Heat exchanger

Abstract

A heat exchanger (1) includes: an inner tube (2) through which a heat medium (92) flows; an outer tube (3) into which the inner tube (2) is inserted and which has an inner circumferential surface (3a) facing the outer circumferential surface (2a) of the inner tube (2) across a gap, such that steam (91) flows through the area between the outer circumferential surface (2a) and the inner circumferential surface (3a); and a channel wall section (4) running from the outer circumferential surface (2a) to the inner circumferential surface (3a). The channel wall section (4) proceeds along the direction in which the inner tube (2) or the outer tube (3) extends while circling back and forth between the outer circumferential surface (2a) and the inner circumferential surface (3a).

Description

heat exchanger

[0001] The present disclosure relates to a heat exchanger.

[0002] A so-called shell-and-tube heat exchanger is known. The internal space of the shell and the internal space of the tube are separated from each other. Heat is exchanged between the medium flowing through the tube and the medium flowing through the shell through the wall of the tube. For example, a heat exchanger disclosed in Patent Document 1 includes a central core (30) and a strand (70) wound helically around the central core (30).

[0003] EP 3760958

[0004] A heat exchanger includes a pipe through which a heat-receiving medium flows and a pipe through which a heat-transferring medium flows. For example, steam can be used as a heat-transferring medium. When steam comes into contact with a pipe through which a heat-receiving medium flows, the heat contained in the steam is transferred to the heat-receiving medium via the wall of the pipe. As a result, a liquid film may form on the surface of the pipe through which the heat-receiving medium flows. The surface of the pipe through which the heat-receiving medium flows is a path for heat transfer. If a liquid film exists on this path for heat transfer, the liquid film acts as a thermal resistance, making it difficult for heat to transfer. As a result, there is a risk that the efficiency of the heat exchanger may decrease.

[0005] The present disclosure describes a heat exchanger that can suppress a decrease in the efficiency of heat exchange.

[0006] A heat exchanger according to the present disclosure includes at least one heat exchange unit capable of transferring heat between a first heat medium and a second heat medium. The heat exchange unit includes a first tube through which the first heat medium flows, a second tube through which the first tube is inserted and which includes a second inner circumferential surface facing a first outer circumferential surface of the first tube via a gap, and through which the second heat medium flows in a region between the first outer circumferential surface and the second inner circumferential surface, and a flow path wall extending from the first outer circumferential surface to the second inner circumferential surface. The flow path wall travels along the extension direction of the first tube or the second tube while circulating between the first outer circumferential surface and the second inner circumferential surface.

[0007] In this heat exchanger, a flow path wall is disposed between the first tube and the second tube. The flow path wall travels between the first outer circumferential surface and the second inner circumferential surface along the extension direction of the first tube or the second tube. As a result, a flow path is formed that travels around the first tube. When a heat medium is introduced into this flow path, heat exchange occurs between the heat medium and the heat medium passing through the first tube, producing condensate. The condensate then flows around the first tube in accordance with the flow of the heat medium that flows around the first tube. As a result, centrifugal force acts on the condensate, causing it to quickly move away from the outer circumferential surface of the first tube, which functions as a heat exchange surface. Therefore, condensate does not accumulate on the outer circumferential surface of the first tube, allowing the outer circumferential surface of the first tube to continue to function as a heat exchange surface. As a result, a decrease in the efficiency of the heat exchanger can be suppressed.

[0008] In the heat exchanger, the flow path wall may be inclined with respect to a radial direction of the first tube. With this configuration, the condensed liquid can flow in the direction of the inclination of the flow path wall.

[0009] In the heat exchanger, the flow path through which the second heat medium flows, which is surrounded by the first outer circumferential surface, the second inner circumferential surface, and the flow path wall, may be a spiral path that circles around the first tube. With this configuration, the condensed liquid can flow along the spiral flow path without stagnation.

[0010] In the heat exchanger described above, the flow path wall portion may be integral with the first tube and the second tube. With this configuration, the heat exchanger can be manufactured by three-dimensional modeling technology.

[0011] The heat exchanger may further include a first inlet for introducing the first heat medium into the first tube and a second inlet for introducing the second heat medium into the second tube, thereby achieving a simple heat exchanger.

[0012] The heat exchanger may further include a first inlet for introducing the first heat medium into the plurality of first tubes and a second inlet for introducing the second heat medium into the plurality of second tubes. With this configuration, the amount of heat exchangeable medium can be increased.

[0013] The heat exchanger of the present disclosure can suppress a decrease in heat exchange efficiency.

