US3059806A

US3059806A - Floating roof tank seal

Info

Publication number: US3059806A
Application number: US846011A
Authority: US
Inventors: Ii William E Joor
Original assignee: Individual
Current assignee: Individual
Priority date: 1959-10-12
Filing date: 1959-10-12
Publication date: 1962-10-23
Anticipated expiration: 1979-10-23

Description

Oct. 23, 1962 w, JQQR, 3,059,806

FLOATING ROOF TANK SEAL Filed Oct. 12. 1959 3 Sheets-Sheet 1 Q III!!!" I INVENTOR. Vv/ll/am 5. door, E

ATTORNEY i Oct. 23, 1962 w. E. JOQR, n

FLOATING ROOF TANK SEAL 3 Sheets-Sheet 2 Filed Oct. 12. 1959 INVENTOR. VV////am 5. door ,1?

Oct. 23, 1962 w. E. JOOR, n

' FLOATING ROOF TANK SEAL 3 Sheets-Sheet 3 Filed 001;. 12, 1959 INVENTOR. W////a m 4/00/51? ATTDR/VEV United rates Patent @hfiee 3,059,806 Patented Oct. 23, 196.2

3,059,806 FLOATING ROOF TANK SEAL William E. Joor II, R0. Box 3052, Houston 1, Tex. Filed Oct. 12, 1959, Ser. No. 846,011 2 Claims. (Cl. 220-26) This invention relates to floating roof tanks and particularly to roof seals therefor.

It is necessary in such tanks to provide suflicient clear ance between the roof and the tank Wall to permit free, vertical reciprocation of the roof within the tank. Such clearance is also necessitated by the fact that large tanks cannot be built accurately cylindrical. For instance, the tank wall, in horizontal section, may be slightly elliptical, or may have one or more nodes around the periphery thereof. Such out-of-roundness may be due to locked up stresses set up during field welding of the tank wall or to inaccuracies in the plate contours before assembly, or both. Where volatile liquids are to be stored, this clearance must be provided with an adequate seal which not only does not impede normal roof movements, but which also will accommodate itself to variations in the tank Wall contour both vertically and circumferentially.

Accordingly, it is the main object of the present invention to provide such a floating roof tank seal.

Another object is to provide a seal for floating roof tanks embodying an annular fluid-distending bag and means for supporting the bag in sealing position, which means is located wholly outside the bag in position for ready inspection and so as to avoid corrosion or gumming of the hanger arms or their pivotal attachments due to the weighting and distending liquid in the bag and also contamination of the weighting liquid, as by coatings or lubricants on the arms.

Still another object is to provide an annular, bag-type seal for floating roof tanks in which the sealing bag is supported by outwardly and upwardly inclined hanger arms bridged between the roof and tank and having antifriction means bearing against the tank wall.

These objects and other more detailed objects here after appearing are attained by my novel roof seal structure which comprises, generally, an annular, closed (doughnut shaped) bag of pliable, imperforate material interposed in the space between the edge of the roof and the tank wall. The bag is supported by a plurality of radial, upwardly-inclined hanger arms located above the bag and having anti-friction means at their free ends bearing against the tank wall. Chains or straps depending from the arms are secured to and support the bag. Projecting upwardly from the free ends of the arms are brackets which support a rain shield overlying and closing the clearance space between the edge of the roof and the tank wall.

In the accompanying drawings which illustrate the invention, FIG. 1 is a perspective view of a floating roof tank embodying my novel seal, parts being broken away to illustrate the underlying structure.

FIG. 2 is an enlarged, vertical, transverse section through the sealing structure.

FIG. 3 is an enlarged view of a detail of FIG. 2.

FIG. 4 is a partial vertical, transverse section taken substantially on the line 4-4 of FIG. 2.

FIG. 5 is a partial horizontal section and plan view taken on line 5-5 of FIG. 2.

FIG. 6 is a vertical transverse section illustrating a modified form of seal.

FIG. 7 is a similar view illustrating still another form of seal.

