US1992753A - Method and apparatus for continuously conditioning a sheet of fibrous material - Google Patents

Description

Feb. 26, 1935. I KARLSON ET AL 1,992,753

- METHOD AND APPARATUS FOR CONTINUOUSLY CONDITIONING A SHEET OF FIBROUS MATERIAL Filed March 9, 1932 2' Sheets-Sheet 1 lnveIwTors. AlFred F Kcxrlson Thayer Francis byMMi/W v ATTyS.

Feb. 26, 1935. A. F. KARLSON ET AL 1,992,753

METHOD AND APPARATUS FOR CONTINUOUSLY CONDITIONING A SHEET OF FIBROUS MATERIAL I Filed March 9, 1952 2 Sheets-Sheet 2 \HVSHTOTS. AiFved F Korlson Thoyer Francis b wwzzw ATTys.

Patented Feb. 26, 1935 UNITED STATES PATENT OFFICE METHOD AND APPARATUS FOR CONTINU OUSLY CONDITIONING BROUS MATERIAL A SHEET OF FI- Application March 9, 1932, Serial No. 597,856

16 Claims.

This invention relates to improvements in methods and apparatus for'increasing the content of hygroscopic moisture in products composed of hygroscopic materials in the form of sheets, such as textile fabrics, whether woven or felted, paper, or the like.

While especially adapted to the treatment of woven textile fabrics, the scope of the invention includes the treatment of any product finished in continuous sheets, such as cloth, felt, paper, or the like, and hereinafter termed broadly fabric, when it is desired to increase its content of hygroscopic moisture.

In the treatment of certain woolen and worsted textile fabrics, it is common practice to finish the fabric by passing it between heated pressrolls or calenders to produce a smooth, lustrous finish. Contact with the heated rolls causes surrender of a large part of the originally-contained lwgroscopic moisture and appreciably reduces the weight of the fabric per unit of length. There also results a certain harsh condition or feel in the fabric due to the stiff and unyielding condition of the fibres after overdrying.

Certain colored fabrics, and especially colored pile fabrics, often suffer appreciable variation in the shade of their coloration as the result of changes in moisture content when being finished. In such cases it is desirable to condition overdried fabrics to a state of normal moisture content to restore losses in weight; to produce a'natural and soft condition or feel of the material; and to restore the shade of color, when any of these conditions have been adversely affected by loss of normal moisture content. It is necessary, however, to accomplish such conditioning by charging the fabric with moisture that is in the hygroscopic state only, because deposition of palpable moisture on the surface of a finished fabric tends to impair the finish by visible imperfectionssuch as spots or streaks.

It has long been known that a relatively dry fabric exposed to a humid atmosphere will gradually absorb hygroscopic moisture from the water vapor present in the air without damage to its finish, but it is not commercially feasible to conditionfabrics by this method because the necessary time, floor space and labor involve too heavy "an expense. Much effort has therefore been de- 1 voted to the development of methods and apparatus suitable for the reconditioning of fabricby some continuous and economical manufacturing process.

Among the many methods and apparatus heretofore used to this end may be mentioned the following:

The application of steam from a multiplicity of jets to the surface of a strand of moving fabric. Also steaming, accomplished by passing the fabric continuously through an enclosure filled with vapor steam, that is, steam at atmospheric pressure.

While partially successful in restoring moisture content, the use of steam jets has proven undesirable. Particles of condensed moisture are frequently present with the steam and result in damage to the fabric finish. The difficulty of accomplishing uniform distribution of steam over the surface of the fabric results in a streaky and uneven appearance that is highly undesirable.

The liberation of steam in a compartment raises the temperature to undesirable levels and tends to cause condensation of vapor on exposed surfaces of the apparatus and has proven in general to be an undesirable practice.

Another method consists in passing the fabric through an enclosure in which the moving surface of the fabric" is exposed to air charged with spray by atomizers located within the enclosure. Under such conditions the spray does not evaporate with sufficient rapidity to maintain a high degree of saturation of the air of the enclosure that will accomplish rapid transfer of moisture to the fabric and the high capacity that is desired. Furthermore, some of the spray tends to be deposited on the surface of the fabric and the use of such methods has not been attended with success.

Another common method consists in passing the fabric continuously through a compartment in extended form in close parallel juxtaposition to webs or endless belts of felt, or other absorbent materials that are maintained in a moist condition by partial immersion and movement through trays of water which may be artificially heated. The conditioning capacity of an apparatus making use of this method is dependent upon the rate of vaporization from the wetted surfaces which is not sufficiently rapid to maintain a high degree of saturationin the atmosphere such as is essential to rapid absorption of moisture by the fabric, and such methods have therefore proved disappointing in respect to capacity.

