JP2008279453A - Pipe junction structure and method for producing the structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pipe junction structure, which is simply composed to avoid generation of a temperature fluctuation section and to prevent damage to piping due to thermal fatigue and a method for producing the structure. <P>SOLUTION: The pipe junction structure is provided with a first piping 1 through which a fluid at a first temperature flows, a second piping 2 connected to the first piping 1, through which a fluid at a second temperature flows, and on the upstream side of the connection section of the second piping 2 with respect to the flow of the second fluid, a reducer 3 having a funnel-shaped member 3a extending from the inner wall of the second piping 2 to the downstream direction radially inwardly, wherein a member 3b with an approximately fixed diameter is provided extending to the first piping 1 on the downstream side of the end on the downstream side of the funnel-shaped member 3a and the member 3b is bent within the first piping 1 and further extends to the downstream direction with respect to the flow of the fluid at the first temperature. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a pipe junction structure that reduces the occurrence of thermal fatigue in a pipe through which a high-temperature fluid and a low-temperature fluid flow.

  Conventionally, many pipes are used in a plant. These pipes include a main pipe and a branch pipe connected to the main pipe, and form a pipe junction. Usually, a high-temperature fluid (for example, high-temperature water) or a low-temperature fluid (for example, low-temperature water) flows inside such a pipe. The temperature of these fluids varies depending on the application of the tube containing these fluids.

FIG. 18 is a longitudinal sectional view schematically showing a state in which the main pipe and the branch pipe are connected in such a conventional pipe junction. As shown in the figure, a branch pipe 102 is connected to the outer wall of the main pipe 101. In the main pipe 101 and the branch pipe 102, fluids having different temperatures flow in directions indicated by arrows a and b, respectively.
In addition, there exists the following patent document 1 as a thing relevant to such a prior art.
JP-A-60-220287

  However, in the configuration as shown in FIG. 18, the fluid flowing into the main pipe 101 from the branch pipe 102 in accordance with the flow rate difference and the temperature difference of the fluid flowing through the main pipe 101 and the branch pipe 102 respectively. In some cases, the flow of fluid flowing inside drifts downstream and collides with the inner wall of the main pipe 101. FIG. 6A shows a case where the fluid flowing into the main pipe 101 from the branch pipe 102 collides with the inner wall e on the side of the branch pipe 102 in the main pipe 101 as shown by an arrow c, and FIG. This is a case where the fluid flowing into the main pipe 101 from the branch pipe 102 collides with the inner wall f on the opposite side of the main pipe 101 from the branch pipe 102 as indicated by an arrow d.

  In such a case, fluids having different temperatures are not evenly mixed in the main pipe 101. Furthermore, temperature fluctuation portions in which the temperature fluctuates are formed on the inner walls e and f of the main pipe 101. That is, stress is generated so as to expand on the high temperature side of the inner walls e and f, and stress is generated so as to contract on the low temperature side. Therefore, the main pipe 101 is deformed at the inner walls e and f, and such stress is repeatedly generated, so that thermal fatigue may occur and the main pipe may be damaged. The temperature fluctuation is also called temperature fluctuation.

  In view of the above problems, the present invention provides a pipe merging portion structure that has a simple configuration, suppresses the occurrence of a temperature fluctuation portion, and prevents the pipe from being damaged due to thermal fatigue, and a method for manufacturing the same. The purpose is to do.

  To achieve the above object, according to the present invention, a first pipe through which a fluid at a first temperature flows, a second pipe connected to the first pipe and through which a fluid at a second temperature flows, A reducer having a funnel-like member extending radially inward and downstream from the inner wall of the second pipe on the upstream side of the connection portion of the second pipe with respect to the flow of the second fluid In the pipe junction part structure, a constant diameter member having a substantially constant diameter is provided extending to the first pipe further downstream from the downstream end of the funnel-shaped member, and the constant diameter member is the first diameter member. It is bent in the pipe and further extends in the downstream direction with respect to the flow of the fluid having the first temperature.

And it is characterized by satisfying the following conditions.
D _m : D _n = 1: (0.4 to 0.6)
L ₁ = (1.5 to 3.0) D _n
L ₂ = (0.5 to 1.5) D _b
However,
D _m : Inner diameter D 1 of the first pipe D _n : Inner diameter L ₁ of the reducer constant diameter member L ₁ : Distance from the central axis of the second pipe to the tip of the reducer constant diameter member L ₂ : Length of the funnel member of the reducer D _b is the inner diameter of the second pipe.

The funnel-shaped member may have a sinusoidal cross-sectional shape in the axial direction.
In addition, an R surface-shaped member that communicates the second pipe and the reducer is provided between the funnel-shaped member and the first pipe.

Further, a plurality of holes are formed in the wall surface near the tip of the constant diameter member.
Alternatively, the vicinity of the tip of the constant diameter member is a twisted pipe.

Alternatively, a swirling member for swirling the fluid is provided on at least one of the inside and outside of the constant diameter member.
The swivel member is a helical fin fixed between the constant diameter member and the first pipe.
Alternatively, the swiveling member is a twisted pipe disposed between the constant diameter member and the first pipe.
Alternatively, the swivel member is a guide vane extending radially between the constant diameter member and the first pipe.

The swivel member may be a guide vane extending radially within the constant diameter member. Alternatively, the swivel member is a helical fin disposed in the constant diameter member.
In addition, it is characterized in that there is provided a projecting portion that extends in the upstream direction with respect to the flow of the fluid at the first temperature from the bent portion of the constant diameter member, and whose surface is an axisymmetric streamline.

  Further, in the manufacturing method of the pipe junction part structure, a tee member in which the second pipe is connected to the first pipe and halved along the axial direction, and the bent constant diameter The elbow member having the role of member, the extended portion of the second pipe, and the funnel-like member of the reducer, the funnel-like member and the R-shaped member on the inside, and the second pipe portion on the outside A cylindrical member integrally formed, and the upstream end of the elbow member and the downstream end of the funnel-shaped member of the cylindrical member are welded all around to form the reducer, and the elbow member Between the tee members, and welding all the butted portions of the tee members, and the upstream end of the second piping portion of the combined tee member and the second piping portion of the cylindrical member. Downstream A Department characterized by circumferential welding.

  ADVANTAGE OF THE INVENTION According to this invention, it is possible to provide a pipe merging section structure that suppresses occurrence of a temperature fluctuation portion and prevents damage to the pipe due to thermal fatigue with a simple configuration.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a longitudinal sectional view schematically showing a pipe junction structure according to the first embodiment of the present invention. As shown in the figure, a branch pipe 2 is connected to the upper outer wall of the main pipe 1 extending to the left and right. As shown by the arrow A, high-temperature water flows through the main pipe 1 toward the right. In addition, low-temperature water flows through the branch pipe 2 and flows into the main pipe 1 downward and further to the right as indicated by an arrow B.

  In the main pipe 1, a reducer 3 is disposed substantially concentrically with respect to the central axis of the main pipe 1. The upstream end of the reducer 3 is connected to the inner wall of the main pipe 1 on the upstream side (left side in the drawing) of the main pipe 1 with respect to the connecting portion of the branch pipe 2. The diameter is reduced radially inward from the annular end toward the downstream side (the right side in the figure) to form a funnel-shaped portion 3a. Further, a constant diameter portion 3b having a substantially constant diameter from the downstream side in the main pipe 1 with respect to the connecting portion of the branch pipe 2, and further extends downstream. With this configuration, the high-temperature water in the main pipe 1 and the low-temperature water in the branch pipe 2 are prevented from being mixed at the pipe joint, and are merged downstream.

