US2821030A - Apparatus for drying materials in paste form - Google Patents

Description

S. BOGATY Jan. 28, 1958 Q APPARATUS FOR DRYING MATERIALS IN PASTE FORM Filed Oct. 21, 1953 2 Sheets-Sheet l v Jan. 28, 1958 s QGATY APPARATUS FOR DRYING MATERIALS IN PASTEFORM Filed Oct. 21,1953

f J? I 5 v 3 1a 2/ r J e o e a e 0e 0 o%%%%%%% United States Patent '0 APPARATUS FOR DRYING MATERIALS IN PASTE FORM Stanislaus Bogaty, Philadelphia, Pa., assignor to Proctor & Schwartz, Inc., Philadelphia, Pa., a corporation of Pennsylvania Application October 21,1953, Serial No. 387,490

4 Claims. (Cl. 34-225) .This invention relates-to new and nsefulimprovements in apparatus for dryingmaterials in the form or consistency of paste.

The principal object of the present invention is to provide a novel method for drying materials in paste form which is elficient, andboth economical and practical for commercial production requirements.

Another object of the invention isto provide a novel apparatus for carrying out the method.

These and other objects of the invention and the various features and details of the construction and operation thereof are hereinafter fullysetforth and described with reference to the accompanyingdrawings, in which:

Fig. l'is a plan view of'apparatus embodying the present invention for drying materials in paste form and consistency in accordance with the method of the present invention, a portion of thetop of the dryer having been cut-away to illustrate certain details ofthe construction;

:Fig. 2 is a side elevational view of the disclosure in Fig. 1;

Fig. 3 is an enlarged sectional view taken on line 3-3, Fig. 1; and

Fig. 4 is an enlarged sectional view taken 'on line 44, Fig. 3.

In accordance with the present invention the material to'be dried is deposited in the form of a relatively plastic or viscous mass or paste in a plurality of continuous ribbons 1 upon an endless conveyor 2 of heat-conducting material such as, for example, stainless steel of sufliciently' thin gauge to render it flexible and enable it to pass about the usual rolls or pulleys on which endless conveyors customarily are mounted. The ribbons 1 of the. material extend longitudinally of the conveyor upon and are disposed in spaced'parallel relation transversely thereof.

.The ribbons 1 of the'material are dried by passing them' through drying apparatus, generally designated 3, which is constructed and operable in accordance with the present invention. Referring to the drawings, the drying apparatus 3 of the present invention comprises a housing or enclosure 4 including top wall 5, opposite end walls- 6 and 6a and opposite side walls 7 and 8, respectively. The conveyor 2 with the ribbons 1 thereon enters the dryer 3 at the lefthand end thereof with respect to Fig. 1 of the drawings and emerges from the dryer at the righthand end thereof.

The interior of the dryer 3 is sub-divided by transverse vertical partitions 9 and 10 into three substantially identical sections A, B and C, respectively. Mounted in each ofthe sections A, B and C of the dryer 3 in overlying relation to the conveyor 2is a hood structure 11. As shown in Fig. 3 of the drawings, in each section the, hood 11 is in the general form of a truncated pyramid which is divergent downwardly from an inlet opening'12 for air at the top thereof to the lower end of the hood which extends longitudinally thefulllen'gth'o'f the-section and has a width transversely-of the dryer which is substantially'coextensive with the width of the underlying-conveyor 2. The hood 11 in each section is supportedfrom a horizontal partition 13.

overlying-the top of the hood 11 in each sectionof the dryer'and in communication with the air inlet opening 12 thereto is an air chamber 14 into which air isdischarged laterally through control dampers :15 fromafan or blower 16 driven by a suitable motor 17 mounted on the top 5 of the dryer housing. The partition member 13 alsosupports the air chamber 14 and fan or blower 1 6.

A vertical partition 18 is mounted below the horiz'ontal partition 13 and extends longitudinally centrally of each section of the dryer to "sub-divide the upper portion of the section below thehorizontal partition 13 into separate zones .for movement of the drying air in opposite directions.

An air inlet port 19 to each of the sections'Aand B of the dryer'isprovided in the side wall .8 of the dryer housing and the'amount of air admitted to the sections through the ports 19 is controlled by means of louvers or shutters 20. Mounted horizontally in each of sections A, B and C of the dryer and supported between the side wall 8thereof and vertical partition 18 is a heating elemen't'21for heating the drying air.

