JP2524753Y2 - Resin pipe fittings for high-purity fluid transport piping - Google Patents

Description

[Detailed description of the invention]

[0001]

The present invention relates to the transfer of high-purity fluids such as high-purity liquids for semiconductor production and ultrapure water to various fluid devices such as valves, filters, pumps, flow meters, and tanks.
High-purity flow used when connecting piping for transport
The present invention relates to a resin pipe joint for body transportation piping .

[0002]

2. Description of the Related Art Conventionally, as this kind of pipe joint, one having a structure as shown in FIG. 5 is known. In this pipe joint, a seal part a1 having a tapered surface that gradually reduces inward in the axial direction is formed at an inlet of a socket of the joint body A into which the one end insertion part b1 of the pipe material B is inserted. Is trapezoidal peripheral wall f
Inserting part b1 of the inner ring F
Is press-fitted immediately adjacent to the inside of the joint body A, whereby the tube material B is locally bulged radially outward along the peripheral wall f to form a bulged portion b3. The female threaded part e1 of the press ring E is screwed and screwed to push the bulged part b3 and the inner ring F of the tube material B toward the joint body A side, thereby inclining the bulged part b3 on the pipe end side. The surface is pressed against the seal portion a1 to apply a sealing force.

[0003] Therefore, the tube material B is prevented from coming off by its bulging portion b3 being sandwiched between the seal portion a1 of the joint body A, the pressing portion e2 of the pressing wheel E, and the peripheral wall f of the inner ring F. The leakage of the fluid in B and the intrusion of foreign matter into the tube B are prevented by the sealing force generated when the tube end side inclined surface of the bulging portion b3 is pressed against the sealing portion a1.

[0004]

The conventional resin-made pipe joint having the above-mentioned structure is extremely easily softened when the fluid is at a high temperature because the inner ring F is directly exposed to the fluid. For this reason, the stress of the inner ring F is remarkably reduced, and the force of pressing the tube material B against the bulging portion b3 is reduced, so that the sealing force is lost and the fluid leaks.

Further, since the inner ring F is press-fitted into the tube material B, the smooth movement of the fluid tends to be hindered at the inner ring F portion. In particular, the outer surface of the peripheral wall f of the inner ring F and the bulging portion A phenomenon occurs in which the fluid stays in a small gap with the inner surface of b3. Therefore, it is unsuitable as a joint for a pipe for transporting a high-purity fluid such as a high-purity liquid or ultrapure water that requires smooth movement, and is restricted in use.

For this reason, the present applicant has already filed Japanese Utility Model Application No.
As disclosed in JP-A-69378 (Japanese Utility Model Laid-Open No. 2-117494), the inner ring has a socket for inserting the one-end insertion portion of a tube material whose diameter is increased by press-fitting an inner ring which does not hinder the movement of the fluid. A tubular joint main body having an external thread portion on an outer peripheral surface; a primary seal portion formed at a deep portion of the socket of the joint body and abutting against an inner end seal portion of the inner ring; A secondary seal portion abutting against an outer peripheral seal surface formed on the outer end side outer periphery of the inner ring and having a diameter reduced toward the tube end formed on the insertion portion outer periphery by a bulge formed on the outer end side outer periphery of the inner ring; A press ring which is screwed into an outer male screw portion of the joint main body and abuts the primary seal portion with the inner end seal portion and the secondary seal portion with the outer seal surface by screwing to apply a sealing force. proposed a resin <br/> fittings To have.

[0007] According to the resin pipe joint having the above-described structure, a strong sealing force is generated between the primary seal portion of the joint body and the inner end seal portion of the inner ring due to the screwing of the push ring. Since a pressing force in the axial direction is applied to the formed primary seal, stress relaxation due to temperature fluctuations (higher temperature) can be suppressed as much as possible at normal temperature, and the movement of the fluid is not hindered. Since the inner ring is press-fitted into the insertion portion of the tube, the cross section of the flow path becomes uniform, and the fluid can be smoothly moved without stagnation.
In addition, a strong sealing force is generated between the secondary seal portion of the joint body and the outer peripheral seal surface of the tube, and an axial pressing force is applied to the secondary seal, thereby relieving the stress similarly to the primary seal. Can be suppressed as much as possible. Therefore, the resin pipe joint proposed by the present applicant is a joint for high-purity transport piping such as high-purity liquid or ultrapure water .
It can be suitably used.

