US1979784A - Burner for the firing of furnaces - Google Patents

Description

1934- I w. A. WOODESON 4 BURNER FOR THE FIRING OF FURNACES Filed Dec. 13, 1932 s Sheets-Sheet 1 1934- w. A. WOODESON BURNER FOR THE FIRING OF FURNACES Filed Dec. 13, 1932 3 Sheets-Sheet 2 Nov. 6, 1934. w. A. WOODESON 1,979,784

' BURNER FOR THE FIRING OF FURNACES Filed Dec. 13, 1932 3 Sheets-Sheet 3 Patented Nov. 6, 1934 BURNER FOR THE FIRING OF FURNACES William Armstrong Woodeson; Gateshead-on- Tyne, Eng-land Application December 13, 1932, Serial. No. 647,017 In Great Britain August 22, 1932 Claims. (Cl. 11-0-104 Although the performance of burners such as those of my pending" application: Serial No. 449,526 filed May 3, :l930 and Letters Patent No. 1,885,067 is very satisfactory, the equipment is recognized to-be-capable-of improvement and the present invention-is the outcome of considerable;experimentationdirected-largely: to the feature of air distribution,-one of the-results being to produce a burner specially adapted for firing in' a horizontalposition with. the. minimum of refractory materialsin the furnace tube. An important feature consists in injecting parts of the required secondary supplyof air. as jets well into the centre of the streamof fuel and primary air discharged intothe burner through a Venturi tube or its equivalent, liberation. of suchinjected air occurring in-a directionsubstantially perpendicular to-the direction of. flow and only after it has been mechanically.-.constrained and conducted across the stream for .a considerable distance. The injecting means ineifectconstitute bafiies encountered by the stream soon after leaving the Venturi tube or feed supply pipe and before it reaches the usual deflector and the turbulence due to such baifies is. augmented by the issuing secondary air jets; The secondary air is admitted to the :burner from a common chamber through .two=independently controllable se ries of cpenings and the airinlet to this chamber is in turn controlled-by. a member which although angularly adjustable is so shapedcasto continue to give to. air a bias towards the said openings which control theqnantity of air entering the various .parts' of the. burner.

In the accompanying drawings Fig. 1 is a front elevation and Fig. 2 a longitudinal section of the improved'equipment for use withpulverized fuel. Fig. 3 is a view'similarto Fig. 2 of parts modified to enablertheequipmentto be'used with liquid fuel.

Referring first to/Figs. 1 and 2, a furnace front is employed comprising a casing 1 adaptedto be bolted to thefurnacewith theaid say oftbifurcated lugs 2 spaced apart by. 90 around the flange 3, and having an upper wall l which is'curved to formwan elbow-like continuationlof: a verticalsecondary air inlet duct 5. A platefi bolted to the said casing has an ash dooropening 7, an opening 8 to receive the-burnersetting 9 and an opening 10 leading.- to the duct continuation aforesaid, .such. last referred-t0 opening being controlled by alflapivalve 11 which when closed is: vertical but. can 1 be zturnednhingewise. about a horizontal axis 12 arranged transversely or the burnerH-to-admit more or lessi air toa casingt13 removably secured to the plate 6, said casing enveloping part of. the burner and setting and being completed by a cover 14- which carries the primarypair and fuel connection or Venturi tube 15 as well as an inspection eye 16, and controlling gear-for the secondary air supply. The interiorsofthe.casingl isso "ledged as to enable refractory materialv 1'7 to, be built-in between the burnersetting 9 and the casing in order to protect both frorn' being damaged by flame; Proceeding: from the cover 14' the burner comprises a cylindrical body 18 extendingto sayhalf the depthlof the casing-13 which'receives the secondary "air; followed by 1 two concentric cylindrical lwalls:19',i.20 ofxdifirent axial :length, the shorter: wallrl nofxlarger diameter being fixed toithei burnernsetting- 9 and the longer wall-20 of smaller diameter extending withclearance into tHeburnersettin'g; so asto form'an annular space 21. An annular set of. ports 22 is provided in the burner'to admit air around the primary air and fuel connection'1or"Venturi: tube 15 and a similariset. oi -port's: 23 is. provided to admit air to the annular space 21 referred to from which it may escape-in part through an-annular gap (24. Extending inwards from the said annular space 21 are a number of nozzles 25. or an injection tubes, said-tubes being arranged in any convenientway-suchas in'one or more annular series, each tube being radial: Or thetubes, which may be of equal or unequal lengths might be hellcally arranged; In any case-they are distributed between the Venturi tube: 15 and. a longitudinally adjustable deflector 26 complete with flare 2'7 fitted in the mouth of the burner.

