US2438407A - Heating plant and furnace - Google Patents

Description

March 23, 1948*.

J. A. KREUSER HEATING PLANT AND FURNACE 2 Sheets-Sheet 1 March 23, 1948. J. A. KREUSER HEATING PLANT AND FuRNAE 2 Sheet's-Sheet 2 Filed April 13,' 1944 zfecz @q1/:f

PatentedA Mar. 23 1948 UNITED STATES PATENT OFFICE v HEATING PLANT AND FURNACE' John A. Kreuser, Chicago, Ill.

Application April 13, 1944, Serial No. 530,901

22 Claims.

rlhis invention relates to heating plants and furnaces, and is particularly concerned with an automatically operated smokeless furnace using a solid fuel.

The principal object of the invention resides in the provision of a furnace having features adapted for any desired plant conditions, but particularly for domestic heating systems including hot air, hot Water or steam furnaces, and further adapted to burn solid fuel, such as finely divided coal, substantially without formation of smoke, regardless of the volatile contents of the coal, and substantially without formation of clinkers, regardless of the caking qualities of the coal.

This object is in part realized by the provision of means, in combination with a rebox and a grate, forming a gas producer or generator, in-

cluding a mechanically operated heat-controlled retort for successively converting amounts of coal into coke and thereupon successively completing the-combustion of the resulting amounts of coke on the grate.

The combustible gases originating in the generator or producer incident to the coking of the coal and resulting from the burning of the coke on the grate are conducted through the medium of a mixing device which operates somewhat in the nature of a torch, into a separatecoinbustion chamber forming the principal heat-producing unit of the furnace. The combustion of the volatile contents of the coal is completed in this combustionvchamber, thereby substantially avoiding the production of smoke. A plurality of serially related communicating combustion chambers may be provided if desired, each receiving combustible gases through the medium of a mixing device as indicated.

vThe above intimated arrangement makes it possible to operate the generator, including the retort, and the rebox, at a temperature belowI v the fusion temperature of the ash, thereby preventing the formation of clinkers.

Further objects and features relates to the provision of means for automatically feeding coal to the furnace and removing the ashes from the ash pit thereof.

Additional objects are concerned with the provision of means for timing the coal feed and ash control as well as ash removal operations so as to satisfy variable needs in accordance with the requirements that may result from seasonal changes or from other contingencies that may arise in the effective production of heat.

Means are provided in accordance with certain other objects of the invention for automatically controlling the air feed into the rebox, and through the furnace, in timed relation with the operations resulting from the feeding of the coal and combustion thereof, and means for coordinating the coal feed, the ash control and ash removal, including shaking of the grate, and the air -feed, so as to obtain entirely automatic and efficient operation of the whole furnace as may be desired or required by operating conditions of any one plant produced in accordance with the invention. p

Further objects relate to the provision of a structure forming a unit for heating a desired medium, e. g., air, which operates in the nature of an economizer, whereby the hot gases are conducted around the heating unitV in a labyrinth path including the entire heating surface of the unit.

These and other objects and features will be described below in detail with reference to the embodiment of a furnace adapted for domestic air heating purposes as illustrated in the accompanying drawings. In these drawings,

Fig. 1 is a. plan frontal View of an example of a furnace made in accordance with the invention;

Fig. 2 represents the furnace Fig. l with the front wall removedY and some parts broken away so as to show details;

Fig. 3 shows an end view of the furnace with some parts in section, taken approximately along lines 3--3 of Fig. 2; and

Fig. 4 is a schematic operation and wiring diagram showing essential parts of the furnace and means for obtaining the automatic control of' individual functions and the coordination thereof for the purpose of forming an automatically harmoniously operating unit.

Like parts are designated by like reference numerals throughout the drawings. Elements and details which may be presumed to be Well known will be discussed only to the extent required for conveying an understanding of what is believed to be new.

The illustrated furnace has a housing comprising a front wall II, an air intake I2 which may be provided with or may connect with a suitable air intake control fan, a damper or exhaust duct I3 leading to a chimney I4, and a distributor hood I5 provided with ducts I5, I'I for distributingthe heated air as may be desired. Coal from a suitable bin is fed to the furnace by means of a conveyor contained in a casing I8. The conveyor is operated by a chain I9 engaging a, driven sprocket 20 and a drive sprocket 2l on a shaft which also carries a.y gear wheel 22.

An ash removal conveyor 23 is provided underneath the ash pit 24 ofthe firebox 25. rlhis conveyor is operated by means of a drive including a driven pulley 26 and a drive pulley 2l actuated by the motor 28, and deposits the ashes in a suitable receptacle 29. The motor 28 also operates a crank 30 for shaking the grate in the rebox. A gear box |25 may be provided between the pulley 26 YVand the conveyor 23, as shown in Figs. 1 3. v

On the front wall of the furnace are mounted certain control means including the retort motor RM, also indicated by numeral 3|, the gear .box

32, and the control device 33. The motor 3! may` .be provided with a gear reducer indicated in Fig. 1 at 3|a. These devices .control thecoal feed,

the retort which will be presently described, and` numeral 35,` and a damper control device DC,

also numbered 36. The timing controlis adapted for Setting or adjusting the frequency of operation of the coal feed coordinated with the frequency of operationof the retort motor, and the damper control governs the automatic actuation of the air supply in coordination with the needs of the furnaceas determined by the coal feed and by the actuation of the retort motor. A lever lilla is provided for manual control of the damper as shown in -Fig.,1. Y i

VNumerals 45;, di in Fig. 1 indicate cleaning doors through which access may be gained to certain interior sections of the furnace. Numeral 42 denotes the nre door; '43 theash pit door; and ld the air intake for the reboX. kThe air intake may be provided with manually adjustable slots or openings.

