CN113167418A

CN113167418A - Loose flange and pipe joint

Info

Publication number: CN113167418A
Application number: CN202080006378.6A
Authority: CN
Inventors: 加藤刚志; 近藤博昭; 高井启司
Original assignee: Sekisui Chemical Co Ltd
Current assignee: Sekisui Chemical Co Ltd
Priority date: 2019-03-29
Filing date: 2020-03-27
Publication date: 2021-07-23
Anticipated expiration: 2040-03-27
Also published as: JPWO2020203846A1; CN113167418B; TWI730698B; JP6908801B2; KR20210058996A; WO2020203846A1; TW202040040A; KR102381672B1

Abstract

The loose flange plate has high mechanical strength and can bear bolt fastening torque. The loose flange (40) is produced by injection molding of a fiber-reinforced resin. A welding part (47) is formed at one or more parts of the annular flange main body (41) of the loose flange (40). A welding position rib (44A) is provided at each part of the flange main body (41) so as to straddle the welding portion (47). The loose flange (40) is rotatably fitted to the outer periphery of the stub (30) and is joined to the flange (24) to be joined.

Description

Loose flange and pipe joint

Technical Field

The present invention relates to a loose flange used for joining pipes to each other and a pipe joint with the loose flange.

Background

Generally, flanges for connecting to other pipes are provided at the ends of various pipes such as factory piping. The flanges of the two pipes are connected to each other by bolts or the like. In this case, although it is necessary to align the bolt holes of the flanges with each other, it is not easy to adjust the angle of the flanges by rotating the entire pipe. Therefore, a loose flange is used as the flange of at least one of the pipes (see patent document 1 and the like). The loose flange can be rotatably loosely fitted around the circumference of the stub (stub end) at the end of the pipe.

Conventional plant piping is often made of metal, and a loose flange is also often made of metal. On the other hand, due to recent advances in resin synthesis technology, plant piping has been replaced from metal pipes to resin pipes of polyvinyl chloride, polyethylene, and the like, with improvements in mechanical strength, durability, chemical resistance, shock resistance, and the like of resins. Accordingly, a resin loose flange is desired.

Patent document 2 discloses joining a short fiber-reinforced resin pipe to be flanged to an end of a fiber-reinforced resin pipe.

Documents of the prior art

Patent document

Patent document 1 Japanese patent application laid-open No. 5-280674

Patent document 2 Japanese patent laid-open No. 2001-205707

Disclosure of Invention

Problems to be solved by the invention

When the inventors developed a resin loose flange, only when the resin loose flange is molded with a general resin such as polyvinyl chloride, for example, the vicinity of the bolt hole of the resin loose flange is easily broken by the fastening torque of the bolt. Therefore, when injection molding is tried using Glass Fiber Reinforced Plastic (GFRP), a new problem arises in that the GFRP loose flange is likely to be broken at the welded portion (weld) when a bolt fastening torque is applied. This is considered to be because the orientation of the reinforcing fibers in the welded portion is oriented in a direction orthogonal to the flow direction of the resin during injection molding.

The present invention is based on this finding and examination, and an object thereof is to provide a loose flange made of fiber-reinforced resin having high mechanical strength and capable of withstanding bolt tightening torque.

Means for solving the problems

In order to solve the above-described problems, the present invention provides a loose flange which is rotatably fitted to an outer periphery of a stub to be joined to a flange to be joined, and which is made of a fiber-reinforced resin, the loose flange comprising:

an annular flange main body;

a welding part formed at one portion or a plurality of portions separated in a circumferential direction of the flange main body; and

and a welding position rib (protection rib) provided at each of the portions of the flange main body so as to straddle the welding portion.

The rigidity of the loose flange is improved by making the loose flange be made of fiber reinforced resin.

The loose flange is preferably manufactured by injection moulding. That is, a melt of the raw material resin mixed with the reinforcing fibers is supplied from the gate to the annular cavity for forming the loose flange. The melt flows from the gate in two directions in the circumferential direction of the annular chamber. At a predetermined position apart from the gate in the circumferential direction, the melts in the two directions merge with each other to form a welded portion.

The reinforcing fibers are oriented in a substantially circumferential direction along the flow of the melt at the non-welded portion away from the welded portion. Oriented in a direction intersecting the circumferential direction in the welded portion.

By providing the welding position rib so as to straddle the welding portion, stress is dispersed, and stress concentration in the welding portion is relaxed. This improves the mechanical strength of the loose flange made of fiber-reinforced resin, and prevents the fracture of the welded portion due to the bolt tightening torque, the pipe internal pressure, the thermal stress, and the like.

Preferably, the welding position rib protrudes from a back surface of the flange main body facing a side opposite to the flange to be joined.

This can prevent the welding position rib from becoming an obstacle to the joining. The front surface of the loose flange facing the flange to be joined can be made flat.

Preferably, the weld site rib extends in a radial direction of the flange main body.

This enables the welding position rib to be along the welded portion.

Preferably, the welding position rib reaches an inner peripheral surface and an outer peripheral surface of the flange main body.

This enables the welding position rib to cover the entire region in the extending direction of the welded portion.

Preferably, a pair of inner corner portions are formed on both side end surfaces of the welding position rib in the width direction and on the back surface of the flange main body as viewed in the radial direction of the flange main body, and the welding portion is disposed so as to be sandwiched between these inner corner portions.

As a result, stress concentration is also generated in the inner corner portions by bolt fastening or the like. In other words, the stress to be concentrated on the welded portion is dispersed toward the nearest inner corner portions on both sides thereof. This can reliably prevent the welded portion from cracking.

The width of the welding position rib along the circumferential direction is preferably 10mm to 20mm, more preferably 13mm to 16 mm.

This makes it possible to reliably exhibit the effect of dispersing stress from the welded portion by the welding position rib and the effect of suppressing stress concentration at the welded portion. If the width of the rib at the welding position is too narrow, the effect of suppressing stress concentration at the welding portion is reduced. If the width is too wide, the stress concentration suppressing effect is lowered and the material cost is increased.

The projection height of the welding position rib from the flange main body in the axial direction is preferably 2mm to 10mm, and more preferably 4mm to 6 mm.

If the projection height of the rib at the welding position is too small, the effect of suppressing the stress concentration at the welded portion is not so obtained. If the protrusion height is too large, the stress concentration suppression effect is lowered and the material cost is increased.

Preferably, the flange main body has a plurality of ribs formed so as to be circumferentially spaced apart from each other, and at least a part of the ribs is disposed on the welded portion to constitute the welding position rib.

The position of the welded portion is determined according to the position of the injection-molded gate. Therefore, it is preferable to set the arrangement of the welding position rib according to the position of the gate.

The ribs are more preferably arranged at equal intervals in the circumferential direction.

Preferably, the flange main body has bolt holes formed in a rib circumferentially apart from the welding positions.

The welding position rib is preferably disposed in an intermediate portion between two adjacent bolt holes.

Preferably, the present invention provides a loose flange which is rotatably fitted to an outer periphery of a stub to be joined to a flange to be joined, and which is made of a fiber-reinforced resin, the loose flange including:

an annular flange main body; and

a welding position rib provided at one portion or a plurality of portions separated in a circumferential direction of the flange main body,

the reinforcing fibers of the fiber-reinforced resin in the flange main body are oriented substantially in a direction intersecting the circumferential direction at the location where the rib is disposed at the welding position, and are oriented substantially in the circumferential direction at a location away from the rib at the welding position in the circumferential direction.

By providing the welding position rib in the welded portion, it is possible to avoid a decrease in mechanical strength even if the orientation of the reinforcing fibers changes in addition to the welded portion.

Further, the present invention provides a pipe joint provided at an end portion of one pipe and joined to a joining target, the pipe joint including:

a stub including a tubular pipe insertion portion into which the pipe end portion is inserted, and an annular flare portion provided to project from an end portion of the pipe insertion portion on a joining target side toward an outer circumferential side; and

a loose flange plate made of fiber reinforced resin and rotatably fitted to the outer periphery of the stub,

the loose flange plate is provided with:

an annular flange main body;

and a welding position rib provided at each of the portions of the flange main body so as to straddle the welding portion.

Effects of the invention

According to the present invention, a fiber-reinforced resin loose flange having high mechanical strength and capable of withstanding bolt tightening torque can be provided.

Drawings

Fig. 1 is a side sectional view of a pipe joint structure according to a first embodiment of the present invention.

Fig. 2 is an exploded side sectional view of the pipe joint structure.

Fig. 3(a) is a top view of the stub of one of the pipe joint constructions. Fig. 3(b) is a side view of the stub.

Fig. 4 is a sectional view showing a part of the pipe joint in an enlarged manner.

Fig. 5 is a front view of the loose flange of the coupling.

Fig. 6(a) is a rear view showing a first mode of the loose flange.

Fig. 6(b) is a rear view showing a second mode of the loose flange.

Fig. 6(c) is a rear view showing a third mode of the loose flange.

Fig. 7(a) is a sectional view taken along line VIIa-VIIa in fig. 6 (b). Fig. 7(b) is a sectional view taken along line VIIb-VIIb of fig. 6 (b).

Fig. 8 is a sectional view taken along line VIII-VIII of fig. 6 (a).

Fig. 9 is a cross-sectional view of a loose flange of a second embodiment of the present invention.

Fig. 10 is a graph showing the analysis result of example 2 and showing the relationship between the width dimension of the rib at the welding position and the stress acting on the welded portion.

Fig. 11 is a graph showing the analysis result of example 2 and showing the relationship between the height dimension of the rib at the welding position and the stress acting on the welded portion.

Fig. 12 is an explanatory view showing the result of flow analysis of a fiber-reinforced resin melt at the time of injection molding of a loose flange.

Fig. 13 is an enlarged view of a portion of fig. 12.

Detailed Description

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

< first embodiment >

Fig. 1 shows a joint structure between one pipe 10 and a target pipe 20 in a plant pipe. The material of the

pipes

10 and 20 is, for example, polyvinyl chloride (PVC), polyolefin (polyethylene, polypropylene, etc.), and other resins, and PVC is preferable from the viewpoint of strength, durability, chemical resistance, etc. The two

pipes

10 and 20 are arranged in a line on the pipe axis L and joined by the pipe joint structure 1.

The pipe joint structure 1 includes pipe joints 13 and 23, a bolt 60, a nut 61, and a seal 50. Pipe joints 13 and 23 are provided at opposite ends 12 and 22 of the

pipes

10 and 20. The

flanges

40 and 24 of the pipe joints 13 and 23 are connected to each other with a fastening tool including a bolt 60 and a nut 61 while being in contact with each other with a seal 50 interposed therebetween.

As shown in fig. 2, the pipe joint 13 provided to one pipe 10 includes a cylindrical stub 30 and an annular loose flange 40.

The material of the butt 30 is, for example, polyvinyl chloride (PVC), polyolefin (polyethylene (PE), polypropylene (PP), or the like), or other resin, and is preferably the same material as the pipe 10 in consideration of adhesion to the pipe 10, or the like. When the pipe 10 is made of PVC, the material of the stub 30 is preferably PVC.

As shown in fig. 3(a) and (b) of the drawing, the stub 30 integrally has a tube insertion portion 31 and a flare portion 32. As shown in fig. 2, the tube insertion portion 31 is formed in a cylindrical shape having an insertion hole 33. The insertion hole 33 is tapered so as to be reduced in diameter toward the front (the side facing the joining target). A retaining projection 35 is formed on the outer peripheral surface of the pipe insertion portion 31. A horn 32 is provided at the tip end (end on the joining target side) of the tube insertion portion 31. The horn 32 is formed in a thick ring shape and protrudes outward from the pipe insertion portion 31.

As shown in fig. 1, the pipe end 12 is inserted into the insertion hole 33. The pipe insertion portion 31 and the pipe end portion 12 are bonded together with an adhesive for resin (not shown).

As shown in fig. 2, a loose flange 40 is provided on the outer periphery of the stub 30. The loose flange 40 is loosely fitted to the stub 30 in such a manner as to be rotatable relative to the stub 30.

