US3320479A - Charged web collecting apparatus - Google Patents

Charged web collecting apparatus Download PDF

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Publication number
US3320479A
US3320479A US458358A US45835865A US3320479A US 3320479 A US3320479 A US 3320479A US 458358 A US458358 A US 458358A US 45835865 A US45835865 A US 45835865A US 3320479 A US3320479 A US 3320479A
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United States
Prior art keywords
plate
laydown
electrode
path
trailing edge
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 - Lifetime
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US458358A
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English (en)
Inventor
Owens John Edward
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.)
EIDP Inc
Original Assignee
EI Du Pont de Nemours and Co
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Filing date
Publication date
Application filed by EI Du Pont de Nemours and Co filed Critical EI Du Pont de Nemours and Co
Priority to US458358A priority Critical patent/US3320479A/en
Priority to NL6605750A priority patent/NL6605750A/xx
Application granted granted Critical
Publication of US3320479A publication Critical patent/US3320479A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05F—STATIC ELECTRICITY; NATURALLY-OCCURRING ELECTRICITY
    • H05F3/00—Carrying-off electrostatic charges
    • H05F3/04—Carrying-off electrostatic charges by means of spark gaps or other discharge devices
    • D—TEXTILES; PAPER
    • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
    • D01D—MECHANICAL METHODS OR APPARATUS IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS
    • D01D5/00—Formation of filaments, threads, or the like
    • D01D5/04—Dry spinning methods

