Water level sensor, water measuring device and electric appliance formed by water level sensor and water measuring device

Abstract

The utility model relates to a water level sensor, a water measuring device and an electric appliance formed by the same, which are characterized in that the water level is measured by using the change of corresponding capacitance induced voltage when the water level approaches but does not touch or touches a water level probe and is free of water or far away from water by a certain distance. A water level probe of the sensor and the device is connected with one end of a capacitor in series through a wire, the other end of the capacitor is connected with a touch sensing signal input end of a computer measurement and control instrument with a touch sensing signal input interface end to form a water level detection branch, and a computer measures the water level, the water capacity or the flow in real time according to signal state changes of the computer. Compared with the prior art, the device for measuring water has the advantages of scaling prevention, electric shock prevention, safety, reliability, small size, low cost and long service life.

Description

Technical Field

[0001] The utility model relates to water detection technology, in particular to a water level sensor, a water measuring device and an electrical appliance formed thereby. Background Art

[0002] Water level detection is often used in daily life. The most commonly used ones are non-contact ultrasonic liquid level sensors, Hall element electromagnetic induction liquid level sensors, reed switch float sensors and electrode water level sensors made based on the good conductivity (low resistance) of ordinary water, such as boilers, water towers, wine tanks, etc.

[0003] There are many problems with the devices for measuring water in the prior art, such as: 1. The problems of non-contact ultrasonic liquid level sensors, Hall element electromagnetic induction liquid level sensors, and reed switch float sensors are high cost, large size, and greatly restricted by the application environment. They need to be customized, and the customization time is long. They cannot be used in some small application spaces, high temperatures, and closed places, especially in places with low cost requirements. For example, they are not applicable to beverage machines and tea stoves. In particular, the float sensor has a minimum draft line, so it cannot float if there is less water, and the residual liquid cannot be measured and always remains, causing waste or pollution. The devices for measuring water in the prior art, including ordinary electrode-type water level (liquid level) probes made of metal rods, are impossible to use on electric teapots. Not only are they difficult to clean, but they are also too small to fit in the inner cavity of the electric teapot. High temperature and high humidity water vapor affect the reliability of detection, and scale will also cause frequent failure of detection, and food hygiene and safety cannot be met. 2. The common electrode-type water level (liquid level) probe made of metal rods has many insurmountable defects because it uses the conductivity of the electrode, water resistance and the applied DC voltage to measure the water level: 1. Due to the small water resistance, it is difficult to distinguish the water level in the circuit when low cost, few signal connection lines and multi-level water level detection are required, resulting in unreliable measurement; 2. Applying DC voltage to the electrode will form an electric field between it and the grounding electrode, which not only ionizes the water, but also causes serious scaling and rusting of the electrode. In this way, not only will the soluble minerals in the water crystallize into scale and float on the water surface or adhere to the electrode, but the conductivity of the scale is unstable, which often leads to system failure and failure to measure the water level, which in turn causes the entire application system to fail to detect and cause serious accidents.

[0004] The existing water level detection device still has some disadvantages: 1. Many places do not have the conditions to frequently change batteries, nor do they have the conditions to use solar cells, so safe batteries cannot be used for power supply. 2. The most convenient way is to use AC power frequency power supply, that is, to rectify the high-voltage and strong-current 220V AC power supply into a low-voltage power supply, such as a 24V DC power supply. This creates new problems. Many water level detection devices are used in water-related electrical appliances (such as tea stoves, boilers, water dispensers, etc.). Anti-electric shock is a mandatory requirement of national and international standards. Products that do not meet the standards cannot be produced. If a general strong-current isolation device is added, not only will the volume increase greatly, but there is often no space to place the strong-current isolation device. This leads to the fact that some water containers of water-related electrical appliances cannot be equipped with water level detection devices, such as kung fu tea stoves, tea art stoves, health electric kettles, etc., and can only use timing control. At present, tea stoves with electrode-type high and low water level control are rare on the market, and even if there are, they are not in compliance with safety regulations and often fail to detect. Utility Model Content

[0005] A basic task of the utility model is to provide a new sensor for detecting water level (including water-containing liquid level), so that the water level detection device manufactured based on this sensor is not only low in cost, small in size, and easy to produce, but also its probe is not easy to electrolyze, rust, and scale, and is particularly suitable for closed, humid, high-temperature, short-time high and low temperature changes, and narrow space occasions.

[0006] A further task of the utility model is to provide a device for detecting water level (including water-containing liquid level) with low cost, simple circuit and safe isolation of strong and weak electricity.

