Abstract: An apparatus for condensing water vapor and vaporized solvent from process exhaust gas, such as from an industrial solvent drying oven process is described. The apparatus includes two parallel condenser assemblies which are alternately shifted between condensing and defrost modes. One of the assemblies is shifted into the condensing mode while the other is in the defrost mode and the other is shifted into the condensing mode while the one is in the defrost mode. When in the condensing mode, water vapor is condensed from the process exhaust gas in a water condenser such as a counterflow heat exchanger and solvent vapor is condensed therefrom by a solvent condenser such as a refrigeration coil positioned within a cold zone of the assembly. When in the defrost mode, a recirculating defrost loop is provided through which gas is circulated and heated for defrost purposes. Following defrosting, the defrosted condenser assembly is pre-cooled prior to shifting from the defrost mode back to the condensing mode.

Abstract: An electrostatic precipitator air cleaner having a novel ionizer cell made up of a plurality of positively charged wire-like ionizer electrodes, a plate-like negatively charged passive electrode positioned between and parallel to each adjacent pair of ionizer electrodes, and a box-like enclosure surrounding the ionizer cell such that the side walls of the enclosure adjacent the outermost ones of the ionizer electrodes form grounded electrically conducting surfaces, a relatively high electrostatic field being produced in the region between the ionizer electrodes and the passive electrodes and between the ionizer electrode and the grounded surfaces. In a preferred embodiment, the ionizer electrodes and passive electrodes are impressed with relatively high voltages of equal but opposite polarity such that the spacing between an ionizer electrode and an adjacent passive electrode is twice the spacing between an ionizer electrode and the adjacent grounded surface.

Abstract: An automatic electronic reset current cut-off protection circuit for electrostatic precipitator air cleaner power supplies of the type utilizing a ferroresonant transformer having a primary winding, a secondary winding for producing relatively high voltage and a tertiary winding for producing a relatively low voltage. The circuit operates to inhibit power supply operation in the event of an overload in the ionizer or collector cell by sensing a voltage derived from the high voltage and comparing the sense voltage with a fixed reference. When the sense voltage falls below a predetermined value, current through the transformer primary is inhibited for a predetermined time. Current flow is automatically reinstated and the circuit will cyclically cause the power supply to shut down until the fault has cleared. The reference voltage is derived from the tertiary winding voltage resulting in increased sensitivity of the circuit to short duration overload conditions.

Abstract: Apparatus for providing source capture of fumes produced at a work station including a molded aerodynamically designed fume capture hood positionable above the work station, a mounting mechanism for providing vertical movement of the hood such that the orientation of the hood opening remains constant, a fume collection system for removing material contained in air captured by the hood, and a flexible conduit connecting the collection system to the hood. The contours associated with the forward parts of the upper and side wall portions of the hood minimize entrance loss and turbulence to provide a coefficient of entry of at least about 0.93, while the contour associated with the forward part of the upper wall portion permits a higher velocity near the top of the hood for insuring suction of fumes, vapors or smoke near an operator's breathing zone.

Abstract: A high voltage monitor and display for electrostatic precipitators producing a digital output code representing the magnitude of the high voltage associated with the ionizer and collecting cells which is applied to a series of display elements arranged in a spaced linear relationship such that the number of adjacent display elements illuminated corresponds to the magnitude of the high voltage to provide a visible indication of ionizer cell and collector cell performance. A predetermined minimum cell voltage is established digitally, and the high voltage power supply inhibited when the high voltage falls below the predetermined value. Alarm means are also provided for indicating when the collector cell or ionizer cell voltage is below the predetermined operating minimum.

Abstract: An electrostatic precipitator air cleaner including a number of precipitator cells having spaced parallel plates for collecting dirt particles, and a vertically disposed traversing pipe-like spray header containing a number of spray nozzles for directing a spray of wash or rinse fluid onto the collecting plates in order to remove collected particles. The header is traversed horizontally across the precipitator cells by means of a trolley supported by a rail-like guide member and reciprocated between a home position and an extended position by means of a rotating elongated helical drive screw cooperating with a gear-like follower attached to the trolley, such that the rotation of the screw produces linear motion of the header. The header is connected to a source of wash or rinse fluid by means of swivel connections and a flexible conduit.

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: A method and apparatus for treating electrically charged airborne particles to reduce deposition of the particles on walls and other exposed surfaces in an enclosed area. Air containing positively charged particles exhausted from a first group of electrostatic precipitators is admixed with air containing negatively charged particles exhausted from a second group of electrostatic precipitators, the mixed air containing oppositely charged particles having less tendency to become deposited on walls and other surfaces in the enclosed area.

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: A circuit for controlling the duty cycle of a two-stage electrostatic precipitator power supply. The circuit includes a switching device connected in series with the primary winding of the power supply transformer and a circuit operable for controlling the switching device. A capacitive network, adapted to monitor the current in the primary winding of the power supply transformer, is provided for operating the control circuit. Under normal operating conditions, i.e., when the current in the primary winding of the power supply transformer is within normal limits, the capacitive network operates the control circuit to allow current flow through the power supply transformer primary winding in a normal manner.

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.

Abstract: A method and apparatus for removal of acidic gases from a gas stream by contacting the gas stream with an amine vapor in a reaction zone. The partial pressure of amine vapor in the reaction zone is at least 5 percent of the total pressure therein, resulting in removal of at least 99 percent of the acidic gases. When operating at ambient temperature and substantially atmospheric pressure, preferred amines are methylamine and dimethylamine.