A continuous strip temperature resistance liquid level sensor and liquid level measurement method

Abstract

This invention relates to the field of liquid level sensor technology, and provides a continuous strip temperature resistance liquid level sensor and a liquid level measurement method. The continuous strip temperature resistance liquid level sensor includes a body, a heating component, a temperature measuring component, and a control module. The body is adapted to be arranged along the height direction of the container. The heating component is located inside the body for heating the body. The temperature measuring component is located inside the body and includes multiple detection groups arranged at intervals along the length direction of the body. Each detection group includes a heated unit and a reference unit at the same height position. The thermal resistance between the heated unit and the heating component is less than the thermal resistance between the reference unit and the heating component. The control module is electrically connected to the heating component and the temperature measuring component respectively. The control module is configured to calculate the temperature difference between the heated unit and the reference unit in the same detection group, and determine the liquid level height according to the distribution law of the temperature difference values ​​corresponding to each detection group.

Description

Technical Field

[0001] This invention relates to the field of liquid level sensor technology, and in particular to a continuous strip temperature resistance liquid level sensor and a liquid level measurement method. Background Technology

[0002] In related technologies, capacitive, conductive, or radio frequency admittance level sensors all rely heavily on the electrical properties (such as dielectric constant or conductivity) of the measured medium as their core operating principle. However, when the measured medium has a complex composition, contains foam, has wall contamination, or its electrical properties fluctuate drastically with temperature / concentration, the measurement reference of these sensors will drift, making it impossible to accurately distinguish the gas-liquid interface, resulting in serious measurement errors or even failure. Summary of the Invention

[0003] This invention provides a continuous strip temperature resistance liquid level sensor to solve the defects in related technologies that rely on the electrical properties of the medium, resulting in measurement reference drift and decreased accuracy under conditions of foam, high viscosity, or composition fluctuation. It realizes continuous liquid level detection with high stability and high adaptability based on the thermal principle of the difference in heat dissipation coefficients between gas and liquid phases.

[0004] The present invention also provides a liquid level measurement method.

[0005] This invention provides a continuous strip-shaped temperature resistance liquid level sensor, comprising: The main body is designed to be arranged along the height of the container; A heating component, disposed within the body, is used to heat the body. A temperature measuring component is disposed within the body. The temperature measuring component includes multiple detection groups arranged at intervals along the length direction of the body. Each detection group includes a heating unit and a reference unit at the same height position. The thermal resistance between the heating unit and the heating component is less than the thermal resistance between the reference unit and the heating component. The control module is electrically connected to both the heating component and the temperature measuring component. The control module is configured to calculate the temperature difference between the heated unit and the reference unit in the same detection group, and determine the liquid level height based on the distribution pattern of the temperature difference values ​​corresponding to each detection group.

[0006] In some embodiments, the heating unit is attached to the heating assembly, and an insulation layer is provided between the reference unit and the heating assembly; Alternatively, the distance between the reference unit and the heating component is greater than the distance between the heated unit and the heating component.

[0007] In some embodiments, the heating assembly includes: Multiple serpentine resistor strips are spaced apart along the length of the body.

[0008] In some embodiments, the body includes: The heating zone and two detection zones are located in the width direction of the body. The heating zone is located between the two detection zones, the heating assembly is located in the heating zone, and the heating unit and the reference unit are respectively located in the two detection zones. The protective zone is located on the side of the detection zone away from the heating zone.

[0009] In some embodiments, the body comprises the following components arranged sequentially along its thickness direction: A reinforcing layer is used to improve the rigidity of the body. The base layer serves as the supporting carrier for the main body; A heating resistance layer is provided with the aforementioned heating component; An insulating layer is used to achieve electrical isolation; The temperature resistance sensing layer is equipped with the temperature measuring component.

[0010] In some embodiments, the body includes: A back insulating layer is provided on the outside of the reinforcing layer; A surface insulating and thermally conductive layer is disposed on the outside of the temperature resistance detection layer.

[0011] In some embodiments, the body includes: An outer protective layer is disposed outside the surface insulating and thermally conductive layer, and the outer protective layer is made of one or more of FEP, PFA, PTFE or ETFE materials.

[0012] In some embodiments, the reinforcing layer is provided with: Multiple grooves are arranged at intervals along the length of the body, and each groove extends along the width of the body.

[0013] In some embodiments, the continuous strip temperature resistance liquid level sensor includes: A counterweight assembly is located at the bottom of the body, and the counterweight assembly is used to keep the body taut when it is suspended; And / or, a protective sleeve, wherein the body is detachably disposed within the protective sleeve.