The loose flange 40 is made of a fiber-reinforced resin including resin and reinforcing fibers. Examples of the resin constituting the loose flange 40 include polyvinyl chloride (PVC), polyolefin (polyethylene (PE), polypropylene (PP), and the like), and other thermoplastic resins, with polyolefin such as PE, PP, and the like being preferred, and polypropylene (PP) being more preferred.

Examples of the reinforcing fiber of the loose flange 40 include glass fiber and carbon fiber. The diameter of the reinforcing fiber is preferably about 10 to 15 μm. The length of the reinforcing fibers is preferably about 200 to 1000. mu.m. The rigidity of the loose flange 40 is improved by the reinforcing fibers.

As shown in fig. 4 to 6(c), the loose flange 40 includes an annular flange main body 41 and a plurality of ribs 44. As shown in fig. 2, the flange body 41 is formed in a circular plate shape having a larger diameter than the flare portion 32. The stub 30 passes through the central hole 41c of the flange body 41. As shown in fig. 5 and 7(a), a relief recess 41g is formed in the inner peripheral surface of the center hole 41c, and the relief recess 41g is configured to pass over the retaining projection 35 when the loose flange 40 is attached to the stub 30.

An annular recess 42 for accommodating the horn 32 is formed in a front portion (portion on the joining target side) of the center hole 41 c.

As shown in fig. 5, a plurality of (for example, 8) bolt holes 43 are formed in the flange body 41. The bolt holes 43 are arranged at intervals, preferably at equal intervals, in the circumferential direction of the loose flange 40. As shown in fig. 4, each bolt hole 43 penetrates in the thickness direction (pipe axis direction) from the front surface 41a of the flange body 41 facing the joining target side to the back surface 41b on the opposite side.

As shown in fig. 1, the loose flange 40 is opposed to the flange 24 of the pipe joint 23 provided at the end of the target pipe 20 (the joining target) via the seal 50, and the bolt holes 43 are aligned with the bolt holes 25 of the flange 24. Bolts 60 are inserted through these bolt holes 43 and 25 and fastened with nuts 61. Thereby, the pipe joints 13, 23 are bolted to each other, and further, the

pipes

10, 20 are joined to each other.

As shown in fig. 6 a to 6 c, a plurality of (for example, four) ribs 44 (including a welding position rib 44A described later) are formed on a back surface 41b (a surface facing a side opposite to the flange 24 to be joined) of the flange main body 41. The ribs 44 are arranged at intervals in the circumferential direction of the loose flange 40. From the viewpoint of weight balance and design of the entire loose flange 40, it is preferable that the ribs 44 be arranged at equal intervals in the circumferential direction of the loose flange 20.

As shown in fig. 7(a), each rib 44 protrudes from the back surface 41b and extends in the radial direction (up and down in fig. 7 (a)) of the loose flange 40. Preferably, both ends of the rib 44 reach the outer circumferential surface and the inner circumferential surface of the loose flange 40.

As shown in fig. 6(a) to 6(c), the rib 44 is disposed apart from the bolt hole 43 in the circumferential direction. That is, the ribs 44 of the loose flange 40 and the bolt holes 43 are arranged at different angles from each other. Two bolt holes 43 are arranged between two ribs 44 separated by 90 °.

As shown in fig. 7(b), a plurality of weight-reducing recesses 45 are also formed in the back surface 41b of the flange body 41 at intervals in the circumferential direction. As shown in fig. 6(a) to 6(c), each weight-reduction recess 45 is disposed between two adjacent bolt holes 43. The arrangement angle of some of the weight-reduction recesses 45 overlaps the arrangement angle of the ribs 44. The overlapped lightening recess 45 is divided into two by the rib 44.

The loose flange 40 is reduced in weight by the weight-reduction recess 45.

In addition, the weight-reduction recess 45 may be omitted.

The loose flange 40 is an injection molded article.

As shown in fig. 6(a) to 6(c), a weld 47 is formed by injection molding at one or a plurality of circumferentially separated locations of the loose flange 40 (flange body 41). The welded portion 47 is a non-flat cross-sectional surface shape substantially orthogonal to the circumferential direction of the loose flange 40.

