Device for measuring and controlling water level

Abstract

The utility model discloses a device for measuring and controlling a water level, which is characterized in that a preset detection signal is output to a metal probe by a resistance-capacitance series branch formed by connecting a capacitor and a resistor in series through a program-controlled strong push-pull output mode output interface of a computer; and the program-controlled pull-up input mode input interface detects an input signal fed back by the probe through a resistor-capacitor series branch formed by connecting a capacitor and a resistor in series so as to measure and control the water level. The device can be manufactured into various devices for measuring and controlling the water level, such as a water level or water capacity sensor, an intelligent electric kettle, a water dispenser, a water tank and the like, and particularly has the advantages of safety, reliability, scaling prevention, electric shock prevention, small size, low cost and long service life when being used in high-humidity, high-temperature and closed containers.

Description

Technical Field

[0001] The utility model relates to water detection technology, in particular to a device for measuring and controlling water level. Background Art

[0002] The water level detection sensors frequently used in daily life are non-contact ultrasonic liquid level sensors, Hall element electromagnetic induction liquid level sensors, reed switch float sensors, and electrode water level sensors that utilize the conductive (resistance) structure of ordinary water. These water level sensors are widely used in boilers, water towers, wine tanks and other devices that need to measure and control water levels or water volumes.

[0003] There are many problems with the devices for measuring water in the prior art, such as: 1. The problems with non-contact ultrasonic liquid level sensors, Hall element electromagnetic induction liquid level sensors, and reed switch float sensors are high cost, large size, and are greatly restricted by the application environment. They also require customization, and the customization time is long. Especially in some closed applications, small spaces, high temperatures, and high humidity occasions, there is no way to use them at all. For example, they are not applicable to devices such as electric kettles, tea bar machines, and water dispensers that require automatic control to prevent dry burning, automatic water addition, and water boiling. This is a major problem that plagues the industry.

[0004] The prior art electric kettles for measuring and controlling water levels include common electrode-type water level probes made of metal rods, which are not only easy to scale and difficult to clean, but also cannot be installed in the small inner cavity of the electric kettle. High-temperature and high-humidity water vapor affects the reliability of detection, and scale can also cause detection failure. In particular, the prior art common electrode-type water level probes made of metal rods have many insurmountable defects because their measurement and control circuits use the conductivity of the electrode, the 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 under the condition of low cost, few signal connection lines and detection of multiple water levels, resulting in unreliable measurement; 2. Applying a DC voltage to the electrode will form an electric field between it and the ground 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 attach to the electrodes, but the conductivity of the scale is unstable, which often leads to system failure and inability to measure the water level, which in turn causes the entire application system to fail to detect, resulting in serious accidents and the return of sold products.

[0005] 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. It is understood that the tea stoves with electrode-type high and low water level control on the market are not reliable, and even if there are, they are not in compliance with safety regulations and often fail to detect. Utility Model Content

[0006] A basic task of the utility model is to provide a new device for measuring and controlling water level. The product manufactured by the device 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-time high and low temperature changes and narrow space occasions.

[0007] A further task of the utility model is to provide a device for measuring and controlling water level with low cost, simple circuit and strong / weak current safety isolation and an electrical appliance constructed by using the device.

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

[0009] The utility model, under a basic technical solution, includes two alternative and replaceable technical solutions, both of which can achieve the purpose of the invention:

[0010] Solution 1:

[0011] A device for measuring and controlling water level, the specific scheme is:

[0012] A device for measuring and controlling water level (a device for spontaneous / self-detecting and controlling water level), comprising a computer, on which at least one program-controlled input / output conversion interface is provided, which is connected to a corresponding resistor-capacitor series branch composed of a corresponding number of capacitors and resistors in series, and then connected to a corresponding metal probe through a wire; the ground signal line of the computer is connected to the bottom ground terminal of the water containing space to be measured; the program-controlled input / output conversion interface is a conversion interface with program-controlled switching of a strong push-pull output mode and a pull-up input mode, forming a device with one or more levels of water level measurement and control.

[0013] The computer is a single-chip computer, which has the following timing signal measurement and control modules built into it: (1) Spontaneous detection signal: first set the programmable input / output conversion interface to a strong push-pull output mode, and then the computer controls it to send a pulse detection output signal; (2) Self-received detection signal: set the programmable input / output conversion interface to a pull-up input mode, and detect the input signal corresponding to the output signal feedback in real time, and compare it according to the set logic. When the input signal is at a high level, it indicates that there is no water at the water level. When the input signal state is at a low level, it indicates that there is water at the water level.

