US2393897A

US2393897A - Burner

Info

Publication number: US2393897A
Application number: US529880A
Authority: US
Inventors: Glendenning Everett Burr
Original assignee: Shell Development Co
Current assignee: Shell Development Co
Priority date: 1944-04-05
Filing date: 1944-04-05
Publication date: 1946-01-29
Anticipated expiration: 1963-01-29
Also published as: ES177754A1

Description

Jan. 29, 1946. E. B. GLENDENNING 29393,897

BURNER Filed April 5, 1944 2 Sheets-Sheet 1 ooooo 4 Fig. 111

lnvQnTor-Z Ever-2T1 Burr Glendznninq Bq his Aflorne M Jan, 29, 1946. E. B. GLENDENNING 2,393,897

BURNER Filed April 5, 1944 2 Sheets-Sheet 2 lnvznTori Evzrerr Burr (ilrzndenninq 5% his H ZYA -Q Patented Jan. 29, 1946 UNITED ST TES PATENT OFFICE BURNER Everett Burr Glendenning, Cranford, N. 1., as-

signor to Shell Development Company, San Francisco, Calif., a corporation of Delaware Application April 5, 1944, Serial No. 529,880 1 Claims. (01. 158-76) The present invention relates to combustion burners adapted to burn fluid fuels, and more particularly to pressure atomization burners for use with liquid hydrocarbon fuels.

It has become common practice in many instances to employ liquid fuel burners for maritime. industrial and domestic heating purposes, these burners being largely automatic in operation and requiring a minimum of attention. One of the more commonly used types of liquid fuel burners is known as a "pressure jet burner and comprises an arrangement for atomizing fuel oil or other liquid fuel by supplying a stream of fuel under pressure to an atomizing nozzle and mixing the atomized fuel with converging air blasts in order to attain efficient combustion and derive the maximum heat values from the fuel. It is quite important in this type of burner to maintain optimum operating conditions, as even slight variations in the rate of feed or direction of flow path within the mixing zone will bring about inefficient combustion, as evidenced by excessive fuel consumption per B. t. u. of heat produced, a smoky flame resulting in carbon and/or soot deposition in the boiler or furnace etc. The optimum operating conditions of pressure jet burners may best be determined accurately by analysis of the combustion products, the quantity of carbon dioxide present indicating the efficiency of combustion. The operating variable which may be most easily adjusted to obtain the desired combustion efficiency is the air supply to the combustion chamber, the fuel generally being supplied to the atomizing nozzle at a constant rate and pressure by means of a pressure pump and regulator.

Since the operating conditions are critical, it has been found that a burner designed for emcient operation with a particular type of fuel is often unsatisfactory when a fuel having somewhat dissimilar properties is used. This is particularly true if an attempt is made to burn fuels containing appreciable quantities of aromatic components in a conventional pressure jet burner. It is an object of the present invention to provide an improved pressure jet combustion burner. A further object is to provide a pressure J'et combustion burner which is easily adjustable for efficient burning of various types of liquid fuels, both aromatic and non-aromatic in character. Another object is to provide a pressure jet combustion burner embodying positive and accurate air control to the combustion chamber over a wide range of operating conditions. Other objects, together with some of the advantage to be derived in utilizing the present invention, will become apparent from the following detailed description thereof, taken together with the accompanying drawings forming a part of the specification and wherein:

Figure I is a side elevation of the burner assembly;

Figure II is an enlarged side elevation partially in section with the air casing and fan removed;

Figure III is an enlarged sectional side elevation of the rear section of the burner;

' Figure IV is a rear elevation of the burner as shown in Figure III with the control cover removed;

Figure V is a section through V-V of Figure HI;

Figure VI is an enlarged sectional side elevation of the front end of the burner as shown in Figure II, the primary air housing being removed;

Figure VII is a section through VII-VII 0 Figure VI; j

Figure VIII is a section through VIIIVl1I of Figure VI.

Referring to Figure I, the burner comprises a conventional air casing l and motor driven fan assembly 2, including fan shutter adjusting lever 80, adapted to deliver air to air casing I. A primary air housing 3, cylindrical in shape, is rigidly mounted in the front of casing I and in turn rigidly supports a beveled outer deflector, element 1. Rear cover plate 8 is also rigidly attached to air casing I and in turn supports control cover 6 which is demountably attached thereto. A longitudinal slot 5, the purpose of which will be explained below, permits a flexible fuel supply conduit 4, to enter air casing I.

