US1986869A - Tank roof - Google Patents

Description

E. W. WELP Jan. 8, 1935.

TANK ROOF Filed Dec. 7, 1932 fwefilir: Edward W Wfilp,

Patented Jan. 8, 1935 UNITED STATES TANK ROOF Edward W." Welp, Chicago, Ill., assignorto Graver Tank & Mfg. Com, East Chicago, Ind., a corporation of Illinois Application December 7, 1932, Serial No. 646,058

2 Claims. (Cl. 220-26) This invention relates to storage tanks, such as are used for storing oil or gasoline and more particularly to the roofs of such tanks. It has been illustrated as embodied in a floating roof. In the storage of gasoline and other volatile and combustible material, various problems arise. A fixed roof is unsatisfactory not only because of the costly structure necessary to make it self supporting when the tank is only partially full, but also because a large vapor space is left abovethe gasoline, which of course is unsafe on account of the danger of explosion. It is therefore, preferred to use a floating roof which, by its nature, eliminates the major portion of the gas space by resting on the oil.

With floating roofs however, there are the problems of sealing the edges so far as possible without materially affecting the movement of the roof, and without permitting the formation of gas pockets of too large a size in connection with the seal, and of providing sealing means which are not only cheap in construction, but thoroughly dependable in their action.

According to the present invention, these problems are solved by providing on a floating roof of any type, a series of arcuate sealing plates shielded by a watershed, linked together and to the floating roof by flexible sealing strips to form a continuous cover and actuated by means such as a float which is wholly protected from the elements by said watershed and said roof.

With these and various other objects in 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, drawing and claims appended hereto.

' In the drawing, which illustrates an embodiment of the device, and wherein like reference characters are used to designate like parts,

- Figure 1 is a fragmentary plan view of a tank; Figure 2 is a vertical cross-sectional view of the structure of Figure 1 built in accordance with this invention; and

Figure 3 is a detail horizontal sectional view showing particularly the attachment of the outer sealing webs to the shoes, and is a cross-section taken through the line 3 -3 of Figure 2.

Although my invention may take many forms, only one has been chosen for illustration. In this form, the central portion of the roof illustrated in Figure 1 is commonplace and has been shown simply for the purpose of illustration.

The roofmay comprise a main deck 10 which may include any desired frame structure and must of course include a bottom 12 and sides 14 which are fluid-tight to insure their permanently floating. As is the custom, such a deck should also be drained in any suitable manner, as through a flexible or pivoted piping connection within the tank. There may be also a guide roller 16 mounted on the arm 18 secured to the deck and having the purpose of keeping the deck substantially centered within the tank 20. .The arms 18 must of course be sufllciently short to permit free passage of the deck up and down within the tank in spite of any unevenness of the tank walls. All of the structure so far described is old in the art, merely forming the basis for the present invention, or comprising an old element in inventive combinations; it therefore has been shown very diagrammatically and described very briefly.

In order to close the space between the deck sides 14 and the walls of the tank 20,-or in other words to seal the liquid within the tank as nearly as possible, arcuate sealing plates 22 are provided, each of which is secured to an arm 24 in any suitable manner, as by the rivets illustrated. The arm 24 may be provided as at 26 with a bracket 28 which may be secured to the deck 10 in any suitable manner, as by welding. Secured to the inner end of the arm 24 preferably also by welding is a float 30 which for cheapness of construction may comprise a simple cubical container vapor-tight on all of its sides except at its bottom 32 which may be open. It will be readily understood that air or vapor is entrapped within the float 30, and since the float is always completely submerged, the buoyancy thereof is substantially uniform. This buoyancy is transmitted by the lever 24 to thrust the shoes 22 outwardly against the tank wall 20. The shoes 22 are curved in a horizontal plane to fit the curvature of the tank walls, and are curved in a vertical plane sufliciently to prevent their catching on outstanding rivets or joints between plates or other obstructions. The outer surface may be provided with a contact, plate 34 which preferably extends throughout the s'urface of the shoe 22, and if desired may-be made of some noncorrosive metal, or may be coated or covered with a non-corrosive metal, such as brass.

In order to seal the liquid between deck side 14 and shoes 22 from the atmosphere, a flexible sealing cover 36 and flexible sealing strips 38 are provided. The flexible cover 36 may be secured to the shoes 22 by a securing strip 40, riveted to said shoe to seal said cover thereto as shown. It may be secured to the deck side 14 in a similar manner by being clamped down between deck side Q 14 and members 42 which comprise a water-shed.

It is to be understood that the water-shed is preferably made up from a number of segments joined together, although this detail has not been shown. Sealing strips 38 may be secured to adjacent shoes in a similar manner. Thus, as illustrated in Figure 3 they are clamped to the shoes by strips 44 which are riveted in place by rivets 46 which are preferably providedflush heads at their outer ends. The contact plate 34 may be perforated to receive these rivets, or to the extent that assembly, conditions permit, may be attached to the outside of the rivets. The operation of the structure hardly nee explanation. As the deck is raised or lowered by the change in the level of the oil, the shoes 22 are likewise raised and lowered. In any given position the shoe 22 is pressed by the buoyancy of the float against the tank wall 20. When the deck is raised or lowered, if the shoe should strike a rivet or other projection it would swing inwardly toward the deck side 14. As soon as the projection is passed, the buoyancy of the float thrusts the shoe outwardly into its normal sealing position. The surface exposed for evaporation, it is evident with the structure shown, has

been reduced to a minimum, while the volume of the gas pocket is quite low. The only surface exposed to the atmosphere would be that between the shoes 22 and the wall 20. Inasmuch as all of the moving parts of the seal are protected from the weather, either by being submerged in the liquid or by being located below the watershed 42, the structure of this invention is unusually reliable.

It is to be understood that many other embodiments of the invention, including some in improved form, will be apparent, and in the course of time more will be devised by those skilled in the art. It is not desired that this invention be limited to the details described, for its scope includes all such forms or improvements as come within the spirit of the following claims, construed as broadly as the prior art will permit.

What is claimed is:

l. A floating roof for tanks including: a floating deck, a plurality of levers pivoted to said deck, a sealing shoe connected to the outer end of each lever, means acting through said levers for urging said sealing shoes outwardly toward the wall of the tank, and rollers for limiting the lateral movement of said deck; all the surfaces of said structure which contact with each other frictionally being located below the lowest normal level of liquid with respect to said root when said roof is floating, whereby said frictional parts are constantly lubricated by the stored liquid.

2. A floating roof for tanks including: a floating deck, a plurality of levers pivoted to said deck, a sealing shoe connected to the outer end of each lever, means acting through said levers for urging said sealing shoes outwardly toward the wall of the tank, and means for limiting the lateral movement of said deck; all the surfaces of said structure which contact with each other frictionally due to the inward and outward movement of said sealing shoes being located below the lowest normal level of liquid with respect to said roof when said roof is floating, whereby said frictional parts are constantly lubricated by the stored liquid.

EDWARD W. WELP.

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