GB2108188A - Storage tank - Google Patents

Abstract

The tank consists of a plurality of sheets (2, 4) formed to desired shapes, engaging means (14, 16) on said sheets, arranged so that said sheets in co-operating and engaging relationship form a shell and applied to said shell (e.g. by means of edging 20) a bottom plate (12) to form a box-like structure. A pre- formed plastics material lining may be applied to the structure, or a plastics material lining (22) may be applied to the structure by rotational moulding so as to bond the shell and so as to bond the shell to the bottom plate, the lining extending inwardly of the shell so as to form an apertured top for the structure. <IMAGE>

Description

SPECIFICATION Storage tank This invention relates to storage tanks, and more particularly but not exclusively to storage tanks for holding liquids.

The invention aims to provide a method of producting a storage tank, which method is simple and economical to perform and which produces a tank which is more acceptable than tanks made in conventional manner.

According to one aspect of the present invention there is provided a method for use in the production of a storage tank, the method comprising the steps of cutting or forming a plurality of sheets to a desired shape and size and forming sheet engaging means on said sheets, arranging said sheets in co-operating and engaging relationship so as to form a shell, securing a bottom plate to said shell, so as to form a box-like structure.

The method may include a still further step of applying a lining to the interior of ths structure so as to bond said shell and said bottom plate together, said lining extending inwardly of said side walls so as to form an apertured top for said structure.

The method may include the additional step of forming edge pieces for application to the sheets, some of said edge pieces receiving said sheets and said bottom plate in the formation of the box-like structure.

The lining for the box-like structure will preferably be applied by rotational moulding.

According to a second aspect of the present invention, there is provided a storage tank comprising side and end walls and a bottom plate, said side walls being secured together by means formed integrally with said walls, said bottom plate being secured to said side and end walls by means of a plurality of edge pieces.

Preferably, each side and end wall will consist of a sheet having at least one outturned edge and one roll-formed edge, sai out-turned edges and said roll-formed edges co-operating together to secure said side and end walls together.

Said edge pieces will preferably comprise roll-formed members some at least of which are capable of receiving said side walls and said bottom plate so as to secure said side walls to said bottom plate.

Said storage tank may have a lining therein, said lining being applied by rotational moulding so as to bond said side and end walls to each other and to said bottom plate. Preferably said lining will extend inwardly of said side walls so as to form an apertured top of said storage tank.

Alternatively a preformed lining may be inserted in said tank.

Preferably, said lining will consist of a plastics material.

In order that the invention may be more readily understood, an embodiment thereof will now be described by way of example, reference being made to the accompanying drawings, in which: Figure 1 is a perspective view of a storage tank according to the invention; Figure 2 is a side elevation of the tank of Fig. 1; Figure 3 is an end elevation of the tank of Figs. 1 and 2; Figure 4 is a plan view of the tank of Fig.

2; Figure 5 is a sectional elevation, to a larger scale, taken on line V-V of Fig. 4; and Figure 6 is a diagrammatic representation of part of the storage tank of Figs. 1 to 5.

Referring to the drawings, and firstly to Figs. 1 to 4, a storage tank S comprises side walls 2 and end walls 4, a top 6 having an aperture 8 and strengthening rib 10 and a bottom 1 2 (Fig. 5). The side walls 2, end walls 4, and bottom 1 2 are each formed of galvanised sheet metal or other similar material. The side walls 2 and end walls 4, referring now to Fig. 6, are each generally Lshaped as shown. One edge of each sheet is bent outwardly as indicated by reference numerals 14, and the other edge is roll formed to a generally U-shape as indicated by reference numerals 1 6. The bent portions 14 and the U-shaped portions 1 6 are formed at pre-determined distances from the corners of said sheets forming the side walls 2 and end walls 4, and are formed integrally with the sheets.As will be seen from Fig. 5, the portions 14 and 16 engage in co-operating relationships so as to secure the side and end walls together, the side and end walls being so secured by sliding the portion 14 of one sheet into the portion 1 6 of an adjacent sheet, thus forming ribs 2A and 4A on the side walls and end walls respectively, this resulting in the formation of a shell 1 8.

A plurality of edge pieces 20 of mild steel or similar material, are roll formed to the shapes shown in Fig. 5 such that they are capable of receiving the vertical side walls 2 and end walls and such, in the case of the lower edge pieces that they are also capable of receiving the horizontal bottom plate 1 2.

By means of the edge pieces 20 the side and end walls 2 and 4 are secured together as shown in Fig. 5. Each of the edge pieces 20 are mitred as will best be seen from Fig. 4. In the case of the upper (in the drawing) edge pieces 20, horizontal portions thereof extend inwardly to form part of the top of the tank.

Such a tank may be used for storage of nonliquid material or liquids of high viscosity.