[0014] The timing signal (1) is: firstly, the program-controlled input / output conversion interface is set to the strong push-pull output mode, and a certain time t0 is set to make the strong push-pull output state stable; then, the computer is programmed to send a high-level detection output signal, and a certain time t1 is set to make the output signal stable; then, the computer is programmed to send a low-level detection output signal, and a certain time t2 is set to make the output signal stable; the timing signal (2) is: the program-controlled input / output conversion interface is set to the pull-up input mode, and a certain time t3 is delayed to make the input signal corresponding to the output signal feedback stable, and then the input signal is detected in real time. When the input signal is at a high level, it indicates that there is no water at the water level, and when the input signal is at a low level, it indicates that there is water at the water level.

[0015] The interval times t0, t1, t2 and t3 are 0-100 ms.

[0016] The interval time t0 is 60-100 ms, and t1, t2 and t3 are 3-30 ms.

[0017] The device for measuring and controlling the water level is any one of a water level sensor, an electric kettle, a tea bar machine, a water dispenser, a boiler, a water tower or a water storage tank.

[0018] The capacitor is a high-voltage isolation capacitor, and its withstand voltage is greater than or equal to AC220V.

[0019] The capacitor is a high voltage isolation capacitor with a withstand voltage value within the range of AC220V-2000V.

[0020] The capacitor is a high-voltage isolation capacitor with a withstand voltage of AC220V, 400V, 600V, 800V, 1000V, 1200V or 2000V, and the capacitance value of the capacitor is 33-600PF.

[0021] Option 2:

[0022] Another device for measuring and controlling water level, the specific scheme is:

[0023] The device for measuring and controlling water level (which is a device for independently measuring and controlling water level) includes an embedded computer, on which one or more output interfaces in a strong push-pull output mode and one or more corresponding input interfaces in a pull-up input mode are provided. The output interface sends out a detection signal, and the input interface detects the detection signal fed back by the output interface. Corresponding to the number of input interfaces, a corresponding number of metal probes are provided, and the probes are placed in water containing spaces at various water levels to be measured, and the bottom of the water containing space is connected to a ground signal line. Each probe is connected in parallel to two resistor-capacitor series branches formed by a capacitor and a resistor in series through a wire, and then the two resistor-capacitor series branches are respectively connected to the output interface and the input interface.

[0024] Further optimization measures are: the device for measuring and controlling the water level includes the following measurement and control logic signals, the output interface sends out a pulse detection output signal, the input interface detects the input signal corresponding to the output signal feedback in real time, when the input signal is at a high level, it indicates that there is water at the water level, and when the input signal state is at a low level, it corresponds to that there is no water at the water level.

[0025] There are a plurality of output interfaces in the strong push-pull output mode, and each of the input interfaces in the pull-up input mode corresponds to one output interface in the strong push-pull output mode.

[0026] There are multiple pull-up input mode input interfaces, and there are correspondingly multiple RC series branches connected to them; there is only one strong push-pull output mode output interface corresponding to the pull-up input mode input interface, forming a common output interface, which is connected to the corresponding probe through the corresponding RC series branch.

[0027] The output interface first sends out a measurement and control signal in the following measurement and control sequence: the output interface first sends out a high-level detection output signal, then delays a signal stabilization time Tw1, and then the output interface sends out a low-level detection output signal, and then delays another signal stabilization time Tw2 to form a pulse signal; when the input signal is detected as a high level, it indicates that there is water at the water level, and when the input signal state is detected as a low level, it indicates that there is no water at the water level.

[0028] The capacitance value of the capacitor is 33-600PF, and the capacitor is a high-voltage isolation capacitor with a withstand voltage greater than or equal to AC240V.

[0029] The device for measuring and controlling the water level can be any one of a water level sensor, an electric kettle, a tea bar machine, a water dispenser, a boiler, a water tower or a water storage tank. This example is not exhaustive, and all non-creative ones can be avoided and fall within the scope of protection required by this patent.

