A multi-media filter for tap water treatment and filtration

Abstract

The present invention discloses a multi-media filter for tap water treatment and filtration, comprising a first filter box, a second filter box, and a third filter box, wherein the first filter box, the second filter box, and the third filter box are arranged in sequence from bottom to top, and a partition is fixedly connected between the first filter box and the second filter box, and between the second filter box and the third filter box, the top of the third filter box is connected to a water inlet pipe, and the bottom of the first filter box is connected to a water outlet pipe. The beneficial effect of the present invention is that the present invention filters tap water by squeezing by providing three filter boxes, and three filter pushing mechanisms made of different materials are respectively provided in the filter boxes, and the three filter pushing mechanisms are asynchronously driven by three transmission mechanisms, thereby realizing asynchronous filtration of different filter boxes, and the transmission mechanism cooperates with the valve assembly to continuously circulate and filter, thereby solving the problems of slow filtration efficiency and high energy consumption of traditional tap water filtration equipment.

Description

Technical Field

[0001] The invention relates to the technical field of tap water filtration, in particular to a multi-media filter for tap water treatment and filtration. Background Art

[0002] Tap water refers to water that meets the relevant standards and is produced after purification and disinfection at a water treatment plant for people's daily life and production. Domestic water is mainly drawn from rivers, lakes, groundwater, and surface water through the water plant's water intake pump station. After being processed through processes such as sedimentation, disinfection, and filtration, it is finally delivered to various users through a water distribution pump station. When tap water is treated at a water plant, the last step usually requires filtering the groundwater or surface water. Traditional tap water filtration usually involves passing water through a multi-stage filter for osmosis or reverse osmosis filtration. The water flows continuously and is transmitted by the power of the water pump. Since the multi-stage filter layers are mostly stacked in sequence, during the continuous filtration process, as impurities accumulate, the flowable gaps in the multi-stage filter layers become smaller and smaller, the water flow and filtration rate becomes slower and slower, and energy consumption gradually increases. In the later stage, the filter element can only be replaced, which is costly. Summary of the Invention

[0003] The object of the present invention is to provide a multi-media filter for tap water treatment and filtration to solve the problems raised in the above background technology.

[0004] To achieve the above-mentioned object, the present invention provides the following technical solution: a multi-media filter for tap water treatment and filtration, comprising a first filter box, a second filter box and a third filter box, wherein the first filter box, the second filter box and the third filter box are arranged in sequence from bottom to top, a partition is fixedly connected between the first filter box and the second filter box and between the second filter box and the third filter box, the top of the third filter box is connected to an inlet pipe, the bottom of the first filter box is connected to an outlet pipe, a bottom plate is fixedly connected to the bottom of one side of the first filter box, a top plate is fixedly connected to the top of one side of the third filter box, the bottom plate and A double-plate mounting frame is fixedly connected between the top plates and at one end away from the first filter box, and three transmission mechanisms are equidistantly provided on the outside of the double-plate mounting frame. Push filter mechanisms are provided inside the first filter box, the second filter box and the third filter box, and the transmission mechanism is used to drive the push filter mechanism. A servo motor is fixedly installed on the top of the bottom plate and at one end away from the first filter box, and the servo motor is connected to one of the transmission mechanisms for driving the transmission mechanism. A valve assembly is provided on the side of the partition close to the double-plate mounting frame for controlling the communication between the first filter box, the second filter box and the third filter box.

[0005] Preferably, the transmission mechanism includes three first and second turntables equidistantly arranged on the outside of the double-plate mounting frame, the first and second turntables are fixedly connected by a rotating shaft, and the rotating shaft is rotatably connected to the double-plate mounting frame, the outer edge of the first turntable is fixedly connected to a fixed rotating rod, the end of the fixed rotating rod away from the first turntable is rotatably connected to the first connecting rod, the side of the second turntable away from the first turntable is eccentrically connected to the second connecting rod, and the second connecting rod is eccentrically connected to the outer side of the adjacent second turntable.

[0006] Preferably, the end of the output shaft of the servo motor is fixedly connected to a driving pulley, and a driven pulley is installed on the outer side of the rotating shaft in the transmission mechanism on one side of the first filter box, and the servo motor is connected to the transmission mechanism through a belt.

