Liquid level detection device, container equipment and cable deviation measuring instrument

Abstract

The utility model discloses a liquid level detection device, container equipment and a cable deviation measuring instrument. The liquid level detection device comprises a base plate, a processor unit, a plurality of detection units and a reference assembly, the detection units are distributed on the base plate in the length direction, and each detection unit comprises a heating element and a detection element. According to the liquid level detection device, the heating element abuts against the detection element, the temperature-sensitive resistor abuts against the upper portion of the heating resistor, a threshold value database does not need to be arranged, and the liquid level can be judged only by comparing temperature change values of the temperature-sensitive resistor at different positions; the temperature-sensitive resistor is directly heated, heat is taken away through the heat conduction effect of a medium, rapid response to temperature change is achieved, and therefore the detection period is shortened. The detection unit only comprises a heating resistor and a temperature-sensitive resistor, reference resistors in a peripheral circuit of the temperature-sensitive resistors are arranged on the upper portion of the substrate in a concentrated mode, and the structural width of the lower middle portion of the substrate is reduced so as to adapt to liquid level detection in a narrow space.

Description

Technical Field

[0001] The present application relates to a liquid level detection device, a container device and a cable deflectometer. Background Art

[0002] Existing cable inspection equipment typically uses X-ray tubes for nondestructive testing. These tubes are immersed in insulating oil to ensure safe operation and effective heat dissipation during high-voltage operation. However, due to the device's size and the oil consumption rate (typically requiring refilling every six months to a year), current oil reservoirs are extremely narrow, with a refill aperture of only 10mm to 20mm. This limited space makes it impossible to visually observe the liquid level in real time. Existing oil level monitoring relies primarily on manual measurement, which not only hinders real-time monitoring but also easily leads to spills during refueling.

[0003] Traditional liquid level detection devices typically rely on pressure sensing, using pressure differences at different locations to determine liquid level. However, these devices are often bulky and expensive, making them difficult to fit into confined spaces. Furthermore, pressure detection devices require high liquid level resolution, and their complex structure limits their application in cable detection systems.

[0004] To meet the needs of liquid level detection in confined spaces, Chinese patent CN102628706A discloses a segmented liquid level measurement module that implements segmented liquid level detection through temperature feedback signals from multiple probes. Specifically, each probe includes a heating element and a temperature detection circuit. Because the specific heat capacity of liquid is much greater than that of air, under the same heating conditions, the probe immersed in liquid heats up more slowly, while the probe in air heats up more quickly. By detecting the temperature change of the probe (the higher the temperature rise, the greater the feedback voltage), the medium in which the probe is located can be determined, thereby determining the liquid level and implementing segmented liquid level measurement.

[0005] However, this technology has some drawbacks. First, the heating element, which heats the entire probe head, is relatively slow due to the distance between the heating resistor and the thermistor. Furthermore, this technology primarily determines the liquid level by measuring the total temperature change before and after heating, resulting in a larger detection unit and slower detection speed. Summary of the Invention

[0006] The present application provides a liquid level detection device. The liquid level detection device according to the present application can overcome at least one or more problems existing in the prior art.

[0007] In a first aspect of the present application, a liquid level detection device is provided for monitoring the liquid level in a narrow space, at least for monitoring the liquid level of insulating oil in the square barrel of a cable deflectometer. The liquid level detection device includes a substrate, a processor unit, a detection unit and a reference assembly. Several detection units are distributed along the length direction of the substrate. The reference assembly is connected to the processor unit through a voltage divider circuit, wherein the detection unit includes a heating element and a detection element. The heating element is connected to the heating control end of the processor unit through a switch control circuit, and the processor unit controls the on and off of the switch circuit; the detection element is electrically connected to the signal input end of the processor unit for transmitting the detected temperature signal.

[0008] In one possible implementation, the heating element rests against the detection element.

[0009] In a possible implementation, the heating element is a heating resistor, the detection element is a temperature-sensitive resistor, and the reference component is a reference resistor.

[0010] In one possible implementation, one end of a heating resistor is connected to a power supply, and the other end is connected to ground through a MOSFET, and a microprocessor in the processor unit controls the switching state of the MOSFET; the temperature-sensitive resistor and the reference resistor are connected in series to form a voltage divider circuit, and the output end of the voltage divider circuit is connected to the ADC channel of the microprocessor in the processor unit.

