JPH0335579B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to water heating apparatuses such as gas or oil water heaters.

BACKGROUND TECHNOLOGY As shown in FIG. 3, a conventional water heater of this type has an air supply section 13 consisting of a combustion fan 11 and an air passage 12, a fuel supply section 15 consisting of a nozzle block 14, etc., a burner 16, and a combustion chamber 17. It consists of a combustion section 18, a heat exchanger 19, an exhaust gas pipe 20, etc., and as shown by the solid arrow, combustion air is passed from the combustion fan 11 through the air passage 12 to the nozzle block through the fuel pipe and closing cock 21. Fuel is supplied from 14 to a burner 16 and burned in a combustion chamber 17. Also, the exhaust gas after combustion is
As shown by the dashed arrow, the gas passes through a heat exchanger 19 and an exhaust gas pipe 20, where it exchanges heat with the water passing through the water supply pipe 22, and is released into the atmosphere. or,
The combustion fan 11 that sends combustion air is composed of a combustion fan main body and a motor, and the invention that uses a condenser motor or a circular ring type motor powered by single-phase alternating current as the drive motor would solve the problem. However, with the above configuration, the starting torque of the combustion fan drive motor is small, so transient characteristics such as starting and stopping are poor. In a series of hot water supply systems that open and detect water flowing into the water supply pipe, operate the fuel supply unit and combustion fan, and ignite the water, it takes a long time to obtain hot water and good hot water delivery characteristics cannot be obtained. . In addition, the rotation speed cannot be increased above the synchronous speed with the frequency of the power supply, and the variation range of the rotation speed cannot be changed significantly due to the constraints of synchronous speed or forced slip rotation in the future. The problem was that it was not possible to miniaturize the equipment due to the variable nature and high load of the burner.

The present invention solves this problem, and by using a DC brushless motor as the drive motor of the combustion fan, it improves the response of the combustion fan, expands the speed control range, and makes it more compact and high-pressure. The purpose is to improve characteristics, save energy, and achieve miniaturization.

Means for Solving the Problems In order to solve the above problems, the water heater of the present invention includes a burner in the main body of the water heater, a heat exchanger for supplying hot water heated by the burner, and a supply of combustion air to the burner. A combustion fan is provided, and the combustion fan includes a DC brushless motor that rotates the fan, and a drive circuit that controls the rotation speed of the DC brushless motor.

Effects According to the above-described configuration, the present invention uses a DC brushless motor as the motor for driving the combustion fan of the water heater, so that the combustion fan itself can have high responsiveness and a wide range of speed control, and as a result, the combustion The time for which air is supplied to the burner is shortened, and
The amount supplied will also be wide-ranging.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a gas water heater as an example, 1 is a combustion fan, 2 is a DC brushless motor for driving the combustion fan 1, and this DC brushless motor 2
The rotation speed is controlled by a drive circuit 9 formed of, for example, a transistor. Reference numeral 10 denotes a current limiting section provided to protect the drive circuit 9 of the DC brushless motor 2 from a sudden starting current that flows when the DC brushless motor 2 is started.

3 is an air passage that supplies the air necessary for combustion to the burner 5, and the air flows as shown by the solid arrow to the burner 5.
is released into the atmosphere as exhaust gas through combustion.
The amount of heat generated in the exhaust gas is exchanged with water flowing through the water supply pipe 7 in a heat exchanger 6 placed midway, and hot water is obtained from the hot water supply port 8. Reference numeral 4 indicates a closing hole provided in the middle of the fuel supply pipe. 20 is the main body of the water heater.

In the above configuration, since the combustion fan 1 is driven by the DC brushless motor 2 with a large starting torque, the combustion fan itself has high responsiveness to starting and stopping, and the air blown by the combustion fan 1 is The time to be supplied to the burner 5 can be shortened, making it possible to follow the response time of the fuel supply side.
For example, the time it takes for hot water to come out of the shower can be cut in half compared to the conventional method, and good hot water performance can be obtained even when the hot water faucet is opened or closed mid-way, or when the flow rate changes suddenly. Furthermore, since it has a speed control characteristic that allows the rotation speed to be varied over a wide range, the optimum air ratio can be set for the combustion range when the burner 5 is placed under a high load, and good combustion characteristics can be obtained over a wide range.
Furthermore, unlike a DC motor, the DC brushless motor 2 does not have brushes that are mechanically worn parts, so even if gas leaks from the fuel supply system installed in the same space in the water heater, There is no risk of explosion due to the generation of sparks, and in response to recent low-noise equipment, there is no brush noise and the service life can be extended.Furthermore, there is no noise caused by sparks generated by the brushes, making it easier to heat hot water. There is no influence of noise on the control circuit, etc. that performs control, and malfunctions can be prevented.

In addition, it is possible to achieve a rotation speed that is higher than the synchronous speed of the power supply frequency, and the pressure and air volume characteristics of the fan are controlled by the law of proportionality of pressure, which is approximately proportional to the square of the number of rotations, and the proportional law of air volume, which is approximately proportional to the number of rotations. increases significantly. FIG. 2 shows an example of this. In Fig. 2, the fan shown as a conventional example is used in condenser mode at a rotation speed of 2800 rpm.In this case, the impeller diameter is 180 mm, and when operated in two stages in series. be. On the other hand,
In the present invention, the same pressure and air volume characteristics increase the rotation speed.
By setting the speed to 6300rpm, it is shown that the impeller diameter is 110mm and a single stage fan can be used.
Therefore, the volume ratio including the DC brushless motor 2 can be reduced to about 1/4, and the water heater can be made smaller and more compact.

In this embodiment, the case where the combustion fan and the DC brushless motor 2 are arranged on the air supply side is exemplified, but a method in which the combustion fan and the DC brushless motor 2 are arranged on the exhaust side and the combustion exhaust gas is forcibly discharged can also be used. There is no problem at all as long as the influence of exhaust heat on the DC brushless motor 2 is taken into account.

Effects of the Invention As described above, the water heater of the present invention provides the following effects.

(1) Hot water can be supplied quickly by using a water heater that uses a DC brushless motor as the drive motor for the combustion fan.

(2) Even if fuel leaks, there is no risk of ignition and explosion due to sparks.

(3) Reliability can be improved because there is no noise that can cause malfunction in the hot water supply control circuit.

(4) Since there are no mechanically worn parts, low noise and long life can be achieved.

(5) High load on the burner and miniaturization of the fan itself are possible, making it possible to make the water heater smaller and more compact.

[Brief explanation of the drawing]

Fig. 1 is a configuration diagram of a hot water supply system using a combustion fan according to an embodiment of the present invention, Fig. 2 is a pressure-airflow characteristic diagram of the fan showing a comparison with a conventional fan, and Fig. 3
The figure is a configuration diagram of a water heater using a conventional combustion fan. 1... Combustion fan main body, 2... DC brushless motor, 5... Burner, 6... Heat exchanger, 9...
drive circuit.

Claims (1)

[Claims] 1 A burner, a heat exchanger for heating hot water heated by the burner, and a combustion fan that supplies combustion air to the burner are provided in the main body of the water heater, and the combustion fan is equipped with a DC brushless motor that rotates the fan. , and a drive circuit that controls the rotation speed of the DC brushless motor.