Patent ID: 7434396

Claim:
A buoyancy driven apparatus, comprising: a tank; a column of liquid contained within said tank; a plurality of liquid displacers connected to form an endless chain; an airlock means comprising a variable geometry inflatable seal for admitting said displacers of said chain sequentially into the lower portion of said column of liquid; said variable geometry inflatable seal of said airlock means comprises sealing means for minimizing the amount of liquid escaping from said tank as each of said displacers enter said column of liquid; said sealing means includes a plurality of said variable geometry inflatable seals, each configured as a doughnut with a hole who's dimensions vary as a function of pneumatic pressure within said doughnut structure; and means to guide said endless chain from the bottom to the top of said column of liquid and externally of said column of liquid from the top to the bottom thereof whereby each of said liquid displacers comprising said endless chain sequentially enter a lower section of said column of liquid via said airlock and exit the top of said column of liquid.