GB2062840A - High intensity burner - Google Patents

Abstract

A high intensity gas burner apparatus of the type having a substantially cylindrical combustion chamber 22, means 26 for introducing combustion air into the combustion chamber in a swirling motion, and a fuel gas inlet nozzle 34 for introducing fuel gas into the combustion chamber. The fuel gas inlet nozzle is positioned with respect to the combustion chamber, whereby fuel gas is introduced into the combustion chamber at one or more locations which are offset from the axis of the vortex created by the swirling combustion air therein. <IMAGE>

Description

SPECIFICATION High intensity gas burner apparatus The present invention relates generally to high intensity gas burner apparatus.

Gas burner apparatus known as high intensity burners are those in which intimate mixing of fuel gas and combustion air takes place within the burner, and as a result, the combustion reaction is substantially confined within the burner and a high velocity stream of hot combustion gases exits the burner. Typical gas burner apparatus of this type are disclosed in U.S. Patent Nos. 3,265,113 and 3,720,495, both of which are owned by the assignee of the present invention, and U.S. Patent No. 3,485,566.

In such prior apparatus, the combustion air is introduced into a combustion chamber in a swirling motion whereby the combustion air generates a vortex at the rearward area of the combustion chamber. The fuel gas is introduced into the combustion chamber along the axis of the vortex created in the combustion chamber. While such burners have been operated successfully, the introduction of the fuel gas at the combustion air vortex causes the flame front within the burners to pulsate, which in turn, brings about somewhat unstable combustion, vibration and a high noise level.

According to the present invention we provide a high intensity gas burner apparatus having an elongate combustion chamber, means for introducing combustion air into the combustion chamber in a swirling motion, to provide a vortex of combustion air and a fuel gas inlet nozzle for introducing fuel gas into the combustion chamber, and into the vortex created by the swirling combustion air introduced therein, the fuel gas inlet being positioned with respect to the combustion chamber, whereby the fuel gas is introduced into the swirling combustion air within the combustion chamber at one or more locations offset from the axis of the vortex created thereby.

Such a construction brings about a more complete mixing of the fuel gas and combustion air whereby pulsation of the flame front within the apparatus is greatly reduced. This in turn brings about more stable combustion of the fuel-air mixture resulting in lower carbon monoxide emissions from the burner apparatus, shorter flame lengths, and a substantial reduction in the noise level of the burner during operation.

A preferred embodiment of apparatus according to the invention comprises a hollow outer shell having a forward end and a rearward end, a front wall closing the forward end of said outer shell, a back wall closing the rearward end of said outer shell, a hollow inner liner having a forward end and a rearward end supported within said outer shell and positioned substantially coaxially therein, to provide an air passageway between the outer shell and the inner liner, the forward end of said inner liner extending through said front wall and the rearward end of said inner liner being spaced a distance from said back wall, a combustion air inlet in said outer shell for admitting air into said air passageway, whereby the air is caused to swirl in said air passageway around said inner liner to produce a combustion air vortex in said inner liner, a fuel says inlet nozzle extending through said back wall and into the interior of said inner liner, said fuel gas inlet nozzle having one or more open forward ends for discharging one or more jets of fuel gas into said inner liner between the axis of said inner liner and the interior wall surface thereof, whereby said one or more jets are offset from the axis of the vortex.

In order that the invention may more readily be understood, the following description is given, merely by way of example, reference being made to the accompanying drawings, in which: Figure 1 is a sectional side elevational view of one form of gas burner apparatus constructed in accordance with the present invention; Figure 2 is a sectional view taken along line 2-2 of Figure 1; Figure 3 is a sectional view taken along line 3-3 of Figure 1; Figure 4 is an enlarged partial sectional view of the rearward end of the apparatus of Figure 1; Figure 5 is an enlarged partial sectional view similar to Figure 4 but illustrating a modified form of the apparatus of the present invention; and Figure 6 is an enlarged partial sectional view taken along line 6-6 of Figure 5.

Referring now to Figures 1 4, the illustrated apparatus 10 includes a hollow, substantially cylindrical outer shell 12 having a forward end 14 connected to a front wall 1 8 and a rearward end 16 connected to a back wall 20. An inner liner 22 which forms a combustion chamber within the apparatus 10 is disposed within the outer shell 12 and spaced a distance therefrom about the entire outer periphery of the inner liner whereby an annular air passageway 24 is formed between the inner liner 22 and the outer shell 12.

A volute-shaped air inlet 26 is formed in a portion of the outer shell 12 for directing combustion air into the air passageway 24, so that combustion air flowing therethrough is directed generally tangentially to the inner periphery of the outer shell 12 causing the air to follow a helical path through the passageway 24 and a swirling motion to be imparted thereto. The combustion air can be atmospheric air, oxygen, or a mixture of atmospheric air and oxygen.

In the illustrated construction the rearward portion of the outer shell 12 and the rearward portion of the inner liner are of frusto-conical shape converging towards the rearward end 1 6.

