JPH07108332A - Hydraulic tube expanding tool - Google Patents

Abstract

PURPOSE:To increase tolerance against the variations of a tube hole and to enlarge the range of tube expansion to the surface flush with a tube plate. CONSTITUTION:A second soft elastic body 29 and hard elastic body 30 are provided between a first soft elastic body 28 and a collar ring 27. Even with some variations in a space 25 between a tube hole 22 and a tube 23, the tube 23 is closely made adhered to the tube hole 22 on the surface of a tube plate 21 without changing the diameter of the collar ring 27; the projection is prevented of the second soft elastic body 29 to the collar ring 27 side; tolerance is increased against the variations of the tube hole; and the range of tube expansion is enlarged to the surface flush with the tube plate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic pipe expanding tool for fixing a heat transfer tube to a tube plate of a heat exchanger such as a steam generator.

[0002]

2. Description of the Related Art When fixing a heat transfer tube to a tube plate of a heat exchanger such as a steam generator, a heat transfer tube inserted into a hole of the tube plate is often expanded by hydraulic expansion. A conventional hydraulic pipe expanding tool used for this will be described with reference to FIGS. 7 and 8. FIG. 7 is a sectional view before pipe expansion, and FIG. 8 is a sectional view after pipe expansion.

As shown in FIG. 7, a heat transfer tube 3 is inserted into a tube hole 2 of a tube sheet 1, and a hydraulic expansion tool (tool) 4 is inserted into the heat transfer tube 3. The heat transfer tube 3 is expanded by the tool 4, the gap 5 between the tube hole 2 and the heat transfer tube 3 disappears, and the two are brought into close contact with each other. The tool 4 includes a mandrel 6, and a collar ring 7 is fixed to an end of the mandrel 6. A first elastic body 8 for initial pressure sealing is fitted to the outer periphery of the mandrel 6, and a second elastic body 9 for high pressure sealing is fitted to the outer periphery of the mandrel 6 between the collar ring 7 and the first elastic body 8. Have been combined. A liquid injection hole 10 is formed in the mandrel 6, and the liquid is injected into a gap 12 between the inner circumference of the heat transfer tube 3 and the outer circumference of the mandrel 6 by a liquid injection / pressurization device (not shown).

As shown in FIGS. 7 and 8, when liquid is injected into the gap 12 from the liquid injection hole 10 by a liquid injection / pressurization device (not shown), the liquid is filled in the gap 12 whose lower end is closed and the internal pressure 13 is increased. Occur. When the internal pressure 13 is generated, the first elastic body 8 moves and begins to apply a force to the second elastic body 9,
When liquid is further injected, the internal pressure 13 rises and the first elastic body 8
At the same time, the second elastic body 9 elastically deforms. The deformed second elastic body 9 starts contacting the inner surface 3a of the heat transfer tube 3 to start deforming the heat transfer tube 3. When expanding, the tube plate 1 is further elastically deformed after the heat transfer tube 3 contacts the inner surface 2a of the tube hole 2. It is done up to that point.
As a result, the heat transfer tube 3 is closely fixed to the tube hole 2 by spring back from the tube sheet 1. At the time of pipe expansion, the protrusion of the first elastic body 8 and the second elastic body 9 to the outside is prevented by the color ring 7, and the pipe expansion allowance 14 is adjusted and controlled by the color ring 7.

[0005]

When the pipe 4 is expanded by using the above-mentioned tool 4, when the gap 5 between the heat transfer pipe 3 and the tube hole 2 becomes large, the inner surface 3a of the heat transfer pipe 3 and the color ring 7 after the pipe expansion. In some cases, the gap 15 with the outer circumference becomes large, and the first elastic body 8 and the second elastic body 9 may protrude upward beyond the upper surface of the tube sheet 1. When the first elastic body 8 and the second elastic body 9 project to the outside of the tube sheet 1, bulging (bulging) occurs in the heat transfer tube 3 or the corner portion 7a of the color ring 7 of the second elastic body 9 is formed. There is a problem that a crack is generated at the contact and the life of the second elastic body 9 is shortened. In order to prevent the bulge of the heat transfer tube, it is necessary to set the tool 4 so that the lower end of the color ring 7 is inside the surface 1a of the tube sheet 1. When the lower end of the color ring 7 is located inside the surface 1 a of the tube sheet 1, a gap 16 remains between the tube hole 2 and the heat transfer tube 3, and this gap 16
There is a possibility that the feed water may enter the tank and the impurities in the feed water may be chemically concentrated to damage the heat transfer tube 3.

In order to solve these problems, it is necessary to control the gap 15 between the inner surface 3a of the heat transfer tube 3 and the outer circumference of the collar ring 7 after expansion to be small. For this purpose, it is necessary to measure the inner diameter of the tube hole 2 in advance and set the diameter of the collar ring 7 for each tube hole 2 based on the data, which is a cost for fixing the heat transfer tube 3 and The time had increased.

[0007]

According to the structure of the first invention for solving the above-mentioned problems, a diameter-increased portion is formed at the distal end portion, a liquid injection passage is formed inside, and the liquid injection passage is a shaft portion. A mandrel opened at the center, a backup collar ring fitted to the shaft portion of the mandrel in a state where the back surface is in contact with the expanded diameter portion, and the liquid injection passage opened by being fitted to the shaft portion of the mandrel. In a hydraulic expansion tool having an annular first soft elastic body facing the liquid space, the annular second soft elastic body in contact with the back surface of the first soft elastic body and the back surface of the second soft elastic body An annular hard elastic body is provided between the backup collar ring and the first soft elastic body.

Further, in the structure of the second invention for solving the above-mentioned problems, a diameter-increased portion is formed at the tip end, a liquid injection passage is formed inside, and the liquid injection passage is opened at the center of the shaft portion. A mandrel, a backup collar ring fitted to the shaft of the mandrel in a state where the back surface is in contact with the expanded diameter portion, and a liquid space fitted to the shaft of the mandrel and having the liquid injection passage opened. In a hydraulic expansion tool having an annular soft elastic body facing, a hard elastic body having a taper portion and a cylindrical straight portion whose diameter is reduced toward the backup collar ring, the backup collar ring and the It is characterized in that it is provided between the soft elastic body.

[0009]

According to the first aspect of the present invention, the second soft elastic body is elastically deformed in response to the elastic deformation of the first soft elastic body due to the initial hydraulic pressure, and the second soft elastic body applies a force to the hard elastic body. As a result, the soft elastic body applies internal pressure to the tube while being elastically deformed and not expanded. At this time, a frictional force is generated between the second soft elastic body and the hard elastic body and between the contact surfaces of the hard elastic body and the color ring, and the end surface of the hard elastic body on the side of the second soft elastic body is piped by the radial force. It deforms along the shape of the inner surface of the tube, and there is no gap between the tube hole and the tube.
The soft elastic body is pressed against the hard elastic body.

According to the second aspect of the invention, the hard elastic body is elastically deformed and expanded in diameter in response to the elastic deformation of the soft elastic body due to the initial hydraulic pressure. Since the hard elastic body has the taper portion whose diameter decreases toward the coloring side, the soft elastic body first comes into contact with the inner surface of the tube to expand the tube by the surface pressure in the radial direction. As the diameter of the hard elastic body increases, the surface pressure increases and forms a smooth pipe end. The hardness and outer diameter of the hard elastic body are set according to the range of the pipe expansion ratio.

[0011]

1 is a sectional view of a hydraulic pipe expanding tool according to an embodiment of the first invention before pipe expansion, and FIG. 2 is a sectional view thereof after pipe expansion.

As shown in FIG. 1, a heat transfer tube 23 is inserted into a tube hole 22 of a tube plate 21, and a liquid pressure expanding tool (tool) 24 according to the present invention is inserted into the heat transfer tube 23. Heat transfer tube 23
Is expanded by a tool 24, and the gap 25 between the tube hole 22 and the heat transfer tube 23 disappears so that they are in close contact with each other. The tool 24 includes a mandrel 26 having a diameter-expanded portion 26a formed at its tip,
A backup color ring (color ring) 27 is fixed to the end of the shaft portion 26b of the mandrel 26.
A first soft elastic body 28 for initial hydraulic sealing is fitted on the outer periphery of the mandrel 26, and a high pressure hydraulic sealing is provided on the outer periphery of the mandrel 26 between the collar ring 27 and the first soft elastic body 28. The second soft elastic body 29 is fitted. The second soft elastic body 29 expands the diameter according to the elastic deformation of the first soft elastic body 28 to expand the heat transfer tube 23, and the second soft elastic body 29 is set to be harder than the first soft elastic body 28. There is. Further, the second soft elastic body 29 and the coloring ring 27
A hard elastic body 30 is provided on the outer periphery of the mandrel 26 between
Are fitted, and the hard elastic body 30 elastically deforms in accordance with the elastic deformation of the second soft elastic body 29. The hard elastic body 30 elastically deforms in a state in which the heat transfer tube 23 is not expanded and a state in which the second soft elastic body 29 is prevented from protruding toward the collar ring 27 side.
Further, the mandrel 26 is formed with a liquid injection hole 31 as a liquid injection passage opening at the center of the shaft portion 26b, and the inner circumference 23 of the heat transfer tube 23 is formed by a liquid injection / pressurizing device (not shown).
The liquid is injected into the gap 32 (liquid space) between a and the outer periphery of the mandrel 26. That is, the collar ring 27 is fitted to the shaft portion 26b of the mandrel 26 with the back surface in contact with the expanded diameter portion 26a, and the first soft elastic body 28 faces the gap 32 which is a liquid space and the shaft portion of the mandrel 26. 26b
Is fitted to. Further, the second soft elastic body 29 is in contact with the back surface of the first soft elastic body 28, and the hard elastic body 30 is in contact with the back surface of the second soft elastic body 29. A second soft elastic body 29 and a hard elastic body are provided between them.

As shown in FIGS. 1 and 2, when liquid is injected into the gap 32 from the liquid injection hole 31 by a liquid injection / pressurization device (not shown), the liquid is filled in the gap 32 whose lower end is closed and the internal pressure 33 is increased. Occur. When the internal pressure 33 is generated, the first soft elastic body 28 moves in the axial direction to move the second soft elastic body 2
When a force is started to be applied to 9 and the liquid is further injected, the internal pressure 33 rises and a compressive force is applied to the second soft elastic body 29 and the hard elastic body 30. From the point where the internal pressure 33 exceeds the yield stress of the heat transfer tube 23 (point A in FIG. 3), the heat transfer tube 23 starts plastic deformation. When the heat transfer tube 23 contacts the inner surface 22a of the tube hole 22, the internal pressure 33 rapidly increases (point B in FIG. 3). When the tube sheet 21 is elastically deformed and reaches the point C in FIG. 3, the hard elastic body 30 is expanded following the second soft elastic body 29.
Since there is no radial force to deform the heat transfer tube 23, the heat transfer tube 23 is expanded to the state shown in FIG. That is, the hard elastic body 30
Deforms along the shape of the inner surface of the heat transfer tube 23, no gap is created between the tube hole 22 and the heat transfer tube 23, and the second soft elastic body 29 is pressed by the hard elastic body 30. Then, by unloading the internal pressure 33, the heat transfer tube 23 is brought into close contact with the tube hole 22 by spring back from the tube sheet 21 (point D in FIG. 3).

In the tool 24 described above, the second soft elastic body 2 is used.
By including 9 and the hard elastic body 30, even if there is some variation in the gap 25 between the tube hole 22 and the heat transfer tube 23,
The heat transfer tube 23 can be brought into close contact with the tube hole 22 of the surface of the tube plate 21 without changing the diameter of the color ring 27, and the second elastic body 29 is prevented from protruding toward the color ring 27. You can

Next, an embodiment of the second invention will be described with reference to FIGS. FIG. 4 is a sectional view of a hydraulic pipe expanding tool according to an embodiment of the second invention before pipe expansion, FIG. 5 is a sectional view after pipe expansion, and FIG. 6 is an enlarged view of an arrow VI portion in FIG.

