A detection plate for detecting the liquid level in a liquid container and a beverage machine

Abstract

This application provides a detection plate and a beverage machine for detecting the liquid level in a liquid container, applicable to the field of beverage machine technology. The detection plate includes a substrate and a first detection circuit, a first sensing electrode plate, a second detection circuit, and a second sensing electrode plate disposed on the substrate. The first detection circuit is connected to the first sensing electrode plate, and the second detection circuit is connected to the second sensing electrode plate. Both the first and second sensing electrodes plate are arranged on the first surface of the substrate. The areas of the first and second sensing electrodes plate are different, and the area of ​​the first sensing electrode plate matches the dielectric constant of the first liquid, while the area of ​​the second sensing electrode plate matches the dielectric constant of the second liquid. The detection circuit detects the liquid level of the corresponding liquid in response to the change in the equivalent capacitance between the sensing electrode plate and the liquid container, thereby accurately detecting the liquid level changes of different liquids, providing reliable data for the control of the water pump operation process, avoiding water pump dry running, and improving the reliability of the liquid supply system and the beverage machine.

Description

Technical Field

[0001] This application relates to the field of beverage machine technology, specifically to a detection plate and a beverage machine for detecting the liquid level in a liquid container. Background Technology

[0002] In existing applications, many beverage machines (such as coffee machines) are equipped with liquid containers. By storing different liquids in the liquid containers, the beverage machines can perform different preset functions. For example, when the liquid container contains drinking water, the beverage machine can use drinking water to perform the beverage preparation function. When the liquid container contains descaling water with cleaning ingredients, the beverage machine can use the descaling water to perform the water system cleaning function.

[0003] It is understandable that the liquid pre-stored in the liquid container will gradually decrease during use, requiring the detection of the liquid level in the liquid container. The relevant technology uses a capacitive liquid level detection plate for liquid level detection, which is difficult to identify the liquid level of different liquids. This can easily lead to the problem of the water pump running dry when the liquid container is storing only one type of liquid, and may even cause abnormalities in the liquid supply system of the beverage machine. Summary of the Invention

[0004] In view of this, this application aims to provide a detection plate and a beverage machine for detecting the liquid level in a liquid container, so as to accurately detect the liquid level of different liquids in the liquid container and ensure the normal operation of the liquid supply system of the beverage machine.

[0005] In a first aspect, this application provides a detection plate for detecting the liquid level in a liquid container, wherein the liquid container can store a first liquid and a second liquid at different time periods, the dielectric constant of the first liquid being different from that of the second liquid, and the detection plate comprising: a substrate and a first detection circuit, a first sensing electrode, a second detection circuit, and a second sensing electrode disposed on the substrate, wherein...

[0006] The area of ​​the first sensing plate is different from the area of ​​the second sensing plate, and the area of ​​the first sensing plate matches the dielectric constant of the first liquid, while the area of ​​the second sensing plate matches the dielectric constant of the second liquid.

[0007] Both the first sensing electrode and the second sensing electrode are arranged on the first surface of the substrate, and the first sensing electrode is arranged away from the second sensing electrode.

[0008] The first detection circuit is connected to the first sensing electrode plate, and the second detection circuit is connected to the second sensing electrode plate;

[0009] The first detection circuit detects the liquid level of the first liquid in response to the change in the equivalent capacitance between the first sensing plate and the liquid container.

[0010] The second detection circuit detects the liquid level of the second liquid in response to the change in the equivalent capacitance between the second sensing plate and the liquid container.

[0011] In one alternative embodiment, the substrate is disposed near the outer wall of the liquid container, with the first surface facing the liquid container.

[0012] In one alternative embodiment, the dielectric constant of the first liquid is less than that of the second liquid;

[0013] The area of ​​the first sensing plate is larger than the area of ​​the second sensing plate.

[0014] In one alternative implementation, the second sensing electrode is positioned higher than the first sensing electrode in the direction of liquid level change.

[0015] In one optional embodiment, the detection board provided in the first aspect of this application further includes: a first shielding electrode plate and a second shielding electrode plate, wherein,

[0016] The first shielding plate and the second shielding plate are arranged on the second surface of the substrate, and the second surface and the first surface are two opposite surfaces of the substrate.

[0017] The first shielding plate is used to provide the first detection circuit with the function of shielding noise signals;

[0018] The second shielding plate is used to provide the second detection circuit with the function of shielding noise signals.

[0019] In one alternative embodiment, the first shielding electrode plate and the first sensing electrode plate are positioned in a direction perpendicular to the surface;

[0020] The second shielding electrode plate and the second sensing electrode plate are positioned in a direction perpendicular to the surface.

[0021] In one alternative implementation, the first shielding plate is connected to the first detection circuit, and the second shielding plate is connected to the second detection circuit.

[0022] In one optional embodiment, the first sensing electrode, the second sensing electrode, the first shielding electrode, and the second shielding electrode are all copper foils laid on the surface of the substrate.

[0023] In one alternative embodiment, the first detection circuit and the second detection circuit are constructed based on discrete components, and the discrete components of the first detection circuit and the second detection circuit are both disposed on the second surface of the substrate, the second surface and the first surface being two opposing surfaces of the substrate.

[0024] In one optional implementation, the first detection circuit and the second detection circuit include detection circuits with the same structure;

[0025] The detection circuit includes: a signal generation circuit and a signal processing circuit, wherein,

[0026] The detection terminal of the signal generation circuit is connected to the corresponding sensing plate, and the output terminal of the signal generation circuit is connected to the input terminal of the signal processing circuit.

[0027] The signal generation circuit outputs an AC signal based on the equivalent capacitance when the liquid is above the position of the sensing electrode, or outputs a DC signal based on the equivalent capacitance when the liquid is below the position of the sensing electrode.

[0028] The signal processing circuit responds to the AC signal by outputting a detection signal indicating sufficient liquid, or responds to the DC signal by outputting an alarm signal indicating the need for liquid replenishment.

[0029] In one optional implementation, the signal generation circuit includes: an oscillation circuit and a bias circuit, wherein,

[0030] The power supply terminal of the oscillation circuit receives the driving voltage signal, and the detection terminal of the oscillation circuit serves as the detection terminal of the signal generation circuit.

[0031] The bias circuit is connected between the output terminal and the feedback terminal of the oscillation circuit, providing an AC signal feedback path for the oscillation circuit.

[0032] The oscillation circuit oscillates periodically when the liquid is above the position of the sensing electrode to convert the driving voltage signal into the AC signal, or outputs the DC signal when the liquid is below the position of the sensing electrode.

[0033] In one optional implementation, the signal processing circuit includes: a voltage conversion circuit and a comparison circuit, wherein,

[0034] The voltage conversion circuit is used to convert the AC signal into a first voltage, or to convert the DC signal into a second voltage;

[0035] The comparison circuit is used to output the detection signal in response to the first voltage, or to output the alarm signal in response to the second voltage.

[0036] In one alternative implementation, the comparator circuit includes an operational amplifier;

[0037] The operational amplifier in the comparison circuit of the first detection circuit is one of the operational amplifiers in the dual-channel operational amplifier module;

[0038] The operational amplifier of the comparison circuit in the second detection circuit is another operational amplifier in the dual-channel operational amplifier module.

[0039] Secondly, this application provides a beverage machine, including a main body, a liquid container and a control module. The liquid container is used to supply liquid to the liquid pipeline in the main body. The beverage machine also includes a detection plate as provided in any embodiment of the first aspect of this application to detect the liquid level in the liquid container.

[0040] The control module is located inside the main body and connected to the detection board, and is used to receive the liquid level information detected by the detection board;

[0041] The detection plate is located between the main body and the liquid container, and the first surface of the substrate of the detection plate faces the liquid container.

[0042] In one optional embodiment, the main body is provided with a storage space for storing the liquid container;

[0043] When the liquid container is in the storage space, the liquid container is connected to the liquid pipeline and the first surface is adjacent to the outer wall of the liquid container.

