US3483080A - Paper forming support roll with stationary shaft and rotatable tube thereon - Google Patents

Description

W. C; NOTBOHM PAPER FORMING SUPPORT ROLL WITH STATIONARY Dec. 9, 1969 SHAFT AND ROTATABLE TUBE THEREON 2 Sheets-Sheet 1 Filed Feb. 15, 1966 INVENTOR. 4

WILLARD C. NOTBOHM ATTORNEYS Dec. 9, 1969 w. c. NOT HM 3,483,080

PAPER FORMING SUPPORT R WITH ST ONARY SHAFT AND ROTATABLE TUBE THER .1

Filed Feb. 16, 1966 2 Sheets-Sheet? FIG 5 72 7| r 72 Q I Q \X\ o so"- Isl FIG 6 5 70 w 62 8| so 82 e2 C) 0 0C) 00 O 0 0 so 9o United States Patent 3,483,080 PAPER FORMING SUPPORT ROLL WITH STA- TIONARY SHAFT AND ROTATABLE TUBE THEREON Willard C. Notbohm, Watertown, N.Y., assignor to The Black Clawson Company, Hamilton, Ohio, a corporation of Ohio Filed Feb. 16, 1966, Ser. No. 527,865 Int. Cl. D21f 1/26 U.S. Cl. 162-354 9 Claims ABSTRACT OF THE DISCLOSURE This invention relates to paper machinery, and more particularly to rolls for use in supporting a paper machine forming wire or the like.

The invention has special relation to table rolls, namely the rolls which are used in multiples to support the forming wire of a Fourdrinier paper machine during the initial portion of its travel from the headbox to the couch roll. It is desirable that these rolls 'be of sufliciently small diameter so that their uppermost surface portions are relatively closely spaced for proper support of the wire, but it will be apparent that the smaller the diameter of roll for a given wire speed, the greater will be its rotational speed and resulting load on its bearings. In addition, rolls of this type have critical rotational speeds, depending upon their diameters, at which they tend to vibrate to such extent as to have undesirable effects on the sheet formation. This in turn has lead to the practice of increasing the diameter of the table rolls, particularly for wide and high speed machines, in such ratio to their lengths that the length of each roll should be not more than about 18 times its diameter.

Another factor affecting the design of table rolls is that in addition to supporting the forming wire, they perform the function of applying a pumping force to the sheet as it forms on the wire, by reason of the vacuum developed where the surfaces of the wire and each roll diverge in the direction of wire travel. It is important for uniform sheet formation that this pumping action be uniform across the sheet at each table roll, but this result is diflicult to achieve because of the normal tendency which is accentuated and harder to combat in the case of relatively long rolls of small diameter.

It is accordingly a primary object of the present invention to provide table rolls of such novel construction that they can be made of substantially smaller diameter with respect to their axial length than has heretofore been thought possible while avoiding complications of both critical speed and deflection.

Another object of the invention is to provide a table roll having the advantages outlined above which is of such novel construction that it eliminates bearing problems of previous table rolls and at the same time is relatively easily trussed or prestressed to compensate for normal deflection.

An additional object of the invention is to provide a table roll as outlined above which comprises an outer "ice tube rotata'bly supported on a stationary shaft by means of an internal film of lubricating fluid, such particularly as water, without the necessity of conventional bearings.

A still further object of the invention is to provide a table roll constructed as outlined in the preceding paragraph wherein the stationary shaft is equipped with means for trussing or prestressing it to compensate for normal deflection in order to support the rotatable tube in essentially straight condition parallel with the forming wire supported thereon.

It is also an object of the invention to provide a suction box for a paper machine which is equipped with an active surface comprising multiple small rolls each individually of essentially the same construction as the table rolls of the invention.

Still other objects and advantages of the invention will be apparent from the following description, the accompanying drawings and the appended claims.

In the drawings FIG. 1 is a fragmentary view, partly in axial section, showing a table roll constructed in accordance with the invention and mounted on a Fourdrinier paper machine;

FIG. 2 is a section on the line 22 of FIG. 1;

FIG. 3 is an enlarged section on the line 3-3 of FIG. 1;

FIG. 4 is a view similar to FIG. 2 showing an alternate construction for mounting and prestressing the table rolls of the invention;

FIG. 5 is a somewhat diagrammatic View generally in section on the line 55 of FIG. 6, showing a suction box constructed in accordance with the invention;

FIG. 6 is a fragmentary section on the line 6-6 of FIG. 5;

FIG. 7 is a somewhat diagrammatic side view showing anothe rform of suction box in accordance with the invention in combination with a traveling belt; and

FIG. 8 is a fragmentary view of the belt used with the suction box of FIG. 7.

