US2649985A

US2649985A - Seal hanger for floating roof tanks

Info

Publication number: US2649985A
Application number: US227188A
Authority: US
Inventors: Frederick D Moyer
Original assignee: Chicago Bridge and Iron Co
Current assignee: Chicago Bridge and Iron Co
Priority date: 1951-05-19
Filing date: 1951-05-19
Publication date: 1953-08-25
Anticipated expiration: 1970-08-25

Description

5, 1953 F. D. MOYER 2,649,985

I SEAL HANGER FOR FLOATING ROOF TANKS Filed May 19, 1951 l aten'ted Aug. 25, 1953 SEAL HANGER FOR FLOATING ROOF TANK-S Frederick D. Moyer, Chicago, 111., assignor to Chicago Bridge & Iron Company, a corporation of Illinois Application May 19, 1951, Serial No. 227,188

8 Claims. 1

This invention relates to a liquid storage tank and more particularly to .such a tank employing a floating roof in which .a particular hanger means is used to support asealing ring in contact with the tank shell.

Liquid storage tanks having floating roofs are in wide use especially in the petroleum industry. The floating roof is ofs'lightly smaller diameter than the storage tank, leaving a small annular space about the roof which must be sealed from the elements. This scaling is accomplished by covering the space with a fabric seal extending between the roof and a sealingring held in contact with the tank shell. This sealing ring has one or more shoes each in sliding contact with the tank wall and held in that position by a hanger means. Previous hangers have been cumbersome and complicated in operation. Those which have proved successful have had the distinct disadvantage of requiring that the roof remain a substantial distance "above the bottom of the tank at all times.

The present invention is concerned particularly with a new and improved hanger means for supporting the sealing ring about a floating roof. Several advantages are present in the hanger of this invention in that it supplies forces tending to center the roof within the tank while at the same time pressing and maintaining the shoes of the sealing ring in contact with the tank wall. These forces are applied by -a portion of the hanger device which is rendered partially inoperative as the roof approaches its lowermost position in the tank, and as the roof comes to its lowermost position the hanger device then serves as a roof support. The' hanger permits the floating roof to rest in a'much lower position within the tank than has been possible with previous successful hanger devices without interfering with other desirable features-of the hanger.

The invention'will bedescribed with reference to a particular embodiment illustrated in the accompanying drawings in which Fig. l is a vertical sectional broken view through the tank wall of a floating roof tank showing the particular hanger means of this invention. Fig. 2 is a fragmentary vertical sectional view taken as indicated by line 2-2 in Fig. 1. Fig. 3 is a horizontal fragmentary sectional view taken as indicated by line 3-3 inFig. 1.

Fig, 1 of the drawings illustrates-a liquid storage tank having sidewalllfl whichiscylindrical generally, and containing .a liquidlll upon-which floats a floating roof 12. The roof has a lower deck l3 and an upperdeck l4 securedtogether in liquid-tight relation at the periphery of the 2 roof by a substantially vertical rim 15. It will be understood that the floating roof I2 forms no part of this invention and may take various shapes and designs as desired.

The floating roof I2 is of smaller diameter than the shell N3 of the tank, leaving an annular space It between the floating roof and the shell when the roof is centered therein. A sealing ring 5'! extends around the floating roof and comprises shoes !8 in contact with the shell IQ of the tank. The space i6 is sealed by a fabric it, annular in shape, and extending between the sealing ring and the upper peripheral edge of the roof l2. The sealing ring is "provided with an outwardly turned upper edge to which the fabric is secured so that the space [6 is sealed from the atmospheric elements so long as the shoes 58 of the ring are held against the tank shell Hi.

The particular hanger means which comprise the subject matter of this invention include a supporting lever bar having like parallel portions 26 and 21 secured together to act as a unit as more fully appears in Fig. 2. A lug 28 is fastened to the upper portion ofthe rim [5 of the floating roof and a pivot pin 29 pivotally secures the parallel portions 26 and 2'! of the supporting lever bar 25 to the lug 28. The lever bar is provided with an angular portion '30 at its lower end, it being understood that the parallel portions 26 and 21 are alike. An intermediate portion extends downwardly from the "pivot pin 29 to the angular portion 30 and in the-space between the roof and shoe. The angular portion may of course be limited to the area adjacent the shoe, but there is no objection to curving the intermediate portion or the weightarm to'make a long continuous curve.

The shoes 58 are supported by'the supporting lever bar by means of a shoe bar'ilii pivotally connected to a lug 36 secured tot-he shoe 88. A pivot pin 3? extends throughthe bar and lug 3G to provide the pivotal connection. This shoe bar 35 extends downwardlyfrom the pivot pin .3'l in the space betweenthe roof and shoe to a pin and slot connection with the lower peripheral edge of the roof. Thus a fixture-38 having a vertical slot 39 therein is secured to the roof'to provide a vertical track for a pin 40 connected-to the lower end of the shoe bar-to travel in. This connection permits the lower end of the shoe bar to move vertically relative to thereof, but prevents any substantial horizontal movement of that end of the bar.

