US2029285A - Furnace - Google Patents

Description

Feb. 4, 193 6. J: s. BENNETT 2,029,285

FURNACE Filed Nov. 3, 1932 2 Sheets-Sheet 1 Fly] I 21 as I 16 II H v i} 1 57 R 1 I 1:

w I 6 3a V 1 I I i 7 l 59 z 10 I 2 5 I 2 I 3 72 were for Joseph 5. 5672721955 Patented Feb. 4, 1936 FURNACE Joseph S. Bennett, Mei-ion, Pa., assignor to American Engineering Company, Philadelphia, Pa., a corporation of Pennsylvania Application November 3, 1932, Serial No. 640,959

7 Claims. (01. nil-165) This invention relates to furnaces, and more particularly to devices associated therewith for collecting the cinders and fly ash blown from the fuel bed and conveying them tohoppers where they may be fed to the furnace and burned with other fuel.

During operation of the furnace at considerable quantity of partially consumed fuel is blown from the fuel bed by the draft air. The fuel so removed from the furnace is usually in the form of cinders which contain a high percentage of carbon. The quantity of fuel removed from the furnacein this manner varies directly with the load and it has been found by experiment that under full load conditions as much as fifteen percent of the entire quantity of fuel fed to the furnace may be lost. This loss of fuel obviously increases the cost of operation considerably as well as reduces the overall efficiency of the unit. The emission of cinders and fly ash fromthe stacks of power plants is also objectionable to inhabitants in the neighborhood of such plants.

The principal object of the present invention is to provide means whereby the cinders blown from the furnace by the draft air may be collected and conveyed to the fuel hoppers from which they are fed to the stoker and burned with other fuel, thus reducingthe cost of operation of the furnace as well as increasing the overall of efficiency of the unit.

Another object of the present invention is to provide means for distributing evenly in the fuel hopper the cinders so gathered.

A further object is to collect the cinders and fly ash blown from the furnace before reaching the stack, thus eliminating to a certain extent the objectionable foreign matter emitted from the stacks of power'plants.

Other and further objects will become apparent as the description of the invention progresses.

0f the drawings:

Fig. 1 is a sectional elevational view taken I through the furnace showing the arrangement of the various elements contained therein including the cinder and fly ash collecting and I tion.

conveying substantially on line 2-2 means comprising the present invenconstruction showing the cinder spout connected directly to the coal spout.

Referring to the drawings, the numeral l designates generally a boiler furnace which comprises a boiler 2, flred by a multiple retort underfeed stoker 3. Fuel from the coal bunker 4 gravitates to the hoppers 5 of the stoker 3 through the usual spouts 6 and l. The hoppers 5 communicate with ram cylinders 8 of the stoker, and the rams 9 reciprocating therein feed predetermined quantities of fuel to the stoker at each reciprocation thereof. Any suitable power mechanism l0 may be employed for operating the rams 9. Draft air is supplied to the furnace by means of a fan II, and the air drawn through fan II is conducted to a preheater l2 through a duct l3, and the heated air discharging from the preheater is conducted to the plenum chamber I4 beneath the stoker 3 through a duct I5. An induced draft fan I6 draws the gases from the furnace in the direction of the arrows around baflies ll, 18 and IQ of the boiler 2. These gases then pass through the preheater l2, fan l6, duct 20, and into the stack 2| of the plant. During the operation of the furnace a considerable quantity of unconsumed fuel is blown from the fur- 'nace by the force of the draft air and if no means were provided to collect this matter a considerable portion thereof would be carried out through the stack. A certain quantity of this material would also lodge in various of the passages and thus impair proper operation of the furnace and boiler unless removed at frequent intervals. In order to prevent the loss of fuel carriedfrom the furnace inthis manner, and to eliminate the gathering of such material in undesirable places, I'have devised the following mechanism.

Referring to Fig. 1, it will be seen that the baffle I1 is spaced from the lower drum 22 of the boiler 2. A certain quantity of the cinders and fly ash may thus gravitate between the portion of the tubes 23 of the boiler 2, and the tubes 24 of the rear water wall 25 extending between baffle l1 and drum 22, and into a hopper 26. The remainder of the cinders and fly ash are carried by the gases to the preheater l2 and are trapped as the gases passthrough a trap 21 provided at the lower end of said preheater. Trap 2'! communicates with a second hopper 23 positioned adjacent to hopper 2B. The lower ends of hoppers 26 and 28 communicate with spouts 29 and 30, respectively, which in turn communicate with a blower 3|. Valves 32 and 33 are provided in spouts 29 and 30, respectively, so that the dis- 23 and 23 into the blower 3| may be controlled. The valves 32 and 33 may be'of any suitable type, such, for example, as the star or screw feeder type of valves which permit the passage of cinders from the hoppers to the blower but prevent the passage of gases therethrough. A duct 34 leads from'blower 3| to a trap 35 positioned some dlistance above the boiler 2. The air utilized in forcing the cinders and fly ash from the blower 3| to the trap 35 discharges through a duct 33 connecting said trap with the duct 23. Trap 35 communicates with a hopper 31 which in turn com municates with a downwardly extending spout 33.

tion, the opening at the bottom of compartment 43 is first uncovered causing the cinders to gravitate into the rearward end of cylinder 8, and as the ram continues its forward movement the coal from compartment 42 fills the remaining space of cylinder 3 evacuated by the ram. As the ram moves-rearwardly the coal and cinders are fed to the stoker. During this feeding -operation the coal and cinders are compressed and as they leave the cylinder 8 the coal is forced over the cinders as shown in Fig. 3. Thus the cinders are held down by the coal and will not be blown from the furnace by the draft air. Inasmuch as the cinders are light in weight, and thus could readily be carried from the fuel bed by the air, it is important that they be fed to the stoker in the manner shown herein and be covered by the heavier particles of coal.