In Figure II, a spirally finned air rotator 9, having an annular form is rigidly positioned within primary air housing 3, near the discharge end thereof as shown. A secondary air housing 10, is supported at the front end by and slidably mounted in air rotator 9. The rear end of secondary air housing I'll is rigidly but detachably mounted on an annular projection 6|, formed as a part of cover plate element l 9. An annular series of air ports as at are provided to the rear of secondary air housing in in the annular projection 6|. An air control ring II is rotatably mounted upon the periphery of element l9 and is provided with an annular series of air ports as at I2, adapted to register with the ports 60 in annular projection GI when control ring H is in one position, and preventing air flow through air ports 60 when control ring H is rotated to a l1, which is in turn threaded to receive a conventional atomizing spray nozzle It. Support ele-. ment 20. is rigidly mounted on and supported by conduit l8. .A pair of starting electrodes comprising'conductors 2|, 23 and insulators 22, 24 (Figure VII) are. mounted in and rigidly supported by support element 29. These electrodes also pass through element l9 and terminate near the tip of atomizing nozzle l6, element l9 being slidable with respect to the electrodes. Adjustment rod 29 passes through and threadedly engages element l9 at 32. Rod 29 is enclosed within tube member 28 which passes through and is slidable within an opening provided in support element 20. A section of the inner flange of control ring I I isprovided with gear teeth at 25 which engage gear teeth provided on flange 26 which is formed as a part of bushing 52, which is fixedly mounted on the end of tube 28. A pair of bushings 21, 3|, areslidably mounted on tube 28 between support member 29 and'bushing 62, spring 30 normally urging bushings 21 and 3| apart.

Referring particularly to Figures VI and VIII, beveled, annular deflector element I3 is rigidly mounted in the end of secondary air housing l0. Spaced rearwardly from deflector element I3, a second deflector element l4 having a beveled annular form is also rigidly mounted in secondary air housing In and is provided with an annular series of air ports as at l5.

Deflector elements I and l3 define an annular air. discharge chamber which served as the primary air supply to the air-fuel mixing zone, deflector element I accordingly being considered to be the primary air nozzle. Similarly, secondary air is directed to the mixing zone by means of deflector plates l3 and I4 and these elements are considered to constitute the secondary air nozzle.

In Figures III, IV and V, the rear construction of the burner is shown. Casting element 35 is provided with a fuel conduit 35 which terminates in a threaded female joint at 65 to receive the threaded end of conduit l8. A threaded female joint at 55 is adapted to receive the flexible fuel supply conduit 4 (Figure I) The head of threaded bolt 45 is mounted in casting 35 and adapted to rotate freely therewithin. The threaded portion of bolt 45 passes through rear cover plate 8 in threaded engagement therewith at 44. Control knob 45 is fixedly attached to the end of bolt 45 and serves to rotate the same. A calibrated dial 61 is fixedly attached to control knob 45. A calibrated pin 41 is mounted in rear cover plate 8 immediately adjacent dial 91.

A bushing element 31 is fixedly mounted on the end of tube 28 and secured in position by means of set screw 38, the end of bushing 31 towards rear cover plate 8 terminating in a pair of rectangular keys 69 and III which engage grooves cut in tube 4| toform a spline joint adapted for longitudinal adjustment. Tube 4| passes through casting 35 and rear cover plate 8 and is rotatable within each of these. Longitudinal displacement of tube 4| with respect to casting 35 is prevented by. means of bushing 39 aflixed to tube 4| by means of set screw 40 and bushing 42 aflixed to tube 4| by means of set screw I5. Adjustment rod 29 passes through and is rotatable within tubes 28 and 4|. Control knob 43 including caliasoaaov brated dial H is rigidly attached to the end of rod 29 protruding beyond tube 4| and serves as a means for rotating rod 29.

Bushing 42 is provided with an arm 13, rod 5| being rigidly mounted at the outer end thereof and extending through arcuate slot 50 in rear cover plate 8. Control knob 49 is threadedly mounted on the end of rod 5| and retains spring 53 against rear cover plate 8. 7

In operating a pressure jet burner, the fuel is normally supplied at a constant rate and pressure to the atomizing nozzle, variations in air supply providing the necessary adjustments. In adjusting operating conditions of the burner to obtain maximum efliciency of combustion, according to the present invention, the following variables come into consideration;

1. The amount of air supplied to the burner.

2. The relative amounts of air supplied to the primary and secondary air nozzles.

3. The disposition of the atomizing nozzle with respect to the primary air nozzle.

4. The disposition of the atomizing nozzle with respect to the secondary air nozzle.

5. The disposition of the primary air nozzle with respect to the secondar air nonle.

The coaction of the various elements of the burner in bringing about the above adjustments in air supply are as follows:

