JPH1144129A - Externally facing centralized smoke stack - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an enclosed centralized smoke stack whose external appearance can be made beautiful by reducing generation of the downwash of flue gas. SOLUTION: An enclosed centralized smoke stack 1 is composed of a flue gas tube 3 composed of plural tubular bodies 3', a smoke gathering part 5 to gather upper end parts of the tubular bodies 3' and a flue gas port on the upper end of the smoke gathering part 5, a support structure body 2 in which a clearance 8 is arranged outside the flue gas tube 3 and support beams 4 are arranged in an intermediate part and which supports the flue gas tube 3, a top part stage 7 laid on an upper end inner periphery of the support body structure 2 so as to surround the smoke gathering part 5, air inlets 9 arranged in an intermediate part of the support body structure 2 in the vicinity of the support beams 4 and air outlets 10 which are arranged in the top part stage 7 and form an air curtain by exhausting the rising atmosphere 15 rising in the clearance 8 to a periphery of flue gas 12 exhausted from a flue gas port 6. Therefore, the downwash can be reliably prevented, and the upper end of the smoke stack does not become a heavy body with simple constitution, and a design load can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exterior collective chimney for discharging exhaust gas generated in a power generation device for thermal power generation or the like into the atmosphere.

[0002]

2. Description of the Related Art When exhaust gas generated in thermal power generation or the like is discharged into the atmosphere from the upper end of a chimney having a cylindrical shape such as a cylindrical shape, a wind blown from the side into the chimney causes a flue gas to be generated on the leeward side of the chimney. Karman vortices are generated alternately left and right. This Karman vortex generates a negative pressure area on the leeward side of the chimney, and a part of the smoke exhausted from the upper end of the chimney is sucked into the negative pressure area, and the flow of the descending smoke exhaust, a so-called downwash. And the spread of smoke on the ground may cause pollution problems. Prevent the occurrence of this downwash,
Various devices have been proposed in the past to avoid the occurrence of pollution problems and the like due to smoke exhaust diffusion.

FIG. 5 shows an apparatus for preventing the occurrence of such a downwash.
It is a figure which shows the upper end part of the chimney proposed in No. 38 "downwash prevention apparatus of the chimney made from a reinforced concrete." In the drawings, the left side shows a cross-sectional view and the right side shows a side view.

[0004] In the figure, reference numeral 21 denotes a con- nected outer cylinder 21a standing on the ground and a gap 2 inside the outer cylinder 21a.
2, a chimney having the same height as the outer cylinder 21a and having a double cylinder structure with the inner cylinder 21b erected on the ground.
At the upper end of the outer cylinder 21a, a ventilation hole 23 penetrating obliquely upward from the gap 22 is provided, and at the lower end, a ventilation hole having a structure similar to the ventilation hole 23 (not shown) is provided. Is provided. The air introduced from the air collection holes into the gap 22 becomes ascending air (hereinafter referred to as rising air), rises in the gap 22, is discharged from the ventilation holes 23, and flows naturally through the gap 22, thereby increasing the inside. The heat of the inner cylinder 21b, which is heated by the flue gas passing through the inner cylinder 21b, is removed to allow natural cooling.

A guide nozzle 24 formed in a hat shape is provided on the outer periphery of the upper end of the chimney 21. The guide nozzle 24 is provided with a chimney 21 for taking in an atmosphere 25 having a lateral component blown in opposition.
An opening 24a opened in all directions on the outer periphery of the upper end portion of
While gradually reducing the cross-sectional area from this opening 24a,
Wind path 24d deflecting air 25 upward from horizontal direction
Consists of

In the air passage 24d, an opening 24a formed on the entire periphery of the upper end of the chimney 21 is inserted into the air passage 24d.
d, a vertical plate 24c forming a guide nozzle 24 formed in a passage parallel to the periphery of the upper end of the chimney is provided, and the upper end of the wind passage 24d. The atmosphere 2 flowing through the wind passage 24d
5 is provided with an exhaust port 24b for making a vertical upflow 25a. Further, around the guide nozzle 24 above the opening 24a, there is provided a landing area 26 with handrails laid horizontally so as to make a round around the outer periphery of the upper end portion of the chimney 21 and also to avoid rain.

In the chimney 21 configured as described above,
When the air 25 having a lateral component is blown into the opening 24a, the air 25 is accelerated in the air passage 24d, is deflected upward and blows out vertically from the exhaust port 24b, and the outer periphery of the outer cylinder 21a on the windward side. Generates a blow-up flow 25a,
An air curtain is formed above the exhaust port 24b on the windward side.

