CN108730977A - Burner apparatus - Google Patents

Abstract

The present invention provides a burner device capable of improving flame retention with a simple structure. The side plate part (61) of the burner device (B) forms an opening for taking in air (91) and an opening for taking in air (92). The part (92) can make the first gap (81) between the side plate part (61) and the side wall part (18) of the burner housing (1) from the air flow path (59) and the air flow path (40a). ) part of the supplied air flows into the second gap (82) between the side plate portion (61) and the endmost burner body (3A).

Description

Burner device

technical field

The present invention relates to a burner device suitable for use as a constituent element of a gas hot water supply device and the like.

Background technique

As specific examples of the burner device, there are burner devices described in Patent Document 1 and Patent Document 2.

The burner devices described in these documents are arranged in a row with a plurality of burner bodies (gas combustion tubes) and housed in a burner case. The plurality of burner bodies have their upper surfaces as flame hole surfaces for combustion of gas, and in the plurality of burner bodies, primary air mixed with gas is supplied from a fan, and the combustion gas is supplied to the plurality of burner bodies. The installation area of the device body is also supplied with secondary air upward from its lower side. This secondary air serves to improve the flame retention of each burner body.

However, there is room for improvement in the prior art as described below.

That is, when the secondary air is supplied upward from below to an area in which a plurality of burner bodies are arranged side by side, the secondary air is caused to travel upward at a moderate flow velocity between the burner bodies. Thereby, the flame retention property of the burner body can be improved. However, among the plurality of burner bodies, it is difficult to appropriately generate the flow of secondary air as described above on the outer side of the endmost burner body located at the endmost portion of the array. As a result, the flame retention of the endmost burner body may be deteriorated.

Regarding the burner body, for example, there is a rich-lean burner type, which generates a thin flame inside the flame hole surface, and generates a dense flame on both sides of the flame hole surface as an auxiliary flame, thereby improving the overall flame retention and achieving a low burner. NO _Xification . However, even in the case of using such a burner body, there may be a risk of poor flame retention of the rich flame for the endmost burner body. If the flame retention of the dense flame becomes poor, the thin flame with a lower flame retention will also be affected, resulting in poorer overall flame retention. It is desirable to properly eliminate this situation.

[Prior art literature]

[Patent Document]

[Patent Document 1] Japanese Patent Application Laid-Open No. 04-25924

[Patent Document 2] Japanese Patent No. 5554027

Contents of the invention

[Problem to be Solved by the Invention]

The present invention was conceived based on the above circumstances, and an object of the present invention is to provide a burner device capable of improving flame retention properties with a simple configuration.

[Technical means to solve the problem]

In order to solve the above-mentioned problems, the present invention proposes the following technical means.

The burner device provided by the present invention has: a burner housing, which accommodates a plurality of burner bodies whose upper surface is used as a flame hole surface; Between the side wall parts of the burner housing, the endmost burner body is located at the endmost part of the arrangement of the plurality of burner bodies, and the side plate part forms a first gap, and the side plate portion forms a second gap with the endmost burner body; Air is supplied upward from the bottom of the installation area and the first gap, and the air is blown out from a fan attached to the burner housing; and the side plate forms an opening for taking in air, and the air The intake opening allows part of the air supplied from the air flow path toward the first gap to flow into the second gap.

According to such a configuration, the following effects can be obtained.

That is, part of the air blown out from the fan and supplied toward the first gap formed between the side plate portion and the side wall portion of the burner housing through the air flow path passes through the air intake opening, thereby flowing into the In the second gap between the endmost burner body and the side plate. As a result, an upward air flow having an appropriate air volume and flow velocity can be properly generated near the outer side (side wall portion side of the burner housing) of the flame generated on the flame hole surface of the endmost burner body. Thereby, the flame holding performance of the endmost burner body can be improved more than conventionally.

In addition, since the air passing through the first gap and the second gap cools the side plate portion, it is also possible to obtain an effect of preventing heat damage to the side plate portion.

In addition, there may also be air gradually passing through the first gap while remaining as it is facing upward, and this air can be used for cooling the side wall portion of the burner housing.

In the present invention, it is preferable that the upper region of the side plate part faces the upper side of the endmost burner body substantially in parallel, and the height of the side plate part is set to be equal to the height of the endmost burner body. The height is approximately the same as or below the height of the endmost burner body.

