| 摘要 |
A cover for a tank, hatch, or like container having an opening, including two rims about the perimeter of the opening connected by a flexible sleeve. At least one rim is rotatable with respect to the other, and, when rotated, causes the sleeve to close in an iris fashion and seal the opening. Reversing the rotation untwists the sleeve and causes the cover to open. The device of the present invention does not require sliding plates, cams or gears and is adaptable to closing about a pipe or other obstruction placed in the opening.
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