Capacitive liquid level measuring device capable of changing range and measuring method thereof

Abstract

The invention provides a variable-range capacitive liquid level measuring device and a measuring method thereof, and relates to the technical field of liquid level measurement, the variable-range capacitive liquid level measuring device comprises an electronic master controller and a linear detection probe, the linear detection probe comprises inner electrodes and outer electrodes, the inner electrodes comprise a first inner electrode and a second inner electrode, and the outer electrodes comprise a first outer electrode and a second outer electrode. The second inner electrode is sleeved on the inner side of the first inner electrode, and the second outer electrode is sleeved on the inner side of the first outer electrode. By means of a coaxial sleeve type mechanism formed by the inner electrode and the outer electrode, controllable adjustment of the measuring range of the probe is achieved, and real-time monitoring of the liquid level of a container with the effective storage height of 0-2 m can be met; by means of the base at the bottom of the linear measurement probe, the installation perpendicularity is guaranteed, and the accuracy of measurement data is improved; through reasonable model selection of materials and structural design, online measurement of the liquid level of a measured medium under the extremely low temperature environment condition or measurement of the liquid level of an ultra-low temperature liquid medium is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of liquid level measurement, and in particular relates to a capacitive liquid level measuring device with an energy variable range and a measuring method thereof. Background Art

[0002] The capacitive level meter is based on the principle of capacitive sensing. It uses a capacitive sensor to convert the liquid level in the container into capacitance. When the liquid level inside the container changes, it will cause a change in capacitance. The liquid level value is inferred by measuring the capacitance between the two electrodes.

[0003] Based on the current research and development status of capacitive level gauges, the problem of the measured data being affected by the different designs of the measuring devices themselves has received increasing attention. For example, due to the wide variety of storage containers, the depths at which the level gauges need to be installed are also different. During use, if the probe of the level gauge is too long, it will interfere with the bottom of the container, and the container mouth cannot be fixed, resulting in installation failure; if the probe is too short, after a certain period of time, the liquid level will drop to the bottom of the container, and the probe may not be able to reach the liquid surface, resulting in a large blind spot at the bottom of the measurement, and it is impossible to obtain real-time liquid level data. In addition, for storage containers of different heights, it is impossible to stock liquid level gauges in large quantities, which has an adverse impact on production costs and service periods. In addition, in some special occasions, there are relatively few devices that can accurately measure the liquid level of extremely low-temperature materials, such as liquid oxygen, liquid nitrogen, and liquid natural gas.

[0004] Therefore, it is necessary to propose a capacitive liquid level measuring device with variable energy range and a measuring method thereof, which can simultaneously realize real-time monitoring of the liquid level and effective adjustment of the measuring range in an extremely low temperature environment. Summary of the invention

[0005] In view of the problems existing in the prior art, the present invention provides a capacitive liquid level measuring device with an energy variable range and a measuring method thereof. The present invention realizes controllable adjustment of the probe measurement range through a coaxial sleeve mechanism composed of an inner electrode and an outer electrode, which can meet the requirements of real-time liquid level monitoring of a container with an effective storage height of 2m. The base at the bottom of the linear measurement probe is used to ensure the verticality of the installation and increase the accuracy of the measurement data. Through the reasonable selection of materials and the design of the structure, the online measurement of the liquid level of the measured medium under extremely low temperature conditions, or the liquid level measurement of ultra-low temperature liquid media, is realized.

[0006] In one aspect, the present invention provides a capacitive liquid level measuring device with a variable energy range, which includes a linear detection probe, a flange base, a mounting base, a base, and an electronic main controller.

[0007] A connecting piece is fixed to the upper part of the flange base, the electronic main controller is arranged at the first end of the connecting piece and a first sealing ring is arranged between the two, the mounting seat includes a threaded portion and a boss portion, the threaded portion is threadedly connected to the second end of the connecting piece and a second sealing ring is arranged between the two, the boss portion includes a first boss and a second boss, and the diameter of the first boss is greater than the diameter of the second boss; the first end of the linear detection probe is connected to the boss portion, and the second end of the linear detection probe is connected to the base, and the base includes a counterweight end cover, a first connecting boss and a second connecting boss, the first connecting boss and the second connecting boss are arranged on the counterweight end cover, and the diameters of the counterweight end cover, the first connecting boss and the second connecting boss decrease in sequence;

