US2736245A

US2736245A - A mxarn

Info

Publication number: US2736245A
Authority: US
Publication date: 1956-02-28
Anticipated expiration: 1973-02-28

Description

T. A. M ARN METHOD AND APPARATUS FOR MAKING PAPER Feb. 28, 1956 6 Sheets-Sheet 1 Filed June 14, 1952 Feb. 28, 1956 T. A. MQARN 2,736,245

METHOD AND APPARATUS FOR MAKING PAPER Filed June 14, 1952 6 Sheets-Sheet 2 Feb. 28; 1956 MQARN METHOD AND APPARATUS FOR MAKING PAPER 6 Sheets-Sheet 3 Filed June 14, 1952 lN VE N TOR flan 4K6 ,4. M f,

A TTOAIVEYJ' Feb. 28, 1956 T, McARN METHOD AND APPARATUS FOR MAKING PAPER 6 Sheets-Sheet 4 Filed June 14, 1952 INVENTOR view m 1/11 ,404

/ rromvcvs Feb. 28, 1956 T. A. MOARN 2,736,245

METHOD AND APPARATUS FOR MAKING PAPER Filed June 14, 1952 6 She ets-Sheet 5 IN l/E/V T01? T ORA/E VS Feb. 28, 1956 "r. A.-MARN 4 METHOD AND APPARATUS FOR MAKING PAPER Filed June 14, 1952 6 Sheets-Sheet 6 I/V VE/V TOR Wa n-Ire A/ A/ A T TORNE Y5 United States Patent METHOD AND APPARATUS FOR MAKING PAPER Theodore A. McArn, Downingtown, Pa., assignor to Downingtown Manufacturing Company, Downingtown, Pa., a corporation of Pennsylvania Application June 14, 1952, Serial No. 293,620

Claims. (Cl. 92-38) This invention generally relates to that type'of paper making or analogous machinery which employs an endless wire mesh conveying belt or so-called wire, such, for example, as a Fourdrinier paper machine, in connection with which the invention will be described. Such machines are provided, at a suitable point in their length, with a so-called suction box for the removal of water or other liquid from the web of paper stock or other material 0n the moving wire. More particularly the invention relates to the suction box device and the support for the wire.

In a typical Fourdrinier machine, such as illustrated in the drawings, the endless web carrying wire is usually about 142" wide, 90 feet long, and travels at a velocity of from about 400 to about 1000 feet per minute, depending upon the particular end product desired.

The suction device customarily employed in such a machine is in the form of a box having a fiat perforated cover or top extending for the full length and width of the box on which the upper run of the wire is supported and over which it and the web carried thereby move. Suction as high as 16 inches of mercury is ordinarily employed in the box to draw water out of the web and through the wire, with the result that the wire is pressed down onto the top surface of the box with a pressure of 8 lbs. per square inch. Thus, when employing a box with a top supporting surface area of 42 inches by 142 inches, the total down pressure of the wire is approximately 47,700 lbs.

It has been found in actual practice that the resultant friction between the travelling wire and the top surface of the box causes very rapid wear of the wire, to such extent that the effective life of a wire is only about two to three weeks of running of the machine. Also this friction causes wear of the top supporting surface of the box to the extent that the top surface must frequently be ground flat on special grinders at considerable expense, and to do this the machine must be shut down to remove the box or box cover. Shutting down of the machine for this grinding and for replacing of the worn out wire (which is in itself expensive) by a new one results in a very high down time of the machine, with consequent loss in paper tonnage output of the machine. In addition, this sliding friction under such heavy down pressure necessitates high power requirements and limits the speed at which the machine can be effectively operated.

Other known suction devices employ moving belts for supporting the wire, either in the form of a single belt having longitudinally extending slots or holes or a plurality of spaced longitudinally extending parallel belts running across a supporting plate. In such devices the pressure created by the suction causes considerable friction between the belts and their supportingplate with H resultant wear and drag of the belt or belts and consequent high power requirements.

