Patent Grant
11215400
The present invention relates to a heat exchanger.
This application claims priority based on JP 2017-195367 A filed in Japan on Oct. 5, 2017, the contents of which are incorporated herein by reference.
As a heat exchanger, there is a multitube heat exchanger which includes an outer cylinder, a tube plate partitioning the inside of the outer cylinder into a tube-interior fluid chamber and a tube-exterior fluid chamber, and a plurality of heat transfer tubes fixed to the tube plate and arranged in the tube-exterior fluid chamber. In such a heat exchanger, for example, there is a case where the plurality of heat transfer tubes are supplied with a heating medium and a corrosive fluid is flowed into the tube-exterior fluid chamber in the outer cylinder to heat the corrosive fluid. In a case where a member defining the tube-exterior fluid chamber is formed of, for example, carbon steel, when a corrosive fluid flows into the tube-exterior fluid chamber, the member defining the tube-exterior fluid chamber is corroded. Therefore, the following patent documents disclose a multitube heat exchanger that suppresses corrosion of a member defining a tube-exterior fluid chamber.
A tube plate of this heat exchanger includes a base material formed of carbon steel and a surface material formed of stainless steel. The surface material is disposed on the surface of the base material on the tube-exterior fluid chamber side.
Patent Document 1: JP 5433461 B
In the heat exchanger described in Patent Document 1, it is possible to suppress corrosion of the tube plate while reducing the amount of use of expensive materials. However, in this heat exchanger, a thermal elongation difference between the base material and the surface material occurs during use of the heat exchanger due to a difference between a linear expansion coefficient of carbon steel and a linear expansion coefficient of stainless steel. Therefore, the durability of the heat exchanger is reduced unless the thermal elongation difference between materials is taken into consideration.
An object of the present invention is to provide a heat exchanger capable of suppressing an increase in manufacturing cost and progression of corrosion, and further suppressing deterioration in durability.
In order to solve the above problem, the following configuration is adopted.
According to a first aspect of the present invention, a heat exchanger includes: an outer cylinder having a cylindrical shape with both ends closed; a tube plate partitioning, at a position close to a first end of the both ends, an inside of the outer cylinder into a tube-interior fluid chamber on a side where the first end is located and a tube-exterior fluid chamber on a side where a second end is located; a plurality of heat transfer tubes arranged in the tube-exterior fluid chamber and including at least one end that is fixed to the tube plate and faces the tube-interior fluid chamber; and a partition wall partitioning the tube-exterior fluid chamber into a first tube chamber, in which an inlet side tube group is present as a collection of inlet side tube sections extending from inlet ends of the plurality of heat transfer tubes, and a second tube chamber, in which an outlet side tube group is present as a collection of outlet side tube sections extending from outlet ends of the plurality of heat transfer tubes. The tube plate includes a tube plate base material to which end sections of the plurality of heat transfer tubes are fixed, a first backplate covering a surface of the tube plate base material on a side where the first tube chamber is located, and a fastener that includes at least a shaft section and is configured to fix the first backplate to the tube plate base material. The first backplate includes heat transfer tube insertion holes through which the plurality of heat transfer tubes are inserted and an insertion hole through which the shaft section is loosely inserted, and the first backplate is joined to an end section of the second partition wall on the side where the first end is located. The partition wall, the first backplate, and the fastener are formed of a material having a higher corrosion resistance than the tube plate base material.
According to this first aspect, a first backplate formed of a material having a higher corrosion resistance than the tube plate base material is fixed to the surface of the tube plate base material on the first tube chamber side. Therefore, when the temperature of the corrosive fluid flowing in the first tube chamber is higher than that of the corrosive fluid flowing in the second tube chamber, progression of corrosion by the surface of the tube plate base material on the first tube chamber side contacting the corrosive fluid can be suppressed. Further, the first backplate is connected to the tube plate base material by a screw fastener and is joined to the end section of the second partition wall on the side where the first end is located. That is, the first backplate is joined only to the second partition wall, not to the outer cylinder, and is fixed to the outer plate base material only by a fastener in which the shaft section is loosely inserted into the insertion hole. Therefore, even in a case where a thermal elongation difference occurs between the tube plate base material and the outer cylinder and the first backplate, when the force acting on the first backplate due to the thermal elongation difference exceeds the fixing force of the fastener, the first backplate can be slightly displaced with respect to the fastener. Therefore, it is possible to prevent excessive stress from being applied to the first backplate due to the thermal elongation difference.
Therefore, it is possible to suppress an increase in manufacturing cost and progression of corrosion, and to suppress a decrease in durability.
