An automatic liquid level detection device based on variable dielectric constant capacitor sensor

Abstract

This utility model discloses an automatic liquid level detection device based on a variable dielectric constant capacitive sensor, relating to the field of solar photovoltaic glass technology. It includes a housing and a pipe. A groove is formed at the upper end of the housing, and electrodes are installed through the inner side walls of the groove. An amplifier is installed inside the housing, and a capacitor-to-voltage converter and an analog-to-digital converter are fixedly installed at the bottom of the housing. A microprocessor is also fixedly installed inside the housing. This utility model, by employing a variable dielectric constant capacitive sensor, can accurately detect minute changes in the dielectric constant of the solution within the pipe, achieving high-precision liquid level detection. Furthermore, through optimized design of the signal processing circuit and microprocessor, the system's anti-interference capability and stability are improved, ensuring stable operation even in complex industrial environments.

Description

Technical Field

[0001] This utility model relates to the field of solar photovoltaic glass technology, and in particular to an automatic liquid level detection device based on a variable dielectric constant capacitive sensor. Background Technology

[0002] In the photovoltaic glass coating process, the peristaltic pump is a key piece of equipment responsible for accurately delivering the coating solution. However, in actual production, due to solution consumption, pump head failure, or pipeline leaks, the silicone tubing of the peristaltic pump may experience liquid shortages. This not only affects the coating quality but can also lead to equipment damage and production interruptions. Traditional liquid level detection methods, such as float-type and ultrasonic types, suffer from insufficient accuracy and susceptibility to interference in complex industrial environments, making it difficult to meet the requirements for high-precision and high-reliability detection. Utility Model Content

[0003] The purpose of this invention is to solve the problems existing in the prior art by proposing an automatic liquid level detection device based on a variable dielectric constant capacitive sensor.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: an automatic liquid level detection device based on a variable dielectric constant capacitance sensor, comprising a housing and a pipe, wherein a groove is provided at the upper end of the housing, electrodes are installed through the inner two side walls of the groove, an amplifier is installed inside the housing, a capacitor voltage converter and an analog-to-digital converter are fixedly installed at the bottom of the housing, and a microprocessor is fixedly installed inside the housing.

[0005] Preferably, both sets of electrodes are electrically connected to an amplifier, and the amplifier is electrically connected to a capacitor-to-voltage converter.

[0006] Preferably, the capacitor voltage converter is electrically connected to the analog-to-digital converter, and the analog-to-digital converter is electrically connected to the microprocessor.

[0007] Preferably, two sets of fixing recesses are fixedly installed at the top of the inner side of the outer shell, and a limiting plate is hinged to one side of each of the two sets of fixing recesses. A long groove is opened at one end of each of the two sets of limiting plates.

[0008] Preferably, two sets of screws are fixedly installed on one side of each of the two sets of fixed recesses, and each set of screws has a nut threaded on its outer wall.

[0009] Preferably, a portion of each of the two sets of electrodes is disposed inside the two sets of fixed recesses, each pair of screws is inserted into the interior of a set of long slots, and one side of each pair of nuts is in contact with one end of a limiting plate.

[0010] Preferably, a spring-loaded latch assembly is fixedly installed at the upper end of the outer casing, and the pipe is disposed inside the groove.

[0011] Compared with the prior art, the advantages and positive effects of this utility model are as follows:

[0012] 1. High precision: By using a variable dielectric constant type capacitance sensor, it is possible to accurately sense minute changes in the dielectric constant of the solution in the pipeline, thereby achieving high-precision liquid level detection.

[0013] 2. High reliability: Through the optimized design of the signal processing circuit and microprocessor, the anti-interference ability and stability of the system are improved, ensuring stable operation even in complex industrial environments.

[0014] 3. In this utility model, the real-time capability is as follows: it can monitor the liquid level in the pipeline in real time, promptly detect and warn of liquid shortages, and provide strong protection for production safety.

[0015] 4. Ease of use: This utility model has adaptive calibration function and remote communication function, which simplifies the operation process and maintenance difficulty, and improves the ease of use of the equipment.

[0016] 5. In this utility model, the combined design of the groove and the spring bayonet assembly achieves double fixation of the pipeline, avoiding changes in the distance between the electrode and the pipeline caused by pipeline shaking, and reducing detection errors; the electrode is rigidly fixed by the fixed recess and the limiting plate, further ensuring the consistency of the detection position. Attached Figure Description

[0017] Figure 1 A three-dimensional structural diagram of an automatic liquid level detection device based on a variable dielectric constant capacitive sensor is provided for this utility model.

[0018] Figure 2 This invention presents a schematic diagram of the internal structure of an automatic liquid level detection device based on a variable dielectric constant capacitive sensor.

[0019] Figure 3 This utility model presents a sensor schematic diagram of an automatic liquid level detection device based on a variable dielectric constant capacitance sensor.

[0020] Figure 4 This invention provides a flowchart of a pipe clamping process for an automatic liquid level detection device based on a variable dielectric constant capacitance sensor;

[0021] Figure 5 This invention proposes an automatic liquid level detection device based on a variable dielectric constant capacitance sensor. Figure 2 A magnified structural diagram of A in the middle.

