Die for manufacturing polytetrafluoroethylene lining of reducing pipe

Abstract

The utility model discloses a mould for manufacturing a Teflon lining of a reducing pipe, which comprises an outer mould, an inner mould, a cover plate and a positioning plate, the outer mould and the inner mould are of special-shaped structures and are matched with each other in appearance, the inner mould is arranged in the outer mould, the cover plate and the positioning plate are respectively arranged at two ends of the outer mould and the inner mould, and the cover plate and the positioning plate are matched with the outer mould and the inner mould. And the outer mold, the inner mold, the cover plate and the positioning plate are encircled to form a mold cavity. According to the specification of the reducing pipe, the polytetrafluoroethylene lining piece can be prefabricated by using the mould, the polytetrafluoroethylene lining piece is sintered, demoulded and then lined into the reducing pipe steel piece, and the sealing surface is flanged to compound the polytetrafluoroethylene lining piece and the reducing pipe steel piece together, so that the problems that the polytetrafluoroethylene is gradually delaminated from the steel piece due to the shrinkage of the polytetrafluoroethylene in the sintering process in the compression molding process, and the service life of the polytetrafluoroethylene lining piece is prolonged can be solved. The sealing surface is shrunk or the lining piece is cracked.

Description

Technical Field

[0001] This utility model relates to the field of steel-lined PTFE reducers, and mainly to a mold for making PTFE liners for reducers. Background Technology

[0002] PTFE-lined steel pipes are a common accessory in corrosion-resistant equipment used in tower sections, reactors, and other fields. PTFE-lined steel pipes are composite pipe fittings made of a metal outer shell (usually carbon steel or stainless steel) lined with polytetrafluoroethylene (PTFE, commonly known as tetrafluoroethylene), combining the mechanical strength of metal with the chemical inertness of PTFE.

[0003] Steel-lined PTFE reducers are a type of steel-lined PTFE pipe. They are generally manufactured using a molding process, where the sealing surface and the lining are formed in one piece. During sintering, filler material is used to support the inner wall, making the lining and the steel part a single unit.

[0004] However, the inventors of this application have discovered that in actual use, the PTFE (liner) itself shrinks during the sintering process of the compression molding process, which causes it to gradually delaminate from the steel parts, resulting in shrinkage of the sealing surface or cracking of the liner, which can lead to leakage of the medium or corrosion of the steel parts, thereby causing safety hazards. Utility Model Content

[0005] This invention aims to solve some problems existing in the prior art. Therefore, the purpose of this invention is to provide a mold for manufacturing PTFE liners for reducers, eliminating the effects of sealing surface shrinkage or lining cracking, and ensuring safe use.

[0006] To achieve the above objectives, this utility model employs the following technical solution:

[0007] A mold for making PTFE liners for reducing pipes includes an outer mold, an inner mold, a cover plate, and a positioning plate. The outer mold and the inner mold are irregularly shaped and their shapes are compatible. The inner mold is disposed inside the outer mold. The cover plate and the positioning plate are respectively disposed at both ends of the outer mold and the inner mold. The outer mold, the inner mold, the cover plate, and the positioning plate together form a mold cavity.

[0008] Furthermore, based on the above scheme, a spacer is provided on the inner mold, the spacer is fitted with the inner mold, and the two ends of the spacer are provided with first flanges.

[0009] Furthermore, based on the above solution, the outer mold is provided with second flanges at both ends, the first flange portion at one end of the outer mold is clamped between the cover plate and the second flange, and the first flange portion at the other end of the outer mold is clamped between the positioning plate and the second flange.

[0010] Furthermore, based on the above solution, both the cover plate and the positioning plate are provided with sealing grooves, and sealing strips are installed in the sealing grooves.

[0011] Furthermore, based on the above scheme, a positioning ring is provided on the positioning plate, and the outer diameter of the positioning ring is smaller than the inner diameter at the smallest point of the inner mold.

[0012] Furthermore, the outer wall of the positioning ring is provided with a beveled surface.

[0013] Furthermore, based on the above solution, the cover plate and the second flange, and the positioning plate and the second flange are provided with through holes at corresponding positions, and fasteners are installed in the through holes.

[0014] Furthermore, based on the above solution, both the cover plate and the positioning plate have through holes in the middle.

[0015] Compared with the prior art, the beneficial effects of this utility model are:

[0016] According to the specifications of the reducer, the PTFE liner can be prefabricated using the mold of this utility model. After sintering, it is demolded and then inserted into the steel part of the reducer. The sealing surface is turned up so that the two (PTFE liner and reducer steel part) are combined together. This can eliminate the problems of PTFE shrinkage and gradual delamination from the steel part, shrinkage of the sealing surface or cracking of the liner during the sintering process of the molding process.

[0017] The features and advantages of this utility model will be described in detail through embodiments in conjunction with the accompanying drawings. Attached Figure Description

[0018] Figure 1 A cross-sectional view of a mold used to manufacture PTFE liners for reducers;

[0019] Figure 2 for Figure 1 Enlarged view of point A in the image;

[0020] Figure 3 for Figure 1 Enlarged view of point B in the image;

[0021] Figure 4 This is a cross-sectional view of a liner and a matching steel part manufactured using the mold of this utility model.

[0022] Figure label:

[0023] 1. Outer mold, 2. Inner mold, 3. Cover plate, 4. Positioning plate, 5. Mold cavity, 6. Spacer, 7. First flange, 8. Second flange, 9. Sealing groove, 10. Sealing strip, 11. Positioning ring, 12. Beveled surface, 13. Fastener, 14. Steel part, 15. Liner. Detailed Implementation

[0024] To make the technical means, creative features, objectives and effects of this utility model easier to understand, the present utility model will be further described below in conjunction with specific embodiments.

[0025] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numerals in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses consistent with some aspects of this application as detailed in the appended claims.

[0026] The terminology used in this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. Unless otherwise defined, the technical or scientific terms used in this application should be understood in their ordinary sense by one of ordinary skill in the art to which this utility model pertains. The words “a” or “one” and similar terms used in this application specification and claims do not indicate a limitation of quantity, but rather indicate the presence of at least one. “A plurality” includes two, equivalent to at least two. The words “comprising” or “including” and similar terms mean that the element or object preceding “comprising” or “including” covers the element or object listed following “comprising” or “including” and its equivalents, and does not exclude other elements or objects. The words “connected” or “linked” and similar terms are not limited to physical or mechanical connections and can include electrical connections, whether direct or indirect. The singular forms “a,” “the,” and “the” used in this application specification and appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any or all possible combinations of one or more associated listed items.

[0027] Please refer to the following for details. Figure 1-3 A mold for making PTFE linings for reducing pipes includes an outer mold 1, an inner mold 2, a cover plate 3, and a positioning plate 4. The outer mold 1 and the inner mold 2 are irregularly shaped and their shapes are compatible. The cover plate 3 and the positioning plate 4 are both provided with through holes in the middle. The inner mold 2 is set inside the outer mold 1. The cover plate 3 and the positioning plate 4 are respectively set at both ends of the outer mold 1 and the inner mold 2, and the cover plate 3 and the positioning plate 4 are respectively fixedly connected to the outer mold 1. The outer mold 1, the inner mold 2, the cover plate 3, and the positioning plate 4 together form a mold cavity 5.

[0028] Based on the above technical means: PTFE material can be filled into the mold cavity 5, and then sintered. After sintering, the product is cooled to room temperature. After the PTFE liner 15 has completely cooled and shrunk, the mold is removed. Finally, the sealing surface of each end face of the PTFE liner 15 is turned over. That is, the liner 15 is sintered first, then placed into the special-shaped steel part 14, and finally the sealing surface of each end face of the liner 15 is turned over. This can eliminate the problems of PTFE shrinkage and gradual delamination from the steel part 14, sealing surface shrinkage, or liner 15 cracking during the sintering process of the compression molding process.

[0029] Specifically, a spacer 6 is fitted on the inner mold 2. The spacer 6 is made of rubber and fits into the inner mold 2. The spacer 6 has a first flange 7 at both ends. The design of the spacer 6 prevents the PTFE material from sticking to the inner mold 2 and makes it easy to detach from the inner mold 2.

[0030] Specifically, the outer mold 1 has second flanges 8 at both ends. The first flange 7 at one end of the outer mold 1 is clamped between the cover plate 3 and the second flange 8, and the first flange 7 at the other end of the outer mold 1 is clamped between the positioning plate 4 and the second flange 8. The cover plate 3 and the second flange 8, and the positioning plate 4 and the second flange 8 are provided with through holes at corresponding positions. Fasteners 13 are installed in the through holes. That is, the cover plate 3 and the positioning plate 4 are fixed to the outer mold 1 by the fasteners 13, and the inner mold 2 is snapped onto the cover plate 3 and the positioning plate 4.

[0031] Specifically, both the cover plate 3 and the positioning plate 4 are provided with sealing grooves 9, and sealing strips 10 are installed in the sealing grooves 9. The sealing grooves 9 are located on one end face close to the first flange 7. The sealing grooves 9 are semi-circular grooves. The end face of the sealing strip 10 contacts the first flange 7 of the spacer 6 to play a sealing role.

[0032] Specifically, a positioning ring 11 is provided on the positioning plate 4. The outer diameter of the positioning ring 11 is smaller than the inner diameter of the smallest part of the inner mold 2. The outer diameter of the positioning ring 11 is 0.2mm smaller than the inner diameter of the smallest part of the inner mold 2. That is, the lower end of the inner mold 2 is inserted into the positioning ring 11, and the positioning and limiting are performed by the positioning ring 11. Since the outer diameter of the positioning ring 11 is smaller than the inner diameter of the smallest part of the inner mold 2, the inner mold 2 can be fixed by friction.

[0033] Specifically, the outer wall of the positioning ring 11 is provided with a beveled surface 12, and the design of the beveled surface 12 facilitates the insertion of the inner mold 2 into the positioning ring 11.

[0034] This utility model relates to a mold for manufacturing PTFE liners for reducers, and its working principle is explained in conjunction with the accompanying drawings:

[0035] First, connect the outer mold 1 and the positioning plate 4 using fasteners 13. Place the spacer 6 over the inner mold 2 and install both onto the positioning ring 11 of the positioning plate 4. Then, fill the mold cavity 5 with PTFE material and compact it using a vibratory mixer. Next, install the cover plate 3 onto the outer mold 1 using fasteners 13 and place it in an isobaric reactor for pressure testing. After completion, remove the cover plate 3, positioning plate 4, spacer 6, and inner mold 2. Place the outer mold 1 and the PTFE material together into a PTFE sintering furnace for sintering, forming a liner 15 without flanges. Finally, after placing the reducing steel part 14, flange the sealing surface of the liner 15 to form a shape like... Figure 4 The steel-lined PTFE reducer shown is shown.

[0036] It should be noted that: the inner diameters at both ends of the outer mold 1 should take into account the circumferential shrinkage rate after PTFE sintering, and the PTFE flange length and reducer height should take into account the longitudinal shrinkage rate after sintering. The circumferential shrinkage rate is 3% and the longitudinal shrinkage rate is 4%. Specific situations need to be analyzed specifically. The outer diameters at both ends of the mold core are calculated based on the wall thickness of the PTFE liner 15. The outer diameter of the mold core is the inner diameter of the outer mold 1 minus 3 times the thickness of the liner 15.

[0037] The foregoing has shown and described the basic principles, main features, and advantages of this utility model. Those skilled in the art should understand that this utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of this utility model. Various changes and modifications can be made to this utility model without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claims. The scope of protection of this utility model is defined by the appended claims and their equivalents.

Claims

1. A mold for manufacturing PTFE liners for reducers, characterized in that, It includes an outer mold, an inner mold, a cover plate, and a positioning plate. The outer mold and the inner mold are irregularly shaped and their shapes are compatible. The inner mold is set inside the outer mold. The cover plate and the positioning plate are respectively set at both ends of the outer mold and the inner mold. The outer mold, the inner mold, the cover plate, and the positioning plate together form a mold cavity.

2. The mold for manufacturing PTFE linings for reducers according to claim 1, characterized in that, The inner mold is fitted with a spacer sleeve, which fits into the inner mold, and the spacer sleeve has a first flange at both ends.

3. The mold for manufacturing PTFE liners for reducers according to claim 2, characterized in that, The outer mold has second flanges at both ends. The first flange at one end of the outer mold is clamped between the cover plate and the second flange, and the first flange at the other end of the outer mold is clamped between the positioning plate and the second flange.

4. The mold for manufacturing PTFE liners for reducers according to claim 1 or 3, characterized in that, Both the cover plate and the positioning plate are provided with sealing grooves, and sealing strips are installed in the sealing grooves.

5. The mold for manufacturing PTFE linings for reducers according to claim 1, characterized in that, The positioning plate is provided with a positioning ring, the outer diameter of which is smaller than the inner diameter at the smallest point of the inner mold.

6. The mold for manufacturing PTFE liners for reducers according to claim 5, characterized in that, The outer wall of the positioning ring is provided with a beveled surface.

7. The mold for manufacturing PTFE liners for reducers according to claim 4, characterized in that, The cover plate and the second flange, and the positioning plate and the second flange are provided with through holes at corresponding positions, and fasteners are installed in the through holes.

8. The mold for manufacturing PTFE liners for reducers according to claim 1, characterized in that, Both the cover plate and the positioning plate have through holes in the middle.

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