In the above-mentioned resin pipe joint, an inner ring having a swelling portion is press-fitted into a pipe material to achieve a secondary seal and has a pull-out strength. In order to improve the sealing performance and the pull-out strength, it is required to set a strict dimensional relationship between the pipe material and the inner ring on the premise that the sealing can be performed easily.

More specifically, the initial set tightening stress of the tightening portion for holding and holding the bulging portion of the inner ring press-fitted into the tube material is accompanied by repetition of softening and hardening of the resin during transport of the high-temperature fluid. Easy to change,
If the tightening portion is loosened due to such a change in the tightening stress, it is difficult to maintain necessary and sufficient pull-out strength and sealing performance as a pipe joint, and in that sense, the initial set tightening stress of the tightening portion is as small as possible. While smaller is preferable, if it is set to be smaller than necessary, the sealing performance between the inner ring and the joint body will be reduced. while pressed, Ri crucial technical matters der be properly set the initial tightening stress in the clamping portion between the predetermined sealing performance and draw resistance tubing and the inner ring in order to maintain, for the This type of resin pipe joint
In the hand, the basics that do not hinder the smooth movement of fluid
Sealing performance, pull-out strength and
To improve performance such as ease of press-fitting of inner ring
The thickness of the resin tubing and the thickness of the inner ring press fit
And the thickness of the bulge are very important factors.
You.

The present invention has been made in view of the above circumstances, and has the basic performance of not hindering the smooth movement of fluid.
While,-out <br/> press fit into reasonably easily tube the inner ring Rutotomoni, very small to ensure strong retaining function of the degree of though stress relaxation temperature variations of the fluid and the excellent sealing performance High purity flow that can be secured
And its object is to provide a resin pipe joint for body transportation pipeline.

[0011]

In order to achieve the above object, a resin pipe joint for a high-purity fluid transport pipe according to the present invention is a resin pipe member whose diameter is increased by press-fitting an inner ring which does not hinder the movement of fluid. A cylindrical joint body having a socket into which the one end insertion portion is inserted and having a male thread portion on the outer peripheral surface, a seal portion formed at one end of the joint body, and an outer end side of the inner ring An outer peripheral sealing surface formed on the outer periphery of the insertion portion of the tube material by a bulging portion formed on the outer periphery, the outer peripheral sealing surface being reduced in diameter toward a pipe end; In a resin-made pipe joint for a high-purity fluid transport pipe provided with a press ring that abuts a seal portion on a main body side and an outer peripheral seal surface on a tube material side and provides a sealing force, an end of the tube material extends along an axis. On the outer peripheral surface of the inner ring press-fitting part The extending portion to be wearing integrally formed,
In addition, the thickness of the press-fit portion of the inner ring is set to 1.2 to 1.5 times the thickness of the pipe material, and the thickness of the bulging portion is set to 1.2 times the thickness of the press-fit portion of the inner ring. ~ 2.0
It is set to double.

In the resin-made pipe joint for a high-purity fluid transport pipe having the above-described structure, it is preferable that an inclination angle of a seal surface of the seal portion on the joint body side with respect to an axis is set to 10 to 30 °.

[0013]

According to the present invention, the seal provided by applying a sealing force between the seal portion of the joint main body and the outer peripheral seal surface of the inner ring by the screwing of the push ring suppresses stress relaxation due to temperature fluctuation, and is excellent. sealing performance is ensured, also, since the inner ring is uniform is inserted addition unit indented in flow passage cross section to the tube, the residence of the fluid also Ri of no, smooth transfer of fluid
Demonstrate the basic performance of not hindering movement.

