US3528881A

US3528881A - Felt pickup arrangement for paper sheet formed on a papermaking machine wire

Info

Publication number: US3528881A
Application number: US532440A
Authority: US
Inventors: Louis M Stuebe
Original assignee: Beloit Corp
Current assignee: Beloit Corp
Priority date: 1966-03-07
Filing date: 1966-03-07
Publication date: 1970-09-15
Anticipated expiration: 1987-09-15
Also published as: ES338467A1; DE1561645A1; FR1520816A; GB1178861A

Description

Sept. 15, 1970 L. M. STUEBE 3,528,381

FELT PICK-UP ARRANGEMENT FOR PAPER SHEET FORMED ON A PAPERMAKING MACHINE WIRE Filed March 7. .1966 5 Sheets-Sheet 1 INVESTOR.

.' BY' brw l/ z 3 ATTORNEYS Sept. 15, 1970 L M STUEBE 3,528,881

FELT PICK-UP ARRAIiGEMENT FOR PAPER SHEET FORMED ON A PAPERMAKING MACHINE WIRE Filed March 7. 1966 3 Sheets-Sheet 2 l X V EN? 0R. [0m M 570556 A l 2 Z3 44 Sept. 15, 1970 L. M. STUEBE 3,528,881

FELT PICK-UP ARRANGEMENT FOR PAPER SHEET FORMED ON A PAPERMAKING MACHINE WIRE Filed March 7. 1966 5 Sheets-Sheet 3 /44 7mm 75 E RUN LN'VENTOR. ws M 577/655 I Bum Q ATTORNEYS United States Patent 3,528,881 FELT PICKUP ARRANGEMENT FOR PAPER SHEET FORMED ON A PAPERMAKIN G MA- CHINE WIRE Louis M. Stuehe, Beloit, Wis., assiguor to Beloit Corporation, Beloit, Wis., a corporation of Wisconsin Filed Mar. 7, 1966, Ser. No. 532,440 Int. Cl. D21f 2/00 US. Cl. 162306 5 Claims ABSTRACT OF THE DISCLOSURE Pick-up arrangement for Fourdrinier type papermaking machine in which a pick-up slipper maintains the pick-up felt in contact with the take-off run of the wire. The pick-up slipper has a sharp angle of divergence from the wire, which increases the expansion rate of the felt and the velocity of the flow of water back into the felt to wash the sheet into the felt by the expansion of the felt as the felt leaves the wire. A weir is provided beneath the take-off run of the Fourdrinier wire and has a blade contacting the wire under the slipper and transferring moisture from the weir to the wire onto the sheet and effects a uniform flow of water to the backside of the wire adjacent the incoming side of the back flow zone of the felt.

BACKGROUND AND OBJECTS OF INVENTION This invention relates to a felt pick-up arrangement for picking a sheet from a traveling Fourdrinier wire.

In the making of paper, the sheet or web of paper formed on the Fourdrinier wire is transferred from the Fourdrinier wire to the press section of the papermaking machine by a felt pressed into engagement with the sheet and wire by a roll, commonly termed a felt pick-up roll, and changing the direction of the felt to diverge from the Wire with the sheet adhering to the felt. The felt is trained about an upper felt roll downwardly to the pick-up roll to be pressed into engagement with the sheet and wire by the pick-up roll, and as the felt passes about this upper felt roll, the sheet is frequently damaged by the spray from the felt.

Also, as the felt is trained about the felt pick-up roll, the pressure of the roll on the felt and wire, rapidly squeezes water out of the felt into the web or sheet and jams the sheet into the wire by the rapid flow of water from the felt through the sheet as the felt and sheet are squeezed by the wire. This sets the sheet into the wire and makes the subsequent washing of the sheet into the felt more diflicult. As the pressure on the felt decreases as it turns away from the wire, the expansion of the felt will cause a back flow of water from the underside of the wire, which must be of sufficient velocity and volume to tear the base fibers of the sheet loose from the wire. This velocity of back flow is limited by the rate of felt expansion, as it leaves the wire.

