US3143398A

US3143398A - Sealed apparatus for drying, warming and aerating materials

Info

Publication number: US3143398A
Application number: US223763A
Authority: US
Inventors: Rassele E Swarthout
Original assignee: Challenge Cook Bros Inc
Current assignee: Challenge Cook Bros Inc
Priority date: 1962-09-14
Filing date: 1962-09-14
Publication date: 1964-08-04
Anticipated expiration: 1981-08-04

Description

Aug. 4, 1964 R. E. swARTHou'r 3,143,398 SEALED APPARATUS FOR DRYING, WARMING AND AERATING MATERIALS INVENTOR. HSSELE En/A205 .5w/949711007' TroQNEz/s.

Aug. 4, 1964 R. E. swAR'rHoUT SEALED APPARATUS FOR DRYING, WARMNG AND AERATING MATERIALS 5 Sheets-Sheet 2 Filed Sept. 14, 1962 lll/J INVENTOR. Pssas EIM/meas imprima;

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ug- 4, 1964 R. E. swARTHou-r 3,143,398

SEALED APPARATUS FOR DRYING, WARMING AND AERATING MATERIALS Filed Sept. 14, 1962 3 Sheets-Sheet 3 FGc 3a I: '72 'a ,I I I I 70 I I I I I h l l I l I l l I I I I II 7g I I J a LMI" I L7/ .'gne VINI I lI n /140 I 'I I I I I I I- u *1T* *.l:

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United States Patent O 3,143,393 SEALED APPARATUS FOR DRYING, WARMING ANI) AERATENG MATERIALS Rasseie E. Swarthout, Downey, Caiif., assigner to Challenge-Cook Bros., Incorporated, Los Angeles, Calif., a

corporation of Caiiforna Filed Sept. 14, 1962, Ser. No. 223,763 3 Claims. (Cl. 34i 23) This invention relates to a device for drying, warming and aerating materials, particularly damp textile materials, although its adaptability for use as a dehydrator for removing liquids from any other materials or matter by aerating and drying will be readily apparent from the description hereinafter contained. The device is especially useful as a commercial laundry dryer.

Laundry dryers presently irl use are generally of the type in which damp clothes are tumbled about in a perforate basket or similar container, with warm air passing through the perforations in the basket or container. T he elfectiveness of such devices is limited by several factors. For instance, heavier clothes, or those having a greater moisture content, often do not receive sufcient exposure to the warm air passing through the perforations, and thus are subjected to a limited amount of drying, whereas, the lighter clothes, or those having a lesser moisture content, are frequently subjected to excess warm -air exposure beyond normal needs, so that consistency of drying is difcult, and often impossible, to maintain. Consequently, and particularly in commercial laundry operations, due to the varying moisture content of the articles of clothing removed from the dryer after the drying operation, subsequent operations, such as mangling or ironing operations, must be constantly adjusted to compensate for the dierences in moisture content of various articles in the same processed batch of clothing.

It is therefore an object of the present invention to provide a drying device which will gently process the treated material throughout the drying operation without subjecting it to the rigors of tumbling, and Will permit the full aeration of all of the materials in a batch, without regard to varying Weights and moisture content, so that all materals simultaneously processed will be delivered from the device in a consistently dry or damp condition, and further processing in a mangler or ironer may be accomplished without frequent adjustment of the mangler or ironer.

It is another object of the invention to provide a device for dehydrating materials by which the heat applied to the materials and the time of processing may be accurately regulated to lcontrol the amount of moisture removed from the processed materials.

It is still another object of the invention to provide a device of the character described which will permit gentle and eiective aeration of materials being processed therein for controlled periods of time.

It is a further object of the invention to provide such a device which is of relatively simple construction and which is easy to maintain and operate.

With these and other objects in View, the invention consists of the construction, arrangement and combination of the various parts of the device whereby the objects contemplated are attained, as hereinafter set forth, pointed out in the appended claims, and illustrated in the accompanying drawings.

In the drawings:

FIGURE 1 is a side elevational view, partly in section, of the device of the present invention.

FIGURE 2 is an enlarged View, partially broken away, taken on the line 2 2 of FIGURE 1.

FIGURE 3 is an enlarged View, partially broken away, taken on the line 3 3 of FIGURE l.

3,143,398 Patented Aug. 4, 1964 FIGURE 4 is an enlarged View, partially broken away, taken on the line 4 4 of FIGURE 1.

As illustrated in the drawings, a rectangular, closed, outer housing 10 is provided, said outer housing 1li having a top panel 11,

side walls

12 and 13, a front wall 14, and a rear wall 15.

Within said outer housing 1) is an inner housing, generally designated 16, the Walls of which are spaced apart from the walls of said outer housing 19 to form a passage for secondary ambient air. Said inner housing 16 is comprised of a front wall 16a, a rear wall 17, and side walls 1S and 19. Portions of said side walls 18 and 19 may be irregularly constructed to form battles, as illustrated in FIGURE 1 of the drawings.

A plenum chamber 20 is disposed within inner housing 16 adjacent top 11 of housing 1i), but spaced apart from top 11 and side wall 12 of housing 10 to form a passage for ambient air around plenum 20. Said plenum 20 has a top panel 21, an end Wall 22, side walls 23, and a perforate bottom 24. The other end 25 of plenum 26 is open and is aligned with an opening 25a in outer housing side wall 13. Inner housing side wall 19 terminates at bottom 24 of plenum 2i) so as to support plenum 2t). Plenum 29 may also be supported in spaced relationship to side wall 12 by any suitable means, such as by a bracket 26. lVall 1S of inner housing 16 terminates at a point aligned with the bottom of an opening in wall 12 of outer housing 10, at which point a right angle leg or bracket 18a is provided, said leg 18a being disposed in said opening in wall 12 of housing 1t) so as to form a support for wall 18.

A burner 30 is provided. Burner 30 is suitably mounted on and supported by a platform 32 which is cantilevered externally on side Wall 13 of housing 1t) below opening 25a. Platform 32 in turn may be supported by a support bracket 34 mounted on platform 32 and side wall 13. Platform 32 also has mounted thereon a combustion chamber 36, and an air duct 38 leads from heater 30 to combustion chamber 36. The top 37 of combustion chamber 36 is open.

Disposed above combustion chamber 36, and preferably spaced apart from open top 37 of chamber 36, is an air duct 40 which passes through opening 25a in wall 13 of housing 10 and gives access to plenum 2i) at open end 25 thereof, so that air heated in chamber 36 will iiow freely from chamber 26 into plenum 20, and thence through perforated bottom 24 of plenum 2i? into inner housing 16.

Chamber 36 and duct 40 duct 4t) being spaced from tinue the secondary ambient tioned.

Adjacent the bottom of inner housing 16 is a second plenum chamber 50, having a perforated top 52 to allow the passage of air from inner housing 16 into plenum 50. Plenum Sil has a bottom 54, side walls 55, and an end wall 56. Plenum 50 is supported in housing 10 by any suitable means, such as by a bracket 57 disposed in an opening in Wall 12 of housing 10. End 58 of plenum 50 is open. Wall 19 of inner housing 16 terminates above open end 58 of plenum 50, and may be supported on Wall 13 of outer housing 10 by any suitable means, such as a leg or bracket 19a.

Mounted on open end 58 of plenum 5t) is an air duct 60 which passes through an opening in housing 10 to an exhaust blower 62 driven by a motor 64. Blower 62 has an exhaust opening 66. Blower 62 is preferably spaced apart from housing 10.

