A liquid level detection device and a washing machine having the same

Abstract

This invention discloses a liquid level detection device and a washing machine incorporating it. The liquid level detection device includes a first container, an air chamber, a second container, a beam emitter, and a pressure plate. The air chamber is located outside the first container and communicates with its inner cavity. The first container is filled with liquid and is also connected to the second container via a pipe. The second container has a pressure plate that can move axially within its inner cavity. An air cavity is provided on the side of the pressure plate that contacts the liquid, and a beam detection point is provided on the side of the air cavity that is away from the liquid. The beam emitter is located on the second container and emits a beam of light into the second container, which passes through the liquid and the air cavity before reaching the beam detection point. The pressure in the air chamber caused by the pressure in the air chamber displaces the liquid in the first container and flows into the second container. The water level is determined by the pressure in the air chamber based on the position of the beam reaching the beam detection point. The device has a simple structure and is easy to install. The liquid level detection device only detects the liquid level and does not participate in other actions of the washing machine, thus reducing equipment wear and tear.

Description

Technical Field

[0001] This invention belongs to the field of washing machines, and more specifically, relates to a liquid level detection device and a washing machine having the same. Background Technology

[0002] Washing machines need to detect the water level in the washing tub during washing, but existing liquid level detection devices are complex in structure and inconvenient to use.

[0003] Chinese patent application number 202120258439.X discloses a liquid level detection device and a washing machine having the same. The liquid level detection device needs to perform related action control during the washing machine's water storage and drainage while detecting the liquid level. Since it is inevitable to perform other operations besides the liquid level detection function, and the water storage and drainage actions of the washing machine occur multiple times during the washing process, the operation is inconvenient and the large number of mechanisms can easily cause equipment failure.

[0004] In view of this, the present invention is proposed. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a liquid level detection device with simple structure, convenient installation and reliable operation.

[0006] Another object of the present invention is to provide a washing machine having the above-mentioned liquid level detection device.

[0007] To solve the above-mentioned technical problems, the basic concept of the technical solution adopted by the present invention is as follows:

[0008] A liquid level detection device includes a first container, an air tank, a second container, a beam emitter, and a pressure plate.

[0009] An air bag is located outside the first container and communicates with the inner cavity of the first container; the first container is filled with liquid and is also connected to the second container through a pipe; the second container has a pressure plate in its inner cavity that can move along its axial direction, and an air cavity is provided on the side of the pressure plate that contacts the liquid, and a beam detection point is provided on the side of the air cavity that is away from the liquid; a beam emitter is provided on the second container and emits a beam into the second container, which passes through the liquid and the air cavity in sequence before being directed to the beam detection point.

[0010] By configuring an air chamber connected to the inner cavity of the first container and linking it to a second container via a pipe, liquid can be discharged from the first container and flow into the second container through the pipe when the pressure on the air chamber changes, causing its volume to decrease. Conversely, when the pressure on the air chamber changes, causing its volume to increase, liquid flowing into the second container can be returned to the first container through the pipe. When liquid is discharged from the first container into the second container, the axial thickness of the liquid in the second container increases.

[0011] A beam emitter is installed on the second container to emit a beam of light into it. The beam passes through the liquid and air chambers sequentially before reaching the beam detection point. The beam emitted by the emitter reaches the detection point at different locations due to variations in refractive index at the liquid-air interface caused by differences in liquid thickness. Logical calculations are performed based on the location of the beam detection point and the pressure exerted on the air chamber. Digital modeling is then used to establish the correspondence between the two. When the liquid level detection device is applied to the washing machine's water level detection, the relationship between the pressure exerted on the air chamber and the water level in the washing tub is calculated. This establishes the correspondence between the location of the beam detection point and the water level in the washing tub, allowing the water level in the washing tub to be determined based on the location of the beam detection point.

[0012] Furthermore, the pressure plate divides the inner cavity of the second container into two parts: a first inner cavity and a second inner cavity. The first inner cavity is connected to the first container, while the second inner cavity is isolated from the first container but connected to the outside. A spring is provided between the pressure plate and the wall of the second container, and the pressure plate can move under the action of the liquid and the spring to change the size of the first inner cavity.

