Suction jet pump, suction method thereof and ditcher

Abstract

The invention relates to the technical field of subsea pipeline laying, in particular to a suction jet pump, a suction method of the suction jet pump and a ditcher. The suction jet pump comprises an annular jet pump body, the annular jet pump body comprises a suction pipe and a single discharge pipe, two sets of rotatable suction arms which are symmetrically arranged are arranged at the inlet end of the suction pipe, and synchronous suction on the two sides of the interior of the groove is achieved through the two sets of rotatable suction arms. And the adjustment of the suction position and the crushing and conveying of the seabed slurry are realized through the rotatable suction arm, and the sucked seabed slurry is uniformly discharged through the single discharge pipe. The rotatable suction arm comprises a rotation driving mechanism, a suction pipe, a crushing and conveying driving mechanism and a crushing and conveying mechanism. The crushing and conveying mechanism comprises an outer-layer screw and an inner-layer screw arranged in the outer-layer screw, the crushing and conveying driving mechanism drives the inner-layer screw in the outer-layer screw to rotate synchronously, seabed slurry particle crushing, rotational flow acceleration and negative pressure enhancement are achieved, the device can be suitable for different seabed environments, and the suction efficiency is high.

Description

Technical Field

[0001] The present invention relates to the technical field of submarine pipeline laying, and in particular to a suction jet pump, a suction method thereof, and a trenching machine. Background Art

[0002] Marine pipelines include submarine oil and gas gathering and transportation pipelines, trunk pipelines, attached booster platforms, and main pipes connecting the pipelines to the platforms. The transportation process is the same as that of onshore pipelines, but because marine pipeline projects are carried out in the sea, the construction methods differ from those of onshore pipeline projects. Existing methods for laying submarine pipelines include direct laying and pipe landfill. Direct laying is a simple method that lays the pipeline directly on the seabed without the need for additional trenches. This method is suitable for stable underwater environments, such as those with a flat and unobstructed seabed. Pipe landfill involves burying the pipeline in an underwater trench. This method requires ensuring sufficient burial depth, typically 3 to 4 times the pipe diameter, to prevent problems such as ship anchoring and riverbed scouring.

[0003] Because the pipeline landfill method requires a trench, trenching machines are used during the pipeline laying process. Existing trenching machines include jet trenchers, chain trenchers, plow trenchers, and underwater diamond saw trenchers. Jet trenchers are suitable for sandy or soft clay seabeds, using high-pressure water jets to scour the seabed to form a trench, which then naturally silts and covers the pipeline. While highly efficient, they are ineffective on hard soils. Chain trenchers and plow trenchers are suitable for hard clay and gravel seabeds, creating trenches by directly cutting the soil. Underwater diamond saw trenchers are suitable for rocky seabeds.

[0004] The seabed environment is complex. In actual trenching operations, existing trenching machines are equipped with corresponding suction equipment to suck out the sediment, clay, or gravel particles that return during the trenching process to ensure the trench is flat and deep enough, ensuring smooth laying of the pipeline. However, the current suction equipment has been found to have the following shortcomings in actual operation:

[0005] 1. It has a good suction effect on small particles of mud, but it has a poor suction effect on large particles of impurities, which can easily cause equipment blockage or damage, which not only increases the maintenance cost of the equipment, but also reduces the operating efficiency.

[0006] 2. Existing suction equipment relies solely on a single suction port during operation. A single trencher requires at least two sets of suction equipment, consuming significant energy. Furthermore, after suctioning from a single port, the sucked mud must be discharged separately from both sides of the trencher, requiring at least two mud outlets, significantly disturbing the seabed environment. Furthermore, the two suction heads located on either side of the trench cannot achieve multi-directional suction, compromising both suction efficiency and smoothness when the trench is wide.

[0007] 3. The existing suction equipment has a fixed structure and parameters, making it difficult to flexibly adjust according to different seabed soil types and operating depths, resulting in poor adaptability of the equipment in different environments. In addition, when sediment siltation occurs during the suction process, it relies solely on a single suction port for suction, resulting in low processing efficiency.

[0008] Therefore, it is now urgent to improve the suction equipment on the existing trencher.

[0009] The above information disclosed in this background technology is only used to increase the understanding of the background technology of this application, and should not be regarded as an admission or any form of implication that the information constitutes the prior art already known to ordinary technicians in this field. Summary of the Invention

[0010] In order to address the shortcomings of the existing technology, the present invention improves the suction efficiency and reduces the disturbance to the seabed environment through the structural arrangement of two sets of rotatable suction arms, a drag reduction mechanism, a movable nozzle and a movable throat. At the same time, it can flexibly adjust the suction jet pump and its suction method and trenching machine according to different seabed conditions.

[0011] The technical solution of the present invention is:

[0012] A suction jet pump includes an annular jet pump body that provides power for suction. The annular jet pump body includes a suction pipe and a single discharge pipe. Two groups of symmetrically arranged rotatable suction arms are provided at the inlet end of the suction pipe. Synchronous suction on both sides of the groove is achieved through the two groups of rotatable suction arms, and the suction position is adjusted and the seabed slurry is crushed and transported through the rotatable suction arms. The sucked seabed slurry is discharged uniformly through the single discharge pipe.

[0013] The rotatable suction arm includes a rotation drive mechanism, a suction pipe, a crushing and conveying drive mechanism, and a crushing and conveying mechanism. The suction pipe is connected to the intake pipe via the rotation drive mechanism, and the rotation drive mechanism drives the suction pipe to swing forward and backward or left and right. The crushing and conveying mechanism is located at the suction inlet of the suction pipe and includes an outer spiral and an inner spiral disposed within the outer spiral. The crushing and conveying drive mechanism drives the inner spiral within the outer spiral to rotate synchronously, achieving seabed slurry particle crushing, vortex acceleration, and negative pressure enhancement.

[0014] Furthermore, the rotation drive mechanism includes front and rear drive motors, gear I, ring gear I, left and right drive motors, gear II, and ring gear II. The front and rear drive motors are mounted on the outer wall of the suction pipe and connected to ring gear I via gear I. Ring gear I is mounted at the inlet end of the suction pipe. Ring gear I is connected to ring gear II via a connecting elbow, which also connects the suction pipe to the suction pipe. Ring gear II is connected to left and right drive motors via gear II. The left and right drive motors are mounted on the sidewalls of the connecting elbow.

