Single metal tube capacitive liquid level sensor

Abstract

The application discloses a single metal tube capacitive liquid level sensor, which comprises a mounting disc and an electric connector arranged on the top of the mounting disc, the bottom of the mounting disc is provided with a hollow conductive single tube, the inside of the hollow conductive single tube is coaxially provided with a hollow cylinder, the inside of the hollow cylinder is provided with a magnetic floating part which floats along with the inclination angle of the hollow conductive single tube, and the outside of the hollow cylinder is provided with an inductance part which is inductively connected with the magnetic floating part; the outside of the hollow conductive single tube is sealedly wrapped with an insulating heat shrink tube, the outside of the insulating heat shrink tube is slidably sleeved with a first electrode, and the first electrode, the hollow conductive single tube and the inductance part are connected with the electric connector through cables respectively; the single tube structure is adopted to detect the liquid level, and the inclination angle of the liquid container can be detected simultaneously.

Description

Technical Field

[0001] This invention belongs to the technical field of liquid level detection and relates to a single metal tube capacitive liquid level sensor. Background Technology

[0002] Liquid level measuring devices are widely used in aircraft, ships, and other applications, primarily for measuring oil and water levels. They are crucial for predicting transport distances and rationally scheduling resupply. Liquid level measuring devices employ various measurement principles and methods, with capacitive sensors, ultrasonic sensors, and pressure sensors being the mainstream approaches. A capacitive sensor consists of two insulated coaxial aluminum tubes forming a cylindrical capacitor, with each tube constituting one of the capacitor's electrodes. When an input signal is applied to the capacitor, an electric field is generated, thus capturing the capacitance value. Different liquid levels within the capacitor result in different output capacitance values. This sensor requires insulation between the two aluminum tubes, making it suitable for measuring the level of non-conductive liquids. However, it is unsuitable for measuring conductive liquids such as water. Furthermore, existing bimetallic tube capacitive liquid level sensors are relatively heavy and bulky due to the need for two metal tubes. Additionally, existing capacitive liquid level sensors cannot detect the tilt angle of liquid containers, exhibiting functional limitations.

[0003] Therefore, in view of the above-mentioned defects of existing bimetallic tube capacitive liquid level sensors, the present invention discloses a single metal tube capacitive liquid level sensor. Summary of the Invention

[0004] The purpose of this invention is to provide a single-tube capacitive liquid level sensor that uses a single-tube structure to detect the liquid level and can also detect the tilt angle of the liquid container.

[0005] This invention is achieved through the following technical solution:

[0006] A single-metal tube capacitive liquid level sensor includes a mounting plate and an electrical connector disposed on the top of the mounting plate. A hollow conductive tube is disposed at the bottom of the mounting plate. A hollow cylinder is coaxially disposed inside the hollow conductive tube. A magnetic levitation part is disposed inside the hollow cylinder, which floats with the tilt angle of the hollow conductive tube. An inductor part that interacts with the magnetic levitation part is disposed outside the hollow cylinder. An insulating heat-shrink tubing is sealed and wrapped around the hollow conductive tube. A first electrode is slidably sleeved on the outside of the insulating heat-shrink tubing. The first electrode, the hollow conductive tube, and the inductor part are respectively connected to the electrical connector via cables.

[0007] This invention is used to detect the liquid level and tilt angle of a conductive liquid. A hollow conductive tube and the conductive liquid being measured are the two poles of a capacitor. When the liquid level changes, the dielectric constant between the conductive liquid and the hollow conductive tube changes, thus changing the capacitance value of the capacitor structure formed between them. An electrical connector connects to an external detection device, which reads the capacitance value in real time and calculates the liquid level height. The method of calculating the liquid level height using capacitance value is existing technology and not an improvement of this invention; therefore, it will not be elaborated upon here.

[0008] When the conductive liquid is relatively still, the relative positions between the magnetic levitation section and the inductor section remain unchanged, and the inductance of the inductor section does not change. When the container of the conductive liquid is tilted, the magnetic levitation section inside the hollow cylinder floats along with the tilt of the hollow conductive tube. Due to the mutual inductance between the magnetic levitation section and the inductor, the inductance in the inductor section changes with the tilt angle of the hollow conductive tube. The method for calculating the change in inductance with the tilt angle is prior art and not an improvement of this invention, and will not be elaborated here.

