US3630649A - Shrouded gas burners and jets therefor - Google Patents

Shrouded gas burners and jets therefor Download PDF

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US3630649A
US3630649A US846832A US3630649DA US3630649A US 3630649 A US3630649 A US 3630649A US 846832 A US846832 A US 846832A US 3630649D A US3630649D A US 3630649DA US 3630649 A US3630649 A US 3630649A
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orifices
gas
shroud
flames
jet
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John Hancock
Albert Westerman
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Geo Bray and Co Ltd
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    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23DBURNERS
    • F23D14/00Burners for combustion of a gas, e.g. of a gas stored under pressure as a liquid
    • F23D14/46Details, e.g. noise reduction means
    • F23D14/48Nozzles

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  • ABSTRACT A shrouded gas burner which can be used for all gases and in particular natural gas at operating pressures of 6-10 inches water gauge. in all the burners described an array of closely spaced diverging flames is produced which coalesce over a part of their length only thereby achieving both mutual stabilization and satisfactory aeration of the flames as a whole.
  • the use of a shroud around the coalesced region of the flames protects them from direct airflow and contains the products of combustion near to the reaction zone so that they may be reentrained thereby accelerating the combustion process.
  • PATENTED DEC28197I 31530549 sum 2 [IF 5 PATENTED UEB28 l97l 3330.549
  • This invention relates to shrouded gas burners for use with gases having different compositions and qualities, and in particular to the construction of a gas burner which provides stable nonaerated flames with natural gas at operating pressures of approximately 6-10 inches water gauge.
  • a shrouded burner includes in combination a gas-jet having a plurality of gas orifices producing, in use, diverging flames which coalesce only in the region of the gas orifices, and a shroud having at least one wall, said at least one wall protecting the gas orifices from direct airflow and being shaped dimensioned so that a given flame passes in close proximity to the peripheral edge thereof, said peripheral edge being contoured so that the maximum design gas pressure the point of divergence of adjacent flames is level with said edge and at minimum design gas pressure the point of divergence of adjacent flames is slightly below said edge.
  • FIG. 1 shows a diagrammatic plan view of a first jet
  • FIG. 2 shows a section taken on the line A-A of FIG. 1;
  • FIG. 3 shows a section on the line 8-8 of FIG. 1;
  • FIGS. 4 and 5 show diagrammatic part sectional side and end views respectively of a shrouded burner incorporating the jet shown in FIGS. 1 to 3, and illustrate the flame shape and airflow pattern obtained;
  • FIG. 6 shows a diagrammatic plan view of asecond jet
  • FIG. 7 shows a section taken on the line CC of FIG. 6
  • FIG. 8 shows a diagrammatic part sectional view respectively of a shrouded burner incorporating the jet shown in FIGS. 6 and 7, and illustrate the flame shape and airflow pattern obtained;
  • FIG. 9 shows a diagrammatic plan view of a third jet
  • FIG. 10 shows a section on the line D-D of FIG. 9;
  • FIGS 11 and 12 show diagrammatic part sectional side and end views respectively of a shrouded burner incorporating the jet shown in FIGS. 9 and I0, and illustrate the flame shape and airflow pattern obtained;
  • FIG. 13 shows a diagrammatic plan view of the burner illustrated in FIGS. 11 and 12;
  • FIG. I4 shows a diagrammatic plan view of a fourth jet
  • FIG. 15 shows a section on the line E-E of FIG. 14;
  • FIGS. 16 and 17 show diagrammatic part sectional side and end views respectively of a shrouded burner incorporating the jet shown in FIGS. 14 and I5 and illustrate the flame shape and airflow pattern obtained;
  • FIGS. 18 shows a diagrammatic plan view of the burner illustrated in FIGS. I6 and 17;
  • FIGS. 19 and 20 are axial sectional and plan views respectively illustrating yet another embodiment of the invention.
  • a ceramic or metal gas jet indicated generally at 1 has a spherical projection 2'in which are formed eight orifices 3, 4.
  • the orifices 3, 4 are circular and are. normal to the external surface of the jet, that is their origin is the center of the sphere in which they are formed.
  • the set of orifices 3 are formed in one of two planes (one of which, A- A is shown in FIG. 1) each of which is at an angle of l0-20 from the plane X-X, which is the major axis of the final flame which is in the form of a closed elliptical ring, and the set of orifices 4 are formed in one of two planes (one of which B-B is shown in FIG.
  • FIG. 2 which is a section through A-A, the orifices 3 are inclined at 3040 to the longitudinal axis of the jet and in FIG. 3, a section through 8-8, the orifices4 are at I520 to the longitudinal axis of the jet.
  • the two sets of orifices 3, 4 have the same common point of intersection on the longitudinal axis of the jet it is quite possible for each set of orifices to have a different point of intersection on this axis.
  • FIGS. 4 and 5 A complete shrouded burner incorporating the jet illustrated in FIGS. 1 to 3, is shown in FIGS. 4 and 5.
  • the jet is mounted into a metal socket 5 which is provided with an annular shoulder 6 for receiving a shroud 7.
  • the vertical distance of the orifices below the highest point of .the shroud are of the order of 0.4 inch for orifices of 0.010 inch to 0.015 inch diameter and for the angles of divergence stated above.
  • the dimensions of the cavity 10, which is of generally wedge-shaped section, formed between the flames and the wall of the shroud is also of importance since it is in this area that recirculation of the products of incomplete combustion occurs and the volume of the latter have to be related to the volume of the cavity for purposes of stabilization.
  • the internal diameter of the shroud around the jet is 0.30 inch, the internal width at the top in the minor axis is 0.45 inch, and the internal length at the top in the major axis is 0.84 inch.
  • the jet can be used with natural gas without flame lift at pressures of up to 12 inches water gauge and has well aerated flames.
  • FIGS. 6 to 8 A preferred form of jet giving a final flame which is substantially circular in plan view, is illustrated in FIGS. 6 to 8.
  • Four 0.0l3-inch diameter circular orifices 11 are formed in the hemispherical portion 12, of a jet 13.
  • the portion 12 has an external radius of 0.105 inch and the angles between the longitudinal axis of adjacent orifices is 24
  • the angle between the longitudinal axis of each orifice and the longitudinal axis of the jet is 17.
  • FIG. 8 illustrates thejet 13 mounted on a metal socket 14 provided with an annular projection 15 for receiving a shroud I6.
  • the latter takes the form of an inverted truncated cone with an internal diameter around the jet of 0.30 inch, an internal diameter at the top of 0.55 inch, the top of the shroud being 0.40 inch above the apex of the jet.
  • Jets with up to 12 orifices can be designed to produce circular plan flames. In general terms, it is desirable that the angle between the longitudinal axes of adjacent orifices falls between 20 and 30. In order to satisfy this condition, the angle between the longitudinal axis of each orifice and the longitudinal axis of the jet has to be in the range of 10 to 45 dependent upon the number of orifices used and their angle of divergence.
