A slurry pump cleaning mechanism for a shield machine

Abstract

The present invention discloses a mud pump cleaning mechanism for a shield machine, which relates to the technical field of mud pumps and includes a cleaning ring arranged between a water-blocking ring and a sealing structure, wherein a spiral guide groove is provided on the inner side of the cleaning ring, wherein the spiral guide groove is arranged around the outer circumference of the plunger, and the inlet of the spiral guide groove is connected to a water inlet pipe tangent to the spiral guide groove, wherein the water inlet pipe passes through a stuffing box and a plunger sleeve, and the outlet of the spiral guide groove is connected to a water outlet pipe tangent to the spiral guide groove, wherein the water outlet pipe passes through the stuffing box and the plunger sleeve. The present invention overcomes the pain points of low cleaning efficiency, high particle residue, and frequent maintenance of traditional technologies through the directional swirl of the spiral guide groove, dynamic pressure regulation, and structural innovation, thereby providing an efficient, reliable, and durable cleaning solution for the mud pump of a shield machine.

Description

Technical Field

[0001] The invention relates to the technical field of mud pumps, in particular to a mud pump cleaning mechanism of a shield machine. Background Art

[0002] Plunger pumps face challenges in shield machine slurry transportation, including high abrasion and particle penetration into sealing areas. While existing technologies offer a variety of cleaning and isolation solutions, they all have limitations:

[0003] Chinese invention patent publication number CN119435374A uses high-pressure clean water circulation to clean the plunger surface and achieves seal monitoring through three-stage filtration and turbidity sensors. However, it relies on a passive annular water flow ring design, and the dispersed water flow causes pressure attenuation, making it difficult to completely remove hard particles (such as quartz sand). In addition, the circulation system structure is complex and the maintenance cost is high.

[0004] China Utility Model Authorization Announcement No. CN222315347U uses a dynamic clean water isolation zone to prevent particles from entering the seal, but it relies on the switching of the suction / drainage stroke to update the isolation water. Under the continuous high-pressure working conditions of the shield machine, frequent isolation zone updates may cause water flow pressure fluctuations, unstable isolation effect, and the multi-stage water storage tank structure occupies a large space.

[0005] China Utility Model Authorization Announcement No. CN209414137U uses oil medium circulation to clean coal slurry particles. Although it can extend the life of the oil through cooling and filtration, the oil system is easily contaminated in the mud environment, maintenance is complicated, and the viscosity characteristics of the oil may reduce the efficiency of flushing tiny particles.

[0006] The above technologies may have problems such as dispersed cleaning pressure, structural redundancy, or reliance on specific media (such as oil), resulting in limited applicability. They are unable to meet the dual needs of efficient cleaning and sealing protection of the plunger surface under extreme working conditions of shield machines (high pressure, high abrasion, and continuous operation). Summary of the Invention

[0007] The object of the present invention is to provide a slurry pump cleaning mechanism for a shield machine to solve the problems raised in the above background technology.

[0008] In order to achieve the above-mentioned object of the invention, the present invention adopts the following technical solutions:

[0009] The present invention provides a mud pump cleaning mechanism for a shield machine, which is arranged in a stuffing box of a plunger sleeve, wherein a water-blocking ring and a sealing structure are provided in the stuffing box, and the mud pump cleaning mechanism includes a cleaning ring arranged between the water-blocking ring and the sealing structure, a spiral guide groove is opened on the inner side of the cleaning ring, and the spiral guide groove is arranged around the outer circumference of the plunger, and the inlet of the spiral guide groove is connected to a water inlet pipe tangent to the spiral guide groove, and the water inlet pipe passes through the stuffing box and the plunger sleeve, and the outlet of the spiral guide groove is connected to a water outlet pipe tangent to the spiral guide groove, and the water outlet pipe passes through the stuffing box and the plunger sleeve.

[0010] Furthermore, the width of the spiral guide groove gradually increases from the inlet to the outlet, and the cross section of the spiral guide groove is trapezoidal.

[0011] Furthermore, the bottom of the spiral guide groove is evenly arrayed with guide fins, and the inner wall of the spiral guide groove and the surface of the guide fins are covered with a tungsten carbide-based wear-resistant coating with a coating thickness of 0.1-0.3 mm and a hardness ≥HRC65.