According to such a configuration, it is more preferable that an air flow having an appropriate amount and flow velocity is formed on the upper side portion of the flame hole surface of the endmost burner body. In addition, it is also possible to more reliably prevent the side plate portion from being thermally damaged by the flame at the time of driving combustion of the burner body at the endmost portion.

In the present invention, it is preferable to provide as the air intake opening a first air intake opening provided with an air intake guide on an upper edge, and the air intake guide is formed from the upper edge. The protruding piece protrudes toward the side wall portion of the burner housing, and the protruding piece is downward or inclined downward.

According to such a configuration, the presence of the air intake guide portion provides an effect of increasing the amount of air flowing from the first gap to the second gap through the first air intake opening. As a result, the amount of air flowing through the second gap and the upper side portion of the endmost burner body is reliably prevented from being insufficient.

In this invention, it is preferable that the said air intake guide part is inclined so that it may approach the said side wall part of the said burner housing toward the lower side.

According to such a configuration, when the air passing upward through the first gap contacts the air intake guide portion, the air is smoothly guided into the second gap. Therefore, in addition to the advantage of increasing the inflow of air from the first gap to the second gap, the turbulent flow of air in the second gap can be minimized to further improve the flame retention.

In the present invention, it is preferable to include a burner unit configured to hold the plurality of burner bodies in a holder and housed in the burner housing in a manner that can be taken out from the outside, and the holder includes: a base member of the plate portion, the rectifying plate portion is provided with the plurality of burner bodies in parallel, and a plurality of ventilation holes constituting a part of the air flow path are provided; and a frame-shaped member is attached to the on the base member, and surround at least a part of the periphery of the plurality of burner bodies in such a manner as to realize the fixation of the plurality of burner bodies; a part of the frame-shaped member is the side plate portion.

According to such a configuration, by putting the burner unit into the burner case or taking it out of the burner case, a plurality of burner bodies can be assembled together in the burner case or taken out. Therefore, the assembly workability and maintenance workability of the burner device can be improved. On the other hand, since part of the frame-shaped member constituting the holder of the burner unit is used as the side plate portion, the configuration is reasonable. There is no need to use a dedicated member for the side plate portion, and it is possible to reduce the manufacturing cost.

In the present invention, it is preferable that the lower edge portion of the side plate portion is set so as to be away from the rectifying plate portion above the rectifying plate portion, and is provided with a The second air intake opening formed so that the edge portion and the rectifying plate portion are open to each other serves as the air intake opening.

According to such a configuration, the inflow amount of air from the first gap to the second gap can be increased.

Other characteristics and advantages of the present invention will be further clarified from the description of the embodiments of the present invention below with reference to the accompanying drawings.

Description of drawings

Fig. 1 is a perspective view showing an example of a burner device of the present invention.

Fig. 2 is an exploded perspective view of the burner device shown in Fig. 1 .

Fig. 3 is a III-III sectional view of Fig. 1 .

FIG. 4 is a cross-sectional view of IV-IV in FIG. 1 .

FIG. 5 is an enlarged sectional view of main parts of FIG. 4 .

Fig. 6 is an exploded perspective view of a holder and a burner body constituting the burner unit shown in Fig. 2 .

FIG. 7 is an exploded perspective view of the holder shown in FIG. 6 .

FIG. 8 is a side cross-sectional view of the holder shown in FIG. 7 .

FIG. 9 is an exploded cross-sectional view of FIG. 8 .

Fig. 10 is a sectional view of main parts showing another example of the present invention.

Explanation of symbols

1: Burner housing

2: Auxiliary board

3: Burner body

3A: The end burner body

4: Base member

6: Frame-like components

7a, 7b, 7c: Screws

10: Front opening

11: Upper surface opening

12: Upper front wall

18: side wall

19: Bottom wall

30a, 30b: gas inlet

31: flame hole surface

40: rectifier board part

40a: Air vent

41: front wall

42, 62a, 62b: Recesses for positioning

44: Air supply port

45: Foot

46: Slit for engagement

47: Recessed part for engagement

50: fan

51: Gas injection head

59: Main air flow path

60: Rear wall

61: side panel

61a: Convex part for engagement

61b: recessed part for engagement

61c: convex part

61d: lower edge

70, 71: screw through hole

72, 73: threaded hole

78: Ignition plug

79: Pillar of Fire

81: First Gap

82: Second Gap

91: First air intake opening

92: Second air intake opening

93, 93A: Air intake guide

93a: Occluded wall

AF: air flow

B: Burner device

H: Holder

h1, h2: height

U: burner unit

W1, W2: Width

Detailed ways

Hereinafter, preferred embodiments of the present invention will be specifically described with reference to the drawings.

