Capacitive water level detection device and household appliance

Abstract

The utility model discloses a capacitive water level detection device and a household appliance, and relates to the technical field of water level detection. The device specifically comprises a liquid storage tank, and further comprises a main body and a water level detection module, the main body is provided with a base for placing the liquid storage tank, and a mounting cavity is formed in the adjacent side of the base; the water level detection module is arranged on the inner wall, close to the liquid storage tank, of the mounting cavity and comprises an electrode plate attached to the inner wall of the mounting cavity, the electrode plate and a medium in the liquid storage tank form a coupling capacitor structure, and the electrode plate is provided with a signal terminal communicated with the signal end of the controller. The base and the mounting cavity are arranged on the main body, the water level detection module is arranged on the side wall of the adjacent base, the liquid storage tank is placed on the base, an electrode plate of the water level detection module and a medium of the liquid storage tank form a coupling capacitor structure, and the liquid storage tank and the water level detection module are separated from each other. The capacitive sensor is prevented from being collided when the liquid storage tank moves, and meanwhile the accuracy of liquid level detection of the liquid storage tank is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of water level detection, in particular to a capacitive water level detection device and a household appliance. Background Art

[0002] Water level detection devices are devices used to measure the height of liquids and are widely used in water conservancy projects, environmental monitoring, industrial production, and other fields. They use different working principles to monitor water level changes and convert this data into electrical signals for output, thereby facilitating monitoring and control of liquid level changes.

[0003] The original water level monitoring methods mostly use float type, pressure type or ultrasonic type, etc. These methods have disadvantages such as easy to be polluted, high maintenance cost and limited accuracy. With the advancement of science and technology, water level monitoring technology based on capacitance principle has gradually attracted attention. The capacitance sensor unit consists of one or more pairs of capacitor plates. According to the capacitance calculation formula The capacitance formed between the plates changes with the water level, and the relative dielectric constant ε between the liquid and the electrodes changes, resulting in a change in the capacitance value.

[0004] Currently, for liquid storage tanks, it is necessary to detect the liquid level inside the liquid storage tank. Due to the limited detection range of the capacitive sensor, it needs to be attached to the side wall of the liquid storage tank, and the proximity needs to be about 1mm. This design is often used on fixed liquid storage tanks to ensure that the capacitive sensor is offset due to the movement of the liquid storage tank, so as to prevent affecting the liquid level detection of the liquid storage tank.

[0005] After the utility model owner purchased, tested and used the product, and added water to the inside of the liquid storage tank, he found that some application scenarios required moving the liquid storage tank to add water, such as a water dispenser. In this case, the water tank needs to be moved multiple times to increase the water volume. Therefore, this method will expose the capacitive sensor to the outside of the water tank. The capacitive sensor is very easy to be collided during transportation, which in turn affects the contact surface between the capacitive sensor and the liquid storage tank, causing the liquid level detection of the water tank to be prone to deviation or the liquid level of the water tank cannot be detected, affecting the accuracy of water level monitoring.

[0006] Therefore, the present application aims to avoid collision of the capacitive sensor when the water tank is moved when the water tank is taken out and water is added, while also ensuring the accuracy of the capacitive sensor in detecting the liquid level in the water tank. Utility Model Content

[0007] The main purpose of the present utility model is to provide a method for preventing a capacitive sensor from colliding when the water tank is moved when the water tank is taken out and water is added, while also ensuring the accuracy of the capacitive sensor in detecting the liquid level of the water tank.

[0008] In order to achieve the above-mentioned object, the present invention provides a capacitive water level detection device, comprising a liquid storage tank and:

[0009] A main body, provided with a base for placing the liquid storage tank, and a mounting cavity is provided on an adjacent side of the base; and

[0010] The water level detection module is arranged on the inner wall of the installation cavity near the liquid storage tank, and includes an electrode sheet attached to the inner wall of the installation cavity. The electrode sheet and the medium in the liquid storage tank form a coupling capacitor structure. The electrode sheet is provided with a signal terminal that is conductive to the controller signal end.

[0011] Furthermore, a resistor R2 is connected in series between the signal terminal and the signal end of the controller to amplify the signal strength of the coupling capacitor.

[0012] Furthermore, in a direction perpendicular to the liquid level of the liquid storage tank, the area of ​​one or both ends of the electrode sheet gradually decreases.

[0013] Furthermore, the shape of the electrode sheet is rhombus, ellipse, triangle or cone.