As shown in FIG. 4, a heat transfer tube 43 is inserted into the tube hole 42 of the tube plate 41, and the hydraulic pressure expanding tool (tool) 44 according to the present invention is inserted into the heat transfer tube 43. Heat transfer tube 43
Is expanded by a tool 44, and the gap 45 between the tube hole 42 and the heat transfer tube 43 is eliminated, and the two are brought into close contact with each other. The tool 44 includes a mandrel 46 having a diameter-expanded portion 46a formed at a tip end thereof,
A backup coloring (coloring) 47 is fixed to the end of the shaft portion 46b of the mandrel 46.
A soft elastic body 48 for initial hydraulic sealing is fitted on the outer periphery of the mandrel 46, and the collar ring 47 and the soft elastic body 48 are fitted.
A hard elastic body 49 is provided on the outer periphery of the mandrel 46 between
Are fitted. The hard elastic body 49 expands in diameter in accordance with the elastic deformation of the soft elastic body 48 to form a pipe expansion end, and the outer diameter gradually decreases toward the collar ring 47 side (diameter reduction). It is composed of a tapered portion 49b. A liquid injection hole 50 is formed in the mandrel 46 as a liquid injection passage opening at the center of the shaft portion 46b. The liquid injection / pressurizing device (not shown) is provided between the inner circumference 43a of the heat transfer tube 43 and the outer circumference of the mandrel 46. The liquid is injected into the gap 51 (liquid space). That is, the collar ring 47 is fitted to the shaft portion 46b of the mandrel 46 with the back surface in contact with the expanded diameter portion 46a, and the soft elastic body 48 is attached to the shaft portion 46b of the mandrel 46 while facing the gap 51 which is a liquid space. Fitted, the collar ring 47 and the soft elastic body 4
A hard elastic body 49 is provided between the two.

As shown in FIGS. 4 to 6, when a liquid is injected into the gap 51 from the liquid injection hole 50 by a liquid injection / pressurization device (not shown), the soft elastic body 48 moves in the axial direction by the liquid. When liquid is filled in the gap 51 whose lower end is closed and the internal pressure 52 is generated, an axial force is applied to the hard elastic body 49 according to elastic deformation of the soft elastic body 48. Due to this force, the hard elastic body 49 elastically deforms from the color ring 47 side having a small cross-sectional area. The heat transfer tube 43 plastically deforms when the internal pressure 52 and the surface pressure from the hard elastic body 49 exceed the yield stress of the heat transfer tube 43. When the heat transfer tube 43 contacts the inner surface 42a of the tube hole 42, the internal pressure 52 suddenly rises and the tube sheet 41 elastically deforms. As a result, the heat transfer tube 43 after unloading will be
The spring back from 1 makes close contact with the tube hole 42.

The surface pressure applied from the hard elastic body 49 to the inner surface 42a of the tube hole 42 is uniform in the straight portion 49a, but the restoring force increases as the amount of elastic deformation increases in the tapered portion 49b. Therefore, in the taper portion 49b, the surface pressure in the radial direction is small, and a surface pressure difference occurs in a state where the surface pressure gradually approaches the surface pressure of the straight portion 49a, and the surface pressure is changed.
Pipe expansion occurs where the yield stress of 3 is exceeded. When expanded, the radial force 53 of the hard elastic body 49 is released, and the restoring force and the hardness of the heat transfer tube 43 are balanced and the deformation is stopped. Therefore, by appropriately setting the shape and hardness of the hard elastic body 49 according to the tube expansion rate and the tube expansion pressure, as shown in FIG. 5, the heat transfer tube 43 at the end of the tube hole 42 is expanded in a gently changing shape. Can be the edge.

In the above-described tool 44, since the hard elastic body 49 is composed of the straight portion 49a and the tapered portion 49b, even if there is some variation in the gap 45 between the tube hole 42 and the heat transfer tube 43, the collar ring 47 is formed. The heat transfer tube 43 can be brought into close contact with the tube hole 42 on the surface of the tube sheet 41 without changing the diameter of the tube, and the soft elastic body 48 can be prevented from protruding toward the collar ring 47. Furthermore, since the pipe expansion end can be formed into a gently changing diameter, residual stress can be reduced.

