JP7406603B2 - curved pipe - Google Patents

Description

The present invention relates to a curved pipe.

Bent pipes used for water pipes and the like have been made using various methods. For example, Patent Document 1 discloses a method of forming a curved pipe by connecting straight pipe members whose ends are cut diagonally. In this curved pipe, an FRP material is wrapped around and fixed at the joint between adjacent pipe members.

Japanese Patent Application Publication No. 2015-40867

However, in the above-mentioned bent pipe, in order to improve the connection strength of the FRP material, many layers of FRP materials are stacked in the axial direction. However, in such a laminated state, there is a problem that the outer circumferential surface has large irregularities and looks unsightly. The present invention was made in order to solve the above problems, and aims to provide a curved pipe that can suppress reduction in connection strength due to FRP materials and improve appearance.

The curved pipe according to the present invention includes a plurality of pipe members connected in the axial direction, the plurality of pipe members connected in an arc shape as a whole so that the axes of the adjacent pipe members intersect with each other, A plurality of inner FRP materials formed in a sheet shape are fixed so as to cover the joints of the adjacent pipe members on the inner peripheral surface of the pipe members, and the joints of the adjacent pipe members are fixed to cover the joints of the pipe members on the outer circumference of the pipe members. A plurality of first outer FRP materials fixed so as to cover the surfaces thereof and formed in a sheet shape, and a plurality of first outer FRP materials fixed so as to cover the plurality of first outer FRP materials on the outer peripheral surfaces of the plurality of tube members and formed in a sheet shape. at least one second outer FRP material formed in;
It is equipped with

In each of the curved pipes, each of the first outer FRP materials can be fixed so as to cover one of the joints.

In each of the curved pipes, one of the second outer FRP materials can be fixed so as to cover all of the first outer FRP materials.

In each of the curved pipes, each of the inner FRP materials can be fixed so as to cover one of the joints.

According to the bent pipe according to the present invention, reduction in connection strength due to the FRP material can be suppressed, and the appearance can be improved.

FIG. 1 is a side view of a curved pipe according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of FIG. 1; FIG. 3 is a sectional view showing another example of a curved pipe according to the present invention. FIG. 3 is a sectional view showing another example of a curved pipe according to the present invention.

Hereinafter, one embodiment of a curved pipe according to the present invention will be described with reference to the drawings. This curved pipe can be used for various purposes, such as water and sewage pipes, agricultural water pipes, and industrial water pipes.

<1. Overview of curved pipes>
FIG. 1 is a side view of the curved pipe according to this embodiment, and FIG. 2 is a cross-sectional view of FIG. 1. As shown in FIGS. 1 and 2, this bent pipe includes a plurality of pipe members 11 to 14, a plurality of inner FRP materials 21 to 23 fixed to the inner peripheral surfaces of the pipe members 11 to 14, and A plurality of first outer FRP materials 31 to 33 fixed to the outer peripheral surfaces of the tube members 11 to 14, and a plurality of first outer FRP materials 31 to 33 fixed to the outer peripheral surfaces of the tube members 11 to 14 so as to cover the plurality of first outer FRP materials 31 to 33. A second outer FRP material 4 is provided. Each member will be explained in detail below.

<1-1. Pipe members>
In this embodiment, a curved pipe in which four pipe members are connected is shown as an example, but for convenience of explanation, the pipe members arranged from the left side to the right side in FIGS. 1 and 2 are arranged in this order into the first pipe. They will be referred to as a member 11, a second pipe member 12, a third pipe member 13, and a fourth pipe member 14. Each of the tube members 11 to 14 is formed into a cylindrical shape with the same diameter, and the opening surfaces at both ends intersect with each other and with the axes X1 to X4, respectively. By abutting the open end surfaces of the plurality of tube members 11 to 14 formed in this manner, the tube members 11 to 14 are connected so as to form an arc shape as a whole.

In this embodiment, four pipe members 11 to 14 are connected as an example, but the number of pipe members to be connected, the angle of the opening end surface with respect to the axis, etc. can be set as appropriate. However, for example, according to the water gate iron pipe technical standards, the swing angle θ (see Fig. 1) of each pipe member 11 to 14 is 7 degrees or less, and the radius of curvature R of the axis of the entire curved pipe (see Fig. 2) is It is necessary to make it three times or more the inner diameter D of.