[0014] Furthermore, the water level detection module further includes a PCB board that is detachably mounted in the installation cavity, and the electrode sheet is located between the PCB board and the inner wall of the installation cavity.

[0015] Furthermore, the inner wall of the installation cavity is provided with a limiting strip inserted into the positioning hole of the PCB board, and a fixing cap for clamping the PCB board is provided at the end of the limiting strip.

[0016] Furthermore, the main body also includes a liquid level switch arranged on the base and connected to the liquid storage tank. A liquid level tube is connected to one end of the liquid level switch away from the liquid storage tank, and the other end of the liquid level tube extends into the installation cavity.

[0017] Furthermore, the main body also includes a bottom shell and an assembly shell that are assembled with each other, and form a space for storing the liquid level tube and the liquid level switch.

[0018] Furthermore, the base and the installation cavity are both snap-connected to the assembly shell.

[0019] The present application also discloses a household appliance, a water dispenser and a humidifier using the above-mentioned capacitive water level detection device.

[0020] The above technical solution has the following advantages:

[0021] The utility model provides a base and an installation cavity on the main body, and arranges a water level detection module on the side wall of an adjacent base, and places a liquid storage tank on the base. The electrode sheet of the water level detection module and the medium of the liquid storage tank form a coupling capacitor structure. The liquid level in the liquid storage tank can be obtained by detecting the capacitance value, and the signal is processed in the controller to separate the liquid storage tank and the water level detection module from each other. The water level detection module is hidden in the installation cavity, and when the liquid storage tank is taken out and placed for water change, the capacitive sensor can be prevented from colliding with the liquid storage tank when the liquid storage tank is moved. Since the position of the liquid storage tank is fixed each time it is taken out and placed, the accuracy of the capacitive sensor in detecting the liquid level in the liquid storage tank is also ensured. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The present invention will be described in detail below with reference to specific embodiments and accompanying drawings, wherein:

[0023] Figure 1 This is the electrical connection principle diagram of the utility model;

[0024] Figure 2 It is a structural diagram of the utility model;

[0025] Figure 3 It is a schematic diagram of the internal structure of the main body of the utility model;

[0026] Figure 4 This is a structural diagram of the utility model without the liquid storage tank;

[0027] Figure 5 It is a partial structural diagram of the utility model;

[0028] Figure 6 This is a structural diagram of the water level detection module of the utility model.

[0029] In the figure: 10, main body; 101, base; 102, assembly shell; 103, liquid level tube; 104, liquid level switch; 105, bottom shell; 106, fixing cap; 107, limit strip; 20, liquid storage tank; 30, water level detection module. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the following specific embodiments are only used to explain the present invention and do not constitute a limitation to the present invention.

[0031] like Figure 2-Figure 4 and Figure 6As shown, a capacitive water level detection device includes a liquid storage tank 20, a main body 10, and a water level detection module 30. The main body 10 is provided with a base 101 for placing the liquid storage tank 20, and a mounting cavity is provided on the adjacent side of the base 101. The water level detection module 30 is arranged on the inner wall of the mounting cavity near the liquid storage tank 20, and includes an electrode sheet attached to the inner wall of the mounting cavity. The electrode sheet and the dielectric in the liquid storage tank 20 form a coupling capacitor structure. The electrode sheet is provided with a signal terminal that is conductive to the signal terminal of the controller. The liquid storage tank 20 and the electrode sheet are separated from each other so that the electrode sheet is attached to the inner wall of the mounting cavity. When the liquid storage tank 20 is taken, there is no need to move the electrode sheet back and forth. Only the liquid storage tank 20 needs to be taken and placed. After the liquid storage tank 20 is placed on the base 101, the electrode sheet and the dielectric in the liquid storage tank 20 again form a coupling capacitor, thereby achieving the purpose of detecting the water level, preventing the water level detection module 30 from colliding when the liquid storage tank 20 is moved, and also ensuring the accuracy of the water level detection module 30 in detecting the liquid level of the liquid storage tank 20. At the same time, the water level detection module 30 is also hidden in the installation cavity to prevent the water level detection module 30 from being exposed, which would affect the appearance on the one hand and be easily damaged by accidental contact on the other hand.

