US3840330A

US3840330A - Round burner with radial secondary air passage

Info

Publication number: US3840330A
Application number: US00408906A
Authority: US
Inventors: J Katchka
Original assignee: Robertshaw Controls Co
Current assignee: Robertshaw Controls Co
Priority date: 1973-10-23
Filing date: 1973-10-23
Publication date: 1974-10-08
Anticipated expiration: 1991-10-08

Abstract

A burner apparatus, operable at high and low rates, has a round burner member with a plurality of circumferentially spaced burner ports formed only in part of the circumference of the burner member, leaving the remaining part of the circumference of the burner member for the radial intake of secondary air.

Description

United States Patent [191 Katchka 51 Oct. 8, 1974 ROUND BURNER WITH RADIAL SECONDARY AIR PASSAGE Inventor: Jay R. Katchka, Cypress, Calif.

Robertshaw Controls Company, Richmond, Va.

Filed: Oct. 23, 1973 Appl. No.: 408,906

Assignee:

US. Cl 431/285, 236/15 A, 431/347 Int. Cl. F23q 9/00 Field of Search 431/80, 284, 285, 347;

References Cited V UNITED STATES PATENTS 6/1900 Raupp 239/567 3,762,639 10/1973 Katchka et a1 431/285 X Primary Examiner-Edward G. Favors 1 Attorney, Agent, or Firm-Anthony A. OBrien [5 7] ABSTRACT A burner apparatus, operable at high and low rates, has a round burner member with'a plurality of circumferentially spaced burner ports formed only in part of the circumference of the burner member, leaving the remaining part of the circumference of the burner member for the radial intake of secondary air.

9 Claims, 6 Drawing Figures ROUND BURNER WITH RADIAL SECONDARY AIR PASSAGE BACKGROUND OF THE INVENTION 1. Field of the Invention The invention relates to gaseous fuel burners, and in particular, to systems employing burners operable at both high and low rates.

2. Description of the Prior Art Prior art plural rate burners employ hollow annular burner members disposed about a vertical axis with a plurality of burner ports spaced in a horizontal plane about the entire circumference of the burner member; secondary air is supplied through an opening between a frusto-conical target surrounding the burner member for entrainment in fuel projected from the burner ports against the target. Such burners sometimes have the tendency to produce a flame with yellow tips. Also such burners heat the input nipple portion to the burner which in turn heats the fuel being supplied to the burner reducing the quantity of fuel flowing into the burner member.

SUMMARY OF THE INVENTION The invention is summarized in that a burner apparatus operable at both high and low rates includes a round burner member disposed about a vertical axis and having an inlet and a plurality of circumferentially spaced burner ports which are directed radially outward from the burner member to produce a radially outward extending flame when operated at the high rate and to produce an upward extending flame when operated at the low rate, said burner ports being disposed only in a first arcuate portion of the circumference'of the burner member, and said burner member having a second arcuate portion which is free of outward directed ports to allow radial intake of air into fuel projected radially outward from the burner ports.

An object of the invention is to provide a burner having an increased secondary air intake into the burner flame.

Another object of the invention is to lessen the tendency of plural rate burners to produce flames with yellow tips at a high rate of operation.

It is still another object of the invention to lessen the heating of fuel being-supplied through an input into a burner member to minimize reduction in the rate of fuel supply to the burner.

A further object of the invention is limit the rate of radial air intake to the immediate port area adjacent a port-free area.

Additional features of the invention include the provision of an inlet disposed in an arcuate portion of the burner member, which portion is cooled by radial air intake; and the provision of a baffle to limit the amount of secondary air that is supplied to base portions of fuel exiting from burner ports adjacent a port-free section of the burner member.

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

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram of a burner apparatus having parts broken away illustrating a high rate of operation in accordance with the invention.

FIG. 2 is a top view of a portion of the burner apparatus shown in FIG. 1.

FIG. 3 is a cross sectional plan view of a burner member of the burner apparatus of FIGS. 1 and 2.

FIG. 4 is an elevational view of a broken away portion of the burner apparatus of FIG. 1 illustrating a low rate of operation.

FIG. 5 is a elevation view with portions broken away of a modified burner apparatus.

FIG. 6 is a top view of the modified burner apparatus of FIG. 5.

