chimney

Abstract

To provide a chimney capable of being easily applied regardless of whether the chimney is cylindrical or square, or even when the chimney is a cross-sectional oval, and capable of increasing exhaust efficiency of an exhaust flow without requiring an extra flow deflection plate or exhaust guide blade.SOLUTION: A chimney 100 has an outer wall 10, an inner wall 20, and a heat insulating layer 30, and comprises a horizontal draw pipe 200 that guides an exhaust flow to a flue. A groove 24 extending in a direction intersecting an axial direction is provided on an inner surface of the inner wall 20. The inner wall 20 is cylindrical and provided with the groove 24 extending in a spiral direction.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a chimney having a horizontal pipe that guides an exhaust flow sent from an exhaust generation source into a flue formed by the internal space of the inner wall. [Background technology]

[0002] Large chimneys installed inside buildings, such as those constructed to guide and release exhaust flows from exhaust sources such as gas turbines and diesel engines that drive emergency generators, boilers, and industrial waste incinerators, are required to have high exhaust efficiency for the exhaust flow rising up the flue. These chimneys are often cylindrical or rectangular, and generally have a heat insulating layer between an outer wall made of steel plate and an inner wall made of thin steel plate, and are equipped with a horizontal pipe that guides the exhaust flow from the exhaust source to the flue.

[0003] As a measure to improve the exhaust efficiency of chimneys, a prior art example has been proposed in which, for a cylindrical chimney, a deflector plate is placed at the outlet of a horizontal inlet pipe that introduces the exhaust flow sent from the exhaust source into the flue, and the exhaust flow is caused to swirl within the flue by the action of this deflector plate (see Patent Document 1). Another prior art example has been proposed in which the exhaust flow is caused to swirl by the action of spiral exhaust guide vanes arranged within the flue of a cylindrical chimney (see Patent Document 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Jikko No. 63-44667 [Patent Document 2] Publication No. 3226204 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the prior art proposed in Patent Documents 1 and 2 is intended to swirl the exhaust flow along the inner circumferential surface of the flue of a cylindrical chimney, making it difficult to apply it to a rectangular chimney as is. Furthermore, Patent Document 1 requires an extra deflection plate, and Patent Document 2 requires extra exhaust guide vanes, resulting in problems such as high costs and cumbersome construction.

[0006] The present invention has been made in view of the above circumstances, and aims to provide a chimney which can be easily applied to chimneys of any shape, whether cylindrical, rectangular, or even oval in cross section, and which can increase the exhaust efficiency of the exhaust flow rising through the flue, without requiring any extra deflection plates or exhaust guide vanes. [Means for solving the problem]

[0007] The chimney of the present invention is a chimney in which an insulating layer is interposed between an outer wall and an inner wall made of a thin steel plate, and which is equipped with a horizontal pipe that guides the exhaust flow sent out from the exhaust generation source to a flue formed by the internal space of the inner wall, and on the inner surface of the inner wall, grooves extending in a direction intersecting the axial direction of the inner wall are provided in parallel at multiple points in the axial direction.

[0008] Based on the results of a simulation to verify the pressure distribution in the flue (described later), a chimney constructed in this manner was predicted to reduce pressure loss in the exhaust flow through the flue, increase the exhaust velocity, and improve exhaust efficiency. This predicted that a thinner chimney would enable a smaller installation space, thereby enabling a larger building floor area. Furthermore, the chimney of this invention utilizes thin steel plates for its inner wall, and utilizes this to form grooves extending in a specific direction on the inner wall. This not only provides the advantage of easily forming the grooves by performing sheet metal processing such as bending on the inner wall, but also offers cost and construction advantages by eliminating the need for additional deflection plates (described in Patent Document 1) or exhaust guide vanes (described in Patent Document 2). Furthermore, the grooves intersecting the axial direction of the inner wall may be inclined, and the inclination angle of the grooves may be approximately perpendicular to an imaginary plane perpendicular to the axial direction of the cylindrical inner wall, specifically within a range of 0 to 20 degrees. The meaning of "inclination angle of the groove" will be defined in the description of the embodiment to be described later.

