US643820A - Decomposed-steam furnace. - Google Patents

Description

uh. 643,820. Patented Feh.v20 I900. E. n. HODGE & L. H. BABE.

DECOMPOSED ST EAM FURNACE.

(Application filed. June 16, 1899.)

(No Model.) 2 Sheets-Sheet l,

@ mm {ya/P4 @SZQW No. 643,820. Patented Feb. 20, I900.

E. D. HOME 8:. L. H. BABE.

DECOMPOSED STEAM FURNACE.

(Application filed Jurie 16, 1899.) v t (No Model.) Z-Sheets-Sheet 2,

v. c. rns'nonms PETERS 00.. Pno-mm'no WASHINGTON,

UNITED STATES PATENT OFFICE.

ELVA D. HODGE AND LAWRENCE H. BABE, OF CINCINNATI, OHIO, ASSIGNORS TO ALOIS ZECKENDORF.

DECOMPOSED-STEAM FURNACE.

SPECIFICATION forming part of Letters Patent No. 643,820,

dated February 20, 1900.

Application filed June 16,1899. Serial No. 720,825. No model.)

To all wiwm it may concern.-

Be it known that we, ELvA D. HODGE and LAWRENCE H. BABE, residing at Cincinnati, in the county of Hamilton and State of Ohio, have invented certain new and useful Improvements in Decomposed-Steam Furnaces, of which the following is a specification.

The object of our invention is to provide efficient means for burning coal in boiler-furnaces, so as to produce complete combustion, and to prevent the escape of unconsumed gases ofi through the uptake.

In burning bituminous coal in ordinary furnaces a large amount of unconsum ed gases passes up the chimney, which condenses and forms smoke and soot. There are two principal causes for this formation of smoke in furnaces. The first is that the gases are driven off too rapidly without being with the oxygen of the air. The second cause is that air is supplied to the coal and combustible gas at too low a degree of heat.

We obtain approximately perfect combustion in our furnaces by supplying highlyheated oxygen to support combustion and superheated steam supplied right at the point of combustion, which is maintained continuously at a high enough heat to readily decompose the superheated steam on the fuel-bed, which becomes nascent hydrogen and heated oxygen, which gases in their heated condition rapidly unite with the carbonaceous matter of the fuel and produce approximately a thorough combustion of all the gases.

Our appliance is so constructed that a large amount of superheated steam is admitted around the furnace directly upon the fuel,

which decomposes to support combustion and blast to supply at the same time serves as a highly-heated atmospheric air.

The features of our invention are more fully set forth in the description of the accompanying drawings, forming a part of this specification, in which- Figure 1 is a side elevation of our improvement, partly in section, applied to an ordinary boiler. Fig. 2 is a sectional plan View on line 00 m, Fig. 1. Fig. 3 is a sectional elevation of one member of the superheating steam-coil before it is applied to the furnace. Fig. 4. is

a sectional'plan view of the combined steam properly mixed and air supply pipes. line .2 2, Fig. 1. p

A represents the base of the furnace; B, the boiler; O, the bridge-wall; P, the fire-chamber; D, the secondary combustion-chamber; E, the feed-door; F, the ash-pit door; G, the ash-pit; H, the grate-bars. These parts are of ordinary construction.

The gases for supporting the combustion are supplied through a combined steam and air pipe. We preferably employ three limbs or branches of pipe. The large pipe ais laid in the bridge-wall just in rear of the gratebar. The ends of this pipe are united to similar pipe-limbs b b, which are projected, preferably, just inside of the side fire-walls of the furnace. Within the larger pipes are proj ected small steam-pipes c. The outside pipes are provided with aseries of downwardly-inclined nozzles d, through which the gases are injected angularly onto the fuel. The steampipes c are provided with similarly downwardly inclined ejector-nozzles c, which are concentric withthe nozzlesdthroughwhichsuperheated steam is injected, which also serves as a blast to draw in the air supplied through the larger pipes. These orifices are arranged to direct the superheated steam from each side down upon the top of the incandescent-fuel bed, preferably at an angle of about thirty degrees. The steam is decomposed by contact with the said incandescent-fuel bed into nascent hydrogen and oxygen and just at the point that the carbon of the fuel is vaporized, so these nascent gases enter into chemical unions, forming, as near as can be determined, carbon monoxid and marsh-gas,which are perfect fuel gases, the surplus oxygen supporting an animated combustion and the gases being Fig. 5 is a section on consumed as fast as generated. The superheated-air coil insures a supply of superheated oxygen great enough to maintain the high degree of combustion which is to be maintained.

The use of superheated steam with furnaces is well known; but hitherto it has been attempted to blast it in under the grate-bar, which is practically valueless. If it were simply injected into the furnace sidewise, it would oommingle with the products of combustion, but be carried off therewith without ejector-nozzles, as before described.

either decomposition or chemical union. The important point is to decompose it upon the bed of incandescent fuel. Then it must be introduced at such a point as to travel in as short a line as possible, as it adds to the force and insures contact with the top of the fuelbed.

It is desirable to supply atmospheric air highly heated. For this purpose we provide coils of pipe K, which are suspended in the combustion-chamber in rear of the bridgewall and around which the flame and gases freely play, thereby heating the pipes and the air therein. The pipes at their rear end project through the furnace and are provided with dampers 7a to regulate the admission of atmospheric air into the pipes. The forward end of this coil or coils connect with and form a supply for pipes a, which in turn supplies the limbs 12 b.

