US3343708A - Floatable seal for pillar supported tanks - Google Patents

Description

Sept. 26, 1967 M. F. HAAS 3,343,708

FLOATABLE SEAL FOR PILLAR SUPPORTED TANKS Filed May 22, 1961 5 sheets-sheet 1 AUM/m.

Sept. 26, 1967 M. F. HAAs 3,343,708`

FLOATABLE SEAL FOR PILLAR SUPPORTED TANKS Filed May 22, 1961 5 sneets-sneet 2f MMM Sept. 26, 1967 M. F. HAAs FLOATABLE SEAL FOR PILLAR SUPPORTED TANKS Filed May 22, 1961 :s sheets-sheet s INVENToR. 1l/FORD f.' HAAS BY /W (www United States Patent O 3,343,708 FLOATABLE SEAL FOR PILLAR SUPPORTED TANKS Milford F. Haas, Brooklyn, N.Y., assignor to Mayflower Vapor Seal Corporation, Little Ferry, NJ., a corporation of New `llersey Filed May 22, 1961, Ser. No. 123,332 8 Claims. (Cl. 220-26) The present invention relates to an inflatable, mobile, iloatable seal for use in pillar supported tanks and particularly in tanks used to store volatile and inflammable liquids such as gasoline and the like. Such products, in the presence of air, or when subjected to higher temperatures, are inclined to change from the liquid to the gaseous state resulting in a loss of the product and increasing the possibility of fire or an explosion.

In order to prevent loss from evaporation and to minimize danger, most storage tanks are sealed, are filled from the bottom and are inaccessible except for a manhole in the top. It is therefore difficult to cover the liquid in a partially filled tank and for personnel to install any such sealing device from within the tank under such circumstances. This problem is all the more aggravated when there is a pillar roof support within the tank and where the cover must fit tightly about the pillar; the pillar and surrounding cover collar not being within reach from the roof manhole position at the edge of the tank roof.

It is therefore the primary object of this invention to provide an inflatable, lloatable seal for tanks with a pillar supported roof where the tank cannot be taken out of service and Where the installati-on must be carried out from outside the tank through the roof manhole.

A serious problem arises in the storage of highly volatile liquids due to the evaporation losses occasioned by surface vaporization especially when aggravated by convection currents set up in the vapor space over the liquid surface under the influence of the suns rays striking against the outside of the tank. Such losses result not only from the breathing losses caused by the expansion and contraction of the vapors above the liquid, but also are caused by fluctuations in the liquid level produced by the introduction and withdrawal of the liquid contents of the tank.

When the tank is not too big and has no supporting pillars, a floatable partition similar to that shown and described in the patent to McClintock et al., No. 2,847,142 issued Aug. l2, 1958 may be used. This partition may not be used however in a tank where the roof is reinforced by pillars or supporting posts.

It is an object of the present invention to provide a floatable inflatable seal which may be inserted into a tank having a supporting pillar without taking the tank out of service or interrupting the normal operation of the tank and without allowing the escape of vapor around the pillar or at any other point.

A further object is to provide a structure which will envelop the post or pillar and seal off the escape of gases around it, this structure being capable of being placed into correct position around the pillar from a roof manhole location remote from the pillar and without taking the tank out of service of interrupting normal tank operation.

A still further object is to provide a structure which will accommodate itself to posts or pillars of different configurations when installed at a roof manhole location remote from the pillar.

A seal of the type shown and described in the patent to McClintock et al., No. 2,847,142 will ship aboard large quantities of liquid when inserted into a tank service,

especially when inexperienced personnel attempt to inice stall this seal. In this type of seal the liquid tends to collect in one place making a bag-like form or shape in the bottom membrane or diaphragm. Under this condition when the seal is inflated the air ring or torus kinks and folds and therefore will not fully contact the tank walls. This condition is only relieved by pumping out the product from within the boundaries lof the air ring or torus wall.

