GB901126A - Metallic pipes lined with glass - Google Patents

Abstract

901,126. Lining metal pipes. TANAKA, S. May 31, 1960 [June 18, 1959], No. 19193/60. Class 99(2). A metallic pipe 1 lined with a glass pipe 3 has an inorganic, heat resisting buffer layer 2 having a fusion point below that of the pipes 1, 3 interposed between them, the pipes and buffer layer being heated together to the softening temperature of the glass pipe, and immediately expanded by blowing high pressure gas to fill the softened glass pipe which simultaneously renders the pipes 1, 3 and the buffer layer 2 into one body under pressure, a relatively low compressive stress being imparted to the glass pipe by the metal pipe during the cooling thereof. As shown, the glass pipe 3 is inserted in the metal pipe 1 after the inner surface of the pipe has been roughened by emery blasting and coated with a slurry of the buffer layer material and water. One end of the pipe 3 is closed by fusion, and the other is provided with a flange 5 which is hermetically sealed by a rubber board 7 interposed between clamping boards 6 and 8. The assembly is heated, e.g. by an induction furnace 10 to the softening point of the pipe 3 when gas under pressure is passed through a feed pipe 9, which forces the glass pipe to adhere via the buffer layer 2 to the pipe 1. The excess glass portions are cut off after the metal pipe has cooled. The buffer layer comprises sodium oxide, lead oxide, silicon dioxide and boron oxide, which may be mixed with a metal salt that on heating generates gas. In this latter case a number of fine bubbles are present in the buffer layer.