Dynamic mixing system and method for producing thermoplastic materials
OwnerThomas W. Winsteadinventor
Life of this patent
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Abstract
A dynamic mixing system and method intensively mixes thermoplastic melt with other ingredients and entrains gas as a blowing agent in a thermoplastic melt so as to provide a foamed thermoplastic extrudate. The dynamic mixing system includes a plurality of mixing balls disposed circumferentially about the surface of a cylindrically shaped spindle which is rotatably disposed within a barrel, such that upon rotation of the spindle the mixing balls rotate in a planetary manner so as to intensively mix a flow of thermoplastic melt, for example, to entrain a blowing agent in the melt.
Claims42
A dynamic mixing apparatus for intensively mixing thermoplastic melt with ingredients contained therein, which comprises:
- source means providing a flowing mass of thermoplastic melt;
- and
- dynamic mixing means receiving and mixing said thermoplastic melt form said source means, comprising:
- inlet means receiving said thermoplastic melt;
- barrel means having an inner cylindrical surface;
- spindle means having a cylindrical surface configuration and being rotatable disposed within said barrel means to define a mixing space for receiving said thermoplastic melt between the said surfaces of said barrel means and spindle means;
- a labyrinth of mixing balls disposed in said mixing space in circumferential rows about the said surface of said spindle;
- said mixing balls being responsive to the rotation of said spindle to rotate in a planetary manner about said spindle to impart an intensive mixing action to said thermoplastic melt;
- the mixing balls in respectively adjacent rows being in staggered relationship with one another to provide a labyrinth of dynamic flow paths for said thermoplastic melt;
- and
- outlet means for receiving mixed thermoplastic melt from said mixing space downstream of said inlet means.
A dynamic mixing apparatus for intensively mixing thermoplastic melt with ingredients contained therein, said thermoplastic melt being in a flowing pressurized mass, comprising:
- housing means having an inner cylindrical surface;
- spindle means having a cylindrical surface configuration and being rotatable disposed within said housing means to define a mixing space for receiving said thermoplastic melt between the said surfaces of said barrel means and said spindle means;
- said mixing space having upstream and downstream locations relative to the flow of thermoplastic melt therethrough;
- inlet means and outlet means at respective upstream and downstream locations in said mixing space for receiving and discharging respectively said thermoplastic melt;
- and
- planetary mixing means defining a labyrinth of dynamic flow paths between said inlet and outlet means within said mixing space, comprising:
- a plurality of mixing balls disposed in circumferential rows about the said surface of said spindle;
- said mixing balls being responsive to the rotation of said spindle within said housing to rotate in a planetary manner about said spindle in said thermoplastic melt to constrain said melt to follow a geometrically increasing labyrinth of flow paths between said inlet means and said outlet means to thereby intensively mix said thermoplastic melt within said mixing space.
The method of incorporating blowing agents in a flowing mass of thermoplastic melt which obviates the need for fluorocarbon blowing agents int he production of foamed thermoplastics, comprising:
- providing a mixing space of substantially tubular configuration having an inlet and an outlet;
- providing a labyrinth of dynamic flow paths in said mixing space which increase in number in geometric progression from said inlet to said outlet;
- delivering a flowing mass of thermoplastic melt containing entrained blowing agent into said inlet and constraining said melt to flow through said labyrinth of flow paths to said outlet while orbiting said labyrinth in planetary fashion within said tubular mixing space.
The method of incorporating and mixing materials in a homogeneous manner in a flow mass of thermoplastic melt, comprising:
- providing a mixing space of substantially tubular configuration having an inlet and an outlet;
- providing a labyrinth of dynamic flow paths in said mixing space which increase in number in geometric progression from said inlet to said outlet;
- and
- delivering a flowing mass of thermoplastic melt containing entrained material to be mixed therewith into said inlet and constraining said melt to flow through said labyrinth of dynamic flow paths to said outlet while orbiting said labyrinth in planetary fashion within said tubular mixing space.
Dependencies are inferred from the claim text.