Owens Corning Fiberglas Technology, Inc.

Robert M Lincoln, Jr

Robert L Sadinski

Russell C Woodburn

Rodger D Lightle

An extrusion system utilizes single or tandem extruders and a mixer-cooler to extrude a foamable extrudate through a die in a sealable chamber. The foamable extrudate is shaped and calibrated within the chamber. The die is mounted on the end of a gel tube projecting through a gland seal in a fixed bulkhead forming the upstream end of the chamber. The gel tube and mixer-cooler are mounted on a movable carriage, movement of which may be used to adjust the die with respect to shaping and calibrating equipment inside the chamber. The mixer-cooler achieves a selected narrow range of uniform viscosity of the melt at the die depending on the size of the product and density. The chamber is preferably a vacuum chamber producing low density foams. The product exits the chamber to atmosphere on a continuous basis through a submerged orifice in a water baffle immersion seal. The mixer-cooler enables a large size low density product to be produced with uniform cellular structure without cell collapse or density gradients, as the product is subjected to the pressure and temperature transformations passing from the chamber to atmosphere through the water. The seal includes the submerged orifice with a free wheeling guiding system upstream of the orifice. Immediately ahead of the guiding system, the parameters of the foam extrudate are sensed to control the configuration of the orifice on a continuous basis. Before the extrudate passes into the water baffle seal it moves over a floating dancer roll, the position of which controls a haul-off such as a vacuum belt at the tail end of the system. This avoids pushing on the extrudate.

Sealable chamber extrusion apparatus with seal controls

A horizontal vacuum extrusion line includes a fixed bulkhead, a die inside the bulkhead, a telescoping vacuum chamber section and a fixed chamber section. A dam in the fixed section forms a pond for immersion cooling of the extrudate. A truss extends from the dam to the bulkhead supporting, shaping and calibration equipment and extends through the telescoping section. Fluid pressurizable seals at each end of the telescoping section are operable after the telescoping section is closed against the bulkhead and the telescoping and fixed sections are locked together. The telescoping section provide a more compact line and easier access to the complex equipment downstream of the die. The extrudate from the die passes down into the pond and then through an orifice in a hood projecting from the chamber into a lower level portion of the pond exposed to atmosphere. The hood also includes a tractor drive to push the extrudate through the underwater orifice. The hood and its contents are accessible through the atmospheric pond. A tractor haul-off and the tractor drive in the hood are the only extrudate drives between the calibration equipment and atmosphere. The higher level of the pond within the chamber downstream of the dam is controlled by a valve in turn controlling the output of a pump. The valve control senses the pond level and operates independently of the vacuum controls.

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North Canton, OH, United States of America

Robert M Lincoln, Jr