US2989882A - Method and apparatus for slitting paper webs - Google Patents

Description

June 27, 1961 R. REME R 2,989,882 A METHOD AND APPARATUS FOR SLIITING PAPER WEBS Filed Sept. 11, 1956 F'IEA- Patented June 27, 1961 2,989,882 METHOD AND APPARATUS FOR SLI'ITING PAPER WEBS Robert K. Remer, Elgin, Ill., assignor to Tribune Company, Chicago, Ill., a corporation of Illinois Filed Sept. 11, 1956, Ser. No. 609,215 14 Claims. (Cl. 83-13) This invention relates to the production of paper such as newsprint in paper mills, and more particularly to the slitting of the web prior to winding it into rolls. In normal methods of slitting a great deal of lint and dust is created which deposits on the web, in the form of fiber, fuzz, or whiskers. Such extraneous material often gathers into wads forming What are known as hickies on the paper sheet. These can seriously mar the printed surface, particularly in the case of ofi'set printing, since the hickies can be transferred to the blanket and in the printing process the imperfection in the printing resulting therefrom will be repeated on sheet after sheet in the same place. This necessitates frequent cleaning or washing up of the blankets, plates and ink rollers, with consequent loss of time and increase in labor.

Some mills use compresed air, a vacuum or a brush to remove the dust and lint from the paper, but due to the high static charge which usually exists on the paper, there is a tendency for dust particles or lint to stick to the surface so that they are not effectively removed by existing methods. I have provided means and a method for reducing or eliminating the static as set forth in my application, Serial No. 612,081, filed September 11, 1956, and this tends to alleviate the problem to some extent. However, the problem could be prevented from arising or greatly minimized if the formation of lint and dust in the slitting of the paper could be prevented, and it is accordingly the purpose of this invention to accomplish this result.

In accordance with the invention, I apply to the knives used for slitting the paper a non-friction lubricating solvent, in vapor form, which is redeposited on the slitted edge of the paper and plasticizes the edge so as to hold the lint, fuzz or whiskers in the sheet rather than allowing them to fly into the air and become trapped between the sheets as they are wound onto the customary web roll.

(It is generally understood that paper in its natural state posseses an excess of electrons, and thus is negatively charged. In the usual course of conducting a paper web through a slitting or cutting machine at high speeds, the friction of the paper being drawn over rollers in such a machine creates kinetic electricity in the paper web tending to increase the naturally existing negative charge carried by the paper web. Since dust is naturally attracted to negatively charged bodies, the lint, dust and fuzz formed by slitting the paper web is strongly attracted to the paper web.

The chemicals used to produce the vapor in this paperslitting process have anti-static properties as will hereinafter more fully appear.

The invention resides primarily in the method whereby the formation of slitter dust or fine fibers which tend to deposit themselves on the web is prevented, but a secondary object of the invention is to provide an apparatus which is particularly well adapted to this purpose.

Other objects and advantages of the invention will be apparent from the following description, taken in connection with the accompanying drawings, in which:

FIG. 1 is an elevational view, partly in section, of my apparatus, showing the manner in which the method of the invention may be carried out; and

FIG. 2 is a top plan view thereof.

As shown in FIG. 1, the web is passed through a slitter comprising shafts 11 and 12 on which two pairs of slitter knives are carried. The knife 15 of one pair (shown at the right in FIG. 1) is secured to the shaft 12 by means of a hub 13 and set screw 14. The other knife, identified by the numeral 18, of this pair is secured-to the shaft 11 by means of a hub 16 and set screw 17. The knives of the other pair are similarly attached to said shafts, such knives and their hubs and set screws being identified by similar numerals with prime markings. The pairs of knives are suitably spaced to obtain the desired width of webs for winding into the customary newsprint rolls for newspaper printing, it being understood that the paper is produced in the mill on wide screens and felts resulting in a web of greater width than that desired for the rolls on which the paper is wound for shipment and for handling in the newsprinting operations.

