Floating liquid intake

Abstract

A floating liquid intake for a liquid suction removal system, the liquid intake comprising housing defining an internal cavity. The housing has a hollow and buoyant annular body, an upper cover and a lower cover. The internal cavity is formed between the upper and lower covers. A substantially annular inlet is formed in the annular body for ingress of liquid into the cavity. The annular body has a buoyancy sufficient for the liquid intake to float in a liquid with the annular inlet submerged below the surface of the liquid in which the liquid intake is floating. A pipe extends into the cavity and the pipe includes an inlet that in use is open below the surface of the liquid within the cavity. The pipe extends outside of the cavity for connection to a liquid suction removal system.

Claims

1. A floating liquid intake for a liquid suction removal system, the liquid intake comprising a housing defining an internal cavity, the housing having: a buoyant annular body, an upper cover extending upwardly from the annular body, and a lower cover extending downwardly from the annular body, the internal cavity being formed between the upper and lower covers, a substantially annular inlet formed in the annular body for ingress of liquid into the cavity, a pipe extending into the cavity, the pipe including an inlet that in use is open below the surface of the liquid within the cavity, the pipe extending outside of the cavity for connection to a liquid suction removal system, wherein the annular body has a buoyancy sufficient for the liquid intake to float in a liquid with the annular inlet submerged below the surface of the liquid in which the liquid intake is floating, so that liquid entry into the cavity is by suction through the annular inlet from below the surface of the liquid.

2. A floating liquid intake according to claim 1, the annular body being a rotational moulded body.

3. A floating liquid intake according to claim 1, the annular body being a hollow body that is optionally filled with a buoyant material.

4. A floating liquid intake according to claim 3, the buoyant material being polyurethane (PU) foam.

5. A floating liquid intake according to claim 1, the annular body having upper and lower surfaces and radially spaced inner and outer edges.

6. A floating liquid intake according to claim 5, the upper cover being attached to the upper surface and the lower cover being attached to the lower surface.

7. A floating liquid intake according to claim 5, the annular body having an opening through which the pipe extends and the opening extending through the annular body from the outer edge to the inner edge.

8. A floating liquid intake according to claim 1, the annular body having an opening through which the pipe extends.

9. A floating liquid intake according to claim 1, the liquid intake being generally airtight when submerged to a level at which the annular inlet is below the surface of the liquid in which the liquid intake is floating.

10. A floating liquid intake according to claim 1, including debris screens overlying the annular inlet.

11. A floating liquid intake according to claim 1, the upper cover including a central closure for access to within the housing when removed.

12. A floating liquid intake according to claim 1, further including a submersible pump within the cavity.

13. A floating liquid intake according to claim 1, the lower cover including radial baffles projecting upwardly into the cavity.

14. A method of using a floating liquid intake according to claim 1, the method comprising connecting a liquid suction removal system to the pipe of the liquid intake and drawing water into the cavity of the liquid intake to generate a vacuum within the cavity, the vacuum tending to raise the level of liquid within the cavity relative to the level of the surface of the liquid in which the liquid intake is floating.

15. A method of using a floating liquid intake according to claim 14, wherein the level of water drawn into the cavity is such as to substantially fill the cavity with liquid.

16. A floating liquid intake according to claim 1, the intake being operable in water depths as shallow as 400 mm.

17. A floating liquid intake according to claim 1, the annular inlet being formed in the annular body adjacent to the lower cover.

18. A floating liquid intake according to claim 1, wherein the pipe has a diameter smaller than a diameter of the annular inlet.

