US2214670A - Apparatus for burning hydrocarbon oils - Google Patents

Description

vSept-510. 1940. J: ,GIGILMQRE ET AL- 2,214,670

APPARATUS FOR BURNING HYDR'CARBON OILS Fild April Q 1936'- 3 Shee's---Sheerl l @www 'se,s1o,194o. J.G.G,LMORE Em .2,214,670

APRARATUS FOR BURNING I'IYDROAQARBONv OILS Filed April 9, 1935 :s sheets-sheet 2 'r IIIIIIIII/llll/lll l y wm/ I o/ a e a o [www J. G'. GILMORE r-:T AL

APPARATUS FOR BURNING 'HYDROCARBON OI-LS sept. 10,1940; `12,214,670

Filed vApril 9, -1936 y 5 Sheets-Sheet 5 Patented Sept. 10,L 1940 PATENT oli-*FICE p 2,214,610' APPARATUS Fon BllItInING mnooAnBoN Jackson G. Gilmore and Milton DrHuston, Columbus, Ohio, assignors, by mesne assignments, yto

Columbus Metal Products, Inc.,

Columbus,

Ohio, a corporation of Ohio Application April 9, 193s, serial No. 73,504

a 2 claims.

This invention relates to an improved apparatus for burning normally liquid hydrocarbons for heat generating purposes, and has particular reference to oil burners of the hydroxylating type in which liquid hydrocarbons are vaporized or gasifed in a controlled atmosphere to subsequently effect flame-producing, high temperature combustion.

In the non-atomizing type of -oil burner wherein an intermediate hydroxylated mixture is formed, it is customary to provide an open-topped vessel in the bottom of which an oil level is autom-atically maintained. Primary bodies of air are admitted into such a vessel and combine with oil not highly combustible except by the addition of further supplies of air, the secondary air supplying suihcient oxygen to support active or visible combustion in a zone usually exterior of the vessel. Due to the fact that active flame-producing combustion takes place above the yaporizing and mixing vessel, it frequently happens that an insufficient quantity of heat is applied to the oil body maintained in the bottom of the vessel to 25 effect the required heating thereof to temperatures sufficiently high to'liberate the gases and vapors in uniformly maintained quantities to promote evenly and uniformly maintained combustion rates at all stages of operation of the burner mechanism.

ent invention to maintain efficient, continuous and steady combustion in a hydroxyl-ating type of burner by producing Within the confines of an open-topped mixing vessel, and immediately above the oil level in the bottom thereof, an initial visible flame combustion rzone of limited capacity, whereby through the provision of this internal combustion zone a sufficient amount of additional heat will be developed to insure the desired vaporization and gasification of the liquid fuel, the formation of an improved hydroxylated mixture and efficient high temperature combustion of said mixture when additional quantities of secondary air are merged therewith.

A further object of the invention resides in providing the mixing vessel of a hydroxylating oil burner with a plurality of small apertures penetrating the walls of the vessel immediately above ,50 the body of oil normally contained in the bottom A55 vessel at a retarded rate of flow, lmay combine vapors or gases, producing a mixture which is Accordingly, it is a primary object of the preswith a sumcient but minor portion of the total oil vapor or oil gas, released from the body of oil, to produce localized resultant mixtures which will Iburn within the retort vessel with a non-luminous substantially blue flame, producing a sufficient quantity of added heat within the confines of the vessel to vaporize or gasify the oil, increase the temperature of the hydroxylated mixture and maintain a uniformity of operation and steadinessof combustion rates of e. greatly improved 'character over previous burners of this type.

It is another object of the invention to provide for internal' flame generating combustion within the retort vessel of the hydroxylating burner so that it is possible to burn efficiently and effectively for sustained periods of operation and without carbon or coke formation of an obstructing character, and to utilize lower grades of fuel oil than has been employed heretofore in such burners, thereby providing for more economical operation from the standpoint of fuel costs.

