Abstract: An electrostatic air cleaner is disclosed for use in removing particulate matter from moving streams of air. A high voltage ionizer is used as a corona source to ionize the particulate matter as it approaches the air filter portion of the electrostatic air cleaner. The air filter uses reticulated polyether foam filter media for collecting the particulate matter, and the filter media is non-deliquescent, thus preventing the high-voltage electric field from being dissipated by imbedded water vapor, which is the cause of filter inefficiency in the prior art. In one embodiment, the air filter uses strips of conductive material raised to a very high DC voltage interleaved between strips of conductive material held to ground potential, and these strips are oriented so as to be parallel to the direction of the air flow through the air filter's foam filter media, thereby creating an electric field that is perpendicular to the direction of air flow.

Abstract: An electrostatic air cleaner is disclosed along with a method for removing particulate matter from moving streams of air. A high voltage ionizer is used as a corona source to ionize the particulate matter as it approaches the air filter portion of the electrostatic air cleaner. The air filter uses a pair of reticulated polyether foam filters for collecting the particulate matter. The foam filters are separated by a thin, grid-like layer of semiconductive material (carbon-impregnated polycarbonate) which is raised to a very high DC voltage. The foam filters are also surrounded by thin, grid-like layers of electrically conductive material which are held at ground potential, thus creating a high-voltage electric field through each of the foam filters. The polyether foam filter media is non-deliquescent, thus preventing the high-voltage electric field from being dissipated by such imbedded water vapor, which is the cause of filter inefficiency in the prior art.

Abstract: A conventional HEPA (high efficiency particulate air) filter is provided with a ionizer at its air inlet face to enhance its efficiency. The filter comprises a non-conductive fibrous filter medium sheet formed in a zig-zag or accordian fold. Within each fold of the filter medium is there located a conductive spacer so that the accordian folds are supported and substantially evenly spaced throughout the filter. By virtue of the accordian fold of the filter medium sheet, a series of spacers, forming a first set thereof, each has one of its longitudinal edges exposed at the air inlet face of the filter and the other of its longitudinal edges covered at the air discharge face of the filter. The remaining spacers constitute a second set thereof, each having one of its longitudinal edges exposed at the air discharge face of the filter and the other of its longitudinal edges covered at the air inlet face of the filter. The spacers of the first and second sets alternate, one adjacent the other.

Abstract: A two stage electrostatic precipitator air cleaner having electric field induced airflow. A plurality of spaced parallel fin-like accelerator plates charged to a relatively high negative potential are positioned between the positively charged ionizer wires and the collecting stage of the air cleaner. The electric field induced between the accelerator plates and the ionizer wires induces an airflow for bringing the particles charged by the ionizer wires into proximity with the collecting stage while at the same time charging particles aspirated by the airflow.

Abstract: An automatic current overload protection circuit for electrostatic precipitator power supplies of the type utilizing a ferroresonant transformer. A low voltage tertiary winding in association with the transformer provides an output voltage to a sensing circuit for inhibiting current flow into the primary of the transformer when the tertiary voltage falls below a predetermined threshold. Another output voltage developed in association with the high voltage secondary winding of the transformer is also utilized to independently inhibit current flow into the primary of the transformer when the secondary voltage falls below a predetermined threshold. A time delay may be provided to permit operation of the overload protection circuit only in the event of a sustained overload current condition.

Abstract: The foam cleaning system for an electrostatic precipitator includes a source of a suitable detergent and means for introducing it into a foamer, a source of supply water which is piped through a water pressure reducing valve if necessary and then through a pressure gauge and solenoid valve control and through a suitable filter into the foamer, and a supply of compressed air which passes by suitable conduit through an air pressure regulator and solenoid valve control into the foamer. The detergent, water and air are suitably combined in the foamer and discharged therefrom as a foam into a manifold which will carry the foam to the electrostatic precipitators to be cleaned. The foam is introduced into a space provided at the top of the precipitator above the ionizer and collecting cell plates, between the inlet and outlet filters, and between the side wall of the precipitator. A drain is provided adjacent the precipitator.

Abstract: The means and method for the cleaning and self-cleaning of an electrostatic precipitator is especially suited for adaptation to an electronic air cleaner comprised of an ionizer unit and a collecting cell unit adapted to be included in tandem within a suitable cabinet; means to bring air to be cleaned through these units are also provided, and these may or may not be an integral part of the cleaner. The ionizer unit may include support members for a plurality of ground plates between which are located ionizing wires which normally carry a low current but high voltage, preferably in the neighborhood of 10,000 to 14,000 volts. (Some electronic air cleaners, however, use voltages in the 5,000 to 9,000 volts range. This invention will also work effectively with them.