US2981329A

US2981329A - Fluid floated belt for suction boxes

Info

Publication number: US2981329A
Application number: US771546A
Authority: US
Inventors: Edgar J Justus
Original assignee: Beloit Iron Works Inc
Current assignee: Beloit Iron Works Inc
Priority date: 1958-11-03
Filing date: 1958-11-03
Publication date: 1961-04-25
Anticipated expiration: 1978-04-25

Description

April 25, 196] E. J. JUSTUS 2,981,329

FLUID FLOATED BELT FOR SUCTION BOXES Filed Nov. 5, 1958 /0 E 1 b 1 /5 (E 9) 0 {4 WHIWW" IW'W 2 Sheets-Sheet l ha 21hr 509612" c[ cfus fus April 1961 E. J. JUSTUS 2,981,329

FLUID FLOATED BELT FOR SUCTION BOXES Filed Nov. 3, 1958 Egw 2 Sheets-Sheet 2 Edgar cf r/usfus Z: 7 741; Z'Q/ Q'QQZ Z E FLUID FLOATED BELT FOR SUCTION BOXES Edgar J. Justus, Beloit, Wis., assignor to Beloit Iron Works, Beloit, Wis., a corporation of Wisconsin Filed Nov. 3, 1958, Ser. N 771,546

Claims. (Cl. 162--367) The present invention relates broadly to paper machines, and is more particularly concerned with new and improved means having especial utility in the support of the moving belt traveling in contact with the forming wire and suction box in the Fourdrinier type paper machine.

As is well known, the conventional Fourdrinier type paper machine comprises a looped traveling forming wire presenting a forming reach extending from a breast roll, at which the stock is flowing onto the wire, to a suction couch roll located approximately at the station at which the formed web is removed from the wire. Various dewatering devices are mounted beneath this reach of the forming wire, and one of the more common dewatering devices is known as a suction box and presents a flat perforate top to the bottom side of the wire. The interior of the suction box is exhausted to assist in drawing water from the web through the wire and through the perforations in the fiat top of the suction box. The pressure dififerential which is thereby created tends to hold the traveling wire down against the stationary flat top of the suction box so as to increase wear on the wire.

Various devices have been suggested for the purpose of avoiding wire wear caused by drawing the moving wire over fixed suction boxes, and one of the most well known of these devices is often referred to as the Evans Roto Belt, which is described and claimed in US. Patent No. 2,039,308, issued to William P. Evans on May 5, 1936. In the Evans structure a perforated moving belt with solid edges is installed between the traveling Fourdrinier wire and the suction box covers in an attempt to reduce wire wear and also wear on the suction box covers. The conventional manner of driving the moving belt is by means of two main rolls which form the loop of the belt. Numerous difiiculties arise from the use of the driven rolls, and one serious problem presented is maintaining the rolls properly balanced with respect to each other so that the moving belt is at all times tensioned to the proper degree. Thus, if either of the rolls is not properly centered with respect to a predetermined point, or one roll driven at a greater speed than the other, smooth and efficient operation of the paper machine cannot be obtained. Second, the two main rolls add substantially to'the installation and operating costs of the paper machine.

The instant invention resides in a novel, simple and particularly efiective arrangement for overcoming these difficulties. In accordance with the present teachings, the moving belt is supported at opposite ends of the suction box by an arcuately shaped lubricated member extending essentially entirely across the full width of the belt and provided with a transverse lubricating groove in preferably the oncoming face thereof. Each member or shoe as constructed in accordance with the principles of this invention is lubricated with water, and the groove formed therein has a generally rounded U-shaped crosssection with an outwardly flared rounded discharge lip so that the water can flow uniformly out of the groove over the lip to provide a lubricating film on the surface of the shoe under the belt. One manner of assuring uniform distribution of the lubricating water along the length of the groove is to employ a header pipe having a series of stems connected to the bottom of the groove at spaced intervals along the length thereof.

