AU2007352883B2

AU2007352883B2 - Plastic tank

Info

Publication number: AU2007352883B2
Application number: AU2007352883A
Authority: AU
Inventors: Manfred Roth
Original assignee: Individual
Current assignee: Individual
Priority date: 2007-04-27
Filing date: 2007-04-27
Publication date: 2012-07-26
Anticipated expiration: 2027-04-27
Also published as: CN101680220A; CN101680220B; MX2009011447A; WO2008135053A1; BRPI0721611A2; AU2007352883A1

Abstract

The invention relates to a plastic tank for the storage of water, feces, and the like, wherein at least two longitudinal chambers are arranged with a space therebetween. Said longitudinal chambers are connected to each other by at least one, preferably two, connecting supports which are arranged transversely to the longitudinal axis of the longitudinal chambers.

Description

Translation from German WO 2008/135053 Al PCT/EP2007/003759 Plastic Tank Description The invention relates to a plastic tank, particularly a plastic underground tank for storing water, excrement, and the like. Thus, the invention relates to a tank s particularly an underground tank - made of plastic, to be used e.g. for storing rainwater, or as an excrement receiving tank. The plastic tank can be fabricated by blow moulding or rotational moulding, and is preferably made of polyethylene. Plastic underground tanks of various designs are known in the art. These known plastic underground tanks are often cylindrical in shape, for stability reasons. 10 They must have adequate strength when subjected to earth pressure in situ. To ensure adequate resistance to earth pressure, prior-art plastic underground tanks often have thick walls. Such plastic underground tanks are usually made by rotational moulding. Plastic underground tanks normally have volumes of approximately 3500 to 6000 L, and most commonly about 5000 to 6000 L. 15 However, there are also cases where tanks of much larger capacity are needed. The diameter of prior-art cylindrical plastic underground tanks is usually about 2 m. To achieve high stability and high earth-pressure resistance, especially for large-volume tanks, double-walled tank designs have also been employed in the art. The production of these plastic underground tanks is time- and material 20 consuming, and is expensive. A further drawback with these containers is their heaviness. If cylindrical plastic underground tanks with a smaller cylindrical diameter are used, then their wall thicknesses can also be reduced. There is, for example, a plastic underground tank, known in the art, which has a relatively small cylindrical 25 diameter, and which is formed as a "tubular ring", so to speak. However, this tank has only a relatively small volumetric capacity. For larger volumes, these -2 underground tanks are unsuitable, because their pressure-stability decreases as their size, and hence their annular opening, increases. Also known in the art are plastic underground tanks consisting of a number of small containers combined to form an intercommunicating container system of normal volumetric capacity. The 5 production of such underground tanks is time- and material-consuming. In contrast, the invention is based on solving the technical problem of how to devise a plastic tank of the type mentioned initially, preferably one with a large volumetric capacity, which can be fabricated in a simple, inexpensive manner using a minimum of time and material, and which can, in particular, be made single-walled whilst 10 nevertheless fulfilling the stability requirements and, above all, any static approval testing requirements. Moreover, compliance with static approval testing requirements must particularly be shown for plastic underground tanks that are to be used as excrement collection tanks or in septic tank installations or the like. To solve the above-mentioned technical problem, the invention provides a plastic 15 tank for storing water, faecal matter and the like, wherein at least two longitudinal chambers which are arranged at a distance from each other are provided, wherein the longitudinal chambers are connected to each other by means of at least one connecting piece which is arranged transversely to the longitudinal axis of the longitudinal chambers, and wherein a dome opening is arranged on at least one 20 connecting piece. In a preferred embodiment of the invention, the inventive plastic tank has only two of the longitudinal chambers. As a variant, the inventive plastic tank can have three of the above-mentioned longitudinal chambers. According to the invention, two adjacent longitudinal chambers can be connected to each other by at least two connecting-pieces running at right angles to the longitudinal axes of the 25 longitudinal chambers. As a variant, two adjacent longitudinal chambers can be connected to each other by just two connecting-pieces. In terms of the invention, "longitudinal chamber" means a hollow chamber in which, in particular, water, rain water, excrement, and