biogas slurry mixing system

Abstract

This invention relates to the field of biogas engineering equipment technology. The invention addresses the problems of sediment accumulation in existing biogas slurry ponds, which affects pond volume and requires periodic cleaning. During cleaning, mechanical entry into the pond can easily damage the impermeable bottom and top membranes. Furthermore, the large surface area of ​​the pond limits the working distance of conventional fixed cleaning devices, making them unsuitable for large-area biogas slurry ponds. This invention includes a navigation platform and a stirring device. The main structure of the navigation platform is submerged below the surface of the biogas slurry pond, with a spherical transparent cover at the top of the platform protruding above the pond surface. A side thruster is installed at the front end of the main structure of the navigation platform, and a main thruster is installed at the rear end. The main thruster provides forward thrust to the navigation platform, and the side thrusters adjust the platform's heading. This invention is used for sediment removal in biogas slurry ponds.

Description

Technical Field

[0001] This invention relates to the field of biogas engineering equipment technology, specifically to a biogas slurry tank mixing system. Background Technology

[0002] A biogas slurry pond is a storage tank for liquid manure. The stored liquid may be biogas slurry that has undergone anaerobic fermentation, or it may be manure liquid that has not undergone anaerobic fermentation. The main components of pasture manure are cow dung, cow urine, cooling spray water, bedding material (mainly solid fibers from solid-liquid separation of manure), milking equipment cleaning water, and domestic sewage. Liquid manure is the liquid portion of pasture manure after solid-liquid separation. It can be categorized into anaerobic and non-anaerobic fermentation types based on the processing method. Unfermented liquid manure, stored in a covered biogas slurry pond, is equivalent to an anaerobic fermentation tank at ambient temperature. It produces biogas containing hydrogen sulfide gas at a concentration of approximately 3000 mg / L.

[0003] Currently, biogas digesters are all built on the ground, with an HPDE geomembrane lining the bottom. For digesters requiring a sealed environment, an additional HPDE top membrane is added to prevent odors and collect gases. Due to prolonged storage, particulate matter in liquid manure and other waste will slowly settle and accumulate at the bottom of the digester. Unfermented liquid manure will settle and stratify within half an hour of entering the digester; after fermentation, clear stratification will occur within one or two days, eventually resulting in distinct sedimentation and clear liquid separation. Because the digester surface area is large and the sediment has poor flowability, the pumps primarily pump out clear liquid during discharge, while sediment gradually accumulates, reducing the effective storage volume. Generally, the effective storage volume of the digester will shrink by 50%-80% every 3-5 years. Therefore, biogas digesters require periodic cleaning. Cleaning requires machinery to enter the digester, which can easily damage the geomembrane and top membrane. Furthermore, the large surface area of ​​the digester limits the operating distance of conventional fixed cleaning devices, making them unsuitable for large-area digesters. Summary of the Invention

[0004] The purpose of this invention is to solve the problems in the prior art, such as the accumulation of sediment in biogas slurry ponds, which affects the pond volume and requires periodic cleaning. During cleaning, mechanical entry into the pond can easily damage the bottom and top membranes. At the same time, the pond area is large, and conventional fixed cleaning devices have limited operating distances and cannot be adapted to large-area biogas slurry ponds. Therefore, this invention provides a biogas slurry pond stirring system.

[0005] The technical solution adopted by the present invention to solve the above problems is as follows: a biogas slurry tank stirring system, including a navigation platform and a stirring device; the main structure of the navigation platform can be submerged below the surface of the biogas slurry tank, and the spherical transparent cover at the top of the navigation platform is exposed above the surface of the biogas slurry tank; a side thruster is installed at the front end of the main structure of the navigation platform, and a main thruster is installed at the rear end; the main thruster is used to provide forward thrust for the navigation platform, and the side thruster is used to adjust the course of the navigation platform; the stirring device includes a smooth arc-shaped protective shell that prevents damage to the biogas slurry tank membrane and an agitating actuator disposed inside the protective shell; the navigation platform and the stirring device are connected by a traction member, and the navigation platform can navigate autonomously in the biogas slurry tank; the stirring device is moved at the bottom of the biogas slurry tank by being towed by the traction member, so that the smooth arc-shaped protective shell slides into contact with the sediment and / or the impermeable membrane at the bottom of the biogas slurry tank; or the stirring device is suspended near the surface of the sediment by the traction member; the stirring device generates a disturbed flow field on the sediment at the bottom of the tank, thereby stirring the sediment at the bottom of the tank.

[0006] Furthermore, the main structure includes a top cover plate and a navigation platform hull. A battery is installed inside the navigation platform hull, and both the side thrusters and the main thruster are connected to the outside of the navigation platform hull. The propulsion directions of the side thrusters and the main thrusters are perpendicular to each other.

