US2426755A - Sealing means for floating roofs - Google Patents

Description

Sept. 2, 1947' R. c. ULM 2,426,755

' SEALINQ MEANS FOR FLOATING ROOFS Filed June 12, 1944 4 Sheets-Sheet l I 1 fl I 4 I INVENTOR. 15 I 72 6'. ZZLm, Q BY 1' l V v I v M 1 444 gm. I L 4' p 1947- R. c. ULM 2,426,755

SEALING MEANS FOR FLOATING ROOFS 1 Filed June 12,. 1944 4 Sheets-Sheet 2 Patented J 1s UNITED STATES PATENT orrlcs "SEALI-NG MEANS FOR rnoa'rmo noors 1mm 0. Ulm, East Chicago, ma, asslgnor a Graver Tank & Mfg. C

0., Inc., East Chicago,

Ind a corporation of Delaware Application June 12, 1944, Serial No. 589,915

space while maintaining the pocket of gaseous. vapors trapped by the sealing means to a minimum to reduce the flre hazard.

Another object is to provide sealing'means for a floating roof which will utilize the vapor pressure of the liquid to maintain a flexible fabric seal in sealing contact with the cylindrical wall of the tank.

A further object resides in the provision of structure. for sealing a. floating roof having a flexible fabric seal extending around the tankwall and depending in close proximity to the wall whereby the fabric seal clings to the tank wall by reason of its flexibility andby the further fact that the trapped vapors exert pressure to force the same outwardly into contact with the tank wall.

Another object is to provide fabric sealing I means for a floating roof which will be flexibly sensitive to pressure so as to effect a seal as a result of the trapped vapor pressure during periods of evaporation, and which will hang free of the tank side walls at low temperatures when practically no evaporation takes place.

With these and various other objectsin view the invention may consist of certain novel features of construction and operation as will be more fully described and particularly pointed out in the specification, drawings and claims appended hereto.

In the drawings which illustrate an embodiment of the invention andwherein like reference characters designate like partsa Figure 1 is a vertical sectional view showing part of a floating roof tank equipped with the sealing means of the invention;

Figure 2 is a fragmentary top plan view of the roof and sealing means shown in Figure 1;

Figure 3 is a. fragmentary view from inside. the tank showing in elevation the sealing means of Figure 1;

Figure 4 is. a vertical sectional view showing part of a. floating roof tank equipped with a modi- 2 fled form of sealing means coming within the invention;

Figure 5 is a fragmentary top plan view of the roof and sealing means shown in Figure 4; and ,j

Figure 6 is a fragmentary view from inside the tank showing in elevation the sealing means of Figure 4.

The apparatus selected for illustrating the modification shown in Figure 1 consists of an open top tank indicated by numeral it, containing volatile liquid H, such as gasoline, on the surface of which floats the deck or roof I! of the pontoon type. To permit the roof to rise and fall as the level of the liquid in the tank varies the roof has a diameter slightly less than the diameter of the tank. Therefore the annular space between the rim l3 of the roof and the cylindrical wall of the tank Ill permits evaporation of the liquid and the vapors would escape were it not for the peripheral sealing means of the invention. The fabric seal does not restrict the free movement of the roof in a vertical direction although the space is effectively sealed in a manner maintaining the pocket of gaseous vapors trapped by the sealing means to a minimum to reduce the fire hazard;-

The structure of Figure 1' essentially comprises a fabric seal it which extends completely around the inside of the tank so as to have contacting relation with the cylindrical wall iii of the tank. The flexible fabric seal it is continuous around the tank and the same may be constructed of any flexible material capable of withstanding corrosion and abrasion. Thus the seal may comprise a plastic impregnated fabric, synthetic rubberized fabric, screen or ply-cord.

It will be noted that this flexible fabric seal M constitutes a curtain or sleeve which is generally parallel to the tank wall, with the major part or section being substantially cylindrical like the tank wall. This is particularly true of that portion of the curtain adjacent the liquid level. Inasmuch as the seal it is made of flexible fabric the same can be described as an endless, unitary, substantially cylindrical curtain of uniform, flexible, vapor-tight fabric. It will be further noted that this seal or fabric curtain extends freely and unobstructedly fromabove to below the liquid level in the peripheral space between the roof and the tank side walls andrelatively adjacent the said walls.

