Plastic article or earthenware shaping or treating: apparatus – Control means responsive to or actuated by means sensing or... – Feed control of material en route to shaping area
Patent
1996-07-02
1998-08-04
Ryan, Patrick
Plastic article or earthenware shaping or treating: apparatus
Control means responsive to or actuated by means sensing or...
Feed control of material en route to shaping area
425381, 4253824, 425466, B29C 4722
Patent
active
057889988
DESCRIPTION:
BRIEF SUMMARY
The invention relates to an adjustable throttle having a flat flow channel with a width to height ratio or a circumference to height ratio, respectively, of at least 10 for the guidance of a mass flow of free flowing material, comprising an inlet portion and an outlet portion and a central flow channel portion interconnecting these two channel portions, the flow channel being free from parting planes and free from dead spots throughout the flow channel portion between the flow channel inlet and the flow channel outlet, and its channel height being modifiable, in the central flow channel portion, from the outside by way of adjusting means by elastic deformation of the wall of at least one wall portion by more than 0.1 mm.
BACKGROUND ART
An adjustable throttle of the generic type mentioned above is known from U.S. Pat. No. 3,884,611. In this throttle, the flow channel is plane. A recess is formed in a thick-walled limiting wall of the flow channel in such a way that a thin wall portion is formed. This wall portion, which is equally flat, i.e. plane, in its position of rest, can be deformed in a direction right into the flow channel by screws as adjusting means, i.e. it can be curved slightly, which renders possible an adjustment of the channel height. On the one hand, the possibilities of making an influence on the channel height are limited, since the thin wall portion is elongated, which is possible only to a limited extent. Moreover, after numerous adjusting operations, the material of this thin wall portion will deform plastically, no longer returning elastically into its initial position.
U.S. Pat. No. 3,122,789 teaches an extrusion die which has a straight flow channel. A wall of this flow channel can be deformed by hydraulic pressure for the width of the opening of the slit die to be changed at its outlet portion. Apart from the fact that throttling does not take place in a central flow channel portion between an inlet portion and an outlet portion, the adjusting problems are the same as mentioned above.
OBJECT AND SOLUTION
It is the object of the invention to develop a metal throttle that is adjustable with great sensitivity and by means of which, over the width of the flow channel, a mass flow that passes through can be modified. Further, it is the object of the invention to produce coextruded sheets of a constancy of layer thickness not achievable so far by the use of the apparatus according to the invention.
According to the invention, this object is solved in that the flow channel has a curvature and in that the elastically deformable wall defines the flow channel in the vicinity of the latter's curvature.
Further, it is advantageous if flow channel portions of non modifiable geometry are located before and behind the flow channel portion.
In keeping with another advantageous embodiment, the adjusting range of the adjusting member is at least 0.1 mm.
According to another advantageous embodiment, provision is made, in the vicinity of the adjusting members, for the flow channel to have portions of a channel height H, to which applies: H<5 mm.
It is especially advantageous if the wall, where elastically deformable, has a wall thickness A, to which applies: A<6 mm and preferably 0.5 mm<A<4 mm.
In keeping with yet another advantageous embodiment, the distance of the adjusting members from each other is less than 15 mm.
It is further of advantage if the flow channel is treatable and located in an extrusion die.
According to another advantageous embodiment, the flow channel is located in a coextrusion adapter.
Finally, it is of advantage if the elastically deformable wall defines the flow channel on the latter's outside in the vicinity of the latter's curvature.
The object of the invention is attained by a construction as seen diagrammatically in FIG. 1. The width to height ratio of the flow channel should exceed 10, however preferably amount to 20 to 5000. The adjusting range of the adjusting members 5 should be at least 0.1 mm, preferably 1-1.5 mm, for sufficient modification of the
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patent: 5466402 (1995-11-01), Lupke
Ryan Patrick
Schwartz Iurie A.
LandOfFree
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