CN111121917A - Glass kettle and capacitive water level detection device and method thereof - Google Patents

Abstract

The invention relates to a glass kettle and a capacitive water level detection device and method thereof, wherein the capacitive water level detection device comprises a high water level sensing disc, a low water level sensing disc and a capacitive detection circuit board, the high water level sensing disc and the low water level sensing disc are two conductive films which are respectively fixedly arranged on the outer wall of a glass kettle body and correspond to the high water level line and the low water level line, the capacitive detection circuit board is arranged on a chassis of the glass kettle body and is electrically connected with a singlechip of the glass kettle, the capacitive detection circuit board is provided with a touch sensing chip, the high water level sensing disc and the low water level sensing disc are respectively and electrically connected with two sensing input ports of the touch sensing chip, the capacitive detection circuit board detects a capacitance value, and comparing the absolute capacitance value interval with the water capacitance value interval preset in the single chip microcomputer or the touch control sensing chip, thereby judging whether the water level of the glass kettle reaches a high water level or a low water level. The invention has simple structure, convenient assembly and disassembly, adopts non-contact detection and has high safety.

Description

Glass kettle and capacitive water level detection device and method thereof

Technical Field

The invention relates to the technical field of kettles, in particular to a glass kettle and a capacitive water level detection device and method thereof.

Background

The existing glass kettle generally comprises an electric heating base and a kettle body, wherein the kettle body is provided with a heating unit, the base is provided with a control circuit, the heating unit is connected with the control circuit through a coupler or is in communication transmission through a wireless communication module, and the kettle body is also provided with a temperature sensor. When the glass kettle is used, the heating unit of the base and the glass kettle body can be connected only by placing the glass kettle on the base, the heating unit can work by pressing the control key on the base, so that water in the glass kettle body is heated, the temperature sensor on the kettle body can transmit the water temperature in the kettle to the base, the power supply is automatically cut off when the water is boiled, and the use is safe and convenient.

However, in the water level display of the existing glass kettle, only the highest water level line and the lowest water level line are marked on the glass kettle body, so that a user can judge the water level by means of manual visual identification, and sometimes, the user fails to pay attention to the water level of the glass kettle in real time due to negligence, so that the danger of water shortage and dry burning or full water adding can occur, and thus, the potential safety hazard exists.

At present, the water level detection of a part of glass teapots is to install electrodes in direct contact with water in the teapot, perform electrode type water level detection by using the conductivity of water, apply certain low voltage to the electrodes, detect the change of voltage through water equivalent to certain resistance and a voltage division circuit, and thus judge whether water exists. However, this method is equivalent to different resistance values due to different water quality and different conductivity, so that different divided voltages are detected, for example, the current passing through the electrodes is small because the equivalent resistance of pure water is large; tap water, which is routinely rich in minerals, has a relatively low resistivity and thus the current through the electrodes can be relatively large. Therefore, the same amount of water generates different currents depending on the water quality, and the voltage difference detected by the voltage divider circuit is large, so that erroneous judgment often occurs. Moreover, the water level probe is installed in the kettle and is in direct contact with water, the water level probe is wrapped by water scale after being used for a long time, and the water level probe is not conductive or has reduced conductivity, so that misjudgment is easy to occur.

Disclosure of Invention

The invention aims to provide a glass kettle and a capacitive water level detection device and method thereof, so as to solve the problems. Therefore, the invention adopts the following specific technical scheme:

according to an aspect of the present invention, there is provided a capacitive water level detection device for a glass kettle, wherein the capacitive water level detection device comprises a high water level sensing plate, a low water level sensing plate and a capacitive detection circuit board, the high water level sensing plate and the low water level sensing plate are two conductive films fixedly mounted on an outer wall of a glass kettle body at positions corresponding to high and low water level lines, respectively, the capacitive detection circuit board is mounted on a chassis of the glass kettle body and electrically connected to a single chip of the glass kettle, the capacitive detection circuit board has a touch sensing chip, the touch sensing chip is a capacitive sensing detection chip capable of accurately detecting capacitance values sensed by the high water level sensing plate and the low water level sensing plate, the high water level sensing plate and the low water level sensing plate are electrically connected to two sensing input ports of the touch sensing chip, respectively, and the capacitive detection circuit board detects the capacitance values through the two sensing input ports of the touch sensing chip, and comparing the absolute capacitance value interval with the water capacitance value interval preset in the single chip microcomputer or the touch control sensing chip, so as to judge whether the water level of the glass kettle reaches a high water level or a low water level.