L represents a superheating steam-coil arranged along and preferably just within the line of the fire-wall on opposite sides of the furnace. The preferred form of arranging this coil is to place a series of return-pipes just inside the fire-walls at the sides of and extending nearly the whole length of the grate-bars. These two coils are supplied by the steam-pipes ff. Within the terminal limbs of the air-pipes the lower ends a of the steam-supply pipes are placed, having the These steam-coils L are connected together by pipef.

In order to obtain any material benefit by the injection of steam to a caloric atmosphere, the steam must be decomposed upon the incandescent bed of fuel. As the steam does not decompose until it reaches a heat approximating from 1,400 to 1,600 Fahrenheit, it is essential to maintain a very high heat in the combustion-chamber and to superheat the stean1,s0 as to prevent the undue cooling of the gases of the fire by the injection of the steam and to maintain the temperature of the upper fuellayerhigh enoughto decompose thesuperheated steam impinged thereon. This we accomplish bya large superheating steam-coil. It is just as necessary to furnish oxygen in a heated condition in order to prevent the cooling of the combustible gases and to properly support the combustion. This we preferably accomplish by the large superheating steam and air coils.

lVe have shown the air-coil made of two sections, tapping the furnace-supply pipe at two points. The same thing could be accomplished by having the same number of feet of pipe formed of one coil and tapping the furnace-supply pipe at one place instead of two.

lVe have shown in Fig. 2 the furnace-supply pipes laid justinside of thefurnace-walls and partially covered by the Wall. The only purpose of embedding the pipes wholly or partially within the wall is to prevent the flame from impinging directly upon the pipe,

and thereby causing it to deteriorate more rapidly. It takes more feet of pipe-coil to obtain the proper amount of superheated steam when the pipes arethus embedded in the wall, and we prefer it simply because it is more durable.

While the air-coil is of great value, good results could be obtained by the use of the steam-coil alone, using a sufficient quantity of steam to supply oxygen to energetically support combustion; also, while the disposi tion of the coils upon each side of the furnace makes the most economical and eflicient distribution of parts, giving the best utility of the steam, a single coil introducing into one side of the combustion-chamber at an angle upon the fuel-bed could be employed with less desirable results.

Mode of operation: The fireis kindled on the grate-bars in the usual manner. Combustion is supported by air admitted through the ash-pit door and up through the gratebars. As soon as the steam is raised in the boiler the apparatus is ready for use. Steam is turned onto the superheating-coils. The air-pipesK being opened,the combined heated air and superheated steam is injected by the nozzles 61 6 down upon the fuel. The force of the steam-blast drawn in the air heated in the pipes K and the maximum amount of air to support the combustion are supplied to these coils in a heated condition. Only a minimum amount of air passes up through the gratebars.

We have found by experience that very sooty bituminous coal can be almost totally consumed in our furnace with no smoke. We have found that the coal is thoroughly consumed without clinkering and that the furnace requires little or no attention except the proper inserting of fuel. We obtain a very high percentage of economy in the amount of fuel used.

It will be observed that the superheating steam-coils on either side of the furnace practically extend the whole length of the firechamber, and they are approximately equal to it in vertical depth of the fire-chamber, thus forming, as it were, a steam-pipe back for the furnace-wall, whereby the radiant heat ordinarily absorbed by the fire-wall is imparted to the pipe, heating it very hot, and the steam passing through the pipe rapidly absorbs this heat. Thus the steam is superheated and raised to a much higher degree thanordinary saturated steam, rendering it much easier to be decomposed than steam applied at an injector without the use of this superheating-coil. We have found by experiment that this superheating of the steam is very essential in order to decompose any large amount of steam, maintaining at the same time a high combustion in the fire-chamber which is not unduly cooled, which would otherwise occur if the steam were not superheated.

The heat taken up by the steam in the superheating-coil is carried back again into the furnace and utilized as the steam is decomposed to support combustion. This is a very important and useful feature of our invention.

Having described our invention,we claim-- 1. In a furnace, the combination of a coil of pipe disposed in the secondary combustionchamber having communication with the air at one end, the said coil having terminal ends disposed within the side walls of the combustion-chamber above the fuel-bed, a coil of pipe having communication with a source of steam-supply vertically disposed in each side wall of the combustion-chamber, a terminal limb from each steamcoil tapping the respective terminal limb of the air-coil and coextensive therewith and concentric dischargeorifices in said steam and air terminal limbs whereby steam and air may be superheated to approximately the gether injected upon the upper surface of the fuel-bed from each side thereof, substantially as specified.

2. In a furnace, the combination of two coils of pipe horizontally disposed in the secondary combustion-chamber having communication same degree and to- 1 with the air through the back thereof each coil being extended forward through the bridge-wall and terminating within the front ends of the said walls of the combustionchamber above the fuel-bed, a branch pipe located in the bridge-wall connecting said pipes, steam-coils vertically disposed in the side walls of the combustion-chamber communioating with a sourceof steam-supply, the terminal limbs tapping and lying within the respective terminal limbs of the air-coils and concentric orifices of discharge downwardly inclined in said steam and air terminals, whereby the steam and air may be superheated to approximately'the same degree and together injected upon the upper surface of the fuel-bed from each side thereof, substantially as specified.

In testimony whereof we have hereunto set our hands.

ELVA D. HODGE. LAWRENCE I-l. BABE. Witnesses:

OLIVER B. KAISER, ALoIs ZEOKENDORF.

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