A device and method for floating liquid taking of supernatant of coagulation sedimentation tank

Abstract

The application discloses a supernatant floating liquid taking device of a coagulation sedimentation tank, which comprises a guide pipe, a floating mechanism and a water suction mechanism. The guide pipe is fixed in the sedimentation tank, the floating mechanism is used for bearing the water suction mechanism and can slide upwards and / or downwards along the guide pipe under the action of external force; the water suction mechanism is fixedly connected with a water pump and is used for sucking the supernatant of the coagulation sedimentation tank and transmitting the supernatant to the water pump. The water suction port of the device is always located in a constant-depth clean water layer below the liquid surface, and the water pump can be started without waiting for the flocculation to settle below the fixed water suction port, so that the residence time of the sedimentation tank is greatly shortened. The water suction port is always located in the clean water layer, and the lower limit block can prevent the water suction port from entering the sludge layer, thereby completely eliminating the risk of sludge being sucked into the subsequent process. The supernatant residual or sludge mis-sucking phenomenon caused by the rising or falling of the sludge interface does not occur, the supernatant recovery rate is improved, and meanwhile, the invalid sludge is avoided from entering the filter press, so that the energy consumption of the filter press is reduced.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, specifically to a floating liquid collection device and method for supernatant from a coagulation sedimentation tank. Background Technology

[0002] Coagulation and sedimentation technology is a key process in wastewater treatment, widely used in the treatment of domestic sewage and industrial wastewater. A conventional coagulation and sedimentation process includes five steps: chemical dosing, stirring, reaction, coagulation, and sedimentation. Its principle is to use mechanical or hydraulic stirring to ensure sufficient contact between the chemicals and the wastewater. Through charge neutralization, colloids are destabilized (coagulation stage), and then, through the adsorption and bridging effect of polymer molecules, settleable flocs are formed (flocculation stage). Finally, suspended particles are aggregated into flocs. These flocs enter a sedimentation tank, where solid-liquid separation is achieved through gravity settling. The supernatant from the sedimentation tank is sent to subsequent processes, while the bottom sludge is transported to a filter press for treatment.

[0003] In existing common coagulation and sedimentation treatment processes, the dosing, stirring, and coagulation processes are all continuous. However, in the sedimentation stage, the suction port of the supernatant extraction pump is usually fixed in the middle of the sedimentation tank based on experience or wastewater test results. This fixed suction port setting has the following two drawbacks: First, pumping can only be started when the flocs in the sedimentation tank settle below the suction port (which usually requires a stay of 2-4 hours), which greatly affects the efficiency of sewage treatment.

[0004] Secondly, the sedimentation rate and settling ratio of wastewater in the sedimentation tank are closely related to the dosage of chemicals added in the upstream stage, the stirring effect, the composition of the wastewater, and the concentration of the wastewater. When the wastewater sedimentation effect is poor at a certain stage, the sludge-clear water interface is located above the fixed suction port, causing the sludge to be pumped into the subsequent process by the supernatant pump, resulting in shock. When the wastewater sedimentation effect is good at a certain stage, the sludge-clear water interface is located below the fixed suction port, which will lead to incomplete supernatant extraction. Some supernatant and bottom sludge will enter the filter press together, increasing the energy consumption of the filter press and reducing its efficiency.

[0005] Therefore, how to provide a liquid extraction device that can automatically adjust the position of the suction port according to changes in liquid level, always extract clear supernatant and avoid sludge from entering is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0006] In order to at least partially solve the problems existing in the prior art, the present invention provides a floating liquid extraction device and method for supernatant from a coagulation sedimentation tank, the technical solution of which is as follows: A floating liquid extraction device for supernatant from a coagulation sedimentation tank includes a guide pipe, a floating mechanism, and a water suction mechanism. The guide pipe is fixed inside the sedimentation tank. The floating mechanism supports the water suction mechanism and can slide upward and / or downward along the guide pipe under external force. The water suction mechanism is fixedly connected to a water pump and is used to extract the supernatant from the coagulation sedimentation tank and transfer the supernatant to the water pump.

