US2652888A - Burner and igniter structure - Google Patents

Description

Sept. 22, 1953 e. w. ALLEN ETAL; 2,652,888

BURNER AND IGNITER STRUCTURE Original Filed June 14, 1946 2 Sheets-Sheet 1 N i 1, Hr,

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BURNER AND IGNITER STRUCTURE Original Filed June 14, 1946 2 Sheets-Sheet 2 32 III"! I w. I M. i j 30 rill I l ywaws m AA-W/ 0 Patented Sept. 22, 1953 BURNER AND IGNITER STRUCTURE George W. Allen, Indianapolis, Ind., and Vernon N. Tramontini, Los Angeles, Calif., assignors to Stewart-Warner Corporation,

corporation of Virginia Original application Jun 676,776, now Patent N Chicago, 111., a

e 14, 1946, Serial No. 2,507,081, dated May 9, 1950. Divided and this application February 25, 1948, Serial No. 1Q,624

3 Claims.

The present invention relates to heaters generally and more especially to a burner for the sealed type of internal combustion heater designed for use in aircraft, small boats, automobiles, and the like. The present application is a division of our copending application Serial No. 676,776, now Patent No. 2,507,081.

The structure shown and described herein is particularly intended for use in automobiles, and one object of the invention is to provide a burner for a heater of compact form having its essential parts closely associated in a single assembly adapted to be readily installed, preferably under the engine hood of the vehicle.

Another object of the invention is to provide a structure for the purpose indicated, so designed as to be economical to manufacture with the parts arranged conveniently for making welded joints where gas-tight connections are important.

It is also an object of the invention to provide an internal combustion heater in which the pipe through which air is supplied for combustion passes through the combustion chamber for preheating the air, and in which the air is discharged from said pipe into a partitioned portion of a burner space to insure thorough admixture of the air with the vaporized liquid fuel.

More specifically it is an object of the invention to provide an internal combustion heater liquid fuel burner having improved starting and operating characteristics, which operates efficiently and reliably throughout a wide range of heat output and which can be manufactured in production quantities at low cost.

Other objects and advantages, including specific features of construction designed to facilitate economical manufacture, will appear more fully from the following description taken in connection with the drawings, in which:

Fig. l is a longitudinal vertical sectional view of a heater embodying this invention except that a portion of one end of the heater is left in elevation and adjacent portions are shown broken away to illustrate certain details of the structure;

Fig. 2 is a horizontal sectional view of a portion of the heater taken as indicated at line 2-2 of Fig. 1; and

Fig. 3 is a fragmentary detail sectional view taken as indicated along the line 3-3 of Fig. 1.

As seen in Fig. 1, the heater to which this invention relates includes an outer cylindrical casing ill upon which there is mounted a blower, not shown, for furnishing air for combustion to the heater. Leading from the blower there 2 is shown an air pipe Hi bent to enter the interior of the heater through an opening in the casing l0, while an exhaust pipe 2d for products of combustion extends from the lower portion of the casing.

The interior structure comprises a plurality of coaxially disposed cylinders or sleeves. The innermost cylinder 26 forms the combustion chamber of the heater, and the burner mounted at one end of this cylinder includes a frustoconical shell 23 having at its base or larger end a cylindrical flange which is fitted into the end of the cylinder 26 and closed by a flanged end wall 30. The overlapping flanges of the members 28 and 33 and the cylinder 25 thus terminate substantially in a plane whereby the closely fitting ends may be easily welded together. A small chamber or pocket 32 is secured in a flanged opening in the end wall 39 and supports the electrically energized igniter which includes a tubular casing 34 open at one end, with a heater coil 36 of resistance wire arranged coaxially therein. The igniter tube 34 has its axis horizontally disposed in the pocket 32 so that liquid fuel fed from the valve device through a feed pipe 38 flows or drips downwardly on to the upper side of the hot tube 34 and a considerable portion of the fuel is thus vaporized. The remainder flows around the surface of the igniter tube 34 on to an absorbent mat or wick to composed of fine wire in woven or braided form so that the liquid entrapped therein is readily vaporized by heat radiated from the igniter and from the burning fuel in adjacent portions of the burner. Battles 33, extending from the side walls of the pocket 32, serve to hold the mat to in place, while permitting any excess of unvaporized fuel to flow between them along the bottom of the pocket 32 and into the adjacent part of the burner shell 28.

