Plastic article or earthenware shaping or treating: apparatus – Means feeding fluent stock from plural sources to common... – Extrusion shaping means
Reexamination Certificate
1998-08-28
2001-10-02
Nguyen, Nam (Department: 1722)
Plastic article or earthenware shaping or treating: apparatus
Means feeding fluent stock from plural sources to common...
Extrusion shaping means
C425S311000, C425S381000, C425S382400, C425S464000, C425S466000, C425S467000
Reexamination Certificate
active
06296465
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to extrusion of substances, particularly food products, and particularly to dies for extrusion of such substances to obtain shaped products, and more particularly to die structures for extruding a plurality of extrudate streams to obtain products.
European Patent Application Publication No. 0 169 126 (CLEXTRAL) describes a method and installation for manufacturing a composite food product from a single-screw or double-screw extrusion cooker, in which a stream of material is processed in a first conventional processing zone of the extrusion cooker, and then divided in two streams in a second zone comprising two separate parallel processing chambers, the two streams are processed by being, in particular, colored differently in their respective processing chambers, and the streams are combined during their extrusion through a die having a single outlet orifice or a coextrusion die.
SUMMARY OF THE INVENTION
The object of the present invention is to provide an extrusion die making it possible, by extruding a unitary material, to produce a product which has an especially attractive three-dimensional shape, namely, the general shape of a core surrounded by a ring.
For this purpose, the extrusion die according to the present invention comprises a feed diaphragm opening into a distribution chamber communicating, on one hand, with a generally conical convergent central extrusion duct by means of a circular central pre-expansion and/or retarding diaphragm and communicating, on the other hand, with at least one generally conical convergent coaxial tubular extrusion duct by means of at least one annular pre-expansion and/or retarding diaphragm, the central and coaxial tubular extrusion ducts having respective concentric central and annular outlet orifices.
The extruder according to the present invention comprises an elongate sleeve, containing one or two processing screws, and at least one such extrusion die.
Finally, the product according to the present invention, capable of being obtained by extrusion through such a die, has the general shape of a core surrounded by a ring.
DETAILED DESCRIPTION OF THE INVENTION
In this description, the term “diaphragm” means a pipe element, the diameter of which narrows to an orifice of reduced aperture and which may, in particular, take the form of an insert, in which an orifice is provided, to which a generally conical upstream wall converges and from which a generally conical downstream wall diverges.
The expression “pre-expansion and/or retarding” means preliminary expansion and/or retarding of a mass of material processed in an extruder, which takes place at an intermediate stage prior to emergence from the extrusion die. Such pre-expansion and/or retarding may be caused by the passage of the mass through a diaphragm opening into a pre-expansion and/or retarding space or chamber, defined by a divergent wall, as mentioned above, or onto an even wider space provided, for example, immediately downstream of the diaphragm.
The expression “concentric central and annular outlet orifices” means a central outlet orifice, which is located in a plane generally perpendicular to the axis of the die and centered on this axis, and at least one annular orifice, likewise located in a plane generally perpendicular to the axis of the die and also centered on this axis. These orifices may have various shapes, such as a circle, oval, ellipse, heart, triangle, figure of eight, flower petals Or their combinations, such as, for example, a daisy with a circular central orifice and a petal-shaped annular orifice.
The expression “processing screw” means the extruder screw or screws which are driven in rotation within a bore, or two secant bores provided in the sleeve and to which are fastened processing members, such as threads wound helically about their axis. The configuration, pitch, depth and direction of such threads may be provided in various ways along the axis to define various processing zones, such as, for example, transport, moistening, mixing, shearing, compression and/or cooking zones. Such screws may be produced, for example, in one piece or by assembling elements slipped successively onto a shaft.
In a preferred embodiment of the present die comprising a coaxial tubular extrusion duct, the aperture of the pre-expansion and/or retarding diaphragms and/or of the outlet orifices and/or the distance between the planes of the outlet orifices can be adjusted in such a way so that simultaneously cutting off a central strand emerging from the central outlet orifice and a coaxial tubular strand emerging from a concentric annular outlet orifice produces a core surrounded by a ring integral with the periphery of the latter.
In another preferred embodiment of the die comprising a plurality of coaxial tubular extrusion ducts, the aperture of the pre-expansion and/or retarding diaphragms and/or of the outlet orifices and/or the distance between the planes of the outlet orifices can be adjusted in such a way that simultaneously cutting off a central strand emerging from the central outlet orifice and a plurality of coaxial tubular strands emerging from a plurality of concentric annular outlet orifices produces a core surrounded by a plurality of concentric rings integral with the latter at intervals.
The adjustability of the apertures and distances may also make it possible to influence the texture of the product, in particular, for example, the degree of expansion of a cooked and extruded product.
It may be assumed that a suitable adjustment of the apertures and distances, which makes it possible to produce a core surrounded by a ring integral with the periphery of the latter or a core surrounded by a plurality of concentric rings integral with the latter at intervals, is an adjustment which, for example, imparts appreciably different respective speeds to the strands emerging from the central orifice and from the concentric annular orifice.
In the present die, for example, the central extrusion duct may be delimited by the inner wall of an inner nozzle and a coaxial tubular extrusion duct may be delimited by the inner wall of an outer nozzle and by the outer wall of an inner nozzle.
The central outlet orifice may be delimited by the end of an inner nozzle and an annular outlet orifice may be delimited by the ends of inner and outer nozzles.
The aperture of the pre-expansion and/or retarding diaphragms may be adjustable by the substitution of inserts in which these diaphragms are formed.
The aperture of the outlet orifices may be adjustable by the substitution of inner and outer nozzles.
Finally, the distance between the planes of the outlet orifices may be adjustable by the relative axial displacement of inner and outer nozzles.
The extruder apparatus according to the present invention comprises an elongate sleeve, containing one or two processing screws, and at least one extrusion die according to the present invention, and it preferably comprises furthermore, cutting-off means which may, for example, take the form of a rotary knife rotating against the outlet orifices.
In a preferred embodiment of the extruder comprising a plurality of dies, a downstream part of the sleeve, which contains a downstream end of the processing screw or screws, terminates in a front plate which is integral with the sleeve and is provided with a pre-distribution orifice into which opens a pre-distribution chamber communicating with the distribution chambers of the dies by means of the feed diaphragms.
The pre-distribution orifice may open onto the pre-distribution chamber by means of a pre-distribution diaphragm which, for example, may be adjustable by the substitution of the insert in which it is formed.
Preferably, the product obtained by extrusion in accordance with the present invention is intended as human or animal food and suitably is processed by the processing screws of an extruder which supply the mechanical energy necessary to cause the material to pass through the die.
Various particular embodiments of the present product may
Deutsch Roman
Heck Ernst
Horisberger Jean
Del Sole Joseph S
Nestec S.A.
Nguyen Nam
Winston & Strawn
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