A sewage pretreatment device convenient for filtering impurities

Abstract

The utility model relates to sewage pretreatment technical field discloses a sewage pretreatment device convenient to filter impurity, including device outer box, the device outer box inside bushing has the anti -overflow cover shell, the anti -overflow cover shell inside bushing has the upper layer connecting ring, the upper layer connecting ring below thread connection has the middle layer connecting ring, the middle layer connecting ring below thread connection has the lower layer connecting ring, the lower layer connecting ring top thread connection has the lower layer connecting column, the lower layer connecting column top clamping has the lower layer filter screen, the lower layer connecting column top bushing has the upper layer connecting column, the upper layer connecting column top clamping has the upper layer filter screen. In the utility model, it adopts the modularization, and each component is connected through simple mode, can tear down and reassemble when some position needs cleaning or replacement faster, and it designs the anti -overflow cover shell structure, can take out the sewage pretreatment structure in the inside more conveniently while preventing sewage overflow to the device outer box.

Description

Technical Field

[0001] This utility model relates to the field of wastewater pretreatment technology, and in particular to a wastewater pretreatment device that facilitates the filtration of impurities. Background Technology

[0002] Wastewater pretreatment units are the front-end treatment units in a wastewater treatment system. Their main function is to initially separate and remove large particulate impurities, suspended solids, grease, and harmful substances from wastewater before it enters the core biological treatment stage. This protects subsequent treatment equipment, improves overall treatment efficiency, and ensures the stable operation of the biological system. Pretreatment is a necessary prerequisite for biological treatment. Without pretreatment, a large amount of suspended solids in the wastewater will cover the surface of the biofilm, hindering mass transfer, while toxic substances will directly kill microorganisms, leading to the collapse of the entire treatment system.

[0003] The existing patent (publication number CN206304094U) discloses "a filtration device for sewage pretreatment, relating to the field of sewage pretreatment technology, including a shell, an inlet pipe, a diversion component, and a filtration component. A filtration chamber is formed inside the shell, and an inlet and an outlet are respectively opened at both ends of the shell; the inlet pipe is installed inside the inlet; the diversion component includes a mounting rod, a diversion block, and a diversion plate, the mounting rod is installed on the shell and connected to the diversion plate, the diversion block is installed on the side of the diversion plate away from the mounting rod, and the diversion block extends at least partially into the inlet pipe; the radial dimension of the diversion block is smaller than the inner diameter of the inlet pipe, and the diversion block is used to evenly divert the sewage discharged through the inlet pipe to the diversion plate; the filtration component includes a first filter screen and a second filter screen, the first filter screen is sleeved on the mounting rod and the periphery of the first filter screen abuts against the inner wall of the shell, the second filter screen is formed in a ring shape, the second filter screen is sleeved outside the diversion plate, and the outer periphery of the first filter screen abuts against the inner wall of the shell." In the process of developing this application, the inventors discovered the following problems with the existing technology: Although the aforementioned wastewater pretreatment filtration device is designed with a structure that can treat wastewater more thoroughly through double-layer filtration, replacing the filter mesh is rather cumbersome, requiring the entire device to be disassembled. This takes time and affects the efficiency of use.

[0004] Therefore, those skilled in the art have provided a wastewater pretreatment device that facilitates the filtration of impurities to solve the problems mentioned in the background art. Utility Model Content

[0005] The purpose of this utility model is to address the shortcomings of existing technologies by proposing a wastewater pretreatment device that facilitates the filtration of impurities. Its advantages include modular design, with each component connected in a simple manner. When a certain part needs to be cleaned or replaced, it can be quickly disassembled and reassembled. Furthermore, it is designed with an overflow-proof cover structure, which can prevent wastewater from overflowing into the outer casing of the device while making it easier to remove the internal wastewater pretreatment structure.

