A ballast water production method is provided. The method includes a filtering step that passes raw water supplied into a housing through a filter from a primary side that is upstream of the filter to a secondary side that is downstream of the filter; a volume-increasing step after the filtering step that increases a volume of water present in a space on the secondary side of the housing while the supply of the raw water into the housing is stopped; a pressurizing step after the volume-increasing step that pressurizes an inside of the housing from the secondary side while the supply of the raw water into the housing is stopped; and a rinsing step after the pressurizing step that passes a fluid through the filter from the secondary side to the primary side while the supply of the raw water into the housing is stopped.

A filter element, in particular for treating fluids in the form of diesel fuel, has a filter medium (14) through which the fluid can flow. The filter medium (14) contains at least one active substance having antimicrobial properties.

A filter includes a plurality of annular filter elements arranged in axially staggered relation. An axial flow path includes a plurality of flow path segments, some being filtered by a respective filter element, and others bypassing a respective filter element. Various combinations are provided.

A separation component for a filter element has a web-shaped support body with a top rim and a bottom rim. A web-shaped separator body covers a side face of the support body completely or partially. Support body and separator body are wound to a spiral shape with axially successive turns. The support body has a connecting fold at the top rim and at the bottom rim, respectively. The connecting folds engage each other in the axially successive turns of the spiral shape. The separation component can be manufactured by placing a web-shaped separator body onto a web-shaped support body and by winding support body and separator body to a spiral shape. During winding, a connecting fold at a top rim of a turn of the spiral shape and a connecting fold at a bottom rim of an axially successive turn are brought into engagement with each other.

A long-life in filters is required as filter members for slurry liquid having high-viscosity and high-solid-content ratio. It is provided to solve the problem, the filter element for filtering slurry liquid, wherein nets and non-woven fabrics are alternately layered, wherein each of the nets has first fibers parallelly extending in one direction and second fibers parallelly extending in a direction angled to the one direction and contacting sides of the first fibers, wherein the first and second fibers forms mesh-pores at portions surrounded by the first and second fibers, wherein each of the non-woven fabrics has protrusions on surfaces of the each of the non-woven fabrics in a thickness-direction, the protrusions formed to repeatedly come out on the surfaces of the each of the non-woven fabrics in a surface-direction of the each of the non-woven fabrics.