US2315482A

US2315482A - Hydrocarbon fuel burner

Info

Publication number: US2315482A
Application number: US386576A
Authority: US
Inventors: Fortis Oscar
Original assignee: JACK W HEARST
Current assignee: JACK W HEARST
Priority date: 1941-04-03
Filing date: 1941-04-03
Publication date: 1943-03-30
Anticipated expiration: 1960-03-30

Description

March 30,1943. I F TIS 2,315,482

HYDROCARBON FUEL BURNER Filed April 3, 1941 2 Sheets-Sheet. 2

Fla. 7

lNl ENTOR By OSCAR FORT/S A TTORNE V transformation.

Patented Mar. 30, 1943 IIYDROCARBON FUEL BURNER Oscar Fortis, Williston Park, N. Y., assignor to Jack W. Hearst, Chicago, Ill

Appiication April 3, 1941, Serial No. 336,576

1 Claim.

employs the light grades of hydrocarbon oil due Y to the Venturi tube type nozzle construction of the injection system which would be clogged or locked by capillary action if heavy hydrocarbon oils were used. The light oils are necessarily I deficient in heat energy per unit volume so that a greater amount of oil must be consumed to attain the required heat generation.

Another disadvantage of the present type of conventional burner is the reliance upon electrical power for propulsion, ignition and atomization of the oil in order to vaporize and fire the oil when brought to the state of efficient heat This dependence on electric power is fraught with difficulties due to power breakdown, particularly in the case of storms, where considerable hardship isexperienced in suburban or outlying districts; or loss of heat comfort due to motor or ignition failure. Furthermore the attendant components of the power system require constant supervision and maintenance which increase the total cost.

Another disadvantage of the heating system is the low efficiency of the conversion of the oil to heat energy in which great losses are occasioned by the formation of carbon in the flame due to the incomplete combustion of the oil spray resulting from insuificient breaking up of the oil globules, lack of temperature conditioning of the oil particles to realize the ultimate heat efficiency present therein, and intermittent operation of the system which results in taxing the furnace equipment at low temperature levels and during intense high temperature periods. These conditions account for the lack of even normal conversion efficiency and in most cases the loss due to improper conversion is considerable. This invention is intended to overcome all these difficulties and to obtain the highest efficiency in the simplest manner.

The primary object of the invention is to generate uniform heat in a combustion furnace.

Another object of the invention is to attain high efficiency in the conversion of heavy hydrocarbon oils to effect the greatest heat transmission per unit volume.

A further object of the invention is to produce the propulsion, atomization and ignition of the heavy hydrocarbon fuel without the employment of electric power.

Still another object is to overcome the capillary action of the oil in the injector system of this invention; and,

A final object of the invention is to facilitate the complete combustion of the oil particles so that carbon residue is eliminated thereby in creasing the over-all efficiency of the furnace.

In accordance with the general aspects of this invention, the burner is embodied in an auxiliary enclosure which comprises a top water or steam chamber and a lower insulating baffle compartment forming between them and surrounded thereby a primary heat conversion area or mixing chamber immediately adjacent an injector nozzle which projects toward the en closure from the front Wall thereof in line with the horizontal axis of the enclosure. A steam pipe extends from the water chamber to the nozzle and is arranged to be further heated intermediate the chamber and the nozzle to condition or superheat the steam so that it reaches the nozzle in a substantially dry state and at the desired pressure for creating a vacuum action in the nozzle. My invention provides a receptacle containing readily ignitable material provided with a wick arranged in cooperating relation to the primary heat conversion area and the nozzle so that the burner may be started and maintained in operation until the resultant cloud of the atomized oil is self-igniting in the mixing chamber and the furnace.

Another feature of the invention is concerned with the supply of secondary air in the furnace proper in order to maintain all parts of the pit at a uniform temperature whereby chilling of the oil mist is eliminated. In carrying forward this idea the secondary air is preheated before contact with the flame to prevent reduction in temperature of the flame and to increase the combustion of the stray atoms of oil in the mist which are recirculated to the flame and con sumed. The complete combustion of the mist insures the greatest efficiency from the oil fuel with no carbon formation so that the highest heat conversion is possible.

