JP2002181275A - Plastic tube connection structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable easy and reliable connection between plastic tubes or compression joints without using an adhesive or means by a heat fusion method. SOLUTION: A connecting end portion 1 'of a plastic tube 1 to be connected is coated with a plastic connecting short tube 2 having heat shrinkability, and the connecting short tube is thermally contracted to connect the tube. It is made to adhere tightly to the part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to various kinds of physicochemical / analytical instruments including liquid chromatographs, various production processes for pharmaceuticals, semiconductors, liquid crystals, etc., and to remove dissolved gases in liquids in these instruments and production processes. Deaerator,
The present invention relates to a connection structure of a plastic tube used for the like. More specifically, the present invention relates to a connection structure for connecting plastic tubes in communication with each other in the above-described device and production process, and a connection structure for connecting a plastic tube to a device side using a compression fitting. Things.

[0002]

2. Description of the Related Art When plastic tubes are connected to each other in a communicating manner, especially when tubes made of a fluororesin are connected to each other in a communicating manner, connection by an adhesive is impossible due to the characteristic property of the fluororesin. Therefore, the connection by heat fusion is performed, but the work is not only very skillful, but when the thickness of the tubes connected to each other is thin or the outer diameter is small, it becomes extremely difficult or impossible to connect. .

[0003] For example, a plastic tube having a property of allowing only gas to pass therethrough and preventing liquid permeation is installed in a decompression container, and the degassed liquid is introduced into the tube while depressurizing the inside of the decompression container. In a deaerator having a mechanism for degassing dissolved gas through the tube membrane by flowing the gas, the thickness of the degassing tube for flowing the liquid to be degassed is made as thin and thin as possible in order to improve degassing efficiency. It is effective to do. However, when connecting a plastic tube to a device side (for example, a connection port provided in a decompression container) using a compression fitting, not only the degassing tube but also the plastic tube is made thinner. When formed, the connection end portion of the tube is crushed by the compression fitting, so that it cannot be tightened with a high torque, and as a result, a problem such as leakage of liquid from the connection portion by the compression fitting occurs. This is an issue that needs to be resolved early. In addition, when the outer diameter of the tube is reduced, only the compression fittings are generally available on the market of 1/16 inch or more, so that it is necessary to use custom-made products which are very expensive in terms of cost. In addition, there arises a problem that it may be impossible to manufacture the compression pipe joint itself, and this has also been a problem to be solved at an early stage.

On the other hand, a plurality of (a few to several tens, several hundred,
When there are several thousands of plastic tubes, the ends of which are integrally bound together and used as a tube element, for example, when a pinhole is found in one of them, or If one or more of the tubes are missing or cut, especially if the plastic tube is made of fluororesin, the above pinhole can be closed or the missing or cut tubes can be connected and repaired. As a result, the entire tube element had to be discarded.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of such a conventional problem. Even if the plastic tubes are made of a fluororesin, the plastic tubes can be bonded to each other using an adhesive. And can be easily and reliably connected in a continuous manner without using a means by a heat fusion method, and when connecting a plastic tube to a device side using a compression fitting, the plastic tube is made thicker. Even if it is formed thin and thin, it can be connected simply and securely using a commercially available ordinary compression fitting without causing liquid leakage, and the plastic tube has defects including pinholes and cuts. An object of the present invention is to provide a connection structure for a plastic tube that can be easily and reliably repaired when it occurs.

[0006]