[0013] As the air bag increases in pressure and decreases in volume, the liquid in the first container flows into the second container. Therefore, a pressure plate is installed in the inner cavity of the second container, dividing the inner cavity of the second container into two parts: a first inner cavity and a second inner cavity. The first inner cavity is connected to the first container, while the second inner cavity is isolated from the first container but connected to the outside. In this way, when the liquid in the first container flows into the second container, it will push the pressure plate to move, thereby increasing the liquid capacity of the first inner cavity. Since the second inner cavity of the second container is isolated from the first container but connected to the outside, the pressure plate will not be resisted by air compression when it moves.

[0014] Since it is necessary to push the liquid flowing from the first container into the second container back into the first container when the pressure outside the gas bag decreases, a power device needs to be installed in the inner cavity of the second container to provide power to move the pressure plate and compress the volume of the first inner cavity. In this invention, a spring is installed between the pressure plate and the wall of the second container. As the pressure outside the gas bag decreases, the pressure on the liquid in the first container decreases, and the pressure transmitted by the liquid to the pressure plate in the second container decreases. As a result, the pressure plate can move under the action of the spring to reduce the size of the first inner cavity and push the liquid in the second container into the first container.

[0015] Furthermore, a hole is provided on the barrel wall of the second container that forms the first inner cavity of the second container and is opposite to the pressure plate, and the beam emitter is installed in the hole.

[0016] Since a beam emitter is installed on the second container to emit a beam into the second container, the beam must pass through the liquid and air chambers in sequence before reaching the beam detection point. An air chamber is provided on the side of the pressure plate that contacts the liquid, and the beam detection point is provided on the side of the air chamber that is away from the liquid. Therefore, a hole is provided on the wall of the second container that forms the first inner cavity of the second container and is opposite to the pressure plate. The beam emitter is installed in the hole, so that the beam emitted by the beam emitter can pass through the liquid in the first inner cavity of the second container and the air chamber on the pressure plate in sequence before reaching the beam detection point.

[0017] Furthermore, the beam emitter is mounted at an angle, positioned on one side of the central axis of the second container and angled towards the other side.

[0018] Because light refracts after passing through liquids and air, in order to ensure that the light has enough space to fall on the beam detection point after refraction and does not exceed the beam detection point so that the beam detection point cannot detect the refracted light, the beam emitter must be installed at an angle. The beam emitter is installed on one side of the central axis of the second container and at an angle to the other side.

[0019] Furthermore, the beam detection point and the beam emitter are respectively located on both sides of the central axis of the second container.

[0020] As mentioned above, since light is refracted after passing through liquid and air, in order to ensure that the light has enough space to fall on the beam detection point after refraction and does not exceed the beam detection point so that the beam detection point cannot detect the refracted light, the beam detection point and the beam emitter are respectively set on both sides of the central axis of the second container, and the beam emitter is installed at an angle, with the beam emitter installed on one side of the central axis of the second container and angled to the other side. In this way, it can be ensured that the refracted light can illuminate the beam detection point.

[0021] Furthermore, a spring is provided in the second inner cavity, with both ends of the spring abutting against the pressure plate and the second container wall opposite to the pressure plate, respectively.

[0022] To facilitate installation and prevent corrosion of the spring, a spring is installed in the second inner cavity, with its two ends abutting against the pressure plate and the wall of the second container opposite the pressure plate, respectively.

[0023] Furthermore, the liquid level detection device also includes a pressure plate limiting rod. A hole is provided on the wall of the second container that forms the second inner cavity and is opposite to the pressure plate. One end of the pressure plate limiting rod is fixedly connected to the pressure plate, and the other end of the pressure plate limiting rod passes through the hole. A spring is sleeved on the outside of the pressure plate limiting rod.

[0024] To ensure the stability of the pressure plate during movement and prevent liquid leakage from the first inner cavity, the liquid level detection device also includes a pressure plate limiting rod. A hole is provided in the wall of the second container, which forms the second inner cavity and is opposite to the pressure plate. One end of the pressure plate limiting rod is fixedly connected to the pressure plate, and the other end passes through the hole. A spring is sleeved on the outside of the pressure plate limiting rod. Through the limiting action of the pressure plate limiting rod and the hole, the pressure plate will not tip over during movement, thus ensuring that the liquid in the first inner cavity does not leak.

