A special dredging device for rural water conservancy river engineering

Abstract

The present application relates to a kind of rural water conservancy river course engineering special dredging device, belong to water conservancy engineering dredging equipment field, including front end shovel suction crushing unit and intermediate conveying unit.The front end shovel suction crushing unit is equipped with shovel bottom plate, cutter box, the cutter box bottom wall is the comb-tooth type grid plate of multiple open hollow grooves, shear cutter roller and tear tooth roller are arranged horizontally and parallel in the cutter box and rotate oppositely, shear cutter roller is installed with blade edge's crescent shear blade, tear tooth roller is installed blunt tear tooth, the lowest rotation track of shear blade and tear tooth is 2mm to 5mm with the clearance of comb-tooth type grid plate upper surface.The intermediate conveying unit includes unblock centrifugal pump and conveying pipeline communicated with collection hopper.The present application is matched with the specific gap of double roller and comb-tooth type grid plate by function differentiation, constructs forced circulation crushing and screening mechanism, completely solves the technical problem of traditional dredging equipment when facing straw, mulching film, fishing net and other easily winding sundries, easy to wind, need frequent shutdown cleaning.

Description

Technical Field

[0001] This invention relates to the field of dredging equipment technology, and in particular to a special dredging device for rural water conservancy and river engineering. Background Technology

[0002] Rural waterways are vital for agricultural irrigation, flood control and drainage, and the rural aquatic ecosystem. Due to the seasonal nature of agricultural production and the lifestyles of rural residents, the sediment in rural waterways often contains a large amount of crop straw, discarded agricultural mulch film, dead branches and leaves, and abandoned fishing nets, in addition to regular silt. Among these debris, straw, dead branches, and fishing nets are fibrous or thread-like, while mulch film is thin. These materials intertwine and entangle with the silt, forming highly resilient and easily entangled composite polluted sediment, posing significant challenges to conventional dredging operations.

[0003] In existing technologies, the most common method for dredging such debris-laden waterways is to use dredging vessels or pumps equipped with cutter suction dredgers. These devices use a high-speed rotating cutter head to cut, agitate, and mix the riverbed sediment with water to form slurry, which is then pumped to an onshore storage yard or treatment site.

[0004] However, the aforementioned existing technologies have the following prominent drawbacks when practically applied to rural waterways: During dredging, debris such as plastic film, fishing nets, and long-fiber straw in rural waterways easily become entangled on the cutter head and its transmission components. Specifically, linear and fibrous materials like fishing nets and straw tightly wrap around the cutter teeth and shaft, while thin films like plastic film stretch and wrap around the cutter head surface under the rotation of the cutter. Once entanglement occurs, the cutter head is tightly bound and jammed by the debris, losing its cutting ability, and the mud pump suction port becomes blocked. At this point, dredging operations must be interrupted, and the entangled material must be removed manually. Because various debris are forcefully stretched and multi-layered under the high-speed rotation of the cutter, and because the cutter head has a complex structure and sharp blades, the cleaning operation is extremely difficult—workers must use knives to cut the fibers and tear the films layer by layer, resulting in a confined operating space, high labor intensity, and a risk of injury from the blades. Cleaning a single entanglement accident can take anywhere from tens of minutes to several hours, causing work interruptions and affecting the project schedule. Rural river dredging has obvious seasonal characteristics, with the best working window concentrated in the short winter and spring dry season. Frequent shutdowns for cleaning often make it difficult to complete the annual dredging plan on time, and a large amount of silt can only be left to be dealt with in the following year, resulting in a passive situation of "cleaning every year and silting every year". Summary of the Invention

[0005] This invention provides a special dredging device for rural water conservancy and river engineering, which can solve the problem that traditional dredging equipment in the prior art is easily entangled with straw, plastic film, fishing nets and other easily tangled debris, requiring frequent shutdowns for manual cleaning.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: a special dredging device for rural water conservancy river engineering, including a front-end shovel and crushing unit and an intermediate conveying unit.

[0007] The front-end shovel-suction crushing unit includes: a shovel bottom plate for sliding along the riverbed and shoveling surface silt; a cutter box located behind the shovel bottom plate, the bottom wall of which is a comb-type grid plate with multiple elongated slots; a shearing roller and a tearing tooth roller rotatably connected inside the cutter box; the shearing roller and the tearing tooth roller are arranged horizontally parallel and rotate in opposite directions; the shearing roller is equipped with crescent-shaped shearing blades with cutting edges; the tearing tooth roller is equipped with tearing teeth with blunt tips; the gap between the lowest rotation trajectory of the shearing blades and tearing teeth and the upper surface of the comb-type grid plate is 2mm to 5mm; and a collection hopper connected to the lower side of the comb-type grid plate for receiving materials falling from the slots.

