Pressure maintaining system for air cushion bin of shield tunneling machine

Abstract

The invention relates to the technical field of shield tunneling machine air cushion bin pressure maintaining, in particular to a pressure maintaining system for a shield tunneling machine air cushion bin, which comprises a main system, a standby system, a shared pressure difference adjusting device, a pressure relieving device, a control module and a pressure detection device. The main system and the standby system are each provided with a gas processing device, a gas inlet control valve, a signal intensifier, an exhaust control valve and a noise suppression device. Pressure balance of main and standby systems is achieved through the pressure difference adjusting device, impurities are filtered through the gas processing device, pressure is dynamically adjusted through the pressure relieving device, the response speed is increased through the signal intensifier, and exhaust noise is eliminated through the noise suppression device. The control precision, the response speed and the adaptability of the pressure maintaining system can be improved, the problem of inconvenient operation under complex working conditions is solved, and an efficient intelligent solution is provided for tunnel construction.

Description

Technical Field

[0001] The present invention belongs to the technical field of shield machine construction, and specifically relates to a pressure maintaining system for the air cushion chamber of a shield machine. Background Technique

[0002] During the tunnel construction process, the pressure maintaining system of the air cushion chamber of a shield machine is one of the key technologies to ensure the stability of the excavation face and construction safety. At present, the research on the pressure maintaining system of the air cushion chamber of shield machines at home and abroad mainly focuses on maintaining the stability of the face pressure through compressed air automatic regulation technology. However, the existing pressure maintaining systems still have many deficiencies under complex working conditions, such as insufficient control accuracy, slow response speed, and inconvenient operation. These problems may affect the construction efficiency and pose certain safety hazards.

[0003] The patent with the publication number CN11478214126B proposes a pressure maintaining control system for the circulating air cushion chamber of a shield machine. By setting multiple electro-hydraulic proportional control valves and pressure detectors, it realizes the functions of rapid inflation and pressurization or exhaust and pressure relief according to real-time pressure changes, and achieves precise flow control when approaching the target pressure. However, the components of this technical solution are relatively complex, and it relies on high-precision pressure detectors and controllers, which increases the cost of the system to a certain extent and may bring certain inconveniences to on-site construction operations. In addition, the control logic of this system depends on the coordinated work of multiple electro-hydraulic proportional control valves, and there may be certain delays and errors in actual applications, thus affecting the control accuracy and response speed.

[0004] Meanwhile, the patent with the publication number CN10601141466B proposes a water pressure and air pressure balance control system for a shield machine in a water-rich stratum. By setting multiple sensors in the soil chamber of the shield machine and combining an industrial control computer and an air compressor, it realizes the dynamic balance control of the pressure in the soil chamber of the shield machine. However, the control strategy of this technical solution is mainly designed for the special working conditions of water-rich strata, and its adaptability under other complex geological conditions is relatively weak. In addition, this system requires manual operation and monitoring, with a low degree of automation, increasing the need for manual intervention and potentially bringing safety hazards. At the same time, the response speed of the system is limited by the sampling frequency of the sensors and the processing ability of the industrial control computer, and may not fully meet the requirements of real-time control under rapidly changing pressure conditions.

[0005] The above problems indicate that the existing pressure maintaining systems for the air cushion chamber of shield machines still have significant deficiencies in terms of control accuracy, response speed, degree of automation, and adaptability to complex working conditions. Therefore, there is an urgent need to develop an efficient and intelligent pressure maintaining system that can optimize the control logic, improve the response speed and control accuracy, simplify the operation process, and enhance the adaptability of the system under various geological conditions to meet the requirements of modern tunnel construction for efficient and intelligent pressure maintaining systems. Summary of the Invention

[0006] Aiming at the deficiencies of the existing technology, the present invention provides a pressure maintaining system for the air cushion chamber of a shield machine. The specific technical solutions are as follows:

[0007] To achieve the above object, the present invention provides the following technical solutions: A pressure maintaining system for the air cushion chamber of a shield machine, including a main system and a standby system. The main system and the standby system share a differential pressure regulating device, a pressure reducing device, a control module and a pressure detecting device; the main system includes a first gas processing device, a first intake control valve, a first signal enhancer, a first exhaust control valve, a third signal enhancer, a first noise suppression device; the standby system includes a second gas processing device, a second intake control valve, a second signal enhancer, a second exhaust control valve, a fourth signal enhancer, a second noise suppression device.

[0008] Preferably, the differential pressure regulating device is arranged at the system inlet. The internal valve core adopts a double-cone structure design, and the cone angle is 45° to 60°. Its surface is coated with a wear-resistant coating, and the pressure balance is achieved by real-time monitoring of the pressure change between the main system and the standby system and adjusting the valve core position.

[0009] Preferably, the first gas processing device and the second gas processing device are respectively located on the intake main pipelines of the main system and the standby system. The built-in high-efficiency filter element is made of multi-layer composite materials and is used to remove impurities and moisture in the compressed air.

[0010] Preferably, the pressure reducing device is connected after the first gas processing device and the second gas processing device. The built-in spring mechanism is made of high-elastic alloy materials, and the diaphragm assembly is made of corrosion-resistant materials. The output pressure is dynamically adjusted to meet the system requirements.

[0011] Preferably, the first signal enhancer and the second signal enhancer are respectively configured on the first intake control valve and the second intake control valve. The internal circuit adopts a high-speed operational amplifier design and is used to amplify the control signal of the intake control valve.

[0012] Preferably, the first noise suppression device and the second noise suppression device are respectively located on the exhaust pipelines of the main system and the standby system. The internal sound-absorbing cavity is filled with porous sound-absorbing materials and is used to eliminate the noise during the exhaust process.

[0013] Preferably, when the main system is running, compressed air is filtered by the first gas treatment device and then enters the pressure reducing device. Subsequently, it enters the main system through the first intake control valve. The first signal booster amplifies the control signal of the first intake control valve. When the pressure in the system exceeds the set value, the first exhaust control valve opens, and the third signal booster amplifies the control signal of the first exhaust control valve. At the same time, the first noise suppression device eliminates the noise during the exhaust process.

[0014] Preferably, when the main system fails or needs maintenance, the differential pressure regulating device monitors the pressure change between the main system and the standby system in real time and adjusts the internal spool position to achieve pressure balance. Compressed air is filtered by the second gas treatment device and then enters the pressure reducing device. Subsequently, it enters the standby system through the second intake control valve. The second signal booster amplifies the control signal of the second intake control valve. When the pressure in the system exceeds the set value, the second exhaust control valve opens, and the fourth signal booster amplifies the control signal of the second exhaust control valve. At the same time, the second noise suppression device eliminates the noise during the exhaust process.

[0015] Preferably, the control module monitors the pressure changes in the main system and the standby system in real time through the pressure detection device and issues control commands according to the preset logic program to control the opening or closing of the first intake control valve, the second intake control valve, the first exhaust control valve, and the second exhaust control valve.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: By setting up the main system and the standby system and achieving pressure balance between the main and standby systems through the differential pressure regulating device, it avoids construction interruption caused by a single system failure; filters compressed air through the first gas treatment device and the second gas treatment device to remove impurities and moisture, ensuring the stability of system operation; dynamically adjusts the output pressure through the pressure reducing device to meet the system's requirements for different pressure ranges; significantly improves the system's response speed by amplifying the control signals of the intake control valves through the first signal booster and the second signal booster; eliminates the noise during the exhaust process through the first noise suppression device and the second noise suppression device, improving the working environment at the construction site. Through the above technical means, the present invention solves the problems of insufficient control accuracy, slow response speed, and inconvenient operation of the existing pressure maintaining system under complex working conditions, and at the same time enhances the adaptability of the system under various geological conditions, providing an efficient and intelligent pressure maintaining solution for modern tunnel construction. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is the overall structural schematic diagram of the present invention; Figure 2 is the internal structural schematic diagram of the differential pressure regulating device; Figure 3 Schematic cross-sectional structure diagram of a gas treatment device; Figure 4 Internal structure diagram of a noise suppression device.

[0018] In the figure: 1. Differential pressure regulating device; 2. First gas treatment device; 3. Pressure reduction device; 4. Control module; 5. Pressure detection device; 6. Second gas treatment device; 7. First intake control valve; 8. First signal booster; 9. Second intake control valve; 1; 0. Second signal booster; 11. First noise suppression device; 12. First exhaust control valve; 13. Third signal booster; 14. Second exhaust control valve; 15. Fourth signal booster; 16. Second noise suppression device; 17. Compressed air. Detailed implementation mode

[0019] The present invention provides a pressure maintaining system for the air cushion bin of a shield machine. The following combines the attached Figures 1-4 to elaborate in detail on the specific implementation mode of the present invention. As Figure 1 shown, the pressure maintaining system includes a main system and a standby system, and both share the differential pressure regulating device 1, the pressure reduction device 2, the control module 4, and the pressure detection device 5. The main components of the main system include the first gas treatment device 3, the first intake control valve 7, the first signal booster 8, the first exhaust control valve 12, the third signal booster 13, and the first noise suppression device 11; the main components of the standby system include the second gas treatment device 6, the second intake control valve 9, the second signal booster 10, the second exhaust control valve 14, the fourth signal booster 15, and the second noise suppression device 16. All these components are connected through pipelines or electrically to form a complete system and work according to a specific logical sequence.