[0009] To better realize the present invention, the hollow conductive single tube further includes a first conductive half tube and a second conductive half tube that are spliced ​​together, and an insulating element is provided between the splicing surfaces of the first conductive half tube and the second conductive half tube.

[0010] To better realize the present invention, the tops of the first conductive half tube and the second conductive half tube are respectively fastened with end caps, and the end caps are connected to the electrical connectors via cables.

[0011] To better realize the present invention, the inductor further includes a floating bushing and an inductor coil. The floating bushing is slidably sleeved on the outside of the hollow cylinder. A winding groove is provided on the outer side of the floating bushing. An inductor coil is wound in the winding groove. The inductor coil is connected to an electrical connector through a cable.

[0012] To better realize the present invention, the outer side of the inductor coil is further covered with an insulating sleeve.

[0013] To better realize the present invention, the hollow cylinder is further provided with a cavity inside, the cavity is filled with floating oil, and a magnetic levitation part is suspended in the floating oil.

[0014] To better realize the present invention, the magnetic levitation part further includes a magnetic float or a glass capsule filled with magnetic fluid.

[0015] To better realize the present invention, a floating disk is further slidably disposed on the outside of the insulating heat shrink tubing, and a first electrode is disposed at the bottom of the floating disk.

[0016] To better realize the present invention, the floating disk further includes an inner disk, an outer disk, and floating balls. The inner disk is slidably fitted on the outside of the insulating heat shrink tubing, the outer disk is fitted on the outside of the inner disk, and a number of floating balls are rolled between the outer disk and the inner disk.

[0017] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0018] (1) This invention is for conductive liquids. It only requires a hollow conductive tube to form a capacitor structure with the conductive liquid to realize liquid level measurement, which greatly reduces the weight and volume of the liquid level sensor.

[0019] (2) By setting up a magnetic levitation part and an inductor part, when the liquid container is tilted, the inductance of the inductor part changes due to the floating of the magnetic levitation part, and the tilt angle of the container is calculated so as to monitor the attitude of the liquid container. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of a single-metal tube capacitive liquid level sensor.

[0021] Figure 2 for Figure 1 Sectional view along axis AA;

[0022] Figure 3 This is a schematic diagram of the inductor section;

[0023] Figure 4 This is a schematic diagram of the floating disk structure.

[0024] Wherein: 1-Mounting plate; 2-Electrical connector; 3-Hollow conductive single tube; 4-Hollow cylinder; 5-Magnetic levitation part; 6-Inductor part; 7-Insulating heat shrink tubing; 8-Floating plate; 31-First conductive half tube; 32-Second conductive half tube; 33-Insulation; 34-End cap; 61-Floating bushing; 62-Inductor coil; 63-Insulating sleeve; 81-Inner plate; 82-Outer plate; 83-Floating ball; 100-First electrode. Detailed Implementation

[0025] The following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0026] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, unless otherwise expressly indicated by the invention, the singular form is intended to include the plural form as well. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0027] For ease of description, the words "up," "down," "left," and "right" appearing in this invention only indicate that they are consistent with the up, down, left, and right directions of the accompanying drawings themselves, and do not limit the structure. They are merely for the purpose of facilitating the description of this invention and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0028] Terminology Explanation: The terms "installation," "connection," "linking," and "fixing" in this invention should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal connection of two components or the interaction relationship between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0029] Example 1:

[0030] This embodiment provides a single-metal tube capacitive liquid level sensor, such as... Figure 1 and Figure 2 As shown, the device includes a mounting plate 1 and an electrical connector 2 located on top of the mounting plate 1. A hollow conductive tube 3 is located at the bottom of the mounting plate 1. A hollow cylinder 4 is coaxially arranged inside the hollow conductive tube 3. A magnetic levitation part 5 is arranged inside the hollow cylinder 4, which floats with the tilt angle of the hollow conductive tube 3. An inductor part 6 that interacts with the magnetic levitation part 5 is arranged outside the hollow cylinder 4. An insulating heat shrink tubing 7 is sealed and wrapped around the hollow conductive tube 1. A first electrode 100 is slidably sleeved on the outside of the insulating heat shrink tubing 7. The first electrode 100, the hollow conductive tube 3, and the inductor part 6 are connected to the electrical connector 2 via cables.