In order to distribute the cinders evenly in the hoppers so that a uniform amount of cinders 'and coal will be fed to each of the retorts of the stoker the following mechanism'is provided.

' Referring to Fig. 2, it is seen that spout 39 has secured near the upper end thereof a bracket 44 having a' laterally extending stud 45 secured thereto. One end of a link 46 is pivotally attached to stud 45, the other end being pivoted to a crank pin 41 provided on a disc 48. Upon rotation of disc 48 it is seen that spout 39 will oscillate between the positions shown indotted lines in Fig. 2, thereby distributing the cinders evenly in the hopper 5. Any suitable means may be provided for rotating disc 48.

Other mechanisms obviously may also be employed to distribute the cinders in the hoppers 5. For example, the spout 38 may be extended and connected directly to the coal spout i as shown in Fig. 4. By this construction the coal and cinders"- would be mixed before entering the hoppers 5.

From the foregoing description, it is seen that a highly useful means has been provided, and

- ducted in said fuel hopper,

I v a',oao,ass charge of cinders and ash from the hoppers obvious, however, that other types of stokers and boilers may be employed without departing from the invention. Insteadof employing a blower for conducting the cinders and fly ash from the hoppers positioned adjacent the boiler and preheater,

other forms of conveyers, such, for example, as the bucket and belt types of conveyers may also be employed. Some of the elements of the mechanism shown herein may also be arranged-in a different manner to better adapt it for use in other types of furnaces.

It therefore is to be understood that it is not intended to limit the invention to the one embodiment herein shown, since it may be embodied in other forms, all coming within the scope of claims which follow.

What is claimed is:

1. In a deviceof the class described, the combination with a fuel burning furnace, of a fuel hopper, a boiler provided in said furnace, baiiles provided on said boiler forming passages through which the gases in said furnace are circulated, cinder and fly ash collecting means associated with said baflies, means for conducting the cinders and fly ash so collected to a hopper, an oscillatory spout associated with said hopper, and means for oscillating said spout. to evenly distribute the cinders and fly ash so conducted in the fuel hopper.

2. In a device of the class described. the combination of a furnace, a boiler provided in said furnace, a preheater, hoppers provided adjacent said boiler and preheater into which the cinders and fly ash blown from the furnace are collected, a fuel hopper, means for conducting the cinders and fly ash from said hoppers first named to said fuel hopper, and oscillatory means for evenly distributing the cinders and fly ash so con- 3. In a furnace, the combination with a boiler, of a stoker positioned beneath said boiler and having a fuel hopper, a series of baflles provided 'on said boiler for circulating the gases passing therethrough, a hopper disposed beneath certain of said bailies for receiving cinders and fly ash blown from said stoker, a passage formed by other of said baiiles, a preheater communicatingwith said last mentioned passage, a trap provided in said preheater for preventing the passage therethrough of cinders and fly ash, a hopper communicating with said trap, a second trap, means for conducting the cinders and fly ash collected in said hoppers communicating with said baiiles and firstmentioned trap to said last mentioned trap, a hopper communicating with said last mentioned trap, aspout communicating with said hopper, a second spout communicating with said first named spout, and means for. oscillating municating with said hopper having a ram operating therein, partition means provided in said hopper dividing said hopper into compartments,-

means for supplying coal to one of said compartr ments and cinders to another of said tempera" ments, and means for operating said mm to feed the coal and cinders gravitating into said cylinder to said stoker at each reciprocation of said ram.

5. In a furnace, the combination with a stoker,

of a fuel hopper forsaid stoker, fuel feeding.

means communicating with said hopper, partition means in said hopper dividing said hopper into separate compartments, means for supplying coal to one of said compartments and cinders to another of said compartments, and means for operating said fuel feeding means to feed said coal and cinders to said stoker.

6. In a furnace, the combination with a stoker, of a fuel hopper for said stoker, a cylinder communicating with said hopper, a ram operating in said cylinder, partition means in said hopper forming compartments therein, means for depositing coal in one of said compartments and cinders in another of said compartments, said compartments being so arranged that the cinders will first enter said cylinder upon recession of said ram and coal will thereafter enter said cylinder, and means for operatingsaid ram to feed said cinders and coal to the stoker in such a manner that a portion-of the coalwili overlie said cinders.

7. In a furnace, the combination with a multiple retort underteed stoker, of a cylinder for each of said retorts having a ram operating therein, a fuel hopper communicating with said cylinders, partition means in saidhopper forming compartments therein, means for supplying coal to one of said compartments, means for supply ing cinders to another of said compartments, said compartments being so arranged that upon recession of said rams the cinders will first enter said cylinders and coal will thereafter completely 1 fill said cylinder, means for actuating said rams to feed the cinders and coal to'the retorts of said stoker, in such a manner that a portion 01' the coal will overlie the cinders, and means for evenly distributing the cinders in said hopper so that a 15 uniform quantity of cinders and coal will be fed to each retort of said stoker.

JOSEPH S. BENNETT.

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