US3745413A - Ionizing apparatus - Google Patents

Abstract

In apparatus for generating and applying ionic charges to a web of film or the like operating in an explosive atmosphere of solvent vapor comprising an ionizer, a source of electrical energy connected to the ionizer, and means for supplying a stream of gas to the ionizer, the improvement comprising an air motor driving an electrical generator for supplying energy to the ionizer, and a single source of air under pressure connected both to the air motor and to the ionizer. Upon failure of air supply to the ionizer the motor automatically stops so as to discontinue the supply of electrical energy to the ionizer and avoid an explosion of the solvent vapor. Additionally a pressure responsive switch acts to open the circuit to the ionizer if the gas pressure decreases in the conduit leading to the ionizer.

Description

United stateS Patent 1 PRESSURE I TC H TRA IVSFORMER Whitmore July 10, 1973 IONIZING APPARATUS Primary Examiner-J. D. Miller Assistant Examir'zer-Harry E. Moose, Jr. [75] Inventor S g whmnore Rochester Attorney-W. O. Hodson, S. W. Gremban, William T.

French et al. [73] Assignee: Eastman Kodak Company,

Rochester, NY. [57] ABSTRACT 22 Filed; 1 1971 ln apparatus for generating and applying ionic charges to a web of film or the like operating in an explosive at- [211 Appl' 208,970 mosphere of solvent vapor comprising an ionizer, a Rehged Application Data source of electrical energy connected to the ionizer, I [63] Continuation of Ser. No. 63 140 Aug. 12 1970. and .means for Supplymg .stream gas to thqmnizer the improvement comprising an air motor driving an [52] us. Cl 317/4 317/262 R electrical generator for supplying energy to the ionizer, [51] Int C H05 3/06 and a single source of air under pressure connected [58] Field 4 262 R both to the air motor and to the ionizer. Upon failure of air supply to the ionizer the motor automatically [56] References Cited stops so as to discontinue the supply of electrical energy to the ionizer and avoid an explosion of the solvent UNITED STATES PATENTS vapor. Additionally a pressure responsive switch acts to 1,360,654 11/1920 Littlefield 317/3 open the ircuit to the ionizer the gas pressure decreases in the conduit leading to the ionizer.

4 Claims, 2 Drawing Figures All? //V ION/25R PAIENIED JUL 1 0191s THOMAS c. WH/TMOR INVENTOR. flaw 1 IONIZING APPARATUS This is a continuation of application Ser. No. 63,140, filed Aug. 12, 1970.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel apparatus for generating and applying ionic chargesto a web of flexible di-electric material such as photographic film or paper, so as to neutralize a static charge thereon, or to establish a desired positive or negative charge. The invention is of particular value when a web coating operation is conducted in an atmosphere of organic solvent vapor which may explode if allowed to come in contact with a conventional ionizer. For example, organic solvents are employed in the coating of magnetic tape,and in the coating of photographic film and paper with subs, antistatic layers, antihalation layers and the like.

2. The Prior Art Ionizers have been used in the past to neutralize the static charge on a web such as photographic film or paper, or magnetic tape, or to adjust the static charge to a desired value and sign. In U.S. Pat No. 3,292,042 there is described a system wherein air is circulated through a charged grid electrode and then against an article. The air is normally supplied from one system,

and the high voltage electrical power supply from a different and unrelated system.

Reference is also made to my U.S. Pat. No. 3,396,308, the disclosure of which is incorporated by reference herein.

SUMMARY OF THE INVENTION In my improved ionizing system, an ionized non combustible gas such as air also is passed over a charge electrode and then against a web to be treated. Instead of using separate sources of air and electric power, however, the power is generated by .driving an electrical generator by an air motor driven by compressed air from a source which is also connected to the ionizer whereby air is passed over the charged electrode and against the web, thus improving efficiency and simplifying apparatus.

Even more important, my novel system provides an automatic fail-safe feature inasmuch as any failure of the air supply to the ionizer automatically shuts off the air motor and discontinues power generation.

THE DRAWING FIG. 1 of the drawing is a schematic view of exemplary alternating current ionizing apparatus embodying the principles of the invention; and

FIG. 2 is a schematic view of a part of apparatus for supplying a direct current to the ionizer instead of alternating current.

THE PREFERRED EMBODIMENTS Referring to the drawing, a web 11 of photographic film or paper base, or magnetic tape base, is passed into an enclosure 13, over rollers 15 and 17, and under a coating hopper 19 containing a pasty or fluid mixture of the material to be coated suspended in a volatile organic solvent, which is deposited onto the web. After coating, the web 11 leaves enclosure 13 and passes to subsequent finishing operations such as drying, calendering, slitting and spooling operations.

2 An ionizer 21 is positioned wtihin enclosure '13 adjacent to web 11 ahead of coating hopper19 for blowing ionized air against the'web. The sign and voltage are such as to neutralize thestatic change on the web or to reduce the charge thereon sufficiently so as to avoid the possibility of a static spark discharge occurring in the vaporous atmosphere inside enclosure 13 with resultant possible explosion.

THe ionizer 21 includes an electrode 23, which may be in the form of a grid, connected to a high voltage '(e.g., 3,0005,000 volts output) aPernating current transformer 25 which is energized b, a lower voltage (eg 80-l volts output) alternating current generator 27. Alternating current generator 27 is actuated by an air motor 31 supplied with air by a conduit 33 and having a discharge conduit 34 for exhaust air. Conduit 33 also is connected through a conduit 35 to the ionizer 21. Air from conduit 35 serves the dual purpose of preventing access of explosive vapors to electrode 23, and of acting as an ion transfer means through an orifice 36 which has about the same width as web 11.