Beneath the right-hand pair of knives (viewing FIG. 1), I provide a vaporizing chamber, generally identified by the numeral 19. A second vaporizing chamber is pro vided beneath the pair of knives 15', 18, and since this chamber is identical to the chamber -19, the parts are identified with the same numerals but with prime markings. Therefore, for the most part, one unit only will be described, but it will be understood that the description applies in the same manner to the other unit except where otherwise indicated.

The chambers 19 and 19 are supported beneath the slitter by any suitable means (not shown).

Water is supplied to the chamber 19 through a pipe 20 having a T-joint 21 therein connecting the same through a valve 22 with a water inlet pipe 23. A valve 24 is also provided in the pipe 20.

When the chamber 19 has been filled to desired level, the valve 22 is closed. Cationic chemicals, to be hereinafter described, are added to the water by placing the same in the chamber 19 before or after the water is admitted.

A headspace is provided in the chamber 19 above the liquid level and an opening 26 is provided in a cover 40 for said chamber. Said opening 26 is in the form of a narrow slit with flanges 41 extending upwardly from the cover at the edges of said slit. The knife 15 is disposed in the slit 26, as shown in FIG. 1 of the drawings.

In order to normally keep the liquid at substantially the same level in the two chambers, standpipes 27 and 27 are provided in said chambers, respectively, and are supported by an interconnecting pipe 29 in which valves 28 and 28' are provided. Also upwardly-turned overflow pipes 32 and 32 are provided in the chambers 19 and 19', respectively, at substantially the desired liquid level.

A heating element 30 is provided in the bottom of the chamber 19 and is connected with a suitable source of electrical energy by wires 31. v

A conductor member 33 extends through the wall of the chamber 19 into the solution 25 and has a wire conductor 34 leading therefrom through which any static charges formed within said chamber will be dissipated.

Provision is made for admitting steam to the chambers 19 and 19' through the pipes 20 and 20 after the water valves 22 and 22' have been closed. A valve 35 in a pipe 42 leading from a source of steam (not shown) is provided for controllingthe admission of the steam.

An extended part of the pipe 20 is connected with the pipe 20 by means of a T joint 36 so that the steam may be admitted to both chambers from the pipe 42 through the valve 35.

The heating of the solution 25 in the vaporizing chambers causes the formation of vapor 38 in the upper part of the chambers and the knives 15 and 15', which rotate in this vapor in the slits 26 and 26', become thoroughly coated with the vapor and/or its condensate, which is transmitted to the paper as the knives cut therethrough and to the co-acting knives 18 and 18'. By virtue of the vapor being positively charged and the paper negatively charged, the vapor and/or its condensate is easily deposited upon the edge of the paper, where it plasticizes gile paper and prevents the formation of lint, dust and 22. While a number of positively charged or cationic chemicals will serve to provide a proper solution for the vaporizing chambers, the following may be given as examples: quaternary fatty amines such as Armac C; quaternary ammonium compounds such a cetyl pyridinium chloride; and Sapamine WL which is an aliphatic tertiary ammonium acetate compound. It should be noted that Armac C is a trade name by which the manufacturer, Armour Chemical Division, identifies the acetic acid salts of its fatty amines, which salts may be represented by the formula:

in which R represents an alkyl group, derived from fatty acids, containing 8 to 18 carbon atoms. Polyethylene glycols such as Carbowax 1000, 2000, 4000 or 6000 may desirably be used as plasticizers in the solution.

A proper solution for use in the practice of my method may consist of water containing from 1% to 20%, by volume, of a cationic chemical, such as one of those mentioned above.

The heating of the solution and the admission of the steam to the chambers 19 and 19 create the vapor indicated at 38 and 38', through which the knives 15 and 15', respectively, rotate.

Since certain changes can be made both in the procedures and the apparatus above described without departing from the spirit or scope of the invention, it is intended that the disclosures herein shall be interpreted as illustrative and not in a limiting sense.

I claim: I

1. A method for slitting paper comprising applying to said paper as it is cut an organic cationic chemical fluid so as to prevent the formation of loose fibers, lint or fuzz.

