Showing papers on "Electric discharge published in 1983"

Compact fluorescent lamp unit having segregated air-cooling means

Abstract: Convection air-cooling of a compact electric discharge lamp unit that is adapted for use as a screw-in energy-converv- ing substitute for an incandescent-type lamp bulb is enhanced by partitioning the lamp housing into two separate compartments and providing vents and connecting air passageways that direct ambient air through the respective housing compartments along two different paths thereby cooling the compartments independently of one another. A light source (such as a convolute low-pressure discharge tube) is located within one of the compartments and an electrical circuit for energizing the lamp is located in the other compartment. The "segregated air-flow" mode of cooling prevents heat that is generated by the lamp from being introduced into the compartment that contains the electrical circuit and thus prevents the circuit components from becoming overheated and possibly damaged.

Electric Discharge Pulses in Irradiated Solid Dielectrics in Space

Abstract: Electric charging and discharging phenomena on spacecraft are reviewed. Laboratory tests of spacecraft materials, performed over the last six years by many workers, are summarized. A conceptual framework is proposed to explain the apparently diverse findings and to guide future studies: prebreakdown events (microdischarges) appear to produce small Lichtenberg trees with a plasma which conducts large current under certain conditions. An extensive set of measured pulse data in several polymers is compared to theoretical prediction of radiation induced internal electric fields which rise as high as 2×106 V/cm due to trapped irradiation spacecharge alone. Implications for spacecraft are discussed.

Wire-cut electric discharge machine

Abstract: A wire-cut electric discharge machine having an improved nozzle system for supplying working fluid into a working gap between a workpiece and wire electrode. The improved nozzle system comprises a working fluid nozzle coaxial with the wire electrode and an auxiliary nozzle for producing an intense jet stream in the back portion of the wire electrode, namely, into the slit formed by the spark erosion. The jet stream pressure acts on the semicylindrical surface opposite the front surface at which the discharge pressure is produced to preserve the linearity of the wire electrode.

Wire-cut electric discharge machine

Abstract: A wire cut electric discharge machine provided with a machining fluid supply apparatus capable of supplying machining fluid in an amount large enough to permit a stable wire extension even in a finishing operation. During rough machining, a first flow regulating valve (6) provided in a first pipe (3) and a second flow regulating valve (10) and an on-off valve (11) respectively provided in a second pipe (4) are fully opened, so that machining fluid is injected from upper and lower nozzles (5, 9) respectively connected to these pipes. In the finishing operation, openings of the first and second flow regulating valves are reduced. When wire extension is carried out, the on-off valve in the second pipe is fully closed, and an on-off valve (7) provided in a bypass pipe (8) and fully closed during both the rough machining and the finishing operation is fully opened, whereby an amount of machining fluid large enough to reliably guide a wire electrode is injected from a jet nozzle connected to the bypass pipe and attached to the upper nozzle, regardless of the opening of the first flow regulating valve which varies between the rough machining and the finishing operation.

Cathode-ray tube

Abstract: PURPOSE:To enable spot knocking operation to be effectively performed by connecting a conductive wire, which has an electric-discharge gap, parallel to a path which connects the high-voltage electrode of an electron gun to a high- electric-resistance conductive film provided inside the funnel. CONSTITUTION:An inner conductive film 8 provided inside the funnel 2 of a cathode-ray tube, consists of a film 8a with a low electric resistance and a film 8b with a high electric resistance. A high voltage is applied to a high-voltage electrode 10a of an electron gun 10 through the high-electric-resistance conductive film 8b. Here, a conductive wire 13 having a discharge gap 15 is connected parallel to the path of the conductive film 8b. Therefore, when artificial electric discharge is generated in the high-voltage electrode 10a of the electron gun 10 during spot knocking so as to remove stains and foreign substances, the electric discharge can be carried out through the conductive wire 13 and the discharge gap 15. As a result, the effect of spot knocking can be exhibited without receiving any influence of the high-resistance conductive film 8b.

HgBr(B) formation by electron impact in HgBr2/noble gas discharges

Abstract: The HgBr(B–X) transition forms the basis of an efficient laser at 502 nm. The HgBr(B) state is produced by electric discharge in gas mixtures containing HgBr2. We report measurements of the HgBr(B–X) fluorescence efficiency as a function of electric field in electron beam sustained HgBr2/noble gas discharges. These measurements indicate that the dominant HgBr(B) formation channel is via direct electron impact on HgBr2 by the process HgBr2+e− → HgBr(B)+Br+e−.A Boltzmann analysis is used to derive an empirical cross section for this process.

