US2173317A - Felt conditioner for paper-making machines - Google Patents

Description

Sept. 19, 1939. Fjw WC ERY 2,173,317.

FELT CONDITIONER FOR PAPER-MAKING MACHINES Filed Feb. 27, 1937 v 4 Sheets-Sheet l 1 l i r I I v &

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Sept. 19,1939. F. WQVI'cKERY 2, 7

FELT CONDITIONER FOR PAPER-MAKING MACHINES Filed Feb. 27, 1937 4 Sheets-Sheet 2 73 36 //vv/vr0R ATTORNEY Sept. 19, 1939. v F. w. VICKERY 2,173,317

FELT CONDITIONER FOR PAPER-MAKING MACHINES Filed Feb. 27, 1937 4 Sheets-Sheet s Armswsr Sept. 19, 1939.

' FEM" CONDITIONER FOR PAPER-MAKING MACHINES Filed Feb. 27, 1937 4 -Sheet 4 F. w. VICKERY 2,173,317"

Patented Sept. 19, 1939 UNITED STATES FELT CONDITIONER FOR PAPER-MAKING MACHINES Frederick William Vickery, Westminster Bridge, London, England Application February 27, 1937, Serial No. 128,283

In Great Britain February 1, 1937 2 Claims.

This invention relates to the reconditioning of the felts of paper-making machines, by applying a reconditioning fluid, usually water, to the felt and immediately thereafter withdrawing it and the dirt dislodged by it by suction.

The object of the invention is an apparatus that will perform these operations with economy of power expenditure in the suction and pumping plant, with a minimum of wear upon the felt,

and so as to leave the felt in substantially uniform condition particularly as regards moisture content.

To achieve this object the apparatus of the invention combines a suction box of less than the full working width of the felt maintained under high vacuum and separated from the felt by a'narrow perforated endless band; a nozzle delivering fluid upon the surface of the felt in advance of the point at which the suction box operates; guard means for confining the fluid delivered by the jet to the width of felt upon which the suction b'ox is aboutv to operate; and means for traversing the suction box, together with the nozzle and its guard means, to and fro across the felt.

The narrow suction box calls for only a small expenditure of power in the suction plant to maintain a considerable degree of vacuum within it; and a considerable degree of vacuum is made possible without undue wear on the felt by the transference of wear mainly to the rubbing surfaces of the suction box and the interposed endless band; but because the suction box is narrow the fluid delivered by the nozzle must be confined v to less than the width of the suction box, for

if it substantially wets the felt beyond the width upon which the suction box will straightway thereafter act, wet streaks may be left in the felt which will impair the uniformity of the product,

While the fluid delivered by the jet may be sufficiently confined, for many purposes, by guard walls lightly contacting with the felt on each side of it, it may be desirable, particularly where the jet is powerful, to support the felt against the thrust or lift of the jet, by holding it clown upon the jet by suction. To this end the invention contemplates the use of a suction box maintained at a relatively low suction, extending along opposite sides of the jet or surrounding it on three sides or wholly. This ensures penetration of the fluid into the felt and obviates any possibility of the felt being lifted so as to allow lateral escape of'the fluid.

The endless band may be a flexible band, which ll has the advantage that it can be deformed to follow a substantially straight path where it contacts with the felt and so prolong the time of action upon the felt. Or it may be a stiff ring to which external support can be given to diminish to any desired extent the pressure of 5 the ring upon the suction box.

Other features of the invention will most conveniently be described with reference to the specific embodiments of the invention illustrated in the accompanying drawings.

In these drawings,

Figures 1, 2 and 3 are respectively a longitudinal section, a plan (with the ring in section) and an end elevation (omitting the ring)i. e. an elevation looking lengthwise of the felt-of a 5 construction with a stiff ring;

Figures 4 and 5 show modifications that may be embodied in this construction.

.Figures 6 and 7 are diagrammatic longitudinal and transverse sections of a construction with a 0 flexible band; e

Figures 8 and 9 show further details of the band.

Figures 10 and 11 are diagrammatic longitudinal section and plan respectively of a further 5 modification.

In the construction shown in Figures 1 to 3 the conditionercomprises a carriage I and a separate suction box casting 2 adjustably mounted on the carriage by pin and slot connections 3. 30 The carriage rides upon an angle bar 4 which extends across the paper-making machine, and is moved to andfro by mechanism now well known of which Figure lshows only a half nut 5 adjustably supported from the carriage I be- 5 neath the bar 4. Connection is made at 6 to the interior of the suction box from a suitable suctlon pump.

' The surface of the suction box casting adjacent the felt 1 and around the mouth 8 is 40 made cylindrical to fit a stiff perforated ring 9 which contacts with the felt I and turns upon the suc tionmox casting. The ring may be of metal/but preferably it is built up of fabric impregnated with synthetic resin. It is kept 5 concentric with the surface of the suction box by guides l0 adjustably secured upon the edges of the carriage l. Laterally the ring is confined between flanges II on the suction box casting 2 V and by projections l2 on the guides ID, as ap- 5o pears more clearly from Figure 3 from which the ring itself has been omitted. If desired the lateral guides H and I2 may contact with the ring 9 at a few points only, and the ring may be made with Wavy edges (compare Figure 11), so

that as it turns it will be moved slightly from side to side upon the suction box carrying with it the part of the felt with which it is in contact.

If a conditioning fluid is employed it may conveniently be injected by the flat nozzle I3 into the angle between the ring 9 and the felt I; the nozzle I3 is carried upon a bracket I4 secured upon the suction box 2, and should be setat such an angle that at least a part of the fluid penetrates the felt.