The tank comprises a cylindrical wall 10 open at the top and receiving therein a roof 11 having a generally conical main body and a peripheral pontoon 12. Access stairways are illustrated at 13.

bars 35 extend, intermittently,

Interposed within the space between roof edge plate 14 and the tank wall and extending entirely around the root is an annular, doughnut shaped bag 15 made of pliable, imperforate material such as synthetic rubber coated fabric. As best shown in FIG. 2, this bag material is crimped or overlapped at its inner side, as at 16, where it is sealingly secured to the horizontal flange of an angle bar 17 welded to roof edge plate 14. As shown in FIG. 3, rubber strips 18 are interposed between the fold or bight 16 of the bag and angle 17 and channels 19 laid on top of the fold. The area around strips 18 is suitably sealed, as by a rubber cement material, and the whole assembly secured by bolts 26 and washers 21. A quantity of liquid 22, such as kerosene or other non-freezing material, partially fills bag 15 for weighting and distending the same to cause the outer part or sheet 23 of the bag to bear sealingly against the inner face of the adjacent tank wall. Bag 15 may be formed of a single sheet of material which is first draped around the tank wall, then lifted at its lower edge to form the bottom of the bag. Clamped part 16 may be either a fold or bight of continuous material, or the overlapped ends of separate sheets. A plurality of hanger arms 25 project radially and upwardly from the roof edge sheet 14 at regular intervals therearound and each arm 25 (FIGS. 4 and 5) has

lcross bars

26 and 27 at its opposite extremities. Each lower cross bar 26 is in the form of a hollow tube which receives a shaft 28 which, in turn, is journaled in a pair of angle brackets 29 projecting from the roof edge sheet above bag attaching flange 17. The upper cross bar 27 of each arm is, similarly, of tubular construction and receives a shaft 30 which, at each end, mounts a roller 31. The; rollers 31 bear against the inner face of the tank Wall and form anti-friction means between the hanger arms and the tank wall.

Depending from each upper hanger arm cross bar 27, at opposite sides of arm 25 and secured thereto by collars 32a, are a pair of chains 32 which, at their lower extremities, are secured by means of lugs 33 and bolts 34 to bars 35 secured to the upper extremity of bag 15. Pairs of entirely around bag 15, the upper extremities of

sheets

23 and 36 forming bag 15 being clamped between the pairs of bars 35 by means of bolts 37. Preferably, shafts 30 are disaligned vertically with respect to the center of gravity of bag 15, in other words, closer to the tank wall so that the force of gravity tends to cause the bag to follow irregularities in the tank wall so as to bear sealingly thereagainst.

Projecting upwardly from each upper cross bar 27 is a pair of brackets 38, secured to chain supporting collars 32a, having acutely angled flanges 39 to which are secured an upwardly-angled secondary sealing member 40, bear-- ing at its upper extremity against the tank wall, and a downwardly-extending rain shield sheet 41 having strengthening corrugations 42. Rain shield 41 rests at its lower extremity upon the top of pontoon 12 so as to overlie and protect the clearance space between the roof edge plate 14 and the tank wall.

In operation, it is obvious that as the roof rises and falls with the increase and decrease of product liquid 4-3 in the tank, liquid weighted and distended bag 15 is, likewise, carried upward by hanger arms 25 causing outer sheet 23 of the bag to slide along the tank wall. Because of anti-friction rollers 31, hanger arms 25 move smoothly along the tank Wall and bag 15, because of its pliable nature, can yield, as required, to conform with irregularities in the tank wall and thereby maintain a good seal. Preferably, the roof and seal are designed so that the lower part of bag 15 depends below the surface of the product liquid, thus preventing the formation of a gas pocket above the body of product liquid.