[0007] Furthermore, a quick-opening housing is provided in the middle of the top cover, and a spherical transparent cover is provided on each side of the quick-opening housing. A top cover sealing strip is installed between the top cover and the navigation platform shell.

[0008] Furthermore, a quick-opening cover is installed on the top of the quick-opening box, and a vacuum detection port is provided inside the quick-opening box.

[0009] Furthermore, one end of the protective shell is provided with a sediment inlet, and the other end is provided with a drainage balance port; a filter screen is installed on the sediment inlet, and the filter screen covers the outside of the water inlet of the agitator; the protective shell is composed of a left agitator shell and a right agitator shell spliced ​​together, and the overall shape of the agitator shell is streamlined.

[0010] Furthermore, the agitating actuator is a sewage pump, a spiral mixing shaft, or a mixing system.

[0011] Furthermore, the sewage pump is connected to the ribs inside the left and right mixing device housings. The inlet of the sewage pump is located on the filter screen side, and the outlet is connected to a drain pipe that extends to the outside of the protective housing.

[0012] Furthermore, both the top cover and the hull of the navigation platform are made of corrosion-resistant materials.

[0013] Furthermore, both the left and right stirring device housings are made of corrosion-resistant materials.

[0014] Furthermore, the navigation platform also includes a control system installed inside the navigation platform hull. The control system includes a control computer, a control unit, a router, a radio antenna, a GPS module, a motor driver, and a water leakage detection module, all mounted on the control system carrier plate. The control computer is used to store preset paths and generate navigation control commands.

[0015] The control unit, which is connected to the control computer via a data bus, is used to receive navigation control commands issued by the control computer, parse and convert the navigation control commands to generate drive signals, and output the drive signals to the motor driver.

[0016] The motor driver refers to the driver corresponding to the motor in the main thruster and the motor in the side thruster; its input terminal is electrically connected to the output terminal of the control unit, and its output terminal is electrically connected to the main thruster and the side thruster respectively, for receiving the drive signal and controlling the speed and direction of the main thruster and the side thruster respectively according to the drive signal;

[0017] A router that communicates with the control unit via Ethernet;

[0018] A radio antenna electrically connected to the router, the radio antenna and the router being used to enable wireless data interaction between the control unit and the external control terminal;

[0019] The GPS module, whose signal output terminal is connected to the signal input terminal of the control unit, is used to acquire the real-time position information of the navigation platform and transmit the position signal to the control unit;

[0020] The water leakage detection module has its signal output terminal connected to the signal input terminal of the control unit, and is used to detect the water ingress status inside the hull of the navigation platform and transmit the status signal to the control unit.

[0021] The present invention has the following beneficial technical effects:

[0022] The main structure of the navigation platform of this invention is equipped with a side thruster at the front end and a main thruster at the rear end. The navigation platform and the stirring device are connected by a traction rope and a power supply cable. The navigation platform drags the stirring device to stir the sediment at the bottom of the pool. The navigation platform floats in the biogas slurry pool and the depth can be controlled. The two plastic spherical transparent covers on the top are exposed above the liquid surface and will not damage the impermeable bottom membrane and the odor-proof top membrane of the pool.

[0023] The mixing device of this invention has a streamlined structure with a larger outer diameter in the middle and smaller outer diameters at both ends. The sewage pump is installed inside the shell. When the mixing device is dragged at the bottom of the biogas slurry tank, it avoids damage to the bottom membrane of the biogas slurry tank. The streamlined design of the outer shell of the mixing device effectively protects the bottom membrane of the biogas slurry tank.

[0024] This invention's biogas slurry tank mixing system can automatically navigate along a planned route. The navigation platform drives the mixing device to mix simultaneously while navigating, effectively and completely mixing the sediment and the clarified liquid. Centered on the sewage pump, the mixing radius gradually expands, stirring up the sediment and mixing it with the clarified liquid. The sediment is then discharged with the liquid, preventing accumulation within the tank. At other times, a periodic mixing route can be automatically planned to prevent dense sediment buildup, resulting in higher operating and mixing efficiency during discharge. The mixing system shell is made of corrosion-resistant material, adapting to corrosive gas environments and high-concentration particulate matter environments when cleaning thick sediments.

