US Patent 7101354 Mixing syringe with and without flush

A displaceable valved stopper is disclosed which partitions a conventional syringe into proximal and distal chambers to provide a multi-chamber, mixing syringe assembly. Also the valved stopper and a valve assembly are disclosed for use in a single conventional syringe to provide dual chamber mixing plus a disparate and sequentially dispensed flush. Incorporated in the valve assembly is another valved stopper and a separator which filters out gas from liquid being dispensed through the valve assembly. Each valved stopper is made as a single molded part which may be made from basic syringe plunger material. Also, each valved stopper may have a bi-state valve (e.g. a domed, slit valve). The separator is a single molded part which may be molded from basic syringe material. Each valve is actuated to a different state by differential pressure of a force greater than the associated valved stopper displacement force. A syringe plunger communicates through fluid in a more proximal chamber to force displacement of the valved stopper and valve assembly for both mixing and dispensing.