Microdiaphragm pumps need compact drives which can provide a constant flow, as well as variable flow rates.
Due to the small volumes per pumping cycle, high cycle rates of up to several 10 kHz are necessary to achieve high flow rates.
A microdiaphragm pump comprises a valve unit and the pump diaphragm which, together with the piezoelectric actuator, form the pump drive.
The metered amounts range from the milli, micro and nano to the picoliter range.
The fields of application for piezoelectric micropumps are in laboratory technology, medical technology, biotechnology, chemical analytics and process engineering, which require reliable metering of minute amounts of liquids and gases.
Microdiaphragm pumps, micrometering valves
Disk-shaped piezo actuators can be mounted directly on the diaphragm to deflect it. Larger strokes or forces can be achieved if a diaphragm or a piston is coupled directly to a piezoelectric actuator. Due to their compact dimensions and the low energy requirements of piezo elements, these metering devices are also suitable for lab-on-a-chip applications.
Piezo drives are also used for opening and closing valves. Here, the piezo product range is from simple piezo elements or bending actuators for diaphragm valves, to preloaded piezo stack actuators for large dynamics and forces, to piezo levers, which carry out very fine metering, even at high backpressure.
In the automotive industry, micrometering valves for fuel injection systems are also driven by multilayer stack actuators.
Peristaltic Pumps
Whenever liquids or gases are to be metered accurately, as uniformly and with as little pulsing as possible, the solution of choice are so-called peristaltic pumps. In this type of pumps, the external mechanical deformation of the hose forces the medium to be transported through this hose. The pumping direction is determined by the control of the individual actuators.
The drive element consists of low-profile piezo bending elements, compact piezo chip actuators or piezo stack actuators, depending on the power and size requirements. Bending actuators are suitable mainly for applications with low backpressure, for example, for low-viscosity liquids.