JPS5853257B2 - Hot air heating device - Google Patents

Description

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

BACKGROUND ART Conventionally, there has been a hot air heating device as shown in, for example, FIG. 5, as described in Vol. 19, No. 2 of Electronic Technology.

In this figure, 9 is a main body case, and an air suction lower is provided on one side of the main body case, and an air outlet 8 is provided on the opposite side.

2 is a casing for forming an air passage between the suction lower and the air outlet 8; 10 is a filter provided in the air passage near the suction port I; 3 is a fan for forming an air flow. , 4 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 8; 6 is this heating element 4 and the fan 3;
The rotary shaft 11 is rotated by a damper for adjusting the amount of air flowing to the heating element 4 using an adjustment knob (not shown), and its angle can be changed continuously.

In the hot air heating device configured as described above, when the fan 3 is rotated and a current is passed through the heating element 4, air is sucked from the suction lower.
Dust is removed by a filter 10, and when the air passes through a heat generating element 4 via a damper 6, it is heated and hot air is blown out from an air outlet 8.

At this time, by manually changing the angle of the damper 6 and changing the amount of air flowing through the heating element 4, the amount of heat generated by the heating element 4 will also change, making it possible to adjust the temperature.

However, in such a hot air heating system, although the calorific value P(5) of the heating element 4 varies greatly depending on the amount of air Q (m/m1n) passing through the heating element 4 as shown in FIG. 6, the intake air temperature TI In some cases, it only changes slightly.

Also, the temperature T of the air blown out from the outlet 8.

is approximately expressed by the following equation (1), TQ=0.047XP/Q+TI ・−・−・・・
・-・-(1) For example, when the air volume Q is 0.3 m3/min and the suction air temperature TI is 20°C, the calorific value P of the heating element 4 is
% is about 300- from Figure 6, and the blown air temperature T
o is 'rQ=o, o 47X 30 o/ 0.3X20=
67CC).

In addition, in this hot air heating device, when the intake air temperature TI reaches 40°C, the calorific value P of the heating element 4 becomes 280 (w) as shown in Fig. 6, and the blowout air temperature To
is T□ =0.047X 28010.3+40=84(
'C) becomes larger.

In this hot air generator, even when the suction air temperature T□ is 40 cc), in order to lower the blown air temperature To to 67 (0) in the same way as when the suction air temperature T2 is 20 ℃, from Fig. 6, Air amount Q is 0.5 m”/min
or more, and the amount of air must be changed by manually operating an 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.

In addition, the hot air heating device described above is used in a narrow closed space, such as a Yagura kotatsu, and the hot air generator is turned on from an atmosphere of 20°C.
In this case, the air temperature inside the Yagura Kotatsu will have a calorific value P of 30
0,3 heated to approximately 67g by the 0W heating element 4
The air inside the tower is mixed and warmed by the air of m'/min.

Then, the air temperature inside the tower gradually rises, and the intake air temperature TI of the hot air heating device also gradually rises, so that although the calorific value P gradually decreases as shown in FIG. 7, 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. There is no choice but to take control to stop it.

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

A kotatsu using an infrared lamp uses a large amount of electricity from the time it starts up until a certain point, and when it exceeds that temperature (the set temperature value), it changes to a small amount of electricity and repeats this process to adjust the temperature inside the kotatsu.

This method had the disadvantage that the temperature inside the Yagura Kotatsu varied 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 may become abnormally high and there is a risk of a fire.

The purpose of this invention is to eliminate the drawbacks of conventional hot air heating devices,
To provide a hot air heating device that automatically changes the calorific value of a heating element according to the temperature of intake air without controlling ONJ and OFFJ of the heating element, thereby automatically adjusting the temperature of a heated object. It is.

That is, the present invention includes an air flow generation fan provided in an air flow passage having an inlet and an outlet, and a positive temperature coefficient thermistor as a heating element also provided in the air flow passage and near the outlet. an exhaust port provided in the air flow passage between the positive temperature coefficient thermistor and the fan; This hot air heating device is equipped with a flat damper made of bimetallic material that adjusts the amount of air flowing through the damper and the damper.

The details of this invention will be described below based on an example in which the invention is incorporated into a tower kotatsu.

In Fig. 1, 1 is a tower, 2 is a casing provided under the top of the tower and forms an air flow path, 3 is a fan that generates air flow in the air flow path formed by this casing, and 4 is a A heating element consisting of a positive temperature coefficient thermistor provided on the outlet side of the casing 2, which has a large number of circular, rectangular, polygonal, etc. ventilation holes, or has a large number of flat plate, disk, etc. airflow holes. These heating elements are arranged in parallel to each other, and one or several of these heating elements are provided inside the casing.

Furthermore, since the heating element consists of a positive characteristic thermistor, as the air flow rate passing through the heating element increases, the amount of heat generated increases proportionally, and as the air flow rate decreases, the amount of heat generated decreases, and the air flow rate becomes zero. Sometimes the amount of heat generated is minimal.

5 is an exhaust port provided between the fan 3 and the heat generating element 4 of the casing 2; 6 is provided in the exhaust port 5 and has one side fixed to the heat generating element to exhaust air flow to the heat generating element; A flat damper made of bimetal that automatically adjusts by diverting the flow to the port 5, 7 is the suction port provided at the front end of the casing, and 8 is the suction port provided at the rear end of the casing, and the damper passes through the heating element. This is an outlet from which hot air is blown out.

