US2227195A - Oil burner - Google Patents

Description

R. E. MOULE OIL BURNER Dec. 31, 1940.

Filed Oct. 5, 1958 INVENTO Patented Dec. 31, 1946 UNirED STATES PATENT orifice The invention relates toimprovements in oil burners, and consists preferably in the novel arrangement and construction of parts whereby a hearth having a central oil and air distributing means is bordered by a pronger cast-metal vaporizing ring of relatively high heat conductivity,

' and having an inwardly extending sheet-metal ignition shelf of relatively low heat conductivity,

the hearth being further provided with an auxiliary thermal-controlled preliminary air supply.

An object of the invention is to make a burner of simple and durable construction that will lend itself satisfactorily for automatic operation.

Another object is to make a burner which will promptly ignite and .provide a combustible mixture of oil and air suitable for cold starting, and then automatically adjust such. mixture to burn during normal running without soot.

Another object of the invention is to make a furnace that will give a noiseiess yet most emcient combustion of vaporized oil and air.

Other objects will be apparent from the following description when taken in conjunction with theaccompanying drawing, in whic Figure l is a cross-sectional view of one embodiment of the oil burner.

Figure 2 is a plan view on the line 2 2 in Figure l.

Figure 3 is an enlarged perspective View oi a section of the combustion ring and ignition shelf.

Figure 4 is an enlarged perspective view of the automatic auxiliary air control.

Figure 5 is an enlarged fragmentary sectional perspective view of a modiiied form of combustion ring and ignition shelf.

Figure 6 is an enlarged fragmentary sectional perspective view of a further modified form of combustion ring and ignition shelf with a gas type igniter.

The present invention relates more particularly to the type of burner shown in my Patent No. 2,175,539, dated October 10, 1939, and wherein it is explained that the oil from the center distributer head is thrown horizontally outward against the base of a surrounding ring by the centrifugal action of the small bore distributer tubes, whereas the air in contrast is regulated at the inlet damper, so that only a very small volume passes through the rotating head.

Thus it must be understood that there is absolutely no force to the air delivered by the distributer head any more th-an there can be force for projection purposes at the outlet of a large open-ended hose when the feed supply` at the faucet is cut down to a dribble.

This fact concerning the air delivery is most important because it distinguishes the present invention from all prior art or practices as far as is known to me: that is, no air is fanned or forced into contact with the oil, but instead the air is admitted quietly about the central diffuser, and is left to gradually und its contact with completely vaporlzed oil, resulting in a positively quiet iiame oi Bunsen type forming a dome above the central projector. The gradual admittance of air about the central diuser also protects the distributor head or cap, so that tin-plating on the sheet-iron top to prevent rust prior te use is not burned or deteriorated when the burner is in actual service even for a period oi years.

it is believed important to set forth the fundamental principle oi operation or my burner in order to distinguish the saine and to appreciate the .essential details, as otherwise many burners described in prior patents would appear substantially similar in construction and possible operal tiem Referring .to the drawing, Figures l. to inelusive, in which like numerals of reference lndicate corresponding parts in the several gures, a furnace iii is illustrated which may be of any type, provided it has an under chamber it and a iire chamber i2 separated by a noci i3 preferably formed of refractory material properly supported as on a plate Mi extending between the flanges it of the furnace side Wall, and also having an air inlet opening l@ as is usually provided by the ash-pit door in a coal-red furnace. The nre-chamber of the lfurnace also has the customary discharge ue (not shown) p The rire chamber door it has a central opening in which is rred upper and lower ange rings il and viii, and between which is arranged a pair of radially-slotted damper plates i@ to adjust the quantity of air passing through the central opening in the re chamber oor i Ii.

The lower flange ring it is supported on the furnace foundation by adjustable posts 26, and in turn the ring I8 supports the motor 2l through the medium of the cross-piece 22 and the adjustable suspension bolts 2.3. The motor 2l is adjustably mounted vertically as shown, and its shaft 2d extends upwardly through the re chamber floor central opening, and has an inverted oil distributor cup 25 mounted thereon and rotatable in but practically closing a central opening in the damper plates i9.

