US2982235A - Cyclone furnace burner - Google Patents

Description

May 2, 1961 Filed Nov. V9, 1954 A.VJ. GRAM, JR Erm.l 2,982,235

CYCLONE FURNACE BURNER 2 Sheel'.s-Sheel'l 1 INVENTORQ ARTHUR J. GRAM, JR.

WARNIE L. SAGE g; g A BY ATTORNEY May 2, 1961 Filed Nov. 9, 1954 A. J. GRAM, JR., ETAL CYCLONE FURNACE BURNER 2 sheets-sheet 2 ARTHUR J. GRAM. JR-

BY WARNIE A SAGE W ATTORNEY;-

United States 3 Claims. (61,110.48) i Y The invention herein disclosed relates to improvements in 4the construction and operation ofV furnaces, of the cyclone type, and more particularly to ,the provisions, for

atent O f supplying fuel and air `to such? furnaces. As'disclosed, for

As customarily constructed, a cyclone typefurnace is, Y

of generally circular cross section about a substantially horizontal axis and provides an inner combustion chamber, of similar cross-section through which the burning. fuel and air are caused to move in a substantially. helicalpath along the circumferential wall on being introduced in `a high velocity stream from a cylindrical fuel inlet chamber, or primary burner, adjacent one end. In prior constructions, all fuel to be burnedis introduced into the primary burner chamber tangentially, in a high velocity stream of primary air carrying thesolid fuel particles in suspension; the majorportionof the combustion air being,` supplied as preheated secondary airA through a tangentially arranged airA inlet extendinglengthwise of the main combustion chamber. It has also been customary Vto provide 2,982,235 Patented May 2, 1961 ICC 2 trained by the whirling body of air and thus be carried thereby into the main cyclone chamber where combustion 1s completed in the manner described in the aforesaid Patent No. 2,594,312. In the present structure, kthe whirling body of air, directly adjacent the circumferential wall of the burner, serves to maintain the entering, fuel particles away from that Wall, or. at least to lessen the pressure attwhich such solid particles might be caused to engage the'wall if brought into contact therewith during their circumferential movement through the burner.

The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this specification. For a better understanding of the invention, itsoperating advantages and specific objects attainedby its use, refer#` enceshould be had to the accompanying drawings and de-v scriptive matter in which certain specific embodiments of the invention are illustrated and described. V

Of the drawings:

Fig. l is a side viewof a cyclone furnace unit constructed in` accordance with the present invention;

Fig. 2 is an end view, partly broken away, showingthe cyclone furnace unit of Fig.- l as viewed from the lleftof Fig. l;

Fig'. 3 is an outer end view of a guide cone forming part of the cyclone furnaceassembly;

Fig. 4 is a plan view of the'guide cone shown inl-lig. 3 and v Fig. 5 is a central: station of the guide cone takenk along line 5-5 of Fig. 3. f

As shown in Figfl, the cyclone furnace 10 is basically ofthe same general construction as the cyclone furnace illustrated and described in said U.S. Patentr2,5-94,312. Accordingly, the furnace may suitably be fired with a crushed or granular fuel, such as bituminousor semibituminous coal which, in the embodiment shown, is delivered-thereto from an overhead feeder 12 of known type as represented for example by the apron-type feeder disclosed inthe copendingY application of George A. Watts, Serial No. 157,859iiled April 25, 1950, now Patent No. 2,697,508. However, in using such a feeder for purposes,

of the present invention, there is no necessity for .con-` for a whirling stream of preheated tertiary air tothe i supplied from an adjoining chamber and introduced axially of the primary air-fuel stream within the primary chamber. t

It has been found thatby introducingthe primary airf fuel mixture into a cylindrical burner chamber in a generally tangential direction, so asto move ina helical pathalong Vand in contact with the circumferential wall of the.chamber, athigh` velocities, the peripheralchamber wall areas which serve as directingsurfaces for the mixture are subject to considerable ,abrasive wear. For this reason, a liner of wear-resistant material, suitably in the formV of replaceable blocks, has generally been installed along inner circumferentialrwall areas of the burner, particularly in a region adjacent the fuel-air inlet into the burner. Whereas such blocks have been effective in protectingthe, metal wall areas for limited periods, it has nevertheless been found necessary to replace certain of thel blocks after relatively short periods' of service, and particularly those blocks located in the'qua-drant nearest thefuel and air inleg-'thereby adding to the overall cost of maintenance.