[0032] Specifically, in order to ensure the liquid level in the liquid storage tank 20, the present application places the water level detection module 30 at the low position of the installation cavity, which can effectively prevent the water level in the liquid storage tank 20 from being too low, thereby achieving an alarm effect. The medium in the liquid storage tank 20 can be water, oil, sewage, etc. When the liquid storage tank 20 is placed on the base 101, the liquid outlet end of the liquid storage tank 20 is provided with a grounding end, and a coupling capacitor is formed between the electrode sheets. The liquid level in the liquid storage tank 20 can be obtained by detecting the capacitance value. This technology is a prior art and will not be described in detail here.

[0033] like Figure 1As shown, a resistor R2 is connected in series on the signal terminal and the signal end of the controller to amplify the signal strength of the coupling capacitor. Wherein, the ADC sampling circuit inputs the analog signal into the resistor R2 series circuit, and obtains the numerical value of the analog signal by measuring the voltage drop across the resistor R2. The function of the resistor R2 series circuit is to appropriately amplify or attenuate the input signal to adapt to the input range of the ADC. The specific numerical value of R2 needs to be repeatedly tested by those skilled in the art, and a certain numerical value is finally obtained to improve the signal strength of the electrode signal terminal, so that the controller can receive the signal conveniently. Since the controller is an existing product, pin 8 is connected to the water level detection module 30 through resistor R2, and the remaining ports of the controller are used for power supply, filtering of the signal, writing program and subsequent display required pins, so they are not described in detail here. Because the connection method is not unique, it can be designed according to the user's choice. In the technical solution of the present application, the electrode sheet is less than 25 mm away from the liquid storage tank 20. Through the cooperation of the above-mentioned circuit and the use of software control, the liquid level height of the liquid storage tank 20 can be detected remotely without connecting the electrode sheet to the liquid storage tank 20, thereby avoiding the electrode sheet from being picked up or falling due to collision, and also avoiding leakage of the electrode sheet, thereby increasing the service life of the electrode sheet.

[0034] like Figure 2 and Figure 3 As shown, the installation cavity is arranged parallel to the adjacent side wall of the liquid storage tank 20. The installation cavity can be at the same height as the liquid storage tank 20 or at a height lower than the liquid storage tank 20. This design can help detect the high water point of the liquid storage tank 20. When the installation cavity and the side wall of the liquid storage tank 20 are parallel, the electrode sheet of the water level detection module 30 can be arranged parallel to the side wall of the liquid storage tank 20, thereby ensuring the accuracy of the electrode sheet measurement.

[0035] like Figure 3-Figure 6 As shown, the water level detection module 30 also includes a PCB board that can be detachably assembled in the installation cavity, and the electrode sheet is located between the PCB board and the inner wall of the installation cavity. Figure 1 The circuit is arranged on a PCB board, which is assembled on the inner wall of the installation cavity as a carrier. A hole for conducting the electrode sheet is opened on the PCB board to lead out the signal terminal of the electrode sheet for connecting with the signal end of the controller. The area of ​​the electrode sheet in this application will be larger than that of the electrode sheet of the commercially available capacitive water level module, so as to improve the signal strength.

[0036] Example 1:

[0037] The inner wall of the installation cavity is provided with a limiting strip 107 that is inserted into the positioning hole of the PCB board, and a fixing cap 106 that clamps the PCB board is provided at the end of the limiting strip 107. The fixing cap 106 is clamped or screwed to the limiting strip 107 so that the fixing cap 106 blocks the PCB board, allowing the PCB board to be detachably assembled on the inner wall of the installation cavity, which is convenient for subsequent maintenance, debugging, and replacement operations.

[0038] Example 2:

[0039] A card slot is provided on the inner wall of the installation cavity, so that the PCB board can be directly stuck in the slot, thereby facilitating the disassembly and assembly of the PCB board; a bag can also be provided on the inner wall of the installation cavity, and the PCB board can be placed in the bag, which can effectively achieve a waterproof effect, thereby realizing a detachable manner.

[0040] like Figure 3 and Figure 4 As shown, the base 101 and the liquid storage tank 20 are clamped to each other, wherein the base 101 can be set as a boss, and the bottom end of the liquid storage tank 20 is recessed, so that the liquid storage tank 20 and the base 101 are clamped to each other, thereby limiting the position of the liquid storage tank 20 to avoid displacement after assembly, and also ensuring the distance between the liquid storage tank 20 and the electrode sheet, ensuring the accuracy of capacitance value detection.

