US3233605A - Apparatus for heating asphaltic pavement - Google Patents

Description

Feb. 8, 1966 F. F. MOENCH 3,233,605

APPARATUS FOR HEATING ASPHALTIG PAVEMENT Filed Aug. 12, 1963 3 Sheets-Sheet 1 INVENTOR. Frank E Moench ATTORNEYS Feb. 8, 1966 F. F. MOENCH APPARATUS FOR HEATING ASPHALTIC PAVEMENT 3 Sheets-Sheet 2 Filed Aug. 12, 1963 INVENTOR. Frank Ff Moench ATTORNEYS Feb. 8, 1966 F. F. MOENCH APPARATUS FOR HEATING ASPHALTIC PAVEMENT 3 Sheets-Sheet 5 Filed Aug. 12, 1963 INVENTOR. Frank F. Moench BY ATTORNEYS United States Patent 3,233,605 APPARATUS FOR HEATING ASPHALTIC ?AVEMENT Frank F. Moench, 4214 E. Colfax Ave, Denver 20, Colo. Filed Aug. 12, 15963, Ser. No. 3L5tl8 6 (Jlaims. (Cl. 126-2713) This invention relates to apparatus for smoothing asphaltic paving and more particularly relates to apparatus for smoothing roughened surfaces of asphalt or blacktop paving.

Asphalt or blacktop surfaces are widely used as highway surfaces and in parking areas, etc., where large areas have to be covered with an all'weathcr, hardtop surface over which automobiles and other heavy vehicles and loads are moved and which is resistant to prevailing temperature and atmospheric effects. In the course of such usage, irregularities develop, particularly corrugated or undulating surfaces, which become a hazard to the normal uses of such areas and are developed or increased by continuing usage.

Such pavement is formed in the first instance by hot application and, while hot, is shaped to form a relatively flat surface. After forming, it is allowed to cool and harden so that it provides a relatively-permanent, hard surface over which vehicles travel. Unfortunately, soft spots in the base structure supporting the pavement dc veiop, and repeated bumping of heavy vehicles over such soft spots increases the undulating or corrugated effect to such an extent that such surfaces become a traflic hazard by inducing erratic vehicular movement over same with resulting increase in the intensity of the undulating or washboard effect.

The present invention recognizes the need to recondition such undulating or corrugated surfaces without rebuilding the entire top surface, and provides a simple, economical and efficient procedure by which such irregular surfaces may be flattened and smoothed through a combination of heating and softening followed by smoothing such as by scraping.

Such treatments may be produced by one treatment unit which provides the heating and softening and a second unit which provides the necessary scraping or smoothing. An operation of this type requires plural operator control, plural vehicular movement, and the possibility of erratic timing causing an unwanted interval of inactivity between heating and smoothing. As a consequence, such operations are usually expensive and frequently inefficient.

Accordingly, it is an object of my invention to provide simple, durable and etiicient apparatus adapted to be mounted on existing road-working equipment which provides a combined heating or softening action and a smoothing or scraping action for improving defective surfaces.

Another object of my invention is to provide simple, economical and efficient apparatus for treating asphaltic or hardtop pavement so as to eliminate roughened or corrugated portions thereof.

Other objects reside in novel details of construction and novel combinations and arrangements of parts, all of which will be described in the course of the following description.

My invention will be described with reference to the accompanying drawings, in the several views of which like parts bear similar reference numerals. In the drawings:

FIG. 1 is a side elevation of a road grader on which the apparatus of my invention has been mounted;

FIG. 2 is a fragmentary top plan view of the fuel circulating system of the apparatus installed on the road scraper shown in FIG. 1;

FIG. 3 is a top plan View of the combustion chamber and burner assembly of the apparatus shown in FIG. 1;

MG. 4 is a fragmentary section taken along the lines 4-4, FIG. 3, and drawn to an enlarged scale;

FIG. 5 is a section taken along the lines 55, FIG. 4, and drawn to an enlarged scale;

FIG. 6 is a fragmentary side elevation, partially in section, of the burner mounting arrangement in an assembly of the type shown in FIG. 3; and

FIG. 7 is an isometric drawing of one of the liner members of the type shown in FIG. 4.

