US2431422A

US2431422A - Air feeding furnace front structure

Info

Publication number: US2431422A
Application number: US547705A
Authority: US
Inventors: Gustav A Rehm
Original assignee: Riley Power Inc
Current assignee: Riley Power Inc
Priority date: 1944-08-02
Filing date: 1944-08-02
Publication date: 1947-11-25
Anticipated expiration: 1964-11-25

Description

Nov. 25, 1947. G. A; REHM AIR FEEDING FURNACE FRONT STRUTURE Filed A 2, 1944 GUSTAV A. REHM Patented Nov. 25, 1947 UNITED STATES PATENT OFFICE AIR' FEEDING' FURNACE FRONT STRUCTURE Gustav A. Rehm, Worcester, Mass., assignor to Riley Stoker Corporation, Worcester, Mass., a corporation of Massachusetts Application August 2,1944, Serial No. 547,'705

6 Clams. 1

This invention relates to furnaces, and more particularly to the Construction of furnaces of the type having an upright wall provided with openings through which fuel is introduced for combustion within the furnace.

In one commonly used furnace Construction, the front wall of the furnace is provided with a plurality of horizontally spaced openings through which fuel is projected rearwardly by mechanical feeders knows as "spreader stokers. The fine particles of fuel burn in suspension, while the coarse particles fall upon a grate. Upright piers of refractory material serve to separate the openings. These piers are exposed to radiant heat from both sides as well as from the rear, and their useful life under these Operating conditions is very short. Further dificulties are encountered through failure of the fine particles to ignite promptly, many such particles being carried out of the combustion chamber in an unburned condition by the action of the furnace gases.

It is accordingly one object of the invention to provide a furnace Construction which will Withstand severe Operating conditions throughout a long life of useful service.

It is a further object of the invention to provide a new and advantageous Construction for the refractory piers between the fuel inlet openings of a furnace, whereby the life of such piers will be greatly prolonged.

It is a further object of the invention to provide an improved Construction of furnace for use with spreader stokers, whereby a more efiicient combustion of the fuel may be obtained.

With these and other objects in view, as will be apparent to those skilled in the art, the invention resides in the combination of parts set forth in the specification and covered by the claims appended hereto.

Referring to the drawings illustrating one embodiment of the invention, and in which like reference numerals indicate like parts,

Fig. 1 is a horizontal section through the front portion of a furnace, the section being taken on the line l of Fig. 2;

Fig. 2 is a section on the line 2-2 of Fig. 1;

Fig. 3 is a section on the line 3-3 of Fig. 1;

Fig. 4 is a perspective View of a refractory block; and

Fig. 5 is a fragmentary View of a slightly modified Construction.

The embodiment illustrated comprises a furnace having two upright side walls ID, a front wall Il, a grate !2, and a dead plate I i in front of the grate. The front wall ll is of the wellknown structurally supported type, and its lower edge ,is spaced above the level of the grate and dead plate. This space between the dead plate !4 and the lower edge of the wall ll thereabove is divided into a plurality of openings !5 by means of upright refractory piers !6. An upright vertical metal front plate [8 is mounted at the front of the furnace and forms a support for spreader sto-ker mechanisms |9 which serve to project fuel rearwardly through the openings !5. These mechanisms !9 are of any suitable and well-known Construction, and as shown each mechanism comprises a, hopper 2! from which fuel descends by gravity to a reciprocable ram 22, this ram feeding the fuel at a controlled rate to a rotating reel 23 which projects the fuel rearwardly. The front plate s is provided with doors 25 located directly beneath the stok-er mechanisms !9 to afford access to the fuel bed, and With doors 26 which afford access to the ash pit or air chamber 2'! beneath the grate |2.

The piers !6 are of hollow Construction, and provision is made for circulating air through the interier of the piers and then discharging this air into the furnace to aid ethe combustion of the fuel. Preferably each pier includes a series of superimposed refractory blocks 29, with the lowermost block supported on the dead plate Il. Each block 29 is V-shaped or bifurcated in plan, and the two branches of the V extend toward the front and into contact with the front plate !8 to provide a vertical passage for the flow of air. This passage is closed at the top by a special block 30 of the same external shape as the blocks 29 but without an internal opening. The space between the top block 30 and the lower edge of the front wall ll is filled with plastic refractory material 3l. A vertical flanged metal bar 33 of I cross section is located within each pier 16 and suitably fastened to the front plate, and each block 29 is provided with a pair of opposed inwardly extending lugs 34 which engage the fianges of the bar to anchor the blocks in place. Each block 29 is also provided on both its upper and its lower surfaces with a pair of grooves 35 which diverge in a rearward direction, these grooves forming channels for the flow of air from the interior of the piers to the furnace.

A'r is supplied to the interiors of the piers !G either by forced draft or by natural draft. In the event the furnace is operated with forced draft, the air chamber 21 will be supplied with air under pressure from a suitable fan, and some of this air may be admitted to the lower ends of the piers IS through pipes 31 leading through the dead plate I 4 and provided with valves 38. As shown on F'g. l, two of these pipes may be provided for each pier, on opposite sides of the anchor bar 33. In the event the furnace is operated with natural draft, small doors 40 may be provided in the front plate !8 to admit air to the intero' of each pier 16 on opposite sides of the anchor bar 33.

