Patent ID: 6866171

Claim:
A system for introducing an additive into a viscous medium comprising: a conduit having an inlet and an outlet; means for introducing a viscous medium into said conduit inlet; an injector having a nozzle with an axially extending bore therein, said nozzle having a nozzle passage with a nozzle outlet in fluid communication with said conduit and an inlet in fluid communication with said bore, a needle extending axially within said bore and having valve means associated therewith for controlling fluid communication of said bore with said inlet of said nozzle passage as a function of the axial position of said needle in said bore; a pressure regulator for controlling the pressure of an additive in said bore and the viscous medium in said conduit; actuating means for axially moving said needle in said bore in response to an electrical signal in a cyclical manner from a first position whereat said nozzle passage inlet is closed to a second position whereat said nozzle passage inlet is in fluid communication with said bore to a set degree, said movement from said first position to said second position occurring at a set frequency and at a set time for said second position whereby said additive is pulsed into said medium.