Plural Rate Burner With Flame Enhancement

Abstract

A burner produces an outward extending flame at a high rate and an upward extending flame at a low rate. Facilities are provided for enhancing the entrainment of air in both the outward extending flame and the upward extending flame.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to burners for gaseous fuel and in particular to burners for operating at more than one rate.

2. Description of the Prior Art

There are number of prior art burners, as exemplified by U.S. Pat. No. 3,405,999, which can be operated at more than one rate. Prior art plural rate burners produce acceptable flames when burning natural gas; however, some burners have not provided suitable blue flames when burning propane gas, or the like, due to the higher BTU per cubic foot content of propane gas and the higher proportional air mix requirement.

SUMMARY OF THE INVENTION

The invention is summarized in that a burner for operating at both low and high rates includes a burner member having an inlet for receiving gas and a port for projecting gas in a first direction such that during a high rate of operation a high rate flame extending for at least a predetermined distance along the first direction is produced and during a low rate of operation a low rate flame deviating from the first direction in less than said predetermined distance to a second direction transverse to the first direction is produced, a first spreader spaced in the first direction from the burner member in the path of the high rate flame for enhancing the burning of the gas in the high rate flame, a second spreader spaced in the second direction from the port and having an opening for allowing passage of the low rate flame, and means disposed within the opening for dispersing the low rate flame to enhance the burning of the gas in the low rate flame.

An object of the invention is the construction of a plural rate burner having enhanced flame characteristics at a low rate of operation.

Another object of the invention is to provide a plural rate burner suitable for operation on high-heat-generating-capacity gaseous fuels, such as propane gas.

An advantage of the invention is the elimination of yellow flames when a burner of the non-aerated type is operated at a low rate.

An additional feature of the invention is the provision of a tab with an enlarged head portion extending within an opening for dispersing a low rate flame to enhance the burning of gaseous fuel in the low rate flame.

Other objects, advantages and features of the invention will become apparent from the following description of the preferred embodiment taken in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a elevation view in cross section of a burner apparatus in accordance with the invention and illustrating a low rate of operation.

FIG. 2 is a elevation view with parts broken away illustrating a high rate operation of the burner apparatus shown in FIG. 1.

FIG. 3 is a top view of a lower flame spreader of the burner apparatus shown in FIGS. 1 and 2.

FIG. 4 is a perspective view, partially broken away of the lower flame spreader shown in FIG. 3.

FIG. 5 is a top view of an upper flame spreader of the burner apparatus shown in FIGS. 1 and 2.

FIG. 6 is a perspective view of the upper flame spreader shown in FIG. 5.

DESCRIPTION OF THE PREFERRED EMBODIMENT

As illustrated in FIG. 1, the present invention is embodied in a burner apparatus which includes, an annular burner member indicated generally at 16, a lower flame spreader indicated generally at 13, an upper flame spreader indicated generally at 15, a flame shield 70, a flame-sensing element 42 and a support 32. The burner apparatus is designed to be operated by plural rate gaseous supply facilities (not shown) such as the fuel control device disclosed in U.S. Pat. application Ser. No. 98,246 by Jay R. Katchka and Henry C. Braucksiek filed on Dec. 15, 1970, now U.S. Pat. No. 3,762,639, issued Oct. 2, 1973.

The annular burner member 16 has an outer tubular section 12 and an inner tubular section 14 which form an annular chamber 18. The tubular sections 12 and 14 are coaxial with the upper ends joined and with a lower flanged portion 20 of the inner tubular section joined to the lower end of the outer tubular section 12. A fitting 22 is secured within an opening 24 in the outer tubular section 12 to form an inlet to the chamber 18. A plurality of circumferentially-spaced and outward-facing burner ports 26 are formed in the outer tubular section 12 while a single inward and upward directed burner port 28 is formed in a deformed portion 30 of the inner tubular section 14. The outer tubular section 12 is generally conical so that the annular chamber 18 is gradually reduced in cross section toward the upper end.

The tubular support 32 is suitably secured to a bottom plate 34 attached to the annular burner member 16 and has upper slotted spring portions 36 with dimples 38 mating with a groove 40 in the flame sensing element 42. The element 42 is supported along a vertical axis of the annular burner member 16 and extends above the annular burner member 16 such that upward extending flames from the ports 26 curving inward above the annular member 16 impinge upon the element 42. The flame sensing element is any suitable thermo-responsive device, such as a thermocouple, which can be used to operate safety facilities, such as a magnetic safety valve (not shown), to prevent release of hazardous gas in the event that the flame of the burner is extinguished by air drafts, loss of fuel, etc. Openings 44 are formed in the bottom plate 34 and are sufficiently sized to supply adequate air for mixing with gas from the port 28.

