US2943850A - Gas fired tobacco curers - Google Patents

Description

July 5, 1960 J. w. MOSELEY GAS FIRED romcco CURERS 2 Sheets-Sheet 1 7 Filed March 26, 1956 'jCheck Valve Initial High Pressure Req- Gos Tunk Valve 2 6i 567 et J. WOOTEN MOSELEY INVENTOR Air lnl 59 Pilot Je'r Line 47 Mom Jer Llne FIG. 2.

ATTORNEYS United States Patent 2,943,850 H GAS FIRED TOBACCO CURERS John Wooten Moseley, 610 N. (Iollege St., Kinston, N.C.

' Filed Mar. 26, 195-6, Ser. N0. 573,808

' 6 Claims. Cl. 263-19 1 The present invention relates to tobacco curing arrangements, and is primarily concerned with an improved gas burner, and-with curing systems employing such burners, whereby tobacco may be cured more efliciently than has been the case in the past.

As is well known, it is normally the practice to cure tobacco leaves in curing barns, and such barns ordinarily include a plurality ofheat sources disposed adjacent the floor thereof for effecting the desired cure. In the case of Bright Leaf tobaccos, for instance, the curing process normally comprises three successive phases, which phases are often termed the yellowing period, the drying period, and the period for killing the stern. In providing the differing temperatures characteristic of these different curing phases, various forms of heat sources have been employed heretofore'in known curing barns, and these heat sources have taken the form of coalstoker arrangements, oil burner arrangements, and more cure, the tobacco is subjected to a heat of between 100 and 155 F., for a period of approximately 48 hours and the barn temperature is periodically raised, within the specified range, during this 48-hour period to drive the moisture from the tobacco leaf. The time required to complete this drying period is ordinarily variable, and i i varies upwards with the humidity of the outside air. Subsequent to completion of the period required for drying the leaf, the temperature within the barn is further raised to a range of 165 to 180 F. for a period of 18 to 30 hours, thereby to drive moisture from the stem or to kill the stem. 7

The foregoing temperatures and time periods are char-' acteristic of substantially all curing systems utilized heretofore, whether coal, oil, or low pressure gas burners are used, and it will be appreciated that under such known 1':

systems of tobacco curing, a period of four and a-half to five days is usually required to complete each curing process. The relatively long curing time thus required heretofore has a definite and appreciable effect upon tobacco harvesting and curing operations as they are presently practiced. In this respect it should be noted that the harvesting of tobacco, at the present time, normally comprises several independent harvesting runs over the same tobacco field, and during each of these separated runs ripe leaves are picked from the tobacco plants being harvested. Inasmuch as the ripening of leaves may occur sooner than the four and a half to five day period required heretofore for curing a given run of tobacco, it has often been necessary in the past to store or otherwise delay the curing of a given run of leaves until thecuring barn completes the cure of a previous run. The long period of time necessary heretofore for curing a run of leaves is therefore highly undesirable and quite costly.

The present invention, through the use of an improved gas burnerarrangement adapted to operate with high pressure gas, completely obviates these disadvantages. In this respect, high pressure gas is defined as a gas pres sure in excess of one p.s.i., in distinction to the low pres sure gases described heretofore wherein pressures of approximately one-third p.s.i. have been employed.

It is accordingly an object of the presentinvention'to provide an improved tobacco curing arrangement. I

Another object of the present invention resides in the provision of a curing barn for tobacco which includes heat sources more elficient in their operation than those utilized heretofore.

Another object of the present invention resides in the provision of gas fired tobacco curers which use less total fuel for a given curing operation than has been the case heretofore.

Still another object of the present invention resides in the provision of a gas burner arrangement for'use in tobacco curing barns which reduces substantially the total time required for completing the cure of'a given run of tobacco leaves.

