CROSS-REFERENCES

[0001] The present application claims the benefit of U.S. provisional application no. 61/330,668, filed May 3, 2010, the entirety of which is incorporated herein by reference.

TECHNICAL FIELD

[0002] The present invention relates to gas fired cooking ranges and, more particularly, to burner assemblies used in such ranges.

BACKGROUND

[0003] Gas fired cooking ranges have achieved wide acceptance in both residential and commercial kitchens. A known design for gas fired cook tops in ranges includes separate burner assemblies for each cooking location, with each burner assembly including a venturi and a burner head having gas-emitting orifices.

[0004] Factors such as flame intensity and efficiency, burner assembly cleanability and fuel consumption efficiency are important to both residential and commercial installations. The time required for completing a food course, including initial preparation time for heating and actual cooking time, can be reduced by efficient burner performance and heat transfer to the cooking vessel atop the burner.

[0005] What is needed in the art are burner assemblies that are reliable, use fuel efficiently and heat vessels.

SUMMARY

[0006] In one aspect, a cooking range burner arrangement includes an annular burner head with a plurality of gas orifices. The burner head includes a centrally disposed opening defining a first flow path for flowing secondary air upward into a combustion space proximate the burner head. A bowl arrangement associated with the burner head defines a second flow path and a third flow path. The second flow path is located for flowing secondary air to the combustion space above the secondary flow provided by the first flow path. The third flow path is located for flowing secondary air into the combustion space above the secondary flow provided by the second flow path.

[0007] In the foregoing aspect, the second flow path may be radially outward of the first flow path, and the third flow path radially outward of the second flow path.

[0008] In either foregoing aspect, the second flow path may feed secondary air to a cone and/or mantle flame region and the third flow path may feed secondary air to a tail flame region.

[0009] In any of the foregoing aspects, the bowl arrangement may include an inner bowl structure disposed to define the first air flow path between an upper portion of the burner head and a lower portion of the inner bowl structure, and an outer bowl structure disposed at least partially about the inner bowl structure to define the second air flow path at least partially between the inner bowl structure and the outer bowl structure.

[0010] In any of the foregoing aspects, a inner bowl structure may have a bottom edge aligned with and positioned above a top surface of the burner head, a wall of the inner bowl structure extending upwardly and radially outwardly, and an outer bowl structure may have a bottom edge positioned higher than the bottom edge of the inner bowl structure and lower than a top edge of the inner bowl structure, a wall of the outer bowl structure extending upwardly and outwardly, and a top edge of the outer bowl structure positioned higher than the top edge of the inner bowl structure.

[0011] In any of the foregoing aspects, a first bowl structure and second bowl structure may act as heat reflectors to reduce radially outward heat loss.

[0012] In any of the foregoing aspects, a plate may be positioned above a second bowl structure for being heated by combustion in the combustion space, the plate including a plurality of heat exchange fin structures extending downward toward the combustion space.

[0013] In the immediately foregoing aspect, a multiplicity of the heat exchange fin structures may be arranged to extend radially relative to a central vertical axis of the burner head.

[0014] In the immediately foregoing aspect, radially inward edges of the multiplicity of heat exchange fin structures may be spaced outward of the central vertical axis, a center region of the bottom side of the plate lacking any heat exchange fin structure.

[0015] In the immediately foregoing aspect, the multiplicity of heat exchange fin structures may include a first set of heat exchange fin structures with radially inward edges terminating a first distance from the central vertical axis and a second set of heat exchange fin structures with radially inward edges terminating a second distance from the central vertical axis, the second distance greater than the first distance.

[0016] In the immediately foregoing aspect, a radial length of each heat exchange fin structure of the second set of heat exchange fin structures may be substantially less than a radial length of each heat exchange fin of the first set of heat exchange fin structures.

[0017] In any of the foregoing aspects, an inner bowl structure may have a bottom edge aligned with and positioned above a top surface of the burner head, a wall of the inner bowl structure extending upwardly and radially outwardly; an outer bowl structure may have a bottom edge positioned higher than the bottom edge of the inner bowl structure and lower than a top edge of the inner bowl structure, a wall of the outer bowl structure extending upwardly and outwardly; and a top edge of the outer bowl structure may be positioned higher than the top edge of the inner bowl structure, the top edge of the outer bowl structure positioned adjacent lower edges of heat exchange fin structures.

