A liquid level detection device based on millimeter wave radar with low dielectric constant

Abstract

The present invention relates to a millimeter-wave radar-based liquid level detection device with a low dielectric constant, which includes a housing structure, a radar wave transceiver structure arranged at the inner top of the housing structure, and a radar wave reflection structure arranged at the bottom end of the housing structure. The detection device is provided with a float on the liquid surface, and a reflector is arranged at the top of the float to form a strong and easily distinguishable radar reflection wave, facilitating the detection of the liquid level height. A cylindrical outer shell with a low dielectric constant is provided to limit the float. The cylindrical outer shell with a low dielectric constant can transmit radar waves to prevent reflection interference. The present invention is provided with a resistance structure to delay the upward floating amplitude of the float when it approaches the radar blind area, avoiding entering the radar blind area. Due to the high accuracy of radar waves, the accuracy of the liquid level detection device of the present invention is greatly improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of liquid level detection devices, and particularly relates to a low dielectric constant liquid level detection device based on a millimeter wave radar. Background Art

[0002] Liquid level sensors can be divided into contact and non-contact sensors. Representative contact sensors include float sensors and static pressure sensors. Representative non-contact sensors are ultrasonic liquid level sensors. The disadvantages of the above liquid level sensors are low accuracy, and the lower the liquid level, the less accurate the measurement. The detection accuracy of millimeter wave radar is high, which can be accurate to the millimeter level. Although the application of millimeter wave radar to liquid level sensors can greatly improve the accuracy, there are the following difficulties: substances with low dielectric constant have small reflection of radar waves, and the recovered signals are messy and difficult to distinguish; millimeter wave radar has a detection blind area. If the liquid level is close to the transceiver of the millimeter wave radar, the reflected wave is more messy and difficult to distinguish. When installing a millimeter wave radar in a liquid-filled tank, a large space needs to be reserved. Summary of the Invention

[0003] The purpose of the present invention is to provide a low dielectric constant liquid level detection device based on a millimeter wave radar to solve the above problems.

[0004] The present invention achieves the above purpose through the following technical solutions:

[0005] A low dielectric constant liquid level detection device based on a millimeter wave radar includes a housing structure, a radar wave transceiver structure arranged at the top end inside the housing structure, and a radar wave reflection structure arranged at the bottom end of the housing structure. Among them, the housing structure includes a cylindrical outer shell made of a low dielectric constant material and side holes opened on the side wall at the top end of the cylindrical outer shell. The radar wave reflection structure includes a float slidably arranged inside the cylindrical outer shell and a reflection sheet arranged on the top surface of the float.

[0006] As a further optimized solution of the present invention, the radar wave transceiver structure includes a transceiver and an antenna cover, and a detachable top cover for protecting the transceiver is arranged at the top opening of the cylindrical outer shell.

[0007] As a further optimized solution of the present invention, at least two outwardly extending side grooves are arranged on the side wall at the bottom end of the cylindrical outer shell, and a resistance structure is arranged in the side grooves. The height of the float in the lower half of the cylindrical outer shell fluctuates linearly with the liquid level. The resistance structure is used to reduce the upward floating amplitude of the float when the float moves to the upper half of the cylindrical outer shell. By setting the resistance structure, when the float is about to approach the radar wave transceiver structure, its upward floating amplitude is delayed. At this time, the float floats relying on the liquid level pressure on its lower surface. The higher the liquid level, the higher the static pressure at the bottom end of the float, which promotes the float to float, while the resistance structure reduces this upward floating amplitude to prevent the float from entering the blind area of the radar wave.

[0008] As a further optimized solution of the present invention, the resistance structure includes a sliding cylinder disposed inside the side groove. A sliding rod is slidably connected inside the sliding cylinder, and a tensile elastic member is connected between the sliding cylinder and the sliding rod. A hook rod for hooking the float is disposed at the top end of the sliding rod. An upper arc shoulder is disposed on the outer periphery of the upper end of the float, and a lower arc bottom is disposed on the outer periphery of the lower end of the float. A hook plate corresponding to the hook rod is disposed at the bottom end of the lower arc bottom. This structural setting enables the float to slide without being affected in the lower half of the cylindrical outer shell and can be docked with the resistance structure when sliding in the upper half of the cylindrical outer shell.

