End of service life indicating systems for layered filter cartridges

摘要

Layered filtered cartridge systems with an End of Service Life Indicating system include a filter cartridge that includes filter media. The filter media includes a multi-layer construction, of a first sorbent layer, a second sorbent layer, and a sensing element adjacent to the first and second sorbent layers such that an indicating element of the sensing element is located at the interface between the first and second sorbent layers. The second sorbent layer has a higher adsorption capacity and/or higher adsorption rate than the first sorbent layer. The sensing element indicates the passage of an adsorption wavefront through the filter cartridge.