[0006] To achieve the above objectives, this utility model provides the following technical solution: a wastewater pretreatment device for convenient filtration of impurities, comprising an outer casing, an overflow-proof cover fitted inside the outer casing, an upper connecting ring fitted inside the overflow-proof cover, a middle connecting ring threaded below the upper connecting ring, a lower connecting ring threaded below the middle connecting ring, a lower connecting post threaded above the bottom of the lower connecting ring, a lower filter screen snapped onto the top of the lower connecting post, and an upper connecting post fitted onto the top of the lower connecting post. The top of the column is fitted with an upper filter screen. The upper connecting column includes an upper connecting column body. An internal thread of the upper connecting column is fixedly provided inside the upper part of the upper connecting column body. An insertion port of the upper connecting column is fixedly provided below the upper connecting column body. The lower connecting column includes a lower connecting column body. A lower connecting column insertion post is fixedly provided above the lower connecting column body. The lower connecting column insertion post and the upper connecting column insertion post are sleeved together. An internal thread of the lower connecting column is fixedly provided above the lower connecting column body at a position outside the lower connecting column insertion post.

[0007] Furthermore, the upper filter screen includes an upper filter screen body, a water guide block is fixedly installed at the upper center of the upper filter screen body, three upper filter screen fixing insertion posts are fixedly installed around the lower perimeter of the upper filter screen body, and an upper filter screen connecting threaded port is fixedly installed at the lower center of the upper filter screen body, and the upper filter screen connecting threaded port and the upper connecting post are threadedly connected.

[0008] Furthermore, the lower filter screen includes a lower filter screen body, three lower filter screen fixing insertion posts are fixedly arranged around the lower part of the lower filter screen body, a lower filter screen insertion port is fixedly arranged in the lower center of the lower filter screen body, and a lower filter screen hollow threaded port is fixedly arranged at the lower part of the lower filter screen body outside the lower filter screen insertion port. The lower filter screen hollow threaded port and the lower connecting post are threadedly connected.

[0009] Furthermore, the lower connecting ring includes a lower connecting ring body, and a lower filter screen placement groove is fixedly provided at the inner position of the top of the lower connecting ring body. Three lower filter screen fixing grooves are fixedly provided around the top of the lower filter screen placement groove, and the three lower filter screen fixing grooves are engaged with the lower filter screen fixing insertion post.

[0010] Furthermore, the lower connecting ring body has an internal thread fixedly installed at the top of the lower connecting ring body located outside the lower filter screen placement groove. The lower connecting ring body has a fixed base plate below it. The lower connecting ring base plate has a fixed connecting insertion post at the bottom center of the bottom of the lower connecting ring base plate. The lower connecting ring outlet is fixedly installed at the bottom of the lower connecting ring base plate.

[0011] Furthermore, a lower connecting post insertion port is fixedly provided at the bottom of the lower connecting post body, and the lower connecting ring connects the insertion post and the lower connecting post insertion port.

[0012] Furthermore, the middle connecting ring includes a middle connecting ring body, and an upper filter screen placement groove is fixedly provided at the inner position of the top of the middle connecting ring body. Three upper filter screen fixing grooves are fixedly provided around the top of the upper filter screen placement groove, and the three upper filter screen fixing grooves are engaged with the upper filter screen fixing insertion post.

[0013] Furthermore, the top of the middle connecting ring body is fixedly provided with an internal thread of the middle connecting ring located outside the upper filter screen placement groove, and a hollow threaded opening of the middle connecting ring is fixedly provided below the middle connecting ring body, and the hollow threaded opening of the middle connecting ring is threadedly connected to the internal thread of the lower connecting ring.

[0014] Furthermore, the upper connecting ring includes an upper connecting ring body, and a hollow threaded opening of the upper connecting ring is fixedly provided below the upper connecting ring body. The hollow threaded opening of the upper connecting ring is threadedly connected to the internal thread of the middle connecting ring.