A series of endless conveyor belts, spaced one from the other, are disposed substantially horizontally and parallel to each other within housing 10 between plenum 20 are enclosed in a housing 42, said housing 42 so as to conair passage hereinabove men- 'drive sprockets 91, which are and plenum 50. Ten of said conveyor belts are illustrated in FIGURE l of the drawings, but it will be understood that any number of said belts, greater or less than ten, may be provided. Said belts are designated 70, 80, 90, 100, 110, 120, 130, 140, 150, and 166. Said belts are preferably perforate, and are of any suitable flexible construction. By way of illustration, but not by way of limitation, said belts may be constructed of spaced wires, articularly jointed at their ends, such as belts known commercially as Cyclone Flex-Grid Belts, illustrated in FIGURES 3 and 4 of the drawings.

Said belts move alternately in opposite directions, the top of belt 70 moving to the left, as it is illustrated in FIGURE 1 of the drawings, the top of belt 80 moving to the right, etc., through the entire series of belts.

Belt 70, the uppermost of said belts, is spaced below the perforated bottom 24 of plenum 20. A platform 71 is cantilevered outwardly from side wall 12 of housing and mounted on platform 71, adjacent the outer end of said platform 71, are drive sprockets 72, mounted on a shaft 72a. Belt 70 is disposed around drive sprockets 72 and passes through the lower portion of the opening in wall 12 in which leg 18a is disposed, to and around idler sprockets 73, said sprockets 73 being spaced apart some distance from wall 19 of inner housing 16.

Idler sprockets 73 are mounted on shafts 74, as best illustrated in FIGURE 2 of the drawings, each of said shafts 74 being rotatably supported by a bearing 75, which is mounted on a bracket 76, said bracket 76 being mounted externally on

walls

16 and 17 and disposed between

walls

16 and 17 and

walls

14 and 15 of housing 10, with each shaft 74 passing through an appropriate opening in either

wall

16 or 17.

An air barrier 77 is disposed between the upper and i lower ights of belt 70 adjacent sprockets 72 and within the opening in wall 12, the purpose of said air barrier 77 being to prevent the free escape of air from the interior of housing 16.

Belt 80, the next belt below 70, is disposed around drive sprockets 81, which are mounted closely adjacent to wall 19. Each of the sprockets 81 is mounted on a shaft 82, rotatably supported by a bearing 83, in turn mounted on a bracket 84, mounted externally on walls y16 and 17 and disposed between

walls

16 and 17 and

walls

14 and 15, each said shaft 82 passing through an appropriate opening in either

wall

16 or 17 After passing around drive sprockets 81, belt 80 extends to and passes around idler sprockets 85, said idler` sprockets 85 being spaced apart some distance from wall 18. As illustrated in FIGURE 2 of the drawings, sprockets 85 and the shaft on which they are supported are mounted and supported similar to idler sprockets 73 Afor belt 70.

Belt 90, the next belt below belt 80, is disposed around mounted closely adjacent to wall 1S. Each of the sprockets 91 is shaft mounted and disposed and supported similarly to drive sprockets v81 for belt 80. After passing around drive sprockets 91,

belt 90 extends to and passes around idler sprockets :92, which are spaced apart some distance from wall 19. Each of said idler sprockets 92 is shaft mounted and disposed and supported similarly to idler sprockets 85 for belt 80.

Alternately, belts 100, 120 and 140 are disposed, mounted and driven similarly to belt 80; and belts 110, 130 and 150 are disposed, mounted and driven similarly to belt 90, the drive sprockets for belts 100, 120 and 140 being arranged in a substantially vertical plane with drive sprockets 81 for belt 80; the idler sprockets for belts 100, 120 and 140 substantially in a vertical plane with idler sprockets 85 for belt 80; the drive sprockets for belts 110, 130 and 150 in a substantially vertical plane with drive sprockets 91 for belt 90; and the idler sprockets for belts 110, 130 and 150 in a substantially vertical plane with idler sprockets 92 for belt 90.

Wall 18 of inner housing 16 is terminated closely adjacent to belt 150, and may be supported on the wall of housing 1t) by a bracket or right angle leg, such as leg 18]), illustrated in FIGURE l of the drawings.

