JP2881577B2 - Tube fitting - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a cleaning solution such as pure water,
In addition, the present invention relates to a tube joint suitable as a joint for a tube made of a fluororesin that controls a flow conduit for a chemical solution or the like.

[0002]

2. Description of the Related Art Conventionally, as this type of tube joint,
For example, there is one disclosed in Japanese Utility Model Laid-Open No. 4-122882.

[0003] In this conventional technique, an outer flange and a large-diameter portion are formed at the end of a fluororesin tube, and the large-diameter portion is formed in a tube joint in which a tube is formed to have a deformed portion to prevent the tube from coming off. The insertion cylinder of the joint body having a groove ring in the diameter portion was inserted, and a large part of the ring loosely inserted in the large diameter portion was inserted into the groove ring and screwed into the male screw portion of the joint body. The ring is tightly pressed against the outer flange with a cap nut to prevent the tube from coming off, and the inner part of the shoulder of the cap nut presses the middle part of the tube tightly to the end face of the insertion tube to bend the tube. This is a tube joint formed by:

[0004]

In the prior art, the step of a thermal operation for forming a deformed portion in a tube is required twice, which is time-consuming. The shape of the collar will not be even,
In some cases, imbalance occurs at the time of tightening, and stable tightening cannot be performed, and skill in heating is required.

Further, after the large diameter portion is formed, the tube bending portion gradually shrinks with time after the mold is removed, and the tube refraction portion does not sufficiently enter the insertion tube, so that heat remains in the large diameter portion. Since it has to be quickly pushed into the insertion tube of the joint, there are many problems that agile work is required.

According to the present invention, in order to eliminate the above-mentioned problems, an enlarged diameter portion is formed near an end of a fluororesin tube, and a low-melting fluororesin inner ring is sandwiched as a welding material outside the expanded portion. Weld the outer ring made of high melting point fluorine resin,
An object of the present invention is to prevent the tube from coming off by pressing the projecting end of the inner ring tightly with a screw input of a cap nut screwed into the joint body.

[0007]

SUMMARY OF THE INVENTION An object of the present invention described above is to provide a tube joint in which a tube is formed with an enlarged diameter portion and a ring is attached to the outside of the tube to prevent the tube joint from falling off. On the outer peripheral surface of the tube enlarged portion obtained by expanding the vicinity of the end of a heat-resistant fluororesin tube generally referred to as PTFE having a high melting point and usually referred to as PTFE, which is generally referred to as PFA having a lower melting point than the tube. While covering the inner ring made of resin, further covering the outer ring of the same material as the tube on the outer peripheral surface of the ring, by heating the outer ring, the inner ring is heated to the melting point or more by the conduction heat thereof,
A joint surface between the tube enlarged portion and the inner ring and a joint surface between the rings are fixed with a welded portion, respectively, and an insertion cylinder of a joint body having a groove ring is inserted into the tube enlarged portion. Also, by inserting most of each ring into the groove ring and tightening the protrusion of the inner ring with a cap nut screwed into a male screw portion of the joint body, the inner ring and the tube diameter increase. This can be achieved by tightly pressing each end of the tube ring to the bottom of the groove ring and tightly pressing the bent portion of the tube enlarged-diameter portion to the front end of the insertion tube at the hole edge of the shoulder of the cap nut.

Further, as a material for the tube and each ring, the outer peripheral surface of a tube enlarged portion obtained by expanding the vicinity of an end portion of a tube made of a fluororesin called relatively PFA having a relatively low melting point is provided on the outer peripheral surface. The inner ring made of the same material as the tube is covered, and the outer peripheral surface of the ring is further covered with an outer ring having a higher melting point than that of the tube, which is generally called PTFE, and has a higher heat-melting affinity. The inner ring may be heated to a temperature equal to or higher than its melting point by heat to weld the joint surface between the tube enlarged portion and the inner ring and the joint surface between the rings. In addition, the thickness of the protruding portion of the inner ring may be formed to be thin, and the outer ring may be formed with an inner flange for receiving the tip of the tube enlarged portion.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments will be described with reference to the drawings. First, as shown in FIG. 1, the basic structure of the present invention is to form a tube joint in which a tube is formed to have a diameter-enlarged deformation portion and a ring is attached to the outside of the tube joint to prevent the tube from falling off. FIG. 2 shows the vicinity of the end of a tube 1 made of a fluororesin having a relatively high melting point and heat resistance such as tetrafluoroethylene (PTFE) as shown in FIG.
As shown in FIG. 3, the tube is forcibly pushed into the slope C of the TFE expanding jig A to expand the diameter, and the tube expanding portion 1 a and the tube bending portion 1 are expanded.
b is made as shown in FIG.

