JPH0411766B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hot air heater that can maintain the temperature of hot air at a desired constant temperature.

Conventionally, this type of combustor is known as one disclosed in Japanese Utility Model Publication No. 18842/1984, which controls the air volume of a combustion blower based on the output signal of a combustion detection element, and also controls the air flow rate according to the temperature of the heat exchanger. As a device for controlling a wind fan, one disclosed in Japanese Patent Application Laid-open No. 14444/1983 is known. However, as known from the above-mentioned publication, the hot air fan is merely controlled according to the temperature of the heat exchanger.

However, in this type of device that controls the temperature of the heat exchanger, due to the temperature unevenness of the heat exchanger, when a heat-sensitive element is installed in a place with a high temperature, the temperature must be adjusted accordingly. The rotational speed of the wind fan tends to be high, and conversely, when a heat-sensitive element is installed in a place with a low temperature, the rotational speed of the hot air fan tends to be low accordingly, and the heat radiation amount of the heat exchanger and the hot air The rotational speed of the fan does not match, which causes problems such as the heat exchanger temperature rising excessively, the hot air temperature becoming too high, and conversely the hot air temperature becoming too low. .

Therefore, it is possible to place a heat-sensitive element that controls the air volume of the hot air fan on the combustion surface of the burner, which can detect a stable temperature proportional to the amount of combustion. When placing both heat-sensitive elements facing the burner, the air volume of the combustion blower and the air volume of the hot air fan may not match due to variations in the performance of both temperature-sensitive elements, resulting in a feeling of cold air or vice versa. There is a risk of excessive temperature rise.

The purpose of the present invention is to provide a warm air heater that does not have such inconveniences, and includes a blower for blowing combustion primary air that supplies combustion detection to a burner, and a blower that blows the heat of the burner as warm air. In a type that is equipped with a hot air fan to emit hot air and controls the amount of gas supplied to the burner, a thermocouple or other heat-sensitive element is provided facing the burner, and the combustion blower and the hot air fan are provided with a thermocouple or other heat-sensitive element facing the burner. The airflow rate is controlled to increase or decrease according to the output of the heat-sensitive element.

An example of implementing the present invention will be explained with reference to the attached drawings.
In the drawings, reference numeral 1 denotes an outer casing having an intake port 1a on the upper back and a hot air outlet 1b on the lower front, 2 a hot air fan provided in a position opposite to the intake port 1a of the outer casing 1, and 3
3a is a heat exchanger equipped with a surface-combustion type gas burner 4 provided in the outer casing 1, 3a is an auxiliary heat exchanger following this, 5 is a gas supply path for supplying fuel gas to the gas burner 4; The gas supply path 5 includes a first solenoid valve 6 on the upstream side, a second solenoid valve 7 on the downstream side, a governor 8 interposed therebetween, and a side passage 9 parallel to the second solenoid valve 7. Depending on the room temperature, when the temperature falls below the set temperature, the second solenoid valve 7 is opened to increase the amount of gas supplied to the burner 4 to the desired amount, and when it exceeds the set temperature, the second solenoid valve 7 is opened. The solenoid valve 7 is closed to reduce the amount of supplied gas to the desired amount by supplying gas through the side passage 9, and when the room temperature further rises, the first solenoid valve 6 is closed and the gas burner is turned off. A three-stage switching control is performed to stop the supply of fuel to No. 4.

10 is a blower for supplying primary air for combustion to the gas burner 4; 11 is a thermocouple as a heat-sensitive element facing the front of the combustion surface of the gas burner 4;
By controlling the rotational speed of the combustion blower 10 and hot air fan 2 to increase or decrease in accordance with the output signal of the thermocouple 11, it is possible to obtain a supply amount of primary air and a hot air fan air volume that match the combustion state of the gas burner 4. I did it like that.

To explain this in detail below, the control of the blower 10 for supplying primary air for combustion is performed by a rotation command circuit 12 that generates a rotation command signal according to the output of the heat-sensitive element 11, and a rotation command circuit 12 that generates a rotation command signal according to the output of the heat-sensitive element 11, as shown in FIG. a rotation speed detection pickup coil 13; a rotation speed detection circuit 14 that generates a signal according to the actual rotation speed of the blower 10 based on the output from the rotation detection pickup coil 13 of the blower 10; both circuits 12;
A differential amplifying circuit 15 is provided to input the signal from the differential amplifying circuit 14, and the power transistor 16 for controlling the rotation of the drive motor 10a of the blower 10 is actuated by the output of the differential amplifying circuit 15. , 14 so that the deviation of the signals from them becomes zero, and thus the amount of primary air can be obtained in accordance with the change in the output signal of the heat-sensitive element 11, that is, the combustion state of the gas burner 4. did.

The hot air fan 2 is controlled by a control circuit 17 of the hot air fan 2 by switching its rotation speed into three stages: large, medium and small. 2 is set to strong, medium, and weak, and the resistors 17a, 17b,
Relay contacts of relays Rx, Ry, and Rz that selectively excite 17c according to the output signal of the thermocouple 11
It is now possible to select by opening and closing rx, ry, and rz to rotate at a predetermined rotation speed.