[0007] A further task of the utility model is to provide several electrical appliances with water level measurement function based on the sensor principle of the utility model.

[0008] The task of the utility model is achieved through the following technical solutions:

[0009] A water level sensor comprises a water level probe as a signal sensing end. The water level probe is made of elastic or rigid metal material and is connected in series with a capacitor through a wire to form a basic water level detection branch.

[0010] Further optimization measures include:

[0011] The total withstand voltage of the capacitor is greater than or equal to 400V, 600V, 800V, 1000V or 1200V.

[0012] The capacitance value of the capacitor is 33-600PF; a signal transmission resistor is also connected in series on the water level detection branch to form a resistance-capacitance circuit, and the resistance value of the signal transmission resistor is determined by the internal resistance of the device that uses the water level detection branch to output the signal.

[0013] A device for measuring water comprises a water level probe, wherein the water level probe is connected in series with one end of a capacitor through a wire, and the other end of the capacitor is connected to a touch sensing signal input end of a computer measuring and controlling device with a touch sensing signal input interface end, thereby forming a basic water level detection branch. When there is no water or the water level is a certain distance away from the water level probe, the touch sensing signal input end cannot sense water and generates a low or high level signal corresponding to no water approaching or no water touching the water level probe; when there is water approaching the water level probe a certain distance but has not yet touched or touched the water level probe, the touch sensing signal input end senses the voltage generated by water approaching or water touching the water level probe and generates a high or low level signal corresponding to water approaching or water touching the water level probe; the water level probe is provided with one or more, corresponding to detecting water levels of different heights.

[0014] Further optimization measures include:

[0015] The certain distance is 0-1 mm; the water level probe is an elastic or rigid conductor.

[0016] The water level probe is provided with a waterproof layer or / and a sleeve outside, and the waterproof layer or / and a sleeve is a curved or flat object of a conductor, semiconductor or insulator, including a metal, plastic, ceramic or glass object.

[0017] Below the water level probe, a signal ground is provided at the place where the water rises to the water level probe, and the signal ground is connected to the signal ground of the computer measurement and control device.

[0018] The capacitor is composed of one or more capacitors. When more than two capacitors are included, they are connected in series or in series-parallel.

[0019] The total withstand voltage value of the capacitor is a safe withstand breakdown voltage value greater than or equal to 400V.

[0020] When the computer measurement and control device is powered by a 100-240V AC power supply, the withstand voltage of the capacitor is greater than or equal to 400V-1200V, especially 400V, 600V, 800V, 1000V or 1200V.

[0021] A signal transmission resistor is connected in series between the capacitor and the input terminal.

[0022] The capacitance value of the capacitor is 33-600PF.

[0023] The water level probes are provided with 1, 2, 3, 4 or more probes from low to high according to specific needs, and they and the corresponding capacitors constitute corresponding water level detection branches, and each water level detection branch is connected to the touch sensing signal input interface terminal corresponding to the computer measurement and control device.

[0024] The water level probes are provided with 1, 2, 3, 4 or more from low to high according to specific needs, and they and their corresponding capacitor series signal transmission resistor circuits constitute corresponding water level detection branches, and each water level detection branch is connected to the corresponding touch sensing signal input interface end of the computer measurement and control device.

[0025] The low or high level signal of the state of no water approaching or no water touching the water level probe is set to a state without key touch in the circuit; the high or low level signal of the state of water approaching or touching the water level probe is set to a state with key touch in the circuit.

[0026] An electrical appliance composed of any of the above-mentioned devices for measuring water, wherein the electrical appliance is any of a water level or water capacity sensor, a water level or water capacity measuring and controlling device, an automatic water replenishing water tower or water tank, an automatically controlled water adding electric water heater (boiler), a water dispenser, a beverage machine, a wine tank, a fermentation tank, an electric tea stove or an electric kettle.

[0027] The electrical appliance is an electric tea stove or electric kettle, including the computer measurement and control device, the water level detection branch and the electric hot water container. The electric hot water container is a metal water container, on which an electric heater is provided, and its inner bottom surface or side wall is grounded. Corresponding water level probes are provided at its lowest detection water level and / or highest detection water level, which are respectively used for water shortage / dry-burn prevention minimum water level measurement and control and / or boiling prevention maximum water level measurement and control; the capacitor of each water level detection branch is composed of one capacitor with a withstand voltage of more than 400V or two capacitors with a withstand voltage of more than 220V connected in series.

