DE9416968U1 - Thermoformed plastic tank - Google Patents

Description

DlPL-ING. ULRICH KINKELIN PATENT ATTORNEY EUROPEAN PATENT ATTORNEY 71065 SINDELFINGEN * WEIMARER STR. 32/34 * GERMANY TELEPHONE 07031/871501 * FAX 07031 / 878572

Date: October 24, 1994

My reference: 12 958

Applicant:

DUROtherm Kunststoffverarbeitung GmbH, Industrial Area, 72221 Haiterbach

PLASTIC TANK DEPRESSED

The invention relates to a tank deep-drawn from plastic, at least substantially deep-drawn, according to the preamble of claim 1.

Such tanks are used in particular for rainwater use as cisterns. The collected rainwater is preferably used for watering gardens and flower beds. This saves valuable and treated tap water. The rainwater tanks can be set up freely outdoors or in basements, or installed in the ground.

The rainwater tanks are preferably made of glass fiber reinforced plastic and essentially have a rectangular or box-shaped design with large side walls. When producing tanks deep-drawn from plastic, these large side surfaces cause difficulties in terms of a uniform material thickness, which should prevail over the entire side wall or side surface. Furthermore, the above-mentioned forms of rainwater tanks have a large surface area, which requires an increased material requirement.

12958&THgr;1 ,SAT 24 October 1994 20:47 3 287 O

The object of the invention is to create a tank with a large capacity while at the same time keeping the tank surface small.

The invention solves the problem with the subject matter of the main claim.

The truncated pyramid shape of the half shells, which have a number of corners of at least five, creates half shells that approximate a hemisphere. This allows a substantially uniform reduction in the wall thickness to be achieved during the deep-drawing process, which can also have high strength properties in their final shape. By making the half shells approximate the shape of at least substantially regular truncated pyramids, it is also possible to create an approximation of a box shape, the base of which can hold a large amount of water. By making such a compromise between a hemispherical shape that is ideal for the deep-drawing process and a rectangular shape that can hold the most water on the base above it, a relatively large capacity of the water tanks can be achieved with a small or small tank surface.

By means of the features of claim 2, a greater approximation to the hemispherical shape can be achieved.

Due to the features of claim 3, the circumferential stress acting on the respective connecting edge of the half-shell can be absorbed by the essentially parallel arrangement to the geometric longitudinal axis. The base sections are arranged at a certain angle to each other depending on the n-corner shape of the half-shell. These angles can be expanded under the influence of the circumferential stress. Only tensile stresses occur, which can be absorbed by the n-corner base without damaging or impairing the shape. The base can therefore take on the function of a barrel hoop.

With the features of claim 4 it can be achieved that no large side surfaces are created, which lead to a box-shaped design of the tank.

1285831.5&Lgr;&Mgr; 24 October 190420:473 2870

With the features of claim 5, a harmonious and aesthetic design of a half-shell can be created in which the n-gon shape of the truncated pyramid flows into the n-gon shape of the base, with the corners lying in a line.

With the features of claim 6, a higher absorption of the circumferential stress can be achieved by the base sections, which are preferably designed in a straight line. This makes it possible to create a closer approximation to the barrel strip function and to use its advantages. With the features of claims 7 and 8, a high degree of rigidity of the half shells can be achieved in a structurally simple manner. In particular in the area where the water surface is the largest and thus the pressure acting on the outer walls is the greatest, the stiffening ribs have their greatest width. This means that the side walls of the truncated pyramids can be stiffened at the same time, so that they are not bulged outwards by the water pressure formed in the water tank.

The features of claim 9 ensure that the upper half-shell retains its shape when installed in the ground. The flat side surfaces of the upper truncated pyramid serve as supports for the upper surface of the truncated pyramid in order to prevent the upper surface of the truncated pyramid from being pressed inwards or sinking towards the bottom of the tank. This allows the forces exerted by the earth masses above to be absorbed and held.

With the features of claim 10, two essentially symmetrical half-shells can be created, which have an appealing and aesthetic overall impression in the marked state.

With the features of claim 11, the second half-shell can be designed as a lower half-shell which has an at least substantially flat or level support surface on which the tank can be placed.

With the features of claim 12, the forces acting on the outer walls of the half-shells can be evenly absorbed by the advantageous design of the stiffening ribs. Furthermore, an attractive design is retained. 129S6B1SAM October 24, 1604 20:47 3 287 O

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With the features of claims 13 and 14, the upper and lower half shells can center themselves relative to one another during assembly due to the design of the rims, so that both half shells can be firmly connected to one another along a common longitudinal axis. At the same time, the connecting edges cannot slip inwards due to the rims of the upper and lower half shells, which are bent upwards or downwards in pairs. The connecting edges can thus be fixed radially in a certain position relative to the longitudinal axis, in which the two connecting edges lie at least essentially parallel to one another.

With the features of claims 15 to 17, the connecting edges can abut one another with their radial ring area and seal the tank in a liquid-tight manner. The connecting edges can have a circumferential groove formed by the ring areas, which are arranged in mirror image to one another when the connecting edges abut one another. A sealing ring, e.g. made of rubber, or another type of sealing element, e.g. a pasty mass such as silicone, can be inserted or introduced into this tubular circumferential groove. When the two half-shells are attached to one another using connecting means, which can be done in particular using screw connections, this tubular circumferential groove forms a liquid seal or other detachable fastenings.

With the features of claim 18, the forces acting on the second truncated pyramid surface during installation in the ground can be absorbed by one or more standpipes, so that the tank can be installed in the ground free from external forces.

With the features of claim 19, a volume taken up by the standpipe, which would be lost to the tank in its holding volume, can be reduced to a small extent by allowing the liquid held in the tank to flow into the standpipe via communication holes. As a result, the holding volume can be reduced by the wall thickness of the standpipe.

With the features of claim 20, one or more tanks can be connected in series or parallel to a main tank. This allows the downstream

1295S81 .SAM M. OWeOW 1904 20:47 3 2S7 O

Tank can be used as an overflow if the first or upstream tank is completely filled with rainwater. It can also be provided that connections in the lower area of the tank allow several neighboring tanks to be filled evenly and/or evenly drained. The connecting pipes can also advantageously be provided with shut-off valves so that the tanks can be completely emptied one after the other.

With the features of claim 21, an inlet connected to the gutter may be sufficient to fill the tank(s). This may also enable simple cleaning or filtration of the rainwater from leaves, protective particles or the like by interposing a filter system between the gutter pipe and the inlet of the tank.

The invention will now be described using a preferred embodiment. The drawing shows:

Fig. 1 is a schematic side view of a tank deep-drawn from plastic,

Fig. 2 a top view of the tank according to Fig. 1

Fig. 3 is a schematic sectional view along the line l-l in Fig. 1,

Fig. 4 an enlarged view of section X in Fig. 1

Fig. 5 is a schematic representation of a standpipe in a tank.

Fig. 1 shows a tank 11 made of plastic that is used to collect rainwater. The tank 11 is preferably made of glass fiber reinforced polyester and has a water-resistant coating. The tank 11 can be installed both in the ground and freely in a basement or outside area.

129S6B1 SAM 2&Lgr;. OWai*f 1904 20:47 3 MT 0

The tank 11 has an upper half-shell 12 and a lower half-shell 13, which in the assembled state have a common vertical longitudinal axis 14.

The lower half shell 13 has the shape of a regular truncated pyramid 25, which is octagonal in shape, for example. The small truncated pyramid surface opposite a base surface of the truncated pyramid is designed as a flat standing surface 16 and rests on a support surface, e.g. the basement floor or soil. The steeply rising side surfaces 27 of the truncated pyramid 25, which are formed from stiffening ribs 18 and the wall area or mirror 19 in between, are connected to a surrounding base 21, which runs essentially parallel to the geometric longitudinal axis 14. The base 21 is also octagonal in shape and the corners 39 of the side surfaces 28 of the truncated pyramid 25 flow smoothly into the corners 39 of the base 21. At the upper end of the base 21, a radially outwardly directed lower connecting edge 22 is arranged, which is arranged at right angles to the longitudinal axis 14.

