AU2018241046B1 - Catchment container for and method of containing escaped contents - Google Patents

Abstract

A relocatable reusable secondary containment device for supporting a tank container charged with a hazardous substance provides emergency containment for escaping tank contents in event of tank rupture or leakage, the device comprising a receptacle locatable beneath the tank container and having docking means on an upright wall that is adapted to support the container in releasable engagement.

Description

CATCHMENT CONTAINER FOR AND METHOD OF CONTAINING ESCAPED CONTENTS

Field of invention [01] This invention relates to a secondary containment device for supporting a tank container, containing a hazardous substance while providing emergency containment for escaping tank contents in event of tank rupture or leakage.

Background to the invention [02] A tank container that is built to standards set out by the International Standards Organisation (ISO) is commonly referred to as an “ISO tank”, or even “Isotank”. Building to this standard makes the tank unit suitable for transportation, as it is confined within a supporting structure adapted for securement to a transportation platform. Although the frame is made to fit standard transportation platforms, for example a 40ft (12m) container, or a 20ft (6m) container, the tank vessel itself need not be of a standard ISO size.

[03] A significant operating cost borne by liquid handling operations relates to providing catchment for potential spills. Incidents involving chemicals often result in explosions or fires, causing death and serious injury as well as damage to property and the surrounding environment. Secondary containment devices, often loosely referred to as bunds, are well known, typically functioning to protect the environment by providing a secondary containment system for liquids which may spill, or otherwise leak, from a storage container and which may cause pollution or pose an environmental hazard.

[04] Legislative requirements may dictate the size of secondary containment required for a specified operation. These tend to differ from one jurisdiction to another. While a true bund would be large enough to contain the entire content of the primary containment device, such as an ISO tank, a secondary containment device would have a smaller capacity, sufficient only for relatively minor spills up to about 3000 litres.

2018241046 02 Oct 2018 [05] A common form of bund structure is a continuous concrete wall defining a sealed enclosure into which a primary container is placed. The enclosure is of sufficient sealed volume to contain the entire contents of the primary container, should it leak or rupture catastrophically. This form of secondary containment device is not readily (if at all) transportable. Generally, it is not intended for relocation once built.

[06] Secondary containment devices having plastic and steel walls are also well known. The wall and other component materials used are selected according to the chemical properties of the liquid to be held in the primary container and the hydrostatic pressure that the contents may exert on the wall. In remoter areas, rudimentary containment structures may be found that comprise earth walls or sandbagged barriers. Sometimes these are fitted with a lining of plastic or other membrane. Such linings often deteriorate rapidly or are torn or penetrated.

[07] A secondary containment system for use in remote areas and transportable to be relocatable is disclosed in Australian patent application publication AU 2011236073. It provides a modified form of shipping container adapted to provide secondary containment for a tank placed therein. The result is a portable system suitable for use in remote areas. A drawback experienced with this arrangement is that the primary containment tank is contained within the catchment volume of the modified container, resulting in the tank becoming externally wetted and even partially submerged in serious cases of leakage, even though this results in a portion of the stored liquid remaining in that part of the tank which lies below the rim of the secondary containment wall.

[08] The website <suigeneris.co.uk> discloses a moulded spill containment tub having a composite wall with depressions at inward corners of the rim, into which the corners of a pallet-mounted intermediate bulk container (IBC) can be located to rest. No form of secure attachment of the IBC pallet to the tub is contemplated to ameliorate risk of the IBC being displaced from catchment position if bumped. The flexible nature of the tub wall creates risk of buckling under side impact, resulting in spillage.

2018241046 02 Oct 2018 [09] US patent 5323903 teaches use of separately supplied tie-downs as means for securing equipment items together.

[010] There thus remains a need for a secondary containment device that is transportable and relocatable and that is in a standardised form, adapted for supporting various kinds of primary vessels above a containment volume with substantially rigid sides and containing different types of substances.

Objects of the invention [011] It is an object of this invention to address the shortcomings of the prior art and, in doing so, to provide a secondary containment device that alleviates the stated drawbacks.

[012] The preceding discussion of the background to the invention is intended to facilitate an understanding of the present invention. However, it should be appreciated that the discussion is not an acknowledgement or admission that any of the material referred to was part of the common general knowledge in Australia or elsewhere as at the priority date of the present application.