[0028] The electrical appliance is a beverage machine, including the computer measurement and control device, the water level detection branch and at least one beverage container. The inner bottom water-contacting part of each beverage container is grounded or grounded through a suspended grounding electrode, and the grounding electrode is connected to the signal ground. Corresponding water level probes are respectively provided at the lowest water limit level and the highest water limit level of the beverage container, which are respectively used for the lowest water level measurement and control and the highest water level measurement and control.

[0029] The electrical appliance is a water tank, a wine tank or a fermentation tank with a water level monitoring device.

[0030] The electrical appliance is a water level sensor or a water level measurement controller based on wireless signal communication of the Internet of Things.

[0031] Compared with the prior art, the beneficial effects of the utility model are as follows: since the water level probe is made of elastic or rigid metal conductor, the material selection is wide and the cost is extremely low. General steel wire, metal foil, steel plate, steel rod and spring can be used as water level probe. The water level probe is connected in series with one end of a capacitor C through a wire, and the other end of the capacitor is connected to a touch sensing signal input terminal I of a computer measurement and control device to form a water level detection branch. After numerous experiments, we found that the change of the induced voltage when the water level approaches or touches the water level probe and the change of the induced voltage when the water level is far away from the water level probe are obviously different. By using a computer (embedded computer, single-chip microcomputer) measurement and control device with a touch sensing signal input terminal, the induced voltage when the water level approaches or touches the water level probe is regarded as a human hand touching the key, and conversely, the induced voltage disappears when the water level is far away from the water level probe, as if the human hand leaves the key, so that the change value of the induced voltage can be captured timely and reliably, and is used to detect the water level after digital processing. Since no excitation DC power supply is applied to the input end of the touch sensing signal (passive detection), the liquid will not be ionized, the probe will not scale, and it will not consume power. The circuit is also less expensive than the general ultrasonic proximity switch probe. The non-contact water level sensor on the market generally costs tens to thousands of yuan, and can only measure the first-level water level. The utility model can use a single-chip computer to connect multiple water level detection branches at the same time to detect multiple levels of water level. Of course. In the case of a regular shape of the water container, the water capacity or water flow rate can also be measured. The utility model has a wide range of uses, especially for water level or water capacity sensors, water level or water capacity measurement and control devices, automatic water filling water towers or water tanks, automatic water adding electric heating (boiling) water dispensers, water dispensers, beverage machines, wine cans, and electric water boilers. When the capacitor uses a high-voltage capacitor with a high breakdown voltage, it can play a role in the safe isolation of strong and weak electricity, which is of great significance, especially for the small, closed, high-temperature, and high-humidity environment of the containers of kung fu tea stoves, electric water boilers, electric heating (boiling) water dispensers, water dispensers, and beverage machines. The utility model has low cost, safety, reliability, wide application environment, is not easy to scale and rust, and has great social and economic value no matter it is made into a sensor or an electrical appliance. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is the basic principle diagram of the water level detection circuit (water level detection branch, passive water level sensor, and signal-free transmission resistor) of the water level sensor or water level detection device of the utility model;

[0033] Figure 2 It is a schematic diagram of another implementation of the water level detection circuit (water level detection branch, passive water level sensor, and signal transmission resistor) of the water level sensor or water level detection device of the utility model;

[0034] Figure 3It is a schematic diagram of another embodiment of the water level detection circuit (passive water level sensor, with signal transmission resistor, and with single-chip computer) of the water level sensor or water level detection device of the utility model;

[0035] Figure 4 A schematic diagram of another embodiment of a water level detection circuit (a passive water level sensor with a signal transmission resistor, a single-chip computer and a radio frequency wireless transceiver system TX) of a water level sensor or a water level detection device of the utility model;

[0036] Figure 5 This is a principle diagram of the utility model for water level detection of a metal kettle (common to tea bar machines) or a water tank that can automatically add water to prevent dry burning and overflow (the water level probe goes deep into the kettle body and touches the water for detection);

[0037] Figure 6 This is a principle diagram of the utility model for water level detection of a glass pot (common to tea bar machines) or a plastic water tank (beverage machine, water tower) that can automatically add water to prevent dry burning and overflow (the water level probe elastically contacts the outer wall of the glass pot or plastic water tank to detect water without contact);

[0038] Figure 7 This is a schematic diagram of a water level detection circuit for an automatic water tower, water tank, water dispenser, beverage machine or wine tank, fermentation tank, canal, river or lake (multi-level water level, water capacity and flow rate can be measured). DETAILED DESCRIPTION

[0039] The following is combined with Figure 1-7 The embodiments further clearly and completely describe the technical principles of the utility model. Obviously, the described embodiments are only part of the implementation methods of the utility model, rather than all of the implementation methods. Any commercial use of measuring water level, capacity and flow based on the capacitive touch sensing principle falls within the scope of protection required by this patent.