[0007] Furthermore, the floating mechanism includes a sleeve, a bearing, a crossbar, and a float component; the sleeve is a hollow cylindrical tube with a top cover, and the top cover of the sleeve has a through hole for installing the bearing; the bearing is sleeved on the outer wall of the guide tube, and under the action of external force, the sleeve can slide up and down along the guide tube through the bearing; the bottom of the outer wall of the sleeve is circumferentially and evenly spaced with crossbars, and the crossbars radiate outward along the central axis of the sleeve, with the float component installed at their free ends.

[0008] Furthermore, the guide tube is provided with an upper limit block and a lower limit block, and the bearing is sleeved between the upper limit block and the lower limit block on the outer wall of the guide tube. Under the action of external force, the sleeve can slide up and down along the guide tube between the upper and lower limit blocks through the bearing.

[0009] Furthermore, annular protective covers are fixed to the top of the sleeve at the upper and lower ends of the bearing, respectively. The protective covers are connected to the sleeve by screws. A 2mm gap is provided between the inner hole of the protective cover and the guide tube, and a brush sealing ring is installed at the gap.

[0010] Furthermore, the water suction mechanism includes an L-shaped suction pipe and a flexible hose; the L-shaped suction pipe is fixedly installed on the outer wall of the sleeve, sandwiched between the crossbars, and detachably connected to the sleeve; the vertical section of the L-shaped suction pipe is fitted against the outer wall of the sleeve, and the length of the vertical section is set so that the suction port at its bottom is submerged below the liquid surface of the sedimentation tank; the opening of the horizontal section of the L-shaped suction pipe is fixedly connected to the flexible hose, and the other end of the flexible hose is fixedly connected to the water pump.

[0011] Furthermore, the length of the vertical section of the L-shaped suction pipe is set such that the length of the suction port at its bottom is ≥15cm below the liquid surface of the sedimentation tank, and a mud and sand protective cover is installed at the suction port.

[0012] Furthermore, the float component is a closed-cell polyethylene float and / or a hollow stainless steel float.

[0013] Based on the above-described floating liquid collection device, the present invention also describes a method for floating liquid collection of supernatant from a coagulation sedimentation tank, comprising the following steps: S1. Vertically fix the guide pipe in the sedimentation tank, and set an upper limit block and a lower limit block on the guide pipe; sleeve the sleeve onto the guide pipe through the bearing, and install a float at the end of the crossbar at the bottom of the sleeve; submerge the suction port of the L-shaped suction pipe below the liquid surface to a set depth. S2, start the water pump. The buoyancy generated by the float causes the sleeve and L-shaped suction pipe to move up and down along the guide pipe as the liquid level rises and falls, and the suction port is always kept at a constant depth below the liquid level. S3. A radar level gauge is installed on the top of the sedimentation tank. When the level is detected to reach the upper limit, the water pump is automatically started after a 5-minute delay. When the level is detected to drop to the level height corresponding to the lower limit block setting, the water pump is automatically stopped.

[0014] Furthermore, it also includes a limit protection step: when the sleeve rises to the upper limit block, the upper limit block prevents the sleeve from moving further upward, preventing the floating mechanism from falling out of the guide tube; when the sleeve falls to the lower limit block, the lower limit block prevents the sleeve from moving further downward, preventing the suction port from entering the sludge layer.

[0015] Furthermore, the depth of the water inlet below the liquid surface is set at 15-25cm, and this depth is adjusted by adjusting the length of the vertical section of the L-shaped water inlet according to the settling performance of the wastewater in the sedimentation tank. Beneficial effects

[0016] 1. The device described in this invention has its suction port always located at a constant depth (e.g., 20 cm) below the liquid surface in the clear water layer, and pumping can be started without waiting for the flocs to settle below the fixed suction port, thus greatly shortening the residence time in the sedimentation tank.