FIG. 6 shows a modification in which annular closed bag 46, partially filled with distending fluid 47, slidably engages both the roof edge sheet 48 and the inner face of the tank wall 49. Radially and upwardly inclined support arms 50, disposed at regular intervals about the roof, are pivotally attached to the roof, as in the previous form, by means of lugs 51. Rollers 52 at the upper extremities of arms 50, form anti-friction bearings between the arms and the tank wall. The upper portion of the bag is clamped between pairs of circumferential bars 53 and these are secured to and supported by straps 54- depending from hanger arms 50. Other straps 55 are secured to pairs of circumferential bars 56 between which are clamped the lower edges of the bag forming pliable sheets. As in the first form, bag 46 may be formed by a single sheet with its meeting edges cemented or merely clamped between pairs of bars 53 or 56, or of two separate sheets of material with their meeting edges overlapped, clamped and sealed between both sets of clamping bars. Straps 55, at their lower extremities, are pivotally secured to bell cranks 57 which are pivotally attached to the bottom of roof pontoon 58 by means of lugs 59. Weights 6% at the inner ends of bell cranks 57 maintain anti-friction rollers 61 at the outer ends of these bell cranks in engagement with the tank wall. Accordingly, in this form, sealing bag 46 with its distending fluid, liquid or gaseous, is maintained properly positioned by opposing pivoted arms 50 and 57.

In the third modification shown in FIG. 7, annular, closed sealing bag 64, is supported from pivoted hanger arms 65 by means of chains 66. Clamping bars 67 at the top of bag 64 are positioned slightly inwardly of the brackets 68 which attach the upper ends of the chains to the hanger arms so that the force of gravity tends to maintain sealing bag 64 bearing firmly against the tank wall, irrespective of irregularities therein. A protector sheet 69 extends from clamping bars 67 to angular bracket 76 projecting from tank roof edge sheet 71. A second bag 72 rests against the upper, inner surface of bag 64. Bag 72 has a filling of weighty material, solid as sand, or liquid, which being also eccentrically as well as swingably supported, tends to additionally urge outer bag 64- into sealing engagement with the tank wall. A rain shield 73 overlies the clearance space between the roof and tank wall, as in the previous forms.

The novel, annular-bag-type, floating roof tank seal has a number of important advantages over previous practice. The exposed positioning of the hanger arms fa cilitates inspection and repair without the necessity of draining the tank, since all supporting parts are readily accessible. The seal and its supports have fewer more rugged parts than previous seals and may be more easily and less expensively installed in the field and are less subject to mechanical trouble, thus requiring reduced maintenance. The hanger arms may be used to ground the roof through the tank wall. Since there is no vapor space above the product, the parts are less subject to corrosion. The seal works better and is less subject to wear when used in riveted tanks. Finally, the seal insures the application of substantially equal sealing pressure all around irrespective of tank wall irregularities and the sealing pressure increases in case of an abnormal load on the roof.

The invention may be modified in various respects as will occur to those skilled in the art and the exclusive use of all modifications as come within the scope of the appended claims is contemplated.

I claim:

1. In a floating roof tank, a flexible seal between the tank wall and roof comprising a bag of pliable material having a free hanging, bellied bottom and side flaps joined at their upper extremities, reinforcing bar means secured to said joined extremities, fluid distending material in said bag, support arms projecting from said roof above said bag and bearing against said wall, and tension members pivotally secured to and extending downwardly and inwardly from the outer portions of said arms and secured to said bar means for suspending said bag while biasing the same against said tank wall.

2. A floating roof tank seal comprising an annular closed tube of imperforate material interposed in the space between the edge of the roof and the tank wall and surrounding the roof, fluid material in said tube for distending the same against the roof and tank wall, rigid bar means secured to the upper portion of said tube, a plurality of arms pivotally secured to the edge of the roof and extending radially upwardly therefrom above said tube and bearing against the tank wall, suspension elements depending from said arms and secured to said bar means for supporting said tube, and weighted means eccentrically and swingably supported by said bar means and bearing against the inner face of said tube for urging the same outwardly.

References Cited in the file of this patent UNITED STATES PATENTS Re. 22,169 Hammeren Sept. 1, 1942, 2,066,292 Kuehn Dec. 29, 1936 2,314,805 Wiggins Mar. 23, 1943 2,471,404 BOberg Mar. 31, 1949 2,531,424 Goldsby et al. Nov. 28, 1950 2,735,573 Fino Feb. 21, 1956 2,968,420 Harris et al I an. 17, 1961 FOREIGN PATENTS 540,391 Germany Dec. 15, 1931