US1880057A - Method of and machine for making paper - Google Patents

Description

Sept. 27, 1932. J. c. SHERMAN METHOD OF AND MACHINE FOR MAKING PAPER Filed June 20, 1931 Patented Sept. 27, 1932 UNITED sTATEs JOHN CPSHEBM AN, OF GORHAM, MAINE, A SSIGNOR TO BROWN COMPANY, OF BERLIN,

PATENT OFFICE NEW HAMPSHIRE, A CORPORATION OF MAINE METHOD OF AND MACHINE FOR, MAKING PAI'ER Application filed June 20,

This invention relates to a method of and machine for making paper, its object being to produce paper having more nearly uniform physical characteristics, especially tear resistance and folding endurance, than those found in ordinary papers.

One of the major defects likely to exist in paper as ordinarily produced is that the web of paper taken off the paper machine invariably possesses different physical characteristics in its lengthwise and crosswise directions. This is trueof papersproduced on either a. cylinder or Fourdrinier type of paper machine, as in the case of papers produced on both these types of machines there is usually lackof suflicient cross-lying fibers to make for the desired uniform texture. while in the case of a cylinder-machine-made paper this condition may sometimes be so serious that splits or tears are easily produced lengthwise of the paper web, nevertheless it obtains also in Fourdrinier-machinemade papers, despite the fact that the Fourdrinier machine may include mechanism for shaking the forming wire or its other parts in orderto offset the pronounced tendency for the fibers to assume a longitudinal lay, i. e., in the machine-direction. When one considers the conditions under which paper is formed even ona Fourdriniermachine, it is not surprising that the fibers tend to assume a preponderantly longitudinal lay.

Thus, it is usually the practice to flow the pulp suspension onto the forming wire at a rate of speed substantially equal to that of the forming wire, so that when-the pulp suspension reaches the wire, the fibers have a longitudinal component of motion with comparatively little lateral component of motion, especially at high papermaking speeds. The effect of a lateral component of motion imparted by shaking means after the suspension is already on the Wire is in practice usually insufiicient to offset the decided tend ency for the fibers to arrange themselves lengthwise on the wire and to retain this arrangement.

In accordance with my invention, I impart to the flowing stream of pulp suspension, preferably just before it is deposited 1931. Serial no. 545,711.

onthe traveling forming wire or equivalent instrumentahty, a lateral or so-called acrossdirection component of motion a-pproximating that of. the so-called machine-direction deposited on the forming wire or equivalent 'lnstrumentality immediately above a suction box or analogous dewatering device, whereby the suspension is reduced as quickly as possible to a .quasi-dough-like consistency, so as to inhibit the tendency for the fibers to undergo rearrangement in their further course on the paper machine. In other words, the W fibers are preferably largely fixed in their prearranged state immediately upon contacting with the web-forminginstrumentality. While it is possible togive the flowing stream of pulp suspension a lateral component of motion in various ways, I prefer to do this by causing a belt or its equivalent to move directly under the stream in a direction substantially perpendicular. to the direction of flow immediately before the stream reaches the web-forming instrumentality. The belt is preferably of a width or girth to make considerable area of contact with the stream, its contacting area, speed of travel, kind of surface, etc., being coordinated with the speed of the papermaking machine, so as to throw a sufficient proportion of the fibers in the across-direction. The belt can be made of thin, flexible sheet metal, rubber, or other preferably water-impermeable material, and canbe suitably roughened or grooved'transversely of its direction oftravel to promote .imparta-tion to the stream of the desired predetermined lateral component of motion. .lViththe foregoing and other features and objects in view, I shall now describe in great er detail the application of the principles of my invention. While not limited thereto,

a Fourdrinier type of paper machine has been Chosen for purposes of illustration on the accompanying drawing, wherein p Figure 1 is a plan view of the wet end of the machine equipped with a cross-feed for thesstream of pulp suspension immediately adjacent to the pulp-depositing station.

Figure 2 represents a longitudinal section through the wet end.

Figure 3 illustrates conventionally and diagrammatically the use of opposite cross-feeds at the wet end of a machine having a pair of separate pulp-depositing stations.

