US1699732A

US1699732A - Of san francisco

Info

Publication number: US1699732A
Authority: US
Publication date: 1929-01-22
Anticipated expiration: 1946-01-22

Description

Jan. 22, 1929.

C. H. BALMAT FURNACE Filed June 2, 1925 Jan. 22, 1929.

1,699,732 0. H. BALMAT I FURNACE Filed June 2, 1925 2 Sheets-Sheet 2 Patented Jan. 22, 1929.

' UNITED I STATES J PATENT OFFICE;

CECIL H. 'BALMAT, or sAN FRANCISCO, GALIFORNTA,ASSEGNOIQVBY miisNE Assren MENTS, T0 STANDARD OIL coMrANYoF CALIFORNIA, or SAN FRANCISCO, CALI- FORNIA, A CORPORATION OF DELAWARE.

summon.

Application filed June 2,

This invention relates to a furnace for burning fuel oils, espec ally heavy fuel 0118,.

and while the furnace may be adapted for it is necessary to effect a suitable atomization of the fuel, to provide the correct quantity of air, and to maintain the propertemperature during combustion. The burners which are used in industrial plants for burning heavy oils are'usually either of a type in which steam, or sometimes air, under high pressure is utilized to atomize the oil; or, of a type in which the oil is broken up by mechanical means, either by being forced to issue from a small orifice or from the periphery of a rapidly revolving, cup. In domestic installations, steam under high pressureis notavailable; neither is compressed air, and. furthermore, burners using these means for atomization are noisy in operation and require exact control, preferably by an expert. Burners using mechanical means for effecting the pulverizationv of the fuel arc, in general, not very flexible under domestic conditions-that is, they havespoor ability to change from a small to a large fire cflicientl Furthermore, they require con siderable cleaning. M Those burners which utilize pressure alone for the atomization of the oil require high pressure pumps and in small sizes, such as would be suitable for domestic use, the orifices are necessarily so small as to become very easily stopped up, One of the difiiculties in burning oil in a domestic furnace lies in the fact that the shape and proportions of the furnace or dinarily availablearesuch as to require a very short length of flame, that is, extremely rapid combustion; moreover, the usual. furnace will not hold the heat at low burning rates sufficiently to effect proper combustion. In order to burn heavy fuel oilssuccessfully in the usual domestic furnace, therefore, it is necessary to effect the most thorough atomizationof the fuel in order to bring the flame length into the practical limits ime posed by the space available. pointed out, this thorough necessitates the use of complicated means, V and, in general, is very difficultto effect in domestic installations, These difficulties obtain primarily because little orno attention As just atomization 192 5, SerialNo. 34,364.

has been given to the proper shape and d esign-of the furnace firebox audits relation to theburner.

H The general ob ect ofthis invent on is to which the requisite temperature conditions are always maintained, even for, the smallest produce a furnace of simple construction in flres, and operating in such a way that the gases during combustion pass through a rela tivelylong path; also to provide a construction in which the flame or gas during COlIlbLlStiOIliSfiflllSGd to reverberate Within thefirebox, at the same time providing means for protecting the .burner from direct impingement of the reverberating flame; also to provide means for producing a regenerating eifectwithin the firebox, by directing the reverberated. flame along the same path as the flame issuing from the burner;valsoto provide meansfor confining the flame more or less to theimmediatevicinity of the firebox; also to provide a furnace of relatively small volume constructed entirely of refrac-v tory material which becomes highly heated and radiatesor throwsback a large amount of heatto the fire; and bythis construction to permit the use of relatively simple means for atomization, or to increasemateriallyv the ciliciency and flexibility of burners utilizing more complicated means. 1

A further object of the invention is to provide a construction in which the fuel oilis sufficiently heated to enable it to flow freely to the burner tip, and to assist itsatomiza tion, but in which the fuel is sufliciently protected from the furnace heat to prevent its volatilization before itreaches-the tip oftlie burner. Q i

Further objects of the invention will appearhereinafter. a q

Theinvention consists in the novel parts and combination of parts, to be described hereinafter, all of which contribute to produce an efflcient furnace. l I

A preferred. embodiment of the invention. is described in the following specification, while the broad scope of the invention is pointed out in the appended claims.

In the drawings: j A Fig. l is a diagrammatic view showing in side elevation a furnace embodying my invention, the upper port-ion of, the furnace being broken away.

fire box, taken about on the line 22 of Fig. 1.

