US2857072A

US2857072A - Drain arrangement for floating roof

Info

Publication number: US2857072A
Application number: US586050A
Authority: US
Inventors: Robert W Bodley
Original assignee: Graver Tank and Manufacturing Co Inc
Current assignee: Graver Energy Systems Inc
Priority date: 1956-05-21
Filing date: 1956-05-21
Publication date: 1958-10-21
Anticipated expiration: 1975-10-21

Description

Oct. 21; 1958 v R. w. BODLEY 2,857,072 I DRAIN ARRANGEMENT FOR FLOATING ROOF.

Filed May 21. 1956 3 Sheets-sheaf l i r J 32// C3 rfiio 38 1 INVENTOR.

Oct. 21, 1958 R. w. BODLEY 2,857,072

mum QARRANGIEMENT'FOR FLOATING ROOF Filed May 21, 1956 Y s Sheet-Sheet -2 INVENTOR.

United DRAIN ARRANGEMENT FOR FLOATING ROOF Application May 21, 1956, Serial No. 586,050

12'Claims. (Cl. 220-26) The invention relates to floating roof tanks and more particularly to a novel and improved drain arrangement therefore.

As is well known in the art, floating roof tanks are usually employed to store volatile liquids, such as petroleum products, where the purpose is to control and minimize product losses due to evaporation. of tank, a circular shell having an open top is provided. To close the top, the roof is arranged to floaton the stored product and consequently rises and'falls in response to a change in the'level of the product within the tank. At the normally high position the floating roof is just below the top edge of the tank. The roof may be additionally provided with depending legs which are secured to the under side of the roof, said legs supporting the roof in spaced relation to' the tank bottom when most or all of the product is drainedfrom the tank. It is obvious therefore, that the position of the roof will vary between the mentioned maximum and minimum positions depending on the level of the product in the tank. Floating roofs are of varying types, but, in the usual instance, are saucered when seen in side elevation, to afford the'neces sary buoyancy. -In some instances pontoons are added to the roof to provide additional buoyant effect. Because of the form of the roof, it will naturally collect rainwater and other foreign matter that falls thereon and it is usual toprovide, at a low point on the roof form, a sump orthe like to which the rain water'will drain due to pitch of the roof. In order to preserve the stability and buoyancy of the roof, the collected rain Water must be drained therefrom and this is usually accomplished by providing a conduit communicating with the sump-and extending downwardly therefrom into the tank, through the product stored therein to some outlet point on the tank shell, whereat the conduit communicates with a nozzle or drain to carry away the water.

The conduit employed may be of several types, one of them being a flexible hose drain. In some instances a plurality of sections of rigid pipes having pivotal connections intermediate the sump and outlet are also em ployed. I

It is thought obvious, that in order to satisfactorily drain water from the roof, a gradient from sump to outlet should be maintained during most positions of the roof in the tank. It has been found that the drain conduit frequentlybecomes fouled in the tank destroying the required gradient or blocking the conduit passageway and thus preventing proper drainage of the water from the roof. Where the conduit is allowed to move freely in the tank, it may, for example, become fouled with the legs on the underside of the roof or, in the case of a flexible conduit become tangled in itself, thus interfering with or prohibiting proper drainage.

In order to prevent any of the above mentioned difficulties the disclosed invention provides an improved arrangement having guide means associated therewith that will control movement of the hose drain or flexible conduit in such a manner that proper drainage is assured.

In this form atent Patented Oct. 21, 1958 It is a specific object of the invention to provide a controlling cable having one end thereof secured to the hose drain intermediate the ends of the latter, and the other end thereof secured to the tank shell and arranged to coact with floating roof whereby movement of the roof will cause the cable and connected drain to move in a predetermined pattern.

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 plan view ofa tank incorporating the invention,

Figure 2 is a side elevational view, partly in section, illustrating the structure of Figure 1,

Figure 3 is an-enlarged, fragmentary sectional view showing the connection of the cable to the tank shell,

Figure 3A is a sectional View taken along line 3A3A of Figure 3,

Figure 4 is a side elevational view of a modified embodiment of the invention,

tank comprises a shellfwhich is usually cylindrical in form, and a roof 6 positioned therein andslightly smaller in diameter than the shell 4, whereby the roof may move vertically in the tank in response to the change in product level. Around the periphery of the roof a conventional seal mechanism (not shown) may be employed, as is familiar to those skilled in the art. The tank-additionally may be provided with a wind girder 8 arranged to encircle the outer shell adjacent the top thereof to-provide the proper tank rigidity or resistance to damage due to wind impinging on the shell surface. 7

Directing attention to Figure 2, it will be seen that the roof is shown in low position whereat a plurality of legs 10, secured to the under side of roof, abut the'tank bottom and locate the roof in spaced relation thereto. The roof is shown in phantom at 6a in-the high position whereat it is immediately adjacent the top edge of the tank shell 4. As earlier noted, the roof 6 is'provided with a centrally located sump 12, said roof beingpitched toward thesurnp from all directions, whereby collected water on the roof will drain toward the sump. A hose or conduit 14 is connected to and communicates at one end 16 to the sump 12. The other end of the hose 14 is connected to and communicates with a nozzle 18 in the tank shell 4, preferably adjacent the bottom thereof. 7

Considering Figures 2 and 3, it will be seen that the design provides a bracket 20 secured to the tank shell 4 proferably at the top edge thereof. The bracket20 has an arm 22 which extends inwardly of "the tank shell to overlie a portion of the roof. At the inner end of the arm a cable connection 24-, such as an eye bolt and nut ately below the aperture 28 a cable guide 32 is secured,

to the under side of the roof. In the preferred embodiment the guide comprises a cylindrical element 36 having enlargedfl-anges, 38, 38 on opposite sides thereof.

The cable 26 engages the guide 32 and extends inward- I 1y of the tank to connect) to the hose 14, as at 40, at a point intermediate the ends-of the hose. A weight 42 is Figure 5 is a plan view of the structure shown in Fig-.

:7 3 secured to the cable 26 at a point in spaced relation to the connection 40, said weight keeping the desired tension in the cable 26 during the action hereinafter described, and also assuring that the cable will movein a generally constant vertical path. I

Considering the operation of the disclosed invention the roof will be considered in the high position shown at 6a in Figure 2. In this position thecable 26 and the weight 42 are in elevated position in the tank, and the hose 14 extends downwardly between the sump 12 and the outlet 18. As the roof descends in response to product evacuation, the cable 26 in engagement with the guide 32 pulls the hose 26 toward the shell of the tank. At its low position the hose 14 has the upper and lower portions thereof bent in acute angle relationship to each other, as seen in Figures 1 and 2. It will also be noted that the action of the hose 26 is controlled at all positions of the floating roof in the tank thereby precluding any possibility that the hose will entangle in itself or in the supporting legs 10 during roof action, thereby preventing proper drainage. It will be particularly understood that the connection 40 between the cable and the hose may be a conventional collar connection (not shown) which will prevent any sharp restrictive bend in the hose at this point.

Figures 4 and 5 show a slight modified embodiment of the invention adapted to a high tank having a relatively small diameter. In this embodiment structure identical with that heretofore described is indicated with identical numerals. In general, the increased height of the tank and the consequent necessity of having a relatively longer hose drain requires that the arrangement employ a plurality of guide cables which, in low position of the roof, form the cable into an S-shape or multiple angular shape similar to the preceding embodiment. A plurality of cables 62 are here provided, each having a connection to the hose 60 at spaced points thereon. The upper ends of the cable 62 are secured to the top of the tank shell in a manner similar with the cable 26 of the preceding em- 'bodiment and at spaced

points

64, 64 on said tank shell. As the roof descends in the tank 4, the cables 62 operatively engage the roof as illustrated in Figure 3. The movement of the roof urges the hose 60 into a predetermined folded relationship as shown due to the connection between the cables 62 and the'hose 60. It will be noted that the hose forms a generally S-shaped fold when the roof is in the low position and as seen in both the side elevational view of Figure 4 and the plan view of Figure 5.

Considering the embodiment of Figures 6 and 7, it will be noted that the structural features which are physically similar and identical in function with the features of the previous embodiments, are again given like numerals. It will be seen that the embodiment here employs a hose drain 14a which may be connected to the central sump 16 and the outlet nozzle 18. A flexible cable 26a connects at 40a with an intermediate portion of the hose 14a, said cable extending upwardly through an aperture 28 in the roof Whereat it operatively associates with a pair of pulleys 22a mounted on the tank shell bracket 20a. A weight 42a is connected to the outer extremity of the cable 26a and is free to move vertically a determined distance in response to the action of the cable as hereinafter described. In this embodiment, as the roof 6 descends from its maximum upper position, the cable 26a again urges the hose drain 14a to follow a predetermined pattern of movement. During the initial lowering movement of the roof, the weight 42a occupies its lower position, shown in phantom at the left hand portion of Figure 6. However, as the roof continues to descend and reach a predetermined point, the cable 26a has acted to pull the hose drain 14a to a determined angled condition. At this point the cable 26a is comparatively taut, and continued lowering movement of the roof cannot be accommodated by horizontal movement of the hose drain 14a. Therefore continued lowering movement of the roof may be accommodated by the elfective extension of the length of the cable 26a by virtue of the upward movement of the weight 4211 to its upper position, as shown in solid lines at the left hand side of Figure 6, which illustrates the position of same when the roof has reached its maximum descended condition. In effect, there will be no movement of the weight during initial lowering of the roof,

