Liquid level detection device and shield machine air cushion chamber using the same

Abstract

The present invention relates to the field of liquid level detection technology for liquid storage tanks and its application in the field of liquid level detection technology during shield tunneling. The purpose of the present invention is to provide a liquid level detection device and a shield machine air cushion tank using the liquid level detection device to solve the technical problems that existing liquid level detection technology cannot observe the internal working conditions of the liquid storage tank and is prone to causing a limited detection range and inaccurate results. The liquid level detection device includes a controller, a sealed box, at least two light emitters, and an imaging device. The light emitter is used to emit a light beam to the liquid surface in the tank to form a light spot on the liquid surface. The imaging device is used to obtain an image of the liquid surface in the tank containing the light spot. The imaging device and the light emitter are assembled in the sealed box. At least two light emitters are installed on both sides of the imaging device. The sealed box is fixed to the top of the liquid storage tank so that the imaging device and the light emitter are at the top of the liquid storage tank. The bottom plate of the sealed box has a light-transmitting portion corresponding to the imaging device and the light emitter.

Description

Technical Field

[0001] The present invention relates to a liquid level detection technology for a liquid storage bin and the application of the technology in the field of liquid level detection technology in shield construction, and in particular to an air cushion bin of a shield machine and a liquid level detection device thereof. Background Art

[0002] With the annual expansion of underground construction projects in my country, such as urban subways and cross-river and cross-sea tunnels, shield construction methods are increasingly being used in these projects due to their high efficiency, high safety, and environmental friendliness. Among shield construction methods, slurry shields offer high precision in controlling excavation face pressure and ground subsidence, making them widely used in complex geological conditions and underwater projects spanning rivers and streams. In slurry shields, the air cushion tank level directly affects the support pressure on the excavation face, making continuous and accurate measurement of the air cushion tank level crucial for slurry shield construction.

[0003] Due to the harsh environment inside the air cushion tank, the equipment needs to be operated under pressure after being damaged, which is dangerous and not conducive to construction workers entering the tank under pressure. The liquid level of the air cushion tank needs to be measured by liquid level detection equipment, such as a rope level gauge, radar level gauge or point level gauge.

[0004] A Chinese patent document with the publication number CN212110213U discloses a capacitive liquid level sensor that uses changes in capacitance to measure the height of the liquid. During operation, a metal rod is inserted into the liquid in the container, with the metal rod acting as one electrode of the capacitor and the container wall acting as the other electrode. The medium between the two electrodes is the liquid and the gas above it, where the dielectric constant of the liquid is different from the dielectric constant of the gas. When the liquid level rises or falls, the total dielectric constant between the two electrodes changes accordingly, and the capacitance also changes. Therefore, the liquid level can be measured based on the change in capacitance between the two electrodes. The sensitivity of a capacitive liquid level sensor depends on the difference in the dielectric constants of the two media. Accurate measurements can only be made when the two media remain constant. However, changes in the temperature and density of the liquid to be measured will cause changes in the dielectric constant. In this case, the measurement results of the capacitive liquid level sensor will have errors, resulting in inaccurate measurements.

[0005] Chinese patent publication number CN109443481A discloses a closed pressure vessel measurement device and method. The device installs sensors at three different heights on the rear bulkhead of an air cushion chamber. The two lower sensors are immersed in the liquid, while the upper sensor is installed at the highest point of the air cushion chamber. The two lower sensors calculate the liquid density, and the liquid level is calculated using the upper sensor. This method requires both lower sensors to be immersed in the liquid. If the liquid level is lower than one of the sensors, effective measurement cannot be guaranteed, which poses certain limitations for liquid level measurement.

[0006] Chinese patent publication number CN211855507U discloses a laser level monitoring system for shield tunneling. This system uses a laser rangefinder installed on the tank wall, combined with a level tube and float, to monitor the liquid level in the air cushion tank. While this system improves level detection accuracy, it lacks visualization capabilities, preventing visibility into the air cushion tank interior.

[0007] In summary, in the existing technology, when performing liquid level detection on a liquid storage tank containing liquid, especially when detecting the mud level in the air cushion tank of a shield machine, only simple numerical measurements can be performed, and the internal working conditions of the liquid storage tank cannot be directly observed. In addition, there are problems such as limited detection range and inaccurate detection results, which affect construction operations. Summary of the Invention

[0008] The present invention aims to provide a liquid level detection device to address the technical problems of existing detection devices, which are unable to observe the internal working conditions of the liquid storage tank, and are prone to limited detection range and inaccurate detection results. Furthermore, the present invention aims to provide an air cushion tank for a shield machine to address the above-mentioned problems.

[0009] To achieve the above-mentioned purpose, the present invention provides a technical solution of a liquid level detection device:

[0010] A liquid level detection device includes a controller, a sealed box, and at least two light emitters and an imaging device. The light emitters and the imaging device are both connected to the controller. The light emitters are used to emit light beams toward the liquid surface in the liquid storage tank to form two or more light spots on the liquid surface. The imaging device is used to obtain an image of the liquid surface in the tank containing the light spots and provide it to the controller. The sealed box is a closed box. The imaging device and the light emitters are assembled in the sealed box. At least two light emitters are installed on both sides of the imaging device. The sealed box is used to be fixedly connected to the top of the liquid storage tank so that the imaging device and The light emitter is located at the top of the liquid storage tank; the bottom plate of the sealed box has a light-transmitting portion corresponding to the imaging device and the light emitter; the controller is used to perform the following method: analyzing the image to obtain the image distance d between the images formed by the two light spots on the photosensitive surface of the imaging device, calculating the height h = f*d0 / d between the imaging device lens and the liquid level in the tank, and calculating the height of the liquid level in the tank based on the height h, wherein f and d0 are respectively the known focal length of the imaging device lens and the actual distance between the two light spots, and the actual distance between the two light spots is the horizontal distance between the two light emitters on the bottom plate of the sealed box.