The air for combustion flows through the curved pipe It which enters the outer casing Iii as already described, and extends through the coaxial cylindrical elements of the heater for discharging air into the frustoconical shell 28. A portion I ia extends horizontally within the combustion chamber 26 toward the burner and terminates in an elbow I :ib, which discharges downwardly just below the horizontal plane of the axis of the burner shell 28. The pocket 32, in which the liquid fuel is vaporized, is also located below this axis, and opposite said pocket 32 the conical burner shell 28 is provided with a vertically disposed baflle wall 56 which is of semicircular outline as seen in Fig. 3, with its straight upper edge located substantially at the axis of the shell 28. This upper edge of the bafile 56 is just above the discharge opening of the elbow 54b and the elbow is located against the curved wall of the shell 28 so. that air is discharged from the elbow in substantially tangential relation to this curved wall and downs wardly adjacent the open side of the pocket 32. This insures that the vaporized fuel will be picked up by the warm air issuing. from, the elbow U11).

and will become thoroughly intermixed there.-

with as the air sweeps around the: interior of the frustoconical shell 28; and any liquid fuel which may flow from the pocket 32 into the lowest part of the shell 28 will. be quickly'vapor rized by contact with this. warm air sweeping over it. The combustible mixture is initially i'gnited by the hot wire 36 and the flame is propagated through the mixture and discharged: from the smaller end of the shell 28 into the combustion chamber formed by the inner sleeve or cylinder' 26,. At: its opposite; end the cylinder 2-5 is closed by an end wall, not shown.

The. next adjacent: sleeve or cylinder 54 is spaced from the sleeve 26 to form a passage 55 of; annular cross'section openfrom end to end for the. flow; of ventilating air-to be heated. When the. heater is installed in. an automobile, a fan or blower, not shown, will usually'be connected at oneend or the, other of the casing 1-0 to insure the flow of. this ventilating air: through the. passage 55 and into the body'of thevehicle for warming: the drivers: space, orboth. In the heater structure asshown, a third sleeve or-cylinder 56 is, spaced around the sleeve A and within the cylindercasing in in spaced relation to the latter; so that a second annular passage 51 for ventilating air is provided between the casing is and the cylinder 56. The space 59' between the sleeves 54- and 55' is placed in communication with the combustion chamber to receive the products of combustion flowing therefrom and to distribute; thesehot gases over the surfaces of the sleeves 54 and 56 in heat exchange relation with the ventilating air flowing through, the spaces 55 and 51. These hot gases are then conducted away through theexhaust pipe shown at 24.

The connection between the combustion chamber within the cylinder 26 and the space 59 is,

formed by a longitudinallyextending slot 66 in the cylinder 26 which is disposed in registration withv a similar longitudinal slot in the sleeve 5%. As seen in Fig. 4, the material of the sleeve 51 which forms the margin of the slot 6.3.is offset inwardly. at 62 by an amount equal to the radial width of the space 55, bringing this marginal area 62 into contact with the outer'face of the cylinder 26. These contacting surfaces are electrically seam welded, thus forming a gas-tight joint between the two sleeves around the opening formed at the slot 66. Thi opening provides communication between the combustion chamber and the.

space. 59 substantially throughout the length of theheater. Thus, the hot gases of combustion discharged from the burner space, in the shell 28 toward the opposite end of the combustion chamber fill the chamber and then flow through the opening 66 and distribute themselves in both directions circumferentially through they space 59 toward the exhaust pipe 24 which, as shown, is disposed diametrically opposite the. opening formed by the slot 60.

The sleeve 56 is; spaced from the sleeve. 54 by the provision of rings 66 to. serveas end closures compartment, or the passengerfor the space 59 formed between these two sleeves. As shown, these rings telescope within the respective end portions of the sleeve 56 as at 65 and are offset inwardly to fit snugly around the end portions of the sleeve 54. at61 so that both joints may be conveniently made by seam welding, the rings being first welded to the ends of the sleeve 56 and then fitted over the end portions of the sleeve- 5li and welded thereto. This provides a gas-tight connection between the sleeves 54 and 56; at bothendsof the space 59. The outer casing tilj is preferably made in two parts connected by longitudinallock seams i6 and H to facilitate assembly.

The automatic operation of the heater may be controlled bysuitable devices arranged in an electrical circuit, such as that shown and described in the previously referred to copending application.

In operation, the igniter is energized and the fuel is turned on either simultaneously or subsequently thereto, the fuel being delivered through the pipeSfi. customarily, this is accomplished by energizing a magnetic fuel valve in the.

line 38. at. the sametime the igniter is energized.

through the pipe [4, Ma and elbow [4b so that.

the combustion air passes, into the combustion chamber in a. position between. the end wall 30. andv the baiile. 56.

