US2897998A

US2897998A - Floating roof seal arrangement

Info

Publication number: US2897998A
Application number: US604909A
Authority: US
Inventors: Reign C Ulm
Original assignee: Union Tank Car Co
Current assignee: Union Tank Car Co
Priority date: 1956-08-20
Filing date: 1956-08-20
Publication date: 1959-08-04
Anticipated expiration: 1976-08-04

Description

Aug. 4, 1959 c. ULM

FLOATING ROOF SEAL ARRANGEMENT 2 Sheets-Sheet 1 Filed Aug. 20, 1956 g- 1959 R. c. ULM

91.0mm; ROOF SEAL ARRANGEMENT 2 Sheets-Sheet 2 Filed Aug. 20, 1956 IN V EN TOR FLOATING ROOF SEAL ARRANGEMENT Application August 20, 1956, Serial No. 604,909

4 Claims. (Cl. 22026) The invention relates to a floating roof for use in field storage tank arrangements and particularly to a novel seal design arranged to seal the space between the periphery of the roof and the tank shell.

As is well known to those skilled in the art, floating roof field storage tanks have been used tostore a variety of products. Conventional arrangements of this nature are frequently used in the storage of petroleum products such as raw crude, gasoline and the like. On occasions it becomes desirable to use this type of structure to store certain chemicals which must be protected against evaporation and contamination. With this type of product positive sealing becomes important to prevent product vapor escape and it is additionally necessary that the seal be, from a practical standpoint, impervious to entrance of water and other foreign matter into the product.

Accordingly, it is a primary object of the invention to provide a novel arrangement to positively seal the peripheral space between the floating roof and the tank shell.

It is a further object of the invention to provide an arrangement of the type described that is particularly useful in field storage tanks wherein storage of certain chemical products is contemplated.

Particularly, the invention comprehends a floating roof and a metallic shoe peripherally disposed therearound and in engagement with the internal surface of the tank shell, generally horizontally adjacent the roof. Hangers, preferably of the spring type, may have their lower ends attached to the roof and their upper ends pivoted to the shoe at a plurality of points to provide resilient support to the latter. A molding arrangement may be continuously mounted upon the upper edge of the shoe in such a manner so as to space adjacent portions of the latter from the tank shell and to also provide a line of pressure concentration. The molding is provided with a feathered lip or scrapingedge which engages the internal shell surface to wipe same clean in addition to providing a positive seal between the shoe and the tank shell. Further, a plurality of spring-like flaps may be mounted on the shoe to flexibly engage the internal surface of the tank shell above the molding and aid in the seal function. Desirably, a springlike pusher arrangement is interposed between and in pressure engagement with the roof and the shoe and is preferably arranged to engage the shoe in an area adjacent the molding. A conventional primary seal fabric may be continuously secured to the shoe and the roof to further close the space therebetween.

These and other objects of the invention will become apparent in the course of the following description and from an examination of the concerned drawings, wherein:

Figure 1 is a fragmentary cross-sectional view illustrat- 65 ing the arrangement,

Figure 2 is a fragmentary detailed view of a portionof the arrangement illustrated in Figure 1,

Figure 3 is a fragmentary side elevational view of the structure shown in Figure 2 with the tank shell removed, and

States Patent O Figure 4 is a fragmentary detailed view of the pressure molding utilized in the invention.

Describing the invention in detail and directing attention to Figure 1, it will be understood that the field stor- 5 age tank may comprise a conventional cylindrical shell 2 arranged to surround a floating roof, fragmentarily illustrated at 4. A shoe 6, preferably composed of flexible metallic segments is arranged to surround the roof 4 and engage the internal surface of the shell 2. A hanger 8, preferably of the resilient spring type, may have its lower end pivoted as at 10 to the roof 4, and its upper end pivoted as at 12 to a bracket 14 secured to the shoe 6, whereby the hanger supports that portion of the shoe there adjacent. It will be understood by those skilled in the 15 art that a plurality of hangers 8 are preferably arranged around the roof to offer continuous support to the shoe. Adjacent the upper edge of the shoe6, a seal fabric 16, of flexible material, is provided with an edge secured to the inner surface of the shoe 6 and has its other edge secured to the roof 4. The fabric 16 is, of course, peripherally arranged around the roof 4 and therefore provides a continuous cover for the space between the shoe and roof.

The upper extremity of the shoe 6 has a seal pressure molding member 20 continuously mounted thereon 5 around the periphery of the tank. The member 20 is provided with a portion 22 which is interposed between the upper edge and shoe 6 and the tank shell causing said upper portion of the shoe 6 to be spaced slightly from the inner surface of the shell. In the preferred embodiment the member 20 additionally is provided with a scraping edge or lip 24 which engages the inner surface of the shell and acts to scrap any residue therefrom upon upward movement of the roof in the tank. Also, the shoe 6 may carry a plurality of horizontally arranged clamping channels 28 secured thereto adjacent its upper edge. The clamping channels carry a plurality of

support pins

30, 30 which serve as supporting members for two vertically spaced layers of

flaps

32, 32.

Considering Figure 3, it will be seen that the pins 30 are secured to the flaps, such as by soldering, as at 34, or

any other convenient method. The upper and lower layers of the flaps 32 are horizontally staggered to aid in the sealing and scraping function hereinafter described. It will be understood that the flaps 32 are preferably 'made of thin rather spring-like flexible material and that in their assembled condition, shown in Figures 1 and 2, are in pressured engagement with the internal surface of the tank 2, so as to be installed in a flexed condition.

Directing attention to Figure 1, it will be seen that spring pusher means 38 may be mounted in such a manner as to be interposed and in pressured engagement with an -abutment 40 on the roof 4 and the. upper portion of the shoe 6. Retaining lugs 42 and -44 may be employed to position the spring 38. Of course, a plurality of such spring pushers are peripherally disposed around the roof. It will be understood by those skilled in the art that the spring pushers 38 perform a multiple function, namely, the maintenance of sealing engagement with the internal surface of the tank and serves to urge the floating roof 4 to a central position in the tank. In the preferred embodiment, each spring pusher 38 engages the adjacent shoe 6 at a point in the vicinity of the molding 20, and, because the portion 22 of the molding 2t slightly spaces the upper segment of the metallic shoe 6 from the shell, it will be understood that the force or pressure exerted by the pusher 38 tends to be concentrated in the area of engagement between the molding 20 and the internal surface of the shell. Additionally, location of the pushers 38 at this point aids in maintaining the flaps 32 in proper engagement with the inner shell surface. 7

Considering Figure 4, it will be seen that the pressure molding 20 in its nonmounted condition has the lip or edge reo f rm d outwa ly f e q iq 22. In the assembled condition, the action of the pusher 38 moves the lip 24 to a vertical position, as is shown irrFigurev 2, 'with the result that the lip 24 is stressed so that it will tend to flex outwardly should thefpressure of the spring pusher 38, become dissipated due to roof movement or the like. It will be remembered that the flaps 32 are also in a flexed condition when normally engaging the shell 2 under the action of the spring 38, Again should the pressure of the spring pusher 38 become dissipated due to roof movement, the inherent flexibility of the flaps 32 tends to maintain the seal contact with the inner tank shell. These features are important in that the roof, under the action of wind orother forces or 'due to irregularities in the shelLon some occasions may become so uncentered in the tank that loss of pressure from the pushers 38 on certain portions of the tank could result, and, in this eventthe flexibility-of the flaps 32 and lip 24, tends to maintain sealing contact with the shell.

It will thus be understood that the disclosed arrangernent has particular utility in preventing rain water or other foreign material on the tank shell from entering -the product. The arrangement carries this material in wardly toward the roof 4 by urging same downwardly over the flaps 32, the fabric 16 and then to the floating roof. Additionally should certain material or foreign matter pass under the flaps 32, the seal molding 20 will also engage same and again force it inwardly toward the roof, as above descirbed. Furthermore, both the flaps 32 and the molding 20 serve to scrape the tank shell during upward movement of the roof and remove foreign matter collected thereon thus preventing entrance of the same into the product.

Thus it will be seen that I have provided a novel seal arrangement which offers positive and eifective sealing of space between a floating roof and the tank shell, and is especially effective to prevent entrance of foreign material into the product stored in the tank.

The invention disclosed is by way of illustration'and not limitation and may be subject to various modifications without departing from the spirit thereof or the scope of the appended claims.

What is claimed is:

'1. In a seal arrangement for a storage tank comprising a cylindrical shell with a roof arranged to float on product in the shell, a rim peripherally arranged around the roof and spaced from the shell, a flexible shoe surrounding the roof and supported from said rim, a flexible fabric peripherally arranged around the roof and having its opposed edges secured to the upper edge of the rim and adjacent the upper edge ofthe shoe, respectively, to substantially seal the space between the rim and the shell, secondary seal means comprising a substantially continuously non-metallic element secured to the top of the shoe and having at least a portion thereof interposed between the shoe and the shell, said element having an upwardly directed scraping edge flexibly contacting the shell, flap means mounted on the shoe adjacent the upper edge thereof and extending upwardly above the secondary seal means to present upwardly directed edge means flexibly engaging the shell, and coiled spring means interposed between and in pressured engagement with the roof and the shoe and engaging the shoe at points immediately adjacent the upper edge thereof.

2. In a seal arragnment for a storage tank having a shell with a floating roof therein, said roof being peripherally spaced from the shell, a flexible shoe surrounding the roof and supported therefrom and engaging the shell, a sealing fabric secured to the roof and shoe to close the space therebetween, flap means secured to the upper edge of the shoe and flexibly engaging the shell, said flap means comprising relatively thin flexible plates connected at their lower edges to the shoe and extending upwardly above the shoe and outwardly into flexible pressured engagement with the shell surface above said shoe, said plates having an upwardly facing edge during all roof movement whereby said edge is operative to scrape said shell surface during upward movement of the roof, secondary'seal means continuously secured to the top edge of the shoe and flexibly engaging the shell surface below the area of engagement between said surface and said plates, said last mentioned means including a scraping edge engaging said shell surface, said last mentioned scraping edge facing upwardly during all roof movements, and spring means interposed between and in pressured engagement with the roof and the shoe.

3. A seal arrangement according to claim 2, wherein said secondary seal means comprises a substantially conuous non-metallic element secured to the top of the shoe and having at least a portion thereof interposed between said shoe and said shell whereby and upper portion of the shoe is slightly spaced from the shell, and wherein said plates are metallic and comprise two layers, said layers being in vertical spaced relation to each other.

4. A seal arangement according to claim 3, wherein said spring means comprises coil springs arranged to engage the shoe at points immediately adjacent the top edge thereof.

References Cited in the file of this patent UNITED STATES PATENTS 1,597,046 Bohnhardt Aug. 24, 1926 1,668,792 Wiggins May 8, 1928 1,900,904 Berger Mar. 14, 1933 2,427,171 Wiggins Sept. 9, 1947 2,459,178 'Moyer Ian. 18, 1949 2,568,728 Goldsby et al. Sept. 25, 1951 2,685,503 Knecht Aug. 3, 1954