19. A floating liquid intake for a liquid suction removal system, the liquid intake comprising housing defining an internal cavity, the housing having: a hollow and buoyant annular body, an upper cover extending upwardly from the annular body, and a lower cover extending downwardly from the annular body, the internal cavity being formed between the upper and lower covers, a substantially annular inlet formed in the annular body for ingress of liquid into the cavity, a submersible pump within the cavity and having an inlet which in use is submerged below the surface of the liquid in which the liquid intake is floating, the submersible pump having a discharge outlet in connection with a pipe that extends into the cavity, the pipe extending outside of the cavity for connection to a liquid suction removal system, wherein the annular body has a buoyancy sufficient for the liquid intake to float in a liquid with the annular inlet submerged below the surface of the liquid in which the liquid intake is floating, so that liquid entry into the cavity is by suction through the annular inlet from below the surface of the liquid.

20. A floating liquid intake according to claim 19, wherein the pipe has a diameter smaller than a diameter of the annular inlet.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) In order that the invention may be more fully understood, some embodiments will now be described with reference to the figures in which:

(2) FIG. 1 is a schematic illustration of a prior art pumping arrangement.

(3) FIG. 2 is a schematic illustration of a pumping arrangement according to the invention.

(4) FIG. 3 is a side view of a floating liquid intake according to one embodiment of the invention.

(5) FIG. 4 is a plan top view of a floating liquid intake according to the invention.

(6) FIG. 5 is an exploded perspective view of the floating liquid intake of FIG. 4.

(7) FIG. 6 is a cross-sectional view of the floating liquid intake of FIG. 4.

(8) FIG. 7 is a part cut-away perspective view of the floating liquid intake of FIG. 4.

(9) FIG. 8 is a side cross-sectional view through an annular body of the floating liquid intake of FIGS. 4 to 7.

(10) FIG. 9 is a perspective view of the annular body of FIG. 8.

(11) FIG. 10 is as illustration of the floating liquid intake of FIGS. 4 to 7 in use.

(12) FIG. 11 is a cross-sectional view of an alternative floating liquid intake according to the invention, incorporating a submersible pump.

(13) FIG. 12 is a part cut-away perspective view of the floating liquid intake of FIG. 11 with the submersible pump removed.

(14) FIG. 13 illustrates a comparison with an existing tailings dam and a tailings dam in which a liquid intake according to the present invention is employed.

DETAILED DESCRIPTION

(15) FIG. 2 is a similar illustration to FIG. 1, but showing schematically, a floating liquid intake 20 according to the present invention in use. FIG. 2 illustrates several of the same features as FIG. 1 and for those features, the same reference numerals are applied. In FIG. 2, it can be seen that the floating liquid intake 20 sits on the surface 21 of the body of water 13 rather than being suspended within the body of water 13 as shown in FIG. 1. It will therefore be appreciated, that the inlet to the liquid intake 20 is much higher than the inlet 16 of FIG. 1. This means that the inlet of the intake 20 of FIG. 2 is much further away from the silt and debris 12 and is located in water which should be cleaner than the water in which the inlet 16 of FIG. 1 is positioned.

(16) FIG. 3 is a side view of a liquid intake 30 according to the present invention. The liquid intake 30 can be the same as the liquid intake 20 of FIG. 2. The liquid intake 30 has a housing 31 comprising an annular hollow and buoyant body 32, an upper dome shaped cover 33, a lower dome shaped cover 34 and a pipe 35. The annular body 32 includes an annular inlet 36 which includes screens 37 to resist or prevent debris from passing through the inlet 36. The screens 37 are optional, although they are particularly useful for screening large debris, such as fish, leaves, sticks and the like.

(17) FIGS. 4 to 7 show different views of the intake 30 of FIG. 3 and reference will now be made to those figures. FIG. 4 is a plan view of the intake 30 and shows that the upper cover 33 includes a plurality of strengthening ribs 38 to extend radially from a central port closure 39. The closure 39 is provided for access to the interior of the intake 30 and may be removed and replaced as required. The closure 39 is optional and so alternative covers 33 will not include a closure 39. The closure 39 is intended principally for intakes that include a submersible pump as will be described later herein, as the ability to remove the closure 39 provides ready access to the submersible pump. In manufacture, the closure 39 can be formed integrally with the cover 33 and can be removed by cutting for example and re-attached by suitable fasteners. Alternatively it can be separately manufactured and suitable fasteners can be employed to make the connection between the closure 39 and the surrounding upper cover 33.