The oil distributor cup 25 has an inwardly and upwardly turned flange 2B about its open lower end, to which oil is automatically fed by a tube as weli understood in the art and which forms n part of this present invention. f

'I'he oil distributor cup also has substantially L-shaped sheet-metal supporting arms 21', shown as four in number, secured to the top and supporting the cover-plate 28 a comparatively considerable distance above the nre-chamber floor whereby the limited supply of air carefully adjusted by narrow radial slots in the damper plates il may pass freely into the nre-chamber and practically float about the distributor head comprising the centrally supported motor, its shaft with the oil cup and cover-plate, and also two oil slinger tubes 28 leading from the closed upper edge of the oil cup in an outward curve to 'beyond the periphery of the cover-plate 28.

Continuing with the construction detailsa vaporizing ring 30 is arranged aroundI the firecham'ber floor I8. This vaporizing ring is circular and shown fitted close to the side wall of the nre-chamber, which is preferably circular but need not be so, as the identical circular Vaporizing ring has operated quite satisfactorily in a square fire-chamber, and it is therefore not essential that the ring be close to the fire-chamber wall. l

The vaporizing ring may be-made of refractory material, and it has generally been considered necessary to use such material in order to withstand the intense heat due to a wall type flame propagated and continuing about the ring, but

I discovered that such concentrated ame was not the most eiilcient, and only va, supporting or vaporizing combustion was necessary at the ring, and that vaporization could best be obtained by using a metal ring of comparatively high thermal conductivity such as iron, and that the intense combustion should be above and entirely clear of the vaDOrizing ring.

The cast-iron vaporizing ring 30 is preferably made in four quarter segments, and comprises the base 3l and the rows of upstandlng fingers 32.

The base in Figures 1, 2 and 3 is shown formed with an inwardly projecting ledge 33, having a trough 34 and over this trough is secured a light sheet-metal igniter ring 35 forming a shelf with the edges slightly upturned to form a shallow depression. This shelf is fastened to the ledge 33 as by lrivets 38, whereby it is seated firmly on the ledge 33, but only contacts with the same at each edge due to the trough 34, as clearly shown in Figure 3. 'I'his is for the purpose of insulating the shelf from the ledge.

It is further important to this present invention that this shelf be made of metal of com- 31 as shown particularly in Figure 3, so that they may overlap the adjacent shelf-sections.

The burner is shown equipped with automatically energized insulated electric ignition electrodes 3 8, as is well understoodin the art, and therefore do not require further explanation as they form no part of this present invention.

vils more fully explained hereinafter, in the 21 stationarily supported on the cross-piece v22, all

operation ofthe invention the burner requires some auxiliary air when first started, and this is supplied automatically, preferably as shown through an opening 38 in the iioor of the firechamber by means of a tube 48, more particularly shown in Figure 4.

'Ihe tube 4l has a flanged top 4I with a raised inner valve seat 42, and is fitted with a flat disc valve 43 centrally supported as by a rivet 44 at the free end of a bi-metal goose-neck 45, the anchored end of the bi-metal being secured as by a rivet 48 to the flange 4l of the tube. This valve is set in position in the iioor I3 of the fire-chamber as shown in Figure 1 when the floor is being laid on the plate l'4, and the bi-metal holds the valve open when the fire-chamber is cool, and is arranged to close the valve firmly on its seat when' the fire-chamber becomes heated under normal running conditions.

Figure 5 shows a modification of the combustion and igniter rings, wherein the vaporizing ring is formed as a plain upstanding ring 41, with a bevelled top 48 from which the fingers 48 project, and the igniter ring 50 is a plain shelf with an inner ange 5I secured to the ring 41 as by rivets 52, the tabs 53 at the outer edge supporting the shelf clear of the floor I3.

In Figure 6 the vaporizing ring 54 is practically leaned against the furnace wall, and the igniter shelf 55 is a mere scoop and fastened thereto as by rivets 58. This figure also shows a gas pilot 51 for starting ignition, as it must be understood that the invention is not limited to any special ignition device or exact shape or placement of Darts.

In the present inventionA it must be emphasized that the oil is directed to'the vaporizing ring, while contrary to past practice the air is quietly released about the distributor head to supply a natural air content to the fire-chamber.

