US 2832642 A
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April 29, 1958 F. R. LENNOX 2,832,642
camxuuc DEVICE Filed Jan. 3, 1956 42 INVENTOR.
E 7 For/e37 R. L ennox I i 28 y 52 i 50b HTTORN' Y6 United States Patent CRINKLING DEVICE Forrest R. Lennox, Coleman, Mich., assignor to The Dow Chemical Company, Midland, Mich., a corporation of Delaware Application January 3, 1956, Serial No. 557,117 2 Claims. (Cl. 299-432) This invention relates to apparatus adapted to be used in the drying or cooling, or both of extruded fibers of small diameter and particularly to a nozzle for use in making crinkled fibers from extrudable organic thermoplastics.
Specifically, the invention will be described in connection with the making of crinkled fibers from extrudable normally crystalline sarans. However, the utility of the apparatus of the invention is not limited to use in the making of saran fibers. The use of the apparatus of this invention is, by way of example, described in Widiger and Hendershots co-pending application, Serial No. 534,988, filed September 19, 1955, for Method of Spinning Polyoefins, and assigned to the same assignee as the instant case.
A method of making crinkled fibers from extrudable normally crystalline sarans is disclosed and claimed in U. S. Patent No. 2,542,973 to N. W. Abernethy.
The Abernethy method comprises extruding fine filaments of a normally crystalline saran downwardly through air and directing against all sides of each such filamenta plurality of streams of a gas inert to the filaments, the streams of gas converging upwardly to define a core with its apex slightly below the extrusion orifice, and then super-cooling and stretching the filaments to obtain a filamentary product having a natural crinkle.
The Abernethy method, while successful when used in the production of most saran fibers, is not as satisfactory as could be desired when fibers of extremely small diameter (10 denier and less) are being made. Such small and delicate fibers l0 denier and less) are adversely affected by the turbulence created when the plurality of streams of gas from the nozzle are directed against the fibers or filaments.
The turbulence often forces the fine fiber filaments, which are sticky as they enter the turbulent zone, into contact with each other, causing coherence of several strands. Usually one or more of the cohering strands breaks, causing stoppage of the spinning operation and the loss of some spun fibers as scrap. The turbulence also causes non-uniformity in the degree of crinkling of the strands.
According, an object of this invention is to provide an improved nozzle for cooling sticky strands of extruded fibers.
Another object of this invention is to provide an improved means for directing cooling gas through a cluster of fine, sticky plastic strands while minimizing turbulence of the ambient atmosphere.
In accordance with this invention there is provided a hollow annular member having a slit circumscribing the member and facing generally towards the cluster of filaments. Gas is fed into the annular member through one or more suitable connectors and is directed towards the cluster of filaments through the slit. The width of the slit is adjustable in order that a single annular member be capable of use in drying filaments of various thicknesses.
The invention, as well as additional objects and advantages thereof, will best be understood when the following detailed description is read in connection with the accompanying drawings, in which:
Fig. 1 is a diagrammatical view showing the nozzle of this invention as used in the crinkling of film;
Fig. 2 is a plan view of the nozzle shown in Fig. 1;
Fig. 3 is a side elevational view of the nozzle of Fig. 2, and
Fig. 4 is a fragmentary sectional view, scale, through the annular nozzle.
Referring to Fig. l, a cluster of filaments 10 are extruded from the orifices of an extruder 12. The cluster of filaments 10 pass downward through an annular nozzle, indicated generally by the numeral 14, which directs a sheet-like stream of air inwardly towards the cluster 10. After the cluster of filaments 10 passes through the nozzle 14, the filaments pass over guide rolls 16, 18, a series of stretching rolls 2t), 22, and are wound on a spool 24.
Referring to Figs. 2, 3, and 4, as well as to Fig. 1, the nozzle 14 comprises an upper segment 26 and a lower segment 28, each segment having a channel 30a and 30b in one side thereof. The channeled sides of the segments face each other when the nozzle is assembled. The segments 26, 28 are held together by means of bolts 32 which are disposed around the non-channeled sides 34, 36 of the nozzle and which extend between .the two segments. The outer peripheral surfaces 38 and 40 which face each other are separated by a gasket or shim 42. The segments 26 and 28 are so machined that the inner peripheral surfaces 44 and 46 fit tightly against one another when the shim or gasket 42 is in place and the segments are bolted together.
