CN211371519U

CN211371519U - Connecting structure of metal pipe fitting and fluorine resin lining pipe fitting

Info

Publication number: CN211371519U
Application number: CN201922316961.4U
Authority: CN
Inventors: 杨文光; 陈佩民; 夏炎; 王孝刚; 徐辉; 汪海飞; 刘向阳; 张敏华
Original assignee: Nanjing Comptech Composites Corp
Current assignee: Nanjing Comptech Composites Corp
Priority date: 2019-12-21
Filing date: 2019-12-21
Publication date: 2020-08-28
Anticipated expiration: 2029-12-21

Abstract

The utility model aims at overcoming the defects existing in the connection structure of the metal pipe fitting and the fluororesin lining pipe fitting in the prior art, providing the connection structure of the metal pipe fitting and the fluororesin lining pipe fitting, wherein the interference fit of the metal pipe fitting and the fluororesin lining pipe fitting is linear fit, and the connection structure has the advantages of simple structure, small assembly difficulty, reliable axial and radial limiting effects of the metal pipe fitting on the fluororesin lining pipe fitting so as to prevent the unfavorable conditions of radial displacement and axial movement of the fluororesin lining pipe fitting in the metal pipe fitting; the metal pipe fitting is lined with a fluororesin lining pipe fitting made of fluororesin materials, a pair of metal structural members are hermetically connected with adjacent end faces of the interfaces of a left pipe member and a right pipe member of the metal pipe fitting in a sealing manner, annular small bosses are convexly arranged in outer openings of the left pipe member and the right pipe member, and the fluororesin lining pipe fitting is in interference fit with the left pipe member and the right pipe member respectively through the annular small bosses.

Description

Connecting structure of metal pipe fitting and fluorine resin lining pipe fitting

Technical Field

The utility model provides a connection structure of metal pipe fitting and fluororesin lining pipe fitting.

Background

In some pipeline transportation that has corrosive fluid, conveying line 1 includes metal pipe fitting 2 and the lining pipe fitting of lining in metal pipe fitting 2, and when metal pipe fitting 2 docks, anticorrosive and sealing process need carry out, still need set firmly a pair of metallic structure 4 and connect a pair of metallic structure 4 through the welding solid at the

pipe fittings

201, 202 kneck about metal pipe fitting 2.

Fluororesin pipelines are a more commonly used lining pipe material because of excellent corrosion resistance and high temperature resistance (can resist the action of high welding temperature) and low friction factor.

Most of these corrosive fluids are operated in a low temperature or high and low temperature reciprocating environment, and the general metal pipe member 2 connection structure is assembled at a normal temperature. Thus, the fluororesin-lined pipe 3 is required to meet the technical requirements of easy assembly in a normal temperature environment, and no falling or excessive deformation in operation in low-temperature and high-low temperature environments, so as to reduce the undesirable phenomena of leakage, operation rattling and the like.

However, since the fluororesin inherently has characteristics such as easy creep, low strength, low heat distortion temperature, and a linear thermal expansion coefficient higher than that of a conventional metal, it is necessary to overcome the above-mentioned disadvantages of the fluororesin-lined pipe 3 made of a fluororesin material when the metal pipe 2 is butted.

In order to solve the above problems, the technical solutions adopted in the prior art are mostly:

1. referring to FIG. 1:

the left fluororesin lining pipe fitting 3 is embedded in the left pipe member 201 of the metal pipe fitting 2 through the interference fit 6, and the right end of the fluororesin lining pipe fitting 3 is limited by the end surface limiting step 5 arranged in the outer opening of the right end of the right pipe member 202 of the metal pipe fitting 2 in a protruding manner.

The disadvantages are as follows: the left side face contact interference fit part 6 shrinks at low temperature to generate looseness, and meanwhile, the fluororesin lining pipe fitting 3 also shrinks in the axial direction, so that the limiting effect of the right side end face limiting step 5 is reduced.

2. Referring to FIG. 2:

the fluororesin lining pipe fitting 3 is embedded in the metal pipe fitting 2, and the left end and the right end of the fluororesin lining pipe fitting 3 are limited by end surface limiting steps 5 which are respectively convexly arranged in the outer openings of the left end, the right end and the left end of the left pipe member 201 and the right end of the 202 of the metal pipe fitting 2.

The disadvantages are as follows: after the left end face and the right end face of the fluororesin lining pipe fitting 3 are limited, the limiting effect of the end faces at the two ends is limited due to the axial shrinkage of the fluororesin lining pipe fitting 3 at low temperature. At the same time, at high temperature, the fluororesin-lined pipe 3 is subjected to a large axial pressure applied by the metal pipe 2 due to the axial expansion of the fluororesin-lined pipe 3.

