US2538067A

US2538067A - Support for seals for floating roof tanks

Info

Publication number: US2538067A
Application number: US637016A
Authority: US
Inventors: Henry O Wilber
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: ES175182A1

Description

Jam.. 16, 1951 H. o. WILBER 2,538,067

SUPPORT FOR A SEAL FOR FLOATING ROOF TANKS Filed Dsc. 22, 1945 2 Sheets-Sheet l lllmm'lalsmww E69 M51 H. o. WILBER 2,538,067

SUPPORT FOR A SEAL FOR FLOATING ROOF' TANKS Filed Dec. 22, 1945 2 sheets-sheet 2 @Mmmm- 4rI5ati-.interi Jan. 16, 1951 UNITED STATES PATENT OFFICE SUPPORT FOR. `SEALS FOR FLOATING ROOF TANKS Illinois Application December 22, 1945, Serial No. 637,016

(Cl. 22o-26) 6 Claims. l

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

Floating roof tanks are generally used for the storage of volatile liquids where the roof floats on top of the liquid. There is ordinarily an annular area between the edge oi the iloating 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 ofi 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 difficult 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 ring 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 eX'ible so as to follow the contour of the shell if the shell should get out of round. rilhe 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 floating roof tank embodying the invention; Fig. 2 is a vertical section taken along line 2-2 of Fig. 1 Fig, 3 is a horizontal section showing one curvature arrangement oi 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 fieXures 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 accompanyng drawings comprises a shell IB and a iloating roof H therein. The space between the edge of the floating roof and the shell of the tank is provided with a sealing means to prevent 2 evaporation and contamination of the stored liquid.

The sealing means shown comprises an annular sealing ring i2 contacting the inner surface of the shell il) and supported by hanger means i3 mounted around the edge of the floating roof il. The annular sealing ring I2 is provided with spaced vertical exures il! extending between top i5 and bottom l d marginal areas. These marginal 'areas are preferably bent back from the vertical and away from the shell in order to permit the sealing ring to pass over raised sections on the inner surface of the shell.

The lfiexures it are formed in the Sealing ring I2, which is preferably made of sheet metal, and they extend away from the body portion of the sealing ring. The lexures have the form of loops formed in the sheet metal with vinner portions I'I adjacent each other in order to allow for expansion and contraction of the sealing ring. The flexures may be generally rounded, as indicated. These fiexures not only permit expansion and contraction of the ring, but also permit the ring to bend easily. @ne method of making the lexures 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 oi the ring and opposite the rst portion. A third cut-out portion 20 is formed extending from the inner end of the iirst portion, and a fourth cutout portion similar to the third is formed adjacent the other edge of the ring. The third and fourth cut-out portions have one edge 2i substantialiy parallel to its edge of the ring, and have another edge 22 of arcuate shape with the are extending away from its edge oi the ring. The fourth cutout portion is formed in the same manner.- The lexure l 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 2li adjacent the first and second cut-out portions are leit free so as to be slidable relative to each other. This method forms a iiexure i4 having top 25 and bottom 25 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 of hanger means desired may be used to Support the new sealing ring. The hanger means shown comprises a T bar 2T extending between adjacent exures it and attached to the sealing ring I2 by means of short brackets 28.

5a The T bar 27 is loosely held by the brackets 28 in order to permit bending of the section 29 of the sealing ring between adjacent ilexures Ill. This loose connection may be provided by slots Si! provided in the brackets 28 and engaging studs 3l in the ends of the T bar.

The horizontal portion 32 of the T bar 2l! extends toward the iioating roof. A substantially horizontal pipe 33 is provided having a yoke end i with one leg of the yoke above and the other leg below the horizontal portion. A threaded bolt 35 is loosely held in the yoke Sil and engages threads in the horizontal portion 32. The belt 35 extends above the yoke 343, and a spring 36 is located between the upper end of 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 iirst pipe extends. The first pipe 33 is provided with a roller held in top and bottom slots 39 in the first pipe S3 and mounted by means of pin lo for roLing contact with the inside surface of the second pipe i'd. On the end of the irst pipe 33, opposite the yoke 35., there is located a cap 4I closing this end of the pipe. On the corresponding end oi' the second pipe 37 there is located an annular cap i2 having a hole i3 therein through which the first pipe 33 extends. The hole t3 is of suoli size that the cap 2l on the end of the iirst pipe will contact the annular cap 32 when the rst pipe has been extended its iull distance toward the shell of the tank. Between the annular cap and the roller 38 there is provided an annular collar lil on the first pipe 33. This collar is of such diameter that it slides freely within the second pipe Between the annular cap 2 and the collar firithere is provided a spring ll normally urging the first pipe 33 toward the shell of the tank.

ln order to support the second pipe 3? and the first pipe 33 there is provided a third pipe llI, attached near the front end of the second pipe 3l and extending downwardly therefrom. This third pipe abuts the edges of a hole Q8 in a horizontal base plate lil. The third pipe it is rotatably held concentric to the hole 48 by providing a smaller concentric pipe i9 extending through the hole i8 with the concentric pipe being attached to the third pipe as by welding 5e. On the bottom of the concentric pipe t9 there are located three lugs 5I in order to hold the assembly in place. Tn assembling the structure the lugs 5I may be inserted through cut-out portions 52 at the edge of the hole 51S. The lugs 5l and cut-out portions 52 are arranged so that they will not coincide when the hanger means is in use.

The base plate is supported on vertical threaded posts e3 mounted on the deck of the noating roof. rThe base plate is held on the post by means of nuts 5e on either side of the base plate so that the position of the plate may be easily regulated.

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 lll to the second pipe S'I. The spring is attached to the base plate by means of a hole 55 at the rear of 'the plate and is attached to the pipe 3l' by means of a downwardly extending eye 5i. Any type sealing means may be provided between the sealing ring I2 and the edge of the floating roof I i. As shown, this sealing means comprises a nexible sealing member 58 made oi fabric impregnated with a flexible impervious material. The sealing member 58 is attached to the sealing ring by means of bolts 59 extending through a washer bar 62 and the sealing ring I2. The roof edge of the sealing member 58 is attached to the roof by means of hooks 6I holding wedges B2 pressing against a circular rod 63 in contact with the rooi` edge of 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 Iii and the sealing ring I2.

The spring 36 around the top end of bolt 35 is provided so that each of the hanger means I3 will carry its proportionate share of the load of the sealing ring. The bolt 35 serves to adjust the position of the T bar 21 with respect to the rlrst pipe 33 and may be used to even up the load on all hangers. The spring i5 around the first pipe 33 serves to hold the sealing ring tightly against the shell lil. The spring e5 between the base plate il and the second pipe Si 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 :i5 also applies a 'orce tending to restore the pipe 3l to a radial position. The spring 55 reduces the bending moment at the base plate 4? and he-ps 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 of opposite sign as the moment when the roof moves down. This is accomplished by providing a spring that wouid resist a load equal to the Weight of the ysealing 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 il 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 il is mounted on the threaded posts 53 so that each plate can be levelled and adjusted vertically. For proper 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 horizontal plane it is necessary that the base plate be kept substantially 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 flexures should have radii of curvature, when unrestrained, differing 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 2li is less than the radius of the shell and the hanger means press against the ends of the portion 2Q. 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 flexures themselves if desired. As shown, one hanger means is shown operating between two adjacent flexures. If desired, however, one

may be used for each flexure or for any combination of lieXures. It is preferred, however, that at least one hanger be provided for not more than three flexures.

When secondary seals are used these seals may be attached to the top marginal area i5 of the sealing ring. They may be held on the sealing ring itself, or may be heid 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: or may be joined by flexible sealing members.

In large-sized tanks it may be desirable to provide guide means so that the sealing ring will travel in a substantially vertical path only. These guide means may be any type desired. One form is to provide a vertical b-ar 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.

The pipes which are used in constructing the hanger means shown may be round, square, rectangular, or have any other cross-sectional shape.

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

I claim:

1. In a iloating roof tank or the like a hanger means to be attached to the floating roof for supporting a sealing member against the shell of the tank, said hanger means comprising a sub stantially horizontal pipe pivotally attached to and supporting the sealing member for pivotal movement in a horizontal plane, a substantially horizontal second pipe with the first pipe extend ing therethrough, a spring pressing against both pipes and urging the rst pipe in the direction of the sealing member, a mounting means support ing the second pipe on the floating roof for rotation in a substantially horizontal plane, and means for limiting the rotation movement of the second pipe.

2. The hanger means of claim 1 wherein the mounting means comprises a downwardly eX- tending third pipe attached to the second pipe, a base plate normally held in substantially horizontal position and rotatably supporting the third pipe, and a plurality of posts supporting the base plate on the floating roof, the effective length of each of said posts being adjustable in order to regulate the position of the base plate relative to the floating roof, and said limiting means comprises a spring attached to the second pipe and to the base plate.

3. In a floating roof tank having a sealing member adapted to slidably contact the sidewalls of the tank, support means for the sealing member comprising a first pipe having one end pivotally connected to the sealing member for pivotal movement in a substantially horizontal plane, a second pipe supported above the roof, and having the iirst pipe telescoped thereinto, for supporting' the rst pipe and a spring urging the rst pipe away from the second pipe and in the direction of the sealing member.

4. In a floating roof tank having a sealing member adapted to slidably contact the sidewalls of the tank, support means for the sealing member comprising a first pipe supporting the sealing member and having one end pivotally connected thereto for pivotal movement in a substantially horizontal plane, a second pipe supported above the roof, and having the rst pipe telescoped thereinto, for supporting the i'lrst pipe and a spring urging the rst pipe away from the second pipe and in the direction of the sealing member.

5. In a floating roof tank having a sealing member adapted to slidably contact the sidewalls of the tank, support means for the sealing meinber comprising a iirst pipe supporting the sealing member and having one end pivotally oonnected thereto for pivotal movement in a substantially horizontal plane, a second pipe mounted on the roof for rotation about a substantially vertical axis, and having the first pipe telescoped thereinto, for supporting the first pipe, and a spring urging the rst pipe away from the second pipe and in the direction of the sealing member.

6. In a iioating roof tank having a sealing member adapted to slidably contact the sidewalls of the tank, support means for the sealing member comprising a first pipe supporting the sealing member and having one end pivotally connected thereto :for pivotal movement in a substantially horizontal plane, a second pipe surrounding said rst pipe, a spring bearing against the pipes and urging the first pipe in the direction of the sealing member, and a third pipe connected. to the second pipe and being rotatably mounted on the roof for rotation about a substantially vertical axis.

HENRY O. WILBER.

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

UNITED STATES PATENTS Number Name Date 1,493,174 Wiggins May 6, 1924 1 673,984 Kuhl June 19, 1928 2,080,568 Hoenighausen May 18, 1937 2,089,645 Dickmann Aug. 10, 1937 2,313,856 Wiggins Mar. 16, 1943 FOREIGN PATENTS Number Country Date 553,807 Germany July 4, 1932 487,774 Great Britain June 24, 1938