A still further object of the present invention resides in the provision ofa tobacco curer arrangement which is adapted to cure a greater quantity of tobacco over a given period of time than has been possible with prior curing systems. i i l A still further object of the present invention resides in the provision of improved gas fired burners for use in tobacco curing barns, which burners include a pilot flame system, whereby safer operation of curing barns may be effected.

Still another object of the present invention resides in the provision of a tobacco curing arrangement which is less expensive and more eflicient to operate than has been the case in the past.

In providing for the foregoing objects and advantages, the present invention contemplates the provision of a curing barn having a pluralityof gas burners disposed at spaced locations adjacent the floor of said barn. The several burners so disposed each include a main gas orifice and a pilot gas orifice, and gas lines are distributed throughout the barn, preferably below the floor or the ground comprising the floor of the barn, to interconnect respectively the main gas and pilot gas orifices 'of the several burners. As will become apparent from the subsequent description, the several burners are designed to operate efficiently with high pressure gas supplies;'and in practice, gas from an external source, such as a tank, is supplied via pressure regulating means to the gas lines within the barn at a pressure in excess of one p.s.i.-and preferably in the region of five p.s.i. It has been found in actual practice that by using high pressure gas systems, with the resultant hotter flames achieved thereby, a forcedcirculation of hot air is effected within the barn whereby the drying period for tobacco curing is cut by 25 to 35% of the time required heretofore when oil, coal stoker or low pressure gas burners were utilized. Similarly, the

, a tobacco barn in approximately seven days with the' high pressure system of the present invention, as com-.

time period for killing the stem is cut by one-third of the usual time, as compared to the time required for curing with prior art systems; and in actual practice it has been determined that two complete curings can be run through pared to the four and a half to five days required heretofore for a single cure.

In addition to the decreased time required for curing,

' companying drawings, in which: V,

a. .u1n; v oB c w the es ant ev c nton: eration, ithas been found that use of my invention results 'in less totalfuel being required to complete each cure thamhas been: th c s I t re ente y a s fican in s ac ev n the ket; fiec a e 'eh. u -i; ;;1.h forego ng; obje s, v ag s; c st uc ion and operation offthe present invention will; b'ecome jmore readily apparent from the followingdescription and jac- ;J' Fi gl1re 1 is a-schematic representation of a tobaced curing barn and gas fired-bu rnerarrangement constructed. in accordance with'the present invention; e i

E .Figure '1A illustrates an improved. safety valve such as may be employed in thepractice of the present inven:

- fRefem'ngnow. to Figure 1, itwill be seen that, in 'accordancewith thepresentinvemion, a tobacco curing be described. V a r V The elements 23 and 24 are conventional in nature ,n pte ablxtq a Pre su e of pprq ima l five p- This final reduced pressure gas, which is still at a high pres: sure as the term is understood in the art, then flows via a safety control 25 to a IT-junction 26, and is then coupled to the main and pilot orifices of the burners, aswill Q and many possible alternative constructions will be s ugdispositionsofgas burners alternative to that shownin Figure 1.

barn- 10. may: have a plurality of high pressure gas burn- V ers11lthrough'16 inclusive distributed adjacent the floor,

thereof. The several gas burnerseach have a maingas orifice and a pilot gas orifice, suchas will be described with greater particularity in conjunction with FigureZ;

btirnerslllithrough 16 are respectively interconnected, preferably by closed loop configurations of gas lines disposed Within the barn.

3i Thus; referring to Figure 1, it will be seen that burners 11 and 13;are disposed at 'opposirigends of a gas line 17; while burners 14 and 16 are preferably disposed at opposing ends of a gas line 18. Burners .12 and 15 are disposed adjacent the mid-points of lines 17 and 18 and the opposing ends of the lines 17 and 18 are in "turn connected by cross gas lines 19. Gas pressure for the main orifices of the several burners 11 through 16 in elusive is supplied at a point 20 in line 18; and this particular. closed loop or frame disposition of gas lines 17, 18'and 19 is chosen to avoid gas lines having dead ends which might effect back pressures, thereby to assure that substantially equal pressures appear at each of the sev 'ral burners 11 through'16. Afurther closed loop con figuration of gas lines, illustrated primarily in dotted line in Figure l and designated as 21, interconnects the sev eral pilot orifices 'of the gas burners 11 through 16 and these pilot orifices are again i a F preferably supplied with gas at a relatively high pressure. a

