WO2014131082A1

WO2014131082A1 - A fluid holding tank and method of assembly thereof

Info

Publication number: WO2014131082A1
Application number: PCT/AU2014/000181
Authority: WO
Inventors: Reginald Lindsay CULLEN
Original assignee: Restore Environmental Ρtυ Ltd
Priority date: 2013-02-27
Filing date: 2014-02-27
Publication date: 2014-09-04
Also published as: AU2014223303B2; AU2014223303A1

Abstract

A tank for fluids has an inner tank lining for contact with a fluid to be stored and an outer boundary wall assembly including a plurality of interconnected members. Panels are disposed between the wall assembly and the lining with the panels being free to move relative to each other. The boundary wall assembly is arranged to increase in perimeter length in response to fluid pressure increasing within the tank in order to cope with the increased pressure.

Description

A FLUID HOLDING TANK AND METHOD OF ASSEMBLY

THEREOF

TECHNICAL FIELD

[01] The present invention relates to tanks for storing fluids. More particularly, the present invention provides a tank that is suited for use as a holding tank for retaining liquids that are produced during mining and coal seam gas generation, for example.

BACKGROUND

[02] The discussion of any prior art documents, techniques, methods or apparatus is not to be taken to constitute any admission or evidence that such prior art forms, or ever formed, part of the common general knowledge.

[03] There is a need in a number of industries for the provision of large capacity holdings tanks. One area where this need arises is in the extraction of coal seam gas. During coal seam gas extraction a steel encased bore is drilled into the coal seam some 100 to 1500 meters below ground. Both gas and water come to the surface through the bore. The produced water is either reinjected into isolated formations, released into streams, used for irrigation or sent to large holding tanks which act as evaporation ponds.

[04] There have been a number of approaches in the prior art to forming holding tanks on site. For example, in international patent publication number O2012/142661 (published 26 October 2012) there is described a storage tank comprising a plurality of pre-stressed reinforced concrete panels which define a circular storage region and which are retained between a series of posts. A liner is disposed inside the storage region and against the panels for retaining liquids to be stored. The posts are formed with opposed vertical side edges between which ends of the concrete panels are received. [05] A cable is provided that traverses the perimeter of the wall of the tank and which reinforces the tank wall. It is suggested that the cable be able to withstand tensions of 250kN. It will be understood therefore that the tank described in this document includes rigid panels which are held fast radially with the vertical posts by virtue of the panel ends being received between opposed edges protruding from the posts.

[06] It is an object of the present invention to provide a tank which may be readily assembled and which is an improvement over, or at least a useful alternative to, those tanks that have hitherto been known in the prior art.

SUMMARY OF THE INVENTION

[07] According to a first aspect of the present invention there is provided a tank for fluids comprising:

an inner tank lining for contact with a fluid to be stored;

an outer boundary wall assembly including a plurality of interconnected members; and

panels disposed between said wall assembly and said lining, said panels being free to move relative to each other;

wherein the outer boundary wall assembly is arranged to increase in perimeter length in response to fluid pressure increasing within the tank.

[08] In a preferred embodiment of the invention the interconnected members of the outer boundary wall comprise a plurality posts with transverse members disposed between the posts.

[09] However, other embodiments of the invention are possible wherein the interconnected members of the outer boundary wall do not include a plurality of posts but, for example, a plurality of interconnected diagonal members and rails. [10] The panels may be maintained in an upright position simply by abutment with the outer boundary wall.

[11] Alternatively, in other embodiments the panels may be loosely fastened to the outer boundary wall. For example, the panels may be loosely fastened to the rails or the posts.

[12] Preferably the panels are composite panels of a type having a foam core sandwiched by opposed metal sheets.

[13] Alternatively, and without limitation, the panels may be comprised of any one of: structural ply; reinforced concrete; fibercrete concrete skins over a polystyrene core.

[14] In a preferred embodiment of the invention end portions of adjacent panels overlap in order to accommodate an increase in the circumference of the tank as it fills in use.

[15] The end portions of adjacent panels may be formed with complementary formations to accommodate said circumference increase.

[16] For example, the end portions of adjacent panels may be formed with overlapping tongue and groove formations.

[17] The posts may comprise square hollow section posts extending upwardly from support plates.

[18] The support plates may be welded to the bottom of the section posts or alternatively they may be connected to the bottom of the posts with shear plates that fit internally into the post.