Electric discharge system including means to normalize the interpole gap to minimize abnormal discharge conditions

Abstract: A voltage sensor senses the gap voltage between an electrode and a conductive workpiece and compares it to a reference voltage using a comparator amplifier. The output from the comparator amplifier is used by an oil hydraulic servomechanism to raise and lower the electrode. An ultrasonic sensor detects impulse waves from discharges and a current sensor detects the working current for determining the working conditions of the gap. After a predetermined number of irregular discharges occurs the gap width may be widened by the servomechanism, the flow of dielectric fluid may be increased to remove sludge and debris, or the time between machining pulses may be increased.

Helical‐flow CO2 laser

Abstract: A CO2 laser based on a helical gas‐flow design has been developed. The major features of this device are as follows: (1) an integral heat exchanger plasmatube with much lower gas flow rates than other convection‐cooled lasers, (2) a multiply segmented plasmatube for high‐voltage standoff, (3) coaxial beam and electric discharge with small diameter‐to‐length ratio resulting in high beam quality and high discharge stability, and, (4) a magnetically stabilized discharge position. Gain profile measurements show that the gain distribution highly favors low‐order modes, as desired. Temperature profile measurements of the gas in the plasmatube verify the efficiency of the integral heat exchanger concept. Specific laser configurations based on this design concept, intended for industrial material‐processing applications, and with output powers of 400–500 W/m, are described.

Catalyzed sealed-off CO2 laser

Abstract: A sealed-off CO2 laser employs a catalyst to promote the recombination of CO and oxygen. The catalyst is loosely contained within a catalyst holder having a plurality of apertures and the catalyst is brought into contact with the gas by means of the pressure pulse caused by the electric discharge.

Microdischarge characteristics in air gap between spherical particle and plane

Abstract: Microdischarge behaviours in a gap between the plane electrode and a charged conducting spherical particle moving in the presence of external electric field have been investigated. The microgap studied has distinctive features: (a) the field strength in the microgap changes very rapidly with the motion of the sphere even if the applied external electric field is static, (b) the boundary of the microgap changes with time and (c) the potential difference across the microgap is influenced from the occurrence of discharge due to the neutralisation of charge on the sphere by the charge carrier in the discharge itself. The random appearance of an initiating electron required for the development of an avalanche and the rapid changes of electric field, gap boundary and potential difference result in the statistical behaviours of microdischarge. The statistical characteristics at the microdischarge threshold and on the microdischarge length have been measured, and the microdischarge mechanism has been discussed to explain the characteristics.

Electrode cutting apparatus for wire cut electric discharge machine

Abstract: A wire electrode cutting apparatus for use in a wire-cut electric discharge machine mounted between a supply section for the wire electrode and a pulling section therefor, and comprising a device for applying a constant tensile force to the wire electrode and for sensing that the constant tensile force has been applied thereto, and a power supply for applying an electric current to the wire electrode to heat the same when a predetermined tensile force has been applied thereto.

Method for producing a fluorine-containing amorphous semiconductor

Abstract: Production of fluorine-containing amorphous semiconductors having high thermal stability, photoconductivity and photosensitivity by decomposing a mixed gas of silicon difluoride gas or silicon monofluoride gas with hydrogen gas or hydrogen atom gas, or SiFH 3 gas or SiF 2 H 2 gas with electric discharge and depositing the decomposed gas on a substrate.

Laser utilizing a gaseous lasing medium and method for operating the same

Abstract: The invention relates to an improvement in gas lasers and a method of operating the same. In one aspect, the invention is an improved method for operating a high-power gas laser. The improvement comprises introducing the gas lasing medium tangentially to the laser tube at a pressure establishing a forced vortex in the tube. The vortex defines an axially extending core region characterized by a low pressure and temperature relative to the gas inlet and the exterior of the vortex. An electrical discharge is established in the core region to initiate lasing of the gas. The gas discharge from the tube is passed through a diffuser. As in conventional gas lasers, firing results in a very abrupt increase in gas temperature and in severe disruption of the gas. However, the gas vortex almost immediately restores the gas to its pre-firing condition. That is, almost all of the waste heat is transferred radially to the laser wall, and the original gas-flow pattern is restored. As a result, the power output of the laser is increased significantly, and the laser firing repetition rate is markedly increased.

