US791067A - Process of burning fuel. - Google Patents

Description

No. 791,067. PATENTED MAY 30, 1905.

' J. B. ARCHER.

PROCESS OF BURNING FUEL.

APPLICATION FILED JULY 31. 1903.

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P ATENTED MAY 30, 1905.

J. B. ARCHER. PROCESS OF BURNING FUEL.

APPLICATION FILED JULY 31. 1903.

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No. 791,067. PATENTED' MAY 30, 1905.

J. B. ARCHER.

PROCESS OPBURNING FUEL.

APPLICATION FILED JULY a1. 1903.

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Patented May 30, 1905.

PATENT OFFICE.

JOHN B. ARCHER, OF KENSINGTON, MARYLAND.

PROCESS OF BURNING FUEL.

SPECIFICATION forming part of Letters Patent No. 791,067, dated May 30, 1905.

Application filed July 31, 1903. Serial No. 167,724.

To all whom it may concern.-

Be it known that I, JOHN B. ARCHER, a citizen of the United States, residing at Kensington, in the county of Montgomery and State of Maryland, have invented certain new and useful Improvements in Processes of Burning Fuel, of which the following is a specification.

This process of burning fuel is especially designed to effect the complete combustion of solid fuel, such as bituminous coal, in the furnaces of steamboilers, heating plants, and other apparatus consuming a large amount of fuel.

The process enables the heat units of the fuel to be fully utilized, the products of combustion delivered to the stack being substantially free from unburned gases, smoke, soot, and cinders.

The process involves the delivery of air to the ignited fuel, especially to the gases rising from a bed of coal lying on the grate of a firebox, from different directions and along lines substantially tangent to a circle. The jets of air strike the fuel-gases and set them into rapid rotation, effecting a thorough mixture of the gases and air. The centrifugal action caused by the rotary or cyclonic movement of the mixed gases and air throws anyheavier unburned particles outward against the hot walls of the fire-box, where they are quickly consumed.

The process may be carried out by apparatus of widely-different construction. A furnace which has been found especially useful for the purpose is shown in the accompanying drawings, in which Figure 1 is a vertical longitudinal section on line I I of Fig. 2. Fig. 2 is a horizontal section on line II II of Fig. 1. Fig. 3 is a transverse vertical section on line III III of Fig. 1 looking toward the front of the furnace. Fig. 4 is a detail horizontal section through one side of the fire-box on line IV IV of Fig. 3. Fig. 5 is a plan view, partly in section, of the air-box removed from the furnace; and Figs. 6, 7, 8 are elevations of the front, rear, and side sections of the air-box, respectively.

For the sake of completeness the furnace is here shownas arranged to heat a steamboiler 1 of well-known construction. The process is obviously capable, however, of general use. The furnace shown comprises a rectangular fire-box 2, provided with the usual grate 3, ash-pit 4, doorways for fuel 5, having doors 6, and ash-pit doors 7. A short distance above the grate and embedded in the brick walls of the fire-box is the air-box S. This air-box, as shown in Figs. 5, 6, 7, 8, is for convenience made in several sections of cast iron, steel, or other suitable material. The ends of the sections are flanged and bolted together. The side sections 9 10 are each an integral casting, the section 10 being provided with an air-inlet 11. The front portion of the air-box consists of two separate arched sections 12 13 and the rear portion of two separate sections 14 15. Projecting from the inner walls of the air-box are a number of twyers 16, spaced at about equal distances from each other and arranged in superposed series, the twyers of the upper series being intermediate those of the lower series.

