Patent ID: 7270648

Claim:
A fluid dispensing device comprising: (a) a first syringe having a reservoir with an outlet port, the reservoir adapted to hold a liquid medicament to be dispensed, and a plunger for ejecting the liquid medicament from the reservoir through the said outlet port; (b) a second syringe having a reservoir with an outlet port, the reservoir of the second syringe adapted to contain a fluid, and a plunger for ejecting the fluid from the second reservoir; (c) a link member coupling the plunger of the second syringe to the plunger of the first syringe so that both said plungers will move in unison; (d) a double coil constant force spring or a helically wound constant torque spring contiguously coupled to the plunger of the second syringe to impart a generally constant force to the plunger of the second syringe; and (e) a flow rate control device coupled only to the outlet port of the reservoir of the second syringe for controlling the rate of displacement of the plunger of the first syringe as it is made to move in unison with the plunger of the second syringe.