US2632501A - Fluid fuel burner - Google Patents

Description

s Sheets-Sheet 3 Filed Oct. 6, 1949 mBaK Patented Mar. 24, 1953 FLUID FUEL BURNER.

Edward K. Clark, Baldwin, N. Y., assignor to Peabody Engineering Corporation, New York, N. Y., a-corporation of New York Application October 6, 1949, Serial No. 119,849

. 7 Claims.

more particularly to burners of the type which include a burner tube, air supply means, burner throat, and fuel supply means.

An'object of the present invention is to provide a. fuel burner ofthe above type having novel and improved characteristics.

Another-object is to provide, in a burner of the above" type, improved means for controlling the air distribution to the fuel at the burner throat.

Another-object is to provide improved means for controlling the flame shape.

Another objectis to provide a burner of the abovetype which may be readily used with furnace walls having openings larger than the minimum'desired burner throat diameter.

Another object is to provide a burner of the above type in which the burner throat tiles are carried by the burner tube and form a part of the burner unit.

Another object is toprovide a burner of. the

' above type in which the flow of the air supplied to the flame is controlled without the use of peripheral air doors or vanes.

Another object is to provide a fully automatic wide range burner of the mechanical atomizer type. l 1

Various other obj'ects and advantages will be apparent to those skilled in the art.

'Inoneembodiment the burneryaccording to the present invention, is formedwith a cylindrical burner tube which registers with the openingi'nthefurnace wall and housesthe atomizer assembly. The burner tube is larger indiameter than the minimum throatopening. An adjustable throat sleeve isdi'sposed in alignment with thethroat opening. Thissleeve is connected with andjspaced inwardly from the peripheral wall of jt'he'burnertube and has an unobstructed opening through which air is supplied to the throat. The sleeve-opening, being smaller than the internaldia'meter of the burner tube, causes the tube to actz'as' a plenum chamber for the air from theforced draft fan and distributes the air uniformly around the difiuser and into the fuel in theburner throat.- The-direction of the air and the flame shape may be varied by axial adjustmentxof the sleeve.

Theai'r is supplied to-the forward end of the burner tube and'a perforated baffie plate serves to break-up theair stream and distribute the same uniformly acrossthe inlet opening of the burnertube- In one: embodiment the sleeve carries'a ring of throat tile having, an opening registering with the-burneropening the-furnacewall. In this way the minimum opening may be varied as desired by replacing the throat tile in the tube sleeve and without alteration of the opening in the furnace wall.

The fully automatic control includes a modulating control motor responsive to steam pressure in the boiler and connected to vary the airand fuel. supply in accordance with the heat requirements. A timed controller is also provided to start the fuel and air feed motor, and gas-electric ignition apparatus, and open the oil supply valve only after the feed oil has been preheated to the required temperature, and to shut down the burner in response to excess steam pressure, low boiler water level, low gas pressure or absence of burner flame.

The nature of the invention will be better understood by referring to the following description taken in connection with the accompanying drawings in which certain specific embodiments have been set forth for purposes of illustration.

In the drawings:

Fig. 1 is a longitudinal section through a burner embodying the invention;

Fig. 2 is a front elevation thereof;

Fig. 3 is a partial longitudinal section similar to Fig. 1, showing a further embodiment of the invention; and

Fig. 4 is a schematic diagram of a fully automatic control system.

Referring to the drawings more in detail, the invention is shown in Figs. 1 to 3 as comprising a cylindrical burner tube Ill having a front flange I I which is bolted by bolts 52 to a front plate M which forms a front closure for the burner tube and is provided with a central hub l5 through which an atomizer barrel it passes. The atomizer barrel It may be of any standard type having a tip H which, in the case of an oil atomizer, is adapted to direct a spray of oil to the combustion zone, or, in the case ofa gas or pulverized fuel burner, is adapted to supply fuel for combustion to the combustion zone. A diffuser IQ, of the usual form, is providedlfor controllingthe shape of the atomized fuel spray, or of the'gas stream and thezoneof contact between the fuel and air.