[0011] In one possible implementation, the multiple reference resistors are arranged on the upper portion of the substrate.

[0012] In one possible implementation, the temperature-sensitive resistor rests on the heating resistor.

[0013] In a possible implementation, the substrate is a circuit board, and a cable sealing joint is provided above the circuit board.

[0014] In one possible implementation, the circuit board and the components thereon are entirely coated with an insulating coating.

[0015] Compared with the existing technology, the present invention has the following beneficial effects: the heating element is against the detection element, and the thermistor is against the top of the heating resistor. There is no need to set a threshold database, and the liquid level can be judged only by comparing the temperature change values ​​of thermistors at different positions; the thermistor is directly heated, and the heat is taken away by the thermal conductivity effect of the medium, so as to achieve a rapid response to temperature changes, thereby shortening the detection cycle; the detection unit only contains a heating resistor and a thermistor, and the reference resistors in the peripheral circuits of multiple thermistors are concentrated on the upper part of the substrate, reducing the structural width of the middle and lower parts of the substrate to adapt to liquid level detection in a narrow space.

[0016] In a second aspect of the present application, a container device is provided, which includes a square barrel and the above-mentioned liquid level detection device.

[0017] In one possible implementation, the square barrel is a sealed container for containing insulating oil, and the liquid level detection device is arranged along the extension direction of the square barrel, installed on the upper part of the square barrel and extending into the interior thereof.

[0018] In one possible implementation, the square barrel is also provided with a spring copper tube and a high-voltage metal sleeve:

[0019] Spring copper tube: located at the top of the square barrel, with one water inlet and one water outlet located outside the barrel. The middle part is a spiral tube, through which water flows to cool and remove the oil temperature.

[0020] High-voltage metal casing: It is installed on the upper part of the square barrel and extends inward to the X-ray tube assembly. A high-voltage wire is inserted in the center to protect the high-voltage wire isolation insulating oil.

[0021] According to a third aspect of the present application, a cable deflectometer is provided, which includes the above-mentioned container device.

[0022] It should be noted that various possible implementations of any of the above aspects can be combined under the premise that the solutions are not contradictory. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a structural schematic diagram of a container device provided in an embodiment of the present application.

[0024] Figure 2 It is a structural schematic diagram of a liquid level detection device provided in an embodiment of the present application.

[0025] Figure 3 yes Figure 2 Circuit schematic diagram of the detection unit and reference component.

[0026] Figure 4 yes Figure 2 Circuit schematic diagram of the processor unit.

[0027] Figure 5 This is a circuit schematic diagram of an RS485 communication module used in a liquid level detection device provided in an embodiment of the present application.

[0028] Figure 6 This is a workflow diagram of liquid level detection of a liquid level detection device provided in an embodiment of the present application.

[0029] Description of reference numerals:

[0030] 100. Liquid level detection device; 10. Baseboard; 20. Processor unit; 30. Detection unit; 31. Heating element; 32. Detection element; 40. Reference assembly; 101. Cable sealing head; 200. Container equipment; 50. Square barrel; 51. Spring copper tube; 52. High-voltage metal casing; 53. X-ray tube. DETAILED DESCRIPTION

[0031] The present application will be described below with reference to the accompanying drawings, which illustrate several embodiments of the present application. However, it should be understood that the present application can be presented in many different ways and is not limited to the embodiments described below; in fact, the embodiments described below are intended to make the disclosure of the present application more complete and fully illustrate the scope of protection of the present application to those skilled in the art. It should also be understood that the embodiments disclosed herein can be combined in various ways to provide many additional embodiments.

[0032] It should be understood that throughout the drawings, like reference numerals represent like elements. In the drawings, the dimensions of certain features may be distorted for clarity. The terms used in this specification are intended only to describe specific embodiments and are not intended to limit this application. All terms (including technical and scientific terms) used in this specification have the meanings commonly understood by those skilled in the art, unless otherwise defined. For the sake of brevity and / or clarity, well-known functions or structures may not be described in detail.

[0033] In the first aspect, the embodiment of the present application provides a liquid level detection device 100 for solving the problem of liquid level monitoring in a narrow space, and realizes liquid level measurement through the temperature feedback signal of multiple segmented detection units 30. Figures 2 to 5 , respectively show the structure and circuit principle diagram of the liquid level detection device 100.

