Патент USA US2403424код для вставки
July 2, 1946- v 1'.v 'ZUSCHLAG I 2,403,424 DEMAGNETI Z ING APPARATUS Filed NOV. 1, 1943 I I ~ ' INVENTORQ' 55' > BY m lbw, ' MM A TTORNE Y5. 2,4®3,424 Pateuled July 2, STATES PATENT’ QFFECE ZAGSBAM DEMAGNETIZING APPARATUS Theodore Zusclilag, West Englcwood, N. JL, as signor to ‘Magnetic Analysis Corporation, Long Island City, N. ‘iii, a corporation of New York Apolication November 1, 134:3, Serial No. 508,525 4 Claims. (Gil l‘l'5-—-ill1) 2 ‘i This invention relates to the demagnetization oi magnetic bodies and is directedespecially to improvements in demagnctiaing apparatus. The ages available from a wide range of line voltages, without the use of additional booster, or step-up, transformers and without changing any of the coils in the demagnetizing system itself. Thus, the demagnetizing apparatus, in accordance with this invention is useful without structural change at practically any location, and it also permits the demagnetization of bodies more heavily mag invention is an improvement, for example, on the systems and apparatus disclosed in my United States Letters Patent No. 2,267,392, granmd July" 0 "3413, and No. $355,940, granted August 15, it“, this application being ?led as a continua ticn-in-part of the application which matured noticed or oi greater retentivity, as well as pro viding improved e?ciency and more exact and rapid demagnetization of bodies having low re sidual. magnetism. The invention thus provides to o the last-named patent. Products manufactured of magnetic materials such as iron and steel are susceptible to roag~ v appar t s at once more simple to operate, more nctization, and such magnetization in many cases ' universally useful, and more economical in use, interferes with their satisfactory use. While this true of articles of any shape it is particularly no L than that heretofore known. The apparatus of the present invention is il true of elongated steel and iron products such as lustrated in the drawing, in which is shown an rods, bars and tubes“ , alternating current supply 5 of, say, 120 volts ‘The unavoidable or inadvertent magnetization oi”- connnercial frequency, such as 60 cycles, which oi’ steel or similar products sometimes results as is couriectilile through a line switch 2 to the de the natural consequence oi normal manufacture magnetizing system shown above. This system includes an C. (alternating-current) energiz~ lug flue-rice orocesses the arrangement which, mechanically of moleculesaffect in theorloody lug coil the terminals of which are connected or product, or, again, as a consequence oi‘ the to the source of A. 53. current which, for con action of the product to one or more mag“ 25 venience, may be considered as the line switch 2. netic ‘fields at a stage in the process when ‘H This cell should normally be of suf?cient react» material, thereof is comparatively fluid and time once to permit direct connection across the power susceptible to the in?uence of magnetic ” “‘ line at the prescribed voltage. In the particular embodiment of: the invention here described this coil comprise approximately 860 turns wound diameter large enough to allow the body ll, which is to be demagcetized, to be placed within it to be passed through it, depending upon the Such magnetic fields may, for example, cot. ’ the normal magnetic ?eld of the o“ are tiiiclal ?elds set up ‘lily electrical circuits or a, ‘ in the neighborhood, or a combination 5’ . ’ products, to on lost them det 35 a ' t sir pnysical or allui teristics such, for e: the existence of strains or flaws, of; such testing steel products are tiirougii of the body. Preferably connected in *s with energizing coil is a condenser ‘Ell , ed to a capacity value such as to resonate ' ‘ icing coil 3 at the applied line frequem e assumed case, 60 cycles, By thus tun , ez'iergizing approximately circuit, to which the frequency includes of coilthe electromagnetic likely to leave a certain degree the 5 current, a considerable gain in our’ resle l. or like products it is usually do traces of such residual magi or removed the material is slug: is mill. Although such undesired resin 'isiri mayinreadily my mentioned lee r'rnoved patents, in the t'losc e t, hence in the strength of the energizing is simply and economically achieved. across condenser is a “bleederw re“ of a resistance suitable to permit the “ y-rge oi condenser ill. The secondary, neutralising, coil 5 is disposed in inductive re lation to coil ll so as to be also in inductive re lation. to the body to ‘be demagnetized. To this have