It is further to be noted that in such devices the wire is in continuous contact with the belt or belts in the same area for the full travel across the box, and therefore the web is subjected to suction only at the spaces between the belts or at the openings in the single belt and hence water removal from the web is largely only at these points, with the result that streaks or shadow marks or water marks are caused in the web in those areas over the regions of contact between belt or belts and the wire. In such devices, difiicul'ties are also encountered from the standpoint of uniform belt tension in the absence of which there is uneven wear. Moreover, since the area of effective suction is relatively small, the amount of water removed from the web is reduced, which means that a correspondingly greater amount of water must be removed in the drying operation subsequent to the discharge of the web from the wire. It is considerably more costly to remove moisture by drying than it is by suction. Thus these known types of support entail increased operating expense.

One of the primary objects of the invention is the provision of a suction device having moving means for supporting the wire constructed and arranged in a manner to overcome the foregoing difiiculties. More particularly my invention contemplates substantially increasing the life of the Wire; substantially increasing the interval of time between shut-downs with corresponding increase in tonnage output; a further increase in tonnage output by making it possible to operate the machines at higher speed than customary for the particular type of end product desired; and a substantial decrease in power requirements.

How the foregoing, together with such other objects and advantages as may hereinafter appear or are inci- 1 dent to my invention, is accomplished is illustrated in the accompanying drawings, wherein- Figure 1 is a more or less diagrammatic side elevational view of a Fourdrinier section of a paper manufacturing machine showing a suction device constructed in accordance with my invention in association therewith;

Figure 2 is a plan View on an enlarged scale of the suction device of my invention;

Figure 3 is an end view of the device looking toward the left in Figure l and drawn on a still larger scale;

Figure 4 is an enlarged cross section on the line 4-4 of Figure 1, with portions broken out to condense the figure;

Figure 5 is an enlarged fragmentary cross section taken on the line 5-5 of Figure 3;

Figure 6 is an enlarged fragmentary plan section taken substantially on the line 66 of Figure 3;

Figure 7 is an enlarged fragmentary cross section taken substantially on the line 77 of Figure 6; and

Figure 8 is a cross section taken on the line 8-8 of t Figure 7.

In Figure 1 a high speed conventional type of Four- T drinier section F of a paper manufacturing machine is The Fourdrinier comprises in general supporting structure 9, a head or flow box 10 having a front slice 11 7 under which the pulp flows onto the wire W adjacent the t breast roll 12. The upper run of the wire W passes from,

the breast roll over a plurality of closely spaced table rolls 13, then over the supporting surface of the suction apparatus S, and then over a guide roll 14 to the couch roll 15. The lower run of wire passes from the couch roll over and under a plurality of wire rolls l6 and 17 and then back to the breast roll 12. The

end wire rolls

17, 17 are mounted in adjustable wire tautening devices 18 of well known form.

At the side of the Wire, deckles l9'for preventing flow or leakage of liquid and stock over the sides of the wire are provided. These deckles extend from the slice it located at the stock receiving end of the machine to a point well along the upper run of the wire and are provided with apron cloths 20 as shown in Figures 4 and S.

The formed paperor web P is led from the wire of the Fourdrinier section under a blow roll 21 and from thence to the press section of the machine as is well known in this art.

My improved suction device as shown in Figures 1, 2, 3, 7 and 8, comprises in general a suction or drainage box B, endless ropes or cables R and R, the upper runs of which constitute a moving supporting surface for the wire W, end grooved rolls, sheaves for the ropes, and rope supporting smooth rolls 22.

The uction box B, as will be seen from Figures 3, 7 and b, has a bottom 23,

sides

24, 24,

ends

25, 25, and an open top. Suction conduits 26 lead from the bottom of the box to the sides thereof where they are connected by means of flanges 26a (see Figures 1 and 3) to pipes 26b (see Figure 1) which lead to suction pumps (not shown).