(18) A second port closure 40 is provided and likewise provides access to the cavity within the intake 30 and likewise can be removed and replaced as required. The closure 40 is intended to provide access to within the cavity of the intake 30 adjacent to the inlet of the pipe 35 through the body 32, so that the pipe 35 and associated components can be readily accessed.

(19) FIG. 5 shows the intake 30 in exploded view and this view shows that the annular body 32 includes an opening 42 through which the pipe 35 extends. The pipe 35 thus extends into the cavity 58 within the housing 31, through the opening 42 of the body 32 and the pipe 35 extends to a coupling 43 and to a pipe intake 44. Alternatively, the pipe 35, the coupling 43 and the pipe intake 44 can be formed integrally.

(20) As shown in FIG. 6, the intake 44 includes a downwardly facing intake opening 45 which in use, is below the surface of the liquid within the cavity 58 when the intake 30 is submerged in a body of liquid. It is to be noted however, that the downward facing orientation of the pipe opening 45 is not critical, and that it could alternatively open upwardly.

(21) The annular body 32 is shown in cross-section in FIGS. 6, 7 and 8, and in particular from FIGS. 6 and 8, it can be seen that the body 32 is formed as a hollow body which is shown filled with a buoyant material 46. This arrangement of filling the hollow annular body 32 with a buoyant material 46 is optional, but as explained earlier, the use of a buoyant material 46 can improve both the rigidity of the annular body 32 and can prevent the intake 30 from sinking in the event of rupture of the wall of the annular body 32.

(22) FIG. 9 shows the annular body 32 in isolation and that figure, it can be seen that the annular body 32 includes upper and lower surfaces 48 and 49 and inner and outer edges 50 and 51. The inner edge 50 forms an inner surface of a lower ring 52 which is connected by webs 53 to an upper ring 54. The opening 42 is formed in a tube 55 that extends through the lower and upper rings 52 and 54. The tube 55 is intended to be almost entirely submerged when the liquid intake 30 is operational as shown in FIG. 10. The lower and upper rings 52 and 54 are separated by an annular inlet 36 which is interrupted only by the webs 53 and by the inlet tube 55. As shown in FIG. 8, the outer diameter of the lower ring 52 is less that the inner diameter of the upper ring 54. The annular inlet 36 forms the inlet for entry of liquid into the cavity 58 during use of the liquid intake 30 and can be overlaid by the screens 37 illustrated in FIGS. 3, 5 and 7, as required.

(23) It will be evident from FIGS. 5, 6 and 7, that the housing 31 forms the internal cavity 58 between the upper and lower covers 33 and 34, and the annular body 32. Moreover, the pipe opening 45 of the pipe intake 44 is positioned generally centrally of the cavity, or centrally of the annular body 32. That central positioning of the opening 45 means that in a stationary body of water, water is entrained into the cavity 58 from the same distance around the opening 45. FIG. 10 illustrates the liquid intake 30 in an in use condition, and the arrows A indicate the direction in which water is entrained into the cavity 58 and it can be seen that the arrows extend completely about the circumference of the intake 30. Moreover, FIG. 10 shows the upper level of the body of water within which the intake 30 is submerged and it can be seen from this, that the annular inlet 36 is completely submerged within the body of water. Assuming that there are no other air intake areas, so that the connection between the upper cover 33 and the annular body 32 is generally airtight, and that the covers 39 and 40 of the upper cover 33 are in place, then the only entrance into the cavity 58 is through the screens 37 and the annular inlet 36. This tends to generate a vacuum within the cavity of the housing 31 which tends to raise the level of liquid within the cavity 58 relative to the level of the body of water within which the intake 30 is submerged. Depending on the volume being pumped, substantially the entire cavity 58 can be filled with liquid.