To confine the fluid laterally guard walls 34 are fitted on each side of the jet, lightly touching the felt. They may be joined by a bottom plate 35 which will serve to carry off all fluid not temporarily retained in the felt. In addition an interchangeable cross-bar 36 may be provided joining the top edges of the guard walls 34, and adjustable to scrape the surface of the felt. This will remove a great deal of the dirt and some.

more of the cleaning fluid, all of which material will be led away by the chute formed of the guide walls 34 and sloping bottom plate 35.

Wear between the ring 9 and the suction box casting may be reduced by suitable lubrication. For instance renewable 'graphitic or other antifriction blocks may be inset in the cylindrical surface of the casting as diagrammatically indicated at 31. Or water may be injected through a pipe l5 and channels such as l6 opening on the cylindrical surface. Once the ring 9 has begun to turn the water supply to the pipe l5 may be cut off, and water may be carried to the rubbing surfaces by means of buckets l1 formed in the inner surface of the ring 9 at its edges, or felt pads l8 set in that surface. These may be filled or impregnated by the water draining from the felt or by the cleaning jet 43 directed upon the inner face of the ring 9. v

A further-alternative means of lessening friction between the ring 9 and the suction box is to provide a yielding support to take the weight of the ring and the pressure of the felt upon it. For example as shown in Figure 4 a roller l9 bearing on the outer surface of the ring diametrally opposite the suction box, may be carried upon a pivoted arm 20 ,and resiliently pressed against the roll. Figure 4 shows the arm 28 con nected to a piston 2| moving-in a cylinder 22 which communicates with the suction box so that the greater the vacuum in the suction box the more strongly is the ring supported against the pressure of the felt which is drawn by the suction towards the suction box. By suitable choice of the size of the piston 2| or by shifting its point of connection to the arm 20 the amount of lift given to the ring 9 can be adjusted to the best value for diminishing friction without occasioning leakage. The friction, upon a suction roll .extending the full width of a felt may be reduced in similar fashion.

The suction box may be yieldingly supported so that it can adapt itself to some extent to the ring in case the ring is displaced by the drag of the felt and maintain an even distribution of the pressure of the felt upon it. Figure 5, for example, shows the suction box formed at the off-going side with a rounded end 23 which rests on a fixed support 24 upon the carriage, while at the oncoming side the box rests on an adjustable abutment 25 and is guided bypins 26 entering slots 21.

Instead of being a. stiifring the perforated band interposed between suction box and feltmay be flexible. If desired the suction box may then, as indicated in Figure 6, have a substantially flat top extending parallel withthe felt to any desired length. Thus the time during which the felt is subject to suction need not be limited by the size of the ring 9 and its arc of contact with the felt.. Figure 6 shows the band as consisting of a flexible endless strip of non-rusting steel 28 to which are riveted shallow open rubber boxes 29, having openings in their bottoms registering with perforations in the band 28.

Where it passes over the flat surface of the suction box the band 28 is deformed into a straight path by flanges 38 on the suction box, and due to these and the suction the band is held tight upon renewable lubricating strips 3| set in the edges of the suction boxes.v In the rest of its path the band may assume a substantially circular form without support, though a guide or guard 32 may be formed on the suction box casting within or beside the band. The rubber boxes 29 should be wedge-shaped so that their edges remain in contact even where the band assumes a circular form, and their ends are preferably bowed out as seen at 33 in Figure 8 so that they will readily yield to allow the narrowing and lengthening of the boxes which occurs as they pass on to the straight part of their path.

Alternatively the flexible band may be of rubber and canvas fabric, andbe fitted with transversely divided renewable ribs of hard rubber in lieu of the boxes 29. On the straight lengths of the band the blocks of which the ribs are formed come into contact, or may tenonone into the other so as to make a substantially air-tight joint.

An alternative means of confining the conditioning fluid to the narrow strip of the felt on which the travelling suction box is working is shown in Figures 10 and 11. Instead of the simple guard walls 34 a suction box 38 is provided extending along opposite sides of the jet l3 or surrounding it on three sides or completely. But as only light contact is desired between this guard and the felt, the vacuum within the box 38 should be much less than that within the suction box 2. To this end a valve or other constriction 39 is placed in the branch pipe 40 which connects the suction box 38 to the main suction pipe 4|; and between thisconstriction 39 and the suction box 38 there is provided an inwardly opening valve 42 which can be set to open at any desired pressure difference.

I claim:

1. A felt conditioner comprising a support extending across the whole width of the felt parallel to the felt, a carriage thereon, means for traversing said carriage along the support, a narrow suction box upon said carriage operating on a fraction of the working width of the felt, a perforated endless band passing between said suction box under a reduced vacuum as compared with the principal suction box.

2. A felt conditioner comprising a support extending across the whole width of the felt parallel to the felt, a carriage thereon, means for traversing said carriage along the support, a narrow suction box upon said carriage operating on a fraction of the working width of the felt, a. perforated endless band passing between said suction boxand the felt contacting with the perimeter of the suction box and surrounding it and the carriage, a nozzle upon said carriage directed into the angle between said endless band and the felt in advance of the suction box, an auxiliary suction box acting on the felt in rear of said nozzle and on each side of said nozzle from a. point in ad vance of said nozzle to the area acted on by the principal suction box, and means for maintaining said auxiliary suction box under a reduced vacuum as compared with the principal suction box.

FREDERICK WILLIAM VICKERY.

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