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

Abstract

A water level detection method, a water level sensor, a water measuring device and an electric appliance formed by the water measuring device are characterized in that the water level is detected according to the change of corresponding capacitance induction voltage when the water level is close to but does not touch or touches a water level probe and no water exists or the water is away from the water by a certain distance, and then corresponding processing is carried out according to the detection result. 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 invention relates to water detection technology, in particular to a water level sensor, a water measuring device and electrical appliances constructed therefrom. 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. Summary of the invention

[0005] A basic task of the present invention is to provide a new sensor for detecting water level (including water 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. It is particularly suitable for closed, humid, high-temperature, short-term high and low temperature changes, and narrow space occasions.

[0006] A further task of the present invention 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 present invention is to provide several electrical appliances with water level measurement function based on the sensor principle of the present invention.

[0008] The task of the present invention is achieved through the following technical solutions:

[0009] A water level sensor comprises a water level probe made of elastic or rigid metal as a signal sensing end. The water level probe 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 resistor on the resistance-capacitance circuit 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, 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 the state of no water approaching or no water touching the water level probe on the touch signal input end; 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 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 greater than or equal to the safe breakdown voltage value defined by national, international or industry safety standards.

[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 water level probes from low to high according to specific needs, which are connected in series with the corresponding capacitors and signal transmission resistors to form 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.

[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. The corresponding water level probe is provided at the lowest detection water level and / or the highest detection water level, which is used for water shortage / anti-dry-burning lowest water level measurement and control and / or anti-boiling highest water level measurement and control respectively; 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 communication of the Internet of Things.

[0031] The water level detection method of the above water level sensor, the device for measuring water, and the electrical appliance constituted thereby is characterized in that: at the height position of the container grounded at the bottom that needs to measure the water level, flow rate or water capacity, the corresponding water level probe is arranged. The water level probe is connected in series with a capacitor through a wire to form a water level detection branch, or the water level probe is connected in series with a capacitor and a resistor through a wire to form a water level detection branch. According to the change in the induced capacitance caused by the change in the distance between the water level and the water level probe, the voltage change value at the computer port with a touch induction detection signal input end is used to detect the water level of the corresponding probe.

[0032] The water level detection method described above includes the following detection steps: First, set the low-level signal Li or high-level signal Hi detected by the water level probe when there is no water near or touching the water level probe to the state of no button touch in the computer initialization program; set the high-level signal Hi or low-level signal Li detected by the water level probe when there is water near or touching the water level probe to the state of having a button touch in the computer initialization program, that is, set the state when the water is detected to rise to the water level probe to having a button touch; set a monitoring program to make the computer execute the following steps: a. Start the virtual button scanning program; b. Detect whether there is a button touch? If there is, that is, detect the high-level signal Hi or low-level signal Li, indicating that the water is detected to rise to or exceed the height of the water level probe, and transfer to the corresponding program control module; if not, that is, detect the low-level signal Li or high-level signal Hi, indicating that the water is detected to be lower than the preset distance to the water level probe, and transfer to the corresponding program control module; c. Return to step b for cyclic scanning and processing.

[0033] Compared with the prior art, the beneficial effects of the present invention 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 changes of the induced voltage when the water level approaches or touches the water level probe and 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 (or conductive solution such as water) 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 negligible compared to 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 present invention 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 present invention 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 replenishment water towers or water tanks, automatic water-adding electric heating (boiling) water dispensers, water dispensers, beverage machines, wine cans, and electric tea stoves. When the capacitor is selected from 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 in the small, closed, high-temperature, and high-humidity environment of the containers of kung fu tea stoves, electric tea stoves, electric heating (boiling) water dispensers, water dispensers, and beverage machines. This may be the reason why all Kung Fu tea stoves, electric tea stoves and tea bar machines with anti-dry burning and / or overflow high water level detection probes in the market today cannot pass the 3C national mandatory safety quality certification. Whether the present invention is made into a sensor or an electrical appliance, it has low cost, is safe and reliable, has a wide range of applicable environments, is not easy to scale or rust, and has great social and economic value. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a basic principle diagram of a water level detection circuit (water level detection branch, passive water level sensor, and signal-free transmission resistor) of a water level sensor or a water level detection device of the present invention;

