Title of Invention

AN IMPROVED BURNER OF EASILY ADJUSTABLE FLAME LENGTH FOR USE IN ROTARY KILNS

Abstract

An improved burner of easily adjustable flame length for use in rotary kilns, comprising an inner concentric tube (8) an outer concentric tube (9) and an outer nozzle (11) detachably fitted at the tip (16) of the outer tube, and an inner nozzle (11A) fitted detachably at the tip (16A) of the inner tube, characterised in that (a) the burner (7) is provided with a know emulsifier (1), as herein described, for primary atomisation of fuel oils supplied thereinto at a pressure of 3-7 kg/cm2 through a pipe (2) fitted with a non-return valve (2A), a control valve (2B), a pressure guage (2C), with steam or compressed air supplie thereinto at a pressure of 1.5-5.0 kg/cm2 through a pipe (3) fitted with a non-return valve (3A), a control valve (3B) and a pressure gauge (3C), and for supplying the emulsion of fuel oils and steam or compressed air produced therein into the annular space between the inner and outer tubes of the burner at the bacl end (10) thereof through a known metallic flexible hose (5); (b) the burner is provided with a known metallic flexible hose ( fitted with, a control valve (6A) and a pressure guage (6B) for supplying a separate stream of steam or compressed air at a pressure of 1.5-5.0 kg/cm2 into the inner tube of the burner at the back end (10) thereof; and (c) an atomiser (12) in the form of a solid cone is fitted with its wider end adjacent to the tip (15) of the outer nozzle and narrower end adjacent to the tip (1: of the inner nozzle for secondary atomisation of fuel oils in the said emulsion with the said separate stream of steam or compresse air flowing respectively through the annular space between the inner and outer tubes, and inner tube of the burner, and emerging at the tip of the outer nozzle through a set of inner holes (13) and a set of outer holes (14) provided adjacent to the periphery of the narrower end of the atomiser.