In the loose flange 40, at least a part of the rib 44 (hereinafter referred to as "welding position rib 44A") is disposed at a formation portion of the welding portion 47. Stated differently, the welded portion 47 of the loose flange 40 is formed to have a thickness greater than the non-welded portion around the welded portion.

As shown in fig. 6(a) to 6(c), the welding position rib 44A (protective rib) spans the corresponding welding portion 47.

As shown in fig. 8, the welded portion 47 enters the welding position rib 44A from the flange body 41 and reaches the projecting end surface 44e of the welding position rib 44A. Preferably, the welded portion 47 in the welding-position rib 44A is disposed at the center in the width direction of the welding-position rib 44A.

As shown in fig. 6(a) to 6(c), the inner peripheral end surface of the welding position rib 44 is flush with the inner peripheral surface of the flange body 41. The inner peripheral end of the welded portion 47 reaches the inner peripheral surfaces of the flange body 41 and the inner peripheral end of the welding position rib 44A.

The outer peripheral end surface of the welding position rib 44 is flush with the outer peripheral surface of the flange body 41. The outer peripheral end of the welded portion 47 reaches the outer peripheral surface of the flange body 41 and the outer peripheral end surface of the welding position rib 44A.

As shown in fig. 7 a, the welding position rib 44A has a constant height in the radial direction (up and down in fig. 7 a) of the loose flange 40. The cross-sectional shape of the welding position rib 44A as viewed from the circumferential direction of the loose flange 40 is a rectangular shape having a relatively large long side and short side.

As shown in fig. 8, the cross-sectional shape of the welding position rib 44A when viewed from the radial direction of the loose flange 40 is a rectangular shape in which the ratio of the long side to the short side is smaller than the ratio when viewed from the circumferential direction.

As shown in fig. 8, a pair of inner corner portions 44g are formed by the side end surfaces 44f on both sides in the width direction of the rib 44A and the back surface 41b of the flange main body 41 at the welding position as viewed in the radial direction of the loose flange 40. The welded portion 47 is disposed between the two inner corner portions 44 g.

Angle theta of inner corner portion 44g_44gPreferably 60 ° to 100 °, more preferably about 90 °.

A pair of outer corner portions 44h are formed by the protruding end surface 44e of the welding position rib 44A and the side end surfaces 44f on both sides. Angle theta of outer corner portion 44h_44hPreferably 60 ° to 100 °, more preferably about 90 °.

As shown in FIG. 8, the width W of the welding position rib 44A₄₄The dimension (in the circumferential direction of the loose flange 40) is preferably 10mm to 20mm, more preferably 13mm to 16 mm. If width W₄₄If it is too small, the inner corner portion 44g comes too close to the welded portion 47, and the effect of dispersing stress from the welded portion 47 is reduced. If width W₄₄If it is too large, the inner corner portion 44g is too far away from the welded portion 47, the stress dispersion effect from the welded portion 47 is reduced, and the material cost is increased.

Height H of projection of welding position rib 44A from back surface 41b of flange body 41₄₄The dimension (in the direction of the tube axis L) is preferably 0.5mm to 30mm, more preferably 2mm to 10mm, and still more preferably 4mm to 6 mm. If the height H₄₄If it is too small, the effect of suppressing the stress concentration at the welded portion 47 is not obtained so much. If the height H₄₄If the amount is too large, the effect of suppressing the stress concentration at the welded portion 47 is reduced, and the material cost is increased.

As shown in fig. 6(a) to 6(c), the formation site of the welded portion 47 is determined according to the gate position 46 of the injection molding.

For example, in the loose flange 40A shown in fig. 6(a), only one gate position 46 indicated by a hollow arrow is arranged at the position where one rib 44 is arranged on the outer periphery of the loose flange 40A. The welded portion 47 is formed at the same portion as the rib 44A on the opposite side of 180 ° with respect to the one gate position 46.

