AU1213699A - Storage tank - Google Patents

Description

P/00/011 28/5/91 Regulation 3.2

AUSTRALIA

Patents Act 1990

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT

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Name of Applicant: Actual Inventors Address for service is: Westdek Pty Ltd Michael lan Hutson and James Malcolm Avetoom Ellis WRAY ASSOCIATES 239 Adelaide Terrace Perth, WA 6000 *O

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Attorney code: WR Invention Title: "Storage Tank" Details of Associated Provisional Application No(s): PP1361 The following statement is a full description of this invention, including the best method of performing it known to me:- -2-

TITLE

"STORAGE TANK" FIELD OF THE INVENTION This invention relates to a storage tank.

BACKGROUND ART Traditionally, storage tanks have been supplied in a constructed form. Whilst this is acceptable for small storage tanks, the difficulty and cost of transporting a medium to large tank has created a need for an alternative approach for such tanks.

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Australian patent 631410 describes one such alternative, in which tanks are assembled in situ from sheets of material with holes punched therein. The tank is S•constructed in a series of rings stacked one atop the other. Each ring partially overlaps the outside of the ring beneath it to form a vertical wall.

0o•• Patent 631410 describes the need to increase the distance (referred to as 'circumferential displacement') between the holes formed in the sheets of material that form each ring. The circumferential displacement accommodates the slightly increased diameter of each ring compared to the ring beneath it, due to the thickness of the sheets of material.

Whilst providing a useful alternative to preforming the tanks, the need to increase the distance between holes in sheets of adjacent rings complicates the manufacturing process. Indeed, the sheets used in each ring of a tank have different hole spacings, requiring recalibration of the hole punching machinery.

-3 DISCLOSURE OF THE INVENTION It has been discovered that by forming each ring with slightly inclined walls, the need to circumferentially displace the holes in the sheets of material of adjacent rings is eliminated, simplifying the manufacturing process.

Throughout the specification, 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.

In accordance with one aspect of this invention, there is provided a storage tank S° 10 having a wall formed from a plurality of overlapping rings provided vertically upon oo.o°i each other, each ring formed from a plurality of sheets of material, wherein said sheets of material in each ring are inclined such that each ring is frusto-conical.

Preferably, said rings overlap with a narrow end of one ring received within a wide end of an adjacent ring.

ego.oi Preferably, the narrow end of each ring is received within the wide end of the ring above it.

Preferably, each sheet of material has at least one row of holes provided therein adjacent each end thereof, each row of holes being inclined to a line extending transversely across said sheet.

Preferably, the rows at one end of each sheet are inclined and equal and opposite amount to 4U IIle rows at th other end.I I I.

Preferably, the rows are inclined towards the centre of the sheet.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will now be described with reference to one embodiment and the accompanying drawings, in which: Figures 1A, 1B and 1C are plan views of sheets of material in the upper, middle and lower rings of a storage tank according to the embodiment, respectively; Figure 2 is an enlarged view of one end of the sheet of material shown in figure 1C illustrating the inclined rows of holes; Figure 3 is a cross-sectional view of part of the storage tank according to the embodiment illustrating the inclined walls of each ring; SFigure 4 is a plan view of the storage tank of the embodiment; and oooeo S 10 Figure 5 is an exploded view of the roof of the storage tank of the embodiment.

DESCRIPTION OF THE EMBODIMENT The embodiment is directed towards a storage tank 10 formed of three rings 12a, 12b and 12c of sheets of material 14a, 14b and 14c, respectively. The rings 12a, 12b and 12c correspond with the upper, middle and lower rings of the storage 15 tank 10. The rings 12a, 12b and 12c are each formed from eight sheets of material 14a, 14b and 14c, respectively.

Each sheet of material 14a, 14b and 14c is corrugated, with the corrugations extending along each sheet, and has a plurality of holes 16 formed therein. The holes 16 are formed in rows 18a and 18b provided at one end 20a of each sheet, and rows 18c and 18d provided at the other end 20b of each sheet. The remaining holes 16 are provided spaced between the rows 18b and 18c adjacent edges 20c and 20d of each sheet. The rows 18a, 18b, 18c and 18d extend across each sheet.

The rows 18a and 18c are the same in each sheet 14a, 14b and 14c, with a hole 16 provided in each crest of the corrugations.

Similarly, rows 18b and 18d are the same in each sheet 14a, 14b and 14c.

However, the sheets of material 14a, 14b and 14c differ in the pattern of the holes 16 in the rows 18b and 18d and whether further holes 16 are provided adjacent the edge Each sheet of material 14a has only two holes 16 in each of the rows 18b and 18d, and does not have any further holes adjacent the edge Each sheet of material 14b has a hole 16 provided in each crest of the o.

10 corrugations in each of the rows 18b and 18d from the edge 20d to approximately :half way across the sheet and a hole 16 adjacent the edge 20d in each of the rows 18b and 18d, and has further holes 16 provided adjacent the edge Each sheet of material 14c has a hole 16 provided in each crest of the corrugations in each of the rows 18b and 18d, and has further holes 16 provided adjacent the edge The distance between the rows 18a, 18b and the rows 18c, 18d in each of the sheets 14a, 14b and 14c is the same. The rows 18a, 18b and the rows 18c, 18d •of holes 16 being the same distance apart for sheets in each ring avoids the need to adjust the spacing of the hole punching machinery during manufacture of the sheets. Further, the sheets can be used in tanks of varying capacities, reducing the number of types of sheets that need to be produced by a manufacturer.

Although the hole pattern shown in figures iA to iC is all that is required to achieve the necessary strength, if only sheets 14c are made, with intermediate holes 16 at each edge 20c and 20d, any sheet could be used in any ring, further simplifying manufacture and construction.

-6- Each row 18a, 18b, 18c and 18d is inclined to a line extending transversely across each sheet 14a, 14b and 14c. The rows 18a, 18b, 18c and 18d are inclined towards the centre of the sheet at the edge 20c, such that holes 16 in the rows 18b and 18c are further apart at the edge 20d than at the edge 20c. This is shown in figure 2 in relation to a sheet 14c. The amount of inclination required is small and the same for each of the sheets 14a, 14b and 14c. The sheets 14a, 14b and 14c of the embodiment are 3.11m in length, with the distance between the holes 16 in rows 18a and 18c being 2.908m adjacent the edge 20d and 2.904m adjacent the edge 10 Figure 4 shows the tank 10 assembled. Each sheet 14c in the lower ring 12c .oo.

overlaps the sheet to its right such that the holes 16 in the rows 18a and 18c are aligned and the holes 16 in the rows 18b and 18d are aligned. Fasteners such as bolts are provided in the aligned holes.

The sheets 14b in the middle ring are then partially overlapped with the sheets 14c in the lower ring, such that the two lowermost holes 16 in the rows 18a and 18c of the sheet 14b are aligned with the two uppermost holes 16 in the rows 18a and 18c of the sheet 14c beneath it. Further, the further holes 16 intermediate the rows 18b and 18c of the sheets 14c and 14c are aligned so as to receive a fastener.

The ring 12a is constructed atop the ring 12b using the sheets 14a in a similar manner.

It should be noted that the hole patterns shown in figure 4 are reversed compared to those shown in figures la, lb and Ic. This is because figure 4 is shown from the outside of the tank 10, whilst figures la, lb and 1 c are shown from the inside of the tank Each sheet 14a, 14b and 14c in the rings 12a, 12b and 12c is slightly inclined to vertical, as shown in figure 3 in an exaggerated manner, such that each ring 12a, -7- 12b and 12c forms a frusto-conical shape with a narrow end 24 and a wider end 26. The inclination need only be sufficient such that the radius of the narrow end 24 of each ring is smaller than the radius of the wider end 26 of the ring above it by an amount corresponding to the thickness of a sheet 14 of material. This is sufficient to allow the ring above it to be fastened to the outside of the ring without needing to adjust the spacing between the holes in each sheet. Further, the outside diameter of the tank 10 does not increase beyond that of the base of the lower ring 12c.

Figure 5 shows a roof 28 of the tank 10 in exploded form. The roof 28 comprises a truss 30 extending diametrically across the top of the tank 10 and affixed thereto. The truss 30 includes a hollow central post 32 arranged to receive a support ring 34 therein. The support ring 34 is secured to the post 32 via a bolt 36 passing through holes provided in both the post 32 and the support ring 34.

Holes are provided in the support ring 34 at a plurality of spaced apart locations along its length to allow the height of the support ring 34 to be adjusted relative to the truss plurality of panels 38 extend radially from the support ring 34 to the upper edge of the tank 10. The panels 38 have upturned edges 42. Adjacent panels are connected together with a cleat 44. A conical hat 46 sits atop the panels 38 and S 20 is affixed to the support ring 34 using a threaded fixing rod 48. A mesh 50 is provided between the hat 46 and the panels 38 to exclude insects from the inside of the tank It should be appreciated that the scope of this invention is not limited to the particular embodiment described above.

For example, in other embodiments, the rows of holes may be provided slightly inclined away from the centre of each sheet.

-8- Further, the number of holes and rows may be varied according to engineering requirements without departing from the invention.

Additionally, the number of rings in the tank may be varied as required.

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Claims (7)

1. A storage tank having a wall formed from a plurality of overlapping rings provided vertically upon each other, each ring formed from a plurality of sheets of material, wherein said sheets of material in each ring are inclined such that each ring is frusto-conical.

2. A storage tank as claimed in claim 1, wherein each sheet of material has at least one row of holes provided therein adjacent each end thereof, each row of holes being inclined to a line extending transversely across said sheet.

A storage tank as claimed in claim 2, wherein the rows at one end of each sheet are inclined and equal and opposite amount to the rows at the other end. .o

4. A storage tank as claimed in claim 2 or 3, wherein the rows are inclined towards the centre of the sheet.

A storage tank as claimed in any one of the preceding claims, wherein said rings overlap with a narrow end of one ring received within a wide end of an adjacent ring. ooo°

6. A storage tank as claimed in claim 5, wherein the narrow end of each ring is received within the wide end of the ring above it.

7. A storage tank substantially as described herein with reference to the accompanying drawings. Dated this Eighteenth day of January 1999. WESTDEK PTY LTD Applicant Wray Associates Perth, Western Australia Patent Attorneys for the Applicant(s)