Patent ID: 7048720

Claim:
A multi-chamber syringe apparatus for sequentially dispensing medical fluids, said apparatus comprising: a syringe barrel having an internal surface which is concentrically disposed about an elongated medial axis, said barrel surface comprising an open proximal end and a distal end having a closed interior about an orifice through which fluid is transferred; a stem and plunger combination disposed to be displaced within said barrel by application of a directional force against said stem for dislocating fluid thereby; and a valve assembly which, when disposed within said barrel between said plunger stopper and said distal end, provides a proximal chamber between the valve assembly and plunger stopper and a distal chamber between the valve assembly and said closed interior surface; said valve assembly comprising: a valved stopper comprising a normally closed, medially disposed valve in a distal face of the stopper and a hollow, grooved, cylindrical interior which opens proximally toward said plunger and which communicates with said plunger stopper via fluid, within the barrel, said valved stopper being distally displaced toward said distal end within said barrel when acted upon by a force directionally applied toward said distal end which produces a first differential pressure and being proximally displaced away from said distal end when acted upon by an oppositely directed force of a second differential pressure; and said valved stopper further comprising structure which only opens said valve to permit fluid flow there through when said stopper is acted upon by force of a third differential pressure which is in the same direction as force from the first differential pressure, the magnitude of the third differential pressure being greater than the first differential pressure.