Pivoted hangers it are provided for suspending the flexible seal in close proximity to the tank shell It. A plurality of such hangers are employed, located in spaced relation around the 3 floating roof, and each hanger is pivotally'secured to the roof by means of fixed brackets H. The lower end of, each hanger is bifurcated, as shown in Figure 3, to form pivot members l8,

each disposed adjacent. the inside surface of a fixed bracket ll. The parts are connected by the pivots 20. They opposite end .of each hanger is. likewise bifurcated to provide spaced pivot members 2|, as best shown in Figure 2 and the members are operatively associated with an adjustable bracket 22. I fabric seal i4 and the enclosing fabric 24 are clamped between the metal toe 25 and the angle member 26. The toe is held to the angle member by the fastening means 21 and by clamping the flexible seal l4 and the enclosing fabric 24 between said metal parts it will be understood that a vapor-tight seal is produced, the same extending completely around the tank. If desired the clamped portions of the fabric may be glued together or said fabric may comprise a single piece of material having the clamped portion bent upon itself.

The horizontal portion of angle member 26 'supportsthe upright threaded bolt 28 by means of which the bracket 22 maybe secured in any position vertically of said bolt. Fastening means or nuts 30 and 3| hold said bracket in the desired position on said bolt. The bolt 28 may be welded or otherwise suitably secured to the horizontal portion of its angle member 26 and said bolts are located in spaced relation around the tank in alignment with the hangers. The'gaseous vapors which may be generated above the space surrounding the roof are trapped and confined to said space by the enclosing fabric 24 having its upper end suitably clamped or forming a part, of the fabric seal M whereby a vapor-tight connection is provided. Th'elower end of the enclosing fabric is also vapor-tightsince this end is fixed tothe fioatingroof so as to form a seal with said roof. Said lower end of the enclosing fabric is clamped betweenthe angle member 32 forming part of the roof and the metal strip 33. Any

suitable means may be provided for holding the parts in clamped relation, Fig. 1 illustrating the use of wedge members 34 for applying the necessary pressure to the metal strip 33 at spaced points to thus hold the enclosing fabric 24 securely clamped to the angle member 32 of the roof.

The seal I4 provides a depending flexible curtain n the inside of the tank shell and which is supported by the hangers l6 so as to depend relatively adjacent the side wall of the tank.

The connection of the hangers to the roof by the pivots 20 renders the flexible seal movable toward and from the tank shell and such movement is absolutely essential in sealing means of this type since the tank shell has inside joints, projecting rivets and the like, which would otherwise prevent sliding action of the sealing means on the tank shell, These factors also render it desirable to pivot the flexible seal i4,-the metal toe 25 and arcuate member 26 from the upper end of the hangers. As a result the metal toe is able to pass over lapped joints, rivet heads and other projections, which action is facilitated by the curved upper end of the metal toe.

In Figures 2 and 3 the metal toe 25 and the angle member 26 are arranged in arcuate sections, eachsegmental section having approximately three hangers for supporting the same.

Thus, each section is largely an individual unit capable of movement to and from the side walls of the tank independently of adjacent sections.

The top of the flexible The flexible seal i4 and enclosing fabric 24 are of course continuous, it being understood that the fabric between sections will have some looseness so as to accommodate itself to the tank side wall as the circumference thereof may vary.

Attention is directed to the folds 29 formed in the upperportion-of the flexible fabric seal as shown in Figure 1. Said figure shows the seal in contact with the tank shell except adjacent the v folds 29. It will be obvious that due to the flexible nature of the seal these folds can be straightened outand the diameter and periphery of the seal increased thereby if the same could be taken from the tank and fully expanded. In this sense a the seal can be described as having a free peripheral length slightly in excess of the inside peripheral length of the tank shell. This feature is very important inasmuch as it provides for improvedsealing contact with the tank shell produced by the vapor pressure above the liquid trapped by the sealing structure.

In operation of the sealing means shown in Figure 1 it will be understood that upon evaporation of the volatileliquid around the periphery of the roof the generated vapors will be trapped by the fabric seal M and enclosing fabric 24. Since the fabric seal is sensitive to pressure the same is actually forced into contact .with the tank shell by the vapor pressure within the peripheral space thus closed off by the sealingmeans. The fabric seal is caused to take the shape of the tank and contact between the two surfaces results in sliding action when the level of the liquid changes. In the event the vapor pressure should drop to zero, or if a vacuum should develop, the fabric seal [4 will nevertheless hang close to the cylindrical wall of the tank by the action of the weights IS. A plurality of weights 15 or one continuous weight may be added to the fabric seal l4 at the lower. end thereof in order to counteract any lifting action of the seal which may tend to lift the same from the volatile liquid II. In actual practacting relation'with the cylindrical wall ill! of the tank. The fabric seal may be constructed of any suitable fabric such. as described in connection with Figure 1. The fabric seal. H4. and enclosing fabric I24 are joined together at their upper ends so as to form an airtight enclosure around the periphery of therocf. One piece of fabric may be employed, being bent upon itself at its upper end, which portion is suitably secured to the segmental angle members I26 by means of the metal retaining bar I25. Said bar in each instance is secured to its particular angle member by means of the screws I21.

