Liquid level sensor

Abstract

The utility model provides a liquid level sensor which comprises an inner pipe and an outer pipe, the outer pipe is coaxially arranged on the outer side of the inner pipe, a stud is installed in the middle of the inner pipe and used for fixing the inner pipe, a plurality of liquid nitrogen inflow holes are formed in the outer pipe, the top of the inner pipe is in output connection with a positive electrode lead, and the top of the outer pipe is in output connection with a negative electrode lead. A first insulation terminal is arranged at the top of the area between the inner pipe and the outer pipe, the inner wall of the first insulation terminal is in threaded connection with the outer wall of the inner pipe, the outer wall of the first insulation terminal abuts against the inner wall of the outer pipe, and a third insulation terminal is arranged at the bottom of the area between the inner pipe and the outer pipe and comprises a supporting part and a third connecting part. The supporting part is used for supporting the bottoms of the inner pipe and the outer pipe, the inner wall of the third connecting part is in threaded connection with the outer wall of the inner pipe, the outer wall of the third connecting part abuts against the outer wall of the outer pipe, and the third insulating terminal is used for fixing the bottoms of the inner pipe and the outer pipe. According to the scheme, the structure of the liquid level sensor is simplified, the production and machining process of the liquid level sensor is simpler, more convenient and easier to operate, and the production efficiency is improved.

Description

Technical Field

[0001] This application relates to the technical field of sensors, and particularly to a liquid level sensor. Background Art

[0002] Liquid nitrogen is an inert, colorless, odorless, low-viscosity, non-corrosive, and non-flammable liquid. Deep cryogenic liquid nitrogen storage utilizes the physical properties of liquid nitrogen to freeze and preserve biological samples. Due to the special properties of biological samples, high precision and safety requirements are imposed on liquid nitrogen storage containers. However, no matter how good the sealing performance of a liquid nitrogen tank is, over time, liquid nitrogen will be lost and needs to be replenished in a timely manner. Therefore, it is necessary to monitor the liquid nitrogen level in real time.

[0003] Existing liquid level sensors include an inner tube and an outer tube, and the outer tube is coaxially arranged outside the inner tube. The inner tube is formed by welding two tubes to ensure the minimum deformation during installation. The fixation between the inner tube and the outer tube is achieved by adhesive bonding and then riveting. Such a production and processing method not only complicates the production and processing steps of the liquid level sensor but also increases the production and processing difficulty, resulting in low production efficiency. Summary of the Utility Model

[0004] To solve the above deficiencies of the prior art, this application provides a liquid level sensor, which not only simplifies the structure of the liquid level sensor but also makes its production and processing process simpler and easier to operate, improving production efficiency.

[0005] To achieve the above object, the present utility model adopts the following technologies:

[0006] A liquid level sensor includes an inner tube and an outer tube. The outer tube is coaxially arranged outside the inner tube. A stud is installed in the middle of the inner tube for fixing the inner tube itself. A plurality of liquid nitrogen inlet holes are provided on the outer tube. A positive electrode lead is output-connected to the top of the inner tube, and a negative electrode lead is output-connected to the top of the outer tube. A first insulating terminal is provided at the top of the area between the inner tube and the outer tube. The inner wall of the first insulating terminal is threadedly connected to the outer wall of the inner tube, and the outer wall of the first insulating terminal abuts against the inner wall of the outer tube. A third insulating terminal is provided at the bottom of the area between the inner tube and the outer tube. The third insulating terminal includes a support portion and a third connecting portion. The support portion is used to support the bottoms of the inner tube and the outer tube. The inner wall of the third connecting portion is threadedly connected to the outer wall of the inner tube, and the outer wall of the third connecting portion abuts against the outer wall of the outer tube. The third insulating terminal is used for fixing the bottoms of the inner tube and the outer tube.

