Capacitive liquid level meter and detection system

Abstract

The utility model relates to a capacitance type liquid level meter and a detection system, and belongs to the field of LNG tank body liquid level detection devices, the capacitance type liquid level meter comprises an outer electrode, an inner electrode and a plurality of insulation supporting points, the two ends of the outer electrode are open, and the interior of the outer electrode is hollow; the inner electrode is arranged in the outer electrode, and the outer side wall of the inner electrode and the inner side wall of the outer electrode are mutually spaced; the insulation supporting points are arranged in the interval space between the inner electrode and the outer electrode at intervals and abut against the outer side wall of the inner electrode and the inner side wall of the outer electrode so that the interval distance between the inner electrode and the outer electrode can be kept, the distance between the two electrodes can be kept stable, and the capacitance value of the liquid level meter cannot be greatly changed due to external force. Therefore, the liquid level measurement precision in the storage tank is ensured.

Description

Technical Field

[0001] The utility model relates to the field of LNG tank liquid level detection devices, in particular to a capacitive liquid level meter and a detection system thereof. Background Art

[0002] Liquid nitrogen, liquid oxygen, liquid hydrogen, LNG and other substances stored in ultra-low temperature tanks usually use capacitive level gauges to detect the volume of the liquid. The principle is based on the relationship between capacitance and liquid height. The height of the liquid is determined by measuring the change in capacitance, and the volume of the liquid is determined based on the size of the tank. The capacitive level gauge places two conductive electrodes in an insulating environment in the tank. When the liquid level in the tank changes, the capacitance changes. By measuring the change in capacitance, the volume of the ultra-low temperature liquid in the tank is measured.

[0003] The capacitance level gauge currently used in ultra-low temperature storage tanks generally uses two electrodes, and the distance between the two electrodes is generally about 2mm. This distance is very easy to change when subjected to external forces, thus affecting the accuracy of liquid level measurement.

[0004] The traditional technical solution is to increase the thickness and strength of the electrode to avoid the distance change caused by the electrode when receiving external force, but this solution increases the cost and makes the sensor heavier, which makes it unacceptable to customers. In other traditional solutions, a ring support is added between the two electrodes, but it will hinder the flow of liquid, thus affecting the liquid level measurement. Utility Model Content

[0005] The utility model aims to solve the problem of the stability of the distance between two electrodes of a capacitance liquid level meter.

[0006] In order to solve the above technical problems, the utility model provides a capacitive liquid level gauge, comprising: an outer electrode, which is open at both ends and hollow inside; an inner electrode, which is arranged inside the outer electrode, and a spacing space is formed between the outer side wall of the inner electrode and the inner side wall of the outer electrode; a plurality of insulating support points, which are arranged at intervals in the spacing space between the inner electrode and the outer electrode; the insulating support points are in contact with the outer side wall of the inner electrode and the inner side wall of the outer electrode to maintain the spacing distance between the inner electrode and the outer electrode.

[0007] Optionally, the insulating support points are provided in a plurality of groups, and the plurality of groups are arranged at intervals along the height direction of the inner electrode, each group of the insulating support points is arranged at the same height of the inner electrode, and each group has a plurality of insulating support points arranged at circumferential intervals around the inner electrode.

[0008] Optionally, each group has four insulating support points, and the four insulating support points are evenly distributed around the circumference of the inner electrode.

[0009] Optionally, a plurality of mounting holes are provided on the inner electrode, and each mounting hole corresponds to one of the insulating support points.

[0010] Optionally, the insulating support point includes a mounting portion and an abutment portion which are connected to each other; the mounting portion is arranged in the mounting hole of the inner electrode; the abutment portion is located on the outer wall of the inner electrode, and a side of the abutment portion away from the mounting portion is used to abut against the inner wall of the outer electrode.

[0011] Optionally, the mounting portion is cylindrical, the abutting portion is cap-shaped, and the mounting portion is transversely penetrated into the mounting hole of the inner electrode and protrudes from the inner side wall of the inner electrode.

[0012] Optionally, the outer electrode and the inner electrode are both cylindrical metal tubes.

[0013] Optionally, the capacitive liquid level gauge further comprises a sleeve, which is disposed at both ends of the outer electrode and is used to be connected to an inner wall of a storage tank for transporting liquefied gas.

[0014] Optionally, the capacitive liquid level meter also includes a processor, which is electrically connected to the inner electrode and the outer electrode. The processor can identify the capacitance change of the inner electrode and the outer electrode, and calculate the liquid level height in the space between the inner electrode and the outer electrode based on the capacitance change.

