JPS5850202Y2 - Hot air generator - Google Patents

Description

[Detailed description of the invention] This invention uses a damper linked to the displacement of a bimetal to automatically adjust the air flow rate to a heating element made of a positive temperature coefficient thermistor, and controls the amount of heat generated to adjust the temperature. The invention relates to a hot air generator.

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, 21 is a main body case, and an air inlet 22 is provided on one side of the main body case, and an air outlet 23 is provided on the opposite side.

24 is a casing for forming an air flow passage between the suction port 22 and the outlet 23; 25 is a filter provided in the air flow passage near the suction port 22; 26;
27 is a blower for forming an air flow; 27 is a heating element made of a positive temperature coefficient thermistor having a honeycomb-shaped cavity provided in the air flow path and near the outlet 23; 28 is a heating element 27 and the above A damper is provided between the blower 26 and the damper to adjust the amount of air flowing to the heating element 27, and its angle can be continuously changed by rotating two rotating shafts using adjustment knobs (not shown). ing.

In the hot air generator configured as described above, when the blower 26 is rotated and a current is applied to the heating element 27, air is sucked through the suction port 22, dust is removed by the filter 25, and the air is passed through the damper 28 to the heating element 27. When the air passes through the air, it is heated and hot air is blown out from the air outlet 23.

At this time, the angle of the damper 28 is manually changed so that the heating element 27
By changing the amount of air flowing through the heating element 27, the amount of heat generated by the heating element 27 will also change, making it possible to adjust the temperature.

However, in such a hot air generator, although the calorific value P(W) of the heating element 27 varies greatly depending on the amount of air Q (m3/m1n) passing through the heating element 27, as shown in an example in FIG. It only changes slightly depending on the temperature T1.

For example, when the air volume Q is 0.3 m3/min and the suction air temperature T1 is 20°C, the calorific value P (W) of the heating element 27 is 5th
From the figure, it is about 300W, and the suction air temperature T1 is 40℃.
When , the amount of heat generated by the heating element 27 P is 28 from FIG.
0W, and the amount of heat generated P decreases only slightly.

In order to greatly change the calorific value P of the heating element 27 according to changes in the intake air temperature T1 in this hot air generator, manually operate the adjustment knob and rotate the damper 28 about the rotation shaft 29 to 27 must be varied.

In other words, when the ambient temperature changes significantly, the adjustment knob must be manually operated in order to significantly change the amount of heat generated.

In addition, the hot air generator described above is used in a narrow closed space, such as a Yagura kotatsu, and the hot air supply device 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
Q heated by 0W heating element 27, 3 m3/mi
The air inside the tower is mixed and warmed by the n air.

Then, the air temperature inside the tower gradually rises, and the intake air temperature T1 of the hot air heating system also gradually rises.
As shown in the figure, although the calorific value P gradually decreases, the 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 blower. There is no choice but to take control to stop it.

In addition, among the heating devices often used in ordinary homes, infrared kotatsu, which heat small enclosed spaces, are equipped with a thermostat for temperature adjustment. The temperature inside the kotatsu is adjusted by converting it into electricity and repeating it repeatedly.

This method has the disadvantage that the temperature inside the kotatsu varies greatly, making the person trying to stay warm uncomfortable.

In addition, the thermostat etc. that adjust the temperature mentioned above is turned on and off.
When F is used, radio wave interference occurs, causing noise on televisions, radios, etc.

Furthermore, if a temperature controller such as a thermostat malfunctions,
The temperature inside the 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 generators,
It is a damper that can be used regardless of the volume of the space, whether it is open or a relatively narrow closed space, and controls the air flow rate to the heating element made of a positive temperature coefficient thermistor in response to the temperature of the air to be heated. The temperature of the air to be heated is quickly raised, and when the temperature exceeds a predetermined temperature, the airflow passage is closed with a predetermined gap, and the minimum amount of airflow is always sent to the heating element, allowing the heating element to dissipate heat and heating the heating element. It is an object of the present invention to eliminate the above-mentioned drawbacks by preventing the above-mentioned drawbacks and performing temperature control smoothly, reliably, and safely.

That is, the configuration of the present invention is that a heating element made of a positive temperature coefficient thermistor is disposed in the air flow passage of the blower, and the air flow rate in the air flow passage is adjusted in accordance with the temperature of the air to be heated in the air passage upstream of the heating element. A damper device is provided to control the heat generation amount of the heating element according to changes in air flow rate, and the damper is used to close the air flow passage with a predetermined gap when the heated air reaches a predetermined temperature or higher. This is a hot air generator with the following configuration.

First, the positive temperature coefficient thermistor receives a heat dissipation effect due to the passage of a large amount of air, so that the temperature does not rise, so due to its characteristics, the amount of heat generated is large.

Then, when the air temperature gradually increases, the damper is displaced in the direction of closing the air flow passage, reducing the amount of air flowing to the PTC thermistor, and reducing the amount of heat generated by the PTC thermistor.

The damper, at which the air to be heated reaches a predetermined temperature, has a predetermined gap and closes the air flow passage to send the minimum amount of airflow to the PTC thermistor, thereby preventing the PTC thermistor from overheating.

As mentioned above, the temperature of the heated air is quickly raised,
At temperatures above a predetermined temperature, overheating of the PTC thermistor is prevented.

The present invention will be described below with reference to an embodiment in which the present invention is incorporated into a Yagura Kotatsu as an example of a heater.

In FIG. 1, 1 is a tower, and 2 is a hot air generator installed under the top of the tower.

FIG. 2 is a longitudinal cross-sectional view of the warm air generator 2, in which 3 is the main body case, 4 is an airflow generation fan, 5 is a motor for driving the airflow generation fan 4, and 6 is for this drive. A motor fixing plate is attached to the main body case 3 via a plurality of anti-vibration rubbers 7 for fixing the motor, 8 is a fan casing which forms a fan outlet 9 together with the motor fixing plate, and 10 is the above-mentioned A blowout duct 11 forms a part of the air flow passage from the fan blowout port 9, and 11 is a heating element consisting of a positive temperature coefficient thermistor provided in this blowout duct I. This type of heating element has a ventilation hole, or is constructed by arranging a large number of flat plate, disk, etc. in an air flow, and has one or more of these heating elements.This heating element has positive characteristics. Since it consists of a 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, and when the air flow rate becomes extremely small, the amount of heat generated will also be extremely small. Become.

12 is an exhaust port provided in a removable intermediate duct 13 formed between the fan outlet 9 and the blower duct 10; A damper 15 automatically adjusts the air flow rate to the heating element 11 by dividing the flow, and mixes the airflow exhausted from the exhaust port 12 with the airflow blown out after passing through the heating element 11. A mixing chamber 16 is formed with a part of the wall surface of the blow-off duct 10, and the main body is a mixing duct that communicates with a main-body blow-off port 17 provided in the main body case 3, and 18 is a suction port provided in the main body case 3. .

FIG. 3 is an enlarged perspective view of the intermediate duct 13, with parts of the damper 14 and the exhaust port 12 cut away to show its structure in detail.

In this figure, 20 is a spiral-shaped bimetal whose outer peripheral end is fixed by a fixed shaft 23 and whose center is connected to the damper with a rotary shaft 21, which is displaced in proportion to the inflow air temperature, and when the temperature reaches a first predetermined temperature or higher. The damper 14 is rotated about the rotating shaft 21 in the direction in which the exhaust port 12 opens by applying a rotational force to the rotating shaft 21.

Reference numeral 22 designates the intermediate duct so that when the temperature of the incoming air exceeds a second predetermined value and the damper 14 is closed to eliminate the air flow to the heating element 11, the intermediate duct 13 and the damper 14 have a predetermined gap. This is a restraining plate provided in 13.

In the warm air electric kotatsu constructed as above,
At the start, the temperature inside the kotatsu is still low and the bimetal 20 is not deformed, so the damper 14 keeps the exhaust port 12 closed, and there is no flow of air exhausted from the exhaust port 12.
The flow rate of air blown out after passing through the heating element 11 is maximum, and at this time, the calorific value of the heating element 11 is at its maximum,
The temperature inside the kotatsu rises quickly, and because it is forced air, the temperature inside the kotatsu is even.

When the temperature inside the kotatsu exceeds a first predetermined temperature, the damper 14 rotates in proportion to the temperature in response to the displacement of the bimetal 20 in the direction of opening the exhaust port 12, and the flow rate of air exhausted from the exhaust port 12 is Conversely, the flow rate of air blown out through the heating element 11 decreases.

Both air flows are mixed in the mixing chamber 16 and the air flows through the main body outlet 17.
More blown out.

The amount of heat generated by the heating element 11 also decreases in proportion to the flow rate of air passing through it.

