Plastic article or earthenware shaping or treating: apparatus – With upstream screen or perforated plate for straining,... – Upstream of multi-orifice shaping die
Reexamination Certificate
2001-05-11
2004-09-14
Davis, Robert (Department: 1722)
Plastic article or earthenware shaping or treating: apparatus
With upstream screen or perforated plate for straining,...
Upstream of multi-orifice shaping die
C425S199000, C425S204000, C425S205000, C425S208000, C425S380000, C366S082000, C366S088000, C366S089000
Reexamination Certificate
active
06790025
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an extrusion molding apparatus for molding a ceramic molded product such as a ceramic honeycomb structure.
2. Description of the Related Art
As shown in
FIG. 9
described later, a ceramic honeycomb structure
8
having a plurality of cells
88
with partitioning walls
81
is used, for example, as a catalyst carrier in an exhaust gas purification system of an automotive vehicle. This honeycomb structure
8
is normally fabricated by extrusion molding.
A conventional extrusion molding apparatus
9
for a honeycomb structure, as shown in
FIG. 10
, for example, comprises a mold
11
for molding the honeycomb structure
8
, and screw extruders
92
,
93
in two stages, upper and lower, for kneading and extruding a ceramic material
80
continuously.
As shown in
FIG. 10
, the screw extruders
92
,
93
include screws
94
,
95
built in housings
929
,
939
respectively. By rotating the screws
94
,
95
, the ceramic material
80
introduced into the housings
929
,
939
is extruded by way of an extrusion port at the forward end thereof. The screws
94
,
95
include pressure portions
41
,
51
formed by spirally winding lead portions
410
,
510
, and kneading portions
42
,
52
having a plurality of disk-shaped flange portions
420
,
520
, respectively, arranged in spaced relation along the axial direction. Conical forward end portions
945
,
955
are arranged on the side of the kneading portions
42
,
52
nearer to the forward end extrusion port.
The forward end extrusion ports of screw extruders
92
,
93
have filters
62
,
63
, respectively. A mold
11
is arranged on the forward end port side of the lower screw extruder
93
through a resistance tube
12
. The ceramic material
80
is extruded and molded as a honeycomb structure
8
from the mold
11
.
The screw extruder may be arranged in a single stage or in three or more stages.
The conventional extrusion molding apparatus
9
described above poses the following problem.
Specifically, the rate at which the ceramic material
80
is extruded from each screw extruder
92
,
93
is reflected in the rate at which a ceramic molded product, such as a honeycomb structure
8
, is extruded. The higher the extrusion rate of the screw extender, the more efficiently the ceramic molded product can be fabricated.
The extrusion rate of the screw extruders
92
,
93
can be increased by increasing the rotational speed of the screws
94
,
95
. To accomplish this, however, a considerable reconstruction of the equipment drive system is required and cannot be realized readily.
In view of this, development of a technique has been desired for increasing the extrusion rate of the screw extruder efficiently without substantially reconstructing the drive system.
SUMMARY OF THE INVENTION
The present invention has been achieved in view of the problem mentioned above, and the object thereof is to provide an extrusion molding apparatus which can increase the rate at which a ceramic material is extruded, without substantial reconstruction of the drive system.
REFERENCES:
patent: 3685804 (1972-08-01), Stansfield
patent: 4136969 (1979-01-01), Meyer
patent: 4729666 (1988-03-01), Takubo
patent: 4839120 (1989-06-01), Baba et al.
patent: 5055027 (1991-10-01), Sato
patent: 5064586 (1991-11-01), Higashijima
patent: 5980227 (1999-11-01), Murata et al.
Katou Hiromi
Miura Yasunao
Yamaguchi Satoru
Davis Robert
Del Sole Joseph S.
Denso Corporation
Harness Dickey & Pierce PLC
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