US2162051A - Oil burner - Google Patents

Description

June 13, 1939- E. c. BALLMAN 2,152,051

on. BURNER Filed May 5, 1934 2 sheets-Skiset' .1

.I une 13," 19,39. E. C. BALLMAN OIL BURNER Filed May 5, 1934 2 Sheets-Sheet 2 Patented June 13, 1939 UNITED :PATENT OFFICE t '011. BURNER Edwin o. Bauman. si. Lpuis, M0. Appiicatiqii May 5, 1934, serial No. 724,071

f claims. (01.158576) This invention pertains to liquid f uel burners, such as may be used for ring Idomestic furnaces.

One of the objectsoffthis vinventionis to pro- 5 vide an improved burner ,nozzlefor liguid. fuel adapted to provide improvedatomiza'tion f the fuel. A

Another object is to provide/ such a burner properly shielded from ftheuaction of air currents so as to control the llame. y

Another object is to provide a simple Vstructure and mounting, for such a. burner which may easily be applied to rexisting furnaces.

Another object is to provide improved means for burning liquid fuel in a furnace, Y 'Y Another object is t0 provide such a device of simple construction which may be cheaply manufactured.

Further objects will .appear'vfrom the Yfollowing description taken. in connection ,with the accompanying drawings, irl-which:

Figure l is an Aenlarged, sectional detail of a burner embodying this nvention;

Figure ,2, is a vertical ysectional view of the burnerandits mountnein the .fzllruaei v Figurev 3 isaperspeotive detail oi the burner head; i,

Figure 4 is a. sectional. detail ...Somewhat .enlarged takenon line` iz-f4. .QfF.ig11IQ.l51f

Figure 5 is a view shovvingtheinstallation of the burner inthe furnace. i

This application .a contmuatiou in part, of application Serial No; 565,459, filed September 28,1931. f

Referring to uthe,acco pan yin g drawings, I designates aufurnace of any s uitable type./` This may be a hotagl furnacaasteam boiler, or any other type of heating .unit The furnace l is usually provided with a iredoor and thedoor- 40 Way is usually provided by a casting having a flange 3, extending around the door opening. In vaccordance with this invention a bracket 4 is provided which may be mounted withinthe doorway by means ofsetrscre'wsS and G, as indicated in Figure 2. Upon the bracket 4, the burner nozzle may be .mounte'd This nozzle will be described in detail hereinafter. The

bracket 4 is easily removable from the doorway, at any time, by simply lf'ic'nslen'ir'ig4v the screws 5 and 6.

Referring now more particularly to Figures 1, 2, and Bfthep'i'pe 40 delivi'sa mixture of oil and air to a burner tipcoiiipris'ing a liad 52, equipped with ai fuel duc-t 53, ,extending'through the middle thereof.,v Theiiead' Vvis' provided `the rim of the plate 60.

'with a nipple 54 adapted to receive a hollow cap A55, provided with a center perforation 56. Loosely mounted within the cap 55 is a plug 51. This plug is generally cylindrical in form', but is providedl on its outer periphery with a series o f lon- 5 gitudinal grooves or flutes 58. These grooves 58 provide a series olf longitudinal passages VVspaced outwardly from the center ofthe plug 51. The end of the cap 55 converges beyond the plug 51 sothat fuel flowing through the grooves 58 10 is converged upon the center perforation 56.

Mounted on the head 52, by means of screws 59 is an elliptical guard plate 60. The plate 60 vis provided wi-th a pair of downwardly extending posts B'lhup'on which is mounted a circular 16 baffle plate 62, provided with an enlarged centra] Vopening 63 opposite the perforation 5G.

Mounted on a bracket 54, which in turn is mounted on the bracket 4, is an air tube 65.

-The tube 65 surrounds the tube 40, and is cut 20 off at its forward end at an angle so as to iit The head 52A may be secured to the tube 65 as by a screw 66. The rear portion of the Atube 55 is connected by a bracket 61 with the pipe 40 so as to hold these 25 parts inxed relation to each other.

Also mounted on the bracket 64 Vand suitably `insulated therefrom is a pair of spark terminals 68, only one of which appears in the drawings. The terminals .68 are .positioned between 30 the head 52 and thebaiiie .62. in a position to ignite the `fuel issuing from the burner tip.

'Ihe head 52 is elongated so as to bridge an opening `69 in the plate 60, `leaving the lateral parts of said opening clear. On the other side 35 o f the plate is aflange 1i) surroundngthe opening 69 and extending ldownwardlysubstantially to theend of the cap 55, being slightly inturned atits end.

