JP6751689B2 - Fastening method of water pipe flange, seal member, and fastening structure of water pipe flange - Google Patents

Description

The present invention relates to a seal washer and a method for fastening a fluid pipe flange portion for sealing a bolt hole formed in a flange portion of a fluid pipe typified by a water pipe or the like.

Fluid pipes such as water pipes are usually joined by fastening flanges provided at the ends of the fluid pipes with fasteners such as nuts and bolts.

Fluid (water) may leak from between the flanges of the flange-joined fluid pipe due to external force such as an earthquake or aging. As one effective means for preventing this fluid leakage or for stopping the leakage when a fluid leakage actually occurs, for example, in Patent Document 1, the radial tips of the flange portions are connected to each other. A pipe reinforcing metal fitting for fixing a packing wound at a position of closing between the radial ends of the flange portions against the flange portion in order to seal the gap is disclosed.

Design Registration No. 1305825

In addition to the above, in order to prevent fluid leakage from the bolt holes formed in the flange portion, as shown in the partial cross-sectional view of FIG. 7, the bearing surfaces 20 and 30 of the bolt 2 or nut 3 and the flange portion 40 A seal washer 101 for sealing the bolt hole 40s is interposed between the two. The seal washer 101 has an insertion hole 110s formed of an elastic member and through which the shaft portion 21 of the bolt 2 is inserted, with a seal surface 110f set on the end surface on the flange portion side so as to be in close contact with the peripheral edge portion 40f of the bolt hole 40s. It has an annular seal member 110 and a frame member 111 that is harder than the seal member 110. When the bolt 2 and the nut 3 are tightened, the sealing surface 110f of the sealing member 110 is pressed against the flange portion 40 via the frame member 111, and the peripheral portion 40f of the bolt hole of the flange portion 40 and the sealing surface 110f come into close contact with each other to form a bolt. The holes 40s are sealed.

However, in the field, if the actual diameter of the bolt hole is slightly different from the standard diameter due to manufacturing error, or if the flanges are relatively offset in the radial direction, the flange surfaces are not parallel and slightly open. There are various environments such as when in a posture, and the size of the gap between the bolt hole and the shaft portion of the bolt can vary depending on the environment. As shown in FIG. 7, for example, this gap allows the axial center CL1 of the seal member 110 to deviate from the axial CL2 of the bolt hole 40s. As shown in the figure, if the offset of the seal member 110 with respect to the bolt hole 40s becomes large, the seal surface 110f may fall off from the bolt hole peripheral edge portion 40f, or the seal surface 110f may not be sufficiently sealed. There is a risk of causing liquid leakage from that site. It is desirable to tighten the bolt 2 and the nut 3 while aligning the sealing member 110 (bolt shaft portion 21) and the bolt hole 40s so that they are coaxial with each other, but this is a difficult task in the field. In particular, when liquid leakage actually occurs, it is difficult to see visually, so this is an extremely difficult task.

On the other hand, in order to prevent the seal surface 110f from falling off from the bolt hole peripheral edge portion 40f even if the axial center CL1 of the seal member 110 is offset in any radial direction with respect to the axial CL2 of the bolt hole 40s. One effective means is to increase the outer diameter of the seal member 110 to increase the area of the seal surface 110f. However, a space serving as a tool for tightening bolts and nuts must be secured between the main body of the water pipe 4 (fluid pipe), and the upper limit of the outer diameter of the seal member is naturally limited.

The present invention has been made in view of such a problem, and an object of the present invention is a seal washer capable of suppressing the seal surface from falling off from the peripheral portion of the bolt hole without increasing the diameter of the seal washer. And to provide a method of fastening the fluid pipe flange portion.

The present invention has taken the following measures in order to achieve such an object.

