Illinois Tool Works Inc.

Itw Limited

Timothy A Good

Richard D Rodrigo

Positive and negative ion output are balanced in an electrical ionizer having positive and negative ion emitters, and positive and negative high voltage power supplies associated with the respective positive and negative ion emitters. At least one of the positive and negative high voltage power supplies switches between a high state and a low state. An ion balance sensor is located close to the ion emitters and outputs a voltage value. An ion balance sensor set point voltage value is stored. The voltage value is set to provide a balanced ion condition in the work space near the electrical ionizer. During operation of the electrical ionizer, the output voltage value of the ion balance sensor is compared with the set point voltage value. One of the switchable high voltage power supplies is switched to a high state when it is detected as a result of the comparison that the output voltage value of the ion balance sensor exceeds the set point voltage value in a first direction by a first predetermined amount, and the one of the switchable high voltage power supplies is switched to a low state when it is detected as a result of the comparison that the output voltage value of the ion balance sensor exceeds the set point voltage value in a second direction by a second predetermined amount, the second direction being opposite of the first direction.

Instantaneous balance control scheme for ionizer

A self-cleaning, anti-fouling, ionizing air gun for static neutralization and particle blow-off comprises a generally tubular barrel having an open forward or nozzle end and a rearward open end for drawing air therethrough from the atmosphere. A pointed ion emitting electrode is positioned intermediate the ends of the barrel and directs ions toward the forward nozzle end while a plurality of circumferentially spaced air jets direct streams of compressed air in a conical pattern toward the apex thereof in front of the ion emitting electrode so as to induce air drawn in from the open rear end over the electrode to effect cleansing thereof thereby expelling a high velocity ionized air stream through the forward nozzle end.

Self-cleaning ionizing air gun

Granule cleaner and method comprises a hollow elutriation column into which dust- and debris-adulterated pellets are blasted on a high velocity air stream through an upwardly inclined injection tube to form a floating suspension in said column. Suction withdraws the lighter suspended material from the top while the heavier particles fall to the bottom. A.C. electrostatic dischargers diametrically disposed opposite conductive portions of the injection tube which may be ground-isolated (and also opposite ground-isolated conductive portions of the column below the injection level of the granules therein) to neutralize both the entering contaminated granules and the falling cleansed pellets, the conductive ground-isolated portions defining reference electrodes for balancing ion emission.

Elutriation apparatus and method for cleaning granules

A self-balancing ionizing circuit for electrical static eliminators having high voltage (pointed) discharge electrodes employs an insulative duct spaced peripherally thereabout. The duct has at least an open exit end with a non-conductive protective grille at the duct terminus in longitudinally spaced disposition from said electrodes. One side of an ungrounded secondary coil of an A.C. high voltage transformer is directly or resistively connected electrically to the discharge electrodes while the other side of the transformer secondary is electrically coupled to an ungrounded conductive band supported within the insulative duct adjacently spaced from the discharge electrodes to define a floating reference electrode with respect thereto. The electric field for ionization is produced between the discharge electrodes and the reference electrode. Grounding is effected only by way of an external conductive chassis for the system which is shielded from the internal ionization process by the dielectric of the insulative duct. Isolating the reference electrode from ground permits substantial voltages to be developed thereon without creating the ionization imbalance normally produced by adjacent grounded components, such as grounded casings or the like. Balancing of positive and negative ion production is independent of capacitors or other electrical components, and no mechanical adjustment is required to compensate for changes in environmental factors or contamination conditions. With no capacitors which can become leaky, the system provides high reliability with fewer parts, thereby minimizing costs.

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Royersford, PA, United States of America

Timothy A Good