The present invention relates to an improved injection type burner operating from a liquid fuel and compressed air or oxygen.
The invention relates more particularly to a burner which is capable of burning liquid fuels of different types, such as herein described, at a rate ranging from 100 to 2000 litre per hour for producing a high thrust flame for ladles, reheating furnaces and boilers without using any blower for supplying air and in which an emulsion is formed in a mixing tube of a liquid fuel injected in the form of a high pressure jet through a nozzle and atomized by compressed air or oxygen supplied under high pressure simultaneously through another nozzle surrounding the former nozzle in the diverging part thereof the emulsion being discharged at a supersonic velocity of 350-400 m/sec at the junction of the converging and diverging parts of an air duct surrounding the mixing tube to create a suction there, which draws in atmospheric combustion air at the inlet of the converging part of the air duct through a damper, the outlet of the diverging part of the air duct being connected to the input of a refractory block for producing a stable flame at the output of the block.
In Indian Patent No. 191170 a duel fuel burner operating from lean gases and high-viscous oils supplied simultaneously or singly is disclosed.
In the pending Indian Patent No. 2234/Del/95 a dual fuel burner operating from lean gases and low-viscous oil supplied simultaneously or singly is disclosed.
In Indian Patent No. 192818 a tube-in-tube type high velocity gas burner operable from an emulsion of gas and compressed air is disclosed.
In the accepted Indian Patent Application No. 1841 /Del/96 a burner operable from an emulsion of liquid fuel and compressed air/steam or an emulsion of gas and air is disclosed.
In the pending Indian Patent Application No.211/Del/97, a dual fuel burner capable of producing a short turbulent flame from gases and liquid fuels supplied singly is disclosed.
In the pending Indian Patent Application No.671/Del/97 a burner of improved design and construction operating from an emulsion of gaseous fuels and air is disclosed.
An injection type burner operating from high pressure fuel gases injected into the burner in the form a high velocity jet producing a suction to draw in atmospheric combustion air either directly or through a recuperator is known in the prior art.
But there is a need for an injection type burner operating from liquid fuels such as furnace oil, tar, Pitch Creosite Mixture (PCM), Low Sulphur High Stock (LSHS) fuel oil, Light Diesel Oil (LDO), Kerosene and High Speed Diesel (HSD) oil, which are available, at a relatively low cost and large quantity, for producing a high thrust flame of high temperature suitable for heating ladles and reheating furnaces and boilers, without using a capital intensive blower for supplying combustion air into the burner.
The object of the present invention is to provide an injection type burner operating from liquid fuels and capable of firing liquid fuels at a rate ranging from 100 to 2000 litre per hour.
Thus the invention provides an improved injection type burner operating from a liquid fuel and compressed air or oxygen, which is capable of burning liquid fuels of different types, such as herein described, at a rate ranging from 100 to 2000 litre per hour for producing a high thrust flame for heating ladles, reheating furnaces and boilers without using any blower for supplying air, characterized in that the burner comprises an atomizing nozzle having a sraight part, a converging part, a diverging part, and a critical section for supplying compressed air at a pressure of 3-5 kg/cm2 or oxygen at a pressure of 5-10 kg/cm2 through an inlet and allowing the same to expand at a velocity of 300-340 m/sec at the critical section and at a velocity of 350-400 m/sec at diverging part thereof; an oil nozzle which is disposed co-axially inside the atomizing nozzle and provided with an inlet for entry of liquid fuel under pressure and an outlet located in the diverging part of the atomizing nozzle for exit of the liquid fuel thereinto in the form of a high pressure jet; a mixing tube connected by welding to the outlet of the diverging part at a position for producing therein an emulsion of atomized liquid fuel with compressed air or oxygen supplied thereinto through the atomizing nozzle; an air duct having a straight part for allowing the entry of atmospheric combustion air through damper at the required rate thereinto, and a converging part and a diverging part at the junction of which the emulsion of atomized liquid fuel and compressed air or oxygen produced in the mixing tube is allowed to be discharged at a velocity of 350-400 m/sec, creating thereby a suction thereat to draw in the atmospheric combustion air through damper and reduce the velocity of the emulsion to 3-5 m/sec in the diverging part for a thorough mixing of the emulsion with the combustion air therein,- and a refractory block having an
inlet connected to the outlet of the diverging part of the air duct and an outlet for exit of a flame stabilised by the block.
The invention is described fully and particularly without restricting the scope of the invention in any manner with reference to the accompanying drawings in which
Figure 1 is a schematic sketch of the longitudinal section of the invented burner.
Referring to Fig. 1, the burner comprises an atomising nozzle (1) which is provided with an inlet (3), a straight part
(1a), a converging part (1b) and a diverging part (5) for
2 supplying compressed air at a pressure of 3-5 kg/cm or
2 compressed oxygen at a pressure of 5-10 kg/cm and allowing the
same to expand at a sonic velocity at critical section (4) lying
at the junction of the converging part (1b) and diverging part
(5) and at a supersonic velocity in the diverging part (5) of
the atomising nozzle; an oil nozzle (2) having an inlet (2a)
for entry of liquid fuel under pressure and an outlet (2b)
located in the diverging part (5) of the atomising nozzle for the
exit of a high pressure jet, of liquid fuel into the diverging
part (5) of the atomising nozzle; a mixing tube (6) connected by
welding to the outlet of the diverging part (5) at a position (7)
for producing therein an emulsion of atomised liquid fuel with
the compressed air or oxygen supplied thereinto through the
atomising nozzle; an air duct (8) having a straight Part (9) with
a damper (10) for allowing entry of atmospheric combustion air
into the duct at a controlled rate, and a converging part (11)
and a diverging part (12) at the junction (13) of which the
emulsion of atomised liquid fuel and compressed air or oxygen produced in the mixing tube (6) is allowed to be discharged at a supersonic velocity, creating a suction thereat to draw in the atmospheric air for combustion through damper (10) which may be a butterfly type valve; and a refractory block (14) having an inlet (15) connected to the outlet of the diverging part (12) and an outlet (16) for exit of a flame which is stabilised by the block. The velocity at which the emulsion of atomised liquid fuel and compressed air or oxygen is discharged at the junction (13) is typically 300-400 m/sec and that in the divergent part (12) reduces to a low value of 3-5 m/sec, facilitating thereby a thorough mixing of the emulsion with the atmospheric combustion air.
The typical dimensions of different parts of the burner are presented in Table I.
Table I.
Typical Dimensions of Different Parts of the Burner.
(Table Removed)
The invented burner has been found to be capable of burning liquid fuels of different types such as hereinbefore stated at a rate of 100 to 2000 litre per hour and of producing a high thrust flame suitable for heating ladles, and reheating furnaces and boilers at a reduced cost because of the elimination of the blower required for supplying atmospheric air for the combustion of the fuel oil in the non-injection type burners.

We Claim :-
1. An improved injection type burner operating from a liquid fuel and compressed air or oxygen, which is capable of burning liquid fuels of different types, such as herein described, at a rate ranging from 100 to 2000 litre per hour for producing a high thrust flame for heating ladles, reheating furnaces and boilers without using any blower for supplying air, characterized in that the burner comprises an atomizing nozzle (1) having a sraight part (la), a converging part (lb), a diverging part (5), and a critical section (4) for supplying compressed air at a pressure of 3-5 kg/cm2 or oxygen at a pressure of 5-10 kg/cm2 through an inlet (3) and allowing the same to expand at a velocity of 300-340 m/sec at the critical section (4) and at a velocity of 350-400 m/sec at diverging part (5) thereof; an oil nozzle (2) which is disposed co-axially inside the atomizing nozzle and provided with an inlet (2a) for entry of liquid fuel under pressure and an outlet (2b) located in the diverging part (5) of the atomizing nozzle for exit of the liquid fuel thereinto in the form of a high pressure jet; a mixing tube (6) connected by welding to the outlet of the diverging part at a position (7) for producing therein an emulsion of atomized liquid fuel with compressed air or oxygen supplied thereinto through the atomizing nozzle; an air duct (8) having a straight part (9) for allowing the entry of atmospheric combustion air through damper (10) at the required rate thereinto, and a converging part (11) and a diverging part (12) at the junction (13) of which the emulsion of atomized liquid fuel and compressed air or oxygen produced in the mixing tube is allowed to be discharged at a velocity of 350-400 m/sec, creating thereby a suction thereat to draw in the atmospheric combustion air through damper (10)
and reduce the velocity of the emulsion to 3-5 m/sec in the diverging part (12) for a thorough mixing of the emulsion with the combustion air therein; and a refractory block (14) having an inlet (15) connected to the outlet of the diverging part of the air duct and an outlet (16) for exit of a flame stabilized by the block.
2. The burner as claimed in claim 1, wherein the damper is a butterfly type of valve.
3. The burner as claimed in claim 1, wherein the critical section is located at the junction of the converging and diverging parts of the atomizing nozzle.
4. An injection type burner operating from the liquid fuel and compressed air or oxygen substantially as herein described and illustrated in the accompanying drawings.