Ac Plus Dc Patents (Class 204/DIG8)
  • Patent number: 5496458
    Abstract: An electromagnetic enriching device for electrolytes that are passed through a tubular cathode electrode that coaxially houses a sacrificial anode member. The electrolyte enters a housing containing the tubular cathode member and passes through an electric field established between the anode member and the tubular cathode member. Varying and alternating electromagnetic field is created by a coil wound over the cathode tubular member in order to interfere with the cations leaving the sacrificed anode member. In the manner, the device can be connected to a source of water, applying an electrolyte conditioner and resulting in an enriched water that will be applied to plants that require a particular nutrient. The anode member will be selected depending on the nutrient needed by the plant.
    Type: Grant
    Filed: May 12, 1995
    Date of Patent: March 5, 1996
    Inventor: Ricardo Roch
  • Patent number: 5324399
    Abstract: A method and system for monitoring the quality of a phosphate coating on a metal surface having a large surface area. The method comprises applying a current or potential between the metal surface and one or more counter electrodes while they are in the phosphating solution and superimposing a constant ac signal thereon. An ac impedance spectra is obtained by measuring the ac potential between the metal substrate and one or more reference electrodes located between the counter electrode and the substrate. The ac impedance spectra provide an indication of defects in the phosphate coating even when the defects are located within a relatively small region of the total surface area of the metal surface.
    Type: Grant
    Filed: May 12, 1992
    Date of Patent: June 28, 1994
    Assignee: Hughes Aircraft Company
    Inventors: Frank A. Ludwig, Bruce M. Eliash
  • Patent number: 5304298
    Abstract: A process for roughening aluminum or aluminum alloys useful as support material for printing plates, in which process two electrochemical roughening steps are carried out in direct succession and are followed by a pickling step. Printing plates are produced from this support material by coating with light-sensitive coatings, which printing plates, when exposed and developed, give corresponding printing formes of very uniform topography, high run stability and good damping agent supply.
    Type: Grant
    Filed: September 1, 1992
    Date of Patent: April 19, 1994
    Assignee: Hoechst Aktiengesellschaft
    Inventor: Michael Brenk
  • Patent number: 5298131
    Abstract: A method of monitoring in-tank and on-line metal ion content within a plating bath. The method involves the steps of applying a pretreatment signal to a sensing electrode positioned within the plating bath, applying a sweep signal to the pretreated sensing electrode, and measuring the voltammetric peak current of the resultant response signal. The voltammetric peak current is proportional to the metal ion content of the plating bath. The method complements and is easily integrated with known voltammetric techniques for analysis of trace and major constituents, and is thus an integral part of an efficient overall plating bath analysis system.
    Type: Grant
    Filed: May 28, 1993
    Date of Patent: March 29, 1994
    Assignee: Hughes Aircraft Company
    Inventors: Bruce M. Eliash, Frank A. Ludwig, Nguyet H. Phan, Vilambi N. Reddy
  • Patent number: 5106468
    Abstract: For the electrophoretic separation of a dispersed phase or contaminant (solid, liquid, or gaseous) from a continuous liquid phase under conditions of intrinsic ionic conductivity due to intrinsic bipolar ions in the continuous phase, especially for conductivities of the continuous liquid phase in excess of about 10.sup.-8 (.OMEGA..m).sup.-1 for which known electrofiltration processes are relatively ineffective or unworkable, a voltage is applied to the dispersed phase-containing liquid phase. The dispersed phase has a field-dependent mobility, and the applied voltage is such as to establish, within the liquid to be treated, a periodic asymmetric electric field E(t), conveniently comprising alternate positive and negative rectangular pulses, having the properties that the time-averaged amplitude of E(t) over one complete period, T, is zero but the average amplitude of each positive feature of the periodic waveform is unequal to that of each negative feature.
    Type: Grant
    Filed: December 30, 1985
    Date of Patent: April 21, 1992
    Assignee: Exxon Research and Engineering Company
    Inventor: Robert J. L. Chimenti
  • Patent number: 4919774
    Abstract: A method of continuously electrolytically treating a metal web in an electrolytic liquid using an alternating waveform current via a pair of main electrodes such that the surface of the metal web experiences both an anode reaction and a cathode reaction. The ratio of the current value contributing to the anode reaction acting on the surface of the metal web and the current value of the cathode reaction acting on the surface of the metal web is controlled by shunting a portion of the supplied current to an auxiliary electrode, which is separated from the main electrodes, as a direct current.
    Type: Grant
    Filed: August 22, 1988
    Date of Patent: April 24, 1990
    Assignee: Fuji Photo Film Co., Ltd.