It is another object of the invention to provide oil burner mechanism comprising a dish-like vessel for maintaining a body of oil, a cone being mounted on and above said vessel and tapering upwardly therefrom, the said cone being provided with restricted openings for the admission of air, walls being provided around the cone in spaced relation therewith to form an annular air chamber, and means being provided for supplying air to the annular chamber, so that air so supplied will pass forcibly through the restricted openings of the cone and directed towards the body of oil maintained in the dish-like vessel.

For a further understanding of the invention, reference is to be had to the following description and the accompanying drawings, wherein:

Fig. .1 is a view in side elevation of oil burning apparatus constructed in accordance with the features of the present invention Fig. 2 is a top plan view, partly in horizontal section, the plane of the figure being indicated by the line II--II of Fig. 1;

Fig. 3 is a vertical transverse sectional view taken through the burner vessel on the plane disclosed by the line III-Ill of Fig. 1; l

Fig. 4 is a horizontal sectional View on the line IV-IV of Fig. 1; j

Fig. 5 is'a detail vertical sectional view taken through adjoining portions of the burner vessel on an enlarged scale, and disclosing more particularly themeans for producing initial combustion within` theburner vessel; y I

Fig. 6 is a diagrammatic vertical viewin cross section taken through the mixing vessel and illustrating paths of gas travel;

Fig. 7 is a vertical sectional view through a modified form of mixing vessel;

Fig, 8 is an enlarged sectional view on the line VIII- VIII of Figg?.

In order to understand the principles of combustion involved in the present invention, it is deemed advisable at the outset to review a widely accepted theory of combustion and clearly define the difference between combustion and ame. Technically speaking, combustion takes place when oxygen unites with hydrogen, VcarbonV or any other element and gives oil heat in the process. This would include such invisible reactions as the formation of OH and the nearly invisible complete combustion of hydrogen and oxygen to water vapor. Before proceeding, it

' will be well to define the meaning of the word conditions but is often a very useful way to ob- A serve combustion. It should not be confused, however, with the broad mechanism of com- 'bustion.

Hydroxylation consists in combining oxygen with oiland gas or gas in an atmosphere rich in hydrocarbons and is a step -in low temperature combustion. As used hereinafter, the term hydroxylation refers to the step of introducing regulated and limited quantities of oxygen into admixture with oil vapors or oil gases in quantities insuiiicient to support high temperature or ame producing visually observable combustion.

Hydroxylating burners are well known in the `industry and while they may vary considerably in 'structural detail, they usually comprise a vessel capable of receiving a body of liquid oil in thev bottom thereof and having a restricted vapor outlet in their tops, a plurality of air admitting apertures being provided in the side walls of the vessel to regulate the admittance of air into the confines of the vessel for producing the hydroxylating stage of operation. Such burners may be found in the prior patents to Breese, 1,702,929, Feb. 19, 1929 and Frame, 1,924,092, Aug. 29, 1933.

In the accompanying drawings, certain specific types of hydroxylating burners have been disclosed, since these types have been used effectively with the present invention incorporated therein, although it will be appreciated that the invention is much Wider in its general application. In the form of the invention disclosed in Figs. 1 to 5, the numeral I designates the hydroxylating burner vessel which, in the present instance, is formed to comprise a substantially bowl-shaped bottom section 2 and an inverted, funnel-shaped upper VVsection 3. 'Ihe upper portion of the bottom section 2, as shown in Fig. 5, terminates in an outwardly directed, horizontally disposed, annular flange '4 which acts as a seat for the reception of a circular gasket ring 5 upon'which thefunnel-shaped upper section 3 rests. Preferably, the section 3 is surrounded by a hood ifs o'fmanifold 6, spa'cedfrom the outersurfaces of the upper section 3 to produce an annular air-receiving chamber 1. This chamber is in communication with a pipe orconduit 8 leading to a motor-driven blower or fan 9, by which air under super-atmospheric pressure may be introduced into the chamber 'I and thence, by way of the rows of spaced apertures I-Il, into the interior of the burner vessel.