the like can be collected. According to the invention, the longitudinal chambers can be arranged parallel, or substantially 30 parallel, to each other. Furthermore, the longitudinal chambers can be identical, or substantially identical to each other, having, in particular, the 06/07/12.va 18280 p2p3p5.2 -3 same shape and/or the same size. Preferably, therefore, the longitudinal chambers also have identical volumetric capacities. "Connecting piece" means a transverse chamber, arranged transversely relative to the longitudinal axes of the longitudinal 5 chambers. Saying that the connecting-pieces, i.e. the transverse chambers, are arranged transversely relative to the longitudinal chambers, means, in particular, that the connecting-pieces are arranged at right angles, or substantially at right angles, to the longitudinal axes of the longitudinal chambers. It will be appreciated, moreover, that the inventive plastic tank will have at least one opening for filling and 10 emptying it. Preferably the plastic tank is made entirely or largely of at least one polyolefin. Preferably, the plastic tank is made entirely or largely of polyethylene. There is a much-preferred embodiment of the invention, which is characterized in that the longitudinal chambers are circular and/or oval in cross section. Preferably, both of the longitudinal chambers are cylindrical or essentially cylindrical. 15 It is within the scope of the invention that the plastic tank, particularly when installed underground, is installed horizontal. When the tank is in the installed state, the longitudinal chambers are preferably laid with their long undersides on the ground at ground level or below ground level, with the bottom of the installed tank preferably extending along the longitudinal direction of the longitudinal chambers. In this much 20 preferred variant, a plane passing through the central longitudinal axes of the longitudinal chambers will be parallel or essentially parallel to the ground or to the bottom of the pit. Preferably, the longitudinal chambers have a maximum diameter, at right angles to their longitudinal axis, of: not more than 150 cm; or more preferably, not more than 25 130 cm; or even more preferably, not more than 120 cm; or better still, not more than 110 cm. And in a particularly preferred variant of the invention, the longitudinal chambers have a maximum diameter, at right angles to their longitudinal axis, of not more than 100 cm. If the longitudinal chambers are 06/07112,va 18280 p2p3p5,3 4 WO 2008/135053 Al PCT/EP2007/003759 cylindrical in shape, then the above-mentioned diameters are the cylindrical diameter. It is within the scope of the invention that the length of the longitudinal chambers is more than two times, preferably more than three times, and even more preferably more than four times the length of the connecting pieces (i.e. the 5 latters' length perpendicular to the longitudinal axis of the longitudinal chambers). The diameter of the connecting pieces is preferably not greater, or not significantly greater, than the diameter of the longitudinal chambers at right angles to their longitudinal axes. It is within the scope of the invention that the longitudinal chambers of the 10 inventive plastic tank are single-walled. Preferably, the connecting pieces between the longitudinal chambers are also single-walled. In a preferred variant, all the hollow chambers of the inventive plastic tank are single-walled. In contrast to this, as mentioned initially, prior-art large-volume double-walled tanks are expensive to fabricate, and unfavourably heavy. 15 It falls within the scope of the invention that the connecting-pieces form hollow chambers, like the longitudinal chambers. In this regard, the term "transverse chamber" means a connecting-piece designed as a hollow chamber. A particularly preferred variant of the invention is characterised in that at least one connecting-piece forms a hollow chamber, and this hollow chamber in the 20 connecting-piece is connected to at least one longitudinal chamber. In other words, in this variant, the hollow chamber of the connecting-piece is connected to an interior space in at least one longitudinal chamber. Preferably, the connecting pieces constitute hollow chambers. Preferably, a connecting-piece constituting a hollow chamber is connected to both of the adjacent longitudinal chambers and 25 to the interior spaces thereof. It has already been pointed out that, in a particularly preferred variant, all the hollow chambers of the inventive plastic tank are single-walled. Notwithstanding this, the inventive plastic tank nevertheless has a relatively high volumetric capacity of more than 3000 L. This volume relates to the entire holding-capacity of all of the hollow chambers of the plastic 30 tank. The inventive plastic tank preferably has a volumetric capacity of at least 3500 L and is characterised by high pressure-resistance and high earth-pressure resistance.