[013] Further, and unless the context clearly requires otherwise, throughout the description and the claims, the words ‘comprise’, ‘comprising’, and the like are to be construed in an inclusive sense - that is in the sense of “including, but not being limited to” - as opposed to an exclusive or exhaustive sense - meaning “including this and nothing else”.

Summary of invention [014] According to a first aspect of the invention, there is provided a relocatable catchment receptacle for containing escaped contents of a primary containment vessel in the event of a leakage, the receptacle comprising:

a. a road-transportable base having an upstanding wall sealingly connected thereto to define, laterally enclosed above the base, an uncovered catchment volume for escaped contents of a primary containment vessel, and

2018241046 02 Oct 2018

b. docking means associated with the wall, adapted to supportively receive, for secure attachment to the wall, in operative catchment position above the volume within an imaginary upward extension of the wall and spaced from the base at a level substantially above an upper rim of the wall, said primary containment vessel contained within a tank container; and

c. an engageable locking member and being operable to secure the tank container to the wall in said operative catchment position.

[015] In a preferred form of the invention, the receptacle has a volume larger than the volume of the vessel. Preferably, the volume has a footprint exceeding that of the primary containment vessel.

[016] In an embodiment of the invention, the volume has a footprint at least substantially equal to that of a container tank unit housing the primary containment vessel.

[017] In a still further preferred form of the invention, the docking means comprises a formation projecting upwardly from the wall for engagement with a mating formation of the tank container.

[018] The locking member may comprise a movable part displaceable to lock together the respective formations.

[019] According to a second aspect of the invention there is provided a method of providing containment for an escaped substance, the method comprising:

a. providing an open catchment container defining a volume laterally bounded by a wall having a rim of substantially constant elevation and sealingly secured to a base;

b. providing a dockable tank container comprising a primary containment vessel containing unescaped substance,

c. locating the tank container above the catchment container at an elevation above the rim, and

2018241046 02 Oct 2018

d. docking the tank container to a structural element of the catchment container so that the catchment container is operatively located to receive a substance escaping from the primary vessel, and

e. providing and operating a releasable locking member whereby to securely lock the tank container in operative catchment location above the catchment volume.

[020] In a preferred form of the invention, the primary vessel, when docked, occupies a volume laterally bounded by an upward extension of the wall.

[021] .In a further preferred form of the invention, the structural element of the catchment container comprises a formation projecting upwardly from the wall for releasable engagement with a mating formation of the tank container when docking.

[022] In a preferred embodiment, the releasable locking member comprises a movable part displaceable to lock together the respective formations when docked.

[023] A relocatable system for liquid storage comprising:

a. a tank container housing a primary containment vessel chargeable with a liquid;

b. a catchment receptacle for containing escaping contents of the primary containment vessel in the event of a leakage; and

c. support means comprising a wall of the receptacle adapted for supporting the tank container in effective catchment location above the receptacle wall within an area not exceeding a footprint of the receptacle; and

d. releasable locking means operable for locking the tank container to the support means.

[024] Preferably, the locking means comprises a first formation projecting upwardly from the wall and the tank container comprises a second formation configured for downward mating engagement with the first formation.

2018241046 02 Oct 2018 [025] In an embodiment, the locking means comprises a moveable member displaceable to secure the first and second formations releasably together

Brief description of drawing [026] In order that the invention may be readily understood, and put into practical effect, reference will now be made to the accompanying figure in which a preferred embodiment of the invention is illustrated. Thus:

Figure 1 shows in schematic form a diagram of a preferred embodiment of the system of this invention wherein an ISO tank is shown ready for positioning on a supporting receptacle of the invention.

Detailed description of an embodiment of the invention [027] Preferred features of the present invention will now be described with reference to the drawings, the features of which are not to be understood or construed as limiting on the scope of the invention.

[028] Referring to Figure 1, in a preferred embodiment of this invention, a spillage containment system is generally denoted by the number 10 and shown in preparation for use with a primary storage tank 20, such as an ISO tank. It should be understood that such use is not to be considered restrictive.

[029] The containment system is constructed from steel selected for inertness to a wide range of chemicals. An example is grade 304L stainless steel.

