GB1286488A - Eddy current apparatus and method - Google Patents

Eddy current apparatus and method

Info

Publication number
GB1286488A
GB1286488A GB44148/69A GB4414869A GB1286488A GB 1286488 A GB1286488 A GB 1286488A GB 44148/69 A GB44148/69 A GB 44148/69A GB 4414869 A GB4414869 A GB 4414869A GB 1286488 A GB1286488 A GB 1286488A
Authority
GB
United Kingdom
Prior art keywords
field
sept
eddy current
fields
magnetic field
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
GB44148/69A
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Massachusetts Institute of Technology
Original Assignee
Massachusetts Institute of Technology
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Massachusetts Institute of Technology filed Critical Massachusetts Institute of Technology
Publication of GB1286488A publication Critical patent/GB1286488A/en
Expired legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F7/00—Magnets
    • H01F7/06—Electromagnets; Actuators including electromagnets
    • H01F7/20—Electromagnets; Actuators including electromagnets without armatures
    • H01F7/202—Electromagnets for high magnetic field strength
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03C—MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03C1/00—Magnetic separation
    • B03C1/02—Magnetic separation acting directly on the substance being separated
    • B03C1/025—High gradient magnetic separators
    • B03C1/027—High gradient magnetic separators with reciprocating canisters
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03C—MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03C1/00—Magnetic separation
    • B03C1/02—Magnetic separation acting directly on the substance being separated
    • B03C1/025—High gradient magnetic separators
    • B03C1/031—Component parts; Auxiliary operations
    • B03C1/032—Matrix cleaning systems
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03C—MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03C1/00—Magnetic separation
    • B03C1/02—Magnetic separation acting directly on the substance being separated
    • B03C1/025—High gradient magnetic separators
    • B03C1/031—Component parts; Auxiliary operations
    • B03C1/033—Component parts; Auxiliary operations characterised by the magnetic circuit
    • B03C1/0332—Component parts; Auxiliary operations characterised by the magnetic circuit using permanent magnets
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03C—MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03C1/00—Magnetic separation
    • B03C1/02—Magnetic separation acting directly on the substance being separated
    • B03C1/025—High gradient magnetic separators
    • B03C1/031—Component parts; Auxiliary operations
    • B03C1/033—Component parts; Auxiliary operations characterised by the magnetic circuit
    • B03C1/0335—Component parts; Auxiliary operations characterised by the magnetic circuit using coils
    • B03C1/0337—Component parts; Auxiliary operations characterised by the magnetic circuit using coils superconductive
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03C—MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03C1/00—Magnetic separation
    • B03C1/02—Magnetic separation acting directly on the substance being separated
    • B03C1/025—High gradient magnetic separators
    • B03C1/031—Component parts; Auxiliary operations
    • B03C1/033—Component parts; Auxiliary operations characterised by the magnetic circuit
    • B03C1/034—Component parts; Auxiliary operations characterised by the magnetic circuit characterised by the matrix elements
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03C—MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03C1/00—Magnetic separation
    • B03C1/02—Magnetic separation acting directly on the substance being separated
    • B03C1/23—Magnetic separation acting directly on the substance being separated with material carried by oscillating fields; with material carried by travelling fields, e.g. generated by stationary magnetic coils; Eddy-current separators, e.g. sliding ramp
    • B03C1/24—Magnetic separation acting directly on the substance being separated with material carried by oscillating fields; with material carried by travelling fields, e.g. generated by stationary magnetic coils; Eddy-current separators, e.g. sliding ramp with material carried by travelling fields
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N19/00—Investigating materials by mechanical methods
    • G01N19/04—Measuring adhesive force between materials, e.g. of sealing tape, of coating
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
    • G01N27/72—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating magnetic variables
    • G01N27/82—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating magnetic variables for investigating the presence of flaws
    • G01N27/90—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating magnetic variables for investigating the presence of flaws using eddy currents
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03C—MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03C2201/00—Details of magnetic or electrostatic separation
    • B03C2201/18—Magnetic separation whereby the particles are suspended in a liquid

Abstract

1286488 Magnetic separation MASSACHUSETTS INSTITUTE OF TECHNOLOGY 5 Sept 1969 [20 Sept 1968] 44148/69 Heading B2J Eddy current forces are applied to conductive material by means of a first time varying magnetic field having a slow rise time and a second time varying magnetic field having a short rise time. The two fields may be periodic having the same frequency (low sonic) and either #/2 radians ahead or behind each other so as to generate attractive or repulsive forces of maximum magnitude with maximum economy. The first field may be sinusoidal and the second field of square wave or saw tooth shape (Figs. 2 and 5, not shown). The fields are generated by one or two electromagnets. Single or repetitive pulses may be employed (Fig. 5, not shown). The invention may be applied to separating conduction particles from a fluid such as a slurry (Fig. 1, not shown).
GB44148/69A 1968-09-20 1969-09-05 Eddy current apparatus and method Expired GB1286488A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US76104868A 1968-09-20 1968-09-20

