NONWOVEN FILTER MEDIA

Nonwoven webs and filter media are described herein having a region that has a gradient wherein the concentration of a fiber or a property varies from one side of the region to the other side of the region. In one embodiment， an apparatus (100) includes a mixing partition (110) downstream from one or more sources of a first and second flow stream that each includes a fiber. The mixing partition (110) defines one or more openings (112) that permit fluid communication between the two flow streams (104， 108). The apparatus also includes a receiving region (114) situated downstream from the one or more sources (102， 106) and designed to receive at least a combined flow stream and form a nonwoven web by collecting fiber from the combined flow stream. In one embodiment， a method includes collecting fiber on a receiving region (114) situated proximal and downstream to the source or sources of the flow stream (102， 106)， where the receiving region (114) designed to receive the flow stream dispensed from the source and form a wet layer by collecting the fiber. Nonwoven webs and filter media are described herein having a region that has a gradient wherein the concentration of a fiber or a property varies from one side of the region to the other side of the region. In one embodiment， an apparatus includes a mixing partition downstream from one or more sources of a first and second flow stream that each includes a fiber. The mixing partition defines one or more openings that permit fluid communication between the two flow streams. The apparatus also includes a receiving region situated downstream from the one or more sources and designed to receive at least a combined flow stream and form a nonwoven web by collecting fiber from the combined flow stream. In one embodiment， a method includes collecting fiber on a receiving region situated proximal and downstream to the source or sources of the flow stream， where the receiving region designed to receive the flow stream dispensed from the source and form a wet layer by collecting the fiber.