[0025] Through the above technical solution, this invention achieves a complete closed-loop operation of "remote monitoring outside the pool + autonomous patrol inside the pool + anti-scratch membrane", which can efficiently clean the sediment at the bottom of the biogas slurry pool while completely avoiding damage to the HDPE geomembrane and top membrane of the biogas slurry pool by mechanical operations. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the structure of the biogas slurry tank stirring system of the present invention;

[0027] Figure 2 This is a schematic diagram of the structure of an embodiment of the biogas slurry tank stirring system of the present invention;

[0028] Figure 3 This is a schematic diagram of the structure of an embodiment of the stirring device of the present invention;

[0029] Figure 4 This is a schematic diagram of the autonomous operation path planning of the present invention;

[0030] Figure 5 This is an isometric view of the biogas slurry tank stirring system of the present invention;

[0031] Figure 6 This is a front view of the biogas slurry tank stirring system of the present invention;

[0032] Figure 7 This is a left view of the biogas slurry tank stirring system of the present invention;

[0033] Figure 8 This is a schematic diagram of the internal structure of the navigation platform;

[0034] Figure 9 It is a top view of the navigation platform;

[0035] Figure 10 This is a diagram of the electrical modules of the navigation platform control system;

[0036] Figure 11 This is a schematic diagram of the stirring device;

[0037] Figure 12 This is a schematic diagram of the internal structure of the stirring device;

[0038] Figure 13 This is the control principle diagram of the navigation platform control system;

[0039] Figure 14 This is a control signal diagram of the present invention;

[0040] Figure 15 This is the control logic diagram of the present invention;

[0041] Figure 16 This is the task planning logic diagram of the present invention;

[0042] Figure 17 This is a diagram of the physical communication connection of the present invention;

[0043] Figure 18 This is an electrical system connection diagram of the present invention;

[0044] In the diagram: 1. Biogas slurry tank; 2. Top membrane; 3. Impermeable bottom membrane; 4. Mixing system; 5. Navigation platform; 6. Mixing device; 7. Traction component; 8. Top cover plate; 9. Top cover plate sealing strip; 10. Navigation platform shell; 11. Spherical transparent cover; 12. Quick-opening box cover plate; 13. Waterproof cover; 14. Main thruster; 15. Side thruster; 16. Battery; 17. Control system; 18. Control system carrier plate; 19. Left mixing device shell; 20. Right mixing device shell; 21. Filter screen; 22. Sediment inlet; 23. Drainage balance port; 24. Sewage pump; 25. Drainage pipe; 26. Quick-opening box; 27. Vacuum detection port; 28. Cable; 29. ​​Lifting ring. Detailed Implementation

[0045] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. The specific embodiments described herein are only for explaining the invention and are not intended to limit the invention.

[0046] Specific implementation method one: Combining Figures 1 to 12This embodiment describes a biogas slurry tank 1 constructed on the ground, with an HPDE geomembrane 3 laid at the bottom. For tanks requiring sealing, an additional HPDE top membrane 2 is added to prevent odors and collect gases. The biogas slurry tank 1 is equipped with an inlet pipe, and the discharge method includes a self-priming sewage pump and an outlet tank. The outlet tank method involves constructing a concrete vertical shaft connected to the tank wall, with a submersible sewage pump installed inside. Due to prolonged storage, particulate matter in the liquid manure will slowly settle and accumulate at the bottom of the biogas slurry tank. Unfermented liquid manure entering the biogas slurry tank will settle and stratify within half an hour; after fermentation, the biogas slurry entering the tank will exhibit clear stratification after a short-circuit time. Ultimately, both liquid manure and clear liquid will show obvious sedimentation and stratification within the biogas slurry tank. Because the biogas slurry has a large surface area and the sediment has poor fluidity, the sewage pump mainly pumps out the clear liquid during discharge, while the sediment gradually accumulates, occupying the effective storage volume of the tank. Therefore, biogas slurry ponds need to be cleaned periodically. During cleaning, machinery needs to enter the pond, which can easily damage the bottom and top membranes. The pond area is large, and conventional fixed cleaning devices have limited operating distances and cannot be adapted to large-area biogas slurry ponds.

[0047] In this embodiment, the mixing system 4 for solid-liquid mixing in the biogas slurry pond includes a navigation platform 5 and a mixing device 6. The navigation platform 5 is a submersible buoyancy structure, and its main structure can be submerged below the surface of the biogas slurry pond, with the spherical transparent cover 11 at the upper end of the navigation platform 5 protruding from the surface of the biogas slurry pond. A side thruster 15 is installed at the front end of the main structure of the navigation platform 5, and a main thruster 14 is installed at the rear end. The main thruster 14 is used to provide forward thrust for the navigation platform, and the side thruster 15 is used to adjust the course of the navigation platform. The mixing device 6 includes a smooth arc-shaped protective shell to prevent damage to the biogas slurry pond membrane and an agitator disposed inside the protective shell.