The nominal diameter of the tube members 11 to 14 can be, for example, 500 to 2600 mm. Further, the thickness of the pipe members 11 to 14 is not particularly limited as it varies depending on the nominal diameter, but can be, for example, 5 to 60 mm, or 0.2 to 12% of the nominal diameter. .

Each of the tube members 11 to 14 can be constructed of a hard resin tube such as a known fiber reinforced plastic tube (FRP tube) or fiber reinforced plastic composite tube (FRPM tube). FRP tubes and FRPM tubes can be manufactured, for example, by a filament winding molding method.

<1-2. Inside FRP material＞
Each of the inner FRP materials 21 to 23 is formed into a sheet shape, and is arranged so as to cover the joints 101 to 103 of the butted tube members 11 to 14 from the inner peripheral surface side. In this embodiment, since four pipe members 11 to 14 are used, three seams 101 to 103 are formed. Therefore, three inner FRP materials 21 to 23 are prepared so as to circumferentially cover these three seams 101 to 103, respectively. Each of the inner FRP materials 21 to 23 is arranged so as to cover the seams 101 to 103 in one layer, but the ends of each of the inner FRP materials 21 to 23 may overlap, forming a part of the two layers. . Note that, depending on the required withstand pressure (internal pressure), the inner FRP materials 21 to 23 may be laminated to have two or more layers as a whole. However, if the layer is multi-layered, it may impede the flow of liquid within the curved pipe, so it is necessary to make it as thin as possible. Further, it is preferable to adjust the width in the axial direction so that the inner FRP materials 21 to 23 that are adjacent to each other in the axial direction do not overlap each other.

Each of the inner FRP materials 21 to 23 is made of fiber reinforced plastic (FRP). That is, it is composed of reinforcing fibers and a matrix resin impregnated into the reinforcing fibers. The reinforcing fibers are not particularly limited, and for example, inorganic fibers such as glass fibers and carbon fibers, or organic fibers such as aramid fibers and polyethylene terephthalate fibers can be used. These fibers can be used alone or in combination. Further, as the reinforcing fibers, in addition to woven fabrics such as roving cloth, non-woven fabrics such as glass mats can be used.

Furthermore, as the matrix resin, for example, thermosetting resins such as unsaturated polyester resins, epoxy resins, and vinyl ester resins are preferably used. However, thermoplastic resins are not specifically excluded. Examples include urethane, vinyl ester, unsaturated polyester, polyamide, epoxy resin, polycarbonate, nylon, polyethylene, polyethylene terephthalate, polyphenylene sulfide, and poly(meth)acrylic acid ester. These resins can be used alone or in combination. Further, a known curing agent or curing accelerator can be added as necessary.

The thickness of the inner FRP materials 21 to 23 is not particularly limited, but may be, for example, 0.02 to 0.2 mm.

<1-3. First outer FRP material>
Each of the first outer FRP materials 31 to 33 is formed into a sheet shape, and is wound so as to cover the joints 101 to 103 of the butted tube members 11 to 14 along the circumferential direction from the outer peripheral surface side. That is, they are arranged to face each of the above-mentioned inner FRP materials 21 to 23 with the tube members 11 to 14 in between. In this embodiment, like the inner FRP materials 21 to 23, three first outer FRP materials 31 to 33 are used, and the axial The width of the direction has been adjusted. Other specific configurations, including material and thickness, are generally the same as those of the inner FRP materials 21 to 23, so detailed explanations will be omitted.

<1-4. Second outer FRP material>
The second outer FRP material 4 is formed into a sheet shape and is fixed so as to cover the outer peripheral surfaces of the tube members 11 to 14. Specifically, it is wrapped around the outer peripheral surfaces of the tube members 11 to 14 so as to cover all of the three first outer FRP materials 31 to 33 described above. That is, the second outer FRP material 4 extends in the axial direction from near the middle of the first pipe member 11 to near the middle of the fourth pipe member 14. Other specific configurations, including material and thickness, are generally the same as those of the inner FRP materials 21 to 23, so detailed explanations will be omitted.