[0025] Furthermore, the spring is a compression spring.

[0026] Since the spring is installed in the second inner cavity, and the spring needs to generate force to compress the volume of the first inner cavity, a compression spring is selected here.

[0027] The present invention also relates to a washing machine having the above-mentioned liquid level detection device, wherein the liquid level detection device is fixed below the washing tub and the air bag can contact the water at the bottom of the washing tub.

[0028] Because the liquid level detection device uses pressure changes in the air chamber to cause liquid to flow from the first container to the second container, altering the liquid thickness in the second container, the location of the light beam detection point after refraction varies, thus determining the water level in the washing tub. Therefore, the air chamber needs to be in contact with the water at the bottom of the washing tub to ensure the most accurate detection. Thus, the liquid level detection device is fixed below the washing tub, and the air chamber is in contact with the water at the bottom of the tub.

[0029] Furthermore, a hole is provided at the bottom of the washing tub, the first container is fixedly connected to the bottom of the washing tub and the bottom of the hole is sealed, and the air bag is located in the hole.

[0030] An air tank is placed in a hole at the bottom of the washing tub, allowing the water in the tub to act on it. The hole diameter is larger than the maximum diameter of the air tank. To prevent leakage, a first container is fixedly connected to the bottom of the washing tub and the bottom of the hole is sealed.

[0031] By adopting the above technical solution, the present invention has the following beneficial effects compared with the prior art.

[0032] This invention discloses a liquid level detection device and a washing machine incorporating the same. The liquid level detection device includes a first container, an air chamber, a second container, a beam emitter, and a pressure plate. The air chamber is located outside the first container and communicates with its inner cavity. The first container is filled with liquid and also communicates with the second container via a pipe. The second container has a pressure plate that can move axially within its inner cavity. An air cavity is provided on the side of the pressure plate that contacts the liquid, and a beam detection point is provided on the side of the air cavity that is away from the liquid. The beam emitter is mounted on the second container and emits a beam of light into the second container, which passes through the liquid and the air cavity before reaching the beam detection point. The pressure on the air chamber displaces the liquid in the first container, causing it to flow into the second container. This increases the thickness of the liquid in the second container along its axial direction. Because the beam emitter emits a beam of light into the second container, the beam passes through the liquid and the air cavity before reaching the beam detection point. The beam emitted by the beam emitter has different refractive indices at the liquid-air interface due to varying liquid thickness, resulting in different positions where the beam ultimately reaches the beam detection point. The pressure on the air chamber is determined based on the position of the beam at the beam detection point.

[0033] This invention also proposes a washing machine with the aforementioned liquid level detection device. By calculating the water level in the washing tub based on the pressure exerted on the air chamber, a correspondence can be established between the location of the light beam detection point and the water level in the washing tub. Thus, the water level in the washing tub can be determined based on the location of the light beam detection point. Its structure is simple, installation is easy, and the liquid level detection device only performs liquid level detection and does not participate in other actions of the washing machine, greatly reducing equipment wear and tear and avoiding the possibility of equipment failure caused by unnecessary actions.

[0034] The specific embodiments of the present invention will now be described in further detail with reference to the accompanying drawings. Attached Figure Description

[0035] The accompanying drawings, as part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments and descriptions of the invention are used to explain the invention, but do not constitute an undue limitation of the invention. Obviously, the drawings described below are merely some embodiments, and those skilled in the art can obtain other drawings based on these drawings without creative effort. In the drawings:

[0036] Figure 1 This is a schematic diagram of the installation of the liquid level detection device of the present invention on a washing machine;

[0037] Figure 2 yes Figure 1 A magnified view of a portion of the image.

[0038] Figure 3 This is a schematic diagram of the installation of the liquid level detection device on the washing machine in Embodiment 2 of the present invention;

[0039] Figure 4 yes Figure 3 A magnified view of a portion of the image.

[0040] In the diagram: 1. Washing tub; 2. First container; 3. Second container; 4. Air bag; 5. Beam emitter; 6. Air cavity; 7. Beam detection point; 8. Spring; 9. Pressure plate; 10. Second pressure plate.