Belt 160, the lowermost of the belts, is spaced above the perforated top 52 of plenum 50. Belt 160 is disposed around drive sprockets 161. Said sprockets 161 are mounted closely adjacent to the terminal end of wall 19, and are shaft mounted and supported similarly to the drive sprockets for belts S0, 100, and 140, and in a substantially vertical plane with said other drive sprockets. A platform 162 is cantilevered outwardly from side wall 12 of housing 10; and mounted on said platform 162, adajcent the outer end of said platform 162, are idler sprockets 163. Belt is disposed around drive sprockets 161 and passes through the lower portion of an opening in wall 12 of housing 10, to and around idler sprockets 163.

An air barrier 164 is disposed between the upper and lower flights of belt 160 adjacent sprockets 163 and within the opening in wall 12, the purpose of said air barrier 164 being to prevent the free escape of air from the interior of housing 16.

Louvers, such as louvers and 171, illustrated in FIGURE 1 of the drawings, are provided in the walls of housing 10, the purpose of said louvers being to permit the introduction of secondary ambient air into the air passage space between the outer and inner housings, 10 and 16, respectively.

Mounted externally on

walls

12 and 13 are

motors

180 and 190, respectively.

Motor propels a belt or chain drive 181 which is operatively mounted on the shaft of the drive sprocket for belt 150. A belt or chain drive 182 is operatively mounted on the same shaft of the drive sprocket for belt 150, and to the shaft of the drive sprocket for belt 130. Similarly, a belt or chain drive 183 is operatively mounted on the same shaft of the drive sprocket for belt 130 and the shaft of the drive sprocket for belt 110; a belt or chain drive 184 is operatively mounted on the same shaft of the drive sprocket for belt 110 and the shaft of the drive sprocket for belt 90; and a belt or chain drive 185 is operatively mounted on the same shaft of the drive sprocket for belt 90 and the shaft of the drive sprocket for belt 70, the latter belt or chain drive 185 passing through openings in the inner and outer housings of the device.

Motor propels a belt or chain drive 191, which passes through an appropriate opening in the walls of the outer and inner housings and is operatively mounted on the shaft of the drive sprocket for belt 160. A belt or chain drive 192 is operatively mounted on the same shaft of the drive sprocket for belt 160 and to the shaft of the drive sprocket for belt 140. Similarly, a belt or chain drive 193 is operatively mounted on the same shaft of the drive sprocket for belt 140 and the shaft of the drive sprocket for belt 120; a belt or chain drive 194 is operatively mounted on the same shaft of the drive sprocket for belt 120 and the shaft of the drive sprocket for belt 100; and a belt or chain drive 195 is operatively mounted on the same shaft of the drive sprocket for belt 100 and the shaft of the drive sprocket for belt 80.

It will thus be seen that when

motors

180 and 190 are actuated, the various belt or chain drive linkages from motor 189 will cause the top ights of

belts

150, 130, 110, 90 and 70, to move to the left, in the position of the device illustrated in FIGURE 1 of the drawings, and the various belt or chain drive linkages from motor 190 will cause the top ights of

belts

160, 140, 120, 100 and 80, to move to the right, so that each succeeding ight will move ina direction opposite to that of the flight immediately above it. Regulation of the speeds of motors 180 and 190.will control the predetermined time of passage of the material to be treated along each ight and through the entire operation. It will also be apparent that the time of passage of the material through any given por- 2:9 tion of the device may be controlled and regulated by merely varying the relative size of the sprockets, or, preferably, varying the number of teeth in various sprockets, so that, for instance, as is generally desired, the upper belts will move relatively slower and the lower belts will move relatively faster, permitting longer exposure of the material to heat in the upper portions of the device, and shorter exposure in the lower portions.

The openings in side wall 12, through which belt 70 and belt 160 extend, are necessarily relatively large, and extend a substantial distance above the top iights of said belts, in order to permit the free passage of the materials to be processed into and out of the device. It is preferred that means be provided to prevent the free escape of heated air in the device through said enlarged openings. To accomplish this result, an air seal or shield 200 is provided for the opening through which belt 70 passes; and an air seal or shield 300 is provided for the opening through which belt 160 passes.