[0031] The hollow conductive tube 1 is externally sealed with an insulating heat-shrink tubing 7 to form a sealed insulating structure on the outside of the hollow conductive tube 1, preventing direct contact between the hollow conductive tube 1 and the conductive liquid. A first motor 100 is slidably mounted on the outside of the insulating heat-shrink tubing 7. The first electrode 100 floats with the liquid level, ensuring that the first motor 100 is always in contact with the conductive liquid. In this case, the conductive liquid can be considered as one electrode, and the hollow conductive tube 1 as the other electrode. When the liquid level changes, the dielectric constant between the conductive liquid and the hollow conductive tube 1 changes, thereby changing the capacitance between them. The electrical connector 2 is connected to an external detection circuit or detection device to detect the change in capacitance, and the liquid level can be calculated from the change in capacitance.

[0032] Meanwhile, when the conductive liquid container tilts, that is, when the hollow conductive tube 1 tilts, the magnetic levitation part 5 inside the hollow cylinder 4 floats up and down along with the tilt of the hollow conductive tube 1, which causes the inductance in the inductor part 6 to change. The tilt angle of the hollow conductive tube 1, that is, the tilt angle of the conductive liquid container, is calculated by the change in inductance value.

[0033] Example 2:

[0034] A single-metal tube capacitive liquid level sensor, improved based on Embodiment 1, such as... Figure 2 As shown, the hollow conductive single tube 3 includes a first conductive half tube 31 and a second conductive half tube 32 that are spliced ​​together, and an insulating element 33 is provided between the splicing surfaces of the first conductive half tube 31 and the second conductive half tube 32.

[0035] The first conductive half-tube 31 forms a first set of capacitors with the conductive liquid, and the second conductive half-tube 32 forms a second set of capacitors with the conductive liquid. Both sets of capacitors are connected to the electrical connector 2 via cables. The capacitance values ​​of the two sets of capacitors are obtained through a capacitance detection circuit or detection device, forming a redundant backup structure. Even if one set of capacitors fails, the liquid level can still be detected through the other set of capacitors, thus improving the reliability of the liquid level sensor.

[0036] Furthermore, end caps 34 are respectively fastened to the top of the first conductive half tube 31 and the second conductive half tube 32, and the end caps 34 are connected to the electrical connector 2 via cables.

[0037] The other parts of this embodiment are the same as those in Embodiment 1, so they will not be described again.

[0038] Example 3:

[0039] A single-metal tube capacitive liquid level sensor, improved based on Embodiment 1 or 2, such as... Figure 3As shown, the inductor 6 includes a floating bushing 61 and an inductor coil 62. The floating bushing 61 is slidably sleeved on the outside of the hollow cylinder 4. A winding groove is provided on the outer surface of the floating bushing 61, and the inductor coil 62 is wound in the winding groove. The inductor coil 62 is connected to the electrical connector 2 through a cable, and the outer side of the inductor coil 62 is covered with an insulating sleeve 63.

[0040] By sliding the floating bushing 61, the installation position of the inductor coil 62 outside the hollow cylinder 4 can be adjusted to adapt to different detection environments. An insulating layer 63 is provided on the outside of the inductor coil 62 to ensure the insulation between the inductor coil 62 and the hollow conductive tube 1.

[0041] The other parts of this embodiment are the same as those in Embodiment 1 or 2, so they will not be described again.

[0042] Example 4:

[0043] A single-metal tube capacitive liquid level sensor, improved based on any one of embodiments 1-3, such as... Figure 1 As shown, the hollow cylinder 4 has an internal cavity filled with floating oil, and a magnetic levitation part 5 is suspended in the floating oil. The magnetic levitation part 5 includes a magnetic float or a glass capsule filled with magnetic liquid.

[0044] When the hollow conductive tube 1 tilts, the magnetic float 5 in the cavity floats up and down, and the inductance in the inductor 6 changes at this time.

[0045] The other parts of this embodiment are the same as those in Embodiment 4, so they will not be described again.

[0046] Example 5:

[0047] A single-metal tube capacitive liquid level sensor, improved based on any one of embodiments 1-4, such as... Figure 4 As shown, a floating disk 8 is slidably disposed on the outside of the insulating heat shrink tubing 7, and a first electrode 100 is disposed at the bottom of the floating disk 8. The floating disk 8 floats with the liquid level, ensuring that the first electrode 100 at its bottom is always in contact with the conductive liquid.

