen; the filter cartridge is provided with a water outlet which is positioned below the filter screen; the filter cartridge is provided with a driving component for driving the filter cartridge to move; the upper surface wall of the filter screen can be leveled with the upper surface wall of the filter cartridge under the drive of the drive assembly; the upper end of the filter cartridge is fixed with a mounting frame, a scraping motor is arranged on the mounting frame, a scraping plate is fixed on a rotating shaft of the scraping motor, the scraping plate rotates around the axis of the filter screen under the driving of the scraping motor, and the lower surface wall of the scraping plate is leveled with the upper surface wall of the filter cartridge.

2. The duckweed filter device for river sewage treatment according to claim 1, wherein said driving assembly comprises a rotation rod disposed along the radial direction of the filter cartridge, the rotation rod being rotatably connected to the filter cartridge; one end of the rotating rod corresponding to the rotating rod extends into the filter cartridge; one end of the rotating rod extending into the filter cartridge is sleeved with a cam, and the cam is fixedly connected with the rotating rod; a vertical rod is arranged below the filter screen, one end of the vertical rod is fixedly connected with the lower surface wall of the filter screen, and the other end of the vertical rod is provided with a connecting plate which is fixedly connected with the vertical rod; the upright rod and the connecting plate do not block sewage from the water inlet to the water outlet; the cam is arranged below the connecting plate, the cam is in butt joint with the connecting plate, and a servo motor for driving the rotating rod to rotate is arranged on the outer wall of the filter cylinder.

3. The duckweed filter device for river sewage treatment according to claim 2, wherein the filter cartridge is connected with a connecting ring, the connecting ring is positioned in the filter cartridge, the upper surface wall of the connecting ring is fixedly connected with a guide rod, the connecting plate is sleeved on the guide rod, and the connecting plate can move along the guide rod; the cam is abutted with the connecting plate through a hole in the middle of the connecting ring.

4. The duckweed filter device for river sewage treatment according to claim 3, wherein a plurality of placing grooves are formed in the peripheral wall of the filter cartridge, supporting rods are arranged in the placing grooves, and the supporting rods are arranged in one-to-one correspondence with the placing grooves; the plurality of support rods are fixedly connected with the connecting ring; the placement groove extends downwards from the upper end of the filter cartridge; a plug board is arranged in the placing groove; the height sum of the plug plate and the supporting rod is equal to the height of the placing groove; the plug board and the supporting rod seal the placing groove, and the plug board is positioned above the supporting rod; the upper surface wall of the plug plate is abutted with the screw cap of the long bolt.

5. A duckweed filter device for river sewage treatment according to claim 3, wherein the end surface of said connecting plate is triangular; the lower surface wall of the connecting plate is a plane, and the lower surface wall of the connecting plate is abutted with the cam.

6. The duckweed filter device for river sewage treatment of claim 1, further comprising a collecting tank, wherein the filter cartridge is placed in the collecting tank.