Each of the twyers is arranged to deliver a stream of air in a line substantially tangent to a horizontal central circle 17, as indicated by the dotted lines in Fig. 5, the twyers of the arched sections being slightly inclined downward to effect this result. This arrangement causes the jets of air injected through the twyers to strike the gases rising from the fuel and set them into rapid rotation within the fire-box, effecting a thorough mixture of the gases and air. The centrifugal action caused by the rotary or cyclonic movement .of the mixed gases and air throws any heavier particles such as those of the unburned gases-outward against the hot walls of the fire-box. Bricks or tiles 18, preferably consisting of a mixture of graphite and fire-clay, project inwardly from the side walls of the re-box above the air-box. These projections soon become incandescent when the furnace is in operation and cause any unburned fuel-gases which are thrown into contact with them to be immediately burned. The inner faces of the air-box are protected from the excessive heat by triangular or other tiles 19 of fire-clay or by any other suitable means. Air may be supplied to' the airbox through inlet 11 by means of a valved pi e 20. Hot air may be supplied through a va ved pipe 21, leading from a series of heating-coils 22, arranged beneath the rear portion ofthe boiler 1 in osition to be heated by the outgoing pro ucts of combustion. The sections of the air-box are provided with dampers 23, having handles 24. One of these dampers isshown in position within the air-box in Fig. 5. The dampers enable the volume of air delivered from the various sections to be regulated. It is sometimes desirable in operation to decrease the amount of air injected at the front of the fire-box. The greater quantity of air issuing from the twyers at the rear tends still further to hold the gases within the fire-box until they are completely burned. The cyclonic movement within the fire-box is also so controlled as to prevent the too rapid and direct escape of the gases rising from the fuel over the bridge-wall, the gases being thus held within the fire-box until all the combustible matter is consumed and the heat completely utilized in the generation of steam. The products of combustion escaping to the stack pass off as a light gray vapor containing substantially no smoke, soot;or unburned fuel-gases.

When the doors of the ordinary boiler-furnace are opened to permit charging, the inrush of cold air is so great as to temporarily chill the fire-box and boiler-shell and tubes down to a temperature where the carbon in the gases is deposited as soot, which is afterward swept out by the products of combustion, causing clouds of black smoke to be emitted from the stack. This result is practically overcome by the cyclonic movement within my fire-box. If necessary, the amount of air supplied through the twyers may be so great as to cause a slight plenum within the fire-box, entirely preventing the admission of air through the doors. suflicient air-pressure is maintained in the fire-box when stoking to substantially equal the exterior airressure.

To prevent co d air from striking the boiler or other object to be heated, the fire-clay or tile lining 25 beneath each of the arched sec tions 12- 13 is extended rearwardly over the grate for some distance, providing shelves 26. These shelves act as baffles and cause any air that might enter through the doors to pass into the rotating mixture of gas and air. The shelves are preferablyperforated with numerous small openings 27, through which a sufficient amount of the=hot gases passes to keep the shelves at a high temperature and prevent de osit of soot.

Smal test-pipes 28, such as one-half-inch gas-pipe, extend from each side of the air-box at about the middle along the top of the airbox and out through the furnace-wall at some convenient point, such as the front,

In practice just where they are provided with valves 29. These pipes serve to withdraw portions of air from different sections of the air-box, so that the pressure or temperature of the air within any particular section may be tested by applying a gage or thermometer to the outer end of the corresponding test-pipe. The supply of air from the different sections is then suitably regulated by means of the dampers 23.

The area of the air-inlet 11 should be somewhat greater than the combined areas of all of the twyers, thus keeping the air under the desired pressure within the air-box and maintaining a substantially uniform pressure at each twyer.

I claim- 1. The process of burning solid'fuel, which consists in delivering streams of air into an unobstructed space above a bed of the ignited fuel, the air being introduced from different directions and along lines substantially tangent to a circle, thereby producing a cyclonic movement in the gases rising from the fuel, as set forth. 7

2. The process of burning solid fuel, which consists in passing air up through a bed of the ignited fuel, and simultaneously delivering streams of air into an unobstructed space above the bed of ignited fuel, from different directions and along lines substantially tangent to a circle, thereby producing a cyclonic movement in the gases rising from the fuel and throwing unburned particles outward against the hot walls of the fire-box, as set forth.

3. The process of burning solid fuel lying ona grate, which consists in passing air up through a bed of the ignited fuel, simultaneously forcing air into the gases rising from the fuel, from diflerent directions and along lines substantially tangent to a horizontal circle, and separately regulating the amount of air delivered from different directions to prevent the escape of any unburned gases, as set forth.

4. The process of burning solid fuel, which consists in delivering streams of air from a body of compressed air into an unobstructed space above a bed of the i nited fuel, the air being introduced from different directions- JOHN B. ARCHER.

Witnesses:

EUGENE A. BYRNEs, C. A. NEALE.

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