JPH02150592A - Tube joint - Google Patents

Abstract

PURPOSE:To reduce a pressure loss as well as to economize a setup space by installing a metallic socket formed with a nut part which diametrally contracts a tube insert port of a plastic joint body, and making an outer cylinder part of its tubular groove into a retightnenable structure. CONSTITUTION:After a tube body 2 is passed through a hollow part 8a of a socket 8, a protective tube 2c at a tip of the tube body 2 and a pressure-proof reinforced layer 2b are peeled off, and only an inner layer tube 2a is projected out, inserting it into a joint body 6 from a tube body insert port 6e, and a tip of the tube 2a is made contact with a step difference 6f. Next, the socket 8 is screwed in the joint body 6, and an insert port 6b is diametrally contracted by a taper part, making a seal member 6g contact with an outer circumferential surface of the inner layer tube 2a under pressure, thus a seal effect is secured. Then, a diametrally expanded part at each tip of the protective tube 2c and the pressure-proof reinforced layer 2b inserted in a tubular groove 8d of the socket 8, and an outer cylindrical part 8f is retightened inward, then it is held between both outer and inner cylindrical parts 8f and 8e.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a pipe joint that can be easily connected to a pipe body for transferring fluids such as ultrapure water and chemicals.

[Conventional technology]

Conventionally, there are various types of pipe joints, but among them, one with a relatively simple structure is, for example,
0-149590 is known.

The pipe joint described in this publication has an inner cylindrical part (insert part) that protrudes in the axial direction from the joint body, and is tightened by fitting the pipe body onto the outer peripheral surface of the inner cylindrical part. By screwing into the outer periphery of one end of the joint body, the tube can be pressed in the thickness direction of the tube through the sleeve, and the connection can be established with a predetermined pull-out strength.

[Problem to be solved by the invention]

However, in the above-mentioned conventional pipe joint, the tip of the inner cylinder part is stepped at the connection part between the flow path in the inner cylinder part and the flow path in the pipe body, so liquid pools occur and the flow path There was an unresolved problem that resistance was generated and pressure loss increased.

On the other hand, in order to avoid this problem, for example,
-42287 and Utility Model Application Publication No. 60-81378, there are some ideas such as rounding or tapering the tip of the inner cylinder (insert part), but it is impossible to completely eliminate liquid accumulation and pressure loss. I can't. Furthermore, in order to solve this problem, the inner cylinder part was eliminated and the pipe was inserted directly into the tube insertion port.
There is a structure in which the outer peripheral surface of the tube is sealed and gripped after the tube is inserted (for example, Japanese Utility Model Publication No. 59-3089)
(Refer to No.), such a structure has problems such as insufficient gripping function, although the joint is bulky in the radial direction.

Therefore, this invention was made by focusing on the various problems of the prior art, and it is possible to eliminate liquid accumulation,
The problem to be solved is to reduce flow path resistance, reduce pressure loss, and suppress radial bulk to save installation space.

[Means to solve the problem]

In order to solve the above problems, the present invention uses a tube body having an inner layer tube and an outer layer tube covering the outside of the inner layer tube. The pipe joint has a tube insertion port into which the inner tube can be inserted at the axial end thereof, a tapered threaded portion on the outer peripheral surface of the insertion port, and a tapered threaded portion on the outer peripheral surface of the inner tube. A joint body made of synthetic resin is provided with an abuttable sealing member on the inner peripheral surface of the tube insertion port, and a nut portion that is screwed into the threaded portion of the joint body to reduce the diameter of the tube insertion port is attached in the axial direction. - a metal socket formed at one end and having a cylindrical groove drilled at the other axial end into which the end of the outer tube can be inserted; the cylindrical groove of the socket is connected to the inner cylindrical part; The outer cylindrical part formed by the cylindrical part has a structure that can be crimped.

[Effect]

In this invention, when the inner layer tube of the tubular body is inserted into the tube insertion port of the joint body and the socket is screwed onto the joint body, the diameter of the insertion port is reduced by the tapered threaded portion and the nut portion, so that the seal is sealed. The member strongly contacts the outer peripheral surface of the inner tube to obtain a sealing effect. On the other hand, after inserting the outer tube of the tubular body into the cylindrical groove of the socket, the outer tube is fixed to the socket by crimping the outer tube that faces the inner tube of the socket. That is, the inner tube is also fixed to the joint body and the socket due to the friction caused by the close contact between the outer tube and the inner tube, and the tube body obtains a predetermined pull-out strength. At this time, since the connecting part does not have an insert part that fits inside the pipe body as in the conventional case, there is no occurrence of liquid pooling, and the flow path resistance is also reduced, and pressure loss is also significantly reduced. In addition, since the structures for each function of the socket 1- are provided at both ends in the axial direction, the entire joint does not become bulky in the radial direction.