3. Referring to FIG. 3:

both left and right ends of the fluorine resin lined pipe 3 are fitted into left and

right pipe members

201, 202 of the metal pipe 2 by interference fit 6.

The disadvantages are as follows: with the interference fit, creep may occur in the long-term fluororesin-lined pipe 3, and at the same time, in the contact area of the interference fit surface, the fluororesin-lined pipe 3 may still shrink during cooling and may be separated from the metal pipe 2. And the important defect of this technique is that because the interference fit area is bigger, the installation process is more complicated, and the technical requirement is higher.

Disclosure of Invention

The utility model aims at overcoming the weak point that exists among the prior art in the connection structure of metal pipe fitting and fluororesin lining pipe fitting, providing a connection structure of metal pipe fitting and fluororesin lining pipe fitting, the interference fit of metal pipe fitting and fluororesin lining pipe fitting is linear fit, has simple structure, the assembly degree of difficulty is little, metal pipe fitting is reliable in order to prevent the unfavorable condition of fluororesin lining pipe fitting radial displacement and axial float in metal pipe fitting to fluororesin lining pipe fitting axial and radial limiting displacement.

The utility model aims at realizing through the following technical scheme:

the utility model provides a connection structure of metal pipe fitting and fluororesin lining pipe fitting, includes the metal pipe fitting, and the lining is established the fluororesin lining pipe fitting made by fluororesin material in the metal pipe fitting, and the adjacent terminal surface sealing connection of sealing connection is a pair of metallic structure at left and right sides pipe member kneck of metal pipe fitting, and the outer mouthful of pipe member is protruding to establish annular little boss about, and fluororesin lining pipe fitting passes through annular little boss respectively with control pipe member interference fit.

The utility model has the advantages that:

when the connecting structure of the metal pipe fitting and the fluorine resin lining pipe fitting is used:

1. the surface contact interference fit of the fluorine resin lined pipe fitting and the metal pipe fitting adopted in the prior art is changed during assembly into the contact interference fit of the fluorine resin lined pipe fitting and the small cambered surface of the metal pipe fitting in the technology, and the small cambered surface has smaller size relative to the wall thickness and the pipe diameter of the fluorine resin lined pipe fitting, so the contact interference fit of the fluorine resin lined pipe fitting and the small cambered surface of the metal pipe fitting can approach to the linear contact interference fit of the fluorine resin lined pipe fitting and the metal pipe fitting, and the assembly difficulty is small.

2. The physical property of the fluororesin lining pipe fitting is fully utilized, the contact interference fit position of the fluororesin lining pipe fitting and the small cambered surface of the annular small boss generates a depression, and the outer diameter of the fluororesin lining pipe fitting outside the position at low temperature can also be larger than the inner diameter of the metal pipe fitting at the contact interference fit position (the closing-in position) of the small cambered surface, so that the radial limiting effect is realized.

3. Even if the fluororesin lining pipe fitting shrinks at the small cambered surface contact interference fit position under creep deformation and/or low temperature, the limit action at the two side closing mouths limits the movement of the fluororesin lining pipe fitting and plays a role in axial limit because the fluororesin lining pipe fitting is locally positioned in the area of linear contact interference fit.

The connection structure of the metal pipe fitting and the fluororesin lining pipe fitting has the advantages that the interference fit of the metal pipe fitting and the fluororesin lining pipe fitting is linear fit, the structure is simple, the assembly difficulty is small, the axial and radial limiting effects of the metal pipe fitting on the fluororesin lining pipe fitting are reliable, and the adverse conditions of radial displacement and axial movement of the fluororesin lining pipe fitting in the metal pipe fitting are prevented.

According to the connecting structure of the metal pipe fitting and the fluororesin lining pipe fitting, the cross section of the small annular boss is semicircular, and the semicircular chord coincides with the generatrix of the inner hole of the left pipe member and the right pipe member, so that the component force of the interaction force between the small annular boss and the concave part of the fluororesin lining pipe fitting in the axial direction tends to be the largest, and the circumferential and axial limiting of the metal pipe fitting on the fluororesin lining pipe fitting is facilitated.

In the connecting structure of the metal pipe fitting and the fluororesin lining pipe fitting, the fluororesin lining pipe fitting can be a PTFE suspension plunger extrusion pipe, a PTFE dispersion extrusion pipe, a PFA extrusion pipe, an FEP extrusion pipe, a PVDF extrusion pipe and an ETFE extrusion pipe, and the connecting structure has better suitability.

