Screen manufacturing method and welding apparatus thereof

Abstract

The present invention relates to a method for manufacturing a screen and welding apparatus thereof, putting a metal filter net around the outside of a support sheath and fixing the metal filter net to the outside of the support sheath by way of welding, such that the metal filter net completely covers all filter holes of the support sheath to form a filter sheath with; fixing the filter sheath to the outside of the base pipe and the filter sheath completely covering all penetrated holes on the base pipe; putting a jacket around the outside of the filter sheath and fixing it to the outside of the base pipe such that the jacket completely covers the outside surface of the filter area of the filter sheath. The present invention uses direct spot welding and seam welding technology to fix the metal net to the outside of the support sheath directly, eliminates leakage hole phenomena appearing on jointing parts of the metal net and forms the screen with multi-layer metal nets with improved sand control capability and life time. The present invention also discloses the apparatus for above-said screen to realize penetrated welding of the filter sheath so as to improve the welding quality of the metal net and lower the factory cost of the screen.

Description

CROSS-REFERENCE TO RELATED PATENT APPLICATIONS[0001]The present application is a divisional application of U.S. application Ser. No. 11 / 362,282, filed Feb. 27, 2006, the entire contents of which is incorporated herein by reference in its entirety.FIELD OF THE INVENTION[0002]The present invention relates to a method for manufacturing screen (or sieve tube) and welding apparatus thereof, particularly to a method for manufacturing screen made of filtering material including metal net by resistance spot welding or seam welding technology and welding apparatus thereof. It belongs to petroleum exploitation field.BACKGROUND OF THE INVENTION[0003]In petroleum and natural gas exploitation fields, in order to prevent sand in the oil-gas well from being brought to shaft or ground apparatuses together with oil-gas-water while sanding, in-well screen which could effectively filtrates oil-gas-water needed to be used. One hole in a segment of an in-well screen ranged from several decades to severa...

AI Technical Summary

Benefits of technology

[0007]One object of the present invention is to provide a method for screen manufacturing and welding apparatus thereof, which uses resistance spot welding or seam welding technology to directly combine metal nets and connect them to base pipe etc, so as to eliminate leakage hole phenomena occurring at welding part of metal net, and form a screen from multilayer metal net with improved sand control capacity and life time.

[0008]Second object of the present invention is to provide a method for screen manufacturing and welding apparatus thereof to improve welding quality of metal net and lower factory cost of screen by way of two-side one-point welding.

[0017]The present invention utilizes resistance spot welding or seam welding technology to directly combine metal net. Actually the combination is to fix multilayer of metal net together and connect it with the base pipe etc, so as to eliminate leakage hole phenomena appeared on jointing parts of the metal net and form the screen with multilayer metal nets and improve sand-control and life time. In addition, the present invention uses direct welding method to improve the welding quality of the metal net and lower the factory cost of the screen.

Problems solved by technology

At present, most of filter materials used to make premium screen are very expensive multi-layer sintered metal net.

However, the filter material has high factory cost, low productivity and its size is limited by vacuum welding apparatus.

However, conventional welding technology has either low welding strength or leak phenomena (shrinkage hole phenomena) appears on welding parts of melt net.

However, the strength and reliability produced by these methods are relative low.

Although the screen may be made of non-sintered multi-layer composite net, during welding, shrinkage hole phenomena of multi-layer compound net is more serious than single-layer metal net.

At the same time, due to high thickness of screen and several-meter-long filter segment, series of difficulties are brought to welding procedure.

Thus how to obtain high quality and low cost screen welded by way of welding method from metal net is one big problem in the field.

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