In the loose flange 40B shown in fig. 6(B), two gate positions 46 are arranged at positions where two ribs 44 are arranged, which are separated by 180 ° from each other, on the inner periphery of the loose flange 40B. Two welded portions 47 are formed at the same positions as the two ribs 44A separated by 90 ° from the two ribs 44.

In the loose flange 40C shown in fig. 6(C), gate positions 46 are arranged at four positions on the inner peripheral surface of the loose flange 40C, which are separated by 45 ° from the ribs. The gate locations 46 are arranged at 90 ° intervals from each other. Each gate position 46 is disposed in an intermediate portion of two adjacent bolt holes 43. Four welding portions 47 are formed at the same positions as the four ribs. All four ribs become the welding position ribs 44A.

In any of the

loose flanges

40A, 40B, and 40C, the welding portion 47 and the welding position rib 44A are arranged apart from the bolt hole 43 in the circumferential direction.

When there are a plurality of gate positions 46 as in the

loose flanges

40B, 40C, a welded portion 47 is formed at an intermediate point between two gate positions 46 adjacent in the circumferential direction.

The welding position rib 44A may be different from the other ribs 44 in size and shape.

As shown in fig. 12, when the loose flange 40 is injection molded, the melt of the raw material resin including the reinforcing fibers is divided from the gate position 46 to both sides in the circumferential direction of the loose flange 40, and flows in the substantially circumferential direction toward the position to be the welded portion. Then, they are joined at the position to be the welded portion. The reinforcing fibers are oriented in the direction of flow of the melt.

Therefore, as shown in fig. 13, in the loose flange 40 (in the flange main body 41) at a position circumferentially apart from the welding position rib 44A, that is, at the non-welded portion, the reinforcing fibers of the fiber-reinforced resin are substantially oriented in the substantially circumferential direction. In the welded portion 47, the reinforcing fibers of the fiber-reinforced resin are oriented substantially in the radial direction (the direction intersecting the circumferential direction). In the welded portion 47, there are cases where the reinforcing fibers are less entangled with each other.

The two

tubes

10, 20 are joined as follows.

As shown in fig. 2, the pipe joint 13 is first assembled by fitting the loose flange 40 to the outer periphery of the stub 30.

The pipe end 12 is inserted into the pipe insertion portion 31 of the pipe joint 13. It is preferable that an adhesive is applied in advance to the inner peripheral surface of the pipe insertion portion 31 or the outer peripheral surface of the pipe end portion 12 to bond the pipe end portion 12 to the pipe insertion portion 31.

The pipe 10 to which the pipe joint 13 is attached and the target pipe 20 to which the pipe joint 23 is attached are aligned in a line, and the pipe joints 13 and 23 are held in opposition to each other with the seal 50 interposed therebetween.

The loose flange 40 is then angularly adjusted so that the bolt holes 43 of the coupler 13 are aligned with the bolt holes 25 of the coupler 23. Since the loose flange 40 can be rotated, the bolt holes 43, 25 can be easily aligned with each other. Further, the bolt holes 53 of the seal 50 are aligned with the bolt holes 43, 25.

Then, the bolt 60 is inserted through the bolt holes 43, 53, and 25 and fastened with the nut 61. Thereby, the pipe joints 13, 23 are joined to each other, and further, the

pipes

10, 20 are joined to each other.

By means of said bolt tightening, stresses are generated in the loose flange 40. In particular, in the welding position rib 44A, stress concentration may occur not only in the welded portion 47 but also in the inner corners 44g and the like on both sides with the welded portion 47 interposed therebetween. Therefore, the stress to be concentrated on the welded portion 47 can be dispersed, and the stress concentration in the welded portion 47 can be relaxed. In short, in the welded portion 47, not only the welded portion where the injection molding resin is formed, but also the orientation of the reinforcing fibers is different from the surrounding, and although there is a possibility that the reinforcing fibers are less entangled with each other, the deterioration of the mechanical properties caused by this can be suppressed.

As a result, the resistance of the loose flange 40 to the bolt fastening torque is improved, and the welded portion 47 can be prevented from being broken at the time of bolt fastening. Further, the loose flange 40 can also be improved in resistance to internal pipe pressure, thermal stress, and the like.

