JPS605000Y2 - Combustion control device - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an effective corrosion protection device operation indicator light circuit for a water heater incorporating a cathodic protection device.

A conventional example will be explained with reference to FIG.

Reference numeral 1 denotes an AC power supply, which supplies commercial power to the control device.

It is converted to a low voltage by the control circuit power transformer 2,
It is converted into direct current by a bridge diode 4 and an electrolytic capacitor 6, and is supplied to the combustion control circuit via an operation switch 8.

In addition, the voltage is converted by the power transformer 3 for the anti-corrosion circuit,
The diode 5 and the electrolytic capacitor 7 convert the current into direct current,
It is led through a resistor 10 to a corrosion-proof terminal 12 placed in water.

Reference numeral 13 is a ground terminal connected to the object to be protected from corrosion.

When the anti-corrosion current flows from the anti-corrosion terminal 12 to the ground terminal 13 through the water in the water heater, the transistor 11 becomes conductive and the indicator light (light emitting diode) 14 lights up.

That is, when the anticorrosion current flows, the indicator light 14 lights up.

In such a circuit, since the anti-corrosion current and the current necessary for lighting the indicator light 14 are supplied from the anti-corrosion circuit power transformer 3, a power transformer with a large capacity is used as the anti-corrosion circuit power transformer. There is a need to.

Therefore, there was a drawback that the power transformer 3 for the anti-corrosion circuit became expensive.

The present invention aims to improve these drawbacks.

Generally, in an electrolytic protection device, load fluctuations are large due to resistance changes due to the surface condition of the object to be protected or changes in the temperature of water interposed between the corrosion protection terminal and the object to be protected.

For this reason, in a control device with a built-in cathodic protection device,
The combustion control circuit, which requires a stable power supply, and the cathodic protection circuit, which undergoes large load fluctuations, are usually provided with independent power transformers for each circuit.

In the present invention, power is supplied to the indicator light from a combustion control circuit power transformer.

An embodiment of the present invention will be explained with reference to FIG.

The indicator light 14 is connected to the combustion control circuit side, and is connected to the anticorrosion circuit via a transistor 15.

16.17 is the resistance. In such a circuit, when a current flows from the anti-corrosion terminal 12 to the ground terminal 13, a resistance of 10
A potential is generated across the transistor 11, the transistor 15 becomes conductive, and the indicator lamp 14 lights up.

Since the current flowing between the base and emitter of the transistor 15 is very small compared to the current required to light up the indicator light 14, the resistance value of the resistor 16.17 is increased to It is possible to limit the current flowing.

Therefore, the current flowing through the anti-corrosion circuit power transformer 3 hardly increases, and therefore there is no need to increase the capacity.

In this way, in a combustion control device incorporating a cathodic protection device, a switching circuit for an operation indicator light of the corrosion protection device is provided in the corrosion protection power supply circuit, and current is supplied to the indicator light from the control circuit power supply. Therefore, the power transformer for anti-corrosion circuit can be designed with a capacity of about 172 compared to the conventional one.

In addition, high-capacity power transformers have traditionally been used in combustion control circuits for stable supply, relay drive, etc., and generally have sufficient margin, so power is not supplied to indicator lights. There is no need to increase the capacity.

- Therefore, according to the present invention, it is possible to manufacture an inexpensive control device.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of a conventional example, and FIG. 2 is a circuit diagram of an embodiment of the present invention. 2... Power transformer for combustion control circuit, 3...
... Power transformer for anti-corrosion circuit, 9... Combustion control circuit, 12... Anti-corrosion terminal, 14...
Indicator light.

Claims (1)

[Scope of utility model registration request] In a device that is provided with a power supply circuit that supplies power to the combustion control circuit and a power supply circuit that separately supplies power to the cathodic protection device, the former power supply circuit is connected to an indicator light for indicating the operation of the cathodic protection device. A combustion control device comprising a switching circuit configured to supply power and to drive an operation indicator light by activation of the cathodic protection device.