CN2456860Y

CN2456860Y - Double layer screw welded tube

Info

Publication number: CN2456860Y
Application number: CN 00257959
Authority: CN
Inventors: 凌星中
Original assignee: Individual
Current assignee: Individual
Priority date: 2000-10-20
Filing date: 2000-10-20
Publication date: 2001-10-31
Anticipated expiration: 2010-10-20

Abstract

The utility model discloses a double-layer tube, particularly the technical field of a welded steel tube. The utility model is mainly characterized in that inner-layer tubes and outer-layer tubes are spiral welded tubes, the inner-layer tubes are tightly expanded and stuck together by a mechanical tube expander without gaps, and the spiral welds of the inner-layer tubes and the outer-layer tubes are in dislocated arrangement with each other. The utility model is suitable for conveying fluids comprising petroleum, natural gas, etc. A double-layer screw welded tube has higher strength and anti-brittle fracture capability than that of a single-layer tube so as to enhance the using safety and economy of pipelines, and the double-layer screw welded tube can be organized and produced by the existing spiral welded tube producing machine.

Description

The double-layer spiral welded tube

The utility model relates to the metal mold welded tube

The welded tube that uses in oil, the isometric defeated pipeline of natural gas all is the spiral welded pipe and the ERW of individual layer.Require to use the pipe of big caliber, high-strength thick when high pressure, big flow volume delivery fluid, make this welded tube and then require to possess large-scale, powerful tubulation equipment, it is very huge to build such equipment investment.Along with the raising of tubing intensity rank, and the wall thickness increase, the danger of its brittle break also increases.

The purpose of this utility model is to provide a kind of spiral welded pipe of bilayer, and this double-layer spiral welded tube can utilize existing spiral tuber to produce thick-walled pipe, and further improves security and economy that fluid feed line is used.

The utility model is to utilize existing spiral tuber to produce two kinds of different pipes of caliber.A kind of internal diameter of pipe (1) is greater than the external diameter (2) of another kind of pipe.In the process of tubulation welding, the height that thickens that thickens height and tubule outer wall weld seam (4) of big inside pipe wall weld seam (3) is planished, also can be with T ig or plasma etc. from fusion welding.Two pipe boxes that such diameter is not waited and arrange both spiral weld dislocation together, use the mechanical expander hole enlargement.Both are fitted tightly form bimetallic tube.

The utility model is again a double-decker owing to adopt the cut deal tubulation, and the weld seam dislocation arranges that welded tube intensity and anti-brittle break ability all are higher than the individual layer welded tube.Therefore under the certain condition of fluid conveying pressure and caliber, the pipe thickness of bimetallic tube is thinner than mono-layer tube, under the certain condition of caliber and wall thickness, bimetallic tube can have higher fluid conveying pressure, and this has just improved the security and the economy of fluid-carrying lines.

With regard to China's national situation, have superfluous spiral welded pipe manufacturing capacity, and do not have big caliber heavy wall ERW manufacturing capacity, therefore can utilize the double-layer spiral welded tube to substitute big caliber, the ERW of heavy wall.

Fig. 1 is a kind of double-layer spiral welded tube structure chart of the present utility model.

Fig. 2 is the left view of Fig. 1

The embodiment of the utility model double-layer spiral welded tube is: with the thick hot rolled strip moulding on the spiral tuber of 8mm, through being welded into diameter is respectively the spiral welded pipe (1) of 720mm and the spiral welded pipe (2) that diameter is 694mm automatically.The external spiral out-seam that the spiral inseam of φ 720 pipes thickens height and φ 694 in automatic welding process thickens height and is all dug, φ 694 pipe boxes are gone in φ 720 pipes, and the spiral weld of two pipes is misplaced 180 °, the pipe hole enlargement that will assemble with mechanical expander, pipe is close on the inwall of outer tube in making, and promptly makes the double-layer spiral welded tube.

Claims

1. metal bi spiral welded pipe, it is characterized in that: (1) internal layer and outer tube all are spiral welded pipes of being made by carbon steel or low alloy steel, (2) the spiral inside weld of the spiral outside weld of interior pipe and outer tube does not have the height of thickening, (3) pipe and outer tube are gapless tight fit in, manage in (4) and the spiral weld of the outer tube layout that misplaces each other.