[0014] An embodiment of the present invention discloses a liquid level measurement method, comprising: S1. Drive the heating assembly to heat the body to form a temperature field along the length of the body; S2. Collect temperature detection signals from multiple detection groups at different height positions; S3. Construct a temperature difference distribution curve along the length direction of the body based on the temperature detection signal; S4. Determine the liquid level height based on the location of the abrupt change point or gradient change in the temperature difference distribution curve.

[0015] The continuous strip temperature resistance liquid level sensor of this invention measures the liquid level by utilizing the physical difference in heat dissipation capacity between liquid and gas, rather than relying on dielectric constant or conductivity. Therefore, it can maintain the stability of the measurement reference even when the composition of the measured medium is complex or the electrical properties fluctuate, thus avoiding measurement failure caused by changes in medium properties.

[0016] The continuous strip temperature resistance liquid level sensor of this invention effectively counteracts the effects of common-mode interference factors such as changes in ambient temperature and fluctuations in the overall temperature of the medium by setting heated units and reference units with different thermal resistances at the same height and calculating the temperature difference between them. This differential detection method enables the system to accurately identify the temperature distribution pattern at the gas-liquid interface even under conditions of wall contamination or foam interference, thus improving the reliability of liquid level detection. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the structure of the continuous strip temperature resistance liquid level sensor of the present invention.

[0019] Figure 2 This is a schematic diagram of a first embodiment of the body of the continuous strip temperature resistance liquid level sensor of the present invention.

[0020] Figure 3 This is a schematic diagram of a second embodiment of the body of the continuous strip temperature resistance liquid level sensor of the present invention.

[0021] Figure 4 This is a schematic diagram of the control module of the continuous strip temperature resistance liquid level sensor of the present invention.

[0022] Figure 5 The temperature difference distribution curve is obtained using the continuous strip temperature resistance liquid level sensor of the present invention.

[0023] Figure 6 This is a schematic diagram of the installation of the continuous strip temperature resistance liquid level sensor of the present invention using a top-suspended method.

[0024] Figure 7 This is a schematic diagram of the continuous strip temperature resistance liquid level sensor of the present invention installed using a wall-mounted method.

[0025] Figure 8 This is a schematic diagram of the installation of the continuous strip temperature resistance liquid level sensor of the present invention using a protective sleeve.

[0026] Figure label: 100. Continuous strip temperature resistance liquid level sensor; 200. Container; 201. Liquid level; 202. Liquid medium; 203. Gas phase space; 1. Body; 11. Outer protective layer; 12. Surface insulating and thermally conductive layer; 13. Temperature resistance detection layer; 130. Temperature sensing component; 131. Detection group; 132. Heat-sensitive detection array; 133. Reference detection array; 14. Insulating layer; 15. Heating resistance layer; 150. Heating assembly; 151. Serpentine resistance strip; 16. Base layer; 17. Reinforcing layer; 18. Back insulation layer; 19. Electrical connection terminals; 20. Top sealing area; 30. Control module; 31. Constant current source; 32. Multiplexing circuit; 33. Signal conditioning circuit; 34. Analog-to-digital converter circuit; 35. Microcontroller; 36. Heating drive circuit; 37. Communication output circuit; 40. Counterweight components; 50. Protective sleeve; 61. Mounting rail; 62. Clip-on connector. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0028] The following is combined with Figures 1 to 8 The present invention describes a continuous strip temperature resistance liquid level sensor 100.

[0029] like Figure 1 As shown, the continuous strip temperature resistance liquid level sensor 100 of this embodiment includes a body 1, a heating component 150, a temperature measuring component 130, and a control module 30.

[0030] The main body 1 is suitable for being arranged along the height direction of the container 200. The liquid medium 202 is below the liquid level 201, and the gas phase space 203 is above the liquid level 201.

[0031] The heating component 150 is located inside the body 1 and is used to heat the body 1.

[0032] The temperature measuring component 130 is disposed inside the body 1. The temperature measuring component 130 includes multiple detection groups 131 arranged at intervals along the length direction of the body 1. Each detection group 131 includes a heated unit and a reference unit at the same height position. The thermal resistance between the heated unit and the heating component 150 is less than the thermal resistance between the reference unit and the heating component 150.

[0033] The control module 30 is electrically connected to the heating component 150 and the temperature measuring component 130, respectively.

[0034] The control module 30 is configured to calculate the temperature difference between the heated unit and the reference unit in the same detection group 131, and determine the liquid level height based on the distribution pattern of the temperature difference values ​​corresponding to each detection group 131.

