JP2021148270A - Pipe coupling - Google Patents

Abstract

To suppress a pipe coupling, having an insertion port of a pipe and a receiving port of a pipe connected in an insertable/extractable state, from having pressure loss of water running on a coupling part inner surface.SOLUTION: The present invention relates to an earthquake-proof coupling part which employs an US type ductile iron pipe (R system) etc. A pressure loss suppression cover 10c sectioned in a bellows shape is provided between an insertion port tip end face 1a and a receiving port inner end face 2a. Even when means (gap S) for absorbing insertion which is installed crossing a reverse fault is employed between the insertion port tip end face 1a and receiving port inner end face 2a as shown in Fig.4 (a), the cover 10c can suppress water from entering the inner (inner face) side of a receiving port 2 from the gap S during water conduction, so variation in water conduction cross sectional area is small and pressure loss is hardly caused. Consequently, a risk of a drop in pressure in the pips due to pressure loss is extremely small. As the reverse fault is displaced, a conduit is loaded with force in its compressing direction, but as shown in Fig.4 (b), the insertion port 1 is inserted into the receiving port 2 by contracting the cover 10c and moves up to the receiving port inner end face 2a, thereby absorbing its displacement.SELECTED DRAWING: Figure 4

Description

The present invention relates to a pipe fitting in which the insertion port of one pipe is removably connected to the socket of another pipe.

Conventionally, a US-type ductile iron pipe (LS method) has been used as a seismic pipe having a large diameter, for example, a nominal diameter of 800 or more, which is brought into the shield. In the pipe joint of the US type ductile iron pipe (LS method), as shown in FIG. 8, the insertion port 1 of one pipe P is inserted into the receiving port 2 of the other pipe P with the rubber ring 3 interposed therebetween. A lock ring 4 is provided on the inner surface of the receiving port 2, and a protrusion 5 for locking to the lock ring 4 is formed on the outer surface of the tip end portion of the insertion port 1. It is a configuration that can be inserted and removed by moving from the state shown in the figure away from the lock ring 4 to the time when the lock ring 4 is locked.

The pipe joint portion of this US type ductile iron pipe (LS method) has a split ring 6 and a push ring 7 interposed between the outer peripheral surface of the insertion port 1 and the inner peripheral surface of the receiving port 2, and the tip surface 1a of the insertion port and the back of the receiving port. A joint rod 8 is interposed between the end faces 2a, and mortar a is filled between the insertion port tip surface 1a and the receiving port back end surface 2a. This filling of the mortar a is for reducing the unevenness of the inner surface of the pipe and suppressing the pressure loss during water flow. However, since it is necessary to fill the mortar a after interposing the split ring 6, the push ring 7, and the joint rod 8 (after joining the joint), there is a problem in workability such as a large number of work man-hours. be.

Therefore, the US-type ductile iron pipe (R method) shown in FIG. 9 has been developed. In this US-type ductile iron pipe (R method), the split ring 6 is omitted, the push ring 7 is made smaller, and a plate-shaped spacer 9 is interposed between the push ring 7 and the back end surface 2a of the receiving port via a spacer rubber 9a. It is a configuration that has been made. With this configuration, by omitting the split ring 6 and making the push ring 7 smaller, it becomes possible to insert the insertion port 1 up to the back end surface 2a of the receiving port 2 as shown in FIG. As a result, it is no longer necessary to fill the mortar a.

Japanese Unexamined Patent Publication No. 11-13965 Japanese Unexamined Patent Publication No. 11-315978

By the way, when a seismic line is installed at a position crossing a reverse fault by the above US type ductile iron pipe (R method), if the fault is displaced due to an earthquake or the like, a force in the compression direction is applied to the line. Therefore, as shown in FIG. 9A, if the insertion port 1 is abutted against the back end surface 2a of the receiving port, the fault displacement may not be absorbed by the joint portion.
Therefore, as shown in FIG. 3B, the insertion amount of the insertion port 1 is suppressed, a gap S is provided between the insertion port 1 and the back end surface 2a of the receiving port, and the fault displacement is caused by the gap S. It may take measures to absorb.
However, if the gap S is provided, pressure loss occurs because the cross-sectional area of the water flow changes due to water entering the space (with the socket body) where the spacer 9 is located from the gap S during normal water flow. May cause a drop in pressure inside the pipe. When the pressure drops, it becomes impossible to secure water at the required pressure downstream, or it becomes necessary to raise the water pressure more than necessary upstream to secure it.