According to a second aspect of the present invention, the heat exchanger according to the first aspect may include: an inner cylinder arranged in the tube-exterior fluid chamber and covering the plurality of heat transfer tubes and the second partition wall; a space partition member that is disposed between the outer cylinder and the inner cylinder and that partitions a space between the outer cylinder and the inner cylinder on the side where the first tube chamber is located into the side where the first end is located and the side where the second end is located; a first nozzle stub provided in the outer cylinder at a position closer to the second end than to the space partition member on the side where the first tube chamber is located with respect to the partition wall or at a position on a side where the second tube chamber is located with respect to the partition wall; and a second nozzle stub provided in the outer cylinder on the side where the first tube chamber is located with respect to the partition wall and at a position between the space partition member and the tube plate. The inner cylinder may be open on the side where the first end is located and closed on the side where the second end is located. The partition wall may be joined to the inner cylinder to divide the inner cylinder into two sections in a radial direction to form the first tube chamber and the second tube chamber. The space partition member may be joined to an outer peripheral surface of the inner cylinder and displaceable with respect to an inner peripheral surface of the outer cylinder without being joined to the inner peripheral surface of the outer cylinder. The inner cylinder and the space partition member may be formed of a material having a higher corrosion resistance than the tube plate base material.
According to the second aspect, the inner cylinder and the space partition member are formed of a material having a higher corrosion resistance than the tube plate base material. Therefore, even when a high-temperature corrosive fluid flows in the first tube chamber, corrosion of the inner cylinder and the space partition member can be suppressed. Further, the inner cylinder and the second partition wall are joined, and the space partition member is not joined to the outer cylinder. Therefore, even when a thermal elongation difference occurs between the inner cylinder and the space partition member with respect to the outer cylinder, stress can be prevented from being applied to the space partition member and the inner cylinder.
According to a third aspect of the present invention, the heat exchanger according to the second aspect may include a second backplate that is disposed to cover a region between the space partition member and the tube plate on the side where the first tube chamber is located in the inner peripheral surface of the outer cylinder and that is formed of a material having a higher corrosion resistance than the outer cylinder.
In this third aspect, the region between the space partition member and the tube plate, in which the second nozzle stub is provided, is covered with the second backplate in the inner peripheral surface of the outer cylinder. Therefore, when a high-temperature corrosive fluid flows in or out of the second nozzle, the high-temperature corrosive fluid can be prevented from contacting the inner peripheral surface of the outer cylinder.
According to a fourth aspect of the present invention, the heat exchanger according to the second or third aspect may include a first seal that is disposed to extend between the inner peripheral surface of the outer cylinder and either one of a surface, on the side where the first end is located, and a surface, on the side where the second end is located, of the space partition member and that closes a gap generated between the space partition member and the inner peripheral surface of the outer cylinder while allowing the space partition member to be displaceable with respect to the outer cylinder.
According to the fourth aspect, even when a gap is formed between the space partition member and the outer cylinder, the gap is closed by the first seal, so that the corrosive fluid can be prevented from flowing through the gap.
According to a fifth aspect of the present invention, the heat exchanger according to any one of the second to fourth aspects may include a second seal that is disposed to extend between the inner peripheral surface of the outer cylinder and either one of a surface, on the side where the first tube chamber is located, and a surface, on the side where the second tube chamber is located, of the partition wall and that closes a gap generated between the partition wall and the inner peripheral surface of the outer cylinder while allowing the partition wall to be displaceable with respect to the outer cylinder.
According to the fifth aspect, even when a gap is formed between the partition wall and the outer cylinder, since the gap between the partition wall and the outer cylinder is closed while the partition wall can be displaced with respect to the outer cylinder by the second seal, it is possible to prevent the flow of corrosive fluid between the first tube chamber and the second tube chamber.
According to a sixth aspect of the present invention, the second backplate according to the third aspect may be divided into a plurality of sections along the inner peripheral surface of the outer cylinder.
In the sixth embodiment, since the inner peripheral surface of the outer cylinder is covered with the second backplate divided into a plurality of sections, for example, deformation of the second backplate caused by a thermal elongation difference in the axial direction between the outer cylinder and the second backplate can be suppressed.
According to a seventh aspect of the present invention, the second nozzle stub according to any one of the second to sixth aspects may be formed of a material having a higher corrosion resistance than the outer cylinder.
In the seventh aspect, since the first nozzle stub is formed of a material having a high corrosion resistance, it is possible to suppress progression of corrosion of the first nozzle stub in contact with the corrosive fluid when the high-temperature corrosive fluid flows in and out through the first nozzle stub.
According to an eighth aspect of the present invention, the fastener according to any one of the first to seventh aspects may include a washer that has an inner diameter larger than an outer diameter of the shaft section and smaller than an inner diameter of the insertion hole and that has an outer diameter larger than an inner diameter of the insertion hole.
In the eighth aspect, since the washer is provided, it is possible to prevent the corrosive fluid from entering between the first backplate and the tube plate through the insertion hole.
According to a ninth aspect of the present invention, the first seal according to the fourth aspect may be formed in a sheet shape elastically deformed so that a concave surface is disposed on a side in which pressure is relatively high.
According to a tenth aspect of the present invention, the second seal according to the fifth aspect may be formed in a sheet shape elastically deformed so that a concave surface is disposed on a side in which pressure is relatively high.
