High speed granule delivery system and method
View Patent ↗A high speed granule delivery system and method is disclosed for dispensing granules in intermittent patterns onto a moving asphalt coated strip in the manufacture of roofing shingles. The system includes a granule hopper and a rotationally indexable pocket wheel having an alternating series of pockets and lands formed into the circumference thereof, and which is positioned adjacent a nozzle in the bottom of the hopper. Upper and lower side portions of the pocket wheel define and are exposed to upper and lower extents of a store of granules. A seal on the bottom of the lower extent of the store of granules seals against the raised lands as the wheel is indexed. In use, the pockets of the pocket wheel drive through and are filled with granules in the store of granules. As each pocket is indexed beyond the seal, it is exposed to the moving asphalt coated strip below and its granules fall onto the strip to be embedded in the hot tacky asphalt.
1. A method of depositing granules in a preselected pattern onto a moving web, the method comprising the steps of:
(a) establishing a store of granules having an upper extent and a lower extent above a moving web;
(b) obtaining a pocket wheel having an axis of rotation and at least one granule pocket formed in a peripheral surface of the pocket wheel;
(c) locating the pocket wheel above the moving web such that the axis of rotation of the pocket wheel is between the upper extent and the lower extent of the store of granules and a portion of the peripheral surface of the pocket wheel is exposed to the store of granules;
(d) rotating the pocket wheel to move the at least one pocket into the upper extent of the store of granules such that the pocket collects a charge of granules from the store;
(e) further rotating the pocket wheel to move the at least one pocket downward into the lower extent of the store of granules such that the granules within the store maintain the charge of granules within the at least one pocket;
(f) further rotating the pocket wheel until the at least one pocket begins to emerge from the lower extent of the store of granules and as a result of emerging from the lower extent of the store of granules, begins to become exposed to the moving web below;
(g) further rotating the pocket wheel to move the pocket containing the charge of granules through an inverted orientation above the moving web;
(h) allowing the charge of granules to fall from the pocket onto the moving web as the pocket moves through the inverted orientation; and
(i) repeating steps (d) through (h) to deposit successive charges of granules onto the moving web.
2. The method of claim 1 where in step (g) the pocket is moved through the inverted orientation at a speed that matches or that is a predetermined ratio of the speed of the moving web below.
3. The method of claim 1 further comprising leveling the charge of granules in the pocket as the pocket emerges from the lower extent of the store in step (f) to insure a substantially uniform volume of the charge prior to step (h).
4. The method of claim 3 wherein the step of leveling comprises progressively moving the pocket past a seal as the pocket emerges from the lower extent of the store.
5. A method of depositing granules onto a moving asphalt coated web in the manufacturing of roofing shingles, the method comprising the steps of:
(a) establishing a store of granules with the store having an upper extent and a lower extent located above the moving asphalt coated web;
(b) moving a pocket in a downward direction through the upper extent of the store of granules such that the pocket collects a charge of granules from the store;
(c) further moving the pocket in a downward direction through the lower extent of the store of granules such that the granules within the store maintain the charge of granules within the pocket;
(d) further moving the pocket in a downward direction until the pocket and granules collected therein progressively emerge from the lower extent of the store of granules and as a result of emerging begin to be exposed to the moving asphalt coated web;
(e) further moving the pocket progressively through an inverted orientation to allow the granules collected in the pocket to fall from the pocket onto the moving asphalt coated web below; and
(f) repeating steps (b) through (e) to deposit additional successive collections of granules onto the moving asphalt coated web below.
6. The method of claim 5 wherein the pocket is formed on a peripheral surface of a rotatable pocket wheel and wherein steps (b) through (e) comprise rotating the pocket wheel.
7. The method of claim 6 wherein multiple pockets are formed on the peripheral surface of the pocket wheel and wherein steps (b) through (e) are carried out with each pocket.
8. The method of claim 5 further comprising a step of metering a volume of granules in the pocket as the pocket emerges from the lower extent of the store of granules.
9. The method of claim 6 wherein the step of metering the volume of granules comprises moving the pocket past a seal situated at the lower extent of the store of granules.
10. The method of claim 5 where in step (e) the pocket is moved at a speed that is substantially the same as the speed of the moving asphalt web.
11. The method of claim 5 were in step (e) the pocket is moved at a speed that is faster than the speed of the moving asphalt web.
12. The method of claim 5 where in step (e) the pocket is moved at a speed that is slower that the speed of the moving asphalt web.
13. The method of claim 5 wherein steps (b) through (e) are carried out during a continuous movement of the pocket.
14. The method of claim 5 wherein steps (b) through (e) are carried out through intermittent movements of the pocket.