US4036394A — Floating roof for liquid storage tanks

Claim 1

Independent Claim 98 words

A floating roof for a liquid storage tank comprising a single-deck lid of a plurality of fluid-tight interconnected rectangular steel plates and auxiliary means for imparting buoyancy to the lid including a plurality of elongate buoys of low silhuouette on the upper surface of the lid, each buoy having as its base one of the plates and having longitudinal sides inclined toward each other and the base, such that the buoy is of increasingly smaller horizontal section from its base to its top and of such construction as to stiffen the junctions between the buoy and adjacent plates.

Claim 2

Dependent Claim 98 words

A floating roof for a liquid storage tank comprising a single-deck lid of a plurality of fluid-tight interconnected rectangular steel plates and auxiliary means for imparting buoyancy to the lid including a plurality of elongate buoys of low silhuouette on the upper surface of the lid, each buoy having as its base one of the plates and having longitudinal sides inclined toward each other and the base, such that the buoy is of increasingly smaller horizontal section from its base to its top and of such construction as to stiffen the junctions between the buoy and adjacent plates.

Claim 3

Dependent Claim 154 words

A relatively large floating roof for a liquid storage tank comprising a single-deck lid of a plurality of fluid tight interconnected generally rectangular steel plates adapted to be disposed in liquid contact with the liquid stored in said tank and auxiliary means for imparting buoyancy to the lid including a plurality of elongated buoys of low silhouette on the upper surface of the lid, each buoy having as its base substantially the entire area of one of the plates, and having longitudinal sides inclined toward each other and the base such that the buoy is of increasingly smaller horizontal section from its base to its top, with the longest dimension of the respective buoys being parallel to the junctions of its base plate and the steel plates adjacent thereto, said elongated buoys being distributed over the lid with their lengths in parallel to stiffen the junctions between each buoy base plate and adjacent plates.

Claim 4

Dependent Claim 154 words

A relatively large floating roof for a liquid storage tank comprising a single-deck lid of a plurality of fluid tight interconnected generally rectangular steel plates adapted to be disposed in liquid contact with the liquid stored in said tank and auxiliary means for imparting buoyancy to the lid including a plurality of elongated buoys of low silhouette on the upper surface of the lid, each buoy having as its base substantially the entire area of one of the plates, and having longitudinal sides inclined toward each other and the base such that the buoy is of increasingly smaller horizontal section from its base to its top, with the longest dimension of the respective buoys being parallel to the junctions of its base plate and the steel plates adjacent thereto, said elongated buoys being distributed over the lid with their lengths in parallel to stiffen the junctions between each buoy base plate and adjacent plates.

Claim 5

Dependent Claim 18 words

A floating roof according to claim 2, in which the respective buoys have heights less than their widths.

Claim 6

Dependent Claim 18 words

A floating roof according to claim 2 in which the lid includes an annular pontoon about its perimeter.

Claim 7

Dependent Claim 15 words

A floating roof according to claim 2 in which said buoys have curved outer surfaces.

Claim 8

Dependent Claim 23 words

A floating roof according to claim 5 in which said buoys are in the form of less than a half cylinder of revolution.

Claim 9

Dependent Claim 235 words

In a relatively large liquid storage tank floating roof of single-deck lid construction, wherein said lid is of the type formed by the interconnection of a plurality of generally rectangular, substantially uniformly-sized fluid tight plates by welding or the like, said roof having a lower surface adapted to contact and float upon the top surface of said liquid contents in an essentially flat contacting relationship, and having a plurality of auxiliary buoy means arranged upon the upper surface of the roof in substantially uniformly distributed relationship to provide floating support of the roof in the event of deck puncture or precipitation loading, the improvement comprising: each of said plurality of buoys including a base comprising substantially the entire surface of one of the plurality of plates forming the upper surface of said deck lid and further including structure attached to said base above the upper surface of said deck lid to form a closed buoy, each of said plurality of buoys being of increasingly smaller horizontal section from the bottom to the top of said buoys, each of said plurality of buoys having a length greater than its width, and a width greater than its height as measured in a perpendicular vertical plane to effect a relatively long and low buoy silhouette and impart stiffening to the interconnection junctions paralleling the longest dimension of said buoy between each buoy base plate and its adjacent plates.

Claim 10

Dependent Claim 235 words

In a relatively large liquid storage tank floating roof of single-deck lid construction, wherein said lid is of the type formed by the interconnection of a plurality of generally rectangular, substantially uniformly-sized fluid tight plates by welding or the like, said roof having a lower surface adapted to contact and float upon the top surface of said liquid contents in an essentially flat contacting relationship, and having a plurality of auxiliary buoy means arranged upon the upper surface of the roof in substantially uniformly distributed relationship to provide floating support of the roof in the event of deck puncture or precipitation loading, the improvement comprising: each of said plurality of buoys including a base comprising substantially the entire surface of one of the plurality of plates forming the upper surface of said deck lid and further including structure attached to said base above the upper surface of said deck lid to form a closed buoy, each of said plurality of buoys being of increasingly smaller horizontal section from the bottom to the top of said buoys, each of said plurality of buoys having a length greater than its width, and a width greater than its height as measured in a perpendicular vertical plane to effect a relatively long and low buoy silhouette and impart stiffening to the interconnection junctions paralleling the longest dimension of said buoy between each buoy base plate and its adjacent plates.