[0008] The linear detection probe comprises an inner electrode and an outer electrode sleeved outside the inner electrode, and a cavity capable of accommodating the measured medium is provided between the outer wall of the inner electrode and the inner wall of the outer electrode;

[0009] The inner electrode comprises a first inner electrode and a second inner electrode that can be telescopically sleeved, the first end of the first inner electrode is connected to the second boss, the second end of the first inner electrode is sleevedly connected to the first end of the second inner electrode and the length of the second inner electrode extending into the first inner electrode can be adjusted, and the second end of the second inner electrode is connected to the second connecting boss;

[0010] The outer electrode comprises a first outer electrode and a second outer electrode that can be telescopically sleeved, the first end of the first outer electrode is connected to the first boss, the second end of the first outer electrode is sleeved and connected to the first end of the second outer electrode and the length of the second outer electrode extending into the first outer electrode can be adjusted, and the second end of the second inner electrode is connected to the first connecting boss;

[0011] The electronic main controller includes a main shell, a digital tube, a window baffle, a numerical control unit, an upper cover and a cable connector. The digital tube is connected to the main shell through a fixing part, the window baffle is slidably connected to the main shell, the numerical control unit is arranged inside the main shell, the upper cover is connected to the main shell, a cable connector is provided on one side of the main shell, and the first end of the connector is connected to the connector connector on the main shell.

[0012] Preferably, the inner electrode and the outer electrode are both cylindrical hollow tube structures, and the inner electrode and the outer electrode as a whole present a coaxial sleeve-type telescopic mechanism.

[0013] Preferably, positioning screw holes are provided on both sides of the shafts of the first outer electrode and the second outer electrode in mirror symmetry and are connected by bolt groups, and the material of the inner electrode, the outer electrode and the bolt group is low-temperature resistant 304 stainless steel.

[0014] Preferably, one side of the shaft body of the first outer electrode and the second outer electrode is provided with a through hole of equal diameter.

[0015] Preferably, the maximum liquid level measurement height of the linear detection probe is 2m.

[0016] Preferably, the first end of the first inner electrode and the second boss, the second end of the second inner electrode and the second connecting boss, the first end of the first outer electrode and the first boss, and the second end of the second inner electrode and the first connecting boss are all fixedly connected by bolts.

[0017] Preferably, the wall thickness of the inner electrode and the outer electrode is 3-5 mm.

[0018] Preferably, a display screen window is opened at one side of the main shell, the digital tube and the window baffle are both arranged at the display screen window, a connector joint is arranged at the lower position of the main shell, and the connector joint is threadedly connected to the upper part of the connector.

[0019] Preferably, the diameter of the accommodating cavity between the inner electrode and the outer electrode is 2-3 mm, and the mounting seat is made of insulating polytetrafluoroethylene.

[0020] Another aspect of the present invention provides a measurement method of the capacitive liquid level measurement device based on the above energy variable range, which comprises the following steps:

[0021] S1. Install the linear detection probe: fix the first ends of the first inner electrode and the first outer electrode on the mounting seat respectively, and fix the second ends of the second inner electrode and the second outer electrode on the base respectively, so that the second inner electrode moves in the same direction and speed as the second outer electrode moves linearly;

[0022] S2. Adjust the measuring range of the linear detection probe based on the target detection range: determine the target detection range based on the target detection liquid level and adjust the length of the second outer electrode extending into the first outer electrode. After the adjustment is completed, fasten the first outer electrode and the second outer electrode with a bolt group and perform radial positioning;

[0023] S3, inserting the linear detection probe into the storage tank container and placing the flange base on the top of the storage tank container;

[0024] S4. Perform liquid level measurement and output the actual liquid level measurement value: The measured medium rises and falls in the cavity containing the inner electrode and the outer electrode, and the actual liquid level measurement value is calculated and output by measuring the change in capacitance between the inner electrode and the outer electrode.

[0025] Compared with the prior art, the present invention has the following advantages:

[0026] (1) In the energy variable range capacitive liquid level measuring device of the present invention, both the inner electrode and the outer electrode are cylindrical hollow tubular structures, and the probe is assembled as a coaxial sleeve mechanism, which realizes the controllable adjustment of the probe measurement range and can meet the requirements of real-time liquid level monitoring of containers with an effective storage height of 2m.

