Tap water secondary purification device

Abstract

The invention relates to the technical field of tap water treatment, and particularly discloses a tap water secondary purification device which comprises a shell and a partition plate, a mounting hole is formed in the middle of the top side of the shell, a rotating first water pipe is mounted in the mounting hole, the inner wall of the shell is fixedly connected with the edge of the partition plate, and an inner cavity of the shell is divided into a raw water cavity and a purified water cavity by the partition plate; a water inlet communicated with the raw water cavity is formed in the shell, a water outlet communicated with the water purification cavity is formed in the shell, a plurality of open holes are formed in the partition plate around the first water pipe at equal angles, a tubular filter element is arranged in each open hole in a penetrating mode, and the peripheral side of each tubular filter element is attached to the inner wall of the corresponding open hole in a sliding and sealing mode; the tap water secondary purification device purifies tap water before the tap water enters a home, the situation that the purification work of the tap water affects daily life of residents is avoided, backwashing can be achieved without cutting off water, the stability and continuity of tap water supply are guaranteed, and inconvenience or loss caused by water cutting off is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of tap water treatment, in particular to a tap water secondary purification device. Background Art

[0002] Tap water is an indispensable resource in residents' daily lives, and the water quality safety of tap water is directly related to people's health. However, in the process of transporting tap water from the water plant to the community, there is a risk of tap water being contaminated: the water supply pipes in many cities in my country are made of traditional materials such as iron pipes and galvanized pipes. These pipes are prone to aging and rust after years of use, resulting in rough inner walls of the pipes, which are easy to breed bacteria and microorganisms; some tap water pipes were built at an early age and have not been repaired or replaced for a long time. A large amount of rust, mud and other impurities are attached to the inner walls of the pipes, affecting the water quality; many communities use rooftop water towers or underground water tanks for secondary water supply. If the rooftop water towers or underground water tanks are not cleaned and disinfected for a long time, dust and impurities are likely to accumulate.

[0003] In the prior art, each household usually installs a water purifier at home. Regular maintenance and backwashing of the water purifier take up time and affect the daily life of residents. Summary of the invention

[0004] The technical problem to be solved by the present invention is to overcome the existing defects and provide a tap water secondary purification device to purify tap water before it enters the household, so as to avoid the tap water purification operation affecting the daily life of residents, and to achieve backwashing without stopping the water supply, thereby ensuring the stability and continuity of the tap water supply and reducing the inconvenience or loss caused by water outage.

[0005] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a tap water secondary purification device, comprising an internally hollow shell and a partition located in the inner cavity of the shell, a mounting hole is opened in the middle of the top side of the shell, a rotating first water pipe is installed in the mounting hole, the inner wall of the shell and the edge of the partition are fixedly sealed and connected, the partition divides the inner cavity of the shell into a raw water cavity and a clean water cavity, and the raw water cavity is located above the clean water cavity, a water inlet connected to the raw water cavity is opened on the shell, a water outlet connected to the clean water cavity is opened on the shell, a plurality of openings are opened on the partition at equal angles around the first water pipe, a tubular filter element is penetrated in each opening, the outer peripheral side of the tubular filter element and the inner wall of the opening are slidingly sealed and fitted, the bottom end of the tubular filter element and the bottom side of the inner cavity of the shell are detachably connected, and the top end of the tubular filter element is lower than the top side of the partition.

[0006] A plurality of sixth water pipes are arranged around the bottom end of the first water pipe, and the number of the sixth water pipes is less than the number of the openings. The bottom end of the first water pipe is connected to one end of the sixth water pipe, and the other end of the sixth water pipe is slidably fitted to the top side of the partition.

[0007] When the number of the sixth water pipes is not less than two, the interval angle between any two sixth water pipes around the first water pipe is an integer multiple of the interval angle between two adjacent openings around the first water pipe.

[0008] Among them, the backwashing operation is: rotating the first water pipe so that the sixth water pipe completely covers the opening.

[0009] Among them, the recovery operation after backwashing is: rotating the first water pipe to separate the sixth water pipe from the opening.