[0041] It should be noted that these accompanying drawings and textual descriptions are not intended to limit the scope of the invention in any way, but rather to illustrate the concept of the invention to those skilled in the art by referring to specific embodiments. Detailed Implementation

[0042] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments will be clearly and completely described below with reference to the accompanying drawings. The following embodiments are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0043] In the description of this invention, it should be noted that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0044] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0045] Example 1

[0046] Combination Figure 1 , 2 As shown, the present invention provides a liquid level detection device, comprising a first container 2, an air tank 4, a second container 3, a beam emitter 5, and a pressure plate 9.

[0047] An air bag 4 is located outside the first container 2 and communicates with the inner cavity of the first container 2; the first container 2 is filled with liquid and is also connected to the second container 3 through a pipe; the second container 3 has a pressure plate 9 in its inner cavity that can move along its axial direction, and an air cavity 6 is provided on the side of the pressure plate 9 that is in contact with the liquid, and a beam detection point 7 is provided on the side of the air cavity 6 that is away from the liquid; a beam emitter 5 is provided on the second container 3 and emits a beam into the second container 3, which passes through the liquid and the air cavity 6 in sequence before being directed to the beam detection point 7.

[0048] By configuring an air chamber 4 connected to the inner cavity of the first container 2 externally and via a pipe to the second container 3, liquid in the first container 2 can be discharged into the second container 3 via a pipe when the pressure on the air chamber 4 changes, causing its volume to decrease. Alternatively, when the pressure on the air chamber 4 changes, causing its volume to increase, liquid flowing into the second container 3 can be returned to the first container 2 via a pipe. When liquid is discharged from the first container 2 into the second container 3, the axial thickness of the liquid in the second container 3 increases.

[0049] Because a beam emitter 5 is installed on the second container 3 to emit a beam into the second container 3, the beam passes through the liquid and air chambers 6 in sequence before reaching the beam detection point 7. The beam emitted by the beam emitter 5 reaches different positions at the beam detection point 7 due to the different refractive indices at the liquid-air interface caused by varying liquid thickness. Based on the position of the beam detection point 7 and the pressure exerted on the air chamber 4, logical calculations are performed, and digital modeling is used to establish the correspondence between the two. Then, when the liquid level detection device is applied to the washing machine water level detection, the relationship between the pressure exerted on the air chamber 4 and the water level in the washing tub 1 is calculated. This establishes the correspondence between the position of the beam detection point 7 and the water level in the washing tub 1, thus allowing the water level in the washing tub 1 to be determined based on the position of the beam detection point 7.

[0050] The pressure plate 9 divides the inner cavity of the second container 3 into two parts: a first inner cavity and a second inner cavity. The first inner cavity is connected to the first container 2, while the second inner cavity is isolated from the first container 2 but connected to the outside. A spring 8 is provided between the pressure plate 9 and the wall of the second container 3. The pressure plate 9 can move under the action of the liquid and the spring 8 to change the size of the first inner cavity.

[0051] As the air chamber 4 increases in volume and decreases in size under pressure, the liquid in the first container 2 flows into the second container 3. Therefore, a pressure plate 9 is installed in the inner cavity of the second container 3. The pressure plate 9 divides the inner cavity of the second container 3 into two parts: a first inner cavity and a second inner cavity. The first inner cavity is connected to the first container 2, while the second inner cavity is isolated from the first container 2 but connected to the outside. In this way, when the liquid in the first container 2 flows into the second container 3, it will push the pressure plate 9 to move, thereby increasing the liquid capacity of the first inner cavity. Since the second inner cavity of the second container 3 is isolated from the first container 2 but connected to the outside, the pressure plate 9 will not be resisted by air compression when it moves.

[0052] Since the liquid flowing from the first container 2 into the second container 3 needs to be pushed back into the first container 2 when the pressure on the outside of the air bag 4 decreases, a power device needs to be installed in the inner cavity of the second container 3 to provide power to move the pressure plate 9 and compress the volume of the first inner cavity. In this invention, a spring 8 is provided between the pressure plate 9 and the wall of the second container 3. As the pressure on the outside of the air bag 4 decreases, the pressure on the liquid in the first container 2 decreases, and the pressure transmitted by the liquid to the pressure plate 9 in the second container 3 decreases. As a result, the pressure plate 9 can move under the action of the spring 8 to reduce the size of the first inner cavity and push the liquid in the second container 3 into the first container 2.

