Liquid level measuring device

Abstract

The invention discloses a liquid level measuring device which comprises a vertically arranged guide rod, the guide rod is provided with a hollow cavity with a sealed bottom end, a plurality of Hall sensors connected to a circuit are arranged in the hollow cavity, the Hall sensors are arranged in the guide rod from top to bottom in the vertical direction at approximately equal intervals in an array mode, each Hall sensor corresponds to a set height, and the Hall sensors are connected with the circuit. The guide rod is sleeved with an annular floater, an annular magnet is arranged in the annular floater, the annular magnet surrounds the outer wall of the guide rod, and the annular floater can float on the surface of liquid and move up and down along the guide rod along with the position change of the surface of the liquid, so that the annular magnet in the annular floater is driven to move up and down along the guide rod. The annular magnet triggers the Hall sensor closest to the annular magnet in the guide rod, so that the Hall sensor generates an electric signal, and the height position of the liquid surface is sensed through the height position of the Hall sensor triggered by the annular magnet. And the liquid level of the reagent in the reagent bottle can be accurately measured and monitored in real time.

Description

Technical Field

[0001] The invention relates to the technical field of medical detection instruments, and in particular to a liquid level measuring device, and in particular to a liquid level measuring device for monitoring the liquid level in a reagent bottle used in conjunction with an analytical detector. Background Art

[0002] In the prior art, many applications require measuring whether the liquid has reached a certain position, and the measurement of the liquid level is usually achieved through a liquid level sensor, that is, a liquid level measuring device. Existing liquid level sensors include magnetic flip, float, immersion, ultrasonic, magnetic induction, etc. The corresponding sensor can be selected according to different range requirements, protection levels, container pressure, signal output methods, etc. Some liquid level sensors are magnetic sensors, and even worse, Hall sensors are used as liquid level sensors.

[0003] In the field of biochemical analysis, some tests require multiple reagents to be added in sequence, and the corresponding analytical detectors are usually equipped with reagent bottles containing different reagents. According to the program settings, the analytical detector draws liquid reagents from different reagent bottles and adds them to the reaction area. Common analytical detectors include fully automatic biochemical analyzers, fully automatic chemiluminescence analyzers, fluorescent quantitative PCR analyzers, fully automatic nucleic acid molecular hybridization instruments, etc. The following takes the nucleic acid molecular hybridization instrument as an example for further explanation.

[0004] Nucleic acid molecular hybridization is one of the most basic methods of genetic diagnosis. Its basic principle is that complementary DNA single strands can combine into double strands under certain conditions, that is, they can hybridize. This combination is specific, that is, it is carried out strictly in accordance with the principle of base complementarity. It can be carried out not only between DNA and DNA, but also between DNA and RNA. Therefore, when a probe is made with a nucleic acid sequence of a known gene and is brought into contact with denatured single-stranded genomic DNA, if the bases of the two are completely matched, they complementarily combine into double strands, thereby indicating that the genomic DNA being tested contains a known gene sequence.

[0005] The workflow of the fully automatic nucleic acid molecular hybridization instrument is to simulate the manual operation mode of the entire hybridization reaction. It needs to complete multiple steps such as multiple additions of multiple reagents, insulation, shaking, color development, etc., and connect each reaction step in sequence according to the hybridization reaction process. It automatically completes an analysis project according to the preset program, and finally performs color development analysis on the membrane strip. The test results are used to determine whether it contains specific DNA, and based on this, it is determined whether the person being tested is infected with the virus or whether he or she carries a specific gene.