The furnace, .as particularly shown in Fig. 2, is provided Witha transverse end wall El) forming with the transverse intermediateY wall 5l the frontal section comprising the inclined coal feed 5,2, the retort the generatoror producer section 5d, and-the rebox 25 which is equipped with a suitable grate 55 disposed above the ash pit 2d. Predetermined periodically Ysupplied amounts of coal are successively converted into coke in the retort 5-3, and these .amounts of coke are periodically fed to the nrebox 'for complete combustion of the combusible solid constituents of the fuel.A

An angular transverse wall partition 5l forms ducts 5S and 59, for conducting downwardly traces of gases which enter thefeed and the generator retort sectionk to mix with ygases .produced in the rebox above the grate 5E for Vpassage through the openings 8i). The lower section of the `transverse wall 5l forms with the 'partition 60 a combustion chamber 6I which receives for complete combustion, of the volatile contents of the coal, the gases produced inthe coking'of the coal in the retort section v53, and in the burning of the coke on the grate 55. The gases are conducted into the combustion chamber 6l through the openings 80 in thelower 'portion of the wall torches, ejecting the hot gases for complete combustion into the combustion chamber 6|. `The ductV 59 Apermits the traces of gases which `enter the upper region of the feed and retort section to mix with the gases fromthe retort and from the grate to `ilnd their' way to athe passages `8l? because these are the only passages under suction These openings operate in the manner Lof 4 i from the chimney. A single combustion chamber is shown. It is understood, however, as previously mentioned, that a pluralitir of combustion chambers may be provided, each receiving gases through a mixing device including gas inlets or jet openings such as indicated at 80.

An end wall 62 closes the structure at the right,

as seen in Fig. 2. The walls 5-5I, till-62 and the Vpartition 51 may be made of heat-resisting material of the type usually employed in furnace structures. Y

.A shield 63 projects from the partition wall Eli and forms with one wall 64' of the air duct 65 'a transverse 'space 66 for receiving the hot gases coming from the combustion chamber El in the VVdirection indicated by the full-line arrows.V The l wall 6ft extends transversely through the furnace Y gear wheel meshes with the gear wheel 22, therestructure. VThe hot gases are thus conducted downwardly through the space 66, washing the surface of the wall 6d of the air duct. They are then directed through openings '1.01, .provided on Opposite sides inV the wall 64 Vat'the .bottom thereof, into the Vspace 61 formed by the wall 5S of the air duct and .by .the end wall v620i the furnace, and into like spaces formedby front and rear walls Vof the air duct 65u The gases escape through the damper or exhaust duct i3 into the chimney l4 Y The arrangement including the air duct v and the walls `(50, 63 and -62 operates in the Ynature of an -economizer. The air duct 35 forms'a centrally positioned chimney-like structure within the space formed'by the front and vrear walls, and by the walls yEill,6;3.62-, 'and the hot gases wash the outer surface of this air 'duct on all sides moving first downwardly along one side Wall (64) and then upwardly around the Vremaining three side walls, for escapeytlirough the exhaust or damper duct I3. Air entering through the intake l2 and moving through the air duct 65 in the direction of lthe dotted arrows is thuseffectively heated.

It is deemed desirable to mention at this point that the furnace is shown as an air-heating unit only for the purpose of convenience and to give an example of Vhow the invention may be used in practice. The structure 'mayV be adapted for Water-heating, steam-producing, and like. .purposes.`v Y Y Inside of the generator or producer chamber 54, disposed .between the walls 50 rand 151.., isa

transverse partition 1|. O ngeach side of this partition is .a rotatable shaft having `vanes `in'. the manner of a star wheel andy formingV on each shaft eight pockets, eachY pocket occupying .a sector of 45. These two -retortrotor members are indicated by numerals 'l2 and lf3. They constitute movable Supporting means for receiving y motor 3l (RM), thefshaft also carrying a 'gear wheel 'll Aindicated vin Figs. 1 and 3. Theglatter by rotating they shaft of ,the-other rotor 13. The

direction of rotation.isindicatedin Fig. 2 by arrows, The operation, ias will bepresently described, is such that-the, rotors l2, 'lf3rarealways rotated through anarc'suiicient to allow emptying ofionefpocket of ea'ch wheel-downwardly into the rebox. Two of the buckets `'of each rotor, that, is, two of its segment-shaped sections, are iled .with VVcoarfromv the vconveyor containe'dzin the housing 8 over the coal feedinclined hopper surface 52. Rotation of the rotors 12, 13 also causes rotation of the drive sprocket 2| and consequently of sprocket 20 connected therewith by the chain I9, for the purpose of feeding to the furnace an amount of coal to compensate for the amount of coked coal permitted to drop into the rebox.

Baies such as 15 and 1B are provided above the star wheels or rotors 12, 13, a row of lsuch baffles on each side, and the baffles in each row are movably mounted on a shaft secured in the side walls of the structure as shown in Fig. 3. The purpose of these baffles is to conne coal feed to the retort, i, e., the structure above the rotors, but in a non-rigid manner to permit equalization required by unavoidable shifting and packing of the coal. The baffles may be made of suitable stone or ceramic material.