[0008] Due to the air curtain effect of the blow-up flow 25a, the smoke exhausted from the smoke outlet 21c at the upper end of the inner cylinder 21b located on the downstream side where the air curtain is formed, is blown sideways to the chimney 21. Atmosphere 2 with directional component
5, the occurrence of downwash is reduced, and the occurrence of pollution problems can be reduced. In addition, the atmosphere 25, which has an increased speed in the wind passage 24d and flows upward, has a ventilation hole 2 provided at the upper end of the outer cylinder 21a.
The rising air naturally flowing through the gap 22 and flowing out of the gap 3 joins.

However, in the chimney 21 configured as described above, the updraft 25a generated by the guide nozzle 24 is generated only on the windward side of the chimney 21 according to the wind direction, and is almost generated on the leeward side. Therefore, the air curtain due to the updraft 25a hardly occurs on the leeward side.

For this reason, on the windward side of the chimney 21, the smoke discharged from the smoke outlet 21c and flowing to the leeward side has an effect of reducing downwash by an air curtain formed on the windward side. On the lee side of the outer cylinder 21a, which is at the same height as the smoke outlet 21c, a part of the smoke
It cannot be prevented from being drawn into the negative pressure region generated on the leeward side of a, and the generation of downwash cannot be effectively prevented.

Further, the air naturally circulates in the gap 22 and the air passage 2
The rising air joining the rising air 25 in the inside 4 is affected not only by the wind direction but also by the gap 22 similarly to the blowing flow 25a.
Is smaller, the flow velocity is smaller and the contribution to the formation of the air curtain is smaller than that of the atmosphere 25 which rises in the wind passage 24d and rises. The rising atmosphere makes it difficult to reduce downwash.

Further, at low wind speeds, the updraft 25a is weakened, and the contribution of the rising air joining the atmosphere 25 to the updraft 25a is also reduced. There is a problem that cannot be prevented. Further, the weight of the hat-shaped guide nozzle 24 provided at the upper end of the outer cylinder 21a increases, the design load of the outer cylinder 21a for supporting the same increases, the construction cost of the chimney increases, and the upper end of the chimney 21 increases. There is a problem that the portion is exposed and the appearance of the chimney 21 is deteriorated.

In particular, in recent years, a high-rise chimney installed near a city has been considered to have a structure of the chimney 21 in consideration of only the above-described function of avoiding the pollution problem, with an emphasis on the conventional downwash and the like. In addition to these functions, an exterior-type chimney that takes into consideration an aesthetic appearance has been attracting attention.

FIG. 6 is a side view showing a top part of such an exterior-type collective chimney in a partially broken section, and FIG. 7 is a perspective view showing the top part in a partially broken section. In the figure, reference numeral 31 denotes a semi-monocoque structure which is erected on the ground and integrated with an exterior plate, and has a cylindrical support structure 32 having a substantially square cross section.
It is made up of four smoke exhaust tubes 33 which are erected in the support structure 32, are heat-extensible, and whose intermediate part is supported by the support structure 32 by the support beam 34 and which is higher than the support structure 32 by 2 to 3 m. This is an exterior type chimney.

[0015] 35 is provided at the upper end of the smoke stack 33,
A smoke collection unit 36 for collecting the four smoke collection tubes 33 is a smoke collection opening formed at the upper end of the smoke collection unit 35, and the smoke collection tube 33 is a smoke collection unit 35 and a smoke collection opening 36 in a broad sense. Consists of 37
Is a top stage that surrounds the outer periphery of the smoke collecting section 35 and is stretched on the inner periphery of the upper end of the support structure 32.

Reference numeral 38 denotes a ventilation air inlet gallery formed at a plurality of positions in the circumferential direction of the support structure 32 above the height position where the support beams 34 are provided, and 39 denotes a top stage 3.
The ventilation air outlet gutters 40 pierced at a plurality of locations in the circumferential direction of the support structure 32 immediately below the support structure 32 are provided on the support structure 32.
Formed between the inner circumference of the cylinder and the outer surface of the smoke stack 33, 4
Reference numeral 1 denotes a lattice-shaped blindfold structure that is provided upright at the upper end of the support structure 32 in the circumferential direction.

Conventionally-collected exterior chimney 3
1 has such a configuration, so that it is heated by high-temperature exhaust gas passing through the inside, and is heated through the support structure 32 heated by the sunshine. The heat is removed by the rising air that flows into the gap 40 from the air inlet gallery 38 and flows out of the air outlet gallery 39, and is naturally cooled.

