Apparatus for extruding flowable materials

An apparatus for extruding a highly viscous material onto a substrate, comprising:

• a housing defining an interior and an inlet opening to the interior at a first end of the housing for receiving material to be extruded and an outlet opening to the interior at a second end or the housing for exiting extruded material;
• a screw rotatably supported within said housing interior and extending between the first end of the housing and the second end of the housing for displacing and compressing the material within the housing;
• a nozzle arrangement including an extrusion die disposed at the second end of the housing defining a die opening through which material is extruded from the housing interior onto the substrate;
• hydraulically operated motor means connecting with the screw;
• means on the housing for heating said material to a desired temperature;
• a pressure sensor carried on the housing at the second end for generating a signal indicative of the pressure of the material at the second end;
• and
• a controller electrically connected to the hydraulically operated motor means and to the pressure sensor, for generating a control signal in response to the pressure signal and transmitting the control signal to the hydraulically operated motor means.