[0006] Generally, the detection steps of the fully automatic nucleic acid molecular hybridization instrument are as follows: 1. Place the reaction cup with the membrane strip in the cup groove on the reaction disk. 2. The instrument uses an injection pump to inject solution I in the reagent bottle into the reaction cup through the injection needle. 3. After solution I is injected into the reaction cup, the sample to be analyzed is injected into each reaction cup in turn. After the sample injection is completed, the hybridization process is started (about 30 minutes). 4. During the hybridization process, the reaction disk drives the liquid in the reaction cup to be fully mixed through reciprocating rotation to ensure that the reaction can proceed smoothly. 5. After the hybridization process is completed, the reaction cup is rotated to the bottom of the aspiration needle in turn, and the lifting mechanism lowers the aspiration needle to the bottom of the reaction cup, and then the residual reaction liquid in the cup is sucked away by the waste liquid pump. 6. The reaction cup is then rotated to the bottom of the injection needle in turn, and the injection pump injects solution II in the reagent bottle containing solution II into the reaction cup through the injection needle. 7. After the injection of solution II is completed, the membrane washing process is started (about 10 minutes). During the membrane washing process, the reaction disk drives the liquid in the reaction cup to be fully mixed by reciprocating rotation to ensure that the reaction can proceed smoothly. 8. After the membrane washing process is completed, the reaction cup rotates to the bottom of the liquid aspiration needle in turn, and the lifting mechanism lowers the liquid aspiration needle to the bottom of the reaction cup, and then the residual reaction liquid in the cup is sucked away by the waste liquid pump. 9. The reaction cup is then transferred to the bottom of the liquid injection needle in turn, and the liquid injection pump injects the binding liquid in the reagent bottle containing the binding liquid into the reaction cup through the liquid injection needle. 10. After the injection of the binding liquid is completed, the binding process is started (about 10 minutes). During the catalytic process, the reaction disk drives the liquid in the reaction cup to be fully mixed by reciprocating rotation to ensure that the reaction can proceed smoothly. 11. After the binding process is completed, the reaction cup rotates to the bottom of the liquid aspiration needle in turn, and the lifting mechanism lowers the liquid aspiration needle to the bottom of the reaction cup, and then the residual reaction liquid in the cup is sucked away by the waste liquid pump. 12. The reaction cup is then rotated to the bottom of the injection needle, and the injection pump injects solution I in the reagent bottle containing solution I into the reaction cup through the injection needle. 13. After the injection of solution I is completed, the first cleaning process is started (about 10 minutes). During the cleaning process, the reaction disk drives the liquid in the reaction cup to be fully mixed by reciprocating rotation to ensure that the reaction can proceed smoothly. 14. After the cleaning process is completed, the reaction cup is rotated to the bottom of the aspiration needle in turn, and the lifting mechanism lowers the aspiration needle to the bottom of the reaction cup, and then the residual reaction liquid in the cup is sucked away by the waste liquid pump. 15. The reaction cup is then rotated to the bottom of the injection needle in turn, and the injection pump injects solution III in the reagent bottle containing solution III into the reaction cup through the injection needle. 16. After the injection of solution III is completed, the second cleaning process is started (about 3 minutes). During the cleaning process, the reaction disk drives the liquid in the reaction cup to be fully mixed by reciprocating rotation to ensure that the reaction can proceed smoothly. 17. After the cleaning process is completed, the reaction cup is rotated to the bottom of the aspiration needle in turn, the lifting mechanism lowers the aspiration needle to the bottom of the reaction cup, and then the residual reaction liquid in the cup is sucked away by the waste liquid pump.18. The reaction cup is then rotated to the bottom of the injection needle, and the injection pump injects the color-developing solution in the color-developing solution reagent bottle into the reaction cup through the injection needle. 19. After the color-developing solution is injected, the color development process is started (about 10 minutes). During the color development process, the reaction disk drives the liquid in the reaction cup to be fully mixed by reciprocating rotation to ensure that the reaction can proceed smoothly. 20. After the color development process is completed, the reaction cup is rotated to the bottom of the aspiration needle in turn, and the lifting mechanism lowers the aspiration needle to the bottom of the reaction cup, and then the residual reaction liquid in the cup is sucked away by the waste liquid pump. 21. The reaction cup is then rotated to the bottom of the injection needle in turn, and the injection pump injects the purified water in the reagent bottle into the reaction cup through the injection needle. 22. After the injection of purified water is completed, the termination color development process is started (about 3 minutes). During the termination color development process, the reaction disk drives the liquid in the reaction cup to be fully mixed by reciprocating rotation to ensure that the reaction can proceed smoothly. 23. After the color development process is terminated, the reaction cup is rotated to the bottom of the aspiration chamber, and the lifting mechanism lowers the aspiration needle to the bottom of the reaction cup, and then the residual reaction liquid in the cup is sucked away by the waste liquid pump. 24. After the purified water in the reaction cup is sucked clean, the membrane strips in the reaction cup are taken out in turn, and the experimental results are judged by the color development position on the membrane strips.