[0009] As a further optimized solution of the present invention, a hinge groove for hinging with the hook rod is disposed at the top end of the sliding rod. An angular limiting plate for limiting the hook rod is disposed at one end of the hinge groove. A torsion spring for pushing the hook rod towards the angular limiting plate is disposed on the hinge shaft at the hinged portion of the sliding rod and the hook rod. This structure enables the hook rod to maintain an appropriate angle, facilitating docking with the hook plate at the bottom end of the float.

[0010] As a further optimized solution of the present invention, the sliding cylinder is foldably stored in the side groove. At least two hinge rods that are parallel to each other and hinged to the sliding cylinder are disposed in the side groove. A positioning rod for limiting the rotation angle of the hinge rod is disposed on the side wall of the side groove, making the sliding cylinder and the tensile elastic member keep vertical, with balanced force. The deformation of the tensile elastic member and the tensile force maintain a linear change, which is beneficial to accuracy.

[0011] As a further optimized solution of the present invention, a sealing strip is disposed on the side surface of the float. After the float is docked with the resistance structure, when the liquid level rises, a static pressure is formed at the bottom end of the float. To maintain the static pressure, the sealing strip is provided to prevent leakage.

[0012] As a further optimized solution of the present invention, the cylindrical outer shell and the resistance structure are made of acrylic plates. The acrylic plates have a low dielectric constant and a small reflection amount of radar waves, which can reduce the clutter degree of the echo.

[0013] The beneficial effects of the present invention are as follows:

[0014] 1) In the present invention, a float is provided on the liquid surface, and a reflection sheet is disposed at the top end of the float to form a strong and easily distinguishable radar reflection wave, facilitating the detection of the liquid level height. A cylindrical outer shell with a low dielectric constant is provided to limit the float. The cylindrical outer shell with a low dielectric constant can transmit radar waves, preventing reflection interference.

[0015] 2) In the present invention, by providing a resistance structure, the upward floating amplitude of the float is delayed when approaching the radar wave blind area, avoiding entering the radar blind area. Thanks to the high precision of radar waves, the accuracy of the liquid level detection device of the present invention is greatly improved. Description of the Drawings

[0016] Figure 1 is the overall structural schematic diagram of the present invention;

[0017] Figure 2 is the schematic diagram of the resistance structure storage of the present invention;

[0018] Figure 3 is the sectional view of the sliding cylinder structure of the present invention;

[0019] Figure 4 is of the present invention Figure 1 sectional view taken along line A-A;

[0020] Figure 5 is of the present invention Figure 1 enlarged view of part B structure;

[0021] Figure 6 is of the present invention Figure 3 enlarged view of part C structure;

[0022] In the figure: 1. housing structure; 11. cylindrical outer shell; 12. top cover; 13. side hole; 14. side groove; 2. radar wave transceiver structure; 21. transceiver; 22. radome; 3. radar wave reflection structure; 31. float; 32. reflection sheet; 33. upper arc shoulder; 34. lower arc bottom; 35. hook plate; 36. sealing strip; 4. resistance structure; 41. hinge rod; 42. sliding cylinder; 43. sliding rod; 44. tension elastic member; 45. hinge groove; 46. hook rod; 47. torsion spring; 48. angle limiting plate; 49. positioning rod. Detailed implementation manners

[0023] The following further describes the present application in detail with reference to the accompanying drawings. It is necessary to point out here that the following specific implementation manners are only used to further illustrate the present application and cannot be understood as limiting the protection scope of the present application. Those skilled in the art can make some non-essential improvements and adjustments to the present application according to the above application content.

[0024] Embodiment 1

[0025] As Figures 1-6 shown, a millimeter-wave radar-based low-dielectric-constant liquid level detection device includes a housing structure 1, a radar wave transceiver structure 2 disposed at the top end inside the housing structure 1, and a radar wave reflection structure 3 disposed at the bottom end of the housing structure 1. Among them, the housing structure 1 includes a cylindrical outer shell 11 with a low dielectric constant and a side hole 13 opened on the side wall at the top end of the cylindrical outer shell 11, and the radar wave reflection structure 3 includes a float 31 slidably disposed inside the cylindrical outer shell 11 and a reflection sheet 32 disposed on the top surface of the float 31.

[0026] The radar wave has a small reflection amount in the liquid level with low dielectric constant and is difficult to distinguish. Therefore, a float 31 is set on the liquid surface, and a reflector 32 is set on the top of the float 31 to form a strong and easily distinguishable radar reflection wave, which is convenient for detecting the liquid level height. A cylindrical shell 11 with a low dielectric constant is set to limit the float 31. The cylindrical shell 11 with a low dielectric constant can transmit radar waves to prevent reflection interference.