[0048] The navigation platform 5 and the stirring device 6 are connected by a traction member 7. The navigation platform 5 can navigate autonomously in the biogas slurry tank 1. The stirring device 6 is towed by the traction member 7 to move at the bottom of the biogas slurry tank, so that the smooth arc-shaped protective shell slides into contact with the sediment and / or impermeable membrane at the bottom of the biogas slurry tank. Alternatively, the stirring device 6 can be suspended near the surface of the sediment by the traction member 7. The stirring device 6 generates a disturbed flow field on the sediment at the bottom of the tank, thereby stirring the sediment at the bottom of the tank.

[0049] In a preferred embodiment, the main structure includes a top cover plate 8 and a navigation platform housing 10. A battery 16 is disposed inside the navigation platform housing 10, and side thrusters 15 and main thrusters 14 are both connected to the outside of the navigation platform housing 10. The thrusting directions of the side thrusters 15 and the main thrusters 14 are perpendicular to each other.

[0050] In a preferred embodiment, a quick-opening housing 26 is provided in the middle of the top cover plate 8, and a spherical transparent cover 11 is provided on each side of the quick-opening housing 26. A top cover sealing strip 9 is installed between the top cover plate 8 and the navigation platform shell 10.

[0051] In a preferred embodiment, a quick-opening cover plate 12 is installed on the top of the quick-opening housing 26, and a vacuum detection port 27, a power-on plug and a charging connector are provided inside the quick-opening housing 26.

[0052] In a preferred embodiment, a sediment inlet 22 is provided at one end of the protective housing, and a drainage balance port 23 is provided at the other end; a filter screen 21 is installed on the sediment inlet 22, and the filter screen 21 covers the outside of the water inlet of the agitator; the protective housing is composed of a left agitator housing 19 and a right agitator housing 20 spliced ​​together, the overall shape of the agitator housing is streamlined, and the agitator is a sewage pump 24, a spiral agitator shaft or an agitator system.

[0053] In a preferred embodiment, the sewage pump 24 is connected to the ribs inside the left mixing device housing 19 and the right mixing device housing 20. The inlet of the sewage pump 24 is located on the side of the filter screen 21, and the outlet is connected to a drain pipe 25, which extends to the outside of the protective housing. The traction component 7 between the navigation platform 5 and the mixing device 6 is provided with at least two traction ropes, traction chains, etc. The traction component 7 is wrapped with a flexible protective layer. The traction ropes are connected to the two end faces of the left mixing device housing 19 and the right mixing device housing 20, effectively stabilizing the overall position of the mixing device 6 in the biogas slurry tank 1.

[0054] In a preferred embodiment, both the top cover 8 and the platform hull 10 are made of corrosion-resistant materials, preferably 316L stainless steel or carbon fiber.

[0055] In a preferred embodiment, both the left stirring device housing 19 and the right stirring device housing 20 are made of corrosion-resistant materials, preferably 316L stainless steel or carbon fiber.

[0056] In a preferred embodiment, the navigation platform 5 includes a control system 17 installed inside the navigation platform housing 10. The control system 17 includes a control computer, a control unit, a router, a radio antenna, a GPS module, a motor driver, and a water leakage detection module disposed on a control system carrier board 18. The control computer and the control unit are connected, and the control unit is connected to the router, the radio antenna, the GPS module, the motor driver, and the water leakage detection module, respectively.

[0057] A control computer, used to store preset paths and generate navigation control commands;

[0058] The control unit, which is connected to the control computer via a data bus, is used to receive navigation control commands issued by the control computer, parse and convert the navigation control commands to generate drive signals, and output the drive signals to the motor driver.

[0059] The motor driver refers to the driver corresponding to the motor in the main thruster 14 and the motor in the side thruster 15; its input terminal is electrically connected to the output terminal of the control unit, and its output terminal is electrically connected to the main thruster 14 and the side thruster 15 respectively, for receiving the drive signal and controlling the speed and direction of the main thruster 14 and the side thruster 15 respectively according to the drive signal;

[0060] A router that communicates with the control unit via Ethernet;

[0061] A radio antenna electrically connected to the router, the radio antenna and the router being used to enable wireless data interaction between the control unit and the external control terminal;

[0062] The GPS module, whose signal output terminal is connected to the signal input terminal of the control unit, is used to acquire the real-time position information of the navigation platform and transmit the position signal to the control unit;

[0063] The water leakage detection module has its signal output terminal connected to the signal input terminal of the control unit, and is used to detect the water ingress status inside the navigation platform hull 10 and transmit the status signal to the control unit.

