US2303925A - Oil burner - Google Patents

Description

Dec, 1, 1942. l A. J. FISHER 2,303,925

OIL BURNER Filed March 6, 1939 3 Sheets-Sheet 1 NoRs wJ. FwHliR Dec. -1, 1942.

A. J. FISHER OIL BURNER Filed March 6, 1939 5 sheet -sheet 2 IIIWW Ill/1%);

ANDRIEQV J. F\SHEZR I Dec. 1, 1942. M. FQISHER v 2,303,925

OIL BURNER Filed March 6, 1939 3 Sheets-Sheet 3 ANDREW J. Fusm-zR 'allel by means of an oil pressure regulator.

Patented Dec. 1, 1942 OIL BURNER Andrew J. Fisher, Baltimore County, Md., assignor to The C. M. Kemp Manufacturing Company, a corporation of Maryland Application March 6, 1939, Serial No. 260,032

9 Claims.

This invention relates to an oil burner for industrial purposes, and it has particular reference to an automatic air-adjusting burner suited for indirect firing, such as for galvanizing pots, drying ovens, pot annealing, and the like, and it is adapted to be equipped with a burner discharging either a long or short flame depending upon the size and shape of the combustion space. The long flame type of burner is particularly suited for recirculating furnace gases. high and its flame contracted.

The burner is of such simplicity in construction and manufacture that it will ordinarily not get out of order through long periods of use. It is designed to be adjustable to the furnace wall in the exact center of the opening provided, and it is also withdrawable therefrom for cleaning, or when not in use, or for changing the burners. Ordinarily about 50% of the air required for combustion is inspirated through the refractory tile 9 by the velocity of the air and oil stream. Means are provided for controlling the amount of this induced air. In the burner of this invention the bon. The burner is designed for mechanical atomization which allows the flow of oil to be controlled by pressure, and this in turn allows for the control of a plurality of burners in par- The use of oil pressure makes certain precision control arrangements practical, which would not otherwise 'be posssible of attainment, by controlling the flow of oil by means of valves.

Other advantages of the burner will be apparent from the following description, and the accompanying drawings forming a part hereof, and

in which similar numerals refer to similar parts throughout the several views:

Figure 1 is a partial vertical cross-sectional view of the short flame burner showing the automatic air control. Figure 2' is'a vertical view of Figure 4 Figure 6' is a sectional view on line 66 of Figure I 5. Figure 7 is an end view of the burner shown in Figure 5.

The furnace I is shown having an opening 2 1n the refractory tile 3, and coaxial with this open-.

Its velocity is attachments of double joint elbow 5, allow the burner to be placed in the exact center of the opening 2. The refractories of the furnace expanddiiferently from the steel framing of the furnace, and make necessary. exact adjustments or the burner to maintain this accurate alignment. The valve It] is turned to open position when the burner is in use, and it is closed when the burner is shut off. The sliding collar II on burner 4 is adjustable over the opening 2 to regulate-the air inspirated into the opening 2 by the air and oil-stream.

The burner proper comprises the: air entry pipe I2 which, at its discharge end, is constricted. as shown at l3, and this-construction tends to converge the air in its discharge to a point just beyond the end of the burner. Coaxial with this pipe I2 a shielding tube I4 carries the oil tube 55. The oil tube I5 screws into enlarged sleeve I6 forming part of the oil discharge head, and which is guided in shielding tube I4 by webs I1,

and webs I8 maintain the coaxial relation of tube 7 54 in pipe I2. Screw I9 in tube I4 slides in groove in to. prevent relative rotation of the sleeve I6 on tube I5. Sleeve I6 may have thereon an oil discharge nozzle for short flames indicated at 2| or one for long flames indicated at 22. This nozzle in one longitudinal position substantially closes theair discharge from the end of pipe I2, but upon the retraction of the nozzle a larger amount of air is discharged.

