US2054588A - Apparatus for burning liquid fuels - Google Patents

Description

Sept. 15, 1936- T. J. STEPHENS APPARATUS FOR BURNING LIQUID FUELS Filed June 22, 1953 2 Sheets-Sheet 1 nlxm . NRMMK INVENTCR BY WK 14 1 ATTORNEY T. J. STEPHENS 2,054,588

APPARATUS FOR BURNING LIQUID FUELS Filed June 22, 1933 2 Sheets-Sheet 2 Sept. 15, 1936.

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Q\ m w mm mm m m Patented Sept. 15, 1936 UNITED STATES PATENT OFFICE Application June 22,

1 Claim.

In the practice of burning liquid fuels it has been found diflicult to produce complete combustion at the instant of starting the fire, and equally diflicult to prevent an escape of some 5 quantity of unburned fuel at and following the instant of extinguishing the fire.

My invention relates to improvements in the method of and apparatus for burning hydrocarbon fuels, and specifically to the correlation of essential steps preparatory to such burning in cases where a gaseous atomizing agent, such as air or steam is used in conjunction with an ignition agent.

The present invention pertains especially to a method of and apparatus for feeding hydrocarbon fuel into a stream of air or steam having sufficient volume and flowing at sufficient velocity to atomize said fuel as fed, and to carry the atomized particles within a vehicular jet into the combustion zone.

-Under all conditions it is essential to cause the fuel-laden-jet to ignite immediately upon entering the combustion area, and it is especially important in some industries utilizing oil as a fuel to accomplish ignition and complete combustion without permitting any particle of unburned fuel to escape from the zone of combustion. A good example of the requirement is to be found in such operations as the baking of foods and roasting of coffee in ovens heated .by oil fires under circumstances such that the products of combustion from the fire envelop the foods being baked or coffee being roasted. In such operations as these if the slightest amount of fuel escapes from the combustion chamber unburned, the product of the oven will be proportionately injured, the commercial value of such products being based largely upon the delicacy of their flavor or aroma which if contaminated by unburned fuel must inevitably be injured or wholly destroyed. V In the operation of an oil fire the critical stages, ,or those stages of operation in which completeness of combustion is most difiicult to attain, are found in starting and in extinguishing the fire. As evidence of this fact city smoke prevention ordinances usually provide for a certain number of minutes after starting a fire during which the ordinance is not to be effective, in recognition of the difficulty encountered in starting a fire without production of smoke.

-With the foregoing in mind it is the purpose of the present invention to provide a method of relatively simple steps arranged in practicable 5. sequence and a preferred form of mechanical de- 1933, Serial No. 677,049

vice, for carrying out said method, of simple and inexpensive construction whereby, for starting a fire, ignition conditions are established in the zone of combustion and also atomization conditions are established, at the point of fuel admission to said zone, both in advance of the delivery of any fuel to the atomizing mechanism or the combustion zone; and whereby, for extinguishing the fire, ignition conditions in the zone of combustion and atomization conditions in the atomizing mechanism both are maintained until after all delivery of fuel has ceased, thereby sweeping out and completely burning the last particle of fuel before discontinuing either of said essential conditions.

Another object of my invention is to provide a simple, practical and reliable method of, and apparatus for, regulating an oil fire to any desired volume of heat production and quality of flame within its range of capacity, and to thereafter readily extinguish and re-establish said fire at will without changing or disturbing the said regulation, and without escape of the slightest particle of unburned fuel upon extinguishment or re-establishment of the fire.

Other objects of my invention will be apparent from the detailed description thereof and an illustrative embodiment of an apparatus which constitutes only one of the means whereby the method of my invention may be effected.

In my method and by the device hereinafter described, the liquid fuel and air are fed under pressure to a burner in their separate conduits and are joined by a third carrying the gas for ignition purposes, the jet for the gas being arranged adjacent the atomizing nozzle of the burner and supplying a flame which is directed into the path of the atomizing jet projecting fuel from the nozzle. The three sources of fuel, air and a gas, respectively, are subjected to a control at the burner, whereby first the volume of the ,gas flame is increased, thus establishing an ignition condition, then the air is released in the burner, thus establishing the atomizing condition, and finally the fuel itself is released in the burner and is instantly atomized and ignited upon contact with the gas flame. To shut off the burner, the reverse steps take place, i. e. the fuel is the first to stop flowing, the air next, and finally the gas is cut down to a small pilot flame; as a result, there is no possibility of any unatomized or unignited fuel being at any time discharged from the burner into the combustion chamber either when the fires are started or when they are extinguished.

