US3255914A

US3255914A - Seal

Info

Publication number: US3255914A
Application number: US290805A
Authority: US
Inventors: James W Nelson
Original assignee: Union Tank Car Co
Current assignee: Union Tank Car Co
Priority date: 1963-06-26
Filing date: 1963-06-26
Publication date: 1966-06-14
Anticipated expiration: 1983-06-14
Also published as: BE649453A; GB1063165A

Description

June 14, 1966 J. W. NELSON i SEAL 2 Sheets-Sheet 1 Filed June 26. 1963 June 14, 1966 J. w. NELSON SEAL 2 Sheets-Sheet 2 Filed June 26. 1963 INVENTOR. .v//w Me/fwg, BY

United States Patent O Filed June 26, 1963, Ser. No. 290,805 1 Claim. (Cl. 220-26) This invention relates in general to floating roof storage tanks of the type generally used in storing volatile liquids such as petroleum products and the like. It deals more particularly with a sealing arrangement and method of moltlnting a flexible tubular seal in afloating roof storage tan It is an object of the present invention to provide an improved sealing arrangement of the flexible tubular seal type.

.It is another object t-o provide a sealing arrangement including a new and improved mounting assembly for a Ilexible tubular seal.

It is still another object to provide a mounting assembly which 4facilitates easy installation `and removal of the flexible tubular seal from the top of a floating roof with a'minimum of elfort.

It is yet another object to provide a mounting assembly of the aforedescribed character which nevertheless prevents the flexible tubular seal from being dragged up by tank wall friction and possibly damaged through creasing, folding, an-d overlapping, when the floating roof descends in the storage tank.

It is a further object to provide a mounting assembly for a flexible tubular seal which readily permits the floating roof to descend substantially to the floor of the storage tank as the liquid level is lowered without damage to the mounting assembly and without an air space forming over the stored liquid.

It is still a further object to lprovide a new and irnprove-d method of mounting a flexible tubular seal in a floating roof storage tank.

The foregoing and other objects are realized in accordance with the present invention by providing a seal- `ing arrangement including a mounting assembly and a method for mounting a flexible tubular seal on the oating roof of a floating roof storage tank. The mounting as- Isembly is applicable to virtually all types of uid and Afoam seals. Itis particularly adaptable, however, to partially lilled seals of the type illustrated generally in the Harris et al. Patent No. 2,968,420, for example.

Y The mounting assembly and method facilitate easily and r quickly mounting a flexible tubular seal between the tank wall and the floating roof of a storage tank while stan-ding on the roof with the roof in place in the tank. Correspondingly, the tubular seal can'easily be removed from the top of the'iloating roof. Nevertheless, the seal is secured, while in operative relationship, to both the upper land lower peripheries of the roof and consequently the seal is restrained and cannot crease, fold-up, and overl-ap so as to become -damaged during movement of the roof downwardly, for example. Furthermore, the mounting assembly does not protrude any substantial distance below the level of the floating roof and, accordingly, the roof can readily descend virtually to the oor of the tank.

Several forms of the invention are illustrated. Generally speaking, each is applicable to virtually all seals of this general type. Nevertheless, in most instances it is preferable to use one type or another with a specific seal type. The invention, both as to its organization and method of operation, taken with further objects and advantages thereof, will best be understood by reference to the accompanying drawings in which:

FIGURE 1 is a perspective view, with parts broken away, of a floating roof storage tank incorporating a sealing arrangement embodying features of the present lnvention;

FIGURE 2 is an enlarged sectional view of one form of sealing arrangement embodying features of the present invention, utilizing a liquid type seal;

FIGURE .3 is a further enlarged sectional view taken hrough the` seal itself, in nonoperational cylindrical orm;

FIGURE 4 is an elevational view of the T-bar component of the one form of sealing arrangement embodying features of the present invention;

FIGURE 5 is an enlarged sectional view of another form of sealing arrangement embodying features of the present invention, utilizing a liquid type seal;

FIGURE 6 is a perspective view of a T-hook component of the other form of sealing arrangement; and

FIGURE 7 is an enlarged sectional view of the other form of sealing arrangement adapted to a gas type seal.