but the weight will move and accommodate an operative lengthening of the cable 26 during the final stages of the lowering of the root. In this embodiment, the location of the weight at the end of the cable 26a, positively prevents the hose 14a, or any portion thereof from being dragged over the bottom of the tank during controlled movement thereof. Again, movement of the hose 14a is controlled to prevent fouling or other difficulties that may interfere with proper drainage.

Thus it will be seen that the invention provides a novel drain arrangement which remedies the difliculty heretofore found and simply and easily assures a positive trouble free operation required in structures of this nature.

It will be understood that the above is by way of illustration and not limitation and that the invention may be subject to various modifications without departing from the spirit thereof or the scope of the appended claims.

I claim:

1. In a drain arrangement, the combination of an open top tank shell and a roof arranged to float on product therein, a hose connected at one end to a sump on the roof and at the other end to a drain means externally of the tank, guide means being fixedly connected to the hose at a point intermediate the hose ends, said guide means having a direct operative connection to the tank shell, and other means operatively interconnecting the floating roof and the guide means whereby upon downward movement of the roof the guide means exert a generally lateral force on the hose to move same ina predetermined manner in the tank.

2. A drain arrangement according to claim 1, wherein said hose is flexible and the guide means comprises a cable having one end fixedly connected to the hose and another end connected to the tank shell, said cable operatively engaging the roof during movement of the latter.

3. A drain arrangement for a floating roof tank according to claim 2, and including a weight connected to the cable.

4. A drain arrangement according to claim 2, wherein said cable operatively engages the roof in an area immediately adjacent the periphery thereof.

5. In combination, a tank, a floating roof in the tank,

a sump centrally located on the roof to collect foreign p the tank shell below the roof, said hose drain being flexible throughout substantially its entire length, an aperture in the roof immediately adjacent the edge thereof, a flexible cable having one end in operative connection with the tank and extending downwardly through the aperture, said cable being directed inwardly below the roof to a point where its other end is connected to the drain intermediate the ends thereof, a pulley-like element on the roof and below the aperture and engaging the cable, whereby upon downward movement of the roof, said pulley-like element operatively engages the cable to exert a lateral movable force on the latter whereby the hose drain is moved in a determined generally horizontal pattern in the tank.

6. In combination, a tank, a floating roof in the tank, a sump on the roof to collect foreign matter deposited on the roof, a flexible hose drain communicating with sump and extending downwardly into the tank, said drain communicating with an outlet in the tank shell below the roof, at least one bracket mounted on the tank adjacent the upper edge thereof and above the roof, at least one tal direction and in a determined pattern in the tank.

7. The combination of claim 6, and including weight means associated with the member.

8. A drain arrangement according to claim 7, wherein said operative connection between the guide member and bracket is a direct fixed connection.

9. In a drain arrangement for a tank having a floating roof, a sump in the roof, a flexible hose drain communicating with the sump and extending downwardly through the tank to an outlet, a plurality of guide cables having certain ends connected to the tank adjacent the upper edge thereof, said cables extending downwardly into the tank and having their other ends connected to the drain at spaced points thereon, said cables operatively engaging the roof whereby downward movement of the latter urges the drain into a predetermined S-shaped pattern.

10. In a drain arrangement, the combination of an open top tank shell and a floating roof arranged to be supported on product therein, a hose connected at one 6 end to a central sump on the roof and at the other end to drain means externally of the tank, guide means comprising a generally flexible cable having one end thereof fixedly connected to the hose intermediate the ends of the latter, the other end of said cable being operatively and movably connected to the tank shell, and movable weight means operatively associated with the second mentioned end of the cable, said cable operatively engaging and coacting with the roof adjacent the periphery of the latter and during vertical movement thereof so that the cable exerts a generally lateral force on the hose urging the latter to move in a determined generally horizontal pattern in the tank.

11. A drain arrangement according to claim 10, wherein said operative connection between the tank shell and the cable comprises pulley means on the shell operatively engaging the cable. p

12. A drain arrangement according to claim 11, wherein said weight means is operative to move only during certain portions of the movement of the roof.

References Cited in the file of this patent UNITED STATES PATENTS