[0011] Beneficial effects: In order to achieve continuous, accurate, and observable detection of the liquid level in the liquid storage tank, the present invention sets a sealed box above the liquid storage tank, and then sets a light emitter and an imaging device in the sealed box, so that a light spot can be emitted to the liquid surface in the tank through the light emitter, and the imaging device is used to collect the muddy and water surface image, and the light spot in the muddy and water surface image is analyzed to obtain the distance between the images formed by the light spot on the photosensitive surface of the imaging device. According to the imaging ratio principle, the height of the lens of the imaging device from the muddy and water surface is calculated, and the height of the lens from the muddy and water surface is subtracted from the installation height of the imaging device to obtain the liquid level of the muddy and water surface. At the same time, the muddy and water surface image collected by the imaging device can be used to visualize the environment in the liquid storage tank. The sealed box in the present invention is a closed box that ensures that the light emitter and the imaging device are separated from the environment inside the liquid storage tank. The light-transmitting part enables both the imaging device and the light emitter to illuminate the liquid surface, and can observe and continuously measure the liquid level height in various liquid storage tanks. The working environment of the internal components of the detection device is sealed, and the system complexity and cost are reduced, which effectively solves the technical problems in the prior art that the detection device cannot observe the internal working conditions of the liquid storage tank and easily causes limited detection range and inaccurate detection results.

[0012] Preferably, the imaging device is assembled in a sealed box through an imaging device mounting assembly. The imaging device mounting assembly includes a protective shell and a vibration-damping structure. The imaging device is fixedly assembled in the protective shell. The protective shell includes an upper platform and a lower platform that are separated and interconnected. The upper platform is used to connect to the top of the sealed box, and the lower platform is used to connect to the bottom plate of the sealed box. The vibration-damping structure includes a support frame and a vibration damper. Each support frame surrounds the outer circumference of the upper platform. The upper end of each support frame is fixedly connected to the top of the sealed box, and the lower end of each support frame is connected to the bottom of the upper platform through the vibration damper. The imaging device is firmly assembled in the sealed box by the imaging device mounting assembly to ensure the stable operation of the imaging device. The separately arranged protective shell is very convenient to connect and disassemble, which is conducive to the installation of the imaging device in the protective shell. The vibration-damping structure can effectively reduce vibration and protect the protective shell, thereby increasing the durability and safety of the imaging device after assembly.

[0013] Preferably, the lower platform has a lens opening at its lower end, a glass baffle fixed in the lens opening, a first opening corresponding to the lower platform fixed in the base plate, a lens protective glass fixed in the first opening to form the light-transmitting portion corresponding to the imaging device, the lens protective glass in contact with the outside of the sealed box, and a fixed connection between the lens protective glass and the glass baffle, thereby achieving fixed assembly of the lower platform on the base plate. The glass baffle provides sealing protection for the lens at the lower end of the imaging device, and the light-transmitting portion formed by the first opening on the base plate and the lens protective glass ensures that the imaging device can illuminate the liquid surface in the chamber. The light-transmitting portion has a simple structure, good sealing performance, and high connection strength.

[0014] Preferably, a sealing ring is press-fitted between the lens cover glass and the glass baffle. The sealing ring comprises an annular gasket and a sealing cylinder surrounding the outer periphery of the annular gasket. The annular gasket is sandwiched between the lens cover glass and the glass baffle, while the sealing cylinder surrounds the outer periphery of the gap between the lens cover glass and the glass baffle, with the lower end of the sealing cylinder pressing against the base plate. The sealing ring not only ensures a tight seal after the lens cover glass and the glass baffle are connected, but also provides a certain degree of elasticity to the fit between the lens cover glass and the glass baffle, enhancing the vibration reduction effect and making the connection and assembly between the lower platform and the base plate more stable.

[0015] Preferably, a light-filling layer is provided on the upper surface of the lens protective glass, and the glass baffle, the light-filling layer, and the lens protective glass are fixed to the base plate via bolts. The light-filling layer can supplement the camera's illumination, enhancing the light transmittance of the imaging device and enabling the imaging device to adapt to liquid storage tanks with relatively poor internal environments.

[0016] Preferably, an upper platform flange is provided at the bottom end of the upper platform, and a lower platform flange is provided at the top end of the lower platform. The upper and lower platform flanges are connected, and the vibration damper is fixed to the upper platform flange. The flange connection is tightly fitted and the connection assembly is stable. The arrangement of the upper and lower platform flanges ensures a secure assembly of the protective housing as a whole. The flange connection is also convenient for installation and removal, facilitating the assembly and placement of the imaging device within the protective housing.

[0017] Preferably, a self-cleaning nozzle is provided on the outer surface of the bottom plate of the sealed box. The self-cleaning nozzle is positioned adjacent to the light-transmitting portion, with the nozzle directed toward the light-transmitting portion. The self-cleaning nozzle enables the liquid level detection device to adapt to liquid storage tanks operating in challenging environmental conditions, allowing for timely cleaning of the protective glass in the light-transmitting portion to ensure continuous illumination of the liquid surface within the tank.

[0018] Preferably, the bottom plate is provided with a second opening corresponding to the light emitter. A laser shielding glass is provided in the second opening to form the light-transmitting portion corresponding to the light emitter. The laser shielding glass is in contact with the outside of the sealed box. The second opening and the laser shielding glass not only allow the light emitter to illuminate the liquid surface within the chamber, but also seal the second opening with the laser shielding glass. This simplifies the structure of the light-transmitting portion and provides high sealing and connection strength.

[0019] Preferably, the sealed box further includes a top plate and side plates detachably connected between the top and bottom plates. The side plates are provided with signal transmission interfaces for connecting signal lines from the light emitter and imaging device to and from the sealed box. The detachable sealed box facilitates the installation of various devices and connection structures within the sealed box, and the signal transmission interfaces facilitate wiring and control.

[0020] The technical solution of a shield machine air cushion chamber provided by the present invention is:

[0021] A shield machine air cushion chamber, including a chamber body constituting a liquid storage chamber, and also including a liquid level detection device installed at the top of the chamber body, the liquid level detection device is used to obtain the liquid level height of the mud and water in the shield machine air cushion chamber, the liquid level detection device includes a controller, a sealing box, and also includes at least two light emitters and an imaging device, the light emitters and the imaging device are both connected to the controller, the light emitters are used to emit light beams to the liquid surface in the chamber and form two or more light spots on the liquid surface, the imaging device is used to obtain an image of the liquid surface in the chamber containing the light spots and provide it to the controller; the sealing box is a closed box, the imaging device and the light emitter are installed in the sealing box, and at least two light emitters are installed On both sides of the imaging device, a sealed box is used to be fixedly connected to the top of the liquid storage tank so that the imaging device and the light emitter are at the top of the liquid storage tank; the bottom plate of the sealed box has a light-transmitting portion corresponding to the imaging device and the light emitter; the controller is used to execute the following method: analyze the image, obtain the image distance d between the images formed by the two light spots on the photosensitive surface of the imaging device, calculate the height h = f*d0 / d of the imaging device lens from the liquid level in the tank, and calculate the height of the liquid level in the tank based on the height h, where f and d0 are respectively the known focal length of the imaging device lens and the actual distance between the two light spots, and the actual distance between the two light spots is the horizontal distance between the two light emitters on the bottom plate of the sealed box.

