Method and apparatus for heating thermoplastic yarn
United States Patent [:91  
 McWhirter l l METHOD AND APPARATUS FOR HEATING THERMOPLASTIC YARN [75] Inventor: Joe R. McWhirter, McAdenville,  
 [73] Assignee: Pharr Yarns. Incorporated,  
 McAdenville. NC.  
 [22] Filed: Jan. 7, 1974 [2|] Appl No; 431,239  
 [52] US. Cl. 34/24; 34/31; 34/159;  
  34/l62; 34/203; 34/208; 28/72 SP; 68/5 C [51] Int. Cl. F26b 5/00 [58] Field of Search 28/58, 72 SP, 72 HR;  
 8/1493, [50; 68/5 C, 5 D; 34/2l, 23, 24, 3], I5], I48, 155. I62, 203, 207, 208, 2l7, I59  
 Primary E.\uminerCarroll B. Dority, .lr.  
 Assistant Examiner-Larry l. Schwartz Attorney. Agent, or F irmParrott, Bell, Seltzer, Park &amp; Gibson Apr. 8, 1975 [57] ABSTRACT The present apparatus is adapted to heat yarn which is confined in a uniformly light mass in elongate perforate bags and includes an elongate steam chamber with an endless conveyor for moving the elongate bags through the steam chamber. The conveyor is guided through a zig-zag path of travel to provide a series of upwardly and downwardly inclined sections providing successive peaks and valleys. Carrier means is spaced along the conveyor for engaging the elongate bags and for successively moving the bags up the upwardly inclined sections and permiting the bags to roll down the adjacent downwardly inclined sections to remain in the corresponding valleys and be rotated by said con veyor for a predetermined period of time until again moved up the next successive upwardly inclined section. While the bags are being carried through the steam chamber, they are thus rolled down the downwardly inclined sections. rotated in the valleys and remain in a stationary position as they are raised up the upwardly inclined sections.  
 ll Claims, 6 Drawing Figures METHOD AND APPARATUS FOR HEATING THERMOPLASTIC YARN The present invention relates generally to an apparatus and method for heating thermoplastic yarn which is contained in elongate perforate bags and more particularly to a method and apparatus for subjecting the bags of yarn to a steam treatment to develop latent bulk and kink in the yarn.  
  US. Pat. No. 3,619,875 discloses an apparatus and method of processing thermoplastic yarn which includes forming the yarn into a substantially uniformly loose mass within a flexible porous bag, developing the latent bulk in the yarn, subjecting the yarn to steam in a rotary tumbling machine, heating-setting the yarn in an autoclave, and thereafter withdrawing the heat treated yarn from the bag and winding it into a suitable package. The loading and unloading of the bags into and out ofthe rotary tumbling machine requires laborious and time-consuming handling of the bags and it is difficult to insure that each of the bags in the rotary tumbling machine is subjected to the identical conditions. Also, it is difficult to maintain uniform treatment of bags which are subjected to steam and tumbled in different machines or in separate batches.  
  With the foregoing in mind, it is an object of the present application to provide an apparatus and method for heating thermoplastic yarn in elongate perforate bags by successively passing the bags through an elongate steam chamber while subjecting the successive bags to identical treatments as they are passed through the steam chamber and so that the yarn in each of the bags is uniformly bulked in a continuous manner.  
  In accordance with the present invention, an elongate steam chamber is provided with an endless conveyor extending through the chamber and following a zig-zag path of travel to provide a series of upwardly and downwardly inclined sections providing successive peaks and valleys along the conveyor. Carrier means is spaced along the conveyor for engaging the elongate bags and moving the same through the chamber so that the bags are successively moved up the upwardly inclined sections and are permitted to roll down the adjacent downwardly inclined sections where they remain in the corresponding valleys and are rotated by the conveyor until again engaged by the carrier means to be moved up the next successive upwardly inclined section. The temperature in the elongate chamber is controlled so that each bag which passes through the chamber is subjected to the same condition and the yarn in each of the bags will be uniformly bulked and developed.  
