Patent ID: 7935078

Claim:
A multi-chamber syringe comprising: a barrel, having a substantially consistent inner shape along the length of the barrel, and having an open end and a choked end, the choked end having an injection hole; a push member disposed to fit an inner side surface of the barrel and slidable on the inner side surface; and an elastic plug having a substantially columnar main body of a diameter smaller than the inner side surface of the barrel, a flange provided on a side surface of the main body at an end closer to the open end for contacting the inner side surface, and a flange provided on the side surface of the main body at an end closer to the choked end for contacting the inner side surface, the elastic plug being disposed more closely to the choked end than the push member, to fit the inner side surface and slidable on the inner side surface; the plug partitioning an inside space of the barrel into two chambers each capable of storing a fluid; the syringe further comprising: a first projection with an eccentric top, provided on a first main surface of the plug, said first main surface facing the choked end of the barrel; and an annular flow path made between the inner side surface of the barrel and a portion of the main body of the plug disposed between the flanges, wherein application of a pressure from an open end side to the plug, with the first projection contacting with the choked end, causes the plug to tilt in the barrel, makes a first gap opening at only a portion of the flange on the open end side, while maintaining contact of the remaining portion of the flange with the inner side surface, and the first gap opening communicating with the flow path, and makes a second gap opening, which is substantially diametrically opposite to the first gap opening in a circumferential direction of the annular flow path, said second gap opening at only a portion of the flange on the choked end side, while maintaining contact of the remaining portion of the flange with the inner side surface, and the second gap opening communicating with the flow path, so as to provide a path for flow of substantially all of a fluid stored between the elastic plug and the push member through the first gap opening, then circumferentially through the annular flow path, and then through the second gap opening.