US2060515A - Treatment of cellulose filaments - Google Patents

Description

l Nov. 10, 1936. T. MCCONNELL TREATMENT OF CELLULOSE FILAMENTS Filed Feb. l5, 1935 2 Sheets-Sheet 1 Nov. 1o, 1936. T, MCCONNELL 2,060,515

TREATMENT OF CELLULOSE FILAMENTS Filed Feb. l5, 1955 2 Sheets-Sheet 2 ecenneeaaeeggo Patented Nov. 1.0, 1936 UNITED STATES 2,060,515 TREATMENT or cELLULosE FILAMENTS Thomas- McConnell, Northampton, Mass., as-

signor to Hampton Company,' Easthampton,

Mass., a corporationvof Massachusetts Application February 15, 1935, Serial No. 6,664

1 Claim.

One of the objects of my invention is the drying of various natural and artificial laments and mixtures of the same, in the bleached, unbleached, dyed, undyed, softened, unsoftened or other form, when said filaments or filamentous material is in the hank, skein, bobbin, spool, cake or other form wherein the filaments are in the aggregated condition, the drying operation comprising circulation of air through the same from the center towards the periphery, that is, from the inside outwards, the re-use of air so employed, and the addition of a determined amount of moisture to the dried cellulosic material in predetermined amount as by a humidication treatment in the same apparatus as employed in the drying operation, and without handling the cellulose material between the drying and the humidifying step.

Another object of my invention is the removal of moisture from various forms of cellulose with varying amounts of water contained therein, at the minimum temperature and elapse of time consistent with preservation of the original color of the cellulose material, that is, with uncolored cellulose, to conserve the whiteness to the maximum degree, and still economize in the drying operation as to time and heat loss.

Another object is the conservation of removal of excess moisture and to humidify aggregates of cellulosic filaments or filaments composed partially of cellulose, either in the natural or articial state, whether esterified, de-esterified, or etheried, or partially so, when formed upon, wound around or reeled into hanks, skeins, or on to bobbins and/or spools, or when present in the cake form as is obtained by the centrifugal method of artificial filament formation, especially in connection with the production of rayon, as by the viscose process.

The moisture removal step may be separate from, or succeeded by a humidifying step wherein an amount of moisture may be introduced equivalent to normalv allowable moisture regain for the particular class of goods operated upon, by virtue of the passage of heated air through the filamentous cellulosic mass by means of mechanical arrangement, a preferred form of which is ,disclosed in the drawings attached hereto, in

sizes, sequences of parts and' relative arrangement of units being variables, depending upon the temperature desired to be employed, the normal drying period required, the time desired in the humidifying operation, the nature of material dried, its compactness and condition during the 5 operation of. moisture removal and regain, and other factors, as will bewell understood by those versed in the art to which this invention appertains.

For purposes of clarity insofar as the description of this invention is concerned, cellulosic material in bobbin or spool form is to be considered as aggregates of filaments, usually of indeterminate length, placed on a core of paper, wood, metal or the like, which core has a multipliclty of holes, slots, slits or other orifices of desired size and shape therein. Cellulosic material in hank or skein form is a plurality of cellulosic filaments reeled into circular form with no supporting core or other interior. Cakes are similar to skeins, only the circumference is usually much less, an example of a cake coming withinthe scope of this invention being the filament aggregates formed in the production of rayon by the viscose process wherein a centrifugal box is employed in which the formed filaments after setting or coagulating are wound up. There is usually no supporting core in a viscose rayon oak as comprised in this invention.

In general, the drier and humidifier of my invention comprises an induction motor driven blower, unit heaters, an air conditioning section or unit, a plurality of drying compartments of which four are shown in the drawings, together with the necessary duct-work, dampers, .temperature control panels, valves, piping, etc. One of the main purposes of the same is to remove moisture from wet rayon cakes as received from the package process department, especially cakes produced by the process of centrifugal or pot spinning Ias carried out in lament formation from viscose as raw material.

At the completion of the drying step the cakes may be removed, or they may, without further handling, be submitted to a humidiflcation treatment, details of which follow:-

In a description of one preferred mode of operation, a blower I (Fig. 1) driven by leather or other belt from motor 2, drives air admitted to blower at room temperature through a lterscreen box 3. Air is discharged from blower through a duct 4 into a heater section 5, the latter containing four unit heaters 6. From 6 onward, the main air duct is divided into four separate ducts l, 8, 9 and I0. In the air-conditioning section II, are located two spray nozzles I 2 in each of the individual air ducts. Individual dampers I3 are located in each duct.

