NTC (Negative Temperature Coefficient) contact type electric kettle

Abstract

The utility model provides an NTC (Negative Temperature Coefficient) contact type electric kettle which is characterized by comprising a kettle body part, a heating part and a base, the heating part can be placed on the base, and the kettle body part and the heating part are of an integrated structure; at least one sensor is arranged on the upper end surface of the heating part; the sensor extends into the kettle body part; a detection module and a heating module are arranged in the heating part; a power module and a main control module are arranged in the base; the detection module is respectively connected with the sensor and the main control module through connecting wires; the main control module is respectively connected with the power supply module and the heating module through connecting wires; the heating module can heat liquid stored in the kettle body part; the detection module is used for detecting the temperature and liquid level of liquid stored in the kettle body part; the sensor comprises an NTC (Negative Temperature Coefficient) metal shell, a silica gel isolation pad and a liquid level detection line, the silica gel isolation pad is arranged on the upper end face of the heating part, the NTC metal shell is fixed to the upper portion of the silica gel isolation pad, and the liquid level detection line penetrates through the silica gel isolation pad to be connected with the NTC metal shell.

Description

Technical Field

[0001] The present application relates to the technical field of electric kettles, and in particular to an NTC contact electric kettle. Background Art

[0002] An electric kettle is an electrical appliance that heats drinking water or beverages to a drinkable state. It is generally used in hotels, guest rooms, homes, etc. as an electric water boiler for guests to boil water by themselves. It usually has a split power base and an automatic switch when the water boils.

[0003] Existing electric kettles usually do not have an anti-dumping function during use, which causes the electric kettle to easily tip over when touched by foreign objects, causing hot water to flow everywhere, which can easily create a safety hazard. In addition, due to the single structure, the liquid level of the hot water inside the electric kettle cannot be monitored in real time, reducing the applicability of the electric kettle.

[0004] In addition, there are many types of liquid level sensors currently used in the market, including float type, photoelectric type, capacitive type, ultrasonic type, etc., each of which has its own advantages and disadvantages. Any object has capacitance, and the capacitance is related to the dielectric constant and volume size. The liquid level sensor determines the height of the liquid or the presence of liquid by detecting changes in the capacitance of the object. After the liquid level sensor is placed close to the container wall, a capacitor similar to parallel plates is formed between it and the liquid. The capacitance value of this capacitor is affected by the interaction area between the liquid and the sensor and the dielectric constant of the container wall. Utility Model Content

[0005] In order to solve the above technical problems, the present application proposes an NTC contact electric kettle, which is characterized in that it includes: a kettle body, a heating part and a base; the heating part can be placed on the base, and the kettle body and the heating part are an integrated structure; at least one sensor is arranged on the upper end surface of the heating part; the sensor extends into the interior of the kettle body; a detection module and a heating module are arranged in the heating part; a power module and a main control module are arranged in the base; the detection module is connected to the sensor and the main control module respectively through wiring; the main control module is connected to the power module and the heating module respectively through wiring; the heating module can heat the liquid stored in the kettle body; the detection module is used to detect the temperature and liquid level of the liquid stored in the kettle body; the sensor includes: an NTC metal shell, a silicone isolation pad, and a liquid level detection line; the silicone isolation pad is arranged on the upper end surface of the heating part, and the NTC metal shell is fixed above the silicone isolation pad, and the liquid level detection line passes through the isolation silicone pad to connect the NTC metal shell.

[0006] The present application is further configured such that the detection module includes: a temperature detection circuit and a liquid level detection circuit; the input ends of the temperature detection circuit and the liquid level detection circuit are respectively connected to sensors, and the output ends of the temperature detection circuit and the liquid level detection circuit are respectively connected to the main control module.

[0007] Through the above technical solution, the detection signal transmitted by the sensor is transmitted to the main control module through the liquid level detection circuit and the temperature detection circuit to monitor the temperature and liquid level of the liquid in the kettle body to avoid dry burning.