(24) As is explained earlier herein, by entraining water into the cavity 58 through the annular inlet 36, the effect is that liquid enters the pipe intake 44 from the side, rather than from directly below (or directly above if the pipe opening 45 faces upwardly rather than downwardly). As explained earlier herein, the intake 30 can prevent the formation of vortices by the direction of travel of liquid into the pipe intake 44, that being from the side rather than above or below, while the annular body 32 itself disrupts the formation of vortices from outside the intake 30. Vortices are therefore prevented or minimised to the extent that they do not cause any damage to the pumping station to which the pipe 35 extends, thus dealing with a major difficulty associated with prior art arrangements of the kind shown in FIG. 1.

(25) In addition, the position of the intake 30 at the surface of the body of water means that the water being entrained is the cleanest water in that body.

(26) In order for the intake 30 to submerge in a body of water, it is necessary for the air within the cavity 58 to be exhausted upon placement of the intake on to the surface of the body of water. Air can initially exhaust through the annular inlet 36, but water will soon cover the inlet 36 completely and so further exhaust through the inlet 36 is not possible. The present invention thus employs an arrangement in which a column 61 is employed and the operation of that column is explained later herein.

(27) FIG. 7 also shows ribs or baffles 65 that have been included in the lower cover 34 and that extend upwardly from the cover 34 into the cavity 58. The baffles 65 are intended to resist movement of liquid within the cavity 58, in particular swirling movement, during operation of the liquid intake 30. That movement can generate air bubbles which can become entrained within the liquid entering the pipe intake 45 and so minimising the liquid movement is advantageous, noting that there must be some movement within the cavity 58 for the liquid to be removed via the liquid intake 30.

(28) The intake 30 has been designed for use with a suction pumping system in which a suction pump or pumps are positioned remote from the intake on land, or on a floating body, such as a pontoon or barge, and are connected to the intake 30 via an intake pipe 35, or another pipe or conduit connected to the intake pipe 35. The distance between the suction pump or pumps and the liquid intake 30 can be in the order of 10 to 30 meters.

(29) Suction pumps have a limitation in that they have a theoretical maximum lift of no more than about 10 m. This assumes a perfect vacuum and very few friction losses and in practice, the suction lift is less than this. While that level of lift is suitable for many applications, if a greater lift is required, than the present invention can employ a submersible pump within the cavity 58 and this arrangement is illustrated in FIG. 11.

(30) In FIG. 11, the liquid intake 30 of the earlier figures has been modified to form the liquid intake 70 in which the pipe intake 44 is removed and to include a submersible pump 75 which is positioned centrally of the liquid intake 70 and beneath the closure 39. The submersible pump 75 is of a known form and includes a discharge outlet 76 that connects to a pipe 77. The pipe 77 is of a reduced diameter compared to the pipe 35 of the earlier figures and is supported within the opening 42 of the tube 55 by a pair of brackets 78 (see also FIG. 12 in which the submersible pump 75 is not shown) that fill the opening 42 and include an opening through which the pipe 77 extends.

(31) The submersible pump 75 further includes a power cable 79 and a base plate 80 to secure the pump 75 within the cavity 58. An inlet 81 sits below the base plate 80 and liquid flows through the base plate 80, into the inlet 81 for discharge through the outlet 76. A vacuum chamber pipe 82 operates in the manner of the column 61 as hereinafter described to exhaust air from within the cavity 58 for pump priming purposes.