That is, the seal washer of the present invention is interposed between the bearing surface of the bolt or nut and the flange portion of the fluid pipe tightened by the bolt and the nut, and seals the bolt hole formed in the flange portion. An annular washer having an insertion hole formed of an elastic member and having an insertion hole through which the shaft portion of the bolt is inserted, with a sealing surface set at the end portion on the flange portion side for close contact with the peripheral portion of the bolt hole. A frame member which is arranged on the seat surface side of the bolt or nut and is harder than the seal member is provided, and the peripheral portion of the insertion hole of the seal member is provided with a seal member. It is characterized in that a fin portion that protrudes in the axial direction from the sealing surface in a natural state where no external force acts and can be inserted into a gap between the bolt hole and the shaft portion of the bolt is provided.

In this way, the peripheral edge of the insertion hole through which the bolt hole is inserted among the seal members protrudes axially from the seal surface in a natural state where no external force acts, and is inserted into the gap between the bolt hole and the shaft portion of the bolt. Since a possible fin portion is provided, if the fin portion is inserted into the bolt hole, the radial movement of the sealing member with respect to the bolt hole is restricted to some extent by the fin portion, and the sealing surface of the sealing member is flanged. It is possible to prevent the portion from falling off from the peripheral portion of the bolt hole.

In order to uniformly seal the bolt holes and improve stability, the fins form an annular shape along the peripheral edge of the insertion hole and between the fins and the inner peripheral surface from the tip to the base. It is preferable to have a tapered outer peripheral surface that becomes thicker in the radial direction.

With this configuration, the fin portion is pressed toward the back side of the bolt hole as the bolt and nut are tightened. Since the fin portion has a tapered outer peripheral surface in which the radial thickness between the fin portion and the inner peripheral surface increases from the tip end to the base end, elastic repulsive force is accumulated. At this time, if the axial center of the seal member is deviated in one radial direction with respect to the shaft of the bolt hole, the portion of the fin portion on one side in the radial direction is compressed as compared with the portion on the other end side. Will be done. Due to this difference in the amount of compression, an elastic rebound force acts in a direction in which the axial center of the bolt shaft portion coincides with the axis of the bolt hole, and the misalignment between the seal member and the bolt hole is corrected. Therefore, even if the bolt hole and the bolt shaft are misaligned during tightening, the elastic repulsive force of the sealing member appropriately corrects the misalignment between the sealing member and the bolt hole, so that the bolt hole can be uniformly sealed. It is possible to improve the stability. Since it exerts such a misalignment prevention function, it is particularly suitable when working in a leaked state where it is difficult to align, when there is a manufacturing error in the bolt hole diameter, or when the flanges are relative misaligned. Become.

Further, even after fastening (after construction), even if a load acts on the fluid pipe and a bending load acts on the bolt shaft portion, the fin portion elastically aligns the shaft of the bolt shaft portion with the shaft of the bolt hole. Since the repulsive force acts, it is possible to suppress or prevent the misalignment due to the bending load.

In the method of fastening the fluid pipe flange portion of the present invention, a bolt is inserted into a bolt hole formed in the flange portion of the fluid pipe, a nut is attached to the tip of the bolt, and the bolt and the nut are tightened to tighten the flange. A method of fastening a fluid pipe flange portion for fastening a portion, wherein a seal washer having a sealing member formed of an elastic member is interposed between the flange portion and the seating surface of the bolt or nut, and the seal is provided. A fin portion projecting from the member is inserted into a gap between the bolt hole and the shaft portion of the bolt, and the bolt and nut are tightened to fasten the flange portion.

In this way, if the fin portion protruding from the seal member constituting the seal washer is inserted into the bolt hole, the radial movement of the seal member with respect to the bolt hole is restricted to some extent by the fin portion. It is possible to prevent the sealing surface of the sealing member from falling off from the peripheral portion of the bolt hole of the flange portion.

In the above method, in order to uniformly seal the bolt holes and improve stability, the fin portion forms an annular shape along the peripheral edge portion of the insertion hole, and the inner peripheral surface is formed from the tip to the base end. It is preferable to have a tapered outer peripheral surface that increases the radial thickness between the two.

