US2099827A - Wet refuse burning grate - Google Patents

Description

Nov. 23, 1937. J. SCHRENK WET REFUSE BURNING GRATE Filed May 25, 1935 2 Sheets-Sheet l INVENTOR LOU/6 J SCH/Pf/VK BY V IIIIIII I ATTORNEY Nov. 23, 1937. L. J. SCHRENK 2,099,827

WET REFUSE BURNING GRATE Filed May 25, 1935 2 Sheets-Sheet 2 Q o 4L 32 i iium ATTORNEY Patented Nov. 23, 1937 UNITED STATES PATENT OFFICE 1 Claim.

This invention relates to a grate, or hearth, for burning wet fuels and, particularly, to such a grate used in conjunction with auxiliary firing as with pulverized fuel.

5 In burning wet fuels, such as garbage, sewage screenings and the like, or mixtures of wet and dry fuels within the furnace of a steam boiler, as is disclosed in my co-pending application, Serial No. 719,637, filed April 9, 1934, I have found that burning is materially improved if the wet fuel is agitated. This application is a continuation in part of said application.

One object of the present invention is to provide in a furnace for burning wet fuels, where combustion is augmented by supplementary fuel, the combination of a fluid-cooled grate and means for agitating the wet fuel, the grate serving to cool and protect the agitating means.

Other objects and advantages of the invention 20 will become apparent upon consideration of the following detailed description and the appended claim when read in conjunction with the accompanying drawings in which:

Figure 1 is a cross-sectional elevation of a boiler and furnace involving the invention.

Figure 2 is a plan View of a portion of the grate;

Figure 3 is an enlarged side elevation partly in section of a portion of the grate and shows the 30 construction and operating means for the fuel agitators in one form thereof;

Figure 4 is a section on line 44 in Figure 3.

Figure 5 is a section on line 55 in Figure As shown in Figure 1, the wet refuse is burned on a fluid-cooled grate If] which is at the bottom of a furnace II. Another or supplementary fuel is burned and directed into the furnace so that its flame may impinge or pass over the surface of the wet fuel to be burned. Such other 40 fuel may be in the form of a pulverized fuel stream which as shown is directed downwardly by burners l2, the flames l3 descending toward the grate I0, and thence bending upwardly in the shape of a U and leaving the furnace at the upper end. The furnace in this case is surmounted by a steam boiler M of a usual type, for absorbing the heat from the gases leaving the furnace.

The grate or hearth l comprises a plurality of spaced tubes extending longitudinally of the furnace, the tubes being connected into headers l6 and I1, and thence through downcomers l8 and risers 20 to the steam and water drum 2| of boiler I4 for circulation of boiler water therethrough. At the end of the grate where the wet fuel enters, the intertube spaces of the grate are covered by blocks or tiles 22, preferably of cast iron, arranged to have air spaces 23, Figure 4. Further down the grate I provide several transverse rows of oscillatable agitators 5 24, and below these the intertube spaces are again covered by similar tiles 22. Compartments 25 may be formed by partitions 26 to divide the air space beneath the grate into zones delivering air at different volumes and pressures through the related sections of the grate.

The wet fuel, in this case garbage or a mixture of garbage and rubbish, enters through the hoppers 21 of a feeding mechanism which, in this case, consists of a multiplicity of reciprocable feeding rams 28, which are arranged in horizontal alignment across the grate. The rate of feed may be varied by the number of strokes the rams make in a given time. From the hoppers 27, the wet fuel falls in front of the feeding rams 28, on their rearward stroke, and is pushed into the furnace H onto the grate H] on the forward stroke of the rams. On the grate the fuel may assume the general shape shown in Figure 1. The flames E3 of the supplementary fuel stream 25 sweep over the wet fuel bed in a direction opposite to that of the wet fuel travel down the grate and the high temperature of these flames supplies the heat for drying and igniting the wet fuels.

I have found that combustion of the wet fuel may be materially improved by providing the agitators 24 which are adapted to be oscillated through an angle of to turn the fuel bed over so that its constituents may be thoroughly and repeatedly exposed to the drying and consuming action of the flames in the furnace. The agitators are, preferably, made of iron or steel in the forms of sectors of a circle and arranged in rows, in this instance three, transversely of the grate.

As shown in Figure 3, the agitators are in the form of quadrants oscillatable about pivot pins 30 carried by cast iron or steel plates 3| supported on and between pairs of grate tubes l5, Figure 5. The plates 3| are formed with slots 32 through which the agitators are oscillatable and which are normally occupied by the apertured radially extending top surfaces 33 of the agitators that support the wet fuel as it passes thereover down the grate. The apertured top surface 33 of each agitator 24 comprises a series of inclined overlapping slats or plates 34 spacedly mounted between sectional side plates 35 of the agitator. The top plates 34 are disposed at a downward angle to the upper radial edge 33 of along the grate. When an agitator is swung into the furnace, the side plates 35, depending below the top plates 34 and an arcuate plate 31 mounted between the plates 35- maintain the slot 32- in plate 3| closed. This results in preventing air being blown into, the furnace through the sides and ends of the agitators and also precludes fuel falling through the latter from adjacent portions of grate i0.

The number of agitators 24 in each transverse row depends on the Width of thefurnace. All of the agitators in .a transverse row may be operated by a pressure cylinder 40, or the agitators of a row may be divided into groups operable by cylinders individual to the respective groups.

Each agitator is connected by a linkage 4| to a' 'rock shaft 42 operable in turn by the piston associated with the cylinder) through a linkage g 43. 'The valves 44 for controlling the operation of the several transverse rows of agitators, or the groups of each row, may be conveniently located, as at the side of the furnace, for manual control. If desiredthe valve control 'members '45 may be mechanically or electrically connected with the operating mechanism of rams 28 for automaticactuation in any desired relation. to the latter. J 7

As the Wet fuel is fed into the furnace it is V exposed to the drying and consuming action of the flames in the furnace as it is advanced along the grate on the introduction of successive charges by the'rams 28. The air jets directed through passages 36 in the agitators not only supply air for combustion but also assist in drying the wet fuel and moving it along the grate. when the agitators 24 are oscillated they act to push the wet fuel downwardly through thegrate'and 'm entary fuel alone would be used. In either case,

the wet fuel grate and the agitators would be subject to-considerable heat, since the protection of the wet fuel is then minimized or may even be .removed. Under such circumstances the fluidcooled tubes of the grate absorb sufficient heat, mostly by'radiation from the agitators, to protect them from burning or warping.

Although an illustrative embodiment of my invention has been shown and described in detail herein, there are many changes and variations thatmay be made without departing from the invention and which I, therefore, desire and intend to include within thescope of the following claim. What I claim is: V

In a refuse burning boiler and furnace installa' tion having'a boiler, acombustionchamber, an inclined perforate hearth in' said chamber, means for feeding refuse to the hearth and means for supplying air under pressure through the hearth and the bed of refuse thereon; a plurality of pivoted agitators. interposed in the hearth and operable to advance the fuel therealong, 'sai d agitators each having fuel contacting surfaces in cluding a plurality of plates disposed horizontally and arranged in overlappedrelation with their adjacent ends spa'ced'to form a 'p'luralit'yof "air passages inclined relatively to the surface of said hearth for directing air flowing through said passages under pressure in such'manner as to assist in moving the fuel along the hearth. r r LOUIS J. SCHRENK.

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