US1379448A - Furnace - Google Patents

Description

R. W KING.v

` FuRNAcE. APPLICATION FILED NOV. I, I9 I9.

IIIIIII :Pantea Mayu, 19211.

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mw. KING. FuRNAcE. APPLICATION man Nov. i, 1 919. 1,379,448. Patented May 24,1921,

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ROBERT W. KING, 0F TORONTO, ONTARIO, CANADA.

FUR/NACE.

Specification of Letters Patent.

Patented May 2d, 192i.

Application filed November 1, 1919. Serial No. 334,912.

To all whom z' may concern:

Be it known that I, ROBERT W. KING, of the city of Toronto, in the county of York, Province of Ontario, Canada, have invented certain new and useful Improvements in Furnaces, of which the following is a specification.

The object of this invention is to provide improved means for the burning of sub-bituminous or lignite coal or other fuels of a like nature. Y

In ordinary practice when such fuel, especially in its broken condition or slack form, is placed on the surface of other ignited fuel it tends to dampen the same and reduce the temperature of the combustion Y chamber.

The new charge heated from below throws off gas from the surface which passing into the cooled combustion chamber, is not consumed but passes awayV in the form of smoke. In the course of time, as combustion commences below, this escaping gas ignites often with explosive violence and an intense fire is created rapidly exhausting and wasting the fuel. I overcome the above difficulties by burning the fuel in a manner made possible by the improved construction hereinafter fully described and shown.

Briefly the method employed is to burn the fuel as largely as possible by ignition from the upper surface downward and at the front of the furnace until it is largely converted into red hot cinders which are then passed to the rear of the furnace to complete their combustion, partly by surface combustion and partly with the aid of air admitted i'nto the fuel bed. This process requires that the fuel at front of the furnace be supported on a substantially iinperforate fuel supporting surface, that a suitable support for partly consumed fuel be provided at the back of the furnace, that air, preferably warmed, be admitted above the fuel at the back of the furnace and caused to travel forwardly over the fuel, that air be admitted under close regulation into the body of fuel at the back of the furnace and that provision be made for the discharge of ashes from the fuel support at the back of the furnace be provided.

The apparatus I have devised for this purlpsetis ieeinaftr specifically described and 1 us ra ec in e accom aan ino` 0' in which` l y g drawings F lgure l is a vertical longitudinal section of a rectangular furnace constructed in accorda-nce with my invention;

Fig. 2 a front elevation of the same partly 1n section;

Fig. 3 a plan View of the same, partly broken away and partly in section;

Fig. l a front elevation of the rock shaft of the shaker mechanism;

Fig. 5 a detail in side elevation of one of the fixed grate bars applied to a cylindrical furnace;

Fig. 6 a modification of my invention applied to a cylindrical furnace; and

Fig. 7 a cross section on the line a-b in Fig. 6.

In the drawings like numerals of reference indicate corresponding parts in the different figures. t Referring particularly to Figs. l to 5 l is the. wall of the furnace, of any suitable material and construction, 2 the combustion chamber or upper part of the fire pot, and 5% the ashpit. The fuel supporting surface 1s formed in two parts a' and 5. The part 4, or primary fuel supporting surface is located adjacent the fuel door G and the part 5, or secondary surface at the rear of the furnace. The part 4 is substantially imperforate, whereas the part 5 has suitable apertures formed therein through which air from the ashpit may be allowed to pass to help sustain combustion of the fuel lying thereon.

At the top of the combustion chamber over the primary fuel supporting surface is located the smoke outlet 7, preferably as close as possible to the fuel door 6. To provide air for the surface combustion of the fuel and the gases evolved therefrom it is necessary to admit air into the combustion chamber above the fuel. For this purpose I provide flues or air passages 9, preferably so located as to be heated by the heat generated in the furnace. In the preferred arrangement these passages are formed in or on the walls of the furnace as shown. Each air passage has a damper controlled air inlet 11 for the admission of atmospheric air,

v(il) Athat the fuel burns mainly being supplied through the. openings 12v the smoke outlet 7 and also a damper controlled opening 10 located within the ashpit of the furnace. Each air passage is provided with one or more openings 12 leading into the upperV part of the combustion chamber above the fuel level, and also with an opening 13 below the level of the fuel at the back ofy the furnace.

From the above construction it follows from above, air

while the final combustion of theV fuel pushed over to the back of the furnace is effected by air admitted through the openings 13 and by such air as may be admitted into the ashpit to pass through the` secondary fuel support 5.

