Title:
FUEL BURNER
United States Patent 3771727


Abstract:
A fuel burner for the combustion of a ternary emulsion consisting of a liquid fuel, a vapor or a gas and a liquid has a main body connected to a tubular duct for the admission of a liquid fuel into an mulsion chamber, the chamber being closed by a nozzle in which is engaged a movable regulating needle forming part of an axial operating rod. An outer casing which surrounds the body defines a separate admission zone for the vapor or the gas and a liquid, a communication being established beween the zone and the emuslion chamber through passageways arranged in spaced relation within the body about the axis of the operating rod.



Inventors:
ROBIC G
Application Number:
05/257389
Publication Date:
11/13/1973
Filing Date:
05/26/1972
Assignee:
ELF UNION SA,FR
Primary Class:
International Classes:
F23D11/10; F23D11/16; (IPC1-7): B05B7/12
Field of Search:
239/407,417.3
View Patent Images:
US Patent References:
1837861Spray appliance1931-12-22Green et al.
1779849Atomizing and spraying device1930-10-28Lusk
1767462Nozzle1930-06-24Lammert et al.



Primary Examiner:
King, Lloyd L.
Claims:
What we claim is

1. A fuel burner for the combustion of a ternary emulsion of a liquid fuel, a vapor or a gas and a liquid, said burner comprising a mainbody connected to a tubular duct for the admission of a liquid fuel and opening in a chamber in which the emulsion is produced, said chamber being closed opposite to said body by a nozzle, a central orifice in said nozzle, a movable regulating needle in said orifice, an axial operating rod secured to said needle, an outer casing surrounding said body and defining a separate admission zone for the vapor or the gas and the liquid, a communication between said admission zone and said chamber through longitudinal passageways arranged inspaced relation within said main body about the axis of said operating rod, said outer casing having a single duct for the admission of the gas or the vapor and the liquid which are intimately mixed before entering said emulsion chamber through said longitudinal passageways of said main body.

2. A A fuel burner for the combustion of a ternary emulsion of a liquid fuel, a vapor or a gas and a liquid, said burner comprising a main body connected to a tubular duct for the admission of a liquid fuel and opening in a chamber in which the emulsion is produced, said chamber being closed opposite to said body by a nozzle, a central orifice in said nozzle, a movable regulating needle in said orifice, an axial operating rod secured to said needle, an outer casing surrounding said body and defining a separate admission zone for the vapor or the gas and the liquid, a communication between said admission zone and said chamber through longitudinal passageways arranged in spaced relation within said main body about the axis of said operating rod, said outer casing having a duct for the admission of gas or vapor alone and at least one separate internal coil in said casing for the liquid, the mixing of the gas or of the vapor and the liquid with the liquid fuel occurring directly within said emulsion chamber.

Description:
This invention relates to an improvement made in fuel burners, especially with a view to improving their energy yield while enabling them to develop heat outputs which are higher than in known solutions of the prior art without entailing any proportional increase in their size and therefore in their weight, thereby achieving a corresponding reduction in cost of machining of components and limiting the overall cost price of the installation.

Consideration has already been given to the construction of burners so designed as to permit the production, within the actual burner nozzle, of a ternary emulsion consisting of an oxidizing or carburizing vapor or gas (which is usually air) with or without entrainment of solid particles, an additional liquid consisting of pure water or water containing soluble elements capable of reacting with certain combustion products which are formed and finally a liquid fuel, in particular a hydrocarbon in the pure state or in a mixture such as fuel oil or a residual effluent of refining. To this end, these burners usually comprise a main body, a distributor which delivers the liquid fuel to be burned into the burner nozzle and an operating rod which controls simultaneously the admission of the fuel and of the two other constituents of the ternary emulsion, said rod being so designed as to terminate in a movable needle which engages through the burner nozzle, wherein the liquid fuel is fed by the distributor into the burner nozzle through longitudinal and then radial grooves which open into an emulsion chamber extending around the control needle, the oxidizing or carburizing gas being admitted into the emulsion chamber through tangential slits which are formed in the main body and which also provide a communication with grooves for the admission of an additional liquid constituting the third phase of the emulsion.

The formation of the ternary emulsion at the instant which immediately precedes its combustion, that is to say in the actual burner nozzle, produces remarkable advantages, in particular by virtue of the fact that its constituents do not have the possibility of separating and the ignited mixture remains wholly homogeneous. Moreover, the direct admission of the three fluids of the emulsion into a chamber which is traversed by a movable needle having a predetermined profile and joined to an axial operating rod makes it possible by means of a single regulating action to modify both the delivery and overall composition of the emulsion.

The present invention relates to an improvement made in burners of the aforementioned type which, while retaining the general principle of design and operation of these latter, considerably increases both their performances and their efficiency.

To this end, the burner which is contemplated and comprises a main body connected to a tubular duct provided for the admission of a liquid fuel and having its opening within a chamber in which is produced an emulsion of said fuel with a gas or a vapor and a liquid, said chamber being closed opposite to the body by means of a nozzle pierced by a central orifice in which is engaged a movable regulating needle fixed at the end of an axial operating rod, is characterized in that it comprises an outer casing surrounding the body and defining a separate admission zone for the vapor or the gas and the liquid, a communication being established between said admission zone and the nozzle chamber through longitudinal passageways arranged in spaced relation within the main body about the axis of the operating rod.

By making provision for a separate zone of the emulsion chamber into which are admitted, prior to mixing with the liquid fuel itself, the two other constituents of the emulsion, namely a vapor or a gas which is preferably either oxidizing or carburizing, and the liquid which is usually water, it is possible in particular to cool the burner body to a considerable extent while reheating these constituents prior to mixing with the liquid fuel. This results in a substantial increase in the efficiency of the burner, which is consequently capable of developing very high heat outputs; for example, in a burner of the order of 5 million calories, the rate of discharge of liquid fuel in this burner increases from 500 kg/hr to 1,400 kg/hr in the case of a combustible fuel whereas, conversely, the external diameter of the unit can be reduced from 250 mm to only 123 mm.

In a first embodiment of the invention, the outer casing is connected to a single duct for the admission of the gas and the liguid which are intimately mixed before penetrating into the emulsion chamber through the longitudinal passageways of the main body.

In an alternative embodiment, the outer casing is connected to a duct provided for the admission of gas alone and encloses a separate internal coil for the liquid, the mixing of these constituents with the liquid fuel being carried out directly within the emulsion chamber.

Further charateristic features of a burner which is constructed in accordance with the present invention will become apparent from the following description of one example of construction which illustrates the practical application of the two embodiments contemplated above, reference being made to the single figure of the accompanying drawing which represents two longitudinal half-sectional views of said burner.

As can be seen from this figure, the burner which is shown essentially comprises a main body 1 and an axial duct 2 which is connected to the rear portion of said body. Provision is made at the end of said duct for an external screw-thread 3 on which is mounted a tubular end-piece 4 provided with a lateral orifice 5 for introducing into the duct 2 and conveying towards the body 1 one of the constituents of the ternary emulsion to be produced within the burner and especially the liquid fuel which, in the most general case, is a hydrocarbon such as a heavy fuel oil or a residual effluent of refining. The extremity of the endpiece 4 is closed by an internally threaded plug 6 traversed axially by an operating rod 7 which extends through the entire length of the duct 2. The portion of said rod 7 which is remote from the plug 6 comprises a head 8 terminating in a portion 9 forming a regulating needle, said head 8 being provided with longitudinal flutes 10 which serve to guide the needle 9 along the axis of the body 1 as a result of displacement of the rod 7. Moreover, the body 1 is provided with openings 11 in spaced relation around the head 8 and permitting the liquid fuel conveyed through the duct 2 to flow through the body 1 and finally to pass into the interior of a chamber 12 in which is effected the emulsion of the three constituents forming the mixture which is burned in the apparatus. The position of the needle 9 within the chamber 12 is adjusted by the axial position of the operating rod 7, said rod being subjected to the action of a spring 13 which is applied at one end against the head 8 and at the other end against an annular shoulder 1a provided within the body 1. At the end remote from the needle 9, the operating rod 7 has a threaded portion 7a cooperating with a nut 14 which serves to control the position of the rod, the passageway through the plug 6 which closes the end-piece 4 being formed in leak-tight manner through a gland 15 which is screwed into the plug 6 in such manner as to compress a leak-tight packing 16 and apply this latter in contact with the rod 7. There is formed in the external surface of the body 1 a threaded portion 17 on which is mounted a cover 18 forming the nozzle of the burner, said cover 18 being provided with a central opening 19 through which the needle 9 is engaged so that the relative displacement of this latter under the controlling action of the rod 7 regulates the flow rate of the emulsion which is discharged from the burner. Finally, there is mounted within the chamber 12 a distributor deflector consisting of an annular member 20 fixed on the body 1 and terminating in helical grooves 21 which serve to ensure homogeneous mixing of the different phases of the emulsion.

In accordance with the invention, the burner aforesaid comprises an outer casing 22 which is screwed at 22a onto the rear end of the body 1 and defines between the body, the internal surface of the casing and the external surface of the duct 2, a zone 23 closed by an end-plate 24 which closes said casing. The plate 24 is fitted with a packing-gland 25 through which the duct 2 is passed whilst its attachment to a flange 22b which is integral with said casing is carried out by means of locking-screws 26. Furthermore, provision is made on the lateral wall of the casing 22 for an inlet-connection 27 which serves to introduce into the zone 23 the other constituents of the ternary emulsion to be conveyed towards the chamber 12 of the burner.

In a first alternative embodiment, the two other constituents aforesaid, namely which consist respectively of air and water which is either pure or contains certain additives suited to the nature of the fuel, for example, are previously mixed together, then admitted through the inlet-connection 27 into the zone 23 from which they are discharged and passed through the body 1 towards the emulsion chamber 12 through longitudinal passageways 28 arranged in uniformly spaced relation around the duct 2 within the main body 1.

In another alternative embodiment, the inlet-connection 27 serves solely for the introduction of air into the zone 23, the water or more generally a suitable liquid which forms the third constituent of the emulsion being conveyed towards one or a number of the passageways 28 by means of coils such as the coil 29, the ends of which traverse the plate 24 through a packing-gland 30.

No matter what form of construction may be employed, the two additional phases of the emulsion which is consumed by the burner are brought to this latter in a region which is set back at a suitable distance from the body 1 and consequently from the emulsion chamber 12, which makes it possible to cool the burner body more effectively and to ensure a better energy yield of this latter. By permitting recovery of energy, this arrangement also makes it possible to reheat the two phases (air and water) along their flow path so that, after passing through the passageways 28, said phases are accordingly mixed with the liquid fuel (fuel oil) within the chamber 12 at a temperature which is close to that of said third constituent; this also constitutes a significant factor in the general improvement of the operating conditions of the burner. Finally, this arrangement permits the introduction of the burner in combustion chambers which are accessible only from a distance and more particularly in those of rotary furnaces for baking mineral products at high temperature (1,400° to 1,700° C), without causing any damage to this burner and consequently without entailing the need for frequent changes of fuel-injection tubes which have become clogged with deposits of coke or for any other reason.

It is readily apparent that this invention is not limited solely to the examples which have been described in the foregoing but extends to all alternative forms.