Next, as shown in FIG. 4, an inner ring 2A made of a fluororesin having a melting point lower than that of the tube 1 and usually made of fluororesin is put on the outer peripheral surface of the enlarged diameter portion 1a as a welding material as shown in FIG. Further, a reinforcing outer ring 2B made of the same material as that of the tube 1 is covered as shown in FIG. By heating the outer ring 2B from the outside with a heating ring heater h as shown in FIG. 5, the inner ring 2A is heated to the melting point or more by the conduction heat transmitted in the thickness direction to expand the tube. The joint surface between the diameter portion 1a and the inner ring 2A and the joint surface between the rings 2A and 2B can be fixed to each other with a welded portion a as shown in FIG.

Next, as shown in FIG. 6, the insertion tube 5 of the joint body 4 made of a fluororesin having the groove ring 3 in the tube enlarged-diameter portion 1a is inserted, and most of the rings 2A and 2B are removed. It is inserted into the groove ring 3 as shown in FIG. Then, the protruding portion 2a of the inner ring 2A is tightened with the cap nut 6 screwed into the male screw portion 4a of the joint body 4 as shown in FIG.
And the bent portion 1b of the tube enlarged-diameter portion 1a was tightly pressed against the tip of the insertion tube 5 by the hole edge of the shoulder portion 7 of the cap nut 6. As a result, the tube joint according to the present invention could be configured.

In particular, the inner ring 2A made of a low melting point fluorocarbon resin interposed between the tube enlarged diameter portion 1a and the outer ring 2B in the present invention is an outer ring heated from a ring heater h via a ceramic heat transfer spacer S. 2B, the molten resin is uniformly melted by the conduction heat transmitted uniformly in the thickness direction, and this molten resin permeates well into the tube expansion portion 1a made of heat-resistant fluororesin and the outer ring 2B, and is then cooled and solidified. As a result, a strong welded portion a was formed, and the force of preventing the ring from coming off the tube could be enhanced.

Therefore, due to this strong welded portion a,
The tube enlarged portion 1a, which is immovable due to the tightening force of the cap nut 6 on the protruding portion 2a of the welded inner ring 2A firmly fixed to the tube enlarged portion 1a, and is fusion-fixed to the tube enlarged portion 1a. The outer ring for reinforcement 2B, which is fixed to the inner ring 2A with a strong welded portion a and immovable, and the edge of the hole of the shoulder portion 7 of the cap nut 6 is pressed against the insertion tube 5 of the tube bending portion 1b. The tube 1 has a total of three immovable portions with the Chu bending portion 1b immobilized by force.
As shown in FIG. 1, the airtightness and liquid tightness of the joint body 4 are strictly maintained, and the joint is tightly connected to the joint body 4, so that the joint body 4 does not loosely loosen or be pulled out.

The projecting portion 2a of the inner ring 2A is slightly thinned so that the thinned projecting portion 2a is appropriately loosened when the cap nut 6 is "tightened" due to aging of the tube bending portion 1b. "Retightening" can be performed without applying unnecessary external force to the enlarged diameter portion 1a.

If the inner flange 2b for receiving the tube enlarged-diameter portion 1a is formed at the tip of the outer ring 2B as shown in FIG. 9, the welding position of the inner ring 2A to the tube 1 can be easily adjusted, and the tube 1 The tip of the enlarged diameter portion 1a can be protected.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention can be realized by the following examples of the material of the tube 1 and the inner and outer rings 2A and 2B used in the present invention. That is, the vicinity of the end of a tube 1 made of a fluororesin having a relatively low melting point, such as a tetrafluoroethylene / perfluoroalkylvinylether copolymer (commonly referred to as PFA) (ethylene tetrafluoride / perfluoroalkoxyethylene copolymer resin), is used. An inner ring 2A made of the same material as the tube 1 is provided on the outer peripheral surface of the expanded tube portion 1a obtained by expanding the diameter.
The ring 2A is further covered with a poly.
A heat-resistant outer ring 2B such as tetra-fluoro-ethylene is covered, and by heating the outer ring 2B, the inner ring 2A is heated to the melting point or more by the conduction heat,
The joint surface between the tube enlarged-diameter portion 1a and the inner ring 2A and the joint surface between the rings 2A and 2B may be welded at the welding portion a in the same manner as described above.

[0017]

As described above, the present invention has the following advantages. The inner ring 2A made of a low-melting-point fluorocarbon resin interposed between the tube enlarged-diameter portion 1a and the outer ring 2B in the tube joint according to the first and second aspects of the present invention is formed by removing the heat-resistant affinity outer ring 2B from the heated outer ring 2B. Melts evenly with conduction heat evenly transmitted in the thickness direction,
This molten resin permeates well through the tube enlarged diameter portion 1a made of fluororesin and the outer ring 2B, and then is cooled and solidified to obtain a strong welded portion a.

Therefore, due to the strong welded portion a,
The tube enlarged portion 1a, which is immovable due to the tightening force of the cap nut 6 on the protruding portion 2a of the welded inner ring 2A firmly fixed to the tube enlarged portion 1a, and is fusion-fixed to the tube enlarged portion 1a. The outer ring for reinforcement 2B, which is fixed to the inner ring 2A with a strong welded portion a and immovable, and the edge of the hole of the shoulder portion 7 of the cap nut 6 is pressed against the insertion tube 5 of the tube bending portion 1b. The tube 1 has a total of three immovable portions with the Chu bending portion 1b immobilized by force.
The first is that the airtightness and liquid tightness of the joint body 4 are strictly maintained, and the joint body 4 is tightly connected to the joint body 4 so that the joint body 4 is not loosened or pulled out and can be used safely for a long period of time.
Has the effect of

Further, in the present invention, the forming of the tube bending portion 1b, the expanding of the expanded diameter portion 1a, and the welding of the inner and outer rings 2A, 2B to the outer peripheral surface thereof can be realized in one process. There is also a second effect that shortening has become possible.

The outer ring 2B has a poly-tetra-
Since a heat-resistant ring such as fluoroethylene is used, the ring heater h as a heating source is connected to the outer ring 2B.
The outer ring 2B conducts heat evenly in the direction of its thickness, so that the inner ring 2A having a low melting point is evenly and evenly higher than its melting point. The molten resin can be heated and penetrates well into the enlarged diameter portion 1a of the tube 1 including the outer ring 2B, and becomes a solid welded portion a by being cooled and solidified, and the rings 2A, 2B withdraw from the tube 1. There are the third and fourth effects that the prevention force can be increased and the uneven heating due to the convection of the surrounding air can be reduced.

Further, after the heating and welding are completed, the contracted force of the enlarged diameter portion 1a of the tube 1 to return to the original size can be firmly received by the welded rings 2A and 2B. There is also a work benefit that it is not necessary to carry out insertion of haste.

According to the third aspect, the protrusion 2a of the ring 2
Is slightly thinner than other places, so that the tube bending portion 1b
When the "tightening" of the cap nut 6 due to the secular change, the "thickening" can be performed without applying unnecessary external force to the large-diameter deformed portion 1a of the tube 1 by loosening the thinned protrusion 2a appropriately. The effect could be added.

According to the fourth aspect, the insertion depth of the outer ring 2B into the tube 1 can be automatically determined by the inner flange 2b.
A practical benefit that the fusion residue of the tube enlarged portion 1a does not adhere to the diameter increasing jig A and molding is easy can be added.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional side view of a tube joint according to the present invention.

FIG. 2 is a sectional view showing a preparation state of tube expansion.

FIG. 3 is a vertical cross-sectional side view showing a process of expanding a tube.

FIG. 4 is a longitudinal side view showing a relationship among a tube, a diameter increasing jig, and a heating ring heater.