  Further, a spiral fin 4 extending in a spiral shape is fixed between the outer wall of the constant diameter portion 3b and the inner wall of the main pipe 1. As a result, the low-temperature water that has flowed into the main pipe 1 from the branch pipe 2 swirls along the spiral fin 4 around the constant diameter portion 3b as indicated by the arrow C, so that the main pipe 1 that has passed through the reducer 3 Mixing with hot water is promoted. Mixing of the low temperature water of the branch pipe 2 and the high temperature water of the main pipe 1 is performed on the downstream side of the constant diameter portion 3 b of the reducer 3. At this time, since the constant diameter portion 3b is arranged substantially concentrically with respect to the central axis of the main pipe 1, the mixed region S of high temperature water and low temperature water is near the center of the main pipe 1. Thereby, the occurrence of temperature fluctuation on the inner wall of the main pipe 1 is prevented.

  In addition, as described above, since the helical fin 4 is fixed between the outer wall of the constant diameter portion 3b and the inner wall of the main pipe 1, this also serves as an anti-sway of the reducer 3. However, the spiral fin 4 may be provided not only for the constant diameter portion 3b but also across the funnel portion 3a. In this embodiment, high temperature water flows through the main pipe 1 and low temperature water flows through the branch pipe 2. However, the present invention is not limited to this, and the high temperature side and the low temperature side may be reversed. . Moreover, it is not necessarily limited to water, The structure which another fluid flows may be sufficient. The same applies to the following embodiments.

  FIG. 2 is a longitudinal cross-sectional view schematically showing a pipe junction structure according to the second embodiment of the present invention. In this embodiment, as shown in the figure, a twisted pipe 5 is disposed between the constant diameter portion 3 b and the main pipe 1 instead of the spiral fin 4. This has a tubular shape with a corrugated helical structure on its inner and outer surfaces. Thereby, since the low temperature water which flowed into the main pipe 1 from the branch pipe 2 turns inside and outside the twisted pipe 5 as shown by an arrow C, mixing with the high temperature water of the main pipe 1 which has passed through the reducer 3 is prevented. Promoted. Alternatively, the constant diameter portion 3b itself may be a twisted pipe so that both the low temperature water and the high temperature water are swirled. Other configurations are the same as those in the first embodiment.

  FIG. 3 is a longitudinal sectional view schematically showing a pipe junction structure according to the third embodiment of the present invention. In the present embodiment, as shown in the drawing, the vicinity of the annular end 3 c on the upstream side of the funnel-like portion 3 a of the reducer 3 is shaped substantially parallel to the inner wall 1 a of the main pipe 1. As a result, a stagnation region T is provided between the vicinity of the annular end 3c and the inner wall 1a, so that new low-temperature water is hardly supplied to this portion so that the heat on the high-temperature water side is absorbed and held here, or Water having a temperature close to that of hot water is accumulated. As a result, a so-called thermal sleeve is formed, temperature fluctuation is reduced, and thermal shock on the inner wall 1a of the main pipe 1 is prevented. This configuration can be applied to any of the above-described or below-described embodiments having the reducer 3.

  FIG. 4 is a longitudinal cross-sectional view schematically showing a pipe junction structure according to the fourth embodiment of the present invention. In the present embodiment, as shown in the figure, a guide vane 6 is provided between the constant diameter portion 3 b of the reducer 3 and the main pipe 1 in place of the spiral fin 4 or the twisted pipe 5. As shown in FIG. 5, the guide vane 6 extends radially from the outer wall of the constant diameter portion 3 b to the inner wall of the main pipe 1. The guide vane 6 has a surface that forms a predetermined angle with respect to the flow direction.

  As a result, the low-temperature water that has flowed into the main pipe 1 from the branch pipe 2 turns around the constant diameter portion 3b as shown by the arrow C in FIG. 4, so that the high-temperature water of the main pipe 1 that has passed through the reducer 3 Mixing is promoted. In addition, since the guide vane 6 is fixed between the outer wall of the constant diameter portion 3b and the inner wall of the main pipe 1, this also serves as an anti-swaying function for the reducer 3. However, the guide vane 6 may be provided not only on the constant diameter portion 3b side but also on the funnel-shaped portion 3a side. Other configurations are the same as those in the above embodiments.