In the above method, in order to standardize the bolts and nuts and reduce the manufacturing cost, it is preferable that a spacer is interposed between the bearing surface of the bolts or nuts and the seal washer. By using the spacer in this way, common bolts and nuts can be used for various flange portions having different thicknesses, and it is possible to reduce the manufacturing cost by standardizing the parts.

The perspective view which shows typically the water pipe which was flange-joined by a bolt and a nut. FIG. 1 is a partial cross-sectional view of the AA portion of FIG. The figure which shows the seal washer of this invention. (A) Front view of the seal washer as viewed from the flange portion side. (B) Cross-sectional view passing through the axis of the seal washer. A partial cross-sectional view schematically showing a state in which the axis of the seal washer is deviated from the axis of the bolt hole. The perspective view which shows typically the installation work of a pipe reinforcement metal fitting. The perspective view which shows typically the installation work of a pipe reinforcement metal fitting. A partial cross-sectional view schematically showing a joint portion using a conventional seal washer.

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

As shown in FIG. 1, in the seal washer 1, the flanges 40 and 40 provided at the ends of the water pipe 4 (an example of a fluid pipe) are fastened to each other by using bolts 2 and nuts. -It is used when joining 4, and specifically, as shown in FIG. 2, the bearing surface 20/30 of the bolt 2 or the nut 3 and the flange portion of the water pipe 4 tightened by the bolt 2 and the nut 3. It is used to seal the bolt hole 40s formed in the flange portion 40, which is interposed between the 40 and the flange portion 40. Note that FIG. 2 is a partial cross-sectional view of the AA portion in FIG.

As shown in FIGS. 2 and 3, the seal washer 1 is made of an annular seal member 10 formed of an elastic member such as rubber and having an insertion hole 10s through which the shaft portion 21 of the bolt 2 is inserted, and the seal member 10. Also has a frame member 11 arranged on the seat surface 20/30 side of the bolt 2 or the nut 3. Note that FIG. 3A is a front view of the seal washer 1 viewed from the flange portion side, and FIG. 3B is a cross-sectional view of the seal washer 1 passing through the axial center CL1.

The sealing member 10 has a sealing surface 10f set at an end portion on the flange portion side so as to be in close contact with the bolt hole peripheral edge portion 40f, and the sealing surface 10f forms a flat surface orthogonal to the axial center CL1. The insertion hole 10s formed in the seal member 10 is set to a diameter substantially matching the outer diameter of the shaft portion 21 of the bolt 2 in order to seal between the insertion hole 10s and the shaft portion 21 of the bolt 2.

A fin portion 12 is provided on the peripheral edge of the insertion hole 10s of the seal member 10 so as to project axially from the seal surface 10f in a natural state where no external force acts. The fin portion 12 is set to a size such that at least the tip portion thereof can be inserted into the gap between the bolt hole 40s and the shaft portion 21 of the bolt 2. The fin portion 12 has an annular shape along the peripheral edge portion of the insertion hole 10s, and has a tapered outer peripheral surface 12b whose radial thickness between the fin portion 12 and the inner peripheral surface 12a increases from the tip end to the base end. The fin portion 12 has a symmetrical shape around the axial center CL1 so that the cross-sectional shape passing through the axial center CL1 is the same at any portion in the circumferential direction. Further, the radial outer end of the tapered outer peripheral surface 12b and the radial inner end of the sealing surface 10f are connected by an arc surface, and stress is concentrated on the connecting portion between the tapered outer peripheral surface 12b and the sealing surface 10f. Avoid doing.