[0008] The present application is further configured such that the liquid level detection circuit includes: a capacitive liquid level detection chip, a capacitive comparison circuit, a charge collector, a discharge circuit, an open-drain output circuit, and a decoupling circuit; the sensor is connected to the capacitive liquid level detection chip, and the capacitive liquid level detection chip is respectively connected to the open-drain output circuit, the capacitive comparison circuit, the discharge circuit, the charge collector, and the decoupling circuit.

[0009] Among them, the capacitive liquid level detection chip is mainly used to collect the capacitance of the liquid level detection sensor and the capacitance of the capacitance comparison circuit channel, and obtain high and low level signal outputs through internal logic processing.

[0010] The present application is further configured such that the sensor is connected to the capacitive liquid level detection chip via R3, and the resistor R3 is used to improve the conduction anti-interference and radiation anti-interference.

[0011] The present application is further configured such that the charge collector includes a CMOD capacitor for collecting changes in all parasitic capacitances attached to the capacitive sensor; and the discharge circuit includes a CDC discharge capacitor for discharging the CMOD capacitor.

[0012] The present application is further configured as a capacitance comparison circuit, comprising a capacitor C1, one end of the capacitor C1 being grounded, and the other end being connected to a capacitive liquid level detection chip via R1.

[0013] The present application is further configured such that the open-drain output circuit is output to an external host device through R4, and needs to be connected to the power supply terminal of the capacitive liquid level detection chip through a pull-up resistor R2.

[0014] The present application is further configured such that the decoupling circuit includes a capacitor C2, and two ends of the capacitor C2 are respectively connected to a power supply end and a ground end of the capacitive liquid level detection chip.

[0015] The present application is further configured such that the charge collector is used to collect the change in all parasitic capacitances attached to the sensor, and compares it with the internal comparator of the capacitive liquid level detection chip. When the change exceeds the reference voltage set inside the capacitive liquid level detection chip, the CDC discharge capacitor selection switch is turned on inside the capacitive liquid level detection chip to discharge the CMOD capacitor.

[0016] The present application is further configured such that the capacitive liquid level detection chip converts analog quantities of all additional parasitic capacitance values ​​on the sensor channel and all additional parasitic capacitance values ​​on the capacitance comparison circuit channel into digital quantities of the number of switching times of the CDC discharge capacitance selection switch through a charge and discharge mode.

[0017] The beneficial effects of the present application are: since the sensor extends into the kettle body, compared with non-contact heating kettles, the present application can detect the liquid level and temperature of the liquid in the kettle body more accurately and quickly; and the kettle body and the heating part adopt an integrated structure, which is more conducive to achieving a lightweight design. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings are included to provide a further understanding of the embodiments and are incorporated into and constitute a part of this specification. The accompanying drawings illustrate the embodiments and are used together with the description to explain the principles of the present application. It will be easy to recognize other embodiments and many expected advantages of the embodiments because they become better understood by reference to the following detailed description. The elements of the drawings are not necessarily to scale with each other. The same reference numerals refer to corresponding similar parts.

[0019] Figure 1 is a schematic structural diagram of an NTC contact electric kettle according to an embodiment of the present application;

[0020] Figure 2 is a block diagram of a liquid level detection circuit of an NTC contact electric kettle according to an embodiment of the present application;

[0021] Figure 3 is a circuit diagram of a liquid level detection circuit of an NTC contact electric kettle according to an embodiment of the present application;

[0022] Figure 4 It is a circuit principle block diagram of an NTC contact electric kettle according to an embodiment of the present application;

[0023] Figure 5 It is a schematic diagram of the structure of a sensor of an NTC contact electric kettle according to an embodiment of the present application.