[19] In the preferred embodiment of the invention the transverse members comprise rails formed from extruded hollow steel sections. [20] Preferably the hollow steel sections are connected to the posts with shear plates and pins, e.g. bolts may be used.

[21] In a preferred embodiment of the invention the transverse members comprise a number of rows of the hollow steel sections grouped together.

[22] Preferably the transverse members further comprise a plurality of top rails disposed between the upper ends of adjacent posts.

[23] , The top rails are preferably connected to the adjacent posts with a gusset plate and pins, e.g. bolts.

[24] According to a further aspect of the present invention, there is provided a method for retaining a fluid including:

installing a plurality of posts upon a level predetermined perimeter; connecting transverse members between adjacent posts to thereby form an outer boundary wall around the level perimeter;

placing a plurality of panels around the inside of the outer boundary wall; and

installing a fluid retaining liner inside the plurality of panels. BRIEF DESCRIPTION OF THE DRAWINGS

[25] The Detailed Description is not to be regarded as limiting the scope of the preceding Summary of the Invention in any way. The Detailed Description will make reference to a number of drawings as follows:

[26] Figure 1 depicts a fluid storage tank according to a preferred embodiment of the present invention in use,

[27] Figure 2 is a detailed view of a portion of a boundary wall of the storage tank of Figure 1. [28] Figure 3 is a detail of the connection between a rail of the boundary wall and an upright post of the boundary wall with connection pin (visible in Figure 6) omitted for clarity.

[29] Figure 4 is a detailed view of the connection between a top rail of the boundary wall and the upright post.

[30] Figure 4 A shows a post used to interconnect transverse members in the preferred embodiment of the invention.

[31] Figure 4B is a front view of the post of Figure 4A.

[32] Figure 4C is a top plan view of the post of Figure 4A.

[33] Figure 4D is a first sectional view through the post of Figure 4A.

[34] Figure 4E is a second sectional view through the post of Figure 4A.

[35] Figure 5 is a cross section of a portion of a composite panel used in a preferred embodiment of the present invention.

[36] Figure 6 is a view of a pin used in the interconnection of rails to posts in the boundary wall of the tank of Figure 1.

[37] Figure 7 depicts a side view of a portion of a boundary wall of a storage tank according to a further embodiment of the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[38] Referring now to Figure 1 , there is provided a tank 2 for storing a fluid 14, which is typically water but could also be another liquid or fluid. Where a lighter than air fluid is to be stored then a lid will need to be provided over the top of the tank. [39] The tank 14 comprises an inner tank lining 28 (best seen in Figure 4) for contact with a fluid to be stored. If leak detection is required then a second lining 30 is also provided adjacent the inner tank lining 28 with a detection device arranged to detect pressure indicating fluid leaking between the two linings. Such an arrangement for leak detection is known in the prior art and so will not be described in further detail here.

[40] Referring again to Figure 1 , the tank 2 also includes an outer boundary wall assembly 11 including a plurality of interconnected members comprising posts 4, and transverse members 8 and 10. Panels 12 are disposed between the wall assembly 1 and the lining 28. The panels 12 are not rigidly fastened to the outer boundary wall and are free to move relative to each other.

[41] Other arrangements for implementing the boundary wall are possible. For example, Figure 7 shows a portion Of a boundary wall 40, which is formed from a plurality of interconnected diagonal members and rails.

[42] Referring again to Figure 1 , once the tank 2 is filled with storage fluid, pressure is exerted outwardly against the panels so that the panels are maintained in an upright position simply by abutment with the outer boundary wall. Nevertheless, during assembly the panels may be loosely fastened or clamped to the rails or the posts to resist wind load.

[43] End portions of adjacent panels may be arranged to overlap in order to accommodate an increase in the circumference of the tank as it fills in use without gaps forming between adjacent panels. For example, the end portions of adjacent panels may be formed with complementary overlapping formations to accommodate said circumferential increase.

[44] Referring now to Figure 4, in the presently described preferred embodiment of the invention the end portions of adjacent panels 12a and 12b are formed with overlapping tongue 26 and groove 24 formations. [45] Consequently, as the hydrostatic pressure exerted by the stored water increases during filling of the tank the panels press outwardly on posts 4. In response the posts 4 move slightly outward radially so that the circumferential length of the boundary wall formed by the posts and the transverse members 10 and 8 increases. That movement is accommodated by the adjacent panels moving slightly apart. Due to the overlapping of the adjacent panels (by means of the tongue and groove formations 26, 24) the continuity of the surface presented by the panels to the inner lining 28 is maintained without substantial gaps forming between the adjacent panels.

