Hatch Seal Design Parameters for Manned Submersibles

Southwest Research Institute conducted a test program on the 26-inch diameter hatch seal o-ring for a manned submersible vehicle. The tests measured o-ring extrusion at pressure differentials across the seal of up to 1560 psig and gaps between the sealing surfaces of up to 0.110 inches. This paper presents a test protocol for determining the maximum gap that a given size o-ring can seal at a given pressure. This paper also presents charts of extrusion vs. seal gap and addresses the potential for o-ring damage when the sealed joint is depressurized. The test results were used in the design of the hatch seal for the U.S. Navy Pressurized Rescue Module and represent the first industry-wide o-ring design data for face seals in large diameter mechanical joints that do not close with pressure.