  FIG. 6 is a longitudinal sectional view schematically showing a pipe junction structure according to the fifth embodiment of the present invention. In this embodiment, as shown in the figure, in addition to the configuration of the first embodiment, a guide vane 7 is provided in the constant diameter portion 3b of the reducer 3. As shown in FIG. 7 by enlarging the EE cross section of FIG. 7, the guide vanes 7 extend radially from the inner wall of the constant diameter portion 3b to the hub 8 at the center. The guide vane 7 has a surface that forms a predetermined angle with respect to the flow direction.

  Thereby, since the high temperature water which has passed through the reducer 3 swirls inside the constant diameter portion 3b, mixing with the low temperature water which has passed around the reducer 3 is promoted. In addition, when the pressure loss by the hub 8 is large, it is good also as a structure which deletes this and each guide vane 7 is extended to the central axis part of the constant diameter part 3b, and was mutually connected by the front-end | tip. Moreover, the guide vane 7 may be provided not only on the constant diameter portion 3b side but also on the funnel-shaped portion 3a side. Moreover, in addition to the structure of the said 2nd-4th embodiment, the guide vane 7 can also be provided. Furthermore, a spiral fin may be provided instead of the guide vane 7.

  FIG. 8 is a longitudinal sectional view schematically showing a pipe junction structure according to the sixth embodiment of the present invention. This embodiment has a configuration corresponding to a so-called collision merging type. That is, as shown in the figure, the reducer 3 is a so-called bend-type reducer that is bent toward the branch pipe 2 that is the downstream side after joining. In this case, the funnel-shaped part 3 a of the reducer 3 is bent in the vicinity of the connection part of the branch pipe 2, and the constant diameter part 3 b extends into the branch pipe 2.

  The high-temperature water that has flowed to the right as indicated by arrow A in the main pipe 1 is bent in the reducer 3 and flows into the branch pipe 2. On the other hand, the low-temperature water flowing toward the left as indicated by the arrow B in the main pipe 1 flows into the branch pipe 2 through the outside of the reducer 3. Here, since the helical fin 4 extending in a spiral shape is fixed between the outer wall of the constant diameter portion 3b and the inner wall of the branch pipe 2, the low-temperature water flowing into the branch pipe 2 from the main pipe 1 Turn around 3b. Thereby, mixing with the high temperature water which has passed through the reducer 3 is promoted.

  The mixing of the low temperature water and the high temperature water is performed on the downstream side of the constant diameter portion 3 b of the reducer 3, and then flows through the branch pipe 2 as indicated by an arrow F. At this time, since the constant diameter portion 3 b is disposed substantially concentrically with respect to the central axis of the branch pipe 2, the mixed region of the high temperature water and the low temperature water is near the center of the branch pipe 2. Thereby, the occurrence of temperature fluctuation on the inner wall of the branch pipe 2 is prevented.

  FIG. 9 is a longitudinal sectional view schematically showing a pipe junction structure according to the seventh embodiment of the present invention. In the present embodiment, as shown in the figure, in addition to the configuration of the sixth embodiment, a plurality of rectifying plates 9 having a shape along the bent shape are arranged at a predetermined interval in the bent portion in the reducer 3. is doing. Alternatively, a single arrangement may be used. This prevents high-temperature water flowing in the reducer 3 from causing a secondary flow such as causing a drift in the bent portion and winding the vortex.

  FIG. 10 is a longitudinal sectional view schematically showing a pipe junction structure according to the eighth embodiment of the present invention. As shown in the figure, a branch pipe 2 is connected substantially orthogonally to the right outer wall of the main pipe 1 extending vertically. High temperature water flows through the main pipe 1 as indicated by an arrow A upward. Further, low-temperature water flows through the branch pipe 2, which flows into the main pipe 1 along the reducer 3 below as shown by an arrow B toward the left and further upward.

  In the branch pipe 2, the reducer 3 is disposed substantially concentrically with respect to the central axis of the branch pipe 2. The upstream annular end of the reducer 3 is connected to the inner wall of the branch pipe 2 on the upstream side (right side in the drawing) of the branch pipe 2 from the connecting portion of the branch pipe 2. The diameter is reduced radially inward from the annular end toward the downstream side (left side in the figure), thereby forming a funnel-shaped portion 3a. Further, a constant diameter portion 3 b having a substantially constant diameter is formed from the vicinity of the connection portion of the branch pipe 2 and extends to the main pipe 1.

  The constant diameter portion 3b is bent into a substantially L shape in the main pipe 1, and further extends from the bent portion in the downstream direction (the upper side in the figure). With this configuration, the high-temperature water in the main pipe 1 and the low-temperature water in the branch pipe 2 are prevented from being mixed at the pipe joint, and are merged downstream. At this time, since the portion further extending from the bent portion of the constant diameter portion 3b is disposed substantially concentrically with respect to the central axis of the main pipe 1, the mixed region of the high temperature water and the low temperature water is near the center of the main pipe 1. Thereby, the occurrence of temperature fluctuation on the inner wall of the main pipe 1 is prevented. Moreover, the axial cross-sectional shape of the funnel-shaped portion 3a is a sinusoidal curve that gradually begins to shrink radially inward on the upstream side and gradually converges on the downstream side. The flow is as smooth as possible.

  In addition, an R-surface shape portion 3 d that connects the branch pipe 2 and the reducer 3 is provided between the funnel-shaped portion 3 a and the main pipe 1, and an inner diameter surface thereof faces the main pipe 1 side. By providing such an R surface, the thermal stress concentration is reduced. Further, a stagnation region T is formed in the branch pipe 2 between the R-surface shaped portion 3d and the main pipe 1, and the high temperature water in the main pipe 1 is stagnated in this part, so that it is difficult to supply new high temperature water. In this way, heat is released from here to the low-temperature water side, so that water having a temperature close to low-temperature water is accumulated to some extent. As a result, a so-called thermal sleeve is formed, temperature fluctuations are reduced, and thermal impact on the inner wall 2a of the branch pipe 2 is prevented.

In the present embodiment, as shown in the figure, an effective countermeasure against temperature fluctuation is obtained by defining a predetermined numerical range using the dimensions of each part of the pipe junction as a parameter. Specifically, the configuration satisfies the following conditions.
Dm: Dn = 1: (0.4 to 0.6)
L1 = (1.5-3.0) Dn
L2 = (0.5-1.5) Db

However,
Dm: inner diameter Dn of the main pipe 1 Dn: inner diameter L1 of the constant diameter part 3b of the reducer 3 L1: distance from the central axis of the branch pipe 2 to the tip of the constant diameter part 3b of the reducer 3 L2: the length Db of the funnel-shaped part 3a of the reducer 3 : The inner diameter of the branch pipe 2.

  Thereby, the temperature fluctuation | variation in a piping confluence | merging part can be suppressed effectively. In the present embodiment, it is assumed that the inner diameter Dm of the main pipe 1 and the inner diameter Db of the branch pipe 2 are in a ratio of 1: 1, but the present invention is not limited to this. The same applies to the embodiments described later.

  FIG. 11 is a graph schematically showing the state of temperature fluctuation in the pipe junction. Here, the horizontal axis indicates the distance x (shown in FIG. 10) in the downstream direction in the main pipe 1 from the central axis of the branch pipe 2, and the vertical axis indicates the temperature fluctuation width Δt. The temperature is measured near the inner wall of the main pipe 1. Moreover, this is set to 1.0 on the basis of the temperature difference between the high temperature water and the low temperature water.

  In the figure, a curve α shows a case where no measures for temperature fluctuation are taken at the pipe junction, that is, a case where only the branch pipe 2 is connected to the main pipe 1. In this case, since the high temperature water and the low temperature water collide and merge at the position of the central axis of the branch pipe 2 and the vicinity thereof, the temperature fluctuates in the temperature range from the high temperature water to the low temperature water, and the temperature fluctuation range Δt = 1. 0. And as it leaves | separates from the center axis line of the branch pipe 2, since high temperature water and low temperature water are mixed, the temperature fluctuation width becomes small and it approaches 0.

  On the other hand, a curve β indicates a case where a measure for temperature variation is taken at the pipe junction. In this case, the position of the tip of the constant diameter portion 3b of the reducer 3, that is, the position of the distance L1 from the central axis of the branch pipe 2, is used as the reference point for merging. Since they gradually merge while flowing in the same direction, the temperature variation width is 30 to 40% smaller at the initial position of the merge as compared with the case where no countermeasure for temperature variation is taken. In this way, temperature fluctuations at the pipe junction are effectively suppressed. Thereafter, as the distance from the tip of the constant diameter portion 3b is increased, the high temperature water and the low temperature water are mixed, so that the temperature fluctuation width is further reduced and approaches zero.

  FIG. 12 is a longitudinal sectional view schematically showing a pipe junction structure according to the ninth embodiment of the present invention. In this embodiment, as shown in the figure, in addition to the configuration of the eighth embodiment, a plurality of holes h are formed in the wall surface near the tip of the constant diameter portion 3b of the reducer 3 to form a so-called perforated plate. Yes. Thereby, before the low temperature water of the reducer 3 comes out from the front-end | tip of the constant diameter part 3b, since it is gradually mixed with the high temperature water of the main pipe 1 through the hole h, the temperature fluctuation range is further reduced.

  FIG. 13 is a longitudinal sectional view schematically showing a pipe junction structure according to the tenth embodiment of the present invention. In the present embodiment, as shown in the figure, in addition to the configuration of the eighth embodiment, a guide (swivel) vane between the constant diameter portion 3b and the main pipe 1 in the same manner as the fourth embodiment. 6 is provided. The guide (swivel) vanes 6 extend radially from the outer wall of the constant diameter portion 3b to the inner wall of the main pipe 1. The guide (turning) vane 6 has a surface that forms a predetermined angle with respect to the flow direction.

  Thereby, since the high temperature water of the main pipe 1 swirls around the constant diameter portion 3b, mixing with the low temperature water that has passed through the reducer 3 is promoted. Further, since the guide (turning) vane 6 is fixed between the outer wall of the constant diameter portion 3b and the inner wall of the main pipe 1, this also serves as an anti-sway of the reducer 3. Other configurations are the same as those of the eighth and ninth embodiments.

  FIG. 14 is a longitudinal sectional view schematically showing a pipe junction structure according to the eleventh embodiment of the present invention. In the present embodiment, as shown in the figure, in addition to the configuration of the eighth embodiment, a guide (turning) vane 7 is provided in the constant diameter portion 3b in the same manner as the fifth embodiment. Yes. The guide (swivel) vanes 7 extend radially from the inner wall of the constant diameter portion 3b to the center. The guide (turning) vane 7 has a surface that forms a predetermined angle with respect to the flow direction. Thereby, since the low temperature water which has passed through the reducer 3 swirls inside the constant diameter portion 3b, mixing with the high temperature water which has passed around the reducer 3 is promoted. In addition to the configurations of the ninth and tenth embodiments, a guide (turning) vane 7 can be provided.

  FIG. 15 is a longitudinal sectional view schematically showing a pipe junction structure according to the twelfth embodiment of the present invention. In the present embodiment, as shown in the figure, in addition to the configuration of the eighth embodiment, the vicinity of the tip of the constant diameter portion 3b of the reducer 3 is twisted in the same manner as that illustrated in the second embodiment. 3ba. The twisted pipe has a tubular shape having a corrugated spiral structure on the inner and outer surfaces thereof. Thereby, since both the low temperature water which has passed through the reducer 3 and the high temperature water of the main pipe 1 are swirled, mixing is promoted. Or you may arrange | position a twisted piping separately between the constant diameter part 3b and the main pipe 1. FIG.

  FIG. 16: is a longitudinal cross-sectional view which shows typically the piping junction part structure which concerns on the 13th Embodiment of this invention. In the present embodiment, as shown in the figure, in addition to the configuration of the eighth embodiment, a protrusion 10 extending from the bent portion of the constant diameter portion 3b of the reducer 3 to the upstream side of the high-temperature water in the main pipe 1. Is provided. The protrusion 10 has an axisymmetric streamlined surface, thereby reducing the resistance caused by the pipe junction structure of the present invention to the high-temperature water flowing through the main pipe 1 and suppressing pressure loss.

  In addition, although not illustrated, in addition to the configuration of the eighth embodiment, a spiral fin may be provided on the outside, the inside, or both of the constant diameter portion 3b of the reducer 3.

  FIG. 17 is a perspective view showing a specific example of the pipe junction structure according to each of the eighth and subsequent embodiments of the present invention. The figure (a) is an overall view, and the figure (b) is an exploded view. The pipe junction part structure of the present invention has tee members 11a and 11b that halve along the axial direction the branch pipe 2 connected to the main pipe 1 as shown in FIG. The elbow member 12 having the role of the constant diameter portion 3b bent into a substantially L shape of the reducer 3 is sandwiched between them. In the figure, the elbow members 12 in the tee members 11a and 11b are indicated by solid lines. Further, as shown in FIG. 19, there is a method of dividing the tee member into two parts up and down like 11c and 11d.

  In addition, on the upstream side of the branch pipe 2 portion of the tee members 11a and 11b, a cylindrical member 13 having a role of an extension part of the branch pipe 2 and a funnel-like part 3a of the reducer 3 extends. The cylindrical member 13 includes a funnel-shaped portion 3a and an R-surface shape portion 3d on the inner side and a branch pipe 2 portion on the outer side, and these are integrally formed as a casting. The material is mainly cast steel. Alternatively, it may be manufactured by cutting a columnar or cylindrical member. The material of the other members is mainly stainless steel. However, it is not limited to such a material.

  As a specific manufacturing method of the pipe junction portion structure of the present invention, in FIG. 2B, first, the upstream end portion of the elbow member 12 and the downstream end portion of the funnel-shaped portion 3a of the cylindrical member 13 are all assembled. Circumferential welding is performed to form the reducer 3. Then, the elbow member 12 is sandwiched between the tee members 11a and 11b, and all butted portions of the tee members are welded, and the upstream end of the branch pipe 2 portion of the combined tee members 11a and 11b and the cylindrical member 13 are branched. The entire circumference of the downstream end of the pipe 2 is welded.

  Note that the first pipe in the claims corresponds to the main pipe 1 in the embodiment, and the second pipe corresponds to the branch pipe 2. The first temperature fluid corresponds to high temperature water, and the second temperature fluid corresponds to low temperature water. However, as described above, it is not limited to the correspondence relationship of such an embodiment.

The longitudinal cross-sectional view which shows the piping confluence | merging part structure of 1st Embodiment. The longitudinal cross-sectional view which shows the piping confluence | merging part structure of 2nd Embodiment. The longitudinal cross-sectional view which shows the piping junction part structure of 3rd Embodiment. The longitudinal direction sectional view showing the pipe junction part structure concerning a 4th embodiment. DD sectional drawing of FIG. The longitudinal cross-sectional view which shows the piping confluence | merging part structure of 5th Embodiment. EE sectional drawing of FIG. The longitudinal direction sectional view showing the pipe junction part structure of a 6th embodiment. The longitudinal cross-sectional view which shows the piping confluence | merging part structure of 7th Embodiment. The longitudinal direction sectional view showing the pipe junction part structure of an 8th embodiment. The graph which shows the mode of the temperature fluctuation in a piping confluence | merging part. The longitudinal cross-sectional view which shows the piping confluence | merging part structure of 9th Embodiment. The longitudinal direction sectional view showing the pipe junction part structure of a 10th embodiment. The longitudinal cross-sectional view which shows the piping confluence | merging part structure of 11th Embodiment. The longitudinal cross-sectional view which shows the piping confluence | merging part structure of 12th Embodiment. The longitudinal cross-sectional view which shows the piping confluence | merging part structure of 13th Embodiment. The perspective view which shows the specific example of the piping confluence | merging part structure of this invention. The longitudinal cross-sectional view which shows the state by which the main pipe and the branch pipe are connected in the conventional piping confluence | merging part. The perspective view which shows the other division | segmentation method of a tee member.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Main pipe 2 Branch pipe 3 Reducer 4 Spiral fin 5 Twist piping 6, 7 Guide vane 8 Hub 9 Current plate 10 Protrusion part 11a, 11b Tee member 12 Elbow member 13 Cylindrical member S Mixing area T Stagnation area

