US2873042A - Adjustable floating roof - Google Patents

Description

Feb. 10, 1959 A. F. FINO ADJUSTABLE FLOATING ROOF 2 Sheets-Sheet 1 Filed NOV. 19, 1956 FEG.!

202s 22 is INVENTOR. mexnder F. Fmo

.32 F i G /29 /40a vUnited Sttcs atcnt O 2,873,042 Patented Feb. 10, 1959 ADJ USTABLE FLOATINGROOF Alexander F. Fino, Warren,-Pa., assignor to-Hammond This invention relates generally to storage tanks for liquids and more particularly to tanks for storing oil products wherein there is employed a roof or cover which floats on the liquid stored in. the tanks to rise and fall with the level of such liquid.

In tanks of the type referred to, a space-is present around the periphery of the floating roof andthe tank wall which must be kept closed or sealed at all times during the movement of the roof with the changing level of the liquid on which it floats and, it is accordingly, an object of the present invention to provide in a manner as hereinafter set forth a new and improved roof construction whereby the maintenance of such a sealbetween the outer part of the roof and the wall is effected.

Tanks of the character stated are ofrelatively large diameter and accordingly the inner periphery of the tank wall against which the seal carried by thefloating roof engages is seldom of a true circular form and usually has many other and substantial irregularities. It is accordingly a further object of the invention to provide an improved floating roof structure which will automatically adjust itself to such irregularities was to maintain the desired sealing engagement with the tank wall.

Still another object of the invention is to provide a floating roof structure wherein there are a number of radially shiftable coupled sections with means at the central portion of the roof for controlling the radial movements of the sections as the roofrises and falls and as it passes over irregularities'in the circular contour of the wall so that such sections will maintain desired sealing contact at their outer edges with the tank wall regardless of the variations in the circular contour thereof.

Still another object of t the invention is to provide an adjustable floating roof structure which-will automatically adjust itself to any diameter of the tank in which it is disposed, within reasonable limits.

Still another object of the invention isto provide an adjustable floating roof structure embodying in association with a circular central section a plurality of radially extending sectors having interengaging sealing contact one with the other between adjacent radial edges and having a novel connection at their inner ends with the central section whereby the radial movement of the sectors is caused to take place as the interior diameter of thetank varies or as the sectors pass over irregularities'therein whereby to maintain in constant sliding engagement with the inner surface of the tank a sealing means carried by the outer ends of the sectors.

Still another object of the invention is to provide a floating roof construction of the character above described, whichis formed of a relatively light material such as a suitable plastic which will be unafiected by the liquids in thetank and which has a substantial strength to-maintain its form and position, which embodies'in its construction a material giving it buoyancy suflicienttozprevent its sinking in the liquid on which it is designed to float.

A still further object of the invention is to provide an adjustable floating roof construction which is not only designed in a novel manner to permit the radial movements of the plurality of sectors with respect to a central circular section around which they are disposed so as to automatically adjust itself to variations in the diameter of the tank but which is designed so that such sectors will maintain a sufiicient degree of inclination to efiect the movement of condensate outwardly to the periphery of the roof for drainage through the seal against the shell of the tank.

As this invention maybe embodied in several forms without departing from the spirit or essential characteristics thereof, the present embodiment is therefore illustrative and not restrictive, since the scope of the invention is defined by the appended claims rather than by the description preceding them, and all changes that fall within the metes and bounds of the claims or that form their functional as well as conjointly cooperative equivalents, are therefore intended to be embraced by those claims.

The invention is illustrated in the accompanying drawings wherein one embodiment of the invention has been chosen for illustrating, but not for limiting, purposes.