  • FIG. 8 shows the final flow pattern, indicated by arrows, and flame formation achieved by the shrouded burner. It will be seen that the burner again produces a coalesced flame portion and that reverse airflow is obtained between the flames themselves and between the flames and the peripheral edge of the wall of the shroud.
  • FIGS. 9 and 10 A jet 18 which produces a thin flame is shown in FIGS. 9 and 10, and has five orifices 19, the three inner ones being of 0.0125 inch diameter, and the two outer ones being of 0.0095 inch diameter,
  • FIGS 11 to 13 illustrate the jet 18 mounted for a metal socket 21 provided with an annular projection 22 for receiving a shroud 23. Because in this case there is no lateral divergence of the flames, the side portions of the wall of the shroud 22 are parallel, as shown, or they may be slightly convergent, in order to regulate the flow of air into the shroud through the cleance between the lip and the flame and in order to contain the combustion products near to the flame base.
  • the maximum width of the mouth of the shroud is 0.312 inch, the length is 1.007 inches and the tip of the jet is 0.570 inches below the uppermost point of the shroud.
  • the five orifices 19 are of slightly larger diameter, the three inner ones being 0.145 inches and the two outer ones 0.01 inches.
  • the external radius of the projection is 0.135 inches.
  • the external radius of the projection 20 must be adjusted in accordance with orifice diameter in order to maintain a fairly constant ratio between orifice diameter and orifice center spacing.
  • the dimensions of the shroud, for this example are, width of mouth 0.312, length of mouth 1.100 inches and the tip of the jet is 0.570 inches below the uppermost point of the shroud.
  • the five orifices could all be of equal size or they could all be different since the relative diameters only affect the overall flame shape.
  • FIGS. 11 and 12 illustrate the flame formation and the airflow pattern achieved. It will be seen that reverse airflow still occurs between the outer surface of the flames and the lip of the shroud and the products of incomplete combustion are retained for recirculation in the wedge-shaped gap 25 formed between the flame and the wall of the shroud.
  • FIGS. 14 and 15 The jet 26 is provided with a linear or row of 11 orifices 27 of 0.0117 inches diameter formed in a spherically contoured projection 28 of external radius 0.093 inches with an angle of 18 between the axes of adjacent orifices.
  • a complete shrouded burner incorporating the jet 26 is shown in FIGS. 16 to 18.
  • the jet is mounted on a metal socket 29 provided with an annular shoulder 30 for receiving a shroud indicated generally at 31.
  • the shroud consists of two substantially semicircular parallel walls 32 of 0.687 inches radius and have a separation of between 0.260 inches and 0.312 inches depending on the orifice diameters which are approximately 0.0117 inches.
  • the walls may be parallel as shown or slightly convergent and are closed at the bottom by a pair of flat plates 33 which project from the jet at an angle of about 10 below the horizontal FIGS. 16 an 1? illustrate the final flame formation and the airflow pattern depicted by the arrows.
  • the principle of reverse airflow counter to the flow of gas and over the lips of the walls of the shroud again applies with the products of combustion being retained for recirculation in the wedge-shaped gaps 35 formed between the flame and the walls of the shroud.
  • a modified jet now shown, of the same general form as the jet 26 can be used with a double row of orifices with an angle of 24 between the longitudinal axes of the orifices in each row with the shroud suitably modified, and with the angles of divergence between the longitudinal axes of the adjacent orifices increased to 25 to allow airflow between the two rows of flame.
  • a further development which is not illustrated, is to have 20 0.012 inches diameter orifices around the circumference of a jet of 0.18 inches diameter with an angle of 18 between the axes of adjacent orifices and with these axes at to the axis of the jet, so that all flames project horizontally from the jet.
  • a circular disc 1.25 inches diameter is positioned below the onfices and another above the orifices with the surfaces of both flaring away from the jet at angles of 15 below and above the horizontal respectively.
  • the orifice dimensions of the various embodiments described above can be modified where necessary. As the orifices are reduced in size, the rate of flow of gas will decrease as will the volume of combustion products produced on ignition, and hence for the purpose of mutual stabilization the orifice spacing has to be reduced. Conversely, with larger orifices, the orifice spacing has to be increased. Furthemtore, it will be understood that the orifices for each jet described may all be the same size or they may be all different, change in orifice dimensions only affecting flame length and hence overall flame shape. Moreover, the number of orifices and their disposition one to another can be varied in order to obtain different overall flame shapes.
  • the induced air flow and the volume of the combustion products vary according to on'fice diameter and the flow of gas therefrom and consequently the dimensions of the jets and shrouds must be varied correspondingly.
  • the longitudinal axes of all the orifices or sets of orifices of each embodiment described above diverge from a common origin. However, diverging flames can also be obtained by having orifices with parallel axes formed in a thin section or diaphragm as illustrated in FIGS. 19 and 20.
  • the jet has a cylindrical wall 40 surmounted by a frustum of a cone 41, the orifices 42 being formed in the conical surface and being arranged parallel to the axis of the jet.
  • the angle at which the flames leave the jet can be altered by altering the thickness of the conical or diaphragm portion. This method of manufacture of jets would be particularly applicable to the jet illustrated in FIGS. 6 and 7.
  • the top or lip of the shroud is contoured so that at maximum design gas pressure the point of divergence of adjacent flames is level with the lip, and that at minimum design gas pressure the pint of divergence is slightly below the level of the lip.
  • the burners provide stable nonaerated flames with natural gas at operating pressures of approximately 6-10 inches water gauge.
  • the dimensions specified are those which produce stable flames with methane at operating pressures of between 6 and 10 inches water gauge.
  • jets and burners have been described but it will be evident that other designs based upon the principles listed in the foregoing paragraph are possible. There is also no reason why these principles should not be applied in the design of so-called ribbon burners, for example, in which orifices may be formed in projections on the upper face of a continuous channel member, and a shroud of section appropriate to the required flame shape is placed around each projection.
  • the jets described can also be used in the design of aerated burners in which case the orifices would have to be rather larger to allow for the increased flow arising from premixing of air with the gas before it issues from the orifices.
  • a shrouded burner including in combination a gas jet having a plurality of gas orifices lying on a common ellipse producing, in use, diverging flames which coalesce only in the region of the gas orifices, and a shroud having at least one wall, said at least one wall protecting the gas'orifices from direct airflow and being shaped and dimensioned so that a given flame passes in close proximity to the peripheral edge thereof, said peripheral edge being contoured so that at the maximum design gas pressure the point of divergence of adjacent flames is level with said edge and at minimum design gas pressure the point of divergence of adjacent flames is slightly below said edge.
  • a burner as claimed in claim 11 in which the walls of the shroud are generally elliptical.
  • a burner as claimed in claim 2 in which two sets of orifices are provided the longitudinal axes of the orifices in each set having a ditferent common point of intersection on the longitudinal axis of the jet.
  • a shrouded burner for providing stable nonaerated flames with natural gas at operating pressures of approximately 6 to 10 inches water gauge including in combination a gas jet having a plurality of gas orifices producing, in use, diverging flames which coalesce only in the region of the gas orifices, and a shroud for protecting the gas orifices from direct airflow in which:
  • the shroud having an internal diameter around the jet of the order of 0.30 inches (5 percent), an internal wid h at the top in the minor axis of the order to 0.45 inch (5 percent), and an internal length at the top in the major axis of the order of 0.84 inch (5 percent), the distance of the orifices below the highest point of the shroud being of the order of 0.40 inch (5 percent), whereby a given flame passes in close proximity to the peripheral edge of the shroud, and whereby at the maximum design
  • a shrouded burner for providing stable nonaerated flames with natural gas at operating pressures of approximately 6 to 10 inches water gauge including in combination a gas jet having a plurality of gas orifices producing, in use, diverging flames which coalesce only in the region of the gas orifices, and a shroud protecting the gas orifices from direct airflow in which:
  • the orifices lie on a common circle and have diameters of the order of 0.013 inch (5 percent), the angle between the longitudinal axis of adjacent orifices being of the order of 20 to 30 and that between the longitudinal axis of each orifice and the longitudinal axis of the jet being of the order of 10 to 45, and in which the shroud is in the form of an inverted truncated cone the shroud having'an internal diameter around the jet of the order of 0.30 inch (5 percent) and an internal diameter at the top of the order of 0.55 inch (5 percent), the distance of the orifices below the highest point of the shroud being of the order of 0.40 inch (5 percent), whereby a given flame passes in close proximity to the peripheral edge of the shroud and whereby at the maximum design gas pressure the point of divergence of adjacent flames is level with said edge and at minimum design gas pressure the point of divergence of adjacent flames is slightly below said edge.
  • a shrouded burner for providing stable nonaerated flames with natural gas at operating pressures of approximately 6 to 10 inches water gauge including in combination a gas jet having a plurality of gas orifices producing, in use, diverging flames which coalesce only in the region of the gas orifices, and a tubular shroud for protecting the gas orifices from direct airflow in which:
  • the orifices line in common plane containing the longitudinal axis of the jet and have diameters of 0.0095 inch to 0.0145 inch (5 percent), the angle between the longitudinal axis of adjacent orifices being of the order of 17, and in which a pair of opposed walls of the shroud are substantially planar in configuration, the walls being parallel or slightly upwardly convergent with respect to the longitudinal plane containing the orifices, the maximum width of the mouth of the shroud being of the order of 0.312 inch (5 percent), the length of the mouth being of the order of 1.077 inch to 1.100 inch (5 percent), and the tip of the jet being of the order of 0.570 inch (5 percent) below the uppermost point of the shroud, whereby a given flame passes in close proximity to the peripheral edge of the shroud and whereby at the maximum design gas pressure the point of divergence of adjacent flames is level with said edge and at minimum design gas pressure the point of divergence of adjacent flames is slightly below said edge.
  • a shrouded burner as claimed in claim 6 in which: there are five orifices, the three inner orifices having a diameter of the order of 0.0125 inch (5 percent) and the two outer orifices having a diameter of the order of 0.0095 inch (5 percent).
  • a shrouded burner for providing stable nonaerated flames with natural gas at operating pressures of approximately 6 to 10 inches water gauge including in combination a gas jet having a plurality of gas orifices producing, in use, diverging flames which coalesce only in the region of the gas orifices, and a shroud for protecting the gas orifices from direct airflow, in which:
  • the orifices lie in a common plane containing the longitudinal axis of the jet and have diameters of the order of 0.0117 inch (5 percent), the angle between the longitudinal axis of adjacent orifices being of the order of 18 and in which the shroud consists of two substantially semicircular substantially parallel walls of the order of 0.687 inch (5 percent) radius and having a separation of the order of between 0.260 and 0.312 inch (5 percent), whereby a given flame passes in close proximity to the peripheral edges of said walls and whereby at the maximum design gas pressure the point of divergence of adjacent flames is level with said edges and at minimum design gas pressure the point of divergence of adjacent flames is slightly below said edge.
  • a shrouded burner as claimed in claim 9 in which:
  • the walls are closed at the bottom by a pair of flat plates which project from the jet at an angle of about 10 below the horizontal.
  • a shrouded burner including in combination a gas jet having a cylindrical wall surmounted by a frustum of a cone, a plurality of gas orifices being formed in the conical surface and being arranged parallel to the longitudinal axis of the jet so as to produce, in use, diverging flames which coalesce only in the region of the gas orifices, and a shroud having at least one wall, said at least one wall protecting the gas orifices from direct airflow and being shaped and dimensioned so that a given flame passes in close proximity to the peripheral edge thereof, said peripheral edge being contoured so that at the maximum design gas pressure the point of divergence of adjacent flames is level with said edge and at minimum design gas pressure the point of divergence of adjacent flames is slightly below said edge.
  • a shrouded burner including in combination a gas jet having a plurality of gas orifices lying in a common plane containing the longitudinal axis of the jet and producing, in use, diverging flames which coalesce only in the region of the gas orifices, and a shroud having at least one wall, said at least one wall protecting the gas orifices from direct airflow and being shaped and dimensioned so that a given flame passes in close proximity to the peripheral edge thereof, said peripheral edge being contoured so that at the maximum design gas pressure the point of divergence of adjacent flames is level with said edge and at minimum design gas pressure the point of divergence of adjacent flames is slightly below said edge.
  • a burner as claimed in claim 14 in which the walls are closed at the bottom by a pair of flat plates.

Abstract

A shrouded gas burner which can be used for all gases and in particular natural gas at operating pressures of 6-10 inches water gauge. In all the burners described an array of closely spaced diverging flames is produced which coalesce over a part of their length only thereby achieving both mutual stabilization and satisfactory aeration of the flames as a whole. The use of a shroud around the coalesced region of the flames protects them from direct airflow and contains the products of combustion near to the reaction zone so that they may be reentrained thereby accelerating the combustion process.

Description

United States Patent Inventors John Hancock Leeds; Albert Westerman, Normanton, both of England Appl. No. 846,832
Filed Aug. 1, 1969 Patented Dec. 28, 1971 Assignee Geo. Bray 8: Company Limited Leeds, England Priority Aug. 20, 1968 Great Britain 39,712/68 SIIROUDED GAS BURNERS AND JETS THEREFOR 15 Claims, 20 Drawing Figs.
US. Cl 431/353, 431/350, 239/499 Int. Cl. F2311 15/02 Field of Search 431/350, 353; 239/499 Primary Examiner-Carroll B. Dority, Jr. Attorney-Holcombe, Wetherill & Brisebois ABSTRACT: A shrouded gas burner which can be used for all gases and in particular natural gas at operating pressures of 6-10 inches water gauge. in all the burners described an array of closely spaced diverging flames is produced which coalesce over a part of their length only thereby achieving both mutual stabilization and satisfactory aeration of the flames as a whole. The use of a shroud around the coalesced region of the flames protects them from direct airflow and contains the products of combustion near to the reaction zone so that they may be reentrained thereby accelerating the combustion process.
PATENTED DEC28197I 31530549 sum 2 [IF 5 PATENTED UEB28 l97l 3330.549
SHEET u 0F 5 SI'IROUDED GAS BURNERS AND JETS THEREFOR This invention relates to shrouded gas burners for use with gases having different compositions and qualities, and in particular to the construction of a gas burner which provides stable nonaerated flames with natural gas at operating pressures of approximately 6-10 inches water gauge.
According to the present invention a shrouded burner includes in combination a gas-jet having a plurality of gas orifices producing, in use, diverging flames which coalesce only in the region of the gas orifices, and a shroud having at least one wall, said at least one wall protecting the gas orifices from direct airflow and being shaped dimensioned so that a given flame passes in close proximity to the peripheral edge thereof, said peripheral edge being contoured so that the maximum design gas pressure the point of divergence of adjacent flames is level with said edge and at minimum design gas pressure the point of divergence of adjacent flames is slightly below said edge.
By arranging for coalescence of the flames in the region of the gas orifices mutual stabilization of the flames is ensured. The shroud and its particular shaping effectively protects the coalesced region from the upward movement of air produced by convection currents and thereby further enhances flame stability. Consequently, flame lift is prevented even when natural gas is utilized at operating pressures of up to 10 inches water gauge.
Further, by producing diverging flames which coalesce over a part of their length only both mutual stabilization and satisfactory aeration of the flames is achieved. The divergence of the flames and also the fact that each of them is arranged to pass in close proximity to the lip of the shroud also helps flame stabilityby the formation of a current of air which passes between the gap formed between the flames and the lip of the shroud. This current of air is in a direction counter to the upward velocity of the gas flow and consequently the latter is effectively reduced, whilst the products of combustion will be retained in the gap formed between the flames and the walls of the shroud where they recirculate. Furthermore, in the case of a cluster of flames or a final closed ring of flame the divergence of the flames will help to contain the products of incomplete combustion within the cluster or ring.
The invention will now be described in more detail, by way of example, with reference to the accompanying drawings of which;
FIG. 1 shows a diagrammatic plan view of a first jet;
FIG. 2 shows a section taken on the line A-A of FIG. 1;
FIG. 3 shows a section on the line 8-8 of FIG. 1;
FIGS. 4 and 5 show diagrammatic part sectional side and end views respectively of a shrouded burner incorporating the jet shown in FIGS. 1 to 3, and illustrate the flame shape and airflow pattern obtained;
FIG. 6 shows a diagrammatic plan view of asecond jet;
FIG. 7 shows a section taken on the line CC of FIG. 6;
FIG. 8 shows a diagrammatic part sectional view respectively of a shrouded burner incorporating the jet shown in FIGS. 6 and 7, and illustrate the flame shape and airflow pattern obtained;
FIG. 9 shows a diagrammatic plan view of a third jet;
FIG. 10 shows a section on the line D-D of FIG. 9;
FIGS 11 and 12 show diagrammatic part sectional side and end views respectively of a shrouded burner incorporating the jet shown in FIGS. 9 and I0, and illustrate the flame shape and airflow pattern obtained;
FIG. 13 shows a diagrammatic plan view of the burner illustrated in FIGS. 11 and 12;
FIG. I4 shows a diagrammatic plan view of a fourth jet;
FIG. 15 shows a section on the line E-E of FIG. 14;
FIGS. 16 and 17 show diagrammatic part sectional side and end views respectively of a shrouded burner incorporating the jet shown in FIGS. 14 and I5 and illustrate the flame shape and airflow pattern obtained;
FIGS. 18 shows a diagrammatic plan view of the burner illustrated in FIGS. I6 and 17; and
FIGS. 19 and 20 are axial sectional and plan views respectively illustrating yet another embodiment of the invention.
Referring to FIGS. 1 to 3, a ceramic or metal gas jet indicated generally at 1 has a spherical projection 2'in which are formed eight orifices 3, 4. The orifices 3, 4 are circular and are. normal to the external surface of the jet, that is their origin is the center of the sphere in which they are formed. The set of orifices 3 are formed in one of two planes (one of which, A- A is shown in FIG. 1) each of which is at an angle of l0-20 from the plane X-X, which is the major axis of the final flame which is in the form of a closed elliptical ring, and the set of orifices 4 are formed in one of two planes (one of which B-B is shown in FIG. 1) each of which is at an angle of 40-60 from the plane X--X. In FIG. 2, which is a section through A-A, the orifices 3 are inclined at 3040 to the longitudinal axis of the jet and in FIG. 3, a section through 8-8, the orifices4 are at I520 to the longitudinal axis of the jet. Although in the gas jet illustrated in FIGS. 1 to 3 the two sets of orifices 3, 4 have the same common point of intersection on the longitudinal axis of the jet it is quite possible for each set of orifices to have a different point of intersection on this axis.
A complete shrouded burner incorporating the jet illustrated in FIGS. 1 to 3, is shown in FIGS. 4 and 5. The jet is mounted into a metal socket 5 which is provided with an annular shoulder 6 for receiving a shroud 7. The vertical distance of the orifices below the highest point of .the shroud are of the order of 0.4 inch for orifices of 0.010 inch to 0.015 inch diameter and for the angles of divergence stated above.
It will be seen from FIGS. 4 and 5 that air flows over the lip of the shroud and between the divergent flames into the center of the coalesced region 9 and takes up the flow pattern illustrated by the arrows. The wall of the shroud 7 is at an angle to the longitudinal or vertical axis of the jet so that each flame passes in close proximity to the peripheral edge thereof. A certain amount of air flows over the lip of the shroud and down the inside of wall before being taken up by the ellipticalflame ring, the clearance between the flames and the lip controlling the amount of airflow. The dimensions of the cavity 10, which is of generally wedge-shaped section, formed between the flames and the wall of the shroud is also of importance since it is in this area that recirculation of the products of incomplete combustion occurs and the volume of the latter have to be related to the volume of the cavity for purposes of stabilization.
For the particular construction described the internal diameter of the shroud around the jet is 0.30 inch, the internal width at the top in the minor axis is 0.45 inch, and the internal length at the top in the major axis is 0.84 inch. The jet can be used with natural gas without flame lift at pressures of up to 12 inches water gauge and has well aerated flames.
The jet-described above produces a final flame shape which covers a generally elliptical area in plan view but for some applications, such as water heaters and central heating boilers which have open combustion chambers, a circular area is required. A preferred form of jet giving a final flame which is substantially circular in plan view, is illustrated in FIGS. 6 to 8. Four 0.0l3-inch diameter circular orifices 11 are formed in the hemispherical portion 12, of a jet 13. The portion 12 has an external radius of 0.105 inch and the angles between the longitudinal axis of adjacent orifices is 24 The angle between the longitudinal axis of each orifice and the longitudinal axis of the jet is 17. FIG. 8 illustrates thejet 13 mounted on a metal socket 14 provided with an annular projection 15 for receiving a shroud I6. The latter takes the form of an inverted truncated cone with an internal diameter around the jet of 0.30 inch, an internal diameter at the top of 0.55 inch, the top of the shroud being 0.40 inch above the apex of the jet. Jets with up to 12 orifices can be designed to produce circular plan flames. In general terms, it is desirable that the angle between the longitudinal axes of adjacent orifices falls between 20 and 30. In order to satisfy this condition, the angle between the longitudinal axis of each orifice and the longitudinal axis of the jet has to be in the range of 10 to 45 dependent upon the number of orifices used and their angle of divergence.
FIG. 8 shows the final flow pattern, indicated by arrows, and flame formation achieved by the shrouded burner. It will be seen that the burner again produces a coalesced flame portion and that reverse airflow is obtained between the flames themselves and between the flames and the peripheral edge of the wall of the shroud.
ln some applications, particularly gas fires in which the jet fires into box-type ceramic radiants of rectangular section, a thin flame is required in order to avoid flame impingement with consequent poor combustion or sooting. A jet 18 which produces a thin flame is shown in FIGS. 9 and 10, and has five orifices 19, the three inner ones being of 0.0125 inch diameter, and the two outer ones being of 0.0095 inch diameter,
formed in a single row across the central plane of a spherical projection 20. In one example, the external radius of the projection 20 is 0.1 10 inch and the angle between the longitudinal axes of adjacent orifices is 17. FIGS 11 to 13 illustrate the jet 18 mounted for a metal socket 21 provided with an annular projection 22 for receiving a shroud 23. Because in this case there is no lateral divergence of the flames, the side portions of the wall of the shroud 22 are parallel, as shown, or they may be slightly convergent, in order to regulate the flow of air into the shroud through the cleance between the lip and the flame and in order to contain the combustion products near to the flame base. The maximum width of the mouth of the shroud is 0.312 inch, the length is 1.007 inches and the tip of the jet is 0.570 inches below the uppermost point of the shroud.
ln another example of this type of jet the five orifices 19 are of slightly larger diameter, the three inner ones being 0.145 inches and the two outer ones 0.01 inches. In this case the external radius of the projection is 0.135 inches. The external radius of the projection 20 must be adjusted in accordance with orifice diameter in order to maintain a fairly constant ratio between orifice diameter and orifice center spacing. The dimensions of the shroud, for this example are, width of mouth 0.312, length of mouth 1.100 inches and the tip of the jet is 0.570 inches below the uppermost point of the shroud.
In both examples of the jet 18 described the five orifices could all be of equal size or they could all be different since the relative diameters only affect the overall flame shape.
The depth of the shroud 23 is slightly greater in this case because the angle of divergence of the separate flames is less than for the burners shown in FIGS. 1 to 8, and the actual point of divergence 24 of adjacent flames is therefore somewhat further from the orifices. This lower degree of divergence is necessary to give more coalescence near to the flame base and hence more mutual stabilization. FIGS. 11 and 12 illustrate the flame formation and the airflow pattern achieved. It will be seen that reverse airflow still occurs between the outer surface of the flames and the lip of the shroud and the products of incomplete combustion are retained for recirculation in the wedge-shaped gap 25 formed between the flame and the wall of the shroud.
Other applications require a large plan area to be heated by a small number of jets, or as in the case of a cooker oven, one jet to produce uniform heat over a long surface. These applications require a jet which gives a wide flame and such a jet 26 is shown in FIGS. 14 and 15. The jet 26 is provided with a linear or row of 11 orifices 27 of 0.0117 inches diameter formed in a spherically contoured projection 28 of external radius 0.093 inches with an angle of 18 between the axes of adjacent orifices. A complete shrouded burner incorporating the jet 26 is shown in FIGS. 16 to 18. The jet is mounted on a metal socket 29 provided with an annular shoulder 30 for receiving a shroud indicated generally at 31. The shroud consists of two substantially semicircular parallel walls 32 of 0.687 inches radius and have a separation of between 0.260 inches and 0.312 inches depending on the orifice diameters which are approximately 0.0117 inches. The walls may be parallel as shown or slightly convergent and are closed at the bottom by a pair of flat plates 33 which project from the jet at an angle of about 10 below the horizontal FIGS. 16 an 1? illustrate the final flame formation and the airflow pattern depicted by the arrows. The principle of reverse airflow counter to the flow of gas and over the lips of the walls of the shroud again applies with the products of combustion being retained for recirculation in the wedge-shaped gaps 35 formed between the flame and the walls of the shroud. Where a still higher heat concentration is required a modified jet, now shown, of the same general form as the jet 26 can be used with a double row of orifices with an angle of 24 between the longitudinal axes of the orifices in each row with the shroud suitably modified, and with the angles of divergence between the longitudinal axes of the adjacent orifices increased to 25 to allow airflow between the two rows of flame.
A further development, which is not illustrated, is to have 20 0.012 inches diameter orifices around the circumference of a jet of 0.18 inches diameter with an angle of 18 between the axes of adjacent orifices and with these axes at to the axis of the jet, so that all flames project horizontally from the jet. A circular disc 1.25 inches diameter is positioned below the onfices and another above the orifices with the surfaces of both flaring away from the jet at angles of 15 below and above the horizontal respectively.
It will be understood that the orifice dimensions of the various embodiments described above can be modified where necessary. As the orifices are reduced in size, the rate of flow of gas will decrease as will the volume of combustion products produced on ignition, and hence for the purpose of mutual stabilization the orifice spacing has to be reduced. Conversely, with larger orifices, the orifice spacing has to be increased. Furthemtore, it will be understood that the orifices for each jet described may all be the same size or they may be all different, change in orifice dimensions only affecting flame length and hence overall flame shape. Moreover, the number of orifices and their disposition one to another can be varied in order to obtain different overall flame shapes. The induced air flow and the volume of the combustion products vary according to on'fice diameter and the flow of gas therefrom and consequently the dimensions of the jets and shrouds must be varied correspondingly. The longitudinal axes of all the orifices or sets of orifices of each embodiment described above diverge from a common origin. However, diverging flames can also be obtained by having orifices with parallel axes formed in a thin section or diaphragm as illustrated in FIGS. 19 and 20. The jet has a cylindrical wall 40 surmounted by a frustum of a cone 41, the orifices 42 being formed in the conical surface and being arranged parallel to the axis of the jet. The angle at which the flames leave the jet can be altered by altering the thickness of the conical or diaphragm portion. This method of manufacture of jets would be particularly applicable to the jet illustrated in FIGS. 6 and 7.
In all the embodiments described above the top or lip of the shroud is contoured so that at maximum design gas pressure the point of divergence of adjacent flames is level with the lip, and that at minimum design gas pressure the pint of divergence is slightly below the level of the lip. With this arrangement the burners provide stable nonaerated flames with natural gas at operating pressures of approximately 6-10 inches water gauge.
In all the embodiments described above the dimensions specified are those which produce stable flames with methane at operating pressures of between 6 and 10 inches water gauge. There are several forms of natural gas containing methane, however, with various heating values and there are also various possible substitute gases which can be used in an emergency. Consequently some tolerance on all the dimensions specified is required, and it is suggested that a figure of i 25 percent is not unreasonable.
ln all the burners described the production of closely spaced diverging flames which coalesce over a part of their length only, achieves both mutual stabilization and satisfactory aeration of the flames as a whole. Furthermore, the divergence of the flames also induces reverse airflow which assists ignition, and with a cluster or closed ring of flames helps to contain the combustion products within the cluster. Furthermore, the use of a shroud or cup around the coalesced region of the flames protects them from direct airflow and contains the products of combustion near to the reaction zone so that they may be reentrained thereby accelerating the combustion process.
Various forms of jets and burners have been described but it will be evident that other designs based upon the principles listed in the foregoing paragraph are possible. There is also no reason why these principles should not be applied in the design of so-called ribbon burners, for example, in which orifices may be formed in projections on the upper face of a continuous channel member, and a shroud of section appropriate to the required flame shape is placed around each projection. Furthermore, the jets described can also be used in the design of aerated burners in which case the orifices would have to be rather larger to allow for the increased flow arising from premixing of air with the gas before it issues from the orifices.