The plastic tube connecting structure of the present invention for achieving the above object is a connecting structure for connecting the plastic tubes in a communicating manner. A plastic connecting short tube having heat shrinkability is coated over the outer periphery of the connection terminal portion, and the short tube for connection is thermally contracted so as to be tightly integrated with the outer periphery of the connection terminal portion of the two tubes. (Claim 1).
In this case, the connection short pipes are overlapped over two or more outer peripheral portions of the connection terminals of the two tubes to be connected to each other so as to be coaxially coated, and the plurality of connection short pipes are thermally contracted, respectively. It is also conceivable that the two tubes are tightly integrated with the outer periphery of the connection terminal portion or the other short tube for connection which is superimposed (claim 2). Further, the connection structure of another plastic tube according to the present invention,
A connection structure for connecting a plastic tube to a device side by using a compression fitting, wherein the outer periphery of a connection end portion of the tube is covered with a heat-shrinkable plastic connection short tube, and the connection short tube is connected. It is characterized in that the tube is tightly integrated with the outer periphery of the connection terminal portion of the tube by heat shrinking (claim 3). Also in this case, two or more of the connecting short tubes are coaxially superimposed and coated on the outer periphery of the connecting terminal portion of the tube, and the plurality of connecting short tubes are thermally contracted, thereby connecting the connecting terminals of the tube. It is conceivable that the outer circumference of the part or the other connecting short pipe which is superimposed is tightly integrated (claim 4). In the present invention, a compression pipe joint (compressi
On fitting) is a type of pipe fitting in which a (plastic) tube is tightened inward from the outside without receiving a rotational torque in the circumferential direction, and is simply called fitting, or a ferrule or ferrule ( fe
Refers to fittings that are sometimes referred to as rrules. Further, the present invention covers not only a normal pipe connection but also a plastic connection short pipe having heat shrinkability over a defective portion including a pinhole or a cut in a part of a plastic tube, and the connection short pipe. The present invention proposes a plastic tube repair structure characterized in that the tube is heat-shrinked to be tightly integrated with the outer periphery of the defective portion (claim 5). In a preferred embodiment to which the present invention is applied, the plastic tube is made of a fluorine-based resin or a silicon resin, and the connecting short tube is formed of the same material as the plastic tube. Is preferred.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to the illustrated embodiment, and various variations are considered. Therefore, the same components are denoted by the same reference numerals, and the description thereof will not be repeated. In the figure, reference numeral 1 denotes a plastic tube, and reference numeral 2 denotes a plastic connecting short tube.

The plastic tube 1 to which the connection structure according to the present invention is applied is made of a generally known plastic material regardless of whether it is thermoplastic, thermosetting, or flexible. Although it can be applied to a tube, it is preferable to apply to a fluorine-based resin or a silicone resin, which is difficult or impossible to connect with an adhesive or the like. Further, the thickness and outer diameter of the tube 1 used can be applied to a tube having a normally used specification. However, since the wall is too thin, not only the connection between the tubes but also the connection by a compression pipe joint can be performed. It is preferable to apply the present invention to a plastic tube having a small thickness or a small thickness, which makes it difficult.

As the fluorine resin material for forming the tube 1, polytetrafluoroethylene resin (PTFE) is used.
Alternatively, a fluorinated ethylene propylene resin (FEP), an ethylene tetrafluoroethylene resin (ETFE), a perfluoroalkoxy resin (PFA), or the like may be used. As the silicon resin material, a methyl silicone rubber may be used.

When the plastic tubes 1 and 1 are connected to each other in a communicating manner, as shown in FIGS. 1 (a) and 1 (b), the heat shrinkage formed to an appropriate length is required. Connecting ends 1 ′ of tubes 1, 1 to be connected to each other at both ends of a connecting short tube 2 made of plastic having
1 'is inserted, and connection end portions 1' of tubes 1 and 1 are inserted.
The connection short pipe 2 is covered with the connection short pipe 2 coaxially over the outer periphery of 1 ′, and in this state, the connection short pipe 2 is brought into contact with, for example, hot air or a high-temperature liquid from the outside to thermally shrink the connection short pipe 2. Let it. Then, the connection short pipe 2 is tightly integrated with the outer periphery of the connection end portions 1 ′, 1 ′ of the two tubes 1, 1 connected to each other, and the two tubes 1, 1 communicate with each other via the connection short pipe 2. It will be connected in a shape. In this case, the end faces of the connection end portions 1 ', 1' of the tubes 1, 1 to be connected to each other may be abutted inside the connection short tube 2, or they are appropriately separated as shown in the illustrated embodiment. You may.

The connecting short pipe 2 is formed to have an inner diameter slightly larger than the outer diameter of the tubes 1 and 1 connected to each other, and to have a necessary length according to a situation used for connection. And
The connecting short tube 2 is not particularly limited as long as it is a plastic material having heat shrinkability. However, the characteristics of the tube 1 used in an apparatus in which the tube 1 is used or in a production process are strong. If affected, it is preferable to use tubes made of the same material as the tubes 1 and 1 connected to each other. That is, tube 1,
When 1 is formed of, for example, a fluorine-based resin material, it is preferable that the connecting short tube 2 is also formed of a fluorine-based resin material.

When the plastic tubes 1 and 1 are connected to each other in a communicating manner, a plurality of connecting short tubes 2 may be used instead of one. That is, FIG.
In the embodiment shown in (c), the two tubes 1 and 1 are connected in a communicating manner by one connecting short tube 2, and at the same time or after this, both end portions of the connecting short tube 2 are connected. And a separate connecting short pipe 2 ′,
2 'is overlapped in a coaxial manner to be covered, and these connecting short tubes 2', 2 'are thermally shrunk, respectively, so as to be tightly integrated with both tubes 1, 1 or the other connecting short tube 2 which is superimposed. It is to make it. With this configuration, it is possible to reinforce both end portions of the connecting short pipe 2 and improve the strength and airtightness of the connecting end portions 1 ′, 1 ′ of the tubes 1, 1.

Next, the plastic tube 1 is connected to the device 3.
A connection structure to be connected using the compression pipe joint 4 on the side will be described. When the plastic tube 1 is connected to the device 3 using the compression fitting 4, particularly when the tube 1 to be connected is formed to be thin and thin, as shown in FIG. Connection terminal part outer circumference 1 '
Is coated with a short tube 2 made of plastic having heat shrinkability, and the short tube 2 for connection is thermally shrunk so as to be tightly integrated with the outer periphery 1 'of the connection terminal portion of the tube 1. Also in this case, two or more connecting short pipes 2 are coaxially superimposed and coated on the outer periphery 1 'of the connecting terminal portion of the tube 1, and the plurality of connecting short pipes 2 and 2' are coated.
Can be considered to be tightly integrated with the tube 1 or another connected short tube 2 ′ by heat contraction.

FIG. 3 shows an example of a deaerator as an example of a specific device 3 for connecting the tube 1. In this deaeration apparatus, one or more plastic deaeration tubes 1 having a property of passing only gas and preventing liquid permeation are installed in a decompression container 6 installed in a housing 5. The openings 1a and 1b at both ends of the deaeration tube 1 are connected to the compression pipe joints 4 and 4 attached to the decompression vessel 6 in a communicating manner, respectively.
The degassed liquid is passed through one compression pipe joint (liquid inlet) 4 of the decompression vessel 6 from the liquid inlet 1a of the degassing tube 1 into the degassing tube 1 while controlling the pressure in the depressurization. The dissolved gas is deaerated into the decompression container through the deaeration tube 1 while the gas-liquid flows out of the liquid outlet 1b of the deaeration tube 1. And, in the compression pipe joints 4 and 4 provided in the decompression container 6,
Another plastic tube 1 for supplying the liquid to be degassed to the above-mentioned degassing tube 1 is connected so as to be separable from the outside of the housing 5.

Here, a connection structure by the compression pipe joint 4 will be described. As shown in FIG. 3, the compression fitting 4 basically includes an interference fit sleeve 4a and the interference fit sleeve 4a.
And a connecting member 4b that screw-connects them. The interference fit sleeve 4a has a knob 41a for tightening operation formed at one end thereof, and a male screw 42a on the outer periphery at the other end.
Is formed, and an insertion hole 43a for penetrating the plastic tube 1 connected to the connection member 4b is formed in the axial center so as to penetrate along the longitudinal direction, and is opposite to the operation knob 41a. The other end side of the
A tightening portion 44a for tightening the tube 1 inserted through the tube 1a inward from the outside is formed. on the other hand,
On the inner peripheral surface of the connection member 4b, a female screw 41b to be screwed with the male screw 42a of the interference fit sleeve 4a and a tapered hole 4 for tightening the tightening portion 44a of the interference fit sleeve 4a.
2b is formed.