The spray coming through the wire as the sheet leaves the wire may also further damage the sheet and it has been found that a sharp angle of divergence between the sheet and wire is desirable to minimize the possibility of this spray damage to the sheet.

The radius of the conventional pick-up roll practical for dynamic balance and deflection, limits the expansion rate of the felt and makes it impractical to take the sheet from the wire fast enough to obviate the foregoing disadvantages, and causes frequent damage to the sheet.

A principal object of the present invention is to remedy the foregoing disadvantages in the transfer of paper from the wire to the press section of a paper making machine by eliminating the conventional felt pick-up roll and replacing it with a slipper or shoe, having a sharp angle of divergence from the wire, and thereby increasing the expansion rate of the felt and the velocity of the flow of water back into the felt by expansion thereof, and reducing the spraying of the sheet as transferred by the flow of water from the wire to the expanding felt and by reducing the drag on the felt by a power fabric moving with the felt between the slipper and felt.

Another object of the present invention is to improve upon the pick-up of a newly formed web or sheet from the Fourdrinier wire by replacing the usual felt pick-up roll with a slipper having a sharp angle of divergence from the wire, and arranged to permit the gradual escape of air that would normally be trapped between the felt and the slipper surface as the felt approaches the surface and thereby avoiding the pocket formed by the approaching felt and the conventional pick-up roll from which trapped air is rapidly expressed through the wet felt, causing a damaging spray on the sheet.

A further object of the invention is to provide a novel and improved felt pick-up structure for a papermaking machine, wherein an endless power fabric is trained under the felt and a slipper engaging the power fabric presses the felt into generally tangential engagement with the wire and diverges from the wire at the outgoing side thereof at a relatively sharp angle to prevent the spraying of the sheet by water from the wire as the sheet leaves the wire and to increase the natural expansion of the felt, to generate movement of the water to efficiently transfer the sheet from the wire.

A still further object of the invention is to improve upon the transfer of a sheet or web from the Fourdrinier wire of a papermaking machine to the press section, by pressing the felt to the wire in generally tangential contact therewith, by a simple and improved form of slipper in which a sharp angle of divergence from the wire at the outgoing side thereof is formed by small diameter roll and in which water is delivered to the underside of the wire through the sheet in uniform amounts across the width of the wire to provide the quantity of water required to efficiently tear the base fibers of the sheet from the wire and pick-up the sheet by the felt at the start of felt expansion.

Another and important object of the invention is to improve upon the transfer of a sheet or web from the Fourdrinier wire of a papermaking machine to the press section, by providing a simple and improved form of slipper, pressing the felt to the wire in general tangential contact therewith, in which a roller at the outgoing side of the slipper, provides a sharp diverging surface from the wire.

These and other objects of the invention will appear from time to time as the following specification proceeds and with reference to the accompanying drawings wherein:

FIG. 1 is a diagrammatic view of a felt pick-up arrangement constructed in accordance with the principles of the present invention;

FIG. 2 is an enlarged view of a form of pick-up slipper that may be used in accordance with the principles of the present invention and showing an adjustable mounting for the slipper;

FIG. 3 is a diagrammatic view illustrating the development of one form of pick-up slipper that may be used in carrying out the principles of the present invention;

FIG. 4 is a graph, graphically showing the water pressures developed as the felt passes under the slipper;

FIG. 5 is a diagrammatic view of the conventional felt pick-up roll illustrating schematically the out-flow and inflow zones as the felt comes into contact with the sheet and wire and picks the sheet from the wire;

FIG. 6 is a graph illustrating the pressures developed with the conventional form of pick-up roll;

FIG. 7 is a diagrammatic view showing a modified form in which the invention may be embodied and showing a roller at the outgoing side of the slipper pressed into engagement with the felt; and

FIG. -8 is a diagrammatic view showing a modified form of slipper, in which the roller is driven by power.