certain inherent limitations which iii? end, soil it should preferably be wound outside of coil positioned to be concentric with coil ourpose oi’ the present invention to over-l. like. the particular embodiment referred to, sec ondary coil 5 may be of about 2,000 turns, and “o oresent invention. makes possible a cone of much ilitier wire than that with which the sideralcla enlargement of the range of “oath the coil 3 is wound. Coils 3 and 5 together alternating-cui“rent and the direct-current vol‘w 2,403,424 3 may preferably be constructed as a unitary coil assembly of the air-core type, of which coil 5 comprises not only the secondary of an alternat ‘mg-current transformer (coil 3 being the pri 4 lishing the indicated polarities at the respective terminals of. the resistor. Filter condenser l5 tends to smooth out the pulsations so as to keep the potential difference of the mentioned termi mary) , but in addition performs the function of a D. C. (direct-current) neutralizing coil, as will nals substantially constant. Manipulation of the coarse adjustment i5 and be explained below. the fine adjustment ll of the potentiometer H . As shown in the drawing, a polarizing or re permits the very accurate control of the negative versing switch 6 is connected across the terminals bias potential applied to grid H with respect to of coil 5 so that the direct-current polarity of coil 10 the cathode 9 of tube 1, over a wide range. By 5 may be selected as required. The two pairs of this means, in combination with the selection of contacts of this reversing switch are connected, polarity achieved by reversing switch 6, there respectively, to the anode 8 and cathode 9 of a may be established a uni-directional current in triode recti?er tube 1. This tube may be of type coil 5 of such magnitude and direction as to cre 2A3 or 6A3, for example. Serially connected in 15 ate a uni-directional electromagnetic ?eld exactly the lead between switch 6 and cathode 8 is a equal in intensity and opposite in sign to the re switch I! the purpose of which will be described sultant ?eld created in the neighborhood of body later. I by all extraneous magnetic forces acting on that A diode recti?er tube I2 is connected to the ter body. The A. C. ?eld of coil 3 acting in conjunc minals of the A. C. current source 2 to furnish 20 tion with this D. C. ?eld thus reduces the residual an adjustable control potential to the control magnetism in the body to an extremely low value, grid of half-wave recti?er tube 1. To this end the or substantially to zero. cathode“ of diode I2 is connected to one ter As above explained, coil 5 functions as a sec minal ot the A. C. voltage source 2 and the anode ondary of transformer 3, 5 supplying alternating2| of diode I2 is connected in series with a re current potential to recti?er l, and through this sistor H to the other terminal of source 2. The same coil 5 ?ows no appreciable alternating cur resistance value of resistor l4 may be about 2,000 rent, ‘but only recti?ed current produced by recti ohms. A ?lter condenser l5, of say 25 micro ?er 1. The alternating-current potential induced farads, may be shunted across the terminals of in coil 5, being impressed across the anode and resistor H, as shown. In the embodiment illus 30 cathode of recti?er 1, produces a flow of current trated, resistor I4 is used as a potentiometer and in the circuit including coil 5 when the alternating has two adjustments, one of which is a switch potential renders the anode positive with respect l5 selectively connectible to a plurality of taps to the cathode but not when it renders the anode on the resistor for coarse voltage adjustment, and negative with respect to the cathode. rl'hus the an adjustable slider I’! on the resistor for ?ne recti?er “passes” either one half or the other half voltage adjustment. The resistor I‘ need not of the cycles, depending upon the position of comprise a single element as shown in the drawj switch 6. The recti?ed Zill‘l‘lut ?owing; in coil 5 ing. but may conveniently comprise a rheostat actually comprises a succession of uni-dint‘, it . type resistor provided with taps cooperating with current peaks occurring at the frequency of the a selector switch 16, and connected in series with 40 current in power line I. Although this recti?ed a potentiometer type resistor having an adjust current is therefore not actually a continuous able slider l‘l. I'he ?laments or cathode heaters direct current the effect of it is to produce a polar~ l0 and I3, respectively, of the tubes should, as is iZecl or uni-directional ?eld about coil 5; and for well known in the art, be connected to suitable the purpose of the present invention such a ?eld secondary windings of a ?lament-heating trans 45 is equivalent to one produced by a continuous former, the primary of which should be connected direct current. to the current source 2. From the foregoing it will be evident that since The operation of this system is as follows: The the energy source for the recti?er circuit is coil closing of line switch 2 causes alternating current 3 which is also the source of ‘the alternating de at the line frequency to flow through energizing 50 magnetizing ?eld, any change or variation in this coil 3. The value of this current is economically demagnetizing ?eld, or in the current of the cir increased by reason of the resonance, or approach cuit of coil 3, will automatically result in a cor to resonance, produced by variable condenser 20 responding change or variation in the unidirec in combination with the inductance of coil 3. tional neutralizing ?eld, so that the relative Thus, an A. C. energizing ?eld of considerable strength of the two ?elds remains the same even strength is produced by coil 3. It is important though variations occur in the circuit of coil 3 that the strength of this ?eld be sufficient to ef which causes variations in the demagnetizing fect rapid demagnetization, but it is unimportant if the ?eld is stronger than necessary. Coil 5, being electromagnetically coupled to coil 3 and preferably arranged to be symmetrically spaced in relation thereto, acts as a secondary with re— spect to coil 3 by reason of which an alternating potential will be developed across secondary coil 5. Due to the unilateral conducting property of recti?er ‘I this alternating potential causes a uni directional pulsating current to ?ow through the recti?er circuit traced from coil 5 to switch 6, anode 8 of tube 1, cathode 9 thereof, switch l8, switch 6, and back again tocoil 5. This coil 5, 70 being disposable in electromagnetic relation to the body I, also functions as a neutralizing coil. The connection of resistor M in series with recti?er l2 across the power line creates uni-directional current flow through resistor I4, thereby estab ?eld. For example, it frequently happens that, as the body under treatment moves simultane ously through the ?elds of coils 3 and 5, struc tural or metallurgical variations in the body re act magnetically on coil 3 to produce changes in the magnitude of current in the coil and hence in the strength of its ?eld, and if the recti?er circuit were coupled independently to an energy source the neutralizing ?eld would remain con stant while the demagnetizing ?eld varied. This is a serious disadvantage in clemagnetizing equip ment for the present purpose, and is here ob viated by deriving the energy for the recti?er cir cuit solely from the coil which generates the de rnagnetizing held (the electron energy from cath ode Hl being disregarded). Similarly, when the voltage of the power line I fluctuates, relative strength of the alternating-current and direct ‘2,403,424 body movable with respect to said apparatus, the current?elds with respect to the‘body ‘will re. combination which includes a demagnetizing coil main‘substantially constant, ?rst, for the rea-- connectible to a source of alternating current, . said coil being disposable in inductive relation ‘to son above described, and ,- second, because the' control‘ potential applied to grid H of ‘recti?er tube ‘I is derived directly from recti?er I: which , in'turii is energized by the ‘same alternating 01.11‘: l’rent source. The relative strength of the .A, C. 'and D. C. ?elds ‘can, of course, always be adjusted by means of tap switch IS, in conjunction with ?ner adjustment I1. ' The demagnetizingprocess ' 5 said body, a neutralizing coilinductively related‘ . to said demagnetizing coil and disposable in in-- _ ductive relation to said body, a recti?er tube having any anode, acontrol‘ grid and a cathode, / said coils being positioned to be in inductive rela 10 tion simultaneously to the same portion of said best be carried ,. - body as said body moves with respect to said - ‘out in three stages. _ The ?rst stage requires ' coils. a recti?er circuit for producing unidirec tional neutralizi'ngcurrent in said neutralizing merely the placingof a magnetization meter near -coil,isaid circuit includingsaid neutralizing coil the body and observing the de?ection of. the “ ‘meter to determine whether‘and to what degree _1_5_ and a half-wave recti?er including the anode and