In the drawings:

Fig. 1 is a vertical sectional viewthrough a conventionally illustrated tank structure shown in perspective and illustrating in perspective therein a floating roof structure constructed in accordance with the present invention in diametrical section, the roof sections being shown adjusted to the tank diameter to have a slight degree of slope;

Fig. 2 is a, view in top plan of the roof structure, a portion of the same being broken away;

Fig. 3 is a top plan view on an enlarged scale of a number of the sectors detached from the central section;

Fig. 4 is a sectional view taken substantially on the line 4-4 of Fig. 3;

Fig. 5 is a sectionalview on a vertical plane diametrically through the central section of the roof, the view being on an enlarged scale;

Fig. 6 is a top plan view on an enlarged scale'of the central section with a portion broken away;

Fig. 7 is a sectional View on an enlarged scale taken substantially on theline 77 of Fig. 2;

Figs. 8, 9 and 10 illustrate diagrammatically the dilferent positions of the roof sectors with relation to varying diameters of the tank wall.

Fig. 11 is a top view of one sector only, with the middle portion broken out, and showing in dotted lines the boundaries of the chambered foam-glass filled section and the thickened end portions through which the slot extends.

Fig. 12 is a section taken substantially on the line l212 of Fig. ll.

Referring now more particularly to the drawings, thenumeral 10 generally designates a storage tank having a cylindricalvertical wall 12 andbottom 14 and in which is illustrated an adjustable floating roof structure generally designated 16 constructed in accordance with an embodiment of the present invention.

The roof structure comprises a central section or memher which is generally designated 18 and this central section embodies a frusto conical central part or wall 2i), ahead plate 21 which is secured to the top of thewall 20 and abottom plate 22 which is secured across the bottom of the frusto conical wall. The head wall and bottom wall may be of approximately the same diameter as illustrated and this diameter is greater than the diameter of the base portion of the trusts-conical wall so that thebottom plate 22 extends slightly beyond the periphery of the bottom of thewall 20 and this bottom wall and the head wall are provided with alignedopenings 23* and 24 respectively for the purpose hereinafter set forth.

The central section as thus described provides a closed u chamber which is filled with a suitable lightweight buoyant material which will have a buoyant effect in petroleum liquids, foam glass being one example of such material which might be employed.

The frusto-conical wall 20 of the central section provides a circular inclined surface orface 27 which functions as a camming surface in association with the hereinafter described sector portions of the roof.

Disposed around thecentral section 18 of the roof structure is a plurality of sector members each of which is generally designated 28. These sector members are preferably molded from a resin material such as polyester resin or any other suitable form of rigid plastic which can be molded and these sectors are molded to provide thetop wall 29 and an underneath chamber or compartment-forming part consisting of abottom wall 30 andconvergent side walls 31 and 32.

Theouter end edge 33 of the top wall of each of thesectors 28 is of a curvature to conform to the curvature of the inside surface of thetank wall 12.

Theinner end edge 34 of each of the sectors is formed on a concave curvature and conforms to the curvature of the frusto-conical wall 20 of the central section with which it contacts when the sector is assembled with the center section in a manner hereinafter described.

Thechamber 35 formed on the underside of thewall 29 of each sector terminates at the inner and outer ends of thesector wall 29 as indicated at 36 and 37, short of the end edges of thewall 29 and theportion 38 of thewall 29 extending beyond the inner end of thechamber 35 is provided with anelongate slot 39 which is directed longitudinally of thewall 29 or radially of the roof structure.

Extending along one side of each of the sectors, as for example along theside 32, referring to Fig. 4, is an outwardly projectingtongue 40. This tongue extends the full length of the sector and where it extends beyond the ends of thechamber 35 thewall 29 is thickened for strength and to carry the flange, as indicated at 40a.

At the opposite side of each sector from thetongue 40 there is provided the longitudinally extendinggroove 41 which is of a size to receive atongue 40 of an adjacent sector. Thegroove 41 terminates at the ends of thechamber 35.

Thechambers 35 of thesectors 28 are also filled with a buoyant material of the character hereinbefore referred to. In the construction of the sectors from the selected plastic, the plastic material is molded around the body of buoyant material which is designated 42 so that there is a firm bond effected between the material and the plastic material of which the sector walls are made.

