US3053462A

US3053462A - Constant capacity nozzle

Info

Publication number: US3053462A
Application number: US129876A
Authority: US
Inventors: Ferdinand G Schloz
Original assignee: MONARCH Manufacturing WORKS Inc
Current assignee: MONARCH Manufacturing WORKS Inc
Priority date: 1961-08-07
Filing date: 1961-08-07
Publication date: 1962-09-11
Anticipated expiration: 1979-09-11

Description

F. G. SCHLOZ 3,053,462

Sept. 11, 1962 CONSTANT CAPACITY NOZZLE Filed Aug. 7, 1961 l 44 I 1 10 l 3 '1 INVENTOR. immw/d die/71027,

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This application is a continuation-in-part of my patent application, Serial No. 87,595, filed February 7, 1961, entitled Constant Capacity Nozzle, now abandoned.

This invention relates to fluid spray nozzles. By means of my invention, substantially constant flow rates are obtained regardless of changes in fluid viscosity.

While the nozzle of the present invention is principally used for fuel oil, it may be used to handle other fluids, such as gasoline, waxes, wax emulsions, insecticides, vegetable oils, hot transformer oils, etc. Thus, while the new nozzle is particularly adapted for use on high-pressure domestic oil burners, it may also have other applications, such as in airplane heaters, jet engines, diesel engines, starting heaters, crop dryers, crop Sprayers, incubators, etc.

While, as just indicated, the nozzle of the present invention has other applications, it will be convenient to describe the new nozzle in its application as a nozzle for a high-pressure gun-type domestic oil burner.

Domestic gun-type oil burners ordinarily operate at a fixed pressure of from 75 to 200 psi, usually 100 psi. However, the capacity of the conventional prior-art nozzle, that is, the rate of discharge of the fuel oil from the orifice of the nozzle, varies with the 'viscosity of the fuel oil, the higher the viscosity, the greater being the nozzle capacity or rate of discharge.

Stated another way, the conventional prior-art nozzle for a domestic oil burner is characterized by an inability to discharge oil at the same rate over the range of temperatures to which the burner is subjected during normal operation, this inability being a result of the fact that the viscosity of the oil changes with temperature. Thus, in \the usual thermostatically controlled domestic oil burner system, where the burner is repeatedly being turned on and off under the control of the thermostat, the rate at which the oil is discharged from the orifice of the nozzle at start-up, when the burner and fire box are relatively cold, is appreciably higher than the rate at which the oil is discharged after the burner and fire box become hot.

The fact that the rate of discharge is higher when the oil is cold and of higher viscosity may seem to be the reverse of that which would be expected, but is explained by the fact that, in the conventional nozzle of a domestic oil burner, the oil is swirled about in a swirl chamber located inside the tip shell and is delivered from the discharge orifice of the nozzle in a swirling spinning manner, forming a cone-shaped spray pattern. The fuel oil when cold and of higher viscosity swirls in the swirl chamber at a substantially slower swirl rate than does the oil when hot and of substantially lower viscosity, and it has been established that the rate of discharge from the orifice of the nozzle is inversely related to the swirl rate, the faster the oil is swirling in the swirl chamber, the slower the rate of discharge from the orifice.

The fan and airrnixing equipment of the conventional domestic oil burner are designed to deliver air at a substantially fixed rate. The combustion air and draft conditions are ordinarily adjusted for optimum firing results after the fire box and burner have war-med up. Thus, it will be seen that at start-up, when the fire box and burner are relatively cold, and the oil being of higher viscosity is swirling at a slower rate and discharging at a faster rate, the fixed quantity of air provided by the air 3,053,462 Patented Sept. 11, 1962 mixing equipment is less than that required for optimum combustion, and this insufficiently of combustion air on start-up causes a smoky, sooty condition which is objectionable and which is avoided by the improved nozzle of the present invention.

The broad object of the present invention then is to provide a fluid spray nozzle capable of discharging fluid at a substantially constant rate irrespective of the viscosity of the fluid, within the operating range of the device.

It is another object of the present invention to provide a nozzle for a fuel oil burner which discharges fuel oil at a substantially constant rate irrespective of changes in the viscosity of the fuel oil due to variations in the operating temperature, or due to any other cause, such as varia' tions in the grade of the fuel oil.

A more specific object is to provide a constant capacity nozzle for a domestic oil burner capable of discharging fuel oil at a substantially constant rate despite variations in the viscosity of the oil.

Another object of the invention is to provide a spray nozzle which will discharge fluid at a substantially constant spray angle irrespective of the viscosity of the fluid.

A more specific object is to provide a spray nozzle for a domestic oil burner which will discharge fuel oil at a substantially constant rate and at a substantially constant spray angle irrespective of variations in the viscosity of the fuel oil.

The above and other objects and advantages of the present invention are accomplished by a nozzle construction in which the swirl-imparting member or disk carries the swirl slots well into the swirl chamber, with the swirl slots so positioned that their inner edges are outside the projected diameter of the orifice by a small dimension. This construction, which will be better understood after the detailed description which follows is read, has been found to produce a stabilized rate of flow, the nozzle discharging fluid at substantially the same rate irrespective of its viscosity.

The invention will be more clearly understood from a consideration of the following detailed description of a preferred embodiment illustrated in the drawing, in which:

FIG. 1 is a side elevational view, mainly in section, of one formv of the improved nozzle;

FIG. 2 is a top or end view, partly in section, of the improved nozzle of FIG. 1;

FIG. 3 is an enlarged view, partly in section, of the end portion of the nozzle of FIG. 1 showing the discharge orifice, the swirl chamber, and the swirl disk having swirl slots entering into the swirl chamber; and

FIG. 4 is a view in section along the line IV-IV of FIG. 3 looking in the direction of the arrows.

In describing the preferred embodiment of the invention illustrated in the drawing, specific terminology has been resorted to for the sake of clarity. However, it is not my intention to be limited to the specific terms 50 selected, and it is to be understood that each specific term includes all technical equivalents which operate in a similar manner to accomplish a similar purpose.

Referring now to the drawing, the nozzle illustrated includes a conventional hollow tip shell 10 and a conventional hollow adapter 12. The tip shell 10 may preferably be of stainless steel while adapter 12 may preferably be of brass.

The tip shell 19 comprises an upper rounded portion 14, a hexagonal center portion 16, and a lower externally threaded portion 18. Rounded portion 14 is flattened at the top and is provided with the usual small cylindrical orifice 20 which connects the hollow interior of the tip shell 10 to the exterior of the shell and functions as the dis charge orifice for the fuel oil or other fluid. The center portion 16 has a hexagonal exterior to facilitate tightening or loosening of the tip shell by a tool. Portion 18 is threaded externally for receiving the adapter 12 and is threaded internally for receiving a lock-nut 22 and a strainer support 26.

Adapter 12 has an upper larger bore and a lower smaller bore, both bores being threaded internally. The upper portion of the threaded upper bore is adapted to engage with the externally-threaded portion 18 of the tip shell 10. The lower portion of the upper larger bore of adapter 12 is adapted to receive the usual hollow cylindrical strainer screen 24 suitably supported by the strainer support 26 containing feed slots 26a. Strainer support 26 is provided at its upper end with external threads for engagement with the lower internal threads of the portion 18 of tip shell 10, thereby providing a space or passage between the inner surface of the lower portion of the upper bore and the cylindrical strainer screen 24. The lower end of strainer support 26 is solid.

The smaller lower bore of adapter 12 is for receiving the fuel-supply pipe which connects the nozzle to the fuel supply.

As seen in FIGS. 1 and 3, the hollow interior of the tip shell 10, which is conventional, is characterized by a first frusto-conical swirl chamber 30 just below the cylindrical axial discharge orifice 10, a second frusto-conical diskseating chamber 32 below the swirl chamber 30, and a cylindrical chamber 34 below the second frusto-conical chamber 32. The slope of the wall of the swirl chamber 30 is substantially steeper than that of the wall of the diskseating chamber 32. In the absence of the swirl disk 40, described below, the lower limit of swirl chamber 30 would be an imaginary horizontal plane which coincides with the plane of the upper limit of chamber 32, this plane being identified in FIG. 3 by the dotted line 36. However, when the swirl disk 40 is in place and seated, as is the case when the nozzle is assembled for use, the floor or bottom of the swirl chamber 30 also has a frusto-conical configuration which is different in shape from the frusto-conical top portion of the swirl chamber. It will be understood that the frusto-conical floor or bottom portion of swirl chamber 30 is formed by the upper portion of the swirl disk 40.

Swirl disk 40 is a solid, frusto-conical disk, preferably of stainless steel, which is fitted into the top of a hollow cylindrical holder 42, which may be of brass. Holder 42 is provided near its lower end with a pair of opposed holes 44, 46 which extend completely through the wall of the holder. The outside diameter of holder 42 is smaller than the inside diameter of chamber 34, thus providing an annular space or passage for the oil or other fluid which fiows out through the holes 44, 46, as will be described.

Swirl disk 40 and holder 42 are supported by the locknut 22 previously mentioned. Lock-nut 22 is T-shaped, its larger upper portion being externally threaded for engagement with the internal threads of portion 18 of the tip shell 10. The smaller lower portion of lock-nut 22 is provided with a slot for facilitating turning by a tool. Lock-nut 22 is provided with an axial bore which extends completely therethrough thereby providing communication for fluid flow between the interior of the strainer support 26 and the hollow interior of the disk holder 42.

Described in greater detail, swirl disk 40 has a solid cylindrical lower portion which fits into and is received by the hollow upper portion of the holder 42. The upper portion of swirl disk 40 is solid and frusto-conical, the base portion thereof being of slightly larger diameter than the depending cylindrical portion which fits into the holder 42. The conical portion slopes upwardly at an angle equal to that of the slope of inner wall of frustoconical chamber 32 so that when the lock-nut 22 is turned in a direction to move the lock-nut upward in the tip shell 10, the surface of the frusto-eonical portion of the swirl disk 40 seats against, i.e., makes wide band contact with, the wall of chamber 32.

The surface of the frusto-conical portion of swirl disk 40 is provided with one or more, usually four, straight swirl slots which are milled or otherwise cut in the frustoconical surface and which extend from the lower edge of the frusto-conical portion to the upper edge. Four such swirl slots are shown in the drawing identified by the

reference numerals

48a, 48b, 48c and 48d.

The location of the swirl slots in the sloping surface of the frusto-conical portion of disk 40 is such that when the disk 4% is viewed from the top or end, as in FIGS. 2 and 4, the swirl slots appear to be at right angles to each other with the inner edge of each slot (i.e. the edge nearer to the projected diameter of orifice 20) being close to but outside of the projected diameter of orifice 20. -A specific example of this structural arrangement is illustrated in FIGS. 3 and 4 where the orifice 29 (FIG. 3) is shown as having a diameter of .011 inch while the distance between the projected inner edges of opposite slots 48!; and 48d is shown as being .013 inch. Thus, the inner edge of each of the slots 48!) and 43d is outside of the projected diameter of orifice 20 (illustrated by the dot-and-dash circle 20a in FIG. 4) by .001 inch. This last small dimension (.001") is not shown to scale in the drawing in order to show clearly that the inner edges of the slots are outside of the projected diameter of the orifice.

The same dimensions shown for

slots

48b and 48d also apply to the other pair of opposite slots 48a and 48c.

Stated more generally, the

swirl slots

48a, 48b, 48c and 48d enter the swirl chamber 30 on a diameter slightly larger than the diameter of the projected orifice, where the diameter of entry of the slots is defined as the distance between inner edges of opposite slots, .013 in the illustrated example. Thus, in the example illustrated, the slots enter the swirl chamber 30 on a diameter of .013" as compared with an orifice diameter of .011.

It is to be noted that opposing slots, such as 48a, 480, are not axially aligned, but are off-set from each other. Thus, the slots 48 are trangential to the swirl chamber 30. When the disk 40 is viewed from the side in elevation as in FIGS. 1 and 3, the four

swirl slots

48a, 48b, 48c and 48d are of course, seen to slope upwardly and inwardly, following the slope of the frustoconical portion of swirl disk 40.

It is also to be noted that in the constant capacity nozzle of the present invention the frusto-conical portion of the swirl disk 40 is sized and shaped to carry the swirl slots above the lower limit 36 of the wall of the swirl chamber 30. Stated another way, the swirl slots are carried above the uppermost line of contact between the wall of the chamber 32 and the wall of the swirl disk 40, and thus may be said to be carried well into the swirl chamber 36.

In operation, fuel oil from the source of supply is fed into the nozzle by way of the lower bore of the adapter 12 in the direction of the arrow in FIG. 1. "The fuel oil is fed at substantially fixed pressure, in the range of from 75 to 200 psi. ordinarily about psi, and flows through the lower bore of adapter 12 into the annular space between the strainer 24 and the wall of the larger bore of the adapter 12, then through the screen of strainer 24 in the direction from outside the strainer screen through the feed slots 26a to the interior of the strainer support 26, up through the bore of the lock-nut 22 into the bore of disk holder 42, out through holes 44, 46 in the disk holder 42, up through the space between the outer wall of the disk holder 42 and the inner surface of the cylindrical chamber 34, up through the

swirl slots

48a, 48b, 48c, and 48d into the swirl chamber 30, and out through discharge orifice 20. As the fuel oil (or other fluid) is forced under pressure out of the

swirl slots

48a, 48b, 43c, and 48d and into the frusto-conical swirl chamber 30, the oil is caused, by the tangential positions of the swirl slots relative to the swirl chamber 30, to swirl about within the chamber 30. The oil continues to swirl as it passes through the orifice 20', and is discharged therefrom in a spinning swirling atomized spray of cone configuration.

While the reasons are not fully understood, when the swirl slots are carried well into the swirl chamber on a diameter slightly larger than that of the projected orifice, .013 inch versus .011 inch in the illustrated example, the rate at which the fuel oil (or other fluid) swirls about within the swirl chamber 30 apparently becomes independent of the viscosity of the oil. In any event, when this construction is used, the nozzle becomes characterized by the ability to discharge oil (or other fluid) at a constant rate irrespective of the viscosity of the fluid, within the range of operation of the nozzle. In other words, when the construction of the nozzle is changed from one in which the swirl ducts terminate at or below the lowermost limit of the wall of the swirl chamber to one in which the swirl ducts extend well into the swirl chamber, on a diameter slightly larger than that of the orifice, as described above, the nozzle becomes converted from one whose capacity varies with viscosity to one of substantially constant capacity over the range of viscosities for which the nozzle is intended to operate.

The following is an illustration of the improvement afforded by the new nozzle of the present invention. Tests have shown that the capacity (i.e. the rate of fluid discharge) of the prior art nozzle will vary as much as 20 to 25 percent between the extremes of cold oil at 5060 F. and hot oil at about 250 F., these being the temperature ranges ordinarily encountered in domestic oil burner operation. "Stated in terms of kinematic viscosity, this represents a variation of from about 4.3 centistokes when cold, to about 0.85 centistokes when hot.

Whereas the prior-art nozzles vary in capacity by as much as 20-25 percent during operation between the above stated extremes of temperature and viscosity, the nozzle of the present invention has been found to vary by only about 2 percent. Thus, the improved nozzle may be said to be a nozzle of substantially constant capacity over the expected operating range of temperatures and viscosities. As a result, the objectionable sooting which characterizes the prior-art burner at start-up is avoided.