[0014] On top of that, sets the thickness of the press-fitting portion of the inner ring 1.2 to 1.5 times the thickness of the tube, the wall thickness of the expanded portion of the press-fitting portion of the inner ring By setting the thickness to 1.2 to 2.0 times the wall thickness , the bulging portion expands the diameter of the resinous tube at the time of press-fitting the inner ring into the tube.
Bonding chain of a molecule serving as a skeleton of the resin constituting the resinous tubular material
Is severed and creep occurs when transporting high-temperature fluids.
Eliminating the factors that lower the sealing performance, such as
That the inner ring can be easily press-fitted without difficulty.
In addition, in the press-fit state, the initial set tightening stress of the tightening portion where the tubing embraces and holds the bulging portion of the inner ring is reduced to reduce the stress relaxation accompanying the repetition of softening and hardening of the resin during transport of high-temperature fluid. The degree is extremely small, pull-out strength can be enhanced, and sealing performance is not much reduced.In addition, a straight extension integrally formed at one end of the pipe is extended along the axis on the outer peripheral surface of the press-fitting part of the inner ring. As a result, the sealing performance between the inner ring and the joint main body is favorably secured.

Further , a tree for a high-purity fluid transport pipe having the above configuration is provided.
In an oil-made pipe joint, the inner ring is reduced in diameter during screwing of the push ring by setting the inclination angle of the seal surface of the joint body side to the axis with respect to the axis at 10 to 30 ° to narrow the flow path cross section. , Without forming a bump-like convex part,
The surface pressure between the pipe and the fitting body is properly secured ,
It is possible to prevent deterioration due to stagnation of the fluid and decrease in purity while ensuring the performance .

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a high-purity fluid transportation according to an embodiment of the present invention.
It is a half sectional view of the resin pipe joint for transmission piping . In FIG. 1, resin pipe joints are, for example, PFA, PTFE, ETF.
It is composed of a joint body 1, an inner ring 2, and a pressing wheel 4 formed of a resin having excellent properties of chemical resistance and heat resistance such as E, CTFE, and ECTFE.

The joint body 1 is cylindrical, and has a first primary seal portion 11 crossing the axis Q formed at least at the end of the receiving port 10 at one end. Also, a secondary seal portion 12 crossing the axis Q is formed. A male screw portion 13 is formed on the outer periphery of the receiving port 10. The inner diameter of the receiving port 10 is formed to be larger than the inner diameter of the body portion 14, and the tapered surface that gradually decreases in diameter from the back end toward the outside in the axial direction and reaches the inner surface of the body portion 14 has a tapered surface. A first primary seal portion 11 is formed. On the other hand, the secondary seal portion 12 is formed by a tapered surface that gradually expands in diameter from the radial inner surface near the outer end of the receiving port 10 toward the outside in the axial direction and reaches the base of the male screw portion 13. That is, the secondary seal portion 12 is formed at the entrance of the receiving port 10.

The inner ring 2 has, at its inner end, a fitting portion 20 having an outer diameter capable of fitting into the socket 10 of the joint main body 1. A press-fit portion 21 having a small diameter corresponding to the wall thickness is formed continuously with the fitting portion 20 and has a sleeve shape as a whole. The inner diameter of the inner ring 2 is set to be the same as the inner diameter of the tube 5 and the inner diameter of the body 14 of the joint body 1 so as not to hinder the movement (flow) of the fluid. The inner end of the inner ring 2 has the first primary seal portion 1.
Inner end seal portion 2 formed of a tapered surface so as to abut against 1.
2 are formed.

On the other hand, the outer periphery of the outer end of the inner ring 2, that is, the outer periphery of the outer end of the press-fitting portion 21 gradually increases in diameter from the outer end toward the inner end in the axial direction. A tapered outer end seal portion 23 intersecting with the inner diameter of the outer end portion 2 is formed, and the diameter of the top portion of the outer end seal portion 23 is at least larger than the outer diameter of the press-fit portion 21 at the connection portion with the fitting portion 20. It is set to be large, and is larger than the outer diameter of the fitting portion 20 of the inner ring 2 in the illustrated example. That is, the large-diameter side of the outer end seal portion 23 is a bulged portion 24 having a mountain-shaped cross section formed on the outer peripheral surface on the outer end side of the inner ring 2. The tapered surface 25 that gradually decreases in diameter from the top of the bulging portion 24 toward the inner end of the inner ring 2 has an inclination angle that matches the inclination angle of the secondary seal portion 12 of the joint body 1 and an inner end. The seal part 22 is the first primary seal part 11
When the abutment is made, the gap between the secondary sealing portion 12 and the secondary seal portion 12 is formed to be equivalent to the wall thickness of the tube 5.