We claim:
1. A shrouded burner including in combination a gas jet having a plurality of gas orifices lying on a common ellipse producing, in use, diverging flames which coalesce only in the region of the gas orifices, and a shroud having at least one wall, said at least one wall protecting the gas'orifices from direct airflow and being shaped and dimensioned so that a given flame passes in close proximity to the peripheral edge thereof, said peripheral edge being contoured so that at the maximum design gas pressure the point of divergence of adjacent flames is level with said edge and at minimum design gas pressure the point of divergence of adjacent flames is slightly below said edge.
2. A burner as claimed in claim 11 in which the walls of the shroud are generally elliptical.
3. A burner as claimed in claim 2 in which two sets of orifices are provided the longitudinal axes of the orifices in each set having a ditferent common point of intersection on the longitudinal axis of the jet.
4. A shrouded burner for providing stable nonaerated flames with natural gas at operating pressures of approximately 6 to 10 inches water gauge including in combination a gas jet having a plurality of gas orifices producing, in use, diverging flames which coalesce only in the region of the gas orifices, and a shroud for protecting the gas orifices from direct airflow in which:
two sets of orifices are provided which lie on a common ellipse and which have diameters of 0.010 inches to 0.015 inches, the longitudinal axis of each orifice of one of the sets lying at an angle of the order of to to the 1on gitudinal axis of the jet, and the longitudinal axis of each orifice of the other of the sets lying at an angle of the order of 30 to 40 to the longitudinal axis of thejet and in which the walls of the shroud are generally elliptical, the shroud having an internal diameter around the jet of the order of 0.30 inches (5 percent), an internal wid h at the top in the minor axis of the order to 0.45 inch (5 percent), and an internal length at the top in the major axis of the order of 0.84 inch (5 percent), the distance of the orifices below the highest point of the shroud being of the order of 0.40 inch (5 percent), whereby a given flame passes in close proximity to the peripheral edge of the shroud, and whereby at the maximum design gas pressure the point of divergence of adjacent flames is level with said edge, and at minimum design gas pressure the point of divergence of adjacent flames is slightly below said edge.
5. A shrouded burner for providing stable nonaerated flames with natural gas at operating pressures of approximately 6 to 10 inches water gauge including in combination a gas jet having a plurality of gas orifices producing, in use, diverging flames which coalesce only in the region of the gas orifices, and a shroud protecting the gas orifices from direct airflow in which:
the orifices lie on a common circle and have diameters of the order of 0.013 inch (5 percent), the angle between the longitudinal axis of adjacent orifices being of the order of 20 to 30 and that between the longitudinal axis of each orifice and the longitudinal axis of the jet being of the order of 10 to 45, and in which the shroud is in the form of an inverted truncated cone the shroud having'an internal diameter around the jet of the order of 0.30 inch (5 percent) and an internal diameter at the top of the order of 0.55 inch (5 percent), the distance of the orifices below the highest point of the shroud being of the order of 0.40 inch (5 percent), whereby a given flame passes in close proximity to the peripheral edge of the shroud and whereby at the maximum design gas pressure the point of divergence of adjacent flames is level with said edge and at minimum design gas pressure the point of divergence of adjacent flames is slightly below said edge.
6. A shrouded burner for providing stable nonaerated flames with natural gas at operating pressures of approximately 6 to 10 inches water gauge including in combination a gas jet having a plurality of gas orifices producing, in use, diverging flames which coalesce only in the region of the gas orifices, and a tubular shroud for protecting the gas orifices from direct airflow in which:
the orifices line in common plane containing the longitudinal axis of the jet and have diameters of 0.0095 inch to 0.0145 inch (5 percent), the angle between the longitudinal axis of adjacent orifices being of the order of 17, and in which a pair of opposed walls of the shroud are substantially planar in configuration, the walls being parallel or slightly upwardly convergent with respect to the longitudinal plane containing the orifices, the maximum width of the mouth of the shroud being of the order of 0.312 inch (5 percent), the length of the mouth being of the order of 1.077 inch to 1.100 inch (5 percent), and the tip of the jet being of the order of 0.570 inch (5 percent) below the uppermost point of the shroud, whereby a given flame passes in close proximity to the peripheral edge of the shroud and whereby at the maximum design gas pressure the point of divergence of adjacent flames is level with said edge and at minimum design gas pressure the point of divergence of adjacent flames is slightly below said edge.
7. A shrouded burner as claimed in claim 6 in which: there are five orifices, the three inner orifices having a diameter of the order of 0.0125 inch (5 percent) and the two outer orifices having a diameter of the order of 0.0095 inch (5 percent).
8. A shrouded burner as claimed in claim 6 in which:
there are five orifices, the three inner orifices having a diameter of the order of 0.0145 inch (5 percent) and the 'two outer orifices having a diameter of the order of 0.01 15 inch (5 percent).
9. A shrouded burner for providing stable nonaerated flames with natural gas at operating pressures of approximately 6 to 10 inches water gauge including in combination a gas jet having a plurality of gas orifices producing, in use, diverging flames which coalesce only in the region of the gas orifices, and a shroud for protecting the gas orifices from direct airflow, in which:
the orifices lie in a common plane containing the longitudinal axis of the jet and have diameters of the order of 0.0117 inch (5 percent), the angle between the longitudinal axis of adjacent orifices being of the order of 18 and in which the shroud consists of two substantially semicircular substantially parallel walls of the order of 0.687 inch (5 percent) radius and having a separation of the order of between 0.260 and 0.312 inch (5 percent), whereby a given flame passes in close proximity to the peripheral edges of said walls and whereby at the maximum design gas pressure the point of divergence of adjacent flames is level with said edges and at minimum design gas pressure the point of divergence of adjacent flames is slightly below said edge.
10. A shrouded burner as claimed in claim 9 in which:
the walls are closed at the bottom by a pair of flat plates which project from the jet at an angle of about 10 below the horizontal.
11. A shrouded burner including in combination a gas jet having a cylindrical wall surmounted by a frustum of a cone, a plurality of gas orifices being formed in the conical surface and being arranged parallel to the longitudinal axis of the jet so as to produce, in use, diverging flames which coalesce only in the region of the gas orifices, and a shroud having at least one wall, said at least one wall protecting the gas orifices from direct airflow and being shaped and dimensioned so that a given flame passes in close proximity to the peripheral edge thereof, said peripheral edge being contoured so that at the maximum design gas pressure the point of divergence of adjacent flames is level with said edge and at minimum design gas pressure the point of divergence of adjacent flames is slightly below said edge.
12. A shrouded burner including in combination a gas jet having a plurality of gas orifices lying in a common plane containing the longitudinal axis of the jet and producing, in use, diverging flames which coalesce only in the region of the gas orifices, and a shroud having at least one wall, said at least one wall protecting the gas orifices from direct airflow and being shaped and dimensioned so that a given flame passes in close proximity to the peripheral edge thereof, said peripheral edge being contoured so that at the maximum design gas pressure the point of divergence of adjacent flames is level with said edge and at minimum design gas pressure the point of divergence of adjacent flames is slightly below said edge.
13. A burner as claimed in claim 12 in which sald shroud has a pair of opposed walls, said walls being substantially planar in configuration and being parallel or slightly upwardly convergent with respect to the longitudinal plane containing the orifices.
14. A burner as claimed in claim 12 in which the shroud consists of two substantially semicircular plane walls, said walls being parallel or slightly upwardly convergent with respect to the longitudinal plane containing the orifices.
15. A burner as claimed in claim 14 in which the walls are closed at the bottom by a pair of flat plates.
I k i i 1 Disclaimer 3,630,649.John Hancock, Leeds, and Albert Westewman, Normanton, England. SHROUDED GAS BURNERS AND JETS THEREFOR. Patent dated Dec. 28, 1971. Disclaimer filed May 4:, 1971, by the assignee, Geo. Bray de Company Limited.
Hereby disclaims the portion of the term of the patent subsequent to Apr. 22 1986.
[Ofiioial Gazette Apm'l 18, 1972.

Claims (15)

1. A shrouded burner including in combination a gas jet having a plurality of gas orifices lying on a common ellipse producing, in use, diverging flames which coalesce only in the region of the gas orifices, and a shroud having at least one wall, said at least one wall protecting the gas orifices from direct airflow and being shaped and dimensioned so that a given flame passes in close proximity to the peripheral edge thereof, said peripheral edge being contoured so that at the maximum design gas pressure the point of divergence of adjacent flames is level with said edge and at minimum design gas pressure the point of divergence of adjacent flames is slightly below said edge.
2. A burner as claimed in claim 1 in which the walls of the shroud are generally elliptical.
3. A burner as claimed in claim 2 in which two sets of orifices are provided the longitudinal axes of the orifices in each set having a different common point of intersection on the longitudinal axis of the jet.
4. A shrouded burner for providing stable nonaerated flames with natural gas at operating pressures of approximately 6 to 10 inches water gauge including in combination a gas jet having a plurality of gas orifices producing, in use, diverging flames which coalesce only in the region of the gas orifices, and a shroud for protecting the gas orifices from direct airflow in which: two sets of orifices are provided which lie on a common ellipse and which have diameters of 0.010 inches to 0.015 inches, the longitudinal axis of each orifice of one of the sets lying at an angle of the order of 15* to 20* to the longitudinal axis of the jet, and the longitudinal axis of each orifice of the other of the sets lying at an angle of the order of 30* to 40* to the longitudinal axis of the jet and in which the walls of the shroud are generally elliptical, the shroud having an internal diameter around the jet of the order of 0.30 inches ( + or - 25 percent), an internal width at the top in the minor axis of the order of 0.45 inch ( + or - 25 percent), and an internal length at the top in the major axis of the order of 0.84 inch ( + or - 25 percent), the distance of the orifices below the highest point of the shroud being of the order of 0.40 inch ( + or - 25 percent), whereby a given flame passes in close proximity to the peripheral edge of the shroud, and whereby at the maximum design gas pressure the point of divergence of adjacent flames is level with said edge, and at minimum design gas pressure the point of divergence of adjacent flames is slightly below said edge.
5. A shrouded burner for providing stable nonaerated flames with natural gas at operating pressures of approximately 6 to 10 inches water gauge including in combination a gas jet having a plurality of gas orifices producing, in use, diverging flames which coalesce only in the region of the gas orifices, and a shroud protecting the gas orifices from direct airflow in which: the orifices lie on a common circle and have diameters of the order of 0.013 inch ( + or - 25 percent), the angle between the longitudinal axis of adjacent orifices being of the order of 20* to 30* and that between the longitudinal axis of each orifice and the longitudinal axis of the jet being of the order of 10* to 45*, and in which the shroud is in the form of an inverted truncated cone the shroud having an internal diameter around the jet of the order of 0.30 inch ( + or - 25 percent) and an internal diameter at the top of the order of 0.55 inch ( + or - 25 percent), the distance of the orifices below the highest point of the shroud being of the order of 0.40 inch ( + or - 25 percent), whereby a given flame passes in close proximity to the peripheral edge of the shroud and whereby at the maximum dEsign gas pressure the point of divergence of adjacent flames is level with said edge and at minimum design gas pressure the point of divergence of adjacent flames is slightly below said edge.
6. A shrouded burner for providing stable nonaerated flames with natural gas at operating pressures of approximately 6 to 10 inches water gauge including in combination a gas jet having a plurality of gas orifices producing, in use, diverging flames which coalesce only in the region of the gas orifices, and a tubular shroud for protecting the gas orifices from direct airflow in which: the orifices lie in a common plane containing the longitudinal axis of the jet and have diameters of 0.0095 inch to 0.0145 inch ( + or - 25 percent), the angle between the longitudinal axis of adjacent orifices being of the order of 17*, and in which a pair of opposed walls of the shroud are substantially planar in configuration, the walls being parallel or slightly upwardly convergent with respect to the longitudinal plane containing the orifices, the maximum width of the mouth of the shroud being of the order of 0.312 inch ( + or - 25 percent), the length of the mouth being of the order of 1.077 inch to 1.100 inch ( + or - 25 percent), and the tip of the jet being of the order of 0.570 inch ( + or - 25 percent) below the uppermost point of the shroud, whereby a given flame passes in close proximity to the peripheral edge of the shroud and whereby at the maximum design gas pressure the point of divergence of adjacent flames is level with said edge and at minimum design gas pressure the point of divergence of adjacent flames is slightly below said edge.
7. A shrouded burner as claimed in claim 6 in which: there are five orifices, the three inner orifices having a diameter of the order of 0.0125 inch ( + or - 25 percent) and the two outer orifices having a diameter of the order of 0.0095 inch ( + or - 25 percent).
8. A shrouded burner as claimed in claim 6 in which: there are five orifices, the three inner orifices having a diameter of the order of 0.0145 inch ( + or - 25 percent) and the two outer orifices having a diameter of the order of 0.0115 inch ( + or - 25 percent).
9. A shrouded burner for providing stable nonaerated flames with natural gas at operating pressures of approximately 6 to 10 inches water gauge including in combination a gas jet having a plurality of gas orifices producing, in use, diverging flames which coalesce only in the region of the gas orifices, and a shroud for protecting the gas orifices from direct airflow, in which: the orifices lie in a common plane containing the longitudinal axis of the jet and have diameters of the order of 0.0117 inch ( + or - 25 percent), the angle between the longitudinal axis of adjacent orifices being of the order of 18* and in which the shroud consists of two substantially semicircular substantially parallel walls of the order of 0.687 inch ( + or - 25 percent) radius and having a separation of the order of between 0.260 and 0.312 inch ( + or - 25 percent), whereby a given flame passes in close proximity to the peripheral edges of said walls and whereby at the maximum design gas pressure the point of divergence of adjacent flames is level with said edges and at minimum design gas pressure the point of divergence of adjacent flames is slightly below said edge.
10. A shrouded burner as claimed in claim 9 in which: the walls are closed at the bottom by a pair of flat plates which project from the jet at an angle of about 10* below the horizontal.
11. A shrouded burner including in combination a gas jet having a cylindrical wall surmounted by a frustum of a cone, a plurality of gas orifices being formed in the conical surface and being arranged parallel to the longitudinal axis of the jet so as to produce, in use, diverging flames whiCh coalesce only in the region of the gas orifices, and a shroud having at least one wall, said at least one wall protecting the gas orifices from direct airflow and being shaped and dimensioned so that a given flame passes in close proximity to the peripheral edge thereof, said peripheral edge being contoured so that at the maximum design gas pressure the point of divergence of adjacent flames is level with said edge and at minimum design gas pressure the point of divergence of adjacent flames is slightly below said edge.
12. A shrouded burner including in combination a gas jet having a plurality of gas orifices lying in a common plane containing the longitudinal axis of the jet and producing, in use, diverging flames which coalesce only in the region of the gas orifices, and a shroud having at least one wall, said at least one wall protecting the gas orifices from direct airflow and being shaped and dimensioned so that a given flame passes in close proximity to the peripheral edge thereof, said peripheral edge being contoured so that at the maximum design gas pressure the point of divergence of adjacent flames is level with said edge and at minimum design gas pressure the point of divergence of adjacent flames is slightly below said edge.
13. A burner as claimed in claim 12 in which saId shroud has a pair of opposed walls, said walls being substantially planar in configuration and being parallel or slightly upwardly convergent with respect to the longitudinal plane containing the orifices.
14. A burner as claimed in claim 12 in which the shroud consists of two substantially semicircular plane walls, said walls being parallel or slightly upwardly convergent with respect to the longitudinal plane containing the orifices.
15. A burner as claimed in claim 14 in which the walls are closed at the bottom by a pair of flat plates.
US846832A 1968-08-20 1969-08-01 Shrouded gas burners and jets therefor Expired - Lifetime US3630649A (en)

