US 3510240 A
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1970 E. T. RHINEHART 3,510,240
' PILOT BURNER Filed Oct. 25, 1968 48 L EUW" vz i 4 ifi 'limml 44 v0 4 22 20 INVENTOR. EARL 2' RH/NEHHRr United States Patent 3,510,240 PILOT BURNER Earl T. Rhinehart, Apison, Tenn., assignor to Magic Chef, Inc., Cleveland, Tenn. Filed Oct. 25, 1968, Ser. No. 770,771 Int. Cl. F23d 13/24 US. Cl. 431-350 Claims ABSTRACT OF THE DISCLOSURE A block of metal having two tubes terminating adjacent each other. The block has one passageway for directing gas or gas and primary air to one tubehaving a pilot burner head at its outer end and another passage way for directing pressurized secondary air along the other tube. The block is formed to provide adjustable communication between the two passageways and the outer ends of the tubes are partially enclosed by a gas and air confining hood.
Background of the invention This invention is in the field of gas pilot burners particularly for use in self-cleaning gas ovens or with any powered burner application.
The concept of a self-cleaning gas oven is relatively new and among the problems presented is the maintenance of an adequate pilot flame during self-cleaning cycles. Furthermore, the maintenance of a suitable pilot flame during normal baking and broiling operations, particularl with powered burners, has heretofore presented problems due in part to the fact that during any oven operation there is a scarcity of oxygen for maintenance of a pilot flame and opening and closing of the oven door tends to extinguish the pilot. The term powered as used herein refers to burners supplied with combustion air from a source of air under pressure.
Summary of the invention The present invention contemplates a powered gas pilot burner, that is, a pilot burner that is supplied with air from a pressurized source of air independent of the ambient atmosphere in or adjacent an oven. In general, the invention comprises a burner having means to supply the same with fuel, with or without primary air, and conduit means for conducting air under presure, from a suitable blower, to the pilot burner. The pressurized air conduit discharges air closely adjacent the burner head to ensure an adequate supply of oxygen and adjustable means are provided for permitting some of the pressurized air to enter the gas conduit leading to the pilot burner head to supply primary air to mix with the gas fuel before it reaches the burner head. The structural arrangement comprises a base block having inlet and outlet ports and suitable tubing leading to and from the same whereby to provide the contemplated connection between the pressurized air and the gas line and to deliver pressurized air to the region about the pilot burner head.
Brief description of the drawings FIG. 1 is an elevational view of a gas pilot burner incorporating the present invention;
FIG. 2 is a view of the structure of FIG. 1 as viewed from the right side thereof;
FIG. 3 is an end view of the structure of FIG. 1' as viewed from the top of that figure; and
FIG. 4 is a transverse sectional view taken along the line 44 of FIG. 1.
Description of a preferred embodiment In the drawings, numeral 2 indicates a base structure which is shown as a block of metal or the like having a 3,510,240 Patented May 5, 1970 gas inlet port 4 and a gas outlet port 6 therein with a passageway 8 providing communication between the inlet 4 and outlet 6. A pressurized air inlet port 10 is formed in one end of the block 2 and an angled passageway 12 provide communication between the air inlet port 10 and an air outlet port 14. A suitable air conduit 16 and fitting 18 are provided for the delivery of slightly compressed air to the inlet port 10. Likewise, a gas conduit 20 and fitting 22 provide for delivery of gas to the inlet port 4.
A gas tube 24 extends outwardly from the gas outlet port 6 and terminates in a burner head 26 of more or less conventional construction. The details of the burner head 26 are not shown since they are well known to those skilled in the art but the burner head provides a suitable outlet, for example, as shown at 28, at which a gas and air mixture is to be burned.
A secondary air tube 30 extends from the air outlet port 14 and is so configured as to position its outer end 32 adjacent the burner head 26. The outer end 32 is preferably open, as at 34, to discharge secondary air issuing near the burner head 26. A hood structure, indicated generally at 36, is formed preferably of sheet metal and partially encompasses the burner head 26 and the outer end 32 of the air tube to confine the air issuing from open end 34 to a region surrounding the burner head 26 and thereby ensure that the secondary air will be available to the pilot flame. As shown, the hood 36 is provided with suitable flange portions such as 38 and 40 for mounting a flame sensor or mercury operated gas valve near the pilot burner.
The passageways 8 and 12, in base block 2, are further interconnected by a small transverse passageway 42. A screw threaded valve member 44 is threadedly received in an opening 46 in the block 2 and can be adjusted to provide any desired degree of communication between the passageways 12 and 8 whereby to regulate a quantity of pressurized air that can be directed into the passageway 8 to provide primary air for the fuel directed to the burner head 26. If desired, the block 2 may be further provided with an opening 48 providing communication between the passageway 8 and ambient atmosphere to directly induce primary air into the gas supply. Obviously, the valve member 44 may be adjusted to completely cut off flow from passageway 12 to passageway 8 and thus condition the pilot burner for conventional operation, particularly in the event that a failure may occur in the pressurized air supply. When pressurized air is available, the valve 44 may be opened to the desired degree to provide adequate primary air to the pilot burner.
By the above described construction applicant has provided a highly eflicient, powered pilot burner found to be highly reliable under adverse and unusual conditions within an oven.
While a single specific embodiment of the invention has been shown and described, the same is understood to be merely exemplary of the principles of the invention.
1. In a gas pilot burner; a pilot burner head; means defining a passageway for directing gas to said head; means defining a second passageway for directing secondary air under pressure to a position adjacent said head; and adjustable orifice means providing communication between said first and second passageways whereby a se lective quantity of air under pressure may be directed into said first passageway.
2. A pilot burner as defined in claim 1 including a port providing communication between said first passageway and ambient air whereby primary air may be drawn into said first passageway by flow of gas therein.
3. A pilot burner comprising: a block having a pair of inlet ports and a pair of outlet ports therein, first and second passageways in said block respectively connecting a first inlet port to a first outlet port and the second inlet port to the second outlet port; a gas tube secured to said block, extending outwardly from said first outlet port and having a pilot burner head at its outer end; a secondary air tube secured to said block, extending outwardly from said second outlet port and having an outer end adjacent said burner head; further passageway in said block, communicating with said first and second passageways; and adjustable valve means in said further passageway.
4. A burner as defined in claim 3 wherein said valve means comprises: a threaded bore intersecting said further passageway and extending to the exterior of said block and a screw member threaded through said bore into said further passageway fior selectively changing the effective cross-sectional area thereof.
5. A burner as defined in claim 3 including hood means partiallylencornpassing said burner head and the 4/1925 Osthoff 431-350 X 5/1948 Goehring l37597 CARROLL B. DORlTY, 111., Primary Examiner r US. Cl. X.R. 137 -597; 431-454