Apparatus for preparing and dispensing thermoplastic resin

Apparatus for preparing and intermittently dispensing thermoplastic resin, comprising:

• an extruder;
• said extruder having;
• a chamber;
• heating means associated with said chamber;
• an extruder screw mounted for rotation within said chamber;
• drive means for effecting the rotation of said extruder screw;
• an inlet for the supply of said resin to said chamber;
• an outlet for dispensing said resin in a liquid condition;
• control means connected to said drive means for controlling the speed of rotation of said extruder screw to thereby control the dispensing of said resin from said outlet;
• pressure measurement means intermediate said inlet and outlet for measuring the pressure within said chamber of said extruder and providing a first input signal to said control means;
• means for measuring the amount dispensed per unit time of thermoplastic resin and providing a second input signal to said control means;
• means for providing a third input signal to said control means corresponding to a predetermined value of said pressure;
• means for providing a fourth input signal to said control means corresponding to a predetermined value of said amount of thermoplastic resin to be dispensed per unit of time;
• and
• said control means providing a first output signal to said drive means to control said drive means and the rotation of said extruder screw during dispensing of the resin, said first output signal controlling rotation of said extruder screw to maintain the amount of resin dispensed per unit time at said predetermined value, said control means providing a second output signal to said drive means during intermittent interruption of the dispensing of the resin, to control rotation of said extruder screw maintaining the pressure of the resin within said chamber at a predetermined value.