The suction box is supported from the deck rails 27 (see Figures 3 and 4) of the supporting structure 9 of the Fourdrinier as by means of plates 28 (Figure 4). The box is preferably divided into three

compartments

29, 30 and 31 (Figure 3) by means of

baffles

32, 32, the first compartment 29 in the direction of travel of the wire W being substantially larger than the compartments 3t) and 31 for the reason that the amount of water contained in the paper web P decreases as the web passes over the suction box.

The box is braced at the sides by web plates 33, and angle members 34 extend along the upper portions of the sides to provide mounts for the bearing housings 35 of the rope supporting rolls 22 (Figures 3, 4 and 7). Plates 36 are secured to the upper flanges of the angle members 34 on which the side edge portions 37 of the wire W ride. The side walls 24 of the box are provided with semi-circular notches 38 as clearly shown in Figures 7 and 8.

The rolls 22 are mounted at their outer endsin the bearing housings 35 by means of ball bearings 39 and needle bearings 46 as shown in Figure 6. At their inner ends these rolls are mounted by means of antifriction bearings in the housings 41 secured to the longitudinal mounting bar 42 located centrally of the suction box (Figure Referring particularly to Figures 1, 2 and 3, it will be seen that these rolls extend crosswise of the box at the upper portion thereof and are mounted in spaced parallel relation lengthwise of the box to leave substantial suction spaces between the rolls. Thus it may be said that these rolls constitute a roller top for the box providing rolling supporting surfaces for the upper runs of the wire sup} porting ropes or cables R and R and providing suction spaces for free passage of water being removed from the paper web P into the drainage box.

Referring now particularly to Figures 2, 3 and 4, it will be seen that the end grooved rolls for the ropes R and R comprise a pair of aligned drive rolls 43, a pair of aligned tautening rolls 44, a pair of angularly disposed upper rolls 45 located in spaced relation above the lower tautening rolls and a pair of angularly disposed upper rolls 46 located inspaced relation above the lower drive ro1l's43.

One of the drive rolls 43 is provided at its outer end with a drive shaft 47' (see Figure 5), adapted to be connected to a suitable source of driving power and at its inner end with a coupling connection 48 to the inner end of the other drive roll.

These drive rolls are mounted at their outer ends in bearing housings 49 by means of ball bearings 50 and needle bearing 51. The bearing housings are provided with brackets 52 for securing them to support members 53 which are rigidly secured to the suction box as shown in Figure 5. These rolls are mounted at their inner ends in bearing housings 54 by means of needle bearings 55. The housings 54 are secured to the outboard extension of the central supporting plate 42.

The tautening rolls 44 are journalled at their outer ends in arms 56 (Figure 3) pivotally connected to the bottom of the suction box by means of brackets 57 and pivot pins 58. The arms 56 are connected together by a cross brace 59. The cross brace carries a central plate 60 located in the vertical plane of the central plate 42. The inner ends of the rolls 44 are journalled in the central plate 60 and suitable anti-friction bearings are provided in the journals similar to those of the drive rolls.

These tautening rolls are provided for the purpose of taking up slack which may develop in the ropes R and R due for example, to stretching of the ropes. The

arms are connected at their free ends to piston rods 61 of hydraulic piston and cylinder devices of well known form by pin and yoke connections 62. When pressure is applied to move the piston rod downwardly the arms 56 together with the rolls 44 move downwardly to take up the slack and to keep the ropes tight and under tenslon.

The rolls 45 located above the tautening rolls 44 areslightly angularly disposed as-shown in Figure 2, and as viewed in th1s figure it will be seen that they angle in toward the center of the box. At their outer ends these rolls are journalled in bearing housings 63 having brackets 64 (Figure. 3) for securing them to the reinforcing end wall plate 65 of the suction box. At their inner ends the rolls are journalled in bearing housings secured to the outboard extension 66 of the central plate 42. Suitable anti-friction bearings are provided in the journals.