[0044] In one optional implementation, the control module is configured as follows:

[0045] Based on the current operating mode of the beverage machine, the liquid level information detected by the first detection circuit or the second detection circuit in the detection board is selectively received.

[0046] Based on the above, the detection board provided in this application includes a substrate and a first detection circuit, a first sensing electrode plate, a second detection circuit, and a second sensing electrode plate disposed on the substrate. The first detection circuit is connected to the first sensing electrode plate, and the second detection circuit is connected to the second sensing electrode plate. Both the first and second sensing electrode plates are arranged on the first surface of the substrate, thereby ensuring that both the first and second sensing electrode plates can detect changes in the liquid level within the liquid container. Since the capacitance value is directly related to the electrode plate area and the dielectric constant of the insulating medium between the electrodes, the equivalent capacitance between the sensing electrode plate and the liquid container will exhibit different capacitance values ​​when different liquids are stored in the liquid container. Based on this, the areas of the first and second sensing electrode plates in this detection board are different, and the area of ​​the first sensing electrode plate matches the dielectric constant of the first liquid. The area of ​​the plate is matched with the dielectric constant of the second liquid. The first detection circuit detects the liquid level of the first liquid in response to the change in the equivalent capacitance between the first sensing plate and the liquid container. The second detection circuit detects the liquid level of the second liquid in response to the change in the equivalent capacitance between the second sensing plate and the liquid container. Thus, through the cooperation of the detection circuit and the sensing plate, the liquid level of different liquids can be detected by taking advantage of the difference between the dielectric constant of the first liquid and the dielectric constant of the second liquid. Furthermore, the first sensing plate is arranged far away from the second sensing plate, which can reduce the mutual interference between the first and second sensing plates and improve the accuracy of the liquid level detection results. Therefore, the detection plate provided in this application can accurately detect the liquid level changes of different liquids, provide reliable data for the control of the water pump operation process, avoid the water pump running dry, and improve the reliability of the liquid supply system and the beverage machine. Attached Figure Description

[0047] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0048] Figure 1 This is a schematic diagram of the structure of a detection plate provided in an embodiment of this application;

[0049] Figure 2 This is a schematic diagram showing the positional relationship between the detection plate and the liquid container provided in the embodiments of this application.

[0050] Figure 3 This is a schematic diagram of another detection plate provided in an embodiment of this application.

[0051] Figure 4 This is a schematic diagram of the second side of the detection plate provided in the embodiment of this application.

[0052] Figure 5 This is a structural block diagram of the detection circuit provided in the embodiments of this application.

[0053] Figure 6 This is a topology diagram of the detection circuit provided in the embodiments of this application.

[0054] Figure 7a This is a schematic diagram showing the positional relationship between the main body and the liquid container of a beverage machine according to an embodiment of this application.

[0055] Figure 7b This is a schematic diagram of the beverage machine provided in an embodiment of this application. Detailed Implementation

[0056] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0057] As mentioned earlier, many beverage machines are equipped with a liquid container. By storing different liquids in the liquid container, the beverage machine can achieve different preset functions. In this embodiment, taking an automatic coffee machine as an example, when drinking water is stored in the liquid container, the automatic coffee machine can automatically extract drinking water to prepare coffee, thereby realizing the beverage preparation function. When descaling water with cleaning ingredients is stored in the liquid container, the automatic coffee machine can automatically extract descaling water to achieve the cleaning function of the internal water circuit of the machine.

[0058] It is understandable that regardless of the type of liquid stored in the container, the liquid level will gradually decrease during use. Therefore, it is necessary to detect the liquid level in the container to ensure normal operation of the corresponding preset functions. The related technology uses a capacitive liquid level detection plate, which utilizes the liquid and air in the container as different dielectric materials to achieve liquid level detection. Taking the detection of the lowest water level as an example, when the drinking water level in the container drops below the position of the liquid level detection plate, the dielectric material of the equivalent capacitance formed by the liquid level detection plate and the liquid container changes from drinking water to air. This change in dielectric constant causes a change in the electrical signal of the liquid level detection plate, thereby achieving water level detection.

[0059] The inventors discovered that while this capacitive liquid level detection plate can meet the liquid level detection requirements when the liquid container stores only one type of liquid, it struggles to identify the liquid levels of different liquids stored at different times. Taking an automatic coffee machine as an example, when the coffee preparation function is activated, the liquid container contains drinking water; when the water cleaning function is activated, the liquid container contains descaling water. Drinking water and descaling water have different dielectric constants, both higher than that of air. Related technologies struggle to distinguish between drinking water and descaling water. In particular, descaling water tends to adhere to the container walls. Even if the actual level of the descaling water is lower than the position of the detection plate (i.e., in a low-level state), the high dielectric constant of the descaling water means that the equivalent capacitance will not change significantly. This leads to inaccurate detection of descaling water level changes, causing pump idling and even malfunctions in the beverage machine's liquid supply system.

[0060] To address the aforementioned issues, this application provides a detection plate for detecting changes in liquid level within a liquid container. It incorporates a sensing electrode plate matched to the dielectric constant of the liquid. Through the cooperation of the detection circuit and the sensing electrode plate, it enables the detection of liquid levels in different liquids, providing reliable data for the control of water pump operation, preventing pump dry running, and improving the reliability of the liquid supply system and beverage machine.

[0061] Based on the above, see Figure 1 As shown, the detection board provided in this embodiment includes: a substrate 10, a first detection circuit 20, a second detection circuit 30, a first sensing electrode 40, and a second sensing electrode 50, wherein the first detection circuit 20, the second detection circuit 30, the first sensing electrode 40, and the second sensing electrode 50 are all disposed on the substrate 10.

[0062] The detection board provided in this embodiment is used to detect the liquid level of the liquid stored in the liquid container. As mentioned above, in order to meet the application requirements of the beverage machine to provide different preset functions, the liquid container can store the first liquid and the second liquid at different time periods. The dielectric constant of the first liquid is different from that of the second liquid. Taking an automatic coffee machine as an example, the liquid container can store drinking water, i.e., the first liquid, in the coffee preparation mode, and correspondingly, store descaling water, i.e., the second liquid, in the water circuit cleaning mode. In this case, the dielectric constant of the first liquid is smaller than that of the second liquid.

[0063] To meet the detection requirements of different liquid levels, the area of ​​the first sensing plate 40 provided in this embodiment matches the dielectric constant of the first liquid, and the area of ​​the second sensing plate 50 matches the dielectric constant of the second liquid. As mentioned above, the dielectric constants of the first liquid and the second liquid are different; therefore, the areas of the first sensing plate 40 and the second sensing plate 50 are different. It should be noted that for any liquid with a defined dielectric constant, if the sensing plate can accurately sense the liquid level change, then the area of ​​the sensing plate can be considered to match the dielectric constant of that liquid. Of course, as will be seen later, the detection of liquid level changes requires the cooperation of the detection circuit and the sensing plate. Therefore, in practical applications, for a given detection circuit, the area of ​​the sensing plate can be continuously adjusted through multiple experiments until an area matching the dielectric constant of the liquid is determined. From another perspective, matching the area of ​​the sensing plate with the dielectric constant of the liquid can also be understood as follows: through cooperation with the detection circuit, the area of ​​the sensing plate can only accurately detect the liquid level change of a certain liquid, while it is difficult to effectively detect the liquid level change of other liquids stored in the liquid container, or the accuracy of the detection results is difficult to meet the usage requirements.