[0009] The present invention can be easily applied to cylindrical chimneys, rectangular chimneys, and even chimneys with an oval cross section. For cylindrical chimneys, the thin steel plate constituting the inner wall can be cylindrical, and the grooves can extend in a spiral direction. This configuration makes it easy to uniformly arrange the spiral grooves around the entire circumference of the inner wall, which helps to uniformly distribute the pressure of the exhaust flow through the flue and improve exhaust efficiency. The spiral grooves can be inclined at a substantially right angle, specifically within a range of 0 to 20 degrees, with respect to an imaginary plane perpendicular to the axial direction of the cylindrical inner wall.

[0010] Similarly, for a cylindrical chimney, the inner wall can be formed from the above-mentioned thin steel plate wound in a spiral shape, and the thin steel plates arranged axially on the downstream and upstream sides of the inner wall in the exhaust gas flow direction are connected via a joint formed by a spirally extending seam, and the above-mentioned grooves are provided at multiple locations between two adjacent joints in the axial direction. With this configuration, the spirally wound thin steel plate, the spiral grooves formed in the thin steel plate, and the seam-formed joints combine to easily absorb the influence of the exhaust gas flow temperature by the expansion and contraction action of the inner wall in the axial direction, and also easily suppress bending and deformation of the inner wall. This allows for the use of lightweight and inexpensive rock wool as an insulating layer interposed between the outer and inner walls.

[0011] Next, in the case of a rectangular chimney, it is preferable to adopt a configuration in which the thin steel plate constituting the inner wall is rectangular and the grooves extend in a direction perpendicular to the axis of the inner wall. With this configuration, the grooves extending in a direction perpendicular to the axis of the inner wall act as reinforcing ribs that reinforce the inner wall and help to increase the resistance to flexural deformation of the inner wall made of thin steel plate, which helps to make it easier to use lightweight and inexpensive rock wool as an insulating layer interposed between the outer and inner walls.

[0012] Furthermore, in the case of a chimney having an oval cross section, it is preferable to adopt a configuration in which the thin steel plate constituting the inner wall has an oval cross section and the grooves extend in a direction perpendicular to the axis of the inner wall. With this configuration, the grooves extending in a direction perpendicular to the axis of the inner wall act as reinforcing ribs that reinforce the inner wall and help to increase the resistance to flexural deformation of the inner wall made of thin steel plate, which helps to make it easier to use lightweight and inexpensive rock wool as an insulating layer interposed between the outer and inner walls.

[0013] In the present invention, the groove depth of the grooves is preferably 3 to 5 mm. If the groove depth of the grooves provided on the inner surface of the inner wall made of thin steel plate is too deep, it is predicted that the pressure loss of the exhaust flow will increase, and conversely, if the groove depth is too shallow, it is thought that the significance of providing the grooves will be diluted. Analysis results based on the "simulation to verify the pressure distribution in the flue" described below have predicted that if the groove depth is 3 to 5 mm, the pressure loss will be reduced.

[0014] In the present invention, it is desirable that the groove width of the grooves be 16 to 18 mm and that the pitch between adjacent grooves in the axial direction be 30 to 40 mm. The groove width and the pitch between adjacent grooves should be determined taking into consideration the diameter of the inner wall, etc. For a chimney with an inner wall diameter of about 500 to 1500 mm, it is beneficial to set the groove width to 16 to 18 mm and the pitch between adjacent grooves to 30 to 40 mm. [Effects of the Invention]