cathode of said tube, said circuit being cou the body under observation is magnetized. \Meters pled to; said source only by means of said induc , suitable for this purpose and'methods for using tive relation tolsaid demagnetizing coil, where-' , them are described in more detail in my men-: tioned patent. If the body is not magnetized, . by changes in the magnitude of alternating cur rent in said. demagnetizin'g coil resulting from nothing-further needbeuone to that particular 0 variations in, the magnetic effect of said bodyv body .or no on thereof." However, it the mag-l ' netization meter vindicates a de?ection, the body; is moved slowly through or past the coils 3 and 5,‘ - ‘ on‘ said demagnetizing coil as said body passes throughthe ‘?eld thereof automatically produce corresponding changes in said unidirectional cur-q at say a speed-of 100 feet per'minute, with only’ ‘the energizing coil '3v energized. This may be 5, rent insaid neutralizing'coil, a second recti?er, accomplished by setting-the switch [8' in its open ; a resistor connected in series with said second recti?er-f across said source, connections from the circuit position. The direction of de?ection of cathode and control grid of said half-wave rec the magnetization meter at ‘this ‘stage will fur nish a guide as to the direction ‘in which the re- -' ti?er tubevto said resistor, whereby a bias poten The 30' tial derived from the second recti?er is impressed, ‘ third stage of operationoomprises passing the\ » on said control grid, and‘, means for adjusting . body again through the apparatus with power - ‘said bias potential. - versing switch 6 should-then be thrown. supplied to both the energizing coil 3 and the i ' neutralizing coil 5 ‘by closing switch I8 and ad- ' 2. In apparatus for demagnetizing a magnetic body, the combination which includes a demag justing tap switch l6 and ?ner adjustment I1’ 35 netizing col-l connectible to a source of alternat ing current,.said coil being disposable in'induc until the magnetization meter reads zero. Under ' tive relation to said body, a'neutralizing coil in some circumstances, as for example when the body 4 is of fairly small size, the grld‘bias avail- 1 ductively related to said‘ demagnetizing coil and disposable in inductiverelation to said body, said ‘ able through controls l6 and I] may be ‘suf ?cient to block entirely the output current from ‘49 cells being positioned to be in inductive relation simultaneously to the same portion of said body, tube 1. In such event the switch It may remain ‘ closed during the entire operation, if desired. _ a recti?er tube'having, an anode, a control grid Should a neutralizing ?eld of greater strength - and a cathode, a recti?er circuit for producing unidirectional neutralizing current in said neu-. i than that provided by a~single triode' recti?er ; tube of the types above mentioned be required, 45 'tralizing coil, said circuit including said rieu~ 1 two or more such tubes may be connected in par allel, or a grid-controlled recti?er tube‘of greater output may bevsubstituted. The power required to furnish the bias potential for the control of the output of tube ‘I being negligible, diode.“ 50 may be of any convenient type, that commonly designated as type 5Y3 having been found satis factory. Furthermore, a copper-oxide or‘ other f‘ type‘ of recti?er can be substituted with equal 55 From the foregoing‘ description of a‘ preferred success.‘ - - . I embodiment of the invention and of the opera tion thereof it will be evident that a precise con trol of the strength of the neutralizing ?eld can tralizing coil and a half-wave recti?er includ ing the anode and cathode of said tube, said ' circuit being coupled to said source only by means of said inductive relation to said demag» netizing coil; whereby changes‘ in the-magnitude of alternating current in said demagnetizing coil resulting from variations invthe magnetic effect of said body on said demagnetizing. coil when said body is in the ?eld thereof automatically producecorresponding changes in said unidirec» tional current in said neutralizing coil, a diode recti?er, a resistor connected in series with. said diode ‘recti?er across said source, connections ' from the cathode and'control gridpf said hatt 60 wave recti?er tube to said resistor whereby a be readily obtained over a large ‘range of ?eld ‘strength, and that the apparatus of the invention _may without any structural change whatever, be satisfactorily employed on power supply lines which diifer'considerably as to voltage or fre bias potential derived