' 1h practice, the gas supply comprises a tank 22 disposed external of the barn and containing gas at a rela fiv'ely high pressure, the said tanked gas being ordinarily liquefied. The. gas from tank 22 is coupled to the barn I0 via an initial high pressure regulator 33 which'ordiw riarily acts'to reduce the gas pressure to approirimatelyls psi, and the gas at this initially reduced pressure is thereafter coupled to a further pressure reducer 24, preferably' located within barn 10 by elongated gas line In practice, line 28 enters therbarn adjacent the fourida-v tion thereof, extends upwards adjacent the barn Wall near its point of entry, and then extends for a substantial length thereof (see Figure 1) along the barn wall until it is dropped to the location of further pressure reducer 24. The elongated run of gas line 28 thus provided perpreheating of the gas in said line, whereby the efneieney of the several burners to be described is proved. r

Pressure reducer 24servesto further reduee the gas presmre to a pmsure still iii excess crime piss, and

' and the *mairl gas orifices and pilot gas orifices of the p gested' tothose skilled the art, :Ihe? safety control 25,

howevenjnust be designed. to operatesafely and surely at high pressures, and I' therefore prefer'to use a con struction of jthe type illustratedin Figure 1A. f Before i proceeding with a detailed de'scriptionof the particular.. 'safety control valve shown in'Fig'ure' l'A andcorres pond ing to element 25, however, it should be appreciated that the function of this valve is to disconnect the gasitank 22 from the several gas linesfeeding' the main and pilot rifi e .Q he. burner in, he neat m tt e; e sel-2 new teil c ga r 116 591 or. n the event t the Pr i ep e ter hine v lue l Safety control valves of the ypenormally employed at e Past o di ar sompris bimet li me ts s ekdwfihawdrie ement; aadfl r it s umber e hil etal siel men is flsu lt r n f le b a mel bums? fla d b t e sa pp y,; her hr a lweb he a supp y ti u s e h b rne th ebyt .efie x n are. propn'ate flexing of the bimetallic element andsa' closure of the safety control valve,' Such bimetallic control valves are subject to the disadvantage that thecontrolling flame may be blown out accidentally, thereby causing." closure of the gas lines at an improper time; and, these known controlvalves are subject to the further disadvan tage that they tend to break downyat the high gas pres:

sures employed in the presentsystems. It is therefore preferable, practicing my invention,- to use amechan-f ical safety control valve which is responsive to gas fail ure thereby to close'the gas lines, and the improved valve 7 7 now to be described is so designed that it must be manually reset before gas may passlonce more. to the main 7 and pilotorifices of my improved burners. Referring now to Figure 1A, it willbe seen that the improved manual safety control valve 25 may comprise a casting 90 adaptedto receive gas lines 91 and 92 where by gas may'selectively pass via the said gas Iinesand via the said casting 90 in the direction indicated. The casting- 90' includes a movable diaphragm 93 adapted, to seletitively close the flow path between gas lines. 91 and 92 and it ,will be appreciatedthat the particular representation of diaphragm 93, as illustrated in Figure 1A, 'is diagrammatic only. In practice, the casting 9-3 may'in c1 ude a tortuous, flow path between gas line 91 and gas line 92, and thiszflow' path may include-a valve seat, in which event the element '93 may'take the form of a small, valve elemfent'which can be selectively seated in the/said, y a

seat to isolate gas line 91 from gas linel92. @Cas'ting 99.