    Inventors: Shinichiro Minato, Atsuo Nishino
  • Patent number: 4875983
    Abstract: In the continuous electrodeposition of chromium metal and chromium oxide on metal surfaces the codeposition of chromium and its oxide, inert and insoluble, is obtained from the same bath and at high current density, by using a number of cycles of impressed cathodic current and defined ranges of electrolyte velocities in the deposition cell. In this manner a product is obtained wherein a specific quantitative relationship between chromium metal and chromium oxide ensures corrosion resistance superior to that obtainable in known products.
    Type: Grant
    Filed: May 17, 1988
    Date of Patent: October 24, 1989
    Assignee: Centro Sviluppo Materiali SpA
    Inventors: Santa Alota, Vincenzo Ferrari, Massimo Memmi, Leonardo Pacelli, Susanna Ramundo
  • Patent number: 4798656
    Abstract: In processes for electrolytically dyeing anodic oxide layers on aluminum or aluminum alloys with direct or alternating current in electrolytes containing metal salts, high requirements are imposed on the uniformity of the dyeing and on the dyeing rate. The improvement of the uniformity of the dyeing and an increased dyeing rate can be achieved by pretreating the oxide layer by means of asymmetric alternating current before it is dyed. Such a process is preferably used in combination with an Sn-containing electrolyte.
    Type: Grant
    Filed: January 12, 1988
    Date of Patent: January 17, 1989
    Assignee: Swiss Aluminium Ltd.
    Inventor: Jean-Francois Paulet
  • Patent number: 4704196
    Abstract: A process for the surface treatment of carbon fiber tows each consisting of a multiplicity of filaments, comprises treating the tows by electrolytic oxidation, using each tow as a positive electrode and applying an electric current in the form of pulses. The pulse spacing is such that the electric supply and non-supply durations are 0.02-20 sec. each, preferably 0.1-5 seconds each. The pulse shape is rectangular, triangular, or sine waves. The applied voltage is 3-15 V and the current density 0.2-1000 A/m.sup.2, preferably 1-100 A/m.sup.2, more preferably 5-20 A/m.sup.2. The electrolyte is an aqueous solution of an oxidizing agent, strong acid or base, neutral salt, or weak acid or base.
    Type: Grant
    Filed: November 17, 1986
    Date of Patent: November 3, 1987
    Assignee: Toa Nenryo Kogyo Kabushiki Kaisha
    Inventors: Makoto Saito, Hiroshi Inoue, Noboru Yamamoto
  • Patent number: 4622302
    Abstract: A device and process for inducing membrane fusion under an electric field. The process comprises the steps of (a) suspending said membranes in an aqueous buffered medium in a manner so that the membranes are without contact with each other; (b) altering said membranes to a fusogenic state by applying 2-30 pulses of direct current at a rate of 2 to 5 pulses per second in an electrical field strength of about 500-1000 volts/mm in the medium, said pulses having a rapid rise time not exceeding about 10 micro seconds and an exponential decay half time of about 0.2 milliseconds to about 1.2 milliseconds; and (c) thereafter bringing said fusogenic membranes in contact with each other. A long-lived metastable fusogenic state of membranes can be obtained by the device and process.
    Type: Grant
    Filed: August 9, 1984
    Date of Patent: November 11, 1986
    Assignee: American National Red Cross
    Inventor: Arthur E. Sowers
  • Patent number: 4482444
    Abstract: This invention pertains to a process for electrochemically modifying electrochemically roughened aluminum or aluminum alloy-based support materials for printing plates. An aluminum or aluminum alloy-based support material is electrochemically roughened using alternating current in an electrolyte containing at least one from the group consisting of hydrochloric acid and nitric acid. Subsequently, at least one surface of the material is treated in an aqueous electrolyte, with the roughened material being made the cathode. The cathodic treatment results in removal of material from the surface in the order of from 0.1 to 10 g/m.sup.2, and is carried out in an aqueous electrolyte which has a pH value in the range from 3 to 11 and includes at least one water-soluble salt in a concentration ranging from 5 g/l up to the saturation limit thereof. The cathodic treatment is appropriately conducted using direct current at a current density from 3 to 100 A/dm.sup.2, at a temperature from to C.
    Type: Grant
    Filed: June 16, 1983
    Date of Patent: November 13, 1984
    Assignee: Hoechst Aktiengesellschaft
    Inventors: Werner Frass, Dieter Mohr
  • Patent number: 4457221
    Abstract: A process and apparatus for killing organisms in situ within a host by means of successive short-duration high-current-density pulses of electricity of alternately opposite polarity. These pulses are passed through the host and concomitantly the organisms for a period of a few seconds. The cellular structure of the host is not destroyed, nor is the temperature thereof appreciably elevated. The current is conveyed to the host from electrodes immersed with the host in a weak electrolyte. The pulses are formed by phase-controlled thyristors.