Gas laser excited by a transverse electrical discharge triggered by photoionization

Abstract: An X-ray generator 7 directly connected to the electrode 8 internally of a hollow cathode 3 emits electrons under a field effect to generate X-rays, the generator 7 supplying 50 to 100 Kv with a rise time of less than 10 nanoseconds. X-rays rapidly created, in turn, rapidly create electrons in the active medium 1 between anode 2 and cathode 3 to trigger a discharge therebetween, across which anode and cathode the voltage of a laser capacitor is pre-applied at a level below the breakdown voltage of the active medium.

Control of wire-cut electric discharge machining unit

Abstract: PURPOSE:To redcue the working error on corner working within the permissible value by correcting the electric discharge power on corner working, the tension of a wire electrode, and the feeding speed, on the basis of the deflection amount of the wire electrode when straight working is preformed. CONSTITUTION:When a corner part is worked through the wire-cut electric discharge machining, working errors 3a and 3b are generated according to the deflection amount of a wire electrode 1. The work instruction data read from a tape reader 26 is stored in a memory 28, and treated in a calculation unit 25, and the brake roller controlling circuit 9 of the wire electrode, work-feeding motor controlling circuit 22, and a power source condenser switching circuit 7 are controlled through an interface 29. The working power, the tension of the wire electrode, and the feeding speed are calculated and corrected according to each deflection amount D1, D2 in case of straight working so that the corner error delta can be reduced within the permissible value.

Electric discharge machine with control of the machining pulse's current value in accordance with the delay time

Abstract: In an electric discharge machine having a main switching circuit 24 for supplying a current high in current peak value between which are an electrode 10 and a workpiece 12, and an auxiliary switching circuit 26 for supplying a current low in current peak value between the electrodes, to intermittently cause electric discharge between the electrodes which are the electrode 10 and the workpiece; a voltage is applied across the electrodes by the auxiliary switching circuit 26, and when no electric discharge occurs between the electrodes before a decision set time of 1 to 4 μsec, the application of the voltage across the electrodes by the auxiliary switching circuit 26 is continued until discharge occurs therebetween and when the discharge occurs the main switching circuit 24 is caused to supply a normal current between the electrodes according to a given surface roughness, and when discharge or short-circuiting occurs between the electrodes before the decision set time the main switching circuit 24 or the auxiliary switching circuit 26 is caused to supply a current smaller than the normal current between the electrode. As a result the machining speed for the surface roughness of the workpiece is increased, and the machining stability is improved.

Photodetachment as a Control Mechanism for Diffuse Discharge Switches

Abstract: Photodetachment is considered as a control mechanism for diffuse discharge switches. Experiments have been performed on photodetachment of ions in the flowing afterglow of a dc glow discharge in oxygen. Experiments with different laser wavelengths and the dependence of the optogalvanic signal on the laser energy flux indicate that O- is the dominant negative ion. For an energy flux of 35 mJ/cm2, 50percent of the O- ions can be photodetached.

Influence of premolding pressure in electric-discharge sintering on the physicomechanical properties of a copper-tin-abrasive composite

Abstract: It was established that the premolding pressure in electric-discharge sintering has a significant influence on formation of the properties of the material from a copper-tin-abrasive composite.

Mechanism of pulse emission from high-pressure electric-discharge He?Ar, He?Kr, and He?Xe infrared lasers

Abstract: A study was made of the time dependences of the amplitudes of stimulated and spontaneous emission from pulsed electric discharges in He?Ar, He?Kr, and He?Xe mixtures, and the processes involved in populating the active levels were analyzed. Direct and stepwise excitation by electrons was taken into account, as was population resulting from relaxation processes (collisions of the second kind with electrons, radiative cascades, recombination processes, collisions with atoms of the active and buffer gases, excitation transfer from the helium molecules). A qualitative picture was obtained of the characteristic processes for populating the atomic levels of Ar, Kr, and Xe as a function of the composition and pressure of the mixtures. It was established that the decisive mechanism at high pressures involves direct excitation by electron impact from the ground states.

