STORAGE TANK

FIELD OF THE INVENTION

The invention relates to tanks for storage of a fluid or a liquid. Amongst many possible uses, the tanks find application in the storage of water or liquids containing water. They also find application in the storage of wine.

BACKGROUND OF THE INVENTION

Various types of water storage tanks are known. Their construction can be expensive and/or relatively complex involving riveting, screwing, soldering, or welding of joints, often requiring the tanks to be pre -fabricated and transported to the site of installation in assembled or substantially assembled form. The design and consequently the expense of such tanks is directly related to the hydrostatic pressures the tank must withstand in service. This also applies to such tanks formed from plastics materials. The typically bulky nature of water storage tanks can also make the storage and transport of the tanks problematic. Metal tanks for storage of water and the like are typically fabricated from mild steel to permit the creation of joints with:

• tight bends;

• bends of greater than 90 degrees; and

• bends with tight radii less than three times the thickness of the steel substrate.

The tanks are also fabricated from mild steel to permit:

• curving;

• formation of corrugations ; and/or

• formation of reinforcement ribs in the tank peripheral wall to enhance tank strength.

The use of mild steel and the performance requirements of tanks inherently requires that relatively heavy gauge mild steel sheet be used adding to the weight and cost of the tank.

SUMMARY OF THE INVENTION

In an aspect of the invention there is provided a tank for storing a fluid, the tank having a peripheral wall made from at least two panels each formed from a length of sheet material and arranged in a side by side relationship with one another circumferentially about a central upright axis of the tank, respective of the panels having lower and upper outer edge margins interconnecting opposite longer edge margins of the panel, the longer edge margins of adjacent said panels being substantially vertically orientated and lapping one another to form a joint, each said panel spanning the entire height of the peripheral wall and having a plurality of bends or formations spaced apart from each other across the panel, the bends or formations being substantially parallel to the longer edge margins of the panel and extending from the lower edge margin to the upper edge margin.

In at least some forms, the bends or formations of each panel divide the panel into elongate sections, each of the sections facing the central upright axis of the tank. The joints can be formed exterior to the tank's interior and project in an outward direction from the panels constituting the peripheral wall. Respective of the joints can be secured together by any suitable fastening means including mechanical fasteners.

Typically, the internal angle of respective of the bends or formations of the panels will be constant about the peripheral wall of the tank. The internal angle of the bends or formations can be 120° or greater. In at least some forms, respective of the panels of the tank have a plurality of these bends or formations. The panel(s) can have three of more of the bends or formations. The bends or formations can, for example, be formed by a roll- forming process.

Moreover, in at least some forms, the tank further includes a fluid impermeable liner disposed within the interior of the tank for retaining the fluid in the tank.

In addition, the tank can be provided with a base. The lid and/or the base of the tank can be adapted for engagement with at least some of the joints of the peripheral wall for securing the lid and/or base to the wall. In one or more forms, the lid and/or the base of the tank are provided with formations for interlocking engagement with the corresponding joints.

The peripheral wall of a tank will normally have a substantially circular cross- sectional profile.

In one form, the panels of the tank are fabricated from steel. High tensile steel conforming to at least Class G550 as defined by the current Australian Standard AS1397 (Standards Australia Limited, Australia) can be used.

Embodiments of tanks of the invention can have at least one inlet for passage of the fluid into the interior of the tank and at least one outlet for passage of the fluid from the tank. In addition, a tank embodied by the invention can have an overflow outlet for permitting flow of excess flow from the tank, and may be provided with connection fittings for connection of the tank to inlet and outlet plumbing conduits or inflow pipes and for instance, stopcocks as appropriate for the particular installation. In other forms, a tank can be provided with a single aperture through which the fluid enters, and leaves, the tank.

In another aspect of the invention there is provided a kit for assembly of a tank for storing a fluid, the kit comprising at least two panels for forming a peripheral wall of the tank, respective of the panels being in the form of a length of sheet material having lower and upper outer edge margins interconnecting opposite longer edge margins of the panel, the longer edge margins of the panels being arranged for lapping the longer edge margins of each adjacent said panel to form joints securing the panels together when the panels are arranged in a side by side relationship circumferentially about a central upright axis of the tank such that respective of the longer edge margins are substantially vertically orientated, each said panel having a plurality of bends or formations spaced apart from each other across the panel and spanning the entire height of the peripheral wall, the bends or formations being substantially parallel to the longer edge margins of the panel and extending from the lower edge margin to the upper edge margin.