The coal is fed into the retort 53 between the baffles 15 and 16, dropping into the buckets formed bythe corresponding upper sectors of the rotors 12 and 13. Heat radiating upwardly from the rebox causes coking of the coal in these pockets, and these pockets therefore may be considered part of a retort and a generator or producer. Whenever the rotors 12 and 13 are rotated as described, two pockets, i. e., one pocket or sector of each rotor, will empty the coked coal downwardly into the firebox where the coke is burned on the grate to obtain complete combustion of the combustible solid constituents of the coal. The rotation of the rotors is periodic and the angular displacement thereof always amounts to 45, or one-eighth of a revolution of each rotor.

The gear wheel 11 operated by the retort motor 3| meshes with a gear wheel 14 (see Figs. 3 and 4) mountedon a shaft extending from the gear box 32 disposed above the retort motor, as shown in Figs, 1 and 3. In Fig. 4, the arrangement of the gearbox 32 and its gear wheel 11 is reversed with respect to the retort motor 3|. This, however, is done merely for the sake of convenient schematic representation.

The gear box 32 contains known gear means adapted to drive a trip lever 18 in a desired ratio with respect to the speed of the gear wheel 11, which ratio is adjustable by means of a lever 19. It is thus possible to rotate the trip lever 18 once for a given selected number of rotations of the gear wheel 11, i. e., once for a selected number of revoluti-ons of the shaft of the retort motor 3| or, conversely, once for a selected number of operations of the rotors 12, 13 by the retort motor 3|. For example, the device may be adjusted so as to obtain one revolution of the trip lever 18 to every thirty-six operations of the rotors 12, 13. It is assumed in such case that the retort motor is adjusted to produce 1/2 R. P. M. and that it is operated every five minutes to rotate the star wheels 12, 13 by 45 or one-eighth of a turn, which would result in placing the triplever 18 once in every three hours in operative position with respect to the trip arm 8|.

The coaction of trip lever 18 actuated by the gear box device 32 with the trip arm 8| governs the frequency of operation of the ash control, that is, the shaking of the grate 56 as well as the actuation of the ash removal conveyor 23. When the arm 8| is operated it closes the contact 82 shown in Fig. 4 and thereby completes a circuit for the motor 28 over a timing switch 84, the circuit including the conductor 85 from one pole 85 of a current source and back to the other pole 81 by way of the conductor 89. The timing switch S4 permits operation of the motor 28 for a definite adjustable time interval, for example, for the same time interval of fifteen seconds for which the retort motor is operated to rotate the retort rotors 12, 13. The manner in which the ash control functions is apparent from Fig. 4 and will be presently described more in detail.

The timing control device 35, as shown in Fig. 4, includes the adjustable time switch 9U, a relay 9|, and the contact switch and timing provisions 92 and 93. The time switch may be set to actuate the retort motor once at definite intervals, for example, once in ve minutes, once in fifteen minutes, or once in thirty minutes, and in each case for denite duration, e. g., fifteen seconds. The retort motor which may be set at 1/2 R. P. M will makek upon each actuation one-eighth of a turn and will empty the two buckets or sectors of coke into the flrebox. Operation once in every five minutes may be adjusted for very cold weather; once every fifteen minutes may be sufcient for medium cold weather; and once every thirty minutes may be satisfactory in mild Weather. These data are not intended to indicate absolute values; they are noted for explanatory purposes.

The operation Iof the retort motor 3| may also be initiated independently of the timing control device 35 by a thermostat 95. The timing device 91| will be disconnected, in a manner to be presently explained, whenever the thermostat takes over the control.

The damper in the exhaust duct I3 comprises a simple valve indicated by numeral |03. This valve may be manually set b-y means of the hand lever lilla; it is normally held in nearly closed position, as sho-wn in Figs. 1 and 4, by means of a weighted lever ||l|. This lever may be raised for placing the valve in open position, as shown in Fig. 2, by means of a crank operable by a motor |33 which is operated whenever the retort motor 3| is actuated, and automatically opens the valve loll.

It will thus be seen that air is supplied to the -rebox in throttled manner during the burning of coke on the grate, but that air supply is increased for a time interval subsequent to the operation of the retort motor 3|. The damper motor |03 stops when the crank |02 has made a turn and starts again, after the stopping of the retort motor, to close the valve |00 slowly, whereupon it is disconnected after the valve is put again into the normal partially throttled position shown in Figs. 1 and 4. This damper control admits a greater amount of air to the combustion chambers during the period of intense gas-producing, that is, during and shortly after the time when coke is fed from the retort into the rebox for burning on the grate therein.

The operation will now be described with particular reference to Figs. 2 and 4.

It will be assumed first that the furnace is to be started, as would be the case upon completing installation thereof. The re in the rebox 25 is prepared in the usual way by piling up fuel on the grate and igniting it. This is done through the door 42 (Fig. 1) of the firebox. The ash pit door 43 is open. The damper valve |00 in the exhaust or damper duct I3 is manually placed in open position by -operating and suitably locking the lever lilla. For the time being the airport door 44 remains in closed position. The draft resulting upwardly through the grate and thence through the mixer ports 80, combustion chamber 5|, and through the channels of the economizer heater unitandthe damper duct into the 'chimney, is self-explanatory. A

After the reV has been'st'arted; the switch Hill of the main circuit show-n in FigA may be closed to prepare for the 'automatic operation of the furnace. Coal rnust now be supplied tothe retort 53, that is to sayQto the buckets formed by the upwardly and inwardly directed sectorsrof 'the retort rotors *i2 and i3. For 'this purpose the switch lll is manually closed so 'as to start the retort motor 3i from the V'pole 85 of the main line by way of switch lll, retort motor '35, and conductor H2, back to the pole 81 of 'the main line.