[0035] Figure 2It is a schematic diagram of another embodiment of a water level detection circuit (water level detection branch, passive water level sensor, and signal transmission resistor) of a water level sensor or water level detection device of the present invention;

[0036] Figure 3 A schematic diagram of another embodiment of a water level sensor or a water level detection circuit of a water level detection device (a passive water level sensor with a signal transmission resistor and a single-chip computer) of the present invention;

[0037] Figure 4 A schematic diagram of another embodiment of a water level sensor or a water level detection circuit of a water level detection device (a passive water level sensor with a signal transmission resistor, a single-chip computer and a radio frequency wireless transceiver system TX) of the present invention;

[0038] Figure 5 The schematic diagram of the present invention 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);

[0039] Figure 6 The schematic diagram of the present invention for water level detection of a glass kettle (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 kettle or plastic water tank to detect water without contact);

[0040] Figure 7 The present invention is a schematic diagram of a water level detection circuit for automatic water supply towers, water tanks, water dispensers, beverage machines or wine tanks, fermentation tanks, canals, rivers and lakes (multi-level water levels, water capacity and flow rate can be measured). DETAILED DESCRIPTION

[0041] The following is combined with Figure 1-7 The embodiments further clearly and completely describe the technical principles of the present invention. Obviously, the described embodiments are only part of the implementation methods of the present invention, 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.

[0042] It should be noted that when a component / part is referred to as being "disposed on" another component / part, it can be directly disposed on the other component / part or there can also be intermediate components / parts therebetween. When a component / part is referred to as being "connected / coupled" to another component / part, it can be directly connected / coupled to the other component / part or there may be intermediate components / parts present at the same time. The term "connected / coupled" used herein can include electrical and / or mechanical physical connections / couplings. The term "comprising / including" used herein means the presence of features, steps or components / parts, 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 of the related listed items.

[0043] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field to which this application belongs. The terms used herein are for the purpose of describing particular embodiments only and are not intended to limit this application.

[0044] In addition, in the description of this application, if terms such as "first", "second" are used, they are only for descriptive purposes and to distinguish similar objects, and there is no sequence between them, nor can they be understood as indicating or implying relative importance. Furthermore, in the description of this application, unless otherwise stated, if the term "several" is used, its meaning refers to one or more than one; the meaning of "multiple" is two or more than two.

[0045] The present invention can be widely used in various occasions where water level needs to be detected, and various devices with water level detection functions can be made based on this principle, and are not limited to the water level or water capacity sensors, water level or water capacity measurement and control devices, automatic water replenishing water towers or water tanks, automatic control electric heating (on) water heaters, water dispensers, beverage machines, wine tanks, fermentation tanks, and electric tea stoves listed in the specification and embodiments.

[0046] Embodiment 1:

[0047] 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 that components can be added to this branch to further optimize the circuit performance). Its signal output end I outputs a detection signal for sampling by a computer (chips such as Holtek, Freescale, STC, BYD single-chip embedded computers are generally selectable) with a touch detection signal input end, or can be used in combination with an external touch signal detection circuit and an ordinary hardware circuit, and then used for various process controls or household appliances.

[0048] 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.

[0049] 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.

[0050] 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.

[0051] 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 (including tea bar machines equipped with electric kettles), beverage machines, water towers and water tanks. In kung fu tea stoves (electric tea kettles equipped with electric kettles), 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, heating stop to prevent dry burning, etc., and it can also be used as a basis for detecting the freshness of water.

[0052] 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 present invention 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.

[0053] The total withstand voltage value of the capacitor can be selected to be greater than or equal to 400V, 600V, 800V, 1000V or 1200V. In some countries, the industrial frequency power supply is 110V AC, and in some it is 220V.

