US3409000A - System for heating large volumes of air - Google Patents

Description

N0V 5, 1968 c. H. BRADER ETAL. 3,409,000

SYSTEMAFOR HEATING LARGE VOLUMES OF AIR Filed Sept. 1.9, 1966 2 Sheets-Sheet l l N VEN TOR. afm H. SRA/DER 5y ART/wl? 5. 72H/1555 Nov. 5, 1968 c H. BRADER ETAL 3,409,000

SYSTEM FOR HEATING LARGE VOLUMES OF AIR Filed Sept. 19, 1966 2 sheets-sheet 2 M l L Q Q Q Qc Q e Q Q/QCi 44 Q Q W42 43 505-9 L O 562 54 y INVENTOR.

United States Patent O SYSTEM FOR HEATING LARGE VOLUMES OF AIR 'Carl H. Brader, Prosser, and Arthur E. Tanasse, Sunnyside, Wash., assignors to Redi-Fire Heating, Inc., .2l corporation of Washington i Filed Sept. 19, 1966, Ser. No. 580,251

7 Claims. (Cl. 126-595) ABSTRACT OF THE DISCLOSURE This invention relates to oil-fired systems for heating large volumes of air in the absence of a supply of forced air for effecting mixture of oil and air for burning. For example, the invention is applicable to orchard heating systems, systems for heating greenhouses, lor space heaters 'for use in heating construction site areas or large buildings in cold weather, where a supply of oil is or can b e made available under pressure, but where forced air is not sought to be utilized as it is, for example, in a domestic furnace burner. Domestic oil furnace burners utilize -an oil nozzle and a forced air nozzle in combination to provide an eflicient mixing of air and oil in a burnable mist. Another forced air circulation system is then utilized to distribute the heat from the burner to different areas of the home or building. The present invention is concerned with a heating unit utilizing neither of these auxiliary forced air elements, but utilizes only a special nozzle and convection as means for mixing air and oil to form a burnable mist, and utilizes convection and radiation to distribute the heat. While the invention is herein described in terms of preferred forms thereof various modifications and changes therein will be recognized within the scope of the principles involved.

Background and summary of the invention This invention provides an oil-fired convection-radiation heating device connectable to a source of oil under pressure. The device includes a flame-constraining heat radiant shroud having a vertical axis and side walls spaced from the axis to define a burner cavity. The side walls have air openings to admit air by convection caused by burning within said cavity. An oil mist generating nozzle adapted to be positioned at the bottom of the shroud includes means for coupling the nozzle to the source of oil under pressure and further includes an outer jacket having an oil exit orifice therein adapted' to direct oil upwardly into the burner cavity. The nozzle includes means within the jacket defining oil delivery channels which converge upwardly and are laterally offset to impart to the oil forced through them an upwardly spiraling motion with sufficient angular velocity tangential to the orifice upon exit therefrom to effect breakup of the oil into a mist of lighter-than-air droplets within the burner cavity. The mist is mixed with air entering the shroud through the various air inlet openings by convection when ignited.

Legs attached to the shroud are of length sufiicient to hold the bottom of the shroud above a .supporting surface, such as t-he ground. A bottom plate includes a centrally located opening and bracket means secured across the opening for positioning the nozzle therein while permitting entry of air by convection around the nozzle. The shroud is of frusto-conical shape with flame constraining upward convergence sufficient to maintain substantially complete combustion of the oil mist, or is cylindrical in shape and includes an annular bafiie at the top to achieve this end.

The outer jacket of the nozzle preferably forms an inner cavity having a cone-shaped roof terminating in the 3,409,000 Patented Nov. 5, 1968 oil exit orifice at its apex. A cylindrical insert member positioned axially within the cavity forms an annular cavity around the outside thereof within the jacket'The insert member includes a cane-shaped top surface of taper identical to that of the cone-shaped roof and having t-he oil delivery channels formed therein. The channels thus converge upwardly, and they are substantially symmetrically offset with respect to the orifice whereby to impart the aforementioned angular velocity to oil particles forced under pressure `from the annular cavity to the orifice.

