JP7309569B2 - Heat exchanger - Google Patents

Description

TECHNICAL FIELD The present invention relates to a heat exchanger incorporated in, for example, a boiler of a waste incineration plant.

This type of heat exchanger has a plurality of heat transfer tubes. For example, water is flowed inside the heat transfer tubes, and exhaust gas from the incinerator is flowed outside the heat transfer tubes, so that heat exchange is performed between the water and the exhaust gas through the heat transfer tubes.

FIG. 4 is an explanatory diagram of a conventional heat exchanger. As shown in FIGS. 4(a) and 4(a'), in a heat exchanger 100 having a heat transfer tube structure arranged in a grid pattern, a plurality of heat transfer tubes 101 are arranged in a row direction along the flow direction of the exhaust gas and in the row direction. It has a plurality of straight tube sections 102 arranged in a matrix at a predetermined tube pitch in the orthogonal row direction. One ends of the straight pipe portions 102 adjacent in the row direction are connected by a one-side curved pipe portion 103 . The other ends of the straight tube portions 102 adjacent in the row direction are connected by the other side bent tube portion 104 . In addition to the advantage of having a simple structure, such a grid arrangement has the advantage of preventing dust, which is an adherent substance contained in the exhaust gas, from clogging the straight pipe sections adjacent to each other in the row direction. Therefore, it is commonly used as a heat transfer tube structure for boilers.

4(b) and 4(b'), and 4(c) and 4(c'), the staggered arrangement (for example, , see Patent Documents 1 and 2). In the case of the staggered arrangement, as a method of connecting the straight pipe portions 102, the straight pipe portions 102 positioned in the exhaust gas flow direction are connected by curved pipe portions 103 and 104 along the exhaust gas flow direction (FIG. 4B). and (b')), and one that is connected by curved pipe portions 103 and 104 obliquely inclined with respect to the exhaust gas flow direction (see FIGS. 4(c) and (c')).

As one means of shortening the pipe pitch in the exhaust gas flow direction, as shown in FIGS. There is a method in which a plurality of curved pipe portions 113, 114, and 115 that increase in size are collectively connected (see, for example, Patent Document 3).

As another means for shortening the pipe pitch in the exhaust gas flow direction, as shown in FIGS. (See Patent Document 4, for example). The straight pipe portion 122 and the header 123 are joined by welding. In this case, the pipe pitch can be shortened to the limit of the gap required for welding the two straight pipe portions 122 arranged in the exhaust gas flow direction with respect to the header 123 .

Furthermore, as shown in FIGS. 4(f) and 4(f'), there is also a technique in which a U-shaped cast iron header 133 is used in place of the cylindrical header 123 (for example, Patent Document 5: ).

JP 2018-80852 A JP-A-9-26102 Japanese Patent Application Laid-Open No. 2001-147093 JP-A-2000-18501 JP 2017-9265 A

4(a) and 4(a'), due to restrictions on the minimum bending radii for manufacturing each of the one-side curved tube portion 103 and the other-side curved tube portion 104, the exhaust gas flow direction (row direction) ), the pipe pitch of the straight pipe portion 102 is restricted. Therefore, it is difficult to shorten the pipe pitch of the straight pipe portions 102 in the flow direction of the exhaust gas in the heat exchanger with the grid arrangement, and it is difficult to make the heat exchanger compact.

4(b) and (b') and FIGS. 4(c) and (c') can be made more compact than those shown in FIGS. 4(a) and (a'). However, when the plurality of straight pipe portions 102 are viewed in the exhaust gas flow direction, the straight pipe portions 102 of the next row are positioned between the straight pipe portions 102 adjacent in the column direction in a certain row. Therefore, the dust in the exhaust gas adheres and accumulates on the straight pipe portions 102 in the next row, and the space between the straight pipe portions 102 adjacent in the column direction in a certain row and the straight pipe portions 102 in the next row becomes There is a problem that the flow path in the flow direction of the exhaust gas is clogged by the grown dust and the heat exchange rate is deteriorated.

4(d) and (d'), the bending dimension of the outermost bent pipe portion 115 among the plurality of bent pipe portions 113, 114, and 115 is extremely large to achieve compactness. In addition, the dead space increases, and the minimum bending radius of the innermost bent pipe portion 113 is restricted, so the pipe pitch of the straight pipe portion 112 in the flow direction of the exhaust gas cannot be shortened so much.

4(e) and 4(e'), the cylindrical header 123 must be processed separately, and welding the straight pipe portion 122 and the header 123 is time-consuming. Also, there is the problem of increased costs required for welding.

4(f) and 4(f'), in the case of mass production, the use of the header 133 made of cast metal can reduce the cost to some extent, but the processing cost and welding of the header 133 are still required. The problem of increased costs cannot be resolved.

