JPH0632262B2 - Control device for electric hot plate - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to an electric hot plate for general household use.

2. Description of the Related Art As shown in FIGS. 4A and 4B, a conventional hot plate detects the temperature of the plate 4 by a temperature detecting means 2 such as a bimetal thermostat connected in series to an AC power source 1 and mechanically contacts the contacts. It is configured to open and close to control the temperature of the metal plate 4 in which the heater 3 is embedded.

Problems to be Solved by the Invention However, in the above-mentioned configuration, the contacts of the bimetal thermo are easily welded, and when these mechanical failures occur, if the power is connected and the switch is turned on and left, it has a drawback that it continues to operate forever. Was there. Therefore, the high temperature condition persists, and there is a risk of accidental burns or a fire in the worst case. It also has a drawback that it consumes wasteful power forever.

In view of the above-mentioned drawbacks, the present invention provides a control device for an electric hot plate, which aims to prevent the risk of burns, fires, etc. because the high temperature state does not continue even if the user forgets to turn off the switch and is left. Is.

Means for Solving the Problems In order to achieve this object, an electric hot plate controller according to the present invention comprises a temperature detecting means for detecting the temperature of the plate and a temperature controlling means for controlling the temperature at a plurality of temperature points. , A control temperature setting means having a control temperature setting switch for setting the control temperature, and a time measurement for starting the time counting from the time when the control operation of the temperature control means is started and resetting the time counting each time the control temperature setting switch is pressed. Means, a timekeeping prohibiting means for prohibiting the timekeeping operation, and a control operation stopping means for stopping the control operation in the temperature control means.When the control temperature is the lowest, the timekeeping is prohibited, and at other control temperatures. The operation is stopped after a certain period of time.

Operation With this configuration, the control temperature setting switch is pressed, the temperature control means adjusts the plate temperature to a constant temperature based on the information from the temperature detection means, and at the same time, the time measurement means starts the time measurement and the control temperature Each time the setting switch is pressed, the clock time is reset and the clock starts. Here, when the control temperature is the minimum control temperature by the time counting prohibiting means, the time counting operation of the time counting means is stopped. When the time measured by the time measuring means is measured for a certain period of time or longer, that is, when no switch is pressed for a certain period of time, the control operation of the temperature control means is stopped by the control operation stopping means to stop the energization of the heater. This makes it possible to prevent the plate temperature from being maintained at a high temperature in a dangerous state.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention.
Reference numeral 1 is an AC power source, 3 is a heater, 5 is a relay for connecting and disconnecting electricity to the heater 3, and is composed of a contact point 5a and a coil 5b. 5b is controlled by the temperature control means 7. The temperature control means 7 is adapted to perform a control operation based on a signal from the temperature detection means 6 which detects the temperature of a plate formed of a negative characteristic thermistor or the like. Further, the temperature control means 7 has a start switch 8 that starts when pressed once and stops when pressed again, a signal from the control temperature setting means 9 that sets the control temperature of the temperature control means 7, and a signal from the control operation stop means 12. I am trying to give.
The control temperature setting means 9 sets the temperature of the plate to the optimum temperature for cooking during use, and operates when the control temperature setting switch 10 is pressed. As shown in FIG. 2, the temperature of the plate is θ ₁ (80 ° C.), θ
₂ (180 ° C) and θ ₃ (230 ° C) can be set to three types of control temperature. Every time the control temperature setting switch 10 is pressed, the set temperature is θ ₁ → θ ₂ → θ ₃ → θ _1. Is changed. When pressed, if the set temperature is θ ₁ , θ
To _2, it is changed to a temperature raised to theta ₃ if theta _2, so that the set temperature is returned to the theta ₁ if theta _3.

Reference numeral 11 is a time counting means for starting time counting from the time when the start switch 8 is pressed, and is adapted to give a time counting signal to the control operation stopping means 12. Reference numeral 13 denotes a time counting prohibiting means for stopping the time counting operation of the time counting means 7 when the control temperature θ _S in the temperature control means 7 is the minimum control temperature θ ₁ (80 ° C.).

