초록 ▼

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 b

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.

대표청구항 ▼

[ What is claimed is:] [1.] A foam extrusion line comprising an extruder, a die, shaping and calibration equipment downstream of the die, an immersion cooling pond through which the extrudate is diverted and guided after leaving the shaping and calibration equipment, a haul-off drawing the extrudate

[ What is claimed is:] [1.] A foam extrusion line comprising an extruder, a die, shaping and calibration equipment downstream of the die, an immersion cooling pond through which the extrudate is diverted and guided after leaving the shaping and calibration equipment, a haul-off drawing the extrudate from the pond, dancer roll means measuring the deflection of the extrudate exiting the shaping and calibration equipment, and means responsive to the measured deflection to control the haul-off wherein said haul-off is a vacuum belt engaging and gripping a surface of the extrudate.