[0007] The beneficial effects of the present utility model are as follows: A liquid level sensor provided by the present utility model forms the positive and negative electrodes of the sensor through an inner tube and an outer tube. After being output through the positive and negative electrode leads, the height of the liquid nitrogen filling can be reflected by measuring the capacitance value, thereby realizing the monitoring of the liquid nitrogen level height. Among them, the inner tube does not need to be formed by welding two tubes. Only by fixing it in the middle of one tube with a stud can the deformation during installation be minimized, effectively simplifying the production and processing steps. At the same time, the inner tube and the outer tube are fixed by the first insulating terminal and the second insulating terminal at both ends of the sensor, and the threaded fixing method is adopted, which simplifies the fixing method, facilitates mass production and processing, and improves production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The drawings described herein are only for illustrating the selected embodiments, not all possible implementation schemes, and are not intended to limit the scope of the present utility model.

[0009] Figure 1 It is a three-dimensional view of the overall structure of an embodiment of the present application.

[0010] Figure 2 It is a cross-sectional view of an embodiment of the present application.

[0011] Figure 3 is Figure 2 a partial enlarged view of part A in

[0012] Figure 4 is Figure 2 a partial enlarged view of part B in

[0013] Figure 5 is Figure 2 a partial enlarged view of part C in

[0014] Figure 6 It is a schematic diagram of the installation relationship at the top of an embodiment of the present application.

[0015] Figure 7 It is a schematic diagram of the installation relationship at the bottom of an embodiment of the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0016] To make the objectives, technical solutions, and advantages of the embodiments of the present utility model clearer, the following will describe the embodiments of the present utility model in detail with reference to the drawings. However, the embodiments described herein are only a part of the embodiments of the present utility model, not all of the embodiments.

[0017] An embodiment of the present application provides a liquid level sensor, as Figures 1-7 shown, including an inner tube 1, an outer tube 2, a first insulating terminal 5, and a third insulating terminal 6.

[0018] Both the inner tube 1 and the outer tube 2 are stainless steel tubes. The outer tube 2 is coaxially arranged outside the inner tube 1. The area between the inner tube 1 and the outer tube 2 is used to fill the medium. A stud 3 is installed in the middle of the inner tube 1, and the stud 3 is used for the fixation of the inner tube 1 itself to ensure the minimum deformation during installation. A plurality of liquid nitrogen inlet holes 4 are opened on the outer tube 2. The top of the inner tube 1 is output-connected with a positive electrode lead, and the top of the outer tube 2 is output-connected with a negative electrode lead.

[0019] The first insulating terminal 5 is arranged at the top of the area between the inner tube 1 and the outer tube 2. The inner wall of the first insulating terminal 5 is threadedly connected with the outer wall of the inner tube 1, and the outer wall of the first insulating terminal 5 abuts against the inner wall of the outer tube 2. The first insulating terminal 5 is used for the fixation of the tops of the inner tube 1 and the outer tube 2.

[0020] The third insulating terminal 6 is arranged at the bottom of the area between the inner tube 1 and the outer tube 2. The third insulating terminal 6 includes a support portion 61 and a third connecting portion 62. The support portion 61 is used to support the bottoms of the inner tube 1 and the outer tube 2. The inner wall of the third connecting portion 62 is threadedly connected with the outer wall of the inner tube 1, and the outer wall of the third connecting portion 62 abuts against the outer wall of the outer tube 2. The third insulating terminal 6 is used for the fixation of the bottoms of the inner tube 1 and the outer tube 2.

[0021] Through the first insulating terminal 5 and the third insulating terminal 6, the fixation of the inner tube 1 and the outer tube 2 at the top and bottom is completed, and then the overall fixation of the inner tube 1 and the outer tube 2 is realized. On the one hand, the inner tube 1 and the outer tube 2 are always kept coaxial, so that the radial distance from any point on the outer wall of the inner tube 1 to the inner wall of the outer tube 2 is always kept consistent, reducing the error factors during liquid level measurement. On the other hand, the inner tube 1 and the outer tube 2 will not have relative displacement in the axial direction, avoiding affecting the measurement accuracy. Both the first insulating terminal 5 and the third insulating terminal 6 are nylon processed parts, and the fixation of the inner tube 1 and the outer tube 2 is completed by means of threaded connection, effectively simplifying the fixation method of the inner tube 1 and the outer tube 2, which is beneficial to improving the production efficiency of the liquid level sensor.

[0022] During application, the liquid level sensor is vertically inserted into a stainless steel tank filled with liquid nitrogen, where the bottom of the liquid level sensor contacts the bottom of the stainless steel tank, and the positive and negative electrode leads at the top of the liquid level sensor are connected to the monitoring device, then the real-time monitoring of the liquid nitrogen level can be realized.

[0023] The sensor consists of a positive electrode and a negative electrode to form a capacitor. Among them, the inner tube 1 is the positive electrode of the sensor, and the outer tube 2 is the negative electrode of the sensor. The measured liquid nitrogen can enter between the positive electrode and the negative electrode of the sensor through the liquid nitrogen inlet hole 4 for dielectric filling of the capacitor. When there is no liquid nitrogen between the positive electrode and the negative electrode of the sensor, the medium filled between them is air; when there is liquid nitrogen between the positive electrode and the negative electrode of the sensor, the medium filled between them is liquid nitrogen. Due to the different dielectric constants of air and liquid nitrogen, the capacitance of the capacitor will also change with the change of the filled medium. After being output through the positive and negative electrode leads, the height of the filled liquid nitrogen can be reflected by measuring the capacitance value, so as to realize that the change in the height of liquid nitrogen is reflected as the change in capacitance capacity through the liquid nitrogen sensor.

[0024] Specifically, as Figure 3 and Figure 6 shown, the top of the inner tube 1 is lower than the top of the outer tube 2. The first insulating terminal 5 includes a first fixing part 51 and a first connecting part 52. The first fixing part 51 is coaxially arranged at the top of the first connecting part 52. The first fixing part 51 is used to fix the positive electrode lead of the sensor. The inner wall of the first connecting part 52 is threadedly connected to the outer wall of the inner tube 1, and the outer wall of the first connecting part 52 abuts against the inner wall of the outer tube 2.

[0025] Specifically, a second insulating terminal 7 is sleeved on the top of the first insulating terminal 5. The second insulating terminal 7 includes a second fixing part 71 and a second connecting part 72. The bottom surface of the second fixing part 71 contacts the top of the outer tube 2. The second fixing part 71 is used to fix the negative electrode lead of the sensor. The inner wall of the second connecting part 72 is threadedly connected to the outer wall of the first fixing part 51, and the outer wall of the second connecting part 72 abuts against the inner wall of the outer tube 2.

[0026] By sequentially threadedly connecting the second insulating terminal 7, the first insulating terminal 5 and the inner tube 1, and both the second insulating terminal 7 and the first insulating terminal 5 abut against the inner wall of the outer tube 2, while improving the fixing stability of the inner tube 1 and the outer tube 2, the positive electrode lead and the negative electrode lead are also fixed. Among them, the second insulating terminal 7 is also a nylon processed part.

[0027] Specifically, the outer wall of the second fixing part 71 is flush with the outer wall of the outer tube 2. More specifically, a fixing part 8 is fixedly installed at the connection between the second insulating terminal 7 and the outer wall of the outer tube 2. The fixing part 8 is used for fixing the sensor. The fixing part 8 is an external hexagonal stainless steel part. Since the outer wall of the second fixing part 71 is flush with the outer wall of the outer tube 2 and the bottom surface of the second fixing part 71 is flush with the top of the outer tube 1, with the setting of the fixing part 8, it helps to keep the outer tube 2 and the second insulating terminal 7 coaxial and tightly connected, further improving the fixing stability of the inner tube 1 and the outer tube 2.

[0028] Preferably, a liquid nitrogen inlet hole 4 is opened on the inner tube 1 to increase the amount of filled liquid nitrogen and improve the sensitivity of the sensor.

