Seals
Six seal problems from mines and cement plants, and what fixed them
Quick answer
Hot strut wipers, huge shafts, mill trunnions, haul truck hubs, conveyor drives and lift cylinders: the problem, the cause and the design change that helped.
Why these stories matter
They come from the harshest equipment in the chain. The pattern is the same each time: find the main exposure, change the seal design or material to match it, and make the new seal easier to fit.
The six problems
| Application | Problem | What helped |
|---|---|---|
| Hauler strut cylinders near molten slag | Ambient temperature above 120 °C ruined the split brass wiper held by a wave spring, and dirt got in | A one-piece high-performance polymer wiper with the right profile: less ingress, simpler fitting, much longer life |
| Large-diameter shafts and gearboxes | Replacing a seal meant removing the drive and coupling, with long downtime | Split seals and polyurethane seals welded on site keep the full sealing capacity without stripping the machine |
| Ball and SAG mill trunnions | The seal must hold oil in, keep slurry out and survive wash-down | A double or triple lip split seal with a purge feature removes contaminants and reduces wear on the trunnion surface |
| Haul truck suspension and driveline | Slow, full-stroke movement when loaded; short fast strokes when empty; heavy contamination | Self-lubricating polyurethane rod seals, metal face seals and cassette seals; metal-cased seals with two springs on wheel hub motors |
| Conveyor pulleys and drives | Abrasive dust and wear shorten seal life | Abrasion-resistant polyurethane with extra V-rings, or standard radial seals with V-rings on gearboxes |
| Lift and tilt cylinders on mobile fleets | Extreme climates from freezing to very humid, plus dirt | Material and profile matched to the climate, plus failure analysis of the damaged seals and a tailored redesign |
Lessons that repeat
- Start with the real cause: heat, dirt, speed, shock or access
- Often the fix is a better wiper or an extra V-ring, not a new seal type
- Fitting time matters: a seal that takes less time to change gets changed on schedule
- Always keep a failed seal for analysis: the damage pattern tells you what to change
Takeaway. The best seal fixes change one thing that matches the cause: a material, a profile, an extra guard or a split design. Fix the cause, then make the seal quicker to fit.
Put it to work in the tool