[0018] In another aspect, a cooking range burner arrangement includes an annular burner head with a plurality of gas orifices, the burner head including a centrally disposed opening defining a first flow path for flowing secondary air upward into a combustion space proximate the burner head. A secondary air flow metering arrangement is associated with the burner head, the secondary air flow metering arrangement defining a second flow path and a third flow path, the second flow path located for flowing secondary air to the combustion space above the secondary flow provided by the first flow path, the third flow path located for flowing secondary air to the combustion space above the secondary flow provided by the second flow path.

[0019] In yet another aspect, a kit for modifying an open-top gas burner including a burner head includes an inner bowl structure for positioning above the burner head, an outer bowl structure disposed at least partially about the inner bowl structure to define an air flow path at least partially between the inner bowl structure and the outer bowl structure; and a plate member for positioning above the inner and outer bowl structure.

BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Fig. 1 is a perspective view of one embodiment of a gas cooking range;

[0021] Fig. 2 is a perspective view of one embodiment of a dual burner head unit;

[0022] Fig. 3 is a perspective view of a plate for a burner arrangement;

[0023] Fig. 4 is a bottom view of the plate of Fig. 3;

[0024] Fig. 5 is a perspective view of an outer bowl structure;

[0025] Fig. 6 is a perspective view of an inner bowl structure;

[0026] Fig. 7 is a cross-section showing the plate of Fig. 3 and bowls of Figs. 5 and 6 in relation to a burner head; [0027] Fig. 8 is a perspective view of another plate;

[0028] Fig. 9 is a bottom view of the plate of Fig. 8;

[0029] Fig. 10 is a perspective view of a support unit; and

[0030] Fig. 1 1 is a cross-section showing the plate of Fig. 8, bowls of Figs. 5 and 6 and support unit of Fig. 10 in relation to a burner head.

DETAILED DESCRIPTION

[0031] Referring to Fig. 1, numeral 10 designates a gas cooking range having a cooktop 14 with multiple cooking locations 1 1 (e.g., six in the illustrated embodiment, 3 front and 3 back) with associated burner heads. In one embodiment, pairs of burner heads are formed by burner head assemblies 12 (per Fig. 2), but each burner head could be formed and fed with gas on an individual basis. Range 10 further includes an oven 16. The range may be a commercial range or a residential range, taking on a variety of outward configurations, of which Fig. 1 is merely exemplary.

[0032] Range 10 includes a gas circuit for supplying combustible gas to each burner head and to an oven burner assembly (not shown). The gas circuit includes a plurality of flow control valves 18 provided for initiating, terminating and controlling the rate of gas flow to cooking locations 1 1 on cook top 14. Range 10 is supported on casters 20, by which range 10 can be moved a short distance to clean the area around the range. However, embodiments without casters are contemplated.

[0033] Exemplary burner head assembly 12 includes a first burner head 22 and a second burner head 24 at which combustion of gaseous fuel occurs. A single piece, monolithic casting 30 forms a first venturi 32 associated with a first burner head base 34 and a second venturi 36 associated with a second burner head base 38. First venturi 32 and second venturi 36 provide a flow of gas and primary combustion air for combustion at first and second burner heads 22, 24, respectively, in front and back locations, respectively, on cook top 14. First and second gas receivers 40, 42 are provided on first venturi 32 and second venturi 36, respectively. Each receiver 40, 42 is aligned with a different control valve 18 to receive gas therefrom when the control valve 18 is opened to allow gas to flow therethrough. Receivers 40, 42 also admit a flow of ambient air to mix with the combustible gas in first venturi 32 and second venturi 36 to provide a combustible mixture to burner heads 22, 24.

[0034] Fig. 2 illustrates burner head assembly 12 in a partial state of disassembly.

Each burner head base 34, 38 may be a substantially annular body defining an open top annular channel 44 between an inner wall 46 and an outer wall 48. Annular channel 44 of burner head base 34 is visible in Fig. 2. A burner head cover 50 is provided on each burner head base 34, 38, with cover 50 on burner head base 38 being shown in Fig. 2. Each cover 50 has a plurality of gas-emitting orifices 52 therein through which a mixture of combustible gas and primary combustion air is emitted.