In tanks with a single pillar roof support centrally located, each half or section of the seal must assume the proper shape even when only partially inflated, as each half must be stift enough to be readily maneuvered from a location rem-ote from the center pillar support into the correct position about the center pillar support; while at the same time not being fully inflated, where the seal is physically too large to move in any direction but up and down and thus could not be manipulated int-o correct position about the pillar support at full operating inflation pressure. When each half or section is in correct position, full operating or working inflation pressure is applied and locks the seal into a vapor tight position about the center pillar support and the tank walls. Once full inflation pressure is applied the 'diameter of the seal would be larger than the inside diameter of the tank if not confined by the tank walls, thus all but an up and down movement of the seal is prevented, and rotational or transverse location movements are prohibited.

As will be clear from the foregoing a seal with a bottom membrane or diaphragm where liquid will collect and distort the seal shape, will not allow the halves or sections of the seal to be maneuvered into correct position from a remotely located roof manhole position.

For this reason I provide seals for use in pillar support-ed tanks with a self draining or emptying membrane or diaphragm. This membrane or diaphragm is suspended above the liquid level of the tank and is equipped with special buoyant type check valves and drain tubes which will allow any liquid present on the membrane or diaphragm to drain oil through the check valves and drain tubes and will prevent the escape of product vapor during the normal operation of the seal and the flooding of the seal membrane or diaphragm during the installation of the seal. Therefore when each half or section is only partiallyV inflated during installation any liquid present on the seal will drain off, the seal will take the proper shape, allowing the halves or sections to be positioned into the correct position about the pillar support ready to be locked in place by the final working pressure inflation.

Therefore a primary object of this invention for use in pillar supported tanks is to provide a self draining or emptying type of membrane or diaphragm suspended above the tank liquid, equipped with buoyant type check valves and drain tubes, to drain oil any liquid on the seal and thus make possible the manipulation of the seal halves or sections into correct position about the pillar roof support; this being accomplished from a roof manhole position remote from the said pillar roof support.

The invention and its objects may be more fully understood from the following description when it is read in conjunction withthe accompanying drawings, in which:

FIG. 1 is a top plan view partly in section, showing the invention in a tank.

FIG. 2 is a side elevation also partly in section.

FIG. 3 is an enlarged sectional view of the side seal. FIG. 4 is a detailed view showing a center seal around a pillar.

FIG. 5 is a sectional view taken on the line 5-5 of FIG. 4.

FIG. 5A is an enlarged sectional view taken on the line SA-SA of FIG. 4.

FIG. 6 is an enlarged sectional view showing the seal around a post.

FIG. 7 is a cross-sectional view of the buoyant check valve in one position during installation showing how the buoyant check valve raises the membrane above the level of the liquid.

FIG. 8 is a view similar to FIG. 7 showing the action of the valve after installation and the self draining of the membrane of any liquid above the membrane.

FIG. 9 is a similar view showing the membrane and valve in operating position after installation has been completed and all liquid drained from the top of the membrane.

PIG. 10 is a top plan view of the valve float.

Referring more particularly to the drawings, the tank 10 is of a more or less conventional type having side walls 11 and a roof 12 with a manhole 13 and a cover therefor 14, The roof is supported by the walls 11 and a central post or pillar 1S.

Floating on the liquid at level 16 is the multiple sealing unit consisting of the sections 17 and 18 each of which is provided with a special buoyant type of check valve and drain 19. It will be understood that the sealing unit rides up and down within the tank as the supply of liquid in the tank rises or falls.

Each of the sealing units 17 and 18 consists of a body portion made of a material which is not affected by gasoline or petroleum such as an impregnated plastic. It is generally semi-annular in shape and is supplied with a semi-annular inflatable pontoon 20 having a deformable tubular auxiliary member 32 which engages the inner wall of the tank and the abutting diameters of sections 17 and 18 to prevent the passage of vapors. It may also be provided with a flexible vertical sealing bulk-head or skirt 33 to seal olf the vapors within the boundaries of the semi-annular inflatable pontoon 20, as in some cases the pontoon does not `fully contact the liquid surface throughout its entire periphery, due to uneven stresses in the pontoon casing or seal membrane or when following the liquid level in withdrawal operations a portion of the pontoon may temporarily not be in Contact with the tank liquid.