[0027] The radar wave transceiver structure 2 includes a transceiver 21 and an antenna cover 22. A detachable top cover 12 for protecting the transceiver 21 is provided at the top opening of the cylindrical shell 11. The antenna cover 22 can be used to organize radar waves, so that the reflector 32 can generate more echoes for easy identification.

[0028] It is found during use that radar wave detection has a blind spot, and it is difficult to detect materials very close to the radar wave transceiver port. This is because the reflection of radar waves is disorderly and the reflected radar waves are relatively concentrated, making it difficult to determine whether the radar waves are reflected by the reflector 32. Therefore, it is necessary to reserve sufficient detection space during installation, or reduce the loading rate of the liquid box / tank. In order to solve this problem, the present invention provides a resistance structure 4.

[0029] The bottom side wall of the cylindrical shell 11 is provided with at least two side grooves 14 extending outward, and a resistance structure 4 is provided in the side groove 14. When the float 31 is in the lower half of the cylindrical shell 11, the liquid level is at a lowered level, and the height of the float 31 fluctuates linearly with the liquid level. As the liquid level rises, the float 31 moves to the upper half of the cylindrical shell 11, and gradually approaches the transceiver 21. The resistance structure 4 and the float 31 are hooked with each other, reducing the rising amplitude of the float 31. At this time, the buoyancy of the rising float 31 comes from the static pressure at the bottom end of the float 31. The higher the liquid level, the higher the static pressure. The static pressure is damped by the tension elastic member 44, so that the height of the float 31 still changes with the rise of the liquid level. The rising height of the float 31 corresponds to the actual height of the liquid level. The actual liquid level height can be obtained by measuring the height of the float 31 and converting it. In order to improve the stability of the static pressure, a sealing strip 36 is provided on the side surface of the float 31.

[0030] The resistance structure 4 specifically includes a slide cylinder 42 arranged inside the side groove 14, and a slide rod 43 is slidably connected inside the slide cylinder 42, and a tension elastic member 44 is connected between the slide cylinder 42 and the slide rod 43, a hook rod 46 for hooking the float 31 is arranged at the top of the slide rod 43, and a hook plate 35 corresponding to the hook rod 46 is arranged at the bottom end of the float 31, and a hinge groove 45 for hinged connection with the hook rod 46 is arranged at the top of the slide rod 43, and an angle limiting plate 48 for limiting the hook rod 46 is arranged at one end of the hinge groove 45, and a torsion spring 47 for pushing the hook rod 46 toward the angle limiting plate 48 is arranged on the hinge axis at the hinge between the slide rod 43 and the hook rod 46. This structure enables the hook rod 46 to maintain a suitable angle, which is convenient for docking with the hook plate 35 at the bottom end of the float 31.

[0031] To prevent the float 31 from being affected by the hook rod 46 when moving up and down, an upper arc shoulder 33 is provided on the outer periphery of the upper end of the float 31, and a lower arc bottom 34 is provided on the outer periphery of the lower end of the float 31.

[0032] The sliding cylinder 42 is foldably accommodated in the side groove 14. At least two hinge rods 41 that are parallel to each other and hinged to the sliding cylinder 42 are provided in the side groove 14. A positioning rod 49 for limiting the rotation angle of the hinge rod 41 is provided on the side wall of the side groove 14. Through this setting, the hook rod 46 slides the cylinder into the cylindrical housing 11 from the side groove 14 after being stressed. The sliding cylinder 42 and the tension elastic member 44 are vertically stressed, and the deformation of the tension elastic member 44 changes linearly with the tension, which is beneficial to the accuracy.

[0033] The materials of the cylindrical housing 11 and the resistance structure 4 are acrylic plates. The acrylic plate has a low dielectric constant and a small reflection amount of radar waves, which can reduce the clutter degree of the echo. In fact, in the housing structure 1 and the resistance structure 4, except for the elastic element, other structures need to be made of materials with low dielectric constants.

[0034] It should be noted that the tension elastic member 44 is an elastic member with a linear change. It can be a tension spring, but the tension spring is made of metal and will reflect a small amount of radar waves, which has a certain interference to the recovery and analysis of radar waves. It can also be other elastic members with a linear change, but the linearity of the change of tension and deformation is not as good as that of the tension spring.