Shield 200 comprises a housing 201, which is mounted on platform 71 and extends upwardly therefrom so as to surround the opening in side wall 12 at which the material to be processed is introduced into the device. Housing 201 has side walls 202, and a top section 203, said side walls 202 and top section 203 being mounted on wall 12. The end 204 of housing 201 is open.

Pivotally mounted at wall 12, adjacent the top of the opening in wall 12, is a transverse plate 205, the outer end 206 of which is arcuate to accommodate the roller hereinafter described.

A roller 210 is suitably rotatably mounted on transverse plate 205 below arcuate end 206 of transverse plate 205, and disposed so that upward movement of said roller 210 will cause .transverse plate 205 to pivot upwardly within housing 201. Roller 210 is of substantially the same width as belt 70.

Transverse plate 205, with roller 210 mounted thereon, may be spring-biased downwardly, or may be normally downwardly disposed by gravity, as desired.

A stop 220 is mounted within housing 201 to limit the upward movement of transverse plate 205 with roller 210 mounted thereon. Roller 210 may be an idler roller or, if desired, may be power driven. If roller 210 is power driven, in lieu of stop 220 an automatic shutoff safety control may be provided, the purpose of stop 210, or the automatic shutoff safety control, being to limit the height of the material to be introduced into the device for processing.

Shield 300 is similar in construction to shield 200. It comprises a housing 301, which is mounted on platform 162 and extends upwardly therefrom so as to surround the opening in side wall 12, at which the material which has been processed is discharged from the device. Housing 301 has side walls 302 and a top section 303, said side walls 302 and top section 303 being mounted on wall 12. The end 304 of housing 301 is open.

Pivotally mounted at wall 12, adjacent the top of the opening in wall 12, is a transverse plate 305, the outer end 306 of which is arcuate to accommodate the roller hereinafter described.

A roller 310 is suitably rotatably mounted on transverse plate 305 below arcuate end 306 of transverse plate 305, and disposed so that upward movement of said roller 310 will cause transverse plate 305 to pivot upwardly within housing 301. Roller 310 is of substantially the same width as belt 160.

Transverse plate 305, with roller 310 mounted thereon, like transverse plate 205, may be spring-biased downwardly, or may be downwardly disposed by gravity, as desired. Roller 310 may be an idler roller or, if desired, may be power driven.

In operation, burner 30 is ignited and warm air then flows from combustion chamber 36 through duct 40 into plenum chamber 20, from which it passes through the perforations in the bottom 24 of plenum chamber 20 into inner housing 16', and is drawn by the action of exhaust blower 62 down through the entire interior of the device, into lower plenum chamber 50, and then through duct 60 to exhaust blower 62, from which it is exhausted through opening 66.

FIGURE 1 of the drawings shows the heated air being introduced from the side of the device to the upper plenum chamber, and then progressing downwardly through the device and being exhausted through the lower plenum chamber. It will be understood that in lieu of introducing the heated air from either side, it may be introduced from the back, front, or top of the device, as desired, and furthermore, that by reversing the positions of the heating assembly and the exhaust assembly, the heated air path as illustrated may be reversed, with the heated air being introduced into the bottom plenum Vchamber and progressing upwardly until it is exhausted at the top of the device.

Furthermore, it will be understood that the amount of heat applied may be controlled, if desired, by any suitable means, such as by a heat meter (not illustrated) introduced, preferably, into the air exhaust assembly.

The continuous exhaustion of the heated air from the device will cause ambient air to enter through the louvers, such as

louvers

170 and 171, from which, by reason of the combustion action in combustion chamber 36, said ambient air is drawn through the space between the outer and inner housings into heater housing 42, Where it is mixed with warm air, heated and circulated through the device as hereinabove described. The passage of such ambient air between the outer and inner housings not only provide a ready air supply, but also serves to control the outside temperatures of the outer walls of the housing 10.

