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An apparatus and method for continuously forming multi-layer metal pipe from at least two elongated sheets of metal. One sheet is impressed with longitudinal corrugations in a rolling device and the second sheet, being uncorrugated, is then positioned contiguously upon the first, forming a multi-lay

An apparatus and method for continuously forming multi-layer metal pipe from at least two elongated sheets of metal. One sheet is impressed with longitudinal corrugations in a rolling device and the second sheet, being uncorrugated, is then positioned contiguously upon the first, forming a multi-layer sheet. One or more removable modules is mounted in the rolling device to accurately align and guide the second sheet into position upon the first. Complementary portions of a single corrugation are then formed in the marginal edges of the multi-layer sheet and the sheet is spiralled into adjacent, helical convolutions in a pipe forming device, with the uncorrugated sheet forming the pipe interior. The adjacent convolutions are joined in a helical seam in the single corrugation by a seaming device located in the pipe forming device. In the primary embodiment of the invention, the seam is formed as a double lock seam along a neutral axis of the single corrugation.

대표청구항 ▼

In an apparatus for continuously forming multi-layer pipe from plural elongated sheets of ductile material, the pipe having a corrugated exterior wall and a substantially smooth interior wall, and the apparatus having a rolling device for positioning the sheets in contiguous layers and driving the s

In an apparatus for continuously forming multi-layer pipe from plural elongated sheets of ductile material, the pipe having a corrugated exterior wall and a substantially smooth interior wall, and the apparatus having a rolling device for positioning the sheets in contiguous layers and driving the sheets, a pipe forming device for accepting the drive sheets and spIralling the layered sheets into successive, adjacent helical convolutions having a central axis formed at an oblique angle to the longitudinal axis of the layered sheets, and a seaming device to join adjacent helical convolutions, the improvement comprising: a. first means in said rolling device for impressing continuous longitudinal corrugations in a first sheet forming the exterior wall of the pipe, b. second means in said rolling device for positioning a second flat sheet in a contiguous layer upon the first sheet, forming a multi-layer sheet, with the edges of said first and second sheets being generally coextensive, and c. means for forming a single, helical corrugation in the inner wall of the pipe, comprising i. first rolling means adjacent one marginal edge of said multi-layer sheet to shape therein a first portion of said single corrugation, said first rolling means including means to form a first partial lock seam element in said one marginal edge, ii. second rolling means adjacent the other marginal edge of said multi-layer sheet to shape therein a second portion of said single corrugation complementary to said first portion, said second rolling means including means to form a second partial lock seam element in said other marginal edge, iii. said first and second portions being joined by said seaming device to form said single corrugation. In an apparatus for continuously forming a multi-layer sheet from a plurality of elongated, continuous sheets of material, the apparatus having sources of first and second elongated sheets, a rolling device for forming longitudinal corrugations in the first sheet, and a device for guiding the second sheet into contiguous abutment with the corrugated first sheet, the improvement comprising: the guiding device including at least one module removably mounted in said rolling device, said module comprising a framework having mounted therein a pair of elongated pinch rolls positioned on opposite sides of the second sheet and a pair of edge guide rolls positioned at opposite edges of the second sheet, said pinch and guide rolls being located to maintain the second sheet vertically and laterally stable. A method of continuously forming multi-layer pipe from plural elongated sheets of material, the pipe having a helically corrugated exterior wall and a substantially smooth interior wall having a single, helical corrugation, including the steps of a. fashioning continuous longitudinal corrugations in a first sheet positioned for forming the exterior wall of the pipe, b. forming a multi-layer sheet by positioning a second flat sheet in a contiguous layer upon the first sheet with the edges of said first and second sheets being generally coextensive, c. shaping a first portion of said single corrugation in one marginal edge of said multi-layer sheet and shaping a first partial lock seam element in said one marginal edge, d. shaping a second portion of said single corrugation in the other marginal edge of said multi-layer sheet and shaping a second partial lock seam element in said other marginal edge, e. spiralling said multi-layer sheet into successive, adjacent helical convolutions having said first and second portions abutting to form said single corrugation, and f. joining the edges of said convolutions at the juncture of said abutting first and second portions by forming said partial lock seam elements into a helical seam located in said single corrugation.