A filter assembly is provided that includes an immobilized base material
in combination with a slow release mechanism for introducing an additive
base material into a lubrication fluid flowing through the filter
assembly. The introduced base material is a weaker base material than the
base material of the immobilized base material. The combination of the
immobilized base material and the additive base material provides a
system that would work to neutralize acids for all lube formulations
commonly used in the field. As a result, oil drain intervals can be
extended.