US 4,559,009 AGranted

Aggregate dryer burner

AssigneeHauck Manufacturing Company

InventorsJohn A. Marino, Roderick G. Strohl, Jr., Robert B. Yost

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Abstract

A swirl-type internal flame recirculation burner as used to fire asphalt plant aggregate dryers, air heaters and calcining kilns and method includes an atomizer assembly for swirling primary air in two concentric streams with the inner stream swirling more rapidly than the outer stream. Fuel oil is blast atomized in a continuous sheet into the inner stream without prefilming and then is shear atomized as the inner and outer streams violently intermix. The burning and swirling fuel and primary air mixture recirculates upstream along the burner axis. Secondary air is swirled in the same direction as the primary air and surrounds the primary air stream to promote further mixing and internal recirculation. A metal frustro-conical flame holder surrounds the burner head to stabilize and shape the recirculation flame and shield low-burn flames from tertiary air. The swirl of the secondary air is also adjusted to shape the flame. The burner may also be fired on gas or a combination of gas and oil.

Claims20

Dependent claims

A burner including an axial fuel pipe;

a fuel atomizer at the downstream end of the pipe;
a primary air pipe coaxial with the fuel pipe, surrounding the fuel pipe and extending upstream from the fuel atomizer;
a secondary air pipe coaxial with the fuel pipe, surrounding the primary air pipe and extending upstream from the atomizer;
said secondary air pipe having an exit portion extending parallel to the axis of said fuel pipe;
means for swirling primary air in a first direction;
said means for swirling primary air including means adjacent said fuel atomizer defining two separate concentric swirl passages dividing the primary air into two flow masses, the first of said primary swirl passages configured to accelerate the flow of a first primary air mass therethrough in a swirling motion, the second of said primary swirl passages configured to impart a slower swirling motion to a second primary air mass flowing therethrough such that said second air mass flows faster axially than said first air massto thereby provide strong sheer atomization of fuel near said fuel atomizer upon engagement of the respective swirling air masses;
the inner one of said separate concentric primary swirl passages having an exit portion diverging away from said atomizer and the outer of said primary swirl passages having an exit portion extending parallel to the axis of said fuel pipe;
means for swirling secondary air in said first direction, said secondary air swirling means being adjustable to provide a varying degree of swirl in said secondary air;
and
a damper assembly joining the primary and secondary air pipes including an outer duct connected to said primary and secondary air pipes at an angle such that primary and secondary air respectively are directed with a minimum pressure drop to each respective primary and secondary swirling means, the duct having an upstream mouth adapted to be connected to a souce of combustion air, an interior wall dividing the duct into a primary air passage and a secondary air passage, both passages communicating with the upstream duct mouth, the primary air passage communicating with the primary air pipe, the secondary air passage communicating with the secondary air pipe, a first damper within the primary air passage to control the flow of primary air therethrough, a second damper within the secondary air passage to control the flow of secondary air therethrough.

7 more elements

A swirl type burner comprising an axial atomizer having first swirl generating means for swirling an inner flow of primary air in a first direction, an oil delivery passage opening into the swirled first flow of air, second swirl generating means located outwardly and surrounding the first swirl generating means for swirling a second flow of primary air in said first direction, the downstream mouths of said first and second means being located adjacent to each other so that the swirled first and second flows are free to intermingle following discharge from the mouths to thereby provide strong sheer atomization of fuel near said atomizer;

the mouth of said first swirl generating means having a portion diverging away from said atomizer and the mouth of said second swirl generating means having a portion extending parallel to the axis of said atomizer;
outer swirl generating means surrounding said atomizer for swirling in said first direction a third flow of air comprising secondary air;
said outer swirl generating means having a exit portion extending parallel to the axis of said atomizer;
means for directing combustion air with a minimum loss in pressure to each of the first and second swirl generating means and to the outer swirl generating means;
a gas delivery system including a gas pipe having an annular gas outlet located between the atomizer and the outer swirl generating means so that said system delivers gas between the swirling inner flows of primary air and the outer flow of secondary air, each of said atomizer, outer swirl generating means and gas delivery system having downstream ends defining a burner head;
and
a frustro-conical member surrounding the burner head and secured to the outer swirl generating means, said frusto-conical member including an outer air deflector surface extending from the outer swirl generating means a distance radially outwardly and axially downstream past the burner head for deflecting downstream flowing air from the burner heed and an inner surface for shaping the flame on the burner head.

4 more elements

A burner including an axial fuel pipe;

a fuel atomizer at the downstream end of said fuel pipe;
a primary air pipe coaxial with and surrounding said fuel pipe and extending upstream from said atomizer;
a secondary air pipe coaxial with said fuel pipe, surrounding said primary air pipe and extending upstream from said atomizer;
means adjacent to said atomizer for swirling primary air including means defining a first swirl passage and a second swirl passage, said first and second swirl passages being oriented concentrically relative to each other, each of said first and second swirl passages being configured to accelerate the primary air flowing respectively therethrough in a swirling motion in the same direction and at a different degree of swirl and in an axial direction at a different flow rate than the other said swirl passage, thereby to promote strong sheet atomization of fuel near said atomizer;
the inner one of said primary swirl passages having an exit portion diverging away from said atomizer and the outer of said primary swirl passages having an exit portion extending parallel to the axis of said fuel pipe;
means for swirling secondary air in the same direction as the swirling primary air flows, said secondary air swirling means being adjustable to provide a varying degree of swirl in said secondary air;
said secondary airpipe having an exit portion extending parallel to the axis of said fuel pipe;
and
means for directing combustion air with a minimum loss in pressure to the respective primary and secondary swirling means.

6 more elements

Dependencies are inferred from the claim text.

Facts

Application: 06/649,975Filed 12 Sep 1984 · continuation
Priority: 9 Jun 1980
Granted: 17 Dec 1985
Term ends: Not estimatedThe source records don’t support an estimate.

Classification6 codes

F23D 14/24
With separate air and gas feed ducts, e.g. with ducts running parallel or crossing each other: at least one of the fluids being submitted to a…
F23D 11/14
Characterised by the shape or arrangement of the outlets from the nozzle: with a single outlet, e.g. slit
F23D 17/002
Burners for combustion simultaneously or alternately of gaseous or liquid or pulverulent fuel: gaseous or liquid fuel
F26B 23/02
Heating arrangements: using combustion heating