Piezoelectric-based shield cutter high-pressure mud cake cleaning device and working method

Abstract

The application discloses a piezoelectric high-pressure detonation mud cake cleaning device for a shield cutter, which comprises a plurality of through holes formed on the shield cutter, and gate valves and piezoelectric gas explosion mechanisms arranged at the front end and the rear end of the through holes respectively; the piezoelectric gas explosion mechanism comprises an alternating current transformer, a piezoelectric ceramic, an inflation mechanism and a sealing plate; the gate valve comprises an electromagnetic valve and a gas explosion valve; the gas explosion valve comprises a cylinder, a compression spring and a piston rod, the front end surface of the cylinder is provided with a sealing end plate and is provided with a through hole in the center, one end of the piston rod penetrates through the through hole and is fixedly provided with a top plate, the other end of the piston rod is fixedly provided with a disc and is slidably connected with the inner wall surface of the cylinder, and a gas explosion channel is formed in the wall surface of the cylinder; a plurality of booster channels are formed in the outer surface of the top plate, and a flexible sealing bag is sealed on the outer surface of the top plate. The piezoelectric high-pressure detonation mud cake cleaning device has the advantages that it is suitable for the narrow space of the shield cutter, and the piston rod and the flexible sealing bag on the top plate realize the secondary cleaning of the mud cake.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of shield construction, and particularly relates to a piezoelectric-based shield cutterhead high-pressure mud cake cleaning device and working method. BACKGROUND

[0002] The shield method adopts a shield machine for excavation and tunneling, which requires the shield machine to have certain adaptability to the stratum. In engineering practice, when the shield machine excavates clay, silt clay, silty clay, mudstone and the like, the shield cutterhead surface is prone to adhere to clay, and if not cleaned in time, the cutterhead is easily covered with mud cake, which forces the cutterhead to lose the excavation capability and greatly reduces the penetration, thereby seriously affecting the shield tunneling efficiency.

[0003] Therefore, for the case of mud cake on the shield cutterhead, appropriate means need to be used for cleaning.

[0004] For the case of not serious mud cake, mainly liquid such as foam agent and dispersant is injected to soak the cutterhead with mud cake, and the cutterhead is rotated at high speed after soaking for a period of time, so that the mud cake is thrown away by centrifugal force.

[0005] For the case of serious mud cake, workers need to enter the chamber under pressure to clean the mud cake on the cutterhead. The workers enter the chamber under pressure need complex preparation work, such as making mud film, reducing the mud water chamber liquid level or reducing the height of the soil chamber. The workers enter the chamber under pressure use hydraulic pick, air pick and the like to break and clean the mud cake, and the workers have great labor intensity and high risk, and face the risk of collapse of the working face; for extremely unstable stratum, the working face needs to be reinforced to reduce the risk of breaking the mud cake when opening the chamber. For extremely complex stratum, it is difficult to open the chamber to clean the mud cake under pressure, and even a high cost is spent on constructing a vertical shaft in front of the shield cutterhead, and then the workers enter the front of the cutterhead to break the mud cake.

[0006] The soaking method has the problem of long time consumption, and the manual cleaning method has the problem of low efficiency, so the technical personnel in the field urgently need a construction device and method capable of quickly and efficiently cleaning mud cake. SUMMARY

[0007] The purpose of the present application is to provide a piezoelectric-based shield cutterhead high-pressure mud cake cleaning device and working method according to the deficiencies of the prior art, which realizes the first-stage explosion cleaning of the mud cake through the top plate, and realizes the second-stage explosion cleaning through the flexible sealing bag on the top plate.

[0008] The purpose of the present application is achieved by the following technical scheme:

[0009] The invention discloses a piezoelectric high-pressure explosion mud cake cleaning device for a shield cutter, which is characterized in that the mud cake cleaning device comprises a plurality of through holes arranged on the shield cutter, a gate valve arranged at the front end of the through hole, and a piezoelectric gas explosion mechanism arranged at the rear end of the through hole.

[0010] The top plate is in the form of a boss, and the front end of the cylinder is provided with a limiting plate to limit the outward stroke of the top plate; the entrance of the gas explosion channel is arranged in front of the disc and communicates with the inner cavity of the cylinder, and is located in front of the gas explosion channel when the disc is pushed outwards; the outlet of the gas explosion channel is arranged on the front end surface of the cylinder, and the outlet of the gas explosion channel communicates with the pressurization channel arranged on the top plate when the top plate is pushed outwards.