[0007] Preferably, the filter pushing mechanism includes a filter plate, and the interiors of the first filter box, the second filter box and the third filter box are all slidably connected with filter plates, and the three filter plates are fixedly connected to one end of the double-plate mounting frame with two sliding rods, and the end of the sliding rod away from the filter plate extends to the outside of the first filter box, the second filter box or the third filter box and is fixedly connected with a push plate, and the side of the push plate away from the sliding rod is rotatably connected to the end of the first connecting rod.

[0008] Preferably, the three filter plates are filled with activated carbon particles, quartz sand particles and cotton fibers in sequence from top to bottom.

[0009] Preferably, the valve assembly includes a drain hole, and the two partitions are provided with a drain hole at one end close to the double-plate mounting frame, and the interiors of the first filter box, the second filter box and the third filter box are all connected to the drain hole, and a sieve plate is slidably connected to the interior of the partition and at one end close to the double-plate mounting frame at the drain hole, and a circular slider is fixedly connected to the outside of the sieve plate and located on the outside of the partition, and the bottom of one side of the second filter box and the third filter box are fixedly connected to a mounting seat, and one side of the mounting seat is rotatably connected to a rotating plate through a torsion spring, and a sliding groove is provided at the bottom of the rotating plate, and the circular slider is slidably connected to the sliding groove.

[0010] Preferably, a first micro switch is fixedly installed at the bottom of the top plate and at one end away from the third filter box, and a second micro switch is fixedly installed at the top of the bottom plate and at one end close to the first filter box. Solenoid valves are installed on the outside of the water inlet pipe and the water outlet pipe. The first micro switch is electrically connected to the solenoid valve on the outside of the water inlet pipe, and the second micro switch is electrically connected to the solenoid valve on the outside of the water outlet pipe.

[0011] Preferably, the middle parts of the first filter box, the second filter box and the third filter box away from the double plate mounting frame are all connected to a backwash port, and the bottom parts of the first filter box, the second filter box and the third filter box away from the double plate mounting frame are all connected to a backwash drain port.

[0012] Compared with the prior art, the beneficial effects of the present invention are as follows: the present invention is provided with three filter boxes, and three filter pushing mechanisms made of different materials are respectively provided in the filter boxes, and the tap water is filtered by squeezing, thereby achieving the effect of high-efficiency multi-media filtration, and the three filter pushing mechanisms are asynchronously driven by three transmission mechanisms, thereby achieving asynchronous filtration of different filter boxes, and the transmission mechanism is coordinated with the valve assembly to make the filter box automatically lower the tap water after filtering the tap water, so that the tap water automatically flows into the next filter box, and then continuously circulates and filters, thereby solving the problems of slow filtration efficiency and high energy consumption of traditional tap water filtration equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a structural schematic diagram of the present invention;

[0014] Figure 2 It is a working schematic diagram of the present invention;

[0015] Figure 3 Schematic diagram of the installation of the transmission mechanism of the present invention;

[0016] Figure 4 For the present invention Figure 2 A magnified view of point A in the figure;

[0017] Figure 5 Schematic diagram of triggering the first micro switch of the present invention.

[0018] In the figure: 1. First filter box; 2. Second filter box; 3. Third filter box; 4. Partition; 5. Water inlet pipe; 6. Water outlet pipe; 7. Bottom plate; 8. Top plate; 9. Double-plate mounting bracket; 10. Transmission mechanism; 101. First turntable; 102. Second turntable; 103. Fixed rotating rod; 104. First connecting rod; 105. Second connecting rod; 11. Filter pushing mechanism; 111. Filter plate; 112. Sliding rod; 113. Push plate; 12. Servo motor; 13. Valve assembly; 131. Drain hole; 132. Sieve plate; 133. Sliding block; 134. Mounting seat; 135. Rotating plate; 136. Slide; 14. First micro switch; 15. Second micro switch; 16. Backflush port; 17. Backflush emptying port. DETAILED DESCRIPTION

[0019] In the description of this application, it should be noted that the terms "upper", "lower", "inside", "outside", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, or are the orientations or positional relationships in which the product of the application is usually placed when in use. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they should not be understood as limitations on this application.

