Filter change indicator

摘要

A filter change indicator includes two indicators visible through a window. The first indicator is disposed in the viewing window in a fixed position. The second indicator covers the first indicator in a first position and is moveable relative to the first indicator to a second position revealing the first indicator. The filter change indicator also includes a spring and flexible diaphragm arranged such that changes in the pressure of a fluid system moves the second indicator to expose the first indicator to provide a visual indication of filter occlusion.