The amount of air supplied to the burner is controlled in the conventional manner wherein the air intake to the motor driven fan is controlled by a variable shutter through an external control lever as that at 80,

Rotation of control knob alters the disposition of casting 35 with respect to rear cover plate 8 which is rigidly fixed through its mounting on air casing l. Thus, if control knob 45 is rotated to the left, threaded bolt 44 is withdrawn from rear cover plate 8 towards control cover 6. Casting 35, together with flexible fuel conduit 4 entering thru slot 5 in casing I, is accordingly moved longitudinally towards rear cover plate 8, carrying therewith conduit I8 including atomizing nozzle l5 as well as tubes 4| (which is slidable through rear cover plate 8) and 28 containing rod 29 which is attached to element l9 which in turn carries secondary air housing l8. Since primary air housing 3 is rigidly mounted in air casing l and secondary air housing "I is slidably supported by air rotator 9, it will be seen that knob 45 serves to simultaneousl modify the position of both the atomizing nozzle and the secondary air housing with respect to the primary air housing.

Manipulation 0! control knob 49 in arcuate slot 50 serves to bring about a partial rotation of bushing 42 through arm 13 and rod 5|. Since bushing 42 is fixedly attached to tube 4|, a corresponding rotation of tube 4| takes place and in turn, through the spline joint, a corresponding rotation of tube 28. Bushing 32 including flange 28 being fixedly attached to tube 28, a corresponding motion is transmitted to gear 25 resulting in rotation of air control ring II, with consequent variation in the degree of registration between air ports and I2. These ports serve as the primary flow communication means between the interior of primary air housing 3 and secondary air housing In. It will thus be seen that control knob 49 serves to control the relative amounts of air supplied to the primary and secondary air nozzles.

Spring 53 (Figure V) serves as a friction element, bearing against rear cover plate 8 and conat 32, Element l9 being free to slide upon conduit i8 and secondary air housing Ill being mounted on element IS, a corresponding longitudinal movement of the secondary air nozzle with respect to atomizing nozzle l8 takes place.

Likewise, secondary air housing l0 being free to slide in air rotator 9, a longitudinal adjustment of the position of secondary air housing In with respect to primary air housing 3 occurs. The displacement of tube 28 which also takes place in making this adjustment is taken up in the spline joint, thus requiring no corresponding movement of tube 4|. Spring serves to apply a constant pressure, through support element 20 which is rigidly mounted on conduit Hi, to the back of element l9, thus providing suiilcient friction in the threaded engagement between rod 29 and element l9 at 32 to maintain the position to which the adjustment is manually set.

The following is the preferred procedure in starting operation of the burner. An atomizing nozzle of desired size and spray angle is selected and installed at the discharge end of fuel conduit l8, and the unit assembled as shown in Figure I. The secondary air nozzle is then adjusted to its rearward position by means of control knob 13. The action places the secondary air nozzle in its rearward position with respect to the atomizing nozzle. The fan shutter is set to an approximately three-quarters open position.

Control knob 45 is then adjusted to bring the atomizing nozzle to a position approximately midway in its adjustment range with respect to the primary air nozzle. Control knob 49 is adjusted to permit maximum air supply to secondary air housing I 0 through air ports I 2 and 60.

After the above adjustments have been made, fuel and air are supplied to the burner and the fuel ignited by means of the spark igniters. Fuel is supplied to the atomizing nozzle at a constant pressure, usually approximately 100 p. s. i., in order to insure a constant fuel flow through the nozzle and uniform atomization. If it appears by visual observation of the flame that the fan is supplying an excess of air for efficient combustion of the quantity of fuel being supplied to the combustion zone, control knob 45 is adjusted to move secondary air housing In and atomizing nozzle it forward until the flame starts to smoke slightly, due to reduction in the supply of primary air as the front of the secondary air nozzle approaches deflector plate I of the primary air nozzle. The secondar air housing is then moved slightly backwards until the smoking is eliminated. The combustion eiliciency is then determined by analysis of the flue gases by means of Orsat apparatus or the like whereby the carbon dioxide content of the flue gases may be ascertained. If the carbon dioxide content is not sufficiently high, the fan shutter is closed slightly by means of lever 80 to reduce the static pressure within primary air housing 3 and the combustion efilciency again checked by visual inspection and flue gas analysis. When no further intrease in the carbon dioxide content of the flue gases can be obtained by adjustment of the fan shutter and control knob 45, the flow of air to the secondary air housing is decreased by adjustment of control knob 49. When the maximum carbon dioxide content has been obtained with this adjustment, which permits the flame to burn closer to atomizing nozzle l6, control knob 43 is adjusted until the ultimate maximum combustion efficiency is obtained, as determined by the carbon dioxide content of the flue cases.