Further, since the height of the four smoke stacks 33 is higher than the support structure 32 by 2 to 3 m, the smoke stacks 36
In addition to reducing the occurrence of downwash of smoke exhausted from the hood, the blind structure 41 is erected in the circumferential direction at the upper end of the support structure 32, so that the aesthetic appearance is not impaired and the blind structure 41 is The occurrence of downwash is further reduced in combination with the fence-like shape which does not obstruct the flow of the atmosphere 25 having the directional component.

However, since such an exterior-type chimney stack 31 has the grid-shaped blindfold structure 41 erected over the entire circumferential direction of the upper end of the support structure 32, the design, manufacture, and mounting of the blindfold structure 41 are performed. Work is required in addition to the conventional chimney construction work, and there is a problem that extra cost and construction period are required for the construction of the exterior type chimney 31.

[0020]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the above-mentioned conventional chimney used for discharging smoke emitted from a power generation device in a thermal power plant or the like to the atmosphere. In order to reduce the generation of downwash that occurs downstream of the chimney, prevent the occurrence of pollution problems, and achieve an aesthetic appearance at the top of the chimney, without requiring extra cost and construction time for construction It is an object of the present invention to provide an exterior type chimney that can be realized with a simple configuration.

[0021]

For this reason, the armored stack chimney of the present invention has the following means.

(1) A plurality of cylinders erected adjacent to the ground, provided at the upper end of the cylinder, a smoke collecting section for gathering the upper ends of the plurality of cylinders, and provided at an upper end of the smoke collecting section. In addition, a flue gas cylinder including a flue gas outlet that collects the ascending flue gas dispersed inside each of the plurality of cylindrical bodies and discharges the flue gas to the atmosphere is provided. It is preferable that the number of the cylinders is 3 to 4 in accordance with the amount of smoke exhausted to the atmosphere and in consideration of the weight at the time of construction. Further, it is preferable to provide a heat-resistant lining or the like inside the cylindrical body in order to increase the durability against the high temperature and the corrosiveness of the flue gas.

(2) Smoke exhaust gas which surrounds the outside of the smoke exhaust tube, stands upright on the ground with a gap from the outer periphery of the smoke exhaust tube, and is provided with a support beam on the inner periphery at an intermediate height. Thus, a supporting structure is provided which is capable of supporting the smoke stack which expands and contracts when it is heated and stretched, so that the smoke stack can move up and down freely. Note that the support beams are preferably provided at a plurality of positions in the height direction of the support structure.
The support structure preferably has a semi-monocoque structure integrated with a weather-resistant exterior plate, and more preferably has a substantially square horizontal cross section.

(3) A top stage is provided, which surrounds the outer periphery of the smoke collection section provided at the upper end of the smoke exhaust tube and is laid horizontally between the outer periphery of the smoke collection section and the inner periphery of the upper end of the support structure. Was. In addition, it is preferable that the top stage can also be used to avoid rain in a gap formed between the outer cylinder of the smoke exhaust cylinder and the inner peripheral surface of the support structure.

(4) Height near the support beam, preferably
At a position directly above each of the support beams provided at a plurality of positions in the height direction of the support structure, the support beams are provided so as to penetrate the side of the support structure, and air is taken in between the smoke stack and the support structure from the outside. An air inlet was provided. Preferably, a plurality of air inlets are provided around the side of the support structure, and more preferably, the air inlets are provided at the center of each of the four flat sides of the support structure.

(5) The rising air, which is provided on the top stage, is taken in from the air inlet, and rises between the inner periphery of the support structure and the outer periphery of the smoke stack including the smoke collecting portion, is discharged above the top stage. An air outlet for discharging air was provided on the outer peripheral side of the smoke tube.
The air outlet is provided around the smoke collecting section on the floor of the top stage, and the ring-shaped section is made into a U-shaped section, which is alternately turned upside down, and It is preferable to form an air outlet louver so as to block drainage and drain and to allow the rising air to flow freely.

A. According to the exterior-type collective chimney of the present invention, by the means (1) to (5) described above, the smoke exhaust that is dispersed and ascends inside each of the plurality of cylinders provided in the smoke exhaust cylinder is reduced by the cylindrical body. The smoke gathers at the smoke collecting section at the upper end and is discharged into the atmosphere from the smoke outlet. On the other hand, from the air inlet provided through the side of the support structure at the height near the support beam, in any wind direction, the air gap between the smoke stack and the support structure is increased. It is taken in and rises, and is powerful by a large amount of rising air discharged above the top stage from the air outlet installed on the top stage, which is provided between the outer circumference of the smoke collection section and the inner circumference of the upper end of the support structure. A simple air curtain is formed.