Publications (1)

Publication Number Publication Date
GB1286488A true GB1286488A (en) 1972-08-23

Family

ID=25060953

Family Applications (1)

Application Number Title Priority Date Filing Date
GB44148/69A Expired GB1286488A (en) 1968-09-20 1969-09-05 Eddy current apparatus and method

Country Status (2)

Country Link
US (1) US3567026A (en)
GB (1) GB1286488A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8627833B2 (en) 2008-06-24 2014-01-14 Fronius International Gmbh Apparatus and method for cleaning welding torches

Families Citing this family (72)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1816859C2 (en) * 1968-12-24 1971-04-08 Siemens Ag Device for cleaning the boiler feed water from iron oxides
FR2081932B1 (en) * 1970-03-13 1976-09-03 Huber Corp J M
US3757948A (en) * 1971-03-29 1973-09-11 S Tikhonov Filter separator for wet enrichment of finely dispersed materials
US3838773A (en) * 1973-03-16 1974-10-01 Massachusetts Inst Technology Vibrating-matrix magnetic separators
US3873448A (en) * 1973-05-09 1975-03-25 Tenneco Chem Magnetic separator
US3902994A (en) * 1973-05-16 1975-09-02 Emanuel Maxwell High gradient type magnetic separator with continuously moving matrix
US4054513A (en) * 1973-07-10 1977-10-18 English Clays Lovering Pochin & Company Limited Magnetic separation, method and apparatus
GB1488021A (en) * 1974-01-18 1977-10-05 English Clays Lovering Pochin Magnetic separation
US4116829A (en) * 1974-01-18 1978-09-26 English Clays Lovering Pochin & Company Limited Magnetic separation, method and apparatus
US3912634A (en) * 1974-05-01 1975-10-14 Eriez Mfg Co Filter cartridge for a magnetic separator
GB1501396A (en) * 1974-07-19 1978-02-15 English Clays Lovering Pochin Magnetic separators
US4005008A (en) * 1974-08-08 1977-01-25 J. M. Huber Corporation Apparatus for magnetic beneficiation of particle dispersion
US3985646A (en) * 1974-08-08 1976-10-12 J. M. Huber Corporation Method for magnetic beneficiation of particle dispersions
US3984309A (en) * 1974-09-27 1976-10-05 Allen James W Magnetic separator
US4078998A (en) * 1974-10-21 1978-03-14 Robin Roy Oder Magnetic separator
GB1511488A (en) * 1974-11-22 1978-05-17 English Clays Lovering Pochin Magnetic separation
GB1539732A (en) * 1975-04-11 1979-01-31 English Clays Lovering Pochin Magnetic separator
DE2624090C2 (en) * 1975-05-29 1984-01-12 English Clays Lovering Pochin & Co. Ltd., St. Austell, Cornwall Magnetic separator
US4144163A (en) * 1975-06-05 1979-03-13 Sala Magnetics, Inc. Magnetodensity separation method and apparatus
US4046681A (en) * 1975-07-10 1977-09-06 Sala Magnetics, Inc. Multiple matrix assembly and matrix unit for magnetic separator with simplified sealing
US4033864A (en) * 1975-07-16 1977-07-05 Sala Magnetics, Inc. Inlet and outlet apparatus for multiple matrix assembly for magnetic separator and modular matrix and matrix unit
JPS5244465A (en) * 1975-10-06 1977-04-07 Daido Steel Co Ltd Magneic particle separator and production of the same
FR2341347A1 (en) * 1976-02-19 1977-09-16 Commissariat Energie Atomique PROCESS FOR DECLOGING AN ELECTROMAGNETIC FILTER
US4079002A (en) * 1976-04-15 1978-03-14 Aquafine Corporation Thin-section-matrix magnetic separation apparatus and method
DE2628095C3 (en) * 1976-06-23 1981-08-06 Siemens AG, 1000 Berlin und 8000 München Magnetic separation device
US4087358A (en) * 1976-10-12 1978-05-02 J. M. Huber Corporation Augmenting and facilitating flushing in magnetic separation
US4157954A (en) * 1976-10-12 1979-06-12 J. M. Huber Corporation Method for improving production rates during benefication of particle dispersions
JPS5387033A (en) * 1977-01-10 1978-08-01 Etsurou Fujita Method and apparatus for preventing environmental pollution by processing combustible fuel flow in magnetic field
US4157953A (en) * 1977-01-28 1979-06-12 Mawardi Osman K Magnetic separation of iron pyrite from coal
JPS53130572A (en) * 1977-04-05 1978-11-14 Tdk Electronics Co Ltd Highhgradient magnetic separator using amorphous magnetic alloy
US4217213A (en) * 1977-08-26 1980-08-12 Siemens Aktiengesellschaft Device for the separation of minute magnetizable particles, method and apparatus
SE413499B (en) * 1977-10-24 1980-06-02 Boliden Ab PROCEDURES AND AGENTS FOR CHEMICAL PURIFICATION OF WATER WITH SUBSEQUENT MAGNETIC SLIDE SEPARATION
US4265746A (en) * 1977-12-12 1981-05-05 Bon Aqua, Inc. Water treating apparatus and methods
US4265754A (en) * 1977-12-12 1981-05-05 Bon Aqua, Inc. Water treating apparatus and methods
