US2502664A - Gun type oil burner - Google Patents

Description

11 1950 R. E. NEST 2,502,664

GUN TYPE OIL BURNER Filed Oct. 6, 1947 s Sheets-Sheet 1 INVENTQR. RICHARD E. NEST ATTORNEY Aprifl 4, 1950 R. E. NEST 2,502,664

GUN TYPE OIL BURNER I s Sheetsl-Sheet 2 Filed Oct. 6, 1947 v vq M I W a!" 15 I w W 3 L w m D O i a s N a INVENTOR.

RICHARD "1 NEST BYM W ATTORNEY April 4, 11950 I NEST 2,502,664

GUN TYPE OIL BURNER Filed 001). 6, 1947 3 Sheets-Sheet 3 INVENTOR. RICHARD 5. N53? Patented Apr. 4, 1950 UNITED STATES ATENT OFFECE GUN TYPE OIL BURNER,

Richard E. Nest, Baltimore, Md., assignor to The General Oil Burner Corporation, a corporation of Maryland 6 Claims.

This invention relates to combustion burners adapted to burn fluid fuels, and more particularly to pressure atomization for use with liquid hydrocarbon fuels.

In the early development of oil burners little thought was given to the proper mixing of the air and oil spray for combustion purposes. The fires did not burn clean even when excessive amounts of air were used which reduced the carbon-dioxide concentration of the waste gases to 6 or 7% by volume. This method wasted con siderable fuel.

Further improvement of the pressure atomizing burner with respect to the combustion results revolved around the fact that by imparting a spiralling or rotating motion to the air within the blast tube of the burner the resulting combustion reaction could be noticeably improved. Numerous and ingenious devices consisting essentially of directing vanes were developed with generally improved results. There followed a period wherein a carbon-dioxide concentration of 10% without objectionable smoke was adopted as a laboratory test standard and seemed to be the limit. With the present dependence upon petroleum products and its problem of supply new and more economical refining methods are required to supply the demand. The process of catalytic cracking came to the front and with it a change in the chemical structure of the fuel oil molecule. This change of structure set up a new set of conditions for the oil burner and while the carbon to hydrogen ratio changed in such a way as to require slightly more air per gallon of fuel burned the increase was not suilicient to provide the velocity required nor was the problem one of the plain forward velocity. In general when air is caused to rotate or spiral through the blast tube of an oil burner the molecules that make up the air stream have imparted to them at least two directional forces. One of these forces may be considered as a forward component While the other tends to deflectsidewise by reason of whatever obstruction or deflecting means started the motion. So long as such an air stream is confined within a tube said stream Will revolve within those confines. To some degree an inwardly converging restriction in the discharge end of the blast tube will increase the rotational speed at the point of discharge. principle is the basis for the design of the nozzle used to spray the fuel oil. However, upon leaving the confines of the tube the air particles still endowed with propelling energy will not continue along any similar path as was followed within the This 2 tube. They assume a new path or trajectory and due to the effect of the above mentioned dual directional forces assume a relatively straight line flight, the path of which is a resultant lying somewhere between the forward direction and the side one.

The resulting pattern if reproduced photographically would appear in the shape of a hollow cone diverging from the source. counteracting forces will enter into the movement of the air particles and the final conditions within a flame so supplied with air will be indeterminate. Such conditions as above described, will also set up at least one result that is less favorable to the successful operation of the burner. By exploring the opening at the discharge end of a blast tube by means of an impact tube and manometer there will be found to exist an area centrall located and concentric with the opening that shows negative gauge pressures while adjacent to the walls or orifice the pressure will be positive. This condition will in operation cause unburned sooty deposits to form on the fuel nozzle and the electrodes. The recirculating hot gases and burning products often cause excessive carbonization of these parts. Various means have been applied to overcome these objectionable features with more or less success. When attempting to burn very small quantities of oil, about one gallon per hour or less, the amount of air becomes proportionately less, striving for higher efficiencies reduces the air volume still further. The fuel nozzle and the ignition electrodes are positioned in spaced relation to each other and of necessity, require certain clearances with respect to the orifice or opening at the end of the blast tube. Thus a minimum opening size is established without any consideration being given to the air flow. If the air velocity is reduced to satisfy the metering effect of the orifice said velocity will be insufficient to effectively mix the fuel spray and air with the result that the fire will be extremely dirty and may even smother for want of oxygen at the proper location. The answer will be found in the two directional force theory to be described in this application. By separating the main air stream into a multiplicity of overlapping streams of air issuing into a form that resembles ribbons, as with the air register under discussion. it has been found that within limits the air can be given an initial directing force similar to the result obtained when using a conventional form of air deflector. By arranging the louvre shaped openings on a conically shaped surface the gross area may be increased while maintaining the minimum of slot width. Such a relationship results in a better jet action and maximum deflection of the air streams. The concave side of the air register when on the fire side further provides a most effective chamber for the mixing or blending of the multiple issuing jets of air. By partially restricting or deflecting these multiple air jets by means of proportioned orifices located concentrically with the air register and at a point of greatest diameter the control of the final delivery is accomplished. A minimum sized orifice delivers a minimum amount of air while all the air is deflected at least twice prior to final discharge. With an increase of orifice size the second deflecting action is proportionally decreased while the air deflected only once is discharged in essentially the desired direction.