Due to the air curtain effect, the smoke discharged from the smoke outlet into the atmosphere is less affected by the atmosphere having a lateral component, and is sucked into a negative pressure region where the smoke is generated on the leeward side. Downwash that occurs on the leeward side is reduced, especially when the upstream speed is low, and when the atmospheric speed with the lateral component is low, the occurrence of pollution problems is reduced. it can.

The top stage provided at the upper end of the smoke stack, surrounding the outer periphery of the smoke collector, and horizontally laid between the outer periphery of the smoke collector and the inner periphery of the upper end of the support structure, As compared with the hat-shaped guide nozzle shown in FIG. 5, the weight can be reduced, the design load does not increase, and the design and manufacturing costs are higher than when the blindfold structure shown in FIGS. 6 and 7 is provided. Can be reduced, and work at heights for mounting can be reduced, and the construction period can be shortened. Furthermore, the installation of the top stage, coupled with the reduction of the occurrence of downwash, can improve the aesthetic appearance and prevent the rain from being blown into the gap.

Further, the second exterior type chimney according to the present invention employs the following means. (6) The height of the plurality of smoke stacks erected on the ground is made equal to or slightly higher than the height of the support structure that is erected with a gap provided on the outer peripheral side of the smoke stack.

The exterior type chimney according to the present invention has the above-mentioned (6).
By means, in addition to a above, b. The smoke that rises while dispersing inside each of the multiple cylinders provided in the smoke stack is collected at the smoke collection section and discharged into the atmosphere from the smoke outlet. The height is set to be the same as or slightly higher than the height, so that in any wind direction, a strong air curtain effect formed by a large amount of upflow discharged from the air outlet provided on the top stage , The smoke emitted into the atmosphere from the smoke outlet rises surrounded by the air curtain,
The influence of the atmosphere having the lateral component is lessened, and the discharged smoke can further reduce downwash generated in a negative pressure region generated on the leeward side, thereby reducing the occurrence of pollution problems.

Further, since the height of the smoke stack and the supporting structure are substantially the same, the smoke outlet of the smoke stack is more difficult to see from below due to being blocked by the top stage, and the downwash described above is further reduced. Together with this, the aesthetic appearance can be further improved.

[0033]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a stack type chimney according to an embodiment of the present invention. FIG. 1 is a side view of an overall appearance showing a first embodiment of an exterior type chimney according to the present invention, FIG. 2 is a plan view taken along a line AA shown in FIG.
FIG. 3 is a horizontal sectional view taken along the line BB shown in FIG.
FIG. 3 is a horizontal sectional view taken along the line CC shown in FIG. 2.

In FIG. 1 to FIG. 4, reference numeral 1 denotes a high-rise exterior collective chimney according to the present embodiment. The exterior-type chimney stack 1 has a semi-monocoque structure in which an exterior plate is integrated, and has a tubular support structure 2 erected on the ground 13 and having a substantially square horizontal cross section, and a support structure 2. It is supported by a support beam 4 provided at an intermediate portion at a plurality of heights inside the inside thereof so as to be capable of being thermally expanded and contracted, and is made up of four cylindrical cylinders 3 ′ standing upright on the ground 13 and provided adjacent thereto. And a smoke stack 3. The smoke stack 3 composed of four cylinders 3 ′ is provided at substantially the same height as the support structure 2, or at a slightly higher height.

Reference numeral 5 denotes a smoke collecting section provided at the top of the cylindrical body 3 'for collecting the smoke exhaust which rises inside the four cylindrical bodies 3', and 6 is provided at an upper end of the smoke collecting section 5. The smoke collecting section 5 and the smoke outlet 6 are provided together with the cylindrical body 3 '.
Is configured. Reference numeral 7 denotes the outer surface of the smoke collecting section 5 and the supporting structure 2.
A top stage 8 laid horizontally between the inner surface of the support structure 2 and the upper stage 8 also serves as a rain avoider. The support stage 8 in the support structure 2 surrounded by the outer peripheral surface of the four smoke exhaust tubes 3 and the inner peripheral wall stage 7 of the support structure 2. It is a gap.