[0035] For ease of description, the technical solution of this application will be described below with the length direction of the body 1 as the up and down direction, where the up and down direction is as follows: Figure 1 As shown.

[0036] Multiple heated units form a heated detection array 132; multiple reference units form a reference detection array 133.

[0037] When the continuous strip temperature resistance liquid level sensor 100 is in operation, the control module 30 first drives the heating component 150 to heat the body 1. Due to the difference in heat dissipation capacity between the liquid medium 202 and the gas phase space 203 in the container 200, the part of the body 1 immersed in the liquid dissipates heat faster, while the part exposed to the gas dissipates heat slower, thus forming a specific temperature distribution along the length of the body 1. Subsequently, multiple detection groups 131 in the temperature sensing component 130 work synchronously to collect temperature data of the heated unit and the reference unit at each height position. The control module 30 calculates the temperature difference between the heated unit and the reference unit in the same detection group 131 to eliminate common-mode interference. Finally, the control module 30 constructs a temperature difference distribution curve based on each temperature difference value and determines the liquid level height based on at least one of the following characteristics: the location of the maximum value of the first-order gradient, the inflection point, or the threshold transition zone of the temperature difference distribution curve.

[0038] In related technologies, capacitive, conductive, or radio frequency admittance level sensors all rely heavily on the electrical properties (such as dielectric constant or conductivity) of the measured medium as their core operating principle. However, when the measured medium has a complex composition, contains foam, has wall contamination, or its electrical properties fluctuate drastically with temperature / concentration, the measurement reference of these sensors will drift, making it impossible to accurately distinguish the gas-liquid interface, resulting in serious measurement errors or even failure.

[0039] The continuous strip temperature resistance liquid level sensor 100 of this invention measures the liquid level by utilizing the physical difference in heat dissipation capacity between liquid and gas, rather than relying on dielectric constant or conductivity. Therefore, it can maintain the stability of the measurement reference even when the composition of the measured medium is complex or the electrical properties fluctuate, thus avoiding measurement failure caused by changes in medium properties.

[0040] The continuous strip temperature resistance liquid level sensor 100 of this invention effectively counteracts the influence of common-mode interference factors such as changes in ambient temperature and fluctuations in the overall temperature of the medium by setting heating units and reference units with different thermal resistances at the same height and calculating the temperature difference between them. This differential detection method enables the system to accurately identify the temperature distribution pattern at the gas-liquid interface even under conditions of wall contamination or foam interference, thus improving the reliability of liquid level detection.

[0041] Therefore, the continuous strip temperature resistance liquid level sensor 100 of the present invention can reduce dependence on the electrical properties of the dielectric and has strong anti-interference ability.

[0042] The thermal coupling between the heated unit and the heating component 150 is strong, while the thermal coupling between the reference unit and the heating component 150 is weak.

[0043] In some embodiments, the heating unit is attached to the heating assembly 150, and an insulation layer is provided between the reference unit and the heating assembly 150.

[0044] In some embodiments, the distance between the reference unit and the heating component 150 is greater than the distance between the heated unit and the heating component 150.

[0045] In this embodiment, differentiated thermal coupling is achieved by adjusting the spatial arrangement of the internal units of the temperature sensing component 130 and the heat source. For example, the heated unit is directly attached to the surface of the heating component 150 or very close to it to receive heat quickly and fully; while the reference unit is thermally resisted by adding an insulation layer or by increasing its physical distance from the heating component 150, thus receiving less heat. This structural arrangement allows two units at the same height to exhibit different base temperature states under the same heating conditions.

[0046] The continuous strip temperature resistance liquid level sensor 100 of this invention constructs a heated unit and a reference unit with different thermal resistance paths, and utilizes the difference in their responses to the same heat source to form a stable temperature difference reference. This design allows liquid level detection to no longer rely on a single absolute temperature value, but rather to be based on temperature difference, effectively filtering out common-mode interference caused by ambient temperature fluctuations or overall temperature changes of the medium, thereby improving the accuracy and stability of liquid level identification.

[0047] In some embodiments, such as Figure 3As shown, the heating assembly 150 includes a plurality of serpentine resistance strips 151, which are spaced apart along the length of the body 1.

[0048] In this embodiment, the heating component 150 does not use a single straight resistor, but is composed of multiple serpentine resistor strips 151. The serpentine resistor strips 151 are resistor strips that bend back and forth, and these serpentine resistor strips 151 are arranged alternately along the vertical direction. The serpentine routing increases the coverage area of ​​the resistor strips in the local area, while the spacing helps to balance the heat distribution along the length of the body 1, avoiding local overheating or heating blind spots.

