| 摘要 |
<p>This invention relates generally to improvements in fluid flow control systems for parenteral administration of medical liquids. Positive pressure infusion pumps of the syringe type are known. However, since a portion of each operating cycle with such syringe type pumps is concerned with filling the syringe, rather than delivering fluid to the patient in a pumping mode, the accuracy of such devices tends to fall off, particularly at very high flow rates, where the fill stroke is of significantly large duration relative to the pump stroke period. The present invention overcomes this deficiency by providing a system for fluid flow control utilizing 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 stepping motor is driven by electrical drive pulses from a digital pulse generation and control system. Means are provided for maintaining a proportional relationship between the preselected pumping rate and the actual fluid flow pumping rate over each complete cycle of successive fill and pump strokes, the motor drive pulse frequency during each pump stroke is automatically increased to compensate for the time lost during each fill stroke. A detection device is provided which responds to a high rate of motor drive pulses in the absence of a concurrent selected high flow rate.</p> |