[46] Preferably the panels are composite panels as illustrated by the panel cross section 38 shown in Figure 5. Such a panel has a non-rigid filler or core 34 sandwiched by opposed rigid sheets 36 which may for example be steel sheets. Alternatively, and without limitation, the panels may be comprised of any one of: structural ply; reinforced concrete; fibrecrete concrete skins over a polystyrene core.

[47] It will be realized that by using a composite panel, as opposed to a pre- stressed concrete panel as is common in the prior art, the cost of production of the tanks is reduced. Furthermore, the cost of transporting the panels to site for assembly of the tanks is also greatly reduced as the weight of a composite panel is much less than the weight of an equivalent pre-stressed concrete panel. Additionally, once the panels are transported to site the assembly process for making the tank is far easier since the panels are light and easily handled relative to concrete panels, which are far heavier.

[48] As has been explained, in the preferred embodiment of the invention the interconnected members of the outer boundary wall comprise a plurality of posts with transverse members disposed therebetween. However, other embodiments of the invention are possible wherein the interconnected members of the outer boundary wall do not include a plurality of posts but, for example, a plurality of interconnected diagonal members and rails as illustrated in Figure 7. [49] Referring now to Figures 2, 4 and 4A, the posts 4 comprise square hollow section posts extending upwardly from support plates. Of course, in other embodiments of the invention posts of other cross sections, for example poles having a circular cross section, might be used instead of square section posts 4.

[50] The support plates 6 may be welded to the bottom of the posts 4 or, more preferably connected to the bottom of the posts with shear plates that fit internally into the posts. As best seen in Figure 4A, the posts include pairs of lateral connection tongues 16 between which the ends of the transverse members 8 are received.

[51] Each of the three rows of transverse members 8 comprise rails formed from extruded hollow steel sections. As shown in detail in Figure 3, the hollow steel sections 8 are connected to the posts with shear plates 8 and pins (illustrated in Figure 6) which traverse corresponding holes 20 formed through the end of the rails 8, connection tongues 16 and shear plates 18. Pins are preferred since they may be simply dropped into place though. The pins could be provided in the form of bolts. Once the tank is filled with liquid the hydrostatic pressure on the transverse members, i.e. rails 8 causes the pins to be retained tightly in place. Once the tank is empty the pins can be quickly removed since they include removal rings 33 (Figure 6). Accordingly, using the pins aids in the speedy assembly and disassembly of the tank.

[52] Referring again to Figures 4 and 4A, the top rails 10 of the boundary wall are connected between adjacent posts 4 with a gusset plate 22 and friction bolts that penetrate through holes 23 formed in the ends of the rails and the gusset plates 22. It will be noted that the outer hole formed in gusset plate 22 is provided in the form of a slot to allow for some freedom of movement of the top rails 10 relative to the post as the tank is filled. [53] In general terms a tank according to the present invention may be assembled as follows:

the posts 4 are located upon a level predetermined perimeter;

the transverse members 8 and 10 are connected between adjacent posts with pins 32 to thereby form the outer boundary wall 1 1 around the level perimeter; ·

the panels 12 are then installed around the inside of the outer boundary wall; and

a fluid retaining liner 28 is then placed inside the panels 12.

[54] A specific preferred assembly procedure for a particular tank according to a preferred embodiment of the invention is as set out in the following points which is in respect of a particular exemplary embodiment of the present invention:

[55] Site for the reservoir is stripped. Cut and fill if necessary to form a flat perimeter to the circumference of the tank with a grade of 1 :75 fall to the centre of the reservoir for leak detection outlet if required.

[56] The system is basically like building a fence with post and rails.

[57] The square hollow section posts 4, which in this example are 150mm x 150mm x 6mm thick, with support plates 6, are placed around the perimeter of the tank with the use of a laser level. The support plate 6 may be welded to this post or connected with shear plates that fit internally in the square hollow post.

[58] The posts are connected by three (3) transverse members in the form of horizontal rails 8 that are rectangular hollow sections 150mm x 100mm x 4mm thick, with 50mm diameter pins and shear plates.

[59] The top rail 10 is then installed. The top rail 10 is a 150mm parallel flange hot rolled section and is connected to the post with a gusset plate (item 22 of Figure 4) and 24mm diameter bolts. [60] The composite wall panels 12 are placed in position and may be clamped to the rail system to resist wind load. This is not a positive connection to allow for movement.