Definitions

  • a collecting surface capable of continuous motion in a given direction and disposed to collect a continuous deposit of electrostatically charged fibrous elements on one face
  • the collecting surface passes through an electrostatic field generated by a laydown plate electrode disposed on that face of the collecting surface opposite to the face on which the elements are deposited.
  • the electrostatic field produced by charges on the plate electrode opposite in polarity to the depositing elements, causes the elements to be strongly attracted to the collecting surface.
  • the trailing edge of the laydown plate electrode be a knife edge or a series of sharp points, i.e. a sharply tapered shape.
  • the collecting surface receives the charged elements they are held to the surface as a non-woven sheet by electrostatic charge.
  • the charge on the elements is largely neutralized by ionization of adjacent vapors.
  • small residual charges are largely discharged due to the corona discharge resulting from the high potential at the sharply tapered edge. Failure to use a sharp, trailing edge upon the laydown plate results in disruptions and nonuniforrnities in the sheet product caused by electrostatic fibrous erections occurring after the formed sheet leaves the area of influence of the laydown plate.
  • an elongated anti-rollback electrode is added to the apparatus of the parent application aligned parallel to the trailing edge of the laydown plate electrode and situated on that side of the collecting surface upon which the fibrous elements are deposited, i.e. along the face of the collecting surface opposite to the face along which the laydown plate electrode is disposed.
  • the anti-rollback electrode is charged opposite to the charge on the laydown plate electrode.
  • a structure having an arcuate surface with a low radius of curvature, such as a wire is preferred for use as the anti-rollback electrode.
  • the high potential between the sharply tapered trailing edge of the plate electrode and the anti-rollback electrode with a low radius of curvature promotes formation of a corona discharge.
  • FIGURE 1 is a cross-sectional elevation indicating schematically the arrangement of the various elements in a system wherein the collecting system of the present invention is particularly useful.
  • FIGURE 2 is a perspective view of the laydown plate electrode.
  • FIGURE 3 is a much enlarged cross-section of the cylindrical anti-rollback electrode 50 of FIGURE 1.
  • FIGURES 4 to 7 show anti-rollback electrodes of various shapes.
  • a spinneret device 1 is connected to a source of polymer dissolved in an organic solvent.
  • Polymer solution 2 at a temperature above the solvent boiling point and under pressure is fed through extrusion orifice 3 into intermediate pressure or let-down pressure zone 4 and then through spinning orifice 5 into web forming chamber 6 which is at a much lower pressure and near atmospheric pressure.
  • the extrudate from spinning orifice 5 is a plexifilament 7.
  • baffle S is mounted on shaft 10 which in turn is oscillatably mounted in bearing 11 and is powered to oscillate by means not shown. While oscillation of the bafile is not essential, it is preferred in the preparation of wide sheets of plexifilamentary material.
  • Target plate 13 and ion gun 14 are disposed on opposite sides of the path of advance of the plexifilament web, downstream from the web forming and mechanical spreading devices.
  • Target plate 13 is so disposed that the vapor blast originating at 5 and the air flow pattern in chamber 6 holds plexifilament 7 in brushing contact with its charging surface.
  • Target plate 13 is connected to ground through wire 15 and microammeter 16, the latter indicating target plate current.
  • the position of needles 25 with reference to target plate 13 is important for efiicient operation. It will be apparent that the clearance between the needle points and plate 13 should be :as small as efi'icient operation will permit. Generally a clearance of from about 1 to about 2 inches is satisfactory although this will vary with the design and capacity of the particular equipment.
  • Plexifilament 7 passes through the charging zone, provided by high voltage negative D.C. source 35 operating through ion gun 14 and target plate 13, and is thereby provided with a negative charge.
  • the charged pleXifilament is deposited upon a collecting surface 9.
  • the surface illustrated is a continuous belt forwarded by drive rolls 36.
  • the belt passes through an electrostatic field emanating from charged laydown plate 45 which receives its charge, opposite in polarity to that imposed on plexifilament 7, from high voltage direct current source 37. It will be understood, of course, that the direct current may have an oscillating component provided that the resultant polarity is not reversed during operation. Due to the electrostatic forces, the plexifilament 7 is attracted to laydown plate electrode 45 and clings therefore to collecting surface 9 in its arranged condition as a sheet 38 with sufficient force to overcome the disruptive influence of whatever vapor blast may reach this area.
  • Electrode 50 is connected to a source of direct current 51 opposite in polarity to the power supply of laydown plate electrode 45. The in creased ion density between the sharp trailing edge 47 and the anti-rollback electrode 50 promotes much more rapid neutralization of the charges on the sheet 38 as the sheet passes over the trailing edge.
  • the sheet 38 is lightly compacted by compaction roll 44 and is withdrawn from enclosure 6 through port 39 by means of wind-up roll 42.
  • Flexible elements 40 may be provided to assist in retaining vapors within chamber 6.
  • a conventional solvent recovery unit 43 may be beneficially employed to improve economic operation.
  • Plate 45 is shown in detail in a perspective view in FIGURE 2.
  • the laydown plate electrode 45 is in essence a flat conducting plate with one broad flat surface disposed parallel and adjacent to collecting surface 9, i.e., conforming to the shape of the collecting surface.
  • the leading edge 46 and side edges 49 of plate 45 are rounded.
  • a sharply tapered shape, i.e. knife-edge 47 is provided along the trailing end of plate 45 and a terminal for hook-up to power source 37 is provided at 48.
  • plexifilament 7 is deposited near the leading edge of plate 45.
  • Sheet 38 is formed on laydown o-f plexifilament 7 upon collecting surface 9.
  • the improved apparatus of this invention has particular value when film-fibril material is flash-spun into a chamber containing principally a solvent gas such as Freon-11 and very little air. Accordingly, it has been found that the fibers can be controlled in a closed spinning chamber by providing an antirollback electrode disposed parallel to and near the trailing edge of the laydown plate electrode.
  • the length of the electrode 50 is approximately equal to the width of laydown plate electrode 45, both items having the approximate width of sheet 38 carried on belt 9.
  • electrode 50 is cylindrical as shown in FIG- URE 3 and consists of a single wire of 10 to mils diameter (0.010 to 0.100 in.), but preferably is 15 to 30 mils in diameter. The wire may also be multistrand.
  • Another alternative is a sharp-edged bar having a knife edge as shown in FIGURES 4 and 5 with radius of ourvature less than about 50 mils (0.051 in.).
  • this type of electrode requires special care of operation and construction in that the large mass of metal tends to attract webs.
  • anti-rollback electrode is a conducting bar having a series of conducting points extending in parallel from the bar along its entire length as shown in cross-section in FIGURE 6.
  • a suitable electrode of this type has points with three mil radius at the tip.
  • FIGURE 7 is a front view of another variation of the anti-rollback electrode consisting of a wire screen having a solid metal shield 61 welded around three of its edges.
  • the shield is made of bar stock or tubing having a large diameter to avoid unwanted corona discharge.
  • the points 60 promote the corona discharge along the entire length of the electrode.
  • the anti-rollback electrode is located about 1 to 6 inches above the collecting surface. It may be placed directly over the trailing edge of the plate electrode or may be located as much as about 6 inches downstream. It should not, however, be so close to the wall of web forming chamber 6 (FIGURE 1) or to compaction roll 44 as to cause appreciable corona discharge to the chamber wall or to the roll.
  • Apparatus for attracting, collecting and discharging a sheet of electrostatically charged fibrous elements comprising in combination a continuous surface adapted to move continuously in a given direction and providing on one face, a path of laydown for the said fibrous elements, a charged plate conforming to the shape of the said continuous surface disposed along and extending transversely of the face of the said surface opposite to that providing the said path of laydown and adapted to generate an electrostatic field of opposite polarity in the path of the said continuous surface, the said plate having a broad side disposed toward said surface, the said plate extending substantially completely across the width of the said path of laydown and terminating at its trailing edge in a sharply tapered shape adapted to provide a corona discharge between the said sheet and the said plate, a charged elongated electrode positioned above and extending substantially across the width of the said path of laydown, proximate to the said trailing edge of the said plate, said electrode having an arcuate surface of low radius of curvature disposed toward said trailing edge and