[0014] Fig. 1 is a perspective view showing the appearance of a heat exchanger according to a first embodiment. Fig. 2 is a perspective view showing the internal structure of the heat exchanger shown in Fig. 1. Fig. 3 is a cross-sectional view showing the internal structure of the heat exchanger shown in Fig. 1. Fig. 4 is a perspective view showing the appearance of a heat exchanger according to a second embodiment. Fig. 5 is a cross-sectional perspective view showing the main internal structure of the heat exchanger shown in Fig. 4.

[0015] Hereinafter, the heat exchanger of the present disclosure will be described in detail with reference to the drawings. In each drawing, the same or corresponding parts are designated by the same reference numerals, and duplicated explanations will be omitted.

[0016] First Embodiment As shown in FIG. 1 , the heat exchanger 1 receives steam 91 (second heat medium). Furthermore, the heat exchanger 1 receives a heat medium 92 (first heat medium). Examples of the heat medium 92 include an organic solvent and acetone. The heat exchanger 1 removes heat from the received steam 91. As a result, some or all of the water contained in the steam 91 condenses. The condensed water is referred to as "condensate" in the following description. The heat exchanger 1 discharges condensate 93 as a result of the heat exchange.

[0017] The heat exchanger 1 has a steam inlet 11 (second inlet), a condensate outlet 12, a first heat medium port 13, and a second heat medium port 14 (first inlet). The steam inlet 11 is connected to, for example, a boiler. The steam inlet 11 receives steam 91 provided from the boiler. The steam inlet 11 is connected to a condensate outlet 12. The condensate outlet 12 discharges condensate 93. The condensate outlet 12 is connected to, for example, a flash tank. The condensate outlet 12 provides condensate 93 to the flash tank. The first heat medium port 13 is connected to, for example, a raw material tank. The first heat medium port 13 receives a heat medium 92 provided from the raw material tank before heat exchange. The first heat medium port 13 is connected to a second heat medium port 14. The second heat medium port 14 discharges the heat medium 92 after heat exchange. The second heat medium port 14 is connected to, for example, a reactor. The second heat medium port 14 supplies the heat medium 92 after heat exchange to the reactor.

[0018] As an example, as shown in FIG. 1 , the heat exchanger 1 is arranged so that its axis L is parallel to the vertical direction. This arrangement can be referred to as "arranging the heat exchanger 1 vertically." In this arrangement, the steam inlet 11 is positioned vertically above the condensate outlet 12. Therefore, the steam 91 and condensate 93 move from top to bottom due to gravity. More specifically, the steam 91 and condensate 93 move from top to bottom while swirling along a spiral flow path SF (described below). In contrast, the first heat medium port 13 is positioned vertically below the second heat medium port 14. Therefore, the heat medium 92 moves from bottom to top against gravity. In other words, the direction of movement of the steam 91 and condensate 93 along the axis L is opposite to the direction of movement of the heat medium 92. This type of flow is called "countercurrent" or "complete countercurrent."

[0019] The direction of movement of the steam 91 and the direction of movement of the heat medium 92 may be the same. That is, in the above description, the heat medium 92 may be introduced from the portion referred to as the second heat medium port 14 and discharged from the portion referred to as the first heat medium port 13. This type of flow is called "parallel flow." The direction of flow of the heat medium 92 does not make any essential difference to the structure of the heat exchanger 1. That is, the heat exchanger 1 of this embodiment can be used as either a counterflow type or a parallel flow type.

[0020] 2, the heat exchanger 1 has an inner tube 2 (first tube) and an outer tube 3 (second tube). The inner tube 2 and the outer tube 3 have a substantially cylindrical shape. The heat exchanger 1 is a so-called single-tube type having one inner tube 2 and one outer tube 3.

[0021] The outer diameter of the inner tube 2 is smaller than the inner diameter of the outer tube 3. The inner tube 2 is inserted into the outer tube 3 so as to be substantially coaxial with the outer tube 3. The first and second ends of the inner tube 2 protrude from the outer tube 3. That is, the length from the first end to the second end of the inner tube 2 is longer than the length of the outer tube 3. The first end of the inner tube 2 is the first heat medium port 13 described above. The second end of the inner tube 2 is the second heat medium port 14 described above. Therefore, the inner tube 2 forms a flow path for the heat medium 92. The inner circumferential surface 2b (second inner circumferential surface) of the inner tube 2 may be a smooth surface without protrusions. Alternatively, the inner circumferential surface 2b of the inner tube 2 may have multiple protrusions formed thereon. The protrusions have the effect of disrupting the flow of the heat medium 92 and increasing the heat transfer area of ​​the inner circumferential surface 2b. As a result, this contributes to improving heat exchange efficiency.