  Other objects and advantages will appear as the description proceeds when taken in connection with the accompanying drawings, in which FIG. I is a side elevational view of the yarn heating apparatus of the present invention;  
  FIG. 2 is a longitudinal sectional view of the apparatus;  
  FIG. 3 is a perspective view of one of the yarn bags prior to steaming of the yarn;  
  FIG. 4 is a perspective view of one of the bags after it has passed through the steam chamber;  
  FIG. 5 is an enlarged transverse vertical sectional view through the steam chamber, being taken substantially along the line 5--5 in FIG. 1;  
  FIG. 6 is a fragmentary isometric view of a portion of the upper reach of the conveyor and illustrating the manner in which the peaks and valleys are formed by the conveyor with a yarn bag being rotated in one of the valleys.  
  The yarn heating apparatus includes a substantially rectangular. horizontally disposed, elongate chamber 10 which is perferably insulated to prevent escape of steam and to maintain an inside temperature. The elongate chamber 10 inspection and access windows 11 spaced along opposite sides thereof and is supported on built-up opposite side frames 12 and 13 provided with suitable connecting cross-pieces 14 (FIG. 5) An endless conveyor, broadly indicated at 15 has its upper reach extending through the chamber I0 and is provided with entrance and exit end portions extending outwardly from the corresponding entrance and exit ends of the chamber 10. An electric motor I6 (FIG. 1) imparts rotation to a drive chain 17 which is operable to impart continuous movements to the conveyor 15. The conveyor includes a pair of spaced-apart sprocket chains 18 and I9 and connecting slats 20 which are of inverted U-shaped configuration in cross-section and extend between and are connected at opposite ends to the chains 18 and 19.  
  As illustrated in FIG. 2, guide means is provided for moving the upper reach of the conveyor 15 in a zig-zag path of travel through the chamber 10 to provide a series of upwardly and downwardly inclined sections providing successive peaks and valleys along the upper reach of the conveyor. In the present instance, the guide means for the upper reach of the conveyor includes a series of spacedapart upper sprockets 22 and a series of spaced-apart lower sprockets 23. The sprockets 23 are positioned between the upper sprockets 22 and are supported on the inner ends of stub shafts 24 which extend outwardly through opposite sides of the chamber 10 and are suitably supported in bearings 25, fixed to the side frames l2, 13. The upper sprockets 22 are supported on stub shafts 26 which extend outwardly through opposite sides of the chamber 10 (FIG. 5) and are rotatably supported in bearings 27 fixed on the side frames 12, I3.  
  Carrier means, in the form of semi-circular carrier plates 30, are spaced along the conveyor 15 for engaging the elongate bags laid on and across the entrance end portion of the conveyor for moving the bags into, through, and out the exit end of the chamber 10. The carrier plates 30 move the bags up successive upwardly inclined sections and permit the bags to roll down the adjacent downwardly inclined sections to remain in the corresponding valleys and be rotated by the conveyor until again engaged by the carrier plates 30 to be moved up the next successive upwardly inclined sections, as illustrated in FIG. 6. The carrier plates 30 are connected at their lower edges to the slats 20 and extend upwardly therefrom with the inwardly bowed portions extending in the opposite direction from the direction of movement of the conveyor.  
  The distance from one edge to the other of the carrier plates 30 is slightly greater than the diameter of the bags and the opposite ends of the carrier plates 30 are perferably closed by end plates 31. As illustrated in FIG. 6, the slats 20 are spaced fairly close together and the distance between the slats is less than the diameter of the bags so that the bags will be supported by the slats. As will be noted in FIG. 6, the slat directly behind the carrier plate 30 is omitted so that when the carrier plate reaches the bottom of the valley it can be tilted rearwardly to pass partially through the conveyor.  
  A suitable frame 35 is provided at the entrance end of the steam chamber (FIG. I) for supporting the entrance end portion of the conveyor so that bags may be laid across the conveyor and picked and carried into the steam chamber by the carrier plates 30. Ad justment means 36 is provided on the frame 35 so that any slack in the conveyor 15 may be taken up. As the bag is moved along by the conveyor and into the entrance end of the chamber, it engages and moves under a rubber flap or entrance door 37 (FIG. 2). When the bags. indicated at B in FIG. 3, are placed on the conveyor 15, they are about inches along and l() to II inches in diameter. After passing through the steam chamber 10 and being subjected to the steam treat ment, they are about 9 inches in diameter and are about 24 inches long, becoming elongated, as illustrated in FIG. 4 at B.  
  The exit end of the chamber 10 is provided with a frame 40 which supports the exit end portion of the conveyor 15 and a drive sprocket 41 which are rotated by the drive chain 17 from the electric motor 16. As the bags are moved out the end of the exit end of the steam chamber 10, they engage and move a rubber flap or exit door 42. The bags are successively dropped onto a tilted chute 43 and roll onto a support table 44 where they may be removed by the operator. Inwardly extending guard plates 46, 47 (FIG. 5) are provided along opposite sides of the steam chamber 10 and their lower edges follow the path of travel of the conveyor chains 18, I9. The guard plates 46, 47 are provided to prevent the bags from becoming entangled with the chains l8, I). The lower reach of the conveyor I5 moves from left to right in FIG. 2 and is supported at spaced intervals on sprockets 50, SI, extending along opposite sides and supported for rotation on the side frames l2, 13 (FIG. 5].  
  Means is provided for creating a steam atmosphere in the chamber 10 and includes steam pipes spaced along the chamber and adjacent the upper reach of the conveyor. The steam pipes spaced below the upper reach of the conveyor includes upper pipe sections 54 and lower pipe sections 55 which extends transversely of the chamber. The upper and lower pipe sections 54, 55 are equally spaced below the successive peaks and valleys of the upper reach ofthe conveyor. These upper and lower pipes sections 54, 55 are connected to a manifold line 56 which feeds steam to a heating zone of the chamber from a suitable source of steam, indicated at 60. Suitable control valves 61 are provided to control the amount of steam being sent to each of the heating zones in the chamber 10.  
  A steam pipe 62 is provided above the upper reach of the conveyor and follows a sinuous path from one end ofthe chamber to the other. The steam pipe 62 is supported above an inverted V-shape baffle plate 63 (FIG. 5) which also extends from one end of the chamber to the other and is positioned between the upper reach of the conveyor and the steam pipe 62. The baffle plate 63 is of sufficient width (FIG. 5) to direct condensation down opposite sides of the chamber and to prevent direct contact of the condensate with the bags being carried through the chamber by the conveyor.  
 METHOD OF OPERATION Bags B are laid across the conveyor I5 and in advance of each of the carrier plates 31 so that they are successively carried into the steam chamber 10 by the conveyor. The amount of time that the bags remain in the chamber may be varied by increasing or decreasing the speed of the conveyor 15. The temperature in the chamber 10 is perferably maintained between about an [40 and 210 fahrenheit while the normal time required for each bag to pass through the chamber 10 is from about 3 to 5 minutes.  
  Each bag is moved through the steam chamber and is directed along a zig-zag path of travel which includes moving the bag successively upwardly and downwardly while rolling the bags during each successive downward movement and rotating the bags for a predetermined period of time immediately following each downward movement and preceeding the next upward movement of the bags. As the bags are passed through the steam chamber, they are maintained in a horizontal plane rel ative to their longitudinal axis and their longitudinal axis is maintained at right angles to their path of travel through the steam chamber. Each of the bags passing through the steam chamber follows the same path of travel and an identical treatment so that the loose mass of yarn inside each bag is uniformly bulked as it is passed through the steam chamber. After the bags are removed from the steam chamber, they may be placed in an autoclave and heat-set under pressure, if desired.  
  In the drawings and specification there has been set forth a preferred embodiment of the invention, and although specific terms are employed, they are used in a generic and descriptive sense only and not for purposes of limitation.  
