Donaldson Hy-Pro’s NSD (Non-Spark Discharge) filter element media is specially engineered for bearing lube and hydraulic control systems to eliminate damaging spark discharge and reduce energy potential during fluid flow. By preventing thermal sparking events and minimizing triboelectric charge, NSD elements help protect your fluid from oxidation, keep antioxidant additives intact, and help reduce varnish buildup. Even at high efficiency (3 µm absolute, β5[c] > 4000), these media deliver superior performance without compromising safety or contamination control, helping ensure cleaner, longer-lasting fluid and system reliability.
For some, the answer to preventing element sparking and high potential energy is to use coarse strainer type filters (Stat-Free) in the main bearing lube filter duplex. Although this may prevent sparking it renders the main bearing lube filter assembly useless in preventing catastrophic bearing failure due to contamination. Independent lab analysis proves that even Hy-Pro high efficiency 3 micron absolute (β5[c] > 4000) NSD elements are resistant to spark discharge.
With Hy-Pro NSD elements, any reduction in thermal sparking events and tribo-electric effect will have a positive impact by decelerating anti-oxidant additive depletion and extending useful fluid life. Field test data has shown that Hy-Pro NSD elements may even reduce or stabilize varnish potential values by preventing further degradation from sparking and collecting some insoluble oxidation by-products.
As fluid passes through the typical tortuous filter media fiber matrix, turbulence increases which results in thermal events as the fluid layers shear, creating static accumulation on elements that can lead to high voltage spark discharge from media to support tube. Photos 1 and 2 show evidence of sparking on the filter element support tube (pitting and burning), and photo 3 shows filter media and support mesh from a lube filter element with spark discharge burn damage.
