US1921877A

US1921877A - Floating roof for tanks

Info

Publication number: US1921877A
Application number: US483536A
Authority: US
Inventors: George V Hackett
Original assignee: Standard Oil Co
Current assignee: Standard Oil Co
Priority date: 1930-09-22
Filing date: 1930-09-22
Publication date: 1933-08-08
Anticipated expiration: 1950-08-08

Description

Aug. 8, 1933.

G. V. HACKETT FLOATING ROOF FOR TANKS Filed Sept. 22, 1930 Patented Aug. 8, 1933 v UNITED STATES `PATENT oEFiCE FLOATINC QB001 FOB TANKS George V. Hackett, Independence, Mo., assignor to Standard Cil Company, (Indiana), Chicago, Ill., a Corporation of Indiana l Application September 22, 1930 Serial No. 483,536 v n escape of vapors.

Tank roofs of the character to which reference is made ordinarily employ a metallic shoe which is made in sections connected by flexible material and extends entirely around the interior side wall of the tank in sliding contact therewith so that as the roof rises'` and falls theshoe slides up and down along the wall maintaining a substantially tight contact therewith. A resilient support connecting the shoe with the tank roof permits the shoe, to give inwardly or outwardly under relative .expansive or eontractive movements of the tank, the shoe or the roof so as to maintain this tight' contact between the shoe and the tank wall. :inasmuch as the shoe must be spaced outwardly from the edge of the roof which is of less diameter than the diameter of the tank, and inasmuch as expansionv and contraction between the several parts take place under varying conditions, it is necessary, in order to prevent vapor loss, to provide a flexible seal between the shoe and the roof proper. Ordinarily a piece of impervious composition fabric of the character now well known in the art is connected between the shoe and the tank root proper and sufficient fabric is used to permit'the shoe to move outwardly from the roof the maximum distance which may occur. Heretoiore the fabric has been so attached to the shoe and -roof proper that under all normal conditions and positions of the fabric, shoe and roof the fabric has bowed down between the shoe and roof thereby providing a pocket extending circumferentially over the roof for the reception of dirt and moisture, which very quickly rots the fabric or causes .it to disin\ tegrate with resultant leaks. When there are vapor leaks in tanks suchl as those containing gasoline or other volatile fluids, losses may become very serious-and costly and frequent inspections must be made to ascertain whether or not the. fabric seal is in good condition. ,i If the fabric seal is `leaking or is showing signs indicating disintegration, it must be replaced or repaired and this has been found to entail con- Asiderable expense. Many attempts have been made to overcome these difilculties and to avoid these costly replacements and repairs but, so

far as I am aware, no :one prior to my invention has been successful.

One of the primary objects of my invention Yis to provide a fabric seal for sealing the space between the shoe and the tank roof so 'con- 60 structed and arranged that it will. not channel or bow downwardly and collect dirt yor water. The mconstruction and arrangement are such that wateror dirt and other debris falling upon the fabric`seal cannot well remain thereon and will run olf onto the roof 4 and into a drain or other place of disposal connected with the roof. In this manner the life of the fabric seal is prolonged considerably over the life of former fabric seals which guttered, collected and held 70 dirt and water. A

Further objects of the invention will bel/for should become apparent and understood Vafter reading the following description and claims and after viewing the drawing in which:

Fig. 1 is a more or less diagrammatic sectional view of a floating roof tank with a preferred form of my invention applied thereto.

Fig. 2 is an Aenlarged sectional detail illustrating the application of a preferred form of my invention to a floating roof tank and Fig. 3 is a view similar to that-of Fig. 2 illustrating a modified arrangement with certain of the mechanism, connecting the shoe and the roof proper, omitted for the purpose of simplicity.

A tank generally designated 2 has a bottom 3 and a side wall 4. A floatingv roof generally designated 5 rests upon and is supported by the uid within the tank. A mast '6 at the center of the roof and guy wires 7, running from the mast to the outer circumference of the roof at circumferentially spaced places, serve to support the outer portions of the roof and to give the roof a pitch radially inwardand downwardly Atoward the center at which place a trap 8 is placed and connected with pantograph pipe 9 through which water and dirt drain downl from the roof and may pass tothe exterior of the tank. Turnbuckles 11 may be used to tension the guy wires' 7 as desired.

The roof may be provided with a circumferentially yextending upstanding 'iiange4 12 to which the seal and the sliding shoe support are connected. In the embodiment illustrated, a 105 circumferentially extending channel 13 is secured in any suitable manner to the upper end of the flange 12 while a series of cleats 14 are secured to lower portions of the flange 12. Pivotally connected at 15 to each cleat is a bent supsecured to the sliding shoe or shoe section 19.