If the supply of air through conduit 33 is interrupted for any reason, the flow of air to ionizer 21 also ceases, and an explosion or organic vapors could occur if the supply of energy to electrode 23 continued. In my apparatus, however, failure of the air supply stops the motor 31 immediately and the generation of electricity stops.

Even if the supply of air is only reduced to a point where insufficient air might enter ionizer 21 to prevent access of vapor, the circuit from generator 27 to transformer 25 is automatically interrupted by a pressure actuated switch 39 which is connected into conduit 35 and is set to operate at a selected reduced pressure.

Referring to FIG. 2, when direct current energization of electrode 23 is desired, the transfromer 25 can be replaced by a combined transformer-rectifier 41 which is interposed between generator 27 and ionizer 21 just as in FIG. 1. Thus, high voltage direct current of either positive or negative polarity can be supplied to the ionizer.

Among the web materials to which my invention can be applied are paper, cellulose triacetate, poly(ethylene terephthalate), and the like.

Air is the most practical gas for my invention because of its ready availability. However, it is to be understood that other non explosive, non combustible, and ionizable gases can be used successfully and are to be considered the functional equivalents of air, e.g., nitrogen,

or argon.

The invention has been described in detail with particular reference to preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention.

1 claim:

1. In an apparatus for generating and applying ionic charges to amaterial transported through an enclosure, the combination comprising:

an ionizer positioned in said enclosure adjacent the material;

a source of electrical energy connected to said ionizer and adapted when enabled to provide electrical energy to said ionizer;

a gas driven motor drivingly coupled to said source of electrical energy and adapted when driven to enable said source to provide electrical energy to said ionizer;

conduit means having a first conduit connected to said source of electrical energy, a separate second conduit connected to said motor, and a third conduit connected to said first and second conduits; and

a gas source for supplying gas to said third conduit,

said gas adapted when supplied above a predetermined pressure to simultaneously drive said motor, enable said source of electrical energy, and supply an ionized stream of gas to the material, wherein said material is a Web having a coating containing a vaporizable explosive organic solvent which forms a solvent vapor atmosphere in said enclosure, and wherein said stream of gas prevents access of solvent vapor to said ionizer, and when supplied below said predetermined pressure to disable said motor and said source of electrical energy so that electrical energy is no longer provided to said ionizer.

2. In apparatus in accordance with claim 1, pressure responsive means in communication with said first conduit and operable at a predetermined reduced pressure therein, and means controlled by said pressure responsive means operable to disable said source of electrical energy upon the occurrence of such reduced pressure.

3. In apparatus in accordance with claim 1, said source of electrical energy comprising an alternating current generator coupled to said motor; and

a transformer electrically connected to said altemating current generator and to said ionizer.

4. In apparatus in accordance with claim 1, said source of electrical energy comprising an alternating current generator coupled to said motor, and a transformer and rectifier electrically connected to said alternating current generator and to said ionizer for supplying direct current to said ionizer.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION.

Patent No. 3,745,413 Dated July 10, 1973 Inventor(s) Thomas C. Whitmore It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 2, line 4, delete "change" and insert-charge-.

Column 2, line 25, delete "or and insert--of--.

Column 3, line 9, delete "adapted" and insert- -being effective- Signed and sealed this 9th day of July 197A.

(SEAL) Attest:

MCCOY M. GIBSON, JR. Attesting Officer C. MARSHALL DANN Commissioner of Patents 225 UNITED STATES P TENT OFFICE CERTIFICATE OF CORRECTION.

Patent No. 1,745,413 ared July 10, 1973 lnv nt fls) Thomas C. Whitmore It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 2, line A, delete "change" and insert--charge--.

Column 2, line 25, delete "or and insert--0f-.

Column 3, line 9, delete "adapted" and insert--being effective- Signed and sealed this 9th day of July 197A.

(SEAL)- Attest:

MCCOY M. GIBSON, JR. Attesting Officer C. MARSHALL DANN Commissioner of Patents

Claims (4)

1. In an apparatus for generating and applying ionic charges to a material transported through an enclosure, the combination comprising: an ionizer positioned in said enclosure adjacent the material; a source of electrical energy connected to said ionizer and adapted when enabled to provide electrical energy to said ionizer; a gas driven motor drivingly coupled to said source of electrical energy and adapted when driven to enable said source to provide electrical energy to said ionizer; conduit means having a first conduit connected to said source of electrical energy, a separate second conduit connected to said motor, and a third conduit connected to said first and second conduits; and a gas source for supplying gas to said third conduit, said gas being effective when supplied above a predetermined pressure to simultaneously drive said motor, enable said source of electrical energy, and supply an ionized stream of gas to the material, wherein said material is a web having a coating containing a vaporizable explosive organic solvent which forms a solvent vapor atmosphere in said enclosure, and wherein said stream of gas prevents access of solvent vapor to said ionizer, and when supplied below said predetermined pressure to disable said motor and said source of electrical energy so that electrical energy is no longer provided to said ionizer.

2. In apparatus in accordance with claim 1, pressure responsive means in communication with said first conduit and operable at a predetermined reduced pressure therein, and means controlled by said pressure responsive means operable to disable said source of electrical energy upon the occurrence of such reduced pressure.

3. In apparatus in accordance with claim 1, said source of electrical energy comprising an alternating current generator coupled to said motor; and a transformer electrically connected to said alternating current generator and to said ionizer.

4. In apparatus in accordance with claim 1, said source of electrical energy comprising an alternating current generator coupled to said motor, and a transformer and rectifier electrically connected to said alternating current generator and to said ionizer for supplying direct current to said ionizer.

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