US2036372A - Floating deck for oil storage tanks - Google Patents

Description

April 7, 1936.

J. A. STOUGH FLOATING DECK FOR OIL STORAGE TANKS Filed Aug. 1, 1930 man xxx

2 Sheets-Sheet 1 I 'Ill NVENTOR l l" h ATTORNEY April 7, 1936. J. A. STOUGH 2,036,372

FLOATING DECK FOR OIL STORAGE TANKS Filed Aug. l, 1930 2 Sheets-Shea#l 2 w N 41 Q y l INVENTOR Qllq Q TToNv lll dll

hull

ltatenteel Apr.. W, l

atteste impartite nnen ron om eronder: ranks lay n. dtough, Tulsa, lDlkla., assigner to @tough llank lErecting Company, llulsa, @klas a cor-1 poration of @klahoma Application August ll, illlll, Serial No.. 472,25@

tl Claims.

lVfy invention relates to storage tanks and more particularly to noating roofs for storage tanks, the principal object of the invention being to provide for thermo-breathing of the roof, an action resulting from expansion and contraction due to variations in the temperature of a layer of gas collected on the body of oil in the tank below the roof, and tol permit such breathing of the roof without loss of the collected gas.

Other important objects of the invention are to provide effective sealing means for roofs of this character, to embody simple and emcient drainage for the roof and to provide inexpensive means for guiding and centering the roof in the tank.

ln accomplishing these and other objects of my invention l have provided improved details of structure the preferred form of which is illustrated in the accompanying drawings, wherein:

Fig. 1 is a perspective view of a tank in central cross section equipped with a floating roof embodying my invention.

Fig. 2 is a fragmentary perspective view of the sealing means, guide means and an annular pontoon.

Fig. 3 isa fragmentary perspective view, partly in section, of the ladder and mounting therefor.

Fig. l is a perspective view of associated sections of the annular pontoon.

Fig. 5 is a perspective View of a rectangular pontoon secured to a roof section and shown in inverted condition.

Fig. '6 is a detail perspective view of a brush element.

Fig. 7 is a view in perspective of a guide wheel mounting,

Referring more in detail to the drawings:

l designates a storage tank of a form commonly used for storing petroleum products, and

includes a bottom t and an annular side wall il Y built up of sections ll, the upper end of one section snugly receiving the lower edge of a superimposed section. The upper end of the wall terminates in an 4outwardly `directed annular ledge t, braced from the side wall in the usual manner as indicated at li. y

A roof l, adapted to float on the body of liquid in the tank, comprises a plurality of metal sheets t, secured together as by welding to form a circular roof complementary to the tank wall; a space il being reserved between the roof and the wall to accommodate nexible sealing means as later described for'retarding escape of huid suchl as gas from within the tank, and to prevent, to a great ektent 'the entrme of water into the (lill. 2920-26) upper portion of the body of liquid in the tank.

Alternate sections of the roof are preferably provided with pontoons lll formed rectangular in shape complementary to the sections and welded to the lower sides thereof as indicated at ll, the principal object for securing the pontoons to the roof sections in this manner beingthat the sections may thus be provided with pontoons before they are assembled to form a continuous roof, and that a pontoon member may be welded to a roof section in inverted condition as shown in Fig. 5 of the drawings, thus eliminating overhead welding, and thereby reducing the cost of construction.

ns shown in Fig. l of the drawings, an annular pontoon ll? is provided on the periphery of the roof to prevent sagging of the outer edge of the roof under heavy loads of snow and ice. This annular pontoon is preferably constructed by providing a continuous vertical band lt around u the outer edge of the roof which' is welded thereto as indicated at lll, a relatively narrow portion of the band extending above the surface of the roof and the remaining portion projecting beneath the roof to a `point below the lower surface of the pontoons.

The pontoons are so designed that they will ordinarily be partially submerged in the body of oil in the tank, and 'the purpose for extending the lower edge of the band to a pointbelow the lower surface of the pontoons is to prevent escape ofA gas collected on the oil in the tank when the gas is sufficiently expanded, due to excessive heat, to elevate the pontoons entirely out of the oil.

A metal sheet lb, having an arcuate edge lt m conforming to the peripheral band, is then bent at right angles as indicated at ll, to produce a lower wall lt and an inner wall i9 welded respectively to the annular band and to the roof l. One end of each of these pontoon sections is then closed by an end wall tt, and the open end of a following section is next welded thereto so that the annular pontoon will be divided into individual sections of equal length and leakage of one section will not effect the buoyancy of an adjacent section.

The portion of the band extending above the roof serves as a support for an annular seali 1g member ll comprising a series of wiping elements or brushes lf; The bristle-like members 2t of the brushesl are preferably impregnated with an acid-resisting solution to neutralize the action of acids in the oil, and are embedded in a head lll which is preferably formed of metal and includes integral bolts tb adapted to be received ii complementary openings 26 formed in lthe upper portion of the circular band, and nuts 2T are threaded on the bolts for securing the brushes to the band.

With this method of mounting the sealing Y members, worn brushes may be readily replaced without removing the roof from the body of liquid whereon its rests.

In order to maintain the roof in a substantially central position in the tank and to prevent rotation thereof on the body of liquid, centering means are provided including a plurality of wheels 28, rotatably carried between spring leaves 2li and 36 having loop portions 3l and 32 at their upper and lower ends respectively. The lower loops 32 are pivotally mounted on bolts 33 extended through ears 3Q of brackets 35 secured to the roofl by welding or the like, and the upper loop portions of the springs are adapted to receive bolts 3@ extended through the loops and through the hub of a wheel 28.