In the ninth and tenth aspects, the first seal and the second seal formed in the shape of a sheet are elastically deformed to close the gap. Therefore, even when the size of the gap changes, it is possible to suppress deterioration of the sealing performance.
According to the above-described heat exchanger, it is possible to suppress an increase in manufacturing cost and progression of corrosion, and further to suppress a decrease in durability.
Next, a heat exchanger according to a first embodiment of the present invention will be described with reference to the drawings.
As illustrated in
The outer cylinder 10 includes a trunk part 11 that is cylindrical centered around the axis X, and a first end plate 12 and a second end plate 13, which are connected to the ends of the trunk part 11. The trunk part 11 includes a first nozzle stub 14a and a second nozzle stub 14b. The first nozzle stub 14a communicates a second tube chamber 15b described later with the outside of the outer cylinder 10, and the second nozzle stub 14b communicates a first tube chamber 15a described later with the outside of the outer cylinder 10.
In the following description, a direction in which the axis X extends is referred to as an axial direction Dx, and one side of the axial direction Dx is referred to as a first end side D1, and the other side thereof is referred to as a second end side D2.
The first end plate 12 is connected to the end of the trunk part 11 on the first end side D1, and closes the opening of the trunk part 11 on the first end side D1. The first end plate 12 has a curved surface whose inner surface is smoothly recessed in a concave shape to a side away from the second end plate 13, that is, to the first end side D1. The first end plate 12 is provided with a tube-interior side inlet nozzle 16a and a tube-interior side outlet nozzle 16b. The tube-interior side inlet nozzle 16a allows a tube-interior fluid Fi as a heat medium to flow into the inside of the tube-interior fluid chamber 17 from the outside of the outer cylinder 10. The tube-interior side outlet nozzle 16b allows the tube-interior fluid Fi to flow out from the inside of the tube-interior fluid chamber 17 to the outside of the outer cylinder 10.
The second end plate 13 is connected to the end of the trunk part 11 on the second end side D2, and closes the opening of the trunk part 11 on the second end side D2. The second end plate 13 has a curved surface whose inner surface is smoothly recessed in a concave shape to a side away from the first end plate 12, that is, to the second end side D2. The outer cylinder 10 is provided with the trunk part 11, the first end plate 12, and the second end plate 13 to form a cylindrical shape with both ends closed. In the first end plate 12, an endmost section on the first end side D1 forms a first end 10a of the outer cylinder 10. In the second end plate 13, an endmost section on the second end side D2 forms a second end 10b of the outer cylinder 10.
The tube plate 20 partitions the inside of the outer cylinder 10 into a tube-interior fluid chamber 17 on the first end side D1 and a tube-exterior fluid chamber 18 on the second end side D2 at a position closer to the first end side D1 than to the center of the outer cylinder 10 in the axial direction Dx. More specifically, the tube plate 20 is formed at the boundary between the first end plate 12 and the trunk part 11 to partition the tube-interior fluid chamber 17 and the tube-exterior fluid chamber 18. The tube plate 20 according to the present embodiment is substantially disk-shaped. The tube plate 20 is formed with a plurality of tube holes 21 extending in the axial direction Dx. An inlet end 31 and an outlet end 32 of the heat transfer tube 30 are inserted into and fixed to the tube holes 21.
The heat transfer tube 30 is formed in a U-shape having a straight-tube section 33 and a curved-tube section 34. The straight-tube section 33 includes an inlet side tube section 33a and an outlet side tube section 33b. The inlet side tube section 33a has an inlet end 31 at one end thereof and is connected to the curved-tube section 34 at the other end thereof. The inlet end 31 of the inlet side tube section 33a serves as an inlet into which the tube-interior fluid H flows into the heat transfer tube 30. The outlet side tube section 33b has an outlet end 32 at one end thereof and is connected to the curved-tube section 34 at the other end thereof. The outlet end 32 of the outlet side tube section 33b serves as an outlet through which the tube-interior fluid Fi flows out from the inside of the heat transfer tube 30. Both the inlet side tube section 33a and the outlet side tube section 33b extend in the axial direction Dx. The inlet end 31 and the outlet end 32 are respectively fixed to the tube plate 20.
The inlet end 31 is fixed while inserted into a tube hole 21 formed in one semicircle (upper half circle in
The inner cylinder 40 is disposed inside the outer cylinder 10. More specifically, the inner cylinder 40 is formed so as to surround the straight-tube section 33 and the curved-tube section 34 from the outside in the tube-exterior fluid chamber 18. The inner cylinder 40 includes a trunk part 41, an end plate 42, and a space partition member 43. The trunk part 41 is formed in a cylindrical shape centered around the axis X. The trunk part 41 is separated from the inner surface of the trunk part 11 of the outer cylinder 10 toward the side closer to the axis X. In other words, the trunk part 41 has an outer diameter smaller than the inner diameter of the trunk part 11 of the outer cylinder 10.