Air for combustion is supplied-to the tube [0 through a duct 20 which communicates with a suitable source of air under pressure and discharges into an opening 2| in the peripheralv wall of the burner tube l0. In orderto control; the opening 21, and the distribution of the air therethrough a baffle 22 is provided which isv shown in the form of a slide which iscurved to conform to theperiphery of the burner tube It andsli'des axially of the burner tube in channels 23 which are attached thereto. The bafile 22 is provided with a plurality of openings 24 to diffuse the air which are disposed over the surface thereof and through which the air passes on it way from the duct 26 to the burner tube Ill. The baflle 22 may be slidably adjusted as desired so as to cover all or a portion of the opening to the burner tube.

At its rear end the burner tube it is provided with a flange 25 which is bolted to a similar flange 26 of a gas ring 21. The gas ring is also provided with a flange 28 which is bolted to a front plate 29 forming a part of the furnace wall. The gas ring 21 is provided with a plurality of apertures 3i] through which gas is supplied to the burner throat and communicates with a gas supply duct "3| by which gas is supplied thereto. It is to be understood of course that, if the gas ring is not required in any particular instance, it may be omitted and the flange 25 of the burner tube may be bolted directly to the furnace front plate 29.

The furnace wall is shown as lined with refractory 32 and as having a ring of tile 33 forming a refractory burner throat which flares outwardly into the combustion chamber.

The burner tube also carries at its rear end adjacent flange 25 an inwardly extending radial flange 35 to which a cylindrical flange 35 is attached. A throat sleeve 31 is slidably held within the flange 36 and is provided with a plurality of holes which may be engaged by a suitable tool passed through the front plate Hi for adjusting the axial position of the sleeve. The sleeve 3? and flange 35 are spaced inwardly from the burner tube Ill. The sleeve 31 has an unobstructed forward opening 38 which is of lesser diameter than the diameter of the burner tube Ill. The burner tip I! and diffuser I9 are disposed axially within the chamber formed by the sleeve 31 and flange 36.

Operation In the operation of this device it is noted that all of the air supplied through the duct 29 and opening 2| into the burner tube I undergoes a change of direction as it advances axially to the burner throat. The air then undergoes a further change in direction as it approaches the opening 38 ofthe sleeve 31 and at least a portion of the air from the burner tube I0 flows inwardly toward the opening 38. Hence the air is directed in a generally inward and axial direction toward the diffuser l9 and is caused to mix with the fuel spray emerging from the difluser.

r The reduced diameter of the opening 38 serves to increase the pressure within the tube 10 and causes the same to act as a plenum chamber for holding and distributing the air It also causes the air to be distributed uniformly around the periphery of the diffuser so that a uniform mixture with the fuel is obtained. By varying the length of the sleeve 31, that is by sliding the same in the flange 3'6, 'thepressure within the burner tube 10 and the resulting direction of air flow through the sleeve to the diffuser may be varied, thereby serving as a control for the shape of the flame. The adjustment may be made such that the flame does not strike either the refractory burner throat or the walls or floor of the furnace.

'The apertured plate 22 also serves to diffuse the air and prevent stratification thereof. Although the direction of admission of the air is shown as substantially radial, nevertheless some rotation will take place in one direction or the other as the air changes its direction and passes axially to the burner throat. The rotation may be controlled by pre-setting the position of the baffle 22 and of the sleeve 31. This construction permits the burner to be used efficiently and permits the desired flame shape to be maintained at all loads withinits range. The burner is thus particularly suited for use with a wide range atomizer of the type shown in the Peabody Patent No. 1,628,424 dated May 10, 1927, although it is also applicable to a gas or pulverized fuel burner. The throat gas ring 21 may of course be omitted if desired.

