JPH057625B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a control circuit for a water heater, and particularly to a circuit that continuously displays the amount of hot water remaining in the water heater.

Conventional configuration and its problems When displaying the amount of hot water remaining in a conventional water heater control circuit, it is common to display a bar graph using LEDs using multiple thermistors as sensors. However, due to variations in the thermistor, there is a risk that the bar graph will not be displayed continuously but will be displayed in a so-called "missing" manner, where the graph is missing in the middle, giving the user a sense of anxiety that the display may be malfunctioning. It was hot.

FIG. 1 shows the configuration of the remaining hot water display in a conventional water heater. 1 is a hot water storage tank; 2a to 2c are thermistors that detect the amount of remaining hot water; 3 is a hot water supply port; 4 is a water supply port; 5 is a control circuit that transmits a display signal to the remaining hot water indicator 7;
is a transmission cable.

FIG. 2 shows the configuration of a remaining hot water display circuit in a conventional water heater. The operation will be briefly explained below.

The temperature of the water inside the hot water storage tank 1 is determined by the thermistor 2a.
Consider the case where the temperature is stabilized slightly higher than the detected temperature of ~2c. If there is sufficient hot water inside the can, the comparators 8 to 10 connected to the thermistors 2a to 2c output signals for detecting remaining hot water. This residual water detection signal
It is applied to the LED drivers 11 to 13, and the LEDs 14 to 17 indicating the remaining hot water are turned on. LED17 is always lit. However, the thermistors 2a-2
There is no problem if all c are operated at the same temperature, but inconvenient phenomena may occur due to variations in the characteristics of the thermistors. For example, even though there is sufficient hot water in the hot water storage tank 1, if the comparator 9 does not output a signal to detect remaining hot water due to variations in the characteristics of the thermistor 2b, the LEDs 14, 16, 1
LED 7 is on and LED 15 is off, resulting in a so-called "blank" state. FIG. 3a shows a normal state, and b shows an abnormal display of missing teeth (hatching indicates a lit state). If the display becomes blank,
This has problems in that it is not possible to accurately display the amount of remaining hot water, and it makes the user feel uneasy about whether the equipment is malfunctioning.

Purpose of the Invention In view of the above-mentioned conventional problems, the present invention eliminates the incomplete display of remaining hot water in a water heater, thereby eliminating the user's sense of anxiety and providing a more accurate display of remaining hot water.

Structure of the Invention In order to achieve the above object, the basic structure of the present invention includes an upper hot water supply inlet, a lower water supply inlet, and a plurality of water supply ports provided at each fixed tank capacity from the hot water supply inlet to detect the water temperature. When the sensor detects a temperature above a certain level, the display element of the remaining water indicator corresponding to the sensor lights up, and when the sensor installed at the bottom detects a temperature above a certain level, the display element is turned on. , the display element corresponding to this sensor is turned on regardless of the presence or absence of a signal from the sensor provided above.

Description of examples FIG. 4 shows a circuit diagram of this embodiment.

Thermistors 2a to 2c are used as sensors for detecting the amount of remaining hot water, and the thermistor 2a is provided at the upper part of the hot water storage tank 1, the thermistor 2c is provided at the lower part of the hot water storage tank, and the thermistor 2b is provided in between. Consider a case where the temperature of the hot water inside the hot water storage tank 1 stabilizes at a temperature slightly higher than the temperature detected by the thermistors 2a to 2b. If there is a sufficient amount of hot water inside the hot water storage tank 1, the thermistors 2a to 2b
The comparators 8 to 10 connected to each output a signal for detecting remaining hot water. This remaining hot water detection signal is given to the LED drivers 11-13, and the remaining hot water display LEDs 14-17 are turned on. LED17 is always lit. The above is normal operation. However, even though there is enough hot water to reach the bottom of the hot water storage tank 1, due to variations in the thermistor and circuit elements, the comparator 9 connected to the thermistor 2b in the center of the hot water storage tank 1 does not detect a signal to detect remaining hot water. Considering this, the LED driver 12 cannot drive the LED 15. Conventionally, the display would be in a blank state as shown in FIG. 3b. In this embodiment, since there is enough hot water to reach the bottom of the can, the comparator 8 connected to the thermistor 2c at the bottom of the hot water storage tank 1 outputs a signal to detect remaining hot water, and the LED driver 11 causes the LED to
14 lights up. Since the LED 15 is connected to the LED driver 11 via the diode 19, even if the LED driver 12 does not operate, the LED 15 is turned on by the LED driver 11, and the blank state display disappears. The above are the basic operations to prevent the situation of missing gears. Similarly, LED driver 12
is lit by a signal from the comparator 10 connected to the thermistor 2a at the top of the hot water storage tank 1.
Diode 2 to light up LED 16 at the same time
It is equipped with 0.

In addition, in FIG. 4, 18 is a power supply circuit block,
21 to 25 are reference resistances that determine the temperature of residual hot water detection;
26-28 are pull-up resistors for comparator output, 29-32 are LED current limiting resistors 33-3
5 represents the feedback resistance.

Effects of the Invention As described above, according to the present invention, the remaining hot water indicator does not display a missing part in the middle, which causes the user to feel uneasy about whether the indicator is malfunctioning. It has the effect of being safe to use.

[Brief explanation of the drawing]

Figure 1 is a block diagram of the water heater and remaining hot water indicator, Figure 2 is a block diagram of a conventional remaining hot water display circuit, and Figure 3 is the status of the remaining hot water display, where a is normal and b is a missing status. FIG. 4 is a configuration diagram of an embodiment of the present invention. 1...Hot water storage tank, 2a-2c...sensor,
3...Hot water supply inlet, 4...Water supply inlet, 7...Remaining hot water indicator.

Claims (1)

[Claims] 1.Equipped with an upper hot water inlet, a lower water inlet, and a plurality of sensors installed at each fixed tank capacity from the hot water inlet to detect the water temperature, and when the sensor detects a temperature above a certain level, the sensor In addition, when the sensor installed at the bottom detects a temperature above a certain level, the display element of the remaining water indicator corresponding to The water heater's remaining hot water display circuit also lights up the display element corresponding to the upper sensor.