Water level detection device based on TDR principle
Through the water level detection device based on the TDR principle, the problem of increasing error in traditional water level meters in high temperature environments is solved, high-precision and low-deviation water level measurement is achieved, and the measurement range and applicable scenarios are expanded.
Patent Information
- Application Number
- CN202421640431.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-07-11
- Publication Date
- 2025-04-11
- Estimated Expiration
- 2034-07-11
AI Technical Summary
Traditional water level gauges are easily affected in high temperature environments, resulting in increased errors and are easily adsorbed by water pressure deformation and impurities, resulting in inaccurate measurements.
The water level detection device based on the TDR principle is adopted. The device includes an outer conductor cylinder, a probe, a cable adapter and a roller. The reflection time is measured by the TDR device to calculate the water level. The roller outside the outer conductor cylinder facilitates the equipment to move up and down in the water well, and the hollow support structure ensures that the inner conductor is parallel to the pipe wall.
It improves measurement accuracy and has a high resolution of 0.0018m, eliminates deviations caused by temperature offset and physical deformation, expands the measurement range and applicable scenarios, and the equipment structure design simplifies installation and operation.
Smart Images
Figure CN222748082U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of water level detection, in particular to a water level detection device based on the TDR principle. Background Art
[0002] The existing water level measurement methods include pressure method, bubble method, ultrasonic method and so on. Among the existing methods, the pressure method is the most widely used.
[0003] The pressure water level gauge measures the water level through a pressure sensor based on the principle of hydrostatic pressure that the pressure is proportional to the water depth. There are two types of pressure water level gauges: one is the piezoresistive water level gauge; the other is the bubble water level gauge. Although both use pressure sensors to collect signals and analyze data to derive the water level, the pressure sensor of the piezoresistive water level gauge needs to be installed underwater, while the pressure sensor of the bubble water level gauge is installed inside the instrument on the shore, and the overall process of water level measurement is achieved by blowing air into the water through a blowpipe.
[0004] The pressure water level gauge has high sensitivity, but it may be affected in high temperature environment, resulting in increased error. It is also easy to be deformed by water pressure and cause drift. Long-term immersion in water and adsorption by algae will cause errors in the pressure sensor. This will lead to inaccurate measurement. The pressure sensor is an active device. Long-term immersion in water requires high sealing of the sensor. Once leakage occurs due to aging of the seal, the equipment will be paralyzed and cannot be used.
[0005] In the related art, the technical problem that the traditional water level meter is affected by temperature and impurities, resulting in inaccurate liquid level measurement, has not yet been effectively solved. Utility Model Content
[0006] The utility model aims to provide a water level detection device based on the TDR principle, so as to solve the problem in the related art that the traditional water level meter is affected by temperature and impurities, resulting in inaccurate liquid level measurement.
[0007] In order to achieve the above purpose, the utility model adopts the following technical solutions:
[0008] A water level detection device based on the TDR principle comprises an outer conductor tube, which is a hollow cylinder without a bottom surface. A cable adapter is arranged on the top of the outer conductor tube, and the top of the cable adapter is connected to a TDR device via a coaxial cable. A probe is arranged on the axis inside the outer conductor tube, and the probe is connected to the coaxial cable inside the outer conductor tube via the cable adapter.
[0009] It is further configured as follows: a steel wire rope is connected to the top of the cable adapter.
[0010] It is further configured as follows: a hollow support is surrounded by the axis of the outer conductor tube, the hollow support is a spiral body, and the hollow support is inside the outer conductor tube.
[0011] It is further configured as follows: the hollow support abuts against the inner wall of the outer conductor tube, and the hollow support is fixedly connected to the top of the inner part of the outer conductor tube.
[0012] It is further configured as follows: a roller is arranged on the outer side of the outer conductor tube, and the roller rolls on the inner wall of the measured water well.
[0013] It is further configured that: at least four rollers are arranged outside the outer conductor tube.
[0014] It is further configured as follows: the roller is fixedly connected to the outer side wall of the outer conductor tube through a roller bracket.
