US2286366A - Orchard heater - Google Patents

Description

imma@ i6, 1942.

W. A. LEA ETAL.

ORCHARD HEATER Filed Nov. 26, 1937 2 Sheets-Sheet l For Maf/)w1 June 16, 1942. w. A. LEA ETAL 2,285,366

ORCHARD HEATER Filed Nov. 26, 1937 2 Sheets-Sheet 2 l Patented June 16, 1942 's UNITED STATES PATENT ori-ICE oRCHARD HEATER Walter A. Lea, Los Angeles, and Earl Vincent Ehrhardt, Altadena, Calif.

Application November 26, 1937, Serial No. 176,614

3 Claims.

This invention relates to air heaters andparticularly to heaters adapted for use in batteries of units for heating extended areas at a plurality of points of heat generation. In the description and drawings, orchard heating has been selected as an illustration of a type of installation of heaters of our invention, but We do not wish our invention to be considered as limited to this adaptation, since it is also capable of employment to heat shop rooms, buildings, and'other extensive volumes of air.

It is one of our objects to provide a heater which shall completely and efficiently burn a gaseous fuel supplied to it without the production of smoke, soot, or other products of incomplete combustion.

It is another object to provide a heater which shall be automatically ignited by the flow of fuel to the heater, or by the pressure of the fuel in the supply conductor.

It is another object to provide a heater which shall be adapted to receive a fuel of the type which is liquid within the range of atmospheric temperatures above freezing at pressures above atmospheric normal, but which is gaseous at temperatures above freezing at normal atmospheric pressurel and shall be further adapted by lowering its pressure to convert a liquid fuel of this type into a gas and then burn it.

It is another object of our invention to provide a heater which shall be constructed to mix and heat air with the heated products of combustion and thereby increase the quantity and velocity and lower the temperature of the resulting mixture of gases discharged from the heater.

It is still another object of our invention to provide a heater having both a pilot burner and main burner and consuming fuel supplied under pressure in which either the pilot or the main burner shall operate according to the degree of pressure in the supply conductor.

It is still another object of our invention to provide a heater which shall discharge its heated products in a desired horizontal direction and more particularly in a focused horizontal stream, to more gradually and uniformly warm the ground air, than is4 otherwise possible, to the end that the layer of warm air at higher levels which is above the safety temperature may not be penetrated by localized currents of vertically moving columns of hot air. This feature, by which we are able to propel the heated products in any desired horizontal direction, makes it possible to Y oppose, halt. and turn back horizontally moving currents of cold air that may be moving toward or .into the orchard or other area which it is desired to warm.

It is a further object of our invention to provide a heater which shall be so constructed as to secure its heating effect principally from convection, and which shall havea minimum of'radiation to the end that the ground and surrounding objects may not be unduly heated with destructive effect. l

Our invention, also, has as -one of its objects the provision of a heater which shall be adjustable in rate of output of thermal units from a relatively very small quantity to a quantity of heat units much above prior practice in orchard heating, to the end that fewer heater units may be required in a given area, and at the same time no disadvantages flow from the corresponding greater concentration of heat emitted from each u nit, such as scorching the ground or foliage or piercing the ceiling f warm upper air stratum.

It is a further object of our invention to make provision for the use of our heaters in batteries which shall be subject to a unitary remote control of the ignition, for the selection of either pilot or main burner, and of the rate of production of thermal units of the individual heaters.

It is a further object of our invention to provide a heater which either singly or in batteries may be supplied with a fuel in liquid form in conductors of small size and cost, which fuel shall be converted to gaseous form at the heater units. To accomplish this advantageous result, we prefer to employ as fuels butane, propane, pentane, hexane, or other hydrocarbon of this type, which are liquid at all ordinary atmospheric temperatures above `freezing in combination with superatmospheric pressures ranging upward from about ten pounds per square inch, depending upon the temperature and the particular type of fuel,' but which fuels at the same temperatures are gaseous at normal atmospheric pressure. Wel accordingly-Store the fuel in tanks under pressure, and pipe it under pressure and in liquid l:

form to the heater units, where the pressure is released and the fuel is gasiiled and burned.

