JPH11149973A - Heating device using heater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase convenience in use by preventing the loss of function of a heater even if part of wire is broken, and diversify the power control of the heater. SOLUTION: Both ends of a plurality of heater wires 2 are connected to common electrodes 3, 3 to constitute a heater 1, the heater 1 is connected to a power source 16 and a microcomputer 17 through a switching circuit 15, the switching circuit 5 is switched to the power source 16 side to supply electricity to the heater 1, and switched to the microcomputer 17 side in the adequate time to measure the combined resistance of the heater 1, combined resistance in a normal state is compared with the combined resistance in a wire broken state to detect the occurrence of the breaking of wire.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heating device such as a water heater using a heater.

[0002]

2. Description of the Related Art A conventional thin heater used in a heating device such as a water heater is a device in which one or two heater wires having a length of about 2 m are wound around an insulating plate such as a mica plate. It is sandwiched between two insulating plates and further sandwiched by a casing such as an aluminum plate for use.

[0003]

As described above, the conventional heater has a disadvantage that if one of the heater wires is disconnected, all the heater wires lose their functions. Also,
Because it consisted of one or two heater wires,
There is a problem in that the mode of power control of the heater is limited, and various power controls cannot be performed.

Accordingly, an object of the present invention is to increase the convenience of use and to diversify the power control of the heater by preventing the function of the heater from being lost even if there is a partial disconnection.

[0005]

In order to solve the above-mentioned problems, according to the present invention, both ends of a plurality of heater wires are respectively connected to a common electrode, and a switching circuit is provided between the common electrode and a power supply. A control circuit comprising a switching control means for the switching circuit and a comparison detection means for detecting the presence or absence of a disconnection by comparing the combined resistance of all heater wires in a normal state and the combined resistance when one or more heater wires are disconnected. It was provided with a configuration (claim 1).

According to the above configuration, when one or a plurality of heater wires are disconnected, it is possible to take measures such as notification while continuing to supply current to other normal heater wires.

Further, in order to solve the above-mentioned problem, the present invention connects each one end of a plurality of heater wires to one common electrode, and combines one or more of the other ends of the heater wires to form a plurality of heater wires. A control switch is connected between the control electrode and each of the control electrodes and the power supply circuit, and a control circuit including control means for the control switch is provided.

[0008] According to the above configuration, the number of heater wires to be energized changes according to the turning on and off of the control switch by the control circuit, so that various power controls can be performed.

[0009]

Embodiments of the present invention will be described below with reference to the accompanying drawings. The first embodiment shown in FIGS. 1 to 5 relates to a pot heater and a heater control circuit. The heater 1 is, as shown in FIGS.
A required number of heater wires 2 composed of heat-generating resistors are arranged in parallel in a required number, and both ends thereof are connected to common electrodes 3, 3, respectively, and each common electrode 3 is provided with a lead terminal 4.

As one means for connecting the heater wire 2 to each common electrode 3 in parallel, in this embodiment, as shown in FIG. 2, one heater wire 2 is zigzag with a constant swing width. And a folded portion 5 parallel to the common electrode 3 and a right-angled heating portion 6 are formed, and the heating portions 6 are arranged at a constant pitch in the length direction of the common electrode 3. .

As shown in FIGS. 3 (a) and 3 (b), the common electrode 3 is formed by bending a strip-shaped conductor plate into a U-shape so that the upper plate 7 and the lower plate 8 face each other. A notch 9 is provided in the upper plate 7 at a position corresponding to the notch portion 5, and a holding piece 11 corresponding to the notch 9 is provided in the lower plate 8. The width A (see FIG. 3A) of the notch 9 and the holding piece 11 is formed to be equal to or slightly smaller than the width B inside the folded portion 5.

The folded portion 5 is placed on the holding piece 11 and the holding piece 11 is bent toward the notch 9 through the inside of the folded portion 5 (see the dashed line in FIG. 3A). ), The folded portion 5 is swaged by the holding piece 11 to fix the heater wire 1 to the common electrode 3.

FIGS. 3C and 3D show another structure for fixing the heater wire 1 to the common electrode 3. In this case, the common electrode 3 is formed of a single strip-shaped conductor plate, and is provided with a pair of opposing cut-and-raised pieces 12 having a length that enters the inside of the folded portion 5.