[0022] The outer tube 3 covers a portion of the inner tube 2. A first end of the outer tube 3 is closed by a first cover wall 31. The first cover wall 31 extends from the first end of the outer tube 3 to the outer peripheral surface 2a (first outer peripheral surface) of the inner tube 2. A steam inlet pipe section 32 is connected to the first cover wall 31. The steam inlet pipe section 32 is a tubular portion including the steam inlet 11 described above. The steam inlet pipe section 32 includes a parallel pipe section 321 extending parallel to the axis L of the inner tube 2 and a connecting pipe section 322 extending in a direction inclined with respect to the axis L. The parallel pipe section 321 includes the steam inlet 11 described above. The connecting pipe section 322 extends from the parallel pipe section 321 to the first cover wall 31. Steam 91 is received through the steam inlet 11 of the parallel pipe section 321, passes through the parallel pipe section 321, and reaches the connecting pipe section 322. The steam 91 then flows from the connecting pipe portion 322 through the opening of the first cover wall 31 to the outer tube 3 .

[0023] The opposite end of the outer tube 3 has a similar configuration. That is, the second end of the outer tube 3 is closed by a second cover wall 33, and a condensate discharge pipe 34 is connected to the second cover wall 33. The condensate discharge pipe 34 is a tubular portion including the condensate outlet 12 described above. The condensate discharge pipe 34 also includes a second parallel pipe portion 341 extending parallel to the axis L of the inner tube 2 and a second connecting pipe portion 342 extending in a direction inclined relative to the axis L. The second parallel pipe portion 341 includes the condensate outlet 12 described above. The second connecting pipe portion 342 extends from the first parallel pipe portion 321 to the first cover wall 31. The condensate 93 reaches the second connecting pipe portion 342 from the opening of the second cover wall 33. The condensate 93 reaches the second parallel pipe portion 341 via the second connecting pipe portion 342. The condensate 93 is then discharged from the condensate outlet 12 of the second parallel pipe portion 341 .

[0024] The inner circumferential surface 3 a of the outer tube 3 is spaced from the outer circumferential surface 2 a of the inner tube 2. In other words, a gap is formed between the inner circumferential surface 3 a of the outer tube 3 and the outer circumferential surface 2 a of the inner tube 2. Steam 91 received from the steam inlet pipe 32 passes through the gap between the inner circumferential surface 3 a of the outer tube 3 and the outer circumferential surface 2 a of the inner tube 2 and reaches the condensate discharge pipe 34. Heat is lost from the steam 91 as it moves through the gap. As a result, part or all of the steam 91 becomes condensed liquid as it moves through the gap.

[0025] A continuous flow path wall 4 is provided in the gap. The flow path wall 4 divides the gap along the direction of the axis L. That is, the inner peripheral side of the flow path wall 4 is connected to the outer peripheral surface 2 a of the inner tube 2. The outer peripheral side of the flow path wall 4 is connected to the inner peripheral surface 3 a of the outer tube 3. As will be described later, since the heat exchanger 1 is integrally molded, there is no clear boundary line between the inner peripheral side of the flow path wall 4 and the outer peripheral surface 2 a of the inner tube 2. Similarly, there is no clear boundary line between the outer peripheral side of the flow path wall 4 and the inner peripheral surface 3 a of the outer tube 3.

[0026] 3, the flow path wall 4 includes a flow path main surface 4a and a flow path back surface 4b. As described above, when the heat exchanger 1 is disposed vertically, the flow path main surface 4a is a surface defined by a normal line including a vertically upward component. The flow path back surface 4b is a surface defined by a normal line including a vertically downward component.

[0027] The flow path wall 4 forms a flow path from the opening of the first cover wall 31 to the opening of the second cover wall 33. The flow path is configured to spiral around the inner tube 2. More specifically, the flow path wall 4 travels along the axis L of the inner tube 2 while circling between the outer peripheral surface 2 a of the inner tube 2 and the inner peripheral surface 3 a of the outer tube 3. The distance from the flow path main surface 4 a to the flow path back surface 4 b in the direction along the axis L when the flow path wall 4 rotates once around the axis L can be defined as the pitch of the flow path wall 4. The pitch of the flow path wall 4 may be approximately constant. In the following description, this flow path is referred to as a "spiral flow path." The "spiral" in this embodiment may be interpreted as a strict "spiral" defined geometrically. Furthermore, the "spiral" in this embodiment may be interpreted as simply circling around the inner tube 2.

