US Patent 10322811 Air purification system and method of assembling

A filter assembly including a plurality of filter modules, wherein each filter module in the plurality of filter modules includes a frame, a filtration element coupled within the frame, and at least one mating feature. The at least one mating feature of each filter module is configured for selective engagement with the at least one mating feature of another filter module such that the plurality of filter modules are coupled together in a serial arrangement.