Fig. 3 is a cross section taken through the furnace above the fire box on the line 33 of Fig. 1;. i

Fig. 4 is a vertical section taken through the fire box on the line 4l4 of Fig. 3.

Fig. 5 is a vertical section at the side of the fire box wall and showing a modified embodiment for the face of this wall to 1ncrease the conduction of heat 1nto the furnace wall;

-Fig. 6 is a horizontal section through a portion of the fire box wall and showing another embodiment of the idea disclosed in an enlarged scale.

Fig. 7 is a vertical section through the wall of the fire box and showing a portion of the burner in section, the rest of the burner being "shown in elevation and the connection to it broken away. This view is upon Fig. 8 is a vertical section taken on the line 8-8 of Fig. 7 illustrating details of the locking means for holding the fuel pipe in any adjusted position.

Fig. 9 is a longitudinal section illustrating a modified embodiment of the burner nozzle.

"Fig. 10 is a front elevation of the burner shown in Fig. 9. r

Fig. 11 is a longitudinal section showing another embodiment of the burner.

1 Fig. 12 is a front elevation ofthe' burner shown in Fig. 11.

Fig. 13 is a plan of the tip of the fuel pipe shown in Fig. 7.

Fig; 14 is a side elevation of the tip shown in Fig. 13.

Fig. 15 is a horizontal section through the fuel pipe tip taken about on the line 1515 of Fig. 14.

.Thefurnace 1 which is illustrated. is of the upright type, with a fire box 2 at its lower end and a combustion chamber 3 above the fire box. Inapplying my invention to a furnace of this type, I provide means for admitting an. air blast and fuel at one side of the fire box, and I construct the fire box in such. a way as to effect a reverberation of the flame or gases during combustion in a substantially horizontal I plane so that they are made to flow back to provided with regenerator means adjacent the burner which also operates to assist in protectlng the burner from impingement of the flame.

' air nozzle 5.

In orderto accomplish this, I provide a burner 4 which operates as an air duct or This nozzle 5 is of relatively large diameter and carries within it a fuel pipe 6 which in the present instance is constructed-to carry a relatively heavy oil fuel. The oil pipe 6 is preferably located centrally in the air nozzle so that it is insulated by the air blast from the temperature in the fire box wall 7 in which the burner 4 is mounted; this burner is constructed so that although sufiicient heat reaches the pipe to enable the oil to flow freely in the coldest weather, at the same time it is sufliciently insulated due to the construction of the burner that the oil passing through the pipe will not become vdlatili'zed. The air nozzle 5 preferably has a tapered or conical tip 8, and the tip 9 of the fuel pipe preferably projects a fraction of an inch through the orifice of the air nozzle (see Fig. 7). The forward end of the oil pipe may be supportedin a cross bar 10 which passes diametrically across the air nozzle. The pipe 6, however, is adjustable through this arm or bar 10. The air blast is preferably furnished by a fan or blower 11 which may be driven by an electric motor 12. The air is preferablyat a relatively low pressure.

Any suitable means may be employed for controlling the flow. of the air blast to the burner, for example, a valve 13 may be provided which in the present instance is lo cated between the blower and the burner. By closing this valve more or less, the amount of air flowing to the burner may be nicely regulated. This valve may be of any desired type.

The fuel oil may be supplied through a flexible pipe 14: which admits the oil through a valve 15 at the back end of the fuel pipe 6. At its outer end, the fuel pipe is carried. in a bushing 16 which is screwed into the back of the air nozzle and suitable means may be provided for locking the fuel pipe and bushing in any adjusted position. For this purpose, the bushing 16 may have an extension or neck 17 at its inner end with a longitudinal groove 18 which may receive a set-screw 19 (see Fig. 8).

Referring again to the fire box 2., the wall opposite to the burner is provided with means, for example a rid go or abutment 22. extending in a vertical direction, which is located on the axis of the burner, and this ridge operates to divide the gases during combustion, or the flame, into two currents, as indicated by the arrows in Fig. 2; in other words, the inner end of the fire box is constructed with a grooved face 20 at each side which guides the flame back toward the front of the fire box.

I provide suitable means to prevent this flame from impinging on the burner, and this function is performed by regenerator means in the form of a tunnel 21 between two regenerator walls 23 disposed on opposite sides of the tunnel. Back of each wall 23 is a flue 24 through which thegases or flames pass; at a point near the nozzle, and on each side of the nozzle, the wall of the tire box is provided with curved guide faces 25 which bend the flame or gases during combustion toward the back of the furnace. In other Words, this end of the fire box is shaped so as to deflect the flame forwardly and over the burner so that it also assists the regenerator in protecting the burner from the flame.

When the furnace is in operation, of course the regenerator walls 23 become very highly heated, and if any drops of oil fail to be atomized sufficiently and fall upon the faces of these walls 23, they will be immediately ignited or will be taken up again by the current of gases passing these faces. The furnace is preferably provided with means operating to confine the gases during combustion more or less to the fire boxes. Any suitable means may be provided for this purpose, but in the present instance I merely provide the inner face of the furnace wall with a coping 26 which projects horizontally into the furnace chamber and divides the ire box from the combustion chamber 3 above it. This coping extends further out into the fire box at the end of the fire box which islocated near the burner, so that it extends over the regenerator walls 23 and assists in forming the return flues 24.

In starting up a furnace with a heavy fuel oil, it is sometimes necessary to provide special means for igniting the oil and warming up the burner. This may be accomplished if desired by throwing some oil-soaked waste into the furnace, or, if desired, a gas con nection 27 may be run into the back part of the furnace. If desired, the connection 27 may be used after starting the furnace for delivering an additional supplyof air, or other connections may be used at] other points in the furnace for admitting additional air for combustion. The tip 9 may have any form or construction desired, and steam, air, mechanicahor other means may be used to effect the desired atomization of the fuel; I prefer, however, to utilize a low pressure airblast for atomizing the fuel'a-nd to construct the tip so that it has the features illustrated in Figs. 13 to 15. This tip is produced by swaging out the end of the oil pipe to the shape of a fun-' nel and then flattening it to a fan-shaped outline. Between the two sides a narrow slot is left, andthis capillary space is kept intact during the remaining operations by any suitable means, but most conveniently by the insertion of a triangle of thin sheet metal, which iswithdrawn when the Work is finished. The tip is then rolled about a longitudinal axis so that, looking on the end,

the slot becomes circular in form. One of the sides thus is made into the inner wall or tongue 28, and the other becomes the outer wall and a cont-inuation of the pipe. By this operation, the points 29 of the flattened tip arerolled together over the tongue so. that they'meet as at the point 30, in' Fig. 13. In this way, directly over the tongue 28, an air duct 31 is formed through which the air blast flows as indicated by the arrow in Fig. 13; the effect'is to provide a narrow grooved throat 32 (see Fig. ,15) into which the oil will pass by capillary attraction. This-enables the tipto operate effectively although there may be a very small quantity of, oil arriving at the tip.

In order to increase theheat radiating surface of the furnace wall, I may provide the interior ofthe fire box with horizontal corrugations 33 (see Fig. 5) or I may provide it with corrugations 34 (see Fig. 6), vertically. The form of corrugations shown in Fig. 5 seems to be preferable,however, because it does not impede or produce eddy currcntsin-the flame as it passes-along'the side walls of the fire box; at the same time it would produce a very intimatecontact between the flame and the fire box wall, en-

abling the wall to absorb a very consider able quantity of the heat in the gases or flame. 1

Other types of fuel pipe tips or nozzles are illustrated in Figs. 9 to 12. In the form shown in Fig. 9, the end of the fuel duct or fuel pipe 35 is bent up and formed into an annular nozzle 36 into which a bushing 37 may be screwed from the rear. This bushing 37 carries an air duct 38. The bushing 37 is of slightly smaller diameter than the nozzle 36, so that a narrow annular space 39 is formed around the bushing which may, if it is small enough, exert capillary attraction on the oil. y

In the type of burneror oil pipe tip shown in Fig.11, the pipe 40 is drawn down into a tapered end orspear 41 which passes into the center of an air nozzle 42 to which it is connected. "A passage 43 leads from the interior of the spear into a conical annular space 44 around the nozzle I2, this space is formed by screwing on the nozzle 4 2 an outer nozzle 4510f conical form.

It isevident that in theoperation of this furnace, the construction of the fire box is such as to guide the flame or gases during combustion in a relatively long path within the fire box. At the sametime', a regenerator effect is produced, though the burner is protected from impingement of the flame.

,The fire-box, of course, may be constructed of fire clay, fire brick, or any other suitable take, and I do not wish to be limited in the practice of the invention, nor in the claims, to the particular embodiment set forth.

What I claim is 1. In a furnace for burning heavy oils, the combination of a fire-box, an air-duct mounted in the fire-box wall, a fuel-oil pipe extending longitudinally through the airduct and projecting at its inner end beyond the end of the air-duct, said air-duct being of relatively large diameter whereby the fuel pipe within the same is insulated from the high ten'iperaturei of the fire-box wall, and regcnerator means located in the fire-box adj acent the burner, said tire-box having means for effecting a reverberation of the gases during combustion past the regenerator means.

2. In a furnace for burning heavy oils, the combination of a fire-box, an air-duct mounted in the fire-box wall, a fuel-oil pipe extending longitudinally through the air-duct and projecting at its inner end beyond the end of the air-duct, said air-duct being of relatively large diameter whereby the fuel pipe within the same is insulated from the high temperature of the fire-box wall, and regenerator n'ieans located in the fire-box adjacent the burner, said fire-box having means for effecting a reverberation of the gases during combustion past the regenerator means, said fuel pipe being disposed substantially centrally within the air duct, whereby the vairblast surrounding the fuel pipe operates to cool, and insulate the same from the high temperature of the fire-box wall.

3. A furnace for burning heavy fuel oils having a burner constructed to operate with a low pressure air blast, and operating to atomize oil with the air blast and direct the same across the firebox of the furnace, a combustion chamber above the fire-bo ,sa-id tire-box having a ridge in its wall opposite the burner to divide the burning gases and effect a reverberation thereof by directing the same in currents passing along the face of the side walls of the furnace back toward the burner, said fire-box having means projecting in from the wall above the current of gases operating to confine the same within the fire-box, a regenerator device at each side of the nozzle in a position to become highly heated by the flame from the burner, and covered tunnels on the outer sides of the regenera-tor devices receiving the said currents of gases passing along the walls of the fire box, and means in the fire-box adjacent the burner for deflecting the currents passing through the tunnels forwardly past the burner and between the regenerator devices.

4. In a furnace, the combination of a firebox and a combustion chamber above the fire-box, a nozzle for admitting the fuel, a regencrator adjacent the nozzle with a regenerator-wall on each side of the nozzle and having a return flue on the outerside of each regenerator wall, means for admitting an air blast at the nozzle so as to direct the fuel between the regenerator walls, said firebox having means for effecting a reverberation of the gases during combustion rear- Wardly through the said fines and thereafter forwardly between the regenerator walls.

5. A fire box having means for effecting fire-box having a ridge in its wall opposite the burner to divide the burnin gases and effect a reverberation thereof by directing the same in two currents in the same hori zontal plane and passing along the face of the side walls of the furnace back toward the burner, said fire-box having means projecting in from the wall above the currents of gases operating to confine the same within the firebox, a regenerator device at each side of the nozzle in a posit-ion to becomehighly heated by the flame from the burner, and covered tunnels on the outer sides of the regenerator devices receiving the said currents of gases passing along the walls of the fire-box, and means in the fire-box adjacent the burner for deflecting the currents passing through the tunnels forwardly past the burner and between the regenerator devices.

7. A furnace for burning heavy fuel oils having a burner constructed to operate with a low pressure air-blast and operating to atomize oil with the air-blast and direct the same across the tire-box of the furnace, a combustion chamber above the fire-box said firebox having a regenerator wall on each side of the burner, disposed in a substantially vertical plane and extending longitudinally with the axis of the'burner, said fire-box having covered flues on the outer sides of the regenerator walls forming covered tunnels for directing the flame back toward the forward wall of the fire-box, the forward wall of the firebox having means on each side of the burner for de'liectingthe currents passing through the said fines, past the burner and between the regen-erator walls and toward the rear wall of the furnace.

8. In a furnace for burning heavy fuel oils, the combination of a burner constructed to operate with a low pressure air-blast and operating to atomize oil with the air-blast and direct it across the fire-box of the furnace, a combustion chamber above the fire-box, the back wall of the fire-box operating to divide the current of flame from Wall of the furnace along the vertical faces the burner into two currents in'the same horlzontal plane passing toward the front of its side Walls, a pair of regenerator Walls disposed in a substantially vertical plane one on each side of the burner and extending longitudinally with the axis of the burner, said fire-box having a covered flue on the outer side of each regenerator Wall forming a tunnel for guiding its corresponding current of flame back to the front wall of the fire-box, the said front Wall ofthe fire-box having means for deflecting the two revervberated currents of flame past the burner and between the said regenerator Walls.

Signed at San Francisco, Calif. this 21st day of May, 1925.

Y L CECIL H. BALMAT.