Patent ID: 6997910

Claim:
A multi-chamber syringe apparatus for sequentially dispensing medical fluids, said apparatus comprising: a syringe barrel which is concentrically disposed about an elongated medial axis, said barrel comprising an open proximal end and a distal end having a closed interior surface about an orifice through which fluid is transferred, said surface having a substantially concave shape; a plunger and plunger stopper combination disposed to be displaced within said barrel for dislocating fluid thereby; and a valve assembly disposed within said barrel between said plunger stopper and said distal end to provide a proximal chamber between the valve assembly and plunger stopper and a distal chamber between the valve assembly and said interior surface; said valve assembly comprising: a valved stopper comprising a distal face and a hollow, grooved, cylindrical interior which opens proximally toward said plunger stopper and which communicates with said plunger stopper via fluid within the barrel, therebetween, to be displaced as the plunger stopper is displaced; said valved stopper further comprising an operable, normally closed valve, which permits displacement of fluid therethrough only when open, and a pliable material whereby said distal face cooperatively conforms to the shape of the interior surface when forced thereupon; and a valve actuator comprising features which are complimentary to grooves of the interior of the valved stopper whereby the actuator is securely affixed to the valved stopper and is displaced as the valved stopper is displaced; said actuator further comprising structure for sensing impact between said distal face and said interior surface and, upon sensing the impact, reactively causes said valve to open.