US3258002A - Heater unit - Google Patents

Description

June 28, 1966 A. 'r. RACE, JR 3,258,002

HEATER UNIT Filed July 23, 1964 2 Sheets-Sheet l 1N VENTOR Aus-nNT. RHCEJIR.

ATTORNEYS June 28, 1966 A. T. RACE, JR

HEATER UNIT 2 Sheets-Sheet 2 Filed July 23, 1964 INVENTOR Aus-rm T Race 39..

BY (LSMFPMJ %d cwnmed ATTORNEYS United States Patent 3,258,002 HEATER UNIT Austin T. Race, .lr., Winter Haven, Fla. Filed July 23, 1964, Ser. No. 384,698 9 Claims. (Cl. 12659.5)

This invention relates to heaters, and particularly to heaters of a type suitable for orchard, grove, and farm use, especially in areas where smokeless heaters must be used.

One known practice in orchard, grove, or farm heating to protect fruit-bearing trees, plants, etc. from freeze damage, is the use of a gun, or tube, type burner to throw a flame horizontally adjacent the ground to provide heat for mixture with the surrounding air. A metal shell is sometimes used with the burner so that the shell will be heated to incandescence and provide radiant heat to protect trees in the surrounding area. While this practice provides good heating so long as the burners function perfectly, some difficulties have been encountered in maintaining a proper burner flame due to carbon deposits being picked up by the velocity of the produced gaseous vapor and lodging in the nozzle orifice, some tendency toward back flow in the feed line because of heat and pressure in the line created by pre-heating the fuel, and misalignment or improper position of the burner tip with respect to the pre-heating coil in those burners where the fuel line is coiled within the burner tube and the burner flame is directed through the coil to preheat the fuel. These factors can cause the flame to burn at a lesser rate which may cause flame fluctuation and flameout, and hot spots in the preheater may cause the flame to pulsate.

It is the general object of the present invention to provide an improved burner which will not be subject to the difficulties mentioned above, but will burn with a steady flame at all recommended operating pressures with little or no attention.

A more specific object of the invention is to provide means to prevent carbon formed in the preheater coil, or other parts of the feed line, from reaching the burner nozzle.

Another object is the provision of means to retard back-flow in the fuel feed line from heat and pressures.

Still another object is to provide for adjustment of the burner to correct for misalignment of the nozzle relative to the preheating coil, and to vary slightly the spacing of the nozzle from the coil.

Other objects of the invention will become apparent from the following description of one practical embodiment thereof, when taken in the light of the drawings, which accompany, and form part of, this specification.

In the drawings:

FIGURE 1 is a perspective view of a burner incorporating the principles of the present invention, the burner being shown with a shell which may be used for producing radiant heat;

FIGURE 2 is a vertical, longitudinal section through the burner shown in FIGURE 1, taken on the line 22 of FIGURE 1;

FIGURE 3 is a vertical, transverse section through the burner, taken on the line 3-3 of FIGURE 2;

FIGURE 4 is another vertical, transverse section, taken on the line 44 of FIGURE 2;

FIGURE 5 is a section through a back-flow arrester inserted in the burner fuel feed line, taken on the line 5-5 of FIGURE 2;

FIGURE 6 is a perspective view of the burner head carrying the burner nozzle;

FIGURE 7 is an exploded perspective view of the components of the burner head; and

FIGURE 8 is a longitudinal section, on an enlarged scale, through the burner head.

The heating unit shown in the drawings consists in a gun, or tube, type burner l. A shell 2, which may be used with the burner when it is desired to supply radiant heat, is shown as a cone of sheet metal, having an open bottom 3. A relatively large opening 4 is provided in the side, through which flame from the burner may enter to heat the metal shell. Other smaller openings 5 are present through the surface of the cone to permit the escape of gases. In operating the burner and shell combination, the shell is placed on the ground, spaced from the outlet end of the burner, with the opening 4 generally aligned with the longitudinal axis of the burner tube. Flame, as shown at 6, from the burner enters the shell through opening 4 and impinges on the shell wall interior, some flame and the gases of combustion passing out through openings 5. The heat of the flame causes the shell to become incandescent, and heat will radiate outward and upward from the shell.

The above described unit makes a very effective grove heater where radiant heat is desired. The shell throws oft a great amount of radiant heat, the entire unit is very light weight and easily portable, and the radiant shell can be replaced when required without replacing the entire unit. In most instances, however, the burner is used alone as a source of convection heat.

The burner 1 has a tray-like base 7, upon which a housing 8 is mounted. The housing 8 has a top 9 of cylindrical curvature of more than semi-circular extent to embrace and support a preheating coil 10. The open side of the partial cylinder faces downwardly, and vertical sides llll extend from the cylindrical edges downwardly to the base. Fingers 12, struck out from the sides 11, straddle the base top edges to mount the housing. A back wall 13 bridges the housing and base. The wall 13 has an inlet opening 14- for fuel from the burner nozzle. A plurality of inlets 15 for air to support combustion encircles the fuel inlet.

The preheating coil ltl is located at the forward end of the housing, and is a part of a fuel feed line 16 which has an upper leg 17 that extends from the rearmost convolution of the coil along the top of housing 8, and projects some distance to the rear of the housing and terminates in a coupling 18 for connection to a supply line 19. From the last convolution at the inner end of the coil, the line extends rearwardly as a lower leg 20 through the housing and back wall adjacent the base 7. At the rear of the burner, the bottom leg is bent upwardly from itself to form a forwardly projecting burner head mounting leg 21 on which a burner head 22 is threaded. The heat mounting leg 21 has its axis approximately on the axis of the preheating coil 10.

The lower leg 20 of the fuel line, and the burner head 22 are held against accidental movement from selected positions of adjustment by means of a clamp 23. The clamp comprises a pair of identical castings 24 each having a recess 25 to seat the burner head, and recesses 26 and 27 to seat the upper and lower legs 17 and 2t), respectively, of the fuel line. Bolts 28 between the upper leg 17 of the fuel line and the burner head, and between the burner head and lower leg 20 draw the castings tightly into engagement with the several members they engage to hold these members against movement relative to one another. The upper leg 17 of the fuel line is secured to the burner housing by means of a pipe clamp 54, and acts as the anchor member for the burner head. By clamping the burner head intermediate the upper and lower legs of the fuel line, the head will be held against side movement and at a fixed distance below the upper leg of the fuel line. This permits holding the burner head with its Q3 axis in alignment with the axis of the preheating coil. This assures proper direction of the flame.

It will be noted from FIGURE 2 of the drawings that the last convolution of coil at the inner end is free from the adjacent convolutions and spaced slightly from that convolution. This affords some freedom of adjustment of the burner head to move the nozzle forward or rearward to vary the distance between the nozzle and the inlet orifice 14 in the back wall and the coil 10. Clamp 23 will hold the burner head in selected positions of adjustment.

Burner head 22 is composed of a cylindrical casing 29 having end closures 30 and 31. End closure 30 is welded to the back end of casing 29 and has a central, threaded aperture 32 to screw onto the threaded end of the mounting leg 21 of the fuel line. The cylindrical casing 29 and end closure 30 form a cup, into which is inserted in succession, a pad 33 of fireproof fibers, such as stainless steel, bronze, glass, etc., a first screen 34, a spacer ring 35, a second screen 36, another spacer ring 37 and a third screen 38 to hold the various elements in place in the cup and to close the cup. The screens 34, 36 and 38 may be of bronze or other suitable wire having a mesh much smaller than the nozzle orifice. There is a central threaded aperture 39 in end closure 31 into which a fuel nozzle 40 is screwed. The nozzle has the usual small outlet orifice 41. The inner face 42 of the end closure 31 has an outer annular rim 43 to bear upon screen 38, but the remainder of the face is recessed, as at 44, so that the inner end of the aperture 39 is spaced outwardly from screen 38. A short length of tube 45 is shown pressed into the entrance end of aperture 39 and extending rearwardly through a central opening 46 in screen 38. The tube effectively prevents carbon which may be formed by impingement of fuel on the inner face of end closure 31 from getting into the nozzle. It will be obvious that the tube may be formed as an integral part of the end closure if desired.

Fiber pad 33 will filter much of the carbon from the fuel entering the head, but some will pass through to be stopped by screen 34. Continued use of the burner will cause carbon accumulation on screen 34 to the point where flow through would be virtually stopped if some provision were not made to allow continued flow-through. To this end, screen 34 is provided with a plurality of enlarged openings 47 of a size not likely to become clogged by carbon. With this arrangement when the mesh of screen 34 becomes filled with deposit, fuel with whatever sediment may be left in it may flow freely through openings 47. Screen 36 is of the same mesh as screen 34, but has no enlarged openings. Thus, fuel flowing from screen 34 will be filtered by screen 36. This provides double filter capacity without increasing the diameter of the burner head. Any carbon which may be fomed by contact of the fuel with the metal of tube 4-5 or the nozzle will be in an area of high velocity flow and will be carried out through the nozzle orifice before it can grow to a size to clog the orifice.

With the above described filter arrangement in the burner head, the burner may be used over long periods of time without clogging. The head, in effect, is a filter unit which also serves as a mount for the nozzle, and a means of connection between the nozzle and the fuel line. When a filter unit becomes filled with debris, the head can be unscrewed from the fuel line, the nozzle removed and a new unit substituted.

As previously mentioned, heat and pressure which develop during use of the burner will cause a tendency for backflow in the fuel line with the result that at times there is flow in both directions and a fluctuating flame. To overcome this, the present invention provides a backflow arrester 48 in the upper leg 17 of the fuel line. The arrester is formed by making the leg 17 of the fuel line in two sections having their adjacent ends threaded and coupled together by a threaded sleeve 49. A screen 50 is seated against the end of the upstream section of leg 17, and a plug 51, having a restricted orifice 52 opening into an enlarged open-end chamber 53, is inserted in the adjacent end of the downstream section of the leg. The velocity of the fuel flow through the restricted orifice in the plug effectively retards backflow in the line.

The burner as disclosed herein Will provide long periods of trouble free operation and can be used without frequent checks. It is simple to adjust to maintain the burner nozzle at its proper position, and the filter assembly in the form of a burner head is readily replaceable.

While in the above one practical embodiment of the invention has been disclosed, it will be apparent that the specific details of construction shown and described are merely by way of example, and the invention may take other forms within the scope of the appended claims.

What is claimed is:

1. A heater unit comprising, a shell and a separate burner to heat the shell to give off radiant heat, the shell being a cone of thin metal and having an opening in the side for alignment with the burner, the burner having a nozzle and support means for horizontally positioning the nozzle for alignment with and providing adjustable spacing relative to the opening in the shell, whereby flame from the burner nozzle will enter the opening in the shell to heat the shell and the ratio of radiant heat from the shell and convective heat from the burner can be varied.

2. A heater unit as claimed in claim 1 wherein, the shell has additional openings for the escape of gases.

3. A burner comprising, a base, a housing over the base defining a combustion chamber, a fuel feed line, a burner head including a casing and end closures for the casing defining a filter chamber, the fuel line connected to one end closure of the burner head, a nozzle connected to the other end closure of the burner head, a filter pad in the filter chamber adjacent the end closure to which the fuel line is connected, a first filter screen against the filter pad, a second filter screen spaced from the first in the direction of the nozzle, both said screens being of similar mesh, said first screen having a plurality of enlarged passages there-through, whereby fuel and foreign matter therein may pass through the enlarged openings of the first screen when the mesh of the first screen has become clogged with foreign matter.

4. A burner as claimed in claim 3 wherein, there is a third screen spaced from the second screen and from at least the central portion of the end closure to which the nozzle is connected, the end closure to which the nozzle is connected having a central aperture in which the nozzle is mounted, a tube in the said aperture and projecting through the third screen into the space between the second and third screen.

5. A burner comprising, a base, a housing over the base, a back wall at one end of the housing, the opposite end of the housing being open, a preheating coil in the housing adjacent the open end thereof, a fuel line connected to the ends of the preheating coil whereby the coil is a part of the fuel line, the fuel line having an upper leg extending from the coil along the outside wall of the housing from the open end of the housing to the back wall and beyond, the fuel line having a lower leg extending from the coil through the housing and housing back wall, the lower leg of the fuel line being turned upon itself to provide a burner head leg intermediate the upper and lower legs and substantially in alignment with the central axis of the preheating coil, a burner head connected to the burner head leg, a nozzle mounted on the burner head, means securing the upper fuel line leg to the housing, and a clamp engaging the upper fuel line leg and the burner head to hold the nozzle in alignment with the axis of the preheating coil.

6. A burner as claimed in claim 5 wherein, the clamp also embraces the lower fuel line leg to hold the upper, lower and burner head fuel line legs in a common vertical p ane.

7. A burner as claimed in claim 6 wherein, the clamp includes companion castings having recesses to receive the upper, lower and burner head fuel line legs, and means to draw the castings toward one another in clamping engagement with said fuel line legs.

8. A burner comprising, a base, a housing over the base, a preheating coil in the housing at one end thereof, a nozzle at the opposite end of ethe housing from the coil, a fuel line connecting one end of the coil With the nozzle, a fuel line connected to the opposite end of the coil and extending along the outer surface of the housing and projecting beyond the end of the housing in which the nozzle is located, and a back-flow arrester in the projecting portion of the fuel line, the back flow arrester including a plug seated in the projecting portion of the fuel line, the plug having a restricted orifice therein.

9. A burner as claimed in claim 8 wherein, there is a screen bridging the fuel line upstream of the plug.

References Cited by the Examiner UNITED STATES PATENTS 1,304,045 5/ 1919 Hill. 1,582,621 4/ 1926 Roberts. 2,097,544 11/1937 Ames 126-59.5 2,373,588 4/ 1945 Meiklejohn. 2,463,830 3/1949 Tullis 15853 2,467,450 4/ 1949 Wollner 15 879 FOREIGN PATENTS 1,216,387 11/1959 France.

CHARLES J. MYHRE, Primary Examiner.

Claims (1)

1. A HEATER UNIT COMPRISING, A SHELL AND A SEPARATE BURNER TO HEAT THE SHELL TO GIVE OFF RADIANT HEAT, THE SHELL BEING A CONE OF THIN METAL AND HAVING AN OPENING IN THE SIDE FOR ALIGNMENT WITH THE BURNER, THE BURNER HAVING A NOZZLE AND SUPPORT MEANS FOR HORIZONTALLY POSITIONING THE NOZZLE FOR ALIGNMENT WITH AND PROVIDING ADJUSTABLE SPACING RELATIVE TO THE OPENING IN THE SHELL, WHEREBY FLAME FROM THE BURNER NOZZLE WILL ENTER THE OPENING IN THE SHELL

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