[0008] The intermediate conveying unit includes a non-clogging centrifugal pump and a conveying pipeline. The suction port of the non-clogging centrifugal pump is connected to the bottom outlet of the collection hopper, and the inlet end of the conveying pipeline is connected to the discharge port of the non-clogging centrifugal pump.

[0009] Preferably, the shearing blade roller and the tearing toothed roller are each connected to a cycloidal hydraulic motor, and the rotational speed ratio between the shearing blade roller and the tearing toothed roller is 2:1 to 5:1. Through differential rotation, the shearing blade actively cuts straw and mulch film using its cutting edge, while the tearing teeth use friction to fix the fishing net and roots for the shearing blade to tear. Because the tearing toothed roller rotates at a lower speed, its tearing teeth have a longer residence time in the biting zone, which can provide a stable reaction force support point for the shearing blade, realizing differentiated and coordinated crushing with "fast cutting and slow tearing".

[0010] Preferably, a hydraulic proportional speed control valve is connected to the inlet or return oil line of the cycloidal hydraulic motor connected to the shearing roller. This valve is used to adjust the rotational speed of the shearing roller. The hydraulic proportional speed control valve can be installed in the oil circuit of the cycloidal hydraulic motor driving the shearing roller. By adjusting the opening of the hydraulic proportional speed control valve, the rotational speed of the shearing roller can be changed, thereby adjusting the speed ratio between the shearing roller and the tearing toothed roller to adapt to the crushing requirements of different materials.

[0011] Preferably, the shearing blades are arranged spirally along the axial direction of the shearing roller, ensuring that there are always shearing blades in a cutting state during the rotation of the shearing roller, resulting in uniform force and minimal vibration. The tearing teeth are arranged in a linear staggered pattern along the axial direction of the tearing tooth roller, meaning that each row of tearing teeth is staggered from each other by a certain distance in the axial direction. This arrangement ensures that, viewed from the circumference of the tearing tooth roller, each row of tearing teeth forms a continuous, staggered coverage in the axial direction, ensuring that no matter where the material is in the axial position within the blade box, there is a corresponding tearing tooth to press and grasp it without any blind spots, thereby improving the crushing efficiency.

[0012] Preferably, a forced feeding wheel is rotatably connected to the bottom outlet of the collection hopper, and the forced feeding wheel is connected to a drive device. When the collection hopper contains a large amount of straw fiber and the material is in a loose, bridging state, the slow agitation of the forced feeding wheel breaks the static friction structure of the material, forcibly pushing the material into the suction port of the non-clogging centrifugal pump, ensuring continuous feeding by the non-clogging centrifugal pump and avoiding cavitation.

[0013] Preferably, the flow channel width of the non-clogging centrifugal pump is greater than or equal to the width of the perforated groove. Due to the screening effect of the comb-type grating, only materials smaller than the width of the perforated groove can fall into the collection hopper and enter the non-clogging centrifugal pump. Since the flow channel width of the non-clogging centrifugal pump is greater than this size, it ensures that all materials passing through the comb-type grating can pass through the non-clogging centrifugal pump without obstruction, thus eliminating the possibility of clogging within the non-clogging centrifugal pump by design.

[0014] Preferably, the conveying pipeline is a quick-connect PE hose, and the inner wall of the quick-connect PE hose is provided with spiral ribs extending circumferentially along the pipe wall. When the slurry flows inside the quick-connect PE hose, the fluid generates radial secondary flow on the pipe cross-section due to the guiding effect of the spiral ribs. This keeps both the heavier sludge particles and the lighter straw fragments suspended and moving forward in the central area of ​​the pipe, effectively preventing solid materials from depositing at the bottom of the pipe and forming blockages, thus extending the distance of a single continuous conveying operation.

[0015] Preferably, a grid is provided on the inner side of the shovel bottom plate, and the gap between adjacent grid bars is greater than the width of the perforated groove. The grid forms the first line of defense, blocking large stones, thick tree trunks, and other hard debris outside the cutter box, protecting the cutter roller from impact damage.

[0016] Preferably, the surface of the tearing teeth is machined with spiral grooves. The spiral grooves are configured such that when the tearing teeth rotate with the tearing tooth roller to the biting area, the material has a relative sliding tendency on the surface of the tearing teeth. The inner wall of the spiral groove applies an axial thrust component pointing towards the root of the tearing teeth (i.e., the direction of the roller body) to the material, pushing the material towards the root of the teeth, increasing the contact area between the material and the tearing teeth and the friction holding time. This design significantly enhances the gripping force of the tearing teeth on easily slippery materials such as smooth mulch films, avoiding incomplete breaking due to material slippage.

