Pipe with crack stopper feature, and process of protecting a pipe against propagation of cracks
AssigneeMannesmann Aktiengesellschaft
InventorsHans-Georg Hillenbrand, Ingo Von Hagen, Gerd Junker, Gerhard Knauf, Johannes Arndt
Life of this patent
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Abstract
A steel pipe, includes an outer corrosive-preventive protective sheath, which has a surface layer of plastic material, and a crack stopper zone extending over a section of the pipe. The crack stopper zone includes a bandage which is wrapped around the pipe section and made of high-strength fiber material imbedded in a compacted matrix of thermoplastic and thermosetting plastic. The bandage is comprised of a plurality of wound layers joined to one another via the matrix by welding or gluing.
Claims34
A steel pipe, comprising an outer corrosion-preventive protective sheath, which includes a surface layer of plastic material, and a crack stopper zone, which extends over a portion of a length of the pipe, said crack stopper zone formed by a bandage wrapped around the pipe and made of high-strength fiber material imbedded in a compacted matrix of a plastic selected from the group consisting of thermoplastic and thermosetting plastic, said bandage comprised of a plurality of wound layers joined to one another via the matrix by a process selected from the group consisting of welding and gluing.
A process of making a pipe with a crack stopper zone, comprising the steps of:
- applying a corrosion-preventive protective plastic sheath upon a clean surface of a steel pipe;
- wrapping the pipe in several layers with a band material made of high-strength fiber material imbedded in a matrix of a plastic selected from the group consisting of thermoplastic and thermosetting plastic, with the number of layers being so selected that the band material reliably withstands maximum tensile stress when the pipe cracks during operation;
- and
- cooling the band material to ambient temperature.
A process of making a pipe with a crack stopper zone, comprising the steps of:
- wrapping a steel pipe in several layers with a bandage made of high-strength fiber material imbedded in a matrix of a plastic selected from the group consisting of thermoplastic and thermosetting plastic, with the number of layers being so selected that the bandage reliably withstands maximum tensile stress when the pipe cracks during operation;
- applying a corrosion-preventive protective plastic sheath upon the bandage;
- and
- cooling the bandage to ambient temperature.
A crack stopper for attachment to a pipe section, comprising a bandage intended for wrapping the pipe section in several layers and made of high-strength fiber material imbedded in a compacted matrix of a plastic selected from the group consisting of thermoplastic and thermosetting plastic, wherein wound layers of the bandage are joined together by a process selected from the group consisting of welding and gluing, wherein the fiber material is under initial tensile stress.
A crack stopper for attachment to a pipe section, comprising a bandage intended for wrapping the pipe section in several layers and made of high-strength fiber material imbedded in a compacted matrix of a plastic selected from the group consisting of thermoplastic and thermosetting plastic, wherein wound layers of the bandage are joined together by a process selected from the group consisting of welding and gluing, wherein the bandage has an axial length which is at least 0.5×D, wherein D is a diameter of the pipe section.
A crack stopper for attachment to a pipe section, comprising a bandage intended for wrapping the pipe section in several layers and made of high-strength fiber material imbedded in a compacted matrix of a plastic selected from the group consisting of thermoplastic and thermosetting plastic, wherein wound layers of the bandage are joined together by a process selected from the group consisting of welding and gluing, wherein the bandage has a thickness of at least 5 mm.
A process of protecting a pipe against propagation of cracks, comprising the step of wrapping a pipe section in several layers with a bandage made of high-strength fiber material imbedded in a matrix of a plastic selected from the group consisting of thermoplastic and thermosetting plastic, wherein wound layers of the bandage are joined together by a process selected from the group consisting of welding and gluing, wherein the matrix is made of thermoplastic, and further comprising the step of heating the matrix immediately before the wrapping step to effect a fusion of individual layers through at least partial melt-on of the matrix.
A process of protecting a pipe against propagation of cracks, comprising the step of wrapping a pipe section in several layers with a bandage made of high-strength fiber material imbedded in a matrix of a plastic selected from the group consisting of thermoplastic and thermosetting plastic, wherein wound layers of the bandage are joined together by a process selected from the group consisting of welding and gluing, wherein the wrapping step is carried out with the fiber material at an initial tensile stress.
A process of protecting a pipe against propagation of cracks, comprising the step of wrapping a pipe section in several layers with a bandage made of high-strength fiber material imbedded in a matrix of a plastic selected from the group consisting of thermoplastic and thermosetting plastic, wherein wound layers of the bandage are joined together by a process selected from the group consisting of welding and gluing, wherein the wrapping step is carried out by winding the bandage at least ten times around the pipe section.
Dependencies are inferred from the claim text.