Fool type capacitance liquid level meter and liquid level calibration method

Abstract

The invention provides a fool type capacitance liquid level meter and a liquid level calibration method.The fool type capacitance liquid level meter comprises a probe body, a circuit board is arranged in the probe body, a first support is arranged at the lower end of the probe body, a probe outer pipe is arranged at the lower end of the first support, a probe is arranged in the probe outer pipe, and a second support is arranged at the lower end of the probe outer pipe; and copper foils are respectively arranged in the probe outer tubes. According to the fool-type capacitance liquid level meter and the liquid level calibration method, the capacitance liquid level meter adopts fool-type design, is simple in structure, free of any movable or elastic component, extremely high in reliability, extremely small in maintenance amount and more convenient and rapid to use, the zero point and the measuring range of the capacitance liquid level meter are automatically calibrated, a measurement medium is automatically identified and calibrated, and the liquid level calibration accuracy is improved. The detection range of the capacitance liquid level meter is enlarged, and the capacitance liquid level meter can be conveniently adjusted.

Description

Technical Field

[0001] The invention relates to the technical field of capacitance liquid level gauges, in particular to a fool-proof capacitance liquid level gauge and a liquid level calibration method. Background Art

[0002] Capacitance level meter is a measuring instrument that uses the change of capacitance to measure the level of the medium in the container. Its working principle is based on a fixed electrode. When a fixed frequency measuring voltage is applied to the electrode, the current flowing through the capacitor depends on the height of the medium between the capacitor electrodes and is proportional to it. This means that by measuring the change of capacitance, the height or volume of the liquid can be calculated.

[0003] In the prior art, capacitive level meters need to be calibrated when they are used. The calibration of capacitive level meters includes static calibration method and dynamic calibration method. The static calibration method is to install the level meter on a standard container, add a standard liquid level and record the readings, and then draw a relationship curve between the standard liquid level and the capacitance value based on the recorded data. The dynamic calibration method requires the use of special equipment to simulate the change of the liquid level, and obtains the coefficient relationship between the measured value of the level meter and the actual liquid level by adjusting the capacitance value of the simulated capacitor and recording the corresponding readings. However, both static calibration and dynamic calibration require more steps to operate, and require professional personnel to operate, which is inconvenient to use. In order to solve this technical problem, a fool-proof capacitive level meter and a level calibration method are proposed. Summary of the invention

[0004] In view of the above-mentioned defects or deficiencies in the prior art, the present application aims to provide a fool-type capacitance level gauge, comprising a probe body, a circuit board is provided inside the probe body, a bracket one is provided at the lower end of the probe body, a probe outer tube is provided at the lower end of the bracket one, a probe is provided inside the probe outer tube, a bracket two is provided at the lower end of the probe outer tube, copper foils are provided inside the probe outer tubes, five copper foils with equal intervals and equal vertical lengths are respectively located between the inner arc surface of the probe outer tube and the outer arc surface of the probe, an upper cover is provided at the upper end of the probe body, an O-ring is sleeved in the groove in the middle part of the outer arc surface of the probe body, a waterproof joint is provided at the threading hole of the probe body, and a stainless steel tube is movably sleeved on the outer arc surface of the probe outer tube.

[0005] Preferably, the upper end of the probe body is an open structure.

[0006] Preferably, the upper end of the stainless steel tube is fixedly connected to the probe body, the lower end of the stainless steel tube is fixedly connected to the second bracket, and a liquid inlet hole is provided on the surface of the stainless steel tube.

[0007] Preferably, the stainless steel tube is connected to the bracket 2 and the probe body by full-circle welding, and the welding parts are polished for a smooth transition.

[0008] Preferably, the lower end of the probe outer tube is connected to the second bracket by hot melt adhesive.

[0009] Preferably, the upper end of the interior of the probe body is potted.

[0010] A method for calibrating a liquid level of a fool-type capacitance liquid level meter, using a fool-type capacitance liquid level meter, comprises the following steps:

[0011] Step 1: Program learning: First read the zero point value of each copper foil position and store it permanently. Then put the sensor into the liquid gently and evenly. When the sensor is completely immersed in the liquid, read the capacitance value of each segment and give a prompt. At the same time, use Y=20 / (CH-CL) to calculate the transformation ratio of each segment. Then lift the sensor up. After the oil control is completed, slowly put it into the liquid again at an even speed. The capacitance value is prompted again. When the transformation ratios of the two times are close to and less than the X value, the learning is confirmed to be successful.