FIG. 1 represents a typical arrangement in which the novel apparatus is mounted on road-working equipment of any standard type having a scraper blade adjustable to different contact positions. As shown, the road grader 11 has an elongated frame, supporting an operators cab 12 and power unit 13 mounted at its rear over the drive wheel assembly 14. The forward end of the frame is supported by wheels 15 controlled from cab 12 by a steering wheel 16 for steering and maneuvering the grader vehicle. The grader blade or moldboard 17 is disposed under an elevated portion of the vehicle frame between the front and rear wheels, usually in a position to be observed by the vehicle operator while operating.

The vehicle 11 has a hydraulic power system and a hydraulic drive unit 13 is connected at 19 with a hinged beam 2% on which the moldboard 17 is carried, permitting it to be tilted laterally and raised or lowered so that the blade can be disposed in selective cutting positions by control of the operator in cab 12.. The apparatus of my invention includes a novel combustion chamber and burner assembly 21 which is mounted in a suspended position under the forward end of the frame in advance of moldboard 1'7 for selectively heating and softening portions of the pavement in the line of advance of the moldboard. The features of the mounting and controls of the combustion chamber assembly will be set forth in detail in the following description.

The aforesaid arrangement permits the operator of the vehicle 11 to selectively heat and soften roughened areas of the pavement preparatory to cutting and removing elevated surfaces by the following movement of the moldboard. The positioning of the assembly 21 provides a draft control interiorly of the assembly with ample oxygen supplied to support combustion and air flow directed to avoid impedance or interference with heat direction. In ordinary operation, there is no direct flame on the asphalt, and burner temperatures on the order of 2400 F. are developed with the heat energy radiated by the liners to penetrate the pavement with a major portion of the heat input in the infra red region of the spectrum.

A low pressure gas is utilized as the fuel supply to the combustion chamber 22, and a supply tank 23 is mounted at the rear of vehicle for delivery through a conduit system inclucing control members 26 located in the cab 12, and a header or manifold in the burner assembly 24 supplied by a line 25 extending from the control station 26 in cab 12. A pair of beams 27 fixed on the vehicle frame has a hinged connection 28 with the top of combustion chamber 22; at opposite sides of its center line and extensible rods or hangers 30 have hinged connections 29 with the forward end of the combustion chamber assembly and such connections preferably include a coil spring as shown.

Another hydraulic power unit 31 is connected with beams 27 for raising or lowering same under operator control as shown at 32 and additional adjustment is provided by manually extending or retracting connections 29 to predetermined positions of inclination whereby the forward end of the combustion chamber is maintained in spaced but proximate relation to the pavement surface,

, while its rear end is disposed at a higher elevation to provide the desired draft control and insure intake of an adequate air supply to support combustion. A heat shield 33 is suspended forwardly of the combustion chamber to prevent overheating of the front tires. in a typical installation the forward end will have about 1 clearance whereas the rear end will have from 4 to 6 clearance.

As shown in FIG. 3, the manifold 37 supplied by line is carried on a framework of channel members, in cluding side members L la which are bolted or otherwise attached to the sides of the combustion chamber 22 at its rear, and an integral end or bridging member 34b along which manifold 37 extends. An intermediate support member 34c stabilizes the framework support on the combustion chamber. The members 34a and 340 are fastened or held in a normally horizontal position as shown, but may be rotated about bolts 35a as pivots and relocating associated bolts 35!) in openings provided so as to dispose the plurality of burner units 36 carried on bridging member 3411 in a substantially vertical or downward direction.

This latter adjustment is provided for direct flame application to the pavement surface as when the mat contains too much oil and also in snow or ice removal operations. For such oil removal, the high heat condition of the combustion chamber operation is not required and the vehicle is moved at a higher speed to control the amount of burning. If desired, the combustion chamber may be raised by the power unit 31 to provide maximum clearance over the surface being heated.

One of the features of the combustion chamber assembly is that the liners are mounted as an integral cover for the entire inside of the combustion chamber shell or housing and the joints are sealed to eliminate gaps which would function as heat paths and damage the housing by excessive temperatures. The shell or housing 39 is a box-like member open at its bottom and provided at its rear with a plurality of openings 40 which comprise the ports through which the fuel discharge from the burn ers is directed.

The liners 41 as shown in H6. 7 are formed in oblong locks having alined grooves 42 on the four sides. They are formed of refractory material capable of withstanding high temperatures without warping or shrinkage and as shown in FIG. 4 the grooves 42 of adjoining liners are positioned to form a recess A plurality of fasteners 44 are embedded in the ceramic material before it is fired and have fiat end portions 44a in the face of the block and hook portions 44b of the opposite end which are embedded in the block. As shown in FlG. 5, the flat ends 44a are welded to abutting ends of a backing portion of the housing 39 forming a strong rigid assembly. The recesses are filled with a glazing composition of the aluminum silicate type, such as the product of Carborundurn Corporation sold under the trademark Fibre-frail. While the grooves 42 abut surfaces of the housing, such as shown at the bottom of PEG. 4, such spaces also will be filled as described above.

The liner members 41 may be of any suitable composition capable of withstanding the high temperatures produced in the combustion chamber. A material of the type used in the lining of smelting furnaces is well suited for this purpose. However, under some conditions it may be preferable to utilize metallic alloys capable of withstanding the high temperatures produced.

In the ordinary operation of the combustion chamber, fuel will be delivered at from 40-65 pounds pressure after a preheating period in which the coils of the nozzle members are heated sufliciently to convert all the liquid fuel supply to gaseous state. As there are many situations in the use of such equipment where the full heat input is not required on a continuous basis, I have provide a pilot operation for the burners which may be conveniently substituted for the full fuel supply as in the case of lunch hour stops, movement of the vehicle from one operating location to another and the like. This ard rangement is shown in FIG. 2 and the controls for the bypass circuiting will be located at station 26 in cab 12.

In the arrangement shown in FIG. 2, the main fuel supply from tank 23 is conducted through a line 25 arranged vvith a main flow portion 25a connected to a bypass conduit 2%. The flow through portion 25a is under control of a regulating valve 45 at station 26 and whenever valve 45 is closed, flow is diverted through the bypass portion 25.). A needle valve 46 in the bypass line 25b permits volume control of the flow which usually is set for between 4 and 5 pounds pressure. A pressure regulator 47 is located downstream from valve 46 and a flutter valve 48 is located in line 25b downstream from the pressure regulator. Valve 48 permits fuel flow only in the downstream direction and opens under the pressure established by valve 46 to permit the flow to enter line 25 at the junction point 49. In the event that back pressure develops into line 25b, valve 48 will close and remain in such position until the pressure delivered through line 46 overcomes the back pressure and directs fuel flow downstream in its regular pattern. Valve 43 also functions to prevent back pressure flow through line 25b when valve 45 is open and the direct flow is passing through portion 25a. A pressure regulator Sil is located in portion 25a and a pressure indicator instrument 53 also is provided for location at station 26 for observation by the operator in cab 12.

At the beginning of a period of operation, the valve 45 is closed and valve 46 is set to provide the desired pressure in the flow through bypass line 25b. The burner discharge is ignited in any well known manner and the interior of the combustion chamber and the coil portion of the burner nozzles are heated progressively until the temperature is high enough to convert the liquid fuel discharge to a gaseous state. At that time, valve 45 is opened, cutting off the flow through bypass line 25b and the full heating effect is produced in combustion chamber 22;. This heating is fast enough so that the combustion chamber is ready for regular operation within about 10-15 minutes, bringing the temperatures on the inner face of the liners to approximately 2l00 F. If desired, the operator can adjust the positioning of the nozzles to provide more heat toward the rear of the combustion chamber and then gradually change the positioning to advance the maximum heating effect to the forward end of the chamber. When the heat has reached the operating requirement the vehicle is moved at a slow speed, usually 0.4-0 mph. or less and the heating of the pavement in such action softens the roughened surfaces suflicientiy so that they are readily removed by the scraping or cutting contact of the blades 17.

In some operations at the completion of the given stretch of forward movement, the vehicle will be hacked to make another pass over the treated area and as excessive heating may be undesirable in such movement, the fuel input can he cut off by directing the fuel flow through the bypass line 25b until the rearmost position is reached and the vehicle is ready to resume its forward movement. At that time, the valves will be operated again to provide maximum heat input to the combustion chamber.

During the course of any such heating actions, the operator is in a position to observe the action of the heating from his position in the cab 12 and if any flameout from the enclosure occurs, it indicates a supply of too much fuel and he makes the necessary cutback in the fuel delivered so as to maintain an optimum heating condition.

