US1564565A - Method of drying and oxidizing materials in suspended condition - Google Patents

Description

Dec. 8, 1925- 1,564, 6

G. D. HARRIS METHOD OF DRYING AND OXIDIZING MATERIALS IN SUSPENDED CONDITION Original Fll'ed 1920 2 Sheets-Sheet l w um anvwntoz (50900 flaw/heme Dec. 8, 1925- G. D. HARRIS METHOD OF DRYING AND OXIDIZING MATERIALS IN SUSPENDED CONDITION o l.F'iled Oct. 23, 1920 2 sheets sheet 2 awvemcoz 60000 190 fywa e/a WQHS W Patented Dec. 8, 1925.

UNITED STATES PATENT OFFICE.

GORDON DON HARRIS, F ISLIP, NEW YORK, ASSIGNOR, BY MESNE ASSIGNMENTS, TO

THE INDUSTRIAL DRYER CORPORATION, OF STAMFORD, CONNECTICUT, A COR- PORATION or CONNECTICUT.

METHOD OF DRYING AND OXIDIZING MATERIALS IN SUSPENDED CONDITION. Original application filed October 23, 1920 Serial .No. 419,052. Divided and this application filed October To all whom it may concern Be it known that I, GORDON DON HARRIS,

a citizen of the United States, residing at Islip, county of Suffolk, State of New York, have invented a certain new and useful Method of Drying and Oxidizing Materials in Suspended Condition, of which the following is a specification.

This invention pertains to a method of drying and oxidizing, the same being useful in the evaporation of moisture from materials in a suspended condition while in transit within a substantially. closed chamber.

The invention of the application is a division (continuation) of a prior application filed by me on October 23, 1920, Serial No. 419,052, in so far as pertains to matter common to the two applications, wherein is discarrying into practice the method of my invention, although various other forms of apparatus may be resorted to for practicing the invention, such as the apparatus of my application filed February 27, 1922, Serial No. 539,668.

According to the invention, material in the condition of a web is transported in the form of loops or festoons within a substantially closed chamber, although it is to be distinctly understood that the inverttion is not restricted to the drying of festoons or loops of web material, for the reason that material in sheet or slab form adapted to be suspended from an appropriate carrier may be subjected to oxidizing or drying treatment in accordance with my invention.

The operation of drying material suspended from a carrier, particularly web material in the form of loops or festoons, should be conducted under conditions which involve a minimum disturbance of such material in transit within a substantially closed chamber, and to this end a drying or oxidizing atmosphere is circulated downwardly upon the suspended material and within the chamber, and said drying oroxidizing atmosphere is exhausted from the bottom -portion of said closed chan'ibcr so as to carry the moisture evaporated from the material away from the suspended material.

.It is desirable in this art to subject the closed one form of apparatus suitable for presence of such 30, 1922. Serial No. 597,712.

material undergoing treatment to a drying or oxidizing atmosphere characterized by the presence of a certain moisture, to the end that the atmosphere flowing into contact with the suspended material is suited to the character of such suspended material. To this end I utilize a certain. volume of the heated moist atmosphere flowing within the substantially closed chamber, and condition such atmosphere when exhausted from the chamber by mixing fresh atmospheric air therewith and reheating the mixed atmosphere so as to render the same available for recirculation within the substantially closed chamber and into contact with the suspended material therein, whereby the resulting atmosphere is conditioned during the recirculation thereof so that the moisture content and the heat units therein are apportioned to'the material under treatment.

In the drying of material in web form, such as paper or coated paper suspended in festoons or loops within the closed chamber, the atmosphere is conditioned by controlling the humidity and temperature thereof to the end that the heat units, required to evaporate or lift from the material a known quantity of moisture within a specified time, are supplied to such atmosphere in the period between the outflow from the chamber and the return of such atmosphere to the chamber, and concurrently with the step of reheating or boosting the atmosphere, the humidity or. moisture content thereof is modified by admixture of fresh air with the moist air exhausted from the chamber as a result of which the drying atmosphere is conditioned to accord with the condition of the material (paper) and the character of the coating thereon, the material and its coating being dried uniformly, thoroughly, and quickly.

By blowing air downwardly upon the suspended loops or festoons of a suspended web material, the air flows between the walls of said loops or festoons in a manner to disturb the suspended material to the least possible extent, thus. precluding the material from swaying while in transit within the chamber, and such downward flow of the air within said loops or festoonstends, furthermore, to spread the web material so as to preclude offsetting the coated surfaces A when coated material is undergoing treatment.

By exhausting air from the bottom of the chamber, moist air is removed from the presence of the suspended material, thus facilitating the drying of such material, and some of the moist air so exhausted from the chamber is utilized for recirculation within the closed chamber, the effect of which recirculation is to attain economy in the consumption of the energy (heat) required as one of the factors in the step of conditioning such atmosphere prior to the return thereof to the closed chamber.