It is a further object of our invention to provide means for maintaining the pressure in the supply system suiliciently high to ensure the fuel being in liquid form until it reaches the heater units, and also to ensure a constant rate-of supply to the heaters, with a resultant constant rate of liberation of thermal units.

Still other objects and advantages of our inthe burner end of the heater taken along the line 5-5 of Fig. 4, the pilot assembly being shown in side elevation in front of the section plane.

Fig. 6 is a vertical sectional view of the pilot assembly taken along the line 5-6 of Fig. 5.

A horizontally disposed cylindrical heater flue II receives the jet of burning gas at its one end I3, and conducts and directs it longitudinally within its interior chamber I2, the heated products of combustion being discharged horizontally from the other and open end I4 of the ilue II. As the Jet of flame travels through the flue, air is drawn in through louvered apertures I5.. These apertures I5 are designed to supply an excess of air, this excess is mixed with and heated by the hot gases of combustion, and both increases the volume and velocity and correspondingly lowers the temperature of the resulting gaseous discharge from. the ue. The cold air entering through the apertures I5 also lowers the temperature of the ilue walls and reducesradiation therefrom. f;

The imector action which tends to draw air into the stack is greatest 'at the burner end I3 of the stack and least at the discharge end I4. `Accordingly the apertures .I5 maybe of variable size,increasing progressively from the burner end I3 to the'discharge end I4, being so formed that the planes of the louvered apertures are progressively changed in angular relationship to the plane tangential to the adjacent Aportion of the flue wall, the planes of the bounding edges of thev apertures at the burner end lying fiat in the flue wall, and the planes of the bounding edges of the apertures at the discharge end being tilted at a substantial angle to the longitudinal lines of 'the ue wall. This design of the louvered apertures provides for an intake of air into the flue in substantially equal amounts through the several apertures, irrespective of their position longitudinally of the flue, since the apertures of greater diameter and greater angular set at the is movable upon the ground l1. The vertical cylindrical end wall 22 of the flue II is formed with intake openings 23 to admit air to the interior chamber I2 of the flue. end wall to make these openings 23, the metal is cut on three sides of the opening and the flap thus formed is bent inwardly to provide a deij'lector 24 to impart a spiral movement to the air rushing in through the openings, which movement gives the air and burner flame a thorough mix resulting in more complete incorporation of the excess air in the heater discharge.

The burner casting I3 comprises a horizontally disposed hollowmixing cylinder 25 and a discharge end offer less resistance to the ilow of air therethrough, a feature which compensates for the lesser degree of injector action at the discharge end. The angular set of the aperturesv also prevents discharge of the gaseous contents of the flue through the louvered apertures, which would dissipate the heat laterally of the flue, lnstead of discharging it in a horizontal jet as it is contemplated by our invention. l

-The flue II is rigidly mounted at itsdischarge end upon a supporting standard I5 which is movable with respect to the ground I1 upon which it rests. At the burner end, the flue I I is provided with an end wall 22 which may be integral with the side walls of the ue II or secured thereto by welding, by bolts, or in any well known Inanner. The end wall 22 is secured by screws I3 to a burner casting I9, which is in turn. supported upon a standard 23. This standard 23 is provided at its lower end with a pedestal 2l which goose neck projection .25 extending rearwardly from the under side of the cylinder 25. The fuel gas and injected air enter the cylinder 25 through a rearwardly extending cylindrical intake hood 21 secured in an opening 28 in the rear wall 23 of the cylinder 25 and in axial alignment with the cylinder. The air and gas are thoroughly mixed in the cylinder 25, combustion takes place therein, and they leave it through a circular opening 33 at its forward end, entering the flue as an extended llame therein.