[0064] In practical applications, the first sensing electrode plate 40 and the second sensing electrode plate 50 are arranged on the same side of the substrate 10, combined with Figure 1 As shown, for ease of description, the same surface where the first sensing plate 40 and the second sensing plate 50 are located can be defined as the first surface. It is understood that, regardless of whether it is the first sensing plate 40 or the second sensing plate 50, the basic principle of detecting liquid level changes relies on the change in capacitance value of the equivalent capacitance between the sensing plate and the liquid container. Therefore, to reduce the mutual influence between the first sensing plate 40 and the second sensing plate 50, the first sensing plate 40 is arranged away from the second sensing plate 50. (See [reference]). Figure 1 As shown, with a fixed area of ​​substrate 10, the first sensing plate 40 is located on the far left of substrate 10, and the second sensing plate 50 is located on the far right of substrate 10, so that the first sensing plate 40 is arranged as far away from the second sensing plate 50 as possible. In practical applications, the first sensing plate 40 and the second sensing plate 50 can be arranged according to the specific shape and area of ​​substrate 10, which will not be described in detail here.

[0065] Furthermore, the first detection circuit 20 is connected to the first sensing plate 40, and detects the liquid level of the first liquid in response to the change in the equivalent capacitance between the first sensing plate and the liquid container. Correspondingly, the second detection circuit 30 is connected to the second sensing plate 50, and detects the liquid level of the second liquid in response to the change in the equivalent capacitance between the second sensing plate 50 and the liquid container.

[0066] The capacitance value of a capacitor can be expressed by the following formula (1):

[0067]

[0068] Where C0 represents the capacitance value of the capacitor;

[0069] ε represents the dielectric constant of the dielectric material between the capacitor plates;

[0070] S represents the electrode area;

[0071] d represents the electrode spacing.

[0072] According to formula (1), under a given application scenario, the plate area of ​​the sensing plate and the plate spacing (specifically, in this embodiment, the distance between the sensing plate and the equivalent plate corresponding to the wall of the liquid container) are determined. The parameter that affects the specific capacitance value of the equivalent capacitance between the sensing plate and the liquid container is only the dielectric constant ε. Taking the first detection circuit 20 and the first sensing plate 40 as examples, when the liquid level of the first liquid in the liquid container is higher than the position of the first sensing plate 40, the dielectric constant of the equivalent capacitance mainly depends on the first liquid. Of course, in practical applications, the container wall will also have an influence. Since the first sensing plate 40 and the second sensing plate 50 correspond to the same liquid container, the influence of the container wall can be ignored in this application. When the liquid level of the first liquid in the liquid container is lower than the position of the first sensing plate 40, the dielectric constant of the equivalent capacitance mainly depends on the air. It can be seen that the change in the liquid level of the first liquid in the liquid container will directly affect the capacitance value of the equivalent capacitance between the first sensing plate 40 and the liquid container. Based on the change in the capacitance value of the equivalent capacitance, the first detection circuit 20 can detect the liquid level of the first liquid in the liquid container. In this embodiment, the liquid level of the first liquid represents the minimum liquid level preset by the automatic coffee machine to ensure normal operation. The principle of the second detection circuit 30 and the second sensing plate 50 in detecting the change in the liquid level of the second liquid is the same, and will not be repeated here. For details on the specific process by which the first detection circuit 20 and the second detection circuit 30 achieve liquid level detection based on changes in equivalent capacitance, please refer to the relevant content in the following embodiments.

[0073] In summary, the detection board provided in this embodiment provides inductive plates for detecting the liquid levels of different liquids contained in the same liquid container at different times. The first and second inductive plates are both arranged on the first surface of the substrate, thereby ensuring that both the first and second inductive plates can detect changes in the liquid level in the liquid container. When different liquids are stored in the liquid container, the equivalent capacitance between the inductive plates and the liquid container will exhibit different capacitance values. Based on this, the area of ​​the first inductive plate in this detection board is matched with the dielectric constant of the first liquid, and the area of ​​the second inductive plate is matched with the dielectric constant of the second liquid. The detection circuit can detect the liquid level of the corresponding liquid in response to the change in the equivalent capacitance between the inductive plates and the liquid container. Thus, through the cooperation of the detection circuit and the inductive plates, the detection of the liquid level of different liquids is achieved by utilizing the fact that the dielectric constant of the first liquid is different from that of the second liquid.

[0074] Furthermore, by arranging the first sensing plate far away from the second sensing plate, the mutual interference between the first and second sensing plates can be reduced, thereby improving the accuracy of the liquid level detection results. Therefore, the detection plate provided in this application can accurately detect the liquid level changes of different liquids, providing reliable data for the control of the water pump operation process, avoiding the water pump from running dry, and improving the reliability of the liquid supply system and the beverage machine.

[0075] See Figure 2 As shown, in one optional implementation, the detection plate is disposed near the outer wall of the liquid container. As can be seen from the foregoing, the first sensing plate 40 and the second sensing plate 50 are both disposed on the first surface of the plate. Therefore, in order to reliably detect changes in liquid level, the first surface of the substrate should face the liquid container. With this arrangement, there is an equivalent capacitance Cx between the first sensing plate 40 and the liquid container, and correspondingly, there is an equivalent capacitance Cy between the second sensing plate 50 and the liquid container. Based on the foregoing, when the liquid level in the liquid container changes, each sensing plate can sense the change in liquid level immediately. Specifically, for the first liquid level detection circuit 20, when the liquid level of the first liquid is higher than the position of the first sensing plate 40, the first detection circuit 20 can output a detection signal indicating that the liquid is sufficient. When the liquid level of the first liquid is lower than the position of the first sensing plate 40, the first detection circuit 20 outputs an alarm signal indicating that liquid needs to be replenished. Correspondingly, for the second liquid level detection circuit 30, when the liquid level of the second liquid is higher than the position of the second sensing plate 50, the second detection circuit 30 also outputs a detection signal indicating that the liquid is sufficient. When the liquid level of the second liquid is lower than the position of the second sensing plate 50, the second detection circuit 30 also outputs an alarm signal indicating that liquid needs to be replenished.

[0076] Furthermore, in an optional embodiment, the first detection circuit 20 and the second detection circuit 30 are respectively constructed based on discrete devices. Since different discrete devices have different shapes, when the discrete devices are used to build corresponding detection circuits based on the copper wires laid on the substrate 10, the discrete devices will appear as follows in the direction perpendicular to the first surface of the substrate 10: Figure 2 The height variations shown indicate that, in order to bring the first sensing electrode 40 and the second sensing electrode 50 in the detection plate as close as possible to the sidewall of the liquid container, discrete components used to construct the first detection circuit 20 and the second detection circuit 30 can be disposed on the second surface of the substrate 10. Figure 2 As shown, the second surface of the substrate 10 described in this embodiment is one of the two opposing surfaces of the substrate 10, along with the aforementioned first surface. In practical applications, the first and second surfaces can be the surfaces of a PCB (Printed Circuit Board) where copper wires can be laid and discrete devices can be mounted.

[0077] As mentioned above, in the detection plate provided in this application embodiment, the area of ​​the first sensing plate is different from the area of ​​the second sensing plate, and the area of ​​the first sensing plate matches the dielectric constant of the first liquid, and the area of ​​the second sensing plate matches the dielectric constant of the second liquid. According to the capacitance value calculation formula shown in the aforementioned formula (1), the larger the area of ​​the sensing plate, the larger the capacitance value, and the higher the detection sensitivity. Based on this, when the dielectric constant of the first liquid is less than the dielectric constant of the second liquid, the area of ​​the first sensing plate is greater than the area of ​​the second sensing plate.

[0078] Specifically, taking drinking water as the first liquid and descaling water as the second liquid as an example, the dielectric constant of the descaling water is higher than that of the drinking water. When the beverage machine is in beverage preparation mode, the liquid container is used to store drinking water. As mentioned above, the capacitance value of the equivalent capacitor depends on two factors: the area of ​​the electrode plate and the dielectric constant of the dielectric material. The dielectric constant of drinking water is relatively small, so selecting a larger area for the first sensing electrode plate can ensure that the first detection circuit can accurately detect changes in the liquid level of the purified water. Correspondingly, when the beverage machine is in water cleaning mode, the liquid container is used to store descaling water. Since the dielectric constant of descaling water is relatively large, the area of ​​the second sensing electrode plate can be appropriately reduced while ensuring a significant change in the capacitance value of the equivalent capacitor Cy. This reduces the overall cost of the detection board by reducing the area of ​​the second sensing electrode plate without affecting the detection of changes in the liquid level of the descaling water by the second detection circuit. It should be noted that in practical applications, the first and second detection circuits in the detection board are continuously in detection mode after the beverage machine is powered on. The beverage machine can select the detection result of the first or second detection circuit according to the current working mode. Following the previous example, in the beverage preparation mode, the beverage machine selects the detection result of the first detection circuit to detect the change in the liquid level of drinking water in the liquid container. In the water cleaning mode, the beverage machine selects the detection result of the second detection circuit to detect the change in the liquid level of descaling water in the liquid container.

