Continuous in-line melt flow rate control system

The continuous in-line melt flow rate control system (40; 100) is coupled to a mixer/extruder system (10; 97) including a polymer, stabilizer and degradent feeding system (12, 16, 18; 102) supplying mixed materials to the inlet end of an extruder (24; 108) having a die head (26) at the outlet end thereof. The control system (40; 100) is coupled between a rheometer (42; 112) which monitors a slip stream (46; 110) of melt from the extruder (24; 108) and a ratio controller (48; 93) in the feeding system (12, 16, 18; 102). The control system (40; 100) includes a rheometer (42; 112) which monitors the viscosity of the slip stream of melt from the extruder (24; 108) upstream from the die head (26) and converts the monitored viscosity value to a process signal (F) and a controller (44; 84; 101) that compares the process signal (F) with a set point value (A) related to a target melt flow rate and generates a correction signal (B, C, D) when there is a difference between the process signal (F) and the set point value (A). The correction signal (D) is supplied to the degradent ratio controller (48; 93) for adjusting the amount of degradent added to the polymer fed to the extruder (24; 108) in response to the deviation of the process signal (F) from the set point value (A).