The end plate 42 is connected to the second end side D2 of the trunk part 41. That is, the end plate 42 closes the opening of the second end side D2 of the trunk part 41. The end plate 42 has an inner surface which is smoothly recessed to the second end side D2. In particular, the inner surface of the end plate 42 smoothly curves along the largest curved-tube section 34a having the largest radius of curvature among the curved-tube sections 34. The outer surface of the end plate 42 is separated from the inner surface of the second end plate 13 of the outer cylinder 10 toward the inside of the second end plate 13.
On the other hand, the first end side D1 of the trunk part 41 is open. That is, the end plate or the like is not provided at the end of the first end side D1 of the trunk part 41. The end (in other words, an opening) of the first end side D1 of the trunk part 41 according to the present embodiment is located between the second nozzle stub 14b and the tube plate 20.
The tube support plate 80 partitions the inside of the inner cylinder 40 into a curved-tube chamber 19, in which the curved-tube section 34 is arranged, and other chambers. The tube support plate 80 is formed in a flat plate shape extending in a direction intersecting the axis X. A plurality of tube holes 81 through which the heat transfer tubes 30 pass in the axial direction Dx are formed in the tube support plate 80. The heat transfer tubes 30 are inserted through the tube holes 81 and supported by the tube support plate 80.
As illustrated in
The space partition member 43 is joined to the outer peripheral surface 41a of the trunk part 41 of the inner cylinder 40 by welding or the like. On the other hand, the space partition member 43 is not joined to the inner peripheral surface of the outer cylinder 10 by welding or the like, but is instead provided with a first seal 44 configured to close a gap generated between the space partition member 43 and the inner peripheral surface 10c of the outer cylinder 10.
As the first seal 44, a so-called lamiflex seal plate can be used. As illustrated in
As illustrated in
The second partition wall 60, together with the inner cylinder 40 and the space partition member 43, partitions the inside of the tube-exterior fluid chamber 18 into a first tube chamber 15a and a second tube chamber 15b. An inlet side tube group 33Ga, which is a collection of the inlet side tube sections 33a described above, is arranged in the first tube chamber 15a, and an outlet side tube group 33Gb, which is a collection of the outlet side tube sections 33b described above, is arranged in the second tube chamber 15b. The second partition wall 60 according to the present embodiment is located on the axis X and is formed in a flat plate shape extending in the horizontal direction.
As illustrated in
As illustrated in
Both edge sections 62a of the large width section 62 in the width direction centered around the axis X are not fixed to the inner peripheral surface 10c of the outer cylinder 10. The width of the large width section 62 is slightly smaller than the inner diameter of the outer cylinder 10. The second seal 64 is attached to both edges 62a of the large width section 62. The gap between the second partition wall 60 and the inner peripheral surface of the outer cylinder 10 is closed by the second seal 64.
As illustrated in
As illustrated in
The first baffles 70a adjacent to each other in the axial direction Dx have windows 72 at positions shifted from each other when viewed from the axial direction Dx. Here, the tube-exterior fluid Fo flowing in the axial direction Dx through the window section 72 of one first baffle 70a is deflected by a section other than the window section 72, of a first baffle 70a adjacent to the first baffle 70a in the axial direction Dx, and flows in the direction intersecting the axis X to the window section 72 of the adjacent first baffle 70a in the axial direction Dx. That is, the first baffle 70a forms an intersecting direction flow path CP configured to flow the tube-exterior fluid Fo in a direction intersecting the axis X, that is, in a direction intersecting the outlet side tube section 33b.
The second baffle 70b is disposed in the first tube chamber 15a and changes the flow direction of the tube-exterior fluid Fo flowing in the first tube chamber 15a. The second baffle 70b is provided along an imaginary plane (not illustrated) extending in the intersecting direction with respect to the axial direction Dx in which the inlet side tube section 33a extends. The second baffle 70b illustrated in the first embodiment is provided along an imaginary plane (not illustrated) extending in a direction perpendicular to the axis X. Additionally, a plurality of second baffles 70b are provided at intervals in the axial direction Dx. The second baffle 70b is formed with a second tube hole 73 through which the inlet side tube section 33a is inserted.
Like the first baffle 70a, the second baffles 70b adjacent to each other in the axial direction Dx have windows 74 at positions shifted from each other when viewed from the axial direction Dx. That is, the tube-exterior fluid Fo flowing in the axial direction Dx through the window section 74 of one second baffle 70b is deflected by a section other than the window section 74 of another second baffle 70b adjacent to the second baffle 70b in the axial direction Dx, and flows in the direction intersecting the axis X to the window section 74 of the another second baffle 70b adjacent to the second baffle 70b in the axial direction Dx. Similar to the first baffle 70a, the second baffle 70b also forms an intersecting direction flow path CP configured to flow the tube-exterior fluid Fo in a direction intersecting the axis X, that is, in a direction intersecting the inlet side tube section 33a. In the first baffle 70a and the second baffle 70b, the number of windows formed per baffle is not limited to one, and for example, two or more windows may be formed. The flow path in which the tube-exterior fluid Fo flows is not limited to the single segmental type illustrated in
As illustrated in
The inlet ends 31 and the outlet ends 32, of the plurality of heat transfer tubes 30 described above, are fixed to the tube plate base material 22. The tube plate base material 22 has strength that can withstand the pressure of the tube-exterior fluid Fo and the tube-interior fluid Fi. As a material for forming the tube plate base material 22, for example, carbon steel can be used. That is, the material of the tube plate base material 22 according to the first embodiment is a metal to which chromium or the like capable of improving corrosion resistance is not intentionally added.