[0022] Legend: 1. Outer shell; 2. Groove; 3. Pipe; 4. Spring bayonet assembly; 5. Electrode; 6. Amplifier; 7. Capacitor voltage converter; 8. Analog-to-digital converter; 9. Microprocessor; 10. Fixing recess; 11. Limiting plate; 12. Long groove; 13. Screw; 14. Nut. Detailed Implementation

[0023] To better understand the above-mentioned objectives, features, and advantages of this utility model, the present utility model will be further described below with reference to the accompanying drawings and embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0024] Many specific details are set forth in the following description in order to provide a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the present invention is not limited to the specific embodiments disclosed in the following specification.

[0025] Example 1: As Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5 As shown, this utility model provides an automatic liquid level detection device based on a variable dielectric constant capacitive sensor, including a housing 1 and a pipe 3. A groove 2 is provided at the upper end of the housing 1, and electrodes 5 are installed through both sides of the inner sidewalls of the groove 2. An amplifier 6 is installed inside the housing 1. A capacitor voltage converter 7 and an analog-to-digital converter 8 are fixedly installed at the bottom of the inner side of the housing 1. A microprocessor 9 is fixedly installed inside the housing 1. Both sets of electrodes 5 are electrically connected to the amplifier 6. The amplifier 6 is electrically connected to the capacitor voltage converter 7. The capacitor voltage converter 7 is electrically connected to the analog-to-digital converter 8. The analog-to-digital converter 8 is electrically connected to the microprocessor 9.

[0026] The specific settings and functions of this embodiment are described below. The outer shell 1 serves as the main support of the device, and a groove 2 is provided at the upper end. The shape of the groove is adapted to the pipe 3 (peristaltic pump silicone tube) to embed and fix the pipe 3, ensuring the relative position of the pipe 3 and the detection component is stable.

[0027] Two sets of electrodes 5 are installed through the two side walls inside the groove 2. The electrode 5 is made of a material with excellent conductivity and stable insulation (such as gold-plated copper sheet). Its position is directly opposite the outer wall of the pipe 3, so that it can directly sense the change in dielectric constant of the medium (solution / air) inside the pipe 3.

[0028] Amplifier 6 is electrically connected to two sets of electrodes 5, receives the weak capacitance change signal induced by electrodes 5, performs pre-amplification processing, improves the signal-to-noise ratio, and provides a stable input for subsequent conversion;

[0029] The capacitor-to-voltage converter 7 (C-VConverter) is connected to the amplifier 6 and linearly converts the amplified capacitance change signal into a voltage signal, realizing the conversion of physical quantity (capacitance) into electrical signal (voltage).

[0030] The analog-to-digital converter 8 (ADC) is connected to the capacitor voltage converter 7 to convert analog voltage signals into digital signals for processing by the microprocessor 9.

[0031] The microprocessor 9 (MCU) serves as the core control unit. It receives digital signals from the analog-to-digital converter 8, compares them with preset thresholds using a built-in algorithm, determines the liquid level status, and triggers subsequent actions (such as alarms).

[0032] The circuit components (amplifier 6 → capacitor voltage converter 7 → analog-to-digital converter 8 → microprocessor 9) adopt linear electrical connections, resulting in a short signal transmission path and low interference, thus solving the problems of signal attenuation or noise interference in traditional devices.

[0033] When pipe 3 is filled with solution, the effective dielectric constant between the two electrodes 5 increases because the dielectric constant of the solution is much higher than that of air. This causes the sensor capacitance (C) to increase accordingly according to the formula (where A is the area of ​​electrode 5 and d is the distance between electrode 5). Conversely, when the solution in pipe 3 decreases or is emptied, air occupies more space, resulting in a decrease in the effective dielectric constant and a decrease in capacitance. This change in capacitance is the basis for the sensor to detect changes in liquid level.

[0034] The capacitance change signals output from the two sets of electrodes 5 are first amplified by a preamplifier 6 to improve the signal-to-noise ratio. Then, the amplified analog signal enters a special capacitor-to-voltage converter 7 (C-V Converter), which linearly converts the capacitance change into a voltage change. The converted voltage signal is then accurately converted into a digital signal by an analog-to-digital converter 8 (ADC) for further processing and analysis by a microprocessor 9 (MCU).

[0035] The microprocessor 9 (MCU) has a dedicated algorithm that determines the liquid level in pipe 3 based on the received digital signal and a preset threshold. This threshold is set according to the different types of solutions and their dielectric constant differences in experiments and practical applications. When the threshold is detected to be lower than the safety threshold, the MCU will immediately trigger the alarm system.

[0036] Example 2: Figure 1 , Figure 2 , Figure 4 and Figure 5As shown, a spring-loaded bayonet assembly 4 is fixedly installed on the upper end of the outer shell 1. The pipe 3 is located inside the groove 2. Two sets of fixing recesses 10 are fixedly installed at the top of the inner part of the outer shell 1. A limiting plate 11 is hinged to one side of each of the two sets of fixing recesses 10. A long groove 12 is opened at one end of each of the two sets of limiting plates 11. Two sets of screws 13 are fixedly installed on one side of each of the two sets of fixing recesses 10. A nut 14 is threaded on the outer wall of each set of screws 13. Parts of the two sets of electrodes 5 are respectively located inside the two sets of fixing recesses 10. Each pair of screws 13 is inserted into the inside of a set of long grooves 12. One side of each pair of nuts 14 is in contact with one end of a limiting plate 11 on one side.