The operation of blowing air downwardly upon the suspended material and within the chamber, and of exhausting air from the bottom of said chamber, secures a positive circulation of air within the festoons of the suspended material when looped web material is undergoing treatment, such positive circulation of the air insuring the flow for the full. depth of the festoons and for the full width of the web, thus securing the uniform and rapid drying of web material.

Accordingly my invention involves a mode of drying and conditioning material in web form, such as paper or coated paper, while suspended and being transported within a substantially closed chamber, whereby said paper is not only dried, but its physical condition is improved owing to the fact that the drying atmosphere is itself conditioned both as to its moisture content and as to its heat units, to the end that drying atmosphere is suited to the moisture content of the material, the latter being dried without concentrating the downwardly flowing atmosphere upon the middle portion only of the web of suspended material, thus obviating the formation of spots or streaks in the paper or the coated surface therepf.

In the drawings, there is shown a form of apparatus suitable for carrying my invention into practice, wherein Figure 1 is a side elevation partly in section, the plane of the section being indicated by the dotted line 11 of Figure 2.

Figure 2 is a view partly in plan and partly in horizontal section, the plane of the section being indicated by the irregular dotted line 2-2 of Figure 1.

Figure 3 is a vertical cross section in the plane of the dotted line 33 of Figure 1.

Figure 4 is a side elevation illustrating diagrammatically an apparatus of increased capacity as compared with the apparatus of Figs. 1, 2, and 3. and through which the suspended material is adapted to be carri ed cont1nuously.

In the form of apparatus shown. in the drawings for practicing my method, the suspended material is carried within a drying chamber A of any desired dimensions and capacity, the respective ends a, :b of said chamber being open so as to constitute an entrance vestibule, a, and an exit vestibule, b.

A trackway 0 extends lengthwisewithin said chamber, close to and parallel with" the top thereof, and on the rails of the trackway are adapted to travel rollers, c, of a movable carrier 0, the latter being shown as comprising roller chains provided with hangers, one of which is shown at C in Figure 3 as a stick, over which a web of material, shown at M in Figures 2 and 3, is looped for thepurpose of suspending fes toons of said web from the carrier.

The floor Z) of chamber A is provided with exits, d, for the drying atmosphere. Any desired number or arrangement of exits, d, may be employed for the flow out of the chamber A of that volume of the drying atmosphere which is to be mixed with fresh atmospheric air, and to be reheated, so as to condition the drying atmosphere in the process of recirculating the same back to the drying chamber A.

Beneath the floor of chamber A is a flue D, with which theexits, d, have free communication, and connected with this bottom flue D is the intake, 6, of an air circulating device, herein shown as a blower, E. Said blower is positioned exteriorly to the chamber A and flue D, preferably adjacent to the entrance vestibule a, see Figure 2.

On one side wall (wall of) of chamber A is provided a plurality of heating chambers F, whereas on the opposite side wall, a, of said chamber is constructed a plurality of fines, G.

Said heating chambers are separated one from the other by partitions f, so that the chambers afford distinct enclosures for the heating appliances, the latter being of an approved or suitable character, such as coils, F, for steam, water, gases, etc., said chamber F being shown as being positioned exteriorly to the drying chamber. The inner boundary wall, a of chamber F terminates, for a part of its length, below the top of chamber A, see Fig. 3, and thus the upper ends of said chambers F are left open to establish spaces of large area, which spaces perform the functiqn of ports f for the free flow of the drying atmosphere from said chambers F into the top portion of chamber A, see the arrows in Figures 1 and 3. The lower ends of said chambers F are open at f for free communication with a duct F to which is connected the outlet, 6, of blower E, the bottom' f of said duct F being inclined, see Figure 1, to result in a tapering duct F, by which the drying atmosphere is supplied uniformly to the several heating chambers.

In the apparatus shown, a desired number of flues G are provided on the side wall a of chamber A, interiorly thereof, for the rial.

to the heating effect of the hot drying atmosphere flowing within chamber A, whereby said flues G are heated for inducing the upflow therein of a certain volume of the moist atmosphere within chamber A. Each flue is open at the lower end, constituting an inlet 9, see Figure 3, whereas the upper end of sald flue is provided with a flange forming an outlet 9, open to the outside atmosphere, or, if desired, an exhauster, such as fan G, shown in dotted lines in Figure 3, may be used to mechanically exhaust some of the moist atmosphere from the chamber. The inlets to the flues G are above the floor of the chamber A, so that the air present within said chamber is free to enter the flues, the latter being temperature controlled for effecting the automatic discharge of a certain volume of the hot moist air from drying chamber A. In the operation of the apparatus shown,

