Disclosed herein is a filter having a housing having first and second end surfaces and interior and exterior surfaces, a membrane disposed within the tubular housing, a first end cap sealed to the first end surface of the tubular housing and the first end surface of the membrane; a second end cap sealed to the second end surface of the tubular housing and the second end surface of the membrane; and a fluid channel formed in the interior surface of the housing in a helical pattern. The helical pattern has a helical pitch in an axial direction of the housing of less than or equal to about 60 mm.

Disclosed are filter systems and methods for swimming pools and spas for leaves and other larger debris. The disclosed filtering devices may be provided in-line with a pool cleaning or filtering system such that filtering devices pre-filter the larger debris before the pool cleaning or filtering system filters smaller debris. In some cases, the filtering devices provide an airtight seal that is easy for a user to open or close as desired. In some cases, the disclosed filtering devices include a filter between an inlet and an outlet that are parallel to and offset from a center axis of the filter. In some cases, the filtering devices are configured to generate horizontal cyclonic flow of water.

Fluid filtration devices and methods of filtering fluids are described. The devices generally include a housing, a hollow filter assembly, a rotating cleaning assembly and a device to measure the accumulation of solids in the filter housing. In some embodiments the accumulation of solids is measured by measuring the torque required to rotate the cleaning assembly. Torque may be measured directly, such as with a torque sensor, or indirectly, such as by measuring the current used by an electric motor to drive rotation of the cleaning assembly. In some embodiments a purge valve is opened to remove accumulated solids from the housing when a certain level of solids accumulation is detected.

A strainer assembly for a pressurized fluid system having a pressure vessel with an oppositely directed inlet and outlet located thereon at a common elevation and a drain port in the bottom. A tubular diverter is disposed in the pressure vessel with an annular member sealed about the lower end of the diverter at an angle to the diverter axis and having its outer periphery sealed about the pressure vessel with one side of the member above the inlet and the opposite side below the outlet and isolating the inlet from the outlet. A cover is releasably disposed in fluid sealing engagement over the upper end of the diverter and includes a cylindrical strainer retained in the cover by a support ring having outwardly extending portions connected to the cover; and, the support ring is sealed over the upper end of the diverter. Fluid from the inlet flows upwardly through the diverter through the support ring and into the strainer. Flow emanating from the strainer flows downwardly around the diverter to the outlet. Large debris settles downwardly through the diverter to the bottom of the pressure vessel and is removed by selectively opening the drain port.

Provided are an apparatus for filtering a fluid, the apparatus including a first flow channel and a second flow channel which are connected to each other in a fluid communicable manner via a filtration medium, and a method of isolating particles using the apparatus.