Another feature of the invention is the segregation of the intense flame from the nozzle outlet so that carbon formation at the nozzle is prevented. In this arrangement the flame under the pressure conditions of the dry steam is advanced in the mixing chamber and later in the furnace pit so that a dark space equivalent to a cathode dark space in a gaseous glow discharge is present immediately adjacent the nozzle outlet and consequent incomplete combustion is non-existent. This dark space further protects the nozzle from excessive heat conduction which might produce corrosive action at the nozzle outlet.

These and other numerous features and facilities are inherent in the construction of the burner of this invention and will be more clearly understood by reference to the following detailed description taken in connection with the accompanying drawings.

Fig. 1 is a side view in elevation of the burner assembly of this invention showing its adaptability in a conversion installation with parts of the casing and furnace broken away to illustrate details of the unit and the formation of the flames in the unit and furnace;

Fig. 2 is a side view of the unit with parts of the mixing chamber in cross-section;

Fig. 3 is a cross-sectional view in elevation of the unit taken on the line 3-3 of Fig. 2.

Fig. l illustrates a front view of the burner unit taken on line G--4 of Fig. 2 and shows the feed pipes connected to the injector nozzle.

Fig. 5 is an enlarged view, principally in crosssection, of the injector nozzle of this invention showing the relationship of the various elemental parts entering into the assembly thereof.

Fig. 6 is an end view of the nozzle outlet looking in a direction indicated by the line 6-6 of Fig. 5; and

Fig. '7 is an enlarged top view of a section of the oil feed assembly of the nozzle showing the relation of the oil admitting aperture and the piston regulation stem which controls the now of oil to the combustion chamber.

Referring to the drawings, and particularly to Figs. 1 and 2, this invention is disclosed in one aspect as a conversion installation for the ordinary furnace for a residence although the same principles of the invention may be incorporated, in the furnace as an integral part thereof. As shown in Fig. 1 a furnace housing it having a pit H leading to a front opening 12 in the casing l3 and provided with a heat-resistant fire brick b aille base l4 cooperates with a burner unit I5 embodying the main features of this invention.

The unit comprises an ignition chamber iii, a mixing chamber ll intermediate the ignition chamber and the furnace and an injector nozzle l8 directed into the entrance of the ignition chamber and arranged centrally along the longitudinal axis of the burner unit. The mixing chamber is surrounded by an enclosure formed of a hollow receptacle or jacket comprising an up per water reservoir or steam generator l9 having an arched inner wall 25! and an outer wall '2; l, the jacket forming substantially the greater portion of the mixing chamber ii, and a lower U-shaped bafile member 22 of refractory material, such as fire brickwhich abuts against the lower edges of the side walls of the reservoir, the baffle and reservoir being secured to a flange plate 23 which is fastened to the casing iii of the furnace so that the mixing chamber ll is in line with the opening IQ of the furnace. The reservoir I9 contains water 24 supplied through an inlet 25 connected to an elbow valve 26 secured to the upper right-hand corner of the reservoir and the level of the water is controlled automatically by a float mechanism 21.

The forward end of the jacket is closed by ignition housing 22 having a truncated prismatic outline with the larger open end adjacent the entrance to the mixing chamber H and the tapered end closed by a wall having a central anchamber I5.

erture 38 which forms an opening through which th nozzle l8 extends and permits the primary air to flow into the ignition and mixing chambers of the unit. The upper end of the ignition housing forms a superheating channel Si in which a steam supply pipe 32 is situated, the pipe being arranged at a downward angle extending from the inlet portion 33 projecting vertically in the reservoir It to a closed nipple 3d exterior to the housing 28. The lower end of the housing carries a removable pan 35 which is slidably connected to the housing by guiding strips at on opposite sides of the housing. The removable pan encloses a supply of readily combustible fuel 3?, such as kerosene, which is fed to a wick 33 mounted in the pan and exposed to the ignition The wick may be lighted through the projecting cup-like channel 39 in the front of the pan. The housing 28 is also provided with a swinging cover Ml which closes an inspection opening 4| in the side wall.