By reason of the construction and arrangement described, air discharged or admitted to the lower portions of the sections rises upwardly between the dryer wall 8 and partition 18, passes through the heaters 21 where the temperature of air is raised to the desired degree. The heated air then continues its upward passage through an opening 13a in the partition 13 to the intake of the fan or blower 16 from which it is discharged laterally and passes through the control louvers or shutters 15 to the air chamber 14. From the chamber 14 the heated air passes downwardly into and through the hood 11 and is discharged from the bottom of the hood through a series of transversely extending narrow elongated nozzles 22 arranged in spaced parallel relation longitudinally of the dryer section. The discharge nozzles 22 may be formed by stamping the same in the bottom plate 23 of the hood 11, for example, as shown in Fig. 4 of the drawings.

As shown, the nozzles 22 are disposed transversely of the conveyor 2 and the direction of travel of the ribbons 1 of the material thereon and the length of the nozzles. 22 is such that the nozzles extend coextensive with the width of the said conveyor and entirely overlie the ribbons 1 thereon. By virtue of this construction and arrangement, the heated drying air passing downwardly through the hood 11 is discharged through the nozzles 22 perpendicularly into impinging contact with the upper surface of the ribbons 1. The drying air then flows laterally in opposite directions across the ribbons on the conveyor and downwardly about the lateral edges of the conveyor 2 into the lower portion of the dryer section.

A predetermined portion of the spent drying air in sections A and B is reheated and recirculated in the manner previously described, and the balance is exhausted from the dryer. For this purpose there is provided in the lower portion of each section A and B of the dryer an exhaust duct '24 having inlet openings 25 in the top thereof for the air. The exhaust ducts 24 extend longitudinally beneath the conveyor 2 the entire length of each section A and B, respectively. The exhaust air is conducted from ducts 24 by ducts 26 to an exhaust manifold. 27 which extends longitudinally above the dryer housing and has its outlet end connected to the intake of an exhaust fan or blower 28.

In some cases, in order to prevent'the two outermostribbons 1 of material adjacent the opposite side edges of. the conveyor 2 from drying too rapidly and at a faster rate than-the -more inwardly disposed ribbons 1, it has been found-desirable-to partially reduceor throttle the air discharged from the nozzles 22 directly onto the surface of these outermost ribbons 1. In accordance with the present invention this may be accomplished'effectively by partially covering the discharge nozzles 22 adjacent the outermost ribbons-1 only of the conveyor 2', -by a perforate bafiie or like structure29. Such a baflie' may consist, for example, of one or more thicknesses of screening-andin practice satisfactory results have been obtained byemployingltwo thicknesses of 16 meshscreening arranged, for example, .as shownin Fig. .3 of the drawings. This construction and. arrangement servesto throttlet-the dischargedfromithe end portions of the nozzles 22 sufliciently to retardthe rate of .drying of.the.outermost ribbons lsothat they dry at substantially thers'ame rate asthe innermost ribbons. t i t i The heaters 21 inieach of the sections ofthedryer are controlled by conventional .temperature-responsive instruments to heat the ,dryingsair passing .therethrough and provide a suitable drying temperature for the particular material at the discharge nozzles 22.. The temperature required in any given case depends upon the speed of travelof theconveyor 2,; the consistency and thickness of the particular ribbons of the material being dried and thehumidity of the inlet'air, higher temperatures being employed in the summer season because of the relatively high humidity conditions existing in that season, and lower temperatures being employed in the other seasons and in periods of relatively low humidity. The construction and arrangement of the fan or blower 16 and the hoed 1 11 issuch as to discharge air; from the nozzles 22 at high velocity.

In addition to the temperature control provided in each of the sections A, B and C of the dryer, provision is also made for controlling the relative humidity in the-central section B. This may be accomplished, for example, by controlling the amount of air exhausted from section B, for example, by means of bafile or shutters 32 provided in the exhaust manifold 27 (see Fig. 2) or by means of a water spray (not shown) mounted within the section. Either such device may be controlled manually or automaticallyin conventional manner'by standard instruments and controls readily available commercially.

In practicing the invention, the material in paste form is deposited upon the conveyor 2 in ribbons l having a predetermined depth or thickness and these ribbons are thoroughly dried during passage through successive sections A, B and C of the dryer. Inthe processof drying, the thickness or depth of the ribbons is reduced. Immediately prior to emerging from the dryer, the steel conveyor may be cooled, for example, by passing it in contact with a chilled or refrigerated roll, for the purpose of removing any tackinessin the dried'ribbons and also to shrink the ribbons slightly to facilitate their separation and removal from the conveyor. The dried ribbons of the material are then doctored or otherwise separated from the conveyor 2 and wound upon suitable mandrels according to the conventional practices.

' I claim:

7 1. A dryer for materials in paste form comprising a housing, means subdividing said housing into a succession of drying sections, an endless conveyor passing entirely through the housing and the several drying sections thereof to convey thin layers of the material successively through said sections, a plurality of narrow elongated discharge nozzles for drying air in each section of the dryer overlying the conveyor and disposed in spaced parallel relation lengthwise of the conveyor with the individual nozzles extending transversely thereof, said nozzles being disposed to discharge drying air downwardly perpendicular to the plane of the conveyor, and perforate members disposed in the air stream at the opposite end portions of the discharge nozzles operable to partially throttle the drying air discharged through said nozzle end .portionsandthereby retard therateof dryingofthe outer portions of the material on ,the conveyor so that they dry at substantially the same rate as the inner portions thereof. t

2. A dryer for materials in paste form comprising a housing, means subdividingfsaidhousing into a succession-of drying sections, an endless conveyorpassing entirely throughthe' hous'i the several drying 'sections thereof to convey thin layers of the material successively through 'said sections; a *pmram of gna'rrow elongated 'discharge rrozzlesfordryingaiir ineach section of the dryer overlying the conveyor and 'extending'in spaced parallel relation lengthwise of the conveyorwith the individual nozzles extending transversely thereof, said nozzles being disposed to discharge the drying air downwardly perpendicular to the plane of the conveyor, means in each section to heat the drying air to a predetermined temperature, meansin each section -to force --the heated drying air through the dischargenozzles-at a' selectedvelocity, and baffle means in each section extending'longitudinally of the conveyor intermediate the opposite side portions of -the'convey'or 'and the overlying'end-portions of the discharg'enozzles top'arltially throttle the discharged drying air and thereby-retard the rate of drying of the outer; portions of;. the materialion the conveyor'sothat they dry at substantially thesame rate as the inner'-por-- tions thereof;

3. A dryer for materials' impas'telform comprising a housing, means subdividing saidhousing'into a succes-' sion of drying sections, ,anendless conveyor passing en-- tirely through the housing and the several drying sections thereof to convey thin layers ofthe material successively through said sections, a plurality of narrow elongated discharge nozzles for drying air in each section of the dryeroverlyingtheconveyor and extending in spaced parallelrelation lengthwise of the conveyor with the individual nozzles extending transversely thereof, said nozzles being disposed to discharge the drying air downwardlyper v pendicular to the plane ofithe conveyor, and baffle' means in each section extending longitudinally of the conveyorintermediate; the opposite side portions of the conveyor and the overlying end portions of the discharge nozzlesto partially throttle the discharged drying air and thereby retard the rate of drying of the outer portions of the ma-' through the housing and the several drying sections there-'- of to convey thin layers of the material successively through said sections, a plurality of narrow elongated discharge nozzles for drying air in each section of the'dryer; 'overlying the conveyor'a'nd extending in spaced parallel relation lengthwisev of the'conveyor with the individualnozzles extending transversely thereof, said nozzles being disposed to discharge the drying air downwardly perpendicular to the planeof the conveyor, means in each sec.-

tion to heat the drying air to a predetermined temperature, means in each section to force'the heated drying through the discharge nozzles at a selected velocity, baffle means in each section extending longitudinally of the conveyor intermediate the' opposite side portions of the conveyor and the overlying end portions of the discharge nozzles to partially throttle the discharged drying ail-land. thereby retard the rate of drying of the outer portions of.

thematerial on the conveyor so that they dry at substanf tially the same ra 13.5 theinner portions thereof, and an. exhaust air duct extending longitudinally beneath "the conveyor. in at least s'ome'pf said sections, and exhaust I meansconnectedjto each 'of said ducts in said sections.

- it B ferssssa ntq eu ne as ,1.

References Cited in the file of this patent UNITED STATES PATENTS Hopkins July 30, 1912 Fosbraey June 29, 1915 5 Field Nov. 9, 1920 Braemer July 28, 1925 6 Brabaek Nov. 7, 1933 Bogaty Jan. 4, 1944 Dorsch May 20, 1947 Shegda Apr. 1, 1952 Gillis Feb. 10, 1953 Brabaek Oct. 6, 1953

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