The first backplate 23 is disposed so as to be in contact with the surface of the tube plate base material 22 on the side of the tube-exterior fluid chamber 18. The first backplate 23 is formed in a plate shape thinner than the tube plate base material 22, and covers the surface of the tube plate base material 22 on the side of the tube-exterior fluid chamber 18 from the second end side D2. The first backplate 23 according to the present embodiment is formed in a disk shape, and covers substantially the entire surface 22a of the tube plate base material 22 on the side of the tube-exterior fluid chamber 18. The first backplate 23 is joined to an end section 60c of the second partition wall 60 on the first end side D1 by welding or the like. The first backplate 23 is made of a metal material having a higher corrosion resistance than the tube plate base material 22. As a metal material having high corrosion resistance, for example, a metal having a higher chromium content than the tube plate base material 22, such as stainless steel, can be exemplified. The first backplate 23 may be formed of the same material as the second partition wall 60.
The first backplate 23 includes a screw insertion hole 23a and a plurality of heat transfer tube insertion holes 23b (see
The screw fastener 90 couples the first backplate 23 to the tube plate base material 22 by being screwed on. The screw fastener 90 according to the first embodiment includes a bolt 92 having the above-described screw shaft section 91 and female threads 24 formed in the tube plate base material 22. That is, the first backplate 23 is bolted to the surface facing the second end side D2 of the tube plate base material 22 at a plurality of positions by the screw fasteners 90. Additionally, the screw fastener 90 may have a structure that can be fastened by being screwed on, and in addition to the combination of the bolt 92 and the female threads 24 formed in the tube plate base material 22, a combination of a bis and a bis hole, and a combination of stud bolts that are inserted and secured to the tube plate base material 22 and nuts, or the like, may be used.
The heat exchanger 100 according to the first embodiment has the above-described configuration. Next, the operation of the heat exchanger 100 will be described with reference to
The heat exchanger 100 according to the first embodiment heats the gas turbine fuel, which is a corrosive fluid containing sulfur or the like, as the tube-exterior fluid Fo. In this heat exchanger, the tube-interior fluid Fi flows in from the tube-interior side inlet nozzle 16a, and the tube-exterior fluid Fo flows in from the first nozzle stub 14a.
First, the tube-interior fluid Fi is pressure-fed by a pump or the like and flows from the tube-interior side inlet nozzle 16a into the inlet chamber 17A. The tube-interior fluid Fi flowing into the inlet chamber 17A flows from the inlet end 31 of the heat transfer tube 30 into the tube-interior flow path inside the heat transfer tube 30, and reaches the outlet end 32 via the inlet side tube section 33a, the curved-tube section 34, and the outlet side tube section 33b. The tube-interior fluid Fi reaching the outlet end 32 flows out to the outlet chamber 17B, and then flows out to the outside of the outer cylinder 10 from the tube-interior side outlet nozzle 16b.
On the other hand, the tube-exterior fluid Fo flows from the first nozzle stub 14a into the second tube chamber 15b via the cylinder-interior inlet flow path 25 formed between the inner cylinder 40 and the outer cylinder 10. Here, the space S1 formed between the inner cylinder 40 and the outer cylinder 10 is partitioned by the space partition member 43 in the axial direction Dx. The pressure P1 of the tube-exterior fluid Fo acting on the surface 43b on the first end side D1 of the space partition member 43 is lower than the pressure P2 of the tube-exterior fluid Fo acting on the surface 43a on the second end side D2 (P1<P2). This is because the pressure of the tube-exterior fluid Fo outside the tube on the first end side D1 decreases due to pressure loss occurring in the first tube chamber 15a and the second tube chamber 15b. Since the first seal 44 is provided between the space partition member 43 and the inner peripheral surface 10c of the outer cylinder 10, leakage of the tube-exterior fluid Fo, due to the pressure difference, from the gap between the space partition member 43 and the inner peripheral surface 10c of the outer cylinder 10 is suppressed.
The tube-exterior fluid Fo flowing into the second tube chamber 15b flows from the first end side D1 toward the second end side D2 inside the second tube chamber 15b formed inside the inner cylinder 40. At this time, the tube-exterior fluid Fo flows in the meandering flow path formed by the inner cylinder 40, the second partition wall 60, and the plurality of first baffles 70a. That is, the tube-exterior fluid Fo flows from the first end side D1 to the second end side D2 while meandering in the second tube chamber 15b. In the process of flowing through the second tube chamber 15b, the tube-exterior fluid Fo exchanges heat with the tube-interior fluid Fi flowing through the plurality of outlet side tube sections 33b.
The tube-exterior fluid Fo flowing to the second end side D2 of the second tube chamber 15b flows into the first tube chamber 15a through the opening of the opening forming section 63 formed endmost to the second end side D2 of the small width section 61 of the second partition wall 60. The tube-exterior fluid Fo flowing into the first tube chamber 15a flows in the first tube chamber 15a from the second end side D2 toward the first end side D1. In other words, the direction in which the tube-exterior fluid Fo flows is reversed at the opening forming section 63. Further, in other words, the opening forming section 63 serves as a return section of the flow path through which the tube-exterior fluid Fo flows.
The tube-exterior fluid Fo flowing into the first tube chamber 15a flows through a meandering flow path formed by the inner cylinder 40, the second partition wall 60, and the plurality of second baffles 70b in the same manner as when flowing through the second tube chamber 15b. That is, the tube-exterior fluid Fo flows from the second end side D2 to the first end side D1 while meandering in the first tube chamber 15a. The tube-exterior fluid Fo exchanges heat with the internal tube-interior fluid Fi flowing in the plurality of inlet side tube sections 33a in the process of flowing in the first tube chamber 15a. Additionally, the tube-exterior fluid Fo having exchanged heat with the internal tube-interior fluid Fi in the inlet side tube sections 33a flows from the opening of the inner cylinder 40 into the cylinder-interior outlet flow path 26 between the inner surface of the outer cylinder 10 and the outer surface of the inner cylinder 40. At this time, the tube-exterior fluid Fo comes into contact only with the first backplate 23 of the tube plate 20, and flows into the cylinder-interior outlet flow path 26 without coming into contact with the tube plate base material 22. Here, the tube-exterior fluid Fo flowing into the cylinder-interior outlet flow path 26 is heated to a high temperature, and the tube plate 20 and the outer cylinder 10 on the first tube chamber 15a side are also heated by this high-temperature tube-exterior fluid Fo. The tube-exterior fluid Fo flowing into the cylinder-interior outlet flow path 26 flows out to the outside of the outer cylinder 10 from the second nozzle stub 14b.
According to the heat exchanger 100 of the first embodiment described above, on the surface 22a of the tube plate base material 22 on the first tube chamber 15a side, a first backplate 23 formed of a material having higher corrosion resistance than the tube plate base material 22 is arranged. Therefore, when the tube-exterior fluid Fo flowing in the first tube chamber 15a becomes higher in temperature than the tube-exterior fluid Fo flowing in the second tube chamber 15b, progression of corrosion by the surface 22a of the tube plate base material 22 on the first tube chamber 15a side contacting the tube-exterior fluid Fo having increased corrosiveness can be suppressed. Further, the first backplate 23 is connected to the tube plate base material 22 by a screw fastener 90 and is joined to the end section of the second partition wall 60 on the first end side D1. That is, the first backplate 23 is joined only to the second partition wall 60, not to the outer cylinder 10, and is fixed to the tube plate base material 22 only by a screw fastener 90 in which the screw shaft section 91 is loosely inserted into the screw insertion hole 23a. Therefore, even in a case where a difference in thermal elongation occurs between the tube plate base material 22 and the outer cylinder 10 and the first backplate 23, when the force acting on the first backplate 23 due to this thermal elongation difference exceeds the fixing force by the screw fastener 90, the first backplate 23 can be slightly displaced with respect to the screw fastener 90 to allow the first backplate 23 to escape. Therefore, it is possible to suppress an excessive stress from being applied to the first backplate 23 due to the thermal elongation difference. Therefore, it is possible to suppress an increase in manufacturing cost and progression of corrosion, and to suppress a decrease in durability.
Moreover, the inner cylinder 40 and the space partition member 43 are made of a material having a higher corrosion resistance than the tube plate base material 22. Therefore, even when the external tube-exterior fluid Fo, which is a high-temperature corrosive fluid, flows in the first tube chamber 15a, corrosion of the inner cylinder 40 and the space partition member 43 can be suppressed. Further, the inner cylinder 40 and the second partition wall 60 are joined, and the space partition member 43 is not joined to the outer cylinder 10. Therefore, even when a thermal elongation difference occurs between the outer cylinder 10, the inner cylinder 40, and the space partition member 43, the inner cylinder 40 and the space partition member 43 are displaced relative to the outer cylinder 10, so that stress applied to the space partition member 43 and the inner cylinder 40 can be suppressed.
Further, even when a gap is formed between the space partition member 43 and the outer cylinder 10, the gap is closed by the first seal 44, and therefore, the flow of the tube-exterior fluid Fo through the gap can be prevented. Consequently, a decrease in heat exchange efficiency can be suppressed.
Similarly, even when a gap is formed between the second partition wall 60 and the outer cylinder 10, since the gap between the second partition wall 60 and the outer cylinder 10 is closed by the second seal 64, it is possible to prevent the flow of the tube-exterior fluid Fo between the first tube chamber 15a and the second tube chamber 15b. Therefore, a decrease in heat exchange efficiency can be suppressed.