[0017] Preferably, at least one water spray nozzle is provided below the comb-shaped grating, with the spray direction facing the hollow groove. The water spray nozzle is connected to a high-pressure water pump, and a water supply solenoid valve is provided on the connecting pipeline between the water spray nozzle and the high-pressure water pump. The water supply solenoid valve is electrically connected to a controller, and a pump suction negative pressure sensor electrically connected to the controller is provided inside the collection hopper. The controller controls the opening and closing of the water supply solenoid valve based on the negative pressure value detected by the pump suction negative pressure sensor. During long-term continuous operation, when the controller detects an abnormal increase in negative pressure through the pump suction negative pressure sensor, it automatically opens the water supply solenoid valve to perform pulsed reverse flushing, using high-pressure water flow to wash away the sticky sludge accumulated on the edge of the hollow groove, restoring the flow area of ​​the comb-shaped grating and ensuring the continuous stability of screening efficiency.

[0018] Compared to existing technologies, this invention constructs a forced-circulation crushing and screening mechanism, fundamentally preventing the entanglement of straw, mulch film, fishing nets, and other debris on the shearing rollers, tearing rollers, and pump body, thereby eliminating downtime for cleaning caused by entanglement. Specifically: The shearing blades with cutting edges are responsible for actively cutting straw and plastic film, while the tearing teeth use friction to fix fishing nets and roots. For fibrous materials such as straw and dead branches, the shearing blades use their cutting edges to cut them; for thin film materials such as plastic film, the shearing blades use their sharp tips to pierce and tear them; for linear materials such as fishing nets, the tearing teeth press and fix them before the shearing blades tear them, forming a coordinated "cutting and tearing" crushing process. This allows debris of different properties and shapes to be effectively crushed, rather than being entangled as in traditional augers.

[0019] The comb-shaped grating, serving as the bottom wall of the cutter box, has multiple perforated slots, maintaining a tiny gap of 2mm to 5mm between it and the lowest rotation trajectory of the cutter rollers. This gap serves a dual function: firstly, only materials crushed to a size smaller than the width of the perforated slots can pass through the comb-shaped grating and enter the collection hopper; insufficiently crushed materials larger than the perforated slots are intercepted on the upper surface of the comb-shaped grating. Secondly, as the rotating shearing blades and tearing teeth sweep across the upper surface of the comb-shaped grating, they utilize this tiny gap to scrape up the intercepted material and throw it back into the interlocking area between the two rollers for secondary crushing, forming a forced cycle. Thus, the material is repeatedly processed in a closed loop of "crushing → screening → return → re-crushing" until the particle size meets the requirements. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the main structure of the present invention; Figure 2 This is a schematic diagram of the main cross-sectional view of the toolbox structure of the present invention; Figure 3 For the present invention Figure 2 Enlarged schematic diagram of the structure at point A in the middle; Figure 4 This is a schematic cross-sectional view of the quick-connect PE hose of the present invention; Figure 5 This is a schematic diagram of the main sectional view of the shovel base plate of the present invention; Figure 6 For the present invention Figure 5 Schematic diagram of the cross-sectional structure along line A.

[0021] In the diagram: 1. Shovel and suction crushing unit; 11. Shovel bottom plate; 12. Grating; 13. Knife box; 131. First cycloidal hydraulic motor; 132. Second cycloidal hydraulic motor; 14. Shearing roller; 141. Shearing blade; 15. Tearing toothed roller; 151. Tearing tooth; 1511. Spiral groove; 16. Comb-type grating plate; 161. Hollow groove; 17. Collection hopper; 18. Forced feeding wheel; 2. Intermediate conveying unit; 21. Non-clogging centrifugal pump; 22. Quick-connect PE hose; 221. Spiral rib; 3. Water spray nozzle; 4. Small hydraulic motor; 5. Pump suction negative pressure sensor; 6. Clean water tank; 7. Water supply solenoid valve; 8. High-pressure water pump. Detailed Implementation

[0022] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the technical solution of this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0023] like Figures 1 to 2 as well as Figures 4 to 6 As shown, a special dredging device for rural water conservancy river engineering includes a shovel-suction crushing unit 1 and an intermediate conveying unit 2.

[0024] I. Shovel-Suction Crushing Unit The shovel-suction crushing unit 1 includes a shovel bottom plate 11, a grid 12, a cutter box 13, a shearing cutter roller 14, a tearing toothed roller 15, a comb-type grid plate 16, a collection hopper 17, and a forced feeding wheel 18.

[0025] The bottom plate 11 is made of 20mm thick NM400 wear-resistant steel plate, with the front end machined into a 30° acute-angle cutting edge for easy cutting into the riverbed silt layer. The bottom plate 11 is 1200mm wide, and side baffles with a height of 400mm are welded on both sides to prevent material from escaping laterally.

