Apparatus and method for dispensing fluid materials wherein the fluid is discharged from a nozzle at a rate controlled by a metering valve having a seat and a stem moveable with respect to the seat to modulate the flow. A servo-actuator connected in a feedback control loop is used to position the valve...http://www.google.ca/patents/US4842162?utm_source=gb-gplus-sharePatent US4842162 - Apparatus and method for dispensing fluid materials using position-dependent velocity feedback