[0030] Beneficial Effects

[0031] Compared with the prior art, the utility model has the following beneficial effects: due to the adoption of the above technical solution, the capacitor's direct current isolation and alternating current blocking effect makes the probe have no direct current voltage, does not generate a direct current electric field, and thus does not ionize the liquid, so it is not easy to scale, does not consume power, and the circuit cost is reduced to negligible compared with the probe of the prior art. The utility model can use an embedded or single-chip computer to connect multiple water level detection branches at the same time to detect multi-level water levels. Of course, in the case of a regular shape of a water container, water capacity or water flow can also be measured. The utility model has a very 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, electric kettles. 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 for the small, closed, high-temperature, and high-humidity environment of the containers of kung fu tea stoves, electric kettles, electric heating (boiling) water dispensers, water dispensers, and beverage machines. The utility model can greatly reduce the cost of the electrical appliance for measuring and controlling water, whether it is made into civil or industrial use, and has the advantages of preventing electric shock, being safe and reliable, being applicable to a wide range of environments, and the probe is not easy to scale or rust. In particular, it can be used in high-humidity, high-temperature (boiling water) and closed containers, and has good social and economic value. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a basic circuit diagram of a water level measuring and controlling device of the utility model - used to detect the first-level water level [or the water level at a certain point]: such as full water, maximum water level, etc.;

[0033] Figure 2 This is a circuit schematic diagram of another device for measuring and controlling water level of the utility model. Taking the intelligent fully automatic tea art stove as an example, it can measure the two-level water level of the electric kettle [water levels at two different heights]: high water level [highest limit water level, i.e. full water] and low water level [lowest water level, water shortage, anti-dry burning limit water level]);

[0034] Figure 3 This is a circuit schematic diagram of another device for measuring and controlling water level in the utility model - used for high, medium and low water level detection;

[0035] Figure 4 This is a control timing flow chart of the device for detecting and controlling water level of the utility model;

[0036] Figure 5 This is a circuit schematic diagram of another water level measuring and controlling device of the utility model - used to detect the first-level water level [or the water level at a certain point]: such as full water, maximum water level, etc.;

[0037] Figure 6 This is a circuit schematic diagram of another device for measuring and controlling water level of the utility model, which is used for high, medium and low water level detection;

[0038] Figure 7 The present invention is a control timing flow chart of another device for measuring and controlling water level. 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, not all of the implementation methods. Any commercial use of the principle of the utility model to measure water level, capacity and flow 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 on the basis of this principle to produce various devices with single-stage, multi-stage or multi-point water level detection functions, and 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 kettles listed in the specification and embodiments.

[0044] Embodiment 1:

[0045] A device for measuring and controlling water level. This is a device for spontaneous / self-detecting and controlling water level. Figure 1 and Figure 4 .

[0046] The method for measuring and controlling the water level of the device is: using a programmable input / output conversion interface of a computer, after outputting a predetermined detection signal to a metal probe through the programmable conversion interface, the conversion interface is then programmable to self-check the input signal fed back by the probe to thereby measure and control the water level, the method comprises the following steps: (1) preparation: placing the probe in a water containing space to be measured, connecting the bottom of the water containing space to a grounding signal line, and connecting the probe to the programmable input / output conversion interface through a wire via a capacitor and a resistor in series to form a resistor-capacitor series branch; (2) spontaneous detection signal: first setting the programmable input / output conversion interface to a strong push-pull output mode, and then computer programmable to send a pulse detection output signal; (3) self-receiving detection signal: setting the programmable input / output conversion interface to a pull-up input mode, real-time detecting the input signal corresponding to the output signal feedback, and comparing according to the set logic, when the input signal is detected to be at a high level, it indicates that there is no water at the water level, and when the input signal is detected to be at a low level, it indicates that there is water at the water level, which is determined by the state of the probe when there is water and when there is no water and the logic design of the transmission circuit. For example, for this embodiment, the relationship of the logic setting is that when there is water, when the computer program-controlled strong push-pull output sends a pulse detection output signal, if there is water, the probe is grounded through the water, and the water is a capacitor and is charging. When the computer program-controlled pull-up input mode is in effect, the water capacitor is discharged. Under the action of the designed resistance-capacitance branch, when the input signal is detected as a low level, it indicates that there is water (the water level has reached this level); on the contrary, when there is no water, the probe is suspended, and the water capacitor cannot be charged. Under the action of the designed resistance-capacitance branch, when the input signal is detected as a high level, it indicates that there is no water (the water level has not reached this level). Since the specific signal transmission logic circuit is well known to those skilled in the art, and the specific pulse time parameters vary due to the different internal resistances of the input / output interfaces of different single-chip microcomputers, this can be determined through a limited number of experiments, and this article will not repeat them (the same below).

[0047] The device for self-generated / self-detection and control of water level in this embodiment comprises the water containing space 1, and a metal probe T1 for measuring the high water level (for measuring and controlling the maximum amount of water added) is arranged above the water containing space 1. The circuit of the device for self-generated / self-detection and control of water level comprises an embedded or single-chip computer MCU (single-chip microcomputer), and a program-controlled input / output conversion interface I / O1 is arranged on the computer. The program-controlled input / output conversion interface I / O1 is connected to one end of a series resistor-capacitor branch circuit composed of a capacitor C1 and a resistor R1 connected in series, and the other end of the series resistor-capacitor branch circuit is connected to a probe T1 for detecting the high water level in the electric kettle through a wire, and is used for automatic quantitative water addition and prevention of water overflow measurement and control.

[0048] Figure 4 The following sequential signal measurement modules solidified in the single-chip computer are shown, and the following timing control device is used for measurement and control, including timing signal (2) (corresponding to step 2 of the method) self-detection signal: first set the program-controlled input / output conversion interface to the strong push-pull output mode, and then the computer controls it to send a high-level pulse detection output signal; timing signal (3) (corresponding to step 2 of the method) self-received detection signal: set the program-controlled input / output conversion interface to the pull-up input mode, and detect the input signal corresponding to the output signal feedback in real time, and compare according to the set logic. In this embodiment 1, when the input signal is detected to be at a high level, it means that there is no water at the water level, and when the input signal state is detected to be at a low level, it corresponds to the water level. The logical correspondence between the high and low levels is determined according to the corresponding detection results of the output and input signals. As for whether the high level corresponds to the water level with or without water, or the low level corresponds to the water level with or without water, it is pre-set by the engineer when designing the circuit and software.

[0049] In order to obtain stable and reliable detection data, the timing signal (2) can be optimized as follows:

[0050] First, the program-controlled input / output conversion interface is set to a strong push-pull output mode, and a certain time t0 is passed to stabilize the strong push-pull output state; then, the computer is programmed to send a pulse detection output signal, and a certain time t1 is passed to stabilize the output signal; then, the computer is programmed to send a low-level detection output signal, and a certain time t2 is passed to stabilize the output signal; the optimized timing signal (3) is: the program-controlled input / output conversion interface is set to a pull-up input mode, a certain time t3 is delayed, so that the input signal corresponding to the output signal feedback is stable, and then the input signal is detected in real time. When the input signal is at a high level, it indicates that there is no water at the water level, and when the input signal is at a low level, it indicates that there is water at the water level.

[0051] The interval times t0, t1, t2, and t3 are experimentally determined within the range of 0-100ms (they can also be determined beyond this range according to actual needs). In this embodiment 1, t0 is experimentally selected within the range of 60-100ms, t1 is experimentally selected within the range of 3-30ms, t2 is experimentally selected within the range of 3-30ms, and t3 is experimentally selected within the range of 3-30ms.

[0052] Embodiment 2:

[0053] A device for measuring and controlling water level, see Figure 2 and Figure 4Taking the intelligent automatic tea art stove as an example, it includes the water containing space 1, which is specifically an electric kettle 2. A metal probe T1 for measuring the high water level is provided on the upper part of the electric kettle 2 (for measuring and controlling the maximum water addition amount). A total of two levels of water level measurement and control are designed: high water level and low water level. Figure 2 , 4 As shown in the figure, the device for self-generated / self-detection and control of water level in this embodiment is a fully automatic intelligent control tea art stove, which includes an electric kettle 2, in which a metal probe T2 for measuring low water level (to prevent the electric kettle from drying out, not heating due to lack of water, and automatically controlling water replenishment) and a metal probe T1 for measuring high water level (to measure and control the highest water level and maximum water addition amount for automatic water addition) are arranged. The metal probe is made of 304 or 316 stainless steel.