[0064] In this embodiment, the main structure of the solid-liquid mixing system navigation platform 5 consists of a top cover plate 8, a sealing strip, and a navigation platform shell 10. The shell contains a battery 16 and a control system 17. The top of the shell is provided with a spherical transparent cover 11 and a quick-opening box 26. A propeller is installed on the outside of the shell. The shell serves as a load-bearing device and a seal. The battery 16 inside the shell provides energy for the mixing system.

[0065] The control system 17 includes a control board, a radio module, a GPS signal module, and a leak detection module. The control board is used for signal processing and power distribution. The radio module and GPS signal module are located directly below the spherical transparent cover 11. The platform shell 10 is made of 316L stainless steel, which is not easily transmissible to signals. The plastic spherical transparent cover 11 can effectively transmit radio waves and GPS signals. The radio antenna and GPS module take advantage of the wave-transmitting function of the spherical transparent cover 11, allowing signals to pass through without penetrating water or the top membrane. The leak detection module detects whether water has entered the shell. The quick-opening housing 26 has a vacuum detection port 27 inside, which detects the airtightness of the platform shell. The main thruster 14 provides propulsion power to the platform, and the side thrusters 15 provide steering power. The stirring device 6 stirs the solid-liquid mixture, causing the nearby liquid to flow and causing the sediment at the bottom of the pool to float and mix with the clear liquid on the top of the biogas slurry pool. (Refer to...) Figures 1-3 The navigation platform 5 floats in the biogas slurry pool under buoyancy equal to its own weight and is autonomously submerged under control. Two spherical transparent covers 11 protrude above the liquid surface; the buoyancy principle is existing technology. The stirring device 6 of the solid-liquid mixing system 4 has two operating modes. Figure 1 To ensure the normal thickness of the sediment in the biogas slurry pond, the drain pipe 25 of the mixing device 6 extends from the drain hole in the middle of the mixing device housing. The drain pipe 25 faces upwards, causing the sediment to float and mix with the clear liquid on the surface of the biogas slurry pond. Initially, the mixing device 6 sinks to the bottom of the biogas slurry pond, and the navigation platform 5 tows the mixing device 6. After the mixing system 4 automatically navigates and cleans the biogas slurry pond several times, the sediment layer at the bottom gradually decreases. Figure 2 The stirring device 6 shown is adjusted from a horizontal position to a vertical position, and the navigation platform 5 suspends the stirring device 6 for operation. The stirring device 6 is about 10 cm above the bottom of the pool, and the sediment is disturbed by a submersible pump. Another operating mode of the stirring device 6 is as follows: Figure 3 As shown, when the sediment in the biogas slurry pond is thick, the impact force of the drain pipe of the sewage pump 24 is usually stronger than the suction force of the inlet. The drain pipe 25 of the stirring device 6 extends from the drain balance port 23 of the shell and drains water downwards. The sediment is cleaned by the combined impact force of the drain pipe 25 and the suction disturbance of the sewage pump 24.

[0066] Specific Implementation Method Two: Combining Figures 1 to 12 In this embodiment, a side thruster 15 is installed at the front end of the main structure of the navigation platform 5, and a main thruster 14 is installed at the rear end. A battery 16 is installed inside the main structure. The navigation platform 5 and the stirring device 6 are connected by a traction component 7 and a cable 28. The navigation platform 5 supplies power to the stirring device 6 through the cable 28. The navigation platform 5 can autonomously navigate or be remotely controlled in the biogas slurry pool 1. The navigation platform 5 drags the stirring device 6 to stir the sediment deposited at the bottom of the pool.

[0067] In a preferred embodiment, a quick-opening housing 26 is provided in the middle of the top cover plate 8 of the navigation platform 5. A spherical transparent cover 11 is provided on each side of the quick-opening housing 26. A top cover sealing strip 9 is installed between the top cover plate 8 and the navigation platform shell 10, and a sealing strip is also provided between the spherical transparent cover 11 and the top cover plate 8. The main structural shell of the navigation platform 5 remains sealed and leak-proof. A transparent plastic quick-opening housing cover 12 is installed on the top of the quick-opening housing 26. The quick-opening housing 26 contains a vacuum detection port 27, a power-on plug, and a charging connector, etc. A waterproof cover 13 is provided between the quick-opening housing 26 and the top cover plate 8.

