US1825047A - Burner - Google Patents

Description

J. BUCHEL Sept. 29, 1931.

BURNER Filed Feb. 17, 1928 Patented Sept. 29, 1931 UNITED STATES PATENT' OFFICE JULES BUCHEL, OF NEW ORLEANS, LOUISIANA, ASSIG-NOR OF ONE-HALF TO THE ESTATE OF CHARLES LOUQUE, OF NEW ORLEANS, LOUISIANA BURNER Application led February 17, 1928. Serial No. 254,959.

The present invention relates to burners, such as those known as gas burners, and of a type similar to that known as Bunsen` burners.

Among the objects of the invention is to provide a novel burner having novel parts, and which will efficiently burn with the desired flame without any danger of extinguishment of the flame upon any variation of gas pressure, whether occurring slowly or suddenly, and without any flashing back of the flame or internal ignition of the combustible mixture, irrespective of the fluctuation in pressure of the gas, or wind blowing the flame, or heating ofthe burner body, or by reason of the proximity of any flame at any part-of the burner, such as the air inlet there- By the present invention, a blue flame is assure'd at al1 times under all conditions, except` that of completely shutting off of the fuel supply, to which the burner may be subjected. This burner absolutely will not backfire or flash back. In the usual burner not constructed as that of this invention, any mixture of fuel and air to obtain a blue flame combustion, is always attended -by facility in back-firing or flashing back. To reduce this danger, it has been the custom to feed the gas more or less undiluted, but the flame burns with a smoky result due to insufficient dilution and consequent dissociation ofy the. hydrocarbons. When the gas is diluted with air, oxygen,-nitrogen or other supporter or non-supporter of combustion, the effect is to decrease dissociation and so promote blueflame combustion. If air, or oxygen, or the like,A be used in excess to produce blue-flame combustion, which is usually the case, themixture becomes explosive with a high rate of flame propagation and this may, and often does, exceed the efflux velocity of the gas mixture from the orifice of the burner and backfiring is the result. To prevent this the mixture has been made so rich that the coefficient of flame propagation is zero. Such a mixture, however, cannot be burned by an ordinary burner, such as the Bunsen burner, Without producingr a yellow smoky ame.

The present invention, therefore, has

among its objects to wholly eliminate all of these disadvantages by providing a structure such that blue-flame combustion may be effected with a supply of air or oxygen which is so restricted that if the same mixture were fed to an ordinary burner, such as a Bunsen burner, it would produce a yellow smoky flame instead of a clear blue flame. Hence, a specific illustrative embodiment of this invention comprises a two stage expanding passage, such that the gas discharging from the gas orifice or nozzle expands more or less abruptly into the first stage or section of the passage where mixture is effected with air or other supporter of combustion. The air is admitted through a narrow or slot form of inlet passage located at the'juncture of the orifice discharge and the first stage 'passage section. This slot is preferably cut laterally through a side of the passage and transversely ofthe direction of flow of the gas or mixture, and also to intersect at the juncture mentioned. The floor or lower face of this slot is preferably even with the -outlet end ofthe gas orifice. The mixture then moves at a given velocity to the secnd stage passage section, which is of greater cross-sectional area than the first stage passage section, to the end that the mixture may more or less abruptly expand and while decreasing its flow velocity, produce eddies that effect a very thorough mixture of the air andI gas. The'more thorough .the mixture before ignition the smaller the amount of excess air or oxygen required to effect blue-flame combustion and this in turn makes for greater stabil'- ity and resistance to back-firing.

It has been found .by experiment with a properly proportioned burner that the reduction of excess air -besides conferring nonback-fire properties has the effect of increasing the efficiency of the burner to as much as 8% above that of the ordinary burner, such as the Bunsen. The increased efficiency is largely due to the reduction of excess air and a larger flame volume resulting from the expansion of the gases within the second stage tube, and also to some extent to a lower flame temperature. As the atmosphere contains about 80% of nitrogen, a lower flame ing excess air is that of a perfectly silent action; the more air admitted, the more noisy the burner iame would be.

Heretofore, to secure stable combustion,

it was necessary to eilux the mixture at a high velocity which resulted in giving too little time for complete and thorough mixture, an excess of air being accordingly required. In the present invention, the second stage passage section acts somewhat as a damping means, reducing the higher lvelocityA in the first stage to a slower one in the second, such that the kinetic energy is reduced in the ratio of 50 squared to 18 squared. Some of this energy is used toovercome the air resistance at the top end of the burner tube, but'the larger portion is dissipated in forming eddies within the second stage section, with the effect of producing a practically perfect mixture before it is exposed to combustion in the air at the outlet of the burner.

