US2589400A - Drying apparatus - Google Patents

Description

Marh 18, 1952 F. w. KosTER ET AL DRYING APPARATUS 2 SHEETS-SHEET l Original Filed April 19, 1945 INVENTORS. FEEDER/CK W. K'STER L OUJ` A. BEL Y BY C ,6.

ATTORNEY.

March 18, 1952 F. w. KosTER ET AL DRYING APPARATUS 2 SHEETS--SHEET 2 Original Filed April 19, 1945 -jOu-- INVENTORS. W. KOSTER oaf/nv BY VI/g Q, m

FREDERICK LOU/ A A T'TRNE Y.

ratented Mar. 18, 1952 DRYIN G APPARATUS Frederick W. Koster, Wallingford, Pa., and Louis A. Oberly, Twinsburg, Ohio, assignors to American Viscose Corporation, Wilmington, Del., a

corporation of Delaware Original application April 19, 1945, Serial No. 589,200. Divided and this application January 21, 1949, Serial No. 71,806

Claims.

This invention relates to apparatus for drying parcelsof lamentary material and the like, such as wound packages of rayon. This application is a division of application Serial No. 589,200, filed April 19, 1945, now Patent 2,485,609.

Itis an object of the present invention to provide an improved drying apparatus utilizing the dielectric characteristics of the materials to be dried for developing the heat internally thereof in which the parcels to be dried are carried by a foraminous support which is moved in a cyclical path along a portion of which a high frequency electric field is developed and maintained, while at the same time passing a current of heated gaseous medium, such as air, upwardly through the foraminous support and above the parcels being dried to facilitate the removal of moisture vaporized by the dielectric heating and to prevent condensation of the vaporized moisture on adjacent surfaces of the apparatus, such as the electrodes, their supports, and the housingthrough which the foraminous support moves. Other objects and advantages of the invention will be apparent from the drawing and the description thereof hereinafter.

In the drawing illustrative of the invention,

Figure 1 is a plan view, with part of the housing removed of one embodiment of the invention,

Figure 2 is an elevation of the embodiment of Figure 1,

. Figure 3 is a plan view, with part of the housing removed, of a modification,

Figure 4Y is a cross-sectional elevation of the embodiment of Figure 3.

As shown in Figures 1 and 2, an annular foraminous belt or platform 2, such as of open mesh metallic screen material is rotated about its axis by the supporting conical rolls 3 which are driven by the pinions 4 arranged inside the annular belt which mesh with the annular gear 5 carried by the central shaft 6 mounted for rotation by means of a motor I therebelow. The shaft carries in spider-like arrangement a plurality of outwardly extending arms 18 which have projections 9 thereof hinged at points I0 and II. Individual electrodes I 2, preferably of foraminous material, such as metallic screening, are suspended pivotally from the outer ends of the respective projections from the arms of the spider,

v sothat the electrodes are arranged above the v annular foraminous belt 2.

The upper portion of the shaft 6 carrying the spider 5 is of metal butis insulated by an intermediate section I3 from the lower portion of the shaft extending to the motor 1. A brush Il bears against the upper metallic portion of the shaft and is connected by a lead I5 to one pole I6 of a high frequency oscillator II, such as a radio frequency oscillator. The arms, projections and suspensions to the individual electrodes are all of metallic construction, so that the brush serves to connect each of such electrodes with the same pole of the oscillator. The other pole I8 of the oscillator is preferably grounded and the annular foraminous belt is also grounded at I9 so it will constitute a co-operating electrode with respect to the upper individual electrodes. Beneath the annular belt 2 there is arranged a vduct 20, preferably of annular shape having discharge openings 2| in the upper surface thereof. One end of the duct is connected to a chamber 22 adapted to receive a heating element 23, such as a steam coil, electric coil or the like, so that air entering the duct is heated thereby. A fan 24 may be provided in the chamber to force the air into the duct. A housing 25 is provided about the assembly and the roof may slope upwardly to the center thereof to which the discharge duct 26 may be connested to a fan 21 for inducing a draft therethrough. The housing is provided with an opening 28 in the peripheral wall, so that the annular belt is accessible to an operator for introducing and removing the parcels of material to be dried. Preferably the opening is of such height as to allow plenty of room for the size of the parcels 3l to be handled and it is provided with a back wall 29 just behind the annular belt which may be supported by a bottom and ceiling walls extending inwardly from the lower and upper edges of the opening. A stationary cam 30 is arranged above the charging opening in the path of the hinged projections 9 from which the electrodes I2 are pivotally suspended so that as they are brought into proximity to the opening, the upper electrodes are lifted from the parcels 3| and proceed over the ceiling of the opening and then descend into contact with the parcels beyond the charging opening. In this fashion, the operator is protected from any substantial iniiuence of the high frequency electric eld.