The main air stream controls the shape and quality of the resulting combustion and by the introduction of a stabilizing air stream into the vortex of the said resulting action controls the point of flame front or flame propagation.

The result of these forces is manifest in a fire at all rates that is active due to relatively high air velocities. Said fires are eificient due to this velocity discharge with proportioned air volumes. Also of importance the fire is highly stable due to the resulting stable vortex at the point of flame propagation.

It is an object of the present invention to deliver fuel and air in such proportions that combustion may be readily established through ignition means and continue thereafter under equilibrium conditions of exothermal reaction while maintaining maximum efiiciencies.

It is an additional object of the present invention to provide a gun type burner having improved means fo supplying main and stabilizing air streams and directing them in controlled relationship to each other and to the oil spray, characterized by the production of a steady, stable and quiet flame of high temperature and by improved efficiency of combustion.

It is an additional object of the present invention to provide a gun type burner having an improved method of introducing air for the purpose of combustion with respect to the oil spray and comprises in changing the size of the orifice in the nose piece to suit the size of the fire required, it being noted that as the orifice opening is increased more air goes off tangentially causing a reduction in the whirling action.

It is an additional object of the present invention to provide an outer tube and a dividing tube to guide the main air stream to the nose piece orifice and having means for supplying a controllable stabilizing air supply to control the point of flame propagation so it will occur at a point outside of the nose ring and prevent the creation of a vacuum which would cause the combustion to take place in back of the nose ring.

It is an additional object of the present invention to provide an oil burning means in which increasing the orifice opening will cause more air to leave the burner tangentially, with the resulting reduction of the whirling action of the air to produce better combustion with less heat losses.

It is an additional object of the present invention to provide an oil burner with air controlling means to more effectively burn the aromatic fuels produced through catalytic cracking.

It is an additional object of this invention to provide an oil burner having nose pieces provided with orifice opening proportioned to suit the size of oil nozzle used and providing a stabilizing air supply preferably adjustable from the outside of the burner to enable the oil burner to burn cleanly and be free from objectional combustion rumbling and pulsations while maintaining combustion efilciency.

t is an additional object of this invention to provide air control means which can be adapted to existing fuel oil burners to enable them to be operated by catalytically cracked oils efficiently.

Other objects will become apparent as the invention is more fully set forth.

For a better understanding of the invention, its objects and the principles thereof, reference is made to the appended drawings and the following description, wherein together, is outlined and illustrated a particular form of the invention by wa of example, while the scope of the invention is indicated in the claims.

In the drawings:

Figure 1 is a side elevation of the oil burner embodying this invention with parts broken away to show its inner construction;

Figure 2 is an enlarged sectional view taken along lines 2-2 of Figure 1;

Figure 3 is a sectional view taken along line 33 of Figure 1;

Figure 4 is an end view, partly in section, of the burner looking in the direction of lines 4-4 of Figure 2;

Figure 5 is a sectional view taken along lines 55 of Figure 1;

Figure 6 is a sectional view taken along lines G-6 of Figure 1;

Figure '7 is a sectional view taken along lines 7-! of Figure 1;

Figure 8 is a sectional view taken along lines 88 of Figure 4.

Similar reference characters refer to similar parts throughout the drawings.