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Textile Engineering (AREA)
  • Elimination Of Static Electricity (AREA)
US458358A 1965-05-24 1965-05-24 Charged web collecting apparatus Expired - Lifetime US3320479A (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
US458358A US3320479A (en) 1965-05-24 1965-05-24 Charged web collecting apparatus
NL6605750A NL6605750A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html) 1965-05-24 1966-04-28

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US458358A US3320479A (en) 1965-05-24 1965-05-24 Charged web collecting apparatus
NL6605750A NL6605750A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html) 1965-05-24 1966-04-28

Publications (1)

Publication Number Publication Date
US3320479A true US3320479A (en) 1967-05-16

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Application Number Title Priority Date Filing Date
US458358A Expired - Lifetime US3320479A (en) 1965-05-24 1965-05-24 Charged web collecting apparatus

Country Status (2)

Country Link
US (1) US3320479A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
NL (1) NL6605750A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3453428A (en) * 1966-02-02 1969-07-01 Du Pont Corona discharge device having a renewable target electrode
US3475652A (en) * 1966-12-05 1969-10-28 Simco Co Inc The Dual phase static eliminator
US3489895A (en) * 1966-02-02 1970-01-13 Du Pont Regulated electrostatic charging apparatus
US3991479A (en) * 1975-11-07 1976-11-16 Michael Dionne Clothes dryer with anti-static magnet
US4989995A (en) * 1988-09-07 1991-02-05 Fabritec International Corporation Anti-static garment bag for reducing static buildup in the drycleaning process
US5082466A (en) * 1988-09-07 1992-01-21 Fabritec International Corporation Anti-static garment bag for reducing static buildup in the drycleaning process
US5558830A (en) * 1994-12-02 1996-09-24 E. I. Du Pont De Nemours And Company Wand purging for electrostatic charging system in flash spinning process
CN102770589A (zh) * 2010-09-29 2012-11-07 松下电器产业株式会社 纳米纤维制造系统及纳米纤维制造方法
RU2668446C1 (ru) * 2018-01-16 2018-10-01 Акционерное общество "Научно-исследовательский институт синтетического волокна с экспериментальным заводом" (АО "ВНИИСВ") Установка для получения сорбционно-фильтрующих нетканых материалов с улучшенными свойствами из растворов полимеров методом аэродинамического формования
US11384452B2 (en) * 2017-10-19 2022-07-12 Innovative Mechanical Engineering Technologies B.V. Electrospinning device and method

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US844300A (en) * 1906-02-12 1907-02-12 Chapman Electric Neutralizer Company Process of neutralizing static electricity.
US2483542A (en) * 1945-10-24 1949-10-04 Goss Printing Press Co Ltd Static eliminator for printing presses
US3122634A (en) * 1962-04-04 1964-02-25 Xerox Corp Controlled charging in xerographic copying apparatus

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US844300A (en) * 1906-02-12 1907-02-12 Chapman Electric Neutralizer Company Process of neutralizing static electricity.
US2483542A (en) * 1945-10-24 1949-10-04 Goss Printing Press Co Ltd Static eliminator for printing presses
US3122634A (en) * 1962-04-04 1964-02-25 Xerox Corp Controlled charging in xerographic copying apparatus

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3453428A (en) * 1966-02-02 1969-07-01 Du Pont Corona discharge device having a renewable target electrode
US3489895A (en) * 1966-02-02 1970-01-13 Du Pont Regulated electrostatic charging apparatus
US3475652A (en) * 1966-12-05 1969-10-28 Simco Co Inc The Dual phase static eliminator
US3991479A (en) * 1975-11-07 1976-11-16 Michael Dionne Clothes dryer with anti-static magnet
US4989995A (en) * 1988-09-07 1991-02-05 Fabritec International Corporation Anti-static garment bag for reducing static buildup in the drycleaning process
US5082466A (en) * 1988-09-07 1992-01-21 Fabritec International Corporation Anti-static garment bag for reducing static buildup in the drycleaning process
US5558830A (en) * 1994-12-02 1996-09-24 E. I. Du Pont De Nemours And Company Wand purging for electrostatic charging system in flash spinning process
US5750152A (en) * 1994-12-02 1998-05-12 E. I. Du Pont De Nemours And Company Wand purging for electrostatic charging system in flash spinning apparatus
CN102770589A (zh) * 2010-09-29 2012-11-07 松下电器产业株式会社 纳米纤维制造系统及纳米纤维制造方法
CN102770589B (zh) * 2010-09-29 2016-03-16 松下知识产权经营株式会社 纳米纤维制造系统及纳米纤维制造方法
US11384452B2 (en) * 2017-10-19 2022-07-12 Innovative Mechanical Engineering Technologies B.V. Electrospinning device and method
RU2668446C1 (ru) * 2018-01-16 2018-10-01 Акционерное общество "Научно-исследовательский институт синтетического волокна с экспериментальным заводом" (АО "ВНИИСВ") Установка для получения сорбционно-фильтрующих нетканых материалов с улучшенными свойствами из растворов полимеров методом аэродинамического формования

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Publication number Publication date
NL6605750A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html) 1967-01-25

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