Referring to the drawings, which illustrate preferred embodiments of the invention, FIGS. 1-2 show a table roll 10 constructed in accordance with the invention and mounted on the sider ails 11 of a Fourdrinier paper machine in supporting relation with the forming wire W. The roll 10 is positioned transversely of the path of the wire and includes a stationary central shaft 13 which may advantageously comprise a pipe as shown, provided with an end head 15 at each end, and it is desirable that these parts be made of stainless steel or other corrosion resistant material.

Mounted on the stationary shaft 13 is a rotatable tube 20 which may be made of metal or plastic, satisfactory results having been obtained with such tubes formed of a plastic of high strength and good bearing qualities such as nylon or epoxy. The tube 20 should have an inner diameter sufiiciently greater than the outer diameter of the shaft 13 to provide a small annular clearance 22 therebetween, and satisfactory results have been obtained with this clearance having a radial dimension in the range of approximately .0l5.030 inch.

Provision is made in accordance with the invention for supplying the space 22 with fluid under sufficient pressure to maintain the space 22 full of such fluid, which may conveniently be water, although oil or gas could be used. A fluid supply tube 25 is shown as extending through the end head 15 to an outlet port 26 (FIGS. 1 and 3) located within the top portion of the wall of the shaft 13 which is preferably equidistant the ends of the shaft and at the mid-point of the paper machine. In operation, the inlet end 27 of the tube 25 is connected to a suitable source of supply pressure so that the space 22 is maintained full of fluid while there is a continual leak of such fluid from both ends of the space 22.

It is desirable to limit axial movement of the tube on shaft 13 so that it stays substantially centered with respect to the paper machine, and also to provide some restriction to free fluid discharge from the ends of the space 22 in order to minimize the amount of fluid supplied thereto. Both of these objectives are accomplished in accordance with the invention by means of stop means or collars mounted on the shaft 13 in spaced relation slightly further apart than the overall length of the tube 30 to provide a running axial clearance therefor, which may total, for example, .125 inch. This result is readily obtained by making the collars axially adjustable on the shaft 13 with the aid of set screws 31. In addition, each collar is shown as provided with an arcuate shroud 33 which encloses the top and side portions of the junction of the collar with the tube 20, to prevent radial spraying of fluid from the ends of the space 22.

It is not necessary to maintain high pressure on the fluid supplied to the space 22, particularly when using water or other liquid for lubrication, and pressures as low as 1 to L2 p.s.i. have proved adequate. It is only necessary that the supply pressure be sufficiently high to maintain the space 22 full of fluid, and this result is aided by the restrictions provided by the collars 30, which not only throttle the discharge flows of liquid but also balance these flows sufficiently to keep the tube 20 substantially centered between and out of contact with the collars 30.

The end portions of the shaft 13 which project beyond the tube 20 are provided with stationary mountings on the rails 11 which may take a variety of forms as now described. FIGS. 1-2 show the end of the shaft 13 supported by a pivot means or through pin 35 carried at its ends by a support member or yoke which is in turn rotated on a rotating means or pin 41 carried by a fork portion of a base piece 42 mounted directly on the adjacent rail 11. The design of the base 42 can vary widely depending upon the shape of a specific rail 11, and it is shown as having a T-portion 43 slidable in a track within the rail 11 and held in adjusted position by clamp bolts 44. The yoke 40 is adjustable vertically on the pin 41 to locate the uppermost portion of the tube 20 at the proper level, by means of a stud 45 depending from yoke 40 into a recess 46 in base 42 and provided with an adjustable nut 47 adapted to seat on the base 42.

Provision is made in accordance with the invention for trussing or prestressing the shaft 13 to compensate for its normal downward deflection. As shown in FIGS. 1-3, a tension rod 50 extends through the lower portion of the shaft 13 below the pins 35 and is threaded on one or both of its ends to receive an adjustable nut 51 and thrust washer 52. Tightening of the nut 51 will cause the midportion of the shaft 13 to pivot upwardly about the pins 35 to compensate or correct for its normal downward deflection, and in this manner the shaft 13 can be substantially straightened to align the tube 20 in accurate parallelism with the wire W.