[0010] As a preferred technical solution of the present invention, it also includes a second water pipe and a water pool, the second water pipe has a first end and a second end, and the first end of the second water pipe is higher than the second end of the second water pipe, the second end of the second water pipe and the top end of the first water pipe are connected through a rotating joint, the first end of the second water pipe is connected to the top end of the fourth water pipe, the inner cavity of the second water pipe is connected to the top end of the third water pipe, the third water pipe is located between the first water pipe and the fourth water pipe, the top of the inner cavity of the second water pipe near the first end of the second water pipe is connected to one end of the fifth water pipe, the other end of the fifth water pipe is connected to the middle of the inner cavity of the third water pipe, and the bottom ends of the third water pipe and the fourth water pipe both extend into the inner cavity of the water pool.

[0011] As a preferred technical solution of the present invention, a rotating shaft is coaxially installed in the inner cavity of the tubular filter element, a spiral blade is installed on the rotating shaft, and the edge of the spiral blade is slidably fitted with the inner wall of the tubular filter element.

[0012] As a preferred technical solution of the present invention, a cavity is provided inside the rotating shaft, a first through hole connected to the cavity is opened at the top end of the rotating shaft, and a second through hole connected to the cavity is opened at the bottom end of the rotating shaft.

[0013] As a preferred technical solution of the present invention, the spiral blades are made of elastic rubber material or elastic plastic material.

[0014] As a preferred technical solution of the present invention, an opening valve connected to the inner cavity of the second water pipe is installed at the top of the outer side of the second water pipe near the first end of the second water pipe, and the ratio of the valve cross-sectional area of ​​the opening valve to the cross-sectional area of ​​the inner cavity of the third water pipe is 1.0:30.0-100.0.

[0015] As a preferred technical solution of the present invention, a limiting mechanism is installed on the top side of the shell, and the limiting mechanism includes a chuck coaxially fixed on the first water pipe and a fixed block fixed on the top side of the shell, a sliding slide rod is installed on the fixed block, one end of the slide rod is against the edge of the chuck, and an elastic part for pushing the slide rod to move toward the chuck is installed on the fixed block.

[0016] As a preferred technical solution of the present invention, a plurality of slots are provided at equal angles on the edge of the chuck.

[0017] As a preferred technical solution of the present invention, the chuck is fixedly connected to one end of the gripping rod.

[0018] As a preferred technical solution of the present invention, a rotating ring is installed at a position of the sixth water pipe away from the first water pipe, a brush is fixed on the bottom side of the rotating ring, the brush abuts against the top side of the partition, and the edge of the rotating ring abuts against the inner wall of the shell.

[0019] Compared with the prior art, the present invention has the following beneficial effects: 1. In the tap water secondary purification device exemplified by the present invention, the staff makes each sixth water pipe blocked with an opening, and some of the openings are not blocked by the sixth water pipe. The water flow at the tubular filter element below the sixth water pipe flows from outside to inside to realize backwashing of the tubular filter element. The tap water secondary purification device realizes backwashing of the tubular filter element without stopping the water supply, thereby ensuring the stability and continuity of the tap water supply and reducing the inconvenience or loss caused by water outage. On the other hand, during the backwashing process, the water flowing downward in the third water pipe generates negative pressure at a position near the third water pipe in the inner cavity of the fifth water pipe. The negative pressure in the fifth water pipe causes the air in the fourth water pipe to continuously enter the fifth water pipe, and the liquid level of the water in the fourth water pipe continuously rises, causing the water in the fourth water pipe to generate a siphon, thereby increasing the hydraulic pressure difference between the inside and outside of the tubular filter element being backwashed, thereby improving the backwashing effect. In addition, the tap water secondary purification device has a simple structure and is easy to maintain.

[0020] 2. In the tap water secondary purification device of the example of the present invention, on the one hand, during the backwashing process, the water in the tubular filter element undergoing backwashing flows upward, and the upward-flowing water drives the spiral blades to rotate, and the edge of the spiral blades and the inner wall of the tubular filter element slide relative to each other, thereby causing impurities on the inner wall of the tubular filter element to fall off, thereby improving the cleaning effect of the backwashing of the tubular filter element; on the other hand, the rotating spiral blades reduce the hydraulic pressure at the bottom of the inner cavity of the tubular filter element, and the water at the top of the inner cavity of the tubular filter element is sprayed out through the first through hole, the cavity of the rotating shaft, and the second through hole. The water sprayed out from the second through hole washes the impurities on the bottom side of the inner cavity of the tubular filter element, thereby reducing the residual impurities in the inner cavity of the tubular filter element.

