“What that really means is that we have developed an innovative processing tool that couples a back-pressure valve with an external density chamber,” said Bob Hauck, Wenger's director of extrusion technology. The company's External Density Management System allows customers to increase capacity over vented configurations by as much as 25 percent to 50 percent, he said, adding that the system also allows processors to make both floating and sinking aquatic feeds with a range of properties without the need for extruder configuration changes.
One method of controlling a product's final characteristics is to adjust a system's extruder die restriction. The Wenger system, though, has a back-pressure valve that allows die-restriction adjustment while the extrusion system is in operation. This variable-opening valve, mounted on the end of the extruder just prior to the final die, means the operator can adjust specific mechanical energy and extrusion pressure online to control specific product properties, including bulk density, shape definition, cell-structure size and uniformity, and water and fat absorption. A bypass feature in the back-pressure valve allows the processor to divert off-spec product prior to final processing.
For more information contact Doug Baldwin at (816) 892-9272 or visit www.wenger.com.