JP3244928U - Connection structure between resin pipe and flexible joint - Google Patents

Abstract

[Problem] To provide a resin pipe that prevents the diameter of the end of the resin pipe from shrinking due to the effects of heat etc. at the connection point and suppresses the drop in liquid tightness even when the resin pipe is connected to a cast iron flexible joint. Provides a connection structure with flexible joints. In the connection structure between a resin pipe 200 and a flexible joint 100, a resin pipe 200 with a packing 30 fitted thereon is inserted into a connection port 11 of a joint body 10, and the flexible joint 100 is configured. The packing 30 is pressed against the connection port 11 and the resin pipe 200 by the pressing tool 20, and the cylindrical core 50 press-fitted into the end of the resin pipe 200 suppresses the diameter reduction deformation of the resin pipe 200. [Selection diagram] Figure 1

Description

The present invention relates to a connection structure between a resin pipe and a flexible joint, and more particularly to a connection structure between a resin pipe and a flexible joint that can suppress a decrease in liquid tightness due to the influence of heat or the like at the connection point.

Conventionally, polypropylene resin pipes have been known as resin pipes for drainage. Some commercially available polypropylene resin pipes have a two-layer structure in which a fiber-reinforced thermoplastic resin reinforced with glass fiber is placed on the outer layer of the resin pipe to increase rigidity in high-temperature areas. This material is known as a drainage piping material that is lightweight and has excellent heat resistance and chemical resistance. As a joint for connecting such polypropylene resin pipes, a heat-sealing type joint has generally been adopted in many cases.

However, because heat-sealed joints have heating wires built-in, the construction of the joint itself is complicated and costly, and when connecting polypropylene resin pipes, it is necessary to use terminals to energize the heating wires. Problems have been pointed out, such as the need for pins, indicators and controllers to control the fusion state, which not only requires skill, but also requires long hours of connection work. Patent Document 1, which is a prior example, describes a heat-sealing mechanical joint.

In view of this situation, there has been a desire to use cast iron flexible joints for connection with resin pipes. Therefore, a cast iron flexible joint and a polypropylene resin pipe were connected using the connection structure shown in FIG. 6, and then a high-temperature water flow test was conducted.

FIG. 6 is a sectional view showing a connection structure between a polypropylene resin pipe 200 and a cast iron flexible joint 100 used in a running water test. In the figure, a flexible joint 100 includes a joint body 10 having a connection port 11 and a pressing tool 20, and a collar 12 is provided around the opening of the connection port 11 in the joint body 10. It is being Further, the end of the resin pipe 200 with the packing 30 fitted thereon is inserted into the connection port 11 of the joint body 10. The collar portion 12 of the joint body 10 and the pressing tool 20 are fastened together using a fastening tool 40 made of bolts and nuts. In this connection structure, the packing 30 is tightened in the axial direction by the joint body 10 and the pressing tool 20, thereby coming into pressure contact with the connection port 11 and the resin pipe 200, thereby exhibiting watertightness. Further, the resin pipe 200 and the joint body 10 are connected to be able to swing relative to each other using the vicinity of the attachment point of the packing 30 as a fulcrum.

A running water test was conducted by flowing high-temperature water through the flexible joint 100 and the resin pipe 200, which were connected using the connection structure shown in FIG. A phenomenon in which a dent was formed at the end and the outer diameter was reduced was confirmed. However, if the outer diameter of the end of the resin pipe 200 is reduced in this way, there is a concern that the packing 30 may be compressed insufficiently in the axial direction, and in some cases, the watertightness of the packing 30 may be impaired, resulting in a water leakage accident. It was discovered that there is a risk of this happening. Note that Patent Document 2 as another prior example describes a mechanical joint used for connecting cast iron pipes.

Japanese Patent Application Publication No. 5-248586 Utility Model Publication No. 6-69574

The present invention was developed in view of the above circumstances, and even when a resin pipe is connected to a cast iron flexible joint, the outer diameter of the end of the resin pipe does not shrink due to the influence of heat, etc. It is an object of the present invention to provide a connection structure between a resin pipe and a flexible joint in which concerns about insufficient compression in the axial direction of the packing and loss of watertightness due to the packing are suppressed.

In the connection structure between a resin pipe and a flexible joint according to the present invention, the end of the resin pipe with the packing attached to the outside is inserted into the connection opening of the joint body, and the end part of the resin pipe is inserted into the connection port of the joint body. A packing compressed in the axial direction by the pressing tool constituting the flexible joint and the joint body is pressed into contact with the connection port and the resin pipe, and the resin pipe and the joint body are connected with the vicinity of the attachment point of the packing as a fulcrum. are connected to be able to swing relative to each other. Then, cast iron joint bodies and pressing tools are selected as the joint body and pressing tool, and the cylindrical core press-fitted into the place where the packing is attached to the resin pipe suppresses the diameter reduction deformation of the end of the resin pipe. That is what it is.