(32) Returning to FIG. 6, the liquid intake 30 is able to be primed via an opening 60 that extends through a wall of the pipe intake 44 and that communicates with a vertical column 61 that extends into connection with a central opening 62 (see FIG. 5). The column 61 provides structural rigidity to the pipe intake 44 by connecting the intake 44 with the centre of the upper cover 33, but the column 61 also includes an opening in the region of reference numeral 63 and that opening 63 allows air to exhaust from within the cavity 58 as liquid enters the cavity 58, whereby the air passes into the column 61 through the opening at reference numeral 63, then downwardly through the column 61 and through the opening 60 into the intake 44. The air can then exhaust through the pipe 35. This process will continue until the level of liquid within the cavity 58 reaches the opening 60 in the intake pipe 44, so that no further exhaust of air through the column 61 can take place. However, upon generation of suction through the pipe 35, water rushing past the opening 60 will entrain air within the column 61 into the pipe 35, so that a vacuum will be generated within the column 61. This will tend to draw air through the opening at reference numeral 63 and into the column 61 and allow for the liquid level within the cavity 58 to rise. This is effectively how the vacuum is generated within the housing 31 of the intake 30 as discussed earlier herein. The entrainment of air within the within the column 61 into the pipe 35 only occurs briefly and is not continuing. Accordingly, there is no detriment to the operation of the liquid removal system by this small volume of air that is pumped through the system.

(33) Floating liquid intakes according to the present invention can be operated from land or water borne vehicles or structures.

(34) Floating liquid intakes according to the present invention can also permit significant reduction in the volume and surface area of ponds or dams, advantageously reducing losses through evaporation and reducing the land required for ponds or dams to be installed. FIG. 13 illustrates a comparison with an existing tailings dam and a tailings dam in which a liquid intake according to the present invention is employed. For this, the required radius and resultant area of decant pond and exposed tailings beach area were determined for two scenarios: a standard decant intake requiring a minimum 2 m pond depth, and a liquid intake according to the present invention requiring only 0.4 m minimum pond depth.

(35) The comparison between the two scenarios is: 1. Standard intake, 2 m pond depth: a. Required minimum pond radius around the decant intake: 133 m b. Resultant decant pond surface area: ˜70,500 m.sup.2 c. Exposed beach area: ˜179,500 m.sup.2 or 72% of total temporary storage facility (TSF) area. 2. Invention intake, 0.4 m pond depth: a. Required minimum pond radius around the decant station intake: 27 m b. Decant pond surface area: ˜2,300 m.sup.2 c. Exposed beach area: ˜247,700 m.sup.2 or 99% of total TSF (tailings dam) area.

(36) For this conceptual scenario, the use of the Invention intake allows the potential for 1. 96% reduction in the decant pond area, which also reduces evaporative losses from the pond itself by 96%. 2. At an example daily mean evaporation rate of 10 mm per day, this equates to a reduction in evaporative losses of 247 megalitres per year from the decant pond. 3. 38% increase in exposed tailings beach area, enhancing tailings drying with potential improvement in deposited density resulting in less frequent embankment raises and lower associated costs.

(37) The benefits of the Invention intake:

(38) TABLE-US-00001 Decant Barge, Decant Tower etc Invention intake Minimum pond radius 133 m 27 m Decant pond surface area ~70,500 m.sup.2 ~2,300 m.sup.2 Reduction in pond surface area 0% 96% Exposed beach area ~179,500 m.sup.2 ~247,700 m.sup.2 Exposed beach percentage 72% of total TSF area 99% of total TSF area Increase in exposed beach area 0% 38% Yearly evaporation saving 0 megaliters pa 247 megaliters pa

(39) This illustrates the potential magnitude of the benefit delivered by the Invention intake to an operation from environmental, reputational, risk management and economic perspectives. Similar benefits would also be evident in deployment of the Invention intake into other TSF configurations.

(40) Those skilled in the art will appreciate that the invention described herein is susceptible to variations and modifications other than those specifically described. It is understood that the invention includes all such variations and modifications which fall within the spirit and scope of the present invention.

(41) Where the terms “comprise”, “comprises”, “comprised” or “comprising” are used in this specification (including the claims) they are to be interpreted as specifying the presence of the stated features, integers, steps or components, but not precluding the presence of one or more other features, integers, steps or components, or group thereto.