Harrel Inc. of Norwalk, Conn., said its redesigned sheet roll stack is tailored to meet new safety standards, by quickly opening the nip opening between the rolls by a 4-inch gap within three seconds of tripping an emergency release.
The standard is B151.20, 1999, under the American National Standards Institute and the Society of the Plastics Industry Inc. Extruder maker Harrel of East Norwalk, Conn., said the new standard became mandatory on all new and rebuilt equipment after August 2001, and all existing equipment in the field after August 2002.
The company said the nip opening on the chill roll stack is the most dramatic change. Most roll stacks now in use can open to 1 or 1½ inches. Harrel said most roll stacks in the field will have to be replaced or completely rebuilt to comply with the standard.
Harrel said sometimes it is possible to salvage existing rolls that are in good condition, and build them into a new roll stack frame.
The three chill rolls account for at least 30 percent of the total cost of the roll stack, the company said.
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