includes ;a.ffirs t slidablef rod 94 positioned above diaphragm .93 and. in'contact therewith; and the said rod 94 is biased in a downward direction. byaspring i95: The casting 90-further includes a second, rod 96*disposed; transverseto the rod 94, and biased .(fortheparticular I representation of Figure 1A)to the right by aspiring 91 e 95, whereby rod, 94is maintained in its upward posir In operation, and;when a normal, supply of gasfis coupled to linev 91, the pressure of gas fiowingfrom line 91 via casting 'and thence to line 92, holds diaphragm 93in an upward direction 'against'the restraint of spring t ionthereby assuring that rod 96 is maintained in its leftward positi on against the restraint of spring 97. If the gas supply sho uld failfor some reason, the reduced pressigre onthe lower surface of diaphragm 93 causes spring 1 94 x 9r s .4 1 1a. wn ard ct o t ereb my: i 18 d a h a m. 9 i e P sit on t glass e fi ra h area 99 2. .ei 4.-f -..;Wl 9l s heres m r ment; of rod 94 occurs, spring 97 urges rod 96. to the 'ielqm att em r e u e e setza sheuiarair'sasvg above-the uppermost end of rod 94 thereby to assure that diaphragm 93 is positively maintained in its downward or closed position. Even if the gas supply should thereafter be reapplied to line 91, diaphragm 93 will be 'mhibited from moving upward due to the positive lock-out function of rod 96 in its righthand position. 'No gas is.

therefore permitted to flow via casting 90 to the line 92 until rod 96 is manually pulled to the left, for instance by applying appropriate tension to extending end 98 thereof, in which event the said rod 96 will be moved out of contact with the upper end of rod 94 and the said diaphragm 93 and rod 94 can thereafter move upward into substantially the position shown in Figure 1A to maintain rod 96 in its lefthand position. By this arrangement, therefore, the safety control valve 25 permits gas to flow to the several main and pilot orifices of the gas burners so long as a normal supply of gas is provided; but if that supply should fail or the pressure thereof should fall below a predetermined minimum, the gas tank 22 will be effectively and positively isolated from the burners by safety control valve 25, and such isolation will be continued until the safety control valve 25 is manually reset.

It should be noted that the particular valve shown in Figure 1A is capable of operating at the high pressures utilized in my system, and will function properly to isolate the gas tank 22 from the burners even if, for some reason, the pressure reducers 23 and/or 24 should not operate properly whereby full tank pressure is impressed upon the safety control valve in its closed position. This particular consideration, which is not a characteristic of safety control valves known heretofore, is of considerable value in assuring safe operation of the over-all system..

The high pressure gas coupled to the aforementioned junction 26 is coupled via a manual cut-off valve 27, to the pilot gas lines 21, indicated by dotted line in Figure l. The said high pressure gas is also coupled via T-junction 26 to a high pressure thermostat or thermostatic valve 29, which permits or prevents the flow of high pressure gas to the gas lines supplying the main orifices of the several high pressure burners 11 through 16 in dependence upon the temperature within barn 10.

It will be appreciated that, in operation, the high pressure thermostatic valve 29 tends to open when the temperature within the barn falls below that desired, as determined by the setting of the thermostat 29; or in the alternative, the said thermostatic valve 29 prevents the flow of gas to the high pressure burners when the temperature within the barn is at or above a desired level. In actual operation, the thermostatic valve 29 may assume a number of positions between completely open and completely closed, and when the said valve is at some position intermediate its completely open or completely closed position, the pressure of gas passing therethroughtends to be throttled, with a resultant loss in gas pressure. In order to assure efiicient operation of the several bumers 11 through 16, therefore, a check valve 3% is prefere ably disposed in the gas line between high pressure thermostatic valve 29 and the feeding junction 29. This check valve 30 is pressure responsive in nature whereby no gas passes via thermostatic valve 29 to the orifices of the high pressure burners until a predetermined minimum pressure of gas is imposed upon the check valve 30, i.e.-

until the thermostatic valve 29 is substantially completely and fully opened.

It will be appreciated therefore that the over-all arrangement is such that the extremely high pressure of gas appearing in tank 22 is reduced to a desired high' pressure, preferably in the order of five psi. and preheated; and this reduced high pressure preheated gas is then coupled via a first network of gas lines to the pilot orifices of the several gas burners and is also coupled, via a thermostatic valve, and preferably via a check valve, to

a second network ofgas lines feeding the main orifices t ofthe gas burners; It willvfurther be'appreciated that the feeder. networks, due'to their preferably closed loop configurations, supply the aforementioned high pressure gas to both the pilot orifices and mainorifices offlthc several burnersat substantially the-same pressure, thereby further assuring the eflicient operation ofthe-overall system. 2;;

As is illustrated in Figure 1, the several high pressure, gas burners 11 through .16 are each enclosedina metal jacket or heat spreader such as 32 through 31, which heat spreaders or jackets are'adapted to provide a more uniform distribution of heat within the barn and which further serve to prevent possible falling, of leaves beingcured, into the burnersthemselves. The particular heat spreader or jacket employed will be described more fully; in connection with Figure 3. a a t In addition, it will be noted from Figure 1 that the over-all curing arrangement preferably includes a plurality of air inlets'or ducts, such as 38 through 43'inclu-- sive; and these ducts, which are more clearly illustrated. in Figure 2, communicate outside air to theinteriorof:

- the barn. Such air inlets are of course necessary due to the greater quantities of air or oxygen consumedduring the combustion of fuel within the barn; and in the past, curing barns have normally allowed for such air supply through the provision of apertures in the barn walls or) foundation. In accordance with one particular improve ment of the present invention, the air ducts 38 through 43 are supplied in place of such apertures provided here: tofore, and these ducts are individually associated with the several high pressure burners 11 through 16 and include a terminus adjacent each of said burners and within the metal jacket or heat spreader associated with that burner. By this arrangement therefore air which is admitted to the barn is supplied directly adjacent the burner whereby more efiicient mixing of air and gas is achievedthan has been the case heretofore; and in addition the the several gas burners, is also preheated as was the case with the gas supply, thereby even further improving the efliciency of the curing operation. The several gas burners 11 through 16 may assume a number of configurations provided they are designed to operate efliciently with the high pressure gas employed. One preferred construction in accordance with the present invention is illustrated in Figure 2, and it will be seen that a high pressure burner such as may be employed in the curing arrangement of the present invention, preferably comprises a main burner 44 which is of hollow, substantially tubular configuration. The tubular member 44 is open at its upper end 45 and is supported at its lower end on a base 46, through which base the supply, of gas at high pressure may be communicated via a line 47, preferably disposed beneath the ground comprising the floor of the barn. It will be noted that gas line 47 is coupled to an elbow 48 extending into the tubular burner member 44; and a main jet orifice 49 is slid ably placed into the elbow 48 adjacent the base 46 of the high pressure burner. This particular arrangement permits the tubular member 44, comprising the burner, to be lifted from the gas line whereby ready access to the gas orifice 49 may be had for cleaning purposes or the like.-

Tubular burner member 44 includes a plurality of air inlets or holes in the side walls thereof adjacent the gasorifice 49, and these holes, which are designated for instance as 50 and 51, are spaced uniformly about the circumference of tubular member 44 in staggered relation to one another. This staggered disposition of air inlets 50 and 51 causes air passing into the interior of tubular burner member 44 to assume a swirling or whirlwind pattern, thereby greatly enhancing the mixing ofair with gas emanating from orifice 49, and assuring that a hotter flame is produced by the burner than has been the case in burners utilized in curing barns heretofore.

In a preferred embodiment, thetubular member 44,

99 may be disposed between lines 17 and 18 adjacent the burners 12 and 15; and the said line 99 is disposed substantially parallel to each of gas lines 19. When such an arrangement is employed, three further burners 100 may be placed adjacent the mid-points of lines 19 and 99, as illustrated in Figure 4C, thereby to efiect a desired spaced disposition of nine gas burners. When the closed loop gas line configuration is employed, the gas inlet may be disposed adjacent a point 101, for instance, and it will be appreciated that the particular location of point 101, due to the closed loop configuration of lines utilized, may be at any convenient point in the closed loop gas line configuration without appreciably afiecting the equal pressures present at each of the several burners.