    Type: Grant
    Filed: August 8, 1983
    Date of Patent: July 3, 1984
    Inventor: David K. Geren
  • Patent number: 4437955
    Abstract: Aluminum foil exhibiting a good combination of capacitance and mechanical strength is produced by an etching procedure that includes the steps of AC pre-etching aluminum foil in an acid bath containing hydrochloric acid and then, without removing the hydrochloric acid from the foil, etching the foil with a high density DC while the foil is immersed in an aqueous solution of sodium chloride and sodium sulfate.
    Type: Grant
    Filed: July 5, 1983
    Date of Patent: March 20, 1984
    Assignee: U.S. Philips Corporation
    Inventor: Jesse S. Shaffer
  • Patent number: 4363861
    Abstract: The present invention provides a developing method for rendering a latent image supported on an image bearing member visible, and an apparatus therefor, in which a developer supporting member supporting thereon spherical granular developer prepared in substantially spherical form by a flow coater process or a spray drying process is maintained in opposed relation to an electrostatic image bearing member having a backing electrode so that the surface of the image bearing member and the developer on the developer supporting member are maintained in a mutually contact-free state, and an alternating voltage is applied to the developer supporting member to cause reciprocating motion of the developer in the developing area between the developer supporting member and the image bearing member.
    Type: Grant
    Filed: February 26, 1980
    Date of Patent: December 14, 1982
    Assignee: Canon Kabushiki Kaisha
    Inventors: Shunji Nakamura, Junichiro Kanbe, Tsutomu Toyono, Tohru Takahashi, Yasuyuki Tamura
  • Patent number: 4236992
    Abstract: A novel electrode, an apparatus and a method are set out for electrolyzing a chloride ion containing aqueous solution to produce chlorine and ozone. Through utilization of a solid state rectifier network, and without the use of a transformer, full line voltage, after rectification, is applied between the anode and cathode of an electrolytic cell utilizing an anode which is a laminated body of a platinum group metal foil bonded to a tantalum or niobium layer which in turn is bonded to a titanium substrate. Chlorine and ozone production is quite rapid.
    Type: Grant
    Filed: August 6, 1979
    Date of Patent: December 2, 1980
    Inventor: Constantinos D. Themy
  • Patent number: 4233132
    Abstract: Electrodes are immersed within oil which forms a layer over a quantity of water. When current is passed between the electrodes which are held to a predetermined gap from the interstitial surface between the oil and water, water is caused to undergo electrodecomposition. Gaseous hydrogen is then recovered in the sealed space above the oil-water layers and the oxygen is caused to react with constituents in the oil layer.Consequently, there is produced continuously a quantity of hydrogen which is separately collected and is usable in gaseous form.
    Type: Grant
    Filed: March 19, 1979
    Date of Patent: November 11, 1980
    Inventors: Randall Carr, L. E. Geoffroy, Rodger H. Flagg, Donald L. Carr
  • Patent number: 4226680
    Abstract: A continuous length of aluminum is anodized during passage through an anodizing electrolyte and then colored during passage through an inorganic coloring electrolyte, in which a counterelectrode is immersed. In the electrolytic coloring stage alternating current with a superimposed D.C. compound is preferably passed between the anodized aluminum and the counterelectrode when the electrolyte is appropriate for such treatment. The alternating current circuit for the electrolytic coloring stage is preferably completed via an electrode immersed in the anodizing electrolyte at a position facing substantially unanodized aluminum so as to effect a liquid contact.
    Type: Grant
    Filed: June 6, 1977
    Date of Patent: October 7, 1980
    Assignee: Alcan Research and Development Limited
    Inventors: William E. Cooke, Robert A. Innes
  • Patent number: 4133725
    Abstract: A process for hard anodizing of aluminum and aluminum alloys by use of a low voltage having a DC component and a superimposed AC component. The electrolyte can have relatively low acid concentration and can be of higher temperature than usually employed for hard anodizing.
    Type: Grant
    Filed: May 18, 1978
    Date of Patent: January 9, 1979
    Assignee: Sanford Process Corporation
    Inventors: Moisey M. Lerner, James H. Morse
  • Patent number: 4113587
    Abstract: In a method for electrochemical machining effected by disposing a work blank and a cathode opposite each other across a gap in an electrolyte and causing a flow of electric current to pass between said work blank and cathode, an improvement is disclosed which consists in using, as the electric current, a pulsating electric current having a pulse width of from 0.01 to 10 ms and a duty factor of not more than 0.5. Use of the pulsating electric current of the foregoing description in place of direct current enables the desired machining to be accomplished effectively on the work blank without involving any forced movement of the electrolyte.
