WO2008043237A1

WO2008043237A1 - Metal pipe with lining and its manufacturing method

Info

Publication number: WO2008043237A1
Application number: PCT/CN2007/002608
Authority: WO
Inventors: Ruquan Mo
Original assignee: Guangdong Successful Man Pipe Co., Ltd.
Priority date: 2006-09-08
Filing date: 2007-08-31
Publication date: 2008-04-17
Also published as: NZ576166A; GB0906145D0; CN200946722Y; RU2009113170A; GB2455675B; GB2455675A; AU2007306853A1

Abstract

A metal pipe with a plastic lining includes a metal pipe (1), the inner wall of said pipe (1) lined with a first protecting layer (2) and the outer wall covered by a second protecting layer (3). Said first protecting layer (2) is made from polyethylene or polypropylene material, and the second protecting layer (3) is made from polyvinyl chloride film. Accordingly, a method for making the pipe includes the following steps: a. preparing the metal blank pipe used for the metal pipe (1) and the plastic blank pipe used for the first protecting layer (2); b. putting the plastic blank pipe into the metal blank pipe and stretching forcibly the metalblank pipe to reduce the radial dimension to make it excessively fit with the plastic pipe blank; c. conducting repeated ageing to the stretched metal blank pipe and plastic blank pipe at given temperature to eliminate the processing stress and the remained inner stress of the material.

Description

Lining plastic metal pipe and manufacturing method thereof

The present invention relates to a plastic-lined metal pipe and a method of manufacturing the same, and the metal pipe particularly refers to a metal pipe suitable for use in a water purification system, a building water supply system, and a fluid transportation in food, medicine, brewing, and the like. technical background

Fluid transport in water purification systems, building water supply systems, and food, pharmaceutical, brewing, and other industries is usually pipelined. In the traditional technology, due to the lack of corresponding protective measures, these pipelines will appear due to oxidation during use. Corrosion, therefore, the life of such pipes is limited and the quality of the fluid being transported is difficult to guarantee.

In the case of adapting to low quality requirements, there are specific application examples of using plastic pipes for fluid transportation in the conventional technology. It is obvious that the conveying quality of such pipes is difficult to guarantee, mainly due to insufficient strength of the materials.

There is a prior art in the industry in which steel pipes and plastic pipes are combined in various ways, and it is often necessary to combine the adhesives to achieve the purpose of rust prevention by the protection of the plastic pipes inside the steel pipes. However, in practical applications, due to the deficiencies of the technology itself, the plastic pipes of such conveying pipes are generally easy to fall off or loose, and the service life is not long. Therefore, it is actually not effective for effective rust prevention, and sometimes even counterproductive. Summary of the invention

SUMMARY OF THE INVENTION The object of the present invention is to overcome the above-mentioned deficiencies and to provide a 4-plastic metal pipe and a manufacturing method thereof, which can effectively prevent a rusted metal pipe from contaminating a transported fluid during use.

The object of the present invention is achieved by the following technical solutions:

The metal-lined metal pipe of the present invention is used for fluid transmission, including a metal pipe body, the metal pipe body

(1) The inner wall is tightly lined with a first protective layer (2), and the outer wall of the metal tube is covered with a second protective layer (3).

The first protective layer (2) is made of a polyethylene or polypropylene material and is required to meet hygienic standards of non-toxic food grade. Confirmation The second protective layer (3) is a polyvinyl chloride film.

The metal pipe body is made of an aluminum alloy pipe and is a seamless pipe body.

The method for manufacturing a metal-lined metal pipe of the present invention comprises the following steps:

a metal embryo tube as a metal tube body and a plastic endoderm tube as the first protective layer; b. placing the plastic endoderm tube in the metal embryo tube and forcibly stretching the metal tube Reducing its radial dimension to form an interference fit with the plastic endoderm;

c Repeated aging treatment of the metal composite tube and the plastic endoderm after stretching and compounding to remove material processing stress and residual internal stress.

The specific temperature at the time of the aging treatment in step c is -20 to 100 degrees Celsius.

The outer diameter of the plastic endoderm in step a is 2 to 3 mm smaller than the inner diameter of the metal pipe. Preferably, the metal embryo material is made of aluminum alloy, and the material of the plastic inner tube is made of polyethylene or polypropylene.

In addition, the method further includes the step d: coating a plastic film as a second protective layer on the outer wall of the metal blank tube, made of polyvinyl chloride, and coated on the metal blank tube in the same process as steps a, b, and c. Outer wall.

Compared with the prior art, the invention has the following advantages: the plastic inner tube of the inner layer is organically combined by lining the first protective layer of the non-toxic food grade on the inner wall of the metal pipe, thereby organically combining the advantages of the metal and the plastic. The pipe is clean and hygienic, no scaling, no rust, and the metal pipe body can be separated from the fluid to prevent the rust of the metal pipe body from polluting the transported fluid; at the same time, the metal pipe body makes the pipe material have higher The mechanical strength, while the second protective layer coated on the outer surface of the pipe, allows the pipe to be better protected during application and construction. DRAWINGS

Figure 1 is a schematic longitudinal cross-sectional view of a metal-lined metal pipe of the present invention;

2 is a schematic cross-sectional view of a metal-lined metal pipe of the present invention. detailed description

The present invention will be further described below in conjunction with the accompanying drawings and embodiments:

Referring to Figures 1 and 2, the plastic-lined metal pipe of the present invention has a three-layer structure, specifically including a metal pipe body 1, a first protective layer 2, and a second protective layer 3.