[030] The containment system is comprised of a spillage-receiving receptacle 12 defined by a wall 14 which is sealingly connected to a base 16. The wall is of corrugated steel sheeting, of the kind known in the construction of shipping containers and is supported by way of a frame 18 having corner posts 24 and transverse rib elements extending between them. There are upper ribs 26 running adjacent the upper rim 30 of wall 14 and lower ribs 18 adjoining base 16. The wall structure provides rigidity under horizontal vector impact and resistance to buckling from vertical loading.

[031] Directional arrows D indicate that a tank unit 20 is lowered onto and lifted from the catchment receptacle from time to time for use and replacement

2018241046 02 Oct 2018 respectively. In use, the tank unit rests on the receptacle structure rather than within it. This enables it to be monitored visually from afar for leaks, without reliance on instrumentation that may be vulnerable to deterioration and failure in remote areas and harsh climatic conditions. A person inspecting for leaks would not be required to look into the volume, but would in many cases be able to see a liquid dripping from the primary containment vessel or running down the side surfaces to a low point for dripping away.

[032] The tank unit comprises a tank container. In this embodiment, the tank container has a rigid support frame 34, within which it is securely held for relocation and transportation a generally tubular, cigar-shaped tank vessel. Support frame 34 has corner posts 36 with foot portions 38 having a cavity for fitting over mating formations found on the receptacle frame, or on other shipping containers or transportation platforms.

[033] In the present invention, receptacle frame 18 is adapted in shape and size to have integrated formations in its structure for receiving the corner posts 36 of the tank unit frame 34 in supporting engagement. To this end, twist-lock formations 40 are connected to the corner posts, to project upwardly from receptacle frame 18 at positions configured to coincide with corner feet 38 of tank unit 20. Greater detail is seen in callout (b), where it can be seen that projection 40 is generally shaped in the form of a truncated pyramid, which has a base section 42 that is secured to posts 24. An upper section 44 of the pyramid has a passage 46 extending horizontally through it for receiving a locking device (not shown) that secures the respective mating frames portions together. Passage 46 aligns with an aperture (not shown) in tank unit frame foot 38. Locking is by means conventional in the logistics field for securing shipping containers.

[034] When the container tank unit 20 holding primary vessel 22 is operatively mounted above volume 12, were wall 14 to be extended upwards, vessel 22 would be in surrounded by it. Volume 12 therefore has a footprint that exceeds that of vessel 22, but not of container tank frame 34 and unit 20. The volume footprint is substantially equal to the footprint of the tank container unit 20.

2018241046 02 Oct 2018 [035] To render the receptacle volume substantially leak proof, joins 32 between wall section 14 and base 16 are sealed with a caulking agent selected to resist deterioration when in contact with the substance contained in the primary container. An example of caulking agent suitable for exposure to oil or lighter fuels is the Masterbond EP30P two-component epoxy system. The supplier is Master Bond, Inc. of 154 Hobart Street, Hackensack NJ, USA. For resistance to exposure to an acid such as sulphuric acid, an epoxy system is considered suitable, an example being the EP21ARHT formulation available under the brand name Masterbond from Master Bond, Inc. Other examples will be known to those skilled in the art.

[036] In an alternative embodiment, the catchment volume base 16 and wall 14 are lined. This can be as a replacement for caulking or sealing, but is preferably provided as an additional, but primary catchment membrane for containment. The liner is preferably a continuous membrane, but may be made of sealingly joined sections. The liner material will depend on the application, but examples of versatile membrane materials include rubber, butyl rubber, neoprene and the like. These may be treated for enhancing their resistance to deterioration from exposure to ultra-violet radiation.

[037] To ensure the base liner fabric is preserved from external damage and spill capability maintained, the frame is fabricated from steel for enhancing longevity under a wide range of environmental conditions. The steel may be mild steel.

[038] The base 16 may be orientated and attached within the wall 14 to slope towards a corner at which a drain cock is installed to allow for recovery of spilled substances, or for their safe disposal.

[039] Preferably, the volume of the catchment receptacle is sufficient to receive at least a portion of the contents of the ISO tank supported above it. Further preferably, it should be large enough to contain the entire contents, should they leak out. This would be of greater importance in remote areas, where assistance is not readily available and when the condition of the tank being supported is not checked a regular, short intervals. It is also of great importance if

2018241046 02 Oct 2018 the tank contents are of a highly hazardous nature, where water courses or ground water would be contaminated, or where extremely harmful vapours would be released.