When the automatic controls, with which the present invention is not concerned, initiate the operation of the burner, the fire-chamber is comparatively cool, and the thermostatic bl-metal 45 on the auxiliary air supply is suspending the valve 43 olf its seat, and thus extra air is admitted through the tube 40 in the nre-chamber floor. At this time the oil supply is turned on and the motor of the distributor head is started and revolves the oil cup 25 with its slinger tubes 29 projecting oil laterally against the vaporizing ring 30. Y

The automatic control also energizes the ignition electrodes 38, and as these parts function the oil impinging against the vaporizing ring spatters and some flows down onto the igniter shelf where the electrode spark ignites the thin film of oil, and because the ignition shelf is made of a lowheat conductivity metal and is well insulated, the initial oil flame rapidly heats and ignites the adjacent oil, and quickly spreads around the entire shelf.

The circle of re around the ignition shelf in turn heats the vaporzing ring and fingers which are made of a metal of high conductivity, and in turn the oil on and about the vaporizing ring ignites and burns.

So far the oil on the ignition shelf and about the vaporizing ring is kept burning by the initial ignition means whether it be an electric igniter or a gas pilot flame, and the next and all important step is when the automatic control stops or cuts out the initial ignition means, and the burner must continue name propagation solely on the oil and air being supplied.

l 2,227,195 ordinarily m this type or burner embusuon' will continue if suilloient air is supplied, but it must be understood that with either a cold or a comparatively cool nre-chamber, andvparticular- 1y with a properly restricted supply of air, an excess amount of unvaporized oil is projected, as it does not properly vaporize and mix with the air, especially when the air supply is comparatively quiescent as in the present invention, and not forced into contact with the oil. Consequently an auxiliary air supply is desirable, otherwise the excess oil will smother the 4llame propagation.

This is adequately provided for in the present invention by means of the air admitted through the auxiliary supply tube 40, which is not closed until the nre-chamber is completely heated, at which time the thermostatically operated bimetal closes the valve over the tube, and combustion continues with a properly proportional supply of oil and air.

It has been .learned from experience that with the present type of burner, when suiilcient air is provided for starting a nre in a cold chamber, then after the parts become heated the excess air will cause noise, a yellow ame and soot; whereas with the automatic supply of extra air for starting purposes only, these objectionable features are eliminated.

When the burner is in normal running operation, it has been ascertained that the heating eiiiciency is exceptionally high, as the oil is most eiilcaciously vaporized once the vaporizing ring is heated, and the most eiective combustion occurs over the dome of the fire-chamber.

The means for admitting the 'air in the present invention keeps the fire-chamber filled with the proper proportion for combustion with the oil being supplied, and under such conditions there is no forced draft or blast combustion. I

The vaporizing ring does not get excessively hot, and an aluminum igniter shelf can actually be used without burning. Likewise the distributor head does not become excessively hot. but rather accumulates a covering of iine dust which may be scraped away and reveals the metal top in its original condition.

The quantity of air supplied is exceptionally small in comparison with standard practice, and the resultant ame in the lire-box is largely of the invisible Bunsen type with occasional purple, blue and orange streaks.

To sum up the invention, it carries the flame beyond the spinner or plate type to the circle or wall type, and beyond to the arched or dome type with a hollow or air center, and only sumcient side flame to effect eilcient vaporization.

I claim:

1. An oil burner comprising a lire-chamber having a primary air inlet opening, a damper adjustably limiting the primary air admitted to said inlet opening, a vertically mounted motordriven distributor head in said chamber appreciably above said primary air inlet opening and having radial discharge tubes for projecting globules of oil in a substantially horizontal plane, a vaporizing ring arranged in said chamber concentrically with said head and in the path'of the oil projected therefrom and a thermostatically controlled auxiliary secondary air inlet conduit independent of said primary ,air inlet and opening into said chamber adjacent said vaporizing ring.

2. An oil burner comprising a nre-chamber having a primary air inlet opening, a damper adjustably limiting the primary air admitted to said inlet opening, a vertically mounted motordriven oil distributor head in said chamber appreciably above said inlet opening, a vaporizing ring concentrically arranged some distance from said head and in the path of the oil projected therefrom, a shelf supported in front of said ring and onto which unignited oil globules will tall after impingement against said ring, means for igniting the oil on said shelf and means forV supplying supplemental secondary air to said chamber independently oi.' said primary air and adjacent said vaporizing ring for a. limited time -to assure sufilcient llame and resultant heat to initially' ignite and vaporize the oil impinglng against said ring.

REX E. MOULE.

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