Metal-plastic multilayer pipe with a plastic inner pipe (30) and a metal sheath (32) around the plastic inner pipe (30), where the metal sheath (32) is of uniform thickness, is applied to the plastic inner pipe (30) so that it completely encircles the plastic inner pipe (30) and a practical plastic outer layer (38), with the feature that the thickness of the metal sheath (32) as compared to the total thickness of all layers of the multilayer pipe (32, 34 and 38), is sufficiently thin that the metal sheath (32) accounts for a negligible part of the overall strength and stiffness of the multilayer pipe and, as a consequence, when the multilayer pipe is bent in an arc, the metal sheath (32) offers negligible resistance to such bending as compared to the resistance offered by the inner pipe (30) and the practical cover layer (38), and when so bent, the multilayer pipe tends to remain bent in said arc, whereby, the multilayer pipe has "form stability".
A hose for feeding cold or hot water, which can be easily bent even at a small radius so that it can be applied in a small piping space, which is free of kink, and which can accommodate running water containing chlorine, is provided. The hose for feeding cold or hot water includes: an inner layer formed of an elastic tube; an inner reinforcing layer formed of a fiber yarn wound in a spiral provided on the inner layer; and an outer reinforcing layer formed of a woven metallic hard wire provided on the inner reinforcing layer.
A multilayer pipe which comprises at least an inner layer and an outer layer. The inner layer is made of extrudable plastic, such as polyethylene PE, cross-linked polyethylene PEX or polypropylene PP. The outer layer forms a fire-protecting layer and the matrix plastic of the outer layer is also made of extrudable plastic. A foaming agent, which does not react during the manufacture of the pipe, is mixed with the matrix. Further, the outer layer contains at least one additive in such a manner that the outer layer has a pipe-reinforcing component and a fire-retardant component. Most preferably, at least the outer layer is extruded by an extruder having a screw length ratio of less than 10 to its biggest diameter.
