US1678869A - Static dissipator - Google Patents

Description

July 31, 1928. 1,678,369

M. MORRISON STATIC DISSIPATOR Filed Deal/ ZSheets-Sheet l INVENTOR fihizforci Nor/2 52m,

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M. MORRISON STATIC DISSIPATOR Filed Dec. 1. 1922 2 Sheets-Sheet 2 Patented July 31, 1928..

UNITED STATES MONTFORD MORRISON, OF CHICAGO, ILLINOIS.

STATIC DISSIPATOB.

Application filed December 1, 1922. Serial No. 604,140.

This invention relates to a new and improved static dissipator and more particularly to an apparatus for removingor diswith static electricity. This charge causes the sheets to adhere to each other and to adhere to other surfaces making it difiicult to handle them and to properly adjust them for printing. A charge upon any one sheet will not be great in amount, but in handling a large number of sheets during the rapid operation of a press, the piles of sheets may become relatively heavily charged. This charge is acquired in various ways during the operations of handling and printing upon the sheets, or the sheets may be somewhat charged before operation is begun upon them. Similar difficulties occur in spinning mills in connection with thread and in paper mills where paper is surfaced and coated or calendered.

Certain methods have heretofore been developed for the elimination of this static by causmg the charged material to pass through a field generated by a wire charged with alternating current electricity under a hi h potential. Such devices, therefore, invo ve the placing of a conductor of high tension electricity in relatively close proximity to the material from which the charge is to be removed. This placing of the high tension wire or similar conductor is a source been referred to. Ionized air is a very maof considerable fire risk since the material operated u on is of a highly inflammable nature. comparatively small clearances between the conductor and material worked upon. A further difliculty lies in the danger to workers who may accidentally come in contact with the conductor. In addition, an accident ma cause the conductor to become grounde to the press or other apparatus and thus become a source of difiiculty or danger.

Static electricity is gradually dissipated through the air but under normal air conditions this dissipation is not sufficiently rapid to be of any value in eliminating static in connection with the operations which have terially better conductor of electricity than air in its normal state. There are a number so it is necessary to work with of methods of ionizing air among which is the X-ray method, and the air at the edge of a flame is also highly ionized. However, neither of these methods is particularly adapted for commercial application to types of apparatus mentioned.

A further method of ionizing air comprises passing it between electrical conductors having a high potential difference. One of the conductors will preferably be impressed with a current of high potential whlle the second conductor will be grounded. The air between the two conductors will be lonlzed by the flow of electrons caused by the difference in potential, and apparatus involvmg this method of operation may be constructed in which the high tension conductor is completel enclosed, thus eliminating the fire hazar and also the danger to workers. A flow of electrons is also caused by a heated or incandescent conductor, and this method may be used alone or in combination with the potential difference.

It is an object of the present invention to provide a new and improved method of static dissipation and apparatus for carrying out the method, comprising the formation and use of ionized air as a conducting and discharging medium for the static.

It is a further object to provide a method whereby the ionized air is created adjacent the work and the material to be discharged and is brought adjacent to or in contact with the materia It is also an object to provide a method of this character in which all high tension electrical conductors are enclosed thus minimizing the hazard caused by the use of such current when high tension current is used as a means of producing ionization.

It is an additional object to provide an apparatus adapted for carrying out a method which apparatus is simple in design and construction and which is automatic in its operation and which may be readily applied to existing installations without material alterations therein.

Other and further objects will appear as the descri tion proceeds.

In the rawings- Figure 1' is a diagrammatic showing of the circuits involved in my method and apparatus;

Fi ure 2 is a horizontal section through one orm of apparatus adapted for carrying out my met 0d;

Figure 3 is an elevation of the transformer shown in Figure 2, the cover being removed; and

Figure 4 is a longitudinal section of one form of casing adapted for use with the apparatus.

Referring first to Figure 1, an alternating current generator has been indicated at 7, the generator being connected by wires 8 and 9 to the primary 10 of a transformer. The secondary 11 of the transformer is connected by wire 12 to the shield 13 which is located in proximity to the material 14 which is to have its static charge removed. The opposite side of the secondary 11 is connected to wire 15 which passes through the center of the shield 13. As shown in the diagram, this wire forms a closed circuit through the coil 17. The shield 13 is grounded at 18. The shield is provided with a plurality of perforations 19 located adjacent the material being worked upon.