[0012] Furthermore, the height of the guide fin gradually decreases from the inlet to the outlet of the spiral guide groove, with a height difference of 0.5-1.2 mm. The leading edge of the guide fin is an acute angle structure, and its leading edge acute angle forms an angle of 15°-20° with the mainstream direction, and the trailing edge of the guide fin is a circular arc transition.

[0013] Furthermore, a sealing gasket is embedded in the spiral edge of the spiral guide groove close to the sealing structure. The sealing gasket includes a spiral sealing strip arranged along the spiral edge of the spiral guide groove and a transverse sealing strip connected between the two ends of the spiral sealing strip.

[0014] Furthermore, a micro pressure sensor is integrated in the water inlet pipe, and the pressure sensor is connected to the controller signal for real-time monitoring of the inlet pressure of the spiral guide groove and dynamically adjusting the water inlet flow rate.

[0015] Furthermore, a hemispherical pit is provided at the bottom of the spiral guide groove, with a diameter of 0.5-1 mm and a depth of 0.2-0.5 mm.

[0016] Furthermore, a backwash interface is provided on the water outlet pipe, and the backwash interface is connected to an external high-pressure water source through a switching valve; the switching valve is configured to: connect the water inlet pipe with the spiral guide groove or close the water inlet pipe and connect the backwash interface with the spiral guide groove.

[0017] Compared with the existing technology, one or more of the above technical solutions have the following beneficial effects:

[0018] 1. This invention utilizes a spiral guide trough and optimized fluid dynamics to allow the cleaning fluid to enter the trough tangentially from its inlet, thereby forming a unidirectional, high-speed vortex. This vortex propels along the plunger surface, creating a uniform, closed-loop flushing layer. Compared to traditional annular water rings, the spiral path prevents water flow dispersion, concentrating pressure on the plunger surface and increasing shear force, effectively removing adherent particles (such as clay and quartz sand). Furthermore, the centrifugal force generated during the vortex propulsion drives the removed particles outward. Combined with the gradually expanding flow path design of the trapezoidal guide trough (where the width gradually increases from inlet to outlet), this further optimizes pressure distribution and reduces the risk of particle re-adsorption. Furthermore, the hemispherical indentations at the trough bottom induce localized turbulence, disrupting the laminar flow boundary of the slurry and enhancing the removal efficiency of micron-sized particles.

[0019] 2. This invention integrates a micro pressure sensor and controller into the water inlet pipe to monitor the inlet pressure in real time and dynamically adjust the flow rate. When increased resistance (such as accumulation of hard particles) is detected, the water inlet pressure is immediately increased. If the flow channel is blocked, the switching valve activates the reverse flush mode, and the reverse high-pressure water flow directly impacts the sediment, which is more adaptable.

[0020] 3. This invention combines guide fins with a tungsten carbide-based wear-resistant coating to split high-speed fluid into multiple controllable streams, forming high-frequency microjets that penetrate the cavitation layer. The coating's hardness, ≥HRC65, withstands long-term, high-pressure, alternating loads. The dovetail joint structure of the spiral and transverse sealing strips prevents axial leakage and enhances sealing performance.

[0021] In summary, the present invention overcomes the pain points of low cleaning efficiency, high particle residue and frequent maintenance of traditional technologies through the directional swirl, dynamic pressure regulation and structural innovation of the spiral guide groove, and provides an efficient, reliable and durable cleaning solution for the shield machine mud pump.

[0022] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawings, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0024] Figure 1 It is a schematic diagram of the internal structure of the mud pump of the present invention;

[0025] Figure 2 This is a schematic structural diagram of the plunger sleeve of the mud pump of the present invention;

[0026] Figure 3 yes Figure 2 Schematic diagram of the cross-sectional plan structure;

[0027] Figure 4 This is a schematic structural diagram of the cleaning ring of the present invention from a first perspective;

[0028] Figure 5 yes Figure 4 Schematic diagram of the local structure at A;

[0029] Figure 6 This is a schematic structural diagram of the cleaning ring of the present invention from a second viewing angle.

[0030] In the picture:

[0031] 1- plunger sleeve; 11- stuffing box; 111- water blocking ring; 112- sealing structure; 2- cleaning ring; 21- spiral guide groove; 22- water inlet pipe; 23- water outlet pipe; 3- guide fin; 4- sealing gasket; 41- spiral sealing strip; 42- transverse sealing strip; 6- reverse flushing interface; 61- switching valve; 7- plunger. DETAILED DESCRIPTION

[0032] In order to enable those skilled in the art to better understand the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in 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. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of this application.

[0033] See also Figures 1-6 The present invention provides a mud pump cleaning mechanism for a shield machine, which is arranged in a stuffing box 11 of a plunger sleeve 1, wherein a water-blocking ring 111 and a sealing structure 112 are provided in the stuffing box 11, and the mud pump cleaning mechanism includes a cleaning ring 2 arranged between the water-blocking ring 111 and the sealing structure 112, wherein a spiral guide groove 21 is provided on the inner side of the cleaning ring 2, wherein the spiral guide groove 21 is arranged around the outer circumference of the plunger 7, and the inlet of the spiral guide groove 21 is connected to a water inlet pipe 22 tangent to the spiral guide groove 21, wherein the water inlet pipe 22 passes through the stuffing box 11 and the plunger sleeve 1, and the outlet of the spiral guide groove 21 is connected to a water outlet pipe 23 tangent to the spiral guide groove 21, wherein the water outlet pipe 23 passes through the stuffing box 11 and the plunger sleeve 1.

[0034] Working principle: When in use, high-pressure cleaning fluid (usually clean water or liquid containing detergent) enters the spiral guide groove 21 in a tangential direction through the water inlet pipe 22 to form a unidirectional high-speed vortex, and the vortex spirally propels along the surface of the plunger 7 to form a uniform closed-loop flushing layer on the surface of the plunger 7; unlike the diversion design of the traditional annular water ring, the spiral path avoids the dispersion of the water flow, so that the pressure is concentrated on the surface of the plunger 7, and the ability to strip mud particles on the surface of the plunger 7 is enhanced; and the vortex also generates turbulence and centrifugal force during the propulsion process, among which the turbulence further enhances the ability to strip mud particles on the surface of the plunger 7, and the centrifugal force can make the stripped particles migrate outward, reducing the risk of particle re-adsorption due to the reciprocating motion of the plunger 7.

[0035] Through the fluid dynamics design of the spiral guide trough 21, this invention converts the kinetic energy of the high-pressure water flow into a dual effect of directional swirl and centrifugal slag removal, significantly improving flushing efficiency and particle management capabilities. Compared to traditional passive isolation or dispersed circulation solutions, this method offers advantages in concentrated pressure, active flushing, and a compact structure, making it particularly suitable for extreme working conditions such as shield machines.

[0036] Furthermore, the width of the spiral guide groove 21 gradually increases from the inlet to the outlet, and the cross section of the spiral guide groove 21 is trapezoidal, with the upper base of the trapezoidal cross section of the spiral guide groove 21 facing the plunger 7 .

[0037] Through the gradually expanding flow channel and trapezoidal cross-section design of the spiral guide groove 21, when the high-pressure cleaning liquid is injected tangentially from the inlet, the gradually expanding flow channel structure optimizes the pressure distribution by gradually expanding the cross-sectional area while maintaining the axial propulsion power, thereby reducing energy loss; and the upper bottom edge of the trapezoidal cross-section is in close contact with the surface of the plunger 7, concentrating the fluid kinetic energy on the plunger 7 area, forming a strong wall-attaching impact shear force, and directly peeling off the attachments. Specifically, the upper layer (the upper bottom edge of the trapezoidal cross-section) of high-speed fluid is close to the surface of the plunger 7 to produce a high-gradient shear effect, effectively removing tiny particles; the lower layer (the upper bottom edge of the trapezoidal cross-section) of low-speed fluid expands outward along the trapezoidal slope, using the centrifugal effect to push large particles to migrate outward. The spirally propulsed tangential flow ensures that the surface of the plunger 7 is fully covered and flushed, and the axial flow provides continuous thrust, ultimately significantly reducing the accumulation of residues and maintaining long-term stable operation under extreme working conditions, completely solving the water flow dispersion and blockage problems of traditional structures.

