Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
180 words
In a method of producing welded helical seam pipe from steel sheet wound into pipe formation, wherein prior to the welding of the wound sheet, an optically scannable reference line is applied to the steel sheet, which reference line extends parallel to and spaced from one of the edges of the sheet, and wherein the welding is effected by applying a first welding seam with a first welding head located within the pipe, and a second welding seam with a second welding head located outside the pipe, the improvement which comprises applying said optically scannable reference line to that face of the sheet which forms the inner surface of the welded pipe, optically scanning said reference line to obtain scanning information and controlling the welding movements of both said first and second welding heads in dependence on said scanning information, said wound sheet, after application of said reference line, being first tack-welded and then transferred to a finish welding station where the welding by means of said first and second welding heads is performed in dependence on said scanning information.
Claim 2
Dependent Claim
180 words
In a method of producing welded helical seam pipe from steel sheet wound into pipe formation, wherein prior to the welding of the wound sheet, an optically scannable reference line is applied to the steel sheet, which reference line extends parallel to and spaced from one of the edges of the sheet, and wherein the welding is effected by applying a first welding seam with a first welding head located within the pipe, and a second welding seam with a second welding head located outside the pipe, the improvement which comprises applying said optically scannable reference line to that face of the sheet which forms the inner surface of the welded pipe, optically scanning said reference line to obtain scanning information and controlling the welding movements of both said first and second welding heads in dependence on said scanning information, said wound sheet, after application of said reference line, being first tack-welded and then transferred to a finish welding station where the welding by means of said first and second welding heads is performed in dependence on said scanning information.
Claim 3
Independent Claim
124 words
A method of producing welded helical seam pipe from steel sheet which comprises: a. applying an optically scannable reference line to that face of the steel sheet which in the final pipe forms the inner surface; b. helically winding the steel sheet into pipe formation; c. tack-welding opposing edges of the wound sheet at spaced locations; d. moving the tack-welded pipe formation to a finish welding station; e. applying a first welding seam from the inside with a first welding head and thereafter applying a second welding seam from the outside with a second welding head and optically scanning said reference line and controlling the movements of said first and second welding heads in dependence on the scanning information obtained by said optical scanning.
Claim 4
Independent Claim
124 words
A method of producing welded helical seam pipe from steel sheet which comprises: a. applying an optically scannable reference line to that face of the steel sheet which in the final pipe forms the inner surface; b. helically winding the steel sheet into pipe formation; c. tack-welding opposing edges of the wound sheet at spaced locations; d. moving the tack-welded pipe formation to a finish welding station; e. applying a first welding seam from the inside with a first welding head and thereafter applying a second welding seam from the outside with a second welding head and optically scanning said reference line and controlling the movements of said first and second welding heads in dependence on the scanning information obtained by said optical scanning.
Claim 5
Dependent Claim
53 words
A method as claimed in claim 2, wherein said second welding seam is applied by said second welding head after the first welding seam has been applied and optically scanned, the movement of said second welding head also being controlled in dependence on the scanning information obtained by scanning said first welding seam.
Claim 6
Dependent Claim
23 words
A method as claimed in claim 2, wherein the pipe formation is cut into lengths after the tack-welding and prior to step d.