JP2019086024A - Resin pipe and connection structure and connection method of resin pipe and joint - Google Patents

Abstract

To enable a lamination resin pipe having a gas barrier property to be securely connected to a metallic joint with the gas barrier property kept by easy work.SOLUTION: An inner surface of a connection port 1a of a resin pipe 1 to be connected to a joint 2 is provided so that an inner layer 14 is removed by cutting to expose a barrier layer 13 formed as an intermediate layer and the barrier layer 13 directly contacts with an outer surface of a pipe connection cylinder part 21a of the joint 2 when the resin pipe 1 is connected to the joint 2.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a laminated resin pipe including a barrier layer in an intermediate layer, and a structure for connecting the same to a joint.

Until now, metal pipes have been widely used for transporting liquids and gases, but since metal pipes are hard and hard to bend, processing and construction are difficult. Furthermore, the tube may be crushed by negative pressure or external force, or broken by a disaster such as an earthquake.
On the other hand, resin pipes are easy to process and install, and even when the pipe is temporarily crushed by negative pressure or external force, the internal pressure creeping phenomenon can cause the pipe to expand and be used, and earthquakes Even in disasters, etc., there is a use advantage that the pipe can be extended and changed its shape, so it is hard to break.

  In order to connect a resin pipe to a joint, a means for pressing the resin pipe into a ring-shaped projection provided on a nipple of the joint is generally used. Further, in order to improve the sealing performance and the removal prevention force, there are known means of interposing an adhesive or an O-ring at a connection site, or applying a restraining force from the outer peripheral side of a resin pipe with a sleeve or the like.

Among such resin pipes, for example, those used for transportation of gases such as hydrogen gas and oxygen gas are required to have excellent gas barrier properties.
As a technique for enhancing the gas barrier properties of a resin pipe, for example, in Patent Document 1 below, a laminated resin pipe in which a barrier layer formed of ethylene vinyl alcohol copolymer (EVOH) is mainly interposed between an outer layer and an inner layer. The configuration of the Further, Patent Document 2 below relates to a fastening structure of a pipe for connecting a resin pipe to a connecting pipe, in which an acute-angled portion of the connecting pipe pierces the inner layer of the resin pipe and partially cuts into the barrier layer for connection. A pipe fastening structure is disclosed.

JP 2008-55786 A JP 2005-226696 A

  At present, metal fittings without gas penetration are often used as pipe fittings used for gas transport in order to prevent gas from leaking from the joint part. When the laminated resin pipe having the barrier layer interposed therein is used for transporting the gas, when connecting the resin pipe to a metal joint, the connection portion of the joint and the inner layer of the resin pipe are in contact with each other, A gas to be transported, such as hydrogen gas or carbon dioxide, easily dissolves in the inner layer of the resin pipe, and the gas may permeate the inner layer and leak from the edge of the connection portion of the joint. It is difficult to maintain the gas barrier properties by directly connecting the gas-permeable inner layer to the joint. The same problem occurs when the joint portion of the joint and the outer layer of the resin pipe are in contact with each other.

  Further, in the pipe fastening structure in which the acute-angled portion of the connection tube partially bites into the barrier layer, it is expected that a large destructive force acts on the barrier layer and the gas barrier performance is lost. Furthermore, in this fastening structure, the joint outer shape is inevitably larger than the inner diameter of the resin pipe inner layer, so when connecting the resin pipe to the joint, a very large insertion force is required, and the connection work can be smoothly advanced Have difficulty.

  Therefore, in view of such problems in the prior art, the present invention is simple to a laminated resin pipe having gas barrier properties, a joint having good gas barrier properties while maintaining the gas barrier properties, particularly a metal joint. The task is to ensure that the connection can be made by work.

The inventors of the present invention have conducted intensive studies on improvements in resin pipes and joints to prevent gas from leaking out from the connection site when the resin pipes used for gas transport are connected to metal joints. When the inner surface of the connection port of the resin pipe is connected to the connection portion of the joint, a barrier layer is disposed on the inner surface of the connection port of the resin pipe and the outer surface of the connection portion of the joint is brought into direct contact Thus, the inventors have found that the amount of gas leaking from the connection site of both members can be suppressed to a very small amount, and the gas barrier properties can be maintained.
Further, in the case of a resin pipe formed by laminating an inner layer on the outside of the barrier layer, the inner layer of the connection port portion is made more than the other portions without completely exposing the barrier layer on the inner surface of the resin pipe connection port. It has also been found that the gas barrier properties can be maintained as described above by forming a thin film and bringing it into contact with the outer surface of the joint of the joint.