In addition to being characterized by the ability to discharge fuel oil or other fluid at a substantially constant capacity, the new nozzle produces cone sprays having spray angles which are substantially constant with varying viscosity of fuel oil or other fluid. This is also a highly desirable operating characteristic.

The exact relative dimensions or proportions of such things as size of orifice, size and shape of swirl chamber, size and shape of disk seat and disk-seat chamber, number and size of swirl slots, etc., will vary with desired nozzle capacity. The following is one specific example of nozzle dimensions which have been found to produce a constant capacity nozzle for #2 fuel oil having a rating of 1.00 gallon per hour (g.p.h.) at 100 p.s.i. The discharge orifice of 0.011". The swirl chamber has a frusto-conical top portion and a frusto-conical floor formed by the disk. The swirl chamber has a maximum diameter of 0.060" and an included angle of 84. The frusto-conical seat of the swirl disk has an included angle of 120, and four feed slots each 0.007" square. The feed slots enter the swirl chamber on a diameter of .013, as defined hereinbefore, the inner edges of opposite slots being .013" apart. Tests have shown that when a 1.00 g.p.h. nozzle having the above dimensions is used to discharge #2 fuel oil at 100 p.s.i. over a temperature variation from 50 F. to 250 F., which is equivalent to a viscosity variation of from 4.3 centistokes to .85 centistokes, the variation in rate of discharge is only 0.02 g.p.h., or about 2 percent. Using the same grade of oil and over the same range of temperatures, the capacities of prior art nozzles were 6 found to vary between 18.5 and 27.0 percent. On some sizes of the new nozzle, the variation in capacity is only 0.002 g.p.h. when the temperature is varied :firom 50 F. to 250 F.

While the preferred embodiment of this invention has been described in some detail, it will be obvious to one skilled in the art that various modifications may be made without departing from the invention as hereinafter claimed.

Having described my invention, I claim:

1. A fluid spr-ay nozzle comprising a tip shell having an orifice, an internal frusto-conical swirl chamber and an internal disk seating chamber, a frusto-conical swirl disk mounted internally and seated in said disk seating chamber and formed with one or more feed slots, said swirl chamber having a concave frusto-conical base portion when said disk is seated in said disk seating chamber, said feed slots entering said swirl chamber on a diameter just sufliciently larger than the projected diameter of said orifice to bring the projected inner edges of said feed slots outside said projected diameter of said orifice by a distance substantially less than the diameter of said orifice.

2. A fluid spray nozzle comprising a tip shell having an orifice, an internal frusto-conical swirl chamber and an internal disk seating chamber, a frusto-conical swirl disk mounted internally and seated in said disk seating chamber so as to extend substantially into the swirl chamber and formed with one or more feed slots, said swirl chamber being of frusto-conical shape at each end when said disk is seated in said disk seating chamber, said feed slots entering said swirl chamber on a diameter just sufliciently larger than the projected diameter of said orifice to bring the projected inner edges of said feed slots outside said projected diameter of said orifice by a distance substantially less than the diameter of said orifice.

3. A fluid spray nozzle comprising a tip shell having an orifice, an internal frusto-conical swirl chamber and an internal disk seating chamber, a frusto-conical swirl disk mounted internally and seated in said disk seating chamber so as to extend substantially into the swirl chamber and formed with a plurality of feed slots carried by said disk substantially within the swirl chamber, said swirl chamber having a dished frusto-conical base portion when said disk is seated in said disk seating chamber, said feed slots entering said swirl chamber on a diameter just sufliciently larger than the projected diameter of said orifice to bring the projected inner edges of the feed slots outside said projected diameter of said orifice by a distance substantially less than the diameter of said orifice.

4. A fluid spray nozzle comprising a tip shell having an orifice, an internal swirl chamber and an internal disk seating chamber, a swirl disk mounted internally and seated in said disk seating chamber so as to extend substantially into the f-rusto-conical swirl chamber and formed with one or more feed slots carried by said disk substantially within the swirl chamber, said swirl chamber formed by two adjacent non-congruent frusto-conical shapes when said swirl disk is seated in said disk seating chamber, said feed slots entering said swirl chamber on a diameter just sufficiently larger than the projected diameter of said orifice to bring the projected inner edges of the feed slots outside said projected diameter of said orifice by a distance substantially less than the diameter of said orifice.

5. A fluid spray nozzle comprising a tip shell having an orifice, an internal frusto-conical swirl chamber and an internal disk seating chamber, a frusto-conical swirl disk seated within said disk seating chamber and extending substantially int-o the swirl chamber but without contacting the wall of said swirl chamber, a plurality of feed slots in the surface of said disk, a portion of said feed slots extending into said swirl chamber without contact thereof, said swirl chamber being formed by two adjacent noncongruent frusto-conical shapes when said swirl disk is seated within said disk seating chamber, said feed slots entering said swirl chamber on a diameter just sufficiently larger than the projected diameter of said orifice to bring the projected inner edges of the feed slots outside said projected diameter of said orifice by a distance substantially less than the diameter of said orifice.

6. A fluid spray nozzle comprising a tip shell having an orifice, an internal swirl chamber and an internal disk seating chamber, a frusto-conical swirl disk mounted internally and seated in said disk seating chamber so as to extend substantially into the swirl chamber and formed with one or more feed slots carried by said disk substantially within the swirl chamber, said swirl chamber being of frusto-conical shape at each end when said swirl disk is seated in said disk seating chamber, said feed slots entering said swirl chamber on a diameter sufiiciently larger than the projected diameter of said orifice to bring the inner edges of the feed slots outside said projected diameter of said orifice by a distance substantially less than the diameter of said orifice.

7. A fluid spray nozzle comprising: a tip shell having an orifice, an internal swirl chamber and an internal diskseating chamber; a swirl disk seated in said disk-seating chamber and having at one end a frusto-conical portion extending into said swirl chamber, said swirl chamber having a frusto-conical shape with the small diameter end communicating with said orifice, said swirl chamber also having a frusto-conical floor formed by the frusto-conical portion of said swirl disk, said swirl disk having in the surface of its frusto-conical portion a plurality of swirl slots so positioned that said swirl slots enter said swirl chamber on a diameter sufliciently larger than the diameter of said orifice projected onto the face of said frusto conical portion of said swirl disk so that the inner edges of said slots are just outside said projected diameter of said orifice by a distance substantially less than the diameter of said orifice.

8. A fluid spray nozzle as claimed in claim 7 adapted for discharging #2 fuel oil at 1.00 gallon per hour (average) at 100 pounds per square inch, characterized in that said orifice has a diameter of .011 inch and in that said swirl slots are so located as to enter said swirl chamber on a diameter of .013 inch.

9. A fluid spray nozzle as claimed in claim 7 characterized in that said swirl slots enter said swirl chamber on a diameter just suificiently larger than the diameter of said orifice projected onto the face of said frusto-conical portion of said swirl disk so that the projected inner edges of said slots are outside said projected diameter of said orifice by a distance which is of the order of thirty percent or less of the diameter of said orifice.

References Cited in the file of this patent UNITED STATES PATENTS 1,896,744 Frick Feb. 7, 1933 1,982,228 Murphy Nov. 27, 1934 2,071,920 Czarnecki Feb. 23, 1937 FOREIGN PATENTS 20,199 Great Britain of 1891 UNITED STATES PATENT CERTIFICATE OF CORRECTION Patent No, 3,053,462 September 11, 1962 Ferdinand G. .Schloz It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 6, line 55 strike out "frust;conical" and insert same before "swirl disk", in line 53, same column 6.

Signed and sealed this 19th day of February 1968 (SEAL) Attest:

ESTON G, JOHNSON DAVID L. LADD Attesting Officer I Commissioner of Patents