[0015] The present embodiment provides a detection system, comprising: a storage tank, wherein a containing chamber is provided inside the storage tank; the capacitive liquid level gauge as described above, wherein the inner electrode and the outer electrode of the capacitive liquid level gauge are arranged in the containing chamber of the storage tank; the interval space between the inner electrode and the outer electrode is connected to the containing chamber, so that the liquid level height of the interval space changes with the liquid level height in the storage tank; the liquid level height in the storage tank is calculated by calculating the liquid level height in the capacitive liquid level gauge.

[0016] It can be seen from the above technical solution that the beneficial effects of the utility model are:

[0017] The present application provides a capacitive liquid level meter, comprising an outer electrode, an inner electrode and a plurality of insulating support points. The plurality of insulating support points are arranged in the spacing space between the inner electrode and the outer electrode. The present application provides a reliable, simple and low-cost support scheme, which keeps the spacing between the two electrodes stable without affecting the passage of liquid, and the capacitance value of the liquid level meter will not change significantly due to external force, thereby ensuring the accuracy of liquid level measurement in the storage tank. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a structural schematic diagram of a liquid level detection system for a storage tank;

[0019] Figure 2 for Figure 1 A schematic diagram of the half-section structure of the capacitive level gauge in the detection system;

[0020] Figure 3 for Figure 1 The other half of the cross-section structure of the capacitive level meter in the detection system;

[0021] Figure 4 for Figure 3 A schematic diagram of the enlarged structure of the capacitance level gauge;

[0022] Figure 5 for Figure 3 Schematic diagram of the front cross-section structure of the medium capacitance level gauge;

[0023] Figure 6 for Figure 3 Schematic diagram of the top cross-sectional structure of a medium capacitance level gauge.

[0024] The following are the descriptions of the reference numerals:

[0025] 100. Capacitive liquid level gauge; 110. External electrode; 120. Internal electrode; 121. Spacing space; 130. Insulating support point; 131. Mounting portion; 132. Abutting portion; 140. Sleeve; 150. Connecting wire; 200. Storage tank; 210. Accommodating chamber. DETAILED DESCRIPTION

[0026] Typical embodiments that embody the features and advantages of the present invention will be described in detail in the following description. It should be understood that the present invention can have various changes in different embodiments without departing from the scope of the present invention, and the descriptions and illustrations therein are essentially for illustrative purposes rather than for limiting the present invention.

[0027] In the description of the present application, it should be understood that in the embodiments shown in the drawings, the indications of directions or positional relationships (such as up, down, left, right, front and back, etc.) are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the devices or elements referred to must have a specific orientation, be constructed and operate in a specific orientation. These descriptions are appropriate when these elements are in the positions shown in the drawings. If the descriptions of the positions of these elements change, the indications of these directions also change accordingly.

[0028] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0029] At present, liquid nitrogen, liquid oxygen, liquid hydrogen, LNG and other substances stored in ultra-low temperature tanks usually use capacitive level gauges to detect the volume of liquid in the tank. Conventional capacitive level gauges for ultra-low temperature tanks generally use two electrodes, and the distance between the two electrodes is generally about 2mm. This distance is very easy to change when subjected to external forces, thus affecting the accuracy of liquid level measurement.

[0030] Therefore, the distance between the two electrodes of the traditional capacitive level gauge often changes due to insufficient support, thereby affecting the accuracy of the liquid level measurement in the cryogenic storage tank. The present application provides a detection system and a capacitive level gauge to accurately measure the liquid level height of liquefied gases such as liquid nitrogen, liquid oxygen, liquid hydrogen, and LNG in a cryogenic storage tank.

[0031] See also Figure 1 In this embodiment, the detection system includes a storage tank 200 and a capacitive liquid level meter 100 .

[0032] The storage tank 200 is provided with a containing chamber 210 for containing liquefied gas; the capacitive liquid level meter 100 is arranged in the containing chamber 210 of the storage tank 200, and the staff can calculate the liquid level height of the liquefied gas in the storage tank 200 by the capacitance change of the capacitive liquid level meter 100.

[0033] See also Figures 2 to 6 In some embodiments, the capacitive liquid level meter 100 includes an outer electrode 110 , an inner electrode 120 , and a plurality of insulating support points 130 disposed between the outer electrode 110 and the inner electrode 120 .