The bottom section 2 has arranged axially therein an oil inlet connection I I, supported by a swinging bail I2 connected with a casing I6 and adjustably held by a hand operated screw I3 threaded in the bottom of thelbail and engaging with the under side of the connection II. Said connection also unites with an oil supply pipe I4 leading to any well-known type of thermostatically controlled valvel mechanism I5, by which the ow of oil to the bottom of the burner vessel is regulated and a desired level of oil maintained withinthe concaved bottom of said vessel. Such controls are of standard design and do not per se form a part of the present invention but one form thereof will be hereinafter'described.

The casing I6 vsurrounds the burner vessel in substantially spaced relation therefrom and is provided with securing anges I'I by which the casing may be joined with the bottom plate I8 of a jacket I9 employed to surround a watercontaining tank 20 which the burner is adapted to heat, although in other aspects, the' burner mechanism may be employed for the development of heat generally, regardless of any specic use to which it may be placed.

The bottom of the casing 'I6 is openas at I6a to permit of the ow of air under atmospheric pressure into the compartment 2| formed between the casing and the vessel I. Above the hood or manifold 6, the conical walls of the upper section 3 are provided with spaced rows of apertures 22 so that air under atmospheric pressure may passthrough the apertures 22 and into the interior of the vessel to form the fuel mixture. Arising from the top of the casing I6 is a tube 23, which carries at its upper and outer end adepending apertured cone 24, which is arranged above and in vertical registration with the reduced outlet 25 of the top section 3 `of the burner vessel, the said cone 24 being provided with air distributing openings 26, providing for the issuance of air therefrom either under atmospheric or super-atmospheric pressures.

In the operation of a burner of this type, active visible combustion takes place within the top of the vessel in the immediate region of the outlet 25 or when operated at high capacity immediately above the vessel I and its outlet 25. The heat of such combustion is radiated on or conducted through the walls' of the vessel to the body of oil contained in the bottom section 2, causing the liberation of oil vapors or gases from the upper surface of this body of oil. Controlled or regulated amounts of oxygen are then admixed with the oil vapors or gases by reason of the air entering the vessel through the apertures I 0 and 22 producing an intermediate or hydroxylated mixture which passes upwardly and outwardly of the vessel where additional quantities of air are combined therewith so that active or flame combustion takes place, as set forth in our prior application, Serial No. 9,249.

We have found, in the operation of burner apparatus of vthis type, that greatly improved results can be obtained by providing for carefully regulated llame combustion within the burner vessel preferably adjacent the horizontal plane formed by the union of the bottom and top sections 2 and 3 respectively of said vessel. It is obvious that such initial flame combustion must be carefully regulated and controlled in order to apply the proper amount of heat to the oil pool in the bottom of the vessel' to cause the desired liberati-on of vapor or gas therefrom, to elevate the temperature of the intermediate mixture and to otherwise maintain eifective thermal regulation within the vessel, but without cracking the oil and causing its molecular decomposition with resulting carbon and coke formation. The rate of such internal active combustion within the burner vessel must be so controlled as to provide for the desired hydroxylation of the released oil vapors or gases with the primary and secondary bodies of air entering the vessel through the apertures I0 and 22 respectively without premature flame combustion of such a hydroxylated mixture 'so that the final hydroxylated mixture may be delivered through the outlet of the vessel and there admixed with sufficient quantities of air, obtained from` the distributing cone 24 and atmospheric oxygen, to support final combustion. Further, to provide internal flame combustion Within the burner vessel permitting of the use of relatively low grades of liquid fuels, and, finally, a type of internal combustion which will not form soot or carbon on the internal surfaces of said burner vessel.

These ends are definitely achieved through the provision of small diametered ports 21 and 28. The ports 21 are formed in the joined annular flanges 29 provided on the lower portions of the hood or manifold 6 and the top section 3 of the burner vessel, the said flanges being seated on and arranged over the gasket 5. Due to the inwardly bent crimped end 30 of the flange provided on the manifold 6, the lower ends of the ports 21 and 28 are disposed above the top surfacef the gasket 5, so that said gasket acts as a baille interrupting the inflow of air 'through the ports 21 and 28 and into the interior of the burner vessel, reducing the velocity of such air, and causing it to slowly enter the interior of said vessel so that it may be combined with bodies of oil vapor or oil or soot deposit readily takes place on the internal walls of the vessel which interferes with desired operation. However, by baflling the inflow of air through the ports 21 and 28 and into the vessel, the desired non-luminous combustion can take place with highly beneficial results in improving the operation of oil burners of the type under consideration. y

The volume of air entering the interior of the mixing vessel through the ports 21 and 28 for flame combustion is quite critical. Without limiting ourselves but only by Way of example of a satisfactorily operating construction, we have found that in a burner vessel wherein the outside diameter of the flange 29 of the conical top section measures approximately six inches, and the inside dia-meter, flve and one-quarter inches, best results have been obtained with the use of forty lof the 'circumferentially spaced openings, indicated at 21. Each of these openings is made by drill having a diameter of .0465 inch. The openings indicated at 28 are preferably ilve in number, suitably spaced circumferentially and are each produced by means of a No, 66 drill so that each of the openings 28 will possess a diameter of .033 inch. T he first row of openings above the flange 29 for the admittance of air from the hood or manifold into the hydroxylating zone consists of twenty openings, ten of which are produced by a No. 54 drill, each having a diameter of .055 inch, and the remaining ten with a No./56 drill, each having a diameter of .0465 inch, Certain of the openings in the bottom row of openings, indicated by the numeral I0, have their axes tipped downwardly relative to the plane of the conical side Walls, so that air entering the vessel by way of the same will be directed downwardly toward the bottom of the vessel to a greater extent than the openings in the superposed rows, which have their axes approximately perpendicular to the plane of the side wall.

As shown in Fig. 6, the row of openings I0a immediately above the lowermost row of openings I0, consists of ten circumferentially spaced openings produced by a No. 54 drill, each opening having a diameter of .055 inch. When the burner is operating at peak capacity, air under pressure enters the mixing vessel by way of the rows of openings I0 and I0a. Under low-fire operation, the air entering the vessel by way of the openings I0 and Illa is approximately at atmospheric pressure.

By reference to Fig. 6, it will be noted that the openings, 22, 22a and 22h, are arranged above the hood or manifold 6 so that air entering the vessel by way of these openings is under approximately atmospheric pressure on both low-stage and high-stage operation. The flrst row of openings 22 contains ten openings, each produced by a No. 54 drill and having a diameter of .055 inch. Similarly, the row of openings 22a comprises ten relatively spaced openings, each produced by a No. 54 drill and having a diameter of .055 inch. The uppermost row of openings 20h comprises thirty circumferentially spaced openings, each produced by a No. 54 drill and having a diameter of .055 inch.

It is thought by reason of the direction of flow of the air entering into the composition of the hydroxylated mixture, that sluggishly moving bodies of oil gas or vapor, probably in the form of eddy currents, unite with the slowly moving streams of air entering the vessel by way of the ports 21 `and 28 so that flame creating combustible mixtures are produced. These flames are of a ring-like character and have been observed at times to extend at local intervals inwardly of the burner vessel from the perimeter to the vertical axis thereof in the form of jets or fingers, and are -of a blue, substantially non-luminous color. The oil gas entering into the composition of this initial visible combustion is but a minor fraction of the total quantity of oil gas or vapor liberated from the body of oil in the bottom of the burner. Most of the oil vapor or gas passes upwardly into low temperature combinationiiwith the air entering by way of the ports I0 and 22 without being actively burned.

This initial active combustion is considered to be beneficial in several different respects, rst, it produces a zone of localized heat immediately over the pool of oil in the bottom of the vessel so that the latter is not so fully dependent', as heretofore, upon heat radiated from the zone of high temperature combustion above the vessel, or

upon the temperature of the walls of the burner vessel, which have acted to conduct heat from the zone of high temperature combustion to the oil pool. Secondly, since in a hydroxylating burner, continuous operation is taking place. the element of time is of'high importance.