In the embodiment of the invention illustrated in FIGS. 1, 2 and 3 of the drawings, the discharge end portion of a looped Fourdrinier wire 10 is shown as having a newly formed sheet or web W thereon and contacted by an endless pick-up felt 12, picking the sheet from the wire by the back flow of water into the felt, caused by expansion of the felt as the felt changes its direction of travel to diverge from the wire. The wire 10 is shown as being trained downwardly about a roll 13 in an inclined forward discharge run, to and about a roll 15 spaced a substantial distance forward of the roll 13, and about which the wire changes its direction for the return run of the wire.

The pick-up felt 12 may be a conventional form of felt commonly used for pick-up purposes and trained in an endless loop. The felt 12 has a top run 14 which may be uniformly cleaned and moistened, and turns about an idler roll 16, disposed above and shown in FIG. 1 as lapping the wire 10. A conventional form of save-all 17, extends about the idler for the length thereof to collect spray from the felt as the moistened felt turns about the idler 16, and to thereby prevent the spray from damaging the sheet W on the wire 10. From the idler roll 16 the felt passes downwardly in an inclined direction along a power fabric 18, and is pressed to engage and travel with the sheet W and wire 10 by a pick-up means including a slipper 19, engaging the power fabric. The slipper 19 is contoured to provide a relatively soft contact between the felt and wire and to provide a sharp angle of divergence of the felt from the wire, to pick up the web from the felt and to avoid the possibility of damaging the web or sheet by spray from the wire. The slipper 19 and its mounting and contour will hereinafter be more clearly described as this specification proceeds.

The power fabric may be an endless open fabric of a. conventional form and may be power driven to reduce felt drag on the surface of the slipper. As shown in FIG. 1, the power fabric is turned about an upper roll 22 downwardly along the inside of the felt along the contoured surface of the slipper 19. The power fabric may then be trained about a roll 22a and about a series of rolls 22b and 220, any one of which rolls may be power driven to continuously drive the fabric and carry the felt 12 therewith.

A uniform quantity of moisture is supplied to the back side of the discharge run of the wire toward the outgoing end of the slipper 19 by a weir'box 20 supported to extend entirely across the Wire and having a hinged flow plate 21 transversely pivoted thereto, which may be adjusted in any conventional manner to position a Teflon blade 23 extending along the discharge end of the flow plate to supply a uniform quantity of water to the wire as the felt diverges from the wire and picks the web from the wire by the back flow of water through the expanding felt. The region of back flow is at the outgoing end of the slipper where the felt expands as it diverges from the wire and leaves the slipper. This region is commonly termed a back flow zone. An adjustment mechanism 24 is diagrammatically shown in FIG. 1, for adjusting the position of the flow plate 21 and Teflon blade 23 with respect to the wire, to supply the required quantity of water to the wire at the region of divergence of the felt from the wire. The adjusting mechanism for the flow plate 21 and blade 23 may be of any conventional form, so need not herein be shown or described further. While I have herein shown a weir box and flow plate for supplying water to the underside of the wire, the weir box and flow plate need not necessarily be used and a shower of suitable spray pattern and intensity may form an alternate form of water supply means.

FIG. 2 of the drawings diagrammatically shows a form of adjustable mounting for one end of the slipper 19 on a press post 25 for the press section of the machine, it being understood that the slipper is mounted at its opposite end to an opposite press post in a similar manner. Since the mounting for the slipper at each end is the same, the mounting for one end only need herein be shown or described. As shown in FIG. 2, a bracket 26 is suitably mounted on the press post and extends toward the felt 12. A slipper support arm 27 is pivotally mounted on the bracket 26 on a pivot pin 29 at one end and has the slipper 19 pivotally mounted thereon at its opposite end on a pivot pin 30. An adjustment rod 31 is pivotally connected with the upper end of the slipper 19 on a transverse pivot pin 32. The rod 31 slidably extends through a trunnion block 33 trunnioned on the rear upper end portion of the slipper arm 27. A nut 36 may be threaded on the rod 31. The nut may be operated by a suitable ratchet device (not shown) for angularly adjusting the slipper about the pivot pin 30. A gas or fluid positioning device may, if desired, be employed in place of the nut and screw shown.