As the apparatus of the present invention is designed for installation on existing road working equipment, I have found it convenient to utilize the power system of such equipment for the various mechanical movements required in the operation and positioning of the apparatus. in the preceding description, reference has been made to the hydraulic system of the vehicle and the hydraulic power sources utilized in adjusting the combustion chamberrposition, etc. It will be understood that some road working equipment utilizes mechanical drives or power sources rather than hydraulic and mechanical drives will be quite satisfactory in the positioning of the combustion chamber and the like.

Inasmuch as the liner assembly of the combustion chamber requires infrequent replacement during the life of the apparatus, the arrangement of the header and nozzle mounting, together with the fastening of the liner members, permits a relatively simple and easy relining procedure. The fuel supply and burner assembly are easily demounted by a few simple operations and the entire combustion chamber can be moved to a position in which its interior is exposed for removal of worn liner sections and installation of a new liner assembly.

The adjustment of the burner position in the combustion chamber has been mentioned in the preceding description. As shown in FIGS. 4 and 6, fuel delivered through manifold 37 discharges into a branch line supplying each of the burners 36 and the branch line has a swivel joint 55 which permits manual tilting of the burner unit so that the flame may be directed against selective areas within the combustion chamber enclosure.

While any suitable fuel may be used, I prefer propane, although under some circumstances, butane may be used.

As shown in FIG, 5, provision is made for mounting the shed or housing 39 and associated liner assembly onsupporting structure by nut and blot assemblies 56. Forexample, the burner assembly 22 shown in FIG. 3 is connected to a pair of beams 57 by the assemblies 56 and said beams comprise the structure on which the member 27 is hinged and to which the hangers 30 are attached.

Changes and modifications may'be availed of within the spirit and scope of the invention as set forth in the hereunto appended claims.

I claim:

1. A combustion device including a combustion chamber for transport on a vehicle in overhanging relation to a supporting surface to be heated, said combustion chamber comprising a box-like housing having an open bottom and closed on its sides and top, a plurality of four-sided heat-radiating members of refractory material in abutting relationship lining the interior of the tops and sides of said housing and being of sufficient thickness to heatinsulate the exterior walls of the housing, each said member having a smooth outer surface portion separately attached and rigidly secured to a backing portion of the inner Walls of the housing and having an alined grooved portion in each of its four sides forming cup-like portions between facing grooves, a glazing composition of the aluminum silicate type filling said cup-like portions and the space between said adjoining liner members to close the air space and to prevent heat transmission therebetween thereby providing a substantially continuous lining within the housing, said composition retaining its generally plastic condition after continued periods of usage, a header at the rear end of the housing connected with a fuel supply of low pressure gas in conductive connection with a plurality of horizontally-directed burner nozzles disposed adjacent the top of the chamber and constructed and arranged to confine flame propagation in contact with the inner lining, said lining receiving the heat so generated and radiating heat in the infra-red region of the spectrum toward the open underside so as to heat the portion of the supporting surface over which the housing is disposed, and means for selectively varying the fuel delivered to said nozzles.

2. A combustion device including a combustion chamber for transport on a vehicle in overhanging relation to a supporting surface to be heated, said combustion chamber comprising a box-like housing having an open bottom and closed on its sides and top, a plurality of four-sided heat-radiating members of refractory material in abutting relationship lining the interior of the tops and sides of said housing and being of sufficient thickness to heat- 6 insulate the exterior walls of the housing, each said member having a smooth outer surface portion separately attached and rigidly secured to a backing portion of the inner walls of the housing and having an alined grooved portion in each of its four sides, forming cup-like portions between facing grooves, a glazing composition of the aluminum silicate type filling said cup-like portions and the space between said adjoining liner members to close the air space and to prevent heat transmission therebetween thereby providing a substantially continuous lining within the housing, said composition retaining its generally plastic condition after continued periods of usage, a header at the rear end of the housing connected with a fuel supply of low pressure gas delivered at a r pressure of from about 4-0 to 65 pounds and in conductive connection with a plurality of horizontally-directed burner nozzles disposed adjacent the top of the chamber and constructed and arranged to confine flame propagation in contact with the inner lining, said lining receiving the heat so generated and radiating heat in the infra-red region of the spectrum toward the open underside so as to heat the portion of the supporting surface over which the housing is disposed, and means for selectively varying the fuel delivered to said nozzles.