According to the connection structure with this configuration, since the cylindrical core is press-fitted into the place where the packing is attached to the resin pipe, the cylindrical core supports the resin pipe or the cylindrical core acts to increase the thickness of the resin pipe. At the point where the cylindrical core is press-fitted, the cylindrical core prevents the outer diameter of the resin pipe from decreasing, so there is a concern that the packing may not be compressed in the axial direction, and the watertightness of the packing may be impaired. It disappears.

In the present invention, the flexible joint is composed of the joint body having a flange around the opening of the connection port, and the ring-shaped pressing tool connected to the flange of the joint body using a fastener. According to this configuration, it is possible to use a flexible joint made of cast iron that is versatile, inexpensive, and has a simple configuration.

In the present invention, the cylindrical core is integrally provided with a flange portion that overlaps the end surface of the resin pipe, and the packing is provided between the flange portion of the cylindrical core and the stepped surface provided on the joint body. The interposed ring part and a thin cylindrical covering part that connects these packings and the ring part and covers from the outside the end of the resin pipe protruding from the place where the packing is attached are integrally provided, and It is possible to adopt a configuration in which a gap is formed between the cylindrical covering part and the inner circumferential surface of the connection port part. According to this, the ring part provided integrally with the packing helps prevent damage caused by collision between the brim part of the cylindrical core and the stepped surface provided on the joint body, and The covering portion serves to prevent damage caused by collision between the end of the resin pipe protruding from the attachment point of the packing and the inner circumferential surface of the connection port. The gap allows relative rocking between the resin pipe and the joint main body, with the vicinity of the attachment point of the packing serving as a fulcrum.

In the present invention, it is desirable that the outer circumferential surface of the cylindrical core forms a tapered surface that becomes smaller in diameter as it approaches the tip. According to this, it becomes easy to press-fit the cylindrical core into the place where the packing is attached to the resin pipe.

In the present invention, it is desirable that the inner circumferential surface of a predetermined region of the tip of the cylindrical core be formed into an outwardly expanding tapered surface so that the cylindrical wall of the cylindrical core is formed into a sharp point. If this configuration is adopted, there will be no step in the pipe near the tip of the cylindrical core that is press-fitted into the resin pipe, which could cause the accumulation of foreign matter. Even if it is left in place, there will be no adverse effects caused by the accumulation of foreign matter.

According to the present invention, even when a resin pipe is connected to a cast iron flexible joint, the outer diameter of the end of the resin pipe does not shrink due to the influence of heat, and insufficient compression of the packing in the axial direction occurs. Concerns and loss of watertightness due to packing are suppressed.

FIG. 1 is a cross-sectional view showing a connection structure between a resin pipe and a flexible joint according to an embodiment of the present invention. FIG. 2 is an enlarged view of the main part of FIG. It is a sectional view of a cylindrical core. FIG. 3 is a sectional view of a packing including a ring portion and a cylindrical covering portion. FIG. 7 is a cross-sectional view showing a connection structure between a resin pipe and a flexible joint according to another example. FIG. 2 is a cross-sectional view of the main parts showing a connection structure between a polypropylene resin pipe and a cast iron flexible joint used in a running water test.

FIG. 1 is a sectional view showing a connection structure between a resin pipe 200 and a flexible joint 100 according to an embodiment of the present invention, FIG. 2 is an enlarged view of the main part of FIG. 1, and FIG. 3 is a sectional view of a cylindrical core. FIG. 4 is a sectional view of the packing 30 including the ring portion 33 and the cylindrical covering portion 34. As shown in FIG.

The flexible joint 100 shown in FIG. 1 includes a joint main body 10 having a connection port 11 and a pressing tool 20 formed in a flange shape. A collar portion 12 is provided. Bolt insertion holes 14 and 21 are provided in the collar portion 12 and the pressing tool 20 at multiple locations equiangularly spaced in the circumferential direction, and the bolts 41 inserted into these bolt insertion holes 14 and 21 are A fastener 40 is constituted by a nut 42 screwed into.

The end of the resin pipe 200 with the packing 30 fitted thereon is inserted into the connection port 11 of the joint body 10. Further, a cylindrical core 50 is press-fitted into the entire end portion of the resin pipe 200 including the part of the resin pipe 200 where the packing 30 is attached. As shown in FIG. 3, the cylindrical core 50 has a flange-shaped portion 51 at the outer end. Further, the outer diameter D2 of the inner end (tip) of the cylindrical core 50 is slightly shorter than the outer diameter D1 of the outer end of the cylindrical core 50. Therefore, as illustrated in FIG. 3, the outer circumferential surface of the cylindrical core 50 is inclined by an inclination angle θ, and the outer circumferential surface of the cylindrical core 50 has a tapered surface whose diameter decreases as it approaches the tip. is forming. This cylindrical core 50 is press-fitted into the end of the resin pipe 200 before the end of the resin pipe 200 is inserted into the connection port 11 of the joint body 10. That is, the press-fitting operation of the cylindrical core 50 is carried out by inserting the tip of the cylindrical core 50 into the end of the resin pipe 200, and then hitting the flange-shaped portion 51 on the outer end side of the cylindrical core 50 with a hammer or the like to cut the entire length of the cylindrical core 50. The portion is press-fitted into the end of the resin pipe 200. At the same time, the flange portion 51 of the cylindrical core 50 is overlapped with the end surface of the resin tube 200 as shown in FIG.