[0034] The liquid level detection device 100 includes a substrate 10, a processor unit 20, a detection unit 30 and a reference component 40. Several detection units 30 are distributed along the length direction of the substrate 10. The microprocessor in the processor unit 20 is responsible for controlling the heating and temperature acquisition of the detection units 30. The reference component 40 is connected to the processor unit 20 via a voltage divider circuit. The specific number of detection units 30 can be flexibly adjusted according to detection requirements.

[0035] Each detection unit 30 includes a heating element 31 and a detection element 32. The heating element 31 and the detection element 32 can be encapsulated in an insulating, thermally conductive solid adhesive to ensure good thermal conductivity and avoid the influence of liquid conductivity. In this embodiment, the liquid level detection device 100 is placed in insulating oil and is not encapsulated using an insulating, thermally conductive solid adhesive.

[0036] The heating element 31 is connected to the heating control terminal of the processor unit 20 through a switch control circuit. The processor unit 20 controls the on and off of the switch circuit, thereby controlling the operation of the heating element 31 .

[0037] The detection element 32 is electrically connected to the signal input terminal of the processor unit 20 for transmitting the detected temperature signal, which is analyzed by the processor unit 20 and used to determine the liquid level status.

[0038] In order to further reduce the volume of the detection unit 30 , only the heating element 31 (heating resistor) and the detection element 32 (temperature-sensitive resistor) are retained in the detection unit 30 , and the peripheral circuits of the heating resistor and the temperature-sensitive resistor are arranged outside the detection unit 30 .

[0039] Taking a detection unit 30 as an example, the microprocessor in the processor unit 20 controls a MOSFET (e.g., Q1) to turn a heating resistor (e.g., R4) on and off. When the heating resistor is operating, the temperature of the thermistor rises. After a certain heating period, the microprocessor turns off the heating resistor and uses the analog-to-digital conversion function to obtain the voltage across the thermistor (e.g., R11). Combined with the known resistance of reference resistor R7, the current resistance of the thermistor is calculated using a voltage divider formula, and the temperature is then inferred based on the temperature characteristics of the thermistor.

[0040] Based on the principle of circuit voltage division, the voltage ratio between a known resistor and the resistance to be measured can be used to calculate the resistance to be measured. The known resistor is R7, and the resistance to be measured is the temperature-sensitive resistor R11. The two are connected in series, and the voltage across R11 is measured.

[0041] Processor unit 20 (main control chip U1): The processor unit 20 is connected to each detection unit 30 via multiple pins (e.g., PA4, PA5, and PA6). Each pin is connected to a temperature-sensitive resistor in a detection unit 30 to obtain temperature signals at different locations. The processor unit 20 uses analog-to-digital conversion (ADC) to read the voltage signal from the temperature-sensitive resistor to calculate the temperature.

[0042] Detection unit 30: Each detection unit 30 includes a heating resistor (e.g., R1, R2, R3) and a temperature-sensitive resistor (e.g., R11, R13, R15). The heating resistor is connected to power supply VIN via MOSFETs (e.g., Q1, Q2, Q3). The processor unit 20 controls the heating on and off, thereby heating the detection element 32. The temperature-sensitive resistor detects temperature changes and outputs a temperature signal through a voltage divider of the reference component 40.

[0043] Reference component 40: This component consists of a reference resistor (e.g., R7, R8, R9) connected in series with a temperature-sensitive resistor (e.g., R11, R13, R15) to form a voltage divider circuit. The output of the voltage divider circuit is connected to the ADC channels of the processing unit (e.g., ADC4_NTC, ADC5_NTC, ADC6_NTC). Reference component 40 provides a stable reference voltage, enabling the processing unit 20 to accurately measure the voltage change across the temperature-sensitive resistor and thus determine temperature changes.

[0044] Calculating thermistor resistance

[0045] 1. Determine the total voltage of the circuit , for example 3.3V.

[0046] 2. The microprocessor in the processor unit 20 reads the Voltage across both ends .

[0047] 3. Calculate the temperature sensitive resistor according to the voltage divider formula Resistance value:

[0048]

[0049] Calculate temperature based on thermistor characteristics

[0050] Different thermistors have corresponding temperature-resistance relationship curves, and the temperature can be calculated using the temperature characteristic formula.

[0051] The temperature calculation formula is ,in Indicates temperature, Indicates the resistance of the temperature sensitive resistor.

