Abstract: An electro-inertial precipitator unit for removing particulate contaminants from a gaseous stream passing through a collector tube having a discharge electrode coaxially disposed therein to establish an electrostatic field between the electrode and a downwardly-flowing water film on the inner surface of the tube. The gaseous stream is introduced tangentially into an upper inlet section of the tube to impart a swirling motion thereto, the water being supplied to an annular inlet slot just below the gas inlet section. Because of the centrifugal force generated by the cyclonic motion, the particles in the gaseous stream are urged to migrate toward the water film, this migration being further promoted by the electrostatic force acting on the particles which are charged with ions in the field. Air is blown over the surface of the upper lip of the water inlet slot to prevent wetting of this surface and the deposition of dust therein.

Abstract: An electro-inertial precipitator unit for removing particulate contaminants from a gaseous stream passing through a collector tube having a discharge electrode coaxially disposed therein to establish an electrostatic field between the electrode and a downwardly-flowing liquid film on the inner surface of the tube. The gaseous stream is introduced tangentially into an upper inlet section of the tube to impart a swirling motion thereto, the liquid being supplied to an annular inlet slot just below the gas inlet section. Because of the centrifugal force generated by the cyclonic motion, the particles in the gaseous stream are urged to migrate toward the liquid film, this migration being further promoted by the electrostatic force acting on the particles which are charged with ions in the field. To avoid wetting of the inlet section, thereby causing dust to deposit thereon, this inlet section is provided with a hydrophobic surface in the region above the inlet slot.

Abstract: An electro-inertial precipitator unit for removing particulate contaminants from a gaseous stream passing through a collector tube having a discharge electrode coaxially disposed therein to establish an electrostatic field between the electrode and a downwardly-flowing liquid film on the inner surface of the tube. The gaseous stream is introduced tangentially into an upper inlet section of the tube to impart a swirling motion thereto, the liquid being supplied to an annular inlet slot just below the gas inlet section. Because of the centrifugal force generated by the swirling motion, the particles in the gaseous stream are urged to migrate toward the liquid film, this migration being further promoted by the electrostatic force acting on the particles which are charged with ions in the field. To avoid the formation of dust streaks on the inner surface of the tube, which tend to occur with relatively low liquid flow rates, the gaseous stream flowing therethrough is pulsed.

Abstract: An intelligent test head which can be plugged into an existing computer-controlled automatic test system that is adapted to carry out certain tests on integrated circuits and discrete devices, the test head making it possible for the system to execute special tests which the system is otherwise incapable of performing. The existing system includes a main frame computer associated with a programmer. A device under test is linked by a pin electronics board to the computer through a relay interface board which acts to selectively couple a forcing supply, a function generator or other testing sources to the device, which sources are appropriate to the normal test capabilities of the system. When plugged into the system, the intelligent test head is interposed between the pin electronics board and the device then under test.

Abstract: A transfer assembly interposable between a storage tube containing semiconductor devices and a processing station therefor, the assembly effecting a controlled electrostatic discharge of each device taken from the tube to prevent a destructive discharge thereof. The transfer assembly includes an insulating track adapted to receive semiconductor devices from the storage tube, each lead of the device received on the track being engaged by a pair of Kelvin contacts, one of which is connected by a normally-open high impedance relay to an input of a test system for the device, the other being connected to ground through the high-impedance drain and source channel of a field effect transistor. Applied to the gate of the transistor is a ramp voltage causing the channel impedance to diminish at a slew rate producing a gradual and safe bleed of the electrostatic charge carried on the engaged lead. At the conclusion of the discharge cycle, the relay is actuated to connect the lead to the test system.

Abstract: A bridge-balancing system for measuring minute current flows in devices having an extremely high impedance, the bridge having two sets of opposing arms to define input and output diagonals. A direct voltage is applied to the input diagonals and an amplifier having a high input impedance is connected to the output diagonals to yield an analog signal whose sense and magnitude depend on the degree to which the impedance of the device under test which forms one arm in one set differs from that of an adjustable high-impedance element forming the opposing arm of that set, a pair of fixed matching resistors defining the arms of the other set. The adjustable element is constituted by a field effect transistor operating in its variable resistance region wherein the extremely high impedance presented thereby depends on the applied gate potential.

Abstract: An inertial-electrostatic wet precipitator for removing particulate contaminants from a gaseous stream passing through a collector tube having a discharge electrode assembly coaxially disposed therein to establish an electrostatic field between the assembly and a liquid film on the inner surface of the tube which acts to ionize the particles in the gas. Liquid for flushing the particles is fed through a pipe spiralled about the precipitator tube, the pipe terminating in a nozzle ejecting the liquid tangentially into the inlet section of the tube to impart cyclonic motion thereto. As a result, liquid is caused to flow against the inner surface of the tube in a helical path to produce the liquid film which flows toward the outlet section of the tube and is discharged into a sump.

Abstract: A thermal print head including a conductive base plate, a substrate slab mounted on the base and having various deposits on the upper and lower surfaces thereof, such deposits including conductive traces, conductive leads, a thermally insulating material, resistors, and conductive deposits for delivering electrical potential across the resistors, one or more integrated circuits mounted on the slab for controlling said print head based on electrical signals from external data processing equipment and connectors for delivering signals and potentials to the print head.

Abstract: A probe operable in conjunction with an electrometer having a high input impedance to provide an instrument for measuring air ion flux density. The probe structure is such that its presence in the atmosphere in which a measurement is being carried out will not give rise to perturbations in the localized electric field and therefore has no perceptible effect on the accuracy of measurement. The probe is constituted by a metal target to which the ions give up their charge, the target being supported at the end of a barrel of dielectric material by a conductor attached thereto and extending axially through the barrel to a contact at the rear of the barrel which is connected to the line of a shielded coaxial cable which couples the target to the input terminal of a grounded electrometer, the shield of the cable also being grounded. The surface of the barrel is coated with a layer of semi-conductive material that makes contact at the lower end of the barrel with the grounded cable shield.

Abstract: A voltage source adapted to excite a gas-ionization electrode so as to generate copious amounts of ionized gas without, however, producing measurable amounts of undesirable reactive or toxic chemical by-products. Yielded by the source is a unipolar voltage wave having a steady state DC component which, though below the ionization potential, serves to condition the gas to promote ionization. Imposed on the steady-state component is a gas-ionization component in the form of low-frequency surges, each composed of a short series of high-frequency pulses having a brief duration and an extremely high peak amplitude. The duration of the surge pulses is insufficient to break down the gas chemically, but the amplitude thereof is such as to effect intense gas ionization. The steady-state component prevents the electric field from collapsing completely in the intervals between pulses, thereby keeping the gas at a level approaching its ionization potential.

Abstract: An electrostatic precipitator for extracting particles and other contaminants from a gaseous stream to be purified, the contaminants being ionized by means of a discharge electrode structure which includes a column of dielectric material whose central axis is coincident with the axis of a collector tube within which the column is disposed. The column has a cross-sectional geometry that defines a circular series of longitudinally-extending niches. Supported between the ends of the column is a circular array of fine gauge wires each of which is suspended with a respective niche. A high voltage is impressed between the wires in the array and the inner surface of the collector tube to create an electrostatic field in the annular region between the discharge electrode structure and the tube to ionize contaminants in the gaseous stream passing therethrough.