[0027] (2) The energy variable range capacitive liquid level measuring device of the present invention ensures the verticality of the overall measuring device when installed in the container by means of a base at the bottom of the linear measuring probe, thereby increasing the accuracy of the device's measurement data.

[0028] (3) The variable-range capacitive liquid level measuring device of the present invention is designed with an independent electronic main controller, which can achieve 4-20mA analog signal output. By rationally selecting the materials and designing the structures of the internal and external electrodes, it can achieve online measurement of the liquid level of the measured medium under extremely low temperature conditions, or the liquid level measurement of ultra-low temperature liquids such as liquid oxygen, liquid nitrogen, liquid natural gas and other media. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of the overall structure of the energy variable range capacitive liquid level measuring device of the present invention;

[0030] Figure 2 It is a schematic diagram of the explosion structure of the present invention;

[0031] Figure 3 It is a structural schematic diagram of the electronic main controller in the present invention;

[0032] Figure 4 It is a schematic cross-sectional view of part of the structure of the linear detection probe in the present invention;

[0033] Figure 5 It is a block diagram of the measurement principle of the present invention;

[0034] Figure 6 It is a flow chart of the measuring method of the present invention.

[0035] Main reference numerals:

[0036] Electronic main controller 1, main housing 101, connector 1011, digital tube 102, fixing part 103, window baffle 104, numerical control unit 105, upper cover 106, cable connector 107, connector 108, first sealing ring 109, flange base 110, mounting base 111, second sealing ring 112, base 113, linear detection probe 2, inner electrode 21, first inner electrode 211, second inner electrode 212, outer electrode 22, first outer electrode 221, second outer electrode 222;

[0037] Microprocessor 1051, capacitance detection circuit 1052, display module 1053, power supply module 1054;

[0038] Threaded portion 1111 , first boss 1112 , second boss 1113 , counterweight end cover 1131 , first connecting boss 1132 , second connecting boss 1133 . DETAILED DESCRIPTION

[0039] In order to fully describe the technical content, objectives and effects of the present invention, the following will be described in detail with reference to the accompanying drawings.

[0040] On the one hand, if Figure 1 to Figure 4 As shown, the present invention provides a capacitive liquid level measuring device with a variable energy range, which includes a linear detection probe 2, a flange base 110, a mounting base 111, a base 113 and an electronic main controller 1.

[0041] The electronic main controller 1 includes a main housing 101 , a digital tube 102 , a fixing member 103 , a window baffle 104 , a numerical control unit 105 , an upper cover 106 and a cable connector 107 .

[0042] The digital tube 102 is connected to the main shell 101 through the fixing part 103 to present the real-time data of the liquid level. The window baffle 104 is slidably connected to the main shell 101. The numerical control unit 105 is arranged inside the main shell 101. The upper cover 106 is connected to the main shell 101. The cable connector 107 is arranged on one side of the main shell 101 to realize the interaction with the external power supply and communication signal. The first end of the connector 108 is connected to the connector connector 1011 on the main shell 101, and a first sealing ring 109 is arranged between the main shell 101 and the connector 108.

[0043] The base 113 includes a counterweight end cover 1131, a first connection boss 1132 and a second connection boss 1133, which are successively reduced in diameter. The first connection boss 1132 and the second connection boss 1133 are successively arranged on the counterweight end cover 1131. The mounting seat 111 includes a threaded portion 1111, a first boss 1112 and a second boss 1113. The threaded portion 1111 is connected to the second end of the connector 108 and a second sealing ring 112 is arranged therebetween. The connector 108 is covered with a flange base 110, and the arrangement of the flange base 110 facilitates fixing the device on the top of the container.

[0044] The linear detection probe 2 includes an inner electrode 21 and an outer electrode 22. Both the inner electrode 21 and the outer electrode 22 are cylindrical hollow tube structures. The inner electrode 21 and the outer electrode 22 are integrally formed into a coaxial sleeve-type telescopic mechanism. In a specific application, both the inner electrode and the outer electrode are cylindrical hollow tube shapes and assembled into a coaxial sleeve-type structure, thereby achieving coaxial positioning and installation between the two.

[0045] The linear detection probe comprises an inner electrode 21 and an outer electrode 22 sleeved outside the inner electrode 21 , and a cavity capable of accommodating the measured medium is provided between the outer wall of the inner electrode 21 and the inner wall of the outer electrode 22 .