The burner device B shown in FIG. 1 is used, for example, as a component of a gas hot water supply system, and a heat exchanger (not shown) through which hot water flows is mounted on the upper side of the burner device B. The hot water sent into the heat exchanger can be heated by driving the burner unit B for combustion.

This burner device B includes a burner housing 1 , a burner unit U housed in the burner housing 1 , and an auxiliary plate 2 attached to the front surface portion of the burner housing 1 .

As shown in detail in FIG. 2 , the combustor housing 1 has a substantially rectangular parallelepiped shape having a front opening 10 and an upper opening 11 . The sub-plate 2 is attached to the burner housing 1 and the burner unit U using a plurality of screws 7 a and 7 b so as to close the upper region of the front opening 10 . More specifically, the upper portion of the auxiliary plate 2 is attached to the upper front wall of the burner housing 1 corresponding to the upper edge portion of the front opening 10 by using the screws 7a, the screw insertion holes 70, and the threaded holes 73. Section 12. On the other hand, the lower part of the sub-plate 2 is attached to the upper part of the front wall part 41 of the burner unit U mentioned later by the screw 7b, the screw insertion hole 71, and the threaded hole 72. As shown in FIG. 3 , a glow plug 78 for driving combustion of the burner unit B, a flame rod 79 for flame detection, and the like are attached to the sub-plate 2 . With the auxiliary plate 2 removed from the burner housing 1 and the burner unit U, the burner unit U can be put into the burner housing 1 from the front through the front surface opening 10 or taken out to the burner housing 1. Outside the burner housing 1.

The burner unit U is formed by assembling a plurality of burner bodies 3 (gas combustion tubes) on a holder H in a side-by-side state. Each burner body 3 is of a type called a rich-lean burner, for example, the same as conventionally known burner bodies described in Japanese Patent Application Laid-Open No. 2013-242080 or the like. As shown in detail in FIG. 6 , each burner body 3 is generally relatively flat, has a gas inlet 30a and a gas inlet 30b at one end (front end), and has a flame hole surface 31 on the upper surface.

Details of the holder H of the burner unit U will be described later. The burner unit U is accommodated in the burner housing 1 in the state shown in FIGS. 3 and 4 . In FIG. 3 , a fan 50 and a gas injection head 51 are attached to the lower portion and the front portion of the burner housing 1 . Among the air supplied from the fan 50 to the burner housing 1, the primary air for combustion passes through the main air passage 59 in the lower part of the burner housing 1 and reaches the air supply port 44 described later. The gas injected from the nozzles of the burner is introduced into the gas inlet 30a and the gas inlet 30b of the burner body 3 together. The gas burns on the flame hole surface 31 and above. Among the air supplied from the fan 50 to the main air flow path 59 , the air other than the primary air passes upward through a plurality of ventilation holes 40 a of the rectifying plate portion 40 of the holder H which will be described later. Accordingly, secondary air for combustion is supplied to the installation area of the plurality of burner bodies 3 (including the second gap 82 described later). Air is also supplied to the first gap 81 described later.

The main air flow path 59 and the plurality of vent holes 40a constitute an "air flow path" in the present invention.

As shown in FIG. 7, the holder H of the burner unit U is comprised combining the base member 4 and the frame-shaped member 6. As shown in FIG. Both the base member 4 and the frame-shaped member 6 are formed by pressing a metal plate or the like.

The base member 4 includes a straightening plate portion 40 functioning as a bottom wall portion on which a plurality of combustor bodies 3 are placed, a plurality of leg portions 45 protruding downward from the straightening plate portion 40 , and a front portion of the straightening plate portion 40 . The front wall part 41 which stands upright. In the front wall portion 41, a plurality of gas supply ports 44 facing the gas inlet 30a and the gas inlet 30b, and multiple holes for inserting the front ends of the plurality of burner bodies 3 and realizing their positioning and fixing are formed. a positioning recess 42. The plurality of leg portions 45 are portions placed on the bottom wall portion 19 of the combustor housing 1 , whereby the main air flow path 59 is formed between the bottom wall portion 19 and the straightening plate portion 40 .

The frame-shaped member 6 of the holder H is formed by connecting a rear wall portion 60 and a pair of left and right side plate portions 61 for surrounding the rear side and left and right sides of a plurality of burner bodies 3, and is approximately “匸” in plan view. word shape. On the upper end and the lower end of the rear wall portion 60, a plurality of positioning recesses 62a and 62b are provided for fitting the rear end portions of the plurality of burner bodies 3 to position and fix them.

As shown in FIGS. 8 and 9 , the pair of side plate portions 61 are attached to the base member 4 with screws 7c. As a mechanism for assisting this installation to securely fix the side plate portion 61, an engaging convex portion 61a is provided at the rear lower portion of the side plate portion 61, and the engaging convex portion 61a is inserted into a hole provided in the base member 4. In the slit 46 for engagement, the front edge portion of the slit 46 for engagement can be engaged. An engaging recess 61b is provided on the upper front side of the side plate portion 61, and the engaging recess 61b can be engaged in the engaged recess 47 provided in the base member 4 (see also the enlarged perspective view of the main part of FIG. 7).

As shown in FIGS. 4 and 5 , a pair of side plate portions 61 are located at the left and right pair of endmost burner bodies 3 (3A) at the endmost portions of the arrangement of the burner bodies 3 among the plurality of burner bodies 3 , and are connected to the burner bodies 3 (3A). A pair of left and right side wall parts 18 of the device case 1 are mutually spaced. A first gap 81 is formed between the side plate portion 61 and the side wall portion 18 , and a second gap 82 is formed between the side plate portion 61 and the endmost burner body 3A.

As shown in detail in FIG. 5 , the side plate portion 61 is further provided with a first air intake opening portion 91 and a plurality of convex portions 61c. In addition, the side plate portion 61 forms a second air intake opening portion 92 .

The plurality of protrusions 61c are located on the upper portion of the side plate portion 61 and are in the shape of a small hemisphere or the like protruding in the horizontal direction. The second gap 82 is formed between the endmost burner body 3A and the side plate portion 61 by setting these plurality of protrusions 61c in contact with the outer surface of the endmost burner body 3A. . The width W1 of the second gap 82 is, for example, approximately the same as the width W2 of the gaps in the upper parts of the other plurality of burner bodies 3 . But not limited to this.

The first air intake opening 91 is a through-hole formed in an upper region of the side plate 61 and has a substantially rectangular shape extending in the front-rear direction (see also FIG. 8 , FIG. 9 , etc.). However, an air intake guide portion 93 is continuously provided on the upper edge portion of the first air intake opening portion 91 . The air intake guide portion 93 is in the shape of an obliquely downward protruding piece protruding from the upper edge portion toward the side wall portion 18 , and as shown in FIG. way slanted. The air intake guide portion 93 is formed by subjecting the side plate portion 61 to drawing, cutting, or the like. According to the drawing process, the closed wall portions 93a (refer to FIG. 8, FIG. 9, etc.) can be formed at both ends of the air intake guide portion 93 in the longitudinal direction (the front and rear directions of the side plate portion 61), so that the air intake guide The inner regions of both ends in the longitudinal direction of the portion 93 are not opened in the front-rear direction. This is advantageous in increasing the amount of air flowing from the first gap 81 into the second gap 82 through the first air intake opening 91 .

The second air intake opening 92 is formed by notching the lower edge portion 61d of the side plate portion 61 and disposing the lower edge portion 61d away from the rectifying plate portion 40 upward. That is, the opening between the lower edge portion 61 d and the rectifying plate portion 40 serves as the second air intake opening 92 .

The upper region of the side plate portion 61 faces the upper side surface of the endmost burner body 3A substantially in parallel. In addition, it is preferable that the height h1 of the side plate part 61 is substantially the same as the height h2 of 3 A of most end part burner main bodies, or it is made into a height slightly lower than height h2. But not limited to this.

Next, the operation of the burner device B will be described.