The two annular sets of ports 22', 23' in the burnerare independently adjustable by separate ported sleeves 22 '23 which may be rotated from the-outside thus enabling; the secondary air entering-the burner to be controlled-to a very fine degree; it beingpossible-to force the greater quantity through the air injection tubes 25 into th'eztcen-tre of the fuel stream if desired-while a minimum of: air is. allowed to enter the burner throughthe: remaining ports;

' In-the illustration; the rotation of the sleeve 23f -isshown as eiie'cted'by a spurwheel 28up0n a1spin-d1e'29 journalled in the cover 14- and operated by a hand Wheel 30 the wheel 28 meshing with teeth :23 'upon the sleeve." A hand wheel-31 is similarly geared to the sleeve 22 which is toothedat 22b; Theleffect of the injection tubes 25 is-enhanced by'iorming theflapvalve 11 with a concave curved surface ll ufacingthe elbow extension! into which it extends when closed,

the free edge ll terminating at a wall 11 concentric with the pivotal axis 12 of the valve, there being little or no increase in air delivery until the free edge 11 leaves the elbow extension 4, at which time the curved surface 11 acts, and will thereafter continue to act, with further opening movement, to direct air smoothly towards the ports 22, 23 thereby guiding it, without forming eddies, to the various parts of the burner. The pivoted flap valve 11 can be adjusted, and may be operated in any convenient way by any suitable means such as a lever handle 32 co-operating with aslotted guide 33 to which it can be clamped at any desired position by a nut 34.

Regulating and admitting the secondary air into the burner in the way described ensures a good mixing of air and fuel which results in rapid and complete combustion.

The adjustable deflector 26 and flare 27 gives the operator complete control over the velocity of air and fuel being discharged from the burner into the furnace, and enables the point at which the coal commences to ignite to be fixed immediately in front of the burner mouth and thus protect it from damage by the flame.

This control is very useful in case of ship installations where the bunker coal may vary greatly in percentage of volatile content.

With certain coal which has a very high volatile content the fuel ignites very readily and the flame may commence inside the burner, and cause damage to it.

This can be overcome by drawing the deflector and flare up further into the burner which can be done by a pull applied to a draw rod 35 passing through the cover 14 thereby increasing the velocity at the burner mouth and carrying the point at which combustion commences just in front of the burner mouth where no damage to the burner can take place.

36, Fig. 2, is a conical air director associated with the ports 22, an aperture 3'7 therein being provided to avoid obstructing the view through the inspection eye 16. 1

The burner described, suitable for pulverized fuel can also be adapted to oil fuel firing, as indicated in Fig. 3 where the oil fuel burner 38 is placed through the centre of the burner with the sprayer tip .39 inside the flare 27 of the deflector 26 the flame being controlled by adjusting the positions of the deflector 26 and oil fuel burner in an axial direction up or down the burner. Except in these respects the form of device shown in this figure is the same as that shown in the 1 other views.

What I claim is:-

1. In a furnace firing equipment, a tubular conduit, a Venturi tube for discharging a mixture of air and fuel into said conduit, an air chamber surrounding said conduit, a plurality of radially arranged air nozzles extending well into said conduit at a point beyond the discharge of the air and fuel stream into the conduit and forming a communication between the air chamber and the interior of the conduit, a housing surrounding both the conduit and the air chamber and provided with a plurality of ports some of which have direct communication with the conduit and others of which have communication with the conduit through the air chamber and the aforementioned nozzles, an air inlet to said housing, and a valve for controlling the inlet ofair to the housing, the parts operating as and for the purpose described.