Fig. 3

Referring to Fig. 3 the gas ring is omitted and the flange 25 of the burner tube It is bolted directly to the furnace front plate 29. In this embodiment a tile supporting ring 40 is provided having a flange 4| which is bolted between the flange 25 and the front plate 29 and which carries a sleeve 42 which is slidable axially thereon and is provided at its forward end with a radial flange 43 forming an internal shoulder and an axial flange 44 having a central opening 45. In this embodiment a ring of throat tile 46 is mounted in the supporting ring 40 and is formed with an internal conical opening 41 which registers with and forms an extension of the conical opening 48 in the refractory throat ring 49 which is set into the refractory furnace wall 50. It is to be understood that the throat tile 46 may be made of any desired shape so that the minimum desired internal diameter 5| of the throat may be selected. The sleeve 42 may be axially adjusted so that the radial flange 43 rests against the forward end 52 of the throat tile 46 or it may be shifted forwardly as indicated to increase the effective length of the sleeve. The diameter of the flange 44 is such that it forms a continuation of the Passage formed by the inner surface 5| of the throat tile 46, An atomizer barrel l6 having a tip I! and a diffuser [9 may be provided similar to that described in connection with Fig. 1.

The operation of this form is similar to that above described except that in this embodiment the burner is not limited to the size of opening provided in the furnace wall 50. Hence the burner may be used with any standard furnace wall opening and for purposes of adjustment it is only necessary to unbolt and remove the burner tube and replace the ring of tile in the holder 40 with a ring having the desired internal diameter and throat shape.

The fully automatic control system illustrated in Fig. 4 includes an automatic temperature controlled fuel pumping and heating system 55 which is of any standard type and may include a thermostatically controlled electric heating unit for preheating and a steam heat exchanger for maintaining the oil temperature during the burner operation. The heater receives oil from a fuel oil supply line 56. The pumping and heating system 55 includes an oil pump which is driven by a feed motor 58. Air is supplied to the duct 20 by a blower 51 which is also driven by the feed motor 58.

The preheated oil is supplied by a line 59 through a solenoid operated valve 60 to the atomizer l6 and the return from the atomizer is fed through a return line 6|, controlled by a variable opening modulation valve 62, to the suction side of the feed pump included in the pumping and heating system 55 or to the fuel oil supply reservoir.

A differential valve 63 maintains a constant pressure differential acrossxthe atomizer as destfibeq intheGraham Pate tr s2g952 dated September 29, 1931. The system is also adaptable for operationwith a constant differential air; duct- 28 which controls the quantity of air supplied to the burner. Hence a uni-control of both the air and fuel is maintained in accordance with the load requirements. The modulating motor 64 is connected to be actuated in response to a variable steam pressure controller 61 and is arranged to vary the burner load so as to maintain a constant steam pressure.

The burner shown in Figs. 1 to 3 is particularly suited for such a control as it is stable over a wide range of variation in both air and fuel and requires no internal adiustments for different loads.

A gas-electric ignition system indicated by an igniter 10 supplied by a gas line H controlled by a solenoid valve 12 and having igniting electrodes fed by an electric line 13, is positioned to start the ignition of the burner. The presence or absence of a flame when the burner is operating is detected by a photoelectric flame detector l5.

The starting is controlled by a starter relay 16 which is connected to be energized by an oil temperature switch 11 which is thermostatically controlled in response to the output oil temperature of the heating system 55, a high pressure steam switch which is adapted to open when an excessive steam pressure is developed, a low water switch which is adapted to open when the water in the boiler falls below a given level, and a gas pressure switch which is adapted to open when the gas pressure in the ignition gas line 1| falls below a given value during the ignition period.

' The switches 11 to 80 are connected in series so that opening of any one of the switches shuts down the burner and all must be closed before the starter relay (6 is energized.

The starter relay 16 is connected to start the air and fuel feed motor 58. It is also connected by a line 8| to open the solenoid actuated valve 12 in the ignition gas supply line H, and to the line 13 to energize the ignition electrodes.

