Deep Submergence Spherical Shell Window Assembly With Glass or Transparent Ceramic Windows for Abyssal Depth Service

Abstract

A total of 20 spherical shell windows with R0 = 4 in., Ri = 3 in., and 150 deg included spherical angle have been pressure tested under static and dynamic loading conditions. The tests included not only long term cyclic tests at 4500, 9000, 13,500, and 20,000 psi but also underwater shock tests at 450 psi static pressure. Two different gasket and four different transparent window materials were tested in the same metallic window flange with plane bearing surface. The transparent materials used in windows were glass ceramic CERVIT C-101, chemically surface compressed glass CERVIT SSC-201, borosilicate crown glass BK-7, and Plexiglas G acrylic plastic. The test results based on a total of over 10,000 hr of pressure testing indicate that the NUC 150 deg spherical shell window assembly design with t/Ri = 0.333 windows described in this paper can be routinely used in unmanned systems to any depth found in the ocean providing that the chemically surface compressed glass or transparent ceramic materials evaluated in this study are used in the assembly.