JP4298497B2 - Stainless steel fittings for resin tubes - Google Patents

Description

  The present invention relates to a stainless steel joint for resin tubes used in a semiconductor manufacturing apparatus.

In semiconductor manufacturing equipment, fluids such as clean air, pure water, temperature-controlled water, and organic chemicals are used. Resin tubes such as fluororesin tubes, polyurethane tubes, and nylon tubes are used for the pipes that carry these fluids. Stainless steel fittings are used for fittings that connect these resin tubes, taking oil and impurity measures into consideration. Is used. Currently, stainless steel joints of double ferrule type are frequently used as resin tube joints.
The following Non-Patent Document 1 includes a joint body having an insert part, a sleeve that is movably provided outside the insert part, and a nut that is screwed into the joint body to move the sleeve, A bulging portion is provided on the outside, and a tube is inserted into the insert portion, and a nut is screwed into a joint body to move the sleeve to the outside of the bulging portion to press and lock the tube. Joints are described.
Nitta Moore Co., Ltd. Brochure “Chemfit CS Series”

The use of the double ferrule-type stainless steel joint described in the background art for an extremely soft resin tube has the following problems.
(A) Since the reaction force of the tube cannot be expected, the holding force of the ferrule tube is weak, the tube easily rotates, and the tube pulling resistance is low.
(B) In order to solve the above problem (a), a tube insert is also used, but in this case, there is a possibility that the tube may be cut by the penetration of the ferrule.
(C) Since the tightening amount of the nut for tightening the ferrule is the number of rotations from the finger tightening position of the nut, in the case of a tube, the tightening amount is unclear.
(D) The number of parts is 4 (joint body, nut, front ferrule, back ferrule), which takes time to manage and handle.
(E) If there are two ferrules and the mounting order is wrong, there is a risk of fluid leakage and tube disconnection.
The pipe joint described in the latter part of the background art has a problem that, when inserting the sleeve into the nut, the direction of inserting the sleeve is wrong, or the sleeve falls depending on the connection direction with the pipe.
The present invention has been made to solve the above-described problems, and an object thereof is to provide an inexpensive resin tube joint in which a resin tube can be easily and reliably connected.

The present invention includes a joint body having an insert portion, a sleeve, and a nut that is screwed into the joint body to press the sleeve, and the insert portion has an outer diameter that is substantially the same as the inner diameter of the resin tube to be inserted. The outer surface and a protrusion having an outer diameter larger than the outer surface are provided, and the sleeve is provided with an inner surface having an inner diameter slightly larger than the outer diameter of the tube to be inserted, and the tube is inserted into the insert portion, In a pipe joint where a nut is screwed into the joint body to move the sleeve, and the tube is pressed and locked between the insert part and the sleeve.
The outer surface of the sleeve is formed with a step portion composed of a large diameter portion and a small diameter portion, and the length of the small diameter portion is such that the end surface of the small diameter portion protrudes outside the nut when the sleeve is inserted into the nut. The inner diameter of the end face is widened so that the nut and the sleeve are integrated. As a result, free rotation of the sleeve within the nut and prevention of separation (separation) from the nut can be achieved.

(A) The stainless steel joint according to the present invention is easy to manage and handle because the number of parts is integrated into two parts (joint body, assembly nut).
(B) Since the assembly nut according to the present invention can be easily manufactured, it is excellent in cost.
(C) In the present invention, by expanding the inner diameter of the end face of the sleeve, it becomes easy to insert the tube, and further, it is possible to prevent the tube from being damaged by the swing of the tube.
(D) Since the tightening amount of the nut is determined at a position where it abuts against the joint body, the tightening amount becomes clear.
(E) Since the tube is prevented from being pulled out by crimping the tube between the sleeve and the insert portion, the holding force of the tube is strong, and there is no danger of cutting the tube because there is no biting point.