[0015] Furthermore, the overflow cover includes an overflow cover body, with handles fixedly installed on both sides of the upper part of the overflow cover body, and an overflow cover outlet fixedly installed at the bottom of the overflow cover body. The outer casing of the device includes an outer casing body, with an outer casing cover hinged to the top of the outer casing body. An outer casing inlet is fixedly installed at the top center of the outer casing cover, and an outer casing outlet is fixedly installed inside the bottom center of the outer casing body. Four outer casing support pillars are fixedly connected around the bottom of the outer casing body.

[0016] This utility model has the following beneficial effects: This utility model proposes a wastewater pretreatment device that facilitates the filtration of impurities. It adopts a modular design, with each component connected by simple methods such as threaded rotation and snap-fit. When a certain part needs to be cleaned or replaced, it can be quickly disassembled and reassembled. Furthermore, it is equipped with an overflow-proof cover structure to prevent wastewater from overflowing into the outer casing of the device during the treatment process. At the same time, by simply lifting the overflow-proof cover, all the internal wastewater treatment components can be removed without disassembling the outer casing of the device. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the outer casing and spill-proof cover structure of the device of this utility model; Figure 2 This is a schematic diagram of the internal structure of the outer casing of the device of this utility model; Figure 3 This is a schematic diagram of the internal structure of the spill containment cover of this utility model; Figure 4 This is a schematic diagram of the upper filter structure of this utility model; Figure 5 This is a schematic diagram of the lower filter structure of this utility model; Figure 6 This is a schematic diagram of the upper connecting column structure of this utility model; Figure 7 This is a schematic diagram of the lower connecting column structure of this utility model; Figure 8 This is a schematic diagram of the upper connecting ring structure of this utility model; Figure 9 This is a schematic diagram of the middle layer connecting ring structure of this utility model; Figure 10 This is a schematic diagram of the lower connecting ring structure of this utility model; Figure 11 This is a schematic diagram of the cross-sectional structure of the connecting ring of this utility model.

[0018] Legend: 1. Outer casing; 101. Outer casing body; 102. Outer casing outlet; 103. Outer casing support; 104. Outer casing cover; 105. Outer casing inlet; 2. Overflow cover; 201. Overflow cover body; 202. Handle; 203. Overflow cover outlet; 3. Upper connecting ring; 301. Upper connecting ring body; 302. Hollow threaded opening of upper connecting ring; 4. Middle connecting ring; 401. Middle connecting ring body; 402. Upper filter screen placement slot; 403. Upper filter screen fixing groove; 404. Hollow threaded opening of middle connecting ring; 405. Internal thread of middle connecting ring; 5. Lower connecting ring; 501. Lower connecting ring body; 502. Lower filter screen placement slot; 503. Lower filter screen fixing groove; 504. Lower connecting ring connection insertion. Column; 505, Lower connecting ring outlet; 506, Lower connecting ring internal thread; 507, Lower connecting ring base plate; 6, Upper filter screen; 601, Upper filter screen body; 602, Upper filter screen fixing insertion post; 603, Upper filter screen connection threaded port; 604, Water guide block; 7, Lower filter screen; 701, Lower filter screen body; 702, Lower filter screen fixing insertion post; 703, Lower filter screen insertion port; 704, Lower filter screen hollow threaded port; 8, Upper connecting post; 801, Upper connecting post internal thread; 802, Upper connecting post body; 803, Upper connecting post insertion port; 9, Lower connecting post; 901, Lower connecting post insertion post; 902, Lower connecting post internal thread; 903, Lower connecting post body; 904, Lower connecting post insertion port. Detailed Implementation