<2. Manufacturing method of bent pipe>
Next, a method for manufacturing the curved pipe formed as described above will be described. First, four tube members 11 to 14 are prepared as described above. The method for preparing the tube members 11 to 14 is not particularly limited, but for example, the plurality of tube members 11 to 14 having sloped end surfaces as described above are prepared by cutting a cylindrical straight tube.

Next, the end surfaces of the four prepared tube members 11 to 14 are brought together and connected so that the axes X1 to X4 extend in an arc shape. Then, the pipe members 11 to 14 are fixed with a jig or the like so as to maintain this connected state. Further, if necessary, the joints 101 to 103 of the adjacent pipe members 11 to 14 are polished to remove burrs and the like so that the joints are flat.

Subsequently, the inner FRP materials 21 to 23 are arranged on the inner circumferential surfaces of the tube members 11 to 14 along each of the three seams 101 to 103 so as to cover each of the seams 101 to 103 in the circumferential direction. At this time, each of the inner FRP materials 21 to 23 disposed at the seams 101 to 103 is formed into one layer so that only the ends in the circumferential direction overlap. The method for arranging each of the inner FRP materials 21 to 23 is not particularly limited, but for example, a hand lay-up method can be adopted. That is, after the reinforcing fibers are arranged along the seams 101 to 103, the reinforcing fibers are impregnated with the matrix resin. At this time, a curing agent is added to the thermosetting resin. As a result, after curing for a predetermined period of time, the inner FRP materials 21 to 23 arranged at the seams 101 to 103 harden.

Subsequently, the first outer FRP materials 31 to 33 are applied on the outer peripheral surfaces of the pipe members 11 to 14 along each of the three seams 101 to 103 so as to cover each of the seams 101 to 103 in the circumferential direction. Deploy. At this time, each of the first outer FRP materials 31 to 33 disposed at the seams 101 to 103 is formed into one layer so that only the ends in the circumferential direction overlap. Each of the first outer FRP materials 31 to 33 can also be placed at the seams 101 to 103 by, for example, a hand layup method. Then, like the inner FRP materials 21 to 23, if a hardening agent is added to the matrix resin, each of the outer FRP materials 31 to 33 disposed at the seams 101 to 103 will harden after curing for a predetermined time.

Finally, the second outer FRP material 4 is arranged so as to cover all of the three first outer FRP materials 31 to 33 on the outer peripheral surfaces of the connected pipe members 11 to 14. The second outer FRP material 4 has one layer so that only the ends in the circumferential direction overlap. The second outer FRP material 4 can also be arranged by, for example, a hand layup method. Then, like the inner FRP materials 21 to 23, if a hardening agent is added to the matrix resin, the second outer FRP material 4 will harden on the first outer FRP materials 31 to 33 after curing for a predetermined time. In this way, the bent pipe according to this embodiment is completed.

Note that for the arrangement of the FRP material, in addition to the hand lay-up method, for example, a filament winding method can also be adopted. Further, the matrix resin can also be cured in a heating furnace.

<3. Features>
In the curved pipe configured as described above, the FRP materials 31 to 33, 4 arranged on the outer circumferential surface have two layers at most. That is, the maximum number of stacked FRP materials is 2 (the part where both the first outer FRP materials 31 to 33 and the second outer FRP material 4 are stacked), and the minimum number of stacked layers is 1 (the part where both the first outer FRP materials 31 to 33 and the second outer FRP material 4 are stacked). (The part where only the outer FRP material 4 is laminated). Therefore, since the difference between the laminated layers of the FRP material is 1, it is possible to reduce the unevenness formed on the outer circumferential surface of the curved pipe. As a result, the appearance of the curved pipe can be improved, and large differences in stress distribution can be prevented. Furthermore, since at least two layers of FRP materials 31 to 33 and 4 are laminated at the joints 101 to 103 on the outer circumferential surface of the curved pipe, it is possible to prevent the connection strength from decreasing.

On the other hand, since one layer of inner FRP materials 21 to 23 is laminated on the inner circumferential surface of the curved pipe, the unevenness is small and it is possible to spin the material without obstructing the flow of fluid.

<4. Modified example>
Although one embodiment of the present invention has been described above, the present invention is not limited to this, and various changes can be made without departing from the spirit thereof. Note that the following modifications can be combined as appropriate.