[0020] [[ID=१९]]The differential pressure regulating device 1 is arranged at the system inlet, and its internal structure is designed with a double-cone valve core structure, as [[ID=२०]] Figure 2 [[ID=२१]]shown. The double-cone valve core is composed of two symmetrical conical parts, and it can achieve pressure balance between the main system and the standby system by adjusting the position of the valve core. When there is a pressure difference between the main system and the standby system, the differential pressure regulating device 1 dynamically adjusts the position of the valve core by real-time monitoring of the pressure change, making the pressures of the two systems tend to be the same. This design ensures that there will be no sudden pressure change when the main system switches to the standby system. The outlets of the differential pressure regulating device 1 are respectively connected to the inlets of the first gas treatment device 3 and the second gas treatment device 6, thereby distributing the compressed air 17 to the main system and the standby system. [[ID=२२]] [[ID=२३]]

[0021] The first gas treatment device 3 and the second gas treatment device 6 are respectively located on the intake main pipelines of the main system and the standby system, and their built-in high-efficiency filters are made of multi-layer composite materials. These filters have a high filtration accuracy and can effectively remove impurities and moisture in the compressed air 17. The outlet of the first gas treatment device 3 is connected to the inlet of the pressure reduction device 2. Similarly, the outlet of the second gas treatment device 6 is also connected to the inlet of the pressure reduction device 2. The internal structure of the pressure reduction device 2 is as Figure 3 shown. Its core components include a spring mechanism and a diaphragm assembly. The spring mechanism is made of a high-elastic alloy material and has good elasticity and durability; the diaphragm assembly is made of a corrosion-resistant material and can maintain stable performance during long-term use. The pressure reduction device 2 dynamically adjusts the output pressure to a range suitable for system use through the synergistic effect of the spring mechanism and the diaphragm assembly. The compressed air 17 processed by the pressure reduction device 2 enters the intake control valves of the main system and the standby system respectively.

[0022] The intake control of the main system is completed by the first intake control valve 7, and the first signal booster 8 is configured on the first intake control valve 7. The internal circuit of the first signal booster 8 is designed with a high-speed operational amplifier and can amplify the control signal of the first intake control valve 7, thereby improving the response speed. The outlet of the first intake control valve 7 is connected to the gas path of the main system, and the compressed air 17 passing through the first intake control valve 7 enters the subsequent pipeline of the main system. When the pressure in the main system exceeds the set value, the first exhaust control valve 12 opens to release the excess pressure. The control signal of the first exhaust control valve 12 is amplified by the third signal booster 13 to accelerate the exhaust speed. Figure 4 As shown, the outlet of the first exhaust control valve 12 is connected to the inlet of the first noise suppression device 11, and the internal sound-absorbing cavity of the first noise suppression device 11 is filled with porous sound-absorbing materials, which can effectively eliminate the noise during the exhaust process.

[0023] The operating principle of the standby system is similar to that of the main system, but its main components are the second intake control valve 9, the second signal booster 10, the second exhaust control valve 14, and the second noise suppression device 16. The inlet of the second intake control valve 9 is connected to the outlet of the pressure reduction device 2, and its outlet is connected to the gas path of the standby system. The second signal booster 10 is configured on the second intake control valve 9 and is used to amplify the control signal of the second intake control valve 9. When the pressure in the standby system exceeds the set value, the second exhaust control valve 14 opens to release the excess pressure. The control signal of the second exhaust control valve 14 is amplified by the fourth signal booster 15 to accelerate the exhaust speed. The outlet of the second exhaust control valve 14 is connected to the inlet of the second noise suppression device 16, and the internal sound-absorbing cavity of the second noise suppression device 16 is also filled with porous sound-absorbing materials, which can effectively eliminate the noise during the exhaust process.