The forward portion of the inner liner 28 is preferably of frusto-conical shape converging towards the forward end 30 thereof which extends through the front wall 1 8 of the outer shell 12. On the other hand, the rearward end 28 of the inner line 22 is spaced a distance from the back wall 20 of the outer shell 12 whereby the combustion air flowing through the passageway 24 enters the inner liner 22 by way of the open end 28 of the inner liner. As shown in Figure 2, the forward end portion of the inner liner 22 can converge in a manner such that an elongated narrow outlet 32 is formed at the forward end 30 thereof or the outlet 32 can be circular. The inner liner 22 and outer shell 12 are also preferably positioned coaxially.

Extending through and sealingly attached to the back wall 20 of the outer shell 12 is a fuel gas inlet nozzle. The back wall 20 is preferably removably connected to the outer shell 12 by a flange connection and the fuel gas inlet nozzle includes a flange for connection to a source of pressurized fuel gas by appropriate piping. In a like manner, the combustion air inlet 26 of the outer shell 12 includes a flange for connection to a source of pressurized combustion air.

The forward open end 36 of the nozzle 34 is positioned within the rear end of liner 22 and an interior wall surface thereof. While the nozzle 34 can take a variety of configurations, in the form illustrated in Figures 1-4, it includes a rearward cylindrical section 38 connected to a forward elbow section 40 by a forwardly converging frusto-conical section 42. In this form, the rearward cylindrical section 38 and frusto-conical section 42 are positioned coaxially with the inner liner 22 and outer shell 12 and the elbow section 40 positions the open end 36 of the nozzle 34 at a location between the axis of the inner liner 22 and a wall surface thereof. In addition, the open end 36 of the nozzle 34 is preferably positioned so that fuel gas is discharged from the nozzle 34 in a direction towards an inside wall surface of the inner liner 22.A plurality of air inspiration orifices 44 are disposed in the elbow section 40 of the nozzle 34, preferably adjacent the open end 36 thereof. An ignition assembly 46 which, in one form, can be a sparkplug-type ignition device is connected through the back wall 20 of the outer shell 12 in a manner such that the operating end 48 thereof is positioned adjacent the open end 36 of the nozzle 34.

In operation of the apparatus 10, combustion air is introduced into the air passageway 24 by way of the air inlet connection 26 of the outer shell 12 and follows a helical path through the air passageway 24 to the rearward end 1 6 of the outer shell 12. This imparts a swirling motion to the air and upon reaching the rearward end 1 6 of the outer shell 12, the combustion air enters the interior of inner liner 22 by way of the open end 28 thereof, creating a coaxially positioned vortex in the area between the rearward end 28 of the inner liner 22 and the back wall 20 of the outer shell 12. Fuel gas is introduced into the interior of the inner liner 22 at a location which is offset from the axis of the thus created vortex, that is, as illustrated, at a location within the inner liner 22 offset from the axis thereof.The fuel gas conducted to the nozzle 34 is under pressure and is emitted from the open end 36 of the elbow section 40 thereof in a high velocity jet which impinges upon an inside wall surface of the inner liner 22 and is thoroughly mixed with the swirling combustion air flowing through the inner liner 22 at a location offset from the vortex created by the combustion air. The resulting mixture of combustion air and fuel gas is combusted substantially within the inner liner 22 and hot products of combustion exit the inner liner 22 by way of the forward open end 30 thereof. The air inspiration orifices 44 disposed in the fuel gas inlet nozzle 34 inspirate primary air into the fuel gas flowing through the nozzle 34 prior to the ignition of the fuel gas thereby contributing to the stable combustion of the combustion air-fuel gas mixture within the inner liner 22.

As stated above, because the fuel gas is introduced into the inner liner 22 in high velocity jet at a location offset from the vortex created by the swirling combustion air within the apparatus 10, more complete mixing of the combustion air and fuel gas is achieved and pulsation of the flame front within the inner liner 22 is substantially reduced as compared to prior high intensity gas burner apparatus. This brings about more stable combustion which in turn lowers carbon monoxide emissions from the apparatus 10, shortens the flame length produced, and greatly reduces the noise level during operation of the apparatus 1 0.

In addition, because the fuel gas is introduced into the inner liner 22 in a high velocity jet and is not introduced into the vortex created by the swirling combustion air, the possibility of flash-backs during start-up and operation of the burner apparatus 1 0 is substantially reduced.

Referring now to Figures 5 and 6, a modified construction of apparatus is illustrated, which is the same as the apparatus 10 described above, except that instead of the nozzle 34, a nozzle 62 of different configuration is substituted therefor.

Thus, the apparatus 60 includes an outer shell 64, a back wall 66, an inner liner 68 and a spark igniter 70 which correspond to the parts 12, 20, 22 and 46 respectively of the apparatus 10.

