JP2004346990A - Piping apparatus and method for installing piping - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce stress in small diameter piping, etc., which stress is caused by the difference of the thermal deformation in large diameter piping and small diameter piping. <P>SOLUTION: A piping apparatus comprises the large diameter piping 1 which at least partially moves because of thermal deformation caused by temperature change during an installed time and an operating time, the small diameter piping 3 one end of which is connected to the large diameter piping, and a support 7 for preventing a lateral movement of the small diameter piping. The support is arranged so as to shift within the range smaller than the movement of the jointed portion by preliminarily applying a load to the small diameter piping in the direction of the movement of the jointed portion of the small diameter piping and the large diameter piping due to the thermal deformation. The large diameter piping and the small diameter piping are used, for example, as the piping in a nuclear power plant. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a piping system and a piping installation method, and more particularly to a piping system with thermal expansion or thermal contraction and a method of installing the same.
[0002]
[Prior art]
2. Description of the Related Art In various plants, a large-diameter pipe through which a high-temperature fluid or a low-temperature fluid flows is connected to a smaller-diameter measurement pipe or the like. In this case, if there is a temperature difference between the large-diameter pipe and the small-diameter pipe, a difference occurs in thermal expansion or thermal contraction (hereinafter, these are collectively referred to as thermal deformation). In a typical plant, in such a case, a design is often made such that a special bent portion is provided in the small-diameter pipe to allow a bending deformation of the small-diameter pipe to absorb a difference in thermal deformation. .
[0003]
[Problems to be solved by the invention]
However, for example, in a nuclear power plant, a rigid design is adopted in which a plurality of supports are installed at relatively short intervals in the axial direction of the small-diameter pipe in order to prevent deflection of the small-diameter pipe due to an earthquake or the like. For this reason, a relatively large load is applied to the small-diameter pipe and the small-diameter pipe support member due to a difference in thermal deformation between the large-diameter pipe (for example, main steam pipe) and the small-diameter pipe. Sometimes it was difficult to do so.
[0004]
Accordingly, the present invention provides a piping facility and a piping installation method that reduce the load applied to a small-diameter pipe and a small-diameter pipe support member due to a difference in thermal deformation between a large-diameter pipe and a small-diameter pipe, thereby reducing stress generated in the pipe. The purpose is to provide.
[0005]
[Means for Solving the Problems]
The present invention has been made in accordance with the above object, and an invention according to claim 1 is a large-diameter pipe that moves at least partially due to thermal deformation accompanying a temperature change between installation and operation, and a large-diameter pipe. A pipe having a smaller diameter than the pipe and having one end connected to the large diameter pipe, and a support for restraining the lateral movement of the small diameter pipe at at least one position of the small diameter pipe. In the equipment, the support applies a load to the small-diameter pipe in advance in the direction of movement due to the thermal deformation of the connection section between the small-diameter pipe and the large-diameter pipe, and is smaller than the movement amount of the connection section. It is characterized by being displaced within a range.
[0006]
According to a second aspect of the present invention, in the piping facility according to the first aspect, the large-diameter pipe and the small-diameter pipe are pipes in a nuclear power plant.
[0007]
According to a third aspect of the present invention, in the plumbing equipment according to the first or second aspect, a displacement amount of the support is substantially half of a movement amount of the connection part during the operation. I do.
[0008]
Further, the invention according to claim 4 connects a small-diameter pipe smaller in diameter than the large-diameter pipe to a large-diameter pipe that moves at least partially due to thermal deformation caused by a temperature change between the time of installation and the time of operation. In the pipe installation method for installing the small-diameter pipe, the large-diameter pipe installation step of installing the large-diameter pipe, and after the large-diameter pipe installation step, connect the large-diameter pipe and the small-diameter pipe. After the small-diameter pipe installation step of installing the small-diameter pipe, and after the small-diameter pipe installation step, a load is applied to the small-diameter pipe, and the small-diameter pipe is partially displaced, A support installation step of installing a support for restraining the lateral movement of the small-diameter pipe in at least one place of the pipe, wherein the installation position of the support is a connection between the small-diameter pipe and the large-diameter pipe. Part of the heat In the direction of movement by the form that is previously displaced position range smaller than the movement amount of the connecting portion, and wherein.
[0009]
According to a fifth aspect of the present invention, in the piping installation method according to the fourth aspect, a display unit that displays a target position of the small-diameter pipe in each of the small-diameter pipe installation step and the support installation step. And a display section installation step of previously installing the display section.
[0010]
The invention according to claim 6 is the piping installation method according to claim 4 or 5, wherein the large-diameter pipe and the small-diameter pipe are pipes in a nuclear power plant.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
As an embodiment of the present invention, as shown in FIG. 1, a case will be described in which, for example, a small-diameter pipe 3 for instrumentation is connected to an existing large-diameter pipe 1 such as a main steam pipe of a nuclear power plant. . The large-diameter pipe 1 moves due to thermal expansion between a plant operation under a high-temperature environment and an installation construction environment at normal temperature. That is, in FIG. 1, the connection portion 5 between the large-diameter pipe 1 and the small-diameter pipe 3 is located at the position indicated by the reference numeral 5 at normal temperature, but is up to the position indicated by the reference numeral 5a during the plant operation by the distance s (in FIG. )Moving. On the other hand, even when the plant is in operation, the small-diameter piping 3 for instrumentation does not become very hot except for a portion near the connection portion 5 between the large-diameter piping 1 and the small-diameter piping 3 and has little thermal expansion.
[0012]
In the installation work of the small-diameter pipe 3, first, the small-diameter pipe 3 is arranged, and the large-diameter pipe 1 and the small-diameter pipe 3 are connected by the connecting portion 5. At this time, the small diameter pipe support 7 is not fixed yet. The horizontal position of the pipe corresponding to the pipe direction position corresponding to the position of the support 7 at this time (temporary installation) is a position indicated by reference numeral 7c as shown in FIG.
[0013]
In the example shown in FIG. 1, the small-diameter pipe 3 is two-dimensionally bent substantially at a right angle in two places, but the number and shape of the bent portion are arbitrary in the present invention. The support 7 restricts the movement of the small-diameter pipe 3 in the lateral direction (the direction perpendicular to the pipe direction), for example, and does not restrict the movement in the pipe direction.
[0014]
Next, a load is applied to the small-diameter pipe 3 to cause elastic deformation as shown by a dashed line 3a, and the support 7 is fixed in that state. At this time, the direction of movement of the support 7 from the position 7c of the support when no load is applied is the same as the direction of movement from the position of reference numeral 5 to the position of reference numeral 5a of the connection part during plant operation (upward in FIG. 1). ), And the moving amount t of the support 7 is preferably set to be about half of the moving distance s of the connecting portion 5.
[0015]
In the piping equipment installed as described above, the connection part 5 moves to the position indicated by the reference numeral 5a due to thermal expansion of the large-diameter pipe 1 during plant operation. At this time, the small diameter pipe 3 is restrained by the connecting portion 5a and the support 7, and elastically deforms as shown by a broken line 3b. In this state, the connecting portion 5 of the small-diameter pipe 3 has moved upward by the distance s as compared to the free state before the support 7 is fixed, while the position of the support 7 has moved upward by the distance t compared to the free state. I'm moving. Therefore, the amount of elastic deformation at both ends of the small-diameter pipe 3 is (s−t).
[0016]
According to this embodiment, both ends of the small-diameter pipe 3 are different from a conventional method in which a load is not applied when the support 7 is installed (corresponding to setting t = 0 in the description of the above embodiment). The amount of elastic deformation at is reduced by t. However, in this embodiment, since the load is applied during the installation work of the small-diameter pipe 3 (at normal temperature), the design is to minimize the stress on the pipe when the normal temperature and the high temperature are considered together. It is desirable to do. In that sense, it is appropriate that the distance t is about half of the distance s. In this embodiment, the loads on the small-diameter pipe 3 at normal temperature and high temperature are opposite to each other, and the resulting stresses are also opposite to each other.