[0034] The outer electrode 110 is open at both ends and hollow inside. The inner electrode 120 is disposed inside the outer electrode 110 , and the outer wall of the inner electrode 120 is spaced from the inner wall of the outer electrode 110 to form a spacing space 121 .

[0035] A plurality of insulating support points 130 are disposed in the spacing space 121 between the inner electrode 120 and the outer electrode 110. The insulating support points 130 abut against the outer sidewall of the inner electrode 120 and the inner sidewall of the outer electrode 110, respectively, so that the spacing between the inner electrode 120 and the outer electrode 110 remains stable.

[0036] According to the calculation formula of the capacitive level meter 100, C=εS / d (ε is the dielectric constant of the inter-electrode medium, S is the relative area of ​​the two electrodes, and d is the distance between the two electrodes), to accurately measure the liquid level change in the capacitive level meter 100, the capacitance value of the capacitive level meter 100 must be stable. The stability of the capacitance value requires the relative area and distance of the two electrodes of the capacitive level meter 100 to be stable. Generally, the relative area is a fixed value after the electrode size is determined, and it remains unchanged by default; however, the distance between the two electrodes of the traditional level meter often changes due to insufficient support, thereby affecting the accuracy of the liquid level measurement.

[0037] In this embodiment, a plurality of insulating support points 130 are added between the outer electrode 110 and the inner electrode 120 of the capacitive liquid level meter 100, so that point support is formed between the inner electrode 120 and the outer electrode 110; the structure is simple, reliable and low-cost. Under the premise of not affecting the passage of liquid, the distance between the two electrodes is kept stable, and the distance between the two electrodes will not change due to external shaking or the passage of liquefied gas, and the detection accuracy of the liquid level is higher.

[0038] See also Figures 2 to 5 In some embodiments, the outer electrode 110 and the inner electrode 120 are both cylindrical metal tubes.

[0039] The radius of the outer electrode 110 is about 2 mm greater than the radius of the inner electrode 120, so that the inner electrode 120 can be inserted into the outer electrode 110. The inner electrode 120 and the outer electrode 110 are both cylindrical, so that the relative area (S) between the two electrodes can remain unchanged, and even if the inner electrode 120 and the outer electrode 110 rotate around the axis, the relative area will not change, which can effectively ensure the stability of the capacitive liquid level meter 100.

[0040] It is conceivable that in some other embodiments, the cross-sections of the inner electrode 120 and the outer electrode 110 may also be rectangular or other polygonal metal electrodes.

[0041] See also Figure 3 and Figure 5 In some embodiments, a plurality of insulating support points 130 are provided, each group of insulating support points 130 is disposed at the same height of the inner electrode 120 , and each group has a plurality of insulating support points 130 spaced circumferentially around the inner electrode 120 .

[0042] Specifically, the capacitive level gauge 100 in this embodiment is mainly used for measuring the liquid level in the hydraulic storage tank 200, and its length needs to match the height of the accommodation chamber 210 of the storage tank 200. Therefore, the length of the capacitive level gauge 100 is generally long; so multiple groups of insulating support points 130 such as upper, middle and lower are provided in the axis extension direction of the inner electrode 120, which can effectively support and limit the inner electrode 120 and the outer electrode 110.

[0043] See also Figure 5 and Figure 6 In some embodiments, every four insulating support points 130 constitute a group, and the four insulating support points 130 in a group are evenly distributed around the circumference of the inner electrode 120 .

[0044] like Figure 6As shown, the angle between adjacent insulating support points 130 in each group is 90°, which can effectively limit the inner electrode 120 and the outer electrode 110 in all directions to prevent the distance between the two electrodes from changing. In addition, the four insulating support points 130 can also maximize the flow of liquefied gas in the interval space 121 between the two electrodes, and will not cause a short circuit between the inner electrode 120 and the outer electrode 110 due to the accumulation of impurities in the liquid, thereby affecting the stability of the capacitive liquid level meter 100.

[0045] See also Figure 3 and Figure 4 In some embodiments, the inner electrode 120 is provided with a plurality of mounting holes, each of which corresponds to an insulating support point 130. There are also a plurality of groups of mounting holes, so that the insulating support points 130 can be installed in the corresponding mounting holes one by one.