FIG. 5 is a longitudinal side view in a state different from FIG. 4;

FIG. 6 is a longitudinal sectional side view showing a state in which a tube is being joined to a tube joint.

FIG. 7 is a longitudinal sectional side view in a state different from FIG. 6;

8 is a vertical sectional side view of the one shown in FIG. 7 in the process of tightening the cap nut.

FIG. 9 is a longitudinal side view of an embodiment in which an inner collar is formed on a ring.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Fluororesin tube 1a Tube expansion part 1b Tube refraction part 2A Inner ring made of low melting point fluororesin (inner ring for welding material made of PFA) 2B Outer ring made of heat resistant fluororesin (outer ring for reinforcement made of PTFE) 2a Projection Part 2b Inner flange 3 Groove ring 3a Groove ring bottom 4 Joint body 4a Male screw part 5 Insertion cylinder 6 Cap nut 7 Shoulder A A large-diameter jig C A large-diameter jig of a large-diameter jig h Heat source (ring heater for heating) ) S Heat transfer spacer

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) F16L 17/00-19/08 F16L 29/00-35/00 F16L 41/00-49/00

Claims (4)

(57) [Claims] 1. A tube joint made of a tube having a relatively high melting point and heat resistance, which is formed of a tube having a relatively high melting point and heat resistance. An outer ring 2A made of a fluororesin having a melting point lower than that of the tube 1 is placed on the outer peripheral surface of the tube enlarged portion 1a obtained by expanding the diameter in the vicinity of the end, and the outer surface of the inner ring 2A is further covered with the tube. The outer ring 2B is covered with the outer ring 2B, and by heating the outer ring 2B, the inner ring 2A is heated to a temperature equal to or higher than its melting point by the conduction heat, so that the joining surface between the tube enlarged-diameter portion 1a and the inner ring 2A is joined. And the joining surfaces of the rings 2A and 2B are welded to a
And the insertion tube 5 of the joint body 4 having the groove ring 3 is inserted into the tube enlarged-diameter portion 1a, and most of the rings 2A and 2B are inserted into the groove ring 3. By tightening the protrusion 2a of the inner ring 2A with the cap nut 6 screwed into the male screw 4a of the joint body 4,
The distal ends of the inner ring 2A and the enlarged tube portion 1a are tightly pressed against the bottom 3a of the groove ring 3, and the bent portion 1b of the enlarged tube portion 1a is connected to the edge of the shoulder 7 of the cap nut 6. A tube fitting tightly pressed against the tip of the insertion tube 5 with. 2. A tube joint having a tube with a relatively low melting point made of a fluororesin having a relatively low melting point formed in a tube joint having an enlarged diameter portion formed on a tube and a ring attached to the outside thereof to prevent the tube from falling off. An inner ring 2A made of the same material as the tube 1 is put on the outer peripheral surface of the tube enlarged portion 1a obtained by expanding the diameter, and the outer peripheral surface of the inner ring 2A is further higher in melting point and heat resistance than the tube 1. The inner ring 2A is heated to a temperature equal to or higher than its melting point by the heat of the outer ring 2B.
a and the contact surface between the inner ring 2A and each of the rings 2A,
The joint surfaces of the joints 2B are fixed to each other by welding portions a, and the insertion cylinders 5 of the joint body 4 having the groove rings 3 are inserted into the tube enlarged diameter portions 1a.
Is inserted into the groove ring 3 and the protruding portion 2a of the inner ring 2A is tightened with the cap nut 6 screwed into the male screw portion 4a of the joint body 4 to thereby form the inner ring 2A.
Each of the distal ends of the tube enlarged diameter portion 1a and the tube enlarged diameter portion 1a is tightly pressed against the bottom 3a of the groove ring 3, and the bent portion 1b of the tube enlarged diameter portion 1a is inserted into the insertion tube by the hole edge of the shoulder portion 7 of the cap nut 6. Tube joint tightly pressed against the tip of 5. 3. The tube joint according to claim 1, wherein the thickness of the projection 2a of the inner ring 2A is reduced. 4. The tube enlarged diameter portion 1a is attached to an outer ring 2B.
The tube joint according to claim 1, 2 or 3, wherein an inner flange (2b) is formed to receive the tip of the tube.