US2531148A - Drying furnace - Google Patents

Description

Nov. 2l, 1950 D. J. MCGOWAN ETAL 2,531,148

DRYING FURNACE Filed Dec. 19, 1946 5 Sheets-Sheet 1 /,/////////////l /f/f/ N ov. 21, 1950 D. J. MGGOWAN ETAL 2,531,148

DRYING FURNACE Filed Dec. 19, 194e 5 sheets-sheet 2 Nov. 2l, 1950 D. J. MCGowAN Erm, 2,531,148

DRYING FURNACE Nov. 2l, 1950 D. J. MGGowAN ETAL 2,531,148

.DRYING FURNACE Filed Dec. 19, 1946 5 Sheets-Sheet 4 Patented Nov. 2l, 1950 uni-run.. STATES PATE-NT oFFlcEf DRYINGV FURNACE Donald-.,L. McGowan and Anthony Ferdinand 1rrtll'er, Milwaukee, Wis., and Loren Ll Hebh'erd, Chicago; lli., assignors to The S. Gb'errnayer Coz, Chicago, Ill., wcorporation'ofhio' Appiicauon--neeemter19, uns; serial No.. 717,262

Thepresent invention relates .to dryingifurnaces used,..for example, in, supplying large volumes of uniformly heated gases for drying maltwherethe gas temperature iscontrolledwithin a limitedburned in. this ichamber.. has. been... completed,l a

relatively largevolume of cool-air isintroduced intothe stream ,ofv hotgases .so .-as. toprovide the necessarylarge volume .of hot dry gases required for thedryingperations. This introduction of cool air shouldbe broughtabout as soon...

as possible. after. the. combustion of the fuel. is

complete `so that. the temperature. of the gases-- entering the. stack.. are sunicien'tly low. to e1imi.

nate .thenecessity oiusingia large-amount ofre-4 fractory. lining` in the stack.. Thus it ispr-imarily.V in the combustion..zone. that refractory-material must .be used and fthe problem, of replacement .of

such material istherefore .minimized considerably. Complete combustion of theiuelis also guaranteed sov that. v.the .opportunityfor .unburned or partially burnedgases -toenter the stack is remote and therefore-thedanger ofcontaminat- I ing. the. malt.,. or otherv material `to .bei dried, is reduced to a minimum..

In addition .to `the .foregoing .objects ,of the. in

vention it isintended to. providea dryingfurnace that furnishes uniformly heated gases tcl-the drying room. Devices. previouslyv used for.. drying malt supplied gases vto thedryingroom in. avery.

uneven temperature condition; i.- e., the temperature of. the gases passing over some of the malt.

was so hot as to yburn the material whereasin other parts of the. dryingroom the gases were too .cooltoeiect complete. drying@ The present invention overcomes thisdimculty by providingadevice that furnishes to thefdrying roorrigases.-A

having even temperatureconditions. .throughout all parts of its volume.

The foregoing-constitutefsome-.of the principal. objects., and advantages ...of ...the present. invention.r and others 4.will'loecome apparent from. a-reading...

of the ,following description..

In the drawingsz.

Fig. 1 isa vertical,y sectionalyiew through furnace andJa` portion ofthe stacl...showing.anI

embodiment of thepresent invention.; v

Fig,V 2 isA a..horizontal," sectional .view,throueh the..furnace,..the view-beingtaken onthe linev Fig. 3. is .a.vertical, .sectional viewthrough fthe:

furnace and aportionof` the stack, the view.b.e. ing taken onthe Vline 3-.-S.of1Eg-. l;

Fig. 4 is..a..vertical, sectional View throughithe.l furnace, the vieu/:being taken on the -1ine.4-4= of'.

Fig. 1; and

Fig. 5 is. a diagrammaticv view illustrating thev entire .drying apparatus embodying.- theY invenf..

tion., and. including..,the.furnace, the.. stack.: and

the blower.

For. purposes.- of .illustration one embodiment ot therpresent. .invention .has.been selected in .-com= pliance with the requirements set forth in the-f.

Revisedtatutes. Itis recognized,-.ofcourse, and

will be apparent .toene skilled in theart, `that.A manymodications mayfbe madein 'the specifica` device Yas shown without 4departingfrom the. in-.

tended scope ofthefinvention The invention yis Y. concerned. with. providing: a

relatively large quantity-of. hot dry air-:to a room, or 4other enclosure for drying purposes. been provento .be exceptionally useful. .and satisfactory inconnection withthev` drying ofmalt.4

Reierringto Fig.. 5mi-the drawings the dry? ing room or enclosure isindicated at: I5.. The

furnace for producingthe necessaryfheat .for..the. gases ..is...indicated aatf-i aand.iamstaclr4 I 'I.,commu. nicating.. withy this` furnace iiin conveysthe: hot gases to the ,drying room 15.- A suitable. bloweror fan. I 8.,may beemployedfto. move the-required..

volume of hot.. gases through-thadrying room.