A bar 21 is rigidly secured at one end, as by welding, to the bar 16 and at its other end is adapted to be pivotally connected as at 22 to a toggle bar or rod 23 through any one of several eyes 24, which are provided for the purpose of adjustment., A spring 25, connected between the toggle bar 23 and the interior rim' of the channelA 13, tends to pull the supporting bar 16 in a counter clockwise direction about the pivot 15 and thereby urge the shoe tightly against the interior wall of the tank. A cleat 26 is welded, or otherwise rigidly secured to the upper leg of the bent supporting rod 16 and has an eye therethrough through which the threaded end of an eye screw 27 passes. \A nut 28 serves to secure the eye screw 27 to the'cleat and by adjusting this nut the tension on a spring 29, connected between the eye screw 27 and the upper end 31 of the cleat 18, may be adjusted. Spring 29 tends to pull the cleat 18 and thus the shoe 19 in aclockwise direction about the pivot 17, thereby tending to raise the shoe upwardly with respect to the roof proper and to urge the shoe, at least at its lower portion, tightly against the interior surface of the tank wall.

Inasmuch as the construction above described requires a space between the shoe and the flange 12, through which considerable amounts of vapor might escape, some means of sealing the space must be provided. `In the illustrated embodiment, a piece of composition coated fabric 32 of ample width to span the maximum required space between the shoe and ange 12 is tightly sealed at its outer end 33 to the upper end of the shoe. The inner end of the fabric strip is looped over the roof in such manner as to presenta convex surface tothe exterior of the tank and is then secured and sealed in any suitable manner, as at 34, to the top of the channel 13. A tight seal is effected between the fabric and shoe and between the fabric and channel circumferentially of the roof. The fabric is so attached to the shoe and to the roof structure that, together with the stiffness of the fabric and the internally convex loop, as-

-illustrated and described, the fabric seal slopes gradually downwardly from the shoe to a place over the roof proper and will maintain this position under relative movements between the shoe and roof proper. When water or debris falls upon the top surface of the fabric seal 32, its normal tendency will be to roll dovm onto the roof proper and from thence to the trap and drain in the center.A Guttering ofthe fabric seal is prevented and the seal will last longer.

In the modified arrangement illustrated in Fig. 3, the upstanding iiange 35 has an angle 36 secured to it at its upper marginal edge and the fabric seal 37 is attached and sealed to the underside of the horizontal leg of the angle. The outer edge of the fabric curves downwardly instead of upwardly and is then sealed to the inner side of the shoe 38. In this case cleat 39, corresponding to the cleat 18, is preferably secured to the outer side of the shoe, the remainder of the construction being similar to the construction previously described. It will be observed that the fabric seal in this form assumes the shape (in cross section) of the letter 0" and will hold this shape even under considerable movements of the shoe away from the roof proper. The natural stiffness or body of the fabric, together with the looping, will prevent any channeling or guttering with its consequent detrimental effects, from taking place.

While I have illustrated and described the invention in several forms, applied to one particular type of iioating roof construction, it should be understood that in its broader aspects it is susceptible of other applications and arrangements. Consequently I do not desire to be limited except by the spirit of the invention and the scope of the appended claims.

l. In a floating roof construction for tanks, a roof member, a shoe for sliding contact with the tank wall, means securing said shoe to said roof member, and a flexible sealing member connected to and between said shoe and roof member, said sealing member normally having an inner portion looped over the roof, the portion of said sealing member between said looped portion andv shoe being normally inclined upwardly and outwardly to said shoe.

2. In a iioating roof construction for tanks, a roof having an upwardly directed fiange about its perimeter, a shoe connected to said roof for movements therewith and relative thereto for sliding engagement with the interior wall of the tank, means normally urging said shoe from said roof toward said tank wall, and a seal of flexible sheet material connected to and between said shoe and said flange, said sheet material being of greater linear surface dimension from said shoe to said flange than the shortest distance between the places of connection of said sheet to said flange and shoe, the excess of said sheet being looped over said roof inwardly of said flange, said loop presenting a convex surface away from said roof and flange.

3. In a floating roof construction for tanks, a roof having an upwardly directed flange about its perimeter, a shoe connected to said roof for movements therewith and relative thereto for sliding engagement with the interior wall of the tank, means normally urging said shoe from said roof toward said tank wall, and a seal of exible sheet material connected .to and between said shoe and said flange, said sheet material being of greater linear surface dimension from said shoe to said fiange than the shortest distance between the places of connection of said sheet to said flange and shoe; the excess of said sheet being looped over said roof inwardly of said flange, said loop presenting a convex surface 'away from said roof and ilangesaid sheet having one side at one'edge fastened to said shoe in a substantially vertical plane and its other side at the opposite edge fastened to said flange in a substantially horizontal plane, said sheet under normal conditions sloping downwardly iand inwardly of the tank from said shoe to Said oop.

4. In a device of the character described, a roof adapted to iioat on a uid in a tank, a. shoe supported from said roof for sliding engagement with the side wall of the tank, and a seal of fiexible material extending between said roof and shoe and projecting over the joint between the roof and flexible material, said material being so fastened to said roof and shoe as to flex the material upwardly and inwardly with respect to the tank to provide a convex surface directed substantially skyward.

' GEORGE V. HACKETI'.