[0054] The circuit of the device for self-generated / self-detection and control of water level includes an embedded computer or a single-chip computer MCU, and two program-controlled input / output conversion interfaces I / O1 and I / O2 are arranged on the computer. Among them: one program-controlled input / output conversion interface I / O1 is connected to one end of a series resistance-capacitance branch composed of a capacitor C1 and a resistor R1 in series, and the other end of the series resistance-capacitance branch is connected to a probe T1 for detecting the high water level in the electric kettle through a wire, which is used for automatic quantitative water addition and prevention of water overflow; another program-controlled input / output conversion interface I / O2 is connected to one end of a series resistance-capacitance branch composed of a capacitor C2 and a resistor R2 in series, and the other end of the series resistance-capacitance branch is connected to another probe T2 for detecting the low water level in the electric kettle through a wire, which is used for measurement and control to prevent the electric kettle from drying out due to lack of water and automatic water addition control.

[0055] The ground signal line of the computer is connected to the bottom ground terminal of the electric kettle 2 to be tested, which is made of stainless steel (Note: if the water holding space is a stainless steel barrel or electric kettle, any point of the entire barrel or kettle body can be grounded); the two programmable input / output conversion interfaces I / O1 and I / O2 are conversion interfaces with strong push-pull output mode and pull-up input mode that can be switched by programmable control, forming a device with two-level water level measurement and control.

[0056] The following sequential measurement and control modules are embedded in the single-chip computer MCU, and the measurement and control are carried out according to the following timing control device: (1) Spontaneous detection signal: first set the program-controlled input / output conversion interface to the strong push-pull output mode, and then the computer controls it to send a pulse detection output signal; (2) Self-received detection signal: set the program-controlled input / output conversion interface to the pull-up input mode, and detect the input signal corresponding to the output signal feedback in real time, and compare it according to the set logic. When the input signal is at a high level, it indicates that there is no water at the water level. When the input signal state is at a low level, it indicates that there is water at the water level.

[0057] In order to obtain stable and reliable detection data, the timing signal 1 can be optimized as follows:

[0058] First, the program-controlled input / output conversion interface is set to a strong push-pull output mode, and a certain time t0 is passed to stabilize the strong push-pull output state; then, the computer is programmed to send a high-level detection output signal, and a certain time t1 is passed to stabilize the output signal; then, the computer is programmed to send a low-level detection output signal, and a certain time t2 is passed to stabilize the output signal; the optimized timing signal (2) is: the program-controlled input / output conversion interface is set to a pull-up input mode, a certain time t3 is delayed to stabilize the input signal corresponding to the output signal feedback, and then the input signal is detected in real time. When the input signal is at a high level, it indicates that there is no water at the water level, and when the input signal is at a low level, it indicates that there is water at the water level.

[0059] The interval times t0, t1, t2, and t3 are experimentally determined within 0-100 ms, for example: t0 is 60-100 ms, and t1, t2, and t3 are 3-30 ms.

[0060] The capacitor C1 and the capacitor C2 are high-voltage isolation capacitors, and the withstand voltage can be above AC220V-2000V, which is determined according to the AC power supply. If the power supply is AC110V, it is possible to select AC220V or above, and it is better to select 400V, 600V, 800V, 1000V, 1200V or 2000V. For the AC220V AC power supply, the withstand voltage is preferably 800-1200V. The strong / weak current isolation effect of the capacitor C1 and the capacitor C2 forms a two-way path protection for breakdown leakage in two directions from strong electricity to weak electricity and from weak electricity to strong electricity, which plays an extremely important role in the special application environment in the electric kettle, and is not only related to whether the cost of the product can be accepted by the market, in view of the space limitation of the coupler of the electric kettle, and the special protection of human-machine safety, the strong / weak current isolation effect determines whether the product can pass the mandatory safety certification, and whether it can be allowed to go on the market, which is a difficult problem that has long troubled the industry, and is a major improvement of the utility model.

[0061] Embodiment 3:

[0062] The same principle as the above embodiment, in this embodiment, Figure 3 The circuit schematic diagram of the device for self-generated / self-detecting and controlling water level in the embodiment 3 shows that it can detect three levels of water level, and of course it can be changed to more levels. In this embodiment 3, the functions of the resistor-capacitor series branch formed by the capacitor C3 and a resistor R3 connected in series, and the probe T3 are the same as those of the corresponding components in embodiments 1 and 2, and are used to detect and control the lowest level of water level.

[0063] Embodiment 4:

[0064] Attached Figure 5 , Figure 7 Illustrated in the figure is the basic circuit schematic diagram of another device for sending / detecting independent water level measurement and control and its built-in measurement and control timing, which is also used to detect the first-level water level [one-point water level]: such as full water, highest water level, low water level, etc.

[0065] A device for measuring and controlling water level, in particular a device for independently measuring and controlling water level.

[0066] The device uses a computer's strong push-pull output mode output interface o1 and a corresponding pull-up input mode input interface I1 to send a detection signal through the output interface o1, and then detects the feedback detection signal change through the input interface I1 to detect one or more water levels.

[0067] There is one input interface I1 in the pull-up input mode and one corresponding output interface o1 in the strong push-pull output mode, one to one. The measurement and control sequence is:

[0068] (1) Preparation: Place metal probes T1 corresponding to the number of input interfaces in the water containing space to be measured, connect the bottom of the water containing space to the ground signal line, connect the probe T1 to the pull-up input mode input interface I1 through a wire and a resistor-capacitor series branch formed by a capacitor C1 and a resistor R1 in series, and then connect the probe T1 to the output interface o1 of the strong push-pull output mode through a wire; (2) The output interface o1 of the strong push-pull output mode is controlled by the single-chip computer MCU to send a pulse detection output signal; (3) The input interface I1 of the pull-up input mode controlled by the computer detects the input signal corresponding to the output signal feedback in real time. When the input signal is detected to be at a high level, it indicates that there is water (indicating that the water level has reached this level of water level detection point); when the input signal is detected to be at a low level, there is no water corresponding to the water level (indicating that no water level has reached this level of water level detection point).

[0069] This is based on the principle that capacitors pass AC but block DC. Figure 5 Note: When there is no water in the probe, the pulse signal of the output interface o1 will pass through the resistor Ro1, capacitor Co1, capacitor C1, resistor R1 and input interface I1 to form a loop, and the pin voltage of the input interface I1 will be pulled down, so the measured value is a low level. When there is water in the probe, the pulse signal output by the output interface o1 will pass through the resistor Ro1 and capacitor Co1, but will not pass through the capacitor C1 and resistor R1. The metal probe T1 contacting water is equivalent to connecting a water capacitor and then grounding GND, so the pulse signal will pass through Ro1 and Co1 and then through the water capacitor and ground GND, so the pulse signal is cut off, and the I1 pin voltage will not be pulled down even if there is no signal passing through, and the measured value is a high level.

[0070] The strong push-pull output mode described in this embodiment has only one output interface o1 and only one input interface I1, which is used in various occasions where only one level or one point of water level needs to be measured and controlled.

[0071] In order to make the system measurement and control more stable, the following improvement is made in this embodiment: the pulse detection output signal is generated according to the following timing, the output interface first sends out a high-level detection output signal, and then delays a signal stabilization time Tw1, and then the output interface sends out a low-level detection output signal, and then delays another signal stabilization time Tw2; when the input signal is detected to be at a high level, it indicates that there is water at the water level, and when the input signal is detected to be at a low level, it corresponds to that there is no water at the water level.

[0072] The data stabilization time Tw1 and the data stabilization time Tw2 can be experimentally determined within 0-300 milliseconds, such as selecting: 0, 10, 100, 300 milliseconds.

[0073] The capacitor described in the utility model uses a high-voltage isolation capacitor with a withstand voltage of AC220-2000V, which can prevent the circuit system from strong and weak electricity breakdown and leakage, and protect the system, device and personal safety. The capacitor can be selected according to the actual situation. High-voltage isolation capacitors with a withstand voltage of AC220V, 400V, 600V, 800V, 1000V, 1200V or 2000V.

[0074] Embodiment 5:

[0075] The basic principle of measurement and control is the same as that of Example 4. This example provides a flow chart of a method and device for independently measuring and controlling water levels using an intelligent fully automatic tea art furnace as an example. Figure 5 or attached Figure 7 , the principle of the measurement and control circuit is the same as that of Embodiment 6. Figure 5 This is an example of measuring only the first level of water level. Figure 6 The example shown is that the water level can be measured at three levels: high, medium and low. The detection circuit principle of each level is the same.

[0076] This embodiment measures the two levels of water level of the electric kettle 2: high water level and low water level. The electric kettle of the utility model has the functions of automatic water addition to prevent dry boiling and overflow, and solves the problem that has troubled similar products in the industry for decades: it ensures that electric kettle products can meet the special requirements of safety regulations in the environment of using couplers, and can prevent or reduce the generation of scale and prevent the stainless steel of the joint between the probe and the kettle body from rusting. It is the only technology currently known that can meet safety regulations and have stable performance.