The sealing units abut each other to complete the seal, generally in a more or less straight line across the center of the tank and the abutting surfaces are provided with engaging or junction pontoons 34 and 24 and deformable tubular auxiliary members 32.

Both of the pontoons are provided with expandable means to accommodate the post or pillar 15. Where there is more than one post or pillar, there will be as many such structures as there are posts or pillars to accommodate.

A preferred form of such structure is shown in detail in FIG. 6 although the structure may be varied to t the need.

The structure shown in the drawings is designed to accommodate posts or pillars of different shape whether round, I beam or H beam in shape.

As shown in FIG. 6 and elsewhere, I provide a pair of depending members 25 attached to the deformable tubular auxiliary members 32 and to the rigid walls of the cavity or recess 28, these depending members extending below the tank liquid level as shown in FIG. A. The recess 28 and the depending members 25 surround three sides of the post 15. The recess 28 is provided with a flexible seal 26 which may include a plurality of flexible and resilient flaps 27 adapted to conform themselves to the contours of the post or pillar 15.

In practice these may be covered with a ilexible sheet 27' to prevent any seepage of vapors.

The members 25 as well as the deformable tubular auxiliary members 32 are abutted by the edge of the cooperating section to form a complete sealing unit.

In order to urge the abutting edges of the deformable tubular members 32 and 25 into close sealing contact, I provide an air spring 36 extending from the center of the pontoons 24 and 34 to the semi-annular pontoons 20.

The air spring 30 is independently inflated by means of a valve 31 and is tubular in cross section.

Air pressure of sucient strength may be introduced to insure sealing contact not only between the sealing units 17 and 18 but also between the units and the side walls of the tank.

This pressure is controlled so that while it maintains sealing, it will still allow the unit to move up and down with the level of the material in the tank.

As has been previously pointed out, the seal is subjected to flooding during installation in a tank in service and accumulation of condensation and accidental product discharge upon it during its service life.

In or-der to circumvent the above conditions, I provide a self-draining or emptying type membrane suspended above the tank liquid, this membrane being provided with a plurality of a special buoyant type of drain and check valve which will prevent flooding by the buoyant action of the valve itself, which lloats the drain ports above the tank liquid in addition to the valve iioat closing off these ports and thus a double positive, check function is performed. In addition the valve acts as a drain throughout the service life of the seal allowing the condensation of product accumulation to drain off and acts as a check valve to prevent vapors beneath the seal membrane from escaping through the drain ports.

A preferred form of the buoyant drain and check valve together with the self-draining membrane or diaphragm is shown in FIGS. 7, 8, 9 and l0.

The buoyant drain and check valve 21 is provided, one or more, as necessary for each section. It consists of a chamber 35 having a flexible drain 22 extending below the level of the liquid so that no vapors can escape regardless of the position of the oat 23. The float Z3 is smaller in diameter than the chamber 35 in order to allow liquid to drain around the periphery of the iloat. When liquid enters into the chamber 35, from backiiow through the flexible drain 22, the float rises, presses against the membrane drain ports, closing them to liquid flow and at the same time raises these drain ports (as shown in FIG. 7) above the liquid level; providing a positive action or check against back flow of any liquid onto the membrane or diaphragm.

When the liquid enters the chamber 35, through the membrane drain ports, the float raises off the bottom chamber drain port, allowing the liquid in the chamber to drain through the port and liexible drain 22. The valve is designed so that the rate of liquid flow through the membrane drain ports is less than through the bottom chamber port, therefore preventing the float from raising against the membrane ports and thus intermittingly interrupting liquid flow. (see FIG. 8).

When all liquid has drained from the membrane or diaphragm, the oat then drops to cover the chamber botton port, thus sealing all vapors within the flexible drain 22 and preventing vapors below the membrane or diaphragm from escaping through the drain and check valve.