[0053] A hole is provided on the barrel wall of the second container 3, which forms the first inner cavity of the second container 3 and is opposite to the pressure plate 9, and the beam emitter 5 is installed in the hole.

[0054] Since a beam emitter 5 is provided on the second container 3 to emit a beam into the second container 3, the beam must pass through the liquid and air cavity 6 in sequence before being directed to the beam detection point 7. An air cavity 6 is provided on the side of the pressure plate 9 that is in contact with the liquid, and a beam detection point 7 is provided on the side of the air cavity 6 that is away from the liquid. Therefore, a hole is provided on the wall of the second container 3 that forms the first inner cavity of the second container 3 and is opposite to the pressure plate 9. The beam emitter 5 is installed in the hole. In this way, the beam emitted by the beam emitter 5 can pass through the liquid in the first inner cavity of the second container 3 and the air cavity 6 on the pressure plate 9 in sequence before being directed to the beam detection point 7.

[0055] The beam emitter 5 is installed at an angle, on one side of the central axis of the second container 3 and at an angle to the other side.

[0056] Since light is refracted after passing through liquids and air, in order to ensure that the light has enough space to fall on the beam detection point 7 after refraction and does not exceed the beam detection point 7 so that the beam detection point 7 cannot detect the refracted light, the beam emitter 5 must be installed at an angle. The beam emitter 5 is installed on one side of the central axis of the second container 3 and at an angle to the other side.

[0057] The beam detection point 7 and the beam emitter 5 are respectively located on both sides of the central axis of the second container 3.

[0058] As described above, since light is refracted after passing through liquid and air, in order to ensure that the light has enough space to fall on the beam detection point 7 after refraction and does not exceed the beam detection point 7 so that the beam detection point 7 cannot detect the refracted light, the beam detection point 7 and the beam emitter 5 are respectively set on both sides of the central axis of the second container 3, and the beam emitter 5 is installed at an angle. The beam emitter 5 is installed on one side of the central axis of the second container 3 and at an angle to the other side. In this way, it can be ensured that the refracted light can illuminate the beam detection point 7.

[0059] A spring 8 is installed in the second inner cavity, with its two ends abutting against the pressure plate 9 and the wall of the second container 3 opposite to the pressure plate 9, respectively.

[0060] To facilitate installation and prevent corrosion of the spring 8, a spring 8 is installed in the second inner cavity. The two ends of the spring 8 abut against the pressure plate 9 and the wall of the second container 3 opposite to the pressure plate 9, respectively. Since the spring 8 is installed in the second inner cavity, and the spring 8 needs to generate force to compress the volume of the first inner cavity, a compression spring 8 is selected here.

[0061] The liquid level detection device also includes a pressure plate 9 limiting rod. The second container 3, which forms a second inner cavity and is opposite to the pressure plate 9, has a hole on its wall. One end of the pressure plate 9 limiting rod is fixedly connected to the pressure plate 9, and the other end of the pressure plate 9 limiting rod passes through the hole. The spring 8 is sleeved on the outside of the pressure plate 9 limiting rod.

[0062] To ensure the stability of the pressure plate 9 during movement and prevent liquid leakage from the first inner cavity, the liquid level detection device also includes a pressure plate 9 limiting rod. A hole is provided in the wall of the second container 3, which forms the second inner cavity and is opposite to the pressure plate 9. One end of the pressure plate 9 limiting rod is fixedly connected to the pressure plate 9, and the other end passes through the hole. A spring 8 is sleeved on the outside of the pressure plate 9 limiting rod. Through the limiting action of the pressure plate 9 limiting rod and the hole, the pressure plate 9 will not tip over during movement, thus ensuring that the liquid in the first inner cavity does not leak.