[0040] It should be noted that when a component / part is referred to as being "set on" another component / part, it may be directly set on the other component / part or may be a component / part located therein. When a component / part is referred to as being "connected / coupled" to another component / part, it may be directly connected / coupled to the other component / part or there may be an intermediate component / part at the same time. The term "connection / coupling" used herein may include electrical and / or mechanical physical connections / couplings. The term "includes / comprising" used herein refers to the presence of a feature, step or component / part, but does not exclude the presence or addition of one or more other features, steps or components / parts. The term "and / or" used herein includes any and all combinations of one or more relevant listed items.

[0041] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0042] In addition, in the description of this application, if the terms "first" or "second" are used, they are only used for descriptive purposes and to distinguish similar objects. There is no order of precedence between the two, and they cannot be understood as indicating or implying relative importance. In addition, in the description of this application, unless otherwise specified, if the term "several" is used, it means 1 or more; "multiple" means two or more.

[0043] The utility model can be widely used in various occasions where water level detection is required, and can be used to make various devices with water level detection function based on this principle, but is not limited to the water level or water capacity sensors, water level or water capacity measurement and control devices, automatic water replenishment water towers or water tanks, automatic water-adding electric water heaters, water dispensers, beverage machines, wine tanks, fermentation tanks, and electric water boilers listed in the specification and embodiments.

[0044] Embodiment 1:

[0045] A water level sensor (see Figure 1 ), including a water level probe T made of elastic or rigid metal material as a signal sensing end, the water level probe is connected in series with a capacitor C through a wire to form a basic water level detection branch 1 ("basic" means: components can be added to this branch to further optimize the circuit performance), and its signal output terminal I outputs a detection signal to the outside for sampling by a computer with a touch detection signal input terminal (a chip that can be generally selected by single-chip embedded computers such as STC, Freescale, and BYD), and can also be used in combination with an ordinary hardware circuit through an external touch signal detection circuit, and then used in various process controls or household appliances.

[0046] Example 2 (see Figure 2 ) is to connect one or more signal transmission resistors R in series on the above detection branch to form a resistance-capacitance circuit to output the detection signal. The resistor R helps to improve the detection performance and adjust the detection sensitivity. The capacitor C and the resistor R are generally not assembled in front and back. It is best that the capacitor C is connected to the water level probe 1, and the output end of the resistor R is the signal output terminal I, which is matched with the touch signal input terminal of the computer measurement and control device (including the single-chip microcomputer MCU) when in use.

[0047] Example 3 (see Figure 3 ) is a computer measurement and control unit (MCU) in which a touch signal input terminal is directly connected to the signal output terminal I of Example 2, which is used as a multifunctional, intelligent water or water level sensor, and can also be directly equipped with peripheral circuits to form different electrical appliances.

[0048] Example 4 (see Figure 4 ) is based on Example 3, and an RF radio frequency wireless communication device is added to form a point-to-point, point-to-multipoint Internet of Things sensor or a remote intelligent water level (water) detection and control device. Alternatively, an embedded single-chip computer with an RF radio frequency wireless communication device embedded inside can be directly selected to form a small-volume computer measurement and control MCU.

[0049] Example 5 (see Figure 5 ) is based on Example 3, and a first-level water level detection is added to form a water level sensor or water measuring device with high water level and low water level detection, which can be widely used in water level detection control of automatic water-adding kung fu tea stoves, electric kettles, electric water heaters, water dispensers, beverage machines, water towers and water tanks. In kung fu tea stoves, electric kettles, electric water heaters, water dispensers, and beverage machines, the state of lack of water, water drying up, and full water can be reliably detected in a small electric heating container with high-temperature steam, and then the controller can be used to control water replenishment, quantitative water addition, stop heating to prevent dry burning, etc., and it can also be used as a basis for detecting the freshness of water.