[0021] 3. In the tap water secondary purification device of the example of the present invention, when the sixth water pipe does not block the opening, the external air enters the fourth water pipe through the opening valve, so that the liquid level of the water in the fourth water pipe is flush with the liquid level of the water in the water pool, thereby reducing the tap water in the raw water cavity from flowing out through the gap between the sixth water pipe and the partition, thereby reducing the loss of tap water.

[0022] 4. In the tap water secondary purification device of the example of the present invention, when the first water pipe drives the sixth water pipe to rotate, the friction between the edge of the rotating ring and the inner wall of the shell causes the rotating ring to drive the brush to rotate, and the rotating brush sweeps away impurities on the moving path of the sixth water pipe to prevent the impurities from hindering the movement of the sixth water pipe. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the main structure of the present invention; Figure 2 It is a schematic diagram of the backwashing state of the present invention; Figure 3 for Figure 2 A schematic diagram of the structure at A; Figure 4 for Figure 2 A schematic diagram of the structure at B; Figure 5 It is a schematic diagram of the water purification state structure of the present invention; Figure 6 It is a partial cross-sectional structural schematic diagram of the tubular filter element of the present invention; Figure 7 It is a schematic diagram of a partial cross-sectional structure of the sixth water pipe of the present invention.

[0024] In the figure: 1 shell, 2 water outlet, 3 water inlet, 4 limit mechanism, 41 slide bar, 42 fixed block, 43 elastic member, 44 grip bar, 45 chuck, 5 first water pipe, 6 second water pipe, 7 third water pipe, 8 fourth water pipe, 9 fifth water pipe, 10 tubular filter element, 11 partition, 12 sixth water pipe, 13 opening valve, 14 rotating shaft, 15 spiral blade, 16 pool, 17 brush, 18 rotating ring, 19 first through hole, 20 second through hole. DETAILED DESCRIPTION

[0025] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0026] Embodiment 1: See also Figure 1-5The present embodiment discloses a tap water secondary purification device, comprising a shell 1 with a hollow interior and a partition 11 located in the inner cavity of the shell 1, a mounting hole is provided in the middle of the top side of the shell 1, a first water pipe 5 is installed in the mounting hole through a sealing bearing, the inner wall of the shell 1 and the edge of the partition 11 are fixedly sealed and connected, the partition 11 divides the inner cavity of the shell 1 into a raw water cavity and a clean water cavity, and the raw water cavity is located above the clean water cavity, a water inlet 3 connected to the raw water cavity is provided on the shell 1, a water outlet 2 connected to the clean water cavity is provided on the shell 1, a plurality of openings are provided at equal angles around the first water pipe 5 on the partition 11, a tubular filter element 10 is penetrated in each opening, the outer peripheral side of the tubular filter element 10 and the inner wall of the opening are slidingly sealed and fitted, the bottom end of the tubular filter element 10 and the bottom side of the inner cavity of the shell 1 are connected by a buckle or a threaded pin, the height of the top end of the tubular filter element 10 is less than the height of the top side of the partition 11, and the height of the top end of the tubular filter element 10 is greater than the height of the bottom side of the partition 11.

[0027] A plurality of sixth water pipes 12 are arranged around the bottom end of the first water pipe 5 , and the number of the sixth water pipes 12 is less than the number of the openings. The bottom end of the first water pipe 5 is connected to one end of the sixth water pipe 12 , and the other end of the sixth water pipe 12 is slidably fitted to the top side of the partition 11 .

[0028] Furthermore, when the number of the sixth water pipes 12 is not less than two, the interval angle between any two sixth water pipes 12 around the first water pipe 5 is an integer multiple of the interval angle between two adjacent openings around the first water pipe 5 .

[0029] The working process and principle of this embodiment are: The water inlet 3 of the shell 1 is connected to an external tap water pipe, and the external tap water pipe supplies water to the raw water cavity of the shell 1 through the water inlet 3. The water outlet 2 on the shell 1 is connected to the external water supply pipe, and the purified water in the clean water cavity of the shell 1 enters the external water supply pipe through the water outlet 2.