[0063] Example 2

[0064] The difference between this embodiment and Embodiment 1 is that:

[0065] Combination Figure 3-4 As shown, a second pressure plate 10 is provided in the inner cavity of the first container 2. The diameter of the second pressure plate 10 matches the inner diameter of the first container 2, and a sealing ring is provided on the outer periphery of the second pressure plate 10.

[0066] The second pressure plate 10 divides the inner cavity of the first container 2 into two parts. One part of the inner cavity is connected to the air bag and is filled with air. The other part of the inner cavity is filled with liquid and is connected to the second container through a pipe.

[0067] The second pressure plate 10 can move axially along the first container 2. In order to make the movement of the second pressure plate 10 stable, a limit rod is provided on one side of the second pressure plate 10. The limit rod is inserted into the connection port between the first container 2 and the pipeline.

[0068] When the air bag 4 is compressed, the gas enters the inner cavity of the first container 2, thereby pushing the second pressure plate 10 to move and squeezing the liquid in another part of the inner cavity of the first container 2 to be discharged outward and discharged to the second container through the pipe.

[0069] The present invention also proposes a washing machine having any of the above-mentioned liquid level detection devices, wherein the liquid level detection device is fixed below the washing tub 1, and the air bag 4 can contact the water at the bottom of the washing tub 1.

[0070] Because the pressure change of the air chamber 4 causes the liquid to flow from the first container 2 to the second container 3, altering the liquid thickness in the second container 3, the position of the light beam detection point 7 after refraction varies, thus determining the water level in the washing tub 1. Therefore, the air chamber 4 needs to be in contact with the water at the bottom of the washing tub 1 to ensure the most accurate detection. Thus, the liquid level detection device is fixed below the washing tub 1, and the air chamber 4 can contact the water at the bottom of the washing tub 1.

[0071] A hole is provided at the bottom of the washing tub 1. The first container 2 is fixedly connected to the bottom of the washing tub 1 and seals the bottom of the hole. The air bag 4 is located in the hole.

[0072] A hole is provided at the bottom of the washing tub 1, and an air bag 4 is placed in the hole to contact the water at the bottom of the washing tub 1, so that the water in the washing tub 1 can act on the air bag 4. The diameter of the hole is larger than the maximum diameter of the air bag 4. To prevent leakage, a first container 2 is fixedly connected to the bottom of the washing tub 1 and seals the bottom of the hole.

[0073] During the washing machine design phase, water is added to the washing tub 1 and the water level is detected. The air chamber 4 of the liquid level detection device is compressed, and the liquid in the first container 2 is squeezed into the second container 3. The position of the detection beam at the beam detection point is then monitored.

[0074] Logical calculations are performed based on the detected water level in washing tub 1 and the position of the light beam at the beam detection point. Using fuzzy algorithms and digital modeling, the relationship between the water level in washing tub 1 and the position of the light beam at the beam detection point is mapped, and the corresponding results are archived and written into the washing machine computer board control device.

[0075] When the user adds water to the washing tub 1, the air bag 4 of the liquid level detection device is compressed by increased pressure, and the liquid in the first container 2 flows to the second container 3. The washing machine computer board control device calculates the corresponding water level height value in the washing tub 1 based on the position of the beam at the beam detection point and displays it to the user through the display device.

[0076] This invention discloses a liquid level detection device and a washing machine incorporating the same. The liquid level detection device includes a first container, an air chamber, a second container, a beam emitter, and a pressure plate. The air chamber is located outside the first container and communicates with its inner cavity. The first container is filled with liquid and also communicates with the second container via a pipe. The second container has a pressure plate that can move axially within its inner cavity. An air cavity is provided on the side of the pressure plate that contacts the liquid, and a beam detection point is provided on the side of the air cavity that is away from the liquid. The beam emitter is mounted on the second container and emits a beam of light into the second container, which passes through the liquid and the air cavity before reaching the beam detection point. The pressure on the air chamber displaces the liquid in the first container, causing it to flow into the second container. This increases the thickness of the liquid in the second container along its axial direction. Because the beam emitter emits a beam of light into the second container, the beam passes through the liquid and the air cavity before reaching the beam detection point. The beam emitted by the beam emitter has different refractive indices at the liquid-air interface due to varying liquid thickness, resulting in different positions where the beam ultimately reaches the beam detection point. The pressure on the air chamber is determined based on the position of the beam at the beam detection point. This invention also proposes a washing machine with the aforementioned liquid level detection device. By calculating the water level in the washing tub based on the pressure exerted on the air chamber, a correspondence can be established between the location of the light beam detection point and the water level in the washing tub. Thus, the water level in the washing tub can be determined based on the location of the light beam detection point. Its structure is simple, installation is easy, and the liquid level detection device only performs liquid level detection and does not participate in other actions of the washing machine, greatly reducing equipment wear and tear and avoiding the possibility of equipment failure caused by unnecessary actions.