[0077] In this embodiment, there are two pull-up input mode input interfaces: pull-up input mode input interface I1 and pull-up input mode input interface I2 (the drawings are omitted in this embodiment, and the principle is the same as the two-stage water level detection in embodiment 6. The pull-up input mode input interface I2 in this embodiment corresponds to the attached Figure 6 I3 in the embodiment; the capacitor C2 in this embodiment corresponds to the attached Figure 6 In this embodiment, the resistor R2 corresponds to the attached Figure 6 The same is true for R3 in the following. In this embodiment, the capacitor Co2 corresponds to the attached Figure 6 Co3 in the embodiment; the resistor Ro2 corresponds to the attached Figure 6 Ro3 in the strong push-pull output mode, the same below. ); There is only one output interface o1. The measurement and control method and timing are:

[0078] (1) Preparation: Place a metal probe T1 corresponding to a high water level and a metal probe T2 corresponding to a low water level in a stainless steel or glass electric kettle 2 (i.e., water containing space 1) at each water level to be measured. Connect the bottom of the electric kettle 2 to a ground signal line. Connect the two probes to one end of two resistor-capacitor series branches formed by connecting capacitor C1 and resistor R1 in series, and capacitor C2 and resistor R2 in series, respectively, through wires. Then, the other ends of the two resistor-capacitor series branches are respectively connected to the corresponding input interface I1 and input interface I2 of the single-chip computer MCU. Then, connect the two probes to a capacitor Co1 and resistor Ro1 in series, and capacitor Co2 in series, respectively, through wires. One end of the two RC series branches formed by connecting in series with the resistor Ro2 is connected, and then the other ends of the two RC series branches are connected in parallel and connected to the corresponding output interface o1 of the single-chip computer MCU; (2) the output interface o1 of the strong push-pull output mode is controlled by the computer to send a pulse detection output signal; (3) the input interface I1 of the pull-up input mode corresponding to the high water level (overflow) is controlled by the computer to detect in real time the input signal corresponding to the output signal feedback. When the input signal is at a high level, it indicates that there is no water at this water level (indicating that no water level has reached this water level detection point); when the input signal state is at a low level, it corresponds to the presence of water at this water level.

[0079] In this embodiment, in order to make the system measurement and control more stable, this embodiment also makes the following improvements: the pulse detection output signal is generated according to the following timing, the output interface first sends out a high-level detection output signal, and then delays a signal stabilization time Tw1, and then the output interface sends out a low-level detection output signal, and then delays another signal stabilization time Tw2; when the input signal is detected to be a high level, it indicates that there is water at the water level, and when the input signal is detected to be a low level, it corresponds to that there is no water at the water level.

[0080] The data stabilization time Tw1 and the data stabilization time Tw2 can be experimentally determined within 0-300 milliseconds, such as selecting: 0, 10, 100, 300 milliseconds.

[0081] The capacitor described in the utility model uses a high-voltage isolation capacitor with a withstand voltage of AC220-2000V, which can prevent the circuit system from strong and weak electricity breakdown and leakage, and protect the system, device and personal safety. The capacitor can be selected according to the actual situation. High-voltage isolation capacitors with a withstand voltage of AC220V, 400V, 600V, 800V, 1000V, 1200V or 2000V.

[0082] Embodiment 6:

[0083] Figure 6 This is a circuit schematic diagram of a device for independently measuring and controlling water levels. It can be used in many occasions to detect multi-level water levels, such as wine tanks and water towers. 2-30 levels of water levels can be set. Figure 6 The figure below is a typical example of level 3 water level measurement and control.

[0084] Figure 6 The working principle of the corresponding utility model device is the same as that of Example 5, except that there are three input interfaces of the pull-up input mode, and three RC series branches connected thereto (capacitor C1 and resistor R1, capacitor C2 and resistor R2, capacitor C3 and resistor R3), which are used to detect the input signal sent by the output interface and then fed back to it; there is only one output interface of the strong push-pull output mode corresponding to the input interface of the pull-up input mode, which is the shared output interface o1, and there are also three RC series branches (capacitor Co1 and resistor Ro1, capacitor Co2 and resistor Ro2, capacitor Co3 and resistor Ro3), which are used to send detection signals. In view of the fact that the detection method and the corresponding measurement and control program steps are the same as the previously described principles, they will not be repeated.

