JPH1068480A - Teflon (r) pipe joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a Teflon (R) pipe joint in which a pipe will not fall off even if tensile load works on it, and besides, there is no drag in this Teflon pipe if a nut is turned round. SOLUTION: This Teflon (R) pipe joint is provided with a joint body 1 with a fluid passage in the axial direction, and a nut 2 being screwed in this joint body 1 and forcibly pressing a flare part 3a of a Teflon (R) pipe 3 to an end face of the joint body 1, respectively. In this case, a grooved sleeve 4 with a groove part facing on this flare part 3a, is installed in a peripheral wall at the flare part side of the Teflon (R) pipe 3, and a thrust washer 7 being small in a friction factor is installed on a nut side of this grooved sleeve 4, whereby this Teflon (R) pipe 3 will in no case fall off even if undue tensile load acts on it. In this connection, this pipe 3 will not be dragged at all if the nut 2 is turned round.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a Teflon pipe joint, and more particularly to a large diameter Teflon pipe joint.

[0002]

2. Description of the Related Art Conventionally, an electrically insulating Teflon pipe has been used for a pure water cooling pipe such as a DC rectifier, and a general-purpose double-ring type pipe as shown in FIG. Compression joints are used. This compression joint is composed of a joint body 21, a nut 22, and a compression ring 23 provided therebetween, and a tube 24 is inserted and connected inside thereof. The compression ring 2
Reference numeral 3 denotes a double ring including a front ring 23a and a back ring 23b.

[0003] Teflon pipe joints are often quenched from high temperatures in use, but the above-mentioned conventional compression joints are inferior in flexibility against expansion and shrinkage and are susceptible to thermal cycling.

In order to solve such a problem, the present applicant has previously proposed a joint for a Teflon pipe as shown in FIG. 6 in Japanese Utility Model Publication No. 3018028. This pipe joint has a joint body 11 having a fluid passage in the axial direction.
A disc spring 15 which is inserted into the outer peripheral wall of the Teflon tube 13 and has retainers 16 and 17 on both surfaces; and a flare portion 13a which is screwed with the joint body 11 and formed at the end of the Teflon tube 13 via the disc spring 15 And a nut 12 pressing the end face of the joint body 11 against the end face.

[0005]

In the latter Teflon pipe joint described in the prior art, the flare portion of the Teflon pipe and the joint body are formed through an elastic member such as a disc spring, as compared with the former double ring compression joint. It has excellent sealing performance against thermal cycling.

However, in the case of the Teflon pipe joint, when an excessive tensile load is applied to the Teflon pipe, a phenomenon that the Teflon pipe comes off may occur.
When the nut is tightened, a phenomenon that the Teflon tube rotates together may occur.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art. In the above-described joint for a Teflon pipe, even if a tensile load is applied, the Teflon pipe does not come off, and the nut is not removed. An object of the present invention is to provide a Teflon pipe joint in which the Teflon pipe does not rotate together even when turning.

[0008]

The present invention has solved the above-mentioned problems as follows. That is, in a joint for a Teflon pipe having a joint body having a fluid passage in the axial direction and a nut screwed with the joint body to press a flare portion of the Teflon tube against an end surface of the joint body, an outer periphery of the flare portion side of the Teflon tube is provided. A grooved sleeve having a groove facing the flare was provided on the wall, and a thrust washer having a small coefficient of friction was provided on the nut side of the grooved sleeve. As a result, the flare of the Teflon tube is pressed against the end face of the joint body by the grooved sleeve, so that even if an excessive tensile load is applied to the Teflon tube, the Teflon tube will not come off from the tube joint. Also,
By installing the thrust washer, the Teflon tube does not rotate even when the nut is turned.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A Teflon pipe joint according to the present invention has a Teflon having a joint body having a fluid passage in an axial direction, and a nut screwed with the joint body to press a flare portion of the Teflon pipe against an end face of the joint body. In the pipe joint, a grooved sleeve having a groove facing the flare portion is provided on an outer peripheral wall of the Teflon tube on the flare portion side, and a thrust washer having a small coefficient of friction is provided on a nut side of the grooved sleeve. And

The Teflon pipe joint preferably has a disc spring provided between the grooved sleeve and the thrust washer.

It is preferable that the flange of the nut presses the flare portion of the Teflon tube via a thrust washer.

Further, it is preferable that an annular groove into which the flare portion of the Teflon tube is inserted is formed on the end face of the joint body.

[0013]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view of an essential part in the axial direction showing the entire structure of a Teflon pipe joint.

In FIG. 1, reference numeral 1 denotes a joint main body, in which a fluid passage is formed in the axial direction. Male threads are respectively provided on both outer peripheral walls of the joint body 1, one end is screwed to a device (not shown) or the like, and the other end is screwed with a nut 2.

An annular groove 1a is formed concentrically on an end face of the joint body 1 on the nut side, and the bottom surface thereof corresponds to the angle (37 ° to 90 °) of the flare portion 3a of the Teflon tube 3 to be connected. It is shaped. Further, the annular groove 1 of the joint body 1
The inner wall part 1b of a extends in the axial direction longer than the outer wall part 1c. The inner peripheral wall of the flare portion 3a of the Teflon tube 3 is supported by the extended inner wall portion 1b.

A nut 2 to be screwed with the male screw of the joint body 1 is inserted into the outer peripheral wall of the Teflon tube 3, and a flange 2a is formed at an end of the nut 2 inward.

On the outer peripheral wall of the Teflon tube 3 on the flare side,
In order from the flare portion side, a grooved sleeve 4, a disc spring 5 as an elastic member, a retainer 6, and a thrust washer 7
Is provided, and is tightened by the flange 2a of the nut 2.

The surface of the grooved sleeve 4 on the flared portion side is subjected to groove cutting as shown in FIG. The grooving is preferably performed by round processing, but may be performed by spiral processing. Note that the hatched portion shown in FIG. 2B indicates a groove 4a having a chevron shape.

The thrust washer 7 is made of a material having a very small friction coefficient of 0.15 to 0.22, for example, manufactured by Norton (trade name: Metalloplast T). The thrust washer 7 is cut at one place as shown in FIG. 3 so that it can be easily removed when worn.

Next, the connection between the above-described Teflon pipe joint and the Teflon pipe will be described.

First, the nut 2, the thrust washer 7, the retainer 6, the disc spring 5, and the grooved sleeve 4 are sequentially fitted into the outer peripheral wall of the Teflon tube 3. Next, the tube end is heated and pressurized by a dedicated flaring machine to perform flaring at an angle in the range of 37 ° to 90 °. 90 ° is most preferred.

Next, the flare portion 3a of the Teflon tube 3 is inserted into the annular groove 1a provided on the end face of the joint body 1, and the nut 2 is tightened. Thereby, the collar 2 of the nut 2
a is a flare 3a of the Teflon tube 3 via a disc spring 5 or the like.
The part is pressed against the bottom of the annular groove 1a of the joint body 1. In this way, the connection between the joint body 1 and the Teflon tube 3 is made, and the internal fluid can be sealed. That is, when the nut 2 is tightened to the joint body 1 at a predetermined rotation speed or a predetermined torque, the disc spring 5 is compressed, and an appropriate sealing surface pressure is obtained.
It can absorb expansion and contraction due to thermal cycling.
At this time, since the inner peripheral wall of the flare portion 3a of the Teflon tube 3 is supported by the extended inner wall portion 1b of the joint main body 1, the center of the Teflon tube 3 and the joint main body 1 does not shift.

In the above-described embodiment, since the joint body 1 and the flared portion 3a of the Teflon tube 3 are fastened via an elastic member such as a disc spring 5, excellent sealing performance against high and low temperature heat cycles is achieved. However, if the thermal cycle does not significantly affect the sealing performance in use, as shown in FIG. 4, the grooved sleeve 4 is removed by removing the disc spring 5 and the retainer 6 from the Teflon pipe joint described above. And the thrust washer 7 alone, and can be an inexpensive Teflon pipe joint.

[0025]

Since the present invention is configured as described above, the following effects can be obtained. That is, since the flare portion of the Teflon tube is pressed by the grooved sleeve against the annular groove of the joint body, even if an excessive tensile load acts on the Teflon tube, the flare portion does not fall out of the tube joint. Further, since the thrust washer having a small friction coefficient is provided on the nut side of the grooved sleeve, the Teflon tube does not rotate together even when the nut is turned.

[Brief description of the drawings]

FIG. 1 is a sectional view of a principal part in the axial direction showing a Teflon pipe joint according to an embodiment of the present invention.

FIG. 2 is a view showing a grooved sleeve, wherein FIG. 2 (a) is a front view and FIG. 2 (b) is a side view.

3A and 3B are diagrams showing a thrust washer, wherein FIG. 3A is a front view and FIG. 3B is a side view.

FIG. 4 is a sectional view of a main part in the axial direction showing a Teflon pipe joint according to another embodiment of the present invention.

FIG. 5 is an axial sectional view showing a conventional double-ring type compression joint.

FIG. 6 is a sectional view of a principal part in the axial direction showing a conventional Teflon pipe joint.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Joint main body 1a Annular groove 1b Inner wall 1c Outer wall 2 Nut 2a Flange 3 Teflon tube 3a Flare 4 Slotted sleeve 4a Groove 5 Disc spring (elastic member) 6 Retainer 7 Thrust washer

Claims (4)

[Claims] A joint body (1) having a fluid passage in the axial direction, and a Teflon tube (3) screwed with the joint body (1).
In a Teflon pipe joint having a nut (2) for pressing the flare portion (3a) of the joint body (1) against the end face of the joint body (1), the outer wall of the Teflon tube (3) on the flare portion side has a surface facing the flare portion (3a). A grooved sleeve (4) having a groove (4a), and a thrust washer (7) having a small coefficient of friction provided on the nut side of the grooved sleeve (4). 2. The joint for a Teflon pipe according to claim 1, wherein a disc spring (5) is provided between the grooved sleeve (4) and a thrust washer (7). 3. A flange (2a) of a nut (2) is connected to a flare portion (3) of a Teflon tube (3) through a thrust washer (7).
3. The Teflon pipe joint according to claim 1, wherein a) is pressed. 4. An annular groove (1a) into which a flare portion (3a) of a Teflon tube (3) is inserted into an end face of a joint body (1).
4. The joint for a Teflon pipe according to claim 1, wherein the joint is formed.