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Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3948593A (en) * 1972-02-04 1976-04-06 Frymaster Corporation Combustion method using gas flow interaction and heat reflection
US4573907A (en) * 1984-11-07 1986-03-04 Maxon Corporation Low oxygen and low pressure drop burner
US4815426A (en) * 1987-02-26 1989-03-28 Henschel Paul S Engine heater, small, portable
US5588831A (en) * 1994-06-23 1996-12-31 Nec Corporation Furnace system equipped with protected combustion nozzle used in fabrication of semiconductor device
US6196213B1 (en) * 1995-01-13 2001-03-06 Van Der Woude Meino Jan Barbecue table
US6478577B1 (en) * 2000-08-24 2002-11-12 Beckett Gas, Inc. Burner nozzle with curved head
US20020187446A1 (en) * 2001-06-07 2002-12-12 Wong Chi Lam Torch lighter for cigar
US20060101662A1 (en) * 2004-11-12 2006-05-18 Bsh Home Appliances Corporation Gas burner and air heater assembly for a gas clothes dryer
US20090061374A1 (en) * 2007-01-17 2009-03-05 De Jong Johannes Cornelis High capacity burner
US20220275927A1 (en) * 2021-02-26 2022-09-01 Armando Parra Control Means for Vortex Flame Device

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1498644A (en) * 1922-06-08 1924-06-24 Horace H Clark Gas burner
US2513087A (en) * 1949-09-06 1950-06-27 Ferrel Gerald Wellington Gas burner with internal fuel distributor
US2646113A (en) * 1948-04-20 1953-07-21 Blackman Keith Ltd Combustion cell gas burner
US3204684A (en) * 1963-01-03 1965-09-07 Zink Co John Burner head for gaseous fuel
US3439997A (en) * 1966-10-21 1969-04-22 Bray & Co Ltd Geo Post-aerated gas jets

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1498644A (en) * 1922-06-08 1924-06-24 Horace H Clark Gas burner
US2646113A (en) * 1948-04-20 1953-07-21 Blackman Keith Ltd Combustion cell gas burner
US2513087A (en) * 1949-09-06 1950-06-27 Ferrel Gerald Wellington Gas burner with internal fuel distributor
US3204684A (en) * 1963-01-03 1965-09-07 Zink Co John Burner head for gaseous fuel
US3439997A (en) * 1966-10-21 1969-04-22 Bray & Co Ltd Geo Post-aerated gas jets

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3948593A (en) * 1972-02-04 1976-04-06 Frymaster Corporation Combustion method using gas flow interaction and heat reflection
US4573907A (en) * 1984-11-07 1986-03-04 Maxon Corporation Low oxygen and low pressure drop burner
US4815426A (en) * 1987-02-26 1989-03-28 Henschel Paul S Engine heater, small, portable
US5588831A (en) * 1994-06-23 1996-12-31 Nec Corporation Furnace system equipped with protected combustion nozzle used in fabrication of semiconductor device
US6196213B1 (en) * 1995-01-13 2001-03-06 Van Der Woude Meino Jan Barbecue table
US6478577B1 (en) * 2000-08-24 2002-11-12 Beckett Gas, Inc. Burner nozzle with curved head
US20020187446A1 (en) * 2001-06-07 2002-12-12 Wong Chi Lam Torch lighter for cigar
US20060101662A1 (en) * 2004-11-12 2006-05-18 Bsh Home Appliances Corporation Gas burner and air heater assembly for a gas clothes dryer
US7213348B2 (en) 2004-11-12 2007-05-08 Bsh Home Appliances Corporation Gas burner and air heater assembly for a gas clothes dryer
US20090061374A1 (en) * 2007-01-17 2009-03-05 De Jong Johannes Cornelis High capacity burner
US20220275927A1 (en) * 2021-02-26 2022-09-01 Armando Parra Control Means for Vortex Flame Device
US11852319B2 (en) * 2021-02-26 2023-12-26 Armando Parra Control means for vortex flame device

Also Published As

Publication number Publication date
GB1203489A (en) 1970-08-26
FR2015966A1 (en) 1970-04-30
DE6931621U (en) 1970-01-02
NL6912271A (en) 1970-02-24
DE1940717A1 (en) 1970-04-02
BE737746A (en) 1970-02-02

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