PTFE multi-layer composite lining pipe fitting and manufacturing method thereof

Abstract

The invention relates to a PTFE multi-layer composite lining pipe fitting which comprises a metal pipe body, a composite lining is arranged on the inner wall of the metal pipe body, and the composite lining is of a three-layer structure and sequentially comprises a PFA layer, a stainless steel net and a PTFE layer from outside to inside. According to the TFE multi-layer composite lining pipe fitting, the stainless steel net is arranged as a reinforcing layer, so that the negative pressure resistance strength is improved, the pipe fitting can still keep a stable form in a negative pressure or vacuum environment, and the phenomena of bulging, shrinking, swelling and deformation of the PTFE layer are avoided.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of pipe processing, in particular to a PTFE multi-layer composite lining pipe fitting and a manufacturing method thereof. BACKGROUND

[0002] At present, in industrial production, especially in the field of chemical production, when encountering media under high temperature and strong corrosion conditions, metal pipes cannot be directly used or are difficult to be directly used, and metal pipes with polytetrafluoroethylene (PTFE) lining are often used, wherein polytetrafluoroethylene PTFE is known as "plastic king", has very high chemical stability, can resist corrosion of almost all strong acids, strong oxidizing agents, reducing agents and various organic solvents, and is also suitable for a relatively wide temperature and pressure range. The polytetrafluoroethylene (PTFE) lining is widely used in various industries as an effective corrosion protection measure for pipes, pipe fittings, containers and the like.

[0003] In actual application, the metal pipe with PTFE lining still has the problem of low negative pressure resistance, and cannot be used stably for a long time under negative pressure or vacuum environment, and the PTFE lining is prone to bulging and deflating, and expanding and deforming after long-term use. SUMMARY

[0004] Therefore, the purpose of the present application is to provide a PTFE multi-layer composite lining pipe fitting and a manufacturing method thereof, to improve the negative pressure resistance and avoid the phenomenon of PTFE layer bulging and deflating, and expanding and deforming.

[0005] The present application adopts the following scheme: a PTFE multi-layer composite lining pipe fitting, comprising a metal pipe body, a composite lining is arranged on the inner wall of the metal pipe body, and the composite lining has a three-layer structure, and the three layers are PFA layer, stainless steel mesh and PTFE layer from outside to inside.

[0006] Further, the PFA layer is fixed together with the inner wall of the metal pipe body, and the PTFE layer is bonded together with the PFA layer through the mesh holes of the stainless steel mesh.

[0007] Further, the PTFE layer is provided with a flange portion protruding from the pipe opening of the metal pipe body and fixed together with the end face of the pipe opening.

[0008] Further, the stainless steel mesh is made of 304 stainless steel.

[0009] Another technical solution of the present application: a manufacturing method of a PTFE multilayer composite corrugated pipe compensator, comprising the following steps: (1) sticking a PFA layer on the inner wall of a metal pipe body; (2) inserting a stainless steel mesh into the metal pipe body, the stainless steel mesh being tightly fitted with the metal pipe body to press the PFA layer against the inner wall of the metal pipe body; (3) welding the end of the stainless steel mesh with the pipe opening of the metal pipe body; (4) installing an isostatic pressure forming die into the metal pipe body, and filling PTFE powder into the powder forming cavity between the isostatic pressure forming die and the stainless steel mesh; (5) isostatic pressure forming the PTFE powder by using an isostatic pressure forming process to obtain a pipe fitting with a composite lining; (6) taking out the isostatic pressure forming die, and sintering the pipe fitting; (7) performing constant temperature stress relief treatment.

[0010] Further, in step (5), the medium for isostatic pressure forming is water, the pressure is 30 MPa, and the pressure holding time is 3 hours.

[0011] Further, in step (6), the sintering time is 23-25 hours, and the temperature is 370-380℃.

[0012] Further, in step (7), the temperature for constant temperature stress relief treatment is 180-250℃.