[0049] The continuous strip temperature resistance liquid level sensor 100 of this invention adopts a serpentine resistance strip 151 structure with intervals, which can form a uniform or nearly uniform temperature field in the length direction of the body 1, avoiding temperature curve distortion caused by uneven heating, so as to accurately determine the liquid level through temperature gradient.

[0050] In some embodiments, such as Figure 3 As shown, the main body 1 includes a heating zone, two detection zones, and a protective zone. The two detection zones are located along the width of the main body 1. The heating zone is situated between the two detection zones, and a heating assembly 150 is located within the heating zone. A heated unit and a reference unit are respectively located within the two detection zones. The protective zone is located on the side of the detection zones opposite to the heating zone.

[0051] For ease of description, the technical solution of this application will be described below with the left and right directions as the width direction of the body 1. The left and right directions are as follows: Figure 1 As shown.

[0052] In this embodiment, the body 1 is divided into three functionally distinct areas in a planar layout: a heating area in the middle for arranging the heating component 150, detection areas on both sides of the heating area for arranging the temperature measuring components 130, and an outermost protective area. This planar arrangement allows the heat generated by the heating area to diffuse to the detection areas on both sides, while the outer protective area provides mechanical protection and edge isolation for the internal functional circuitry. By arranging the heated unit and the reference unit, the thermal coupling between the heated unit and the heating component 150 is strong, while the thermal coupling between the reference unit and the heating component 150 is weak. For example, the distance h between the heated unit and the heating component 150 is equal to the distance H between the reference unit and the heating component 150, where h < H.

[0053] The continuous strip temperature resistance liquid level sensor 100 of this invention optimizes the heat conduction path by placing the heating zone between two detection zones, enabling the detection zones on both sides to quickly acquire heat, which is beneficial for subsequent detection. Simultaneously, the outer protective zone enhances the structural strength of the body 1's edges, preventing damage to the internal sensitive detection circuitry due to edge stress during installation or use, thus improving the overall durability of the continuous strip temperature resistance liquid level sensor 100.

[0054] In some embodiments, such as Figure 2 As shown, the body 1 includes a reinforcing layer 17, a base layer 16, a heating resistance layer 15, an insulating layer 14, and a temperature resistance detection layer 13 arranged sequentially along its thickness direction.

[0055] The reinforcing layer 17 is used to improve the rigidity of the body 1. The base layer 16 serves as the supporting carrier for the body 1. The heating resistance layer 15 is equipped with a heating assembly 150. The insulating isolation layer 14 is used to achieve electrical isolation. The temperature resistance sensing layer 13 is equipped with a temperature sensing assembly 130.

[0056] In this embodiment, the body 1 adopts a multi-layer composite structure, with each functional layer stacked along the thickness direction. The base layer 16 serves as the core support, supporting the heating resistance layer 15 and the temperature resistance detection layer 13 above it; the insulating isolation layer 14 is sandwiched between the heating resistance layer 15 and the temperature resistance detection layer 13 to ensure electrical safety and regulate heat transfer efficiency; the reinforcing layer 17 serves as a backing, providing the necessary longitudinal stiffness to prevent the flexible strip from bending or deforming excessively. If the continuous strip-shaped temperature resistance liquid level sensor 100 is installed in the container 200 in a wall-mounted manner, the reinforcing layer 17 is positioned closer to the wall of the container 200 than the temperature resistance detection layer 13.

[0057] The continuous strip temperature resistance liquid level sensor 100 of this invention integrates heating, detection, insulation, and reinforcement functions within a limited thickness space through a multi-layer composite structure. The introduction of the reinforcing layer 17 solves the problem of curling or swaying that easily occurs when the continuous strip temperature resistance liquid level sensor 100 is suspended, ensuring the vertical posture of the continuous strip temperature resistance liquid level sensor 100 in the container 200; at the same time, the insulating isolation layer 14 achieves safe isolation between the high-pressure heating circuit and the low-pressure detection circuit in a compact space, taking into account both structural compactness and operational safety.

[0058] In some embodiments, the body 1 includes a back insulating layer 18 and a surface insulating thermally conductive layer 12. The back insulating layer 18 is disposed outside the reinforcing layer 17. The surface insulating thermally conductive layer 12 is disposed outside the temperature resistance sensing layer 13.