The weight of the shoes 18 is transferred to the supporting lever bar by a 'pivot pin "42 ex r3 tending between the parallel portions 26 and 2! of bar 25 and through the shoe bar 35. This pivot pin 42 is substantially equidistant from the respective pivotal connections of the bars to the roof and to the shoe. It will also be noticed that the pivot pins 29 and 31 are arranged substantially in the same horizontal plane.

It will be understood from the structure thus far described that the sealing ring is supported by a plurality of hangers in which the shoe bars 35 transfer the weight of the ring by means of the connecting pivot 42 to the supporting lever bars 25, and thus to the peripheral rim of the floating roof. This weight is supported by the bars regardless of the position of the roof relative to the side wall of the tank. That is, the roof may move toward or away from the side wall without disturbing the support of the sealing ring or causing it to move vertically with relation to the floating roof.

In order to provide a force for pressing the sealing ring against the tank shell and a force operative to center the roof within the tank, a weight arm 50 is secured to the angular portion 30 of the supporting lever bar. In the present invention the weight arm 50 is pivotally secured by means of pin 5| to the angular portion 30 and is provided with weights 52 which may be varied as desired in the particular installation of the hanger means in a particular floating roof tank. As shown, the lower ends of the angular portion 30 are connected by a bracing member 53 to lend rigidity thereto. The weight arm 50 may be formed of a channel member or a pair of angles secured together to provide a portion 54 extending beyond the pivot pin 5| in the direction of the angular portion 30 for the purpose of bearing against the lower edges of the angular portion 36 to limit downward movement of the Weight arm relative to the lever bar. As shown, the downwardly limited position of the weight arm 55 is substantially 90 to the downwardly extending portion of the bar 25. This restriction, however, does not limit pivotal movement of the weight arm in the direction toward the floating roof from the position shown in solid lines in Fig. 1. Thus as the floating roof nears the bottom of the tank, the weight arm contacts the bottom or other support on the bottom and pivots upwardly to the dotted line position shown in Fig. 1.

When the weight arm is in the dotted line position, the supporting lever bar may rest directly on the weight arm and act as a support for the roof as well as for the sealing ring l1.

While the roof is floating on the stored liquid ll above the bottom of the tank so that the weight arm 50 may pivot downwardly to its predetermined limited position, the weight of the arm is applied to force the shoes tightly against the side wall of the tank. As the roof moves toward the side wall the weight arm is caused to move upwardly, thus increasing the force thereof applied to return the roof to the center of the tank. Conversely the weight arm on the hanger in the diametrically opposite side of the tank would thus be lowered to decrease the force supplied by the weight arm, thus cooperating with the hanger on the opposite side to center the roof.

The angular portion 30 of the bar 25 is generally spaced 3, very short distance from the lower portion of the shoe [8. This position is maintained to allow the sealing ring to ride over irregularities or protrusions in the tank shell and also to allow the sealing ring to project a short 4 distance above the tank shell when the tank is full of liquid, without tipping the sealing ring substantially out of vertical alignment.

The specific hanger illustrated and described above is not necessarily limited to a structure in which the weight arm is pivoted to the angular portion 30, as may be readily understood. The weight arm 50 and angular portion 30 may be made as an integral piece with the pivot pin 5| being placed between the angular portion 30 and the pivot 42 connecting the shoe bar and the supporting bar 25. If desired, the pivot pin 42 may also serve as the pivotal connection between the lower portion or weight arm portion of the lever bar and the supporting portion thereof extending between the pivot 42 and the pivotal connection 29 of bar 25 to the roof. The operation of these alternate constructions is the same as that described and illustrated in detail. Upon lowering of the roof adjacent the bottom of the tank, the weight arm portions contact the bottom of the tank and pivot upwardly with further lowering of the roof. Eventually the roof lowers sufficiently to rest upon the supporting bars 25 which then serve as roof supports. Upon refloating of the roof, the weight arm portions pivot downwardly to their predetermined position at which time they act only in conjunction with the hanger means supporting the sealing ring against the tank side walls and for centering the roof within the tank. The angular portion 35 will be spaced slightly from the sealing ring to limit inward movement of the bottom of the ring when the roof is floating.

While I have shown and described my invention in its preferred embodiment, it is to be understood that it is capable of many modifications. Changes, therefore, in the construction and arrangement may be made without departing from the spirit and scope of the invention as disclosed in the appended claims.

