| 主权项 |
1. A medical fluid pumping system, comprising:
a medical fluid pumping machine comprising a drive mechanism comprising a motor; and a medical fluid delivery set comprising a single-chamber syringe that can be operatively connected to the drive mechanism and a series of interconnected fluid lines, the series of interconnected fluid lines comprising a dialysis solution line configured to be connected to a dialysis solution container during a dialysis treatment, the syringe comprising a medical fluid containment cylinder; a plunger assembly that can be axially moved relative to the medical fluid containment cylinder, the plunger assembly comprising
an inner plunger shaft comprising a first seal that is slidably disposed within the medical fluid containment cylinder such that a substantially liquid-tight seal is maintained between the first seal of the inner plunger shaft and an inner surface of the medical fluid containment cylinder as the inner plunger shaft slides axially within the medical fluid containment cylinder, the first seal of the inner plunger shaft and the medical fluid containment cylinder cooperating to at least partially define a fluid pump chamber, andan outer plunger shaft that at least partially surrounds the inner plunger shaft to form a space between an outer surface of the inner plunger shaft and an inner surface of the outer plunger shaft, the space being sized to receive a wall of the medical fluid containment cylinder therein, and the outer plunger shaft forming an outer circumferential surface of the syringe; and a second seal positioned between an outer surface of the medical fluid containment cylinder and an inner surface of the outer plunger shaft such that a substantially liquid-tight seal is maintained therebetween, wherein the second seal is coupled to the outer surface of the medical fluid containment cylinder and the first seal is coupled to the inner plunger shaft such that the first seal moves relative to the second seal when the plunger assembly is moved relative to the medical fluid containment cylinder, and wherein, when the syringe of the medical fluid delivery set is operatively engaged with the drive mechanism, the motor can be rotated to axially displace the plunger assembly relative to the medical fluid containment cylinder to force a medical fluid out of the fluid pump chamber and to draw the medical fluid into the fluid pump chamber. |
