JPS5826959A - Temperature controlling device for hot-water reserving type electric water heater - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a temperature control device for a hot water storage type electric water heater used in toilet bowls with private parts cleaning devices, etc., and is aimed at reducing radio frequency induced interference and flicker. It is.

The hot water storage capacity of a hot water storage type electric water heater used for a toilet bowl with a private cleaning device is 11/! It is designed to allow cleaning for about 1 minute at a flow rate of 1 inch, and a flow rate of about 1E is normal. On the other hand, the heater capacity is about 11 av in order to keep the waiting time for boiling within 3 minutes during continuous use in the middle of winter. The conventional temperature control device with the above configuration includes:
There was a device that controlled ON-OFF of the heater, but flickering occurred because the heater was repeatedly turned ON-OFF for one bacterium when keeping the temperature of the stored hot water. The differential was widened to suppress the 0u-OFF frequency. As a result, the control temperature fluctuated widely, making it difficult to use.

There were other devices that controlled the phase of the heater to reduce fluctuations in the controlled temperature, but since it was a 1'IM heater phase control, radio frequency induction interference was severe, and in order to prevent this, it was large and expensive. The disadvantage was that it required the addition of noise prevention circuits such as coils and capacitors.

The present invention takes advantage of the unique properties of storage type water heaters, which require a large amount of power to accelerate the heating rate when heating up, but only require a small amount of power to keep warm after reaching the set temperature. , the above-mentioned drawbacks of the prior art are solved by a configuration that uses both ON-OFF control and phase trigger control 3 that triggers at a limited phase.

The first page shows a circuit diagram of an embodiment of the temperature control device for a hot water storage type electric water heater of the present invention.

1 is an AC power supply, 2 is a power switch, 3°4.5.
6 is a diode that performs full-wave rectification of the AC power source 1.

7 is a diode, 8 is a resistor, 9 is a capacitor, and 10 is a Zener diode, and 7 to 10 provide a constant DC voltage for the circuit.

11.12 is a resistor, 13 is a transistor, and 1.
Zero cross pulses are obtained from 1 to 13.

14 is a heater that heats the stored hot water; IEl:t is a semiconductor element that controls energization of the heater; 16 is a diode;
A pulse transformer 7 applies a trigger pulse to the gate of the semiconductor element 16. 1 is a sensor that detects the hot water storage temperature, and in this example, it is a variable resistor that sets negative 1 sense #, A tl (using an anti-element. 19), and 1 control φ11θ. Reference numeral 20 denotes an ON-OFF circuit that turns the semiconductor element-1 ON and OFF in accordance with the signal from the sensor 18. 21, 22, 23, and 24 are resistors, which together with the sensor 18 and variable resistor 19 constitute a bridge.

A comparator 26 compares the midpoint potentials of the bridges. 26 is a resistor, 2'7.28 is a diode, 29 is a resistor, 30 is a transistor, and the pulse transformer 17
'' is turned ON-OFF at zero cross.

31 is a phase trigger circuit that triggers the semiconductor element at a limited phase in accordance with the signal from the sensor 18. The bridge of this phase trigger circuit is shared with the bridge of the ON-OFF circuit, but the midpoint potential is lowered by the voltage drop across the resistor 23. A comparator 32 compares the midpoint potentials of the bridges. 33, 34, 35 are resistors, 36 is a capacitor, and 37 is a comparator. 34 to 37 constitute a timer, and a resistor 38 and a capacitor 39 are used to energize the pulse transformer 17 at regular intervals. 40 is a resistor, 41 and 42 are diodes, 43 is a resistor, 44 is a transistor, and 46 is a resistor, which constitutes a synchronization circuit for the timer. In addition,
The output configuration of the comparator used here is an open collector type.

The operation of the above configuration will be explained with reference to the stored hot water temperature start-up characteristic diagram and the heater energization waveform diagram in FIG. In FIG. 2, the horizontal axis shows the elapsed time t, and the vertical axis shows the stored hot water temperature T. Ts is the set temperature. Also, write together with the elapsed time t,
A heater energization waveform diagram is shown. The black area of the AC power supply indicates the energized state.

During the rising period, the temperature detected by the sensor 18 is considerably lower than the set temperature Ts, so the comparator 25 always outputs 0FFl,
ing. Further, since the pace voltage of the transistor 13 disappears at the zero cross point of the AC power supply 1, the transistor 13 is also turned off. Therefore, resistance 26. diode 27
A pace current is supplied to the transistor 30 through the pulse transformer 17, and the transistor 30 is turned on. The semiconductor element 15 is zero-cross triggered through the pulse transformer 17, and the heater 14 is turned on (fully energized) as in period a in FIG. . Therefore, the temperature of the stored hot water rises rapidly. When the stored hot water temperature reaches Tn in the vicinity of the set temperature Ts after the elapse of time to, the comparator 26
turns ON and cuts off the pace current of the transistor 30, so the transistor 3o is always OFF L and stops turning ON at zero cross. On the other hand, in the period, the comparator 32 is at the end.
I'm on FF. At this time, since the transistor 13 is turned off at the zero cross point, the resistor 40. A pace current is supplied to the transistor 44 via the diode 42, and the transistor 44 is turned on to rapidly discharge the charge accumulated in the timer capacitor 36 via the resistor 45, making the charge zero. When the zero cross point is passed, the transistor 13 is turned on again and the base current of the transistor 440 is cut off, so the transistor 44 is turned off and the timer capacitor 36 starts charging from the zero cross point.

After a certain period of time, the comparator 37 turns on and the capacitor 39
The pulse transformer 17 is turned on via the semiconductor element 15.
is triggered to energize the heater 14. At the next zero cross point, the transistor 44 is turned on again, and after discharging the charge in the timer capacitor 36 and making it zero, the transistor 44 is turned off again and charging starts 71. - Therefore, the semiconductor element operates so that it is always triggered with a constant phase. The above-mentioned phase is set to a value that can supply power slightly higher than the heat radiation loss of hot water storage. For example, if the maximum value of heat radiation loss is 15 W, the phase is set to a value that can supply power of 20 W. During the above-mentioned period, the temperature further increases gradually, and in period C after reaching the set temperature Ts, the comparator 32 is also ONL, and in order to keep the charge of the timer capacitor 36 at zero, the comparator 37 is always OFF. , the semiconductor element is not triggered and the heater 14 is de-energized. When the hot water temperature gradually decreases by turning off the heater energization, the comparator 32 is turned off again, a phase trigger is performed, and in the end, in the heat retention period B, the set temperature is maintained by repeating the phase trigger b period and the OFF period. It is.

Therefore, the entire energization period a appears only in the rising period m, so there is almost no flicker, and although it often appears in the phase trigger period or warming period B, it is a phase trigger with extremely small power supply of about 20W. Therefore, the degree of radio frequency induced interference is small, and even if it were necessary to remove the interference, a small coil would be sufficient. Moreover, it has the advantage that fluctuations in the temperature of stored hot water can be suppressed to an extremely small level.

FIG. 3 shows a circuit diagram of another embodiment of the temperature control device for a hot water storage type electric water heater according to the present invention.

The difference from FIG. 1 is the transistors 46 and 47.

This is the point where resistance 48.49 is added. In the above configuration, as the sensor detected temperature increases from TD in FIG. 2 and approaches the set temperature Ts, the emitter potential of the transistor 46 decreases, the collector potential increases, and the transistor 47 is gradually forward biased, and the resistor The potential determined by 34 and 35 is raised. Therefore, the phase at which the comparator 37 turns on is gradually delayed. Since the transistor 47 cannot lower the potential determined by the resistors 34 and 35, the minimum value of the trigger phase angle is limited, and only phase control after the trigger phase angle is possible. Therefore, it is possible to achieve a temperature control device with less control temperature fluctuation without increasing radio frequency induced disturbances. Oh,
In the previous example of 0N-OFF-[(] path, ON-O by zero cross trigger
I used an FF circuit, but since the 0N-OFF frequency is low,
There is no particular need for a zero cross trigger.

As described above, the temperature control device for a hot water storage type electric water heater according to the present invention has a control circuit that includes an 0N-OFF circuit and a phase trigger circuit that triggers at a limited phase. That's it.

■The degree of interference caused by radio wave induction is small, and even if it were necessary to remove the interference, a small coil would be sufficient.

■ Fluctuations in the temperature of stored hot water can be kept to a minimum.

■Heating start-up is extremely fast, same as before.

It has the following features.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram of an embodiment of the temperature control device for a storage type electric water heater of the present invention, Fig. 2 is a storage hot water temperature rise characteristic diagram and a heater energization waveform diagram in the above embodiment, and Fig. 3 is a diagram of other examples. Circuit diagram in the embodiment 0 14...Heater, 16...Semiconductor element, 18...Sensor, 2o...0N-O
FF circuit, 31... Phase trigger circuit.

Claims (1)

[Claims] The present invention is limited to a sensor that detects the temperature of stored hot water, a heater that heats the stored water, a semiconductor element that controls energization of the heater, and an 0N-077 circuit that turns the semiconductor element ON-OFF in response to a signal from the sensor. 1. A temperature control device for a hot water storage type electric water heater, comprising a phase trigger circuit that triggers at a phase determined by a phase trigger, and a control circuit having a phase trigger circuit.