[0068] In this embodiment, the solid-liquid mixing system's navigation platform 5 can automatically operate along a planned route, driving the mixing device 6 to mix while navigating, effectively and completely mixing the sediment and the clarified liquid. When the solid-liquid mixing system is working, the top spherical transparent cover 11 is positioned above the liquid surface, while the rest is submerged in the biogas slurry. The mixing system can control the depth, preventing damage to the impermeable bottom membrane 3 and the odor-proof top membrane 2. For cleaning operations where the biogas slurry tank has the odor-proof top membrane 2, a portion of the membrane must first be lifted, the mixing system placed into the biogas slurry tank, and then the odor-proof top membrane 2 replaced. The solid-liquid mixing system's navigation platform 5 can adapt to a minimum liquid depth of 1-1.5m and a maximum of 5m. The system is battery-powered for convenient operation. The main structure of the navigation platform 5 is made of corrosion-resistant materials, adapting to corrosive gas environments and high-concentration particulate matter environments when cleaning tanks with thick sediment.

[0069] Sediment accumulation occurs in biogas slurry ponds due to their large surface area and poor fluidity. While sedimentation is prevented only around the external sand discharge pump, it accumulates in most areas, affecting the effective volume. The fixed stirring distance is limited, making it unsuitable for large ponds. A solid-liquid mixing system can automatically move and stir to adapt to the biogas slurry pond structure. During discharge pump operation, the stirring radius gradually expands from the pump, stirring up the sediment and mixing it with the clarified liquid. The sediment is then discharged with the liquid, preventing further accumulation. At other times, the system can automatically plan periodic stirring routes to prevent dense sedimentation and achieve higher operating and mixing efficiency during discharge stirring.

[0070] The other components and connections are the same as in Specific Implementation Method 1.

[0071] Specific implementation method three: Combining Figures 1 to 12This embodiment describes a stirring device 6 comprising a protective housing and an agitator disposed within the protective housing. One end of the protective housing has a sediment inlet 22, and the other end has a drainage balance outlet 23. A filter screen 21 is installed on the sediment inlet 22, covering the outside of the inlet of the agitator. The protective housing is composed of a left stirring device housing 19 and a right stirring device housing 20, and the overall shape of the stirring device housing is streamlined. A sewage pump 24 is connected to the ribs inside the left stirring device housing 19 and the right stirring device housing 20. The inlet of the sewage pump 24 is located on the side of the filter screen 21, and the outlet is connected to a drain pipe 25, which extends to the outside of the stirring device housing. During the cleaning operation of the biogas slurry pond, the sediment and biogas slurry at the bottom of the pond enter the sewage pump 24 through the sediment inlet 22 and are discharged through the drain pipe 25. The centrifugal force of the sewage pump impeller causes the nearby liquid to flow, thereby causing the sediment to float and mix with the clear liquid on the upper layer of the biogas slurry pond. The sewage discharge unit preferably adopts a submersible pump, a spiral stirring shaft or a stirrer.

[0072] In this embodiment, the mixing device 6 is a bottom-mounted mixing system. One end of the mixing device shell has a sediment inlet 22, and the other end has a drainage balance port 23. Semi-circular notches are machined into the internal ribs of the left mixing device shell 19 and the right mixing device shell 20. These structures, including the drainage balance port 23 and the notches on the shell ribs, prevent air from accumulating inside the mixing device shell as it sinks to the bottom of the biogas slurry tank. The mixing device shell is filled with biogas slurry, allowing it to sink smoothly to the bottom and thoroughly mix the deposited muddy material with the liquid. The internal sewage pump 24 of the mixing device 6 is equipped with anti-tangling pulverizing blades, which automatically cut long-fiber impurities such as forage while efficiently mixing. Furthermore, the outer shell of the mixing device 6 adopts a smooth, streamlined saddle-shaped design, effectively protecting the HPDE geomembrane at the bottom of the biogas slurry tank.

[0073] The other components and connections are the same as in Specific Implementation Method 1.

[0074] Specific implementation method four: Combination Figures 13 to 18 This embodiment describes a navigation platform 5 with high-precision navigation and fully autonomous operation planning capabilities. It can automatically generate a fully covered travel path based on the shape of the pool, achieving unmanned closed-loop operation under standard conditions. The system is equipped with intelligent dwell logic, relying on single-beam acoustic and optical sensors to construct a real-time multi-dimensional sensing system, enabling real-time monitoring of the water's condition. The system can automatically calculate the optimal dwell time based on the degree of solid-liquid mixing at each location.

[0075] The system boasts high reliability and maintainability, equipped with a power redundancy system. Even in extreme abnormal situations, operators can still take over control via manual emergency mode to ensure the safe return of the navigation platform. For extreme cases such as power system failure, the top of the solid-liquid mixing system navigation platform 5 is equipped with lifting devices such as lifting rings 29 for rapid evacuation from the site. Furthermore, the system has a built-in intelligent power monitoring and management module. When the power level falls below a safe threshold, the system will automatically trigger a low-power return, enabling the platform to autonomously return to port. Figures 11-15 Description of the control section of navigation platform 5:

[0076] 4.1 Overall Control Process

[0077] This system adopts a dual-channel redundant control architecture to ensure the execution of work instructions under normal operating conditions and the safety redundancy under extreme operating conditions. In standard operating mode, instructions are issued through the regular operation link; under extreme operating conditions, to ensure the safety of the system in complex environments, an independent redundant control channel is designed in the architecture.