[0046] The inner electrode 21 includes a first inner electrode 211 and a second inner electrode 212 that can be telescopically sleeved, the first end of the first inner electrode 211 is connected to the second boss, the second end of the first inner electrode 211 is sleeved and connected to the first end of the second inner electrode 212 and the length of the second inner electrode 212 extending into the first inner electrode 211 can be adjusted, and the second end of the second inner electrode 212 is connected to the second connection boss. The outer electrode 22 includes a first outer electrode 221 and a second outer electrode 222 that can be telescopically sleeved, the first end of the first outer electrode 221 is connected to the first boss 1112, the second end of the first outer electrode 221 is sleeved and connected to the first end of the second outer electrode 222 and the length of the second outer electrode 222 extending into the first outer electrode 221 can be adjusted, and the second end of the second inner electrode 222 is connected to the first connection boss.

[0047] On the one hand, the base 113 can prevent the linear detection probe 2 from directly contacting the bottom of the container, and on the other hand, it can keep the device in a vertical state, and the verticality of the device will not be affected by liquid shaking, thereby increasing the accuracy of the measurement data of the device.

[0048] Positioning screw holes are provided on both sides of the shaft body of the first outer electrode 221 and the second outer electrode in mirror symmetry, and are connected by bolt groups, and the material of the connecting bolt groups is low-temperature resistant 304 stainless steel. The liquid level measurement height range of the linear detection probe 2 can reach 2m. An equal-diameter through hole is provided on one side of the shaft body of the first outer electrode 221 and the second outer electrode 222 to ensure smooth gas and liquid flow inside the container during measurement and prevent pressure fluctuations. The material of the inner electrode 1 and the outer electrode 2 are both low-temperature resistant 304 stainless steel, and the wall thickness of the inner electrode 1 and the outer electrode 2 is controlled within the range of 3 to 5 mm. It can measure the liquid level of the measured medium online under extremely low temperature environment conditions, or measure the liquid level of ultra-low temperature liquids such as liquid oxygen, liquid nitrogen, liquid natural gas (LNG) and other media.

[0049] A display screen window is provided on one side of the main housing 101, and the digital tube 102 and the window baffle 104 are both provided at the display screen window. A connector 1011 is provided at the lower position of the main housing 101. The spacing between the inner electrode 1 and the outer electrode 2 is 2 to 3 mm, and the material of the mounting seat 111 is polytetrafluoroethylene, which achieves the purpose of insulation and avoids short circuit between electrodes without affecting the change of capacitance value. The signal lines of the inner electrode 21 and the outer electrode 22 are directly led out from the inside of the linear detection probe 2, which reduces the cable capacitance, thereby reducing the influence of the change of the cable length position.

[0050] The second aspect of the present invention, as Figure 6 As shown, a measuring method of a capacitive liquid level measuring device with a variable energy range is provided, comprising the following steps:

[0051] S1. Install the linear detection probe: fix the first ends of the first inner electrode and the first outer electrode on the mounting base respectively, and fix the second ends of the second inner electrode and the second outer electrode on the base respectively, so that the second inner electrode moves in the same direction and speed as the second outer electrode moves linearly, and when the length of the second outer electrode extending into the first outer electrode is adjusted, the length of the second inner electrode extending into the first inner electrode can be adjusted synchronously.

[0052] S2. Adjust the range of the linear detection probe based on the target detection range: determine the target detection range based on the target detection liquid level and adjust the length of the second outer electrode extending into the first outer electrode so that the range of the linear detection probe meets the requirements. After the adjustment is completed, fasten the first outer electrode and the second outer electrode with a bolt group and perform radial positioning.

[0053] S3. Insert the linear detection probe into the storage tank container and place the flange base on the top of the storage tank container, and fix the entire device with the help of the flange base.

[0054] S4. Perform liquid level measurement and output the actual liquid level measurement value: The measured medium rises and falls in the cavity containing the inner electrode and the outer electrode, and the actual liquid level measurement value is calculated and output by measuring the change in capacitance between the inner electrode and the outer electrode.

[0055] In this embodiment, if Figure 5 As shown, the linear detection probe 2 senses the change of the liquid level, converts the liquid level rise and fall into the capacitance change through the capacitance detection chip in the numerical control unit 105, and realizes the conversion of digital quantity. With the microprocessor 1051 as the core, the corresponding peripheral circuit is added according to the actual needs to realize the configuration and control of the capacitance detection circuit 1052, the transmission and processing of data, etc. After the microprocessor 1051 receives the data of the capacitance detection circuit, it is finally restored to the liquid level after data processing calculation and conversion, and the liquid level is transmitted to the display screen of the communication and display module 1053 for intuitive display, and remote communication can be carried out through the 4-20mA circuit loop. The power module 1054 is used to provide power to the microprocessor 1051, the capacitance detection circuit 1052 and the communication and display module 1053.

[0056] By setting a counterweight base at the bottom of the linear detection probe, when the measuring device is inserted into the storage tank container, on the one hand, it prevents the linear detection probe from directly contacting the bottom of the container, and on the other hand, due to the effect of the counterweight base, the device can always be in a vertical state, and the verticality of the device will not be affected by the shaking of the liquid, thereby increasing the accuracy of the device's measurement data. A 2-3mm spacing is set between the inner and outer electrodes to form an accommodating space. At the same time, the upper ends of the first inner electrode and the first outer electrode are sleeved on the lower end of the mounting seat. The mounting seat is made of polytetrafluoroethylene. Without affecting the change in capacitance value, it achieves the purpose of insulation, thereby avoiding short circuits between electrodes. Positioning screw holes are symmetrically opened on both sides of the shaft body of the first outer electrode and the second outer electrode, and threaded fixed connection is achieved through a bolt group. And the material of the bolt group is low-temperature resistant 304 stainless steel, which can adapt to the extremely low temperature environment of the measured liquid. Reasonable material selection and optimized structure design are carried out for the inner and outer electrodes, both of which are low-temperature resistant 304 stainless steel. The wall thickness of the inner and outer electrodes is controlled within the range of 3-5mm, which can realize the online measurement of the liquid level of the measured medium under extremely low temperature environment conditions, or the liquid level measurement of ultra-low temperature liquids such as liquid oxygen, liquid nitrogen, liquid natural gas (LNG) and other media.

[0057] In practical applications, for container types with different effective storage heights, the range adjustment method is as follows: when the second outer electrode of the linear detection probe is stretched or contracted, since the first inner electrode and the first outer electrode are fixed on the upper fixed seat, both are immobile, and since the lower ends of the second inner electrode and the second outer electrode are fixed on the counterweight base, the second inner electrode will move in the same direction and speed as the second outer electrode moves linearly. When the required detection range is adjusted, the first outer electrode and the second outer electrode are fastened by a stainless steel bolt group, which plays a radial positioning role at the same time, ensuring that the linear detection probe does not move during normal operation, ensuring that the gap between the inner and outer electrodes is free of deviation, and thus reducing the capacitance value change error. Through holes are respectively opened on one side of the top shaft body of the first outer electrode and one side of the bottom shaft body of the second outer electrode, so that the gas and liquid inside the container can flow smoothly and prevent pressure fluctuations. When in use, the first inner electrode and the first outer electrode constitute the upper part of the capacitance of the linear detection probe, and the second inner electrode and the second outer electrode constitute the lower part of the capacitance of the linear detection probe. Since the change in the upper part of the capacitance is the same as the change in the lower part of the capacitance when the linear detection probe structure is stretched or contracted, the change in the overall measurement range does not affect the linearity of the overall linear detection probe measurement data. The measured medium rises and falls in the distance between the inner and outer electrodes, and the actual liquid level measurement value can be output by measuring the change in capacitance between the inner and outer electrodes and calculating and converting it.