〔Example〕

Next, an embodiment of the present invention will be described based on FIGS. 1 and 2.

In these figures, 2 indicates a pipe body, and 4 indicates a pipe joint.

Among these, the tube body 2 includes an inner layer tube 2a made of plastic located at the innermost side, a pressure-resistant reinforcing layer 2b tightly wound around the outside of this inner layer tube 2a, and this reinforcing layer 2a.
It consists of a protective tube 2C made of plastic that is tightly fitted on the outside of b. The pressure-resistant reinforcing layer 2b and the protective tube 2C constitute an outer tube in this embodiment, and the pressure-resistant reinforcing layer 2b is made of braided metal wire, synthetic fiber, or the like.

On the other hand, the pipe joint 4 includes a joint body 6 made of synthetic resin, and a metal socket 8 that can be screwed onto one end of the joint body 6.
It is equipped with The joint body 6 has a tapered threaded portion 6a on its axial right end side (tube insertion direction side) into which the socket 8 is screwed, and further has a tapered threaded portion 6a on its axial right end side (tube insertion direction side).
Near the left end of is a nut part 6b and a screw part 6C for mounting.
is the provision. Further, a hollow portion 6d serving as a fluid flow path is provided inside the joint body 4 in the axial direction.
The tube insertion port 6e has an enlarged diameter. The height of the step 6f between the tube insertion port 6e and the hollow portion 6d is as follows:
The thickness is set to be approximately the same as the wall thickness of the inner tube 2a of the tubular body 2. Further, a fin-shaped sealing member 6g is integrally provided on the inner circumferential surface of the tube insertion port 6e, and is in contact with the outer circumferential surface of the inner tube 2a inserted into the insertion port. It has a well-known configuration as seen in No. 62-237192.

The socket 8 has a hollow part 8a in the axial center thereof into which the inner tube 2a of the tubular body 2 is inserted, and the left end side thereof is enlarged in diameter in a counterbore shape, and a connection hole 8 for the joint body 6 is formed.
It has become b. A nut (female thread) portion 8c that is screwed into the threaded portion 6a of the joint body 6 is formed on the side wall of this connection hole 8b.

Further, from the right end side to the center of the socket 8, a cylindrical groove 8d is formed from the end in the tube insertion direction into which the pressure-resistant reinforcing layer 2b and the protective tube 2c of the tube body 2 can be loosely inserted. At this time, by forming the cylindrical groove 8d, the end portion has a double cylindrical shape with an inner cylindrical portion 8e and an outer cylindrical portion 8f, and the outer cylindrical portion 8f is set to have a wall thickness that can be crimped. It is.

Next, the effects of the above embodiment will be explained.

First, after passing the tube 2 through the hollow part 8a of the socket 8, the protective tube 2C and pressure-resistant reinforcing layer 2b at the tip of the tube 2 are peeled off, leaving only the inner tube 2a at a depth corresponding to the tube insertion port 6e. Make it stick out by the length you want. Then, the inner tube 2a is inserted into the joint main body 6 from the tube body insertion port 6e while resisting the elastic force of the seal member 6g, and the distal end of the tube 2a is brought into contact with the step 6f as shown in FIG.

Next, the socket 8 is screwed onto the joint body 2.

As a result, since the threaded portion 6a and the nut portion 8C have a taper, radially inward pressure is applied to the tube insertion port 6e, and the diameter of the insertion port 6e is reduced. Therefore, the sealing member 6g comes into contact with the outer circumferential surface of the inner tube 2a with strong surface pressure, thereby obtaining a sealing effect against the fluid.

Next, if necessary, an axial cut of a predetermined length is made at the tips of the protective tube 2c and the pressure-resistant reinforcing layer 2b to enlarge the diameter, and this enlarged diameter portion is inserted into the cylindrical groove 8d of the socket 8. In this state, the outer cylindrical portion 8f of the socket 8 is crimped inward and clamped between it and the inner cylindrical portion 8e. Thereby, both the tubes 2C and the reinforcing layer 2b are connected to the joint body 6 via the socket 8 with high pull-out strength. Here, since the pressure-resistant reinforcing layer 2b and the inner layer tube 2a do not shift due to friction or engagement between the two, the inner layer tube 2a
a is connected to the joint main body 6 with a predetermined strength via the pressure-resistant reinforcing layer 2b and the protective tube 2C, so that high pull-out strength of the pipe body 2 can be obtained.