To properly direct the Aair from the inlets 12 andthe products of combustion ,from the rear of the furnace over the fuel'and on the primary fuel support 4, l provide the downwardly and forwardlyinclined baille 8 secured to the top of the furnace just behind For various reasons it -is desirable to raise the primary fuel support 4 above the second- 7 .e -Preferably the parts overlap as shown lll Figi' l; Mld the secondary fuel support-V ing surface 5 slopes toward the front.

rllhe rear edge 15 of the primary fuel supporting surface is preferably downwardly turned to restrict the opening 14E to the extent experience dictates. A lso to facilitate the feeding of fuel over the secondary fuel supporting surface 5, the forward part 16 of the primary fuel supporting surface il is preferably downwardly inclined from the fire door opening as shown inV 1.

ln starting a'fire in the furnace, it is sometimes desirable to have direct draft from the rear part of the combustion chamber and I therefore provide a damper-controlled outlet 17 overI the secondary fuel supporting surface lilith this openingI tbesmoke pipe 1S communicates, which pipe maybe connected'by the pipe 19 with the smoke outlet 7. i Y

The secondary fuel supporting surface 5 `is' p referably arranged to be shaken. ln

Figs. 1 to 5 1 show a preferable arrangementof the grate for use in rectangular' furnaces. Stationary grate bars 2O are alternated with movable. grate'bars 21. The stationary grate barsare supported on the cross bar 22 adjacent the opening la, while their rear ends are supported on the lower `vsides of the furnace.

flange of a channel bracket 23 secured to the rear wall of the furnace. rlhe movable bars 21 slide freely on the cross bar22,l and at their rear ends are pivotally connected with rock arms 2vformed on or secured to aV rock shaft'25 suitably journaled in the y fr depending rock arm 26 is also formed on or secured to the shaft 25. A shaker lever shaft 27 isjournaled at'the front of the furnace and has formed onor-secured thereto a depending rock arm 28. The rock arms 26 and 28 are pivotally connected at the Aopposite ends of a connecting rod 29. fr suitable shaker lever 30 is connected'in any usual manner to` the outer end of. 'they shaft 27. VflVith this arrangement, the shaking of the grate barsmay be effectedvat the front ofthe furnace as is generally a preferred arrangement, though, of course, any` other arrangement ofthe shakin'g'means may be emploved.v 'f Y lt will be noted that each stationary grate bar has a shoulder 31V formed thereonvbehindthe cross bar 22.' To'remove one of the stationary bars it isnecessary therefore to liftits forward end and then draw it forwardly.A No accidental displacement is however possible. To remove a movable grate bar, it is necessary to rock the'rock shaft 25 fartherthan is necessary for shaking purposes tobringthe rear end of the bar to f such a position thatv itfcanbe lifted from its pivot on therock arms v211, the upper member of the channel casting 23 normally pre- 100 venting such lifting action.'V A .removable pin 32 or other. stop is provided which ordie nai-ily. limits the movement of the shaft 25 byengagementwith the rear side of the dependingrock arm 26. Y

To besteffect a discharge of c'linkers of ashes through the opening 14, the grate bars 20 and 21 are preferablycurved concavely at their uppersurfaces and are provided with ratchet-shaped teeth 33, .the teeth pref- 110 erably decreasing in size'toward the rearward part of each grate bar.

'ln Figs.- Grand 7 l show a modification of my invention as applied to" an ordinary lcylindrical hot water heater. The primary fuel supporting surface Ll is shown substantially horizontal, the sloping part 16 shown in Fig. 1 being omitted. The depending part 15' forming the rear edge of this part of the gratey also extends more nearly vertically. The secondary fuel supporting V surface 5 is shown as formed of a series of rocking bars 34 of ordinary type. These will be arranged to beshaken in yany ordinary manner., V

. Y The rearward smoke outlet is in this case omitted, the products kof combustion all passing up through the forward smoke out-- let 7. The air passages 9 remainvsubstantially the Asame as 1n the other form of-fur- 130 nace showmbut I nd it desirable, tomake them of a semi-segmental formin plan and locate them one at each sidey of the rear portion of they grate, the short end rocking bars commonly employed in this'form of furnace being therefore omitted.

