There are a number of applications today where the pumping of abrasive
slurries is necessary. The pumping mechanisms, though, can be complex,
employing multiple transfer cylinders and movable pipes. These designs
have their problems, specifically wear between poorly sealing surfaces.
To reduce this problem, seals are provided that have multiple wear
surfaces which include harder tiles secured over a softer core to benefit
from the relative hardness or flexibility of each of the respective
materials.