[0020] It should also be noted that, in the description of this application, unless otherwise expressly specified or limited, the terms "disposed" and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; mechanical connections, or electrical connections; direct connections, indirect connections through an intermediate medium, or internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on the specific circumstances.

[0021] The following describes some embodiments of the present application in detail with reference to the accompanying drawings. In the absence of conflict, the following embodiments and the features therein can be mutually applicable.

[0022] See also Figure 1-5 , a multi-media filter for tap water treatment and filtration, comprising a first filter box 1, a second filter box 2 and a third filter box 3, the first filter box 1, the second filter box 2 and the third filter box 3 are arranged in sequence from bottom to top, a partition 4 is fixedly connected between the first filter box 1 and the second filter box 2 and between the second filter box 2 and the third filter box 3, the top of the third filter box 3 is connected to a water inlet pipe 5, the bottom of the first filter box 1 is connected to a water outlet pipe 6, a bottom plate 7 is fixedly connected to the bottom of one side of the first filter box 1, a top plate 8 is fixedly connected to the top of one side of the third filter box 3, and an end between the bottom plate 7 and the top plate 8 and away from the first filter box 1 A double-plate mounting frame 9 is fixedly connected, and three transmission mechanisms 10 are equidistantly provided on the outside of the double-plate mounting frame 9. A filter pushing mechanism 11 is provided inside the first filter box 1, the second filter box 2 and the third filter box 3. The transmission mechanism 10 is used to drive the filter pushing mechanism 11. A servo motor 12 is fixedly installed on the top of the bottom plate 7 and at one end away from the first filter box 1. The servo motor 12 is connected to one of the transmission mechanisms 10 for driving the transmission mechanism 10. A valve assembly 13 is provided on the side of the partition 4 close to the double-plate mounting frame 9 for controlling the communication between the first filter box 1, the second filter box 2 and the third filter box 3.

[0023] Specifically, the present invention sets up three filter boxes, and three filter pushing mechanisms 11 made of different materials are respectively provided in the filter boxes. The tap water is filtered by squeezing, thereby achieving the effect of high-efficiency multi-media filtration. The three filter pushing mechanisms 11 are asynchronously driven by three transmission mechanisms 10, thereby achieving asynchronous filtration of different filter boxes. The transmission mechanism 10 cooperates with the valve assembly 13 to make the filter box automatically lower the tap water after filtering the tap water, so that the tap water automatically flows into the next filter box, and then continuously circulates and filters, thereby solving the problems of slow filtration efficiency and high energy consumption of traditional tap water filtration equipment.

[0024] Furthermore, the transmission mechanism 10 includes three first turntables 101 and second turntables 102 equidistantly arranged on the outside of the double-plate mounting frame 9, the first turntable 101 and the second turntable 102 are fixedly connected by a rotating shaft, and the rotating shaft is rotatably connected to the double-plate mounting frame 9, the outer edge of the first turntable 101 is fixedly connected to a fixed rotating rod 103, the end of the fixed rotating rod 103 away from the first turntable 101 is rotatably connected to a first connecting rod 104, the side of the second turntable 102 away from the first turntable 101 is eccentrically connected to a second connecting rod 105, the second connecting rod 105 is eccentrically connected to the outside of the adjacent second turntable 102, the output shaft end of the servo motor 12 is fixedly connected to a driving pulley, and a driven pulley is installed on the outside of the rotating shaft in the transmission mechanism 10 on the side of the first filter box 1, and the servo motor 12 is connected to the transmission mechanism 10 through a belt.

[0025] Specifically, when the servo motor 12 drives the bottom first turntable 101 and the second turntable 102 to rotate through the belt, the second turntable 102 causes all the second turntables 102 above to rotate synchronously through the second connecting rod 105. At the same time, the second turntable 102 drives the first turntable 101 to rotate through the rotating shaft. When the three first turntables 101 rotate, they push the three filter pushing mechanisms 11 to slide back and forth left and right through the fixed rotating rod 103 and the first connecting rod 104 to filter the tap water.