[0079] In summary, the detection board provided in this embodiment configures the area of ​​the sensing plates based on the dielectric constants of different liquids in the liquid container. When the dielectric constant of the first liquid is less than that of the second liquid, the area of ​​the first sensing plate is greater than that of the second sensing plate. With this configuration, the overall cost of the detection board can be reduced while ensuring that the detection circuit accurately detects the corresponding liquid level changes.

[0080] In practical applications, liquids with high dielectric constants are more likely to adhere to the container walls during a drop in liquid level compared to liquids with low dielectric constants. This adhered liquid affects the change in equivalent capacitance, potentially leading to a situation where the actual liquid level is below the sensing plate, but the adhered liquid results in a still relatively large equivalent capacitance, causing misidentification of the liquid level. The inventors discovered that the adhered liquid gradually peels off from top to bottom along the inner wall of the container, with higher-positioned liquids peeling off faster. Based on this, a method can be combined with… Figure 3As shown, in the direction of liquid level change, the second sensing plate 50 is positioned higher than the first sensing plate 40. When the second sensing plate 50 is used to detect the liquid level of the second liquid, even if the second liquid adheres to the wall, because the second sensing plate 50 is positioned higher, when the liquid level of the second liquid is lower than the position of the second sensing plate 50, there is still a considerable amount of the second liquid remaining in the liquid container. After the second liquid adhering to the wall is completely peeled off, the second detection circuit 30 can identify the liquid level change of the second liquid through the second sensing plate 50. This provides sufficient margin for the detection of the liquid level of the second liquid, allowing for faster detection of liquid level changes and preventing the water pump from running dry when the liquid container stores the second liquid, thus ensuring the reliability of the liquid supply system and the beverage machine.

[0081] Furthermore, this application embodiment also provides another detection plate. Based on the detection plate provided in the aforementioned embodiments, the detection plate provided in this embodiment further includes a first shielding plate and a second shielding plate. Both the first and second shielding plates are arranged on the second surface of the substrate, i.e., on the same surface as the first and second detection circuits. The shielding plates can absorb or reflect electromagnetic waves for various discrete devices connected to the substrate. Furthermore, they can cause the electric field lines of the sensing plate to converge towards the shielding plates. Without the shielding plates, the sensing plate would approximate an isolated conductor, with irregularly dispersed electric field lines, and the sensing plate would be significantly affected by electromagnetic interference. The shielding plates can suppress spatial radiation interference and conductor proximity interference, thus helping to improve the accuracy of liquid level detection. Based on this, in the detection board provided in this application embodiment, the first shielding plate is used to provide the function of shielding noise signals for the first detection circuit, and correspondingly, the second shielding plate is used to provide the function of shielding noise signals for the second detection circuit. The aforementioned first sensing plate, second sensing plate, first shielding plate, and second shielding plate are all copper foils laid on the surface of the substrate. In practical applications, PCB manufacturing technology can be used to lay the first sensing plate, second sensing plate, first shielding plate, and second shielding plate on the surface of the substrate without increasing additional hardware processing costs. In specific arrangements, the first sensing plate, second sensing plate, first shielding plate, and second shielding plate should be arranged as far as possible in a position where there are no other discrete components on the substrate to avoid the influence of the parasitic capacitance and displacement current of discrete components on the liquid level detection process.

[0082] In practical applications, the first and second shielding plates can be configured in various ways. In one optional embodiment, simply refer to the foregoing description and arrange the first and second shielding plates on the second surface of the substrate. Utilize the shielding plates' ability to suppress radiated interference in an electric field and to alter the distribution of electric field lines to provide noise signal shielding for the corresponding detection circuit.

[0083] In another optional embodiment, the relative positional relationship between the first shielding electrode and the first sensing electrode can be further defined, as well as the relative positional relationship between the second shielding electrode and the second sensing electrode. Specifically, the first shielding electrode and the first sensing electrode are positioned in a direction perpendicular to the substrate surface (i.e., the aforementioned first or second surface), and the second shielding electrode and the second sensing electrode are positioned in a direction perpendicular to the substrate surface. This arrangement can achieve directional shielding of noise signals and effectively suppress the influence of noise signals on the sensing electrode. Compared with the shielding electrode arrangement method of the aforementioned embodiment, it can greatly improve the noise signal shielding effect.

[0084] Furthermore, this application embodiment also provides a shielding plate arrangement method with the best noise signal shielding effect, see [link to relevant documentation]. Figure 4 As shown, the first shielding plate 60 and the second shielding plate 70 are shown in solid lines, and correspondingly, the first sensing plate 40 and the second sensing plate 50 are shown in dashed lines. It should be noted that, to clearly illustrate the positional relationship between the shielding plates and the sensing plates, [the following text is incomplete and requires further context]. Figure 4 In the illustrated embodiment, the inductive electrode plate and the shielding electrode plate have different external dimensions. In practical applications, as a preferred embodiment, the shielding electrode plate and the inductive electrode plate can also have the same external dimensions. That is, the first shielding electrode plate 60 and the first inductive electrode plate 40 can have exactly the same external dimensions, and the second shielding electrode plate 70 and the second inductive electrode plate 50 can have exactly the same external dimensions. The first shielding electrode plate 60 and the first inductive electrode plate 40 are positioned correspondingly in the direction perpendicular to the substrate surface, and correspondingly, the second shielding electrode plate 70 and the second inductive electrode plate 50 are positioned correspondingly in the direction perpendicular to the substrate surface. Further, in Figure 4 In the illustrated embodiment, the first shielding plate 60 is connected to the first detection circuit 20, and the second shielding plate 70 is connected to the second detection circuit 30. Compared to the shielding plate arrangement provided in any of the aforementioned embodiments, Figure 4 In the embodiment shown, the shielding plate and the sensing plate are arranged opposite to each other and the shielding plate is connected to the detection circuit. By utilizing the equipotential shielding effect and the noise cancellation mechanism, the shielding plate can achieve directional shielding of noise signals, thereby achieving a better noise signal shielding effect.

[0085] It should be noted that in the detection boards provided in the foregoing embodiments, the first detection circuit and the second detection circuit are detection circuits with the same structure. The optional implementation methods of the detection circuits are described in detail below.

[0086] See Figure 5As shown, the detection circuit provided in this application embodiment includes a signal generation circuit 100 and a signal processing circuit 200. The signal generation circuit 100 includes an oscillation circuit 110 and a bias circuit 120, and the signal processing circuit 200 includes a voltage conversion circuit 210 and a comparison circuit 220.

[0087] Combination Figure 5 As shown, the detection terminal of the oscillation circuit 110 serves as the detection terminal of the signal generation circuit 100 and is connected to the corresponding sensing plate (i.e., the aforementioned first sensing plate 40 or second sensing plate 50). The power supply terminal of the oscillation circuit 110 receives the driving voltage signal. Furthermore, the output terminal of the oscillation circuit 110 serves as the output terminal of the signal generation circuit 100 and is connected to the subsequent signal processing circuit 200.

[0088] One end of the bias circuit 120 is connected to the output terminal of the oscillation circuit 110, and the other end is connected to the feedback terminal of the oscillation circuit 110, that is, it is connected between the output terminal and the feedback terminal of the oscillation circuit 110. The bias circuit 120 is used to provide an AC signal feedback path for the oscillation circuit 110.

