JPH039382B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a control device for a convection fan in a hot air heater.

(Prior Art) The applicant of the present application has previously proposed a first thermosensor which is linked to the output from a temperature sensing element a facing the burner as shown in FIG.
It was proposed that a switch b drives a convection fan c, and a second switch d, a bimetallic switch, stops the convection fan c (see Japanese Patent Laid-Open No. 169051/1983).

(Problems to be Solved by the Invention) However, the above-mentioned conventional switch requires at least two first switches b, b ₁ for early driving of the rotation speed control circuit e and b ₂ for switching the rotation speed. In other words, a number equal to the number of rotational speeds of the convection fan c is required, which causes the disadvantage that the overall circuit configuration becomes complicated.

(Means for Solving the Problems) The present invention attempts to solve the above-mentioned disadvantages of the conventional system by setting the first switch to a number lower than the number of rotations of the convection fan. The convection fan is driven by a first switch linked to the output from the temperature sensing element, and the convection fan is stopped by a second switch, a bimetallic switch, in which the rotation speed control circuit of the convection fan is connected to the burner. The circuit is configured to include a combustion side circuit of the burner and a combustion stop side circuit of the burner, and both circuits are switched by the first switch, and the bimetal switch is connected to the combustion stop side circuit of the burner. It consists of intervention.

(Function) The present invention has the above configuration, and according to this, when the burner is ignited, the first switch linked to the output from the temperature sensing element causes the rotation speed control circuit of the convection fan to move to the combustion side of the burner. The convection fan is activated by switching to the circuit, and the convection fan is operated at a rotation speed that corresponds to the amount of combustion in the burner, providing heating. After that, when the burner is extinguished, the first switch linked to the output from the temperature sensing element switches the rotation speed control circuit of the convection fan to the circuit for when combustion of the burner is stopped.
The convection fan is kept energized and in operation until the second bimetal switch detects the set temperature, and during that time residual heat is blown out to prevent the main body of the hot air heater from overheating. When the bimetal switch detects the set temperature, the combustion stop circuit of the burner becomes inactive and the convection fan stops.

In this way, the first switch has both the functions of early driving the rotation speed control circuit and switching the rotation speed, so it requires one less switch than the number of rotation speeds of the convection fan, which reduces the overall circuit configuration. It becomes easy.

(Example) Next, an example of the present invention will be described based on the drawings.

In the drawings, reference numeral 1 indicates a hot air heater main body equipped with an internal ventilation passage 1c that communicates between a back suction port 1a and a front hot air outlet 1b.
Convection fan 2 that circulates and blows indoor air through c.
and a combustion case 4 containing a built-in burner 3, and the combustion case 4 is connected to the ventilation passage 1 at the upper end exhaust port 4a.
As the convection fan 2 rotates, the hot combustion air from the burner 3 is sucked into the ventilation passage 1c through the exhaust port 4a and is discharged to the outside from the hot air outlet 1b together with the indoor air. I did it like that.

Further, in the gas supply path 5 to the burner 3, a first solenoid valve 6 on the upstream side, a second solenoid valve 7 on the downstream side, and a governor 8 thereof are interposed, and the gas supply path 5 is connected in parallel to the second solenoid valve 7. A side passage 9 is provided, and when the temperature falls below a set temperature depending on the room temperature, the second solenoid valve 7 is opened to cause the burner 3 to burn in a so-called strong combustion state in which a large amount of gas is supplied to the burner 3. , when the temperature exceeds the set temperature, the second solenoid valve 7 is closed and the side passage 9 is closed.
The burner 3 is combusted in a so-called weak combustion state in which the amount of gas supplied to the burner 3 is small by supplying gas through the Stopping the gas supply 3
It is now possible to perform stage switching control.

In the drawing, reference numeral 10 indicates a gas tank, and reference numerals 11 and 12 indicate a pilot burner and a flame detection element for an oxygen deficiency safety device.

As shown in FIG. 3, the rotation speed of the convection fan 2 is controlled by a rotation speed control circuit 13 that switches the rotation speed into three stages: large, medium, and small.
Reference numerals 13a, 13b, and 13c indicate resistances for setting the convection fan 2 to strong, medium, and weak levels, which are intervened in the control circuit 13, and the resistances 13a, 13b, and 13c are thermocouples that are temperature-sensitive elements facing the burner 3. relay Rx, which is selectively energized according to the magnitude of the output from 14;
Ry's relay contacts rx and ry were selected to rotate at a predetermined rotation speed by opening and closing the contacts rx and ry.

To explain this further, the control circuit 13 inputs the output from the thermocouple 14 in the form of voltage to each positive input terminal of the two comparators 15 and 16,
When a voltage greater than the voltage value set by the resistor 17, 18 connected to the negative input terminal of each comparator 15, 16 is obtained at the positive input terminal of each comparator 15, 16, each comparator 15, 16 When an output is generated in each comparator 15, 16, each transistor Tx, Ty, which is a switching element connected in series with the relay Rx, Ry, is turned on, and the relay Rx, Ry is energized. This allows each contact rx and ry to be switched.

Here, in the present invention, the rotation speed control circuit 13 of the convection fan 2 is configured with a circuit 19 on the combustion side of the burner 3 and a circuit 20 on the combustion stop side of the burner 3. In addition, a bimetallic switch 21, which is a second switch, is inserted into the circuit 20 on the combustion stop side of the burner 3. Specifically, the first switch is connected to the contact ry of the relay Ry. A bimetallic switch 21, which is provided in the warm air heater body 1 and closes at 60°C and opens at 48°C, is connected in series to the resistor 13c that sets the convection fan 2 to a weak rotation.

