JPH04357387A - Pipe connection structure - Google Patents

Abstract

PURPOSE:To improve the adhesive strength of a pipe joint by effectively using the inside of a faucet on the side of a pipe inserting end in the pipe joint or a pipe with the faucet as an adhering face. CONSTITUTION:In a faucet 1a having a tapered inside where a pipe 100 is inserted and adheres, at least an inside part 3a in a faucet inserting part 3 is formed of an elastic material from a pipe inserting end to a position where its inside diameter becomes about equal to the outside diameter of the pipe 100. A specified adhesive used for adhesion to the pipe 100 is applied to the above elastic material, whose applied face is thereby swelled and dissolved.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to improvements in the structure of pipe joints and socket-equipped pipes used to connect plastic pipes such as polyvinyl chloride pipes and chlorinated polyvinyl chloride pipes.

0002

[Prior Art] For example, when installing polyvinyl chloride pipes (hereinafter referred to as PVC pipes) for water supply, a plastic pipe called a TS joint or a TS pipe with a socket, which has a tapered inner surface of the socket, is used. A pipe fitting or a pipe with a socket is used (see, for example, JIS K6743, K6777).

This type of pipe joint or pipe with a socket (hereinafter simply referred to as a "pipe joint" in this "Prior Art" section) is a pipe joint connected to the pipe joint A, as shown in FIG. B
Considering that there is a variation or tolerance of ±α in the standard outer diameter D, the inner diameter d1 of the inlet part of the joint socket is
is set to be greater than D + α + β (β is the tolerance of the joint), and the inner diameter d2 at the back of the socket is set to be less than D - α - β, so that the inner surface of the socket has a predetermined taper. be.

[0004] A method for connecting pipes using such pipe joints is the TS method (Taper sized solvent welding method).
(abbreviation for lvent welding method). As shown in FIG. 14, this can be done by applying a predetermined adhesive to the inner surface A1 of the socket of the pipe fitting A and the outer surface B1 of the pipe B inserted into the socket. The resin is swollen and dissolved, and in this state, the tube B is inserted into the socket and the two are joined as shown in FIG. According to this, the pipe fitting A and the pipe B can be easily connected at room temperature without heating the pipe connecting portion, etc., so piping can be easily performed in cold regions or places where open flames are strictly prohibited.

[0005]

However, the above-mentioned pipe joints or pipes with sockets have the following problems. That is, to explain a pipe joint as an example, as shown in FIG. 16, when the melting margin of the adhesive on the outer surface of pipe B and the inner surface of the socket of joint A are respectively Δt and Δt', If tube B is inserted without adhesive, the tube end position will be at point O1, but with adhesive applied, tube B can be inserted even deeper due to the melting of the surface layer. The end position is point O2 located further back than point O1. When the tube B is further pushed in from this state, the insertion force f changes the tube B and the joint socket, and the tube end position in the molten layer changes from point O2' to point O3'.
Move to.

As a result, the pipe B and the joint A are bonded to each other in the range from point O1 to point O3, and the bond length to obtain bond strength is the range l from point O1 to point O3. The range l' from point O1 to the opening end (point R) of the joint socket, excluding that part, becomes a gap S where the pipe and the joint are not bonded to each other, and cannot contribute to bonding. In the case of conventional pipe joints, the bonding length l at this time is, for example, approximately (1/2) to (1/3) of the total length of the joint socket.
It is said that Moreover, in this case, since the insertion force f, the degree of insertion, the amount of adhesive applied, etc. when inserting the pipe B into the joint socket differ depending on the operator, variations in adhesive strength are likely to occur. Therefore, poor adhesion or poor connection is likely to occur, but if such a poor connection occurs, the pipe B may slip out of the joint socket and a large amount of water may leak.

[0007] Regarding conventional pipe fittings or pipes with sockets having tapered inner surfaces of the sockets, it is necessary to effectively utilize the entire length of the socket in the joint or pipe with sockets when joining the pipe. As a result, the actual situation was that adhesive strength was likely to be insufficient or inconsistent, and there was even the possibility of large amounts of water leaking due to poor connections. In order to improve the adhesive strength, it is possible to increase the amount of tube insertion by using a joint with a long socket or a pipe with a socket, but this is uneconomical since the amount of material consumed increases accordingly.

The present invention has been made in view of the above-mentioned conventional circumstances, and in a pipe connection structure of a pipe joint or a pipe with a socket, in which the inner surface of the socket is formed into a tapered shape, the pipe is connected to the socket. By making sure that no space is created between the inner surface of the socket and the pipe when inserting and joining the joint, the length of the socket can be effectively used as the bonding length, thereby making it possible to bond the joint or socket. It is an object of the present invention to improve adhesive strength without increasing the total length of an attached tube.

