This burner is disposed at the upstream side of a DPF and raises the temperature of exhaust by combusting an air-fuel mixture of air and fuel in a combustion region within a flame holder. The process includes the steps of dispersing polymeric binder materials and optional additives in an organic solvent to form an organic phase. Located parallel to the first axle is a second axle located between the circular plates or two lateral extending arms. Said core can move with an operating clearance relative to said outer cage and cannot be removed from said outer cage and can move with an operating clearance relative to said inner cage, and cannot be removed from said inner cage.