A piezoelectric-based shield cutter gas explosion cleaning device and a working method thereof

Abstract

The application discloses a piezoelectric type shield cutter disc gas explosion cleaning device, which comprises a plurality of through holes arranged on the shield cutter disc at intervals, a gate valve arranged at the front end of the through hole, and a piezoelectric type gas explosion mechanism arranged at the rear end of the through hole. The piezoelectric type gas explosion mechanism comprises an alternating current transformer, a piezoelectric ceramic, an inflation mechanism and a sealing plate arranged in sequence. The sealing plate and the gate valve jointly enclose the through hole to form a pressurized cylinder. The alternating current transformer is connected with the piezoelectric ceramic and drives the piezoelectric ceramic to produce periodic deformation. The inflation mechanism comprises a shell, the piezoelectric ceramic is packaged on the open end face of the shell, an inflation nozzle and an air suction nozzle are arranged on the other end face of the shell, the inflation nozzle penetrates through the sealing plate and extends into the pressurized cylinder. The piezoelectric type shield cutter disc gas explosion cleaning device has the advantages that the pressurized cylinder is inflated and pressurized through the vibration of the piezoelectric ceramic in the narrow space of the shield cutter disc, high-pressure gas is generated in the pressurized cylinder, when the mud cake is formed on the surface of the shield cutter disc, the gas explosion valve is opened to clean the mud cake through the high-pressure gas.

Description

Technical Field

[0001] This invention belongs to the field of shield tunneling technology, specifically relating to a piezoelectric shield cutterhead air explosion cleaning device and its working method. Background Technology

[0002] The shield tunneling method uses a tunnel boring machine (TBM) for excavation, which requires the TBM to have a certain degree of adaptability to geological formations. In actual engineering practice, when excavating strata such as clay, silty clay, silty clay, and mudstone, clay easily adheres to the surface of the TBM cutterhead. If not cleaned in time, it can easily clog the cutterhead, forming a thick layer of mud cake on the surface. This forces the cutterhead to lose its excavation ability, greatly reduces the penetration depth, and seriously affects the efficiency of the tunneling.

[0003] Therefore, when mud cake forms on the cutterhead of a tunnel boring machine, appropriate methods must be used to remove it.

[0004] For cases where mud cake formation is not severe, the main method is to soak the cutter disc containing the mud cake by injecting liquids such as foaming agents and dispersants. After soaking for a period of time, the cutter disc is rotated at high speed to break up the mud cake through centrifugal force.

[0005] In cases of severe mud cake formation, workers need to enter the tunnel under pressure to clean the mud cake from the cutterhead. Entering the tunnel under pressure requires complex preparations, such as creating a mud film and lowering the mud-water level or the height of the soil chamber. Workers then use hydraulic picks, pneumatic picks, and other tools to break up and remove the mud cake. This process is extremely labor-intensive and risky, with the added risk of tunnel face collapse. In highly unstable geological formations, the tunnel face also needs reinforcement to reduce the risk of opening the tunnel to break up the mud cake. In extremely complex geological formations, it is difficult to open the tunnel under pressure to clean the mud cake, and in some cases, it may be necessary to incur high costs to construct a vertical shaft in front of the tunnel boring machine cutterhead before workers enter to break up the mud cake.

[0006] The soaking method mentioned above is time-consuming, while the manual removal method is obviously inefficient. Therefore, those skilled in the art urgently need a construction device and method that can quickly and efficiently remove mud cakes. Summary of the Invention

[0007] The purpose of this invention is to address the shortcomings of the prior art by providing a piezoelectric shield cutterhead air blast cleaning device and its operating method. This shield cutterhead air blast cleaning device uses piezoelectric ceramics to pressurize the booster cylinder, thereby enabling the arrangement of a high-pressure gas generating device in a confined space to remove mud cake.

[0008] The objective of this invention is achieved through the following technical solutions: A piezoelectric-based pneumatic blasting cleaning device for tunnel cutterheads is characterized in that the device includes several through holes spaced apart on the cutterhead. A gate valve is provided at the front end of each through hole, and a piezoelectric blasting mechanism is provided at the rear end of each through hole. The piezoelectric blasting mechanism includes an AC transformer, a piezoelectric ceramic, an inflation mechanism, and a sealing plate arranged sequentially. The sealing plate is sealed to the inner wall of the through holes, and the sealing plate and the gate valve together enclose the through holes to form a pressurizing cylinder. The piezoelectric ceramic is fixed to the outer surface of the sealing plate. The AC transformer is connected to the piezoelectric ceramic and drives it to undergo periodic deformation. The inflation mechanism includes a housing, with the piezoelectric ceramic encapsulated on the open end face of the housing. An inflation nozzle and an intake nozzle are provided on the other end face of the housing. The inflation nozzle penetrates the sealing plate and extends into the pressurizing cylinder, while the intake nozzle is connected to the atmosphere.

[0009] The gate valve consists of a solenoid valve and a gas explosion valve. The gas explosion valve opens after the gas in the pressurization cylinder reaches a set pressure value.

[0010] The gas explosion valve includes a cylinder, a compression spring, and a piston rod. The outer wall of the cylinder is sealed to the inner wall of the pressurizing cylinder. The compression spring is disposed between the piston rod and the front end face of the cylinder. One end of the piston rod is a disc and is slidably connected to the inner wall of the cylinder. An explosion channel is opened in the middle wall of the cylinder. The other end of the piston rod is a top plate and passes through the front end face of the cylinder when it is pushed out.

[0011] The housing contains two pipes. One pipe is connected to the air intake nozzle, which is equipped with a one-way valve to allow the piezoelectric ceramic to draw in air. The other pipe is connected to the air filling nozzle, which is equipped with a one-way valve to allow the piezoelectric ceramic to pressurize the pressurized cylinder through the air filling nozzle.

[0012] A method for operating the aforementioned piezoelectric-based shield cutterhead gas explosion cleaning device is characterized by the following steps: closing all electromagnetic valves and gas explosion valves within each pressurization cylinder on the shield cutterhead; applying alternating voltage to the piezoelectric ceramic via an AC transformer to induce periodic deformation vibration in the piezoelectric ceramic, which then draws in air through an intake nozzle and pressurizes the pressurization cylinder through an inflation nozzle, repeating this process until a set pressure or a set operating time is reached, at which point the process stops; when a gas explosion cleaning device is detected on the shield cutterhead... When there is mud cake, the surface of the shield cutterhead is spaced at a set distance from the excavation face. Then, the electromagnetic valve is opened, causing the compressed gas in the pressurization cylinder to drive the gas explosion valve to open. This drives the disc on the piston rod of the gas explosion valve to compress the spring inward. The top plate on the piston rod pushes the mud cake forward, and the compressed gas flows out through the gas explosion channel opened on the cylinder. The compressed gas impacts the mud cake outward, causing it to fall off the surface of the shield cutterhead. Finally, the shield cutterhead is rotated at high speed, and the remaining broken mud cake is thrown away by centrifugal force.

[0013] The advantages of this invention are: within the narrow space of the shield cutterhead, the piezoelectric ceramic vibrates to pressurize the booster cylinder, generating high-pressure gas inside. When mud cake forms on the surface of the shield cutterhead, the gas explosion valve is opened to clean the mud cake with high-pressure gas. The ejected piston rod also pushes the mud cake outward, achieving a dual cleaning of the mud cake. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the shield cutterhead cleaning device in this invention when the gas explosion valve is not opened; Figure 2 This is a schematic diagram of the shield cutterhead cleaning device opening the gas explosion valve in this invention. Detailed Implementation

[0015] The features and other related features of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments, so as to facilitate understanding by those skilled in the art: like Figure 1-2 The markings in the figure are as follows: 1. Shield cutterhead, 2. Through hole, 3. Pressurization cylinder, 4. Sealing plate, 5. Shell, 6. Air inlet, 7. Piezoelectric ceramic, 8. AC power transformer, 9. Solenoid valve, 10. Aeration channel, 11. Air explosion valve, 12. Cylinder, 13. Disc, 14. Piston rod, 15. Compression spring, 16. Top plate, 17. Mud cake.

[0016] Example: Figure 1 , 2As shown, this embodiment specifically relates to a piezoelectric shield cutterhead air blast cleaning device and its working method. The shield cutterhead air blast cleaning device includes a plurality of through holes 2 spaced apart on the shield cutterhead 1. Each through hole 2 contains a pressurized cylinder 3 capable of generating an air blast effect. When opening the through holes 2, the locations on the surface of the shield cutterhead 1 where mud cake is easily formed are selected for arrangement. Based on daily construction experience, it has been found that mud cake is prone to appear at uneven locations such as the cutter head. By controlling the frequency of air blast cleaning, mud cake can be removed in time to prevent hardening.

[0017] like Figure 1 , 2 As shown, a gate valve mechanism is installed at the front end of the through hole 2, and a piezoelectric gas explosion mechanism is installed at the rear end of the through hole. The piezoelectric gas explosion mechanism includes an AC transformer 9, a piezoelectric ceramic 8, an inflation mechanism, and a sealing plate 4 arranged sequentially. The sealing plate 4 is circular, and its outer edge is sealed to the inner wall of the through hole 2. The sealing plate 4 and the gate valve mechanism together enclose the through hole 2 to form a pressurizing cylinder 3, achieving gas compression and pressurization within it. The inflation mechanism includes a housing 5, inside which are two pipes. One pipe connects to an inflation nozzle 6, and the other connects to an intake nozzle 7. The piezoelectric ceramic 8 is located on the port face of the housing 5, and to ensure sealing, a cavity is encapsulated on the outside of the piezoelectric ceramic 8. The piezoelectric ceramic 8 is connected to the AC transformer 9. The piezoelectric ceramic 8 is typically cylindrical or disc-shaped and is installed inside the cavity. When an alternating voltage is applied, the piezoelectric ceramic 8 undergoes periodic deformation, causing periodic compression and expansion of the gas inside the cavity. Specifically, when the piezoelectric ceramic 8 deforms, it draws in air through the suction nozzle 7, which is connected to the atmosphere. The suction nozzle 7 is equipped with a one-way valve that only allows air to be drawn in and not expelled. The drawn-in air is then pumped into the pressurizing cylinder 3 through the inflation nozzle 6, which also contains a one-way valve that only allows air to be pumped into the pressurizing cylinder 3 and does not allow air to be expelled in the reverse direction. Through the continuous deformation and vibration of the piezoelectric ceramic 8, continuous inflation into the pressurizing cylinder 3 can be achieved.

[0018] like Figure 1 , 2As shown, the gate valve mechanism includes a solenoid valve 10 and a pneumatic explosion valve 12, which are arranged sequentially from the inside out to form two valves. A pressure sensor is installed inside the pressurization cylinder 3 to monitor the pressure value inside the pressurization cylinder 3. The solenoid valve 10 selects whether to open based on a control signal. The gas explosion valve 12 includes a cylinder 13, a compression spring 16, and a piston rod 15. The cylinder 13 is tightly fitted to the solenoid valve 10. The piston rod 15 is installed inside the cylinder 13. The disc 14 at the end of the piston rod 15 is tightly fitted to the pipe opening of the solenoid valve 10, and the disc 14 is slidably assembled with the inner wall of the cylinder 13. The compression spring 16 is fitted onto the piston rod 15 and provides an inward compression force to the disc 14. The other end of the compression spring 16 is fixed to the end face of the cylinder 13, thereby providing a reaction force to support its compression force. A hole is opened on the end face of the cylinder 13 so that the other end of the piston rod 15 can pass through the hole. A top plate 17 is fixedly installed on the end of the piston rod 15 that passes through and protrudes. The top plate 17 is hemispherical and can break the mud cake 18 when it is pushed out. A ring of venting channels 11 is formed on the side wall of the lower part of the cylinder 13, outside the initial position of the disc 14. The channels of the venting channels 11 are connected to the surface of the shield cutterhead 1. When the solenoid valve 10 is opened and the pressure of the compressed gas in the pressurized cylinder 3 is greater than the clamping force of the compression spring 16 on the disc 14, the compressed high-pressure gas pushes the disc 14 and the piston rod 15 outward. At this time, the high-pressure gas will be quickly discharged outward from the venting channels 11 on the side wall of the cylinder 3. The high-pressure gas generates an venting phenomenon from the venting channels 11, which impacts the mud cake off the surface of the shield cutterhead 1 or breaks it off. The top plate 17, which is subjected to the pushing force, also moves outward with the piston rod 15 and pushes the mud cake 17 off.

[0019] like Figure 1 , 2 As shown, the working method of the shield cutterhead gas explosion cleaning device in this embodiment includes the following steps: (S1) In the initial state or under the inflation state, close the solenoid valve 10 and the gas explosion valve 12 in each pressure cylinder 3 on the shield cutterhead 1 so that only gas can be filled into the pressure cylinder 3 for pressurization.

[0020] (S2) An alternating voltage is applied to the piezoelectric ceramic 8 via the AC transformer 9, causing the piezoelectric ceramic 8 to undergo periodic deformation vibration. The piezoelectric ceramic 8 draws in air through the suction nozzle 7 and fills the pressure boosting cylinder 3 through the inflation nozzle 6. This process is repeated until the set pressure or set working time is reached, at which point it stops. Of course, other types of air pumps can also be considered, but their size may be too large, requiring corresponding optimization. Generally, in order to achieve an instantaneous high-pressure impact, the pressure inside the pressure boosting cylinder 3 should be at least 2-3 times the clamping force of the compression spring 16. Therefore, the purpose of setting two valves in the gate valve mechanism is to accumulate pressure and prevent leakage, with the solenoid valve 10 playing a crucial role in accumulating high-pressure gas.

