MULTI-STAGE FLUID DELIVERY DEVICE AND METHOD

摘要

A fluid delivery device for delivering a substance to a patient by way of infusion delivers the preparation at a rate of flow which varies in steps fr om a substantially constant higher rate, to a stepped-down substantially consta nt lower rate or rates. The delivery device includes one or more reservoirs (A, B, N) and one or more Belleville springs for applying generally constant pressures to the substance contained in the reservoirs. Each reservoir will have a different constant pressure applied in a mid-range of operation. The reservoirs can be interconnected (10) to each other and to an infusion devic e (13) in a number of arrangements, including various manifolds and flow restrictors (11), such that the rate of flow is controlled in steps in accordance with the pressures applied by the springs of the plurality of reservoirs.