[0089] Based on the above connection, the oscillation circuit 110 will generate periodic oscillations when the liquid in the liquid container is higher than the position of the sensing electrode, thereby converting the obtained driving voltage signal into an AC signal. Alternatively, when the liquid in the liquid container is lower than the position of the sensing electrode, the periodic oscillation will stop and a DC signal will be output. Therefore, in the detection circuit provided in the application embodiment, the signal generation circuit 100 can output an AC signal based on the equivalent capacitance when the liquid in the liquid container is higher than the position of the sensing electrode, or output a DC signal based on the equivalent capacitance when the liquid in the liquid container is lower than the position of the sensing electrode.

[0090] When the signal generation circuit 100 outputs an AC signal, the signal processing circuit 200 outputs a detection signal indicating sufficient liquid. Alternatively, when the signal generation circuit 100 outputs a DC signal, the signal processing circuit 200 outputs an alarm signal indicating the need for liquid replenishment. Specifically, the input terminal of the voltage conversion circuit 210 serves as the input terminal of the signal processing circuit 200 and is connected to the output terminal of the signal generation circuit 100. The output terminal of the voltage conversion circuit 210 is connected to the input terminal of the comparator circuit 220, and the output terminal of the comparator circuit 220 serves as the output terminal of the signal processing circuit 200, outputting the final detection result.

[0091] Based on the foregoing, when the signal generation circuit 100 outputs an AC signal, the voltage conversion circuit 210 converts the obtained AC signal into a first voltage, and the comparison circuit 220 responds to the obtained first voltage and outputs a detection signal indicating that the liquid is sufficient. Correspondingly, when the signal generation circuit 100 outputs a DC signal, the voltage conversion circuit 210 converts the obtained DC signal into a second voltage, and the comparison circuit 220 responds to the obtained second voltage and outputs an alarm signal indicating that liquid needs to be replenished.

[0092] As mentioned above, after the beverage machine is powered on, the first detection circuit and the second detection circuit in the detection board provided in this embodiment will be continuously in the detection state. In other words, when the first liquid is stored in the liquid container, the first detection circuit outputs the aforementioned detection signal or alarm signal. Correspondingly, when the second liquid is stored in the liquid container, the second detection circuit outputs the aforementioned detection signal or alarm signal. The beverage machine selects the detection result provided by the first detection circuit or the detection result provided by the second detection circuit based on the current working mode.

[0093] Furthermore, when a shielding plate is provided, the shielding plate is connected to the output terminal of the signal generation circuit 100. As for the specific configuration of the shielding plate's location and connection method, please refer to the relevant content of the aforementioned embodiments, which will not be repeated here.

[0094] based on Figure 5 The core idea of ​​the detection circuit provided in the illustrated embodiment is further illustrated in this application by providing a different approach. Figure 6 The detection circuit shown is an optional circuit topology.

[0095] Combination Figure 6 As shown, the oscillation circuit 110 includes a first switch Q1, a second switch Q2, a first resistor R1, a second resistor R2, a third resistor, a first capacitor C1, and a second capacitor C2. The bias circuit 120 includes a fourth resistor R4, a fifth resistor R5, and a third capacitor C3.

[0096] Specifically, one end of the first resistor R1 is connected to the collector of the first switching transistor Q1, and the other end is connected to the base of the first switching transistor Q1. That is, the first resistor R1 is connected between the collector and the base of the first switching transistor Q1. Furthermore, the connection point between the first resistor R1 and the collector of the first switching transistor Q1 serves as the power supply terminal of the oscillation circuit 110, receiving the driving voltage signal. The figure shows a 5V voltage signal as an example. Of course, in practical applications, the driving voltage signal can also be a DC signal of other amplitudes. This application does not limit the specific method of providing the driving voltage signal or the specific voltage amplitude, etc. For specific implementation, please refer to relevant technologies.

[0097] The emitter of the first switch Q1 is connected to one end of the first capacitor C1, and the other end of the first capacitor C1 is connected to the base of the second switch Q2. That is, the first switch Q1 is connected to the base of the second switch Q2 through the first capacitor C1. The base of the second switch Q2 is connected to one end of the second capacitor C2, and the other end of the second capacitor C2 is grounded. That is, the base of the second switch Q2 is grounded through the second capacitor C2. The connection point between the second switch Q2 and the second capacitor C2 serves as the detection terminal of the oscillation circuit 110 and is connected to the sensing plate TB1. Based on the foregoing, the sensing plate TB1 can be either the first sensing plate or the second sensing plate.

[0098] The emitter of the second switch Q2 is connected to one end of the third resistor R3, and the other end of the third resistor R3 is grounded. That is, the emitter of the second switch Q2 is grounded through the third resistor R3. The connection point between the second switch Q2 and the third resistor R3 serves as the feedback terminal of the oscillation circuit 110 and is connected to the bias circuit 120.

[0099] One end of the second resistor R2 is connected to the emitter of the first switching transistor Q1, and the other end of the second resistor R2 is connected to the base of the second switching transistor Q2, that is, the second resistor R2 is connected in parallel with the first capacitor C1. The connection point of the first switching transistor Q1 and the first capacitor C1 serves as the output terminal of the oscillation circuit and is connected to the subsequent signal processing circuit 200.

[0100] As an optional implementation, the oscillation circuit 110 also includes a sixth capacitor C6, combined with... Figure 6 As shown, one end of the sixth capacitor C6 is connected to the power supply terminal of the oscillation circuit 110, and the other end of the sixth capacitor C6 is grounded. In practical applications, the sixth capacitor C6 can filter out the AC component in the driving voltage signal, thereby providing a more stable driving voltage signal to the oscillation circuit 110.

[0101] Furthermore, one end of the fourth resistor R4 in the bias circuit 120 is connected to the output terminal of the oscillation circuit 110, and the other end of the fourth resistor R4 is connected to one end of the fifth resistor R5. The other end of the fifth resistor R5 is grounded. One end of the third capacitor C3 is connected to the connection point of the fourth resistor R4 and the fifth resistor R5, and the other end of the third capacitor C3 is connected to the feedback terminal of the oscillation circuit 110, that is, the connection point of the second switch Q2 and the third resistor R3. Based on the aforementioned connection relationship, it can be seen that the fourth resistor R4 and the fifth resistor R5 are connected in series to form a voltage divider circuit. After the voltage signal output by the oscillation circuit 110 is processed by voltage divider, it is fed back to the oscillation circuit 110 via the third capacitor C3.

[0102] Referring to the foregoing embodiments, a shielding electrode plate can also be provided in the detection plate. Based on this, see [link to relevant documentation]. Figure 6As shown, when the shielding plate TB2 is provided, the shielding plate TB2 is connected to the output terminal of the signal generation circuit 100 and is used to provide the detection circuit with the function of shielding noise signals. The specific arrangement of the shielding plate in the detection board can be found in the relevant content of the aforementioned embodiment, and will not be repeated here.

[0103] The signal processing circuit 200 includes a voltage conversion circuit 210 and a comparator circuit 220. The voltage conversion circuit 210 includes a fourth capacitor C4, a first diode D1, a second diode D2, and a sixth resistor R6. Figure 6 As shown, one end of the fourth capacitor C4 serves as the input terminal of the signal processing circuit 200, and the other end of the fourth capacitor C4 is connected to the cathode of the first diode D1 and the anode of the second diode D2. The anode of the first diode D1 is grounded, and the cathode of the second diode D2 is connected to one end of the sixth resistor R6. The other end of the sixth resistor R6 is grounded. The connection point between the second diode D2 and the sixth resistor R6 serves as the output terminal of the voltage conversion circuit 210, which is connected to the subsequent comparator circuit 220.

