Patent ID: 8277434

Claim:
A method for dosing a substance, the method comprising: providing a dosing device, the dosing device comprising a dosing unit having a variable volume contained within the dosing unit and at least one opening in fluid connection with the variable volume, a supply conduit connected to the dosing unit and in fluid connection to a reservoir containing the substance, and a dispensing conduit connected to the dosing unit and in fluid connection to a dispensing unit of an infusion system, the dosing unit being operable in a first state in which the variable volume is in fluid connection to the reservoir through the at least one opening but is not in fluid connection to the dispensing conduit, in a second state in which the variable volume is in fluid connection to neither the reservoir nor the dispensing conduit, or in a third state in which the variable volume is in fluid connection to the dispensing conduit through the at least one opening but is not in fluid connection to the reservoir, wherein the dosing unit is operable to be moved to select the first state, the second state, or the third state; selecting the first state of the dosing unit; filling the substance into the variable volume through the supply conduit and the single opening, such that the variable volume enlarges while the substance enters the variable volume; moving the dosing unit so as to move, rotate, or displace the at least one opening and select the third state of the dosing unit; and dispensing the substance through the at least one opening and into the dispensing conduit by decreasing the volume of the variable volume.