In the present embodiment, as illustrated in FIG. 3 (b), the shaft outer diameter D ₁ of the bolt and 16 mm, a bolt hole diameter as a standard in the case of the Fai19mm, the outer diameter D of the tip of the fin portions 12 ₂ is set to φ17.5 mm (= bolt shaft outer diameter + 1.5 mm), and the outer diameter D ₃ of the base end portion of the fin portion 12 is set to φ 19.5 mm (= bolt hole diameter + 0.5 mm). The protrusion distance D ₄ of the fin portion 12 from the sealing surface 10f is 3 mm. In this way, the outer diameter of the tip of the fin portion 12 is set smaller than the diameter of the bolt hole so that the fin portion can be inserted into the gap between the bolt hole 40s and the bolt shaft portion 21. Further, the outer diameter of the base end portion of the fin portion 12 is set to be larger than that of the bolt hole 40s so that the peripheral edge of the bolt hole 40s is brought into close contact with the fastening. As a result, even if the bolt hole diameter is smaller or larger than the standard value, the fin portion 12 fits into the bolt hole when the bolt and nut are fastened, so that the fin portion 12 is sealed without twisting during fastening. Is possible.

As shown in FIGS. 2 and 3, the frame member 11 is made of a material (for example, metal) harder than the sealing member 10, and is manufactured by, for example, sheet metal processing or casting. The frame member 11 has an annular bottom wall 11a in which a hole 11s for inserting the shaft portion 21 of the bolt 2 is formed, and a side wall 11b that rises axially from the peripheral edge of the bottom wall 11a, and the bottom wall 11a The side wall 11b and the side wall 11b form a shape for accommodating a part of the seal member 10. The axial thickness of the side wall 11b is set to be thinner than the thickness from the anti-flange side end surface of the seal member 10 to the seal surface 10f, whereby the frame member 11 (the tip of the side wall 11b) and the flange portion 40 are set to be thinner. A gap is provided between them to set a compression allowance for compressing the seal member 10. At the time of use, it is preferable that the seal member 10 and the frame member 11 are adhered with an adhesive. By adhering, it is possible to prevent the seal member 10 from coming off from the frame member 11 due to water pressure and being damaged.

Next, using the seal washer 1 having the above configuration, as shown in FIG. 2, the bolt 2 is inserted into the bolt hole 40s formed in the flange portion 40 of the water pipe 4, and the nut 3 is attached to the tip portion of the bolt 2. A method of tightening the bolt 2 and the nut 3 to fasten the flange portion 40 will be described. Here, in order to arrange the seal washers 1 on the bolt side and the nut side, respectively, an example in which two seal washers are used is shown. First, the existing bolts and nuts inserted into the bolt holes are taken out one by one, and the bearing surface of the flange is cleaned. After that, it is connected with a bolt and a nut having a seal washer 1 interposed therebetween.

First, a state in which the bolt shaft portion 21 through which the first seal washer 1a (1) is inserted is passed through the bolt hole 40s, and the first seal washer 1a is interposed between the flange portion 40 and the seat surface 20 of the bolt 2. And. At this time, the fin portion 12 projecting from the seal member 10 is inserted into the gap between the bolt hole 40s and the shaft portion 21 of the bolt. As a result, the radial movement of the seal member 10 with respect to the bolt hole 40s is restricted to some extent by the fin portion 12. A spacer 5 may be interposed between the seat surface 20 of the bolt 2 and the first seal washer 1a, if necessary.

Next, the second seal washer 1b (1) is inserted into the tip of the bolt shaft portion 21, and the nut 3 is attached to the tip of the bolt 2. At this time, the fin portion 12 projecting from the seal member 10 is inserted into the gap between the bolt hole 40s and the bolt shaft portion 21. As a result, the radial movement of the seal member 10 with respect to the bolt hole 40s is restricted to some extent by the fin portion 12. A spacer 5 may be interposed between the seat surface 30 of the nut 3 and the second seal washer 1b, if necessary. By using the spacer 5 in this way, common bolts and nuts can be used for various flange portions having different thicknesses, and it is possible to reduce the manufacturing cost by standardizing the parts.