Reference numeral 9 denotes an air inlet gallery serving as a ventilation air inlet provided in four directions at the center of the smoothed side surface of the support structure 2 immediately above the height position of each support beam 4.
Reference numeral 0 denotes an air outlet louver as an air outlet provided on the floor surface of the top stage 7 and in a ring shape around the smoke collecting section 5.
Reference numeral 1 denotes an upflow of the rising air discharged through the air outlet louver 10, and reference numeral 12 denotes a flue gas discharged from the smoke outlet 6.

In FIG. 4, an air outlet louver 10 is formed by alternately combining upside-down shaped members having a U-shaped cross section, collecting rainwater into a drain pipe (not shown) and draining the rainwater. A well-known ceiling-mounted louver having a structure in which the upward and downward flow of the rising air rising in the gap 8 is free is used. The air outlet louver 10 may be provided in a continuous ring shape around the smoke collecting portion 5 as described above, or may be divided into a plurality of portions and provided at intervals around the smoke outlet 6. .

According to the above-described structure, the exterior-type chimney stack 1 of the present embodiment is arranged between the inside of the support structure 2 and the plurality of upright cylinders 3 ′ and the smoke collection section 5 constituting the smoke exhaust tube 3. The formed gap 8 has a significantly larger cross-sectional space than the gap 22 formed between the outer cylinder 21a and the inner cylinder 21b of the independent conventional double-cylinder chimney shown in FIG. It can be.

The gap 8 formed in the support structure 2
Meanwhile, the air flowing from the air inlet gallery 9 is heated by the high-temperature smoke exhaust passing through the inside thereof, is brought into contact with the outer peripheral surface of the smoke exhaust tube 3 having a high temperature, and is heated to 50 ° C. to 60 ° C. Rise to the rising atmosphere 15.

Further, since the air inlet gallery 9 is provided at a plurality of positions directly above the support beams 4 of each height, the external air 15 is also drawn in from each of the air inlet gallery 9 sequentially. Gap 8 due to convection due to the temperature difference from 15
As a result, the air flows upward and flows upward from an air outlet louver 10 provided on the floor of the top stage 7 to be released into the atmosphere as an upward flow 11. Form a curtain.

During the flue gas operation of the exterior collective chimney 1, the blow-up flow 12 is separated from the atmosphere 14 and the gap 8 by natural ventilation.
When a temperature difference of about 30 ° C. to 40 ° C. is generated between the air and the inside air, a rising air 15 having a substantially constant speed is generated due to the temperature difference regardless of the presence or absence of an external wind, and a continuous rising air is generated. Can be constantly obtained.

At this time, a fan for blowing upward air 15 upward is installed on the support beam 4 in the gap 8.
If the rising atmosphere 15 is accelerated, not only the stronger rising atmosphere flow 15 can be obtained, but also the flow of the rising atmosphere 15 becomes faster as the air outlet louver 9 is closer,
It becomes strong and is discharged into the atmosphere as a strong updraft 11 from the air outlet louver 10 to form a strong air curtain.

For this reason, the flue gas 12 discharged into the atmosphere from the smoke outlet 6 of the smoke stack 3 which is the same as or slightly higher than the support structure 2 is entirely in the height range close to the smoke outlet 6. The flue gas discharged upward from the air outlet louver 10 is surrounded by a fast and strong updraft 11, that is, a so-called air curtain, and is discharged from the flue gas outlet 6 on the windward side. As a matter of course, downwash of the smoke exhaust port discharged from the smoke exhaust port 6 located on the leeward side is surely prevented. This effect is further enhanced by installing an upward fan in the gap 8.

On the other hand, the smoke stack 3 is configured such that the upper end height is the same as or slightly higher than that of the support structure 2, so that the exterior-type stack chimney 1 is of course viewed from below. Even when viewed from the suburbs, the smoke outlet 6 at the top of the smoke stack 3 is blocked by the top stage 7 and becomes invisible. Even if the installation is omitted, the aesthetic appearance of the smoke exhaust tube 3 is not impaired, and the smoke exhaust tube 3 can have an aesthetic appearance.

Therefore, according to the above-described structure, the conventional grid-like blindfold structure 41 or the like is not used, and
Without providing the guide nozzle 24 which increases the weight,
With a simple structure as a whole, the design, manufacturing and installation costs do not increase, the construction period is not lengthened, and the design load is not increased, and the downwashing of the smoke exhaust 12 is effective. And at the same time, an effect of maintaining the aesthetic appearance of the exterior type chimney 1 is obtained.