First, when each burner body 3 is driven by combustion while the fan 50 is driven, part of the combustion air supplied from the fan 50 to the main air passage 59 passes through the plurality of vent holes 40a and is supplied as secondary air. In the installation area of multiple burner bodies 3 (including the second gap 82). At this time, air is also supplied to the first gap 81 . A part of the air supplied to the first gap 81 continues to rise along the side wall portion 18 of the combustor housing 1 , but it functions to cool the side wall portion 18 and prevent thermal damage. As a method for more reliably preventing thermal damage to the side wall portion 18 , a configuration may also be provided in which a heat insulating plate facing each other through an air layer is provided to the side wall portion 18 .

On the other hand, another part of the air supplied to the first gap 81 flows into the second gap 82 through the first air intake opening 91 . In this case, the air intake guide portion 93 plays a role of promoting the inflow of air from the first gap 81 to the second gap 82 . As a result, the amount of air flowing upward in the second gap 82 can be increased, and an upward airflow AF with an appropriate volume and velocity can be continuously generated near the outer side of the flame generated on the flame hole surface 31 of the endmost burner body 3A. (illustrated schematically using arrows). As a result, the amount of secondary air supplied to the flame forming region of the endmost burner body 3A is not insufficient, and the flame holding performance can be improved.

The second air intake opening 92 functions to let a part of the air that passes through the vent hole 40 a toward the first gap 81 flow into the second gap 82 . Thereby, the inflow amount of air into the second gap 82 can be increased, and the flame holding performance can be improved more reliably.

As described above, the upper region of the side plate portion 61 faces the upper side surface of the endmost burner body 3A substantially in parallel at an appropriate interval (width W1). In addition, the height h1 of the side plate portion 61 is set to be substantially the same as or slightly lower than the height h2 of the endmost burner body 3A. Therefore, the air flow AF becomes more preferable in terms of improving the flame holding property of the endmost burner body 3A. Unlike the present embodiment, when the height h1>height h2, the side plate portion 61 may be heated to a high temperature to cause a risk of thermal damage. On the other hand, according to the present embodiment, such a risk can be appropriately eliminated.

In this embodiment, a burner unit U is provided in which a plurality of burner bodies 3 are held in a holder H, and this burner unit U can be removed from the burner housing 1 with the auxiliary plate 2 Next, put it into the burner housing 1 or take it out of the burner housing 1 through the front surface opening 10 . Therefore, maintenance work and the like of the burner body 3 are also easy. On the other hand, the mechanism for improving the flame retention of the endmost burner body 3A is constituted by using the side plate portion 61 of the holder H constituting the burner unit U. As shown in FIG. Therefore, the structure is reasonable, and a special member for improving the flame retaining property is not separately used, so that the manufacturing cost can also be reduced.

Fig. 10 shows another embodiment of the present invention.

In this figure, the shape of 93 A of air intake guide parts differs from the said embodiment, and the lower end part of 93 A of air intake guide parts does not incline but extends downward. However, the air intake guide portion 93A protrudes closer to the side wall portion 18 than other general portions of the side plate portion 61 in the horizontal direction. Therefore, the air intake guide portion 93A of the present embodiment also exerts the effect of efficiently guiding the air traveling upward in the first gap 81 to the first air intake opening portion 91 and making the air flow to the second gap 82 Air inflow increases.

As understood from this embodiment, the specific shape of the air intake opening can be changed in various ways.

The present invention is not limited to the contents of the above-described embodiments. The specific configuration of each part of the burner device of the present invention can freely undergo various design changes within the intended scope of the present invention.

In the above-described embodiments, a burner unit is formed by holding a plurality of burner bodies in a holder, and this burner unit can be put into the burner case or taken out of the burner case, but the present invention It is also possible to set it as a structure different from this. For example, Patent Document 2 discloses a configuration in which a plurality of burner bodies are individually incorporated into a burner housing, and such a configuration can also be employed. In this case, what is necessary is just to make the board|plate located outside the outermost burner main body the side plate part mentioned in this invention, and to form the opening part for air intake.

The specific shape, size, and number of openings for taking in air are not limited as long as they allow a part of the air supplied from the air flow path toward the first gap to flow into the second gap. It is good also as the structure which does not provide the air intake guide part in the upper edge part of the opening part for air intake.

The burner body does not necessarily have to be a rich-lean burner, and a different type (for example, an all-primary-air burner, etc.) may be used.

The burner device of the present invention is not limited to a hot water supply device, for example, it can be used for a warm air device or an incineration device, and its specific application is not limited.

Claims (10)

1. a kind of burner apparatus, which is characterized in that including：

Burner shell accommodates multiple burner bodies that upper surface part is set as to flame hole face side by side；

Side plate configures between most front burner ontology and the side of sidewall portion of the burner shell, the most cigarette burning Device ontology is located at the arrangement most end of the multiple burner body, and the side plate forms between the side of sidewall portion One gap, and the side plate forms the second gap between the most front burner ontology；And

Air flow circuit, can be towards the setting area of the multiple burner body and first gap and from the setting area And the lower section in first gap supplies air upwards, the air is sprayed from the fan on the burner shell； And

The side plate forms air and is taken into opening portion, and the air, which is taken into, can be made with opening portion from the air flow circuit direction A part for the air of the first gap supply is flowed into second gap.

2. burner apparatus according to claim 1, it is characterised in that：

Upper side of the upper area of the side plate substantially in parallel towards the most front burner ontology, and the side The height of plate portion is set to roughly the same with the height of the most front burner ontology or described most front burner ontology Below height.

3. burner apparatus according to claim 1 or 2, it is characterised in that：

Have to be equipped with air in upper edge and be taken into the first air of guide portion and is taken into opening portion is used to be taken into use as the air Opening portion,

The air be taken into guide portion be close to from the upper edge burner shell the side of sidewall portion it is outstanding prominent Sheet, the tab shape is downwards or diagonally downward.

4. burner apparatus according to claim 3, it is characterised in that：

The air be taken into guide portion by more to lower side then closer to the side of sidewall portion of the burner shell in a manner of incline Tiltedly.

5. burner apparatus according to claim 1 or 2, it is characterised in that：Have burner unit, the burner list Member is that the multiple burner body is maintained in holder and is constituted, and is housed in institute in a manner of it can be taken out to outside It states in burner casing body,

The holder has：Base component with rectification plate portion, the rectification plate portion carries side by side is equipped with the multiple combustion Burner ontology, and equipped with the multiple ventilation holes for the part for constituting the air flow circuit；And frame member, it is mounted on described On base component, and by realize the multiple burner body it is fixed in a manner of surround around the multiple burner body At least part；

A part for the frame member is the side plate.

6. burner apparatus according to claim 3, it is characterised in that：Have burner unit, the burner unit It is that the multiple burner body is maintained in holder and is constituted, and is housed in described in a manner of it can be taken out to outside In burner casing body,

The holder has：Base component with rectification plate portion, the rectification plate portion carries side by side is equipped with the multiple combustion Burner ontology, and equipped with the multiple ventilation holes for the part for constituting the air flow circuit；And frame member, it is mounted on described On base component, and by realize the multiple burner body it is fixed in a manner of surround around the multiple burner body At least part；

A part for the frame member is the side plate.

7. burner apparatus according to claim 4, it is characterised in that：Have burner unit, the burner unit It is that the multiple burner body is maintained in holder and is constituted, and is housed in described in a manner of it can be taken out to outside In burner casing body,

The holder has：Base component with rectification plate portion, the rectification plate portion carries side by side is equipped with the multiple combustion Burner ontology, and equipped with the multiple ventilation holes for the part for constituting the air flow circuit；And frame member, it is mounted on described On base component, and by realize the multiple burner body it is fixed in a manner of surround around the multiple burner body At least part；

A part for the frame member is the side plate.

8. burner apparatus according to claim 5, it is characterised in that：

The lower edge portion of the side plate is in a manner of being configured to the top of the rectification plate portion far from the rectification plate portion Setting, and

Have by formed in such a way that the lower edge portion of the side plate and the rectification plate portion are open between each other the Two air, which are taken into, to be used opening portion to be taken into as the air to use opening portion.

9. burner apparatus according to claim 6, it is characterised in that：

The lower edge portion of the side plate is in a manner of being configured to the top of the rectification plate portion far from the rectification plate portion Setting, and

Have by formed in such a way that the lower edge portion of the side plate and the rectification plate portion are open between each other the Two air, which are taken into, to be used opening portion to be taken into as the air to use opening portion.

10. burner apparatus according to claim 7, it is characterised in that：

The lower edge portion of the side plate is in a manner of being configured to the top of the rectification plate portion far from the rectification plate portion Setting, and

Have by formed in such a way that the lower edge portion of the side plate and the rectification plate portion are open between each other the Two air, which are taken into, to be used opening portion to be taken into as the air to use opening portion.