Field Trial 1: This measured the downstream charge on a hydraulic system at a transformer radiator manufacturing plant. The cartridge charge collector setup was connected to a port on the filter housing downstream of the filter media. Visual and auditory tests were also conducted in the reservoir because plant workers had complained about sparking in the reservoir that they believed was caused by electrostatic discharge at the filter/fluid interface. Both the ESD and the standard glass filters were tested. Tests showed that the ESD material reduced the downstream oil charge to a negligible amount and completely eliminated the noticeable discharge within the reservoir.
Field Trial 2: This set of tests was conducted on an injection molding machine hydraulic system involving three separate styles of filter media: standard glass material, standard glass material with a conductive mesh and the new ESD material. The tests were performed with the cartridge charge collector connected to the downstream port of the filter housing. The testing also included visual examinations for possible effects of electrostatic discharge, as well as auditory tests.
Both the visual and auditory tests checked for phenomena caused by discharge from the filter element to the grounded housing. The standard glass filters were the only ones that exhibited either clicking sounds form the filter housing, and/or visible burn marks on the plastic end caps of the filters.
In addition, the standard glass filter showed a downstream potential of 12V-14V. The new ESD material was the only one that showed lower voltages than the standard glass fiber with 4V-5V measured, while the glass filter with conductive mesh was measured at 14V-16V under the same conditions.
Field Trial 3: Testing was arranged at a paper mill on a hydraulic system. Tests were run using both the glass filter material with conductive mesh and the ESD filter material. The cartridge charge collector was used, and the downstream voltages were measured at different flow-rates through the collector at the same system flow. At the maximum flow measured downstream. The data taken was commensurate with data obtained in earlier lab testing under similar conditions.
Field Trial 4: The fourth set of tests was run at a power plant on a power generation lube system. Testing was done on a different type of glass filter than previously tested (supplied by a different manufacturer). This new glass filter had a metal gad-plasma treated glass fiber mesh downstream of the filter material. Two different grades of the filter were used: β15 ≥ 200 and β41 ≥ 200. Both of these are much coarser then the ESD filter tested previously, β3 ≥ 200, per ISO 16889
Field trial details at http://pall.tekgroup.com/pdf/10005/IFPE-Static_charge.pdf
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