US2884156A

US2884156A - Floating roof seals

Info

Publication number: US2884156A
Application number: US561844A
Authority: US
Inventors: Arthur H Graham; Staley Saunders Skeen
Original assignee: TANK SERVICE AND CONSTRUCTION
Current assignee: TANK SERVICE AND CONSTRUCTION; TANK SERVICE AND CONSTRUCTION Co
Priority date: 1956-01-27
Filing date: 1956-01-27
Publication date: 1959-04-28
Anticipated expiration: 1976-04-28

Description

A. H. GRAHAM ET AL 2,884,156

FLOATING ROOF SEALS A ril 28, 1959 I Sheets-Sheet 1 Filed Jan. 27, 1956 "Ar/bur /7. Graham MJ M am. m M v N J 6, g M Y, v U B April 28; 1959 A. HNGRAHAM ET AL FLoATIN ROOF SEALS 3 Sheets-Sheet 2 Filed Jan. 2'7, 1956 Jauna e/u J. J/a/ey INVENTORS BY V 2010M gafww April 28, 1959 -A. H. GRAHAM ET AL 2,884,156

' FLOATING ROOF SEALS Filed Jan. 27; 1956- 3 Sheets-Sheet 5 nu E1 i WN "i 5 INVENTORJ' FLOATING ROOF SEALS Arthur H. Graham, 'Bellaire, and Saunders Skeen Staley, Dallas, Tex.; said Graham assignor of one-fourth to Tank Service and Construction Company, a corporation of Texas Application.lanuary 27, 1956, Serial No. 561,844

- 1 Claim. Y Cl. 220-26) This inventionrelates to new and in floating roof seals.

This application is a continuation-in-part of our copending'applicationSerial No. 173,762, filed July 14, 1950 and now Patent No. 2,740,549. I

One object of the present invention is to provide an improved tank roof seal assembly wherein flexible sealing elements, as distinguished from metallic shoe members or the like, engage the tank wall to perform the sealing function, whereby the seal is particularly adaptable for use with bolted or riveted tanks which have an irregular inner surface.

An important object is to provide an improved tank sealing assembly having flexible or resilient sealing elements inengagement with the tank wall, together with means associated with the assembly for assuring proper travel of the assembly within the tank upon a change in the liquid level in the tank, whereby binding or improper movement of the assembly is prevented; said means also functioning to properly locate the assembly within'the tank to assure efiicient sealing at all positions of the assembly within the tank.

Another object is to provide atank roof sealing assembly having a lower sealing element and an upper sealing element, both of which are flexible and in sealing engagement with the tank wall to prevent escape of vapors upwardly from the tank; the upper element also functioning to seal the tank interior against external causes of turbulence, whereby more efiicient sealing 'is produced.

Still another object 'is to provide a floating roof seal for tanks wherein the flexible sealing elements are carried ,by arcuate supports which are urged outwardly toward the tank wall by spring means, together with spacer rollers or elements which engage the tank wall to properly locate, the sealing elements to thereby assure efficient sealing at all times. a

A further object is to provide an improved mounting forthe flexible sealing elements which includes a simple sealing'means between the vertical abutting edges of the arcuate supports which carry the elements, whereby said supports may undergo limited movement relative to each other without disturbing the effectiveness of the sealing means at their abutting. edges.

The construction designed to carry out the invention will be hereinafter described, together with other features thereof.

The invention will be more readily understood from a readingof the following specification and by reference to the accompanying drawings forming a part thereof, wherein an example of the invention is shown and where- Figure l is an isometric view of a tank having the improved fioating roof assembly, constructed in accordance with the invention, mounted therein;

Figure 2 is an enlarged vertical, sectional view illustrating the sealing elements of the assembly in contact withthetank wall;

useful improvements 2,884,] 56 Patented Apr. 28, 959

Figure 3 is a horizontal, cross-sectional view taken on the line 3--3 of Figure 2; V

Figure 4 is a partial isometric view illustrating the sealing means between the adjacent orabuttingedg'es of the supports; s

Figure 5 is a horizontal, cross-sectional view taken on the line 5-5 of Figure 4; and

Figure '6 is an enlarged sectional detail of a modification of the spacer and guide means of the assembly.

In the drawings the'numeral 10 designates the usual storage tank within "which liquids such as petroleum products are stored. The tank is illustrated as the usual riveted or bolted'tank which is constructed'of aplurality of plates suitably bolted or riveted together. The plates 10a which are secured togetherto form the tank have their edges in overlapping'relat'ionship as illustrated in Figure 2 and rivets 11' are shown as securing these overlapping edges together. Obviously, due to the construction, the edge of the innermost plate forms a' shoulder or olfset indicated at 12 in Figure '2 along ,the internal wall of the tank; thus the internal wall of bolted orriveted tanks 'isnormally irregular and, of course, the rivet or bolt heads add to this irregularity.