    Type: Grant
    Filed: September 12, 1977
    Date of Patent: September 12, 1978
    Assignee: Agency of Industrial Science and Technology
    Inventor: Kunio Chikamori
  • Patent number: 4110190
    Abstract: Apparatus for etching fine grooves in surfaces by the combination of pulsed currents in a modified Electro-Chemical Machining method in combination with a flow guiding template.The apparatus is very suitable for the etching of grooves in a surface used in a bearing.
    Type: Grant
    Filed: December 7, 1977
    Date of Patent: August 29, 1978
    Assignee: Ultra Centrifuge Nederland N.V.
    Inventor: Kommer Visser
  • Patent number: 4048048
    Abstract: Synchronous plating techniques for reducing adjacent bit disturb charactetics or interactions in a magnetic memory wire include the step of sinusoidally and smoothly depositing the magnetic layer on the outer surface of the wire so as to increase the effective magnetic path length between adjacent bits. The resultant wire has changing cross-sectional dimensions corresponding to the varying sinusoidal configuration of the wire.This invention concerns a film-plated memory wire of improved characteristics and the method of making the same. The term "memory wire" is used to designate a magnetic recording and reproducing element for recording or reproducing magnetic signals by magnetic flat interlinkage with a magnetic transducer head during relative motion of the wire and head.
    Type: Grant
    Filed: April 7, 1976
    Date of Patent: September 13, 1977
    Assignee: The United States of America as represented by the Secretary of the Navy
    Inventors: Charles Bennett, Emil Toledo
  • Patent number: 4026781
    Abstract: An anodizing system uses both positive and negative current pulses. Such pulses are adjustable to achieve different adjusted values of positive and negative currents. These values are sensed and used to maintain automatically such values. The ratio of negative current to positive current is preferably greater than 3% for the production of relatively thick, dyeable, hard anodized coatings and conventional (normal) anodic coatings of light shades of integral colors using a simple sulfuric acid bath which may be maintained at relatively high temperatures. Current may be applied at nearly full current density initially without burning. In some cases, additional means may be provided to increase the throwing power by eliminating the negative current and using means such as capacitors or inductors to prolong the decay of the positive pulses, preferably such that the then composite positive pulses are maintained above a zero value.
    Type: Grant
    Filed: March 28, 1972
    Date of Patent: May 31, 1977
    Assignee: Scionics of California Inc.
    Inventors: Frederick S. Newman, John R. Thorne, John T. Hartman
  • Patent number: 4009091
    Abstract: A pulse plating system wherein the duty cycle is controlled by skipping pulses in producing the output signal. The circuitry for controlling the skipping of the pulses can either be analog or digital type circuitry.
    Type: Grant
    Filed: April 27, 1976
    Date of Patent: February 22, 1977
    Assignee: Instrumentation & Control Systems, Inc.
    Inventors: Harold Washington, Martin Kozi
  • Patent number: 3959088
    Abstract: An a-c source of power is utilized to provide periodic d-c pulses of predrmined amplitude, duration, and frequency by synchronizing the delay sweep of a cathode ray oscilloscope with the sine wave of the a-c voltage input, timing the delay sweep to provide an output signal at the desired frequency and at the particular point on the sine wave which will impart the desired voltage peak thereto, and utilizing each output signal to trigger a first silicon controlled rectifier for initiating a current pulse while simultaneously providing a corresponding signal with a given delay for firing a second silicon controlled rectifier to terminate the current pulse and establish the duration desired thereof.
    Type: Grant
    Filed: March 19, 1975
    Date of Patent: May 25, 1976
    Assignee: The United States of America as represented by the Secretary of the Army
    Inventor: William C. Sullivan
  • Patent number: RE31901
    Abstract: A process for electrolytically treating aluminum or its alloys in the form of a strip, wire or foil material in a continuous manner which comprises continuously passing the material through an anodic oxidation treatment cell through which a direct current, alternating current or AC-superimposed direct current is caused to flow and an electrolytic coloring cell through which an alternating current or AC-superimposed direct current is caused to flow and carrying out electrolysis in both said cells to anodize and color the material in a continuous manner.
    Type: Grant
    Filed: June 24, 1981
    Date of Patent: May 28, 1985
    Assignees: Pilot Man-Nen-Hitsu Kabushiki Kaisha, Toyo Giken Kogyo Kabushiki Kaisha
    Inventors: Satoshi Kawai, Yoichi Yamagiwa, Masashi Mizusawa, Hiroshi Watanabe, Yoshio Ando, Masaaki Takahashi