US2544572A - Felt conditioner for use in papermaking - Google Patents

Description

F. w. vlcKERY FELT commossa Fon usE In PAPERuAxmG March 6, 1951 5 Sheets-Sheet 1 Filed Nov. y16, 1948 Match 6, 1951 F. w. vlcKERY mur comm-10m Fon use In Mmmm@ 5 Sheets-Sheet 2 Filed Nov. 16. 19'48 l I WMMMMVVMMMV/l/I l IIIIIIIIII llllllIIII'IIIIIIIIIIIIIIIIIIIIIIIIIIIIII. I

March 6, 1951 l F. w. vlc-KERY 2,544,572

FELT commomza Fok usa 1N PAPERHAKING Filgd Nov. 16, 1948 5 Sheds-Sheet 3 30 :cr-.fg .u ,f I

l 2.9 I Z 21 26 l I ze 27 i. 20

March 6,1951 w. vlcKERY 2,544,572

FELT -CONDITIONER FOR USE IN FMERIAKING Filed Nov. 16, v'1948 5 Sheets-Sheet 4 32 M 30 r ,MI I 14] 2W/ [la Mardi 6 /1951 F. w. vlcKERY 2,544,572.l

FELT CONDITIONER FOR IJSII.l IN PAPERIIAKING Filed Nov. 16, 1948 5 Sheets-Sheet 5 o 156 .fang 137 I neder/tk Mfr/[iam WC1/eg, 4

Patented Mar. 6, 1951 FELT CONDITIONER FOR USE IN PAPERMAKING Frederick William Vickery, Guildford, England, assignor to Vickerys Limited, London, England Application November 16, 1948, Serial No. 60,253

In Great Britain November 18, 1947 Claims.

In Jordans U. S. Patent No. 2,368,662 there is described a felt conditioner shoe, comprising a plate adapted to contact a moving felt, and of less width than the felt, the plate having in its felt-contacting surface means for supplying cleaning fluid to the felt and means for applying vacuum to the felt, the huid-supplying means and the vacuum-applying means being alternated in the direction of travel of the felt so that the felt is subjected to `a number of rapidly alternatng cleaning cycles, each involving injection of cleaning fluid into the felt followed by extraction of a portion, at least, of the fluid injected. In the conditioner described in that specification the orices in the plate, hereinafter termed the jets, through which cleaning fluid ls injected into the felt are of equal width, measured in the direction of travel of the felt.

My investigations have shown that, in order to achieve maximum efficiency,l jets of different width are required at different parts of the length of the conditioner shoe. The arrangement of jets found most appropriate for use with one class of paper products is frequently, however, not that which will give maximum efliciency with a different class of paper products. Theoreticallyl the rst jet which the felt meets should be the widest, the second slightly narrower and so on to the last jet, but in actual practice with certain classes of products it may be found that, in order to obtain the best results, the first two jets should be of the same width, and again, in other cases, better results may be obtained by having the last two jets of theA same width. Moreover, with certain classes of paper products it may be desirable to eliminate one or more of the jets altogether.

Under modern conditions of fast travel of the felt the felt-contacting plate tends to wear rapidly as the result lof friction, particularly when the felt carries abrasive matter on it. The cutting of the slots in the plate is an expensive matter, and it is wasteful to have to discard a, plate on which expensive machining work is done after a short period of use due to excessive wear of the plate. It is therefore desirable to make the felt-contacting plate of as hard as possible a material. It is, however, diicult, if. not impossible, to cut fine slots for use as line water jets in a plate of hard material.

The object of this invention is to provide a felt conditioner shoe, of the kind having a plate .for contacting the felt formed with jets for supplying cleaning fluid to the felt and with holes 'for subjecting the felt to vacuum, and preferably of the kind in which the jets and vacuum holes are alternated so that the felt is subjected to rapidly alternating cleaning cycles each involving injection of cleaning fluid into the felt followed by vacuum extraction of cleaning uid from the felt, which may be readily adjusted, by substitution of a different arrangement of jets, so as to permit it to operate with maximum efciency over a wide range of operating conditions.

According to the invention, the jets are constituted by nozzles detachably mounted in slots in the felt-contacting plate of the conditioner shoe. By the provision of a number of nozzles having jet orices of different width the conditioner can readily be adapted to deal with different classes of work. All that the operator need do to adjust the ow of cleaning fluid to meet most eiiectively the requirements of any particular job, is to remove the plate from the body of the shoe, change any nozzles which require'replacement by nozzles having jet orifices of a different Width, and replace the-plate. In case a reduction in the number of nozzles should be required, a certain number of blank pieces of the same outside dimensions as the nozzles are supplied, and these are inserted and blank off the unneeded. slots in the felt-contacting plate.

By using interchangeable nozzles I am enabled to employ for the felt-contacting plate a material of any desired hardness, and at least a considerably harder material than is possible in the case of the conditioner described in the above-noted U. S. patent, because the slots in the plate can be relatively wide and iilled up, to reduce them as desired, by the insertion of nozzles having jet orifices of appropriate size.

Preferably the nozzles have at their lower ends (i. e; the ends remote from the felt-contacting surface of the plate) shoulders which fit into oorresponding recesses in the undersurface of the plate, or in the upper surface of the body of the shoe, these shoulders being of compressible resilient material, e. g. rubber, and standing slightly beyond the undersurface of the plate whenthe nozzles are in position, so that when the plate is fitted to the body of the shoe, and secured thereto, e. g. by nuts and bolts, the projecting portions of the shoulders will be compressed to form a seal between the portion of the body to which vacuum is applied and that to which the water or other cleaning fluid is supplied. Thus the nozzles may be made entirely of rubber. Alternatively they may be of the same material as the plate, e. g. of metal or plastic material.

and have washers of rubber or the like bonded to the undersurfaces of their shoulders, and projecting slightly beneath the plate when the nozzles are in position. Again, rubber washers separate from the nozzles may be used for effecting the seal.

I prefer to make the blank` pieces of the same material as the plate, e. g. metal or plastic material, and to provide these with rubber washers for effecting the seal, these washers being either bonded to or separate from the blank pieces.

Where, as is preferred, the nozzles are made of rubber or other resilient material, these can be moulded accurately to form therein jet orifices of the requisite width, and the resilient bodies will, provided the external dimensions of the nozzles are slightly greater than the dimensions of the slots in the plate, accommodate themselves t minor inaccuracies in dimensions of the slots which need not therefore be machined to a high degree of precision. 'I'his considerably simplifies the operation of cutting the slots i`n a plate of a hard grade of synthetic resin, which is the material preferably used for the plate,

Generally speaking, paper makers do not like their felts coming in contact with rubber, and at` irst sight it might appear that this would be an objection to the use of rubber nozzles, but in actual operation the felt is kept from making contact with the top of the rubber nozzle by the force of water issuing from it, which slightly lifts the felt. That is Why, when I desire to blank off a jet, I prefer to use blank pieces of the same material as the plate.

Some alternative forms of felt conditioner shoe according to the invention will now be described in detail, by way of example, with reference to the accompanying drawings. in which:

Fig. 1 is a plan view of the rst form of con` ditioner shoe;

Fig. 2 is a section taken on the line lI-lI in Fig. 1:

Figs. 3 and 4 are respectively sections taken on the lines III-III and IV-IV in Fig. 2;

. Fig. 5 is a longitudinal section through part of the top plate of the conditioner shown in Fig. l,`

the plate being removed from the conditioner and fitted with an alternative assemblage of nozzles;

Fig. 6 is a perspective view of one of the nozzles, partly cut away;

l Fig. 7 is a perspective view of one of the blank pieces;

Fig, 8 is a transverse section through an alter,- native form of conditioner shoe provided with means for clearing the jets and fitted with nozzles of slightly different form;

Fig. 9 is a section on the line IX-IX in Fig. 8;

Figs. 10-12 are views similar to Fig. 8' but showing alternative means for clearing the jets; and

Fig. 13 is a perspective view, partly cut away, of one of the nozzles shown in Figs. 8-12.

Like reference characters designate like parts throughout the figures.

Referring first to the conditioner shoe shown in Figs. 1-7, this is of the general construction described in the above-mentioned U. S. Patent No. 2,368,662. The body 20 of the shoe is constituted by a casting divided (see in particular Figs. 3 and 4) into a. suction chamber 2| and a water chamber 22. A number of transverse channels 23 (see also Fig. 2) communicate with thek water chamber 22 and extend across the suction chamber 2|, the channels 23 having slots 24 in their upper ends. A main suction inlet 25 is provided at one end oi' the suction chamber 2| and an auxiliary suction pipe 23 communicates with the other end of the suction chamber. A water inlet pipe 21 communicates with the water chamber 22. The body 20 carries two downwardly depending brackets 23 (Fig. 2) which are adapted to embrace guides extending transversely to the length of the felt to be cleaned, the conditioner shoe being moved, when in operation. to and fro transversely of the felt by any appropriate mechanism (not shown) such for example as that described in U. S. Patent No. 2,368,662.