The starter relay I6 also energizes a timed relay 82 which is connected by a line 83 to open theoilfeed valve 60 a predetermined time after the feedmotor 58 and the ignition system 10 have been started.

The timed relay is also connected by a line 84 to set the modulating motor 64 in minimum load condition and to allow the load to be increased gradually after ignition to the value called for by the steam pressure controller 61. The flame detector I is connected to the timed relay 82 by a line 85 and is adapted to shut down the burner if ignition does not take place within a given time or to shut off the ignition and gas supply a predetermined time after starting. It also shuts down the burner at any time in response to flame failure.

It will be noted that the above described system is fully automatic as to starting, shutting down and re-starting and also as to burner load, which with the burner disclosed herein is capable of variation over a wide range.

Although a specific embodiment has been shown for purposes of illustration, it is to be understoodthat the invention-is not to be restricted thereto, but may be adapted for various uses and th t han es an mediiieatiens may t -ma and havin'gan air inletv opening at itsforward end for the admission of airfor combustion and adapted to supply saidaii with a substantially straight line flow to a burner opening at its rearward end, a sleeve disposed within said tube at its rearward end to form a burner throat of restricted cross-sectional area, said sleeve having a smooth interior surface and having an axial air inlet opening at its forward end offset inwardly from the periphery of said tube to form an annular chamber open at its forward end to the air stream in said tube and being sealed to said tube at its rearward end to prevent passage of air therebetween into said burner opening so that the air from said tube is caused to flow inwardly as well as axially in passing from said tube to said burner throat, and means independent of the combustion air and located in said sleeve for injecting fuel into said throat in a direction substantially transverse to the axis of said sleeve so as to mix uniformly with the combustion air in said throat.

2. A fuel burner as set forth in claim 1 in which said fuel injection means comprises a barrel having a fuel atomizing tip positioned axially of said sleeve with said tip disposed in said sleeve and a diffuser on said barrel adjacent and in advance of said tip to shield said tip from the air stream and to deflect the air toward the periph cry of said throat for mixing with said fuel.

3. A fuel burner, as set forth in claim 1, in which said sleeve is slidably mounted for axial adjustment independently of the fuel admission means for adjusting the effective length of said burner throat.

4. A fuel burner, as set forth in claim 1, in which said first air inlet opening is disposed in the periphery of said tube and adjustable baffle means is disposed in said first air inlet opening and arranged to control the flow of air through said opening.

5. A fuel burner, as set forth in claim 1, in which said first air inlet opening is disposed in the periphery of said tube and a bafile plate is disposed in said first air inlet opening and arranged to control the flow of air through said opening, said baiile plate being slidably mounted for adjustment in said opening.

6. A fuel burner, as set forth in claim 1, in which said first air inlet opening is disposed in the periphery of said tube and a perforated baflie plate is disposed over said first air inlet opening and arranged to diffuse the air supplied to said tube and to control the-flow of air through said opening, said baffle plate being slidably mounted for axial adjustment along said tube.

7. In a fuel burner, as set forth in claim 1, a ring of refractory throat tile carried by said sleeve at its rearward end, said tile having an opening flared outwardly in a rearward direction to register with the burner opening.

EDWARD R. CLARK.

(References on following page) REFERENCES CITED Number 3 The following references are of record in the 2,076,768 file of this patent: g'ggggg UNITED STATES PATENTS 213961867 Number Name Date 2,439,554

464,850 Burns DEC. 8, 1891 2,485,656 1,428,574 Woolley Sept. 12, 1922 1,535,166 Leconte et a1. Apr. 28, 1925 1,824,952 Graham et a1 Sept. 29, 1931 10 Number 1,914,355 Argyle et a1 June 20, 1933 '8 Name Date Denison Apr. 13, 1937 Dickey Aug. 22, 1939 Nagel Sept. 26, 1944 Mason -1. Mar. 19, 1946 Anderson Apr. 13, 1948 Raskin Oct. 25, 1949 FOREIGN PATENTS 1 Country Date Great Britain Mar. 1. 1934

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