GAS BURNER

Abstract

A gas range has a cook top and a gas burner assembly. The gas burner assembly includes a burner body positioned in the cook top and connected to a source of gas. The burner body has at least one substantially enclosed chamber. The chamber has an inner wall with at least one port, and an outer wall with at least one port. At least one gas conduit with a substantially round entry for receiving a gas flow, a throated region, and a non-round exit in flow communication with the at least one chamber.

Description

BACKGROUND OF THE INVENTION

This invention relates generally to an apparatus for gas burners, and, more particularly, an apparatus for improved flow characteristics for gas surface burners used in a gas-cooking product.

Atmospheric gas burners are commonly 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 from the surroundings, such as room drafts, rapid movement of cabinet doors, and 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 under the cook top.

These under-pressure and over-pressure conditions cause related pressure variations in the gas entering the burner chamber. Gas refers to any gas or fuel air mixture. The pressure variations can translate into flow disturbances at the burner ports causing flame extinction.

Gas surface burners used in cooking products typically include a burner body including a plurality of burner ports through which a gas is distributed, and a burner cap positioned over the burner body. Almost all designs include an internal chamber of increased gas volume near the burner ports. This is important where gas flow may change over time. Providing equal flame characteristics from one port to the next is critical to prevent hot spots or uneven heating of the cooking vessels. Variations in the size of the burner port and the distance of the burner port from the venturi can also affect the flame characteristics. Adverse changes in the flame characteristics are detrimental to various performance characteristics such as the inability to support flames at certain ports particularly at very low input rates.

In these burners there are a number of port rings for the combustion of the gas. A typical multi-ring burner would include a doughnut shaped outer burner and a single inner burner. The outer burner would have a ring of ports on the outside and inside of the burner. This would create a triple ring burner. However, these burners, while uniform in applying heat the cooking vessel, are only efficient for large cooking vessels where the diameter of the vessel is larger than the burner. This is because there are several main factors influencing the minimum size of a triple ring burner. First, the inner burner must be sized to accommodate a stability chamber as discussed above. Second, the outer burner must be offset from the inner burner, further, the width of the outer ring is determined by the size of the venturi supplying gas to the chambers of the outer burner. Thus the minimum diameter of the outer ring=diameter of the inner burner+2×offset from inner burner to outer burner+2×width of the outer burner. Thus, as there is a finite distance to be maintained between the inner and outer burners and a finite size is required for the inner burner, there is a need to reduce the width of the outer burner to decrease the size of the burner assembly.

SUMMARY OF THE INVENTION

As described herein, embodiments of the invention overcome one or more of the above or other disadvantages known in the art.

In one aspect, a gas range has a cook top and a gas burner assembly. The gas burner assembly includes a burner body positioned in the cook top and connected to a source of gas. The burner body has at least one substantially enclosed chamber. The chamber has an inner wall with at least one port, and an outer wall with at least one port. At least one gas conduit with a substantially round entry for receiving a gas flow, a throated region, and a non-round exit in flow communication with the at least one chamber.

In another aspect, a gas burner assembly is connected to a source of gas. The gas burner assembly has a burner body. The burner body comprises at least one substantially enclosed chamber. The chamber has an inner wall with at least one port, and an outer wall with at least one port. At least one venturi has an input for receiving a gas flow, a throated region, and a non-round exit in flow communication with the at least one chamber.

In yet another aspect, a gas range has a cook top; and a gas burner assembly. The gas burner assembly includes a burner body positioned in the cook top and connected to a source of gas. The burner body comprises at least one chamber and at least one venturi. The chamber has an inner wall with at least one port, and an outer wall with at least one port. The at least one venturi has an input for receiving a variable gas flow, a throated region and an elliptical exit in flow communication with the at least one chamber.

BRIEF DESCRIPTION OF THE DRAWINGS

The following figures illustrate examples of embodiments of the invention. The figures are described in detail below.

FIG. 1 is a perspective view of a gas range according to an embodiment of the invention.

FIG. 2 is a perspective view of a burner assembly of the range of FIG. 1 according to an embodiment of the invention.

FIG. 3 is a perspective view of a burner body of the burner assembly of FIG. 2 according to an embodiment of the invention.

FIG. 4 is a top view of a burner body of the burner assembly of FIG. 2 according to an embodiment of the invention.

FIG. 5 is a cutaway view of the burner body of FIG. 3 along centerline 5-5.

FIG. 6 is a perspective view of multi-ring burner assembly incorporating a burner assembly of FIG. 2.

DETAILED DESCRIPTION OF THE INVENTION

While the methods and apparatus are herein described in the context of a gas-fired cook top, as set forth more fully below, it is contemplated that the herein described method and apparatus may find utility in other applications, including, but not limited to, gas heater devices, gas ovens, gas kilns, gas-fired meat smoker devices, and gas barbecues. In addition, the principles and teachings set forth herein may find equal applicability to combustion burners for a variety of combustible fuels. The description herein below is therefore set forth only by way of illustration rather than limitation, and is not intended to limit the practice of the herein described methods and apparatus.

Typically, for a burner chamber, flow distribution is governed by individual port areas. The larger ports exhibit higher flow rates than smaller ports. Thus, port sizing, a static attribute of a burner, primarily determines this flow characteristic. This defines the distribution of flow rates across the burner ports. In some cases, it is desired that the flow characteristics be “dynamic” or variable. One such instance would be in a burner where an interior region of ports are altered during high flow and unaltered during low flow conditions. For example, the inside ports are optimized for a particular flow and therefore produce poor and undesirable operational conditions when a flow other than the optimized flow conditions are experienced. Particularly, the ports require a minimum flow rate to prevent premature extinguishing of the cooking flame, however, due to oxygen requirements for proper burning, also exhibit poor performance during high flow conditions.

FIG. 1 illustrates an exemplary freestanding gas range 100 in which the herein described methods and apparatus may be practiced. Range 100 includes an outer body or cabinet 112 that incorporates a generally rectangular cook top 114. An oven, not shown in detail, is positioned below cook top 114 and has a front-opening access door 116. A range backsplash 118 extends upward of a rear edge 120 of cook top 114 and contains various control selectors (not shown) for selecting operative features of heating elements for cook top 114 and the oven. It is contemplated that the herein described apparatus is applicable, not only to cook tops which form the upper portion of a range, such as range 100, but to other forms of cook tops as well, such as, but not limited to, built in cook tops that are mounted to a kitchen counter. Therefore, gas range 100 is provided by way of illustration rather than limitation, and accordingly there is no intention to limit application of the herein described methods and apparatus to any particular appliance or cook top, such as range 100 or cook top 114.

Cook top 114 includes four gas fueled burner assemblies 200 which are positioned in spaced apart pairs positioned adjacent each side of cook top 114. Each pair of burner assemblies 200 is surrounded by a recessed area 124 of cook top 114. Recessed areas 124 are positioned below an upper surface 126 of cook top 114 and serve to catch any spills from cooking utensils (not shown in FIG. 1) being used with cook top 114. Each burner assembly 200 extends upwardly through an opening in recessed areas 124, and a grate 128 is positioned over each burner 200. Each grate 128 is adapted to provide the desired support of cooking vessels and utensils over burner assemblies 200 for cooking of meal preparations placed therein.

FIG. 2 is a perspective view of an exemplary burner assembly 200 that can be used with gas range 100 (shown in FIG. 1). Burner assembly 200 includes a burner cap 202 and a burner body 206. A main gas conduit 208 has an orifice 212 and is open to an interior chamber or chambers of burner body 206 and defines a passage which extends axially through the base of burner body 206 to provide a gas or a fuel/air mixture to flow into burner assembly 200. As used herein, the term “gas” refers to a combustible gas or gaseous fuel-air mixture.

Burner assembly 200 is mounted on a support surface, such as cook top 114, of a gas-cooking appliance such as a range or a cook top 100 (see FIG. 1). A cap 202 is disposed over the top of burner body 206. Gas enters burner body 206 at orifice 212 and traverses gas conduit 208 before entering the chambers of burner body 206. Burner assembly 200 also includes at least one igniter (not shown) extending through an opening in burner body 206. While one type of burner is described and illustrated, the herein described methods and apparatus are applicable to other types of burners, such as stamped aluminum burners and separately mounted orifice burners.

Referring to FIG. 6 a multi-ring burner assembly is shown. The multi-ring burner assembly has an inner burner assembly 300 and an outer burner assembly 200. Inner burner assembly has a single ring of ports and burner cap 302. Outer burner assembly 200 has two rings of ports. One ring of ports faces to the outside, the second ring of ports (hidden by cap 202) faces to the inside, or toward the inner burner assembly 300. Gas conduit 208 provide a supply of gas to the outer burner body 206.

Now referring to FIGS. 3 and 4, FIG. 3 is a perspective view of a burner body 206. FIG. 4 is a top view of burner body 206 that can be used with gas range 100 (shown in FIG. 1). Burner body 206 includes at least one conduit orifice 212 where a gas is introduced. For each orifice 212 the gas travels up gas conduit 208 to an opening 210. Each opening 210 is in flow communication with at least one chamber or set of chambers 220, 240 and 260. Chambers 240 and 260 are on opposite sides of opening 210 and will be described as separate chambers even though the chambers are not separated by a physical obstruction and each chamber experiences similar pressure and flow of gas from opening 210.

Gas is supplied to ports 222 via chamber 220. Gas is supplied to ports 262 and 264 via chamber 260. Gas is supplied to ports 242 via chamber 240. Annular chamber 220 is defined by an outer wall 221, an inner wall 223, a lower surface of the burner body 206, and cap 202. A plurality of primary burner ports 222 are disposed in outer wall 221. Primary burner ports 222 are typically, although not necessarily, evenly spaced about outer wall 221. Inner wall 223 forms an isolation wall between chamber 220 and chamber 240. Chamber 240 is further defined by a wall 241. A plurality of burner ports 242 are disposed in wall 241. As used herein, the term “port” refers to an aperture of any shape from which a flame may be supported.