[0026] Furthermore, the filter pushing mechanism 11 includes a filter plate 111, and the interiors of the first filter box 1, the second filter box 2 and the third filter box 3 are all slidably connected with filter plates 111, and the three filter plates 111 are fixedly connected with two slide rods 112 at one end close to the double-plate mounting frame 9, and the slide rods 112 extend to the outside of the first filter box 1, the second filter box 2 or the third filter box 3 at one end away from the filter plate 111 and are fixedly connected with a push plate 113, and the push plate 113 is rotatably connected to the end of the first connecting rod 104 on the side away from the slide rod 112, and the three filter plates 111 are filled with activated carbon particles, quartz sand particles and cotton fibers from top to bottom.

[0027] Specifically, when the transmission mechanism 10 pushes the three push plates 113 to move back and forth, the three push plates 113 push the filter plates 111 in the first filter box 1, the second filter box 2 or the third filter box 3 to slide left and right through the sliding rod 112. When the filter plate 111 slides to the right, the water is filtered. When the water is drained, the filter plate 111 slides to the left and waits for the next box of tap water to enter the filter box.

[0028] Furthermore, the valve assembly 13 includes a drain hole 131, and the two partitions 4 are provided with a drain hole 131 at one end close to the double-plate mounting frame 9, and the interiors of the first filter box 1, the second filter box 2 and the third filter box 3 are all connected to the drain hole 131. The interior of the partition 4 and the end located at the drain hole 131 close to the double-plate mounting frame 9 are slidably connected with a sieve plate 132, and the outside of the sieve plate 132 and the outside of the partition 4 are fixedly connected with a circular slider 133, and the bottom of one side of the second filter box 2 and the third filter box 3 are fixedly connected with a mounting seat 134, and one side of the mounting seat 134 is rotatably connected to a rotating plate 135 through a torsion spring, and a slide groove 136 is provided at the bottom of the rotating plate 135, and the circular slider 133 is slidably connected to the slide groove 136.

[0029] Specifically, when the two upper push plates 113 slide to the right, the filter plate 111 slides to the right to filter the water. When the push plate 113 is close to the second filter box 2 or the third filter box 3, the push plate 113 squeezes the top of the rotating plate 135 to make it rotate clockwise. The rotating plate 135 rotates through the chute 136 and the round slider 133 to pull the sieve plate 132 to slide to the left. After the sieve plate 132 slides to the left, the two lower filter boxes are connected through the drain hole 131, and the water flows downward. After the water flows out, the push plate 113 slides to the right, and the rotating plate 135 is reset by the torsion spring to block the drain hole 131. At this time, the filter box waits for the water in the water inlet pipe 5 or the previous filter box to flow in, and then the cycle continues.

[0030] Furthermore, a first micro switch 14 is fixedly installed at the bottom of the top plate 8 and at one end away from the third filter box 3, and a second micro switch 15 is fixedly installed at the top of the bottom plate 7 and at one end close to the first filter box 1. Solenoid valves are installed on the outside of the water inlet pipe 5 and the water outlet pipe 6. The first micro switch 14 is electrically connected to the solenoid valve on the outside of the water inlet pipe 5, and the second micro switch 15 is electrically connected to the solenoid valve on the outside of the water outlet pipe 6.

[0031] Specifically, when the top push plate 113 slides to the leftmost side, it touches the first microswitch 14, thereby opening the solenoid valve of the water inlet pipe 5, and the tap water flows into the third filter box 3 through the water inlet pipe 5. After releasing, the solenoid valve of the water inlet pipe 5 is closed. Similarly, when the bottom push plate 113 slides to the rightmost side, it touches the second microswitch 15, thereby opening the solenoid valve of the water outlet pipe 6, and the tap water in the first filter box 1 flows out through the water outlet pipe 6.

[0032] Furthermore, the middle parts of the first filter box 1, the second filter box 2 and the third filter box 3 on the side away from the double-plate mounting frame 9 are all connected to a backwash port 16, and the bottom parts of the first filter box 1, the second filter box 2 and the third filter box 3 on the side away from the double-plate mounting frame 9 are all connected to a backwash drain port 17, so as to better backwash the filter plates 111 in the first filter box 1, the second filter box 2 and the third filter box 3.