Furthermore, the high water level induction disc and the low water level induction disc are printed or tightly attached to the outer wall of the glass kettle body, so that the induction discs are tightly contacted with the wall of the glass kettle and keep long-term effectiveness.

Furthermore, the high water level sensing disc and the low water level sensing disc are respectively led to the bottom of the glass kettle body through printed conductive film leads and are respectively and electrically connected to two sensing input ports of the touch sensing chip through two conductive silica gel columns.

Further, the conducting film lead forms an upper contact disc at the bottom of the glass kettle body, and the upper contact disc is reliably contacted with the head of the conducting silica gel column.

Furthermore, the capacitance detection circuit board is provided with a lower contact disc, and the lower contact disc is reliably contacted with the bottom of the conductive silica gel column and is electrically connected with the induction input port.

Furthermore, the conductive silica gel column is arranged on a circular limiting ring capable of rotating 360 degrees, and the circular limiting ring is positioned between the glass kettle body and the chassis. The circular limiting ring can rotate, so that the conductive silica gel column can be conveniently installed and calibrated, the conductive silica gel column is pressed against the conductive film, and the high water level sensing discs and the sensed capacitance change are conveniently and reliably transmitted to the sensing input port of the touch chip of the capacitance type water level detection circuit respectively.

Furthermore, a horn mouth mounting hole is formed in the limiting ring, and the head of the conductive silica gel column is clamped in the horn mouth mounting hole.

Further, the high water level sensing plate and the low water level sensing plate are circular, square or rectangular sensing plates with fixed areas.

According to another aspect of the invention, a glass kettle is provided, which comprises a glass kettle body and an electric heating furnace base which are electrically connected with each other through a coupler or an electromagnetic heating glass kettle and an electromagnetic furnace base which are wirelessly transmitted, wherein a heating unit is arranged in the glass kettle body, the base is provided with a control circuit and a water adding device, the glass kettle is provided with the capacitance type water level detection device, the capacitance detection circuit board is electrically connected with the control circuit arranged on the base through the coupler, the capacitance detection circuit board transmits the obtained water level information to the control circuit, and the control circuit controls the heating unit of the glass kettle to stop heating or the water adding device to stop adding water according to the water level information.

According to another aspect of the present invention, there is also provided a water level detecting method of a glass kettle, comprising the steps of:

obtaining an anhydrous capacitance value interval and a water-containing capacitance value interval through multiple tests, and presetting the anhydrous capacitance value interval and the water-containing capacitance value interval in the single chip microcomputer or the touch control sensing chip;

when no water exists in the glass kettle body, the medium in the inner cavity of the glass kettle body on the inner side of the induction disc is air, and at the moment, the capacitance value measured by the capacitance detection circuit board is in a water-free capacitance value interval, so that the water shortage in the kettle is judged;

when water is added into the glass kettle body and the water level reaches the lowest water level line but does not reach the high water level line, the medium in the glass kettle at the inner side of the low water level sensing disc is water, at the moment, the capacitance value detected by the touch sensing chip of the capacitance detection circuit board through the low water level sensing disc is increased, and when a preset water-containing capacitance value interval is reached, the low water level water existence is judged, and the high water level water shortage is judged;

when continuing to add water and the water level reaches the highest water level line to the internal portion of glass kettle, at this moment, the medium in the inboard glass kettle of high water level response dish and low water level response dish is water, and at this moment, the capacitance value increase that the touch-control response chip of electric capacity detection circuit board detected through high water level response dish reaches the water capacity value interval of predetermineeing, just judges that the low water level has water, and high water level has water.

By adopting the technical scheme, the invention has the beneficial effects that: according to the capacitive water level detection device, the conductive films are respectively printed or pasted on the outer wall of the glass kettle body corresponding to the high water level line and the low water level line to serve as the sensing discs, and the capacitance value change of the sensing discs is detected by the touch sensing chip to judge the water level condition, so that the detection is real-time and accurate, and the capacitive water level detection device is simple in structure, durable and effective and convenient to disassemble and assemble. The detection of the invention is non-contact detection, the reliability is high, the safety factor is higher, the conductive film is installed on the outer wall of the glass kettle body, and is not directly contacted with water, thus being not influenced by scale, and the situation that other substances volatilize into the water and pollute the drinking water in the process of boiling water can not occur, thus keeping the water clean and ensuring the water to be healthier.