[0024] The meaning of the numbers in the figure:

[0025] 1. Pot body; 2. Sensor; 2a. NTC metal shell; 2b. Silicone isolation pad; 2c. Liquid level detection line; 2d. VCC / GND connection; 2e. NTCOUT connection; 3. Heating part; 4. Discharge circuit; 5. Open-drain output circuit; 6. Decoupling circuit; 7. Charge collector; 8. Capacitive liquid level detection chip; 9. Capacitor comparison circuit; 10. Filter circuit; 11. Base. DETAILED DESCRIPTION

[0026] In the following detailed description, reference is made to the accompanying drawings, which form a part of the detailed description and are shown by illustrative specific embodiments in which the present application can be practiced. To this end, directional terms, such as "top", "bottom", "left", "right", "up", "down", etc., are used with reference to the orientation of the figures described. Because the components of the embodiments can be positioned in several different orientations, directional terms are used for the purpose of illustration and are by no means limiting. It should be understood that other embodiments may be utilized or logical changes may be made without departing from the scope of the present application. Therefore, the following detailed description should not be adopted in a limiting sense, and the scope of the present application is defined by the appended claims.

[0027] Figure 1 is a schematic diagram of the structure of an NTC contact electric kettle according to an embodiment of the present application, Figure 4 The circuit principle block diagram of an NTC contact electric kettle according to an embodiment of the present application is shown in FIG. Figure 5 is a schematic diagram of the structure of a sensor of an NTC contact electric kettle according to an embodiment of the present application, such as Figure 1 , Figure 4 and Figure 5 As shown, an NTC contact electric kettle comprises:

[0028] A kettle body 1, a heating part 3 and a base 11; the heating part 3 can be placed on the base 11, and the kettle body 1 and the heating part 3 are an integrated structure; at least one sensor 2 is arranged on the upper end surface of the heating part 3; the sensor 2 extends into the kettle body 1; a detection module and a heating module are arranged in the heating part 3; a power module and a main control module are arranged in the base 11; the detection module is connected to the sensor 2 and the main control module respectively through wiring; the main control module is connected to the power module and the heating module respectively through wiring; the heating module can heat the liquid stored in the kettle body 1; the detection module is used to detect the temperature and liquid level of the liquid stored in the kettle body 1; the sensor 2 includes: an NTC metal shell 2a, a silicone isolation pad 2b, and a liquid level detection line 2c; the silicone isolation pad 2b is arranged on the upper end surface of the heating part 3, and the NTC metal shell 2a is fixed above the silicone isolation pad 2b, and the liquid level detection line 2c passes through the isolation silicone pad to connect the NTC metal shell 2a.

[0029] The detection module includes: a temperature detection circuit and a liquid level detection circuit; the input ends of the temperature detection circuit and the liquid level detection circuit are respectively connected to the sensor 23, and the output ends of the temperature detection circuit and the liquid level detection circuit are respectively connected to the main control module.

[0030] Figure 2 is a block diagram of a liquid level detection circuit of an NTC contact electric kettle according to an embodiment of the present application, such as Figure 2As shown, the liquid level detection circuit includes: a capacitive liquid level detection chip, a capacitive comparison circuit 9, a charge collector 7, a discharge circuit 4, an open-drain output circuit 5, and a decoupling circuit 6; the sensor 2 is connected to the capacitive liquid level detection chip 8, and the capacitive liquid level detection chip 8 is respectively connected to the open-drain output circuit 5, the capacitive comparison circuit 9, the discharge circuit 4, the charge collector 7, and the decoupling circuit 6.

[0031] The threshold value of the capacitive liquid level detection chip 8 is set internally by the liquid level chip, or is set internally after collecting external data. Both applications are within a limited range.

