AU647748B2 - Storage tank having improved empty strength - Google Patents

Description

ii 2 i* x- s u i 41 1 COMMO NWEALTH OF AUSTRALIA PATENTS ACT 1952 COMPLETE SPECIFICATION (Original) FOR OFFICE USE Class Int. Class Application Number: Lodged: Complete Specification Lodged: Accepted: Published: Priority: Related Art: I I: I II Ir I

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Name of Applicant: Address of Applicant: Actual Inventor(s): Creeks Metal Industries Pty Ltd 491 Mountain Highway Baywater, Victoria, 3153 John Patrick Wynne Graeme John Hone Peter John Damen Address for Service: DAVIES COLLISON, Patent Attorneys, 1 Little Collins Street, Melbourne, 3000.

Ct Complete Specification for the invention entitled: Storage Tank Having Improved Empty Strength The following statement is a full description of this invention, including the best method of performing it known to us: -1- -2- "STORAGE TANK HAVING IMPROVED EMPTY STRENGTH" Field of the Invention This invention relates to storage tanks and has particular application to storage tanks which may be readily dismantled and relocated.

Background Art Australian Standard Patent 579858 and Petty Patent 562353, now assigned to the present applicant, disclosed a form of storage tank which may be readily dismantled and relocated. The tank is formed from a plurality of panels which are curved and overlapped at their longer edges to form a continuous tank wall.

The panels have spaced vertical ribs for enhanced strength and the structure is secured together by multiple metal straps which encircle the tank wall through a sequence of loops pressed outwardly from the panels between adjacent slots. The ends of the straps are overlapped and fastened together.

Encircling tensioned wires rather than straps are proposed for securing silo constructions in British Patent 541280 and French Patent Publication 2426391, 20 and for a manure tank of concrete slabs in U.S. Patent 4207716. US patent 2378128 discloses the use of encircling tie rods supported by saddles on upright channel posts which separate and receive the successive tank panels.

The dismantable tank construction proposed in the Australian patents has provided a useful method for large scale temporary storage in remoter rural areas.

j 25 However, it has been found to suffer from a significant disadvantage in that the 4 tank has inadequate empty strength. By this is meant that the tank is susceptible to wind blown distortion or displacement when empty or nearly empty, simply because the tank itself is of light weight relative to the surface area it presents to the wind, and its curved wall is only constrained against distortion from circular or elliptical by the contents of the tank.

The inadequate empty strength of the dismantable tank also restricts the conditions under which the tank may be erected. It cannot practicably be erected i -3if the wind prevailing on the day is any more than a light breeze.

One prior approach to this problem has been to provide heavy duty curved steel angle sections on top of the tank walls and to interconnect these sections across the top of the tank. This approach has improved the empty stability of the tanks but its practice contradicts an important advantage of the dismantable tank system disclosed in the Australian Patents, i.e. the ability to transport all of the components of the tank in a relatively thin pallet package which can be handled by one or two people.

It is thus an objective of the invention to at least in part alleviate the problem of the inadequate empty strength of the dismantable tanks of the prior art. This objective is met, in essence, in a manner which is unexpectedly effective, the provision of a dismantable external frame for the tank which is designed to complement the easily transported nature of the tank.

It is of course known to provide frames to support tanks or like enclosures but these frames are typically an inherent part of the primary supporting structure. Examples include the use of spaced upright steel channel posts to separate and receive successive concrete slabs. The aforementioned US patent 2378128 discloses a similar arrangement, and in that case the channel posts are interconnected by encircling tie rods. In the steel tank structure of British patent 1103455, upright steel ribs, interconnected by encircling tendons, are fastened to the outer wall of the tank by welding, riveting or bolting.

Australian patent 534334 describes a frame of tubular uprights and horizontal curved tubular members as the sole support for a flexible fabric i ,c container which is effectively suspended within the frame from its upper rim.

dl* 25 In contrast to these structures, the present invention proposes the supplementary support of a dismantable tank structure which is itself normally self-supporting when full or partially full, by means of a distinct frame which is also dismantable.