[0038] Furthermore, the bottom of the spiral guide groove 21 is evenly arrayed with guide fins 3, and the inner wall of the spiral guide groove 21 and the surface of the guide fins 3 are covered with a tungsten carbide-based wear-resistant coating with a coating thickness of 0.1-0.3mm and a hardness ≥HRC65. The combination of the guide fins 3 evenly distributed at the bottom of the spiral guide groove 21 and the tungsten carbide-based wear-resistant coating further optimizes the flow field structure and improves the durability of the system. Specifically, the guide fins 3 are arranged at equal intervals along the spiral path, and their inclination angles form a specific angle with the mainstream direction, dividing the high-speed fluid originally concentrated in the center of the groove into multiple controllable tributaries, forcing the water flow to generate secondary vortices along the inclined surface of the fins, thereby enhancing the permeability to the irregular grooves on the surface of the plunger 7; at the same time, the narrow flow channels between the fins accelerate the local flow velocity, forming high-frequency microjets, which effectively penetrate the cavitation protection layer of the attachments. The tungsten carbide-based wear-resistant coating still maintains structural integrity when subjected to high-pressure alternating loads for a long time.

[0039] In an embodiment, the height of the guide fin 3 gradually decreases from the inlet to the outlet of the spiral guide groove 21, with a height difference of 0.5-1.2 mm. The leading edge of the guide fin 3 is an acute-angle structure, and its leading edge acute angle forms an angle of 15°-20° with the mainstream direction, and the trailing edge of the guide fin 3 is a circular arc transition.

[0040] In this embodiment, a sealing gasket 4 is embedded in the spiral edge of the spiral guide groove 21 near the sealing structure 112. The sealing gasket 4 includes a spiral sealing strip 41 arranged along the spiral edge of the spiral guide groove 21, and a transverse sealing strip 42 connected between the two ends of the spiral sealing strip 41. The spiral sealing strip 41 extends continuously along the spiral edge of the guide groove, and its cross-section has a dovetail-shaped shape and is embedded in the prefabricated groove. The transverse sealing strip 42 connects the two ends of the spiral sealing strip 41 via a wedge-shaped lock, forming a closed-loop seal with the end face of the plunger 7, blocking the axial leakage path and significantly improving the sealing reliability of the system under high-pressure pulsating conditions.

[0041] In this embodiment, a micro pressure sensor is integrated into the water inlet pipe 22. This pressure sensor is connected to the controller's signal signal and is used to monitor the inlet pressure of the spiral guide groove 21 in real time and dynamically adjust the inlet flow rate. When the mud pump is pumping out, hard particles (such as quartz sand) attached to the surface of the plunger 7 increase resistance. Once the sensor detects a pressure drop, the controller immediately increases the inlet flow rate, raising the inlet pressure. When the mud pump is pumping in, the sensor monitors pressure fluctuations and maintains the inlet pressure, forming a dynamic isolation barrier to prevent external particles from infiltrating the sealing area. If abnormal pressure fluctuations caused by seal wear are detected, the controller uses a PID algorithm to fine-tune the flow rate in real time to stabilize the isolation barrier.

[0042] In this embodiment, the bottom of the spiral guide groove 21 is provided with a hemispherical depression (not shown) with a diameter of 0.5-1 mm and a depth of 0.2-0.5 mm. When the high-pressure cleaning fluid flows through the depression, the hemispherical depression induces local turbulence, disrupting the laminar flow boundary of the slurry attached to the surface of the plunger 7 and enhancing the ability to remove micron-sized particles (such as clay and coal dust). The sudden change in the geometry of the depression edge generates high-gradient shear stress that directly impacts hard particles (such as quartz sand), improving cleaning efficiency. Simultaneously, the vortex formed within the depression suspends the exfoliated particles in the water flow, reducing the risk of secondary attachment. Combined with the gradually diverging flow path of the spiral guide groove 21 and the centrifugal force, the particles are guided along the trapezoidal slope to the tangent outlet pipe 23 for rapid discharge.

[0043] The pits are evenly distributed on the bottom of the trough and work together with the guide fins 3 to optimize the uniformity of the flow field and eliminate cleaning dead corners. Their tiny size avoids sudden pressure drops due to structural changes and maintains the stability of the flow field.

[0044] like Figure 6 As shown, in this embodiment, the outlet pipe 23 is provided with a backwash port 6, which is connected to an external high-pressure water source via a switching valve 61. The switching valve 61 is configured to connect the water inlet pipe 22 with the spiral guide groove 21 or to close the water inlet pipe 22 and connect the backwash port 6 with the spiral guide groove 21. In normal cleaning mode, the switching valve 61 opens the water inlet pipe 22, allowing the cleaning water to flow forward along the spiral direction of the spiral guide groove 21, flushing the mud and guiding it to the outlet pipe 23. When a blockage is detected or enhanced cleaning is required, the switching valve 61 immediately closes the water inlet pipe 22 and connects the backwash port 6 with the spiral guide groove 21. External high-pressure water is injected from the backwash port 6 into the spiral guide groove 21 in the opposite direction of the normal water flow, generating an impact force opposite to the direction of the normal water flow, directly destroying the mud agglomerates deposited between the spiral guide groove 21 and the guide fins 3.

[0045] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A slurry pump cleaning mechanism for a shield machine, arranged in a stuffing box (11) of a plunger sleeve (1), wherein a water blocking ring (111) and a sealing structure (112) are arranged in the stuffing box (11), characterized in that: The mud pump cleaning mechanism comprises a cleaning ring (2) arranged between a water-blocking ring (111) and a sealing structure (112), wherein a spiral guide groove (21) is provided on the inner side of the cleaning ring (2), wherein the spiral guide groove (21) is arranged around the outer circumference of the plunger (7), and the inlet of the spiral guide groove (21) is connected to a water inlet pipe (22) tangent to the spiral guide groove (21), wherein the water inlet pipe (22) passes through a stuffing box (11) and a plunger sleeve (1), and the outlet of the spiral guide groove (21) is connected to a water outlet pipe (23) tangent to the spiral guide groove (21), wherein the water outlet pipe (23) passes through the stuffing box (11) and the plunger sleeve (1); The width of the spiral guide groove (21) gradually increases from the inlet to the outlet, and the cross section of the spiral guide groove (21) is trapezoidal in shape, with the upper bottom edge of the trapezoidal cross section of the spiral guide groove (21) facing the plunger (7); The bottom of the spiral guide groove (21) is uniformly arrayed with guide fins (3), and the inner wall of the spiral guide groove (21) and the surface of the guide fins (3) are covered with a tungsten carbide-based wear-resistant coating with a coating thickness of 0.1-0.3 mm and a hardness of ≥HRC65; A sealing gasket (4) is embedded at the spiral edge of the spiral guide groove (21) on one side close to the sealing structure (112), and the sealing gasket (4) comprises a spiral sealing strip (41) arranged along the spiral edge of the spiral guide groove (21), and a transverse sealing strip (42) connected between the two ends of the spiral sealing strip (41).

2. The shield machine mud pump cleaning mechanism according to claim 1, characterized in that: The height of the guide fin (3) gradually decreases from the inlet to the outlet of the spiral guide groove (21), with a height difference of 0.5-1.2 mm. The leading edge of the guide fin (3) is an acute angle structure, and the acute angle of the leading edge forms an angle of 15°-20° with the mainstream direction. The trailing edge of the guide fin (3) is an arc transition.

3. The shield machine mud pump cleaning mechanism according to claim 1, characterized in that: A micro pressure sensor is integrated in the water inlet pipe (22), and the pressure sensor is connected to the controller signal for real-time monitoring of the inlet pressure of the spiral guide groove (21) and dynamically adjusting the water inlet flow rate.

4. The shield machine mud pump cleaning mechanism according to claim 1, characterized in that: The bottom of the spiral guide groove (21) is provided with a hemispherical pit with a diameter of 0.5-1 mm and a depth of 0.2-0.5 mm.

5. The shield machine mud pump cleaning mechanism according to claim 1, characterized in that: The water outlet pipe (23) is provided with a backwash interface (6), and the backwash interface (6) is connected to an external high-pressure water source via a switching valve (61); the switching valve (61) is configured to connect the water inlet pipe (22) with the spiral guide groove (21) or to close the water inlet pipe (22) and connect the backwash interface (6) with the spiral guide groove (21).

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