Separator for a grinding machine

1. A grinding machine comprising:

a grinding head defining an opening;

a rotatable advancement member contained within the grinding head;

an orifice plate located within the opening of the grinding head, wherein the orifice plate defines an upstream surface and a downstream surface, and includes a plurality of outer grinding openings extending between the upstream surface and the downstream surface for discharging soft material through the orifice plate upon rotation of the rotatable advancement member, and one or more collection passages extending between the upstream surface and the downstream surface for discharging a mixture of soft material and hard material through the orifice plate upon rotation of the rotatable advancement member; and

a separator assembly located downstream of the orifice plate, wherein the separator assembly includes an upstream inlet that receives the mixture of soft material and hard material from the collection passages; a separator chamber having a wall that defines an axially extending tapered separator passage, wherein the separator passage receives the mixture of soft material and hard material from the upstream inlet, and wherein the wall of the separator chamber includes a plurality of perforations that communicate between the separator passage and an outer surface defined by the wall; and a separator screw disposed within the separator passage of the separator chamber, wherein the separator screw is interconnected with the rotatable advancement member and is rotatable within the separator passage in response to rotation of the rotatable advancement member, wherein rotation of the separator screw causes separation of soft material from the mixture of soft material and hard material and forces the soft material through the perforations in the wall of the separator chamber, wherein the separator chamber defines a downstream end that includes an outlet for discharging hard material;

wherein the separator chamber has a first tapered portion and a second tapered portion, and wherein the first tapered portion defines a collection cavity into which mixture of soft material and hard material is passed through the one or more collection passages of the orifice plate, and wherein the second tapered portion extends from the first tapered portion.

2. The grinding machine of claim 1 , wherein the wall of the separator chamber has a generally conical configuration.

3. The grinding machine of claim 1 , wherein the perforations are formed in the second tapered portion of the separator chamber.

4. The grinding machine of claim 3 , wherein the downstream end of the separator chamber defines a constant diameter portion adjacent the outlet, wherein the perforations are located upstream of the constant diameter portion.

5. A grinding machine comprising:

a grinding head defining an opening;

a rotatable advancement member contained within the grinding head;

an orifice plate located within the opening of the grinding head, wherein the orifice plate defines an upstream surface and a downstream surface, and includes a plurality of outer grinding openings extending between the upstream surface and the downstream surface for discharging soft material through the orifice plate upon rotation of the rotatable advancement member, and one or more collection passages extending between the upstream surface and the downstream surface for discharging a mixture of soft material and hard material through the orifice plate upon rotation of the rotatable advancement member;

a separator assembly located downstream of the orifice plate, wherein the separator assembly includes an upstream inlet that receives the mixture of soft material and hard material from the collection passages; a separator chamber having a wall that defines an axially extending tapered separator passage, wherein the separator passage receives the mixture of soft material and hard material from the upstream inlet, and wherein the wall of the separator chamber includes a plurality of perforations that communicate between the separator passage and an outer surface defined by the wall; and a separator screw disposed within the separator passage of the separator chamber, wherein the separator screw is interconnected with the rotatable advancement member and is rotatable within the separator passage in response to rotation of the rotatable advancement member, wherein rotation of the separator screw causes separation of soft material from the mixture of soft material and hard material and forces the soft material through the perforations in the wall of the separator chamber, wherein the separator chamber defines a downstream end that includes an outlet for discharging hard material; and

a centering pin extending from the rotatable advancement member, wherein the centering pin rotates with the rotatable advancement member and is engaged within a center opening defined by the orifice plate, and wherein the separator screw is engaged with the centering pin so as to be rotatable with the rotatable advancement member via engagement with the centering pin.

6. The grinding machine of claim 5 , including engagement structure between the centering pin and the separator screw for non-rotatably securing the separator screw to the centering pin.

7. The grinding machine of claim 6 , further comprising an adjustment arrangement for adjusting the axial position of the separator screw within the separator passage, wherein the engagement structure between the separator screw and the centering pin accommodates axial movement of the separator screw relative to the centering pin by operation of the adjustment arrangement.