[0019] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0020] Reference Figure 1 , Figure 4 , Figure 5 , Figure 6 , Figure 7 , Figure 8 , Figure 9 , Figure 10This utility model provides an embodiment of a wastewater pretreatment device for convenient filtration of impurities, comprising an outer casing 1, an overflow cover 2 fitted inside the outer casing 1, an upper connecting ring 3 fitted inside the overflow cover 2, a middle connecting ring 4 threaded below the upper connecting ring 3, a lower connecting ring 5 threaded below the middle connecting ring 4, a lower connecting post 9 threaded above the bottom of the lower connecting ring 5, a lower filter screen 7 snapped onto the top of the lower connecting post 9, an upper connecting post 8 fitted onto the top of the lower connecting post 9, and an upper filter screen 6 snapped onto the top of the upper connecting post 8. The upper connecting column 9 includes an upper connecting column body 802, an upper connecting column internal thread 801 fixedly installed inside the upper connecting column body 802, and an upper connecting column insertion port 803 fixedly installed below the upper connecting column body 802. The lower connecting column 9 includes a lower connecting column body 903, a lower connecting column insertion post 901 fixedly installed above the lower connecting column body 903, the lower connecting column insertion post 901 and the upper connecting column insertion port 803 are sleeved together, and a lower connecting column internal thread 902 is fixedly installed on the upper part of the lower connecting column body 903 at the position outside the lower connecting column insertion post 901.

[0021] Specifically, the overflow cover 2 can be fitted into the outer casing 1 of the device, and the upper connecting ring 3, middle connecting ring 4, and lower connecting ring 5 are connected together by screwing. The lower connecting post 9 is inserted above the bottom of the lower connecting ring 5. The upper filter screen 6 is made of stainless steel with a large pore size, which can effectively intercept larger solid floating particles and also plays an important role in separating solids and liquids. The lower filter screen 7 is made of PP cotton, which can effectively intercept finer particles such as mud, rust, and suspended solids. Inserting the lower connecting post 901 into the upper connecting post insertion port 803 allows the lower connecting post 9 and the upper connecting post 8 to engage. The lower connecting post 9 is inserted to the bottom of the lower connecting ring 5.

[0022] Reference Figure 5 , Figure 7 , Figure 10The lower filter 7 includes a lower filter body 701. Three lower filter fixing insertion posts 702 are fixedly installed around the lower part of the lower filter body 701. A lower filter insertion port 703 is fixedly installed in the center of the lower part of the lower filter body 701. A hollow threaded port 704 is fixedly installed below the lower filter body 701, outside the lower filter insertion port 703. The hollow threaded port 704 is threadedly connected to the internal thread 902 of the lower connecting post. The lower connecting ring 5 includes a lower connecting ring body 501. A lower filter placement groove 502 is fixedly installed at the inner part of the top of the lower connecting ring body 501. Three lower filter insertion posts are fixedly installed around the top of the lower filter placement groove 502. The lower filter screen fixing groove 503 is engaged with the lower filter screen fixing insertion post 702. The lower connecting ring body 501 is fixedly provided with an internal thread 506 at the position outside the lower filter screen placement groove 502. The lower connecting ring base plate 507 is fixedly provided below the lower connecting ring body 501. The lower connecting ring connecting insertion post 504 is fixedly provided at the bottom center of the lower connecting ring base plate 507. The lower connecting ring outlet 505 is fixedly provided at the bottom of the lower connecting ring base plate 507. The lower connecting post insertion port 904 is fixedly provided at the bottom of the lower connecting post body 903. The lower connecting ring connecting insertion post 504 and the lower connecting post insertion port 904 are engaged.

[0023] Specifically, the hollow threaded opening 704 of the lower filter screen is inserted into the inner thread 902 of the lower connecting post and tightened to fix the lower filter screen 7 and the lower connecting post 9. The lower connecting post insertion post 901 passes through the lower filter screen insertion opening 703. The lower connecting post body 903 is placed above the lower connecting ring base plate 507, and the lower connecting ring connecting insertion post 504 and the lower connecting post insertion opening 904 are threaded together to connect the lower connecting ring 5 and the lower connecting post 9. The lower filter screen body 701 is placed above the lower filter screen placement groove 502, and the lower filter screen fixing insertion post 702 is inserted into the lower filter screen fixing groove 503 to fix the lower filter screen 7 and the lower connecting ring 5. The lower connecting ring outlet 505 can discharge the filtered wastewater.

[0024] Reference Figure 4 , Figure 9 , Figure 11The upper filter screen 6 includes an upper filter screen body 601. A water guide block 604 is fixedly installed at the center of the upper filter screen body 601. Three upper filter screen fixing insertion posts 602 are fixedly installed around the lower part of the upper filter screen body 601. An upper filter screen connecting threaded port 603 is fixedly installed at the center of the lower part of the upper filter screen body 601. The upper filter screen connecting threaded port 603 is threadedly connected to the internal thread 801 of the upper connecting post. The middle connecting ring 4 includes a middle connecting ring body 401. An upper connecting ring is fixedly installed at the inner part of the top of the middle connecting ring body 401. The upper filter screen placement groove 402 has three upper filter screen fixing grooves 403 fixedly installed around the top of the upper filter screen placement groove 402. The three upper filter screen fixing grooves 403 are engaged with the upper filter screen fixing insertion post 602. The top of the middle connecting ring body 401 is fixedly provided with the middle connecting ring internal thread 405 at the position outside the upper filter screen placement groove 402. The lower part of the middle connecting ring body 401 is fixedly provided with the middle connecting ring hollow threaded opening 404. The middle connecting ring hollow threaded opening 404 is threadedly connected with the lower connecting ring internal thread 506.

[0025] Specifically, the upper filter screen connecting thread 603 is inserted into the upper connecting post thread 801 and tightened, thereby fixing the upper filter screen 6 onto the upper connecting post 8. The water guide block 604 guides the sewage flowing from above into the center of the upper filter screen body 601 to the mesh on both sides. The upper filter screen body 601 is placed into the upper filter screen placement groove 402, and the upper filter screen fixing insertion post 602 can be inserted into the upper filter screen fixing groove 403, thereby fixing the upper filter screen 6 onto the middle connecting ring 4. The hollow threaded end 404 of the middle connecting ring is inserted into the lower connecting ring thread 506 and tightened, thereby fixing the middle connecting ring 4 above the lower connecting ring 5.

[0026] Reference Figure 8 , Figure 11 The upper connecting ring 3 includes an upper connecting ring body 301, and a hollow threaded opening 302 of the upper connecting ring is fixedly provided below the upper connecting ring body 301. The hollow threaded opening 302 of the upper connecting ring is threadedly connected to the inner thread 405 of the middle connecting ring.

[0027] Specifically, the hollow threaded opening 302 of the upper connecting ring is inserted into the inner thread 405 of the middle connecting ring and screwed in, so that the upper connecting ring 3 is fixed above the middle connecting ring 4.

[0028] Reference Figure 1 , Figure 2 , Figure 3The overflow cover 2 includes an overflow cover body 201, with handles 202 fixedly installed on both sides of the upper part of the overflow cover body 201, and an overflow cover outlet 203 fixedly installed at the bottom of the overflow cover body 201. The outer box 1 includes an outer box body 101, with an outer box cover 104 hinged to the top of the outer box body 101, an outer box inlet 105 fixedly installed at the top center of the outer box cover 104, an outer box outlet 102 fixedly installed inside the bottom center of the outer box body 101, and four outer box support pillars 103 fixedly connected around the bottom of the outer box body 101.

[0029] Specifically, the overflow cover 2 prevents internal sewage from seeping into the outer casing 1. By grasping the handle 202, aligning the overflow cover outlet 203 with the outer casing outlet 102, the overflow cover body 201 is inserted into the outer casing body 101. A water pipe can be inserted into the outer casing inlet 105 to pour untreated sewage into it. The outer casing support column 103 is placed on the ground for support.

