Showing papers on "Electric discharge published in 1982"

Method and apparatus for electrohydraulic fracturing of rock and the like

Abstract: Electrohydraulic fracturing of rock and other dense materials is accomplished by coupling a hydraulic medium to the material to be fractured and inducing an explosive electrical discharge in the coupling medium in close proximity to the dense material thus developing an electrohydraulic shock wave in the coupling medium. This shock wave is transmitted into the rock or other dense material as an advancing compressive strain pulse which radiates from the explosive electrical discharge through the dense material until it is reflected by a free surface as a tensile strain pulse. The tensile strain pulse is impedance matched with the dense material to be fractured such that the tensile strain pulse induces in situ fracturing of the dense material. A motor driven generator system which provides alternating current to a control unit which incorporates a transformer and diode controlled bridge rectifier system providing stepped up DC voltage. The DC voltage is stored in a capacitor bank and is subsequently discharged through an exploding wire element or spark gap to develop the explosive electrical discharge.

Fluorescent discharge lamp

Abstract: A fluorescent discharge lamp of improved light output having a plurality of phosphor layers stacked on a substrate of a glass tube so that the concentration of activator for the phosphor layer located near the glass substrate is less than that for the phosphor layer located at a position remote from the glass substrate, thereby to form phosphor layer having a low reflection factor to an ultraviolet ray on the electric discharge side, and a phosphor layer of enhanced quantum efficiency and high reflection factor to the ultraviolet ray on the side of the glass substrate The ultraviolet ray generated with an electric discharge is caused to be absorbed as much as possible by the phosphor layers thereby to improve the light output The lamp is used in, for example the field of illumination

Mercury-free discharge lamp

Abstract: An ultraviolet light source includes a volume filled with a dose of AlCl3 and an inert gas. No mercury is used. During electrical discharge excited states of AlCl3, AlCl2, and AlCl emit light, with AlCl having a broad ultraviolet emission peaking at about 261.4 nm. The source may be energized with or without internal electrode. Phosphors may be employed to convert the ultraviolet to visible light. The lamp's envelope may be aluminosilicate coated quartz.

Method and apparatus for operating a gas laser

Abstract: Methods and apparatuses for operating a gas laser which utilize the electrical discharge between the electrodes to increase gas circulation. In a first embodiment, electrical discharges cause a control current (pulse) which activates an electromechanical device disposed within a closed gas flow loop. The electromechanical device acts as a pump and effects gas exchange and heat dissipation with a minimum of elements. In other embodiments, electrical discharges cause pressure fluctuations which increase gas circulation without the use of mechanically moved parts. To this end, connecting lines that determine the direction of the flow are placed between the chambers in order to facilitate equalization of gas pressure. A flow circulation loop is thereby created in a quasi-passive manner when suitably constructed.

Electrode wire for electric discharge machining

Abstract: PURPOSE: To improve the workability and electric discharge machining characteristics, by adding prescribed percentages of Zn, Be and Cu or by further adding a rare earth element. CONSTITUTION: The titled electrode wire consists of 20W50wt% Zn, 0.2W1wt% Be and the balance Cu or further contains 0.5W1wt% rare earth element. The electric discharge characteristics are improved, the strength at high temp. is easily maintained, and the working is facilitated. When the electrode wire is used, the surface state and dimensional accuracy of the resulting machined product are improved. COPYRIGHT: (C)1984,JPO&Japio

Microwave plasma etching device

Abstract: PURPOSE: To contrive to increase the etching speed of a microwave plasma etching device by a method wherein a sample and a sample base are put in a discharge tube, the sample is put at the place on the distance within 30mm in the propagation direction of a microwave from the magnetic flux density maximum point on the axis of the discharge tube, and the diameter of the sample base or a shielding plate is made to 3/4 or more of the inner diameter of the tube. CONSTITUTION: At a microwave plasma etching device, magnetic flux density according to a coil 3 becomes to the maximum in the neighborhood of the tip of a discharge tube 4, and a microwave is absorbed efficiently to form active particles the most. Accordingly, a sample 6 and a sample base 14 are put in the discharge tube, the sample 6 is put at the place of the distance within 300mm from the magnetic flux density maximum point to make active particles to reach the sample to the maximum, the diameter of the base 14 is selected to 3/4 or more of the inner diameter of the discharge tube, or a shielding substance 15 is provided interposing an insulator 16 between them even when the inner diameter is 3/4 or less to reduce the exhaust velocity in the discharge tube, and a pressure rise of electric discharge gas, the increases of concentration of active particles and the number of times of projection are contrived. Moreover, a voltage is applied from the outside independently of the sample and/or the sample base, and moreover the sample is cooled. According to this construction, the etching speed is increased, and mass productivity is enhanced. COPYRIGHT: (C)1985,JPO&Japio

