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US 4,729,176 AGranted
Rotary drum dryer and method
AssigneeProductization, Inc.
InventorsDonald E. Shinn, Andrew D. Livingston
Life of this patent
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AssigneeProductization, Inc.
InventorsDonald E. Shinn, Andrew D. Livingston
Estimating the term…
An improved, high efficiency rotary drum dryer and method is disclosed which achieves outstanding thermal efficiencies by provision of a multiple-pass rotary dryer designed so that the product to be dried is first conveyed through an outermost drum of relatively large cross-sectional area and then through succeeding internal drums of progressively smaller cross-sectional areas. In this way, the velocity of induced air currents traveling through the dryer increases from pass to pass, with the result that the net velocity of product through successive passes also increases. The preferred dryer also includes housing structure in surrounding relationship to the innermost drum permitting introduction of relatively low humidity ambient-derived air into the central drum so as to lower the partial pressure of moisture in the drying atmosphere, thus promoting the final stage of drying. The preferred dryer also includes an assembly for selective introduction of a liquid or solid product treating agent into the final central drum. The dryer of the invention is capable of drying a greater volume of material with a shorter dryer and increased efficiencies are obtained because of increased airflow without attendant settling out of larger particles and possible dryer plugging.
A multiple-pass product treating device comprising:
A multiple-pass dryer, comprising:
In a method of drying an initially wet product in a multiple-pass rotary drum dryer, said dryer presenting structure defining a plurality of elongated, internal passageways each having an entrance end and an exit end and having respective, generally parallel and horizontal longitudinal axes, said passageways being intercommunicated with each other to present a continuous, serpentine flow path, and wherein the product is introduced in particulate form into said flow path and conveyed therealong by induced hot air currents, the improvement which comprises directing said air currents and product particles first to a radially outboard passageway and thence to radially inboard passageway(s), and, during traversal of said particles and air currents along said flow path, increasing the average net velocity of both said air currents and particles of said product in each of said elongated passageways as said particles and air currents pass along said serpentine flow path.
Dependencies are inferred from the claim text.