The upper rolls 46 located above the drive rolls 43 areangularly disposed as shown in Figure 2, to be in parallelism with the upper rolls 45'. These rolls are journalled at their outer ends in bearing housings 67 (Figure 3) having brackets 68 for securing them to the reinforcing end wall plate 69 of the suction box. At their inner ends the rolls are journalled in bearing housings secured to the outboard extension 70 of the central plate 42. These rolls are also provided with anti-friction hearings in the manner above described.

It is pointed out that drive is imparted to the ropes R and R by the drive rolls 43 and that the

rolls

44, 45 and 46 run as idlers over which the ropes pass.

By referring to Figure 3 it will be seen that the relative vertical positioning of the grooved end rolls 45 and 46 and the plurality of spaced smooth rope supporting rolls 22 is such that the upper runs 71 of the ropes extend over the top of the suction box to form a moving wire supporting surface, moving at the speed of the wire, and that the drive rolls 43 and tautening rolls 44 are so disposed vertically that the lower runs 72 of the ropes extend under the box as do also the return runs'73 of the ropes. At the upper edges of the two end walls 25 of the box, sealing strips 74 are provided. These strips have semi-circular notches 75 (Figure 8) spaced apart to accommodate the upper runs of the ropes.

The particular arrangement of the ropes R and R will now be described. Referring first to the rope R and starting with the innermost upper run at the central leading end of the box as viewed in Figures 2 and 3, it will be seen that this run leads from the first groove in the upper roll 45 at an angle to the opposite end of the box and then passes over the end roll 46 and downwardly over the lower drive roll 43, then rearwardly under the suction box at an angle to the lower tautening roll, then over the tautening roll and upwardly into the second groove of the upper roll 45, thus forming a first loop of a spiral, so to speak, the pitch of which is determined by the spacing of the roll grooves.

The rope R then leads in the same manner over the rolls again into the next grooves to form a second loop and so on, until the last loop at the left, as viewed in Figure 2, is formed. From this last loop the rope passes over the top roll 45, then over the top roll 46 and downwardly over a vertically disposed sheave 76, then over a horizontally disposed sheave 77 and from thence in the return run 73 at an angle inwardly over a horizontally disposed sheave 78, then upwardly over a vertically disposed sheave 79 to the point of starting.

The two ends of the rope are spliced together to form an endless rope, and it will be seen from the foregoing that the rope as thus laid forms a spiral composed of a plurality of loops, the upper runs of which are disposed at a slight angle to the direction of travel of the wire W (preferably an angle whose tangent is .04).

Thus a given point on the upper runs of the rope in travelling from the leading end to the other end of the suction box moves laterally a distance determined by the pitch or angle of the spiral. However, since the wire travels in a straight line and since the points of contact between the wire and runs continually shift slightly laterally during travel of the runs and wire over the box, it is to be observed that the entire area of the wire W and the web P will be exposed to suction or differential pressure before it leaves the box, thus ensuring uniform water removal over the entire surface of the web. Stated in another way, the continual shifting or constant changing of the contact points between the runs of rope and the wire ensure that 100% of the paper web will be exposed to the diiferential pressure which removes the liquid throughout the web, and streaking or shadow or water marking of the web is prevented. Because of the slight angling or askewing of the supporting ropes, the friction between ropes and wire is reduced to negligibility.

It is also to be observed that this roller top and rope support arrangement greatly increases the suction area over existing apparatus and in fact provides 100% of suction area except for the small area of the ropes.

The rope or cable R is similarly arranged in spiral fashion, but it is to be noted that the upper runs of the loop angle away from the upper runs of the loops of the rope R. This is clearly shown in Figure 2, from which it will be seen that the upper runs of rope R slightly angle to the left in the direction of travel while the upper runs of the rope R slightly angle to the right.

This opposed slightly angular relation causes the rope runs to exert a lateral spreading or flattening influence on the wire, thus preventing what is known as center bunching of the wire. This prevents damage to the wire and further increases its life.