As already noted, when the table roll 10 is in operation on a paper machine, it will rotate at relatively high speed on an annulus of either water or other fluid contained within the space 22. Experiments indicate that the performance of such a table roll improves as its rotational speed increases, since the tube tends to assume as perfect a condition of concentricity as possible on the shaft 13. Thus the tube 20 is supported in operation entirely out of contact with the shaft 13 for minimum friction without the necessity of conventional bearings.

An important advantage achieved by the invention is the elimination of problems of critical speeds such as have been encountered with table rolls of conventional construction, even though the table rolls are made of notably smaller diameters than in conventional practice. Thus on a machine built to carry a wire 300 inches wide, conventional practice would call for table rolls of the order of 18 inches in diameter, namely about /1g of the roll length. In contrast, satisfactory results are achieved in the practice of the invention on a 300-inch paper machine with each shaft 13 constructed of stainless steel pipe of a nominal diameter of 6 inches and with each tube 20 approximately inch thick and 6.625 inches in outer diameter. Furthermore, far from being subject to problems of critical speed, such rolls do not exhibit tendencies to objectionable vibration at speeds which would be critical for a solid roll of the same length and diameter but in fact run increasingly more quietly at speeds which would otherwise be in the critical range. It appears that this result may be at least in part due to the damping effect of the supporting annulus of water between each rotating tube and its stationary supporting shaft.

FIG. 4 shows an alternate arrangement in accordance with the invention for stressing a table roll 20' to compensate for deflection. The shaft 13 in FIG. 4 corresponds to the shaft 13 but is shown as solid and provided with an internal passage 25 corresponding with the tube 25 and terminating in a similar outlet port 26'. The shaft 13 includes an outer end extension 13 projecting beyond the rail 11, this construction being duplicated at both sides of the machine. Means are provided for urging these end extensions 13" downwardly about the associated pin 35', and such means are shown diagrammatically as a turn-buckle 55 connected between the extensions 13" and a bracket 56 projecting laterally from the rail 11'. It will be apparent that either mechanical or hydraulic means can be used to perform the function represented by the turn-buckle 55, to cause the mid portion of the shaft 13' to be cambered upwardly into the desired condition of straightness. Otherwise the roll 20 is the full equivalent of roll 10, and its other similar parts are identified as 30', etc.

The rolls of the invention are adapted for uses other than as table rolls, such particularly as to form a live surface for a suction box. Thus referring to FIGS. 5-6, the suction box 60 has side and end walls 61 and 62 defining a rectangular chamber having a suction connection 65 through its bottom wall 66. A wear strip 70 extends inwardly a short distance from the top of each side wall 61 to support the deckle edge of the wire W, and another Wear strip 71 extends inwardly a short distance from the top of each end wall 62. A load carrying roll 72 of substantial diameter may be mounted as shown closely adjacent the inner edge of each of the wear strips 71 to decrease the friction of the wire thereon.

The major portion of the top surface of the suction box '60 is formed by a multiplicity of small diameter rolls 75, each of which may be substantially identical in construction with the table roll 10, particularly on relatively narrow paper machines, and each of which has an internal fluid supply corresponding to the tube 25. On wider machines, wherein the tendency of small rolls to downward deflection is more pronounced, it is preferred to use at least two tubes on each shaft 81 and to support each shaft 81 by one or more braces 82 mounted on the bottom wall 66 and engaging the shafts 81 at the locations between the tubes 80 thereon. In order to minimize any tendency to marking of the paper as the result of gaps between tubes 80 on the same roll, two or more braces 82 may be used in laterally spaced relation across the suction box 60 as shown in FIG. 6, with the tubes 80 similarly of different lengths so that the gaps between tubes on adjacent shafts 81 are offset laterally with respect to each other. The differentially scalloped upper edge of the braces 82 as shown in FIG. 5 will accomplish this purpose, and individual or other arrangement of braces could be used to accomplish the same result.

FIGS. 78 illustrate the application of the invention to a suction box of the traveling belt type such as shown in Evans Patent 2,039,308 of 1936. The suction box 85 is provided with a suction connection 86, and its upper surface is formed by multiple rolls 88 each of which may be individually substantially identical in construction with the roll 10 or the rolls 75 of FIGS. 5 and 6. A large roll 90 is located immediately adjacent each end of the suction box 85, and the rolls 90 cooperate with a guide roll 91 to support a perforated continuous belt 95 for travel across the rolls 88 in supporting relation with the forming wire W.

