Conical Acrylic Windows Under Long-Term Hydrostatic Pressure of 5000 psi

Conical acrylic windows with included angle 30 deg ≤ α ≤ 150 deg and thickness to minor diameter ratio of 0.375 ≤ t/D ≤ 1.00 have been subjected to 5,000 psi sustained hydrostatic loading of 1,000 hr duration in 65–75 deg F temperature range while the axial displacement of the windows through the flange has been monitored. The magnitude of axial displacement was found to be a function of α, t/D, temperature and duration of loading. Only windows with t/D ratios ≥1.000, 0.625, 0.500, 0.500, and 0.500 for 30, 60, 90, 120, and 150 deg conical angles, respectively, were found to be free of cracks. It is recommended that only windows with included angle α ≥ 60 deg be utilized for general service (long-term and cyclic) under 5,000 psi maximum hydrostatic pressure. The corresponding t/D ratios recommended for general service are 0.750 for α = 60 deg, and 0.625 for α ≥ 90 deg.