The slipper is adjustably moved about the axis of the pivot pin 29 by means of a rod 36 transversely pivoted to the central upper end portion of the slipper arm 27 on a pivot pin 37. The rod 36 may be the piston rod of a fluid pressure operated loading or positioning device or may be threaded and supported on a rotatable nut (not shown) for adjustably moving the slipper 19 about the axis of the pivot pin 29. The adjusting means for adjustably moving the slipper 19 and slipper arm 27, and holding said slipper and slipper arm in position may be connected either to the top or the bottom of the slipper arm and may be of any well known form, so need not herein be shown or described further.

By the foregoing adjusting mechanism, the angle of contact of the felt to the web and wire may be adjusted to provide substantially tangential contact and a low velocity of flow from the felt to the wire, and also to provide the required rapid felt divergence from the wire, to effect efiicient transfer of the web or sheet from the wire to the felt, and to avoid damage to the sheet as transferred, by spray from the wire, and by improper flow through the sheet to the felt, as the felt expands in the outgoing or back flow zone of the pick-up.

In FIG. 3 of the drawings I have illustrated the devel opment of a slipper contour which will achieve the flow of water from the felt through the sheet and wire in the quantity desired at the required location and result in a substantially instant termination of pressure, so the felt expansion can take place rapidly and the sheet can be effectively transferred to the felt without damage by spray from the wire.

In the design of the slipper, the unit pressure by a felt or wire pulled around a radius exerted on the radius surface about which the felt or wire is pulled is a function of the tension in the felt or wire and the contour of the surface.

The unit pressure is equal to the tension in the wire or the felt divided by the radius or the mean radius of the contoured surface of the slipper, where T: IN Tension and R=inches radius The wire thus exerts the foregoing unit pressure on the moist felt as the felt and wire wrap the surface of the slipper. This unit pressure causes water to flow from the felt through the sheet and wire to the underside of the Wire in the pickup zone.

In FIG. 3 the contour of the entrant face of the slipper is shown as "being struck from a relatively large radius R which may be a radius of 60 inches for certain felt and wire arrangements, it :being understood that the radius need not be 60 inches but may vary for varying pick-up conditions, varying angles of the discharge run of the wire and the pick-up felt and varying pressure requirements to cause the water to flow from the felt through the sheet and wire to the underside of the wire. R may be preceded by a short straight surface.

The entrant face 40 terminates into a relatively straight surface L which may be in the order of from 2 to 3 inches. The surface L may then terminate into an arcuate surface L formed on a radius R of the same length as the radius R and spaced from the center of the radius R a distance equal to the fiat surface L The axes of, R and R are spaced along said slipper in the direction of travel of the felt. The arcuate surface L is continued by an arcuate surface L the arc of which is struck from a radius of about /3 the length of the radius R and spaced from the radius R toward the outgoing side of the slipper and forms in effect a relatively long radius contact face. The surface L is then continued by a sharply curving surface L formed on a radius R; which may be of the order of 3 inches and provides a rapidly diverging outgoing surface of the slipper.

With the slipper contour just described, the wire exerts a gradual increase in unit pressure on moist felt, as the felt and wire wrap the pick-up slipper 19, with little if any pressure along the straight surface L and gradually increasing in pressure to the sharply diverging surface L as graphically shown in FIG. 4.

This is in contrast to the unit pressure exerted on the felt by the wire, with a conventional pick-up roll having a face formed on a radius of 12 inches, in which the pressure rise and outflow of water from the felt through the wire is instantaneous as soon as the Wire contacts the felt on the radius of the roll, as illustrated in the graph shown in FIG. 6.

With the use of a slipper in place of the conventional felt roll, the wire exerts a gradual increase in unit pressure on a moist felt as the felt and wire wrap the pick-up slipper 19, and causes water to flow from the felt through the sheet and wire to the underside of the wire along the large radius contour of the slipper at its entering or incoming end. This large radius contour together with the gradual decrease in radius toward the outgoing end of the slipper and a sharp increase in radius at the outgoing end of the slipper, permits a flow of water from the felt through the sheet and wire to be achieved at the location desired and in the quantity desired, and gives the control over the flow necessary to achieve a controlled flow from the felt to the underside of the wire with an instant termination of pressure, accommodating rapid expansion of the felt to create the back flow required to efficiently pick up the sheet from the wires.