[0104] It should be noted that, as an optional implementation method, in Figure 6 In the illustrated embodiment, both the first diode D1 and the second diode D2 are Schottky diodes. The unidirectional conduction characteristic of the Schottky diode is used to achieve half-wave rectification of the AC signal. Simultaneously, the short reverse recovery time and low forward voltage of the Schottky diode can meet the rectification requirements of the high-frequency AC signal output by the oscillation circuit 110, while effectively reducing the overall loss of the detection circuit. Of course, in practical applications, other types of diodes can be selected to construct the voltage conversion circuit. These will not be listed here, and all such examples, provided they do not exceed the core concept of this application, also fall within the scope of protection of this application.

[0105] In one optional implementation, the first diode D1 and the second diode D2 can be integrated into a package. After packaging, a pin is led out from the connection point between the cathode of the first diode D1 and the anode of the second diode D2, and the anode of the first diode D1 and the cathode of the second diode D2 are each led out as a pin. In other words, the device obtained after integrated packaging includes three pins. Compared with using discrete first diode D1 and second diode D2, one external pin can be reduced. Correspondingly, one solder joint can be reduced when fabricating the detection board, thereby simplifying the fabrication process of the detection board to a certain extent and improving the fabrication efficiency. Moreover, integrated packaging also helps to reduce the space occupied by the first diode D1 and the second diode D2, which helps to improve the integration of the detection board.

[0106] Furthermore, as an optional implementation, a fifth capacitor C5 is connected in parallel across the sixth resistor R6. The capacitor C5 can serve as a voltage regulator and filter, thereby providing a stable and clean voltage signal for the subsequent comparator circuit.

[0107] In another optional implementation, a third diode can be provided in the voltage conversion circuit. The anode of the third diode serves as the input terminal of the voltage conversion circuit, receiving the AC or DC signal output by the signal generation circuit. The cathode of the third diode is connected to the fourth capacitor C4. Through the voltage clamping effect of the third diode, the oscillation amplitude of the AC signal output by the signal generation circuit can be limited, thereby enhancing the anti-interference capability of the detection circuit at low liquid levels to a certain extent.

[0108] It should be noted that when the first liquid is drinking water and the second liquid is descaling water, the frequency of using descaling water for water circuit cleaning in the beverage machine is not high. In other words, the probability of the second detection circuit being subjected to high-frequency AC signal impact is low. Therefore, in practical applications, the third diode can be omitted in the second detection circuit used to detect the level of the second liquid, and it can only be set in the first detection circuit, which is used more frequently. Such differentiated settings can reduce the overall cost of the detection board to a certain extent.

[0109] The comparator circuit 220 includes a reference voltage circuit, an operational amplifier U1, and a seventh resistor R7, wherein the reference voltage circuit includes an eighth resistor R8 and a ninth resistor R9.

[0110] One end of the eighth resistor R8 serves as the input terminal of the reference voltage circuit, receiving the driving voltage. The other end of the eighth resistor R8 is connected to one end of the ninth resistor R9, and the other end of the ninth resistor R9 is grounded. The connection point of the eighth resistor R8 and the ninth resistor R9 serves as the output terminal of the reference voltage circuit. It can be understood that the eighth resistor R8 and the ninth resistor R9 are connected in series to form a voltage divider circuit. The specific voltage division ratio depends on the resistance values ​​of the eighth resistor R8 and the ninth resistor R9. The voltage divided by their series connection can divide the aforementioned driving voltage. The output voltage after voltage division is the reference voltage provided by the reference voltage circuit, which is less than the aforementioned first voltage and greater than the aforementioned second voltage. Figure 6 In the embodiment shown, the driving voltage is 5V DC voltage as an example. Of course, in practical applications, other DC voltages of different amplitudes can also be selected as driving voltages. This application does not limit the specific selection of driving voltage.

[0111] The positive input terminal of operational amplifier U1 is connected to a reference voltage circuit, and the inverting input terminal of operational amplifier U1 is connected to the output terminal of voltage conversion circuit 210. A seventh resistor R7 is connected between the positive input terminal and the output terminal of operational amplifier U1. The output terminal of operational amplifier U1 serves as the output (Out) of the detection circuit, outputting the aforementioned detection signal or alarm signal. In practical applications, voltage conversion circuit 210 can output a first voltage or a second voltage. When voltage conversion circuit 210 outputs the first voltage, operational amplifier U1 responds by outputting a detection signal indicating sufficient liquid. Alternatively, when voltage conversion circuit 210 outputs the second voltage, operational amplifier U1 responds by outputting an alarm signal indicating the need for liquid replenishment.

[0112] As can be seen from the foregoing, the first and second detection circuits are each equipped with an operational amplifier. Based on this, a dual-channel operational amplifier module can be set in the detection board. This dual-channel operational amplifier module includes two operational amplifiers that can operate independently. In practical applications, the operational amplifier of the first detection circuit in the detection board can be one of the operational amplifiers in the dual-channel operational amplifier module, and the operational amplifier of the second detection circuit can be the other operational amplifier in the dual-channel operational amplifier module. By sharing the dual-channel operational amplifier module between the first and second detection circuits, the overall cost of the detection board can be reduced while ensuring the liquid level detection accuracy of each detection circuit.

[0113] The following is combined Figure 6 The specific circuit topology shown illustrates the detailed process of the detection circuit detecting changes in liquid level.

[0114] After the detection board is powered on, the power supply terminal of the oscillation circuit 110 receives the driving voltage signal. The base of the first switching transistor Q1 receives the driving voltage signal through the first resistor R1. The base voltage of the first switching transistor Q1 increases, driving the first switching transistor Q1 to conduct. The third capacitor C3 in the bias circuit 120 provides the conduction path for the AC signal. When the liquid level is higher than the position of the sensing plate, the intermediate medium of the equivalent capacitance between the sensing plate and the liquid container is mainly liquid, and the capacitance value of the equivalent capacitance increases. The bias circuit 120 will provide a bias voltage to the emitter of the second switching transistor Q2, causing the second switching transistor Q2 to be in the off state. When the first switching transistor Q1 is fully saturated, the voltage provided to the bias circuit 120 is stable, and the bias circuit 120 no longer provides an AC signal to the second switching transistor Q2. The emitter voltage of the second switching transistor Q2 will gradually decrease, thereby causing the second switching transistor Q2 to conduct. After the second switch Q2 is saturated and turned on, the collector voltage of the second switch Q2 decreases as the emitter voltage of the second switch Q2 decreases, causing the first switch Q1 to turn off. At this time, since the first switch Q1 disconnects the connection between the second switch Q2 and the driving voltage signal, the second switch Q2 is turned off due to the lack of power drive. After the second switch Q2 is turned off, the base voltage of the first switch Q1 increases, and the first switch Q1 enters the conducting state again, thereby starting the oscillation process of the next cycle. Based on this, the signal generation circuit 100 can continuously output an AC signal when the liquid level is higher than the position of the sensing electrode. Correspondingly, when the liquid level is lower than the position of the sensing electrode, the intermediate medium of the equivalent capacitance between the sensing electrode and the liquid container will be mainly air, and the capacitance value of the equivalent capacitance will be small. The oscillation circuit 110 will not oscillate, and the signal generation circuit 100 will output a DC signal.

[0115] The signal generation circuit 100 outputs a DC or AC signal to the subsequent voltage conversion circuit 210. When the signal generation circuit 100 outputs an AC signal, the voltage conversion circuit 210 performs half-wave rectification based on the first diode D1 and the second diode D2, and further outputs a first voltage, i.e., a high level, through the sixth resistor R6. Correspondingly, when the signal generation circuit 100 outputs a DC signal, due to the characteristic of capacitors passing AC and blocking DC, the DC signal is difficult to transmit through the fourth capacitor C4, and the voltage across the sixth resistor R6 is extremely low, which can be regarded as 0V. The voltage conversion circuit 210 outputs a second voltage, i.e., a low level.

[0116] Referring to the foregoing, the comparator circuit 220 provides a reference voltage through a reference voltage circuit. This reference voltage is greater than the aforementioned second voltage and less than the aforementioned first voltage. Based on this, when the voltage conversion circuit 210 outputs the first voltage, the comparator circuit 220 outputs a low level, which is used to characterize a detection signal indicating sufficient liquid. Conversely, when the voltage conversion circuit 220 outputs the second voltage, the comparator circuit 220 outputs a high level, which is used to characterize an alarm signal indicating that liquid needs to be replenished.

