US3565279A

US3565279A - Floating roof tank seal means

Info

Publication number: US3565279A
Application number: US771588A
Authority: US
Inventors: William E Joor
Original assignee: US Industries Inc
Current assignee: US Industries Inc
Priority date: 1968-10-29
Filing date: 1968-10-29
Publication date: 1971-02-23
Anticipated expiration: 1988-02-23
Also published as: FR2021767A1; DE1902313A1; GB1229752A

Abstract

A seal for a floating roof tank comprising a multiplicity of independent shoes arranged circumferentially about the tank shell and supported and biased against the shell by spring straps secured to the roof and extending therefrom radially outwardly and upwardly and downwardly therefrom and pivotally secured to the upper portions of the shoes. Flexible seal curtain means traverse the space between the upper portions of the shoes and the roof. The shoes, preferably, embody resilient, relatively thin pads in flexible envelopes which bear against the tank shell to accommodate irregularities therein.

Description

United States Patent 2,737,310 3/1956 2,803,371 8/1957 Edens..................

William E. Joor, ll Houston, Tex.

\/)) SSS 666 BB 000 222 222 u m M "E m N uunA a J .m .m kgG gcgl. .l i WLWR O 457 666 999 111 ll, 56. 05 34 955 002 333 Q n I 8 in 11 8 d 93 $22M 7 e 7OFU 0 6 Ce n Mrm ts D S AFPA 1. .1.1 253 2247 [ill [72] Inventor 224,556 11/1962 Austria......................... 220/26(S) Primary ExaminerDonald F. Norton Assistant Examiner-James R. Garrett [54] FLOATING ROOF TANK SEAL MEANS Attorneys-Bertram H. Mann, Frank B. Pugsley, James G.

3 Claims, 10 Drawing Figs. Ulmer, Delmar L. Sroufe and Robert A. White [52] ABSTRACT: A seal for a floating roof tank comprising a mu]- tiplicity of independent shoes arranged circumferentially about the tank shell and supported and biased against the shell by spring straps secured to the roof and extending therefrom radially outwardly and upwardly and downwardly therefrom and pivotally secured to the upper portions of the shoes. Flexible seal curtain means traverse the space between the upper portions of the shoes and the roof. The shoes, preferably, embody resilient, relatively thin pads in flexible envelopes which bear against the tank shell to accommodate irregularities therein.

B65d 87/18 220/26, 26 (S) 220/265UX 220/26(S)X 220/26(S) 220/26(S) 220/26(S) [51] Int. [50] Field [56] References Cited UNITED STATES PATENTS 1,819,401 8/1931 Bailey........................... 1,900,904 3/ 1933 Berger.. 1,913,643 6/1933 Smith 2,478,422 8/1949 Plummer..

2,576,136 11/1951 Moyer..................

PATENTED FEB23 I97! SHEET 1 OF 5 VV////am i c/oar, I

INVEN'IOR.

ATTOR/Vfy PATENIEDFEB2319I| 3565279 sum 5 [1F 5 ATTORNEY FLOATING ROOF TANK SEAL MEANS FIELD OF THE INVENTION This invention relates to seals for floating roof tanks and consists particularly in novel means forl supporting and outwardly biasing the seal shoes and in constructing the shoes in a more efficient manner than heretofore.

SUMMARY OF THE INVENTION An object of the present invention is to provide novel efficient and rugged support and biasing means for the seal shoes.

Another object is to provide seal shoe means embodying a multiplicity of independent shoes each consisting of rigid backing and a resilient facing comprising packing of cellular or other resilient material maintained in a fluidtight and abrasive-resistant envelope.

In all forms of the present invention, a multiplicity of independent seal shoes are supported and biased against the inner face of the tank shell by spring strap members secured to the periphery of the roof and extending radially outwardly and upwardly and downwardly therefrom and pivotally secured to the upper portions of the shoes. Seal curtains extend across the annular clearance space between the upper portions of the shoes and the top of the roof. In some cases the independent shoes embody relatively thin packings of expanded or other cellular resilient material within an envelope of flexible sheeting for hearing against the tank shell face and for accommodating irregularities therein.

BRIEF DESCRIPTION OF DRAWINGS In the accompanying drawings:

FIG. 1 is a perspective view showing a portion of a floatin roof tank and seal means embodying an exemplary form of the invention, portions being broken away and sectioned.

FIG. 1a is an elevation view showing part of the inside of the tank wall and a modified seal.

FIG. 2 is an enlarged detail vertical transverse section taken substantially on line 2-2 of FIG. 1.

FIG. 3 is a vertical transverse radial section taken on line DESCRIPTION OF THE PREFERRED EMBODIMENT In FIG. I there is shown a large circular tank shell 12 having a wind girder l3 projecting outwardly adjacent the upper edge thereof. A floating roof including a peripheral pontoon portion 14 and an intermediate pan portion 15 is loosely received within the tank for floating on the liquid therein. A support column is shown at 16 to limit approach of the roof to tank floor 17.