[0017] 2. The suction port is always located in the clear water layer, and the lower limit block can prevent the suction port from entering the sludge layer, completely eliminating the risk of sludge being pumped into subsequent processes and ensuring the stable operation of the entire sewage treatment system.

[0018] 3. It will not cause supernatant residue or accidental sludge extraction due to the rise or fall of the sludge interface, thus improving the supernatant recovery rate and preventing ineffective sludge from entering the filter press, thereby reducing the energy consumption of the filter press.

[0019] 4. It automatically adjusts the height of the water inlet by relying on buoyancy, without the need for external power or sensor control, making it reliable in operation and particularly suitable for sewage treatment scenarios with large fluctuations in liquid level.

[0020] 5. It adopts self-lubricating bearings, which do not require grease and are not afraid of sewage, sludge and dust intrusion. There are no problems of rolling bearing jamming or seal aging, and it can operate without maintenance for a long time.

[0021] 6. This device can be installed in existing sedimentation tanks without changing the original tank structure. The guide pipe can be fixed using the tank wall or top. Both the floating mechanism and the water suction mechanism are made of corrosion-resistant materials, resulting in low manufacturing costs. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the guide tube structure.

[0023] Figure 2 This is a schematic diagram of the installation of the sleeve and the L-shaped suction pipe.

[0024] Figure 3 This is a schematic diagram of the floating mechanism.

[0025] Symbol Explanation

[0026] 101-Guide tube, 102-Upper limit block, 103-Lower limit block; 201-Sleeve, 202-Bearing, 203-Crossbar, 204-Float component; 301-L-shaped suction pipe, 302-flexible hose. Detailed Implementation

[0027] The technical solutions in the embodiments of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are merely some, and not all, of the embodiments of the present invention.

[0028] The following description of at least one exemplary embodiment is merely illustrative and is not intended to limit the invention or its application or use in any way.

[0029] Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this disclosure.

[0030] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0031] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and equipment should be considered part of the specification.

[0032] In all examples shown and discussed herein, any specific value should be interpreted as merely exemplary and not as a limitation; therefore, other examples of exemplary embodiments may have different values.

[0033] Unless otherwise specified, the products or equipment described in the embodiments are all from commercial channels. Example 1

[0034] This embodiment describes a floating liquid collection device for supernatant in a coagulation sedimentation tank, including a guide pipe 101, a floating mechanism, and a water suction mechanism.

[0035] The guide pipe 101 is vertically fixed inside the sedimentation tank, and its lower end is fixed to the bottom of the tank by a pre-embedded part. To ensure that the guide pipe 101 can stand stably in the sedimentation tank and remain stable during operation, its upper end can be fixed to the top of the sedimentation tank by a bracket or other common methods, which will not be described in detail here.

[0036] An upper limit block 102 and a lower limit block 103 are respectively provided in the upper and lower middle parts of the guide tube 101. Both are preferably stainless steel clamps, which can be adjusted and locked along the guide tube 101.

[0037] The floating mechanism includes a sleeve 201, a bearing 202, a crossbar 203, and a float 204.

[0038] Sleeve 201 is a hollow cylindrical tube with a top cover. The top cover of sleeve 201 has a through hole and a certain thickness for fixing and installing bearing 202. That is, the outer wall of bearing 202 is tightly fitted and fixed to the inner wall of the through hole of the top cover, preferably with an interference fit, to ensure that bearing 202 and sleeve 201 move synchronously.

[0039] The bearing 202 is sleeved on the guide tube 101, specifically positioned between the upper limit block 102 and the lower limit block 103. Under the action of external force, the sleeve 201 can slide up and down along the guide tube 101 between the upper and lower limit blocks 103 via the bearing 202.