[0013] Compared with the prior art, the present application has the following beneficial effects: the TFE multilayer composite lining pipe fitting of the present application sets a stainless steel mesh as a reinforcing layer to improve the negative pressure strength, so that the pipe fitting can still maintain a stable form under negative pressure or vacuum environment, avoiding the phenomena of PTFE layer bulging, sucking, and expanding deformation To make the purpose, technical solutions and advantages of the present application clearer and more apparent, the following will further describe the present application in detail through specific examples and related drawings. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 is a sectional view of a straight pipe-shaped PTFE multilayer composite lining pipe fitting of an embodiment of the present application; Figure 2 is an exploded view of a straight pipe-shaped PTFE multilayer composite lining pipe fitting of an embodiment of the present application; Figure 3 is a sectional view of a special-shaped PTFE multilayer composite lining pipe fitting of an embodiment of the present application; DETAILED DESCRIPTION

[0015] It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs.

[0016] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0017] like Figures 1-2 As shown, a PTFE multi-layer composite lined pipe fitting is a straight pipe, comprising a metal pipe body 100, the inner wall of which is provided with a composite lining 200. The composite lining has a three-layer structure, consisting of a PFA layer 210, a stainless steel mesh 220, and a PTFE layer 230 from the outside in. This pipe fitting uses a stainless steel mesh as a reinforcing layer to improve its resistance to negative pressure, ensuring the fitting maintains a stable shape under negative pressure or vacuum conditions and preventing the PTFE layer from bulging, collapsing, or deforming. The PFA and PTFE layers work together to encase the stainless steel mesh in the middle, improving corrosion resistance. Combined with the PTFE layer, the composite lining structure allows the fitting to be used under higher positive and negative pressure, high temperature, and strong corrosion conditions. Even at temperatures below 180℃ and vacuum levels below 0.098MPa, sudden cooling or alternating heating and cooling will not cause the PTFE layer to detach, bulge, collapse, or deform, thus achieving steel-fluorine integration. This structure is suitable not only for straight pipes but also for irregularly shaped pipes, such as… Figure 3 As shown.

[0018] In this embodiment, the PFA layer is bonded to the inner wall of the metal pipe using epoxy adhesive. The PTFE layer permeates through the mesh of the stainless steel mesh and bonds to the PFA layer. The permeability of the stainless steel mesh acts as a permeation channel, allowing the PTFE layer to permeate through the mesh and bond to the PFA layer. Through the dual effects of physical interlocking and chemical bonding, the bonding strength between the layers is greatly improved, significantly enhancing the overall strength and service life of the pipe fitting.

[0019] In this embodiment, the PTFE layer has a flange 231 at the corresponding metal tube opening position, which extends out of the metal tube opening and is bonded to the end face of the opening.

[0020] In this embodiment, the stainless steel mesh is made of 304 stainless steel.

[0021] The application discloses a manufacturing method of a PTFE multilayer composite corrugated pipe compensator, and comprises the following steps: (1) sticking a PFA layer on the inner wall of a metal pipe body; (2) inserting a stainless steel mesh into the metal pipe body, and the stainless steel mesh is tightly matched with the metal pipe body to press the PFA layer on the inner wall of the metal pipe body; (3) welding the end of the stainless steel mesh with the pipe opening of the metal pipe body; (4) installing an isostatic pressure forming die into the metal pipe body, and filling PTFE powder into a powder forming cavity between the isostatic pressure forming die and the stainless steel mesh; (5) isostatic pressure forming the PTFE powder by adopting an isostatic pressure forming process, so as to obtain a pipe fitting with a composite lining; (6) taking out the isostatic pressure forming die, and sintering the pipe fitting; and (7) performing constant-temperature stress relief treatment.

[0022] After the composite lining is sintered for 23-25 hours (preferably 24 hours) at 370-380 DEG C, the bonding strength between the layers is greatly improved, so that the pipe fitting can be used under higher positive and negative pressure, high temperature and strong corrosion conditions, and is suitable for complex environments of sudden cooling and heating or cold and hot alternating operation. The isostatic pressure forming (30 MPa / 3h) makes the density of the PTFE powder reach more than 98%, which is increased by about 40% compared with the traditional molding process. The constant-temperature stress relief treatment (180-250 DEG C) reduces the residual stress, and effectively avoids the generation of microcracks in the using process.

[0023] In the embodiment, the medium for the isostatic pressure forming in step (5) is water, the pressure is 30 MPa, and the pressure maintaining time is 3 hours.