Referringmow. to..Fig. l.. the furnacelaas."

shown generallycomprises a. pair of combustion chambers -or zones mand 2Q aand., intermediate dilution .chambers vorzones 2l. and.. 22 forl each.. of the combustion. chambers... The stack-I'I-rises., above the .furnace and; the. dilution.. `chambersl l and 22..empty.into thestacks.

The. furnace.. I 5 yand the' various ,chambers |91 t0.22.inclusive are. formedbyapair offside walls:m 23. and 2d .(Figs..2andf.3), end` Walls 25.,and.2G-,.. a door-generally.indicatedat. 2l andsuspended.. Thev 1roofs Y-2S...and-

archess or.. roofs.. 2B..and J9. 29 bend-upwardly as at `Stand 3|. respectively and.join..with. the. vertieallwallsof stack 'L Each. of .thewend walls 25..and..25 is 'provided'. With a fuel inlet port 32 for introducingifuelitov be burned.. into.. thecorresponding` combustion chamber I 9 y.or 20. As .shown in. Fig.. 3 each of.. the. end -walls f2 5 .anda 6 is.. alsoy .provided `.with air ports. 33 for-introducing,airintortheeombustion chamberl abovethe.fuelinletport 32.- Addie,

tional. ain inlet ports,arelrprovideduadjacent tolV` 3 the bottom of the furnace and passages 34 are provided in an upwardly inclined portion 35 of the floor 2l of the furnace. These passages 34 are disposed closely adjacent to the fuel inlet port 32. Thus fuel such as gas, is introduced through the port 32 along with air into the combustion chamber 2D and is mixed with the necessary additional quantity of air through ports 33 and passages 34 and burned in chamber Zl. It is intended that the burning of this fuel be restricted v primarily to the combustion chamber 29 so that by the time this fuel, which is traveling toward the stack l'l, reaches the diluting chamber 22 it is substantially completely burned.

The fioor 2l' of the furnace adjacent to the center of the furnace is inclined upwardly in opposite directions as at 35 and 3l, meeting at 38 adjacent to the center line of the furnace so as to provide an inclined face 39 that serves to reflect heat toward the gases leaving the combustion Zones. Each of these inclined faces 39 is provided with a plurality of passages 40 for introducing air into the furnace and these passages are adapted to discharge air into the gas stream approximately at right angles to the direction of movement of said gas stream. The air thus admitted into the gas stream produces a churning action so as to eiect rather complete mixing of this cooler air with the hot gases leaving the combustion chamber 2B. and thus cool the hot gases and also provides additional air that may be required to complete the combustion of the gases in the event the combustion was not completed in the combustion zone.

It will be noted in the drawings that the combustion chambers |9 and 20 and diluting chambers 2| and 22 are lined as at 4| with refractory material. The stack I1 may be made out of rebrick or some such suitable material but because 1 of the diluting and cooling of the gases in chambers 2| and 22 it is not necessary to provide a refractory liner on the inner walls of the stack.

Referring now to Fig. 3, directly above the diluting chambers 2| and 22 and disposed adjacent to the upper ends of the curved upper walls 39 and 3| of these chambers is an arch member generally indicated at 42. This arch 42 comprises a hollow box-like portion 43 that extends entirely across the open ends of the diluting chambers. This box-like portion 43 provides a passage 44 therein through which air may be passed for purposes of cooling the arch member. This air enters the stack gases through apertures 43a. The outer exposed faces of the arch 42 are lined as at 45 with a suitable refractory material. Side openings 46 are provided just below the arch 42 so that air and hot gases directed from the furnace to the stack may pass therethrough and enn ter the stack. The direction of gas flow is changed by the arch 42 and is induced by the blower to flow through the openings 46. The walls 23 and 24 are provided with passages 23a and 24a respectively that open out adjacent to the bottom of openings 46 and a large amount of cool air is introduced into the gas stream through these passages. This air serves to further dilute and cool the gases and also to cool the furnace walls 23 and 24.

It is to be noted from Fig. 3 that the air introduced through passages 23a and 24a into the gas streams passing through openings 46 is directed at right angles to the direction of flow of the gases. This air is introduced through doors 40a (Fig. l) and serves additionally to cool the side This serves to dilute i l passages 49.

Walls of the furnace. Again this produces a churning action which effects thorough mixing of the cool air with the gases.

Referring to Figs. 1 and 3 the stack comprises walls 41, 48, 49 and 50. Walls 49 and 58 are spaced laterally with respect to the walls 23 and 24 respectively of the furnace. Auxiliary ring equipment such as a hand red grate and grate opening generally indicated at 5|, may be disposed in each of the spaces located between the stack walls 49 or 5|] and the adjacent furnace wall.

After the mixture of gases and air leaves openings 46, their direction of oW is again changed so that the flow is directed upwardly. At this point of direction change additional air is introduced into the gas stream, this air entering through the auxiliary firing equipment indicated at 5| and rising into the gas stream.

In each of the stack walls 49 and 59 is an opening 52 (Fig. 3) through which air may pass so that a relatively large volume of air may be introduced in to the stack through these openings. This air is also introduced into the gas stream substantially where the directionof gas flow is changing.