This effect is produced at all pressures of the gases, hence fluctuations in pressure do not change the stability of the device:` If the gas pressure drops, the air drawn in at the slot is proportionately reduced and vice versa. The damping effect of the second stage section is such that at high velocity of gasl How. the too high induction of air is prevented by reason of increased friction, whereas at low rates the resistance is reduced thus facilitating the induction of air at a time when the kinetic energy of the gas islow and has little propelling force. It also prevents dissipating action on the part of the stream of gas from the nozzle or orifice, which athigh rates of fiow may pierce the center of the mixture which is rich in the center, and thus passing through it for the length of the burner produces a mixture more or less rich in the center and less so at the circumference. The damping eii'ect will also produce a change in kinetic energy of the system as the gas mixture passes from the smaller to the larger tube. In the larger tube, the mixture loses some of its velocityenergy (kinetic) andV acquires pressureenergy (static) to overcome the air resistance at the orice of the tubewithout any danger of piercing. When a given burner is turned very low, the kinetic energy of the gas is very small and. it has very little propelling power, but, coincident therewith the greatly reduced velocity in the smaller tube likewise reduces the resistance due to eddies and that due to work done at the orifice of the larger or second stage tube. In a properly proportioned burner, the regulating'effeet is such that it will burn with a blue flame whetherv turned high or low, and it will have the same resistance to back-dashing through the range of capacity from O to 100%. Moreover, it has never been found possible to ignite the gas at the air orifice when another gas flame is made to impinge against the same; it hisses and splutters but refuses to ignite.

Other objects, capabilities, advantages and features are comprehended by the invention as will later appear and are inherently possessed thereby.

Referring to the drawings, Fig. 1 is a vertical longitudinal sectional view through a burner constructed in accordance with the invention; Fig. 2 is a top plan view of the device; Fig. 3 is a view in side elevation of a fragmentary part of the same; and Fig. 4 is a horizontal sectional view taken in a plane represented by line 4 4 in Fig. 1 of the drawings. Q

Referring now more in detail to the drawings, the embodiment selected to illustrate the invention is shown connected to a base 1 in the form of a tripod having a pair of short legs 2 and 3 and a long leg 4. The base is hollow to provide g'a passage 5 to which leads a tube 6 with which lmay be connected any suitable gas conductor, such as a rubber tube. To the upper end of the passage 5 is threadodlyconnected a coupling 7 which in turn is threadedly connected to the lower end of the burner tube or body 8. The lower end portion has a passage 9 leading to a gas oriiice or nozzle 10, the orifice 10 being of given cross sectional area or diameter when of tubular form. The outlet of the orifice leads into a first stage passage or mixing chamber 11 which is of greater cross sectional area than the orifice 10. The juncture -between the orilice 10 and the passage 11'is more or less ab- Yrupt having a connecting wall 12 which should be anywhere between 45 and 90, so that the gas as it issues from the orifice 10,

'may more or less abruptly expand in the chamber 11.

The chamber 11 in turn leads to a second' stage chamber or expanding passage section v 13', the juncture between the two being also abrupt and having a connecting surface 14 ranging anywhere between 45 and 90, so that the gas issuing from the passage 11 into the chamber 13 may more or less abruptly expand, the chamber 13 being of greater cross lio sectional area than the chamber 11. The secondstage passage 13 has an loutlet 15 and the upper end of the tube may be provided with a chamfer 16 or similar bevel to aid in the inward flow of the air olvsupporter of combustion to the flame at the opening 15. i f

For the purpose of supplyingair or other supporter to the gas issuing from the orifice 10, the tube is providedwith a laterally cut slot 17 which extends into the lower end of the passage 11 and adjacent to or proximate to the discharge end of the orifice 10, as clearnected passage sections,

-fuel used and other conditions.

ly shown upon the drawings. It is preferable that the bottom surface or floor 18 of this slot be even or level with the discharge end of the orifice 10 as clearly shown. It will also be noted that the innerv end of the slot intersects substantially centrally the lower end of the passage 11 just at the discharge end of the orifice 10. The ratios of the cross sectional areas of the first and second stage tubes may be varied in accordance with the As an example, although not being limited thereto, one of the forms are in the ratio of the area of the second stage tube varying from 2.5 to four times the area of the first stage tube. This may vary upon or in accordance with the smoothness of the inside surface of the tubes. The kinetic energy of the mixture flowing through the first stage is therefore about from 6.25 to sixteen times greater than it is in the second stage tube and the drop in kinetic energy is constant regardless of the rate of combustion. The burner flame cannot crawl down the burner tube becausethe mixture cannot burn within the tube and its flame propagation velocity is practically zero.

