WO2008031253A1

WO2008031253A1 - Intelligent glass electric heating kettle

Info

Publication number: WO2008031253A1
Application number: PCT/CN2006/002069
Authority: WO
Inventors: I Feng Lin
Original assignee: Mr Technology (Int'l) Ltd.
Priority date: 2006-08-15
Filing date: 2006-08-15
Publication date: 2008-03-20

Abstract

A glass electric heating kettle (1) includes heating portion made of resistance film on the outer surface at the bottom of the glass kettle, and control portion electrically connected with the resistance film (2). The said control portion includes a microcomputer processor with preset control programs, a control panel (4) which has control and input keys and may be inputted work instructions and set temperatures by users, and water temperature sensor (7) set on the region without resistance film on the outer surface at the bottom of the glass kettle. The temperatures detected by the water temperature sensor (7) are transferred to the microcomputer processor, and the microcomputer processor sends control signals according to the inputted work instructions and the set temperatures.

Description

Intelligent glass electric kettle

The invention relates to an electric kettle, in particular to a smart glass electric kettle controlled by a microcomputer. Background technique

A variety of electric kettles are currently on the market for sale. The general electric kettle is designed to have a constant temperature within a certain temperature range according to the needs of the user. In the prior art, dual metal sensors are used to achieve this function. The working principle is to utilize the characteristics of different expansion coefficients of the bimetal. When the temperature rises beyond a certain range of the set value, the bimetal expansion is separated due to the difference in the magnitude of the bimetal expansion, thereby causing the circuit to be disconnected and stopping the heating; The expanded metal shrinks, and when it is shrunk to the same length of the bimetal, the circuit is turned on and heating is continued. Therefore, the prior art electric kettle often only maintains the constant temperature within the range of ±10 ° C, and it is difficult to achieve long-term, accurate constant temperature control.

In addition, with the development of new surface heating technology in recent years, heating resistor films have been widely used in various electric heating products. The electric hot water of glass is an example. At present, the commercially available glass electric kettle also adopts the above-mentioned bimetal temperature control mechanism. In addition, a common problem with the existing glass electric kettle using the resistive film is that due to the production process, the bottom of the glass electric kettle always has some small undulations, which is not flat, so that once there is a point to dry, The existing material of the glass kettle will burst immediately. Summary of the invention

In order to overcome various problems existing in the prior art, it is an object of the present invention to provide a glass electric kettle using a resistive film capable of achieving long-term and accurate temperature control.

Another object of the present invention is to provide a glass electric kettle which can provide effective dry burning protection.

In order to achieve the above object, a glass electric kettle of the present invention comprises a glass kettle, a resistive film heating portion applied to an outer surface of a bottom portion of the glass bottle, and a control portion electrically connected to the resistive film, wherein the control portion includes a pre-installed control program a microcomputer processor, a control panel having a control input key and a user inputting a work command and a set temperature, and a top surface provided on the bottom of the glass kettle is not applied The water temperature sensor on the area where the resistive film is applied, the temperature sensed by the water temperature sensor is transmitted to the microcomputer processor, and the microcomputer processor issues a control signal according to the input work command and the set temperature.

A dry-burning temperature sensor is also disposed on the area where the resistive film is applied to the outer surface of the bottom surface of the glass kettle. When the dry burning occurs, the monitoring signal is transmitted to the microcomputer processor, and the microcomputer processor sends a control signal to cut off the power.

The basic working procedures of the glass electric kettle of the invention include active dry burning detection, boiling heating, ordinary heating, and active dynamic constant temperature.

The electrothermal glass kettle of the present invention can achieve long-term, accurate temperature control and can provide effective dry burning protection as compared with the prior art. DRAWINGS

The invention will be described in detail below with reference to the accompanying drawings, in which:

Figure 1 is a schematic view of a glass electric kettle of the present invention;

2 is a schematic view of the glass electric kettle of the present invention not including a control portion;

Figure 3-6 is a flow chart of different working procedures of the present invention. Implementation

As shown in Figs. 1 and 2, the glass electric kettle of the present invention comprises a glass kettle 1, a heating portion and a control base 3. The heating portion includes a resistive film 2 and an electrode 5 applied to the outer surface of the bottom of the glass kettle 1. The control panel 4 on the control base 3 has a plurality of control input keys for the user to input commands, and a microcomputer processor (not shown) is mounted inside the control base 3. The water temperature sensor 7 is provided on the outer surface of the glass kettle 1 where the resistive film 2 is not applied, and is used to detect the water temperature in the glass kettle 1.

The resistive film 2 of the present invention can be applied to the bottom outer surface of the jug 1 using a composition or production process well known in the art.

The present invention also provides a dry burn temperature sensor 6 on the area where the resistive film 2 is applied to the outer surface of the bottom surface of the glass kettle 1. When dry burning occurs, the microcomputer can react in time to turn off the power and issue a warning signal.

The microcomputer processor of the glass electric kettle of the invention is pre-installed with a control program, and the basic working procedures include active dry burning detection, boiling heating, ordinary heating, and active dynamic constant temperature. Figure 3-6 is a flow chart of the above working procedure. As shown in Figure 3, the active dry burn test is performed before each heating operation. First, the resistive film is heated with 180-220W as the test standard power, and the temperature rise measured by the dry burn sensor 6 is measured within 28 seconds. The value ΔΤ is compared with the theoretical expected temperature rise value ΔΤ d. If ΔΤ has reached ATd within 28 seconds, it is determined that dry burning has occurred; otherwise, the condition is normal, and other corresponding working procedures are performed according to the user's instruction. ATd is determined as follows:

ΔΓί = 0.8291* (1.195Γο- 15.25 + ^1) + 13.289 -Γο

, To is the initial water temperature, A is the dry burning determination adjustment constant, and the correspondence between To and Α is as follows:

Figure 4 shows the workflow for boiling heating. When the user inputs the "boil heating" command, the microcomputer processor first performs the active dry burn detection as described above. If the test result is normal, the resistive film 2 continues to heat, and when the water temperature sensor 7 measures the water temperature relative to the boiling. At a lower temperature, such as 90 ° C, the time interval T4 required to raise the temperature by 4 ° C is measured, and then it is measured whether the rise in water temperature exceeds 0.5 ° C in each T4 time interval. If it is exceeded, the heating is continued. If it is not exceeded, it indicates that the water temperature has reached boiling point. The microcomputer processor issues a boiling prompt.

Figure 5 shows the workflow for normal heating. The "normal heating" is only a case of "boiling heating" as described above, and means that the heating temperature set by the user is lower than the boiling point. In the process of "normal heating, in order to prevent the water temperature from rising rapidly to the set temperature, the microcomputer processor's control program sets a heating buffer when the water temperature approaches the set temperature, with a lower heating power. Heating (e.g., 325W) causes the water temperature to gradually ramp to the temperature set by the user. In a preferred embodiment of the invention, the starting temperature Ts of the heating buffer is calculated as follows:

# 7 (Ζ„ + ΔΖ)

Where Ζ ₀ is the buffer temperature calculation constant, ΔΖ is the compensation coefficient, Ζ ₀ , ΔΖ are as follows: • ΔΖ = -\u(T - Γ ₀ ) ⁴ +100Μ(Γ -Τ ₀ Ϋ - 500w( f -Γ ₀ ) ² -0.1762(Γ -T ₀ ) + 0.2658

9 Ζ„ = 1.02Γ- 4.781

In the above calculation formula, Τ is the set temperature input by the user, and To is the initial water temperature. u is 10 ^-6 .

When the user enters the set heating temperature T, the microcomputer processor starts the "normal heating" work procedure. First, at the beginning, the starting temperature Ts of the heating buffer is calculated based on the initial water temperature To and the set temperature T measured by the water temperature sensor 7. If the measured real-time water temperature Tc < Ts, first perform "active dry burning detection", if the situation is not normal, then power off and give a prompt, otherwise the resistive film 2 is energized and heated, and the heating power is not limited at this time. Maximum rated power. Until the measured real-time water temperature Tc ≥ Ts, it indicates that the heating needs to enter the buffer zone. First, the “active dry burning detection” is performed. If the condition is normal, the heating power of the buffer is continued at 325W until the set temperature is reached.

Usually after "boiling heating" and "normal heating", the user wants to keep the water temperature at a suitable drinking temperature. In this case, the electric kettle of the present invention has an "active dynamic constant temperature" working procedure. Fig. 6 shows the working flow of the "active dynamic constant temperature" of the electric kettle of the present invention. The electric kettle of the present invention draws an active dynamic constant temperature program, that is, the temperature of the water is dynamically maintained within the temperature range of T _k +Y and T _k -X according to the temperature T _k required by the user to maintain the constant temperature. Among them, Υ, Υ can take values between 1 and 2.5 as needed. The water temperature is regarded as a constant temperature in the above temperature range. When the water temperature is above T _k +Y, it is regarded as a cooling state. When the water temperature is below T, -X, it is regarded as a heated state. In the present invention, after the water temperature enters the constant temperature state, the microcomputer processor first calculates a starting constant temperature power, and then performs active dry burning detection. If no dry burning occurs, the initial constant temperature power is used for constant temperature heating to enter. In the active dynamic constant temperature process, the microcomputer processor calculates the dynamic constant temperature power at any time according to the temperature measured by the water temperature sensor 7, and performs an update every 2-10 seconds, thereby realizing an active constant temperature process. The above initial constant temperature power P _Tk and dynamic constant temperature power P _Tk are calculated as follows:

, T _K + Y

, T _K —X

Where T _k is the constant temperature set by the user, Tc is the water temperature measured in real time, and Tp is the water temperature measured the previous time, u is 10" ⁶ and m is 10 ^-3 .

With the above active dynamic thermostat program, the water temperature can be slowly heated to the temperature set by the user and maintained for a long time. However, when encountering some sudden changes, such as adding cold water or hot water, the constant temperature state will be quickly pushed to the cooled state or the heated state. In the cooling state, the heating power is 0, that is, the resistive film does not heat up until The water temperature is cooled to a constant temperature. In the heated state, the microcomputer processor first performs active dry burning judgment, and then heats the water temperature to a constant temperature state by a normal heating working procedure. During the dynamic constant temperature process, the water temperature is heated and slowly enters the cooling state. At this low power, it enters the cooling state, which is generally not harmful to the glass kettle. However, in the case of long-term heat preservation, since the water in the kettle becomes small due to use or evaporation, dry burning may occur. At this time, the microcomputer processor executes the "constant temperature dry burning determination" program, that is, detects the number of times of the constant temperature state and the cooling state transition in the predetermined time. When the number of conversions exceeds the predetermined value, it is determined that the dry burning occurs, and the prompt signal is issued in time. Power off. According to the test, the predetermined number of conversions is related to the constant temperature set by the user, and the corresponding relationship is as follows:

On the basis of the above basic working procedures alone or in combination, the electric kettle of the present invention can be, for example, heated to boiling; kept at a set temperature after boiling; heated and maintained to a set temperature; heated to a first set temperature and The second set temperature is constant temperature and other functions.

To further prevent overheating of the heating element, the maximum temperature limit can be set to avoid damage to the glass kettle. When the dry burn sensor detects the highest temperature, the microcomputer processor signals and powers down. The maximum power and maximum temperature limits for the heating element are as follows:

While the present invention has been described with respect to the preferred embodiments, the present invention is not limited thereto, and various modifications and changes can be made to the present invention without departing from the spirit and scope of the invention.

Claims

Rights request

A glass electric kettle comprising a glass kettle, a resistive film heating portion applied to an outer surface of a bottom surface of the glass bottle, and a control portion electrically connected to the resistive film, wherein the control portion comprises a microcomputer processing preloaded with a control program a control panel having a control input button and a user inputting a work command and a set temperature, a water temperature sensor disposed on an area where the outer surface of the glass faucet is not provided with a resistive film, and a temperature sensed by the water temperature sensor is transmitted to The microcomputer processor, the microcomputer processor sends a control signal according to the input work command and the set temperature.

2. The glass electric kettle according to claim 1, wherein a dry burning temperature sensor is disposed on a region where a resistive film is applied to an outer surface of the bottom surface of the glass kettle, and when the dry burning occurs, the monitoring signal is transmitted to the computer processor. The microcomputer processor issues a control signal to turn off the power.

3. The glass electric kettle according to claim 2, further comprising a dry burn warning display device.

4. The glass electric kettle according to claim 2, wherein the basic working procedure of the glass electric water kettle comprises active dry burning detection, boiling heating, normal heating, and active dynamic constant temperature.