[0035] The specific implementation mode is as follows: When the liquid tank / can is at a low liquid level, the float 31 is at the bottom end of the cylindrical housing 11. When the float 31 rises with the liquid level, first, the hook rod 46 is pushed back into the side groove 14 through the upper arc shoulder 33. When the hook plate 35 at the bottom end of the float 31 contacts the hook rod 46, the hook rod 46 is driven to rise, and the sliding cylinder 42 extends out of the side groove 14 under the pull. When the liquid level continues to rise, the sealing strip 36 on the side surface of the float 31 makes the float 31 and the cylindrical housing 11 above it form an equivalent "float cylinder". As the static pressure at the bottom end of the float 31 becomes larger and larger, the float 31 moves upward against the resistance of the tension elastic member 44, and the upward movement amplitude decreases, so that the float 31 will not approach the transceiver 21 as the liquid level rises, avoiding entering the blind area of the radar wave.

[0036] The above-described embodiments only represent several implementation modes of the present invention. The description is relatively specific and detailed, but it cannot be understood as a limitation to the scope of the patent of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several deformations and improvements can still be made, and these all belong to the protection scope of the present invention.

Claims

1. A liquid level detection device based on millimeter wave radar with low dielectric constant, characterized in that: The invention comprises a shell structure (1), a radar wave transceiver structure (2) arranged at the top end of the shell structure (1), and a radar wave reflection structure (3) arranged at the bottom end of the shell structure (1), wherein the shell structure (1) comprises a cylindrical shell (11) with a low dielectric constant, a side hole (13) opened on the side wall of the top end of the cylindrical shell (11), and the radar wave reflection structure (3) comprises a float (31) slidably arranged inside the cylindrical shell (11) and a reflection sheet (32) arranged on the top end surface of the float (31); The bottom side wall of the cylindrical shell (11) is provided with at least two side grooves (14) extending outwards, and a resistance structure (4) is provided in the side groove (14). The height of the float (31) in the lower half of the cylindrical shell (11) fluctuates linearly with the liquid level, and the resistance structure (4) is used to reduce the floating amplitude of the float (31) when the float (31) moves to the upper half of the cylindrical shell (11); The resistance structure (4) comprises a slide cylinder (42) arranged inside the side groove (14), the slide cylinder (42) is slidably connected to a slide rod (43) inside, and a tension elastic member (44) is connected between the slide cylinder (42) and the slide rod (43), a hook rod (46) for hooking the float (31) is arranged at the top of the slide rod (43), an upper arc shoulder (33) is arranged on the outer periphery of the upper end of the float (31), a lower arc bottom (34) is arranged on the outer periphery of the lower end of the float (31), and a hook plate (35) corresponding to the hook rod (46) is arranged at the bottom end of the lower arc bottom (34).

2. The liquid level detection device based on millimeter wave radar with low dielectric constant according to claim 1, characterized in that: The radar wave transceiver structure (2) comprises a transceiver (21) and a radome (22), and a detachable top cover (12) for protecting the transceiver (21) is provided at the top opening of the cylindrical housing (11).

3. The liquid level detection device based on millimeter wave radar with low dielectric constant according to claim 1, characterized in that: A hinge groove (45) for hinged connection with the hook rod (46) is arranged at the top end of the slide rod (43); an angle limit plate (48) for limiting the position of the hook rod (46) is arranged at one end of the hinge groove (45); and a torsion spring (47) for pushing the hook rod (46) toward the angle limit plate (48) is arranged on the hinge shaft at the hinged joint between the slide rod (43) and the hook rod (46).

4. The millimeter-wave radar-based low-dielectric constant liquid level detection device according to claim 1, characterized in that: The slide cylinder (42) is foldably stored in the side groove (14), and at least two hinged rods (41) parallel to each other and hinged to the slide cylinder (42) are provided in the side groove (14), and a positioning rod (49) for limiting the rotation angle of the hinged rod (41) is provided on the side wall of the side groove (14).

5. The liquid level detection device with low dielectric constant based on millimeter wave radar according to claim 1, characterized in that: A sealing strip (36) is provided on the side surface of the float (31).

6. The liquid level detection device based on millimeter wave radar with low dielectric constant according to claim 1, characterized in that: The cylindrical shell (11) and the resistance structure (4) are made of acrylic board.

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