KR100189465B1 - Hot air heater - Google Patents

Abstract

1. TECHNICAL FIELD OF THE INVENTION

The present invention relates to a warm air heater.

2. The technical problem to be solved by the invention

The present invention can solve the problem of insufficient air supply while suppressing the temperature rise of the rotary shaft 9 of the convection blower 3, and can always perform a good combustion, and can prevent overheating of the main body case 1. It is an object to provide a warm air heater.

3. Summary of Solution of the Invention

A main body case (1) having a hot air blower outlet (2) and a convection blower (3), an air passage forming body (4) installed in the body case (1), and an upper portion installed in the air passage forming body (4) is opened. 11A, 11a provided between the combustion cylinder 6 and the burner 5 installed in the lower part of this combustion cylinder 6, and the combustion cylinder 6 and the top of the air passage forming body 4B. And the rear parts of the heat shield plates 11A and 11a extend downward to the edges and blow air from the convection blower 3 described above to the opening of the combustion cylinder 6 and the heat shield plates 11A, ( It is a warm air conditioner provided with the air volume distribution boards 11A and 11a which distribute and blow between 11a) and between heat shielding plates 11A and 11a and the top of the air path forming body 4B. .

4. Important uses of the invention

The present invention relates to a petroleum fan heater, gas fan heater and the like.

Description

Hot air heater

1 is an explanatory diagram showing the overall configuration of a warm air conditioner showing an embodiment of the present invention

2 is a longitudinal cross-sectional view of the main part

3 is a perspective view of the heat shield plate from an oblique angle from the rear

4 is a perspective view of the other heat shield plate obliquely viewed from the rear

5 is an explanatory diagram showing an enlarged main part of the burner.

6 is an explanatory diagram showing an enlarged main part of the vaporization container

* Explanation of symbols for main parts of the drawings

1: main body case 2: warm air outlet

3: convection blower 4: wind path forming body

4B: top of air passage forming body 5: burner

6: combustion cylinder 7: upper opening

8: pangaido 9: rotating shaft

10, 10a: heat shield plate 11A, 11a: air volume distribution plate

11B: L-shaped member 12, 12a: Vent (vent)

The present invention relates to hot air heaters, such as petroleum fan heater, gas fan heater.

Conventionally, this type of hot air heater is provided with a wind tunnel (path forming body) in a main body case having a hot air outlet and a convection blower, for example, as disclosed in Japanese Unexamined Patent Application Publication No. 1-20511. In the air passage forming body, a combustion cylinder having an open upper portion is provided, and a heat shield plate is provided between the combustion cylinder and the top of the air passage forming body, so that the combustion gas flowing out from the opening of the combustion cylinder portion and the air flow from the convection blower can be removed. The mixture is mixed in the air passage forming body, and the warm air is blown into the room from the hot air blowing outlet to be heated. The heat shield plate guides a part of the wind of the convection blower to the vicinity of the top of the air passage forming body, cools the top of the air passage forming body, and suppresses the temperature rise above the main body case.

By the way, in recent years, although the above-mentioned hot air heater is required to be downsized, when it is intended to be downsized, the combustion cylinder and the convection blower must be brought close to each other. There has been a problem that the temperature becomes high, the lubricating oil of the bearing portion evaporates or hardens, and the rotating shaft does not rotate smoothly.

Here, in the related art, the rotating shaft is prevented from abnormally high temperature by arranging a protective plate from the rear edge of the heat shield plate to cover the front of the convection blower.

However, if the protection plate covers the front of the convection blower, fresh air cannot be introduced into the opening of the combustion cylinder, and the burner flame is reduced due to insufficient air supply of the blower blower due to clogging of the filter. When the flame extends long and the flame flows out from the development part of the combustion cylinder, the flame cannot be made into a short flame, and there is a problem that the flame goes out from the hot air outlet or the amount of carbon monoxide generated increases.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described fact, and while suppressing the temperature rise of the rotating shaft of the convection blower, it is possible to solve the problem of insufficient air supply and to always perform good combustion, and to prevent overheating of the main body case. It is an object to provide a warm air heater.

As a result of earnestly examining in order to solve the above-mentioned problems, the present invention provides a heat shielding plate so that air blown from the convection blower is appropriately distributed between the opening of the combustion cylinder and the heat shield plate, and between the heat shield plate and the top of the air path forming body. By installing the air volume distribution plate extending downward in the rear edge of the present invention was found to be able to solve the above problems to complete the present invention.

