JP2000046262A - Pipe coupling and its connecting method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a weldless, gasketless, or non dead space pipe coupling to prevent the occurrence of pollution, in a pipe coupling used in a piping field for comparatively a low pressure gas and a liquid and a vacuum piping field. SOLUTION: After a nut 8 is inserted in a pipe 2 having a groove 14 previously formed in the vicinity of a pipe end, a sleeve 11 having a tip in which a plurality of slits 13 are formed is inserted and the tip 12 of the sleeve is fitted in the groove 14. A pipe assembly is inserted in a coupling body 1 having a protrusion part 3 formed on the inner side and having size equal to the inside diameter of a pipe. The nut 8 is fastened against the coupling body 1 to curve the sleeve 11 and through the spring properties thereof, a pipe end face 5 is butted against the side face 4 of the protrusion part 3 to apply a surface pressure between metal surfaces to seal internal fluid.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to pipe joints, and more particularly to the field of relatively low-pressure gas or liquid pipes such as high-purity gas pipes for semiconductor manufacturing, edible beverages, sanitary pipes for medical use, and vacuum pipes. It relates to pipe fittings used in the field.

[0002]

2. Description of the Related Art FIG. 5 is an axial sectional view of a metal gasket seal pipe joint used for a high-purity gas pipe for semiconductor production. As shown in the figure, the metal gasket seal pipe joint is inserted through the female nut 21 and the nut 2 through a thrust washer 22.
A female nut weld gland 24 having a flange portion 23 abutting on the first step portion, a male nut 25 screwed into the female nut 21, and inserted through the male nut 25 to be inserted into the tip of the nut 25; It is composed of a male nut weld gland 27 having a flange 26 to be abutted, and a metal gasket 29 held via a holder 28 so as to be located on the distal end surface of the flange portion 23 of the female nut weld gland 24. I have. The pipes are welded to the tubular portions of the weld glands 24 and 27, respectively.

In the above-mentioned pipe joint, by screwing a male nut 25 into a female nut 21, both flange portions 23, 2 are formed.
6 are connected via a metal gasket 29,
The connection between the fitting and the pipe and the sealing of the internal fluid are performed.

FIG. 6 is an axial sectional view of a sanitary pipe joint used for sanitary piping. As shown in the figure, the sanitary fitting has two ferrules 32 each having a tapered flange 31 and a tapered flange 3.
A gasket 33 attached to a depression at the tip end surface of
It comprises a flange 34 having a tapered groove which engages with both tapered flanges 31. In addition, piping is welded to both ferrules 32, respectively.

[0005] By tightening the two tapered flanges 31 with the flanges 34, the distal end surfaces of the two tapered flanges 31 are connected via a gasket 33, thereby connecting the pipe joint to the pipe and sealing the internal fluid.

[0006]

In a conventional metal gasket-sealed pipe joint used for high-purity gas pipes for semiconductor production, dust from the metal gasket and contamination of the inside of the pipe due to welding cause a reduction in semiconductor production yield. There is a problem that the gas replacement property is deteriorated due to the decrease and dead space.

In addition, sanitary pipe joints used for sanitary pipes are also problematic in that gasket causes the taste to be transferred, the smell is transferred to the product due to deterioration or damage, and the dead space deteriorates the automatic cleaning characteristics. In the sanitary fittings, the concept of easy disassembly and assembly has been adopted, and no measures have been taken against the deterioration and contamination of gaskets due to cleaning steam and sterilizing chemicals even today when automatic cleaning has been generalized. It should be noted that, although different from the application fields described above, bite pipe joints are widely used in the field of hydraulic piping. This pipe joint is composed of a joint body, a nut, and a ferrule provided between the joint body and the nut. By screwing the nut into the joint body, the ferrule is squeezed along the tapered surface of the joint body, and the tip bites into the pipe. , For connecting the pipe joint to the pipe and sealing the internal fluid. In the case of this pipe joint, since the joint body and the pipe end face do not have a structure that seals the internal fluid, when this pipe joint is used in the above-mentioned application fields, dead space and the applicable pipe are limited to a small diameter. There is a problem.

[0008] The present invention relates to a pipe joint used in the field of relatively low-pressure gas or liquid pipes such as high-purity gas pipes for semiconductor production, edible beverages, sanitary pipes for medical use, or the field of vacuum pipes. Weldless, for prevention
It is an object of the present invention to provide a gasket-less pipe joint with zero dead space.

[0009]

The present invention has solved the above-mentioned problems as follows. That is, after inserting a nut into a pipe in which a groove has been machined in the vicinity of the pipe end, insert a sleeve having a plurality of slits at the tip, insert the sleeve tip into the groove, and assemble the pipe. It is inserted into the joint body having a step inside the inside of the pipe, and the sleeve is bent by tightening a nut on the joint body. Apply pressure to seal the internal fluid.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described based on embodiments with reference to the drawings.

FIG. 1 is an axial sectional view of a pipe joint according to the present invention. In the figure, what is indicated by reference numeral 1 is a joint main body. A step portion (projection) 3 having an inside diameter equal to the inside diameter of the pipe 2 to be inserted is provided at the center of the inside of the joint body 1, and a pipe end face 5 can be brought into contact with a side surface 4 of the step portion 3. Have been. Screws are cut on both sides on the outside of the joint body 1, and a spanner hook 6 is provided in the center. In addition, tapered surfaces 7 are formed on both sides of the joint body 1 toward the inside.
Are formed. The joint body 1 is mainly made of a material having corrosion resistance and may be covered with Teflon or the like.

A nut 8 is screwed into each of the two screws of the joint body 1, and a step 9 having an inner diameter slightly larger than the outer diameter of the tube is provided at an inner end of the nut 8. A tapered surface 10 is formed inward on the inner side surface.

A sleeve 11 having a curved cross section is provided between the joint body 1, the nut 8 and the pipe 2. The sleeve tip 12 has a smaller diameter than the outer diameter of the tube.
As shown in the figure, a plurality of slits 13 are cut to the center position. Since the sleeve tip 12 is easily expanded by the slit 13, the sleeve tip 12 can be easily attached to a groove 14 formed near the pipe end, which will be described later. At the rear end of the sleeve 11,
Tapered surface 1 in contact with tapered surface 10 of nut 8
5 are formed.

In the circumferential direction of the outer periphery near the pipe end, a groove 14 is provided.
Is processed in advance. If possible, it is necessary to process the pipe end face 5 at the same time with a dedicated processing machine with high accuracy.

As shown in FIG. 3, the groove 14 is desirably a groove having a letter-shaped cross section. However, the present invention is not limited to this. Any groove having a surface 14a perpendicular to the axial direction of the tube 2 can be used. Good. Next, a method for connecting the pipe joint and the pipe will be described.

Prior to inserting the tube 2 into the joint body 1, a nut 8 and a sleeve 11 are inserted into the tube 2 in this order, and a sleeve end 12 is fitted into a groove 14 of the tube 2. This tube assembly is inserted into the joint body 1, a spanner is hung on the spanner hook 6, and the nut 8 is tightened to an appropriate value until the sleeve 11 is further bent. By this tightening, the pipe end face 5 is pressed against both side faces 4 of the step portion 3 of the joint main body 1 to generate a surface pressure, and sealing is performed so that the internal fluid does not leak.

The sleeve 11 curved by the tightening
Plays a role of a spring, so that in the actual piping, a constant sealing surface pressure can always be applied while avoiding a change in the sealing surface pressure due to expansion and contraction due to heating and cooling of the tube 2.
If necessary, a gasket made of a material suitable for the purpose can be interposed between both side surfaces 4 of the step portion 3 and the tube end surface 5 to further enhance the sealing ability.

In the above embodiment, the nut 8 and the sleeve 11 are fitted into the pair of pipes 2 and this pipe assembly is inserted into both sides of the joint body 1 so as to face each other. However, as shown in FIG. An end 16 having the same shape as one end of the joint body 1
It is good also as a structure which forms a and inserts the said pipe assembly there.

That is, in the present invention, the joint main body includes one formed on equipment or the like.

[0020]

Since the present invention is constructed as described above, it can be used in the field of relatively low-pressure gas or liquid pipes such as high-purity gas pipes for semiconductor manufacturing, edible beverages, sanitary pipes for medical use, etc. Pipe fittings used in the field of piping can be weldless, gasketless, and zero dead space pipe fittings.

[Brief description of the drawings]

FIG. 1 is an axial sectional view of a pipe joint according to the present invention.

FIG. 2 is a development view of a sleeve of the pipe joint according to the present invention.

FIG. 3 is a view showing a shape of a groove to be machined near a pipe end;

FIG. 4 is an axial sectional view of a pipe joint according to another embodiment.

FIG. 5 is an axial sectional view of a metal gasket seal pipe joint used for a conventional high-purity gas pipe for semiconductor production.

FIG. 6 is an axial sectional view of a sanitary pipe joint used for a conventional sanitary pipe.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Joint main body 2 Pipe 3 Step part 4 Side surface 5 Pipe end surface 6 Spanner hook part 7 Tapered surface 8 Nut 9 Step part 10 Tapered surface 11 Sleeve 12 Sleeve tip (tip) 13 Slit 14 Groove 14a Surface 15 Tapered surface 16 Equipment 16a End

Claims (5)

[Claims] 1. A joint body (1) having a stepped portion (3) equal to the inner diameter of the pipe on the inside and a tapered surface (7) formed on a side surface, and screwed into the joint body (1) on the inside. A nut (8) having a threaded portion and a stepped portion (9) slightly larger than the outer diameter of the pipe, and a tapered surface (10) formed on the inner surface of the stepped portion (9); And between the nut (8) and the pipe (2), the two tapered surfaces (7, 10).
The sleeve (11) has a plurality of slits (13) cut at its tip (12), and has a groove (1) pre-processed near the pipe end.
4), the tube end surface (5) is brought into contact with the side surface (4) of the step portion (3) of the joint body (1) by the spring property due to the curvature of the sleeve (11), and the surface between the metal surfaces is formed. A pipe joint characterized by applying pressure. 2. The pipe joint according to claim 1, wherein the sleeve tip has a diameter smaller than an outer diameter of the pipe. 3. The slit (13) is provided with a sleeve (1).
The pipe joint according to claim 1 or 2, wherein the pipe joint is cut to the center position of (1). 4. The pipe joint according to claim 1, 2 or 3, wherein a side surface (4) of the step portion (3) of the joint body (1);
A gasket is interposed between the pipe end faces (5), and the pipe end face (5) is attached to the side surface (4) of the step portion (3) of the joint body (1) by the resiliency of the sleeve (11). A pipe joint characterized by applying a surface pressure by contacting through a pipe. 5. After inserting a nut (8) into a pipe (2) in which a groove (14) is formed in advance near the pipe end, the tip (1) is inserted.
A sleeve (11) provided with a plurality of slits (13) is inserted into 2), and a sleeve tip (12) is inserted into a groove (1).
4) Insert the pipe assembly into a joint body (1) having a step (3) inside having a step (3) equal to the inside diameter of the pipe, and tighten a nut (8) to the joint body (1) to sleeve (11).
Characterized in that the tube end face (5) is brought into contact with the side surface (4) of the step portion (3) by a spring property to apply a surface pressure between the metal surfaces to seal the internal fluid. Connection method of the joint.