[0059] In this embodiment, a back insulation layer 18 is provided on the side of the body 1 away from the medium being measured (back side), which further seals the reinforcing layer 17 and provides additional electrical insulation protection; a surface insulation and thermally conductive layer 12 is provided on the side of the body 1 facing the medium being measured (surface), which covers the temperature resistance detection layer 13 and serves both as electrical insulation and as having good thermal conductivity, so that the temperature change of the medium being measured can be quickly transmitted to the temperature measuring component 130.

[0060] The continuous strip temperature resistance liquid level sensor 100 of this invention features a surface insulating and thermally conductive layer 12 that optimizes the heat exchange efficiency between the sensor and the medium, shortens the temperature response time, and enables the detection results to reflect liquid level changes more in real time. Simultaneously, the double-sided insulating layer design constructs a complete electrical protection system, preventing external liquid infiltration that could cause short circuits and preventing internal electrical signal leakage, thus meeting the requirements for long-term stable operation in humid or conductive liquid environments.

[0061] In some embodiments, the body 1 includes an outer protective layer 11, which is disposed outside the surface insulating and thermally conductive layer 12. The outer protective layer 11 is made of one or more of FEP, PFA, PTFE or ETFE materials.

[0062] In this embodiment, an outer protective layer 11 made of fluoroplastics (such as FEP, PFA, PTFE or ETFE) is wrapped around the outer side of the surface insulating and thermally conductive layer 12 of the body 1. These materials have excellent chemical inertness, corrosion resistance and low surface energy properties, and come into direct contact with the liquid being tested, forming a robust physical and chemical barrier.

[0063] The continuous strip temperature resistance liquid level sensor 100 of this invention uses a fluorinated polymer material as the outer protective layer 11, which endows the continuous strip temperature resistance liquid level sensor 100 with extremely strong resistance to acid and alkali corrosion and anti-pollution capabilities. When dealing with highly corrosive chemical liquids or media that are prone to wall contamination, the outer protective layer 11 can effectively prevent the medium from eroding the internal functional layer, and its smooth surface reduces the residue of deposits, thereby maintaining the long-term measurement accuracy and service life of the continuous strip temperature resistance liquid level sensor 100.

[0064] In some embodiments, the reinforcing layer 17 is provided with a plurality of grooves, which are spaced apart along the length direction of the body 1 and each groove extends along the width direction of the body 1.

[0065] In this embodiment, in order to improve the longitudinal stiffness of the body 1 without sacrificing lateral flexibility, a series of grooves extending in the left-right direction are machined on the reinforcing layer 17, and these grooves are spaced apart in the vertical direction. This slotted structure cuts off the continuous metal passage in the vertical direction of the reinforcing layer 17, but retains enough material to maintain the overall tensile strength.

[0066] The continuous strip temperature resistance liquid level sensor 100 of this invention features an intermittent groove structure on the reinforcing layer 17 that effectively blocks the longitudinal conduction path of heat along the length of the body 1, reducing thermal crosstalk between adjacent detection points. This makes temperature detection at each height position more independent and accurate, avoiding ambiguity of the liquid level interface caused by longitudinal heat diffusion.

[0067] In some embodiments, the continuous strip temperature resistance liquid level sensor 100 includes a counterweight assembly 40 disposed at the bottom of the body 1, which is used to keep the body 1 taut when suspended.

[0068] In this embodiment, a counterweight assembly 40 is connected to the bottom of the main body 1. The body 1 is suspended and hangs down naturally by gravity and is kept in a vertical tension state, eliminating slack and bending. The design of the counterweight assembly 40 simplifies the installation process of long-range sensors and can achieve vertical arrangement without complicated bottom fixing. It is particularly suitable for deep tanks or containers 200 with limited top openings.

[0069] In some embodiments, such as Figure 8 As shown, the main body 1 is detachably installed inside the protective sleeve 50.

[0070] In this embodiment, the main body 1 is placed inside the protective sleeve 50, using the sleeve wall to resist external mechanical impacts, the impact of the stirring blades, or the scouring of high-speed fluids. The protective sleeve 50 expands the application scenarios of the sensor, enabling it to operate normally under harsh conditions such as high flow rates, strong stirring, or the presence of solid particle impacts, protecting the fragile internal layered structure from physical damage.

[0071] The liquid level measurement method of this invention includes: S1. Drive the heating component 150 to heat the body 1 to form a temperature field along the length of the body 1.

[0072] S2. Collect temperature detection signals from multiple detection groups 131 at different height positions.

[0073] S3. Construct a temperature difference distribution curve along the length of body 1 based on the temperature detection signal.