Y In accordance with the present` invention, primaryLair and fuel are normally introduced separately into the primary burner; the primary air being introduced as a high velocity stream directed tangentially of the circumferential wall of theburner whereby there is created and main. tained a central vortexregion of minimum pressure into which the granular fuel isl directed axially so `as'to be en,

In more detail therefore, the cyclone furnace unit 10l comprises a main combustion chamber 14, and an adjoining fuel inlet chamber or burnerlS, both of which chambers are cylindrical in form and substantially circular in cross section about a common. longitudinal axis which, in the selected illustrative embodiment, is inclined downwardly from the outer fuel inlet end of the unit at an angle of about 5. The cyclone chamber 14 s: mainly defined Vby an outer circumferential wall 16a, and transverse walls 17 and 18 arranged at opposite ends; all of such Walls usually including fluid conducting tubes, not shown, except as illustrated at 19, specifically for the, inner end wall 18. The outer end furnace Wall 17 is tapered to define a central circular inlet 21 through which the whirling body of primary air and fuel is adn'littedr fromburner 15;` the inner end wall 18 beingy planar and formed with an inwardly projecting, tapering throat 23 which defines a central gas outlet 24; the wall 18 also being formed with a slag outlet 25 leading from alower part ofthe chamber. A secondary air linlet 27, of elongated-'rectangular cross section, opens tangentially into the cyclone chamber 14 at a location intermediate its ends, suitably adjacent the tapering circumferential chamber 29 to which primary air isy admitted tangentially cross section ing 3l to which is connected an involute curved air supply conduit 32 having a pivoted air control damper-33 therein; the conduit 32 being shown as having an upper extension terminating in a flanged end 34 for connection to a suitable source of air under pressure. The inner circumferential wall surface of the burner is lined with replaceable wear-resistant blocks 35 which provide an inner circumferential wall surface formed as a continuation of the inner curved wall surface of supply conduit 32.

Burner 15, at its outer end, is formed with a conical end member 36, concave toward the interior of the burner, with an apex angle of 90, or thereabout, and fitted with a curved fuel inlet p'ipe 37 through which solid fuel in relatively coarse particle form is fed at regulable rates to the inner conical space 38 where the solid fuel particles are directed into the low pressure region of the vortex created by the whirling movement of primary air within the burner chamber 29. The pipe 37 forms the lower end portion of a valved conduit system 39 which leads downwardly from the fuel discharge spout 4l of feeder 12, and opens into the inner conical space 38 at the burner side of cone 36 at a location superjacent the apex. If desired, a cross-connection 39a, having a valve 40 therein, may be installed between an upper extension of the air supply conduit 32 and the fuel conduit system 39 in order to include a limited amount of primary air with fuel entering the conical fuel guide member 36. Iln operation, the fuel particles are entrained by the whirling body of air within chamber 29 and caused to move in a helical path therewith and thus enter the main combustion chamber 14 where the burning process is completed as disclosed in the aforesaid Patent No. 2,594,312; the resulting gases of combustion being discharged through the central gas outlet 24 at the downstream end, and residual slag being discharged in molten condition throughthe lower slag outlet 25 at the same end.

The conical guide member 36 is formed throughout its circumference with a double wall having outer and inner conical plates 42, 43 spaced apart to define an intermediate space 45 for accommodation of a cooling Huid which may suitably be circulated therethrough between inlet and outlet nipple connections 46, 47 which are in communication with widely separated portions of space 45, preferably at lower and upper locations to allow for either natural or forced circulation of a cooling liquid therethrough. Both plates 42, 43 are peripherally welded to an annular ange 48 for suitable attachment by screws, for example, to a companlonate flange 49 formed on the outer end of burner( chamber l5. Openings 51, 52 are formed in the respective plates 42, 43 for the insertion of fuel inlet pipe 37 which is sealed to both plates, as by weld metal, throughout the perimeters of both openings. The inner end, or edge, of the inner, fuel-directing plate 43 is preferably arranged so as to lie substantially in a common plane, normal to the central burner axis, with the axially outer edge of the primary air inlet 31, in order to obviate a recirculating movement of fuel which might otherwise be initiated and malntained adjacent the inlet end of the burner and thereby result in excessive wear of the inner circumferential burner surface in that region.