In operation of the embodiment of Figures 1 and 2, the motor rotates the shaft which effects travel of the annular foraminous belt and the electrodes at the same speed in a cyclical path. part of which extends through the charging opening. As the annular foraminous support passes through the charging opening, the parcels of material to be dried may be placed upon the support either mechanically or manually and similarly these parcels which have passed through the housing may be discharged from the support either manually or mechanically. The characteristics of the oscillator may be adjusted to give any desired heating effect internally of the parcels depending upon the particular nature thereof. The temperature of the air which is forced upwardly through the foraminous support is also controlled in accordance with the material under consideration. For example, where woundV packages, such as cakes of regenerated cellulose filaments, such as those obtained from viscose, are being dried, the temperature of Vthe air may be from about 140 to 170 F., whereas the temperature developed internally of the cake by the electric field may be about the same as that of the air or higher, such as up to substantially 212 F. The passage of the heated air through the housing, which may be insulated advantageously, serves to prevent condensation -on the walls thereof Vand on the upper electrodes and the suspensions thereof, thereby preventing Vdrippings back upon the parcel being dried, conserving heat and increasing the uniformity of drying effect.

As shown in Figures 3 and 4, a similar housing contained therein through a central discharge 32 having a similar charging opening 33 is provided but the foraminous belt 34 is divided into 'sections which are connected together by insulating 'transverse ribs 35. As shown more particularly in Figure 4, the annular carriage is comprised of a plurality of supporting brackets ,36 connected together by annular angle bars 31 and provided with rollers 38 operating upon an vannular track 39. A spider 40 carried by a shaft y 4| driven by the motor 42 with bevel gears 43 and riage. The lower insulated segments or sections of the foraminous supporting web constitute lower electrodes and a plurality of oscillators ;may be arranged about the periphery of the annular carriage except for the vicinity of the charging opening of the housing. Metallic belts 41 are connected to one pole of a corresponding oscillator and driven by small motors 48 serve to connect the foraminous supporting web adjacent .the respective portions of the periphery of the annulus to distinct oscillators.

The other pole of the several oscillators may be grounded. An

` upper foraminous web 49 is suspended from the roof of the housing 32 a su'icient distance above the carriage to allow ample room for passage of the parcel 50 and web 49 is grounded. The section of this upper foraminous electrode adjacent the charging opening 33 may be and is preferably omitted. An annular duct 5I is arranged below the carriage and has openings 52 in its upper surface to discharge upwardly. As in the first embodiment, a chamber 53 is provided adjacent the entrance to the duct and contains a heating coil 54 and a fan 55 or blower to force air into the duct. At one or more points about the annular duct, humidiers 56 are arranged therein. These humidifiers may be controlled to impart a predetermined relative humidity to the air that is circulated past the parcels to be dried. An internal cone 51 is formed within the hous` ing to provide a more or less fiaring annulus for `discharging the air and the evaporated moisture duct 58 which may again be provided with a suction fan or blower 59.

This embodiment of the invention has the advantage of providing for independent control of the various stages of drying. Thus, at the first stage of drying, the relative humidity of the heated air forced past the parcel being dried and the electrical characteristics of the oscillator may be preselected independently of those provided in successive stages of the drying path or cycle. Thus, the drying may be started while in the presence of high humidity heated air and at successive stages, the relative humidity may be progressively lower. At the same time. the electrical characteristics of the oscillators may be progressively changed to effect a higher heating rate in successive stages of the cycle until a predetermined moisture content of the parcels is obtained, after which the heating effect may be progressively decreased. If desired, instead of providing a single air inlet and `heating chamber for the entire duct, a plurality-of suchmay be arranged thereabout, a separate/heater and fan serving to supply the heated'air adjacent each distinct portion of the cycle. Thus, the temperature as well as the relative humidity and dielectric heating effect at any given stage can be controlled independently of those characteristics at succeeding stages ofthe drying cycle.