Meanwhile,

motors

180 and 190 are actuated to drive the various drive sprockets for

belts

70, 80, 90, 100, 110, 120, 130, 140, 150 and 160, as hereinabove described, causing said belts to move in the alternate directions hereinabove mentioned.

The material to be dried, warmed or aerated is placed on belt 70 over platform 71, externally of housing 10, and before roller 210. Belt 70, moving to the left, as illustrated in FIGURE l of the drawings, will carry said materials into housing 10. Roller 210 will ride over the material being processed as the material passes under roller 210. If the mass of the material being processed is too high to pass through the opening in wall 12 and be carried internally along the belt system of the device, the stopping of roller 210 by the stop or automatic safety control 220 will prevent the further passage of the material into the device until the excessively high material is removed or adjusted to proper height.

The material being processed will be carried continuously along belt 70 until belt 70 reaches and passes around its idler sprockets 73. The continuous movement of belt 70 around idler sprockets 73 will cause the material to op over and drop to the next belt directly below belt 70. The movement of belt 80 to the right n a direction opposite to belt 70, will carry the material through the device in the opposite direction until belt 80 reaches and passes around its idler sprockets 87, whereupon the material being carried by belt 80 will iiop over and drop to the next belt directly below belt 80. This process will continue until the material has opped over and dropped to the lowermost belt 160. The movement of the top ilight of belt to the right will complete the drying, warming or aerating process and will carry the material out of the housing, under roller 310 and along platform 162, where the processed material is removed.

The baled construction of walls 18 and 19 will aid in turning the materials being processed as the materials pass from one belt to the next lower belt, so that alternately, opposite sides of the material will be exposed to greater aeration. As shown in FIGURE l of the drawing an open external end; a transverse ings, the bafes are an integralV part of the Walls 18 and 19, are disposed at inwardly directed angles, and extend generally from `a point adjacent the top of one belt flight to a point adjacent the top of the next succeeding tlight below, so as to' turn the material and direct it to the next lower ight.

In lieu of forming said baffles as an integral part of walls 18 and 19, said batlles may be separately, pivotally mounted so as to be adjustable in pitch.

The drying and aeration of the materials being processed of course will be greatly facilitated by the fact that variousV belts are perforate and permit the free passage of the warm air therethrough.

Although the invention lhas been herein shown and described in what is conceived to be the most practical and preferred embodiment, it is recognized that departures may bemade therefrom within the scope of the invention, which 'is not to be limited to the details disclosed herein but is to be accorded the full scope of the claims so as to embrace any and all equivalent structures and devices.

What is claimed is:

1. A device for drying, warming and aerating materials which comprises: a substantially air-tight main housing having outer Walls, and having inner walls spaced from said outer walls; plenum chambers mounted adjacent the top and the bottom of said main housing; means for introducing warm air into one of said plenum chambers and passing said warm air from said plenum chamber into the interior of said main housing; means for passing said Warm air from the interior of said main housing into the other of said plenum chambers; means for exhausting warm air from the other of said plenum chambers; a plurality of power-driven, substantially horizontal conveyor belt flights vertically spaced from each other and disposed seriatim in said main housing in the stream of said Warm air intermediate said plenum chambers, each belt flight moving in a direction opposite to that of the belt ight immediately above it, the topmost and the lowermost of said belt flights extending beyond said main housing; a horizontal platform mounted externally of said main housing; an opening in said main housing aligned with said platform, the topmost of said belt nights extending over and being supported by said platform and passing through said opening, said opening accommodating said topmost belt ilight and materials loaded thereon; a secondary housing mounted on said platform and on the main housing, said secondary housing enclosing said opening and havplate disposed in said secondary housing and pivotally mounted on said main housing above the opening in said main housing; a roller suspendably mounted on said transverse plate and disposed so as to ride'on said topmost belt ight and to serve, in combination with said transverse plate, as an air seal for said main housing opening; means for dropping said materials from each belt ight to the next beltiight immediately below it at the end of each such belt flight; and means for removing said materials from the lowermost of said belt ilights externally of said housing.