[0009]

[Means for Solving the Problems] To achieve the above object, the present invention provides that the inner diameter of the pipe insertion end of the socket is larger than the outer diameter of the pipe inserted into the socket, and the inner diameter of the inner part of the socket is larger than the outer diameter of the pipe inserted into the socket. In a pipe connection structure in which the inner surface of the socket is tapered to be smaller than the outer diameter of the pipe, and the inner surface of the socket is coated with an adhesive and then joined to the pipe, the socket is connected to the pipe. The present invention is characterized in that at least the inner surface side portion of the socket insertion portion from the tube insertion end to the position where the inner diameter is approximately equal to the outer diameter of the tube is made of an elastic body having a predetermined elasticity.

0010

[Operation] According to the above structure, the adhesive strength to the pipe can be improved in the following manner. That is, when an adhesive is applied to predetermined areas of the inner surface of the socket and the outer surface of the pipe fitting or socket-equipped pipe to be joined, the adhesive swells and dissolves the applied surface. At this time, the inner surface layer of the elastic body constituting the inner surface of the socket insertion portion from the tube insertion end to the position where the inner diameter is approximately equal to the outer diameter of the tube is also swollen by the adhesive. be dissolved.

[0011] Next, when the pipe is inserted into the socket of the joint or pipe with a socket in this state, the molten surface layer on the inner surface of the socket and the outer surface of the pipe adhere, but the inner surface of the socket becomes tapered. Therefore, in that state, the tube insertion end side, that is, the open end side of the inner surface of the socket remains in a state where it is not bonded to the tube. However, in the above pipe connection structure, at least the inner surface side portion of the socket insertion part from the pipe insertion end to the position where the inner diameter is approximately equal to the outer diameter of the pipe is made of an elastic body having a predetermined elasticity. and the inner surface layer is also dissolved by the adhesive as mentioned above,
When an external force is applied from the outer surface of the socket insertion part, the inner surface thereof is relatively easily reduced in diameter and comes into contact with the outer surface of the tube inside the socket. As a result, the inner surface of the socket on the tube insertion side, which would not be bonded simply by inserting the pipe into the joint or the socket of the pipe with a socket, is also bonded to the outer surface of the pipe within the socket. Thereby, the inner surface of the socket on the tube insertion end side of the pipe fitting or socket-equipped pipe can also be effectively used as an adhesive surface, and the adhesive strength can be improved by that much compared to the conventional one.

0012

[Examples] Examples of the present invention will be described below. This embodiment relates to a case in which the present invention is applied to a band type pipe joint. As shown in FIG. , socket insertion parts 3, 3 disposed on both sides thereof and integrated with the main body 2 by, for example, integral molding or adhesion, and tightening bands 4 attached to the outer periphery of each socket insertion part 3, 3, respectively. , 4. Then, the socket 1a is connected to the both sides 2b, 2b of the joint body 2 and the socket insertion parts 3, 3.
1a, and the inner surface of each socket 1a is formed into a predetermined tapered shape.

Here, if the standard outer diameter of the pipe (PVC pipe in this embodiment) 100 connected to this pipe joint 1 is D, and its tolerance is ±α, then the inlet portion of the socket 1a, that is, the socket insertion The inner diameter d1 of the open end of section 3 is D+α+β (β is the diameter of pipe fitting 1
The inner diameter d2 of the back of the socket, that is, the tapered end of the joint body 2, is D-α-β.
The dimensions are said to be equal to or smaller than.

In this pipe joint 1, as a feature of the present invention, each of the socket insertion parts 3 is made of an elastic body having a predetermined elasticity, and the pipe 100 is inserted from the pipe insertion end thereof. The inner surface portion up to a position having an inner diameter approximately equal to the outer diameter D of the socket is a socket taper portion 3a. In other words, when the pipe 100 is inserted into the pipe fitting 1 by a predetermined amount for joining, the taper part in the range that does not contact the outer surface of the pipe 100 at all or only slightly contacts the outer surface of the pipe 100 is made of an elastic material. It is designated as part 3a. When a predetermined adhesive used for joining the joint 1 and the pipe 100 is applied to the elastic body constituting the socket taper part 3a, that is, the socket insertion part 3, the applied surface is coated with the adhesive. It is designed to swell and dissolve.

