Screw feeder for roller compactor machine
A screw feeder is provided for a powder roller compactor machine. The machine includes a hopper for holding powder and a pair of rollers for compacting the powder. A screw feeder transfers powder from the hopper to the rollers. The screw feeder includes an upper tapered section with a tapered shaft and a lower straight section with a straight shaft. Auger flighting is provided on the tapered and straight sections of the screw feeder. The auger flighting preferably has a fixed depth along the length of the screw feeder.
1. An improved roller compactor machine having rollers for compacting powdered material, and a hopper for feeding the material to the rollers, the improvement comprising:
a screw feeder mounted inside the hopper and having an upper tapered section, and a lower straight section;
the tapered section having upstream and downstream ends and a tapered shaft with a diameter being greater at the upstream end than the downstream end;
auger flighting extending along the tapered shaft of the tapered section for more than 360° and along the straight section for more than 360°.
2. The improved machine of claim 1 wherein the flighting has a substantially constant depth along the tapered section.
3. The improved machine of claim 1 wherein the auger flighting on the straight section of the screw feeder has substantially constant depth.
4. The improved machine of claim 3 wherein the depth of the flighting on the tapered and straight sections are substantially equal in depth.
5. The improved machine of claim 1 wherein the tapered shaft narrows at approximately a 30° angle from the upstream end to the downstream end.
6. The improved machine of claim 1 wherein the tapered section of the screw feeder is within the hopper and the straight section of the screw feeder extends out of the hopper.
7. A powder roller compactor machine, comprising:
a hopper for holding powder;
a pair of rollers for compacting powder;
a screw feeder for transferring powder from the hopper to the rollers;
the screw feeder having a shaft with a tapered section within the hopper and a straight section extending out of the hopper;
the screw feeder having flighting on the shaft sections; and the flighting on the straight section residing outside the hopper along a portion of its length.
8. The compactor machine of claim 7 wherein the tapered shaft section narrows from an upstream end to a downstream end.
9. The compactor machine of claim 7 wherein the flighting has a fixed depth.
10. The compactor machine of claim 7 wherein the tapered shaft section tapers at an angle of approximately 30°.
11. The improved machine of claim 1 wherein a portion of the straight section of the screw feeder resides outside the hopper.
12. The compactor machine of claim 7 wherein the flighting extends more than 360° on each feeder section.