Well washing and sampling device for underground water detection

Abstract

The utility model discloses a well washing and sampling device for underground water detection, which comprises a submersible pump, the upper end of the submersible pump is connected with an air bag through a suspension connecting piece, the air bag floats on the water surface of an underground water well and suspends the submersible pump, and a sediment filtering device is arranged at a water inlet at the lower end of the submersible pump. An elastic tensioning mechanism is fixed to the ground of the underground water well, the air bag is fixedly connected with one end of a traction rope, the other end of the traction rope is wound around the elastic tensioning mechanism, and a length measuring device for measuring the moving distance of the traction rope is arranged on the elastic tensioning mechanism. A water outlet of the submersible pump is communicated with a water inlet of a closed water sample collecting barrel through a water outlet pipeline, an outlet of the water sample collecting barrel is connected with a sampling pipeline, a secondary filtering device is arranged in the water sample collecting barrel, a flow regulating valve and a flow meter are arranged on the sampling pipeline, and a pipe joint is arranged at the tail end of the sampling pipeline; the device can guarantee the accuracy of the sampling depth of the submersible pump and can monitor the height of the underground water level in real time.

Description

Technical Field

[0001] This utility model relates to the field of groundwater sampling and testing technology, and in particular to a well washing and sampling device for groundwater testing. Background Technology

[0002] When sampling groundwater, a groundwater well is usually dug at the testing site first. After a period of time, the surrounding groundwater will collect into the well. Then, a small water pump is used to pump the groundwater into the well and start the pump to pump out the old water from the well for well flushing. While the well is being flushed, new groundwater will gradually collect into the well. Sampling begins four hours after the well is flushed.

[0003] According to the sampling standards, the water pump should be used to sample at a depth of 0.5m below the water level, and the sampling speed should be controlled between 100-500ml / min. At the same time, the water level in the well should not drop significantly, and the drop depth should not exceed 10cm.

[0004] Currently, sampling can only be controlled manually. This involves manually lowering the water pump underwater using a rope and manually checking the length of the rope to ensure that the pump is at least 0.5m below the water level. While manually pulling the pump, the pump waits for the water to drop. However, it is difficult to observe the rate and height of the water level drop during the sampling process. Furthermore, when the water level drops, the actual sampling depth of the pump may be less than 0.5m, and manual adjustments are neither timely nor accurate.

[0005] In addition, water quality varies from region to region. Groundwater may contain sediment, which can be carried up by the water pump during sampling, thus affecting water quality testing and requiring additional removal steps. Utility Model Content

[0006] The technical problem to be solved by this utility model is to provide a well washing and sampling device for groundwater detection, which can ensure the accuracy of the sampling depth of the submersible pump while also monitoring the height of the groundwater level in real time.

[0007] To solve the above-mentioned technical problems, the technical solution of this utility model is: a well-washing and sampling device for groundwater testing, including a submersible pump. The upper end of the submersible pump is connected to an airbag via a suspension connector. The airbag floats on the surface of the groundwater well. A sediment filtration device is installed at the water inlet at the lower end of the submersible pump. An elastic tensioning mechanism is fixed on the ground of the groundwater well. One end of the airbag is fixedly connected to a traction rope. The other end of the traction rope is wound around the elastic tensioning mechanism. A length measuring device for measuring the movement distance of the traction rope is installed on the elastic tensioning mechanism. The water outlet of the submersible pump is connected to the water inlet of a closed water sample collection bucket via an outlet pipe. A sampling pipe is connected to the outlet of the water sample collection bucket. A secondary filtration device is installed inside the water sample collection bucket. A flow regulating valve and a flow meter are installed on the sampling pipe. A pipe joint is installed at the end of the sampling pipe.

[0008] As a preferred embodiment, the elastic tensioning mechanism includes a base, a mounting seat fixedly mounted on the base, a central shaft provided on the mounting seat, a take-up and untake-up reel rotatably mounted on the central shaft, an elastic locking structure for elastically locking the take-up and untake-up reel on the central shaft, and an operating handle fixedly mounted on the take-up and untake-up reel.

[0009] As a preferred embodiment, the elastic locking structure includes a first spring fitted on the central shaft and located outside the take-up and unwinding reels, and a locking nut that compresses the first spring is rotatably mounted on the central shaft.

