JPH1122969A - Safety device of hot water supply apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent abnormal operation due to the fluctuation of voltage by monitoring the voltage of a power supply line for supplying power from a power source to a microcomputer and shutting off the supply of fuel by closing a fuel supply valve when the application of a voltage equal to or exceeding a specified level to the microcomputer is detected. SOLUTION: Supplied water is heated by a burner in a heat exchanger, and a main solenoid valve interposed in a fuel supply line to the burner is used so as to supply or shut off fuel. In this case, in a safety device 21 provided in a controller of a hot water supply apparatus, voltage on a power supply line 23 from a power source 22 to a microcomputer 24 is monitored by a power source voltage monitoring means 25 and monitoring output is outputted to a valve drive control means 26. When the power source voltage monitoring means 25 outputs a voltage higher than a reference voltage Vs of the microcomputer 24 from a compactor 27, supply of the fuel is shut off by the valve drive control means 26 so that a situation wherein the microcomputer operates without restriction is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a safety device for a water heater, and more particularly to a device for preventing an abnormal operation due to a fluctuation in a power supply.

[0002]

2. Description of the Related Art Conventionally, as this kind of technique, there is an invention described in, for example, JP-A-63-109501.
This is provided with a detection circuit for detecting runaway of a microcomputer that controls a load, and shuts off power supply to the load via a power switch when the microcomputer runs away, thereby improving safety. .

[0003]

Although such inventions have conventionally existed, the conventional invention has the following problems. In other words, in a system in which runaway of the microcomputer is detected and the energization of the load is cut off thereafter, control cannot be performed properly from the start of runaway of the microcomputer until the energization is cut off. It is not possible to predict whether the operation will take place, and safety measures during that time remain as issues. Further, when an abnormality occurs in the runaway detection circuit itself of the microcomputer, there is a problem that a sufficient response cannot be expected.

Accordingly, the present invention has been made in view of the above-described problems, and has been made in consideration of, for example, runaway of a microcomputer.
It is an object of the present invention to provide a water heater safety device capable of immediately stopping supply of fuel when an applied voltage exceeding an allowable range, which is a main cause of a microcomputer abnormality, is detected.

[0005]

In order to achieve the above object, according to the first aspect of the present invention, there is provided a fuel supply control valve provided on a fuel supply path for supplying fuel, and a microcontroller for controlling hot water supply. A computer, a power supply voltage monitoring unit that monitors a voltage of a power supply line that supplies power to the microcomputer from a power supply, and the power supply voltage monitoring unit detects that a voltage equal to or higher than a predetermined voltage is applied to the microcomputer. Valve drive control means for closing the fuel supply valve and shutting off the supply of fuel.

According to the first aspect of the present invention, the supply of fuel to the water heater is immediately stopped by detecting a supply voltage higher than the allowable range of the microcomputer, which is a main cause of the microcomputer abnormality.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic explanatory view of a water heater to which the present invention is applied, and FIG. 2 is a configuration diagram of a water heater safety device of the present invention.

First, the schematic configuration of a water heater will be described with reference to FIG. 1. In this embodiment, water that has been supplied by a water inlet pipe 2 is heated by a heat exchanger 1 and discharged from a hot water pipe 3. Inlet pipe 2
Is provided with a water supply amount sensor 4 and a water supply temperature sensor 5, and a water supply temperature sensor 6 and a flow control valve 1
1 is provided. The heat exchanger 1 is heated by a burner 7, and the amount of heat to be heated is adjusted by a proportional valve 9 provided on a fuel supply path 8. Further, an original solenoid valve 10 is provided in the fuel supply passage 8 so that fuel can be supplied or stopped.

The control of the detection operation of the sensors such as the water input amount sensor 4, the water input temperature sensor 5, and the hot water temperature sensor 6,
It is a controller 20 such as a microcomputer that controls the flow control valve 11, the proportional valve 9, and the original solenoid valve 11 for tapping. The controller 20 controls the loads 9, 10, and 11 so as to correspond to the detection values of the sensors 4, 5, and 6 so that the temperature is set based on the operation content of the remote controller 12.

Next, the configuration of a safety device for a water heater will be described with reference to FIG. This safety device is provided in the controller 20 of FIG. The safety device 21 includes a power supply 22
Power supply line 23 to microcomputer 24 from
The power supply voltage monitoring means 25 monitors the above voltage, and outputs the monitored output to the valve drive control means 26. At this time, the power supply voltage monitoring means 25 sets the reference voltage V, which is the allowable voltage of the microcomputer (or a higher voltage).
When a voltage higher than s is output from the comparator 27,
The valve drive control means 26 cuts off the supply of fuel to the water heater.

Here, as an example, the recommended voltage is 4.5.
If you are using a ~ 5V microcomputer,
When a voltage of 7 V or more is supplied, there is a risk that the microcomputer may run away or a failure may start. For example, in such a case, a value of 6.5 to 7 V is selected as the reference voltage Vs. The fuel supply can be shut off by closing the solenoid valve 10 by the valve drive control unit 26. Alternatively, the proportional valve 9 may be fully closed as another method.

In the above-described embodiment, the hot water supply circuit shown in FIG. 1 is merely an example, and it goes without saying that another circuit may be used.

Further, the voltage of the microcomputer shown in the above embodiment is an example, and other voltages may be used. In particular, it goes without saying that the voltage changes when the type of microcomputer changes.

[0014]

As described above, according to the water heater safety device of the present invention, the power supply voltage of the microcomputer is monitored, the fuel supply is cut off when the voltage rises, and the microcomputer operates without control due to runaway or the like. This has the effect of preventing such situations from occurring.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a water heater.

FIG. 2 is an explanatory diagram of a safety device for a water heater.

[Explanation of symbols]

 9 Proportional valve 10 Source solenoid valve 12 Remote controller 20 Controller 22 Power supply 24 Microcomputer 25 Power supply voltage monitoring means 26 Valve drive control means

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kenken Kubotani 93rd Edocho, Chuo-ku, Kobe City, Hyogo Prefecture Noritsu (72) Inventor Mamoru Miyazaki 93rd Edocho, Chuo-ku, Kobe City, Hyogo Prefecture Noritsunai (72) Inventor Masaki Takada 93rd Edocho, Chuo-ku, Kobe City, Hyogo Prefecture Noriuchi Co., Ltd. (72) Inventor Masatsugu Yano 93rd Edocho, Chuo-ku, Kobe City, Hyogo Prefecture Noritsunai Co., Ltd. (72) Inventor Satoru Matsumura 93, Edo-cho, Chuo-ku, Kobe-shi, Hyogo Noriitsu Co., Ltd. (72) Inventor Yasuki Takeda 93-Edo-cho, Chuo-ku, Kobe, Hyogo Noriuchi, Inc. (72) Invention Person Hiroki Yoshino 93 Edo-cho, Chuo-ku, Kobe-shi, Hyogo Noritsu Co., Ltd.

Claims (1)

[Claims] 1. A fuel supply control valve provided on a fuel supply passage for supplying fuel, a microcomputer for controlling hot water supply, and a voltage of a power supply line for supplying power from the power supply to the microcomputer is monitored. Power supply voltage monitoring means, and the power supply voltage monitoring means closes the fuel supply valve and shuts off fuel supply when detecting that a voltage equal to or higher than a predetermined voltage is applied to the microcomputer, and valve drive control means. A safety device for a water heater, comprising: