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Feed Hopper Apparatus For Use in Manufacturing Processes

IP.com Disclosure Number: IPCOM000186722D
Publication Date: 2009-Aug-31
Document File: 9 page(s) / 133K

Publishing Venue

The IP.com Prior Art Database

Abstract

[0001] Described herein is a feed hopper vessel for delivery of materials to a manufacturing process which includes a dust collection portion having filter media contained therein, a settling portion, an inlet for feeding materials to the hopper, and a hopper portion. In one or more embodiments, the diameter of the dust collection portion, the diameter of the hopper portion, and the height of the settling portion are equal. In another embodiment, the gas-to-cloth ratio in the dust collection portion is less than 3 acfm per square foot. In a further embodiment, the can velocity in the dust collection portion is less than 300 ft/min.

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FEED HOPPER APPARATUS FOR USE IN MANUFACTURING PROCESSES

ABSTRACT

[0001]               Described herein is a feed hopper vessel for delivery of materials to a manufacturing process which includes a dust collection portion having filter media contained therein, a settling portion, an inlet for feeding materials to the hopper, and a hopper portion.  In one or more embodiments, the diameter of the dust collection portion, the diameter of the hopper portion, and the height of the settling portion are equal.  In another embodiment, the gas-to-cloth ratio in the dust collection portion is less than 3 acfm per square foot.  In a further embodiment, the can velocity in the dust collection portion is less than 300 ft/min.    

BACKGROUND

[0002]      In many manufacturing processes, an apparatus is employed to feed materials to the start of the process.  Such apparatus are commonly referred to, and are referred to herein, as feed hoppers.  Use of a feed hopper allows for constant, efficient, and simple delivery of materials to a continuous process, including for example extrusion processes such as those commonly used in the manufacture of polymer products.  Commonly, hoppers that are used to feed granular or particulate materials include a dust collection unit attached above the hopper vessel to minimize the amount of dust released to the environment as a result of the feeding process. 

[0003]               A common technique to determine the required dimensions of feed hoppers utilizes the settling velocity of the particles being fed to a manufacturing process.  The settling velocity of an additive particle is based on Stoke’s Law for small particles and laminar flow and is calculated using the following equation:

Vs = (g*(Ps–Pg)*d) / (18*µ),

where Vs is the settling velocity in ft/s, g is the gravitational constant 32.2 ft/s2, Ps is the density of the solid particles in lb/ft3, Pg is the density of the vent gases in lb/ft3, d is the particle diameter in ft, and µ is the viscosity of the vent gases in lb/ft-s.  Once the settling velocity is determined, gas volume may be calculated and, from that, the required diameter of the hopper. 

[0004]               Basing the diameter of the feed hopper on the settling velocity in this manner results in extremely large hopper vessels.  For example, for a typical polymer extrusion process producing 300 kilotons of finished product per year, a hopper vessel (including an attached dust collection unit) would be more than seven feet in diameter and over twenty-two feet in height, and the diameter of the hopper portion of the vessel would be more than twice that of the dust collection portion.  While such a configuration advantageously results in light loading on the dust collector and continuous settling of additives and fines within the hopper vessel, any advantages of the prior art design are outweighed by...