Summary of the Invention The invention accordingly provides, a dismantable storage tank assembly -4which includes a dismantable tank with a wall defined by a plurality of panel members. A plurality of elongate uprights is arranged at spaced intervals about the tank wall, and a plurality of curved rail members interconnect and are detachably secured to each adjacent pair of these uprights. The rail members thereby collectively encircle the tank wall. Means is provided to detachably couple at least some of the uprights and/or the rail members to the tank at spaced locations about the tank. The tank assembly may thereby be dismantled by detaching the coupling means and separating the uprights, rail members and panel members.

The invention also affords a kit for a dismantable storage tank assembly, which includes a plurality of panel members erectable to define a wall for a dismantable tank. A plurality of similar substantially straight elongate frame members are adapted to be arranged as uprights at spaced intervals about the tank wall. The kit further includes a plurality of similar rail members, and means to interconnect and detachably secure the rail members to the uprights so that the rail members curve about and collectively encircle the tank wall, there being a plurality of rail members between each adjacent pair of the uprights. Means is provided to detachably couple at least some of the uprights and/or the rail members to the tank at spaced locations about the tank.

20 a reoeainklfe.fgdala comprising: a plurality of elongate uprights arranged at space rvals about a space for a tank, a plurality of curved rail memb terconnecting and detachably secured to each adjacent pair e uprights, which rail members thereby S 25 collectively encircle t ce, and means to detachably couple at least some of the uprigh or the rail members, at spaced locations about the space, to a There may be, for example, six uprights and the number of uprights may be of the order of half the number of tank panel members. The uprights and the rail members are preferably metal tubes, most preferably of steel but they may be of a lightweight material such as aluminium, and the coupling means may comprise a multiplicity of clips attached between an uppermost rail member and the top edge of the tank wall.

Brief Description of ihe Drawings The invention will now be further described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a perspective view of an erected dismantable storage tank assembly in accordance with a preferred embodiment of the invention; Figure 2 is a fragmentary perspective detail showing the manner in which the rail members of the frame are joined to the uprights; Figure 3 is an enlarged fragmentary view depicting the clips by which the tank wall is supported by the upper rails; Figure 4 is a cross-section on the line 4-4 in Figure 3; and Figure 5 is a perspective view of the tank assembly when roofed.

Description of Preferred Embodiment The illustrated assembly includes a dismantable round storage tank supported within a dismantable frame 12. Tank 10 may conveniently be generally of the form described in Australian Patent 579858 and corresponding allowed US patent application 009056, and to that end typically includes an array of vertically L ribbed galvanised steel panels 14 overlapped at their longer edges and retained as an assembled wall 15 for the tank by a multiplicity, typically six, of metal straps 16 which encircle wall 15. Straps 16 are overlapped end to end and are supported S 25 in multiple loops 18 pressed outwardly from and integral with the panels between adjacent vertical slots 19 (best seen in Figure The straps 16 are typically fastened to the wall panels 14 at regular intervals, e.g. by bolts 16a, and are closer together towards the bottom of the tank than towards to the top. Wires or tendons may be used instead of straps. Panel 14 will usually include integral vertical and/or horizontal ribs for enhanced strength, but these are not shown.

Frame 12 essentially comprises a set of relatively thin steel tubes of common cross-section, including six straight uprights 20 and a pair of rails 22, 23 -6between each upright. Rails 22, 23 are arranged so as to collectively bound the space occupied by tank 10, and to encircle this space in two planes adjacent the top and bottom of the tank. The tubes may be, of outside diameter about mm and inside diameter about 20 mm. Each of the uprights 20 carries a footplate 21 which supports the upright on the ground during construction of the frame and tank. A hole has been punched from the centre of each plate 21 to form a shallow annular lip about the hole. This lip is received in a tight fit withir the respective tube. The footplates 21 may be attached to the tube but are preferably not so attached. The inner half of each footplate lies under the weighted tank liner when the tank is filled or partly filled.

