US2904178A - Apparatus for collecting magnetic susceptible material - Google Patents

Description

p 1959 H. A. WINTERMUTE 2,904,178

APPARATUS FOR COLLECTING MAGNETIC SUSCEPTIBLE MATERIAL Filed March 13, 19 56 3 Sheets-Sheet l INVENTOR HARRY A. WINTERMUTE BY AQVW M' ATTORNEY Sept. 15, 959 H. A. WINTERMUTE 2,904,178

APPARATUS FOR COLLECTING MAGNETIC SUSCEPTIBLE MATERIAL Filed March 15, 1956 z Sheets-Sheet 2 will WIW IM 72 NTOR TO A WINTERMUTE ATTO EY Sept. 1959 H. A. WINTERMUTE 2,904,178

APPARATUS FOR COLLECTING MAGNETIC SUSCEPTIBLE MATERIAL INVENTOR HARRY A. WINTERMUTE BY ALM/T'M ATTORNEY APPARATUS FOR COLLECTING MAGNETIC SUSCEPTIBLE MATERIAL Harry A. Wintermute, Plainfield, N.J., assignor to Research Corporation, New York, N.Y., a corporation of New York Application March 13, 1956, Serial No. 571,301

3 Claims. (Cl. 209-416) This invention relates to new and useful improvements in methods and apparatus for the precipitation and/or collection of materials having magnetic characteristics.

In prior conventional magnetic apparatus utilized for the precipitation and collection of materials of magnetic susceptibility it has been discovered that such materials often tend to collect and build up in the magnetic treating areas of such apparatus thereby interfering with continued collection and greatly reducing the efficiency of the apparatus.

Certain attempts have been made in prior apparatus for the wet separation and collection of magnetic materials to reduce the undesirable factor of build-up in the collection area by use of wash liquids directed over such areas. However, this method of cleaning the treating zone is costly, incapable of efficient control, and results in further dilution of collected particles thereby requiring additional apparatus for separating the wash liquid from the separated materials.

It is therefore a general object of the present invention to provide greatly improved methods and apparatus for the collection and separation of magnetic materials by magnetic forces.

Another object of this invention is the provision of new and improved methods and apparatus for the separation and collection of magnetic materials which is readily capable of adaptation to both wet and dry separation procedures.

Still another object of this invention is the provision of apparatus for the separation and collection of magnetic materials which utilizes a treating zone taking the form of a flux gap within a magnetic circuit wherein the flux in said gap is alternately shifted into and out of the gap permitting collected particles retained by magnetic attraction within the treating zone to move with the material stream through said zone during those periods when said flux is shifted away from the treating zone gap.

A still further object lies in the provision of magnetic separation apparatus as described which includes a magnetic circuit having a flux gap taking the form of a treating zone through which materials to be separated and collected are passed together with a second magnetic circuit having an adjustable flux gap therein with means for alternately increasing and decreasing the size of said gap in said secondary circuit thereby alternately shifting the magnetic flux from the treating zone to the flux gap in the secondary circuit for reasons hereto-fore assigned.

Still another object and advantage of this invention lies in the provision of magnetic separation apparatus of the type described which is extremely simple and inexpensive in design and manufacture yet durable and long lasting in use with a minimum requirement of repair and upkeep.

Still further objects and advantages of this invention will become more readily evident to those skilled in the art when the following general statement and description are read in the light of the, accompanying drawings,

atent The nature of the present invention may be stated generally as relating to magnetic separation apparatus which includes a magnetic circuit having an open flux gap wherein said flux gap serves as a treating zone for the passage of materials to be separated thereabout, a second magnetic circuit parallel to said first circuit, a flux gap in said second parallel circuit remote to said treating zone, and means for alternately increasing and decreasing said second flux gap whereby the magnetic flux will be alternately shifted from the treating zone to the flux gap of the secondary parallel circuit permitting movement of magnetic materials collected in the treating zone through said gap to a point of collection.

Referring now to the accompanying drawings in which like numerals designate similar parts throughout the several views:

Fig. 1 is a vertical, sectional schematic view of wet separating apparatus embodying the present invention.

Fig. 2 is a fragmentary vertical schematic view illustrating a second form of wet separating apparatus embodying the present invention.

Fig. 3 is a vertical sectional view of an electrical gas precipitator embodying the present invention.

Fig. 4 is a horizontal sectional view of the apparatus disclosed in Fig. 3.

Fig. 5 is a horizontal section view similar to Fig. 4 of a modified form of an electrical precipitator embodying the present invention.

Referring now to Fig. l of the drawings there is disclosed a form of wet separation apparatus which includes spaced polesdtl each of which is energized by its respective windings 12 and each being provided with a rotating pole piece 14, said pole pieces being located in spaced relationship to one another. The poles 10, and their revolving pole pieces 14, form together with Windings 12 and circuit closing yokes 18 a magnetic circuit having a concentrated magnetic field between the opposed spaced revolving pole pieces 14 with the maximum magnetic field extending between horizontally'opposed peripheral edge portions of the spaced poles, said field diminishing between corresponding peripheral portions in vertical directions away from their positions of horizontal opposition.

A vertical tube or box 20 of non-magnetic material extends between the opposed faces of the revolving pole pieces 14, the box or tube having arcuate inset detents 22 in which each of the pole pieces rotate thereby providing a reduced vertical passage in said tube intermediate said detents 22. The tube is provided below the arcuate detents 22 with a pair of spaced baflies 24 which extend vertically within the tube immediately below the detents 22 and which divide the lower portion of the tube into a central passage 26 and two opposed side passages 28. The central passage 26 connects vertically with a collection point (not shown) for the non-magnetic material separated by the apparatus. The opposed side passages 28 connect at their lower ends with collecting tanks (not shown) for the magnetic material to be separated by the apparatus.

A slurry containing the magnetic materials to be separated is introduced through an inlet 32 into the upper' end of the tube 20 to flow downwardly, as indicated by arrows 34, through the reduced central passage in the 7 tube intermediate the arcuate detents 22 wherein it is subjected to the magnetic field established between the,

they fall by gravity as the magnetic field between the corresponding peripheral portions of the pole pieces diminishes with their downward rotation away from positions of horizontal opposition, and such magnetic materials are subsequently collected below said side passages 28. At the same time-non-magnetic materials tend to fall by gravity from within the central region of'the' reduced area of the treating zone into the central passage between side passages 28 from which they are discharged to their remote collection point.

In addition to the foregoing apparatus, the poles 10 are provided with magnetic by-pass extensions 36 which extend vertically above the top of the tube 20 and which are provided with horizontal extensions 38 disposed in end to end opposition and which horizontal extensions are provided with a flux gap 40 intermediate their opposed adjacent faces. Located within the flux gap 40 is a rotating member 42 of magnetic material which is operatively connected to a motor 44 or the like which selectively rotates said rotating member at a predetermined speed or at selected intervals. The rotating member 42 is of a configuration providing a greater dimension in one direction than at right angles to said direction whereby rotation of the pole piece will provide an alternately increasing and decreasing flux gap between the opposed ends of the horizontal extensions 38. By preselection the minimum fiux gap obtained between the extensions may be less than the flux gap between the rotating pole pieces 14 while the maximum flux gap, obtained by rotation of the member 42, is greater than the gap intermediate the rotating pole members 14.

In operation of the separation apparatus described there is a normal tendency for the magnetic materials contained in wet slurry to collect and adhere to the arcuate inner walls of the arcuate detents 22 under the magnetic influence of the rotating pole pieces 14. However, rotation of the rotating member 42 will alternately increase and decrease the flux gap intermediate the extension members 38 thereby shifting the flux from the magnetic circuit established between the pole members 10 through the by-pass extensions 36 and across the flux gap in the parallel magnetic circuit between the opposed ends of the extensions 38. This operation of alternately shifting the flux from one magnetic circuit to the other will cause periodic movement of magetic materials attracted to the walls of detents 22 through the treating zone of the separator during those intervals when the magnetic field between the rotating pole pieces is broken by the shifting of the flux to the flux gap of the secondary parallel circuit.

In Fig. 2 of the drawings there is illustrated a second form of wet separator which conventionally utilizes a vertical plate 46 of non-magnetic material and a source of slurry 48 containing, the magnetic materials to be separated with means for directing said slurry in a vertical stream 50 spaced away from the plate 46. An electromagnet 52 is provided with spaced pole arms 53 having the pole tip portions 54 thereof angularly inclined toward each other and terminating in a spaced relationship which is less than the distance between the main portions of the spaced pole arms 53. The electromagnet 52 is positioned so as to locate its pole tips 54 in closely spaced adjacency to that face of the collecting plate 46 opposed to the falling slurry stream 50. Thus energization of the solenoids 55 of the magnetic poles 53 produces a magnetic field between the pole tips 54 penetrating the plate 46 and causing an attraction of the magnetic materials in the slurry stream 50 to the plate surfaces upon which they are collected.