[0054] In this embodiment, both the water level probe T1 and the water level probe T1 are conductor probes made of stainless steel rods (tubes), and are liquid-tightly built-in and fixed at corresponding positions on the electrothermal metal water container (the stainless steel electric kettle body). The crossing connection part between the water level probe T1 and the wall of the electrothermal metal water container is liquid-tightly insulated and connected.

[0055] Embodiment 6 (see Figure 6 ) is also based on Embodiment 3, with an additional level of water level detection added, constituting a water level sensor or device for measuring water with two levels of high water level and low water level detection, and can be widely used for 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.

[0056] The water containers of some kung fu tea stoves, electric kettles, electric water heaters, water dispensers, beverage machines, water towers and water tanks are made of insulating materials. For example, the kettle body of an electric kettle is made of glass.

[0057] In this case, a single ordinary non-high-voltage isolation capacitor for strong electricity can be used for the capacitor. Since the water level probe T1 abuts against the outer wall of the water container, the water level probe T1 can be made of an elastomer, such as a spring or a spring sheet, or a metal foil can be pasted on the outer wall of the water container.

[0058] Embodiment 7 (see Figure 7 ) is based on Embodiment 3, with multi-level (n water level probes T1 - Tn) water level detection set up, constituting a water level sensor or device for measuring water with two levels of high water level and low water level detection, and can be widely used for 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.

[0059] The rigid water level probe can be made of stainless steel tubes or rods (wires), and is fixed at the height position of the water level to be detected in the metal water container 21 containing water (or aqueous solution) during use (see Figure 5 ), the wire is insulated from the container and is liquid-tightly connected, and the signal at the bottom of the container is grounded 3. Figure 5 In, when the water level probes T1 and T2 are made of stainless steel tubes, the stainless steel tubes simultaneously form water isolation sleeves. The water level probe passes through the side wall of the container insulated by a silica gel sealing ring 22, and the water level probe made of stainless steel tubes or rods (wires) and the capacitor C are connected in a water-isolated manner by wires, and the capacitor C is then connected in series with the resistor R and outputs a detection signal outward. Figure 5For 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).

[0060] 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 water level 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.

[0061] Embodiment 8:

[0062] 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).

[0063] 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 7As shown, it is composed of capacitors C1, C2, C3, and C4 connected in series or in series-parallel. The specific capacitance values and resistances can be easily obtained through calculation and experimentation. Different single-chip computer chips have different input impedance values and need to be adjusted appropriately.

[0064] Examples 1-8 can all form a water level sensor. As long as the shape of the water container to be measured is fixed, it can be used as various devices for measuring water. Through the operation of a computer, it can be used to measure the water volume and even the water flow rate. Furthermore, it can be used to manufacture a water level or water volume and / or water flow rate measuring and controlling device. For the sake of saving space, it will not be elaborated here.

[0065] The physical principle on which the present invention measures the water level was discovered by the inventor's team through countless experiments. In a water-containing space, relative to the ground, the water, the water level probe, and the air layer therebetween form a variable capacitor. When the water approaches or touches the water level probe, there are obvious differences in the change amount of the capacitance to the ground detected in the detection circuit. The touch sensing chip can detect this change. This physical phenomenon has great economic and social value for solving the problems existing in the prior art.

[0066] The method for measuring the water level in the present invention is to measure the water level by using the change in the capacitance to the ground when the water level approaches or touches the water level probe. At the position of the water level to be measured, a corresponding water level probe T is set. The water level probe is connected in series with one end of the capacitor C through a wire, and the other end of the capacitor C is connected to the touch sensing signal input terminal I ( Figure 6 in I1, I2, I3... In) of the computer measurement and control unit MCU 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 generated by the water approaching or touching the water level probe, and a low-level signal Li (or high-level signal Hi) corresponding to the state of no water approaching or touching the water level probe 1 is generated at the touch signal input terminal I; when there is water approaching or touching the water level probe, the touch sensing signal input terminal I can sense the voltage change generated by the water approaching or touching the water level probe, and a high-level signal Hi (or low-level signal Li) corresponding to the state of water approaching or touching the water level probe 1 is generated at the touch signal input terminal I. After receiving these two level signals, the computer measurement and control unit MCU makes corresponding processing according to different actual needs, and then different products can be made, such as any one of a water level or water volume sensor, a water level or water volume measuring and controlling device, an automatic water replenishing water tower or water tank, an automatic control electric heating (on) water dispenser, a water dispenser, a beverage machine, a wine tank, a fermentation tank, and an electric tea stove.