[0015] As described above, the chimney according to the present invention is likely to achieve the effect of reducing pressure loss of the exhaust flow through the flue, increasing the exhaust velocity, and improving exhaust efficiency. Based on this, it is possible to use a thin chimney, thereby reducing the installation space required, and thereby increasing the floor area of ​​the building. Furthermore, the chimney according to the present invention takes advantage of the use of thin steel plates for the inner wall, and by utilizing this, grooves extending in a certain direction are formed on the inner wall. This not only has the advantage of easily forming the grooves by performing certain sheet metal processing such as bending on the inner wall, but also has the advantage of eliminating the need for additional deflection plates in Patent Document 1 or exhaust guide vanes in Patent Document 2, as described above, in terms of cost and ease of construction. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a schematic cross-sectional plan view illustrating the basic configuration of a cylindrical chimney according to an embodiment of the present invention. FIG. [Figure 2]FIG. 2 is a partial side view showing the inner wall of the cylindrical chimney of FIG. 1. [Figure 3] 3 is a partially cutaway enlarged view showing part III in FIG. 2. [Figure 4] FIG. 4 is an end view taken along line IV-IV in FIG. 3. [Figure 5] 10(A), 10(B), and 10(C) are cross-sectional views showing various shapes of grooves provided on the inner wall. [Figure 6] FIG. 10 is an explanatory diagram showing comparative images of the analysis results based on the "simulation to verify pressure distribution inside the flue." [Figure 7] FIG. 10 is a schematic cross-sectional plan view illustrating the basic configuration of a rectangular cylindrical chimney according to another embodiment of the present invention. [Figure 8] FIG. 2 is a front view showing the inner surface of a panel-shaped thin steel plate. [Figure 9] FIG. 9 is an end view taken along line IX-IX in FIG. 8. [Figure 10] FIG. 10 is a schematic cross-sectional plan view illustrating the basic configuration of a chimney having an oval cross section according to yet another embodiment of the present invention. [Figure 11] FIG. 2 is a partially cutaway side view showing a portion of an inner wall having an oval cross section. DETAILED DESCRIPTION OF THE INVENTION

[0017] Fig. 1 is a schematic cross-sectional plan view illustrating the basic configuration of a cylindrical chimney according to an embodiment of the present invention. This chimney 100 is installed in a vertical position, for example, in a void in the building framework that serves as a space for constructing the chimney. In this type of chimney 100, the lower end is connected to the outlet of a horizontal inlet pipe (hereinafter referred to as a "horizontal pipe"; not shown in Fig. 1) extending from an exhaust source such as a gas turbine, diesel engine, boiler, or waste incinerator installed in the building, while the upper end protrudes onto the roof of the building or the like.

[0018] The chimney 100 in FIG. 1 has an outer wall 10 made of a shape-retaining steel plate about 4 to 9 mm thick, and an inner wall 20 made of a thin steel plate such as a thin stainless steel plate, with an insulating layer 30 about 50 to 100 mm thick interposed between them. Rock wool is used for the insulating layer 30. Although it is possible to use a zonolite-based calcium silicate board for the insulating layer 30, which has low thermal shrinkage and excellent insulating properties, heat resistance, acid resistance, and abrasion resistance, for example, in consideration of the excellent flexural deformation resistance provided by the geometric characteristics of the cylindrical inner wall 20, it is advantageous to use rock wool alone or in combination with a composite of rock wool and ceramic fiber in the cylindrical chimney 100 from the standpoints of cost, construction, and weight reduction.

[0019] 2 is a partial side view showing the inner wall 20 of a cylindrical chimney, FIG. 3 is a partially cutaway enlarged view showing part III in FIG. 2, and FIG. 4 is an end view taken along line IV-IV in FIG.