 That which is claimed is:  
  1. An apparatus for heating thermoplastic yarn in elongate perforate bags, said apparatus comprising a. an elongate chamber including entrance and exit ends,  
 b. means for creating a steam atmosphere in said chamber,  
 c. an endless conveyor having an upper reach extending through said chamber, said conveyor having entrance and exit end portions extending outwardly from the corresponding entrance and exit ends of said chamber,  
 d. drive means for imparting movement to said conveyor,  
 e. guide means for moving said upper reach of said conveyor in a zig-zag path of travel through said chamber to provide a series of upwardly and downwardly inclined sections providing successive peaks and valleys along said upper reach of said conveyor, and  
 f. carrier means spaced along said conveyor for engaging the elongate bags laid on the entrance end portion and across said conveyor and for moving the bags into, through and out the exit end of said chamber, said carrier means moving the bags up successive upwardly inclined sections and permitting the bags to roll down the adjacent downwardly inclined sections to remain in the corresponding valleys and be rotated by said conveyor until again engaged by said carrier means to be moved up the next successive upwardly inclined section.  
  2. An apparatus according to claim I wherein said means (b) includes steam pipes spaced along said chamber and adjacent said upper reach of said conveyor.  
  3. An apparatus according to claim 2 wherein said steam pipes are spaced above and below said upper reach of said conveyor.  
  4. An apparatus according to claim 3 wherein said steam pipes spaced below said upper reach of said conveyor include pipe sections extending transversely of said chamber, each of said pipe sections being equally spaced below the successive peaks and valleys of said upper reach of said conveyor.  
  5. An apparatus according to claim 4 wherein said steam pipe above said upper reach of said conveyor follows a sinuous path from one end of said chamber to the other 6. An apparatus according to claim 5 including an inverted V-shaped baffle plate extending from one end of said chamber to the other and being positioned between said upper reach of said conveyor and said steam pipe said baffle plate being of sufficient width to direct condensation down opposite sides of said chamber and to prevent direct contact of the condensation with the bags passing through said chamber.  
  7. An apparatus according to claim 4 wherein said pipe sections below said upper reach of said conveyor are divided into separate zones along the length of said cham ber. and including valve means for controlling the operation of each zone to thereby vary the heating of the bags passing through corresponding areas of said chamber.  
  8. An apparatus according to claim 1 wherein said conveyor comprises a pair of spaced apart sprocket chains, and connecting slats connected at opposite ends to said chains and extending therebetween, the spacing between said slats being less than the diameter of the bags so that the bags are supported by said slats.  
  9. An apparatus according to claim 8 wherein said carrier means comprises semi-circular carrier plates connected at their lower edges to said slats and extending upwardly therefrom with the inwardly bowed portions thereof extending in the opposite direction from the direction of movement of said conveyor, and the distance from one edge to the other of said carrier plates being slightly greater than the diameter of the bags.  
 10. A method of heating thermoplastic yarn in elongate perforate bags comprising the steps of a. passing successive bags through a horizontally disposed elongate steam chamber, and while b. directing the bags along a zig-zag path of travel through said chamber which includes moving the bags successively upwardly and downwardly,  
 c. rolling the bags during each successive downward movement, and  
 d. rotating the bags for a predetermined period of time immediately following each downward movement and preceding each upward movement of the bags.  
 11. A method of heating thermoplastic yarn in elon gate perforate bags comprising the steps of a passing successive bags through a horizontally disposed elongate steam chamber. and while b maintaining the bags in a horizontal plane relative to their longitudinal axis and maintaining their longitudinal axis at right angles to their path of travel through said steam chamber.  
 c. successively raising the bags upwardly at spacedapart intervals during their path of travel through said steam chamber,  
 d. successively rolling the bags downwardly immediately following the raising of the bags in step t c), and  
 e. maintaining the bags at the same level while rotating the bags at this level for a predetermined period of time immediately following the downward rolling of the bags and preceding the upward raising of the bags.