[0010] As a preferred embodiment, the mounting base is provided with a locking groove, the base is provided with a top panel, the locking groove is locked onto the top panel, a locking screw is installed on the groove wall of the locking groove, a clamping block is provided at the lower end of the locking screw, and an operating rod is provided at the upper end of the locking screw.

[0011] As a preferred embodiment, the length measuring device includes an upper pressure wheel and a lower pressure wheel rotatably mounted on the base, with a through gap between the upper and lower pressure wheels, through which the traction rope passes and is squeezed by the upper and lower pressure wheels, and the upper or lower pressure wheel is connected to a pulse encoder.

[0012] As a preferred embodiment, the lower pressing wheel is rotatably mounted on the lower wheel seat, the lower wheel seat is fixed on the machine base, the upper pressing wheel is rotatably mounted on the upper wheel seat, the upper wheel seat is vertically slidably mounted on the machine base via a vertical guide rod, and a second spring is fitted on the vertical guide rod, the elastic force of the second spring forcing the upper pressing wheel and the lower pressing wheel to cooperate with each other.

[0013] As a preferred embodiment, the upper wheel seat is a rectangular seat with the opening facing downwards. The upper pressing wheel is rotatably mounted between the left and right walls of the upper wheel seat. The lower part of the left and right walls is lower than the lower end of the upper pressing wheel. The upper end of the lower pressing wheel extends into the range of the left and right walls and cooperates with the upper pressing wheel.

[0014] As a preferred embodiment, the sediment filtration device includes a sediment filter cover that is wrapped around the water inlet at the lower end of the submersible pump and fixed by fasteners, and the sediment filter cover is provided with a plurality of filter holes.

[0015] As a preferred embodiment, the water sample collection bucket includes a bucket body and a bucket lid, the bucket lid being detachably fixed to the bucket body. The secondary filtration device includes a hollow filter cartridge installed inside the bucket body. A support frame is provided inside the bucket body to support the filter cartridge from the outside. The inlet and outlet are both located at the upper end of the bucket body. An inlet pipe is provided inside the bucket body, one end of which is connected to the inlet, and the other end extends into the interior of the filter cartridge. The outlet is connected to the external space of the filter cartridge.

[0016] After adopting the above technical solution, the effect of this utility model is as follows: A well-washing and sampling device for groundwater testing includes a submersible pump. The upper end of the submersible pump is connected to an airbag via a suspension connector. The airbag floats on the surface of the groundwater well. A sediment filtration device is installed at the water inlet at the lower end of the submersible pump. An elastic tensioning mechanism is fixed on the ground surface of the groundwater well. One end of the airbag is fixedly connected to a traction rope, and the other end of the traction rope is wound around the elastic tensioning mechanism. A length measuring device for measuring the movement distance of the traction rope is installed on the elastic tensioning mechanism. The outlet of the submersible pump... The water outlet pipe is connected to the inlet of the closed water sample collection bucket, and the outlet of the water sample collection bucket is connected to a sampling pipe. The water sample collection bucket is equipped with a secondary filtration device, and the sampling pipe is equipped with a flow regulating valve and a flow meter. The end of the sampling pipe is equipped with a pipe joint. Therefore, when the inflatable airbag and the submersible pump are placed together in the water of the groundwater well, the buoyancy of the airbag can suspend the submersible pump. By selecting a suitable length of suspension connector, it can be ensured that the sampling port of the submersible pump is always 0.5m below the water level. At the same time, the sediment filtration device can effectively filter sediment and reduce sediment interference. The airbag is fixedly connected to one end of the traction rope, and the other end of the traction rope is wound around the elastic tensioning mechanism. The elastic tensioning mechanism is equipped with a length measuring device to measure the movement distance of the traction rope. In this way, the traction rope is only tensioned by the elastic tensioning mechanism, and when the water level drops, the airbag will descend. At this time, the airbag will pull the traction rope, and the length measuring device will detect the movement distance of the traction rope, thereby monitoring the drop in water level in real time and ensuring that the entire sampling process is within the prescribed standard procedures to ensure the accuracy of the sampling. The sampled groundwater flows out through the sampling pipe, and the pipe joint can be connected to a burette for VOCs detection or to a parallel sampling pipe for parallel sampling.