While in accordance with the provisions of the statutes we have illustrated and described herein a specific form of the invention now known to us, those skilled in the art will understand that changes may be made in the form of the apparatus disclosed without departing from the spirit of the invention covered by our claims, and that certain features of the invention may sometimes be used to advantage without a corresponding use of other features.

l What is claimed is:

1. A cyclone furnace having a combustion chamber of substantially circular cross-sectiondefined by walls including fluid cooled tubes, means defining a substantially unobstructed primary air inlet chamber of cu'- cular cross-section and of smaller diameter than said combustion chamber and having an 'outlet at one end concentrically opening into one end of said combustion chamber, means for introducing a stream of primary combustion air tangentially into said inlet chamber at a high angular velocity and effecting a whirling path of air travel therein along the circumferential wall thereof to form a central vortical region of minimum pressure in said inlet chamber, m^ans forming a substantially unobstructed fuel inlet chamber of circular cross-section having an outlet concentricaliy opening into the opposite end of said primary air inlet chamber, means forming a restricted gas outlet at the opposite end of said combustion chamber, means for introducing a high velocity stream of s^condary combustion air into said combustion chamber tangentially to the circumferential wall thereof at a location between the point of the fuel entry and the gas outlet, and means for introducing a slag-forming particulate fuel into said fuel inlet chamber and within said central vortical region ata velocity considerably lower than the volocity of the primary air entering said primary air inlet chamb:r,said last named means including a conduit opening to said fuel inlet chamber at a position inwardly of the stream of primary combustion air entering said primary air inlet chamber and opposite said central vortical region of said primary air inlet chamber.

2. A cyclone furnace having a combustion chamber of substantially circular cross-section arranged with its axis substantially horizontal and defined by walls including liuid cooled tubes, means defining a substantially unobstructed primary air inlet chamber of circular crosssection and of smaller diametr than said combustion chamber and having an outlet at one end concentrically opening into one end of said combustion chamber, means for introducing a stream of primary combustion air tangentially into said inlet chamber at a high angular velocity and effecting a whirling path of air travel therein along the circumferential wall threof to form a central vortical region of Yminimum pressure in said inlet chamber, means forming a substantially unobstructed fuel inlet chamber of circular cross-section having an outlet concentrically opening into and registering with the opposite end of said primary air inlet chamber, means forming a restricted gas outlet at the opposite end of said combustion chamber, means for introducing a high velocity stream of secondary combustion air into said combustion chamber tangentially to the circumferential wall thereof at a location between the point of fuel entry and the gas outlet, and means for gravitationally introducing a slag-forming particulate fuel into said fuel inlet chamber and within said central vortical region including a conduit opening to said fuel inlet chamber at a position inwardly of the circumf'rential wall of the primary air inlet chamber and opposite said central vortical region of said primary air inlet chamber.

3. A cyclone furnace having a combustion chamber of substantially circular cross-section arranged with its axis substantially horizontal and defined by walls including fluid cooled tubes, means defining a substantially unobstructed primary air inlet chamber of circular crosssection and of smaller diameter than said combustion chamber and having an outlet at one end concentrically opening into one end of said combustion chamber, means for introducing a stream of primary combustion air tangentially into said inlet chamber at a high angular velocity and effecting a whirling path of air travel therein along the circumferential wall thereof to form a central vortical region of minimum pressure in said inlet chamber, means forming a cone-shaped substantially unobstructed fuel inlet chamber of circular crosssection having an outlet at its base end concentrically opening into and registering with the opposite end of stricted gas outlet at the opposite end of said combustion chamber, means for introducing a high velocity stream of secondary combustion air into said combustion chamber tangentially to the circumferential wall thereof at a location between ythe point of fuel entry `and the gas outlet, andmeans for gravitationally introducing a slag-forming particulate fuel into said fuel inlet chamber and within said central vortical region including a conduit opening to said fuel inlet chamber at a position inwardly of the circumferential wall of Y the primary air inlet chamber and opposite said central vortical region of said primary air inlet chamber.

References Cited in the file of this patent UNITED STATES PATENTS 1,411,846 Donaldson Apr. 4, 1922 1,425,145 VSmith Aug. 8, 1922 2,560,076 Bloomer July 10, 1951 2,594,312 Kerr et al. Apr. 29, 1952 Y FOREIGN PATENTS 350,051 Great Britain June 11, 1931

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