[0074] S4. Determine the liquid level height based on the location of abrupt change points or gradient changes in the temperature difference distribution curve.

[0075] The liquid level measurement method of this invention drives the heating component 150 to heat the body 1, so that the body 1 establishes a temperature field along the length direction.

[0076] Multiple detection groups 131 arranged at intervals along the length of the body 1 are selected sequentially, and the first temperature value T1 of the first temperature sensing unit and the second temperature value T2 of the second temperature sensing unit in each detection group 131 are collected respectively. The real-time temperature difference value ΔT=T1-T2 within the same detection group 131 is calculated.

[0077] like Figure 5 As shown, a temperature difference distribution curve is constructed along the length of body 1 with the length position of body 1 as the horizontal axis and the real-time temperature difference value as the vertical axis.

[0078] The temperature difference distribution curve is analyzed to identify the location of the maximum absolute value of the temperature gradient, the inflection point, or the abrupt transition zone exceeding the preset threshold. The height position corresponding to the above feature points is determined as the liquid level height.

[0079] Based on the measured medium type parameters, ambient temperature parameters, or historical data, the determined liquid level height is compensated and corrected, and the final liquid level value is output.

[0080] The liquid level measurement method of this invention determines the liquid level by constructing a temperature difference distribution curve and identifying its abrupt change points or gradient change locations, fundamentally avoiding the dependence of traditional technologies on the electrical parameters of the medium. This method utilizes the inherent thermophysical property differences of materials, thus enabling the acquisition of clear gas-liquid boundary characteristics even in complex media compositions, containing foam, or exhibiting conductivity fluctuations. This solves the problems of reference drift and measurement failure of traditional capacitive or conductive sensors under complex operating conditions.

[0081] Furthermore, the control module 30 can perform at least one of the following processing on the temperature data: smoothing filtering, time averaging, outlier removal, gradient calculation, hysteresis determination, and medium compensation, in order to improve the stability of liquid level identification and reduce errors caused by liquid surface fluctuations, foam, liquid residue, and wall heat conduction.

[0082] Both the heated unit and the reference unit are platinum resistance thermometers, such as Pt1000.

[0083] In some embodiments, the main body 1 is configured with a variety of installation methods to adapt to the installation requirements of different container 200 structures and field conditions.

[0084] An adhesive layer is provided on the back of the main body 1, and a high-performance adhesive is used to directly fix the continuous strip temperature resistance liquid level sensor 100 to the inner wall of the container 200. Alternatively, a suspension part is provided at the top of the main body 1, which, together with the flange or bracket at the top of the container 200, enables vertical hanging. Top-hanging installation can reduce the influence of heat conduction of the container 200 wall on the liquid level detection results, and is the preferred installation method.

[0085] Alternatively, the continuous strip temperature resistance level sensor 100 may have a mounting portion, which can be a slot, guide rail, or mounting hole, for locking the sensor in a specific position using mechanical fasteners. These structures offer flexible deployment options, allowing users to choose the most suitable fixing method based on available space.

[0086] The surface insulating thermally conductive layer 12 and the insulating isolation layer 14 are made of polyimide film.

[0087] The substrate 16 is preferably made of polyimide film.

[0088] The reinforcing layer 17 is preferably made of stainless steel strip, nickel alloy strip or glass fiber reinforced polyimide sheet.

[0089] The serpentine resistor strip 151 is made of at least one of nickel-chromium alloy, constantan, thick film resistor paste or thin film resistor material.

[0090] Optionally, the total length of the body 1 is 100mm to 3000mm, the total width is 6mm to 25mm, and the total thickness is 0.2mm to 1.2mm. The outer protective layer 11 has a thickness of 20μm to 200μm, the surface insulating and thermally conductive layer 12 has a thickness of 10μm to 100μm, the insulating isolation layer 14 has a thickness of 10μm to 80μm, the heating resistance layer 15 has a thickness of 5μm to 50μm, the base layer 16 has a thickness of 12μm to 100μm, the reinforcing layer 17 has a thickness of 30μm to 300μm, and the back insulating layer 18 has a thickness of 10μm to 100μm.

[0091] Optionally, the spacing between adjacent detection groups 131 is 2mm to 20mm, preferably 5mm to 10mm.

[0092] In some embodiments, such as Figure 4 As shown, the control module 30 includes a constant current source 31, a multiplexing circuit 32, a signal conditioning circuit 33, an analog-to-digital converter circuit 34, a microcontroller 35, a heating drive circuit 36, and a communication output circuit 37.