FIG. 2 is an enlarged perspective view showing the structure of the damper 6 made of bimetal and a portion of the exhaust port in detail, with a portion thereof cut away.

In the hot air yagura kotatsu constructed as described above, at the time of start, the temperature inside the kotatsu is still low and the damper 6 made of bimetal does not deform, so there is no flow of air exhausted from the exhaust port 5. The flow rate of air passing through the heating element 4 and blown out from the outlet 8 is the maximum, and the air flow rate passing through the heating element 4 is the maximum.
The amount of heat generated is at its maximum, the temperature inside the kotatsu rises quickly, and because the air is forced to blow, the internal temperature is also uniform.

As the temperature inside the kotatsu gradually rises, the damper 6 also deforms, and the flow rate of air exhausted from the exhaust port 5 increases in proportion to the temperature rise, and conversely, the air passes through the heating element 4 and is blown out from the air outlet 8 The flow rate decreases and the amount of heat generated also decreases.

If the temperature inside the kotatsu falls, the amount of deformation of the damper 6 will decrease, and the flow rate of air passing through the heating element 4 will increase.

However, since the heating element 4 is a thermistor with positive temperature characteristics, the current value decreases when the temperature rises, and it never overheats.Moreover, it is designed so that the flow rate of air passing through the heating element 4 decreases when the temperature rises. The heating element itself does not generate abnormal heat and is safe.

In addition, even if the temperature inside the kotatsu cools due to people coming and going, the damper 6 automatically adjusts the air flow rate and automatically increases the amount of heat generated to keep the temperature inside the kotatsu constant. It has a structure.

Additionally, since the amount of heat generated is continuously and automatically adjusted, the temperature change inside the kotatsu is smaller than that of conventional infrared kotatsu, which does not cause discomfort to those seeking warmth.

The characteristic graph in FIG. 3 shows the temperature change in the conventional infrared kotatsu and the kotatsu a of the present invention when the square load is constant.

Since it does not have a thermostat or other 10NJ/10FFJ temperature controller, there is no interference with radio waves to TVs, radios, etc. that occurred with conventional infrared kotatsu.

Furthermore, since the air flow rate passing through the heating element 4 is controlled by the exhaust port 5 and the damper 6 between the fan 3 and the heating element 4, the amount of air generated by the fan 3 is always constant, and the fan motor The cooling effect is also large, and the lifespan is also taken into consideration.

In the above embodiment, the damper 6 is made of a single bimetal composed of a flat plate, but the same operation can be expected even if this bimetal is not made of a single plate and a plurality of rectangular bimetals are provided in the same direction. .

Figure 4 shows a bimetal damper consisting of a single plate and b.
The damper is constructed by attaching two elongated bimetals at both ends, which are flexible, and are fitted with a material that prevents wind from passing through. In this case, the amount of bimetal material needed is small, so it can be manufactured at a low cost, and the bimetal deforms as the temperature rises without applying twisting force, which has the advantage of smoother deformation.

By the way, in the above explanation, the case where this invention is applied to a yagura kotatsu was explained, but it goes without saying that it can be used for other heaters.

As explained above, in this invention, air is supplied to the heating element of the PTC thermistor by forced air blowing, so the temperature rises quickly and uniformly, and it also uses a damper made of bimetal that detects and displaces the temperature of the heated object. Since the amount of air blown to the heating element is automatically adjusted, there are few temperature changes, providing comfortable warmth, and is highly safe and does not cause radio interference.

Furthermore, since the damper is made of bimetal itself, its structure is simplified and the number of parts is reduced, resulting in improved reliability.

[Brief explanation of the drawing]

Fig. 1 is a vertical cross-sectional view showing an embodiment of the present invention, Fig. 2 is an enlarged perspective view with a part cut away, mainly showing the casing portion to which the damper is attached, and Fig. 3 is the time when the load is constant. Figure 4 is an enlarged perspective view of a part of the damper, Figure 5 is a vertical cross-sectional view of a conventional hot air heating device, and Figure 6 is the amount of air passing through the PTC thermistor heating element and the amount of heat generated. FIG. 7 is a characteristic diagram of the temperature inside the kotatsu and the amount of heat generated with respect to time when a conventional hot air heating device is installed in a yagura kotatsu. In the figure, 2 is a fan, 3 is a casing, 4 is a heating element, 5 is an exhaust port, and 6 is a damper. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (1)

[Scope of Claims] 1. An air flow generating fan provided in an air flow passage having an inlet and an outlet, and a heating element provided in the air flow passage and on the outlet side of the fan. a positive temperature coefficient thermistor; an exhaust port provided in the air flow passage between the positive temperature coefficient thermistor and the fan; A hot air heating device comprising: a flat damper made of bimetal that adjusts the amount of air exhausted from the mouth and the amount of air flowing to the positive temperature coefficient thermistor. 2. The hot air heating device according to claim 1, characterized in that the damper is constructed of a rectangular shape whose longitudinal direction is aligned with the direction of air flow and whose short sides are fixed, and which is made of a single bimetallic piece. 3. The damper is constructed such that a plurality of rectangular bimetals are provided in the same direction, the longitudinal direction of the bimetals is aligned with the direction of air flow, and one short side of each bimetal is fixed. A hot air heating device according to scope 1.