Then, the bolt 2 and the nut 3 are tightened to fasten the flange portion 40. As the bolt 2 and the nut 3 are tightened, the fin portion 12 is pressed toward the inner side of the bolt hole 40s and is slightly elastically deformed. As shown in FIG. 3B, the fin portion 12 has a tapered outer peripheral surface 12b whose radial thickness between the fin portion 12 and the inner peripheral surface 12a increases from the tip end to the base end, so that the fin portion 12 is accompanied by elastic deformation. Accumulates elastic repulsive force. At this time, for example, as schematically shown in FIG. 4, if the axial center CL1 of the seal member is displaced to one side in the radial direction with respect to the axis CL2 of the bolt hole 40s, one side of the fin portion 12 in the radial direction The portion P1 is compressed more than the portion P2 on the other side in the radial direction. Due to this difference in the amount of compression, the elastic rebound force F acts in the direction of matching the axial center CL1 of the seal member 10 with the axis CL2 of the bolt hole 40s, and the misalignment between the seal member 10 and the bolt hole 40s is corrected. To.

Therefore, even if the bolt hole 40s and the seal member 10 (bolt shaft portion 21) try to be misaligned at the time of fastening, the elastic rebound force F acts in the direction of eliminating the misalignment between the seal member 10 and the bolt hole 40s by the fin portion 12. As a result, the misalignment between the sealing member 10 and the bolt hole 40s is corrected, so that the bolt hole 40s can be uniformly sealed over the circumferential direction, and the stability can be improved. In particular, it is suitable when the work is performed in a leaked state where it is difficult to align the flanges, when there is a manufacturing error in the bolt holes, or when the flanges are relatively misaligned with each other.

Further, even after fastening, even if a bending load acts on the bolt shaft portion 21 due to a load on the water pipe 4 (fluid pipe), the sealing member 10 due to the bending load is provided by the misalignment correction function of the fin portion 12. It is possible to suppress or prevent misalignment.

It is preferable to replace the bolts and nuts with seal washers in advance by the above procedure, and then attach the pipe reinforcing metal fittings shown in Design Registration No. 13058525 to the flange portion. Although detailed description will be omitted, as shown in FIG. 5, a packing 61 such as a rubber plate is adhered in a ring shape with an adhesive and arranged at the radial tip portion of the flange portion 40, as shown in FIG. , The plurality of divided pieces 60a and 60b constituting the pipe reinforcing metal fitting 60 are fastened to each other with bolts 62 and nuts 63. If water leaks between the flanges 40 and 40, leave one of the multiple bolt holes unfastened with bolts and nuts with seal washers, and drain from there. While attaching the pipe reinforcing metal fitting 60, finally tighten the remaining bolt holes with bolts and nuts with seal washers.

Here, the case where the conventional seal washer having the above-mentioned pipe reinforcing metal fitting and having the above-mentioned seal member without the fin portion is used, and the case where the seal washer of the present invention having the above-mentioned seal member provided with the fin portion is used. When a water leakage confirmation test was conducted, it was possible to improve the withstand voltage by about 1 MPa when the fin portion was provided as compared with the case where there was no fin portion. In the above comparison, other conditions such as tightening torque of bolts and nuts are matched.

Further, when the seal washer of the present invention was used in a state where water was leaking from the bolt hole at a general water pressure, the water could be stopped by hand tightening. It is considered that this is because the misalignment correction of the seal member by the fin portion was properly exhibited.

The present invention is not limited to the above-described embodiments, and various improvements and modifications can be made without departing from the spirit of the present invention.

For example, in the present embodiment, the fin portion 12 has a so-called tapered shape in which the thickness increases in the radial direction from the tip end to the base end, but the fin portion 12 can be inserted between the bolt hole and the bolt shaft portion. As long as the radial movement of the seal member with respect to the bolt hole can be suppressed to some extent, the shape may be such that the radial thickness does not change. Further, in the present embodiment, the outer peripheral surface 12b of the fin portion 12 and the sealing surface 10f are continuous on an arc surface, but other shapes may be used. Further, in the present embodiment, it is preferable that the fin portion 12 projects at least 5 mm or more in order to accurately obtain the effect of being caught in the bolt hole 40s.

