US3065789A

US3065789A - Deflectors for fourdrinier forming wires

Info

Publication number: US3065789A
Application number: US841298A
Authority: US
Inventors: Edward D Beachler; Louis E Dennis
Original assignee: Beloit Iron Works Inc
Current assignee: Beloit Iron Works Inc
Priority date: 1959-09-21
Filing date: 1959-09-21
Publication date: 1962-11-27
Anticipated expiration: 1979-11-27

Description

Nov. 27, 1962 E. D. BEACHLER ET AL 3,065,789

DEFLECTORS FOR FOURDRINIER FORMING WIRES Filed Sept. 21. 1959 22 V52? f 571- 5 AL aUG/W Q Baac/er United States Patent 3,065,789 nnrrncrons non ronnnn FORMING winEs The present invention relates to paper machines, and more particularly to an improved drainage control anrangement in a paper machine to provide for a more precise control of the rate of drainage in a Fourdrinier machine.

The table rolls or tube rolls extend transversely beneath the forming wire and are designed to support the wire by forming a level table on which the wire runs after it passes beneath the slice. The rolls are ordinarily supported for free rotation in bearings adjustably attached at the side of the wire in suitable supporting members and are usually rotated by contact with the wire. The table rolls, in addition to supporting the wire, carry 01f water or white water from beneath the surface of the wire. A negative pressure and a pumping effect is experienced at the outgoing nip between the roll and the Wire which is primarily a function of the square of the wire speed. Especially in high speed machines, the water removal function of the rolls is difficult to control in that excessive pumping action may be experienced causing pin holes and loss of fine materials from the web. The table roll carrying water on its surface may likewise damage the formation of the web by the generation of erratic upward forces on the web.

The instant invention resides in a discovery concerning the more effective control of water removal caused by the table rolls and the elimination of undesirable effects on the web on the wire from improper control of water removal.

An object of the invention is to provide an improved table roll combination for the controlled removal of water.

Another object of the instant invention is to provide an improved table roll arrangement wherein controlled drainage will result in a better web and wherein the jump of paper stock on the Wire which causes pin holing and a loss of fines is eliminated.

A further object of the invention is to provide a smooth fully directed flow from a table roll into drainage trays which are also known as savealls.

A still further object of the invention is to provide a table roll arrangement wherein a deflector is mounted in a position to control drainage from a table roll by limiting the pumping action of the high speed roll and is provided with a deflector baflie to provide a drainage channel on the downrunning side of the roll.

Another object of the invention is to provide an improved mechanism for removing water carried around the table roll by providing a non-contacting blade to remove and split the water carried by the roll.

A still further object of the invention is to provide sep arated non-diverging deflectors after a table roll with a deflector baflle to separate the water removed ahead of the first deflector from the water removed between the deflectors.

A still further object of the invention is to provide an improved water removal control mechanism for a table roll which will not have excessive vibrations due to the pulsating effect of the water.

Other objects and advantages will become more apparent with the teaching of the principles of the invention in connection with the disclosure of the preferred embodi- 3,55,789 Patented Nov. 27, 1952 ment thereof in the specification, claims and drawings, in which:

FIGURE 1 is a side elevational view shown in schematic form of the head end of the paper machine;

FIGURE 2 is a top plan view, enlarged from FIGURE 1, showing a series of table rolls, with the Wire removed, and provided with apparatus controlling the removal of water by the rolls;

FIGURE 3 is a vertical sectional view taken substantially along the line IlIlll of FIGURE 4, and,

FIGURE 4 is a vertical sectional view taken longitudinally through a paper machine and illustrating apparatus embodying the principles of the present invention.

As shown on the drawings:

As shown in FIGURE 1, a forming wire 6 carrying a stock S thereon passes over a series of

table rolls

7, 8, 9 and 11 in the direction indicated by the arrow, with the table rolls also shown in FIGURE 2. Following each of the

rolls

7, 8 and 9 are water

drainage control mechanisms

12, 13 and 14, respectively, as will be described in further detail. Beneath the drainage control mechanisms is a drainage collecting tray, also known as a saveall 15. The forming Wire 6 is trained over a closed or plain breast roll 16 and a lower roll 17. Paper stock is supplied to the traveling wire from a head box 18.

As illustrated in FIGURE 2, the table rolls 7, S, 9 and 11 are supported in bearings mounted on longitudinal frame beams 19 and 21 of the Fourdrinier bed. Bearings 22 are shown supporting the ends of the table roll 7, with

bearings

23, 24 and 26 respectively supporting the ends of the

table rolls

8, 9 and ill. Following each of the rolls is a water drainage control mechanism as illustrated at l2, l3 and 14 for the

table rolls

7, 3 and 9.

