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Publication numberUS2920987 A
Publication typeGrant
Publication dateJan 12, 1960
Filing dateJan 24, 1958
Priority dateJan 24, 1958
Publication numberUS 2920987 A, US 2920987A, US-A-2920987, US2920987 A, US2920987A
InventorsLionel Landry J, Sandholdt Frederick G
Original AssigneeNorton Co
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Electrostatic device
US 2920987 A
Abstract  available in
Previous page
Next page
Claims  available in
Description  (OCR text may contain errors)

SECTION A TO E XHAUST Jan. 12, 1960 J. L. LANDRY ETAL 2,920,987

ELECTROSTATIC DEVICE Filed Jan. 24, 1958 2 Q N U (\l m S m TO A-C- HIGH VOLTAGE SUPPLY FIG INVENTORY J-LlONEL LANDRY BY FREDERICK G. SANDHOLT gym m ATTORNEY brought into contact with a grounded conductor.

United States Patent ELECTROSTATIC DEVICE J. Lionel Landry, Waterford, and Frederick G. Sandholdt, North Troy, N.Y., assignors to Norton Company, Troy, N.Y., a corporation of Massachusetts Application January 24, 1958, Serial No. 711,025

1 Claim. (Cl. 134-1) The present invention relates generally to a device and method for removing particles from the surface of a workpiece and more particularly to an improved electrostatic cleaner and/ or static eliminator, especially adapted to remove statically charged particles from the surface of a poorly conductive material.

Any material which is either a non-conductor or a poor conductor of electrical charges presents a serious problem of static electricity removal after passing through rolls or in frictional contact with other surfaces. The frictional passage generates on the surface of the non-conductor a charge of static electricity which, due to the nature of the non-conductor, is not dissipated but builds up and is discharged only when the material is handled or otherwise This problem is particularly acute when the non-conductive material is passed through a series of rolls in frictional contact therewith as may happen in a variety of processing operations. The static charge is frequently so high as to constitute an explosion hazard due to the magnitude of the spark which occurs when the charge is discharged. 7

One of the most common situations in which the above problem arises is in the abrasive grinding or polishing of nonconductive material, as for example, rubber, vinyl tile, leather, paper, etc. The frictional contact of the abrasive belt or wheel plus the frictional contact of the various feeding and pressure rollers builds up a high static charge on the surface of the material being ground.

'An added problem which is present in such a grinding or polishing operation is that the small particles which have been ground olf, as well as any loose abrasive particles, tend to adhere to the surface of the material, bound there by the static charge so tightly that conventional brushes or cleaning means will not remove them.

The present invention has for its object the provision of a means for overcoming the disadvantages listed above.

A principal object of the invention is to provide a means for eliminating a static charge from the surface of poorly conductive material.

A further object is to provide a means for cleaning adherent particles from the surface of a workpiece.

An additional object is the provision of a method for cleaning surfaces and eliminating any static charge present thereon.

Another object is to provide a means for removing adherent particles from the surface of a statically charged, poorly conductive workpiece.

Other objects, if not specifically set forth herein, will be readily apparent from the following detailed description of the invention.

In the drawings:

Figure 1 is a schematic plan drawing showing the present invention employed in a conventional grinding operation.

Figure 2 is an end view of section A of Figure 1.

Referring now to Figure 1, section B illustrates a conventional grinding operation wherein a sheet of poorly ice conductive material 10 is fed through feed rolls 11 to a grinding cylinder 12. Pressure roll 13 maintains a close frictional contact between the sheet 10 and the abrasive surface 12' of cylinder 12. Additional guide rolls 14 and 14' are arranged to conduct the sheet 10 from the grinding operation into the area designated as section A which illustrates the present invention. After passing through the grinding operation, numerous small particles of the abraded material and abrasive grit remain bonded to the surface of the sheet 10 as illustrated at 15. These particles are tightly adhered to sheet 10 because of the static charge built up thereon due to passage through the grinding and feed rolls. The illustrated modification of. the present invention, designed to both relieve the dangerous static charge and to remove the adhered particles from the sheet comprises a suction head 16 having the end adjacent the sheet 10 open and a pipe 17 leading from the other end to a conventional exhaust fan (not shown). Mounted within the suction head and in contact with or closely adjacent to the sheet 10 is a rotating cylinder 18, preferably having a plurality of small raised projections 19 thereon. As shown, these projections 19 are formed by a wrapping of fancy wire cloth around the steel cylinder. Obviously, the cylinder could be formed with a plurality of projections itself,-or other types of wrappings having projecting wires or fins could be used. Cylinder 18 is grounded as illustrated by a wire 20. Immediately below the grounded cylinder is an electrode 21 of any suitable design, positioned as close as possible to the surface of the sheet 10 opposite the surface with which the projections 19 of cylinder 18 are in contact. Any suitable means may be utilized to obtain the positioning, but as illustrated, a table 22 having a slot 23 is adapted to receive the electrode 21 therein. Electrode 21 is connected as by wire 24 with a conventional source of high voltage alternating current. Suitable guide rolls 25 are provided beyond suction head 16 to guide sheet 10 out of the device.

In operation, the sheet 10, carrying a high charge of static electricity and a plurality of statically bound particles 15 on the upper surface thereof, passes into the electrostatic field set up between electrode 21 and the grounded cylinder 18. This field, due to the alternating current high voltage source to which electrode 21 is con nected, rapidly and continuously reverses itself, damping out the static charge to practically zero. The multipoint contacts afforded by the projections 19 on cylinder 18 are very effective in this respect. Additionally, due both to the electrostatic efiect and to the physical contact of projections 19 with the surface of sheet 10, the particles 15 are freed from the surface of sheet 10. As these particles are projected upwardly from the sheet 10 due to the action of the alternating current electrostatic field, the suction induced in the head 16 by the action of the exhaust fan connected to the opposite end of head 16, picks up and carries away the loosened particles. Sheet 10, as it passes from the head 16, is essentially free from both any static charge and from any adhered particles.

The voltages used in establishing the electrostatic field may vary from several thousand volts up to about one hundred thousand volts. The optimum voltage, as is well known in the electrostatic art, will be dependent upon the material being passed between the electrodes, its thickness, dielectric properties, etc. Generally, voltages in the range of from about 20,000 to 50,000 volts are satisfactory.

Many modifications can be made in the apparatus within the scope of the present invention, both in the grounded cylinder construction as stated above and also in the arrangement of the components. For example, one or more electrodes may be positioned on the same side of the sheet as the grounded cylinder and either grounded or connected to a high voltage source. Also, for some purposes the cylinder might be replaced by flat electrodes with or without projections, or the mouth of the suction head itself might act as the electrode. Obviously, the device may be reversed and the bottom electrode grounded while the cylinder is connected to the high voltage alternating current source. Many other modifications and variations not specifically set forth herein will be readily apparent to one skilled in the art, and no limitation on the scope of the invention is intended by the modifications described herein other than as may appear in the appended claims.

The invention, while particularly adapted for use with non-conductive or poorly conductive sheet material, is also of value in connection with the processing of strips, rods, and the like. The invention combines both the functions of cleaning and static eliminating and is of value wherever a problem of this type exists. Obviously, the invention may be used to clean workpieces even where the problem of static charges does not exist or is very minimal.

We claim:

A method of eliminating static electrical charges from the surface of a workpiece and removing particles adhered to such surface by the electrical charge thereon which comprises: passing a workpiece having particles adhered to the surface thereof by a static electrical charge through a constantly reversing electrostatic field to damp out the static charge on the surface of said workpiece and to cause said particles to be attracted upwardly from said surface; and at the same time subjecting said surface to the action of a reduced pressure zone to cause said particles to be removed permanently from said surface.