To adapt the tank for storage of liquids, a lining 22 (Fig. 5) may be applied to the interior of the tank, said lining including a free-form neck 24 to constitute the aperture 8 in the top 6. The lining 22 is applied to the tank by a rotational moulding process, and it will be appreciated that the remainder of the top 6 of the tank is formed during this moulding process. The material of the lining is preferably a synthetic plastics material.

As well as providing a lining for the storage tank, the lining 22 also serves as a bond to permanently secure together the side walls 2, end walls 4 and the edge pieces 20 such that the tank is rigid or semi-rigid and leakproof.

The lining 22 will be applied to a desired thickness, of the order of 0.125 inches (3 to 4mm), although it will be appreciated that such thickness may vary.

The method for constructing and forming the storage tank is as follows.

A plurality of sheets of galvanised metal or other similar material are cut to size, and the four corners of each sheet are notched. The edges of the respective sheets are formed with the outwardly extending portions 14 and the U-shaped portions 16, whereafter the sheets are bent at right-angles at predetermined distances from the edges of said sheets. The outwardly extending portions 14 are then slid into the U-shaped portions 1 6 of adjacent sheets so as to form an open-ended shell as shown in Fig. 6.

The edge pieces 20, formed by roll-forming as mentioned above, are then applied to the bottom 1 3 of the tank by snapping or pushing the horizontal portions of the pieces 20 onto the edge of the bottom 1 2. The open ended shell is then snapped or pushed into the vertical portions of the edge pieces 20, whereafter the other edge pieces 20 are applied to the upper extremities of the shell by engaging said upper extremities in the vertical portions of said other edge pieces 20. Thus there is formed an assembled box or structure which may be used by itself or which may form the basis of the storage tank S.

To apply the lining 22 to the box or structure, the box or structure is placed in a jig and a moulding lid is clamped to the open top of the box or structure, whereafter the lining is applied by rotational moulding, such rotational moulding simultaneously forming the top 6, aperture 8 and strengthening rib 10.

After moulding, the moulding lid is removed and the storage tank S is complete.

If desired, spacer plates may be applied to the sides and ends of the storage tank to increase the size of the tank. Such spacer plates will each consist of sheet metal and two opposed side edges will be formed with the portions 14 and 1 6 similar to those on the side and end walls, and where such spacer plates are used, the side and end walls 2 and4 will be slidably connected to said spacer plates.

It will be appreciated that the storage tank need not be of the shape shown in the drawings, and that the storage tank may have more than four sides.

A storage tank according to the invention is relatively simple and easy to construct, and hence economical, yet the storage tank possesses the necessary strength and impermeability of conventionally formed tanks, in that a tank according to the invention possesses the strength of a conventional tank, yet is only approximately half the weight of such a conventional tank. These features cannot be equalled in a conventional plastics tank without steel reinforcement.

Finally, instead of the lining being applied by rotational moulding, a preformed plastics material lining may be inserted into the tank.

Claims (13)

1. A method for use in the production of a storage tank, the method comprising the steps of cutting or forming a plurality of sheets to a desired shape and size and forming sheet engaging means on said sheets, arranging said sheets in co-operating and engaging relationship so as to form a shell, securing a bottom plate to said shell, so as to form a box-like structure.

2. A method according to Claim 1, including the further step of forming edge pieces for application to the sheets, some of said edge pieces receiving said sheets and said bottom plate in the formation of the box-like structure.

3. A method according to Claim 2, including the additional step of applying a lining to the interior of the structure so as to bond said shell and said bottom plate together, said lining extending inwardly of said side walls so as to form an apertured top for said structure.

4. A method according to Claim 3, wherein said lining is applied by rotational moulding.

5. A method according to Claim 2, including the additional step of inserting a preformed lining in said structure.

6. A method for use in the production of a storage tank substantially as herein described.

7. A storage tank comprising side and end walls and a bottom plate, said side walls being secured together by means formed integrally with said walls, said bottom plate being secured to said side and end walls by means of a plurality of edge pieces.

8. A storage tank according to Claim 7, wherein each side end wall consists of a sheet having at least one out-turned edge and one roll-formed edge, said out-turned edges and said roil-formed edges co-operating together to secure said side end walls together.

9. A storage tank according to Claim 8, wherein said edge pieces comprise roll-formed members some at least of which are capable of receiving said side walls and said bottom plate so as to secure said side walls to said bottom plate.

1 0. A storage tank according to any of Claims 7 to 9, wherein said storage tank has a plastics material lining therein, said lining being applied by rotational moulding so as to bond said side and end walls to each other and to said bottom plate.

11. A storage tank according to Claim 10, wherein said lining extends inwardly of said side walls so as to form an apertured top of said storage tank.

1 2. A storage tank according to any of Claims 7 to 9, including a pre-formed plastics material lining.

13. A storage tank substantially as herein described with reference to and as illustrated in the accompanying drawings.