The present invention is adaptable to the drying of Aparcels of lamentary material# which merely contain moisture and also tosuclfi parcels as may have .been treated with other conditioning agents whether in the presence' of water as a solvent or in the presence of an organic solvent of volatile character. 'For example, the apparatus may be used to dry rayon to which a soap solution has been applied, with the vobject of leaving a small amount of soap upon the fibers as a conditioning agent. Again, an aqueous emulsion o1' a solution in an organic solvent of oils, soaps, fats, dyes, pigments or waxes may have been applied. Again, the conditioning medium may be one whichv undergoes condensation or curing to a nal insoluble condition, examples of such being urea formaldehyde, resins," melamine resins, or rubber and synthetic rubber dispersions.

The present invention lends itself readilyto procedures in which the removal of solvent and/or reaction between components of the conditioning medium or between one or more components of the conditioning medium and the textile material is effected in separate stages of a multiple-stage process. For example, for many purposes it may be desirable to effect merely a removal of solvent at a relatively low' temperature until a denite solvent content is obtained and then finish the removal of solvent and simultaneous reaction at a high temperature for a short time. This procedure, in which a neg'- ligible amount of reaction is effected during the preliminary stage and the reaction and nal drying are both accomplished in a short time in the nal stage is particularly advantageous when the conditioning medium contains one or more components which, during the treatment with heat, undergo a change to an insoluble condition such that removal of the balance of the solvent by diffusion through the insoluble product is greatly hindered or almost completely prevented.

While preferred embodiments have been described, it is to be understood that they are assegno merely illustrative of the invention, and that changes and Variations may be made herein without departing from the spirit and scope as defined by the appended. claims.

We claim:

1. Apparatus for drying parcels of iilamentary material and the like comprising a oraminous belt electrode for supporting a parcel to be dried, means for moving the electrode means through a path, a duct arranged below at least a portion of the path, fan means for forcing a gaseous medium through the duct, means adjacent the fan means for heating the medium, independently controlled humidifying means spaced at intervals in the duct, spaced openings along the duct for directing the medium upwardly toward the foraminous electrode means, co-operating electrode means arranged above the path, and means for impressing a high frequency electric current on the electrode means.

2. Apparatus for drying parcels of lamentary material and the like comprising a plurality of ioraminous electrodes for supporting the parcels to be dried, an annular carriage for supporting the electrodes, means for rotating the carriage to move the electrodes through a cy clical path, upper electrode means arranged above the ioraminous electrodes, parcel-charging and discharging positions along one portion of the path, supply means for producing a high frequency electric current, and means for electrically coupling the supply means with the oraminous electrodes as they pass through the portion ci the path between the charging and discharging positions.

3. Apparatus for drying parcels of nlamentary material and the like comprising a plurality of ioraminous electrodes for supporting the parcels to be dried, an annular carriage for supporting the electrodes, means for rotating the carriage to move the electrodes through a Cyclical path, upper electrode means arranged above the foraminous electrodes, parcel-charging and discharging positions along one portion of the path, a plurality of independently controlled supply means for producing a high frequency electric current, and means for independently coupling the several current supply means to the foraminous electrodes in succession as they pass through successive lportions of the path between the charging and discharging positions.

4. Apparatus for drying parcels of lamentary material and the like comprising a plurality of ioraminous electrodes for supporting the parcels to be dried, an annular carriage for supporting the electrodes, means for rotating the carriage to move the electrodes through a cyclical path, upper electrode means arranged above the foraminous electrodes, parcel-charging and discharging positions along one portion of the path, a plurality of independently controlled supply means for producing a high frequency electric current, means for independently coupling the several current supply means to the foraminous electrodes in succession as they pass through successive portions of the path between the charging and discharging positions, means for heating a gaseous medium and a duct for direct ing the heated medium upwardly through the electrodes.

5. Apparatus for drying parcels or lamentary material and the like comprising a plurality of iorarninous electrodes for supporting the parcels to be dried, an annular carriage for supporting the electrodes, means for rotating the carriage to move the electrodes through a cyclical path, upper electrode means arranged above the oraniinous electrodes, parcel-charging and discharging positions along one portion of the path, a plurality of independently controlled supply means for producing a high frequency electric current, means for independently coupling the several current supply means to the foraminous electrodes in succession as they pass through successive portions of the path between the charging and discharging positions, means for heating a gaseous medium and a duct for directing the heated medium upwardly through the electrodes as they pass between the charging and discharging positions, and independently controlled humidifying means spaced in the duct at intervals along the path.

FREDERICK W. KOSTER. LOUIS A. OBERLY.

FEBLENES CITED The following references are of record in the iile of this patent:

UNITED STATES PATENTS

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