[0050] In addition, in Example 5, capacitor C is formed by connecting two capacitors (capacitor C1 and capacitor C2) in series, and more capacitors can be used. One of the functions is to increase the strong electric security function, and the two-stage or multi-stage capacitors constitute a multi-channel anti-electric breakdown function. When the electrical appliance is a device that the human body needs to touch and control, the device must be approved by 3C and other safety regulations before it can be put on the market. When the capacitor of the utility model is selected with a breakdown voltage higher than the appropriate value of the voltage of the strong electric power source, it plays a role in preventing leakage and being shocked by strong electricity. For example, the electric heating tube of my country's electric teapot uses 220V alternating current. Selecting a capacitor with a breakdown voltage of more than 600V can prevent the strong electric hazards caused by the two-way breakdown of the electric heating tube or circuit board by 220V alternating current.

[0051] The total withstand voltage value of the capacitor can be greater than or equal to 400V, 600V, 800V, 1000V or 1200V. Some countries use AC 110V power supply, while others use 220V.

[0052] In this embodiment, the water level probe T1 and the water level probe T2 are both conductive probes made of stainless steel rods (tubes), which are liquid-tightly built and fixed at corresponding positions of the electric metal water container (stainless steel electric kettle body). The penetrating connection part between the water level probe T1 and the wall of the electric metal water container is liquid-tightly insulated.

[0053] Example 6 (see Figure 6) is also based on Example 3, with an additional level of water level detection, forming a water level sensor or a water measuring device with two levels of water level detection, high water level and low water level, which can be widely used in water level detection and control of automatic water-adding Kung Fu tea stoves, electric kettles, electric water heaters, water dispensers, beverage machines, water towers and water tanks.

[0054] Different from the sixth embodiment, the water containers of the kung fu tea stove, electric kettle, electric water heater, water dispenser, beverage machine, water tower and water tank are all insulators, for example, the kettle body of the electric kettle is made of glass.

[0055] The capacitor is an ordinary non-strong-electric high-voltage isolation capacitor. The water level probe T1 is against the outer wall of the water container, so the water level probe T1 can be made of an elastic body, such as a spring or a spring sheet, or a metal foil can be used to stick to the outer wall of the water container.

[0056] Example 7 (see Figure 7 ) is based on Example 3, and a multi-level (n water level probes T1-Tn) water level detection is set to form a water level sensor or water measuring device with two-level water level detection of high water level and low water level, which can be widely used in water level detection and control of automatic water-adding Kung Fu tea stoves, electric kettles, electric water heaters, water dispensers, beverage machines, water towers and water tanks.

[0057] The rigid water level probe can be made of stainless steel pipe or rod (wire), and when used, it is fixed at the height position of the water level to be detected in the metal water container 21 containing water (or aqueous solution) (see Figure 5 ), the wire is insulated and connected to the container in a liquid-tight manner, and the signal at the bottom of the container is grounded 3. Figure 5 When the water level probe T1 and the water level probe T2 are made of stainless steel pipes, the stainless steel pipes also constitute waterproof casings. The water level probes are insulated through the side wall of the container through the silicone seal ring 22, and the water level probes made of stainless steel pipes or rods (wires) are connected to the capacitor C with a wire to waterproof, and the capacitor C is then connected in series with the resistor R to output the detection signal. Figure 5 For example, a typical application is a stainless steel water container (electric teapot) 21 of a kung fu tea stove or a tea art stove, which includes two water level detection branches 1. The high water level probe T1 is used to detect the high water level (full water to prevent overflow), and the low water level probe T2 is used to measure the low water level (can be used to automatically control water replenishment or prevent dry boiling due to lack of water).

[0058] The elastic water level probe can be made of a spring (spring or spring sheet), which does not contact the water during use and touches the outer wall of the water barrier water container 23 (see Figure 6 ), the water container 23 is made of insulating glass, plastic or ceramic. For example, the water level probe T1 and the water level probe T2 are in contact with the outer wall of the water container (the bottom signal of the container is grounded) 2 made of glass or plastic to hold water (or aqueous solution) (see Figure 5 ), the outer wall of the container forms a water barrier to sense the water level. The principle is based on the voltage change induced by the change in air capacitance between the water in the container and the probe. The water level probe and capacitor C are connected by a wire. Figure 6 The most typical application is the glass water container (glass electric teapot) 23 of the Kung Fu tea stove or tea art stove, which includes two water level detection branches, the elastic water level probe T1 of the high water level is used to detect the high water level (full water to prevent overflow), and the elastic water level probe T2 of the low water level is used to detect the lowest water level (used to automatically control water replenishment or prevent dry boiling due to lack of water). It can also be a plastic waterproof sleeve that goes deep into the container to contact the water, and the water level probe is sealed in it.

