Page 193 - Improving Machinery Reliability

164 Improving Machinery Reliability

Figure 3-52. Oil spray generated by the flinger disc will easily flow through this face-to-
face oriented bearing set. (Courtesy Ochsner Kreiselpumpen Co. Linz, Austria.)

Figure 3-56 shows how the oil delivery capability of oil rings varies with shaft
speed. Grooved rings are demonstrably superior to the traditional flat rings and
should be applied whenever the less vulnerable flinger disk, shown in Figures 3-50
and 3-55, is not available.
The Goulds Pump Company has experimented with different executions and
found that keeping the oil level below the rotating elements results in lower bearing
temperatures than would be achieved if lube oil were to reach to the center of the
lowermost ball. Goulds explained that their optimum design, Figure 3-59, evolved
from the one shown in Figure 3-58, which incorporated a cupped oil flinger design.
The throw-off action of the cupped disks did not differ significantly from that
obtainable with plain disks. Moreover, using two separate disks occasionally resulted
in incorrect installation by inexperienced repair shops. The manufacturer corrected
this situation by using the single spool or spacer piece in Figure 3-59 for oil ring
containment,
Goulds established a satisfactory working window for the design using IS0 Grade
68 lube oils and shaft diameters in the 2.5-in. range. Adequate oil flow existed with