The burner is usually designed for the use of air at a comparatively low pressure, and oil at a comparatively high pressure, which is preferably heated to approximately 180 to 225 F. The amount of air discharged through constricted opening I3 of pipe I2 is regulated by the oil pressure. The shielding tube I4, which prevents the cold air from striking the oil tube I5, has at one end an enlarged portion 23 fitting tightly upon the enlarged portion of air conductor 8 and. I2 and forming one side of the chamber 24. The other side of this chamber 2-4 is the diaphragm 2'5 firmly attached centrally to oil tube I5 by means of collar 26, washer 21 and nut 28. Collar 26 has therein radial openings 29 connecting with similar openings 30 in tube I5. Washer and packing 3| allow longitudinal movement of tube I in tube 4 without appreciable loss of pressure. Tube I5 is held in a position to substantially close the air discharge outlet at constricted opening I3 by means of spring 32 fitting in cover 33 for the diaphragm 25, the whole assembly being held tightly in place on air pipes 8 and I2 by bolts 34. It will be apparent that as the pressure of the oil discharging in the chamber 24 increases, the diaphragm will be pushed back against the spring 32, and the nozzles 2| or 22 will be drawn backward, and the amount of air discharged from pipe l2 will thereby be increased precisely in proportion to the increase in oil pressure, and consequently the oil discharged.

The short flame nozzle shown in Figures 1, 3 and 4 has an antistream line outer section 35, and

. it is screwed into sleeve I6 by means of wrench openings 36. The nozzle has a cylindrical center opening 37 stopping short of the end of the nozzle, as shown at 38, and in this end opening is a small hardened discharge nozzle 39 having a conical opening therethrough. Fitting in the cylindrical opening 3'! is a square block 38, the edges of which are guided by the cylindrical opening. The end of this block toward the nozzle 39 has a cylindrical portion 40 thereon which has four slots 4| entering from its sides and which approach the center of the discharge nozzle 39 tangential to the large end of the conical opening through it, as shown in Figure 4. This end of the block 38' is held tightly against the discharge nozzle 39 by means of spring 42 fitting against the shoulder of the small oil opening 43 in sleeve I6. By means of this structure the oil enters from pipe |5, passing through opening 43 at a comparatively high pressure, and strikes the blunt end of block 38' which allows it to pass along the four sides of the block 38 down to the cylindrical portion 40 where it enters the tangential slots 4| from which it obtains a rapid spiral motion, and being contracted by the conical hardened member 39, and discharges in atomized form from the end of the nozzle. When the flow of air passes the conical nozzle 2| a low pressure area is created in front of th nozzle which creates in turn a flow of air toward the center of the nozzle from whence it radiates out to the main air stream. This back-drafting of the nozzle spreads the mechanical oil atomization from a cone of about 60 to on of about 180", the diameter of which is the same as the diameter of the nozzle. This creates a much finer degree of atomization than is otherwise obtainable by a straight mechanical atomizer and makes the oil burn in a short bushy flame.

In the long flame form of nozzle the sleeve l6,

' at its discharge end, has an outwardly extending cup formation 42, into which may be screwed primary air nozzle 43' by means of wrench holes 44. Oil discharge nozzle 45 is screwed into the sleeve l5 and between the two is placed a hardened fiow contracting member 46 beyond which the opening 4'! in the oil discharge nozzle 45 is enlarged. In this nozzle 45 is a pin 48 passing diametrically across the opening 47 and immediately in front of the constricted opening in member 46. The oil passing through this constricted opening at high pressure has that pressure suddenly released, and at high temperature this sudden release causes the oil to foam. The degree of foaming of the oil is determined by its temperature,

pressure, and viscosity. The striking of the pin deflects the oil stream and slows it to a uniform velocity in the opening 41. Axial openings 49 in cup-shape member 42' allow the passage of air from air pipe I2 through the circular opening in primary air discharge nozzle 43 and around the atomized oil from th oil discharge nozzle 45. This primary air opening is small. Its purpose is to carry the oil foam through the burner tile and into the furnace when the secondary air stream coming between constricted opening |3 in the air pipe l2 and th primary air nozzle 43', is shut off. This provides for a greater degree of turndown than is possible without the use of primary air. The secondary air opening is designed to furnish the greater percentag of air. Its shape is such that the air stream converges around the oil foam and primary air to form a condensed mixture which makes the oil burn in a long flame.

It should be understood that various changes in form, proportions, and minor details of construction may be resorted to within the scope of the appended claims.