The hydroxylated mixture formed within the confines of the vessel is a low temperature reaction and moreover is a reaction of the type which can be -accelerated by increased temperatures. Therefore, the formation of a more eflicient hydroxylated mixture is possible with the step of internal combustion within the mixing vessel than has been possible heretofore. Again, the internal operation of the mixing vessel, through the inclusion of the active combustion zone, is rendered independent to a greater extent of exterior temperature conditions and the burner as a whole less affected by the volume and size of draft factors in the combustion chamber or zone in which the vessel is situated.

In the-form of the invention disclosed in Figs. 7 and 8, a mixing vessel is indicated generally by the numeral 35, the same comprising a sheet metal base section 36 and a top section 31. The top section is of smaller diameter than the base section and its lower end lits within the open upper end of the base section, and is suitably secured thereto, the lower end of the section 31 being provided with an inwardly offset, annular and depending baiile 38, which is spaced from the inner surfaces of the vertically disposed rim 39 of the bottom section 36. The rim 39 is provided in registration with the baiile 38 with a plurality of small ports o1' apertures 40, s'o that limited quantities of air may enter the vessel by way of the openings 40 in substantially the same manner and for the same purpose as air is admitted through the ports 21 and 28 in the previously described form of our invention. These ports admit a sufficient inflow of air under low velocity int-o the interior of the mixing vessel to produce a zone of limited visible combustion above the body of oil normally maintained in the bottom of the base section 36.

The top section 31 is formed with an outlet 4| of reduced diameter asa compared with the internal diameter of the mixing vessel. Rows ofVV inwardly directed apertures 42 and 43 for admitting primary and secondary bodies of air, respectively, are formed in the side walls of the mixing vessel in horizontal planes above that of the active combustion zone, whereby to provide for hydroxylation.

Surrounding the casing 35 in spaced concentric relationship therewith is an outer casing 35a, having an open bottom 35h. The casing 35a corresponds in function to the casing 16 disclosed in Fig. 3 and provides for the cooling of the bottom 36 of the burner vessel and the introduction of primary and secondary air into the interior of said burner vessel through the ports 40, '42 and 43.

The present invention produces oil burner means of the hydroxylating type possessing a very wide combustion range and from which is omitted the ordinary pilot, used in prior burners to maintain continued operation between periods of maximum combustion. In the ordinary automatically controlled oil burner of the hydroxylating type between intervals of high-stage operation, that is, when the burner is ineffective, it is a common practice to utilize gas pilot flames,

electrical ignition devices or a small yellow burning ilame of hydrocarbon oil.

In contrast with such prior burners, the present invention provides for a very broad combustion range so that when the heat demand is negligible, the burner may be turned down and yet will burn efficiently, producing blue flames with hydroxylated mixtures and non-smoking combustion. As the heat demand increases, the oil and air supply to the burner is proportionately increased without varying the fundamental character of hydroxylating combustion. Ordinarily, the burner operates on what may be termed high-stage and low-stage cycles of operation. At high-stage, the amount of oil delivered to the burner for combustion may be ten or moreV times the amount supplied for low-stageop eration, thus producing what is known in the art as a ten to one turn-down ratio. When heat demand is created, the thermostatically controlled mechanism I5 opens the fuel control valve to increase the quality of oil suppliedl to the burner and at the sa'ne time energizes the motor employed for driving the fan 9, increasing the volume and velocity of the primary air entering the burner in accordance with the increased oil supply. During suchhigh stage operation, the primary air is supplied under pressure to the burner by way of the ports Ill, Illa and 28, increasing the size and temperature of the blue ame combustion over the oil pool and the amount of primary air available for producing the hydroxylated mixture, the latter, in such high stage operation, being subsequently burned exterior of the vessel in a luminous yellow flame. Air entering the mixing vessel under fan pressure through the orifices I9 andl Illa establishes an upwardly moving draft in the mixing vessel. Since the openings or orifices l 0 and Illa are disposed ina plane above the orifices 21 or above the plane of admittance of the restricted amount ofvair which enters the vessel through the openings 21, suction forces are produced facilitating the oW of air through the openings 21 and into the vessel. This is likewise true of the ports 22, 22a and 22h wherein, due to draft conditions set up within the mixing vessel, induced air flow takes place through said ports from the cham- -ber 2|. y

