JP2549943Y2 - Resin pipe fittings - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a fluid pipe such as a pipe for supplying high-purity liquid or ultrapure water for semiconductor production to fluid equipment such as various valves, filters, pumps, flow meters and tanks. Regarding resin pipe fittings used when connecting
More specifically, the present invention relates to a resin-made pipe joint having a characteristic of exhibiting excellent sealing performance irrespective of fluid temperature fluctuation.

[0002]

2. Description of the Related Art FIG. 5 shows a conventional pipe joint of this type. This pipe joint forms a seal portion a1 having a tapered surface whose diameter gradually decreases inward in the axial direction at the entrance of the socket a of the joint body A into which the one end insertion portion b1 of the pipe material B is inserted, An inner ring F having a peripheral wall f having a trapezoidal cross section is press-fitted immediately adjacent to the inside of the insertion portion b1 of the tubular material B, whereby the tubular material B is locally bulged radially outward along the peripheral wall f. To form the bulging portion b3, and screw the female screw portion e1 of the pressing ring E into the male screw portion a2 at one end of the joint main body A, and screw the bulging portion b3 and the inner ring F of the tube material B. It is configured to press against the joint body A side and press the pipe end side inclined surface of the bulging portion b3 against the sealing portion a1 to apply a sealing force.

[0003] Therefore, the swelling portion b3 of the tube material B is sandwiched between the sealing 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, so that the tube material B is prevented from coming off. The external leakage of the fluid in the pipe B and the invasion of foreign matter into the pipe B are prevented by the sealing force generated when the pipe end side inclination of the bulging portion b3 is pressed against the seal 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 B against the bulging portion b3 is reduced, so that the sealing force is lost and the fluid leaks. Especially, pressing wheel E
The inner ring F also contracts and deforms toward the inner diameter side due to the tightening, and a reduction in sealing force due to this also causes leakage.

Further, since the inner ring F is press-fitted into the tube B, the smooth movement of the fluid tends to be hindered at the inner ring F. 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 piping for high-purity liquid or ultrapure water, which requires smooth movement, and is restricted in use.

For this reason, the present applicant has already filed Japanese Utility Model Application No.
According to No. -69378, the inner ring which does not hinder the movement of the fluid is press-fitted.
Inserted into the one end receiving port of the joint body formed in a cylindrical shape, abuts the cross-shaped primary seal portion and the inner end sealing portion of the inner ring to the axis formed in the back of the receiving port, The inner ring is formed at the entrance of the receiving port on the outer peripheral sealing surface which is reduced in diameter toward the pipe end formed on the outer periphery of the insertion portion by being pressed by the bulging portion formed on the outer peripheral side of the outer end portion. The secondary seal portion in a crossing shape is brought into contact with the axis line, and the sealing force is applied to one end of the joint body by screwing to the primary seal portion and the inner end seal portion, and to the secondary seal portion and the outer peripheral seal surface. It proposes the one that the pressing wheel to give is screwed.

[0007] According to the above-mentioned resin pipe joint proposed by the present applicant, 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 by the screwing of the push ring. Since the pressing force in the axial direction is applied to the primary seal formed in this manner, stress relaxation due to temperature fluctuation (high temperature) can be suppressed as much as possible at normal temperature, and fluid movement can be suppressed. Since the inner ring that does not hinder the insertion is pressed into the insertion portion of the tube material, 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, this pipe joint can be suitably used as a pipe joint for high-purity liquid or ultrapure water.

In the above-mentioned resin pipe joint, the inner seal fitting portion is fitted into the socket of the joint main body, and the secondary seal is pressed by reverse taper between the primary seal portion and the inner end seal portion. However, in order to strengthen the sealing function on the flow path side and reliably suppress liquid pool, a strict dimensional relationship between the primary seal part on the joint body side and the inner end seal part on the inner ring side Is required to be set.

In the above-mentioned resin pipe joint,
In the situation where stress is constantly acting on each resin component, the resin softens when transporting a high-temperature fluid under such conditions, and cures at room temperature. Stress relaxation of the resin component occurs. In particular, the inner seal portion of the inner ring and the corresponding primary seal portion formed at the back of the joint body are originally difficult to obtain close contact. When the inner ring is strongly pressed and pressed in due to advancement, not only is the problem that stress concentrates on the edge part of the inner part of the socket and it is easy to break from that edge part, but also the higher the adhesion, the higher the temperature fluctuation There is a problem that the phenomenon of stress relaxation is remarkable, and the sealing performance at the primary seal portion is reduced.

