US2522935A

US2522935A - Radiant heater for preventing frost damage to plant life

Info

Publication number: US2522935A
Application number: US787174A
Authority: US
Inventors: Arthur W Farrall
Original assignee: STATE BOARD OF AGRICULTURE
Current assignee: STATE BOARD OF AGRICULTURE
Priority date: 1947-11-20
Filing date: 1947-11-20
Publication date: 1950-09-19
Anticipated expiration: 1967-09-19

Description

Sept. 19, 1950 A.'W. FARRALL 2,522,935

RADIANT HEATER FOR PREVENTING FROST DAMAGE TO PLANT LIFE Filed Nov. 20, 1947 2 Sheets-Sheet l INVENTOR. ArThur W. Farrell.

ATTORNEY Sept. 19, 1950 A. W.'FARRALL RADIANT HEATER FOR PREVENTING FROST DAMAGE TO PLANT LIFE 2 Sheets-Sheet 2 Filed Nov. 20, 1947 INVENTOR. Ar'rhur w. Farrell.-

BY Mf ATTORNEY Patented Sept. 19, 1950 UNITED STATES PATENT OFFICE RADIANT HEATER FOR PREVENTING FROST DAMAGE TO PLANT LIFE Application November 20, 1947, Serial No. 787,174

6 Claims.

This invention relates to apparatus for preventing the formation of frost by means of radiant heat.

The present invention constitutes an improvement on the invention disclosed in my copending application for Letters Patent Serial No. 715,512, filed December 11, 1946.

The principal object of the present invention is to provide a highly efficient radiant type heater of relatively great heating capacity.

Another object of the invention is to provide a heater of the radiant type constructed in such a manner that a relatively large percentage of heat therefrom is directed toward the perimeter of the plot to be protected from frost.

A still further object of the invention is to provide a heater having reflecting means thereon which is adjustable to distribute the heat to best advantage within the area to be protected from frost.

These objects and others ancillary thereto will more fully appear in the following description, when read in connection with the accompanying drawings, wherein:

Figure 1 is an elevational view partially in section of a heater embodying the present invention;

Figure 2 is a plan view of the same, parts being broken away to more clearly disclose the construction thereof;

Figure 3 is an elevational view partly in section of another form of heater embodying the present invention;

Figure 4 is a plan view thereof; and

Figure 5 is a fragmentary cross-sectional view taken on substantially the line 5-5 of Figure 4.

Referring now more particularly to the drawings, and especially to Figures 1 and 2 thereof, the invention is shown as embodied in a radiant type heater comprising generally a tubular heat exchanger it having a burner l I mounted at the lower end thereof, a reflector l2 and supporting means i3.

The tubular heat exchanger comprises a side wall having a lower portion I4 of generally frusto-conical form converging downwardly. The side wall also has an upper frusto-conical section I5 converging upwardly. The two portions it and 55 may be made in one piece or separately, as desired. If made in two pieces the larger ends, or bases, of the two portions are preferably welded together about their entire peripheries. At the upper end of the upper portion it of the side wall is a stack 16. The stack is need not be particularly high, for it is pro-- ill " supporting frame 22.

vided more for supporting the reflector I2, as will be more fully pointed out hereinafter, than it is for carrying away the products of combustion. Mounted inside of the stack 16 are two

cross pieces

51 and 18, preferably at right angles to each other and in spaced apart relation, which support a rod I9 at the lower end of which is a baflie 20.

At the lower end of the heat exchanger I0 is a bottom plate 22 having a central opening therein. The bottom plate 2| is rigidly connected to the lower portion E4 of the side wall. A suitable supporting frame 22 is suspended from the plate 2!. The burner H is mounted upon the The burner H may be of any suitable character that will provide the necessary heat units.

Preferably the parts of the heat exchanger just described, namely, the side wall, stack and bottom plate, are formed from aluminized" sheet steel. Sheets of steel are covered with a thin coating of aluminum which is melted and flowed on the steel sheets. The coating of aluminum resists oxidation of the steel, permitting the heat exchanger to be heated to temperatures higher than usual, thus increasing the output of radiant heat.

The reflector is a relatively large annular plate, preferably formed from polished aluminum. The reflector '2 has a central opening which receives the stack [6. Preferably the diameter of the opening in the plate 12 is slightly larger than the diameter of the stack to prevent direct contact between the stack and reflector. The reflector will not then be damaged by the hot stack. The inner perimeter of the reflector is supported by brackets l-oa attached to the stack. As has been mentioned previously, the plate I2 is quite large and is relativel thin and flexible. In order to support the reflector H2 at its outer perimeter, four links 23 are provided. These links are connected by means of brackets 24 at uniformly spaced points about the outer periphery of the reflector l2. The links 23 are connected at their inner ends to eyes 25 mounted on a collar 26 secured to the upper end of the stack IS.