[0028] The spiral flow path SF travels along the axis L of the inner tube 2 while circling between the outer peripheral surface 2a of the inner tube 2 and the inner peripheral surface 3a of the outer tube 3. The cross-sectional shape of the spiral flow path SF is, for example, a parallelogram. The parallelogram cross sections of the spiral flow path SF are arranged at equal intervals along the direction of the axis L. The spiral flow path SF is an area surrounded by the outer peripheral surface 2a of the inner tube 2, the inner peripheral surface 3a of the outer tube 3, the main flow path surface 4a of the flow path wall 4, and the back flow path surface 4b of the flow path wall 4. The outer peripheral surface 2a of the inner tube 2 is parallel to the inner peripheral surface 3a of the outer tube 3. Similarly, the main flow path surface 4a of the flow path wall 4 is parallel to the back flow path surface 4b of the flow path wall 4.

[0029] As an example, the flow path wall 4 is inclined with respect to the outer peripheral surface 2a of the inner tube 2. This "inclined" refers to the fact that the inner angle A1 formed between the main flow path surface 4a of the flow path wall 4 and the outer peripheral surface 2a of the inner tube 2 is not a right angle. For example, the inner angle A1 is an obtuse angle greater than 90 degrees. Similarly, this refers to the fact that the outer angle A2 formed between the main flow path surface 4a of the flow path wall 4 and the inner peripheral surface 3a of the outer tube 3 is not a right angle. For example, the outer angle A2 is an acute angle less than 90 degrees. If the heat exchanger 1 is disposed vertically, the flow path wall 4 can also be said to extend vertically downward. In this case, the inner peripheral surface 3a of the outer tube 3, which forms a certain cross section of the spiral flow path SF, is located below the outer peripheral surface 2a of the inner tube 2, which forms the same cross section. For example, the portion 34c where the inner surface 3a of the outer tube 3 and the main flow path surface 4a of the flow path wall portion 4 are connected is located vertically lower than the portion 24c where the outer surface 2a of the inner tube 2 and the main flow path surface 4a of the flow path wall portion 4 are connected.

[0030] As described above, when the heat exchanger 1 is arranged vertically, the flow path wall portion 4 extends diagonally vertically downward from the outer surface 2 a of the inner tube 2 toward the inner surface 3 a of the outer tube 3.

[0031] As described above, the heat exchanger 1 is composed of components such as the inner tube 2, the outer tube 3, and the flow path wall portion 4. The heat exchanger 1 is formed by integrally molding these multiple components. There are no explicit boundaries, such as joint surfaces, between the components. In other words, the heat exchanger 1 is not obtained by manufacturing the inner tube 2 and the outer tube 3 as separate components and then assembling them together. Such a heat exchanger 1 can be manufactured using so-called three-dimensional modeling technology.

[0032] For example, assume that the heat exchanger 1 is manufactured by stacking materials in the direction of the axis L. In this manufacturing process, the cross sections of the inner tube 2 and the outer tube 3 are perpendicular to the axis L, and therefore additive manufacturing is possible without any problems. However, with three-dimensional manufacturing technology, it is difficult to manufacture a part that extends in a direction perpendicular to the stacking direction (the direction of the axis L in this example). For example, it is difficult to manufacture a part such as a fin in a direction perpendicular to the outer peripheral surface 2 a of the inner tube 2 (a direction perpendicular to the axis L). Such a part is called an "overhang" in the field of three-dimensional manufacturing technology. On the other hand, the flow path wall 4 of the heat exchanger 1 does not extend in a direction perpendicular to the axis L, but rather in a direction inclined by a predetermined angle relative to the axis L. Therefore, the flow path wall 4 does not need to be treated as a so-called overhang, and additive manufacturing is possible without any problems, just like the inner tube 2 and the outer tube 3.

[0033] <Points to Note When Designing a Heat Exchanger> Points to note when designing a heat exchanger will be described before describing the effects of the heat exchanger 1. First, points to note when designing a so-called full condensation type heat exchanger will be described, and then points to note when designing a so-called partial condensation type heat exchanger will be described.

[0034] Assume that a full-condensing heat exchanger is installed horizontally and condensation occurs outside the tubes. In this case, the baffle cut is vertical to prevent condensate from accumulating inside the shell. If the baffle cut is horizontal, the baffle may act as a weir, causing condensate to accumulate. The area where condensate accumulates does not function as a condensation surface (heat exchange surface). Furthermore, the flow of the medium may become unstable. Note that the above considerations are not required when the full-condensing heat exchanger is installed horizontally and condensation occurs inside the tubes. Furthermore, the above considerations are not required when the full-condensing heat exchanger is installed vertically and condensation occurs outside the tubes. On the other hand, when a full-condensing heat exchanger is installed vertically and condensation occurs inside the tubes, the inner diameter of the tubes must be appropriately set to avoid the effects of condensate film growth on the lower part of the tubes. Ideally, the medium flow rate is set to prevent condensate film growth on the inner surface of the tubes. However, since the volume of the medium decreases due to condensation, it is difficult to set a uniform flow rate throughout the tube, and therefore design strategies that suppress the growth of the condensate film (thinning the film) are not often adopted.

[0035] Next, consider a case where a partial condensing heat exchanger is installed horizontally or vertically and condenses outside the tubes. In this case, non-condensable gas may accumulate inside the shell. Therefore, measures must be taken to prevent non-condensable gas from accumulating. For example, a mechanism for discharging accumulated non-condensable gas may be provided. Furthermore, in the case of a downflow, the upward flow of non-condensable gas increases the possibility of non-condensable gas accumulating.

[0036] Even heat exchangers designed with these considerations in mind have had the following problems. First, shell-and-tube heat exchangers do not have a mechanism for actively removing the condensed liquid film. As a result, a liquid film forms on the condensation surface, reducing the effective heat transfer surface area that contributes to heat exchange. Second, adopting a design that overcomes this problem places restrictions on the conditions for the heat transfer medium to flow, making highly efficient operation in complete counterflow difficult. Third, when condensation occurs in the shell-side space, non-condensable gases accumulate. This accumulation of non-condensable gases can also reduce the efficiency of heat exchange.

[0037] <Operational Effects of Heat Exchanger> The heat exchanger 1 of the present disclosure solves the above-described problems by providing the following operational effects.

[0038] A heat transfer medium 92 flows from bottom to top in the inner tube 2. Steam 91 is introduced from the steam inlet 11. The steam 91 has a predetermined kinetic energy that can be defined by pressure and flow velocity. This steam 91 moves to the spiral flow path SF. The outer peripheral surface 2a of the inner tube 2, which defines the spiral flow path SF, functions as a heat exchange surface in the spiral flow path SF. Furthermore, the flow path main surface 4a of the flow path wall 4 extends from the inner peripheral surface 3a and can be considered to be a region affected by the heat transfer medium 92. Therefore, the flow path main surface 4a of the flow path wall 4 also functions as a heat exchange surface.

[0039] The steam 91 in contact with the outer peripheral surface 2a and / or the flow path main surface 4a loses heat and reaches its saturation limit, condensing. The steam 91 near the outer peripheral surface 2a and / or the flow path main surface 4a also loses heat and reaches its saturation limit, condensing. As a result of condensation, water is produced. Because the inner tube 2 is oriented such that its axis L is vertical, its outer peripheral surface 2a also extends vertically downward. Therefore, the condensed liquid 93 condensed on the outer peripheral surface 2a moves vertically downward due to the action of gravity. The condensed liquid 93 then moves from the outer peripheral surface 2a to the flow path main surface 4a of the flow path wall portion 4, which is connected to the outer peripheral surface 2a. The flow path main surface 4a is also tilted vertically downward. Therefore, the condensed liquid 93 continues to move downward along the flow path main surface 4a. Finally, the condensed liquid 93 reaches the portion 34c where the flow path main surface 4a and the inner circumferential surface 3a of the outer tube 3 are connected.

[0040] Furthermore, when the heat exchanger 1 is disposed vertically, the flow path wall 4 is disposed so as to extend obliquely downward, as shown in FIG. 3 and other figures. When the heat exchanger 1 is disposed in the opposite orientation to that shown in FIG. 3 , the portion 24c where the flow path main surface 4a is connected to the outer peripheral surface 2a of the inner tube 2 is located below the portion 34c where the flow path main surface 4a is connected to the inner peripheral surface 3a of the outer tube 3. As a result, the condensate 93 accumulates in the area surrounded by the outer peripheral surface 2a of the inner tube 2 and the flow path main surface 4a of the flow path wall 4. In other words, the condensate 93 comes into contact with the outer peripheral surface 2a of the inner tube 2, which functions as the main heat exchange surface. Therefore, when the heat exchanger 1 is disposed vertically, it is preferable to dispose it as shown in FIG. 3 and other figures.

[0041] That is, the condensed liquid 93 generated by condensation moves quickly from the outer peripheral surface 2a of the inner tube 2, which is the main heat exchange surface. Furthermore, on the main flow path surface 4a, which is also the heat exchange surface, the condensed liquid 93 moves from the portion close to the outer peripheral surface 2a, which functions well as a heat exchange surface, to the portion farther away. Therefore, the condensed liquid 93 generated by condensation is less likely to remain in the portion functioning as a heat exchange surface. As a result, the condensed liquid 93 does not hinder heat transfer, and a decrease in the efficiency of the heat exchanger 1 can be suppressed.