U-bolts 3l, engaging the spring members intermediate their ends, are extended through openings 38 formed adjacent the upper edge of the annular band, and are secured thereto by nuts 39.

Vertical guide members lll preferably in the form of channel irons are mounted in the interior of the tank for receiving the rims of wheels di, thereby maintaining the roof in centralposition on the liquid. A flexible mounting for the wheels is thus provided to compensate for irregularities of the tank wall such as the laps of successive.

sections of the wall.

The roof declines toward its center for drainage purposes and is provided with an opening di cooperating with telescoping drain members l2 comprising a plurality of tubular sections adapted to telescope into each other; each section having an inwardly directed ange Ml on one end and an outwardly directed flange l5 on its 'opposite end so that said ilanges will serve as means `for guiding and limiting the extension of one tubular section onv its adjacent section.

The lower end of the bottom section is preferably provided with notches 41.6 to permit egress of lladder di; for the tank roof, spaced brackets il@ and 5D having foot portions 5i are fixed to the ledge 5 of the tank by bolts or the like 52. 'The upper portions of the brackets terminate in bearings 53 for journalling a shaft 54 carrying flanged wheels 55.

The ladder preferably comprises chains 5G spaced by barsli'i, serving also as rungs, and the chains are reeved over the rims of the Wheels 55. The inner end of the ladder is secured to the floating roof as indicated at 59 and the outer end thereof is provided with a counter-weight 6d to maintain the chains in taut condition and to counteract the weight of an operator ascending or descending the ladder.

Manholes 6l and test openings 62, normally closed by lids 63 and 64 respectively, may be provided at any convenient location in the floating roof.'

Assuming a storage tank to be provided with a.

floating roof constructed and mounted therein as described, the action of the roof on the body of liquid in the tank would be as follows:

Due to the annular pontoon surrounding the outer edge of the roof and to the intermediate rectangular pontoons the roof will be supported in a substantially level relation with the tank. As the roof moves either upwardly or downwardly with the changing liquid level in the tank the Wheels move correspondingly in the grooves to prevent rotation of the roof on the liquid.

Through provision of the lower edge portion of the band extending below the pontoons and into the body ofv oil under conditions when the pontoons are raised above the surface of the oil, breathing of the roof is permitted without loss of gas from the tank.

Irregularities in the tank wall and variations in the diameter thereof are compensated for by the flexibility of the brushes, and escape oi gas and like luids from the body of liquid is thereby further prevented.

Rain and melted snow accumulating on the roof drains toward its center and passes through the telescoping drain to the tank bottom below the lower surface of the oil and may be drained from the valve outlet as frequently as necessary.

The ladder, maintained in taut condition by the counter-weight, is available at all times for operators descending on the tank roof for making tests and the like.

From the foregoing description it will be apparent that I have provided an ecient iioating roof for storage tanks that can bev manufactured at a cost that is not prohibitive and that will give long and satisfactory service.

What I claim and desire to secure by .Letters Patent is:

l. In combination with a storage tank, a roof spaced from the tank wall and adapted to ioat on liquid in the tank, a peripheral band surrounding the edge of the roof with a portion of said band extending above the roof, sealing means on said upwardly extending portion for closing the space between the roof and wall, a peripheral pontoon for the roof, comprising an inner wall secured to the-roof and a lower wall secured to a portion of the band extending below the roof, and a skirt on said peripheral band extending downwardly below said pontoon.

2. In combination with a storage tank, a roof spaced from the tank wall and adapted to oat on liquid in the tank, a peripheral band surrounding the edge of the roof with a minor portion of the band extending above the roof and a major portion of said band extending below the roof, sealing means on said upwardly extending portion for closing the space between the roof and wall, a peripheral pontoon comprising an inner wall fixed to theroof and a lower wall xed to the downwardly extending portion of the band for supporting the roof, and a skirt` comprising the extreme lower end of said band and projecting below said pontoon.

3. In combination with a storage tank, a roof spaced from the tank wall and adapted to oat on liquid in the tank, a peripheral band surrounding the edge of the roof with a portion of said band extending above the roof, sealing means on said upwardly extending portion for closing the space between the r'oof and wall, resilient roofcentering means pivotally mounted on the roof and means for anchoring said centering means to said upwardly extending portion.

lill

di. In combination with a storage tank, a roof spaced from the tank wall and adapted to iioat on liquid in the tank, a peripheral band surrounding the edge of the roof with a portion of said band extending above the roof, sealing means on said upwardly extending portion for closing the space between the roof and wall, spaced re- .-si1ient arms pivotally mounted on thereof, a

rounding the edge of the roof with a portion of said band extending above the roof, sealing means on said upwardiyextending portion for closing lto saidupwardy extending `portion, and vertical guide members on the tank wall adapted to be engaged by saidfcentering means.

6. A roof for storage tanks including a peripheral band surrounding the edge of the roof with a portion ofsaid band extendingbelow the roof, and an annular pontoon for the roof comprising individual angular sections having lower and inner walls secured respectively to said band and to theiower surface of the roof, each section having an open end and an opposite closed end adapted to abut the open end of an adjaoent section..

JAY A. STOUGH.

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