[0020] Here, as shown in FIG. 2, the resin pipe member 5
Assuming that the thickness of the inner ring 2 is a, the thickness of the bulging portion 24 of the inner ring 2 is b, and the thickness of the press-fitting portion 21 of the inner ring 2 is c, c = a × 1.2 to 1.5. And b = c × 1.2 to 2.0. Further, the inclination angle θ of the secondary seal portion 12 with respect to the axis Q
Is 10 to 30 °, and is set to 15 ° in this example.

At one end of the tube member 5, an extension portion 50A is formed integrally with the outer peripheral surface of the press-fit portion 21 of the inner ring 2 so as to extend by a length l along the axis Q thereof. It constitutes a part of the embedding unit 50.

The inner ring 2 is integrally connected to the tube 5 in a state where the press-fit portion 21 is press-fitted into one end of the tube 5 and its peripheral wall is enlarged. At this time, the enlarged diameter portion of the peripheral wall of the pipe member 5 becomes the insertion portion 50 inserted into the receiving port 10 of the joint body 1. When the insertion portion 50 is inserted into the receiving port 10, the inner end seal portion 22 abuts against the first primary seal portion 11 of the joint body 1 and the outer end seal portion 23 is inserted. The contact portion 50 is in contact with the inner surface of the inclined portion 51. Further, between the secondary seal portion 12 of the joint body 1 and the tapered surface 25 of the inner ring 2, a part of the insertion portion 50 of the pipe member 5 is sandwiched in an inclined state. That is, the outer peripheral surface of the tube material 5 deformed along the tapered surface 25 of the inner ring 2 becomes the outer peripheral seal surface 5 a and comes into contact with the secondary seal portion 12. The distal end of the extending portion 50A of the pipe member 5 is in contact with the step surface 20a of the press-fitting portion 21 of the inner ring 2.

The pressing wheel 4 has a female screw portion 41 screwed to the male screw portion 13 of the joint main body 1 on the inner peripheral surface of the cylindrical portion 40 and an annular end extending to the axial center at the outer end portion. Is formed. A pressing edge portion 43 is formed at the inner end of the pressing piece 42 on the inner surface side, and the pressing edge portion 43 is formed at the press-fit portion 2 of the inner ring 2.
The top of the one bulging portion 24 is, of course, set closer to the axis than the outer diameter of the portion adjacent to the fitting portion 20. The pressing wheel 4 thus constructed is connected to the inner ring 2 via the pipe member 5 and the joint body 1.
Side (details of the joint body 1 and inner ring 2)
Are pressed against each other), and the pipe 5 is connected to the joint body 1.
The joint body 1, the inner ring 2 and the tube member 5 are pressed against each other (specifically, the joint body 1 and the tube member 5 are pressed against each other) to hold the joint body 1, the inner ring 2 and the tube member 5 together and provide a sealing force.

In the pipe joint having the above-described structure, first, when the press-fitting portion 21 of the inner ring 2 is press-fitted into the end of the tubular material 5, the end of the tubular material 5 is enlarged as a whole, and the bulging portion 24 of the inner ring 2 is enlarged. Is the insertion port 50 whose diameter has been further expanded. Then, in this manner, the press-fit portion 2
The inner ring 2 and the one-end insertion portion 50 of the tube 5 are inserted into the receiving port 10 of the joint body 1 so that the inner end seal portion 22 contacts the first primary seal portion 11. The female member 41 of the press ring 4 which has been loosely fitted to the tube member 5 is screwed into the male screw portion 13 of the joint body 1, and the screw member is screwed and strongly tightened. Can be connected.

By connecting the pipe member 5 in this way, the insertion portion 50 of the tube member 5 is sandwiched between the press-fitting portion 21 of the inner ring 2 which cannot be moved in the axial direction and the joint body 1, and 2 outer end seal portion 23 and pressing wheel 4
Is also locally pinched by the pressing edge portion 43.
Therefore, the tube member 5 is held with a strong retaining force to prevent the tube member 5 from moving.