DESCRIPTION OF THE PREFERRED EMBODIMENT As illustrated in FIG. 1, the present invention is em- I bodied in a burner apparatus which includes a gas control device, indicated generally at 10, connected by a conduit 12 to an inlet 14 of ,a burner member, indicated generally at 16, and by a line 18 to a flame sensing ele ment 20. The burner control device 10, connected to a suitable gaseous fuel source (not shown). is capable of supplying a low pressure fuel to the conduit 12 for standby or low rate operation of the burnerapparatus and for supplying a high pressure fuel to the conduit 12 for high rate operation. The control device 10 includes thermostat facilities (not shown) which selectively controls the high rate or low rate of operation of the burner system in response to a sensed condition. In addition, the burner control 10 includes safety valve facilities (not shown) connected to the line 18 which is responsive to conditions in the line 18. for closing to terminate the supply of fuel to conduit 12in the absence of the sensing of a flame by the flame sensing element 20. A suitable control device is disclosed in U. S. Patent Application Ser. No. 98,246 by Jay R. Katchka and Henry C. Braucksiek flled on Dec. 15, 1970, now U.S. Pat.

No. 3,762,639. v

The burner member 16 includes an outer tubular sec.- tion 24 and an inner tubular section 26 coaxially ar ranged with their upper ends and lower ends suitably joined together to form an annular chamber The inlet 14 communicates with the chamber 28. A frustoconical flame target 32 has legs 34 secured to the burner member 16 and is disposed around the burner member 16 in a spaced relationship leaving an opening 36 between the burner member 16 and the target 32 to allow for free passage of air. Heat dissipating tabs 38 extend outward from the target 32. The flame sensing element 20 is mounted along the axis of the burner member 16 by a tubular spring clip support 38 mounted on a bottom plate 40 suitable secured to the burner member l6.The plate 40 has suitable openings 42 therein for allowing passage of air. The flame sensing element 20 extends above the upper end of the burner member 16 within a frusto-conical shield ,46 secured by tabs 48 to an annular shield base 50. The flame sensing element 20 is any suitable device, such as thermocouple which producesconditions, such as cur: rents or voltages, in the line 18 to operate the safety valve facilities. Spokes 51 (FIG. 4) withopenings 52' therebetween extend inwardly from the shield base to a collar 54 which is mounted on the upper end of the burner member 16 to support the shield base 50 and the shield 46. The shield 46 has leg portions 58 which support a top 60 in a spaced relationship to provide ventilation.

The burner member 16 has an upwardly and inwardly directed port 62 formed within the inner tubular section 26 for producing and directing a flame impinging upon the flame sensing element 20 at the high rate of operation.

A plurality of outwardly directed ports 66 are formed in the outer tubular section 16 substantially along an intersection with a horizontal plane below the shield base 50. As shown in FIG. 3 the burner ports 66 are formed only within an arcuate portion 68 of the burner member 16 extending around approximately 285 of the circumference of the burner member 16. The inlet 14 is located centrally within the arcuate portion 69 of the burner member 16 which does not have any ports 66 formed therein.

In operation of the burner apparatus shown in FIGS. 1, 2, 3 and 4, the thermostat facilities of the control device in response to a sensed condition, such as temperature, supplies from the gaseous fuel source either a low pressure gas or a high pressure gas to the conduit 12 to cause the respective low rate or high rate of operation of the burner apparatus. At the low rate of operation, as illustrated in FIG. 4, fuel from the ports 66 sustains flames which extend upward following the outer wall of the burner member 16 through the openings 52 between the spokes 51. Above the upper end of the burner member 16 thelow rate flames converge inward impinging upon the flame sensing element 20. At the high rate of operation, as illustrated in FIGS. 1 and 2, the high pressure fuel from the chamber 28 projects radially outward from the ports 66 while fuel from the port 62 is projected inwardly and upwardly to sustain a flame impinging upon the flame sensing element 20.

7 low rate of operation and the upward and inward extending flame from the port 62 at the high rate of operation maintain the flame sensing element operated which through line 18 maintains the safety valve facilities in the control device 10 open. In the event that the flames are extinguished, the sensing of the absence of a flame by the element 20 causes the safety valve facilities to close terminating the flow of fuel to conduit 12 to prevent the hazardous release of fuel.

The fuel projected outwardly from the ports 66 at the high rate of operation impinges upon the target 32. Air through the opening 36 is entrained in the projecting fuel which sustains flames extending outwardly and upwardly from the target 32. Referring to FIGS. 2 and 3, fuel is projected outwardly only from the arcuate portion 68 of the burner. member l6- with no fuel being projected outwardly from the port free arcuate portion 69 of the burner member 16. The resulting radial opening or absence in the outward and upward extending flames allows air to be radially drawn into the inward and upward portions of the flames above the target 32.

