Graded density, high porosity, SPUNFLOW QN filter elements are manufactured from thermally bonded polypropylene microfibres. Offering high throughputs, low pressure loss, high dirt holding capacity and long onstream life, the bonded fibre construction minimises any possibility of fibre migration and is rugged enough to resist particle shedding, even under pulse conditions. The SPUNFLOW construction process consists of controlled fibre diameter throughout the extrusion process and thermally bonds these micro-fibres into a complex filter matrix. These interlinked graded density layers offer maximum support and maximum void volume resulting in true depth filtration.