' The principal object of the present invention is' to provide a method and'means for conditioning fabrics with hygroscopically absorbed moisture in a continuous process'in a comparatively small space and with greater rapidity, efliciency and economy than has hitherto been attained.

The term hygroscopically absorbed moisture gressive riseinits temperature is herein used to denote exclusively that moisture which is present in a mass of hygroscopic material as the result of absorption of atmospheric moisture present as the vapor of water in the surrounding atmosphere, in contradistinction to palpable moisture such as might be present on the surface of or in such material as the result of deposition of particles of spray thereon or as the result of immersion in or contact with water in a fluid state.

The present invention avoids all possibility of damage to the finish of the fabric by contact with either steam or spray. While being treated we provide for the exposure of the fabric to air conditioned to a high and controllable degree of humidity, and to a moderate and controllable temperature, from which conditioned'air; all free moisture or spray effectively is excluded.

The process of absorption of hygroscopic moisture by a mass of hygroscopic material from vapor present in the surrounding air is attended by considerable and appreciable liberation of heat and consequent rise in the temperature of the surrounding air due to the absorption of the heat thus liberated.

The major component of this liberated heat is due to the latent heat liberated by the condensation of that amount of moisture which is converted from the state of vapor present in the atmosphere to that of hygroscopic moisture in the material during the process of absorption.

Research by eminent and competent textile experts has disclosed the fact that in the case of certain textile fibres, and notably in the case of wool, the process of absorption of moisture from the atmosphere is attended by the liberation of an amount of heat that measurably exceeds the latent heat attributable to condensation of vapor alone, and this additional component of the liberated heat has been termed the heat of wetting. In the case of wool when conditioned from aninitial regain of 3% to a final regain of 11% as against its bone dry weight it has been demonstrated that of the total heat liberated.

75% was attributable to the latent heat of condensation and 25% to the heat of wetting.

It is therefore evident that the amount of heat liberated during the conditioning of a fabric by exposure to a moist atmosphere will inevitably and materially increase the temperature of the surrounding air as a result of absorption by the air of the liberated heat.

When the material in the fabric being treated has an initial temperature higher than that of the air, as is frequently the case, there is a corresponding interchange of heat, tending to further increase the air temperature.

We have found that the rise in air temperature 'resulting from" either of these causes or from any combination thereof is considerable and that it appreciably retards the transfer of moisture from the air to the material in a process or apparatus of the class described because of the progressive fall the-relativehumidity of the conditioned air passing through the chamber due to'the pro In methdds andj app'afatus hitherto used for through an ncloseds'pace or 'compartinjentconan aade'quat'efprovision has hitherto 'becn inrade forthe' absorption and removalqof heat liberated during iho process of transfer.

ainirig emf-into "whichLmoisture-is introduced as- .spray- 'or vaporsu'p'plied y variousrhe'a'ns comontain'ed' within the compartment itself While currents of air have been used in some instances for the purpose of supplying water spray or vapor to such compartments, such provisions for air circulation are not adequate for the sufficiently rapid removal of liberated heat nor for a sufficiently rapid and voluminous circulation of air to carry an adequate supply of water vapor.

We have found that a current of air traversing a compartment of the type above described experiences a progressive rise in temperature by virtue of heat liberated by the transfer of moisture from the air to the fabric, and that as the air temperature rises the consequent fall in its relative humidity is further augmented by the loss of water vapor that has meanwhile been transferred from the air to the fabric. A relatively small volume of air with its relatively small total content of water vapor surrenders most of its available moisture to the fabric before it has traversed more than a fraction of the space within the compartment. It is because of the conditions just described that the total capacity for transfer of moisture to the fabric in apparaand unsatisfactory.

The rapidity withwhich the hygroscopic material absorbs moisture from the atmosphere to which it is exposed is known to decrease as the moisture content of the material rises and as the humidity of the surrounding air decreases until transfer ceases altogether when that condition is reached which is known as hygroscopic-equilibrium between the moisture content of the material and the humidity of the surrounding air. When the volume of air is small, even though it be saturated, the air is so quickly exhausted of its moisture by the absorption of the fabric that the differential relationship between the humidity of the air and the moisture content of the material, which may be termed the hygroscopic head is effective in producing absorption only during a part of the period of exposure and the total absorption is correspondingly small;

By increasing the volume of air and the corresponding vapor available for absorption the exhaustion of moisture is delayed and the hygroscopic head becomes effective throughout the period of exposure with a corresponding increase in the rate of absorption and in the total absorp tion.