A housing 1I may be mounted on the bracket 40 4 so as to enclose the rearuof the burner nozzle and may be providedvvith a perforation 12, through whichv the pipe 40 may be entered. This housing may be of sheet metal, or other suitable material, and also provides" an air passage 45 r for ,air moving Vtoward the burner nozzle. yThe operation of'this burner is as follows The apparatus having been suitably installed on the furnace with' its control devices such as a thermostat in the room to be heated, a stack 50 relay and a maximum temperature relay in the air chamber of the' furnace, the several control devices are suitablyeonnected to the pump motor I3, as indicated in Figure 5, the cable 16 also passing to the spark terminals 68. When a 55 l Y a predetermined point.

temperature drop causes operation of the thermostat, the motor I3 is started and a spark appears at the terminals 68. The motor I3 operates to drive an air pump I4 and a fuel pump 2'I. These pumps operate in unison and at a predetermined speed. Accordingly, they supply air and oil in fixed proportions and at a definite rate. The air and oil are conveyed by the pipe 40 to the burner nozzle. The oil in -the pipe 46 is not necessarily atomized, but probably flows along the Walls of the pipe, being carried along to a great extent by the rush of air through the pipe. When this mixture arrives at the head 55, the flow of both oil and air is sub-divided and spread out so that a portion thereof flows through each of the grooves 58. After passing through the grooves 58, the mixture encounters the converged tip of the cap 55 and is turned inwardly thereby. The resul-t is that a plurality of mutually converging jets is formed within the cap 55. 'These jets meet at the perforation 53 and impinge upon each other at a high velocity. It has been found that this results in a complete atomization of the fuel and thorough mixing thereof with the air. Accordingly, Va thoroughly atomized supply of air and fuel mixture is projected from the oriilce 56 and through the opening 63 in the baille plate. The ignition terminals 68 are positioned to project a spark into this jet of fuel and accordingly the latter is ignited and aV flame is projected through the opening 63.

It will be noted that the tip of the nozzle is directed downwardly at an angle. In installing this device, the furnace grate is covered with an irregular mass of refractory material, such as broken fire brick. The downwardly projecting flame impinges upon this massof refractory material heating the same and scattering the flame to 'some extent and at the same time its progress is arrested so that from this point the products of combustion may rise in the re box.

The issuance of the fuel mixture at a high velocity from the orifice 56V produces a suction in the annular space surrounding the cap55 and within the flange 10. 'I'his space being open to the pipe 65, air is drawn in through that pipe, which air issues at the end of the flange I0 and is delivered to the ilame at its origin. Asthere is a tendency for the suction induced by such an issuing jet to draw in air from all the space surrounding the burner tip, such a draft of air sometimes causes trouble by blowing out the flame. In order to eliminate this effect the baille 62 acts to prevent such a movement of air in the vicinity of the origin of the flame. v

As stated above, the flame is projected downwardly upon the refractory material on the grate, which becomes heated and then directs the products of combustion upwardly in the fire box. In order to insure complete combustion of the fuel thev lower draft door 'Il may be provided with an adjusting device, such as a screw 18, whereby it may be set at a definite opening. Accordingly, the movement of hot gases upwardly in the fire box induces a draft into this draft door which assists in the perfect combustion of 'the fuel.

The device continues to operate in this way until the temperature at the thermostat rises to The thermostat then acts to stop the motor I3, and cut off the ignition. The furnace now remains idle until the temperature has again fallen to the minimum point at the thermostat, whereupon the cycle of operation is repeated.

In the operation of the furnace'with the burner soA installed it will be noted that primaryV air is supplied through the conduit 40 along with the oil, which ingredients, upon atomization of the oil, combine to provide a combustible mixture which may be ignited. Secondary air is drawn in bythe aspirating action of the burner jet through the housing 1I and the tube 65. This air is passed into the flameunder the control of the baille 62. The flame strikes downwardly,

against layers of refractory material IOI and H12, lining the fire box, after which it is reflected upwardly to rise in the ilre box. The layer IIII may be composed of broken fragments of fire brick or the like about the size of an egg and piled to a suitable depth to protect the grate, on which it provides a porous mass through the pores or interstices of which air may pass upwardly. The layer |02 may be a lining of refractory material to protect the side walls of the furnace. This upward movement induces an indraft at the door 1l, which draft passes upwardly through the grate and through the layer IIJI and provides tertiary air to support the combustion of the fuel during the rise of the flame from the grate up Vthrough the fire box. The nal products of combustion are eventually discharged through the stack in the usual manner. f