With the slipper contour and adjustable mounting of the slipper just described, variable settings and various depths of penetrations of water into the wire may be attained, and the operator may have accurate control over the radius at the point of initial contact of the wire with the felt and at the point of final contact of the wire with the felt, and may thereby have control of the final pressure, driving water through the sheet, or washing the sheet onto the felt.

In FIGS. 7 and 8, I have shown arrangements wherein a small diameter roller pressed into engagement with the felt, forms the small diameter radius outgoing side of the slipper.

In the form of the invention illustrated in FIG. 7, the upper rim of the felt 12 is trained over and under a felt roll 41 and downwardly and backwardly of this roll over and under a felt roll 42 and over and along a looped power fabric 43, trained over a top roll 44 about the idler 16 and angularly downwardly and forwardly therefrom under a slipper 19, and about rolls 45, 46 and 47 training the fabric back to the roll 44. Any one of the

rolls

45, 46 and 47 may be power driven rolls to continuously drive the fabric and carry the felt 12 therewith.

A spray 48 is shown as spraying the top run of the felt between the

rolls

44 and 16 while the doctor blade 49 is shown as located on the outgoing side of the spray, to doctor excess moisture from the felt. A save-all 50, like the save-all 17, prevents spraying the sheet on the wire, caused by the turning of the moist felt about the roll 16. Pressure rolls 51 and 52 which may be press rolls of the press section of the paper making machine train the felt and sheet to and along the press section in a conventional manner.

The pick-up slipper 19a, as shown in FIG. 7, has a small diameter roll 43 at the outgoing side thereof. The roll 53 may be a highly polished roll of small diameter, but large enough to not be overstressed by the felt and wire pull, and is shown as forming the small radius outgoing side of the slipper 19a. The radius of the roll 53 may be the same as the radius of the outgoing surface L; of the slipper shown in FIG. 3. A radius of over 3 inches and under 4 inches has been found to be a suitable radius. The roll 53 may be power driven or may be allowed to rotate under sufiicient resistance to prevent the forming of flat spots on the roll. In the form of the invention shown herein, the roll is free to rotate under resistance.

In a modification of the structure, power fabric 43 may be extended beyond the roll 45 and around press roll 51 as shown schematically in FIG. 7 in the dotted line position. By this arrangement the power fabric may be advantageously employed as a water removing device in the press nip defined by rolls 51 and 52.

In the form of the invention illustrated in FIG. '8 a slipper 19b is shown as having a small diameter roll 54 extending thereacross and driven by power. In this arrangement the power fabric is dispensed with, although it may be used where it may be desired to reduce the drag between the slipper and felt. The felt 12 is trained over and under felt rolls 41 and 42, to and around a felt roll 16. A save-all 50 is also provided to prevent spraying the sheet on the wire, as the moist felt turns about the roll 16. The felt 12 passes angularly downwardly and backwardly of the roll 16 and is pressed to engage and travel with the sheet W and wire 10 by the slipper 19b. The felt and web then turn about the roll 54 and pass between pressure rolls 55 and 56 of the press section. Moisture collected from the felt may be collected by a save-all 59 in a conventional manner.

The roll 54, like the roll 53, may be a highly polished small roll, large enough so as not to be overstressed by the felt and wire pull, and may be crowned if required. The radius of the roll 54 is preferably of the order of 3 inches and over. The roll 54 is illustratively shown as being driven in a direction opposite to the direction of travel of the felt, by a motor 60 driving the roll through a belt drive 61. The motor 60 may be a speed reducer type of motor having a speed reducer incorporated as part of the motor shell, and driving the roll at a low enough speed that balance will not be a problem.