In the drawings, Figure 1 is a side elevational view of the oil burning system according to my invention; Figure 2 is a substantially longitudinal sectional view of the burner and control therefor in full open position; Figure 3 is a substantially transverse sectional view of the oil passage taken on lines 33 of Figure 2; Figure 4 is a substantially transverse sectional view of the passage for the atomizing agent taken on lines 4--4 of Figure 2; Figure 5 is a transverse section of the oil nozzle and burner tip; and Figure 6 is a side elevational view of the oil feed nozzle.

Referring to the drawings and particularly to Figure 1, III denotes the fuel oil pump and air pump from which an oil line H and air line I2 lead off to supply a burner I3 which is directed into an enclosure forming the combustion zone A. Ignition is supplied by gas from a line I4 running from its source to a position adjacent the other lines I I and I 2 at the burner.

The burner I3 in the present embodiment, comprises a metal casting having superposed cylindrical portions, the upper portion thereof housing the chamber for the fuel and air and the lower or under portion carrying the control elements for oil, air and ignition. The oil and gas lines I I and I4, respectively, connect to the burner casting along the under side of the lower or control cylindrical portion, the air line I2 entering the burner at the side thereof and on a line intersecting the axis of the control portion.

The chamber constitutes an axial bore 5 having a threaded restricted opening I6 formed by a wall I! within the chamber. The wall divides the chamber into two sections, the rear section for oil communicating with the oil line I I through a passage I8. The open or rear end of the latter section is internally threaded and is provided with a screw nut I9 having an enlarged central flange and externally threaded shank 2|. The nut I9 is provided with an axial bore 22 which is threaded and receives the threaded sleeve 23 of a needle valve 24, the latter consisting of a spindle extending beyond the opposite ends of the nut I9, the inner end having a reduced portion 25 provided with tapered slits 26 through which the fiow oil from the chamber is controlled or regulated. The outer end of the spindle carries a hand wheel 2'! and a packing nut 28 encircling the spindle is screwed down over the threaded shank 2|.

The reduced end 25 of the spindle is adjustably projected into a bore 29 of a tubular member 30, which is threaded at its ends, one thereof being screwed into the threaded restricted opening I6 in the chamber wall I'I, while the opposite end carries a nozzle 3|. The tube 30 carries the oil from the oil section of the chamber, past the needle valve 24 to the nozzle 3| the latter having a shank 32, which is square in transverse section, and which tapers off at its free end, as illustrated particularly in Figures 5 and 6. The bore of the nozzle 3| also tapers down to a smaller opening at its delivery end. In order properly to arrange the tubular member 30 in the air chamber, a collar 33 is provided at the end of the threads entering the restricted opening I6,

' so that the collar 33 seats against the wall I1.

The reduced end 25 of the needle valve is ground to have a sliding fit in the bore of the tubular member 30, as illustrated in Figure 2. The outer end of the air section of the chamber is increased in size and internally threaded to accommodate vthe threaded shank of a nozzle tip 34, the latter having a bore 35, the diameter of which corresponds to the length of the diagonal of the square shank of the nozzle 3|, so that in operation the latter is always assured of perfect centering within the tip 34, the spaces between the flat faces of the nozzle 3| and wall of the bore 35 providing air passages. The outer or delivery end of the tip 34 is tapered ofi short and provided with an orifice 36 of a size to surround the tip end nozzle 3|, as shown in Figure 2.