a heating agent is 'suppiled. to the coils F, blower E is driven by a belt acting on the power pulley e of the fan shaft, and carrier C is set into motion for moving the suspended material within the drying. chamber When a web of material is suspended from the carrier, the festoons of said material sweep close to the floor of the drying chamber, andcertain of said festoons substantially close the entrance vestibule and the exit vestibule to said chamber A. The blower E exhausts air from the lower portion of the drying chamber andblows air downwardly upon the material suspended within the chamber. As stated, the air blown downwardly upon material suspended in loops or festoons acts to feed air into contact with the material without imparting a swaying movement thereto, and the air flowing downwardly within the festoons acts to spread the same so as to'preclude ofisetting of the coated surfaces thereof. The exhausting of air from the chamber removes moist air from the presence of the suspended material to facilitate the drying of said mate- The conjoint operations of blowing air downwardly-upon the material and within the chamber, and of exhausting air from the bottom of said chamber, establishes the'positive flow of air within and between thev loops or festoons of the suspended material, as a result of which the air is controlled, in a measure, to flow into the desired contact with the material, for the full depth of the suspended festoons and for the full Width of the web material.

The drying atmosphere is circulated by the action of the blower within the drying chamber, from the top downwardly to the bottom, and said atmosphere is exhausted mechanically out of the chamber at the bottom and returned to the chamber at the top thereof, the effect of which is to recirculate the drying atmosphere. In the progress of the air circulation, some of the moist air finds an exit from the chamber through the eduction flucs G in the form of apparatus admixture of fresh atmospheric air with the moist heated air, and by reheating or boosting the mixed moist air and fresh atmospheric air in the course of the recirculation. In the apparatus shown, the blower E exhausts some of the moisture laden heated air from chamber A through exits d and flue D, and said blower acts, also, to draw in fresh atmospheric air through the partially open vestibules a, b, at the respective ends of the drying chamber, which inflow of fresh air takes place through the spaces left around the looped ends of the suspended material and the Walls and the floor of said drying chamber. The fresh atmospheric -air is mixed with a volume of Warm moist air present in the chamber, and said mixed air is blown by the blower through chambers F, the latter acting to divide or channel the flow of the drying atmosphere so as to deliver the same uniformly to the drying chamber throughout the length thereof.- As the mixed air flows u wardly within the mannels or chambers it impinges-the boosters or reheaters F so as to restore to the drying atmosphere theheat units required for said atmosphere to exchange heat for moisture in the act of drying the material. The drying atmosphere recirculated by the blower is thus modified with respect to its moisture content and to its temperature, said atmosphere in the course of its-recirculation being modified as to its moisture content by the admixture of fresh atmospheric air therewith, and said atmosphere belng boosted and reheated by the coils F to the required temperature.

In the apparatus shown, the blower acts to circulate the drying atmosphere downwardly within the drying chamber and through exits d, flue D, thence to the blower itself, and thence through duct F channels or chambers F and ports f back to chamber itself. In my invention, a definite volume of the air present in the material chamber is recirculated. As will be understood, the air within the material chamber contains certain heat units and is in a more or less humid condition; if this air is discharged from the apparatus, the heat units and the moisture content thereof are lost; obviously this involvesa waste of the heat units and a loss of humidity. To effect economy, I recirculate a definite proportion of the drying atmosphere containing the heat units and 1 are independent of the recirculation means The volume of drying atmosphere so recirculated is conditioned prior to its return to the material chamber in two respects; first, the moisture content is reduced by the admixture therewith of fresh atmospheric air, and, second, the mixed air.

(composed of warm moist air and fresh air) is boosted to a desired temperature by interposing the boosters or radiators in the line of flow of such mixed airfor heating the same. Ftu'thermore, the recirculated atmosphere is divided into a plurality of streams, due to the fact that such recirculated mixed atmosphere is channeled by flowing within the chambers F, the latter containing the separate radiators or boosters F, whereby the individual streams of the recirculated atmosphere are heated to desired temperature or temperatures, and such conditioned individual streams are returned to the drying chamber at different points intermediate the ends thereof.

The apparatus of Figures 1, 2, and 3 is a single unit, but the capacity may be increased b the addition of a desired number of units as depicted in Figure 4.

Although I have shown and described the invention as adapted for the drying and conditioning of paper, it will be understood that other kinds of material, such as rubber slabs or hides, may be subjected to the treatment in accordance with my invention, provided such material is suspended from a carrier and moved within the chamber A, so as to be exposed to the downflow of a drying or oxidizing atmosphere. In this connection, it is proper to call attention to the fact that hides, the surfaces of which are coated with a dressing of a suitable character, may be treated to good advantage by carrying the same within the chamber and exposing said hides and the dressing to the action of an atmosphere.

Having thus fully described the invention, what I claim as new and desire to secure by Letters Patent is:

1. In the art of drying and conditioning paper in web form, the process which consists in continuously moving a web suspended in festoons within a chamber, blowing air downwardly upon the suspended festoons of said web. excluding side currents, and exhausting moist air from said suspended festoons at the bottom thereof, whereby moisture laden air is carried out of the chamber and away from the presence of the web. 7

2. In the art of, drying and conditioning paper in web form, the process which consists in moving a web suspended in festoons within a substantially closed chamber, and blowing downwardly upon said web a drying atmospherethe moisture content of which is modified by the previous admixture of fresh air with moist air drawn from the chamber and the temperature of which modified air is determined by reheating the same prior to the flow of such air into contact with said web in the meantime excluding side currents.

3. In the art of drying and conditioning paper in web form, the process which consists in moving a web suspended in festoons within a substantially closed chamber, and blowing a drying atmosphere downwardly upon the web and between the festoons thereof, in the meantime excluding side currents, mixing fresh air with a moist drying atmosphere and recirculating the atmosphere mixed with air to eii'ect the return of said atmosphere to said chamber, and heating the modified drying atmosphere during the flow thereof exteriorly to the substantially closed chamber.

4:. In the art of drying and conditioning paper in web form, the process which consists in moving a web suspended in festoons within a substantially closed chamber, circulating a drying atmosphere by exhausting the same in a humid condition from said chamber and by blowing said atmosphere downwardly upon the web and within the chamber, mixing fresh air with such drying atmosphere to modify the latter as to its moisture content, in the meantime excluding side currents and reheating the drying atmosphere during its flow exteriorly to the chamber.

5. In the art of drying and conditioning paper in web form, the process which consists in moving a web suspended in festoons within a substantially closed chamber, circulating a drying atmosphere by exhausting the same in a humid condition from said chamber and returning said drying atmos phere to said chamber at points distributed along the length of the chamber by blowing said atmosphere downwardly upon the web, in the meantime excluding side currents and reheating the drying atmosphere during the period of its circulation exteriorly to said chamber.

6. In the art of drying materials, the process which consists in moving suspended material within a substantially closed chamber, blowing air downwardly upon the suspended material and within the chamber, in the meantime excluding side currents and exhausting air from the chamber below the material suspended therein, whereby moisture is carried away "from the presence of the suspended material by the circulating air.

7. In the art of drying materials, the process which consists in moving suspended material within a substantially closed chamber, circulating a drying atmosphere by exhausting such atmosphere in a humid condition from the chamber at the bottom thereof and by blowing such atmosphere downwardly upon the suspended material and within said chamber, mixing fresh atmospheric air with the drying atmosphere to modify the latter as to its moisture content, in the meantime excluding side currents and heatin the dryin atmosphere during its flow exterlorly to sai chamber.

8. In the art of drying materials, the process which consists in moving suspended material within a substantially closed chamber, circulating a drying atmosphere by exhausting some of the moist air from said chamber and blowing such atmosphere downwardly upon the suspended material and within said chamber, in the meantime excluding side currents and discharging into the outer air some of the moist air from said chamber through outlets independent of the outlet path afforded by the exhausting operation.

9. In the art of drying materials, the process which consists in moving suspended material within a substantially closed chamber, circulating a drying atmosphere by exhausting some of the moist air from said chamber, and by blowing such atmosphere downwardly" upon the suspended material and within said chamber, 1n the meantime excluding side currents dischar ing into the outer air-some of the moist a1r from said chamber through outlets independent of the outlet afforded by the exhausting operation, and conditioning the atmosphere during its circulation exterlorly of the chamber by mix-- ing fresh air with such atmosphere and by heating such atmosphere to a desired temperature,

10. In the art of drying and oxidizing materials, the process which consists in moving suspended material within a substantially closed chamber, recirculating a def inite volume of a drying atmosphere by exhausting said atmosphere in a relatively humid condition from the presence of the material in said chamber, dividing the recirculated atmosphere into a plurality of streams channeling the flow of said atmosphere exteriorly to the substantially closed chamber, separately conditioning the respective streams of the recirculated atmosphere by the admixture of fresh atmospheric air therewith and by reheating the same, and returning said atmosphere to the chamber.

11. In the art of drying and oxidizing materials, the process which consists in moving suspended material within a substantially closed chamber, recirculating a definite volume of a drying atmosphere by exhausting said atmosphere in a relatively humid condition from the presence of the material in said chamber, dividing the recirculated atmosphere into a plurality of streams channeling the flow of said atmosphere exteriorly to the substantially closed chamber, separately conditioning the respective streams of the recirculated atmosphere by the admixture of fresh atmospheric air therewith and by reheating the same, and returning said atmosphere to the chamber by blowing the same downward upon the suspended material.

In testimony whereof, I have hereunto signed this specification at the State of New York, this 26th day of September, 1922.

eoRnoN n. HARRIS.

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