US2202045A - Method of and apparatus for drying fabric - Google Patents

Description

May 28, 1940.

S. COHN ET AL METHOD OF AND APPARATUS FOR DRYING FABRIC 4 Sheets-Sheet 1 in A/l Filed Oct. 50, 1936 lNV ToRS May 28, 1940.

s. COHN :1- AL METHOD OF AND APPARATUS FOR DRYING FABRIC Filed Oct. 30, 1936 4 Sheets- Sheet 2 I IV NT Rs y-kq ATTO R N EY E May 28, 1940.

s. cor-m ET AL METHOD OF AND APPARATUS FOR DRYING FABRIC Filed Qct. so, 1936 4 Sheets-Sheet s f t llli ATTORNEY May 28, 1940. v HN HAL 2,202,045

METHOD QF.AND AFPARATUS FOR DRYING FABRIC Filed Oct. 30, 1936 4 Sheets-Shet 4 p E i If 80 h g q 6/ Patented May 28, 1940 METHOD OF AND APPARATUS FOR DRYING FABRIC Samuel Oohn, New York, and Jules G. Walter, Ridgewood, N. Y., assignors to Samcoe Holding Corporation, New York, N. Y., a corporation of New York Application October 30, 1936, Serial No. 108,318

. 9 Claims.

The present application is, in part, a division of our co-pending application Serial No. 691,522, filed the 29th day ofSeptember, 1933, United States Letters Patent No. 2,109,469. In said copending application there is shown, described and claimed a method and apparatus for treating fabric in long strips, or in continuous lengths, for the purpose of subjecting the fabric to different operations such as chemical treatments, merw cerizing, increasing or decreasing of gloss, drying, finishing, and various other co-related steps, and while the process and apparatus of that application may be used for various kinds of fabrics, it may be successfully used in handling tubular, knitted goods, especially rayon, which latter is very sensitive and subject to impairment if the process does not protect the fabric against injury. The present case is intended to cover the method of drying fabric, whether of knitted, tubular goods, or other fabrics, although certain features of the machine and method are especially designed to successfully treat tubular knitted goods which are more dlflicult to treat than woven and other kinds of fabrics. The present case is intended to cover a method and apparatus for drying fabric in any lengths and for maintaining the desired condition in the fabric while it is undergoing the drying operation in a drying chamber, and it is especially intended to control so the movement of different portions of the fabric in the drying chamber according to the condition of the fabric at different portions thereof throughout the drying chamber and to control the propulsion of the fabric by automatic means which are themselves controlled by the tautness or looseness of the fabric at different places in the drying chamber. By controlling. the movement of the fabric more or less locally in the different portions of the chamber, it is possible to avoid on the one hand too much tension in the fabric, and on the other hand to prevent excess local accumulation of the fabric beyond that desired.

Some fabrics, in the course of treatment, may require a slight tension or slight tautness while being subjected to the current of heated air for extracting moisture, whereas in other cases it is desirable to maintain a slight looseness in the fabric, and with the present apparatus and under the present method accurate control may be accomplished in a manner to meet all conditions for treatment of fabrics of different character.

In the handling of knitted, tubular fabric, the operation is especially delicate because such fabrics are made either of a single yarn or a very as limited number of ,varns constructed, as is well known, in a series of interlocking loops, and such fabrics, when stretched lengthwise, have a tendency to draw in or become narrow unless restrained; and, conversely, when such fabrics are stretched or distended laterally they have a tend- 5 ency to shorten in-length unless restrained, and because of these characteristics it is necessary to control the movement or propulsion of the fabric, especially where there are a great many runs of superposed lengths in the drying chamber, by sensitive and delicate means which will on the one hand propel the fabric without creating any undue local stresses and at the same time prevent excessive accumulation of the fabric in its course of travel.

Under the present method and with the present apparatus the control is automatic and is effected through the condition of the fabric itself. By providing a multiple of controls disposed in the manner hereinafter described, each run of fabric or several adjacent runs of fabric may be independently controlled so that if the fabric should tend to tighten locally the condition may be remedied locally, and likewise if there is a local accumulation of fabric it may be taken up locally or the propulsion of the fabric may be modified to avoid excessive local accumulation.

Under the present method and apparatusall of these conditions may be successively met so that the fabric, after undergoing the complete drying operation, may be brought out of the drying chamber, either completely dry or with any desired percentage of moisture therein, and in the case of knitted, tubular fabrics, it is possible to deliver the fabric from the apparatus having a uniform width and having a given length per pound and treated uniformly throughout the length of the fabric.