[0030] The tap water in the raw water cavity enters the inner cavity of the tubular filter element 10, the hydraulic pressure inside the tubular filter element 10 is higher than the hydraulic pressure outside the tubular filter element 10, and the tap water in the tubular filter element 10 flows through the tubular filter element 10 to the clean water cavity of the shell 1, thereby achieving purification and filtration of the tap water.

[0031] The staff monitors the water pressure in the clean water chamber and the water pressure in the raw water chamber through the hydraulic measuring equipment. When the staff monitors that the difference between the water pressure in the raw water chamber and the water pressure in the clean water chamber exceeds the set value, the staff rotates the first water pipe 5 to a set angle, and the first water pipe 5 drives the sixth water pipe 12 to rotate. The staff makes each sixth water pipe 12 cover an opening, and some openings are not blocked by the sixth water pipe 12. The water in the clean water chamber is discharged through the tubular filter element 10 below the sixth water pipe 12, the opening below the sixth water pipe 12, the sixth water pipe 12, and the first water pipe 5. The water flow at the tubular filter element 10 below the sixth water pipe 12 flows from outside to inside, realizing backwashing of the tubular filter element 10. At this time, only part of the tubular filter element 10 is backwashed. Then the staff rotates the first water pipe 5 to a set angle, and the first water pipe 5 drives the sixth water pipe 12 to rotate, so that the rotating sixth water pipe 12 completely covers the openings at other positions, realizing backwashing of the tubular filter element 10 that has not been backwashed.

[0032] After the backwashing of the tubular filter element 10 in the housing 1 is completed, the staff rotates the first water pipe 5 to a set angle, and the first water pipe 5 drives the sixth water pipe 12 to rotate, and the sixth water pipe 12 is separated from the opening. Figure 5 As shown, the present tap water secondary purification device can realize backwashing of the tubular filter element 10 without stopping the water supply, thereby ensuring the stability and continuity of the tap water supply and reducing the inconvenience or loss caused by water outage.

[0033] Embodiment 2: like Figure 1 , 2 As shown in Figures 4 and 5, this embodiment discloses a tap water secondary purification device, and its structure is substantially the same as that of the first embodiment, except that this embodiment further includes a second water pipe 6 and a water pool 16, the second water pipe 6 has a first end and a second end, and the first end of the second water pipe 6 is higher than the second end of the second water pipe 6, the second end of the second water pipe 6 and the top end of the first water pipe 5 are connected by a rotating joint, the first end of the second water pipe 6 is connected to the top end of the fourth water pipe 8, the inner cavity of the second water pipe 6 is connected to the top end of the third water pipe 7, the third water pipe 7 is located between the first water pipe 5 and the fourth water pipe 8, the inner cavity cross-section of the third water pipe 7 is smaller than the inner cavity cross-section of the second water pipe 6, the top of the inner cavity of the second water pipe 6 near the first end of the second water pipe 6 is connected to one end of the fifth water pipe 9, the other end of the fifth water pipe 9 is connected to the middle of the inner cavity of the third water pipe 7, and the bottom ends of the third water pipe 7 and the fourth water pipe 8 both extend into the inner cavity of the water pool 16.

[0034] Furthermore, the ratio of the inner cavity cross section of the third water pipe 7 to the inner cavity cross section of the second water pipe 6 is 1.0:10.0-50.0.

[0035] The working process and principle of this embodiment are: During the backwashing process, the water in the first water pipe 5 continuously flows into the second water pipe 6, the water in the second water pipe 6 first flows into the third water pipe 7, and the water in the third water pipe 7 flows into the pool 16, the water in the pool 16 submerges the bottom ends of the third water pipe 7 and the bottom ends of the fourth water pipe 8, the water flowing downward in the third water pipe 7 causes a negative pressure to be generated in the inner cavity of the fifth water pipe 9 near the position of the third water pipe 7, the negative pressure in the fifth water pipe 9 causes the air in the fourth water pipe 8 to continuously enter the fifth water pipe 9, the liquid level of the water in the fourth water pipe 8 continuously rises, causing the water in the fourth water pipe 8 to generate a siphon, thereby increasing the hydraulic pressure difference between the inside and outside of the tubular filter element 10 that is backwashing, thereby improving the backwashing effect, and the present tap water secondary purification device has a simple structure and is easy to maintain.

[0036] Preferably, the top side of the pool 16 is lower than the bottom side of the housing 1 .

[0037] Embodiment three: like Figure 6 As shown, this embodiment discloses a tap water secondary purification device, and its structure is roughly the same as that of the second embodiment, except that a rotating shaft 14 is coaxially installed in the inner cavity of the tubular filter element 10 of this embodiment through a bearing or a rotating pin, and a spiral blade 15 is installed on the rotating shaft 14, and the edge of the spiral blade 15 is slidably fitted with the inner wall of the tubular filter element 10.

[0038] The working process and principle of this embodiment are: During the backwashing process, water in the tubular filter element 10 undergoing backwashing flows upward, and the upward flowing water drives the spiral blades 15 to rotate. The edges of the spiral blades 15 and the inner wall of the tubular filter element 10 slide relative to each other, causing impurities on the inner wall of the tubular filter element 10 to fall off, thereby improving the cleaning effect of the backwashing of the tubular filter element 10.

[0039] Embodiment 4: like Figure 6 As shown, this embodiment discloses a tap water secondary purification device, and its structure is substantially the same as that of the third embodiment, except that a cavity is provided inside the rotating shaft 14 of this embodiment, a first through hole 19 connected to the cavity is provided at the top end of the rotating shaft 14, and a second through hole 20 connected to the cavity is provided at the bottom end of the rotating shaft 14.

[0040] The working process and principle of this embodiment are: During the backwashing process, the water in the tubular filter element 10 undergoing backwashing flows upward, and the upward flowing water drives the spiral blades 15 to rotate. The rotating spiral blades 15 reduce the hydraulic pressure at the bottom of the inner cavity of the tubular filter element 10, and the hydraulic pressure at the second through hole 20 is less than the hydraulic pressure at the first through hole 19. The water at the top of the inner cavity of the tubular filter element 10 is sprayed out through the first through hole 19, the cavity of the rotating shaft 14, and the second through hole 20. The water sprayed from the second through hole 20 washes the impurities on the bottom side of the inner cavity of the tubular filter element 10, thereby reducing the residual impurities in the inner cavity of the tubular filter element 10.

[0041] Embodiment five: like Figure 6 As shown, this embodiment discloses a tap water secondary purification device, whose structure is roughly the same as that of the third embodiment, except that the spiral blades 15 of this embodiment are made of elastic rubber or elastic plastic material, which reduces the damage to the inner wall of the tubular filter element 10 during the rotation of the spiral blades 15.

[0042] Embodiment six: like Figure 1 , 2 As shown in Figures 4 and 5, this embodiment discloses a tap water secondary purification device, and its structure is substantially the same as that of the second embodiment, except that, in this embodiment, an opening valve 13 connected to the inner cavity of the second water pipe 6 is installed at the top of the outer side of the second water pipe 6 near the first end of the second water pipe 6. The staff adjusts the opening of the opening valve 13 so that the ratio of the valve cross-sectional area of ​​the opening valve 13 to the cross-sectional area of ​​the inner cavity of the third water pipe 7 is 1.0:30.0-100.0.

[0043] Furthermore, in the prior art, the opening degree of the opening valve 13 has a direct impact on the flow rate and pressure drop of the fluid. When the opening degree of the opening valve 13 changes, the valve cross-sectional area will also change accordingly. The valve cross-sectional area is also called the effective cross-sectional area, which refers to the effective flow area when the fluid flows through the valve.

[0044] Furthermore, the inner cavity cross-section of the third water pipe 7 refers to the effective flow area when the fluid flows through the third water pipe 7 .

[0045] The working process and principle of this embodiment are: When the sixth water pipe 12 does not block the opening, external air enters the fourth water pipe 8 through the opening valve 13, interrupting the siphon, making the liquid level of the water in the fourth water pipe 8 flush with the liquid level of the water in the water pool 16, reducing the outflow of tap water in the raw water cavity through the gap between the sixth water pipe 12 and the partition 11, and reducing the loss of tap water.

[0046] During the backwashing process, the air entering the fourth water pipe 8 through the opening valve 13 is continuously sucked away by the fifth water pipe 9 , and the opening valve 13 does not affect the siphoning of the water in the fourth water pipe 8 .

[0047] Embodiment seven: like Figure 2 , 3As shown, the present embodiment discloses a tap water secondary purification device, and its structure is substantially the same as that of the first embodiment, except that a limiting mechanism 4 is installed on the top side of the shell 1 of the present embodiment, and the limiting mechanism 4 includes a chuck 45 coaxially fixed on the first water pipe 5 and a fixed block 42 fixed on the top side of the shell 1, and a sliding hole is opened on the fixed block 42, and a sliding rod 41 is slidably penetrated in the sliding hole, and one end of the sliding rod 41 is pressed against the edge of the chuck 45, and an elastic member 43 for pushing the sliding rod 41 to move toward the chuck 45 is installed on the fixed block 42, and the elastic member 43 is a spring or an elastic rod.

[0048] The working process and principle of this embodiment are: After the staff rotates the first water pipe 5 , the friction between the slide bar 41 and the chuck 45 fixes the position of the first water pipe 5 , thereby ensuring that the position of the sixth water pipe 12 in the inner cavity of the shell 1 is fixed.

[0049] Furthermore, the chuck 45 is fixedly connected to one end of the gripping rod 44 , and the gripping rod 44 facilitates the staff to rotate the first water pipe 5 through the chuck 45 .

[0050] Embodiment eight: like Figure 3 As shown, this embodiment discloses a tap water secondary purification device, and its structure is substantially the same as that of the seventh embodiment, except that a plurality of slots are provided at equal angles along the edge of the chuck 45 of this embodiment.

[0051] Furthermore, the spacing angle between two adjacent slots around the first water pipe 5 is twice the spacing angle between two adjacent openings around the first water pipe 5 .

[0052] The working process and principle of this embodiment are: The clamping groove on the clamping disc 45 improves the accuracy of the rotation angle of the first water pipe 5, thereby improving the reliability and operation convenience of the tap water secondary purification device.

[0053] Embodiment nine: like Figure 7 As shown, this embodiment discloses a tap water secondary purification device, and its structure is roughly the same as that of the first embodiment, except that, in this embodiment, a rotating ring 18 is installed at a position of the sixth water pipe 12 away from the first water pipe 5, and a brush 17 is fixed to the bottom side of the ring 18, the brush 17 abuts against the top side of the partition 11, and the edge of the ring 18 abuts against the inner wall of the shell 1.

[0054] The working process and principle of this embodiment are: When the first water pipe 5 drives the sixth water pipe 12 to rotate, the friction between the edge of the swivel 18 and the inner wall of the shell 1 causes the swivel 18 to drive the brush 17 to rotate. The rotating brush 17 sweeps away impurities on the moving path of the sixth water pipe 12 to prevent the impurities from hindering the movement of the sixth water pipe 12.

[0055] Furthermore, an elastic rubber ring is fixed to a position of the sixth water pipe 12 away from the first water pipe 5 , and the elastic rubber ring enhances the sealing fit between the sixth water pipe 12 and the partition 11 .

[0056] While the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that many changes, modifications, substitutions and variations can be made to the embodiments without departing from the principles and spirit of the invention.