Incidentally, Patent Document 1 discloses a technique in which a plurality of hollow rings are interposed between the insertion port and the back end surface of the receiving port to reduce the unevenness (step) of the inner surface of the joint portion of the insertion port and the receiving port. ing. However, this joint portion is related to a power cable pipe, and the reduction of the step due to the hollow ring is intended to improve the wiring work.
Further, Patent Document 2 discloses a technique in which a liner is provided between the insertion port and the back end surface of the receiving port, and the inner surface of the joint portion of the liner is made uneven by the liner. However, this technique is not a pipe joint in which the insertion port of one pipe can be inserted and removed from the socket of another pipe, and as a result, the effect of eliminating the pressure loss on the inner surface of the pipe of the joint portion is recognized by the liner. The liner is originally intended to eliminate the insertion of the insertion port into the socket to resist the unequal force, and is not to suppress the pressure loss on the inner surface of the pipe.

Under the above circumstances, the present invention suppresses the pressure loss of water flow on the inner surface of the joint portion of a pipe joint in which the insertion port of one pipe is connected to the socket of another pipe so as to be removable. Is the subject.

In order to achieve the above object, the present invention presents the end face (tip surface) of the tip end surface (tip surface) of the insertion port and the socket in a pipe joint in which the insertion port of one pipe is connected to the socket of another pipe so that it can be inserted and removed. A pressure loss suppression cover is provided to prevent water from entering the inside (with a socket body) from between the back end faces of the.
As shown in FIG. 9B, the insertion amount of the insertion port 1 is suppressed, a gap S is provided between the insertion port 1 and the back end surface 2a of the receiving port, and the insertion port 1 is inserted through the gap S. Even if a means for absorbing (shrinkage allowance of the joint) is adopted, pressure loss occurs because the cover can prevent water from entering the inner (inner surface) side of the socket through the gap when water is passed. Hateful. Therefore, there is very little risk of causing a pressure drop in the pipe due to pressure loss.

A specific configuration of the present invention is that in a pipe joint in which an insertion port of one pipe is inserted and removed through a rubber ring through a receiving port of another pipe, the end face of the tip end portion of the insertion port and the receiving port A structure is adopted in which a pressure loss suppression cover is provided between the back end faces to prevent water from entering the inside.
At this time, the pipe joint is provided with a lock ring on the inner surface of the socket, and a protrusion for locking to the lock ring is formed on the outer surface of the tip of the insertion port. Can be adopted so that it can be inserted and removed by moving between the lock ring and the back end surface of the socket.

In these configurations, the pressure loss suppressing cover may be provided between the end surface of the tip end portion of the insertion port and the back end surface of the receiving port so as to be expandable and contractible. At this time, if the inner peripheral surface of the cover is set to the same level as the inner surface of the pipeline as much as possible, the pressure loss of water flowing on the inner surface of the cover is also reduced.
As the stretchable cover, a cover having a bellows-shaped cross section from the end surface of the tip end portion of the insertion port toward the back end surface of the socket is adopted.

In the present invention, as described above, the cover facilitates the flow of water, so that pressure loss is extremely unlikely to occur on the inner surface of the joint portion during normal water flow.

A cross-sectional view of an embodiment of a pipe joint according to the present invention is shown, (a) is a state in which the insertion port and the back end surface of the socket are separated, and (b) is a state in which the insertion port is inserted to the back of the socket. The front view of the cover of the same embodiment is shown, (a) is at the time of loading, and (b) is at the time of transportation. Sectional view of another embodiment The cross-sectional view of still another embodiment is shown. FIG. Sectional view of still another embodiment Sectional view of still another embodiment Sectional view of still another embodiment Sectional view of the conventional example The working sectional view of the conventional example is shown. FIG.