2. A method for slitting paper comprising vaporizing a solution containing an organic vaporizable cationic chemical and applying the resulting fluid thus formed to the paper as it is cut to prevent the formation of loose fibers, lint or fuzz.

3. A method for slitting paper comprising vaporizing a solution containing an organic vaporizable chemical and coating the blades used to slit said paper with the resulting fluid so that such fluid is transferred from said blades to the paper as it is cut, thus preventing the formation of loose fibers, lint or fuzz.

4. A method of slitting paper comprising vaporizing a solution containing an organic vaporizable cationic chemical and coating the blades used to slit the paper with the resulting fluid so as to prevent said blades from creating static electricity as the paper is slit.

5. A method for slitting paper without forming lint or dust, comprising vaporizing a solution containing an organic vaporizable cationic chemical and applying the resulting fluid to the paper as it is cut. I

6. A method for slitting paper without forming lint or dust, comprising vaporizing a solution consisting of water containing from 1% to 20% by volume of a vaporizable organic cationic chemical and applying the resulting fluid to the paper as it is cut.

7. A method of slitting newsprint which comprises passing a. web thereof to be slit between cutter blades andcontinuously applying to such blades a vapor of an organic vaporizable cationic solution.

8. A method of slitting newsprint which comprises passing a web thereof to be slit between cutter blades as at least one thereof is rotated in a vapor bath produced by heating an organic vaporizable cationic solution.

9. A method of slitting newsprint which comprises passing a web thereof to be slit between cutter blades as at least one thereof is rotated in a vapor bath produced by heating and injecting steam into an organic vaporizable cationic solution.

10. A method of slitting paper which comprisespassing a web thereof to be slit between cutter blades as at least one thereof is rotated and coating a rotating cutter blade with vapor formed by heating and injecting steam into an organic vaporizable cationic solution.

11. In combination with a paper web slitter having rotating cutter blades, an apparatus for coating the blades of the slitter with vapor from a cationic solution, comprising: a vaporizing chamber for containing said solution, a heating unit arranged to heat the solution in said chamber, said vaporizing chamber having a narrow opening in the top thereof into which one of said rotating blades of the slitter may extend and pass through the vapor formed in the chamber, whereby a coating adapted to counteract the formation of static will be applied to said blade and by it to the web.

12. In combination with a paper web slitter having rotating cutter blades, an apparatus for coating the blades of the slitter with vapor from a cationic solution, comprising: a vaporizing chamber for containing said solution, means for introducing water into said vaporizing chamber to form the solution, a heating unit arranged to heat the solution in said chamber, said vaporizing chamber having a narrow opening in the top thereof into which one of said rotating blades of the slitter may extend and pass through the vapor formed in the chamber, whereby a coating adapted to counteract the formation of static will be applied to said blade and by it to the web.

13. In combination with a paper web slitter having rotating cutter blades, an apparatus for coating the blades of the slitter with vapor from a cationic solution, comprising: a vaporizing chamber for containing said solution, means for introducing water into said vaporizing chamber to form the solution, a heating unit arranged to heat the solution in said chamber, means for injecting steam into the solution to further heat and vaporize the same, said vaporizing chamber having a narrow opening in the top thereof into which one of said rotating blades of the slitter may extend and pass through the vapor formed in the chamber, whereby a coating adapted to counteract the formation of static will be applied to said blade and by it to the web.

14. A method of slitting paper wherein the slitting blades are caused to be coated with a vapor formed from a heated solution comprising water containing a cationic chemical taken from the group consisting of quaternary fatty amines and quaternary ammonium compounds.

References Cited in the file of this patent UNITED STATES PATENTS 341,895 Edmunds May 18, 1886 1,036,173 Arey Aug. 12, 1912 1,368,933 Hutchinson Feb. 15, 1921 1,472,450 Yetter Oct. 30, 1923 2,067,174 Dickie et a1 Ian. 12, 1937 2,393,863 Myers Jan. 29, 1946 2,421,363 Young May 27, 1947 2,658,427 Doot Nov. 10, 1953 2,668,785 Jefierson et al. Feb. 9, 1954 2,729,576 Trusler Jan. 3, 1956

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