[0041] The shape of the electrode sheet can be a diamond, ellipse, triangle, cone, square or circle. In order to further improve the detection effect of the electrode sheet, the area of ​​one end or both ends of the electrode sheet gradually decreases in the vertical direction of the liquid level in the liquid storage tank 20. Among them, it is preferred to use a diamond, ellipse, triangle or cone to make the area at both ends of the electrode sheet small, so that the signal reception rate at the end of the electrode sheet is low, and the middle area of ​​the electrode sheet is large, then the signal reception efficiency of the electrode sheet is high, which can improve the accuracy of the liquid level in the liquid storage tank 20, improve the consistency of the liquid level, weaken the signal at both ends of the electrode sheet, and prevent the electrode sheet from misjudgment.

[0042] like Figure 4 and Figure 5 As shown, the main body 10 also includes a liquid level switch 104 mounted on the base 101 and connected to the liquid tank 20. A liquid level tube 103 is connected to the end of the liquid level switch 104 away from the liquid tank 20. The other end of the liquid level tube 103 extends into the mounting cavity. The main body 10 also includes a bottom shell 105 and an assembly shell 102 that are assembled together to form a space for storing the liquid level tube 103 and the liquid level switch 104. Among them, the liquid level switch 104 can adopt the form of a solenoid valve or a valve. When the liquid level switch 104 is turned on, the liquid in the liquid storage tank 20 is discharged into the installation cavity through the liquid level tube 103 to realize the liquid supply operation. In order to ensure the streamlined effect of the overall structure, the bottom shell 105 and the assembly shell 102 are clamped with each other to hide the liquid level tube 103 and the liquid level switch 104, and extend into the installation cavity within the space of the liquid level tube 103 and the liquid level switch 104, making the overall design more convenient and facilitating the pipe routing operation. With the bottom shell 105 as the support seat, the base 101 and the installation cavity can be clamped on the assembly shell 102, and the base 101 and the installation cavity are arranged in the same direction of the assembly shell 102.

[0043] A household appliance, including a water dispenser, humidifier, water purifier, pipeline machine, electric water heater, coffee machine or washing machine, which uses a capacitive water level detection device. When the water dispenser or humidifier needs to be refilled with water, the liquid storage tank 20 can be removed from the main body 10, and after adding water, it can be replaced on the base 101 to ensure water level detection.

[0044] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. All equivalent structural transformations made by using the contents of the present invention specification and drawings under the utility model concept, or direct / indirect application in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A capacitive water level detection device, comprising a liquid storage tank (20), characterized in that: Also includes: The main body (10) is provided with a base (101) for placing the liquid storage tank (20), and a mounting cavity is provided on an adjacent side of the base (101); and A water level detection module (30) is arranged on the inner wall of the installation cavity near the liquid storage tank (20), and includes an electrode sheet attached to the inner wall of the installation cavity, the electrode sheet and the medium in the liquid storage tank (20) forming a coupling capacitor structure, and the electrode sheet is provided with a signal terminal connected to the controller signal terminal.

2. The capacitive water level detection device according to claim 1, wherein: In the vertical direction of the liquid level of the liquid storage tank (20), the area of ​​one end or both ends of the electrode sheet gradually decreases.

3. The capacitive water level detection device according to claim 2, wherein: The shape of the electrode sheet is rhombus, ellipse, triangle or cone.

4. The capacitive water level detection device according to claim 1, wherein: The water level detection module (30) further comprises a PCB board detachably mounted in the installation cavity, and the electrode sheet is located between the PCB board and the inner wall of the installation cavity.

5. The capacitive water level detection device according to claim 4, characterized in that: The inner wall of the installation cavity is provided with a limiting strip (107) plugged into the positioning hole of the PCB board, and a fixing cap (106) for clamping the PCB board is provided at the end of the limiting strip (107).

6. The capacitive water level detection device according to claim 1, wherein: The main body (10) further comprises a liquid level switch (104) arranged on the base (101) and connected to the liquid storage tank (20); a liquid level tube (103) is connected to one end of the liquid level switch (104) away from the liquid storage tank (20); and the other end of the liquid level tube (103) extends into the installation cavity.

7. The capacitive water level detection device according to claim 6, wherein: The main body (10) further comprises a bottom shell (105) and an assembly shell (102) which are assembled with each other and form a space for storing the liquid level tube (103) and the liquid level switch (104).

8. The capacitive water level detection device according to claim 7, wherein: The base (101) and the installation cavity are both clamped on the assembly shell (102).

9. A household appliance, characterized in that: A water dispenser, a humidifier, a water purifier, a pipeline machine, an electric water heater, a coffee machine or a washing machine using the capacitive water level detection device according to any one of claims 1 to 8.

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