Next, a heat exchanger according to a second embodiment of the present invention will be described with reference to the drawings. The heat exchanger according to the second embodiment is different from the heat exchanger according to the first embodiment only in that a second backplate 27 is further provided. Therefore, the same components as those in the first embodiment are denoted by the same reference numerals, and redundant description is omitted.
As illustrated in
The plurality of second backplates 27 are formed in, for example, a rectangular shape curved along a curved surface of the inner peripheral surface 10c of the outer cylinder 10B, and are arranged such that the longitudinal direction thereof faces the circumferential direction centered around the axis X. While the outer cylinder 10B is made of a metal such as carbon steel, the second backplate 27, like the first backplate 23, is made of a metal such as stainless steel, which has higher corrosion resistance than the outer cylinder 10B. Further, the second backplate 27 is formed thinner than the outer cylinder 10B. The peripheral edge section 27a of the second backplate 27 is joined to the inner peripheral surface 10c of the outer cylinder 10B by building up welding or the like. The gap between the adjacent second backplates 27 is also filled by building up welding or the like. It should be noted that the second backplate 27 may be formed by adding spot welding to a section inside the peripheral edge section 27a so that a section inside the peripheral edge section 27a does not float from the inner peripheral surface 10c of the outer cylinder 10B.
According to the second embodiment, of the inner peripheral surface 10c of the outer cylinder 10B, the region between the space partition member 43 and the tube plate 20, which is provided with the second nozzle stub 14b, is covered with the second backplate 27. Therefore, when the tube-exterior fluid Fo, which is a high-temperature corrosive fluid, flows out from the second nozzle stub 14b, it is possible to prevent the tube-exterior fluid Fo from coming into contact with the inner peripheral surface 10c of the outer cylinder 10B.
Further, since the inner peripheral surface 10c of the outer cylinder 10B is covered with a plurality of second backplates 27, deformation of the second backplate 27 caused by a thermal elongation difference in the axial direction Dx between the outer cylinder 10B and the second backplate 27, for example, can be suppressed. Further, since the second backplate 27 is formed in a rectangular shape, the workability in attaching the second backplate 27 to the inner peripheral surface 10c can be improved.
Next, modified examples of each of the above-described embodiments will be described. Moreover, the same components as those in each embodiment described above are denoted by the same reference numerals, and redundant descriptions are omitted.
For example, as illustrated in
According to the second modified example, the gap between the screw insertion hole 23a and the screw shaft section 91 is closed by the washer W, so that the intrusion of the tube-exterior fluid Fo into the gap between the tube plate base material 22 and the first backplate 23 can be reduced. As a result, corrosion of the tube plate base material 22 can be prevented.
In the first embodiment described above, a case where the first seal 44 and the second seal 64, which are in the form of sheets bent by elastic deformation, such as a lamiflex seal are respectively used, has been described. However, the sealing structure between the second partition wall 60 and the inner peripheral surface of the outer cylinder 10 is not limited to the above-described sealing structure of the first embodiment.
As illustrated in
Each of the screw insertion hole 46a and 60b formed in the receiving plate 46 and the second partition wall 60 has an inner diameter larger than the diameter of the screw shaft section Bs of the bolt B, and the screw shaft section Bs inserted through the screw insertion hole 46a and 60b can be displaced in a direction intersecting the screw shaft section Bs within the range of the screw insertion hole 46a and 60b when an input is applied exceeding the coupling force of the bolt B and the nut N. In this third modified example, one annular washer W3 is used for one set of bolt B and nut N. Like the above-described washer W2, the inner diameter of the washer W3 is smaller than the inscribed circle of the bolt head and slightly larger than the diameter of the screw shaft section Bs. The outer diameter of the washer W3 is larger than the circumscribed circle of the bolt head. Additionally, as illustrated in
Therefore, according to the third modified example, as in the first embodiment, excessive stress can be prevented from being applied to the second partition wall 60 due to the thermal elongation difference between the outer cylinder 10 and the second partition wall 60 of different materials, while suppressing the outflow of the tube-exterior fluid Fo from the high-pressure side to the low-pressure side.
In the above-described third modified example, a case where one annular washer W is used for one set of bolt B and nut N is exemplified. However, the shape of the washer W is not limited to this shape. For example, as illustrated in
In the above-described embodiments and the respective modified examples, the case where the second partition wall 60 is formed of one flat plate is exemplified. However, the second partition wall is not limited to a single plate.
For example, the second partition wall may have a multiple structure such as a second partition wall according to the fifth modified example illustrated in
As illustrated in
The first plate section 260A is arranged on the first tube chamber 15a side, and the second plate section 260B is arranged on the second tube chamber 15b side. The first plate section 260A and the second plate section 260B are spaced apart from each other by a spacer (not illustrated).
