JPS5853258B2 - Hot air generator - Google Patents

Description

[Detailed Description of the Invention] This invention uses a positive temperature coefficient thermistor as a heating element,
The present invention relates to a hot air generator that generates hot air.

BACKGROUND ART Conventionally, there has been a hot air generator as shown in FIG. 4, for example, as described in Denshi Gijutsu Vol. 19, No. 2.

In this figure, 12 is a main body case, and an air suction port 13 is provided on one side of the main body case, and an air suction port 14 is provided on the opposite side.

15 is a casing for forming an air passage between the suction port 13 and the air outlet 14; 16 is a filter provided in the air passage near the suction port 13; and 11 is a casing for forming an air flow. A fan 18 is a heating element made of a positive temperature coefficient thermistor having a honeycomb-shaped cavity provided in the air passage and near the air outlet 14. A heating element 19 is provided between the heating element 18 and the fan 1γ. , an adjustment knob (
(not shown) rotates the rotating shaft 20, so that its angle can be changed continuously.

In the hot air generator configured as described above, when the fan 11 is rotated and a current is passed through the heating element 18, air is sucked through the suction port 13, dust is removed by the filter 16, and the air is passed through the damper 19 to the heating element 18. It is heated when passing through the air outlet 14.
Blows out warmer air.

At this time, by manually changing the angle of the damper 19 and changing the amount of air flowing through the heating element 18, the amount of heat generated by the heating element 18 will also change, making it possible to adjust the temperature.

In some temperature generators, the calorific value PH of the heating element 18 varies greatly depending on the amount of air Q (m2/m1n) passing through the heating element 18, as shown in Fig. 5, but it varies slightly depending on the intake air temperature TI. It just changes.

Also, the temperature T of the air blown from the outlet 14.

is approximately expressed by the following equation (1), To= 0.047 XP/Q +T 1 -(
1) For example, when the air volume Q is 0.3 m3/min and the suction air separation degree T0 is 20°C, the calorific value P of the heating element 18 (N is the fifth
From the figure, it is about 30o(w), and the blown air temperature To is 00 To=0.047X 10.3+20=67(C
).

In addition, in this hot air generator, when the intake air temperature T□ reaches 40°C, the calorific value P of the heating element 18 is determined from Fig. 5.
is 2801V) 1 min.The temperature of the blown air at that time T
.

is TQ=0.047X280/o, 3+40=84
CC) becomes larger.

In this warm air generator, even when the suction air temperature T□ is 40 (C), in order to lower the blowout air temperature To to 67 (T), in the same way as when the suction air temperature TI is 20 (T), the fifth From the figure, it is necessary to set the air amount Q to 0.5 m3/min or more, and the air amount must be changed by manually operating the adjustment knob.

In other words, if the ambient temperature changes, the adjustment knob must be manually operated in order to keep the blowing temperature constant, which is very troublesome.

Also, use the hot air generator described above in a narrow closed space, such as a Yagura kotatsu, and turn on the hot air generator from an atmosphere of 20°C.
t, the air temperature inside the Yagura Kotatsu has a calorific value P of 3.
The air inside the tower is mixed and warmed by the air at a rate of 0.3m3/min generated by the 00W heating element 18 at a rate of about 6'B:G)KM.Then, the air temperature inside the tower gradually rises and warm air is generated. Since the suction air temperature TI of the device also gradually increases, the calorific value P gradually decreases as shown in FIG. 6, but its change is small.

Therefore, the air temperature inside the tower increases rapidly, so in order to use this hot air generator as a Yagura Kotatsu, a temperature sensor is used to detect the air temperature inside the tower, and when the temperature exceeds a predetermined temperature, electricity is turned on to the heating element and fan. We have no choice but to control the aircraft to stop.

On the other hand, electric yagura kotatsu, which heat small enclosed spaces, use infrared lamps as heating elements.

A kotatsu using an infrared lamp uses high power from the time it starts up until a certain temperature, and when that temperature is exceeded (set temperature value), it changes to a small power and repeats this process to adjust the temperature inside the kotatsu. However, the disadvantage is that the temperature inside the Yagura Kotatsu varies greatly, making the person trying to stay warm uncomfortable.

