US2177781A

US2177781A - Liquid fuel burner

Info

Publication number: US2177781A
Application number: US226822A
Authority: US
Inventors: George P Haynes; Letvin Samuel
Original assignee: TODD COMB EQUIPMENT Inc
Current assignee: TODD COMB EQUIPMENT Inc; TODD COMBUSTION EQUIPMENT Inc
Priority date: 1938-08-25
Filing date: 1938-08-25
Publication date: 1939-10-31
Anticipated expiration: 1956-10-31

Description

G. P. HAYNES El AL LIQUID FUEL BURNER Oct. 31, 1939.

Filed Aug. 25, 1958 INVENTORS [Magge j? fiayws 6mm! [05mm ATTORNEY Patented Oct. 31, 1939 UNITED STATES PATENT OFFICE LIQUID FUEL BURN Application August 25, 1938, Serial He. was

6 Claims.

This invention relates to liquid fuel burners having excess fuel return means for use with automatic combustion controldevices which operate to maintain a constant steam pressure on boilers in accordance with the steam requirements therefrom.

For proper atomization of liquid fuel it is desirable that the pressure with which the fuel is supplied to the burner atomizing orifice shall be constant, as a variation in the delivery pressure affects the character of the,spray entering the combustion chamber.

Therefore we have found it necessary to evolve a means whereby the fuel return may be caused to emanate from a point in advance of the usual atomizing orifice and to this end we have devised a second or end orificed plate, spaced from the usual atomizer plate, the orifices of said plates being co-axial, and said end plate becoming the atomizer plate. The space intermediate the plates constitutes a chamber and it is from this chamber that excess fuel bleeds for return to its source, by which means the quantity of fuel atomized into the furnace can be varied within a.

wide range without modifying the pressure flow of the fuel for atomization.

The liquid fuel, which is delivered fromv a pressure source through a central tube is causedto enter whirlingly by way of tangential slots into 0 a chamber that is provided with an axial outlet orifice. Because of the pressure a high centrifugal effect is produced by the whirling fuel, setting up a vortex action therein so that it acquires a hollow core whose surrounding wall comprises the fuel that is to be atomized, wholly or in part, upon issuance from the orifice in the end or atomizer plate.

Means are provided, within the space separating the two orificed plates, for withdrawing a portion of the fuel that has entered said space and is whirling therein, such withdrawn quantity being regulated by suitable control means, leaving only a desired quantity of fuel to be atomized.

In thus reducing the quantity of fuel to be issued from the atomizer, the remainder returning to the source, we have employed an annulus that presents an inclined wall to fuel entering the space between the two plates, said annulus having a series of bleeder holes that "communi- 5 cate with the fuel return tube and serve as brak-- ing means to retard the rotation speed of the fuel in said space, whereby it is more effectively caught by said holes, thus enabling a larger quantity of fuel to be retiu'ned than would otherwise be pos- 55 sible,

It is desirable in a wide range burner to enable the return of a maximum quantity of fuel when a minimum quantity thereof is to pass into the furnace, and to increase the quantity of fuel to be atomized while proportionately reducing the 5 quantity thereof for return. These desiderata are efliciently accomplished by means of our invention which will be'explained more in detail hereinafter.

Other features and advantages of our inven- 10 tion will hereinafter appear.

In the drawing:

Figure 1 is a longitudinal sectional view of our improved liquid fuel burner, with fuel return means, the usual air supply means not apl5 pearing, and a portion of the housing screw only representing the usual housing.

Fig. 2 is an end view thereof.

Fig. 3 is an enlarged section showing the forward portion only of the burner, and

Fig. 4 is a section on the line 4-4 of Fig. 3.

In said views let I indicate the usual coupling member, having the handle 2, and 3 indicates a union bushing which is provided with the ports 4, 5 that respectively connect with the source of 25 fuel supply (not shown) and with passageways 6, l in said-coupling member.

The burner haswan outer tube 8 and an inner tube 9, these tubes being in spaced relation to provide an intervening passageway A. Tube 8 is so threaded into coupling member I as at I 0, and tube 9 is shown as entered through an aperture in a partition II that divides the interior of the coupling member into compartments l2 and i3, said tube 8 having an open ended ferrule N that 35 is screwed into a boss IS on partition II, and a space remaining for packing material at l6 between the ferrule and boss to provide a liquid tight connection.

Compartment l2 receives fuel under pressure 40 0 through passageway 6 and port '4 and delivers it assembly, which is more clearly illustrated in Fig. 3.

The nozzle body, I1, is threaded upon tube 8 and receives the cap i8, following the regular practice of the Toddtype burners. Also, the nozzle body is interlorly threaded at l9 to receive the screw end of tube I, and its adjacent end is provided with a concentric series of holes 20 that are in communication with tube 9. The closure plate 22 is placed against the nozzle body, having an annular groove 23 that registers with holes 20; also having a central whirling chamber 24 which is in communication with groove 23 by way of tangential slots 25 formed through the wall 26 that separates chamber 24 from groove 23.

Liquid fuel supplied under a predetermined working pressure through tube 9 is caused to whirl in chamber 24, from which it issues through orifice 21 in a whirling stream. Ordinarily orifice 21 would cause atomization of the fuel, but in the instance of our present invention an added member is introduced in the form of a terminal or end plate 28, positioned in advance of plate 22 and spaced therefrom to provide the chamber 29, said plate 28 having an atomizing orifice 30 that is co-axial with, and preferably, as shown in the drawings, of the same diameter as orifice 21. Chamber 29 is in communication with fuel return passageway A through holes 3| provided in plate 22 and holes 32 that extend through nozzle body H, the nozzle body having a groove Ila that forms the entry to holes 32.