Still other arrangements of gas burners will be suggested to those skilled in the art, and it must therefore be understood that the foregoing description is meant to be illustrative only. All such modifications, in respect to the form of components which are employed and in respect to the disposition of those components, which are in accord with the essence of my invention, namely the use of gas fired burners operating at high pressure as the term is understood in the art, are accordingly meant to fall within the scope of the appended claims.

Having thus described my invention, I claim:

1. A tobacco curer comprising a curing barn, a plurality of high pressure gas burners spaced from one another adjacent the floor of said barn, each of said burners comprising a substantially upright tubular member open at its upper end and having a main gas orifice therewithin adjacent its lower end, each of said tubular members having a plurality of staggered air holes in the walls thereof adjacent said main gas orifice, a pilot gas orifice in each of said burners adjacent the open upper end of said tubular member, a source of gas under pressure disposed external of said barn, a first gas line extending from said source into said barn, pressure regulator means in said first gas line for reducing the pressure of gas from said source to a pressure in excess of one p.s.i., second gas lines coupling the reduced pressure gas in said first line to the main gas orifices of said burners, third gas lines coupling the reduced pressure gas in said first line to the pilot gas orifices of said burners, and thermostatic valve means in said second gas lines whereby flow of gas to said main gas orifices is dependent upon the temperature Within said barn.

2. The combination of claim 1 including pressure responsive check valve means in said second gas lines between said thermostatic valve means and said main gas orifices for preventing the flow of gas via said thermostatic valve means until said thermostatic valve means is substantially fully opened. 1-

3. The combination of claim 2 including air lines eX- tending from the exterior to the interior of said barn for supplying air to said barn, said air lines having termini adjacent the said air holes in each of said burners.

4. The combination of claim 3 including a plurality of metal enclosures covering the main and pilot orifices and the air line terminus of each of said burners respectively.

5. The combination of claim 1 including a plurality of heat deflecting metal jackets respectively disposed over said plurality of burners, each of said jackets comprising a roofed substantially cylindrical structure enclosing the main orifice and pilot orifice of its associated burner.

6. A tobacco curer comprising a curing barn having a plurality of gas burners spaced from one another on the interior of said barn, each of said gas burners comprising an elongated hollow tubular burner member disposed substantially upright adjacent the floor of said barn, said tubular burner member having a plurality of apertures adjacent the lower end thereof for the admission of air to said burner member, said apertures being disposed in the walls of said member and being spaced from one another in staggered disposition about said tubular burner member, a main jet orifice disposed within said tubular burner member adjacent said orifices, a pilot jet orifice disposed adjacent the upper end of said tubular member, and means for supplying both the main and pilot jet orifices of each of said burners with gas under pressure, the gas supplied to at least said main jet orifices being at a pressure in excess of one p.s.i.

References Cited in the file of this patent UNITED STATES PATENTS 754,747 Clewell Mar. 15, 1915 1,164,058 Bayne Dec. 14, 1915 1,668,001 Bolling May 1, 1928 1,854,893 Farrer et al Apr. 19, 1932 1,920,186 Carter Aug. 1, 1933 2,183,855 Mansky Dec. 19, 1939 2,197,325 Spikes Apr. 16, 1940 2,216,075 Henderson Sept. 24, 1940 2,268,591 Holm Jan. 6, 1942 2,279,097 Stark Apr. 7, 1942 2,357,575 Benz Sept. 5, 1944 2,472,534 Home June 7, 1949 2,534,618 Moore Dec. 19, 1950 2,569,084 White Sept. 25, 1951 2,783,988 Garner Mar. 5, 1957

Images