This two-stage burner is stabilized by having the air slot as narrow as possible and cutting it laterally through the side of the tube substantially half Way through the burner body as clearly shown upon the drawings. The amount of air admitted to the burner may be determined by the size of this slot and the slot may be varied according to the quality of the gas used. After once determining the exact proportions of these two passages and slots, the device is then fixed and is not adjustable. Any adjustment that might be made is made when first determining the sizes required for these passages. In special cases, the air slot may be made adjustable, if desired.

While I have herein described and upon the drawings shown an illustrative embodiment of the invention, it is to be understood that the latter is not limited thereto but may comprehend other constructions, arrange-` ments of parts, details and features without departing from the spirit thereof.

Having thus disclosed the invention, I claim:

1. A burner comprising a series of connected passage sections, each succeeding section being greater in cross-sectional area than that of the receding section, and a narrow air inlet at t e juncture of a pair of said sections.

2. A burner comprising a series `of coneach succeeding section being greater in cross-sectional area than that of the preceding section, the change of cross-sectional area at said junctures being abrupt, and a narrow air inlet at the juncture of a pair of said sections.

3. A burner comprising a series of connected passage sections, each succeeding section being greater in cross-sectional area than that of the preceding section, and a narrow air inlet at the juncture of a pair of said Sections, said inlet being in the form of aslot extending transversely through the side of the second section of the series and intersecting vthe juncture of. it and the first section of the series.

4. A burner comprising a gas discharging orifice, an elongated mixing chamber leading from the discharging end of said orifice, an air inlet extending through the side of said chamber and proximate to said discharging end of said orifice, and an elongated expansion chamber leading from'the discharge end of said mixing chamber.

5. A burner comprising agas discharging orifice, an elongated mixing chamber leading from the discharging end of said orifice, a narrow air inlet extending through the side of said chamber and proximate to said discharging end of said orifice, and an elongated expansion chamber leading from the discharge end of Said mixing chamber, said expansion chamber being ofgreater crossgectional area than that of said mixing chamlil) 6. A burner comprising a gas discharging;

orifice, an elongated mixing chamber leading from the discharging end of said orifice, an I air inlet extending through the side of said chamber and proximate t0 said discharging end of said orifice, an elongated expansionchamber leading from the discharge end of said mixing chamber, said expansion chamber being of greater cross-sectional area than that of said mixing chamber, and the crosssectional area of said mixing chamber being greater than that of said orifice.

7. A burner comprising a gas dischargingr orifice, a first stage chamber of larger crosssectional area than said orifice and joined at the discharge end of said orifice, a second stage chamber of larger cross-sectional'area than that of said first stage chamber and connected to the other end of said first stage chamber, and a'narrow air inlet means at the junction of said orifice and said first stage chamber.

8. A burner comprisng a gas discharging orifice, a first stage chamber of larger crosssectional area than said orifice and joined at the discharge end of said orifice, a second stage chamber oi larger cross-sectional area than that of said first stage chamber and connected to the other end of said first stage chamber and a slot form of air inlet extending laterally into said first stage chamber at the juncture thereof and said orifice.

9. A burner comprising a small passage for gas, a larger and elongated passage for receiving the gas from the small passage, and an air admitting slot at the juncture of said small and larger passages, the inner part of said slot intersecting the lar er passage proximate to the outlet end of sald small passage.

10. A burner comprising an elongated passage open at one end and having a gas orifice at the other end thereof, and an air admitting .slot at the juncture of vsaid orifice and said passage.

11. A burner com rising an elongated passage open'at one en and having a gas orlice at the other end thereof, and an airadmittin slot at the juncture of said orifice and sai passage, said slot being disposed transverse to the length of said passage.

12. A burner comprisin an elongated pas` sage open at one end and aving a gas orifice at the other end thereof, and an air admitting slot at the juncture of said oriice and sai passage, said slot having a floor even with the discharge end of said orifice.

13. A burner comprising an elongated passage open at one end having a gas orifice at the other end thereof, and an air admitting slot at the juncture of said orifice and said passage, said slot extending transversely through a side of'said passage.

14. A burner comprisin a tubular passage having a series of linear ores of increasing diameter toward the outlet of the passa e, and a narrow air admitting means at t e juncture of the first and second bores of the series.

15. A burner comprising a tubular passage having a series of linear bores of increasing I my name to this specification.

diameter toward the outlet of the assa e, and an air admitting slot arrange at t e juncture of the first and second bores of the series.

In Witness whereof, I hereunto subscribe JULES BUCHEL.

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