[0078] The ground station serves as the top-level window for human-machine interaction, responsible for formulating global operational strategies and transmitting macro-level task instructions to the onboard processing system of the underwater system via wireless links.

[0079] After receiving the task, the onboard processing system performs path planning and logical calculations, transforming the macro-level task into specific automatic task instructions, which are then sent to the embedded control core in real time.

[0080] The embedded control core, acting as the underlying execution unit, drives the propulsion system and hybrid operation system based on received instructions and information from the positioning system and energy management system. Simultaneously, the control core transmits real-time status feedback information from each module back to the upper layer, forming a closed-loop control system.

[0081] The handheld remote control terminal has the highest priority intervention capability, can send emergency commands, and take over the power and work load, thereby building a control logic of "separation of decision-making and execution, and mutual backup of automatic and manual operation".

[0082] 4.2 System Operation Flow

[0083] After powering on, the system waits for the ground station to send an unlock command and then runs a self-test program. Once communication, positioning, power, and power supply are confirmed to be normal, the system executes the unlock command and switches to automatic mission mode. During operation, the program scans the status in real time: if insufficient power is detected or the mission is completed, it automatically switches to return-to-home mode to return to port autonomously; if communication / positioning is lost, motors are offline, or manual remote control intervention is required, the system will switch to emergency remote control mode, handing over control to manual personnel to ensure safety. After returning to the starting point from return-to-home mode, the system will automatically execute a locking procedure to complete a single cleanup mission.

[0084] 4.3 Path Planning

[0085] The core of the system's path planning is based on accurate environmental perception. The underlying program integrates a high-precision multi-source fusion perception architecture, which collects raw data from RTK+GNSS, IMU (MEMS), and electronic compass in real time. The data is fused through the built-in extended Kalman filter (EKF) algorithm to calculate the vehicle's latitude and longitude coordinates, heading attitude, and speed at the current moment.

[0086] The navigation module uses high-confidence positioning data for path planning. Based on a preset task chain, it calculates the driving trajectory from the "previous task point" to the "next task point" in real time and transmits the path deviation to the control layer.

[0087] The program employs a cascaded closed-loop control strategy: first, the position controller calculates the target speed, and then the attitude controller calculates the platform angle required to maintain the path.

[0088] The final execution command will be fed into the thrust distribution controller. This module, based on the hydrodynamic model of the navigation platform, automatically maps the abstract control torque to the specific speed command of the main motor, ensuring that the navigation platform always performs standardized autonomous operations along the preset path.

[0089] 4.4 Communication Section

[0090] To ensure signal transmission stability, the system employs a multi-link communication network. During routine operations, the system prioritizes using the 4G network to establish a high-bandwidth data channel, ensuring that ground command terminals can receive high-definition video feeds and full monitoring data in real time. To support high-precision operations, the communication network also integrates RTK differential positioning data streams, receiving base station correction signals in real time via a dedicated frequency band, thus providing high-precision navigation support for the system.

[0091] Within the underwater system, a switch connects the onboard processing system and the embedded control core, ensuring reliable information flow within the system. Furthermore, to maintain communication in extreme conditions, the system is equipped with a 915MHz emergency remote control link as backup radio communication, in addition to the main communication network.

[0092] 4.5 Electrical Connections

[0093] The system is powered by a 48V high-capacity power battery pack. A power isolation module is used to isolate the main circuit and the auxiliary circuit to prevent the control signal and the drive current from interfering with each other.

[0094] The main circuit is uniformly allocated by the power management unit (PMU), which provides high current support for the embedded control core and the four-way power propulsion unit, and uses this unit to provide battery status feedback.

[0095] The auxiliary circuit introduces an isolation voltage regulator module to step down and regulate the power supply to two power rails, 12V and 5V, which drive the industrial router, radio communication module and onboard processing system respectively.

[0096] For the high-energy-consuming deep mixing module, the system is designed with independent relays. The onboard computing terminal issues on / off commands according to the operation logic to achieve logical isolation control of high-power loads.

[0097] The other components and connections are the same as in Specific Implementation Method 1.

