US3420983A - Rotating drum heater for synthetic yarn - Google Patents

Description

Jan. 7, 1969 H. w. MCCARD ETAL 3,420,983 ROTATING DRUM HEATER FOR SYNTHETIC YARN Filed Sept. 2l, 1966 Sheet Jan- 7, 1969 H. w. MccARD ETAL 3,420,983

ROTATING DRUM HEATER FOR SYNTHETIC YARN Filed Sept. 2l, 1966 Sheet 2 of`2 3% Zig. f .(5,53 Kg 7 f A I United States Patent O 4 Claims ABSTRACT F THE DISCLOSURE A device for continuously heat treating running lengths of heat treatable synthetic yarn, having a housing, a shaft rotatable within the housing, a hollow heat conductive metal drum mounted on t-he shaft and adapted to receive a plurality of turns of yarn fed onto the drum at one end and removed from the other end, the drum having a series of grooves of c-hanging circumference starting near the center and progressively decreasing in diameter toward the take off end of the drum in accordance with change in length in the yarn as it is heated, a heating element mounted to the housing about the shaft within the hollow of the drum and a post mounted on the housing for longitudinally separating the turns of yarn about the drum.

This invention reates to a device for heating running length of yarn and more particularly to a device for heat treating synthetic continuous filament yarn.

The invention is concerned with a yarn heating device for -heat treating synthetic and especially thermoplastic contin-uous filament yarn, which may be employed as an adjunct to any of a wide variety of textile devices. For example, the yarn heater of the invention may be employed to improve the stability of synthetic yarn, to reduce the residual shrinkage of such yarn, to reduce the residual stretch of such yarn, as an adjunct to false twisting yarn to increase its bulk and stretch characteristics as by imparting a permanent S or Z twist to the yarn, or for other purposes.

In conventional false twisting mechanism for nylon or other yarn, long heating tubes |have been employed containing electrical resistance coils, air, steam, or other heat exchange fluids. The nylon yarn as well known is heated to a temperature approaching its melitng point.

In todays modern process machinery, running speeds of up to 150,000 r.p.m. and greater wherein the linear speed is of the order of 40 yards/ minute and upward have been reached and this has necessitated using heating tubes of up to 30 to 45 inches in length so as to provide enough heating area to reach the required temperatures. Such mechanisms, however, are not only space consuming but often very inefficient in reaching the temperature required to soften the synthetic yarn.

It is therefore an object of this invention to provide a more compact and more efcient yarn heater.

It is a further object of this invention to eliminate the long heater tube in a yarnheater by providing a heater for the yarn wherein the yarn is run circumferentially around a drum heater.

It is a further object of this invention to provide a yarn heater that is compatible with textile mechanisms at higher speeds of operation.

It is a further object of this invention to internally heat the drum to provide the source of heat for the yarn.

It is a further object of this invention to provide more accurate temperature control in the heating of yarns.

It is a further object to avoid damage and to reduce snagging of the yarn during the heating process by r-unning the yarn around a smooth rotatable heated drum.

A further object is to allow for shrinkage or produce stretch of the yarn during heating by tapering the drum inwardly or outwardly toward the take olf end, or to provide both features.

A further object is to provide a plurality of independent grooves on the drums surface, wherein the effective diameter at the bottom of the grooves progressively decreases, or increases, or increases and decreases, toward the take off end of the drum which allows for shrinkage or provides stretch, or a combination thereof, and also keeps the turns of yarn longitudinally separated on the drum.

A further object is to provide a Xed guide post adjacent the revolving drum heater to keep the turns of yarn longitudinally spaced apart on the surface of the drum.

A further purpose is to drive the drum by an electric motor of limited torque capability, such as a shaded pole induction motor through a cone pulley so that precise adjustments of speed can readily be accomplished, but the drive can function notwithstanding that it is not previously adjusted at the speed at which the yarn is received from further mechanism or taken olf by further mechanism.

Further objects will appear from the following description of the drawings.

FIGURE l is a plan view of the yarn heater of this invention.

FIGURE 2 is a top plan view of the heater of FIG- URE l.

FIGURE 3 is a fragmentary right side view of the heater of the FIGURE l.

FIGURE 4 is an enlarged cross sectional view of the heater taken along the lines 44 of FIGURE 3.

FIGURE 5 is an exploded perspective view showing the relationship between the various parts of the heater.

FIGURE 6 is a perspective view of the yarn heater in operation showing the travel of the yarn around the circumference of the dr-urn.

FIGURE 7 is an axial section of a modied contour for the drum, as used in the invention.

FIGURE 8 is an axial section showing a further modication of the drum contour to stretch the yarn after heating.

FIGURE 9 is a view similar to FIGURE 6, showing the drum of FIGURE 8 applied in the processing of yarn using a fixed guide post, as shown in FIGURE 6.

FIGURE l0 is an axial section of a modified embodiment of a drum according to the invention which first stretches the yarn and then permits it to shrink after heating.

FIGURE ll is a view showing the drum of FIGURE 10 in use in cooperation with a lixed guide post, as in FIGURE 6.

FIGURE 12 is a side elevation partially diagrammatic showing the drive for the heater of the invention.

With reference to the drawings there is shown a yarn heater consisting of a drum 20 suitably secured as by means of a screw 21 to a hollow axle or shaft 22 rotatably supported within a housing 23 by bearings 24. The housing flares outwardly forming a dish shaped depression 25 at one end wherein there is secured a ceramic or other suitable rigid insulating material plate 26 that extends upwardly forming a cylinder 27 about the axle 22 of the drum. The plate 26 is bolted to the housing by suitable fastening bolts 28 and also by a xed guide post 34, the function of which will be further described below. The bolts 28 pass through the housing and into a support element 29 of the textile machinery to secure the heater in its proper location.

Supported by the ceramic plate and adjacent the interior surface of the drum 20 as shown in FIGURE 4 is a heating element 30 which preferably is an electric resistance coil having electrical leads 30 but may alternatively be air, steam or any other type of heat exchange uid heater. Alternatively heating coils may be provided with suitable connections in the interior structure of the drum itself. A vent 31 is provided in the side of the hollow axle 22 to permit air circulation and consequent cooling of the bearings 24.

The drum can be made of aluminum or any other good heat conductive metal and should preferably be coated with cermet or any other substance that will prevent stain from being imparted to the yarn as it passes over the drum. The feeding end of the drum is cylindrical having a lip 32 which prevents the yarn from falling olf the end of the drum.

In some forms of yarn such as nylon allowance should be made for shrinkage in the yarn due to heating as in FIGURES l to 6 inclusive, and thus a plurality of grooves 33 have been provided on the surface of the drum starting around its mid section and decreasing in diameter toward the take off end' of the drum. These progressively deeper grooves allow for shrinkage caused by the heating and/ or twisting of the yarn. Instead of a plurality of grooves a cone shaped drum may be provided with a large diameter initially tapering smoothly to a smaller one at the take off end.

In the particular embodiment shown, the irst groove 33' would have a diameter approximately 5% less than the diameter of the cylindrical portion of the drum, the grooves progressively getting deeper until the last groove 332 had a diameter approximately less than the diameter of the drum. However, it will be understood that the decrease in diameter of the grooves may be greater or less 'depending upon the amount of shrinkage which will occur in the yarn to be processed. While three grooves have been shown on the drum in the drawing, any number can be used depending on the kamount of shrinkage of the yarn and the size of the drum.

In operation of the device as shown in FIGURE 6, the yarn is fed from a package not shown on the left onto the lower end of the drum 20 and off the top end of the drum after being properly heated into other textile mechanism not shown which requires that the yarn be heated.

It has been found that it is advantageous to guide the yarn around a guiding element or post 34 having a plurality of grooves 35 running transverse to the length of the post. The yarn passes around the fixed guiding post 34 and then takes a turn around the drum and in this way the post keeps the yarn passes longitudinally separated and additionally prevents creeping of the yarn. The posts are easily removable and hence interchangeable for different size yarn making the heater adaptable for various sizes without having to change the heater drum itself. Alternatively an idle smaller drum rotatably mounted on the device and containing grooves therein may be used in place of the xed guide post to keep the yarn passes separated.

In an actual example, nylon yarn of 70 denier having 34 filaments and yarn of 70 denier having 17 rilaments were wrapped around a drum revolving at high speed (spindle speed about 120,000 r.p.m.) and heated to a temperature from about 350 to 450 F. The device of FIGURES 1 to 6 is particularly suitable for polyester yarn. The yarn should be heated to a temperature approaching its melting point so that it will be suiciently softened to receive a permanent set. The number of passes of yarn around the drum is determined by the speed of the drum and the length of time the yarn should be in contact with the drums surface in order to reach the required temperature.

The drum diameter is not critical and it has been constructed with the smooth cylindrical portion over part 'of its surface so that the span of time required for the heating can be adjusted merely by taking off or adding more turns of the yarn to the drum and/or increasing or decreasing the speed of travel of the yarn. While the initial cold torque of the heating device is nominal, once the mechanism is at operating temperatures the drag on the yarn is negligible.