If the volume of air be sufficient to cause hygroscopic absorption of moisture throughout the period of exposure any further increase in the volume of air or the degree of initial saturation of the air will cause a corresponding increase in the effective hygroscopic head and in the rate of absorption and the total thereof.

The rate at which moisture is transferred under the conditions prevailing in the use of our invention is therefore a function of the differential relation between the humidity of the air and the moisture content of the material exposed thereto, and this relationship holds true of all parts of the fabric during the period of exposure to thej moving current of air. I

It is characteristic of the method 'a'nd apparatus of the present invention thatthe rate of absorption is regiilatedby correlatingthe volume of theair current to the initial. humiditythereof to determine the 'fl'na'l'mois'tiire content of: the

fabric which is thus controlled at will by varythe humidity of the air as it progressively falls the moisture content during the period of exposure and the moisture content of the fabric as it progressively increases during the same period.

It is therefore clear that the rate ofabsorption may be effectively controlled either by using saturated air and varying the volume of the air current, or by using partiallysaturated air in ample volume and varying the degree of saturation. Either of the above expedients causes the desired variation in the effective humidity of the air and the differential relation between it and of the fabric exposed thereto. v

The present invention is clearly distinguished from the prior practice in the art in that we provide two separate and distinct steps in the process, first, the conditioning of the air to any desired degree of saturation with the vapor of water with the exclusion of all free moisture or spray, and, second, subsequent exposure of the fabric to the action of the conditioned air, the two steps being performed serially and continuously.

The invention broadly comprises continuously causing an extended web of fabric to travel in an enveloping current of air preconditioned with moisture as vapor only preferably flowing counter to the travel of the fabric and increasing the moisture content of the fabric with moisture progressively absorbed from the current of preconditioned air.

More specifically the method comprises continuously moving a web of the fabric in extended form within an enveloping current of air preconditioned with moisture as vapor only in controllable volume and correlating the volume of air to the speed of the fabric to effect progressive absorption of moisture by said fabric to a predetermined value of moisture content.

Preferably the enveloping current of air is preconditioned with moisture to substantial saturation and the volume of the current of air so correlated to the speed of the web of fabric as to effect progressive absorption of moisture by the fabric from the air while in contact therewith at a substantially uniform rate.

The amount of hygroscopic moisture absorbed by the fabric may be controlled or determined if the fabric is moving in extended form at a uniform rate longitudinally of the path of the current of conditioned air, either by varying the volume of the conditioned air or by varying the vapor content of the preconditioned air, or by providing a constant and continuous current of preconditioned air and varying the rate of travel of the web of fabric.

The method further comprises the finishing and conditioning of fabric ina continuous process which comprises conditioning a supply of air with moisture as vapor only, subjecting a continuously moving web of the fabric progressively to heat and compression, or'to heat while under transverse compression, and then to the hygroscopic effect thereupon of atmospheric moisture by conducting the fabric in longitudinally .extended form through and within the path of a current of said conditioned air.

The invention further comprises determining the resultant moisture content of the fabric by controlling the rate of flow of the conditioned air, or by otherwise so correlating the speed of the fabric and the volume of air as to determine the resultant moisture content of thefabric-as aforesaid. v p" In the apparatus for performing the process two agencies are organized in co-operative combination. One agency is a complete air-conditioning. apparatus for generating acurrent of air and charging it with the vapor only ofwater to any desired degree of saturation at a predetermined temperature, and in an ample volume, that is limited only by the capacity of the airconditioning apparatus itself. The other agency is a conditioning chamber that is traversed continuously by the fabric in extended form, while exposed to the hygroscopic effect of an envelopingcurrent of conditioned air supplied thereto from the air-conditioning apparatus and which is caused to pass through the compartment and over the surfaces of the fabric at relatively high velocity in any desired volume within the capacity of the air-conditioning apparatus.

An important characteristic of the present invention is the provision'bf means whereby the entire space within the conditioning compartment may be effectively utilized for the transfer of moisture from the air to be moving fabric at a substantially uniform rate, thus attaining a high efficiency of transfer and a correspondingly high transfer capacity for the compartment as a whole. We accomplish this result by providing such an ample volume of conditioned air as is sufficient to absorb and carry away the liberated heat and to limit the rise in air temperature to a moderate value, while at the same time providing such correspondingly liberal supply of vapor only as will limit the fall in relative humidity to substantially that degree which is consequent upon the loss of water vapor from the air within the enclosure.