[0046]

As described above, the exterior-type chimney stack of the present invention comprises a plurality of cylinders erected adjacent to the ground and a smoke collection section for collecting the upper ends of the plurality of cylinders. The smoke exhaust that disperses through the inside of the cylinder and collects the rising smoke is collected and discharged to the atmosphere from the smoke outlet at the upper end of the smoke collector. A support beam is provided on the inner circumference at the height of the intermediate part, and the smoke exhauster can be moved up and down to support the support structure, and the outer periphery of the smoke collector provided at the upper end of the smoke exhauster. A top stage that is surrounded and laid between the outer periphery of the smoke collector and the upper end of the support structure, and is provided so as to penetrate the side of the support structure near the support beam, and allows the atmosphere to be exhausted from outside. An air inlet to take in between the and the support structure;
Installed on the top stage, taken in from the air inlet,
An air outlet for discharging the air rising between the support structure and the upper stage is provided.

As a result, the smoke that rises while being dispersed inside each of the cylinders of the smoke stack collects in the smoke collection section and is discharged into the atmosphere from the smoke outlet. From the air inlet provided through the side of the height support structure, it is taken up between the smoke stack and the support structure and rises, and from the air outlet provided on the top stage, above the top stage Due to the generation of a strong air curtain formed by the large amount of rising air that is discharged to the smoke, the smoke discharged from the smoke exhaust port is less affected by the atmosphere, and the discharged smoke is Thus, it is less likely to be sucked into the negative pressure region, and downwash generated on the leeward side is reduced, thereby reducing the occurrence of pollution problems.

The top stage provided at the upper end of the smoke stack can be made lighter than a hat-shaped guide nozzle.
The design load does not increase, and the design and manufacturing costs can be reduced compared to the case where a blindfold structure is provided, and the work at heights for installation is reduced, and the construction period can be shortened. Is obtained. Further, the aesthetic appearance can be improved in combination with the reduction in the generation of downwash.

Further, in the exterior-type chimney stack of the present invention, the height of a plurality of smoke stacks erected on the ground is the same as the height of a support structure that is erected with a gap provided on the outer peripheral side of the smoke stack. Or slightly higher.

Thus, the smoke rising up the smoke stack is
Collected in the smoke collecting section and discharged to the atmosphere from the smoke outlet, but the smoke stack is flush with or slightly higher than the height of the support structure, so it is discharged from the air outlet provided in the top stage. In addition, the strong air curtain effect formed by the large rising atmosphere reduces the influence from the atmosphere, reduces downwash, and reduces the possibility of pollution. Further, since the height of the smoke stack and the height of the support structure are substantially the same, the smoke stack is difficult to see from below, and the aesthetic appearance can be further improved in combination with the reduction in downwashing.

[Brief description of the drawings]

FIG. 1 is an overall side view showing a first embodiment of an exterior collective chimney according to the present invention;

FIG. 2 is a plan view taken along a line AA in FIG. 1;

FIG. 3 is a horizontal cross-sectional view taken along the line BB shown in FIG.

4 is a longitudinal sectional view taken along a line CC shown in FIG. 2;

FIG. 5 is a cross-sectional view and a side view of a chimney upper end showing an example of a conventional chimney;

FIG. 6 is a side view showing an upper end portion of a conventional exterior collective chimney;

FIG. 7 is a perspective view showing a partly broken section of the exterior chimney of FIG. 6;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Exterior-type chimney stack 2 Support structure 3 Smoke stack 3 'cylinder 4 Support beam 5 Smoke collection section 6 Smoke stack 7 Top stage 8 Gap 9 Air inlet gallery 10 Air outlet louver 11 Upflow 12 Smoke stack 13 Ground ( (Base) 14 atmosphere 15 rising atmosphere

Claims (2)

[Claims] 1. A plurality of cylinders are erected on the ground, and a smoke collecting section is provided at an upper end portion for collecting the cylinders. A flue gas tube to be discharged to the outside, and is erected with an interval outside the flue gas tube,
A support structure provided with a support beam for supporting an intermediate portion of the smoke exhaust tube, a top stage surrounding the outer periphery of the smoke collecting section and extending around an inner periphery of an upper end of the support structure, and a vicinity of the support beam An air inlet provided through the side of the support structure for introducing atmospheric air between the smoke stack and the support structure; and an air inlet provided on the top stage and taken up from the air inlet to ascend. And an air outlet for discharging air above the top stage. 2. The exterior stack chimney according to claim 1, wherein the height of the smoke stack is equal to or slightly higher than the height of the support structure.