Twin extruder

Details Twin extruder Twin extruder

1999-01-07

2001-01-30

Soohoo, Tony G. (Department: 1723)

Agitating

Rubber or heavy plastic working

With specified discharge means

C366S083000, C366S088000, C425S204000, C425S202000

Reexamination Certificate

active

06179459

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a twin extruder, and more specifically to a twin extruder where an underwater cutting apparatus is connected, via a gear pump, to a side portion or a lower portion of a cylinder which houses therein twin screws whose both ends are supported.
2. Related Art
This kind of twin extruder conventionally used is composed as shown in FIG.
3
. In the same, reference numeral
21
designates a cylinder in which a pair of first screw
22
and second screw
23
are disposed. Both screws
22
,
23
are sealed at both ends thereof with sealing members
24
,
24
a
, and supported by not shown bearings.
Both screws
22
,
23
are composed of a material supplying section
25
having a flight of small lead and a kneading section
26
having a flight of large lead. The flights of both screws
22
,
23
are inverse helical screws with respect to each other. Both screws are rotation driven by a not shown motor outward or inward each other (in this case, the flight is the inverse helical lead with respect to the figure), when seeing the upper parts of the screws from a drive source.
The cylinder
21
is provided with a material supplying hopper
27
about the upper part thereof corresponding to the material supplying section
25
.
The cylinder
21
is provided with an discharge port
28
at the side or lower part thereof positioned at the downstream of the kneading section
26
. The discharge port
28
is provided in order with a gear pump
29
, a screen changer
30
, a die
31
and an underwater cutting apparatus
32
.
Explanation will be made to actuation of the above mentioned twin extruder.
Resin material charged into the cylinder
21
from the hoppers
27
is transferred to the material conveying section
25
and the kneading section
26
, and is molten and kneaded. The molten and kneaded resin is sent to a downstream gear pump
29
from the discharge port
28
, goes through the screen changer
30
, the die
31
an the underwater cutting apparatus
32
, and pelletized.
Since the prior art twin extruder is composed as mentioned above, there exist the following problems.
(
a
) Since the axes are sealed under pressure with sealing members at the side of the discharge port of the cylinder, secure sealing is difficult.
(
b
) Since thermal expansion should be absorbed at the discharge port, centering of the underwater cutting apparatus is difficult.
(
c
) With respect to the diameter of the screw, amounts to be processed are limited.
SUMMARY OF THE INVENTION
It is an object of the present invention to make easy sealing of the axes of the twin extruder having the cylinder housing therein twin screws whose both ends are supported, and the underwater cutting apparatus is connected to the side part or the lower part of the cylinder, make centering of the underwater cutting apparatus easy, and increase amounts to be processed with the screws of the same diameter.
The twin extruder of the present invention, in which an underwater cutting apparatus is connected, via a gear pump, to an discharge port of a cylinder housing therein twin screws both ends of which are supported, is characterized in that both sides of both screws are material conveying sections having flights of small lead, the downstream sides of the respective material conveying sections are kneading sections having flights of large lead, both kneading sections are connected about the center of the screws and the cylinder positioned at the center of the screws is provided with the discharge port.


REFERENCES:
patent: 3224739 (1965-12-01), Schuur
patent: 3577588 (1971-05-01), Chisholm
patent: 3667733 (1972-06-01), Fritsch
patent: 3746319 (1973-07-01), Blach
patent: 3764118 (1973-10-01), Matsuoka
patent: 4212543 (1980-07-01), Bersano
patent: 4707139 (1987-11-01), Valenzky et al.
patent: 5179521 (1993-01-01), Edge
patent: 5409366 (1995-04-01), Vincent
patent: 1937 547 (1969-07-01), None
patent: 2 003 593 (1970-01-01), None
patent: 28 34 043 (1978-08-01), None
patent: 557562 (1957-02-01), None
patent: 57-199638 (1982-12-01), None
patent: 4-156932 (1992-05-01), None

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