[040] The ISO tank and secondary containment receptacle of the invention may be transported separately to the site of intended use where they will be assembled and the ISO tank mounted on the receptacle frame for use. Filling of the receptacle may be performed on site. Alternatively, the ISO tank may be filled off site and transported to the site, where it will be lifted on to the receptacle frame by means of a crane or other suitable lifting apparatus. Further alternatively, the tank unit may be mounted off-site, filled or unfilled and then transported to the site of deployment. The system of the invention therefore is versatile to provide the user with a number of options for its optimal employment. The containment unit is preferably certified under the International Convention for Safe Containers (referred to as being “CSC plated”) for road, rail and sea transportation.

[041] It will be appreciated that instead of the receptacle being of generally rectangular proportions, other forms may be employed, for example an oval, provided transportability and buckling-resistance are not unacceptably compromised. The stackable weight of the unit discussed in the preferred embodiment is in excess of 30 tonnes.

[042] These embodiments merely illustrate particular examples of the method, kit and apparatus of the invention providing means for the monitoring of effort expended in performing exercise involving gripping. With the insight gained from this disclosure, the person skilled in the art is well placed to discern further embodiments by means of which to put the claimed invention into practice.

Claims (9)

1. A relocatable catchment receptacle for containing escaped contents of a primary containment vessel in the event of a leakage, the receptacle comprising:

a. a road-transportable base having an upstanding wall sealingly connected thereto to define, laterally enclosed above the base, an uncovered catchment volume for escaped contents of a primary containment vessel, and

b. docking means associated with the wall, adapted to supportively receive, for secure attachment to the wall, in operative catchment position above the volume, within an imaginary upward extension of the wall and spaced from the base at a level substantially above an upper rim of the wall, said primary containment vessel contained within a tank container; and

c. an engageable locking member and being operable to secure the tank container to the wall in said operative catchment position, wherein the docking means comprises a formation projecting upwardly from the wall for engagement with a mating formation of the tank container.

2. A receptacle according to claim 1 wherein the volume has a footprint exceeding that of the primary containment vessel.

3. A receptacle according to claim 1 wherein the volume has a footprint substantially equal to that of a container tank unit housing the primary containment vessel.

4. A receptacle according to any one of the preceding claims, wherein the locking member comprises a movable part displaceable to lock together the respective formations.

2018241046 28 Dec 2018

5. A method of providing containment for an escaped substance comprising:

a. providing an open catchment container defining a volume laterally bounded by a wall having a rim of substantially constant elevation and sealingly secured to a base;

b. providing a dockable tank container comprising a primary containment vessel containing unescaped substance,

c. locating the tank container above the catchment container at an elevation above the rim;

d. docking the tank container to a structural element of the catchment container so that the catchment container is operatively located to receive a substance escaping from the primary vessel; and

e. providing and operating a releasable locking member whereby to securely lock the tank container in operative catchment location above the catchment volume, wherein the structural element of the catchment container comprises a formation projecting upwardly from the wall for releasable engagement with a mating formation of the tank container when docking.

6. A method according to claim 5 wherein the primary vessel, when docked, occupies a volume laterally bounded by an upward extension of the wall.

7. A method according to claim 5 or claim 6, wherein the releasable locking member comprises a movable part displaceable to lock together the respective formations when docked.

8. A relocatable system for liquid storage comprising:

a. a tank container housing a primary containment vessel chargeable with a liquid;

2018241046 28 Dec 2018

b. a catchment receptacle for containing escaping contents of the primary containment vessel in the event of a leakage; and

c. support means comprising a wall of the receptacle adapted for supporting the tank container in effective catchment location above the receptacle wall within an area not exceeding a footprint of the receptacle; and

d. releasable locking means operable for locking the tank container to the support means, the locking means comprising a first formation projecting upwardly from the wall, wherein the tank container comprises a second formation configured for downward mating engagement with the first formation.

9. The storage system of claim 8 wherein the locking means comprises a moveable member displaceable to secure the first and second formations releasably together.