[0032] Take SC01 chip as an example, combined with Figure 3 As shown, sensor 2 is connected to CIN2 of capacitive liquid level detection chip 8 through resistor R3, and sensor 2 includes: NTC metal shell 2a, silicone isolation pad 2b, liquid level detection line 2c; silicone isolation pad 2b is arranged on the upper end surface of heating part 3, and NTC metal shell 2a is fixed above silicone isolation pad 2b, liquid level detection line 2c passes through isolation silicone pad to connect NTC metal shell 2a, and NTC metal shell 2a is also connected with VCC / GND connection 2d and NTCOUT connection 2e; general sensor 22 design requires a certain sensing area, preferably a rectangular area, sensor 2 should be designed as large as possible, and sensor 22 parasitic capacitance should be as small as possible, controlled within 10PF, and the sensing area should be designed as large as possible between 4*4mm-30*30mm, ensuring a large sensing area, so as to ensure high sensitivity and high accuracy. Sensor 2 collects the change of capacitance caused by the change of liquid level, and the change is introduced by a resistor R3 to make a logical judgment inside the liquid level chip. The resistor R3 is mainly used to improve the conducted anti-interference and radiated anti-interference, etc., which is helpful for the EMC performance of the product. The selection range is between 0-10KΩ, and the generally recommended value is 3KΩ. In other optional implementations, other types of sensors 2 can also be used.

[0033] More specifically, the decoupling circuit 6 and the filter circuit 10 need to strengthen the EMC and other interference issues in different power supply environments. The decoupling circuit 6 includes a capacitor C2, and the generally recommended value is 100nF; the filter circuit 10 includes a large capacitor C3 connected in series between the power supply and the ground, including a front-end power supply connection inductor L1 / magnetic beads or a ground line connected in series inductor / magnetic beads. The selection of components of these circuits is determined according to the characteristics of the power supply;

[0034] The open-drain output circuit 5 requires an external pull-up resistor R2 for the open-drain output, and the series resistor R4 is mainly used to protect the capacitive liquid level detection chip 8 to prevent external voltage from being applied and large current from being reversed to damage the capacitive liquid level detection chip 8. When it is detected that there is liquid or the liquid level reaches the position to be measured, the output is a low level. When it is detected that there is no liquid or the liquid level is not as high as the position to be measured, the output is a low level. In this application, the output level can be changed according to the needs, and circuits such as inverters can be added to change the output level signal;

[0035] The charge collector 7 includes a CMOD capacitor, the CMOD capacitor value is generally set at 1nF to 10nF, and the recommended value is 4.7nF. It is used to collect the change of all parasitic capacitances attached to the capacitance sensor 23;

[0036] The discharge circuit 4 includes a CDC capacitor, which is used to discharge the CMOD charge collector 77. The capacitor is mainly used to adjust the sensitivity of the sensor 2 to the liquid. The smaller the CDC capacitor, the more sensitive it is to the liquid, and vice versa. The CDC capacitor adjustment range is generally between 5PF-50PF. Using NPO material or COG material, the higher the accuracy and the better the consistency;

[0037] Capacitor comparison circuit 9, including capacitor C1, can be connected in series with a resistor R1 between C1 and CIN1 channels to enhance anti-interference and stability. Serial capacitor C1 needs to use high-precision capacitors. The accuracy of the capacitor directly determines the accuracy of liquid level detection. Considering some complex and changeable conditions, such as high temperature and high humidity environments, capacitors with less temperature drift coefficients should be used as much as possible, and NPO material capacitors should be used as much as possible. This capacitor is to match the current environment and form a difference with the capacitance of the sensor 2 electrode to determine whether the liquid changes, that is, the sensor 2 capacitance value minus the C1 capacitance value is greater than the set threshold value, to determine whether the container liquid level changes, or whether the container has water changes. Generally, the C1 capacitor needs to use NPO material capacitors, and the accuracy level should be as high as possible. The value range is determined by the parasitic capacitance of sensor 2. It is generally recommended to design between 0PF-10PF, and the specific design value is determined by the PCB layout and sensor 2.

[0038] In addition, in this embodiment, there is no restriction on the model of the sensor 2 .

