| 摘要 |
<p>A filter apparatus including a filter housing having an inlet and an outlet and a filter device locatable therebetween; said filter device comprising a filter medium for gas of dielectric and polarisable material, an electrically conductive screen, mesh or like potential means connectable to a supply of high voltage power and provided only to abut said filter medium such that when said electrically conductive potential means is subject to a high voltage so that the filter medium is polarised and either nothing apart from air or a support or retention means of dielectric material is on a side of said filter medium immediately opposite to said charge applying means and no charge applying means are located upstream of said potential means.</p> |