[0022] Beneficial effects: The present invention sets a liquid level detection device in the air cushion chamber of the shield machine, so that the liquid level height of the mud and water surface in the air cushion chamber can be measured by the liquid level detection device. The light emitter emits a light spot to the mud and water surface, and an imaging device is used to collect the mud and water surface image. By analyzing the light spot in the mud and water surface image, the distance between the images formed by the light spot on the photosensitive surface of the imaging device is obtained. According to the imaging ratio principle, the height of the lens of the imaging device from the mud and water surface is calculated. The height of the mud and water surface is obtained by subtracting the height of the lens from the mud and water surface from the installation height of the imaging device. At the same time, the mud and water surface image collected by the imaging device can be used to visualize the environment inside the air cushion chamber. The sealed box is a closed box that ensures that the light emitter and imaging device are separated from the environment inside the liquid storage tank. The light-transmitting part enables both the imaging device and the light emitter to illuminate the liquid surface, and can observe and continuously measure the mud and water level in the air cushion tank. The system has a good working environment, reduced system complexity and cost, and effectively solves the technical problems in the existing technology that the detection device cannot observe the internal working conditions of the shield machine air cushion tank and easily causes limited detection range and inaccurate detection results.

[0023] Preferably, the imaging device is assembled in a sealed box through an imaging device mounting assembly. The imaging device mounting assembly includes a protective shell and a vibration-damping structure. The imaging device is fixedly assembled in the protective shell. The protective shell includes an upper platform and a lower platform that are separated and interconnected. The upper platform is used to connect to the top of the sealed box, and the lower platform is used to connect to the bottom plate of the sealed box. The vibration-damping structure includes a support frame and a vibration damper. Each support frame surrounds the outer circumference of the upper platform. The upper end of each support frame is fixedly connected to the top of the sealed box, and the lower end of each support frame is connected to the bottom of the upper platform through the vibration damper. The imaging device is firmly assembled in the sealed box by the imaging device mounting assembly to ensure the stable operation of the imaging device. The separately arranged protective shell is very convenient to connect and disassemble, which is conducive to the installation of the imaging device in the protective shell. The vibration-damping structure can effectively reduce vibration and protect the protective shell, thereby increasing the durability and safety of the imaging device after assembly.

[0024] Preferably, the lower platform has a lens opening at its lower end, a glass baffle fixed in the lens opening, a first opening corresponding to the lower platform fixed in the base plate, a lens protective glass fixed in the first opening to form the light-transmitting portion corresponding to the imaging device, the lens protective glass in contact with the outside of the sealed box, and a fixed connection between the lens protective glass and the glass baffle, thereby achieving fixed assembly of the lower platform on the base plate. The glass baffle provides sealing protection for the lens at the lower end of the imaging device, and the light-transmitting portion formed by the first opening on the base plate and the lens protective glass ensures that the imaging device can illuminate the liquid surface in the chamber. The light-transmitting portion has a simple structure, good sealing performance, and high connection strength.

[0025] Preferably, a sealing ring is press-fitted between the lens cover glass and the glass baffle. The sealing ring comprises an annular gasket and a sealing cylinder surrounding the outer periphery of the annular gasket. The annular gasket is sandwiched between the lens cover glass and the glass baffle, while the sealing cylinder surrounds the outer periphery of the gap between the lens cover glass and the glass baffle, with the lower end of the sealing cylinder pressing against the base plate. The sealing ring not only ensures a tight seal after the lens cover glass and the glass baffle are connected, but also provides a certain degree of elasticity to the fit between the lens cover glass and the glass baffle, enhancing the vibration reduction effect and making the connection and assembly between the lower platform and the base plate more stable.

[0026] Preferably, a light-filling layer is provided on the upper surface of the lens protective glass, and the glass baffle, the light-filling layer, and the lens protective glass are fixed to the base plate via bolts. The light-filling layer can supplement the camera's illumination, enhancing the light transmittance of the imaging device and enabling the imaging device to adapt to liquid storage tanks with relatively poor internal environments.

[0027] Preferably, an upper platform flange is provided at the bottom end of the upper platform, and a lower platform flange is provided at the top end of the lower platform. The upper and lower platform flanges are connected, and the vibration damper is fixed to the upper platform flange. The flange connection is tightly fitted and the connection assembly is stable. The arrangement of the upper and lower platform flanges ensures a secure assembly of the protective housing as a whole. The flange connection is also convenient for installation and removal, facilitating the assembly and placement of the imaging device within the protective housing.

[0028] Preferably, a self-cleaning nozzle is provided on the outer surface of the bottom plate of the sealed box. The self-cleaning nozzle is positioned adjacent to the light-transmitting portion, with the nozzle directed toward the light-transmitting portion. The self-cleaning nozzle enables the liquid level detection device to adapt to liquid storage tanks operating in challenging environmental conditions, allowing for timely cleaning of the protective glass in the light-transmitting portion to ensure continuous illumination of the liquid surface within the tank.

[0029] Preferably, the bottom plate is provided with a second opening corresponding to the light emitter. A laser shielding glass is provided in the second opening to form the light-transmitting portion corresponding to the light emitter. The laser shielding glass is in contact with the outside of the sealed box. The second opening and the laser shielding glass not only allow the light emitter to illuminate the liquid surface within the chamber, but also seal the second opening with the laser shielding glass. This simplifies the structure of the light-transmitting portion and provides high sealing and connection strength.