The standard 23 consists of a lower solid vertical rod 3|, a T fitting 32, threadedly mounted at the upper end of rod 3|, and an upper pipe stion 33 having threaded engagement with the T 32 at its lower end and at its upper end with a boss 34 formed on the under side of the projection 25. This boss 34 has a central vertical bore 35 communicating with the interior of the pipe section 33 at the point of threaded engagement. The bore 35 also communicates at its upper end with a bore 35 in the gooseneck projection 25, which bore extends horizontally from the front end of the projection 25, rearwardly to a vertical leg 31 thereof, thence upwardly to a horizontally disposed end portion 33, and thence horizontally to the end of projection 23. The bore 35 at the end portion 38 is threaded and into it is screwed the burner tipor nozzle 33 in axial alignment with the intake hood 21.

The forward,v end of the bore 33 has an enlarged portion 43 which is threaded at its front end to receive the rear end of the cylindrical preheater 4I, which projects horizontally into the flue chamber I2 between the axis and lower wall thereof fora relatively short distance, and is closed at its outer end with a cap 42. A horizontal pipe section 43, open at both ends, is'

threadedly mounted at its rear end in thefront end of that portion of the bore 35 which is oiv This pipe section projects into 'ends respectively. The head 43 is provided with a central vertical bore 43, oi' which the lower end is threaded to receive the vertical leg of a T- shaped fitting 53. The horizontal portion of fitting 53 is provided with an axial bore 5I, of

which one end is enlarged and threaded to receive a compression joint 33 at the end of a fuel supply pipe 52 which conducts fuel from the source of supply to the heater. The other end of the bore 5I is formed with a valve seat 53 and has mounted therein an adjustable needle valve 54 of standard construction. Bore 5I communicates with bore 43 through a vertical bore 5Ia in the vertical leg of the tting 53. When butanel 6r similar liquid fuel is employed, it is conducted as a liquid under pressure to the heater and as it In stamping the passesthrough the needle valve in fitting 68 its 1 the T 32, and a' horizontal short nipple 56, which has a threaded connection at one end with the jtting 55, and a threaded connection at the other end with a band 46 which encircles and is rigidly secured to the cylinder 44 about midway of the ends of the cylinder. 'I'he interior 61 of the nipple 56 communicates at one end with the lower portion 58a of the interior chamber 58 of the cylinder 44, and at the other end with the interior of the elbow 55, which in turn communicates with the interior chamber of the T 32 and the pipe 33.

Within the cylinder 44 is slidably mounted a piston 59 which is adapted to impart a reciprocatory motion to a piston rod 60. This rod is suitably secured by a wrist pin connection 60a to the upper face of the piston and is slidably mounted withinv an axial bore 6| extending vertically through the cylinder head. 41. As the piston 59 is moved upwardly by the pressure of the fuel entering the cylinder 44 from the pipe 52, it uncovers a main fuel outlet port 62 asits lower end passes above the level of the bore 51.

At the same time a small fractional part oi the fuel leaks by the piston between it and the walls of the piston 44 into the upper chamber 68h. This leakage then passes through a duet 63 in the cylinder head 41, and through a bore 65 of a fitting 66 and issues from the cylinder into a pilot tubing v64, which is secured to the cylinder head 41 by means of this fitting 66. While not usually necessary, the piston wall may be provided with a. longitudinal groove 59a to ensure passage of this small quantity of fuel by the piston to chamber 58h. When the piston reaches the upper limit of its movement, a valve disk 81, made of synthetic rubber or other suitable material and fastened to the upper face of the piston, contacts an annular valve seat 68 formed on an annular projection 68 extending downwardly from the cylinder head 41, andhalts the passage of fuel from the cylinder chamber 58 to the pilot tubing 64.

The,pilot tubing 84 terminates at a point such that -when the fuel issuing from it is ignited, the pilot flame will be projected into the neighborhood of the fuel jet issuing from the nozzle 39 of their contact relationship is of such a character that when the disk is given a rapid movement of rotation through a small arc, sparks are generated sunicient to ignite the'jet of fuel gas issuing from the adjacent pilot cup 18. This rapid rotational movement is imparted to the disk by'means of a mechanism described as follows.

