| 摘要 |
<p>1513902 Automatic control IVAC CORP 11 June 1975 [28 Feb 1975] 24941/75 Heading G3N Parenteral administration of liquids is effected by a disposable cartridge syringe 10, having a piston 10c driven by a D.C. stepping motor forming part of a drive subsystem 12. Selective actuation of valves 17, 18, of the tube-pincher or clamp-type, during fill and delivery strokes of the pump is determined by a valve subsystem 19, geared to the drive subsystem. The subsystem 19 provides piston direction signals to a control subsystem 13 which controls subsystem 12 to determine direction and rate of piston drive. The control subsystem 13 provides a fixed motor drive frequency during the fill stroke and compensates, as the desired fluid pumping rate is increased, for the time lost during the fill stroke period, by increasing the drive frequency during the pump stroke. The compensation is spread over the full stroke period by compensating each motor pulse for a uniform position of the time lost during the immediately preceding full stroke. The output of a drop detector and of alarm subsystems (responsive to detection of a bubble, or stalled motor) are fed to the control subsystem 13 and an arrangement is provided to ensure that the piston is positioned at start-up so as to facilitate insertion of a syringe cartridge.</p> |
