Injection system for foamable compositions

A self-cleaning injection system for injecting foamable compositions into packaging applications, the system comprising:

• an injection nozzle assembly comprising,
• a housing for receiving foam precursors and allowing then to mix therein and having an opening in one end thereof from which mixed foam precursors which form foamable compositions may exit, said one end comprising a tip assembly which is adjacent the outer exit portion of said housing and which is porous to gases and to certain liquids, but which is impermeable to other materials such as the foamable compositions which may otherwise exit the housing only through said opening,
• a valving rod longitudinally disposed within said housing and longitudinally movable therein and having a cross-sectional profile substantially equivalent to the cross-sectional profile of said opening in said porous tip assembly in said housing so that the movement of said valving rod into and out of said opening respectively closes and opens said opening to the exiting of foamed precursors therethrough,
• means for moving said valving rod into and out of said opening to thereby respectively close and open said opening;
• and
• means for delivering a solvent for which foamable compositions are soluble to, through and out of said porous tip assembly and out of said housing adjacent said outer exit portions of said housing so that the delivery of solvent to and out of said tip assembly removes foamable compositions from said outer exit portions of said one end of said housing and keeps said injection nozzle clean and in optimum operating condition.

A pump assembly for pumping cleaning solvent from a solvent container while maintaining a constant delivery of air or a mixture of air and solvent to a self-cleaning injection nozzle having a porous tip through which cleaning solvent may pass when said injection nozzle is used to deliver foamable compositions into packaging applications, the pump assembly comprising:

• a solvent container;
• an air compressor for sending air to said solvent container and for sending a mixture of solvent and air from said solvent container to an injection nozzle;
• a bellows on said solvent container and in air flow communication with said air compressor for being raised and lowered in response to an increase in the flow of air from said air compressor;
• a pump head in air flow communication with said bellows and having an inlet connector for receiving compressed air and an outlet connector for dispensing compressed air, solvent, or a mixture of air and solvent, said pump head being at least partially fillable with solvent from said container;
• a connecting tube extending downwardly from said pump head to lower portions of said solvent container and through which solvent from said container may pass to said pump head;
• an upper piston operatively associated with said bellows for being raised and lowered concurrently therewith;
• a connecting rod operatively responsive to the raising and lowering movement of said upper piston;
• a lower piston positioned at the lower end of said connecting tube for drawing solvent from said solvent container into said connecting tube and responsive to the movement of said connecting rod;
• and
• means for placing said outlet connector of said pump head in communication with a self-cleaning injection nozzle whereby an increase in the flow of air into said bellows lifts said bellows, said upper piston, said connecting rod, and said lower piston, to thereby draw solvent into said connecting tube and up to and out of said pump head and to said self-cleaning injection nozzle.

A self-cleaning injection system for injecting foamable compositions into packaging applications, the system comprising:

• an injection nozzle having an opening in one end thereof from which mixed foam precursors which form foamable compositions may exit, said one end comprising a tip assembly adjacent the outer exit portions of said injection nozzle and which is porous to gases and to certain liquids, but which is impermeable to other materials such as the foamable compositions which may otherwise exit said injection nozzle only through said opening;
• and
• a pump assembly for pumping cleaning solvent from a solvent container to said injection nozzle while maintaining a constant delivery of air or a mixture of air and solvent said injection nozzle, said pump assembly comprising,
• a solvent container, and
• an air compressor for sending air to said solvent container and for sending a mixture of solvent and air from said solvent container to said injection nozzle;
• and
• means for placing said pump assembly in communication with said injection nozzle whereby a mixture of air and solvent may be sent from said solvent container to said pump assembly, to said injection nozzle and out of said porous tip assembly, thereby helping to clean accumulated foamable composition from said outer exit portions of said injection nozzle.