Wire-cut electric discharge machining method using stored machining instructions

Abstract: A method of electric discharge machining using a wire electrode for cutting a workpiece into a commanded shape by producing an electric discharge between the workpiece and the wire electrode and moving the wire electrode relative to the workpiece along a commanded path. The method includes steps of previously storing, in a computer memory, sets of machining conditions which differ depending upon workpiece material and thickness, reading, at the time the workpiece is to be machined, a predetermined set of the machining conditions from the memory in response to a machining condition selection instruction in a machining program and performing electric discharge machining in accordance with the set of machining conditions read from the memory.

Vacuum monitor device and method for vacuum interrupter

Abstract: An abnormally high vacuum pressure of a vacuum interrupter is detected from outside of the interrupter in response to electromagnetic wave signals generated by an electric discharge derived in response to a voltage difference and depending upon Paschen's law. Since the above-mentioned electric discharge is quite different from so-called partial discharge, even when the fixed and movable contacts are closed (i.e., under hot-line condition), it is possible to detect poor vacuum pressure on the basis of the electric discharge existing between the fixed and movable contact rods including two contacts and the main shield, as well as when the two contacts are open. The vacuum monitor according to the present invention comprises a rod or loop antenna fixedly or movably disposed near a conductive material of or connected to the vacuum interrupter and a detection section including, in particular, a 2 to 20 KHz band-pass filter.

Measurement of the rate of ozone formation in an ozonizer

Abstract: The rate of ozone formation in silent electric discharge in oxygen at 1 atm was measured directly by a single-pulse discharge system, which was developed in this work. The time dependence of ozone concentration after a discharge pulse was followed photoelectrically by observing the UV absorption of 254 nm light. The pseudo first-order rate constant, k* = 1.2 x 105 sec—1 , was obtained. It was much lower than the value predicted from the third-order rate constant for the reaction O + 2O2 → O3 + O2 .Various mechanisms were examined to elucidate the results. A possible explanation proposed involves a excited oxygen molecule as a direct precursor to ozone. The rate constant for such a process was estimated.

Wire cut electric discharge machining method

Abstract: PURPOSE:To prevent generation of a residual machined part or deformation of a work when cutting work is performed in the method of wire cut electric dischage machining, by arranging its machining liquid and condition for adhering material susceptible of being accumulated to the work and closing a machined groove then holding a falling part. CONSTITUTION:A work 12 is electric discharge machined by a wire cut electrode 10, then adhering material 24 is acumulated to an end of the work 12 at the side the wire electrode 10 is fed. To increase an accumulated amount of this adhering material, electrolytic action by applied voltage is reduced. That is, such machining conditions are required as increase of specific resistance of machining liquid, decrease of mean machining voltage, increase of capacity of a capacitor in an electric discharge circuit, high frequency of applied voltage, etc. If the accumulated amount of the adhering material 24 is increased to close a machined groove 16, a falling part of the work is held by the adhering material 24, then deformation of the work or generation of a residual machined part can be prevented at completion of machining work.

Supersonic nozzle beam source of atomic oxygen produced by electric discharge heating

Abstract: An atmospheric pressure supersonic nozzle beam source of atomic oxygen is described. Dissociation of molecular oxygen is accomplished by injection into a flow of helium and/or argon which has been heated in a commercial plasma torch. Dissociation efficiencies approaching unity are achieved with beam velocities in the range of 1.5–4.0 km s−1. Production of rare gas metastable and electronically excited oxygen species are minimized by the source design.

Power supply unit for electric discharge machine

Abstract: The present invention relates to a power supply unit for an electric discharge device of the type used in electric discharge machining. First and second DC sources are employed, and the output of the two sources are applied to the machining gap, by way of main and auxiliary switching circuits. The output of the first DC source is applied to the machining gap initially, and a discrimination device operates to detect whether normal electric discharge takes place. The second DC source is applied to the machining gap in dependence upon the operation of the main switching circuit, the operation of which is in turn dependent upon the output of the discrimination circuit and a delay pulse derived from an oscillator which initiates the closure of said auxiliary switching circuit.