The improved seal. for sealing between the usual floating roof 13 of the tank is illustrated in Figures 2 to 5. The tank roof 13 is disposed Within the tank and is a generally cylindrical or circularshape having its side Walls or skirt 13a'spacedlsome distance from the inner surface S of the tank wall. The seal which is disclosed herein is for the purpose of efliciently sealing off the annularspa'ce between the inner surface S of the tank wall and the outer surface of the skirt portion or side wall 13a of the tank roof13. As is well known in" tanks of this character, thereof '13 is floating and rises and falls with the liquid level within the tank. I

In carrying out the" present .invention a plurality of arcuate supports 14'are provided and each support is, in fact, an I-beam having an upper flange '15, a lower flange 16, and a connecting web 17. Each support 14 is arcuate in plan and each I-beam has its vertical edge adjacent the vertical edge of the abutting I-beamsupport.

For sealing between the vertical abutting or adjacent,

edges of the arcuate support members or sections, each end of the upper flange 15 of each I-beam is formed with a recess 18 (Figure 4)','while the lower flange 16 of the I-beam is providedwith a similar'recess 19. A tubular sealing element 20, which is constructed of rubber, syntheticrubber or other material impervious to petroleum products, is disposed between the abutting vertical edges of adjacent arcuate support members, said seal element being confined within substantially semi-circular pipes 18, and 19' disposed in the

recesses

18 and 19, respectively,

of the flanges 15 and16. Such pipes 18' and 19' are welded or. otherwise united to the

flanges

15 and 16 of the

recesses

18 and 19, respectively," and also to the web 17. It is evident that since the sealing members 20 are tubular in form, thejadjacent'arcuate supports may undergo independent movement with respect to each other without disturbing the seal between the tubular element 20 andthe vertical surfaces of the arcuate members or sections. p v

Each arcuate section is resiliently supported by an elongate flat leaf spring 21, which as shownin Figures 2 and 3, has its central portion suitably clamped by a clamping plate 22 to a'supporting angle 23, the latter extending upwardly from the tank roof 13. Each.

the arcuate support member or section to which it is attached outwardly in a radial direction toward the inner surface of the tank wall. It is evident that due to the pivotal connections between the ends of the leaf spring and the arcuate section, the radial movement of the section is possible without interfering with the spring action. To control the distance between each arcuate section 14 and the inner wall surface, the spacer or guide roller or wheel 29 is provided. This roller is adapted to engage or ride upon the inner wall surface of the tank. Each guide roller is mounted on a transverse pin 30 which is carried by a bracket 31, the latter being bolted at 32 to the web 17 of the I-beam, which web is formed with a suitable opening 17a, through which the support bracket 31 extends. Since the outer periphery of the roller engages the inner wall surface, it is obvious that the diameter of the roller or wheel 29 will control the spacing between the arcuate section and the tank wall. Although any number of rollers 29 may be mounted on each section, it has been found preferable to provide two rollers for each section as is illustrated in Figure 3. If desired the roller 29 may have teeth 29a to increase the frictional engagement of the roller with the tank wall; by providing these teeth, the roller will, in effect, walk up and down the wall of the tank as the roof undergoes vertical movement and will thereby assure that the roof will move properly within the tank. By varying the diameter of the roller the spacing between the I-beam support and the tank wall may be controlled.

For sealing the annular space a flexible sealing element 32 is provided. This element may be constructed of synthetic rubber or other material which is impervious to petroleum products and is generally in the form of an annular ring. The inner peripheral edge of the sealing element 32 is clamped by means of a ring 33 and bolts 44 to the tank roof. The element 32 underlies the lower flange 16 of each of the arcuate I-beam supports and is suitably clamped thereto by a clamping member 35 and bolts 36. It is noted that the sealing element 32 closes the lower end of the tubular sealing elements 20 which are disposed between the vertical adjacent edges of the adjacent arcuate supports. The outer periphery of the sealing element is adapted to engage the inner wall surface S of the tank and to seal therewith. It is obvious that as the tank roof 13 moves vertically within the tank the outer periphery of the sealing element 32 remains in constant contact with the inner wall surface S of the tank and maintains a seal therewith. Because this outer peripheral portion is extremely flexible, it is evident that the same may readily move over the shoulders 12 formed between the plates of the tank and may also move over the rivet heads or, if bolts are used, over the bolt heads without affecting the sealing efliciency.

An upper wiper element or weather shield 37 has its inner peripheral edge clamped by members 38 and bolts 39 to the upper surface of the flange 15 of the I-beam supports. This member overlies the flange 15 and functions to close the upper ends of the tubular sealing elements 20, which are located between adjacent edges of the various arcuate supports or I-beams. The outer periphery of the sealing element 37 is also in engagement with the tank wall S and this element is also extremely flexible so as to maintain constant contact with the wall surface. The wiper 37 may readily move over the rivet heads as well as over the shoulders 12 formed between tank plates without affecting the. seal. The upper element 37 functions as a shield or member which firmly seals the interior of the tank against conditions which might occur exteriorly thereof and which might otherwise affect the main sealing element 32.

The operation of the assembly is believed evident from the foregoing. The flexible sealing element 32 is actually secured to the tank roof which will, of course,

move upwardly and downwardly within the tank in accordance with the liquid level. The outer portion of the sealing element 32 is actually supported by the arcuate I-beam supports, which, as explained, are disposed within the interior of the tank. The I-beam supports are flexibly mounted by means of the elongate fiat springs 21, and the position of the supports, and therefore the position of the sealing element 32, are controlled by the size of the spacer and guide rollers 29. As the tank roof moves vertically within the tank, the rollers 29 will move along the inner surface S of the tank wall and will not only function as a spacer to maintain the desired pressure outwardly on the I-beam but will also assist in assuring that the tank roof may move without binding within the tank. The flexible sealing element 32 as well as the wiper seal 37 will have their peripheral edges in flexible sealing contact with the wall. Because of their flexibility, the

elements

32 and 37 may readily ride over the shoulders, rivet heads or other irregularities in the tank wall without affecting sealing efficiency. It might be noted that the assembly completely eliminates the provision of any metallic shoes such as have been in common use in forming a seal with the inner wall of a tank.

It has been pointed out that the rollers 29 which function to properly space the I-bearn supports within the tank may have the teeth 29a thereon to assist in the vertical movement of the roof assembly. However, it is not essential that these rollers have an irregular external surface, and in Figure 6 a roller 29b, having a smooth periphery, is illustrated. The roller will freely roll upon its pivot with its periphery in engagement with the tank wall and will function at all times to control the spacing of the I-beam supports, as they are urged outwardly by the flat springs. In this manner the peripheral sealing edge of the main sealing element 32 as Well as the sealing edge of the wiper element 37 are maintained in desired sealing contact with the tank wall.

Since the sealing

elements

32 and 37 are non-metallic and the rollers 29 are ordinarily non-metallic, the parts of the improved seal assembly of this invention which contact the steel tank are non-metallic, and therefore there is no danger of galvanic action between the steel tank and the metallic parts of the seal assembly; for this reason, the parts of the seal assembly which do not contact the steel tank can be made of various corrosionresistant materials such as plastic, stainless steel, and aluminum.

It should be pointed out that the seal assembly of this invention can be used in lined tanks such as tanks lined with Gunnite or other corrosion-resistant materials.

The foregoing disclosure and description of the invention is illustrative and explanatory thereof, and various changes in the size, shape and materials, as well as in the details of the illustrated construction may be made, within the scope of the appended claim, without departin from the spirit of the invention. 1

We claim:

The combination with a floating roof storage tank having an upright cylindrical shell constructed of connected plates and also having a buoyant roof vertically movable in the shell, which roof has an annular wall surface of a lesser diameter than the shell, of a sealing assembly for sealing the annular space between the roof and shell and including, an annular support composed of a plurality of arcuate sections with the vertical edges of adjacent sections in abutting relationship, a flexible leaf spring for each arcuate section, each spring having its central portion attached to the roof and having its ends connected to the arcuate sections with which it is associated, said spring exerting a pressure radially outwardly upon the section, an annular flexible sealing element having its inner peripheral portion secured to the roof and its outer peripheral portion engaged with the tank wall,

means for securing the arcuate sections of the annular support to the intermediate portion of the sealing element, whereby said arcuate sections which are urged radially outwardly by their respective springs maintain the sealing element in contact with the tank wall, the 6 abutting vertical surfaces of adjacent sections of the annular support being formed with complementary recesses, a tubular sealing member confined within said recesses and sealing the vertical space between the abutting surfaces of adjacent sections, the lower open end of said tubular sealing member being closed by the annular flexible sealing element which underlies the same, and an upper wire seal secured to the sections of the annular support and having its outer peripheral portion in sealing engagement with the tank wall, said upper wiper seal overlying the tubular sealing members to close the upper end thereof.

References Cited in the file of this patent UNITED STATES PATENTS 1,514,116 Wiggins Nov. 4, 1924 1,900,904 Berger Mar. 14, 1933 2,740,549 Graham et al. Apr. 3, 1956 FOREIGN PATENTS 487,774 Great Britain June 24, 1938