A distinct advantage in driving the roll 54 in a direction opposite to the direction of travel of the felt and at a lower linear speed than the speed of travel of the felt, is that the roll will maintain the socket in the pickup slipper in which it is mounted free from felt fibers, and will thereby prevent plugging of the socket and stalling of the roll. The direction of rotation of the roll has been found to be immaterial insofar as to quality of pick-up and power to rotate the roll is concerned, and the advantage of avoiding the plugging of the socket by the felt fibers by driving the roll in a direction opposite to the direction of travel of the felt is a marked advantage in operation of the pick-up.

While I have herein shown and described several forms in which the invention may be embodied, it should be understood that various modifications and variations in the invention may be attained without departing from the spirit and scope of the novel concepts thereof.

3,528,881 7 8 I claim as my invention:

1. A Fourdrinier-type paper making machine comprisof the sheet from the wire onto the felt.

ing: 2. The structure of claim 1, wherein said water supply a Fourdrinier wire having a forward inclined discharge means comprises a weir box extending across and beneath run, the wire, and

wherein the blade is in water-receiving relation with respect to the weir box and extends from the weir box into engagement with the side of the wire opposite the slipper.

,1 3. The structure of claim 2 wherein said blade is made from Teflon.

4. A Fourdrinier-type paper machine in accordance with claim 1,

wherein the contour of said slipper is formed from a plurality of arcs generated by a plurality of radii a looped pick-up felt, means guiding the felt to come into substantial tangential contact with the Wire and sheet thereon and todiverge therefrom at a relatively sharp angle comprising,

an upper felt direction changing roll disposed directly over the inclined discharge run of the wire and changing direction of the felt to travel along said inclined discharge run, a slipper extending for the width of the felt and side of the wire to effect the tearing of the base fibers disposed adjacent said inclined discharge run and contoured to provide a relatively soft contact between the felt and wire, said contoured slipper turnable about axes spaced along said slipper in the direction of travel of the felt therealong and connected together by short straight sections, and

wherein the roll is driven at a lower lineal speed than the speed of travel of the felt. 5. A Fourdrinier-type paper machine in accordance with claim 1,

wherein the contour of said slipper includes a short having a relatively long radius entrant face engaging the felt, an arcuate contact surface forming a continuation of said entrant face and cooperating with said upper felt direction changing roll to press the felt into generally tangential contact with the wire and sheet thereon to gradually transfer water from the felt to the wire, and having a relatively short radius outgoing face rapidly diverging from the wire to define a relatively short back flow zone defined by the area between the outgoing face of the slipper straight entrant surface, and the said entrant face an arcuate contact surfaces are formed by a plurality of arcs connected together by a short straight surface and generated by a plurality of radii of lengths of the order of sixty inches and turnable about axes spaced along said slipper in the direction of travel therealong, and wherein the roll recessed in the slipper at the outgoing end of the slipper and having a peripheral surface and the felt, wherein the felt reexpands and the '30 water drawn through the sheet from the wire by the reexpanding felt washes the sheet onto th f lt, forming a continuation of the arcuate contact surmeans forming said relatively short radius outgoing face face of the slipper is of the order of three inches comprising, in diameter and over and is driven at a lower lineal a relatively small diameter roll recessed in said speed than the speed of travel of the felt.

slipper at the outgoing end thereof and extending for the width thereof and having a peripheral surface forming a continuation of the arcuate References Cited UNITED STATES PATENTS contact surface of said slipper, and 40 3 207 658 9/1965 ,Lamb 162 348 XR means rotatably driving said roll in a direction opposite 2:786:398 3 1 5 s fgzglii: 1 2 30 XR to the direction of travel of the e 3,257,268 6/ 1966 Wrist et al. 162-360 XR and means in the region of contact of the felt with the 2 694 34 11 1954 Goodwinie XR wire and the web, on the side of the Wire opposite 3,441,476 4/1969 Schiel 162306 said slipper, supplying a uniform flow of water to said opposite wire side adjacent the back flow zone including a blade extending across the side of the wire opposite said slipper along the incoming end of the sharply diverging outgoing surface of the slipper and directing a uniform flow of water to said opposite S. LEON BASHORE, Primary Examiner R. H. TUSHIN, Assistant Examiner 0 US. 01. X.R.