Particle charging apparatus and method of charging particles

An aerosol particle charging apparatus for use in charging a stream of aerosol particles, the apparatus comprising:

• an elongated charger housing having a longitudinal axis extending between an inlet and an outlet defined therein, the inlet for receiving the stream of aerosol particles and the outlet for allowing the stream of aerosol particles to exit the charger housing;
• means for creating a confined electric field within the housing parallel to the longitudinal axis for use in directing a stream of unipolar ions to flow parallel to the axis of the charger housing;
• and
• means for creating a clean sheath between the stream of aerosol particles and the charger housing.

An aerosol particle charging apparatus for use in charging a stream of aerosol particles, the apparatus comprising:

• an elongated charger housing having a longitudinal axis extending between an inlet and an outlet defined therein, the inlet for receiving the stream of aerosol particles and the outlet for allowing the stream of aerosol particles to exit the charger housing, wherein the charger housing includes means for contracting the stream of aerosol particles proximate the outlet of the charger housing forcing the aerosol particles towards the longitudinal axis;
• means for creating a confined electric field within the housing parallel to the longitudinal axis for use in directing a stream of unipolar ions to flow parallel to the axis of the charger housing towards the outlet;
• and
• means for creating an outlet electric field in a direction generally opposite of the confined electric field such that charged particles of the stream of aerosol particles are forced towards the longitudinal axis.

An aerosol particle charging apparatus for use in charging a stream of aerosol particles, the apparatus comprising:

• an elongated charger housing having a longitudinal axis extending between an inlet and an outlet defined therein, the inlet for receiving the stream of aerosol particles and the outlet for allowing the stream of aerosol particles to exit the charger housing;
• a plurality of corona discharge elements positioned along the longitudinal axis for providing free electrons/ions into a charging zone defined by the charger housing;
• and
• an electrode configuration operable to create a confined uniform electric field within the housing parallel to the longitudinal axis for use in directing the free electrons/ions to flow parallel to the axis of the charger housing towards the outlet.