A research group from Saarland University has developed valves and pumps from a silicone film, allowing them to be precisely controlled electronically. Using responsive film movement, the flow can be continuously controlled and the pump performance can be varied.
Engineers Philipp Linnebach (left) and Steffen Hau (right) from Saarland University with the prototypes of the motorless pump (centre) and smart valve (front right).
Oliver Dietze
In large industrial plants, it can be a long time before faults with small valves or pumps are detected. This can be all the more problematic if the fault took time to reveal itself; the longer it takes to find a fault, the greater the potential damage to the plant. Thankfully, this is no longer an issue with the novel pumps and valves that have been developed by Professor Stefan Seelecke and his research team at Saarland University. They are able to communicate their status and functionality. In addition, they can signal if a foreign body is blocking a valve.
The valves and pumps created by the research group are made from a thin silicone film that is printed on both sides with an electrically conducting material. Scientists refer to these materials as dielectric elastomers. "If we apply a voltage to the film, it generates an electrostatic attractive force that compresses the film, causing it to expand out sideways," says Steffen Hau, a PhD engineer in Seelecke's team. By altering the applied electric field in a controlled manner, the engineers can make the film undergo high-frequency vibrations or continuously variable flexing motions. It can also adopt any desired position. "These properties mean that the film can be used to design novel drive systems," explains Hau.
Compact and energy efficient
Using intelligent algorithms to control the movement of the film, the researchers at Saarland University and at the Centre for Mechatronics and Automation Technology (ZeMA) are developing self-regulating valves and motorless pumps. Since the pumps do not require a motor, they are compact, flat and very energy efficient. The film-based valve consumes up to 400 times less energy in comparison with solenoid valves. The film can be adapted to fit any housing shape. The volume flow rate in these pumps can be controlled using the amplitude of the applied voltage rather than the frequency, which is what is normally used. This makes it possible to produce very quiet pumps. The motion sequences can be calculated and programmed accurately in a control unit. This allows the film valve to dose compressed air or liquids precisely as required.
