US2284157A - Orchard heater - Google Patents

Description

May 26, 1942. A. s. LEONARD 0110mm: HEATER Filed Nov. 12," 1957 5 Sheets-Sheet l May 26, 1942. A. s. LEONARD 2,284,157

ORCHARD HEATER Filed Nov. 12, 1957 3 Sheets-Sheet 2 //v VWTOR lrf/wr dfep/ien L eonaro .dflbr/iey Mgy 26, 1942. s, LEONARD I 2,284,157

ORCHARD HEATER Filed Nov. 12, 1937 i 3 Sheets-Sheet 3 W n/70R Ari/Mr -SYepMzr; Leo/7am Afforneg Patented May 26,- 1942 NITED STATES PATENT orrice HEATER I Arthur Stephen Leonard, Davis, CaliL, assignor to California Fruit Growers Exchange, Los Angeles, Calif., a corporation of California Application November 12, 1937, Serial N 174,170

Claims. (01. 158-91) In the operation of orchard heaters many seriousproblems are met with. At least two of these arise from the formation of smoke or other more or less solidsubstances during the combustion of the fuel; These are the formation of clouds of smoke in the atmosphere and the filling up of the heater or parts thereof with soot and coky and resinous residues. Many attempts have been made to reduce the amount of smoke discharged into the atmosphere by orchard heaters for the sake of convenience of neighboring residents. Moreover, it seems desirable to burn the fuel as completely as possible so as to obtain more heat from a given amount. It is imperative to reduce the amount of soot and other residues deposited heaters by diluting fuel vapors and/or gases with products of combustion before admixing any substantial quantity of air.

A further object of my invention is the provision of a new and improved type of burner for orchard heaters.

Other objects and advantages including more specific objects and advantages embraced within the. scope of those broadly stated above will appear more fully and at large hereinafter and others will be obvious to those skilled in the in the interior of the heater. Otherwise, during the cold season the capacity of heaters of the bowl type may be materially reduced. Obviously during the winter such heaters must always be refilled promptly after burning so as to be ready for any further cold spells. It is manifestly impossible, then, to clean out the heaters, and so the soot or carbon or other residues accumulate fromoneburning to the next. This accumulation may become very substantial and may not only seriously impair the capacity of the heater to hold the customary charge of oil, but also may interfere with the proper operation of the heater.

art, appearing in part at least from contempla tion and use of the inventions described and claimed. v p

I obtain these and other objects and advantages by means of apparatus embodying the broad principles of my invention, these apparatus being illustrated in the accompanying drawings in which:

Figure 1 is a vertical section of one form of my improved heater.

Figure 2 is a vertical sect'on of a known type of heater modified to employ my new method of operation.

Figure 3 is a vertical, sectional view taken at the line 33 of Figure 4 and showing the modi- .fication of another known type of orchard heater 4 to adapt it to my new method of operation.

I have now discovered that the deposition of soot and other residues within the heater and the discharge of soot and smoke into the air may be very materially reduced if not eliminated altogether. I accomplish this and other important results by the apparatus more fully described hereinafter. Accordingly an object of my invention is to provide and disclose means for operating orchard heaters inwhich the deposition and discharge of soot and the like is very greatly reduced or substantially eliminated.

Another object of my invention is to provide and disclose means for burning carbonaceous materials in orchard heaters so as to reduce the size of carbon particles formed during combustion.

A still further object of my invention is to provide and disclose means for burning carboncontaining fuels in orchard heaters by re-circu-' lating at least a portion of the products of combustion and diluting the fuel gases and/or vapors therewith prior to the combustion of said fuel.

More specifically, an object of my invention is Figure 4 is a horizontal. section and plan view taken along the line 4-4 of Figure 3.

Figure 5 is a detail view showing the construction of my preferred form of air jet.

to provide and disclose orchard heaters in which products of combustion are mixed with fuel gases and/or vapors prior to combustion of the same.

A more limited object of my invention is to provide and disclose means for operating orchard Figure 6 is a vertical section of another form of my improved heater and likewise illustrates stood that in the combustion of the materials in 7 this form the chemical compounds are broken down to liberate free carbon and other elements. Incandescent carbon particles create a luminous flame. When .the particles of the carbon cool below incandescence before they are completely burned, smoke and soot'result.