[0012] Step 2, normal liquid level measurement: the current measurement medium is the learning medium. When the medium level is in the first section and does not submerge the second section, the liquid level conversion formula of the first section is H1=Y1*(C1X-C1L), where C1X is the currently measured capacitance value, C1L is the zero capacitance value of the first section, and Y1 is the transformation ratio of the first section; when the liquid level is in the second section, the liquid level is converted by the formula H2=(Y2*(C2X-C2L))+20, and the values ​​of the third and fourth sections are obtained in the same way. The value of the fifth section is calculated by averaging the transformation ratios of the first four sections. Finally, the converted values ​​are summarized and calculated by the processing chip in the circuit board to obtain the current liquid level height;

[0013] Step 3, critical point judgment: set a node size value to 20, when the next segment value is converted to 20, and the previous segment value is greater than the zero point value of the previous segment value, it is considered that the current liquid level is in the previous segment; when the next segment value is not in the current segment range position, but lower than this position, and the previous segment value has exceeded the saved zero point capacitance value, it is considered that the current liquid level is in the next segment; when the liquid level exceeds the previous segment, and the next segment value is not at the full position, the liquid level exceeds the preset threshold of the previous segment, it is considered that the current liquid level is in the previous segment;

[0014] Step 4: Liquid level calibration: When the capacitance values ​​of the first to fourth liquid levels are all greater than the zero capacitance value, and the measured values ​​of the first to third levels are less than the range capacitance value or greater than the range capacitance value, it is considered that a significant change has occurred in the medium and an updated calibration is required, which is then saved.

[0015] Beneficial effects: The fool-type capacitance liquid level meter and liquid level calibration method adopt a fool-type design, a simple structure, no movable or elastic components, extremely high reliability, minimal maintenance, and the use of the capacitance liquid level meter is more convenient and quick;

[0016] It can automatically calibrate the zero point and range of the capacitance level meter, automatically identify the measuring medium and make calibration, increase the detection range of the capacitance level meter, facilitate the adjustment of the capacitance level meter, and is easy to use. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Other features, objects and advantages of the present application will become more apparent by reading the detailed description of non-limiting embodiments made with reference to the following drawings:

[0018] Figure 1 It is a schematic diagram of the structure of the present invention;

[0019] Figure 2 It is a structural schematic diagram of the overall device of the present invention from the front;

[0020] Figure 3 It is a schematic structural diagram of a front cross-section of the overall device of the present invention;

[0021] Figure 4 It is a schematic diagram of the front cross-sectional structure of the overall device of the present invention.

[0022] In the figure: 1 upper cover, 2 probe body, 3 circuit board, 4 O-ring, 5 bracket 1, 6 stainless steel tube, 7 probe outer tube, 8 probe, 9 copper foil, 10 bracket 2, 11 waterproof connector. DETAILED DESCRIPTION

[0023] The present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the relevant invention, rather than to limit the invention. It is also necessary to explain that, for ease of description, only the parts related to the invention are shown in the accompanying drawings.

[0024] The accompanying drawings in the embodiments of the present invention: different types of section lines in the drawings are not marked according to national standards, nor do they impose requirements on the materials of the components. Instead, they are used to distinguish the cross-sectional views of the components in the drawings.

[0025] See also Figure 1-4 A fool-type capacitance level gauge comprises a probe body 2, a circuit board 3 is arranged inside the probe body 2, a bracket 5 is arranged at the lower end of the probe body 2, a probe outer tube 7 is arranged at the lower end of the bracket 5, a probe 8 is arranged inside the probe outer tube 7, a bracket 2 10 is arranged at the lower end of the probe outer tube 7, copper foil 9 is arranged inside the probe outer tube 7, five copper foils 9 with equal spacing and equal vertical length are respectively located between the inner arc surface of the probe outer tube 7 and the outer arc surface of the probe 8, an upper cover 1 is arranged at the upper end of the probe body 2, an O-ring 4 is sleeved in the groove in the middle part of the outer arc surface of the probe body 2, and a waterproof joint 11 is arranged at the threading hole of the probe body 2, and a stainless steel tube 6 is movably sleeved on the outer arc surface of the probe outer tube 7.

[0026] The upper end of the probe body 2 is an open structure.

[0027] The upper end of the stainless steel tube 6 is fixedly connected to the probe body 2 , the lower end of the stainless steel tube 6 is fixedly connected to the bracket 2 10 , and a liquid inlet hole is provided on the surface of the stainless steel tube 6 .

[0028] The stainless steel tube 6 is connected to the bracket 10 and the probe body 2 by full-circle welding, and the welding parts are polished to achieve smooth transition.

[0029] Among them, the lower end of the probe outer tube 7 is connected to the bracket 2 10 through hot melt adhesive.

[0030] The upper end of the probe body 2 is potted.

[0031] A method for calibrating a liquid level of a fool-type capacitance liquid level meter, using a fool-type capacitance liquid level meter, comprises the following steps:

[0032] Step 1, program learning: first read the zero point value of each copper foil 9, and store the zero point value permanently, then gently put the sensor into the liquid at a uniform speed, when the sensor is completely immersed in the liquid, read the capacitance value of each segment and give a prompt, and use Y=20 / (CH-CL) to calculate the transformation ratio of each segment, then lift the sensor up, and after the oil control is completed, slowly put it into the liquid again at a uniform speed, and prompt the capacitance value again. When the transformation ratios of the two times are close to and less than the X value, the learning is confirmed to be successful;

[0033] Step 2, normal liquid level measurement: the current measurement medium is the learning medium. When the medium level is in the first section and does not submerge the second section, the liquid level conversion formula of the first section is H1=Y1*(C1X-C1L), where C1X is the currently measured capacitance value, C1L is the zero capacitance value of the first section, and Y1 is the transformation ratio of the first section; when the liquid level is in the second section, the liquid level is converted by the formula H2=(Y2*(C2X-C2L))+20, and the values ​​of the third and fourth sections are obtained in the same way. The value of the fifth section is calculated by averaging the transformation ratios of the first four sections. Finally, the converted values ​​are summarized and calculated by the processing chip in the circuit board 3 to obtain the current liquid level height;

[0034] Step 3, critical point judgment: set a node size value to 20, when the next segment value is converted to 20, and the previous segment value is greater than the zero point value of the previous segment value, it is considered that the current liquid level is in the previous segment; when the next segment value is not in the current segment range position, but lower than this position, and the previous segment value has exceeded the saved zero point capacitance value, it is considered that the current liquid level is in the next segment; when the liquid level exceeds the previous segment, and the next segment value is not at the full position, the liquid level exceeds the preset threshold of the previous segment, it is considered that the current liquid level is in the previous segment;

[0035] Step 4: Liquid level calibration: When the capacitance values ​​of the first to fourth liquid levels are all greater than the zero capacitance value, and the measured values ​​of the first to third levels are less than the range capacitance value or greater than the range capacitance value, it is considered that a significant change has occurred in the medium and an updated calibration is required, which is then saved.

[0036] It should be noted that when the fool-type capacitance level meter is used, the zero point value of each copper foil 9 will be read first, and the zero point value will be permanently stored. Then the sensor will be gently and evenly placed in the liquid. When the sensor is completely immersed in the liquid, the capacitance value of each section will be read and prompted. At the same time, the transformation ratio of each section will be calculated using Y=20 / (CH-CL). Then the sensor will be lifted up. After the oil control is completed, it will be slowly and evenly placed in the liquid again to prompt the capacitance value again.

[0037] When the transformation ratio of the two times is close to and less than the X value, the learning is confirmed to be successful. The X value is obtained through multiple experiments. When the current measuring medium is the learning medium, the liquid level is converted by the calculation formula set in each section, and the converted values ​​are summarized and calculated by the processing chip in the circuit board 3 to obtain the current liquid level height;

[0038] When the capacitance values ​​of the first to fourth liquid levels are all greater than the zero capacitance value, and the measured values ​​of the first to third levels are less than the range capacitance value or greater than the range capacitance value, it is considered that a significant change has occurred in the medium and an updated calibration is required, which is then saved.

[0039] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0040] The above description is only a preferred embodiment of the present application and an explanation of the technical principles used. Those skilled in the art should understand that the scope of the invention involved in the present application is not limited to the technical solution formed by a specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the inventive concept. For example, the above features are replaced with (but not limited to) technical features with similar functions disclosed in the present application.

Claims

1. A fool-type capacitance level meter, comprising a probe body (2), characterized in that: A circuit board (3) is arranged inside the probe body (2); a bracket 1 (5) is arranged at the lower end of the probe body (2); a probe outer tube (7) is arranged at the lower end of the bracket 1 (5); a probe (8) is arranged inside the probe outer tube (7); a bracket 2 (10) is arranged at the lower end of the probe outer tube (7); copper foils (9) are arranged inside the probe outer tube (7); five copper foils (9) with equal spacing and equal vertical length are respectively located between the inner arc surface of the probe outer tube (7) and the outer arc surface of the probe (8); an upper cover (1) is arranged at the upper end of the probe body (2); an O-ring (4) is sleeved in a groove in the middle of the outer arc surface of the probe body (2); a waterproof joint (11) is arranged at the threading hole of the probe body (2); and a stainless steel tube (6) is movably sleeved on the outer arc surface of the probe outer tube (7).

2. The fool-type capacitance level meter according to claim 1 is characterized in that: The upper end of the probe body (2) is an open structure.

3. The fool-type capacitance level meter according to claim 1 is characterized in that: The upper end of the stainless steel tube (6) is fixedly connected to the probe body (2), the lower end of the stainless steel tube (6) is fixedly connected to the second bracket (10), and a liquid inlet hole is provided on the surface of the stainless steel tube (6).

4. The fool-type capacitance level meter according to claim 1 is characterized in that: The stainless steel tube (6) is connected to the second bracket (10) and the probe body (2) by full-circle welding, and the welding parts are polished to ensure smooth transition.

5. The fool-type capacitance level meter according to claim 1 is characterized in that: The lower end of the probe outer tube (7) is connected to the second bracket (10) by hot melt adhesive.

6. The fool-type capacitance level meter according to claim 1 is characterized in that: The upper end of the interior of the probe body (2) is potted.

7. A fool-type capacitance level gauge liquid level calibration method, characterized in that: A fool-type capacitance level meter according to any one of claims 1 to 8 is used, which comprises the following steps: Step 1, program learning: first read the zero point value of each copper foil (9) and store it permanently, then gently and evenly place the sensor into the liquid. When the sensor is completely immersed in the liquid, read the capacitance value of each segment and give a prompt. At the same time, use Y=20 / (CH-CL) to calculate the transformation ratio of each segment. Then lift the sensor up. After the oil control is completed, slowly and evenly place it into the liquid again. The capacitance value is prompted again. When the transformation ratios of the two times are close to and less than the X value, the learning is confirmed to be successful. Step 2, normal liquid level measurement: the current measurement medium is the learning medium. When the medium level is in the first section and does not submerge the second section, the liquid level conversion formula of the first section is H1=Y1*(C1X-C1L), where C1X is the currently measured capacitance value, C1L is the zero-position capacitance value of the first section, and Y1 is the transformation ratio of the first section. When the liquid level is in the second section, the liquid level is converted by the formula H2=(Y2*(C2X-C2L))+20. Similarly, the values ​​of the third and fourth sections are obtained. The value of the fifth section is calculated by averaging the transformation ratios of the first four sections. Finally, the converted values ​​are summarized and calculated by the processing chip in the circuit board (3) to obtain the current liquid level height. Step 3, critical point judgment: set a node size value to 20, when the next segment value is converted to 20, and the previous segment value is greater than the zero point value of the previous segment value, it is considered that the current liquid level is in the previous segment; when the next segment value is not in the current segment range position, but lower than this position, and the previous segment value has exceeded the saved zero point capacitance value, it is considered that the current liquid level is in the next segment; when the liquid level exceeds the previous segment, and the next segment value is not at the full position, the liquid level exceeds the preset threshold of the previous segment, it is considered that the current liquid level is in the previous segment; Step 4: Liquid level calibration: When the capacitance values ​​of the first to fourth liquid levels are all greater than the zero capacitance value, and the measured values ​​of the first to third levels are less than the range capacitance value or greater than the range capacitance value, it is considered that a significant change has occurred in the medium and an updated calibration is required, which is then saved.

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