To explain this further, the control circuit 17 inserts the output signal of the thermocouple 11 into each of the positive input terminals of the three comparators 18, 19, 20, and When an output larger than the voltage value set in the resistors 21, 22, 23 connected to the input terminals is obtained at the positive input terminal of each comparator 18, 19, 20, each comparator 18, 19,
20 and each comparator 18,1
9, 20, the relays Rx, Ry,
The emitter collectors of the transistors Tx, Ty, and Tz, in which Rz is interposed as a switching element, are made conductive to excite the relays Rx, Ry, and Rz, thereby switching the contacts rx, ry, and rz. .

Next, the operation of this device will be explained.

When the room temperature is lower than the set temperature, the second solenoid valve 7
The valve is opened and combustion occurs in a so-called strong combustion state in which a large amount of gas is supplied to the gas burner 4. Therefore, the thermocouple 11
The output of the primary air supply fan 10 also increases, and accordingly, the blower 10 for primary air supply rotates at a high rotation speed set in the rotation speed command circuit 12, and each of the comparators 18, 1
Outputs are generated at all output terminals 9 and 20. For this reason, each relay Rx, Ry, Rz is excited, and its contacts rx, ry, rz are switched as shown by dotted lines in FIG. 4 to select the resistor 17c that sets strong rotation. For this reason,
The hot air fan 2 rotates strongly and quickly heats the room. Then, when the room temperature exceeds the set temperature and the solenoid valve 7 closes so that gas is supplied only through the side path 10, the output of the rotation speed command circuit 12 is reduced and the thermocouple 11 is The output signal is also reduced, so that only the comparators 19 and 20 produce output, and the relay Ry is demagnetized and its contact ry
returns to the state shown by the solid line in FIG. Therefore, the rotational speed of the blower 10 for supplying primary air is reduced.

When the room temperature further rises, the first solenoid valve 6 is closed to cut off combustion in the gas burner 4, and the blower 10 for supplying primary air is stopped.

However, since the thermocouple 11 has a slight output due to the residual heat of the gas burner, it produces an output only to the comparator 20 and continues to excite only the relay Rz. Therefore, it is possible to prevent a state in which the resistance for weak rotation is selected by the contact point rz of the relay Rz, and a state in which cold air is blown out.

Then, when the room temperature drops again, the solenoid valves 6 and 7 open sequentially in response to this, and combustion in the gas burner 4 increases accordingly, and the temperature of the combustion surface of the gas burner 4 also increases, causing the output signal of the thermocouple 11 to increase. In response to this increase, the rotation speeds of the hot air fan 2 and the blower 10 for supplying primary air also increase as described above.

Note that if the solenoid valve 6 to be extinguished is closed, combustion in the gas burner 4 will end, but since the combustion surface of the gas burner 4 has residual heat, the thermocouple 11 will not immediately lose its output, and therefore the thermocouple 11 will be extinguished. After that, an output is generated for a certain period of time, which continues to rotate the hot air fan 2, and the output from the comparator 21 is not lost until the temperature of the gas burner 4 starts to drop.
Open contact rz to stop hot air fan 2. In FIG. 4, 24 is a main switch, 25 is a bimetal switch in parallel with the relay contact rz, and 26 is an amplification circuit for amplifying the electromotive force of the thermocouple. In the illustrated embodiment, each air volume is controlled by controlling the rotational speed of the blower 10 and fan 2, but this is achieved by adjusting the opening degree of a damper (not shown) provided on each blower 10 or fan 2. Needless to say, the air volume can be adjusted by doing so. As described above, according to the present invention, a burner is provided with a combustion blower that supplies combustion air to a burner, and a hot air fan that blows heat from the burner as hot air, and that controls an increase or decrease in the amount of gas supplied to the burner. A thermocouple or other heat-sensitive element is installed in front of the combustion air fan, and the air volume of the combustion blower and the hot air fan is controlled to increase or decrease according to the output of the heat-sensitive element. There is no error due to variations in the performance of the heat-sensitive elements, which is the case when controlling each heat-sensitive element, and various inconveniences caused by this can be eliminated.

[Brief explanation of drawings]

Fig. 1 shows an example of the implementation of the present invention, and Fig. 2 is a cut-away side view, Fig. 2 is a cross-sectional view taken along the - line, Fig. 3 is an operating circuit diagram, and Fig. 4 is a control circuit of a hot air fan. . 2... Hot air fan, 10... Blower for blowing primary air for combustion, 11... Heat sensitive element.

Claims (1)

[Claims] 1 A type that is equipped with a combustion primary air blower that supplies combustion air to the burner, and a hot air fan that blows out the heat of the burner as hot air, and that controls the increase or decrease of the amount of gas supplied to the burner. A hot air heater characterized in that a thermocouple or other heat sensitive element is provided facing the burner, and the air volume of the combustion blower and the hot air fan is controlled to increase or decrease according to the output of the heat sensitive element. .