Westinghouse Electric Corporation

Other

Richard L Hundstad

Owen Farish

John L Pack

Paul O Wayland

Lelland A Weaver

Joseph G Gorman

Roy E Voshall

Ira E Kanter

Steve A Wutzke

Richard V Babcock

A system is described for use in the stack or flue ducts of a fossil fueled combustion system to eliminate or substantially reduce SO.sub.x and NO.sub.x emissions. The system includes an electrically operated stable glow discharge maintained between separate resistively ballasted pins and opposing plane electrodes. The electrochemical reactor of this invention electronically activates, reacts and chemically modifies the selected pollutants to render a thermodynamically stable solid product.

Stack gas emissions control system

Novel techniques for scattering infrared radiation are employed to form a diffuse retro-reflector suitable as a target for night viewing by an infrared responsive detector.

Infrared radiation responsive target

A glow discharge device positioned upstream in a flow laser gas system supplies a continuous flow of electrons to a laser discharge region defined between planar laser electrodes to develop sufficient background electron density to permit CW or quasi CW laser operation.

Technique for CW or quasi CW operation of planar electrode laser

The discrete ballast resistors associated with the multiple pin array of laser cathode structures are replaced by a bulk resistive material in the form of an integral bar or slab which is maintained in contact with the plurality of pin electrodes comprising the laser cathode assembly to provide a stable ballast means. The bulk resistive member employed to provide the ballast for the pin electrodes can exhibit non-linear resistive characteristics to provide greater laser discharge stability with less power dissipation.

Ballast technique for laser cathode pins

Described herein is a technique for removing gas constituents residing in the aerodynamic boundary-layer developed along the surfaces of electrodes in a flowing gas laser system, which gas constituents contribute to adverse arc conditions.

Technique for minimizing arc conditions in a flowing gas laser system

A vacuum circuit interrupter contact being generally cup-shaped with a radially inward extending lip with slots formed through the lip and side wall for directing current flow and including a flat annular contact cap attached directly to the lip portion. The annular contact cap extends from the side walls radially inward to a position inside of the lip-shaped portion. At the inner diameter of the annular contact cap an arcing ring is formed which extends downward along the inner diameter of the lip portion. The annular contact cap can be formed from a material having good arc interrupting properties, such as chromium copper, while the rest of the contact can be formed from a material which is easy to fabricate and has good electrical conductivity properties, such as copper. In another embodiment of the invention, the lip portion and the annular contact cap are formed as one member but any slots formed in the lip-shaped portion do not extend to the contact making surface. Thus the contact making surface is still in a continuous annular contact area. The contact structure is shaped so that when an arc is formed during circuit interruption the arc is moved radially inward and around the arcing rings of the pair of contacts. The disclosed contacts provide high current interrupting ability with little arc-seasoning.

Cup-shaped contacts for vacuum interrupters having a continuous annular

The complexity of the conventional X-Y array of pin type cathode electrode elements employed in high-power gas laser systems, is reduced by substituting a continuous elongated cathode electrode element for one or more rows of discrete pin type cathode elements.

Cathode electrode configuration for gas laser system

A transverse gas flow system in combination with physically displaced electrical dissociation and electrical excitation means permits increased pulse repetition rates resulting in increased average power output from a metal halide laser apparatus.

High repetition rate metal halide laser

A trigger circuit which operates independently of the main discharge circuit can be used to initiate glow discharge useful for gas laser excitation. By utilizing independent trigger means, such as auxiliary dielectric electrodes, the main discharge can be controlled by modulating only a small part of the total energy input to the laser cavity. The main discharge gap of the laser is prestressed to a voltage below the spark breakdown voltage threshold of the electrode assembly under static conditions but above the glow discharge voltage of the electrode assembly. When the trigger means is pulsed to supply free electrons to the discharge gap the glow discharge is initiated between the electrodes independent of the need for modulating the main power to the gap.

Independent initiation technique of glow discharge production in

A gas laser system with moderate speed gas glow through the optical cavity to facilitate D.C. excitation of the gas to lasing levels. An electrode assembly is positioned so as to provide a glow discharge transverse to the optical axis within the optical cavity when a high D.C. voltage is applied thereto. By maintaining the high rate of flow of gas through the cavity, the glow discharge is stabilized while the gas medium is maintained at high pressure. Proper choice of electrode geometry and flow rate of the gas through the optical cavity allows the laser system to operate at pressures from a few Torr to atmospheric pressure and above thereby producing a high power CW output.

D.C. Excitation of high pressure gas lasers

A uniform field electrode arrangement for exciting a laser gas in a high pressure pulsed gas laser apparatus so constructed to facilitate discharge initiation and smooth laminar gas flow. The geometry of the electrode assembly provides for laminar gas flow through the discharge volume providing an optically homogeneous lasing medium. Discharge initiation for pulsed operation is achieved using, for example, ultraviolet irradiation of the electrode assembly, corona discharge devices and radioisotope irradiation of the electrode assembly. Independent of the type of initiatory discharge device used, the geometry of the assembly allows for efficient supply of initiating electrons to the discharge gap without interference with smooth gas flow through the optical cavity. Mesh electrodes can be used to facilitate gas flow in a direction parallel with the direction of electrical discharge.

Laser cavities with gas flow through the electrodes

A gas laser tube apparatus for producing a high-current glow, arc or spark which generates initiatory electrons and charged particles for establishing excitation of gas molecules in a separate region of the tube. Separate regions of ionization and excitation are established so that uniformity of excitation, optimization of the ratio of electric field intensity to electron density (E/N) and uniform intensity of excitation can be obtained in a high pressure gas laser system independent of ionization or initiation of discharge which also may need to be optimized. The separate fields are achieved by proper configuring of the electrodes with appropriate voltages applied thereto.

Generation of corona for laser excitation

A method is described for forming contacts which find use in vacuum interrupters. The method comprises making melt of a first metal having a high electrical conductivity and adding to the melt a second metal having a melting point in excess of the first metal and solubility in the first metal of less than 1 percent at the temperature to which the first metal is heated, intermixing the components to a uniform consistency casting the components to the desired configuration and thereafter cooling to room temperature.

Growing community of inventors

Wilkinsburg, PA, United States of America

Richard L Hundstad