The folded portion 5 is formed by a pair of cut and raised pieces 12.
After that, it is bent inward and caulked (see FIG. 3D), and the common electrode 3 and the heater wire 1 are integrated.

As described above, the heater 1 having a structure in which a large number of heat generating parts 6 are connected in parallel between two parallel common electrodes 3 is formed. The heater 1 is sandwiched between insulating plates 13 and 13 such as a mica plate and, if necessary, between cover plates such as aluminum.

FIG. 4 shows a heater control circuit for a pot using the above-described heater 1. The heater 1 is connected to a power supply 16 and a microcomputer 17 via a switching circuit 15. Switching circuit 1
Reference numeral 5 denotes a movable contact 15a of the switching relay 14, a first fixed contact 15b, and a second fixed contact 15c. The movable contact 15a is connected to the heater 1, and the first fixed contact 15b
Is a power supply 16 and the second fixed contact 15c is a microcomputer 17
Connected to each other. When the switching relay 14 is not energized, the movable contact 15a contacts the second fixed contact 15c as shown by a two-dot chain line.

The power supply of the control circuit 18 is a DC power supply obtained by rectifying the power supply 16 with a resistor R ₁ and a diode D, smoothing it with a capacitor C, and making the voltage constant with a zener diode Z.

The second fixed contact 15 of the switching circuit 15
c is through a resistor R ₂ is connected to the DC power source, has a voltage drop across the resistance R ₂ to be inputted to the microcomputer 17.

The winding 19 of the switching relay 14 and the transistor switch 21 are switched between the DC power supply and the ground.
There are connected in series, the input terminal of the transistor switch 21 is connected to the microcomputer 17 via the resistor R _3.

Reference numeral 22 denotes a thermistor for taking in the water temperature, 23 denotes a light emitting diode for displaying a warning, and 24 denotes a light emitting diode for displaying a disconnection.

The pot of the first embodiment is as described above, and the control for detecting disconnection of the heater 1 by the microcomputer 17 will be described with reference to the flowchart of FIG.

The resistance value of each heater wire 2 of the heater 1 is 100Ω, and if ten wires are connected in parallel, the composite resistance value R _{0 in} normal operation is 10Ω, and the heater wire 2
The combined resistance value R ₀ when one of them is disconnected is 11.1Ω, and the combined resistance value R ₀ when one is disconnected is 12.5Ω.

[0023] When the process flow starts, the magnitude of the voltage drop across the resistor R ₂ and measuring the combined resistance value R ₀ of the heater 1 in ipecac in the microcomputer 17 (step 1). As a result of the measurement, when the resistance value R ₀ is smaller than 11.1Ω,
Judge as normal (step 2), transistor switch 2
1 is turned on to excite the winding 19 of the switching relay 14,
The movable contact 15a is switched to the first fixed contact 15b to energize the heater 1 (step 3). Thereafter, the normal water heating flow is executed (step 4), and the flow is terminated.

[0024] In Step 2 above, when the resistance value R ₀ is greater than 11.1 because the heater line 2 is that the broken least one further resistance R ₀ in the next step 5 is 12 It is determined whether the value is larger or smaller than 0.5Ω. If the value is smaller than 1.5Ω, only one disconnection is made. Therefore, only a warning is displayed (step 6), and the process proceeds to the next steps 3 and 4. However, when the resistance value R ₀ is larger than 12.5Ω, the disconnection is 2
Since the number is equal to or more than the number of wires, a disconnection display is performed (step 7), the power supply to the heater 1 is cut off (step 8), and the flow ends.

FIG. 6 is a flowchart of another control method.
Is turned on to energize the switching relay 14 and its winding 19
And the movable contact 15a is switched to the first fixed contact 15b to energize the heater 1. Next, the temperature of the kettle is taken from the thermistor 22 (step 2), and it is detected whether or not boiling has been reached (step 3). If the boiling has not been reached, after a certain period of time (for example, 10 minutes) has elapsed (step 4), the transistor switch 21 is turned off, the excitation of the winding 19 is cut off, and the movable contact 15a is returned to the second fixed contact 15c. Then, the power supply to the heater 1 is turned off, and the resistance value R ₀ of the heater 1 at that time is measured (step 5). As a result, the resistance R ₀ becomes 11.1Ω.
If smaller (step 6), continue with heater 1
Is supplied (step 1), and the same flow is repeated thereafter.

