Abstract: An extruder for processing wood particles, shavings or sawdust is particularly useful for the production of a refined product exhibiting a large number of separated, individual fibers each of a relatively long length as is desirable in the production of a fiber core for a composite particle board. The extrusion apparatus comprises an elongated barrel and a flighted screw rotatable within the barrel, with the final downstream section of the screw being of a configuration to sequentially present three processing zones each having a compression region, a restricted region and a decompression region. The three processing zones of the final screw section cooperate with a compression region and restricted region formed in the final head section to choke the advancement of wood materials through the extruder sufficiently to enable satisfactory processing of the same without the use of a final die or restricted orifice disposed on the outlet of the extruder barrel.

Abstract: A greatly improved twin screw extruder and method are disclosed which significantly reduce extruder wear through provision of separate, complemental, interfitted frustoconical screw and barrel sections adjacent the outlet end of the extruder barrel which create an even, bearing-type support for the rotating screws as material passes through the apparatus. In preferred forms, the screws are intermeshed along the majority of the extruder barrel, but diverge at the region of the final frustoconical screw sections and are received within respective complemental barrel sections; in this fashion the material being processed is split into juxtaposed, non-communicating streams, and thereby evenly flows around and supports the adjacent screw section to lessen the tendency of the screws to separate themselves and come into wearing contact with the surrounding barrel walls. The extruder can be used to process a wide variety of plant-derived materials, but is particularly useful for viscous substances (e.g.

Abstract: A twin screw extruder which significantly reduces extruder wear through provision of separate, complemental, interfitted frustoconical screw and barrel sections adjacent the outlet end of the extruder barrel which create an even, bearing-type support for the rotating screws as material passes through the apparatus. In preferred forms, the screws are intermeshed along the majority of the extruder barrel, but diverge at the region of the final frustoconical screw sections and are received within respective complemental barrel sections; in this fashion the material being processed is split into juxtaposed, non-communicating streams, and thereby evenly flows around and supports the adjacent screw section to lessen the tendency of the screws to separate themselves and come into wearing contact with the surrounding barrel walls. The extruder can be used to process a wide variety of plant-derived materials, but is particularly useful for viscous substances (e.g.

Abstract: Quick cooking rice products are manufactured in a low mechanical shear extrusion process by first pre-cooking a rice and water mixture in a preconditioner and then advancing the mixture along the length of an extruder sequentially presenting a cooking zone, a venting zone, a forming zone, and finally an extrusion die to yield an extruded product. Venting of gaseous products removes a significant amount of moisture from the mixture during the time that the latter passes between the cooking zone and the forming zone, and consequently the moisture content of the mixture within the cooking zone can be increased in order to reduce the total mechanical shear imposed on the mixture during the cooking process. The extruded product, once dried, closely resembles rice grain and readily rehydrates without exhibiting slimy or sticky characteristics, and has an increased tolerance to overcooking.

Abstract: Quick cooking pasta products are extruded in a low temperature process by advancing a partially pre-cooked mixture of pasta flour and water prepared in a preconditioner along the length of a screw extruder through a cooking zone, then through a venting zone and a forming zone, and finally through an extrusion die to yield an extruded product. The mixture has a maximum temperature of 215.degree. F. in the cooking zone in order to substantially eliminate the formation of darkened specks in the final extruded product which would otherwise represent portions of the mixture that are burned during cooking. Limiting the maximum temperature of the mixture in the extruder also greatly enhances the extruded pasta quality by increasing product resistance to overcooking and improving the retention characteristics of the original product integrity.

Abstract: A conditioning device for an extruder includes two juxtaposed, frustocylindrical, intercommunicated chambers, one chamber of which has a greater cross sectional area than the other chamber. A mixing shaft centrally located within the small chamber carries a number of radially extending beaters which rotate at a speed twice that of the rotational speed of paddles mounted on a second mixing shaft located in the large chamber and material introduced into the vessel is passed from side-to-side between the two chambers while being advanced along the length of the vessel. The use of relatively fast moving beaters within a small mixing chamber in combination with relatively slow moving paddles in a larger mixing chamber enables flour-like materials to be properly blended with water with both sufficient agitation and proper retention times within the vessel.

Abstract: An improved, low cost, energy efficient extrusion device and method for processing of cellulose, hemicellulose, and like fiber-bearing materials is described which includes a pretreatment extrusion zone and a reaction extrusion zone separated by a pressure sensitive variable die. The method hereof includes the steps of extruding cellulosic material through the pretreatment zone at an elevated pressure and temperature, passing the material into the reaction zone where it is mixed with an acid and is processed at a lower pressure and temperature than in the pretreatment zone, and extruding the material through a final extrusion die. The surging and blowing usually experienced with extrusion of fibrous material is drastically reduced by the unique construction of the extruder die members. The cellulosic material may be hydrolyzed to simple sugars in accordance with the method and apparatus hereof with a minimum of acid degradation of the extrusion equipment.

Abstract: An improved, low cost, energy efficient extrusion device and method for processing of cellulose- or fiber-bearing materials (e.g., wood chips, crop residues, whole or ground soybeans) is described which includes a transition screw section designed to smooth out material flow through the extruder and allow creation of increased barrel pressure and temperature levels. The transition section includes first and second alternating flights, with the depth of the first flight being less than that of the second flight and preferably gradually increasing until it equals the second flight depth. The overall extruder apparatus also advantageously includes a single flighted inlet screw section and a double flighted compression screw section respectively disposed on opposite sides of the transition section; in addition, the extruder has a pressure responsive adjustable die so that the effective dimensions of the die opening can be varied during the extrusion operation.