US1957913A - Process for making paper - Google Patents

Description

May 8, 1934. c. w. SMITH I PROCESS FOR MAKING PAPER Filed Nov. 18, 1932 231168125-311981; l

l 71? (Smith May 8, 1934. c. w. SMITH PROCESS FOR MAKING PAPER Filed Nov 18 1932 2 Sheets-Sheet 2 Wziges/ Charla; 7/1 dnzilh Patented May 8 1934 UNITED STATES PATENT OFFICE 3 Claims.

The present invention relates to processes and apparatus for making paper; and its object is to provide an improved process for making a paper having great strength and a high degree of porosity; and, to provide improved apparatus for carrying out said process.

These and any other objects hereinafter appearing are attained by the process, and the pref erable apparatus, particularly described in the body of this specification, said apparatus being illustrated by the accompanying drawings, in which:

Figure 1 is a diagrammatic elevational side view of apparatus for carrying out my process for making paper, the flow box of said apparatus being shown in central vertical section;

Figure 2 is an enlarged central vertical sectional view of a portion of said flow box and adjacent parts;

Figure 3 is a horizontal sectional view thereof taken on line 33 of Figures 1 and 2;

Figure 4 is a vertical sectional view of certain rolls and a scraper blade of said apparatus, and an edgewise view of the paper sheet traveling on the rolls; and

Figure 5 is an edgewise view, somewhat diagratic in,character, of said sheet.

My process for making paper which shall have a high degree of porosity and also a high degree of strength, and a preferable apparatus whereby said process may be carried out, are as follows:

Fibrous paper stock, as bits of wood suitable for the purpose, is first treated in a water-com.

taining heater or Jordan engine for hydrating the fibres and rendering them toughand pliable, as well as for treating the same with such chemicals (as sizing, alum, coloring matter, etc.) as may be necessary or desirable. The mixture of said fibres and water may be screened, and then passes to the apparatus shown in Figure 1, entering the inlet 1 of the flow box 2 of the apparatus. Said mixture 3 includes an amount of water sufiicient to make the mixture flow freely and the elongated fibres 4 to readily float relatively to each other therein. This flow box .has a discharge vent 5 provided with a valve or slice 6, pivotally mounted at '7, for controlling the flow of the mixture through the vent. This slice has suitable means for opening said vent to the desired degree, as the rod 8 threaded in a bracket 9 and swivelled at 10 on the link 11 pivoted at 12 on the slice.

The slice has on its inner-under side an end lip 13 extending transversely of the flowing mixture. This lip is concave toward the flexible apron 14 carried by the bottom 15 of the flow box and supported by the roll 16. The fibres 4 in the flowing movement of the mixture through the flow box naturally assume a position parallel with the direction of such movement; but as the mixture nears the lip 13 the flowing movement is sufliciently retarded thereby and the mixture given by said lip a rotary movement to cause the fibres to float relatively to each other into mutually transverse or interlacing positions, as best indicated in Figure 3, so that when the mixture passes beyond the slice and is thereby spread into the thin paper lay 1'7, the fibres are interlaced as indicated at the right hand end of Figure 3.

This interlacing of the fibres thus provides a better lay, and produces a stronger paper when the fibres are felted together into the paper sheet, than if the fibres were disposed parallelly in the lay and sheet. As in ordinary practice the lay 17 passes oil of the apron 14 to be felted into paper on an endless belt 19 carried on and traveled by the roll 16 and couch roll 18. This belt is desirably of the wire screen form employed in a Fourdrinier machine and permits the water in the lay to sufliciently drain or be otherwise expelled therefrom during the lays travel by the belt.

The sheet now passes, as in ordinary practice, between pairs of rotating pressure rolls sufiicient in number (only one such pair 20, 21 being shown) to further expel the water and compress the sheet to the desired degree. The sheet now passes over a rotating dryer roll 22 and is smoothed thereon by the smoothing roll 23 and considerably compressed as indicated at 24 in Figure 4:. The roll 22 is heated, as by steam therein, to such a high degree as to transform the water in the sheets portion 24 into steam, whose expansion presses the sheets fibres apart thus opening the interstices between them. Said portion 24 adheres to this heated roll and is carried by its rotation into contact with the stationary blade 25 and is thereby s'craped from said roll. But in so doing the said portion 24 on reaching the blade is thereby crinkled crosswise or creped as seen at 26 in Figure 4. The result of this crinkling or creping process is to open such interstices particularly at their ends or mouths which are on the convex sides of the crepes, as indicated and exaggerated for cleamess) at 27 in Figure 5.

This creping process does not weaken the sheet, at least not materially, because it is then hot and still sufliciently wet to prevent the fibres from being broken by said process. The sheet is thus made more porous either by the said action of the expanding steam or by the creping process, or by both, as above described.

The sheet may now pass, as in usual practice, over other rotating drying rolls as indicated at 28, to thoroughly dry the same. These rolls are not heated to so high a degree as roll 22. They may be so related to said roll 22 in diameter or rotative speed as to take up any slack (as at 29) and to tauten or stretch the sheet longitudinally and thus eliminate the crinkled or creped formation entirely or to a desired degree. The sheet may then berolled as indicated at 30.

I claim:

1. A process for making a porous paper sheet which includes forming a wet web of paper stock fibres, heating the web to transform water therein to steam for opening interstices between the fibres by the expansion of the steam, creping the web transversely for further opening such portions of the interstices as are adjacent the externallyangled parts of the creped web, and then stretchingthe web longitudinally to straighten the same to a desired degree for further opening the opposite portions of said interstices.

2. A process for making a porouspaper sheet which includes forming a wet web of paper stock fibres, moving the web on a rotating roll heated to transform water in the web to steam for opening interstices between the fibres by the expansion of the steam, retarding the movement of the web on the roll relatively to the rotation of the roll'for creping the web transversely and further opening such portions of the interstices as are adjacent the externally-angled parts of the creped web, and then stretching the web longitudinally to straighten the same to a desired degree for further opening the opposite portions of said interstices.

3. A process for making a porous paper sheet which includes making a wet web of paper stock fibres in open formation, heating the web to a high degree to transform water therein to steam for opening interstitces between the fibres by the expansion of the steam, creping the web transversely at sharp angles for further opening such portions of the interstices as are adjacent the externally-angled parts of the creped web, and then stretching the web longitudinally to straighten the same to a desired degree for furi ther opening the opposite portions of said interstices. 7

CHARLES W. SMITH.

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