[0030] Preferably, the sealed box further includes a top plate and side plates detachably connected between the top and bottom plates. The side plates are provided with signal transmission interfaces for connecting signal lines from the light emitter and imaging device to and from the sealed box. The detachable sealed box facilitates the installation of various devices and connection structures within the sealed box, and the signal transmission interfaces facilitate wiring and control. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a schematic structural diagram of the liquid level detection device in Example 1 provided by the present invention;

[0032] Figure 2 for Figure 1 Schematic diagram of the structure of the sealed box in the liquid level detection device after it is disassembled;

[0033] Figure 3 A bottom view of the liquid level detection device in Example 1 provided by the present invention;

[0034] Figure 4 This is a schematic diagram of the installation positions of the industrial camera and laser in Example 1 provided by the present invention;

[0035] Figure 5 This is a flowchart of the shield machine air cushion chamber liquid level detection method in Example 1 provided by the present invention;

[0036] Figure 6This is a schematic diagram of the principle of extracting the region of interest in an image in Example 1 provided by the present invention;

[0037] Figure 7 This is a schematic diagram of the principle of extracting the red channel in an image in Example 1 provided by the present invention;

[0038] Figure 8 This is a schematic diagram of calculating the distance between the light spot centers in Example 1 provided by the present invention;

[0039] Figure 9 This is a schematic diagram of the liquid level calculation principle in Example 1 provided by the present invention;

[0040] Figure 10 This is a schematic diagram of the bilinear interpolation principle when calculating the pixel value of the target point in Example 1 provided by the present invention.

[0041] Description of reference numerals:

[0042] 1. Sealing box; 2. Sealing groove; 3. Top plate; 4. Bottom plate; 5. Side plate; 6. Device fixing bracket; 7. Protective shell; 8. Upper platform; 801, upper platform flange; 9. Lower platform; 901, lower platform flange; 10. Glass baffle; 11. Fill light layer; 12. Lens protective glass; 13. Self-cleaning nozzle; 14. Support frame; 15. Vibration absorber; 16. Laser; 17. Transmitter fixing bracket; 18. Industrial camera; 19. Signal transmission interface; 20. Connecting bolt; 21. Photosensitive surface; 22. Mud and water level; 23. Light spot; 24. Camera connection port; 25. Water inlet; 26. Sealing ring; 27. Laser protective glass; 28. Industrial lens. DETAILED DESCRIPTION

[0043] In order to make the objectives, technical solutions, and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only intended to explain the present invention and are not intended to limit the present invention. That is, the embodiments described herein are only some embodiments of the present invention, not all embodiments. Generally, the components of the embodiments of the present invention described and illustrated in the drawings herein may be arranged and designed in various different configurations.

[0044] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention as claimed, but is merely intended to represent selected embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative work are within the scope of protection of the present invention.

[0045] It should be noted that relational terms such as "first" and "second" that may appear are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, terms such as "include", "comprise" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device that includes a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, elements defined by the phrase "including a..." do not exclude processes or methods that include the elements.

[0046] In the description of the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; or internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0047] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "provided with" and "provided with" should be understood in a broad sense. For example, the object "provided with" may be a part of the main body, or may be arranged separately from the main body and connected to the main body. The connection may be detachable or non-detachable. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0048] The present invention is described in further detail below with reference to the examples.

[0049] Specific embodiment 1 of the shield machine air cushion chamber provided by the present invention:

[0050] The shield machine air cushion chamber in this embodiment is assembled in the shield body of the shield machine, and includes a chamber body and a liquid level detection device provided on the top of the chamber body. The liquid level detection device is used to detect the liquid level height of the muddy water in the chamber body. Figures 1 to 3As shown, the liquid level detection device includes a sealing box 1 and a light emitter and an imaging device assembled in the sealing box 1. The imaging device is specifically an industrial camera 18. The liquid level detection device also includes a controller (not shown in the figure). The light emitter and the imaging device are both connected to the controller. There are two light emitters, and the two light emitters are used to emit two parallel beams of light to the liquid surface in the air cushion bin, thereby forming two light spots 23 on the liquid surface. The imaging device is used to obtain an image of the liquid surface in the bin containing the light spots 23 and provide it to the controller. Through the arrangement of the imaging device and the light emitter, real-time height detection of the mud and water liquid level 22 in the air cushion bin of the shield machine and visualization of the internal environment of the bin are realized, which is convenient for the construction and excavation of the shield machine.

[0051] The controller in this embodiment is used to execute a method (control program) for obtaining the height of the muddy water level 22. The method can be summarized and briefly described as follows: Figure 4 and Figure 9 As shown, the image is analyzed to determine the image distance d between the images formed by the two light spots 23 on the photosensitive surface 21 of the imaging device. The height h = f*d0 / d between the imaging device lens and the liquid level in the chamber is calculated. Based on the height h, the height of the muddy water level 22 is calculated. f and d0 are respectively the known focal length of the imaging device lens and the actual distance between the two light spots 23. The actual distance between the two light spots 23 is the horizontal distance between the two light emitters on the bottom plate of the sealed box. In other embodiments, more than two light emitters can be provided, for example, four light emitters are evenly distributed around the imaging device. When measuring the muddy water level, the light spots formed on the muddy water surface by any two of the light emitters are selected for measurement. The specific process of obtaining the height of the muddy water level 22 will be described in detail later.

[0052] The structure of the liquid level detection device in the air cushion chamber of the shield machine in this embodiment is described in detail below:

[0053] like Figure 1 and Figure 2 As shown, the sealing box 1 is a closed rectangular box structure, which includes a top plate 3, a bottom plate 4 and side plates 5 in the four directions of front, back, left and right, which are detachably connected together. Among them, the inner wall end surface of each plate of the sealing box 1 is provided with a sealing groove 2, and each plate is detachably connected by fixing bolts. In this embodiment, the sealing box 1 is made of metal material, which has high strength and can meet the industrial protection level required for shield construction and excavation. Figure 2 As shown, a plurality of connection holes are provided on the upper side of the top plate 3, and connection bolts 20 are passed through the connection holes. The connection bolts 20 are used to penetrate upward into the top of the air cushion bin body, thereby fixing the sealing box 1 on the top of the air cushion bin.

[0054] like Figure 1 and Figure 2As shown, the light emitter and the imaging device are both assembled in the sealed box 1. The imaging device is assembled on the center of the upper side of the bottom plate 4 through the imaging device mounting assembly. The two light emitters are respectively placed on the left and right sides of the imaging device. The two light emitters are also fixed on the upper side of the bottom plate 4. Figure 3 As shown, the base plate 4 has light-transmitting portions corresponding to the imaging device and light emitter. These portions include an opening on the base plate 4 and a protective glass disposed within the opening. These portions enable both the imaging device and the light emitter to illuminate the liquid surface within the air cushion chamber. The light-transmitting portion corresponding to the imaging device includes a first opening on the base plate 4 and a lens protective glass 12 disposed within the first opening. The lower surface of the lens protective glass 12 contacts the exterior of the sealed box 1. The light-transmitting portion corresponding to the emitter includes a second opening on the base plate 4 and a laser protective glass 27 disposed within the second opening. The lower surface of the laser protective glass 27 contacts the exterior of the sealed box 1. Each protective glass serves to seal the base plate opening while maintaining the ability to transmit light through the imaging device and light emitter. A light-filling layer 11 is also disposed on the upper surface of the lens protective glass 12 to supplement illumination for the imaging device.

