Apparatus for and the method of making spiral seamed laminated sheet metal pipe

Claim 3

A method as claimed in claim 1 in which the mandrel is recessed in the region of said seaming rolls wherein the laminate is dented in that region by the seaming rolls and subsequently restored to the same diameter as the mandrel.

Claim 4

A method as claimed in claim 1 in which the front edge seam configuration is rolled to the form of a groove defined by a flange upstanding from the uncorrugated side of the laminate and at the extreme edge of the strips, a base in a plane generally parallel to the plane of the strips, and a wall upstanding from the corrugated side of the laminate, the base interconnecting the wall and the flange; the back edge seam configuration is rolled to form a flange upstanding from the corrugated side of the laminate, the laminate is lain on the mandrel so that the back edge flange is located within the front edge groove and the seam is locked in a single operation by seaming rolls rotatable about axes normal to the seam.

Claim 5

A method as claimed in claim 1 in which the front edge seam configuration is rolled to the form of a groove defined by a flange upstanding from the uncorrugated side of the laminate and at the extreme edge of the strips, a base in a plane generally parallel to the plane of the strips, and a wall upstanding from the corrugated side of the laminate, the base interconnecting the wall and the flange; the back edge seam configuration is rolled to form a flange upstanding from the corrugated side of the laminate, the laminate is lain on the mandrel so that the back edge flange is located within the front edge groove and the seam is locked in a single operation by seaming rolls rotatable about axes normal to the seam, the base of the groove forming the radially outermost portion of the locked seam.

Claim 6

Apparatus for making spirally seamed laminated sheet metal pipe having an outer lamina of corrugated strip and an inner lamina of uncorrugated strip, which comprises individual rolling mills for each of said corrugated and uncorrugated strips, said mills including front and rear edge forming rolls of matching sections for the two strips, means matching and uniting the strips thus formed into a laminate, a fixed cylindrical mandrel, and means for laying the laminate spirally on the mandrel with the back edge configuration of one convolution of convolutions thus lain on the mandrel, within the front edge configuration of a succeeding convolution, two cooperating seaming rolls one located within the mandrel and engaging the combined seam edge configurations through an opening in that mandrel and the other located outside the mandrel and engaging the combined seam edge configurations on the opposite side to said first seaming roll.

Claim 7

Apparatus for making spirally seamed laminated sheet metal pipe having an outer lamina of corrugated strip and an inner lamina of uncorrugated strip, which comprises individual rolling mills for each of said corrugated and uncorrugated strips, said mills including front and rear edge forming rolls of matching sections for the two strips, means matching and uniting the strips thus formed into a laminate, a fixed cylindrical mandrel, and means for laying the laminate spirally on the mandrel with the back edge configuration of one convolution of convolutions thus lain on the mandrel, within the front edge configuration of a succeeding convolution, two cooperating seaming rolls one located within the mandrel and engaging the combined seam edge configurations through an opening in that mandrel and the other located outside the mandrel and engaging the combined seam edge configurations on the opposite side to said first seaming roll.

Claim 8

Apparatus as claimed in claim 5 in which the mandrel is recessed in the region of said seaming rolls.

Claim 9

Apparatus as claimed in claim 6 in which said recess extends partially around the outer surface of the mandrel in the direction in which the laminate is lain upon that mandrel and is progressively less shallow in the direction of progression of the laminate upon the mandrel.

Claim 10

Apparatus as claimed in claim 5, in which the seaming roll outside the mandrel is formed with a circumferential groove within which the material of the seam is pressed.