Air is led into the air section of the chamber through an angular passage 31 leading towards the control section of the burner casting from the inlet to the air line I2. The control elements for the oil, air and gas comprise a rotary valve spindle 38, which is in a single piece and which turns on an axis parallel to the axis of the oil and air chamber and coincident with the axis of the lower cylindrical portion of the burner casting. On one end of the spindle 38 is a tapered section 39, which turns in a correspondingly tapered bore in the casting, and which is provided with a threaded tip 40 projecting beyond the delivery end of the burner casting to receive a washer 4| and nut 42. The opposite end of the spindle 38 is straight and projects through a packing chamber 43, which is formed by the continuation of the tapered bore, a packing nut 44 being screwed into the chamber against the packing 45 which abuts a washer 46 at the inner end of the chamber. The outer end of the spindle 38 beyond the packing nut 44, is keyed to a lever or handle 41, which is provided with a projection 48 adapted to engage stops 49 projecting from the wall of the casting at an effective angle of approximately 90 from each other.

The tapered portion of the spindle 38 is provided with a substantially transverse bore 50, which in the open position of the control valve registers and alines itself with the passage l8 for oil between the line H and oil section of the chamber. Beyond the bore 50 and disposed in line with the angular air passage 31, the tapered valve section 39 is provided with a transverse slot 5| of sufiicient length to more than embrace the ends of the vertical and lateral portions of the air passage I8, so as to admit air through the passage I8 to the air section of the chamber before the valve is fully open, as illustrated in Figure 4.

Beyond the air slot 5|, the spindle 38 is provided with a central bore 52, the outer end thereof being threaded to receive the stem 53 of a pilot burner 54 which is slightly oifset with respect to the axis of bore 52 and projects beyond the delivery end of the burner tip 34. The inner end of the bore 52 branches off at an angle and opens out onto the tapered surface of the spindle 38 through a slot 55 which is of a length approximately one quarter of the circumference, so that during its movement to open position of the valve the gas will be permitted to flow to the pilot in full force before the oil begins to flow. The slot 55 communicates with the gas line H through a passage 56 leading therebetween and being disposed in the burner casting. In order to maintain a small flow of gas to the pilot at all times, a bleed opening 51 is arranged in the casting between the valve and the passage 56, the opening 5! being provided with a screw valve 58 and opening into a circumferential groove 59 in the surface of the valve. A radial passage 60 in the valve completes the communication between the groove 59 and the central bore 52.

In operation, the rotary valve in its closed position brings the handle 41 in the position, illustrated in Figure 1, with the projection 48 abutting the lowermost stop 49. In this position the oil, air and gas passages in the burner are cut off. To open the control valve and set the burner in operation, the handle is turned upwardly towards the right until the projection abuts the upper stop 49. During rotary movement of the valve the first passage to open is that admitting gas in sufficient volume to increase the flame in the pilot 54, thus establishing an ignition condition; then the air passage is cleared and air under pressure is released to the burner, thus establishing the atomizing condition; and finally the fuel oil itself is released to the burner as the valve reaches its full open position, shown in Figure 2. The fuel reaching the burner at this stage is instantly atomized and ignited upon contact with the gas flam'e. To shut off the burner the reverse steps take place, i. e., the fuel shuts off first, the air next and finally the gas flame is cut down to a small pilot jet.

In industrial plants utilizing oil heated ovens or other heating compartments, it may be necessary to close off the burners from time to time and by means of the present method and the apparatus herein described it is only necessary to move the handle 4! and spindle 38 in a clockwise direction, to its initial position, to effect the gas for ignition, air for atomizing and oil to supply the fuel, the order of closing is just the reverse, i. e., the oil is cut oif first, then the air sweeps the nozzle clear of fuel and stops, and finally after every particle of fuel has been consumed, the gas is turned low.

While I have described my method and a preferred apparatus for carrying out that method, it is understood that my invention is not to be limited to the particular details disclosed, the invention as to the method of being capable of performance by other apparatus and the apparatus being capable of various embodiments in addition to that illustrated.

Having now described my invention, what I claim and desire to secure by Letters Patent is:-

An atomizing liquid fuel burner comprising a housing including an atomizing nozzle, fuel and atom'izing fluid passages communicating with said nozzle, a large gas passage, a small gas passage, a valve body extending through said housing and having an axial bore extending inwardly from the end near the nozzle in constant communication with said small passage, and ports controlling the flow of fuel and atomizing fluid to said nozzle and gas to said bore and operable when moved from closed to open position to sequentially open the large gas, atomizing fluid and fuel passages, and a pilot burner offset in respect to and in communication with said bore and carried by and movable with said valve bod y THOMAS J. STEPHENS.

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