[0024] During the actual construction process, the main system is usually in the working state, while the standby system serves as an emergency guarantee. When the main system is operating normally, compressed air 17 enters the differential pressure regulating device 1 from an external air source. After being regulated by the double-cone valve core, it enters the first gas treatment device 3. The first gas treatment device 3 preliminarily filters the compressed air 17 to remove impurities and moisture therein. The filtered compressed air 17 enters the pressure reducing device 2, and through the dynamic adjustment of the spring mechanism and the diaphragm assembly, the output pressure is controlled within the range suitable for system use. Subsequently, the compressed air 17 enters the main system through the first intake control valve 7, and the first signal booster 8 amplifies the control signal of the first intake control valve 7 to improve the response speed. If the pressure in the main system exceeds the set value, the first exhaust control valve 12 opens, and the third signal booster 13 amplifies the control signal of the first exhaust control valve 12 to accelerate the exhaust speed. At the same time, the first noise suppression device 11 eliminates the noise during the exhaust process.

[0025] When the main system fails or needs maintenance, the standby system will automatically switch to the working state. At this time, the differential pressure regulating device 1 monitors the pressure change between the main system and the standby system in real time and adjusts the internal valve core position to achieve pressure balance. Compressed air 17 enters the differential pressure regulating device 1 from an external air source. After being regulated by the double-cone valve core, it enters the second gas treatment device 6. The second gas treatment device 6 filters the compressed air 17 to remove impurities and moisture therein. The filtered compressed air 17 enters the pressure reducing device 2, and through the dynamic adjustment of the spring mechanism and the diaphragm assembly, the output pressure is controlled within the range suitable for system use. Subsequently, the compressed air 17 enters the standby system through the second intake control valve 9, and the second signal booster 10 amplifies the control signal of the second intake control valve 9 to improve the response speed. If the pressure in the standby system exceeds the set value, the second exhaust control valve 14 opens, and the fourth signal booster 15 amplifies the control signal of the second exhaust control valve 14 to accelerate the exhaust speed. At the same time, the second noise suppression device 16 eliminates the noise during the exhaust process.

[0026] The operation process of the entire system is uniformly managed by the control module 4. The control module 4 monitors the pressure changes in the main system and the standby system in real time through the pressure detection device 5, and issues control instructions according to the preset logic program. For example, when the pressure in the main system is lower than the set value, the control module 4 issues an instruction to open the first intake control valve 7; when the pressure in the main system is higher than the set value, the control module 4 issues an instruction to open the first exhaust control valve 12. Similarly, when the pressure in the standby system is lower than the set value, the control module 4 issues an instruction to open the second intake control valve 9; when the pressure in the standby system is higher than the set value, the control module 4 issues an instruction to open the second exhaust control valve 14. In this way, the system can achieve precise pressure control, so as to meet the requirements of the shield machine air cushion chamber under different working conditions.

[0027] In practical applications, the pressure maintaining system of the present invention can be widely applied to tunnel construction under various complex geological conditions. For example, when constructing in soft soil layers or water-bearing strata, the shield machine air cushion chamber needs to maintain a stable pressure to prevent formation collapse or water inrush. The present invention sets up a main system and a standby system, and realizes the pressure balance between the main and standby systems through the differential pressure regulating device 1, avoiding construction interruption caused by a single system failure. In addition, the first gas treatment device 3 and the second gas treatment device 6 filter the compressed air 17 to remove impurities and moisture therein, ensuring the stability of the system operation. The pressure reduction device 2 dynamically adjusts the output pressure to meet the system's requirements for different pressure ranges. The first signal booster 8 and the second signal booster 10 amplify the control signals of the intake control valves, significantly improving the response speed of the system. The first noise suppression device 11 and the second noise suppression device 16 eliminate the noise during the exhaust process, improving the working environment at the construction site. Through the above technical means, the present invention solves the problems of insufficient control accuracy, slow response speed and inconvenient operation of the existing pressure maintaining system under complex working conditions, and at the same time enhances the adaptability of the system under various geological conditions, providing an efficient and intelligent pressure maintaining solution for modern tunnel construction.

[0028] In order to better enable relevant personnel in the technical field to fully understand and implement the present invention, the following further supplements and explains the specific implementation principle of the present invention in combination with a specific application scenario.