[0048] Furthermore, the floating disk 8 includes an inner disk 81, an outer disk 82, and floating balls 83. The inner disk 81 is slidably fitted onto the outside of the insulating heat shrink tubing 7, the outer disk 82 is fitted onto the outside of the inner disk 81, and a plurality of floating balls 83 are rolled between the outer disk 82 and the inner disk 81.

[0049] Several arc-shaped grooves are provided on the outer side of the inner disk 81, and several floating balls 83 are rolled in the arc-shaped grooves. The inner wall of the outer disk 82 is rolled in connection with the floating balls 83, thereby forming a floating structure, which allows the outer disk 82 to float more flexibly with changes in liquid level. A first electrode 100 is provided at the bottom of the outer disk 82 to ensure that the first electrode is in contact with the conductive liquid.

[0050] The other parts of this embodiment are the same as any one of embodiments 1-4, so they will not be described again.

[0051] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention in any way. Any simple modifications or equivalent changes made to the above embodiments based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A single metal tube capacitive liquid level sensor comprising a mounting plate (1) and an electrical connector (2) provided on top of the mounting plate (1), characterized in that, The bottom of the installation disc (1) is provided with a hollow conductive single pipe (3), the inside of the hollow conductive single pipe (3) is coaxially provided with a hollow cylinder (4), the inside of the hollow cylinder (4) is provided with a magnetic floating part (5) floating along with the inclination angle of the hollow conductive single pipe (3), the outside of the hollow cylinder (4) is provided with an inductance part (6) inductively interacting with the magnetic floating part (5); the outside of the hollow conductive single pipe (3) is sealedly wrapped with an insulating heat shrink tube (7), the outside of the insulating heat shrink tube (7) is slidingly sleeved with a first electrode (100), the first electrode (100), the hollow conductive single pipe (3) and the inductance part (6) are respectively connected with an electric connector (2) through cables.

2. A single metal tube capacitive liquid level sensor according to claim 1, wherein, The hollow conductive single pipe (3) comprises a first conductive half pipe (31) and a second conductive half pipe (32) spliced with each other, and an insulating piece (33) is arranged between the spliced surfaces of the first conductive half pipe (31) and the second conductive half pipe (32).

3. A single metal tube capacitive liquid level sensor according to claim 2, wherein, End covers (34) are respectively and tightly installed on the top portions of the first conductive half pipe (31) and the second conductive half pipe (32), and the end covers (34) are connected with the electric connector (2) through cables.

4. A single metal tube capacitive liquid level sensor according to any one of claims 1-3, characterized in that, The inductance part (6) comprises a floating bushing (61) and an inductance coil (62), the floating bushing (61) is slidingly sleeved on the outside of the hollow cylinder (4), a winding groove is arranged on the outer side surface of the floating bushing (61), the inductance coil (62) is wound in the winding groove, and the inductance coil (62) is connected with the electric connector (2) through a cable.

5. A single metal tube capacitive liquid level sensor according to claim 4, wherein, The outside of the inductance coil (62) is covered with an insulating sleeve (63).

6. A single metal tube capacitive liquid level sensor according to any one of claims 1-3, characterized in that, The inside of the hollow cylinder (4) is provided with a cavity, the cavity is filled with floating oil, and the magnetic floating part (5) is suspended in the floating oil.

7. A single metal tube capacitive liquid level sensor according to claim 6, wherein, The magnetic floating part (5) comprises a magnetic float or a glass capsule filled with a magnetic liquid.

8. A single metal tube capacitive liquid level sensor according to any one of claims 1-3, characterized in that, The outside of the insulating heat shrink tube (7) is slidingly provided with a floating disc (8), and the bottom of the floating disc (8) is provided with the first electrode (100).

9. A single metal tube capacitive liquid level sensor according to claim 8, wherein, The floating disc (8) comprises an inner disc (81), an outer disc (82) and floating balls (83), the inner disc (81) is slidingly sleeved on the outside of the insulating heat shrink tube (7), the outer disc (82) is sleeved on the outer side of the inner disc (81), and a plurality of floating balls (83) are rollingly arranged between the outer disc (82) and the inner disc (81).

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