In dealing with the.problems of smoke and 5001; in connection with orchard heating some rality of air-admitting apertures 21.

very definite limitations are met with and must be taken into account in any successful handling of these problems.

For example, it is well known that under conditions requiring orchard heating the layers of air nearest the ground are colder than those next above. The need then is to heat the layers near the ground andto avoid loss of the heat into the upper .air.

relatively lower heat output per unit, rather than a smaller number with relatively large heat output per unit. This avoids the tendency of a large This makes desirable the use of a larger number of heating units with unit to create astrongupdraft and thus to carry away the heat into the upper air. Likewise the smaller heating unit will be less likely to overheat the foliage and other parts of the plants 7 near the heater.

These considerations as well as others make it imperative that individual heating units be relatively inexpensive, which means that one cannot resort to elaborate constructions to be sure that the'fuel is all subjected to conditions of tempera-'- ture, air-mixing, and draft that will result in burning of the fuel without formation ofsoot, smoke, residues, etc. Moreover, if new developments are to come into use promptly, they should preferably be of such a nature that, to a very large extent at least, present equipment can be utilized. 'One of the important advantages of my new development resides in the fact that it can be adapted to present equipment, thus protecting the investment in present orchard heating equipment which in the citrus industry alone amounts to a tremendous amount of money.

With the above and other considerations in mind I may apply my present invention-to the problems of orchard heating by means of specific equipment such as that hereinafter described in detail and illustrated in the accompanying draw- Figure'l and Figure 2 show modifications of the construction of a known type of heater, known commonly as the jumbo cone heater. This is formed of a bowl 2|, not completely shown, a cover schematically indicated at 22, with a throat or opening 23, a combustion chamber indicated generally at 24, and a plurality' of openings or 'louvres indicated at 25. Within the combustion 'invap'or or gaseous formthe tendency toward the formation of soot, smoke, etc.', may be reduced 'or' altogether eliminated by modifying the combustion by adding to the combustion mixture some gaseous material that willnot itself take part in the combustion to any substantial degree. Combustion'products derived from the burning of carbonaceous materials will be of such a nature that, when add d to a mixture'for subsequent combustion, they*will not take part to any substantial degreein-the later combustion. A satisfactory means for accomplishing this result is the recirculation of at least a portion of the products of a continuing combustion. and adding these to the combustion mixture before it is burned.

I apply this principle in a'practical way to the operation of orchard heaters by providing.

means for the recirculation of at least a portion 'of the combustion products. In the constructions herein described and shown in the accompanying drawings several embodiments of such means are illustrated.

As shown in Figure 1 the recirculating means is comprised of a return pipe 30. This may preferably be introduced through the side of the stack 29 as at 3| and may be provided with an intake portion 32 which, as illustrated, may be of frusto-conical Jrm. This gives a general correspondence between the shape of the intake portion 32 and the stack 29 so as to provide throughout that portion of the stack an opening of at least roughly uniform cross section for the outgoing gases. The pipe is preferably introduced through the cover 22 as at 33. It may preferably be provided with a suitable damper 34 which may i I in detail in Figure 5..

In the operation of this heater the bowl may i be filled with a suitable fuel such as the marine Diesel, bunker grade, fuel oil commonly used for orchard heating. The filling may be done through the usual filler opening in the cover. The heater may be lighted in the usual way. I may preferably provide that the heater is tightly covered so that no air is admitted except through a jet or jets 36. When the heater is burning a flame may be maintained at the jet' or jets 38.

This flame will consume to a, substantial extent the combustible portion of the air admitted through the jet. Due to the vertical positioning controlled and ,operated the burning of this flame within the bowl of the heater does not result in troublesome deposition of carbon,'etc., within the bowl of the heater or upon the cover thereof.

The flame about the jet or air vent 36 serves to heat the surface of the oil and assist in vaporizing the same so as to keep the heater as a whole in operation at the higher burning rates. The jet flame is not essential. At present I prefer not to use it at low burning rates.

The fuel vapors pass through the throat 23 and into the combustion chamber 24 where they will burn in the usual way in admixture with and in the presence of added air entering through the openings 21 and louvres 25., By means of a suitable recirculating device such as the return pipes 30 shown in Figure l a portion of the combustion. products is recirculated into the bowl and admixed with the fuel vapors prior to the combustion thereof.

It is found that the recirculation of a portion of the combustion products and admixing thereof with the fuel vapors results in a very substantialreduction in the amount of soot and smoke formed, which, under the best conditions, may.

relatively smaller carbon particles or-aggregates as the fuel vapor undergoes decomposition into its elements in the combustion zone. These smaller carbon particles, as each is burned in the I presence of admixed air, will be much more readily consumed and thus be completely burned, or at least more nearly completely burned, before passing from that portion of the combustion zone within the heater in which the burning fuel particles are maintained in a state of incandescence. The practical result is that smoking of the heater to the outside air and deposition of carbon, soot, etc., within the heater are substantially completely eliminated. This achieves the three-fold advantage of avoiding the smudge in the air which is so disagreeable to everybody concerned, of maintaining the full capacity of the heater at all times, and of obtaining the maximum, amount of heat from a given amount of fuel by burning the fuel completely.

The upward draft of the combustion products within the stack will cause a desired portion thereof to go into the intake portion 32 and back through the pipe is and into the bowl at 83. When it is desired to regulate the rate of return flow, this may be done by means of a damper it.

I The embodiments shown in Figure 1 and in Figures 3 and 4 have the. advantage that they can readily be provided with a cap .or cover over the stack to exclude rain.

The air jet 36 illustrated in detail in Figure 5 consists of a frusto-conical portion 4% provided near its smaller inner end with a cylindrical collar ample, four) of perforations 48. It is found that a jet of this type will retain the flame at the jet in the embodiment illustrated in Figures 6, v,-

and 8 the heater is provided with a stack 65, pref erably of inverted frusto-conical shape as shown.

. Within the upper end of this stack is positioned The return flow may be accomplished by means new heaters or of converting to the employmentof my invention known types of heaters at present in use. V

In the embodiment shown in Figure 2 the type of stack which is at present standard for this type of heater has been retained. This heater is modifled by the introduction of a return flow construction which, as illustrated, consists of entrance pipe or portion 37 which, at 38, is connected to return pipe 39 which enters the cover an entrance portion at which at it is joined to the return flow pipes 52. These pass through the cover as at 53. If desired the pipes 52 may be supplied with suitable dampers. The operation of this heater is substantially the same as that previously described.

In Figure 6 there is also illustrated a new and improved type of burner indicated generally at 56. This burner is comprised of a cylindrical portion 55 and a frusto-conical portion 55 and, in one preferred embodiment, is approximately 6 inches high, being approximately 6 inches in diameter at the lower end and 8 inches at the upper end. It is provided with 5 rows of .holes, the holes in each row being approximately equally spaced around the burner. In the preferred embodiment mentioned the top row consists of 5 holes inch in diameter, the second row of 10 holes /2 inch indiameter, the third row of 20 holes inch in diameter, the fourth row of 40 holes inch in diameter, and the bottom row of holes drilled with a No. 20 drill (0.161 inch in diameter).

as at it. The method of operation of the various embodiments is substantially the same and will not be repeated in detail.

Figures 3 and 4 illustrate the adaptation of a known type of heater known commonly as the Lemora heater to the employment of my invention. This known type of heater, due to its construction, gives to the combustion products as they rise through the stack M, a strong swirling action which, in the common form of this heater and in the embodiment shown in the drawings, is'

counterclockwise in direction when viewed from the top of the heater. I introduce through the sides of the stack one or more entrance pipes 2, two such pipes being illustrated in Figures 3 and e, as more clearly appears from Figure 4.

These entrance portions 62 lead. back through pipes at through the cover and into the interior of the bowl.