As shown in greater detail in FIGURE 4, and also as shown in FIGURES l, 2 and 3, each of the water drainage control mechanisms includes a first deflector 27, a second deflector 2.8, a deflector baflle 29, a lower baffle 31, a back bafiie 32., and a blade 33. The function and structure of each of these members in the preferred embodiment will be described in greater detail, and as will be appreciated by those skilled in the art, and function and advantages of individual elements may be utilized in different subcombinations without requiring all of the other elements, although the preferred embodiment contemplates employment of each of the members above recited. inasmuch as each of the water drainage control mechanisms following each of the table rolls are of substantially the same construction, only one need be described in detail and the control mechanism 12, as shown in FIGURE 4 will be described.

An important feature of the invention is the placement of the elements relative to the table roll for obtaining controlled drainage. As illustrated in FIGURE 4, the dimension A which represents the distance from the center 34 of the roll 7 to the leading edge 36 of the first deflector Z7 is critical. At high speeds especially, this dimension A must be sufiiciently large to permit desired drainage and we have discovered that with an inadequate dimension A, the reduction in water capacity at this point i.e., in the throat area 37 between the deflector 27 and roll 7, is a principal source of damaging vibrations of the web 16.

The first deflector 27 has an upper flat surface 27a facing the under surface of the wire 6 and extending at a non-divergent angle with the wire. That is, the surface 27a will not diverge from the Wire in the trailing direction but will be at least parallel to the wire, and may, in some occasions, be inclined to form a converging angle.

The critical nature of dimension A results from the previously mentioned negative pressure present in the area of the outgoing nip 3%; which is an approximate function of the square of the wire speed. With the high speeds s eaves encountered in modern paper machinery very high degrees of suction are created. This removes the water too fast from the web with a consequent loss of fines and fibers. This suction effect also causes the wire to deflect and to wrap the table roll slightly which in turn extends the problem in that the time during which the suction operates tends to cause even further water removal. Under these conditions there is also caused at the table roll a spray of stock which jumps upward from the main stock stream damaging the web both where it leaves the stream and where it falls back onto the web. The causes of this phenomenon are not completely understood. On the other hand efforts to bring wire supporting means into this area, thereby reducing the dimension A below its critical minimum, inhibit water removal. Such constructions also provide insufiicient strength both for the edge of the deflector and for its stiffness as a beam transverse to the Fourdrinier. The pulsating effect of such water as is removed then sets up damaging vibrations in the deflector means. Furthermore, the difficulty of adjusting such deflector means may tend to lift the wire thus tending in turn to stall the rotation of the roll.

If the dimension A is too large or if the deflector 27 is elevated above the plane established by the top surfaces of the table rolls an excessive drag on the stationary surface results. Whether this results from the curvature of the wire span or from the weight of the wire itself the web is also damaged by the disturbance created in the stock.

The actual dimension A depends principally on speed and wire tension, as well as on the character of the stock being formed and the particular position in the sequence of table rolls being used. In a particular paper machine trial settings provide a precise control of the rate of drainage and permit the rapid smooth removal of water without choking or other disturbance in the channel 37.

Because of the action of the table roll- 7, the principal water removal takes place between the roll and the top deflector surface 27a. Drainage to some extent takes place in the channel 39 provided between the first defiector 27 and the second deflector 23. The second deflector 28 has an upper surface 28a which is preferably parallel to the under surface of the wire 6 and forms a non-diverging angle therewith, that is, the upper surface 2811 can form a converging angle or be inclined with respect to the direction of travel of the wire as shown by the arrow.

The drainage through the channel 37 and the drainage through the channel 39 combine below the deflector baffle 29 to be deflected downwardly by the back baflle 32 and to drop down on the lower baffle 31 and flow down into the saveall 15.

The baflie 31 directs the large volume of water removed by the drainage apparatus 12 into the saveall trays 15 with a minimum of disturbance thus permitting the total flow in the tray to move expeditiously toward its outlet. Without such provision the Water falling from the particular deflector might dam up the flow of water in the saveall in turn causing it to overflow onto the return reach of the Fourdrinier wire to damage or destroy it.

A quantity of water will adhere by surface tension to the table roll 7. The blade 33 has a leading edge 33a facing the downrunning side of the table roll and positioned closely to the surface of the table roll but not in engagement therewith. The blade 33 splits the water following the roll and the principal part of the water is diverted to the outer surface 33b of the blade downwardly against the lower baffle 31. An additional amount of water is removed on the inner surface 33c of the blade which to some extent creates a pumping action due to the vacuum created between the blade and the roll 7. This water also flows downwardly against the lower bathe 31 and down into the saveall 15.