The retort motor, having been set lfor -1/2 R. P. operates, rotates the rotors 12 and 13, and also operates the kcoal conveyor in the housing lo by Way ofthe chain IS. An amount of coal is thus supplied to the retort 53. -The switch l l l is then opened andthe retort motor stops.

The timing control vdevi-ce 35 isnow set to the desired operation, which will depend on Weather conditions. It is assumed, for the purpose of explanation, that the furnacev is to be set for very cold vweather in which fuel is to be supplied for combustion at intervals of 'five minutes. The timing control 35 is set for five-minute operation, in which position it will supply kcu'rrer'it to the retort motor 3i for fteen seconds every Vrive minutes, to rotate the retort rotors in each period of operation by 45, `or one-eighth of a `turn in the direction of the arrows shown in Fig. 2. YAccordingly, during such periodic operation the retort rotors l2 and Y'i3 will empty the fuel disposed in one bucket or sector of each rotor downwardly vinto the iirebox 25.

It is further assumed that for this loperation iit will be necessary toV remove the ashes every two lhours by shaking the grate' and simultaneously Voperating Vthe ash removal conveyor 23.V Phe :gear device 32 is for this purpose adjusted by .means of the lever 7S for a gear ratio of 3 to '1;' "that is to say, whenever the retort'rn'otor 3l makes one revolution; the trip lever T8 will make 4one-third of a revolution. The trip lever 18' will vtherefore engage and trip the trip oontactflever 8l of the ash control device once every 'two hours. The duration of oper-ation ofthe motor 28 which controls the grate-'shaking andthe operation of the ash removal conveyor 23 may be set byrneans of a switch 84 indicated in Fig. 4.

rThe damper valve Hill is put in normal position in which it is shown in Figs. 1 and 4, by vreleasing the Ymanual control vI D la, which wasv actuated upon starting the fire. The ash `pit door 53 is closed and therre door '42 is likewise closed; The door 4:4 contro-llingthe airports in front of the rebox is now opened. The size ofthe opening 'may be manually adjustable in the usual manner. The draft through the fur-nacediminishes and is now entirely through the rebox above the re on 'the grate 5S. The furnace is now set for automatic opera-tion and this :condi-l tion will continue throughout such operation.

Two upwardly and inwardly directed sectors or buckets of the retort rotors l2 and 13 are fil-led with coal. The hot gases developing Yin the firebox 25 and radiating upwardly into thefproducer or generator chamber cause a cokin'gY of the coal in the buckets or sectors of 'fthe retort' r-ot'ors.` The temperature in the fire/box is keptbelow the yfusion point of the ashes, due t'o 'the'col'd air current from 'the airports controlled by the door 44 sweeping 'through the flreb'ox'iab'ove the fuel on the grate Yinthe directionlof thefullfline arrows.

" The `,cornbustible gases developingin the retort incidentto thek coking of the coal and the gases developing in the 'iirebox incident 'to burning'of theV Vcoke, are collected, mixed, and escapeV rotates the Vretort rotors '52., 13 for VifteenV s'ec- .Y

onds so as to obtain a rotation or angular displacement of the fuel-supporting device, which is equivalent to one-eighth of a turn of each retort rotor. During this operation the coked coal in two buckets of the retort rotors drops' down into therebox. f

During and slightly after completion of this phaserof operation it is desirable 'to increasethe draft of air through the 4furnace for the'pur'pose of promoting the combustion of the amount of coke supplied to the grate. matically as follows :V

Whenever the slow-release relay Si isre'nergized (upon starting the fifteen-second periodic operation of the retort motor 3l), it closes'fa circuit for the damper control motor |03, from the pole 86 of the :main circuit by way of conductor "H5, contact IE6 of the relay Si in operated position, conductor 'i Il, closed contacts H8 of the damper control device, motor 593, and conductor l I9, bac-k to the other pole 87 of the main circuit. The damper control motor M33 operates slowly, turning its crank 62 and thereby lifting the weighted'lever Vitl to displace the damper valve i913 gradually into its open posi- -rn'ainta'ins open Vthe Contact 121.

tion, as illustrated in Fig. 2. This operation may consume a longer period than the uiteen-second period of operation of 'the retort motor 3l. For this purpose the relay Si 'is slow-releasing, as indicated, andmaintains the circuit 'overcone tact H after the retort motor `ii! has .stopped at the end of the fteen-second operating period.