US4208278A (en) * 1978-02-27 1980-06-17 Stekly Zdenek J J Separating chamber for magnetic separator
US4279748A (en) * 1978-03-08 1981-07-21 Inoue-Japax Research Incorporated High-field gradient magnetic separator
FR2449469A1 (en) * 1979-02-23 1980-09-19 Framatome Sa FILTER FOR THE PURIFICATION OF A HIGH PRESSURE AND HIGH TEMPERATURE FLUID CONTAINING FERROMAGNETIC PARTICLES
US4306970A (en) * 1979-04-10 1981-12-22 Ishikawajima-Harima Jukogyo Kabushiki Kaisha Magnetic particle separating device
US4368387A (en) * 1979-05-01 1983-01-11 Magnesep Corporation Method of separating isotopes
DE2929468A1 (en) * 1979-07-20 1981-02-05 Siemens Ag DEVICE FOR HIGH GRADIENT MAGNET SEPARATION
US4244822A (en) * 1979-08-09 1981-01-13 The Babcock & Wilcox Company Industrial technique magnetic apparatus
US4265755A (en) * 1979-08-23 1981-05-05 Bon Aqua, Inc. Magnetic fluid treating unit
US4261815A (en) * 1979-12-31 1981-04-14 Massachusetts Institute Of Technology Magnetic separator and method
EP0032317A3 (en) * 1980-01-15 1981-11-18 A.P.V.-Carlson Limited A method of liquid filtration
US4299701A (en) * 1980-01-25 1981-11-10 Dynaflex Magnetic fluid treating apparatus
NL8000579A (en) * 1980-01-30 1981-09-01 Holec Nv PROCESS FOR CLEANING A HIGH GRADIENT MAGNETIC SEPARATOR AND HIGH GRADIENT MAGNETIC SEPARATOR.
DE3022875A1 (en) * 1980-06-19 1982-01-14 Bayer Ag, 5090 Leverkusen METHOD FOR PRODUCING IRON OXIDE PIGMENTS WITH IMPROVED PURITY AND THE USE THEREOF
DE3039171C2 (en) * 1980-10-16 1985-11-28 Siemens AG, 1000 Berlin und 8000 München Device for separating magnetizable particles according to the principle of high-gradient magnetic separation technology
JPS5817813A (en) * 1981-07-24 1983-02-02 Hitachi Ltd Filter for magnetic separator
DK111582A (en) * 1982-03-12 1983-09-13 Niro Atomizer As HIGH GRADUATE MAGNETIC SEPARATOR
DE3247522A1 (en) * 1982-12-22 1984-06-28 Siemens AG, 1000 Berlin und 8000 München DEVICE OF HIGHLY GRADIENT MAGNETIC SEPARATION TECHNOLOGY FOR DEPOSITING MAGNETIZABLE PARTICLES
US4663029A (en) * 1985-04-08 1987-05-05 Massachusetts Institute Of Technology Method and apparatus for continuous magnetic separation
US4666595A (en) * 1985-09-16 1987-05-19 Coulter Electronics, Inc. Apparatus for acoustically removing particles from a magnetic separation matrix
US4664796A (en) * 1985-09-16 1987-05-12 Coulter Electronics, Inc. Flux diverting flow chamber for high gradient magnetic separation of particles from a liquid medium
US4874508A (en) * 1988-01-19 1989-10-17 Magnetics North, Inc. Magnetic separator
EP0462103A4 (en) * 1989-03-07 1992-07-15 Zimmerman, Patricia W. An improved magnetic-field amplifier
US5200084A (en) * 1990-09-26 1993-04-06 Immunicon Corporation Apparatus and methods for magnetic separation
US6013532A (en) * 1990-09-26 2000-01-11 Immunivest Corporation Methods for magnetic immobilization and manipulation of cells
US5466574A (en) * 1991-03-25 1995-11-14 Immunivest Corporation Apparatus and methods for magnetic separation featuring external magnetic means
US5795470A (en) * 1991-03-25 1998-08-18 Immunivest Corporation Magnetic separation apparatus
US5186827A (en) * 1991-03-25 1993-02-16 Immunicon Corporation Apparatus for magnetic separation featuring external magnetic means
US5227683A (en) * 1992-02-11 1993-07-13 Colonel Clair Magnet assembly with concentrator for providing flux lines perpendicular to fluid flow direction within steel pipe
US5269915A (en) * 1993-04-08 1993-12-14 Colonel Clair Magnetic source and condenser for producing flux perpendicular to gas and liquid flow in ferrous and nonferrous pipes
US5997812A (en) * 1996-06-20 1999-12-07 Coolant Treatment Systems, L.L.C. Methods and apparatus for the application of combined fields to disinfect fluids
US6361749B1 (en) 1998-08-18 2002-03-26 Immunivest Corporation Apparatus and methods for magnetic separation
US20030146813A1 (en) * 2002-02-05 2003-08-07 Thomas Holly Magnet housing
EP1633486A1 (en) * 2003-06-09 2006-03-15 Dow Corning Corporation Magnetic separator apparatus
EP2185289B1 (en) 2007-08-13 2015-02-25 Agency for Science, Technology and Research Microfluidic separation system
EP2683489A4 (en) 2011-03-11 2015-08-12 Guisheng Yang Magnetic particle scavenging device and method
WO2014208770A1 (en) * 2013-06-28 2014-12-31 独立行政法人産業技術総合研究所 Matrix for magnetic separator and magnetic separator
US9387486B2 (en) * 2014-09-30 2016-07-12 Ut-Battelle, Llc High-gradient permanent magnet apparatus and its use in particle collection
US11278915B1 (en) 2018-07-20 2022-03-22 NeoGeneStar LLC Device for capturing and releasing magnetic particles

Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2430157A (en) * 1939-07-29 1947-11-04 Jr William Byrd Magnetic separator for removing finely divided magnetic material from liquids
US2786047A (en) * 1952-02-11 1957-03-19 Phillips Petroleum Co Process for removing nickel catalyst from hydrogenated polybutadiene
GB801003A (en) * 1955-06-24 1958-09-03 Adolf Neidig Filter arrangements
US2954122A (en) * 1957-06-17 1960-09-27 Petroleum Res Corp Method and apparatus for separating materials
US3177408A (en) * 1961-09-18 1965-04-06 Robert G Mills Superconductor solenoid with overheat protective structure and circuitry
NL295761A (en) * 1962-10-02
US3239725A (en) * 1962-12-04 1966-03-08 Ion Phvsics Corp Superconducting device
US3279602A (en) * 1963-02-18 1966-10-18 Al Inc Magnetic separation process and equipment therefor
US3394330A (en) * 1967-01-16 1968-07-23 Rca Corp Superconductive magnet construction

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8627833B2 (en) 2008-06-24 2014-01-14 Fronius International Gmbh Apparatus and method for cleaning welding torches

Also Published As

Publication number Publication date
US3567026A (en) 1971-03-02

Similar Documents

Publication Publication Date Title
GB1286488A (en) Eddy current apparatus and method
US3703958A (en) Eddy current apparatus and method of application to a conductive material
CA924779A (en) Multiple frequency magnetic field technique for differentiating between classes of metal objects
ZA734480B (en) Surveillance system and method utilizing both electrostatic and electromagnetic fields
GB1509394A (en) Linear induction motor stator systems and the use thereof
GB1271328A (en) Apparatus for orientation of non-magnetic electrically conductive bodies, by a magnetic field
GB563333A (en) Improvements in magnetic work holders separators or the like
GB1357906A (en) Transmitter terminal
GB1322229A (en) Method and apparatus for separating magnetic material
GB1507137A (en) Magnetic bubble translation system
JPS57159025A (en) Method and device for dry etching
ES8607063A1 (en) Method and apparatus for the electrostatic flocking of material having an endless or yarn configuration.
GB1359503A (en) Handling and sorting devices
GB1096578A (en) Electrical positioning device
AU7215074A (en) Generating linear electromagnetic travelling fields
GB1010501A (en) Permanent magnet assembly
SU509907A1 (en) Sorting method of magnetic contacts
SU933114A1 (en) Electrodynamic separating method
GB845712A (en) Improvements in or relating to the detection of ferrous particles in non-ferrous electric conductors
GB1265227A (en)
GB1439175A (en) Permanent magnetic separators
SU1200698A1 (en) Apparatus for analog sampling of particles with predetermined pulse
CA1003787A (en) Shielded, adustable depth minute particle stratifier
GB1231133A (en)
FR2057446A5 (en) Magnetic sepn of weakly magnetic ores and - materials using a ferromagnetic material

Legal Events

Date Code Title Description
PS Patent sealed [section 19, patents act 1949]
PE20 Patent expired after termination of 20 years