The present invention has been made in view of the above circumstances, and reliably maintains the sealing performance at the primary seal portion irrespective of fluid temperature fluctuations in a predetermined assembled state, and effectively exerts a liquid accumulation suppressing action. It is an object of the present invention to provide a resin-made pipe joint that can prevent damage due to stress concentration.

[0011]

Means for Solving the Problems To achieve the above object, a resin pipe joint according to the present invention has a receptacle into which a one-end push-in portion of a tube material expanded by press-fitting an inner ring is inserted. A tubular joint main body having an external thread portion on an outer peripheral surface, a primary seal portion formed in an inner portion of a receiving portion of the joint main body so as to intersect with the axis line, and an inner end seal portion of the inner ring abutting; A resin-made pipe joint which is screwed to an outer male screw portion of the main body and is provided with a seal portion at the inner portion of the socket and a pressing ring for applying a sealing force to an inner end seal portion of the inner ring by screwing the inner ring portion. innermost end of the fitting portion is chamfered, the inner end of the socket of the fitting body is formed on the tracks surface, and the inner end of the primary sealing portion and the inner ring of the socket side of the joint body corresponding thereto Inclination angle of seal before press-fitting / contact There together is set to 5 to 10 °, in which the sealing surface width of said primary seal portion is set smaller than equal to or a seal surface width of the inner end sealing portion.

[0012]

According to the present invention, stress relaxation due to temperature fluctuation is suppressed by the sealing by the sealing force between the primary seal portion at the back of the joint body and the inner end seal portion of the inner ring due to the screwing of the push ring. You.

[0013] Further, since the inclination angle difference between the primary seal portion of the inner portion of the receiving port and the inner end seal portion of the inner ring before press-fitting and abutment is set to 5 to 10 °, the two seal portions abut. When this is done, stress concentrates near the inner end of the primary seal portion and the contact surface pressure is increased, so that reliable prevention of liquid pool is achieved, and the seal surface width of the primary seal portion is changed to the inner end seal surface width. Since it is as follows, it does not protrude toward the joint body at the time of press-fitting and abutment, guarantees uniformity of the cross section of the flow path, and can prevent stagnation of the fluid.

[0014] In particular, the innermost end chamfer of the fitting portion of the inner ring, from the rear end of the socket of the joint body is formed on the song surface, when pressed press-fitting the inner ring by screwing the junk ring In addition, it is possible to prevent the breakage due to the concentration of stress on the edge portion of the inner portion of the receiving portion, and to set the adhesion force between the primary seal portion of the inner portion of the receiving portion and the inner end seal portion of the inner ring to be small. The phenomenon of stress relaxation due to temperature fluctuation in the part can be greatly reduced, and the sealing performance in the primary seal part can be improved.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a half sectional view of a resin pipe joint according to an embodiment of the present invention. In FIG. 1, resin pipe joints are, for example, PFA, PTFE, ETFE, CTFE, ECTF.
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.

The above-mentioned joint body 1 is cylindrical, and has a first primary seal portion 11 crossing the axis Q at least at the inner end of the receptacle 10 at one end thereof. 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 inner end toward the outside in the axial direction to the inner surface of the body portion 14 is formed by the taper 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 a fitting portion 20 having an outer diameter which can be fitted to the socket 10 of the joint body 1 at an inner end thereof, and a pipe material near the connecting portion with the fitting portion 20 is formed of a pipe material. The press-fit portion 21 having a small diameter corresponding to the thickness of
To form a sleeve 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. At the inner end of the inner ring 2, an inner end seal portion 22 formed of a tapered surface that abuts the first primary seal portion 11 is formed.

The primary seal portion 11 of the joint body 1 on the receiving port 10 side and the inner end seal portion 2 of the fitting portion 20 of the inner ring 2
As shown in FIG. 2, the inclination angle α before press-fitting / contact
It is set to 5-10 °. Assuming that the seal surface width of the primary seal portion 11 is W1 and the seal surface width of the inner end seal portion 22 is W2, the relationship between the two is set to W2 ≧ W1.

As shown in FIG. 2, the innermost end 20a of the fitting portion 20 of the inner ring 2 is chamfered.
It is formed on a curved surface having a curvature of 25 to 0.5.

The clearance G between the inner peripheral surface of the socket 10 of the joint body 1 and the outer peripheral surface of the fitting portion 20 of the inner ring 2 is set to -1 to 0.3 mm. If the clearance G is too large, the inner ring 2 becomes large due to thermal cycling or the like, which adversely affects the sealing performance. Therefore, it is desirable that the clearance G be as small as possible as described above to the extent that press-fitting is possible.

On the other hand, the outer circumference of the outer end of the inner ring 2, that is, the outer circumference 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 seal portion 23 intersecting the inner diameter of the outer seal 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 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.

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 pipe 5 deformed along the tapered surface 25 of the inner ring 2 becomes the outer peripheral seal surface 5a, and the secondary seal portion 12
Abut.

The above-mentioned pressing wheel 4 is provided on the inner peripheral surface of the cylindrical portion 40 with the female screw portion 4 screwed to the male screw portion 13 of the joint body 1.
1 is formed, and an annular pressing piece 42 extending toward the axial center is formed at the outer end. A pressing edge portion 43 is formed at the inner end of the pressing piece 42 on the inner surface side. The position where the pressing edge 43 is formed is set to be more axial than the outer diameter of the portion adjacent to the fitting portion 20 as well as the top of the bulging portion 24 of the press-fitting portion 21. The pressing wheel 4 thus configured presses the inner ring 2 toward the joint body 1 via the tube member 5 (specifically, presses the joint body 1 and the inner ring 2 together) and presses the tube member 5 toward the joint body 1 ( Specifically, the joint body 1 and the pipe member 5 are pressed against each other) to hold the joint body 1, the inner ring 2 and the tube member 5 in an integrally connected state, and to apply a sealing force.

In the resin pipe joint having the above structure, first,
When the press-fitting portion 21 of the inner ring 2 is press-fitted into the end of the tube 5, the end of the tube 5 expands as a whole, and the position corresponding to the bulging portion 24 of the inner ring 2 further increases the diameter of the insertion port 50. Becomes Then, the inner ring 2 and the one-end insertion portion 50 of the tube 5 into which the press-fit portion 21 is press-fitted into the end portion of the tube 5 are inserted into the receiving port 10 of the joint body 1 and the inner end seal portion 22 is formed. The female threaded part 41 of the press ring 4 which is brought into contact with one primary seal part 11 and then loosely fitted to the pipe member 5 in advance is screwed into the male threaded part 13 of the joint body 1, and this is screwed and strongly tightened. The pipe member 5 can be connected to the joint body 1.

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 ring 4 is screwed and strongly tightened, the first primary seal portion 11 of the joint main 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 Inclined part 5 of pipe material 5
The inner surfaces 1 are also pressed against each other to generate a strong sealing force therebetween, and the outer and inner surfaces of the tube 5 are sealed on both surfaces. Therefore, in this resin-made pipe joint, a so-called primary seal inside the flow path is formed between the joint body 1 and the inner ring 2 and at two places between the inner ring 2 and the pipe member 5, which is excellent. It is possible to reliably prevent leakage of fluid or intrusion of foreign matter by ensuring sealing performance.

Further, since a so-called secondary seal outside the flow path 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 problem may occur. The secondary seal prevents fluid leakage or foreign matter intrusion, making the seal extremely reliable. In addition, in the case of this resin-made pipe joint, the pressing force in the axial direction is applied to all three seal portions by cooperation of the joint body 1 and the press ring 4, so that not only the fluid at normal temperature but also the fluid Even at high temperatures, seal breakage due to stress relaxation is suppressed as much as possible, and excellent sealing properties can be ensured.

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. Since the cross section of the road becomes uniform and the flow path characteristic for smoothly moving the fluid without stagnation can be secured, it can be suitably used as a joint for a high-purity liquid or ultrapure water pipe.

Incidentally, in order to improve the primary sealing function and surely reduce the liquid pool, it is necessary to locally increase the sealing contact surface pressure on the flow path side (inner diameter side). For this reason, in the primary seal, the primary seal portion 11 of the joint body 1 and the inner end seal portion 2 of the inner ring 2 are provided.
2 with the inclination angle difference α of 5 to 10 °, the fitting portion 20 of the inner ring 2 is
If brought into contact with the inner end sealing portion 22 and the primary sealing portion 11 is press-fitted to 0, as shown in FIG. 3, the primary sealing portion 11
The stress concentrates in the vicinity of the inner end portion 11a, and the contact pressure increases. Therefore, it is possible to effectively exhibit the effect of suppressing liquid pool on the inner diameter side.

At this time, if the inner diameter γ1 of the joint main body 1 and the inner diameter γ2 of the inner ring 2 are the same and the above-mentioned inclination angle difference α is provided, the primary seal portion 1 is pressed and abutted as shown in FIG.
There is a possibility that the inner end 11a of the first member protrudes toward the inner diameter side. However, as described above, the relationship between the seal surface width W1 of the primary seal portion 11 and the seal surface width W2 of the inner end seal portion 22 of the inner ring 2 is set so as to satisfy W2 ≧ W1.
By selecting and setting, it is possible to eliminate the possibility that the inner end 11 protrudes toward the inner diameter side.

If the innermost end 20a of the fitting portion 20 of the inner ring 2 remains edge-shaped, the tightening force of the pressing ring 4 causes this portion 20a to be moved to the inner end of the socket 10 of the joint body 1. There is a risk of being damaged by being pressed against 10a. In this regard, the innermost end 20a is chamfered, and
The inner end 10a of the 0 is also formed into a curved surface having a suitable curvature, thereby preventing stress concentration on the innermost end 20a even when receiving the tightening force of the pressing wheel 4, thereby preventing breakage from the innermost end 20a. it can.

[0032]

As described above, according to the present invention, not only can it be suitably used as a joint for a pipe for ultrapure water, but also the primary seal portion at the back of the socket on the joint body side and the inner seal side can be used. By setting the inner end seal part to specific conditions, when the primary seal part at the back of the socket and the inner end seal part of the inner ring come into contact with each other, stress is generated near the inner end part of the primary seal part. The contact surface pressure is concentrated and the liquid pool suppressing effect can be effectively exerted by increasing the contact surface pressure, and the seal surface width of the primary seal portion is set to be equal to or less than the inner end seal surface width, so that the joint body at the time of press fitting and contact Without protruding to the side, it is possible to guarantee the uniformity of the cross section of the flow path and prevent the fluid from staying.

In addition, since the innermost end of the fitting portion of the inner ring is chamfered and the corresponding rear end of the socket of the joint body is formed in a curved surface, the screwing of the push ring is performed. When the inner ring is pressed and press-fitted, it is possible to reliably prevent breakage due to stress concentration on the edge part of the inner part of the receiving port, while maintaining the primary seal part of the inner part of the receiving port and the inner end sealing part of the inner ring. By setting the contact force of the seal member to be small, the phenomenon of stress relaxation due to temperature fluctuation in the seal portion can be extremely reduced, and the sealing performance at the primary seal portion can be significantly improved.

[Brief description of the drawings]

FIG. 1 is a half sectional view showing a resin pipe joint according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram of a dimensional relationship of a primary seal portion of a resin pipe joint in the embodiment.

FIG. 3 is an explanatory diagram of a proper sealing state when an inner sealing portion on an inner ring side abuts on a primary sealing portion on a joint body side.

FIG. 4 is an explanatory view of a defective sealing state when an inner end sealing portion on an inner ring side comes into contact with a primary sealing portion on a joint body side.

FIG. 5 is a half sectional view showing a conventional resin joint.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Joint main body 2 Inner ring 4 Press ring 5 Tube material 5a Outer peripheral sealing surface 10 Reception port 10a Reception end of primary port 11 Primary seal part 12 Secondary seal part 20 Fitting part 20a Inner end of fitting part 24 Swelling part 50 Pushing part W1, W2 Seal surface width Q axis α inclination angle difference

Claims (1)

(57) [Scope of request for utility model registration] 1. A tubular joint body having a socket into which a one-end push-in portion of a tube material expanded by press-fitting of an inner ring is inserted, and having a male thread portion on an outer peripheral surface, and a socket of the joint body having a male screw portion. A primary seal portion formed in an inner side of the inner ring of the inner ring so as to intersect with the axis, and a primary seal portion which is screwed to an outer peripheral thread portion of the joint main body and which is screwed to seal the inner portion of the receiving portion; In a resin-made pipe joint provided with a portion and a pressing ring for applying a sealing force to an inner end seal portion of the inner ring, an innermost end of the fitting portion of the inner ring is chamfered, and a corresponding receiving portion of the joint body is formed. inner end of the mouth is formed songs <br/> surface, and the inclination angle difference before press fitting, abutting the inner end sealing portion of the primary sealing portion and the inner ring of the socket side of the joint body is 5 to 10 ° And the seal of the primary seal portion Resin pipe fitting, wherein a width is set smaller than the seal surface width equal to or greater in the inner end sealing portion.