In addition, the thermostat, etc. that adjust the temperature mentioned above is rONJ.
When rOFFJ, radio wave interference occurs and the TV,
This will cause noise on the radio, etc.

Furthermore, if a temperature controller such as a thermostat malfunctions,
The temperature inside the Yagura Kotatsu can become abnormally high, leading to the risk of fire.The purpose of this invention is to eliminate the drawbacks of conventional hot air heating devices, It is possible to blow out a fixed amount of air regardless of whether it is a relatively narrow closed space, and in a closed space, the amount of heat generated varies widely and automatically depending on the intake air temperature 1, that is, the air temperature in the closed space, and the blowout temperature is adjusted. In other words, the present invention provides a heating element consisting of an air flow generation fan and a positive temperature coefficient thermistor between the air flow passage and the air flow passage having an air flow path and an air flow outlet. and an opening located between the fan of the air flow path and the heating element, and by changing the flow rate of air to this opening in proportion to the temperature of the heated object. This hot air generating device is characterized by being equipped with a damper that automatically adjusts air circulation.

The present invention will be described below based on an example in which the present invention is incorporated into a yagura kotatsu as an example of a heater.

In Fig. 1, 1 is a tower, 2 is a casing provided under the top plate of this tower 1 and has an air flow passage 3 having intake and exhaust ports 3a+3b inside, and 4 is this air flow passage 3.
5 is a heating element consisting of a positive temperature coefficient thermistor disposed on the exhaust port 3b side of the air flow passage 3, which has a number of circular, rectangular, polygonal, etc. A large number of pores, a flat plate shape, a disk shape, etc. are arranged parallel to the air flow, and one or more of these are provided in the casing.

However, since the heating element of the lever consists of a positive temperature coefficient thermistor,
If the air flow rate passing through the heating element increases, the amount of heat generated will increase in proportion to it, and if the air flow rate decreases, the amount of heat generated will decrease.
When the air flow rate becomes extremely small, the amount of heat generated becomes extremely small.

Reference numeral 6 denotes an opening provided in the air flow path 3 between the fan 4 and the photothermal body 5, and is automatically opened and closed by the damper 1.

Note that the intake and exhaust ports 3a and 3b of the airflow passage 3 are opened in the wall surface of the casing 2.

FIG. 2 is an enlarged perspective view showing the structure of the damper γ in detail with a portion of the casing cut away.

9 is a shielding plate 8 whose outer end is fixed to the casing 2 and which changes in proportion to the temperature of the heated object, and whose inner end constitutes the damper γ.
It is a spiral-shaped bimetal fixed to the rotating shaft 11 of.

The bimetal 9 is designed to rotate the shielding plate 8 in the direction of opening the opening 6 at a rate of a certain angle relative to the temperature difference when the temperature of the air, which is the object to be heated, exceeds a predetermined temperature. When the temperature rises to a predetermined value, the shielding plate 8 closes the air flow path and minimizes the air flow to the heating element.

Reference numeral 11 denotes a frame-shaped gap closing plate that prevents airflow from leaking when the shielding plate 8 closes the airflow passage.

The gap closing plate 11, the shielding plate 8, and the bimetal 9 constitute the damper 1.

In the hot air kotatsu configured as described above, at the start, the temperature inside the kotatsu is still low, and the bimetal 9 is not deformed, so the shielding plate 8 does not rotate, and there is no flow of air exhausted from the opening 6, so the heating element The flow rate of air blown out through the heating element 5 is maximum, and the amount of heat generated by the heating element 5 is maximum, so the temperature inside the kotatsu rises rapidly, and since forced air is used, the internal temperature is also uniform.

When the temperature of the kotatsu gradually increases and exceeds a predetermined temperature, the shielding plate 8 gradually rotates, and the flow rate of air exhausted from the opening 6 increases in proportion to the temperature rise, and conversely, it passes through the heating element 5 and reaches the exhaust port. The amount of air blown out from 3b is reduced and the amount of heat generated is also reduced.

When the temperature inside the kotatsu falls, the shielding plate 8 becomes bimetallic 9.
As the heating element rotates in the opposite direction to the above as the amount of deformation decreases, the flow rate of air passing through the heating element increases, and the amount of heat generated increases.