[0042] In the above explanation, it is assumed that gravity is the driving force for the movement of the condensate 93. However, the movement of the condensate 93 can also be explained by a driving force other than gravity. As already mentioned, steam 91 is received into the heat exchanger 1 at a predetermined flow rate. The steam 91 at a predetermined flow rate flows in a swirling manner along the spiral flow path SF. The condensate 93 is also drawn by the flow of the steam 91 and flows in a swirling manner along the spiral flow path SF. A centrifugal force corresponding to the swirling speed acts on the swirling flowing condensate 93. Since the magnitude of this centrifugal force is proportional to the mass of the object acting on it, the condensate 93 is subjected to a force from the outer peripheral surface 2 a of the inner tube 2 toward the inner peripheral surface 3 a of the outer tube 3. As a result, the condensate 93 quickly moves from the outer peripheral surface 2 a of the inner tube 2, which is the heat exchange surface.

[0043] As shown in Figure 3, the amount of condensed liquid 93 increases toward the downstream side of the spiral flow path SF, and the level of condensed liquid 93 accumulated between the flow path main surface 4a of the flow path wall 4 and the inner circumferential surface 3a of the outer tube 3 rises. The area in contact with the condensed liquid 93 does not function as a heat exchange surface for condensation. As a result, the area of ​​the flow path main surface 4a of the flow path wall 4 that functions as a heat exchange surface upstream gradually increases toward the downstream side. In other words, the area of ​​the flow path main surface 4a of the flow path wall 4 that functions as a heat exchange surface decreases toward the downstream side. However, even in this case, the outer circumferential surface 2a of the inner tube 2 continues to function as a heat exchange surface.

[0044] Furthermore, the condensate 93 accumulated between the flow path main surface 4 a of the flow path wall portion 4 and the inner circumferential surface 3 a of the outer tube 3 flows downstream due to gravity and the high-speed flow of steam 91. In other words, the condensed condensate 93 does not accumulate inside the heat exchanger 1. The condensed condensate 93 is quickly discharged from the condensate outlet 12.

[0045] The heat exchanger 1 of the first embodiment transfers heat from steam 91 to a heat medium 92. The heat exchanger 1 includes an inner tube 2 through which the heat medium 92 flows, an outer tube 3 through which the inner tube 2 is inserted and which includes an inner circumferential surface 3a facing the outer circumferential surface 2a of the inner tube 2 via a gap, and through which steam 91 flows in a region between the outer circumferential surface 2a and the inner circumferential surface 3a, and a flow path wall 4 extending from the outer circumferential surface 2a to the inner circumferential surface 3a. The flow path wall 4 travels along the extension direction of the inner tube 2 or the outer tube 3, circulating between the outer circumferential surface 2a and the inner circumferential surface 3a.

[0046] In short, the heat exchanger 1 of the first embodiment utilizes centrifugal force and gravity to remove liquid films formed on the outer peripheral surface 2 a of the inner tube 2 and the main flow path surfaces 4 a of the flow path walls 4, which are heat exchange surfaces. Furthermore, the heat exchanger 1 of the first embodiment has a so-called free-drain configuration that prevents liquid pools from forming. Furthermore, the flow path walls 4, which are spiral partitions forming the spiral flow paths SF, function as heat exchange sections (fins), ensuring a heat transfer surface that contributes to heat exchange. Furthermore, the heat exchanger 1 of the first embodiment can perform complete counterflow operation. Furthermore, the heat exchanger 1 of the first embodiment allows the steam 91 and condensate 93 to flow through the relatively narrow spiral flow paths SF, thereby suppressing the accumulation of non-compressible gas.

[0047] In this heat exchanger 1, a flow path wall 4 is disposed between the inner tube 2 and the outer tube 3. The flow path wall 4 moves along the extension direction of the inner tube 2 or the outer tube 3 while circling between the outer peripheral surface 2a and the inner peripheral surface 3a. As a result, a spiral flow path SF is formed, which moves around the inner tube 2. When steam 91 is introduced into this spiral flow path SF, heat exchange occurs between the steam 91 and a heat transfer medium 92 passing through the inner tube 2, producing condensate 93. The condensate 93 also flows around the inner tube 2 in accordance with the flow of the steam 91 circulating around the inner tube 2. As a result, centrifugal force acts on the condensate 93, causing it to quickly move from the outer peripheral surface 2a of the inner tube 2, which functions as a heat exchange surface. Therefore, the condensate 93 does not accumulate on the outer peripheral surface 2a of the inner tube 2, allowing the outer peripheral surface 2a of the inner tube 2 to continue to function as a heat exchange surface. As a result, a decrease in the efficiency of the heat exchanger 1 can be suppressed.

[0048] The flow path wall portion 4 is inclined with respect to the radial direction of the inner tube 2. With this configuration, the condensate 93 can flow in the direction in which the flow path wall portion 4 is inclined.

[0049] The spiral flow path SF, through which the steam 91 flows and which is surrounded by the outer circumferential surface 2 a, the inner circumferential surface 3 a, and the flow path wall, has a spiral shape that circles around the inner tube 2. With this configuration, the condensed liquid 93 can flow along the spiral flow path SF without being retained.

[0050] The flow path wall portion 4 is integral with the inner tube 2 and the outer tube 3. According to this configuration, the heat exchanger 1 can be manufactured by three-dimensional modeling technology.

[0051] The heat exchanger 1 further includes a first heat medium port 13 for introducing the heat medium 92 into one of the inner tubes 2, and a steam inlet 11 for introducing the steam 91 into one of the outer tubes 3. This configuration allows the heat exchanger 1 to have a simple configuration.

[0052] Second Embodiment A heat exchanger 1A shown in Fig. 4 is formed by bundling seven of the above-described heat exchangers 1. With such a configuration, the ability to condense the steam 91 can be improved.

[0053] The heat exchanger 1A has a plurality of heat exchange sections 10A to 10G, a first branched lid section 5, and a second branched lid section 6. Like the heat exchanger 1 of the first embodiment, the heat exchanger 1A of the second embodiment can also be obtained as an integrated structure using three-dimensional modeling technology.

[0054] As shown in Figure 4, the heat exchanger 1A has seven heat exchange sections 10A to 10G. Six heat exchange sections 10B to 10G are arranged side by side around one heat exchange section 10A at an angle of 60 degrees. The individual heat exchange sections 10A to 10G have the same configuration. Each of the heat exchange sections 10A to 10G has an inner tube 2, an outer tube 3, and a flow path wall section 4. The specific configuration of these components is the same as the inner tube 2, outer tube 3, and flow path wall section 4 provided in the heat exchanger 1 of the first embodiment.

[0055] The first branched lid section 5 is disposed on the first end side of the seven heat exchange sections 10A to 10G. The first branched lid section 5 has a first heat medium inlet / outlet section 51 and a steam inlet section 52.

[0056] As shown in FIG. 5 , the first heat medium inlet / outlet section 51 is connected to the inner tubes 2 of the multiple heat exchange units 10A to 10G. That is, the first heat medium inlet / outlet section 51 can receive the heat medium 92 from the multiple inner tubes 2 and can guide the heat medium 92 to the multiple inner tubes 2. The first heat medium inlet / outlet section 51 has one first inlet pipe section 511 and multiple (seven) first branch pipe sections 512A to 512G. The outer end of the first inlet pipe section 511 is an opening for discharging or receiving the heat medium 92. Seven first branch pipe sections 512A to 512G are connected to the inner end of the first inlet pipe section 511. Each of the first branch pipe sections 512A to 512G is connected to a respective one of the inner tubes 2 of the seven heat exchange units 10A to 10G.

[0057] The steam introduction section 52 guides steam 91 received from the steam inlet 11 to the spiral flow paths SF of the seven heat exchange sections 10A to 10G. The steam introduction section 52 is a cylindrical section formed to surround the portion of the first heat medium inlet / outlet section 51 where the first introduction pipe section 511 and the first branch pipe sections 512A to 512G are connected. The steam introduction section 52 includes a lid section 521 corresponding to the first lid wall 31 in the heat exchanger 1 of the first embodiment and a cylindrical section 522 surrounding the seven first branch pipe sections 512A to 512G. The space formed by the lid section 521 and the cylindrical section 522 is connected to each of the seven spiral flow paths SF. On the other hand, the space formed by the lid section 521 and the cylindrical section 522 is not connected to the space formed by the first heat medium inlet / outlet section 51.

[0058] A second branched lid part 6 is disposed on the second end side of the seven heat exchange parts 10A to 10G. The configuration of the second branched lid part 6 is the same as that of the first branched lid part 5, so a detailed description will be omitted.

[0059] <Effects> The heat exchanger 1A of the second embodiment can also suppress a decrease in heat exchange efficiency, similar to the heat exchanger 1 of the first embodiment. That is, the heat exchanger 1A of the second embodiment further includes a first inlet for introducing a heat medium into the plurality of inner tubes 2 and a second inlet for introducing a second heat medium into the plurality of outer tubes 3. This configuration can increase the amount of steam 91 that can be heat exchanged.

[0060] The heat exchanger of the present disclosure is not limited to the embodiments described below, and various modifications are possible without departing from the spirit and scope of the present invention. For example, the heat exchanger of the present disclosure may have the following configurations.

[0061] The present disclosure is [1] "a heat exchanger characterized by having a spiral flow path through which a heat-exchanging fluid flows around the tubes of the heat exchanger."