[0055] like Figure 3 As shown, multiple self-cleaning nozzles 13 are fixed to the lower side of the bottom plate 4 of the sealed box 1 by bolts. The self-cleaning nozzles 13 are arranged around the light-transmitting portion. Two self-cleaning nozzles 13 are symmetrically arranged around the outer periphery of the bottom plate opening of the same light-transmitting portion. The water spray ports of the self-cleaning nozzles 13 are arranged toward the bottom plate opening and below the opening, so as to spray cleaning water toward the protective glass in the bottom plate opening and clear the space in front of the lens so that the imaging device can obtain a clear field of view. Figure 1 and Figure 2 As shown, a water inlet 25 is provided on the rear side plate 5 of the sealing box 1. The water inlet 25 is used to supply water to the self-cleaning nozzle 13 and can also supply water to the imaging device for cleaning.

[0056] like Figure 1 and Figure 2 As shown, the upper end of the imaging device mounting assembly is fixedly connected to the top plate 3 of the sealed box 1, the lower end of the imaging device mounting assembly is connected to the lens protection glass 12, and the light emitter is assembled on the bottom plate 4 via the emitter fixing bracket 17. The light emitter fixing bracket 17 is a bent plate made of metal material, one end of the bent plate is fixedly connected to the bottom plate 4, and the other end of the bent plate is fixedly connected to the light emitter.

[0057] like Figure 1 and Figure 2 As shown, the imaging device mounting assembly includes a protective shell 7 provided outside the imaging device, and also includes a vibration reduction structure connected between the protective shell 7 and the top plate 3. A device fixing frame 6 is provided inside the protective shell 7, and the device fixing frame 6 fixes the imaging device in the protective shell 7. Figure 1As shown, the protective shell 7 is a double-platform structure with upper and lower parts that are interconnected. It is divided into an upper platform 8 and a lower platform 9. Both platforms are cylindrical. The upper platform 8 is used to connect to the top plate 3 of the sealing box 1, and the lower platform 9 is used to connect to the bottom plate 4 of the sealing box 1. The bottom end of the upper platform 8 is provided with an upper platform flange 801, and the top end of the lower platform 9 is provided with a lower platform flange 901. The upper platform flange 801 and the lower platform flange 901 are connected to each other to achieve the interconnection of the aforementioned double-platform structure and form a cylindrical inner cavity inside the cylindrical double platform. The imaging device is assembled in the cylindrical inner cavity formed by the connection of the upper platform 8 and the lower platform 9 through the device fixing frame 6. Among them, the vibration reduction structure includes a support frame 14 and a vibration damper 15 connected to the bottom of the support frame 14. The support frame 14 is a V-shaped support frame. Three support frames 14 are provided outside the protective shell 7. Each support frame 14 is arranged around the upper platform 8. The lower end of the support frame 14 is fixedly connected to the upper platform flange 801 through the vibration damper 15. The upper end of the support frame 14 is fixedly connected to the top plate 3 via bolts, and the vibration damper 15 flexibly supports the support frame 14 on the upper side of the upper platform flange 801, thereby flexibly connecting the protective shell 7 and the top plate 3. In other embodiments, the number of support frames can be increased or decreased according to the connection and support conditions between the protective shell and the top plate to ensure that the protective shell and the top plate are firmly supported.

[0058] like Figure 1 As shown, the lower end of the lower platform 9 is provided with a lens opening, in which a glass baffle 10 is sealed and fixed. The glass baffle 10 corresponds to the first opening, the fill light layer 11 and the lens protection glass 12 in the upper and lower parts. Figure 1 As shown, the glass baffle 10, the fill light layer 11, and the lens protective glass 12 are fixed to the base plate 4 via bolts. The fill light layer 11 is provided between the glass baffle 10 and the lens protective glass 12. The three are stacked and abutted from top to bottom, achieving the fixed assembly of the lower platform 9 on the base plate 4. A sealing ring 26 is also press-fitted between the lens protective glass 12 and the glass baffle 10. The sealing ring 26 includes an annular gasket and a sealing cylinder surrounding the outer periphery of the annular gasket. The annular gasket is sandwiched between the lens protective glass 12 and the glass baffle 10. The sealing cylinder surrounds the outer periphery of the gap between the lens protective glass 12 and the glass baffle 10, and the lower end of the sealing cylinder presses against the base plate 4.

[0059] The vibration damper 15 in this embodiment is a metal-rubber damper, primarily composed of a metal rubber, a cup, a sleeve, a gasket, and screws. During installation, the metal rubber is initially loaded into the cup, forming an interference fit with the cup. When the protective shell 7 vibrates due to the external environment, the vibration causes the upper platform 8 to deflect in various directions, causing the metal wires of the metal rubber to squeeze and slide against each other, thereby suppressing the vibration of the protective shell 7.

[0060] In this embodiment, the imaging device is an industrial camera 18, and the light emitter is a laser 16. Figure 1As shown, a signal transmission interface 19 is also provided on the rear side panel 5 of the sealing box 1, and a camera wiring port 24 is provided on the top of the upper platform 8. The camera wiring port 24 is a wiring interface for the camera's power line, signal line and control line, and the signal transmission interface 19 is a wiring port for the connection line connecting the industrial camera 18 and the laser 16 to the controller.

[0061] like Figures 4 to 10 As shown, the specific process and working principle of the embodiment 1 of the shield machine air cushion chamber for measuring the mud and water level in the air cushion chamber are as follows: Figure 4 As shown, the two lasers 16 and the industrial camera 18 are arranged in parallel and vertically installed above the muddy water level 22 in the bin. The industrial camera 18 is also kept perpendicular to the muddy water level 22 to be measured. The laser emission and adjustment of the laser 16 are controlled by the controller to ensure that the light spot 23 formed by the laser 16 emission is minimized and has the highest brightness. The industrial camera 18 is connected to the controller via Ethernet, so that when the image of the muddy water level 22 is collected, the image is transmitted to the controller, and the controller processes, calculates and displays the image. Figure 5 As shown, the controller includes an image processing module, a visualization module and a liquid level calculation module.