Pivoted hangers H6 are provided for suspending the flexible seal in close proximity to the tank shell H0. A plurality of such hangers are em-' ployed and as shown in Figures 5 and 6, each segmental angle member is supported by one hanger, having connection therewith substantially centrally of the same. Each hanger is pivotallysecured to the roof. by means of fixed brackets H1. The lower end of each hanger is adjustably secured to a yoke member H8 having laterally extending pivots I20 supported by the fixed brackets. Each hanger at-its upper end is bifurcated, providing spaced pivot members I2I which straddle a plate bracket I22 suitably fixed as by welding to the inside-surface of the segmental angle member I28. The parts are pivotally connected by means of the bolt I22.

The enclosing fabric I24 has a vapor-tight connection with the floating roof by means of the retaining bar I33 which clamps the fabric I24 to the angle member I32. Any suitable means may be provided for holding the retaining bar in clamped relation, Figure 4 illustrating the use of wedge members I34 which are forced between the bar and the metal plates I25 suitably welded to the base of the angle member I32.

In the modification of Figure 4 the weights are replaced by arcuate base angle members I21 which are operatively connected to the floating roof. The base angle members III are suitably secured to the lower end of the fabric seal by means of the retaining bar fabric to the angle members, being secured thereto by the screws I39. Each base angle member I31 is arcuate, having a shape similar to its corn-- panion member I26 at the top of the fabric seal. Both top and bottom angle members therefore substantially conform to the contour of the cylindrical wall of the tank. Each base member is operatively connected to depending struts or hangers I40. A transverse stud I is fixed to the upper end of each hanger I40 and is adapted toride within an elongated slot I42 formed in the spaced plates I43. At its opposite end each hanger I40 is bifurcated, having spaced plates I44 which straddle the plate bracket I45 suitably welded to the inside surface of the angle member approximately centrally of its arcu- Ill which clamps the the roof by means of 'be apparent to those the tank shell, a plurality of with the exception of the marginal portions where rigid members such as the hangers and partsconnected thereto must be secured to the seal.

This application is a continuation-in-part of my pending application Serial No. 505,480, filed October 8, 1943 and entitled Sealing means for floating roofs. 4

The invention is not to be limited 'to or by details of construction of the particular embodiment thereof illustrated by the drawings, as various other forms of the device will of course skilled in the art without departing from the spirit of the invention or the scope of the-claims.

What is claimed is:

l. In a liquid storage tank, the combination with a floating roof, of means-for sealing the peripheral space between the roof and tank shell including a plurality of arcuate hangers pivotally connected to the roof around the periphery thereof and extending upwardly and outwardly toward structural i members pivotally supported from the outwardly extending ends of said hangers, said members having location adjacent the tank shell and being arcuate in shape to substantially conform to said shell, a flexible fabric curtain supported from said members at its upper end so as to depend in close proximity around the inside of the tank shell, flexible fabric means extending from the periphery of the roof to said structural members for closing the peripheral space, whereby said space ate extent. This end of the hanger I is pivotally I connected to the plate bracket by means of the bolt I48. Oppositely directed hangers H4 and I40 therefore have connection with the top and bottom respectively of the fabric seal. "The bottom hangers I40 are, more positive than the weights described-in connection with Figure 1. The combination of hangers is desirable in connection with the use of a as II4 since considerable friction must be overcome to effect sliding movement of the seal on the tank walls. The seal is therefore under positive control at all times and it is immaterial whether the roof moves up or down. In moving up the retaining bar I25 which replaces the metal toe of Figure l, facilitates sliding movement over lapped Joints and other obstructions. when the roof moves downwardly the retaining bar I" directs this leading edge of the seal.