[0067] For the convenience of understanding and application, a specific application method is introduced below, and the steps are as follows:

[0068] First, set the low-level signal Li detected by the water level probe T when the anhydrous approaches or touches the water level probe (which can also be conditioned to a logic high level Hi) to the state of no button touch (i.e., when it is detected that the water does not rise to the water level probe) in the computer initialization program; set the high-level signal Hi of the water level probe state when water approaches or touches (which can also be conditioned to a logic low level Li) to the state of button touch (i.e., when it is detected that the water rises to the water level probe 1) in the computer initialization program. Then, set the following timing control processing steps in the computer monitoring program: a. Start the virtual button scanning program; b. Detect whether there is button touch? If yes (detecting the high-level signal Hi), it means that it is detected that the water has risen to or exceeded the height of this water level probe, and transfer to the corresponding program control module (for example: send a signal to stop adding water or control to stop adding water); if no (detecting the low-level signal Li), it means that it is detected that the water is lower than the preset distance to this water level probe, and transfer to the corresponding program control module (for example: send a signal to allow adding water or control to add water, for the water shortage detection of an electric kettle, send a signal that there is no water in the kettle and it cannot be powered on for heating, or directly control to cut off the heating power); c. Return to step b for cyclic scanning processing.

[0069] The above method is only a principle introduction, and more application methods can be deduced by analogy, so it will not be elaborated here. All applications based on this principle should be limited within the scope claimed in this patent application.

[0070] While solving the problem of measuring water level, the present invention also solves a difficult problem that has not been solved by the prior art, which is a problem generally not solved by products such as tea bar machines and electric teapots (kung fu) on the current market: it is necessary to 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) for implementation control. Because the most commonly used and low-cost water level sensor is the electrode type water level sensor, and the prior art all supplies power through DC 12V or 24V, and uses the low-resistance conductivity of water to measure the water level as a digital quantity. The DC power supply is made of an AC transformer and a rectifier, and the DC power supply also supplies the system control circuit (including the keyboard) at the same time. When the 220V AC breaks down the AC transformer and the rectifier, the electrode type water level sensor will conduct the dangerous high voltage to the kettle body of the tea bar machine or the electric teapot, causing harm to the human body. On the contrary, the kettle body is generally heated by an 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 dangerous high voltage, and it will conduct the dangerous high voltage to the weak current circuit (board) through the electrode type water level sensor and the wire, and then break down the weak current circuit (board), causing damage to human-machine safety; vice versa, when the circuit board transformer breaks down and the circuit board is damaged by strong electricity, the high voltage and strong electricity will be connected to the water through the circuit board, the wire and the electrode type water level sensor, and then the entire kettle body is in a dangerous state. This is why the existing automatic water filling electric kettles with high water level (full water) control cannot pass safety certifications such as 3C and CQC. The original intention of the present invention is to solve this problem. Only by solving this problem can the above-mentioned water level measurement scheme of the present invention fundamentally solve the problems of safe electricity use and low-cost water level measurement of tea bar machines, electric teapots (kung fu), electric water heaters, etc. Otherwise, the products made cannot be sold. According to the investigation, none of the similar products on the current market can meet the safety standards. This is the original intention of the present invention. To achieve safety compliance and implement low cost, small volume, and strong-weak electricity isolation in both directions, the following conditions should be met:

[0071] The total withstand voltage value of the capacitor C is greater than or equal to the standard AC withstand voltage value specified by the corresponding national, international or industrial electrical safety regulations. Specifically, for example, if the withstand voltage value of the capacitor C is selected to be greater than or equal to 400V, such as 600V, 800V, 1000V, 1200V or 2000V, a capacitor C with an AC withstand voltage of 700V - 1200V is preferably used. The capacitor C can be composed of multiple capacitors connected in series and parallel (for example, 2 or 3 in series, or multiple in series and parallel, see attached Figure 5 Attach 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 AC400, 600-800V, 1000V, 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 made of elastic or rigid metal material as a signal sensing end, wherein the water level probe is connected in series with a capacitor through a wire to form a basic water level detection branch.

