JPH0341285A - Coupling - Google Patents

Abstract

PURPOSE:To completely avoid fluid leakage by composing a coupling of a coupling body comprising a thread section at one end and a protrusion section at the other end, a tightener having slits, and a cap threadedly fitted to the tightener. CONSTITUTION:A coupling comprises a coupling body 1, tightener 2, and cap 3. The coupling body 1 is provided with a thread section 1a threadedly fitted to a body to be attached at one end, and a protruded section 1b at the other end, and a lock section 1c preventing the tightener 2 from rotating. The tightener 2 has a thread section 2a and is provided with slits 2b for expanding itself. A cap 3 is provided with a thread section 3b threadedly fitted to the thread section 2a of the tightener 2 and edge section 3a for connecting the cap 3 to the tightener 2 and pushing and pressing the tube 4 inserted into the coupling body against the protrusion section 1b to firmly fix the tube 4 to the coupling body 1. As a result, the leakage caused by creep phenomenon can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a plastic fluid coupling used in piping systems for transferring high-temperature, high-pressure deleterious fluids, mainly in so-called high-tech fields such as semiconductors.

[Prior Art and its Problems] As coupling mechanisms for plastic pipes (including tubes), seal-proof taper screws, use of ferrules, and various other seal-proof structures are known.

However, for example, TFE (polytetrafluoroethylene), PFA (copolymer of polytetrafluoroethylene and perfluoroalkyl vinyl ether), F
Due to the characteristics of fluororesins such as EP (polytetrafluoropropylene copolymer), the liquid used is often high temperature and high pressure, which is harmful, and causes factors such as repeated expansion and contraction due to thermal cycles and cleavage. This may cause fluid leakage.

This is mainly due to the occurrence of minute gaps at the joint due to the above factors, and it is extremely difficult to prevent this. Therefore, in the conventional 11-move system, fluid temperature 120'C2 pressure 2
It is forced to be used under conditions of about Kg/c1 or less.

[Means for Solving the Problems] The present invention includes a joint including a cylindrical joint body, a fastener that fits into the joint body, and a cap that screws into the fastener, and the main body includes: One end has a threaded part that screws into the object to be attached, such as equipment, and the other end has a convex part, and between the threaded part and the convex part there is a fastener that fits on the outer periphery of the joint body. A latching part is provided to prevent rotation, and the fastener has a threaded part formed on its outer peripheral surface, and a slit that expands when the fastener is fitted into the joint body is formed in the axial direction, and the cap has a threaded part on its inner circumferential surface that is screwed into the threaded part of the fastener, and an edge on the inside of the upper end, and when the cap that threads into the fastener is fastened, the edge of the cap and the fastener are connected. This method attempts to solve the above-mentioned conventional problems by pressing the tube inserted into the outer periphery of the joint body at the upper end against the convex part of the body to tightly fix the tube to the joint body attached to equipment, etc. It is.

[Function] In the joint according to the present invention, the plastic tube that is inserted through the convex part of the i-hand body to the latch part is connected to the edge of the cap by tightening the cap that is threaded onto the fastener. The upper end is pressed against the convex part of the fitting body, which firmly fixes it to the main body attached to equipment, etc., and prevents leakage even if the fluid temperature and pressure conditions are within an allowable range that significantly exceeds the temperature and pressure conditions of conventional fittings. It is possible to realize an extremely reliable plastic joint without any occurrence of such problems.

[Embodiments of the Invention] The present invention will be described in detail based on the drawings. 1 to 4 are diagrams showing one embodiment of the present invention.

In the figure, A is a joint, and this joint A is composed of a joint body 1 made of TFE (tetrafluoroethylene resin), a fastener 2 also made of TFE, and a cap 3 made of TFE (also made of TFE). Note that 4 is a tube made of PFA (a copolymer resin of tetrafluoroethylene and perfluoroalkyl vinyl) attached to the joint A.

As shown in FIG. 2, the joint body 1 has a cylindrical shape as a whole, and has a threaded portion 1a at one end and a convex portion lb at the other end. A hooking portion 1c is provided at the end of the threaded portion 1a to serve as a stopper when the joint is screwed onto equipment.

The convex portion 1b has a substantially circular cross section. The locking portion 1c also has a groove 1c for fitting a locking piece 2c, which will be described later.
1 is formed, while a pair of opposing flat portions 1c2, 1c2 are formed on the side wall to facilitate tightening with a spanner or the like. Note that ld is the outer peripheral wall of the joint body l between the convex part 1b and the hooking part 1c, and a fastener 2, which will be described later, is attached to this part.
or mated.

The fastener 2 has a cylindrical shape as shown in 3rd U:jJ, and has a threaded portion 2a formed on its outer peripheral surface and an abutment portion 2d formed on its upper end surface. Note that 2b is a slit for expanding the fastener 2 when fitting the fastener 2 to the outer peripheral wall 1d of the joint body 1. Furthermore, the end surface of the abutting portion 2d is tapered, making it easy to abut the tube 4 attached to the spherical convex portion 1b. Reference numeral 2C denotes a locking piece provided at the end of the threaded portion 2a, that is, the lower end of the fastener 2, which is fitted into the aforementioned lcl to prevent the fastener 2 from rotating.

As shown in FIG. 4, the cap 3 has a cylindrical shape, and has a hole 3b formed on its inner circumferential surface to be screwed into the threaded portion 2a of the fastener 2. An overhanging edge 3a is formed.

Next, the action will be explained.

First, the fastener 2 is assembled to the joint body 1 in advance, and then the joint body 1 is screwed into a screw hole of equipment using a spanner or the like using its flat portion 1d. Next, heat the tube 4 with a burner etc. to the softening temperature.
0'C~160℃) This is passed through the convex part 1b to the hooking part 1c.
Install the coating all the way to the end face. As the tube cools, it contracts and is firmly fixed.

Then, the cap 3, which has been attached to the tube in advance, is screwed onto the fastener 2.

As the cap 3 rotates, the fastener 2 gradually rises and comes into contact with the tapered surface of the abutting portion 2d or the tube 4 of the convex portion 1b. In this way, the tube 4 is firmly fixed to the joint A by being pressed and held by the edge 3a and the abutting portion 2d at the convex portion 1b. As shown in Fig. 1, the joint between the inner surface of the joined tube 4 and the joint body 1 is smooth, and unlike conventional joints, the end faces are joined, so there is no difference in level, etc., and there is no fluid flow. When a pulling force is applied due to internal or external pressure, creep may occur in the threaded portion, creating a gap between the tube and the fitting body and causing leakage. Even if the portion 3b extends and the tightening force of the edge 3a decreases, the abutment portion 2d and the convex portion ib maintain a seal, so fluid leakage never occurs.

In addition, in the above embodiment, the fastener 2 was attached by expanding the slit, or the fastener 2 may be divided into two parts, or the fastener 2 may be assembled by pressing the heat-softened elastomer without providing a slit. In addition, in the above embodiment, the joint body 1 is fixed to equipment,
For example, when connecting tubes to each other, the joint body 1 is formed vertically symmetrically around the hook IC, and the fasteners 2 are fitted on both sides of the joint body 1. The tube is fastened with the upper and lower caps 3. In this case, it goes without saying that a groove 1cl into which the locking piece 2C fits is formed on both sides of the locking part 1c.Furthermore, in the above embodiment, the joint A is made of a resin material, but it goes without saying that it may be made of a metal material. It is.

[Effects of the Invention] The present invention provides a joint that completely prevents leakage due to the creep phenomenon, which is a major drawback of conventional plastic joints, and can be used safely even with deleterious fluids, due to the structural action explained above. It can be realized.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of the joint with the tube attached, FIG. 2 is a perspective view of the joint body, FIG. 3 is a perspective view of the fastener, and FIG. 4 is a perspective view of the cap. In fig. l... Joint body 1a... Threaded part ib... Convex part lc... Latching part lcl... Groove ld... ... Outer peripheral wall 2 ... ... Fastener 2a ... ... Threaded part 2b ... ... Slit 2C ... ... Locking piece 2d ... ... Contact Part 3...Cap 3a...Edge 3b...Screw part Applicant

Claims (2)

[Claims] (1) Consists of a cylindrical joint body, a fastener that fits into the joint body, and a cap that screws onto the fastener. A threaded part is provided at the other end, a convex part is provided at the other end, and a hook part is provided between the threaded part and the convex part to prevent rotation of a fastener fitted to the outer periphery of the main body. The fastener has a threaded portion formed on its outer circumferential surface and a slit that expands in the axial direction when the fastener is fitted into the main body, and the cap has a threaded portion formed on its inner circumferential surface to be screwed into the threaded portion of the fastener. By forming a threaded part on the inside of the upper end and an edge on the inside of the upper end, and tightening the cap that screws into the fastener, the tube inserted into the outer periphery of the fitting body is connected to the edge of the cap and the upper end of the fastener. A joint characterized in that the tube is tightly fixed to a joint body attached to equipment, etc. by pressing the convex part of the tube. (2) The joint according to claim 1, wherein the fastener is provided with a locking piece, and the locking portion of the joint body is provided with a groove into which the locking piece fits.