[0029] In a certain tunnel construction project, the shield machine air cushion chamber needs to maintain a stable internal pressure to ensure the stability of the excavation face. The geological conditions of this construction area are complex, including soft soil layers and water-bearing strata. Therefore, higher requirements are put forward for the control accuracy, response speed and adaptability of the pressure maintaining system. Based on the pressure maintaining system provided by the present invention, its operation process is as follows: First, compressed air 17 enters the differential pressure regulating device 1 from an external air source. The differential pressure regulating device 1 adopts a double-cone valve core structure design inside. By real-time monitoring the pressure difference between the main system and the standby system, it dynamically adjusts the position of the valve core, thus achieving pressure balance between the two systems. This design ensures that even during the process of switching the main system to the standby system, the construction safety will not be affected by sudden pressure changes. The compressed air 17 processed by the differential pressure regulating device 1 is respectively distributed to the inlets of the first gas treatment device 3 and the second gas treatment device 6.

[0030] Subsequently, the compressed air 17 enters the first gas treatment device 3 for preliminary filtration. The first gas treatment device 3 is internally equipped with multi-layer composite material filter elements, which can effectively remove impurities and moisture in the compressed air (17), thus ensuring that the subsequent pipelines and components are not contaminated or corroded. The filtered compressed air 17 flows into the pressure reducing device 2, and through the coordinated action of the spring mechanism and the diaphragm assembly, the output pressure is dynamically adjusted to a range suitable for system use. This dynamic adjustment mechanism enables the system to adapt to the pressure requirements under different working conditions and at the same time avoids control errors caused by pressure fluctuations.

[0031] Next, the compressed air 17 processed by the pressure reducing device 2 enters the main system through the first intake control valve 7. The first signal booster 8 is configured on the first intake control valve 7. Its internal circuit adopts a high-speed operational amplifier design. By amplifying the control signal of the first intake control valve 7, it significantly improves the response speed of the valve. When the pressure in the main system is lower than the set value, the control module 4 issues an instruction according to the data fed back by the pressure detection device 5, causing the first intake control valve 7 to open quickly to replenish the compressed air 17 in time; when the pressure in the main system is higher than the set value, the control module 4 issues an instruction to open the first exhaust control valve 12, and the third signal booster 13 amplifies the control signal to accelerate the exhaust speed. At the same time, the first noise suppression device 11 eliminates the noise generated during the exhaust process through the porous sound-absorbing material filled inside, improving the working environment at the construction site.

[0032] When the main system fails or needs maintenance, the standby system automatically switches to the working state. At this time, the differential pressure regulating device 1 continues to monitor the pressure change between the main system and the standby system, and realizes the pressure balance between the two systems by adjusting the position of the double-cone valve core. The compressed air 17 is distributed by the differential pressure regulating device 1 and then enters the second gas treatment device 6 to complete the filtration treatment of impurities and moisture. Subsequently, the compressed air 17 is dynamically regulated in pressure by the pressure reducing device 2 and then enters the standby system through the second intake control valve 9. The second signal amplifier 10 amplifies the control signal of the second intake control valve 9 to improve its response speed. If the pressure in the standby system exceeds the set value, the second exhaust control valve 14 opens, and the fourth signal amplifier 15 amplifies its control signal to accelerate the exhaust speed. At the same time, the second noise suppression device 16 eliminates the exhaust noise.

[0033] The operation process of the entire system is uniformly managed by the control module 4. The control module 4 monitors the pressure changes in the main system and the standby system in real time through the pressure detection device 5 and issues control instructions according to the preset logic program. For example, during the normal operation of the main system, when it is detected that the system pressure is lower than the target value, the control module 4 issues an instruction to open the first intake control valve 7 to supplement the compressed air 17; when it is detected that the system pressure is higher than the target value, an instruction is issued to open the first exhaust control valve 12 to release the excess pressure. Similarly, when the standby system is in the working state, the control module 4 also issues corresponding instructions according to the pressure detection data to ensure the stable operation of the standby system.

[0034] It can be seen from the above operation steps that the present invention sets up a main system and a standby system, and uses the differential pressure regulating device 1 to achieve the pressure balance between the two systems, effectively avoiding the risk of construction interruption caused by the failure of a single system. At the same time, the first gas treatment device 3 and the second gas treatment device 6 filter the compressed air 17 to remove impurities and moisture in it, ensuring the stability of the system operation. The pressure reducing device 2 dynamically adjusts the output pressure through the cooperation of the spring mechanism and the diaphragm assembly, meeting the system's requirements for different pressure ranges. In addition, the first signal amplifier 8 and the second signal amplifier 10 amplify the control signals of the intake control valves, significantly improving the response speed of the system; the first noise suppression device 11 and the second noise suppression device 16 eliminate the exhaust noise through porous sound-absorbing materials, improving the working environment at the construction site.