The damper control motor i'is also equipped with a cam' i2@ which, .in the position shown, The contact 121 is closed 'shortly after Istarting operation off the vmotor it@ to rotate the crank 32. YNo result isroibt'ained at this time by the closing ofcontact i2! because vthe circuit extending from this contact by way of conductor H22 is open at Lthe normally closed contact Vi it vof the slow-release f 'relay 9i which isnow in operated position due to en'ergization of relay .9i inserieswithithe j The operation of; the damperjcontrol motor 3|. motor w3' therefore continues. Upon :displacing the crank E92 by 180'` theV damperrcontrol motor |33 stops because its circuiti's interrupted at contact H8 by the `cani lZ which ialsohas been ydisplaced by. Themaximum'amount of 'air is now supplied to the fireboxithrough the airports in thed'oor fifi Vfor burning'the amount of coke dropped 'onto theV grate by the operation 'of the retort rot'ors'i2 and l. f Y

The `slourelease relay A9i Vd'eenergizes after K awhile and places Contact Ulintothe normal position shown in Figj'.: A circuit :is thereby closed for 'the 4damper control motor fills which K The highest temperature 'in'lthe This is done auto-V extends from the pole 86 of the main line by way of conductor 5, contact I |6 in normal position, conductor |22, now closed contact |2|, motor |93, back to the pole 8l of the main line by Way of conductor H9. 'I'he damper control motor therefore rotates again and slowly places the damper -valve |99 into the nearly closed position in which it is shown. When the cam |29 reaches its normal position incident to rotation of the damper control motor |93, it interrupts the operating circuit of the motor by opening contact |2|. The damper valve is again in its nearly closed position. The air draft through the rebox is again throttled to a predetermined low which is sufficient for further combustion of the coke, as explained Ibefore.

The above described operation is repeated every five minutes for a predetermined adjustable period which may be, for example, two hours. At that time the gear device 32 has advanced trip lever 'i8 into engagement with the trip control lever 8| of the ash control device 33. When the trip control lever 8| is actuated, it operates the contacts 82 and thereby closes a circuit for the motor 29 which extends from the pole 86 of the main line by way of conductor 85, contacts S2, and the timing `device 84 through the motor and back to the other pole 8l of the main line by way of conductor 89. The device 8d is a timing means which may be set to maintain the circuit for a desired period, for example, fifteen seconds, in accordance with the setting of the operation of the retort rotors l2, 13. Accordingly, motor 28 will operate for fifteen seconds and rotate its crank 3D, thereby rocking the rocker bar |25 provided with rods which are in pivotal engagement with the individual grate members to rock these members so as to remove the ashes from the grate and drop the ashes down into the ash pit 24.

At the same time, the drive pulley 21 is operated by the motor 28, thereby rotating the driven pulley 26 to advance the ash removal conveyor 23, which removes the accumulated ashes from the ash pit.

In Figs. l, 2 and 3, the `pulley 29 is shown connected to a gear device |25 which in turn operates the conveyer 23. This gear device is shown in these figures only for the sake of convenient representation, the motor '28 being shown mounted at the foot of the end Wall 159. The motor may be mounted alongside the furnace housing, e. g., at the foot of the front wall and in that case the gear |26 is not required. The operation is direct, as shown in Fig. 4.

The correct ratio lbetween the number of ashremoving periods and the number of retort turns will always be determined by the type of coal delivered to the coal bin, that is to say, bythe amount of ashes that will remain after combastion of any one type of coal. The setting of the gear ratio in the gear device 32 therefore will have to be determined usually once in a heating season in accordance with experience data which may be furnished yby the manufacturer of the furnace. The ash-removing frequency may be set, as above described, -once for two hours, or different periods once in three, four or five hours, ozportions thereof, as may be necessary. The duration of operation in each period may be determined by the sfvvitch 8d.

In addition to the automatic control provided` 10 place which may be, e. g., remote from the furnace. Whenever the thermostatic control is made operative, which may be done by a manually controlled switch (not shown) and the temperature changes at the designated point from a desired mean, the control is taken over by the thermostatic device 95. Upon operation either to high or to low position, the thermostatic. device first opens the contact 93 and thus disconnects the normally operative timing device 90.

This operation takes place, e. g., when the thermostatic device responds to an increase of temperature beyond the desired mean. Inv this case the movable contact of the thermcstatic device95, as shown in the drawing, would be displaced in counter-clockwise direction. The operation has no effect except that further periodic feeding of coal to the furnace and further coincident periodic feeding of coke from the retort to the firebox is discontinued, due to the opening of contact 93. As soon as the temperature drops to the desired mean, the thermostatic device again closes contact 93 and the periodic automatic operation continues as described before.

If the thermostatic device 95 is affected by a drop in temperature, this will indicate that feeding of larger amounts of fuel to the furnace is desired, e. g., by increasing the frequency of operation of the retort motor 3|. In such case. the thermostatic device 95 again disconnectsthe normal timing control 90, at contact 93, and closes an alternate circuit over the timing device 92, which may be adjusted for a desired increased rate of periodic feed control. The circuit for the retort motor will now be periodically closed at a more rapid predetermined rate by the timing device 92. All other operations will proceed 'as previously described except, of course, that .the initial control circuit over relay 9| is controlled from the timing device 92 instead of from the timing device 90.

The device 92 may be set to increase the frequency of operation of the furnace, for example, from one fifteen-second operation every veminutes to one such operation every three or four minutes, or it may .be adjusted to increase the duration of each period, e. g., from fifteen Yto thirty seconds. In the latter case, twice theamount of fuel would be supplied for combustion to compensate quickly for the drop in temperature.

As soon as the desired mean temperature is restored, the thermostatic control 95 restores the normal operation by opening the circuit over the timing device 92, and also restores the control over the normally operative timing device $9 by again closing the contact 93.`

Changes may be made within thescope `and spirit of the appended claims in whichk I have defined what I believe to be new and desire to have protected by Letters Patent of the United States.