2. A device for drying, warming and aerating materials, as defined in claim l, including stop means in said secondary housing for limiting the upward pivotal movement of said transverse plate and the roller mounted thereon. Y

3. A device for drying, Warming and aerating materials, as Ydeiined in claim 1, wherein the means for removing said materials from the lowermost of said belt ilights comprises: a horizontal platform mounted externally of said main housing; an opening in said main housing aligned With said platform, the lowermost of said belt ights extending over and being supported by said platform and passing through said opening, said opening accommodating said lowermost belt ight and materials loaded thereon; a secondary housing mounted on said platform and on the main housing, said secondary housing enclosing said opening and having an open Vexternal end; a transverse plate disposed in said secondary housing and pivotally mounted on said main housing above the opening in said main housing; a roller suspendably mounted on said transverse plate and disposed so as to ride on said lowermost belt flight and to serve, in combination with said transverse plate, as an air seal for saidmain housing opening.

References Cited in the le of this patent UNITEDSTATES PATENTS 453,562 Koyl lune 2, 1891 1,797,335 Fedeler Mar. 24, 1931 2,018,505 Suhr Oct. 22, 1935 l 2,043,265 Roeder June 9, 1936 2,758,388 Westerberg Aug. 14, 1956 2,995,829 Allen Aug. 15, 1961 FOREIGN PATENTS 4,182 Great' Britain 1892 7,010 Great Britain 1904

Claims

1. A DEVICE FOR DRYING, WARMING AND AERATING MATERIALS WHICH COMPRISES; A SUBSTANTIALLY AIR-TIGHT MAIN HOUSING HAVING OUTER WALLS, AND HAVING INNER WALLS SPACED FROM SAID OUTER WALLS; PLENUM CHAMBERS MOUNTED ADJACENT THE TOP AND THE BOTTOM OF SAID MAIN HOUSING; MEANS FOR INTRODUCING WARM AIR INTO ONE OF SIAD PLENUM CHAMBERS AND PASSING SAID WARM AIR FROM SAID PLENUM CHAMBER INTO THE INTERIOR OF SAID MAIN HOUSING; MEANS FOR PASSING SAID WARM AIR FROM THE INTERIOR OF SAID MAIN HOUSING INTO THE OTHER OF SAID PLENUM CHAMBERS; MEANS FOR EXHAUSTING WARM AIR FROM THE OTHER OF SAID PLENUM CHAMBERS; A PLURALITY OF POWER-DRIVEN, SUBSTANTIALLY HORIZONTAL CONVEYOR BELT FLIGHTS VERTICALLY SPACED FROM EACH OTHER AND DISPOSED SERIATIM IN SAID MAIN HOUSING IN THE STREAM OF SAID WARM AIR INTERMEDIATE SAID PLENUM CHAMBERS, EACH BELT FLIGHT MOVING IN A DIRECTION OPPOSITE TO THAT OF THE BELT FLIGHT IMMEDIATELY ABOVE IT, THE TOPMOST AND THE LOWERMOST OF SAID BELT FLIGHTS EXTENDING BEYOND SAID MAIN HOUSING; A HORIZONTAL PLATFORM MOUNTED EXTERNALLY OF SAID MAIN HOUSING; AN OPENING IN SAID MAIN HOUSING ALIGNED WITH SAID PLATFORM, THE TOPMOST OF SAID BELT FLIGHTS EXTENDING OVER AND BEING SUPPORTED BY SAID PLATFORM AND PASSING THROUGH SAID OPENING, SAID OPENING ACCOMODATING SAID TOPMOST BELT FLIGHT AND MATERIALS LOADED THEREON; A SECONDARY HOUSING MOUNTED ON SAID PLATFORM AND ON THE MAIN HOUSING, SAID SECONDARY HOUSING ENCLOSING SAID OPENING AND HAVING AN OPEN EXTERNAL END; A TRANSVERSE PLATE DISPOSED IN