In another aspect of the invention there is provided a method for assembly of a tank for storing a fluid, comprising: providing at least two panels each in the form of a length of sheet material, respective of the panels having lower and upper outer edge margins interconnecting opposite longer edge margins of the panel, each said panel having a plurality of bends or formations spaced apart from each other across the panel, the bends or formations being substantially parallel to the longer edge margins of the panel and spanning from the lower edge margin to the upper edge margin; arranging the panels in a side by side relationship such that the longer edge margins of adjacent said panels lap and are substantially vertically orientated; and securing the longer edge margins together to form joints joining the panels together, the panels being arranged circumferentially about a central upright axis of the tank and spanning the entire height of the peripheral wall.

The invention also extends to individual components of the tank, including the liner, and the wall panels for forming the peripheral wall.

Accordingly, in another aspect of the invention there is provided a fluid impermeable liner adapted for being disposed in the interior of the tank embodied by the invention to retain the fluid within the tank and for being secured to the peripheral wall of the tank, the liner being dimensioned to span from the lower edge margins to the upper edge margins of the panels forming the peripheral wall.

In another aspect of the invention there is provided a wall panel for forming a peripheral wall of a tank for storage of a fluid, the peripheral wall of the tank comprising at least two said panels, the panel being in the form of a length of sheet material having lower and upper outer edge margins interconnecting opposite longer edge margins of the panel, the longer edge margins of the panel being arranged for lapping the longer edge margins of each adjacent said panel of the peripheral wall to form joints securing the panels together when the panels are arranged in a side by side relationship circumferentially about a central upright axis of the tank such that respective of the longer edge margins are substantially vertically orientated, each said panel being dimensioned to span the entire height of the peripheral wall and having a plurality of bends or formations

spaced apart from each other across the panel, the bends or formations being substantially parallel to the longer edge margins of the panel and extending from the lower edge margin to the upper edge margin.

In another aspect the present invention provides a tank for storing a fluid, the tank having a peripheral wall made from at least two panels each formed from a length of sheet material and arranged in a side by side relationship with one another circumferentially about a central upright axis of the tank, respective of the panels having lower and upper outer edge margins interconnecting opposite longer edge margins of the panel, the longer edge margins of adjacent said panels being substantially vertically orientated and lapping one another to form a joint, each said panel spanning the entire height of the peripheral wall; the peripheral wall has a substantially circular cross-sectional profile; the tank further includes a lid; and wherein the tank further includes a base.

The fluid can be water from a mains water supply, storm water, or for instance waste water. Accordingly, tanks embodied by the invention can be utilized for storage of drinking water or in water retention/detention systems. However, as will be understood, tanks as described herein can also be used to store any liquids for which the tanks are deemed suitable.

Design characteristics of at least some tanks embodied by the invention, particularly the circular profile and joint construction, provide the tank with high strength. The use of high tensile steel also permits the panels of the tank to be fabricated from thinner gauge steel strip. Forming the joints externally of the tank also facilitates ease of assembly, particularly when mechanical fasteners are utilised to secure the joints together. Moreover, the tank construction permits at least some embodiments to be provided at relatively low cost and be readily assembled on site without the need for trained personnel. In addition, at least the panels for forming the peripheral wall of the tank may be essentially "flat packed" facilitating warehousing and transport of the tanks in kit form to the site of installation.

Throughout this specification the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated

element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.

Any discussion of documents, acts, materials, devices, articles or the like that has been included in this specification is solely for the purpose of providing a context for the invention. It is not to be taken as an admission that any or all of these matters form part of the prior art base or were common general knowledge in the field relevant to the invention as it existed anywhere before the priority date of this application.