5. The glass electric kettle according to claim 4, wherein the active dry burning detection is performed as follows: First, the resistive film is heated with a test standard power of 180-220 W, and the temperature measured by the dry-burning sensor is measured within 28 seconds. The rising value ΔΤ is compared with the theoretical expected temperature rise value ΔΤ d. If ΔΤ has reached ΔΤ d within 28 seconds, it is determined that dry burning occurs; otherwise, the situation is normal, and other corresponding working procedures are performed according to the user's instruction. , ΔΤ d is determined as follows:

ATci = 0.8291 * (1.195Γο - 15.25 + A) + 13.289 - To

Where, To is the initial water temperature, A is the dry burning determination adjustment constant, and the correspondence between To and Α is as follows: Initial temperature To A

<o°c 70

0. C≤To<30°C 73

30°C<To<50°C 79

50°C≤To<70°C 83

70°C<To<90°C 80

90°C≤To<105 °C 74

The glass electric kettle according to claim 4 or 5, wherein the active dry burning test is performed before each heating operation.

7. The glass electric kettle according to claim 4, wherein in the boiling heating working procedure, when the water temperature measured by the water temperature sensor is lower than 90 ° C, the time interval T4 required for heating up 4 ° C is measured. Then, measure whether the rise of water temperature exceeds 0, 5 °C in each T4 time interval. If it exceeds, continue heating. If it is not exceeded, it indicates that the water temperature reaches boiling point.

8. The glass electric kettle according to claim 4, wherein in the normal heating operation, the control routine of the microcomputer processor sets a heating buffer when the water temperature approaches the set temperature, so as to be lower. The heating power is heated to gradually increase the water temperature to a temperature set by the user, wherein the starting temperature Ts of the heating buffer is calculated as follows:

7 (Ζ„+ ΔΖ)

Where Ζο is the buffer temperature calculation constant, ΔΖ is the compensation coefficient, Ζ ₀ and ΔΖ are as follows: ® ΑΖ =

In the above calculation formula, Τ is the set temperature input by the user, and To is the initial water temperature, u is 10 ^-6 .

9. The glass electric kettle according to claim 8, wherein the lower heating power after entering the heating buffer is 325 W.

10. The glass of the electric kettle as claimed in claim 4, wherein, in the working program active dynamic temperature of the electric kettle according to a user desired to maintain constant the input temperature T _k, will dynamically hold water In the temperature range of T _k +Y and T _k -X, where Χ and Υ are between 1-2.5, the water temperature is regarded as a constant temperature in the above temperature range, when the water temperature is above T _k +Y In the cooling state, when the water temperature is below T, -X, it is regarded as a heating state. When the water temperature enters the constant temperature state, the microcomputer processor first calculates a starting constant temperature power, and starts the constant temperature power to perform the heat preservation and heating to enter the dynamic constant temperature process. The processor calculates the dynamic constant temperature power at any time according to the temperature measured by the water temperature sensor, and updates every 2-10 seconds to realize a dynamic constant temperature process. The initial constant temperature power P _Tk and the dynamic constant temperature power P _Tk are calculated as follows:

_ 30"Γ + ΊΑηιΤ _κ —0.659 + 25.1Γ _Α , - 340 , Τ _Κ + Υ

― 75"7 .― 16.6/7/ ³ + 1.587; ² - 64.07; + 945 , Γ, one X

Where T _k is the constant temperature set by the user, Tc is the water temperature measured in real time, and Tp is the water temperature measured the previous time, u is 10' ⁶ and m is 10 - ³ .

1 . The glass electric kettle according to claim 10, wherein during the active dynamic constant temperature operation, the microcomputer processor further executes a “constant temperature dry burning determination” program to detect the constant temperature state and cooling in 5 minutes. When the number of state transitions exceeds the predetermined number of transitions, it is determined that dry burn occurs, a prompt signal is issued and the power is turned off, and the predetermined number of transitions is associated with the constant temperature set by the user, and the correspondence is as follows:

User requires constant temperature T _k conversion times (within 5 minutes)

20 ° C <T _k <40 ° C 2

40 ° C < T _k <60 ° C 3

60 ° C < T _k <80 ° C 5

80°C<T _k <90°C 7