초록 ▼

A filter arrangement is provided. The filter arrangement generally includes an air filter having an upstream surface with a prefilter positioned thereon. The prefilter preferably includes at least two layers of depth media. In preferred systems, the prefilter includes two layers of depth media secur

A filter arrangement is provided. The filter arrangement generally includes an air filter having an upstream surface with a prefilter positioned thereon. The prefilter preferably includes at least two layers of depth media. In preferred systems, the prefilter includes two layers of depth media secured to one another by stitching. In certain preferred arrangements disclosed, the prefilter includes an upstream layer of fibrous depth media and a downstream layer of foam depth media, with the two layers stitched to one another along peripheral edges. The invention also concerns provision of prefilters, and also air filter arrangements which include housings having air filters with prefilters according to the present invention operably positioned therein. Methods of construction and use are also provided.

대표청구항 ▼

[ What is claimed is:] [1.] A filter arrangement comprising:(a) an inner air filter having:(i) first and second end caps;(ii) an inner and an outer liner extending between the first and second end caps; said outer liner having a first open surface area;(iii) cylindrical filter media between said inn

[ What is claimed is:] [1.] A filter arrangement comprising:(a) an inner air filter having:(i) first and second end caps;(ii) an inner and an outer liner extending between the first and second end caps; said outer liner having a first open surface area;(iii) cylindrical filter media between said inner and outer liners and potted within said first and second end caps;(b) a removable and replaceable filter circumscribing said inner air filter and covering said outer liner; said removable and replaceable filter covering at least 90% of said first open surface area of said outer liner;(i) said removable and replaceable filter comprising a ring construction of filter material including first and second layers of filter media secured together by stitching;(A) said ring construction having first and second, opposite circular rims;(B) said stitching including at least a first set of stitches along said first circular rim, and a second set of stitches along said second circular rim;(ii) said first layer comprising an outer layer generally surrounding said second layer;(A) said first layer being upstream of said second layer;(iii) said first layer of filter media comprising non-woven fibrous depth media; and(iv) said second layer of filter media comprising a layer of foam media including an open cell polyurethane foam having a cell density of 30 to 80 pores per inch.