[0017] Furthermore, since the elastic tensioning mechanism includes a base, a mounting seat is fixedly mounted on the base, a central shaft is provided on the mounting seat, a take-up and untake-up reel is rotatably mounted on the central shaft, an elastic locking structure is provided on the central shaft to elastically lock the take-up and untake-up reel, an operating handle is fixed on the take-up and untake-up reel, and the elastic locking structure includes a first spring sleeved on the central shaft and located outside the take-up and untake-up reel, and a locking nut that presses the first spring is rotatably mounted on the central shaft. Therefore, the first spring can be adjusted by rotating the locking nut. The tension of the first spring is adjusted by controlling the compression of the coil, which in turn adjusts the rotational resistance of the winding reel. This keeps the traction rope taut. When the water level drops, the submersible pump and airbag descend, pulling the traction rope. The traction rope then overcomes the rotational resistance, causing the winding reel to rotate. This allows the length measuring device to detect the length of the traction rope's movement, thus accurately monitoring the drop in water level. After sampling, the entire device can be lifted out of the well by hand-cranking the winding reel, making it easier to retrieve the submersible pump.

[0018] Furthermore, since the mounting base is provided with a locking slot and the base is provided with a top panel, the locking slot is locked onto the top panel, a locking screw is installed on the groove wall of the locking slot, a clamping block is provided at the lower end of the locking screw, and an operating rod is provided at the upper end of the locking screw. The mounting base is easy to install and can be directly disassembled when not in use, making it convenient to carry and move.

[0019] Furthermore, the length measuring device includes an upper pressure wheel and a lower pressure wheel rotatably mounted on the base, with a through gap between them. The traction rope passes through and is squeezed by the upper and lower pressure wheels. The upper or lower pressure wheel is connected to a pulse encoder. By squeezing the traction rope with the upper and lower pressure wheels, the movement of the traction rope causes the upper and lower pressure wheels to rotate. The pulse encoder converts the change in rotation angle into electrical pulses, and then calculates the actual displacement based on the circumference of the upper or lower pressure wheel. This structure allows for accurate detection of the traction rope's displacement.

[0020] Furthermore, since the lower pressure wheel is rotatably mounted on the lower wheel seat, which is fixed on the machine base, and the upper pressure wheel is rotatably mounted on the upper wheel seat, which is vertically slidably mounted on the machine base via a vertical guide rod, and a second spring is fitted on the vertical guide rod, the elastic force of the second spring forces the upper pressure wheel and the lower pressure wheel to cooperate with each other, thus the elastic force of the second spring can force the upper pressure wheel and the lower pressure wheel to cooperate with each other to press the traction rope.

[0021] Furthermore, since the upper wheel seat is a rectangular seat with its opening facing downwards, the upper pressure wheel is rotatably mounted between the left and right walls of the upper wheel seat. The lower part of the left and right walls is lower than the lower end of the upper pressure wheel, and the upper end of the lower pressure wheel extends into the range of the left and right walls and cooperates with the upper pressure wheel. In this way, the left and right walls will block the gap on both sides, thereby preventing the traction rope from coming off.

[0022] Furthermore, the sediment filtration device includes a sediment filter cover that is wrapped around the water inlet at the lower end of the submersible pump and fixed by fasteners. The sediment filter cover is provided with a number of filter holes, which can perform coarse filtration of sediment.

[0023] Furthermore, since the water sample collection bucket includes a bucket body and a bucket lid, the bucket lid is detachably fixed to the bucket body. The secondary filtration device includes a hollow filter cartridge installed inside the bucket body. A support frame is provided inside the bucket body to support the filter cartridge from the outside. The inlet and outlet are both located at the upper end of the bucket body. An inlet pipe is provided inside the bucket body. One end of the inlet pipe is connected to the inlet, and the other end extends into the inside of the filter cartridge. The outlet is connected to the external space of the filter cartridge. Therefore, the groundwater pumped by the submersible pump enters the internal space of the filter cartridge inside the bucket body. The groundwater undergoes secondary filtration by the filter cartridge. The filtered groundwater enters the external space of the filter cartridge and finally flows into the sampling pipe from the outlet, reducing the impact of sediment on the sampled water. Attached Figure Description

[0024] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0025] Figure 1 This is a structural schematic diagram of an embodiment of the present utility model;

[0026] Figure 2 This is a schematic diagram of the structure of the airbag and submersible pump according to an embodiment of the present invention;

[0027] Figure 3 This is a perspective view of the elastic tensioning mechanism according to an embodiment of the present invention;

[0028] Figure 4 This is a front view of the elastic tensioning mechanism according to an embodiment of the present invention;

[0029] Figure 5 This is a perspective view of the elastic tensioning mechanism of this utility model embodiment from another angle;

[0030] Figure 6 This is a schematic diagram of the structure of the water sample collection bucket according to an embodiment of the present invention;

[0031] In the attached diagram: 1. Submersible pump; 2. Suspension connector; 3. Airbag; 4. Groundwater well; 5. Sediment filtration device; 6. Elastic tensioning mechanism; 61. Base; 611. Top panel; 62. Mounting base; 621. Mounting slot; 63. Central shaft; 64. Winding reel; 65. Operating handle; 66. First spring; 67. Locking nut; 68. Locking screw; 69. Operating lever; 610. Pressure block; 7. Traction. 8. Rope; 9. Water sample collection bucket; 10. Bucket body; 11. Bucket lid; 12. Filter cartridge; 13. Support frame; 14. Inlet pipe; 15. Sampling pipe; 16. Flow regulating valve; 17. Flow meter; 18. Pipe connector; 19. Upper pressure reel; 10. Lower pressure reel; 10. Upper reel seat; 11. Left side wall; 12. Right side wall; 13. Lower reel seat; 14. Pulse encoder; 15. Second spring; 16. Outlet pipe. Detailed Implementation

[0032] The present invention will be further described in detail below through specific embodiments.

[0033] like Figure 1-6 As shown, a well-washing and sampling device for groundwater testing includes a submersible pump 1. The upper end of the submersible pump 1 is connected to an airbag 3 via a suspension connector 2. The airbag 3 floats on the water surface of a groundwater well 4. A sediment filter 5 is installed at the water inlet at the lower end of the submersible pump 1. An elastic tensioning mechanism 6 is fixed on the ground surface of the groundwater well 4. The airbag 3 and the elastic tensioning mechanism 6 are connected by a traction rope 7. A length measuring device for measuring the movement distance of the traction rope 7 is installed on the elastic tensioning mechanism 6. The water outlet of the submersible pump 1 is connected to the water inlet of a closed water sample collection bucket 8 via a water outlet pipe 19. A sampling pipe 9 is connected to the outlet of the water sample collection bucket 8. A secondary filtration device is installed inside the water sample collection bucket 8. A flow regulating valve 10 and a flow meter 11 are installed on the sampling pipe 9. A pipe connector 12 is installed at the end of the sampling pipe 9. The pipe connector 12 can be connected to a burette for VOCs detection or to a parallel sampling pipe for parallel sampling.

[0034] In this embodiment, the elastic tensioning mechanism 6 includes a base 61, a mounting base 62 fixedly mounted on the base 61, a central shaft 63 mounted on the mounting base 62, a take-up and untake-up reel 64 rotatably mounted on the central shaft 63, an elastic locking structure for elastically locking the take-up and untake-up reel 64, and an operating handle 65 fixedly mounted on the take-up and untake-up reel 64. The elastic locking structure includes a first spring 66 sleeved on the central shaft 63 and located outside the take-up and untake-up reel 64, and a locking nut 67 rotatably mounted on the central shaft 63 to press the first spring 66.

[0035] The mounting base 62 is provided with a mounting slot 621, and the base 61 is provided with a top panel 611. The mounting slot 621 is engaged with the top panel 611. A locking screw 68 is installed on the groove wall of the mounting slot 621. A pressing block 610 is provided at the lower end of the locking screw 68, and an operating lever 69 is provided at the upper end of the locking screw 68.

[0036] In this embodiment, the length measuring device includes an upper pressure wheel 13 and a lower pressure wheel 14 rotatably mounted on a base 61. A through gap is provided between the upper pressure wheel 13 and the lower pressure wheel 14, through which the traction rope 7 passes and is squeezed by the upper pressure wheel 13 and the lower pressure wheel 14. The upper pressure wheel 13 or the lower pressure wheel 14 is connected to a pulse encoder 17. The lower pressure wheel 14 is rotatably mounted on a lower wheel seat 16, which is fixed on the base 61. The upper pressure wheel 13 is rotatably mounted on an upper wheel seat 15, which is vertically slidably mounted on the base 61 via a vertical guide rod. A second spring 18 is fitted on the vertical guide rod, and the elastic force of the second spring 18 forces the upper pressure wheel 13 and the lower pressure wheel 14 to cooperate with each other. The upper wheel seat 15 is a rectangular seat with the opening facing downwards. The upper pressing wheel 13 is rotatably mounted between the left side wall 151 and the right side wall 152 of the upper wheel seat 15. The lower part of the left side wall 151 and the right side wall 152 is lower than the lower end of the upper and lower pressing wheels 14. The upper end of the lower pressing wheel 14 extends into the range of the left side wall 151 and the right side wall 152 and cooperates with the upper pressing wheel 13.

