US2986912A - Textile treating apparatus - Google Patents

Description

June 6, 1961 J. P. RICHESON ETAL 2,986,912

TEXTILE TREATING APPARATUS Filed April 14, 1958 IN V EN TORS JAMES P R/CHESO/V ROB IQTCJAC'KSO/V 4% F765.

4171311 ATTORNEYS U i d States Pa e 2,986,912 TEXTILE TREATING APPARATUS James P. Richeson and Robert C. Jackson, Decatur, Ala., assignors to The Chemstrand Corporation, Decatur, Ala., a corporation of Delaware Filed Apr. 14, 1958, Ser. No. 728,460 4 Claims. (Cl. 68-5) This invention relates to textile treating apparatus and more particularly to an apparatus for conditioning a tow of filamentary material formed from a synthetic composition such as acrylonit-rile polymers or the like with a pressurized fluid such as steam.

Much of the textile industry today is devoted tothe production of synthetic filaments and fibers which are formed from such synthetic material as acrylonitrile polymers or the like. In one operation for spinning acrylic material for instance, the material is spun by a wet spinning process into a plurality of continuous filaments which form what is generally termed a filamentary tow. During the subsequent processing of this continuous filamentary tow, it is subjected to various conditioning operations one of which involves stretching or elongating the tow filaments so as to orient the molecules and impart certain highly desirable physical characteristics to the filaments such as high tensile strength. Although these stretched filaments possess excellent physical properties when formed into yarn and, in turn, fabrics, they are prone to fibrillate or spilt ofi into fibrills when subjected to abrasion. This fibrillation causes abraded portions of the fabric to appear lighter in color than the remaining portion giving the illusion of wear. It is thought that the fibrillation results from the internally strained condition of the molecular structure of the filaments created during the stretching operation. It has been found that this fibrillation can be reduced or substantial-1y eliminated by heat-relaxing or annealing the tow and this annealing operation may be carried out by subjecting the tow to a high temperature medium capable of wetting the polymer structure. For instance, in one widely used annealing operation, high temperature steam in a wet condition and under pressure is applied to the tow while the tow is positioned in a substantially relaxed or tension-free condition. When the filaments are heated in this relaxed condition, the filament molecules are oriented with resulting shrinkage of the filaments and the tendency of the filaments to fibrillate is virtually eliminated.

In one widely used type of apparatus for carrying out this annealing operation, the tow was processed in a batchtype operation which involved loading large quantities of tow material into autoclaves or similar pressure vessels wherein it was subjected to steam under pressure for an extended period of time while in a relaxed condition. It can be understood that such a batch-type annealing operation is time consuming and is generally expensive from the standpoint of both time and labor expended as well as the initial investment in the bulky apparatus required.

1 As the filamentary tow is produced in a continuous strip form, it has been suggested that a continuous type of annealing operation would be of exceptional advantage commercially, both from the standpoint of cost and quality. However, continuous annealing of tow presents many problems heretofore insurmountable as a result of such limiting factors as the high speed at which the tow is advanced in conventional equipment. Even more of a problem is presented when the tow is to be subjected to high pressure steam. When high pressure steam is the annealing medium, the tow must move continuously through a region of high pressure while in a relaxed condition so as to be contacted by the steam and permit the effective carrying out of the annealing operation. Therefore, maintaining this high pressure region in a substantially sealed state while the tow passes through presents a serious structural limitation.

Accordingly, a primary object of this invention is to provide a new and novel apparatus for the treatment of textile material.

Another object of this invention is to provide such an apparatus for continuously annealing a tow of filamentary material formed from a synthetic composition such as acrylonitrile polymers and the like.

A further object of this invention is to provide a new and novel apparatus for treating continuous material with a pressurized fluid.

This invention further contemplates the provision of a new and novel apparatus for continuously conveying a filamentary tow of synthetic material formed from a composition such as acrylonitrile polymer and the like through a substantially sealed chamber containing steam at a relatively high temperature and pressure so that, while the tow is in the chamber in a relaxed condition, it is subjected to the steam and subsequently removed therefrom in an annealed condition.