It will be seen that this invention provides a burner in which atomization is accomplished in an effective manner so that more complete atomization is obtainable. It willbe noted that the oil in arriving by the tube 40 is carried in by an air blast so that it is sub-divided into small particles. This condition is expressed in the appended claims by statingthat the fuel is in particled condition. The fuel being thus in particled condition is caused by the jets to move in a plurality of intersecting paths, these paths crossing each other substantially at a common point. Under these conditions the particles carried in the various jets are forced into collision with each other and since they move at a high rate of speed, such collision occurs under intensive impact and the particles are broken into innumerable smaller fragments. In this manner a very minute atomization is obtained. With the fuel thus perfectly atomized, it may be burned with complete combustion by supplying a proper quantity of air. This, as has already been described, is supplied in three ways. It will be noted that the air is delivered to the mixture in successive stages. The primary air arrives with the oil and is mixed with itat the instantV of atomization so that a very intimate mixture is obtainable. This is a rich mixture and ignites readily when the spark is encountered. The secondary air enters the flame immediately after ignition and promotes the development of the flame in the downward direction. After striking the bottom and walls of the fire pot and being reflected upwardly, the flame is supplied withY tertiary air which completes the combustion. In this manner it has been found that a flame may be produced which develops in a comparatively gradual manner. Accordingly, the noise which usually accompanies a blast flame is practically Y entirely eliminated. Y

The mounting of this burner is such that it may be installed in an existing furnace by any one having a moderate knowledge of mechanics. It is installed Without altering the furnace. Furthermore, in case of a failure of oil supply or of electric current the burner may be removed from the furnace door by the simple manipulation of a few screws after which the furnace may be fired by hand with coal or the like. This is a convenient feature when the burner is installed in rural districts Where the liability of frequent failure of electric supply is greater than in municipal districts.

While certain theories have been advanced to explain the action of the burner, it will be understood that applicant does not intend to limit himself to any particular theory of operation, as use of such theory was for the purpose of explanation only.

It will be understood, of course, that while the device has been described as a unitary burner system, various individual features or sub-combinations thereof, may be useful by themselves without reference to other features, and accordingly, the employment of such individual features and sub-combinations is contemplated by this invention and within the scope of the appended claims.

It is further obvious that various changes may be made in the details of construction, within the scope of the appended claims without departing from the spirit of this invention; it is understood, therefore, that this invention is not limited to the specific details shown and/or described.

Having thus described the invention, what is claimed is:

1. A liquid fuel burner for a furnace, comprising, a burner nozzle having a tip provided with a fuel exit opening, means in said nozzle providing spaced fuel ducts adapted to divide the stream of fuel into a plurality of small jets, guiding means in said nozzle adapted to converge such jets to a common point at said opening so as to cause the jets to impinge upon each other as the fuel issues from said tip, a housing surrounding said tip and having an opening through which the tip projects so as to leave therebetween an annular air exit opening, and an air-supply duct communicating with said housing and open to the atmosphere at its rear end.

2. In combination with a combustion chamber, a liquid fuel burner comprising, a conduit thru which the fuel may be propelled by an air stream, a burner nozzle having a passage arranged to receive the fuel and air from said conduit, said nozzle having means to subdivide the flow of both air and fuel into a plurality of spaced paths, and converging guiding means having a narrowedged outlet orifice at the apex thereof, whereby the separated flow is converged to said orice in streams intersecting therebeyond to atomize the fuel, and a transverse baiiie plate mounted just beyond said orice and having an opening thru which the atomized mixture is projected, said plate being arranged to obstruct a draft tending to blow out the flame.

3. In the art of burning liquid fuel, the process comprising, forming fuel and air into a series of jets wherein the fuel is propelled at high velocity by the air, directing the jets so as t0 impinge upon cach other in order to form a spray of finely atomized fuel mixed with air, directing the spray downwardly in the furnace, adding secondary air to the atomized spray at the point of formation thereof, igniting the spray so as to cause the same to project a flame downwardly in the furnace, and adding tertiary air to the name at the bottom of the furnace.

4. A burner for liquid fuel, comprising a conduit through which the fuel may be propelled by an air stream, a burner nozzle having a passage arranged to receive the fuel and air from said conduit, said nozzle having means to subdivide the flow of both air and fuel into a plurality of streams of both air and fuel, converging guiding means having a narrow-edged outlet orifice at the apex thereof, whereby the subdivided flow is converged to said orice in streams intersecting therebeyond to atomize and mix the l.

fuel and air, and means to supply combustion air to the resulting mixture.

5. A liquid-fuel burner for a furnace having a combustion chamber, comprising, a burner nozzle, means for supplying fuel and air to said nozzle, means in said nozzle for forming the fuel and air into an atomized spray of mixed fuel and air adapted upon ignition to form a flame, and a baffle provided with a central opening through which the spray passes and positioned circumferentially and forwardly of the spray opening of said nozzle in the path of air currents approaching the flame from the rear of the nozzle and tending to blow out the flame.

EDWIN C. BALLMAN.

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