Drawings

FIG. 1 is a schematic diagram of prior art solution 1;

FIG. 2 is a schematic diagram of technical scheme 2 in the prior art;

FIG. 3 is a schematic diagram of prior art solution 3;

FIG. 4 is a schematic view showing a connection structure of a metal pipe and a fluorine resin-lined pipe;

fig. 5 is an enlarged view at I of fig. 4.

Detailed Description

The present invention will be further explained with reference to the accompanying drawings:

referring to fig. 4 and 5, the connection structure of the metal pipe and the fluororesin-lined pipe comprises a metal pipe 2 composed of left and

right pipe members

201 and 202 which are linearly arranged, a fluororesin-lined pipe 3 made of fluororesin material and lined in the metal pipe 2, a pair of metal structural members 4 which are hermetically connected at the adjacent end faces of the joints of the left and

right pipe members

201 and 202 of the metal pipe 2, annular small bosses 7 which are convexly arranged in the outer openings of the left and

right pipe members

201 and 202, and the fluororesin-lined pipe 3 is in interference fit with the left and

right pipe members

201 and 202 respectively through the annular small bosses 7.

In the connecting structure of the metal pipe fitting and the fluorine resin lined pipe fitting, the cross section of the small annular boss 7 is a semi-circle 8, and the chord 801 of the semi-circle 8 is superposed with the generatrix 203 of the inner holes of the left pipe member and the right pipe member, so that the component force of the interaction force between the small annular boss 7 and the sunken part of the fluorine resin lined pipe fitting 3 in the axial direction tends to be maximum, and the circumferential and axial limiting of the metal pipe fitting 2 on the fluorine resin lined pipe fitting 3 is facilitated. The radius r of the semicircular section 8 of the small annular boss 7 is mainly determined according to the wall thickness h of the fluororesin-lined pipe 3, and the empirical data indicates that r is (h/10) - (h/5), in the case, r is (h/8).

In the above-mentioned connection structure of the metal pipe and the fluorine resin-lined pipe, the fluorine resin-lined pipe 3 may include, but is not limited to, a PTFE suspended plunger extruded pipe, a PTFE dispersed extruded pipe, a PFA extruded pipe, an FEP extruded pipe, a PVDF extruded pipe, and an ETFE extruded pipe, and has better suitability.

In this example, the fluororesin-lined tube is a PTFE floating plunger extrusion tube.

Next, the use of the above-described connection structure between the metal pipe and the fluororesin-lined pipe will be described by taking the fluororesin-lined pipe as an example of the PTFE floating plunger extruded pipe.

The extruded pipe of the PTFE suspension plunger has a pipe diameter of 12mm, a wall thickness of 1mm, and a linear expansion coefficient (-40-23 deg.C, 1.4 x 10)^- ⁴mm/mm·℃），r＝（h／8）＝0.125mm。

The utility model has the advantages that:

the connecting structure of the metal pipe fitting and the fluororesin lining pipe fitting has the advantages that the interference fit of the metal pipe fitting and the fluororesin lining pipe fitting is linear fit, the structure is simple, the assembly difficulty is small, the axial and radial limiting effects of the metal pipe fitting on the fluororesin lining pipe fitting are reliable, so that the adverse conditions of radial displacement and axial movement of the fluororesin lining pipe fitting in the metal pipe fitting are prevented, and the connecting structure has obvious guiding significance for the connecting production practice of the metal pipe fitting and the fluororesin lining pipe fitting.

Claims

1. A connecting structure of a metal pipe fitting and a fluororesin lining pipe fitting comprises the metal pipe fitting, wherein the fluororesin lining pipe fitting made of fluororesin materials is lined in the metal pipe fitting, and a pair of metal structural members are connected to adjacent end faces of left and right pipe member connectors of the metal pipe fitting in a sealing manner.

2. A joint structure of a metal pipe and a fluorine resin lined pipe as recited in claim 1, wherein the cross section of the small annular boss is semicircular, and a chord of the semicircle coincides with a generatrix of the inner hole of the left and right pipe members.

3. The structure of claim 1, wherein the fluororesin-lined pipe member is selected from the group consisting of a PTFE floating plunger extruded pipe, a PTFE dispersion extruded pipe, a PFA extruded pipe, an FEP extruded pipe, a PVDF extruded pipe, and an ETFE extruded pipe.