The fuel gas inlet nozzle 62 differs from the fuel gas inlet nozzle 34 of the apparatus 10 in that it does not include a frusto-conical section, and instead of a forward elbow section, it includes a forward tee section 72 having a pair of opposite openings 74 and 76 for discharging fuel gas. The forward tee section 72 of the nozzle 62 is connected to a cylindrical section 78 which is sealingly attached through the back wall 66 and includes a flange 80 for connection to appropriate piping and to a source of pressurized fuel gas. The nozzle 62 can include a plurality of air inspiration orifices positioned adjacent the openings 74 and 76 of the forward tee section 72, and as illustrated in Figures 5 and 6, the nozzle 62 is preferably positioned coaxially with the inner liner 68.

The operation of the apparatus 60 is similar to the operation of the apparatus 1 0, the difference being that the fuel gas conducted to the nozzle 62 under pressure is discharged into the interior of the inner liner 68 by way of the open ends 74 and 76 of the section 72 thereof. The fuel gas is emitted from the open ends 74 and 76 in the form of two jets which impinge on inside wall surfaces of the inner liner 68 and are thoroughly mixed with the swirling combustion air flowing through the inner liner 68. As in the operation of the apparatus 10, the resulting mixture of combustion air and fuel gas is combusted substantially within the inner liner 68 of the apparatus 60 and hot products of combustion exit the inner liner by way of a forward open end thereof.More complete mixing of the combustion air and fuel gas is achieved and pulsation of the flame front within the inner liner 68 is substantially reduced as compared to prior high intensity gas burner apparatus wherein the fuel gas is introduced at the location of the vortex. This in turn produces the improved results mentioned above in connection with the apparatus 10.

Instead of the tangential inlet and the air passageway described above in connection with the apparatus 10 and 60, other structures can be utlized for imparting the swirling motion to the combustion air. For example, vanes or other similar structures can be connected to the inner liner 22 at the rearward end 28 thereof. In whatever technique and structure utilized for imparting a swirling motion to the combustion air and introducing it into the combustion chamber, the fuel gas inlet nozzle is positioned in accordance with the present invention to introduce one or more jets of fuel gas into the chamber in which combustion takes place at one or more locations between the axis of the chamber and a wall surface thereof offset from the axis of the vortex created by the swirling combustion air.

Claims (9)

1. A high intensity gas burner apparatus having an elongate combustion chamber, means for introducing combustion air into the combustion chamber in a swirling motion, to provide a vortex of combustion air and a guel gas inlet nozzle for introducing fuel gas into the combustion chamber, and into the vortex created by the swirling combustion air introduced therein, the fuel gas inlet being positioned with respect to the combustion chamber, whereby the fuel gas is introduced into the swirling combustion air within the combustion chamber at one or more locations offset from the axis of the vortex created thereby.

2. A high intensity gas burner apparatus comprising a hollow outer shell having a forward end and a rearward end, a front wall closing the forward end of said outer shell, a back wall closing the rearward end of said outer shell, a hollow inner liner having a forward end and a rearward end supported within said outer shell and positioned substantially coaxially therein, to provide an air passageway between the outer shell and the inner liner, the forward end of said inner liner extending through said front wall and the rearward end of said inner liner being spaced a distance from said back wall, a combustion air inlet in said outer shell for admitting air into said air passageway, whereby the air is caused to swirl in said air passageway around said inner liner to produce a combustion air vortex in said inner liner, a fuel gas inlet nozzle extending through said back wall and into the interior of said inner liner, said fuel gas inlet nozzle having one or more open forward ends for discharging one or more jets of fuel gas into said inner liner between the axis of said inner liner and the interior wall surface thereof, whereby said one or more jets are offset from the axis of the vortex.

3. A burner apparatus according to Claim 2, wherein said inner liner includes a frusto-conical section converging towards the rearward end thereof and a frusto-conical section converging towards the forward end thereof, and wherein said outer shell is shaped such that the inner linear and the outer shell are coaxially positioned.

4. A gas burner apparatus according to Claim 1, 2 or 3, wherein said fuel gas inlet nozzle includes a plurality of air inspiration orifices disposed therein.

5. A gas burner apparatus according to any preceding Claim, wherein said fuel gas inlet nozzle includes a frusto-conical section converging towards the forward end thereof.

6. A gas burner apparatus according to any preceding Claim, wherein said fuel gas inlet nozzle includes a forward elbow section, whereby a jet of fuel gas is discharged therefrom at a location between the axis of the combustion chamber and an inside wall surface thereof.

7. A gas burner apparatus according to any one of Claims 1 to 5, wherein said fuel gas inlet nozzle includes a forward tee section, whereby a pair of opposite jets of fuel gas are discharged therefrom at locations between the axis of the combustion chamber and the inside surfaces thereof.

8. A high intensity gas burner apparatus substantially as hereinbefore described with reference to and as illustrated in Figures 1 to 4 of the accompanying drawings.

9. A high intensity gas burner apparatus according to Claim 8, modified substantially as hereinbefore described with reference to and as illustrated in Figures 5 and 6 of the accompanying drawings.