FIG. 5 is a cutaway view of FIG. 3. A gas conduit 208 typically has a round orifice 212 where gas enters. A single jet 290 is used for directing a fuel into orifice 212. The jet 290 is configured smaller then orifice 212 so atmospheric may enter between the jet 290 and the wall 213 around orifice 212. The velocity of the fuel exiting the jet 290 at orifice 302 draws atmospheric air into gas conduit 208. The fuel and atmospheric air compress and mix while traveling through a necked region 211 of the gas conduit 208. The necked region has a maximum cross section at the orifice 212 and a minimum cross-section where transition region 209 begins. For optimum performance a round cross-sectional orifice 212 is used. However, under some circumstances, a uniformly round opening 210 is not desirable.

A uniformly round opening is not desirable where the distance between the inner ring of ports 242, 262 and outer ring of ports 222 and 264 is less than the necessary diameter of the opening 210. The size of opening 210 is determined by the flow rate of gas during maximum output of the burner. In these conditions it may be necessary for opening 210 to have a diameter greater then the distance between the inner and outer wall.

For example, there are situations where inadequate space is available for an opening 210 to have a symmetrically round cross section. Particularly, a finite distance is needed between the venturi opening 210 and the ports 265 immediately radially adjacent to the opening 210. If ports 265 are too close to opening 210 much higher pressures will be experienced at the ports. The higher pressure reduces flame stability and would create a hot spot under the cooking vessel. The individual size of each of the ports 256, relative to ports further from the opening, may not be reduced either, because the reduced size ports would then not support flames at anything other than maximum gas input rates.

Making the opening 210 non-round allows more space to put a baffle 270 (or wall) between the opening and the ports 265 without increasing the diameter of the burner. As shown in FIGS. 3 and 4 the opening 210 is non-round and has an elliptical shape. However, any non-round shape may be used that is capable of supplying gas at the maximum flow rate. The baffle 270 redirects the flow along the baffle 270, parallel with the ports 265, rather than normally into it. This way, more uniform port loading is achieved without varying the relative size of each of the ports. Further, the elliptical shape of opening 210 reinforces the action of the baffle 270, directing flow in a manner that reduces the need to vary ports sizes to gain uniform flame lengths between individual ports.

The methods and apparatus described herein facilitate providing substantially uniform heat distribution at relatively low input rates in a smaller diameter burner assembly.

While the invention has been described in terms of various specific embodiments, those skilled in the art will recognize that the invention can be practiced with modification within the spirit and scope of the claims.

Claims

1. A gas range comprising: a cook top; and a gas burner assembly comprising a burner body positioned in the cook top and connected to a source of gas, the burner body comprising:

at least one substantially enclosed chamber, the chamber comprising an inner wall having at least one port, and an outer wall having at least one port;

at least one gas conduit comprising a substantially round entry for receiving a gas flow, a throated region, and a non-round exit in flow communication with the at least one chamber.

2. The gas range of claim 1, wherein the length of the exit of the gas conduit is greater then the distance between the inner wall and the outer wall.

3. The gas range of claim 1, wherein the exit of the gas conduit is elliptical.

4. The gas range of claim 1, wherein the burner body further comprises a baffle configured between the exit of the gas conduit and the outer wall.

5. The gas range of claim 1, wherein the burner body comprises three substantially enclosed chambers each chamber comprising an inner wall having at least one port and an outer wall having at least one port.

6. A gas burner assembly connected to a source of gas, the gas burner assembly comprising:

a burner body comprising: at least one substantially enclosed chamber, the chamber comprising an inner wall having at least one port, and an outer wall having at least one port; at least one venturi comprising an input for receiving a gas flow, a throated region, and a non-round exit in flow communication with the at least one chamber.

7. The gas burner assembly of claim 6, wherein the length of the exit of the gas conduit is greater then the distance between the inner wall and the outer wall.

8. The gas burner assembly of claim 6, wherein the exit of the gas conduit is elliptical.

9. The gas burner assembly of claim 6, wherein the burner body further comprises a baffle configured between the exit of the gas conduit and the outer wall.

10. The gas burner assembly of claim 6, wherein the burner body comprises three substantially enclosed chambers each chamber comprising an inner wall having at least one port and an outer wall having at least one port.

11. A gas range comprising: a cook top; and a gas burner assembly comprising a burner body positioned in the cook top and connected to a source of gas, the burner body comprising:

at least one chamber, the chamber comprising an inner wall having at least one port, and an outer wall having at least one port;

at least one venturi comprising: an input for receiving a variable gas flow; a throated region; and an elliptical exit in flow communication with the at least one chamber.

12. The gas range of claim 11, wherein the burner body further comprises a baffle configured between the exit of the gas conduit and the outer wall.

13. The gas range of claim 11, wherein the burner body comprises three substantially enclosed chambers each chamber comprising an inner wall having at least one port and an outer wall having at least one port.