Another object of our invention is to provide an equalizer for automatically controlling the fabric to cause it; to move in a straight line through the drying apparatus and to prevent it from shifting laterally to an undesirable degree on the propelling rollers so that the median line of the fabric will travel substantially in a straight 5 line while passing through the drying chamber. While this branch of our invention may be used on other types of machines for handling long strips of fabric, it is especially advantageous in the present machine to maintain the median line of the fabric in a straight line. where the fabric, in passing through the drying chamber, is caused to travel in a multiplicity of superposed runs, we prefer to provide a rectifying device adjacent each propelling roller, or approximately. one for each second run of the fabric in the drying chamber.

Each rectifying device is automatic in the sense that it is operated and controlled by the fabric itself, and if the fabric has a tendency to shift laterally adjacent a propelling roller, the rectifier automatically and gently restores the fabric to its correct course by producing a counterlead.

The present rectifier, in addition to maintaining the fabric in a straight line, also serves to remove wrinkles or creases which tend to form Where fabric is passed reversely around a number of rollers. The present rectifier is simple in construction and very inexpensive to make, which permits a number of them to be used in a single drying chamber. The rectifiers produce rapid rectification of the course of travel of the fabric when the latter begins to leave the correct median line.

The present invention also involves novel means for driving the various propelling rollers which propel the fabric, together with means controlled automatically by the looseness or tautness f the fabric itself, for modifying the action of the driving means and the various fabric propelling rollers, and while we have shown in the present case a belt arrangement for driving the various fabric propelling rollers, it is to be understood that if desired the clutch device shown in our Patent No. 2,109,469, and also shown in our co-pending application Serial No. 160,980, may be used for operating the fabric propelling rollers within the scope of the method described herein, and within the scope of the broader claims on the apparatus. The particular form of drive shown and described herein is itself covered in the aforesaid pending application Serial No. 160,980. Any other form of drive may be used.

Different fabrics stretch differently due to their different weightsper yard, to the differences in their structure, and to the moisture content, and the present apparatus is adapted to handle all fabrics under all conditions and to control or limit the longitudinal stretch of any kind of fabric and at the same time propelling the fabric through the drying chamber.

Other features and advantages of our invention will be set forth in detail in the following detailed description of our invention.

In the drawings forming part of this application:

Figure 1 is a side elevation of an apparatus embodying our invention in a preferred form,

Figure 2 is a plan view thereof,

Figure 3 is a sectional view taken on the line 3-3 of Figure 2,

Figure 4 is an enlarged elevation of the device for driving the fabric propelling rollers,

Figure 5 is a cross sectional view showing one of the fabric propelling rollers, and the automatic means for controlling its operation,

Figure 6 is a sectional view taken on the line 66 of Figure 5,

Figure 7 is a plan view of one of the rectifiers,

Figure 8 is an elevation of one of the rectifier rollers with parts shown broken away to show the interior construction,-

Figure 9 is a sectional view taken on the line 9-9 of Figure 7,

Figure 10 is a sectional view taken on the line Ill-l0 of Figure '7,

Figure 11 is a sectional view taken on the line ll-ll of Figure '7, and

Figure 12 is a perspective view of one of the fabric propelling rollers, the return guide rollers, and one of the rectifying devices.

Figure 13 is a detailed sectional view of the air trap for preventing the heated air from passing through the. horizontal dividing walls.

The heating chamber is preferably constructed of such shape and proportions as to provide for a number of long horizontal runs of the fabric, although we do not wish to exclude from the scope of our invention a chamber in which the fabric is disposed in long vertical runs. In the drawings we have shown the drying chamber as consisting of a bottom wall I, a top wall 2 an end wall 3, an opposite end wall 4 together with side walls 5 all disposed in substantially rectangular formation, and these walls are preferably made of metal to avoid fire hazard. The chamber provided by this structure is subdivided in the following manner:

First, there is preferably a wall 6 spaced from the end wall 4 to provide a vertical air flue I to permit passage of air from one horizontal compartment to the other in the manner and for the purpose hereinafter set forth. There is a horizontal wall 8 or baflle extending from the vertical wall 6 toward the right in Figure 3, with its right hand end terminating a distance from the opposite end wall 3 so that the upper part of the housing is divided off into a flue or horizontal chamher which is a subdivision of the entire drying chamber. The air enters the left hand end of the compartment 9 and passes through the aerofins or air heating units I!) which are heated and which impart their heat to the air entering the compartment 9. I

The air travels from left to right in this compartment and at the end of the baffle or horizontal wall 8 it passes around this wall and into the compartment II below this wall 8 where the air changes its direction and passes from right to left in the second compartment II. This second compartment is defined partly by the horizontal wall 8 just referred to and by the second horizontal wall l2 which at the right hand end in Figure 3 touches or is connected with the end wall 3 whereas the left hand end of this horizontal wall terminates against the frame l3 which surrounds another aerofin or heating unit 14 which is preferably used as sort of a booster to add its heating effect to the air which has passed through the first compartment 9 to the second compart ment H.