We also preferably provide means for the guiding of the current of conditioned air in a path such as to cause it to envelop the fabric throughtype above described through which the fabric is continuously conducted in extended form in one general direction, while the current of conditioned air is passed through the compartment in intimate contact with the traveling fabric in a predetermined path preferably in a direction that is opposite in general direction to the movement of the fabric.

Desirably the current of air enters the compartment at a point immediately adjoining that at which the treated fabric leaves the compartment, and leaves the compartment at a point close to the point where the fabric to be treated enters the compartment.

It is known that the rate at which moisture will be transferred to a hygroscopic material from the atmosphere to which it is exposed varies with the difference between the vapor pressures due respectively to the vapor present in the atmosphere and to the moisture present in the material, which difference, for convenience, is herein termed the hygroscopic head.

Suitable apparatus for performing the process above described is illustrated in the accompanying drawings, in which, i

Fig. l isa diagrammatic view in side elevation;

a casing,'of any desirable 4 material, of rectangular form, having vertical sides 1 and 2 and ends 3 and 4 extending upwardly from a suitable base or from the floor, and preferably provided with suitable supporting legs 5. A top 6, which is integral with or secured to the sides and ends, provides a closed chamber into which preconditioned air is introduced and caused to flow through the chamber in a predetermined path.

The apparatus for preconditioning the air is located externally of the chamber and may be either a self-contained unit 7 as diagrammatically shown or an equivalent assembly operable to generatea current of air and precondition the same to any desired degree of humidity or saturation with the vapor of water only. Such selfcontained units are available in the open market and well known to the art as unit air conditioners and are exemplified by the construction disclosed in Patent No. 1,743,668, granted January 14, 1930 to William B. Hodge. Such units or assemblies comprise a chamber or compartment containing spraying means operable to saturate a current of air with water vapor, eliminating means operable to extract all free moisture from the air after treatment, and a blower or similar means operable to generate the current of air to be conditioned in passing through said chamber. Regulating means for determining the degree of saturation of the conditioned air and heating means operable to determine the temperature of the spray water are common and desirable provisions in such apparatus and any assembly of apparatus operable to perform the. above functions is adaptable for the purposes set forth and within the scope of our invention.

The current of air generated and conditioned by the air conditioning apparatus 7 passes through an eliminator 75c which extracts all free moisture from the air and is thence conducted through a pipe or conduit 8 and introduced into the conditioning chamber near the upper portion of the end opposite to that through which the traveling fabric is conducted into the chamber. Suitable means are provided for the purpose of regulating the volume of conditioned air delivered from the external conditioning apparatus '7 to the conditioning chamber such as a valve or damper located in the conduit 8. Any other suitable means may be used for the same purpose such as means for varying the speed of the fan that moves the current of air.

Water is centrifugally atomized and intimately mixed with the stream of air, thereby humiditying the air. All surplus spray over and above that required to produce the desired degree of humidity in the air is extracted by an eliminating device, and the air is then delivered from the top of the humidifier to the conduit 8. The humidified air may be heated if desired before being delivered to the conduit. A fan and its motor for propelling the air upwardly are positioned beneath the atomizing device and propel the air through a central passage in an annular drip 'andwater supply pan. Positioned centrally of this passage and extending upwardly thereabove is' a water-containing pan which, with the inner edge of the drip and water supply pan, forms an annular passage for the air. Water is continuously drawn upwardly from the lower part of this pan by centrifugal action and sprayed into a thin film and projectedagainst a corrugate'd'disintegrated surfacdadiacent the inner upper edge of the pan and is thereby broken-into a finemist uniformly fdistr of the pan and in position to be taken up by the upwardly passing air. Any particles too large to remain suspended in the air will fall back into the pan or into the drip and water supply tank. The supply of water may be so controlled as to bring the air to the required degree of humidity or v saturation with moisture in a state of vapor only.

Means are provided for controlling the rate of vaporization to obtain any desired degree of humidity and means are also provided for controlling the temperature of the air delivered from the humidifier as fully appears from the disclosure of the patent aforesaid.