The reflector I2 is preferably in the form of a relatively flat frustum of a cone. In the particular form of the invention shown in Figures 1 and 2 the conical surface of the reflector is inclined at an angle of approximately 5 to the horizontal. This angle may be varied, if desired, by providing adjusting means in the of turnbuckles 2'? in the links 23. By taking up or loosening the turnbuckles 21 the shape of the cone may be varied. The particular inclination of the reflector depends upon the distance that it is desired to direct the heat rays from the heater. It may be desired to incline the reflector outwardly and upwardly in certain instances.

The heater shown may be supported upon any suitable framework. It is desirable that the heater be raised a substantial distance above the surface of the ground. The supports shown comprise three legs 28 removably mounted in sockets within brackets 29. The brackets 29 are rigidly attached to the bottom plate 2| of the heater. The lower ends of the legs 23 can be forced into the ground and, if desired, the possibility of the heater being accidentally overturned may be prevented by plates 30 which are pegged to the ground by means of wooden or metal pegs 3| extending through the plates. The plates are provided with holes therein which receive the lower ends of the legs 28.

The heater is utilized to protect the plants within a predetermined area by being located centrally thereof. Whenthe burner H is operated, heat is radiated from the side wall of the heat exchanger. Most of the heat radiates outwardly from the heat exchanger in a direction perpendicular to the side wall thereof. Thus, the heat rays emanating from the lower portion M are distributed outwardly along the broken lines extending therefrom inFigure 1. The heat rays from the upper portion |5 are radiated upwardly and outwardly toward the reflector I2 by which they are reflected outwardly and downwardly. By means of the direct heat rays from the lower portion l4 and the reflected rays from the upper portion, the bulk of the heat radiated from the heat exchanger will be directed out toward the perimeter of the plot which it is desired to protect. It is this portion of the plot which is the most difiicult to furnish protection to, and

'by means of the particular shape of the heater disclosed that protection is afforded. The part of the plot closely adjacent to the heater will be heated by means of radiant heat from the bottom of the heat exchanger, from the burner itself, and from stray heat rays from the side walls. The form of the invention shown in Figures 3 to 5 embodies that feature of the previous modification wherein the bulk of the heat rays are directed from the heat exchanger itself outwardly and upwardly and are then turned downwardly and outwardly by means of reflectors. In this form of the invention there are a plurality of frusto-conical sections all converging upwardly to a plurality of reflectors.

In the form of the invention shown in these figures a heat exchanger 55 is provided with a tubular side wall comprising six frusto-conical sections 5|, 52, 53, 54, 55 and 56. All of these sections converge upwardly. The upper ends of the sections 5| to 54 are joined to the lower ends of the respective sections thereabove by means of annular rings 57. The outer peripheries of the rings 51 are welded to the lower ends of the sections immediately thereabove. The inner peripheach lower baflie is smaller than the one next above it.

The side wall of the heat exchanger is mounted upon a bottom plate 60 having a central opening therein which receives a burner 6|. The bottom wall 60 is supported upon a suitable framework. In the form of the invention shown, the framework comprises four downwardly extending tubes 62 rigidly connected to the bottom plate. The tubes 62 receive upstanding legs 63 connected to a sled-like frame 64, the character of which is clearly evident in the drawings. Preferably the legs 62 have uniformly spaced openings 65 therein which receive pins- 66 that support the lower ends of the tube' 62. By varying the positions of the pins 66 in the different holes 65 the height of the burner above the ground can be adjusted.

The burner 6| is supported on a suitable framework 61' connected to the tube 62.

Thin aluminum reflectors 68 are connected to the side walls of the heater adjacent the lower ends of eachof the sections 52 to 56. The formation of the reflectors and the manner of attachment to the side wall of the heat exchanger is shown in detail in Figure 5. The inner periphery of each reflector 68 is provided with a bead 69. The bead rests upon a rod 10 bent into circular form and welded to an outturned flange H at the lower end of each of the sections 52 to The flange 7| and rod 10 hold the reflector away from the extremely hot surface of the ad- ,spaced points, by a U-shaped yoke 14. The yoke "Mmay-be bolted to the reflector by bolts 15. On

each yoke 74 a small ring 16 is attached. The side of the ring is provided with a tapped opening receiving aset screw 11. The rings 15 receive four uprights 18 which are firmly attached to a supporting framework of the heater by means of struts .19 and 80.