[0059] Embodiment 8:

[0060] like Figure 7 As shown, a water level sensor based on wired or wireless signal transmission, the same as Example 7, also uses the change of capacitance to the ground when the water level approaches or touches the water level probe to measure the water level. A corresponding water level probe T is set at the water level to be measured. The water level probe T is connected in series with one end of a capacitor C through a wire, and the other end of the capacitor C is connected to a touch sensing signal input terminal I of a computer measurement and control unit (based on MCU), forming a water level detection branch. In this embodiment, the water level detection branch can be set as needed by one or more, such as 20 (omitted in the accompanying drawings), to measure the water level monitoring of up to 20 levels. As a part of the sensor, the computer measurement and control unit realizes wired or wireless signal transmission through a cable or RF radio frequency circuit (omitted in the figure).

[0061] As mentioned above, in the water level detection branch 3, connecting one or more signal transmission resistors R in series before or after the capacitor is beneficial for signal acquisition. The capacitor can also be made of more than two capacitors (such as Figure 7 As shown, capacitors C1, C2, C3, and C4 are connected in series or in series-parallel. The specific capacitance and resistance values ​​are easily obtained through calculation and experiment. Different single-chip computer chips have different input impedance values, which need to be adjusted appropriately.

[0062] Embodiments 1-8 can all constitute water level sensors. As long as the shape of the water container to be measured is fixed, they can be used as various water measuring devices. Through computer calculations, they can be used to measure water capacity and even water flow, and then used to make water level or water capacity and / or water flow measurement and control devices. In order to save space, they will not be elaborated here.

[0063] The physical principle underlying the water level measurement of the present invention is that the inventor's team discovered through numerous experiments that, in a water containing space, relative to the ground, water, the water level probe and the air layer therebetween form a variable capacitor. When water approaches the water level probe or touches the water level probe, the change in capacitance to the ground detected by the detection circuit is significantly different, and the change can be detected by a touch sensing chip. This physical phenomenon has great economic and social value in solving the problems existing in the prior art.

[0064] The method for measuring water level of the utility model is to measure the water level by utilizing the change of capacitance to ground when the water level approaches or touches the water level probe. A corresponding water level probe T is arranged at the water level to be measured. The water level probe is connected in series with one end of a capacitor C through a wire. The other end of the capacitor C is connected to a touch sensing signal input terminal I( Figure 6 In (I1, I2, I3...In) are connected to form a water level detection branch 1. When the water level is lower than the water level probe T by a certain distance (e.g., greater than 1 mm), the touch sensing signal input terminal I cannot sense the voltage change caused by water approaching or touching the water level probe, and a low-level signal Li (or a high-level signal Hi) corresponding to the state of no water approaching or touching the water level probe 1 is generated on the touch signal input terminal I; when water approaches or touches the water level probe, the touch sensing signal input terminal I senses that water approaches or touches the water level probe, and the touch sensing signal input terminal I senses that water approaches or touches the water level probe. The voltage change generated on the head generates a high-level signal Hi (or low-level signal Li) on the touch signal input terminal I corresponding to the state of water approaching or touching the water level probe 1. After receiving these two level signals, the computer control unit MCU performs corresponding processing according to different actual needs, and thus can make different products, such as water level or water capacity sensor, water level or water capacity measurement and control device, automatic water replenishment water tower or water tank, automatic control water adding electric water heater, water dispenser, beverage machine, wine tank, fermentation tank, electric water boiler.

[0065] To facilitate understanding and application, a specific application method is introduced below. The steps are as follows:

[0066] First, the low-level signal Li (which can also be conditioned to be a logic high level Hi) detected by the water level probe T when no water approaches or touches the water level probe is set in the computer initialization program to a state where no key is touched (i.e., when no water is detected rising to the water level probe); the high-level signal Hi (which can also be conditioned to be a logic low level Li) of the water level probe state when water approaches or touches is set in the computer initialization program to a state where a key is touched (i.e., when water is detected rising to the water level probe 1); then, the following timing control processing steps are set in the computer monitoring program: a. Start the virtual key scanning program; b. Detect the logic level signal state of the water level probe; state, thereby judging whether the button is touched or not: when the button is touched (high-level signal Hi is detected), it indicates that the water is detected to have risen to or exceeded the height of the water level probe, and the corresponding program control module is entered (for example: a signal to stop adding water is sent or a control to stop adding water is controlled); when the button is not touched (low-level signal Li is detected), it indicates that the water is detected to be lower than the preset distance to the water level probe, and the corresponding program control module is entered (for example: a signal to add water is sent or a control to add water is controlled, and for water shortage detection of the electric kettle, a signal that there is no water in the kettle and heating cannot be powered on is sent, or the heating power is directly controlled to be cut off); c. Return to step b for cyclic scanning processing.

[0067] The above method is only a principle introduction, and more application methods can be applied by analogy, which will not be described in detail here. All applications based on this principle should be limited to the scope of protection required by this patent application.

[0068] The utility model not only solves the problem of measuring water level, but also solves a problem that the prior art has not solved. This is a problem that the products such as tea bar machines and electric tea kettles (Kung Fu) on the market today generally have not solved: it must be able to safely isolate strong and weak electricity, not scale (less scale), and be able to automatically detect high and low water levels (full water) to implement control. Because the most commonly used and low-cost water level sensor is the electrode type water level sensor, the prior art is powered by direct current 12V or 24V, using the low resistance conductivity of water as a switch quantity to measure the water level. The DC power supply is made of an AC transformer and a rectifier, and the DC power supply will also supply the system control circuit (including the keyboard). When the 220V AC breaks down the AC transformer and the rectifier, the electrode type water level sensor will conduct dangerous high voltage to the tea bar machine and the electric tea kettle body, causing harm to the human body. On the other hand, the kettle body is usually heated by the AC 110V-240V electric heating tube at the bottom. When the insulation of the electric heating tube is damaged, the kettle body will inevitably carry a dangerous high voltage, which will be transmitted to the weak current circuit (board) through the electrode water level sensor and the wire, and then the weak current circuit (board) will be broken down, causing damage to human and machine safety; vice versa, when the circuit board transformer breaks down, the circuit board is damaged by strong electricity, and the high voltage and strong electricity are connected to the water through the circuit board, wires and electrode water level sensor, and then the entire kettle body is in a dangerous state. The original intention of the utility model is to solve this problem. Only by solving this problem, the use of the above-mentioned water level measurement solution of the utility model can fundamentally solve the problem of safe electricity use and low-cost water level measurement of tea bar machines, electric tea kettles (Kung Fu), electric water boilers, etc. To achieve safety standards, low-cost, micro-volume, and strong and weak electricity isolation should be implemented in both directions, and the following conditions should be met:

[0069] The total withstand voltage value of capacitor C is greater than or equal to the standard AC withstand voltage value specified by the corresponding national, international or industry safety regulations. Specifically, if the withstand voltage value of capacitor C is greater than or equal to 400V, such as 600V, 800V, 1000V, 1200V or 2000V, preferably a capacitor C with an AC withstand voltage of 700V-1200V. Capacitor C can be composed of multiple capacitors connected in series and in parallel (for example, 2 or 3 in series, or multiple in series and in parallel, see Appendix Figure 5 , Attachment Figure 7 ) to reduce volume, cost or enhance isolation withstand voltage strength. It is beneficial to connect a signal transmission resistor R in series between the capacitor C and the input terminal I, which can improve the stability and reliability of detection and facilitate sensitivity control. The capacitance value of the capacitor C can be set according to the reference circuit of the touch key input signal of the embedded computer of a specific manufacturer. For example, the withstand voltage of AC1000V, 33PF or 47PF, 100PF, 600PF can be selected, and the resistance can be preferably selected in 100Ω-10KΩ, such as 100Ω, 1KΩ, 5KΩ, 10KΩ. Which parameter is better can be determined by simple experimental testing.

Claims

1. A water level sensor, comprising a water level probe as a signal sensing end, characterized in that: The water level probe is made of elastic or rigid metal material, and is connected in series with a capacitor via a conductor to form a basic water level detection branch.

2. The water level sensor according to claim 1, characterized in that: The total withstand voltage of the capacitor is greater than or equal to 400V, 600V, 800V, 1000V or 1200V.

3. The water level sensor according to claim 1 or 2, characterized in that: The capacitance value of the capacitor is 33-600PF; a signal transmission resistor is also connected in series on the water level detection branch to form a resistance-capacitance circuit.

4. A device for measuring water, characterized in that: The invention comprises a water level probe (T), which is connected in series with one end of a capacitor (C) through a wire, and the other end of the capacitor is connected to a touch sensing signal input end (I) of a computer measuring and controlling device with a touch sensing signal input interface end, so as to form a basic water level detection branch. When there is no water or the water level is far away from the water level probe by a certain distance, the touch sensing signal input end cannot sense water and generates a low or high level signal corresponding to no water approaching or no water touching the water level probe; when there is water approaching the water level probe by a certain distance but has not yet touched or touched the water level probe, the touch sensing signal input end senses the voltage generated by water approaching or water touching the water level probe, and generates a high or low level signal corresponding to water approaching or water touching the water level probe on the touch signal input end; the water level probe (T) is provided with one or more, corresponding to detecting water levels (T1-Tn) of different heights.

