JPH0342301Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention relates to expansion pipe joints, and more specifically, it is mainly used for pipe joints made of heat-resistant thermoplastic resin, and is used to prevent thermal expansion and contraction of pipes. This invention relates to an expansion pipe joint suitable for absorbing water.

[Conventional technology]

Expansion pipe joints are conventionally used to connect to pipelines and are designed to absorb the stress caused by the pipe's axial expansion and contraction caused mainly by changes in the temperature of the fluid being transported, thereby preventing the pipe from deforming or breaking. Various proposals have been made.

As a result of extensive research, the applicant has developed an expansion pipe joint that has higher practical value than these conventionally used expansion joints, and has already applied for utility model registration (Utility Model No. 30787/1987). (see official bulletin).

The expansion pipe joint according to the above utility model registration application has a structure in which a sliding end connector is slid into a sealing socket provided in the pipe joint body, and mainly plastic pipes are connected to both ends of the joint. The stress caused by the thermal expansion of the pipe or the shrinkage stress associated with it is absorbed by the pipe fitting body or slide end connector that slides into each other, thereby preventing pipe deformation or breakage, and improving the safety of piping system design. This increases the strength of the pipe and enables long-term use of the pipe.

[Problem to be solved by the invention] However, in the expansion pipe joint related to the above-mentioned utility model registration application, the seal between the pipe joint body and the slide end connector is the same as the seal socket of the pipe joint body and the slide end connector. This is done between the sliding parts of the end connector by an O-ring (usually made of a rubber elastic material) that is fitted into an annular groove provided on the outer periphery of the sliding part. When made of polyvinylidene fluoride resin (hereinafter abbreviated as PVDF) or polypropylene resin (hereinafter abbreviated as PP), which have excellent heat resistance, these plastics have the property of having a high heat distortion temperature but a high expansion coefficient. Therefore, if the temperature drops to room temperature after transporting high-temperature fluid, the gap between the two may become larger than the sealing dimension of the O-ring, resulting in the problem of fluid leaking out of the piping system. I found out something.

The present invention solves these problems, absorbs stress caused by thermal expansion and contraction of the pipes connected to both ends of the pipe joint more smoothly than before, and maintains excellent sealing performance over a long period of time. The purpose is to provide an expansion pipe joint that can be held in place.

[Means for solving problems]

The structure of the present invention as a means for solving the above problems will be explained with reference to FIG. 1, which corresponds to an embodiment of the present invention. is the pipe joint body 1,
A slide end connector 2, a sealing member consisting of a fluorine resin expansion ring 16, a fluorine resin V-shaped packing 17, a metal spring 19, and a fluorine resin gland 3, and a body cap 4.
It is composed of a large bag nut 5 and a small bag nut 6. The pipe joint body 1 has a flow passage 7 and a seal socket 8 whose diameter is larger than the inner diameter of the flow passage 7, and the slide end connector 2 has a flow passage 11 therein. and has a slide portion 12 that slides into the flow path inner circumferential surface 9 of the pipe joint body 1,
The sealing member includes a fluorine resin expansion ring 16 that is fitted into an annular space 15 formed between the outer circumferential surface of the slide portion 12 and the inner circumferential surface of the sealing socket portion 8 and arranged in alignment. , a V-shaped packing 17 made of fluorine resin, a metal spring 19, and a gland 3 made of fluorine resin.The body cap 4 is in contact with the end surface of the pipe joint body 1 via an O-ring 21, and a large bag nut 5 and a small bag nut are connected to each other. 6 are screwed onto each end of the pipe joint body 1, and are connected to the slide end connector 2 and the gland 3 by the large nut 5.
However, the body cap 4 is also attached by the pouch nut 6.
are each fixed to the pipe joint body 1.

[Effect]

In the present invention having the above configuration, when the pipe connected to the slide end connector 2 expands in its axial direction due to a rise in temperature, the slide end connector 2 connects the slide portion 12 to the pipe joint. While being inscribed in the flow path inner peripheral surface 9 of the main body 1, it slides into the inside of the pipe joint main body 1 by the amount of thermal expansion of the pipe, and the stress is absorbed by the thermal expansion of the pipe. Furthermore, when the pipe connected to the body cap 4 experiences thermal expansion in the same way as described above, the body cap 4 transmits the stress due to the pipe's thermal expansion to the pipe fitting body 1, and moves the pipe fitting body 1 toward the sliding end connector 2 side. push it away. The pipe joint main body 1 subjected to such stress slides while circumscribing the inner circumferential surface 9 of the flow path to the slide portion 12 of the slide end connector 2. In other words, the pipe joint body 1 slides into the pouch while the slide portion 12 is fitted inward. The nut 6 is moved to the slide end connector 2 side with the nut 6 attached to absorb this stress.

