US2253175A - Fuel burner - Google Patents

Description

Aug. 19, 1941. A. s. GERQUEST FUEL BURNER Filed Oct. 19, 1940 2 Sheets-Sheet 1 INVENTOR flr/kur 5. 00' aeq/ Aug. 19, 1941. A. s. GERQUEST FUEL BURNER Filed Oct. 19, 1940 2 Sheets-Sheet 2 tiff/tar INVENTOR J1 fiezyawf BY l/ 1 I 'RNEY of air to flow through the burner opening it which is substantially uniform across the entire area thereof. This air under pressure on the surface of the fan blades mixes with the film of fuel thereon to form a combustible mixture which burns on the surface 28 of the blades to produce a flame which extends from the surface of the blades substantially helically through the burner opening l2 and into the combustion chamber iii of the furnace.

Fuel may also from the open end 20 of the The fuel which is thus discharged is thrown outwardly by centrifugal force from the end of the shaft and is picked up by the portion of the surface of the fan blades which is positioned forwardly of the plane of the end 20 of said drive shaft to assist in forming a fllm thereon.

It is to be understood that, if the shape of the blades is such that the desired supply of fuel may be obtained centrlfugally from the end of the drive shaft, the ducts 21 may be omitted. In other instances it may be desirable to close the end of the drive shaft and rely upon the ducts 21 for supplying fuel to the surface of the blades or a plurality of such ducts may be associated with each blade and spaced thereover. Furthermore, the ducts 21 have been shown as cast into blades merely for convenience. The ducts may comprise separate supply pipes rotating with the blades and terminating in a position to supply oil onto the forward surface thereof, as shown in Fig. 3 (to be described).

The supply of air for combustion purposes may be regulated by means of the bafiie i1 so as to obtain the proper combustion conditions. The bafiie i1 may be adjusted axially of the hub it so as to vary the opening into the burner throat ii. The air supply may also be adjusted by varying the air plenum chamber, not shown, the burner throat or in the furnace itself.

After the above adjustment has been made for presetting the combustion conditions, the instantaneous supply of air is thereafter dependent upon the speed of the burner fan. The quantity of fuel supplied to the burner, being dependent upon the speed of the pump 88, is also proportional to the speed of rotation of the burner fan. Consequently, by adjusting the speed of the motor 25, both the air and fuel supply to the burner may be controlled in a proportional manner so as to vary the operating capacity ofthe burner while maintaining predetermined optimum combustlon conditions at all leads.

It has been found that in a burner of the above type the capacity may be varied over a wide range without producing instability of ignition. The burner, for example, may be operated at full capacity or may be operated at a reduced capacity, even as low as half of the full capacity while maintaining efficient combustion conditions and without any tendency for the flame to become unstable. The burner is accordingly adapted for variable loads and. as applied to household use, may be used to provide continuous or substantially continuous combustion and thereby eliminate the undesirable effects produced by intermittent combustion.

The burner is not restricted to use in a furnace but may be adapted to various other uses. If not confined by a burner throat or the like. the flame. of course. tends to spread out in the form of a cone or disc. This, however,

the fan blades drive shaft It.

be supplied to asssuvs does not interfere with the stability of combustion.

In the embodiment of the invention shown in Figs. 3 and 4. the fan construction is generally similar to that described above and corresponding parts have been identified by similar reference numbers. In this e bodiment the end 20 of the shaft is is closed by a cap ill and a lurality of ducts 5| extend from the end of the shaft is above the forward surface of the blades 2i adjacent the leading edge 28 thereof. These ducts ii are provided with openings BI which are shown as spaced therealong so as to supply fuel over a substantial portion of the blade area. The ducts Ii supply fuel to the forward surface of the fan blades for burning thereon. It is to be understood, however, that the ducts may be formed in the blades themselves as in Fig. l or that the outside ducts ii of Fig. 3 may be used in the embodiment of Fig. i if desired. The ducts Ii should be positioned so as not to interfere with the fan action and may be made thin in section.

A rim N is shown a part of the fan casting and extending around the periphery of the rotor beyond the ends of the fan blades 2 I. The rim ll extends forwardly a substantial distance beyond the forward plane of the fan blades. In the event that fuel is thrown from the blades 2|, this fuel impinges against the inner surface of the rim H and burns thereon. The operation is similar to that described above except that the rim ll causes the flame to retain a substantially helical form. This embodiment may be used in combination with a furnace as shown or may be used independently for other heating purposes inasmuch as the shape of the burner throat is not relied upon to control the flow of air for combustion.

In the embodiment shown in Fig. 5 the benefical effects of the forms of both Figs. 1 and 3 are obtained. In this embodiment the construction is similar to that of Fig. 1 with the exception that the blades Ila are inclined forwardly beyond the plane of the end 20 of the hollow drive shaft is. This forward inclination of the blades produces in the air flow a radial component toward the axis and thereby assists in maintaining a concentrated flame. The forward inclination of the blades also provides a greater surface forwardly of the plane of the end of the hollow drive shaft and makes a larger blade area available for receiving fuel which is discharged centrifugally from said shaft. This construction also reduces the tendency for the fuel to be thrown from the surface of the blades onto the burner throat.