Iclairn:

1. A furnace of the class described having a housing comprising front and rear walls, an end wall extending transversely of said front and rear walls at one end thereof, an intermediate wall extending transversely between said front and rear walls in .spaced relation to said end wall generally in parallel therewith and forming with said end wall a generally vertically extending principal passage; projections extending inwardly of said passage `from opposite sides of said end wall and said intermediate wall, respectively, and defining in said passage (ci) a bottom chaml1 ber forming a-iirebox, (b) a retort chamber above said firebox, and (c) afeed` chamberabovefsaid retortchamber; a rotatablemember in'A said retort chamber having vanesv forming pockets. tor receiving from saidfeed chamber a r solid'fuelwhich is.. substantially converted into coke by the. heat radiating upwardly into said retort chamberl from saidreb'ox; amotor for actuating said rotatable member so as tofeed'said coke. downwardly.- from said retort chamber into-'said reboi; for burning on a grate therein; partition means` disposed transversely of saidr front and rear walls and extending upwardly from the top projecti'ononfsaid y intermediate wall forming withv such projection and with. the inside of said'intermediate wall a space within said principal passage above said retort' chamberv for receiving combustible gases moving. upwardly therefrom; said 'gases moving fromfsaid space through an opening'f'ormed in said top projection on said intermediatev Vwall downwardly within saidf principal `passage generally along the intermediate wallY for intermixture with and'f'or'escape together withA combustible gases developed in said rebox through ducts formed in said intermediate 'Wall' substantially at the horizontal level. of' saidV iirebox;` anda third transverse wall extending between said front and rear'walls in spaced,V relation to said intermediate wall forming a combustion chamber for receiving the mixture of combustible gase's for complete combustion therein. Y

2. The structure dei'ined in` claim 1, together with means for periodicallyactuating saidrnotor for the purpose. of rotating said rotatable member'to release from the pocketsrformed by the vanes thereon the coke contained in such pockets for burning on thegrate in sai'diir'ebox. i

3. The structure deiined in cl'aim'i, together with feed means for supplying tofsaid' feed' chamber solid fuel for deposit in and for coki'nginlthe' pockets formed by the vanes on said rotatable member in said retort chamber, means forperiodic'ally actuating said motor for theI purpose of rotating said member to.v release from saidf'poclr-- ets the coke contained therein for burningV 'on' the grate in said iirebox, andi means. governed by saidmotor'upon each periodic actuationv thereofV for operating said feed means tol 'supply an amount of solid fuel for deposit in and for ticking in thepocketsof said rotatable member which amount corresponds substantially to the amount gf cok'ed'fuel releasedtherefroml into said fire- OX'K.. i Y A 4. The structure denedr in claim 1, together with variably adjustable timing'meansl` for-:actuating Vsaid motor periodically Vfor the Vpurpose of rotating said rotatablemember to release from the'pockets formed by the vanes thereon the coke contained in such pockets for burning'on theY grate in said iirebox, an ash pitfor receiving the Vashes from said fireboxf a conveyor forremoving the ashes from the ash pit, a motor for operating said conveyor, and means governed by the first-named motor, which actuates saidrotatable'mernb'er, in variably adiustable timed'rela tion therewith', for periodically operating said conveyor-operating motor. i V5.Y Thestructure de'nedin claim 1', together with a variably'adjustable timing device 'for actuating said motor4 periodically for the purpose of rrotating said rotatable member to release periodically from the pockets formed by the vanes thereon predetermined amounts of coke contained in such'p'ockets for burning Von the grate in Said'rebOX, one of thepwalls of the furnace housing having air portsformed therein on a horizontal level; which extends above the grate in said iirebox for admitting air thereinto, means forming a duct for withdrawing Vfrom said furnace exhaust gases, a valvein said duct, Vmeans kfor normally maintaining said Valve in relatively throttled position, whereby a relatively smallY permit increased amounts ofrair to be drawn' throughv said rebox during periods of operative actuation of said motor and consequent release of amounts of coke into said firebox,

6. The structurev defined in claim l, together with a variably adjustable timing Ydevice-f or actuating said motor periodically for the purpose of rotating said rotatable member to release periodically from the` pocketsY formed by the vanes thereon predetermined amounts of coke contained in such pockets for burnin-gr on the grate in said nrebox, one of the walls of the furnace housing having air ports formed therein on a horizontal level extending above the grate in such rebox for admitting air thereinto, means forming a duct for withdrawing from said furnace exhaust gases, a valve insaid duct, means for normally maintaining said valve in relatively throttled position, whereby a relatively small amount of air is normally drawn from the .said

air ports through said rebox above the `fuel burning on the grate therein, means for operating Vsaid valve, means governed by said timing device for periodically actuating said valve-operating means for the purpose of opening said valve to permit increased amounts of air to be vdrawn Y throughsaid firebox during periods of operative actuation of said motor and consequent release of amounts of coke into said rebox, and *meansV controlled by said valve-operating means for returning said valve to normal position subsequent to stopping of said motor.