Coaxial-type carbon dioxide gas laser oscillator

Abstract: A coaxial-type carbon dioxide gas laser includes an oscillator comprising a gas inlet for introducing gas into a discharge tube through a gas supply chamber having a hollow cylindrical body which serves to disturb the gas flow and orientate the gas toward the discharge tube via a space defined between the discharge tube and the hollow cylindrical body. The gas which has been subjected to an electrical discharge is drawn out of the discharge tube through a chamber and a gas outlet connected therewith. A pair of anode and cathode electrodes are disposed adjacent to the ends of the discharge tube. One of the electrodes is mounted on the gas supply chamber and is annular in shape. The gas supply chamber and the hollow cylindrical body jointly define a gap for passage therethrough of the gas fed from the gas inlet toward the discharge tube via the space. The space is large in cross section than the gap. The discharge tube has an inside cross-sectional area smaller than an outside cross-sectional area and larger than the cross-sectional area of the gap.

Method of controlling wire-cut electric discharge contour machines errors

Abstract: When cutting an arc or a corner in a workpiece on a wire-cut electric discharge machine, discharge power as required on rectilinear cutting is corrected on the basis of the amount of flexing of a wire electrode during rectilinear cutting and an amount of flexing of the wire electrode permitted in view of a tolerance in arc or corner cutting. The tension of the wire electrode is also adjusted and the speed of relative movement between the wire electrode and the workpiece is controlled. Dependent on whether a convex surface or a concave surface is cut in the workpiece, the rate at which the tension of the wire electrode and the speed of relative movement are proportional to each other is changed.

Study of electron waves in electrical discharge channels

Abstract: The fast luminous pulses experimentally observed to propagate in electrical discharge channels, and believed to have a significant role in the process of electrical breakdown, are investigated, using a plasma fluid approach. These pulses fall in two regimes characterized by different average velocities of 106 and 108 m/s. We concentrate on the lower velocity pulses. A nondimensional analysis is used to show that these waves can be considered as longitudinal electron fluid waves driven by electron pressure gradients in weakly ionized plasmas. Model equations are derived considering each additional term in the momentum equation as a small but finite perturbation. In all cases, standard nonlinear fluid model equations are obtained as possible solutions. Electric forces lead to the Korteweg‐deVries equation, viscosity to Burgers equation, and electron‐neutral collisions to a damped wave equation. The propagation and attenuation of fluid waves along preionized channels is naturally associated with the formatio...

Electric circuit with transient voltage doubling for improved operation of a discharge lamp

Abstract: The invention relates to an electric arrangement for operating a an electric discharge lamp (13) which is connected in series with a coil (14) and a switch (15) to a pulsatory direct voltage source. The combination of the lamp and the coil is shunted by a rectifier. The lamp is shunted by a capacitor (18) and the switch is periodically rendered conductive at an instant when the instantaneous voltage of the pulsatory direct voltage source is between 0.5 and 0.8 times the then required re-ignition voltage of the lamp. The voltage build up across the capacitor (18) after the switch has become conducting causes the lamp to reignite. The luminous efficacy of the lamp is comparatively high.

Method and apparatus for separating isotopes using electrophoresis in a discharge

Abstract: A gaseous mixture containing elementary particles (atoms or molecules) of first and second isotopes is exposed to laser radiation at a predetermined frequency to excite elementary particles of the first isotope without substantially exciting elementary particles of the second isotope. An electric discharge is established in the gaseous mixture to produce preferential ionization of elementary particles of the first isotope. Electrophoresis in the discharge (either cataphoresis or the formation of a plasma sheath at the lateral extremity of the discharge) causes preferential migration of elementary particles of the first isotope to a first location and preferential migration of elementary particles of the second isotope to a second location. Portions of the gaseous mixture enriched in the first and second isotopes, respectively, are removed from the respective first and second locations.

Multichannel switch triggered by low‐voltage auxiliary discharges

Abstract: A railgap has been developed which is triggerable by either corona or spark discharges. Trigger voltage and energy were 15 kV and 20 mJ, respectively. The switch was successfully tested over the range 15–35 kV, providing a channel spacing of about 1/cm.