[0007] The detection process of the entire hybridization instrument involves multiple steps of collaboration between multiple components. If any component or step has a problem, the detection result will be inaccurate or incorrect. Among them, multiple reagents are loaded in separate reagent bottles, which are placed in the hybridization instrument. After the injection needle of the hybridization instrument moves to a reagent bottle to absorb the reagent and add it to the reaction cup of the hybridization instrument, after completing a reaction detection, the liquid aspiration needle goes to the reagent bottle again to absorb the reagent for the next reaction detection. Therefore, the amount of liquid in each reagent bottle needs to be monitored to ensure that there are enough reagents in the reagent bottle, so as to ensure that the detection of the entire hybridization instrument proceeds smoothly. Usually, these reagent bottles are equipped with liquid level sensors or liquid level measuring devices to measure the liquid level of the liquid. The existing actual liquid level monitoring method is to install a Hall sensor at the highest liquid level or the lowest liquid level in the reagent bottle to monitor the liquid level. It can only detect a certain liquid level monitoring, and cannot achieve multi-point or continuous liquid level monitoring. There will be insufficient liquid volume of a certain reagent, which affects the detection result of the entire hybridization instrument. Summary of the invention

[0008] To achieve the above-mentioned purpose, the present invention provides a liquid level measuring device, which can enable the reagent liquid level in the reagent bottle to be accurately measured and detected in real time.

[0009] The present invention provides a liquid level measuring device, comprising a vertically placed guide rod, wherein the guide rod has a hollow cavity sealed at the bottom end, wherein a plurality of Hall sensors respectively connected to a circuit are arranged in the hollow cavity, wherein the plurality of Hall sensors are arranged in an array from top to bottom in the vertical direction in the guide rod at approximately equal intervals, wherein each Hall sensor corresponds to a set height, wherein an annular float is disposed on the outer sleeve of the guide rod, wherein an annular magnet is disposed in the annular float, wherein the annular magnet surrounds the outer wall of the guide rod, wherein the annular float can float on the liquid surface and move up and down along the guide rod following the change of the liquid surface position, thereby driving the annular magnet in the annular float to move up and down along the guide rod, wherein the annular magnet triggers the Hall sensor in the guide rod that is closest to the annular magnet, causing it to generate an electrical signal, thereby sensing the height position of the liquid surface through the height position of the Hall sensor triggered by the annular magnet, wherein the plurality of Hall sensors arranged in the above manner realize multi-point real-time detection of the liquid surface height position.

[0010] A further technical solution is: the Hall sensor is installed vertically relative to the guide rod, so that the angle between the Hall sensor and the guide rod is 90 degrees.

[0011] A further technical solution is that the Hall sensor is installed obliquely relative to the guide rod, so that there is no induction blank area between adjacent Hall sensors, and thus there is no magnetic induction blank area in the magnetic induction detected by the annular magnet, forming continuous detection.

