Vacuum filling of syringe liquids with outgassing compensation stroke

Abstract

A method of filling pharmaceutical syringes with fluid in a machine having a reservoir, vacuum source, pump an actuator that holds a vacuum adapter, sealing element and filling needle over a syringe. The method includes drawing a vacuum during a critical step while maintaining a constant fluid level in the filling needle to avoid overfilling or under filling.

1 . A method of filling syringes with fluid in a machine having a reservoir, vacuum source, rotatable piston pump, and actuator arm that holds a vacuum adapter, sealing element and filling needle, the method comprising:
 A) filling the pump with fluid by raising the pump piston;   B) rotating the piston thereby opening a flow path from pump to fill needle;   C) drawing a vacuum on the vacuum adapter and syringe from the vacuum source and simultaneously raising the piston thereby maintaining a constant fluid level in the filling needle and removing air from the syringe needle;   D) lowering the piston thereby discharging fluid into syringe and syringe needle;   E) releasing the vacuum and continuing the discharge of fluid into the syringe; and   F) raising the actuator arm and vacuum adapter as the liquid level rises in the syringe until the proper volume has been filled in the syringe, thereby completing the cycle.   
   
   
       2 . The method of  claim 1  wherein there are multiple actuator arms, vacuum adapters, sealing elements and filling needles that fill multiple syringes simultaneously. 
   
   
       3 . The method of  claim 2  wherein the method can be used in a machine having between 1 and 10 fill needles.