US3002553A

US3002553A - Gaseous fuel burner

Info

Publication number: US3002553A
Application number: US797984A
Authority: US
Inventors: Robert D Reed
Original assignee: John Zink Co
Current assignee: Zinklahoma Inc
Priority date: 1959-03-09
Filing date: 1959-03-09
Publication date: 1961-10-03
Anticipated expiration: 1978-10-03

Description

Oct. 3, 1961 R. D. REED GASEOUS FUEL BURNER Filed March 9, 1959 INVENTOR ROBERT D. REED GL JULABL United States Patent The present invention relates to .a burner head for gaseous fuel and more specifically pertains to means in association with the discharge orifice maintaining stable ignition of the fuel escaping therethrough and such means serves to provide flame retaining characteristics for the fuel delivered from the burner head.

The prior art includes a .number of arrangements for maintaining kindling of gaseous fuel discharged through an outlet orifice or orifices and it is an object of the present invention to provide improvements in gaseous fuel burners wherein minor portions of the fuel are discharged through weep ports which causes thegaseous fuel escaping therethrough to move circum-ferentially of the burner head for mixture with limited quantities of secondary air to provide for stable burning of the fuel. escaping through the main discharge orifice whereby the burner head functions satisfactorily as a pilot burner. I a

A more detailed object of the invention is to provide an annular member disposed about the forward end of the discharge nozzle for a .gas burner with the assembly providing an annular chamber about thedownstream end of the discharge nozzle into which minor portions of the gaseous fuel is discharged for whirling movement in the annular chamber for mixture with secondary air admitted to the annular chamber in the vicinity of the downstream end of the main discharge nozzle whereby the burning fuel after escaping through the weep ports is shielded from the main flow of secondary air to provide extremely stable burning of the gaseous fuel in the vicinity of the downstream end of the annular chamber for kindling and rekindling the main fuel stream issuing from the main discharge orifice to provide the burner head with flame retaining characteristics.

Other objects and features of the invention will be ap preciated by those skilled in the combustion art as the present disclosure proceeds and upon consideration of the following detailed description taken with the accompanying drawing wherein an embodiment of the invention is disclosed.

In the drawing: 7

FIG. 1 is a side elevational view of a burner head embodying the invention and a portion of a conduit for supplying a gaseous fuel thereinto.

FIG. 2 is a sectional view on a larger scale and taken on the line 2-2 of FIG. 1.

FIG. 3 is a transverse section taken on the line 3--3 of FIG. 2.

FIG. 4 is a transverse sectional view taken on the line 4-4 of 'FIG. 2.

FIG. 5 is an elevational View of the downstream end of the burner head.

A burner head for gaseous fuel is shown in the drawing and the assembly includes an ignition cup member or annular member and a nozzle 11. The nozzle 11 is substantially cylindrical shaped and the upstream end is provided with internal threads for connection to a conduit 12 supplying a gaseous fuel into the nozzle 11. The burner head assembly while having particular utility for a gaseous fuel having primary air mixed therewith also functions well when supplied with other types of gaseous fuels.

The nozzle member 11 is provided with a discharge orifice 14 at its downstream end which may be of cylindrical configuration but of smaller diameter than the interior 16 of the nozzle member upstream of the discharge orifice 14. The fuel mixture in escaping through the orifice 14 creates a pressure drop. The pressure immediately downstream of the outlet end of the orifice 14 is less than the pressure within the nozzle member 11 upstream of the inlet end of the orifice 14. The lower pressure condition in the area immediately downstream of the exit end of the orifice 14 provides an operational feature of the burner assembly which will be evident as the disclosure proceeds. p

The annular or substantially cylindrical shaped wall of the nozzle member 11 is provided with a plurality of weep ports 17 as bestshown in FIGS. 2 and 3. The axis of each weep port 17 is disposed in a chord position relative to the cylindrical Wall 18 of the nozzle member and the axes of the weep ports 17 are disposed substantially tangentially of the wall 18. In the embodiment illustrated four weep ports 17 are provided but the number may be varied. The cross sectional area of the weep ports 17 in the aggregate is less than the area of the discharge orifice 14.

The burner assembly includesthe ignition cupor annular member 10 which has a cylindrical wall portion-21 having a larger diameter than the cylindrical Wall 18 which forms, a part of the nozzle member 11. The upstream end of the member 10 carries an inturned flange 22 which is adapted to seat against an annular shoulder 24 formed on the exterior of the nozzle member 11. An annular chamber 23 is'provided between the interior of the cylindrical wall 21 of the member 10 and the exterior of the cylindrical wall 18 into which minor portions of the gaseous fuel may escape through the weep ports 17. The ignition cup or annularmember 10 extends downstream beyond the corresponding end of the nozzle member 11 and the inner surface of the ignition cup adjacent the free end is of frusto-conical shape as indicated at 26. A plurality of radially disposed air inlet openings 27 are provided in the cylindricalwall portion 21 of the annular member. While four of such inlet openings 27 are j-pro-.

vided the number and the size may be varied for admitting secondary air to the presence of the gaseous fuel within the annularchamber 23. The axes of the ports 27 are desirably in a common transverse plane whichis. in the vicinity of the downstream end of the:nozzle mem-.

ber'll. I I In operation andwhen the gaseous fuel escapes through the weep ports 17 this gaseous fuel movescircumferen-v tially in the annular chamber 23 but advances slightly d ur ing each circular movement about the perimeter of the wall 18 because of the low pressure condition beyond the downstream end of the nozzle member 11. Combustion of the gaseous fuel in the annular chamber is facilitated by a limited quantity of air moving inwardly through the openings 27 and such movement of the air is promoted and maintained by the low pressure zone downstream of the discharge orifice 14. The burning gaseous fuel in the annular chamber 23 converges inwardly over all annular portions of the free end of the nozzle member 11 into the low pressure zone to provide burning fuel supplied by the weep ports 17 about the periphery of the fuel discharged through the orifice 14.