When the temperature rises to a second predetermined temperature, the damper 14 is positioned at a predetermined angle with respect to the fan outlet, and is brought into close contact with the restraint plate 23 provided on the intermediate duct 13 .
close the air flow to the heating element 11, and close the exhaust port 1.
The maximum flow rate of air is exhausted from the mixing chamber 16 and then blown out from the main body outlet 17.

In this state, the flow rate of air passing through the heating element 11 is minimal, so the amount of heat generated is extremely small.

When the temperature of the kotatsu falls, the damper 14 rotates in a direction to close the exhaust port 12, the flow rate of air passing through the heating element 11 increases, and the amount of heat generated increases.

However, since the heating element 11 is a positive temperature coefficient thermistor and is designed so that the flow rate of air passing through the heating element 11 decreases when the temperature increases, the heating element itself does not generate abnormal heat and is safe.

Also, even if the temperature inside the kotatsu drops due to people coming and going,
Accordingly, the damper 14 automatically adjusts the air flow rate and automatically increases the amount of heat generated, so that the temperature inside the kotatsu is always kept constant.

Also, since the damper always closes the intermediate duct with a predetermined gap, a constant amount of air flow always passes through the heating element, so the temperature of the heating element itself is much lower than when the air flow to the heating element is zero. As the temperature decreases, safety becomes even higher.

Furthermore, since the amount of heat generated is continuously and automatically adjusted, the temperature change inside the kotatsu is less than that of conventional infrared kotatsu, and does not cause discomfort to the person trying to stay warm.

Furthermore, since it does not have a temperature controller such as a thermostat that can be turned on and off, there is no radio wave interference to televisions, radios, etc. that occurs with conventional infrared kotatsu.

Moreover, the flow rate of air passing through the heating element is regulated by an exhaust port and a damper located between the fan and the heating element, so the amount of air generated by the fan is always constant, and the cooling effect of the fan motor is large, with due consideration given to the lifespan. It is designed with.

In addition, in the above embodiment, a restraint plate is provided inside the duct, but
A restraint plate is provided at a predetermined position of the damper or near the rotating shaft.

Alternatively, any structure may be used as long as the damper shape is larger than the exhaust port shape and smaller than the duct width, and a gap is formed in the duct side wall, so that a constant flow of air always passes through the heating element when the temperature reaches a predetermined temperature. .

The driving method of the damper is not limited to the spiral-shaped bimetal, and there are many methods such as configuring the damper itself with a bimetal.

Although there is an exhaust port between the fan and the heating element,
It may be of a structure in which the above-mentioned damper mechanism is provided at any position in the airflow passage without providing an exhaust port.

In this structure, the damper acts as a resistor in the air flow path and adjusts the air flow rate, so there is a drawback that the load on the fan fluctuates.

By the way, in the above description, the present invention was explained in the case of an electric kotatsu, but it goes without saying that it can also be used in other heaters and heat insulators.

As explained above, in this invention, air is supplied to the heating element of the PTC thermistor by forced air, so the temperature rises well and uniformly, and since the lowest air flow rate always passes through the heating element, the heating element itself The temperature is much lower than when the air flow rate is zero, making it even safer, and the structure is simpler than one that reduces the air flow rate to the heating element to zero, and the air flow rate is automatically adjusted by the damper. It is characterized by small temperature changes and no radio interference.

[Brief explanation of drawings]

The figures show one embodiment of the present invention. Figure 1 is a vertical cross-sectional view of the device installed in a Yagura Kotatsu, Figure 2 is an enlarged vertical cross-sectional view of the device, and Figure 3 is a view of the device installed with a damper. FIG. 4 is a longitudinal sectional view of a conventional hot air supply device; FIG. 5 is a characteristic diagram showing the amount of air passing through a heating element made of a positive temperature coefficient thermistor and the amount of heat generated; Figure 6 is a characteristic diagram of the kotatsu temperature and calorific value versus time when a conventional hot air generator is installed in the yagura kotatsu. In the figure, 4 is a fan, 8 is a casing, 10 is a blowout duct, 11 is a heating element, 12 is an exhaust port, 13 is an intermediate duct, 14 is a damper, 20 is a bimetal, and 22 is a restraint plate. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (1)

[Scope of utility model registration request] An air flow passage with a built-in fan for generating air flow and a positive temperature coefficient thermistor as a heating element, and an air flow passage provided in this air flow passage,
The air flow passage is displaced in accordance with the temperature of the incoming air, and automatically adjusts the air flow rate to the heating element, and when the temperature of the inflow air exceeds a predetermined value, the air flow passage has a predetermined gap between it and the air flow passage. A hot air generator characterized by comprising a damper that closes.