They fuel vapor which boils ofi the hot sleeve 34. is mixed with combustion air which eddies into the pocket. 32 from the combustion chamber and the fuel and air mixture thus formed is ignited by the hot. coil 36.. This forms a small flame. which ignites the mixture of fuel and air within the main combustion chamber almost im-- mediately unless the temperature is extremely low in which case an appreciable interval of burning within the pocket. 32 may take place. before the, combustion chamber is. brought to, such a temperature that combustion can be maintained therein. Once combustion is. well established in the main combustion chamber, very little burning will continue to take place within the pocket 32. since the mixture therein will be too rich to burn. This is because, as. the pocket warms up, a larger portion of the fuel passing therethrough will be vaporized within the pocket while simultaneously, inasmuch as combustion is taking place within the main combustion chamber, there will be less oxygen in the gases by the time these gases reach the bottom of the combustion chamber where the opening to the pocket 32 is located.

Inasmuch assubstantially all of the combustion, takes place within the main combustion chamber the pocket 32 cools suihciently to insure a long life for the igniter which is customarily de-energizezias soon as combustion has been well established. During the period while combustion is taking place in the main chamber the major portion of the fuel flowing from the pipe, 38 will pass across the bottom of the pocket 32 and into the main combustion chamber, the

wick 46 helping to distribute the fuel somewhat.

more evenly. The air sweeping over the liquid fuel at the lower side of the combustion chamher and mixing with some vaporized fuel issuing from the pocket 32 produces a mixture of fuel and air which burns with good efliciency and supplies hot gases to the heat exchange portion of the device. These hot products of combustion pass over the section Ma or" the air pipe and raise its temperature, thereby preheating the combustion air. This is an aid in promoting stable and efficient operation of the device as well as enabling larger quantities of fuel to be burned within a combustion chamber of any particular size than would otherwise be practical.

While there is shown and described herein certain structure embodying the invention and illustrative thereof, it is to be understood that the invention is not limited thereto or thereby, but embraces all modifications, variations and equivalents thereof which come within the scope of the appended claims.

We claim:

1. In an internal combustion heater, a burner structure comprising a frusto-conical shell having a horizontal axis and open at its smaller end, a flat wall closing the larger end of said shell, a pocket in said wall opening into the lower portion of said shell, means to supply liquid fuel to said pocket, means to vaporize and ignite said fuel, a combustion air supply pipe discharging tangentially into the burner shell in a downward direction adjacent said flat end wall, and a vertical baflle wall extending across the lower portion of said shell in spaced relation to said end wall, the discharge end of said air supply pipe being between the end wall and the bafiie wall, whereby the air flow is initially confined to the vicinity of said pocket opening to facilitate admixture of the air with the fuel.

2. In a heater as defined in claim 1, said air supply pipe comprising an elbow at its discharge end with a horizontally extending portion leading thereto through the upper portion of the burner shell in the path of the flame which 6 advances over said bafile wall and through the smaller end of the shell, whereby the incoming air is preheated.

3. In an internal combustion heater, a burner structure comprising a shell having a horizontal axis and open at one end, a wall closing the other end of said shell, a pocket in said wall opening toward the space in the shell, means for supplying combustion air into said space, a conduit for liquid fuel having a delivery outlet in the upper part of said pocket, an igniter which includes an internally heated tubular shell, said igniter being mounted in a vertical wall of said pocket with said tubular shell extending horizontally under said fuel delivery outlet for vaporizing the fuel as it strikes said heated shell, the bottom of the pocket sloping downwardly toward the opening which leads into the burner shell, an absorbent mat disposed beneath said tubular shell, and bailies extending inwardly from the side walls of the pocket engaging portions of said mat to retain it in the pocket but leaving space between them for drainage of liquid fuel over the sloping bottom into the burner shell.

GEORGl-"Z JV. ALLEN. VERNON N. TRAMONTINI.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,382,721 Gerstenberger June 28, 1921 1,903,364 Grant et al. Apr. 4, 1933 2,307,007 Alain Jan. 5, 1943 2,411,040 I-Iolthouse Nov. 12, 1946 2,420,757 Neumann et a1. May 20, 1947 2,421,370 Budlane June 3, 1947 2,424,765 McCollum July 29, 1947 2,481,631 Tramontini Sept. 13, 1949 2,489,716 McCollum Nov. 29, 1949 FOREIGN PATENTS Number Country Date 38,126 France Jan. 7, 1931

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