Seal shoe structure, generally designated 18, extends entirely around the inner face of shell 12 abreast peripheral wall 19 of the roof. This seal shoe consists of an envelope 20 of flexible, abrasive-resistant, fluidtight sheeting, as nylon cloth, impregnated with polyurethane. The envelope may be continuous around the tank and encloses cellular resilient material 21 which, likewise, may be continuous. Material 21 may be expanded polyurethane foam or the like. Extending along the inner upper edge of the shoe envelope are a plurality of thin but

rigid strap bars

23, 24, etc., spaced at their ends, as at 25,

to" permit individual working of the bars. These bars are secured to the upper edge of the resilient shoe material by means of

bolts

26, 27, and 28. Bridging the end gaps between adjacent bars, as 23 and 24, are spring straps, as 29, of double U configuration, as shown in FIG. 5, with end parts secured to the bars by means of the bolts 26.

Shoe structure 18 is supported and outwardly biased by means of generally vertically disposed spring strap members, as at 30, each having a vertical inner leg 31 rigidly secured to peripheral roof wall 19 by meansof bolts or rivets 32, and a radially outwardly and upwardly inclined outer leg 33 connected to inner leg 31 by means of a resilient loop 34. Each outer leg 33 (FIG. 8) has a curved, upper extremity 35 with an aperture loosely received upon one of the bolts 28 and between an inner plate 37 and an outer nut 38 thereon. Accordingly, the attachment of support leg 33 to the upper portion of the shoe structure may pivot or rock as the shoe structure is distorted radially due to irregularities in the tank shell face.

Pairs of preferably metal straps 40 and 41 are pivotally supported by and depend from thebolts 27 projecting inwardly from reinforcing

bars

23 and 24. These straps depend along the inner face of shoe structure 18 and are secured at their lower extremities to a weighted'crossbar 45 which extends through a loop 46 formed at the lower edge of sheeting envelope 20. Due to the reduced thickness of the upper edge portion 47 of the shoe structure and the inward disposition of weight bar 45, this bar acts eccentrically in the mannerof a pendulum to bias the shoe structure along its entire depth against the inner face of the tank shell.

The form in FIGS. 1a, 3, 4, and 5 embodies a plurality of independent shoe members, as at 50 and 51. Each shoe member comprises a thin

metal backing plate

52 or 53 and a sheet of fluidtight,

flexible material

54 or 55* with top edges secured to the plates by bolts 56 and bottom edges folded upon themselves as at 57 to form a flap 58 inserted between backing plate 52 and padding 66 and secured to the backing plate by

bolts

59 and 60. Sheet attaching bolts 56 at the upper edge of the backing plate also secure thereto the upper edge of a flexible seal curtain 62 which traverses the clearance between peripheral wall 63 of the roof and the upper edge portions of the shoe members-The curtain is secured to an angle bar 64 at the upper comer of the roof by means of bolts 65. Flexible sheeting 54, together with backing plate 52 of each shoe struc' ture, forms a fluidtight envelope which is internally packed with a suitable resilient or cellular material 66, such as expanded polyurethane foam or the like.

Each shoe member is supported and biased against the inner face of tank shell '67 by means of one or more circumferentially spaced, vertically-disposed leaf or strap springs 68 intermediately secured to roof peripheral wall 63 by boltsor rivets 69. The upper part of each spring strap member extends radially outwardly and upwardly and downwardly from the roof and is pivotally or rockingly secured to the upper edge portion of one of the shoe members, in the same manner as shown in FIG. 8, by means of a stud 70 loosely receiving the curved extremity 71 of the spring member which is secured in position by a nut 72. The lower portion of each spring strap member extends radially outwardly and downwardly from the roof and has a curved, lower extremity 73 slidably bearing against the lower portion of the shoe member, the spring strap cooperating with the rigid backing plate 52 to bias the resilient outer surface of the shoe member against the tank shell with envelope sheeting 54 in rubbing contact therewith.

In an exemplary form of standard seal according to this form of the invention, each

shoe member

50, 51 comprises a polyurethane foam pad of approximately l /zinches thickness and is approximately 8 feet in circumferential dimension and 2 feet 4 inches in height. Since these shoes will be used in tanks varying widely in diameter--for instance, from 40 to 250 feetshoes of alternative lengths will be provided for use with assemblies of standard shoes to complete encirclement of the tank. FIG. 5 illustrates in section a joint between abutting longitudinal edges of a pair of

adjacent shoe members

50 and 51. A piece of flexible envelope fabric 75 is inserted between polyurethane packing 66 and the inner face of backing plate 52 and is secured thereto by bolts, as at 76. The outer edge of piece 75 overlies and is secured by bolts 77a to the corresponding edge of envelope sheeting 54, and the two pieces of sheeting are feathered as shown to form an inclined edge 78. The flexible envelope sheeting 55 of the adjacent shoe member 51 is similarly secured by bolts, as at 79, to the edge of a sheeting strip 80 which is inserted between polyurethane packing 54a and backing plate 53, the feathering of this part being complementary to the feathered part formed between

sheeting pieces

54 and 75 of the adjacent shoe member to form an inclined edge 81 which abuts edge 78.