Drawings

To further illustrate the various embodiments, the invention provides the accompanying drawings. The accompanying drawings, which are incorporated in and constitute a part of this disclosure, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the embodiments. Those skilled in the art will appreciate still other possible embodiments and advantages of the present invention with reference to these figures. Elements in the figures are not drawn to scale and like reference numerals are generally used to indicate like elements.

FIG. 1 is a perspective view of a glass kettle according to an embodiment of the present invention;

FIG. 2 is a perspective view of the glass kettle and the capacitive water level detecting device shown in FIG. 1, wherein a bottom plate of the glass kettle is partially removed to show an internal structure;

fig. 3 is a perspective view of a high water level sensing plate and a low water level sensing plate of the capacitive water level detecting apparatus shown in fig. 2 and conductive film leads thereof;

FIG. 4 is a schematic view of the installation structure of the conductive silica gel columns and the circular spacing rings of the capacitive water level detecting device shown in FIG. 2, wherein one conductive silica gel column is removed to show a bell-mouth installation hole;

FIG. 5 is a perspective view of a capacitance detecting circuit board of the capacitive water level detecting device shown in FIG. 2;

fig. 6 is a schematic diagram of the capacitance detection circuit of the present invention.

Detailed Description

The invention will now be further described with reference to the accompanying drawings and detailed description.

As shown in fig. 1 to 6, the capacitive water level detecting apparatus for a glass kettle according to the present invention may include a high water level sensing plate 31, a low water level sensing plate 32 and a capacitive detection circuit board 33. The high water level sensing plate 31 and the low water level sensing plate 32 are conductive films fixedly mounted (e.g., printed or adhered) on the outer wall of the glass pot body 1 corresponding to the high water level line H and the low water level line L, respectively. Preferably, the high water level sensing disc 31 and the low water level sensing disc 32 are mounted on the glass kettle body 1 where the handle portion is located, so as not to affect the aesthetic appearance of the glass kettle. The capacitance detection circuit board 33 is installed on the chassis of the glass kettle body 1, is electrically connected with a single chip microcomputer (not shown) of the glass kettle, and is provided with a touch sensing chip 331. The touch sensing chip 331 is a capacitance sensing detection chip capable of accurately detecting capacitance values sensed by the high water level sensing plate 31 and the low water level sensing plate 32. In the embodiment, the saint touch chip SC91F831 is adopted, but the invention is not limited to this type of touch chip, and can also be implemented by using another type of touch chip. The SC91F831 is an enhanced ultra-fast 1T 8051 industrial Flash microcontroller with a built-in capacitive touch key function, and the instruction system is completely compatible with the conventional 8051 product series. At most 10 touch key circuits are integrated in the SC91F831, and other resources further include: 8KB Flash ROM (the internal 256Byte can be used as EEPROM), 512B SRAM, at most 17 GP I/O (containing 11 large current drives), 2 16-bit timers, 1-path IIC serial communication interface SIF, at most 4-path 10-bit high-precision ADC, at most 4-path external fracture (wherein 1-path is double-edge interruption), 2-path 8-bit PWM, internal 1% high-precision 16M Hz oscillator, software UART and other resources. The high water level sensing disc 31 and the low water level sensing disc 32 are led to the bottom of the glass pot body 1 through printed conductive film leads 34, and are electrically connected to two sensing input ports of a touch sensing chip 331 of the capacitance detection circuit board 33 through two conductive silica gel columns 35 respectively. Because the dielectric constant value of the glass kettle body 1 is changed greatly when water exists or does not exist, the capacitance values sensed by the two sensing discs 31 and 32 at high and low water levels are changed obviously when water does not exist or exists in the glass kettle. The capacitance detection circuit board 33 detects capacitance values through the two sensing input ports of the touch sensing chip 331, and compares the capacitance values with a preset anhydrous capacitance value interval, a preset low water level water-containing capacitance value interval and a preset high water level water-containing capacitance value interval in the single chip microcomputer or the touch sensing chip 331, so as to judge whether the water level of the glass kettle reaches a high water level or a low water level.