Referring now to the drawings, and particularly to FIGURE' 1, a oating roof tank of the type used in the petroleum industry to store volatiile petroleum products and the like is seen generally at 10. A roof 11 floats on the surface of a stored liquid 12 within the tank 10, substantially eliminating any space, between the liquid and the roof, in which vapors might accumulate. The tan-k 10 is normally cylindrical in shape `and relatively large in diameter; an exemplary tank might be in diameter, for example. v

The roof 11 is circular, of course, and is so constructed rthat it has a diameter slightly less than the diameter of `between six and twelve inches or more, is necessary to permit the roof 11 to ride up and down within the tank 10 without interference between the r-oof 11 and the wall 15 of the tank. Y

To prevent the escape of vapors from the stored liquid 12 through the space 16 to the atmosphere, a flexible sealing arrangement 18 is mounted on the peripheral wall 7 of the roof 11 between the roof `and the tank wall 15. The sealing arrangement 18 embodies features of one form of the present invention and comprises a toroidal seal 20 and .a mounting 21 securing the seal 20 to the periphery of the floating roof 11.

The toroidal seal 20 comprises a flexible, collapsible tube 23 which, in this case, is partially filled with a weighing liquid 24. The weighing liquid might be kerosene or fuel oil, or even water in non-freezing areas, and is utilized to provide hydrostatic pressure for expanding the tube into sealing relationship with the roof 11 and the tank 10, of course. The seal 20 flexibly ills the space 16 between the tank 15 and the roof 11 in a generally well-known manner, 4as illustrated in the aforementioned Harris et al. patent, and conforms to the configuration of the peripheral wall 17 of the roof 11 as well as to the internal surface of the tank wall 15. The mounting assembly 21 holds the toroidal seal 20 in the annular space 16 and prevents the tube 23 from creasing, folding, and overlapping whereby it might become darnaged as the roof 11 moves up and down in the tank 10.

Referring to FIGURE 3, the tube 23 is illustrated in its free form in cross section. The tube 23 is preferably fabricated from one piece of a syntheticiabrie such as nylon or the like, and is coated with rubber, for example, to make it impervious to the weighting liquid 24 and the stored liquid 12. Approximately 120 displaced from eachother around the cross sectional circumference of the tube 23 are an annular upper tab 30 and an annular lower tab 31. In practice, the upper vtab 30 is preferably defined by the fabric seam, as will be noticed, while the lower tab 31 might be a separate piece of material seWed to the fabric in tab form. The

tabs

30 and 31 extend entirely around the annular tube 23, of course, and provide the handles by which the mounting assembly 21 secures the toroidal seal 21 to the peripheral wall 17 of the floating roof 11. Note that the tube 23 is constructed with a double fabric thickness at its outermost side 32 to accommodate abasion wear to which the tube 23V is subjected as the roof 11 rides up and down in the tank 10, when stored liquid 12 is introduced or removed from the tank, for example. Note also that the tube 23 has a single thickness at its innermost side 33 since this side is not normally subjected to any substantial abrasion wear.

Referringnow to FIGURES 2 and 4, the mounting assembly 21 which secures the toroidal seal 20 to the periphery of the roof 11 includes a spaced series of T-bars 40 (only one of which is shown). The cross-piece 41 of each bar 40 is secured to the lower tab 31 of the seal 20 by three conventional bolts 42. The depending lleg 43 of each bar 40 has a vertically elongated aperture 44 formed therein which is adapted to be slipped over a correspondingly positioned bumper bar 45 secured to the bottom of the floating roof 11 by welding or the like. Each bumper bar 45 has a notch 46 formed in its lower edge into which the base edge 47 of the aperture 44 in the depending leg 43 is drawn when it is slipped over the bar. The notch 46 holds the leg 43 in a prescribed position, of course.

The bumper bars 45 serve -to prevent the roof 11 from crushing the toroidal seal 20 as the roof is -moved around on the surface of the stored liquid 12 by high winds, for example. Such bumper bars 45 are normally only necessary in open top floating roof tanks, however, where the roof is subject to such forces. As will hereinafter be pointed out, where a closed top floating roof tank is utilized, a slightly modified mounting assembly construction is often used.

The toroidal seal 20 is supported from the roof 11 by its upper tab 30 which is secured to a flange 5G provided around the upper edge of the peripheral wall 17 of the iloating roof 11. A spaced series of conventional bolt clamps 51 secure the upper tab 30 to the flange 50 around its circumference. As will be noted, the innermost side 33 of the toroidal seal 20 is stretched out between the bumper bar 45 and the flange 51.