Vacuum monitor for vacuum interrupter and use of the vacuum monitor

Abstract: A vacuum monitor for a vacuum interrupter which can detect a poor vacuum pressure from the outside of the interrupter on the basis of the electromagnetic wave signals generated by the electric discharge existing in accordance with a prebreakdown voltage depending upon Pashen's law when vacuum pressure increases within the vacuum interrupter. Since the above-mentioned electric discharge is quite different from so-called partial discharge, even when the fixed and movable contacts are kept closed (i.e. under hot-like condition), it is possible to detect poor vacuum pressure on the basis of the electric discharge existing between the fixed (8) and movable (9) contact rods including two contacts (10, 13) and the main shield (16), as well as when the two contact are kept opened. The vacuum monitor according to the present invention comprises a rod or loop antenna (21) fixedly or movably disposed near a conductive material of or connected to the vacuum interrupter and a detection section (20) including, in particular, a 2 to 20 kHz band-pass filter (24).

EDM Pulse forming circuit arrangement and method

Abstract: An EDM pulse forming circuit arrangement and method employs an oscillator to produce a succession of quantum signal pulses of a pulse duration τon.q and a pulse interval τoff.q. A gating circuit is used to gate the quantum signal pulses and to turn on and off a power switch in circuit between a DC voltage supply and a gap discharge circuit with the gated quantum signal pulses to develop a train of quantum machining voltage pulses across the machining gap within each time period Ton of the gating pulses. The gap discharge circuit incorporates an impedance such that the quantum voltage pulses of an extremely short duration result in a substantially continuous, unitary and pulsed current flow through the gap within the gated time period Ton, constituting an individual machining electrical discharge of a duration τon which is substantially equal to the time period Ton.

Characteristics of Spark Discharges from Vehicles Energized by AC Electric Fields

Abstract: This study examined certain characteristics of spark discharges from vehicles energized by an electric field. Vehicles were placed in an electric field produced by a 500 kV transmission line. Spark discharges were delivered through a resistor to a driven ground rod. Discharge current and voltage were monitored. These data are analyzed to determine capacitance measured under transient spark conditions and are compared with capacitance determined from 60 Hz measurements. The importance of the vehicle tires is examined. Spark discharge waveforms were also studied using standard high-voltage capacitors for comparison with those discharge waveforms obtained from measurements on the vehicles. The influence of the impedance of the earth return is discussed with reference to differences between the waveforms from the vehicles and the laboratory capacitors.

Electric discharge facsimile recording material

Abstract: A multilayer electric discharge recording material comprising an electrically anisotropic support layer disposed on one surface of a conductive layer and a transfer layer disposed on the other surface of the conductive layer. The transfer layer comprises a material that has a melting point between about 25° and 150° C. and that is capable of melting and adhering to a receiving medium such that a desired pattern or image can be formed and recorded on the receiving sheet.

Electrical discharge propagation in space-charged PMMA

Abstract: A series of controlled experiments using injected electron space charge layers has been used to study discharge propagation. This experimental technique is unique in its ability to investigate discharges where equipotential surfaces are not the major sources of the field but rather space-charge clouds provide the driving force.

Sintering device using electric discharge

Abstract: PURPOSE:To produce a sintered body of uniform and good quality by detecting the change in the state of a sintering powder part by the use of ultrasonic waves, and suitably changing and controlling pressurizing force, conducting electric power, etc. in accordance with the same. CONSTITUTION:First, alloy powder 1 is packed in a molding die 2, and while it is lightly pressurized by operating a lower pressurizing punch 3 with a cylinder 5, pressurizing sintering electric power is supplied from an electric power source circuit 11. At the same, an oscillator 14 is operated to emit ultrasonic waves from a transmitter 13. The ultrasonic waves transmitted through a sintering powder part 1 are received in a receiver 15. The alloy powder 1 is deformed and shrank by the heating with the Joule heat of the conducting electric current and the light pressurizing with the punch 3, whereby its density is increased. The output of the ultrasonic wave intensity detected with the receiver 15 is detected with a level detector 17 via an amplifier 16, and when it attains the prescribed value, a controller 10 opens a changeover valve 8 to operate a cylinder 6 which in turn drives an upper punch 4, and also drives a lower punch 3 simultaneously, thereby exerting the final molding high pressure. This completes molding and sintering.

Electric discharge effects on a XeCl pumped S2 heat‐pipe laser

Abstract: It is shown that an electrical discharge can dissociate the higher‐order sulfur molecules S3→8 into dimers S2 and thus create the proper environment for efficient conversion of XeCl radiation at 308 nm to the blue‐green. The use of a heat‐pipe configuration greatly alleviates the technological problems.