An impulsewheel 88 is loosely mounted upon the pin 14 between the channel flanges 18 and 15. It is formed with an axial projection 8| extending toward the channel flange 15', having jaws 82 which engage in mating relationship jaws 83 formed on a disk 84 which is keyed or otherwise ixedly secured to the pin 14. The

impulse wheel 88 is resiliently held axially against the`disk 84 by means of a spiral spring 85 interposed between the ange 15 and the impulse wheel. The impulse wheel is provided with an integral dog 86 which is resiliently held in a vertically depending position against the upper end of an arm 81 by means of a spring 88 secured at itsl upper end to the dog 88 and at its lower end to the flange 15;y The arm 81 is channel-shaped in cross section and is arranged withits flanges 88 extending toward the upright 12. A block 9| is rigidly secured between the fianges 89 and the arm 81 and is formed with an upwardly extending lip 92 which mates with a notch 83 formed on the its upper end tol a cross arm 98 which is integrally formed upon and projects from the arm 81 near its lower end, and which extends through, and is free to move vertically in, a slot 91 formed in the standard web 16.

A cylindrical hood 88 formed with a `ring of p .louver openings 99 and supported loosely upon the elbow 55 serves to enclose all parts of the pilot assembly 45, protecting it from rain when the heater is used in exposed locations, and shielding the pilot flame from wind. An upper horizontal portion ||l\'| of the hood 98' serves the main burner. The upper end of the pilot tubing 64 is provided with a mixing cup 18 formed with a central tapped opening 1| in its bottom wall into which the upper end of the tubing is threaded, and having two air intake openings 1|a also in its bottom wall which admit air for comv bustion of the pilot flame.

The frame for the igniter mechanism is a channel-shaped upright 12, which is mounted in position by means of a nut 13 threaded upon the nipple 56, by which it is drawn into fixed position against the band 46. A pin 14 is revolvably mounted between iianges 15 and 15' of the up to direct the pilot name toward the fuel jet of the main burner and insures a quick positive ignition thereof.

The igniter mechanism is so constructed and arranged that .when the pistion 59 is at its lowernlost position, the block 9| and the dog 86 are slightly separated, and the upper end of the web 84 rests upon the back of the dog. As the vpiston moves upwardly, the block 9| engages the i dog 86 and rotates the wheel 80 until, as shown in dotted lines in Fig. 6, the dog 86 disengages the lip 92 and the impulse wheel 80 is given a sudden rotational movement by the action of the spring .88. The jaws 82 which latch idly Aby jaws 83 during the upward movementof the and designated with the numerals |0| and |02. The

vantage in that when one tank is emptied in the operation of the heating system, it can be shut off from the heaters and refilled while the other tank is furnishing the fuel supply. The fuel outlet pipe |03 is equipped with shut-off valves |04 and |05 by which the supply network of pipes shown in Fig. 3 can be connected to either or both of the supply tanks. We prefer to divide this supply system of pipes into two or more sub-systems, |01 and |08, each subsystem being provided with a shut-off operating valve so that either can be operated without the other, or both can be operated simultaneously, as may be desired.

It will be understood that the heaters may be grouped in one or more systems for group operation as indicated by the size and other conditions of the orchard We have illustrated in Fig. 3 a sample installation. In this installation the sub-system of pipes |01 is connected to heaters disposed about the four edges of a rectangular orchard. The heater units, as will be understood by reference to the above description of an individual heater unit, are capable of being placed with their ilues pointing in any desired direction. Heaters |08 are shown in Fig. 3 as directed outwardly toward the boundaries of the orchard, and, in an installation such as shown in Fig. 3, can be fired in advance of the firing of the remaining heaters H0 supplied by pipe system |08, which heaters are located in the central portions of the or# chard. Heaters ||0 are shown with their nues pointing toward the prevailing movement of cold air asindicated by the arrows A.

The liquid fuel, indicated in Fig. 2 by the numeral ||2, is held under pressure in the tanks. As the tank is gradually emptied of its supply the pressure therein tends to drop. Since the pressure of fuel at the heaters determines the rate of flow of fuel thereto, and consequently the rate of liberation of thermal units, it is desirable to maintain a fairly constant pressure in the supply tanks. VWe accomplish this by providing a tank heater H3, which heater may be similar to those used in the orchard. Such a heater may be fed from`the fuel outlet pipe |03 through a pipe II4, and the feed controlled by a. needle valve such as shown at 54. in Fig. 6. Water in a closed system, which is provided with an expansion tank '||9, is warmed in a coil ||5 and conducted through a pipe ||6 to a heating loop ||1 mounted within the fuel tank and adjacent its bottom, and thence back to the heater ||3. By regulation of the flow of fuel to heater ||3, and by regulation of the flow of water by means of a valve H8, the liquid fuel within either tank can be raised to any desired temperature, and the pressure thereby increased to any desired degree, maintaining a. constant pressure at the heaters or varying it as desired, according to the varying heating needs of the orchard. It will also be apparent .that by selective regulation of the needle valves 54, the quantity of fuel consumed in any individual heater unit and the resultant liberated thermal units can be varied at will. By means yof the valves 54 those heaters at 'greatest dis for example a pressure of seventy pounds at 'le Il.

Ato hydraulic frictionv of the fuel liquid within the distributing pipe system. When the liquid fuel under pressure reaches vone of the needle valves 54 and passes therethrough, its pressure is reduced. In accordance with the physical properties of this type of liquid fuel, it is gasified as it leaves the needle valve, and as a gas enters the cylinder chamber 5B. Here it exerts pressure upon the piston 59 which begins to move upwardly. Gas leaks by the piston or passes through the groove 59a into the upper cylinder chamber 58h and thence by the pilot tubing 64 to the pilot cup 10, where it is mixed with air and is jetted upwardly. As the piston 59 moves upward, it operates the arm 89 which, by the train of devices heretofore described, generates igniting sparks adjacent the pilot jet of gas. In the meantime the piston 59 has uncovered the port 62,.and fuel gas passes from the chamber 58 through the bore 51, elbow 55, fitting 32, pipe section 33, bore 35, bore 40, preheater 4|, pipe section 43, bore 38, to the nozzle 39, from which it issues in a jet of high velocity. This fuel jet is ignited by the pilot flame issuing up- Wardly from the pilot tubing 64 and then enters the intake hood 21.

As it streams rapidly into the hood 21 and mixing cylinder I9, air is drawn in through the annular gap between the nozzle 39 and hood 21, and is carried along with the fuel jet into the mixing chamber within the mixing cylinder I9. This air is sufficient for complete combustion. No soot, smoke, or other unburned products are blown from the heater, but we provide the flue with louvers I5 to supply a substantial excess of air as has been heretofore described. The prinl cipal purpose, fulfllled by these louvers and the openings 23 in the end Wall 22 of the flue, is

that of mixing a substantial excess of air with P: 1/2V2D wherein V equals the velocity, D the density of the fluid and P the amount of reduced pressure, so that, 1/2 the velocity squared times the density gives P, the amount of reduced pressure.

