Plastic article or earthenware shaping or treating: apparatus – Traversing roll pressurizing means operably associated with...
Patent
1985-12-02
1988-09-13
Hoag, Willard E.
Plastic article or earthenware shaping or treating: apparatus
Traversing roll pressurizing means operably associated with...
425DIG230, B29C 4700
Patent
active
047706252
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to an apparatus and a method for extruding plastic or pulverulent materials prepared for the purpose of obtaining an extrudate in the form of rod shaped bodies.
The object of the present invention is to obtain a possibility to extrude plastic or pulverulent materials prepared for the purpose (semimoist) (15-45% by weight of water) to the formation of an extrudate without using any substantial compressing or pressure forces in the materials which forces increase the temperature while extruding. The extrudate obtained can be used as such, or be further treated.
BACKGROUND OF THE INVENTION
It is previously known apparatuses for extruding plastic deformable or pulverulent materials (semimoist) which have been prepared for the purpose for the production of extrudates of different kinds, such as raw materials, or end products for the pharmaceutical, food, or feed-stuff industries, as well as for the production of fertilizers and other organic and inorganic products.
Hitherto known apparatuses having been used for extrusion said materials are to be compared with meat mincing-machines, where the material by means of one or more screws is fed and pressed up to and through an aperture disc, which can be axially or radially arranged. Already the physical action of the screws makes this method irrational and provides for shearing forces in the material with accompanying heating effects, which in most cases are destructive. Furthermore, the material is graded into a solid/liquid phase prior to the aperture disc, which results in an inhomogenous product. The pressure force needed according to this method is further applied onto the whole area of the aperture disc, which after a short time leads to a deformation of the aperture disc. This deformation is particularly annoying at aperture diameters of 1 mm and less, when the screen (aperture disc) by deformation goes away from the screw(-s) and the forming effect of these, which means that the load has to be further increased.
The disadvantage of this known technique for extruding plastic deformable or pulverulent materials prepared for the purpose is as mentioned above that too high a temperature is built up during too long a period which in many cases means a destruction, or at least a serious risk for destruction of the material fed, particularly when organic material is present. Also inorganic materials can, however, change, e.g., by release of chemically bound water, which can completely change the chemical and physical properties of the product at hand.
Demands have thus been brought forward requesting a device and a process which provides for the production of an extrudate of heat- and pressure sensitive materials for obtaining well formulated extrudates by extrusion, while avoiding temperature increasing compression and pressure forces during a substantial time period, within the material.
DESCRIPTION OF THE PRESENT INVENTION
It has now surprisingly been shown possible to be able to produce extrudates by extrusion by means of the present invention, which is characterized by an annular perforated screen, a rotor being rotably arranged on the inside of said perforated screen, which rotor is provided with a number of compression surfaces working in close rotation to said perforated screen, which surfaces are arranged with an acute angle with the perforated screen in their rotational direction.
Further characteristics are apparent from the accompanying claims.
By means of the present invention plastic materials or pulverulent materials having been prepared for the purpose, which are fed into the rotor, will be compressed during a very short period of time at the very utmost ends of compression surfaces towards the perforated screen, only, and be pressed through the perforated screen by means of the stopping up effect. The compression forces on the perforated screen will thereby be located along the lines where the compression surfaces touch the perforated screen. The force on the perforated screen is thus, totally, o
REFERENCES:
patent: 2144054 (1939-01-01), Hall
patent: 2160302 (1939-05-01), Billows
patent: 2295743 (1942-09-01), Meakin
patent: 3166026 (1965-01-01), Crane
patent: 3511190 (1970-05-01), Kunz
patent: 3758563 (1973-09-01), Uematsu et al.
Appelgren Curt H.
Ivarsson Nemo
Hoag Willard E.
Lejus Medical Aktiebolag
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