[0020] A thin steel plate is used for the cylindrical inner wall 20 shown in FIGS. 2 and 3. A thin stainless steel plate having a thickness of, for example, about 0.6 to 2 mm can be suitably used as this thin steel plate. The diameter of the inner wall 20 is set to about 500 to 1500 mm, and the internal space of this inner wall 20 forms a flue. The cylindrical inner wall 20 is formed of a thin steel plate that is spirally wound into a tubular shape. As shown in FIG. 2, the spirally wound thin steel plate is arranged in the axial direction, with a thin steel plate 21a on the downstream side (upper in the illustrated example) in the exhaust gas flow direction and a thin steel plate 21b on the upstream side (lower in the illustrated example) in the exhaust gas flow direction, connected to each other via a joint 22 formed by a helical groove joint (the exhaust gas flow direction is indicated by arrow F in FIGS. 3 and 4). As shown in Figure 4, in the joint 22 formed by the seam joint, an outward folded piece 22a formed by folding back the end of the thin steel plate 21a on the downstream side in the exhaust gas flow direction outward is slidably interlocked with an outward folded piece 22b formed by folding back the end of the thin steel plate 21b on the upstream side in the exhaust gas flow direction. This interlocking structure allows the joint 22 to absorb the expansion and contraction of the inner wall 20. In addition, in the joint 22 shown in the figure, the inner surfaces of the thin steel plate 21a on the downstream side in the exhaust gas flow direction and the thin steel plate 21b on the upstream side in the exhaust gas flow direction are flush and continuous, allowing rainwater and condensation water to drip down without stagnation, thereby preventing rainwater and condensation water from penetrating the insulation layer 30 and reducing its insulation performance.

[0021] The inner wall 20 is also provided with linear bulges 23 having a mountain-shaped cross section that extend spirally parallel to the joints 22 formed by the above-described groove joints. In this embodiment, the inner wall 20 is made of a thin steel plate that is easily machined, such as sheet metal processing, and therefore the linear bulges 23 can be easily formed. The groove-shaped inner surfaces of the linear bulges 23 are formed as grooves 24 shown in FIG. 3. Therefore, in this inner wall 20, grooves 24 extending in a direction intersecting the axial direction (which coincides with the exhaust gas flow direction F) are provided in parallel at multiple locations along the axial direction of the inner wall 20. In the example shown in FIG. 3, grooves 24 are provided at three locations between two adjacent joints 22, 22. However, grooves 24 may be provided at two or one location between two adjacent joints 22, 22, or at more than three locations.

[0022] 5(A), (B), and (C) show various shapes of the grooves 24 provided in the inner wall 20. The grooves 24 shown in FIG. 5(A) have an arc-shaped cross section, the grooves 24 shown in FIG. 5(B) have an angular cross section, and the grooves 24 shown in FIG. 5(C) have a V-shaped cross section. The cross-sectional shape of the grooves 24 may be a shape other than that shown, such as a semi-elliptical shape. In such grooves 24, it is desirable that the groove depth d is 3 to 5 mm, the groove width w is 16 to 18 mm, and the pitch p between adjacent grooves 24, 24 in the axial direction is 30 to 40 mm. The groove width w of the groove 24 and the pitch p between adjacent grooves should be determined taking into consideration the inner wall diameter D (see Figure 2), and for a chimney with an inner wall diameter of approximately 500 to 1500 mm, it is beneficial to set the groove width to 16 to 18 mm and the pitch p between adjacent grooves to 30 to 40 mm.

[0023] It is known that in a cylindrical chimney 100, the smaller the pressure loss (negative pressure) occurring in the exhaust flow introduced into the flue entrance, the faster the exhaust flow will be discharged through the flue, improving exhaust efficiency. Therefore, the inventors of the present application have examined the pressure distribution occurring in the exhaust flow introduced into the flue from the horizontal pipe for various chimney models. The results are shown in Figure 6.

