Reference Filters for Electrostatic Charging Tendency Measurements of Fuels

摘要

A study has been made to determine whether laboratory filter papers might be suitable as reference filters for the determination of charging tendencies of jet fuels as measured in the EXXON Mini-Static Tester (MST). From the filter papers which were investigated it was concluded that, compared to commercial fuel filters, these filters do not generate enough charge to afford repeatable and reliable measurements. Some correlation was observed between the polarity of the generated charges and the nature of the filter paper surfaces. However, attempts to repeat these experiments after a time period of about six to eight months were unsuccessful because of variations in the data, particularly that of polarity of the charge. It is suggested that the variations may have been due to relative humidity and temperature changes in the laboratory over the time period. Another possible explanation might be that there were changes in fuel composition due to degradation. A few studies of some ion exchange resin coated filter papers suggest some tentative generalizations regarding these papers. It was observed that the flow rate of fuel through each type of filter was not constant for any given run. Since it was necessary to have accurate flow rate data for each filter in order to be able to calculate charging tendency from the measured streaming current, a method was devised to make this measurement.