When the cylindrical core 50 is press-fitted into the end of the resin pipe 200 in this way, the outer diameter of the end of the resin pipe 200 is reduced in diameter by the resin pipe supported by the cylindrical core 50 acting outward from the inside. This is suppressed by the effect of increasing the thickness of the resin tube 200 by the cylindrical core 50, or by the effect of increasing the thickness of the resin tube 200 by the cylindrical core 50 overlapping the resin tube 200 and increasing the apparent wall thickness of the resin tube 200. For the cylindrical core 50, it is possible to use a resin made of the same material as the resin tube 200, or a resin that has better heat resistance and rigidity than the resin tube. Further, as the material of the cylindrical core 50, it is also possible to use stainless steel, which has excellent rust resistance and heat deformation resistance. The wall thickness of the cylindrical core 50 is desirably as thin as possible in consideration of heat deformation resistance. This is because in a drainage piping system, if there is a level difference in the pipe line, the level difference becomes a trigger for the accumulation of foreign substances. Therefore, as shown in a partially enlarged view in FIG. 1, by forming the inner circumferential surface of the constant region L at the tip end of the cylindrical core 50 into an outwardly expanding tapered surface 52, the cylindrical wall of the cylindrical core 50 is It is desirable to form it into a sharp point. By doing so, the inner circumferential surface 201 of the resin tube 200 and the inner circumferential surface 53 of the cylindrical core 50 are continuous without forming a step through the tapered surface 52, so that the step becomes a trigger for contaminants to accumulate. This has the advantage that this will no longer be the case. Adopting this configuration is particularly advantageous when the cylindrical core 50 is made of a resin made of the same material as the resin tube 200 or a resin that has better heat resistance and rigidity than the resin tube. This is because when resin is used for the cylindrical core 50, the wall thickness of the cylindrical core 50 must be made relatively thick in order to avoid the diameter of the cylindrical core 50 itself from shrinking due to the influence of heat, etc. Even in such a case, the inner circumferential surface 201 of the resin tube 200 and the inner circumferential surface 53 of the cylindrical core 50 are continuous without forming a step through the tapered surface 52. It depends on becoming. It is sufficient that the axial length of the tapered surface 52 formed in the fixed region L of the distal end of the cylindrical core 50 is, for example, about 15 mm. On the other hand, if stainless steel, which has excellent rust resistance and heat deformation resistance, is used as the material for the cylindrical core 50, the stainless steel cylindrical core 50 itself will not shrink in diameter due to the influence of heat. It is desirable to set the wall thickness of the cylindrical core 50 to about 1.2 mm or less on the premise that it satisfies the minimum required strength. is suppressed to a minimum, making it difficult for contaminants to accumulate. Therefore, in this case, it is not necessarily necessary to form the inner circumferential surface of the constant region L of the distal end portion of the stainless steel cylindrical core 50 into an outwardly expanding tapered surface 52. FIG. 5 shows an example in which a cylindrical core 50 made of stainless steel is used and the tapered surface 52 shown in FIG. 1 is omitted. In FIG. 5, elements that are the same as or correspond to those shown in FIG. 1 are given the same reference numerals, and detailed description thereof will be omitted.

As shown in FIG. 4, the packing 30 is formed into a thick trapezoidal cross section with a constant axial length, one end surface is formed as a vertical surface 31, and the other end surface is an inclined surface. 32. This packing 30 is integrally provided with a ring portion 33 and a thin cylindrical covering portion 34. More specifically, the packing 30 and the ring part 33 are integrally connected by a thin cylindrical covering part 34 extending from the inner peripheral part of the packing 30 on the inclined surface 32 side. Then, prior to inserting the end of the resin pipe 200 into the connection port 11 of the joint body 10, the packing 30 is fitted onto the end of the resin pipe 200, and a thin cylindrical covering is provided. The ring portion 33 is superimposed on the brim portion 51 of the cylindrical core 50 described above by causing the end portion of the resin pipe 200 protruding from the attachment location of the packing 30 to be covered from the outside by the portion 34 .

