JPS5956630A - Boiling detecting device - Google Patents

Abstract

PURPOSE:To enable contineously the highly accurate boiling detection irrespective of the quantity of thermal integrity by a method wherein a temperature detector output which s varied according to the quality of thermal integrity between a vessel and a temperature detector is adequately processed, when a water containing vessel is heated by a heat generating body. CONSTITUTION:At the closing of a start switch 12, a three terminal double- throw thyristor 9 is turned ON by a microcomputer 11 via a transistor 13, a heat generating body is heated, a vessel 7 is also heated. Thereby, a water inside of the vessel 7 is boiled at A point, at this time, when the quality of thermal integrity between a vessel 7 and a thermistor 10 is adequate, the temperature of the thermistor 10 is stabilized at the temperature higher 10-15 degree than the boiling point, on the other hand, when the quality of thermal integrity is inadequate, the rate of temperature rising becomes smaller at the designated temperature B higher than the temperature at A point. Therefore, the microcomputer 11 judges the boiling of the water in case that the temperature of the thermistor 10 is lower than the designated temperature and the rate of temperature rising is lower than the designated rate, then lights a luminous diode 15, the electrifying is stopped.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a device for detecting boiling of water in a container in a thermal appliance such as an electric stove.

Conventional configuration and its problems Conventionally, in the case of a boiling detection device that detects the temperature of the container using a thermostat and stops energizing the heater when the temperature exceeds a predetermined temperature, the thermostat prevents malfunctions due to radiant heat received from the heater. The boiling detection point is set at 90'C to prevent malfunctions due to differences in boiling point due to atmospheric pressure, etc.
The temperature had to be kept at about 95'C. That is 100'
It was not possible to detect the completion of boiling at C (at normal pressure).Purpose of the Invention In order to solve the above problem, the present invention continuously measures the temperature rise rate of a temperature detector that detects the temperature of the container. However, if the thermal coupling between the container and the temperature sensor is good, when the temperature rise rate of the temperature sensor falls below a predetermined value, conversely, due to dirt etc. adhering between the temperature sensor and the temperature sensor, If the thermal coupling is poor, a boiling state is detected when the temperature detector reaches a predetermined value of 6 m degrees μ.

The configuration of the boiling detection device of the present invention is as follows: A heating element for heating a container containing water is provided, a temperature sensor is provided which is thermally coupled to the container, and the temperature sensor was detected 17i!i
A vorticity upper H rate measuring means uses i'1 degree as an input signal to measure the temperature of the crystallinity detector; Detector is specified 717
If the thermal coupling between the container and the temperature sensing element is good, the output of the temperature fluctuation ξ measuring means is used to determine whether the thermal coupling between the container and the temperature sensing element is good. On the other hand, if the thermal coupling is poor, boiling determination means determines that the water in the container has boiled based on the output of the temperature determining means, and J is determined by the output of the boiling determination means. : Notifies that the water in the container being moved is boiling/column.
It consists of a JB rising notification means and a heating element energization control means for controlling energization to the heating element.

In the configuration of the present invention, even if the temperature sensor is located near the heating element, if the thermal coupling between the temperature sensor and the container is good, the crystallinity difference between the container and the single-grade detector is small. Therefore, when the water in the container rises by 7 Vlli, the temperature of the temperature sensor also tries to stabilize at a temperature slightly above the boiling point of water, so the temperature upper limit ratio of this temperature sensor falls below the predetermined value. A boiling state can be detected at this point. Therefore, the power supply to the heating element is stopped, for example, and the user is notified that the dli has risen by means such as a sounding body light emitting element.

Next, if the thermal coupling between the temperature sensor and the container is poor, even if the water in the container rises θ1), the temperature of the temperature sensor will rise at a constant rate of increase due to the influence of the heating element. Therefore, in this case, boiling can be detected only after boiling has elapsed for a certain period of time after boiling. Therefore, in this case, if the temperature detector determines that the boiling state has occurred when the temperature reaches -1- below a predetermined temperature, it is possible to detect the boiling state with better accuracy.

DESCRIPTION OF EMBODIMENTS An electric stove as an embodiment of the present invention will be described below. In the figure, 1 is an AC power supply, one chip 2,
]J (Resistor 3, Zener diode 4, resistor 6, and diode 6 form a DC power supply for operating the control circuit.7
is a container containing water, 8-5 is a heating element, and 9 is an E-terminal bidirectional thyristor which is a heating element energization control means.

When the three-terminal bidirectional thyristor 9 is turned on, the heating element 8 generates heat, and the container 7 can be heated. 10 is 1
; It is a thermistor which is an integrity detector, and is thermally coupled to the container 7 and installed near the heating element. In the case of electric stoves, etc., the heating element is a spiral-shaped heater, and a thermistor is protruded from the bottom of the central part of the heater to detect the temperature of the container, so there is no dirt between the container and the temperature sensor. The temperature sensor is affected by the heating element, such as when the temperature sensor is harvested. The same thing can be said even if the temperature sensor is installed on the side of the container.