It is contemplated in the present invention that the total cubical content or fabric-holding 'capacity of the compartment and the capacity of the air conditioning unit shall both be so determined as to accomplish'the conditioning of the fabric with hygroscopic moisture to the desired predetermined maximum degree and at the rate desired. It is also contemplated to determine the degree to which the fabric is conditioned atany desired value less than the predetermined maximum, by varying the rate of circulation of the current of conditioned air, or by varying the degree of saturation of the conditioned air 'by means of adjustments of a humidifying device as described in the aforesaid patent, or by means hereinafter to be described.

In the apparatus illustrated herein special means are provided for determining the path pursued by the conditioned air when circulating over the exposed surfaces of the fabric while the fabric passes through the compartment, the arrangement being such that the web of fabric is enveloped by the current of air so that all surfaces of the fabric are swept by the current of air at appreciable velocities, thereby avoiding stagnation and retarded transfer in any part of the compartment. This is accomplished by providing a chamber with a series of vertical partitions 10 and 11 extending alternately downwardly from the top and upwardly from the bottom terminating short of the depth thereof and dividing the space within the chamber into vertical parallel compartments connected in series to constitute a continuous passage through the chamber. The conduit 8 leads from the humidifier '7 into the upper end of the compartment 12 and the conditioned air passes downwardly through the compartment 12 around the lower end of the parti tion 10, thence upwardly through the compartment 13 over the upper end of the partition 11 and downwardly through the compartment 14 and from the lower end of this compartment preferably through a conduit 15 into the lower or base portion of the humidifier 7.

As illustrated in the accompanying drawings the web of fabric 16 passes beneath a guide roll 17 in an opening in the end wall 4 of the compartment l4, thence alternately upwardly and downwardly over upper and lower series of rolls 18 and 19 in the several compartments and is finally delivered near the lower end of the compartment 12 beneath a'roll 20. The upper series of guide rolls 18 desirably are provided with suit able gearing 21 and means for actuating the same to cause any desired rate of movement of the, web of fabric in By reason of this construction the'fabridis caused to pass through the several "compartments in substantially parallel and preferably vertical convolutions longitudinally of the compartments I and is thus adapted to expose tothe conditioned ii I than the width of the fabric.

air the greatest possible yardage of fabric containable within the dimensions of the compartment.

A further important feature of the invention consists in providing means for confining the flow of conditioned air into the several compartments to a path narrower than the width of the fabric, thereby to cause the air to flow only into the open spaces between alternate convolutions of the web and thereafter, by virtue of the pressure imposed upon the air, to flow through said web or around the edges thereof into the adjoining spaces betwen the convolutions of the web. This arrangement tends to produce a slight but important flow of conditioned air through the interstices of the fabric from one side to the other, and tends further to improve the efficiency and rapidity of moisture transfer from the air to the fabric.

In the construction illustrated the current of conditioned air is forced from the air conditioner 7 through the pipe 8 into the upper portion 22 of the compartment 12 above the upper guide rolls 18 over which the fabric is led. Desirably a series of bailies 23, extending transversely of the upper portion 22 of the compartment, are suitably arranged to direct the air vertically downwardly through the compartment 12. End baflies or par-' titions 24 and 25 extend from the sides of the compartment inwardly over the respective edges of the fabric 16 a suflicient distance to cause the air to be directed downwardly into the open spaces between the adjacent convolutions of the fabric,.so that the pressure of theair causes it to pass first over one side of the fabric and either through the interstices of the fabric or around the edges of the fabric into the adjacent spaces between the convolutions of the web. The lower end of the compartment 12is likewise provided with baflies or partitions 26 and 27 extending from the ends of the compartment inwardly beyond the edges of the compartment which confines the outlet of the compartment to an area of less width Likewise the compartments l3 and 14 are provided with baflies or partitions similar to the upper bafiles 24 and 25 and lower baifles 26 and 27, so that the current of air flowing through the respective compartments is confined in a similar manner at the entrance and exit of the compartments to a width less than that of the web of fabric.

Desirably the air is conducted from the lower end of the compartment 14 through a return pipe 15 to the air conditioner 7 in the manner here- "tofore described to provide a continuous re-circulation of the current of conditioned air through the apparatus as a whole, thereby to conserve moisture.

One of the main purposes of the invention is to provide a supply of conditioned air for the humidifying chamber of sufiicient volume for the rapid and effective absorption and removal of liberated heat and with a sufiicient total content of water vapor to insure the addition of the desired amount of hygroscopic moisture to the fabric passing through the compartment. Hence it is essential, first, that the air conditioner should have capacity for moving a predetermined and necessary maximum volume of conditioned air and for raising the vapor content of the air to and maintaining the same at the desired degree of humidity or saturation at the desired temperaturefhe invention also contemplates the provision of means for limiting the value of hygroscopic moisture finally acquired by the fabric by virtue the fabric. This is accomplished by providing suitable means for driving the guide rollers 18 and 19 at-such speed as to cause the fabric to travel at a predetermined rate correlated to the fiow of the conditioned air, and thereby to determine the hygroscopic condition acquired by the fabric during its passage through the chamber. (2) By controlling the relative humidity of the conditioned air at a given temperature at which it is delivered to the conditioning chamber. This is accomplished by suitable adjustments of the air-conditioning apparatus in the manner disclosed in the patent to Hodge aforesaid, or by equivalent means. (3) By controlling the rate at which the conditioned air is supplied to and circulated. through the compartment. This is accomplished by providing the pipe 8, which leads from the air-conditioner 7 to the conditioning chamber, with a suitable valve such as a butterfly valve 28 having a handle member 29 by which it may be adjusted to control the volume of air delivered from the air-conditioner to the conditioning chamber;

While it is true that the temperature at which the conditioned air is saturated has a certain effect upon the transfer of moisture, that effect is relatively small as compared with the three principal conditions above specified. y

In the preferred operation of the apparatus it is usually convenient to maintain a constant linear speed for the fabric and to maintain a condition of saturation in the air leaving the airconditioner at a constant temperature by means of a thermostat actuated by the temperature of the spray water in the air-conditioner controlling the supply of heat to the air-conditioner. These two conditions having thus been fixed, the rate of air supplied to the conditioning compartment is controlled by adjustment of the valve 28 in such a manner as to fix the rate of air supply at that 'value which will limit the hygroscopic moisture condition attained by the fabric to the value desired.

It is found in practice that by properly correlating the volume of air preconditioned with moisture as vapor only to substantial saturation to the rate of travel of the fabric, progressive absorption of moisture from the air by the fabric while in contact therewith will be produced at a substantially uniform rate throughout the passage of the fabric through the conditioning chamber.

It will be clear to those skilled in the art that the actual effect of the preferred arrangement above described is adjustably to control the volume of conditioned air and the quantity of atmospheric moisture carried thereby in such mannor as to provide the desired hygroscopic effect upon the fabric during its exposure within ,the compartment.

It will also be clear to those skilled in the art that of the three controllable conditions above specified any two may be fixed at a constant value arrangement without departing from the spirit or scope of the invention.

A further object of the invention is to provide a process and apparatus for finishing fabric which comprises, first, subjecting a moving web of the fabric to heat and compression or to heat while under transverse compression, and then to the hygroscopic effect of atmospheric moisture by conducting the fabric in longitudinally extended form through and within the path of the current of conditioned air flowing counter to the travel of said fabric. This is accomplished in the present invention by providing a pair of heated rolls 30 and 31 between which the web of fabric 16 is passed prior to its introduction into the conditioning chamber. The rolls 30 and 31 may be driven at uniform speed, or one of them may be driven at a higher speed than the other to subject the web of fabric to friction as well as compression.

The web of fabric desirably is delivered from the heated rolls 30 and 31 upon a preferably curved support 32 where it is permitted to accumulate in folds and to remain for a short time exposed to the air to permit a substantial cooling of the fabric. The web 16 is then led beneath the roll 1'7 into the conditioning chamber and over the upper and lower guide rolls 18 and 19 thereof in the manner'aforesaid. During its passage through the conditioning chamber it is caused to travel in extended form longitudinally of the flow of the conditioned air which is supplied from the air conditioner '7 and controlled in the manner above described.

By reason of the present invention, therefore, the normal hygroscopic moisture content of the fabric is restored and the harshcondition or feel of the fabric, due to stiff and unyielding condition of the fibres due to overdrying, is overcome.

By reason of the exposure of the fabric to air containing moisture as vapor only during its passage through the conditioning chamber, the resultant absorption of moisture by the fabric is uniform throughout the web and any variation of color in the finish of the fabric is avoided.

It will be understood that the apparatus for performing the method herein shown and described is illustrative only, and that various changes in form, construction and arrangement of parts may be made within the spirit and. scope of the claims. It will also be understood that a single air conditioner of suitable capacity may be employed to supply moisture in a state of vapor only to a plurality of conditioning chambers in which the webs of fabric may be treated in the manner herein described.