The metal pipe body 1 mainly serves to strengthen the mechanical strength of the pipe material, and various fittings can be used. Made of alloys for strength requirements in body applications. Commonly used materials such as steel, aluminum, iron, etc., are available. In the present embodiment, the aluminum alloy material is used, and the aluminum alloy material is light and durable, and is not easily rusted, so it is more practical than the steel material.

The first protective layer 2 is made of plastic, specifically polyethylene or polypropylene. In order to adapt to specific applications, polyethylene or polypropylene should meet non-toxic food grade requirements. The first protective layer 2 is tightly compounded with the metal pipe body 1 by means of a lining method, and the metal pipe body 1 of the aluminum alloy material can be strongly protected from the pipe material without any binder. The fluid phase is isolated, thus further protecting the metal pipe body 1. The thickness of the first protective layer 2 can be flexibly selected. The inner diameter of the first protective layer 2 determines the cross-sectional area of the fluid when it is transported inside the tube, and the outer diameter of the first protective layer 2 is generally smaller than the inner diameter of the metal tubular body 1 by 2 to 3 Glutinous rice is better.

Similarly, the second protective layer 3 is also a plastic material, specifically polyvinyl chloride, which is tightly laminated on the outer wall of the metal pipe body 1, so that the outer wall of the metal pipe body 1 is also protected from rust.

The manufacturing method of the village plastic pipe is embodied in the combination of the three-layer structure, which is different from the conventional production process in that the embryonic sample of the metal pipe body 1 of the present invention is subjected to cold drawing to cause radial deformation thereof. The metal tube is tightly fitted over the inner tube made of plastic, and the inner tube forms the first protective layer 2.

Specifically, both the first protective layer 2 and the second protective layer 3 can be bonded to the metal tube 1 in the same manner as described below.

First, the metal blank tube as the metal pipe body 1 is prepared in a predetermined size, here is an aluminum blank tube, and a polyethylene or polypropylene plastic endoderm, which is prepared as the first protective layer 2, a plastic endoderm sleeve In the aluminum embryo tube, the outer diameter of the plastic inner tube is smaller than the inner diameter of the aluminum tube by 2 to 3 mm, so as to be adapted to the mutual bonding during subsequent processing.

Then, the aluminum blank tube is forcibly stretched by a stretching machine through a die to reduce the radial size thereof to form an interference fit with the plastic endoderm, thereby forming a certain combination between the aluminum blank tube and the plastic endoderm. The force does not fall off, and stable compounding can be achieved without adding any adhesive.

Finally, after the aluminum blank tube and the plastic endoscopic tube are stretched and combined, the repeated aging treatment of - 20 ~ 100 degrees Celsius is used to remove the material processing stress and the residual internal stress, so that the plastic linear expansion system and the aluminum alloy are close to each other, thereby ensuring Within the normal operating temperature range (20 to 80 degrees Celsius), there is no delamination and stretching.

After the first composite layer 2 is closely combined with the metal pipe body 1, the polyvinyl chloride plastic eccentric tube as the second protective layer 3 and the metal pipe body 1 can be further used by referring to the above method. In combination, the metal-lined metal pipe of the present invention is formed.

It should be further emphasized that the materials used for the first protective layer 2 and the second protective layer 3 should not be limited by the embodiment, that is, the material of the second protective layer 3 can be made of polyethylene or polypropylene. Production.

The plastic-lined metal pipe of the invention can be widely applied to the fluid transportation of the water purification system, the building water supply system, and the food, medicine, brewing and the like industries, and can also be used as the gas transportation of the gas system, and the performance is safe and reliable.

The above description is only the preferred embodiment of the present invention, and the scope of protection of the present invention is not limited thereto, and those skilled in the art should know that equivalent changes or modifications in accordance with the scope of protection of the present invention should still be Within the scope of the invention.

Claims

Claim

1. A plastic-lined metal pipe for fluid transfer, comprising a metal pipe body, characterized in that: the inner wall of the metal pipe body (1) is tightly lined with a first protective layer (2), and the outer wall of the metal pipe body is The second protective layer (3) is coated.

The plastic-lined metal pipe according to claim 1, wherein the first protective layer (2) is made of a polyethylene or polypropylene material.

The plastic-lined metal pipe according to claim 1 or 2, wherein the second protective layer (3) is made of a polyvinyl chloride film.

The plastic-lined metal pipe according to claim 1 or 2, wherein the metal pipe body is made of an aluminum alloy pipe and is a seamless pipe body.

The metal-lined metal pipe according to claim 3, wherein the metal pipe body is made of an aluminum alloy pipe and is a seamless pipe body.

6. A method of manufacturing a metal-lined metal pipe, comprising the steps of: a. preparing a metal blank tube as the metal pipe body (1) and a plastic endoderm pipe as the first protective layer (2);

b. placing the plastic endoderm in the metal embryo tube, forcibly stretching the metal embryo tube, and reducing the radial size thereof to form an interference fit with the plastic endoderm;

The method of manufacturing a metal-lined metal pipe according to claim 6, wherein the specific temperature at the time of the aging treatment in the step c is -20 - 100 degrees Celsius.

The method of manufacturing a metal-lined metal pipe according to claim 6, wherein: the outer diameter of the plastic inner tube is 2-3 mm smaller than the inner diameter of the metal pipe.

The method for manufacturing a metal-lined metal pipe according to any one of claims 6 to 8, wherein: the metal blank tube material is made of aluminum alloy, and the material of the plastic inner tube is polyethylene or poly Propylene.

The method for manufacturing a metal-lined metal pipe according to claim 9, further comprising the step of: coating the outer surface of the metal blank tube with a plastic film as the second protective layer (2), made of polyvinyl chloride. And coated on the outer wall of the metal blank tube in the same process as steps a, b, and c.