We recently shared an article with you on the harmful impact varnish can have on your hydraulic systems.
Here, Sam Keating, Laboratory Manager, Fluid Care Division, Hydac Technology Ltd. looks at electrostatic discharge (ESD), which occurs when the oil and filter become electrostatically charged.
ESD occurs due to a transfer of electrons between the materials; the reason for this transfer can be observed in the triboelectric series, identifying the electron affinity of the filter media and of oil.
Filter media is typically glass-fibre, which will prefer to donate electrons and become positively charged, whereas oil will be more willing to receive electrons and become negatively charged. As these materials become separated, there is an increased voltage; once this exceeds 3kV/mm, discharge sparking can occur.