Fluid flow control system

Abstract

A syringe pump operated by a stepping motor to repetitively fill and empty a syringe cartridge over a plurality of operational cycles of successive fill stroke and pump stroke periods. The motor is driven by drive pulses from a digital pulse generation and control system, the pulse frequency establishing a predetermined fixed rate of fill during the fill stroke and being preselected, in accordance with desired output flow rate, to establish the rate at which the syringe is emptied during the pump stroke. The drive pulse rate during a fill stroke exceeds the maximum pulse rate during a pump stroke and, in order to maintain a proportional relationship between the preselected pumping rate and the actual pumping rate over each complete cycle of successive fill and pump strokes, the drive pulse frequency during each pump stroke is automatically increased to compensate for the time lost during each fill stroke. This is accomplished by accelerating counting up of the electrical network defining each individual pump stroke drive pulse period for a time interval equal to a single fill stroke drive pulse period. A start-up subsystem insures proper cartridge installation prior to initiation of a pumping cycle. Appropriate alarms respond to improper operating conditions including leakage from the source during the pump stroke, empty bottle or insufficient flow during fill, air in the I.V. line, a stalled motor, lack of flow due to system component failure, or occurrence of a runaway high pumping rate.