[0040] Preferably, the upper and lower end faces of the bearing 202 are each provided with annular protective covers. These covers are made of 316L stainless steel sheet and are fixed to the top of the cylindrical tube with screws. A 2mm gap is maintained between the inner hole of the protective cover and the guide tube 101, and a polyurethane brush seal is installed at this gap to prevent sewage splashing and foreign objects from entering the sliding interface. The upper limit block 102 and the lower limit block 103 directly impact the end faces of the protective covers, preventing the impact force from being transmitted to the bearing 202.

[0041] The outer wall of the sleeve 201 is uniformly spaced with crossbars 203 at intervals around its bottom circumference. The crossbars 203 radiate outward along the central axis of the sleeve 201, and a float 204 is installed at its free end. The float 204 is preferably a closed-cell polyethylene float ball, which is used to support the weight of the entire floating mechanism and the water suction mechanism. Under the action of buoyancy, the sleeve 201 slides up and down on the guide tube 101 as the liquid level in the sedimentation tank changes.

[0042] The water suction mechanism includes an L-shaped water suction pipe 301 and a flexible hose 302.

[0043] The L-shaped suction pipe 301 is made of UPVC material to obtain better mechanical strength. The L-shaped suction pipe 301 is fixedly installed on the outer wall of the sleeve 201 and clamped between the crossbars 203, and can be detachably connected by clamps.

[0044] The vertical section of the L-shaped suction pipe 301 fits against the outer wall of the sleeve 201 and extends 15-25 cm beyond the bottom of the sleeve 201. Obviously, this setting is to ensure the water immersion depth of the L-shaped suction pipe 301. In actual operation, this depth can be adjusted according to the needs. The 15-25 cm provided in this embodiment is the preferred data.

[0045] The horizontal section of the L-shaped suction pipe 301 is fixedly connected to a flexible hose 302 via a flange. The other end of the flexible hose 302 is used to be fixedly connected to the supernatant pump.

[0046] A water inlet is fixedly installed at the vertical section opening of the L-shaped water suction pipe 301, and a mud and sand protection cover is installed at the water inlet.

[0047] The operation process of the liquid extraction device described in this embodiment is briefly described below.

[0048] When the liquid level in the sedimentation tank is at the normal water level, the buoyancy of the float 204 causes the entire floating mechanism and the water suction mechanism to float on the liquid surface, the bearing 202 slides freely along the guide tube 101, and the water suction port is located in the clear water layer below the liquid surface.

[0049] Start the supernatant pump. The supernatant enters the supernatant pump sequentially through the suction port, the vertical and horizontal sections of the L-shaped suction pipe 301, and the flexible hose 302, and is then transported to the subsequent processing steps.

[0050] As the liquid level rises, the float 204 rises with the liquid level, causing the cylindrical tube and L-shaped suction pipe 301 to move upwards. The bearing 202 slides upwards along the guide tube 101, and the suction port always maintains a fixed relative distance from the liquid level, for example, 20cm. When the liquid level is too high and the protective cover touches the upper limit block 102, the upper limit block 102 prevents the cylindrical tube from moving further upwards, preventing the floating mechanism from dislodging from the guide tube 101.

[0051] As the liquid level drops, the float 204 descends with the liquid level, and the entire floating mechanism moves downward, while the suction port remains at a fixed relative distance below the liquid level. If, due to abnormal circumstances, such as excessive sludge discharge or cessation of water intake, the liquid level drops to near the sludge layer of the sedimentation tank, the protective cover will touch the lower limit block 103. At this time, the suction port will still be at a safe distance from the upper surface of the sludge layer, for example, 30 cm. The supernatant pump should stop operating, which can be controlled by interlocking the level gauge or manually, to prevent sludge from being pumped out. Example 2

[0052] According to the description in Example 1, this example uses a coagulation sedimentation tank applied to an urban sewage treatment plant with a treatment capacity of 30 m³ / h as an example to further illustrate the use of Example 1.

[0053] The effective water depth of the sedimentation tank is 5.0m, the liquid level fluctuation range is ±0.5m, and the normal height of the sludge layer is 1.2m from the bottom of the tank.

[0054] The guide tube 101 is made of UPVC material, with an outer diameter of 140mm, a wall thickness of 6mm, and a length of 5.5m. The upper limit block 102 of the guide tube 101 is located 0.3m below the top of the pool, and the lower limit block 103 is located 1.8m from the bottom of the pool. This size corresponds to the lowest safe position of the water intake as described below.

[0055] The floating mechanism includes four crossbars 203 and four floats 204.

[0056] The sleeve 201 of the floating mechanism is made of UPVC material, with an outer diameter of 160mm, a wall thickness of 5mm, and a height of 250mm.

[0057] Bearing 202 is made of graphite-filled nylon 66 material and is shaped like a sleeve 201. Its inner diameter is 0.8 mm larger than the outer diameter of the guide tube 101, and its height is 70 mm. The protective cover of bearing 202 is made of 316L stainless steel sheet with a thickness of 1.5 mm. It is fixed to the top of the cylindrical tube with screws. A 2 mm gap is left between the inner hole of the protective cover and the guide tube 101, and a polyurethane brush seal ring is installed at the gap to prevent sewage splashing and foreign objects from entering the sliding interface. The upper limit block 102 and the lower limit block 103 directly impact the end face of the protective cover to prevent the impact force from being transmitted to the bearing 202 body.

[0058] Four crossbars 203 are evenly welded circumferentially to the bottom outer side of the sleeve 201. The crossbars 203 are made of 316L stainless steel round tubes with an outer diameter of 25mm, a wall thickness of 2mm, and a length of 0.6m. Each crossbar 203 has a float 204 fixed to its end. The float 204 is a closed-cell polyethylene float ball with a diameter of 350mm. A single float ball provides about 22kg of buoyancy when fully submerged. The total buoyancy of the four float balls is about 88kg, which is sufficient to support the total weight of the entire floating mechanism and water suction mechanism, calculated to be about 50kg net weight.

[0059] The water suction mechanism includes an L-shaped suction pipe 301 and a flexible hose 302. The L-shaped suction pipe 301 is made of UPVC material, with a nominal diameter of DN100, an outer diameter of 110mm, a wall thickness of 4.2mm, a vertical section length of 350mm, and a horizontal section length of 0.5m.

[0060] The lower end of the vertical section of the L-shaped suction pipe 301 is the suction port, and a flared anti-vortex cover is installed at the suction port. The L-shaped suction pipe 301 is fixed to the side of the sleeve 201 by a stainless steel clamp, located in the gap between the two crossbars 203. The fixing point is about 100mm away from the bottom of the sleeve 201, so that the height of the horizontal section is lower than the bottom surface of the bearing 202, thus avoiding the hose from interfering with the movement of the bearing 202.

[0061] The vertical distance between the suction port of the L-shaped suction pipe 301 and the liquid surface is set to 200mm, which can be achieved by adjusting the length of the vertical section or by replacing the L-shaped pipe with one of different lengths.

[0062] The horizontal end of the L-shaped suction pipe 301 is the outlet, which is connected to the flexible hose 302 via a quick connector. The flexible hose 302 is a PVC steel wire hose with an inner diameter of 102mm, a length of 2.5m, and a bending radius of not less than 300mm. The other end of the flexible hose 302 is connected to the inlet flange of the supernatant pump, which is fixedly installed outside the sedimentation tank. Example 3

[0063] The technical solution of this embodiment is basically the same as that of Embodiment 1, but the bearing 202 installed at the top of the sleeve 201 is adjusted as follows: A ball bearing 202, model 6204-2RS, made of stainless steel and with a rubber seal ring, is fixedly installed at the top of the sleeve 201 to replace the self-lubricating bearing 202. The ball bearing 202 has annular protective covers on its upper and lower ends. The protective covers are made of 316L stainless steel sheet and are fixed to the top of the cylindrical tube with screws. There is a 2mm gap between the inner hole of the protective cover and the guide tube 101, and a rubber lip seal is installed in the gap.