Having thus described the invention, what is desired to be secured by Letters Patent, is:

1. An oil burner comprising an air pipe having a constricted discharge opening, an oil tube for the passage of oil therethrough under pressure and beinglongitudinally movable in said air pipe and arranged coaxially therewith and having thereon a discharge head closely fitting said constricted opening in one position and being movable to and from the opening, whereby the relative longitudinal position of said pipe and tube determines the rate of air discharge, a tube between said air pipe and oil tube to shield said oil tube from the air in said air pipe and hav ing guides therein adjacent the discharge end of said air pipe, the discharg head on said oil tube extending rearwardly in said guides, oil atomizing means in said head discharging centrally of the air stream, and means for automatically moving said pipe and oil tube relatively longitudinally upon variations in pressure of the oil passing through said oil tube.

2. An oil burner comprising an air pip having a constricted discharge opening, an oil tube for the passage of oil therethrough under pressure and being longitudinally movable in said air pipe and arranged coaxially therewith and having thereon a discharge head fitting closely said constricted opening in one position and being movable from the opening whereby the relative longitudinal position of said pipe and tube determines the rate of air discharge, oil atomizing means in said head discharging centrallyof the air stream and means for automatically moving said pipe and tube relatively longitudinally upon variations in pressure of the oil passing through said tube.

' by variations in pressure of the oil passing through said tube connecting said pipe and tube to move them relatively longitudinally.

4. An oil burner comprising an air pipe having a constricted discharge opening, an oil tube for the passage of oil therethrough under pressure longitudinally movable in said air pipe and arranged coaxially therewith and having a discharge end in one position fitting closely said constricted opening, whereby the relative longitudinal position of said pipe and tube determines the rate of air discharge and means operated by variations in pressure of the oil passing through said oil tube, connecting said pipe and tube to move them relatively longitudinally.

5. An oil burner comprising an air pipe, an oil tube for the passage of oil therethrough under pressure longitudinally movable in said air pipe, said pipe having an air discharge end and said tube having an oil discharge head thereon closely fitting said pipe discharge end in one longitudinal position to control the discharge of air from said air pipe at a rate determined by the relative longitudinal positions of said pipe and tube, constantly operating means tending to move said pipe and tube relative to each other and means operated by variations in pressure of oil passing through said tube to move said pipe and tube in the opposite relative direction.

6. An oil burner comprising an air pipe, an oil tube longitudinally movable therein arranged coaxially therewith, said pipe having an air discharge end and said tube having an oil discharge head thereon closely fitting said pipe discharge end in one longitudinal position to discharge air from said air pipe at a rate determined by the relative longitudinal positions of said pipe and tube, means constantly tending to move said pipe and tube relative to each other, a diaphragm centrally attached to said tube and perimetrically to said pipe, a closed chamber member attached to said pipe and surrounding said tube, said diaphragm forming one wall of the chamber, the wall of said tube having openings leading into said chamber, whereby changes in the pressure of the oil passing through said tube move the diaphragm in opposition to the means tending to move said pipe and tube and thereby vary the rate of air discharge.

7. An oil burner comprising an air pipe having a constricted discharge opening, an oil tube therein coaxial therewith, a tube between said air pipe and oil tube to shield said oil tube from the air in said air pipe, said shield tube having guides thereon adjacent the discharge end of and supported from said air pipe, a discharge head on said oil tube extending through and supported by said guides, and means including said head to regulate the discharge of air around the oil discharged from said head.

8. An oil burner comprising an air pipe having a constricted discharge opening, an oil tube therein coaxial therewith, a tube between said air pipe and oil tube to shield said oil tube from the air in said air pipe, said shield tube having guides thereon adjacent the discharge end of and being supported from said air pipe, a discharge head on said oil tube extending through and supported by said guides, said oil tube and head being longitudinally adjustable in said guides, and means including said head to regulate thedischarge of air around the oil discharged from said head, the rate of the discharge being varied by changing the relative position of said head and opening.

9. An oil burner comprising an air pipe having a constricted discharge opening at one end thereof, an oil tube therein coaxial therewith having an enlarged head in one position fitting closely said constricted opening at the discharge end thereof, a shielding tube between said pipe and oil tube having guides thereon supported by said air pipe and on which said oil tube is longitudinally adjustable to vary the rate of air discharge between the constricted opening and en-v larged head, said head separating the oil and air until both have left the burner.

ANDREW J. FISHER.

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