The annular channels 30a and 30b face each other to form a common interior channel through which gas is directed during the operation of the nozzle. The surfaces 44 and 46, which abut against each other when the screws 32 are tightened, may be forced apart by means of an array of screws 48 which extend through the upper segment 26 and bear against the surface 46 of the lower segment 28. The nozzle 14 has two gas inlet ports 50 and 52, lying on diametrically opposite sides. of the nozzle 14, which comprise tapped bores in the lower segment 28, inlet bores 50, 52 communicating with the gas flow channel (30:: and 30b) which comprises the hollow interior part of the nozzle 14. t
In one embodiment of the invention, used with a vertical 1% inch extruder nozzle, the gas nozzle has an outside diameter of 9% inches, an inner diameter of 7 4 inches, a thickness of 1 inch, a central gas channel or duct (30a and 30b) /2 inch square and encircling the nozzle and nozzle orifice (due to the screws 48 being tightened) of .001 inch inclined upwardly at an angle of 10 degrees from the horizontal. The segments 26, 28 are held together by twelve screws or other small machine screws or bolts which are spaced equi-distantly around the nozzle. An array of twelve 9 screws, extending through the inner leg of the U-shaped upper segment (from the surface 34 to the surface 44), is utilized to force apart the surfaces 44 and 46 to provide a flow channel between the surfaces. The width of the flow channel is controlled by the setting of the screws 48. The shim or gasket 42 between the upper and lower segments 26-28 is .003 inch thick and is conveniently made of paper. Other gasket material of suitable thickness may be used.
The gas flow channel between the surfaces 44 and 46 directs, in effect, a sheet of air or other fluid against and through the cluster of filaments 10. The sheet of air or fluid does not have the degree of turbulence which is present when individual streams of fluid are direct on an enlarged towards the cluster 10. This reduced turbulence allows smaller fibers to be dried in this manner than it has heretofore been convenient to do.
The screws 48 may easily be advanced or retracted to permit adjustment of the width of the flow channel between the surfaces 44 and 46. Thus, by adjusting the width of the flow channel and the fluid pressure applied to the nozzle 14, one nozzle 14 may be used in the drying of many types of fibers. The ease of control of the nature of the sheet of air directed at the cluster of filaments results in less shutdown of fiber production and in more uniformity of crinkling of the individual fibers.
The angle at which the fluid sheet (usually air) strikes the cluster of filaments is controlled by the angular relationship between the surfaces 44, 46 and the vertical axis of the nozzle. While directing the sheet of air or other fluid upwardly at an angle of about 10 degrees has proven satisfactory for general usage, it is obvious that diiferent fibers or production facilities may require different angles of approach of the sheet of fluid. For example, when extremely fine fibers were extruded with the nozzle 14 positioned close to the extruder 12, the nozzle was turned upside down and the sheet of air directed downwardly away from the extruder. In this last mentioned case, less turbulence of the fibers resulted and less cooling of the extruder 12 occurred.
1. A nozzle for use in the drying or cooling, or both, of fibers made from extrudable organic thermoplastics, comprising a pair of annular plates each having a circular groove in one face thereof, the grooves in each plate being of approximately the same diameter, means for joining together said pair of plates with their grooved faces in juxtaposition, said plates being joined along the outer periphery thereof, and means for forcing apart the inner peripheral parts of each plate to provide a passageway extending from said duct to the exterior of said plates.
2. A nozzle in accordance with claim 1, wherein the means for forcing apart the inner peripheral parts of each plate comprise an array of screws, each screw passing through one plate and adapted to bear against the other plate.
References Cited in the fileof this patent UNITED STATES PATENTS 1,934,618 Briggs et a1 Nov. 7, 1933 2,032,606 Whitehead Mar. 3, 1936 2,269,901 Bletcher et a1 Jan. 13, 1942