References Cited in the file of this patent UNITED STATES PATENTS 2,357,809 Carlson Sept. 12, 1944 2,358,334 Knowlton Sept. 19, 1944 2,576,882 Koole Nov. 27, 1951 2,752,271 Walkup June 26, 1956 2,825,078 Bugler Mar. 4, 1956

Patent Citations
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US2357809 *Nov 16, 1940Sep 12, 1944Chester F CarlsonElectrophotographic apparatus
US2358334 *Jun 2, 1942Sep 19, 1944United Shoe Machinery CorpMachine for treating sheet material
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US2752271 *Oct 5, 1955Jun 26, 1956Haloid CoElectrostatic cleaning of xerographic plates
US2825078 *Apr 7, 1953Mar 4, 1958Western Electric CoElectrostatic apparatus for separating articles
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3074086 *Feb 4, 1959Jan 22, 1963Tribune CompanyApparatus for removing dust from paper webs
US3077625 *Feb 19, 1959Feb 19, 1963Lindau Eric SFilm cleaner
US3096532 *May 5, 1960Jul 9, 1963Stokes F J CorpTablet duster
US3117333 *Nov 22, 1961Jan 14, 1964Xerox CorpAperture card cleaner
US3239863 *Aug 19, 1963Mar 15, 1966Thomas A GardnerPressure gradient web cleaning apparatus
US3302560 *Jun 11, 1965Feb 7, 1967Mousanto CompanySemi-automatic electrostatic printing system having moving screen
US3404418 *Feb 27, 1967Oct 8, 1968Xerox CorpSheet transport apparatus
US3436265 *Jan 8, 1965Apr 1, 1969Thomas A GardnerPressure gradient web cleaning method
US3536528 *Aug 16, 1968Oct 27, 1970Agfa Gevaert NvElectrostatic cleaner and method
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US3659526 *Dec 8, 1969May 2, 1972IttMagnetic and vacuum cleaning device for printer
US3801869 *Sep 25, 1972Apr 2, 1974S MasudaBooth for electrostatic powder painting with contact type electric field curtain
US3816157 *Aug 2, 1971Jun 11, 1974Xerox CorpToner reclaiming method
US3915737 *Nov 21, 1973Oct 28, 1975Gen Tire & Rubber CoMethod and apparatus for removing foreign particles from a calendered sheet by neutralization of static on the sheet
US4281431 *Jul 3, 1979Aug 4, 1981Saint-Gobain IndustriesSheet cleaning
US4378610 *Feb 24, 1981Apr 5, 1983Agfa-Gevaert AktiengesellschaftDevice for removing impurities from data carriers
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US5421901 *Sep 9, 1994Jun 6, 1995Eastman Kodak CompanyMethod and apparatus for cleaning a web
US6511581 *Sep 23, 1998Jan 28, 2003Valmet CorporationMethod for controlling mist and dust in the manufacture and finishing of paper and board by an ion blast wind
US6558456Feb 11, 2002May 6, 2003Valmet CorporationApparatus for controlling mist and dust in the manufacture and finishing of paper and board
US6680086Jul 7, 1999Jan 20, 2004Mesto Paper OyMethod for making paper, assembly for implementing the method and paper product produced by the method
US6787196Oct 29, 2003Sep 7, 2004Metso Paper OyApparatus for making a web of paper or board containing calcium carbonate
US6949013 *Aug 21, 2003Sep 27, 2005Jatco LtdPeripheral length correction device of metal rings
US7198841Nov 4, 2003Apr 3, 2007Metso Paper OyPaper having a cellulosic fiber layer treated with elementary particles
US8727832 *Sep 27, 2011May 20, 2014HGST Netherlands B.V.System, method and apparatus for enhanced cleaning and polishing of magnetic recording disk
US20040074620 *Oct 8, 2003Apr 22, 2004Valmet CorporationMethod for treating a paper or board web with a treatment material
US20040079503 *Oct 16, 2003Apr 29, 2004Valmet CorporationUse of recycled calcium carbonate in the treatment of a paper, board or nonwoven product
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U.S. Classification134/1, 15/1.51, 15/77
International ClassificationA47L9/04, A47L13/40, H05F3/02, A47L13/10
Cooperative ClassificationA47L9/04, A47L13/40, H05F3/02
European ClassificationH05F3/02, A47L9/04, A47L13/40