[0052] use Substituting the resistance value into the formula, we can get the temperature .

[0053] like Figure 6 As shown, the workflow is as follows:

[0054] Step 1: Start: Start the process;

[0055] Step 2: The heating resistor starts working: start the heating resistor and start heating;

[0056] Step 3: Wait for n seconds: Wait for a preset time to ensure that the heating resistor heats the temperature sensitive resistor sufficiently;

[0057] Step 4: Turn off the heating resistor, detect the current temperature of each liquid point and record it: stop heating, collect the temperature value of the current temperature-sensitive resistor in each detection unit 30, and record it;

[0058] Step 5: Wait for n seconds: Wait again for a while to allow the temperature to drop naturally. The heat on the thermistor diffuses in the liquid or air. The liquid dissipates heat faster because its thermal conductivity is higher than that of air.

[0059] Step 6: Detect the current temperature of each liquid point and make a difference with the last recorded value: re-measure the temperature of the temperature-sensitive resistor in each detection unit 30 and compare it with the last recorded temperature value;

[0060] Step 7: Determine whether the temperature difference exceeds the threshold: Check whether the temperature difference exceeds the preset threshold (which can be 1 value), or compare the temperature differences with each other:

[0061] If the threshold is exceeded: the detection point is judged to be immersed in oil;

[0062] If the threshold is not exceeded: the detection point is judged to be in the air;

[0063] Step 8: Count all detection points to obtain the current liquid level position: Count the status of each detection unit 30 to determine the current liquid level height;

[0064] Step 9: Send the liquid level and oil temperature information via RS485: Send the detected liquid level position and oil temperature information via the RS485 bus.

[0065] Liquid level detection data can be remotely transmitted via the RS485 communication module, enabling remote monitoring. This device not only offers high detection accuracy and fast response, but is also adaptable to liquid level measurement needs in confined spaces. The number of probes can be flexibly increased or decreased to meet diverse applications.

[0066] In the prior art, Chinese patent CN102628706A discloses a segmented liquid level measurement module that implements segmented liquid level detection through temperature feedback signals from multiple probes. Specifically, each probe in this solution includes a heating element and a temperature detection circuit. Because the specific heat capacity of liquid is much higher than that of air, under the same heating conditions, the probe immersed in the liquid heats up more slowly, while the probe exposed to the air heats up more quickly. By detecting the temperature difference between the probe before heating and the temperature after heating for a period of time, the medium in which the probe is located can be determined, thereby determining the liquid level height and realizing segmented liquid level measurement.

[0067] In this technical solution, the heating element and the temperature detection circuit need to be kept apart so that the temperature detection circuit in the liquid medium can heat up slowly after being heated for a period of time. The detection head of this technical solution is large in size and slow in detection speed, and a threshold library comparison needs to be set in advance.

[0068] In this application, the heating element 31 rests on the detection element 32, and the thermistor rests on top of the heating resistor. There is no need to set a threshold library, and the liquid level can be determined by simply comparing the temperature change values ​​of thermistors at different positions; the thermistor is directly heated, and the heat is taken away through the thermal conductivity effect of the medium, achieving a rapid response to temperature changes, thereby shortening the detection cycle.

[0069] The reference resistors in the peripheral circuits of the multiple temperature-sensitive resistors are centrally arranged on the upper portion of the substrate 10 so as to reduce the structural width of the lower portion of the substrate 10 .

[0070] The substrate 10 is a circuit board, and a cable sealing joint is provided above the circuit board.

[0071] Second, as Figure 1 As shown, an embodiment of the present application provides a container device 200, including a square barrel 50 and a liquid level detection device 100. The square barrel 50 is a sealed container for containing insulating oil, and the liquid level detection device 100 is arranged along the extension direction of the square barrel 50, installed on the upper part of the square barrel 50 and extending into the interior thereof.

[0072] The square barrel 50 is equipped with an X-ray tube 53, which is a device capable of generating X-rays. The X-ray tube 53 generates rays by high-speed electron collision with a target material. After the rays penetrate the material, the internal structure of the object can be imaged or detected based on the degree of absorption and scattering in different materials. The principle of this technology is similar to X-ray imaging, which analyzes the absorption differences of materials with different densities. In the cable detection device, the X-ray tube 53 is mainly used for non-destructive testing of the internal structure of the cable. The rays can penetrate the insulation layer and conductor of the cable and measure the wall thickness, eccentricity, diameter and ovality of multi-layer or single-layer cross-linked cables. X-ray detection can provide accurate internal images or data to help determine whether the cable has hidden dangers, thereby ensuring the reliability and safety of the cable.

