US2789658A

US2789658A - Apparatus for collecting suspended particles

Info

Publication number: US2789658A
Application number: US517170A
Authority: US
Inventors: Harry A Wintermute
Original assignee: Research Corp
Current assignee: Research Corp
Priority date: 1955-06-22
Filing date: 1955-06-22
Publication date: 1957-04-23
Anticipated expiration: 1974-04-23

Description

April 23, 1957 H. A. WINTERMUTE 2,789,658

APPARATUS FOR COLLECTING SUSPENDED PARTICLES Filed June` 22, 1955 4 Sheets-Sheett 1l fir g Il 0 I "l'llll'l'l- I u m w n 4 l INVENTOR [l/VR HARRY A. vyiNTERMuTE ATTORNEY April 23, 1957 H. A. WINTERMUTE AFFRTUS FR` COLLECTING SUSPENDED PARTICLES 4 Sheets-Sheet 2 Filed June 22, 1955 Nmk OMM INVENT OR HARRY A. WINTERMUTE ATTQRNEY April 23, 1957 H. A. wjNTERMUTE 2,789,658

APPARATUS FOR COLLECTING SUSPENDED PRTICLES Filed June 22, 1955 4 sheets-snee: s

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April 23, 1957 H. A. WINTERMUTE 2,789,658

APPARATUS FOR COLLECTING SUSPENDED PARTICLES Filed June 22, 1955 4 Sheets-Sheet 4 Erg- Z.

, INVENTOR HARRY A. wmTERMuTs ATTORNEY APPARATUS EUR COLLECTING SUSPENDED 1 PARTICLES Harry A. Wintermute, Plainfield, N. Il., assignor to Research Corporation, New York, N. Y., a corporation ofNew York Application lune 22, 1955, Serial No. 517,170

4 Claims. (Cl. 18S-7) This invention relates to electrical precipitation apparatus and more particularly and specifically apparatus for combining magnetic and electrostatic fields for the collection of a suspended particulate material.

lt has been discovered in passing liuc gases and the like through electrostatic precipitators a portion of the particles suspended in the gas that possess magnetic properties, such as, for example, those particles containing magnetite, hematite, limonite, pentlandite and wolframite, tend to move out into the gas stream within the precipi ator more readily than other particles thereby reducing the effectiveness and etiiciency of the precipitator.

It has also been discovered that by magnetizing the collecting electrodes of an electrostatic precipitator, the electrodes will more effectively hold dust patricles having magnetic properties after they have been precipitated thus reducing the percentage of dust particles passing through the precipitator and thereby increasing the efflciency and effectiveness of the gas cleaning apparatus.

lt is therefore a principal object of this invention to provide apparatus for combining magnetic fields and electrostatic fields to effectively increase precipitator efficiency when handling gases having suspended therein dust particles of magnetic susceptibility.

Another object of this invention is to provide new and improved electrostatic precipitator construction which `includes magnetized collecting electrodes to provide a magnetic eld between electrode faces transversely of the path and perpendicular to the direction of gas flow in the precipitator.

A further object of this invention is the provision of new and improved electrostatic precipitation apparatus including electro-magnetized electrodes creating magnetic fields in the path of gas flow through the precipitator.

Still another object of the present invention is the provision of new and improved electrostatic precipitator apparatus including permanent magnetic structures associ ated with the collecting electrodes of the precipitator which create magnetic fields across the path of gas ow in the precipitator.

A still further object and advantage of this invention is the provision of new and improved electrostatic pre cipitation apparatus for establishing magnetic fields between the collecting electrodes and across the path of gas ow within the precipitator which is readily adapted to construction of precipitators wherein the charging and precipitation of dust particles is simultaneous, as well as to precipitator constructions in which the particles are precharged before entering the collector section of the precipitator.

Still further objects and advantages of the present invention will become readily apparent to those skilled in the art when the accompanying drawings are read in the light of the following general statement and description.

The nature of the presen! invention may be stated in general terms as consisting of a new and improved particle collecting apparatus including a shell. a gas inlet, a gas outlet, spaced collecting and discharge electrodes suspended within the shell in the path of gas ow between' the inlet and the outlet, and means associated with said collecting electrodes establishing a magnetic field between the surfaces of adjacent electrodes.

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

Fig. l is a vertical section through a precipitator em'd bodying one form of the construction constituting the present invention.

Fig. 2 is a horizontal section taken on line 2 2, Fig. l.

Fig. 3 is a vertical section taken on line 33, Fig. l.

Fig. 4 is a view similar to Fig. 2 showing a modified form of the invention.

Fig. 5 is a horizontal section illustrating a still further modification of the present invention.

Fig. 6 is a view similar to Fig. 5 showing a modification of the form of the invention illustrated in Fig. 5.

Figs. 7 is a fragmentary, pictorial View of a modified electrode construction embodying the principles of the present invention.

In Figs. l-3 of the drawings there is illustrated a twopass electrostatic precipitator in which the charging and collecting of dust particles takes place in the same zone. The numeral 10 designates the precipitator shell which is provided at one end thereof with a gas inlet 12 and at the otherend with a gas outlet 14. The shell 10 is divided longitudinally into two sections 16 and 18, each of which is` provided with a hopper bottom 20 for the collection and discharge of precipitated material.

Additionally, each of the shell sections 16 and 18 of the precipitator is provided, in the instant embodiment of the invention, with identical electrostatic precipitating apparatus, generally designated at 22, into which is incorporated the unique and useful magnetic collection apparatus which constitutes, in combination with the electrostatic apparatus, the primary concept of this invention.

Because of the similarity between the combined electrostatic-magnetic precipitator apparatus contained in each of the two pass sections 16 and 18 ofthe precipitator shell, only that apparatus supported in the second pass section, 18, will be described hereinafter in detail.

In section 18 of the two-pass precipitator shell 10 a typical high tension electrode supporting frame 24.is suspended from insulated mountings 26 on the shell to lie horizontally in the upper region of the section and from which are supported in the usual manner a plurality of spaced, parallel rows of discharge electrodes 28, the lower ends of which are secured in the lower region of the shell section in a lower aligning Vframe 30.

A plurality of collecting electrodes 32 of the tiat plate type and constructed of iron or other magnetic material are supported from a pair of suitable end frame members 34 to extend longitudinally of the shell section in parallel spaced relationship, each plate also extending in parallel spaced relationship between and equally spaced from adjacent rows of the discharge electrodes 2S suspended from the frame 24, as is best illustrated in Fig. 2. Associated with each of the collecting electrode plates 32 are battlesthese plate bafes may be constructed of non-magnetic orA magnetic material.

The structures described above provide an electrostatic ,I

precipitator wherein flue gases passing around the discharge electrodes and between adjacent, spaced collecting electrodes is subjected to an electrostatic field inducing Patented Apr. 23,195?

suspended particles in the gas to be precipitated on the` In addition to the foregoing, however, the adjacent ends of each of the adjacentcollecting electrodesfare interconnected at spaced intervals vertically ofthe heightof the ends of, said collecting plates by permanent magnets 38 which are of` substantially U-shapedcontiguration in plan view and which are secured laterally of the electrode plate series with like polesv in each adjacent' pair of magnets laterally of the apparatusV being disposed. in end to end opposition as illustrated.

By this foregoing application of permanent magnets-secured between the ends of the collecting electrodes of an electrostatic precipitator structure, a magnetic eld is established between the opposed surfaces of adjacent col'- lecting electrode plates 32 in the precipitator which magnetic ields extend transversely of the direction of gas iiow through the precipitator thereby inliuencing suspended particles in the gas. stream having magnetic susceptibility causing them to be held by magnetic attraction upon the plate surfaces of the collecting electrodes rather than moving into the gas stream and passing through the precipitator. i

Referring to Fig. 4 of the drawings there is shown a modification of the aforedescribed embodiment of the present invention wherein the permanent magnets employed between the ends of adjacent magnetizable collecting electrode plates are replaced by a magnetic yoke 40 which includes a pair of'arms 42, each arm of each pair extends across the ends of the collecting electrodes 32 and are interconnected by a yoke bar 44 around which is provided a coil 46 connected to a source S of alternating current with one side of the line connected to said source through a rectier 48 which is shunted by a resistance 50.

Each of the collecting electrode plates 32 in this electromagnetic structure is shorter than the span between the two parallel arms 42 of the magnetic yoke, and the plates 32 are alternately arranged transversely of the precipitator lwith one end anchored to one of the yoke arms 42 and with the second end secured to a non-magnetic insert 51 which in turn is supported by the yoke arm 42 opposite that to which the plate end is secured. By this arrangement the opposite ends of adjacent collecting plates are secured to opposed arms 42 of the electro-magnetic yoke whereby north and south polarity is established between adjacent plates to create a magnetic eld between the opposed surfaces of the adjacent plates in the pref5() cipitator construction.

In this construction magnetic fields are established between the opposed surfaces of adjacent collecting electrodes in much the same manner as heretofore described relative to the permanent magnetic arrangement with the shunt resistance in the coil source supplying a small amount of reserved tlow magnetism to the fields for the purpose of counteracting residual, and/ or to aid in the residual magnetic action on the dust particles in the gas flow.

ln utilizing the electro-magnetic apparatus described above it has been found necessary in precipitators having shells formedy of magnetic material to break the continuity of the shell into separated sections as at 52 interposing in the broken sections closures of non-magnetic material 54 in the region of the precipitation apparatus. Likewise, non-magnetic inserts 56 must necessarily be made in the shell at those points where the magnetic yoke arms 42 extend through the shell wall to bridge the ends of the collecting electrodes.

Referring now to Fig. 5 of the drawings there is illustratcd a horizontal section through a fragment` of a typical electrostatic precipitator construction in which there are separate charging and collection sections within the precipitator and through which the gas flows in the order stated from the gas inlet ofthe precipitator to the outlet.

In this construction there is located within the precipitator shell 58 a plurality of parallel spaced collecting electrode plates 60 which are maintained at ground potential together with a plurality of parallel spaced collecting electrode plates 62 which lie alternately in equidistant intervals between and parallel with collecting plates 60. Plates 62 are insulated and maintained at a potential above that of plates 6); As in the previously disclosed form of the invention, all of the plates extend longitudinally of the shell and the plates 60 are of a greater length than,

they .plates 62 so that their ends terminate at a spaced distance beyond each end of the intermediate plate 62.

Located on the gas inlet side of the collecting plate structure above described are a plurality of tubular grounded electrodes 64 which extend vertically within the shell at equally spaced intervals transversely of the path of gas cw from the gas inlet to the collection plates. Located intermediate the grounded electrodes 64, and the collting plate structure are a plurality of ionizing electrodes 66, such as rods or wires. vertically within the shell at spaced intervals transversely of the shell and the gas ilow therein with the lateral spacing of the ionizing electrodes being the same as that ofj the groundedl electrodes 64 to provide a charging field 68 between each of the ionizing electrodes and the wo adjacent grounded electro-des 64. With this form of construction gas flowing from the inlet to the collection sect tion of the precipitator passes through charging lie1dsf68, ,f

established between the grounded and the ionizing electrodes inthe charging section whereby the dust particles suspended in the gas are ionized beforeV they enter the collecting section of the precipitator.

in' :this form of the invention, the adjacent ends of ad-g jacent collecting electrode plates 60 are interconnected by permanent magnets which are of the same construction Yand which are securedy in place'and located in the same manner as magnets 38 described relative .to the vform of the invention illustrated in Fig. 2. The perma-- nent magnets establish magnetic fields between the opposed surfaces of adjacent plates 6i) and the insulated plates 62 are magnetized with the surfaces thereof asi-l suming polarities opposite to the polarities of the surfaces of the plates 6l! which they oppose. In this construction, i

the collection plates, and the collection section of them precipitator whereby collected magnetizable mttrial is readily held to the plate surfaces.

.In Fig. 6 of the drawings there is illustrated a modified form of the invention as disclosed in Fig. 5 wherein an electro-magnetic construction is incorporated to replace the permanent magnets previously described. In this= modification non-magnetic inserts 72 are made in the precipitator shell 58 in the same manner las inserts 54 and 56 were made in the construction illustrated in Fig. 2, and an electro-magnetic construction including yoke arms 74, a yoke' coil '76, yoke bar 78, and non-magnetic insert sections 79 are substituted for the permanent magnets 7) in the same manner as the electro-magnetic structure illustrated in Fig. 4.

In Fig. 7 of the drawings there is illustrated a further modied construction of an electrostatic precipitation apparatus including means for establishing magnetic fields between the opposed surfaces of adjacent collecting electrodes. In this form of the invention a plurality of grounded collecting plates S2, of magnetic material, are arranged in conventional parallel spaced, relationship.

All oftheplates in the series constituting the collecting electrode assembly are interconnected by permanent, cylindrical magnets 8S which interconnect the opposed y surfaces ofLadjacent plates and which are supported in their interconnecting positions by non-magnetic rods or bolts 96a which, extend tlntnigh `aligned openings 92 in These rods are securedarsasa :arranged in any spaced pattern longitudinally and vertically of the plates as is necessary to establish magnetic fields between the opposed surfaces of the plates to the desired intensity.

By this foregoing construction magnetic flux distribution over the surfaces of the collectingelectrode plates within the precipitator apparatus is provided for the accomplishment of the same purposes and functions as has heretofore been set forth relative to the earlier described embodiments.

By the heretofore described constructions precipitator apparatus has been disclosed which includes magnetic fields provided between opposed surfaces of adjacent collecting plates within the apparatus which magnetic fields will have a limited tendency to supplement the electrostatic precipitation of magnetic susceptible particles suspended in a gaseous medium passed adjacent the plates, and which will have a decided function to produce a hold-ing force on these precipitated particles holding them to the collecting plates by magnetic attraction and thereby decreasing the portion of particles escaping through the precipitator with the gas stream.

It is, of course, understood that the magnetic holding force on the surfaces of the collecting electrode plates within the precipitator apparatus can be of varied tenacity dependent in part on the magnetic susceptibility of the particles suspended within the gas as well as upon the physical construction of the apparatus with regard to the strength of the magnets utilized, the number of magnets, the specific spacing and patern arrangement of magnets, the magnetic characteristics of the material constituting the collecting plates, the thickness of the plates, and the distance between adjacent collecting plates within the apparatus.

Accordingly, it is seen that apparatus has been dis closed which efficiently and effectively establishes a magnetic field across the path of gas flow through an electrostatic precipitator and which for the purpose of accomplishing the objects and advantages heretofore set forth and for the purpose of enabling practice of a new and improved method of precipitation which includes the steps of passing a flow of gas through an electrostatic field, over the surfaces of charged collecting electrode plates, and through magnetic fields extending perpendicular to the path of gas flow, discharging the gas, and collecting dust particles precipitated in the electrostatic field on collecting electrode plates, and holding said particles on the collecting plates by magnetic attraction.

Thus 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 having a gas inlet and a gas outlet spaced from the gas inlet, a plurality of parallel extended surface collecting plate electrodes positioned in said casing with the extended surfaces thereof positioned parallel to the flow of gas from the inlet to the outlet, a plurality of high voltage electrodes interspaced between the parallel collecting plate electrodes, means establishing electrostatic fields between the high voltage electrodes and the collecting plate electrodes and means establishing magnetic elds between the opposed surfaces of the collecting electrodes, whereby materials suspended in a gas stream are simultaneously subjected to both electrostatic and magnetic fields existing at right angles to the direction of the gas flow through the casing.

2. Precipitation apparatus as defined in claim 1 wherein permanent magnets are secured between the adjacent ends of adjacent collecting electrode plates at spaced intervals along the length of the ends of said plates; whereby magnetic fields are established between the opposed surfaces of adjacent collecting electrode plates which magnetic fields extend transversely of the path of gas flow through the precipitator and between the plates.

3. Precipitation apparatus as defined in claim 1 wherein electro-magnetic means interconnect the ends of adjacent collection electrode plates at spaced intervals along the lengths of the ends of said plates; whereby magnetic fields are established between the opposed surfaces of adjacent collecting electrode plates which magnetic fields extend transversely of the path of gas ow through the precipitator and between the plates.

4. Precipitation apparatus as defined in claim 1 including magnetic means interconnecting the ends of adjacent collecting electrode plates at spaced intervals along the lengths thereof, whereby magnetic fields are established between the opposed surfaces of adjacent collecting electrode plates.

References Cited in the le of this patent UNITED STATES PATENTS 977,570 Sutton et al. Dec. 6, 1910 1,949,660 Roberts Mar. 6, 1934 FOREIGN PATENTS 67,421 Sweden Oct. 25, 1927 683,488 France Mar. 3, 1930