The invention of claim 1 of the present invention is a main body case having a hot air outlet and a convection blower, an air passage forming body provided in the main body case, a combustion tube having an upper portion provided in the air passage forming body, and The burner installed in the lower part and the heat shield plate provided between the combustion cylinder and the top part of the air path forming body are provided, The rear part of this heat shield plate extends downward to the edge, and the air blown from the said convection blower is opened to the combustion cylinder. It is a hot air heater, characterized in that the air volume distribution plate for distributing and blowing between the portion and the heat shield plate, and between the heat shield panel wind path forming body top.

According to a second aspect of the present invention, in the warm air heater of claim 1, the gap (L1) between the open top end of the combustion cylinder and the lower end of the air flow rate distribution plate, the open top of the combustion cylinder, and the rotary shaft of the convection blower described above. The space | interval L2 and the ratio of the space | interval L3 of the upper part of an open part of a combustion cylinder, and the said heat shield board are L1: L2: L3 = 1: (1.5-2.5) :( 3.0-4.0), It is characterized by the above-mentioned.

According to a third aspect of the present invention, in the warm air heater of claim 1 or 2, the air volume distribution plate has a lower end in a corner of a rear edge of the heat shield plate on the side where more air from the convection blower is blown. It characterized in that it has an L (L) shaped member installed to extend to the vicinity of the rotation axis of the convection blower.

According to a fourth aspect of the present invention, in the warm air heater of claim 1 or 2, the air volume distribution plate is provided with the lower end extending downward from the rotation axis of the convection blower, and at the same time, It is characterized by providing a vent located above the opening of the combustion cylinder.

According to a fifth aspect of the present invention, in the warm air heater of claim 1 or 2, the air volume distribution plate is formed integrally with the heat shield plate.

When configured as in Claim 1, the rotary shaft does not become overheated by the radiant heat from the combustion cylinder, the temperature rise of the rotary shaft can be suppressed, and the damage caused by the temperature rise of the rotary shaft can be eliminated. In addition, even when the air supply is insufficient due to clogging of the filter, the burner's flame is reddened, and when it is extended and flows out from the opening of the combustion cylinder, it is blown from the convection blower by the action of the air volume distribution plate. Since air is blown by being distributed between the opening of the combustion cylinder and the heat shield plate, and between the heat shield plate and the top of the air path forming body, the spilled flame can be shortened as fresh air, and the flame does not go out from the hot air outlet. At the same time, it is possible to suppress a sudden increase in carbon monoxide generated when the air supply is insufficient and to stably burn the combustion body, and to prevent the body case from overheating.

According to the second aspect, it is possible to solve the problem of insufficient air supply while suppressing the temperature rise of the rotating shaft and to perform the combustion again and to prevent the overheating of the main body case.

This ratio is L1: L2: L3 = 1: (1.5 to 2.5): (3.0 to 4.0), preferably the ratio is L1: L2: L3 = 1: (1.7 to 2.3): (3.2 to 3.8), particularly preferred. Preferably, the ratio is L1: L2: L3 = 1: (1.8 ~ 2.1): (3.3 ~ 3.5). If L2 is less than 1.5, since the propeller fan falls between the upper end of the open end of the combustion cylinder and the lower end of the air volume distribution plate, it is not preferable because the amount of air blown to the opening of the combustion cylinder is too small. On the contrary, when L2 exceeds 2.5, since the propeller fan is close between the upper end of the open end of the combustion cylinder and the lower end of the air flow rate distribution plate, the amount of air blown to the opening of the combustion cylinder becomes excessively large. If L3 is less than 3.0, the amount of air blown between the heat shield plate and the top of the air passage forming body increases, and the amount of air blown to the opening portion of the combustion cylinder decreases. If L3 exceeds 4.0, the amount of air blows between the heat shield plate and the top of the air path forming body, and the main body case will overheat.

The configuration as claimed in claim 3 can simplify the configuration and improve the distribution of the air flow amount from the convection blower, thereby easily suppressing the temperature rise of the rotating shaft and solving the problem of insufficient air supply. Good combustion can be performed and overheating of the main body case can be prevented.

According to the fourth aspect, since the front of the rotary shaft of the convection blower is covered by the air volume distribution plate, the rotary shaft is not directly heated by the radiant heat from the combustion cylinder, and the temperature rise of the rotary shaft can be suppressed. It can eliminate the damage caused by the temperature rise. In addition, if the air supply is insufficient due to clogging of the filter, the burner's flame is reddened, and even if it extends long and flows out from the opening of the combustion cylinder, fresh air from the convection blower is vented through the vented flame. Since it is possible to supply the flames, the spilled flames can be shortened as fresh air so that the flames do not go out from the hot air outlet, and stable combustion can be carried out while suppressing the sudden increase of carbon monoxide generated when the air supply is insufficient. In addition, the main body case can be prevented from overheating.

When configured as in claim 5, the number of parts can be reduced and the simplification can be achieved.

EXAMPLE

Next, the present invention will be described in detail again with reference to Examples, but the present invention is not limited thereto.

Next, an embodiment of the present invention will be described based on FIGS. 1 to 6.

1 is an explanatory diagram showing the overall configuration of a warm air heater showing an embodiment of the present invention.

2 is a longitudinal cross-sectional view of the main portion thereof.

1 to 2, box (1) is a box-shaped body case having a hot air outlet (2) in the lower part of the front and a convection blower (3) in the rear part. The air passage forming body 4 whose one end is connected to the above-mentioned hot air jet port 2 and the other end is connected to the said convection blower 3 in succession is arrange | positioned. Arrows indicate the flow of air.

(5) is a burner which vaporizes and burns petroleum fuel disposed in the lower part of the main body case (1), and this burner (5) is attached to the vaporization cylinder (5A) and the upper portion of the vaporization cylinder (5A). The burner head 5B, the burner case 5C surrounding the periphery of the vaporization cylinder 5A, and the combustion secondary air in the burner case 5C are supplied to the burner head 5A. It consists of the combustion blower 5D which supplies a combustion primary air. In addition, the inlet port 5R of the combustion blower 5D described above is located outside the main body case 1, and a filter (not shown) is provided at the inlet port. 5E is an electric motor for the combustion blower 5D, 5F is a photoelectric sensor having a light emitting part and a light receiving part for detecting the rotation speed of the rotating shaft of the motor 5E, and 5G is a combustion secondary air supply. (5H) is the combustion primary air supply furnace, (5I) is a nozzle for supplying liquid fuel to the vaporization cylinder (5A), (5J) is the burner ring, (5K) is the flame of the burner head (5B) The heat recovery protrusion, 5M, provided opposite the hole is a frame sensor.

(6) is a combustion cylinder provided with an upper portion provided in the air passage forming body (4), and the combustion cylinder (6) covers the periphery of the upper portion of the burner (5). It is provided in the bottom face part 4A, and it is made to let a combustion gas outflow from the opening part 7 of the upper part.

The convection blower 3 is composed of an electric motor 3A fixed to a fan guard 8 for a filter and a propeller pen 3B attached to the rotary shaft 9, and a propeller fan 3B. Is opposed to the combustion cylinder 6 described above.

10 is a heat shield plate made of an aluminum plated steel sheet provided between the combustion cylinder 6 and the top portion 4B of the air passage forming body 4, and the heat shield plate 10 is inclined downwardly at its front and rear portions, respectively. The front part 10A and the rear inclination part 10B are formed, and as shown in FIG. 3, the heat shield plate 10 is provided at both ends of the front part 10A as shown in FIG. The fixing piece portion 10D having projections and screw holes for fixing to the plate is formed, and the heat shield plate 10 is formed by bending the left and right side portions at right angles downwards, respectively, to form the side piece portions 10C and 10C. Fixed side portions 10E, 10E, 10E, and 10E are formed on both sides of the side piece portions 10C and 10C, which are bent downwardly inclined, and the tip portions of these fixing piece portions 10E are formed in the above-described air path. It is inserted into the side wall of the sieve 4 and is fixed. The guide part 10F is being fixed by welding to the side piece part 10C which is not shown in figure.

At the rear edge of the gently inclined second half inclined portion 10B, an air flow distribution plate 11A extending downward is formed by bending and air from the convection blower 3 is formed. The L-shaped member 11B provided with the lower end extended to the rotation axis 9 of the convection blower 3 in the corner of the rear part edge of the heat shield plate 10 of the side which blows more is fixed by welding. . The airflow rate distribution plate 11 is constituted by the airflow rate distribution plate 11A and the elliptical member 11B.

An air vent 12 is formed between the lower end of the air volume distribution plate 11A and the upper end of the opening 7 of the combustion cylinder 6. 14 is an auxiliary heat shielding plate made of an aluminum plated steel sheet provided between the heat shielding plate 10 and the top portion 4B of the air passage forming body 4, and the auxiliary heat shielding plate 14 is formed of the air path forming body 4. The air from the convection blower 3 is introduced into the lower surface of the top portion 4B to further increase the cooling effect, and is fixed to the lower surface of the top portion 4B of the air passage forming body 4 by spot welding.

6A is a window provided in the front of the combustion cylinder 6. The window 6A is configured such that the mica plate 6C is brought into close contact with the outer surface of the combustion cylinder 6 by the fixing tool 6B.

The window transparent member for the window 6A is preferably one having heat resistance and sufficient strength. For example, when glass is used instead of the mica plate 6C, it is damaged by combustion heat or the like. If the mica plate 6C does not adhere to the outer surface of the combustion cylinder 6 and is not fixed, gaseous leaks from the interior of the combustion cylinder 6 and irrational points such as carbon monoxide are generated. Critical.

(F) shows the flame at the time of normal combustion, and (FX) shows the flame at the time of abnormal combustion due to lack of air supply.

In the above configuration, the distance L1 between the upper end of the open portion 7 of the combustion cylinder 6 and the lower end of the air volume distribution plate 11A is about 7 mm, and the upper end of the open portion 7 of the combustion cylinder 6 and the convection blower. The distance L2 between the rotation shaft 9 of (3) was about 13 mm, and the distance L3 between the upper portion of the opening 7 of the combustion cylinder 6 and the heat shield plate 10 was about 24 mm, so the ratio L1: L2: L3 = 1: about 1.9: about 3.4.

Further, the distance L4 between the lower end of the front portion 4C of the air passage forming body 4 and the upper end of the developing portion 7 of the combustion cylinder 6 is about 20 mm, and the internal diameter of the combustion cylinder 6 is about 156 mm, the air passage forming body. Height h1 from the bottom part 4A of (4) to the front-end | tip of the opening part 7 of the air passage forming body 4 is 150 mm, and the air path forming body 4 is formed from the bottom part 4A of the air path forming body 4. The height h2 to the top part 4B of was set to 215 mm.

In the above structure, the combustion gas by combustion of the burner 5 rises in the combustion cylinder 6, and the air path below the heat shield plate 10 through the upper opening 7 of the combustion cylinder 6. It discharges into the formation body 4, mixes with the wind sent from the convection blower 3 provided in the back part of the main body case 1, becomes hot air, it blows off from the hot air blower outlet 2, and heats the room.

The temperature rise of the rotating shaft can be suppressed by the air sent from the convection blower 3, and the air blown from the convection blower 3 by the action of the air flow rate distribution plate 11 opens the combustion cylinder 6; Since the air is properly distributed and blown between the portion 7 and the heat shield plate 10 and between the heat shield plate 10 and the top portion 4B of the air passage forming body 4, stable combustion can be performed and the main body case (1) can be prevented from overheating.

However, if the filter (not shown) installed in the inlet 5R of the combustion blower 5D is clogged by snow or curtain, or the like, the supply of combustion primary air in the vaporization cylinder 5A decreases. In short At this time, the flame F formed in the burner head 5B becomes a red flame, and extends as long as the flame FX shown by the imaginary line of FIG. 1 from the upper opening 7 of the combustion cylinder 6. Although part of the air blown from the convection blower 3 flows out, the upper opening 7 of the combustion cylinder 6 and the heat shield plate 10 are actuated by the air volume distribution plate 11 through the vent 12. Since the air is introduced into the space between the gas and the air, the fresh air is supplied at right angles to the flame FX flowing out from the upper opening 7, and the fresh air causes the flame FX to be accelerated to become a short flame. The flame does not go out from the hot air jet 2, and since carbon monoxide in the flame FX is accelerated in combustion to become carbon dioxide, generation of carbon monoxide can be reduced.

4 is an explanatory diagram showing another example of the heat shield plate used in the present invention.

The same code | symbol as the heat shield plate 10 shown in FIG. 3 shows the same thing. The heat shield plate 10a provided between the combustion cylinder 6 and the top portion 4B of the air passage forming body 4 has a lower end at its rear edge and a lower end of the rotation shaft 9 of the convection blower 3. An extended air volume distribution plate 11a is provided. The air flow rate distribution plate 11a is provided with an air vent 12a located above the opening 7 of the combustion cylinder 6. Although the vent part 12a was rectangular, the shape of a circle | round | yen, an ellipse, a triangle, etc. may be any.

In this configuration, since the front of the rotary shaft 9 of the convection blower 3 is covered by the air volume distribution plate 11a, the rotary shaft 9 is directly heated by radiant heat from the combustion cylinder 6. And the temperature rise of the rotary shaft 9 can be suppressed, and the lubricating oil of the bearing part evaporates or hardens by the temperature rise of the rotary shaft 9, and the rotary shaft 9 cannot rotate smoothly. Can be prevented. In addition, when the air supply shortage occurs due to a clogging of the filter, the flame of the burner 5 becomes a red flame, and when the flame is extended and flowed out from the upper opening 7 of the combustion cylinder 6, the flame is leaked. Since the fresh air from the convection blower 3 can be supplied to the FX through the vent 12a, the spilled flame can be made into a short flame as fresh air and the flame can go out from the hot air outlet 2 to the outside. In addition, it is possible to suppress a sudden increase in carbon monoxide generated in the absence of air supply.

In addition, in this embodiment, since the cutting parts 13 and 13 are formed in the upper end of the air volume distribution plate 11a, the heat of the heat shield plate 10a can be suppressed from being transmitted to the air volume distribution plate 11a. The temperature rise of the rotating shaft 9 can be suppressed further.

In the above embodiment, since the air volume distribution plates 11A and 11a are formed integrally with the heat shield plates 10 and 10a, the number of parts can be reduced and the configuration can be simplified.

5 is an explanatory view showing an enlarged main part of the burner 5 which can be preferably used in the present invention. The burner 5 is installed in the vaporization cylinder 5A, the burner head 5B attached to the upper portion of the vaporization cylinder 5A, and the outer circumference of the burner head 5B, and the burner head ( Blowing out from the flame hole of the burner head 5B and the burner ring 5J which has the comb-toothed annular wall which opposes the flame hole of 5B), and the several slit S was perforated toward the base part from the upper end part. And an ignition plug 5L for igniting the mixed gas and a frame sensor 5M, and insulator portions of the ignition plug 5L and the frame sensor 5M are provided outside the comb-shaped annular wall, In the comb-shaped annular wall, the insulator protection part 5P which has no slit S or has a slit shallower than another part in the part which opposes the insulator part of the spark plug 5L and the frame sensor 5M, ( 5Q) is formed. 5N is a siege heater for heating.

In this configuration, the flame formed in the flame hole during the combustion is small, and air flows into the comb-shaped annular wall from the slit S of the comb-shaped annular wall, so that it flows into the comb-shaped annular wall. The air accelerates the combustion reaction of the flame, provides good weak combustion with a small amount of mono-monoxide, and increases the flame formed in the flame hole during the combustion, and decompresses the heat of the flame. Therefore, the flame temperature decreases and the amount of NOx generated decreases. Moreover, since the insulator protection parts 5P and 5Q were formed in the comb-shaped annular wall which opposes the insulator part of the spark plug 5L and the frame sensor 5M, this insulator protection parts 5P and 5Q are made. It can accommodate the flame and direct the flow of flame at the same time, and there is no fear that the temperature of the insulator part of the spark plug 5L and the frame sensor 5M will rise above the heat resistance temperature and the spark plug 5L and the frame Thermal damage of the sensor 5M is reliably prevented by a simple configuration.

FIG. 6 is an explanatory view showing an enlarged main part of the vaporization cylinder 5A of the burner 5 which can be preferably used in the present invention. A plurality of heat recovery protrusions 5K are provided at the upper end of the cylindrical vaporization cylinder 5A having the bottom to which liquid fuel and combustion air are supplied, facing the flame hole of the burner head 5B. . 5N is a siege heater for heating.

In this configuration, since the flame is less during the combustion, and the flame approaches the flame hole portion of the burner head 5B, the upper ends of the burner head 5B and the gas cylinder 5A are approached by the flame in the approaching state. It heats sufficiently, and a vaporization part can be heated and maintained at the temperature suitable for vaporization of a fuel. On the other hand, the flame is increased during the combustion, and the hot portion of the flame falls from the flame hole, but a plurality of heat recovery protrusions 5K provided in the upper end of the vaporization barrel 5A are provided in the hot portion of the flame. Since the heat of the heat recovery protrusion 5K, which is contained and heated and heated to a high temperature, can be transferred to the vaporization unit, the amount of heat recovery at the time of steel combustion can be dramatically increased.