A still further object of this invention is to provide a new and novel apparatus for continuously annealing a filamentary tow which eliminates any contamina tion or-physical deterioration of the tow during annealing to give an annealed product of relatively high quality.

Still another object of this invention is to provide a new and novel apparatus for annealing acrylic tow which is simple in construction, virtually eliminates any discharge of steam into the surrounding atmosphere, and which automatically performs an annealing operation in a highly efficient manner for prolonged periods of time without danger of breakdown.

. Other objects and advantages of the invention will become apparent from the following description taken in connection with the accompanying drawing.

The objects of the invention and other related objects are accomplished generally by providing a conditioning chamber of substantially sealed construction containing a pressurized fluid such as steam. Pressurized steam at a relatively high temperature and in a wet or saturated con-. dition is supplied to the chamber for carrying out a heatrelaxing or annealing operation on a tow of filamentary material formed from a synthetic composition such as acrylonitrile polymers or the like. In order to convey the tow through the chamber, feeding means are associated with the container which continuously move the filamentary material into the chamber where it is received by conveying means in the chamber interior. The advancing filamentary tow stacks or distributes itself on'the conveying means so that it is maintained in a substantially tension-free or relaxed condition for a predetermined length of time and is subjected to the high temperature steam within the chamber, so that annealing is accomplished. Means are also associated with the chamber for removing the tow from the conveying means inside the chamber to the chamber exterior subsequent to the completion of the annealing operation.

The novel features which are believed to be characteristic of the invention are set forth with particularity in the appended claims. The invention itself, however, both as to its organization and method of operation, may be best understood by reference to the following description taken in conjunction with the accompanying drawing in which: I

FIGURE 1 is a diagrammatic view of an annealing apparatus constructed in accordance with the invention;

FIGURE 2 is a sectional view taken substantially along line 2-2 of FIGURE 1 in the direction of the arrows; and

FIGURE 3 is a sectional view taken substantially along line 3--3 of FIGURE 1.

Referring now to FIGURE 1, there is shown a material treating apparatus constructed in accordance with the invention which is utilized to treat continuously moving material with a fluid medium maintained at a relatively high pressure. It should be understood that although the apparatus of FIGURE 1 may be employed to treat any desired type of material with any suitable type of fiuid medium, it is particularly useful in the heatrelaxing or annealing of filamentary material composed of a synthetic composition such as acrylonitrile polymers and the like, and it is for carrying out such an operation that the apparatus of the invention will be described hereinafter.

In the embodiment of FIGURES l-3, a tow designated by the numeral 11, has been provided which is composed of a plurality of continuous filaments of acrylic material Which have been freshly formed and are in an internally strained condition as a result of a previously carried out molecular orientation-treatment such as stretching or the like.

In, accordance with the novel arrangement of the invention, means have been provided to heat-relax or anneal the internally strained filaments of this tow 11 as it is advanced in order to relieve the molecular strains and eliminate the problem of fibrillation common to Wet spun acrylic tow. Furthermore, the novel means of the invention permit a continuously moving tow of indefinite length to be subjected to such an annealing operation.

More specifically, there has been provided a conditioning chamber 12 which may be of any suitable shape such as that shown in FIGURES l-3. The chamber :12 contains an interior 13 which may be filled with a fluid medium such as steam for carrying out the tow annealing operation discussed above.

In order to advance the tow 11 into the chamber '12, tow feeding means, designated generally by the numeral 14, have been provided which are preferably positioned as shown in association with the upper or top wall 16 of chamber 12. More specifically, the towfeeding means 14 comprise a pair of cooperating continuous webs or belts 17, 18, each of which is mounted on a pair of driving rolls 19, 21. Each pair of rolls 19, 21 is arranged to be driven by any suitable means (not shown) or if desired one of the rolls may be driven with the other roll arranged as an idler. As shown in FIGURE 1, rolls 19, 21 are positioned on opposite sides of the chamber wall 16 with the belts 17, 18 extending through suitably spaced wall openings 22. In this manner, the belts 17, 18 may be driven to move the tow 11 in sandwiched relationship with the cooperating portions of the belts and feed the tow continuously into the interior 13 of the conditioning chamber 12.

In order to reduce or substantially eliminate any leakage or loss of pressure from the chamber interior 13 through the wall openings 22, any suitable pressure device such as a labyrinth seal or resilient sleeve designated generally by the numeral 23 is suitably positioned adjacent each of the wall openings 22. The belts and the tow 11 may then move continuously through the openings 22 and the sealing devices 23 while the chamber 12 is maintained in a substantially sealed position. Preferably, the sealing device 23 is of the type disclosed and claimed in the copending patent applications of each of the present applicants, Serial No. 728,459, filed Apr. 14, 1958, by Robert C. Jackson and Serial No. 728,461, filed Apr. 14, 195 8 by- James P. Richeson.

As has been previously described, in theprocessing of tow composed of wet spun acrylic material, a heatrelaxing or annealing step is often required to relieve internally strained filaments and to obtain a tow having commercially acceptable physical characteristics. Such an annealing step is generally carried out by subjecting the filamentary tow to a heated fluid medium such as 4 saturated or wet steam under pressure while the tow is in a'substantially tension-free or relaxed condition. Conveying means, therefore, have been provided for positioning the tow 11 fed to the chamber interior 13 in a substantially relaxed condition while being subjected to treatment by steam.

More specifically, a continuous belt 24 is disposed within the lower portion of the chamber interior 13 as shown in Figure 1 and is mounted on rolls '26, 27, 28, so that its upper portion is driven in the direction of arrow I. Thus, the belt 24 is arranged to provide a continuously moving, horizontal surface 29 on which the tow is deposited as it gravitates or falls from the nip of the. rolls 21 in the .tow feeding means 14.

As shown in FIGURE 1, rolls 26, 27 are positioned within the interior 13 of chamber '12 and roll 28 is positioned on the exterior of the chamber so that the belt 24 moves through openings 31 in the side wall 32 of the chamber 12. As shown in FIGURES l, 3, the belt 24 is positioned so as to cooperate with an upper belt 33 of relatively short length and form means, designated generally by the. numeral 30, for moving the annealed tow 11 out of the chamber 12. The upper belt 33 is suitably mounted on rolls 34, 36 which are driven in any suitable manner so as to move the upper belt 33 at the same linear speed as the elongated lower belt 24. As can be seen, roll 34 is mounted so as to cooperate with roll 27 and roll 36 with roll 28 whereby tow 11 is sandwiched between the overlying portions of the belts 24, 33 and conveyed to the exterior of the chamber 12 through the centrally arranged opening 31.

As previously described, the wall openings 31 are provided with suitable sealing devices, designated generally by the numeral 37, which are preferably similar to those associated with the wall openings 22 so as to maintain the pressure in chamber 12 and prevent the leakage of steam through the wall openings 31.

As previously discussed, the interior 13 of chamber 12 is supplied with steam in order to bring the tow 11 to an annealing temperature of between approximately to C. It has been found that a steam pressure between 35 to 50 pounds per square inch gives satisfactory results. Furthermore, it should be understood that the steam is preferably of low quality for facilitating the annealing treatment.

In order to introduce steam under pressure to the chamber interior 13, suitable inlet means have been provided in the chamber upper wall 16 such as a fitting 38 which, of course, is preferably provided with a check valve or a similar device to facilitate the admission of steam.

In order that the tow annealing operation be carried out with a minimum of turbulence which would generally result from the introduction of high pressure steam into the chamber 12, a screen 39 may also be positioned as shown. in FIGURE 1 by any suitable means on the inner surface of the inclined portion of wall 16 adjacent fitting 38. Thus, the steam passing through fitting 38 into the chamber interior 13 is reduced to a relatively non-turbulent condition.