The second partition wall 260 thus formed has a small width section 261 and a large width section 262 as in the above-described embodiment. The edge sections of the small width section 261 are respectively separated apart from the inner peripheral surface 10c of the outer cylinder 10. The edge sections of the large width section 262 are slightly separated respectively from the inner peripheral surface 10c of the outer cylinder 10. A second seal 264 configured to close the gap between the first plate section 260A and the inner peripheral surface of the outer cylinder 10 is attached to the edge section of the large width section 262 of the first plate section 260A, similarly to the second seal 64 of the above-described embodiment.
Although
In the opening forming section (not illustrated; equivalent to the opening forming section 63 of the embodiment) formed on the second end side D2 of the second partition wall 260, a leak preventing spacer (not illustrated) is provided in the gap so as to surround the opening forming section in order to prevent the tube-exterior fluid Fo from leaking from the gap between the first plate section 260A and the second plate section 260B.
The inner cylinder 240 according to the fifth modified example includes a first half section 241 and a second half section 242 each formed in a half-cylinder shape extending in the axial direction Dx. The first half section 241 and the second half section 242 of the fifth modified example are each formed in a semicircular arc shape in cross section perpendicular to the axis X. Both end edges of the first half section 241 in the circumferential direction centered around the axis X are joined to the surface of the first plate section 260A by welding or the like. Similarly, both end edges of the second half section 242 in the circumferential direction centered around the axis X are joined to the surface of the second plate section 260B by welding or the like.
The space partition member 43 has the same configuration as that of the above-described embodiment, and is joined to the first half section 241 of the inner cylinder 240 and the first plate section 260A by welding or the like. The space partition member 43 is not joined to the inner peripheral surface of the outer cylinder 10 by welding or the like, but instead includes a first seal 44 (not illustrated) made of a lamiflex seal or the like configured to close a gap generated between the space partition member 43 and the inner peripheral surface 10c of the outer cylinder 10.
Therefore, according to the fifth modified example, for example, the heat exchanger can be assembled by inserting the first unit in which the first plate section 260A, the first half section 241, and the space partition member 43 are joined, and the second unit in which the second plate section 260B and the second half section 242 are joined, into the outer cylinder 10, respectively. Therefore, the heat exchanger can be easily assembled. Further, according to the fifth modified example, the second partition wall 260 has a multiple structure, whereby the heat insulation performance of the second partition wall 260 can be improved.
The present invention is not limited to the above-described embodiments, and includes the above-described embodiments with various modifications added thereto without departing from the spirit of the present invention. That is, the specific shape, configuration, or the like described in the embodiments are merely examples, and can be changed as appropriate.
Although the present invention has been applied to a heat exchanger in which a heat transfer tube is formed in a U-shape, the heat transfer tube is not limited to a U-shape heat exchanger.
Further, as a fastener having a shaft section, a screw fastener in which an external screw is formed on a screw shaft section is exemplified, but a fastener such as a rivet may be used.
Further, in the first embodiment described above, the case where the tube-exterior fluid Fo is heated has been described, but the heat exchanger according to the present invention is also applicable to the case where the tube-exterior fluid Fo is cooled. In this case, the high-temperature tube-exterior fluid Fo flows into the outer cylinder 10 from the second nozzle stub 14b and flows out from the first nozzle stub 14a to the outside of the outer cylinder 10. Further, tube-interior fluid Fi serving as a refrigerant may flow from the outlet end 32 to the inlet end 31. Also in this case, since the temperature of the tube-exterior fluid Fo just after flowing in from the second nozzle stub 14b is high, it is possible to suppress the progression of corrosion due to the tube-exterior fluid Fo having a high temperature, and to suppress the increase in manufacturing cost and the deterioration of durability due to the stress caused by the thermal elongation difference.
Furthermore, in each of the embodiments described above, the case where the first backplate 23 is formed in a disk shape has been exemplified. However, the first backplate 23 only needs to cover a section of the tube plate base material 22 that faces at least the first tube chamber 15a. That is, the first backplate may be formed in a semicircular disk shape.
Further, in the first embodiment described above, the case where the first backplate 23 is in close contact with the tube plate base material 22 has been described. However, a gap may be formed between the first backplate 23 and the tube plate base material 22.
Further, although the heat exchanger 100 described above is used as a heat exchanger for increasing the temperature of the fuel gas of the gas turbine, it can be used for heat exchange for other than the fuel gas of the gas turbine as long as the corrosive fluid is an external tube-exterior fluid Fo.
The present invention is applicable to a heat exchanger. According to the present invention, it is possible to suppress an increase in manufacturing cost and progression of corrosion, and to suppress a decrease in durability.
| Number | Date | Country | Kind |
|---|---|---|---|
| JP2017-195367 | Oct 2017 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2018/034901 | 9/20/2018 | WO | 00 |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2019/069703 | 4/11/2019 | WO | A |
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| International Search Report dated Nov. 27, 2018 in International Application No. PCT/JP2018/034901. |
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| Number | Date | Country | |
|---|---|---|---|
| 20200166280 A1 | May 2020 | US |
