Process and apparatus for forming tubular thermoplastic film

Claim 2

A cooling cell, for containing cooling liquid, in combination with a mandrel over the surface of which a thin tubular body may slidably move in a direction parallel to the main axis thereof from an inlet end to an outlet end thereof which comprises an upstanding outer wall adapted to circumscribe said mandrel and spaced from the surface thereof; an upstanding inner wall within said outer wall adapted to circumscribe said mandrel and narrowly spaced from the surface thereof thereby forming an annulus immediately adjacent to and surrounding said mandrel wherein cooling liquid may move in turbulent flow over the outer surface of said tubular body; means for admitting cooling liquid to said cooling cell and to said annulus at the end thereof adjacent to the outlet end of said mandrel; and means for withdrawing cooling liquid from said annulus at the end thereof adjacent to the inlet end of said mandrel.

Claim 3

The cooling cell of claim 1 wherein: a. said means for admitting cooling liquid includes a laterally extending bottom wall joining said upstanding outer wall and terminating at an inner edge adjacent to said mandrel, and resilient seal means connected with the inner edge of said bottom wall and projecting therefrom toward said mandrel whereby said tubular body may pass between said mandrel and said seal means; and b. said means for withdrawing cooling liquid includes an upstanding outlet wall at said inlet end for said tubular body and circumscribing said mandrel at a distance further therefrom than the distance of said upstanding inner wall, and a laterally extending cover plate fitting over said upstanding outlet wall and terminating at a point closer to said mandrel than said upstanding inner wall; said cover plate, outlet wall, and said mandrel defining therebetween a quiescent zone.

Claim 4

The cooling cell of claim 2 wherein said outlet wall includes an upper port and a lower port; said lower port being adapted to allow a predetermined volume of cooling liquid to pass therethrough with the remaining liquid passing through said upper port.

Claim 5

A cooling cell for containing cooling liquid which comprises an annular body having: a. a laterally extending bottom wall terminating at an inner edge; b. resilient seal means connected with said inner edge and projecting inwardly therefrom; c. a first upstanding wall operably connected to said bottom wall; d. inlet means for admitting cooling liquid to said cooling cell and directing said liquid to the lower interior surface of said first upstanding wall; said inlet means including said bottom wall and said seal means; e. a second upstanding wall at least partially above and operably connected to said first upstanding wall and at a distance disposed outward of said first upstanding wall, both upstanding walls being considered in relation to the inner edge of said bottom wall; f. a laterally extending cover plate fitting over said second upstanding wall and terminating at a point inward of said first upstanding wall; said cover plate and said second upstanding wall defining and forming a top chamber; and g. outlet means for withdrawing cooling liquid from said top chamber and said cooling cell.

Claim 6

A cooling cell for containing cooling liquid which comprises an annular body having: a. a laterally extending bottom wall terminating at an inner edge; b. resilient seal means connected with said inner edge and projecting inwardly therefrom; c. a first upstanding wall operably connected to said bottom wall; d. inlet means for admitting cooling liquid to said cooling cell and directing said liquid to the lower interior surface of said first upstanding wall; said inlet means including said bottom wall and said seal means; e. a second upstanding wall at least partially above and operably connected to said first upstanding wall and at a distance disposed outward of said first upstanding wall, both upstanding walls being considered in relation to the inner edge of said bottom wall; f. a laterally extending cover plate fitting over said second upstanding wall and terminating at a point inward of said first upstanding wall; said cover plate and said second upstanding wall defining and forming a top chamber; and g. outlet means for withdrawing cooling liquid from said top chamber and said cooling cell.

Claim 7

The cooling cell of claim 4 wherein said outlet means comprises an upper port and a lower port, said ports being contained in said second upstanding wall, with said lower port being adapted to allow a predetermined volume of cooling liquid to pass therethrough, the remaining liquid passing through said upper port.