Next, another embodiment of the present invention will be explained. In the following embodiments, the same reference numerals are given to the same components as those of the above-described embodiments, and the description thereof is simplified.

< second embodiment >

As shown in fig. 9, in the second embodiment, the cross-sectional shape of the welding position rib 44B viewed from the circumferential direction of the loose flange 40 (the direction orthogonal to the paper surface in fig. 9) is a triangular shape (mountain shape). The welding position rib 44B has a top portion 44d disposed on the inner circumferential side of the intermediate portion between the inner and outer peripheries of the loose flange 40.

The present invention is not limited to the above embodiments.

For example, the number of the welding portions 47 and the welding position ribs 44A is not limited to one, two, or four, and may be three, or five or more.

The stub 30 may also be integrally formed with the tube 10.

The object to be joined is a member having a flange to be joined to the loose flange 40, and examples thereof include a joint, a tank, a pump, and the like, in addition to the pipe 20.

Example 1

The examples are described. The present invention is not limited to the following examples.

As shown in fig. 6(a), a loose flange 40 made of fiber-reinforced resin having one welding position rib 44A is manufactured by injection molding. The resin constituting the loose flange 40 is polypropylene (PP), and the reinforcing fiber is glass fiber.

The loose flange 40 is fitted around the stub 30 to produce the pipe joint 13. The stub 30 is made of polyvinyl chloride (PVC).

The pipe joint 13 is screwed to the target side pipe joint 23 through the seal 50 so as to face the target side pipe joint, thereby forming the pipe joint structure 1. The fastening torque was 200N · m.

As a result, no damaged portion is visible at all on the loose flange 40.

Comparative example 1

As comparative example 1 to example 1, a loose flange made of fiber-reinforced resin having no weld site rib 44A was produced by injection molding. The resin forming the loose flange plate is polypropylene (PP), and the reinforced fiber is glass fiber. The pipe joint is manufactured by fitting it into the outer periphery of the stub 30. The stub 30 is made of polyvinyl chloride (PVC).

The pipe joint is screwed to the target side pipe joint 23 through the seal 50 so as to face the pipe joint, thereby forming a pipe joint structure. The tightening torque was 80N · m.

As a result, breakage was confirmed along the welded portion of the loose flange.

Comparative example 2

As comparative example 2, a resin loose flange not having the welded portion 47 and the welding position rib 44A and not including reinforcing fibers was prepared. The resin forming the loose flange is polypropylene (PP). The pipe joint is manufactured by fitting the pipe joint around the stub 30. The stub 30 is made of polyvinyl chloride (PVC).

The pipe joint is screwed to the target side pipe joint 23 through the seal 50 so as to face the pipe joint, thereby forming a pipe joint structure. The tightening torque was 120N · m.

As a result, breakage was observed in the vicinity of the bolt holes of the loose flange.

From example 1, it is understood that a loose flange and a pipe joint with a loose flange having higher rigidity and excellent mechanical properties are obtained as compared with comparative examples 1-2.

Example 2

In example 2, the relationship between the width and height of the weld position rib 44A in the fiber-reinforced resin loose flange and the stress generated at the weld 47 was analyzed by computer simulation.

As an analytical model, a loose flange 40A having a weld site rib 44A shown in fig. 6(a) was used.

The diameter of the corresponding tube 10 was set to 50A to 200A (tables 1 and 2).

The width of the welding position rib 44A is set to 11.0mm to 17.0mm (table 1).

The height of the welding position rib 44A from the back surface 41b was set to 4.0mm to 6.0mm (table 2).

The stress generated in the welded portion 47 when the portion between the bolt holes 43 is deformed so as to be warped toward the rear (the front side of the paper surface in fig. 6 a) about the welding position rib 44A by fastening the bolts 60 inserted through the two bolt holes 43 on both sides with the welding position rib 44A therebetween was analyzed.

The results of the analysis of the stress according to the width of the welding position rib 44A are shown in table 1 and fig. 10.

The results of the analysis of the stress corresponding to the height of the weld site rib 44A are shown in table 2 and fig. 11.

[ Table 1]

< Rib height: 5mm >

Unit: MPa

[ Table 2]

Unit: MPa

It was confirmed that the welding position rib 44A has a width and a height that minimize the stress of the welding portion 47 according to the diameter.

If the width of the welding-position rib 44A is 10mm or more and 20mm or less, it can be said that the stress of the welding portion 47 falls within the allowable range.

If the height of the welding-position rib 44A is 2mm or more and 10mm or less, it can be said that the stress of the welding portion 47 falls within the allowable range.

It was confirmed that in the case of a general diameter of 50A to 200A, the width of welding position rib 44A is more preferably about 13.0mm to 16.0mm, and the height of welding position rib 44A is more preferably about 4.0mm to 6.0 mm.

Then, the orientation of the reinforcing fibers caused by the flow of the melt containing the reinforcing fiber resin during injection molding was analyzed by computer simulation.

As an analytical model, a loose flange 40A having a gate location 47 and a weld location rib 44A shown in fig. 6(a) was applied.

The thickness of the flange body 11 was set to 25 mm.

The width of the rib 44 is set to 13 mm.

The height of the rib 44 is set to 5 mm.

The results are shown in FIG. 12. Fig. 13 is an enlarged view of the peripheral portion of the welding-position rib 44A in fig. 12.

It was confirmed that the reinforcing fibers were oriented in the substantially circumferential direction of the loose flange in the non-welded portion away from the welded portion, and the reinforcing fibers were oriented in the substantially radial direction of the loose flange in the vicinity of the welded portion.

Description of the reference numerals

1 pipe joint structure

10 one tube

12 pipe end

13 pipe joint

20 object tube (joint object)

24 flange

30 stub end

31 pipe insertion part

32 horn part

33 inserting into the hole

40 loose sleeve flange

40A, 40B and 40C loose flange

41 flange main body

41a front surface

41b back side

44 Ribs

44A welding position rib (protection rib)

44f side end face

44g interior corner

44e protruding end face

44h outer corner

47 welding part

46 gate location

Claims

1. A loose flange rotatably fitted to an outer periphery of a butt end to be joined to a flange to be joined, the loose flange being made of a fiber-reinforced resin, the loose flange comprising:

an annular flange main body;

2. The loose flange of claim 1,

the welding position rib protrudes from a back surface of the flange main body facing a side opposite to the flange to be joined.

3. The loose flange of claim 2,

the weld site ribs extend in a radial direction of the flange body.

4. The loose flange of claim 3,

the welding position rib reaches the inner circumferential surface and the outer circumferential surface of the flange main body.

5. The loose flange of any one of claims 2 to 4,

a pair of inner corner portions are formed by side end surfaces on both sides in the width direction of the welding position rib and a back surface of the flange main body when viewed from the radial direction of the flange main body, and the welding portion is arranged to be sandwiched between these inner corner portions.

6. The loose flange of any one of claims 1 to 5,

the width of the welding position rib along the circumferential direction is 10mm to 20 mm.

7. The loose flange of any one of claims 1 to 6,

the projection height of the welding position rib from the flange main body along the axial direction is 2mm to 10 mm.

8. The loose flange of any one of claims 1 to 7,

in the flange main body, a plurality of ribs are formed so as to be separated from each other in the circumferential direction, and at least a part of the ribs is arranged on the welded portion to constitute the welding position rib.

9. The loose flange of any one of claims 1 to 8,

in the flange main body, bolt holes are formed in a rib circumferentially apart from the welding positions.

10. The loose flange of any one of claims 1 to 9,

the reinforcing fibers of the fiber-reinforced resin in the flange main body are oriented in a direction substantially intersecting with the circumferential direction at the welded portion, and are oriented in a substantially circumferential direction at a portion that is distant from the welded portion in the circumferential direction.

11. A loose flange rotatably fitted to an outer periphery of a butt end to be joined to a flange to be joined, the loose flange being made of a fiber-reinforced resin, the loose flange comprising:

an annular flange main body; and

12. A pipe joint provided at an end portion of one pipe and joined to a joining object, the pipe joint comprising:

the loose flange plate is provided with:

an annular flange main body;