[0064] The upper limit block 102 and the lower limit block 103 directly impact the end face of the protective cover, preventing the impact force from acting directly on the bearing 202. This embodiment is suitable for applications with extremely low requirements for sliding resistance and good maintenance conditions. Example 4

[0065] The technical solution of this embodiment is basically the same as that of Embodiment 1, but adjustments are made to the crossbar 203, float 204 and L-shaped suction pipe 301 installed at the bottom of the sleeve 201, as follows: There are 3 crossbars 203, which are evenly distributed at 120° intervals along the circumference of sleeve 201; The buoy component 204 uses hollow stainless steel floats, each measuring 300mm×300mm×200mm, providing approximately 18kg of buoyancy; The vertical section of the L-shaped suction pipe 301 adopts a telescopic structure, such as inner and outer sleeves + sealing ring, which makes it convenient to adjust the depth of the suction port on site. Example 5

[0066] The technical solution of this embodiment is basically the same as that of Embodiment 1, but the crossbar 203 installed at the bottom of the sleeve 201 is adjusted as follows: To accommodate smaller diameter sedimentation tanks, the crossbars 203 are arranged with alternating long and short sections, for example, two long sections are 0.8m long and two short sections are 0.4m long. The float components 204 are installed at the ends of the long rod and the short rod respectively, and the size or position of the float components 204 is adjusted so that the center of total buoyancy passes through the axis of the sleeve 201 to avoid tilting. Example 6

[0067] This embodiment describes in detail a method for extracting supernatant using the floating liquid extraction device described in any of the foregoing embodiments, specifically including the following steps: S1, the guide pipe 101 is vertically fixed in the sedimentation tank, with its lower end fixed to the bottom of the tank by a pre-embedded part and its upper end fixed to the top of the tank by a bracket.

[0068] Install upper limit block 102 and lower limit block 103 (stainless steel clamps) on the upper and lower parts of the guide pipe 101 respectively. According to the design liquid level fluctuation range and sludge interface height of the sedimentation tank, ensure the lowest safe position of the suction port, adjust the position of upper limit block 102 and lower limit block 103 and lock them.

[0069] Next, the floating mechanism is installed on the guide tube 101: the sleeve 201 (with bearing 202 and protective cover already installed) is fitted into the guide tube 101, so that bearing 202 is positioned between the upper limit block 102 and the lower limit block 103. A float component 204 (closed-cell polyethylene float or hollow stainless steel float) is fixed to the end of the crossbar 203 at the bottom of the sleeve 201, and the number or size of the float components 204 is adjusted according to the required load-bearing weight to ensure that the total buoyancy is greater than the total weight of the floating mechanism and the water suction mechanism.

[0070] Next, the L-shaped suction pipe 301 is fixed to the side of the sleeve 201 with clamps, positioned between the two crossbars 203. The length of the vertical section of the L-shaped suction pipe 301 is adjusted so that its suction port is located at a set depth below the liquid surface (preferably 15-25cm, 20cm in this embodiment). An anti-vortex cover or filter screen is installed at the suction port.

[0071] Finally, connect one end of the flexible hose 302 to the horizontal section outlet of the L-shaped suction pipe 301, and the other end to the inlet of the supernatant pump fixedly installed outside the sedimentation tank. Install a radar level gauge on the top of the sedimentation tank and interlock it with the control system of the supernatant pump. Set the control logic as follows: when the liquid level reaches the upper limit, the supernatant pump will automatically start after a 5-minute delay; when the liquid level drops to the liquid level height corresponding to the set position of the lower limit block 103, the supernatant pump will automatically stop.

[0072] S2, start the supernatant pump. The buoyancy generated by the float 204 causes the entire floating mechanism and suction mechanism to float on the liquid surface, and the bearing 202 slides freely along the guide tube 101. Since the relative distance between the suction port and the liquid surface is fixed by the length of the vertical section of the L-shaped suction pipe 301, the suction port is always located in the clear water layer 20cm below the liquid surface, regardless of changes in the liquid level. The supernatant enters the supernatant pump through the suction port, the L-shaped suction pipe 301, and the flexible hose 302, and is transported to the subsequent processing steps.