[0046] See also Figure 4 In some embodiments, the insulating support point 130 includes a mounting portion 131 and an abutting portion 132 connected to each other. The mounting portion 131 is inserted into the mounting hole of the inner electrode 120. The abutting portion 132 is located on the outer wall of the inner electrode 120, and a side of the abutting portion 132 away from the mounting portion 131 is used to abut against the inner wall of the outer electrode 110.

[0047] Furthermore, the mounting portion 131 is cylindrical, which matches the shape of the mounting hole. The mounting portion 131 can be transversely inserted into the mounting hole of the inner electrode 120 and protrude from the inner side wall of the inner electrode 120. By docking the cylindrical mounting portion 131 with the circular mounting hole, the insulating support point 130 can be quickly fixed to the inner electrode 120. In addition, the circular mounting hole is also convenient for manufacturing and processing the inner electrode 120.

[0048] When assembling the capacitive liquid level gauge 100, the insulating support point 130 is first fixed to the mounting hole of the inner electrode 120, and then the inner electrode 120 is inserted into the outer electrode 110. In this mounting process, the mounting portion 131 passes through the inner electrode 120 and protrudes from the inner side wall of the inner electrode 120, which can effectively enhance the connection strength between the insulating support point 130 and the inner electrode 120, so that the insulating support point 130 will not fall off from the inner electrode 120.

[0049] Please continue reading Figure 4 In some embodiments, the abutting portion 132 is in a cap shape, and its diameter is slightly larger than the diameter of the mounting portion 131 to form a cap brim. The brim of the abutting portion 132 abuts against the outer wall of the inner electrode 120, and the top of the cap abuts against the inner wall of the outer electrode 110, so as to limit the distance between the inner electrode 120 and the outer electrode 110, so as to effectively prevent the distance between the inner electrode 120 and the outer electrode 110 from changing, thereby improving the stability of the capacitive potentiometer.

[0050] In some embodiments, the insulating support point 130 is made of insulating material that is resistant to high temperatures and deep cold, which can adapt to various extreme environments and can be used and work normally even in an ultra-low temperature storage tank 200.

[0051] It is conceivable that in some other embodiments, the number and shape of the insulating support points 130 can be changed according to the actual product. In some other embodiments, the insulating support points 130 can also be fixed to the outer wall of the inner electrode 120 by bonding, clamping, etc.

[0052] See also Figure 1 and 2 In some embodiments, the capacitive liquid level meter 100 further includes a sleeve 140. The sleeve 140 is disposed at both ends of the outer electrode 110, and the sleeve 140 is used to connect with the inner wall of the storage tank 200 for transporting liquefied gas.

[0053] like Figure 1 As shown, the capacitive liquid level gauge 100 is vertically disposed in the accommodation chamber 210 of the storage tank 200 , and its height is substantially the same as the height of the accommodation chamber 210 inside the storage tank 200 , so that the capacitive liquid level gauge 100 can measure the liquid level height in the storage tank 200 .

[0054] Specifically, the sleeves 140 at both ends of the capacitive liquid level gauge 100 are welded to the inner wall of the storage tank 200 so that the capacitive liquid level gauge 100 can be stably fixed inside the storage tank 200 and will not shake due to shaking of the storage tank 200.

[0055] Moreover, because the inner side wall of the storage tank 200 is arc-shaped, when the sleeve 140 is welded to the inner side wall of the storage tank 200 at several points, the interval space 121 between the inner electrode 120 and the outer electrode 110 of the capacitive liquid level gauge 100 will not be closed, and the interval space 121 and the containing chamber 210 of the storage tank 200 are interconnected, and the liquid level between the inner electrode 120 and the outer electrode 110 can change together with the liquid level of the containing chamber 210 in the storage tank 200.

[0056] See also Figure 3 and Figure 4 In some embodiments, the capacitive liquid level meter 100 also includes a processor, which is disposed on the outside of the storage tank 200. The processor is electrically connected to the inner electrode 120 and the outer electrode 110 to identify the capacitance change between the inner electrode 120 and the outer electrode 110, and calculate the liquid level height of the space between the inner electrode 120 and the outer electrode 110 based on the capacitance change.

[0057] Specifically, the capacitive liquid level meter 100 further includes two independent connecting wires 150. The connecting wires 150 connect the inner electrode 120 and the outer electrode 110 to an external processor respectively.