In the particular construction shown in the drawings, the fan housing is provided at its discharge opening with a blast tube 2 suitably attached to the fan housing I and in locking attachment to the discharge end of this tube is the burner nose piece 3, which is preferably in the form of a cup shaped stamping of heat resisting material. The bottom or fire end of said nose piece has an opening or orifice 4 therein preferably round and concentric with the main body thereof, the size of which depends upon the firing rate. This nose piece acts as a restricting member for the control of the air volume. At the lowest point of said nose piece 3 and on the same plane as the orifice 4, is a small opening 5 to prevent the accidental accumulation of oil in the blast tube 2. Inside the blast tube 2, and in removable attachment thereto is preferably positioned a supporting bracket 6, the fire end of which is suitably formed to both locate and support an inner dividing tube 1. The dividing tube 1, is preferably of tubular section having a conical restriction or transition 8, at its discharge end, said small end being provided with a groove 20 to receive and be mechanically affixed to the air register 9. The air register 9, is preferably a cup shaped section consisting of a vertical section essentially round in form and having a hole 2| therein of suitable size to conform and be fitted with the groove 20 of the restriction 8 of the dividing tube 1. From the outer periphery of said vertical surface the air register 9 continues in the form of a truncated cone, the sides of which diverge from the aforementioned vertical surface toward the firing end of the burner preferably as shown in F-igures '1 and 2. At the extreme diameter of said conicalsection the air register is terminated in a short section of parallel wall forming a cylindrical stiffening ring ill, said ring being of suitable dimension to slipinto positioning support of the nose piece 3. Figures 4 and 8 show an end view and section of the air register 9-. Located on the conical surfaces of said air register and in radially-spacedrelationship thereon are embossed a multiplicity of slit openings l I. Said openings being preferably in the form of louvres- H.

An oil line l3 passes through the fan housing 1 and extends along the longitudinal axis of the blast tube 2 and dividing tube 1, and is suitably connected to a fuel delivery assembly M. The assembly l4 consists of conventional incidental parts comprising a nozzle, strainer, and nozzle body or adapter, and will not be described herein. It three-point supporting spider l5 adjustably affixed to the oil line [3 bymeans of a set screw 22 is positioned Within the dividing tube l to maintain axial alignment of the fuel delivery assembly M with respect to the nose piece 3. A further purpose of said spider is to provide a suitable supporting means for the attachment and. relational spacing of the ignition electrodes 1 6 which are held thereto by clamps 42. In slidable bearing on the oil line l3 and positioned towards the fan side of the dividing tube 1 is a disc I! which is mounted on a sleeve I8 which has its end flared outwardly to contact and control the movement of the disc H. The disc [1 is provided with holes. for the clearance of theprojecting electrodes l6 which act to prevent the rota! tion of said disc ll. The sleeve I 8 may be controlled in its movements by various mechanisms but inthe drawings is provided with a split clamp 23 having on the underside a suitable projection 24 to receive in pivotable connection thereto a motion transmitting link 25. Suitably spaced and clamped to the oil line l3 and in the direction approaching the fan is a supporting member 26 extending horizontally and perpendicular to the axis of said oil line. Attached to the outer end of said supporting member and extending downwardly is a projection 21 to receive and retain in pivotal attachment a bell lever 23. Said bell lever has one arm 29 extending preferably parallel to the oil line l3. The arm 29 is so shaped and proportioned with a shoulder 32 as to be manually actuated through a pressure contact of an adjusting screw 30 located through the fan housing I. The bell lever 28 is preferably tensioned by a spring 3| attached to the supporting member 26. The link 25 transfers longitudinal motion from the bell lever 28 to the sleeve l8 and disc IT. The blast tube 2 is preferably attached to the fan housing I by means of screws 33. The oil line [3 is provided with the conventional fittings 34 for connecting it to the conventional fuel oil source.

The dividing tube 1, is preferably provided with a fitting 35 having a dove tailed slot 36' for slidably positioning on the supporting bracket 6 which is formed to suit. The fitting 35 not only supports the dividing tube 1 but also allows it to be adjusted backwardly and forwardly in relation to the assembly 14 to suit the firing conditions required.

The motor, oil filters, transformers, pumps and other equipment not specifically mentioned are of the conventional types and do not form a part of this invention.

In operation, an oil burner of the type described would be provided with a fuel delivery assembly Id of predetermined capacity, the fuel thereto being supplied at constant. pressure. A nose piece 3, having an orifice 4 of suitable size to suit said oil nozzle would be attached to the blast tube 2. The air from the burner fan withoutrecourse to any other adjustment will be delivered through the orifice 4 in essentially the right amount for the particular firing rate. The relationship of the air register 9 and the orifice 4 provide the pattern of the issuing air stream which in turn controls to a large degree the resulting flame shape. Movement of the disc I! to or from the inner end 36 of the dividing tube 1 by means of suitable controlling means preferably such as has been described, acts as a valve. Said valve action controlling a small portion of the air and admitting same as a jet into the vortex of the air chamber formed in the space between the air register 9 and nose piece 3. By proportional relationship of the bell lever arms and lead or pitch of the adjusting screw 30 in contact therewith very close control of the valve disc I! is obtained even with the burner in operation. The approximate opening of this valve disc I l for the various firing rates may be predetermined to such a degree that settings may be made by reference to a, printed table and final nice adjustment can then be made through the fan air inlet control, using a gas analyser for reference if desired. One outstanding result in the use ofthis device has been found to be that even when the burner has been adjusted by one having little experience in the art and without the aid of a gas analyzing apparatus the results are generally far superior to the best adjustment obtainable on many burners of prior design.