[0073] As the liquid level rises, the float 204 rises with the liquid level, causing the sleeve 201 and the L-shaped suction pipe 301 to move upwards. The bearing 202 slides upwards along the guide pipe 101, and the suction port always maintains a relative distance of 20cm from the liquid level. When the liquid level is too high and the protective cover touches the upper limit block 102, the upper limit block 102 prevents the sleeve 201 from moving upwards further, preventing the floating mechanism from dislodging from the guide pipe 101.

[0074] When the liquid level drops, the float 204 drops with the liquid level, and the entire floating mechanism moves downward, while the suction port remains 20cm below the liquid level. If the liquid level drops to near the sludge layer due to abnormal conditions (such as excessive sludge discharge or cessation of water intake), the protective cover will touch the lower limit block 103. At this time, the suction port is still a safe distance (about 30cm) from the upper surface of the sludge layer, and the supernatant pump should stop operating.

[0075] In automatic operation mode (S3), the radar level gauge monitors the liquid level in the sedimentation tank in real time. When the influent flow rate increases and the liquid level rises to the upper limit, the radar level gauge sends a signal to the control system. The control system delays for 5 minutes (to allow the liquid level to stabilize and avoid frequent start-stop cycles) before automatically starting the supernatant pump to begin pumping water. When the liquid level drops to the height corresponding to the set position of the lower limit block 103 (this value is determined based on the setting position of the lower limit block 103), the control system automatically stops the supernatant pump to prevent sludge from being pumped out. The installation position of the lower limit block 103 corresponds to the lowest safe liquid level at the suction port, and the automatic pump stop is achieved by detecting this liquid level value through the radar level gauge.

[0076] S4. When the liquid level rises or falls abnormally and exceeds the interlocking range of the radar level gauge, the upper limit block 102 and the lower limit block 103 provide mechanical limit protection: if the sleeve 201 rises to the upper limit block 102, the upper limit block 102 directly hits the end face of the protective cover, preventing the sleeve 201 from continuing to move upward and avoiding the floating mechanism from falling out of the guide tube 101; if the sleeve 201 falls to the lower limit block 103, the lower limit block 103 directly hits the end face of the protective cover, preventing the sleeve 201 from continuing to move downward and preventing the suction port from entering the sludge layer.

[0077] In all embodiments of the present invention:

[0078] The guide tube 101, sleeve 201, and L-shaped suction tube 301 are preferably made of UPVC, which is corrosion-resistant and lightweight. Obviously, other corrosion-resistant and lightweight materials, such as nylon and ABS plastic, can also be used. The crossbar 203 is made of 316L stainless steel to withstand greater bending stress; Bearing 202 is made of self-lubricating nylon and graphite material, requiring no lubrication and resistant to sewage corrosion; The protective cover and sealing ring are made of stainless steel and polyurethane, which are corrosion resistant; The 204 float component is made of closed-cell polyethylene, which is resistant to sewage corrosion. Flexible hose 302 is a PVC steel wire hose that is resistant to acids and alkalis.

[0079] All components exhibit excellent corrosion resistance in wastewater environments, requiring no additional coating treatment.

[0080] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

Claims

1. A floating liquid collection device for supernatant from a coagulation sedimentation tank, characterized in that, Includes guide tube, floating mechanism, and water suction mechanism; The guide pipe is installed vertically inside the coagulation sedimentation tank; The floating mechanism is used to support the water absorption mechanism and drives the water absorption mechanism to move upward and / or downward along the guide tube under the action of external force; The water suction mechanism is connected to a water pump and is used to suck up the supernatant from the coagulation sedimentation tank.