The lower flame spreader 13, shown in FIGS. 3 and 4, has downward bent leg portions 46 extending from an upward flaring frusto-cone portion 48. Tabs 50 are provided on the leg portions 46 and are attached, as illustrated in FIG. 2, to the outer tubular section 12 below the ports 26, so that the frusto-cone portion 48 is in the path of gas flames extending outwardly from the burner ports 26. An opening 52 between the frusto-cone portion 48 and the outer tubular section 12 is sufficiently large to supply adequate air for mixing with gas from the ports 26.

The upper flame spreader 15, shown in FIGS. 5 and 6, has an annular plate-like portion 56 connected by spokes 58 to a collar 60 which is attached to the outer tubular section 12 above the burner ports 26, as illustrated in FIG. 2, so that the plate-like portion 56 is disposed above the path of gas flames extending outward from the ports 26. Openings 62 formed by the spokes 58, the plate-like portion 56 and the collar 60 are circumferentially spaced around and adjacent to the annular burner member 16 for passing upward extending flames, as illustrated in FIG. 1, from the ports 26. Tabs 64 with enlarged head portions 66 extend inward from the annular portion 56 into the openings 62.

The shield 70 is frustro-conically formed and is secured to the upper flame spreader 15 by outward bent tabs 72 extending through the openings 62. A spaced top 74 is bent horizontally from an upward extending leg 76 of the shield 70 and secured in position by inwardly bent tabs 78 from upward extending legs 80 from the shield 70.

The operation of the plural rate burner at a low rate is illustrated in FIG. 1. With a relatively low pressure gaseous fuel supplied to the inlet fitting 22 and chamber 18 of the annular burner member 16, flames sustained by fuel exiting through ports 26 extend upward through the openings 62 in the upper spreader member 15. The tabs 64 and head portions 66, shown in FIGS. 5 and 6, disperse the upward extending flames to enhance the entrainment of air with the burning fuel and to eliminate yellow flames and produce acceptable blue flames. The low rate flames passing through the openings 62 converge inward over the top of the annular burner 16 toward the axis of the annular burner member 16 to impinge upon the flame sensing element 42. The shield 70 protects the low rate flames from being extinguished by a draft of air or other similar disturbance. The spacing of the top 74 from the shield 70 by the legs 76 and 80 provides adequate ventilation for the flame inpinging upon the sensing element 42.

At the high rate of operation illustrated in FIG. 2, the pressure of the fuel within the annular burner member 16 is sufficient to direct flames in a generally horizontal direction outward from the ports 26 against the frusto-conical portion 48 of the lower flame spreader 48. Initially, the outward extending flame is confined below the plate-like portion 56 of the upper flame spreader 13, and, after impingement upon the frusto-conical portion 48, are allowed to extend upward and outward. The opening 52 surrounding the annular burner member 16 supplies air for the high rate flames. The frusto-conical portion 48 spreads and disperses the burning fuel in the outward extending flames and enhances the mixture of fuel with air to improve combustion.

Also at the high rate of operation, flame from the burner port 28 impinges on the flame sensing element 42 to maintain the element 42 in its operated condition. At the low rate of operation, the flame generated by the burner port 28 is insignificant relative to the flame from the much larger and more numerous ports 26 and hence is not illustrated in FIG. 1.

On particular advantage of the burner apparatus is that it can be employed in a system utilizing liquid propane gas. Propane gas has a much higher BTU per cubic foot content than commonly used natural gas. At the high rate of operation, the frusto-conical portion 48 in the path of the outward extending flame together with the opening 52 supplying air produce sufficient air mixture with propane to produce acceptable blue flames from propane gas. At the low rate of operation, the tabs 64 and head portions 66 extending into the openings 62 together with the supply of air from the opening 52 provide adequate mixing of air with the low rate flame to produce blue flames. Thus, the yellow flames normally associated with the standby or low rate operation of non-aerated burners for propane gas is eliminated.

Since many variations, modifications and changes in detail can be made to the present embodiment, it is intended that all matter contained in the foregoing description or shown on the accompanying drawings shall be interrupted as illustrative and not in a limiting sense.

Claims

What is claimed is:

1. A burner apparatus for operating at both low and high rates comprising

a burner member having an inlet for receiving gaseous fuel and a port for projecting non-aerated gaseous fuel in a first direction such that during a high rate of operation a high rate flame extending for at least a predetermined distance along the first direction is produced and during a low rate of operation a low rate flame deviating from the first direction in less than said predetermined distance to a second direction transverse to the first direction is produced,

a first spreader spaced in the first direction from the burner member in the path of the high rate flame for enhancing the burning of the gaseous fuel in the high rate flame,

a second spreader spaced in the second direction from the port and having an opening for allowing passage of the low rate flame, and

means disposed within the opening for dispersing the low rate flame to enhance the burning of the gaseous fuel in the low rate flame.