[0037] The overall effect of this embodiment is that the combined design of the groove 2 and the spring bayonet assembly 4 achieves double fixation of the pipe 3, preventing the distance between the electrode 5 and the pipe 3 from changing due to the shaking of the pipe 3, and reducing detection errors; the electrode 5 is rigidly fixed by the fixing recess 10 and the limiting plate 11, further ensuring the consistency of the detection position.

[0038] The spring-loaded bayonet assembly 4 is installed on the upper end of the housing 1. It clamps the pipe 3 with the elastic tension of the spring, further fixing the position of the pipe 3 and preventing the relative distance between the electrode 5 and the pipe 3 from changing due to vibration or displacement of the pipe 3, thus ensuring detection stability.

[0039] The top of the inner shell 1 is provided with two sets of fixed recesses 10, and the connecting end of the electrode 5 is placed in the recesses; a limiting plate 11 is hinged to one side of the recess, and a long slot 12 is opened at one end of the limiting plate 11. Two sets of screws 13 pass through the long slot 12 and are fixed to the fixed recesses 10. The limiting plate 11 is locked by the nut 14 to achieve precise positioning and anti-loosening of the electrode 5.

[0040] The limiting plate 11 is locked by the cooperation of the nut 14 and the screw 13, which facilitates the replacement or calibration of the electrode 5 in the future and reduces maintenance costs.

[0041] The device's operation and working principle are as follows: A 24V DC voltage is input, which is then stepped down to generate 3.3V to power the chip inside the sensor. A transient voltage suppressor diode (TVS) is connected in parallel at the power input for overvoltage protection, along with a reverse connection protection diode. A 100Ω resistor is connected in series for voltage division protection. Figure 3 The left side of the microcontroller is the output signal control section, which ultimately controls the 2N7002 field-effect transistor. The right side is the detection section, which uses two pins of the microcontroller as output and input. P2.7 (PWM signal output terminal) generates a high-frequency oscillation signal that passes through the detection circuit, which consists of a subtractor composed of operational amplifier 6. When liquid approaches, the capacitance at the output terminal increases, and the two signals input to interfaces 3 and 4 of operational amplifier 6 generate a phase difference. The final difference value is output and then filtered back to the microcontroller.

[0042] The above are merely preferred embodiments of this utility model and are not intended to limit the utility model in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments for application in other fields. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of this utility model without departing from the technical solution of this utility model shall still fall within the protection scope of this utility model.

Claims

1. An automatic detection liquid level device based on a variable dielectric constant type electric capacitance sensor, comprising a housing (1) and a pipe (3), characterized in that: The upper end of the outer shell (1) is provided with a groove (2), and electrodes (5) are installed through both sides of the inner sidewalls of the groove (2). An amplifier (6) is installed inside the outer shell (1). A capacitor voltage converter (7) and an analog-to-digital converter (8) are fixedly installed at the bottom of the inner side of the outer shell (1). A microprocessor (9) is fixedly installed inside the outer shell (1).

2. The automatic liquid level detection device based on the variable dielectric constant type capacitive sensor according to claim 1, characterized in that: Both sets of electrodes (5) are electrically connected to the amplifier (6), which is electrically connected to the capacitor voltage converter (7).

3. The automatic liquid level detection device based on a variable dielectric constant capacitance sensor according to claim 2, characterized in that: The capacitor voltage converter (7) is electrically connected to the analog-to-digital converter (8), and the analog-to-digital converter (8) is electrically connected to the microprocessor (9).

4. The automatic liquid level detection device based on the variable dielectric constant type capacitive sensor according to claim 1, characterized in that: Two sets of fixing recesses (10) are fixedly installed at the top of the inner side of the outer shell (1). One side of each of the two sets of fixing recesses (10) is hinged to a limiting plate (11), and one end of each of the two sets of limiting plates (11) is provided with a long groove (12).

5. The automatic liquid level detection device based on the variable dielectric constant type capacitive sensor according to claim 4, characterized in that: Two sets of screws (13) are fixedly installed on one side of each of the two sets of fixed recesses (10), and each set of screws (13) has a nut (14) threaded on its outer wall.

6. The automatic liquid level detection device based on the variable dielectric constant type capacitive sensor according to claim 5, characterized in that: A portion of each of the two sets of electrodes (5) is respectively disposed inside the two sets of fixed recesses (10), each set of two sets of screws (13) is inserted into the interior of a set of long slots (12), and one side of each set of nuts (14) is in contact with one end of a limiting plate (11).

7. The automatic liquid level detection device based on the variable dielectric constant type capacitive sensor according to claim 1, characterized in that: A spring-loaded bayonet assembly (4) is fixedly installed on the upper end of the outer shell (1), and the pipe (3) is set inside the groove (2).

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