The air which has travelled, therefore, through the horizontal compartment l I passes the aerofin or heating unit I4 and this air is further heated and dried by the action of the aerofin or heating unit l4 and it changes its direction from left to right in the third compartment l6, where it passes under the dividing wall l2. This third compartment is defined not only by the outer walls of the heating chamber but on the top by the horizontal wall l2 and on the bottom by another horizontal wall I! which extends at its left hand end from the wall 6 toward the right in Figure 3, and terminates short of the end wall 3 to leave a space for the air to pass from the third compartment l6 into a fourth horizontal compartment I8. This latter compartment is defined in part by the outer walls of the drying chamber and on the top by the wall I! and on the bottom by another horizontal wall I9 which extends from the right hand end wall 3 to the left and in contact with the vertical wall 6.

At 20 we provide a screen to keep the fabric from being drawn out by the suction blower. From the compartment l8 the air is drawn out by means of a suction blower 22 operated by the motor 23 and disposed outside the drying cabinet. We prefer to draw the air through the drying chamber by suction action in preference to a blowing action, although the latter will be operative, but to a less efficient degree.

We have shown the fifth or bottom compartment 24 extending lengthwise of the drying device and at one end there is an opening 25 in the wall to allow external air to enter the chamber 24 at the right hand end in Figure 3, this air being outside air and therefore unheated until it reaches the aerofins, as shown by the arrows. The outside air which enters through the opening 25 passes from right to left in the compartment 24 and this air passes through the opening in the lower portion of the vertical wall8, then rises upwardly in the flue 1, passes from left to right through the upper portion of the vertical wall 6 the latter having openings for this purpose, and then the air passes around and through the portions of the aerofins l0 where it is first subjected to the heat preparatory to its passage through the four horizontal compartments described above.

It will be understood that the drying chamber may be divided into any desired number of horizontal compartments having any number of runs of fabric in each compartment through which the air and the fabric pass in succession and that while we have shown five different horizontal compartments in the drawings, it will be understood that there may be a lesser or greater number than this. Where the cool outside air is allowed to pass first through the lowest compart- 'ment 24, this performs a conditioning operation and serves to cool down the fabric after it is passed through the first four horizontal compartments and has been heated and dried, so that when the fabric emerges from the drying apparatus at thelower right hand end as indicated by the arrow in Figure 3, it will not only have been dried but it will have been cooled down by the atmospheric air travelling through the lowest compartment. 1

If it is not desired to condition the fabric in this manner then the damper 26 near the upper left hand corner of Figure 3 may be opened to allow the atmospheric air to enter through the opening 21 in the wall 4 to pass directly throlmh the aerofin or heating unit Hi to enter the upper horizontal compartment 8 directly instead of taking the air from the lowermost compartment. This allows the device to be used, in either manner according to the nature of the fabric and the resultsto be accomplished. I

There are horizontal rollers 28 arranged at relatively close intervals for each run of the fabric within the drying chamber, which rollers act as local supports for the moving fabric at different places intermediate the propelling rollers. The spacing of the roller 28 next to each propelling roller .is preferably greater than the spacing between consecutive rollers 28, so that athrough the slot 29," and it then passes partly around the first propelling roller 38 which extends horizontally'across the upper portion of the first horizontalcompartment 9.

From there, the. fabric passes over the first row of supporting rollers 28'and it then passes 'to that of the fabric.

through the first rectifying device 3| adjacent the left hand end in Figure 3, and it then passes partly around the second driving or propelling roller 32 whereupon the fabric is reversed in direction and passes from left to right in the second substantially horizontal run 33. Here it passes over a second row of rollers 28 to a point near the right hand end of the drying chamber and preferably above the right hand end of the baffle wall 8. At this location the fabric travels partly around a roller 30 and is then again changed in direction so that it passes from this roller from right to left in what may be called the third'run 34 within the upper compartment 9.

When it reaches the left hand end of this compartment the fabric passes around a second rectifier 3| and thence partly around the second propelling roller 32. It is then changed in direction and travels from left to right to form a fourth run 35 in the upper compartment, travelling over the fourth row of rollers 28. When the fabric reaches the right hand end of the baffle plate 8 is passes partly around a propelling roller 38 and its direction is again reversed so that the fabric passes from right to left, this time forming the upper run 36 below the baflie wall 8.

The fabric at the left hand end of the compartment I l travels around a propelling roller 32, is

fabric.

From the last compartment the fabric passes out through the slot 31 between the. guide rollers 38 partly around the guide roller 39 and then the fabric may be delivered to a finishing machine or apparatus or it may be wound into a roll or otherwise disposed of.