[0062] Laser 16 serves as a light source for emitting laser light toward the muddy water level 22 within the air cushion chamber, forming a light spot 23. This provides a reference feature for image processing and avoids interference from ambient light. Furthermore, the brightness of the light emitted by laser 16 is much higher than natural light. Therefore, even if the ambient light brightness within the air cushion chamber changes, or the air cushion chamber is completely dark, the light spot 23 provided by laser 16 remains highly visible in the image, enabling the present invention to demonstrate strong environmental adaptability. In this method, laser 16 emits a red laser beam, which can form a red light spot 23 on the muddy water level 22 to be detected.

[0063] The industrial camera 18 is used to collect images of the mud and water liquid level 22 in the air cushion bin. The industrial camera 18 has an industrial lens 28, which can realize light beam transformation and image the mud and water liquid level 22 on the photosensitive surface 21 of the photosensitive chip of the industrial camera 18, thereby realizing vision-based liquid level height detection and visualization function inside the air cushion bin.

[0064] The controller obtains the image captured by the industrial camera 18 and performs subsequent processing and calculation steps as follows (S1-S11):

[0065] S1. Adjust the laser aperture and control the laser to generate a laser beam, forming two red spots on the muddy water surface. Use the industrial camera 18 to collect the muddy water surface 22 image in real time and send it to the controller for image processing.

[0066] S2. When the muddy water level changes, the position of the light spot in the muddy water surface image also changes. Based on the installation position of the laser, a region of interest (ROI) can be determined. The position of the light spot always moves within the ROI in the image. The ROI in the muddy water surface image is extracted to obtain an ROI image. This ROI extraction method can reduce the workload of subsequent image processing, greatly increasing image processing efficiency. It also reduces the area of ​​the detection light spot, reducing the probability of error.

[0067] When determining the ROI, it is necessary to ensure that the size of the ROI is appropriate. If the ROI is too large, the improvement in image processing efficiency will not be significant enough, thus losing the meaning of extracting the ROI. If the ROI is too small, it is easy to cause incomplete spot information, resulting in liquid level detection failure.

[0068] like Figure 6 As shown in the figure, each small square represents a pixel in the muddy water surface image. Depending on the installation position of the laser, the two light spots always move left and right in the muddy water surface image. Therefore, using P0 (u0, v0) in the muddy water surface image as the starting point, an image of the region of interest with a width of W and a height of H is intercepted, and then the image of the region of interest is subjected to light spot detection.

[0069] S3, the image of the region of interest is a color image, and the image of the red channel in the image of the region of interest is extracted and processed to improve the accuracy of spot recognition. Figure 7 As shown in the figure, each pixel in the image of the region of interest is composed of the colors of the three channels of blue, green, and red, and arranged in a fixed order. Therefore, the color of the red channel in each pixel is extracted in turn and rearranged in the original order to obtain the red channel image.

[0070] S4. Grayscale the red channel image. The pixel value of each pixel in the red channel image is between 0 and 255. A threshold T is set. Pixels with values ​​below the threshold T are set to 0, and pixels with values ​​above the threshold T are set to 255. This produces a black and white image of the muddy water surface. In the black and white image of the muddy water surface, the light spot area is white, and most other areas are black.

[0071] S5. Perform image opening on the black-and-white image of the muddy and water surface. Image opening is a basic operation method in image processing, including erosion and dilation. Erosion can remove small noise, but it will reduce the spot size. Dilation restores the spot to its original size without reappearing noise, thus removing isolated small spots and burrs from the black-and-white image of the muddy and water surface.

[0072] The formula for the corrosion operation is shown in formula (1). Use template B to traverse the black-and-white image A of the muddy and water surface. If the pixel values ​​of the pixels in the area covered by template B in the black-and-white image A of the muddy and water surface are all 255, then the pixel value of the reference point in the black-and-white image A of the muddy and water surface is set to 255, otherwise it is set to 0.

[0073]

[0074] The formula for the expansion operation is shown in formula (2). Use template B to traverse the black-and-white image A of the muddy and water surface. If the pixel values ​​of the pixels in the area covered by template B in the black-and-white image A are all 0, then the pixel value of the reference point in the black-and-white image A of the muddy and water surface is set to 0, otherwise it is set to 255.

[0075]

[0076] Template B can use a 3×3 or 5×5 square or circle. The specific size is determined by the size of the noise. The larger the noise, the larger the template size used, and the smaller the noise, the smaller the template size used.

[0077] S6. Performing connected region analysis on the black and white image of the muddy water surface after noise removal, segmenting and marking the disconnected regions in the image, wherein the segmented regions have characteristics such as position, size, and area. In this embodiment, the seed filling method is used to perform connected region analysis, and the specific process is as follows:

[0078] S6.1. Traverse the black and white image of the muddy water surface 22 after noise removal. If the pixel value is 255, proceed to step S6.2.

[0079] S6.2. Use the current pixel as a seed and assign it a new label. Then put the positions of all adjacent pixels with a pixel value of 255 into the queue.

[0080] S6.3. Delete the last pixel in the queue, assign it the same label value, and put the positions of all adjacent pixels with a pixel value of 255 into the queue.

[0081] S6.4. Repeat step S6.3 until the queue is empty.

[0082] S6.5. Repeat steps S6.1-S6.4 to continue traversing the black and white image of the muddy and water surface after noise removal until the image traversal is completed.

[0083] Through connected region analysis, different labels can be assigned to different connected regions in the black and white image of the muddy and water surface after noise removal, and then the width, height, area and perimeter information of different connected regions can be statistically calculated.

[0084] S7. Based on the characteristics of the light spot in this embodiment, different connected regions are screened to determine the light spot region. A range of area, width, and height is set, and connected regions within this range are considered candidate regions for the light spot location. Because the light spot is circular, only circular connected regions are considered candidate light spot regions.

[0085] The circularity of each candidate region is calculated using formula (3). The circularity of a circle is 1, and the circularity of a line segment is 0. Therefore, the closer the circularity is to 1, the closer the connected region is to a circle, and the more likely it is a light spot region. On both sides of the center point of the black and white image of the muddy water surface after noise removal, the connected regions with the largest circularity are selected as light spot regions.

