Abstract
This paper describes an adjustable flow restrictor for use in gas-driven implantable infusion pumps, which is based on the resistance of a flow through a porous ceramic material. The flow inside the walls of a ceramic tube can be adjusted between 270 nl/min and 1260 nl/min by changing the flow path length in the ceramic over a distance of 14 mm. The long-term stability of the flow restrictor has been analyzed. A drift of -8% from the nominal value was observed, which lies within the required tolerance of ±10% after 30 days. The average time needed to change the flow rate is 40 s. In addition, the maximum adjustment time was 110 s, which also lies within the specification.
Acknowledgments
The authors would like to thank the German Federal Ministry for Education and Science for funding the project “VarioPump” within its program “Intelligente Implantate” (BMBF 16SV3784) and the company Tricumed Medizintechnik GmbH, Kiel, for the good cooperation.
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