US3431608A - Apparatus for compacting fibrous webs - Google Patents

Description

March 1l, 1969 F. RElNl-:Rs

APPARATUS FOR COMPACTING FIBROUS WEBS Filed July 14, 1966 nited rates atent O M 66,004 U.S. Cl. 26-18.6 Int. CI. D06c 2]/00 2 Claims ABSTRACT F THE DISCLOSURE Apparatus for compacting a fibrous material web ncluding two rolls defining a compacting gap, and an elonga-ted nozzle of uniform cross -section extending parallel to the roll axes and directed toward the gap discharge and end to provide a pressurized fluid cushion supporting a web issuing from the gap. A container supplies pressurized fluid to the nozzle and has a volume compared to the nozzle volume that affords substantially constant fluid pressure distribution along the entire nozzle length. A device is located in the container upstream of the nozzle for maintaining constant the pressure of fluid issuing from the nozzle.

My invention relates to an apparatus for continuously and mechanically compacting webs which are flexible and made of a brous material such as textiles or other fibrous webs. Thus, the webs which may be compacted with the apparatus of my invention may take the form 0f woven or knitted fabrics, fibrous fleece, paper, and the like, as well as other types of sheet material which can be compacted, such as plastic webs with or without woven inserts or other layers. The apparatus of my invention acts in the webs as to compact the textile fibers or yarns, or in the case of plastics so as to compact the molecular chains :which extend longitudinally of the sheet material, so that in this way the webs treated with the apparatus of my invention have their length reduced and become elastically stretchable.

Machines which are capable of continuously and mechanically compacting flexible webs of fibrous material are already known. Thus, my invention relates to that type of compacting machine which is exemplified by U .S. Patents 2,263,712, 2,765,513, and 2,765,514, wherein the machine is provided with two or more rotary rolls adjusted to different rotary speeds with said rolls cooperating in pairs to clamp the web between the pairs of rolls las the web continuously advances along the rolls. The roll which rotates at the fastest speed is the first roll to engage the web and directs it to the other roll. A slide member or other device cooperates with the first roll to compel the web to travel at a speed corresponding to the circumferential rotary speed of this first roll. With one of the known compacting machines, the slower rotating roll has vat its outer surface a covering of a greater coefficient of friction than the first roll which rotates at a higher speed. At the location Where the web is clamped between a pair of rolls the speed of travel of the web is reduced by the extent to which the second -roll rotates at a surface speed less than that of the first roll, so that the second roll cooperates -with the first roll to retard the adice Vance of the web and to compact the web in this Way, inasmuch as the first roll continuously supplies additional web material to the second roll. The bucking of the web outwardly away from the rolls lbefore reaching the clamping position therebetween is prevented by providing a suitable narrow `space or gap in which the web is guided as it approaches the clamping position.

With these conventional machines, the web, after leaving the compacting gap 'between a pair of cooperating rolls, seeks to free itself of the compacting to which it has been subjected, so that -the web issues from the compacting gap a speed greater than the circumferential speed of the more slowly rotating compacting roll. Therefore, in the space which immediately follows `the compacting gap where the width of the gap gradually increases, transverse fold lines are formed in the web as long as there is pressure and friction between the web and the rolls. It is practically impossible -to eliminate these undesirable fold-s -from the web after it leaves the -compacting gap without also eliminating the compacting effects either entirely or to a very large extent.

It is accordingly a primary object of my invention to avoid this drawback.

In particular, therefore, it is an `object of my invention to provide a compacting apparatus of the above general -type which is capable of producing a compacted web of fibrous material which is free of any transverse folds.

Thus, it is an object of my invention to provide for a machine of the above general type a structure which will guide the web away from the compacting gap with so little friction and at a rate of speed and direction of movement which will reliably guarantee that the web will have no transverse fold lines therein while at the same time retaining the effects of the compacting action in the web.

Thus, in accordance with my invention there is situated in the region of the discharge end of the `compacting gap, in the space between the -pair of compacting rolls, a means which acts on the web to deflect it away from the more slowly rotating compacting roll. While this means of my invention can be composed of mechanical elements engaging the web, it is preferred to provide a means which deflects the web away from the more `slowly rotating compacting roll by providing for the web a fluid cushion in the form of air under pressure, steam at relatively high pressure, or even a liquid at suitable pressure.

Thus, while it is possible in accordance with my invention to use a variety of different fluids to form the cushion which supports and guides the web away from the compacting gap, it is preferred to use air under pressure for the fluid cushion.