The features and advantages of the invention will become further apparent from the following detailed description of preferred embodiments.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

Figure 1 is a front view of tank according to an embodiment of the invention;

Figure 2 is a top view of the tank of Fig. 1 ; Figure 3 is a partial perspective view from below of the exterior of the tank of Fig.

1;

Figure 4 is a partial perspective view from above of the tank of Fig. 1 with liner not shown;

Figures 5(a) - (d) show schematic views of a number of joints and joint reinforcement arrangements; and

Figures 6(a) and (b) show further alternative joint arrangements.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

A tank 10 for storage of water is shown in Fig. 1 and Fig. 2. The tank 10 has a peripheral wall 12 comprising a plurality of wall panels 14 respectively formed from a length of sheet material. In the illustrated embodiments, the panels are formed from high tensile steel sheet. The high tensile steel will desirably conform to at least Class G550 as defined by the current Australian Standard AS1397 (Standards Australia Limited, Sydney, Australia). Using high tensile steel permits the use of lighter gauge sheet steel than

conventionally known water tanks. The steel substrate (excluding any protective coating) has a thickness of 0.6 mm, although thinner gauge high tensile steel can also be used. For example, the thickness of the steel can be 0.56 mm or less, or even 0.49 mm or less.

Respective of the wall panels 14 are rectangular in form and thereby have a longer dimension and a shorter dimension. The panels span from a base of the tank (not shown) to the lid of the tank (not shown). More particularly, the panels 14 have edge margins along their outer edges, with the upper and lower ones of the edge margins interconnecting the opposite longer edge margins of the panel, the longer edge margins of respective of the panels being essentially vertically orientated and lapping one another to form joints 16 securing the panels together. In the embodiment shown in Fig. 1, the longer edge margins are turned outwardly at an angle of about 90 ^° forming a flange 17. The flanges 17 of adjacent wall panels 14 are in abutment and are held together by mechanical fasteners in the form of alien key - headed bolts received in aligned apertures provided in the flanges 17 and secured in position by corresponding nuts 20. As such, the joints 16 so formed project at an angle of greater than zero degrees with respect to the peripheral wall and more generally, project in an outward direction from the peripheral wall.

As also shown in Fig. 1, the tank 10 further comprises a fluid impermeable liner disposed in the interior 24 for sealing the tank against leakage of water from the tank. The liner can be formed from any suitable plastics material, and can be a flexible laminated sheet having more than one ply, and/or be fabricated from a co-extruded film. The liner 22 can partially support the hydrostatic pressure exerted by the water when the tank is filled. Moreover, the plastics material from which the liner is formed can be of heavier gauge and/or stronger at the base region of the tank compared to the upper periphery of the tank to withstand the greater hydrostatic pressure exerted by the water at the base region.

The liner incorporates one or more inlet and/or outlet hoses aligned with respective inlet and outlet openings of the tank for passage of the fluid into or out of the tank as applicable. The hose(s) are sealed about the inlet and/or outlet openings of the tank against leakage of the fluid from the tank. Any suitable system for effecting the sealing

connection of the liner can be employed. For example, the hose(s) of the liner can be clamped about inlet or outlet openings of the tank by the connection fittings or be secured to the connection fittings by hose clamps or the like.

As well, or alternatively, hole(s) can be provided in the liner to align with inlet and/or outlet connection fittings of the tank. In this instance, the hole(s) of the liner are sealingly clamped about respective of the inlets and outlets of the tank by the connection fitting(s) against leakage of the fluid contained within the tank in use. The region of the liner about the inlet/outlet hole(s) and/or hoses can also be of a thicker gauge to reinforce the liner in those areas. This can be achieved for instance by heat welding the thicker gauge plastics material in position during the fabrication of the Ii ner. As will be understood, an inlet or outlet hose of the liner can also be formed from the same thicker gauge plastics material.

Although the illustrated tank is provided for the storage of the water (e.g. drinking water/rainwater), the tank can also be used for storage of waste water and other fluids with a high water content. Similarly, tanks embodied by the invention can be provided for storage of other fluids including fluids with low alcohol content such as wine and other alcoholic beverages. In instances where the fluid intended to be stored in the tank contains ethanol or other chemical substances, the plastics material from which the liner is fabricated will be selected to be essentially chemically inert with respect to such substances. The liner can, for instance, be fabricated from a food grade plastics material when the tank is to be used for storage of fluids for human consumption or for use in the manufacture of foods or beverage products.

While not shown in Fig. 1, the liner 22 rests on the base of the tank 10. The upper periphery of the liner is folded over the shorter dimensioned peripheral edge 28 of the wall panels 14, and is clamped to the panels by clips 30 in the form of elongate steel channel sections. However, the clips 30 can be fabricated from any suitable material including high density polyethylene (HDPE) or other appropriate plastics material.

Each of wall panel 14 incorporates a plurality of bends 32 that are spaced apart from one another across the panel. The bends are provided by roll-forming the panels. The flanges 17 of the panels can also be formed by the roll-forming operation. The bends

32 are in the form of creases in the sheet steel from which the panels are formed and extend substantially parallel to the flanges 16 comprising the longer edge margins of the panels and span the entire height of the panels uninterrupted from the bottom of the lower edge margins to the top of the upper edge margins thereof. The bends divide the panel into elongate sections 14a which face the central upright axis of the tank. The number and width dimension of the elongate sections 14a is such that the peripheral wall of the tank has a substantially circular (plan view) cross-section.

Besides providing the overall circular shape of the tank, the bends act to reinforce the peripheral wall against the hydrostatic load exerted by the fluid contained by the tank in use. As can also be seen, the elongate sections 14a are not reinforced between the lower and upper edge margins of the panels by any other transverse ribbing or other transverse reinforcement formations extending crosswise between the panels opposite longer edge margins.

In the embodiment shown, the internal angle of the bends is essentially constant about the peripheral wall 12 of the tank. That is, the internal angle essentially does not alter from one bend to the next. In embodiments of the invention, the internal angle of the bends is at least 120 ^° . The internal angle of respective of the bends can be 157 ^° or greater, or even 167 ^° or greater. Moreover, tanks embodied by the invention can for example have a peripheral wall 12 formed by 2, 3, 4 or even more wall panels 14. As best seen in figure 4, the joints 16 are reinforced by reinforcing means in the form of elongate steel strips 34 held longitudinally in abutment against the flanges 17 of the wall panels 14 by the mechanical fasteners. The tank 10 shown in the figures is provided with opposing reinforcing strips along each side of respective of the joints. However, in some embodiments, reinforcing strips 34 may only be provided along one side of each joint as schematically illustrated in Fig. 5(a). Alternatively, reinforcing means in the form of elongate channel sections that clamp the abutting flanges together between the legs of the sections and are secured in position by the mechanical fasteners can be used as schematically illustrated in Fig. 5(b). In such embodiments, a single channel section extending from the base to the lid of the tank 10 can be provided for each joint. In other embodiments, a plurality of channel sections can be provided along

respective of the joints. Typically, there will be essentially no protrusion of the joints 16 of a tank embodied by the invention into the interior of the tank, the interior being defined by the peripheral wall of the tank.

In yet other embodiments, a reinforcing strip in the form of an elongate angle or T- section can be utilised, the section being disposed in the interior of the tank flush against the interior surface of the peripheral wall with an elongate portion of the section extending into the joint such that the section only minimally intrudes into the tank's interior.

Further examples of joints 16 and joint reinforcing arrangements that can be utilised are illustrated in Fig. 5(c) and 5(d). As shown, the flange 17 of one wall panel can lap the flange 17 of an adjacent panel to form a male-female joint. A channel section reinforcing strip as described immediately above can then be used to retain the flanges in clamped engagement (see Fig. 5(b)). While particular forms of male-female joints are shown, it will be understood the invention is not limited thereto and any other arrangement whereby the flanges 16 engage in a suitable male- female joint system can also be employed.

Further examples of joints 16 are shown in figures 6(a) and 6(b). In these examples, flanges 17 interlock to resist being pulled apart. Fasteners may be passed through these joints to provide increased joint strength.

The lower region of the joints 16 of the peripheral wall can also be reinforced to a greater level than the upper region of the tank to account for the greater hydrostatic load exerted on the lower region of the wall in use. This can be achieved by locating mechanical fasteners as described above closer together at the lower region of the joints or for example, using heavier gauge reinforcing strips or channel sections or the like at the lower regions of the joints. In addition, although the tank 10 shown in Figs. 1 - 4 includes the use of fasteners to secure the joints together, suitable adhesives may be used in the absence of any such fasteners. In this instance, the adhesive(s) may be used in combination with a male— female joint arrangement as described above.

The base and lid of the tank can be formed from any gauge and class of steel deemed suitable. In at least some forms, the base and lid will also be fabricated from high tensile steel. The base can, for instance, be formed from the same gauge thickness as the

wall panels 14 of the tank. In addition, in at least some embodiments, the base and lid are adapted for engagement with the joints to secure the lid and base to the peripheral wall. For example, the base and the lid can be provided with formations for inter-locking reception of respective of the joints. These formations can be in the form of recesses provided by cut-outs in the periphery of the base and/or lid that are dimensioned to receive the joints in frictional engagement. In this instance, the peripheral margins of the lid interposed between the recesses can be angled downwardly for reception of the joints by the recesses. To prevent inadvertent loss of the lid from the tank in high winds, elongate fasteners can be inserted through respective of the joints 16 over the outer periphery of the lid. As will be understood, the lid can be slightly con vexed or bowed to inhibit pooling of rainwater on the lid in use. Moreover, the peripheral margins of the base can be bent into an appropriate form or angle for interlocking frictional reception of the lower ends of the joints in corresponding aligned recesses provided in the base. The base can also, for example, be provided with drainage holes to prevent rainwater or other liquids from accumulating in the tank under the liner.

The steel used in the fabrication of the wall panels, base, lid reinforcing members and the like of the tank will normally be pre-galvanised or be provided with a another corrosion resistant metallic or alloy coating. Suitable alloy coatings include those comprising one or more of aluminium, zinc, silicon and magnesium. These components can also be pre-coated with at least one paint layer. The paint finish will desirably be provided on both the outer and inner surfaces of the components.

One or more forms of tanks embodied by the invention can have a storage capacity of at least 500 litres, 750 litres, 1000 litres, 1500 litres, 2000 litres, 5000 litres, 10,000 litres or even 20,000 litres or greater. The height of the peripheral wall can, for example, range from 700mm to about 10m, more usually about 900mm to about 3m and most usually, from about 1.5m to about 2.5m. The diameter of a tank embodied by the invention can be in a range of from 500mm to about 20m, more usually from about 600mm to about 5m and most usually, in a range of from about 650mm to about 3.5m.

The tanks described herein will generally have at least one inlet for passage of the relevant liquid into the interior of the tank and at least one outlet for passage of liquid

from the tank. In other forms, a single aperture can be provided in the peripheral wall of the tank which can be used for the inlet, outlet and overflow of fluid into and from the tank. Connection fittings for connection of the tank to inlet and outlet plumbing conduits, inflow pipes and/or for instance stopcock(s) can also be provided. In one embodiment, the panels forming the wall of the tank are uniformly curved to provide a tank of substantially circular cross section. In this embodiment, no creases are provided in the wall of the tank.

The panels 14 in the unassembled form are shaped to nest one in another when stacked together permitting the panels, lid and base of the tank to be essentially flat packed together in kit form for storage and transport to the site of installation. In addition, the lid and the base of the tank can also be engineered/fabricated differently to one another so that they are not interchangeable to avoid them being mistaken for one another during the construction of the tank.

In this specification, the term "circumferentially" means to surround or encircle. It is not taken to define a tank of circular cross section. As such, tanks of oval, ellipse, or other cross sections are taken to fall within the scope of the invention.

Although the invention has been described with reference to particular examples, it will be appreciated by those skilled in the art that numerous variations and/or modifications can be made. For example, while the embodiments described immediately above are formed from high tensile steel sheet, the peripheral wall, base and lid of embodiments of tanks can be formed from HDPE or other suitable plastics material.

Moreover, the base and lid can be fixedly attached to the peripheral wall 12 by any appropriate means.

All such variations and/or modifications are to be considered within the scope of the invention. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive.