US2841381A - Tobacco curer - Google Patents

Description

y 1958 B. E. JONES 2,841,381

TOBACCO CURER Filed y 1953 5 Sheets-Sheet 1 Invenior Basil E. Jbnes .Aiiorney B. E. JONES TOBACCO CURER July 1, 1958 5 Sheets-Sheet 2 Filed May 14, 1953 Inveni-or- Basil E. Jbnes y M M Attorney B. E. JONES TOBACCO CURER July 1, 1958 Filed May 14, 1953 5 Sheets-Sheet 3 lnvenior I Basil E. Jones A ii'orney B. E. JONES TOBACCO CURER July 1, 1958 Y Filed May 14, 1953 5 Sheets-Sheet 4 July 1, 1958 B. E. JONES 2,841,

TOBACCO CUREIR Filed May 14, 1953 5 Sheets-Sheet 5 nven for asil .dbnes 960 W v i E ,A fiorn ey United States Patent dice 2,841,381 Patented July 1, 1958 2,841,381 TOBACCO CURER Basil E. J ones, Flossmoor, 111.

Applicat on May 14, 1953, Serial No. 354,935

5 Claims. (Cl. 263-19) The present invention relates to tobacco curing apparatus, and more particularly to an improved apparatus for curing yellow leaf tobacco in an expeditious and positively controlled manner.

In the disclosed embodiment of the tobacco curer, there is provided a heater located outside of the curing barn and enclosed in a casing from which a distributing duct leads to the interior of the barn to convey air and combustion products impelled by a blower in the casing. A pair of return ducts convey the barn air back from the barn to the casing to be circulated again by the blower, and exteriorly of the barn have openings through which outside air may be drawn into the casing by the blower to replace barn air. Dampers to close the openings are provided in the return ducts, so arranged that when the openings are closed the ducts are fully open and unobstructed so that all the barn air is recirculated and none isreplaced. The dampers maybe moved to block the ducts against passage of barn air while permitting unobstructed movement of outside air through the openings into the casing, or to partially block barn air passage and permit restricted outside air flow through the return ducts. The dampers thus control the proportion of barn air replaced by outside air. I

It is an object of the invention to provide apparatus vfor curing yellow leaf tobacco which affords improved control of all stages of the cure, and produces better results than previous apparatus.

It is another object to provide improved tobacco curing apparatus which employs positive air recirculating means to achieve uniform conditioning of the tobacco and reduction of the time required for curing.

Another object is the provision of improved tobacco curing apparatus incorporating means for accurate control of temperature and humidity conditions to obtain improved cure results.

Another object is the provision of improved tobacco curing apparatus operable at relatively low temperatures to obtain the desired curing temperatures.

It is also an object of the invention to provide improved tobacco curing apparatus incorporating means for controlling replacement of air in the curing barn by outside air in desired proportion.

Another object of the invention is the provision of improved tobacco curing apparatus including means for positively drawing outside air at a controlled rate into the curing barn.

A further object is. the provision of improved tobacco curing apparatus including heating means located exteriorly of the curing barn for elimination of fire hazard and accessibility.

Another object is the provision of improved tobacco curing apparatus discharging the products of combustion of the heating means into the curing barn to obtain re- Still another object is the provision of improved tobacco curing apparatus which employs a single heating means,

is compact and simple, is economical to operate and maintain, and achieves better and faster curing, than presently used apparatus.

It is a further object of the invention to provide tobacco curing apparatus requiring only intermittent operation of the heating means to obtain necessary temperatures, the frequency and duration of heating means operation being least when greatest humidity is required and greatest when greatest drying effect is desired.

Other and further objects, advantages, and features of the invention will be apparent to those skilled in the art from the following description and the accompanying drawings, in which: a

Fig. 1 is a vertical sectional view through a tobacco curing barn showing in elevation one embodiment of the apparatus of this invention;

Fig. 2 is a horizontal sectional view through the barn showing the apparatus in plan;

Fig. 3 is an enlarged fragmentary horizontal sectional view through the apparatus;

Fig. 4 is an enlarged vertical sectional view taken substantially as indicated by the line 4-4 of Fig. 3;

Fig. 5 is a vertical sectional view taken substantially as indicated by the line 5-5 of Fig. 4; and

Fig. 6 is a detail sectional view illustrating the arrangement for cooling the bearings of the blower shaft.

Apparatus now generally employed for curing yellow leaf tobacco, the type grown in the southeastern United States and requiring the application of heat under varying conditions of humidity for its cure, almost universally comprises no more than a plurality of pot or wick type burners disposed in the curing barn and. employing lines or stacks to carry off the products of combustion. High operating temperatures of about 500 F. and often rising to 600 F. are required to obtain the necessary curing temperatures, because of the loss of heat through the fines and also. because convection is depended upon for circulation of the air in the barn. The burners lack positive heat control and operate continuously, causing undesirable dissipation of moisture in the yellowing stage of the cure and consuming large quantitia of fuel. The high burner temperatures burn out the flues so rapidly that they must be replaced every year, or at most two years, and cause frequent fires the loss from which can be only partially covered by insurance and at high rates because of the frequent incidence. The absence of positive air circulating means not only increases the heat requirements but also tends to lack of uniformity in conditioning of the tobacco and to sweating of the tobacco due to air stagnation. Drying of the tobacco in. the later stages of curing is relatively slow due to the relatively haphazard and sluggish gravity circulation of the air. Openings in the walls of the barn having movable covers are provided for admission of outside air when desired, the outside air entering the barn only by convectional effect as the heated barn air escapes. Such prior apparatus is admittedly unsatisfactory being wasteful, ineflicient, and hazardous, as wellas. requiring a relatively long time to effect curing of the tobacco, but heretofore no apparatus efiectively solving the problem and remedying the defects hasbeen provided.

The apparatus of. the present invention overcomes the difliculties of prior apparatus and provides novel means for the curing of tobacco. In operation, the heater is on only intermittently, and particularly during the earlier portion of the cure for only a minor portion of the time. The blower is operated continuously so that a continuous recirculation of the barn air, including the products of combustion of the heater, is effected, and when desired a closely controlled proportion of. this air is. replaced by outside air, by manipulation. of the dampers. Temperatures and humidity conditions in the barn are readily maintained close to optimum during all stages of the cure so that the best possible results in curing the tobaccoare obtained. The recirculation of the air and the discharge of the combustion products intothe barn permit relatively low operating temperatures of the heater, as well as reducing thefiring'periods required. I Together with the .disposition'of the. heater'outside the barn, this practically eliminates the fireghazard inherent in. the

tobacco curing heaters now "generally used. Fuel consumption'is reduced to only about a third of that of present heaters, maintenance costs are brought to a minimum with the eliminationofthe ,flues employed with the .present heaters, and the lowering of insurance premiums and-fire losses. Only one heater instead of several is Enecessary, reducing initial. outlay. The positive recir culation of the barn air permit s more uniform conditioning of all the tobacco. and reduces the time required to bring the tobacco .to thedesiredcondition in each of the curing stages except the first or yellowing stage, in

whichit contributes to the desired maximum humidity.

Together-with the controlled intake of outside air and the moisture-dissipating efiect of the heater when burning, the recirculation provides very precise control of humidity in the barn. permits a reduction of the numbergof barns used. Thus the novel tobacco curing apparatus presents many advantages over that now generally used. 7

Referring to the drawings, there is' shown a tobacco curing ham or enclosure B having vent means of ordinary construction in the roof and a door in one wall, with tobacco Tracked in the barn in the usual way. 7 Outside of the barn and adjacent one of the Walls is a heater The shorter curing time required casing 10in the lower' part of which a heating fiame may be provided by an injection type oil burner 11 supplied'with fuel in any desired manner. A burner using fuel other than oil may of course be employed if desired. In the sides'and top of the casing there are a formed relatively small apertures 12 for a purpose explained hereinafter. In the upper part of the casing 10 is mounted a blower 13 drivenlby an electric motor 14 through belt and pulley means. The blower is preferably operable at more than one speed, so that the rate of air circulation effected thereby may be varied.. A

,distributing or outlet duct 15 extends from the casing adjacent the discharge or pressure side of the blower and through the barn wall into the interior of the barn, and

has a plurality of branch ducts16 extending therefrom to distribute substantially uniformly about the barn area 7 air and other gases impelled from the casing by the blower 13. The discharge-ends of the branch ducts 16 are bent upwardly, and spreader plates 17 are supported slightly above the open'ends'by angle'clips or the like to spread the air laterally as it issues from the branch ducts;

' -A pair ofreturn ducts 18 opening thro'ughjthe barn wall leadfrom th'e'interior of the barn to the lower part of the casing 10, on opposite :sides thereof, each duct communicating with the interior of the casing through 'a screened aperture 19 in the casing wall. An intake opening 20 is formed in each return duct exteriorly of the barn wall through which outside air may be drawn into the duc't and thus into the casing by the action of the blower 13. the opening 20'to swing within thednct 18 between a position closing the opening and a position blocking the duct between its inlet and the opening 20,'asbest shown in Fig. 3. When the opening is fully closed by the damper 21,-no outside air is drawn therethrough and the duct entirely unobstructed for return flow of air from the barn to the casing and blower, while when the opening is entirely unobstructed by the damper noair is allowed A damper 21 is hinged at one side of ends'tothe front and rear walls of the casing, thefupper edge of the liner 27 being slotted to accommodatethe' to flow from the barn to the casing through the duct and only outside air isdrawn into the casing by the'blower,

' so that all the air in the barn may be replacedby outside 1 Such replacement may be continuous, requiring only continued. operationof the blower. Replacement of, only and casing, so that the damper. 21 may be arrangedto swing horizontally between its extreme positions. The arrangement may be varied, however, and the desired result still achieved. The hinged dampers 21 are ordinarily swung to corresponding positions in their respec-' tive ducts, but they may be placed in non-corresponding positions. if desired, as indicated'in Figs. 2 to 4. The

'dampers 21 are moved manually by means of handles 21a projectinglthrough arcuate slots or other suitable openings in the top walls of the ducts 18, by'means o which the damper positions may be ascertained.

To control temperature in the barn B, suitable thermostatic means 22,such as a thermal bulb, is suitably mounted in the barn at an appropriate location audioperatively connected to control means 23 mounted outside the barn by which the setting of the means 22' may be adjusted, and through which the burner is turned'on and 01f as hereinafter explained. The burner 11 has'a the pot or combustion'chamber 25 within the casing 10, in which the actualcombustion of fuel occurs, The combustion chamber may" be of any appropriate construction, in this case being shown'a'sf a cylindrical pot of sheet metal lined 'with refractory material. A fuel inlet tube 26 extends from the injectionrnechanism'of the burner throughtlie chamber wall to directthe burning fuel into the chamber. Anysuitable igniting means '(not shown) may be employed to start burning of the fuel 7 whenever the burner'is operated. Within the casing'10 is a cylindrical sheet metalliner 27 'extendingzfrom adjacent the'topof the casing to, below the level of' the top of the combustion chamber, and spaced from both the casing and chamber; The liner has an external 'circumferential bead'2 8engagin'g the inner edge of aTcircularly apertured bottom plate 29 eXtendin'g"between 'the casing walls, and the liner., The outer edge of the'plate 29 is formed with a flange which engages'in a strip 30 of 2 section secured to the inner surface of the "casing. The liner 27 is thus supported inthe casing by the bottom plate 29 and the bottom. of the jacket space between the casing and liner is closed by the plate- 'Theuliner has a stepped portion at its upper partcut away 'as' in V dicated at 31 in Figs. 4 and 5,--to accommodate a housing j 32 for the blower13. V The-housing has a width corresponding tothe' length of the blower 'so that the blower may be received -be-' tween the side walls of'the housing, which are provided with intake apertures 33 providing communication-"be: tween the interionof the casing and the'blower' so that air and the products of combustion of 'the' burner 11 may be sucked into the housing by the blower and blown out :of the housing.and casing into the outlet duct 15 through an outlet 34 of the housing. The housingis supported in the casing'by apairof angle membersSS secured to the housing side wallsand fastened at their flanges of the angle members. A shield'36 is .secured to the lower portion 'of the blower housing in spaced relation to protect it from direct heat. .A cover plate.

37 closing'the major portion of the top of the liner is supported on the angle members. .Thelinerz27, bottom plate 29, and cover plate 37' define, a cooling ja'cket with the casing 10 through'whichoutside air may ciris readily' accorn- 'plished by locating the-damper intermediate its two ex-.

fit, closely about the housing 32, the wider part, of the cut-away portion 31 particularly leaving appreciable openings between the jacket space defined between the liner and casing and between the liner and blower housing. This loose fit is advantageous in facilitating assembly of the housing and blower in the casing and in preventing any possibility of starving the blower. Any air drawn from the jacket by the blower is restricted in volume because of the small size of the apertures 12, and its withdrawal from the jacket enhances the circulation of coolingair therein. "Peep-holes 3S and 39 in the top of the casing and in the cover plate 37, respectively, are provided in proper alignment for viewing the combustion chamber 25 whenever it may be desired to determine the condition of the fire.

The blower 13 is mounted on a shaft 40, the ends of which project through apertures 41 (Fig. 6) in the casing side walls and are journaled in suitable bearings 42 supported adjacent the side walls by angle brackets 43 or the like mounted on the walls. The cooling jacket is most effective in preventing heating of the casing 10, the casing remaining cool even when, the temperature at the combustion chamber and in the liner 27 is at its greatest, and the bearings 42 are similarly protected from heat radiated from the combustion chamber and liner. By means of the apertures 41, the bearings are further protected from internal heat developedby the rotation of the shaft and from heat conducted by the shaft from the interior of the casing. As the blower rotates with its shaft 40, it sucks air into the casing through these apertures to create air currents. which flow past the bearings and cool them, as will 'be evident particularly from Fig. 6. Thus whenever the blower is operating it is effective to counteract the heating of the bearings due to its operation. The importance of such an arrangement is evident when it is considered that the blower operates continuously throughout the conditioning period of the tobacco. The shaft 40 at one end carries the pulley through which the blower is rotated by'the motor 14.

The motor 14 and the motor of the burner 11, as well as the burner ignition means if of the electrical type, are operated by electricity from a suitable source, not shown, to which connection may be made by a cable 45 or the like having a terminal plug or other suitable means for making the connection, and leading to a main switch 46 with which a suitable fuse may be associated. The switch 46 serves also as the control switch for the motor 14, connecting the motor directly to the cable 45' when moved to circuit-closing position and shutting 05 current to the motor when in circuit-opening position, the motor being connected to the switch 46 by conductors 47. A burner control switch 48 connected to the burner 11 by wires 49 is arranged to place the electrically"operated elements of the burner in circuit with the cable 45 through the main switch 46, so that the burner cannot operate unless the switch 461s closed and the blower operative, even if the switch 48 is closed. A protective relay 5% also controlled by the switch 48 through conductors 51 is connected by wires 52 to the thermostatic control means 23. The relay 5i) operates to turn the burner 11 on or off in accordance with the heat requirements in the barn as reflected by the thermostatic means, and also to shut off the burner if a flame is not established upon starting of the burner or if the flame is extinguished during operation of the burner otherwise than in response to the thermostatic means. A limit control 53 is also provided and arranged in circuit with the burner 11 to open the burner circuit and stop burner operation in the event the temperature within the heater casing rises above a predetermined maximum. Alternatively, the control 53 may be arranged to open the circuit through the mainswitch 46, so that the blower 13 as well as the burner 11 .will be rendered inoperative in the event of excessive temperature within the casing. The several wires and conductors are preferably protected by conduit or the like, in accordance with usual practice. The relay 50 and limit control 53 are of known construction and need not be described in detail.