Referring first to Figures 1 and 2 of the drawing in detail, 1 represents the traveling wire cloth of the machine, which, as best shown in Figure 2, passes successively over a breast-r0112, a series of table-rolls 3, a suction box 4, and some, more table-rolls 5. Between the last of the series of rolls 3 and the suction box 4 is shown a cross-feed belt 6, the

front edge-of which terminates directly over the box. The belt may be mounted upon a pair of terminal pulleys 7, one or both of which may be driven by suitable means (not shown) so as to propel the belt-crosswise of the direction of travel of the wireas indicated by arrow. The pulleys are somewhat spaced from the, side edges of the wire and can be arranged, as shown, at an elevation to cause the .belt to clear the wire with as little a gap or clearance as possible. It is the belt 6' which serves as the means for imparting a lateral component of motion to the continuous stream. of pulp flowing onto the wire,

for the belt moves directly in contact with the stream and at right angles thereto immediately before the stream reaches the wire. In fact, the stream is actually directed over the front portion of the belt, whence, it runs over the forward edge of the belt onto the wire portion directly over the suction box 4. Substantially no splashing. or eddyingsuch as would impair the quality of the resulting paper should take place as the pulp suspension-meets the forming wire.' This can be ensured against by having the stream meet the wire at the proper machine-direction rate of flow, and by having the minimum cascading of the stream from the belt onto the wire. So, too, the applicationof suction onto the pulp suspension as soon as it contacts with the wire tends to quell any material turbulence ,pension on account of its bein invention, therefore, makes possible the shortening of the wet end of the paper machine and an elimination of the shaking mechanism and its wear and tear on the machine.

The continuous stream of pulp suspension for the machine may be supplied from a flowbox 8 stationed in back of the breast-roll 2. The flow-box may continuously receive excess pulp suspension of the desired consistency,say to fiber content, from. a pipe 9 leading from the stock regulator (not \shown) The pulp suspension issues through a horizontal slot-or so-called slice 10 in the front wall of the box, and flows over a slightly inclined sluice or channel 11, which directs the suspension over the front portion of the belt 6, as already described. The size of the slot 10 may be varied by a vertically adjustable gate'12 to govern the rate of discharge of the pulp suspension from the box. The excess pulp suspension in the box overflows the rear wall 13finto a rear compartment 14, from which the suspension gravitates through a pipe 16 to a storage tank or save-all (not shown) for reuse. The head of pulp suspension in the box and, accordingly,'the rate of discharge from the box, may be determined by constructing thetop portion of the rear wall 13 as a vertically adjustable dam 15.

Because the belt 6 tends to carry the stream of pulp suspension beyond the edge of the wire intersected by the diagonal resultant of stream motion, the sluice is shown as being of considerably less width than the wire, and located midway between its edges, so that no matter how the belt'is run, i. e., as indicated by arrow or in the opposite direction, there is sufiicient width of wire on which the stream may be deposited and retained as it leaves the belt. If the belt is intended for running in only one direction, the sluice 15 may be of the same width as the wire, but its longitudinal center line should be offset sufliciently from the longitudinal center line of the Wire toward that edge of the wire not intersected by the diagonal resultantof stream motion so that there is little or no loss of pulp susdischarged from the belt beyond the edge 6 the wire intersected by the diagonal resultant of stream motion. The tendency of discharging the pulp suspension beyond an edge of the wire is greatly reduced by the dewatering action which the pulp undergoes immediately, upon striking the wire.

In Figure 3, the wire 20 is shown passing under a suction box 21. and then under a sec ond suction box 22 spaced a substantial distance from the first suction box. Associated with the suction box 21 is a cross-feed belt 23, and with the suction box 22 a cross-feed belt 24, the belts moving in opposite cross directions, as indicated by" arrow. Each belt has a'sluice 25 and a flow-box 26 for the purpose hereinbefore described, the fibers being deposited on the wire first as a layer or web whose fibers have an effective diagonal lay in one direction and then as a superposed layer or web whose fibers have an effective diagonal lay at right angles to the first diagonal lay. In other words, each lay may be at to the machine-direction, but at 90 to each other. hen such a paper is subjected to tearing, it tends to produce a straight line of tear, whereas, on the otherhand, in a paper all of whose fibers have an effective diagonal lay in only one direction, as previously described, the line of tear tends to drift toward this one direction of fiber lay.

The use of belts or their equivalent to impart a lateral component of motion to a stream of pulp suspension flowing continuously to and in the direction of movement of a moving web-forming instrumentality is broa dly my invention, whether the web-forming instrumentality takes the form of an endless wire cloth, such as used in a, Fourdrinier machine, or whether it takes the form of a wire-cloth-covered roll or cylinder mould, such as used in a cylinder machine. This component of motion imparted to the stream may be of such magnitude and in such a direction as to produce on the web-forming instrumentality a web in which the effective lay of the pulp fibers is approximately 45 to the direction of movement of said web-forming instrumentality.

What I claim is:

1.. In a method of mziking paper involving the delivery of a continuous stream of pulp suspension to and in the direction of movement of a progressively moving web-forming instrumentality, that step which comprises continuously imparting to the stream immediately before it reaches said instrumentality a component of motion substantially perpendicular to the direction of motion of said instrumentality. v

2. In a method of making paper involving the delivery of a continuous stream of pulp suspension to and in the direction of movement of a progressively moving web-forming instrumentality, that step which, comprises continuously imparting to the stream before it reaches said instrumentality a component of motion substantially perpendicular to the direction of motion of said instrumentality, said component of motion being of such a magnitude as to produce a web in which the effective lay of the pulp fibers is approximate- 1y 45 to the direction of motion of said instrumentality.

3. In a method of making paper involving the delivery of a continuous stream of pulp suspension to and in the direction of move mentof a progressively moving web-forming.

instrumentality, that step which comprises continuously imparting to the stream imme diately before it reaches said instrumentality a component of motion of such magnitude tality.

and in such a direction as to produce a web on said instrumentality in which the effective lay of the pulp fibers is approximately 45 to the direction of motion of said instrumentality.

4* In a method of making paper involving the delivery of a continuous stream ofpulp suspension to and in the direction of movement of a progressively moving web-forming instrumentality, those steps which comprise continuously imparting to the stream immediately before it reaches said instrumentality, a component of' motion of such a magnitude and in such'a direction as to produce a web on said instrumentality-in which the effective lay of the pulp fibers is approximately 45 to theidirection of motion of said instrumentality, and partially dewatering said pulp immediately as it reaches said web-forming instrumentality.

5. The combination with amoving webforming instrumentality and means for delivering a continuous stream of pulp suspension to and in the direction of movement of said instrumentality, of means for continuously imparting to said stream immediately before it reaches said instrumentality a component of motion of a magnitude and in a direction to cause the pulp fibers to assume an effective lay on said instrumentality of approximately 45 tothe'directiOn of motion of said instrumentality.

6. The combination with a moving webforming instrumentality and means for delivering a continuous stream of pulp sus pension to and in the direction of movement of said instrumentality, of means for continuously imparting to said stream immediately before it reaches said instrumentality a component of motion of a magnitude and in a direction to cause the pulp fibers to assume an effective lay on said instrumentality of approximately 45" to the direction of motion of said instrumentality, and meansfor dewatering the pulp as soon as itreaches said instrumentality. 1 v

7 The combination with a moving Webforming instrumentality and means for delivering acontinuous stream of pulp suspension to and in the direction of movement of said instrumentality, of a belt passing directly under the stream immediately before it reaches the web-forming instrumentality and moving substantially at right angles to the direction of movement of said instrumen- 8. The combination with the endless moving wire of a Fourdrinier machine and means for delivering a continuous stream of pulp suspension to and in the direction of movement of said wire, of a belt moving across said wire directly under said stream immediately before said stream reaches said wire.

'9. The combination with the endless moving wire of a Eourdriniermachine and means for delivering a continuous stream of pulp suspension toand in the direction of movement of said wire, of a belt moving across a said wire directly under said stream immedi- 5 ately before-said stream reaches said wire, and means for dewatering said pulp as soon as it contacts with said instrumentality.

10. The combination with the endless mov-. ing wire of aFourdrinier machine and means for delivering two continuous streams of pulp suspensionto and in the direction of movement of said wire but at spaced intervals thereon, of a belt for each of said streams moving across said wire and directly under said '5 streams in opposite directions immediately before said streams reach the wire. i

In testimony whereof I have afiixed my a signature. JOHN C. SHERMAN.

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