The injector nozzle I8 is supported with respect to the housing 28 solely by a U-shaped pipe connection 42 which extends from the side of the nipple 3 t downwardly to and parallel with the front wall 29 of the housing and terminates adjacent to the central opening 30 of the housing where it is coupled to the steam inlet port 33 of the nozzle it. In this position only the tip of the nozzle projects a short distance into the it,- nition chamber and is wholly suspended in the center of the opening 3%] with the greater portion of the nozzle projecting outwardly in a longitudinal direction from the housing.

The nozzle i8 which forms the primary controlling element of this invention whereby the many advantages and efficiencies derived from the practice of this invention may be realized is shown more clearly in Fig. 5. The nozzle includes a cylindrical outer casing or barrel i i having a tapered mouth portion or extension 45 and two threaded nipples or arms 46 and Q7 extending in opposite directions from the barrel and being offset with respect to each other on opposite sides of the barrel just beyond the tapered portion 45. The opposite end t3 of the barrel is internally threaded and the inner bore of the barrel is reamed to a smooth finish up to and including the annular seat =29 which is positioned intermediate the arms 36 and 47 and closer to the inlet port 43 of the arm 45;. The inner portion of the barrel 50 beginning at the seat and extending beyond the steam port it is reduced in diameter and the energy orifice 5i is tapered toward the open end of the mouth portion 45 of the nozzle so that the wall of the mouth portion increases in diameter to form a jet for the pressure feed of the superheated steam supplied to the inlet port 13.

An internal sleeve member 52 is concentrically mounted within the barrel 44 and is rigidly secured therein by a threaded portion 53 which coacts with the end 48 of the barrel, the major portion of the sleeve being the exact diameter of the bore of the barrel to form a substantial seal against the leakage of the oil. The sleeve member 52 is formed with an enlarged annular head 54 external to the rear end of the barrel and carries an indexing or graduated drum or dial 55 having indicia marked on tie circumference as shown in Fig. l. The forward end of the sleeve 52 beyond the seat 3% of the barrel is formed with a reduced diameter injector extension 56 which terminates in a plane of the tapered barrel mouth and forms, therewith an annular orifice 51 for supplying the high pressure steam to the ignition chamber.

The orifice 51 is of restricted area at the exit thereof to insure the generation of high pressure and uniform distribution of the steam on all sides of the injector extension 56. The sleeve 52 is also provided with a wide undercut gap or recess 58 on its external surface slightly behind the shoulder of the sleeve resting in the seat 49 so that the recess communicates with inlet port 59 in the arm 41 which is connected to an oil feed pipe 60 as shown in Fig. 4. This pipe is connected to a tank reservoir (not shown) whereby the oil is fed by gravity to the nozzle. If desired a small reservoir may be utilized for the gravity feed, said reservoir being connected to the main oil storage tank and being refilled when necessary by a suitable hand pump. This arrangement avoids any difficulties attendant with the use of electric power. On the other hand, since the small reservoir may have a capacity to accommodate the oil required for a day or more of operation, a small electric pump may be provided to replenish the auxiliary gravity feed reservoir automatically without the occurrence of any inconvenience due to intermittent power failure during severe storms.

The large gap 58 in the sleeve forms a flood chamber for the oil supplied to the nozzle and the outlet therefrom is an orifice 6| of tear-shape or ellipsoidal form. The shape of the orifice 6i and its relative position with respect to opposite ends of the gap 58 is shown in Fig. 7 in which the larger diameter of the orifice is adjacent the rear or main body of the sleeve while the smaller diameter or apex is adjacent the bevel 62 leading from the gap to the shoulder of the sleeve located in the seat 49. The gap or recess 58 is wholly segregated from the interior of the sleeve except through the orifice 6| so that the oil fuel held therein will flow uniformly to the mouth of the nozzle. Furthermore, the particular configuration of the orifice facilitates the accurate control of measured quantities of fuel to the ejector end of the nozzle to regulate the size of the flame from a mere pilot flame to the capacity of the furnace pit.

The interior of the sleeve 52 is provided with a bevel seat 63 substantially in alignment and coaxial with the shoulder of the sleeve. This seat then merges into a bore 64 extending to the end of the internal extension 55 which is the main fuel injector passageway for supplying oil to the flame. The diameters of the bore, the sleeve seat 63 and the interior of the sleeve are all greater than the largest effective diameter of the orifice 61 so that the latter offers the smallest diameter i or the oil flow.