Further, when the pressing wheel 4 is screwed and strongly tightened, the first primary seal portion 11 of the joint body 1 and the inner end seal portion 22 of the inner ring 2 are pressed against each other, and a strong adhesive force is generated therebetween. . Also, in the resin pipe joint shown in FIG. 1, at the same time, the secondary seal portion 12 of the joint body 1, the outer peripheral seal surface 5a of the pipe member 5, the outer end seal portion 23 of the inner ring 2, and the second primary seal portion The inner surfaces of the inclined portions 51 of the tube 5 are also pressed against each other, and a strong sealing force is generated therebetween, and the outer and inner surfaces of the tube 5 are sealed on both surfaces. Therefore, in this resin pipe joint, the joint body 1
A so-called primary seal is formed between the inner ring 2 and the inner ring 2 and between the inner ring 2 and the pipe member 5 at the two places, thereby ensuring excellent sealing performance and preventing leakage of fluid or foreign matter. Intrusion can be reliably prevented.

Further, since a seal outside the flow path, that is, a so-called secondary seal is formed between the joint body 1 and the pipe member 5, even if a problem occurs in the primary seal due to creep or the like due to a heat cycle, This secondary seal prevents fluid leakage or foreign matter intrusion, and makes the seal extremely reliable. In addition, in the case of this resin pipe joint, an axial pressing force is applied by the cooperation of the joint body 1 and the pressing ring 4 in all three seal portions, so that the temperature of the fluid rises at normal temperature and of course. However, excellent sealability can be ensured by minimizing seal breakage due to stress relaxation.

Further, the inner diameter of the inner ring 2 is set to be the same as the inner diameter of the tube 5 and the inner diameter of the body 14 of the joint body 1 so as not to hinder the movement of the fluid. High-purity fluids such as high-purity liquids and ultrapure water can be secured because the cross-section of the road is uniform and excellent flow path characteristics can be ensured, allowing fluid to move smoothly without stagnation.
It can be used very suitably as a pipe joint.

By the way, the inner ring 2 is press-fitted into the tube member 5 to secure the pull-out strength by the bulging portion 24. The thickness b of the bulging portion 24 of the inner ring 2 and the thickness of the press-fitting portion 21 are increased. If the thickness c is smaller than the wall thickness a of the tube 5, the inner ring 2 may be reduced in diameter by press-fitting of the tube 5. In this regard, by setting the thickness c of the press-fit portion 21 of the inner ring 2 to be 1.2 to 1.5 times the thickness a of the tube 5, it is possible to withstand the press-in of the tube 5.
If it is larger than this size, the work of press-fitting the tube 5 becomes difficult. In other words, the mounting operation is facilitated by setting the above thickness.

The function of the secondary seal surface 5a is ensured by setting the thickness b of the bulging portion 24 to 1.2 to 2.0 of the thickness C of the press-fit portion 21 of the inner seal 2. In addition, it is possible to guarantee the pull-out strength for holding the pipe member 5 between the joint body 1 and the inner ring 2.

Further, the secondary sealing surface 5a is displaced in the axial direction by the screwing of the pressing wheel 4, and a sealing function is established. When the inclination angle θ of the sealing surface 5a is too large, the inner ring If the inclination angle θ is too small, an appropriate surface pressure cannot be obtained on the sealing surface 5a. On the other hand, when the inclination angle θ is set to 10 to 30 ° as described above, it is possible to secure a constant surface pressure of the seal surface 5a without fear of the inner ring 2 being reduced in diameter.

Incidentally, one end insertion portion 5 of the tube 5
3 is a shape as shown in FIGS. 3 and 4, when the cut surface of the tube 5 is not at a right angle, the step surface 20 a on the inner ring 2 side and the one end insertion portion 50 of the tube 5 are inserted. A gap G may form between the tip and the tip, adversely affecting the secondary sealing function. However, when the straight extension portion 50A is formed in the pipe member 5 as described above, it is assumed that some cap G exists between the tip of the extension portion 50 and the step surface 20a on the inner ring 2 side. Also, extension part 50A
As a result, the creepage distance 1 is increased, and the sealing performance is not reduced.