Claims

1. A tap water secondary purification device, characterized in that: The invention comprises a shell (1) with a hollow interior and a partition (11) located in the inner cavity of the shell (1); a mounting hole is provided in the middle of the top side of the shell (1); a rotatable first water pipe (5) is installed in the mounting hole; the inner wall of the shell (1) and the edge of the partition (11) are fixedly sealed and connected; the partition (11) divides the inner cavity of the shell (1) into a raw water cavity and a clean water cavity, and the raw water cavity is located above the clean water cavity; the shell (1) is provided with an inlet port connected to the raw water cavity. A water inlet (3), wherein the shell (1) is provided with a water outlet (2) connected to the clean water cavity, and the partition (11) is provided with a plurality of openings at equal angles around the first water pipe (5), each opening having a tubular filter element (10) inserted therein, the outer peripheral side of the tubular filter element (10) and the inner wall of the opening being slidingly and sealingly fitted, the bottom end of the tubular filter element (10) and the bottom side of the inner cavity of the shell (1) being detachably connected, and the top end of the tubular filter element (10) being lower than the top side of the partition (11); A plurality of sixth water pipes (12) are arranged around the bottom end of the first water pipe (5), and the number of the sixth water pipes (12) is less than the number of the openings; the bottom end of the first water pipe (5) is connected to one end of the sixth water pipe (12), and the other end of the sixth water pipe (12) is slidably fitted to the top side of the partition (11); Wherein, when the number of the sixth water pipes (12) is not less than two, the spacing angle between any two sixth water pipes (12) around the first water pipe (5) is an integer multiple of the spacing angle between two adjacent openings around the first water pipe (5); The backwashing operation includes rotating the first water pipe (5) so that the sixth water pipe (12) completely covers the opening; The recovery operation after backwashing is as follows: the first water pipe (5) is rotated to separate the sixth water pipe (12) from the opening.

2. The tap water secondary purification device according to claim 1, characterized in that: It also comprises a second water pipe (6) and a pool (16), wherein the second water pipe (6) has a first end and a second end, and the first end of the second water pipe (6) is higher than the second end of the second water pipe (6), the second end of the second water pipe (6) is connected to the top end of the first water pipe (5) via a rotating joint, the first end of the second water pipe (6) is connected to the top end of the fourth water pipe (8), the inner cavity of the second water pipe (6) is connected to the top end of the third water pipe (7), the third water pipe (7) is located between the first water pipe (5) and the fourth water pipe (8), the top of the inner cavity of the second water pipe (6) near the first end of the second water pipe (6) is connected to one end of the fifth water pipe (9), the other end of the fifth water pipe (9) is connected to the middle of the inner cavity of the third water pipe (7), and the bottom ends of the third water pipe (7) and the fourth water pipe (8) both extend into the inner cavity of the pool (16).

3. The tap water secondary purification device according to claim 2, characterized in that: A rotating shaft (14) is coaxially mounted in the inner cavity of the tubular filter element (10), a spiral blade (15) is mounted on the rotating shaft (14), and the edge of the spiral blade (15) is slidably fitted to the inner wall of the tubular filter element (10).

4. The tap water secondary purification device according to claim 3, characterized in that: A cavity is provided inside the rotating shaft (14); a first through hole (19) communicating with the cavity is provided at the top end of the rotating shaft (14); and a second through hole (20) communicating with the cavity is provided at the bottom end of the rotating shaft (14).

5. The tap water secondary purification device according to claim 3, characterized in that: The spiral blade (15) is made of elastic rubber material or elastic plastic material.

6. The tap water secondary purification device according to claim 2, characterized in that: An opening valve (13) connected to the inner cavity of the second water pipe (6) is installed at a position on the outer top of the second water pipe (6) near the first end of the second water pipe (6), and the ratio of the valve cross-sectional area of ​​the opening valve (13) to the inner cavity cross-sectional area of ​​the third water pipe (7) is 1.0:30.0-100.

0.

7. The tap water secondary purification device according to claim 1, characterized in that: A limiting mechanism (4) is installed on the top side of the shell (1), and the limiting mechanism (4) comprises a chuck (45) coaxially fixed on the first water pipe (5) and a fixed block (42) fixed on the top side of the shell (1), a sliding rod (41) is installed on the fixed block (42), one end of the sliding rod (41) is pressed against the edge of the chuck (45), and an elastic member (43) is installed on the fixed block (42) for pushing the sliding rod (41) to move toward the chuck (45).

8. The tap water secondary purification device according to claim 7, characterized in that: The edge of the chuck (45) is provided with a plurality of equiangular slots.

9. The tap water secondary purification device according to claim 7, characterized in that: The chuck (45) is fixedly connected to one end of the gripping rod (44).

10. The tap water secondary purification device according to claim 1, characterized in that: A rotating ring (18) is installed at a position of the sixth water pipe (12) away from the first water pipe (5); a brush (17) is fixed to the bottom side of the rotating ring (18); the brush (17) abuts against the top side of the partition (11); and the edge of the rotating ring (18) abuts against the inner wall of the shell (1).

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