2. The floating liquid extraction device for supernatant in a coagulation sedimentation tank according to claim 1, characterized in that, The floating mechanism includes a sleeve, bearings, crossbars, and float components; The sleeve is a hollow cylindrical tube with a top cover, and a through hole is opened in the top cover for fixing and installing the bearing; The bearing is sleeved on the outer wall of the guide tube. Under the action of external force, the sleeve moves up and down along the guide tube through the bearing. A crossbar is evenly spaced around the bottom of the outer wall of the sleeve, and the float is installed at the free end of the crossbar.

3. The floating liquid extraction device for supernatant in a coagulation sedimentation tank according to claim 2, characterized in that, An upper limit block and a lower limit block that can move along the guide tube are provided on the outer wall of the guide tube. The bearing is located between the upper limit block and the lower limit block. Under the action of external force, the sleeve moves along the guide tube between the upper limit block and the lower limit block through the bearing.

4. The floating liquid extraction device for supernatant in a coagulation sedimentation tank according to claim 2, characterized in that, Annular protective covers are provided on the upper and lower end faces of the bearing, respectively. A gap is provided between the inner hole of the protective cover and the guide tube, and a brush sealing ring is provided in the gap.

5. A floating liquid extraction device for supernatant from a coagulation sedimentation tank according to claim 2, characterized in that, The water suction mechanism includes an L-shaped water suction tube and a flexible hose; The L-shaped suction pipe is installed on the outer wall of the sleeve, sandwiched between any set of adjacent crossbars, and is detachably connected to the sleeve, allowing its position to be adjusted along the outer wall of the sleeve. The vertical section of the L-shaped suction pipe is fitted to the outer wall of the sleeve, and the length of the vertical section is set so that the suction port at the bottom is submerged below the clear water layer of the coagulation sedimentation tank. A flexible hose is fixedly connected to the opening of the horizontal section of the L-shaped water suction pipe, and the other end of the flexible hose is fixedly connected to the water pump.

6. The floating liquid extraction device for supernatant in a coagulation sedimentation tank according to claim 5, characterized in that, The distance between the suction port of the L-shaped suction pipe and the surface of the clear water layer is ≥15cm, and a mud and sand protection cover is installed at the suction port.

7. The floating liquid extraction device for supernatant in a coagulation sedimentation tank according to claim 2, characterized in that, The buoy is a closed-cell polyethylene buoy and / or a hollow stainless steel buoy.

8. A method for floating and extracting supernatant from a coagulation sedimentation tank, characterized in that, Includes the following steps: S1. Vertically fix the guide pipe in the sedimentation tank, and set an upper limit block and a lower limit block on the guide pipe; sleeve the sleeve onto the guide pipe through the bearing, and install a float at the end of the crossbar at the bottom of the sleeve; submerge the suction port of the L-shaped suction pipe below the liquid surface to a set depth. S2, start the water pump. The buoyancy generated by the float causes the sleeve and L-shaped suction pipe to move up and down along the guide pipe as the liquid level rises and falls, and the suction port is always kept at a constant depth below the liquid level. S3. A radar level gauge is installed on the top of the sedimentation tank. When the level is detected to reach the upper limit, the water pump is automatically started after a 5-minute delay. When the level is detected to drop to the level height corresponding to the lower limit block setting, the water pump is automatically stopped.

9. A method for floating and extracting supernatant from a coagulation sedimentation tank according to claim 8, characterized in that, It also includes a limit protection step: when the sleeve rises to the upper limit block, the upper limit block prevents the sleeve from moving further upward, preventing the floating mechanism from falling out of the guide tube; when the sleeve falls to the lower limit block, the lower limit block prevents the sleeve from moving further downward, preventing the suction port from entering the sludge layer.

10. A method for floating and extracting supernatant from a coagulation sedimentation tank according to claim 8 or 9, characterized in that, The set depth of the water inlet below the liquid surface is 15-25cm, and this depth is adjusted by adjusting the length of the vertical section of the L-shaped water inlet according to the settling performance of the wastewater in the sedimentation tank.

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