Abstract: An insulating polyolefin laminate paper and a method for producing such a paper in which first and second fiber paper layers are laminated to a polyolefin film layer. The fiber paper layers have an impermeability of 20 to 4000 Gurley-seconds. At least one of the fiber paper layers is mechanically deformed in such a manner that irregularities are produced having a depth of 2 to 50% of the thickness of the fiber paper layer. The mechanical deformation is accomplished prior to lamination. Before lamination, the water content of the fiber paper layers is controlled to be no more than 4%. Preferably, the thickness of the fiber paper layers is at least 30 microns. Furthermore, an electric power supply cable includes an insulating polyolefin laminate paper as an insulating layer.

Abstract: A composite pipe is proposed which is comprised of an aluminum pipe and a lead pipe formed in the aluminum pipe in direct contact with the inner wall of the aluminum pipe. The composite pipe is produced by supplying a lead pipe to a continuous aluminum extrusion machine which can extrude while enveloping along object, to form an aluminum pipe on the outer periphery of the lead pipe. A heat pipe using the composite pipe is also proposed.

Abstract: An insulating polyolefin laminate paper and a method for producing such a paper in which first and second fiber paper layers are laminated to a polyolefin film layer. The fiber paper layers have an impermeability of 20 to 4000 Gurley-seconds. At least one of the fiber paper layers is mechanically deformed in such a manner that irregularities are produced having a depth of 2 to 50% of the thickness of the fiber paper layer. The mechanical deformation is accomplished prior to lamination. Before lamination, the water content of the fiber paper layers is controlled to be no more than 4%. Preferably, the thickness of the fiber paper layers is at least 30 microns. Furthermore, an electric power supply cable includes an insulating polyolefin laminate paper as an insulating layer.

Abstract: A composite pipe is proposed which is comprised of an aluminum pipe and a lead pipe formed in the aluminum pipe in direct contact with the inner wall of the aluminum pipe. The composite pipe is produced by supplying a lead pipe to a continuous aluminum extrusion machine which can extrude while enveloping a long object, to form an aluminum pipe on the outer periphery of the lead pipe. A heat pipe using the composite pipe is also proposed.

Abstract: A composite pipe is proposed which is comprised of an aluminum pipe and a lead pipe formed in the aluminum pipe in direct contact with the inner wall of the aluminum pipe. The composite pipe is produced by supplying a lead pipe to a continuous aluminum extrusion machine which can extrude while enveloping a long object, to form an aluminum pipe on the outer periphery of the lead pipe. A heat pipe using the composite pipe is also proposed.This is a division of U.S. patent application Ser. No. 811,164, filed Dec. 19, 1985, now U.S. Pat. No. 4,733,699, issued Mar. 29, 1988.

Abstract: A composite pipe is proposed which is comprised of an aluminum pipe and a lead pipe formed in the aluminum pipe in direct contact with the inner wall of the aluminum pipe. The composite pipe is produced by supplying a lead pipe to a continuous aluminum extrusion machine which can extrude while enveloping a long object, to form an aluminum pipe on the outer periphery of the lead pipe. A heat pipe using the composite pipe is also proposed.

Abstract: An insulating polyolefin laminate paper and a method for producing such a paper in which first and second fiber paper layers are laminated to a polyolefin film layer. The fiber paper layers have an impermeability of 20 to 4000 Gurley-seconds. At least one of the fiber paper layers is mechanically deformed in such a manner that irregularities are produced having a depth of 2 to 50% of the thickness of the fiber paper layer. The mechanical deformation is accomplished prior to lamination. Before lamination, the water content of the fiber paper layers is controlled to be no more than 4%. Preferably, the thickness of the fiber paper layers is at least 30 microns. Furthermore, an electric power supply cable includes an insulating polyolefin laminate paper as an insulating layer.

Abstract: Improved composite pipes are proposed which comprise an outer pipe made of plastic and a thin lead layer on the inner wall of the outer pipe. The lead layer is formed by arranging a lead pipe in the outer pipe and expanding it by use of pressure medium into close contact with the inner wall of the outer pipe. The outer pipe may be circular or square or double-path. A process for producing the composite pipes is also proposed.

Abstract: A composite pipe is proposed which is comprised of an aluminum pipe and a lead pipe formed in the aluminum pipe in direct contact with the inner wall of the aluminum pipe. The composite pipe is produced by supplying a lead pipe to a continuous aluminum extrusion machine which can extrude while enveloping a long object, to form an aluminum pipe on the outer periphery of the lead pipe. A heat pipe using the composite pipe is also proposed.

Abstract: An oil-immersion electrically insulated cable of high performance is constructed by wrapping a conductor with insulation formed by winding on the conductor polypropylene film having a density in the range of 0.905 to 0.915 g/cm.sup.3, a birefringence in the range of 0.020 to 0.035, a ratio of strengths in two axial directions (tensile strength in the longitudinal direction/tensile strength in the lateral direction) in the range of 5 to 15, and impregnating the insulating layer with an insulating oil, preferably DDB oil.

Abstract: An insulating polyolefin laminate paper and a method for producing such a paper in which first and second fiber paper layers are laminated to a polyolefin film layer. The fiber paper layers have an impermeability of 20 to 4000 Gurley-seconds. At least one of the fiber paper layers is mechanically deformed in such a manner that irregularities are produced having a depth of 2 to 50% of the thickness of the fiber paper layer. The mechanical deformation is accomplished prior to lamination. Before lamination, the water content of the fiber paper layers is controlled to be no more than 4%. Preferably, the thickness of the fiber paper layers is at least 30 microns. Furthermore, an electric power supply cable includes an insulating polyolefin laminate paper as an insulating layer.

Abstract: A testing chamber for electrically testing a sample of insulating material or materials in sheet form, under controllable conditions of pressure and temperature. The pressure resistant chamber is air and liquid tight to permit testing of oil impregnated samples unexposed to harmful air. A frame is positioned within the chamber. A supply reel storing a test sample of insulating material or materials and a takeup reel for receiving the test sample drawn from the supply reel are both rotatably mounted on the frame. The supply and takeup reels are separated from each other to form a testing station therebetween. A shaft with a handle is attached to the takeup reel and extends out of the chamber to facilitate rotation of the takeup reel whereby the test sample may be removed from the supply reel to the testing station and then to the takeup reel. First and second electrodes are connected, respectively, to the high and low voltage terminals of a power supply.

Abstract: An electrically insulating laminate paper for an electric apparatus to be wound in a wet state on a conductive material and thereafter impregnated with oil, which is characterized by that water drops having a wide particle size distribution are scattered on the surface of the electrically insulating laminate paper comprising an integrated assembly composed of a plastic film and fiber papers bonded to each other to moisten said fiber papers.