[0024] Figure 6 is an explanatory diagram showing comparative images of the analysis results based on a "simulation to verify pressure distribution within the flue." Figures 6(A), 6(B), and 6(C) show the pressure distribution in the exhaust flow entering the flue at the connection between the horizontal pipe 200 and the chimney's inner wall 20. Figure 6(A) shows the case where the inner wall 20 has no grooves. Figure 6(B) shows the case where two grooves 24 are provided between two adjacent joints 22. Figure 6(C) shows the case where three grooves 24 are provided between two adjacent joints 22. (See Figure 3 for details of the joints 22 and grooves 24.) The simulation was conducted under conditions of a wind speed of 35 m / s. Negative pressure was observed in the colored regions: blue region I, dark blue region B, green region G, yellow region Y, and orange region O. The negative pressure decreases in the following order: indigo region I > dark blue region B > green region G > yellow region Y > orange region O.

[0025] In Figure 1A, the presence of a blue region I consisting of vortices within the dark blue region B was observed directly above the flue entrance. In Figure 1B, the presence of a dark blue region B consisting of small vortices within the green region G was observed. Furthermore, in Figure 1C, the presence of a dark blue region B with a blurred outline consisting of small vortices within the green region G was observed. These analysis results indicate that the pressure loss at the flue entrance decreases in the following order: when the inner wall 20 has no grooves (Figure 1A), when grooves 24 are provided at two locations between two adjacent joints 22, 22 (Figure 1B), and when grooves 24 are provided at three locations between two adjacent joints 22, 22 (Figure 1C). Therefore, the chimney 100 according to the embodiment exhibits a faster exhaust flow velocity in the flue and improved exhaust efficiency compared to an inner wall 20 without grooves 24. It is also understood that the narrower the mutual pitch p between the adjacent grooves 24, 24, the faster the flow velocity of the exhaust flow in the flue, improving the exhaust efficiency.

[0026] The chimney 100 has been described above, in which a groove 24 extending spirally is provided on a cylindrical inner wall 20. In the chimney 100, the groove 24 may be inclined at a substantially right angle, specifically within a range of 0 to 20 degrees, with respect to an imaginary plane perpendicular to the axial direction of the cylindrical inner wall 20. The closer the inclination angle to the imaginary plane, the more desirable it is. Here, the "inclination angle of the groove 24" is defined as the inclination angle of a linear groove that can be recognized by regarding a short portion of the circumferential direction of the three-dimensional curved groove 24 as a linear groove that approximates the three-dimensional curved groove 24, since the groove 24 represents a three-dimensional curve. As shown in FIG. 2, the axis of the cylindrical inner wall 20 is indicated by Y, the imaginary plane is indicated by P, and the linear groove 24 (see FIG. 3) is indicated by G. The inclination angle is then represented by θ.

[0027] In chimneys 100 that require a large diameter for the cylindrical inner wall 20, such as large chimneys 100 installed inside buildings, the inner wall 20 can be formed by spirally winding a thin steel plate as described above, or by rolling a thin steel plate into a cylindrical shape and welding the butt joints of its circumferential ends together. In the inner wall 20 thus fabricated, it is desirable to provide endless annular grooves perpendicular to the axial direction in multiple parallel positions along the axial direction. This configuration facilitates manufacturing.

[0028] 7 is a schematic cross-sectional plan view illustrating the basic configuration of a rectangular cylindrical chimney 100 according to another embodiment of the present invention. In this chimney 100, an insulating layer 30 having a thickness of about 50 to 100 mm is interposed between an outer wall 10 made of shape-retaining steel plates having a thickness of about 4 to 9 mm assembled into a rectangular cylindrical shape, and an inner wall 20 made of thin steel plate panels, such as thin stainless steel plates having a thickness of about 0.6 to 2 mm, assembled into a rectangular cylindrical shape. A zonolite calcium silicate board is usually used for the insulating layer 30.

[0029] FIG. 8 is a front view showing the inner surface of a panel-shaped thin steel plate 25 used in the rectangular cylindrical inner wall 20, and FIG. 9 is an end view of a portion along line IX-IX in FIG.

