Apparatus for conveying material in a dispensing system
An apparatus for conveying material in a dispenser system is disclosed. The apparatus comprises a centerless auger or helix with one or more helical conveying members having a small cross-sectional diameter, a large outer diameter, and a long pitch.
1 . An apparatus for conveying material in a dispenser system, the apparatus comprising:
a driven hub;
a first helical conveying member having a first end coupled to the driven hub;
wherein the first helical conveying member forms an outer diameter and a pitch such that the ratio of the pitch to the outer diameter is at least four.
2 . The apparatus of claim 1 wherein the ratio of the pitch to the outer diameter is between about four and about ten.
3 . The apparatus of claim 1 wherein the pitch is uniform along the entire length of the first helical conveying member.
4 . The apparatus of claim 1 further comprising a second helical conveying member having a first end coupled to the driven hub.
5 . The apparatus of claim 4 wherein the first helical conveying member and the second helical conveying member provide two discharges of material per revolution of the apparatus.
6 . The apparatus of claim 5 further comprising a discharge hub wherein the first helical conveying member comprises a second end coupled to the discharge hub, and the second helical conveying member comprises a second end coupled to the discharge hub.
7 . The apparatus of claim 6 further comprising one or more discharge members having a first end coupled to the discharge hub and a second end extending toward the driven hub and engage the material and provide additional discharges of the material per revolution of the apparatus.
8 . The apparatus of claim 1 further comprising one or more members having a first end coupled to the driven hub and a second end extending towards the discharge hub.
9 . The apparatus of claim 1 wherein the first helical conveying member and the second helical conveying member are rods with a circular cross-section.
10 . The apparatus of claim 9 wherein the rods have a cross-sectional diameter of less than ¼ inch.
11 . A system for dispensing a material comprising:
a hopper configured to contain the material;
a feeder configured to receive the material from the hopper and comprising:
a nozzle having an inlet in communication with the hopper and a discharge outlet; and
a conveying apparatus disposed at least partially in the nozzle and having a first conveying member, a second conveying member and one or more discharge members coupled to and extending from the discharge end of the conveying apparatus and extending in the nozzle toward the inlet.
12 . The system of claim 11 wherein the first conveying member and the second conveying member form an outer diameter and a pitch such that the ratio of the pitch to the outer diameter is at least four.
13 . The system of claim 11 wherein the first conveying member and the second conveying member form an outer diameter and the nozzle comprises an inside diameter greater than the outer diameter of the first conveying member and the second conveying member.
14 . The system of claim 11 wherein the first helical conveying member and the second helical conveying member contact the inner wall of the nozzle.
15 . The system of claim 14 wherein the first helical conveying member and the second helical conveying member are in a biased condition when mounted in the nozzle.
16 . The system of claim 15 wherein the nozzle includes an inner diameter that is smaller than the outer diameter of the first conveying member and the second conveying member.
17 . The system of claim 11 wherein the ratio of the pitch to the outer diameter is between about four and about ten.
18 . The system of claim 11 further comprising a discharge chute located at the discharge outlet of the nozzle and configured to guide the discharged material at least partially toward the driven hub.
19 . The system of claim 18 wherein the discharge chute is conically shaped and comprises a smaller diameter end coupled to the discharge hub and a larger diameter end extending toward the driven hub.
20 . The system of claim 19 wherein the conical chute is coupled to the discharge end of the conveying apparatus.
21 . The system of claim 11 wherein the one or more discharge members comprises a first discharge member and a second discharge member, each discharge member having a first end coupled to the discharge hub and a second end extending toward the driven hub and are configured to engage the material and provide two additional discharges of the material per revolution of the conveying apparatus.
22 . A method for dispensing material having an angle of repose of 30 degrees or more at a feed rate of less than 200 grams per hour, the method comprising:
providing a hopper, a nozzle coupled to the hopper, and a centerless helix disposed in the nozzle, the centerless helix having one or more members extending from a discharge end of the centerless helix toward the inlet end of the centerless helix, and two or more conveying members providing a pitch, an outer diameter, and a pitch to outer diameter ratio of more than four;
rotating the centerless helix and moving material from the hopper and through the nozzle;
providing a first discharge of material from the nozzle per revolution of the centerless helix from the at least one discharge member;
providing a second discharge and a third discharge of material from the nozzle per revolution of the centerless helix from the two or more convey members.
23 . The method of claim 22 wherein the step of rotating the centerless helix comprises rotating the centerless helix between about 1 rpm and about 200 rpm.
24 . The method of claim 22 further comprising dispensing the material onto a conical dispensing chute coupled to the centerless helix.