In Fig, 5 a slightly modified Construction is shown, each of the refractory blocks in the pier !6 being formed of three interftting pieces, namely a rear nose piece 42 and two wing pieces 43. Vertical ribs 45 may be provided on the front plate [8 to aid in retaining the wing pieces 43. The lugs 34 and air channels 35 are formed on the nose piece 42.

The operation of the invention will now be apparent from the above disclosure. The hoppers 2l are filled with fuel, which preferably has been crushed, and the rams 22 feed the fuel at a controlled rate to the rotating reels 23, which project the fuel rearwardly through the openings I5. The fine particles of fuel burn in suspension, while the larger particles are deposited on the grate l2 and form a bed of burning fuel. Air enters the piers IS, either by natural draft through the doors 40 or by forced draft through the pipes 31, and fiows upwardly through the piers in cooling relation to the refractory blocks 29. This air escapes into the furnace through the channels 35, and because of the proximity of the air jets to the entering fuel stream they are of great assistance in maintaining ignition of the fine fuel particles. Accordingly these particles burn in suspension, as desired, instead of being carried out of the furnace is an unconsumed form by the furnace gases. The air cooling of the blocks 29 is so effective that they will remain in proper Operating condition throughout a. long life of useful service. The bars 33 serve to anchor the blocks firmly in their proper positions.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

1. A furnace comprising a grate, walls defining a combustion chamber and including a front wall with it lower edge spaced above the grate, the grate being located within the combustion chamber, an upright pier of rearwardly converging cross section dividing the space beneath the wall into two openings through which fuel may be admitted to the urnace, the pier having a vertical passage therein and vertical rows of channels leading laterally from the passage to the adjacent openings, and means to circulate air through the passage and thence through the said channels 2. A furnace comprising a grate, walls defining a combustion chamber and including a front wall with its lower edge spaced above the grate, the grate being located within the combustion chamber, two laterally spaced upright piers beneath the said wall and forming the sides of a rearwardly and laterally flaring opening, a spreader stoker mechanism arranged to project fuel rearwardly through the said opening to the grate, each pier having a vertical passage therein and a vertical row of channels leading laterally from the passage to the said opening, and means to circulate air through the passage and thence through the said channels. i

3. A furnace comprising a grate, walls defining a combustion chamber and including a front wall with its lower edge spaced above the grate, the grate being located within the combustion chamber, a series of superimposed refractory blocks of rearwardly converging shape in plan forming an upright pier dividing the space beneath the front wall into two openings, spreader stoker mechanisms arranged to project fuel rearwardly through the said openings to the grate, the blocks being of hollow Construction to provide a, vertical passage within the pier and channels leading laterally from the passage to the said openings, and means to supply air to the passage for discharge from the said channels and mixture with the fuel particles traveling through the openings.

4. A furnace comprising a grate, walls defining a combustion chamber and including a front wall with its lower edge spaced above the grate, the grate being located within the combustion chamber, an upright metal plate at the front of the furnace, a series of superimposed refractory blocks forming an upright pier dividing the space beneath the wall into two openings through which fuel may. be admitted rearwardly into the furnace, each block being of bifurcated shape in plan with the two branches thereof engaging the rear surface of the said plate to provide a vertical passage within the pier, and means to circulate air through the said passage.

5. A furnace comprising a grate, walls defining a combustion chamber and including a front wall with its lower edge spaced above the grate, the grate being located within the combustion chamber, an upright metal plate at the front of the furnace, a series of superimposed refractory blocks forming an upright pier dividing the space beneath the wall into two openings through which fuel may be admitted rearwardly into the furnace, each block being of bifurcated shape in plan with the two branches thereof engaging the rear surface of the said plate to provide a, vertical passage within the pier, a vertical flanged metal bar located within the passage and secured to the said late, lugs on the blocks engaging the bar to hold the blocks in position, and means to circulate air through the said passage.

6. A furnace comprising a grate,`walls defining a combustion chamber and including a, front wall with its lower edge spaced above the grate, the grate being located within the combustion chamber, an upright metal plate at the front of the furnace, a series of superimposed refractory blocks forming an upright pier dividing the space beneath the wall into two openings through which fuel may be admitted rearwardly into the furnace, each block being V -shaped in plan with the two branches thereof engaging the rear surface of the said plate to provide a vertical passage within the pier, the blocks having grooves therein forming channels leading laterally from the said passage to the said openings, and means to circulate air through the passage and thence through the said channels.

GUSTAV A. REHM.

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

UNITED STATES PATENTS Number Name Date 1,529, 83 Howren Mar. 10, 1925 1,693,400 Nygaard Nov. 27, 1928 896,440 DeBall Aug. 18, 1908 326,547 Collis Sept. 22, 1885 47,049 Stewart Mar. 28, 1865 459,892 Weir Sept. 22, 1891 613,'785 Sieben Nov. 8, 1898 1,789,223 Drake et al. Jan. 13, 1931 1,360,250 Priebe Nov 23, 1920 1,604,648 Lundgren Oct. 26, 1926 1,944,948 v Preston 1 Jan. 30, 1934