The several arrows in Figure 3 indicate the direction of flow of the air.current in the preferred arrangement. It will be apparent that during some of the runs of the fabric in the horizontal chambers it is travelling with the air current, while in other runs it is travelling counter to the air currents. The general travel of the fabric while shown as being with the flow of air in Figure 3, that is to say, the fabric passes successively from the upper to the next lower compartment, etc., and out of the lower compartment, and while the heated air first enters the upper compartment and then is delivered from the,fourth compartment, it will be apparent that theiiow of heated air may be reversed so that the general travel of the air will be. counter The heated air may be caused to flow inthe reverse direction if desired.

Operatinglas illustrated in the drawings, the hottest airv strikes the fabric when it has its greatest moisture, which is a desirable condition for many kinds of fabrics.

As-statedabove, the slip clutch devices lustrated in our said co-pending application Serial No. 691,522, may be used for operating the fabric drive rollersinthe. present apparatus, but herein we-have shown] a modified form of drive which has certain advantages. In the exterior view of the drying device, as shown in Figure 1,

we have illustrated a driving belt which is endless and which is shown as operating in two vertical runs, the belt passing around the driving pulley 4| which in this case is preferably near the top of the machine, and passing around an idler roller 42 near the bottom of the machine, and the pulley 4| is driven from any suitable source of power being applied to the shaft 43 which carries the pulley 4|.

The belt 40 may be of rubber or rubber composition, and it is preferably somewhat thick. One vertical run of this belt engages against the peripheries of a number of pulleys 44 arranged in a vertical row, each such pulley being fixed on the end of the shaft 45 of each fabric propelling roller 32. the shaft projecting through the vertical wall of the drying chamber so that the pulleys 44 are arranged on these shafts at the exterior of the drying chamber, it being understood. of course, that the belt 40 and its several pulleys are also mounted on the exterior of the drying chamber adjacent one end thereof. Near each pulley 44 there is mounted upon a bracket 4'! (in Figure 4) a stud 48 which forms a pivot for the lever arm 48 Intermediate its ends each of these lever arms has mounted upon it a stud 49 on which an idler, presser roller 50 is freely revolvable.

It will be noted that the center of the stud 49 which is the axis of the roller 50 is slightly below the axis of the shaft 45 on which the pulley 44 is mounted, so that whe the lever arm 48 is moved to the right in Figure 4. the roller 50 presses an adjacent portion of the driving belt 40 against the periphery of the pulley 44 and that it causes a bending of the belt to wrap it slightly around the pulley 44 in order to provide sufficient traction as between the belt and the pulley to cause the latter to be driven by the belt at such times as the pressure roller 50 is pressing the belt against the pulley.

The lower end of each lever arm 48 has a hub 5| with a threaded bore, and there extends through this hub 5| a threaded adjusting sleeve 52. The hollow threaded adjusting sleeve 52 has inserted through it a long connection shown in the form of a wire 53 which is held in place by a collar 54 and set screw 54*, the wire 53 being a loose fit through the hollow adjusting sleeve 52. The compression spring 54 is a loose fit over the wire 53 and is held in place by the collar 54 at one side and the sleeve 52 on the other side. Any pull of the wire 53 from left to right would result in compressing the spring 54', applying a gradually increased pressure against the sleeve 52 which is transmitted up through the lever 48 until this pressure is brought to bear on the belt 40 against the pulley 44 by a pressing action of the roller 59. The effective length of the wire 53 may be adjusted by turning the threaded sleeve 52 in whatever direction may be desired until the proper effective length of wire 53 has been determined, after which the threaded sleeve 52 may be locked into place by the lock nut 52.

The wire 53, there being one of these wires to each lever 48, has its end opposite the threaded sleeve 52 passed through a pivot 55 and fastened to the pivot 55 by a set screw 55. The pivot 55 is inserted in the arm 55 of a lever 65 which is on the exterior of the drier and is fastened on a shaft 51 by a set screw 51, the shaft 51 extending through the side wall of the drying chamber.

Within the drying chamber this shaft carries a pair of parallel lever arms 58 shown in Figures 5 and 6, and there is connected between the bosses 59 on the free ends of these arms a roller 60 extending crosswise of the drying chamber, and which roller is adapted to engage with the fabric in the manner hereinafter set forth to feel the fabric and to move into different positions in accordance with the tautness or looseness of the fabric where the roller engages. This roller is preferably covered with a fabric covering 6| so that it will not injure the delicate surface of the fabric which is being treated.

We have shown the roller as of light construction and consisting of a light cylindrical shell 62 having end pieces 63 secured therein; and these end pieces form bearings on the small rod 64 which forms the shaft of the roller and which is itself mounted in the bosses 59 carried by the lever arms 58.