[0037] The sediment filtration device 5 includes a sediment filter cover that is wrapped around the inlet of the submersible pump 1 and fixed with fasteners. The sediment filter cover has several filter holes. The water sample collection tank 8 includes a tank body 81 and a tank cover 82. The tank cover 82 is detachably fixed to the tank body 81. The secondary filtration device includes a hollow filter cylinder 83, which is installed inside the tank body 81. A support frame 84 is provided inside the tank body 81 to support the filter cylinder 83 from the outside. The inlet and outlet are both located at the upper end of the tank body 81. An inlet pipe 85 is provided inside the tank body 81. One end of the inlet pipe 85 is connected to the inlet, and the other end extends into the interior of the filter cylinder 83. The outlet is connected to the external space of the filter cylinder 83.

[0038] In use, the inflatable airbag 3 and the submersible pump 1 are placed into the water in the groundwater well 4. First, the water in the groundwater well 4 is drawn by the submersible pump 1, and the sediment filtration device 5 filters it once. Then, it enters the internal space of the filter cartridge 83 of the barrel 81 of the water sample collection bucket 8 through the outlet pipe 19. After secondary filtration through the filter cartridge 83, the groundwater enters the external space of the filter cartridge 83 and finally flows into the sampling pipe 9 from the outlet. The end of the sampling pipe 9 is equipped with a pipe connector 12. The pipe connector 12 can be connected to a burette for VOCs detection or to a parallel sampling tube for parallel sampling.

[0039] During sampling, the submersible pump 1 is suspended by the buoyancy of the airbag 3. A suitable length of suspension connector 2 is selected to ensure that the sampling port of the submersible pump 1 is always 0.5m below the water level. One end of the airbag 3 is fixedly connected to the traction rope 7, and the other end of the traction rope 7 is wound around the elastic tensioning mechanism 6. The elastic tensioning mechanism 6 is equipped with a length measuring device to measure the movement distance of the traction rope 7. Thus, the traction rope 7 is only tensioned by the elastic tensioning mechanism 6. When the water level drops, the airbag 3 will descend, pulling the traction rope 7. The traction rope 7 will overcome the rotational resistance and drive the winding reel 64 to rotate, which facilitates the length measuring device to detect the movement length of the traction rope 7, thereby accurately monitoring the drop in water level and monitoring the water level drop in real time. After sampling is completed, the entire device is lifted out of the well by manually cranking the winding reel 64.

[0040] Definition of VOCs

[0041] Volatile organic compounds (VOCs) are a collective term for organic compounds that are easily volatile at room temperature. According to the World Health Organization (WHO), their boiling points range from 50°C to 260°C. Chinese standards further clarify that VOCs refer to "organic compounds that can participate in atmospheric photochemical reactions," including non-methane hydrocarbons (such as alkanes and alkenes), oxygen-containing organic compounds (such as aldehydes and ketones), and chlorine / nitrogen / sulfur-containing organic compounds.

[0042] The pneumatic system, servo motor and other actuators, gear transmission mechanism, and lead screw and nut mechanism mentioned in this embodiment are all current conventional technologies. The 5th edition of the "Mechanical Design Handbook" published in Beijing in April 2008 (5th edition, 28th printing) details the specific structure, principle, and other designs of cylinders, motors, and other transmission mechanisms, which are existing technologies with clear and straightforward structures. The 3rd edition of "Modern Practical Pneumatic Technology" SMC training materials published by Machinery Industry Press on August 1, 2008, details vacuum components, gas circuits, and program control, indicating that the pneumatic structure in this embodiment is also existing technology and clear and straightforward. The book "Motor Drive and Speed ​​Regulation" published by Chemical Industry Press on July 1, 2015, also details motor control and limit switches. Therefore, the circuit and pneumatic connections are clear.