The constructed control apparatus for an electric hot plate as described above, following the operation control temperature theta _S of FIG. 2 theta ₃
A temperature characteristic diagram showing the temperature change of the plate when set to 1 and the flow chart shown in FIG. 3 will be described. First, when the start switch 8 is pressed, the control temperature θ _S of the temperature control means is initially set to θ ₁ (80 ° C.) in step 101. In step 102, the process proceeds to the next step 103 only when the control temperature θ _S is other than θ ₁ .
In step 103, the time counting time T in the time counting means 11 is reset and the time counting is started, and in step 104, the time counting time T is counted up every 1 second. Next step 10
In step 5, if the measured time T is less than 60 minutes, step 106
The temperature detection means 6 detects the temperature θ of the plate, and the plate temperature θ is compared with the set control temperature θ _S in step 107. If θ <θ _S , step 108
In step 109, the relay 5 is turned on, and if θ ≧ θ _S , the relay 5 is turned off in step 109 to stop energizing the heater. In the next step 110, it is judged whether or not the control temperature setting step 10 has been pressed, and if not, step 10
Return to step 4, and perform the same operation thereafter. If pressed, proceed to step 111 to set the control temperature θ _S currently set.
Is not θ ₃ (230 ° C), that is, θ _S is θ ₁ (80
Control temperature if the process proceeds to step 112 in ° C.) or θ ₂ (180 ℃) is reset to a raised control temperature. For θ _S = θ ₃ in step 111 is re-set to θ _S = θ ₁ at step 113. After that, the process returns to step 102, and when θ _S is θ ₁ (80 ° C.) in step 102, that is, when it is the minimum control temperature, the process proceeds to step 106, and the operations from steps 103 to 105 are not performed, therefore θ _S =
In the case of θ ₁ , the timing of the timing means is not performed. If θ _S ≠ θ ₁ in step 102, the process proceeds to steps 103, 104, and 105, and if the time count T is 60 minutes or more in step 105, the process proceeds to step 114 to turn off the relay and stop energizing the heater. Then, the control operation of the temperature control means is also stopped. The time T is 6
If it is less than 0 minutes, the process proceeds to step 106 and the above-mentioned operation is repeated. Even if the user forgets to turn off the switch by performing the series of operations described above, if the control temperature is high, the control operation is automatically stopped and the power to the heater is stopped. It is possible to prevent a dangerous situation from occurring.

In the above embodiment, the control temperature setting means 9 changes the set temperature to a higher temperature by increasing the temperature θ ₁ → θ ₂ → θ ₃ each time the setting switch 10 is pressed, but θ ₃ → θ ₂ → It is also possible to change the temperature to a temperature one step lower than θ _{1. In} this case, the condition of step 111 may be θ _S ≠ θ ₁ and the setting of step 113 may be θ _S = θ _{3 and} the setting of step 112 at this time Becomes θ _S = θ _S-1 .

EFFECTS OF THE INVENTION As is apparent from the above description of the embodiments, the present invention is such that the temperature detection means for detecting the temperature of the plate, the temperature control means for controlling the temperature at a plurality of temperature points, and the control temperature controlled by the temperature control means. A control temperature setting means having a control temperature setting switch for setting, and a time counting means for starting time counting from the time when the control operation of the temperature control means is started and resetting the time counting each time the control temperature setting switch is pressed, By providing a time prohibiting means for prohibiting the time measuring operation of the time measuring means and a control operation stopping means for stopping the control operation of the temperature control means, the user forgets to turn off the switch and leaves it in a state where the temperature control is being performed. Even if it is done, it will automatically stop after a certain period of time, the power supply to the heater will be stopped, and it will be prevented that the user will be injured unexpectedly. It is also prevented from becoming. Furthermore, at the minimum control temperature used as a heat retention after cooking, continuous use is possible regardless of time. Also, each time the control temperature setting switch is pressed, the time measured by the time measuring means is reset and the time is re-measured, so that the control temperature can be changed with the setting switch, even if it is used continuously without stopping the temperature control. The effect is great such that it can be used without stopping the control operation.

[Brief description of drawings]

FIG. 1 is a block diagram of a control device for an electric hot plate according to an embodiment of the present invention, FIG. 2 is a plate temperature characteristic diagram, FIG. 3 is a flowchart, and FIGS. 4a and 4b are conventional electric hot plate control devices. It is a circuit diagram and a block diagram of a device. 6 ... Temperature detection means, 7 ... Temperature control means, 9 ... Control temperature setting means, 11 ... Timekeeping means, 12 ... Control operation stopping means, 13 ... Timekeeping prohibiting means.

Claims (1)

[Claims] 1. A control comprising a temperature detecting means for detecting the temperature of a plate, a temperature control means for controlling the temperature at a plurality of temperature points, and a control temperature setting switch for setting a control temperature controlled by the temperature control means. A temperature setting means, a time counting means for starting time counting from the time when the control operation of the temperature control means is started, and resetting the time counting each time the control temperature setting switch is pressed, and a time counting inhibiting means for inhibiting the time counting operation of this time counting means. And a control operation stopping means for stopping the control operation in the temperature control means, and when the control temperature set by the control temperature setting means is the minimum control temperature, the timekeeping operation by the timekeeping means by the timekeeping prohibiting means When the set control temperature is other than the minimum control temperature, the timekeeping means starts the timekeeping operation and when the time is measured for a fixed time, the temperature control means stops the energization of the heating means. Control apparatus for an electric hotplate, characterized in that.