An embodiment according to the present invention is shown in FIGS. 1 and 2, and this embodiment is a seismic joint portion made of a US-type ductile iron pipe (R method) having a nominal diameter of 1500 to 2600, and as shown in the figure, Similar to FIG. 9B, the insertion port 1 of one tube P is inserted into the receiving port 2 of the other tube P with the rubber ring 3 interposed therebetween. A lock ring 4 is provided on the inner surface of the receiving port 2, and a protrusion 5 for locking to the lock ring 4 is formed on the outer surface of the tip end portion of the insertion port 1. Therefore, the insertion port 1 can be inserted and removed without being detached because the protrusion 5 moves between the lock ring 4 and the back end surface 2a of the receiving port 2.
Further, a push ring 7 is interposed between the tip end portion of the insertion port 1 and the inner surface of the socket 2, and a spacer 9 is interposed between the push ring 7 and the back end surface 2a of the socket 2 via a spacer rubber 9a.

The above configuration is the same as the conventional one, and in the present invention, in the space S of the end surface (tip surface) 1a of the tip end portion of the insertion port and the back end surface 2a of the socket, at least the entire circumference of the inside (with the socket body) is covered with a cylindrical shape. The feature is that it is closed with 10.
An example of the cover 10 is shown in FIG. 2, and the cover 10a (hereinafter, 10a, 10b, and 10c are collectively referred to as 10) is a cylindrical one made of rubber, resin, or the like and having shape retention and flexibility. It is composed of an annular body portion 11 and a flange portion 12 extending over the entire length of the side edge of the body portion 11, and a part 13 around the circumference is cut out. The collar portion 12 may be formed continuously or intermittently over the entire circumference.

As shown in FIG. 2B, the cover 10a is brought into the pipeline in a state where the notch portions 13 are stacked one above the other and the diameter is reduced, and the insertion port 1 of one pipe P is the other pipe P. FIG. 1A shows a state in which a rubber ring 3 or a lock ring 4 is inserted into the receiving port 2 and a spacer 9 is interposed between the push ring 7 and the back end surface 2a of the receiving port via the spacer rubber 9a. As shown in the above, the collar portion 12 is addressed to the back end surface 2a of the socket, and one end edge of the body portion 11 is addressed to the end surface of the push ring 7. It suffices if the cover 10a is maintained between the push ring 7 and the back end surface 2a of the socket by these two addresses, but if the mounting state is not stable, one end of the collar portion 12 and the body portion 11 may be fixed by adhesion or screwing. It is preferable to fix it. Further, the edge of the notch portion 13 is connected with a tape or the like to be integrated.

In this way, when the cover 10a is provided, at the position crossing the reverse fault, as shown in FIG. 1A, the insertion amount of the insertion port 1 is suppressed, so that the insertion port 1 and the back end surface 2a of the socket are Even if a gap S is provided between the gaps S and a means for absorbing the insertion of the insertion port 1 (the shrinkage allowance of the joint) is adopted by the gap S, the cover 10a allows the cover 10a to receive the socket from the gap S. Since it is possible to prevent water from entering the inner (inner surface) side of No. 2, pressure loss is unlikely to occur. Therefore, there is very little risk of causing a pressure drop in the pipe due to pressure loss.
On the other hand, if the reverse fault is displaced, a force in the compression direction is applied to the conduit, but as shown in FIG. It moves to 2a and absorbs the displacement. That is, since the thickness of the cover 10a can be reduced, it is possible to secure the same joint compression allowance (insertion allowance for the insertion port 1) as compared with the case where the cover 10a is not attached.

In this embodiment, fluid analysis was performed between the case where the cover 10a was not provided and the case where the cover 10a was loaded, and it was found that the latter can suppress the pressure loss by about 30% as opposed to the former.

The embodiment shown in FIG. 3 is a 10b in which one end of the body portion 11 of the cover 10a is extended to the inner surface of the push ring 7 in the embodiment of FIG. 1, and one end thereof is supported by the inner surface of the push ring 7 and is therefore stable. ..

