JPH061123B2 - Hot air heater - Google Patents

Description

TECHNICAL FIELD The present invention relates to a hot air heater such as a fan heater.

2. Description of the Related Art Generally, as shown in FIG. 5, a hot air heater of this type is provided with a burner 3 and a combustion cylinder 4 inside a main body composed of an exterior 1 and a stand 2, and a convection motor 5 for feeding indoor air and convection. Fan 6,
It is provided with a filter 7 for protecting the convection fan 6 and removing dust in the air, and a louver 8 for discharging hot air into the room.

In the warm air heater having such a structure, the combustion heat A generated by the burner 3 and the combustion cylinder 4 is mixed with the indoor air B sent by the convection fan 6 rotated by the motor 5 to form the warm air C. It is sent indoors.

Problems to be Solved by the Invention However, in the above conventional hot air heater, when dust adheres to the filter 7, the amount of indoor air taken in through the filter 7 decreases and the temperature inside the main body rises abnormally. That is, it becomes overheated and dangerous. Further, in the case where a part of the room air from the convection fan 6 is used as the combustion air, the combustion failure occurs and carbon monoxide is generated in the room.

The present inventor has considered the following as a solution to such a problem. That is, a bimetal type thermostat 10 is provided on the blower guide plate 9 that forms a warm air passage, and when the air volume decreases due to dust and the hot air temperature rises abnormally, the thermostat 10 is operated to stop the operation of the entire circuit. Then, the combustion system is stopped and the decrease in the air flow due to dust is notified.

However, a malfunction may occur when only the warm air temperature is detected by the thermostat 10 as described above. That is, when the indoor temperature gradually rises as the heating continues, the temperature of the indoor air B itself rises, so that the indoor air amount that enters through the filter 7 is a normal amount even though the indoor air amount is normal. The warm air temperature corresponding to the temperature rise of the air B itself,
That is, the temperature of the thermostat 10 rises and the filter 7 malfunctions in the same manner as dust adheres to the filter 7. And if the alarm is only issued by detecting the temperature of the thermostat 10, it is a mere malfunction, but if the combustion is stopped together with this alarm, the combustion is often stopped, which is inconvenient. It becomes a thing.

The present invention has solved such a problem, and an object thereof is to enable accurate dust attachment detection without malfunction.

Means for Solving the Problems In order to achieve the above object, the present invention provides a temperature detecting element in a part of a hot air passage such as a blower guide plate and gives an alarm when the temperature detected by the temperature detecting element reaches a set temperature. Etc., and the set temperature is made variable according to the output from the room temperature detecting element.

Operation According to the present invention, as the indoor temperature rises, the set temperature for dust detection also rises accordingly, and accurate operation becomes possible.

EXAMPLE Hereinafter, an example of the present invention having a further improved safety will be described. In FIG. 1, 15 is an AC power supply, 16 is an operating switch, 17 is a fuel pump of a combustor, a blower for combustion,
A load group such as a convection fan, 18 is a control circuit mainly composed of a microcomputer, and controls the load group 17 based on the output from the room temperature thermistor 19. This control circuit 18 applies the room temperature output correction from the room temperature thermistor 19 to the output from the temperature detecting element (thermistor) 21 for dust detection provided in the air guide plate (warm air passage) 9 shown in FIG. The load group 17 is controlled. Reference numeral 20 denotes a thermostat for ensuring safety, which is provided on the blower guide plate 9 like the temperature detecting element 10 for detecting dust, and mechanically cuts off the energization of the entire circuit. In FIG. 4, the same reference numerals as those in FIG. 5 indicate the same parts.

Next, the structure of the control circuit 18 will be described with reference to the flow chart of FIG.

First, when the operation switch 16 is closed, the thermostat 20
A voltage is applied to the control circuit 18 and the load group 17 through the control circuit 18, and the entire operation is started by the control circuit 18 including a microcomputer.

The room temperature thermistor 19 constantly detects room temperature and compares the difference between this value and the desired set temperature. This difference determines the combustion amount of the burner and shifts to combustion. Further, the rotation speed of the convection motor 5 suitable for this combustion amount is also determined. When operating in this manner, the temperature detecting element 21 monitors the temperature of the blow guide plate 9. In this case, the temperature of the air guide plate 9 is determined by the temperature of the indoor air B sent by the convection fan 6 and the temperature of the combustion heat A. Therefore, since this temperature is constantly monitored by the temperature detecting element 21 and the thermostat 20, if the temperature detecting element 21 or the reference temperature is set to 90 ° C., it is checked whether or not this temperature is reached.
If the temperature is 90 ° C or lower, combustion, ventilation, temperature and detection are continued.

Since this reference temperature is greatly affected by the room temperature, the reference room temperature is corrected. This correction is stored in advance in the temperature correction unit 18a incorporated in the microcomputer of the control circuit 18. That is, the degree of correction of the reference temperature of the room temperature thermistor 19 is shown in FIG. 4, and the microcomputer is configured to set the temperature to 80 ° C. when the room temperature is 0 ° C., 90 ° C. when the room temperature is 20 ° C., and 95 ° C. when the room temperature is 30 ° C. I remember it. That is, when the room temperature is 0 ° C, the reference temperature is 80
When the temperature is 30 ° C, the temperature is 95 ° C.

After performing the temperature correction as described above, when the temperature is higher than the reference temperature as compared with the reference temperature, dust adheres to the filter 7 and the air volume is reduced. Therefore, an alarm is issued to the user by a lamp or a buzzer. In the case of less than this, continue combustion and ventilation.

Next, after the alarm is issued, the thermostat 20 monitors whether or not the cleaning is to be performed to see if the temperature is equal to or higher than the second reference temperature. The second reference temperature may be exactly the same as or higher than the reference temperature. If the temperature is lower than the second reference temperature, the combustion is further continued, and if it is higher than the second reference temperature, the combustion is stopped to improve safety. In this case, the entire circuit is stopped by the thermostat 20 instead of the control circuit 18 mainly composed of the microcomputer.

Although the entire circuit may be stopped by the control circuit 18 mainly composed of the microcomputer, malfunction due to runaway of the microcomputer may be considered. Therefore, the entire circuit should be stopped by mechanical means instead of electrical means. It is safe.

EFFECTS OF THE INVENTION As described above, the warm air heater of the present invention can prevent abnormal temperature rise inside the main body due to dust attachment and combustion failure due to lack of air in advance, and detection of dust attachment depends on the increase in indoor temperature. It can be performed accurately and surely without being operated, and it is easy to use without malfunction.

[Brief description of drawings]

FIG. 1 is a circuit diagram of a hot air heater according to an embodiment of the present invention, and FIG. 2 is a flow chart for explaining its operation, and FIG.
FIG. 4 is a graph showing temperature correction of the reference temperature, FIG. 4 is a sectional view of a warm air heater, and FIG. 5 is a sectional view of a conventional warm air heater. 6 ... Convection fan, 9 ... Warm air passage (blower guide plate),
21 ... Temperature detecting element, 18 ... Control circuit, 18a ...
Temperature correction part, 19 ... Room temperature thermistor, 20 ... Thermostat.

Claims (1)

[Claims] 1. A warm air heater for controlling a combustion amount and a convection fan according to an output from a room temperature thermistor, wherein a temperature detecting element is provided in a part of a warm air passage of the warm air heater, and a temperature detecting element is provided. A warm air heater having a temperature correction unit for correcting an operating temperature of the control circuit according to an output from a room temperature thermistor in a control circuit for issuing an alarm or stopping combustion based on an output from a detection element.