The main pole arms 53 of the magnet 52 are provided with a bridging arrangement which includes short pole extensions 56 extending in opposed relationship and a rotating member 58, driven from a motor or the like 60 intermediate the pole extensions 56. The rotating member 58, as rotating member 42 above described, is of such a shape and configuration so that the flux gap between the rotating memberand the pole extensions 56 is less than the flux gap-.- between the pole tips 54 when the member is aligned between the extensions 56 and greater than the gap between tips 54 when perpendicular to the extensions 56. Hence rotation of the member 58 will alternately bridge the magnetic circuit between the poles 54 shifting the flux flow in said magnetic circuit through said bridge and away from said pole tips whereupon the magnetic materials collected upon the plate will be permitted to fall by gravity into a collection member 62.

The principles of the present invention are also adaptable to dry precipitation of magnetic materials such as the electrostatic precipitation of dust particles or the like from flue gases. For example, theuse of magnetic fields between the collecting electrodes and across the path of gas flow in electrostatic precipitation apparatus has been utilized for the purpose of increasing the efficiency of collection of magnetically susceptible particles in flue gases and the like. The present invention greatlyimproves and increases the efliciency of prior devices of this general type.

In Figs. 3 and 4 of the drawings there is illustrated an electrostatic precipitator, of the type in which the charging and collecting of dust particles takes place in a single zone, which includes a precipitator shell 64 which is provided with a gas inlet 66 at one end and a gas outlet 68 at the second end. The shell is divided longitudinally into two sections each of which is provided with a hopper bottom 70 for the collection and discharge of precipitated material of magnetic susceptibility. Because of the similarity between the combined electrostatic-magnetic apparatus contained in each pass of the two pass section, only that apparatus supported in the second pass section 72 will be described hereinafter in detail.

In section 72 a typical high tension frame 74 is suspended from insulator mountings 76 and supports in turn in the usual manner a plurality of spaced discharge electrodes 78. A plurality of collecting electrodes 80 of the flat plate type are supported from a pair of suitable frame members 81 to extend longitudinally in spaced relationship one between each pair of spaced rows of discharge electrodes 80. Y

The abovedescribed construction provides an apparatus wherein flue gas passing around the discharge electrodes is subjected to an electrostatic field inducing suspended particles in the gas to be precipitated on the surfaces of the collecting electrodes 80 from which they fall into the collecting hopper 70.

Associated with the collecting electrodes 80 is a magnetic yoke 82 which includes a yoke bar 84 located externally of the shell and around which is provided an energizing coil 86 controlled from an external source 88 of alternating current, one side of said coil line being connected to a rectifier generally designated at 90. The magnetic yoke 82 further includes a pair of spaced arms 92 extending one from each end of the yoke in parallel relationship transversely through the housing 64 with the arms being insulated from the housing by inserts 94 of non-magnetic material in the housing wall. The extended ends of the arms 92 are provided with extensions 96 extending to terminate in end to end relationship in parallel with yoke bar 84 on the opposite side of the housing. A rotating member 98, similar to rotating members 42 and 58 heretofore described, is located intermediate the opposed adjacent ends of extensions 96 and is powered by a motor 100 or the like.

Within the precipitator shell 64 each of the collecting electrode plates 80 is shorter than the span intermediate the two parallel arms 92 of the eleetro-magnetic yoke, and the plates 80 are arranged transversely of the precipitator so that said plates alternately are provided with one end anchored to one of the yoke arms 92 and the second end secured to a non-magnetic bridge 102 which interconnects the plate with that yoke arm 92 oppositeto the arm to which the opposite plate end is secured. Thus the opposite ends of adjacent plates transversely of the housing are secured to opposite yoke arms 92 whereby north and south polarity is established between adjacent plates creating a magnetic field between the opposed surfaces of adjacent plates in the precipitator construction.

In accordance with known practice the foregoing precipitator arrangement serves to supplement the electrostatic fields within the precipitator with magnetic fields between opposed surfaces of adjacent plates thereby tending to hold magnetically susceptible particles on the collecting plate surfaces and preventing them from passing with the gas stream through the outlet of the precipitator. At the same time, however, rotation of the member 98 will serve to interrupt the magnetic fields formed between opposed plate surfaces by alternately providing a greater or lesser flux gap between the adjacent ends of extensions 96 than the fixed flux gap between adjacent plates. In this manner, magnetic materials built up on the plate surfaces are alternately freed from the magnetic forces of the flux field between the plates and permitted to fall by gravity in the direction of the collecting hopper 70 thereby preventing undesirable accumulation of particles on the plate surfaces over extended periods.

In the form of the invention disclosed in Fig. 5 there is shown a precipitator similar to that described relative to Fig. 4 with two principal exceptions. One, the precipitator disclosed in Fig. 5 is of a type wherein the gas entering the precipitator through the inlet 104 is subjected to a charging field 106 established between spaced grounded electrodes 108 and ionizing electrodes 110 located in spaced relationship to the grounded electrodes 108. Thus the gas upon entering the pass of the precipitator has been subjected to a charging field which ionizes the magnetically susceptible dust particles suspended therein.

The second exception lies in the substitution in the precipitator disclosed in Fig. 5 of insulated plates 112 for the discharge electrodes 78 of the precipitator disclosed in Fig. 4. The insulated plates are located in parallel spaced relationship one intermediate each pair of adjacent collecting electrodes 80 so that magnetic fields are established between the opposed surfaces of adjacent collecting electrodes 80 and the insulated plates 112 with the surfaces of adjacent plates assuming opposite polarities.

The remaining structure of the precipitator shown in Fig. 5 is identical with that shown and described in Fig. 4 with identical operation in that rotation of the interrupter member 98 will alternately shift the flux field from between the opposed surfaces of adjacent plates to the gap intermediate adjacent ends of extensions 96 for the same purpose as has been heretofore described.

Accordingly it is scen that apparatus has been disclosed which efficiently and effectively provides for the establishment of a magnetic field across the path of a gas or slurry flow for the purpose of attracting and separating magnetically susceptible materials from said flow to be collected upon a plate surface, wherein new and improved methods and apparatus are provided which permit the shifting of the magnetic flux gap in a secondary parallel circuit whereupon the magnetic attraction is alternately diminished upon the collected material to permit them to pass through the apparatus for collection.

It is also fully contemplated and anticipated that the principles of the present invention could be practiced and the aforedescribed new and useful results obtained by the substitution of permanent magnets for the electromagnets hereinbefore described. For example, in Fig. 2 of the drawing, the electromagnet 52 and energizing solenoids 55 could be replaced with a horseshoe-shaped permanent magnet.

It is also seen that the methods and apparatus herein disclosed accomplish all of the objects and advantages heretofore set forth and enable the practice of a new and improved method of magnetic separation of magnetically susceptible materials from gas and liquid currents for greater efiiciency in both dry and wet separation processes.

Th-us having described and explained the construction and operation of the present invention and the new and useful results obtained by the practice thereof what is desired to be claimed is:

1. Magnetic separation means for separating magnetically susceptible materials from a stream of mixed materials including a magnet having spaced poles establishing a field of magnetic flux between said poles, means for directing a stream of mixed materials to be separated between said spaced poles, and means for alternately shifting said flux to and away from said poles wherein said means for alternately shifting said flux includes a parallel magnetic circuit having a rotatable bridge member therein and motor means for rotating said bridge member to alternately shift the primary flux between the spaced poles and said parallel circuit.

2. Electromagnetic separation means for separating magnetically susceptible materials from a' stream of mixed materials including a pair of spaced poles defining a passage for a stream of mixed materials, solenoid means for energizing said poles and establishing a field therebetween, a second pair of spaced poles connected one to each of said first-named poles defining a second parallel field therebetween, an irregular shaped magnetic member rotatably mounted intermediate said second poles, and motor means for rotating said irregular shaped member to continuously shift the primary flux between said first and second spaced poles.

3. A construction as defined in claim 2 wherein plate members are disposed intermediate said first-named poles forming a passage for said stream of mixed materials therethrough, and said plate members forming collecting surfaces for magnetically susceptible materials.

References Cited in the file of this patent UNITED STATES PATENTS 462,321 Moffat et al. Nov. 3, 1891 1,371,825 Uhlig Mar. 15, 1921 2,088,364 Ellis July 27, 1937 2,460,921 Candy Feb. 8, 1949 FOREIGN PATENTS 3,046 Great Britain Feb. 5, 1913

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