Creating a Perfect Oil Seal

A good oil or radial shaft seal is designed to either keep oils or other fluids from leaking out of a mechanical component or to keep contaminants from finding their way in, and many times both.

Pumps, mixers, motors, turbines and gear boxes in a variety of industries are susceptible to problems that can be caused by an inadequate sealing system.

To create the perfect oil seal for your equipment, an understanding and an anticipation of the potential damaging factors for your rotary seal are essential.

With the failure of an oil seal, the liquid or gases you are trying to protect could be affected by:

• An increase of oxidation
• A decrease in viscosity
• Unwanted aeration
• Chemical and physical changes, such as the depletion of additives, increased TAN, sludge or varnish

Your equipment can also be impaired by a failed oil seal by creating:

• Improper film thickness on the shaft due to excessive lip wear
• Corrosion
• Cavities or pits

Determining the best oil seal for your application needs requires a quick review of all installation parameters and operating conditions that will affect the seal including:

• Shaft finish
• Shaft speed
• Internal pressure
• Operating temperature
• Fluid compatibility

Leakage can occur at both the seal inside diameter or housing bore diameter.

Static leakage can occur at either.   Leakage occurring at the press-fit at the seal’s outside diameter (OD) can be a result of:

• the housing bore being too rough
• damage to the OD during installation (70% of all seal failures are due to cocking during installation)
• inadequate press fit, due to out-of-range bore tolerance, incorrect seal OD for the bore diameter, or a severely rusted or pitted bore

Leakage at the sealing lip can be caused by damage during installation, shaft condition, or poor internal lubricant draining.

Dynamic leakage normally occurs only at the sealing lip, with damage to the radial shaft seal itself, from poor seal fit, or from operating conditions in excess of those recommended by the manufacturer.

The Seal Specialists at Web Seal can recommend the best sealing solutions for your needs.  We offer more than 700 English and metric Parker and Clipper oil shaft seals for all applications, in sizes ranging from .250” up to 72”.  Traditional metal canned and rubber-coated designs are available along with one-piece bonded seals (typically PTFE-to-elastomer).

We can also help you create any specialty seal design for your specific equipment needs.

Click here for design assistance or to request a quote.