[0015] Compared with the prior art, the beneficial technical effects of the utility model are as follows: the measurement accuracy of the utility model is higher, with a high resolution of 0.0018m. By rolling up and down, the measurement range can be increased. Theoretically, the measured water level range becomes 0-well depth, and the deviation caused by temperature offset and physical deformation in the traditional method is eliminated. Rollers are arranged on the outside of the outer conductor tube. These rollers not only facilitate the up and down movement and sliding of the equipment in environments such as water wells, but also effectively avoid the problem of getting stuck due to the rough pipe wall, thereby expanding the measurement range and applicable scenarios. At the same time, the spiral hollow support structure is cleverly introduced into the inner part of the outer conductor tube and is made of polytetrafluoroethylene material to ensure that the inner conductor and the pipe wall remain parallel, improve the signal transmission quality, and optimize the internal space utilization. In addition, the wire rope design connected to the top of the cable adapter provides a flexible, safe and reliable solution for the hoisting and height adjustment of the equipment. This design not only simplifies the installation and disassembly process, reduces labor intensity, but also improves work efficiency and allows the equipment to be easily operated in complex environments. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] In order to more clearly illustrate the specific implementation methods of the utility model or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.
[0017] Figure 1 It is a schematic diagram of the overall structure of the utility model;
[0018] Figure 2 It is the internal structure diagram of the utility model;
[0019] Figure 3 is a schematic diagram of the structure of the sensor element;
[0020] Figure 4 It is a segmented schematic diagram of the sensing element and the coaxial cable;
[0021] Figure 5 Schematic diagram of the reflection time of the signal transmitted by the device.
[0022] Figure numerals: 1. coaxial cable; 2. cable adapter; 3. outer conductor barrel; 4. probe; 5. hollow support; 6. roller; 7. roller bracket; 8. water well. DETAILED DESCRIPTION
[0023] The technical solution of the utility model will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.
[0024] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.
[0025] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.
[0026] Example
[0027] Reference Figure 1-2 , is a water level detection device based on the TDR principle disclosed by the utility model, which includes: an outer conductor tube, which is a hollow cylinder without a bottom surface, and a cable adapter 2 is arranged on the top of the outer conductor tube, and the top of the cable adapter 2 is connected to the TDR device through a coaxial cable; a probe 4 is arranged on the axis inside the outer conductor tube, and the probe 4 is connected to the coaxial cable through the cable adapter 2 inside the outer conductor tube.
[0028] The utility model is a passive device, and there is no need to consider sealing. It can use a stainless steel structure, is corrosion-resistant, has no pollution to water, is not affected by external environment such as temperature, and can maintain high-precision observation continuously. The utility model is installed in the water, and the sensing element is a coaxial cable 1 structure. This method uses the medium between the inner conductor and the outer conductor as air and water. The dielectric constant of air is 1, and the dielectric constant of water is about 80. The difference between the two is large, so even if there are attachments, it does not affect the reflection measurement. The resolution of the pressure water level gauge is 0.01 meters, and the resolution of the TDR principle, converted at an accuracy of 12ps, the resolution of the TDR principle water level measurement can reach 0.0018 meters, which is a significant improvement.
[0029] It is further configured that: a steel wire rope is connected to the top of the cable adapter 2. The steel wire rope is used to hoist the utility model, and the height of the equipment can be adjusted by adjusting the steel wire rope.
[0030] Specifically, as a high-strength, wear-resistant, and corrosion-resistant hoisting material, the steel wire rope can withstand large tension to ensure the stability and safety of the equipment during the hoisting process. At the same time, the connection point between the steel wire rope and the cable adapter 2 also needs to be carefully designed to ensure the firmness and reliability of the connection.
[0031] It is further configured as follows: a hollow support 5 is surrounded by the axis of the outer conductor tube, the hollow support 5 is a spiral body, and the hollow support 5 is inside the outer conductor tube. The hollow support 5 abuts against the inner wall of the outer conductor tube, and the hollow support 5 is fixedly connected to the top of the inner part of the outer conductor tube. The hollow support 5 is to ensure that the inner conductor in the middle remains parallel to the tube wall, and a spiral uniform support is adopted, and the material of the hollow support 5 is polytetrafluoroethylene.