[0030] 8 and 9, a large number of laterally extending grooves 26 are formed at intervals in the vertical direction on the inner surface of the panel-shaped thin steel plates 25 that make up the inner wall 20. Therefore, on the inner surface of the rectangular cylindrical inner wall 20 formed by combining panel-shaped thin steel plates 25 into a rectangular cylindrical shape, grooves 26 are formed in multiple locations in the axial direction, extending in a direction that intersects at right angles with the axial direction of the inner wall 20. In this embodiment, too, the grooves 26 can be easily formed because thin steel plates that can be easily machined, such as sheet metal processing, are used for the inner wall 20.

[0031] Thus, even in a rectangular chimney 100 employing an inner wall 20 having multiple parallel grooves 26 extending perpendicular to the axial direction, it is known that the smaller the pressure loss in the exhaust flow introduced into the flue entrance, the faster the exhaust flow velocity in the flue, improving exhaust efficiency. Furthermore, the analysis results based on the "simulation for verifying pressure distribution in the flue" described with reference to FIG. 6 are considered to be similarly applicable to the rectangular chimney 100. Therefore, the rectangular chimney 100 according to this embodiment also has a faster exhaust flow velocity in the flue, improving exhaust efficiency, compared to a rectangular chimney whose inner wall 20 does not have grooves 26. Furthermore, the narrower the pitch between adjacent grooves 26, 26, the faster the exhaust flow velocity in the flue, improving exhaust efficiency.

[0032] Furthermore, in the rectangular chimney 100 according to the embodiment, the grooves 26 provided in the inner wall 20 also function as reinforcing ribs that reinforce the panel-shaped thin steel plate. This allows the inner wall 20 to exhibit excellent resistance to flexural deformation. Normally, to prevent the inner wall from flexing, a zonolite-based calcium silicate board, which is a molded body, is used as the insulating layer, and the inner wall is placed so as to overlap this molded body to prevent the inner wall from flexing. However, as described above, the grooves 26 provided in the inner wall 20 also function as reinforcing ribs that reinforce the panel-shaped thin steel plate, allowing the inner wall 20 to exhibit excellent resistance to flexural deformation. Therefore, instead of the zonolite-based calcium silicate board, rock wool, which is advantageous in terms of cost, ease of installation, and weight reduction, can be used alone or in combination with a ceramic fiber composite for the insulating layer 30.

[0033] In this embodiment, the grooves 26 are shown to have an arc-shaped cross section in the inner wall 20, but the grooves 26 may have an angular or V-shaped cross section. Furthermore, it is desirable that the groove depth is 3 to 5 mm, the groove width is 16 to 18 mm, and the pitch between adjacent grooves 26, 26 in the axial direction is 30 to 40 mm. The groove width of the grooves 26 and the pitch between adjacent grooves should be determined taking into consideration the diameter of the inner wall, etc.

[0034] FIG. 10 is a schematic cross-sectional plan view illustrating the basic configuration of a chimney 100 with an oval cross section according to yet another embodiment of the present invention. The chimney 100 with an oval cross section in the illustration has two flat wall portions 101, 101 of equal width and two semicircular arc wall portions 102, 102 on either side of the flat wall portion 101. This chimney 100 also has an oval outer wall 10 made of a shape-retaining flat steel plate with a thickness of approximately 4 to 9 mm, and an oval inner wall 20 made of a thin steel plate such as a thin stainless steel plate with a thickness of approximately 0.6 to 2 mm. A thermal insulation layer 30 with a thickness of approximately 50 to 100 mm is interposed between the outer wall 10 and the oval cross section. Zonolite calcium silicate boards are typically used for the thermal insulation layer 30.

[0035] 11 is a partially cutaway side view showing a portion of the inner wall 20 having an oval cross section. In this embodiment, the inner wall 20 having an oval cross section has a large number of endless oval grooves 27 formed at intervals in the vertical direction. Therefore, the inner surface of the inner wall 20 having an oval cross section has grooves 27 extending in a direction perpendicular to the axial direction of the inner wall 20 and parallel to the axial direction at multiple locations. In this embodiment, the inner wall 20 is made of a thin steel plate that is easily applicable to machining such as sheet metal processing, so that the grooves 27 can be easily formed.