A cover not shown may optionally be placed over the mechanism after it has been threaded with the yarn having necessary inlet and outlet ports in an effort to conserve the heat and to prevent exposure of the yarn to outside elements or possible dangers of breakage.

FIGURE 7 is a modification of the drum construction shown in FIGURES 1 to 6 provided with relatively sha1- lower, progressively decreasing annular grooves 333 at the take off end, permitting shrinkage of the yarn after heating. This permits 10% shrinkage in four steps.

In some cases it is desirable to actually stretch the yarn rather than shrinking it. In FIGURES 8 and 9 the annular grooves 334 at the take oif end are progressively larger than the drum and positively stretch the yarn 12% in four steps, as shown. This form is especially useful for nylon where considerable permanent twist is imparted, as in stretch yarn, and it is desirable to obtain a bulking effect.

FIGURES 10 and 11 show a modied form of drum, which at the take oif end has first an annular groove 335 larger in diameter than the drum which stretches the yarn and then a succession of annular grooves 336 smaller than the dum, which permits the yarn to shrink. This is useful particularly to produce novelty. yarns that have unusual effects, as for example for polyester yarns for the piles of carpets and rugs. This illustrates the concept of having the bottoms of the grooves change their dirnension in one direction and then in another direction toward the take olf end.

FIGURES 7 to l1 inclusive show a slightly different construction of the drum at the point where it engages the spindle, and the insultation of the heater is appropriately relieved to avoid interference.

The yarn can be pulled around the drum by suitable means in which case the drum will idle, but in many cases the drum will be driven. This presents a problem since the yarn will be received from other mechanism at a speed controlled by such other mechanism and passed on to further mechanism at a speed controlled by the further mechanism. It is thus possibile that the speed of the drum lmight be slightly different from the speed at which the yarn is either received or taken off. To allow for this contingency, I prefer to drive by a cone pulley 38 on the rear end of axle or shaft 22 which is engaged by a suitably rubber or plastic rim of driving wheel 40 on shaft 41 of driving motor 42 which is adjustable along a path suggested by the arrows 43, conveniently providing adjusting guide-ways and clamping means not shown. The motor is desirably a motor of limited torque so that if it is set at a slightly improper speed with respect to the predetermined travel of the yarn the motor will slightly slip in either direction. A shaded pole induction motor or a synchronous variation thereof is convenient for this purpose.

Instead of nylon and polyster, the heating drum is also applicable to other types of synthetic yarns which include but are not limited to the following such as: polyvinyl chloride, polyvinyl chloride acetates, cellulose acetates, polypropytlene and other thermoplastic fibers.

The invention has thus provided a compact and inexpensive heater for yarn that is accurate, efficient and readily adaptable to all sizes and types of yarn and machine speeds without additionally adding any risk to the process such as breaking of the yarn with the consequent failure of the operation and the necessary restarting of the process.

In view of our invention and disclosure varations and modifications to meet individual whim or particular need will doubtless become evident to others skilled in the art, to obtain all or part of the benefits of our invention without copying the apparatus shown, and we therefore claim all such insofar as they fall within the reasonable spirit and scope of our invention.

Having thus described our invention, what we claim as new and desire to secure by Letters Patent is:

1. In a device for continuously heat treating running lengths of heat treatable synthetic yarn to impart bullk and stretch characteristics, a housing, a shaft rotatably supported within the housing, a hollow lheat conductive metal drum mounted on the shaft and adapted to receive a plurality of turns of yarn fed onto the drum at one end and removed from the other end, said drum having a series of grooves of changing circumference starting near the center and progressively decreasing in diameter toward the take off end of the drum in accordance with change in length in the yarn as it is heated, a heating element mounted to the housing about the shaft Within the hollow of the drum and a post mounted on the housing for longitudinally separating the turns of yarn about the drum.

2. A device of claim 1 wherein the drum is of aluminum.

References Cited UNITED STATES PATENTS 7/ 1940 Coleshill et al.

8/ 1943 Bert-hold.

6/1952 Barker 28-71.3 X 3/1956 Herbert et al. 28-71.3 X l/ 1962 Kleekamm et al.

1/ 1963 Fritzemeier et al. 28-71.3 X 7/ 1966 "Michalek,

GEORGE HARRIS, Primary Examiner.

ROY N. ENVALL, JR., Assistant Examiner.

U.S. Cl. X.R.

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