|
The diameter of
the shaft has
a tremendous impact on the performance of a shaft
seal. At a constant speed, as shaft size increases,
so does frictional drag on the seal’s lip.
This greater drag increases seal torque. Table
36 shows how seal torque increases
with increasing shaft
diameter. Keep in mind that the data reflected
in the following sections has been generated for
a specific set of parameters to demonstrate general
trends. Specific questions regarding suitability
for a given application may necessitate further
testing.
Greater
drag also increases power consumption. Table
37 shows how seal power consumption
increases with increasing shaft diameter. Increases
in both seal torque and seal power consumption
also increase a shaft seal’s underlip
temperature. Table 38 shows
how underlip temperature increases with increasing
shaft diameter at various shaft
speeds. Pump rate also increases as
both shaft and seal size increase. Table
39 shows how pump rate increases
with increasing shaft diameter at various shaft
speeds.
Because
increases in shaft diameter have such a profound
impact on seal operating characteristics, the seal’s
cross-section is typically increased (as is lip-to-shaft interference level)
as shaft size increases in order to ensure that seal
life remains constant. Table 40 shows
how seal life can vary with increasing shaft diameter.
THE
SHAFT MAIN PAGE
|
