Sealed With a Twist

Posted on Friday, June 21st, 2019 and is filed under Uncategorized

If your seals and bearings are not lasting 30-50 years without damage, you need to ask: Why Not?

Non-maintenance seals from Lignum Vitae North America flip the script on a hydro plants bottom line with performance.

Hydro plant operators have become so accustomed to premature wear and failure of seals and bearings, that failure has become almost acceptable within the industry. Short of weather forecasting and general contracting, in no other industry is poor performance so expected and overlooked. But it doesn’t have to be, thanks to innovative seals engineered by Lignum Vitae North America.

Seals made with genuine lignum vitae are the only seals on the market today that can offer sustained, maintenance-free performance that lasts for decades. It’s true, and there’s proof. Lignum vitae seals were the original seals in our nation’s first hydroelectric power plants and can show decades of superior performance dating back more than 150 years.

This recent project offers an example of how seals made using genuine lignum vitae material are superior to most OEM and replacement composite seal elements:

Background

Hydro Tech, Inc. partnered with Lignum Vitae N.A. to address an ongoing problem: repeated premature failure of resin-composite style seals. The horizontal water S turbine had seen numerous resin-composite seals fail prematurely due to overheating and extensive wear.

Conditions

• Axial, pressure activated turbine seal design.
• Effective seal area:
  • 33 11/16″ outer diameter
  • 31 5/16” inner diameter
• Rated Speed: 327.3 RPM
• Runaway speed: 866 rpm.
• Uses unfiltered river water
• Cooling water: 1.25 USGPM minimum @ 19 psi
• Journal Material: 304 stainless steel

Design & Outcomes

An eight (8) segment brass-backed Lignum Vitae replacement seal and new 350 BHN polished thrust ring were manufactured to fit into the existing seal housing. Some modifications were made to improve water flow and flow direction.

Successful trials with over 20 stops and starts and over 1400 hours of operation, have shown very little break-in wear (<0.08”) and the remaining thickness of the seal has not changed after break-in.

In contrast, the last OEM composite seal, under the same load conditions and with the modified water supply, was completely destroyed after 3 days and 6 stop/start cycles.

It is clear – Lignum Vitae N.A. is delivering global seal and bearing performance that eliminates costly and frequent replacements. Lignum Vitae North America is positively impacting the bottom line for today’s hydro plant operators. Give us the chance to impact yours.