There is shown a counter weight arm 65 fixed upon the shaft 57 on the portion which projects to the exterior of the drying chamber; and this arm has a series of notches 66 on its upper edge to receive a tooth 6! on an adjustable counterweight 68 which is adjustable to the various posi tions along the arm 65 for the purpose of counterbalancing a portion of the weight of the arms 58 and the roller 60 so that this roller will press very lightly against the fabric, it being intended that the pressure shall only be sufficient to cause the roller to follow the adjacent portion of the fabric as it becomes taut or loose and to offer substantially negligible resistance to the movement of the fabric. The weight 68 may therefore be adjusted along the lever arm 65 so that the roller 60 may remain in contact with the fabric but engage it lightly for the above reasons.

Each propelling roller is shown as constructed of a light hollow cylinder 69 which is covered on its exterior with a fabric 10 which is desirably made of velvet or plush, or other suitable ma terial, this covering being held at one end of the roller by a ring 1| which presses the material into a peripheral groove in the cylinder; and at its other end itpasses around the flange 12 on the flange member '13 on which one end of the cylinder 69 is mounted. The coiled spring 14 expanding against the portion of the covering fabric 10 on the under side of the flange 12 holds this end in place. The flange member 13 is provided with a hub 15 which is mounted on the shaft 45 and is secured thereto by the set screw 16 so that the roller is caused to turn with the shaft 45.

At the right hand end of the apparatus as viewed in Figures 1 to 4 inclusive, there is a second propelling belt 40' disposed to operate in vertical runs, and this belt performs the same functions regarding the fabric propelling rollers at the right hand end of the machine as the belt 40 performs at the left hand end of the apparatus, and the parts associated therewith correspond with those associated with the belt 40 and they will be similarly numbered, but with prime numbers to distinguish them from the parts associated with the belt 40 and to show. at the same time, which parts associated with the belts are similar in function.

It will be observed especially from Figure 1. that in the preferred arrangement the wires 53 whichare connected at the left hand end with the short lever arms 56 extend toward the right of the apparatus and slightly inclined downwardly. so that these wires engage with lever arms '48 and are connected with the lever arms 48 at the left hand end of the apparatus. This arrangement causes the control rollers 60 to directly effect the operation of a propelling roller at the opposite end of the apparatus in order to slow down the propulsion of the fabric as it becomes taut at the right hand side of the apparatus and conversely, to slow down the fabric at the right hand end of the apparatus if the controlling roller 60 at the left hand end of the apparatus is caused to move by a local tightening of the fabric at that end.

There are local guide rollers 18 in Fig. 3, engaging the fabric just after it leaves one of the rollers 30, 32, which idlers serve to cause the fabric to engage a greater portion of the circumference of the rollers 30, 32, in order to secure the desired traction between the propelling rollers and the fabric.

The rectifying devices which are shown in Figures 7 to 12 are placed at advantageous points in the drier, preferably engaging the fabric immediately in advance of the propelling rollers 30, 32.

The strip of material being driven by and running over the rollers 30, 32 has a tendency to run off to one side or the other of the roller, unless there is something to hold the material properly centered .and aligned, especially if the material to be a soft texture, such as a knitted fabric. Where there are superposed layers of the fabric, especially in moist condition, and the fabricchanges in its direction of movement, it has been difiicult to keep the fabric centralized on the rollers and it has been difficult to eliminate creases and wrinkles in the strip of fabric.

We have shown a simple and inexpensive rectifier which automatically rectifies the course of travel of the fabric to counteract its tendency to run off to one side or the other of the rollers and when such tendency arises the rectifier guides the fabric back into central position. There is shown in Figures 7 to 12 inclusive one of the rectifiers embodying part of our invention. The roller 32 shown in Figures 7, 9 and 12 is one of the propelling rollers for propelling the strip of fabric through the drying chamber and a rectifying device is arranged just in advance of such roller and each roller 38.

There is shown a cross member mounted in the uprights 8| of the frame of the drying chamber and within the heating chamber in a stationary position over the propelling roller 32. This cross piece at its middle portion supports an arm 82 which extends forwardly of the propelling roller 32 and above it. At the end of this arm 82 there is a pivot bolt 83 which forms a support for an oscillating frame 84 which is adapted to oscillate in a horizontal plane and to a limited extent around the bolt 83; and in order to allow this frame to move with least resistance we prefer to provide ball bearings 85 interposed around the bolt 83 and on which the frame 84 oscillates.

The swing of the rectifier is limited by adjustable screws 83 which are threaded into the ears 83 on the member 84 and which strike the bar 82.-

The oscillating frame carries thetractionrollers which automatically maintain the fabric centralized and preferably these rollers are constructed as follows: There are shown three rollers 86, 81, 88 and extending parallel to each other, and each roller consisting of a section 89 on the left side ,of the frame 82, and a section 90 on the right side of the frame 82, and preferably these two sections of each roller diverge in relation to each other as shown in Figure '7. The two sections of each roller are shown on an angular shaft 9| which is secured at its end to the brackets 92 which are mounted on the oscillating frame 84. The sections of the rollers are shown as composed of thin cylindrical walls 93 having blocks 94 disposed inside the tubular member and adjacent opposite ends thereof, and these blocks have their bearings on the shafts 9|. The sleeves '95 serve as spacers to maintain the roller sections in proper positions on the shaft.

