A barrier filter stage comprising a combination v-pack air filter cartridge positioned in a barrier filter housing including a scavenge arrangement wherein: (a) the v-pack air filter cartridge comprises: (i) first and second panel sections (55; 56) arranged as sides of a v-pack configuration with a narrow end and a wide end; (ii) a closed end piece positioned over the narrow end of the v-pack configuration; (iii) an open end piece positioned over the wide end of the v-pack configuration; and, (b) a scavenge arrangement positioned in a bottom of the housing with the v-pack air filter cartridge positioned thereon: (i) the housing bottom having a first end and a second end separated by a distance Y; the v-pack filter cartridge being positioned with the open end piece positioned adjacent to the housing bottom first end; (ii) the scavenge arrangement comprising first and second scavenge aperture arrangements (101; 102); the v-pack air filter cartridge being positioned on the housing bottom at a location between the first and second scavenge aperture arrangements (101; 102); the first scavenge aperture arrangement having a first total open area X 1 and being configured such that at least 90% of the open area X 1 is located within a distance of 50% Y across the housing bottom from the housing bottom first end toward the housing bottom second end; and, the second scavenge aperture arrangement having a second total open area X 2 and being configured such that at least 90% of the open area X 2 is located within a distance of 50% Y across the housing bottom from the housing bottom first end toward the housing bottom second end; (a) a blower takeoff located closer to the housing bottom first end than to the housing bottom second end. (a) the v-pack air filter cartridge comprises: (i) first and second panel sections (55; 56) arranged as sides of a v-pack configuration with a narrow end and a wide end; (ii) a closed end piece positioned over the narrow end of the v-pack configuration; (iii) an open end piece positioned over the wide end of the v-pack configuration; and, (i) first and second panel sections (55; 56) arranged as sides of a v-pack configuration with a narrow end and a wide end; (ii) a closed end piece positioned over the narrow end of the v-pack configuration; (iii) an open end piece positioned over the wide end of the v-pack configuration; and, (b) a scavenge arrangement positioned in a bottom of the housing with the v-pack air filter cartridge positioned thereon: (i) the housing bottom having a first end and a second end separated by a distance Y; the v-pack filter cartridge being positioned with the open end piece positioned adjacent to the housing bottom first end; (ii) the scavenge arrangement comprising first and second scavenge aperture arrangements (101; 102); the v-pack air filter cartridge being positioned on the housing bottom at a location between the first and second scavenge aperture arrangements (101; 102); the first scavenge aperture arrangement having a first total open area X 1 and being configured such that at least 90% of the open area X 1 is located within a distance of 50% Y across the housing bottom from the housing bottom first end toward the housing bottom second end; and, the second scavenge aperture arrangement having a second total open area X 2 and being configured such that at least 90% of the open area X 2 is located within a distance of 50% Y across the housing bottom from the housing bottom first end toward the housing bottom second end; (i) the housing bottom having a first end and a second end separated by a distance Y; the v-pack filter cartridge being positioned with the open end piece positioned adjacent to the housing bottom first end; the v-pack filter cartridge being positioned with the open end piece positioned adjacent to the housing bottom first end; (ii) the scavenge arrangement comprising first and second scavenge aperture arrangements (101; 102); the v-pack air filter cartridge being positioned on the housing bottom at a location between the first and second scavenge aperture arrangements (101; 102); the first scavenge aperture arrangement having a first total open area X 1 and being configured such that at least 90% of the open area X 1 is located within a distance of 50% Y across the housing bottom from the housing bottom first end toward the housing bottom second end; and, the second scavenge aperture arrangement having a second total open area X 2 and being configured such that at least 90% of the open area X 2 is located within a distance of 50% Y across the housing bottom from the housing bottom first end toward the housing bottom second end; the v-pack air filter cartridge being positioned on the housing bottom at a location between the first and second scavenge aperture arrangements (101; 102); the first scavenge aperture arrangement having a first total open area X 1 and being configured such that at least 90% of the open area X 1 is located within a distance of 50% Y across the housing bottom from the housing bottom first end toward the housing bottom second end; and, the second scavenge aperture arrangement having a second total open area X 2 and being configured such that at least 90% of the open area X 2 is located within a distance of 50% Y across the housing bottom from the housing bottom first end toward the housing bottom second end; (a) a blower takeoff located closer to the housing bottom first end than to the housing bottom second end.