ACCURATE MEASUREMENT OF EXTRUDATE TEMPERATURE AND HEAT-LOSS ON A TWIN-SCREW EXTRUDER

Infrared (IR), extended melt and flush thermocouple probes were used t o measure bulk temperatures of extrudates. Good agreement was obtained between IR and extended probes. However, substantial differences were observed between IR and flush mounted probes and between extended and flush mounted probes. A response surface methodology was used to stud y effects of moisture screw speed, and barrel temperature on measured temperature differences between IR and flush probes. The standard flus h probe may not accurately measure bulk temperature of the extrudate. The heat flux from the surfaces (top, bottom, and side) of a twin-scre w extruder barrel was also measured. Total heat loss from the surface varied between 2-19% of the total heat input.