While a heating device constructed according to the invention has a number of uses as suggested above, the principal use intended therefor is for the eating of orchards in the freezing season. Many different forms of so-called smudge pots have been devised for the purpose of protecting growing fruit from freezing weather by heating the air'in the orchard. Many of these have involved very cumbersome maintenance and fuel supply procedures. Beginning with the initial practice of simply building bonfires distributed among the trees, oil-burning pots were devised in which a pan of oil was simply ignited to burn in a connected stack which radiated some heat, but also exuded excessive amounts of black smoke. Hence the term smudge pots. The necessity for refilling the pots with oil periodically, the the delay and difiiculties in igniting them one by one in a large orchard led to the development of networks of oil supply lines laid either above or below ground and extending to the various burners located among the trees. The burners were still usually of the inefficient oil pan type wherein evaporation of the oil by heating from the burning above its surface was relied upon for mixing oil vapor with air.

Subsequently, many different forms of burners were devised to improve efficiency, some including a nozzle spraying the oil into the air or against a splash pan. Typical of such devices was that shown in the patent to Ruprecht, 1,571,969, issued Feb. 9, 1926 wherein the oil was squirted upwardly from a circular opening in an inverted cone-shaped pattern and against the sides of the burner. While the squirting of the oil in a relatively thin fan or film provided some improvement in burning efficiency, it left considerable room for improvement. Although such a device was referred to as atomizing the oil, it lacked means in the nozzle for breaking up the oil into lighter-than-air droplets to form a true mist which could be mixed uniformly with air drawn in by convection. Instead such a nozzle served primarily only to spray the oil into the air in large droplets and against splash pans or the sides of the burner, some of it being burned in the air and other portions being burned on the surfaces of the burner itself.

The present device is of this `general type, but provides a different, more efficient combination of nozzle and shroud. The nozzle design utilized is particularly chosen for its capability for breaking up the oil into a fine mist which, at least momentarily, is lighter than air, though after a time it would settle as droplets coalesce. Burning eliiciency is created by utilization of such a nozzle in combination with a shroud designed to admit outside air by convection, creating an oil-air mixture completely filling the shroud so that when ignited the entire shroud of volume greater than most previous smudge pot stacks is filled with liame, radiating heat and causing movement of heated air above and around the shroud as well.

AICC

Units according to the invention are well adapted-to utilization of either a buried pipeline network, or an aboveground pipe system, and the system contemplates utilization of oil supply means which includes a pressure pump developing from 30 to 400 pounds per square inch whereby in combination with the yaforementioned features the oil pressure is sufcient to break up the oil as it is emitted from the nozzle.

These and other features objects and advantages of the invention will become more apparent from the following detailed description of preferred forms thereof, taken in connection with the accompanying drawings.

Description FIGURE 1 is an isometric view of a preferred form of the invention, with a portion of the shroud cut away to reveal internal details and showing the same in combination with an underground oil line distribution system.

FIGURE 2 isa sectional side view of the heating device shown in FIGURE l.

FIGURE 3 is a side View of the nozzle utilized in the heating device lof FIGURE l, showing portions thereof in sections to reveal internal details.

FIGURE 4 is a sectional view taken downwardly at plane 4-4 of FIGURE 3, but showing the top of an internal member above that plane.

FIGURE 5 is an isometric view of a second embodiment of the invention with portions of the shroud cut away to reveal internal details, and illustrating its combination with an aboveground oil supply line.

FIGURE 6 is a sectional side view of the heating device shown in FIGURE 5.

In the embodiment shown in FIGURE l a cylindrical flame-constraining shroud 10 of galvanized steel or other suitable material is supported on three legs 12 of angleiron shape and of length suflicient to be embedded in the ground G to stabilize the burner against wind while holding the shroud .aboveground for entry of air beneath. The shroud includes a circular bottom plate 14 having a central air inlet opening 16 and an upwardly directed flange 18 around its circumference to which the cylindrical side wall of the shroud is welded or riveted. A circular top baille 20 having a central opening 22 and an upwardly directed circumferential flange 24 to which the cylindrical side wall of the shroud is secured, serves to constrain flames within the shroud for more complete combustion of the oil mist created within it as will be described. Bracket 26 riveted or welded to the bottom plate 14 at both ends extends across air inlet opening 16. Its central portion is spaced downwardly from the opening to permit entry of air and has a central hole 28 which positions within air inlet opening 16 the yoil mist generating nozzle 30 connected to an underground oil distribution line 32 by means of the upwardly extending neck 34.

Besides air inlet 16, the shroud further includes circumferential rows of inlet orifices 36 and 38 spaced uniformly around its side walls. The total area of .all such openings is roughly equal to that of exit opening 22 in top baille 20 to establish equilibrium between entry of fresh air and exit of burningg oil-air mixture.

The cylindrical shroud 10 is preferably about 18 inches from top to bottom and twelve inches in diameter, and the legs 12 support it a few inches above the ground to permit entry of air from beneath. The units are easily stacked, with the legs 12 of one unit fitting down the sides of the unit below, and they are of light-weight construction so as to be easily disributed in the field and picked up a the end of the season.

A second form of burner is illustrated in FIGURES 5 and 6 wherein the shroud 40 of galvanized steel or the like is of frustro-conical shape, about twenty-four inches high, ten inches in diameter at the bottom and eight inches in diameter at the top. Circumferential rows of orifices 42, 44, 46 are formed therein by punches forming downwardly directed fingernail-shaped louvers admitting air into the slit formed beneath.

Bottom plate 48 of circular shape and made from heavier gauge steel includes a central opening 50 and a downwardly directed circumferential flange 52 to which are welded four legs 54 made of metal rods and angled outwardly for stability. Shroud 40 fits tightly around the flange 52 but is detachable for stacking separately in egg-carton style. The support assemblies consisting of the bottom plate 48 and the legs may also be separately stacked for ease of shipment and storage in offseason periods.

One of the legs includes a horizontal rod bracket 56 serving to support an aboveground oil distribution line 58. Nozzle 30 connected to the oil line by means of an elbow 59 and adapter 60 is held centered within air inlet opening 50 by means of a Y-shaped bracket 58 welded to the bottom plate 48 and straddling the opening 50 as shown. Air inlet opening 50 and the uniformly distributed air inlet orifices 42, 44 and 46 in the cone-shaped shroud Serve the same purpose as in the embodiment previously described. This embodiment includes no upper baffle, but its taper serves the same function, mainly to constrain the flames within the shroud sufficiently to permit complete burning of the oil-.air mixture introduced by the nozzle 30 as now to be described.

F[he nozzle illustrated in FIGURE 3 is connected to the oil supply line by means of an adapter 60 threadably attachable to the pipe at its lower end and to the nozzle at its upper end. The nozzle itself includes a jacket 67 having external threads 62 to secure it to the adapter 60 and internal threads 64 within a substantially cylindrical cavity 66 formed axially therein. The cavity 66 receives a cylindrical insert member 68, a threaded support member 70 holding the insert member within the cavity, and a filter 72. The latter includes a filtering portion 74 secured to a threaded hollow flanged portion 76 received in internal threads 64 of nozzle jacket 67. Oil is driven under pressure from the oil line through filter portion 74 into internal cavity 78 of the filter member. It is further driven through an axial hole 80 in threaded Support member 70 and into the cylindrical cavity 82 of insert member 68. From this region it exits through a pair of holes 84 in the sides of the insert member and into the annular cavity 86 around it within nozzle jacket 67.

The nozzle cavity 86 terminates in a cone-shaped roof 88 and oil exit orifice 90 at the apex thereof. Orifice 90 itself is very minute, of a size adapted, in combination with other features to be described, to break up the oil into a fine mist. The top of insert member 68 includes an upper cone-shaped section 92 (FIGURE 4) converging upwardly at an angle identical to that of the coneshaped roof 88 of the nozzle cavity, and a lower coneshaped section 94 having a sharper angle of convergence and intersecting the upper cone-shaped section 92 along a circular intersection line 93.

The upper cone-shaped portion 92 of the insert member terminates in a flat apex surface 96. Four oil delivery channels 98 extend across this section from lower coneshaped section 94 to apex surface 96. The channels have respective cross-sectional areas comparable to the smallest portion of orifice 90 and impart extremely high velocity to the oil forced through them under pressure. They converge upwardly and inwardly toward the orifice 90 when viewed in a lateral direction, but are offset from the central axis of the nozzle to intersect the circular apex surface 96 tangentially at points spaced around its circumference. With this arrangement the oil is driven from annular cavity 86 surrounding insert member 68, across lower cone-shaped section 94 into oil delivery channels 98 and finally into and out of the orifice itself, whereupon bei cause of the offset of channels 98 a swirling, upwardly spiraling turbulent motion is imparted to the oil particles. They consequently exit from orifice with extremely high angular velocity tangential to the lip of the orifice, .and being flung from the orifice tangentially are broken up into very fine particles or oil droplets which form a lighter-than-air oil mist. Prior to ignition the mist fills the entire volume of the shroud 10 (or 40), and when ignited fills the entire volume with flames.

lThe described oil-mist generating nozzle combined with one of the burner shrouds described, constructed to provide convection currents causing immediate mixture of the oil mist with the air, constitutes a great improvement over prior orchard heating burners and similar units in terms of burning efficiency. Because of the problems of air pollution, more efficient orchard heating burners are very much in demand, and it is found that this particular nozzle-shroud combination satisfies the requirements of smog-control laws and is much more economical to operate, as well.