[0073] The X-ray tube 53 generates a significant amount of heat during operation. Insulating oil helps dissipate heat from the X-ray tube 53, preventing damage from overheating. Insulating oil has excellent thermal conductivity, quickly dissipating the heat generated by the X-ray tube 53 during operation, keeping it operating within a suitable temperature range and extending its service life.

[0074] The square barrel 50 is also provided with a spring copper tube 51 and a high-voltage metal sleeve 52:

[0075] Spring copper tube 51: Located at the top of the square barrel 50, with one water inlet and one water outlet located outside the barrel 50. The middle part is a spiral tube, through which water flows to cool the oil.

[0076] High-voltage metal casing 52: It is set at the upper part of the square barrel 50 and extends inward to the X-ray tube 53 assembly. A high-voltage wire is inserted in the center to protect the high-voltage wire isolation insulating oil.

[0077] Thirdly, the container device 200, installed on a cable deflectometer, is primarily used for nondestructive testing of cables, helping to verify the integrity and quality of the cable's internal structure. The radiation emitted by the X-ray tube 53 can penetrate the cable's insulation and conductors, measuring the wall thickness, eccentricity, diameter, and ovality of multi-layer or single-layer cross-linked cables, providing precise internal images or data. Combined with the liquid level detection device 100 and the cooling system (spring copper tube 51 and insulating oil), the container device 200 ensures the X-ray tube 53 operates at an appropriate temperature and isolates high-voltage lines for enhanced safety. This device effectively improves the reliability and safety of cable testing, thereby preventing potential cable failures during operation.

[0078] Although exemplary embodiments of the present application have been described, it will be understood by those skilled in the art that various changes and modifications may be made to the exemplary embodiments of the present application without departing substantially from the spirit and scope of the present application. Therefore, all such changes and modifications are intended to be within the scope of protection of the present application as defined by the appended claims. The present application is defined by the appended claims, and equivalents of these claims are intended to be included therein.

Claims

1. A liquid level detection device for monitoring the liquid level in a narrow space, the liquid level detection device (100) comprising a substrate (10), a processor unit (20), a detection unit (30) and a reference assembly (40), wherein a plurality of detection units (30) are distributed along the length direction of the substrate (10), and the reference assembly (40) is connected to the processor unit (20) via a voltage divider circuit, characterized in that: The detection unit (30) comprises a heating element (31) and a detection element (32); the heating element (31) is connected to a heating control terminal of the processor unit (20) via a switch control circuit, and the processor unit (20) controls the on and off of the switch circuit; and the detection element (32) is electrically connected to a signal input terminal of the processor unit (20).

2. The liquid level detection device according to claim 1, characterized in that: The heating element (31) rests on the detection element (32).

3. The liquid level detection device according to claim 2, characterized in that: The heating element (31) is a heating resistor, the detection element (32) is a temperature-sensitive resistor, and the reference component (40) is a reference resistor.

4. The liquid level detection device according to claim 3, characterized in that: One end of the heating resistor is connected to a power supply, and the other end is connected to ground via a MOSFET, and the microprocessor in the processor unit (20) controls the switching state of the MOSFET; the temperature-sensitive resistor and the reference resistor are connected in series to form a voltage divider circuit, and the output end of the voltage divider circuit is connected to an ADC channel of the microprocessor in the processor unit (20).

5. The liquid level detection device according to claim 4, characterized in that: The plurality of reference resistors are arranged on the upper portion of the substrate (10).

6. The liquid level detection device according to claim 3, characterized in that: The temperature-sensitive resistor is placed on top of the heating resistor.

7. The liquid level detection device according to claim 5, characterized in that: The substrate (10) is a circuit board, and a cable sealing joint is provided above the circuit board.

8. The liquid level detection device according to claim 7, characterized in that: The circuit board and the components thereon are entirely coated with an insulating coating.

9. A container device, characterized in that: The container device (200) comprises a square barrel (50) and a liquid level detection device (100) according to any one of claims 1 to 8.

10. A cable deflectometer, characterized in that: The cable deflectometer comprises a container device (200) according to claim 9.

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