[0058] Two independent wires are connected to the inner electrode 120 and the outer electrode 110 respectively, and the wires extend along the opening of the storage tank 200, so that the wires are connected to the processor outside the storage tank 200. When the low-temperature liquefied gas in the space 121 between the inner electrode 120 and the outer electrode 110 changes with the liquid level in the storage tank 200, the dielectric constant between the inner electrode 120 and the outer electrode 110 changes, thereby causing the capacitance to change. The processor calculates the liquid level height of the liquefied gas in the storage tank 200 at this time through the capacitance change of the capacitive liquid level meter 100.

[0059] In summary, the present embodiment provides a capacitive liquid level meter 100, including an outer electrode 110, an inner electrode 120 and a plurality of insulating support points 130. The plurality of insulating support points 130 are arranged in a spacing space 121 between the inner electrode 120 and the outer electrode 110 to support and fix the distance between the inner electrode 120 and the outer electrode 110. The support scheme is simple, reliable and low-cost. Under the premise of not affecting the passage of the liquid, the distance between the two electrodes is kept stable, and the capacitance value of the liquid level meter will not change significantly due to external force, thereby ensuring the accuracy of the liquid level measurement in the storage tank 200.

[0060] Although the utility model has been described with reference to several typical embodiments, it should be understood that the terms used are illustrative and exemplary, rather than restrictive. Since the utility model can be implemented in a variety of forms without departing from the spirit or essence of the utility model, it should be understood that the above-mentioned embodiments are not limited to any of the aforementioned details, but should be widely interpreted within the spirit and scope defined by the attached claims, so all changes and modifications falling within the scope of the claims or their equivalents should be covered by the attached claims.

Claims

1. A capacitive liquid level meter, characterized in that: include: The outer electrode has openings at both ends and a hollow interior; An inner electrode is disposed inside the outer electrode, and a spacing space is formed between an outer side wall of the inner electrode and an inner side wall of the outer electrode; A plurality of insulating support points are arranged at intervals in the spacing space between the inner electrode and the outer electrode; the insulating support points abut against the outer side wall of the inner electrode and the inner side wall of the outer electrode to maintain the spacing distance between the inner electrode and the outer electrode.

2. The capacitive liquid level meter according to claim 1, characterized in that: The insulating support points are provided in a plurality of groups, and the plurality of groups are arranged at intervals along the height direction of the inner electrode. Each group of the insulating support points is arranged at the same height of the inner electrode, and each group has a plurality of insulating support points arranged at intervals around the circumference of the inner electrode.

3. The capacitive liquid level meter according to claim 2, characterized in that: Each group has four insulating support points, and the four insulating support points are evenly distributed around the circumference of the inner electrode.

4. The capacitive liquid level meter according to claim 1, characterized in that: The inner electrode is provided with a plurality of mounting holes, and each mounting hole is correspondingly mounted with one of the insulating support points.

5. The capacitive liquid level meter according to claim 4, characterized in that: The insulating support point includes a mounting portion and an abutment portion which are connected to each other; the mounting portion is arranged in the mounting hole of the inner electrode; the abutment portion is located on the outer wall of the inner electrode, and a side of the abutment portion away from the mounting portion is used to abut against the inner wall of the outer electrode.

6. The capacitive liquid level meter according to claim 5, characterized in that: The mounting portion is cylindrical, the abutting portion is cap-shaped, and the mounting portion is transversely arranged in the mounting hole of the inner electrode and protrudes from the inner side wall of the inner electrode.

7. The capacitive liquid level meter according to claim 1, characterized in that: The outer electrode and the inner electrode are both cylindrical metal tubes.

8. The capacitive liquid level meter according to claim 1, characterized in that: The capacitive liquid level gauge further comprises a sleeve, which is arranged at both ends of the outer electrode and is used to be connected to the inner wall of a storage tank for transporting liquefied gas.

9. The capacitive liquid level meter according to claim 1, characterized in that: The capacitive liquid level meter also includes a processor, which is electrically connected to the inner electrode and the outer electrode. The processor can identify the capacitance change of the inner electrode and the outer electrode, and calculate the liquid level height in the space between the inner electrode and the outer electrode according to the capacitance change.

10. A detection system, characterized in that: include: A storage tank having a containing chamber therein; The capacitive liquid level meter according to any one of claims 1 to 9, wherein the inner electrode and the outer electrode of the capacitive liquid level meter are arranged in the containing chamber of the storage tank; the interval space between the inner electrode and the outer electrode is connected to the containing chamber, so that the liquid level height of the interval space changes with the liquid level height in the storage tank; the liquid level height in the capacitive liquid level meter is calculated to infer the liquid level height in the storage tank.

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