The reflectors 68 are preferably in the form of shallow frustums of cones. The inclination of the conical surfaces may be adjusted by loosening the set screws 11 and sliding the rings 18- up or down to the desired position where they are again clamped by the set screws.

In the form of the invention shown in Figures 3 we most of the heat radiated from the side wall of the heater is directed outwardly and upwardly from the sections 5| to 55. When the radiant heat rays strike the reflectors E8 the rays are directed outwardly and downwardly toward the plot to be protected. Some heat is radiated to the ground directly from the annular rings 51, from the bottom plate '60, and from the burner itself. These rays will suffice to protect the area closely adjacent to the burner while the reflected rays are distributed out toward the periphery of the plot.

In both forms of the invention the flames from the burner are deflected outwardly against the side walls of the heat exchanger by the

battles

20 and 59. Thus, the heat produced in the burner is efficiently utilized to provide radiant heat.

It will be noted that in both forms of the invention reliance for protection of the perimeter of the plot is placed principally upon the rays emanating from the upwardly converging sections of the burner side wall which are reflected 1 by the reflectors l2 and 68. It has been found that heaters of this character are particularly efficient in forcing the heat out toward the perimeter of the plot where it is particularly desired.

It has been found that heaters of this type are capable of protecting quite large areas from frost. The heat supplied in the form of radiant heat rays to the outer portions of the plot is quite uniformly distributed. Both types of heaters have protected relatively tender plant life against any damage due to frost to a distance of 120 feet from the heater when the temperature an inch above the ground reached 26.4.

Thus, it will be seen that the present invention provides an extremely efiicient radiant type heater. It is relatively simple to manufacture.

The scope of the invention is indicated in the appended claims.

I claim:

1. Combustion apparatus for heating by means of infra-red rays an unenclosed area many times the horizontal extent of said combustion apparatus comprising a heat exchanger having a tubular side wall, said side wall comprising a first frusto-conical portion tapering inwardly and downwardly and a second frusto-conical portion adjoining the upper extremity of said first portion and tapering inwardly and upwardly therefrom, and a relatively wide annular reflector plate mounted above the second frustoconical portion and substantially transverse to the axis thereof, the reflector plate and the second frusto-conical portion being arranged at such a relative angle to each other that substantially all rays normal to the conical portion strike said plate and are reflected and directed outwardly beyond the outer confines of any area beneath said plate.

2. Combustion apparatus for heating by means of infrared rays an unenclosed area many times the horizontal extent of said combustion apparatus comprising a heat exchanger having a tubular side wall, said side wall comprising two frusto-conical portions having vertical axes and with their bases joined together, and a relatively wide annular reflector plate above the upper frusto-conical portion and connected at its inner periphery to said side wall, said refiector plate extending substantially transverse to the axis of said tubular side wall and being arranged at such a relative angle to the upper irusto-conical portion that substantially all rays normal to the conical portion strike said plate and are reflected and directed outwardly beyond the outer confines of any area beneath said plate.

3. Combustion apparatus for heating by means of infrared rays an unenclosed area many times the horizontal extent of said combustion apparatus comprising a heat exchanger having a tubular side wall, said side wall having a portion thereof tapering upwardly and inwardly, and a relatively wide annular reflector plate mounted above said tapered portion and substantially transverse to the axis thereof, the reflector plate and the tapered portion being arranged at such a relative angle to each other that substantially all rays normal to the conical portion strike said plate and are reflected and directed outwardly beyond the outer confines of any area beneath said plate.

4. Combustion apparatus as defined in claim 3 wherein means are connected to said heat exchanger and the outer perimeter of said reflector plate for partially supporting the latter.

5. Combustion apparatus as defined in claim 3 wherein means are connected to said heat exchanger and the outer perimeter of said reflector plate for partially supporting the latter, said means being adjustable whereby to regulate the position of the reflector plate relative to the heat exchanger.

6. Combustion apparatus as defined in claim 3 wherein said side wall is formed from sheets of ferrous metal coated with aluminum.

ARTHUR W. FARRALL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,553,922 Aram Sept. 15, 1925 1,658,690 Sanctuary et al. Feb. 7, 1928 1,680,005 Bevier Aug. 7, 1928 1,749,710 Maddalena Mar. 4, 1930 1,767,670 Huff June 24, 1930 2,133,649 Abbot Oct. 18, 1938