It has been found that when using relatively small capacity fuel nozzles, it is preferable to operate with the secondary air nozzle well back from the face of the fuel nozzle, whereas with relatively large capacity fuel nozzles, the secondary air nozzle may be moved forward with advantage.

I claim:

1. In a burner the combination comprising a primary air housing, an air casing in flow communication with said primary air housing rigidly attached to and extending rearwardly from said primary air housing, means for supplying air to said air casing, a rear cover plate closing said air casing, a primary air nozzle mounted on the discharge end of said primary air housing, a secondary air housing within said primary air housing and defining an annular space between said primary air housing and said secondary air housing, a cover plate closing the rear end of said sec-' ondary air housing, a secondary air nozzle mounted on the discharge end of said secondary air housing, means rigidly positioned in the forward section of said primary air housing supporting said secondary air housing near the discharge end thereof, said secondary air housing being in slidable contact with said supporting means, a fuel nozzle within said secondary air housing and defining an annular space between said secondary air housing and said fuel nozzle, conduit means in flow communication with said fuel nozzle passing through said secondary air housing cover plate in slidable relationship therewith, means for supplying fuel to said conduit means, adjustable flow communication means between said primary air housing and said secondary air housing, and means engaging said secondary air housing cover plate and extending rearwardly through the cover plate closing the air casing, said means being adapted to vary the longitudinal displacement of said secondary air housing with respect to said primary air housing and said fuel nozzle.

2. In a burner the combination comprising a primary air housing, an air casing in flow communication with said primary air housing rigidly attached to and extending rearwardly from said primary air housing, means for supplying air to said air casing, a rear cover plate closing said air casing, a primary air nozzle mounted on the discharge end of said primary air housing, a secondary air housing within said primary air housing and defining an annular space between said primary air housing and said secondary air housing, a plate closing the rear end of said secondary air housing, a secondary air nozzle mounted on the discharge end of said secondary air housing, means rigidly positioned in the forward section of said primary air housing supporting said secondary air housing near the discharge end thereof, said secondary air housing being in slidable contact with said supporting means, a fuel nozzle within said secondary air housing and defining an annular space between said secondary air housing and said fuel nozzle, conduit means in flow commuication with said fuel nozzle passing through said secondary air housing cover plate in slidable relationship therewith, means for supplying fuel to said conduit means, adjustable flow communication means between said primary air housing and said secondary air housing, and means engaging said fuel conduit means and extending rearwardly through the cover plate closing the air casing, said engaging means being adapted to vary the longitudinal displacement of said fuel nozzle and said secondary air housin with respect to said primary air housing.

3. In a burner the combination comprising a primary air housing, an air casing in flow communication with said primary air housing rigidly attached to and extending rearwardly from said primary air housing, means for supplying air to said air casing, a rear cover plate closing said air casing, a primary air nozzle mounted on the discharge end of said primary air housing, a secondary air housing within said primary air housing and defining an annular space between said rimary air housing and said secondary air housing, a cover plate closing the rear end of said secondary air housing, a secondary air nozzle mounted on the discharge end of said secondary air housing, means rigidily positioned in the forward section of said primary air housing supporting said secondary air housing near the discharge end thereof, said secondary air housing being in slidable contact with said supporting means, a fuel nozzle within said secondary air housing and defining an annular space between said secondary air housing and said fuel nozzle, conduit means in flow communication with said fuel nozzle passing through said secondary air housing cover plate in slidable relationship therewith, means for supplying fuel to said conduit means, adjustable flow communication means between said primary air housing and said secondary air housing, means engaging said secondary air housing cover plate adapted to vary the longitudinal displacement of said secondary air housing with respect to said primary air housing and said fuel nozzle, and means engaging said conduit means adapted to vary the longitudinal displacement of said fuel nozzle and said secondary air housing with I'Ba spect to said primary air housing, both of said last-mentioned engaging means extending rearwardly through the cover plate closing the air casin 4. In a burner the combination comprising a primary air housing, an air casing in flow communication with said primary air housing rigidily attached to and extending rearwardly from said primary air housing, a rear cover plate closing said air casing, a primary air nozzle mounted on the discharge end of said primary air housing, a secondary air housing annularly perforated towards the rear end thereof within said primary air housing and defining an annular space between said primary air housing and said secondary air housing, a cover plate closing the rear end of said secondary air housing, a secondary air nozzle mounted on the discharge end of said secondary air housing, means rigidly mounted in said primary air housing and near its discharge end, said means supporting said secondary air housing near the discharge end" thereof, said secondary air housing being in slidable contact with said supporting means, a fuel nozzle within said secondary air housing and defining an annular space between said secondary air housing and said fuel nozzle, conduit means in flow communication with and supporting said fuel nozzle passing through said secondary air housing cover plate in slidable relationship therewith, means for supplying fuel to said conduit means, means for supplying air to said air casing, an annularly perforated ring rotatably mounted on said secondary air housing, the perforations in said ring being adapted to coincide with the annular perforations in said housing, an actuable gear element adapted to rotate said annular ring and thereby vary the degree of alignment of said perforations in said secondary'air housing and said annular ring, an actuating gear meshing with said actuable gear, a tubular operating element rigidly attached to said actuating gear and extending through said rear cover plate of said air casing, and a shaft threadedly engaging said cover plate of said secondary air housing extending through said tubular operating element and rotatable therewithin to vary the longitudinal displacement of said secondary air housing with respect to said fuel nozzle and said primaryair housing.

5. In a burner the combination comprising a primary air housing, an air casing in flow communication with said primary air housing rigidly attached to and extending rearwardly from said primary air housing, a rear cover plate closin said air casing, a primary air nozzle mounted on the discharge end of said primary air housing, a secondary air housing annularly perforated towards the rear end thereof within said primary air housing and defining an annular space between said primary air housing and said secondary air housing, a cover plate closing the rear end of said secondary air housing, a secondary air nozzle mounted on the discharge end of said secondary air housing, means rigidly mounted in said primary air housing and near its discharge end, said means supporting said secondary air housing near the discharge end thereof, said seconary air housing being in slidable contact with said supporting means, a fuel nozzle within said secondary air housing and defining an annular space between said secondary air housing and said fuel nozzle, conduit means in flow communication with and supporting said fuel nozzle passing through said secondary air housing cover plate in slidable relationship therewith, means for supplying fuel to said conduit means, means for supplying air to said air casing, an azmularly perforated ring rotatably mounted on said secondary air housing, the perforations in said ring being adapted to coincide with the annular perforations in said housing, an actuable gear element adapted to rotate said annular ring and thereby vary the degree of alignment of said perforations in said secondary air housing and said annular ring, an actuating gear meshing with said actuable gear, a tubular operating element rigidly attached to said actuating gear and extending through said rear cover plate of said air casing, and a shaft threadedly engaging said cover plate of said secondary air housing extending through said tubular operating element and rotatable therewithin to vary the longitudinal displacement of said secondary air housing with respect to said fuel nozzle and said primary air housing, and means engaging said conduit means threadedly engaging said rear cover plate of said air casing adapted to simultaneously vary the longitudinal displacement of said secondary air housing and said fuel nozzle with respect to said primary air housing.

6. In a burner the combination comprising a closed primary air housing open at its discharge asoaaer end, a secondary air housing, open at its discharge end, contained and longitudinally adjustable within said primary housing and defining an annular passageway therewith, a fuel nozzle within said secondary air housing and longitudinally adjustable with respect thereto, means engaging said secondary air housing and extending through and outside the primary air housing for adjusting the longitudinal position of the secondary air housing with respect to the primary air housing and the fuel nozzle, air rotator means within the primary air housing in slidahle contact with the secondary air housing, means for supplying air to the primary air housing, and an air passage in the said secondary air housing for admitting air from the primary air housing to the secondary air housing.

7. In a burner the combination comprising a closed primary air housing open at its discharge end, a secondary air housing, open at its discharge end, contained and longitudinally adjustable within said primary housing and-defining an annular passageway therewith, a fuel nozzle within said secondary air housing and longitudinally adjustable with respect thereto, means engaging said secondary air housing and extending through and outside the primary air housing for adjusting the longitudinal position of the secondary air housing with respect to the primary air housing and the fuel-nozzle. air rotator means within the primary air housing in slidable contact with the secondary air housing, said means traversing substantially the entire cross section of the said annular passageway, means for supplying air to the primary air housing, and an adjustable air passage in the said secondary air housing for admitting air from the primary air housing to the secondary air housing.

EVERETT BURR GLENDENNING.