The best mode for carrying out the present invention will be described based on an embodiment with reference to the drawings.
A stainless steel joint according to an embodiment of the present invention includes a joint body 1, a sleeve 2, and a nut 3, as shown in FIG.
The joint body 1 is composed of a male screw portion 4 to be screwed into a device or the like, a spanner hanging portion 5, and a pipe connecting portion 6 for connecting a resin tube 9. The side surface of the spanner hanging portion 5 is a facing surface that faces the side surface of the nut 3 described later. In addition, although the structure on the opposite side to the pipe connection part 6 is made into the external thread part, it is not limited to it, It can be set as a socket part, a pipe connection part, etc. As shown in FIG. 2, the pipe connecting portion 6 includes a male screw portion 7 into which the nut 3 is screwed, and an insert portion 8 extending in the axial direction from the end surface of the male screw portion 7. The insert portion 8 is cylindrical and has an outer diameter that is substantially the same as the inner diameter of the resin tube 9. In the vicinity of the center, a protrusion 8a having a trapezoidal cross section is formed in the circumferential direction. The resin tube 9 can be inserted into the insert portion 8 up to the end surface of the male screw portion 7.
The sleeve 2 has an inner surface having an inner diameter slightly larger than the outer diameter of the resin tube 9, and an inclined surface that extends outward is formed on the left side of the inner surface in the drawing. On the outer surface of the sleeve 2, there is formed a stepped portion having a large diameter portion 2a on the male screw side and a small diameter portion 2b on the opposite side. The outer diameter of the large diameter portion 2a is smaller than the inner diameter of the female screw of the nut 3. Has been.
The nut 3 has an internal thread portion that is screwed into the internal thread portion 7 of the joint body 1 on the inner surface thereof, and an inner diameter that is slightly larger than the outer diameter of the small diameter portion 2 b of the sleeve 2, and is engaged with the step portion of the sleeve 2. Thus, a pressing portion 3a that allows the sleeve 2 to move toward the male screw portion 7 is formed.
The length of the small-diameter portion 2 b of the sleeve 2 is set such that the end surface of the small-diameter portion 2 b of the sleeve 2 protrudes outside from the pressing portion 3 a of the nut 3 when the sleeve 2 is inserted into the nut 3. . By expanding the inner diameter of the end face by pressing, free rotation of the sleeve 2 in the nut 3 and removal (separation) from the nut 3 can be prevented.
In a state where the assembly nut in which the nut 3 and the sleeve 2 are integrated is screwed into the male screw portion 7 of the joint body 1 and the side surface of the nut 3 is in contact with the side surface of the spanner hooking portion 5 of the joint body 1, The protruding portion 8 a having a trapezoidal cross section of the insert portion 8 and the large diameter portion 2 a of the sleeve 2 are opposed to each other with the resin tube 9 interposed therebetween.
Next, a method for connecting the stainless steel joint for resin tube and the resin tube will be described.
(A) Selection of joint and resin tube Depending on the type of joint and the inner and outer diameters of the tube 9 to be used, an assembly nut consisting of the joint body 1, the nut 3 and the sleeve 2 is selected. The resin tube 9 is cut at a right angle with a sharp blade at its connection side end.
(B) Insertion of resin tube With the assembly nut inserted into the tube 9, the tube 9 is inserted into the insert portion 8 of the joint body 1, and the end surface of the tube 9 comes into contact with the end surface of the male screw portion 7 of the joint body 1. Like that.
(C) After moving the assembly nut to the joint body 1 side and manually tightening the nut 3 to the male threaded portion 7 of the joint body 1, the side surface of the assembly nut is the side surface of the spanner hanging portion 5 of the joint body 1 with a spanner. Tighten until it hits. At this time, the spanner span 5 of the joint body 1 is fixed with a backup spanner. Thereby, the proper tightening amount of the nut 3 is obtained. The resin tube 9 is pressed between the protruding portion 8 a of the insert portion 8 and the sleeve 2, and is sealed and locked to the joint body 1.
(D) Reuse of joint body and assembly nut After loosening the assembly nut and removing the resin tube 9 from the insert part 8 of the joint body 1, cut again at a right angle at the position where the deformed part of the end face of the resin tube 9 is removed. By reusing the devices after the above (b), they can be reused.

The following test was performed using the stainless steel joint for resin tubes according to the present invention.
(A) Tube size used: φ4 × φ2.5, φ6 × φ4, φ8 × φ6, φ12 × φ8, φ18 × φ12
Material: Polyurethane, Teflon (registered trademark) , Nylon (b) Airtight test N2 gas, no leakage at 2 times the tube operating pressure (visual).
There is no He (1.5 MPa) leak from the joint by repeated bending.
(C) No problem until elongation of the tensile test tube or at 200 N or more.
(D) No breakage until internal pressure breakage tube breakage.

It is a partial cross section figure of the stainless steel joint for resin tubes by this invention. It is the A section enlarged view of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Joint body 2 Sleeve 2a Large diameter part 2b Small diameter part 3 Nut 3a Press part 4, 7 Male thread part 5 Spanner hook part 6 Pipe connection part 8 Insert part 8a Protrusion part 9 Resin tube

Claims (3)

A joint body (1) having an insert portion (8), a sleeve (2), and a nut (3) that is screwed into the joint body (1) and presses the sleeve (2), the insert portion (8) ) Is provided with an outer surface having an outer diameter substantially the same as the inner diameter of the resin tube (9) to be inserted, and a protrusion (8a) having an outer diameter larger than the outer surface, and is inserted into the sleeve (2). An inner surface having an inner diameter slightly larger than the outer diameter of the tube (9) is provided, the tube (9) is inserted into the insert portion (8), and a nut (3) is screwed into the joint body (1). In the pipe joint that moves the sleeve (2) and presses and locks the tube (9) between the insert (8) and the sleeve (2),
On the outer surface of the sleeve (2), a stepped portion comprising a large diameter portion (2a) and a small diameter portion (2b) is formed. The length of the small diameter portion (2b) is such that the sleeve (2) is a nut (3 ) In such a state that the end surface of the small diameter portion (2b) protrudes outward from the nut (3), and the inner diameter of the end surface is expanded to integrate the nut (3) and the sleeve (2). Stainless steel joint for resin tubes, characterized by   In a state where the sleeve (2) and the nut (3) are integrated, the nut (3) is screwed into the joint body (1), and the side surface of the nut (3) is hooked with the spanner of the joint body (1). The protrusion (8a) of the insert portion (8) and the large-diameter portion (2a) of the sleeve (2) are opposed to each other in a state of being in contact with the side surface of the portion (5). The stainless steel joint for resin tubes according to claim 1.   The nut (3) has an inner diameter slightly larger than the outer diameter of the female screw portion (7) of the joint body (1) and the small diameter portion (2b) of the sleeve (2) on its inner surface. A stainless steel joint for resin tubes according to claim 1 or 2, wherein a pressing portion (3a) is formed which engages with a step portion of the sleeve (2) to move the sleeve (2). .

Images