[0062] The present disclosure is [2] "A heat exchanger according to the above [1], in which a portion of the flow path of the fluid flowing around the tube is integrally installed on the outer surface of the tube."

[0063] The present disclosure is [3] "A heat exchanger according to the above [1] or [2], wherein a portion of the outer diameter of the tube forms a part of a flow path for a fluid flowing around the tube."

[0064] The present disclosure is [4] "A heat exchanger described in any one of the above [1] to [3], wherein the tube and the flow path around the tube have a double-pipe structure, and a flow path for the fluid flowing around the tube is formed on the outer side of the internal flow path of the double pipe."

[0065] The present disclosure is [5] "A heat exchanger described in any one of [1] to [4] above, wherein the spiral flow path is inclined so as to become lower toward the outside in the tube radial direction."

[0066] The present disclosure is [6] "A heat exchanger according to any one of the above [1] to [5], wherein the heat exchanger includes a plurality of tubes."

[0067] The present disclosure is [6] "A heat exchanger described in any one of [1] to [6] above, wherein the heat exchanger is manufactured using a 3D printer."

[0068] DESCRIPTION OF SYMBOLS 1, 1A...heat exchanger, 2...inner tube, 2a...outer peripheral surface (first outer peripheral surface), 3...outer tube, 3a...inner peripheral surface (second inner peripheral surface), 31...first cover wall, 32...steam inlet pipe section, 33...second cover wall, 34...condensate discharge pipe section, 321...parallel pipe section, 322...connecting pipe section, 341...parallel pipe section, 342...connecting pipe section, 4...flow path wall section, 4a...flow path main surface, 4b...flow path back surface, 5...first branch cover section, 51...first heat medium inlet outlet portion, 52...steam introduction portion, 511...first introduction pipe portion, 512A to 512G...first branch pipe portion, 521...lid portion, 522...tubular portion, 6...second branch lid portion, 10A...heat exchange portion, 10A to 10G...heat exchange portion, 11...steam inlet, 12...condensate outlet, 13...first heat medium port, 14...second heat medium port, 91...steam, 92...heat medium, 93...condensate, A1...inner angle, A2...outer angle, L...axis, SF...spiral flow path.

Claims

1. a first heat exchange unit and a second heat exchange unit capable of transferring heat between the first heat medium and the second heat medium; a first branched lid that is integral with the first heat exchange unit and the second heat exchange unit on the side of first ends of the first heat exchange unit and the second heat exchange unit; a second branched lid that is integral with the first heat exchange unit and the second heat exchange unit on the second end side of the first heat exchange unit and the second heat exchange unit, Each of the first heat exchange unit and the second heat exchange unit is a first tube through which the first heat medium flows; a second tube into which the first tube is inserted, the second tube including a second inner circumferential surface facing the first outer circumferential surface of the first tube with a gap therebetween, the second heat medium flowing through a region between the first outer circumferential surface and the second inner circumferential surface; a flow path wall portion extending from the first outer peripheral surface to the second inner peripheral surface, the flow path wall portion travels along the extending direction of the first tube or the second tube while circulating between the first outer peripheral surface and the second inner peripheral surface, The flow path wall portion is integral with the first tube and the second tube.

2. The heat exchanger according to claim 1 , wherein the flow path wall portion is inclined with respect to a radial direction of the first tube.

3. The heat exchanger according to claim 1 , wherein the flow path through which the second heat medium flows and which is surrounded by the first outer peripheral surface, the second inner peripheral surface, and the flow path wall portion has a spiral shape that circles around the first tube.

4. (delete)

5. (delete)

6. The first branch lid is a first inlet that is integral with each of the first tubes of the first heat exchange unit and the second heat exchange unit and that introduces the first heat medium into each of the first tubes of the first heat exchange unit and the second heat exchange unit; A heat exchanger as described in any one of claims 1 to 3, including a second inlet that is integral with each of the second tubes of the first heat exchange section and the second tubes of the second heat exchange section and that guides the second heat medium to each of the second tubes of the first heat exchange section and the second tubes of the second heat exchange section.

7. 2. The heat exchanger according to claim 1, wherein the flow path through which the second heat medium flows, surrounded by the first outer peripheral surface, the second inner peripheral surface, and the flow path wall portion, is spirally circumferential around the first tube, and the cross-sectional shape including the axis of the first tube is a parallelogram.

8. a flow path through which the second heat medium flows, the flow path being surrounded by the first outer peripheral surface, the second inner peripheral surface, and the flow path wall portion, has a spiral shape that circulates around the first tube, and a cross section including an axis of the first tube has a shape of a parallelogram, The heat exchanger according to claim 1 , wherein the parallelogram cross sections of the flow paths are arranged at equal intervals along the axial direction of the first tubes.