Also, the absence of outward projecting fuel from the port-free arcuate portion 69 results in greater radial inward flow of air in the area below the target 32 toward the port free arcuate portion 69. The provision of the port-free arcuate portion 69 of the burner member 16 and the resulting radial intake of air substantially reduces any tendency of the high rate flames to have yellow tips indicating a more complete or efficient combustion of the fuel.

The absence of burner ports in the port-free arcuate portion 69 reduces the heating of the burner member 16 in the area adjacent the inlet 14. Also the increased radial flow of air toward the area of the burner member 16 adjacent the inlet 14 causes additional cooling of the inlet 14. With the inlet 14 maintained at a lower temperature, fuel passing through the inlet 14 is heated less resulting in a greater flow of fuel through the inlet 14 into the chamber 28.

A modified burner apparatus is shown in FIGS. 5 and 6 wherein the same reference numerals are used to in-' dicate parts having substantially the same strucutre and/or function as the similarly identified parts in FIGS. 1-4. The modified apparatus includes a baffle 70 which radially extends from the shield base 50 outwardly above the flame target 32. The baffle 70 is wedge shaped (FIG. 6) and disposed to extend over the portion of opening between the target 32 and the shield base 50 which corresponds to the port-free arcuate portion of'the burner member l6. The baffle 70 extends in a horizontal plane spaced a predetermined distance above'the hoirzontal plane which intersects the ports 66 and the target 32. The radial extension of the baffle 70 and the predetermined spacing above the ports 66 and the target 32 are selected to limit the flow of air between the target 32 and the baffle 70.

In operation of the modified burner apparatus of FIGS. 5 and 6 at the high rate of operation, the baffle 70 reduces the flow of air between the shield base 50 and the flame target 32 resulting in a substantial reduction in air currents in the immediate area of ports 66 which are adjacent the, port free arcuate portion of the burner member 16. In certain circumstances, burners having port-free arcuate portions without the baffle 70 could be extinguished by a cumulative and sequential port flame outage begining at ports immediately adjacent the port-free arcuate portions due to excessive air currents generated as the result of increased radial intake of air. The baffle 70 substantially reduces any tendency of flame from ports immediately adjacent the port-free arcuate portion of the burner 16 from being extinguished by excessive air currents generated by the increased radial intake of air. The baffle 70 does not substantially reduce the radial intake of air above the baffle 70 into the inward and upward portions of the flames extending from the target 32.

. Since many variations, modifications and changes in detail can be made to the present embodiments 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.

both high and low said burner member having a second arcuate portion which is free of outward directed ports to allow radial intake of air into fuel projected radially outward from the burner ports,

a flame sensing element disposed above the burner member in the path of upward extending flames at the low rate, and

means responsive to operation at the high rate for directing burning fuel against the flame sensing element.

2. A burner apparatus as claimed in claim 1 wherein the inlet is disposed in the second arcuate portion of the burner member. 3. A burner apparatus as claimed in claim 1 wherein the first arcuate portion extends more than half way around the circumference of the burner member.

4. A burner apparatus operable at both high and low rates comprising a round burner member disposed about a vertical axis and having an inlet and a plurality of circumferentially spaced burner ports which are directed radially outward from the burner member to produce a radially outward extending flame when operated at the high rate and to produce an upward extending flame when operated at the low rate,

said burner ports being disposed only in a first arcuate portion of the circumference of the burner member,

said burner member having a second arcuate portion which is free of outward directed ports to allow radial intake of air into fuel projected radially outward from the burner ports, and

a baffle for limiting air currents in the area of ports adjacent the first arcuate portion.

5. A burner apparatus as claimed in claim 4 wherein the inlet is disposed in the second arcuate portion of the burner member.

6. A burner apparatus as claimed in claim 4 wherein the first arcuate portion extends more than half way around the circumference of the burner member.

7. A burner apparatus operable at both high and low rates comprising a round burner member disposed about a vertical axis and having an inlet and a plurality of circumferentially spaced burner ports which are directed radially outward from the burner member to produce a radially outward extending flame when operated at the high rate and to produce an upward extending flame when operated at the low rate, said burner ports being disposed only in a first arcuate portion of the circumference of the burner member,

said burner ports being substantially in a first horizontal plane,

said burner member having a second arcuate portion which is free of outward directed ports to allow radial intake of air into fuel projected radially outward from the burner ports,

an annular target disposed in spaced relationship about the burner member in the path of fuel projecting from the burner ports, and

baffle means extending toward the target in a second horizontal plane spaced a predetermined distance above the first horizontal plane.

said baffle means extending radially from the second arcuate portion of the burner member.