[0015] Furthermore, the suction port of the suction pipe is configured as a trumpet-shaped structure, and the crushing and conveying drive mechanism includes a crushing and conveying motor, a gear III and a gear ring III, the gear III is vertically arranged and connected to the output end of the crushing and conveying motor, the gear ring III is horizontally arranged on the inner wall of the suction port and meshes with the gear III, the outer spiral is fixed on the lower surface of the gear ring III, and the inner spiral is nested in the upper end of the inner side of the outer spiral.

[0016] Furthermore, the outer spiral is configured as a plurality of variable-section blades arranged circumferentially at intervals, the outer diameter of the outer spiral surrounded by the plurality of variable-section blades matches the outer diameter of the suction port, and the inner crushing spiral is configured as a plurality of circumferentially arranged serrated protrusions, the serrated protrusions including a fixed end and a shearing end, and the shearing end is arranged toward the center of the suction port.

[0017] Furthermore, the variable-section blade includes a suction surface, a leading edge cutting surface, a pressure surface, a transition surface, and a trailing edge vortex surface, which are arranged in sequence in a clockwise direction. The suction surface is configured as an inwardly concave arc surface, and the pressure surface is configured as an outwardly convex arc surface; the leading edge cutting surface is configured between the suction surface and the pressure surface and connects the suction surface and the pressure surface; the trailing edge vortex surface is configured on one side of the suction surface and is configured as a smooth surface with an arc. The transition surface between two adjacent variable-section blades is configured as a twisted parabolic structure, and the transition surface of each variable-section blade is configured between the pressure surface and the trailing edge vortex surface and connects the pressure surface and the trailing edge vortex surface.

[0018] The suction surface is a concave arc that traps the water flow during rotation, forming a low-pressure vortex. The pressure surface is convex and is responsible for the secondary crushing of sediment. The leading edge cutting surface is beveled like a knife, facing the sediment layer and breaking up large particles first. The trailing edge vortex surface is smooth and slightly curved, releasing continuous vortices to peel off attachments. The adjacent transition surfaces on both sides are twisted parabolas, which gradually narrow the flow channel between adjacent blades to prevent backflow. Circumferentially, several such blades are arranged at equal angles and staggered to form a continuous spiral staircase, which resembles the staggered blades of a fan and the spiral edge of a drill bit. They rotate synchronously, drawing in sediment from the outer edge, breaking it layer by layer, and pushing it upward along the tapered channel. Finally, it converges into a strong upflow in the center and is efficiently sucked in by the jet pump.

[0019] Furthermore, a drag reduction mechanism is provided on the suction pipe, and the drag reduction mechanism is close to the intersection of two groups of rotatable suction arms. The drag reduction mechanism is close to the intersection of two groups of rotatable suction arms. The drag reduction mechanism includes an air inlet, an air inlet ring and several streamlined air outlets arranged in a ring on the air inlet ring. The air inlet angle of the air outlet is 12° to 18°.

[0020] Furthermore, the annular jet pump body includes a suction chamber, which is connected to the output end of the suction pipe. The upper end of the suction chamber is provided with a working fluid inlet connected to the suction chamber. The suction chamber is provided with a movable nozzle, which can move horizontally back and forth within the suction chamber. The output end of the suction chamber is connected to a movable throat pipe, the length of which is adjustable. The output end of the movable throat pipe is connected to a diffuser, and the discharge pipe is connected to the output end of the diffuser.

[0021] Furthermore, the movable nozzle includes a nozzle moving motor, a tooth groove and an annular nozzle. The nozzle moving motor is fixed on both sides of the suction chamber, and the tooth groove is embedded on both sides of the annular nozzle and is symmetrically distributed on the left and right. The output end of the nozzle moving motor is engaged with the tooth groove, and the output end of the nozzle moving motor rotates, driving the tooth groove to move, and further driving the annular nozzle to move.

[0022] The movable throat includes a hydraulic rod, a first throat pipe and a second throat pipe. The first throat pipe is fixedly connected to the outlet of the suction chamber, and the second throat pipe is nested on the outside of the first throat pipe and fixedly connected to the diffuser. One end of the hydraulic rod is fixed at the outlet of the suction chamber, and the other end of the hydraulic rod is fixed on the second throat pipe. The extension and retraction of the hydraulic rod drives the second throat pipe away from or close to the outlet of the suction chamber.

[0023] A suction method includes the aforementioned suction jet pump, wherein a turbine flowmeter and a high-temperature pressure sensor are installed at the outlet of the movable nozzle to monitor the working fluid flow rate Qp and pressure Pp, with data accuracy reaching 0.1 level and a response time of less than 200ms. An ultrasonic flowmeter and a differential pressure transmitter are installed at the discharge pipe to measure the discharge flow velocity vd and the pressure difference ΔP = Pd-Ps, and simultaneously calculate the volume flow rate and pressure rise value.

[0024] The above-mentioned suction method comprises the following steps:

[0025] 1: According to the predetermined suction direction, adjust the angles of the two sets of suction arms to align them with the target suction area; the outer spiral rotates to generate axial thrust, pushing large particles of impurities toward the throat. At the same time, a turbulent zone is formed at the edge of the outer spiral, destroying the agglomeration structure of the mud particles and reducing the fluid viscosity; the inner crushing spiral performs secondary shear crushing on the sucked mud, impacting particles with a diameter of >50mm to <20mm to avoid clogging the annular nozzle and throat.

[0026] 2: During the suction process, the drag reduction mechanism is started synchronously, the air outlet is opened, and an appropriate amount of air is injected into the fluid to form a gas-liquid mixture; the electromagnetic flowmeter and piezoresistive pressure sensor installed at the rear end of the drag reduction mechanism near the suction chamber collect the flow rate Qs and static pressure Ps of the sucked fluid in real time, and transmit at least 10 sets of data per second to the intelligent monitoring and computing system.

[0027] 3. During the suction process, an intelligent monitoring and calculation system operates synchronously, monitoring the cross-sectional flow rate and pressure at the suction pipe, annular nozzle outlet, and discharge pipe in real time. Based on this data, the intelligent monitoring and calculation system automatically calculates performance parameters such as the ratio of the suction fluid mass flow rate to the working fluid mass flow rate (q = Qs / Qp), the ratio of the pressure rise to the working fluid pressure (p = ΔP / Pp), and the efficiency (η = q·p). This data is displayed synchronously on the user interface and stored in a local database, forming a historical trend curve. Based on this real-time performance data, the suction chamber variable nozzle system and throat length control system are automatically adjusted.

[0028] Furthermore, in the suction chamber variable nozzle system, the encoder achieves nozzle position accuracy control of ±0.5mm; when q<0.8 or η<60%, the nozzle moves toward the throat and reduces the suction angle (adjusted by 5° each time) until q returns to the range of 0.9-1.1; if q=0.6, it is adjusted quickly at the set maximum speed; if q=0.75, it is fine-tuned at the set low speed.

[0029] In the throat length control system, the hydraulic system response time is less than 1s. When p is less than 0.3 or the discharge pipe pressure fluctuation is greater than ±15%, the hydraulic cylinder extends the throat by 20-50mm each time until p stabilizes at 0.4-0.6; if Qs continues to be high, the throat length is prioritized to maintain the lower limit to avoid excessive extension that causes fluid retention.

[0030] A trenching machine comprises the above-mentioned suction jet pump.

[0031] The beneficial effects achieved by the present invention are:

[0032] 1. The suction jet pump of this invention, through its structural arrangement of two sets of rotatable suction arms, can adapt to different seabed conditions for suction. It is particularly effective for seabeds containing large impurities, achieving high overall suction efficiency. By coordinating with the drag reduction mechanism, it reduces energy consumption and suction blockage rates, thereby improving operational efficiency. Furthermore, it reduces the impact and wear of solid particles on the pipe wall, extending the equipment's service life and reducing maintenance costs. Furthermore, it further reduces noise and vibration during operation, minimizing disturbances to the seabed environment.

[0033] 2. The present invention requires only one suction jet pump to achieve perfect trenching, reducing energy consumption compared to using two suction devices. Furthermore, the design of two rotatable suction arms significantly improves adaptability to wider trenches, enhancing trenching efficiency. Furthermore, the single discharge pipe reduces disturbance to the marine environment compared to a system with two discharge pipes on either side.

[0034] 3. The crushing and conveying mechanism set in the suction jet pump of the present invention realizes the "coarse crushing-fine crushing" classification treatment through the structural design of the inner and outer spirals of the crushing and conveying mechanism, and further realizes the composite function integration of particle crushing, swirl acceleration and negative pressure enhancement, which significantly improves the adaptability and reliability of the equipment.

[0035] 4. The suction jet pump in the present invention can be flexibly adjusted according to different seabed soil types and operating depths through the structural design of the movable nozzle and movable throat, thereby improving the adaptability of the equipment in different seabed environments, realizing multi-purpose use of one machine, and greatly reducing construction costs.

[0036] 5. The jet pump in the present invention has two rotatable suction arms, which can simultaneously perform suction on both sides of the trench. It is more adaptable to the integrated digging-laying-burying submarine cable laying trenching equipment. It can perform mud suction on both sides of the pipe and cable while laying the pipe and cable, and has high suction efficiency, avoiding the backflow of sediment during the suction process and improving work efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a schematic diagram of the overall structure of the suction jet pump of the present invention.

[0038] Figure 2 yes Figure 1 Schematic diagram of the structure of the rotatable suction arm in group 1.

[0039] Figure 3 yes Figure 2 Schematic diagram of the structure of the middle elbow connection.

[0040] Figure 4 yes Figure 1 Schematic diagram of the structure of the connection between the crushing and conveying mechanism and the crushing and conveying drive mechanism.

[0041] Figure 5 yes Figure 1 Schematic diagram of the structure of the middle and outer spirals.

[0042] Figure 6 It is a schematic diagram of a pre-acceleration zone formed by the sediment to be sucked and the suction port of the suction pipe.

[0043] Figure 7 yes Figure 1 Schematic diagram of the structure of the drag reduction mechanism.

[0044] Figure 8 It is a cloud diagram of solid phase particle distribution with different air addition amounts.

[0045] Figure 9 yes Figure 1 perspective drawing.

[0046] Figure 10 yes Figure 1 Schematic diagram of the movable nozzle structure.

[0047] Figure 11 It is a neural network diagram of the control system in the present invention.

[0048] Figure 12 It is a flow chart of the suction method of the present invention.

[0049] In the figure, 1. annular jet pump body; 11. suction pipe; 12. discharge pipe; 13. working fluid inlet; 14. suction chamber; 2. rotatable suction arm; 21. crushing and conveying mechanism; 211. outer spiral; 2111. suction surface; 2112. leading edge cutting surface; 2113. pressure surface; 2114. transition surface; 2115. trailing edge vortex surface; 212. inner spiral; 22. crushing and conveying drive mechanism; 221. crushing and conveying motor; 222. gear III; 223. gear ring III; 23. suction pipe; 231. suction port; 24 , rotation drive mechanism; 241, front and rear drive motors; 242, gear I; 243, gear ring I; 244, left and right drive motors; 245, gear II; 246, gear ring II; 247, connecting flange; 248, sealing rubber ring; 25, connecting elbow; 3, drag reduction mechanism; 31, air inlet; 32, air inlet ring; 33, air outlet buckle; 4, movable nozzle; 41, nozzle moving motor; 42, tooth groove; 43, annular nozzle; 5, movable throat; 51, first throat; 52, hydraulic rod; 53, second throat; 6, sensor. DETAILED DESCRIPTION

[0050] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.

[0051] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention as claimed, but merely represents preferred embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort shall fall within the scope of protection of the present invention.

[0052] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings.

[0053] In the description of the present invention, it should be noted that the terms "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, or are the orientation or position relationship in which the product of the invention is usually placed when in use. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", "third", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0054] In the description of the present invention, it should be noted that, unless otherwise specified or limited, the terms "disposed" and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0055] In the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Furthermore, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0056] The following describes embodiments of the present invention in detail. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended only to explain the present invention and are not to be construed as limiting the present invention.

[0057] Example 1

[0058] like Figures 1 to 10 As shown, the present invention provides a suction jet pump, including an annular jet pump body 1 that provides power for suction. The annular jet pump body 1 includes a suction pipe 11 and a single discharge pipe 12. The inlet end of the suction pipe 11 is provided with two sets of symmetrically arranged rotatable suction arms 2. The two sets of rotatable suction arms 2 are used to achieve synchronous suction on both sides of the groove, and the rotatable suction arms 2 are used to adjust the suction position and crush and transport the seabed slurry. The sucked seabed slurry is uniformly discharged through the single discharge pipe 12. The process of discharging through the single discharge pipe 12 reduces the area of ​​disturbance to the marine environment compared to the method of having two discharge pipes 12 on both sides.

[0059] In this embodiment, the rotatable suction arm 2 includes: a rotation drive mechanism 24, a suction pipe 23, a crushing and conveying drive mechanism 22, and a crushing and conveying mechanism 21. The suction pipe 23 is connected to the suction pipe 11 through the rotation drive mechanism 24, and the rotation drive mechanism 24 drives the suction pipe 23 to swing forward and backward or left and right. Specifically, the rotation drive mechanism 24 includes a front and rear drive motor 241, a gear I 242, a ring gear I 243, a left and right drive motor 244, a gear II 245, and a ring gear II 246. The front and rear drive motor 241 is arranged on the outer wall of the suction pipe 11, and is connected to the ring gear I 243 through the gear I 242. The ring gear I 243 is arranged at the inlet end of the suction pipe 11. Specifically, the gear I 242 drives the ring gear I 243 embedded in the outer wall of the connecting elbow to rotate, that is, drives the connecting elbow 25 to rotate around the axis to achieve the purpose of rotating forward and backward. Specifically, the output end of the front-to-rear drive motor 241 is connected to gear I 242, which is further meshed with ring gear I 243. The front-to-rear drive motor 241 rotates, driving gear I 242, which in turn drives ring gear I 243. During the rotation of ring gear I 243, the suction pipe 23 swings back and forth, achieving suction within the groove at a certain distance, thus expanding the suction range.

[0060] The ring gear I 243 is connected to the ring gear II 246 via the connecting elbow 25, and the connecting elbow 25 connects the suction pipe 11 and the suction pipe 23. The ring gear II 246 is connected to the left and right drive motor 244 via gear II 245. The left and right drive motor 244 is mounted on the side wall of the connecting elbow 25. Specifically, the left and right drive motor 244 drives gear II 245 to rotate, which drives the ring gear II 246 embedded in the outer wall of the suction arm to rotate, that is, drives it to rotate around the axis, achieving the purpose of left and right rotation. Specifically, the output end of the left and right drive motor 244 is connected to gear II 245, which is further meshed with the ring gear II 246. The rotation of the left and right drive motor 244 drives gear II 245 to rotate, which in turn drives the ring gear II 246 to rotate. During the rotation of the ring gear II 246, the suction pipe 23 is driven to swing left and right, achieving suction within the groove and expanding the suction range. In order to ensure the overall sealing, protrusions larger than the pipe diameter are provided at the connection positions at both ends of the connecting elbow 25, and the connection is made through a connecting flange 247. Each connection has a groove for placing a sealing rubber ring 248, and the sealing rubber ring 248 is placed in the groove to ensure sealing during rotation.

[0061] The two sets of rotatable suction arms 2 enable full excavation of the trench, front and back, left and right, and avoid the problem of sediment backflow on the soft seabed caused by the suction process of a single suction pipe 23. The two sets of rotatable suction arms 2 allow the pipeline to be laid between the two suction arms during cable laying, ensuring the smoothness of the excavated trench. After excavation, the pipeline can be laid directly in the excavated trench, improving pipeline laying efficiency.

[0062] In this embodiment, the crushing and conveying mechanism 21 is disposed at the suction inlet of the suction pipe 23 and includes an outer spiral 211 and an inner spiral 212 disposed within the outer spiral 211. The crushing and conveying drive mechanism 22 drives the inner spiral 212 within the outer spiral 211 to rotate synchronously. The spiral structure generates centripetal force and axial thrust during rotation, forming a strong negative pressure zone, effectively enhancing the suction force, making it easier for particles in the fluid to be rolled up and enter the suction pipe 23. This achieves the crushing of seabed slurry particles, swirl acceleration, and negative pressure enhancement.

[0063] Specifically, the suction port 231 of the suction pipe 23 is designed as a trumpet-shaped structure with an expansion angle β of 60°-90°. This guides the slurry into the spiral zone along a tangential direction, forming an initial vortex. This, combined with the rotational kinetic energy of the spiral blades, further enhances the negative pressure. Furthermore, the opening is enlarged to prevent clogging. Inner spirals 212 are distributed circumferentially along the inner wall of the outer spiral 211, guiding the slurry into an initial vortex, which, combined with the spiral kinetic energy, enhances the negative pressure.

[0064] The crushing and conveying drive mechanism 22 includes a crushing and conveying motor 221, gear III 222, and gear ring III 223. Gear III 222 is vertically arranged and connected to the output end of the crushing and conveying motor 221. Gear ring III 223 is horizontally arranged on the inner wall of the suction port 231 and meshes with gear III 222. The outer spiral 211 is fixed to the lower surface of gear ring III 223, and the inner spiral 212 is nested at the upper end of the inner side of the outer spiral 211. The gear set module m = 3-5 and the transmission ratio i = 1:1.5 of the crushing and conveying drive mechanism 22 enhance the fluid shear effect. This design realizes the integrated function of particle crushing, swirl acceleration, and negative pressure enhancement through the "coarse crushing-fine crushing" classification process of the inner spiral 212 and the outer spiral 211, significantly improving the adaptability and reliability of the equipment.

[0065] The outer spiral 211 is configured as a plurality of variable-section blades that are circumferentially arranged at intervals.

[0066] like Figure 5 As shown, the variable-section blade includes a suction surface 2111, a leading edge cutting surface 2112, a pressure surface 2113, a transition surface 2114, and a trailing edge vortex surface 2115, which are arranged in a clockwise direction. The suction surface 2111 is configured as a concave arc surface, and the pressure surface 2113 is configured as a convex arc surface. The leading edge cutting surface 2112 is disposed between the suction surface 2111 and the pressure surface 2113 and connects the suction surface 2111 and the pressure surface 2113. The trailing edge vortex surface 2115 is disposed on one side of the suction surface 2111 and is configured as a smooth curved surface. The transition surface 2114 is configured as a twisted parabola structure and is disposed between the pressure surface 2113 and the trailing edge vortex surface 2115 and connects the pressure surface 2113 and the trailing edge vortex surface 2115. The suction surface 2111 is a concave arc surface that traps water flow during rotation, forming a low-pressure vortex. The pressure surface 2113 is convex, and is responsible for the secondary crushing of the sediment. The leading edge cutting surface 2112 is beveled like a knife, facing the sediment layer, and breaking up large particles first. The trailing edge vortex surface 2115 is smooth and slightly curved, releasing continuous vortices to peel off attachments. The transition surface 2114 of two adjacent variable-section blades is a twisted parabola, which gradually shrinks the flow channel between adjacent blades to prevent backflow. In the circumferential direction, several such blades are arranged at equal angles and staggered with each other to form a continuous spiral staircase, which is like the staggered blades of a fan and the spiral edge of a drill bit. They rotate synchronously, drawing in the sediment from the outer edge, breaking it layer by layer, and pushing it upward along the conical channel, eventually forming a strong upflow in the center, which is efficiently sucked in by the jet pump. The outer diameter of the outer spiral 211 formed by several variable-section blades matches the outer diameter of the suction port 231, and the inner crushing spiral is configured as several circumferentially arranged serrated protrusions, each of which includes a fixed end and a shearing end, and the shearing end is configured toward the center of the suction port 231.

[0067] In this embodiment, the outer spiral 211 adopts variable-section blades with large pitch and large lead angle (α1 = 35°-45°), which generate strong axial thrust through high-speed rotation (speed n1 = 1500-2500r / min), pushing large particles of impurities toward the throat, and at the same time forming a turbulent zone at the edge of the blade, destroying the agglomeration structure of the mud particles and reducing the fluid viscosity.

[0068] The inner crushing spiral performs secondary shearing and crushing on the sucked mud, impacting particles with a diameter of more than 50 mm to less than 20 mm, thereby avoiding clogging of the annular nozzle 43 and the throat.

[0069] Arrangement logic and flow field optimization of crushing and conveying mechanism 21:

[0070] Axial arrangement:

[0071] like Figure 6 As shown, there is a distance between the sediment to be sucked and the suction port 231 of the suction pipe 23, forming a pre-acceleration zone to prevent the spiral blades from directly contacting the sediment and causing wear.

[0072] The crushing and conveying mechanism 21 simultaneously performs the triple functions of particle crushing, swirl acceleration, and negative pressure enhancement.

[0073] The suction pipe 11 is provided with a drag reduction mechanism 3, which is located near the intersection of the two sets of rotatable suction arms 2. Figure 7As shown, the drag reduction mechanism 3 includes a portion located near the intersection of the two sets of rotatable suction arms 2. The drag reduction mechanism 3 includes an air inlet 31, an air inlet ring 32, and several streamlined air outlets arranged in a ring on the air inlet ring 32. The air inlet angle of the air outlet is between 12° and 18°. In this embodiment, an air inlet angle of 15° is preferred. The air outlet profile adopts a three-segment continuous transition from "teardrop" to "ellipse" to "straight line": the inlet section is a semi-ellipse with the major axis facing forward, the middle section gradually transforms into a symmetrical teardrop curve, and the outlet section slightly expands in a straight line with a 0.5° expansion angle. The radius of curvature changes continuously throughout, with no inflection points, and no airflow separation along the entire length. In this embodiment, the drag reduction mechanism 3 is provided with a total of six air outlets, symmetrically distributed vertically and horizontally on the air inlet ring 32. The air inlet ring 32 is disposed on the wall of the suction pipe 11, at the rear end of the intersection of the two suction arms. The air outlets penetrate the pipe to deliver gas into the pipe. Because the sucked fluids converge in this area, the suction pipe 11 experiences severe disturbances. A drag-reducing mechanism 3 is installed here to mitigate the increased drag losses caused by friction between solid particles and between particles and the pipe wall. The aeration drag-reduction mechanism is as follows: after gas is added, a thin gas film forms around the pipe wall as the fluid flows through the pipe, replacing the boundary layer thickness. This changes the boundary layer's mass density, viscosity, and velocity gradient, reducing the shear stress on the wall within the boundary layer and thus reducing transport resistance. Furthermore, aeration alters the turbulence intensity of the fluid within the pipe, allowing small bubbles to infiltrate between particles, between flow layers, and between the fluid and the pipe wall. This reduces direct collisions between particles and reduces friction between the pipe wall and the particles, further reducing pipeline transport resistance.

[0074] The drag reduction mechanism 3 injects air into the fluid to form a gas-liquid mixture, thereby reducing the density of the fluid, reducing the viscosity and resistance of the fluid, making it easier for large particles of impurities to be rolled up and enter the suction pipe 23, significantly reducing the risk of blockage. The drag reduction mechanism 3 can enhance the suction efficiency. The gas-liquid mixture forms a stronger negative pressure area at the suction port, enhancing the suction force, making it easier for the fluid to be drawn into the pipeline, while reducing the required suction power and energy consumption. In addition, the relatively fast flow rate of the gas-liquid mixture in the pipeline can reduce the impact and wear of solid particles in the fluid on the inner wall of the pipeline, thereby extending the service life of the equipment and reducing maintenance costs.

[0075] This embodiment uses computational fluid dynamics (CFD) simulation to determine the optimal angle range (12°-18°) of the air outlet, so that the airflow can be evenly distributed and form a stable air film. This embodiment adopts an air inlet angle of 15°. This angle design enables high-pressure gas to be injected into the mud flow channel with an ideal diffusion gradient, and builds a continuous and uniform air film buffer layer between the mud and the pipe wall, effectively reducing the wall friction of the mud flow. The air outlet adopts a streamlined design, which eliminates the turbulent separation phenomenon when the air flow enters, allowing the gas to smoothly transition to the mud flow field in a laminar state, further improving the stability and energy utilization efficiency of the gas-liquid two-phase flow. Compared with traditional circular or rectangular air outlets, streamlined air outlets can more effectively guide the airflow and reduce the contraction and expansion losses of the airflow.

[0076] like Figure 8 As shown in the figure, numerical simulations show that by adjusting the air addition rate, the equipment can flexibly handle slurries of varying concentrations and particle sizes, improving adaptability and further optimizing the suction process. Drag reduction mechanism 3 also reduces environmental impact by optimizing the suction process, reducing energy consumption, and lowering noise and vibration during operation, making the equipment more environmentally friendly.

[0077] In summary, the device achieves low noise and energy conservation through three key environmental optimization features: First, the streamlined air outlet, combined with the air film buffer layer, reduces mechanical friction between the slurry and the pipeline. Second, the aeration system avoids the energy waste caused by over-pressurization in traditional suction equipment. Finally, the stable gas-liquid two-phase flow reduces pipeline vibration, extends equipment life, and reduces maintenance waste, meeting the development needs of green engineering technology.

[0078] The annular jet pump body 1 also includes a suction chamber 14, which is connected to the output end of the suction pipe 11. The upper end of the suction chamber 14 is provided with a working fluid inlet 13 connected to the suction chamber 14. A movable nozzle 4 is provided in the suction chamber 14, and the movable nozzle 4 can move back and forth horizontally in the suction chamber 14. The output end of the suction chamber 14 is connected to a movable throat pipe 5, and the length of the movable throat pipe 5 is adjustable. The output end of the movable throat pipe 5 is connected to a diffuser, and the discharge pipe 12 is connected to the output end of the diffuser.

[0079] like Figure 9As shown, the movable throat pipe 5 includes a hydraulic rod 52, a first throat pipe 51, and a second throat pipe 53. The first throat pipe 51 is fixedly connected to the outlet of the suction chamber 14, and the second throat pipe 53 is nested outside the first throat pipe 51 and fixedly connected to the diffuser. One end of the hydraulic rod 52 is fixed at the outlet of the suction chamber 14, and the other end of the hydraulic rod 52 is fixed on the second throat pipe 53. The extension and retraction of the hydraulic rod 52 drives the second throat pipe 53 away from or closer to the outlet of the suction chamber 14. The extension and retraction of the hydraulic rod 52 drives the two nested first throat pipes 51 and second throat pipes 53 to extend and retract, thereby changing the throat pipe length. The throat pipe length is also a major factor affecting the suction performance.

[0080] like Figure 10 As shown, the movable nozzle 4 includes a nozzle movement motor 41, a tooth groove 42, and an annular nozzle 43. The nozzle movement motor 41 is fixed to both sides of the suction chamber 14, and the tooth grooves 42 are embedded on both sides of the annular nozzle 43 and are symmetrically distributed. The output end of the nozzle movement motor 41 engages with the tooth groove 42. The output end of the nozzle movement motor 41 rotates, driving the tooth groove 42 to move, and further driving the annular nozzle 43 to move. When the movable nozzle 4 moves, it will change the suction angle of the working fluid entering the suction chamber 14, the distance between the nozzle and the throat, and the area ratio of the nozzle outlet to the throat, thereby affecting the suction performance of the jet pump. Therefore, the movement of the annular nozzle 43 can be controlled to adjust the suction performance of the jet pump.

[0081] This embodiment also includes an intelligent monitoring and calculation system: intelligent monitors are set at the suction pipe 11, the nozzle outlet, and the discharge pipe 12. By real-time monitoring of the cross-sectional flow and pressure at these three locations, the ratio of the mass flow of the sucked fluid to the mass flow of the working fluid, the ratio of the pressure rise to the pressure of the working fluid, and the real-time performance data are obtained to adjust to a more optimal suction angle and throat length. Specifically, this embodiment automatically adjusts the operating parameters of the equipment to achieve the best suction effect by real-time monitoring and analysis of equipment operating data. By learning a large amount of historical data and real-time monitoring data, the neural network can predict the optimal operating parameters of the equipment under different working conditions. Specific applications are as follows:

[0082] Data collection and preprocessing: High-precision sensors 6 are installed at key locations on the equipment to collect real-time data such as flow, pressure, and temperature. After preprocessing, this data is fed into the neural network.

[0083] Model training and optimization: The neural network model is trained using a large amount of historical data to learn the optimal operating parameters under different operating conditions. The trained model can predict the optimal operating parameters of the equipment based on real-time data.

[0084] Real-time Adjustment and Feedback: The output of the neural network model is directly used to adjust the equipment's operating parameters, such as nozzle position, throat length, and gas volume. During equipment operation, real-time monitoring data is continuously fed back into the neural network, and the model dynamically adjusts based on this feedback to ensure the equipment always operates at its optimal state.

[0085] 1. Calculation of flow ratio q: mass flow rate of the sucked fluid The working fluid mass flow is measured by the flow sensor 6 at the suction pipe 11; Measured by the flow sensor 6 at the nozzle outlet; the flow ratio q is calculated as:

[0086] 2. Calculation of pressure ratio p: The pressure rise ΔP is the difference between the pressure at the discharge pipe 12 and the pressure at the suction pipe 11; the working fluid pressure Pp is the pressure at the nozzle outlet; the pressure ratio p is calculated as follows:

[0087] 3. Calculation of efficiency η:

[0088] Example 2

[0089] like Figures 11-12 A suction method includes the suction jet pump of Example 1, wherein a turbine flowmeter and a high-temperature pressure sensor 6 are provided at the outlet of the movable nozzle 4 to monitor the flow rate Qp and pressure Pp of the working fluid with a data accuracy of 0.1 and a response time of less than 200ms. An ultrasonic flowmeter and a differential pressure transmitter are provided on the discharge pipe 12 to measure the discharge flow velocity vd and the pressure difference ΔP = Pd - Ps, and to simultaneously calculate the volume flow rate and pressure rise value.

[0090] The above-mentioned suction method comprises the following steps:

[0091] 1: Based on the predetermined suction direction, adjust the angles of the two suction arms to align them with the target suction area. The outer spiral 211 rotates to generate axial thrust, pushing large impurities toward the throat. Simultaneously, a turbulent zone is formed at the edge of the outer spiral 211, breaking up the agglomerated structure of the mud particles and reducing fluid viscosity. The inner crushing spiral performs secondary shearing on the sucked-in mud, reducing particles larger than 50 mm to less than 20 mm, thus preventing blockage of the annular nozzle 43 and the throat.

[0092] 2: During the suction process, the drag reduction mechanism 3 is activated, the air outlet is opened, and an appropriate amount of air is injected into the fluid to form a gas-liquid mixture. An electromagnetic flowmeter and a piezoresistive pressure sensor 6, located at the rear end of the drag reduction mechanism 3 near the suction chamber 14, collect the flow rate Qs and static pressure Ps of the sucked fluid in real time, transmitting at least 10 sets of data per second to the intelligent monitoring and computing system.

[0093] 3: During the suction process, the intelligent monitoring and calculation system operates synchronously, monitoring the cross-sectional flow rate and pressure at the suction pipe 11, the annular nozzle 43 outlet, and the discharge pipe 12 in real time. Based on this data, the intelligent monitoring and calculation system automatically calculates performance parameters such as the ratio of the suction fluid mass flow rate to the working fluid mass flow rate (q = Qs / Qp), the ratio of the pressure rise to the working fluid pressure (p = ΔP / Pp), and the efficiency (η = q·p). This data is displayed synchronously on the user interface and stored in the local database, forming a historical trend curve. Based on this real-time performance data, the variable nozzle system in the suction chamber 14 and the throat length control system are automatically adjusted.

[0094] Furthermore, in the variable nozzle system of the suction chamber 14, the encoder achieves nozzle position accuracy control of ±0.5mm; when q<0.8 or η<60%, the nozzle moves toward the throat and reduces the suction angle (adjusted by 5° each time) until q returns to the range of 0.9-1.1; if q=0.6, it is adjusted quickly at the set maximum speed; if q=0.75, it is fine-tuned at the set low speed.

[0095] In the throat length control system, the hydraulic system response time is less than 1s. When p is less than 0.3 or the pressure fluctuation of the discharge pipe 12 is greater than ±15%, the hydraulic cylinder extends the throat by 20-50mm each time until p stabilizes at 0.4-0.6; if Qs continues to be high, the throat length is prioritized to maintain the lower limit value to avoid excessive extension and fluid retention.

[0096] In the actual operation process, thorough preparation is required before implementation. First, conduct a comprehensive inspection of the entire jet pump to ensure that all components are intact and securely connected. Based on the scale of the specific project and the seabed soil conditions, select an appropriate suction arm length and initial throat length for assembly. For example, for small projects, a shorter suction arm and throat length can be selected to improve operational flexibility. For large projects, the length can be increased to expand the suction range and enhance suction capacity. Furthermore, it is necessary to ensure that the sensor 6 and control unit in the intelligent monitoring and computing system are functioning properly, and calibrate the sensor 6 to accurately measure parameters such as flow rate and pressure. Furthermore, a detailed survey of the operation area should be conducted to understand the seabed topography, soil quality, water depth, and the presence of large particles. Based on this survey, the optimal installation location and suction direction of the jet pump should be determined. Warning signs should be placed around the operation area to ensure operational safety. Finally, arrange the power supply and piping system as needed, connect the jet pump to the power source and mud delivery pipeline, and ensure that the joints are securely sealed and leak-free.

[0097] After the equipment is started, initial parameter settings are required. First, activate the suction arm rotation system, aligning the two suction arms with the initial position. Adjust the angle of the suction arms according to the predetermined suction direction, aligning them with the target suction area. Next, activate the crushing and conveying mechanism 21 to observe whether it rotates smoothly and whether there are any abnormal noises or vibrations. Initially adjust the rotation speed of the crushing and conveying mechanism 21 based on the mud concentration and particle size. Generally, begin suction at a medium speed, and subsequently fine-tune it based on actual suction conditions. Then, activate the drag reduction mechanism 3, open the air outlet, and inject an appropriate amount of air into the fluid to form a gas-liquid mixture. Observe the flow of the gas-liquid mixture in the pipeline and adjust the air intake to ensure smooth fluid flow within the pipeline, reducing resistance while ensuring that the gas-liquid mixture can effectively pick up large impurities and carry them into the suction pipe 23. Finally, activate the jet pump, injecting the working fluid into the mixing chamber through the annular nozzle 43, creating a negative pressure zone, and begin suctioning the mud. The variable nozzle system and throat length control system of the suction chamber 14 are preliminarily set up. According to experience or estimated suction conditions, the suction angle of the nozzle and the throat length are adjusted to a suitable initial value. For example, the suction angle is set to about 30 degrees and the throat length is set to a medium length.

[0098] The above-described embodiments of the present invention do not limit the scope of protection of the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the claims of the present invention.

Claims

1. A suction jet pump, characterized in that: The invention comprises an annular jet pump body (1) for providing power for suction, the annular jet pump body (1) comprising a suction pipe (11) and a single discharge pipe (12), the inlet end of the suction pipe (11) being provided with two groups of symmetrically arranged rotatable suction arms (2), synchronous suction on both sides of the interior of the groove being achieved by the two groups of rotatable suction arms (2), adjustment of the suction position as well as crushing and conveying of seabed slurry being achieved by the rotatable suction arms (2), and uniform discharge of the sucked seabed slurry through the single discharge pipe (12); The rotatable suction arm (2) comprises: a rotation drive mechanism (24), a suction pipe (23), a crushing and conveying drive mechanism (22) and a crushing and conveying mechanism (21); the suction pipe (23) is connected to the suction pipe (11) via the rotation drive mechanism (24), and the rotation drive mechanism (24) drives the suction pipe (23) to swing forward and backward or left and right; the crushing and conveying mechanism (21) is arranged at the suction inlet of the suction pipe (23), and comprises an outer spiral (211) and an inner spiral (212) arranged inside the outer spiral (211); the crushing and conveying drive mechanism (22) drives the inner spiral (212) inside the outer spiral (211) to rotate synchronously, thereby achieving seabed slurry particle crushing, vortex acceleration and negative pressure enhancement.

2. A suction jet pump according to claim 1, characterized in that: The rotation drive mechanism (24) includes a front and rear drive motor (241), a gear I (242), a gear ring I (243), a left and right drive motor (244), a gear II (245) and a gear ring II (246). The front and rear drive motor (241) is arranged on the outer wall of the suction pipe (11) and is connected to the gear ring I (243) through the gear I (242). The gear ring I (243) is arranged at the inlet end of the suction pipe (11); the gear ring I (243) is connected to the gear ring II (246) through the connecting elbow (25), and the suction pipe (11) and the suction pipe (23) are connected through the connecting elbow (25). The gear ring II (246) is connected to the left and right drive motors (244) through the gear II (245). The left and right drive motors (244) are arranged on the side wall of the connecting elbow (25).

3. The suction jet pump according to claim 1, characterized in that: The suction port (231) of the suction pipe (23) is configured as a trumpet-shaped structure. The crushing and conveying drive mechanism (22) comprises a crushing and conveying motor (221), a gear III (222) and a gear ring III (223). The gear III (222) is vertically arranged and connected to the output end of the crushing and conveying motor (221). The gear ring III (223) is horizontally arranged on the inner wall of the suction port (231) and meshes with the gear III (222). The outer spiral (211) is fixed on the lower surface of the gear ring III (223), and the inner spiral (212) is nested at the upper end of the inner side of the outer spiral (211).

4. A suction jet pump according to claim 3, characterized in that: The outer spiral (211) is configured as a plurality of variable-section blades arranged circumferentially at intervals, the outer diameter of the outer spiral (211) formed by the plurality of variable-section blades matches the outer diameter of the suction port (231), and the inner crushing spiral is configured as a plurality of circumferentially arranged sawtooth-shaped protrusions, the sawtooth-shaped protrusions including a fixed end and a shearing end, the shearing end being arranged toward the center of the suction port (231).

5. A suction jet pump according to claim 4, characterized in that: The variable-section blade comprises a suction surface (2111), a leading edge cutting surface (2112), a pressure surface (2113), a transition surface (2114) and a trailing edge vortex surface (2115), which are arranged in sequence in a clockwise direction; the suction surface (2111) is arranged as an inwardly concave arc surface, and the pressure surface (2113) is arranged as an outwardly convex arc surface; the leading edge cutting surface (2112) is arranged between the suction surface (2111) and the pressure surface (2113) and connects the suction surface (2111) and the pressure surface (2113); the trailing edge vortex surface (2115) is arranged on one side of the suction surface (2111) and is arranged to be smooth with an arc; the two transition surfaces (2114) of adjacent variable-section blades are arranged as a twisted parabola structure.

6. The suction jet pump according to claim 1, characterized in that: The suction pipe (11) is provided with a drag reduction mechanism (3), the drag reduction mechanism (3) being close to the intersection of the two groups of rotatable suction arms (2), the drag reduction mechanism (3) comprising an air inlet (31), an air inlet ring (32) and a plurality of streamlined air outlets arranged in an annular pattern on the air inlet ring (32), the air inlet angle of the air outlet being 12° to 18°.

7. The suction jet pump according to claim 1, characterized in that: The annular jet pump body (1) includes a suction chamber (14), the suction chamber (14) being connected to the output end of the suction pipe (11); a working fluid inlet (13) being connected to the suction chamber (14) is provided at the upper end of the suction chamber (14); a movable nozzle (4) is provided in the suction chamber (14), and the movable nozzle (4) can move horizontally back and forth in the suction chamber (14); the output end of the suction chamber (14) is connected to a movable throat pipe (5), the length of the movable throat pipe (5) being adjustable; the output end of the movable throat pipe (5) is connected to a diffusion pipe, and the discharge pipe (12) is connected to the output end of the diffusion pipe.

8. The suction jet pump according to claim 7, characterized in that: The movable nozzle (4) comprises a nozzle moving motor (41), a tooth groove (42) and an annular nozzle (43); the nozzle moving motor (41) is fixed on both sides of the suction chamber (14); the tooth groove (42) is embedded on both sides of the annular nozzle (43) and is symmetrically distributed on both sides; the output end of the nozzle moving motor (41) is engaged with the tooth groove (42); the output end of the nozzle moving motor (41) rotates, driving the tooth groove (42) to move, and further driving the annular nozzle (43) to move; The movable throat pipe (5) comprises a hydraulic rod (52), a first throat pipe (51) and a second throat pipe (53). The first throat pipe (51) is fixedly connected to the outlet of the suction chamber (14). The second throat pipe (53) is nested outside the first throat pipe (51) and fixedly connected to the diffuser. One end of the hydraulic rod (52) is fixed at the outlet of the suction chamber (14), and the other end of the hydraulic rod (52) is fixed on the second throat pipe (53). The extension and retraction of the hydraulic rod (52) drives the second throat pipe (53) away from or close to the outlet of the suction chamber (14).

9. A suction method, characterized in that: The invention comprises a suction jet pump according to any one of claims 1 to 8, wherein a turbine flowmeter and a high-temperature pressure sensor (6) are provided at the outlet of the movable nozzle (4) to monitor the flow rate Qp and pressure Pp of the working fluid, with a data accuracy of 0.1 and a response time of less than 200ms; an ultrasonic flowmeter and a differential pressure transmitter are provided at the discharge pipe (12) to measure the discharge flow rate vd and the pressure difference ΔP=Pd-Ps, and to synchronously calculate the volume flow rate and the pressure rise value; The suction method includes the following steps: 1: According to the predetermined suction direction, the angles of the two sets of suction arms are adjusted so as to align them with the target suction area; the outer spiral (211) rotates to generate axial thrust, pushing large particles of impurities toward the throat, while forming a turbulent zone at the edge of the outer spiral (211), destroying the agglomerated structure of the mud particles and reducing the fluid viscosity; the inner crushing spiral performs secondary shear crushing on the sucked mud, impacting particles with a diameter of more than 50 mm to less than 20 mm, thereby avoiding clogging of the annular nozzle (43) and the throat; 2: During the suction process, the drag reduction mechanism (3) is synchronously activated, the air outlet is opened, and an appropriate amount of air is injected into the fluid to form a gas-liquid mixture; the electromagnetic flowmeter and the piezoresistive pressure sensor (6) are arranged at the rear end of the drag reduction mechanism (3) near the suction chamber (14), and the flow rate Qs and static pressure Ps of the sucked fluid are collected in real time, and at least 10 sets of data are transmitted per second to the intelligent monitoring and computing system; 3: During the suction process, the intelligent monitoring and calculation system works synchronously to monitor the cross-sectional flow and pressure at the suction pipe (11), the outlet of the annular nozzle (43), and the discharge pipe (12) in real time; the intelligent monitoring and calculation system automatically calculates the performance parameters such as the ratio of the mass flow of the sucked fluid to the mass flow of the working fluid q=Qs / Qp, the ratio of the pressure rise to the pressure of the working fluid p=ΔP / Pp, and the efficiency η=q·p based on the monitored data; the data is synchronously displayed on the operation interface and stored in the local database to form a historical trend curve; based on the real-time performance data, the suction chamber (14) variable nozzle system and the throat length control system are automatically adjusted; in the suction chamber (14) variable nozzle system, the encoder realizes the nozzle position accuracy of ±0.5mm control; when q<0.8 or η<60%, the nozzle moves toward the throat and reduces the suction angle until q returns to the range of 0.9-1.1; if q=0.6, it is quickly adjusted at the set maximum speed; if q=0.75, it is fine-tuned at the set low speed; In the throat length control system, the hydraulic system response time is less than 1s. When p<0.3 or the pressure fluctuation of the discharge pipe (12) is greater than ±15%, the hydraulic cylinder extends the throat by 20-50mm each time until p stabilizes at 0.4-0.

6. If Qs continues to be high, the throat length is maintained at the lower limit value to avoid excessive extension and fluid retention.

10. A trenching machine, characterized in that: The body of the trenching machine is provided with a suction jet pump according to any one of claims 1 to 8.

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