To support the liquid filled toroidal seal 20 in such a manner that a substantial portion of its outer side 32 is forced against the tank wall 15, a continuous angle ring .55 is provided beneath the seal 20, supported from the annular wall 17 of the roof 11 by a spaced series of bar elements 56. The use of such an angle ring 55 is par- ;ticularly desirable where the average gap between the V'roof 11 and the wall 15 is relatively large, in excess of I8-l0 inches for example. In such case,y an unsupported liquid lled tube 23 would tend to droop too much and perhaps seal ineffectively. The bar elements 56 are preferably welded to the peripheral wall 17 of the roof 11 Iand also to the continuous angular ring 55.

The toroidal seal 20 can be mounted in place and removed from the annular space 16 by personnel working solely from the top of the roof 11, as has been pointed out. Accordingly, there is no necessity for removing the roof 11 or draining all of the stored liquid 12 from the tank 10, for example, to mount or remove the seal 20.

VTo mount the toroidal seal 20 in the space 16, the flexible tube 23, empty of any liquid 24, is lowered into the annular space from the top of the roof 11 until the 1depending legs 43 o f the lbars 40 are in position to slip over corresponding bumper bars 45, via the apertures 44. With each leg 43 hooked into a corresponding notch 46 in a bumper bar 45, the empty flexible tube 23 is pulled upwardly by its upper tab 30 and secured to the flange 50 around the periphery of the roof 11. Once secured in this manner, a Apredetermined amount of weighting liquid 24 is poured through openings (not shown) in the upper seam defining the tab 30; openings left unsealed for this specific purpose. The weighting liquid 24 urges the seal 20 into sealing relationship with the peripheral wall 17 of the roof 11 and the wall 15 of the tank 10.

As the roof 11 moves up and down in the tank 10 on the surface of the stored liquid 12, the outermost side 32 of the toroidal seal 20 slides on the tank wall 15, of course. Since the toroidal 20 is only partially filled with liquid 24, it is quite flexible and the position of the seal 20 changes somewhat as the roof 11 moves up after once moving down, and vice versa. The mounting assembly 21 prevents the seal 20 from being drawn any substantial distance upwardly by friction, however, as the tank roof 11 moves down, so that the tube 23 cannot be creased, folded, overlapped and possibly damaged.

Nevertheless, if it is desirable to remove the sealing arrangement 17 from the annular space 16, it is only necessary to remove the liquid 24 from the tube 23, preferably in the manner in which it was introduced. The bolt clamps S1 are then removed from the upper `tab 30 of the seal 20 and the seal lowered slightly to a point where the depending legs 43 of the T-bars 40 can be pulled off the bumper bars 45. The entire sealing arrangement 17 is then pulled out of the annular space 16 for repair or replacement or the like.

Referring now to FIGURES 5 and 6, another form of sealing arrangement embodying features of the present invention is illustrated generally at 118. The sealing arrangement 118 includes the aforedescribed toroidal seal 20 and a mounting assembly 121 securing the seal 20 to' the periphery of the floating roof 11. The mounting assembly 121 holds the toroidal seal 20 in the annular space 16 and prevents the ltube 23 from creasing, folding, and overlapping, whereby it might become damaged as the roof 11 moves up and down in the tank 10.

The tube 23 is identical to that described in relation to the rst form of the present invention and, accordingly, is not described again n detail. Suflice it to say that it has an annular upper tab 30 and an annular lower tab 31, as well as a double thickness outermost side 32 and a single thickness innermost side 33.

The mounting assembly 121, which secures the toroidal seal 20 to the periphery of the roof 11, includes a spaced series of T-hooks (only one of which is shown). A cross piece 141 of each T-hook 140 is formed by an angle iron including a horizontal flange 141a and a vertical flange 141b. A series of apertures 141e are provided in the vertical flange for receiving three conven- -tional bolts 142 which secure the T-hook 140 to the lower tab 31 of the seal 20.

To support the liquid filled toroidal seal 20 in sucha manner that a substantial portion of its outer surface 32 is forced against the tank wall 15, the bolts 142 are extended to such a length that they force the angle iron 141 a substantial distance from the annular wall 17 of the roof 11. Accordingly, the partially filled liquid seal 20, which rests on the horizontal flange 141a of the angle iron 141, is urged outwardly against the tank wall 15. This construction is preferably utilized where the average gap between the roof 11 and the wall 15 is only in the neighborhood of six to ten inches or the like and an angle ring support is not required.