In step 6, the resistance value R ₀ is 11.1
If it is not less than Ω, it is further determined whether or not it is not less than 12.5 Ω (step 7). If it is less than 12.5 Ω, the warning display light emitting diode 23 is turned on to display a warning (step 8). Power is supplied to the heater 1 (step 1), and the same flow is repeated thereafter. When it is 12.5 Ω or more, the disconnection display light emitting diode 24 is turned on to display the disconnection (step 9), the heater is turned off (step 10), and the flow is terminated.

When it is detected in step 3 that boiling has occurred, the power supply to the heater 1 is turned off (step 11), and the flow ends.

Next, a second embodiment will be described with reference to FIGS. In this case, the heater wire 2 has one end of each of the seven heating sections 6 connected to one common electrode 3 and the other end connected to a common electrode 4.
Control electrode 25
a, 25b, and 25c. The method of connecting the heater wire 2 to the common electrode 3 and the control electrodes 25a, 25b, 25c is the same as in the case of the first embodiment.

FIG. 8 shows a control circuit, in which the heater 1 connects the common electrode 3 to a power source, and controls the control electrodes 25a, 25a.
a first control contact 26a, a second control contact 26b, and a third control contact 2 as control switches on the sides b and 25c, respectively.
6c is connected to the ground. Each contact 26 described above
a, 26b, 26c first to third relay windings 27
a, 27b and 27c are connected between the DC power supply and the ground via transistor switches 28a, 28b and 28c, respectively.

In this case, when all or any of the transistor switches 28a, 28b, 28c are turned on by a signal from the microcomputer 17, the windings 27 of the first to third control relays 29a, 29b, 29c corresponding to these are turned on.
a, 27b, and 27c are excited, and all or any of the first to third control contacts 26a, 26b, and 26c are turned on, and the heater wire 1 is energized.

Table 1 shows the combinations of the contacts 26a, 26b, and 26c that are turned on, the combined resistance R ₀ , the power at a power supply of 100 V, and examples of use at that time. NO. 3 and NO. The slow boiling water of 4,
It is suitable for removing calcium by heating for a relatively long time until boiling, such as night sleep time.

[0032]

[Table 1]

[0033]

As described above, according to the present invention, the heater wires are connected in parallel to the common electrode, so that even if one or more wires are broken, the current supply to the remaining heater wires is continued. In addition to this, a required display or notification can be performed to notify the disconnection (claim 1).

Further, by dividing a plurality of heater wires into a plurality of sets and supplying power through the control switches, various combinations of power can be generated, and various heating controls can be performed. (Claim 2).

[Brief description of the drawings]

FIG. 1 is a perspective view of a heater according to a first embodiment.

FIG. 2 is a plan view of the above.

3 (a) is a partially exploded perspective view of the same, (b) is a partial cross-sectional view of the same, and (c) is an exploded perspective view of a modification of the same.

FIG. 4 is a control circuit diagram of the above.

FIG. 5 is a flowchart of the above.

FIG. 6 is another flowchart of the above.

FIG. 7 is a plan view of a heater according to a second embodiment.

FIG. 8 is a control circuit diagram of the above.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Heater 2 Heater wire 3 Common electrode 4 Lead terminal 5 Folding part 6 Heating part 7 Upper plate 8 Lower plate 9 Notch 11 Pressing piece 12 Cut and raised piece 13 Insulating plate 14 Switching relay 15 Switching circuit 16 Power supply 17 Microcomputer 18 Control circuit 19 Winding 21 Transistor switch 22 Thermistor 23 Light emitting diode for warning display 24 Light emitting diode for disconnection display 25a-c Control electrode 26a First control contact 26b Second control contact 26c Third control contact 27a-c Winding 28a- c Transistor switch 29a First control relay 29b Second control relay 29c Third control relay

Claims (2)

[Claims] 1. A switching circuit is provided between the common electrode and a power supply, and both ends of a plurality of heater wires are connected to a common electrode, and a switching control means of the switching circuit and a combined resistance of all heater wires in a normal state are provided. And a heating device using a heater provided with a control circuit provided with a comparison detecting means for detecting the presence or absence of disconnection by comparing the combined resistance when one or more heater wires are disconnected. 2. One end of each of the plurality of heater wires is connected to one common electrode, and one or more of the other ends of the heater wires are connected to a plurality of control electrodes in combination. A heating device using a heater, wherein a control switch is connected between the control switches and a control circuit including control means for the control switch is provided.