JPH0534010A - Fan forced heater - Google Patents

Abstract

PURPOSE:To enable execution of a good quality of temperature control during low load operation by providing a fuel device always operated as a heat source during heating operation and an electric heater working only in rise heating. CONSTITUTION:When an operation starting switch S1 is turned ON, simultaneously with turning ON of a combustion control circuit 7, a relay PR for a heater source is turned ON through the normally-opening contact of a relay TR operated by means of an output from a temperature sensor 8. Both a gas burner 2 and an electric heater 3 are operated for rise and heating operation is effected. When a room temperature attains a given value, for example, 20 deg.C, the relay TR is turned OFF, and the relay PR for a heater source is turned OFF, whereby, on and after the above, steady heating (control at 22 deg.C) is effected only by means of a gas burner 2. This constitution enables execution of a good quality of temperature control during low load operation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a compact hot air heater.

[0002]

2. Description of the Related Art In a conventional gas-fired hot air heater, the maximum heat output is a load during steady heating (for example, 1000 kc for 6 tatami mats).
Al / h) about twice (for example, 2000 kcal /
h) was used. When the set temperature of this warm air heater is set to, for example, 22 ° C., the heat output of the heater is a maximum output of 2000 kcal / h at the rising time (t _{0 to} t ₁ ) as shown by the solid line in FIG. It operates and is in steady state (t ₁
After that, that is, after the room temperature reached 22 ° C., the constant temperature control was performed at a constant output of, for example, around 1000 kcal / h, depending on the outside air temperature.

[0003]

However, the combustion type hot air heater using city gas, propane gas, etc. is usually a stationary type, and there is a strong demand for downsizing and weight reduction in order to narrow the living space. Therefore, as described above, adding the heating capacity about twice as much as the steady output is a major obstacle to reduction in size and weight.

If the maximum heat output of the gas burner is made too large with respect to the steady heating load (for example, 1000 kcal / h) (usually about twice), the minimum heat output for preventing unstable combustion also becomes large. On a relatively warm day, the minimum heating capacity of the gas burner becomes excessive, which may make temperature control difficult. 1000 kcal / h
Although the minimum output of the heater of 300 kcal / h is possible, the minimum output of the heater of 2000 kcal / h is about 600 kcal / h, so it cannot support the minimum load of 6 tatami on a relatively warm day, Therefore, when the difference from the outside air temperature is small, the room temperature becomes higher than the set temperature, and normal temperature control cannot be performed.

[0005]

Therefore, the warm air heater according to the present invention is provided with, as a heat source, a combustion appliance 2 which is constantly operated during heating operation, and an electric heater 3 which is operated only during standing heating. For example, a 1000 kcal / h gas burner and a 1000 kcal / h electric heater are used as a heat source of a 2000 kcal / h warm air heater.

[0006]

When the above configuration is compared with a hot air heater (2000 kcal / h) using only the gas burner as a heat source, the gas burner has a capacity of 2000 kcal / h to 1000 kcal / h.
Since the required heat output becomes smaller, the size can be reduced accordingly, and the electric heater is thin and takes up little space. Therefore, it is possible to significantly reduce the size and weight of the heater as a whole, and since the minimum heat output of the gas burner is reduced, it is possible to perform high-quality temperature control for a light load such as early spring.

[0007]

FIG. 1 shows an example of the structure of a warm air heater according to the present invention, in which a gas burner is provided as a combustion instrument 2 in the upper part of a casing 1 of the warm air heater, and a warm air blown at the lower part. A blower fan 5 is provided near the port 4, and a plate-shaped electric heater 3 is attached to an intake port 6 located above.

FIG. 2 exemplifies the control means for operating the electric heater 3 only at the time of rising heating. In the same figure (a), the electric heater is operated only for a fixed time (for example, 30 minutes) from the start of the operation. Now, when the operation start switch S ₁ is turned on, the combustion control circuit 7 is turned on. The gas burner starts operating at the same time, the power relay PR of the electric heater is turned on through the normally closed contact x of the timer T, and at the same time, the timer T starts counting operation. Therefore, in this state, as shown in FIG. 3, both the gas burner (full operation at 1000 kcal / h) and the electric heater (1000 kcal / h) are operated, and rapid heating (2000 kcal / h) is performed. When the set time t ₂ of the timer has elapsed, the timer contact x turns off and the heater power supply relay PR turns off. Therefore, after that, only the gas burner operates and steady heating (for example, 1000 kca
1 / h) is performed (FIG. 3), but it is actually faster that the room temperature reaches the set temperature (t ₁ ) than the time (t ₂ ) when the above-mentioned constant time (30 minutes) elapses. As shown, t ₁
Therefore, the temperature control device of the gas burner is activated to reduce the heat output of the burner, so that the room temperature is maintained at a steady temperature.

In the control circuit shown in FIG. 1B, the room temperature is a set temperature (a user can arbitrarily set it, for example, 22 ° C.).
The electric heater is operated only until it reaches a minus constant value (for example, 2 ° C.). When the operation start switch S ₁ is turned on, the combustion control circuit 7 is turned on, and at the same time, the relay T which operates by the output of the temperature sensor 8 is turned on.
The heater power relay PR is turned on through the normally closed contact point of R, and both the gas burner and the electric heater are operated to start up and perform heating. When the room temperature reaches a predetermined value (20 ° C.), the relay TR is turned off and the heater power relay TR is turned off, so that the stationary heating (control at 22 ° C.) is performed only by the gas burner thereafter.

When a control circuit for rapidly heating the room temperature below a set temperature minus a constant value (2 ° C.) is used as shown in FIG. 2B, when a room window is opened during heating, etc. As described above, when the temperature falls below the steady temperature by 2 ° C. or more, the electric heater is energized again to perform the rising heating in which the room temperature rapidly rises.

[0011]

EFFECTS OF THE INVENTION According to the present invention, the burner itself requires less than the required heat output, while an electric heater is added, but the electric heater itself is inexpensive and does not occupy a lot of space. Helps reduce costs and reduce size and weight. Also, since the minimum heat output of the combustion equipment can be reduced, good temperature control can be achieved when the load is light. On the other hand, the increase in cost per amount of heat due to the use of electric power is only used for a short time at the time of start-up, so that the increase in running cost is hardly a problem. The automatic switching from the standing heating to the steady heating can be easily performed only by turning on / off the electric heater.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a warm air heater showing an embodiment of the present invention.

FIG. 2A is a circuit diagram showing an example of control means in the present invention. (B) is a circuit diagram showing a control means in the present invention.

FIG. 3 is an operation explanatory diagram of the present invention.

FIG. 4 is an operation explanatory diagram of a conventional example.

[Explanation of symbols]

1 case 2 burning appliances 3 electric heaters 4 Hot air outlet 5 Blower fan 6 intake 7 Combustion control circuit 8 Temperature sensor

Claims (3)

[Claims] 1. A warm air heater comprising a combustion appliance as a heat source, which is constantly operated during heating operation, and an electric heater which is operated only during startup heating. 2. The warm air heater according to claim 1, further comprising control means for operating the electric heater only for a certain period when the room temperature rises. 3. The warm air heater according to claim 1, further comprising control means for operating the electric heater only when the room temperature is equal to or lower than a set temperature minus a certain value.