Patent ID: 8611066

Claim:
A bipolar charger for charging particles of a flow of aerosol, the bipolar charger comprising: a housing having a main chamber, a positive electrode chamber and a negative electrode chamber defined therein, the electrode chambers each being directly connected to the main chamber, the electrode chambers each having an inner surface; an inlet passage for providing a flow of aerosol into the main chamber, the inlet passage having an inner surface formed of an electrically conductive material; an outlet passage for charged aerosol to flow from the main chamber, the outlet passage having an inner surface formed of an electrically conductive material; a flow path for the aerosol being defined from the inlet passage, through the main chamber, and out of the outlet passage; a first ground electrode disposed in the positive electrode chamber; a positive electrode disposed in the positive electrode chamber and spaced from the first ground electrode; a second ground electrode disposed in the negative electrode chamber; a negative electrode disposed in the negative electrode chamber and spaced from the second ground electrode; a power supply interconnected with the first and second ground electrodes and the positive and negative electrodes; a first corona current being maintained between the positive electrode and the first ground electrode such that the positive electrode is at a high positive potential with respect to the first ground electrode and the positive electrode and the first ground electrode cooperate to create a cloud of positive ions; a second corona current being maintained between the negative electrode and the second ground electrode such that the negative electrode is at a high negative potential with respect to the second ground electrode and the negative electrode and the second ground electrode cooperate to create a cloud of negative ions; the first and second ground electrodes and the inner surfaces of the inlet and outlet passages being grounded relative to the positive and negative electrodes; and the positive electrode chamber and the negative electrode chamber each being in gaseous communication with the main chamber such that particles of an aerosol passing along the flow path through the main chamber interact with the ions, thereby creating a flow of aerosol with a steady-state electric charge distribution.