In the operation of the annealing apparatus, of the invention, the tow 11 is continuously fed into the chamber interior 13 through the top wall 16 by means of belts 17, 18 so that it gravitates, as shown best in FIGURE 1, onto the moving upper surface 29 of belt 24. As belt 24 is driven continuously, the tow 11 distributes itself along the moving surface 29 as shown best in FIGURE 3, so that successive portions of its length are continuously maintained for a predetermined period of time in a sub stantially relaxed condition. As the steam flows through the fitting 38, it fills the chamber 13 so that the tow distributed along the belt surface 29 is heated and moistenedby the steam as the tow moves across the chamber interior in a relaxed condition on the belt 24.

Thus, as is well known, the internally strained filaments of the tow are heat-relaxed and the tow is in a completely annealed condition as it enters the nip of the rolls 27, 34. As the tow is picked up by the rolls 27, 34, it is sandwiched between the belts 24, 33, as described above, and carried out of chamber 12 through the centrally arranged wall opening 31 and cooperating sealing device 37 so that it may be subsequently collected and further processed in any desired manner.

As the tow is annealed, filament shrinkage, of course, will occur and thus the speed of the rolls which drive belts 24, 33 should be somewhat lower than the speed of the rolls which drive the belts of the tow feeding means 14 to compensate for this shrinkage. For instance, acrylic tow fed to the interior 13 of chamber 12 at a rate of 150 feet per minute is withdrawn in the annealed condition from the chamber at a rate of approximately 105 feet per minute.

In the preferred embodiment, the rate at which the tow is deposited on the moving surface 29 of belt 24 is regulated by any suitable means responsive to the movement of the tow. For instance, tow speed monitoring means such as photoelectric cells 41, 42, are suitably positioned within the chamber interior 13 so that their associated light sources (not shown) may be interrupted by the reach of tow between the rolls 21 and the upper surface 29 of belt 24 when the tow is underfed or overfed. As should be understood, the cells 41, 42 may be arranged in any suitable manner to control the speed of the tow feeding means 14 or the tow removal means 30. In one arrangement, cell 41, when its light source is interrupted, acts to reduce the speed of belts 17, 18, and cell 42, when its beam is interrupted, to increase the speed of belts 17, 18. As a-result, the continuously moving tow 11 remains generally in the range of positions defined by the two cells 41, 42, as shown in the drawing. Condensed steam in the chamber interior 13 may be removed by means such as an outlet fitting 43 (FIG. 1) in which a suitable steam trap may be positioned.

It can be seen that with the novel construction of the invention, filamentary tow or any other similar material may be continuously subjected to a pressurized fluid medium such as the apparatus of the invention is particularly suitable for treating wet spun acrylic tow and permits such a tow to be efficiently heat-relaxed or annealed in a simple or easy manner. The annealing operation is completely automatic and the novel construction of the invention permits control of the annealing conditions over a wide range in accordance with the type of tow processed. Another of the outstanding features of the invention is that the container through which the tow is passed is maintained in a sealed condition to not only eliminate a source of annoyance caused by continually leaking steam, but also to enable the annealing conditions within the chamber to be accurately maintained at a predetermined level. The tow is smoothly and rapidly moved through the annealing chamber with a minimum of change in form so that contamination of the tow is prevented and an annealed tow of high quality emerges from the chamber at the completion of the operation.

While there has been described what at present is considered to be the preferred embodiment of the invention, it will be understood by those skilled in the art that various changes and modifications may be made therein without departing from the invention and, therefore, it is the aim of the appended claims to cover allsuch changes and modifications as fall within the true spirit and scope of the invention.

Having thus described the invention, what is claimed is:

1. Apparatus for treating a tow of filamentary material comprising, in combination, a conditioning chamber having a top wall and side wall, means for supplying pressurized steam to said chamber, a pair of endless belts having engaging spans for cooperating to receive the tow therebetween and feed said tow into the interior of said chamber through said top wall, pressure sealing means mounted on the top wall of said chamber adjacent to and in contact with said pair of cooperating belts, a horizontal ly disposed endless belt drivably positioned in said chainber and extending through the side wall thereof for receiving tow from said cooperating belts, said horizontally disposed belt being arranged to convey said tow through the interior of said chamber in a relaxed condition whereby said tow is subjected to said steam, an endless belt mounted on the chamber and having a span engaging a portion of said horizontally disposed belt for cooperating with said horizontally disposed belt to hold the tow therebetween and convey said tow through said chamber side wall, pressure sealing means mounted on said chamber side wall adjacent to and in contact with said horizontally disposed belt and said belt cooperatively arranged therewith, photoelectrically operated means mounted on the inside wall of said chamber adjacent to said pair of cooperating belts arranged to feed said tow into said chamber for monitoring the rate at which said tow is deposited on said horizontally disposed belt, and means for moving said belts.