2. The water level sensor according to claim 1, wherein: 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 measurement and control unit (MCU) 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 a low or high level signal corresponding to no water approaching or no water touching the water level probe is generated on the touch signal input end; 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 a high or low level signal corresponding to the state of water approaching or water touching the water level probe is generated 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 4-7, 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, wherein: The total withstand voltage value of the capacitor is greater than or equal to the safe breakdown voltage value defined by national, international or industry electrical safety standards.

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

13. The water measuring device according to claim 8, wherein: 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 water measuring device according to claim 8, characterized in that: The water level probes are provided with 1, 2, 3, 4 or more water level probes from low to high according to specific needs, which are connected in series with the corresponding capacitors and signal transmission resistors to form 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.

15. The device for measuring water according to claim 8, characterized in that: The low or high level signal indicating the state of no water approaching or touching the water level probe is set to the state of no key touch in the circuit; the high or low level signal indicating the state of water approaching or touching the water level probe is set to the state of key touch in the circuit.

16. An electrical appliance constituted by the water measuring device according to any one of claims 4-15, 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 replenishing water tower or water tank, an automatic control electric heating (boiling) water dispenser, 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 an electric kettle, including the computer measuring and controlling device, the water level detection branch and an electric hot water container. The electric hot water container is a metal water container, on which there is an electric heater, and its inner bottom surface or side wall is grounded. At its lowest detection water level and / or highest detection water level, there are corresponding water level probes respectively used for measuring and controlling the lowest water level for water shortage / preventing dry burning and / or the highest water level for preventing boiling over; the capacitors of each water level detection branch are composed of 1 capacitor with a withstand voltage of more than 400V or 2 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 measuring and controlling device, the water level detection branch and at least one beverage container. The water-touching part at the inner bottom of each beverage container is grounded or grounded through a suspended grounding electrode. At the lowest limit water level and the highest limit water level of the beverage container, there are corresponding water level probes respectively used for measuring and controlling the lowest water level and the highest water level.

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 measuring and controlling device based on wireless communication.

21. The water level detection method of the water level sensor, the device for measuring water, and the electrical appliance constituted thereby according to any one of claims 1-20, characterized in that: At the height position where the water level, flow or water capacity needs to be measured in the container grounded at the bottom, the corresponding water level probe is set. The water level probe is connected in series with a capacitor through a wire to form a water level detection branch, or the water level probe is connected in series with a capacitor and a resistor through a wire to form a water level detection branch. According to the change in the induced capacitance caused by the change in the distance between the water level and the water level probe, the voltage change value at the computer port with a touch induction detection signal input end is used to detect the water level of the corresponding probe.

22. The water level detection method according to claim 21, wherein: It includes the following detection steps: First, set the low level signal Li or high level signal Hi detected by the water level probe when no water approaches or touches the water level probe to the state of no key touch in the computer initialization program; set the high level signal Hi or low level signal Li detected by the water level probe when water approaches or touches the water level probe to the state of key touch in the computer initialization program, that is, set the state when it is detected that the water rises to the water level probe to the state of key touch; set a monitoring program to make the computer execute the instructions containing the following steps in real time: a. Start the virtual key scanning program; b. Detect whether there is a key touch? If yes, that is, detect the high level signal Hi or low level signal Li, indicating that it is detected that the water rises to or exceeds the height of the water level probe, and transfer to the corresponding program control module; if no, that is, detect the low level signal Li or high level signal Hi, indicating that it is detected that the water is lower than the preset distance to the water level probe, and transfer to the corresponding program control module; c. Return to step b for cyclic scanning and processing.

Images