US1953767A - Air delivery apparatus for fuel combustion - Google Patents

Description

Ap 3, 1934. H. MEACHEM AIR DELIVERY APPARATUS FOR FUEL COMBUSTION Original Filed 1951 S'SheetS-Sheet l INVENTOR fizryjyzarfizm/ BY ATTORNEY April 3, 1934. H. MEACHEM 1,953,757

ua DELIVERY APPARATUS FOR FUEL comauswzon Original Filed Feb. 25. 1931 3 Sheets-Sheet 2 INVENTOR filrry flfmcirem ATTORNEY April 3, 1934- H. MEACHEM 1,953,767

AIR DELIVERY APPARATUS FOR FUEL COMBUSTION Original Filed Fe 25. 1951 s Sheets-Sheet s INVENTOR Harry Hear/um ATTORNEY Patented Apr. 3, 1934 UNITED STATES PATENT OFFICE AIR DELIVERY APPARATUS FOR FUEL COMBUSTION Harry Meachem, Teaneck, N. J., assignor to Todd Dry Dock, Engineering & Repair Corporation,

Brooklyn, N. Y.

1 Claim. (Cl. 15877) This application, which is a division of my application Serial No. 518,138, filed February 25, 1931, relates to apparatus intended for the delivery to burners of air supplies, both primary and secondary, for the efficient combustion of uel.

My investigations in fuel combustion have led me to believe that by causing the fuel to issue whirlingly into the combustion zone, and pro- 0 viding a concentric envelope of primary air flowing in contacting relation with the fuel, whirling in the same direction, and joining the fuel at the root of the flame, a condition is set up whereby the fuel and air, spinning at high rotative velocity, are induced to intermingle and blend into a more perfect mixture than has been availab by any of the methods in vogue.

This method of associating the fuel and primary air results in the production of a relatively short, bushy, flame, whose propagation proceeds whirlingly through an unusually prolonged rotative path, in which the fuel continues to burn in suspension with great efficiency.

The secondary air employed by me is caused to whirl in the same direction of rotation as the primary air and fuel, and is drawn into the flame over a deflector, thereby providing a large volume of air that envelopes the flame and supplies the necessary amount of oxygen to effect complete combustion. The flow of the secondary air is in undivided volume, by which is meant that it enters the furnace throat in a volutely moving mass, instead of being divided into streams by the use of vanes, as has previously been resorted to, and therefore the secondary .air is enabled to blend in with the other constituents of the flame.

Other features and advantages of my invention will hereinafter appear.

In the drawings:

Figure 1 is a face view of my improved fuel burning apparatus. v

Fig. 2 is a section on the line 2-2 of Fig. 1.

Fig. 3 is a section on the line 3-3 of Fig. 2, and

Fig. 4 is a section through the flame cone on the line 4-4 of Fig. 2.

In the drawings 1 indicates the usual Venturi ring, which is entered through an opening provided therefor in a furnace front plate 2, said ring 1 being connected with a box-like structure, through which air is supplied to the furnace for combustion purposes. This supply of air is termed the secondary air, and the air box is so constructed that it will cause the air flowing 'therethrough, under either natural or forced draught, to enter the furnace whirlingly through ring 1, in a volute, undivided volume.

To this end the air box has a partly spiral peripheral wall 3 that, with the ring 1, contains the fuel atomizer and primary air supply means. v30 But, whilst the burner and primary air supply means (which will both be described hereinafter) are centered within the ring'l, they are disposed eccentrically with respect to wall 3, being nearer that portion of the wall whence the flowing air 5 passes into ring 1 than to the portion of the wall where air has its entry into the air box.

The air box is bounded by a forward plate 4 and a back plate 5, except that a circular clearance in back plate 5 registers with the larger di- 7 ameter of ring 1.

The partly spiral form of wall 3 continues from a vertical wall portion 6, which latter, with the forward and. rearward plates 4, 5, and a base "I, provide between them an air inlet 8, that is con- 7 trolled by a damper 9, hinged at 10 near wall portion 6, and provided with a handle 11 for its operation, whereby the area of the inlet opening may be varied.

The partly spiral wall in its curvature gradu-- 3o ally restricts the area encompassed between it and the circle represented by the larger diameter of ring 1, meeting that circle about in a horizontal plane bisecting said ring, thence continuing in said circle, as wall portion 12, to a point, indicated at 13, approaching a vertical plane transversely bisecting the ring.

Said wall portion 12, plates 4 and 5 and base '7, unite to form a passageway, having inlet 14, for the inflow of additional air into the air box. The base 7 has an upwardly curved extremity 15 to aid in directing the air stream entering inlet 14 into the course of the air stream entering the air box through inlet 8.

From the foregoing description of the air box formation, with its partly spiral peripheral wall, within which the atomizer and primary air supply means are eccentrically located, and bearing in mind that the inlet portion of the air box is larger in area than the furnace throat reprem0 sented by the ring 1, and that the area of the air box becomes contracted toward the end of the partly spiral wall 3, then it becomes evident that the stream of air flowing to the furnace through the air box, concentrates in its spiral path and is caused to pass through ring 1 in a volute, whirling volume.

The manner in which this volume of secondary air co-acts with the mixture of fuel and primary air, will be referred to hereinafter, it now being no desired to describe the supply means for the fuel and the primary air.

