FIELD OF THE INVENTION

The present invention relates to a method of manufac ^¬ turing an elbow channel with an elbow angle. Further, the invention relates to an elbow channel with an el ^¬ bow angle. BACKGROUND OF THE INVENTION

In prior art documents US 6176608, US 5662871 and US 6267900 there are disclosed elbow channels, such as a dispersion uptake shaft and outlet weir box (also com ^¬ monly called as an outlet box) which are used in con- nection with hydrometallurgical liquid-liquid solvent extraction settlers. An elbow channel comprises chan ^¬ nel parts which are at an angle to each other. Such elbow channel structures are traditionally manufac ^¬ tured as fiber-reinforced composite structures by hand lamination on a complicated hand-carved wooden mould. This kind of fabrication method is slow, cumbersome, time-consuming and costly. The manual fabrication method is also susceptible to quality variations de ^¬ pending on skills of the person making the lamination work. The mould can be used only once and it becomes waste after the elbow channel has been manufactured.

OBJECTIVE OF THE INVENTION

The objective of the invention is to eliminate the disadvantages mentioned above.

In particular, it is an object of the present inven ^¬ tion to provide a method which reduces manufacturing costs and simplifies and expedites the manufacturing process of the elbow channel. It is also an object of the present invention to pro ^¬ vide a method in which the mould to be used in manu ^¬ facturing can be repeatedly used. Further, it is an object of the present invention to provide an elbow channel which is cheaper than the hand laminated elbow channel and has reduced manufac ^¬ turing costs. SUMMARY OF THE INVENTION

According to a first aspect, the present invention provides a method of manufacturing an elbow channel with an elbow angle, the elbow channel being a fila ^¬ ment-reinforced plastic composite structure. In ac- cordance with the invention, the method comprises the steps of:

- manufacturing an elongated filament-reinforced plas ^¬ tic composite hollow body by a filament winding tech ^¬ nology,

- miter-cutting the elongated hollow body at a cut an ^¬ gle, which is half of the desired elbow angle, to form a first body piece having an oblique first end and a second body piece having an oblique second end,

- placing the first body piece and the second body piece in relation to each other to abut the first end and the second end against each other, so that the longitudinal symmetry axes of the first and second body pieces are at said elbow angle to each other, and

- attaching the first end and the second end to each other to form said elbow channel.

According to a second aspect, the present invention provides an elbow channel with an elbow angle, the el ^¬ bow channel being a filament-reinforced plastic compo- site structure. In accordance with the invention, the elbow channel is formed from first and second hollow body pieces which are miter cut at a cut angle, which is half of the desired elbow angle, from an elongated filament-wound filament-reinforced plastic composite hollow body and said hollow body pieces being connect ^¬ ed to each other at their miter cut oblique first and second ends to form said elbow channel.

The advantage of the invention is that the manufactur ^¬ ing time, cost of the elbow channel is reduced and the quality is improved. The mandrel used as a mould in the filament winding process can be used repeatedly no mould waste being generated from it.

In one embodiment of the method, the elongated hollow body is formed by the filament winding technology with the steps of:

- arranging an elongated mandrel the outside diameter of which corresponds to the inside diameter of the elongated hollow body to be formed, an

rotating the mandrel and simultaneously winding resin-impregnated filament in a number of lay ^¬ ers around and on the rotary mandrel to form the hol ^¬ low body with a desired wall thickness,

- curing the hollow body on the mandrel, and removing the cured hollow body from the mandrel.

In one embodiment of the method, the first end and the second end are laminated to each other. In one embodiment of the method, the method comprises arranging an opening to the wall of the elbow channel.

In one embodiment of the method, the method comprises attaching a closure at an end of the elbow channel.