[0033]

As described above, according to the first aspect of the present invention, the wall thickness of the pipe, the press-fitting portion of the inner ring, and the bulging portion of the inner ring are formed.
By specifying the three dimensions of the wall thickness in relation to each other , fluid smoothness, which is the basic performance of this type of resin joint, is
One of the factors that lowers the sealing performance by easily and easily press-fitting the inner ring into the pipe material while ensuring excellent movement performance
Eliminates Creep Phenomena During High Temperature Fluid Transport
Together, very small degree of stress relaxation due to repetition of the softening and curing of the resin at the time of transportation of hot fluids by reducing the initial setting tightening stress of the clamping portion for holding narrowing enfold bulging portion of the inner ring tubing
As a result , the pull-out strength can be strengthened, the sealability is less reduced, and the straight extension integrally formed at one end of the tube material is closely adhered to the outer peripheral surface of the inner ring press-fitting portion along the axis for a long time. Therefore, even if a gap occurs between the tip of the one-end insertion portion of the pipe material and the step surface of the inner ring, the creepage distance can be increased to ensure good sealing performance between the inner ring and the joint body. it can. did
Therefore, it is extremely useful as a joint for high-purity fluid transport piping.
This has the effect of being able to be used effectively.

Further, according to the second aspect of the present invention, by specifying the inclination angle of the seal surface of the joint body side with respect to the axis of the seal surface, the inner ring is reduced in diameter when the push ring is screwed, and the flow path is reduced. Without reducing the cross-section or forming a bump-like projection, the sealing surface pressure between the pipe and the fitting body can be maintained properly to ensure the required sealing performance, and the deterioration and purity due to the stagnation of the fluid. it is possible to eliminate reduction, etc., high, such as high purity liquid, ultrapure water for semiconductor manufacturing
It can be used very effectively as a joint for purity fluid transport piping .

[Brief description of the drawings]

FIG. 1 is a half sectional view showing a resin-made pipe joint for a high-purity fluid transportation pipe according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram of a dimensional relationship of a main part of a resin pipe joint for a high-purity fluid transport pipe in the embodiment.

FIG. 3 is a perspective view in a case where one end insertion portion of the tube has no extension.

FIG. 4 is an enlarged sectional view of a main part of FIG.

FIG. 5 is a half-sectional view showing a conventional resin-made pipe joint for high-purity fluid transport piping .

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Joint main body 2 Inner ring 4 Press ring 5 Pipe material 5a Outer peripheral sealing surface 10 Reception port 11 Primary seal part 12 Secondary seal part 20a Stepped part 21 Press-fit part 22 Inner end seal part 24 Swelling part 50 Insertion part 50A Extension part a Thickness of pipe material b Thickness of bulging part c Thickness of press-fitting part Q Axis θ Secondary seal surface inclination angle

Claims (2)

(57) [Scope of request for utility model registration] 1. A tubular joint body having a socket into which one end insertion portion of a resin-made tubular material expanded by press-fitting an inner ring that does not hinder movement of a fluid, and having a male thread portion on an outer peripheral surface. The diameter of the pipe is reduced toward the pipe end formed on the outer periphery of the insertion portion of the pipe material by a seal formed at one end of the joint body and a bulge formed on the outer circumference of the outer end of the inner ring. An outer peripheral sealing surface, and a press ring which is screwed into the outer peripheral male thread portion of the joint main body and which abuts the sealing portion on the joint main body side and the outer peripheral sealing surface on the tube material side by screwing to provide a sealing force. In the resin-made pipe joint for high-purity fluid transport piping, an extension part extending along the axis at one end of the pipe material and closely contacting the outer peripheral surface of the press-fitting part of the inner ring is integrally formed, and the press-fitting part of the inner ring is formed. The wall thickness is 1.2 to 1 of the wall thickness of the tube. And the thickness of the bulging portion is set to 1.2 times the thickness of the press-fitting portion of the inner ring.
High-purity fluid characterized by being set to 2.0 times
Resin pipe fittings for transportation piping . 2. The resin-made pipe joint for high-purity fluid transport piping according to claim 1, wherein an inclination angle of the seal face of the seal portion on the joint body side with respect to an axis is set to 10 to 30 °.