When connecting the tube 1 to the device 3, the connecting member 4 b of the compression fitting 4 must be connected to the device 3 in advance.
Then, the plastic tube 1 to be connected is inserted through the insertion hole 43a of the interference fit sleeve 4a, and the interference fit sleeve 4a is screwed to the connection member 4b. Then, with the screwing advance of the interference fit sleeve 4a, the tightened portion 44a of the interference fit sleeve 4a enters the depth of the tapered hole 42b of the connection member 4b, and the outer peripheral surface of the tightened portion 44a of the interference fit sleeve 4a. And the inner peripheral surface of the tapered hole 42b of the connecting member 4b is airtightly sealed, and at the same time, the tube 1 inserted through the insertion hole 43a of the interference fitting sleeve 4a is tightened by the fastening portion 44 of the interference fitting sleeve 4a.
a, the screw is tightened inward from the outside without receiving a rotational torque. As a result, the inner peripheral surface of the tightened portion 44a of the interference fit sleeve 4a and the outer peripheral surface of the tube 1 are tightly adhered to each other, so that the tube 1 is connected to the connecting member 4b in a communicating manner without causing liquid leakage. You.

Next, a repair structure in the case where there is a defective portion including a pinhole or a cut in a part of the plastic tube 1 will be described. In this case, a plastic connecting short tube (not shown) having heat shrinkability is coated over a defective portion including a pinhole and a cut in the plastic tube (not shown), and the connecting short tube is heated. By contracting, the outer periphery of the defective portion is tightly integrated. That is, when there is a pinhole, the connecting short pipe is covered coaxially so as to cover the pinhole, and the connecting short pipe is thermally shrunk to be tightly integrated with the pinhole portion. The pinhole is closed and repaired, and when a plastic tube is cut, a plastic connecting short tube having heat shrinkability is coated over the cut end portion outer periphery, and the connecting short tube is used. The cut end portions are tightly integrated with the outer periphery of the cut end portion of the cut tube by heat shrinkage, and the cut end portions are connected in a communicating manner.

[0018]

According to the connecting structure for plastic tubes according to the first aspect of the present invention, when the plastic tubes are connected to each other in a communicating manner, the plastic tubes are connected to each other over the outer periphery of the connecting terminal portion of the plastic tubes. Since the plastic short connection tube having heat shrinkage is covered, and the connection short tube is thermally contracted, the two connection tubes are tightly integrated with the outer periphery of the connection terminal portion.
The plastic tubes can be simply and reliably connected to each other without using an adhesive or a means such as heat fusion.

According to the connecting structure for a plastic tube according to the second aspect of the present invention, the connecting short tube is
Two or more of the connecting ends of the two tubes connected to each other are overlaid and covered, and the plurality of connecting short tubes are heat-shrinked, respectively, so that the two tubes or the other connected short tubes overlap with each other. Since they are integrated, the connection between the two tubes can be easily and inexpensively reinforced, and there is no fear of liquid leakage or the like.

According to a third aspect of the present invention, there is provided a connecting structure for connecting a plastic tube to a device by using a compression fitting. The outer periphery of the terminal is covered with a short pipe for connection made of heat-shrinkable plastic,
Since the connecting short tube is heat-shrinked so as to be tightly integrated with the outer periphery of the connecting terminal portion of the tube, even if the thickness of the plastic tube to be connected is thin and thin, the tube is Since the outer diameter of the connection terminal portion is thick and thick and reinforced, it is possible to use a commercially available ordinary compression fitting when connecting a plastic tube to the device side using a compression fitting. At the same time, it is possible to tighten with a high torque, and the connection can be made without causing liquid leakage at the connection portion.

Further, according to the connecting structure for a plastic tube according to the fourth aspect of the present invention, two or more of the connecting short pipes are overlapped and covered on the outer periphery of the connecting end of the tube. Each of the connecting short pipes is heat-shrinked so as to be tightly integrated with the tube or another stacked connecting short pipe, so that only a small number of connecting short pipes need to be prepared for compression of various sizes. It is possible to easily cope with the pipe joint, and it is easy to finely adjust the outer diameter of the connection end portion of the tube to the one most suitable for the compression pipe joint.

