Application of a method and use of an apparatus for introducing an additive in a flowing medium

摘要

Additives are metered and mixed with flowing medium, especially polymers in extrusion or injection molding, using pulsating high-pressure (e.g. 200 MPa) injectors with needle. Injectors are of precision design similar to those used for common rail fuel injection systems on internal combustion engines. Injectors can contain two channels to keep hydraulic operating fluid and heated polymer separate. Independent claims are also included for the following: (a) adjusting the flow and dispersion of an additive with a pulsating injector by changing the configuration of the outlet orifice (0.08-0.2 mm diameter), needle operation, pump and mixing chamber; (b) the use of a pulsating injector to introduce additives into a duct of appropriately variable cross-section in an extrusion plant; (c) metering and mixing of components using an injector with concentric hollow needles leading to a common orifice; and (d) the use of a hollow compound needle injector with an inclined outlet orifice in injection molding.