2. A burner apparatus for operating at both low and high rates comprising

a burner member having an inlet for receiving gas and a port for projecting gas in a first direction such that during a high rate of operation a high rate flame extending for at least a predetermined distance along the first direction is produced and during a low rate of operation a low rate flame deviating from the first direction in less than said predetermined distance to a second direction transverse to the first direction is produced,

a first spreader spaced in the first direction from the burner member in the path of the high rate flame for enhancing the burning of the gas in the high rate flame,

a second spreader spaced in the second direction from the port and having an opening for allowing passage of the low rate flame,

means disposed within the opening for dispersing the low rate flame to enhance the burning of the gas in the low rate flame,

a flame sensing element spaced from the port beyond the dispersing means in the path of the low rate flame, and

said burner member having a second port for projecting gas against the flame sensing element when the burner is operating at the high rate.

3. A burner apparatus for operating at both low and high rates comprising

a burner member having an inlet for receiving gas and a plurality of spaced ports for projecting gas in a substantially horizontal direction such that during a high rate of operation a high rate flame extending for at least a predetermined distance along the horizontal direction is produced and during a low rate of operation an upward extending flame deviating from the horizontal direction in less than said predetermined distance is produced,

a first spreader spaced in the horizontal direction from the burner member in the path of the high rate flame for enhancing the burning of the gas in the high rate flame,

a second spreader spaced above the plurality of ports and having an opening for allowing passage of the low rate flame,

means disposed within the opening for dispersing the low rate flame to enhance the burning of the gas in the low rate flame.

4. A burner apparatus for operating at both low and high rates comprising

a burner member having an inlet for receiving gas and a port for projecting gas in a first direction such that during a high rate of operating a high rate flame extending for at least a predetermined distance along the first direction is produced and during a low rate of operation a low rate flame deviating from the first direction in less than said predetermined distance to a second direction transverse to the first direction is produced,

a first spreader spaced in the first direction from the burner member in the path of the high rate flame for enhancing the burning of the gas in the high rate flame,

a second spreader spaced in the second direction from the port and having an opening for allowing passage of the low rate flame,

means disposed within the opening for dispersing the low rate flame to enhance the burning of the gas in the low rate flame,

said second spreader including a horizontal plate-like portion, and

said dispersing means including a tab projecting from the plate-like portion into the opening.

5. A burner apparatus as claimed in claim 4 wherein

the tab has an enlarged head portion within the opening.

6. A burner apparatus for operating at both high and low rates comprising

a hollow annular member disposed about a vertical axis and having a plurality of spaced outward facing burner ports such that during a high rate of operation outward extending flames are produced and during a low rate of operation upward extending flames are produced,

a first spreader annularly disposed about the annular member in the paths of the outward extending flames for promoting the burning of the outward extending flames,

a second spreader annularly disposed about the annular member above the burner ports and having a plurality of openings adjacent the annular member for allowing passage of the upward extending flames, and

means disposed in each of the openings for dispersing the upward extending flames to promote the burning of the upward extending flames.

7. A burner apparatus as claimed in claim 6 which includes

a flame sensing element,

means for mounting the flame sensing element along the vertical axis above the hollow annular member,

means for directing the upward extending flame toward the flame sensing element after passing through the openings, and

an inward facing port in the hollow annular member for directing a flame against the flame sensing element during operation at the high rate.

8. A burner apparatus for operating at both high and low rates comprising

a hollow annular member disposed about a vertical axis having an inlet for receiving gas and a plurality of spaced outward facing burner ports such that high rate streams of burning gas are projected radially outward from the annular member and low rate streams of burning gas are projected upward along the outer surface of the annular member and convergent toward the axis over the top of the annular member,

a first spreader having an upward flaring frusto-cone portion disposed about the annular member in the outward paths of the high rate streams and leg portions mounting the second spreading member on the annular member below the outward facing burner ports,

said first spreader having an opening between the frusto-cone portion and the annular member,

a second spreader mounted on the annular member and having a plate-like portion spaced above the outward facing burner ports,

said plate-like portion having a plurality of openings adjacent the annular member for passing the low rate streams of burning gas,

a flame sensing element,

means for mounting the flame sensing element on the vertical axis above the annular member in the path of the convergent low rate streams,

said annular member having an inward facing burner port for projecting a stream of burning gas against the flame sensing element during operation at the high rate, and

a plurality of projections each having an enlarged head portion extending into each of the openings in the plate-like portion for dispersing the low rate streams to enhance the burning of the low rate streams.