[0035] In summary, the present invention solves the problems of insufficient control accuracy, slow response speed, and inconvenient operation existing in the existing pressure-holding system under complex working conditions through the above technical means. At the same time, it enhances the adaptability of the system under various geological conditions, providing an efficient and intelligent pressure-holding solution for modern tunnel construction.

[0036] Although embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A pressure maintaining system for the air cushion bin of a shield machine, characterized in that: It includes a main system and a standby system. The main system and the standby system share a differential pressure regulating device (1), a pressure reducing device (3), a control module (4), and a pressure detection device (5); the main system includes a first gas treatment device (2), a first intake air control valve (7), a first signal booster (8), a first exhaust control valve (12), a third signal booster (13), and a first noise suppression device (11); the standby system includes a second gas treatment device (6), a second intake air control valve (9), a second signal booster (10), a second exhaust control valve (14), a fourth signal booster (15), and a second noise suppression device (16).

2. The pressure-holding system according to claim 1, wherein: The differential pressure regulating device (1) is arranged at the system inlet. The internal valve core thereof adopts a double-cone structure design, and the cone angle is 45° to 60°. Its surface is coated with a wear-resistant coating, and it realizes pressure balance by monitoring the pressure change between the main system and the standby system in real time and adjusting the valve core position.

3. The pressure maintaining system for the air cushion bin of a shield machine according to claim 1, characterized in that: The first gas treatment device (2) and the second gas treatment device (6) are respectively located on the intake main pipelines of the main system and the standby system. The built-in high-efficiency filter element thereof is made of multi-layer composite materials and is used to remove impurities and moisture in the compressed air (17).

4. A pressure maintaining system for the air cushion bin of a shield machine according to claim 1, characterized in that: The pressure reducing device (3) is connected after the first gas treatment device (2) and the second gas treatment device (6). The built-in spring mechanism thereof is made of a high-elastic alloy material, and the diaphragm assembly is made of a corrosion-resistant material. It dynamically adjusts the output pressure to meet the system requirements.

5. A pressure maintaining system for the air cushion bin of a shield machine according to claim 1, characterized in that: The first signal booster (8) and the second signal booster (10) are respectively configured on the first intake air control valve (7) and the second intake air control valve (9). The internal circuit thereof adopts a high-speed operational amplifier design and is used to amplify the control signal of the intake air control valve.

6. A pressure maintaining system for the air cushion bin of a shield machine according to claim 1, characterized in that: The first noise suppression device (11) and the second noise suppression device (16) are respectively located on the exhaust pipelines of the main system and the standby system. The internal silencing cavity thereof is filled with porous sound-absorbing materials and is used to eliminate the noise during the exhaust process.

7. The pressure maintaining system for the air cushion bin of a shield machine according to claim 1, characterized in that: When the main system is operating, the compressed air (17) enters the pressure reducing device (3) after being filtered by the first gas treatment device (2), and then enters the main system through the first intake air control valve (7). The first signal booster (8) amplifies the control signal of the first intake air control valve (7). When the pressure in the system exceeds the set value, the first exhaust control valve (12) opens, and the third signal booster (13) amplifies the control signal of the first exhaust control valve (12). At the same time, the first noise suppression device (11) eliminates the noise during the exhaust process.

8. A pressure maintaining system for the air cushion bin of a shield machine according to claim 1, characterized in that: When the main system fails or requires maintenance, the pressure difference regulating device (1) monitors the pressure change between the main system and the standby system in real time and adjusts the position of the internal valve core to achieve pressure balance. The compressed air (17) enters the pressure reducing device (3) after being filtered by the second gas treatment device (6), and then enters the standby system through the second intake control valve (9). The second signal amplifier (10) amplifies the control signal of the second intake control valve (9). When the pressure in the system exceeds the set value, the second exhaust control valve (14) opens, and the fourth signal amplifier (15) amplifies the control signal of the second exhaust control valve (14). At the same time, the second noise suppression device (16) eliminates the noise during the exhaust process.

9. The pressure maintaining system for the air cushion bin of a shield machine according to claim 1, characterized in that: The control module (4) monitors the pressure changes in the main system and the standby system in real time through the pressure detection device (5), and issues control instructions according to the preset logic program to control the opening or closing of the first intake control valve (7), the second intake control valve (9), the first exhaust control valve (12), and the second exhaust control valve (14).

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