In FIG. 3, 22 is an AC power supply, 23 is a power switch, 24 is a rectifier, 25 is a motor for the convection fan 2, and 26 is an amplifier circuit for amplifying the output from the thermocouple 14, that is, the thermoelectromotive force.

Next, to explain its operation, the output from the thermocouple 14 is small for 2 to 3 seconds after ignition of the burner 3, and the rotation speed control circuit 13 is on the side when combustion of the burner 3 is stopped as shown in FIG. The bimetal switch 21 is open because the temperature inside the hot air heater body 1 is less than 60° C., the convection fan 2 does not rotate, and cold air is prevented from blowing out.

If the room temperature is below the set temperature after 2 to 3 seconds have elapsed, the burner 3 will burn in a strong combustion state as described above. For this reason, the output of the thermocouple 14 also increases, producing an output in both comparators 15 and 16, and each relay Rx, Ry
is excited, the contacts rx and ry are switched, and the resistor 13a for setting strong rotation is selected. At this time, the rotation speed control circuit 13 is switched to the combustion side circuit 19 of the burner 3 as shown in FIG. 4, and the convection fan 2 is rotated strongly to heat the room. At this time, the bimetal switch 21 is closed, but does not affect the rotation of the convection fan 2.

When the room temperature exceeds the set temperature, the burner 3 burns in a weak combustion state as described above. Therefore, the output of the thermocouple 14 also decreases, and an output is generated only from the comparator 16, so that the relay Rx is demagnetized and its contact rx
returns to the normally closed side. In this case, the rotation speed control circuit 13 becomes as shown in FIG. 5, and the convection fan 2 rotates at a medium speed.

If the room temperature still rises, combustion in the burner 3 is stopped as described above. Therefore, the output from the thermocouple 14 becomes smaller, and no output is generated from the comparator 16 either, so the relay Ry is demagnetized and its contact ry returns to the normally closed state. In this case, the rotation speed control circuit 13 is switched to the circuit 20 on the burner 3 combustion stop side as shown in FIG. It is closed, and the convection fan 2 rotates slightly to blow out residual heat.

When the room temperature further decreases, the solenoid valves 6 and 7 open sequentially in response to this, the combustion of the burner 3 increases, the rotation speed of the convection fan 2 also increases, and the hot air heater is set. Operated at temperature.

When the first solenoid valve 6 is closed to extinguish the fire, the burner 3
combustion has finished, but the bimetal switch 21 remains closed until the temperature inside the hot air heater body 1 falls below 48°C, and during that time the convection fan 2 rotates weakly to blow out residual heat, causing the hot air heater to burn out. Overheating of the main body 1 is prevented.

In the above embodiment, the rotational speed of the convection fan 2 and the combustion amount of the burner 3 are switched and controlled in stages, but they may be controlled proportionally.

Further, in the above embodiment, the rotation speed of the convection fan 2 is changed by changing the resistors 13a, 13b, and 13c, but it may also be done by changing the tap voltage of the transformer 26, as shown in FIG. good.

Furthermore, in the case of the above embodiment, the number of first switches is reduced by one compared to that of the conventional example;
The number of comparators and transistors can also be reduced by one, which has the effect of further simplifying the overall circuit configuration.

(Effects of the Invention) According to the present invention, the rotation speed control circuit of the convection fan is configured with a circuit on the burner combustion side and a circuit on the burner combustion stop side, and both circuits are sensed. In addition to switching by the first switch that is linked to the output from the thermal element, the second switch, a bimetal switch, is inserted in the burner's combustion stop circuit, so that the first switch activates the rotation speed control circuit early. The number of switching functions can be made smaller than the number of rotational speed changes, and the overall circuit configuration is smaller than that of the conventional system, which is equal to the number of rotational speed changes. This has the effect of making it simple.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional side view showing an example of the implementation of the present invention, Fig. 2 is a line diagram with a circuit added to the - line cross-sectional front view of Fig. 1, and Fig. 3 is a diagram showing an implementation of the rotation speed control circuit. 4 to 6 are operational explanatory diagrams of the circuit in FIG. 3, FIG. 7 is a circuit diagram showing the main parts of another embodiment of the present invention, and FIG. 8 is a conventional example. FIG. 1... Warm air heater body, 2... Convection fan, 3
... Burner, 13 ... Rotation speed control circuit, 14 ...
Thermocouple (temperature sensing element), 19... Burner combustion side circuit of the rotation speed control circuit, 20... Burner combustion stop side circuit of the rotation speed control circuit, 21... Bimetal switch (second switch ), rx, ry...Contact (first switch).

Claims (1)

[Claims] 1 The convection fan is driven by a first switch that is linked to the output from a temperature sensing element facing the burner, and the convection fan is stopped by a second switch, which is a bimetallic switch, in which the rotation of the convection fan is The numerical control circuit is composed of a circuit on the combustion side of the burner and a circuit on the combustion stop side of the burner, and both circuits are switched by the first switch, and a circuit on the combustion stop side of the burner. A control device for a convection fan in a warm air heater, which includes the bimetal switch in a circuit.