The control device is made up of a micro combi coater 11 and a circuit on the same side. Microcombi shown here, z, -Qi
It is a so-called one-chip microcomputer consisting of a CPU, a ROM, a RhM, and an input/output board.

When the start switch 12 is closed, the boiling detection operation is started, and the micro combi coater 11 detects the transistor 13.
, the heating element energization control means 9 is energized, and the heating element 8 is energized.
Electrify. Therefore, the container 7 is heated and the temperature sensor 1
The temperature of the water in the container rises to - due to the influence of the container 7 and the heating element 8. i?li
The relationship between 'L degrees and the temperature of the thermistor 10 is shown in Figure 2.3 In Figure 2, A indicates the water temperature in the container7.
, 口 indicates the temperature of the temperature sensor in the case of good thermal coupling, and C indicates the temperature of the temperature sensor in the case of poor thermal coupling.

Assuming that the water temperature in the container boils at point A, 1QO'C
Suppose that it reaches a stable state. If the thermal coupling is good, the temperature of the temperature sensor 10 will try to stabilize at 1Q~15deg higher than the rising point of υ18, so ? It is possible to detect a boiling state by a decrease in the rate of increase in blackness. - If the thermal connection is still poor due to dirt, etc., even though the water in the container has boiled, the temperature of the temperature detector will continue to rise even after A, and at this temperature the Jjr rate d: Although it is smaller than that before point A, the water in Figure 2:); In the case of a larger amount of water, d: The temperature before point A is 10E・ne (or smaller, so the means for determining that the rate of increase is below a certain temperature) is Accurate detection is impossible. Therefore (at 411 shown in Fig. 2), the altitude detector is located at (
So (best): c! -C boiling 1 with 1 degree B/ζ time
If all five states are detected in 1, the viscosity can be detected with good accuracy.

? 7rX, the temperature of the degree detector 10 is sent to the micro combicoter 11 via the A/D converter 14. The boiling detection operation is completed based on this temperature take.
Then, the microcombi 11 turns on the light-emitting diodes 1-15, which are the JB rising status display devices, turns off the transistor 13, and turns off the communication to the heating element 8.
1 so that I'iI/forms.

Next, the operation of the boiling detection device constructed as described in the notes will be explained.

Pour water into the container 7, press the start switch 12, and press the start switch 12.
Boiling detection is started based on the program procedure shown in the flowchart in the figure.

First, in step (2), the heating element 8 is energized to heat the container, and in step (2), it is determined whether the temperature of the crystallinity detector 10 is above a predetermined temperature, and if it has not reached that temperature, In step (2), the rate of temperature increase is measured, and in step (2), it is compared to see if it is less than or equal to a predetermined temperature H rate, and if the temperature is higher than that, the process returns to step (2) and the rate of temperature increase is continuously measured. If the temperature rise rate falls below the predetermined rate in step ■,
If the temperature is higher than the predetermined temperature, it is determined that the boiling has occurred in step (2), the light emitting diode 15 as a boiling completion notification means is turned on in step (2), and the power to the heating element 8 is stopped in step (2). Complete the detection operation.

As explained above, boiling can be detected with high accuracy.Achievements of the InventionAs is clear from the above explanation, according to the present invention, even when the thermal coupling between the container and the temperature sensor is good, dirt, etc. can be detected. ;) Even if the temperature is low, it is possible to detect the temperature with high accuracy.

[Brief explanation of the drawing]

Fig. 1 shows an electric circuit of a boiling detection device showing an embodiment of the present invention, Fig. 2 shows a temperature characteristic diagram of the main parts of the same, and Fig. 3 shows the same / Fig. 3.
! It is a flowchart showing an example of a blog of a lli l direction detection device. 7... Container, 8... Heating element, 9... Heating element; Streetcar control means, 10... Temperature detector, 11... Micro-1 ambiator, 150. Boil, alarm means. Name of agent: Patent attorney Toshio Nakao and 1 other person 2nd
Illustrated poem open □ Figure 3

Claims (1)

[Claims] A heating element that heats a container that collects water, a temperature detector that detects the temperature of the container, and an E rate over temperature of the temperature detector that uses the temperature detected by the temperature detector as an input signal. A temperature rise rate measuring means, a temperature determining means that uses the temperature detected by the temperature detector as an input signal to determine that the seat temperature is higher than a predetermined temperature, and an output of the temperature determining means and the temperature. 5jl Using the output of the rate determining means as an input signal, it is determined that the water in the container has boiled when the temperature of the temperature detector reaches a predetermined temperature range and reaches a predetermined temperature increase rate. 7JB boiling determination means to perform boiling j14!, boiling notification means for notifying nl) boiling completion based on the output of the boiling determination means, and boiling j14! A boiling detection device comprising heating element energization control means for controlling energization of the heating element based on the output of the notification means.