Full Text

The present invention relates to an improved burner of easily adjustable flame length for use in rotary kilns. The invention relates more particularly to a burner in which primary atomisation of fuel oil is performed outside the burner in an emulsifier in which both fuel oils and steam or compressed air are supplied at a relatively low pressure, and secondary atomisation of the oil-emulsion is carried out at the nozzle of the burner by supplying a separate stream of steam or compressed air at a relatively low pressure, and the length of the flame produced by the burner can be easily varried as required, by controlling the pressure of the said separate stream of steam or compressed air. A number of burners of different designs and construct operable from liquid fuels and/or gaseous fuels and suitable for applications in different fields have been disclosed by the applicants during the recent years in the following pending Indian Patent Applications :- (i) Patent Application NO. 406/Dal/95 filed on 10. 3o 95 (ii) n "19.1170 " 2233/Del/95 " " 4. 12. 95 (iii) n n " 2234/Del/95 " " 4. 12. 95 (iv) n n " 1037/Del/96 " " 17. 5. 96 (v) tt tt " 1515/Del/96 " " 10. 7. 96 (vi) tt n " 1714/Del/96 " " 31. 7. 96 (vii) tt n " 1840/Del/96 " " 19. 8. 96 (viii) n tt tt 1841/Del/96 " " 19. 8. 96 (ix) n n n 2/Del/97 " " 1. 1. 97 (x) tt tt tt 211/Del/97 " " 27. 1. 97 (xi) n tt tt 671/DB1/97 " " 17. 3. 97 (xii) n tt n 1882/Del/98 " " 3. 7. 98. - 2 - The existing burners meant for use in rotary kilns requires supplying fuel oils at a high pressure of around 10-20 kg/cm2 in one or two streams and allowing the pressur oils to exit through a relatively narrow hole of diameter 2-4 mm of the nozzle for atomisation of the oils before burnln thereof. In one design of the existing burners a solid cone i provided inside the nozzle, the position of which is varied by rotating a wheel fitted at the inlet end of the burner to control the flow rate of fuel oil through the nozzle hole and thereby the flame length of the burner to a limited extent only. In another design of the existing burners, a primary stream of fuel oil is allowed to exit directly through the nozzle hole and a secondary stream of fuel oil is allowed to exit through a number of narrow tangential slots cut on the nozzle surface, two streams being allowed to mix together and exit through a narrow hole of 2-4 mm diameter made at the cent: of a small orifice plate fitted at the top of the nozzle. The flame length is adjusted by replacing the orifice plate with another having a hole of bigger or smaller diameter requiring shutting down of the burner. The drawbacks of the existing burners meant for use in rotary kilns are :- (a) fuel oils are required to be supplied at a relative!? high /pressure of 10-20 Kg/cm2 by using a pump of relatively high initial and maintenance cost; - 3 - (b) the hole in the nozzle and orifice plate being narro i.e. 2-4 mm, it gets choked with dust and impurity in the oils frequently, requiring shutting down of the burner; (c) the cost of fabrication of the nozzle is high; and (d) the length of flame can not be adjusted easily to the desired extent. The object of the present invention is to provide a burner operating from fuel oils supplied at a relatively low pressure, in which the flame length can be easily adjusted to the required extent without the need for shutting down of the burner. The other object is to provide a burner requiring the supply of steam or compressed air for atomising the fuel oils at a relatively low pressure. Another object is to provide a burner in which the consumption of fuel oils is reduced, by about 4-596. A further object is to provide a. burner in which the nozzle holes are of relatively large diameter and hence are not choked by the dirts or dusts present in the fuel oils. The invented burner comprises an emulsifier, as disclosed in the Indian Patent Application No.1841/Del/96, provided outside the burner, for primary atomisation of fuel oils by preparing an emulsion of fuel oils and steam or compressed air, which is supplied from the back end of the burr through the annular space between an outer and an inner concentric tubes of the burner at a relatively low pressure for secondary atomisation of the oils in the emulsion inside the nozzle fitted detachably to the tip end of the burner. The -4- nozzle is provided with an atomiser comprising two sets of holes arranged around the periphery of the broad end of a solid cone, both sets being concentric with the burner axis with their axes inclined therewith outwardly towards the narrow exit end of the solid cone. The emulsion of oils and steam or compressed air is allowed to emit through the outer set, and the separate stream of steam or compressed air through the inner set of holes of the cone for causing secondary atomisation of oils therein. Thus the invention provides an improved burner of easily adjustable flame length for use in rotary kilns, comprising an inner concentric tube, an outer concentric tube, and an outer nozzle detachably fitted at the tip of the outer tube and an inner nozzle fitted detachably at the tip of the inner tube, characterised in that ,(a) the burner is provided unit, seek as herein described . with a known emulsifier/for primary atomisation of fuel oils supplied thereinto at a pressure of 3-7 kg/Cm2 through a pipe fitted with a non-return valve, a control valve, a pressure gauge, with steam or compressed air supplied thereinto at a pressure of 1.5-5.0 kg/cm through a pipe fitted with a non-retl valve, a control valve and a pressure gauge, and for supplying emulsion of fuel oils and steam or compressed air produced then into the annular space between the inner and outer tubes of the burner at the back end thereof through a known metallic flexible hose; (b) the burner is provided with a known metallic flexible hose fitted with a control valve and a pressure gauge for supplying a separate stream of steam or compressed air at a - 5 - pressure of 1.5-5.0 kg/cm2 into the inner tube of the burner at the back end thereof; and (c) an atomiser in the form of a solid cone is fitted with its wider end adjacent to the tip of the outer nozzle and narrower end adjacent to the tip of the inner nozzle for secondary atomisation of fuel oils in the said emulsion with the said separate stream of steam or compressed a: flowing respectively through the annular space between the inner and outer tubes, and inner tube of the burner, and emerging at the tip of the outer nozzle through a set of inner holes and a set of outer holes provided adjacent to the periphery of the narrower end of the atomieer. 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 diagram of the invented burner with the accessories thereof; Figure 2 is the enlarged sketch of the nozzle of the burner; Figure 2A is the view of the nozzle from direction A; Figure 2B is the view of the nozzle from direction B; and Figure 3 is the enlarged sketch of the emulsifier used for emulsifying fuel oils with steam or compressed air. Referring to Fig. 1, the invented burner is provided unit with an emulsifier/(1) located outside the burner, into which i.e. light Diesel oil, i.e. low sulphur heavy stock fuel oils such as LDO^ furnace oil, LSHS/and coal tar are fed 6 through pipe (2) fitted with non-return valve (2A), control valve (2B) and pressure gauge (2C); and steam or compressed air is supplied through pipe (3) also fitted with non-return valve (3A), control valve (3B) and pressure gauge (3C). Burner (7) comprises an inner concentric tube (8) and an outer concentric tube (9), an outer nozzle (11) and an inner nozzle (11A), an atomiser (12) in the form of a solid cone fitted with its wider end adjacent to the tip (15) of the outer nozzle and narrower end adjacent to the tip (15A) of the inner nozzle. A set of inner holes (13) and a set of outer holes (14) are provided adjacent to the periphery of the narrower end of the atomiser. The centres of the set of outer an holes lie on^outer circle concentric with the burner and nozzl axis. Similarly the centres of the set of inner holes lie on an inner circle concentric with the burner and nozzle axis. The inner and outer sets of holes are extended towards the wider end of the atomiser with their axes inclined outwardly from the burner and nozzle axis to meet at an angle of 20-60 with each other near the tip of the outer nozzle. The number of holes in each set is 4-16 and the diameter of holes in each set is 3-16 mm. The emulsion of fuel oils and steam or compressed ai unit produced in the emulsifier/is supplied into the annular space between the inner and outer tubes of the burner at its back end (10) through a flexible metallic hose (5) and allowed to emerge at the nozzle tip through the outer set of holes of the atomiser. - 7 - A separate stream of steam or compressed air is fed into the inner concentric tube of the burner at the back end thereof through a flexible metallic hose pine (6) fitted with control valve (6A) and pressure gauge (6B) and allowed to emerge through the inner set of atomiser holes for further atomising the fuel oil in the emulsion emerging through the outer set of holes at the tip of the nozzle. The emulsion flowing through the annular space between the outer and inner concentric tubes of the burner emerges to the outer nozzle tip through the set of outer holes, and the separate stream of steam or compressed air flowing through the inner concentric tube of burner emerges through the set of inner holes and causes secondarv atomisation of fuel oils in the emulsion. Referring to Fig. 2, 2A and 2B, the nozzle (11) is detachably fitted on the outer tube (9) of burner (7) near the tip end (16) thereof and comprises an atomiser (12) of the shape of solid cone having an outer set of holes (14) and an inner set of holes (13) at the periphery of the narrower end thereof, the axes of the two sets of holes (shown by dashed lint being inclined outwardly from the burner axis with an angle between the said axes, which meet each other near the tip (15) of the nozzle. In Fig. 2A the number of holes in the outer set is shown to be 14 and in Fig. 2B the number of holes in botl the inner and outer sets is shown to be 14. - 8 - Referring to Fig. 3, the emulsifier d), disclosed ir Indian Patent Application No.1841/Del/96, comprises an inner concentric tube (1A) and an outer concentric tube (1B). Fuel oil is fed into the inner tube through pipe (2) and steam or compressed air is fed into the annular space between the inner and outer tubes through pipe (3), and allowed to emerge into pipe (5) through the tapering outlet ends of said inner and outer tubes of the emulsifier in the form of an emulsion. Atomisation of fuel oils is performed in two stages unit (1) in the invented burner, firstly in the emulsifier/and secondly (12) as described herein before, at the atomiser/of nozzle^ Because of the two-stage atomisatic better atomisation of fuel oils is achieved at a reduced pressu of 3-7 kg/cm2 of oils and 1.5-5.0 kg/cm2 of steam or compressed air, against the corresponding pressure of 10-20 kg/cm2 require for the conventional burners. Better atomisation of fuel oils at a lower pressure of oils and steam or compressed air leads to a number of advantageous features of the invented burner over the conventic burners; these are : (a) the flame length is easily adjustable, as required, by varying the pressure of the separate stream of steam or compressed air supplied into the inner tube of the burner; (b) the flame of the burner is stable and firmly anchoi under cold as well as hot condition; (c) the 'turndown ratio' i.e. the ratio of maximum to minimum flow rate of fuel oils is high i.e. 10:1; (d) consumption fuel oils in the burner is reduced by about 4-5%; (e) the design of the nozzle is simple and so the cost of fabrication of the nozzle is low; (f) chokir of the nozzle holes is completely eliminated; (g) the flow rate - 9 - of fuel