  Therefore, in the present invention, the inner surface or the outer surface of the connection port to the joint of the resin pipe including the barrier layer in the intermediate layer is formed to expose the barrier layer, or the inner layer or the outer layer of the resin pipe has a gas permeability The gas barrier property of the connection portion with the joint was maintained by forming the electrode thinner than other portions so as to be extremely small.

That is, according to the present invention, in the laminated resin pipe including the barrier layer in the intermediate layer,
Either the inner layer forming the inner surface of the connection port portion of the resin pipe connected to the joint or the outer layer forming the outer surface, the thickness of the portion on the side in contact with the pipe connection cylinder of the joint is It is characterized in that it is provided smaller than the thickness of the inner layer or the outer layer of the portion other than the connection port.
Further, the present invention provides a laminated resin pipe including a barrier layer in an intermediate layer,
The barrier layer is formed on either the inner surface or the outer surface of the connection port portion of the resin pipe connected to the joint, and the surface on the side which contacts the pipe connection cylindrical portion of the joint. I assume.
The resin pipe of the said structure can be provided so that the inner layer or outer layer of a connection port may be removed, and the inner surface or outer surface may be formed by the exposed barrier layer.

  The resin pipe of the present invention is a laminated resin pipe including a barrier layer in an intermediate layer, and is formed, for example, by laminating at least five layers of outer layer / adhesion layer / barrier layer / adhesion layer / inner layer in the order described above Can be used.

As a material of each layer, a thermoplastic resin, rubber, etc. can be used for an outer layer and an inner layer. Among them, it is preferable to use one obtained by crosslinking a thermoplastic resin.
As a thermoplastic resin, polyolefins, such as polyethylene, can be mentioned, What was manufactured by the injection molding method etc. using polyethylene as a raw material, and was bridge | crosslinked is preferable. Polyethylene polymers include low density polyethylene (LDPE), very low density polyethylene (VLDPE), linear low density polyethylene (LLDPE), medium density polyethylene (MDPE), high density polyethylene (HDPE) and mixtures thereof Be These can be arbitrarily selected according to the purpose of use, the gas to be transported, and the like.
The barrier layer is not particularly limited as long as it has gas barrier properties, and a metal thin film such as aluminum, a thermoplastic resin, a thermosetting resin, and the like can be appropriately used. Among them, it is preferable to use a thermoplastic resin from the viewpoint of coextrusion of the outer layer and the inner layer, and from the viewpoint of excellent moldability. As an example, ethylene-such as Soarnol (registered trademark: Mitsubishi Chemical Corporation) having good gas barrier properties. A vinyl alcohol copolymer resin can be used.
The adhesive layer is preferably a modified polyolefin having a polar group introduced from the viewpoint of adhesion with the barrier layer. An adhesive resin such as Modic (registered trademark: Mitsubishi Chemical Corporation) can be used as an example of the modified polyolefin.
The thickness of each layer is, for example, with a nominal diameter of 13 A, the outer layer is 0.45 mm, the outer adhesive layer is 0.05 mm, the barrier layer is 0.1 mm, the inner adhesive layer is 0.05 mm, and the inner layer is 1.5 mm It can be provided in thickness. The thickness of each layer may be varied according to the diameter of the pipe used. These numerical values can be arbitrarily selected by design depending on the purpose of use, operating temperature, operating pressure, allowable gas leakage, and the like.

In order to arrange the barrier layer on the inner surface or the outer surface of the connection port of the resin pipe, the inner layer or the outer layer of the connection port of the resin pipe laminated in multiple layers is removed to expose the barrier layer as the intermediate layer to the inner surface or the outer surface of the pipe It is possible to use means for Other means may be used to provide the barrier layer on the inner or outer surface of the connection port.
If the barrier layer is disposed on the inner surface or the outer surface of the connection port of the resin pipe, the barrier layer of the resin pipe is in direct contact with the outer surface or the inner surface of the connection portion of the joint when the connection port is connected to the joint. Since the inner layer or the outer layer which is easy to dissolve is not in contact with the joint surface of the joint, the amount of gas leakage from the connection portion of both members can be suppressed to a very small amount to prevent the occurrence of gas leakage.