The fluid medium which is used to deflect the web away from the more slowly rotating compacting roll flows substantially tangentially, which is t-o say as tangentially as possible, at an extremely sharp angle along both of the compacting rolls at that side of the compacting gap where its discharge end is located, and thus the web which is deflected away from the more slowly rotating roll is at the same time supported on the air cushion and directed away from the other rotating roll substantially tangentially with respect thereto. The fluid cushion is derived from a fluid which issues from a nozzle situated in the immediate vicinity of the discharge end of the compacting gap, and the closer this nozzle is to the gap the more relialbly the web is deflected away from the more slowly rotating compacting roll. Because of the streaming pressure uid which supports the web, the web is capable of sliding with substantially no friction along the uid cushion without forming any folds and without directly engaging the nozzle itself which forms the web-supporting air cushion. As a result the web can without any resistance relieve itself of the compacting which has been forced into the web to such an extent that the desired residual amount of compacting or shortening of the length of the web stably remains therein.

In order to maintain along the entire width of the web a constant uniform fluid pressure acting to deflect the web away from the more slowly rotating compacting roll, the nozzle which provides the air cushion is supplied by a container whose volume is so great with respect to that of the nozzle that there is available to pass through the nozzle a constant volume of air at a sufficiently high pressure to maintain the required uniform air cushion along the entire width of the web during the entire operation.

A comparison of the apparatus of my invention with the known machines has demonstrated that a given web of sheet material subjected to compacting by a predetermined differential in the speeds of rotation between a pair of rolls will with the known machines be transversely folded while with the apparatus of my invention under the same operating conditions the web will be completely free of folds and fully smooth while at the same time having the desired extent of compacting provided therein. This result has been achieved with my invention in a number of different tests with webs of different properties and with different degrees of compacting, which is to say at different relative circumferential speeds between the pair of cooperating rolls.

My invention is illustrated by way of example in the accompanying drawings which form part of this application and in which:

FIG. 1 is a partly sectional schematic elevation showing how a Web is compacted and then treated with the structure of my invention;

FIG. 2 is a fragmentary top plan view of the nozzle of FIG. 1;

FIG. 3 is a schematic side elevation of the machine which includes the structure of FIGS. 1 and 2; and

FIG. 4 is a fragmentary transverse section, taken along line 4-4 of FIG. 3 in the direction of the arrows, and showing, on an enlarged scale as compared to FIG. 3, one possible embodiment of a structure for adjusting the position of the nozzle.

Referring to FIG. 1, there is shown therein a first rotary roll 1 which turns in a counterclockwise direction, as viewed in FIG. l, and which serves to supply the web 3 to the compacting gap 9. A rotary second roll 2 is parallel to the roll 1 and defines the compacting gap 9 therewith. The circumferential speed of the roll 2 is less than that of the roll 1 so that the web 3 is retarded by the roll 2 as the web advances to the right, as viewed in FIG. 1, through the compacting gap 9. The roll 2 turns in a clockwise direction, as viewed in FIG. 1. A slide member 4 has a concave surface of the same curvature as the exterior surface of the roll 1 directed toward but spaced slightly from the exterior surface of the roll 1 so as to define with the latter an elongated space through which the web 3 is compelled to move as it approaches the entrance end of the ,compacting gap 9, this entrance end being situated at the left end of the gap 9, as viewed in FIG. 1. The web 3 has sliding contact with the concave surface of the slide member 4, and this slide member presses the web against the roll 1 so that the web is compelled to travel to the compacting gap 9 at the speed of movement of the surface of the roll 1. As is apparent from FIG. l, the slide member 4 may be in thefform of a hollow container to the interior of which a fluid such as steam may be provided so that this liuid can issue through the openings shown in FIG. l communieating with the concave surface of the slide member 4, and thus the fluid such as steam will have access to the web just before it reaches the compacting gap 9.

In accordance with my invention there is situated in the region of the discharge end of the compacting gap 9, this discharge and being situated at the right end of the gap 9, as viewed in FIG. 1, a deecting nozzle 5 which is supplied with fluid under pressure from a :container 6 which directly carries the nozzle S, being integrally formed with the nozzle 5 and of course having an interior which communicates with the interior of the nozzle 5.