From the ducts, air flows to the four wind lboxes 60 I4, I5, I6 and I1, which are located at the rear of the drying compartments I8, I9, 20 and 2l respectively. In the drying compartment cakes of partially hydrated cellulose or rayon 22 are supported on horizontal metallic tubes of perforated metal 23, the perforations being of size, shape and spacing as desired. It will be noted from a comparison of Figs. 1 and 2 that the central ducts 8 and 9 extend longitudinally beyond the outer ducts. 'Ihe wind boxes I4 and I5 are coupled to the outer ducts 1 and I0 and the wind boxes I6 and I1 are coupled to the inner ducts 8 and 3. The drying compartments on each side are preferably arranged in line with each other for convenience in placing and removing the cakes. Each drying compartment is provided with doors 40 arranged to provide full access to the interiorvof the compartment when it is desired to handle the cakes or to have the heated air pass out through them, and to close the compartments so that the exterior of the cakes as well as their interiors will be subjected to heat as is preferable during the drying and conditioning operations.

The supporting tubes are rigidly secured to the rear wall of the drying compartment. Through a hole for each tube in this wall air is admitted directly to the inside of each perforated tube, whence it passes through the cakes and is dissipated from the drying compartment by leakage, as through a louvre or plurality of louvres in the top.

The free end of each perforated tube 23 (Fig. 3) is plugged, as by means of a blank plate 34, which is preferably centered by a perforated metallic tube of external diameter slightly less than the internal diameter of the tube, so that a tight union results, thus constituting a closely fitting plug to minimize escape of heated air.

The temperature and humidity control of the air passing through the apparatus may be accomplished in/ known manner, either manual or automatic, as, for example, through steam valves 25, 26, 21 and 28, each of which controls the steam iiow to unit heaters. The thermo-couples of the controllers are located in the individual ducts at 29, 30, 3l and 32, of Fig. 1. v

Water is supplied to spray nozzles I2 in any desired manner. nished as indicated in Fig. 1, to the heads, where it comes in contact with moisture to induce humidication. All duct work, wind boxes, drying compartments and supporting arms are preferably made of galvanized iron sheets or other suitable material, properly insulated where necessary.

In Fig. 4 a modified ange is shown suitable for the drying and humidifying on spools and/or bobbins,A whereby positive pressure may be apscoping within support tube 23. Plug 35 carries a short radial pin 36 which co-operates with a bayonet cam slot 31 in end of support tube 23.

In the drying, or drying and humidifying of cellulosic material in cake or similar form, the cake 22 usually saturated with moisture, is placed on tube 23, and when 23 is lled with cakes, blank end 34, is adjusted so the cakes fit tightly one against the other. Heated air issues through perforations in 23, tending by forcing said air from a center outward to expand and loosen up the cake, and thereby minimize period of drying. As a specific example, a cake as made by the viscose process of regenerated cellulose formation by Compressed air is also furthe centrifugal spinning method, at a temperature of y180" F. will pass to the bone dry condition in about 6 hours drying period, in comparison to 30 to 40 hours drying in the usual oven method. At the close of the drying period, moisture as shown in the drawings is admitted to the air, the temperature of airladen moisture being preferably in the neighborhood of 100 F. A humidifying period of one-half to two hours, covers the range of cellulosic material to be dehumidied in this apparatus, assumingV a moisture regain of r1% to 10% is desired.

In the drying of hanks, tube 23 is of such size that the hanks or skeins will closely t thereon, and the process is carried out in a general manner as for the drying of cakes. Skeins may be humidied after drying in a manner similar to the treatment of cakes.

In the drying or drying and humidiflcation of cellulosic material in bobbin or spool form, the bobbin or spool, as of metal or metal covered with synthetic resin or other lacquer or protective medium, is perforated in any suitable manner, has sides preferably closely tting and smooth to minimize escape of air between spools.

The tube 23 (Fig. 4) is lled with spools and quickly fastened together or tightened by means of the device 3, 35, 36, 31, or other suitable device. Likewise the drying and humidifying operations proceed from the center to the periphery of the cellulosic material, the same is expanded during passage of air, and the drying operation greatly facilitated over drying of similar material of the older art. Passage of air at the temperature desired is continued until the degree of dryness required is attained, after which the required moisture regain is obtained by method as above described.

Where recirculation is desired it may be accomplished through ducts 38 and 39 (Fig. 1) which as shown in Fig. 2 are located along the tops of the drying compartments and are in communication therewith through louvres 4I. Dampers 42 in these recirculating ducts permit them to be closed oif to thel extent desired. The ducts converge, as appears in Fig. 1, into the lter 3 attached to the intake of the blower I.

What I claim ist- A drying apparatus for rayon cakes comprising a plurality of rows of discrete drying compartments arranged back to back, ducts passing between the compartments and associated one with each compartment, a plurality of horizontally extending perforated tubes located in each compartment and connected to the associated duct, means for conning rayon cakes on said tubes to constrain air passingthrough the tubes to permeate Ithe body of the cakes, means for forcing air under pressure through said ducts and tubes, means for controlling the temperature and humidity conditions of said air, means for controlling the ilow of air through each duct independently of the other ducts, a door on that side of each compartment adjacent to the ends of the perforated tubes and mounted to permit free access to all said tubes'and to permit escape of any desired amount of heated air from the compartment while maintaining a heated atmosphere around the cakes, and ducts connected with the upper portions of the compartments and with the forcing means to cause recirculation of a desired amount of the air.

THOMAS Muccornmit.

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