I claim:

1. In a liquid storage tank having a floating roof and one or more shoes adapted to slidably contact the inner side walls of the tank, means for supporting the shoes against the side walls including a supporting lever bar swingably attached to the upper portion of the roof, said lever bar having an angular portion, a portion extending downwardly in the space between the roof and the tank from the point of attachment to the roof to the angular portion and a weight arm portion extending inwardly from said angular portion, said weight arm portion being pivotally secured to said angular portion with stop means preventing downward movement of the weight arm relative to said angular portion beyond a predetermined amount, .and a shoe bar pivotally connected at one end to the upper portion of the shoe and connected to the lower portion of the roof at the other end with a pin and slot connection permitting vertical movement and preventing horizontal movement of said other end with respect to the roof, said shoe bar being pivotally connected intermediate its ends to the downwardly extending portion of said lever bar and being supported thereby.

2. Apparatus of the character described in claim 1 in which said weight arm is inclined downwardly toward the center of the tank from said angular portion while the roofis floating substantially above the bottom of the tank and is pivoted into substantially horizontal position by contact with the tank bottom to support the roof when the roof is in its lowest position.

3. In a liquid storage tank having a floating roof and one or more shoes adapted to slidably contact the inner side walls of the tank, means for supporting the shoes against the side Walls including a supporting lever bar swingably attached to the upper portion of the roof and having an angular portion with a portion extending downwardly from the point of attachment to the roof to the angular portion, a weight arm pivotally secured to the free end of the angular portion and extending inwardly therefrom, stop means preventing swinging movement of said weight arm relative to said angular portion in a.

downward direction only, said stop means maintaining said weight arm elevated from a freely hanging position, a shoe bar pivotally secured to the shoe at its upper end and connected to the roof at its lower end, said connection of said lower end to the roof permitting vertical movement and preventing horizontal movement of said lower end with respect to the roof, and said shoe bar being pivotally connected intermediate its ends to the downwardly extending portion of the supporting lever bar.

4. Apparatus of the character described in claim 3 in which said weight arm is provided with a flat lower surface adapted to rest directly on the bottom of the tank when the roof is in its lowest position in the tank and said supporting lever bar and weight arm support both the roof and the shoe when the roof is in said position.

5. In a liquid storage tank having a floating roof and one or more shoes adapted slidably to contact the side walls of the tank, means for supporting the shoes against the side walls comprising a supporting lever bar pivotally secured to the upper portion of the roof and extending downwardly between the roof and side walls, said lever bar having an angular lower portion positioned adjacent the shoe with the free end thereof terminating slightly below the lower level of the roof, a shoe bar pivotally secured to the upper portion of the shoe and extending downwardly to the lower portion of the roof, said shoe bar being connected to the roof with a pin movable in a vertical slot, said lever bar and shoe bar being pivotally secured together intermediate their ends with said lever bar carrying the weight of the shoe and shoe bar to the roof, and a weight arm pivotally secured to said angular portion and extending inwardly from said angular portion under the roof, said weight arm being limited in pivotal movement between said inwardly extending position and a position against the tank bottom, said lever bar being adapted to support said roof against said weight arm when the roof is in its lowest position.

6. Apparatus of the character described in claim 5 in which said weight arm is maintained 6 in a relative position not substantially more than 90 to said supporting lever bar.

'7. In a liquid storage tank having a floating roof and one or more shoes adapted to slidably contact the inner side walls of the tank, means for supporting the shoes against the side walls including a supporting lever bar swingably attached to the upper portion of the roof, said lever bar having a portion extending downwardly in the space between the roof and the tank from the point of attachment thereof to the roof, a weight arm portion pivotally connected to said lever bar and having a free end normally disposed under said floating roof, stop means at said pivotal connection preventing downward movement of the free end of said weight arm portion beyond a predetermined amount, and a shoe bar pivotally connected at one end to the upper portion of the shoe and connected to the lower portion of the roof at the other end with a pin and slot connection permitting vertical movement and preventing horizontal movement of said other end with respect to the roof, said shoe bar being pivotally connected intermediate its ends to the downwardly extending portion of said lever bar and being supported thereby.

8. In a liquid storage tank having a floating roof and one or more shoes adapted to slidably contact the inner side walls of the tank, means for supporting the shoes against the side walls including a supporting lever bar swingably attached to the upper portion of the roof, said lever bar having a portion extending downwardly in the space between the roof and the tank from the point of attachment thereof to the roof, an angular portion at the lower end of said downwardly extending portion and a weight arm portion extending inwardly from said angular portion, a shoe bar pivotally connected at one end to the upper portion of the shoe and connected to the lower portion of the roof at the other end with a pin and slot connection permitting vertical movement and preventing horizontal movement of said other end with respect to the roof, said shoe bar being pivotally connected intermediate its ends to the downwardly extending portion of said lever bar and being supported thereby, and said supporting lever bar having the lower portion thereof pivoted to said downwardly extending portion with stop means preventing downward movement of the pivoted portion beyond a predetermined amount.

FREDERICK D. MOYER.

References Cited in the file of this patent UNITED STATES PATENTS Number