A filter frame, a filter cartridge, and an assembling method of the filter cartridge are provided. The method has the following steps. A filter core and a filter frame are prepared. The filter frame has a glue-cutting segment. Glue is coated around an outer wall of the filter core, and then the filter frame, which is mounted around the filter core, is pushed toward the glue to make the glue-cutting segment press the glue until the glue is cut into two parts. The inner glue part disposed between the filter core and the filter frame seals the filter cartridge. The outer glue part is disposed on an outer side of the filter frame, and is superfluous and removed. The glue-coating is combined with the mounting of the filter frame, thereby saving time and effort.

A filter element includes at least first and second opposing pleated media sections and at least first and second support structures supporting, absent an inner liner, the at least first and second media sections and being layered between the at least first and second media sections. In another embodiment, the filter element includes a continuous construction of pleated media forming the first and second opposing pleated media sections, in which the pleats have portions of differing lengths, and a support structure within the interior volume supporting the first and second media sections. The filter element can be in the form of two racetracks, a V-pack, or two V-packs. The racetracks can be polygon shaped.

An exemplary water circulation pump pre-filter unit (PFU) comprises a backwash pipe in fluid communication with an outer nozzle outside a screen cage and an inner nozzle within the screen cage. The PFU may simultaneously spray inside and outside the screen cage using an inner nozzle and an outer nozzle configured with an axial jet perpendicular to a plurality of radial jets. The inner nozzle may have a restriction chamber with diameter decreasing in flow direction to a full cone nozzle outlet, concentrating dual streams from a plurality of inlets swirled through a plurality of helical channels. Pairs of inner nozzles may be angled to each other, increasing the inner surface area cleaned. Exemplary implementations may simultaneously clean the screen cage bottom and top using the outer nozzle and inner nozzles in backwash mode and in a separate pre-filter mode ingest water through multiple filter pipe inlet apertures.

A filter cartridge for installation in a housing having a housing seat includes a filtration media compiled in a cylindrical pack having a radially outer face, a radially inner face defining a central cavity, a first axial end face, and a second axial end face. An end cap having an attachment portion is bonded and sealed to an axial end of the filtration media. A hub portion connects the attachment portion to a non-circular locking portion axially spaced from the attachment portion. The locking portion extends radially beyond the width of the hub portion and includes a sealing face having at least one annular sealing element for sealing against the housing seat.

A filter insert, a sample vial incorporating a filter insert, a method of using a sample vial containing a filter insert for chemical analysis, and a sample vial kit including a filter insert. The filter insert includes a cylindrical body having a proximal end, a protrusion extending radially from the proximal end of the cylindrical body and configured to set on the open end of a sample vial, a distal end, a cavity extending longitudinally through the cylindrical body from the proximal end to the distal end, and a filter assembly coupled with the distal end of the cylindrical body.

A filter insert, a sample vial incorporating a filter insert, a method of using a sample vial containing a filter insert for chemical analysis, and a sample vial kit including a filter insert. The filter insert includes a cylindrical body having a proximal end, a protrusion extending radially from the proximal end of the cylindrical body and configured to set on the open end of a sample vial, a distal end, a cavity extending longitudinally through the cylindrical body from the proximal end to the distal end, and a filter assembly coupled with the distal end of the cylindrical body.

A microplastic filter includes a housing including an inlet configured to receive water. The microplastic filter also includes a fine filter disposed to rotate within the housing and configured to filter residues from the water. The microplastic filter further includes an inside wiper disposed within the fine filter. The inside wiper includes a center post disposed along a rotational axis of the fine filter and a helical curved wall spirally extending between the center post and the fine filter, where the helical curved wall is configured to guide a portion of the water to backflow through the fine filter and force away at least some filtered residues from pores of the fine filter to prevent fouling or clogging of the fine filter. In addition, the microplastic filter includes an outside wiper spirally disposed around the fine filter and configured to dislodge other filtered residues from the fine filter as the fine filter rotates.