Claim 11

Dependent Claim 196 words

A floating roof for a liquid storage tank, comprising in combination: means for covering the liquid contents of said storage tank including a lid structure comprising a plurality of fluid tight interconnected plates of fluid tight material, said lid structure having a lower surface adapted to contact the top surface of said liquid contents in an essentially flat contacting relationship; and means for imparting buoyancy to said lid structure including a plurality of buoys, at least a majority of which include a base consisting substantially of a different one of said plates; and further including structure attached to each said buoy base having at least two sides inclined relative to a perpendicular plane through said lid structure and inclined toward each other as seen from the lid structure, said buoy structure having a convex outer surface extending through said plane and having a length greater than its width to effect a relatively long and low silhouette and impart stiffening to the interconnection junctions paralleling the longest dimension of said buoy between each buoy base plate and its adjacent plates, said buoys of at least a majority of buoys being located opposite said lower liquid contacting surface.

Claim 12

Dependent Claim 196 words

A floating roof for a liquid storage tank, comprising in combination: means for covering the liquid contents of said storage tank including a lid structure comprising a plurality of fluid tight interconnected plates of fluid tight material, said lid structure having a lower surface adapted to contact the top surface of said liquid contents in an essentially flat contacting relationship; and means for imparting buoyancy to said lid structure including a plurality of buoys, at least a majority of which include a base consisting substantially of a different one of said plates; and further including structure attached to each said buoy base having at least two sides inclined relative to a perpendicular plane through said lid structure and inclined toward each other as seen from the lid structure, said buoy structure having a convex outer surface extending through said plane and having a length greater than its width to effect a relatively long and low silhouette and impart stiffening to the interconnection junctions paralleling the longest dimension of said buoy between each buoy base plate and its adjacent plates, said buoys of at least a majority of buoys being located opposite said lower liquid contacting surface.

Claim 13

Dependent Claim 21 words

A floating roof as claimed in claim 8, wherein: said buoy structure has a height which is less than its width.

Claim 14

Dependent Claim 24 words

A floating roof as claimed in claim 8, wherein: each of said buoys of at least a majority of buoys includes a dished shell.

Claim 15

Dependent Claim 19 words

A floating roof as claimed in claim 8, including: an annular buoy at the periphery of said lid structure.

Claim 16

Dependent Claim 20 words

A floating roof as claimed in claim 8, wherein: said covering means include peripheral seal means on said lid structure

Claim 17

Dependent Claim 24 words

A floating roof as claimed in claim 8, wherein: said buoys of at least a majority of buoys are distributed over said lid structure.

Claim 18

Dependent Claim 34 words

A floating roof as claimed in claim 8, wherein: each of said buoys of at least a majority of buoys includes a hollow-cylindrical shell having its elemental line essentially parallel to said lid structure.

Claim 19

Dependent Claim 20 words

A floating roof as claimed in claim 14, wherein: each of said hollow-cylindrical shells is less than a half cylinder.

Claim 20

Independent Claim 244 words

A method of minimizing fatigue cracking due to wind action upon a floating roof for a liquid storage tank of the type wherein the floating roof comprises a lid formed by the interconnection of a plurality of fluid tight plates by welding or the like, said roof having a plurality of buoy means arranged upon the upper surface of the roof to provide floating support of the roof in the event of deck puncture or precipitation loading, comprising the steps of: constructing each of said plurality of buoys to have a base consisting substantially of a different one of said plurality of plates forming said lid, and further including structure attached to said base upon said deck lid to form a closed buoy of increasingly smaller horizontal section from the base to the top of said buoys, each of said buoys having a length greater than its width, and a width greater than its height to effect a relatively long and low buoy silhouette and impart stiffening to the interconnection junctions paralleling the longest dimension of said buoy between each buoy base plate and its adjacent plate, and orienting said lid structure within said storage tank with the lower surface thereof adapted to contact the top surface of said liquid contents in an essentially flat contacting relationship and with the longest dimension of each of said plurality of buoys being essentially parallel to the prevailing wind direction at the site of the storage tank.

Claim 21

Independent Claim 244 words

A method of minimizing fatigue cracking due to wind action upon a floating roof for a liquid storage tank of the type wherein the floating roof comprises a lid formed by the interconnection of a plurality of fluid tight plates by welding or the like, said roof having a plurality of buoy means arranged upon the upper surface of the roof to provide floating support of the roof in the event of deck puncture or precipitation loading, comprising the steps of: constructing each of said plurality of buoys to have a base consisting substantially of a different one of said plurality of plates forming said lid, and further including structure attached to said base upon said deck lid to form a closed buoy of increasingly smaller horizontal section from the base to the top of said buoys, each of said buoys having a length greater than its width, and a width greater than its height to effect a relatively long and low buoy silhouette and impart stiffening to the interconnection junctions paralleling the longest dimension of said buoy between each buoy base plate and its adjacent plate, and orienting said lid structure within said storage tank with the lower surface thereof adapted to contact the top surface of said liquid contents in an essentially flat contacting relationship and with the longest dimension of each of said plurality of buoys being essentially parallel to the prevailing wind direction at the site of the storage tank.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1980-07-18	1981-01-17	1981-07-19	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1984-07-18	1985-01-17	1985-07-19	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1988-07-18	1989-01-17	1989-07-19	$7700.00	Window Closed / Lapsed

Floating roof for liquid storage tanks

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