In addition, as described above, even if the barrier layer is not completely exposed on the inner surface or the outer surface of the connection port of the resin pipe, the gas permeation degree is extremely reduced by forming the inner layer or the outer layer in the connection port portion thin. The gas barrier properties when connected to a joint can be maintained. Furthermore, gas barrier properties can also be adjusted by adjusting the thickness of the inner layer or the outer layer arbitrarily according to the purpose of use.
When the inner or outer layer of the resin pipe is scraped off to expose the barrier layer, it is necessary to form a thicker barrier layer in consideration of the amount of scraping off the barrier layer, but as described above, In the method of maintaining the gas barrier property by adjusting the thickness, it is not necessary to form the barrier layer to be thick beforehand, and the cost reduction of the product can be directly reflected.
In this case, if the thickness of the inner layer or outer layer of the connection port portion is set to 70% or less, preferably 50% or less, more preferably 30% or less of the inner layer of the other portion, the gas permeability is small. It is possible to effectively prevent the occurrence of gas leakage when connecting a resin pipe to a joint. Since the amount of allowable gas leakage also varies depending on the purpose of use and the gas to be transported, the thickness of the inner layer or the outer layer in the connection port portion can be arbitrarily adjusted.
For example, when used for transportation of a gas having a very small molecular size such as hydrogen, the thickness of the inner layer or outer layer in the connection port portion is 10% or less of the thickness of the inner layer or outer layer in the other portion in order to maintain gas barrier properties. It is more preferable to set it to 7% or less, preferably 5% or less.
In the case where another layer such as an adhesive layer is formed between the barrier layer and the inner layer or the outer layer, the inner layer or the outer layer may be completely scraped off to leave the adhesive layer.

  In order to remove the inner layer or the outer layer of the connection port of the resin pipe or to form the inner layer or the outer layer thin, for example, using a cutting tool such as a drill or scraper, cut the outer layer of the inner layer or the outer surface of the end inner surface A means for forming the connection port with the joint can be used.

  The connection structure of the resin pipe and the joint thus formed uses, for example, a joint having a joint body having a pipe connection cylindrical portion to which the end of the resin pipe is connected as a joint and a fixing member fitted on the outer periphery of the joint body The pipe connection cylinder of the joint body is inserted into the connection port of the resin pipe of the above configuration, and either the outer surface or the inner surface of the pipe connection cylinder is brought into contact with the inner surface or the outer surface of the connection port of the resin pipe to join the resin pipe Can be configured by connecting to

Further, in the method of connecting a resin pipe and a joint according to the present invention, a barrier layer is provided in the middle layer of a joint having a joint body having a pipe connection cylindrical portion to which the end of the resin pipe is connected and a fixing member fitted around the joint body. A method of connecting laminated resin pipes including
Cutting either the inner layer or the outer layer of the connection port of the resin pipe connected to the joint thinly, or removing any one of the inner layer and the outer layer to expose the barrier layer;
Inserting the pipe connection tube portion of the joint body into the connection port of the resin pipe, and bringing the inner surface or outer surface of the connection port of the resin pipe into contact with either the inner surface or the outer surface of the tube connection tube;
Fixing the fixing member on the outer periphery of the joint body and fixing the resin pipe inserted in the pipe connection cylinder to the joint body;
It is characterized by having.

The joint to which the resin pipe is connected is preferably a metal joint from the viewpoint of maintaining gas barrier properties, but is not limited thereto. For example, a joint made of a material having gas barrier properties can also be used.
Further, the joint may be configured as a fixing member having a cap nut or slide ring fitted to the outside of the joint main body, or a band provided around the outer periphery of the joint main body for fastening.

