At a major refinery, vertical molten sulfur pumps were fitted with
nickel-chromium (Ni-Cr) bearings to handle the high-temperature
environment. To avoid seizing and galling, the line shaft and volute
bearings were fit with 0.020 – 0.025” running clearance. However, the
pumps were experiencing high vibration, approaching 1.0 inches/second
peak. When they disassembled the pump, the bearing clearances had
opened up to 0.030 – 0.034”.
The customer contacted one of our engineers and asked:
"How well do the
GRAPHALLOY sleeve bearings fare in liquid sulfur
service? There are eight vertical column pumps in our sulfur pit..four of
which are quite the trouble-makers when it comes to high vibration.
Vibration data usually indicates some sort of imbalance. Any feedback is
greatly appreciated as this definitely sounds like a product worth
pursuing to "dampen" the current vibration in these pumps."
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