[0012] A further technical solution is: the Hall sensor is installed at a downward tilt relative to the guide rod, and the tilt angle is set so that a horizontal line extending from the end of the previous Hall sensor can touch the next Hall sensor; or the Hall sensor is installed at an upward tilt relative to the guide rod, and the tilt angle is set so that a horizontal line extending from the end of the next Hall sensor can touch the previous Hall sensor.

[0013] A further technical solution is that the tilt angle is between 30 degrees and 80 degrees, that is, the angle between the Hall sensor and the guide rod is between 30 degrees and 80 degrees.

[0014] In a further technical solution, the further technical solution is: the spacing between the Hall sensors is between 3-30 mm.

[0015] In a further technical solution, the further technical solution is: the spacing between the Hall sensors is between 3-7 mm.

[0016] A further technical solution is: the liquid level measuring device also includes a liquid pipe, the guide rod and the liquid pipe are fixed relatively parallel, the bottom ends of the guide rod and the liquid pipe are fixed by a fixing block, and the top ends of the guide rod and the liquid pipe are fixed by a bracket.

[0017] A further technical solution is: the liquid level measuring device also includes a temperature sensor electrically connected to the circuit, and the temperature sensor is arranged at the bottom of the hollow cavity of the guide rod and below the Hall sensor.

[0018] A further technical solution is that the circuit extends out of the open end of the hollow cavity of the guide rod through the electric wire, and the electric wire and the open end of the hollow cavity of the guide rod are sealed by a sealing rubber.

[0019] A further technical solution is that the liquid pipe has a cavity with two ends open, wherein the top of the cavity is connected to a hose.

[0020] A further technical solution is: it also includes a cover body covering the bottle body containing the liquid, and the cover body is sealed and fixedly connected to the conduit and the liquid pipe respectively.

[0021] Beneficial effects of the present invention: The liquid level measuring device of the present invention realizes multi-point detection by arranging a plurality of equally spaced Hall sensors in the vertical direction, or makes the Hall sensor detect the magnetic induction of the annular magnet to eliminate the induction blank area, thereby forming continuous detection. The reagent level in the reagent bottle can be accurately measured and monitored in real time, avoiding the inaccurate or imprecise liquid level measurement caused by the magnetic induction blank area. In addition, the present invention integrates the liquid level sensing component and the temperature sensing component into one, making the device highly integrated and greatly reducing the size of the device. The present invention is particularly suitable for large-scale detection instruments that have high requirements for detection accuracy and are used in conjunction with multiple mechanisms, such as fully automatic nucleic acid molecular hybridization instruments, to avoid the situation where a problem with one reagent causes problems with the detection data of the entire large instrument. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic cross-sectional view of the structure of the present invention.

[0023] Figure 2 It is a cross-sectional schematic diagram of the present invention when measuring liquid level.

[0024] Figure 3 yes Figure 2 A partial enlarged schematic diagram of .

[0025] Figure 4 yes Figure 3 A partial enlarged schematic diagram of another embodiment is shown with different tilt angles.

[0026] Figure 5 yes Figure 4 A partial enlarged schematic diagram of another embodiment is shown, in which the spacing between Hall sensors is different at the same tilt angle.

[0027] Figure 6 yes Figure 3 A partial enlarged schematic diagram of another embodiment is shown with another different tilt angle.

[0028] Figure 7 It is a partial cross-sectional schematic diagram of another embodiment of the present invention.

[0029] Figure 8 It is a schematic cross-sectional view of the structure of another embodiment of the present invention.

[0030] Fig. 9 yes Figure 8 A partial enlarged schematic diagram of .

[0031] Fig.10 The present invention is applied to the structural schematic diagram of a fully automatic nucleic acid molecule hybridization instrument.

