초록 ▼

A filter cartridge is provided which includes (a) a wound depth filter or a cylindrical seamless depth filter and (b) a pleated filter having a lower micron retention rating than the depth filter. The depth filter and pleated filter surround a central opening. The cartridge is sealed and an appropri

A filter cartridge is provided which includes (a) a wound depth filter or a cylindrical seamless depth filter and (b) a pleated filter having a lower micron retention rating than the depth filter. The depth filter and pleated filter surround a central opening. The cartridge is sealed and an appropriate inlet or outlet is provided in order to assure sequential fluid flow first through the depth filter and then through the pleated filter.

대표청구항 ▼

[ We claim:] [29.] A process for filtering particles from a liquid which comprises:introducing a liquid to be filtered into a filter assembly which includes a housing having an inlet for introducing liquid to be filtered and an outlet for filtered liquid,a filter cartridge including a first cylindri

[ We claim:] [29.] A process for filtering particles from a liquid which comprises:introducing a liquid to be filtered into a filter assembly which includes a housing having an inlet for introducing liquid to be filtered and an outlet for filtered liquid,a filter cartridge including a first cylindrical seamless depth filter and a pleated filter positioned within said housing, said pleated filter having a first percent retention efficiency of particles of a given sizesaid first cylindrical seamless depth filter formed of a plurality of filtration media formed from the thermoplastic fibers including a first of said filtration media having a lowest percent retention efficiency of said particles positioned adjacent said inlet and a second of said filtration media having a highest percent retention efficiency of said particles being positioned adjacent said pleated filter,said pleated filter being positioned adjacent said outlet,a screen supporting said pleated filter, said pleated fiber having a higher percent retention efficiency of said second of said filtration media,said first cylindrical seamless depth filter and said pleated filter surrounding a central opening which extends the length of said first cylindrical seamless depth filter and said pleated filter,said first cylindrical seamless depth filter and said pleated filter defining a first surface at one end which is sealed and said first cylindrical seamless depth filter and said pleated filter defining a second surface at an end opposite to said first end which is sealed with a second seal having a second opening that communicates with said central opening,said filter assembly having a pressure drop between said inlet and said outlet less than a predetermined pressure drop when challenged with water containing fine hard particles test dust at a given flow rate for a time period at least about 100% longer than a second filter element challenged with said water containing said fine hard particle test dust at said flow rate and formed from said first cylindrical seamless depth filter and a second cylindrical seamless depth filter having a percent retention efficiency of said particles substantially the same as said first percent retention efficiency of said particles of said pleated filter,passing said liquid to be filtered through said cylindrical seamless filter and said pleated filter,and removing filtered liquid from said outlet.