2. A furnace firing equipment of a construction such as defined in claim 1, wherein independent controls having independent operating means are provided for controlling the passage of air through the ports which have communication directly with the conduit and through the ports which have communication with the conduit through the air chamber and air nozzles.

3. A furnace firing equipment such as defined in claim 1, wherein the valve for controlling the admission of air to the housing is provided with a concave surface facing the housing air inlet for directing air smoothly towards the air inlet openings to the burner conduit and the air chamber.

a. A furnace firing equipment of a construction such as defined in claim 1, wherein the valve for controlling the inlet of air to the housing is pivotally mounted and is provided with a concave surface facing the housing air inlet and is further provided with a curved wall portion arranged in separated relation to the wall of the housing air inlet when the valve is closed, said curved wall portion being coaxial with the pivotal axis of the valve and acting in conjunction with the wall of the housing air inlet to prevent any appreciable increase in air delivery to the housing as the valve is opened until the valve is approximately completely opened.

5.'In a furnace firing equipment, a burner comprising a tubular conduit, a Venturi tube for discharging a mixture of primary air and fuel into said conduit, an air chamber surrounding said conduit, a plurality of air nozzles extending into said conduit at a point beyond the point of discharge of the Venturi tube and forming a communication between the air chamber and the interior of the conduit, secondary air inlets for said conduit communicating directly with the conduit, secondary air inlets for said conduit communicating with the conduit through the afore-mentioned air chamber and nozzles, means to control the admission of secondary air through said secondary air inlets which communicate with the air nozzles, an adjustable deflector in the discharge end of the conduit, and manually operable means for adjustably. positioning said deflector for controlling the point of ignition of the fuel and the length of the burner flame.

6. A furnace firing equipment for use with a furnace having a horizontally disposed tubular burner setting, a burner comprising a tubular conduit disposed within said setting and cooperating with said setting to form an air chamber surrounding said conduit, the inner end of said burner conduit having communication with the furnace through the inner end of the burner setting, the outer end of said conduit carrying a Venturi tube adapted to discharge a mixture of primary air and fuel into said burner conduit, secondary air inlets communicating with the conduit and with the air chamber surrounding the conduit, and air jets extending radially into the conduit at a point intermediate its ends and at a point beyond the discharge end of the Venturi tube and forming a communication between the interior of the conduit and the aforesaid air chamber, the parts operating as and for the purpose described.

7. A structure such as defined in claim 6, wherein there is an adjustable deflector within the discharge end of the burner conduit and manually operable means are provided for adjusting and-moving said deflector longitudinally of the conduit.

8. In a furnace firing equipment a tubular conduit, a Venturi tube for discharging a mixture of primary air and fuel into said conduit said Venturi tube being of a diameter considerably less than the diameter of the conduit and positioned with its axis coinciding with the longitudinal axis of the conduit, an air chamber surrounding the conduit, a plurality of air nozzles extending into the conduit between the discharge end of the Venturi tube and the discharge end of the conduit and forming a communication between the air chamber and the interior of the conduit, and means for controllably admitting secondary air to the air chamber, the parts operating as and for the purpose described.

9. A structure such as defined in claim 8, wherein additional means is provided for controllably admitting secondary air directly into the conduit independent of any passage of the air through the air chamber or nozzles and at points in the conduit in front of the nozzles.

10. In combination with a furnace having an opening in its front wall carrying a horizontally disposed tubular burner setting with open ends, a burner, said burner comprising a tubular conduit concentrically arranged within the tubular burner setting and having an open end adjacent the open inner end of the setting, an air chamber between the burner conduit and the tubular burner setting, nozzles extending into the burner conduit and forming a communication between the interior of said conduit and the air chamber, a housing surrounding that portion of the burner setting and the burner conduit which extends outwardly beyond the furnace face, a secondary air inlet for said housing, a valve for controlling the passage of air from said inlet to said housing, a valve controlled opening forming a communication between the burner conduit and the housing, a valve controlled opening forming a communication between the air chamber and the housing, the outer end of said burner conduit carrying a Venturi tube the inner end of which extends well into the burner conduit and is arranged with its axis coinciding with the longitudinal axis of the burner conduit, the parts operating for the purpose described.

WILLIAM ARMSTRONG WOODESON.

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