Measurement of the charge transferred by a single electrostatic discharge by acoustic method

Rapid development of new technologies has recently made possible using the state-of-the-art nonmetallic materials in industrial explosive zones, what increases the efficiency of industrial processes and the safety of their use. Due to their properties, such materials may be electrified and be a source of ignition in the explosive atmospheres. That is why we found it necessary to test these materials (which due to their electrostatic discharge energy pose an explosion hazard) for their ability to ignite the explosive mixture, by electrostatic discharge (ESD). The parameter which determines the ability to cause an ignition by electrostatic discharges is charge transferred in a discharge. The electrical methods of charge transferred measurements used so far have significant disadvantages, which in some cases exclude the possibility of obtaining the correct result of. A detailed analysis of the phenomenon of a single ESD enabled the development of new method of measuring the transferred charge by means of measurement and analysis of acoustic phenomena in the hearing range accompanying the discharge. The acoustic method does not have any electrical defects in the measuring circuits and allows measuring the transferred in a first single discharge. The article describes possibility of using an acoustic measurement method to determine the transferred charge of a single ESD from the electrified surface of non-metallic material, what is indispensable to assess the safety of using such material in potentially explosive atmosphere. The method of creating a shock wave resulting from a single ESD, the test stand, the measurement procedure and the test results are described. The acoustic method is an alternative (complementary) testing procedure for transferred charge measurement, based on the analysis of the time process of the sound pressure accompanying the ESD.