I claim:

1. A collapsible oating seal assembly for positioning within an enclosed tank having one or more supporting pillars for the roof section of the tank, the assembly being constructed for disposition upon the surface of readily vaporizable liquid within the tank, the assembly comprising a plurality of separate units, each unit being capable of separate handling and having an effective area of less than the total area of the liquid surface, all of the units, when positioned on the liquid surface, floating thereon and tting together to cover substantially the entire liquid surface, each unit having edge portions to fit to the tank walls and edge portions to conform to adjacent edge portions of other of the units, certain of said edge portions being shaped to conform to the transverse cross-section of a supporting pillar, each separate unit having inflatable pontoon elements extending about the edge portions at the periphery of that separate unit, means for forcing pontoon elements of the units, when all of the units are positioned in the tank, into engagement with each other to cooperate to form a substantially continuous peripheral pontoon member conforming to the contouring of the tank walls and other immediately adjacent pontoon elements of other of the units, and edge portions at a supporting pillar engaging thereagainst, deformable cushioning members carried by the pontoon elements for direct engagement with the tank walls, and with each other at other of the edge portions of the units, and a substantially imperforate body portion for each unit extending between the pontoon elements of that unit, and all cooperating to seal against the passage of vapor from the liquid past the assembly.

2. A collapsible floating seal assembly for positioning within an enclosed tank having one or more supporting pillars for the roof section of the tank, the assembly being constructed for disposition upon the surface of readily vaporizable liquid within the tank, the assembly comp-rising a plurality of separate units, each unit being capable of separate handling and having an effective area of less than the total area of the liquid surface, all of the units, when positioned on the liquid surface, floating thereon and fitting together to cover substantially the entire liquid surface, each unit having edge portions to fit to the tank walls and edge portions to conform to adjacent edge portions of other of the units, certain of said edge portions being shaped to conform to the transverse cross-section of a supporting pillar, each separate unit having inflatable pontoon elements extending about the edge portions at the periphery of that separate unit, means for forcing pontoon elements of the units, when all of the units are positioned in the tank, into engagement with each other to cooperate to form a substantially continuous peripheral pontoon member conforming to the contouring of the tank walls and other immediately adjacent pontoon elements of other of the units, and edge portions at a supporting pillar engaging thereagainest, hollow deformable cushoning members carried by the pontoon elements for direct engagement with the tan-k walls, and with each other at other of the edge portions of the units, and a substantially imperforate body portion for each unit extending between the pontoon elements of that unit, and all cooperating to seal against the pillar to prevent passage of vapor from the liquid past the assembly.

3. A collapsible floating seal assembly for positioning within an enclosed tank, the assembly being constructed for disposition upon the surface of readily vaporizable liquid within the tank, the assembly comprising a unit including a substantially imperforate body portion, and a peripheral pontoon forming means for floating the assembly on the liquid surface to cover substantially the entire liquid surface, pontoon elements of the unit providing means to engage the tank walls for sealing off against movement lof vapor from the liquid past the assembly, and an inflatable member extending substantially from edge to edge of the unit, said member, on being inflated, providing means to move the peripheral pontoon into engagement with the tank walls.

4. A collapsible floating seal assembly for positioning within an enclosed tank, the assembly being constructed for disposition upon the surface of readily vaporizable liquid within the tank, the assembly comprising a unit including a substantially imperforate body portion, and a peripheral inflatable pontoon forming means for floating the assembly on the liquid surface to cover substantially the entire liquid surface, pontoon elements of the unit providing means to engage the tank walls for sealing off against movement of vapor from the liquid past the assembly, and a member extending substantially from edge to edge of the unit and being inflatable independently of the pontoon, said member, on being inflated, providing means to move the peripheral pontoon into engagement with the tank walls.

5. A collapsible floating assembly for positioning within an enclosed tank having one or more supporting pillars for the r-oof section of the tank, the assembly 4being constructed for disposition upon the surface of readily vaporizable liquid within the tank, the assembly comprising a plurality o-f separate units, each unit being capable o-f separate handling and having an effective area of less than the total area of the liquid surface, all of the units, when positioned on the liquid surface, floating thereon and fitting together to cover substantially the entire liquid surface, each unit having edge portions to fit to the tank walls and edge portions to conform to adjacent edge portions of other of the units, certain of said edge portions being shaped to conform to the transverse cross-section of a supporting pillar, each separate unit comprising a substantially imperforate body portion, and an inflatable p-ontoon element extending about the edge portions at the periphery of that separate unit, means for forcing pontoon elements of the units, when all of the units are positioned in the tank, cooperating to form a substantially continuous pontoon member conforming to the contouring of the tank walls and other pontoon elements engaging immediately adjacent pontoon elements of other of the units, and edge portions at a supporting pillar engaging thereagainst, and an inflatable member extending substantially from edge to edge of the unit, said member, on being inflated, providing means to move the pontoon member into engagement with the tank walls, and with other pontoon elements at other edge portions, and all cooperating to seal against the passage of vapor from the liquid past the assembly.