8. The grinding machine of claim 7 , wherein the engagement structure comprises a bore in the separator screw within which the centering pin is received; a transverse passage in the centering pin; a slot in the separator screw that overlaps the transverse passage; and a transverse engagement pin that extends through the slot and the transverse passage, wherein the slot accommodates axial movement of the separator screw relative to the centering pin.

9. A separator arrangement for a grinding machine that includes a grinding head, a rotatable advancement auger located within the grinding head, an orifice plate located within an opening defined by the grinding head, and a knife arrangement driven by the auger, comprising:

a support arrangement adapted for interconnection with the grinding head and defining a support area positioned outwardly of the orifice plate;

a separator chamber having a wall that defines an axially extending tapered separator passage, wherein the separator defines an upstream end adapted for engagement with the orifice plate and a downstream end adapted for engagement with the support area of the support arrangement, wherein the separator passage is adapted to receive a mixture of soft material and hard material discharged by the orifice plate, wherein the wall of the separator chamber includes a plurality of perforations that communicate between the separator passage and an outer surface defined by the wall; and

a separator screw disposed within the separator passage of the separator chamber, wherein the separator screw is adapted for interconnection with the rotatable advancement auger and is rotatable within the separator passage in response to rotation of the rotatable advancement auger, wherein rotation of the separator screw causes separation of soft material from the mixture of soft material and hard material and forces the soft material through the perforations in the wall of the separator chamber, wherein the downstream end of the separator chamber includes an outlet for discharging hard material from the separator passage;

wherein the grinding machine includes a centering pin extending from the rotatable advancement auger, wherein the centering pin rotates with the rotatable advancement auger and is engaged within a center opening defined by the orifice plate, and wherein the separator screw is adapted for engagement with the centering pin so as to be rotatable with the rotatable advancement auger via engagement with the centering pin.

10. The separator arrangement of claim 9 , including engagement structure between the centering pin and the separator screw for non-rotatably securing the separator screw to the centering pin.

11. The separator arrangement of claim 10 , further comprising an adjustment arrangement for adjusting the axial position of the separator screw within the separator passage, wherein the engagement structure between the separator screw and the centering pin accommodates axial movement of the separator screw relative to the centering pin by operation of the adjustment arrangement.

12. The separator arrangement of claim 11 , wherein the engagement structure comprises a bore in the separator screw within which the centering pin is adapted to be received; a transverse passage in the centering pin; a slot in the separator screw that overlaps the transverse passage; and a transverse engagement pin that extends through the slot and the transverse passage, wherein the slot accommodates axial movement of the separator screw relative to the centering pin.

13. A separator arrangement for a grinding machine that includes a grinding head, a rotatable advancement auger located within the grinding head, an orifice plate located within an opening defined by the grinding head, and a knife arrangement driven by the auger, comprising:

a support arrangement adapted for interconnection with the grinding head and defining a support area positioned outwardly of the orifice plate;

a separator chamber having a wall that defines an axially extending tapered separator passage, wherein the separator defines an upstream end adapted for engagement with the orifice plate and a downstream end adapted for engagement with the support area of the support arrangement, wherein the separator passage is adapted to receive a mixture of soft material and hard material discharged by the orifice plate, wherein the wall of the separator chamber includes a plurality of perforations that communicate between the separator passage and an outer surface defined by the wall;

a separator screw disposed within the separator passage of the separator chamber, wherein the separator screw is adapted for interconnection with the rotatable advancement auger and is rotatable within the separator passage in response to rotation of the rotatable advancement auger, wherein rotation of the separator screw causes separation of soft material from the mixture of soft material and hard material and forces the soft material through the perforations in the wall of the separator chamber, wherein the downstream end of the separator chamber includes an outlet for discharging hard material from the separator passage; and

an adjustment arrangement for adjusting the axial position of the separator screw within the separator passage.

14. The separator arrangement of claim 13 , wherein the support and the orifice plate are configured and arranged to prevent axial movement of the separator chamber, and wherein the adjustment arrangement is carried by the support and interconnected with the separator screw for providing axial movement of the separator screw within the separator passage.

15. The separator arrangement of claim 14 , wherein the adjustment arrangement comprises an axially extending threaded adjustment member that extends through the support and into engagement with a threaded passage extending inwardly from a downstream end defined by the separator screw.