Since the construction of FIG. 7 substantially eliminates friction between the belt 95 and the suction box, it is possible to employ a belt 95 having substantially greater open areas than in previous suction boxes of this type, as well as a belt constructed of materials other than the rubber belts which have conventionally been used. Thus the belt 95 may be made of a material such as laminated kraft paper having multiple circular holes 99 punched therein as shown in FIG. 8, arranged in such pattern as to provide upwards of 30% open area. Such belts can be produced so much less expensively than rubber belts as to be economically expendable, can readily be made even stronger than rubber belts, and will produce less tendency to marking of the sheet than rubber belts.

While the forms of apparatus herein described constitute preferred embodiments of the invention, it is to be understood that this invention is not limited to these precise forms of apparatus and that changes may be made therein without departing from the scope of the invention.

What is claimed is:

1. Apparatus for supporting an endless paper machine forming wire or the like, comprising an elongated tube positioned transversely of the path of the wire, a non-rotatable shaft extending through said tube and having opposite end portions projecting beyond both ends of said tube, said tube having a greater inner diameter than the outer diameter of said shaft to define an annular clearance therebetween, means defining a discharge outlet from each end of said annular clearance, stop means limiting axial movement of said tube on said shaft, means defining a pasage within said shaft extending from an inlet in one of said projecting end portions to an outlet port communicating with said annular clearance at a location within the top portion of said shaft and intermediate said stop means, a support member for each said end portion of said shaft, pivot means connecting each said support member to the corresponding said end portion of said shaft, means for stressing said shaft to compensate for deflection thereof due to the weight of said tube and said shaft between said end portions, means supporting each said shaft support member for adjustment in a vertical direction for positioning said tube at a predetermined elevation, and means for connecting said inlet to a source of pressure fluid for maintaining said annular clearance full of such fluid to support said tube substantially free of said shaft for free rotation in response to engagement by said wire.

2. Apparatus as defined in claim 1 comprising adjustable means connected to said end portion of said shaft and located axially outwardly of said pivot means for stressing said shaft about said pivot means to compensate for deflection thereof.

3. Apparatus as defined in claim 1 wherein said shaft is hollow, and including a head closing each said end portion of said hallow shaft, means forming an inlet through one of said heads to said outlet port, and adjustable tensioning means connecting said heads through said hollow shaft for stressing said shaft to compensate for deflection thereof.

4. Apparatus as defined in claim 1 wherein said shaft is of metal and said tube is of a plastic material.

5. Apparatus for supporting an endless paper machine forming wire or the like, comprising a box having a bottom and side and end Walls defining a chamber, means for connecting the interior of said chamber to a source of suction, a plurality of rolls forming a top wall for said chamber, each said roll comprising an elongated shaft having opposite end portions non-rotatably mounted on said side walls, an elongated tube mounted on each said shaft, each said tube having an inner diameter greater than the outer diameter of the corresponding said shaft to define an annular clearance therebetween, means for limiting axial movement of each said tube on its corresponding said shaft, means defining a discharge outlet from each end of said annular clearance, means defining a passage within each said shaft and extending from an inlet adjacent one of said end portions to an outlet port communicating with said clearance at a location within the top portion of said shaft intermediate the ends of said tube thereon, and means for connecting each of said inlets to a source of pressure fluid for maintaining said clearances full of such fluid for supporting said tubes substantially free of said shafts during rotation in response to engagement by the Wire.

6. Apparatus as defined in claim 5 comprising a plurality of said tubes rotatably mounted on each said shaft in axially spaced relation, and intermediate brace for said shafts engaging each said shaft between said tubes thereon to support said shafts against downward deflection.

7. Apparatus as defined in claim 6 wherein said intermediate braces for adjacent said shafts are offset laterally with respect to each other.

8. Apparatus as defined in claim 5 comprising a continuous perforated belt looped around the ends of said suction box for continuous travel on said tubes.

9. Apparatus for supporting an endless paper machine forming wire or the like, comprising an elongated table roll including a tube, a non-rotatable shaft extending through said tube and having opposite end portions projecting beyond both ends of said tube, a support member connected to each said shaft end portion, a base member for each said support member, rotating means connecting each said support member to the corresponding said base member for movement of said support members relative to said base members, means for discharging a supply of pressure fluid from the top portion of said shaft into the space between said tube and said shaft, and means for adjusting each said support member relative to the corresponding said base member in a vertical direction for positioning said roll at a predetermined elevation.

References Cited UNITED STATES PATENTS 3,012,301 12/1961 Rogers et al. 162270 XR 2,054,214 9/1936 Buss 162-197 2,773,433 12/1956 Mathias 162373 S. LEON BASHORE, Primary Examiner R. H. TUSHIN, Assistant Examiner US. Cl. X.R.

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