Air treatment apparatus

An evaporator assembly 1200 for use in an evaporative humidifier comprises an arrangement of porous material and an evaporator frame that supports the porous material. The evaporator frame comprises an outer grille 1202 surrounding an outer surface of the porous material and may comprise an inner grille 1203 extending over an inner surface of the porous material. The arrangement of porous material may be multi-layered. The arrangement may comprise a sheet of porous material formed into a spiral or roll to have multiple overlapping layers or may comprise multiple pieces of porous material that form separate tubes disposed concentrically. The evaporator frame may comprise first and second end caps 1204a, 1204b. The arrangement of porous material may comprise first and second sections of porous material (1201a, 1201b, Fig.34). The frame may have a shelf (1205, Fig.34) and may comprise two inlet funnels (1206a, 1206b, Fig.34) that each project from an outer surface of the outer grille and receive and convey water from outside of the evaporator frame onto a corresponding surface of a two-sided trough provided by the shelf. An air treatment apparatus comprises an evaporative humidifier comprising the evaporator assembly.