-5 A preferred variant of the invention is characterised in that it has a dome-type opening on at least one connecting-piece. It will be appreciated that in this case the connecting-piece will constitute a hollow chamber. When a connecting-piece has a dome-type opening, then, as regards the installation-position of the inventive plastic 5 tank, that connecting-piece will preferably, in certain regions thereof, be made as a vertical cylinder with transition radii to the adjacent longitudinal chambers formed on it. A preferred variant of the invention is characterised in that, between the longitudinal chambers, there is arranged at least one connecting-element, which also connects 10 the connecting-pieces to one another. The connecting-element is preferably bonded or welded to the longitudinal chambers, and is preferably also bonded or welded to the connecting-pieces. In a preferred variant, the connecting element is double walled. The connecting element beneficially contributes to increasing the stability of the inventive plastic tank. The connecting-element is preferably a plastic plate 15 connecting not only the longitudinal chambers but also the connecting-pieces to one another. In a preferred variant of the invention, a plastic plate is connected in between the longitudinal chambers, level with the central longitudinal axes of the longitudinal chambers. The plastic plate is preferably bonded or welded to the longitudinal chambers and connecting-pieces. 20; In one variant of the invention, the inventive plastic tank is fabricated by rotational moulding. In another variant of the invention, the inventive plastic tank can be fabricated by blow moulding. The latter method is suitable, in particular, for larger production numbers. The invention further relates, in this regard, to a method for fabricating a plastic tank, 25 wherein a first, smaller tank is fabricated, in a first operation, and then the longitudinal chambers of the smaller plastic tank are severed in two transversely, and already-made longitudinal chamber sections are inserted between the longitudinal chamber halves resulting from the transverse severing, and are connected to the longitudinal chamber halves, so as to form a second, larger, 06/07/12,va 18280 p2p3p5,a 6 WO 2008/135053 Al PCT/EP2007/003759 plastic tank. The first, smaller, plastic tank can be produced by blow moulding or rotational moulding. Then, transverse severing is performed on the small container unit, and the separated container components are joined to already made longitudinal chamber sections, to lengthen the container to the desired 5 volumetric capacity. If, as in the preferred variant, the longitudinal chambers of the smaller plastic tank are connected together by means of a connecting element, then this connecting-element is also severed transversely during the transverse severing of the longitudinal chambers. In a variant of the invention, recesses formed in the bottom of the plastic tank are 10 supported with a filling material. The filling material used is, preferably, extended polystyrene. In a much-preferred variant, the hollow spaces in the inventive plastic tank are subdivided into separate compartments by solid, or partly solid separating walls. The connecting pieces that connect the longitudinal chambers of the plastic tank 15 are preferably cylindrical in shape, at least in some regions. The maximum diameter of the connecting pieces (measured parallel to the longitudinal direction of the longitudinal chambers) is preferably not more than 150 cm, more preferably not more than 130 cm, more preferably still, not more than 120 cm, and even better, not more than 110 cm. In a particularly preferred variant, the 20 maximum diameter of the connecting-pieces (measured in the longitudinal chambers' longitudinal direction) is not more than 100 cm. Preferably, said diameter of the connecting pieces corresponds at least approximately to the diameter of the longitudinal chambers at right angles to their longitudinal direction. 25 Underlying the invention is the realisation that, even with larger volumetric capacities, the inventive plastic (underground) tank has surprisingly high pressure-resistance and earth-pressure resistance. In other words, a tank constructed according to the invention exhibits great stability when subjected to earth-pressure, even though it is made of plastic; and it does not exhibit the 30 initially-mentioned, known drawbacks of the prior art. The inventive plastic tank fulfils the static approval test requirements, e.g. for use as an excrement 7 WO 2008/135053 Al PCT/EP2007/003759 collecting tank. It must be emphasised that this outstanding pressure-resistance and earth-pressure resistance occurs even though, in a particularly preferred variant, the inventive tank, which can be installed underground, is single-walled. For this reason, the inventive tank is favourably light in weight, compared with the 5 double-walled tanks of the prior art. It can be made at a reasonable cost, both by blow moulding and by rotational moulding. A particularly important aspect is that, notwithstanding its relatively large volumetric capacity, the inventive plastic tank can be relatively low in height when in the installed state, due to its being subdivided into at least two longitudinal chambers according to the invention. 10 Therefore, when it is to be installed underground, it only requires a relatively shallow pit, and is therefore relatively cheap to install, because deep pits are markedly more expensive than shallow pits of comparable volume. In other words, only shallow pits are required for a plastic underground tank according to the present invention, enabling considerably cheaper excavation work than that 15 required with the prior art. Particularly favourable are those plastic tanks according to the present invention whose longitudinal chambers or cylindrical longitudinal chambers each have a maximum diameter of not more than 100 cm. These inventive plastic tanks can also be transported, in a particularly space saving manner, e.g. on motor lorries, on railway wagons, or in containers. 20 Obviously the inventive plastic tank can also be set up above ground, singly or stacked. In the latter case, the individual tanks can also be connected to each other. The invention will now be described in further detail, with reference to diagrammatic drawings showing only one example. In the drawings: 25 Fig. 1 is a perspective view of a first form of the plastic tank of the present invention, Fig. 2 is a plan view of the subject-matter of Fig 1, Fig. 3 is a side view of the subject-matter of Fig 1, Fig. 4 is a front view of the subject-matter of Fig 1, 30 Fig. 5 is a perspective view of a second form of the plastic tank of the present invention, 8 WO 2008/135053 Al PCT/EP2007/003759 Fig. 6 is a plan view of the subject-matter of Fig 5, Fig. 7 is a perspective view of a third form of the plastic tank of the present invention, Fig. 8 is a plan view of the subject-matter of Fig 7, 5 Fig. 9 is a side view of the subject-matter of Fig 7, Fig. 10 is a front view of the subject-matter of Fig 7, Fig. 11 is a perspective view of a fourth form of the plastic tank of the present invention, which is to be lengthened to make a larger plastic tank, Fig. 12 is a plan view of the subject-matter of Fig 11, 10 Fig. 13 is a side view of the subject-matter of Fig 11, and Fig. 14 is a front view of the subject-matter of Fig. 11. The Figures show a plastic tank in accordance with the present invention, which, in the example shown, is installed as a plastic underground tank for storing rainwater, excrement, or the like. The plastic underground tank has two 15 longitudinal chambers 1, arranged spaced apart. The two longitudinal chambers 1 are preferably arranged parallel to each other, as in the example; and they are both the same size and shape, in the example shown in the Figures. Preferably, as in the Figures, the longitudinal chambers 1 are circular in cross section and are thus in the form of long, cylindrical chambers 1. The longitudinal chambers 1 20 preferably have a maximum diameter - at right angles to their longitudinal axis - of 100 cm. Thus, the longitudinal chambers 1 are, relatively speaking, not very high; and consequently, when the inventive plastic tank is installed underground, only a shallow pit is required-which is an advantage. It lies within the scope of the invention that the longitudinal chambers 1 can be made single-walled, 25 thereby advantageously reducing the weight of the plastic underground tank. The orientation of the tank as shown in Fig. 1 is the preferred horizontal orientation of the tank in the installed state. In the example shown in Figs 1 to 6, the longitudinal chambers 1 are connected to each other by two connecting-pieces 2, arranged at right angles to the 30 longitudinal axes of the longitudinal chambers 1. The connecting-pieces 2 are 9 WO 2008/135053 Al PCT/EP2007/003759 preferably, as in the example, in the form of hollow chambers (transverse chambers), and the hollow chambers of the connecting pieces 2 are each connected to the interiors of the two longitudinal chambers 1. The two connecting-pieces 2 in Figs. 1 to 6, and the outer two connecting-pieces 2 in 5 Figs. 7 to 10, have a topside section 3 in the form of a vertical cylinder 3. This topside section 3 in the form of a vertical cylinder is connected to the adjacent container areas by transition radii. It is within the scope of the invention that a dome-opening can be arranged on a connecting-piece 2 of this design. In the example shown in Figs. 7 to 10, an additional, central, connecting piece 4 10 is provided. This plastic underground tank, in the example shown in Figs. 7 to 10, has a relatively large volumetric capacity: about 7000 L in the example shown. The plastic underground tank in Figs. 1 to 4, on the other hand, has a capacity of about 5500 L. And the plastic underground tank in Figs. 5 and 6 has a smaller 15 capacity, about 4000 L in the example shown. All of the plastic underground tanks shown in the Figures are relatively large-volume containers. As is shown in all the variants in the Figures - and as is much preferred - the longitudinal chambers 1 project longitudinally beyond the connecting-pieces or outer connecting-pieces 2. In the examples shown, the connecting-pieces 2, 4 20 are connected to the longitudinal chambers 1 at right angles. In the example shown in Figs. 1 to 6, the longitudinal chambers 1 and the two connecting pieces 2 are connected to one another by a plastic plate 5 (see in particular Figs. 2 and 6). This plastic plate 5 is preferably bonded or welded to the longitudinal chambers 1, and also to the connecting pieces 2. In the example 25 shown, the plastic plate 5 is arranged at the level of the central longitudinal axis L of the longitudinal chambers 1. In the variant shown in Figs. 7 to 10, each plastic plate 5 connects two connecting pieces 2, 4, and the longitudinal chambers 1 to one another. Here too, the connection of the plastic plates 5 to the longitudinal chambers 1 and 10 WO 2008/135053 Al PCT/EP2007/003759 connecting pieces 2, 4 is preferably effected by bonding or welding. And in this example too, the plastic plate 5 is arranged at the level of the central longitudinal axis L of the longitudinal chambers 1. In a preferred variant, the container-bottom of the plastic underground tank has 5 recesses (not shown) formed in it, which are filled with ready-made filling material, particularly expanded polystyrene. In this way, the stability and earth pressure resistance of the plastic underground tank can be further increased. A further aspect of the invention is that the interior spaces of the plastic underground tank can be subdivided into compartments by separating-walls (not 10 shown). Figs. 11 to 14 relate to a special variant form of the inventive plastic underground tank and to a preferred method for producing the inventive plastic tank. First, a small container unit (first, smaller, plastic underground tank) is made, as shown in Figs. 11 to 14. The volume and capacity of this small container unit is about 15 3500 L in the example shown. The small container unit has, on each longitudinal chamber 1, two mutually opposite parting-flanges 6 formed thereon, each of which runs around the circumference of the longitudinal chamber 1 concerned. The parting-flanges 6 are preferably located halfway along each longitudinal chamber 1. The longitudinal chambers 1 of the container unit shown in Figs 11 to 20 14 also have reinforcing grooves 7 formed in them, which help strengthen the longitudinal chambers 1 and the plastic tank. After the fabrication of the small container unit shown in Figs, 11 to 14, the two longitudinal chambers 1 are each severed between the parting-flanges 6. Then the two longitudinal chambers 1 are lengthened by inserting prefabricated 25 longitudinal-chamber sections (not shown) between the two separated container halves and then affixing said sections to the longitudinal chamber halves 9, 11 of the container halves. The prefabricated longitudinal chamber sections are preferably inserted between the parting-flanges 6, and are preferably affixed by welding. The length of the longitudinal chamber sections will be chosen 30 according to the desired volume of the resulting plastic underground tank (second, larger, plastic underground tank).