The upper half-shell 12, which is arranged as a mirror image of an equatorial line 23 of the tank 11, rests with an upper connecting edge 24 of the upper half-shell 12 on the lower connecting edge 22 of the lower half-shell 13. The upper connecting edge 24 is again connected to a base 21 parallel to the longitudinal axis 14, which merges into the essentially steeply arranged pyramid side surfaces 28 of the first truncated pyramid 25. The side surfaces 28 are formed from the stiffening ribs 18 arranged in the corners 39 and the mirrors 9 arranged in between. This first truncated pyramid 25 with flat side surfaces 28 is connected to a second truncated pyramid 26 with flat side surfaces 28, which closes the upper half-shell 12 with a horizontally running end surface 27. The stiffening ribs 18 are wider in the first truncated pyramid 25 at their base-side end area than the intermediate and embossed wall area or mirror 19. As the steepness of the truncated pyramid 25 increases, the stiffening ribs 18 narrow towards the corners 39, so that at the same time the embossed wall area or mirror 19 becomes larger, up to the transition from the first truncated pyramid 25 to the second truncated pyramid 26.

I2958B1XAM 24. OJdefeer 1994 20:47 3 267 0

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12 958

In the second flat truncated pyramid 26, both the stiffening ribs 18 and the mirror 19 taper, whereby the degree of taper of the stiffening ribs 18 is less than the taper in the first truncated pyramid 25.

The base 21 and the connecting edge 22, 24 arranged essentially at right angles to it can absorb the effective circumferential stresses due to their arrangement without any significant deformation of the first truncated pyramid 25. The circumferential stresses can cause the angle enclosed between the base sections to be at least partially stretched, but the degree of stretching is greatly minimized by the circumferential connecting edge 22, 24. This essentially maintains the octagonal shape of the truncated pyramid base.

The upper front surface 27 has an inlet 32 through which rainwater can flow into the tank 11, for example from a gutter. The front surface 27 has a second opening or a nozzle 33 to which a pump for extracting the rainwater can be connected. This pump can have a suction pipe that extends essentially to the bottom area of the tank 11, so that the tank 11 can be completely emptied except for a small bottom area, so that the deposited impurities are not sucked out and lead to blockages. Connection nozzles 36 for a neighboring tank are provided on the side surfaces 28 of the first truncated pyramid 25 of the upper and lower half shells 12, 13. This can create an overflow into the neighboring tank when the first tank is full. By connecting the tanks 11 via connecting pieces 36 in the lower half shell 13 (not shown), the tanks can be emptied simultaneously. In addition, water can be removed from all tanks 11 using just one pump.

The connecting edges 22, 24 have protruding rims or rim regions 37, 38 at their outer end region, which are angled upwards or downwards at an angle α relative to the horizontally extending connecting edge 22, 24. The two rims 37, 38 associated with one another have a positive and a negative angle α, which, however, have the same angle, so that the two rims 37, 38 lie parallel to one another. The rims 37, 38 of the upper 1235βθ1.5�Agr;λ<:�EEgr;. OfcJotoef 1994 20:473 2

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or lower half shell 12, 13 are arranged in such a way that they are arranged one after the other, protruding upwards and one after the other, according to the number of corners 39. This makes it easy to assemble the truncated pyramid, especially with an even number of corners. When assembling the upper and lower half shells 12, 13 or when placing the upper half shell 12 on the lower half shell 13, the upper half shell 12 can center itself with the lower half shell 13, i.e. the brims 37 of the upper half shell 12 come into contact with the brims 38 of the lower half shell 13. Due to the brims 37, 38 protruding one after the other, one upwards and one downwards, the individual sections of the connecting edges 22, 24 cannot slip inwards. The connecting edges 22, 24 automatically come into contact parallel. Subsequently, the connecting edges 22, 24 are fastened to one another by, for example, screw connections or other detachable connections, so that the upper and lower half shells 12, 13 form a unit.

Fig. 2 shows a top view of the tank 11. The tank 11 has an octagonal basic shape made up of side surfaces of equal length. The walls of the base 21 and the associated side surface 28 of the first truncated pyramid 25 and the adjoining second truncated pyramid 26 have the same solid angle as seen from the geometric longitudinal axis 14, so that the corners or corner areas 39 flow smoothly into one another and have a straight line. In the top view it can be seen that the embossed wall surface or the mirror 19 is narrow at its end pointing towards the base and widens towards the transition from the first truncated pyramid 25 to the second truncated pyramid 26 and then tapers again towards the front surface 27. The design of the mirror 19 is essentially due to the lateral expansion of the stiffening ribs 18, which extend evenly from the corners 39 into the side surface 28 to the left and to the right. The widening of the stiffening ribs 18 towards the base 21 enables better stiffening of the side surfaces, which is necessary due to the larger diameter of the first truncated pyramid 25 in the lower area and the resulting increased circumferential stress.

1295S61 .SAM 24 October 1994 20:47 3 287 0

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The stiffening rib 18 has a smooth transition from the first truncated pyramid 25 with a large steepness of the side surface to the second truncated pyramid 26 with a very small steepness of the side surface 28. The mirror 19 is also adapted to this, so that the circumferential stresses acting radially outwards can be absorbed as tensile stresses by the radially outward-pointing stiffening ribs 18 of the second truncated pyramid. It could also be provided that an additional stiffening rib is arranged centrally to the side surface 28 of the first and second truncated pyramids 25, 26 in order to additionally reinforce the flat mirror surface 19 in the case of larger dimensions of a truncated pyramid, so that bulging outwards due to the water pressure can be prevented.

A front edge 44 which limits the mirror 19 at the top is arranged at a distance from the horizontally extending front surface 27, so that an edge region 46 is formed which extends from the front surface into the second truncated pyramid 26 and which can also have the function of a stiffener. Because a uniformly circumferential edge region 46 is created, the forces can be absorbed evenly, which would not be the case if the front edge 44 extended to the side of the front surface 27.

The connecting edges 22, 24 have rims 37, 38 that protrude upwards and downwards on their outer edge areas. These are arranged alternately upwards and downwards so that they can lie parallel to one another when assembled. These rims 37, 38 can also be provided with a circumferential ring that surrounds the rims 37, 38. This can provide additional stiffening of the tank 11 and at the same time protect the rims 37, 38, which is particularly advantageous when installing underground.

Fig. 3 shows a schematic sectional view along the line !-I in Fig. 1. The side surfaces 28 are at an obtuse angle to one another, the included angle being determined as a function of the number η of corners. The wall thickness of the side surfaces 28 is essentially the same after deep drawing due to the shape of the half-shell approaching the hemispherical shape, so that an upper and lower half-shell 12, 13 is formed which has a uniform 128MBI-SAM M. October 19S4 2O:4T 3 2S7 O

12 958

rigidity. Starting from a corner 39 formed by two side surfaces 28, the stiffening ribs 18 extend evenly into the side surfaces 28 and merge into the mirror 19, which is embossed into the side surface 28. This transition is designed in a step-like manner. The circumferential stresses that occur and act on the side surface 28 can cause the mirror 19 to be curved outwards. The step-like or S-shaped transition from the stiffening rib 18 to the mirror 19 can act as a spring element, at least partially yielding, so that the stress in the corner 39 can be at least partially relieved.

The stiffening rib 18 extends directly into the base 21 and the mirror 19 extends over a step 34 into the base 21 or are delimited by the base 21. The walls of the base 21 and the side walls 28 are arranged at the same solid angle as seen from the geometric longitudinal axis 14. The connecting edge 24 is arranged at right angles to the base 21. This has a circumferential groove 41 (not shown in Fig. 1 and 2), which is described in more detail below. Adjoining the outer edge of the connecting edge 24, the left brim 37 is arranged so as to protrude upwards and the right brim 37 is arranged so as to protrude upwards.

Fig. 4 shows an enlarged view of the detail X in Fig. 1. The base 21 is arranged in an L-shape to the connecting edge 22, 24. This arrangement of the connecting edges on the base 21 allows the circumferential forces that act in this area in the direction of arrow 47 to be absorbed and the tank 11 can be kept stable in its shape. In the middle area of the connecting edge 22, 24, a downwardly or upwardly curved ring area 41 is provided, which has a round, closed cross-section when assembled. A sealing member 42, such as a rubber sealing ring, can be inserted into this ring area 41, which is designed as a circumferential groove, or a sealing compound, such as silicone, can be applied, so that after the upper and lower half shells 12, 13 have been assembled, the two connecting edges 22, 24 close the tank 11 in a liquid-tight manner. The lower connecting edge 22 is adjoined by the downwardly projecting brim 38 at an angle α. The upper connecting edge 24 has an upper downwardly projecting brim 37, the

Vertex angle α is equal to the included angle α. This clearly shows how the upper and lower rims 37, 38, which are preferably flat, can lie parallel to one another and how the upper and lower half shells 12, 13 can center themselves in their common longitudinal axis 14 by the surfaces lying against one another sliding down when the upper half shell 12 is placed on the lower half shell 13.

The fastening of the upper and lower half shells 12, 13 is carried out at the connecting edges 22, 24 by means of a screw connection. It can also be provided that the fastening elements are arranged on the rims 37, 38.

It can furthermore be advantageously provided that the brim is divided into two or four at a connecting edge 22, 24 between two corners, so that it has both an upward and a downward protruding brim.

Fig. 5 shows a schematic representation of a standpipe 29, which is provided inside the tank 11 between the front surface 27 of the upper half-shell 13 and the base surface 16 of the lower half-shell 13. This standpipe 29 forms a brace that can withstand pressure. This is particularly necessary when the tank 11 is mounted in the ground. In this case, large weight forces act on the tank 11 due to the piled-up earth, which the tank 11 cannot absorb, especially when it is not full.

The standpipe 29 can be arranged coaxially or parallel to the common longitudinal axis 14 and is preferably round in cross-section. The standpipe 29 also has communication holes 31 preferably evenly distributed over the surface so that the inside of the standpipe 29 can also be filled with rainwater. It can also be provided that several standpipes arranged symmetrically to the longitudinal axis 14 can be arranged in the tank 11. The standpipe 29 can also be made of fiber-reinforced plastic or of a die-cast material.

12C5S8i .SAM 2A. October 1894 20:47 3 2&bgr;7 &Ogr;

Claims (24)

DIPL-ING. ULRICH KINKELIN PATENT ATTORNEY EUROPEAN PATENT ATTORNEY 71065 SINDELFINGEN * WEIMARER STR. 32/34 * GERMANY TELEPHONE 07031/871501 * FAX 07031 / 878572 Date: October 24, 1994 My reference: 12 958 Patent claims: <&Lgr; 1. Deep-drawn, or at least substantially deep-drawn, plastic tank, with a lower half-shell having a connecting edge at the top, with an upper half-shell, which has a connecting edge at the bottom, with connecting means that connect the two connecting edges together in a watertight manner with outwardly projecting stiffening ribs on both half-shells, characterized by the following features: a) The half-shells (12, 13) have the shape of at least substantially regular truncated pyramids (25, 26) which have a common geometric longitudinal axis (14) which is vertical in the position of use. b) The truncated pyramids (25, 26) have an even number &eegr; of corners (39), where &eegr; is at least five. c) The stiffening ribs (18) are formed in the area of the corners (39). 2. Tank according to claim 1, characterized in that the truncated pyramids (25, 26) have an even number of corners (39), where η is at least six. 3. Tank according to claim 1 or 2, characterized in that an n-corner base (21) is provided beyond the respective connecting edge (22, 24), 129SSA1.5AM 24 October 19W 20:50 3 55 E 12 958 whose walls run at least substantially parallel to the geometric longitudinal axis (14). 4. Tank according to claim 3, characterized in that the height of the base (21) is significantly smaller than the height of the half-shells (12, 13). 5. Tank according to claim 1, characterized in that the walls of the base (21) and the associated walls of the half-shell (12, 13) cover the same solid angle when viewed from the geometric longitudinal axis (14). 6. Tank according to one of claims 3 to 5, characterized in that the stiffening ribs (18) at least substantially do not extend into the base (21). 7. Tank according to one of claims 3 to 6, characterized in that the stiffening ribs (18) become wider towards the base (21). 8. Tank according to one of claims 3 to 7, characterized in that, viewed in terms of solid angle, the stiffening ribs (18) are wider in their base-side end region than the wall regions (19) of the truncated pyramids (25) not embossed by the stiffening ribs (18). 9. Tank according to claim 1, characterized in that the upper half-shell (12) comprises a first truncated pyramid (25) of great steepness and, on top of this, a second truncated pyramid (26) of very small steepness. 10. Tank according to claim 8, characterized in that the truncated pyramid (25) of the lower half-shell (13) corresponds in its steepness approximately to the steepness of the first truncated pyramid (25) of the upper half-shell (12). 11. Tank according to claim 1, characterized in that the underside (16) of the second half-shell (13) is at least substantially flat and the second truncated pyramid (26) has no counterpart there. 12. Tank according to claim 1, characterized in that the outer corners (39) of the truncated pyramids (25, 26) divide the stiffening ribs (18) in half. * &bgr; » a Q S * &bull; * <&Igr;9· * («&bgr;» &bgr;&diams;&bgr; ** &bgr; &bull; * &bgr; 13. Tank according to claim 2, characterized in that the connecting edge (22, 24) has, in accordance with the number η, successive rim regions (37, 38) which protrude upwards and downwards and which are at least substantially flat in themselves, that the positive and negative angles α have the same angular value and that this condition applies to the upper as well as the lower half-shell (12, 13). 14. Tank according to claim 13, characterized in that in the assembled state an upwardly directed brim (37) of the upper half-shell (12) lies on the downwardly directed brim (38) of the lower half-shell (13), then a downwardly directed brim (38) of the lower half-shell (13) on the upwardly directed brim (37) of the upper half-shell (12), etc. 15. Tank according to claim 13 or 14, characterized in that inwardly of the rims (37, 38) the connecting edges (22, 24) have a radial annular region (41) and that the annular regions (41) lie on one another. 16. Tank according to claim 15, characterized in that at least one of the ring regions (41) has a circumferential groove. 17. Tank according to claim 15 or 16, characterized in that a circumferential liquid sealing member (42) is located in the circumferential groove (41) 18. Tank according to claim 1, characterized in that at least centrally and at least one standpipe (29) is provided, which forms a pressure-loadable strut between an inner, upper region of the upper half-shell (12) and an inner lower region of the lower half-shell (13). 19. Tank according to claim 18, characterized in that the standpipe (29) has communication holes (31) in its wall (30). 20. Tank according to claim 1, characterized in that connecting pieces (36) for a neighboring tank are provided in its upper region and/or its lower region. J2S58A1 .SAM 24. Cäobtt 1894 2RSS 3 55 D 12 958 ...... 21. Tank according to claim 1, characterized in that if there are several tanks (11) only one has an inlet (32). 12958&Lgr;1 . SAM October 24th XXA 30:56 3 55 0