[0029] Preferably, the liquid nitrogen inlet hole 4 is arranged at the bottom of the outer tube 2. Such an arrangement enables the liquid nitrogen to be more conveniently filled between the inner tube 1 and the outer tube 2, avoiding the situation that the liquid nitrogen cannot enter between the inner tube 1 and the outer tube 2 due to the too high liquid nitrogen inlet hole 4 when the liquid nitrogen is not completely consumed, resulting in the liquid level sensor being unable to measure normally, and effectively expanding the monitoring range of the liquid nitrogen level. Similarly, the liquid nitrogen inlet hole 4 opened on the inner tube 1 is also located at the bottom of the inner tube 1 to facilitate the inflow of liquid nitrogen, thereby improving the sensitivity of the sensor.

[0030] In application, the above is only the preferred embodiment of the present application and is not used to limit the present application. Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application.

Claims

1. A liquid level sensor, comprising an inner tube (1) and an outer tube (2), wherein the outer tube (2) is coaxially arranged on the outer side of the inner tube (1), characterized in that: A bolt (3) is installed in the middle of the inner tube (1), and the bolt (3) is used to fix the inner tube (1) itself. A plurality of liquid nitrogen inlet holes (4) are opened on the outer tube (2). The top output of the inner tube (1) is connected to a positive electrode lead, and the top output of the outer tube (2) is connected to a negative electrode lead. A first insulating terminal (5) is provided at the top of the area between the inner tube (1) and the outer tube (2). The inner wall of the first insulating terminal (5) is threadedly connected to the outer wall of the inner tube (1), and the outer wall of the first insulating terminal (5) is threadedly connected to the outer wall of the outer tube (2). The inner wall of the inner tube (1) and the outer tube (2) are abutted against each other, and a third insulating terminal (6) is provided at the bottom of the area between the inner tube (1) and the outer tube (2). The third insulating terminal (6) comprises a supporting portion (61) and a third connecting portion (62). The supporting portion (61) is used to support the bottom of the inner tube (1) and the outer tube (2). The inner wall of the third connecting portion (62) is threadedly connected to the outer wall of the inner tube (1). The outer wall of the third connecting portion (62) abuts against the outer wall of the outer tube (2). The third insulating terminal (6) is used to fix the bottom of the inner tube (1) and the outer tube (2).

2. A liquid level sensor according to claim 1, characterized in that: The top of the inner tube (1) is lower than the top of the outer tube (2); the first insulating terminal (5) comprises a first fixing portion (51) and a first connecting portion (52); the first fixing portion (51) is coaxially arranged at the top of the first connecting portion (52); the first fixing portion (51) is used to fix the positive electrode lead of the sensor; the inner wall of the first connecting portion (52) is threadedly connected to the outer wall of the inner tube (1); and the outer wall of the first connecting portion (52) is in contact with the inner wall of the outer tube (2).

3. A liquid level sensor according to claim 2, characterized in that: A second insulating terminal (7) is sleeved on the top of the first insulating terminal (5), and the second insulating terminal (7) comprises a second fixing portion (71) and a second connecting portion (72). The bottom surface of the second fixing portion (71) contacts the top of the outer tube (2), and the second fixing portion (71) is used to fix the negative electrode lead of the sensor. The inner wall of the second connecting portion (72) is threadedly connected to the outer wall of the first fixing portion (51), and the outer wall of the second connecting portion (72) abuts against the inner wall of the outer tube (2).

4. A liquid level sensor according to claim 3, characterized in that: The outer wall of the second fixing portion (71) is flush with the outer wall of the outer tube (2).

5. A liquid level sensor according to claim 3, characterized in that: A fixing member (8) is fixedly mounted at the connection between the second insulating terminal (7) and the outer wall of the outer tube (2), and the fixing member (8) is used to fix the sensor.

6. A liquid level sensor according to claim 1, characterized in that: The inner tube (1) is provided with a liquid nitrogen inlet hole (4).

7. A liquid level sensor according to claim 1, characterized in that: The liquid nitrogen inlet hole (4) is arranged at the bottom of the outer tube (2).

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