Debiotech S.A of Lausanne, Switzerland has produced the first prototypes of the company’s tiny insulin pump, a device we’ve reported back in April 2007.
The working principle is a volumetric membrane pump, with a pair of check valves, integrated in a MEMS chip. The chip is a stack of 3 layers bonded together: a silicon on insulator (SOI) plate with micromachined pump-structures and two Pyrex cover plates with through-holes. This MEMS chip is assembled with a piezoelectric actuator that moves the membrane in a reciprocating movement to compress and decompress the fluid in the pumping chamber.
The design and manufacturing process of the Nanopump™ starts with silicon on insulator (SOI) wafers. Such wafers are used as the starting material in the fabrication of the latest and fastest computer chips. For the Nanopump™ the SOI wafers allow to increase the precision while shrinking the size of the chip. At its small size, numerous chips can be manufactured at the same time on one wafer, minimizing the cost per chip.
Constant and accurate flow rate is guaranteed through the control of the displacement of the pumping membrane. The movement occurs between two mechanical stops defined by the construction of the chip. As a consequence, the flow rate is linear with actuation frequency and virtually insensitive to inlet and outlet pressure, actuation voltage, temperature, viscosity and aging.
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