The cylinders 93 are preferably covered with a fabric 96 which may be velvet or plush in order to have sufiicient traction for the fabric to revolve the several rollers 86, 81, 88 which are in fact idlers. Preferably, one of the roller sections, for instance the section on the right of Figure 8, has a plug 91 in the end of the cylinder 93 which plug projects beyond the end of the cylinder and into the open end of the cylinder 93 of the other roller section. This plug is shaped ,as shown at 98 to provide a member for the travelling fabric to rest against and to prevent the fabric from piling up against the edge of either roller section when it shifts from one side to the other .of the exact central line.

Preferably, all three rollers 86,81, 88 are constructed alike, so that the above description applies to each of them. Of course, it will be understood that two rollers may be used, or more than three rollers, but we have found that three rollers in each rectifier will perform all of the functions desired. We have shown extensions or ears 99 on the frame 84 with rods I08 connected thereto and extending downwardly between adjacent roller sections to prevent either ledge of the travelling fabric from becoming entangled with the ends of the rectifier rollers.

The device shown in Figure 13 is to prevent the heated air from passing through the dividing walls, such as I2 and I9, where the rollers 32 are located. It consists of the plate I02 having turned down ends to which the pivot rod I83 is attached and on which the plate lll2 pivots. The roller l0l is attached to the turned down ends of the plate, the periphery of this roller moving close from one edge of the plate I02 and resting also on the roller 32 to close the aperture in the plate I! or l9, as the case may be, where the roller 32 is located, to prevent the heated air from passing through the opening in the plate I1 and I 9.

Operation When the strip of fabric to be treated has been threaded through the apparatus,- it will appear as shown in Figure 3; that is to say, the fabric coming from another machine or apparatus leads through the slot 29 in the upper right hand corner of the drying chamber and from there the fabric passes from right to left through the upper longitudinal compartment 9; thence through one of the rectifiers; around the left hand feed roller 32, after which the fabric passes from left to right, thence around a roller 30 and from there the fabric passes from right to left on the third run and at the left hand end of the apparatus it again passes through a rectifier and around a feed roller and from there the fabric passes again from left to right .to the right hand end of the baflie 8 whereupon it passes around another feed roller and thence back under the baflle 8.

In this manner the fabric passes back and forth in several runs in each horizontal compartment throughout the four compartments, and it then passes into the lower or fifth compartment where it also travels back and forth in the several horizontal runs and then emerges through the slot 38 at which time the fabric will have been completely dried if that is the object to be attained, or the moisture content may have been reduced to any desired degree. The suction blower 22 will exert a suction action in the compartment llll and this will draw the heated air from the upper horizontal compartment through the one next to it, and thence through the one next below it, etc. until the air which has given up a large percentage of its heat to the fabric and which has extracted moisture from the fabric will be exhausted into the atmosphere by the blower.

While the heated air is travelling in succession through the several horizontal compartments to heat the fabric it extracts moisture therefrom and the operation may be controlled by the speed of travel of the fabric through the drying chamber and by the operation of the aerofins and if uniformity in both of these factors is maintained the condition of the fabric will be uniform when it is delivered from the apparatus.

Difierent horizontal runs of the fabric within the drying chamber are driven by the propelling rollers 30, 32. The controlling rollers 60 which control the operation of the fabric propelling rollers are so disposed in the drying chamber that they rest downwardly on the top surface of the fabric as shown in Figure 3. One of these controlling or feeler rollers is shown as disposed to engage the fabric near each propelling roller, 1. e., to engage the fabric just after leaving the propelling roller. Each of the control rollers rests by very light pressure against the fabric and if there is too much slack in the fabric where one of these rollers rests upon it the roller will move downwardly in following the fabric and this will cause the lever 58, 65 to rock slightly and the short arm 56 of lever 65 will draw on one of the wires 53 and this motion will be transmitted through the wire to one of the levers 48 or one of the levers 48' causing the latter to rock slightly.

This will cause its roller 50, or 50 to press against either the driving belt 40 or the driving belt 40' to create driving friction of one of these belts against one of the pulleys 44 or 44' and this frictional engagement between the belt and the pulley will set the corresponding travelling propelling roller 30 or 32 into operation, or increase its operation as the belt 40 or 40' is wrapped slightly around the pulley 44 or 44'. This will cause the fabric to be driven by one of the propelling rollers to remove part or all of the slack in that part of the fabric where the controlling roller 60 is testing the fabric for its slackness. As the slack in this part of the fabric is gradually taken up by the propulsion set up by the operation of one of the driving rollers, the controlling roller 60 is lifted by the fabric itself.

When this occurs, the pull on one of the wires 53 as described above is released and this releases the pressure of the corresponding roller 50 or 50' against either the belt 40 or the belt 40' as the case may be, and this will reduce or terminate the driving action of the belt upon the particular pulley 44, 44' so that the shaft on which this particular pulley is mounted and the fabric propelling roller on that shaft may slow down or come to a stop and remain quiescent until the same controlling roller again moves downwardly as a result of accumulation of slack in the fabric where that particular controlling roller engages it.

While to some extent the belt 40 or the belt 40 may drive one of the pulleys M, 44 while the pressure of the roller 50 or D is being applied or released, the device will be effective even if it Works on the start and stop principle, that is to say, even if the pulley M or 44 is only driven when the roller 50 or 50' is pressed against the drive belt 40 or 40 under the full action of a controlling roller 60.

Different portions of the total strip of fabric which lie within the drying chamber at one time will be tested by the controlling rollers 60 at different local positions, according to the disposition of these rollers, such as is shown in the drawings, so that different fabric driving rollers in the drying chamber may be performing differently from each other; that is to say, at a moment when one is temporarily idle another drive roller may be operating because control of the propulsion of the fabric is divided up amongst the several propelling devices and they are controlled locally by their respective controlling rollers.

It will not suffice to operate all of the propelling rollers at the same speed or to operate them all at the same definite ratio even with different driving parts moving at different speeds to others because the fabric is undergoing variations in tightness and looseness throughout different portions of the drying chamber and the driving of the fabric locally must conform to the local condition of the fabric, which is possible in the present apparatus. The fabric is undergoing some change in length due to the change of the moisture content in the fabric in the drying chamber, and it is undergoing change of weight due to loss of moisture.

In most cases it is desirable, especially where knitted fabric is being handled, to avoid excessive tension or tautness in the fabric while it is being propelled through the drying chamber or, in other words, it is desired to keep the fabric loose, but nevertheless to avoid having it pile up at any point of its travel, due to excessive looseness. Through the mechanism described herein it is possible to have all parts of the fabric loose or without material longitudinal tension and at the same time to prevent the fabric from piling up at any point, due to excessive looseness.

Under the method described herein, we automatically control the drive of the fabric locally or at various points throughout the drying chamher with means such as the feeler rollers which are controlled by the fabric itself and which bring about local propulsion of the fabric in accordance with these automatic feelers.

The strip of fabric just before it approaches one of the propelling rollers 30 or 32 passes under the first roller 88 of a rectifier, thence partly over the second roller 81 and thence partly under the third roller 86 of the rectifier from which it passes directly onto the propelling roller. The traction of the fabric on the several rollers of the rectifier causes the latter rollers to revolve as they are in the nature of idlers, The rollers, by reason of their formation in divergent sections, will cause any creases or wrinkles in the fabric to be worked off in opposite directions from the median line of the fabric to the edges so that when the fabric reaches the propelling roller 30 or 32 any wrinkles or creases will have been smoothed out and caused to pass off the side edges of the fabric. Thebolt 83 which is the pivotal point of the frame 84 is preferably in the center line of the correct path of travel of the 1 fabric or in line with the middle of the fabric propelling roller 30 or 32.

The fabric in fiat form, whether of a single thickness or a flattened tube, will travel in a horizontal plane and will reach the rectifier from some previous roller or guiding means or from any other source such as a drive roller 30 or 32 in Figure 1. There will be sufficient traction between the rollers 86, 81, 88 and the fabric to cause the former to be revolved by the fabric.

The function of the rectifier is to keep the travelling strip of fabric centralized in relation to the fabric prepellors 30 and 32. If, while the fabric is travelling through the rectifier, it for any reason develops a tendency to lead toward the right on a roller 30 or 32 as viewed in Figure 7, the fabric will travel on the rectifier rollers toward the right, and when this takes place there will be more fabric engaging the rectifier roller sections to the right of the pivotal point 83 and this will cause the rectifier to turn diagonally toward the left in Figure 7 or to swing anti-clockwise; and the rectifier will thereupon immediately develop a left lead in the travelling fabric. This left lead will overcome the previously developed right lead of the fabric or, in other words, the rectifier will automatically equalize the fabric by leading it back toward the correct position.

When this counter lead develops, and starts to bring the fabric back to its correct position, the rectifier will also move from its diagonal position back to its central position so that by the time the .fabric has been corrected in relation to a roller 30 or 32 the rectifier itself will have been brought back to the neutral or straight position at right angles to the correct travel of the fabric, as indicated in Figure 7. The lateral lead caused by the rectifier is therefore brought to an end when the fabric has been brought back to its correct path.