[0020]

In the hydraulic pipe expanding tool of the first aspect of the present invention, since the second soft elastic body and the hard elastic body are provided, even if there is some variation in the gap between the pipe hole and the pipe, the diameter of the color ring is small. It is possible to fit the tube to the tube hole on the tube plate surface without any gap without changing the above, and to prevent the second soft elastic body from protruding toward the coloring side. As a result, the tolerance for tube hole variation is increased, the sealing performance is improved, and high-pressure pipe expansion is possible, and the expansion range can be expanded to the tube plate surface, reducing the amount of clevis and reducing the chemical substances in the clevis part. Can be prevented from concentrating, and the life of heat exchangers can be extended.

Further, in the hydraulic pressure expanding tool of the second invention, since the outer diameter of the hard elastic body is gradually reduced toward the coloring side, even if there is some variation in the gap between the pipe hole and the pipe,
The pipe can be brought into close contact with the pipe hole on the pipe sheet surface without changing the diameter of the coloring ring, and the soft elastic body can be prevented from protruding toward the coloring ring. As a result, the tolerance for tube hole variation is increased, the sealing performance is improved, and high-pressure pipe expansion is possible, and the expansion range can be expanded to the tube plate surface, reducing the amount of clevis and reducing the chemical substances in the clevis part. Can be prevented from concentrating, and the life of heat exchangers can be extended. Further, since the pipe expansion end can be formed into a gently changing diameter, residual stress can be reduced and the life of the heat exchanger and the like can be extended.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a hydraulic pipe expanding tool according to an embodiment of the first invention before pipe expansion.

FIG. 2 is a sectional view of the hydraulic pressure expanding tool according to the embodiment of the first invention after pipe expansion.

FIG. 3 is a graph showing the relationship between the internal pressure and the pipe expansion amount.

FIG. 4 is a sectional view of a hydraulic pipe expanding tool according to an embodiment of the second invention before pipe expansion.

FIG. 5 is a sectional view of a hydraulic pipe expanding tool according to an embodiment of the second invention after pipe expansion.

FIG. 6 is an enlarged view of an arrow VI portion in FIG.

FIG. 7 is a sectional view of a conventional hydraulic pipe expanding tool before pipe expansion.

FIG. 8 is a sectional view of a conventional hydraulic pipe expanding tool after pipe expansion.

[Explanation of symbols]

 21, 41 Tube plate 22, 42 Tube hole 23, 43 Heat transfer tube 24, 44 Hydraulic expansion tool (tool) 25, 45 Gap 26, 46 Mandrel 27, 47 Coloring 28 First soft elastic body 29 Second soft elastic body 30,49 Hard elastic body 31,50 Liquid injection hole 33,52 Internal pressure

Claims (2)

[Claims] 1. A mandrel having a diameter-increased portion formed at a tip end thereof, a liquid injection passage formed therein, and a liquid injection passage opened at the center of a shaft portion, and a back surface contacting the diameter-increased portion. Hydraulic pressure having a backup color ring fitted to the shaft portion of the mandrel and an annular first soft elastic body fitted to the shaft portion of the mandrel and facing a liquid space in which the liquid injection passage is opened. In pipe expanding tools,
An annular second soft elastic body that contacts the back surface of the first soft elastic body and an annular hard elastic body that contacts the back surface of the second soft elastic body are provided between the backup collar ring and the first soft elastic body. A hydraulic pipe expanding tool characterized in that it is provided in the. 2. A mandrel having a diameter-increased portion formed at a tip portion thereof, a liquid injection passage formed inside thereof, and a liquid injection passage opened at the center of a shaft portion, and a back surface contacting the diameter-increased portion. A hydraulic pipe expanding tool having a backup collar ring fitted to the shaft portion of the mandrel and an annular soft elastic body fitted to the shaft portion of the mandrel and facing a liquid space in which the liquid injection passage is opened. In the above, a hard elastic body having a taper portion whose diameter is reduced toward the backup color ring and a cylindrical straight portion is provided between the backup color ring and the soft elastic body. Hydraulic pipe expanding tool.