[0077] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-described technical content to create equivalent embodiments without departing from the scope of the present invention. The implementation schemes in the above embodiments can also be further combined or replaced. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A liquid level detection device, characterized by: Includes a first container, an air tank, a second container, a beam emitter, and a pressure plate. An air bag is located outside the first container and communicates with the inner cavity of the first container; The first container is filled with liquid, and the first container is connected to the second container through a pipe; A pressure plate is installed inside the second container, and the pressure plate can move along the axial direction of the second container. An air cavity is provided on the side of the pressure plate that contacts the liquid, and a beam detection point is provided on the side of the air cavity that is away from the liquid. The beam emitter is mounted on the second container and emits a beam into the second container. The beam passes through the liquid and air chambers in sequence before being directed to the beam detection point. The pressure plate divides the inner cavity of the second container into two parts: a first inner cavity and a second inner cavity. The first inner cavity is connected to the first container, while the second inner cavity is isolated from the first container but connected to the outside. A first hole is provided on the second container wall that forms the first inner cavity and is opposite to the pressure plate, and a beam emitter is installed in the first hole; The beam emitter is installed at an angle, on one side of the central axis of the second container and at an angle to the other side; the beam detection point and the beam emitter are respectively set on both sides of the central axis of the second container.

2. The liquid level detection device according to claim 1, characterized in that: A spring is installed between the pressure plate and the wall of the second container. The pressure plate can move under the action of the liquid and the spring to change the size of the first inner cavity.

3. A liquid level detection device according to claim 2, characterised in that: The spring is located in the second inner cavity, with its two ends abutting against the pressure plate and the second container wall opposite to the pressure plate, respectively. The spring is a compression spring.

4. The liquid level detection device according to claim 3, characterized in that: A second hole is provided on the wall of the second container that forms the second inner cavity and is opposite to the pressure plate. It also includes a pressure plate limiting rod, one end of which is fixedly connected to the pressure plate, and the other end of which passes through the second hole, with a spring sleeved on the outside of the pressure plate limiting rod.

5. A liquid level detection device according to any one of claims 1-4, characterized in that: A second pressure plate is installed in the inner cavity of the first container. The diameter of the second pressure plate matches the inner diameter of the first container. The second pressure plate divides the inner cavity of the first container into two parts. One part of the inner cavity is connected to the air bag and is filled with air. The other part of the inner cavity is filled with liquid and is connected to the second container through a pipe. A limit rod is installed on one side of the second pressure plate and is inserted into the connection port between the first container and the pipe.

6. A washing machine, characterized in that: The liquid level detection device according to any one of claims 1-5 is fixed below the washing tub, and the air bag can contact the water at the bottom of the washing tub. A third hole is provided at the bottom of the washing tub. The first container is fixedly connected to the bottom of the washing tub and seals the bottom of the third hole. The air bag is located in the third hole, and the diameter of the third hole is larger than the maximum diameter of the air bag. During the washing machine design phase, water is added to the washing tub and the water level is detected. The position of the beam at the beam detection point is also detected. Logical calculations are performed based on the detected water level in the washing tub and the position of the beam at the beam detection point. Fuzzy algorithms and digital modeling are used to establish the correspondence between the water level in the washing tub and the position of the beam at the beam detection point. The corresponding results are then archived and written into the washing machine's computer board control device. When the user adds water to the washing tub, the washing machine's computer board control device performs logical calculations and calculates the corresponding water level height in the washing tub based on the position of the light beam at the light beam detection point, and then displays and transmits this information to the user through the display device.

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