A filter assembly comprises a housing defining an internal volume. A housing second end of the housing defines at least one female thread. A bowl is positioned at the housing second end The bowl comprises at least one bowl male thread structured to engage the at least one female thread of the housing so as to be coupled thereto.

A direct water purifier includes a first filter for filtering water introduced through a first flow path; a second filter for receiving the water supplied from the first filter through a second flow path and filtering the same; a first valve disposed in the second flow path to control water flow; a pump disposed in the second flow path to supply water having a predetermined hydraulic pressure or higher to the second filter; a third filter for receiving the water supplied from the second filter through a third flow path and filtering the same; a heating part for receiving the water supplied from the third filter and heating the same to a predetermined temperature; and a flushing valve disposed in a flushing flow path through which concentrated water is discharged from the second filter, wherein the flushing valve is opened during operation of the heating part.

A direct water purifier includes a first filter for filtering water introduced through a first flow path; a second filter for receiving the water supplied from the first filter through a second flow path and filtering the same; a first valve disposed in the second flow path to control water flow; a pump disposed in the second flow path to supply water having a predetermined hydraulic pressure or higher to the second filter; a third filter for receiving the water supplied from the second filter through a third flow path and filtering the same; a heating part for receiving the water supplied from the third filter and heating the same to a predetermined temperature; and a flushing valve disposed in a flushing flow path through which concentrated water is discharged from the second filter, wherein the flushing valve is opened during operation of the heating part.

In one embodiment, after a new filter unit is installed in a treatment liquid supply apparatus, there is performed, before a solvent-containing treatment liquid is passed through the filter unit, a step of soaking the filter unit with a solvent for pretreatment and then discharging therefrom the solvent. The solubility of a material, constituting a filter part of the filter unit, to the solvent is greater than the solubility of the material to the treatment liquid. This step makes it possible to remove a component, which may elute from the filter part into the treatment liquid to produce foreign matters (particles), before treatment liquid is passed through the filter unit.

In one embodiment, after a new filter unit is installed in a treatment liquid supply apparatus, there is performed, before a solvent-containing treatment liquid is passed through the filter unit, a step of soaking the filter unit with a solvent for pretreatment and then discharging therefrom the solvent. The solubility of a material, constituting a filter part of the filter unit, to the solvent is greater than the solubility of the material to the treatment liquid. This step makes it possible to remove a component, which may elute from the filter part into the treatment liquid to produce foreign matters (particles), before treatment liquid is passed through the filter unit.

Disclosed is a filtration device for a liquid, including: at least two superimposed layers of filter media having weld lines creating strips between them, the layers of filter media having weld lines being superimposed such that the weld lines of one layer form, with the weld lines of the other layer, a mesh structure when viewed at an angle normal to the layers of filter media; a first external face and a second external face each being produced at least locally from a water-permeable material, the layers of filter media being positioned between the external faces; and an intake connector used for drawing liquid in through the filtration device.

Disclosed is a filtration device for a liquid, including: at least two superimposed layers of filter media having weld lines creating strips between them, the layers of filter media having weld lines being superimposed such that the weld lines of one layer form, with the weld lines of the other layer, a mesh structure when viewed at an angle normal to the layers of filter media; a first external face and a second external face each being produced at least locally from a water-permeable material, the layers of filter media being positioned between the external faces; and an intake connector used for drawing liquid in through the filtration device.

A filter system for filtering a fluid is provided with a filter housing that has a housing top part and a housing bottom part arranged along a housing axis of the filter housing. An inlet socket is arranged at the housing top part for supplying a fluid to be filtered. An outlet socket is arranged at the housing top part for discharging the fluid. A filter element is provided with a filter bellows arranged about a longitudinal axis of the filter element. The filter element, installed inside the filter housing, fluidically separates a raw fluid side from a clean fluid side. A central element is attached to the filter housing and extends along the housing axis. The central element is separate from the filter element and projects into an interior of the filter element. A strainer filter is arranged at the central element.

A filter system for filtering a fluid is provided with a filter housing that has a housing top part and a housing bottom part arranged along a housing axis of the filter housing. An inlet socket is arranged at the housing top part for supplying a fluid to be filtered. An outlet socket is arranged at the housing top part for discharging the fluid. A filter element is provided with a filter bellows arranged about a longitudinal axis of the filter element. The filter element, installed inside the filter housing, fluidically separates a raw fluid side from a clean fluid side. A central element is attached to the filter housing and extends along the housing axis. The central element is separate from the filter element and projects into an interior of the filter element. A strainer filter is arranged at the central element.

A functional component of a fluid filter is provided with at least one component connection element of a mechanical connection device, wherein the at least one component connection element can be connected releasably to at least one corresponding housing connection element of the mechanical connection device by a rotation/push-in movement about a virtual axis. The at least one corresponding housing connection element is provided at a filter housing of the fluid filter. The at least one component connection element has at least one securing contour that interacts with at least one joining element to secure the mechanical connection device and prevent an accidental release of the mechanical connection device, wherein the at least one joining element is connected to the filter housing after the functional component has been mounted at the filter housing.