Freedom of movement for the present flexible seal is a necessary requirementsince the same must be freely movable toward The hangers merely make sible, although the same is facilitated by the pivoted connection of the hangers to the roof and by the pivoted connection of the arcuate members to the hangers. The excess peripheral length of the seal must also be considered in connection with the movability of the same since the combination of the several features results in a greatly improved sealing action. Vapors from-the volatile liquid in the peripheral spacebetween .the roof and the tank shell are trapped by the sealing means and they function to exert pressure in all directions. The structure is sensitive or responsive to such pressure pract cally throughout its area of contact with such trapped vapors,

the tank shell.

flexible fabric seal such such movement posis sealed in a vapor-tight manner and whereby the vapor pressure within said space will maintain the depending flexible curtain in contact with the tank shell, a metal retaining strip secured to each structural member for clamping portions of said fabric curtain and enclosing fabric thereto, each said metal retaining strip being adapted to have sliding contact with the tank shell upon movement of the floating roof, and a plurality of weights fixed to the lower end of the flexible curtain to facilitate movement of the same in a downward direction.

2. In a storage tank for volatile liquids having a floating roof, the combination of sealing means therefor including a plurality of hangers pivotally connected to the roof around the periphery thereof and having their opposite ends disposed adiacent the tank shell, a plurality of structural members pivotally supported from the opposite ends of said hangers, said members having location adjacent the tank shell and being arcuate in shape to substantially conform to said shell, a flexible fabric curtain extending around the inside of the tank and depending from the structural members in close proximity to the tank shell, flexible fabric having an outer part secured to the members and having its inner edge joined to the roof to thereby. enclose theperiph-' eral space between the tank and roof in a vaportight manner, whereby the said space upon evaporation of the liquid will result in maintaining the depending flexible curtain in contact with the tank shell, structural means flxedto the lower end of the depending flexible curtain, said structural means having location adjacent the tank shell and being arcuate in shape substantially similar connecting the structuraimeans to the floating roof.

3. In a storage tank for volatile liquids havinghangers vapor pressure within to that of the said structural members, and hangers operatively pivotally connected to the roof around the periphery thereof and having their opposite ends disposed adjacent the tank shell, a plurality of angle members pivotally supported from the op- V posite ends of said hangers, said members having location adjacent the tank shell and being arcuate in shape to substantially conform to said shell, a flexible fabric curtain extending around the inside of the tank and depending from the angle members in close proximity to the tank shell, flexible fabric having one peripheral edge secured to the members and having its other peripheral edge joined to the roof to thereby enclose the peripheral space between the tank and roof in a vapor-tight manner, whereby the vapor pressure within said space upon evaporation of the liquid will result in maintaining the depending flexible curtain in contact with the tank shell, a plurality of weights fixed to the lower end of the depending flexible curtain, and at least one lower hanger operatively connecting each weight to the floating roof, said lower hangers at'their ends having pivotal connection with the weights and roof respectively.

4. In a storage tank for volatile liquids having a floating roof, the combination of sealing means therefor including a plurality'of upper, hangers pivotally connected to the roof around the periph-.

ery thereof and having their opposite ends dis-" posed adjacent the tank shell, a plurality of angle members pivotally supported from the opposite ends of said hangers, said members having location adjacent the tank shell and being arcuate in shape to substantially conform to said shell, a flexible fabric curtain extending around the inside of the tank and depending from the angle members in close proximity to the tank shell, flexible fabric having one peripheral edge secured to the member and having its other peripheral edge joined to the roof to thereby enclose the periph eral space between the tank and roofin a vaportight manner, whereby the vapor pressure within said space upon evaporation of the liquid will I result in maintaining the depending flexible curtain in contact with'the tank shell, a metal wear strip secured to each angle member for clamping portions of the flexible" curtain and enclosing fabric to said members, structural 'means fixed to the lower end of the depending flexible curtain,

' and at least one lower hanger operatively connecting each said structural means to the periph-. ery of the floating roof.