When the heat demand is satisfied, the operation of the motor driven fan is discontinued and the oil supply diminished by the automatic operation of the thermostatically controlled means I5. During such low stage operation, complete hydroxylation takes place as in the high stage,

with a substantially complete absence of smoke,-

soot and .carbon formation, but without the presence of the yellow external luminous llame. During such low stage operation, in view of the fact that smaller amounts o-f air are supplied to the interior of the vessel, blue flames or jets may be observed issuing at intervals from the openings I0, |0a, 22, 22a, 22h, 21 and 28 and with but a negligible amount of yellow flame combustion. The combustion produced therefore is complete at all stages of combustion, whether high or low, and no independent pilot llame is necessary to maintain continuity of operation. Y

'Ihe internal llame combustion ai'orded by the ports 21 and 28 is not employed merely to increase the temperature of the 'shallow pool of oil in the bottom of the vessel but to improve generally the operating characteristics of the burner. For instance, if external fheat should be applied to the bottom of the vessel to raise the temperature of the oil therein to the temperature which it attains by the use of the primary internal flame combustion, the final combustion results are greatly inferior to those obtained with the use of such internal combustion with respect to capaclty, temperature and freedom from smoke and carbon formation, thusv indicating the benecial character which such internal combustion apparently exercises in improving-and accelerating the hydroxylating reactions within the vessel.

The present invention, therefore, provides an extremely flexible oil burner ofthe hydroxylating 'type which operates efficiently throughout a wide combustion range and 'in this .respect differs materially fromprior burners of an analogius type but which are limited by their construction and operating laws to substantially a single high temperature combustion range.

What is claimed is:

1. In oilfburning apparatus, a burner vessel comprising a bowl-shaped base section and a separate conical upper section, means for maintaining a body of hydrocarbon oil within said bottom section, a hood surrounding said top section, means for introducing air under variable pressure into said hood,A restricted inlets providing for the inflow of air from said hood into said Vessel, restricted inlets arranged in said top .section above said hood and providing for the inow of air into said '.esselunder constant atmospheric pressures, and means formed in connection with the union between the bottom and top sections of said burner vessel and said hood to admit of restricted inflow of air into said ves. sel below said inlets in suflicient quantities to combine with but a minor portlononly of the oil gas and vapor released from said body of oil to provide a zone of limited active combustion.

2. In oil burning apparatus, a vessel comprising separable upper and lower sections, said upper section comprising a frusto-conical body having a restricted outlet opening at its top and a laterally directed, horizontally disposed seating ilange at the botto'm thereof, said lower section comprisinga cup-shaped body, including a closed bottom. an upwardly directed annular side wall and an outwardly and horizontally directed ange providing a seat for the ange of said upper section, means entering the bottom of said lower section for introducing regulable quantities of oil into said vessel for vaporization purposes', said upper section having formed in the Walls thereof spaced sets of restricted apertures, the lower of said sets lof apertures serving to admit of the iniiow of air into said Vessel, the intermediate rows of apertures admitting of the inowof primary carbureting air into said vessel for admixture with the oil vapors therein, and the upper rows of apertures admitting of the'inflow of both primary and secondary bodies of carbureting and combustion producing air into said vessel, a casing surrounding said vessel and spaced from the side walls thereofsaid casing having an open bottom anda closed top which provide for the passage4 of air across the bottom of the lowery section of said vessel and the delivery of air into the interior of said Vessel through the upper rows of apertures formed therein, a hood surrounding the upper section of said vessel, and means for delivering air to said hood under variable rates of iow for passage into said vessel through the primary rows of apertures.

JACKSON G. GEMORE. MJLTON D. HUSTON.

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