AU705304B2

AU705304B2 - Container floors for large-volume containers

Info

Publication number: AU705304B2
Application number: AU59433/98A
Authority: AU
Inventors: Georg Spindler
Original assignee: Stahlgruber Otto Gruber GmbH and Co
Current assignee: Stahlgruber Otto Gruber GmbH and Co
Priority date: 1997-04-11
Filing date: 1998-03-19
Publication date: 1999-05-20
Anticipated expiration: 2018-03-19
Also published as: AU5943398A; DE29706547U1

Description

AUSTRALIA

Patents Act COMPLETE SPECIFICATION

(ORIGINAL)

Class Int. Class Application Number: Lodged: Complete Specification Lodged: Accepted: Published: Priority Related Art: **o S* oo e *r f Name of Applicant: STAHLGRUBER Otto Gruber GmbH Co.

Actual Inventor(s): Address for Service: PHILLIPS ORMONDE FITZPATRICK Patent and Trade Mark Attorneys 367 Collins Street Melbourne 3000 AUSTRALIA Invention Title: CONTAINER FLOORS FOR LARGE-VOLUME CONTAINERS Our Ref 520984 POF Code: 262266/330920 The following statement is a full description of this invention, including the best method of performing it known to applicant(s): -1- Container floors for large-volume containers The invention concerns a container floor for large-volume containers erected on natural ground to accommodate liquids, suspension or the like.

Foils which can be placed on natural ground for various reasons, e.g. as insulation foils to seal the ground of garbage dumps, to seal or strengthen embankments, to line or seal the ground from artificial waters, in particular of ponds etc. are known, and as a rule they are made of corrosion and abrasion resistant, gas- and liquid-tight plastic foils having a singleor multi-layer construction with or without reinforcements.

Such foils are usually described as geo-diaphragms. It has already been considered to provide large volume containers for the storage of liquids, suspensions or other material mixtures not in the usual manner with a floor platform possibly having a sealing liner, but to use a flexible geo-foil, which lies directly on the natural ground and with its pulled up edge 0 sections is fastened in a gas- and liquid-tight manner to the rigid container walls constructed in the conventional manner or S to their liners. The use of such a geo-diaphragm as container ~floor results in considerable technical and economical advantages, since the flexible as well as within limits pliable 25 foil is capable of following certain ground movements and expensive foundations as well as their anchoring is omitted.

However, the obstacle to the technical application of known geo-diaphragms as container floors has been that the sealing effect of the entire container floor could not be detected or tested by using the usual electric high-tension methods for containers lined this way. In particular the localising of tears, holes, ruptures or the like in a conventional geodiaphragm used as container floor for a large-volume container is not feasible, even when, for example, sensors provided in the ground under the container detect a discharge of the contents of the container.

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On the other hand, from EP-A-0 637 554, for example, it is known to provide large-volume containers used to store liquids, suspensions, bulk material and other media on the inside of their rigid walls and the rigid floor with a rubber liner having at least two layers, in which case the layer facing the interior of the container is electrically non-conductive but otherwise is constructed corresponding to the requirements regarding abrasion- and corrosionresistance and the other rubber layer, joining on the outside, is electrically conductive by having graphite particles embedded in it. To this layer an electrically insulated outer layer is now joined, which is permanently connected with the steel wall of the container and provides an electric insulation. The central, electrically conductive rubber layer has centrally arranged connecting elements to be connected to a central monitoring equipment containing a resistance detector.

S 15 It would therefore be desirable to produce a container floor constructed in the form of a geo-diaphragm, which can be produced in a simple and cost-effective manner and can be tested for imperviousness and leakage positions without o. *,great expense.

20 According to the present invention there is provided a container floor for large volume containers erected on natural ground to accommodate liquids, :suspension or the like, wherein said floor is a flexible corrosion- and abrasionresistant foil or geo-diaphragm, whose edge is joined on all sides pressure-tight to the side walls of the container, which may be lined, and wherein the foil is adapted to sit directly on the ground and includes at least an upper abrasionand corrosion-resistant carrier layer and a lower electrically-conductive layer.

The upper layer is typically electrically non-conductive.

In contrast to the conventional platform-shaped container floors the container floor constructed in accordance with the invention offers a number of advantages with regard to manufacturing costs, servicing and maintenance.

Due to the flexibility and pliability of the foil, small uneven areas of the natural g sund can be compensated for by the foil itself,

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making preparatory work during the erection of a container considerably simpler when compared with the known container constructions. The same applies, for example, to the dismantling or moving of the container, which due to the lack of floor platform no longer needs to be constructed with a rigid shape and whereby the floor can be cut away in a simple manner from the side wall. The provision of an electrically conductive layer provided under the insulating layer makes it feasible to check the container floor after erection for local imperviousness even after considerable operating time. This can be carried out in a known manner by using a mobile testing equipment containing a broom-like detector connected to a hightension source, which is guided manually over the container floor and indicates acoustically even the smallest ruptures in .:i5 the electrically conductive layer.

*e According to a particularly appropriate development of the invention the geo-diaphragm or geo-foil used as container floor comprises several elastomer webs laid next to each other which are joined with each othler at their edges, whose both layers are constructed from sulpho-chlorinated polyethylene on polymer base (CSM) and are chemical, thermal and abrasion resistant, while the thickness of the top layer is approx. 2 mm and the thickness of the bottom electrically conductive layer is 5 approx. 1 mm. Due to the electrical conductivity of the bottom layer of the diaphragm small pores, tears, mechanical damages and loosening of the edges of the diaphragm can be detected by means of such a high-tension test (test voltage 20 kV).

Usefully the individual webs have a length of 20 m and a width of 1.40 m, while both longitudinal edges of each web are tapered to enable a mutual overlapping bonding by means of a reactive adhesive made of chloroprene caoutchouc on polymer base. At the same time the overlapping zones of the individual elastomer webs need not be mechanically roughened to achieve a durable and high-strength joint.

The foils according to the invention are used preferably as container floors for large-volume containers for orepreparation plants, for example for concentration, storage and hydrolisation containers erected on sandy grounds.

Useful executions and developments of the invention are indicated in the sub-claims.

Further peculiarities and advantages of the container floor according to the invention become apparent from the following description of the embodiments illustrated in the drawings.

They show in: Fig.l a single web of the foil according to the invention, in cross-section, Fig.2 a cut-out from a container floor with several single webs joined with each other at the edge, Fig.3 a section through the bottom part of a container side wall with the foil fastened to it.

8000 The elastomer web 1 illustrated in Fig.l is constructed from a top layer 2 which is particularly resistant to abrasion and "00" corrosion and a thinner bottom layer 3 which is electrically conductive, while both layers 2, 3 are joined firmly to each 5 other in a continuous manner. Both layers are made of sulphochlorinated polyethylene on polymer base (CSM) and in the embodiment illustrated have a total thickness of 3 mm, wherein the thickness of the top layer 2 is approx. 2 mm and of the electrically conductive bottom layer 3 approx. 1 mm. Both longitudinal edges 4, 5 of the elastomer web are tapered evenly towards the end, wherein, as illustrated, the width of the electrically conductive bottom layer is smaller than that of the top layer 2.

The cut-out from a container floor illustrated in Fig.2 shows a perspective sectioning of three elastomer webs la, ib, ic the edges of which are bonded with each other overlapping in the manner illustrated. In this case it is important that the

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longitudinal edges of the electrically conductive bottom layers also overlap each other, thus ensuring an electrically conductive and upward insulated layer over the entire surface of the container floor. The joining of the tapered edge zones of the elastomer webs la, Ib and ic is carried out appropriately by cold bonding by means of a reactive adhesive of chloroprene caoutchouc on polymer base. To obtain a very strong and durable bonded joint the overlapping zones of the need not be roughened mechanically.

As this can be seen from Fig.3, a container wall 7 made of steel, which is supported by a concrete substructure 6 sunk into the ground, is provided on the inside wall, for example, with a conventionally sealing lining 8 made of suitable plastic material or rubber. On the inside of this liner 8 the container floor 9 constructed, for example, in the manner shown in Fig.2, is joined fluid-tight via an upwardly bent edge 10 by means of a suitable cold adhesive. The container floor 9 lies on a large S area on the ground constructed, for example, by a layer 11 of sand. At the end of the upwardly bent edge 10 electrical connecting elements 12 are provided, which are constructed, for example, in the way of plug contacts and can be connected to the high-tension source via high-tension testing equipment known per se and not illustrated here, for the purpose of carrying out a leakage test.

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The invention is not limited to the embodiment illustrated, but extends to executions wherein, for example, instead of the electrically conductive bottom layer made of the plastic material specified other type of electrically conductive layers, for example, a fine-meshed metal screen, continuous or perforated metal foils, are used. Depending on the application, a further flexible layer made of plastic material or rubber may be provided underneath the electrically conductive layer to improve, for example, the mechanical strength, heat insulation or other desirable properties.

Claims

1. A container floor for large-volume containers erected on natural ground to accommodate liquids, suspension or the like, wherein said floor is a flexible corrosion- and abrasion-resistant foil, whose edge is joined on all sides pressure-tight to the side walls of the container, which may be lined, and wherein the foil is adapted to sit directly on the ground and includes at least an upper abrasion- and corrosion-resistant carrier layer and a lower electrically-conductive layer.

2. A container floor according to claim 1, wherein the electrically conductive S.layer is embedded into the carrier layer. 15 3. A container floor according to claim 1, wherein the electrically conductive lower layer is constructed as a thin plastic foil and is firmly joined with the underside of the upper carrier layer.

4. A container floor according to any one of the claims 1 to 3, wherein the foil forming a so-called geo-diaphragm includes sulpho-chlorinated polyethylene on polymer base (CSM). A container floor according to any one of the claims 1 to 3, wherein the foil includes strips of elastomer webs which are firmly joined with each other, the longitudinal edges of which are tapered, and wherein the electrically conductive lower layer is narrower than the upper carrier layer.

6. A container floor according to claim 5, wherein the elastomer webs with their tapered edges are bonded in such a manner that an overlapping of the electrically conductive layer is produced.

7. A container floor for large-volume containers substantially as herein described with reference to the accompanying drawings.

8. A large-volume container having a container floor as claimed in any one of the preceding claims. DATED: 22 September, 1998 PHILLIPS ORMONDE FITZPATRICK Attorneys for: STAHLGRUBER OTTO GRUBER GmbH CO. e a s e I ,I_ ABSTRACT A container floor for large-volume containers erected on natural ground to accommodate liquids, suspension or the like, characterised by a flexible corrosion- and abrasion-resistant foil, whose edge is joined on all sides pressure-tight to the side walls of the container which could be lined, wherein the foil consists at least of one top abrasion- and corrosion-resistant carrier layer and one bottom electrically- conductive layer. a a So C WINWOR'DGAYNODELETE 520984 DOC el I