The rails are attached to the uprights in oppositely projecting pairs by means of the simple clamping devices depicted in Figure 2. Two complementary elongate transversely concave plates 23a, 23b are enlarged at their centres to provide a vertical opening 26 for the respective upright and when their cavities 15 are opposed, provide sockets 28 for the rails 22, 23. The two plates are fastened t L together by bolts 29 on either side of the upright and these bolts serve both to clamp the sockets 28 onto the rails 22, 23 and to clamp the plates onto the upright The number and spacing of the uprights may of course vary according to the tank size, but a significant consideration in this respect arises from the transportation of the frame components. A box will normally be provided for the tank components and optimal economy in filling of the box will be provided where the chord length of the curved rails is similar to the length of the uprights.

It is also desirable that the rails not be too long so that the required width of the box to accommodate the curve is not excessive and the box is still of a convenient size, especially in relation to the size of the pallet required for transporting the panels of the tank. Although the rails could be manufactured straight and curved on site, it would generally be preferable for them to be curved in the factory.

The assembled tank is supported from the frame by a series of clips which attach to the upper rails and to the top edge 15a of the tank wall defined by the panels 14. With particular reference to Figures 3 and 4, each clip is essentially a flat strap 32 reinforced by a central outside rib 34 extending -7between an inturned upper lip 36 and a curved part-annular lower seat 38 for the respective rail. The lip is downturned slightly and the dimensions of the clip chosen so that a snap action is required to locate the lip 36 onto the wall edge and sent 38 about the rail, and to subsequently remove the clip when desired.

In practice, the top edge 15a of the wall 15 will be covered by the overhanging upper rim 40 of a tank liner 45 which is retained in place on the wall by a series of U-shaped spring clips 42.

A tank 10 is typically erected at a chosen site by first clearing and levelling the site. The frame 12 is then set up by successively locating the uprights and using the clamping devices 25 to install the rails at the appropriate heights. In ole of the sections between adjacent uprights, one or both rails are initially omitted to facilitate access to the space within the frame for erection of the tank.

The tank is then installed along the lines generally outlined in Australian Patent 579858, which also entails temporarily leaving one panel out. This missing panel would typically be in register with missing rails in the outer frame. If the tank *was being erected under adverse conditions such as a substantial wind, the 4successive tank panels would be immediately clipped to the upper rails of the frame as they were placed in position. Assembly of the tank is completed by successfully threading the metal straps through the loops 18 and fastening them in place. At the appropriate time, as early as possible, any missing rail links in the frame are clamped into position.

In many cases, the tank would be provided with a roof. A suitable frame for such a roof includes three equiangularly spaced tubular legs 52 with upright portions 54 and inclined roof portions 55. The upright portions of the legs may, if desired, form uprights in the frame 12 or may be separately clamped to rails of the frame. The inclined roof portions 55 may be coupled by a peak plate with U bolts, as shown, or by any suitable other connector, e.g. a three pronged "spider", with the prongs received as spigots in the respective tubes 55. Figure 5 shows a fully built tank with the roof 60 in place.

It will be appreciated that the entire installation may be readily dismantled and that the frame 12 in particular may be dismantled by unfastening the clamping devices 25 to separate the rails and uprights.

7 II C1 -8- It has been found that a frame of the form depicted in Figure 1 greatly enhances the empty strength of the tank 10 within. The simple presence of the frame rails in close proximity to the tank walls is sufficient in itself, given the overall circular symmetry, to prevent any significant distortion or translation of the tank wall and still further stability is provided by the multiple clips Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers.

940131,p:\oper\gjn,62518cre.spe,8

Claims (25)

1. A dismantable storage tank assembly comprising: a dismantable tank including a wall defined by a plurality of panel members; a plurality of elongate uprights arranged at spaced intervals about said tank wall; i a plurality of curved rail members interconnecting and detachably secured to each adjacent pair of said uprights, which rail members thereby collectively encircle said tank wall; and means to detachably couple at least some of said uprights and/or said rail P t members to said tank at spaced locations about said tank; wherein said tank assembly may be dismantled by detaching said coupling S" 15 means and separating said uprights, rail members and panel members.

2. A dismantable storage tank assembly according to claim 1 wherein said curved rail members comprise separate rail members between each adjacent pair of said uprights.

3. A dismantable storage tank assembly according to claims 1 or 2 wherein said rail members are detachably secured to said uprights by respective clamping devices which support rail members to each side of each upright. 25

4. A dismantable storage tank assembly according to claims 1, 2 or 3 wherein said rail members encircle said tank substantially in two planes adjacent the top and bottom of the tank.

A dismantable storage tank assembly according to claim 4 wherein said detachable coupling means couple the upper rail members to said tank.

6. A dismantable storage tank assembly according to any preceding claim further comprising respective footplates for said uprights.

7. A dismantable storage tank assembly according to claim 5 wherein each of said footplates includes means to locate the respective uprights on the footplate.

S8. A dismantable storage tank assembly according to any preceding claim wherein said detachable coupling means comprise a plurality of clips which are attached to the rail members and to the top edge of said tank wall.

9. A dismantable storage tank assembly according to claim 8 wherein each of said clips comprises a strap with structures formed to complement said rail members and said top edge of said tank wall, and formed for location thereon by a snap action.

A disma.table storage tank assembly according to any preceding claim further comprising a plurality of encircling straps releasably disposed about said panel members for maintaining said tank wall.

11. A dismantable storage tank assembly according to claim 10 wherein said straps extend through and are located by successive loops pressed from and integral with said panel members.

12. A dismantable tank assembly according to any preceding claim wherein the chord length of curved said rail members is similar to the length of said uprights.

13. A kit for a dismantable storage tank assembly, comprising: a plurality of panel members erectable to define a wall for a dismantable tank; a plurality of similar substantially straight elongate frame members adapted to be arranged as uprights at spaced intervals about said tank wall; i a plurality of similar rail members; -QI -11 means to interconnect and detachably secure said rail members to said uprights so that the rail members curve about and collectively encircle said tank wall, there being a plurality of rail members between each adjacent pair of said uprights; and means to detachably couple at least some of said uprights and/or said rail members to said tank at spaced locations about said tank; wherein said tank assembly may be dismantled by detaching said coupling means and separating said uprights, rail members and panel members.

14. A kit according to claim 13 wherein said curved rail members comprise separate rail members between each adjacent pair of said uprights.

A kit according to claims 13 or 14 wherein said interconnecting means comprise respective clamping devices which in situ support rail members to each side of each upright.

16. A kit according to claims 13, 14 or 15 wherein said rail members are provided to encircle said tank substantially in two planes adjacent the top and bottom of the tank.

17. A kit according to claim 16 where said detachable coupling means are for coupling the upper rail members to said tank.

18. A kit according to any one of claims 13 to 17 further comprising respective footplates for said uprights.

19. A kit according to claim 18 wherein each of said footplatcs includes means to locate the respective uprights on the footplate.

20. A kit according to any one of claims 13 to 19 wherein said detachable coupling means comprise a plurality of clips which are attached to the rail members and to the top edge of said tank wall. _1 IXI1 ii _i~ -12-

21. A kit according to claim 20 wherein each of said clips comprises a strap with structures formed to complement said rail members and said top edge of said tank wall, and formed for location thereon by a snap action.

22. A kit according to any one of claims 13 to 21 further comprising a plurality of straps for releasably encircling and thereby maintaining said tank wall.

23. A kit according to any one of claims 13 to 22 further comprising loops pressed from and integral with said panel members, through which loops the straps extend 10 in situ.

24. A kit according to any one of claims 13 to 23 wherein said rail members are curved and their chord length is similar to the length of said uprights.

25. A dismantable storage tank assembly or a kit, substantially as hereinbefore described with reference to the accompanying drawings. DATED this 31st day of January, 1994. *4 44494 4 4r 4 44r *r 4 44 4 444 444 4 Ii 4 *f I I CREEKS METAL INDUSTRIES PTY LTD By its Patent Attorneys DAVIES COLLISON CAVE 940131,p:\opergjn,6258cre.spe,12