Theroof sectors 28 are assembled around thecentral section 18 with thetongues 40 engaged within the grooves of adjacent sectors and the curved inner end edges are disposed against the frusto-conical wall 20 of the center section with theslot 39 of each sector in line with and between twoopenings 23 and 24 of the head and bottom walls of the center section and a retaining pin orbolt 43 is passed through thealigned openings 23 and 24 and through theslot 39 of the interposed end of the roof sector as illustrated in Fig. 1. The length of theslots 39 is such as to permit the movement of the inner ends of the sectors to the full extent permitted by the space between thehead wall 21 andbottom wall 22 of the center section so that in the functioning of the adjustable roof as it rises and falls with the changing level of liquid in thetank 10, the sectors may move radially toward and away from the encircling tank wall as required.

For keeping theslots 39 closed, each sector has disposed for sliding movement upon the top thereof over the slot, a cover plate 39a through which the bolt orpin 43 extends with sulficient freedom to permit the plate to slide smoothly thereon. Also the plate is of sufficient length to cover the slot when the pin is in either end of the slot.

In the complete assembly of the center section and the sectors, the overall diameter of the disc thus obtained is materially less than the inside diameter of the tank so that there remains between theouter edges 33 of the sectors and the tank wall 12 a space as indicated at 44 in Fig. 1.

Thespace 44 is maintained closed in all positions of the floating roof in the tank by means of aresilient sealing band 45 secured around the periphery of the roof. This sealing band may be of any desired character and is here shown as being made up of a series ofrubber wipers 46 each of which is secured by stapling as at 47 or in any other suitable manner to the top of thewall 29 of a sector to project radially outwardly therefrom. The radial width of the wipers is such that in any of the positions to which the floating roof may move in the tank, a firm wiping engagement will be maintained between theouter edge 48 and the tank wall. This wiper is, of course, resilient so that it may bend or flex as required to conform to the dilferent irregularities of the tank and to facilitate such bending or flexing, the outer portion of the wiper may be reduced in thickness or tapered off as indicated at 49 in Fig. 7.

The length of the wiper strips is somewhat greater than that of the arcuate edges of the sectors to which they are secured and each strip is secured to the sector to have the extra length thereof extend beyond the grooved side of the sector, as indicated at 46a, in Figs. 1 and 2. When the roof sectors are assembled, each extended end 46a is positioned for sliding movement on the top of theadjacent strip 46. Accordingly, when the roof diameter increases so that the sectors separate any space occurring between the outer ends of the sectors will be kept covered.

In the operation of the roof structure, the adjustment of the center circular section is the key to the automatic functioning of the roof to adjust itself to any tank diameter within reasonable limits. The roof would be designed for a tank of a certain standard diameter with the length of the radial sections long enough that it cannot adjust to its normal displacement without forcing down thecenter circularv section 18. For example, Fig. 8 illustrates the normal displacement of the sectors and if the tank shell becomes smaller in diameter by one or two inches during the course of travel of the roof, the radial sections or sectors will slide upward at their inner ends on thecircular sloping surface 27 of thefrustoconical wall 20 as illustrated diagrammatically in Fig. 9. Additional displacement of the center section will occur but being free for movement, binding cannot occur. Likewise, on descending or downward movement of the inner ends of the sectors, as the tank wall or shell 'becomes larger than the standard neutral diameter, the radial sectors will be forced toward the shell or wall as the roof section tends to level to its proper displacement. This adjustment will take place continuously and automatically for each of the sectors and will tend to seal localized buckles and irregularities in the form of the tank wall.

Fig. 10 illustrates maximum radial displacement where the sectors are substantially horizontal while Fig. 9 illustrates the minimum radial displacement where the sectors may have a slope of approximately 2 /2 degrees while in the neutral position of the sectors shown in Fig. 8, the sectors have a slope of approximately 1 degree.

In automatically adjusting itself to irregularities of the tank wall, the radial movements of the sectors do not have to be simultaneous or in unison.

