Method and apparatus for monitoring a spark discharge particle generator

Nanoparticle-oriented research is going strong today due to their unique properties and the special applications made possible by their use. Increased interest in the research of the properties and applications of nanoparticles has led to the development of methods suitable for the production of nanoparticles. One of the most promising productive, physical means of nanoparticle generation methods are based on the use of electrical discharge plasmas, such as the spark discharge. Spark generators use a high voltage spark discharge (high temperature plasmas) to erode the material of two electrodes to produce the nanoparticles. The continuous real-time monitoring of the operation of these discharge generators can largely contribute to maintaining the production of a uniform quality and yield of nanoparticles. Our technology performs optical monitoring via fiber-optic based collection of the light emitted by the high voltage spark plasma operated inside the generation chamber. The emission spectrum of the plasma is processed and evaluated real-time to obtain information about the „health status” of the generator so that deviations from normal operating conditions can be detected and control/feedback/alarm signals can be provided. A great advantage of our monitoring concept is that can be easily scaled up to monitor multiple generators „in parallel”, hence it can be efficiently integrated into industrial facilites.

Nanoparticle production by generators at present are typically performed ex situ, that is by collecting the generated particles and characterizing their properties off line. This is a direct, but time consuming, largely manual procedure, not very suitable and efficient for use in an industrial setting. Other approaches use high-cost, complex instrumentation (e.g. X-ray spectrometers) to collect online monitoring information. At the same time, our fiber optics based UV-Vis emission spectroscopy approach is cost-efficient, robust, flexible and is easy to scale up technology. The number of generator units that can be monitored by a single device can be several dozen or more. The monitoring is done in a time-sharing sequential way, therefore the number of monitored generator units (N) is mainly limited by the discharge repetition rate only. For low frequency units, N can be proportionally higher than for high frequency units.
The prototype of our monitoring system has already been tested successfully not only in the laboratory, but also in nanoparticle generation facilities at several locations in Europe. Among other tests, it was successfully used to monitor three high frequency spark generators running in parallel, as well as in a pilot plant composed of 32 electrical discharge generators.

Desired business relationship

Patent licensing

Technology development

New technology applications

Current development status

Laboratory prototypes