The apparatus when assembled and installed is operable upon connection to a suitable electrical line, so that upon closing the main switch 46 the motor 14- is started to operate the blower 13. The burner control switch 48 is closed, and if the temperature in the barn is below that called for by the thermostatic means, the control means 23 initiates operation of the burner 11. The dampers 21 are in position closing the intake openings 20 during the first stage of the curing operation, so that all the air in the barn is continuously recirculated throughout the barn uniformly about the tobacco and back through the casing 10 past the combustion chamber 25 and through the outlet duct 15 and its branch ducts 16 into the barn, impelled by the blower. All the products of combustion of the burner are entrained in the recirculating air and aid in heating it rapidly, there being little if any smoke. In the initial oryellow'ing stage of the curing process, high relative humidity, with relatively low temperature, is nccessar'y'to bring about setting of the desired bright yellow color in the tobacco before any appreciable drying occurs. Maximum humidity is obtained by the present apparatus because the air is retained in the barn after moving past the tobacco and extracting some of the moisture therefrom so that it is quickly brought close to its saturation point. Because of the recirculation, maintenance of the temperature in' the desired range is achieved by operation of the burner for only short periods at infrequent intervals, so that no appreciable burning off or dissipation of moisture by the burner flame occurs to lower the humidity. After the yellow color has set, the tobacco is dried and the stems killed, outside air in varying proportions being drawn into the barn by adjustment of the dampers 21 as already explained to reduce the relative humidity, and the temperature within the barn being gradually raised to a maximum by adjustment of the thermostatic control means 23, the. blower 13 continuing in operation throughout the. process and hastening the drying. The burner operates for a greater proportion of the time, thus aiding in reduction of humidity. After killing of the tobacco stems, which requires a relatively high temperature'and the lowest attainable relative humidity, the tobacco is in a very dry condition and therefore so brittle that it cannot be handled without breaking. It is rendered pliable by allowing absorption of moisture from the outside air, which at this stage is more humid than the atmosphere in the barn, and this ordering of the tobacco is accomplished much more rapidly by the present apparatus than by the commonly employed prior means, because the outside air is positively circulated past the tobacco rather than being merely allowed to enter the barn. To accomplish this, the burner is shut off and the dampers 21 are positioned to block return of air from the barn through the ducts 18 and to permit a maximum of. outside air to enter through the intake openings 20. Continued operation of the blower draws the outside air through the casing and impels it through the ducts 15 and 16 into the barn to flow in a continuous current past the tobacco, all of the air in the barn being continuously replaced by fresh outside air to bring a constant supply of moisture absorbable by the tobacco. The replaced air also carries otf much of the heat of the tobacco, so that both the tobacco and the interior of the barn are cooled sufficiently to allow the barn to be entered and the tobacco removed immediately after it is rendered pliable. The

prior, means available ,for :ordering, besides requiring a n e me d ot effect :anr pp eq a e loweringiof the temperature, so-,that considerable. additional time ,was required to allow for dissipationof the retained heat of the tobacco before it could be comfortably handled. V Whi1e thejinvention has been disclosed as embodied in the illustrated apparatus, it is to be understood that .the disclosejdapparatus representing only one possible embodimennoftheinvention is illustrative in nature.

;Whatisclaimedis:- V

1. Apparatus, for curing yellow leaf tobacco racked in "a'curing'barn, comprising a heater casing adjacent,

theexterior of-the barn, intermittently operable heating meanshaving a combustion chamber in said casing, an inner. liner providing a cooling jacket at the upper portion of the casing extending 'below the level of the top of the combustion chamber, a plurality of apertures in the casing forjcirculationof cooling air through'the jacket, a blower above the combustion chamber, a housing for the blower having an'inlet'c'ommunicating with the space'about the combustion chamber and an outlet, anjoutlet duct connecting the housing outlet with the interior oftheibarn, branchducts extending from the outlet duct having discharge openings spaced about the barn area, spreader means at said discharge openings .todistribute air impelled therethrough from the blower, ,a'pairof'return ducts leading fromthe interior of the barn to opposite sides of the casing for return flow of air through the casing to the blower, an intake opening in each return duct providing communication with, the outside ,atmosphere; to admit outside air to the casing, a damper; in each return duct adjustably movable between a positionclosing said intake openingand leaving ,Said duct;unobstructed and a position closing the duct against-communication between the barn and casing and providing unobstructed communication between said opening and casing to control the ratio of barn air and outside air drawn into the casing, thermostatic means in the barn adjustable fromthe exterior of thebarn for controlling the operation of the heating means'in accordance withtemperature requirements" in the barn, means. for preventing operation of the heating means when the blower is inoperative, and means for operating theblower for positive recirculation of air andthe heating means products: of combustion through the barn and casing, whereby'temperature and humidity conditions in,the barn are controlled by only intermittent op 'erationfof the heating means and replacement of barn 7 [air byoutside air in desired proportion.

2; Apparatus for heating an enclosure comprising a .casingadjacent the exterior of the enclosure, a combus- Qtion chamber in one endportio n of the casing having an open end for discharge of products of combustion,

a fuel burner producing products of combustion in the combustion chamberga generally cup-shaped sheet metal .liner having a closed end wall in the other end portion of the casing and having 'side wall structure overlapping the discharge end of the combustion chamber and spaced therefrom for receiving products of combustion from the combustion chamber and forming with the inner surface 7 5. The combination casing is upright,[the"combustion chamber is cylindrical of the casinga cooling jacket, an inlet duct connected 7 to the interior of the enclosure and opening intoithe cas; ing for conveying airfrom the enclosure through the casing and into the liner through the space between the side wall structure of the liner and the'combustion chamber for adiniziturewith, said productsof combustion lin a stream in; said liner, said duct having a valve-controlled opening to the atmosphere for admitting selected propoiftions of atmospheric air intosai d stream, a blower" having an inlet in. the "liner and adjacent the, closed end ivall'thereof for pulling said stream of mixed airand products of combustion fromsaid liner, and discharge duct means for conveyifigsaid stream from the'fblower through the sideIwall structure of the liner a'nclfthe Ycas- 7 .ing to the interior, ofthe enclosure; said casinghaving openings therein opposite theside 'wall sthlcture'of the liner and opposite'the' closedend wall of the liner 'for admitting atmospheric air to said cooling jacket,'a 'nd the intake side of said blower. being open to the jacket whereby'the fan pullsatmospheric air into the cooling jacket to cool the liner'jand'prevent' overheating damage thereto and discharges said air from the cooling jacket into said stream. 7

3. The combination claimed in claim 2, in which the casing is upright, 'with'the combustion chamber inits lower portion and the liner above the combustion chamber with the'closed' end wall of the liner in the toppertion of the casing, said inlet duct being connected to the 30 lower zone of the enclosure to be heated and to the lower portion of theicasin'g. a

AJThe combination claimed in claim 2,.including a pair of inlet ducts'connected to spaced apart portions of the enclosure to be heated and having their discharge ends connected to the casing on directly opposite sides thereof equidistantly apart on opposite sides of the combination chamber. 1 V i v claimed in' claim 2, in which the and positioned in the lower portion of the casing and the liner is positioned above the combusn'on chamber with the closed end'wall of the liner-in the top portion of the casing, and said combination including a pair of inlet ducts connected to spaced apart portions of the lower zone of the enclosure to be heatedand' having their discharge ends connected to the lower portion of the casing on directly opposite sides thereof "and on diametrically opposite sides of the combustion chamber.

7 References Cited in the file of this patent Niehus Nov. 11, 1952

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