Well-Oiled

Lubrication is critical to keeping moving parts in machinery operating smoothly and efficiently, achieved by creating a thin film of fluid as separation between the seals and hardware. Without it, damage to seals and hardware is likely, leading to downtime and losses in productivity.

"Modern hydraulic fluids give excellent protection against wear and corrosion; the problem is that as the focus has been on the primary seal sealing lubricant in, sometimes this can prevent lubrication from reaching the contact area of other sealing system elements, stopping the benefits of lubrication on the contact surface," says Henrik.

In a wind turbine's pitch cylinder, for example, short-stroke service and years of 24/7 cycling means that lubrication is often not reaching the elements "downstream" of the primary seal, resulting in wear and damage from dry-running.

Trelleborg Sealing Solutions has been hard at work developing proprietary and patented methods for improving performance in applications that have been seeing failures and damage resulting from dry-running. Sealing configurations are based on a new sealing technology termed Lubrication Management.

The primary seal still protects against system pressure, but by carefully modifying seal geometry, small quantities of lubricating media are allowed to enter the contact zones during the outstroke. This significantly reduces friction and further protects the hardware and seals, ensuring adequate fluid can reach all sealing elements and increasing total system lifetime

“Usually, to achieve the same lubrication, a drain line would need to be installed behind the primary element, to prevent over-pressure and seal blow out. But engineers at Trelleborg Sealing Solutions decided to rethink classic approaches and combine some of their most effective technologies to develop a wholly new solution,” continues Henrik.

The Turcon® Stepseal® V range of seals features a unique, patented hydrostatic relief channel.

Our new Turcon® Stepseal® V LM offers increased pressure balancing during operation, which protects secondary seals regardless of the service conditions, and is part of the secret to its low-friction performance.

"Combining this feature with our Lubrication Management principles is what really sets the new Turcon® Stepseal® V LM apart," says Henrik. "There's no other product like it on the market. The friction levels are heading in the direction of buffer seals or piston rings."

"Testing has been essential to give customers confidence in our solutions and to empirically prove the performance of our seals," In total, twenty-four systems were set up for testing, all representative of real conditions with appropriate supporting elements and secondary seals, with both Turcon® Stepseal® V LM seals and other types of primary seals, to compare the Turcon® Stepseal® V LM seals against and as a control.

With duplicate experiments set up concurrently to ensure repeatability, Henrik has confidence in the results. "We take testing very seriously. When downtime can be so expensive, trust in performance and reliability is vital. None of the systems tested showed any external leakage, but those incorporating the new seal generated up to 35% less friction than other primary seals, while also providing benefits to the rest of the system."

The new Turcon® Stepseal® V LM are manufactured within the same range as the Turcon® Stepseal® V and even include features that make installation easier and reduce the chance of damage during the process. "There's no other seal with the same response, robust dependability and simple hardware design that can give friction values this low," says Henrik.