It is accordingly an important aim of the present invention. to provide an improved paper machine, and more particularly, to provide novel means for supporting the moving belt traveling over a suction box in a Fourdrinier type paper machine.

Another object of this invention lies in the provision of lubricated members positioned at the oncoming and ofirunning sides of a suction box which eflectively support the moving belt, reduce the wear thereon, seal the belt-suction box interface against the entry of air, and which may be readily fabricated, installed and removed.

Other objects and advantages of the invention will be come apparent during the course of the following description, particularly when taken in connection with the accompanying drawings.

In the drawings: a

Figure 1 is an essentially diagrammatic elevational view of a paper machine embodying belt support means constructed in accordance with the principles of this invention;

Figure 2 is an enlarged view of a preferred form of suction box and further showing the lubricated belt sup port means of this invention;

Figure 3 is an enlarged sectional fragmentary detail view taken substantially along the line III-III of Figure 2, with parts shown diagrammatically;

Figure 4 is a detail view of a portion of one lubricating belt support member, showing the groove construction therein and one form of water inlet which may be employed;

Figure 5 is a sectional view taken substantially along the line VV of Figure 4; and

Figure 6 is a fragmentary detail top plan view. of a suction box cover which may be utilized in connection with the present invention.

Referring now to the drawings, there is shown in Figures 1 and 2 a paper machine indicated generally by the reference numeral 10, and comprising a looped forming wire 11 trained over a breast roll 12, table rolls 13, suction box 14, a couch roll 15, a turning roll 16, and return rolls 17. Stock is deposited on the upper wire run 11a from a head box 18 in the region of the breast roll 12, and the stock is dewatered during its travel on the upper wire run 11a to form a web W which is removed from the wire 11 by a pickup felt 19 urged against the web W by a suction pickup roll 20. A rotary belt 21 mounted on support means 22 and 23 in accordance with the principles of this invention is interposed between the suction box 14 and the wire run 11a and may be guided during its travel by a roll 24 or by ribs or rails associated with the support means 22 and 23.

The present invention is directed to the lubricated support means 22 and 23 in association with a moving belt and suction box in aiFourdrinier type paper machine as shown in Figure l. The structural details of the suction box 14 and traveling belt 21 shown in the drawings form no part of this invention, and the illustrative suction box and movable belt are shown in some detail only to facilitate an understanding of the present invention. Accordingly, it will be appreciated that other suction boxes and movable belt may be substituted in lieu of the structures shown, although the illustrated constructions have proven in practice to have substantial advantages over the earlier arrangements. a

The suctionbox 14 is equipped with. a generally flat top 14a having perforations 14b therein which open into the interior 14c. Exhaust means in the form of a pump 25 (shown diagrammatically) connect to drop legs 14d of the suction box 14 for the purpose of exhausting the interior 14:: to eifect dewatering of the web W through the perforations 14b. As appears inFigures 3 and 6, said perforations are countersunk at their upper ends.

As is indicated in Figure 2, the perforations 14b in the suction box top 14a are spaced longitudinally in the direction of wire travel. As shown in Figure 3, the perforations 14b in the suction box top or cover 14a are also spaced laterally and there are land areas Me on the generally flat upper face of the cover 14a. Such land areas 14e are intermediate the perforations 14b, and actually provide the supporting surface for the cover 14a that supports the traveling belt 21 moving thereover. It is to be further seen from Figure 3 that the land areas 14:; are provided with shallow grooves 14f which face the belt 21 traveling thereover, the grooves being closed off from the interior 140 of the suction-box 14. Further, as shown in Figure 6, relatively shallow, longitudinally spaced, and lateral extending grooves 14g communicate with the grooves 14 to provide a substantial lubricated area whereby resistance to belt movemen't'is reduced. As here shown, the land areas He mounting the grooves 14], as well as the grooves themselves, extend longitudinally of the direction of wire travel indicated by an arrow in Figure 2. The grooves 14 extend from near the ofi-running edge of the suction box cover 14a to near the oncoming edge.

