JPH0142770Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention provides a valve for changing the amount of fuel supplied to a burner for a water heating heat exchanger, and a power source for a fan that supplies fuel air to the burner. to the circuit,
The present invention relates to an improvement in a water heater that is equipped with an electric resistance circuit for changing the amount of air blown by the fan and an electric heater that prevents the water in the heat exchanger from freezing.

[Prior Art] Conventionally, in configuring the electric circuit of the above-mentioned water heater, as shown in FIG.
and a circuit 16A that bypasses the electrical resistor R are provided in parallel, and as the fuel supply amount is changed by the valve, a state in which power is supplied via the electrical resistor R and a state in which power is supplied by bypassing the resistor R are provided. Then, the power supply circuit of the fan is changed with the switch 17, and the amount of combustion air supplied by the fan 5 is changed to an amount commensurate with the amount of supplied fuel, and the air-fuel ratio is set to an appropriate value regardless of the switching of the heating capacity due to the change in the amount of fuel supplied. It was configured to be maintained.

In the figure, numeral 15 denotes an antifreeze heater consisting of a heat generating electric resistor 15A.

[Problems to be solved by the invention] However, in the conventional configuration described above, the structure for changing the air flow rate of the fan can be configured only by interposing an electrical resistor to the power supply circuit without any improvement of the fan itself. Although the structure is simple and low cost, the heat generated by the electric resistor when power is supplied through the electric resistor at low airflow rates has an adverse effect on peripheral control equipment, leading to control troubles. There was a risk that the control equipment would be damaged prematurely, and the heat generated itself caused energy loss.

The purpose of this invention is to make a rational improvement using the originally equipped electric heater to prevent freezing, thereby further simplifying the structure and reducing the adverse effects on peripheral control equipment and energy loss due to the heat generated by the electric resistor for changing the air volume. The point is to avoid.

[Means for solving the problem] The characteristic configuration of the water heater according to the present invention is that the heating resistor of the electric heater for freezing prevention is the resistor of the electric resistance circuit for changing the air volume. is as follows.

[Function] In other words, by focusing on the fact that the anti-freezing electric heater is in a dormant state when the burner is in a combustion state, the heating electric resistor of the electric heater in a dormant condition is replaced with the fan's air volume changing electric resistor. By supplying power to the fan through the heating electric resistor in the dual-use state, the amount of air blown by the fan is reduced when the heating capacity is low.

[Effects of the invention] As a result of the above, it is possible to omit the electric resistor dedicated to changing the air volume, which further simplifies the overall structure and reduces costs.Moreover, due to the original configuration, the heat generating resistor of the electric heater is part of the controller. Since it is placed in the heat exchanger for water heating, which is separate from the heat exchanger for water heating, it is possible to reliably prevent the heat generated by the electric resistor, which also serves for changing the air volume, from having an adverse effect on peripheral control equipment, and to reduce the amount of heat generated. It can be applied to a heat exchanger and used effectively to heat water, and energy loss due to heat generation can be avoided. Overall, the water heater has excellent controllability and thermal efficiency, and is also compact and inexpensive.

[Example] Next, embodiments will be described based on the drawings.

As shown in FIG. 1, a heat exchanger 2 that heats the water supplied to the outlet pipe 1 and a burner 3 for the heat exchanger 2 are installed in a casing 4, and combustion air is supplied to the burner 3. In addition, an electric fan 5 is provided to supply fuel gas to the burner 3.
, an electromagnetic valve 7 for intermittent gas supply, an electromagnetic control valve 8 for changing the heating capacity of the burner 3 by changing the amount of supplied gas, and a constant flow valve 10 for the water supply pipe 9 to the heat exchanger 2. , and a water flow switch 11 are provided respectively.

Based on the ON/OFF operation of the water flow switch 11 accompanying the manual opening/closing operation of the tap 12, the electromagnetic valve 7 is opened/closed, the burner 3 is ignited by the igniter 13, and the fan 5 is started/stopped. A controller 14 is provided to perform this, thereby configuring a so-called stop-start gas instantaneous water heater.

An electric heater 15 is attached to the water heating heat exchanger 2, and the heat exchanger 15 is configured to prevent the water in the heat exchanger 2 from freezing.

The fan 5 and the antifreeze electric heater 1
5, the fan power supply circuit 16 is composed of two parallel circuits 16A and 16B, and these parallel circuits
One of A and 16B is supplied to the electric resistance circuit 16B which supplies power to the fan 5 via the heating electric resistor 15A of the electric heater 15, and the other is supplied with power without going through the electric resistor. A relay switch 17 is formed in the bypass circuit 16A and selectively connects both circuits 16A and 16B to the fan 5. By the switching operation, when the heating capacity is low, the amount of air blown by the fan 5 is reduced by supplying power via the electrical resistance circuit 16B, and when the heating capacity is high, the amount of air blown by the fan 5 is reduced by being supplied with power via the bypass circuit 16A. The configuration is such that the air-fuel ratio is maintained at an appropriate value regardless of heating capacity switching due to changes in fuel supply amount.

Also, paying attention to the fact that the electric heater 15 is essentially in a dormant state when the burner 3 is in the combustion state, the heat generating electric resistor 15A of the electric heater 15 is replaced with the resistance of the air volume changing electric resistance circuit 16B as described above. It is used for both purposes on the body.

In FIG. 2, 18 is the water flow switch 11.
In conjunction with the ON operation, an electric heater 15 for antifreeze
This is a relay switch that reversibly switches the power supply circuit from an operating state to a fan 5 drive state.

19 is a thermostat for the electric heater 15 for freezing prevention.

20 is an operation switch, and 21 is a control circuit.

Note that the specific resistance value of the heating electric resistor 15A in the electric heater 15 can be changed as appropriate.

Further, various improvements can be made to the specific circuit configuration for using the heating electric resistor 15A as an air volume changing electric resistor.

The fuel supplied to the burner 3 does not matter.

This invention is not limited to stop-start gas instantaneous water heaters.
Applicable to various types of water heaters.

[Brief explanation of drawings]

1 and 2 show an embodiment of the present invention, with FIG. 1 being an overall schematic diagram and FIG. 2 being an electrical circuit diagram. FIG. 3 is an electrical circuit diagram showing a conventional configuration. 2... Heat exchanger for water heating, 3... Burner, 5...
…Fan, 8…Valve, 15…Electric heater,
15A... Electric resistance element for heat generation, 16... Power supply circuit, 16B... Electric resistance circuit.

Claims (1)

[Scope of utility model registration request] A valve 8 for changing the amount of fuel supplied to the burner 3 with respect to the water heating heat exchanger 2 is provided.
Power supply circuit 16 of fan 5 that supplies combustion air to
The water heater is equipped with an electric resistance circuit 16B for changing the amount of air blown by the fan 5, and an electric heater 15 for preventing the water in the heat exchanger 2 from freezing. Heat generating resistor 1 of heater 15
A water heater in which 5A is a resistor of the electric resistance circuit 16B.