[0117] It should be noted that, based on the aforementioned structure of the reference voltage circuit and its working principle of providing the reference voltage, adjusting the resistance value of the ninth resistor R9 can adjust the specific value of the reference voltage. Therefore, in practical applications, the ninth resistor R9 can be used to fine-tune the liquid level detection height after the installation position of the detection board is determined (the adjustment of the liquid level detection height mainly relies on adjusting the setting position of the detection board).

[0118] It should also be noted that the seventh resistor R7 serves as the feedback resistor at the positive input terminal of the operational amplifier U1. The larger its resistance value, the larger the hysteresis range. Here, the hysteresis range refers to the amount of liquid level change that characterizes the liquid level change of the container from a state of insufficient liquid to a state of sufficient liquid. The larger this liquid level change, the greater the anti-interference capability of the detection circuit. Of course, the hysteresis range varies for different liquids. In practical applications, the specific resistance value of the seventh resistor R7 can be selected based on the parameter configuration of each component in the oscillation circuit and the accuracy requirements of the liquid level detection.

[0119] In summary, when the liquid level is higher than the position of the sensing electrode, the equivalent capacitance between the sensing electrode and the liquid container is large, the oscillation circuit starts oscillating, the signal generation circuit outputs an AC signal, and the voltage conversion circuit responds to the obtained AC signal by outputting a first voltage. Since the first voltage is higher than the reference voltage of the comparator circuit, the comparator circuit outputs a low level to indicate that the liquid in the container is sufficient. When the liquid level is lower than the position of the sensing electrode, the equivalent capacitance between the sensing electrode and the liquid container is small, the oscillation circuit is difficult to start oscillating, the signal generation circuit outputs a DC signal, and the voltage conversion circuit responds to the obtained DC signal by outputting a second voltage. Since the second voltage is lower than the aforementioned reference voltage, the comparator circuit outputs a high level to indicate that the liquid in the container needs to be replenished. Thus, the liquid level detection in the liquid container is achieved.

[0120] Taking drinking water as the first liquid and descaling water as the second liquid as an example, the dielectric constant of descaling water is greater than that of drinking water. With the same sensing plate area, the equivalent capacitance of the liquid container storing descaling water is obviously larger, and the oscillation circuit is easier to start. Based on this, the area of ​​the second sensing plate can be reduced. With this setting, it can be ensured that the oscillation circuit of the second detection circuit can reliably start when facing descaling water, but when facing drinking water, the equivalent capacitance becomes smaller, and the oscillation circuit of the second detection circuit is difficult to start, so it cannot detect the liquid level of drinking water. This setting can not only reduce the overall cost of the detection board, but also realize the liquid level detection of different liquids.

[0121] Furthermore, based on the aforementioned working process of the oscillation circuit, it can be seen that in addition to the area of ​​the sensing plate affecting the oscillation circuit's start-up process, the parameters of other components in the oscillation circuit can also affect the start-up process. By distinguishing the parameters of the corresponding components in different detection circuits, the reliability of differential detection of different liquids can be improved, thereby meeting the liquid level detection requirements of different liquids. Specifically, this includes the following optional implementation methods.

[0122] Combination Figure 6 As shown, in one optional embodiment, the larger the capacitance value of the second capacitor C2, the easier it is for the oscillation circuit to start oscillation. Therefore, when the dielectric constant of the first liquid is less than that of the second liquid, the capacitance value of the second capacitor C2 in the first detection circuit is greater than that in the second detection circuit, thereby ensuring that the oscillation circuit of the first detection circuit is easier to start oscillation when detecting the liquid level of the first liquid and reliably detects the liquid level change of the first liquid.

[0123] In another alternative implementation, the smaller the capacitance value of the first capacitor C1, the easier it is for the oscillation circuit to start oscillating. Therefore, the capacitance value of the first capacitor C1 in the first detection circuit is smaller than the capacitance value of the first capacitor C1 in the second detection circuit, ensuring that the oscillation circuit of the first detection circuit is easier to start oscillating when detecting the liquid level of the first liquid with a relatively small dielectric constant.

[0124] In another alternative implementation, the larger the resistance value of the fifth resistor R5 in the detection circuit, the easier it is for the oscillation circuit to start oscillating. Based on this, the resistance value of the fifth resistor R5 in the first detection circuit is greater than the resistance value of the fifth resistor R5 in the second detection circuit, so as to ensure that the oscillation circuit of the first detection circuit is easier to start oscillating when detecting the liquid level of the first liquid with a relatively small dielectric constant.

[0125] Of course, in practical applications, the above-described embodiments can be combined. For example, the capacitance value of the first capacitor C1 in the first detection circuit is less than that of the first capacitor C1 in the second detection circuit, and the capacitance value of the second capacitor C2 in the first detection circuit is greater than that of the second capacitor C2 in the second detection circuit. This arrangement can further ensure that the oscillation circuit of the first detection circuit is more likely to oscillate when detecting the level of a liquid with a relatively small dielectric constant, thereby effectively distinguishing the detection sensitivity of the first and second detection circuits and meeting the level detection requirements of different liquids. Other combinations can also be used, which will not be listed here. Such combinations, without exceeding the core concept of this application, also fall within the protection scope of this application.

[0126] It should be emphasized that the detection board provided in the embodiments of this application is used to detect changes in the liquid level in a liquid container. This liquid container can store a first liquid and a second liquid at different times according to the liquid supply needs of the beverage machine. The detection board provided in this application includes two identical detection paths. By configuring a sensing electrode plate that matches the dielectric constant of the liquid, the liquid level detection of different liquids can be achieved. In actual use, after the beverage machine is powered on, the two detection paths in the detection board are continuously in a detection state. The beverage machine can select the detection result of the first detection circuit or the detection result of the second detection circuit according to the current operating mode.

[0127] Furthermore, this application also provides a beverage machine, see [link to application]. Figure 7a As shown, the beverage machine provided in this embodiment includes a main body, a liquid container, and a control module (not shown in the figure). The control module is located inside the main body. In addition, a liquid pipeline is also provided inside the main body, and the liquid container is used to supply liquid to this pipeline. Of course, the main body also includes other functional modules for beverage preparation, which will not be detailed here, but can be referred to related technologies for implementation. Compared with related technologies, the beverage machine provided in this application embodiment also includes a detection plate as provided in any of the foregoing embodiments, which detects the liquid level in the liquid container.

[0128] The control module is connected to the detection board, receives the liquid level information detected by the detection board, and combines it with... Figure 7a As shown, the main body has a storage space for accommodating liquid containers. The assembly effect of the beverage machine with the liquid containers placed within this storage space can be seen in the diagram. Figure 7b As shown, at this time, the liquid container is connected to the aforementioned liquid pipeline, the detection board is located between the main body and the liquid container, and the first surface of the substrate in the detection board faces the liquid container and is adjacent to the outer wall of the liquid container. With this arrangement, an equivalent capacitance can be formed between the sensing plates in the first detection circuit and the second detection circuit in the detection board and the liquid container.

[0129] As mentioned above, the detection board provided in this application has a first detection circuit and a second detection circuit that remain in a continuous detection state after the beverage machine is powered on. The control module can selectively receive the liquid level information detected by the first detection circuit or the second detection circuit in the detection board based on the current working mode of the beverage machine. For example, in beverage preparation mode, the control module selects the liquid level information from the first detection circuit to detect changes in the liquid level of drinking water in the liquid container; in water cleaning mode, the control module selects the liquid level information from the second detection circuit to detect changes in the liquid level of descaling water in the liquid container. After obtaining the corresponding liquid level information, the control module can further execute related control processes. For example, if the main unit is equipped with a water pump, it can drive the water pump to perform a liquid replenishment operation; or, if the main unit is not equipped with a water pump, it can issue a prompt message to remind the user to manually replenish the liquid. The specific control process can be implemented with reference to relevant technologies, and will not be detailed here.

[0130] Those skilled in the art will understand that the contents disclosed herein can be varied and modified in many ways. For example, the various devices or components described above can be implemented in hardware, or in software, firmware, or a combination of some or all of the three.

[0131] Furthermore, while this disclosure makes various references to certain elements of systems according to embodiments of this disclosure, any number of different elements may be used and operated on clients and / or servers. Elements are merely illustrative, and different aspects of the system and method may use different elements.

[0132] This disclosure uses flowcharts to illustrate the steps of a method according to embodiments of this disclosure. It should be understood that the preceding or following steps are not necessarily performed in exact order. Instead, the steps can be processed in reverse order or simultaneously. Furthermore, other operations can be added to these processes.

[0133] Those skilled in the art will understand that all or part of the steps in the above methods can be implemented by a computer program instructing related hardware, and the program can be stored in a computer-readable storage medium, such as a read-only memory. Optionally, all or part of the steps in the above embodiments can also be implemented using one or more integrated circuits. Accordingly, each module / unit in the above embodiments can be implemented in hardware or as a software functional module. This disclosure is not limited to any particular combination of hardware and software.

[0134] Unless otherwise defined, all terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains. It should also be understood that terms such as those defined in a common dictionary should be interpreted as having a meaning consistent with their meaning in the context of the relevant art, and not as having an idealized or highly formalized meaning, unless expressly defined herein.

[0135] The foregoing description is intended to illustrate the present disclosure and should not be construed as limiting it. While several exemplary embodiments of the present disclosure have been described, those skilled in the art will readily understand that many modifications may be made to the exemplary embodiments without departing from the novel teachings and advantages of the present disclosure. Therefore, all such modifications are intended to be included within the scope of the present disclosure as defined by the claims. It should be understood that the foregoing description is intended to illustrate the present disclosure and should not be construed as limiting it to the specific embodiments disclosed, and modifications to the disclosed embodiments and other embodiments are intended to be included within the scope of the appended claims. The present disclosure is defined by the claims and their equivalents.

Claims

1. A detection plate for detecting the liquid level in a liquid container, wherein the liquid container can store a first liquid and a second liquid at different time periods, the dielectric constant of the first liquid being different from that of the second liquid, characterized in that, The detection board includes: a substrate and a first detection circuit, a first sensing electrode plate, a second detection circuit, and a second sensing electrode plate disposed on the substrate, wherein... The area of ​​the first sensing plate is different from the area of ​​the second sensing plate, and the area of ​​the first sensing plate matches the dielectric constant of the first liquid, while the area of ​​the second sensing plate matches the dielectric constant of the second liquid. Both the first sensing electrode and the second sensing electrode are arranged on the first surface of the substrate, and the first sensing electrode is arranged away from the second sensing electrode. The first detection circuit is connected to the first sensing electrode plate, and the second detection circuit is connected to the second sensing electrode plate; The first detection circuit detects the liquid level of the first liquid in response to the change in the equivalent capacitance between the first sensing plate and the liquid container. The second detection circuit detects the liquid level of the second liquid in response to the change in the equivalent capacitance between the second sensing plate and the liquid container.

2. The detection plate according to claim 1, characterized in that, The substrate is disposed near the outer wall of the liquid container, and the first surface faces the liquid container.

3. The detection plate according to claim 1, characterized in that, The dielectric constant of the first liquid is less than that of the second liquid; The area of ​​the first sensing plate is larger than the area of ​​the second sensing plate.

4. The detection plate according to claim 3, characterized in that, In the direction of liquid level change, the second sensing electrode is located at a higher position than the first sensing electrode.

5. The detection plate according to claim 1, characterized in that, Also includes: The first shielding plate and the second shielding plate, wherein... The first shielding plate and the second shielding plate are arranged on the second surface of the substrate, and the second surface and the first surface are two opposite surfaces of the substrate. The first shielding plate is used to provide the first detection circuit with the function of shielding noise signals; The second shielding plate is used to provide the second detection circuit with the function of shielding noise signals.

6. The detection plate according to claim 5, characterized in that, The first shielding electrode plate and the first sensing electrode plate are positioned correspondingly in a direction perpendicular to the surface; The second shielding electrode plate and the second sensing electrode plate are positioned in a direction perpendicular to the surface.

7. The detection plate according to claim 5 or 6, characterized in that, The first shielding plate is connected to the first detection circuit, and the second shielding plate is connected to the second detection circuit.

8. The detection plate according to claim 5, characterized in that, The first sensing electrode, the second sensing electrode, the first shielding electrode, and the second shielding electrode are all copper foils laid on the surface of the substrate.

9. The detection plate according to claim 1, characterized in that, The first detection circuit and the second detection circuit are constructed based on discrete components. The discrete components of the first detection circuit and the second detection circuit are both disposed on the second surface of the substrate, and the second surface and the first surface are two opposite surfaces of the substrate.

10. The detection plate according to claim 1, characterized in that, The first detection circuit and the second detection circuit include detection circuits with the same structure; The detection circuit includes: a signal generation circuit and a signal processing circuit, wherein, The detection terminal of the signal generation circuit is connected to the corresponding sensing plate, and the output terminal of the signal generation circuit is connected to the input terminal of the signal processing circuit. The signal generation circuit outputs an AC signal based on the equivalent capacitance when the liquid is above the position of the sensing electrode, or outputs a DC signal based on the equivalent capacitance when the liquid is below the position of the sensing electrode. The signal processing circuit responds to the AC signal by outputting a detection signal indicating sufficient liquid, or responds to the DC signal by outputting an alarm signal indicating the need for liquid replenishment.

11. The detection plate according to claim 10, characterized in that, The signal generation circuit includes an oscillation circuit and a bias circuit, wherein... The power supply terminal of the oscillation circuit receives the driving voltage signal, and the detection terminal of the oscillation circuit serves as the detection terminal of the signal generation circuit. The bias circuit is connected between the output terminal and the feedback terminal of the oscillation circuit, providing an AC signal feedback path for the oscillation circuit. The oscillation circuit oscillates periodically when the liquid is above the position of the sensing electrode to convert the driving voltage signal into the alternating current signal, or outputs the direct current signal when the liquid is below the position of the sensing electrode.

12. The detection plate according to claim 10, characterized in that, The signal processing circuit includes: a voltage conversion circuit and a comparator circuit, wherein... The voltage conversion circuit is used to convert the AC signal into a first voltage, or to convert the DC signal into a second voltage; The comparison circuit is used to output the detection signal in response to the first voltage, or to output the alarm signal in response to the second voltage.

13. The detection plate according to claim 12, characterized in that, The comparator circuit includes an operational amplifier; The operational amplifier in the comparison circuit of the first detection circuit is one of the operational amplifiers in the dual-channel operational amplifier module; The operational amplifier of the comparison circuit in the second detection circuit is another operational amplifier in the dual-channel operational amplifier module.

14. A beverage machine, comprising a main body, a liquid container, and a control module, wherein the liquid container is used to supply liquid to a liquid pipeline in the main body, characterized in that, The beverage machine further includes a detection plate as described in any one of claims 1 to 13 to detect the liquid level in the liquid container; The control module is located inside the main body and connected to the detection board, and is used to receive the liquid level information detected by the detection board; The detection plate is located between the main body and the liquid container, and the first surface of the substrate of the detection plate faces the liquid container.

15. The beverage machine according to claim 14, characterized in that, The main body is provided with a storage space for storing the liquid container; When the liquid container is in the storage space, the liquid container is connected to the liquid pipeline and the first surface is adjacent to the outer wall of the liquid container.

16. The beverage machine according to claim 14, characterized in that, The control module is configured as follows: Based on the current operating mode of the beverage machine, the liquid level information detected by the first detection circuit or the second detection circuit in the detection board is selectively received.

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