Pedestals and housings for fluid film bearings using oil lubricants generally have seals to control the lubricant flow and prevent leakage. In electrical motors, such leakage can contaminate the electrical windings. In some facilities leakage can lead to environmental concerns. These seals will have slightly more clearance than the bearings to avoid rubs.
We provide new and refurbished oil seals, whether smooth bore, labyrinth, or floating ring, for a variety of bearing and pedestal styles. Although we are completely capable of performing babbitt welding services, when refurbishing these seals we prefer to re-cast them by either of our proven centrifugal or static casting methods to avoid the risk inherent in local babbitt welding of breaking the underlying existing babbitt bond, a bond achieved by another source and of unknown strength to Pioneer.
We ourselves cannot test the strength of our own babbitt bond in a particular part without a destructive test; however, we do conduct on-going internal quality assurance destructive tests on sacrificial test pieces to maintain the integrity of our process and our required standard for bond strength. In handling an existing seals babbitted by some unknown other company, however, we have no idea of the integrity of the process employed to obtain the bonds in the parts, thus we prefer to completely re-cast these seals. Contact us for a thorough explanation.
Many tilting-pad journal bearing designs use axial end seals to control the volume of oil flow through the bearing. The seal clearance sets the oil flow, which controls the operating temperatures within the bearing. Again, we prefer to babbitt these seals by completely re-casting them, either by our proven centrifugal or static methods, to avoid the risk inherent in local babbitt welding of breaking the underlying existing babbitt bond.
Large electrical generators rotate in hydrogen to reduce friction losses. Oil flooded, floating ring seals are a part of the pressure boundary to prevent hydrogen leakage. These hydrogen seals, often babbitted and sometimes referred to as “hydrogen (H2) gland seals”, have very precise geometry to maintain proper sealing over a range of operating conditions.
We have more than 35 years of experience in manufacturing new seals for our OEM customers and re-casting worn seals, where feasible, for end users operating a variety of generator designs.
The bracket for hydrogen gland seals on the ends of large electrical generators requires precision machining to achieve the fits and clearances required for reliable sealing of the hydrogen within the generator. With aging and maintenance, the geometry of these brackets may have sufficiently changed to result in excessive leakage or premature seal damage. Pioneer can assist customers in restoring the original fit dimensions, or in adapting a bracket to accommodate journal damage.
By teaming our manufacturing and repair services with a first-rate bearing engineering department, we can help our customers operate turbines and generators more efficiently and reliably over an extended life.