Slurry pump cleaning mechanism of shield tunneling machine

Abstract

The invention discloses a slurry pump cleaning mechanism of a shield tunneling machine, and relates to the technical field of slurry pumps, the slurry pump cleaning mechanism comprises a cleaning ring arranged between a water blocking ring and a sealing structure, the inner side of the cleaning ring is provided with a spiral flow guide groove, and the spiral flow guide groove is arranged around the peripheral surface of a plunger by one circle; an inlet of the spiral flow guide groove is connected with a water inlet pipe tangent to the spiral flow guide groove, the water inlet pipe penetrates through the stuffing box and the plunger sleeve, an outlet of the spiral flow guide groove is connected with a water outlet pipe tangent to the spiral flow guide groove, and the water outlet pipe penetrates through the stuffing box and the plunger sleeve. Through directional rotational flow of the spiral diversion trench, dynamic pressure regulation and control and structural innovation, the defects of low cleaning efficiency, more particle residues and frequent maintenance in the traditional technology are overcome, and an efficient, reliable and durable cleaning solution is provided for the shield tunneling machine slurry pump.

Description

Technical Field

[0001] The present invention relates to the technical field of slurry pumps, and particularly to a cleaning mechanism for the slurry pump of a shield machine. Background Art

[0002] Plunger pumps face the problems of high abrasion and particle infiltration into the sealing area during the slurry transportation of shield machines. Although various cleaning and isolation solutions are provided in the prior art, they all have limitations:

[0003] Chinese Patent Publication No. CN119435374A uses high-pressure clean water circulation to clean the plunger surface, and realizes seal monitoring through three-stage filtration and turbidity sensors. However, it relies on the passive annular water ring design, and the dispersed water flow leads to pressure attenuation, making it difficult to completely remove hard particles (such as quartz sand). Moreover, the circulation system has a complex structure and high maintenance costs.

[0004] Chinese Utility Model Authorization Publication No. CN222315347U prevents particles from entering the seal through a dynamic clean water isolation area. However, it relies on the switching of the suction / discharge stroke to update the isolation water. Under the continuous high-pressure working conditions of shield machines, the frequent update of the isolation area may cause water pressure fluctuations, resulting in unstable isolation effects, and the multi-stage water storage tank structure occupies a large space.

[0005] Chinese Utility Model Authorization Publication No. CN209414137U uses oil medium circulation to clean coal slurry particles. Although the oil life can be extended through cooling and filtration, the oil system is easily contaminated in the slurry environment, with complex maintenance, and the viscosity characteristics of the oil may reduce the scouring efficiency for tiny particles.

[0006] The above technologies either have dispersed cleaning pressure and redundant structures, or rely on specific media (such as oil), resulting in limited applicability, and it is difficult to meet the dual requirements of efficient cleaning of the plunger surface and seal protection under the extreme working conditions (high pressure, high abrasion, continuous operation) of shield machines. Summary of the Invention

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

[0008] To achieve the above invention purpose, the present invention adopts the following technical solutions:

[0009] A mud pump cleaning mechanism for a shield machine provided by the present invention is arranged in the stuffing box of the plunger sleeve. A water blocking ring and a sealing structure are arranged in the stuffing box. The mud pump cleaning mechanism includes a cleaning ring arranged between the water blocking ring and the sealing structure. A spiral diversion groove is formed on the inner side of the cleaning ring. The spiral diversion groove is arranged around the outer peripheral surface of the plunger for one week, and the inlet of the spiral diversion groove is connected with a water inlet pipe tangent to the spiral diversion groove. The water inlet pipe penetrates through the stuffing box and the plunger sleeve. The outlet of the spiral diversion groove is connected with a water outlet pipe tangent to the spiral diversion groove. The water outlet pipe penetrates through the stuffing box and the plunger sleeve.

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

[0011] Further, diversion fins are uniformly arranged in an array on the bottom of the spiral diversion groove, and a tungsten carbide-based wear-resistant coating is covered on the inner wall of the spiral diversion groove and the surface of the diversion fins. The coating thickness is 0.1 - 0.3 mm, and the hardness is ≥HRC65.

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

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

[0014] Further, a micro pressure sensor is integrated in the water inlet pipe. The pressure sensor is in signal connection with a controller and is used to monitor the inlet pressure of the spiral diversion groove in real time and dynamically adjust the water inlet flow rate.

[0015] Further, hemispherical pits are arranged on the bottom of the spiral diversion groove. The diameter of the pits is 0.5 - 1 mm, and the depth is 0.2 - 0.5 mm.

[0016] Further, a reverse flushing interface is arranged on the water outlet pipe. The reverse flushing interface is connected with an external high-pressure water source through a switching valve. The switching valve is configured to: connect the water inlet pipe with the spiral diversion groove or close the water inlet pipe, and connect the reverse flushing interface with the spiral diversion groove.

[0017] Compared with the prior art, the above one or more technical solutions have the following beneficial effects:

[0018] 1. Through the spiral flow guide groove and hydrodynamic optimization design, the cleaning liquid of the present invention can tangentially enter its interior from the inlet of the spiral flow guide groove, and thus form a unidirectional high-speed swirling flow. The swirling flow spirally advances along the surface of the plunger to generate a uniform closed-loop flushing layer. Compared with the traditional annular flowing water ring, the spiral path avoids the dispersion of water flow, and the pressure acts concentratedly on the surface of the plunger, enhancing the shear force and effectively stripping the adhered particles (such as clay and quartz sand). Moreover, during the spiral advancement of the swirling flow, the generated centrifugal force can drive the stripped particles to migrate outward. With the gradually expanding flow channel design of the trapezoidal cross-section flow guide groove (the groove width gradually increases from the inlet to the outlet), the pressure distribution is further optimized, reducing the risk of particle re-adsorption. At the same time, the hemispherical pits at the bottom of the groove induce local turbulence, which can disrupt the laminar boundary of the mud and enhance the removal efficiency of micron-sized particles.

[0019] 2. The present invention integrates a micro pressure sensor and a controller through the water inlet pipe to monitor the inlet pressure in real time and dynamically adjust the flow rate. When an increase in resistance (such as the accumulation of hard particles) is detected, the inlet water pressure is immediately increased; if the flow channel is blocked, the switching valve starts the reverse flushing mode, and the reverse high-pressure water flow directly impacts the sediment, with stronger adaptability.

[0020] 3. Through the combination of the guide fins and the tungsten carbide-based wear-resistant coating, the present invention divides the high-speed fluid into multiple controllable branch flows to form high-frequency micro jets that penetrate the cavitation layer. At the same time, the hardness of the coating is ≥HRC65, which can withstand long-term high-pressure alternating loads. The dovetail structure of the spiral sealing strip and the transverse sealing strip blocks the axial leakage and improves the sealing performance.

[0021] In summary, through the directional swirling flow, dynamic pressure regulation and structural innovation of the spiral flow guide groove, the present invention overcomes the pain points of the traditional technology, such as low cleaning efficiency, more particle residues and frequent maintenance, and provides an efficient, reliable and durable cleaning solution for the mud pump of the shield machine.

[0022] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The specification drawings forming a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention.

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

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

[0026] Figure 3 is Figure 2 a schematic cross-sectional plane structure diagram of

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

[0028] Figure 5 is Figure 4 A partial structural diagram of the A position of;

[0029] Figure 6 It is a schematic structural diagram of the second perspective of the cleaning ring of the present invention.

[0030] In the figure:

[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 - gasket; 41 - spiral sealing strip; 42 - transverse sealing strip; 6 - reverse flushing interface; 61 - switching valve; 7 - plunger. Specific embodiments

[0032] In order to enable those skilled in the art to better understand the solution of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0033] Please refer to Figures 1-6 , the present invention provides a mud pump cleaning mechanism for a shield machine, which is arranged in the stuffing box 11 of the plunger sleeve 1. A water blocking ring 111 and a sealing structure 112 are arranged in the stuffing box 11. The mud pump cleaning mechanism includes a cleaning ring 2 arranged between the water blocking ring 111 and the sealing structure 112. A spiral guide groove 21 is formed on the inner side of the cleaning ring 2. The spiral guide groove 21 is arranged around the outer peripheral surface of the plunger 7 for one week, and the inlet of the spiral guide groove 21 is connected with a water inlet pipe 22 tangent to the spiral guide groove 21. The water inlet pipe 22 penetrates through the stuffing box 11 and the plunger sleeve 1. The outlet of the spiral guide groove 21 is connected with a water outlet pipe 23 tangent to the spiral guide groove 21. The water outlet pipe 23 penetrates through the stuffing box 11 and the plunger sleeve 1.

[0034] Working principle: During use, the high-pressure cleaning liquid (usually clean water or a liquid containing a cleaning agent) enters the spiral diversion groove 21 tangentially through the water inlet pipe 22 to form a unidirectional high-speed swirl. The swirl advances spirally along the surface of the plunger 7 to form a uniform closed-loop flushing layer on the surface of the plunger 7. Different from the shunt design of the traditional annular flowing water ring, the spiral path avoids the dispersion of water flow, enables the pressure to act concentratedly on the surface of the plunger 7, and enhances the ability to peel off the mud particles on the surface of the plunger 7. Moreover, turbulence and centrifugal force are generated during the advancement of the swirl. Among them, the turbulence further enhances the ability to peel off the mud particles on the surface of the plunger 7, while the centrifugal force can cause the peeled particles to migrate outward, weakening the risk of particle re-adsorption caused by the reciprocating movement of the plunger 7.

[0035] Through the hydrodynamic design of the spiral diversion groove 21, the kinetic energy of the high-pressure water flow is converted into the dual effects of directional swirl and centrifugal slag discharge, significantly improving the flushing efficiency and particle management ability. Compared with the traditional passive isolation or dispersed circulation solutions, its advantages lie in concentrated pressure, active scouring, and compact structure, especially suitable for extreme working conditions such as shield machines.

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

[0037] Through the design of the gradually expanding flow channel and trapezoidal cross-section of the spiral diversion 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 increasing the cross-sectional area while maintaining the axial propulsion power, reducing energy loss. The upper base of the trapezoidal cross-section is closely attached to the surface of the plunger 7, concentrating the fluid kinetic energy on the area of the plunger 7 to form a strong wall-attached impact shear force to directly peel off the attached substances. Specifically, the high-speed fluid in the upper layer (the upper base of the trapezoidal cross-section) is close to the surface of the plunger 7 to produce a high-gradient shear effect, effectively removing tiny particles; the low-speed fluid in the lower layer (the upper base of the trapezoidal cross-section) expands outward along the trapezoidal slope, and with the help of the centrifugal effect, it pushes large particles to migrate outward. The tangential flow of the spiral propulsion ensures full coverage flushing of the surface of the plunger 7, 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 problems of water flow dispersion and blockage of the traditional structure.

[0038] Furthermore, flow guiding fins 3 are evenly arranged in an array on the bottom of the spiral flow guiding groove 21, and the inner wall of the spiral flow guiding groove 21 and the surface of the flow guiding 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 ≥ HRC65. The combination of the flow guiding fins 3 evenly distributed on the bottom of the spiral flow guiding groove 21 and the tungsten carbide-based wear-resistant coating further optimizes the flow field structure and improves the system durability. Specifically, the flow guiding fins 3 are arranged at equal intervals along a 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 channel into multiple controllable tributaries, forcing the water flow to generate secondary vortices along the inclined surface of the fins, enhancing the penetration of 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, effectively breaking through the cavitation protection layer of the attachment. The tungsten carbide-based wear-resistant coating still maintains structural integrity under long-term high-pressure alternating loads.

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

[0040] In this embodiment, a gasket 4 is embedded at the spiral edge of the spiral flow guiding groove 21 close to the sealing structure 112. The gasket 4 includes a spiral sealing strip 41 arranged along the spiral edge of the spiral flow guiding groove 21 and a transverse sealing strip 42 connected between the two ends of the spiral sealing strip 41. The spiral sealing strip 41 continuously extends along the spiral edge of the flow guiding groove, and its cross-section is in the shape of a dovetail tenon and is embedded in a prefabricated groove. The transverse sealing strip 42 is connected to the two ends of the spiral sealing strip 41 through 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 pulsation conditions.

[0041] In this embodiment, a micro pressure sensor is integrated in the water inlet pipe 22. The pressure sensor is signal-connected to the controller and is used to monitor the inlet pressure of the spiral flow guiding groove 21 in real time and dynamically adjust the water inlet flow rate. When the mud pump performs a pumping operation, the hard particles (such as quartz sand) attached to the surface of the plunger 7 cause an increase in resistance. After the sensor detects a pressure drop, the controller immediately increases the water inlet flow rate to increase the inlet pressure; when the mud pump performs a pumping-in operation, the sensor monitors the pressure fluctuation and maintains the inlet pressure, forming a dynamic isolation barrier to prevent external particles from infiltrating into the sealing area. If an abnormal pressure fluctuation caused by seal wear is detected, the controller fine-tunes the flow rate in real time through the PID algorithm to stabilize the isolation barrier.

[0042] In this embodiment, hemispherical pits (not shown) are provided at the bottom of the spiral flow guiding groove 21. The diameter of the pits is 0.5 - 1 mm, and the depth is 0.2 - 0.5 mm. When the high-pressure cleaning liquid flows through the pits, the hemispherical pits induce local turbulence, break the laminar boundary of the mud layer attached to the surface of the plunger 7, and enhance the stripping ability for micron-sized particles (such as clay and coal powder); the sudden change in geometry at the edge of the pits generates high-gradient shear stress to directly impact hard particles (such as quartz sand), improving the cleaning efficiency. At the same time, the vortices formed in the pits can suspend the stripped particles in the water flow, reducing the risk of secondary attachment. Together with the gradually expanding flow channel of the spiral flow guiding groove 21 and the centrifugal force, the particles are guided to migrate along the trapezoidal inclined plane to the tangent water outlet pipe 23 for rapid discharge.

[0043] The pits are evenly distributed at the bottom of the groove and cooperate with the flow guiding fins 3 to optimize the flow field uniformity, eliminate cleaning dead corners, and their small size avoids sudden pressure drops caused by structural mutations, maintaining the stability of the flow field.

[0044] As Figure 6 shown, in this embodiment, a reverse flushing interface 6 is provided on the water outlet pipe 23. The reverse flushing interface 6 is connected to an external high-pressure water source through a switching valve 61; the switching valve 61 is configured to: connect the water inlet pipe 22 to the spiral flow guiding groove 21 or close the water inlet pipe 22, and connect the reverse flushing interface 6 to the spiral flow guiding groove 21. In the normal cleaning mode, the switching valve 61 opens the passage of the water inlet pipe 22, so that the cleaning water flow flows forward along the spiral direction of the spiral flow guiding groove 21, scouring the mud and guiding it to the water outlet pipe 23; when it is detected that the flow channel is blocked or enhanced cleaning is required, the switching valve 61 immediately closes the passage of the water inlet pipe 22, and at the same time connects the reverse flushing interface 6 to the spiral flow guiding groove 21, and the external high-pressure water is injected reversely into the spiral flow guiding groove 21 from the reverse flushing interface 6, forming an impact force opposite to the normal water flow direction, directly breaking the mud caking deposited between the spiral flow guiding groove 21 and the flow guiding fins 3.

[0045] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution of the present invention and its inventive concept, makes equivalent substitutions or changes, and should be covered by the protection scope of the present invention.

Claims

1. A cleaning mechanism for a slurry pump of a shield machine, which is arranged in a stuffing box (11) of a plunger sleeve (1). A water blocking ring (111) and a sealing structure (112) are arranged in the stuffing box (11), and it is characterized in that, The mud pump cleaning mechanism includes a cleaning ring (2) disposed between a water blocking ring (111) and a sealing structure (112). A spiral diversion groove (21) is formed on the inner side of the cleaning ring (2). The spiral diversion groove (21) is arranged around the outer peripheral surface of the plunger (7) for one week, and an inlet pipe (22) tangent to the spiral diversion groove (21) is connected to the inlet of the spiral diversion groove (21). The inlet pipe (22) penetrates through the stuffing box (11) and the plunger sleeve (1). An outlet pipe (23) tangent to the spiral diversion groove (21) is connected to the outlet of the spiral diversion groove (21). The outlet pipe (23) penetrates through the stuffing box (11) and the plunger sleeve (1).

2. The mud pump cleaning mechanism of the shield machine according to claim 1, characterized in that, The width of the spiral diversion groove (21) gradually increases from the inlet to the outlet, and the cross-section of the spiral diversion groove (21) is trapezoidal. The upper base of the trapezoidal cross-section of the spiral diversion groove (21) faces the plunger (7).

3. The mud pump cleaning mechanism of the shield machine according to claim 1, characterized in that, Flow guiding fins (3) are uniformly arranged in an array on the bottom of the spiral diversion groove (21), and a tungsten carbide-based wear-resistant coating with a coating thickness of 0.1 - 0.3 mm and a hardness ≥ HRC65 covers the inner wall of the spiral diversion groove (21) and the surface of the flow guiding fins (3).

4. The mud pump cleaning mechanism of the shield machine according to claim 3, characterized in that, The height of the flow guiding fins (3) gradually decreases from the inlet to the outlet of the spiral diversion groove (21), and the height difference is 0.5 - 1.2 mm. The leading edge of the flow guiding fins (3) is an acute angle structure, and the acute angle of its leading edge forms an angle of 15° - 20° with the main flow direction. The trailing edge of the flow guiding fins (3) is in arc transition.

5. The mud pump cleaning mechanism of the shield machine according to claim 1, characterized in that, A sealing gasket (4) is embedded at the spiral edge of the spiral diversion groove (21) on the side close to the sealing structure (112). The sealing gasket (4) includes a spiral sealing strip (41) arranged along the spiral edge of the spiral diversion groove (21), and a transverse sealing strip (42) connected between the two ends of the spiral sealing strip (41).

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

7. The mud pump cleaning mechanism of the shield machine according to claim 1, characterized in that Hemispherical pits with a pit diameter of 0.5 - 1 mm and a depth of 0.2 - 0.5 mm are provided on the bottom of the spiral diversion groove (21).

8. The mud pump cleaning mechanism of the shield machine according to claim 1, characterized in that, A reverse flushing interface (6) is provided on the outlet pipe (23). The reverse flushing interface (6) is connected to an external high-pressure water source through a switching valve (61). The switching valve (61) is configured to: connect the inlet pipe (22) to the spiral diversion groove (21) or close the inlet pipe (22), and connect the reverse flushing interface (6) to the spiral diversion groove (21).

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