The rectifying action is not sudden but it takes place gradually as is necessary with a wide, soft fabric. If the pivotal screw 83 is arranged directly over the frame 84 the rectifying action will be much slower and more gradual, whereas if this pivotal point is arranged ahead of the frame 84 as shown in Figure '7, there is a greater swing to the rectifier and therefore the rectifying action is quicker. It is preferable to arrange one of these rectifiers adjacent each fabric propelling roller.

If the fabric near the rectifier tends to develop a left lead the opposite action will take place to that described above, and the rectifier will provide a right counter lead and bring the fabric back to its correctposition. The rectifier operates on substantially the full width of the fabric rather than locally, and instead of creating wrinkles in the strip it irons and smooths them out. A rectifying device may be placed to act on the fabric before it passes into the drying chamber to insure accurate entry of the fabric into the drying chamber. Other rectifiers, independent of each other, and all automatic in their operation are preferably used in the drying chamber as shown, to insure uniform directional progress of the fabric.

While we have illustrated and described a certain form in which the invention may be embodied, we are aware that many modifications may be made therein by persons skilled in the art without departing from the scope of the invention as expressed in the claims. Therefore we do not wish to be limited to the particular form shown or to the details of construction thereof.

Having described our invention, what we claim 1s:

L'Apparatus for continuously drying lengths of fabric which comprises a vertical series of horizontal drying compartments, means for conveying the fabric through the compartments in sequence, an air inlet adjacent the fabric discharge end of the last compartment of the series, an air passage connecting the opposite end of said last compartment with an end of the first compartment of the series, air passages connecting the ends of the compartments except the last compartment in series forming a continuous passage for the air through said compartments, and an outlet for the air from the next to the last compartment of the series.

2. Apparatus for continuously drying lengths of fabric which comprises a plurality of communicating drying compartments, a fabric entrance in the first of the compartments and a fabric exit in the last of the compartments, fabric conveying mechanism within the compartments for conveying the fabric through the compartments successively from the entrance to the exit, an air passage connecting an end of each compartment with the adjacent end of the next successive compartment, excepting the last compartment, a connecting air passage connecting the last compartment with the first compartment, heating means imparting heat to the air entering the first compartment, an air vent in the last compartment admitting fresh air, an air exhaust vent in the next to the last compartment through there is an air vent in said connecting passage' adapted to lead air'into the air flow to the series of compartments.

4. The method of drying traveling lengths of fabric comprising conveying. the fabric in fiat spread condition in a plurality of parallel runs in each of a series of communicating drying compartments, subjecting the fabric while in all but the last of said compartments to a heated current of air entering the first of said compartments and moving through each compartment in the same general direction as the fabric, cooling the fabric in the final drying compartment by passing a fresh current of cool air through said compartment, heating the cool air leaving the last compartment and supplying the air to the first compartment and continuously maintaining a predetermined slackness in each parallel run of fabric throughout the .drier by regulating the speed of propulsion at the end of each run in accordance with the slackne ss of the fabric at the beginning of the run so that each run of fabric has a predetermined freedom to respond to the drying conditions to which it is subjected.

' 5. The method of drying as set forth in claim 4 in which the heated current of air is first maintained against further heating so that the temperature of the air at first decreases and then reheating said air current a predetermined amount to raise its temperature within the safe temperature limitof the partially dried fabric and then permitting the temperature of the air to decrease as the air current further progresses along with the fabric.

6. Apparatus for continuously drying lengths of fabric which comprises a plurality of communicating drying compartments, a fabric entrance in the first of the compartments, and a fabric exit in the last of the compartments, fabric propelling means within the compartments comprising fabric driving rolls located at the ends of each compartment for conveying the fabric in spread fiat form and in a plurality of superposed sinuous runs within each compartment and through the compartments successively from the entrance to the exit, a variable friction drive for each driving roll and a controlling roller riding on the fabric, control means for each variable friction drive operated by the controlling roller and automaticaly varying the friction drive in accordance with the slackness of the fabric, an air passage connecting an end of each compartment with the adjacent end of the next successive compartment, heating means imparting heat to the air entering the first compartment and air propelling means causing the heated air to fiow from one compartment to the next through the connecting air passage from the first of the compartments to the last of the compartments so that the fabric and air progress in the same requence through said compartments.

7. Apparatus as set forth in claim 6 in which the fabric driving rolls at corresponding ends of the drying compartments are in vertical alignment adapted to be driven from a single source of power.

8. Apparatus as set forth in claim 6 which includes means for reheating the air a predetermined amount at a point intermediate the first and last drying compartment.

9. Apparatus as set forth in claim 6 having an inlet for the air entering the first compartment, said inlet being opposite the fabric entrance so that the initial run of said fabric is countercurrent to the direction of flow of the air.

SAMUEL COHN. JULE'S G. WALTER.

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