[0032] Specifically, the spiral hollow support 5 structure can be evenly distributed inside the outer conductor tube, effectively supporting and fixing the inner conductor in the middle, ensuring that the inner conductor always remains parallel to the tube wall during movement or operation. This parallelism is crucial for the stability and accuracy of signal transmission, especially in situations where precise measurement is required. The close abutment and fixed connection between the hollow support 5 and the inner wall of the outer conductor tube enhances the stability and rigidity of the entire structure. This helps to reduce equipment shaking or deformation caused by external factors (such as vibration, impact, etc.), thereby improving the reliability and service life of the equipment. Choosing polytetrafluoroethylene as the material for the hollow support 5 has many advantages. Polytetrafluoroethylene has the characteristics of extremely low friction coefficient, good wear resistance, corrosion resistance and high temperature resistance. These characteristics enable the hollow support 5 to maintain stable performance during long-term use, reducing the risk of performance degradation or failure due to wear or corrosion.
[0033] It is further configured as follows: a roller 6 is provided on the outside of the outer conductor tube, and the roller 6 rolls on the inner wall of the measured water well 8. At least four rollers 6 are provided on the outside of the outer conductor tube. The roller 6 is fixedly connected to the outer wall of the outer conductor tube through a roller bracket 7. In order to increase the measuring range, the utility model is made into a slideway type, and the outer side of the outer conductor tube is provided with a roller 6, which is convenient for moving up and down and sliding. The roller 6 contacts the wall of the water well 8, which can avoid being stuck due to the rough wall of the tube.
[0034] Specifically, the slide-type design combined with the use of roller 6 enables the outer conductor tube to move more flexibly in the water well 8, thereby expanding the measurement range. Whether it is a deep well or a shallow well, the measurement can be accurately performed by adjusting the position of the outer conductor tube, thereby improving the comprehensiveness and accuracy of the measurement. As the contact point between the outer conductor tube and the wall of the water well 8, the roller 6 bears the main friction and wear. Compared with directly allowing the outer conductor tube to contact the wall, the design of the roller 6 effectively reduces the wear and damage of the outer conductor tube and extends the service life of the equipment. Because the roller 6 can ensure the stability and stability of the outer conductor tube during movement, the measurement error caused by shaking or instability of the equipment is reduced.
[0035] The principle steps of the utility model for detecting water level:
[0036] 1. Electromagnetic waves are transmitted in the coaxial cable 1. When encountering impedance mismatch, reflection will occur. The reflected electromagnetic waves will be received by the TDR equipment, and the position of the reflection point can be calculated.
[0037] 2. The sensing element is a coaxial cable 1 structure, the outer conductor tube is equivalent to the outer conductor, the probe 4 is equivalent to the inner conductor, and the space between the outer conductor and the inner conductor is air, such as Figure 3 As shown, the impedance of the sensor element can be calculated at this time: Z = (60 / √Er)*ln(D / d), where Z is the impedance, Er is the dielectric constant of the intermediate medium, D is the diameter of the outer conductor, and d is the diameter of the inner conductor.
[0038] 3. The dielectric constant of air is 1, and the dielectric constant of water is about 80 (varies with temperature), so the impedances are:
[0039] Assuming D = 100mm, d = 6mm, when the intermediate medium is air: Z1 = (60 / √Er)*ln(D / d) = 60*2.8134 = 168.8046;
[0040] When the intermediate medium is water: assuming room temperature, the dielectric constant of water is 80; Z2 = (60 / √Er)*ln(D / d) = (60 / 8.944)*2.8134 = 18.8734.
[0041] 4. The impedance of coaxial cable 1 is 50 ohms, and the other two are Z1 and Z2.
[0042] 5.Reference Figure 4 When the electromagnetic wave is transmitted forward along the cable, when it encounters the connection between Z0 and Z1, part of the electromagnetic wave will be reflected, which is called the first reflection, and another part will continue to transmit forward. When it reaches the connection between Z1 and Z2, a second reflection will occur.