The container 6 is supplied with air under pressure, and this pressure together with the volume of the container 6 are both sutiiciently great so that the nozzle 5 will provide along its entire length parallel and closely adjacent to the discharge end of the compacting gap 9 a uniform stream of air issuing at uniform pressure and having uniform characteristics along the entire length of the web. In order to enhance the uniformity with which the stream of iluid issues from the nozzle S, the structure includes a device 7, in the form of a perforated plate, situated in the interior of the container 6 just upstream of the nozzle 5 so as to uniformly distribute the fluid along the entire length of the nozzle S and so as to convert the pressure of the uid for the -most part into a movement of the fluid through the nozzle 5. Although the nozzle 5 can be provided with an elongated discharge slit of uniform width along its entire length, it is preferred to provide for the nozzle 5, as shown on an enlarged scale in FIG. 2, a plurality of closely spaced discharge openings S uniformly distributed along the entire length of the nozzle. The nozzle =is adjusted in a manner described in greater detail below in such a way that its elevational position with respect to the rolls 1 and 2 will provide from one part of the stream of compressed air issuing from the nozzle, as shown by the arrows 10, a flow of compressed air passing back over the upper part of the nozzle. One part of the yfluid issuing from the nozzle passes above the nozzle and the other part passes beneath the nozzle rearwardly along the underside thereof. The portion of the air which streams back over the nozzle forms the air cushion which supports the compacted web 3 issuing from the compacting gap 9 and which guides the web away from the compacting rolls without exerting any force on the web. Thus, it will be noted from FIG. l that the air cushion deects the web 3 away from the more slowly rotating compacting roll 2 and directs it sub stantially tangentally away from the roll 1.

With the apparatus of my invention the pressure of the air within the container 6 is maintained constant, and also the pressure of the fluid issuing from the nozzle is maintained at a high degree of uniformity and at an accurately determined constant value. Furthermore, the outlet of the nozzle is maintained precisely parallel to the compacting gap 9 between the rolls 1 and 2. The discharged openings, whether they take the form of an elongated slit or a series of closely spaced bores 8, very precisely maintain a uniform speed of flow of the fluid issuing from the nozzle and guarantee a uniform unchanging uid pressure over the entire length of the nozzle. It has been found that even a change on the order of a small fraction of a millimeter increasing or decreasing the passage through which the fluid flows at the discharge of the nozzle results in a lack of smoothness in the further transportation of the web 3 along the air cushion 10. For the purposes of my invention the elevation of the nozzle is adjusted in such a way that it is situated in the space immediately following the compacting gap 9 so as to provide a flow of approximately one half of the fluid issuing from the nozzle back over the upper part of the nozzle and of the remaining half of the fluid back beneath the nozzle. It is preferred, however, to provide fiowing along the top of the nozzle, forming the air cushion of my invention, a stream whose volume is slightly less than one half of the total volume of air issuing fnom the nozzle.

By situating with this structure of my invention a laminar flow fluid directed rearwardly along the upper part of the nozzle to form the air cushion, there is achieved at a predetermined elevation of the nozzle a ow of fluid which does not flutter in any way, or have any vibratory movement of any type, so that when the elevation of the nozzle has been properly adjusted the web 3 issuing from the compacting gap 9 will very smoothly slide along and be supported by the air cushion. If the elevation of the nozzle is not properly adjusted, then there will -be a fiuttering of the fluid stream and tests have demonstrated that under these conditions the web does not smoothly slide in an unruflied manner along the fluid cushion so that as a result the shortening of the web achieved by the compacting thereof is lost in an undesirable manner.

FIG. 3 schematically illustrates one possible embodiment of a machine which includes the structure of my invention. The illustrated machine includes a table supported by standards 22 and carrying at one end, on suitable brackets 24, a supply roll 26 of the fabric 3 which is to be compacted. The fabric is guided over a guide roll 28 along a pair of steam-furnishing units 30 which in a known way dampen the fabric before it is compacted. A suitable hood 32 is arranged over the steam-furnishing units 30. From the units the web of fabric is guided around the roll 34 carried by suitable standards 36 which are mounted on the table 20, and from the guide roll 34 the web moves to another guide roll 38 supported for rotation between a pair of robust side plates 40 which are arranged in parallel vertical planes and which are fixedly mounted on top of the table 20. It is between these plates 40 that the structure of my invention, shown in FIG. 1, is situated. The pair of parallel side plates 40 are respectively formed with coextensive, aligned guide ways 42 in which the slide member 4 is guided for movement to the right and left, as viewed in FIG. 3, and to each end of the slide member 4 is connected an adjusting structure 44. This adjusting structure 44 can `be hydraulic, pneumatic, mechanical, or electrical, and may include a piston connected by a piston rod at each side of plate 40 to the slide member 4 so as to adjust the position of the latter with fiuid under pressure introduced into the cylinder. However, any rotary nut may engage a screw connected at one end to the slide member 4 so as to advance or retract the latter.

The ends of the roll 1 carry journals received in a pair of bearings 46 Vguided for vertical movement in slide ways 48 formed in the pair of plates 40, respectively, and in this case also suitable adjusting units 50 are carried by the plates 40 and are operatively connected with the bearing elements 46 to adjust the elevation thereof, and these adjusting units 50 taking the form of fluid cylinder and piston assemblies or rotary nuts engaging threaded studs which are fixed to and extend from the bearings 46. An identical pair of adjusting units 52 are connected with bearing plates 54 in which stub shafts at the ends of the roll 2 are journaled, so that the elevation of the roll 2 can also be adjusted. A pair of drive chains 56 and 58 are driven at suitable speed and are connected with sprockets fixed to the stub shafts which are coaxially fixed with the rolls 1 and 2, so that in this way these rolls are rotated.