To the body 20 is secured, by screws 29 (see in particular Fig. 3) a felt contacting plate 30. This may be made of metal but is preferably made of a hard grade thermosetting urea or phenolic molding materials.

'I'he plate 30 is formed with a number of transverse slots 3| (Fig. l) each of which registers with the slot 24 in one of the channels 23. It will be noted that the slots 3| are relatively wide and can therefore be cut without special diiiiculty even though the plate 30 is made of very hard material. The plate 30 also has cut in it a number of vacuum openings communicating with the suction chamber 2| Some of these vacuum openings 32 extend transversely to the length of the plate 30. The felt to be treated moves across the plate 30 from left to right as seen in Fig. l, and the transverse vacuum opening |32 last encountered by the felt is wider than the others. Others of the vacuum openings 33 extend obliquely, and opposite that end of each oblique opening 33 which is first contacted by the felt is a short transverse opening 34. The oblique openings 33 and short openings 34 have extensions 35 which are located adjacent opposite ends of the slots 3|. Extensions 35 of two short openings 34 are adjacent opposite ends of the rst slot 3|.

Into the slots 3| are removably fitted rubber nozzles 36. The nozzles 36 are formed with jet orifices 4| of appropriate width, and in the case shown in Fig. 2 it will be observed that the jet orifices 4| through which water is supplied to the felt decrease progressively in width from left to right. The external dimensions of the nozzles 36 are slightly greater than the dimensions of the slots 3| so that when the nozzles are pushed into the slots they may expand locally where necessary to accommodate any errors in machining of the slots. Each nozzle 36 has at its lower end a projecting shoulder 31 extending around all the sides of the nozzle. When the nozzles have been pushed into the slots 3|, their shoulders 31 are partly accommodated in recesses in thebase of the plate but project to some extent below the undersurface of the plate 30, as shown in Fig. 5, but when the plate is placed in the body of the shoe and secured thereto by the screws 29, the shoulders are compressed, as shown in Fig. 2, thereby forming a seal between the water channels 23 and the suction chamber 2|.

It will readily be understood that the nozzles 36 may be readily withdrawn from the plate 30 and replaced by others having jet orifices of different size when it is desired to alter the arrangement ci' water jets to suit a different class of work, and an alternative arrangement of jets is shown in Fig. 5. In this case one of the slots 3| has been closed altogether by a blank piece 33 (see also Fig. 7) made of the same material as the plate 30 and having a shoulder 39 of the same shape as the shoulders 31 on the nozzles.

'Il A rubber washer 40 is located beneath the shoulder 39 and acts, with the rubber shoulders 31, of the nozzles to form` a. seal between the suction chamber 2| and the water channel 23 over which the blank piece comes into place. 'I'he washer 40 is preferably bonded to the body of the blank piece, but a separate washer may be used, if preferred.

Instead of making the nozzles 36 of rubber they may like the blank pieces, be made of the same material as the plate, each having a shoulder andl rubber washer like the shoulder 39, and rubber washer 40 of the blank piece, the washer being either separate from or bonded to the body of the nozzle, as desired.

The nozzles |36 shown in Figs. Y8-13 differ slightly from those indicated at 36 in the construction shown in Figs. 1-7. They are likewise of rubber, but are slightly deeper, the whole of their shoulders |31 projecting below the lower surface of the plate and being accommodated in recesses in the body of the shoe. The recesses in the body are, of course, of slightly less depth than the shoulder |31 which they receive in order that the shoulders |31 may provide the required seal. Also in the case of the nozzles |36, the jet orifices |4| are not of the same width throughout their depth, as in the case of the jet orifices 4| of the nozzles 36, but increase gradually in width from bottom to top as shown in Fig. 9. This is to facilitate clearing of the jets, should they become choked, for which purpose the shoe body is provided with members which are operable to displace obstructing matter which may have accumulated in the narrow lower ends of the jets and either force it positively, or allow it to be carried by the water, out through the Wider upper ends of the jets.

In the shoe shown in Figs. 8 and 9 a plurality of clearing fingers 42 are provided, one for each jet, these being secured to a shaft 43 mounted for rotation in the body 26 of the shoe. The fingers normally occupy the position shown in full lines in Fig. 8, but on rotation of the shaft $3, by means of a crank handle applied to a squared part 44 of the shaft external to the shoe (see Fig. 9). the ends of the fingers may be thrust upwardly into their respective nozzles as shown in chain dotted lines in Fig. 8, to dislodge matter which may have accumulated in the narrower lower ends of the nozzles.

