US3531688A - Static eliminator device - Google Patents

Static eliminator device Download PDF

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Publication number
US3531688A
US3531688A US704029A US3531688DA US3531688A US 3531688 A US3531688 A US 3531688A US 704029 A US704029 A US 704029A US 3531688D A US3531688D A US 3531688DA US 3531688 A US3531688 A US 3531688A
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United States
Prior art keywords
web
induction
component
static
energized
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Expired - Lifetime
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US704029A
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English (en)
Inventor
Richard A Jackson
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3M Co
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Minnesota Mining and Manufacturing Co
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Publication date
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Publication of US3531688A publication Critical patent/US3531688A/en
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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
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05F—STATIC ELECTRICITY; NATURALLY-OCCURRING ELECTRICITY
    • H05F3/00—Carrying-off electrostatic charges
    • H05F3/06—Carrying-off electrostatic charges by means of ionising radiation

Definitions

  • a device for eliminating the static charge from moving webs or the like which advantageously utilizes the characteristics of two basic types of static eliminators, i.e. an electrically or radioactivity energized static eliminator having selected relatively limited capacity and a non-energized induction static eliminator in combination.
  • the combination device exhibits a substantially higher ionization current capability than either of the components, which is to an extent self-adjusting. Initially the induction component acts on the web reducing the web potential to a value which does not exceed the threshold potential of the induction component. Next, as the web passes the energized component, the web potential is further reduced to a desired level.
  • This invention relates to an apparatus for eliminating static charge from moving webs such as, for example, those used in plastic or paper coating, bagging, or laminating operations.
  • static eliminators may be categorized in two classes, namely, induction type static eliminators and energized static eliminators.
  • Induction, or non-powered, units generally consist of either grounded needles or metallic brushes suspended above the web surface to be neutralized.
  • Induction units are effective only if the web potential is sufficiently high to ionize the atmosphere between the needle points and the Web, to allow neutralization of the charge on the web surface.
  • the induction device is effective only at relatively high web potentials. For example, at web potentials below about 5 to kilovolts an Patented Sept. 29, 1970 induction static eliminator will not ordinarily function to provide the necessary ionization to neutralize the static charge.
  • Energized static eliminators may be further categorized as to what source of energy is applied to ionize the air.
  • Electrically powered units are generally similar in construction to the induction static eliminators wherein the needles are connected either directly or capacitively to a high voltage AC power supply which causes ionization in the air gap between the needle points and a proximity ground. This voltage can range from 5,000 to 15,000 volts and even higher.
  • Electrically powered units are generally effective to dissipate the static charge from webs with low potentials which are of themselves not sufficient to effect the necessary ionization by an induction static eliminator between the web and the needles.
  • powered static eliminators may be effective where induction units are not, due to low web potentials.
  • the pos- Sibility of ignition of solvents in the event of electrical breakdown of powered static eliminators often precludes their use in flammable atmospheres. Further, there is a definite shock hazard.
  • Radioactively energized static eliminators i.e. those in which ionization of air is effected by the interaction of alpha, beta, or gamma radiation, are also effective at low web potentials where the non-energized (induction) units are not.
  • the maximum ionization current produced by a nuclear static eliminator depends on the amount of radioactivity which the device contains and decreases as the radioactivity decreases with the half life of the radioisotope employed. Obviously, if only a nuclear unit is to be employed to neutralize low web potentials, the amount of radiation required to effect ionization will crease substantial problems of safety as well as cost.
  • the invention provides a device comprised generally of a first component which has a limited ionization-current capability (i.e. a nuclear or electrically powered component) which operates at low web potentials and a second component which responds to the web potential (i.e. an inductionstatic-eliminator).
  • a limited ionization-current capability i.e. a nuclear or electrically powered component
  • a second component which responds to the web potential (i.e. an inductionstatic-eliminator).
  • the combination device of the invention thus provides a substantially higher ionization current capability than either component could provide separately.
  • the apparatus is both safe and highly effective.
  • the apparatus of the invention for eliminating static charge from a moving web or the like comprises in combination an induction means including a plurality of elongated, parallelly-extending, electrically conductive and grounded members adapted to be positioned at a predetermined distance from said web for effecting an ionization of the atmosphere between the surface of the Web and said members when the static charge therebetween exceeds the ionization potential of said atmosphere so as to neutralize a portion of said static charge as the web moves relative to said members at said predetermined distance, and an elongated, electrically conductive, energized means positioned at a spaced distance from and in close proximity to the end points of the grounded members of said induction means to act upon the portion of the web which has passed by said induction means so as to effect an ionization of the atmosphere between the surface of the web and said conductive means for neutralizing the static charge from said web remaining after the web has passed by said induction means, the spaced distance being at least equal to the length of said elongated members of the induction means.
  • FIG. 1 is a perspective schematic view in partial crosssection of a combination induction and radioactively energized static eliminator for moving webs;
  • FIG. 2 is a diagrammatic sketch of another embodiment of the invention wherein the energized component thereof is comprised of an electrically powered static eliminator;
  • FIG. 3 is a graph showing the individual and combined effectiveness of a combination of radioisotope energized and inductive static eliminators.
  • FIG. 4 is a similar graph showing the individual and combined effectiveness of low-capacity electrically powered and inductive units.
  • FIG. 1 illustrates a static elimination device 10 for a moving web 12, whose direction of movement is indicated by the arrow, which comprises basically two components in combination, namely, a first elongated induction component 14 including a plurality of elongated, parallellyextending, electrically conductive and grounded members 16 (e.g.
  • wire needles held in electrically conductive support 17 adapted to be positioned at a predetermined distance 18 from the surface of the moving web and a second, elongated, electrically conductive, radioactivity energized component 20 positioned at a spaced distance from, and in close proximity to, the elongated members 16 (needles) of the induction component to act upon the portion of the web 12 which has passed by and has been acted upon by the induction component.
  • the spaced distance which separates the radioactivity energized component 20 from the end points of the elongated members 16 (needles) of the induction component must be at least equal to the length of the elongated members (needles) of the induction component.
  • the needles shown are constructed with a coiled, spring-like shank so that they can be deflected if contacted by a moving object.
  • the induction component 14 and the radioactivity energized component 20 are integrally connected by means of a common mounting member 22.
  • a nonconductive shield 24 eg of plastic is optionally mounted on the induction component parallel to and extending along and beyond the length of the elogated members 16 to protect said members from coming into contact with the web.
  • the radioactivel energized component 20 is comprised basically of U-shaped elongated metal member housing a radioactive source 26, preferably in the form of a compact monolayer of a multitude of discrete microspheroidal particles (not shown) containing e.g. about 18 millicuries of polonium per foot of length.
  • the energy-emitting face 28 of the radioactively energized component is provided with a metal screen member 30 to prevent damage to the radioactive source while allowing radiation to pass through freely.
  • radioactive materials such as americium krypton (contained in a tube), promethium and the like.
  • FIG. 2 illustrates diagrammatically another embodiment of the invention, wherein the energized component includes a bar 32 which is substantially similar to the induction component 14 but wherein the elongated needle members 34 thereof are connected either directly or capacitively to a high voltage power supply 36. Said energized component is provided with a proximity ground 38 which is electrically connected to the induction component 14.
  • both components will extend practically across the entire width of the web and will be positioned above the We l) or other workpiece in accordance with the particular conditions encountered. In specific instances it will be necessary to so position the device, and to provide such energization of the energized means, as to accomplish the required neutralization of the charge. The actual values will depend on web speed and the web potential and capacitance of the system.
  • the effect of the above combination device is that as the web moves past the needles of the induction component, a portion of the static charge on the web surface is neutralized when the web potential between the needle points and the web surface exceeds the ionization potential of the atmosphere therebetween. Next, as that portion of the web which has been acted upon by the induction component passes 'by the energized component, the residual static charge is neutralized by the energized component.
  • the maximum residual web potential after passing by the induction component, is the threshold potential for the energized component.
  • the energized component then requires only sufficient ionization current to reduce this residual potential to a desired level. This reduces the radioactivity requirement (in the case of a nuclear component) or the ionization current requirement (in the case of an electrically powered component) required to reduce this residual potential to a desired level.
  • the apparatus of the invention is responsive to fluctuations in charge.
  • the induction component becomes more effective as the level of charge and the web potential increase and is a self-adjusting part of the combination, maintaining the Web potential at a level equal to or less than the threshold potential of the induction component (said threshold potential being equal to the web potential at which the induction component begins to neutralize the charge).
  • the concomitant operation of the energized component insures that the residual web potential will be reduced to the desired level.
  • Apparatus for eliminating static charge from a moving web or the like comprising in combination:
  • an induction means including a plurality of elongated. parallelly extending, electrically conductive and grounded members having endpoints adapted to be positioned at a predetermined distance from said web for effecting an ionization of the atmosphere between the surface of the web and said members when the static charge therebetween exceeds the ionization potential of said atmosphere so as to neutralize a portion of said static charge as the web moves relative to said members at said predetermined distance,
  • a U-shaped elongated member housing a radioactive source adapted to emit alpha radiation from the Open end of said U-shaped elongated member in a direction substantially perpendicular to and toward said web,
  • said U-shaped member positioned in close proximity to said endpoints of the elongated members of said induction means, but not closer than a distance equal to the length of said elongated members, to act upon that portion of the web which has passed by said in duction means so as to eflect an ionization of the atmosphere between the surface of the web and said radioactive source, said radioactive source comprising polonium in the form of a compact monolayer of a multitude of discrete microspheroidal particles. 5 2. The apparatus in accordance with claim 1 wherein said U-shaped elongated member is positioned in close proximity to the endpoints of the elongated members of said induction means at a distance about equal to the length of said elongated members.