from said diode recti?er is impressed on said control grid, and variable, contact means on said resistor included in at least one of said connections for adjusting said potential, whereby the strength of said do quency or both. Furthermore, the apparatus is, 65 bias magnetizing ?eld may be accurately adiusted' over without change, adapted to the successful de a wide range. ' magnetization of bodies of a wide variety of types i 3. In apparatus for demagnetizing a magnetic and shapes and of any dimensions, so long as the body, the combination which includes a demag bodies, or required portions thereof, can be sym metrically disposed within the magnetic ?elds of _70 netizing coil connectible to a source of alternat ing current, said coilbeing disposable in induc coils 3 and 5. Rings, plates, billets and any other _' shapes and types of magnetizable bodies may thus What be is satisfactorilytreated. claimed is: , i tive relation to said body, va condenser connected . _. in series with said coil, said condenser having a j capacity such as at least approximately to res- - 1. In apparatus for demagnetizing'a'magnetic 75 onate said coil with the frequency of said source, I 2,409,424 7 - . v a bleeder resistor connected in shunt ‘to said condenser, a neutralizing coil inductively related to said demasnetizing coil and disposable in in ductive relation to said body, said coils being posi tioned to be in inductive relation simultaneously to the same portion of said body, a recti?er tube having an anode, a control grid and a cathode, and a recti?er circuit for producing unidirec 8 quency or said source, a bleeder resistor con nected in shunt to said condenser, a neutraliz ing coil inductively related to said demagnetiz ing coil and, being 0! the air-core type disposable in inductive relation to said body, said coils be ing positioned to be in inductive relation to the same portion or said body, a recti?er tube hav ing an anode, a control grid and a cathode, a tional neutralizing current in said neutralizing recti?er circuit (or producing unidirectional neu coil, said circuit including said neutralizing coil 10' tralizing current in said neutralizing coil, said and a half-wave recti?er including the anode and circuit comprising in series connection said neu cathode of said tube, said circuit being coupled tralizing coil, va. polarity-reversing switch, and a to said source only by means of said inductive. hall-wave recti?er including the anode and cath~ relation to said demagnetizing coil, whereby ode‘oi said tube, said circuit being coupled to changes in the magnitude 0! alternating current 15 said source-only by, means of said inductive rela in said demagnetizing coil resulting from varia tion to said demagnetizing coil whereby changes tions in the magnetic e?ect of said body on said in magnitude of the alternating current in said demagnetizing coil when said body isin the ?eld demagnetizing coil automatically produce corre thereof automatically produce corresponding sponding changes in the magnitude of said uni changes in said unidirectional current in said 20 directional current in said neutralizing coil, a neutralizing coil, a second recti?er, a resistor, diode recti?er, a second resistor connected in connected in series with said second recti?er serieswith said diode recti?er across said source, across said source, connections from the oath coarse resistance-adjusting means and ?ne re ode and control grid of said hall-wave recti?er sistance-adjusting means in contact with said tube to said resistor, whereby a bias potential second resistor, a ?lter condenser connected in derived from the second recti?er is impressed parallel with said second resistor, and connec on said control grid, and means for accurately tions from said adjusting means to the control adjusting said bias potential. grid and cathode, respectively, of said hall-wave 4. In apparatus for demagnetizing a magnetic recti?er tube for impressing on said control grid been‘, the combination which includes a demag a closely adjustable biasing potential derived from netlzing coil connectible to a source 01' alternatsaid diode recti?er, whereby the polarity of said ing current, said coil being of the air-core type .demagnetizing ?eld may be selected and the disposable in inductive relation to said body, a strength or said demasnetizing ?eld may be ac condenser connected in series with said coil, said curately adjusted over a wide range. condenser having a capacity such as at least ap proximately to resonate said coil with the ire I THEODORE ZUSCHLAG.