In the present invention, the fluid pipe is not limited to the water pipe, and may be a fluid pipe through which various liquids and gases flow.

1 ... Seal washer 10 ... Seal member 10f ... Seal surface 10s ... Insertion hole 12 ... Fin portion 12b ... Outer peripheral surface 12a ... Inner peripheral surface 11 ... Frame member 2 ... Bolt 20 ... Bolt seat surface 21 ... Bolt shaft portion 3 ... Nut 30 ... Nut seat surface 4 ... Water pipe (fluid pipe)
40 ... Flange portion 40s ... Bolt hole 40f ... Peripheral portion of bolt hole 5 ... Spacer

Claims (5)

A bolt is inserted into a bolt hole formed in a flange portion of a water pipe, a nut is attached to the tip portion of the bolt, and the bolt is provided with a sealing member interposed between the flange portion and the bolt or the nut. And a method of fastening the water pipe flange portion by tightening the nut and fastening the flange portion.
The sealing member is formed of an elastic member and has an annular shape having an insertion hole through which the shaft portion of the bolt is inserted and a sealing surface for close contact with the peripheral portion of the bolt hole. An annular fin portion that protrudes in the axial direction from the sealing surface is provided in a natural state in which
The annular fin portion has a tapered outer peripheral flat surface whose radial thickness between the tip and the inner peripheral surface increases from the tip to the base end, and the outer diameter of the tip portion of the outer peripheral flat surface is the bolt. It is formed smaller than the hole and
The sealing member is interposed between the flange portion and the bearing surface of the bolt or the nut, the annular fin portion is inserted into the bolt hole, and the bolt and the nut are tightened to fasten the flange portion. And
In the fastened state, the entire inner peripheral surface of the sealing member including the annular fin portion is in close contact with the portion of the shaft portion of the bolt where the thread groove is not formed.
The sealing surface, Ri flat surface der perpendicular to the axis of the bolt in a natural state where no external force acts,
A method for fastening a water pipe flange portion, wherein the entire inner peripheral surface of the sealing member in the axial cross section is a flat surface in a natural state in which no external force acts . The method according to claim 1, wherein the protruding distance of the fin portion from the sealing surface is 3 mm or 5 mm or more. A sealing member that is interposed between the bearing surface of a bolt or nut and the flange portion of a water pipe tightened by the bolt or nut, and seals a bolt hole formed in the flange portion.
The sealing member is formed of an elastic member and has an annular shape having an insertion hole through which the shaft portion of the bolt is inserted and a sealing surface for close contact with the peripheral portion of the bolt hole, and an external force is applied to the peripheral portion of the insertion hole. An annular fin portion that protrudes in the axial direction from the sealing surface is provided in a natural state in which
The annular fin portion has a tapered outer peripheral flat surface whose radial thickness between the tip and the inner peripheral surface increases from the tip to the base end, and the outer diameter of the tip portion of the outer peripheral flat surface is the bolt. It is formed smaller than the hole and can be inserted into the bolt hole.
The entire inner peripheral surface of the sealing member including the fin portion is brought into close contact with the portion of the shaft portion of the bolt where the thread groove is not formed.
The sealing surface, Ri flat surface der perpendicular to the axis of the bolt in a natural state where no external force acts,
A seal member in which the entire inner peripheral surface of the seal member in an axial cross section is a flat surface in a natural state in which no external force acts . The sealing member according to claim 3, wherein the protruding distance of the fin portion from the sealing surface is 3 mm or 5 mm or more. Bolts and nuts that tighten the flange of water pipes,
The sealing member according to claim 3 or 4, which is interposed between the seat surface of the bolt or nut and the flange portion of the water pipe and for sealing the bolt hole formed in the flange portion. Fastening structure of water pipe flange.

Images