As indicated diagrammatically in Figure 3, means con nected to a source of liquid under pressure communicate with the grooves 14, and 14g for flowing liquid between the bottom side of the belt 21 and the suction box top 1411 to lubricate the same. Such means indicated generally at 26 include a pump 27, a pressure control valve 28 (for maintaining a predetermined pressure in water header 29), and conduits 30 extending from the header 29 to the grooves 14 As indicated by the arrows in dashed lines in Figure 6, the water flows from the groove 141 along the land areas 14a and ultimately to the countersunk perforations 14b in the cover 14a. The flow indicated in Figure 6 is very slight and is controlled by the pressure of the belt 21 against the areas 14c, however, the flow is 'sufiicient 'to lubricate the rubber belt 21 and to prevent dragging thereof over the dry land areas Me. As is appreciated, other grooving arrangements may be employed.

The belt'21is provided with perforations or drainage holes 21a, .as indicated in Figure 3, and said holes are so mounted in the traveling belt that. they do not align themselves with the grooves 14 in the suction box cover 1411. In thisway water is not forced back up through the drainage holes 21a. Instead, the drainage holes 21a periodically align themselves with the perforations 14b in the suction box cover 14a. The bottom side of the belt 21 has, of course. a'number of openings therein formed by the drainage holes. 21a. Intermediate said drainage holes there are land areas 21b on the bottom side of the belt 21 which cover the grooves 14 in the land areas 14c on the top side of the suction box cover 14a. These belt land areas 21b are urged downwardly against the suction box land areas 14s by the pressure differential created by the suction box 14. For this reason, water is urged into the grooves 14 under slight pressure to effect continuous seepage of water between the faces of the land areas 148 and 21b, this seepage being necessary to prevent the rubber belt 21 from wiping the land areas 14:: dry and thereby increasing the frictional drag. Preferably, theseepage of water is very slight so as not to overload the water removal system for the suction box 14.

The top side ofthe belt 21 is preferably provided with a plurality of longitudinally spaced laterally extending grooves 01' channels 21c, one of which is shown in Figure 3. Each such groove 21c is provided with one or more drainage holes 21a, which as earlier noted perimeans 22 and 23 which are the essence of the invention herein disclosed.

As appears in Figures 1 and 2, the belt support means 22 is located at the oncoming side of the vacuum box 14, 7

while the belt support means 23 is positioned at the offrunning side thereof. The support means 22 and 23 may be attached in any suitable manner to fixed structure, and this may include a securement to the suction box or to other machine structure. The lubricated belt support devices are essentially identical as to shape and construction to permit interchangeability, and in view of their structural identity only one of the support means will be specifically herein described.

'Each supporting member or

shoe

22 or 23 extends essentially entirely across the full width of the belt 21 to be in continuous contact therewith prior to and after the belt moves along the suction box cover 14a. Each lubricated shoe 'is'of generally arcuate shape and includes a curved main body portion 31 integral with a generally straight end portion '32 to provide an essentially fiat run for the belt prior to passage across the suction box 14. The supporting

shoes

22 and 23 are constructed of steel or the like, and in their preferred form are provided with generally fiat inner and

outer faces

33 and 34, respectively, which extend generally parallel to one another. The outer belt contacting surface 34 is preferably smooth and polished to minimize frictional losses.

Each shoe has an oncoming end 35 and off-running end 36, and it is to be seen that the end 35 of the shoe 22 is preferably curved as at 3511 to prevent belt damage. The end 36 of the shoe 22 abuts against the oncoming side of the suction box cover 14a, as shown best in Figure 2. Spaced circumferentially from the oncoming end 35 of each lubricated shoe is a groove or open passage 3 extending transversely of the shoe. It is to be seen that the groove is formed along the contacting face 34 of the shoe and is generally U-shaped in crosssection. The groove, however, preferably has a generally rouned bottom or base 38 and an outwardly flared rounded discharge lip 39 "so that the lubricant can fiow uniformly out of the groove 37 over the lip 39 to provide a lubricating film on the surface 34 contacting the inner face of the belt 21. Experience has indicated that water performs efiectively as a lubricant in the present instance.