[0024] In the embodiment, in step (6), the sintering time is 23-25 hours, and the temperature is 370-380 DEG C.

[0025] In the embodiment, in step (7), the temperature for the constant-temperature stress relief treatment is 180-250 DEG C.

[0026] As shown in FIG. 1, the manufacturing process of the corrugated pipe compensator is as follows. Figure 3 As shown in FIG. 1, the manufacturing process of the corrugated pipe compensator is as follows.

[0027] Any technical solution disclosed in the application should be understood as follows: if the numerical range is disclosed, the disclosed numerical range is a preferred numerical range, and any person skilled in the art should understand that the preferred numerical range is only one of the many implementable numerical ranges with more obvious technical effects or representative numerical ranges. Since there are too many numerical ranges, it is impossible to enumerate all the numerical ranges, therefore, the application discloses part of the numerical ranges to illustrate the technical solutions of the application, and the above-mentioned enumerated numerical ranges should not be regarded as a limitation on the protection scope of the application.

[0028] If the present application discloses or involves mutually fixedly connected parts or structural members, unless otherwise stated, the fixed connection can be understood as: detachably fixedly connected (for example, connected using bolts or screws), and can also be understood as: non-detachable fixed connection (for example, riveting, welding), of course, the mutually fixed connection can also be replaced by an integral structure (for example, integrally formed by using a casting process) (obviously, an integral forming process cannot be used).

[0029] In addition, the terms used to represent the positional relationship or shape in any of the technical solutions disclosed in the present application include states or shapes similar, similar or close to them, unless otherwise stated.

[0030] Any component provided by the present application can be assembled from multiple individual components, or can be a single component manufactured by an integral forming process.

[0031] The above is only a preferred embodiment of the present application, and is not intended to limit the present application in other forms. Any person skilled in the art can modify or change the above disclosed technical content to equivalent embodiments. However, any simple modification, equivalent change and modification made on the basis of the technical essence of the present application without departing from the technical solution content of the present application still belongs to the protection scope of the present application technical solution.

Claims

1. A PTFE multilayer composite lined pipe fitting characterized by: The metal pipe body is internally provided with a composite lining, which is a three-layer structure and sequentially comprises a PFA layer, a stainless steel mesh and a PTFE layer from outside to inside.

2. The PTFE multilayer composite lined tubular article of claim 1, wherein: The PFA layer is fixed to the inner wall of the metal pipe body, and the PTFE layer is adhered to the PFA layer through the mesh holes of the stainless steel mesh.

3. The PTFE multilayer composite lined tubular article of claim 2, wherein: The PTFE layer is provided with a flange portion extending out of the pipe opening of the metal pipe body and adhered to the end face of the pipe opening.

4. The PTFE multilayer composite lined tubular article of claim 1, wherein: The stainless steel mesh is made of 304 stainless steel.

5. A method of manufacturing a PTFE multilayer composite corrugated pipe compensator, characterized by: The method comprises the following steps: (1) pasting the PFA layer on the inner wall of the metal pipe body; (2) inserting the stainless steel mesh into the metal pipe body, and tightly fitting the stainless steel mesh with the metal pipe body to press the PFA layer against the inner wall of the metal pipe body; (3) welding the end portion of the stainless steel mesh with the pipe opening of the metal pipe body; (4) installing an isostatic pressing forming die into the metal pipe body, and filling PTFE powder into the powder forming cavity between the isostatic pressing forming die and the stainless steel mesh; (5) isostatic pressing the PTFE powder by using an isostatic pressing forming process to obtain a pipe fitting with a composite lining; (6) taking out the isostatic pressing forming die, and sintering the pipe fitting; and (7) performing constant temperature stress relief treatment.

6. The production method according to claim 5, characterized by: In step (5), the medium for isostatic pressing is water, the pressure is 30 MPa, and the pressure maintaining time is 3 hours.

7. The production method according to claim 5, characterized by: In step (6), the sintering time is 23-25 hours, and the temperature is 370-380℃.

8. The production method according to claim 5, characterized by: In step (7), the temperature for constant temperature stress relief treatment is 180-250℃.

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