[0036] Thus, even in a chimney 100 having an oval cross section and an inner wall 20 on which grooves 27 extending perpendicular to the axial direction are provided in parallel at multiple locations along the axial direction, it is known that the smaller the pressure loss in the exhaust flow introduced into the flue entrance, the faster the exhaust flow velocity in the flue, improving exhaust efficiency. Furthermore, the analysis results based on the "simulation for verifying pressure distribution in the flue" described with reference to FIG. 6 are considered to be similarly applicable to the chimney 100 having an oval cross section. Therefore, the chimney 100 having an oval cross section according to this embodiment also has a faster exhaust flow velocity in the flue, improving exhaust efficiency, compared to a chimney having an oval cross section in which the inner wall 20 does not have grooves 27. Furthermore, the narrower the pitch between adjacent grooves 27, 27, the faster the exhaust flow velocity in the flue, improving exhaust efficiency.

[0037] Furthermore, in the chimney 100 having an oval cross section according to the embodiment, the grooves 27 provided in the inner wall 20 also function as reinforcing ribs that reinforce the thin steel plates that form the inner wall 20. This allows the inner wall 20 to exhibit excellent resistance to flexural deformation. Normally, to prevent the inner wall from flexing, a zonolite-based calcium silicate board, which is a molded body, is used as the insulating layer, and the inner wall is arranged so that it overlaps this molded body to prevent the inner wall from flexing. However, as described above, the grooves 26 provided in the inner wall 20 also function as reinforcing ribs that reinforce the panel-shaped thin steel plates, allowing the inner wall 20 to exhibit excellent resistance to flexural deformation. Therefore, instead of the zonolite-based calcium silicate board, rock wool, which is advantageous in terms of cost, ease of installation, and weight reduction, can be used alone or in combination as a composite of rock wool and ceramic fiber for the insulating layer 30.

[0038] In this embodiment, the grooves 27 having an arc-shaped cross section are formed on the inner wall 20, but the grooves 27 may have an angular or V-shaped cross section. It is desirable that the groove depth is 3 to 5 mm, the groove width is 16 to 18 mm, and the pitch between adjacent grooves 27, 27 in the axial direction is 30 to 40 mm. The groove width of the groove 27 and the pitch between adjacent grooves should be determined taking into consideration the diameter of the inner wall, etc. [Explanation of symbols]

[0039] 10 Exterior Wall 20 Inner wall 22 Joint 24, 26, 27 Groove 30 Insulation layer 100 Chimney 200 Horizontal pipe F Exhaust flow direction (axial direction) d Groove depth w Groove width p: groove pitch

Claims

1. A chimney having an insulating layer interposed between an outer wall and an inner wall made of a thin steel plate, and having a horizontal pipe that guides an exhaust flow sent out from an exhaust generation source to a flue formed by an internal space of the inner wall, On the inner surface of the inner wall, grooves extending in a direction intersecting the axial direction of the inner wall are provided in parallel at multiple locations in the axial direction, A chimney characterized in that the thin steel plate constituting the inner wall is rectangular cylindrical, and the grooves extend in a direction perpendicular to the axis of the inner wall.

2. A chimney having an insulating layer interposed between an outer wall and an inner wall made of a thin steel plate, and having a horizontal pipe that guides an exhaust flow sent from an exhaust generating source into a flue formed by the internal space of the inner wall, On the inner surface of the inner wall, grooves extending in a direction intersecting the axial direction of the inner wall are provided in parallel at multiple locations in the axial direction, A chimney characterized in that the thin steel plate constituting the inner wall has an oval cross section, and the grooves extend in a direction perpendicular to the axis of the inner wall.

Images