The swirling action of the combustion mixture arises from the particular arrangement of a plurality of openingsor louvres it about the flame spreader it, all in a manner well understood in Within this burner and centrally thereof there is suitably supported a flame spreader 51 which may be said to be formed of two hollow cones joined together at their bases, with one apex extending downwardly into the burner and the other up into the stack. In an embodiment corresponding in dimensions to the dimensions given for the exterior portion of the burner, the flame spreader would be approximately 4 inches in diameter and 10 inches from apex to apex.

The objective sought in my burner is to pro-v vide a comparatively narrow space through which the combustion mixture must pass, first introducing the air through a large number of very small openings and then progressively through a smaller number of larger openings.

,This results in the thorough admixture of the may be adapted to other applications with desirable results. I' am also aware that numerous changes and modifications may be made in the details of procedures described and in the details of the apparatus described and shown. I

therefore do not propose to limit myself to the- 4 I exact details-of construction and procedure described, but only as necessitated by the prior art and as indicated in the appended claims.

Having thus described my invention in such full, clear, concise and exact language as to enable others skilled in the'art to make and use the same, I claim as my invention and desire to secure by Letters Patent the following. I

I claim:

1. In a unitary, portable orchard heater, a fuel receptacle having bottom and side walls and adapted to hold as a body a charge of oil to beburned, said receptacle being provided with a cover having vents therein, a combustion chamber centrally positioned over said cover and contioned above said combustion chamber, one or more auxiliary stacks having an entrance portion disposed within the main stack and above the combustion z'one, and communicating with the receptacle for the body of oil at a point ahead of the combustion chamber, said auxiliary stack being positioned outside of the main stack and nected therewith, a main stack centrally posi- 7 adapted to provide for the return of a portion of the products of combustion from the main stack to the fuel receptacle and over the bodyof oil, whereby there is obtained a mixture of the returned products of combustion with the vapors from said body of oil prior to the entry of said vapors into the combustion chamber.

2. In a unitary, portable orchard heater, a

fuel receptacle having bottom and side walls andadapted to hold as a body a charge of oil to be burned, said receptacle being provided with a cover having air vents therein, a combustion chamber centrally positioned over said cover and connected therewith by means of a throat, a main stack centrally positioned above said combustion chamber, one or more auxiliary, stacks having an entrance portion disposed within the main stack and above the combustion zone and communicating with the receptacle for the body of oil at a point aheadof the combustion chamber, said auxiliary stack being positioned out-l side of the main stack and adapted to provide for the return of a portion of the products of combustion from the main stack to the fuel receptacle and over the body of oil, whereby there is .obtained a mixture of the returned products of combustion with the vapors from said body of oil prior to the entry of said vapors into the combustion chamber.

3. In a unitary, portable orchard heater, a

fuel receptacle having bottom and sidewalls and adapted to hold as a body a charge of oil to be burned, said receptacle being providedwith a cover having air vents therein, a combustion chamber having a plurality of openings or louvers centrally positioned over said cover and connected therewith by means of a throat, a baffie plate within said combustion chamber, a main stack centrally positioned above said combus-. tion chamber, one or more auxiliary stacks having an entrance portion disposed within the main stack and above the combustion zone and communicating with the receptacle for the body of oil at a pointahead of the combustion chamber, said auxiliary stack being positioned outside of the main. stack and adapted to provide for the return of a portion of the products of combustion from the mainstack to the fuel receptacle and over the body of oil; whereby there is obtained a mixture of the returned products of combustion with the vapors from said body of 5. In a unitary, portable orchard heater, a fuel receptacle adapted to hold as a body a chargeof oil to be burned, said receptacle provided with a I cover, a combustion chamber positioned over said cover and connected therewith, a main stack positioned above said combustion chamber, one

or more auxiliary stacks having an entrance portion disposed within the main stack and communicating with the receptacle for the body of oil at a point ahead of the combustion chamber,

and adapted to provide for, the return of a portion of the products of combustion from the main stack to the fuel receptacle and over the body of oil, whereby there is obtained a mixture of the returned products of combustion with the vapors from saidbody of oil prior to the entry of said .vapors into the combustion chamber.

- ARTHUR STEPHEN LEONARD.

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