Abstract: An improved system and a novel vessel and method for treating contaminated liquids, e.g., aqueous effluent streams, contaminated with a variety of contaminants. The vessel comprises upper and lower mixing chambers connected by an intermediate tubular section and a fluid exit tube running coaxially down the center of the intermediate tubular portion. The contaminated fluid stream to be treated flows in a spiral pattern generally upwardly entering the exit tube at its upper end and flowing downwardly to a lower exit. A magnetic field may be induced in the flow stream. Streams of the fluid to be treated and of an ionized coagulant are combined prior to entry into the vessel and are subjected to very turbulent flow and to the magnetic field, to encourage both very thorough mixing and magnetic coalescing of the coagulant with the fluid to be treated. Magnetite particles may additionally be added to the flow stream to further encourage coagulation in the presence of a magnetic field.

Abstract: Air ionizing apparatus that produces both positive and negative ions has a housing with air inlet and outlet passages, a plurality of spaced apart air ionizing electrodes and a high voltage supply which applies positive and negative voltages to separate electrodes. A fan creates an airflow that carries the ions out of the housing, the fan preferably being between the electrodes and the outlet passages to promote intermixing of positive and negative ions. The high voltage region of the high voltage supply is isolated from any direct current path to ground. The electrodes then inherently acquire a D.C. voltage bias, when necessary, that maintains an equal output of positive and negative ions without requiring use of an air ion sensor and feedback circuit for the purpose.

Abstract: A test chamber is disclosed that permits standardized measurement of particles in the chamber environment. A device or structure that is suspected of the emitting particles and which is desired to be tested is located within the chamber. The chamber environment is then controlled by the introduction of filtered air thereby permitting both static measurements of particle emissions from the device or structure and flow through measurements of particle emissions from the device or structure.

Abstract: Ion content of the atmosphere at a particular location is controlled by generating ions during repetitive period that are initiated by timing signals which reoccur at a predetermined rate. An ion sensor produces feedback signals indicative of the ion content of the air and a feedback circuit varies the duration of the recurring periods of ion generation, if necessary, to maintain the ion content within a predetermined range. Positive and negative ions may be generated during alternate ones of the repetitive periods in which case the feedback circuit inversely varies the periods of positive and negative ion generation to maintain the relative proportions of the two types of ion within a predetermined range. The method and apparatus may be used to suppress accumulation of electrostatic charge by objects, such as in a clean room where electronic components are manufactured, or for other purposes requiring control of the ion content of air.

Abstract: Ion content of the air in a clean room or the like is controlled by generating positive and negative ions during alternating time periods using positive and negative high voltage generators connected to ionizing electrodes. Ion generation periods are followed by off intervals during which the ions disperse away from the electrodes before ions of opposite polarity are generated. In one aspect of the invention, each period of actuation of a high voltage generator of one polarity is followed by a momentary actuation of the high voltage generator of opposite polarity. This produces ions that are attracted to the electrode of the one polarity and then neutralize residual charge on the capacitors of the generator of the one polarity thereby assuring an abrupt termination of ion generation which can otherwise extend into the subsequent off period.

Abstract: Potentially damaging electrostatic charges on semiconductor wafers or other objects are suppressed during the manufacturing process by generating ions in a flow of nitrogen or other non-reactive gas and by delivering the ionized flow to the product region through an enclosed flow path. The ions are produced by directing X-rays or other ionizing radiation into a shielded chamber portion of the flow path where flow is relatively slow and a large volume of gas is exposed to the X-rays. The ionized flow is then transmitted to the product region through a relatively narrow tubulation in which flow velocity is higher. Inter-relating of the flow rate and the length and diameter of the delivery tube minimizes ion loss from contact with the tube wall and from charge exchange with each other. The process and apparatus do not generate ozone or metallic particles, which can damage the products, as may occur with prior systems which use high voltage electrodes to ionize the air.

Abstract: Apparatus for ionizing air molecules to suppress electrostatic charges in a room or for other purposes includes internal feedback which maintains a desired rate of ion production in the presence of electrode deterioration or other effects which could otherwise alter ion output. Production of air ions of a given polarity results in a ground return flow of electrical charges of opposite polarity from the high voltage generator at a rate corresponding to the rate of air ion output. The ground return current is monitored to produce an electrical feedback signal. A control circuit causes the high voltage generator to apply higher voltage to the electrode when the feedback signal decreases and to apply lower voltage to the electrode when the feedback signal increases. Such self-regulation of each individual electrode in systems having an array of electrodes that are otherwise jointly controlled acts to maintain a desired ratio of positive and negative ions in a room as well as a desired total ion concentration.

Abstract: Positive and negative ion contents of the air within a region are controlled to suppress build-up of electrostatic charges on objects or for other purposes with one or more air ionizing units each having a positive high voltage generator coupled to a first ionizing electrode and a negative high voltage generator coupled to a second spaced apart ionizing electrode. The positive and negative high voltage generators are operated alternately with off times being provided between each period of ion generation of either polarity and the preceding period of generation of ions of the opposite polarity. The off times enable ions of each polarity to disperse outwardly for a controlled distance before substantial intermixing and mutual neutralization takes place.