[0030] Working principle: The hollow threaded opening 704 of the lower filter screen is inserted into the inner thread 902 of the lower connecting post and screwed in, thereby fixing the lower filter screen 7 and the lower connecting post 9. The lower connecting post insertion post 901 passes through the lower filter screen insertion opening 703. The lower connecting ring connecting insertion post 504 and the lower connecting post insertion opening 904 are engaged, thereby connecting the lower connecting ring 7 and the lower connecting post 9. The lower filter screen body 701 is now located above the lower filter screen placement groove 502. The lower filter screen fixing insertion post 702 is inserted into the lower filter screen fixing groove 503, thereby fixing the lower filter screen 7 and the lower connecting ring 5. The hollow threaded opening 404 of the middle connecting ring is inserted into the inner thread 506 of the lower connecting ring and screwed in, so that the middle connecting ring 4 is fixed above the lower connecting ring 5. The upper filter screen connection thread 603 is inserted into the upper connecting post thread 801 and screwed in, thereby fixing the upper filter screen 6 onto the upper connecting post 8. The lower connecting post insertion post 901 is inserted into the upper connecting post insertion port 803, allowing the lower connecting post 9 and the upper connecting post insertion post 8 to engage. The upper filter screen fixing insertion post 602 can be inserted into the upper filter screen fixing groove 403, thereby fixing the upper filter screen 6 onto the middle connecting ring 4. The hollow threaded port 302 of the upper connecting ring is inserted into the middle connecting ring thread 405 and screwed in, thereby fixing the upper connecting ring 3 above the middle connecting ring 4. At this point, all the internal structures are assembled. Each part of the connecting ring and the filter screen in contact is equipped with a sealing ring to prevent water from flowing out along the gaps. The assembled structure is placed into the overflow cover 2, and the lower connecting ring outlet 505 is inserted into the overflow cover outlet 203. Grasp handle 202, align the overflow cover outlet 203 with the outer tank outlet 102, and insert it to place the overflow cover body 201 inside the outer tank body 101. A water pipe can be inserted into the outer tank inlet 105 to pour untreated wastewater into it. The outer tank support pillar 103 is placed on the ground for support. Wastewater is poured into the outer tank inlet 105, where it passes through the upper filter screen 6 to separate solid floating matter, and then through the lower filter screen 7 to intercept finer particles. The pre-treated wastewater then flows out through the lower connecting ring outlet 505. When disassembly is required, open the outer tank cover 104 and remove the overflow cover 2 to disassemble the internal structure.

[0031] Finally, it should be noted that the above are merely preferred embodiments of the present utility model and are not intended to limit the present utility model. Although the present utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A wastewater pretreatment device for convenient filtration of impurities, comprising an outer casing (1), characterized in that: An overflow cover (2) is fitted inside the outer casing (1) of the device. An upper connecting ring (3) is fitted inside the overflow cover (2). A middle connecting ring (4) is threaded below the upper connecting ring (3). A lower connecting ring (5) is threaded below the middle connecting ring (4). A lower connecting post (9) is threaded above the bottom of the lower connecting ring (5). A lower filter screen (7) is snapped onto the top of the lower connecting post (9). An upper connecting post (8) is fitted onto the top of the lower connecting post (9). An upper filter screen (6) is snapped onto the top of the upper connecting post (8). The upper connecting post (8) includes an upper connecting post body (802). The upper connecting column body (802) is fixedly provided with an upper connecting column internal thread (801) inside, and the upper connecting column insertion port (803) is fixedly provided below the upper connecting column body (802). The lower connecting column (9) includes a lower connecting column body (903), and a lower connecting column insertion post (901) is fixedly provided above the lower connecting column body (903). The lower connecting column insertion post (901) and the upper connecting column insertion port (803) are sleeved together. The lower connecting column internal thread (902) is fixedly provided above the lower connecting column body (903) at a position outside the lower connecting column insertion post (901).

2. The wastewater pretreatment device for conveniently filtering impurities according to claim 1, characterized in that: The upper filter screen (6) includes an upper filter screen body (601), a water guide block (604) is fixedly installed in the middle of the upper part of the upper filter screen body (601), three upper filter screen fixing insertion posts (602) are fixedly installed around the lower part of the upper filter screen body (601), and an upper filter screen connecting threaded port (603) is fixedly installed in the center of the lower part of the upper filter screen body (601). The upper filter screen connecting threaded port (603) is threadedly connected to the inner thread (801) of the upper connecting post.

