Gas streams often carry particulate material therein. In many instances it is desirable to remove some or all of the particulate material from the gas flow stream. For example, air intake streams to engines for motorized vehicles or power generation equipment often include particulate material therein. The particulate material, should it reach the internal workings of the mechanisms involved, can cause substantial damage. It is therefore preferred, for such systems, to remove the particulate material from the gas flow upstream of the engine or other equipment involved. A variety of air cleaner arrangements have been developed for particulate removal.
There has been a general trend for the utilization of air cleaner arrangements that utilize, as a media pack, z-filter media constructions. In general z-filter media constructions can be characterized as comprising a fluted sheet secured to a facing sheet, formed into a media pack configuration. Examples of z-filter arrangements are described in PCT Publication WO 97/40918, published Nov. 6, 1997; U.S. Pat. Nos. 6,190,432 and 6,350,291; PCT application US 04/07927, filed Mar. 17, 2004; U.S. Provisional application 60/532,783, filed Dec. 22, 2003; PCT Publication 03/095068, published Nov. 20, 2003; PCT publication WO 04/007054, published Jan. 22, 2004; PCT publication WO 03/084641, published Oct. 16, 2003; and, U.S. Provisional Application 60/543,804, filed Feb. 11, 2004; the complete disclosures of each of these cited references being incorporated herein by reference.
In general, improvements have been sought.