US1450201A - Means for insuring complete combustion of coal in heating boilers - Google Patents

Description

Apr. 3, 1923, 1,450,201 R. W. BURCKHARDT MEANS FOR INSURING COMPLETE COMBUSTION OF COAL IN HEATING BOILERS.

Filed Aug. 10, 1920 I Invehtan Patented Apr. 3, 1923.

urr sraas RODOLPHE WILLIAM BURCKHARDT, OF MULHOUSE, FRANCE.

MEANS FOR INSURING COMPLETE COMBUSTION OF COAL IN HEATING BOILERS.

Application filed August 10, 1920. Serial No. 402,731.

(GRANTED UNDER THE PROVISIONS OF THE ACT OF MARCH 8, 1921, 41 STAT. L, 1313.)

T all whom it may concern:

Be it known that I, Ronorrnn IVILLIAM BURGKHARDT, citizen of the Republic of Switzerland, residing at Mulhouse, Department of the Haut-Rhin, in France, and hav ing I. 0. address Rue Saint-Jean, in the said city, have invented certain new and useful Improvements in Means for Insuring Complete Combustion of Coal in Heating 10 Boilers (for which I have filed application in France, Aug. 1, 1919, and which eventuated in Patent No. 510,460, dated Aug. 1,

1919, and delivered Sept. 6, 1920; said invention has also been patented in Belgium, July 24;, 1920, No. 289,599; Great Britain,

July 30, 1920, N0. 149,67 7 Luxemburg, July 30, 1920, No. 11,894; and Italy, July 31,1920,

No. 534/97); and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention has reference to means for ensuring complete combustion of the coal used for heating steam boilers and it consists in a combination of devices whereby the different gaseous strata rising from the grate of a boiler furnace are intimately mixed, the quantity of coal fed to the furnace and the 0 column of air forced in being regulated in approximately the theoretic proportions, and the heat abstracted from the combustion gases in two stages, the mixing being effected between the said stages, substantially 5 as hereinafter described.

The invention is illustrated in the accompanying drawings, in which:

Fig. 1 is a diagrammatic vertical section of a device embodying the invention in its preferred form.

Fig. 2 is an enlarged detailed view of a portion of Fig. 1 relating to the device for mixing, initially, the air and gases.

Fig. 3 is a view similar to Fig. 1,showing the device slightly modified in certain details.

Figure 1 illustrates an application of the invention to a boiler comprising two cylindrical boiler drums 1- and 2 connected by means of a cluster of tubes 8. The grate t is of the endless platform type fed with coal from a hopper 5 and with air by means of a blower 6. A horizontal gas-tight partition ed to mix the gaseous strata, which device is preferably constructed as illustrated in Figure 2, but is not per se comprised in the present invention as it forms the subject matter of a. separate concurrent application for patent filed August 10, 1920, Serial ,No. 402.732. 13 indicates a stirring device by means of which the desired thorough mixing is accomplished.

To enable the steps in the progress of the phenomenon of combustion to be readily understood, the gases issuing from the furnace may be divided theoretically into three strata, indicated by the arrows 9, 10, 11, the stratum 9 with an excess of air, the stratum 10 with a mixture of air and combustible in approximately the theoretic proportions, and the stratum 11 with a great excess of. combustible.

The combustible is fed in by means of the hopper 5 and the theoretic volume of air is supplied by the blower 6; and the three gaseous strata traverse the passage across which the lower part of the cluster of tubes extends. In this passage the said gaseous strata become cooled to an extent which depends, it will be understood, upon the dimensions of this portion of the boiler, and these dimensions should be such that the gases are cooled to a temperature which does not bring them below a dull red colour, so that they can readily burst into flame again. In practice, this will correspond to a lowering of temperature of about 600.

These gases are not always mixed and they remain separated into three layers or strata, but they have lost so much of their heat that. intimately mixed and being consumed completely, their temperature will not exceed that which is dangerous for masonry. It is at this moment that the gases are mixed by means of suitable devices as illustrated diagrammatically in the drawing.

The mixing device referred to above which consists of transverse'tubes causes the fractionated strata to pass from one wall to the other is preferably employed. Mechanical devices made of suitable refractory material and cooled artificially, such as the rotary arms indicated by the reference numeral 13, may likewise be employed.

The gases, completely mixed and consequently completely consumed, pass up into the fine in which the upper part of the cluster of tubes is located and impart their heat to the said tubes.

hen the boiler is of large dimensions, the passages or flues become proportionately large, and the mixing problem increases in difficulty because the extreme strata are further separated from each other. In that case it is advantageous to sandwich, so to speak, a cross current of air between the various combustible strata, and this is effected by introducing secondary air through an opening 12, Fig. 1, which air follows the course indicated by the arrows 12. It will be realized that the mixing will thus be more easily eflected. This secondary air is of course not in addition tothe theoretic quantity of air forced in by the blower but is reckoned as part of the total theoretic quantity required for combustion.

Figure 3 shows another way of applying the invention to a boiler of the same type provided with a Riley grate. The mixing chamber inthis case is arranged at the front of the boiler, and a primary mixing device, such as described above, consisting of tubes 81 arranged crosswise, is arranged within ,the cluster oftubes above a baffle plate 71, as

indicated in the lower portion 14 of the flue. Complete combustion and the final transfer of heat tothe tubes take place in the upper portion 15 of the flue. In this figure, 13 represents a modified arrangement comprising a series of obstructions or baflies to further mix or cause a commingling of the gases, corresponding in effect to the rotary stirrers 13 shown in Figure 1.

Claims 1. In a furnace, the combination with means for regulating the quantity of coal fed thereto and the volume of air blown in, of a first boiler element which abstracts a portion of the heat from the combustion gases, cans for thereafter effecting a preliminary mixing of said gases, an obstructed passageway for subsequently causing a more thorough mixing of the gases thus cooled, and a second boiler element around which the complete combustion of the mixed gases and the final transfer of the heat to the boiler takes place.

2. In a furnace, thecombination wit-h means for regulating the quantity of coal fed thereto and the volume of air blown in, of a first boiler element which abstracts a portion of the heat from the combustion gases. astationary honeycomb structure for clfecting the preliminary mixing of the gases thus cooled, a rotary mixing device for Subsequently causing a thorough stirring of the gases and a second boiler element around which the complete combustion of the mixed gases and the final transfer of heat to the boiler takes place.

In testimony whereof I aflix my signature, in presence of two witnesses.

ROD. WILLIAM BURGKHARDT. \Vitnesses:

VILLIAM E. HOLLAND, FRIDEN LALADIN.

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