A massive reduction of dust particle adhesion in a cyclone by the introduction of a wedge

Particle adhesion in a cyclone, such as a cyclonic vacuum cleaner, can significantly reduce its efficiency. An investigation is presented here on the particle adhesion in a cyclone from a vacuum cleaner that consists of a primary separation stage (a cylindrical chamber) and a secondary separation stage (14 cyclones). The flow direction in the primary separation stage was modified by the use of a wedge of 40 mm × 40 mm × 6 mm at the inlet of the primary separation stage, which affected the particle trajectory in the primary separation stage and the particle inlet position in the cyclone while keeping the air flow direction and velocity (without particles being loaded), the Hamaker constant, particle size and the particle charge unaffected. The particle inlet position in the cyclone was varied from the lower portion (without wedge) to the upper portion (with wedge). Without the wedge, a spiral pattern of particle (plaster particles, average size 1.13 μm) adhesion onto the inner wall of the cyclone was found and a thicker deposited layer of particles at the cyclone tip region was observed. With the introduction of the wedge, the spiral particle adhesion pattern was not observed and a reduction of particle adhered to the inner wall by up to 94% was achieved, although there was an increase in the amount of particles entering the cyclone. This demonstrates almost a complete elimination of particle adhesion onto the cyclone wall, without compromising separation efficiencies.