On the other hand, when the pipes at both ends contract due to a drop in temperature, the shrinkage stress is absorbed by the opposite action to that described above.

Further, the sealing member fitted into the annular space 15 between the sealing socket part 8 of the pipe joint body 1 and the sliding part 12 of the sliding end connector 2 is made of metal pressed by the fluorine resin gland 3. The V-shaped packing 17 made of fluorine resin, to which a constant load is elastically applied by the spring 19 made of fluorine resin, is constantly pushed open by the expansion ring 16 made of fluorine resin, so that the sealing socket part 8 and the sliding part 12 at the same time with high sealing pressure, so even if spatial distortion occurs between them due to thermal expansion and contraction of the pipe fitting body 1 and slide end connector 2, it is always absorbed and high sealing performance is maintained for a long period of time. It has the effect of holding for a long time.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a longitudinal sectional view of an embodiment of the expansion pipe joint of the present invention, showing the expansion pipe joint placed in a pipe. The material that makes up the expansion joint is
It is made of a heat-resistant thermoplastic resin such as PVDF or PP. Especially when used in a pure water transport line, it is preferable to use one that has high heat resistance and has few components leached into the fluid.

In the figure, 1 is a pipe joint body,
It is formed into a hollow cylindrical shape by PVDF, and its end surface 1
An internal flow path 7 is opened at the end face, and a sealing socket 8 connected to the flow path 7 is opened at the other end face.
This sealing socket 8 has a diameter larger than the inner diameter of the flow path 7, and forms a space in which a sealing member, which will be described later, is mounted.

2 is the slide end connector,
A slide part 12 made of PVDF and having a flow passage 11 whose inner diameter is the same as the opening in the end face 10 of the pipe joint body 1, and a socket part for connecting a pipe (indicated by a dotted line) following the flow passage 11. It consists of 13. The inner part of this slide part 12 is slidably fitted into the inner circumferential surface 9 of the flow path 7 of the pipe joint body 1, and this inner part and inner circumferential surface 9 are connected to the pipe connected to the socket part 13. The slide end connector 2 is fitted with a sliding margin that absorbs the expansion of the slide end connector 2.Furthermore, on the outer periphery of the slide end connector 2, following the slide portion 12, there is a flange portion having an outer diameter slightly larger than the inner diameter of the sealing socket portion 8. 14 is provided, and is engaged with the flange 25 of the large bag nut 5 and fixed to the pipe joint body 1.

16 is an expansion ring, 17 is a V-shaped packing,
18 is a washer, 19 is a disc spring, and 3 is a gland, and these elements constitute a sealing member. These elements are arranged in the annular space 15 formed between the inner circumferential surface of the sealing socket part 8 and the outer circumferential surface of the slide part 12 in the above order from the back. (See Figure 3).

The expansion ring 16 is made of polytetrafluoroethylene (hereinafter abbreviated as PTFE), and its cross-sectional shape is a rectangular shape with four notched corners.
The extended portions at both ends of the two end portions are fitted together.

The V-shaped packing 17 is made of PTFE, and three pieces are used in a row. Expansion ring 16 and V
The material of the mold packing 17 is not limited to PTFE,
Other fluorine resins may also be used.

The disc spring 19 is made of metal, contacts the V-shaped packing 17 via the washer 18, and has the function of elastically pressing the V-shaped packing 17. Note that the effect is the same even if a coil spring is used instead of the disk spring 19, and any spring that has a spring action may be used.

The gland 3 is made of PVDF, and the outer diameter of the flange 20 provided at one end thereof is smaller than the outer diameter of the pipe fitting body 1.
The expansion ring 16, the V-shaped packing 17, the washer 18, and the disc spring 19 are expanded by engaging the shoulder portion 26 of the large bag nut 5. It's pressing.

Note that the material of the ground is not limited to PVDF, and may be other fluorocarbon resins.

The seal member has the above structure,
The disc spring 19 pressed by the ground 3 is
Since its original elastic force acts to always apply a constant load to the V-shaped packing 17 via the washer 18, high sealing performance can always be obtained without being affected by thermal expansion or contraction.

4 is a body cap made of PVDF, which contacts the pipe fitting main body 1 through an O-ring 21 fitted into an annular groove on the end face 10, and has a flow having the same diameter as the opening of the pipe fitting main body on the end face 10. It has a channel 22 and a socket 23 for pipe connection following the channel 22. Further, the inner end of the body cap 4 is provided with a flange 24 having an outer diameter slightly smaller than the outer diameter of the pipe joint body 1, and is engaged with the flange 27 of the pouch nut 6 to be fixed to the pipe joint body 1. has been done.

5 is a large bag nut made of PVDF, which has a flange 25 on the outer end and a shoulder 26 on the inside, the flange 25 is engaged with the flange 14 of the slide end connector 2, and the shoulder 26 is By engaging the flange 20 of the gland 3 and screwing its inner end to the outer periphery of the pipe joint body 1, the sliding end connector 2 is assembled.
and a gland 3 are fixed to the pipe joint body 1.

6 is a pouch nut made of PVDF, and by engaging the flange 27 provided at the outer end with the flange 24 of the body cap 4 and screwing the inner end onto the outer periphery of the pipe joint body 1, the body cap can be assembled. 4 is fixed to the pipe joint body 1.

According to this embodiment configured as described above, the pipe connected to the slide end connector 2 or the body cap 4 is heated to a temperature caused by an increase in the temperature of the fluid or the air temperature, or particularly by steam transport for sterilization in the pure water line. When the tube joint body 1 expands in the axial direction due to rising or the like, the tube joint body 1 and the slide end connector 2 slide relative to each other to absorb the stress caused by this thermal expansion, as shown in FIG. Furthermore, even if the pipe contracts due to a drop in temperature, the stress caused by the contraction is absorbed by moving in the opposite direction.

Further, the sealing member installed in the annular space 15 is a V-shaped packing 17 that is pressed by the disc spring 19.
In the state in which the sealing member 8 is expanded by the expansion ring 16, it simultaneously contacts the sealing socket part 8 and the slide part 12 with high sealing pressure, and maintains high sealing performance between them for a long period of time.

[Effect of idea]

As described above, according to the present invention, even if the pipe connected to the expansion joint generates stress due to thermal expansion and contraction, the pipe joint main body and the slide end connector mutually slide to overcome the stress. , it prevents curved deformation of pipes, increases the design safety of piping systems, and enables long-term use of pipes. In addition, the sealing member prevents thermal expansion of the pipe fitting body and slide end connector due to temperature changes.
Since it always acts to absorb spatial distortion caused by shrinkage, high sealing performance is maintained over a long period of time.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal cross-sectional view showing a state in which a pipe is attached to an embodiment of the present invention, Fig. 2 is a longitudinal cross-sectional view showing a state in which stress is applied due to thermal expansion of the pipe in Fig. FIG. 2 is an enlarged vertical cross-sectional view of the sealing member shown in FIG. 1; 1... Pipe joint body, 2... Slide end connector, 3... Gland, 4... Body cap, 5... Large bag nut, 6... Small bag nut, 7,
11... Channel, 8... Seal socket, 12...
Slide part, 16...Expansion ring, 17...V
Type packing, 18...Washer, 19...Disc spring.

Claims (1)

[Scope of utility model registration request] A pipe joint body 1 has a flow passage 7 and a sealing socket 8 whose diameter is larger than the inner diameter of the flow passage 7 in succession, and a pipe joint body 1 has a flow passage 11 therein and has a flow passage 7 therein. a slide end connector 2 having a slide portion 12 that slides into the inner circumferential surface 9;
An expansion ring 1 made of fluorine resin is aligned in an annular space 15 formed between the outer circumferential surface of the slide portion 12 and the inner circumferential surface of the sealing socket portion 8.
6. A sealing member consisting of a V-shaped packing 17 made of fluorine resin, a metal spring 19 and a gland 3 made of fluorine resin; a body cap 4 that contacts the end surface of the pipe joint body 1 via an O-ring 21; By screwing onto the outer peripheral surface of the joint body 1, the slide end connector 2 and the gland 3
and a large bag nut 5 and a small bag nut 6 for fixing the body cap 4 to the pipe joint body 1, respectively.