[0093] The heating resistance layer 15 is connected to the heating drive circuit 36 ​​via the electrical connection terminal 19 at the top of the continuous strip temperature resistance liquid level sensor 100. The heating drive circuit 36 ​​can adopt a constant voltage, constant current or constant power drive mode, and a constant power drive mode is preferred.

[0094] Multiple detection groups 131 are connected to a multiplexing circuit 32 via leads. The multiplexing circuit 32 sequentially selects each detection group 131. A constant current source 31 provides a measuring current to the selected detection group 131. A signal conditioning circuit 33 amplifies, filters, and performs a reference comparison on the acquired voltage signal. An analog-to-digital converter 34 converts the analog signal into a digital signal. A microcontroller 35 processes the digital signal and outputs the liquid level information. A communication output circuit 37 can output 4–20mA, RS485, CAN, or other standard industrial signals.

[0095] The following describes a specific embodiment of a continuous strip temperature resistance liquid level sensor 100.

[0096] The body 1 has a total length of 1000 mm, a total width of 12 mm, and a total thickness of approximately 0.5 mm. The outer protective layer 11 is made of a 75 μm thick FEP film; the surface insulating and thermally conductive layer 12 is made of a 25 μm thick polyimide film; the temperature resistance detection layer 13 includes 90 Pt1000 detection units spaced 10 mm apart along the length; the insulating isolation layer 14 is made of a 25 μm thick polyimide film; the heating resistance layer 15 is made of a 15 μm thick nickel-chromium alloy serpentine resistance strip 151; the base layer 16 is made of a 50 μm thick polyimide film; and the reinforcing layer 17 is made of a 100 μm thick 316L stainless steel strip.

[0097] The total heating power of the heating resistance layer 15 is set to 1.5W. During operation, the microcontroller 35 periodically scans the temperature values ​​of each detection group 131 and determines the liquid level height based on the location of the maximum value of the first-order gradient of the temperature distribution curve along the length. Under stable liquid level conditions, the liquid level resolution can reach 5mm to 10mm.

[0098] like Figure 4 As shown, the control module 30 includes a constant current source 31, a multiplexing circuit 32, a signal conditioning circuit 33, an analog-to-digital converter circuit 34, a microcontroller 35, a heating drive circuit 36, and a communication output circuit 37.

[0099] The heating resistance layer 15 is connected to the heating drive circuit 36 ​​via the top electrical connection terminal 19. The heating drive circuit 36 ​​can adopt a constant voltage, constant current or constant power drive mode, and a constant power drive mode is preferred.

[0100] The top of the continuous strip temperature resistance liquid level sensor 100 is provided with a top sealing area 20 to seal the continuous strip temperature resistance liquid level sensor 100.

[0101] Multiple detection groups 131 are connected to a multiplexing circuit 32 via leads. The multiplexing circuit 32 sequentially selects each detection group 131. A constant current source 31 provides a measuring current to the selected detection group 131. A signal conditioning circuit 33 amplifies, filters, and performs a reference comparison on the acquired voltage signal. An analog-to-digital converter 34 converts the analog signal into a digital signal. A microcontroller 35 processes the digital signal and outputs the liquid level information. A communication output circuit 37 can output 4–20mA, RS485, CAN, or other standard industrial signals.

[0102] The container 200 is equipped with an installation rail 61 and a snap-fit ​​connector 62. The continuous strip temperature resistance liquid level sensor 100 is fixed on the installation rail 61 by the snap-fit ​​connector 62.

[0103] like Figure 5 As shown, when the continuous strip temperature resistance liquid level sensor 100 in this embodiment is working, the heating resistance layer 15 heats the body 1 under the action of the heating drive circuit 36. Due to the different thermal conductivity and convective heat transfer capabilities of the liquid medium 202 and the gas phase space 203, the part of the body 1 immersed in the liquid medium 202 dissipates heat faster, and the temperature rise at its corresponding position is smaller, resulting in a smaller temperature difference; the part of the body 1 exposed in the gas phase space 203 dissipates heat slower, and the temperature rise at its corresponding position is larger, resulting in a larger temperature difference.

[0104] Therefore, a temperature variation distribution from the liquid phase region to the gas phase region is formed along the length direction of the body 1. After the temperature resistance detection layer 13 collects the temperature information at each height position, the microcontroller 35 constructs a temperature distribution curve along the length direction based on the temperature information, and obtains the height position corresponding to the liquid level surface 201 by identifying the positions of abrupt change points, maximum gradient points, inflection points or threshold transition zones in the temperature distribution curve.