[0033] Specifically, such as Figure 2 As shown, the servo motor 12 is turned on. When the servo motor 12 drives the bottom first turntable 101 and the second turntable 102 to rotate through the belt, the second turntable 102 causes all the second turntables 102 above to rotate synchronously through the second connecting rod 105. At the same time, the second turntable 102 drives the first turntable 101 to rotate through the rotating shaft. When the three first turntables 101 rotate, they push the three filter pushing mechanisms 11 to slide back and forth left and right through the fixed rotating rod 103 and the first connecting rod 104 to filter the tap water. When the filter plate 111 slides to the right, the water is filtered. When the water is drained, the filter plate 111 slides to the left to wait for the next box of tap water to enter the filter box; when the two push plates 113 above slide to the right, the filter plate 111 slides to the right to filter the water. When the push plate 113 is close to the second filter box 2 or the third filter box 3, the push plate 113 squeezes the top of the rotating plate 135 to make it rotate clockwise, and the rotating plate When the sieve plate 132 slides to the left, the sieve plate 132 is pulled to slide through the chute 136 and the round slider 133. After the sieve plate 132 slides to the left, the two filter boxes are connected through the water outlet 131, and the water flows downward. After the water flows out, the push plate 113 slides to the right, and the rotating plate 135 is reset by the torsion spring to block the water outlet 131. At this time, the filter box waits for the water in the water inlet pipe 5 or the previous filter box to flow in, and then circulates continuously. At the same time, when the uppermost push plate 113 slides to the left to the extreme left, the first microswitch 14 is triggered, thereby opening the solenoid valve of the water inlet pipe 5, and the tap water flows into the third filter box 3 through the water inlet pipe 5. After being released, the solenoid valve of the water inlet pipe 5 is closed. Similarly, when the lower push plate 113 slides to the right to the extreme right, the second microswitch 15 is triggered, thereby opening the solenoid valve of the water outlet pipe 6, and the tap water in the first filter box 1 flows out through the water outlet pipe 6, and circulates continuously to continuously filter the tap water.