[0032] Figure numerals: liquid level measuring device 300, guide rod 20, hollow cavity 22, open end 23, circuit board 10, Hall sensor 30, horizontal line 31 extending from the end of the Hall sensor, angle 32 formed by the Hall sensor and the guide rod, annular float 40, annular magnet 50, temperature sensor 60, fixing block 70, bracket 71, liquid path tube 80, cavity 81, gaskets 21, 82, wire 90, reagent bottle 100, bottle body 11, cover body 12, hybridization instrument 200, reaction disk 210, magnetic induction blank area 33, reagent 15, liquid surface of reagent 16, sealing rubber 91, hose 83. DETAILED DESCRIPTION

[0033] The following further describes the structures or technical terms used in the present invention. In the following detailed description, the reference text attached to the legend is a part of this part, which is described in the way of illustrating the specific specific scheme that the present invention may be implemented. We do not exclude that the present invention can also implement other specific schemes and change the structure of the present invention without violating the scope of use of the present invention.

[0034] like Figure 1-Figure 7As shown, the liquid level measuring device 300 of the present invention comprises a guide rod 20 and a liquid line tube 80, wherein the guide rod 20 and the liquid line tube 80 are fixed parallel to each other and placed vertically. In a specific embodiment, the top ends of the guide rod and the liquid line tube are fixed by a bracket 71, and the bottom ends of the guide rod and the liquid line tube are fixed by a fixing block 70. The guide rod 20 has a hollow cavity 22 with a bottom seal, a circuit board 10 is arranged in the hollow cavity, and a plurality of Hall sensors 30 connected to the circuit board 20 and electrically conductive are arranged in an array from top to bottom in the vertical direction. In a specific embodiment, the plurality of Hall sensors 30 are arranged at equal intervals. An annular float 40 is provided on the outer wall of the guide rod 20, and an annular magnet (also known as a "magnetic ring") 50 is provided in the annular float, and the annular magnet 50 surrounds the outer wall of the guide rod 20. The circuit board 10 extends out of the open end 23 of the hollow cavity 22 of the guide rod through the wire 90, and the wire and the open end 23 of the hollow cavity of the guide rod are sealed by a sealing rubber 91. The circuit of the circuit board and the wire is connected to the Hall sensor to complete the power supply and measurement of the sensor.

[0035] Because the Hall sensor is a magnetic field sensor made according to the Hall effect, the annular magnet in the annular float forms magnetic induction with the Hall sensor. The annular float 40 floats on the liquid surface 16 of the reagent 15. When the liquid position of the reagent changes, the annular float continues to float on the liquid surface 16 following the change in the liquid level, so that the annular float moves in the vertical direction relative to the guide rod 20, thereby driving the annular magnet 50 in the annular float to move up and down along the guide rod 20. The annular magnet 50 triggers the Hall sensor 30 closest to it, causing the Hall sensor to send out an electrical signal. Since the electrical signals sent by the Hall sensors at different height positions are triggered to correspond to the positions of the annular magnets, and the positions of the annular magnets correspond to the liquid surface positions through the height of the annular float, the height of the triggered Hall sensor corresponds to the height of the liquid surface position. Therefore, multiple vertically arranged Hall sensors 30 can sense the height of the liquid position at multiple points. That is to say, when the annular magnet 50 moves up and down along the guide rod 20, it can be detected by the Hall sensor corresponding to the position of the annular magnet in the guide rod, so that the circuit obtains the position of the magnet and the annular float through the detection of the Hall sensor 30 at a certain position, thereby obtaining the liquid level value, thereby realizing multi-point real-time detection of the liquid level value.

[0036] The Hall sensors 30 are arranged in an array with approximately equal spacing in the guide rod 20, so that the entire guide rod has Hall sensors. Therefore, when the annular magnet on the outer wall of the guide rod moves to the nearest Hall sensor, the two form magnetic induction. In theory, any position on the entire guide rod 20 can be sensed. In one embodiment, Figure 8 and Fig. 9As shown, the Hall sensors 30 are arranged at equal intervals perpendicular to the guide rod 20. In such an arrangement, there is a distance between the two Hall sensors, and the magnetic induction within the distance easily forms a blank area 33. However, as long as the size of the blank area 33 is reasonably controlled so that the annular magnet can sense at least one Hall sensor during the up and down movement, the liquid level detection of this embodiment is still reflected as multi-point or even continuous.