While but one general form of the invention is shown in the drawings and described in the specifications, it is not desired to limit this application for patent to this particular form or in any other way otherwise than limited by the scope thereof, as it is appreciated that other forms of construction could be made that would use the same principles and come within the scope of the appended claims.

Having thus described the invention, what is claimed is:

1. In a burner the combination comprising a blast tube, means for supplying air to said blast tube, a conduit in fiow communication with a fuel supply and passing through said blast tube, a fuel nozzle positioned on the burner end of said conduit, a spider slidably positioned on said conduit within said blast tube, a supporting bracket attached to the internal portion of said blast tube, a dividing tube slidably positioned on said supporting bracket and spider, an air register positioned on the firing end of said dividing tube and shiftable for adjustment relative to said blast tube, a sleeve member mounted on said conduit, a disc mounted on said sleeve, and means adjustably positioning said disc in relation to the end of the dividing tube towards the fan housing for separating a portion of the air supply from the blast tube to create a stabilizing air current through said dividing tube.

2. In a burner the combination comprising a blast tube, means for supplying air to said blast tube, a conduit in flow communication with a fuel supply means and passing through said blast tube, a fuel nozzle attached to the burner end of said conduit, a spider positioned on said conduit, a supporting bracket attached to the internal portion of said blast tube, a dividing tube positioned on said supporting bracket and spider within said blast tube, means attached to the firing end of said dividing tube for dispersing the air from the blast tube, and shiftable for adjustment relative to said blast tube and an adjustable means for controlling the admission of a stabilizing air stream through said dividing tube.

3. In a burner the combination comprising a blast tube, means for supplying air to said blast tube, a conduit in flow communication with a fuel supply means and passing through said blast tube, a fuel nozzle attached to the burner end of said conduit, a spider positioned on said conduit, a supporting bracket attached to the internal portion of said blast tube, a dividing tube positioned on said supporting bracket and spider within said blast tube, means attached to the firing end of said dividing tube for dispersing the air from the blast tube, and shiftable for adjustment relative to said blast tube and adjustable means for controlling the admission of a stabilizing air stream through said dividing tube, a nose piece for attachment to the fire end of said blast tube.

4. In a burner the combination comprising a blast tube, means for supplying air to said blast tube, a conduit in flow communication with a fuel supply means and passing through said blast tube, a fuel nozzle attached to the burner end of said conduit, a spider positioned on said conduit, a supporting bracket attached to the internal portion of said blast tube, a dividing tube positioned on said supporting bracket and spider within said blast tube, means attached to the firing end of said dividing tube, for dispersing the air from the blast tube and shiftable for adjustment relative to said blast tube, an adjustable means for controlling the admission of a stabilizing air stream through said dividing tube, a nose piece for attachment to the fire end of said blast tube, said nose piece having an orifice in its end portion.

5. In a burner the combination comprising a blast tube, means for supplying air to said blast tube, a conduit in flow communication with a fuel supply means and passing through said blast tube, a fuel nozzle attached to the burner end of said conduit, a spider positioned on said conduit, a supporting bracket attached to the internal portion of said blast tube, a dividing tube positioned on said supporting bracket and spider Within said blast tube, means attached to the firing end of said dividing tube for dispersing the air from the blast tube, and shiftable for adjustment relative to said blast tube, an adjustable means for controlling the admission of a stabilizing air stream through said dividing tube, a nose piece for attachment to the fire end of said blast tube, said nose piece having an orifice in its end proportioned to suit the size of the fuel nozzle used.

6. In a fluid fuel burner, the combination with a fuel nozzle adapted to deliver a spray of fuel, a dividing tube positioned over the fuel nozzle but spaced therefrom, a blast tube positioned in spaced relationship over said dividing tube to create an air passage therebetween, said dividing tube being slidably mounted along said blast tube, air deflecting means attached to said dividing tube and slidably positioned in said blast tube for directing an air stream through the burner end of said blast tube, and means for providing a stabilizing air stream that will pass through said dividing tube and over the said fuel nozzle to position the point of flame propagation in said burner.

. RICHARD E. NEST.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,640,729 Scott Aug. 30, 1927 1,706,316 Norton et al Mar. 19, 1929 1,719,090 Stillman July 2, 1929 1,777,141 Howden Sept. 30, 1930 2,120,387 Bargeboer June 14, 1938 2,163,915 Reif et al. June 27, 1939 2,221,519 Jones et a1 Nov. 12, 1940 2,262,525 De Lancey Nov. 11, 1941 2,393,897 Glendenning Jan. 29, 1946

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