6. A collapsible floating seal assembly for positioning within an enclosed tank having one or more supporting pillars for the roof section of the tank, the assembly being constructed for disposition upon the surface of readily vaporizable liquid Within the tank, the assembly comprising a plurality of separate units, each unit being capable of separate handling and having an effective area of less than the total area of the liquid surface, all of the units, when positioned on the liquid surface, floating thereon and fitting together to cover substantially the entire liquid surface, each unit having edge portions to fit to the tank walls, and edge portions to conform to adjacent edge portions of other of the units, each separate unit comprising a substantially imperforate body portion, and an in latable pontoon element extending about the edge portions at the periphery of that separate unit, means for forcing pontoon elements of the units, when all of the units are positioned in the tank, into engagement with each other to cooperate to form a substantially continuous peripheral pontoon member conforming to the contouring of the tank walls and other immediately adjacent pontoon elements of other of the units, and an inflatable member extending substantially from edge to edge of the unit, said member, on being inflated, providing means to move the pontoon member into engagement with the tank walls and other pontoon elements at other edge portions, and all cooperating to prevent movement of vapor from the liquid past the assembly.

7. A collapsible floating seal assembly for positioning within an enclosed tank having one or more supporting pillars for the roof section of the tank, the assembly being constructed for disposition upon the surface of readily vaporizable liquid within the tank, the assembly comprising a plurality of separate units, each unit being capable of separate handling and having an effective area of less than the total area of the liquid surface, all of the units, when positioned on the liquid surface, floating thereon and fitting together to cover substantially the entire liquid surface, each unit having edge portions to fit to the tank Walls and edge portions to conform to adjacent edge portions of other of the units, certain of said edge portions being shaped and having depending sections t-o engage against and conform to the transverse cross-section of a supporting pillar, each separate unit comprising a substantially imperforate body portion, and in inflatable pontoon element extending about the edge portions at the periphery of that separate unit, means for forcing pontoon elements of the units, when all of the units are positioned in the tank, into engagement with each other to cooperate to form a substantially continuous peripheral pontoon member conforming to the contouring of the tank Walls and 4other immediately adjacent pontoon elements of other of the units, and edge portions at a supporting pillar engaging thereagainst, deformable cushioning members carried by the pontoon elements for direct engagement with the tank Walls, and with each other at other edge portions of other of the units, and an inatable member extending substantially from edge to edge of the unit, said member, on being inflated, providing means to move the pontoon member into engagement with the tank walls and other pontoon elements at other edge portions into engagement With each other, and all cooperating to seal against the passage of vapor from the liquid past the assembly.

8. A collapsible floating seal assembly for positioning within an enclosed tank having one or more supporting pillars for the roof section of the tank, the assembly being constructed for disposition upon the surface of readily vaporazible liquid within the tank, the assembly comprising a plurality of sepa-rate units each capable of separate handling, all of the units, when positioned on the liquid surface, floating thereon and tting together to cover substantially the entire liquid surface, each unit comprising a substantially imperforate body portion having edge portions to fit to the tank Walls and edge portions to conform to and fit against edge portions of other of the assembled units, certain of said edge portions being contoured to conform to the transverse cross-section of a supporting pillar, each separate unit having inflatable pontoon elements extending about the edge portions at the periphery of that unit, the pontoon elements carrying separate deformable elements cooperating to engage the tank Walls and immediately adjacent pontoon elements of other of the units and against the pillars to prevent passage of vapor, those pontoon elements providing for engagement with the tank Walls having a skirt depending therefrom to a level below the top surface of liquid in the tank, each body portion carrying a valve having buoyant means for permitting liquid to drain from the top surface of the body portion to the liquid in the tank, and to prevent liquid or liquid vapor from passing from the tank to the top surface of the body portion, and drainage means depending from the valve a distance to a point just below the surface of the liquid in the tank, the valve and the drainage means being sealed against passage of liquid vapor therethrough from above the liquid in the tank.

References Cited UNITED STATES PATENTS 1,611,440 12/ 1926 Haupt 220-26 1,674,038 1/1928 Glass 220-26 2,070,828 2/1937 Ellis et al. 220-26 2,307,508 1/ 1943 Jayne 2204-26 2,281,748 5/1942 Carney 220-26 2,560,586 7/ 1951 Michaels 220-26 2,847,142 8/1958 McClintock et al. 220-26 2,867,346 1/1959 Champagnat 220-26 2,919,047 12/ 1959 Fino 220-26 2,986,302 5/1961 Paulet 220-26 FOREIGN PATENTS 534,204 10/ 1955 Italy.

THERON E. CONDON, Primary Examiner.

EARL I, DRUMMOND, Examiner.

R. A. JENSEN, R. H. SCHWARTZ, Assistant Examiners.

Claims (1)

1. A COLLAPSIBLE FLOATING SEAL ASSEMBLY FOR POSITIONING WITHIN AN ENCLOSED TANK HAVING ONE OR MORE SUPPORTING PILLARS FOR THE ROOF SECTION OF THE TANK, THE ASSEMBLY BEING CONSTRUCTED FOR DISPOSITION UPON THE SURFACE OF READILY VAPORIZABLE LIQUID WITHIN THE TANK, THE ASSEMBLY COMPRISING A PLURALITY OF SEPARATE UNITS, EACH UNIT BEING CAPABLE OF SEPARATE HANDLING AND HAVING AN EFFECTIVE AREA OF LESS THAN THE TOTAL AREAS OF THE LIQUID SURFACE, ALL OF THE UNITS, WHEN POSITIONED ON THE LIQUID SURFACE, FLOATING THEREON AND FITTING TOGETHER TO COVER SUBSTANTIALLY THE ENTIRE LIQUID SURFACE, EACH UNIT HAVING EDGE PORTIONS TO FIT TO THE TANK WALLS AND EDGE PORTIONS TO CONFORM TO ADJACENT EDGE PORTIONS OF OTHER OF THE UNITS, CERTAIN OF SAID EDGE PORTIONS BEING SHAPED TO CONFORM TO THE TRANSVERSE CROSS-SECTION OF A SUPPORTING PILLAR, EACH SEPARATE UNJIT HAVING INFLATABLE PONTOON ELEMENTS EXTENDING ABOUT THE EDGE PORTIONS AT THE PERIPHERY OF THAT SEPARATE UNIT, WHEN ALL OF THE UNITS ARE PONTOON ELEMENTS OF THE UNITS, WHEN ALL OF THE UNITS ARE POSITIONED IN THE TANK, INTO ENGAGEMENT WITH EACH OTHER TO COOPERATE TO FORM A SUBSTANTIALLY CONTINUOUS PERIPHERAL PONTOON MEMBER CONFORMING TO THE CONTOURING OF THE TANK WALLS AND OTHER IMMEDIATELY ADJACENT PONTOON ELEMENTS OF OTHER OF THE UNITS, AND EDGE PORTIONS AT A SUPPORTING PILLAR ENGAGING THEREAGAINST, DEFORMABLE CUSHIONING MEMBERS CARRIED BY THE PONTOON ELEMENTS FOR DIRECT ENGAGEMENT WITH THE TANK WALLS, AND WITH EACH OTHER AT OTHER OF THE EDGE PORTIONS OF THE UNITS, AND A SUBSTANTIALLY IMPERFORATE BODY PORTION FOR EACH INIT EXTENDING BETWEEN THE PONTOON ELEMENTS OF THAT UNIT, AND ALL COOPERATING TO SEAL AGAINST THE PASSAGE OF VAPOR FROM THE LIQUID PAST THE ASSEMBLY.

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