Claims

1. A plastic tank for storing water, faecal matter and the like, wherein at least two longitudinal chambers are arranged at a distance form each other are provided, wherein the longitudinal chambers are connected to each other 5 by means of at least one connecting piece which is arranged transversely to the longitudinal axis of the longitudinal chambers, and wherein a dome opening is arranged on at least one connecting piece.

2. The plastic tank according to claim 1, wherein two connecting pieces are arranged transversely to connecting piece which is arranged transversely 10 to the longitudinal axis of the longitudinal chambers.

3. The plastic tank according to claim 1 or claim 2, wherein the longitudinal chambers and/or the connecting piece(s) have a circular and/or oval cross section.

4. The plastic tank according to any one of claims 1 to 3, wherein the 15 longitudinal chambers have a greatest diameter of no more than 150cm, transversely to their longitudinal axis.

5. The plastic tank according to claim 4, wherein the greatest diameter is no more than 100 cm.

6. The plastic tank according to any one of claim 1 to 5, wherein the 20 longitudinal chambers are single-walled.

7. The plastic tank according to any one of claims 1 to 6, wherein at least one connecting piece is configured as a hollow chamber and wherein the hollow chamber is connected to at least one longitudinal chamber.

8. The plastic tank according to any one of claims 1 to 7, wherein a 25 connecting element is arranged between the longitudinal chambers, which connecting element connects the longitudinal chambers and the connecting pieces to each other.

9. The plastic tank according to any one of claims 1 to 8, produced by a blow moulding process or by a rotary process. 30

10.A plastic tank, composed of two halves of a transversely divided first small plastic tank according to any one of claims 1 to 9, wherein the two halves are enlarged to form a second larger plastic tank according to any 08/03/11, va 18280 claims.doc, II - 12 one of claims 1 to 9 by additionally inserted longitudinal chamber sections. 08/03/11. va 18280 claims.doc, 12