Internal bubble cooling control system and method
AssigneeAddex, Inc.
InventorRobert E. Cree
Life of this patent
Estimating the term…
Abstract
An internal bubble cooling air control system in a blown film apparatus has sensors arranged to increase response time and reduce interference, and includes a high speed valve for fast actuation of air flow from a controller in response to signals received from the sensors.
Claims18
In an extrusion system having a die for receiving molten plastic and for providing from the die a bubble that exits the die in molten form and that solidifies above a frost line, the system providing cooling air on the bubble as it exits the die, the system comprising:
- a plurality of acoustic bubble sensors each arranged to provide a sound pulse to a bubble and to sense the sound pulse after it bounces off the bubble, the bubble sensors for providing data to indicate a position of the bubble;
- and
- a controller responsive to data from the plurality of bubble sensors for controlling a flow of cooling air to the bubble, the controlling disregarding data from a sensor that is blocked so that the sensor cannot sense the sound pulse after it bounces off the bubble, and continuing to use data from at least one other bubble sensor to determine a position of the bubble.
In an extrusion system having a die for receiving molten plastic and for providing from the die a bubble that exits the die in molten form and solidifies above a frost line, the system blowing cooling air on the bubble below the frost line, a method comprising:
- receiving information about a position of the bubble from a plurality of bubble sensors located at a vertical position;
- controlling a flow of air to the bubble in response to data from the bubble sensors;
- and
- disregarding out-of-range data from a sensor and using data from a remaining sensor to control the flow of air.
Dependencies are inferred from the claim text.