The capacitance detection device is applied to a glass kettle, the glass kettle can be an electric heating kettle as shown in figure 1, and comprises a glass kettle body 1 and a base 2 which are electrically connected with each other through a coupler, a heating unit is arranged in the glass kettle body 1, the base 2 is provided with a control circuit with a single chip microcomputer and a water adding device 4, and the coupler, the base 2, the heating unit, the control circuit and the water adding device are conventional components and are not further described here. The capacitance detection circuit board 33 is electrically connected with a control circuit installed on the base through a coupler, the capacitance detection circuit board 33 transmits the obtained high and low water level information to the control circuit, and the control circuit controls the heating unit of the glass kettle to stop heating or the water adding device to stop adding water according to the high and low water level information. Certainly, glass kettle can also be electromagnetic induction heating's kettle, including electromagnetic heating glass kettle and electromagnetism stove base through wireless transmission communication, the nonrust steel sheet of magnetic conduction is pasted or is placed to glass kettle body bottom and pass through electromagnetic induction heating, and the base is equipped with control circuit and adds the water installation, the wireless communication module communication can be crossed with the control circuit who installs at the base to electric capacity detection circuitry, and similarly, electric capacity detection circuitry 33 conveys the height water level information that obtains to control circuit, and control circuit stops heating or adds the water installation and stops adding water according to the heating element of height water level information control glass kettle.

In the present embodiment, the high water level sensing plate 31 and the low water level sensing plate 32 are rectangular. In one embodiment, the high water level sensing plate 31 has a length of 13 mm and a width of 10 mm, and the low water level sensing plate 32 has a length of 17 mm and a width of 12 mm. It should be understood that the high water level sensing plate 31 and the low water level sensing plate 32 may be circular or square in other shapes.

In the illustrated embodiment, the high water level sensing plate 31 and the low water level sensing plate 32 are led to the bottom of the glass kettle body through printed conductive film leads 34, and are electrically connected to two sensing input ports of the touch sensing chip 331 of the capacitance detection circuit board 33 through two conductive silica gel columns 35, respectively. In this case, the area of the high water level sensing pad 31 plus its conductive film leads 34 is the same as the area of the low water level sensing pad 32 plus its conductive film leads 34, so that the sensing capacitance thereof is the same. The high water level sensing pad 31 and the low water level sensing pad 32 may be electrically connected to two sensing input ports of the touch sensing chip 331 of the capacitance detection circuit board 33 through thin wires. In this case, the water level sensing plate 31 and the low water level sensing plate 32 have the same size.

In order to ensure a reliable electrical connection of the conductive silica gel column 35 to the conductive film wire 34, the conductive film wire 34 forms an upper contact pad 341 at the bottom of the glass kettle body. The upper contact disc 341 keeps a safety distance of more than 3 mm from the heating metal of the glass pot body 1. Preferably, the width of the conductive film leads 34 is 1.2 millimeters; and the upper contact pad 341 has a width of 1.5-2 mm and a length of 4 mm, so that the area of the conductive film lead 34 is much smaller than the areas of the high water level sensing pad 31 and the low water level sensing pad 32, thereby preventing the water level from being detected by mistake.

Similarly, in order to ensure reliable electrical connection between the conductive silica gel column 35 and the capacitance detection circuit board 33, the capacitance detection circuit board 33 is provided with a lower contact pad 332, and the lower contact pad 332 is electrically connected to the sensing input port. In order to minimize the area of the lower contact pad 332, it is preferable that the lower contact pad 332 is a circular rectangular copper-clad conductive layer having a width of 2 mm and a length of about 6 mm, and the copper-clad surface is plated with a material for preventing rust, such as gold plating, silver plating, or tin plating. This is for convenient installation counterpoint, because the circuit board installation and the installation of conductive silica gel all can have the position deviation in the production process of production, but the deviation is not too big, normally controls to be at the left and right sides displacement and does not exceed 3 millimeters.

As shown in fig. 2 and 4, the conductive silica gel column 35 is mounted on a circular spacing collar 36 capable of rotating 360 degrees, and the spacing collar 36 can rotate left and right, so that the alignment is convenient to adjust. Two bell mouth mounting holes 361 are respectively arranged on the limiting ring 36, so that the conductive silica gel column 35 can be conveniently mounted at a countersunk position. The conductive silica gel column 35 is provided with a T-shaped structure with a cap, so that the conductive silica gel column is prevented from sinking when the upper contact disc 341 is pressed, and a limiting effect is achieved, namely, the head of the conductive silica gel column 35 is clamped in the bell mouth mounting hole 361. Thus, the conductive silica gel column 35 and the upper contact pad 341 can be reliably pressed and contacted and can be kept effective for a long time.

In order to facilitate the mounting of the capacitance detection circuit board 33, a circuit board mounting box 37 is further provided. The circuit board mounting box 37 is further provided with a limiting device 371, and the limiting device 371 is used for preventing the conductive silica gel column 35 from deviating in the process of jacking the upper contact disc 341 and the lower contact disc 332, so as to ensure that the conductive silica gel column 35 is reliably contacted with the upper contact disc 341 and the lower contact disc 332.

According to an embodiment of the present invention, there is also provided a water level detection method for a glass hot water kettle as described above, including the steps of:

step 1: when a plurality of glass thermos kettles are tested in the absence of water in advance, the capacitance values detected by the touch sensing chip SC91F831 through the high-low water level sensing discs 31 and 32 are recorded and converted into an AD value (generally, hexadecimal is adopted), and the AD value in the interval is preset as an anhydrous capacitance value interval.

Step 2: various kinds of water are filled into different glass thermos kettles in advance, the capacitance value detected by the touch sensing chip SC91F831 through the high-low water level sensing disc is tested and recorded, the capacitance value is converted into an AD value through an algorithm, and the AD value in the interval is preset as a water capacitance value interval.

And step 3: tests show that when the touch sensing chip SC91F831 is used for detecting the touch ports of high and low water levels, a short-circuit fault exists in the capacitance detection circuit, and the AD value in the interval is set as a fault condition E1 capacitance value interval, for example, when the glass thermos is in operation, the glass thermos stops working when the AD values of the two touch ports of the touch sensing chip SC91F831 used for detecting high and low water levels are in the interval, and a fault code E1 is displayed through a display window, so that the fault self-detection effect is achieved.

And 4, step 4: tests show that when the touch sensing chip SC91F831 is used for detecting the touch ports of high and low water levels, the capacitance detection circuit has an open circuit fault, and the AD value in the interval is set as a fault condition E2 capacitance value interval, for example, when the glass thermos is in operation, the glass thermos stops working when the AD values of the two touch ports of the touch sensing chip SC91F831 used for detecting high and low water levels are in the interval, and the fault code E2 is displayed through the display window, so that the fault self-detection effect is achieved.

The detection results in the steps 1, 2, 3 and 4 are that an anhydrous capacitance value interval, a water capacitance value interval, a fault condition E1 capacitance value interval and a fault condition E2 capacitance value interval are obtained, the absolute capacitance value interval, the water capacitance value interval, the fault condition E1 capacitance value interval and the fault condition E2 capacitance value interval are recorded in a single chip microcomputer (a memory) of a touch sensing chip SC91F831 or a glass thermos bottle in actual production and are used as an anhydrous or hydrated judgment reference and a fault condition E1 and a fault condition E2 judgment reference, and a client does not need to perform test setting in actual use. The human-machine operation interface can also be used for fine adjustment of a water capacitance value interval, a water-free capacitance value interval, a fault E1 capacitance value interval and a fault E2 capacitance value interval, and after fine adjustment, the fine adjustment can be confirmed to be stored in a memory to be used as various calibrated judgment reference capacitance value intervals.

When the glass kettle body 1 is empty of water, the medium in the glass kettle of the high and low water level sensing discs 31 and 32 is air, and at the moment, the capacitance value measured by the capacitance detection circuit board 33 is within a preset anhydrous capacitance value interval, and it is judged that the water level in the kettle does not reach the low water level position and the high water level position. Namely, the low water level and the high water level are both lack of water, and the heating unit is controlled by the control circuit to stop heating.

When water is added into the glass kettle body 1 and the water level reaches the lowest water level line, the medium in the glass kettle, which is tightly attached to the low water level sensing disc 32, is water, at the moment, the capacitance detected by the capacitance detection circuit board 33 is increased, and reaches a preset capacitance value interval with water, and then the water level in the kettle reaches the low water level line, and then the low water level is judged to have water.

When water is added into the glass kettle body 1 and the water level reaches the highest water level line, the medium in the glass kettle tightly attached to the high water level induction disc 31 is water, at the moment, the capacitance detected by the capacitance detection circuit board 33 is increased, the interval of the capacitance value of water is reached, the water at the low water level is judged, the water at the high water level is also water, the water filling can be judged, and the water adding is stopped under the control of the control circuit.

Therefore, according to water level information, intelligent water adding can be achieved, water can be stopped when the water is filled, water can be heated intelligently, water cannot be heated when no water exists, and dry heating is prevented. Meanwhile, the invention can also add a graphic which displays the water level of the kettle on the display screen of the base, is convenient for customers to use water, and can automatically determine whether water needs to be added or not and use water according to the water quantity.