[0037] In a preferred embodiment, multiple Hall sensors are installed obliquely relative to the guide rod, so that there is no induction blank area when the Hall sensor detects the magnetic induction of the annular magnet, forming continuous detection. At the same time, the oblique installation of the Hall sensor can increase the distance between two adjacent Hall sensors to a certain extent, that is, the number of Hall sensors arranged in the guide rod of the same height can be reduced. It can also reduce the size of the hollow cavity of the guide rod.

[0038] In a specific embodiment, Figure 3-Figure 6 As shown, the Hall sensor is set at a downwardly inclined angle relative to the guide rod so that a horizontal line 31 extending from the end of the previous Hall sensor can contact the next Hall sensor.

[0039] In another specific embodiment, Figure 7 As shown, the Hall sensor is set at an upwardly inclined angle relative to the guide rod so that a horizontal line 31 extending from the end of a next Hall sensor can contact the previous Hall sensor.

[0040] like Figure 3-Figure 5 As shown, when the Hall sensors are arranged to be tilted downward relative to the guide rod, they are also arranged in an equidistant array. At this time, the lowest point of the previous Hall sensor is lower than the highest point of the next Hall sensor, or the lowest point of the previous Hall sensor is equal to the highest point of the next Hall sensor, that is, the horizontal line 31 extending from the end of the previous Hall sensor can touch the next Hall sensor. In this way, even if there is a gap between two adjacent Hall sensors, the previous Hall sensor and / or the next Hall sensor exists at the gap, so that there is no induction blank area when the Hall sensor detects the magnetic induction of the annular magnet, forming continuous detection.

[0041] like Figure 7As shown, when the Hall sensors are arranged to tilt upward relative to the guide rod, the highest point of the next Hall sensor is higher than the lowest point of the previous Hall sensor, or the highest point of the next Hall sensor is equal to the lowest point of the previous Hall sensor, that is, the horizontal line 31 extending from the end of the next Hall sensor can touch the previous Hall sensor. Similarly, it is ensured that even if there is a gap between two adjacent Hall sensors, there is a previous Hall sensor and / or the next Hall sensor at the gap, so that there is no induction blank area when the Hall sensor detects the magnetic induction of the ring magnet, forming continuous detection.

[0042] Of course, the angle at which the Hall sensor is tilted upward or downward corresponds to the spacing of the Hall sensors. For example, when the spacing H of the Hall sensors is relatively large, the angle 32 at which the Hall sensor is tilted relative to the guide rod can be set smaller, such as Figure 3 and Figure 5 Alternatively, if the spacing H between the Hall sensors is relatively small, the angle 32 between the Hall sensors and the guide rod can be set larger, such as Figure 6 shown.

[0043] In some embodiments, the spacing H of the Hall sensor can be set between 3-30 mm, or between 3-25 mm, or between 3-20 mm, or between 3-15 mm, or between 3-10 mm, or between 3-7 mm. The smaller the value of the spacing H is within the above selected range, the more accurate the sensing of the liquid surface position. The angle (included angle) of the Hall sensor relative to the guide rod is between 30 degrees and 80 degrees.

[0044] The liquid level measuring device of the present invention is provided with a temperature sensor 60 connected with an electric circuit, and the temperature sensor 60 is arranged at the bottom of the hollow cavity of the guide rod and is also located below the Hall sensor. In some embodiments, the temperature sensor is a thermistor. In other embodiments, the liquid level sensing component (Hall sensor) and the temperature sensing component are integrated into one.

[0045] In the present invention, the liquid pipe 80 has a cavity 81 with two ends opened, wherein the top of the cavity is connected to a hose 83 .

