Field of the Invention

The present invention relates to spiral separators used for separating particulate materials having different specific gravities, and specifically to spiral separators having a splitter assembly adjacent the discharge end of a volute adapted to segregate the material separated by the spiral separator.

Description of the Prior Art

In some separators the blade is mounted for translation in a radial direction as is described in Australian Application 37175/78. Other separators have been provided with a splitter blade which is mounted for rotation about an axis normal to the floor of the volute, that is to say substantially parallel to the axis of the volute. In such cases the position of separation is adjusted by rotating the splitter blade about its axis. A portion of the splitter blade upstream of the axis, upon rotation, traverses the volute, and so adjustment is achieved.

Splitter assemblies as above described are adequate in some respects. However, when such splitter assemblies are used in multiple spiral separators which have more than one volute, whether the volutes are disposed in multi-start threaded arrangement or in adjacently wrapped arrangement, the separate adjustment of all splitters is tedious and inaccurate, and if an interlinking mechanism is installed, is complex. This complexity is undesirable as such mechanisms are expensive to manufacture, and difficult to maintain, particularly in harsh environments such as are commonly found in the vicinity of spiral separators.

It is an .object of the present invention to overcome or at least ameliorate the shortcomings of the prior art by simple means. Summary of the Invention

The present invention consists in a spiral separator comprising: a volute; a splitter blade mounted below a discharge section of the volute for selected rotation about a substantially horizontal axis tangential to the direction of flow in the volute, splitting being adjusted by the rotation of said splitter blade about said axis.

In a preferred form, the spiral separator includes a compartmented collection vessel below the discharge

section of the volute. When a plurality of spiral separators are disposed in a linear array, the corresponding splitters may be mounted on a common axis and a common collection vessel may be used for all of the separators in the array. Brief Description of the Drawings

The present invention will now be described by way of example only with reference to the accompanying drawings in which:

Figure 1 is an end elevation of a spiral separator according to the present invention;

Figure 2 is an enlarged, partly sectioned segment of part of the spiral separator of Figure 1, and;

Figure 3 is a side elevation showing two spiral separators according to the present invention in linear array. Description of the Preferred Embodiment

Referring to the drawings, a spiral separator 1 comprises a volute 2 having a discharge end 3, and two splitter blades 4 at the discharge end 3. The splitter blades 4 are each mounted for selected rotation about substantially horizontal axes 5 which extend below the volute and tangential to a direction of flow within the volute at the discharge and 3. That is to say, the axis extend in a direction substantially parallel to the direction of motion of particulate material leaving the discharge end 3 of the volute 2. Rotation of the

splitter blades 4 about axes 5, as indicated by arrows 6, effects the adjustment of the location of separation at the discharge end 3 of the volute 2.

A compartmented collection vessel 7 is located below the splitter blades 4 to collect material separated by the splitter blades 4.

The inclination of the splitter blades 4 may be adjusted and set by a lockable operating lever 8 which is connected with the splitter blades 4 by a shafts 9.

A plurality of spiral separators according to the present invention may be arranged in linear array, in which case a single shaft 9 as shown in Figure 3 may operate a like plurality of ganged splitter blades 4. In this case the collection ^* vessel 7 extends beneath each of the separators in the linear array. If the ground on which the array is located is inclined then the substantailly horizontal axis 5 may be equally inclined.

The present invention extends to spiral separators having two or more volutes disposed one above the next. In such cases two sets of splitter blades and corresponding control mechanisms may be required.

The volutes may terminate in a sharp edge to ensure clean discharge without undesireable flow attachment. This edge may be formed to permit clearance between the splitter and the edge. If the edge is formed from a resiliant material slight interference may be beneficial,

Whilst the splitter blades, shown herein, are of the simplest shape, it is envisaged that they may be modified, for instance, to increase in height in the direction of flow, or to include baffles to assist in diverting the flow from the volute into the collection vessel.