Method for measuring the electrostatic charge in laminar and turbulent flows

The new technology is based on two-dimensional measurements using particle image velocimetry (PIV). Between two measuring sections, an electrostatic field is applied to a testing channel. The differently charged particles are deflected by this field. By observing the dynamics of the individual particles in these measurement areas, the novel technique detects the change in charge in the flow direction. Thus, it is possible to spatially resolve the charge and not just measuring the absolute charge as done in established methods. Furthermore, the new technique enables to measure the electrostatic charge of both laminar and turbulent flows of powders or liquids online and non-invasively. This measurement method therefore helps to improve the safety of many transportation processes.
From the point of view of explosion protection, it is essential to understand precisely how powders or liquids charge during transport in industrial plants. During the pneumatic transport of powders, individual particles can become electrostatically charged. Due to the triboelectric effect, the electrostatic charging of flows can trigger explosions. In conventional measurements using a Faraday cage, however, only the sum of the charge of all particles can be measured. The proposed PTB invention allows for the first time to measure the charge of turbulent flows and is in principle suitable for powder and liquid flows.
Economic significance:
The method is suitable for applications in all sectors that transport liquids or powders, e.g. in the pharmaceutical, food and mineral industries. In addition, future use is conceivable by companies whose products are based on the electrostatic charging of flows, such as triboelectric sorting or powder coating.
Development status:
A German patent has already been granted for the invention. Licenses for use are available.
Innovations & Advantages:
-        Spatially resolved and non-invasive measurement of electrostatic charges in flows
-        Extended application range for turbulent flows
-        Suitable for powders and liquids