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  • Health & Medical Sciences (AREA)
  • General Health & Medical Sciences (AREA)
  • Toxicology (AREA)
  • Elimination Of Static Electricity (AREA)
US704029A 1968-02-08 1968-02-08 Static eliminator device Expired - Lifetime US3531688A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US70402968A 1968-02-08 1968-02-08

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US3531688A true US3531688A (en) 1970-09-29

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US704029A Expired - Lifetime US3531688A (en) 1968-02-08 1968-02-08 Static eliminator device

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US (1) US3531688A (https=)
JP (1) JPS512794B1 (https=)
AT (1) AT294228B (https=)
BR (1) BR6906223D0 (https=)
CH (1) CH495681A (https=)
DE (1) DE1905237A1 (https=)
FR (1) FR2001548A1 (https=)
GB (1) GB1250274A (https=)
NL (1) NL6901418A (https=)
SE (1) SE337911B (https=)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3818545A (en) * 1971-08-25 1974-06-25 Nuclear Radiation Dev Inc Radioactive static electricity eliminator
JPS50103647U (https=) * 1974-01-29 1975-08-26
US4438479A (en) 1981-03-13 1984-03-20 Falcon Safety Products, Inc. Self-contained anti-static adapter for compressed gas dust blowing devices

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5993482A (ja) * 1982-11-19 1984-05-29 Fuji Photo Film Co Ltd 除電方法
DE19938600C2 (de) * 1999-08-14 2002-07-18 Lemo Maschb Gmbh Entladungsregelung

Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1243262A (en) * 1916-04-24 1917-10-16 Clarence J Coberly Motion-picture camera.
US1735494A (en) * 1925-02-12 1929-11-12 Chapman Electric Neutralizer C Neutralizer bar
US2048490A (en) * 1934-08-16 1936-07-21 Radium Luminous Corp Static neutralization
US2264683A (en) * 1939-04-27 1941-12-02 Western Union Telegraph Co Method of and means for neutralizing electrostatic charges on moving tapes and the like
US2333213A (en) * 1942-02-02 1943-11-02 Slayter Games Static eliminator
US2479882A (en) * 1946-03-14 1949-08-23 United States Radium Corp Radioactive metal products and method for manufacturing
DE886180C (de) * 1951-10-19 1953-08-13 Siemens Ag Verfahren und Einrichtung zur Beseitigung elektrostatischer Ladungen auf elektrisch nichtleitenden Stoffen
DE954185C (de) * 1954-07-06 1956-12-13 Dr Heinz Haase Vorrichtung zur Beseitigung unerwuenschter elektrostatischer Aufladungen unter Ausnutzung der Spitzenwirkung
US3264473A (en) * 1963-06-26 1966-08-02 Marquardt Corp Radiation sterilization device with uniformly distributed beta emitters
US3396917A (en) * 1966-03-01 1968-08-13 Du Pont Method for unwinding rolls

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1243262A (en) * 1916-04-24 1917-10-16 Clarence J Coberly Motion-picture camera.
US1735494A (en) * 1925-02-12 1929-11-12 Chapman Electric Neutralizer C Neutralizer bar
US2048490A (en) * 1934-08-16 1936-07-21 Radium Luminous Corp Static neutralization
US2264683A (en) * 1939-04-27 1941-12-02 Western Union Telegraph Co Method of and means for neutralizing electrostatic charges on moving tapes and the like
US2333213A (en) * 1942-02-02 1943-11-02 Slayter Games Static eliminator
US2479882A (en) * 1946-03-14 1949-08-23 United States Radium Corp Radioactive metal products and method for manufacturing
DE886180C (de) * 1951-10-19 1953-08-13 Siemens Ag Verfahren und Einrichtung zur Beseitigung elektrostatischer Ladungen auf elektrisch nichtleitenden Stoffen
DE954185C (de) * 1954-07-06 1956-12-13 Dr Heinz Haase Vorrichtung zur Beseitigung unerwuenschter elektrostatischer Aufladungen unter Ausnutzung der Spitzenwirkung
US3264473A (en) * 1963-06-26 1966-08-02 Marquardt Corp Radiation sterilization device with uniformly distributed beta emitters
US3396917A (en) * 1966-03-01 1968-08-13 Du Pont Method for unwinding rolls

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3818545A (en) * 1971-08-25 1974-06-25 Nuclear Radiation Dev Inc Radioactive static electricity eliminator
JPS50103647U (https=) * 1974-01-29 1975-08-26
US4438479A (en) 1981-03-13 1984-03-20 Falcon Safety Products, Inc. Self-contained anti-static adapter for compressed gas dust blowing devices

Also Published As

Publication number Publication date
BR6906223D0 (pt) 1973-01-16
NL6901418A (https=) 1969-08-12
DE1905237A1 (de) 1969-08-21
FR2001548A1 (https=) 1969-09-26
AT294228B (de) 1971-11-10
DE1905237B2 (https=) 1972-11-16
JPS512794B1 (https=) 1976-01-28
CH495681A (de) 1970-08-31
GB1250274A (https=) 1971-10-20
SE337911B (https=) 1971-08-23

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