Burner flame stability chamber

Abstract

A burner body is disclosed for use in a gas burner assembly. The burner body includes a sidewall and a main gas conduit, the main gas conduit having an inlet and an outlet; a plurality of primary burner ports disposed within the sidewall so as to be in communication with the outlet of the main gas conduit; a simmer flame port disposed within the sidewall in a spaced relation with the primary burner ports for providing a reignition source therefore; and a stability chamber disposed within the burner body, wherein the stability chamber comprises at least a first expansion region and a second expansion region, wherein the second expansion region has a greater volume than the first expansion region.

Description

BACKGROUND OF THE INVENTION[0001]The subject matter disclosed herein relates to gas appliances, such as gas ranges, and more particularly, to stability chambers for use in such gas appliances.[0002]Atmospheric gas burners are often used as surface units in household gas cooking appliances. A significant factor in the performance of gas burners is their ability to withstand airflow disturbances in the surroundings, such as room drafts, rapid movement of cabinet doors, and rapid oven door manipulation. Manipulation of the oven door is particularly troublesome because rapid openings and closings of the oven door often produce respective under-pressure and over-pressure conditions within the oven cavity. Since the flue, through which combustion products are removed from the oven, is sized to maintain the desired oven temperature and is generally inadequate to supply a sufficient air flow for re-equilibration, a large amount of air passes through or around the gas burners. In particular,...

AI Technical Summary

Benefits of technology

The patent improves the ability of a stability chamber to re-light flames of adjacent flame ports using low flow rates without affecting performance at high flow rates.

Problems solved by technology

Manipulation of the oven door is particularly troublesome because rapid openings and closings of the oven door often produce respective under-pressure and over-pressure conditions within the oven cavity.

Since the flue, through which combustion products are removed from the oven, is sized to maintain the desired oven temperature and is generally inadequate to supply a sufficient air flow for re-equilibration, a large amount of air passes through or around the gas burners.

In particular, pressure fluctuations from, for example, cabinet or door openings, cause the structures to expand or contract (e.g., the sheet metal deflects) and this structural movement pumps air into adjacent cavities, causing the temporary under or over pressure conditions.

This surge of air around the gas burners, due to over pressure or under pressure conditions in the oven cavity, is detrimental to the flame stability of the burners and extinguish the flames.

This flame stability problem is particularly evident in sealed gas burner arrangements, referring to the lack of an opening in the cooktop surface around the base of the burner to prevent spills from entering the area beneath the cooktop.

Flame instability is caused by the low pressure drop of the fuel / air mixture passing through the burner ports of a typical rangetop burner.

A low pressure drop across the ports allows pressure disturbances propagating through the ambient to easily pass through the ports, momentarily drawing the flame towards the burner head and leading to thermal quenching and extinction.

An additional problem is that rapid adjustments of the fuel supply to a gas burner from a high burner input rate to a low burner input rate often will cause flame extinction when the momentum of the entrained air flow continues into the burner even though fuel has been cut back, resulting in a momentary drop in the fuel / air ratio, causing extinction.

When a negative pressure disturbance enters the burner (suction, for example, from the opening of an oven door), the pressure drop and flow velocity through the main burner ports are momentarily reduced causing unwanted extinction of the main burner flames.

Although such gas burners having an expansion chamber provide somewhat improved stability performance at simmer settings, disturbances continue to cause unwanted extinction.

Furthermore, these expansion chambers have excessively large flames at higher burner input rates.

The flame from the stability chamber port, however, is dissimilar to the flames from the other ports and gives the burner a non-symmetric flame appearance.

In addition, stability chambers have an inherently lazy plume of gas exiting the chamber during operation, due to the slow velocity of the fuel mixture exiting the chamber.

The slow velocity of the fuel mixture reduces the kinetic energy of the flame and hence the ability to entrain secondary air.

This, in turn, causes this plume of flame to reach longer for more air and impinge on cool surrounding surfaces such as the cookware above the burner.

However, when this is done, it becomes more difficult for the chamber's flame to reignite the adjacent ports after an unwanted flame extinction due to the larger distance between flames.

Images