Claims (14)

A first pipe through which a fluid at a first temperature flows;
A second pipe connected to the first pipe and through which a fluid of a second temperature flows;
A reducer having a funnel-like member extending radially inward and downstream from the inner wall of the second pipe on the upstream side of the connection portion of the second pipe with respect to the flow of the second fluid. In the pipe junction structure
Extending further downstream from the downstream end of the funnel-shaped member to the first pipe, providing a constant diameter member having a substantially constant diameter, the constant diameter member is bent in the first pipe, A pipe junction structure that further extends in the downstream direction with respect to the flow of the fluid at the first temperature. The pipe junction structure according to claim 1, wherein the following condition is satisfied.
D _m : D _n = 1: (0.4 to 0.6)
L ₁ = (1.5 to 3.0) D _n
L ₂ = (0.5 to 1.5) D _b
However,
D _m : Inner diameter D 1 of the first pipe D _n : Inner diameter L ₁ of the reducer constant diameter member L ₁ : Distance from the central axis of the second pipe to the tip of the reducer constant diameter member L ₂ : Length of the funnel member of the reducer D _b is the inner diameter of the second pipe.   The pipe junction part structure according to claim 1 or 2, wherein an axial cross-sectional shape of the funnel-shaped member is a sinusoidal curve.   4. An R surface-shaped member that communicates the second pipe and the reducer is provided between the funnel-shaped member and the first pipe. The piping junction structure described.   The piping junction structure according to any one of claims 1 to 4, wherein a plurality of holes are formed in a wall surface in the vicinity of the distal end of the constant diameter member.   The pipe junction part structure according to any one of claims 1 to 4, wherein the vicinity of the tip of the constant diameter member is a twisted pipe.   The pipe junction part structure according to any one of claims 1 to 4, wherein a turning member for turning a fluid is provided on at least one of the inside and outside of the constant diameter member.   The pipe junction part structure according to claim 7, wherein the swivel member is a helical fin fixed between the constant diameter member and the first pipe.   The pipe junction part structure according to claim 7, wherein the turning member is a twisted pipe disposed between the constant diameter member and the first pipe. The pipe junction part structure according to claim 7, wherein the turning member is a guide vane extending radially between the constant diameter member and the first pipe.   The pipe junction part structure according to any one of claims 7 to 10, wherein the swivel member is a guide vane extending radially within the constant diameter member.   The pipe junction part structure according to any one of claims 7 to 10, wherein the turning member is a helical fin disposed in the constant diameter member.   The protrusion part extended in the upstream direction with respect to the flow of the fluid of the said 1st temperature from the bending part of the said constant diameter member, and the surface provided the axially symmetrical streamlined part. Item 13. The pipe junction structure according to any one of Items 12. It is a manufacturing method of the pipe merge part structure according to any one of claims 1 to 13,
A tee member in which the second pipe is connected to the first pipe in half along the axial direction;
An elbow member having the role of the bent constant diameter member;
Cylindrical member having an extension of the second pipe and a funnel-like member of the reducer, the funnel-like member and the R-shaped member on the inner side, and the second pipe part on the outer side. And
The upstream end of the elbow member and the downstream end of the funnel-shaped member in the cylindrical member are welded all around to form the reducer, the elbow member is sandwiched between the tee members, and the tee members are butted together All the parts are welded, and the upstream end of the second pipe part in the combined tee member and the downstream end of the second pipe part of the cylindrical member are welded all around. A method for manufacturing a pipe junction structure.

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