However, since the heating element 5 is a thermistor with a positive temperature coefficient, it never overheats, and since it is designed so that the flow rate of air passing through the heating element 5 decreases when the temperature rises, the heating element itself does not generate abnormal heat. It's safe.

In addition, even if the temperature inside the kotatsu cools down due to people coming and going, the damper 1 adjusts the airflow force and automatically increases the amount of heat generated, so that the temperature inside the kotatsu is always maintained at a constant level. It has become.

Additionally, since the amount of heat generated is continuously and automatically adjusted, the temperature inside the kotatsu changes less than conventional infrared kotatsu, which causes less discomfort to those seeking warmth.

The characteristic graph in FIG. 3 shows temperature changes for the conventional infrared kotatsu b and the present invention kotatsu a when the load is constant.

Since it does not have a temperature controller such as a thermostat, there is no radio wave interference to televisions, radios, etc. that occurs with conventional infrared kotatsu.

Furthermore, since the air flow rate passing through the heating element 5 is controlled by the opening 6 and the damper 1 between the fan 4 and the heating element 5, the amount of air generated by the fan 4 is always constant, and the cooling effect of the fan motor is It is also large and has been designed with sufficient consideration to its lifespan.

Furthermore, since the bimetal is configured in a spiral shape, the driving mechanism of the shielding plate is small and can be easily configured. Similar effects can be obtained if the position is representative of the temperature of the heated object.

Further, although the tamper is composed of a shielding plate, a bimetal, and a gap closing plate, the shielding plate itself may be displaced according to the air flow temperature.

By the way, in the above description, this invention was explained in the case of an electric kotatsu, but it goes without saying that it can be used for other heaters.

As explained above, according to the present invention, a hot air generating device is provided with a heating element consisting of an air flow generating fan and a positive temperature coefficient thermistor in an air flow passage having an intake/exhaust port, and a heat generating element consisting of a fan in the air flow passage and a positive temperature coefficient thermistor. A damper is provided that automatically adjusts the air flow rate to the heating element by changing the air flow rate to this opening in proportion to the temperature of the heated object. With this structure, the hot air blowing temperature can be automatically maintained at a constant level regardless of the temperature of the intake air, and without the user having to perform troublesome hot air blowing temperature adjustments. It is possible to obtain a hot air generating device that can provide comfortable warmth to the user, is highly safe, and is easy to use.

Further, according to the present invention, the hot air blowing temperature can be adjusted without using a thermostat or the like as in the past, so that radio wave interference does not occur during the adjustment.

Furthermore, according to the present invention, since the load applied to the fan is constant when adjusting the hot air blowing temperature, there is an effect that the life of the fan can be extended.

[Brief explanation of the drawing]

Figures 1 to 3 show one embodiment of the present invention.
Figure 2 is a longitudinal sectional view, Figure 2 is an enlarged perspective view with a partial cutout of the casing where the damper is attached, and Figure 3 is a graph showing temperature changes over time when the load is constant.
Figure 4 is a vertical cross-sectional view of a conventional hot air generator, Figure 5 is a characteristic diagram showing the amount of air passing through a positive temperature coefficient thermistor heating element and the amount of heat generated, and Figure 6 is a conventional hot air generator installed in a kotatsu. This is a characteristic diagram of the temperature and calorific value of the kotatsu with respect to time when it is assembled. damper,
8 is a shielding plate, 9 is a spiral bimetal, and 10 is a rotating shaft. It should be noted that the middle or corresponding portion of each figure is shown.

Claims (1)

[Scope of Claims] 1. A heating element consisting of an airflow generation fan and a positive temperature coefficient thermistor is disposed between the intake and exhaust ports of an airflow passage having an intake and exhaust ports, and The air flow rate to the heating element is automatically controlled by an opening located between the fan and the heating element in the air flow path, and by changing the air flow rate to this opening in proportion to the temperature of the heated object. A hot air generator characterized by being provided with a damper that adjusts the temperature. 2. The hot air according to claim 1, characterized in that the damper is constituted by a spiral bimetal that is displaced according to the temperature of the heated object, and a shielding plate driven by the spiral bimetal. Generator. 3. The hot air generator according to claim 2, wherein the shielding plate has its rotating shaft fixed to the inner end of a spiral bimetal whose outer end is fixed.