Glass or Ceramic Spherical-Shell Window Assembly for 20,000-PSI Operational Pressure

The Naval Undersea Center NUC, working with a spherical-shell window with a 150- degree spherical angle and a matching compliant flange, has developed a window- flange assembly that uses a chemically surface-compressed glass or glass ceramic window and a Monel K-500 flange and is suitable for operational pressures up to 20,000-psi. A fiber-reinforced epoxy gasket cushions point contacts between the window and the flange. A Nylon clamp ring holds the window against the flange, while a Delrin ring attaches the flange to the hull. Hydrostatic testing has shown that the assembly, using a window with a thickness-to-inner-radius ratio of at least 0.333, has a minimum fatigue life of 300 cycles consisting of 4-hour pressurizations to 20,000-psi. Substitution of other materials in the window or bearing gasket reduces the fatigue life.