JP2776177B2 - Hot air heater - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an open-air warm air heater.

[0002]

2. Description of the Related Art A conventional open-air type warm air heater provided with a bell mouth plate has a burner section 31 as shown in FIGS.
And a combustion cylinder 32 for guiding the combustion gas from the burner section 31;
The air from the convection blower 34 provided with the duct 33 and opposed to the combustion tube 32 is mixed with the combustion gas discharged from the combustion tube 32, and hot air is blown out from the air outlet 35 to blow the room. It is designed to heat. Here, a bell mouth plate 36 is attached to the rear portion of the duct 33, and a ventilation hole 37 is provided in a peripheral wall of the duct located behind the bell mouth plate 36. With this configuration, a convection air intake hole of the fan guard 38 is provided. Even if the opening area of 39 is small, the air inside the device main body can be taken in through the ventilation hole 37 of the duct 33, and even if dust adheres to the surface of the fan guard 38, the rate of reduction of the air volume is small, and the temperature inside the device main body is low. It is configured such that rise and the like can be prevented.

[0003]

However, in the above-mentioned conventional structure, the vent hole 37 provided at the rear of the bell mouth plate 36 is provided.
Is limited by the distance between the bell mouth plate 36 and the device exterior 40, and it has become impossible to sufficiently take in the air inside the device body. That is, at present, hot air heaters are becoming more compact and the design tends to be emphasized. Therefore, the space between the ducts 33 provided with the ventilation holes 37 becomes narrower, and the circulation of air in the equipment body is poor. Was becoming a trend.

As shown in FIG. 9, the bell mouth plate 36 is formed in a round shape 36a from the rear side of the apparatus main body, and a large dead space 41 is formed between the opening edge of the round shape 36a portion and the duct peripheral wall. There was a turbulent flow in this area, and the flow velocity was reduced, resulting in a decrease in the amount of air blown.

[0005] Therefore, in such a device configuration, when the dust in the room begins to adhere to the fan guard 38 when the device is started to be used, the rate of reduction in the amount of air blown by the convection blower 34 is large even though the amount of dust is not so large. In a short time, the exterior temperature of the device body rises, or incomplete combustion occurs in a type in which a part of the air from the convection blower 34 is used as a part of the combustion air. There was a problem of lack of reliability in terms of safety. And in those equipped with an overheat prevention device, this operates in a short time and the operation of the equipment automatically stops,
If the dust attached to the fan guard 38 is not removed frequently, the operation of the equipment cannot be continued,
There was a problem that the usability was poor.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has as its object to reduce the rate of decrease in the amount of air blown in a short time while reducing the size of the device body and improving the design.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a burner for performing combustion, a combustion tube provided so as to cover the burner, and a box-shaped cover provided so as to cover the burner and the combustion tube. A duct, and a convection blower attached to the back of the main body to supply air for warm air into the duct, wherein a fan of the convection blower is incorporated in the duct, and a duct facing the fan is provided. A configuration in which a bell mouth plate is provided at the rear portion, and a portion to be attached to the duct peripheral wall portion of the bell mouth plate is formed in a tapered shape, and a ventilation hole is provided in a duct peripheral wall portion facing the tapered portion of the bell mouth plate, Alternatively, the bell mouth plate is formed in a round shape on both the fan side and the side opposite to the fan, and the throat between the round portions is formed in a straight pipe shape .

[0008]

According to the present invention, the ventilation hole provided in the peripheral wall of the duct can be enlarged to the extent that it can face the tapered portion of the bell mouth plate even if the apparatus main body is made compact by the above structure. As a result, the air inside the aircraft can be sufficiently taken in. In addition, the air flow before and after the bell mouth, that is, at the inlet and the outlet, becomes smooth, and the amount of air supplied through the bell mouth plate increases accordingly. Therefore, even if the fan guard has a small opening area for the convection air intake hole and the dust easily adheres to the fan guard in a short time with a focus on design, the ventilation rate is lower than before. It can be kept small, and it is possible to prevent a rise in temperature inside the body of the machine.

[0009]

EXAMPLES (Example 1) Figure 1 Example 1 below or not a present invention will be described with reference to FIG. 1 and 2, reference numeral 1 denotes a main body having a hot air outlet 2 on the front surface, and 3 denotes a burner provided on a table 4 of the main body 1 via legs 5, and in this embodiment, vaporizes liquid fuel. Burners are used for combustion. Reference numeral 6 denotes a combustion tube that covers the upper side of the burner 3, and reference numeral 7 denotes a horseshoe-shaped duct provided in the main body so as to surround the combustion tube 6, and a bellmouth plate 8 is attached to the rear inside. The bell mouth plate 8 has a tapered portion 8a attached to the peripheral wall of the duct to secure a wide space for forming a ventilation hole, which will be described later. Reference numeral 9 denotes a convection blower for supplying air for warm air into the duct 7, which is attached to the back of the main body via a fan guard 10.

The convection blower 9 has a propeller fan 11 positioned in the duct 7 and opposed to the bell mouth plate 8. A large number of air intake holes 12 are formed on the rear surface and the entire peripheral surface of the fan guard 10. However, the size of the fan guard 10 has been reduced due to the recent downsizing of the device body, and the air intake holes 12 have been reduced. The total area of No. 12 tends to decrease. Numeral 13 denotes ventilation holes for compensating for the reduced air intake holes 12, which are formed in a large number on the peripheral wall of the duct behind the bell mouth plate 8, and the convection blower 9 also supplies air through the ventilation holes 13. Will be sucked. The ventilation hole 13 is formed in a wide space in which a portion to be attached to the duct peripheral wall of the bell mouth plate 8 is secured in a tapered shape 8a, and its size is opposed to the tapered portion as compared with the conventional one. It is bigger.

In the above configuration, first, a general operation as a hot air heater will be described. The combustion flame formed in the burner 3 is blown by the convection blower 9 to the fan guard 1.
The air obtained through the convection air intake hole 12 provided in the cylinder 0 and the air in the body obtained through the ventilation hole 13 provided in the peripheral wall of the duct behind the bellmouth plate are supplied to complete combustion flame.
The combustion tube 6 is heated by the combustion heat generated by the combustion flame, and the air sent from the convection blower 9 exchanges heat with the combustion tube 6 to be discharged into the room as warm air from the outlet 2 to heat the room. .

Here, the opening area of the convection air intake hole 12 of the fan guard 10 is small, and dust adheres to the fan guard 10 in a short time after the operation of the device, and the convection air intake hole 12
Even if most of them are closed, the ventilation holes 13 of the duct 7 are larger than the conventional ones, so that sufficient air can be taken in from the airframe, the rate of decrease in the amount of hot air due to dust adhesion can be reduced, and It is possible to prevent an excessive air volume reduction.

[0013] Thus, the apparatus having to utilize a portion of the air from the pair diverted air blower 9 as combustion air, combustion air quantity introduced into the combustion cylinder 6 by the air volume reduction due to dust adhesion of the fan guard 10 Is not reduced in a short time, and deterioration of exhaust gas performance such as generation of CO due to lack of air can be prevented as much as possible.

In addition, when the air volume is reduced, the external temperature of the equipment body does not abnormally rise in a short time, and the overheating prevention device 14 is provided above the duct 7 to cause an abnormal temperature rise. Even in the case of stopping the combustion to promote cleaning, the stop of the combustion due to a rise in temperature is reduced, and the trouble of frequently removing dust adhering to the fan guard 10 is eliminated. Driving can be continued.

Further, a tapered shape 8a in front of the bell mouth plate 8 is provided.
Has the effect of blocking the radiant heat from the high-temperature burner section and preventing the temperature rise of the body exterior.

(Embodiment 2) First, FIGS. 3 and 4 show another conventional reference example. This reference
In the example, the bell mouth plate 8 is not provided with the tapered shape 8a and the ventilation hole 13 is formed.
Is the same size as the conventional one, but the bell mouth plate 8 has a round shape on both the fan side and the side opposite to the fan.
b and 8c, and a throat portion 8d between both round portions is formed in a straight pipe shape.

According to this configuration, the wind from the convection blower 9 is efficiently taken in the bell mouth plate 8 while being rectified by the fan-shaped round shape 8b in the same manner as in the prior art, and the taken air is blown to the front side. The air flows smoothly forward along the round shape 8c, and there is little abrupt change in the flow path cross section. Therefore, the hot air flow rate of the down rate due to dust adhering to the fan guard 10, suppress the sudden air volume down
It is possible to control.

Further, both round shapes 8b and 8 of the bell mouth plate 8 are formed.
Since the throat portion 8d between c and c has a straight pipe shape, even if the positional relationship between the propeller fan 11 and the bellmouth plate 8 slightly changes due to component dimensions, assembly variations, and the like, it is possible to always secure a stable air flow. Therefore, even if dust adheres to the fan guard 10, the down rate of the amount of warm air can be suppressed .

FIGS. 5 and 6 show a second embodiment of the present invention .
In the second embodiment, the reference example shown in FIGS. 3 and 4 is further modified.
It is good. Ie, the duct 7 bell mouth plate 8 opposite to the tapered portion to form a tapered 8a
In together when larger forming the ventilation holes 13 in the peripheral wall, the fan side and the fan and round shape 8b any of opposite side of the bell mouth plate 8, formed in 8c, etc. of between two round shape portions moiety 8d has a straight tube configuration.

[0020] Therefore, according to this arrangement, FIG 3,
In addition to the basic effects of the reference example shown in FIG.
Therefore, the obtained effect is further added, and the down rate of the amount of warm air can be greatly reduced.

[0021]

As is apparent from the above description of the embodiments, the present invention can reduce the air volume due to the reduction of the area of the convection air intake hole of the fan guard while reducing the size of the equipment. And at the same time, it is possible to prevent abnormal overheating of the device in a short time. In addition, those that use part of the air taken in from the convection air intake hole as part of the combustion air can prevent incomplete combustion due to lack of air and have an overheat prevention device. It is easy to use, because it can prevent this from operating in a short time,
In addition, a highly safe and compact hot air heater with excellent dust resistance can be obtained.

[Brief description of the drawings]

FIG. 1 is a plan view of a hot air heater according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view of the hot air heater.

FIG. 3 is a cross-sectional view of a hot air heater according to a reference example .

FIG. 4 is an enlarged sectional view of a bellmouth plate of the hot air heater .

FIG. 5 is a plan view of a hot air heater in Embodiment 2 of the present invention .

FIG. 6 is a sectional view of the hot air heater .

FIG. 7 is a plan view of a conventional hot air heater.

FIG. 8 is a cross-sectional view of the hot air heater .

FIG. 9 is an enlarged sectional view of a bellmouth plate of the hot air heater .

[Explanation of symbols]

 Reference Signs List 3 burner 6 combustion cylinder 7 duct 8 bellmouth plate 8a tapered portion 8b rounded portion 8c rounded portion 8d throat 9 convection blower 11 fan 13 ventilation hole

────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-3-20564 (JP, A) JP-A-4-8900 (JP, A) JP-A-4-24470 (JP, A) JP-A-4-205 370399 (JP, A) Japanese Utility Model Showa 60-14453 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) F24H 9/06 302 F24H 9/02 302

Claims (2)

(57) [Claims] 1. A burner for performing combustion, a combustion tube provided so as to cover the burner, a box-shaped duct provided so as to cover the burner and the combustion tube, and air for warm air is supplied into the duct. A convection blower attached to the back of the main body, a fan of the convection blower is incorporated in the duct, and a bellmouth plate is provided at a rear portion of the duct facing the fan, and a duct peripheral wall of the bellmouth plate is provided. A hot air heater in which a portion to be attached to the portion is formed in a tapered shape and a ventilation hole is provided in a peripheral wall of a duct facing the tapered portion of the bell mouth plate. 2. A burner for performing combustion, a combustion cylinder provided so as to cover the burner, a box-shaped duct provided so as to cover the burner and the combustion cylinder, and supplying hot air to the duct. A convection blower mounted on the back of the main body, and a fan of the convection blower is incorporated in the duct, and a bell mouth plate is provided at a rear portion of the duct facing the fan, and a duct peripheral wall of the bell mouth plate is provided. The bell mouth plate has a ventilation hole formed on the peripheral wall of the duct facing the tapered portion of the bell mouth plate, and the bell mouth plate is rounded on both the fan side and the side opposite to the fan. warm-air heating machines for etc. part of which was a straight pipe shape between both rounded-shaped portion so as to form a Jo.