As shown in FIG. 6, these heat recovery protrusions 5K have a circumferential shape, the diameter T of which is set to about 6 to 8 mm and the height H of 8 to 10 mm, and are annular. It is provided with the space | interval s of the magnitude | size about 25-35 mm substantially equal to each other in the circumferential direction of the upper end part of the vaporizing cylinder 5A which is present, and is formed integrally with the vaporizing cylinder 5A again.

As described above, the temperature change range of the vaporization cylinder 5A can be reduced in a wide range from steel combustion to weak combustion, combustion is stabilized over a wide range from steel combustion to weak combustion, and the frame current is stabilized. At the same time, the amount of carbon monoxide generated is also reduced, and the nitrogen oxides can be reduced and the combustion range can be greatly expanded due to the decrease in the flame temperature caused by the heat recovery of the heat recovery protrusions 5K.

The hot air heater of claim 1 can remove the damage caused by the temperature rise of the rotating shaft, and the air blown from the convection blower by the action of the air volume distribution plate even when the air supply is insufficient due to the clogging of the filter. Air is distributed between the opening of the combustion cylinder and the heat shield plate, and between the heat shield plate and the top of the air path forming body, so that the spilled flame becomes fresh air and a short flame can prevent the flame from going out from the hot air outlet. At the same time, it is possible to suppress the sudden increase in carbon monoxide generated when the air supply is insufficient and to stably burn, and to prevent the body case from overheating.

The hot air heater of Claim 2 can solve the problem of lack of air supply while suppressing the temperature rise of a rotating shaft, and can perform favorable combustion again, and can prevent overheating of a main body case.

The warm air heater of claim 3 has a simple configuration, and since the distribution of the air flow rate from the convection blower is good, it is possible to solve the problem of insufficient air supply and to perform a good combustion again while easily suppressing the temperature rise of the rotating shaft. And overheating of the main body case is prevented.

In addition to the above effects, the warm air heater of claim 4 is covered with a wind volume distribution plate in front of the rotation shaft of the convection blower, so that the rotation shaft is not directly heated by radiant heat from the combustion cylinder, and the temperature rise of the rotation shaft can be suppressed. It is possible to eliminate the damage caused by the temperature rise of the rotating shaft.

In the warm air conditioner of claim 5, the number of parts can be reduced and the simplification can be achieved.

Claims (5)

(Correction) A main body case 1 having a hot air outlet 2 and a convection blower 3, an air passage forming body 4 provided in the main body case 1, and an inside of the air passage forming body 4 The burner 5 provided in the lower part of the combustion cylinder 6 with one upper part opened, and the heat shielding plates 10 and 10a provided between the combustion cylinder 6 and the top of the air passage forming body 4B. The rear portion of the heat shield plate 10, 10a extends downward to the edge of the heat shield plate, and the air blown from the convection blower 3 is blown through the opening of the combustion cylinder 6 and the heat shield plate 10, ( A warm air heater provided with air volume distribution plates 11A and 11a for distributing and blowing air between 10a and between the heat shield plates 10, 10a and the top of the air passage forming body 4B. . (Correction) The gap L1 between the open upper end of the combustion cylinder 6 and the lower ends of the air volume distribution plates 11A and 11a, and the open upper end of the combustion cylinder 6 and the above convection. The ratio of the interval L2 between the rotary shaft 9 of the blower 3 and the gap L3 between the open upper end of the combustion cylinder 6 and the above-described heat shield plates 10, 10a is L1: L2: L3 = 1: (1.5-2.5): (3.0-4.0) A warm air heater. (Correction) The heat shielding plate (10) according to claim 1 or 2, wherein the air volume distribution plates (11A) and (11a) are blown more air from the convection blower (3). A warm air heater, characterized in that the lower end portion has an L-shaped member (11B) installed in the corner of the rear edge of the convection blower (3) extending to the vicinity of the rotary shaft (9). (Correction) The air flow rate distribution plate according to claim 1 or 2, wherein the air volume distribution plates 11A and 11a are provided with their lower ends extending downward from the rotation shaft 9 of the convection blower 3 described above. A hot air heater, characterized in that vents (12) and (12a) located above the opening of the combustion cylinder (6) are provided in the distribution plates (11A) and (11a). (Correction) The warm air heater according to claim 1 or 2, wherein the air volume distribution plates (11A) and (11a) are integrally formed with the heat shield plates (10) and (10a).