The container 6 for the fluid under pressure together with the nozzle are supported between the plates 40` in the manner indicated in FIG. 3. The opposed sides of the container 6 are respectively fixed with coaxial tubular extensions 60 which extend through openings 62 respectively formed in the plates 40 and these tubular extensions 60 are carried by the adjusting means of the invention which enables the position of the nozzle 5 to be adjusted. The tubular extension 60 which passes through the opening 62 of the plate 40 which is not visible in FIG. 3 is closed by a suitable plug. The other tubular extension 60 is shown in FIG. 4 fluid-tightly connected with a hose 64 through which air under pressure is supplied to the interior of the container 6. This hose 64 communicates with a tank which receives air under pressure from any suitable compressor or the like. Both of the tubular extensions 60 are slidably received in sleeves 66 which are respectively fixed to the top ends of threaded studs 68 which extend downwardly through rotary nuts 70 carried by brackets 72 which are fixed to the outer side faces of the pair of plates 40 just beneath the openings 62 thereof, as indicated for the opening 62 in FIG. 4. Thus, by turning the nuts 70 it is possible to adjust the elevation of the nozzle 5 and of course it is possible to maintain this nozzle precisely parallel with the compacting gap 9 by turning the nuts 70. In addition, the entire container 6 together with the nozzle 5 can be turned about the common axis of the tubular extensions 60, within the sleeves 66, which carry suitable set screws 74, for example, enabling the nozzle 5 to be fixed at a predetermined adjusted angular position with respect to the common axis of the tubular extensions 60. Thus, the adjusting means shown in FIG. 4, and duplicated at the other end of the container 6, enables the position of the nozzle 5 to be very precisely adjusted.

The web 3 as it slides along the upper part of the box 6 is received by a freely movable endless belt assembly 76 which guides the web to calendering roll 78 supported for rotation by the plates 80 and driven by way of a chain-and-sprocket drive 82. From the calendering roll 78 the web 3 is delivered by guide rolls 79 to a takeup roll 84 supported on a shaft 86 whose ends are guided between a pair of ribs 88 situated at the inner surfaces of a pair of upstanding plates 90 fixedly mounted on the table 20, and this take-up roll is supported Iby a pair of rolls 92 and 94, the roll 92 being driven by a chain-andsprocket assembly 96.

I claim:

1. In an apparatus for continuously and mechanically compacting a flexible web of fibrous material, a rotary rst roll having an exterior surface engaging the web and transporting the latter, and a rotary second roll parallel to said first roll and also having an exterior surface engaging the web, said rolls defining between themselves a compacting gap having an entrance end and a discharge end, and said second roll rotating at a lesser surface speed than said first roll for compacting the web in said gap, a slide member located at that side of said gap where said entrance end thereof is located and having a concave surface of the same curvature as said first roll directed toward but spaced from the exterior surface of said first roll in the region of the entrance end of said gap for cooperating with said first roll to compel the web to enter into said gap at a speed determined by said first roll, and means situated at that side of said gap where said discharge end thereof is located and extending into the space between said rolls closely adjacent to said discharge end of said gap for deflecting the web away from said second roll as it issues from said discharge end of said lgap while guiding said web with substantially no friction away from said first roll as the web issues from said discharge end of said gap, said means preventing the formation of transverse fold lines in said web while retaining therein the effects of the compacting action derived from said rolls, said means including an elongated nozzle extending parallel to the axes of said rolls and directed toward said discharge end of said gap for providing at said discharge end of said gap a fluid under pressure forming a fluid cushion which guides and supports the web as it issues from said discharge end of said gap, said nozzle having a uniform cross section along its entire length, said means including a container for receiving a fluid under pressure and communicating with said nozzle for supplying fluid under pressure thereto, said container having a volume which is sufficiently great, with respect to said nozzle, and including a device upstream of said nozzle to maintain a substantially constant pressure distribution of the fluid along the entire length ofthe nozzle.

2. The combination of claim 1 and wherein said device situated in said container upstream of said nozzle for maintaining constant the pressure of the fluid issuing from the nozzle is a perforated plate through which the uid lows before reaching the nozzle.

References Cited UNITED STATES PATENTS 1,595,478 8/1926 Minton.

2,120,536 6/1938 Woodhead 26-18.6 3,083,435 4/1963 Cohn et al 26-18.6 3,226,796 l/1966 FOX et al 26-l8.6 XR

ROBERT R. MACKEY, Primary Examiner.

U.S. Cl. X.R.

Images