[0046] The liquid level measuring device 300 is installed in the reagent bottle 100, and the reagent bottle 100 includes a bottle body 11 and a cover body 12, which are sealed and connected. In some embodiments, the cover body 12 is fixed on the liquid level measuring device 300. In a specific embodiment, the guide rod and the liquid line pipe are sealed and fixed on the cover body through the gasket 21 and the gasket 82, respectively, so that the cover body is fixedly connected to the liquid level measuring device.

[0047] In other embodiments, Fig.10As shown, the liquid level measuring device 300 is installed in the reagent bottle 100 of the hybridization instrument 200 to monitor the liquid level of the reagent in the reagent bottle. A liquid level measuring device 300 is installed in each reagent bottle, so that the liquid levels of multiple reagent bottles 100 of the hybridization instrument 200 can be monitored, ensuring that the detection of the hybridization instrument 200 is carried out smoothly and accurately.

Claims

1. A liquid level measuring device, characterized in that: The invention comprises a vertically placed guide rod, wherein the guide rod has a hollow cavity sealed at the bottom end, wherein a plurality of Hall sensors respectively connected to the circuit are arranged in the hollow cavity, wherein the plurality of Hall sensors are arranged in an array from top to bottom in the vertical direction at approximately equal intervals, wherein each Hall sensor corresponds to a set height, and an annular float is arranged on the outer sleeve of the guide rod, wherein an annular magnet is arranged in the annular float, wherein the annular magnet surrounds the outer wall of the guide rod, and wherein the annular float can float on the surface of the liquid and move up and down along the guide rod following the change of the position of the liquid surface, thereby driving the annular magnet in the annular float to move up and down along the guide rod, wherein the annular magnet triggers the Hall sensor in the guide rod which is closest to the annular magnet, causing it to generate an electrical signal, thereby sensing the height position of the liquid surface through the height position of the Hall sensor triggered by the annular magnet, and wherein the plurality of Hall sensors arranged in the above manner realize multi-point real-time detection of the height position of the liquid surface.

2. The liquid level measuring device according to claim 1, characterized in that: The Hall sensor is installed vertically relative to the guide rod, so that the angle between the Hall sensor and the guide rod is 90 degrees.

3. The liquid level measuring device according to claim 1, characterized in that: The Hall sensor is installed obliquely relative to the guide rod.

4. The liquid level measuring device according to claim 3, characterized in that: The Hall sensor is installed with a downward tilt relative to the guide rod, and the tilt angle is set so that a horizontal line extending from the end of a previous Hall sensor can touch a next Hall sensor; or the Hall sensor is installed with an upward tilt relative to the guide rod, and the tilt angle is set so that a horizontal line extending from the end of a next Hall sensor can touch a previous Hall sensor.

5. The liquid level measuring device according to claim 3, characterized in that: The angle between the Hall sensor and the guide rod is between 30 degrees and 80 degrees.

6. The liquid level measuring device according to claim 2 or 3, characterized in that: The spacing between the Hall sensors is between 3-30mm.

7. The liquid level measuring device according to claim 2 or 3, characterized in that: The spacing between the Hall sensors is between 3-7mm.

8. The liquid level measuring device according to claim 1, characterized in that: The liquid level measuring device also includes a liquid pipe. The guide rod and the liquid pipe are fixed relatively parallel to each other. The bottom ends of the guide rod and the liquid pipe are fixed by a fixing block, and the top ends of the guide rod and the liquid pipe are fixed by a bracket.

9. The liquid level measuring device according to claim 1, characterized in that: The liquid level measuring device also includes a temperature sensor which is electrically connected to the circuit. The temperature sensor is arranged at the bottom of the hollow cavity of the guide rod and is located below the Hall sensor.

10. The liquid level measuring device according to claim 9, characterized in that: The circuit extends out of the open end of the hollow cavity of the guide rod through the electric wire, and the electric wire and the open end of the hollow cavity of the guide rod are sealed by a sealing rubber.

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