In this connected state, there is no difference in level caused by the conventional insert part for the flow path flowing through the tube body 2, so there is no accumulation of liquid, and as a result, there is no mixing when the transferred liquid is changed, and the Changes can be made easily and bacteria will not be generated at the connection points. Furthermore, as the effective cross-sectional area of the flow path becomes larger, the flow path resistance also becomes significantly smaller, resulting in a significant reduction in pressure loss. Therefore, the supply pressure of the fluid supply device that sends the fluid can be lowered, thereby making it possible to downsize the supply device and the pipe body 2.

Furthermore, in this embodiment, since the joint body 6 is made of synthetic resin, there is no eluate, making the joint suitable for transferring ultrapure water and the like.

In addition, in the above embodiment, the outer layer tube was composed of the pressure-resistant reinforcing layer 2b and the protective tube 2c.
Depending on the pipe pressure, only the protective tube 2c may be used as the outer layer tube, and in that case, the inner layer tube 2a
The high pull-out strength of the entire tubular body 2 is ensured by the friction between the protective tube 2c and the protective tube 2c. Further, in the above embodiment, the sealing member 6g having a fin-like cross section is used alone, but a plurality of this member 6g may be arranged in the axial direction, or the sealing member 6g having a fin-like cross section may be replaced. Any number of zero rings may be used.

〔Effect of the invention〕

As explained above, in the present invention, a pipe body having an inner layer tube and an outer layer tube is used, and the inner layer tube and the tube insertion port of the joint body are connected in a state where no liquid accumulates, and the socket is connected to the joint body. A radial pressing force is applied to the sealing member in the insertion port to seal the socket, and the outer tube is inserted into the cylindrical groove of the socket, and the outer circumferential surface of the groove is crimped to secure the outer tube and the inner layer. The entire tube body is connected with high pull-out strength due to friction and engagement between the tubes, and compared to fittings with conventional inserts, there is no possibility of bacteria forming due to liquid pooling, and there is no need to remove the liquid when changing the transferred liquid. This has the effect of eliminating mixing. Furthermore, pressure loss is also significantly reduced, and the supply pressure can be lowered by that amount, contributing to the downsizing of the fluid supply device. Another effect is that it is possible to reduce the manufacturing cost of the body.

In addition, since the joint body of this invention is made of synthetic resin, there is no eluate and no impurities are mixed into the transferred fluid.
Hence ultrapure water, chemicals, and paints.

It is suitable for transferring various liquids such as liquid foods where liquid accumulation in piping is undesirable.

Furthermore, in this invention, the socket has both a surface pressure adding structure and a tube body connection structure in the sealing function, and these are arranged at both ends in the axial direction, so the overall structure is simple while obtaining a high sealing effect and pull-out strength. In particular, the bulk of the joint in the radial direction perpendicular to the axial direction can be reduced, and the installation space of the pipe joint can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a partially broken side view showing the state of a pipe fitting and pipe body before connection according to an embodiment of the present invention, and FIG. 2 is a partially broken side view showing the state after connection in FIG. It is a diagram. In the figure, 2 is a pipe body, 2a is an inner layer tube, 2b is a pressure-resistant reinforcing layer, 2C is a protection tube, 4 is a pipe joint, 6 is a joint body,
6a is a threaded portion, 6e is a tube insertion port, 6g is a sealing member, 8 is a socket, 8C is a nut portion, 8d is a cylindrical groove, 8
e is an inner cylindrical portion, and 8f is an outer cylindrical portion.

Claims (1)

[Claims] (1) A pipe joint for connecting a pipe body having an inner layer tube and an outer layer tube covering the outside of the inner layer tube, the tube into which the inner layer tube can be inserted so that the inner hollow surface is almost flush with the tube. An insertion port is formed at the axial end, a tapered threaded portion is formed on the outer peripheral surface of the insertion port, and a sealing member that can come into contact with the outer peripheral surface of the inner layer tube is provided on the inner periphery of the tube insertion port. A joint body made of synthetic resin is provided on the surface side, a nut part is formed at one end in the axial direction to be screwed into the threaded part of the joint body to reduce the diameter of the tube insertion port, and the end of the outer layer tube is A metal socket having an insertable cylindrical groove bored at the other end in the axial direction, and an outer cylindrical part that forms the cylindrical groove of the socket with an inner cylindrical part can be crimped. A pipe joint featuring: