US2537987A

US2537987A - Support for a seal for floating roofs

Info

Publication number: US2537987A
Application number: US637017A
Authority: US
Inventors: Fred L Goldsby; Clifford M Orr
Original assignee: Chicago Bridge and Iron Co
Current assignee: Chicago Bridge and Iron Co
Priority date: 1945-12-22
Filing date: 1945-12-22
Publication date: 1951-01-16
Anticipated expiration: 1968-01-16
Also published as: ES175183A1

Description

Jan. 16, 1951 F. 1 GoLDsBY ETAL SUPPORT FOR A SEAL FOR FLOATING ROOFS 2 Sheets-Sheet l Filed Dec. 22, 1945 x/ w ad.,

i MLM Jan. 16, 1951 F. 1 GoLDsBY ET A1.

SUPPORT FOR A SEAL FOR FLOATING ROOFS 2 Sheets-Sheet 2 Filed D60. 22, 1945 l HI) gym n g fig??- rmnied ne. 1e, 1951 2,537,987 SUPPORT FOR A SEAL FOB I'LOATING BOOFS Fred L. Goldlby and Cliord M. n', Chicago, lll.,

aseignora to Chicago Bridge Iron Company, a corporation of Illinois Application December 22, 1945, Serial No. 837,017

3 Claims.

1 This invention relates to a floating roof tank, and particularly to a seal for sealing the area between the iioating roof and the shell of the tank.

Floating rcoi' tanks are generally used for the storage oi' volatile liquids where the roof floats on top of the liquid. There is ordinarily an annular area between the edge of the floating roof and the shell of the tank. In order to avoid evaporation losses and to prevent contamination of the contents of the tank by dirt, rain water, and the like, it is necessary that a sealing means be provided, sealing o this area. Various types of sealing means have been proposed in the past but many of these have been unsatisfactory because of excess weight, bulk, and the like, and many have been diilicult to install and maintain.

A new type sealing means has been developed that employs a flexible sealing ring to contact the shell of the tank with hanger means to support the ringr in sealing contact with the shell. The new sealing ring is so constructed that it readily slides up and down the tank shell, as the roof rises and falls, and is made quite ilexible so as to follow the contour of the shell if the shell should get out of round. The new hanger means supports the sealing ring in position and provides outward pressure to hold the ring against the shell at all times. The hanger means is preferably rotatable so that sideways shifting of the ring may be accommodated. There is also preferably provided means tending to return the hanger means to its original position when the sealing ring has shifted from its normal position.

One of the chief advantages of the new sealing ring is that it provides very close contact with the shell of the tank, and this contact is maintained when the ring is supported at spaced points.

The invention will be described as related to the embodiment set out in the accompanying drawings. Of the drawings Fig. l is a fragmentary plan view of a oating roof tank embodying the invention; Fig. 2 is a vertical section taken along line 2 2 of Fig. l; Fig 3 is a horizontal section showing one curvature arrangement of the sealing.. ring `when there is no outward pressure applied; Fig. 4 is vertical sections taken along line 4-4 of Fig. 3; Figs. 5 to 8 inclusive illustrate individual steps of a preferred method of forming flexures in the new sealing ring and Fig. 9 is a horizontal section taken along line 9-9 of Fig. 2.

The floating roof tank shown in the accom' Bullying drawings comprises a shell Il and a 2 floating roof il therein. The space between the edge of the floating roof and the shell of the tank is provided with a sealing means to prevent evaporation and contamination of the storedl liquid.

The sealing means shown comprises an annular sealing ring il contacting the inner surface oi' the shell III and supported by hanger means Il mounted around the edge of the iloating roof Il. The annular sealing ring I2 is provided with spaced vertical ilexures Il extending between top il and bottom i8 marginal areas.' These marginal areas are preferably bent back from the vertical and away from the shell in order vto permit the sealing ring to pass over raised sections on the inner surface of the shell.

The fiexures i4 are formed in the sealing ring I2, which is preferably made of sheet metal, and they extend away from the body portion of the lsealing ring. The flexures have the form oi loops formed in the sheet metal with inner portions l1 adjacent each other in order to allow for expansion and contraction of the sealing ring. The flexures may be generally rounded, as indicated. These iiexures not only permit expansion and contraction of the ring, but also permit the ring to bend easily. One method of making the ilexures is shown in Figs. 5 to 8 inclusive. In this method a cut-out portion I9 is formed at one edge of the ring. A second similar cut-out portion is formed on the opposite edge of the ring and opposite the first portion. A third cut-out portion 20 is formed extending from the inner end of the first portion, and -a fourth cut-out portion similar to the third is formed adjacent the other edge of the ring. The third and fourth cut-out portions have one edge 2| substantially parallel to -its edge of the ring, and have another edge 22 of arcuate shape with the arc extending away from its edge of the ring. The fourth cut- 'out portion is formed in the same manner. The

ilexure il is formed by bringing the opposite ends of the third and fourth cut-out portions adjacent each other to form a fold. The overlapping

edges

23 and 24 adjacent the first and second cut-out portions are left free so as to be slidable relative to each other. Thismethod forms a ilexure il having top 25 and bottom 2l edges sloped toward each other at an acute angle to the main body portion of the ring. It is preferred that the top and bottom ends be thusly sloped, although such construction is not absolutely necessary.

Any type oi hanger means desired may be used to support the new sealing ring. The hanger means shown comprises a T bar Il extending between adjacent exures I4 and attached to the sealing ring I2 by means of short brackets 26. The T bar 21 is loosely held by the brackets 28 in order to permit bending of the section 29 of the sealing ring between adjacent iiexures I4. This loose connection may be provided by slots 30 provided in the brackets 28 and engaging studs 3l in the ends of the T bar. Y

The horizontal portion 32 of the T bar 21 extends toward the floating roof. A substantially horizontal pipe 33 is provided having a yoke end 3d with one leg of the yoke above and the other leg below the horizontal portion. A threaded bolt IE5 is loosely held in the yoke 3d and engages threads in the horizontal portion 32. The bolt S5 extends above the yoke 3ft, and a spring 3E is located between the upper end ci the bolt and the top surface of the upper yoke leg. There is also provided a second pipe 3l of larger diameter than the rst pipe 33, and through which the first pipe extends. The first pipe 33 is provided with a roller 33 held in top and bottom slots in the rst pipe 3E and mounted by means of pin for rolling contact with the inside surface oi' the second pipe 3l. pipe 33, opposite the yoke 34, there is located a cap 4I closing this end of the pipe. On the corresponding end of the second pipe 31 there is located an annular cap 42 having a hole 43 therein through which the rst pipe 33 extends. The hole 43 is of such size that the cap 4i on the end of the first pipe will contact the annular cap 42 when the rst pipe has been extended its full `distance toward the shell of the tank. Between the annular cap 42 and the roller 38 there is provided an annular collar 44 on the first pipe 33. This collar is of such diameter that it slides freely within the second pipe 3l. Between the annular cap 42 and the collar 44 there is provided a spring 45 normally urging the first pipe 33 toward the shell of the tank.

In order to support the second pipe 31 and the iirst pipe 33 there is provided a third pipe 46, attached near the front end of the second pipe 3l and extending downwardly therefrom. rlhis third pipe abuts the 'edges of a hole 4B in a horizontal base plate 41. The third pipe 46 is rotatably held concentric to the hole 48 by providing a smaller concentric pipe 49 extending through the hole 48 with the concentric pipe being attached to the third pipe as by welding 50. On the bottom of the concentric pipe 49 there are located three lugs 5I in order to hold the assembly in place. In assembling the structure the lugs 5I may be inserted through cut-out portions 52 at the edge of the hole 48. The lugs 5I and cut-out portions 52 are arranged so that they wil1 not coincide when the hanger means is in use.

The base plate 41 is supported on vertical threaded posts 53 mounted on the deck `of the iloating roof. The base plate is held on the post by means of nuts 54'on either side of the base plate so that the position of the plate may be easily regulated. y

In order to take up some of the load of the sealing ring I2 a spring 55 is provided extending substantially vertically from the rear of the base plate 41 to the second pipe 31. The spring is attached to the base plate by means of a hole 56 at the rear of the plate and is attached to the pipe 31 -by means of a downwardly extending eye 51. Any type sealing means may be provided between the sealing ring I2 and the edge of the floating roof II. As shown, this. sealing means comprises a flexible sealing member 58 made of fabric im- On the end of the first pregnated with a flexible impervious material. The sealing member 58 is attached to the sealing ring ,by means of bolts 58 extending through a washer bar 60 and the sealing ring I2. The roo! edge of the sealing member 531s attached to the rooi' by means of hooks 6I holding wedges l2 pressing against a circular rod 83 in contact with the roof edge ci the sealing member 58. Any other means of fastening may be used if desired.

The sealing ring l2 may also be provided with any type of secondary seal (not shown) for sealing any areas between the shell I0 and the sealing ring it.

The spring 38 around the top end of bolt 2l is provided so that each oi the hanger means Il will carry its proportionate share of the load of the sealing ring. The bolt 35 serves to adjust the position of the T'bar 2 with respect to the first pipe 33 and may be used to even up the load on all hangers. The spring 46 around the first pipe 33 serves to hold the sealing ring tightly against the shell it?. The spring 55 between the base plate 4i and the second pipe 31 applies a vertical load to the inner end of the second pipe and serves to at least partially balance the load of the sealing ring. If the sealing ring should move to one side of its normal position the spring 55 also applies a force tending to restore the pipe 3l to a radial position. The spring 55 reduces the bending moment at the base plate 41 and helps to prevent breakage of the hanger. The spring 55 is of such strength that the moment when the roof is moving up is approximately the same but oi opposite sign as the moment when the roof moves down. This is accomplished by providing a spring that would resist a load equal to the weight of the sealing ring. This of course is not essential, and the spring load could be made such that the moment at the connection at the base plate 41 would always be of the same sign, but of varying magnitude. The spring, or any similar reinforcement, may be eliminated if desired and the connection at the base plate be made strong enough to withstand all force to which it would be subjected.

The base plate 41 is mounted on the threaded posts 53 so that each plate can be levelled and adjusted vertically. For propel` operation it is preferred that all the hanger means be in a substantially horizontal plane. Since the top of the floating roof may vary somewhat from a hori-i zontal plane the vertical adjustment is required. Since the pipe 31 is mounted for rotational movement in a horizontal plane it is necessary that the base plate be kept approximately level. and thus a minimum of three posts 53 is required.

The sealing ring is preferably constructed so that portions of the ring between adjacent ilexures should have radii of curvature, when unrestrained, diering from the radius of the shell. The hanger means will then be arranged to press against the ring at points substantially adjacent where the distance between the shell and the ring tends to be the greatest. By pressing at these points adequate contact may be maintained over substantially the entire surface of the sealing ring. This principle of construction is shown in Fig. 3, where the radius of the portion 23 is less than the radius of the shell and the hanger means press against the ends of the portion 23. If desired, however, the sealing ring may be of substantially the same radius of curvature as the radius of the shell. Although the sealing means has been shown with the hanger pressing against the shoe at areas between 'ilexures the hangers may be constructed to press at the ilexures themselves if desired. As shown, one hanger means is shown operating between two adjacent ilexures. If desired, however, one may be used for each ilexure or for any combination of flexures. It is preferred, however, that at least one hanger be provided for not more than three flexures.

Wherev secondary seals are used these seals may be attached to the top marginal area of the sealing ring. They may be held on the sealing ring itself, or may be held by upstanding brackets attached to the ring. Joints between individual sections of the sealing ring may be joined in any manner desired. Thus the ends of adjoining sections may be riveted or bolted together; they may be bent and riveted or bolted;

l or may be joined by flexible sealing members.

These guide means may be any type desired.

One form is to provide a vertical bar attached to the inner surface of the shell and to provide a crimped portion in the sealing ring passing around the bar. The combination of crimped portion and bar will prevent any substantial lateral movement of the sealing ring. Such arrangements will not be necessary on tanks of small diameter.

Having described the invention as related to the embondiments shown in the accompanying drawings, it is intended that theinvention be not limited to any of the details of description unless otherwise specified, but rather be construed broadly within its spirit and scope as set out 1n the accompanying claims.

We claim:

1. In a floating roof tank or the like a hanger means to be attached to the floating roof to support a sealing member against the shell of the tank, said hanger means comprising an elongated, substantially horizontal bracket having its ends pivotally attached to the sealing member i'or pivotal movement in a substantially horizontal plane, the intermediate portion oi' the bracket being spaced from the sealing member, a horizontal pipe supporting the sealing member` and having a yoke end with the yoke portion having one leg above and the other leg below said intermediate portion, a threaded bolt loosely held in said yoke and engaging threads in said intermediate portion, a spring held between the upper end of the bolt and the top surface of the upper yoke his.A a secondy pipe mounted on the noating roof with the rst pipe Vextending therethrough, a roller held by the nrst pipe in rolling contact with the inside of the second pipe. laterally projecting shoulders on the end ofthe vilrst pipe opposite the yoke, an annular closure on the corresponding end of the second pipe through which the first pipe extends, an annular collar on the nrst pipe between the annular closure and the :sol

roller and normally within the second pipe, a spring surrounding the rst pipe and held between the annular closure and the annular collar and normally urging the first pipe in the direction of its yoke end, and adjustable mounting means for lmounting the second pipe on the floating roof.

2. In a iioating roof tank having a shoe for slidably contacting the shell of the tank, support means for the shoe comprising an elongated substantially horizontal bracket having its ends pivotally attached to the shoe for pivotal movement in a substantially horizontal plane, the intermediate portion of the bracket being spaced from the shoe, a horizontal pipe having a yoke end with the yoke portion having one leg above and the other leg below said intermediate portion, attaching means for securing said yoke to said intermediate portion for relative vertical adjustment therebetween, a 'second horizontal pipe mounted on the floating roof and having the first pipe telescoped thereinto, and a spring held 1 inside said second pipe and operating against the ilrst pipe for urging the first pipe toward the shell of the tank. I

3. A support means comprising a base, asealing member having an arcuate portion and adapted to contact a surface, an elongated substantially horizontal bracket having its ends piv- .otally attached to the sealing member for pivotal movement in a substantially horizontal plane with the intermediate portion of the bracket forming a chord of said arc, a rst pipe pivotallyl attached to the intermediate portion of the bracket for pivotal movement in a substantially horizontal plane, a second pipe mounted on the base and having the first pipe telescoped thereinto and supporting saidI` first pipe, and means urging the first pipe awayffrom the second pipe in the direction of the sealing member to press the sealing member against the surface in sealing relation.

FRED L. GOLDSBY.

CLIFFORD M. ORR.

REFERENCES CITED The following references are oi record in the ille of this patent:

UNITED STATES PATENTS