[0086]

[0087] Where Roundness is the roundness of the connected region, S is the area of ​​the connected region, and L is the perimeter of the connected region.

[0088] S8. Calculate the coordinates of the center point of the spot area as the location of the spot. The spot area includes multiple pixels. The center of gravity of the spot area is used as the center point of the spot. The coordinates of the center point of the spot are calculated using the following formulas (4) and (5).

[0089]

[0090]

[0091] Where, (u i , v i ) is the coordinate of each pixel in the spot area, the unit is pixel, (u, v) is the coordinate of the center point of the spot, the unit is pixel, and n is the number of pixels in the spot area.

[0092] S9. Calculate the distance between the two light spots based on the center coordinates of the two light spot areas. Figure 8 As shown in the figure, P1 and P2 are the center points of the two light spot areas. The projection distance d between the images formed by the two light spot centers on the photosensitive chip is calculated using the following formula (6):

[0093]

[0094] Where (u1, v1) is the coordinate of the center point P1 of the light spot in the image, (u2, v2) is the coordinate of the center point P2 of the light spot in the image, and px0 is the size of the unit pixel, which is determined by the photosensitive chip and is an inherent parameter of the camera.

[0095] S10, such as Figure 9As shown, the installation distance d0 of the two lasers is measured. Since the industrial camera is parallel to the axes of the two lasers, the distance between the centers of the two light spots on the muddy water surface is equal to the installation distance between the two lasers, which is a fixed value d0. The height from the industrial lens 28 to the muddy water surface is h, and the focal length of the lens is a fixed value f. According to the principle of similar triangles, the height from the industrial lens 28 to the muddy water surface 22 is calculated as h using the following formula (7):

[0096]

[0097] Where h is the height from the industrial lens 28 to the muddy water level 22, f is the focal length of the lens, d is the distance between the images formed by the centers of the two light spots on the photosensitive chip, and d0 is the installation distance between the two lasers.

[0098] S11. According to the camera installation height, subtract the height h from the industrial lens 28 to the muddy and water liquid level 22 measured in real time to obtain the liquid level height measurement value of the muddy and water liquid level 22 in the air cushion tank.

[0099] When there is no mud or water in the air cushion chamber, the distance between the industrial lens 28 and the bottom of the air cushion chamber is measured as the camera installation height.

[0100] In addition, the controller also displays the muddy water level 22 image through a visual interface. When displaying, since the original image captured by the industrial camera 18 has a high resolution, the image needs to be scaled according to the size of the display interface to achieve the best display effect.

[0101] Image scaling is to find the corresponding pixels of the original image based on the target image. Let P(srcX, srcY) be the pixels of the original image, P′(dstX, dstY) be the pixels of the target image, srcW and srcH be the width and height of the original image, and dstW and dstH be the width and height of the target image, i.e., the width and height of the display interface. The corresponding relationship between P and P′ can be expressed by the following formulas (8) and (9):

[0102] srcX=dstX×(srcW / dstW) (8)

[0103] srcY=dstY×(srcH / dstH) (9)

[0104] Usually the calculated P(srcX, srcY) is not an integer and the corresponding pixel cannot be found directly in the original image. Therefore, refer to Figure 10 , the pixel value of point P(srcX, srcY) is obtained by bilinear interpolation.

[0105] First, according to Q 11 The pixel value f(Q 11 ) and Q21 The pixel value f(Q 21 ), calculate the pixel value f(x, y1) of R1(x, y1). The calculation formula is shown in formula (10):

[0106]

[0107] Then, according to Q 12 The pixel value f(Q 12 ) and Q 22 The pixel value f(Q 22 ), calculate the pixel value f(x, y2) of R2(x, y2). The calculation formula is shown in formula (11):

[0108]

[0109] Finally, the pixel value f(x, y) of P(x, y) is calculated based on the pixel value f(x, y1) of R1(x, y1) and the pixel value f(x, y2) of R2(x, y2). The calculation formula is shown in formula (12):

[0110]

[0111] According to formulas (10) to (12), the scaled image can be obtained, and then the scaled image is displayed on the visualization interface.

[0112] The above steps (S1-S11) enable stable, continuous, and accurate measurement of the slurry level within the shield machine's air cushion chamber. This provides data support for parameter adjustments during slurry shield construction, ensuring the stability of the shield machine's tunneling. Furthermore, the air cushion chamber is a pressurized environment, and entering it while under pressure poses a certain risk. The visualization function allows for external observation of the chamber's working conditions, providing a reference for construction personnel to judge the shield machine's tunneling status, avoiding the risk of personnel entering under pressure and improving efficiency and safety.

[0113] In the first embodiment described above, the connections between the emitter mounting bracket 17, the device mounting bracket 6, and the various plates of the sealing box 1, as well as between the support frame 14 and the top plate 3, and between the support frame 14 and the upper platform flange 801, are all detachable connections using threaded members such as bolts or screws. Of course, in other embodiments, these connections may also be welded. Furthermore, the water inlet opening on the side panel of the sealing box can be positioned closer to the bottom plate or closer to the imaging device, as desired.

[0114] In Example 2, which differs from the shield machine air cushion chamber of Example 1, the shape of the protective shell, the connection method of the upper and lower platforms, and the method of fixing the internal imaging device can all be designed differently according to actual circumstances. For example, the protective shell can be a one-piece cylindrical structure with both ends connected to the sealing box. In other embodiments, the structure of the support frame in the vibration reduction structure can also be modified, for example, using spring columns or elastic pads to flexibly connect the protective shell to the sealing box.

[0115] In Embodiment 3, which is different from the shield machine air cushion chamber of Embodiment 1, the self-cleaning nozzles are arranged in a circular or square pattern around the periphery of the bottom plate opening. In other embodiments, the number of self-cleaning nozzles can also be selected to be six, ten, or other different numbers according to specific working conditions.

[0116] In the fourth embodiment of the shield machine air cushion chamber, which is different from the first embodiment, the vibration absorber may also use different types of vibration absorbers such as spring vibration absorbers, rubber vibration absorbers, etc.

[0117] In Example 5, which is different from the shield machine air cushion chamber of Example 1, only one sealing plate of the sealing box is removable, for example, only the top plate or the front side plate of the sealing box is removable. In other embodiments, the connections between the various component plates of the sealing box are welded to increase the sealing performance of the device.

[0118] Specific embodiments of the liquid level detection device provided by the present invention:

[0119] The liquid level detection device in this embodiment is the same as the liquid level detection device in each embodiment of the shield machine air cushion bin mentioned above. The liquid level detection device can be assembled in the shield machine's air cushion bin when in use, so as to observe the internal conditions of the air cushion bin and detect the height of the mud and water level in the air cushion bin. The specific structure of the liquid level detection device will not be described in detail here. However, the liquid level detection device in this embodiment can not only be used for liquid level detection in the shield machine air cushion bin, but also for ranging scenarios in other liquid storage bins such as oil tanks and water tanks. The liquid level detection device has strong applicability. In order to meet the requirements of the assembly scenario, the self-cleaning nozzle and the vibration reduction structure can be appropriately reduced, and only the light emitter, imaging device and controller are retained, thereby reducing the complexity and cost of the system.

[0120] The controller in the liquid level detection device provided by the present invention includes a memory, a processor, and an internal bus. The processor and the memory exchange data and communications with each other via the internal bus. The processor can be a processing device such as a microprocessor (MCU) or a programmable logic device (FPGA). The memory can be any type of memory that stores information using electrical energy, such as RAM and ROM; any type of memory that stores information using magnetic energy, such as a hard disk, floppy disk, magnetic tape, magnetic core memory, bubble memory, or USB flash drive; any type of memory that stores information optically, such as a CD or DVD; and other types of memory, such as quantum memory and graphene memory.

[0121] Finally, it should be noted that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments without inventive effort, or replace some of the technical features therein with equivalents. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A liquid level detection device, comprising a controller and a sealing box, characterized in that: The apparatus further comprises at least two light emitters and an imaging device, both of which are connected to a controller. The light emitters are configured to emit light beams toward the liquid surface in the liquid storage tank, thereby forming two or more light spots on the liquid surface. The imaging device is configured to capture an image of the liquid surface in the tank, including the light spots, and provide the image to the controller. The sealed box is a closed box, and the imaging device and the light emitters are assembled in the sealed box. The at least two light emitters are mounted on either side of the imaging device. The sealed box is configured to be fixedly connected to the top of the liquid storage tank so that the imaging device and the light emitters are located at the top of the liquid storage tank. The bottom plate of the sealed box has light-transmitting portions corresponding to the imaging device and the light emitters. A protective shell and a vibration reduction structure are provided in the sealed box. The imaging device is fixedly assembled in the protective shell. The protective shell includes an upper platform and a lower platform fixedly connected to each other. The vibration reduction structure includes a support frame and a vibration damper. The upper end of the support frame is fixedly connected to the top of the sealed box, and the lower end of the support frame is connected to the upper platform of the protective shell through the vibration damper. The lower platform of the protective shell is fixedly assembled on the bottom plate, and the light emitter is fixed on the bottom plate. The controller is used to execute the following method: analyzing the image to obtain the image distance d between the images formed by the two light spots on the photosensitive surface of the imaging device, calculating the height h = f*d0 / d between the imaging device lens and the liquid level in the chamber, and calculating the height of the liquid level in the chamber based on the height h, where f and d0 are respectively the known focal length of the imaging device lens and the actual distance between the two light spots, and the actual distance between the two light spots is the horizontal distance between the two light emitters on the bottom plate of the sealed box.

2. The liquid level detection device according to claim 1, characterized in that: A lens opening is provided at the lower end of the lower platform (9), a glass baffle (10) is fixed in the lens opening, a first opening corresponding to the lower platform (9) is provided on the bottom plate (4), a lens protection glass (12) is fixed in the first opening to form the light-transmitting portion corresponding to the imaging device, the lens protection glass (12) is in contact with the outside of the sealing box (1), and the lens protection glass (12) is fixedly connected to the glass baffle (10), thereby realizing the fixed assembly of the lower platform (9) on the bottom plate (4).

3. The liquid level detection device according to claim 2, characterized in that: A sealing ring (26) is pressed between the lens protective glass (12) and the glass baffle (10), and the sealing ring (26) includes an annular gasket and a sealing cylinder surrounding the outer periphery of the annular gasket. The annular gasket is clamped between the lens protective glass (12) and the glass baffle (10), and the sealing cylinder surrounds the outer periphery of the fitting gap between the lens protective glass (12) and the glass baffle (10), and the lower end of the sealing cylinder is pressed against the bottom plate (4).

4. The liquid level detection device according to claim 2, characterized in that: A light-filling layer (11) is provided on the upper surface of the lens protection glass (12); the glass baffle (10), the light-filling layer (11) and the lens protection glass (12) are fixed to the bottom plate (4) via bolt connection.

5. The liquid level detection device according to any one of claims 1 to 4, characterized in that: The bottom end of the upper platform (8) is provided with an upper platform flange (801), the top end of the lower platform (9) is provided with a lower platform flange (901), the upper platform (8) and the lower platform (9) are flange-connected, and the shock absorber (15) is fixed on the upper platform flange (801).

6. The liquid level detection device according to any one of claims 1 to 4, characterized in that: A self-cleaning nozzle (13) is provided on the outer surface of the bottom plate (4) of the sealing box (1). The self-cleaning nozzle (13) is arranged beside the light-transmitting portion, and the water spray port of the self-cleaning nozzle (13) is arranged toward the light-transmitting portion.

7. The liquid level detection device according to any one of claims 1 to 4, characterized in that: A second opening corresponding to the light emitter is provided on the bottom plate (4), and a laser protection glass (27) is provided in the second opening to form the light-transmitting portion corresponding to the light emitter. The laser protection glass (27) is in contact with the outside of the sealing box (1).

8. The liquid level detection device according to any one of claims 1 to 4, characterized in that: The sealed box (1) further comprises a top plate (3) and a side plate (5) detachably connected between the top plate (3) and the bottom plate (4); the side plate (5) is provided with a signal transmission interface (19); the signal transmission interface (19) is used for connecting transmission signal lines of the light emitter and the imaging device to and from the sealed box (1).

9. A shield machine air cushion chamber, comprising a chamber body constituting a liquid storage chamber, characterized in that: It also includes a liquid level detection device installed on the top of the interior of the bin body, the liquid level detection device is the liquid level detection device described in any one of claims 1-8, and the liquid level detection device is used to obtain the liquid level height of the mud and water liquid level (22) in the shield machine air cushion bin.

Images