[0026] The grating 12 is located inside the bottom plate 11 and is made of multiple round steel bars with a diameter of 25mm arranged in parallel with an 80mm gap, welded together to form a planar grating structure. The grating 12 is used to block large hard debris with a diameter or length greater than 80mm, while allowing smaller materials such as silt, straw, and plastic film to pass through, thus playing a primary screening and protection role.

[0027] The cutter box 13 is a box-shaped structure welded from rectangular steel plates, with its upper opening located below the rear end of the shovel bottom plate 11. The bottom wall of the cutter box 13 is a comb-type grating plate 16. Inside the cutter box 13 are two horizontally parallel cutter shafts, a driving cutter shaft and a driven cutter shaft. A shearing roller 14 is fixedly mounted on the driving cutter shaft, and a tearing toothed roller 15 is fixedly mounted on the driven cutter shaft. The center distance between the two shafts is 220 mm.

[0028] The spatial relationship between the shovel bottom plate 11, the cutter box 13, and the comb-type grid plate 16 constitutes an inseparable integrated continuous operation chain of "shoveling-crushing-screening": after the shovel bottom plate 11 slides against the riverbed to shovel silt, the material directly enters the cutter box 13; while the comb-type grid plate 16 serves as the bottom wall of the cutter box 13, spatially forcing the material to pass through the comb-type grid plate 16 for screening before leaving the cutter box 13.

[0029] The shearing roller 14 is formed by welding 32 crescent-shaped shearing blades 141 arranged in a spiral along the axial direction of the drive shaft. The shearing blades 141 are made of high-chromium alloy steel (HRC58-60) and are wire-cut, with a crescent-shaped profile, a sharp front end, and a 45° sharp cutting edge on the inner arc edge. The maximum rotation diameter is 260mm. The spiral pitch is 120mm, and the axial angle between adjacent shearing blades 141 is 30°, ensuring that shearing blades 141 are always in a cutting state during the rotation of the shearing roller 14, resulting in uniform force distribution.

[0030] The tearing toothed roller 15 is welded together by four rows of blunt-tipped tearing teeth 151 arranged in a straight, staggered pattern along the driven cutter shaft. Each row has eight tearing teeth 151, which are cast from high-manganese steel (ZGMn13) and are straight cylinders with a diameter of 25 mm and a length of 80 mm, with hemispherical blunt tips at the front ends. The tearing teeth 151 in each row are evenly distributed at 90° around the driven cutter shaft, and adjacent rows are staggered by 40 mm in the axial direction, so that the tearing teeth 151 form a uniform, staggered coverage on the unfolded plane. The maximum rotation diameter of the tearing toothed roller 15 is the same as that of the shearing cutter roller 14, which is 260 mm.

[0031] The differentiated design of the shearing blade roller 14 and the tearing toothed roller 15 in terms of blade shape, rotation speed, and arrangement is specifically designed to complement the screening and circulation function of the comb-type grating 16. Specifically: the crescent-shaped design of the shearing blade 141 with its cutting edge is responsible for actively cutting straw and mulch film; the blunt-tipped straight cylindrical design of the tearing tooth 151 is responsible for using friction to fix fishing nets and roots. The difference in the shape of the two types of teeth is precisely to create a coordinated "cutting-tearing" scraping and retracing effect on the surface of the comb-type grating 16—the cutting edge of the shearing blade 141 effectively cuts long fibers overlapping the comb-type grating 16, while the hemispherical blunt tip of the tearing tooth 151 presses and retraces the material clumps to the biting area. Together, they ensure that the screening holes of the comb-type grating 16 are not blocked and that forced circulation continues.

[0032] The active cutter shaft is driven by the first cycloidal hydraulic motor 131, and the driven cutter shaft is independently driven by the second cycloidal hydraulic motor 132. Under standard operating conditions, the first cycloidal hydraulic motor 131 drives the shearing roller 14 to rotate at 120 r / min, and the second cycloidal hydraulic motor 132 drives the tearing toothed roller 15 to rotate at 40 r / min. The speed ratio of the two rollers is 3:1.

[0033] Experiments have shown that when the speed ratio is less than 2:1 (e.g., 1.5:1), the linear velocity difference between the shearing roller 14 and the tearing tooth roller 15 is too small. The tearing teeth 151 do not have sufficient residence time for the material in the biting zone, making it difficult to achieve an effective "fixing-tearing" synergy for highly resilient materials such as fishing nets and roots. The crushed material still contains many long fiber strips, which easily accumulate and bridge on the surface of the comb-type grid plate 16, leading to a decrease in screening efficiency. When the speed ratio is greater than 5:1 (e.g., 6:1), the speed of the tearing tooth roller 15 is too low. Although the residence time of a single tearing tooth 151 increases, the number of tearing teeth 151 participating in tearing per unit time decreases, reducing the material's throughput efficiency in the biting zone and decreasing processing capacity. Simultaneously, the excessive speed difference causes excessively violent relative movement between the shearing blade 141 and the tearing teeth 151, exacerbating surface wear on the tearing teeth 151. Furthermore, the shearing blade 141 tends to directly "scrape" away the material rather than effectively tear it, resulting in a worse crushing effect.