Various arrangements may, of course, be utilized to supply water to the groove '37 in the

shoes

22 and 23, and one system comprises a pump 40 (Figure 2) connecting with a water header 41 which is in turn suitably passaged to communicate with a plurality of pipe lines or stems 42 terminating at their opposite ends in the groove 37. In this manner water is directed to the transverse groove 37 at a plurality of spaced locations along the length thereof. As is shown in Figures 4 and 5, the

shoes

22 or 23 are bored as at 43 to receive the stems 42.

It may be desirable in certain applications to guide the belt 21 during movement along the

shoes

22 and 23 and across the suction box cover 14a. The guide arrangement may take any one of several forms, including arcuate ribs or rails on the

shoes

22 and 23, suitable rails may be employed at opposite ends of the suction box 14, or a single roll 24 havinga flange 44 provided thereon may be utilized, as is shown in Figure 2. In other applications, on the other hand, the roll 24 may notbe required since the supporting shoes or

members

22 and 23 provide the necessary belt tension.

As earlier noted, it has previously been believed necessary to drive the belt 21 over the suction box 14 by a pair of main rolls positionedat the oncoming .and 0E- running sides of-said'bbx. Howevenit'ha's been found that the belt 21 may be driven adequately by contact with the Fourdrinier wire W, and accordingly, the external drive means employed in prior art arrangements can be eliminated. Of course, the water pressure supplied to the vacuum box surface by the pump 25 of Figure 2 must be sufficient to balance the vacuum forces and the weights of the belt, wire and slurry deposited thereon. Accordingly, by elimination of the two main rolls which formed the loop of thebelt in the prior art structures, the associated problems of imbalance and substantial costs of installation and operation are eliminated by the present invention. In this connection, it may be found that upon initial belt travel a greater water pressure will be necessary to the lubricated

shoes

22 and 23, however, during normal continuous operation when the belt is properly tensioned the water pressure will be reduced.

In addition to the noted advantages of eliminating the out-of-balance condition of the earlier used rolls, and the cost disadvantages associated therewith, the method of the present invention by the steps of directing a continuous belt along a stationary arcuate path and lubricating the belt during said travel the further advantages of reducing friction losses and belt wear are obtained. In addition, as is now apparent, reduction of frictional losses and elimination of roll imbalance assures that the paper machine may be operated at maximum speed and efliciency.

The sealing against the admission of air between the belt and the suction box surface has the quite evident advantage of reducing the vacuum pump capacity required and the volume necessary to handle inasmuch as the water preferably used is not expansible. This feature has the unobvious advantage of reducing the total load obtained at a particular degree of vacuum since it re duces the area over which the vacuum operates to press the belt against the flat surface.

It will be understood that modifications and variations may be effected without departing from the spirit and scope of the novel concepts of the present invention.

I claim as my invention:

1. In a paper machine which includes a suction box, a traveling wire and an endless perforated belt of generally the same width as the box movable by said wire over said box, the improvement which comprises stationary support means forming the loop of the endless belt and extending essentially entirely across the width thereof, said support means being passaged to provide a lubricating groove opening toward the endless belt, and means for supplying lubricant to said groove.

2. In a paper machine which includes a suction box, a traveling wire and an endless perforated belt of generally the same Width as the box movable by said wire over said box, the improvement which comprises stationary support means of generally arcuate shape forming the loop of the endless belt and coextensive with the width thereof, the belt contacting face of the support means being formed with a groove generally U-shaped in cross-section having a discharge lip flared outwardly in the direction of belt travel, and means for supplying lubricant to said groove.

3. In a paper machine which includes a suction box, a traveling wire and an endless perforated belt of generally the same width as the box movable by said wire over said box, the improvement which comprises stationary support means of generally arcuate shape forming the loop of the endless belt and coextensive with the width thereof, the belt contacting face of the support means being formed adjacent the oncoming end thereof with a transverse groove of generally U-shape crosssection having a mouth of relatively greater circumferential length than the base to provide a discharge lip, and means for supplying lubricant to said groove.

4. In a paper machine which includes a suction box,

a traveling wire and an endless perforated belt of generally the same width' as the box movable by said wire over said box, the improvement which comprises a gen-' erally arcuate belt supporting member at both the oncoming and off-running sides of the suction box and forming the loop of the belt, each of said members having a generally flat belt contacting face provided therealong with a transversely extending generally rounded lubricating groove, and means connecting with said groove at a plurality of spaced locations therealong to direct water to said groove and along the belt contacting face of the member to lubricate said belt.

5. In a paper machine which includes a suction box, a traveling wire and an endless perforated belt of gen erally the same width as the box movable by said wire over said box, the improvement which comprises a general-1y arcuate belt supporting member at-both the oncoming and ofimunning sides of the suction boxand forming the loop of the belt, each of said members having a generally flat belt contacting face provided therealong with a transversely extending generally rounded lubricating groove, said groove having a mouth portion of relatively greater circumferential length than the bottom thereof to provide a discharge lip outwardly flared in the direction of belt travel, and means connecting with said groove at a plurality of spaced locations therealong to direct water to said groove and along the belt contacting face of the member to lubricate said belt.

6. In a paper machine which includes a suction box, a traveling wire and an endless perforated belt of gen erally the same width as the box movable by said wire over said box, the improvement which comprises a generally arcuate belt supporting member at both the oncoming and off-running sides of the suction box and forming the loop of the belt, each of said members having a generally flat belt contacting face provided therealong with a transversely extending generally rounded lubricating groove, said groove being spaced relatively more closely to the oncoming end of the member than to the off-running end thereof and having a rounded discharge lip flared outwardly in the direction of belt travel to provide a uniform thickness lubricating film on the belt coextensive with the witdh thereof, and means connecting with said groove at a plurality of spaced locations therealong to direct water to said groove and along the belt contacting face of the member to lubricate said belt.

7. Means for supporting an endless perforated belt traveling over a suction box in contact with a forming wire, said means comprising a generally arcuate member extending generally entirely across the width of the belt and said suction box, said member being provided on its belt contacting face with a generally U-shaped cross-section lubricating groove provided with a discharge lip flared outwardly in the direction of belt travel to apply a generally uniform thickness lubricating film be tween the belt and contacting face of the member.

8. Means for supporting an endless perforated belt traveling over a suction box in contact with a forming wire, said means comprising a generally arcuate member extending generally entirely across the width of the belt and said suction box, said member being provided on its belt contacting face with a transverse generally U-shaped cross-section lubricating groove having a rounded bottom and a rounded discharge lip flared outwardly inthe direction of belt travel to apply a lubricating film of uniform thickness between the belt and contacting face of the member, the groove in said member being relatively closer to the oncoming end than the olfrunning end thereof.

9. In a paper machine which includes a suction box,

ing a generally; flat belt, contacting face provided therealong with a transversely extending: generally rounded lubricating groove; said groove having a mouth portion of; relatively greater: circumferential length than the bottom thereofto provide a discharge lip outwardly:

flared in the direction of belt travel, and means connecting with said groove at a plurality of spaced locations therealong to direct water to said groove and along the belt contacting face of the member to lubricate said belt,

10. In a paper machine which includes a; suction box, 15

a traveling wire and an endless perforated belt of generally the same width as the box movable by said wire over said box, the improvement which comprises. statthereof, said support means being" provided With an,

opening for the supply of lubricant to the inner suliface" of said belt during movement along said support means, and means for supplying lubricant to said opening for application to the belt inner surface.

References Cited in the file of this patent UNITED STATES PATENTS Evans June24, 1952 FOREIGN PATENTS Germany July 15, 1-899