<4-1>
In the above embodiment, each of the first outer FRP materials 31 to 33 is arranged to cover one seam 101 to 103. For example, as shown in FIG. , can also be arranged across multiple seams (for example, seams 101, 102). This point is also the same for the inner FRP materials 21 to 23.

<4-2>
In the above embodiment, one second outer FRP material 4 covers all the first outer FRP materials 31 to 33, but if the length in the axial direction to be covered is long, for example, as shown in FIG. As such, the plurality of second outer FRP materials 41 and 42 can also be arranged so as to be lined up in the axial direction. In this example, a second outer FRP material 41 covering two first outer FRP materials 31 and 32 and a second outer FRP material 42 covering one first outer FRP material 33 are used. At this time, it is necessary to prevent the adjacent second outer FRP materials 41 and 42 from overlapping as much as possible, or to adjust the width in the axial direction so that even if they overlap, it is slight. .

<4-3>
In the above embodiment, the inner FRP materials 21 to 23, the first outer FRP materials 31 to 33, and the second outer FRP 4 are all made of one layer, but they can be made of two or more layers if necessary. However, the FRP materials are arranged such that one first outer FRP material 31 to 33 overlaps with the second outer FRP material 4, and adjacent first outer FRP materials 31 to 33 do not overlap with each other. Thereby, unevenness can be made as small as possible.

<4-4>
In the above embodiment, only the inner FRP materials 21 to 23 are arranged on the inner peripheral surfaces of the tube members 11 to 14, but like the second outer FRP material 4 on the outer peripheral surface, these inner FRP materials 21 to 23 It is also possible to further provide an FRP material covering the.

11-14 Pipe members 21-23 Inner FRP material 31-33 First outer FRP material 4 Second outer FRP material

Claims (4)

It is a curved pipe,
a plurality of tube members connected in the axial direction, the plurality of tube members connected in an arc shape as a whole such that the axes of the adjacent tube members intersect with each other;
a plurality of inner FRP materials formed in a sheet shape and arranged so as to cover the joints of the adjacent pipe members on the inner circumferential surface of the pipe members;
a plurality of first outer FRP materials formed in a sheet shape and arranged so as to cover the joints of the adjacent pipe members on the outer circumferential surface of the pipe members;
At least one second outer FRP material formed in a sheet shape and arranged on the plurality of first outer FRP materials on the outer peripheral surface of the plurality of tube members;
Equipped with
One layer of the inner FRP material is arranged for each seam,
The thickness of the inner FRP material is 0.02 to 0.2 mm,
The second outer FRP material is not provided over the entire axial direction of the curved pipe, and the pipe member is exposed at least at the end of the curved pipe in the axial direction,
The pipe member whose axial ends are connected to the other pipe member is a curved pipe whose entire outer peripheral surface is covered with at least one of the first outer FRP material and the second outer FRP material. The curved pipe according to claim 1, wherein at least one of the plurality of first outer FRP materials is configured to cover the plurality of joints. It is a curved pipe,
a plurality of tube members connected in the axial direction, the plurality of tube members connected in an arc shape as a whole such that the axes of the adjacent tube members intersect with each other;
a plurality of inner FRP materials formed in a sheet shape and arranged so as to cover the joints of the adjacent pipe members on the inner circumferential surface of the pipe members;
a plurality of first outer FRP materials formed in a sheet shape and arranged so as to cover the joints of the adjacent pipe members on the outer circumferential surface of the pipe members;
At least one second outer FRP material formed in a sheet shape and arranged on the first outer FRP material on the outer peripheral surface of the plurality of tube members;
Equipped with
One layer of the inner FRP material is arranged for each seam,
The thickness of the inner FRP material is 0.02 to 0.2 mm,
At least one of the plurality of first outer FRP materials is configured to cover the plurality of seams,
The second outer FRP material is not provided over the entire axial direction of the curved pipe, and the pipe member is exposed at least at the end of the curved pipe in the axial direction,
The pipe member whose axial ends are connected to the other pipe member is a curved pipe whose entire outer peripheral surface is covered with at least one of the first outer FRP material and the second outer FRP material. The curved pipe according to claim 1 or 3, wherein each of the inner FRP materials is fixed so as to cover one of the joints.