[0098] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A biogas slurry tank stirring system, characterized in that: It includes a navigation platform (5) and a stirring device (6); the main structure of the navigation platform (5) can be submerged below the surface of the biogas slurry tank, and the spherical transparent cover (11) at the upper end of the navigation platform (5) is exposed above the surface of the biogas slurry tank; a side thruster (15) is installed at the front end of the main structure of the navigation platform (5), and a main thruster (14) is installed at the rear end; the main thruster (14) is used to provide forward thrust for the navigation platform, and the side thruster (15) is used to adjust the course of the navigation platform; The stirring device (6) includes a smooth arc-shaped protective shell that prevents the biogas slurry pond membrane from being damaged and a stirring actuator disposed inside the protective shell; The navigation platform (5) and the stirring device (6) are connected by a traction member (7). The navigation platform (5) can autonomously submerge in the biogas slurry pond (1). The stirring device (6) is towed by the traction member (7) to move at the bottom of the biogas slurry pond, so that the smooth arc-shaped protective shell slides into contact with the sediment and / or impermeable membrane at the bottom of the biogas slurry pond. Alternatively, the stirring device (6) can be suspended near the sediment surface by the traction member (7). The stirring device (6) generates a disturbed flow field on the sediment at the bottom of the pond, thereby stirring the sediment at the bottom of the pond.

2. The biogas slurry tank stirring system according to claim 1, characterized in that: The main structure includes a top cover plate (8) and a navigation platform shell (10). A battery (16) is installed inside the navigation platform shell (10). The side thrusters (15) and the main thrusters (14) are both connected to the outside of the navigation platform shell (10). The thrusting directions of the side thrusters (15) and the main thrusters (14) are perpendicular to each other.

3. The biogas slurry tank stirring system according to claim 2, characterized in that: A quick-opening housing (26) is provided in the middle of the top cover (8), and a spherical transparent cover (11) is provided on both sides of the quick-opening housing (26). A top cover sealing strip (9) is installed between the top cover (8) and the navigation platform shell (10).

4. The biogas slurry tank stirring system according to claim 3, characterized in that: The quick-opening box (26) is equipped with a quick-opening box cover plate (12) on the top, and a vacuum detection port (27) is provided inside the quick-opening box (26).

5. The biogas slurry tank stirring system according to claim 1, characterized in that: One end of the protective shell is provided with a sediment inlet (22), and the other end is provided with a drainage balance port (23). A filter screen (21) is installed on the sediment inlet (22), and the filter screen (21) covers the outside of the water inlet of the agitator; the protective shell is composed of the left agitator shell (19) and the right agitator shell (20), and the overall shape of the agitator shell is streamlined.

6. The biogas slurry tank stirring system according to claim 5, characterized in that: The agitation actuator is a sewage pump (24), a spiral mixing shaft, or a mixer.

7. The biogas slurry tank stirring system according to claim 6, characterized in that: The sewage pump (24) is connected to the ribs inside the left stirring device housing (19) and the right stirring device housing (20). The inlet of the sewage pump (24) is located on the side of the filter screen (21), and the outlet is connected to the drain pipe (25), which extends to the outside of the protective housing.

8. The biogas slurry tank stirring system according to claim 2, characterized in that: Both the top cover (8) and the hull of the navigation platform (10) are made of corrosion-resistant materials.

9. The biogas slurry tank stirring system according to claim 5, characterized in that: Both the left stirring device housing (19) and the right stirring device housing (20) are made of corrosion-resistant materials.

10. The biogas slurry tank stirring system according to claim 1, characterized in that: The navigation platform (5) also includes a control system (17) installed inside the navigation platform housing (10). The control system (17) includes a control computer, control unit, router, radio antenna, GPS module, motor driver and leakage detection module installed on the control system carrier board (18). A control computer, used to store preset paths and generate navigation control commands; The control unit, which is connected to the control computer via a data bus, is used to receive navigation control commands issued by the control computer, parse and convert the navigation control commands to generate drive signals, and output the drive signals to the motor driver. Motor driver, the motor driver refers to the driver corresponding to the motor in the main thruster (14) and the motor in the side thruster (15); Its input terminal is electrically connected to the output terminal of the control unit, and its output terminal is electrically connected to the main thruster (14) and the side thruster (15) respectively, for receiving the drive signal and controlling the rotation speed and direction of the main thruster (14) and the side thruster (15) respectively according to the drive signal; A router that communicates with the control unit via Ethernet; A radio antenna electrically connected to the router, the radio antenna and the router being used to enable wireless data interaction between the control unit and the external control terminal; The GPS module, whose signal output terminal is connected to the signal input terminal of the control unit, is used to acquire the real-time position information of the navigation platform and transmit the position signal to the control unit; The water leakage detection module has its signal output terminal connected to the signal input terminal of the control unit, and is used to detect the water ingress status inside the hull (10) of the navigation platform and transmit the status signal to the control unit.

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