The operation of the furnace can best be understood from the following description of an actual run. ln lighting the furnace, the fire pot was first filled with the fuel up to substantially the level of the lower side of the fuel opening as indicated by dotted lines in the drawings, and a small fire of kindling was started at the rear of the combustion chamber at 8.15 a. m. While all drafts were open, the air for supporting the combustion of the kindling was supplied mainly by the air flues 9 through the openings 12 above the fuel. At 8.22 a. m. the direct damper 17 was closed. By 9.15 a. m. the fire was well ignited and the re was checked about 10.15 a. m. by partly closing the ashpit and air flue dampers. By 11.15 the fire was burning steadily and coal was added at the front of the furnace. Gaswas seen to be burning around the air openings 12. By 12.15 the fuel at the back of the furnace had become red hot and gas from the coal at the front of the furnace was burning freely.

At 3.00 p. m. the fire was still steady and more coal was added. At 4.30 part of the air flues 9 were closed. At 6 p. m. more coal was added and all the auxiliary air ports were opened. The fire picked up quickly7 gas burning at the auxiliary air ports as before. Thereafter the fire was partly checked by closing some of the air ues. At 10 p. m. the fire was banked for the night with coal and the dampers closed.

At 9 a. m., the following morning, the fire was in good condition and picked up quickly when the dampers were opened. By this time it was necessary to get rid of some of the ashes on the rear fuel support and to push the fuel from the front of the furnace to the back, leaving space for fresh fuel at the front, while the hot coals finished their combustion at the rear and maintained a suitable temperature in the combustion chamber for the evolution and ignition of the gases of the green fuel.

In this test it was demonstrated that the admission of air through the auxiliary openings 12 and 18 was absolutely essential for complete combustion; that the admission of air from below through the rear fuel support was non-essential; that the admission of air through the space between the two parts of the grate was not detrimental, and in any case was readily controlled by means of the ashpit damper; that the deflecting plate or baiiie in the combustion chamber satisfactorily served the purpose of causing the air and heated gases from the .rear part of. the furnace to impinge on and thus causer the evolution and combustion of the o'ases ofthe green fuel; that the gases evolved burned quietly and thoroughly and without explosions; that flue gas losses were very low and that the efficiency of heat transfer was high.

llhat l claim as my invention is 1. ln a furnace the combination of an imperforate primary fuel support; a secondary fuel support behind the primary fuel support; means for admitting air into the body of the fuel on the secondary fuel support; means for supplying air above the fuel at the rear of the furnace; and a smoke outlet at the front of the furnace above the primary fuel support.

2. ln a furnace the combination of an imperforate primary fuel support; a secondary fuel support behind the primary fuel support partly underlying said primary fuel support and spaced therefrom to provide an ash discharge; means for supplying air above the fuel alt the rear of the furnace; and a smoke outlet at the front of the furnace above the primary fuel support.

8. ln a furnace the combination of an imperforate primary fuel support; a secondary fuel support behind the primary fuel support; air supply ducts adapted to be heated by conduction from the furnace walls and communicating with the interior of the furnace at the rear part thereof above the secondary fuel support at points both below and above the fuel level; and a smoke outlet at the front of the furnace above the primary fuel support.

4. ln a furnace the combination of fuel supporting means substantially imperfora-te at the front of the furnace; means for admitting air above the fuel supporting means into the body of fuel at the rear of the furnace; means for supplying air above the fuel at the rear of the furnace; a smoke outlet at the front of the furnace; and means for the discharge of ashes from above the rear part of the fuel supporting means.

5. In a furnace the combination of fuel supporting means substantially imperforate at the front of the furnace; means for admitting air above the fuel supporting means into the body of fuel at the rear of the furnace; means for supplying air above the fuel at the rear of the furnace; a smoke outlet at the front of the furnace; means for the discharge of ashes from above the rear part of the fuel supporting means; and a baffle intermediate of the ends of the furnace adapted to direct air and products of combustion down against the fuel at the forward part of the furnace.

6. In a furnace the combination of fuel supporting means substantially imperforate at the front of the furnace; means for ad- .mitting air above the fuel supporting means i into the body of fuel at the rear of the urporting means7` and a baille intermediate of nace; means for supplying air above the the ends of the furnace adapted to direct air .fuel at the rear of the furnace; a smoke and products of combustondownagainst 10 outlet at the front of the furnace; a damper the fuel at the forward part of the furnace.

5 controlled smoke outlet at the rear of `the Signed at Toronto this 15th day of Octo furnace; means for the discharge of ashes ber,1919. from above the rear part of the fuel sup- Y' ROBERT W. KING.

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