The Hunger wiper ring type AI has the function to keep
out extremely fine dust, metal particles, grains of sand
etc. such that the bearing elements and seals behind
it are not subjected to premature wear as a result of
contaminant ingress.
The AI wiper can be used with mineral oils and many
other types of hydraulic fluid.
Special versions are available for use at high ambient
temperatures.
Care must be taken to ensure that there is no pressure
build-up, including grease lubricant pressure, on the
inside of the wiper.