the filter medium 82 the cleaned air then leaves the top of the electrostatic filter 70 and enters the exhaust passage 100 which directs air downwardly through the centre of the separating apparatus 6 to the exit port 96 which is located on the lower end of the separating apparatus 6 in the embodiment shown in fig6 a and 6 b the further cleaned dust laden air passes out of the vortex finders 66 and enters the plenum 98 the air passes through the plenum 98 and enters the top of the electrostatic filter 70 the air then travels past the corona discharge device formed from the corona discharge electrode 84 and the electrodes of low curvature 86 such that any dust particles remaining in the further cleaned dust laden air become charged the further cleaned dust laden air containing the charged dust then travels downwardly through the filter medium 82 a potential difference is generated across the filter medium 82 causing the charged dust particles to be attracted to respective positive and negative ends of the filter medium 82 thus trapping them within the filter medium 82 the cleaned air then leaves the lower end of the electrostatic filter 70 and exhausts the separating apparatus 6 via the exit port 96 located on the lower end of the separating apparatus 6 in the embodiment shown in fig7 the further cleaned dust laden air passes out of the vortex finders 66.