3. A combustion device including a combustion chamber for transport on a vehicle in overhanging relation to a supporting surface to be heated, said combustion chamber comprising a box-like housing having an open bottom and closed on its sides and top, a plurality of four-sided heat-radiating members of refractory material in abutting relationship lining the interior of the tops and sides of said housing and being of sufficient thickness to heatinsulate the exterior Walls of the housing, each said memer having a smooth outer surface portion with at least one hook-like fastener embedded in said member having a flat head portion separately attached and rigidly secured to a backing portion of the inner walls of the housing and having an alined grooved portion in each of its four sides forming cup-like portions between facing grooves, a glazing composition of the aluminum silicate type filling said cup-like portions and the space between said adjoining liner members to close the air space and to prevent heat transmission therebetween thereby providing a substantially continuous lining Within the housing, said composition retaining its generally plastic condition after continued periods of usage, a header at the rear end of the housing connected with a fuel supply of low pressure gas in conductive connection with a plurality of horizontally-directed burner nozzles disposed adjacent the top of the chamber and constructed and arranged to confine flame propagation in contact with the inner lining, said lining receiving the heat so generated and radiating heat in the infra-red regionof the spectrum toward the open underside so as to heat the portion of the supporting surface over which the housing is disposed, and means for selectively varying the fuel delivered to said nozzles.

4. A combustion device including a combustion chamber for transport on a vehicle in overhanging relation to a supporting surface to be heated, said combustion chamber comprising a box-like housing having an open bottom and closed on its sides and top, a plurality of four-sided heat-radiating members of a ceramic material in abutting relationship lining the interior of the tops and sides of said housing and being of sufiicient thickness to heatinsulate the exterior Walls of the housing, each said memher having a smooth outer surface portion separately attached and rigidly secured to a backing portion of the inner walls of the housing and having an alined grooved portion in each of its four sides, forming cup-iike portions between facing grooves, a glazing composition of the aluminum silicate type filling said cup-like portions and the space between said adjoining liner members to close the air space and to prevent heat transmission therebetween, thereby providing a substantially continuous lining within the housing, said composition retaining its generally plastic condition after continued periods of usage. a header at the rear end of the housing connected with a fuel supply of low pressure gas in conductive connection with a plurality of horizontally-directed burner nozzles dispose-d adjacent the top of the chamber and constructed and arranged to confine flame propagation in contact with the inner lining, said lining receiving the heat so generated and radiating heat in the infra-red region of the spectrum toward the open underside so as to heat the portion of the supporting surface over which the housing is disposed, and means for selectively varying the fuel delivered to said nozzles.

5. A combustion device including a combustion chamber for transport on a vehicle in overhanging relation to a supporting surface to be heated, said combustion chamber comprising a box-like housing having an open bottom and closed on its sides and top, a plurality of four-sided heat-radiating members of refractory material in abutting relationship lining the interior of the tops and sides of said housing and being of sufficient thickness to heatinsulate the exterior Walls of the housing, each said member having a smooth outer surface portion separately attached and rigidly secured to a backing portion of the inner walls of the housing and having an alined grooved portion in each of its four sides forming cup-like portions between facing grooves, a glazing composition of the aluminum silicate type filling said cuplil-2e portions and the space between said adjoining liner members to close the air space and to prevent heat transmission there between thereby providing a substantially continuous lining within the housing, said composition retaining its generally plastic condition after continued periods of usage, a header at the rear end of the housing connected with a fuel supply of low pressure gas in conductive connection with a plurality of horizontally-directed burner nozzles operating at a temperature of about 2400" Fahrenheit disposed adjacent the top of the chamber and constructed and arranged to confine flame propagation contact with the inner lining, said lining receiving the heat so generated and radiating heat in the infra-red region of the spectrum toward the open underside so as to heat the portion of the supporting surface over which the housing is disposed, and means for selectively varying the fuel delivered to said nozzles.