Thus it is to be noted that cool air is introduced into the gas stream at each point where the direction of gas flow changes. This produces a churning action of the hot gases and the cooler air in these regions so as to effect a complete mixing of the two gases thereby providing uniform temperature conditions throughout the mixture.

Suitable supporting members such as channels and I- beams 53 and 54 respectively may be employed for supporting the arch 42 together with additional supporting structure, such as columns 55.

In the normal operation of the present device fuel to be burned together with air is introduced at opposite ends of the furnace through fuel ports 32 and sufficient additional air is introduced into combustion chamber 20 through the passages 33 and 34 to support the combustion of this fuel. As previously mentioned it is intended that substantially all of the fuel is to be burned in the combustion chamber 20 and as a result of the burning of this fuel, gas at a high temperature is produced in the combustion chamber. Movement of this hot gas is induced along the furnace by the fan indicated at I8 in Fig. 5 and is brought in contact with air that is entering the furnace through the passages 40. Doors 60 in the furnace side walls introduce this air into the space below Sufficient turbulence is created in the hot gases and the air as previously mentioned to create a rather thorough mixing of these two gases in the diluting chambers 2| and 22 of the furnace. In this manner not only is additional air provided to insure combustion of the gases,

if such is needed, but the temperature of the hot gases is reduced considerably so that by the time this mixture reaches the upper end of the mixing chambers 2| and 22 its temperature has been greatly reduced. This mixture of gases, directed by arch 42, leaves the furnace proper through the openings 46 (Fig. 3). Relatively large volumes of air are introduced at these points through passages 23a and 24a and from the auxiliary firing region 5|. Sufficient turbulence is created in this gas leaving the furnace so that it is thoroughly mixed with this relatively large volume of cool air entering the gas stream. The cool air entering the stream through openings 52 is in suiiicient quantities to bring the ultimate temperature of the gases to the desired level. Thus the gases rising in the stack are thoroughly mixed and are brought to the drying room I5 at the required uniform temperature. The gases now are drawn through the malt to be dried in the drying room l5 and are then exhausted by fan I8 into the atmosphere.

Thus relatively large volumes of air are introduced at a multiplicity of positions in the furnace and stack in a manner not only to effect thorough mixing of the air, but also to cool the refractory materials in the furnace and stack so as to reduce the maintenance.

We claim:

l. A drying furnace having combustion chambers with diluting chambers therebetween and above the combustion chambers and a stack about said furnace having a drying room therein above said chambers, the top wall of the respective combustion chambers leading into the respective dilution chambers, the walls of said combustion chambers having fuel and air inlet openings, a floor for said furnace having air inlet ports adjacent said fuel inlet ports, said floor having a centrally located raised portion below the diluting chambers providing inclined faces substantially .facing the combustion chambers and deflecting upwardly towards the diluting chambers the combustion gases moving from the combustion zones,

said inclined faces having ports for introducing air into the furnace to mix with the gas stream at an angle to the direction of movement of said stream to cause turbulence therein; a baille positioned across the diluting chambers for changing the direction of the gas stream, passages in the ,2.

furnace around Said baille and leading to the stack to carry the diluted gases to said stack, air intake iiues in the furnace walls and ports leading from said walls to the baffle to lead cold air thereto at an angle to the direction of ow to mix with .zr

the gases flowing from the dilution chambers to the stack to cause further turbulence, ports in the stack Wall at a height substantially coincident with the height of the baille to introduce air into the stack where the cooled gas stream from the CII 6 dilution chamber passes around the baffle to cause still further turbulence and to further dilute the combustion gases before they pass to the drying chamber.

2. A drying furnace having spaced combustion chambers and a dilution chamber at a higher level therebetween, a oor for said furnace having a centrally located raised portion providing inclined faces to deflect gases from said combustion chambers to said dilution chamber, a baille across the top of said dilution chamber, a Stack around said furnace, said baille deflecting the gases from said diluting chamber to said stack, cool air inlet ports in said furnace at each deflection point arranged to direct cool air into the now of combustion gases to cause a mixing thereof, and an air inlet in the stack adjacent said baffle to introduce additional cool air into the stream at an angle to the direction of flow to cause further mixing of the diluted combustion gases around the baille to cause further turbulence and further dilute the combustion gases, said deflection points and air inlet ports occurring at successively higher positions in the furnace along the path of flow of the gases.

3. A furnace according to claim 2, in which the baffle has an air chamber throughout its length, a cool air inlet and an outlet for said air, the outlet leading to said stack.

DONALD J. MCGOWAN. ANTHONY FERDINAND HALTER. LOREN L. HEBBERD.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 1,522,914 Schumacher Jan. 13, 1925 1,676,070 Bluemel July 3, 1928 1,703,635 Ransom Feb. 26, 1929 1,711,273 Manker Apr. 30, 1929 1,832,151 Stein Nov. 17, 1931 2,398,654 Lubbock Apr, 16, 1946 2,445,466 Arnhym July 20, 1948

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