[61] A single liner (item 28 of Figure 4) or double liner (item 28 and item 30 of Figure 4) is installed depending on the type of fluid to be stored.

[62] A leak detector may be installed, which is a PVC tube with a float mechanism visually arranged to visually indicate that a leak has occurred in the principal liner. In remote areas the float has a limit switch that can be connected to a safety panel at administration. Power to the safety panel can be provided with solar panels and battery back- up.

[63] In use, as the reservoir fills the wall panels transfer the horizontal pressure to the rails. This horizontal pressure is converted into tension and bending in the rail system.

[64] As the storage tank 2 is filled with fluid such as water, the boundary wall 11 is placed under hoop tension. As this tension is applied to the horizontal rail system the reservoir is increased in size with movement of the square hollow section posts 4 moving radially outwards. The membrane material 28 is flexible and easily stretches to accommodate this slight increase in size. Furthermore, the panels 12 are also able to move slightly apart by virtue of the overlapping tongue and groove formations 26, 24. Consequently the tank is able to cope with the increasing water pressure without failure and without the need for a high tension member Such as the perimeter cable of the prior art tank previously discussed herein.

[65] In compliance with the statute, the invention has been described in language more or less specific to structural or methodical features. The term "comprises" and its variations, such as "comprising" and "comprised of is used throughout in an inclusive sense and not to the exclusion of any additional features. [66] Throughout the description and claims of this specification, the singular encompasses the plural unless the context otherwise requires. In particular, where the indefinite article is used, the specification is to be understood as contemplating plurality as well as singularity, unless the context requires otherwise.

[67] Features, integers, characteristics, compounds, chemical moieties or groups described in conjunction with a particular aspect, embodiment or example of the invention are to be understood to be applicable to any other aspect, embodiment or example described herein unless incompatible therewith.

[68] It is to be understood that the invention is not limited to specific features shown or described since the means herein described comprises preferred forms of putting the invention into effect. The invention is, therefore, claimed in any of its forms or modifications within the proper scope of the appended claims appropriately interpreted by those skilled in the art.

Claims

CLAIMS:

1. A tank for fluids comprising:

an inner tank lining for contact with a fluid to be stored;

panels disposed between Said wall assembly and aid lining, said panels being free to move relative to each other;

2. A tank according to claim 1 , wherein the interconnected members of the outer boundary wall comprise a plurality posts with transverse members disposed between the posts.

3. A tank according to claim 1 or claim 2, wherein the panels are maintained in an upright position by abutment with the outer boundary wall.

4. A tank according to any one of the preceding claims, wherein the panels are loosely fastened to the outer boundary wall.

5. A tank according to claim 2, wherein the panels are loosely fastened to the rails or the posts.

6. A tank according to any one of the preceding Claims, wherein the panels are composite panels.

7. A tank according to claim 6, wherein the composite panels have a foam core sandwiched by opposed metal sheets.

8. A tank according to any one of claims 1 to 4, wherein the panels are comprised of any one of: structural ply; reinforced concrete; fibercrete concrete skins over a polystyrene core.

9. A tank according to any one of claims 1 to 8, wherein the end portions of adjacent panels overlap to accommodate an increase in the circumference of the tank as it fills in use.

10. A tank according claim 9, wherein the end portions of adjacent panels are formed with complementary formations to accommodate said circumference increase.

1 1. A tank according to claim 10, wherein the end portions of adjacent panels are formed with overlapping tongue and groove formations.

12. A tank according to claim 2 or claim 4 wherein the posts comprise square hollow sections extending upwardly from support plates.

13. A tank according to claim 12, wherein the support plates are welded to the bottom of the section posts.

14. A tank according to any one of claims 10 to 13, wherein the transverse members comprise rails formed from extruded hollow steel sections:

15. A tank according to any one of claims 10 to 13, wherein the hollow steel sections are connected to the posts with shear plates and pins.

16. A tank according to any one of claims 10 to 15, wherein the transverse members comprise a number of rows of the hollow steel sections grouped together.

17. A tank according to claim 16, wherein the transverse members further comprise a plurality of top rails disposed between the upper ends of adjacent posts.

18. A tank according to claim 17, wherein the top rails are connected to the adjacent posts with a gusset plate and pins.

19. A method for retaining a fluid including:

placing a plurality of panels around the inside of the outer boundary wall; and

installing a fluid retaining liner inside the plurality of panels.

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