[0058] The embodiments described above are only descriptions of the preferred implementation modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A capacitive liquid level measuring device with a variable energy range, characterized in that: It includes a linear detection probe, a flange base, a mounting base, a base and an electronic main controller. A connecting piece is fixed to the upper part of the flange base, the electronic main controller is arranged at the first end of the connecting piece and a first sealing ring is arranged between the two, the mounting seat includes a threaded portion and a boss portion, the threaded portion is threadedly connected to the second end of the connecting piece and a second sealing ring is arranged between the two, the boss portion includes a first boss and a second boss, and the diameter of the first boss is greater than the diameter of the second boss; the first end of the linear detection probe is connected to the boss portion, and the second end of the linear detection probe is connected to the base, and the base includes a counterweight end cover, a first connecting boss and a second connecting boss, the first connecting boss and the second connecting boss are arranged on the counterweight end cover, and the diameters of the counterweight end cover, the first connecting boss and the second connecting boss decrease in sequence; The linear detection probe comprises an inner electrode and an outer electrode sleeved outside the inner electrode, and a cavity capable of accommodating the measured medium is provided between the outer wall of the inner electrode and the inner wall of the outer electrode; The inner electrode comprises a first inner electrode and a second inner electrode that can be telescopically sleeved, the first end of the first inner electrode is connected to the second boss, the second end of the first inner electrode is sleevedly connected to the first end of the second inner electrode and the length of the second inner electrode extending into the first inner electrode can be adjusted, and the second end of the second inner electrode is connected to the second connecting boss; The outer electrode comprises a first outer electrode and a second outer electrode that can be telescopically sleeved, the first end of the first outer electrode is connected to the first boss, the second end of the first outer electrode is sleeved and connected to the first end of the second outer electrode and the length of the second outer electrode extending into the first outer electrode can be adjusted, and the second end of the second inner electrode is connected to the first connecting boss; The electronic main controller includes a main shell, a digital tube, a window baffle, a numerical control unit, an upper cover and a cable connector. The digital tube is connected to the main shell through a fixing part, the window baffle is slidably connected to the main shell, the numerical control unit is arranged inside the main shell, the upper cover is connected to the main shell, a cable connector is provided on one side of the main shell, and the first end of the connector is connected to the connector connector on the main shell.

2. The energy variable range capacitive liquid level measuring device according to claim 1, characterized in that: The inner electrode and the outer electrode are both cylindrical hollow tube structures, and the inner electrode and the outer electrode as a whole present a coaxial sleeve-type telescopic mechanism.

3. The energy variable range capacitive liquid level measuring device according to claim 1, characterized in that: Positioning screw holes are provided on both sides of the shaft of the first outer electrode and the second outer electrode in a mirror-symmetrical manner and are connected by a bolt group. The material of the inner electrode, the outer electrode and the bolt group is low-temperature resistant 304 stainless steel.

4. The energy variable range capacitive liquid level measuring device according to claim 1, characterized in that: A through hole with the same diameter is formed on one side of the shaft body of the first outer electrode and the second outer electrode.

5. The energy variable range capacitive liquid level measuring device according to claim 1, characterized in that: The maximum liquid level measurement height of the linear detection probe is 2m.

6. The energy variable range capacitive liquid level measuring device according to claim 1, characterized in that: The first end of the first inner electrode and the second boss, the second end of the second inner electrode and the second connecting boss, the first end of the first outer electrode and the first boss, and the second end of the second inner electrode and the first connecting boss are all fixedly connected by bolts.

7. The energy variable range capacitive liquid level measuring device according to claim 1, characterized in that: The wall thickness of the inner electrode and the outer electrode is 3-5 mm.

8. The energy variable range capacitive liquid level measuring device according to claim 1, characterized in that: A display screen window is provided at one side of the main shell, the digital tube and the window baffle are both arranged at the display screen window, a connector joint is provided at the lower position of the main shell, and the connector joint is threadedly connected to the upper portion of the connector.

9. The energy variable range capacitive liquid level measuring device according to claim 1, characterized in that: The diameter of the accommodating cavity between the inner electrode and the outer electrode is 2-3 mm, and the material of the mounting seat is insulating polytetrafluoroethylene.

10. A measuring method of a capacitive liquid level measuring device with a variable energy range according to any one of claims 1 to 8, characterized in that: It includes the following steps: S1. Install the linear detection probe: fix the first ends of the first inner electrode and the first outer electrode on the mounting seat respectively, and fix the second ends of the second inner electrode and the second outer electrode on the base respectively, so that the second inner electrode moves in the same direction and speed as the second outer electrode moves linearly; S2. Adjust the measuring range of the linear detection probe based on the target detection range: determine the target detection range based on the target detection liquid level and adjust the length of the second outer electrode extending into the first outer electrode. After the adjustment is completed, fasten the first outer electrode and the second outer electrode with a bolt group and perform radial positioning; S3, inserting the linear detection probe into the storage tank container and placing the flange base on the top of the storage tank container; S4. Perform liquid level measurement and output the actual liquid level measurement value: The measured medium rises and falls in the cavity containing the inner electrode and the outer electrode, and the actual liquid level measurement value is calculated and output by measuring the change in capacitance between the inner electrode and the outer electrode.

Images