In the arrangement shown in Fig. 10, the fingers |42 are individually pivoted to the shoe body at dl and have forked ends 45 engaging cams 46 on the shaft 43, so that as the shaft is rotated the nger tips 50 will be moved upwardly to clear their respective nozzles.

In the construction shown in Fig. l1, each clearing finger 242 is pivoted at its lower end 49 to an arm 48 fixed to the shaft 43, and rests normally with its tip 50 engaging one side of the associated nozzle, as shown in full lines, each finger tip 50 being caused, by rotation of the shaft, to move across the width of its respective nozzle into the position shown in chaindotted lines to dislodge the accumulated matter and permit of removal of the same by the water.

In the arrangement shown in Fig. 12, individual clearing fingers 342 are provided, one for each jet, each finger having an `up/standing tip 5U which projects into the lower end of the nozzle and having at its other end a piece 5|, constituting a finger grip, which projects from the shoe body. The fingers 342 may thus be individually reciprocated, to clear their respective nozzles.

Where blank pieces are employed, they may be formed with shallow slots in their lower ends to receive the tips of the associated clearing fingers, so that when these fingers are operated by a. common shaft, the blank pieces will not obstruct movement of the fingers. Clearing fingers will normally only be required for nozzles of narrow width. I may therefore provide them for all the slots 3| in the plate. or alternatively only for those slots 3| into which it is likely that narrow nozzles wil be fitted under practical operating conditions.

The invention solves in the simplest and most effective way the problem of providing for variation from time to time in the size of the jets. The plates and the nozzles can be made in quantity on a mass production basis, andas already pointed out the operator can quickly and easily adapt the conditioner shoe to changing requirements by changing the nozzles.

It would not be satisfactory to cut nozzle-receiving slots of different widths in the plate. This would necessitate storing a large collection of plates, each having a different arrangement of slots. Also, for the reasons described above, the invention renders it unnecessary to cut narrow slots in the plate, and so allows a plate of extremely hard material to be used. Indeed' the slots 3| in the plate can be comparatively wide and the manufacture of nozzles with narrow jet orices to fit in the slots presents no difficulty since these can be made by moulding when of rubber or plastic material, or by casting when of metal.

Variation in the rate of flow of water through the jets could, of course, be achieved by the provision of valves in the body of the shoe for controlling the flow of water to the jets, or by the provision, within the shoe body, of removable bushings of different size in the conduits through which water flows to the jets. This would, however, be complicated and expensive in manufacture, and moreover would have the disadvantage that the water would issue at different pressures from the different jets. In the shoe according to the invention no variable area restriction is provided for the water on its way to the jets, and the Water will issue from the jets at the same pressure, but at different rates determined by the width of the jet orifices in the nozzles.

Conditions at some mills are such that maximum efficiency in conditioning of the felt cannot in fact be achieved, and a compromise is neces'- sary as between various opposing factors. The conditions of operation sometimes cannot be predicted in advance of the actual installation and operation of the mill. This invention enables easy adjustment of the conditioner to be effected after installation to the configuration, as regards distribution of jets, necessary to secure that maximum degree of efficiency permitted by the compromise. l

What I claim as my invention and desire to secure by Letters Patent is:

1. For use with a felt conditioner shoe having a vacuum chamber containing spaced channels of fluid supply, a cover plate for said shoe formed of hard rigid material, said plate having spaced openings to communicate with said vacuum chamber and spaced orifices to communicate with said fiuid supply channels, each of said orifices being elongated in the direction of the width lof the plate and each containing a detachably mounted nozzle formed of resilient material whereby to conform to the walls of the orifices and to form 7 a seal between `the vacuum chamber and the channels of iiuid supply, each of said nozzles having elongated iluid delivery apertures of predetermined cross-section.

2. A cover plate as set forth in claim 1 in which the apertures in consecutive nozzles are of decreasing width lengthwise of the cover plate/with the widest opening at the leading end of the plate and the narrowest opening at the trailing end.

3. A felt conditioner shoe having a cover plate 1o 8 5. A felt conditioner shoe as set forth in claim 3 in which individual means is provided for actuating each clearing finger.

FREDERICK WILLIAM VICKERY.

REFERENCES crrED The following references are of record in the ille of this patent:

UNITED STATES PATENTS Number Name Date.

259,131 Gould June 6, 1882 1,018,020 Werner Feb. 20, 1912 1,922,259 Paradise Aug. 15, 1933 2,148,535 Cone Feb. 28, 1939 2,368,662

Jordan Feb. 6, 1945

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