The atomizer employed in my improved fuel burning apparatus, and illustrated herein, forms the subject of a companion case, filed February 25, 1931, with Serial No. 518,139, and only such features thereof will be described herein as are necessary for an understanding of the improvements comprised in this application.

Thus the atomizer has a casing 15' that contains a multiflanged spindle 16 which connects with the shaft 1'? of a motor 18 whereby said spindle is driven at high speed. Liquid fuel is introduced into thecasing 15 as by means of a tube 19, which receives its supply from a branch 20 of liquid fuel pipe line 21. The pressure under which liquid fuel is delivered to the atomizer need be only moderate, since the high speed at which the spindle rotates, which may for example be 3500 R. P. M., and the flanges on the spindle, which are spaced apart and provided with staggered communicating notches, drive the fuel whirlingly, and at great velocity, through the atomizer. The spindle is provided with a head 22, having a convex inner surface that lies opposed, in spaced relation to the outer, reamed end of casing 15, leaving a circularly inclined slit A for the emission of fuel, which thus is caused to issue in a whirling film, having a tendency ,to flare radially.

It is to correctthis latter tendency that I provide means for delivering at the root of the flame a hollow column of primary air, whirling at high speed in the same direction of rotation as the liquid fuel, to thereby restrict the radial area of the flame while permitting flame propagation to be continued in an extended circular path during which the fuel may burn in suspension.

These primary air delivery means comprise a blower like that forming the subject of my patent application Serial No. 484,358, filed September 25, 1930, and is here represented by the casing 23, containing the impeller blades 24, driven by the motor 18. Said casing 23, which may be circular in form, communicates at its periphery with a concavo-convex passageway 25 that is defined by the dished members 26, 27, which are in spaced relation in order to provide the passageway 25. The members 26, 2'? are connected by a series of curved membranes B that lie in the rotating flow path of the air, to thus avoid retarding the speed of flow.

The air box plate 4 is provided with a clearence to permit the projection of members 26, 2'7 therethrough into the air box, the member 26 having a central boss 28, whose forward portion serves as a bearing for the motor shaft 17, while its rearward portion is provided with an enlarged axial bore 29, to receive the forward portion of atomizer casing 15'. A tubular member 30 is placed concentrically about the atomizer casing 15', and has a forward enlarged portion 30 that is in screw threaded engagement with the rearward, terminal portion of member 27, said tubular member 30, with the casing 15, providing between them an annular passageway 31 that forms a continuation of passageway 25.

Passageway 31 terminates just anterior the fuel emission slit A, so that the supply of primary air, which is forced whirlingly by the impeller through passageways 25 and 31, at high speed, issues in a hollow rotating column into contact with the conoidal film of fuel that issues mean? from slit A, the fuel and air both rotating in the same direction and assuming a partly spherical form. The flame produced with this admixture of fuel and air is prevented from tailing out radially by the pressure of air that issues from passageway 31 and contacts the flame at the root thereof, because the fuel and air, both whirling in the same direction, circle together through a rotary path of unusual extent and time duration. Because the fuel is in suspension in the zone of maximum heat all through the period of rotative travel, thereby the process of combustion is enabled to be thoroughly performed.

Although the mixture of fuel and primary air, referred to, plus a suitable supply of secondary air affords excellent results, I have found that the addition of the secondary air by the improved supply means hereinbefore described, namely, whereby it is caused to enter the furnace whirlingly in undivided volute volume, rotating in the same direction as the fuel and primary air, thereby a perfect blend is effected between the several combustible elements, sufficient oxygen is supplied to support combustion, the speed of rotation is maintained, and the volume of secondary air becomes an enveloping mantle to further restrict the radial tailing off of the flame, tending instead to confine the flame in a whirling bushy mass.

A flame cone, indicated at 32 as surrounding the atomizer performs its part in the general efficiency of the apparatus, said cone providing a restricted, annular path between it and the ring 1 for the major portion of the secondary air, which thus joins the flame in its larger radius, whilst a series of angular slits 33 through the cone serve to supply some secondary air to protect the cone from the intense heat.

The slits 33 are so angled as to maintain for the air passing therethrough the same direction of rotation as the main volume of secondary air, because, as has been previously set forth, the speed of rotation of the combustible elements must not be retarded, and these elements, all whirling in one direction under their own impelling forces, blend perfectly in a homogeneous combustible mass.

Variations within the spirit and scope of my invention are equally comprehended by the foregoing disclosure.

I claim:

A liquid fuel burner comprising means for spraying fuel into a combustion chamber in a whirling stream, a casing including dished members arranged in spaced relation to define a passageway extending concentrically with said spraying means, rotatable air impeller means mounted within said casing for delivering a hollow column of primary air by way of said passageway, about the fuel stream, a ring disposed concentrically with said passageway and a secondary air supply box positioned between said ring and casing and arranged eccentrically of said ring, said box having an inlet and including a partly spiral wall whose curvature approaches the center of said ring to form a progressively restricted continuous passage extending from said inlet in the direction of rotation of said primary air impeller means for delivering a volutely whirling undivided volume of secondary air to envelop the fuel and primary air, its direction of rotation being the same as that of the primary air.

HARRY MEACHEM.

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