[0034] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A multi-media filter for tap water treatment and filtration, comprising a first filter box (1), a second filter box (2) and a third filter box (3), characterized in that: The first filter box (1), the second filter box (2) and the third filter box (3) are arranged in sequence from bottom to top; a partition plate (4) is fixedly connected between the first filter box (1) and the second filter box (2) and between the second filter box (2) and the third filter box (3); the top of the third filter box (3) is connected to a water inlet pipe (5); the bottom of the first filter box (1) is connected to a water outlet pipe (6); the bottom of one side of the first filter box (1) is fixedly connected to a bottom plate (7); the top of one side of the third filter box (3) is fixedly connected to a top plate (8); and a double-plate mounting frame (9) is fixedly connected between the bottom plate (7) and the top plate (8) and at one end away from the first filter box (1); Three transmission mechanisms (10) are equidistantly provided on the outside of the double-plate mounting frame (9), and push filter mechanisms (11) are provided inside the first filter box (1), the second filter box (2), and the third filter box (3). The transmission mechanisms (10) are used to drive the push filter mechanisms (11). A servo motor (12) is fixedly installed on the top of the bottom plate (7) and at one end away from the first filter box (1). The servo motor (12) is in transmission connection with one of the transmission mechanisms (10) and is used to drive the transmission mechanism (10). A valve assembly (13) is provided on the side of the partition plate (4) close to the double-plate mounting frame (9) for controlling the communication between the first filter box (1), the second filter box (2), and the third filter box (3); The transmission mechanism (10) comprises three first turntables (101) and three second turntables (102) equidistantly arranged outside the double-plate mounting frame (9); the first turntables (101) and the second turntables (102) are fixedly connected via a rotating shaft, and the rotating shaft is rotatably connected to the double-plate mounting frame (9); a fixed rotating rod (103) is fixedly connected to the outer edge of the first turntable (101); an end of the fixed rotating rod (103) away from the first turntable (101) is rotatably connected to a first connecting rod (104); a side of the second turntable (102) away from the first turntable (101) is eccentrically rotatably connected to a second connecting rod (105); and the second connecting rod (105) is eccentrically rotatably connected to the outer side of an adjacent second turntable (102); The output shaft end of the servo motor (12) is fixedly connected to a driving pulley, and a driven pulley is installed on the outer side of the rotating shaft in the transmission mechanism (10) on one side of the first filter box (1), and the servo motor (12) is connected to the transmission mechanism (10) through a belt. The filter pushing mechanism (11) includes a filter plate (111), the first filter box (1), the second filter box (2) and the third filter box (3) are all slidably connected to the inside of the filter plate (111), and one end of the three filter plates (111) close to the double-plate mounting frame (9) is fixedly connected to two slide rods (112), and one end of the slide rod (112) away from the filter plate (111) extends to the outside of the first filter box (1), the second filter box (2) or the third filter box (3) and is fixedly connected to a push plate (113), and the side of the push plate (113) away from the slide rod (112) is rotatably connected to the end of the first connecting rod (104); The valve assembly (13) includes a drain hole (131), and the two partitions (4) are each provided with a drain hole (131) at one end close to the double-plate mounting frame (9), and the interiors of the first filter box (1), the second filter box (2) and the third filter box (3) are all connected to the drain hole (131). A sieve plate (132) is slidably connected to the interior of the partition (4) and at one end close to the double-plate mounting frame (9). A round slider (133) is fixedly connected to the outside of the sieve plate (132) and at the outside of the partition (4). A mounting seat (134) is fixedly connected to the bottom of one side of the second filter box (2) and the third filter box (3). A rotating plate (135) is rotatably connected to one side of the mounting seat (134) via a torsion spring. A sliding groove (136) is provided at the bottom of the rotating plate (135), and the round slider (133) is slidably connected to the sliding groove (136). The servo motor (12) is turned on. When the servo motor (12) drives the first turntable (101) and the second turntable (102) at the bottom to rotate through the belt, the second turntable (102) causes all the second turntables (102) above to rotate synchronously through the second connecting rod (105). At the same time, the second turntable (102) drives the first turntable (101) to rotate through the rotating shaft. When the three first turntables (101) rotate, they push the three push filter mechanisms (11) to slide back and forth left and right through the fixed rotating rod (103) and the first connecting rod (104) to filter the tap water. When the filter plate (111) slides to the right, the water is filtered. When the water is drained, the filter plate (111) slides to the left to wait for the next box of tap water to enter the filter box. When the top When the two push plates (113) slide to the right, the filter plate (111) slides to the right to filter the water. When the push plate (113) is pressed against the second filter box (2) or the third filter box (3), the push plate (113) squeezes the top of the rotating plate (135) to rotate it clockwise. The rotating plate (135) rotates through the chute (136) and the round slider (133) to pull the sieve plate (132) to slide to the left. After the sieve plate (132) slides to the left, the two filter boxes are connected through the water hole (131), and the water flows downward. After the water flows out, the push plate (113) slides to the left, and the rotating plate (135) is reset by the torsion spring to block the water hole (131). At this time, the filter box waits for the water in the water inlet pipe (5) or the previous filter box to flow in, and then the cycle continues.

2. A multi-media filter for tap water treatment and filtration according to claim 1, characterized in that: The three filter plates (111) are filled with activated carbon particles, quartz sand particles, and cotton fibers in sequence from top to bottom.

3. A multi-media filter for tap water treatment and filtration according to claim 1 or 2, characterized in that: A first micro switch (14) is fixedly mounted on the bottom of the top plate (8) and at one end away from the third filter box (3), and a second micro switch (15) is fixedly mounted on the top of the bottom plate (7) and at one end close to the first filter box (1). Electromagnetic valves are installed on the outside of the water inlet pipe (5) and the water outlet pipe (6), the first micro switch (14) is electrically connected to the electromagnetic valve on the outside of the water inlet pipe (5), and the second micro switch (15) is electrically connected to the electromagnetic valve on the outside of the water outlet pipe (6).

4. A multi-media filter for tap water treatment and filtration according to claim 3, characterized in that: The middle portions of the first filter box (1), the second filter box (2) and the third filter box (3) on the side away from the double-plate mounting frame (9) are all connected to a backwash port (16), and the bottom portions of the first filter box (1), the second filter box (2) and the third filter box (3) on the side away from the double-plate mounting frame (9) are all connected to a backwash drain port (17).

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