As the liquid fuel expands and vaporizes upon entering the cylinder chamber 58, heat of vaporization is supplied from surrounding bodies and atmosphere, greatly reducing their temperature and that of the gas itself. This refrigerating effect is partly overcome after the heater is in normal operation by the radiation and conduction-of heat from the burner flame. To assist in offsetting this refrigerating effect, and to ensure complete gasification of any liquid droplets,'we provide the pre-heater 4| which is interposed in the path of the fuel to the nozzle effect is produced inside saidmtubular member n which has the property of increasing the axial 'velocity flow of heated air from the open end of It will be observed that the heaters Acreate a focused movement of hot air in any desired horizontal direction. These horizontal streams of\hot ir mingle with and raise the temperature ofatd'ie lowermost stratum of air in the orchard, which, because of" its resultant decrease indcnsity, begins a gentle upward movement. Gradually the entire layer of air below the ceiling of the upper layer of warmer air, which is above the danger point, is itselil brought up to a safe temperature. Not until all areas of this cold lower layer are warmed to the ceiling tempera-ture can any of the air streaming from the heaters pierce the ceiling with resultant loss of unused thermal units.. Were the heaters to discharge their hot gases vertically upward, instead of horizontally as practiced by our invention, the lower stratum below the ceiling would have spotted areas of .hot air over theheaters, and relatively cooler areas therebetween, with the result that the air in the heated areas would penetrate the ceiling and be ineffective in Warming the air around the trees, and this penetration of the ceiling would occur before the entire ground layer was brought up to the safety temperature. We consequently conserve all the heat units potentially present in the fuel, first by completely burning it, and then by mixing it with cool air in the iiue and discharging it horizontally at a high velocity in focused fashion in large streams of relatively low temperature.

While We have described one method of igniting the burner in our heater, we do not limit ourselves to this one method of practicing our invention. Lighting of the burner may be` effected by a remotely controlled electric spark, or by making provision for the generation of flame temperatures adjacent the burner jet by chemical means such as the adsorption of the .fuel gas by metals or other materials when the fuel gas reaches the heater.

We desire not to limit the scope of our inven-'` tion to any particular form or embodiment thereof which may have been described above, but have defined it in the following claims.

We claim as our invention: p l. An orchard heater for heating and moving large volumes of heated air horizontally along the ground to intermingle with the cool atmosphere around the trees and warm the same, comprising an elongated circular tubular member substantially completely closed at one end and open at the other, openingsin the wall of said tubular 4member in somewhat spaced relation and extending from one end to the other thereof, means for storing a supply of fuel under pressure and conveying said fuel to orchard heaters distributed about .an orchard, means in said tubular member for burning said fuel movement of the products of combustion thereof.

drawing atmospheric air inside said tubular member to support combustion and excess air to cool the heat of combustion and to cool the Wall of said tubular member so that an injector said tubular member, said large volume of heated air spreading out near the ground and warming the atmospheric air around and in the trees of the orchard.`

2. An orchard heater for heating and moving large volumes of heated air horizontally along the ground around and adjacent the trees to intermingle with the cool ground air and warm the same comprising a round straight elongated tubular member located in a horizontal position near the ground with one end substantially completely closed and the other end open, louvres in the wall of said tubular member in somewhat spaced relation and extending from one end to the other of said tubular member, a source of fuel supply and means for leading fuel to said tubular member, burner means at the closed end of said tubular member to consume said fuel the burning thereof drawing atmospheric air much in excess of that needed to support combustion through the said louvres in the wall of said tubular member said air tending to support combustion and .the excess thereof tending to cool said products of combustion and the Wall of said tubular member which produces an injector effect inside ofsaid tubular member which increases `-the 'velocity flow of heated air passing through and out of said tubular member which large volume of heated air intermingles with the cold air around the ground and the lower parts of the trees and quickly raises the temperature thereof to a` safety point.' f

3.1An orchard heater for heating and moving large volumes of heated air horizontally along the ground and adjacent the trees tointermingle with the cool ground air and warmzthesame, comprising an elongated tubular member located in a horizontal position nearthe'ground one end of which is `substantially completelyV l'closed and the other open, louvres in ther Wallvof said tubular member, a source of fuelsupply and means for conveying it to `said tubular member, a means at the closed end of said tubular member for consuming said fuel, the sizeof said tubular member relative to the size of the flame produced in said tubular member being such that air much in excess of that needed for combustion is drawn inside said tubular member by the burning of said fuel which air acts to supeffect is produced inside said tubular member which has the' eiect of greatly increasing the velocity flow of 'heated air from the open end of said tubular member, no flame of combustion appearing at the open end of said tubular member or popping out of said louvres.

vWALTER A. LEA. EARL VINCENT EHRHARDI'.

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