Electric discharge machine including means for detecting abnormal discharge conditions

Abstract: In an electric discharge machine including an electrode and a workpiece installed opposite each other with an insulating working liquid filling the gap therebetween and which is used to machine the workpiece by causing an electric discharge across the gap, two components of the frequency spectrum of the voltage waveform of the electric discharge across the electrode and the workpiece are analyzed to distinguish between normal and abnormal discharge conditions. The device includes elements for determining the conditions in the gap and which generate a signal according to the conditions of the interpole gap, based on the results of this analysis. When an abnormal condition exists, the size of the interpole gap may be changed, and the quiescent time between application of pulse voltages may be altered. Also, depending on the degree of abnormality, different quantities of dielectric fluid may be pumped through the interpole gap to remove accumulated impurities.

Catalyzed CO2 laser

Abstract: A CO2 laser, especially a sealed laser, employs a catalyst to promote the recombination of CO and oxygen. The catalyst is contained within a porous electrode forming one of the laser discharge electrodes and is brought into contact with the gas by means of the pressure pulse caused by the electric discharge, by diffusion or by circulating the gas. A preferred structure comprises catalyst pellets contained within a wire mesh electrode.

Decomposition Products of Silicone Liquid Due to Electric Discharge

Abstract: Silicone liquid can be used at relatively high temperatures, for instance as an impregnant in transformers for use in trains, because it has high thermal stability and low flammability. This paper describes decompositions of silicone liquid due to electrical discharges, such as arc discharge and partial discharge. It was found that hydrogen, carbon monoxide and cyclic dimethyl siloxane (D4) are produced due to electrical discharge as in the case of thermaln degradation. However, only one kind of dimethyl siloxane (D4) was found, whereas D3, D4, D5, and D6 were found in thermal degradation [2]. Moreover, the ratio of the gaseous products to cyclic dimethyl siloxane compounds for partial discharge is much smaller than the same ratio for arc discharge. In both cases the ratio is much larger than the ratio found for thermal degradation [2].

X-ray tube with encircling ceramic case

Abstract: PURPOSE:To obtain an X-ray tube, the encircling ceramic case of which can be handled easily and the creeping discharge of the inner surface of which is suppressed, by causing small electric discharge by coating the inner wall of the encircling ceramic case with a cover coat, and scattering fine metal particles over the surface of the cover coat at minute intervals. CONSTITUTION:As a cover coat 10, a glass member having high insulating resistance is used in order to maintain its insulating performance and to prevent any dirt from entering among the ceramic particles of an encircling ceramic case 1. By scattering a fine metal particle group 11 over the cover coat 10, any high electric-potential difference, which might be caused due to a large amount of electric charges which might be accumulated in local parts of the inner wall of the case 1, is prevented from developing between the above local parts and from growing into intensive electric discharge. The above metal particle group 11 is formed by scattering metal particles, for example, copper particles with a grain diameter of around 10-100mum at intervals equal to the diameter of the metal particles, by a slow sputtering or other proper means.

19—electrical-discharge treatment of wool at atmospheric pressure

Abstract: Electrical-discharge treatment of wool fabric at atmospheric pressure increases its wettability and dye absorption. An investigation is described in which the best results were obtained with a glow discharge produced by using a small air gap between the electrodes, low fabric regain, and low relative humidity. With increase in the size of the air gap, regain, and r.h., the discharge was characterized by streamers or sparks or both, and the improvements in wettability and dye absorption were not as good.

Corona Pulse Charge Transfer at Elevated Frequencies

Abstract: A technique is described for measuring corona pulse charge transfer per cycle as a function of frequency. It is found that, with a parallel-plane gap geometry employed, the corona charge transfer per cycle exhibits a non-linear decrease with frequency. The result implies that in accelerated life tests on insulating materials and systems, the degradation rate in the presence of corona discharges may not necessarily be a lineraly increasing function of the test frequency.

Analysis of radial distribution of plasma parameters in a coaxial-line microwave discharge tube

Abstract: The discharge mechanism in a coaxial‐line microwave discharge tube that makes uniform plasma along the circumference of the tube has been analyzed. The analysis includes the skin effect of microwave penetration into the plasma and the equilibrium between generation and losses of the charged particles. It is shown that the radial distributions of electron density and electron temperature can calculated from measured values of the radial distribution of light intensity. The electron density is about 1012 cm−3 near the center axis of the plasma column and is close to trapezoidal in shape. The electron temperature is about 4×104 K near the tube wall and decreases monotonically toward the center of the plasma column.