In one embodiment of the method, the method comprises steps of: manufacturing an elongated filament- reinforced plastic composite second hollow body by a filament winding technology to form a launder for a liquid-liquid solvent extraction settler, so that the second hollow body has a total length which exceeds the first length of the launder at least by the second length of the hollow body, and

- cross-cutting the second elongated hollow body to form the launder with the first length and the hollow body with the second length, from which hollow body said elbow channel is formed.

In one embodiment of the method, the elbow channel is a dispersion uptake shaft of a feed launder which is for feeding a dispersion to a liquid-liquid solvent extraction settler.

In one embodiment of the method, the elbow channel is an outlet box of a discharge launder to receive a sep- arated solution phase which is discharged from a liq ^¬ uid-liquid solvent extraction settler.

In one embodiment of the method, the elbow angle is 90° or acute angle or obtuse angle.

In one embodiment of the elbow channel, the elbow an ^¬ gle is 90° or acute angle or obtuse angle.

In one embodiment of the elbow channel, the elbow channel is a dispersion uptake shaft of a feed launder which is for feeding the dispersion to a liquid-liquid solvent extraction settler.

In one embodiment of the elbow channel, the elbow channel is an outlet box of a discharge launder to re ^¬ ceive a separated solution phase which is discharged from a liquid-liquid solvent extraction settler. BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to pro- vide a further understanding of the invention and constitute a part of this specification, illustrate embodiments of the invention and together with the de ^¬ scription help to explain the principles of the inven ^¬ tion. In the drawings:

Figure 1 is a schematic illustration of the step of filament winding a hollow body for forming the elbow channel in accordance with an embodiment of the method of the invention,

Figure 2 shows the cured hollow body detached from the mandrel ,

Figure 3 shows the hollow body after being miter cut to a first and a second hollow body piece,

Figure 4 shows the elbow channel formed of the miter cut first and second hollow body piece being attached to each other,

Figure 5 shows the elbow channel after being equipped with a closure and two openings,

Figure 6 shows a schematic plan view of a solvent ex- traction settler arrangement having elbow channels formed to a dispersion uptake shaft and outlet boxes,

Figure 7 is a cross-section VII-VII of Figure 6 show ^¬ ing a dispersion feed launder and an elbow channel formed to a dispersion uptake shaft manufactured ac ^¬ cording to an embodiment of the method of the inven ^¬ tion, Figure 8 is a cross-section VIII-VII of Figure 6 showing a discharge launder and an elbow channel formed as an outlet box manufactured according to an embodiment of the method of the invention, and

Figure 9 shows a filament wound second hollow body from which a launder and a hollow body for an elbow channel can be cut.

DETAILED DESCRIPTION OF THE INVENTION

Figures 1 to 5 show different steps of manufacturing an elbow channel 1 having an elbow angle a. An elongated filament-reinforced plastic composite hollow body 2 is formed by a filament winding process, as shown in Figure 1. An elongated mandrel 7 is ar ^¬ ranged. The outside diameter of the mandrel 7 is di ^¬ mensioned so that it corresponds to the inside diame- ter of the elongated hollow body 2 to be formed. The mandrel 7 is rotated and simultaneously resin- impregnated filament 8 is wound in a number of layers on the rotating mandrel 7 to form the hollow body 2 with a desired wall thickness. After the winding pro- cess is completed, the resin of the hollow body 2 is cured while the hollow body is still on the mandrel 7. After the resin in the hollow body 2 has been cured, the hollow body 2 is removed from the mandrel 7. Figures 2 and 3 show miter-cutting of the elongated hollow body 2 along a plane which is at a cut angle a/2, which is half of the desired elbow angle a, to form a first body piece 3, which has an oblique first end 4, and a second body piece 5 which has having an oblique second end 6. In the illustrated example the elbow angle a is 90° and therefore the cut angle is 45°. In other not-shown embodiments the elbow angle a can be different than 90°, i.e. it can be an obtuse angle or an acute angle, as desired.

