Pocket Wheel Granule Delivery for Asphalt Shingle Production
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Solution Overview
Problem
Existing granule delivery systems for asphalt shingles are limited by their inability to maintain precise and defined patterns of granules at production speeds above 800 feet per minute, resulting in unacceptable trailing edges and distortion, which restricts manufacturing speeds.
Innovation Solution
A granule delivery system utilizing a cylindrical pocket wheel with indexed rotation and a brush seal to consistently dispense granules in a controlled pattern, allowing for precise deposition at higher speeds by coordinating the pocket wheel's speed with the asphalt strip's speed and using fluted pockets for enhanced definition and control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional granule drop technologies are used, then granules can be dispensed onto the asphalt coated strip, but the production speed is limited to below 800 feet per minute due to pattern distortion and smeared trailing edges
Solution Approach 1:
The granule delivery system divides the granule flow into discrete charges using a fluted roll with grooves that segment the continuous granule stream into individual deposits. Each flute acts as a separate channel that controls granule flow timing and placement, enabling precise pattern definition even at high production speeds exceeding 800 feet per minute.
2Productivity
If the speed of the moving asphalt coated strip is increased to improve productivity, then more shingles can be produced per unit time, but the edges and patterns of dispensed granules become less defined and more distorted
Solution Approach 1:
The fluted roll is designed to rotate at a speed coordinated with the moving asphalt coated strip, creating a dynamic system where the granule delivery rate automatically adjusts to match production speed. The rotational motion of the fluted roll synchronizes granule discharge timing with strip movement, maintaining crisp pattern edges and preventing trailing edge smear even as production speed increases.
3Ease of operation
If a fluted roll is used to deliver granules in spaced patterns, then granules can be deposited at controlled intervals, but the trailing edges of deposited charges become smeared out at high production speeds
Solution Approach 1:
The fluted roll delivers granules through periodic action, where each rotation cycle produces discrete charges of granules at regular intervals determined by the flute spacing and roll rotation speed. This periodic delivery mechanism creates well-defined granule patterns with sharp trailing edges, as each flute releases its granule charge in a controlled, time-limited manner that prevents smearing even at high production speeds.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system achieves well-defined, uniform granule patterns with crisp edges and minimal distortion at production speeds exceeding traditional limits, up to 1000 feet per minute, ensuring high-quality shingle production.
Implementation Method 1
A brush seal is located at the bottom of the hopper and includes brushes or other sealing members positioned to ride on the lands of the pocket wheel as the lands are rotated past the brush seal. The brush seal also rides across the open pockets as the pockets rotate out of the hopper to level a charge of granules collected by the pockets
Implementation Method 2
The curved surface in conjunction with gravity accelerates the charge of granules to approximately the speed of the moving asphalt coated strip below and deposits the charge of granules gently onto the asphalt
Data Source
AI summary
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 in the bottom of the hopper. A series of pockets are formed in the circumference of the wheel and the pockets are separated by raised lands. A seal on the bottom of the hopper 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 bottom of the hopper. 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. The speed at which the wheel is indexed is coordinated with the speed of the asphalt coated strip so that granules and strip are moving at about the same forward speed or at a preselected ratio of speeds when the granules fall onto the strip. Well defined patterns of granules are possible at high production rates.