Storage tank with self-draining full-contact floating roof
View Patent ↗A storage tank with a full-contact floating roof is provided with automatic drains that have drain openings that are elevated above the top surface of the deck of the roof. Tilting mechanisms are used to tilt the deck toward the drains, causing liquid on the deck surface to pool at the drains, rising to the level of the drain openings. Cables connected to elevated portions of the tank can be used to tilt the deck from above, and landing supports can be used to tilt the deck from below.
1. A liquid storage tank that has a shell wall and a full-contact floating roof that has a single deck with a top surface and is designed to move vertically within the wall, floating upon the surface of product stored in the tank, the tank having:
at least one gravity drain on the roof with an opening spaced at a significant distance above the top surface of the single deck; and
a structure that enables the top surface of the single deck to be tilted toward the gravity drain opening.
2. A storage tank as recited in claim 1 , in which the roof is a pan roof with a peripheral rim.
3. A storage tank as recited in claim 1 , in which the roof is a bulkheaded roof with a peripheral open-top bulkhead compartment and a central open-top bulkhead compartment.
4. A storage tank as recited in claim 1 , in which the roof is a pontoon roof with a peripheral pontoon.
5. A storage tank as recited in claim 1 , in which the roof is a hybrid roof with a peripheral pontoon and a central open-top compartment.
6. A storage tank as recited in claim 1 , in which a central portion of the roof is no more than 2 inches thick.
7. A storage tank as recited in claim 1 , in which a central portion of the roof is no less than 1/32 inch thick.
8. A storage tank as recited in claim 1 , in which the roof is made primarily of steel and the height of a peripheral rim on the roof is no more than about 30″.
9. A storage tank as recited in claim 1 , in which the structure enables the deck to tilt on a plane.
10. A storage tank as recited in claim 1 , in which the structure enables the deck to tilt conically.
11. A storage tank as recited in claim 1 , in which the structure includes cables connecting different parts of the roof to elevated portions of the tank.
12. A storage tank as recited in claim 1 , in which the structure includes cables connecting different parts of the roof to an overhead fixed roof.
13. A storage tank as recited in claim 1 , in which the structure includes cables attached to different sections of the roof at different elevations.
14. A storage tank as recited in claim 1 , in which the structure includes self-coiling cables.
15. A storage tank as recited in claim 1 , in which the structure includes supports that extend from different parts of the bottom of the roof.
16. A storage tank as recited in claim 1 , in which the structure includes supports that extend from different parts of the bottom of the roof, different supports having different effective lengths.
17. A storage tank as recited in claim 1 , in which the structure includes supports that can be activated remotely to extend from different parts of the bottom of the roof.
18. A storage tank as recited in claim 1 , in which the structure includes supports that can be activated remotely to extend at different effective lengths from different parts of the bottom of the roof.
19. A storage tank as recited in claim 1 , in which the gravity drain opening is an automatic drain opening that is spaced from 2″ to 8″ above the top surface of the deck.
20. A storage tank as recited in claim 1 , in which the gravity drain opening is an automatic drain opening that is spaced from 3″ to 9″ above the bottom surface of the deck.
21. A storage tank as recited in claim 1 , in which the gravity drain opening is an automatic drain opening that is disposed near a peripheral rim of the roof.
22. A storage tank as recited in claim 1 that has a plurality of gravity drain openings spaced about the roof.
23. A storage tank as recited in claim 1 in which the gravity drain opening is an automatic drain opening and the tank also has at least one manual drain opening.
24. A storage tank as recited in claim 1 that also has a manual drain opening disposed near an outer rim.