System and method for controlling continuous mixer with melt pump

Apparatus for continuously processing a thermoplastic resin, comprising:

• a mixer/melter forming at least one substantially cylindrical material working chamber having an entrance opening and an adjustable size exit opening, and including
• i) a mixing rotor extending into and supported for rotary movement in said working chamber, and
• ii) rotor drive means to rotate the mixing rotor to push a thermoplastic resin through said working chamber and outward through said exit opening;
• means to continuously feed thermoplastic resin at a controllable rate through said entrance opening and into said working chamber;
• a melt pump having an inlet directly connected to the exit opening of the mixer/melter to receive the thermoplastic resin therefrom, and an outlet,
• wherein the inlet of the melt pump and the exit opening of the mixer/melter form an interface, and the melt pump includes
• i) a moving surface, and
• ii) pump drive means to drive said moving surface to engage and pump the synthetic thermoplastic resin at a variable and controllable rate through the melt pump and through the outlet thereof;
• means connected to the mixer/melter to vary the size of the exit opening thereof and to vary the pressure of the thermoplastic resin at the interface between the mixer/melter and the melt pump;
• first signal generating means to generate a first input signal representing the amount of energy used by the mixer/melter to feed the thermoplastic resin therethrough;
• second signal generating means to generate a second input signal representing the amount of energy used to adjust the size of the adjustable exit opening of the mixer/melter;
• third signal generating means to generate a third input signal representing the pressure of the thermoplastic resin at the interface between the mixer/melter and the melt pump;
• and
• control means connected to the first, second, and third signal generating means to receive the first, second, and third input signal therefrom, to process said input signals to determine a desired energy level for the melt pump, and to generate an output signal and to transmit the output signal to the melt pump to adjust the energy used by the melt pump to said desired level.