[0034] When the speed ratio is between 2:1 and 5:1, the linear velocity difference between the shearing roller 14 and the tearing tooth roller 15 is moderate. This ensures that the tearing teeth 151 have sufficient pressing and dwell time on materials such as fishing nets to form effective tearing, while also ensuring that a sufficient number of tearing teeth 151 participate in the work per unit time to maintain crushing efficiency. In particular, when the speed ratio is 3:1, it has the best comprehensive crushing effect for the mixture of straw, mulch film, and fishing nets commonly found in rural waterways.

[0035] The shearing roller 14 and the tearing toothed roller 15 rotate in opposite directions within the blade box 13. When viewed from above, the shearing roller 14 rotates clockwise and the tearing toothed roller 15 rotates counterclockwise, drawing the material into the biting area below and between the shearing roller 14 and the tearing toothed roller 15.

[0036] The comb-type grating 16, which is the bottom wall of the cutter box 13, is made of 16mm thick wear-resistant composite steel plate. Multiple long, narrow perforated slots 161 are cut into it using plasma cutting. The perforated slots 161 run parallel to the cutter shaft axis, with a width of 50mm and a length of 300mm. The width of the solid comb teeth between adjacent slots 161 is 25mm. The gap between the upper surface of the comb-type grating 16 and the minimum rotation trajectory of the shearing blades 141 and tearing teeth 151 is strictly controlled at 3mm. This gap ensures that the shearing blades 141 and tearing teeth 151 do not rigidly collide with the comb-type grating 16, while also allowing the ends of the shearing blades 141 and tearing teeth 151 to scrape up and throw backward any insufficiently crushed material stuck in the perforated slots 161 or accumulated on the upper surface of the comb-type grating 16, achieving forced secondary crushing.

[0037] It is particularly important to emphasize that if the gap between the upper surface of the comb-type grid plate 16 and the lowest rotation trajectory of the shearing blades 141 and tearing teeth 151 is greater than 5mm, multiple straws or clumps of fibrous debris will accumulate and become stuck in the gaps between the shearing blades 141 or tearing teeth 151 and the comb-type grid plate 16. Not only will these debris not be effectively scraped off and recycled for secondary crushing, but a dense fiber pad will also form at the bottom of the shearing rollers 14 and tearing rollers 15. This layer will gradually compact and completely block the slots 161 of the comb-type grid plate 16, resulting in the loss of screening function and effectively degrading it to a non-screening structure. In this state, the material scooped in by the bottom plate 11 cannot pass through the comb-type grid plate 16, the entire continuous "scooping-crushing-screening" chain breaks, and the device cannot operate.

[0038] If the gap is less than 2mm, in the complex bottom mud environment of rural river channels, the bottom mud contains hard particles such as sand, gravel, small stones and metal fragments. When these particles enter the cutter box 13 with the silt and get stuck between the shearing blade 141 and the comb-type grid plate 16, the gap is too small and the cutting edge of the shearing blade 141 will directly scrape against the comb-type grid plate 16. At best, this will aggravate the wear of the cutting edge of the shearing blade 141, and at worst, it will cause the cutting edge of the shearing blade 141 to break or the comb-type grid plate 16 to deform, making the device unable to operate continuously under harsh working conditions.

[0039] The preferred 3mm gap in this embodiment is a critical value determined after repeated testing of the mixture of typical debris (wet straw, plastic film fragments, and tangled fishing net threads) and bottom mud in rural waterways. At this gap, the end of the shearing blade 141 can apply effective shearing and scraping force (rather than crushing) to the material intercepted on the surface of the comb-type grating 1, achieving forced recirculation and self-cleaning of the comb-type grating 1; at the same time, it provides sufficient clearance for hard particles such as sand and gravel, allowing them to be squeezed into the perforated groove 161 or carried away with the mud, avoiding rigid jamming, thus simultaneously ensuring both the forced crushing and screening and the operational reliability of the equipment.

[0040] The collecting hopper 17 is welded below the cutter box 13 and located below the comb-type grid plate 16, with a structure that is wider at the top and narrower at the bottom. Its upper opening measures 800mm × 600mm; the lower opening is a circular flange with a diameter of 200mm. The collecting hopper 17 is used to receive the crushed material falling from the perforated trough 161 and guide it downwards to the non-clogging centrifugal pump 21. The inner wall of the collecting hopper 17 is coated with a 0.5mm polytetrafluoroethylene anti-stick coating to reduce wet mud adhesion.

[0041] The forced feeding wheel 18 is installed at the bottom outlet throat of the collection hopper 17. It consists of a main shaft of diameter and a cross-shaped rubber baffle, and is driven by a small hydraulic motor 4 at a speed of 5 r / min. When the material in the collection hopper 17 becomes loose and bridging, the forced feeding wheel 18 slowly rotates to break the static friction structure of the material, forcibly pushing the material into the non-clogging centrifugal pump 21 to ensure continuous feeding.

[0042] II. Intermediate Conveying Unit The intermediate delivery unit 2 includes a non-clogging centrifugal pump 21 and a quick-connect PE hose 22.

[0043] The inlet flange of the non-clogging centrifugal pump 21 is rigidly connected to the circular flange interface at the bottom of the collection hopper 17 via eight M16 bolts. The centrifugal pump flow channel width reaches 85mm. Since the width of the perforated grooves 161 of the comb-type grating 16 is 50mm, the maximum particle size of the material screened by the perforated grooves 161 does not exceed 50mm. The centrifugal pump flow channel width of 85mm is greater than this size, ensuring that all material passing through the comb-type grating 16 can pass unimpeded through the non-clogging centrifugal pump 21. The non-clogging centrifugal pump 21 is driven by a 30kW three-phase asynchronous motor with a rated speed of 1450r / min, a design head of 20m, and a rated flow rate of 80m³ / min. 3 / h, outlet flange diameter 150mm. Due to the forced circulation crushing mechanism of the comb-type grating plate 16 and the cutter roller with a gap of 2mm to 5mm, it has been ensured that the particle size of the material entering the collection hopper 17 is less than 50mm, while the centrifugal pump flow channel width of 85mm is greater than this value. The design eliminates the occurrence of blockage in the non-clogging centrifugal pump 21, and realizes closed-loop control of particle size from crushing to conveying.

[0044] The quick-connect PE hose 22 is made of high-density polyethylene, with an inner diameter of 150mm, a wall thickness of 6mm, and a standard length of 10m per section. Both ends of the quick-connect PE hose 22 are pre-installed with lever-type quick-connect clamps for rapid connection. The inner wall of the quick-connect PE hose 22 has four evenly distributed spiral ribs 221 along its circumference. The spiral ribs 221 have a semi-circular cross-section, a protrusion height of 6mm (approximately 4% of the inner diameter), and a spiral pitch of 250mm. When the mud flows, the spiral ribs 221 induce radial secondary flow, causing mud, sand, and straw fragments to suspend at the center of the quick-connect PE hose 22 and advance, effectively preventing deposition and clogging.

[0045] III. Monitoring and Control System The monitoring and control system is used to monitor the operational status in real time and automatically control the relevant actuators. The monitoring and control system includes a controller, a pump suction negative pressure sensor 5, a hydraulic oil circuit pressure sensor, and corresponding actuators.

[0046] The pump suction negative pressure sensor 5 is installed on the lower side wall of the collection hopper 17, near the suction inlet of the non-clogging centrifugal pump 21. Specifically, a threaded mounting hole is made in the side wall of the collection hopper 17, through which the pump suction negative pressure sensor 5 communicates with the inner cavity of the collection hopper 17. Its sensing end extends into the inside of the collection hopper 17 or is flush with the inner wall, and is used to detect the negative pressure value in the collection hopper 17 in real time. When the comb-type grid plate 16 becomes clogged, the suction resistance of the non-clogging centrifugal pump 21 increases, and the negative pressure in the collection hopper 17 rises accordingly.

[0047] A hydraulic oil pressure sensor is installed in the oil inlet pipe of the first cycloidal hydraulic motor 131 to detect the working oil pressure of the first cycloidal hydraulic motor 131 in real time. The working oil pressure is positively correlated with the load torque on the shearing roller 14, and can reflect the difficulty of crushing the material in the cutter box 13.

[0048] The controller uses an industrial-grade PLC (Programmable Logic Controller) or an embedded microcontroller. The signal input terminals of the controller are electrically connected to the pump suction negative pressure sensor 5 and the hydraulic oil circuit pressure sensor, respectively, and the signal output terminals are electrically connected to the water supply solenoid valve 7 of the water nozzle 3 and the hydraulic proportional speed control valve of the first cycloidal hydraulic motor 131 of the shearing roller 14, respectively.

[0049] like Figure 2 As shown, at least one water spray nozzle 3 is installed below the comb-type bar screen 16 and in the space above the collection hopper 17. The water spray nozzle 3 is connected to the outlet of a high-pressure water pump 8 via a pipeline, and the inlet of the high-pressure water pump 8 is connected to the clean water tank 6. The high-pressure water pump 8 is driven by an independent motor and remains in a continuous running state during dredging operations. A water supply solenoid valve 7 is connected in series on the pipeline between the water spray nozzle 3 and the high-pressure water pump 8, and the water supply solenoid valve 7 is electrically connected to the signal output terminal of the controller. When the controller issues a flushing command, the water supply solenoid valve 7 opens, and high-pressure water flows through the water spray nozzle 3 and sprays onto the comb-type bar screen 16; when the flushing is finished, the water supply solenoid valve 7 closes, and the water spraying stops.

[0050] The controller has a preset normal operating range for the negative pressure of the centrifugal pump 21 without blockage. When the negative pressure value detected by the pump suction negative pressure sensor 5 exceeds 20% to 30% of the upper limit of the normal operating range, the controller determines that the comb-type bar screen 16 is slightly blocked and automatically opens the water supply solenoid valve 7 to perform pulse-type reverse flushing; when the negative pressure value exceeds 50% of the upper limit of the normal operating range, the controller determines that the blockage is serious and, in addition to continuous flushing, can also issue an alarm signal; when the negative pressure value drops back to within 110% of the upper limit of the normal operating range, the controller closes the water supply solenoid valve 7 to stop flushing.

[0051] When the hydraulic pressure sensor detects that the oil pressure exceeds 1.5 times the peak value of the oil pressure fluctuation under normal cutting conditions of the shearing roller 14, the controller determines that a high-toughness material has been encountered in the cutter box 13. It automatically outputs a control signal to the hydraulic proportional speed control valve of the first cycloidal hydraulic motor 131 to instantly increase the hydraulic flow rate and increase the rotational speed of the shearing roller 14, thereby increasing the speed difference between the shearing roller 14 and the tearing toothed roller 15 to overcome the material resistance. When the oil pressure drops to less than 1.2 times the normal peak value, the controller restores the standard rotational speed of the shearing roller 14.

[0052] In addition, the controller can also start the water supply solenoid valve 7 for preventive flushing according to a preset time cycle, without waiting for the negative pressure to rise.

[0053] IV. Structural Optimization As a preferred option, such as Figure 3 As shown, the surface of the tearing tooth 151 is machined with a spiral groove 1511. The spiral direction of the spiral groove 1511 is designed as follows: when the tearing tooth 151 rotates with the tearing tooth roller 15 into the biting area, the pressed wet and slippery mulch and other materials tend to slide towards the tooth tip relative to the surface of the tearing tooth 151. At this time, the inner wall of the spiral groove 1511 applies an axial thrust component pointing towards the tooth root to the material, pushing the material towards the root of the tearing tooth 151, increasing the contact area and friction time, preventing slippage, and improving the gripping reliability.

[0054] V. Work Process During dredging operations, this device is towed to the riverbank, and the hydraulic boom lowers the shovel-sucking crushing unit 1 to the bottom of the riverbed. The shovel base plate 11 slides along the riverbed, and the shoveled surface silt, along with straw, plastic film, fishing nets, and other debris, is transported backward by the subsequent material. Large, hard debris is blocked by the grid 12, and the remaining material passes through the grid 12 and enters the cutter box 13.

[0055] Material entering the cutter box 13 falls into the engagement zone between the shearing roller 14 and the tearing tooth roller 15. For fibrous materials such as straw and dead branches, the shearing blade 141 uses its sharp edge to cut them; for thin film materials such as mulch film, the shearing blade 141 uses its sharp tip to pierce and tear them; for linear materials such as fishing nets, the tearing teeth 151 use the friction of their blunt surfaces to press and fix them, and they are effectively torn apart by the tearing force generated by the differential rotation of the shearing roller 14 and the tearing tooth roller 15. Material crushed to a size less than 50mm falls into the collection hopper 17 through the hollow groove 161 of the comb-type grid plate 16. Incompletely crushed material larger than 50mm is intercepted by the comb-type grid plate 16 and scraped off from the upper surface of the comb-type grid plate 16 by the rotating shearing blade 141 and tearing teeth 151 and thrown back into the engagement zone for secondary crushing. This cycle continues until the particle size meets the standard.

[0056] Material falling into the collection hopper 17 is pushed by the forced feeding wheel 18 into the suction port of the non-clogging centrifugal pump 21. After being pressurized by the non-clogging centrifugal pump 21, it is transported to the onshore secondary treatment equipment or directly discharged through the quick-connect PE hose 22. During the transportation process, the spiral ribs 221 on the inner wall of the quick-connect PE hose 22 induce micro-vortex flow to prevent material deposition.

[0057] During dredging operations, this device employs a sliding shovel plate 11 along the riverbed to remove sediment, horizontally moving only the top 10-15cm of sediment, minimizing disturbance to the original riverbed soil. The negative pressure of the clog-free centrifugal pump 21 is confined to the inside of the collection hopper 17, and the suction inlet is not directly exposed to open water. Therefore, unlike traditional squeegee heads, it avoids the large-scale suspension and diffusion of sediment caused by violent agitation, effectively reducing secondary pollution to downstream water bodies during dredging and protecting the habitat of benthic organisms.

[0058] During long-term continuous operation, the controller receives signals from the pump suction negative pressure sensor 5 and the hydraulic oil circuit pressure sensor in real time. When an abnormal increase in the pump suction negative pressure of the non-clogging centrifugal pump 21 is detected, the water supply solenoid valve 7 is automatically opened, and the water spray nozzle 3 is started to perform pulse-type reverse flushing on the comb-type grid plate 16; when an abnormal increase in hydraulic oil pressure is detected, the proportional speed control valve is automatically adjusted to increase the speed of the shearing roller 14.

[0059] In summary, the technical solution formed by the bottom plate 11, shearing roller 14, tearing toothed roller 15, and comb-type grid plate 16 which also functions as a bottom wall in this embodiment, with a specific gap of 2mm to 5mm, synergistically solves the chain problem of "inability to cut, inability to screen, and easy pump blockage" in traditional equipment when processing fibrous impurities.

[0060] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A special dredging device for rural water conservancy and river engineering, characterized in that, include: The front-end shovel and crushing unit includes: a shovel bottom plate, used to slide along the riverbed and shovel off the surface silt; A blade box, located behind the shovel base plate, has a bottom wall made of a comb-shaped grating plate with multiple elongated slots. A shearing roller and a tearing roller are rotatably connected inside the blade box. The shearing roller and the tearing roller are arranged horizontally parallel to each other and rotate in opposite directions. The shearing roller is equipped with crescent-shaped shearing blades with cutting edges, and the tearing roller is equipped with blunt-tipped tearing teeth. The gap between the lowest rotational trajectory of the shearing blades and tearing teeth and the upper surface of the comb-shaped grating plate is 2mm to 5mm. A collection hopper, connected to the lower side of the comb-shaped grating plate, is used to collect materials falling from the slots. The intermediate conveying unit includes a non-clogging centrifugal pump and a conveying pipeline. The suction port of the non-clogging centrifugal pump is connected to the bottom outlet of the collection hopper, and the inlet end of the conveying pipeline is connected to the discharge port of the non-clogging centrifugal pump.

2. The special dredging device for rural water conservancy river engineering according to claim 1, characterized in that: The shearing roller and the tearing toothed roller are respectively connected to a cycloidal hydraulic motor, and the speed ratio of the shearing roller to the tearing toothed roller is 2:1 to 5:

1.

3. The special dredging device for rural water conservancy river engineering according to claim 2, characterized in that: A hydraulic proportional speed control valve is connected to the inlet or return oil line of the cycloidal hydraulic motor connected to the shearing roller. The hydraulic proportional speed control valve is used to adjust the rotational speed of the shearing roller.

4. The special dredging device for rural water conservancy river engineering according to claim 1, characterized in that: The shearing blades are arranged in a spiral along the axial direction of the shearing roller, and the tearing teeth are arranged in a straight, staggered manner along the axial direction of the tearing tooth roller.

5. The special dredging device for rural water conservancy river engineering according to claim 1, characterized in that: A forced feeding dial is rotatably connected to the bottom outlet of the collection hopper, and the forced feeding dial is connected to a drive device.

6. The special dredging device for rural water conservancy river engineering according to claim 1, characterized in that: The width of the flow channel of the non-clogging centrifugal pump is greater than or equal to the width of the hollowed-out groove.

7. The special dredging device for rural water conservancy river engineering according to claim 1, characterized in that: The conveying pipeline is a quick-connect PE hose, and the inner wall of the quick-connect PE hose is provided with spiral ribs extending circumferentially along the pipe wall.

8. The special dredging device for rural water conservancy river engineering according to claim 1, characterized in that: The inner side of the shovel bottom plate is provided with a grid, and the gap between adjacent grid bars is greater than the width of the hollow groove.

9. The special dredging device for rural water conservancy river engineering according to claim 1, characterized in that: The surface of the tearing tooth is machined with a spiral groove, and the spiral direction of the spiral groove is configured such that when the tearing tooth rotates with the tearing tooth roller to the biting area, the material slides relative to the surface of the tearing tooth, and the spiral groove generates an axial thrust pointing towards the root of the tearing tooth.

10. The special dredging device for rural water conservancy river engineering according to claim 1, characterized in that: At least one water nozzle is provided below the comb-type grating, the spray direction of the water nozzle is towards the hollow groove, the water nozzle is connected to a high-pressure water pump, a water supply solenoid valve is provided on the connecting pipe between the water nozzle and the high-pressure water pump, the water supply solenoid valve is electrically connected to a controller, and a pump suction negative pressure sensor electrically connected to the controller is provided inside the collection hopper.

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