It pays dividends to consider the most rugged and fault-tolerant material known when looking for a retrofit or newbuild seal option.
Lignum vitae is well known as the hydro industry’s original bearing material. This high-density wood has incredible compressive strength, self-healing properties and innate lubricity from a natural resin embedded in its structure. It is a proven solution for water-lubricated bearings on everything from aircraft carriers to Hydro applications – and now, it can be used for sealing as well.
In partnership with engineering consultancy Hydro Tech, Inc., Lignum Vitae North America (LVNA) has developed a line of seals to solve problems with premature failure of the standard resin-composite materials. The project was initiated for an Upstate New York-based utility, which had a horizontal water turbine that had seen numerous resin-composite seals fail prematurely due to overheating and wear. To solve these problems, LVNA manufactured a drop-in replacement seal of about 33 inches in diameter with a brass backing, designed to fit right into the existing seal housing.
The previous seal material was failing within as little as three days and six stop/start cycles. With the new lignum vitae seal, a break-in period of 1400 hours of operation and 20 stop/start cycles caused very little wear (less than 0.08 inches), and the remaining thickness of the seal did not change after break-in.
“Lignum vitae is an anomaly of nature and is the only known wood with no silica. It has an innate lubricity originating from guaiac resin imbued in every cell and a hardness like aluminum, based on its long-chain tenacious molecular cellulose structure. The mixture of the smooth resin bound up in an extremely dense cellulose structure yields a natural bearing material with a high lubricity and a massive compression strength,” says Bob Shortridge, founder and president of LVNA. “Bearings made from lignum vitae, simply put, are self-lubricating in water and conform by self-healing. The nature of the material is inherently able to adapt to extreme and dynamic operating environments with less than perfect shafts. It is startlingly that simple.”
No synthetic material can outcompete tried and true lignum vitae in real-world bearing performance. LVNA is proud to be leading the way with a sustainable supply of renewable lignum vitae that exceeds every environmental standard and solves EPA compliance requirements. Contact us to see how the Lignum Vitae North America personalized approach can lead to the solution for your needs.
Special thanks to Paul Benecki with Maritime Executive for providing article content.