Agitating – Rubber or heavy plastic working – With specified vent means
Reexamination Certificate
2000-07-11
2002-07-23
Soohoo, Tony G. (Department: 1723)
Agitating
Rubber or heavy plastic working
With specified vent means
C425S203000, C425S812000, C425S204000, C425SDIG001
Reexamination Certificate
active
06422732
ABSTRACT:
BACKGROUND
The present invention relates to a device for extracting undesired substances, such as volatile components of low molecular weight, free gases, liquids and the like from the cylinder of an extruder, in particular for the processing of thermoplastic materials. These substances develop in the extruder during mixing and stabilization processes and during other processes involving chemical reactions.
SUMMARY OF THE INVENTION
In more detail, the extractor device includes:
a casing defining internally an oblong cavity communicating at one end with the inner cavity of the cylinder of the extruder,
at least one screw mounted for rotation inside the said oblong cavity, substantially parallel to the longitudinal axis thereof, and
vacuum means operable to cause a depression in the said oblong cavity.
In a technique known in the prior art, such a device is mounted in such a way that the longitudinal axis of the oblong cavity lies substantially vertically over the extruder, with the axis of the cylinder thereof lying substantially horizontally.
In operation, undesired substances are extracted through the casing by vacuum means, while the thermoplastic material is retained in the extruder by rotation of the screws.
Meanwhile, the undesired extracted substances tend to condense and to fall, due to the force of gravity and to the vertical arrangement of the casing, back into the extruder, thus contaminating the thermoplastic material being processed.
In order to overcome such drawback, the subject matter of the present invention is a device of the type described at the start of this description, wherein the longitudinal axis of the oblong cavity forms an angle of between 0° and −45°, preferably of between 0° and −15°, with a horizontal plane passing through the axis of the cylinder of the extruder.
According to the invention, the horizontal or downward inclination of the axis of the oblong casing prevents the condensed undesired substances from falling back into the extruder, but retains them in the extractor device. At the same time, rotation of the screws is sufficient to keep the thermoplastic material being processed in the extruder. In this way, undesired substances are efficiently separated from the thermoplastic material without any undue effect on the processing thereof.
According to requirements, the cavity of the device of the invention can be designed to accommodate a single rotatable screw or two or more interpenetrating rotatable screws.
An additional object of the present invention is constituted by an extruder, e.g. of a single screw or twin screw type, associated with an extractor device of the type just described.
Further characteristics and advantages of the present invention will become apparent from the detailed description which follows, given with reference to the appended drawings, provided purely by way of non-limitative example, in which:
REFERENCES:
patent: 3535737 (1970-10-01), Hendry
patent: 3563514 (1971-02-01), Shattuck
patent: 3572647 (1971-03-01), Staheli
patent: 3917507 (1975-11-01), Skidmore
patent: 3985348 (1976-10-01), Skidmore
patent: 4110843 (1978-08-01), Skidmore
patent: 4130901 (1978-12-01), Borovikova et al.
patent: 4260264 (1981-04-01), Maki et al.
patent: 4474473 (1984-10-01), Higuchi et al.
patent: 4752135 (1988-06-01), Loomans
patent: 4763569 (1988-08-01), Wenger et al.
patent: 4776784 (1988-10-01), Batiuk
patent: 4846054 (1989-07-01), Mange et al.
patent: 5030080 (1991-07-01), Fukuda et al.
patent: 5297864 (1994-03-01), Knoll et al.
patent: 5626420 (1997-05-01), Deal et al.
patent: 5662415 (1997-09-01), Gisko
patent: 6030203 (2000-02-01), Kuroda
patent: 6068466 (2000-05-01), Morita
F. LLI Maris S.p.A.
Myers Bigel & Sibley & Sajovec
Soohoo Tony G.
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