7'. The structure defined in claim 1, together e with a variably adjustable timing device for operating said motor periodically in predetermined successive intervals of set duration for the purpose of rotating said rotatable mem-ber to release periodically from the pockets formed by the vanes thereon predetermined amounts of coke into said irebox, additional timing means for controlling said motor to operate-in accordance with successive intervals of differentY duration, a thermostat for governing said additional timing means,

and switching means governed :by said thermoi stat for disconnecting said iirst-named timing device upon effecting the operation .of said additional timing means. Y

8f. The structure dened in claim ,1, together with a variably adjustable timing device for operating said motor periodically Vin predetermined successive intervals of set duration ,for the purpose of rotating said rotatable member to release periodically fromV the pockets formed by the'`V j vanes thereon predetermined amounts oi coke into said rebox, an ash pit underneath said grate, Ymean-s for shaking said grate to release ashes therefrom into said ash pit, a conveyor` for removing tashes accumulated in said ash, pit, means for operating said conveyor, and means governed by said motor in variably Vadjustable timed relationtherewith for periodically oper- Y ating said grate-shaking and conveyor-operating means.

9. The structure defined in claim 1, together with variably adjustable timing means for operating said motor periodically in predetermined successive intervals of set duration for the purpose of rotating said rotatable member to release periodically from the pockets formed by the vanes thereon predetermined amounts of coke into said rebox for burning on the grate therein, an ash pit underneath said grate, means for shaking said grate to release ashes therefrom into the ash pit, a conveyor for removing the ashes from said ash pit, means for operating said conveyor, means governed by said motor in variably adjustable timed relation therewith for periodicallyv operating said grate-shaking and conveyor-oper`- ating means, and means for variably adjusting the duration of operation of said grate-shaking and conveyor-operating means.

l0. In a furnace of the class described, wall means deiining a coking chamber, a rotatable feed member disposed in said coking chamber, said feed member having radial vanes forming pockets for receiving coal, a conveyor for supplying coal for deposit in the pockets of said feed member, wall means defining a chamber forming a nrebox provided with a grate disposed underneath said coking chamber, the heat radiating upwardly from said firebox being utilized for the conversion of the coal in the pockets of the rotatable member to form coke, a motor for cone trolling the operation of said rotatable member, variably adjustable timing means .for periodically operating said motor for successive intervals of set duration, whereby said rotatable member is rotated by predetermined angular amounts to dispose said pockets angularly so as to release amounts of coke successively into said rebox for burning on the grate therein, and means governed by said motor for actuating the coal supply conveyor for like intervals of operation, whereby amounts of coal are supplied to the pockets of said rotatable member for coklng therein which correspond substantially to the amounts of coke removed therefrom for burning on the grate in said rebox.

11. The structure and operation defined in claim l0, together with wall means forming with the wall means dening said rebox a combustion chamber disposed adjacent to but separated from said nrebox, partition means in said coking chamber forming with a wall of the means forming such coking chamber a passage for conducting downwardly gases which move upwardly from the coking chamber, one of the wall means of said firebox having ducts formed therein for receiving the combustible gases formed in the coking of the coal in said coking chamber and conducted through said passage and the combustible gases produced in the burning of the coke on said grate for conducting the intermixed gases into said combustion chamber for combustion'therein at a temperature exceeding that which obtains in said coking chamber and in said rebox.

12. In a furnace of the class described, wall means forming a coking chamber, a rotatable feed member in said coking chamber having radial vanes forming pockets for receiving coal, a conveyor for supplying coal to said pockets, wall means forming a rebox provided with a grate disposed underneath said coking chamber, the heat radiating upwardly from said rebox being utilized for the conversion of the coal in the pockets of the rotatable member to form coke to be burned on the grate in said rebox, a motor for controlling the operation of said rotatable member, variably adjustable timing means for periodically operating said motor for successive intervals of set duration, whereby said rotatable member is rotated by predetermined angular amounts to cause release of predetermined amounts of coke successively from the pockets thereof into the rebox, means governed by said motor for actuating said coal supply conveyor for like intervals of operation, whereby amounts of coal are supplied to the pockets of said rotatable member for coking therein, which amounts correspond substantially to the amounts of coke removed therefrom for burning on the grate `in said iirebox, a `device for regulating the air supply to said flrebox, said device comprising a valve disposed in a gas exhaust duct, contro-l means for normally maintaining said valve in a position wherein the air supply is relatively throttled, and means governed by said timing means for operating said control means to increase the air supply to said rebox during and slightly after the periods of operation of said motor.

13. In a furnace of the class described, means forming a coking chamber, a rotatable feed mem'- ber disposed in said coking chamber having radial vanes forming pockets for receiving coal, a conveyor for supplying coal to said pockets, means forming a iirebox provided with a grate disposed underneath said coking chamber, the heat radiating upwardly from said rebox being utilized for the conversion of the coal in the pockg ets of the rotatable member to form coke to be burned on the grate in said fireboX, .a motor for controlling the operation of said rotatable member, a normally operative variably adjustable timing means for periodically operating said motor for successive intervals of set duration, whereby said rotatable member is rotated by predetermined angular amounts to cause release of predetermined amounts of coke successively from the pockets thereof into said rebox, means governed by said motor for operating said coal supply conveyor for like intervals of operation, whereby amounts of coal are supplied to the pockets of said rotatable member for coking therein which correspond substantially to the amounts of coke removed therefrom for burning on the grate in said rebox, a control device for governing the operation of said motor in accordance with heat conditions produced by said furnace, said control device comprising switching means for disconnecting said normally operative timing means, and additional timing means coacting with said control device for thereafter governing the periodic operation of said motor in accordance with intervals of different duration.