The particular form of apparatus shown in Figures 2 to 4 comprises a transformer by any suitable means (not shown) to the circuit of an alternating current generator. The inner end of the secondary is grounded to the core. The outer end is connected to the wire 26 which is held centrally in the casing 21 by the insulated support ring 27 and insulator 28. Insulator 28 is screwed into a connector 29 which latter is of conducting material and connects the shield 21 and the core 23 by means of the cover 30 of the transformer. The casing 21 is provided with a plurality of perforations 31 and is lined with insulating material 32 which is correspondingly perforated. As

best shown in Figure 4, the perforations in the insulating layer 32 are smaller than the perforations 1n the casing 31 and the perforations are concentrically located. It will be understood that the casing 21 is formed of conducting materials In the operation of the apparatus as schematically outlined in Figure 1, the alternating current is'generated and passed through the primary 10 of the transformer and creates a high voltage current in the secondary 11. One end of the secondary is connected to the wire 15. If the device is used solely for operation by a difference secondary and consequently a difference in potential exists between the wire 15 and shield 13, and this difierence in potential causes a flow of electrons between the wire and shield. If the end of the wire 15 be connected through the coil 17 as shown in the figure, a current flow will take place through the wire and the wire may be heated to any desired temperature or stage of incandescence. It is well known in the art that an incandescent conductor emits a flow of electrons. difference in potential will thus be added to.

The ionized air formed in the casing 13 will passthrough the perforations 19 adja cent to or into contact with the material 1 1 which is being worked upon. This flow may be caused by a blower, or a certain amount of flow will be induced merely by the rapid passage of the material adjacent the perforations. This ionized air is an efiicient conductor and will thus conduct away and dissipate the static charge impressed upon the material.

In the particular form of construction shown in Figures 2 to 1, the wire 26 is an equivalent of the wire 15 of the diagram. In this case theopposite end of the wire is not connected back to the secondary and the operation depends entirely upon the difference in potential. The casing 21 is connected to the opposite end of the secondary by means of the conductor 29, shield 30 and core 23, this connection being the equivalent of the wire 15 ofthe diagram. The nonconducting lining 32 is adapted to prevent the discharge ofgthe ionized air by direct contact with the grounded casing 21. This is further prevented by making the openings in the insulating material smaller than the opening in the casing 31 whereby the air flowing through the openings in the insulatingmaterial does not directly contact wlth the edges of the perforations in the casing. The desired flow of air is maintained by means of a blower which may be operated by any suitable means. The apparatus 1s completely enclosed and there are I10 ll1gl1 tension wires exposed.

The grounded shield cuts off the field about the central high potential wire and the material to have its static charge dissipated does not pass through an electrical field. It passes adjacent or in contact with a flow of lonized air and this air being an eflicient conductor neutralizes or dissipates or takes off the static charge.

While 'I have illustrated certain preferred embodiments of my invention, it is obviously capable of, modification to meet varying conditions. It is further to be understood that static dissipation by my ionization method may be carried out by other means and methods than those herein specifically The flow caused by the p illustrated. I contemplate such variations and changes as come within the scope of the appended claims.

I claim:

1. Apparatus for the dissipation of static electricity comprising a conductor, a source of high-tension electricity connectedto said conductor and to a second conductor enclosing the first conductor, an air gap between said conductors, openings in said second conductor whereby a1r passing through said air gap may pass from said gap into contact with the material to" be treated, and a nonconducting lining in said second conductor, said lining having openings of less area than the openings in the conductor and aligned therewith.

2. Apparatus for the distribution of static electricity comprising a conductor, a second conductor enclosing the first conductor but out of contact with it to provide an air gap and having an opening whereby air passing through said air gap may pass from said gap into contact with the material to be treated, a non-conducting lining in said second conductor, and a source of high-tension electricity connected to the first conductor and to the second conductor.

3. Electrical apparatus comprising a tubular member, a blower device directly secured to one end and a transformer located at the other end, a connector for mechani cally securing said transformer to said tubular member and for electrically connecting the core of the transformer to the tubular member, said transformer having one end of its secondary winding connected to its core, a conductor extending through said tubular member and connected to the other end of said secondary winding, means for insulating one end of said conductor from said tubular member and said blower, and an insulator threaded in said connector for enclosing the other end of said conductor.

Signed at Chicago, Illinois, this 27th day of November, 1922.

MON TFORD MORRISON.

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