As shown in Figure 4, the first body piece 3 and the second body piece 5 are placed in relation to each other so that the first end 4 of the first hollow piece 3 and the second end 6 of the second hollow piece are abutting against each other, so that the longitudinal symmetry axes x of the first and second body pieces are at the elbow angle 90° to each other. The first end 4 and the second end 6 are attached to each other to form the elbow channel 1. The attachment of can be made e.g. by laminating. Figure 5 shows an example of an elbow channel 1 which is configured to include a closure 11 at the lower end of the first hollow piece 3. An opening 9 that enables access to the inner space of the elbow channel 1 (for e.g. sampling purposes) is arranged on top of the se- cond hollow piece 5 at a location above a vertical shaft which is formed by the inner space of the first hollow piece 3. Another opening 10 which opens laterally is arranged in the wall of the first hollow piece 3 to form an inlet to the inner space of the elbow channel 1, or alternatively to form an outlet from the inner space of the elbow channel, depending of the di ^¬ rection of the flow of the fluid which is to be con ^¬ ducted through the elbow channel 1. Figure 6 shows a solvent extraction settler arrange ^¬ ment which is adapted for hydrometallurgical liquid- liquid solvent extraction processes. The arrangement comprises a pump/mixing unit 18 and a solvent extrac ^¬ tion settler 15. The pump/mixing unit 18 includes, in this case, a pumping unit 19 and two mixers 20, 21. Two or more liquid phases that are insoluble in each other are mixed together into a dispersion in the pump 19. Pump 19 feeds the dispersion to mixer 20, from where it is routed on to the second mixer 21 and from thereon via a dispersion uptake shaft 16 to a feed launder 13 arranged along and beside the feed end 22. The dispersion feed launder 16 distributes the dispersion to the solvent extraction settler tank 15. The phases to be mixed into a dispersion in the arrange- ment may be a heavy solution, for instance an aqueous solution, and a light solution, for instance an organic solution. In dispersion the extraction reaction transfers for example metals from one phase to the other. The solution phases are separated by gravity from each other in the settler tank while they flow to a discharge end 23 of the settler tank 15. From the discharge end 23 the heavy solution phase flows as an underflow to the discharge launder 14, and the light solution phase flows as an overflow another discharge launder 14' . In the launders 14, 14' flow to one end of each discharge launder and further through the outlet boxes 17 which are arranged at the ends of the discharge launders to receive the solution phases. Figure 7 shows the dispersion feed launder 13 and the dispersion uptake shaft 16 connected to it. Figure shows the discharge launder 14 and the outlet box 17 connected to it. The launders 13, 14 are tubular and can be manufactured by filament winding. Both the dis- persion uptake shaft 16 and the outlet box 17 can be manufactured simultaneously with the launders 13, 14.

As shown in Figure 9, an elongated filament-reinforced plastic composite second hollow body 12 is manufac- tures by a filament winding technology, in a manner as disclosed in connection with Figure 1, to form a launder 13, 14, 14' so that the second hollow body 12 has a total length L which exceeds the first length li of the launder 13, 14, 14' at least by the second length I ₂ of the hollow body 2. Figure 2 shows a cured second hollow body 12. The second elongated hollow body 12 is cross-cut to form a part which forms the launder 13, 14, 14' with the first length li and another part which forms the hollow body 2 with the second length I ₂ . The elbow channel 1 is formed from the hollow body 2 to make a dispersion uptake shaft 16 or an outlet box 17, in a manner as disclosed above with reference to Fig ^¬ ures 2 to 5.

Although the method and the elbow channel have been described in connection with a solvent extraction set- tier, it should be understood that the method and the elbow channel are not so limited. Any elbow channel which is intended to conduct fluid, either in a form of liquid or gas, can be manufactured with the de ^¬ scribed method. While the present inventions have been described in connection with a number of exemplary embodiments, and implementations, the present inventions are not so limited, but rather cover various modifica ^¬ tions, and equivalent arrangements, which fall within the purview of prospective claims.