14. In a furnace of the class described, means forming a coking chamber, e, rotatable feed member disposed in said coking chamber and having radial vanes forming pockets for receiving solid fuel, a conveyor for supplying coal to said pockets, means forming a rebox provided with a grate disposed underneath said coking chamber, the heat radiating upwardly from said flrebox being utilized for the conversion of the coal in the pockets of the rotatable member to form coke to be burned on the grate in said firebox, a motor for controlling the operation of said rotatable member, variably adjustable timing means for periodically operating said motor for successive 15 intervals of set duration, whereby said rotatable member is rotated by; predetermined angular amounts to cause release of predetermined amounts of coke successively from the pockets thereof intothegfirebox, means governed by said motor for actuating said coal supply conveyor for like intervals of operation, whereby amounts of coal are supplied to the pockets of said rotatable member for coking therein which correspond substantially to the amounts of coke removed therefrom for burning on the grate in said rebox, a device for controlling the disposal of ashes from the, furnace, variably adjustable timing means governed by said motor for periodically operating said'device in timed relation with the operation of said motor, and means for variably adjusting the .duration of operation of said ash disposal device; y

15. In a furnace of the class described, wall means forming a coking chamber, a supply device in said coking chamber, said supply device comprising a pair f rotatable membersv disposed in parallel and extending transversely across said coking chamber each member carrying a plurality of radial vanes forming sector-like pockets thereon, means for periodically downwardly feeding to said supply device a predetermined amount of coal for deposit in the pockets of said rotatable mem-bers which are at'the time of such feeding upwardly directed, wall means forming a re- Y boxgprovided with a grate disposed underneath Y said coking chamber, the heat radiating upwardiirebox into said combustion chamber foi` substantially complete combustion therein.

'17. 'In a furnace having a firebox provided with a grate for. burning solid fuel, apparatus for governin'gY the Ioperation of said furnace, said apparatusY comprising a timing device, means governed by said timing 4device for automatically periodically supplying predetermined amounts of fuel to said grate, damper means for regulating the draft through said iirebox, control means governed by said timing device for automatically operating said damper means, said control means comprising a motor for rotating a cam and for simultaneously actuating said damper means, and means governed by said ca m for governing the operation of said motorto cause opening of said damper Ameans to furnish an increased draft through said firebcx for and slightly after the duration of periods of feeding the fuel to the grate and for thereafter returning said damper tonor- Y malsoas to furnish a decreased draft through the furnace for periods when no fuel is fed to the grate.

1`8.-In a furnace of the class described having wal-l means defining a chamber-forming a iirebox provided with a grate for burning solid fuel, a device for feeding `fuel to said grate, said device comprising a pair of rotatable members positioned side by side and extending in parallel relation transversely across the chamber above the grate in said rebox, each rotatable Vmember having a thereby rotating other pockets angularly upwardly to position them for receiving fuel supplied b said delivery means.

19. The structure and combination defined in claim 18, together with a row of pivotally mounted downwardly depending movable shields disposed above each rotatable member, said rows of shields forming a laterally yieldable downwardly directed passage for directingthe periodically supplied amounts of fuel downwardly from deposit in the pockets of said members.

20. In a furnace havin-g a iirebox for burning solid fuel and equipped with supply means forl supplying fuel to said firebox, apparatus for governing the operation of said supply means, said apparatus comprising a normally operative vari-V ably adjustable principal timing device for causing the operation of said Vsupply meanspericdically in predetermined time intervals of set duration for the purpose of periodically feeding predetermined amounts of fuel to said rebox, an auxiliary timing device for operating said suppl-y means periodically in accordance with time in-V tervals of different duration, a thermostat for actuating said auxiliary timing device, and switching means governed by said thermostat for disconnecting said principal timing device when Y the auxiliary timing device becomes effective.Y

2l. In a furnace having a irirebox containing a` grate for burning solid fuel and supply means for feeding such fuel to said grate for burning there- I in and provided with damper means disposed in a gas exhaust duct forrregulating the draft through the iirebox, apparatusfor operatively correlating theactuation of said supply means With the actuation of said damper means, said apparatuscomprising a motor for actuatingsaid supply means, a motor for actuatingsaiddarnper means, and a Variably adjustable timingdeviee vfor actuating said motors periodically for predetermined time intervals of set duration fory periodically supplying predetermined amounts of fuel to said rebox for burning therein -andrfor simultaneously adjusting said damper Ineans,- n

grate-shaking and said ash-removal means,` a variably adjustable timing device for actuatingY the motor of said supply means periodically for time intervals of set duration for the purpose'iof periodically feeding predetermined amountsof fuel to said grate for burning thereon, auxiliary time-controlled means for governing the operation of the motor of said grate-shaking Vand ashremoval means, and means governed by the motor of said supply means foroperating'saidauxiliary Y time-controlled means. toractuate said `f'gnate-shaking and said ash-removal motor for a time period of set duration once for a predetermined plurality of periodic operations of said supply means.

JOI-IN A. KREUSER.

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

UNITED STATES PATENTS Number 18 Name Date Schroeder et al June 27, 1933 Kelly Jan. 30, 1934 Kelly Jan. 30, 1934 Foresman Oct. 16, 1934 Vodoz Dec. 18, 1934 Kohout Feb. 5, 1935 Bressler Apr. 2, 1935 Hunt Aug. 13, 1935 Grine et al. Dec. 3, 1935 Reid, Jr Mar. 23, 1937 Muir et al, May 3, 1938 Macchi May 24, 1938 Hellman et al Oct. 31, 1939 Selig, Jr. Oct. 22, 1940 Bressler Feb. 25, 1941 Tate Dec. 9, 1941 Hallinan July 25, 1944

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