The present invention has been made in view of the above problems. An object of the present invention is to provide a heat exchanger capable of shortening the tube pitch in the direction of flow of a fluid flowing outside heat transfer tubes without clogging a flow path in the direction of flow.

The characteristic configuration of the heat exchanger according to the present invention for solving the above problems is
A plurality of heat transfer tubes are provided, and one of the two fluids with different temperatures is caused to flow inside the heat transfer tubes, and the other fluid is allowed to flow outside the heat transfer tubes, so that the two fluids through the heat transfer tubes A heat exchanger configured to exchange heat between fluids,
The heat transfer tube is
A matrix of M rows and N columns (M is an integer of 3 or more and N is an integer of 2 or more) at a predetermined tube pitch in the row direction along the flow direction of the other fluid and in the column direction orthogonal to the row direction. a plurality of main sections arranged in
m-th row n-th column (m=1, . a one-side tube portion that connects one end portions of the
a other side pipe portion connecting the other end portions of the main pipe portion of the (m+1)th row and the (n+1)th column and the main pipe portion of the (m+2)th row and the nth column among the plurality of main pipe portions;
to include

In the heat exchanger of this configuration, M rows and N columns (M is an integer of 3 or more, N is An integer of 2 or more) is arranged in a matrix. According to this arrangement, when the plurality of main pipe portions are viewed in the other fluid flow direction, the main pipe portions in the next row are not positioned between the main pipe portions adjacent in the column direction in a given row. Therefore, even if the fluid flowing to the outside of the heat transfer tubes contains an adhesive substance, the fluid flowing to the outside of the heat transfer tubes does not clog the flow path due to the adhesive substances.

In addition, in the heat exchanger of this configuration, one end of the main pipe portion of the m-th row, n-th column and the main pipe portion of the (m+1)-th row, (n+1)-th column are connected to each other by the one side pipe portion. Since one side pipe portion does not connect one ends of the main pipe portions adjacent in the row direction in the same column, the pipe pitch of the main pipe portions adjacent in the row direction in the same column can be changed if the adjacent main pipe portions contact each other. Even if it is made as small as possible, it is possible to connect one ends of the main pipe portion at the m-th row and n-th column with the main pipe portion at the (m+1)-th row and the (n+1)-th column. Similarly, in the heat exchanger of this configuration, the other end portions of the (m+1)th row and (n+1)th column main pipe portion and the (m+2)th row and nth column main pipe portion are connected to each other by the other side pipe portion. be done. Since the other side pipe portion does not connect the other ends of the main pipe portions that are adjacent in the row direction in the same column, the pipe pitch of the main pipe portions that are adjacent in the row direction in the same column is assumed to be Even if they are made small enough to contact each other, the other end portions of the (m+1)th row and (n+1)th column main pipe portion and the (m+2)th row and nth column main pipe portion can be connected to each other. Therefore, theoretically, the tube pitch in the flow direction (row direction) of the fluid flowing outside the heat transfer tubes can be shortened until the main tube portions adjacent to each other in the row direction come into contact with each other, thereby making the heat exchanger more compact. can be planned.

In the heat exchanger according to the present invention,
The main pipe portion has a shape that extends linearly in a direction intersecting the flow direction of the other fluid, and both the one side pipe portion and the other side pipe portion have a shape that curves with a predetermined bending radius. Preferably.

According to the heat exchanger of this configuration, by performing a required bending process on one long pipe, the main pipe portion has a shape that extends linearly and one side has a shape that curves with a predetermined bending radius. The heat transfer tube can be configured so that the tube portion and the other side tube portion are seamlessly connected, and the heat transfer tube is configured by joining the header and the straight tube portion by welding. e'), and compared to those shown in FIGS.

In the heat exchanger according to the present invention,
When the pipe pitch in the row direction of the plurality of main pipe portions is P, and the pipe outer diameter of the plurality of main pipe portions is D, it is preferable to satisfy the relationship D≤P≤2.5D.

According to the heat exchanger of this configuration, the row-direction pipe pitch P in the plurality of main pipe portions and the pipe outer diameter D of the plurality of main pipe portions satisfy the relationship D≦P≦2.5D. Therefore, it is possible to make the heat exchanger more compact than the conventional heat exchanger 100 (see FIGS. 4(a) and 4(a')) having P=3D. 4(b) and 4(b'), 4(c) and c') can be much more compact than the staggered heat exchanger shown in FIG.

FIG. 1 shows a heat exchanger according to one embodiment of the present invention, (a) is an external perspective view seen from the front side, and (b) is an external perspective view seen from the back side. FIG. 2 is a schematic diagram showing a generalized front view arrangement of heat exchangers according to an embodiment of the present invention. FIG. 3 is an external perspective view of a heat transfer tube that constitutes a heat exchanger according to one embodiment of the present invention. FIG. 4 is an explanatory diagram of a conventional heat exchanger.

The present invention will be described below with reference to FIGS. 1 to 3. FIG. In the following embodiments, a heat exchanger incorporated in a boiler of a waste incineration facility will be described as an example. However, the present invention is not intended to be limited to the embodiments described below or the configurations described in the drawings.

<Overall composition>
FIG. 1 shows a heat exchanger according to one embodiment of the present invention, (a) is an external perspective view seen from the front side, and (b) is an external perspective view seen from the back side. A heat exchanger 1 shown in FIGS. and the other side support member 30 that supports the other side (back side) of the heat tube 10 . Then, for example, water (corresponding to "one fluid" of the present invention) is flowed inside the heat transfer tube 10, and exhaust gas from an incinerator (not shown) ("the other fluid" of the present invention) is flowed outside the heat transfer tube 10. ) is flowed from the upper side to the lower side in FIGS. generate steam.

In this embodiment, the support structure for supporting the plurality of heat transfer tubes 10 using the plate-shaped one-side support member 20 and the other-side support member 30 is illustrated, but the mutual positions of the plurality of heat transfer tubes 10 are For example, a pair of support plates are arranged so as to sandwich the plurality of straight pipe portions 40 from both sides, and these support plates are fastened with fastening means such as bolts to attach the plurality of heat transfer tubes 10 to each other. A support structure that fixes the position may be employed.

The plurality of heat transfer tubes 10 includes a plurality of straight pipe portions 40 (corresponding to the "main pipe portion" of the present invention) and a plurality of one-side curved pipe portions 50 (corresponding to the "one-side pipe portion" of the present invention. ) and a plurality of other-side bent pipe portions 60 (corresponding to the “other-side pipe portion” of the present invention).

<Straight pipe part>
FIG. 2 is a schematic diagram showing a generalized front view arrangement of heat exchangers according to an embodiment of the present invention. As shown in the schematic diagram of FIG. 2, the straight pipe portions 40 are arranged in predetermined directions in the row direction along the flow direction of the exhaust gas generated by burning the waste in the incinerator and in the column direction perpendicular to the row direction. They are arranged in a matrix of M rows and N columns (M is an integer of 3 or more and N is an integer of 2 or more) at a tube pitch.

<One side bend>
The one-side bent pipe portion 50 includes the straight pipe portion 40 of the m-th row, n-th column (m=1, . . . , M, n=1, . . . , N) and the (m+1)-th row, ) are connected to the straight tube portions 40 of the row.

<Other side bending part>
The other-side bent pipe portion 60 connects the other end portions of the straight pipe portion 40 in the (m+1)th row and the (n+1)th column and the straight pipe portion 40 in the (m+2)th row and the nth column.

<Manufacture of heat transfer tubes>
FIG. 3 is an external perspective view of a heat transfer tube that constitutes a heat exchanger according to one embodiment of the present invention. The heat transfer tube 10 is formed by bending a single long tube 180° in a state inclined at a predetermined obtuse angle θ in the depression direction with respect to the horizontal plane W, and making the bent portion a U shape. It is referred to as the other side bent tube portion 60 . In this way, the other-side curved tube portion 60 is formed into a shape curved with a predetermined bending radius.

Next, the long pipe is fed by a fixed distance, and this feed portion is defined as the straight pipe portion 40 . Thus, the straight pipe portion 40 is formed in a shape extending linearly in a direction intersecting (perpendicular to) the flow direction of the exhaust gas.

After that, the pipe itself is again bent at a predetermined obtuse angle θ in the depression direction with respect to the horizontal plane W, and then bent 180°. . In this way, the one-side curved tube portion 50 is formed into a shape curved with a predetermined bending radius.

By repeating the above operations a plurality of times, as shown in FIG. The pipe portion 60 can be formed into a shape that is seamlessly continuous in a meandering manner. Since the bending here does not involve twisting, stress fatigue in the bent portions (the one-side bent pipe portion 50 and the other-side bent pipe portion 60) is reduced, and the headers 123 and 133 and the straight pipe portion 122 are joined by welding to form a heat transfer tube, compared to those shown in FIGS. , and the manufacturing cost can be kept low.

In the heat exchanger 1 configured as described above, as shown in FIGS. 1(a) and 1(b) and FIG. A plurality of straight pipe portions 40 are arranged in a matrix of M rows and N columns (M is an integer of 3 or more and N is an integer of 2 or more) at a predetermined pipe pitch in the column direction. According to this arrangement, when the plurality of straight pipe portions 40 are viewed in the exhaust gas flow direction, the straight pipe portions 40 in the next row are positioned between the straight pipe portions 40 adjacent in the column direction in a certain row. Therefore, even if the exhaust gas contains dust, which is an adherent substance, the dust does not clog the flow path of the exhaust gas.

In the heat exchanger 1 , one end of the straight pipe portion 40 in the m-th row and n-th column and one end of the straight pipe portion 40 in the (m+1)-th row and the (n+1)-th column are connected by the one-side curved pipe portion 50 . be done. Since the one-side curved pipe portion 50 does not connect one ends of the straight pipe portions 40 adjacent in the row direction in the same column, the pipe pitch of the straight pipe portions 40 adjacent in the row direction in the same column Even if the adjacent straight pipe portions 40 are made small enough to contact each other, one ends of the straight pipe portion 40 in the m-th row and the n-th column and the straight pipe portion 40 in the (m+1)-th row and the (n+1)-th column are connected to each other. be able to.

Similarly, in the heat exchanger 1, the straight pipe portion 40 of the (m+1)-th row and the (n+1)-th column and the straight pipe portion 40 of the (m+2)-th row and the n-th column are connected to each other at the other end. connected by a section 60; Since the other-side curved pipe portion 60 does not connect the other ends of the straight pipe portions 40 adjacent in the row direction in the same column, the pipe pitch of the straight pipe portions 40 adjacent in the row direction in the same column is temporarily set to Even if the adjacent straight pipe portions 40 are made small enough to contact each other, the other end portion of the straight pipe portion 40 of the (m+1)th row and the (n+1)th column and the straight pipe portion 40 of the (m+2)th row and the nth column can be linked together.

Therefore, theoretically, the pipe pitch in the exhaust gas flow direction (row direction) can be shortened until the straight pipe portions 40 adjacent to each other in the row direction come into contact with each other, so that the heat exchanger 1 can be made compact. .

In the heat exchanger 1 of the present embodiment, as shown in FIG. 2, when P is the pipe pitch in the row direction of the plurality of straight pipe portions 40 and D is the pipe outer diameter of the plurality of straight pipe portions, D It is preferable to satisfy the relationship ≦P≦2.5D. In this way, it is possible to make the heat exchanger more compact than the conventional grid pattern heat exchanger 100 (see FIGS. 4A and 4A') in which P=3D. 4(b) and 4(b') and FIG. and (c') can be much more compact than the staggered heat exchanger shown in (c').

As described above, the heat exchanger of the present invention has been described based on one embodiment, but the present invention is not limited to the configuration described in the above embodiment, and the configuration can be changed as appropriate without departing from the scope of the invention. It is something that can be done.

(another embodiment)
In the above embodiment, the straight pipe portion 40 having a shape extending linearly is exemplified as the main pipe portion of the present invention. may be in the form of Further, in the above-described embodiment, the one-side curved tube portion 50 and the other-side curved tube portion 60 having a shape curved with a predetermined bending radius are exemplified as the one-side tube portion and the other-side tube portion of the present invention, respectively. However, it does not necessarily have to be curved, and may be bent in a U-shape.

The heat exchanger of the present invention can be used, for example, by incorporating it into a boiler of a waste incineration facility to exchange heat with exhaust gas.

1 heat exchanger 10 heat transfer tube 20 one side support member 30 other side support member 40 straight pipe portion (main pipe portion)
50 One side bent tube (one side tube)
60 Other side bent pipe (other side pipe)

Claims (3)

A plurality of heat transfer tubes are provided, one of two fluids having different temperatures is caused to flow inside the heat transfer tubes, and the other fluid containing an adhesive substance is caused to flow outside the heat transfer tubes. A heat exchanger configured to exchange heat between the two fluids via heat tubes,
The heat transfer tube is
A matrix of M rows and N columns (M is an integer of 3 or more and N is an integer of 2 or more) at a predetermined tube pitch in the row direction along the flow direction of the other fluid and in the column direction orthogonal to the row direction. a plurality of main sections arranged in
m-th row n-th column (m=1, . a one-side tube portion that connects one end portions of the
a other side pipe portion connecting the other end portions of the main pipe portion of the (m+1)th row and the (n+1)th column and the main pipe portion of the (m+2)th row and the nth column among the plurality of main pipe portions;
including
When the plurality of main pipe portions are viewed in the flow direction of the other fluid, between the main pipe portion of the m-th row, n-th column and the main pipe portion of the m-th row, n-th column in the plurality of main pipe portions. A heat exchanger configured such that the main pipe portion of the (m+1)th row and (n+1)th column is not positioned . The main pipe portion has a shape that extends linearly in a direction intersecting the flow direction of the other fluid, and both the one side pipe portion and the other side pipe portion have a shape that curves with a predetermined bending radius. A heat exchanger according to claim 1. 3. The set forth in claim 1 or 2, wherein a relationship of D≤P≤2.5D is satisfied, where P is the pipe pitch in the row direction in the plurality of main pipe portions and D is the pipe outer diameter of the plurality of main pipe portions. A heat exchanger as described.

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