[0043] The above-described embodiments are merely preferred embodiments of the present utility model and are not intended to limit the scope of the present utility model. Any modifications and alterations to the technical solution of the present utility model without departing from its design spirit shall fall within the protection scope defined by the claims of the present utility model.

Claims

1. A well-washing and sampling device for groundwater testing, comprising a submersible pump, characterized in that: The upper end of the submersible pump is connected to an airbag via a suspension connector. The airbag floats on the surface of the groundwater well and suspends the submersible pump. A sediment filtration device is installed at the water inlet at the lower end of the submersible pump. An elastic tensioning mechanism is fixed on the ground of the groundwater well. One end of the airbag is fixedly connected to a traction rope, and the other end of the traction rope is wrapped around the elastic tensioning mechanism. A length measuring device for measuring the movement distance of the traction rope is installed on the elastic tensioning mechanism. The water outlet of the submersible pump is connected to the water inlet of a closed water sample collection bucket via an outlet pipe. A sampling pipe is connected to the outlet of the water sample collection bucket. A secondary filtration device is installed inside the water sample collection bucket. A flow regulating valve and a flow meter are installed on the sampling pipe. A pipe joint is installed at the end of the sampling pipe.

2. The well-washing and sampling device for groundwater testing as described in claim 1, characterized in that: The elastic tensioning mechanism includes a base, a mounting seat fixedly mounted on the base, a central shaft provided on the mounting seat, a take-up and untake-up reel rotatably mounted on the central shaft, an elastic locking structure for elastically locking the take-up and untake-up reel on the central shaft, and an operating handle fixedly mounted on the take-up and untake-up reel.

3. The well-washing and sampling device for groundwater testing as described in claim 2, characterized in that: The elastic locking structure includes a first spring fitted on the central shaft and located outside the take-up and unwinding reels, and a locking nut that compresses the first spring is rotatably mounted on the central shaft.

4. The well-washing and sampling device for groundwater testing as described in claim 3, characterized in that: The mounting base is provided with a locking slot, and the machine base is provided with a top panel. The locking slot is locked onto the top panel. A locking screw is installed on the groove wall of the locking slot. A clamping block is provided at the lower end of the locking screw, and an operating rod is provided at the upper end of the locking screw.

5. The well-washing and sampling device for groundwater testing as described in claim 4, characterized in that: The length measuring device includes an upper pressure wheel and a lower pressure wheel rotatably mounted on the base. A through gap is provided between the upper pressure wheel and the lower pressure wheel. The traction rope passes through and is squeezed by the upper pressure wheel and the lower pressure wheel. The upper pressure wheel or the lower pressure wheel is connected to a pulse encoder.

6. The well-washing and sampling device for groundwater testing as described in claim 5, characterized in that: The lower pressing wheel is rotatably mounted on the lower wheel seat, which is fixed on the machine base. The upper pressing wheel is rotatably mounted on the upper wheel seat, which is vertically slidably mounted on the machine base via a vertical guide rod. A second spring is fitted on the vertical guide rod, and the elastic force of the second spring forces the upper pressing wheel and the lower pressing wheel to cooperate with each other.

7. The well-washing and sampling device for groundwater testing as described in claim 6, characterized in that: The upper wheel seat is a rectangular seat with the opening facing downwards. The upper pressing wheel is rotatably mounted between the left and right walls of the upper wheel seat. The lower part of the left and right walls is lower than the lower end of the upper pressing wheel. The upper end of the lower pressing wheel extends into the range of the left and right walls and cooperates with the upper pressing wheel.

8. The well-washing and sampling device for groundwater testing as described in claim 1, characterized in that: The sediment filtration device includes a sediment filter cover that is wrapped around the water inlet at the lower end of the submersible pump and fixed by fasteners, and the sediment filter cover is provided with a number of filter holes.

9. The well-washing and sampling device for groundwater testing as described in claim 1, characterized in that: The water sample collection bucket includes a bucket body and a bucket lid, the bucket lid being detachably fixed to the bucket body. The secondary filtration device includes a hollow filter cartridge, the filter cartridge being installed inside the bucket body. A support frame is provided inside the bucket body to support the filter cartridge from the outside. The inlet and outlet are both located at the upper end of the bucket body. An inlet pipe is provided inside the bucket body, one end of which is connected to the inlet, and the other end extends into the interior of the filter cartridge. The outlet is connected to the external space of the filter cartridge.

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