2. Apparatus for treating a tow of filamentary material, comprising a conditioning chamber, means for supplying pressurized steam to said chamber, a pair of endless belts mounted on the chamber and extending through a wall thereof, said endless belts having engaging spans for cooperating to hold the filamentary material therebetween and feed said material into the chamber, sealing means mounted on the chamber adjacent to the endless belts for maintaining the chamber in a substantially sealed condition, a second pair of endless belts mounted on the chamber and extending through a second wall thereof, said second pair of endless belts having engaging spans for cooperating to hold the filamentary material therebetween and removing said material from the chamber, sealing means mounted on the chamber adjacent to the second pair of endless belts for maintaining the chamber in a substantially sealed condition, one of said second pair of endless belts extending into a position to receive the filamentary material from the first pair of endless belts and to convey said material in a substantially relaxed condition between the cooperating spans of said second pair of endless belts, and means to move said pairs of endless belts.

3. An apparatus for treating a continuous tow, comprising a closed conditioning chamber, a first pair of endless belts mounted on the chamber, said first pair of endless belts extending through a wall of the chamber and having engaging spans for cooperating to hold the tow therebetween and advance the tow into the chamber, sealing means on the chamber adjacent to the first pair of endless belts for maintaining the chamber in a substantially sealed condition, a second pair of endless belts mounted on the chamber and extending through a wall thereof, said second pair of endless belts having engaging spans for cooperating to hold the tow therebetween and remove said tow from the chamber, one of said second pair of endless belts extending to a position beneath the first pair of endless belts for receiving the tow from said first pair of endless belts and conveying said tow in a substantially relaxed condition into engagement with the other belt of said second pair of endless belts sealing means on the chamber adjacent to the second pair of endless belts for maintaining the chamber in a substantially sealed condition and means for moving the belts.

4. An apparatus for treating a continuous tow, comprising a closed conditioning chamber, inlet means for introducing steam into the chamber, a screen mounted inside the chamber adjacent to the inlet means for dispersing the steam and preventing turbulence, a first pair of endless belts mounted on the chamber and extending through a wall thereof, said first pair of endless belts having engaging spans for cooperating to hold the tow therebetween and feed the tow into the chamber, sealing means on the chamber adjacent to the first pair of endless belts for maintaining said chamber in a substantially sealed condition, a third endless belt mounted on the chamber and extending through a wall thereof, said third endless belt being positioned beneath the first pair of endless belts for receiving the tow from said firstpair of endless belts and conveying the tow across the chamber in a substantially relaxed condition, a fourth endless belt mounted on the chamber adjacent to the third endless belt andhaving a span engaging a portion of the third endless belt for cooperating to hold the tow therehetween and carry said tow through the wall of the chamber, sealing means on the chamber adjacent to the third and fourth belts for maintaining the chamber in a substantially sealed condition, and means for moving the belts.

References Cited in the file of this patent UNITED STATES PATENTS 8 Gadd Mar. 2, 1897 'Seither Nov. 5, 1901 Hebden Mar. 4, 1902 Fish Mar. 6, 1906 Cobb Oct. 23, 1928 Ward Sept. 3, 1929 Depew Nov. 26,1935 Clark Feb. 4, 1 936 Woodhead June 22, 1937 Andrews Mar. 17, 1942 Schrenk June 27, 1950 Pendleton Apr. 14, 1953 Eriksson Dec. 24, 1957 FOREIGN PATENTS Germany Nov. 3, 1934

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