A piston stem 65 extends with a push fit into the sleeve 52 and is provided with an inner ground end 66 which accurately fits the bevel seat 63. In this position the orifice BI is completely closed so that the oil is prevented from flowing to the mouth of the nozzle. The stem 65 is retracted from the sleeve 52 to regulate the degree of opening of the orifice by a knob or hand disc 61 rigidly fastened to an extension 68 projecting rearwardly from the indicating dial 55, the degree of retraction of the stem being indicated by the pointer 69 which cooperates with the graduations on the dial 55. The piston stem is secured in the sleeve 52 by a threaded portion 10 which turns in the internally threaded end of the sleeve adjacent the dial 55. If desired a labyrinth packing 1 I may be provided within the sleeve to further seal the stem from oil leakage.

In addition to the burner unit of this invention which is supplied with primary air for the mixing of the injected fuel for the furnace, a secondary air supply is furnished in the furnace proper, through an inlet valve 12 which may be regulated by a sliding cap 13 arranged in the lower front portion of the furnace housing l3. This valve communicates with a coil 14 embedded in the re fractory base 15 of the furnace pit II, the air in its passage through the coil being preheated by the absorbed heat of the refractory material of the base so that when the air enters the pit of the furnace and comes in contact with the flame to increase the oxygen content, it facilitates the chemical reaction and prevents chilling of the oil particles in the furnace.

The operation of the burner of this invention is initiated by igniting the saturated Wick 38 in the pan 35 through the recessed handle 39 and the flame produced thereby heats the water 24 in the steam jacket l9 to generate steam which enters the extension 33. The steam passes through the pipe 32 in the channel 3| where the steam is superheated to remove most of the water vapor and increase the pressure in its travel to the steam inlet port 43 of the nozzle 18. The dry steam enters the annular orifice 5| and in leaving the emerging end 51 of the nozzle produces a vacuum action adjacent the oil supply orifice 64. The regulation of the piston stem 65 permits the heavy oil fuel to flow through the orifice 6i and under the action of the annular steam jet, the oil is drawn out of the extension 55, propelled and diffused into a fine mist in the ignition chamber 15, the oil wick flam readily igniting the mist which produces a flame 16 shown in Fig. 1. It will be noted that the pressure of dry steam projects the flame into the mixing chamber l1, the tail of the fiame remaining in the ignition chamber to superheat the steam traveling therethrough and producing an unignited enveloping zone adjacent the nozzle.

As the flame develops due to the progressive generation of higher pressures at the steam jet, the flame is propelled to a position indicated by 11 in Fig. 1 in which the major portion of the flame is located in the furnace pit while the tail thereof together with the consequent radiation from the furnace flame maintains the mixing chamber and the ignition chamber at an elevated temperature to supply the generated and superheated steam to the nozzle for the propulsion of the hydrocarbon fuel.

While the invention has been disclosed in a specific embodiment, it is, of course, understood that various modifications and rearrangements of the component elements of the burner unit assembly may be made without departing from the scope of this invention as defined in the appended claim.

What is claimed is:

A liquid fuel burning furnace having a casing with a hollow interior, a refractory base, a coil embedded in said refractory base and leading on one end to said hollow interior, and an air inlet valve attached to and in communication with the other end of said coil and extending through said refractory base to the exterior thereof, said casing having in its front portion an open mouth, and a preheating unit comprising a base, a jacket contacting said base and arched to provide a mixing chamber therebetween, said mixing chamber having open rear and front portions, a flange plate attached to said base and said jacket, said flange plate attached to the casing of said furnace so that the open rear portion of the mixing chamher is in communication with the open mouth of the furnace, a forwardly converging front housing contacting said jacket and said base at. its larger rear portion, said front housing having therein an ignition and preheating chamber with open rear and front portions, said open rear portion of said ignition and preheating chamber communicating with said open front portion of said mixing chamber, said jacket having a steam f orm- Iii \ chamber, and ignition and preheating means within said ignition and preheating chamber.

OSCAR FORTIS.