[0105] When the temperature resistance detection layer 13 includes a heated detection array 132 and a reference detection array 133, the microcontroller 35 can determine the liquid level based on the temperature difference value at each corresponding position, that is: ΔT(z)=TH(z)-TR(z), where TH(z) is the detected temperature of the heated detection array 132 at height z, and TR(z) is the detected temperature of the reference detection array 133 at height z.

[0106] By using the temperature difference value at the corresponding location instead of a single absolute temperature value, the impact of changes in ambient temperature, changes in the overall temperature of the medium, and external disturbances on the accuracy of liquid level detection can be effectively reduced.

[0107] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A continuous strip-shaped temperature resistance liquid level sensor, characterized in that, include: The main body (1) is adapted to be arranged along the height direction of the container (200); A heating component (150) is disposed inside the body (1) and is used to heat the body (1); A temperature measuring component (130) is disposed inside the body (1). The temperature measuring component (130) includes a plurality of detection groups (131) arranged at intervals along the length direction of the body (1). Each detection group (131) includes a heating unit and a reference unit at the same height position. The thermal resistance between the heating unit and the heating component (150) is less than the thermal resistance between the reference unit and the heating component (150). The control module (30) is electrically connected to the heating component (150) and the temperature measuring component (130), respectively; The control module (30) is configured to calculate the temperature difference between the heated unit and the reference unit in the same detection group (131), and determine the liquid level height according to the distribution pattern of the temperature difference value corresponding to each detection group (131).

2. The continuous strip temperature resistance liquid level sensor according to claim 1, characterized in that, The heating unit is attached to the heating component (150), and an insulation layer is provided between the reference unit and the heating component (150); Alternatively, the distance between the reference unit and the heating component (150) is greater than the distance between the heated unit and the heating component (150).

3. The continuous strip temperature resistance liquid level sensor according to claim 1, characterized in that, The heating assembly (150) includes: Multiple serpentine resistor strips (151) are spaced apart along the length of the body (1).

4. The continuous strip temperature resistance liquid level sensor according to claim 1, characterized in that, The body (1) includes: A heating zone and two detection zones are provided in the width direction of the body (1). The heating zone is located between the two detection zones, the heating assembly (150) is located in the heating zone, and the heating unit and the reference unit are respectively located in the two detection zones. The protective zone is located on the side of the detection zone away from the heating zone.

5. The continuous strip temperature resistance liquid level sensor according to any one of claims 1-3, characterized in that, The body (1) comprises the following components arranged sequentially along its thickness direction: A reinforcing layer (17) is used to improve the rigidity of the body (1); The base layer (16) serves as the supporting carrier of the body (1); The heating resistance layer (15) is provided with the heating assembly (150); Insulating layer (14) is used to achieve electrical isolation; The temperature resistance detection layer (13) is provided with the temperature measuring component (130).

6. The continuous strip temperature resistance liquid level sensor according to claim 5, characterized in that, The body (1) includes: A back insulating layer (18) is disposed on the outside of the reinforcing layer (17); A surface insulating thermally conductive layer (12) is disposed on the outside of the temperature resistance detection layer (13).

7. The continuous strip temperature resistance liquid level sensor according to claim 6, characterized in that, The body (1) includes: An outer protective layer (11) is disposed outside the surface insulating and thermally conductive layer (12), and the outer protective layer (11) is made of one or more of FEP, PFA, PTFE or ETFE materials.

8. The continuous strip temperature resistance liquid level sensor according to claim 5, characterized in that, The reinforcing layer (17) is provided with: Multiple grooves are arranged at intervals along the length direction of the body (1), and each groove extends along the width direction of the body (1).

9. The continuous strip temperature resistance liquid level sensor according to any one of claims 1-3, characterized in that, The continuous strip-shaped temperature resistance liquid level sensor includes: A counterweight assembly (40) is provided at the bottom of the body (1), and the counterweight assembly (40) is used to keep the body (1) taut when it is suspended; And / or, a protective sleeve (50), the body (1) is detachably disposed within the protective sleeve (50).

10. A method for measuring liquid level using a continuous strip temperature resistance liquid level sensor according to any one of claims 1-9, characterized in that, include: S1. Drive the heating assembly (150) to heat the body (1) to form a temperature field in the length direction of the body (1); S2. Collect temperature detection signals from multiple detection groups (131) at different height positions; S3. Construct a temperature difference distribution curve along the length direction of the body (1) based on the temperature detection signal; S4. Determine the liquid level height based on the location of the abrupt change point or gradient change in the temperature difference distribution curve.

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