5.'In a liquid storage tank, the combination with the side wall of the tank, of a floating roof, a vapor actuated, vapor retaining seal for the peripheral space between the roof and side wall I of the tank including a unitary, substantially cylindrical curtain of uniform, flexible, vaportight material, extending freely and unobstructedly from above to below the liquid level in the peripheral space adjacent the side wall, and havthe inside peripheral length of the side wall,.a flexible member having a vapor-tight connection with'said flexible curtain and with the floating roof above said liquid level to provide a closure for the space at the peripheral edge of the roof. whereby said curtain has close contact with the tank side wall as a result of the trapped vapor pressure during periods of evaporation, a plurality of upper hangers having inner ends connected to the roof around the periphery thereof and having outer ends disposed adjacent the side wall above said liquid level, a plurality of lower hangers having inner ends similarly connected and having outer ends disposed adjacent the side ing a free peripheral length slightly in excess of I wall below said liquid level, at least one structural member supported from the outer endoi" each upper and lower hanger'having location adjacent the side wall being arcuate in shape to substantiallyconform to said wall, and being secured to the top and bottom respectivelyof said curtain, whereby said upper and lower hangers respectively will force said curtain to follow said roof in its upward and downward travel.

6. In a liquid storage tank, the combination with the side wall of the tank, 01' a floating roof,

a vapor actuated, vapor retaining seal forthe peripheral space between the roof and side wall of the tank including a'unitary, substantially cylindrical curtain of uniform, flexible, vapor: tight material, extending freely and unobstructedly from above to below the liquid level in the peripheral space adjacent the side wall and having a free peripheral length slightly in excess of the inside peripheral length of the tank shell, a plurality of upper hangers pivotally fixed to the roof and extending upwardly therefrom toxadjacent the side wall, a plurality of members arouate in shape to substantially conform to the side wall having connection with said hangers, fastening means for securing the upper edge of the flexible curtain to said members whereby the curtain is suspended in a circumferentially expansible manner around the inside of the tank and in a close proximity to the side wall, a flexible annular member for closing the peripheral space above the liquid, said member having one peripheral edge secured in a vapor-tight manner to the flexible curtain and having its other edge secured to the roof, a plurality of lower hangers pivotally fixed to the roof and extending therefrom to adjacent the side wall, a plurality of members arcu-' ate in shape to substantially. conform to the side wall having connection with said lower hangers and fastening means for securing the lower edge of the flexible curtain bers. I

7. In a liquid storage tank, the combination with the side wall of the tank, of a'floating roof,a vapor actuated, vapor retaining seal for the peripheral space between the roof and side wall of the tank including a unitary, substantially cylindrical curtain of uniform, flexible, vapor-tight material, extending freely and unobstructedly from above to below the liquid level in the peripheral space adjacent the side wall, and having a free peripheral length slightly in excess of the inside peripheral length of the tank shell, a plurality of supporting means located above said liquid level and supported by the floatingroof for suspending the flexible curtain around the inside of the tank in close proximity to the tank shell, a flexible member having a vapor-tight connectionwith said flexible curtain and withthe floating roof providing a closure for the space, at the peripheral edge of the roof, whereby said P curtain provides a seal with the tank side walls as a result of thetrapped vapor pressureduring periods of evaporation, structural means flxed to the lower edge of the flexible curtain, and connecting means having pivoted connection with the roof and withthe structural means respecv tively for operatively connecting said structural means to the roof, said connecting means comprising hangers which extend downward and outward from the roof.

8. In a liquid storage tank, the combination with the shell of the tank, of a floating roof, a

' vapor actuated, vapor retaining seal for the peripheral space between the roof and the tank to said last named mem- 9 v shell including a unitary, substantially cylindrical curtain of uniform, flexible vapor-tight material, extending freely and unobstructediy from above to below the liquid level in the peripheral space adjacent the tank shell, and having a free peripheral'length slightly in excess of the inside peripheral length of the tank shell, a plurality of hangers fixed to the roof and extending upwardly therefrom adjacent the tank shell, a plurality of members arcuate in shape to substantially conform to the shell having a pivotal connection with said hangers, fastening means for securing the upper edge or the flexible curtain to said members whereby the curtain is suspended in a circumferentially expansible manner around the inside oi? the tank and in close proximity to the tank shell, a flexible annular member for closing the peripheral space above the liquid, said member having one peripheral edge secured in a vapor-tight manner to the flexible curtain and having its other edge secured to the roof, a plurality of 16 Number weights fixed to the lower edge of the flexible curtain, said weights having location adjacent the tank shell and being arcuate in shape substantially conforming to that of said members, and means having connection with the root and with the weights respectively for operatively connecting said weights to the root,

REIGN C. ULM.

unreal-Incas orrrzn UNITED STATES ZPATE'NTS Name Date 2,318,134 Wiggins May 4-, 1943 1,426,999 I Leland et a1. Aug. 22,1922 2,082,194 June 1, 1937 1,979,657 2,287,211

- NOV. 6, 1934

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