[0039] Obviously, those skilled in the art can make various modifications and changes to the embodiments of the present application without departing from the spirit and scope of the present application. In this way, if these modifications and changes are within the scope of the claims of the present application and their equivalents, the present application is also intended to cover these modifications and changes. The word "comprising" does not exclude the presence of other elements or steps not listed in the claims. The simple fact that certain measures are recorded in mutually different dependent claims does not indicate that the combination of these measures cannot be used to profit. Any figure mark in the claims should not be considered to limit the scope.

Claims

1. An NTC contact electric kettle, characterized in that: include: A kettle body, a heating part and a base; the heating part can be placed on the base, and the kettle body and the heating part are an integrated structure; at least one sensor is arranged on the upper end surface of the heating part; the sensor extends into the interior of the kettle body; a detection module and a heating module are arranged in the heating part; a power module and a main control module are arranged in the base; the detection module is connected to the sensor and the main control module respectively through wiring; the main control module is connected to the power module and the heating module respectively through wiring; the heating module can heat the liquid stored in the kettle body; the detection module is used to detect the temperature and liquid level of the liquid stored in the kettle body; the sensor comprises: an NTC metal shell, a silicone isolation pad, and a liquid level detection line; the silicone isolation pad is arranged on the upper end surface of the heating part, and the NTC metal shell is fixed above the silicone isolation pad, and the liquid level detection line passes through the silicone isolation pad to connect the NTC metal shell.

2. The NTC contact electric kettle according to claim 1, characterized in that: The detection module includes: a temperature detection circuit and a liquid level detection circuit; the input ends of the temperature detection circuit and the liquid level detection circuit are respectively connected to the sensors, and the output ends of the temperature detection circuit and the liquid level detection circuit are respectively connected to the main control module.

3. The NTC contact electric kettle according to claim 2, characterized in that: The liquid level detection circuit includes: a capacitive liquid level detection chip, a capacitive comparison circuit, a charge collector, a discharge circuit, an open-drain output circuit, and a decoupling circuit; the sensor is connected to the capacitive liquid level detection chip, and the capacitive liquid level detection chip is respectively connected to the open-drain output circuit, the capacitive comparison circuit, the discharge circuit, the charge collector, and the decoupling circuit.

4. The NTC contact electric kettle according to claim 3, characterized in that: The sensor is connected to the capacitive liquid level detection chip through R3, and the resistor R3 is used to improve the conduction anti-interference and radiation anti-interference.

5. The NTC contact electric kettle according to claim 4, characterized in that: The charge collector includes a CMOD capacitor, which is used to collect the change of all parasitic capacitances attached to the capacitance sensor; the discharge circuit includes a CDC discharge capacitor, which is used to discharge the CMOD capacitor.

6. The NTC contact electric kettle according to claim 5, characterized in that: The capacitance comparison circuit comprises a capacitor C1, one end of which is grounded, and the other end of which is connected to a capacitive liquid level detection chip via R1.

7. The NTC contact electric kettle according to claim 6, characterized in that: The open-drain output circuit is output to the external host device through R4, and needs to be connected to the power supply terminal of the capacitive liquid level detection chip through the pull-up resistor R2.

8. The NTC contact electric kettle according to claim 7, characterized in that: The decoupling circuit includes a capacitor C2, and two ends of the capacitor C2 are respectively connected to a power supply end and a ground end of the capacitive liquid level detection chip.

9. The NTC contact electric kettle according to claim 8, characterized in that: The charge collector is used to collect the change in all parasitic capacitances attached to the sensor, and compares it with the internal comparator of the capacitive liquid level detection chip. When it exceeds the reference voltage set inside the capacitive liquid level detection chip, the CDC discharge capacitor gating switch inside the capacitive liquid level detection chip is turned on to discharge the CMOD capacitor.

10. The NTC contact electric kettle according to claim 9, characterized in that: The capacitive liquid level detection chip converts analog quantities of all additional parasitic capacitance values ​​on the sensor channel and all additional parasitic capacitance values ​​on the capacitance comparison circuit channel into digital quantities of the number of switching times of the CDC discharge capacitance gating switch through the charge and discharge mode.

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