5. The device for measuring water according to claim 4, characterized in that: The certain distance is 0-2 mm; the water level probe (T) is an elastic or rigid conductor.

6. The device for measuring water according to claim 5, characterized in that: The water level probe (T) is provided with a waterproof layer or / and a sleeve outside, and the waterproof layer or / and a sleeve is a curved or flat object of a conductor, semiconductor or insulator, including a metal, plastic, ceramic or glass object.

7. The device for measuring water according to claim 5, characterized in that: Below the water level probe (T), a signal ground (3) is provided at the point where the water rises to the water level probe, and the signal ground is connected to the signal ground of the computer measurement and control device.

8. The device for measuring water according to any one of claims 4 to 7, characterized in that: The capacitor (C) is composed of one or more capacitors. When more than two capacitors are included, they are connected in series or in series-parallel.

9. The device for measuring water according to claim 8, characterized in that: The total withstand voltage value of the capacitor is a safe withstand breakdown voltage value greater than or equal to 400V.

10. The device for measuring water according to claim 9, characterized in that: When the computer measurement and control device is powered by a 100-240V AC power supply, the withstand voltage of the capacitor is greater than or equal to 400V-1200V, including 400V, 600V, 800V, 1000V or 1200V.

11. The device for measuring water according to claim 8, characterized in that: A signal transmission resistor is connected in series between the capacitor and the input terminal.

12. The device for measuring water according to claim 8, characterized in that: The capacitance value of the capacitor is 33-600PF.

13. The device for measuring water according to claim 8, characterized in that: The water level probes are provided with 1, 2, 3, 4 or more probes from low to high according to specific needs, and they and the corresponding capacitors constitute corresponding water level detection branches, and each water level detection branch is connected to the touch sensing signal input interface terminal corresponding to the computer measurement and control device.

14. The device for measuring water according to claim 8, characterized in that: The water level probes are provided with 1, 2, 3, 4 or more from low to high according to specific needs, and they and their corresponding capacitor series signal transmission resistor circuits constitute corresponding water level detection branches, and each water level detection branch is connected to the corresponding touch sensing signal input interface end of the computer measurement and control device.

15. The device for measuring water according to claim 8, characterized in that: The low or high level signal of the state of no water approaching or no water touching the water level probe is set to a state without key touch in the circuit; the high or low level signal of the state of water approaching or touching the water level probe is set to a state with key touch in the circuit.

16. An electrical appliance comprising the device for measuring water according to any one of claims 4 to 15, characterized in that: The electrical appliance is any one of a water level or water capacity sensor, a water level or water capacity measuring and controlling device, an automatic water supply tower or water tank, an automatic water adding electric water heater, a water dispenser, a beverage machine, a wine tank, a fermentation tank, an electric tea stove or an electric kettle.

17. The electrical appliance according to claim 16, characterized in that: The electrical appliance is an electric tea stove or electric kettle, including the computer measurement and control device, the water level detection branch and the electric hot water container. The electric hot water container is a metal water container, on which an electric heater is provided, and its inner bottom surface or side wall is grounded. Corresponding water level probes are provided at its lowest detection water level and / or highest detection water level, which are respectively used for water shortage / dry-burn prevention minimum water level measurement and control and / or boiling prevention maximum water level measurement and control; the capacitor of each water level detection branch is composed of one capacitor with a withstand voltage of more than 400V or two capacitors with a withstand voltage of more than 220V connected in series.

18. The electrical appliance according to claim 16, characterized in that: The electrical appliance is a beverage machine, including the computer measurement and control device, the water level detection branch and at least one beverage container. The inner bottom water-contacting part of each beverage container is grounded or grounded through a suspended grounding electrode. Corresponding water level probes are respectively provided at the lowest water limit level and the highest water limit level of the beverage container, which are respectively used for the lowest water level measurement and control and the highest water level measurement and control.

19. The electrical appliance according to claim 16, characterized in that: The electrical appliance is a water tank, a wine tank or a fermentation tank with a water level monitoring device.

20. The electrical appliance according to claim 14, characterized in that: The electrical appliance is a water level sensor or a water level measurement controller based on wireless signal communication of the Internet of Things.

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