[0043] 6.Reference Figure 5 , the length of the cable is known, assuming it is L0, and then the device is used to capture two reflections, recording the time as t1 and t2 respectively. According to the formula ka=((c*(t2-t1)) / 2L) 2 , c is 3x10 8 m / s; ka is the dielectric constant of the mixture of air and polytetrafluoroethylene. Before leaving the factory, ka can be calculated by measuring air, that is, knowing L and t2 and t1. The above formula can also be converted to:
[0044] 7. We have obtained L in the above text. If we know L0, we can get the water depth L1=L+L0.
[0045] 8. In order to increase the measuring range, the sensing element is made into a slideway type, and the outer conductor tube is provided with a roller 6 on the periphery, which is convenient for moving up and down. The roller 6 contacts the wall of the water well 8 to avoid getting stuck due to the rough wall. The hollow support 5 is to ensure that the middle probe 4 is parallel to the wall of the pipe, and a spiral uniform support is adopted. The material of the hollow support 5 is polytetrafluoroethylene.
[0046] The working principle and beneficial effects of the utility model are as follows: the measurement accuracy of the utility model is higher, with a high resolution of 0.0018m. By rolling up and down, the measurement range can be increased. Theoretically, the measured water level range becomes 0-well depth, and the deviation caused by temperature offset and physical deformation in the traditional method is eliminated. Rollers 6 are arranged on the outside of the outer conductor tube. These rollers 6 not only facilitate the up and down movement and sliding of the equipment in the environment such as the water well 8, but also effectively avoid the problem of getting stuck due to the rough pipe wall, thereby expanding the measurement range and applicable scenarios. At the same time, the spiral hollow support 5 structure is cleverly introduced into the inner part of the outer conductor tube and is made of polytetrafluoroethylene material to ensure that the inner conductor and the pipe wall remain parallel, improve the signal transmission quality, and optimize the internal space utilization. In addition, the wire rope design connected to the top of the cable adapter 2 provides a flexible, safe and reliable solution for the hoisting and height adjustment of the equipment. This design not only simplifies the installation and disassembly process, reduces labor intensity, but also improves work efficiency and allows the equipment to be easily operated in complex environments.
[0047] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the utility model, rather than to limit it. Although the utility model has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the utility model.
Claims
1. A water level detection device based on TDR principle, characterized in that: include: An outer conductor cylinder, the outer conductor cylinder being a hollow cylinder without a bottom surface, a cable adapter (2) being arranged on the top of the outer conductor cylinder, and a TDR device being connected to the top of the cable adapter (2) via a coaxial cable; A probe (4) is arranged at the axis center inside the outer conductor cylinder, and the probe (4) is connected to the coaxial cable through the cable adapter (2) inside the outer conductor cylinder.
2. A water level detection device based on the TDR principle according to claim 1, characterized in that: include: The top of the cable adapter (2) is connected with a steel wire rope.
3. A water level detection device based on TDR principle according to claim 1, characterized in that: include: A hollow support (5) surrounds the axis of the outer conductor tube, and the hollow support (5) is a spiral body. The hollow support (5) is inside the outer conductor tube.
4. A water level detection device based on TDR principle according to claim 3, characterized in that: include: The hollow support (5) abuts against the inner wall of the outer conductor tube, and the hollow support (5) is fixedly connected to the top of the inner part of the outer conductor tube.
5. The water level detection device based on the TDR principle according to claim 1 is characterized in that: include: A roller (6) is arranged on the outside of the outer conductor tube, and the roller (6) rolls on the inner wall of the water well (8) to be tested.
6. The water level detection device based on the TDR principle according to claim 5 is characterized in that: include: At least four rollers (6) are arranged outside the outer conductor tube.
7. The water level detection device based on the TDR principle according to claim 5 is characterized in that: include: The roller (6) is fixedly connected to the outer side wall of the outer conductor tube via a roller bracket (7).