If desired, the blades Il may be faced with a refractory absorbent material. such as asbestos, with suitable provision for discharging fuel from the ducts 21 or from the end of the drive shaft onto the asbestos facing. The fuel then forms a film over the asbestos facing and burns thereon. The refractory protects the metal of the blades themselves and it may be renewed when necessary.

In all of the above embodiments the baffle H, in addition to providing means for adjusting the air flow. also shields the motor II from the radiant heat of the burner. It has been found that the passage of air over the rapidly rotating blades and over the radial arms it serves to cool the same and prevents the heat of the furnace from injuring the blades or the metal arms even when operating continuously.

in Figs. 3 and i as forming I tration, it is to be understood that the invention is not to be limited thereto, but that various changes and modifications may be made as will be readily apparent to a person skilled in the art. The invention is only to be restricted in accordance with the scope of the following claims.

What is claimed is:

1. A fuel burner comprising a fan of the propeller type having blades adapted to induce an axial flow of air and to discharge said air forwardly, means driving said fan, fuel supply means including ducts rotating with said fan and terminating in the forward surface of said blades in a position to supply fuel directly onto said surface and to cause the same to form a film thereon in contact with the air induced by rotation of said blades, whereby a combustible mixture forms on the surface of said blades for burning thereon, said fan being positioned and arranged to discharge the burning combustible mixture axially.

2. A fuel burner comprising a fan of the propeller type having blades adapted to induce an axial flow of air and to discharge said air forwardly, means driving said fan, fuel supply means including ducts rotating with said fan and terminating in a position to supply fuel directly onto the forward surface of said blades and to cause the fuel to form a film thereon in contact with the air induced by rotation of said blades, whereby a combustible mixture forms on the surface of said blades for burning thereon, said fan being positioned and arranged to discharge the burning combustible mixture axially.

3. A fuel burner comprising a fan of the propeller type having blades adapted to induce an axial flow of air and to discharge said air for: wardly, means driving said fan, said drive means including a hollow drive shaft, means to rotate said shaft, means supplying fuel to said drive shaft, said fan blades having ducts communicating with said drive shaft and terminating in the forward surface of said blades in a position to supply fuel directly onto said surface to cause same to form a film thereon in contact with air induced by rotation of said blades, whereby a combustible mixture forms on the surface of said blades for burning thereon, the fan being positioned and arranged to discharge th burning combustible mixture axially.

4. A fuel burner comprising a fan of th propeller type having a hollow, open ended hub and having blades extending forwardly of the plane of the open end of said hub, said blade being adapted to induce an axial fiow of air and to discharge said air forwardly, means driving said fan including a hollow drive shaft carrying said hub, means supplying fuel to said drive shaft, and means rotating said drive shaft to cause fuel to be thrown outwardly from the open end thereof onto said forwardly extending fan blades and to form a film thereon in contact with air induced by rotation of said blades whereby a combustible mixture forms on the surface of said blades for burning thereon, the fan being positioned and arranged to discharge the burning combustible mixture axially.

5. A fuel burner comprising a fan of the propeller type having blades adapted to induce an axial flow of air and to discharge said air forwardly, means driving said fan, said drive means including a hollow drive shaft, means to rotate said shaft, means supplying fuel to said drive shaft, means to supply fuel from said drive shaft onto the forward surface of said blades in a position well in advance of the trailing edge thereof to form a film thereon in contact with the air induced by rotation of said blades, whereby a combustible mixture is formed on the surface of said blades for burning thereon, the fan being positioned and arranged to discharge the burning combustible mixture axially.

6. A fuel burner, comprising a fan of the propeller type having blades adapted to induce an axial flow of air and to discharge said air forwardly, means supplying liquid fuel to the forward surface of the rotating fan blades to cause the same to be mixed thereon with the air induced by rotation of said blades to form a combustible mixture, said fan being positioned and arranged to discharge the burning combustible mixture axially, means driving said fan and means actuated by said drive means to control said fuel supply means so as to supply fuel at a rate which varies in accordance with the speed of rotation of said fan, whereby the ratio of fuel and air is maintained substantially constant as the capacity of said burner is changed by varying the speed of said drive means.

7. A fuel burner, comprising a fan of the propeller typ having blades adapted to induce an axial flow of air and to discharge said air forwardly, means supplying liquid fuel to the forward surface of the rotating fan blades to cause the same to be mixed thereon with the air induced by rotation of said blades to form a combustible mixture, said fan being positioned and arranged to discharge the burning combustible mixture axially, means driving said fan, a fuel supply pump of the positive displacement type having a capacity dependent upon speed of operation and means actuated by said drive means to drive said pump so as to supply .fuel at a rate which varies in accordance with the speed of rotation of said fan, whereby the ratio of fuel and air is maintained substantially constant as the capacity of said burner is changed by varying the speed of said drive means.

8. A fuel burner comprising a fan of the propeller type having blades adapted to induce an axial flow of air and to discharge said air forwardly, means driving said fan, fuel supply means rotating with said fan to supply fuel onto the forward surface of said blades to cause the same to form a film thereon in contact with the air induced by rotation of said blades, whereby a combustible mixture forms on the surface of said blades for burning thereon, said fan being positioned and arranged to discharge the burning combustible mixture axially, and an axial rim disposed around the periphery of said blades to receive fuel which may be thrown outwardly therefrom and to cause the flame to retain a substantially helical form.

ARTHUR S. GERQUES'I.

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