[0017]
Next, with reference to FIG. 1 and FIG. 2, a description will be given of a display plate 10 used when installing piping in the present embodiment. The display plate 10 is fixed at the position of the support 7 before installing the small-diameter pipe 3. As shown in FIG. 2, two target positions of the small-diameter pipe 3 arranged on the display plate 10 are displayed on the display plate 10. That is, one is a provisional installation line 12 which is displayed at a position where the small-diameter pipe 3 before fixing the support should be provisionally installed first, and the other is a small-diameter line when the support is finally fixed. This is a fixed line 14 indicating the position of the pipe 3a.
[0018]
When such a display plate 10 is fixed in advance, the small-diameter pipe 3a is aligned with the temporary installation line 12 during temporary installation, and the small-diameter pipe 3a is fixed when the support 7 is fixed. Since it suffices to make the value coincide with 14, the workability is good.
[0019]
As described above, the main steam pipe of the nuclear power plant has been described as an example, but the present invention is not limited to this, and can be widely applied to pipes involving thermal expansion and contraction. Further, the support is not limited to one place, but may be plural places. In addition, although the small-diameter pipe is arranged two-dimensionally and deformed in the same plane as an example, the pipe may be accompanied by three-dimensional deformation.
[0020]
【The invention's effect】
As described above, according to the present invention, it is possible to reduce the load applied to the small-diameter pipe and the small-diameter pipe support member due to the difference in thermal deformation between the large-diameter pipe and the small-diameter pipe, and thereby, the pipe and the like can be reduced. Can be alleviated.
[Brief description of the drawings]
FIG. 1 is a schematic plan view of an embodiment of a piping facility according to the present invention.
FIG. 2 is an enlarged plan view showing an example of display contents of a display panel in FIG.
[Explanation of symbols]
1 large-diameter piping, 3 small-diameter piping (normal temperature, temporary installation), 3a small-diameter piping (normal temperature, fixed support), 3b small-diameter piping (high temperature), 3c small-diameter piping (conventional technology) , High temperature), 5 ... connection part (at normal temperature), 5a ... connection part (at high temperature), 7 ... support, 7c ... support (prior art), 10 ... display board, 12 ... temporary installation wire, 14 ... fixed wire .

Claims (6)

A large-diameter pipe that moves at least partially due to thermal deformation due to a temperature change between installation and operation, and a small-diameter pipe that has a smaller diameter than the large-diameter pipe and one end is connected to the large-diameter pipe. A support that restrains lateral movement of the small-diameter pipe at at least one location of the small-diameter pipe,
The support applies a load to the small-diameter pipe in advance in a direction of movement due to the thermal deformation of the connection section between the small-diameter pipe and the large-diameter pipe, and is displaced within a range smaller than the movement amount of the connection section. That they are located
Piping equipment. The piping facility according to claim 1, wherein the large-diameter pipe and the small-diameter pipe are pipes in a nuclear power plant. 3. The piping facility according to claim 1, wherein an amount of displacement of the support is substantially half of a moving amount of the connecting part during the operation. 4. A pipe installation that connects a small-diameter pipe smaller in diameter than this large-diameter pipe to a large-diameter pipe that moves at least partially due to thermal deformation due to temperature changes between installation and operation, and installs this small-diameter pipe In the method,
A large-diameter pipe installation step of installing the large-diameter pipe,
After the large-diameter pipe installation step, connecting the large-diameter pipe and the small-diameter pipe, a small-diameter pipe installation step of installing the small-diameter pipe,
After the step of installing the small-diameter pipe, in a state where the small-diameter pipe is partially displaced by applying a load to the small-diameter pipe, the lateral movement of the small-diameter pipe is performed at least at one position of the small-diameter pipe. A support installation process of installing a support that restrains the
Has,
The installation position of the support is a position displaced in advance in a direction smaller than the amount of movement of the connection portion in the direction of movement due to the thermal deformation of the connection portion between the small-diameter pipe and the large-diameter pipe,
A piping installation method characterized by the above-mentioned. The pipe installation method according to claim 4, further comprising a display section installation step of previously installing a display section for displaying a position of the target small diameter pipe in the small diameter pipe installation step and the support installation step. A piping installation method characterized by the above-mentioned. 6. The piping installation method according to claim 4, wherein the large-diameter piping and the small-diameter piping are piping in a nuclear power plant.

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