[0085] In the above embodiment, the capacitance value range is 33-600PF, including 33PF and 600PF, as well as intermediate values. The specific preferred value should be optimized through experiments based on the specific computer port parameters and the measured water parameters. This is a simple and repetitive operation, and this manual will not go into details.

[0086] In summary, the circuit of the utility model uses very few components, especially it can withstand high voltage breakdown and realize strong / weak electricity bidirectional isolation. Because there is no DC voltage on the probe, it will not produce electrolysis on water. The electrode is not easy to rust and scale in a closed, high temperature and high humidity environment, and the performance is very reliable. Especially for electric kettles, electric water boilers, boilers, water dispensers, water tanks, water towers, it can be widely used in extremely small spaces and at low cost. The water level or capacity sensor constructed by the utility model can widely replace the existing liquid level sensors such as float valves.

Claims

1. A device for measuring and controlling water level, characterized in that: The device for measuring and controlling water level includes a computer, on which is provided at least one program-controlled input / output conversion interface, which is connected to a corresponding resistor-capacitor series branch composed of a corresponding number of capacitors and resistors in series, and then connected to a corresponding metal probe through a wire; the ground signal line of the computer is connected to the bottom grounding terminal of the water containing space to be measured; the program-controlled input / output conversion interface is a conversion interface with program-controlled switching of a strong push-pull output mode and a pull-up input mode, forming a device with one or more levels of water level measurement and control.

2. The device for measuring and controlling water level according to claim 1, characterized in that: The capacitor is a high-voltage isolation capacitor, and its withstand voltage is greater than or equal to AC220V.

3. The device for measuring and controlling water level according to claim 1, characterized in that The device for measuring and controlling the water level is any one of a water level sensor, an electric kettle, a tea bar machine, a water dispenser, a boiler, a water tower or a water storage tank.

4. The device for measuring and controlling water level according to claim 2, characterized in that The capacitor is a high voltage isolation capacitor with a withstand voltage value within the range of AC220V-2000V.

5. The device for measuring and controlling water level according to claim 4, characterized in that The capacitor is a high-voltage isolation capacitor with a withstand voltage of AC220V, 400V, 600V, 800V, 1000V, 1200V or 2000V, and the capacitance value of the capacitor is 33-600PF.

6. A device for measuring and controlling water level, characterized in that The device comprises an embedded computer, on which one or more output interfaces of a strong push-pull output mode and one or more corresponding input interfaces of a pull-up input mode are arranged, the output interface sends out a detection signal, and the input interface detects the detection signal fed back by the output interface; corresponding to the number of input interfaces, a corresponding number of metal probes are arranged, the probes are placed in water containing spaces of various water levels to be measured, the bottom of the water containing space is connected to a grounding signal line, each probe is connected in parallel with two resistor-capacitor series branches formed by a capacitor and a resistor in series through a wire, and then the two resistor-capacitor series branches are respectively connected to the output interface and the input interface.

7. The device for measuring and controlling water level according to claim 6, characterized in that: It includes the following measurement and control logic signals: the output interface sends out a pulse detection output signal; the input interface detects the input signal corresponding to the output signal feedback in real time; when the input signal is at a high level, it indicates that there is water at the water level; when the input signal is at a low level, it indicates that there is no water at the water level.

8. The device for measuring and controlling water level according to claim 6, characterized in that: There are a plurality of output interfaces in the strong push-pull output mode, and each of the input interfaces in the pull-up input mode corresponds to one output interface in the strong push-pull output mode.

9. The device for measuring and controlling water level according to claim 6, characterized in that: There are multiple pull-up input mode input interfaces, and there are correspondingly multiple RC series branches connected to them; there is only one strong push-pull output mode output interface corresponding to the pull-up input mode input interface, forming a common output interface, which is connected to the corresponding probe through the corresponding RC series branch.

10. The device for measuring and controlling water level according to claim 6, characterized in that: The capacitance value of the capacitor is 33-600PF, and the capacitor is a high-voltage isolation capacitor with a withstand voltage greater than or equal to AC240V.

11. The device for measuring and controlling water level according to any one of claims 1 to 10, characterized in that: The device for measuring and controlling the water level is any one of a water level sensor, an electric kettle, a tea bar machine, a water dispenser, a boiler, a water tower or a water storage tank.

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