8. A burner system operable at a high rate and at a low rate comprising a hollow annular burner member disposed about a vertical axis and having an inlet,

control means connectable to a gaseous fuel source and including thermostat means for selectively supplying a low pressure fuel and a high pressure fuel to the inlet of the burner member, said control means havingsafety valve'means for preventing ap plication of fuel to the inlet of the burner member when closed,

said burner member having a plurality of circumferentially spaced burner ports directed outward from only a first outward facing arcuate portion of the burner member,

a frusto-conical target disposed in spaced relationship about the burner member in the path of high pressure fuel projected from the burner ports,

a flame sensing element connected to the safety valve means and extending along the vertical axis above the burner member in the path of burning low pressure fuel from the burner ports,

means responsive to the high pressure fuel for directing burning fuel against the flame sensing element,

said burner member having a second arcuate portion which is port-free and exposed radially to allow radial intake of air into fuel projected from the burner ports, and

said inlet being disposed in the second arcuate burner portion.

9. A burnerapparatus as claimed in claim 8 which includes air baffle means for limiting air flow near ports adjacent the second arcuate portion.

Claims

1. A burner apparatus operable at both high and low rates comprising a round burner member disposed about a vertical axis and having an inlet and a plurality of circumferentially spaced burner ports which are directed radially outward from the burner member to produce a radially outward extending flame when operated at the high rate and to produce an upward extending flame when operated at the low rate, said burner ports being disposed only in a first arcuate portion of the circumference of the burner member, said burner member having a second arcuate portion which is free of outward directed ports to allow radial intake of air into fuel projected radially outward from the burner ports, a flame sensing element disposed above the burner member in the path of upward extending flames at the low rate, and means responsive to operation at the high rate for directing burning fuel against the flame sensing element.

2. A burner apparatus as claimed in claim 1 wherein the inlet is disposed in the second arcuate portion of the burner member.

3. A burner apparatus as claimed in claim 1 wherein the first arcuate portion extends more than half way around the circumference of the burner member.

4. A burner apparatus operable at both high and low rates comprising a round burner member disposed about a vertical axis and having an inlet and a plurality of circumferentially spaced burner ports which are directed radially outward from the burner member to produce a radially outward extending flame when operated at the high rate and to produce an upward extending flame when operated at the low rate, said burner ports being disposed only in a first arcuate portion of the circumference of the burner member, said burner member having a second arcuate portion which is free of outward directed ports to allow radial intake of air into fuel projected radially outward from the burner ports, and a baffle for limiting air currents in the area of ports adjacent the first arcuate portion.

7. A burner apparatus operable at both high and low rates comprising a round burner member disposed about a vertical axis and having an inlet and a plurality of circumferentially spaced burner ports which are directed radially outward from the burner member to produce a radially outward extending flame when operated at the high rate and to produce an upward extending flame when operated at the low rate, said burner ports being disposed only in a first arcuate portion of the circumference of the burner member, said burner ports being substantialLy in a first horizontal plane, said burner member having a second arcuate portion which is free of outward directed ports to allow radial intake of air into fuel projected radially outward from the burner ports, an annular target disposed in spaced relationship about the burner member in the path of fuel projecting from the burner ports, and baffle means extending toward the target in a second horizontal plane spaced a predetermined distance above the first horizontal plane. said baffle means extending radially from the second arcuate portion of the burner member.

8. A burner system operable at a high rate and at a low rate comprising a hollow annular burner member disposed about a vertical axis and having an inlet, control means connectable to a gaseous fuel source and including thermostat means for selectively supplying a low pressure fuel and a high pressure fuel to the inlet of the burner member, said control means having safety valve means for preventing application of fuel to the inlet of the burner member when closed, said burner member having a plurality of circumferentially spaced burner ports directed outward from only a first outward facing arcuate portion of the burner member, a frusto-conical target disposed in spaced relationship about the burner member in the path of high pressure fuel projected from the burner ports, a flame sensing element connected to the safety valve means and extending along the vertical axis above the burner member in the path of burning low pressure fuel from the burner ports, means responsive to the high pressure fuel for directing burning fuel against the flame sensing element, said burner member having a second arcuate portion which is port-free and exposed radially to allow radial intake of air into fuel projected from the burner ports, and said inlet being disposed in the second arcuate burner portion.

9. A burner apparatus as claimed in claim 8 which includes air baffle means for limiting air flow near ports adjacent the second arcuate portion.