Since the ropes are continuous, all of the loops are under the same tension while running, so that a uniform and firm supporting surface is provided.

While in the form of my invention above described two endless wire supporting ropes are employed, I also contemplate employing a multiplicity of endless ropes disposed angularly and supported as above described to obtain the advantages set forth.

Although I have described the diflferential pressure as being obtained by suction, this differential pressure may be obtained in other ways, as, for example, by providing a pressure of one or more atmospheres on the top of the web and having the drainage box open below.

It will be seen from the foregoing that I have provided a moving supporting surface for the wire which eliminates heavy sliding friction and drag such as would exist in having the wire ride on a fixed flat surface. The elimination of this heavy friction greatly reduces the power requirements for drive. Also in providing rolling surfaces on which the ropes or cables are supported, wear of the ropes is kept at a minimum and power requirements are kept down.

The provision of the large unobstructed suction area above referred to greatly aids in removing water from the web,'this being advantageous in that the more water that is removed by the suction device the less expensive and time consuming the subsequent drying operation will be.

Furthermore, because of the elimination of the heavy friction and the more effective removal of water from the web afforded by my invention, the machine can be operated at much higher speeds than heretofore possible, with the result that the output of the machine is greatly increased.

The life of the wire is increased very substantially indeed; and since shut-downs to overhaul may be made only when a wire must be replaced, it will be seen that the length of the intervals between shut-downs is materially increased, with a corresponding increase in tonnage output, i. e., earning capacity of the machine.

While I have described and claimed the invention in connection with paper making machines, it will be understood that the invention is applicable to analogous equipment and operations.

I claim:

1. In a paper making machine having a pulp receiving and conveying endless wire and a suction box over which the wire passes for removing liquid from the web of pulp stock carried by the wire: a moving support for the wire in its traverse over the suction box, comprising a plurality of elongated moving supporting elements, each engaging and supporting the wire in a zone extending along the wire in the general direction of travel of the wire, and means for moving each of said elements in a path lying in a plane parallel to the plane of the wire but angularly offset, in said plane, from the longitudinal axis of the wire.

2. In a paper making machine having a pulp receiving and conveying endless wire, and a suction box over which the wire passes for removing liquid from the web of pulp stock carried by the wire: a support for the wire in its traverse over the suction box, comprising a plurality of laterally spaced runs of rope lying in a plane parallel to the plane of the wire, but angularly offset, in said plane, from the longitudinal axis of the wire, and means mounting said runs for movement along their axes.

3. A construction in accordance with claim 2 in which the support is in the form of an endless rope spirally arranged.

4. A construction in accordance with claim 2 in which the support is in the form of a plurality of endless ropes spirally arranged.

5. A construction in accordance with claim 2 in which the support is in the form of a pair of endless ropes spirally arranged, with the runs of one rope slightly inclined in one direction of the line of movement of the wire and the runs of the other rope slightly inclined in an opposite direction.

6. A construction in accordance with claim 3 in which a tautening device is provided to take up slack in the support.

7. A construction in accordance with claim 3 in which rotatable grooved rolls are provided for the rope runs.

8. A construction in accordance with claim 7 in which the grooved rolls are longitudinally spaced with respect to the box and further characterized by that a plurality of transversely extending idler rolls are interposed between the grooved rolls for supporting the runs of the rope.

9. A construction in accordance with claim 7 in which the grooved rolls are slightly inclined with respect to a line at right angles to the line of movement of the wire plo 7 and at an angle substantially the same as the angle of inclination of the runs of the'rope.

10. A construction in accordance with claim 3 in which sheaves are provided to direct'the rope from'the end to the start of the spiral.

References Cited in the file of this patent UNITED STATES PATENTS 1,236,006 Plumb et al Aug. 7, 1917 10 8 Argy, Dec. 15, 1931 Hadley May 24, 1932 Catala et a1. Sept. 6, 1932 Johnson eta1; Dec. 19, 1933 Tomkins Mar. 20, 1934 Nash Jan. 20, 1942