Apparatus for cooling a melt strip of thermoplastic synthetic resin and process
AssigneeReifenhauser GmbH & Co. Maschinenfabrik
InventorsWalter Kramer, Klemens Krumm, Hans D. Ott
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Abstract
An apparatus and method for cooling a melt strip from a wide-slot die includes a cooling roller driven at a predetermined angular velocity and juxtaposed with a corona-discharge electrode in the form of a rotation symmetrical rigid bar which is rotated about its axis at an angular velocity much greater than that of the cooling roller. The rotating corona-discharge electrode can be received in a nonrotatable insulating chamber having air inlets on a side opposite a slot-shaped outlet training ionized air onto the melt strip.
Claims19
An apparatus for the cooling of a melt strip, comprising:
- a cooling roller having a surface receiving a melt strip of thermoplastic synthetic resin to be cooled and rotatable about an axis;
- means forming a nonrotatable ionization chamber composed of electrically insulating material and enclosing an axis, said chamber having an air outlet slit extending parallel to said axes and opening toward said surface, and at least one air inlet communication with said chamber;
- an elongated metallic corona-discharge electrode in the form of a rigid bar extending parallel to said axes in said chamber, said bar being rotatable about said axis enclosed by said chamber and forming an axis of said bar,
- means for applying an electrical potential across said electrode and said roller whereby said roller forms a counter-electrode for electrostatically adhering said strip to said surface by an electrostatic field generated between said electrode and said counterelectrode;
- means for supporting said bar at opposite sides of said roller;
- and
- means for rotating said bar about said axis enclosed by said chamber during generation of said electrostatic field.
A method of electrostatically adhering a melt strip of thermoplastic synthetic resin to a surface of a cooling roller rotated at a given angular velocity, comprising the steps of:
- (a) feeding a melt strip of thermoplastic synthetic resin to a surface of a cooling roller rotated at a given angular velocity;
- (b) juxtaposing with said strip and said surface an elongated metallic corona-discharge electrode in the form of a rigid bar extending parallel to an axis of rotation of said roller, spacedly juxtaposed with said surface and supported on opposite sides of said roller;
- (c) applying an electric potential across said bar and said roller to constitute said roller as a counterelectrode and generate an electrostatic field adhering said strip to said surface;
- and
- (d) rotating said bar about an axis thereof with a first angular velocity which is a multiple of a second angular velocity of said roller and such that a product of a diameter of said bar and said first angular velocity is greater than a product of a diameter of said roller and said second angular velocity.
Dependencies are inferred from the claim text.