According to the repair structure for a plastic tube according to the fifth aspect of the present invention, a plastic connection having heat shrinkability over a defective portion including a pinhole and a cut in a part of the plastic tube. The short tube for connection is covered, and the short tube for connection is heat-shrinked so as to be tightly integrated with the outer periphery of the defective portion, so that both ends of a plurality of plastic tubes are united together to form a tube element. For example, when a pinhole is found in one of them or when one or more of them is missing or cut for some reason, a short pipe for connecting to the pinhole part is used. And cover it with heat by shrinking it together to cover it, or cover the connecting short tube over the missing or cut portion of the tube. It is possible to repair the defective or disconnected by Umate thermal shrinkage. Therefore, even if a defect including pinholes or cuts occurs in the plastic tube, the tube can be easily and reliably repaired, and it is not necessary to dispose of the entire tube element as in the conventional case, and the cost can be reduced. It becomes possible.

According to a sixth aspect of the present invention, the plastic tube is made of a fluororesin or a silicone resin, and the connecting short tube is connected to the plastic tube. Since it is made of the same kind of material, it is possible to easily connect tubes made of fluorine resin or silicon resin, which cannot be connected with an adhesive, etc. The use of the connecting short pipe with respect to the substance that comes into contact with the inside or outside of the tubing does not cause any adverse effects.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an embodiment of the present invention.

FIG. 2 is a perspective view showing another embodiment of the present invention.

FIG. 3 is a schematic sectional view showing still another embodiment of the present invention.

[Explanation of symbols]

 1: tube made of plastic 1 ': connection end portion 2, 2' ,: short tube for connection 3: equipment 4: compression joint

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Nami Ueda, Inventor 5-8-6 Nishi-Aoki, Kawaguchi-shi, Saitama FRC Term Co., Ltd. (Reference) 3H019 HA06 JA02 4F211 AA16 AA33 AD05 AD12 AG08 AH11 TA10 TC11 TD07 TH06 TN24

Claims (6)

[Claims] 1. A connecting structure for connecting plastic tubes in a communicating manner, wherein the connecting tubes are covered with a heat-shrinkable plastic connecting short tube over the outer periphery of a connecting terminal portion of the plastic tubes connected to each other. A connecting structure for a plastic tube, wherein the connecting short tube is heat-shrinked so as to be tightly integrated with the outer periphery of the connecting terminal portion of the two tubes. 2. The two short pipes for connection are overlapped and covered around the outer periphery of the connection end portion of the two tubes connected to each other, and the plurality of short pipes for connection are thermally shrunk respectively. 2. The plastic tube connecting structure according to claim 1, wherein said plastic tube connecting structure is tightly integrated with a tube or another connected short tube. 3. A connection structure for connecting a plastic tube to a device side using a compression fitting, wherein a short connection tube made of heat-shrinkable plastic is coated on an outer periphery of a connection end portion of the tube. A connection structure for a plastic tube, characterized in that the connection short tube is heat-shrinked so as to be tightly integrated with the outer periphery of a connection terminal portion of the tube. 4. The connection terminal portion of the tube is covered with two or more of the connecting short tubes by overlapping and covering each of the plurality of connecting short tubes by heat shrinking each of the plurality of connecting short tubes. 4. The plastic tube connecting structure according to claim 3, wherein said plastic tube connecting structure is tightly integrated with said connecting short pipe. 5. A plastic connecting short tube having heat shrinkability is covered over a defective portion including a pinhole or a cut in a part of the plastic tube, and the connecting short tube is thermally shrunk. A plastic tube repair structure characterized by being tightly integrated with the outer periphery of the defective part. 6. The plastic tube according to claim 1, wherein the plastic tube is made of a fluorine-based resin or a silicone resin, and the connecting short tube is made of the same material as the plastic tube. Connection structure.