3. The wastewater pretreatment device for conveniently filtering impurities according to claim 1, characterized in that: The lower filter (7) includes a lower filter body (701), three lower filter fixing insertion posts (702) are fixedly arranged around the lower part of the lower filter body (701), a lower filter insertion port (703) is fixedly arranged in the middle of the lower part of the lower filter body (701), and a lower filter hollow threaded port (704) is fixedly arranged at the position outside the lower filter insertion port (703) below the lower filter body (701). The lower filter hollow threaded port (704) is threadedly connected to the lower connecting post internal thread (902).

4. The wastewater pretreatment device for conveniently filtering impurities according to claim 1, characterized in that: The lower connecting ring (5) includes a lower connecting ring body (501). A lower filter screen placement groove (502) is fixedly provided at the inner position of the top of the lower connecting ring body (501). Three lower filter screen fixing grooves (503) are fixedly provided around the top of the lower filter screen placement groove (502). The three lower filter screen fixing grooves (503) are engaged with the lower filter screen fixing insertion post (702).

5. A wastewater pretreatment device for conveniently filtering impurities according to claim 4, characterized in that: The lower connecting ring body (501) is fixedly provided with an internal thread (506) at the top of the lower connecting ring body (501) outside the lower filter screen placement groove (502). The lower connecting ring base plate (507) is fixedly provided below the lower connecting ring body (501). The lower connecting ring connecting insertion post (504) is fixedly provided at the bottom center of the lower connecting ring base plate (507). The lower connecting ring outlet (505) is fixedly provided at the bottom of the lower connecting ring base plate (507).

6. The wastewater pretreatment device for conveniently filtering impurities according to claim 1, characterized in that: The bottom of the lower connecting column body (903) is fixedly provided with a lower connecting column insertion port (904), and the lower connecting ring connects the insertion column (504) and the lower connecting column insertion port (904) in a snap-fit ​​manner.

7. A wastewater pretreatment device for conveniently filtering impurities according to claim 1, characterized in that: The middle connecting ring (4) includes a middle connecting ring body (401). An upper filter placement groove (402) is fixedly provided at the inner position of the top of the middle connecting ring body (401). Three upper filter fixing grooves (403) are fixedly provided around the top of the upper filter placement groove (402). The three upper filter fixing grooves (403) are engaged with the upper filter fixing insertion post (602).

8. A wastewater pretreatment device for conveniently filtering impurities according to claim 7, characterized in that: The top of the middle connecting ring body (401) is fixedly provided with an internal thread (405) outside the upper filter screen placement groove (402), and a hollow threaded opening (404) of the middle connecting ring is fixedly provided below the middle connecting ring body (401). The hollow threaded opening (404) of the middle connecting ring and the internal thread (506) of the lower connecting ring are threadedly connected.

9. A wastewater pretreatment device for conveniently filtering impurities according to claim 1, characterized in that: The upper connecting ring (3) includes an upper connecting ring body (301), and a hollow threaded opening (302) of the upper connecting ring is fixedly provided below the upper connecting ring body (301). The hollow threaded opening (302) of the upper connecting ring and the inner thread (405) of the middle connecting ring are threadedly connected.

10. A wastewater pretreatment device for conveniently filtering impurities according to claim 1, characterized in that: The overflow cover (2) includes an overflow cover body (201), handles (202) are fixedly installed on both sides of the upper part of the overflow cover body (201), and an overflow cover outlet (203) is fixedly installed at the bottom of the overflow cover body (201). The outer box (1) of the device includes an outer box body (101), an outer box cover (104) is hinged to the top of the outer box body (101), an outer box inlet (105) is fixedly installed at the top center of the outer box cover (104), an outer box outlet (102) is fixedly installed inside the bottom center of the outer box body (101), and four outer box support pillars (103) are fixedly connected around the bottom of the outer box body (101).

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