; Having thus described the invention, what is claimed as new, and desired to be secured by Letters Patent, is:

'1. Apparatus for conditioning fabric with hygroscopically absorbed moisture in a continuous process comprising a chamber, means for conducting a web of fabric in extended form through said chamber at a uniform rate, means external to said chamber for'preconditioning a body of air with moisture as vaporonly, means for causing a current thereof to flow continuously through said chamber in intimate contact with said fabric in a general direction counter to the direction of movement of the fabric, the volume of the current of air and the moisture content thereof being sufficient to cause said fabric to absorb moisture hygroscopically from said air throughout the path of exposure and to causethe vapor initially available for said absorption to be progressively surrendered by said air in accordance with the volume thereof, and adjustable means operable to regulate the volume of air and the vapor content thereof to determine the rate of said absorption and the final moisture content of said fabric.

2. Apparatus for conditioning fabric with hygroscopically absorbed, moisture in a'continuous process comprising a chamber, means for conducting a web of fabric in extended form through said chamber at a uniform rate, means external to said chamber for preconditioning a body of air with moisture as vapor only, means for causing a current thereof of sufficient volume to flow continuously through said chamber in intimate contact with said fabric, to cause said fabric to absorb moisture hygroscopically from said air throughout the path of exposure and to cause the vapor initially available for said absorption to be progressively surrendered by saidair in accordance with the volume thereof, and adjustable means operable to regulate the volume of said air and thereby to determine the rate of said absorption and the final moisture content absorbed by said fabric.

3. Apparatus for conditioning fabric with hygroscopically absorbed moisture in a continuous process comprising a chamber, means for conducting a web a fabric in extended form through said chamber at a uniform rate, means external to said chamber for preconditioning a body of air with moisture as vapor only, means for causing a constant current thereof of such volume to flow continuously through said chamber in intimate contact with said fabric, as to cause said fabric to absorb moisture hygroscopically from said air in accordance with the vapor therein available for such absorption and adjustable means operable to regulate the supply of vapor I to said body of air thereby to determine the resultant moisture content of said fabric.

4. Apparatus for conditioning fabric with hygroscopic moisture in a continuous process comprising a chamber having vertical partitions dividing the space within the chamber into verticalparallel compartments, means for guiding the traveling web of fabric serially through said compartments in parallel convolutions within and longitudinally of the respective compartments, means external of said chamber for conditioning a current of air witlrmoisture as vapor only, and means for causing said current of air to flow through said compartments, and means at the entrance to each compartment for directing the flow of said conditioned air into a path narrower than the width of the fabric thereby to cause said air to flow only into the open spaces between alternate convolutions of said web and thereafter to flow through said web or around the edges thereof intothe adjacent spaces between the convolutions of said web.

5. Apparatus for conditioning fabric with hygroscopic moisture in a continuous process comprising a chamber having vertical partitions dividing the space within the chamber into vertical parallel compartments, means for guiding the traveling web of fabric serially through said compartments in parallel convolutions within and longitudinally of the respective compartments,

means external of said chamber for conditioning flow only into the open spaces between alternate convolutions of said web and thereafter to flow through said web or around the edges thereof into the adjoining spaces between the convolutions of said web.

6. Apparatus for conditioning fabric with hygroscopic moisture in a continuous process comprising a chamber having vertical partitions extending alternately downwardly from the top and upwardly from the bottom of said chamber, terminating short of the depth thereof and dividing the space within said chamber into vertical parallel compartments interconnected in series to constitute a continuous passage through said chamber, means for guiding the travelling web of fabric through said passage in parallel convolutions within and longitudinally of the respective compartments, means external to said chamber for conditioning a current of air with moisture as vapor only, means for maintaining continuous circulation of said current of air from said air-conditioning means to and through said passage in a direction counter to the travel of said fabric therethroughand from said passage to and through said air-conditioning means, andmeans at the entrance to each compartment for directing the flow of said conditioned air into a path narrower than the width of the fabric thereby to cause said air to flow only into the open spaces between alternate convolutions of said web and thereafter to flow through said web or around the edges thereof into the adjoining spaces between the convolutions of said web. 7. The method of conditioning fabric in a continuous process which comprises exposing the fabric in the form of an extended web traveling at a uniform rate in a path of predetermined length to the hygroscopic effect of a continuous confined current of air preconditioned with moisture as vapor only and enveloping said fabric throughout the path of exposure, the current of preconditioned air being of ample volume to cause the fabric progressively to absorb moisture hygroscopically from said current of air throughout the path of exposure and varying the rate of said absorption by adjustably intercorrelating the volume of said air current, the initial humidity thereof, and the period of envelopment of said web to regulate the resultant moisture content of the fabric.

8. The method of conditioning fabric in a continuous process which comprises exposing the fabric in the form of an extended web traveling at a uniform rate in a path of predetermined length to the hygroscopic effect of a continuous confined current of air preconditioned with moisture as vapor only to substantial saturation and enveloping said fabric throughout the, path of exposure, the current of preconditioned air being of ample volume to cause the fabric progressively to absorb moisture hygroscopically from .said current of air throughout the path of extinuous process which comprises exposing the" fabric in the form of an extended web traveling.

at a uniform rate in a path of predetermined length to the hygroscopic effect of a continuous confined current of air of constant volume preconditioned with moisture as vapor only and enveloping said fabric throughout the path of exposure, the current of preconditioned air being of ample volume to cause the fabric progressively to absorb moisture hygroscopically from said current of air throughout the path of exposure -and determining the resultant moisture content of the fabric by regulating the initial humidity of said current of conditioned air.

10. The method of conditioning fabric in a continuous process which comprises exposing the fabric in the form of an extended web traveling at a uniform rate in a path of predetermined length to the hygroscopic effect of a continuous confined enveloping current of air preconditioned with moisture as vapor only thereby to maintain a hygroscopic head effective to condition said fabric gradually and progressivelyv throughout the path of exposure thereof and varying said hygroscopic head by intercorrelating the volume of said air current, initial humidity thereof and the period of envelopment of said web to regulate the resultant moisture content of the fabric.

11. The method of conditioning fabric in a continuous process which comprises exposing the fabric in the form of an extended web traveling at a uniform rate in a path of predetermined length to the hygroscopic effect of a continuous confined enveloping current of air preconditioned with moisture as vapor only to substantial saturation thereby to maintain a hygroscopic head effective to condition said fabric gradually and progressively throughout the path of exposure thereof and varying said hygroscopic head by regulating the volume of said current of air to produce a predetermined resultant moisture content.

12. The method of conditioning fabric in a continuous process which comprises exposing the fabric in the form of an extended web traveling at a uniform rate in a path of predetermined length to the hygroscopic effect of a continuous confined enveloping current of air of constant volume preconditioned with moisture as vapor only thereby to maintain a hygroscopic head effective to condition said fabric gradually and progressively throughout the path of exposure thereof and varying said hygroscopic head by varying the initial humidity of said current of air to determine the resultant, moisture. content of the fabric.

13. The method of conditioning fabric in a continuous process which comprises exposing the fabric in the form of an extended web traveling at a uniform rate in a path of predetermined length to the hygroscopic effect of a continuous confined enveloping current of air traveling in a direction .counter to the general direction of movement of said fabric and preconditioned with moisture as vapor only to substantial saturation,

compensating the progressive rise,in tempera heat and a sufiiciency of moisture as vapor only to maintain a hygroscopic head effective to condition said fabric uniformly throughout the exposed length, and determining the resultant moisture content of the conditioned fabric by regulating the volume of said preconditioned air.

14. The method of conditioning fabric in a continuous process which comprises exposing the fabric in the form of an extended web travelin in a path of predetermined length to a continuously circulating confined enveloping current of air, continuously preconditioning said current of air with moisture as vapor only before entering the path in which it envelops said web, thereby causing the fabric progressively to absorb moisture hygroscopically from said current of air throughout the path of exposure and varying the rate of said absorption by adjustably intercorrelating the volume of said air current, the supply of humidity thereto, and the period of envelopment of said web to regulate the resultant moisture content of the fabric.

15. The method of conditioning fabric in a continuous process which comprises exposing the fabric in the form of an extended web traveling at a uniform rate in a path of predetermined length to a continuously circulating confined enveloping current of air, continuously preconditioning said current of air with moisture as vapor only before entering the path in which it envelops said web, thereby causing the fabric progressively to absorb moisture hygroscopically from said current of air throughout the path of exposure and determining the resultant moisture content of the fabric by regulating the volume of the current of air.

16. The method of conditioning fabric in a' continuous process which comprises exposing the fabric in the form of an extended web traveling at a uniform rate in a path of predetermined length to a continuously circulating confined enveloping current of air, continuously preconditioning said current of air with moisture as vapor only before entering the path in which it envelops said web, thereby causing the fabric progressively to absorb moisture hygroscopically from said current of air throughout the path of exposure and determining the resultant moisture content of the fabric by regulating the amount of moisture supplied to said air current.

ALFRED F. KARLSON. THAYER FRANCIS.

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