[0021] (S3) When mud cake is detected on the shield cutterhead 1, the surface of the shield cutterhead 1 is separated from the excavation face by a set distance. The monitoring method can generally be video monitoring or abnormal torque during shield rotation, which can determine that mud cake may be generated; of course, an appropriate frequency can also be set for automatic cleaning. Open the solenoid valve 10 to drive the gas explosion valve 12 in the pressurization cylinder 3 to open, that is, drive the disc 14 on the piston rod 15 in the gas explosion valve 12 to compress the clamping spring 16 inward, and push the mud cake forward on the top plate 17 on the piston rod 15. The compressed gas flows outward through the explosion channel 11 opened on the cylinder 13 and rushes outward from the surface of the shield cutterhead 1. The compressed gas impacts the mud cake 18 outward, causing the mud cake 18 to fall off the surface of the shield cutterhead 1. Finally, the shield cutterhead 1 is rotated at high speed, and the remaining broken mud cake 18 is thrown away by centrifugal force.

[0022] The advantages of this embodiment are: within the narrow space of the shield cutterhead, the piezoelectric ceramic vibration inflates the pressurizing cylinder, generating high-pressure gas inside. When mud cake forms on the surface of the shield cutterhead, the gas explosion valve is opened to clean the mud cake with high-pressure gas, and the ejected piston rod also pushes the mud cake outward, achieving dual cleaning of the mud cake; and compared to traditional air pumps, the air inflation mechanism of each piezoelectric ceramic can work independently, and occupies less space, allowing it to be directly installed on the surface of the shield cutterhead, forming a high-density installation.

Claims

1. A working method for a piezoelectric shield cutterhead gas explosion cleaning device, characterized in that... The shield cutterhead gas explosion cleaning device includes several through holes spaced apart on the shield cutterhead. A gate valve is provided at the front end of each through hole, and a piezoelectric gas explosion mechanism is provided at the rear end of each through hole. The piezoelectric gas explosion mechanism includes an AC transformer, a piezoelectric ceramic, an inflation mechanism, and a sealing plate arranged in sequence. The sealing plate is sealed to the inner wall of the through hole. The sealing plate and the gate valve together enclose the through hole to form a pressurization cylinder. The piezoelectric ceramic is fixed to the outer surface of the sealing plate. The AC transformer is connected to the piezoelectric ceramic and drives the piezoelectric ceramic to produce periodic deformation. The inflation mechanism includes a shell. The piezoelectric ceramic is encapsulated on the open end face of the shell. An inflation nozzle and an air intake nozzle are provided on the other end face of the shell. The inflation nozzle passes through the sealing plate and extends into the pressurization cylinder. The air intake nozzle is connected to the atmosphere. The gate valve consists of an electromagnetic valve and a gas explosion valve. The gas explosion valve opens after the gas in the pressurization cylinder reaches a set pressure value. The gas explosion valve includes a cylinder, a compression spring, and a piston rod. The outer wall of the cylinder is sealed to the inner wall of the pressurization cylinder. The compression spring is disposed between the piston rod and the front end face of the cylinder. One end of the piston rod is a disc and is slidably connected to the inner wall of the cylinder. An explosion channel is opened in the middle wall of the cylinder. The other end of the piston rod is a top plate and passes through the front end face of the cylinder when it is pushed out. The operating method of the shield cutterhead air explosion cleaning device includes the following steps: closing each of the solenoid valves and air explosion valves in each of the pressurization cylinders on the shield cutterhead; applying alternating voltage to the piezoelectric ceramic through the AC transformer to cause the piezoelectric ceramic to generate periodic deformation vibration, the piezoelectric ceramic drawing in air through the suction nozzle and inflating the pressurization cylinder through the inflation nozzle, repeating this process until a set pressure or a set working time is reached and then stopping; when mud cake is detected on the shield cutterhead, the shield... The cutterhead surface is spaced a set distance from the excavation face. Then, the electromagnetic valve is opened, causing the compressed gas in the pressurization cylinder to drive the gas explosion valve to open. This drives the disc on the piston rod of the gas explosion valve to compress the clamping spring inward. The top plate on the piston rod pushes the mud cake forward, and the compressed gas flows out through the gas explosion channel opened on the cylinder. The compressed gas impacts the mud cake outward, causing it to fall off the surface of the shield cutterhead. Finally, the shield cutterhead is rotated at high speed, and the remaining broken mud cake is thrown away by centrifugal force.

2. The working method of the piezoelectric shield cutterhead gas explosion cleaning device according to claim 1, characterized in that... The housing contains two pipes. One pipe is connected to the air intake nozzle, which is equipped with a one-way valve to allow the piezoelectric ceramic to draw in air. The other pipe is connected to the air filling nozzle, which is equipped with a one-way valve to allow the piezoelectric ceramic to pressurize the pressurized cylinder through the air filling nozzle.

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