Frothing method and an apparatus for carrying out the method
AssigneeThe Upjohn Company
InventorDietrich Muhle
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Abstract
The invention relates to a frothing method for mixing a liquid propellant having a low boiling point with further components for the production of foamed material, more particularly polyurethane. The invention also relates to an apparatus for carrying out the method with a mixing head for high pressure mixing of the main components in a mixing chamber. The foam production is carried out in two stages involving a first chamber for receiving and premixing reactive polymeric components, and a second chamber intersected by the first into which the mix components are advanced while the frothing propellant is injected at the intersection. The frothed reactive polymeric mix is then discharged from the second chamber into a suitable mold for forming the finished polymerized product.
Claims12
In a frothing method for mixing a liquid propellant having a low boiling point with further components for production of foamed material, the steps which comprise
- separately injecting said further components under high pressure into a first cylindrical mixing chamber closed at one end and open at the other, to produce a first-stage, reactive mix in said first chamber;
- advancing said first-stage mix through the open end of said first chamber to a second cylindrical mixing chamber, larger than the first and intersected by the first at the open end of the latter, said second chamber being closed at an axial end adjacent said intersection but open at its opposite axial end;
- introducing said liquidified propellant into said first-stage mix through a port in said second chamber at said intersection of said chambers, whereby to provide a second-stage mix in said second chamber;
- and
- then discharging said second-stage mix from said open end of said second chamber to allow said mix to expand and form said foamed material.
In a high pressure mixing head for producing a foamed material by mixing a liquified propellant having a low boiling point with further components for the production of said foamed material, said mixing head comprising in combination
- a first cylindrical mixing chamber closed at one end and open at the other, and ports opening into said chamber intermediate its axial ends, said ports respectively allowing injection therethrough into said chamber of said further components to produce a first-stage mix;
- piston means for controlling the injection of said further components through said ports and for advancing said first-stage mix out of said open end of said first chamber;
- a second cylindrical mixing chamber, closed at one end and open at the other, said second chamber being larger than the first and disposed with its axis intersecting the axis of said first chamber intermediate the axial extent of said second chamber to receive said first-stage mix;
- port means opening into said second chamber adjacent said intersection of said chambers, and means for introducing said liquified propellant through said port means in countercurrent flow relation to said first-stage mix to produce a second-stage mix;
- piston means for advancing said second-stage mix through said second chamber and out the open end thereof, said means also acting to interrupt introduction of liquified propellant at said second chamber port means during discharge of said second-stage mix from said second chamber.
Dependencies are inferred from the claim text.