Backing plates

52 and 53 may overlap at their juncture, as at 82, and the assembly thereof is resiliently maintained by a spring strip 83 of double-U configuration which is secured to the shoe members by previously-mentioned

bolts

76 and 77. In the assembly, a substantially fluidtight joint is provided between the abutting shoe members, yet these members including the backing plate portions thereof are free to work to accommodate irregularities in the face of the tank shell.

FIGS. 6 and 7 show a modified form of shoe supported and biased by vertically disposed spring 'strap members 85 of generally bow-shaped configuration, as in the previous form. Each of the independent shoes, however, is formed of a relatively thin metal plate as 86 or 91 provided along its upper and lower edges with inwardly

inclined lips

87 and 88 which enable the shoe to ride over irregularities in the inner face of the tank shell 89. FIG. 9 is a detail horizontal cross section illustrating a joint between adjacent shoe plates, as 86 and 91, and showing a spring strap 92 of double-U configuration as in FIG. 5, secured to the shoe plates by bolts 93. The edge of seal curtain 94 is secured to the top

edges'of shoe plates

86, 91, etc., by bolts 95 and pressure plates 96. Preferably, at least a pair of the vertical strap springs 85 may be utilized to support and bias each shoe, but this number will depend upon the circumferential expanse of the shoe, which may be similar to that of the shoes in FIGS. 3, 4, and 5.

Various forms and features may be modified as will occur to those skilled in the art, and the exclusive use is contemplated of all modifications as will occur to those skilled in the art and coming within the scope of the appended claims.

Iclaim:

1. In a tank having a tank shell and a floating roof therein with clearance space therebetween, seal means in said space comprising a plurality of shoes arranged circumferentially about and with faces sealingly and slidably abutting the inner face of said shell, pliable sealing means extending continuously around said space and traversing the same radially between the upper portions of said shoes and said roof, additional sealing means nonrigidly connecting the adjacent ends of said shoes, and vertically disposed, generally bow-shaped spring straps with their center portions secured to the periphery of said roof and extending radially outwardly and upwardly and downwardly therefrom, the upper portions of said straps being rockingly secured to said shoes adjacent said upper portions thereof and beneath said pliable sealing means and the lower portions of said straps slidably abutting the inner faces of said shoes for resiliently supporting said shoes and said sealing means relative to said roof and biasing sa d shoes against the inner face of said tank shell.

2. In a tank shell having a floating roof therein with clearance space therebetween, seal means in said space comprising a plurality of shoes arranged circumferentially about and with faces sealingly and slidably abutting the inner face of said shell, pliable sealing means extending continuously around said space and traversing the same radially between the upper portions of said shoes and said roof, additional sealing means nonrigidly connecting the adjacent ends of said shoes, and vertically disposed spring straps secured to the periphery of said roof and extending radially outwardly and upwardly therefrom and pivotally secured to said shoes adjacent said upper portions thereof and beneath said pliable sealing means for resiliently supporting said shoes and said sealing means relative to said roof and biasing said shoes against the inner face of said tank shell, each of said shoes comprising a form-sustaining backing plate, a sheet of pliable, fluidtight material sealingly secured at its edges to the outer face of said plate for bearing against the inner face of said tank shell, and a packing of resilient material between said plate and said sheet for accommodating irregularities in the shell face, said sheet of material forming an envelope with said backing plate, at least the lower edge portions of said envelope being sealed to prevent access of tank liquid to the packing within said envelope, the adjacent side edges of said pliable material and said packing being feathered to respectively overlie and underlie each other and thereby form a fluid-resistant joint between said shoes while permitting independent working of said shoes to accommodate irregularities in the tank shell face.

3. In a floating roof tank, seal means as described in claim 2 further including tensionally resilient spring means bridging the joints between adjacent shoes for maintaining the alignment thereof. 1

Claims

1. In a tank having a tank shell and a floating roof therein with clearance space therebetween, seal means in said space comprising a plurality of shoes arranged circumferentially about and with faces sealingly and slidably abutting the inner face of said shell, pliable sealing means extending continuously around said space and traversing the same radially between the upper portions of said shoes and said roof, additional sealing means nonrigidly connecting the adjacent ends of said shoes, and vertically disposed, generally bow-shaped spring straps with their center portions secured to the periphery of said roof and extending radially outwardly and upwardly and downwardly therefrom, the upper portions of said straps being rockingly secured to said shoes adjacent said upper portions thereof and beneath said pliable sealing means and the lower portions of said straps slidably abutting the inner faces of said shoes for resiliently supporting said shoes and said sealing means relative to said roof and biasing said shoes against the inner face of said tank shell.

3. In a floating roof tank, seal means as described in claim 2 further including tensionally resilient spring means bridging the joints between adjacent shoes for maintaining the alignment thereof.