According to the resin pipe of the present invention, the inner layer or the outer layer of the connection port connected to the joint is thinly formed so that the gas does not easily dissolve in the inner surface or the outer surface, or a barrier layer is formed on the inner surface or the outer surface of the connection port. Since it is formed to be exposed, the gas barrier property can be maintained by directly contacting the surface of the pipe connection tube portion of the joint and connecting the resin pipe, and gas leakage from the connection portion with the joint can be maintained. Can be effectively prevented.
In addition, by forming or removing the inner layer or outer layer of the connection port in a thin wall or cutting the inner surface or outer surface of the resin pipe, connection with the joint can be smoothly performed without requiring a large insertion force. As a result, the connecting operation of the resin pipe and the joint can be performed simply and in a short time and reliably.

It is an end sectional view of a resin pipe of one embodiment of the present invention. (A) is a block diagram of the coupling which expanded the resin pipe and member of FIG. 1, (B) is a block diagram of the process in which a resin pipe is connected to a coupling. It is principal part sectional drawing of the state which connected the resin pipe to the coupling | joint of FIG. It is the connection end view of the resin pipe and coupling of FIG. 3, and is the figure which expanded and showed the contact state of the connection port of a pipe, and the pipe | tube connection cylinder part of a coupling. It is the figure which expanded and showed the contact state of the connection port of a pipe, and the pipe connection cylinder part of a coupling when connecting the resin pipe of other embodiment of this invention to a coupling.

  Hereinafter, although the resin pipe of this invention and one embodiment of the connection structure of this and a coupling are described, this invention is not limited to this embodiment.

  FIG. 1 shows a resin pipe according to an embodiment of the present invention, and this resin pipe 1 is a laminated resin pipe including a barrier layer 13 in an intermediate layer, and the outer layer 11 / adhesive layer 12 / barrier layer 13 / adhesive layer 12 / the inner layer 14 is integrally formed by laminating and integrally formed into a tubular shape by extrusion molding, and the inner surface of the connection port 1a with the joint 2 described later provided at the one end is formed by the barrier layer 13 It is a thing.

Specifically, the inner surface of the connection port 1a of the resin pipe 1 is removed by an amount such that the inner layer 14 is in contact with the outer surface of the pipe connection cylindrical portion 21a of the joint 2 described later from the end of the pipe A certain barrier layer 13 is provided in an exposed shape, and the connection port 1a is formed so as to be thinner and thinner than the other portions of the pipe by the thickness of the removed inner layer 14 is there.
The processing for exposing the barrier layer 13 on the inner surface of the connection port 1a can be performed, for example, by inserting a cutting tool such as a scraper that scrapes the inner layer 14 at the end of the resin pipe 1.

  The joint 2 to which the resin pipe 1 is connected is, for example, a metal joint shown in FIG. 2A, and is provided with a pipe connection cylindrical portion 21a at the center of the open end on one side and an outer cylindrical portion 21b around it. Using the joint body 21, the split ring 22 mounted on the pipe connection cylindrical portion 21a together with the resin pipe 1, and the cap nut 23 as a fixing member externally fitted to the outer periphery of the joint body 2; it can.

  The connection in this case is, first, as shown in FIG. 2 (B), a joint in a state where the cap nut 23 and the split ring 22 pass through the resin pipe 1 with the barrier layer 13 exposed on the inner surface of the connection port 1a. Insert the connection port 1a of the resin pipe 1 into the pipe connection cylinder 21a of the main body 21, then press the split ring 22 into the inner surface of the outer cylinder 21b of the joint body 21 and the outer surface of the connection port 1a of the resin pipe 1 As shown in FIG. 3, the cap nut 23 is put on the outer surfaces of the split ring 22 and the outer cylindrical portion 21b and externally fitted to the outer peripheral surface of the joint main body 21, and the connection port 1a of the resin pipe 1 is made of the pipe connecting cylindrical portion 21a. It can carry out by pressure-contacting and fixing to an outer peripheral surface.

In a state where the resin pipe 1 is connected to the joint 2, as shown in FIG. 4, the barrier layer 13 exposed on the inner surface of the connection port 1a of the resin pipe 1 is directly on the outer peripheral surface of the pipe connection cylindrical portion 21a of the joint 2. Since the inner layer 14 in which the gas easily dissolves is not in contact with the outer surface of the pipe connection cylinder 21a, the gas flowing in the resin pipe 1 does not leak from the connection portion with the joint 2 and high gas barrier It is possible to hold.
Moreover, since the connection port 1a of the resin pipe 1 is provided in a thin wall which is cut by the thickness of the inner layer 14, it is possible to smoothly perform the connection operation to the joint 2.