oils can be controlled without the need for changing the nozzle; (h) a low-pressure oil pump of reduced initial and maintenance cost can be used for operating the burner. - 10 - We Claim :- 1. An improved burner of easily adjustable flame length for use in rotary kilns, comprising an inner concentric tube (8) an outer concentric tube (9) and an outer nozzle (11) detachably fitted at the tip (16) of the outer tube, and an inner nozzle (11A) fitted detachably at the tip (16A) of the inner tube, charaterised in that (a) the burner (7) is provided with a know unit as herein described, emulsifier/(1), for primary atomisation of fuel oils supplied thereinto at a pressure of 3-7 kg/cm through a pipe (2) fitted with a non-return valve (2A), a control valve (2B), a pressure guage (2C), with steam or compressed air supplied thereinto at a pressure of 1.5-5.0 kg/cm2 through a pipe (3) fitted with a non-return valve (3A), a control valve (3B) and a pressure gauge (3C), and for supplying the emulsion of fuel oils and steam or compressed air produced therein into the annular space between the inner and outer tubes of the burner at the back end (10) thereof through a known metallic flexible hose (5); (b) the bur is provided with a known metallic flexible hose (6) fitted with control valve (6A) and a pressure gauge (6B) for supplying a separate stream of steam or compressed air at a pressure of 1.5-kg/cm into the inner tube of the burner at the back and (10) thereof; and (c) an atomiser (12) in the form of a solid cone is fitted with its wider end adjacent to the tip (15) of the outer nozzle and narrower end adjacent to the tip (15A) of the inner nozzle for secondary atomisation of fuel oils in the said emulsi with the said separate stream of steam or compressed air flowing - 11 - respectively through the annular space between the inner and outer tubes, and inner tube of the burner, and emerging at the tip of the outer nozzle through a set of inner holes (13) and a set of outer holes (14) provided adjacent to the periphery of the narrower end of the atomiser. 2, The improved burner as claimed in claim 1, wherein the inner and outer sets of holes are extended towards the wider end of the atomiser with their axes inclined outwardly from the burner and nozzle axis to meet at an angle with each other near the tip of the outer nozzle. 3. The improved burner as claimed in claim 2, wherein the angle between the axes of the inner and outer sets of holes in 20-60°. 4. The improved burner as claimed in any one of claims 1 to 3t wherein the inner and outer sets of holes are arranged with their centres lying on an inner circle and an outer circle respectively which are concentric with the burner and nozzle axis. 5. The improved burner as claimed in any one of claims 1 to 4, wherein the number of holes in both the inner and outer sets is 4 to 16, 6. The improved burner as claimed in any one of claims 1 to 5, wherein the diameter of each hole in the inner and outer sets is 3 to 16 mm. - 12 - 7. An improved burner of easily adjustable flame length for use in rotary kilns, substantially as herein described and illustrated in the accompanying drawings. - 13 - Dated this 24th day of December 1996. An improved burner of easily adjustable flame length for use in rotary kilns, comprising an inner concentric tube (8) an outer concentric tube (9) and an outer nozzle (11) detachably fitted at the tip (16) of the outer tube, and an inner nozzle (11A) fitted detachably at the tip (16A) of the inner tube, characterised in that (a) the burner (7) is provided with a know emulsifier (1), as herein described, for primary atomisation of fuel oils supplied thereinto at a pressure of 3-7 kg/cm2 through a pipe (2) fitted with a non-return valve (2A), a control valve (2B), a pressure guage (2C), with steam or compressed air supplie thereinto at a pressure of 1.5-5.0 kg/cm2 through a pipe (3) fitted with a non-return valve (3A), a control valve (3B) and a pressure gauge (3C), and for supplying the emulsion of fuel oils and steam or compressed air produced therein into the annular space between the inner and outer tubes of the burner at the bacl end (10) thereof through a known metallic flexible hose (5); (b) the burner is provided with a known metallic flexible hose ( fitted with, a control valve (6A) and a pressure guage (6B) for supplying a separate stream of steam or compressed air at a pressure of 1.5-5.0 kg/cm2 into the inner tube of the burner at the back end (10) thereof; and (c) an atomiser (12) in the form of a solid cone is fitted with its wider end adjacent to the tip (15) of the outer nozzle and narrower end adjacent to the tip (1: of the inner nozzle for secondary atomisation of fuel oils in the said emulsion with the said separate stream of steam or compresse air flowing respectively through the annular space between the inner and outer tubes, and inner tube of the burner, and emerging at the tip of the outer nozzle through a set of inner holes (13) and a set of outer holes (14) provided adjacent to the periphery of the narrower end of the atomiser.

Documents:

02214-cal-1998 abstract.pdf

02214-cal-1998 assignment.pdf

02214-cal-1998 claims.pdf

02214-cal-1998 correspondence.pdf

02214-cal-1998 description(complete).pdf

02214-cal-1998 drawings.pdf

02214-cal-1998 form-1.pdf

02214-cal-1998 form-2.pdf

02214-cal-1998 form-3.pdf

02214-cal-1998 gpa.pdf

2214-cal-1998-granted-abstract.pdf

2214-cal-1998-granted-assignment.pdf

2214-cal-1998-granted-claims.pdf

2214-cal-1998-granted-correspondence.pdf

2214-cal-1998-granted-description (complete).pdf

2214-cal-1998-granted-drawings.pdf

2214-cal-1998-granted-examination report.pdf

2214-cal-1998-granted-form 1.pdf

2214-cal-1998-granted-form 2.pdf

2214-cal-1998-granted-form 3.pdf

2214-cal-1998-granted-form 5.pdf

2214-cal-1998-granted-letter patent.pdf

2214-cal-1998-granted-pa.pdf

2214-cal-1998-granted-reply to examination report.pdf

2214-cal-1998-granted-specification.pdf