The depending leg 143 of eachT-hook 140 is formed by a metal rod and has an upturned hook 144 formed at its lower end. The leg 143 is preferably welded to the vertical flange 141b of each cross-piece 141. As seen in FIGURE 5, a hook 144 is adapted to be slipped under a correspondingly positioned bumper bar 145 secured to the bottom of the iloating roof 11 by welding or the like.

The toroidal seal 2() is supported from the roof 11 by its upper tab 3i) which is secured to a flange 150 provided around the upper edge of the peripheral wall 17 of the floating roof 11. A spaced series of conventional bolt clamps 151 secure the upper tab 30 to the flange 150 around its circumference.

The sealing arrangement 118 facilitates mounting the toroidal seal 20 in place or removing it from the annular space 16 by personnel working solely from the top of the roof 11 also, of course. To mount the seal 20' an empty tube 23 is lowered into the annular space from the top of the roof 11 until the hook 144 on the depending leg 143 of the T-hook 140 hooks under a corresponding bumper bar 145. The empty tube 23 is then pulled upwardly and its upper tab 30 secured to the flange 150 around the periphery of the roof 11. Weighting liquid 24 is then poured through openings (not shown) in the upper seam dening the tab 30. 'The seal 20 is removed by a mere reversal of this procedure, of course.

The same sealing arrangement 118 can be modified slightly, as seen in FIGURE 7, to define a variation on the second form of the present invention described immediately above. ln the instance the sealing arrangement 118 is shown to 'be inclusive of a partially filled gas type seal 20 and a mounting assembly 121. Here it will beseen that the annular wall 17 of the roof 11 is extended downwardly to form a lip 117. The hook 144 on the leg 143 of the T-hook 140 is ybent 90 from a position illustrated in FIGURE 6 and, accordingly, readily hooks under the lip 117.

This construction is frequently utilized with a closed top floating roof tank. In such tank-s ybumper bars are not ordinarily provided on the lloating roof since violent movements of the roof under the influence of the wind, for example, are not encountered. Installation and removal of this sealing arrangement 118 would be substantially identical to that described in relation to the sealing arrangement 118 incorporating a liquid filled seal 20, of course.

Although the present invention has been described primarily in terms of fluid-filled seals, including Vboth gas and liquid it finds easy adaptation, as would be expected with various other forms of seals. For example, it might be used lwith a seal incorporating a resilient foam medium for expanding the flexible tube 23.

While the several embodiments described herein are at present considered to be preferred, it is understood that various modifications and improvements may be made In 4a floating roof storage tank, a seal arrangement for providing an effective seal `between the periphery of floating roof and the tank shell, comprising: a tlexible tubular seal in the space between said floating roof and said shell,

an upper attachment tab and a lower attachment ta-b formed on -said tube and extending around the inner circumference of said tube in vertically spaced relationship, and mounting means mounting said seal on the periphery of said iloa-ting roof, said mounting means including a plurality of individual T-shaped anchor hooks secured to said lower attachment tab in spaced relationship around -said tubular seal, each of said hooks including a crosspiece in the form of an yangle member -hav-ing a depending vertical flange secured to said lower tab andan outwardly extending horizontal flange underlying said seal, a spaced plurality of pin members extending through said depending flange toward said roof periphery, said pin members vbeing elongated and labutting said roof periphery to force the lower portion of said seal substantially outwardly against said shell and define a substantial space between said depending flange and said roof periphery, each of said hooks further including a leg member depending from a corresponding cross piece, each leg mem- `ber having hooking means on its lower end removably hooked under complementary means on the lower periphery of said roof, and clamping means securing said upper attachment tab to the upper periphery of the roof.

References Cited by the Examiner UNITED STATES PATENTS 648,355 4/1900 Doolittle 248--304 X 2,696,930 12/ 1954 Moyer 220-26 2,968,420 1/1961 Harris et al. 220-26 2,981,436 4/1961 Fino et al. 220-26 3,116,850 1/1964 Anderson et al. 220-26 3,154,213 10/1964 Ulm 220-26 FOREIGN PATENTS 226,959 10/ 1957 Australia.

THERON E. CONDON, Primary Examiner.

R. A. JENSEN, R. H. SCHWARTZ,

Assistant Examiners.