[0011] The piezoelectric ceramic is fixed on the outer surface of the sealing plate, the alternating current power supply device is connected to the piezoelectric ceramic and drives the piezoelectric ceramic to produce periodic deformation, the air charging mechanism comprises a shell, the piezoelectric ceramic is packaged on the open end surface of the shell, an air charging nozzle and an air suction nozzle are arranged on the other end surface of the shell, the air charging nozzle penetrates the sealing plate and extends into the pressurizing cylinder, and the air suction nozzle communicates with the atmosphere.

[0012] Two pipelines are distributed in the shell, one of which is connected to the air suction nozzle, a one-way valve is arranged in the air suction nozzle to enable the piezoelectric ceramic to inhale through the air suction nozzle, and the other pipeline is connected to the air charging nozzle, a one-way valve is arranged in the air charging nozzle to enable the piezoelectric ceramic to pressurize the pressurizing cylinder through the air charging nozzle.

[0013] The application discloses a working method of the piezoelectric-based shield cutter high-pressure mud cake cleaning device, and is characterized by the following steps: closing the electromagnetic valve and the gas explosion valve in each pressure cylinder on the shield cutter; applying alternating voltage to the piezoelectric ceramic through an alternating current transformer to make the piezoelectric ceramic generate periodic deformation vibration, the piezoelectric ceramic inhales air through an air suction nozzle and inhales air into the pressure cylinder through an air charging nozzle, and the process is repeated until the set pressure or the set working time is reached; when it is monitored that the shield cutter is covered with mud cake, the surface of the shield cutter is separated from the excavation surface by a set distance, then the electromagnetic valve is opened, the compressed gas in the pressure cylinder drives the gas explosion valve to open, namely, the disc on the piston rod in the gas explosion valve compresses the compression spring inward, the top plate on the piston rod pushes the mud cake forward, and the first-stage explosion of the mud cake is realized; when the disc is pushed outward, the compressed gas enters the explosion gas channel from the inlet of the explosion gas channel and flows out from the outlet of the explosion gas channel into the pressure hole in the top plate, so that the flexible sealing bag on the outer surface of the top plate is filled with air, and the second-stage explosion of the mud cake is realized; finally, the shield cutter is rotated at high speed, and the remaining broken mud cake is thrown away by centrifugal force.

[0014] The application has the following advantages:

[0015] (1) The application is suitable for the narrow space of the shield cutter.

[0016] (2) The piezoelectric ceramic is vibrated to charge and pressurize the pressure cylinder, high-pressure gas is generated in the pressure cylinder, when the shield cutter is covered with mud cake, the gas explosion valve is opened, the top plate on the piston rod is pushed out to realize the first-stage explosion of the mud cake, the compressed gas enters the explosion gas channel from the inlet of the explosion gas channel and flows out from the outlet of the explosion gas channel into the pressure hole in the top plate, so that the flexible sealing bag on the outer surface of the top plate is filled with air, the second-stage explosion of the mud cake is realized, and the two-stage cleaning of the mud cake is realized. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 FIG. 1 is a schematic view of the shield cutter cleaning device without the gas explosion valve being opened in the application;

[0018] Figure 2 FIG. 2 is a schematic view of the shield cutter cleaning device with the gas explosion valve being opened in the application. DETAILED DESCRIPTION

[0019] The features and other related features of the application are further described in detail below with reference to the accompanying drawings, so as to be understood by the technicians in the same industry:

[0020] As Figures 1-2, the various marks in the figure are respectively: shield cutter 1, through hole 2, booster cylinder 3, sealing plate 4, shell 5, air inlet nozzle 6, air inlet nozzle 7, piezoelectric ceramic 8, alternating current transformer 9, electromagnetic valve 10, gas explosion hole 11, gas explosion valve 12, cylinder 13, disc 14, piston rod 15, compression spring 16, top plate 17, booster hole 18, limit plate 19, mud cake 20, flexible sealing bag 21.

[0021] Embodiment: as shown in Figure 1 , 2 , the embodiment specifically relates to a piezoelectric-based shield cutter high-pressure gas explosion mud cake cleaning device and a working method thereof. The shield cutter gas explosion cleaning device comprises a plurality of through holes 2 arranged on the shield cutter 1 at intervals, each through hole 2 is provided with a booster cylinder 3 capable of generating a gas explosion effect. When the through hole 2 is arranged, the position prone to mud cake formation on the surface of the shield cutter 1 is selected for arrangement. Based on the daily construction situation, it is found that the position prone to mud cake formation is prone to appear at the concave-convex position of the cutter. By controlling the frequency of gas explosion cleaning, the mud cake can be removed in time to avoid hardening.

[0022] As shown in Figure 1 , 2 , the front end of the through hole 2 is provided with a gate valve mechanism, and the rear end of the through hole is provided with a piezoelectric gas explosion mechanism. The piezoelectric gas explosion mechanism comprises alternating current transformer 9, piezoelectric ceramic 8, air charging mechanism and sealing plate 4 arranged in sequence. The sealing plate 4 is circular and its outer edge is sealingly connected and packaged with the inner wall of the through hole 2. The sealing plate 4 and the gate valve mechanism jointly enclose the through hole 2 to form a booster cylinder 3, so as to realize the compression and boosting of the gas in the booster cylinder 3. The air charging mechanism comprises a shell 5, two pipelines are distributed in the shell 5, one pipeline is connected with the air inlet nozzle 6, and the other pipeline is connected with the air inlet nozzle 7. The piezoelectric ceramic 8 is arranged on the port surface of the shell 5, and a cavity is encapsulated on the outside of the piezoelectric ceramic 8 to ensure the sealing. The piezoelectric ceramic 8 is connected with the alternating current transformer 9, and is usually in the shape of a cylinder or a disc and is installed in the cavity. When an alternating voltage is applied, the piezoelectric ceramic 8 will produce periodic deformation, thereby causing the periodic compression and expansion of the gas in the cavity. Specifically, when the piezoelectric ceramic 8 deforms, it will inhale air from the air inlet nozzle 7, and the air inlet nozzle 7 is connected with the atmosphere. A one-way valve is arranged in the air inlet nozzle 7, which only allows air to be inhaled inward and cannot be exhausted outward. The inhaled gas is charged into the booster cylinder 3 through the air inlet nozzle 6, and a one-way valve is also arranged in the air inlet nozzle 6, which only allows the air to be charged into the booster cylinder 3 and cannot be exhausted in the opposite direction. Through the continuous deformation and vibration of the piezoelectric ceramic 8, continuous air charging into the booster cylinder 3 can be realized.

[0023] As shown in Figure 1 , 2As shown, the gate valve mechanism includes electromagnetic valve 10 and gas explosion valve 12, which are arranged in sequence from inside to outside, forming two valves. The pressure sensor (not shown in the figure) is arranged in the pressurizing cylinder 3 to monitor the pressure value in the pressurizing cylinder 3. The electromagnetic valve 10 is selected to be opened or not based on the control signal. The gas explosion valve 12 includes a cylinder 13, a compression spring 16, and a piston rod 15, the cylinder 13 is arranged closely with the electromagnetic valve 10, the piston rod 15 is installed in the cylinder 13, the disc 14 at the end of the piston rod 15 is arranged closely at the pipeline port of the electromagnetic valve 10, and the disc 14 is slidably assembled with the inner wall surface of the cylinder 13, the compression spring 16 is sleeved on the piston rod 15 and provides an inward compression force to the disc 14, the other end of the compression spring 16 is fixed on the encapsulating end plate of the cylinder 13, thereby providing a counterforce support for the compression force; a hole is formed in the encapsulating end plate of the cylinder 13 to allow the other end of the piston rod 15 to penetrate the hole, and the protruding end of the piston rod 15 is fixedly provided with a top plate 17, the top plate 17 is in the form of a boss, and a limiting plate 19 is arranged at the front end of the cylinder 13 to limit the first level of the top plate 17. A flexible sealing bag 21 is encapsulated on the outer surface of the top plate 17, and a plurality of pressurizing channels 18 are spaced apart on the top plate 17, and the flexible sealing bag 21 can be inflated to push the mud cake 20 by inflating the flexible sealing bag 21 through the pressurizing channels 18. The cylinder 13 has a relatively thick wall, and the gas explosion channel 11 is formed in the wall, the inlet of the gas explosion channel 11 is connected to the inside of the cylinder 13, and the inlet of the gas explosion channel 11 is formed at the middle and lower part of the cylinder, specifically at the upper part when the disc 14 is at the initial state position, so that when the disc 14 is tightly attached to the electromagnetic valve 10, the gas explosion channel 11 is isolated from the pressurizing cylinder 3, and when the disc 14 is pushed outward, the gas explosion channel 11 can suck in the compressed gas in the pressurizing cylinder 3. The outlet of the gas explosion channel 11 is formed on the front end surface of the cylinder 3 and is blocked by the top plate 17 in the initial state, and when the top plate 17 is pushed outward, the space left makes the outlet of the gas explosion channel 11 form a communication with the pressurizing channel 18, so that the compressed gas can be filled into the flexible sealing bag 21 through the gas explosion channel 11 and the pressurizing channel 18, and the flexible sealing bag 21 inflated by the filling of the compressed gas can form a second level of impact explosion on the mud cake 20.

[0024] As shown in Figure 1 , 2 The working method of the shield cutterhead high-pressure explosion mud cake cleaning device based on piezoelectricity in the embodiment includes the following steps:

[0025] (S1) In the initial state or below the inflation state, the electromagnetic valve 10 and the gas explosion valve 12 in each pressurizing cylinder 3 on the shield cutterhead 1 are closed, so that only gas can be filled in the pressurizing cylinder 3 for pressurization.

[0026] (S2) By alternating current power supply device 9 to piezoelectric ceramic 8, piezoelectric ceramic 8 produces periodic deformation vibration, piezoelectric ceramic 8 through the suction nozzle 7 suction and through the inflation nozzle 6 to the pressure cylinder 3 inside the inflation, so reciprocating, until the set pressure or set working time after stopping; of course, other types of air pump can also be considered, but the volume is too large, the need for appropriate optimization. Generally, in order to be able to achieve instantaneous high pressure impact, the pressure in the pressure cylinder 3 is filled to at least 2-3 times the pressure of the compression spring 16 is appropriate. Therefore, the gate valve mechanism is provided with two valves to accumulate pressure without leakage, solenoid valve 10 plays a significant role in the accumulation of high pressure gas.

[0027] (S3) When monitoring the shield cutter 1 on the mud cake, the surface of the shield cutter 1 is spaced apart from the excavation surface by a set distance, the monitoring means can be video monitoring or torque anomaly when the shield rotates, it can be judged that the mud cake may be generated; of course, the appropriate frequency can also be set to automatically clean regularly. Open solenoid valve 10, the compressed gas in the pressure cylinder 3 drives the gas explosion valve 12 to open, that is, the disc 14 on the piston rod 15 compresses the compression spring 16 to compress inward, under the drive of the piston rod 15, the top plate 17 moves outward quickly and produces the first level of explosion thrust on the mud cake 20; with the disc 14 sliding outward in the cylinder 13, the inlet of the explosion gas channel 11 is connected with the pressure cylinder 3, and with the top plate 17 outward thrust, the outlet of the explosion gas channel 11 also forms communication with the pressure channel 18 on the top plate 17, the high pressure compressed gas fills into the flexible sealing bag 21 through the explosion gas channel 11 and the pressure channel 18, so that the volume of the flexible sealing bag 21 expands rapidly, thereby forming the second level of explosion thrust on the mud cake 20, so that the mud cake 20 falls off from the surface of the shield cutter 1.

[0028] (S4) Finally, the shield cutter 1 is rotated at high speed, and the remaining broken mud cake 20 is thrown away by centrifugal force.

[0029] The beneficial effects of the embodiment are:

[0030] (1) suitable for the narrow space of the shield cutter;

[0031] (2) the piezoelectric ceramic is vibrated to inflate the pressure cylinder, so that high pressure gas is generated in the pressure cylinder, when the mud cake is formed on the surface of the shield cutter, the gas explosion valve is opened, the top plate on the piston rod is exploded and thrust to the first level, the compressed gas enters from the inlet of the explosion gas channel and flows out from the outlet of the explosion gas channel to the pressure channel on the top plate, so that the flexible sealing bag on the outer surface of the top plate is filled with gas, the second level of explosion thrust is realized, and the second level of cleaning of the mud cake is realized.

Claims

1. A piezoelectric-based shield cutter high-pressure explosion mud cake cleaning device, characterized in that The mud cake cleaning device comprises a plurality of through holes arranged on a shield cutter in a spaced manner, a gate valve arranged at a front end of the through hole, and a piezoelectric gas explosion mechanism arranged at a rear end of the through hole; the piezoelectric gas explosion mechanism comprises an alternating current transformer, a piezoelectric ceramic, an inflation mechanism and a sealing plate arranged in sequence, the sealing plate is sealed and packaged with an inner wall surface of the through hole, and the sealing plate and the gate valve jointly enclose the through hole to form a pressurized cylinder; the gate valve comprises an electromagnetic valve and a gas explosion valve arranged in the pressurized cylinder in a sequence from inside to outside; the gas explosion valve comprises a cylinder, a compression spring and a piston rod, an outer wall surface of the cylinder is sealingly connected with an inner wall surface of the pressurized cylinder, a front end surface of the cylinder is provided with a packaging end plate and a through hole is arranged at the center, one end of the piston rod penetrates through the through hole and is fixedly provided with a top plate, the other end of the piston rod is fixedly provided with a disc and is slidingly connected with an inner wall surface of the cylinder, and a gas explosion channel is arranged in a wall surface of the cylinder; a plurality of pressurizing channels are arranged on an outer surface of the top plate and a flexible sealing bag is packaged on the outer surface.

2. The piezoelectric-based shield cutter high-pressure explosion mud cake cleaning device according to claim 1, characterized in that The top plate is in a boss type, a limiting plate is arranged at a front end of the cylinder to limit an outward elastic stroke of the top plate; an inlet of the gas explosion channel is arranged in front of the disc and is connected with an inner cavity of the cylinder and is located in front of the gas explosion channel when the disc is pushed outwards; an outlet of the gas explosion channel is arranged at the front end surface of the cylinder and is connected with the pressurizing channel arranged on the top plate when the top plate is pushed outwards.

3. The piezoelectric-based shield cutter high-pressure explosion mud cake cleaning device according to claim 1, characterized in that The piezoelectric ceramic is fixed on an outer surface of the sealing plate, the alternating current transformer is connected with the piezoelectric ceramic and drives the piezoelectric ceramic to generate periodic deformation, the inflation mechanism comprises a shell, the piezoelectric ceramic is packaged on an open end surface of the shell, an inflation nozzle and an air suction nozzle are arranged on the other end surface of the shell, the inflation nozzle penetrates through the sealing plate and extends into the pressurized cylinder, and the air suction nozzle is connected with the atmosphere.

4. The piezoelectric-based shield cutter high-pressure explosion mud cake cleaning device according to claim 3, characterized in that Two pipelines are arranged in the shell, one of the pipelines is connected with the air suction nozzle, a one-way valve is arranged in the air suction nozzle to enable the piezoelectric ceramic to inhale through the air suction nozzle, and the other pipeline is connected with the inflation nozzle, a one-way valve is arranged in the inflation nozzle to enable the piezoelectric ceramic to pressurize the pressurized cylinder through the inflation nozzle.

5. A method for working the piezoelectric-based high-pressure mud cake cleaning device for a shield cutterhead according to any one of claims 1 to 4, characterized in that The working method comprises the following steps: closing each electromagnetic valve and gas explosion valve in each pressure cylinder on a shield cutter head; applying alternating voltage to a piezoelectric ceramic through an alternating current transformer to make the piezoelectric ceramic generate periodic deformation vibration, the piezoelectric ceramic inhales air through an air suction nozzle and charges air into the pressure cylinder through an air charging nozzle, and the process is repeated until a set pressure or a set working time is reached and then stopped; when it is monitored that the shield cutter head is covered with a mud cake, the surface of the shield cutter head is spaced apart from an excavation surface by a set distance, then the electromagnetic valve is opened, compressed gas in the pressure cylinder drives the gas explosion valve to open, i.e. a disc on a piston rod of the gas explosion valve compresses and tightens a spring inward, a top plate on the piston rod pushes the mud cake forward to realize first-stage explosion of the mud cake; when the disc is pushed outward, compressed gas enters from an inlet of a gas explosion channel and flows out from an outlet of the gas explosion channel into a pressure channel on the top plate to fill a flexible sealing bag on the outer surface of the top plate with gas, thereby realizing second-stage explosion of the mud cake; and finally, the shield cutter head is rotated at high speed to throw away the remaining broken mud cake through centrifugal force.

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