  FIG. 5 shows a resin pipe 1 according to another embodiment of the present invention, in which the end of the resin pipe 1 is inserted into the pipe connection cylinder 21a of the joint 2 and the inner surface of the pipe connection cylinder 21a is inserted. It is an aspect which the outer surface of the connection port 1a of the resin pipe 1 contacts, and connects.

  Specifically, the resin pipe 1 is a laminated resin pipe including a barrier layer 13 in an intermediate layer in which five layers of outer layer 11 / adhesion layer 12 / barrier layer 13 / adhesion layer 12 / inner layer 14 are integrally laminated in the same manner as the above embodiment. The outer layer 11 is cut with a scraper over the length of the outer surface of the end of one side from the edge and the inner surface of the pipe connection cylindrical portion 21a of the joint 2 coming into contact with the outer edge 11 The connection port 1a with the joint 2 is formed thinly so as to have a thickness that allows the adhesive layer 11 to be exposed.

  Also in the resin pipe 1 of the present embodiment, as shown in FIG. 5, the connection port 1a of the resin pipe 1 contacts the outer surface of the pipe connection cylindrical portion 21a of the joint 2 in the state of being connected to the joint 2 Since the outer layer 11 is thinly formed so that the gas hardly dissolves, the gas barrier property can be maintained, and the occurrence of the gas leakage from the connection portion with the joint 2 can be effectively prevented. is there.

The following evaluation was performed about the connection structure of the resin pipe of this invention, and a coupling.
<Example>
A test pipe of resin pipe was manufactured using an oxygen permeation prevention crosslinked polyethylene pipe with a nominal diameter of 16A (trade name "Excel pipe O2 stop" (Excel pipe is a registered trademark) manufactured by Mitsubishi Chemical Infratec Co., Ltd.).
This resin pipe is a laminated resin pipe in which five layers of outer layer / adhesion layer / barrier layer / adhesion layer / inner layer are integrally laminated including the gas barrier layer in the middle layer to form a laminated resin pipe. The adhesive layer is provided with a thickness of 0.05 mm, the barrier layer is provided with a thickness of 0.1 mm, the inner adhesive layer is provided with a thickness of 0.05 mm, and the inner layer is provided with a thickness of 1.55 mm.
The resin pipe is cut into a length of about 10 cm, and the inner surface of the pipe is cut at a width of 13 mm from the end to the other end using a scraper at one end of the resin pipe. A connection port with the joint was formed.
The thickness of the inner layer of the connection port part was about 3% of the inner layer of the other part (the part not cut) although the inner layer was partially completely removed and the adhesive layer or barrier layer was exposed. It was below.
Then, using a company-made metal joint having the same configuration as that shown in FIG. 2, this was connected to the connection port of the resin pipe to produce a test body of the example. That is, as described above, with the cap nut and split ring in the resin pipe, insert the connection port of the resin pipe into the pipe connection cylindrical portion of the joint body, and then, the split ring Press-fit onto the outer surface of the connection port of the pipe, and then insert a cap nut on the outer surface of the split ring and outer cylinder part to strongly bond to the fitting body, and press the connection port of the resin pipe to the outer peripheral surface of the pipe connection cylinder part Fixed. In addition, the metal joint used that by which the outer diameter of the pipe | tube connection cylinder part was set to 20.2 mm.

Comparative Example
As a comparative example, the same resin pipe as that of the previous embodiment is used and cut into a length of 10 cm, and the same metal joint as that of the previous embodiment is connected to the one end thereof in the same manner as above. The test body of the comparative example of was produced.
In addition, using a cross-linked polyethylene tube with a nominal diameter of 16A (trade name "Excel Pipe" (registered trademark), manufactured by Mitsubishi Chemical Infratec Co., Ltd.), this is cut into a length of 10 cm, and the above-described embodiment is performed at one end thereof. The same metal joints as in the example were connected in the same manner as described above to prepare a test body of the second comparative example. In addition, the metal coupling of the comparative example used the thing of the standard dimension which the resin pipe of nominal diameter 16A connects.

Using a helium leak tester (console type fully automatic helium leak detector MS-50HS) manufactured by VIC, the presence or absence of leak from the joint of the test body of the example and the comparative example is detected by the helium leak test (pressurization method) Then, the test body was evaluated.
As a result, while the leak rate of the test body of the example is 8.20 × 10 ⁻⁹ Pa · m ³ / sec, the leak rate of the test body of the first comparative example is 1.50 × 10 ^−3. The leak amount of the test object of Pa · m ³ / sec and the second comparative example is 1.00 × 10 ⁻² Pa · m ³ / sec, and the gas barrier property in which the connection structure of the resin pipe and the joint according to the embodiment is sufficient It could be confirmed that the
It is considered that this is because the inner layer of the connection port portion of the resin pipe is extremely thin, and therefore, when the joint is connected to the connection port, the permeability of the gas permeating through the thin inner layer becomes extremely small. Therefore, the inner layer of the connection port of the resin pipe is completely removed, and the inner surface of the connection port is formed by the exposed adhesive layer, or the inner layer of the connection port and the adhesive layer are completely removed to expose the inner surface of the connection port. In the case of forming a barrier layer, when the joint is connected to the connection port, the gas barrier property is considered to be further improved because there is no inner layer which is a portion through which gas passes.

  In addition, the resin pipe 1 shown in figure shows the form of an example of this invention, and the coupling 2 which the resin pipe 1 connects also shows the form of an example. The present invention is not limited to these exemplary forms, and can be configured in other appropriate forms.

Reference Signs List 1 resin pipe, 11 outer layer, 12 adhesive layer, 13 barrier layer, 14 inner layer, 2 joint, 21 joint main body, 21a pipe connection cylindrical portion, 21b outer cylindrical portion, 22 split ring, 23 cap nut

Claims (7)

In a laminated resin pipe including a barrier layer in an intermediate layer,
Either the inner layer forming the inner surface of the connection port portion of the resin pipe connected to the joint or the outer layer forming the outer surface, the thickness of the portion on the side in contact with the pipe connection cylinder of the joint is A resin pipe characterized by being smaller than the thickness of the inner layer or the outer layer of a portion other than the connection port. In a laminated resin pipe including a barrier layer in an intermediate layer,
The barrier layer is formed on either the inner surface or the outer surface of the connection port portion of the resin pipe connected to the joint, and the surface on the side which contacts the pipe connection cylindrical portion of the joint. Resin pipe to be.   The resin pipe according to claim 2, wherein the inner layer or the outer layer of the connection port is removed, and the inner surface or the outer surface is formed by the exposed barrier layer.   The resin pipe according to any one of claims 1 to 3, wherein at least five layers of outer layer / adhesion layer / barrier layer / adhesion layer / inner layer are laminated. The resin pipe is connected to a joint having a joint body having a pipe connection cylindrical portion to which the end of the resin pipe is connected and a joint having a fixing member fitted on the outer periphery of the joint main body,
The pipe connection cylinder part of the joint main body is inserted into the connection port of the resin pipe according to any one of claims 1 to 4, and either the inner surface or the outer surface of the pipe connection cylinder section is the inner surface or the outer surface of the connection port of the resin pipe. Connection structure of resin pipe and joint which connects resin pipe to joint by making contact. In a method of connecting a laminated resin pipe including a barrier layer to an intermediate layer, to a joint having a joint body having a pipe connection cylindrical portion to which an end of a resin pipe is connected and a fixing member fitted on the outer periphery of the joint body
Cutting either the inner layer or the outer layer of the connection port of the resin pipe connected to the joint thinly, or removing any one of the inner layer and the outer layer to expose the barrier layer;
Inserting the pipe connection tube portion of the joint body into the connection port of the resin pipe, and bringing the inner surface or outer surface of the connection port of the resin pipe into contact with either the inner surface or the outer surface of the tube connection tube;
Fixing the fixing member on the outer periphery of the joint body and fixing the resin pipe inserted in the pipe connection cylinder to the joint body;
And a method of connecting the resin pipe and the joint.   The method for connecting a resin pipe and a joint according to claim 6, wherein the inner layer or the outer layer of the connection port of the resin pipe is cut or removed using a cutting tool such as a scraper.

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