Orifice 21 is provided with a flared exit mouth 21a permitting the whirling fuel leaving said orifice to more readily disperse into chamber 29, and the forward face of plate 22 is given an annular recess 22a that is bounded by an outwardly inclined wall surface 221), from which surface the holes 3| extend through plate 22 for communication with nozzle body holes 32.

The edges of holes 3| lying in the inclined wall surface 22b have the effect of retarding the rotation speed of the fuel whirling in chamber 29, so that the fuel, instead of merely spinning around in said chamber and failing to return to the source the full quantity thereof required by the return control setting, is actually caught by these holes 3| and caused to enter and pass through said holes. By these means therefore the full capacity of the controlled return is satisfied and hence the quantity of fuel remaining for atomization can be accurately regulated, while the pressure under which the fuel is supplied to the burner remains constant.

It will be noted that the inner surface of plate 28 surrounding atomizing orifice 30 is depressed to provide an annular recess in chamber 29 forming a lip 30a that approaches or even lies slightly within the plane area encompassed by the annular, inclined wall surface 22b. This lip, which constitutes an apical formation surrounding orifice 30, performs the function of peeling off the outer portion of the tubular. formation comprising the whirling fuel whose remainder is to traverse said orifice, the quantity of -fuel thus removed being proportionate to the controlled capacity of the fuel return line.

The control means are not herein shown, being of known character, and may be applicable with one or more burners, either for use with a single boiler or a battery of boilers, so that all burners can be controlled simultaneously.

As stated above, for proper atomization with constant character of the spray entering the combustion chamber, the pressure with which the fuel is supplied to the usual atomizing orifice 21 should be constant. Provided that the orifice 30 is at least as large as the orifice 21, as shown in the drawing, the fuel will issue from the orifice 30 with the same velocity as it issues from the orifice 21 and no back pressure will be built up in the return chamber 29. If such a back pressure existed in the return chamber, it would vary depending on the controlled amount of oil permitted to return through the passageway A, and since the pressure would be transmitted to the whirling chamber 24, the character of the spray would not be constant.

Variations within the spirit and scope of our said invention are equally comprehended by the foregoing description.

We claim:

1. The combination in a liquid fuel burner having a delivery passageway and a return passageway, of a closure plate having an emission orifice, means for causing the fuel to whirl before traversing said emission orifice, an atomizing plate fitting over said closure plate and having an atomizing orifice that is axially aligned with the orifice in said closure plate, a return chamber disposed intermediate said plates and having communication with said return passageway, and means comprising an interrupted projection extending from the plane of said closure plate toward said atomizing plate for retarding the rotative speed of the oil in said chamber.

2. The combination in a liquid fuel burner having a delivery passageway and a return passageway, with an end member having a depressed portion that is provided with an apical atomizing orifice, a closure member having an emission orifice, co-axial with said atomizing orifice, that is provided with a fiared outlet, and means for causing the fuel to whirl before traversing said emission orifice, said closure member being spaced from said end member to provide a. return chamber therein, said chamber being in communication with said return passageway, the depressed, orificed portion of said end member serving to separate the controlled return quota of rotating fuel from the quota thereof to be atomized, for delivery of said return quota to the return passageway.

3. The combination in a liquid fuel burner having a delivery passageway and a return passageway, with an end member having a depressed portion that is provided with an apical atomizing orifice, a closure member having an emission orifice that is provided with a flared outlet, said orifices being co-axial, said closure member being spaced from said end member to provide a fuel return chamber therebetween, said closure member having an annular recess and an inclined wall bounding said recess, said wall being pierced with a series of holes communieating with said return passageway, the edges of said holes serving to retard the rotation speed of the fuel rotating in said chamber, whereby the full return controlled quota of fuel, separated by the depressed, orificed portion of said end memher from the quota to be atomized, is caused to be directed into said return passageway.

4. The combination in a liquid fuel burner having a delivery passageway and a return passageway, with an end member having a depressed portion that is provided with an apical atomizing orifice, a closure member having an emission orifice that is provided with a flared outlet, said orifices being co-axial and of the same diameter, said closure member being spaced from said end member to provide a fuel return chamber therebetween, said closure member having an annular recess and an inclined wall bounding said recess, said wall being pierced with a series of holes, communicating with said return passageway, whose edges serve to retard the rotation speed of the fuel rotating in said chamber, whereby the full return controlled quota 6f fuel, separated by the depressed, orificed portion of said end member from the quota to be atomized, is caused to be directed into said return passageway.

-5. The combination in a liquid fuel burner having a delivery passageway and a return passageway, of a closure plate having an emission orifice, means for causing the fuel to whirl before traversing the emission orifice, an atomizing plate fitting over said closure plate and having an atomizing orifice that is axially aligned with the orifice in said closure plate, the diameter of the atomizing orifice being at least as large as the diameter of the emission orifice, said closure plate being spaced from said atomizing plate to provide a fuel return chamber therebetween, said closure plate having an annular recess and an inclined wall bounding said recess, said wall being pierced with a series 01' holes communicating with said return passageway, the edges of said holes serving to retard the rotative speed of the fuel rotating in said chamber.

6. The combination in a liquid fuel burner having a delivery passageway and a return passageway, of a closure member having an emission orifice, means for causing the fuel to whirl before traversing the emission orifice, an end member that is provided with an atomizing orifice, coaxial with said emission oriflce, the diameter of the atomizing orifice being at least as large as the diameter of the emission orifice, said closure member being spaced from said end member to provide a return chamber therein, said chamber being in communication with said return passageway, and a circumferential lip on said end member surrounding said atomizing orifice and extending inwardly toward the closure plate and toward the axis of the orifices, said lip serving to separate the return quota of fuel from the quota thereof to be atomized.

GEORGE P. HAYNES. SAMUEL LETVIN.