Burner nozzle

Details Burner nozzle Burner nozzle

1999-02-24

2001-02-20

Lazarus, Ira S. (Department: 3743)

Combustion

Mixer and flame holder

C431S353000, C431S286000, C239S556000

Reexamination Certificate

active

06190163

ABSTRACT:

FIELD OF INVENTION
This invention relates to burners and, more specifically, to gas burners suitable for use in appliances and the like.
BACKGROUND OF THE INVENTION
Burners are used, for example, in apparatuses including furnaces and appliances such as clothes dryers. A principle component of burners is a nozzle typically in the form of a venturi tube. Combustible gas is fed into the nozzle and entrains air into the nozzle. The air and gas is mixed in the venturi and the mixture emerges from the outlet end. An igniter may be attached directly to the venturi tube in front of the outlet opening in alignment with a longitudinal axis along which the nozzle extends and ignites the mixture as it leaves the outlet, thereby creating flame which produces heat that is utilized by the apparatus.
In furnaces, a plurality of burner nozzles are typically arranged side-by-side and are designed for cross-ignition of the gas in adjacent nozzles. One conventional nozzle has two plenum chambers located at an outlet end of the venturi tube. Each plenum chamber has a thin outlet slit along its side edges. Flame released from the side outlet slits of one nozzle ignites gas from an adjacent nozzle.
Clothes dryer burners may be horizontally fired into ducts of the dryer. The ducts shield the open flame and force the heated gases in the desired direction. The burner may include an attachment known as a flame spreader which is separately formed from the nozzle, mounted such as by welding to the nozzle and axially spaced from the outlet opening of the nozzle. Flame spreaders shorten and spread out the flame transverse to a direction of gas flow. The flame spreaders are disposed in the flame and thus, are exposed to relatively high temperatures. This requires the flame spreaders to be fabricated from metals which can withstand this high temperature environment.
Conventional gas dryer burner nozzles typically produce flame having a length of, for example, about one foot. However, space is limited in the dryer. Long flame lengths may result in inefficient heat transfer between the flame and air inside the ductwork, overheating of the ductwork, or an increase in the cost of the dryer due to the use of enough ductwork and other components to accommodate the long flame. Heated gases from the horizontal flame are typically directed through a 90° elbow, generally vertically to another 90° elbow, through a screen and then into a rotatable drum in which clothes are dried. An air blower may be disposed upstream or downstream of the burner for directing air in the drum of the dryer.
Typical gas dryer burner nozzles can be difficult and relatively expensive to manufacture. Generally, such burner nozzles are fabricated by a practice of shaping the body from tubing and attaching flame spreaders and brackets by welding. Another problem with conventional dryer burner applications is that they are susceptible to igniter breakage. More specifically, the igniters are connected directly to the burner nozzle and, being fragile, may crack or break off during shipping and handling.
SUMMARY OF THE INVENTION
The present invention is directed to a burner nozzle for producing shaped and/or shortened flame for efficient heat transfer. The burner is characterized by flame-shaping openings for shaping the flame. Alternatively, or in combination with the flame-shaping openings, the burner nozzle may include a flame length reducing member. The burner is particularly well suited for use in clothes dryers where flame that is elongated transverse to the direction of gas flow and has a reduced length, reduces fabrication costs and results in efficient heat transfer.
In general, a first embodiment of the invention is a burner nozzle that includes a burner tube that extends along a central axis and has an inlet end portion for receiving combustible gas and air and an outlet opening for releasing a mixture of the gas and air. A main gas flow passage extends along the central axis between the inlet end portion and the outlet opening. At least one chamber has at least a portion disposed alongside and in communication with the main gas flow passage along the central axis. At least one flame-shaping opening is located adjacent the end face. Each chamber extends along the central axis to an associated flame-shaping opening. Each flame-shaping opening is constructed and arranged effective to elongate flame resulting from combustion of the mixture transverse to the central axis to produce efficient heat transfer between the flame and air inside a heat-receiving member such as a duct, located downstream of the outlet opening.
As to the specific features of the burner nozzle of the first embodiment, the outlet opening may be disposed along a plane of an end face of the burner tube. Each elongated flame-shaping opening may be located only in or generally parallel to the plane of the end face such that the mixture only leaves the burner tube through each flame-shaping opening and the outlet opening. Each chamber may extend along the central axis to an associated flame-shaping opening and has a generally uniform height along its entire length. A device for igniting the mixture may be fastened to the combustion tube and positioned offset from the outlet opening and aligned with a flame-shaping opening. The outlet opening is generally circular and two flame-shaping openings may have a rectangular shape and be located around the outlet opening diametrically opposed from each other.
In general, a second embodiment of the invention is directed to a burner nozzle comprising a burner tube that extends along a central axis and has an inlet end for receiving a combustible mixture of gas and air. A body has a passageway in communication with the burner tube and has an elongated outlet end portion. At least one flame shaping opening is disposed near the outlet end portion for releasing a mixture of the gas and air. A baffle formed integrally with the body may project outwardly near the outlet end portion for obstructing air flowing externally of the burner nozzle.
More specific features include at least one tab portion that extends at an angle with respect to the central axis to obstruct at least a portion of the flame-shaping opening. Each tab portion has a first section that extends from the body at an angle with respect to the central axis and a second section that extends from the first section substantially perpendicular to the central axis. Also included are a first set of the tab portions and a second set of the tab portions that face each other. The tab portions in the first and second sets extend from the body in an alternating “zipper like” arrangement relative to each other. Alternatively, an end face may be disposed near the outlet end portion and have at least one angled or curved surface relative to the central axis, a plurality of the flame shaping openings being disposed in the surface. At least one recess may project inwardly from the body and restricts the passageway for directing flow of the gas and air in the body.
A preferred aspect of the burner nozzle comprises a burner tube that extends along the central axis and has an inlet end for receiving a combustible mixture of gas and air.
The body has a passageway in communication with the burner tube and an elongated outlet end portion. The end face is disposed near the outlet end portion and has at least one angled or curved surface. A plurality of flame shaping openings are disposed in the surface for releasing a mixture of the gas and air.
Another preferred aspect of the burner nozzle comprises a burner tube that extends along the central axis and has an inlet end for receiving a combustible mixture of gas and air. The body has a passageway in communication with the burner tube and an elongated outlet end portion. At least one flame shaping opening is disposed near the end portion for releasing a mixture of the gas and air. At least one tab portion extends at an angle with respect to the central axis so as to obstruct at least a portion of the at least one flame shaping opening. The tab portion

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