The gaseous fuel escaping through the weep ports 17 in its movement in the annular chamber 23 is circular and this whirling gaseous fuel moves in a helical manner and proceeds towards the zone Where it meets the air entering through the inlet openings 27 in the direction of the -arrows 29. Air also enters over the downstream end of the ignition cup or member 10 as indicated by the arrows 31 in FIG. 2. There is extremely stable burning of the gaseous fuel in the annular chamber 23 which provides for ignition and continued reignition of the fuel issuing through the discharge orifice 14 to form the main flame of the burner head. As a consequence of the circular movement of the gaseous fuel in the annular chamber 23 this fuel mixture essentially floats up to the zone where it meets air drawn into the member 10 by the low pressure area adjacent the discharge end of the orifice 14. The gaseous fuel escaping through the weep ports 17 burns stably because it moves downstream of the burner head atave'ry low velocity and because the secondary air moving through the openings 27 into mixture therewith is essentially nor foal to its forwarder downstream movement and because the secondary air moving in the direction of the arrows 31 is essentially counter-current to the downstream movement of the gaseous fuel in the annular space 23. The outwardly flared frusto-conical surface 26 of the member 1 is designed to be substantially parallel with the pe- 'riphery of the main flame so as to provide anannular open area between the periphery of the flame and the frustoconical portion 26 of the member to permit the counter- "c'urr'ent of air to move in the direction of the arrows 31.

While the invention has been described with reference to specific structural characteristics and with regard to one general overall assembly it will be appreciated that changes may be made in the combination as well as the details of the various elements. Such modifications and others may be made without departing from the spirit and scope of the invention as set forth in the appended claims.

What I claim and desire to secure by Letters Patent is:

1. A burner head for gaseous fuel comprising, a nozzle having a cylindrical wall and a discharge orifice in the downstream end thereof of smaller diameter than the internal diameter of said wall, an annular member carried by the downstream end of said nozzle embracing the exterior of the nozzle and providing an annular space between the exterior of the nozzle and the interior of said member, said cylindrical wall having a plurality of weep ports therein with the axis of each disposed in a chord position with respect to the cylindrical wall with all of said weep ports sloping in a similar direction in proceeding circumferentially of the nozzle, means for supplying gaseous fuel into said nozzle for escape through said discharge orifice with minor portions escaping through said Weep ports, and said annular member having circumferentially spaced openings therethrough in the vicinity of the downstream end of the nozzle member.

2. A burner head assembly for gaseous fuel comprising, a nozzle having a discharge orifice, means for supplying gaseous fuel into said nozzle for escape through said discharge orifice, an annular member embracing the downstream end of said nozzle in spaced relation providing an annular space between the exterior of the nozzle and the interior of said annular member, said nozzle having a plur'alityof weep ports therein upstream of said orifice with the axis of each disposed substantially tangentially of the nozzle and in similar directions in proceeding around said nozzle for discharging minor portions of the fuel into said annular space and circumferentially therein, and said member having circumferentially spaced openings therethrough in the vicinity of the downstream end of the noz- 216 member.

3. A burner head assembly for gaseous fuel comprising, a nozzle having a discharge orifice, means for supplying gaseous fuel into said nozzle for escape through said discharge orifice, an annular member embracing the downstream end of said nozzle in spaced relation providing an annular space between the exterior of the nozzle and the interior of said annular member, said nozzle having a plurality of weep ports therein upstreamof said orifice with the axis of each disposed substantially tangentially of said nozzle and in similar directions in proceeding around said nozzle for discharging minor portions of the fuel into said annular space and circumferentially therein, said member having circumferentially spaced openings therethrough in the vicinity of the downstream end of the nozzle member, and said annular member projecting downstream of the nozzle and having an outwardly flared inner surface.

4. A burner assembly for gaseous fuel comprising, a nozzle having a cylindrical wall and a discharge orifice in the downstream end thereof of smaller diameter than the interior of said cylindrical wall, an annular member embracing the downstream end of said nozzle providing an annular space between the exterior of the nozzle and the interior of said annular member, means closing the upstream end of said annular space, said cylindrical wall having a plurality of weep ports therethrough with the axis of each disposed in a substantially chord position with respect to said cylindrical Wall with all of said weep ports sloping in a similar direction in proceeding around the nozzle, means for supplying a gaseous fuel into said nozzle for escape through said discharge orifice with portions of the fuel escaping through said weep ports, said annular member having circumferentially spaced air inlet openings in the vicinity of the downstream end of said nozzle, and the axes of said air inlet opening being disposed substantially radially of said nozzle.

References Cited in the file of this patent Germany Nov. 6, 1939