Importance

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Abstract

A submarine periscope system has a mast head 7 with a casing 10 from which protrudes a shaft 16 carrying observation instruments which are protected by a housing 8. A seal arrangement 30 is provided at the interface between the casing 10 and shaft 16 which imposes low friction torque at water pressures within the operational depth range of the periscope system and permits the shaft 16 to rotate for azimuthal movement of the observation instruments. A rotary drive 14 is connected to the shaft 16 for this purpose. The seal arrangement 30 imposes high friction torque at water pressures outside the operational depth range of the periscope system and a water depth pressure valve disables the shaft rotary drive to provide integrity of the seal arrangement outside the operational depth range. The mast head 7 is telescopically extendable by a hoist device 13 and does not penetrate the hull 2 of the submarine 3.

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First Claim