As shown in FIG. 1 or 2, the connection port 11 of the joint body 10 into which the end of the resin pipe 200 is inserted and the pressing tool 20 fitted onto the end of the resin pipe 200 have an axial direction. An inclined surface 15 and a vertical surface 22 facing each other are separately provided. The packing 30 attached to the end of the resin pipe 200 inserted into the connection port 11 of the joint body 10 is sandwiched between the inclined surface 15 and the vertical surface 22 in the axial direction. Further, the ring portion 33 integrated with the packing 30 is interposed between the flange portion 51 of the cylindrical core 50 and the vertical stepped surface 16 provided on the joint body 10.

When the bolt 41 and nut 42 as the fastener 40 shown in FIG. As a result, the packing 30 comes into pressure contact with the connection port 11 and the resin pipe 200, thereby exhibiting watertightness. Further, as shown in FIG. 2, a gap S is formed between the cylindrical covering part 34 that covers the end of the resin pipe 200 protruding from the attachment point of the packing 30 from the outside and the inner circumferential surface 13 of the connection port part 11. has been done. Therefore, due to the elasticity of the packing or the gap S, bendability is imparted to the connection point between the resin pipe 200 and the flexible joint 100, with the vicinity of the attachment point of the packing 30 as a fulcrum, and based on this bendability, The resin pipe 200 and the joint body 10 are relatively movable.

Further, a ring portion 33 integral with the packing 30 is interposed between the stepped surface 16 of the connection port portion 11 and the flange portion 51 of the cylindrical core 50. Therefore, a situation in which foreign matter enters the gap S from the gap between the stepped surface 16 of the connection port 11 and the flange portion 51 of the cylindrical core 50 and accumulates therein becomes less likely to occur. This helps in making the bendability at the connection point between the resin pipe 200 and the flexible joint 100 less likely to be impaired over a long period of time.

In this embodiment, the joint body 10 and the pressing tool 20 that constitute the flexible joint 100 are made of cast iron, and the resin pipe 200 is made of polypropylene. For this reason, compared to the case of using the heat fusion type joint explained at the beginning, the configuration is simpler, the connection work does not require as much skill, and the work time required for connection is shortened. There are advantages.

Further, since the cylindrical core 50 is press-fitted into the resin pipe 200 at the location where the packing 30 is attached, the cylindrical core 50 prevents the outer diameter of the resin pipe 200 from decreasing at the press-fitted location. Therefore, there is no fear of insufficient compression of the packing 30 in the axial direction, and there is no possibility that the watertightness of the packing 30 will be impaired.

The connection structure between a resin pipe and a flexible joint according to the present invention can be applied to various types of flexible joints made of cast iron, such as socket type, Y-shape, and cross-shape.

10 Joint body 11 Connection port 12 Flange 16 Stepped surface 20 Pressing tool 30 Packing 33 Ring portion 34 Cylindrical covering portion 40 Fastener 50 Cylindrical core 51 Flange portion 52 Tapered surface expanding outward 100 Flexible joint 200 Resin Tube L Fixed area at the tip of the cylindrical core S Gap

Claims (5)

The end of the resin pipe on which the packing is fitted is inserted into the connection port of the joint body, and is pushed in the axial direction by the joint body and the pressing tool that cooperates with the joint body to form a flexible joint. A compressed packing is pressed into contact with the connection port and the resin pipe, and the resin pipe and the fitting body are connected so as to be able to swing relative to each other using the vicinity of the attachment point of the packing as a fulcrum. A connection structure with a flexible joint,
The fitting body and pressing tool are made of cast iron, and the cylindrical core press-fitted into the part of the resin pipe where the packing is attached suppresses diametric deformation at the end of the resin pipe. Connection structure between resin pipe and flexible joint. Claim 1: The flexible joint comprises the joint main body having a flange around the opening of the connection port, and the ring-shaped pressing tool connected to the flange of the joint main body using a fastener. Connection structure between resin pipe and flexible joint described in . The cylindrical core is integrally equipped with a flange portion that overlaps the end surface of the resin tube,
The packing includes a ring portion interposed between the brim portion of the cylindrical core and a stepped surface provided on the joint body, and a ring portion that connects these packings and the ring portion and protrudes from the mounting location of the packing. A thin cylindrical covering part that covers the end of the resin pipe from the outside is integrally provided, and a gap is formed between the cylindrical covering part and the inner circumferential surface of the connection port part. A connection structure between a resin pipe and a flexible joint according to claim 1 or 2. 4. The connection structure between a resin pipe and a flexible joint according to claim 3, wherein the outer circumferential surface of the cylindrical core forms a tapered surface whose diameter decreases as it approaches the tip. The resin pipe and flexible resin pipe according to claim 3, wherein the inner circumferential surface of a predetermined region at the tip of the cylindrical core is formed into an outwardly expanding tapered surface so that the cylindrical wall of the cylindrical core is formed into an acute shape. Connection structure with fittings.

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