The embodiment shown in FIG. 4 is 10c in which the cover 10a has a bellows-shaped cross section and is expandable and contractible in the length direction (cylindrical axis direction) in the embodiment shown in FIG. Similarly, the cover 10c is made of rubber, resin, or the like, and flanges 14 around both ends of the body portion 11 are inserted and abutted between the front end surface 1a of the opening and the back end surface 2a of the receiving port, and are provided between them.
It is sufficient that the cover 10c is maintained between the front end surface 1a of the insertion port and the back end surface 2a of the receiving port by the contact between the two, but if the mounting state is not stable, the flange 14 may be fixed by adhesion or screwing. preferable. The screw can be fastened with a bolt 14a as shown in FIG. The cover 10c provided between the front end surface 1a of the insertion port and the back end surface 2a of the socket so that the thickness in the radial direction falls within the thickness of the tube P in the state where the bellows are extended (FIGS. 4 (a) and 5). Set to. That is, the inner surface of the cover 10c (the lower edge of the valley of the bellows) is appropriately set by an experiment or the like so as not to interfere with water flow.

When this cover 10c is provided, as shown in FIGS. 4 (a) and 5 at a position crossing the reverse fault, the insertion amount of the insertion port 1 is suppressed, so that the insertion port 1 and the back end surface of the receiving port 2a are provided. Even if a gap S is provided between the gaps S and a means for absorbing the insertion of the insertion port 1 (the shrinkage allowance of the joint) is adopted by the gap S, the cover 10c allows the cover 10c to receive the socket from the gap S. Since it is suppressed that water enters the inner (inner surface) side of No. 2, pressure loss is less likely to occur. Therefore, there is very little risk of causing a pressure drop in the pipe due to pressure loss.
On the other hand, if the reverse fault is displaced, a force in the compression direction is applied to the conduit, but as shown in FIG. 4 (b), the insertion port 1 is inserted into the receiving port 2 by reducing the cover 10c. It can move to the back end surface 2a of the socket and absorb the displacement.

Each of the above embodiments was a seismic pipe joint using a US type ductile iron pipe (R method), but the insertion port 1 of one pipe P is inserted into the receiving port 2 of the other pipe P with the rubber ring 3 interposed therebetween. In rare cases, a lock ring 4 is provided on the inner surface of the receiving port 2, and a protrusion 5 for locking to the lock ring 4 is formed on the outer surface of the tip end portion of the insertion port 1, and the insertion port 1 is formed with the protrusion. The present invention can be adopted in a pipe joint in which 5 is movablely inserted and removed between the lock ring 4 and the back end surface 2a of the receiving port 2. For example, it can be used for the NS type pipe joint shown in FIG. 6, the S type pipe joint shown in FIG. 7, and the like.

It should be noted that the embodiments disclosed this time are exemplary in all respects and are not considered to be restrictive. The scope of the present invention is indicated by the claims and is intended to include all modifications within the meaning and scope equivalent to the claims.

1 Insertion port 1a Insertion port tip surface 2 Receiving port 2a Receiving port back end surface 3 Rubber ring 4 Lock ring 5 Protrusion 7 Push ring 9 Spacer 9a Spacer rubber 10, 10a, 10b, 10c Cover 11 Cover body 12 Same flange 13 Same Notch 14 Flange 14a Bolt (screw)

Claims (4)

In a pipe joint in which the insertion port (1) of one pipe (P) is inserted into the socket (2) of another pipe (P) with a rubber ring (3) interposed therebetween.
A pressure loss suppressing cover (10, 10a, 10b, 10c) is provided between the end surface (1a) of the tip end portion of the insertion port and the back end surface (2a) of the socket (2) so that water does not enter the inside thereof. Pipe fitting. A lock ring (4) is provided on the inner surface of the socket (2), and a protrusion (5) for locking to the lock ring (4) is formed on the outer surface of the tip of the insertion port (1). The insertion port (1) according to claim 1, wherein the protrusion (5) moves between the lock ring (4) and the back end surface (2a) of the receiving port (2) so that the insertion port (1) can be inserted and removed. Pipe fitting. The pressure loss suppression cover (10, 10a, 10b, 10c) that can be expanded and contracted is provided between the tip end surface (1a) of the insertion port (1) and the back end surface (2a) of the socket (2). The pipe fitting according to claim 1 or 2. The pressure loss suppression cover (10c) has a bellows-shaped cross section and can be expanded and contracted from the tip end surface (1a) of the insertion port (1) toward the back end surface (2a) of the socket (2). The pipe fitting according to claim 3.

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