Level meter

Abstract

The utility model discloses a level meter which comprises a frequency generator, an amplifier and a coil, the output end of the frequency generator is connected with one end of the coil through the amplifier, the other end of the coil is in contact with the surrounding environment of an object to be detected, and the surrounding environment of the object to be detected is equivalent to a capacitor. The capacitance value of the capacitor is related to the dielectric constant of the surrounding environment of the object to be detected; the capacitor and the coil generate an LC oscillation circuit, and the resonant frequency generated by the LC oscillation circuit is compared with a trigger threshold value to realize early warning.

Description

Technical Field

[0001] This utility model belongs to the field of measurement technology, specifically relating to a level gauge. Background Technology

[0002] Existing level gauges suffer from problems such as difficulty in calibration, susceptibility to adhesion, and limited detection materials (e.g., only liquids), and have a relatively limited range of applications. Utility Model Content

[0003] Purpose of the utility model: In order to solve the problems of difficult calibration and susceptibility to adhesion of existing level gauges, as well as the problems of limited detection materials and limited application scope of existing level gauges, this utility model proposes a level gauge.

[0004] Technical solution: A level gauge includes a frequency generator, a coil, a microcontroller, and an alarm circuit. The output terminal of the frequency generator is connected to one end of the coil, and the other end of the coil contacts the surrounding environment of the object to be detected. The surrounding environment of the object to be detected is equivalent to a capacitor, and the capacitance value of the capacitor is related to the dielectric constant of the surrounding environment. The equivalent capacitor and the coil form an LC oscillation circuit. The microcontroller is connected to the LC oscillation circuit and is used to obtain the resonant frequency generated by the LC oscillation circuit. The output terminal of the microcontroller is connected to the alarm circuit.

[0005] Furthermore, it also includes an amplifier, the output of which is connected to one end of the coil via the amplifier.

[0006] Furthermore, the frequency generator outputs a fixed frequency.

[0007] Furthermore, the capacitance value of the equivalent capacitor is expressed as:

[0008]

[0009] In the formula, ε is the dielectric constant of the environment surrounding the object to be tested, A represents the relative area between the two electrodes of the capacitor, and d represents the distance between the two electrodes of the capacitor.

[0010] Beneficial effects: Compared with the prior art, this utility model has the following advantages:

[0011] (1) The level gauge of this utility model adopts radio frequency admittance technology, which effectively solves the problems of difficult calibration and susceptibility to adhesion of traditional level gauges, and greatly improves the stability of measurement;

[0012] (2) The level gauge of this utility model has the advantages of strong anti-interference ability and stable and reliable measurement;

[0013] (3) The level gauge of this utility model can realize the visual adjustment of parameters, has a wider range of applications, and can detect liquids as well as water-solid mixtures, that is, there are floating objects in the water.

[0014] (4) The level gauge of this utility model can better overcome the measurement error caused by material hanging, because the dielectric constant of the hanging material has not reached the dielectric constant value for alarm response, so it is not affected by viscosity and is suitable for high viscosity conditions.

[0015] (5) The ambient temperature range of the level gauge of this utility model is -40-80℃, which is less affected by the ambient temperature, and therefore has a wider range of applications. Attached Figure Description

[0016] Figure 1 This is the circuit diagram of the level gauge proposed in this utility model. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to specific embodiments and accompanying drawings. It should be understood that these descriptions are merely exemplary and not intended to limit the scope of this utility model.

[0018] like Figure 1 As shown, this embodiment proposes a level gauge, including a frequency generator, an amplifier, and a coil L. The output of the frequency generator is connected to one end of the coil L through the amplifier. The other end of the coil L contacts the surrounding environment of the object to be detected. The surrounding environment of the object to be detected forms a capacitor, and the capacitance value of the capacitor is linked to the dielectric constant (DK value) of the surrounding environment. The capacitor and the coil L generate an LC oscillation circuit. The resonant frequency generated by the LC oscillation circuit is sent to a microcontroller for processing. In the microcontroller, the obtained resonant frequency is compared with a trigger threshold to obtain a comparison result. Based on the comparison result, a control signal is generated, and the microcontroller sends the control signal to a subsequent alarm circuit, which includes, but is not limited to, an indicator light or a buzzer.

[0019] The equivalent model and measurement working principle of the level gauge proposed in this embodiment are illustrated below:

[0020] The inherent frequency f0 of the frequency generator varies within the range of 100MHz-180MHz; the alarm setting value is 128MHz.

[0021] In actual measurement, the dielectric constant changes in two ways:

[0022] Scenario 1: For a single medium, the mixing ratio of air and medium varies with the probe insertion depth, resulting in changes in ε.

[0023] Scenario 2: Changes in the medium itself lead to changes in ε.

[0024] For scenario one:

[0025] Due to capacitance value In the formula, ε is the dielectric constant of the measured medium. As the sewage overflows the probe, ε increases from small to large, and the capacitance value C also increases accordingly.

[0026] The resonant frequency generated by the LC resonant circuit is expressed as:

[0027]

[0028] As sewage overflows the probe, ε increases from small to large, and the capacitance value C also increases accordingly. The resonant frequency f decreases from large to small. When the resonant frequency f is less than the alarm setting value, an alarm is triggered.

Claims

1. A level gauge, characterized in that: The device includes a frequency generator, a coil, a microcontroller, and an alarm circuit. The output of the frequency generator is connected to one end of the coil, and the other end of the coil contacts the surrounding environment of the object to be detected. The surrounding environment is equivalent to a capacitor, and the capacitance value of the capacitor is related to the dielectric constant of the surrounding environment. The equivalent capacitor and the coil form an LC oscillation circuit. The microcontroller is connected to the LC oscillation circuit and is used to obtain the resonant frequency generated by the LC oscillation circuit. The output of the microcontroller is connected to the alarm circuit.

2. The level gauge according to claim 1, characterized in that: It also includes an amplifier, the output of which is connected to one end of a coil via the amplifier.

3. A level gauge according to claim 1, characterized in that: The frequency generator outputs a fixed frequency.

4. A level gauge according to claim 1, characterized in that: The capacitance of the equivalent capacitor is expressed as: In the formula, ε is the dielectric constant of the environment surrounding the object to be tested, A represents the relative area between the two electrodes of the capacitor, and d represents the distance between the two electrodes of the capacitor.

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