While the invention has been particularly shown and described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims (10)

1. The utility model provides a capacitanc water level detection device of glass kettle which characterized in that: capacitanc water level detection device includes high water level response dish, low water level response dish and electric capacity detection circuitry board, high water level response dish and low water level response dish are two conductive film of corresponding high, low water level department on the outer wall of the glass kettle body respectively fixed mounting, electric capacity detection circuitry board install on the chassis of the glass kettle body and with the monolithic is electromechanical connection of glass kettle, have touch-control response chip, touch-control response chip is for can accurately detecting out the electric capacity response detection chip of the capacitance value that high water level response dish and low water level response dish sensed, high water level response dish and low water level response dish be electric connection respectively two response input ports of touch-control response chip, electric capacity detection circuitry board passes through two response input ports of touch-control response chip detect the capacitance value, and with the singlechip or in the touch-control response chip in the anhydrous capacitance value interval of predetermineeing with have water capacitance value interval to act on to between the water capacitance value And then judging whether the water level of the glass kettle reaches a high water level or a low water level.

2. The capacitive water level detecting apparatus of a glass kettle as set forth in claim 1, wherein: the high water level induction disc and the low water level induction disc are printed or tightly attached to the outer wall of the glass kettle body.

3. The capacitive water level detecting apparatus of a glass kettle as set forth in claim 2, wherein: the high water level induction disc and the low water level induction disc are respectively led to the bottom of the glass kettle body through printed conductive film leads and are respectively and electrically connected to two induction input ports of the touch induction chip through two conductive silica gel columns.

4. The capacitive water level detecting apparatus of a glass kettle as set forth in claim 3, wherein: the conductive film lead forms an upper contact disc at the bottom of the glass kettle body, and the upper contact disc is reliably contacted with the head of the conductive silica gel column.

5. The capacitive water level detecting apparatus of a glass kettle as set forth in claim 4, wherein: and a lower contact disc is arranged on the capacitance detection circuit board, and the lower contact disc is reliably contacted with the bottom of the conductive silica gel column and is electrically connected with the induction input port.

6. The capacitive water level detecting apparatus of a glass kettle as set forth in claim 3, wherein: the conductive silica gel column is arranged on a circular limiting ring which can rotate by 360 degrees, and the circular limiting ring is positioned between the glass kettle body and the chassis.

7. The capacitive water level detecting apparatus of a glass kettle as set forth in claim 6, wherein: the limiting ring is provided with a horn mouth mounting hole, and the head of the conductive silica gel column is clamped in the horn mouth mounting hole.

8. The capacitive water level detecting apparatus of a glass kettle as set forth in claim 1, wherein: the high water level induction disc and the low water level induction disc are circular, square or rectangular induction discs with fixed areas.

9. The utility model provides a glass kettle, includes the glass kettle body and the electric heater base that are connected through the mutual electricity of coupler or through wireless transmission's electromagnetic heating glass kettle and electromagnetism stove base, is equipped with the unit that generates heat in the glass kettle body, and the base is equipped with the control circuit who takes the singlechip and adds water installation, its characterized in that: the glass kettle is provided with the capacitance type water level detection device as claimed in any one of claims 1 to 8, the capacitance detection circuit board is electrically connected with a control circuit arranged on the base through a coupler, the capacitance detection circuit board transmits obtained water level information to the control circuit, and the control circuit controls a heating unit of the glass kettle to stop heating or a water adding device to stop adding water according to the water level information.

10. The water level detecting method of a glass kettle as claimed in claim 9, comprising the steps of:

obtaining an anhydrous capacitance value interval and a water-containing capacitance value interval through multiple tests, and presetting the anhydrous capacitance value interval and the water-containing capacitance value interval in the single chip microcomputer or the touch control sensing chip;

when no water exists in the glass kettle body, the medium in the inner cavity of the glass kettle body on the inner side of the induction disc is air, and at the moment, the capacitance value measured by the capacitance detection circuit board is in a water-free capacitance value interval, so that the water shortage in the kettle is judged;

when water is added into the glass kettle body and the water level reaches the lowest water level line but does not reach the high water level line, the medium in the glass kettle at the inner side of the low water level sensing disc is water, at the moment, the capacitance value detected by the touch sensing chip of the capacitance detection circuit board through the low water level sensing disc is increased, and when a preset water-containing capacitance value interval is reached, the low water level water existence is judged, and the high water level water shortage is judged;

when continuing to add water and the water level reaches the highest water level line to the internal portion of glass kettle, at this moment, the medium in the inboard glass kettle of high water level response dish and low water level response dish is water, and at this moment, the capacitance value increase that the touch-control response chip of electric capacity detection circuit board detected through high water level response dish reaches the water capacity value interval of predetermineeing, just judges that the low water level has water, and high water level has water.

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