According to the pipe joint 1 having such a structure, the adhesive strength to the pipe 100 can be improved in the following manner. That is, as shown in an enlarged view in FIG. 2, when adhesive is applied to a predetermined range of the inner surface of the socket of the pipe joint 1 to be joined and the outer surface of the pipe 100, the adhesive coats the applied surface, that is, the inner surface of the socket and the pipe. Each of the outer surface layers 1b and 100a swells and dissolves. At this time, the inner surface layer 3a' of the elastic body forming each socket taper part 3a from the tube insertion end to the position where the inner diameter is approximately equal to the outer diameter D of the tube 100 is also swollen and dissolved by the adhesive. Ru.

Next, in this state, insert the pipe 10 into the joint socket 1a.
When 0 is inserted, the above melted surface layers 1b and 100a
However, since the inner surface of the socket is tapered, the tube insertion side of the inner surface of the socket, that is, the taper part 3a of the socket remains in a state where it is not bonded to the pipe 100. However, in this pipe joint 1, the socket insertion part 3 that constitutes the socket taper part 3a on the inner surface side is made of an elastic body having a predetermined elasticity, and the inner surface layer 3a' is also adhesively bonded as described above. Since it is dissolved by the agent, when an external force F is applied from the outer surface side of the socket insertion part 3 as shown in FIG. 2, the diameter is reduced relatively easily and it comes into contact with the outer surface of the tube inside the socket 1a. As a result, as shown in FIG. 3, the socket tapered part 3a on the inner surface side of the socket insertion part 3, which is not bonded only by inserting the pipe 100 into the joint socket 1a, is also bonded to the outer surface layer 100a of the pipe 100. It turns out.

[0017] Thereby, the inner surface of the socket on the pipe insertion side of the pipe joint 1 can be effectively used as an adhesive surface, and the adhesive strength can be improved by that much compared to the conventional one. Therefore, even if the overall length of the joint socket 1a is shorter than that of a conventional pipe joint, the same adhesive strength can be ensured, and the material can be saved accordingly.

In the above embodiment, a tightening band 4 is attached to the outer periphery of each socket insertion part 3 and tightened to reduce the diameter of the socket insertion part 3, but a second embodiment shown in FIG. Like the pipe joint 11 shown in FIG.
The elastic body 13a may have a reduced diameter. In this pipe joint 11, unlike the case of the first embodiment, the socket insertion parts 13, 13 are not entirely made of an elastic body, but the outer part thereof is made of the joint body 12, Only the inner side portions 13a, 13a are made of an elastic body.

In this case, the material of the inner surface side portion 13a of each socket insertion portion 13 should be made of hard vinyl chloride or the like, and the shape should be a C-ring (when the diameter of the ring is reduced until there is no gap, the inner diameter of the ring is (the outer diameter of the tube may be smaller than the outer diameter of the tube). In this case, it is particularly preferable to use the same material as the pipe because a large adhesive force can be obtained with the pipe connecting adhesive. The diameter of the C-ring is reduced by screwing in the cap nut, and the C-ring is brought into close contact with the pipe and bonded to the pipe.

Furthermore, the cross-sectional shape of the C-ring is, for example, as shown in FIG.
- The one shown in FIG. 7 may also be used. Among these, the C-ring 13c1 in FIG. 5 has one end tapered on the outer diameter side, the C-ring 13c2 in FIG. 6 has one end tapered from the outer diameter side to the inner diameter side, and the C-ring 13c2 in FIG. The C ring 13c3 has a cylindrical shape. Here, the above-mentioned elastic body includes elastic plastic (e.g. vinyl chloride),
Examples include elastomers (eg, vinyl chloride elastomer), rubber materials (eg, chloroprene rubber), and the like. Also, if the material is hard, use a C ring.

Further, the shape of the socket insertion portion on the inner surface of the joint socket is not limited to the shape shown in each of the above embodiments, but may be, for example, as shown in FIGS. 8 to 10. Of these, FIG. 8 shows a case in which only the inner surface of the joint body 22 is tapered and the inner diameter of the socket insertion part 23 made of an elastic body is a constant diameter, and FIG. Each inner surface is tapered, but the latter taper is a two-step taper with a gentler slope than the former taper, and the one shown in FIG. 43b is formed.

On the other hand, FIG. 11 shows a pipe with a socket 51 according to a third embodiment of the present invention, and shows an example in which the same structure as the socket insertion part shown in FIG. 4 is applied to one end. It is. The inner surface side portion 5 of the socket insertion part 53 in this socket-equipped pipe 51
The structure and function of the cap nut 3a, the cap nut 54, etc. are the same as in the case of the pipe joint 11 shown in FIG. Similarly, in other embodiments, the structure adopted for the pipe joint can be applied to the pipe with a socket.

The socket of this type of socket-equipped pipe can be manufactured by, for example, making a socket separately and fusing it to the end of the pipe, as shown in the example shown in FIG. In addition, as another method, for example, as shown in FIG. 12, a socket 61 having a tube slip-out prevention mechanism 64 only in one socket 61a is used, and the other socket 61a (the one without the tube pull-out prevention mechanism 64) is used. By firmly connecting (gluing) ' to the end of the pipe at a factory, etc., rather than at the site,
It is also possible to produce a tube 71 with one side support. Furthermore, by attaching sockets 61 as described above to both ends of the tube, it is also possible to produce a tube with dual receivers. In such a factory-installed pipe with a socket, the other (pipe slippage prevention mechanism 64)
Since the connection work on the socket 61a' side (the one without) is performed in a factory, there is no possibility of defective construction.
For the 1a' side, the conventional connection method is sufficient.

[0024] The pipe joints to which the present invention is applied are as follows:
Not limited to sockets as shown in Figures 1 and 4, elbows,
It may be bend, cheese, etc.

[0025]

As described above, according to the present invention, the inner surface of the socket into which the tube is inserted is formed into a tapered shape, and the inner surface of the socket is coated with an adhesive before being inserted into the socket. In the pipe connection structure to be joined, at least the inner surface side portion of the socket insertion portion having an inner diameter substantially equal to or larger than the outer diameter of the pipe is made of an elastic body having a predetermined elasticity. , the inner surface of the socket on the tube insertion side can be effectively used as an adhesive surface.

[0026] Therefore, the adhesive strength can be improved by that much more than the conventional one. In other words, the length of the socket, that is, the length of the joint or the length of the pipe with a socket, is shorter than that of a conventional pipe joint or pipe with a socket to obtain a given adhesive strength, and the material consumption is reduced accordingly. This means that you will need less.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway front view showing a state in which a pipe joint according to a first embodiment of the present invention is used.

FIG. 2 is a partially enlarged cross-sectional view showing a state immediately after the pipe is inserted into the pipe joint.

FIG. 3 is a partially enlarged sectional view showing a state in which a pipe is inserted into the pipe joint and the socket insertion portion is reduced in diameter.

FIG. 4 is a partially cutaway front view showing the state in which the pipe joint according to the second embodiment of the present invention is used.

FIG. 5 is a sectional view showing another example of the shape of the elastic body (C ring) that can be used in the present invention.

FIG. 6 is a sectional view showing an example of another type of elastic body (C ring).

FIG. 7 is a sectional view showing still another example of the elastic body (C ring).

FIG. 8 is a sectional view of a main part showing another structural example of a joint socket that can be employed in the present invention.

FIG. 9 is a sectional view of a main part showing a structural example of another type of joint socket.

FIG. 10 is a sectional view of a main part showing still another structural example of the joint socket.

FIG. 11 is a partially cutaway front view of a pipe with a socket according to a third embodiment of the present invention.

FIG. 12 is a partially cutaway front view of a pipe with a socket (factory-installed pipe with a socket) according to a fourth embodiment of the present invention.

FIG. 13 is a cross-sectional view showing the dimensional relationship between the conventional pipe joint and the pipe, which is used to explain the problems of the conventional pipe joint.

FIG. 14 is a partial sectional view showing a state in which a pipe is inserted into the joint.

FIG. 15 is a partial sectional view showing a state in which the joint and the pipe are joined.

FIG. 16 is a partial cross-sectional view showing changes in the tube end position due to tube insertion after adhesive application.

[Explanation of symbols]

1, 11... Pipe joint, 1a, 61a... Socket, 2, 12, 22, 32... Joint body, 3, 13, 23
, 33, 43, 53... socket insertion part, 3a, 13a,
53a...Inner side portion (3a...Socket tapered part), 51, 71...Pipe with socket, 100...Pipe, d1...Inner diameter of the pipe insertion end of the socket, d2. ...Inner diameter of the back of the socket, D...Outer diameter of the pipe.

Claims (1)

[Claims] Claim 1: The inner surface of the socket is such that the inner diameter of the pipe insertion end of the socket is larger than the outer diameter of the pipe inserted into the socket, and the inner diameter of the inner part of the socket is smaller than the outer diameter of the pipe. is formed into a tapered shape, and an adhesive is applied to the inner surface of the socket, and then the tube is connected to the pipe. 1. A pipe connection structure characterized in that at least the inner surface side portion of the socket insertion portion up to the position is made of an elastic body having a predetermined elasticity.