`Other advantages will be recognized by those skilled in the art.

We claim as our invention:

1. A convection-radiation heating system comprising oil supply means including an oil line .and means for driving oil through said line under pressure; .an oil mist generating nozzle connected to said line; and a flame-constraining shroud coupled with said nozzle; said shroud including side walls having air inlet openings therein, a bottom plate adjoining said side walls and having a central air inlet opening therein, means for positioning said nozzle cen trally within said opening, means for supporting said bottom plate above the ground for entry of air into said opening, and means constraining exit of burning oil-air mixture from said shroud to maintain substantially complete combustion of said oil mist; said nozzle including an outer jacket having means therein defining an inner cavity coupled to receive oil from said line, an upwardly directed oil exit orifice in said nozzle jacket, and oil delivery paths extending between said inner cavity and said orifice, said paths being directed with respect to said orifice to impart sufficient angular velocity to said oil as it exists from said orifice under pressure to separate said oil into a mist of droplets lighter than air to be mixed in said shroud with air entering through inlet openings.

2. An oil burning convection-radiation heating device for heating large volumes of air comprising:

(a) a ame constraining shroud having side walls and a bottom plate adjoining said side walls to define a burner cavity, said shroud having air inlet openings in said side walls, a flame exit opening at the top thereof, a central air inlet opening in said bottom plate and means supporting said bottom plate above the ground for entry of air into said central opening; yand (b) an oil mist generating nozzle adapted to be positioned in the air inlet opening in said bottom plate, said nozzle including (i) means for coupling said nozzle to a supply of fuel oil under pressure,

(ii) an outer jacket having an oil exit orifice at the top thereof and adapted to direct oil upwardly into said shroud,

(iii) and oil delivery channels within said jacket providing oil flow paths from said coupling means to said orifice, said paths converging upwardly and being offset laterally of said jacket to impart to oil forced through said channels and orifice under pressure a sufficient angular velocity tangential to the orifice to separate the oil into -a mist of lighter-than-air droplets Within said shroud.

3. The heating device defined in claim 2 wherein said bottom plate includes a bracket secured across said central opening for positioning said nozzle therein, and wherein said means for supporting said bottom plate above the ground comprises a plurality of legs coupled to said heating device at locations spaced around the periphery of said bottom plate and adapted to be imbedded in the ground.

4. The heating device defined in claim 3 wherein said legs are secured to said side walls and have outwardly extending upper ends against which downward force may be applied to imbed said legs in the ground, said legs being spaced to accommodate therebetween the shroud of another such heating device when stacked thereon.

5. The heating device defined in claim 4 wherein said side walls comprise a cylindrical surface having vertically spaced circumferential -rows of air inlet openings therein, and a flame-constraining circular top bafile connected circumferentially to said cylindrical side wall surface and having a central arne outlet opening therein.

6. The heating device defined in claim 3 wherein said bottom plate is detachable from said side walls and said legs are secured to said bottom plate and diverge downwardly to accommodate therebetween another such heating device bottom plate when stacked thereon.

7. The heating device defined in claim 5 wherein said side walls comprise a frusto-conical surface having upward flame-constraining convergence operable to maintain substantially complete combustion of oil mist within said shroud and enabling stacking of a plurality of said shrouds one on .another separate from the bottom plates thereof.

References Cited UNITED STATES PATENTS 1,326,488 l2/19l9 Fisher. v 2,055,864 9/1936 Harsch. 2,269,831 1/1942 Senner et al 126-59.5 X 2,664,312 12/1953 Czarnecki et al. 158-78 X 3,205,885 9/1965 Baxley 126-595 OTHER REFERENCES Meyer et al.: German App. No. 1,045,151, pub. Nov. 27, 1958.

CHARLES l. MYHRE, Primary Examiner.

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