6. A combustion device including a combustion chamher for transport on a vehicle in overhanging relation to a supporting surface to be heated, said combustion cham- Q Q. ber comprising a box-like housing having an open bottom and closed on its sides and top, a plurality of four-sided heat-radiating members of refractory material in abutting relationship lining the interior of the tops and sides of said housing and being of sutficient thickness to heatinsulate the exterior walls of the housing, each said memher having a smooth outer surface portion separately attached and rigidly secured to a backing portion of the inner walls of the housing and having an alined grooved portion in each of its four sides forming cup-like portions between facing grooves, a glazing composition of the aluminum silicate type filling said cup-like portions and the space between said adjoining liner member to close the air space and to prevent heat transmission therebctween thereby providing a substantially continuous lining within the housing, said composition retaining its generally plastic condition after continued periods of usage, a header at the rear end of the housing connected with a fuel supply of low pressure gas in conductive connection with a plurality of horizontally-directed burner nozzles disposed adjacent the top of the chamber and constructed and arranged to confine flame propagation contact with the inner lining, said lining receiving the heat so generated and radiating heat in the infra-red region of the spectrum toward the open underside so as to heat the portion of the supporting surface over which the housing is disposed, and a fuel control for regulating the fuel supplied to said nozzles including a main conduit for passing fuel during the Working stage and a by-pass conduit for passing lesser fuel during the start-up and idling stages.

References Cited by the Examiner UNITED STATES PATENTS 1,712,629 5/1929 Moore l2627l.2 2,190,175 2/1940 Roche l2627l.2 2,223,283 l1/140 Grant et al 236-1 2,273,254 2/1942 Davis l2627l.2 3,063,442 11/1962 Brown 126--271.2 2,096,696 7/1963 Reisser 126-2712 FOREIGN PATENTS 756,083 8/1956 Great Britain. 867,862 5/1961 Great Britain.

FREDERICK L. MATTESON, IR., Primary Examiner.

JAMES W WESTHAVER, Examiner.

Claims (1)

1. A COMBUSTION DEVICE INCLUDING A COMBUSTION CHAMBER FOR TRANSPORT ON A VEHICLE IN OVERHANGING RELATION TO A SUPPORTING SURFACE TO BE HEATED, SAID COMBUSTION CHAMBER COMPRISING A BOX-LIKE HOUSING HAVING AN OPEN BOTTOM AND CLOSED ON ITS SIDES AND TOP, A PLURALITY OF FOUR-SIDED HEAT-RADIATING MEMBERS OF REFRACTORY MATERIAL IN ABUTTING RELATIONSHIP LINING THE INTERIOR OF THE TOPS AND SIDES OF SAID HOUSING AND BEING OF SUFFICIENT THICKNESS TO HEATINSULATE THE EXTERIOR WALLS OF THE HOUSING, EACH SAID MEMBER HAVING A SMOOTH OUTER SURFACE PORTION SEPARATELY ATTACHED AND RIGIDLY SECURED TO A BACKING PORTION OF THE INNER WALLS OF THE HOUSING AND HAVING AN ALINED GROOVED PORTION IN EACH OF ITS FOUR SIDES FORMING CUP-LIKE PORTIONS BETWEEN FACING GROOVES, A GLAZING COMPOSITION OF THE ALUMINUM SILICATE TYPE FILLING SAID CUP-LIKE PORTIONS AND THE SPACE BETWEEN SAID ADJOINING LINER MEMBERS TO CLOSE THE AIR SPACE AND TO PREVENT HEAT TRANSMISSION THEREBETWEEN THEREBY PROVIDING A SUBSTANTIALLY CONTINUOUS LINING WITHIN THE HOUSING, SAID COMPOSITION RETAINING ITS GENERALLY PLASTIC CONDITION AFTER CONTINUED PERIODS OF USAGE, A HEADER AT THE REAR END OF THE HOUSING CONNECTED WITH A FUEL SUPPLY OF LOW PRESSURE GAS IN CONDUCTIVE CONNECTION WITH A PLURALITY OF HORIZONTALLY-DIRECTED BURNER NOZZLES DISPOSED ADJACENT THE TOP OF THE CHAMBER AND CONSTRUCTED AND ARRANGED TO CONFINE FLAME PROPAGATION IN CONTACT WITH THE INNER LINING, SAID LINING RECEIVING THE HEAT SO GENERATED AND RADIATING HEAT IN THE INFRA-RED REGION OF THE SPECTRUM TOWARD THE OPEN UNDERSIDE SO AS TO HEAT THE PORTION OF THE SUPPORTING SURFACE OVER WHICH THE HOUSING IS DISPOSED, AND MEANS FOR SELECTIVELY VARYING THE FUEL DELIVERED TO SAID NOZZLES.

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