[0035] Burner head cover 50 fits on burner head base 38 and is a multi-surfaced, generally annular structure. Burner head 50 includes a primarily upwardly facing surface 54, which is a top surface of cover 50. Surfaces radially outward of upwardly facing surface 54 are generally outwardly facing, and include an upwardly and outwardly facing surface 56 adjacent upwardly facing surface 54 and a mostly outwardly facing surface 58, which is the outermost surface of cover 50. Radially inwardly from top surface 54 in cover 50 are multiple surfaces that are generally inwardly facing. An innermost, mostly inwardly facing surface 60 is provided adjacent an inward edge 62 of cover 50. An intermediate surface 64 adjoins innermost surface 60 with top surface 54. Intermediate surface 64 is inwardly and upwardly facing. The number and arrangement of the cover surfaces could vary. Orifices 52 are shown in various of the cover surfaces, with the illustrated orifices being exemplary only. The exact location, size and number or orifices may vary, including providing orifices in surfaces 56 or 58 if desired. The central region of each burner head is open, with a restrictor plate 70 positioned therein for metering secondary air flow to the combustion space via central opening 72 of the plate and an outer gap 74 formed between the plate and the burner head. The restrictor plate may also hold an igniter (e.g., via a slot 76).

[0036] Referring now to Figs. 3-7, one embodiment of a burner head arrangement is described. Figs. 3 and 4 show perspective and bottom plan views respectively of a plate structure 100 having a top surface 102 and a bottom surface 104. The bottom surface includes a plurality of heat exchange fins 106 extending downwardly therefrom. The fins extend radially relative to a center 108 of the plate and terminate at positions away from the center, such that a center region of the bottom side of the plate lacks any heat exchange fin structure. The heat exchange fins include a set of heat exchange fins 106A with radially inward edges terminating a radial distance Rl from the center of the plate and a set of heat exchange fins 106B with radially inward edges terminating a large radial distance R2 from the center of the plate. The fins 106A and 106B are arranged in an alternating manner about the plate center. In the illustrated embodiment, a radial length of each heat exchange fin 106B is substantially less than a radial length of each heat exchange fin 106A (e.g., fins 106B have a radial length that is 60% or less the radial length of fins 106A). However, variations are possible. Certain of fins 106A extend further outward of the plate and include downwardly extend portions to define feet 1 10 that can support the plate. The plate may be made of stainless steel, hot rolled steel, cast iron or other materials. In some embodiments all or portions (e.g., the bottom surface and/or fins) of the plate may be coated to further improve heat transfer to the plate structure (e.g., coated with copper via a plasma spray process). Laminate plate structures could also be used.

[0037] Figs. 5 and 6 depict components of a secondary air metering arrangement.

In the illustrated embodiment an inner bow structure 120 and outer bowl structure 122 are provided. The term "bowl" is used in connection with the structures as they each have a respective top edge 124, 126 that is spaced outward of the bottom edge 128, 130 in the manner of a typical bowl. However, the bowl structures are open at the bottom for purpose of their use in the secondary air flow metering as will be described below.

[0038] Referring now to Fig. 7, a burner head arrangement cross-section is provided. The range housing 140 supports a range aeration pan unit 142. A burner head 24 with associated restrictor plate is provided to define a center opening 72 and an annular opening 74. The bowl structures 124 and 126 are positioned for metering air flow to the combustion spaced, which is generally shown by dashed line area 144. As shown, the inner bowl structure 120 has its bottom edge 128 aligned with and positioned above the top surface of the burner head 24, and the wall of the inner bowl structure extends upwardly and radially outwardly. The outer bowl structure 122 has its bottom edge 130 positioned higher than the bottom edge 128 of the inner bowl structure 120 and lower than the top edge 124 of the inner bowl structure. The wall of the outer bowl structure extends upwardly and radially outwardly. The top edge 126 of the outer bowl structure 122 is positioned higher than the top edge 124 of the inner bowl structure 120. The top edge of the outer bowl structure is positioned proximate (e.g., immediately adjacent or in contact with) the bottom edge of the fin structures.

[0039] The inner bowl structure may be supported by radially extending feet that engage the burner head, and the outer bowl structure may be supported on the inner bowl structure (e.g., via radially outward extending structure on the inner bowl and

corresponding radially inward extending structure on the outer bowl). In another implementation the pan unit 142 may include structure that supports the inner bowl, and the outer bowl may be supported by either the inner bowl or the pan unit 142.

[0040] Secondary air is delivered to the combustion space 144 via flow paths 150 and 152 upward through the center of the burner head 24. Secondary air is also delivered to the combustion space 144 via a flow path 154 between the bottom edge 128 of the inner bowl and the upper surface of the burner head. Secondary air is further delivered to the combustion space 144 via a flow path 156 between the inner and outer bowl.

Notably, flow path 154 is radially outward of the flow paths 150 and 152, and flow path 156 is radially outward of the flow path 154.

[0041] An alternative embodiment is shown in Figs. 8- 1 1, where a plate structure

170 includes radially extending heat exchange fins 172A, 172B on its bottom surface, but no feet for supporting the plate. Instead, certain fins 172A including a support extension 174 that is configured and sized to rest atop a ring structure 176 of a support unit 178, which may be of wire rod construction and may or may not be plated (e.g., nickel plated). Multiple clip structures 180 may be engaged with the support unit 178 to support both the outer bowl 122 and the inner bowl 120. Similar secondary air flow paths 150, 152, 154 and 156 to the combustion space 144 are provided. A vertical central axis 190 of the burner head and overall arrangement is also shown.

[0042] In the illustrated embodiments, the controlled metering of secondary air to the combustion space via the defined flow paths helps to improve combustion efficiency (increasing resultant C02 in the flue gas produced through the reduction of excess secondary air throughout the combustion process). Notably, the flow path 154 feeds secondary air to a cone and/or mantle flame region of the combustion space. The flow path 156 feeds secondary air to a tail flame region of the combustion space to help complete combustion. The bowls act to direct heat by reflection and metering in the secondary air to help limit outward movement of the flame. The bowls also provide a shielding and insulating effect that maintains heat beneath the plate, reducing jacket losses. For example, the secondary flow through path 156 acts somewhat like an insulating blanket flow of air. The bowls also help protect the combustion space 144 from being subject to external environmental issues such as air movement around the range (e.g., via make-up air, fans used in the vicinity of the range air movement caused by persons moving in the vicinity of the range). Additionally, the combination of the plate and bowls helps prevent any boilover from reaching the burner head. [0043] The plate is designed to collect heat from burner flame and normally exhausted gases and renders the energy to the cooking utensil that may be positioned atop the plate. The collected and transferred energy is greater than the sum of open flame contact and plate to utensil contact losses, therefore yielding thermal efficiency gains.

[0044] In one implementation of a burner head configuration designed to operate at an input rate of about 30,000 BTUs, the gap between the burner head and bottom edge of the inner bowl may, for example, be on the order of 1/12 to 1/2 inch and the radial distance between the inner bowl and outer bowl may be on the order of 1/4 to 3/4 inch. However, variations on these dimension are possible depending upon a variety of factors such as burner head size, number and locations of orifices, input rate etc. Flue gas analysis (e.g., measurement of CO and CO ₂ ) may be used to determine desirable dimensions in any given instance.

[0045] The subject secondary air metering arrangement may be provided as a kit for modifying or updating a standard gas burner arrangement in which a removable grate is positioned above the burner head. The grate is simply removed and replaced with the assembly (e.g., the support structure 178, plate 170 and bowls 120 and 122).

[0046] It is to be clearly understood that the above description is intended by way of illustration and example only and is not intended to be taken by way of limitation. For example, the inner and outer bowl 120 and 122 could be formed as a combined structure (e.g., with the outer bowl including a number of inwardly extending fingers to which the inner bowl is tack-welded). In another example, the bowls and plate may all be connected together in a permanent manner. Moreover, other structures could be produced to define desired secondary air flow metering into the combustion space. Other changes and modifications could be made.

[0047] What is claimed is: