PRODUCT INNOVATIONS
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Fraunhofer-Gesellschaft - micro-pump systems
An innovative micro-pump makes it possible for tiny quantities of
liquid – such as medicines – to be dosed accurately and
flexibly. Active composites and an electronic control mechanism ensure
that the low-maintenance pump works accurately – both forwards
and backwards.
Medicines sometimes have to be administered in extremely small
quantities. Just a few tenths of a milliliter may be sufficient to give
the patient the ideal treatment. Micro-pumps greatly facilitate the
dosage of minute quantities. Pumps like these have been built and
constantly optimized for over 25 years. They find application in
numerous areas – from medical engineering to microproduction
technology – wherever tiny volumes have to be variably dosed with
extreme accuracy.
However, these micro-pump systems are usually not as flexible as
desired: They often work in only one direction, bubbles in the liquid
impair their operation, they do not tolerate bothersome particles, they
have a fixed pump output and they contain expendable parts such as
valves or cogwheels. Together with partners from research institutes
and industry, researchers at the Fraunhofer Institute for Mechanics of
Materials IWM in Freiburg have developed an innovative pump system that
solves all these problems: a controllable peristaltic micro-pump.
“The peristaltic pump is a highly complex system,” explains
IWM project manager Dr. Bärbel Thielicke. “It contracts in
waves in a similar way to the human esophagus, and thus propels the
liquid along – it changes shape of its own accord. To achieve
this, we had to use a whole range of different materials and special
material composites.” The researchers use lead-zirconate-titanate
(PZT) films that are joined in a suitable way with bending elements
made of carbon-fiber-reinforced plastic and a flexible tube. “PZT
materials change their shape as soon as you apply an electric field to
them. This makes it possible to control the pump system
electronically,” says Thielicke. Special adhesives additionally
hold the various components of the pump system together. Thanks to the
special control electronics, tiny quantities can be pumped accurately
through the system.
The peristaltic pump system has already passed its first functional
tests. Now the researchers are working to adapt the peristaltic
micro-pump to the various different applications. “We work with
special simulation models to do this,” says Thielicke. “We
calculate in advance how the structure of the pump needs to be modified
in order to administer other dosages or other liquids. This helps us
save time and money during the development phase.”
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