From the foregoing description it will be readily apparent that there is provided by the present invention a new and novel floating roof structure which will automatically adjust itself to conform to changes in the contour of the tank wall in which the roof is positioned, as the liquid in the tank rises and falls thereby maintaining at all times the desired sealing of thespace 44 between the outer part or periphery of the Wall of the roof and the wall of the tank. I

By forming this floating roof of plastic and buoyant material in the manner illustrated and described, a light weight but very strong and rigid construction is obtained.

Further, by the provision of a floating roof structure formed substantially throughout of plastic or other material of a non-metallic nature, such roof may be easily installed in existing tanks without danger of fire resulting from sparks such as might occur in handling metallic roof structures and metallic objects for installing such structures.

I claim:

1. A floating roof construction for installation in a tank having a vertical cylindrical wall comprising a central section having a downwardly and outwardly extending middle part, a circular head wall upon the top thereof and a circular bottom wall with the latter two being concentric with and of greater diameter than the base of the middle part, while the middle part provides a circular sloping wall, a plurality of sector shaped outer sections in side-'by-side relation around and extending radially from the middle part of the central section with their inner ends between the head and bottom walls while having sliding sealing engagement with the sloping wall, means for retaining the inner ends of the sectors between the head and bottom walls while permitting limited radial movement of the sectors, means forming a sealing coupling between the adjacent sides of the sectors, and yieldable elastic sealing means encircling the roof While joined to the outer ends of the sector sections, wherein said means for retaining the inner ends of the sectors between the head and bottom walls comprises pins extending between the head and bottom walls and passing through radially extending slots in the said inner ends of the sectors.

2. A floating roof construction including a central section and a plurality of sector-shaped members movably secured thereto, each sector member comprising a hollow floatable chamber including a top, bottom and side and end walls, said side and end walls secured to the under face of said top wall inwardly of the terminal ends thereof and converging toward said bottom wall,

I tank wall while being dimensioned to maintain edgewise floatable material completely enclosed in said hollow chamber, flange means formed integral with said top wall in the same plane as said top wall and extending inwardly from the terminal edges of said top wall to a point adjacent the juncture of said side and end walls with the underside of said top wall, said central section being of greater thickness than the sector members and having a downwardly and outwardly sloping peripheral side wall engaging s'aid'innermost flange means of each sector to urge same outwardly, vertically extending rod means secured to said central section, said innermost flange means of each sector being movably secured to said rod means to retain the sectors in position and permit relative horizontal and vertical movement therebetween, and wiper means secured to the outermost flanges of each sector to form a seal between the sector flanges and the side walls of the receptacle in which the floating roof is positioned.

3. A floating roof construction as defined in and by claim 2 wherein said floatable material comprises a lightweight cellular material, and having an external shell of plastic material completely enclosing the cellular material in bonded relationship therewith.

4. In a liquid storage tank having a wall, a roof construction floating on the liquid to rise and fall with changes in the liquid level having a conical buoyant center section, a series of buoyant sector bodies extending radially from the center section and constituting a floating ring around the center section substantially occupying the annular space between the center section and the contact at their inner ends upon the conical face of the center section and thereby assuming a slight downward outward inclination, said sector bodies adjusting themselves to irregularities of thetank wall as the level falls and rises by undergoing corresponding variations of their inclination accompanied by corresponding changes of immersion of the center section with the sector sections shiftable relative to one another and their inner ends moving up and down the conical face of the center section, vertical guide means carried by said center section and etfective'to provide for limited radial as well as upand-down movement of each of the inner ends of respective sector bodies while substantially preventing lateral displacement thereof, said guide means having a bottom flange and a top flange provided upon said center section, and a guide pin extending between said flanges for each sector body and passing through respective radially-extending slots in the inner ends of the sector body.

References Cited in the file of this patent UNITED STATES PATENTS 1,712,321 Afonin May 7, 1929 1,901,874 Horton Mar. 21, 1933 2,006,505 Lentschewsky July 2, 1935 FOREIGN PATENTS 291,618 Great Britain June 7, 1928 832,842 France July 11, 1938

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