High stalk blown film extrusion apparatus and method
OwnerFrank D. Cerisanoinventor
Life of this patent
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Abstract
A high stalk blown film extrusion apparatus and method is described which produces a stabilized high stalk for increasing the production rate of blown, low to high molecular weight polymers, while increasing the film's physical and mechanical properties. The high stalk is stabilized by application of high velocity, low volume flow rate of air over the interior and exterior surfaces of the extruded film.
Claims47
An apparatus for forming a film of plastic material, said apparatus comprising supplying means for supplying plastic material in a flowable state, a die arranged in advance of said supplying means for forming a progressively advancing unexpanded tubular film having a substantially uniform first diameter along a longitudinal axis over a predetermined distance, a primary air ring arranged adjacent said die and exteriorly of said film, said primary air ring supplying a first gas stream over the exterior surface of said film, means for supplying a second gas stream over the interior surface of said film, a cylinder arranged interiorly of said film and extending from said die along said longitudinal axis over said predetermined distance, said cylinder and the interior surface of said film defining an annular region therebetween for receiving said second gas stream, controlling means for controlling said first and second gas streams over said unexpanded tubular film to stabilize said film over said predetermined distance by preventing the oscillation of said film about said cylinder, and a secondary air ring arranged spaced from said primary air ring and exteriorly of said film having said first diameter, the distance between said primary and said secondary air rings defining said predetermined distance over which said film is stabilized, said secondary air ring supplying a third gas stream over the exterior surface of said film for stabilizing and expanding said film from said first diameter to a second diameter thereat.
An apparatus for forming a film of plastic material, said apparatus comprising an extruder for supplying plastic material in a flowable state, a die arranged in advance of said extruder for forming a progressively advancing unexpanded tubular film having a substantially uniform first diameter along a longitudinal axis over a predetermined distance, a primary air ring arranged adjacent said die and exteriorly of said film, said primary air ring supplying a first gas stream over the exterior surface of said film, means for supplying a second gas stream over the interior surface of said film, a cylinder arranged interiorly of said film and extending from said die along said longitudinal axis over said predetermined distance, said cylinder and the interior surface of said film defining an annular region therebetween for receiving said second gas stream, controlling means for controlling said first and second gas streams over said unexpanded tubular film to stabilize said film over said predetermined distance, said controlling means controlling the velocity and volume flow rate of said first and second gas streams to prevent oscillation of said film about said cylinder by controlling said first gas stream at a sufficiently high velocity, low volume flow rate along the exterior surface of said film over said predetermined distance and by controlling said second gas stream at a sufficiently high velocity, low volume flow rate along the interior surface of said film within said annular region and over said predetermined distance, and a secondary air ring arranged spaced from said primary air ring and exteriorly of said film having said first diameter, the distance between said primary and said secondary air rings defining said predetermined distance over which said film is stabilized, said secondary air ring supplying a third gas stream over the exterior surface of said film for stabilizing and expanding said film from said first diameter to said second diameter thereat.
A method for forming a film of plastic material, said method comprising the steps of forming a progressively advancing unexpanded tubular film having a substantially uniform first diameter about a cylinder arranged along a longitudinal axis over a predetermined distance, applying a first gas stream over the exterior surface of said film, applying a second gas stream over the interior surface of said film within an annular region formed between said cylinder and the interior surface of said film, controlling the velocity and volume flow rate of said first and second gas stream over said unexpanded tubular film over said predetermined distance for stabilizing said film by preventing the oscillation of said film about said cylinder, and applying a third gas stream over the exterior surface of said film having said first diameter adjacent the extent of said predetermined distance for stabilizing and expanding said film from said first diameter to a second diameter thereat.
A method for forming a film of plastic material, said method comprising the steps of extruding a progressively advancing unexpanded tubular film having a substantially uniform first diameter about a cylinder arranged along a longitudinal axis over a predetermined distance, applying a first gas stream over the exterior surface of said film, applying a second gas stream over the interior surface of said film within an annular region formed between said cylinder and the interior surface of said film, controlling the velocity and volume flow rate of said first and second gas streams over said unexpanded tubular film over said predetermined distance for stabilizing said film, said stabilizing including applying said first gas stream at a sufficiently high velocity, low volume flow rate over the exterior surface of said film and said second gas stream at a sufficiently high velocity, low volume flow rate over the interior surface of said film to prevent the oscillation of said film about said cylinder, and applying a third gas stream over the exterior surface of said film having said first diameter adjacent the extent of said predetermined distance for stabilizing and expanding said film from said first diameter to a second diameter thereat.
The method of claim 42 wherein said stabilizing includes applying said first gas stream over the exterior surface of said film in a direction parallel thereto.
Dependencies are inferred from the claim text.