The blade 33 reduces to a minimum the water carried by the roll but does so with very little loss of energy as might be the case if the blade were in contact with the roll surface. Since the roll is turned by friction with the wire it is essential that its rotation not be excessively retarded.

The

deflectors

27 and 28, the

baffles

29, 31 and 32, and the blade 33 form lateral beams extending across the machine and are secured at their ends to the longitudinal frame beams of the Fourdrinier bed with provision for precise adjustment of elevation. The back baffle 32 has an angular upper portion 32a which supports the second deflector and together these elements form a laterally extending strengthening beam to be attached at its ends to the longitudinal frame beams 19 and 21. The deflector 27 is also supported at the upper end of the deflector baffle 29, and the baffles and deflectors are secured at their ends to the frame beams 19 and 21.

The water that is removed from the web is withdrawn with a pulsating motion so that the bafiles may vibrate. To aid in strengthening the baffles and enable them to retain their shape and stiffness, a series of transverse gusset plates 42 are provided, as illustrated in FIGURES 2, 3 and 4.

Thus will be seen that we have provided an improved mechanism for controllably removing water from a Fourdrinier wire and a table roll, which meets the objectives and advantages hereinbefore set forth. The mechanism avoids excessive pumping at the table roll, removes the moisture from the surface of the table roll, and achieves an improved moisture removal by control of the moisture removal operation of the roll utilizing deflectors and baflles.

A control of the pumping action of the roll is obtained by the combined deflectors and additional regulation of the roll may be obtained by making the deflector 27 and its deflector baflie 29 adjustable parallel to the direction of movement of the wire in the direction indicated by the arrows 43. This adjustment may be accomplished by mounting the beam formed by the combination of the deflector 27 and deflector balfle 29 on an adjustable mount (not shown) at the end.

The drawings and specification present a detailed disclosure of the preferred embodiments of the invention, and it is to be understood that the invention is not limited to the specific forms disclosed, but covers all modifications, changes and alternative constructions and methods falling within the scope of the principles taught by the invention.

I claim as my invention:

1. In a paper machine, a traveling forming wire for carrying stock thereon, first and second longitudinally spaced table rolls supporting the forming wire, a drainage control device mounted between said rolls and extending for the length thereof and comprising, longitudinally spaced first and second deflectors spaced in the direction of travel of the wire and having top wiping surfaces spaced from said rolls having wiping contact with the wire between said rolls, a vertical drainage duct leading downwardly from said deflectors in the space therebetween and having a back bafiie connected to and leading downwardly from said second deflector along and beneath said second roll, said first deflector having a baflie connected thereto and extending angularly downwardly therefrom into said drainage duct, a blade spaced downwardly from said last mentioned baflie having an edge extending along said first roll, closely adjacent but free from said first roll to split and direct the water on said roll into said duct, said blade with said last mentioned baflle defining a diverging throat opening to said duct, and vertical laterally spaced stiffness plates extending at spaced intervals across said drainage control device between said blade and said back baflle and rigidly attached thereto.

2. In a paper machine, a traveling forming wire for carrying stock thereon, first and second longitudinally spaced table rolls supporting the forming wire, a drainage control device mounted between said rolls and extending ,5 for the length thereof and comprising, longitudinally spaced first and second deflectors spaced in the direction of travel of thewire and having top wiping surfaces spaced from said rolls having wiping contact with the Wire in the space between said rolls, a vertical drainage duct leading downwardly between said deflectors and having a back baffle connected to and leading downwardly from said second deflector along and beneath said second roll, a lower angularly extending baffle inclined to face upwardly toward said back baflfle and to deflect the water removed from the wire in the direction of travel of the wire, said first deflector having a baffle connected thereto and extending angularly downwardly therefrom into said drainage duct, a blade spaced downwardly from said last mentioned bafile having an edge closely adjacent but free from said first roll to split and direct the water on said roll into said duct, said blade with said last mentioned baffle defining a diverging throat opening into said duct and of greater capacity when the volume of water said blade and said baflles to prevent vibration of said blade and said baflles by the action of the water thereon.

References Cited in the file of this patent UNITED STATES PATENTS 1,748,06-2 Cofrin Feb. 25, 1930 1,781,928 Liebeck Nov. 18, 1930 2,170,109 Berry Aug. 22, 1939 2,225,435 Kellett et al. Dec. 17, 1940 2,694,345 Hornbostel Nov. 16, 1954 2,858,746 Goodwillie Nov. 4, 1958 2,893,486 Marti July 7, 1959 2,900,023 Hornbostel Aug. 18, 1959