US3229745A - Pot-type liquid fuel burner - Google Patents

Description

Jan. 18, 1966 GQRSKE ETAL 3,229,745

POT-TYPE LIQUID FUEL BURNER Filed Sept. 25, 1963 2 Sheets-Sheet l IIO F I2 I 1]" H z H gNXENTORS Gamma ame LOURDES V. M ARTY Aw-wau x' Jan. 18, 1966 H. A. GORSKE ETAL POT-TYPE LIQUID FUEL BURNER Filed Sept. 25, 1963 2 Sheets-Sheet 2 PR5. Z

INVENTORS' HRM M A GQRSKE N LOURDES v. Mc Comm Ar-roRueY United States Patent 3,229,745 POT-TYPE LIQUID FUEL BURNER Herman A. Gorske and Lourdes V. McCarty, Milwaukee,

Wis., assignors to Controls Company of America, Melrose Park, 11]., a corporation of Delaware Filed Sept. 25, 1963, Ser. No. 311,586 1 Claim. (Cl. 158-4) This invention relates to a pot-type liquid fuel burner in which products of combustion are introduced into the pot with the combustion supporting air.

One object of this invention is to provide an improved pot-type burner in which combustion is so highly eflicient that the burner is always extremely clean and there is no observable soot or smoke in the outlet flue.

Another object of this invention is to provide a burner of this type which has no flame noise apparent over other operating noises.

Still further objects of this invention are to provide a burner of this type which is highly eflicient, inexpensive to manufacture, is readily assembled in a furnace, and requires a minimum of maintenance.

These objects are obtained by employing a pot-type burner into which liquid fuel is supplied in atomized condition, providing means for siphoning part of the products of combustion and introducing such products with the combustion supporting air to the inlets of the pot. Positive fluid moving means introduces a stream of the products of combustion at an area closer to the wall of the pot than the stream of combustion supporting air. As the two streams are combined there will be a high concentration of the products of combustion at the primary inlets in the pot. However, as the combined streams are conveyed to the secondary and tertiary inlets of the pot, the concentration of the products of combustion becomes less. The advantage of this is that within the pot the concentration of the products of combustion will be maintained substantially constant as such loss is made up by the products of combustion created within the pot. This even concentration is believed to contribute to clean burning of the fuel, high efficiency and smokeless operation.

Other objects and advantages will be apparent from the specification and claim and from the following description of a single embodiment of the invention shown in the drawings in which:

FIG. 1 is a schematic view in elevation showing a hot air furnace in which the pot-type burner embodying the present invention is installed;

FIG. 2 is a fragmentary sectional View of the heater casing, combustion chamber, feed chamber and pot of a pot-type burner embodying the present invention;

FIG. 3 is a fragmentary sectional view of the drive motor and fuel pump attached to the bottom of heater casing of FIG. 2;

FIG. 4 is a fragmentary top plan view, partly in section, of the rotor of the fuel pump;

FIG. 5 is a sectional view taken on the line 55 of FIG. 2;

FIG. 6 is a fragmentary top plan view taken from the line 6-6 of FIG. 2 with parts broken away and shown in section to illustrate the construction of the fans for supplying the products of combustion and the combustion supporting air.

Referring to drawings in detail and by reference numbers the pot-type liquid fuel burner embodying the present invention is shown installed in a hot air furnace or space heater 10 of conventional design having a heat transfer chamber 12 through which air is passed and heated for distribution to the space to be warmed.

The burner of this embodiment has a heater casing Patented Jan. 18, 1966 14 which is connected to an outlet flue 16 of standard design. This heater casing is mounted within the furnace in any conventional manner and provides the support for a burner casing 18 which in turn surrounds and supports a pct 20. Standard spacer and screw means 22 hold the burner casing with its bottom and wall spaced from the bottom and wall of the heater casing 14 to form a return passage 24 for the products of combustion. The pot 20 is held by conventional spacers and screw means 26 with its bottom and wall spaced from the bottom and wall of the burner casing 18, in the manner shown in FIG. 2, to form an intake and feed chamber 28, the top of which is closed by an annular flange 29 spanning the space between the pot 20 and the burner casing 18.

The pot 20 has a generally standard design and includes upper and lower flame propagators 30 and 32 spaced vertically as shown and fixed to the wall of the pot. Below these flame propagators is a pan 34 which forms an insulating space with the bottom of the pot so that the atomized liquid fuel will come in contact with the hotter metal of the pan and eliminate formation of carbon deposits. The pan 34 is held spaced from the bottom and sides of the pot by spacer and screw means 36 to permit combustion supporting gases to mix with the atomized fuel and form a combustible mixture. For the purpose of igniting the mixture there is provided a spark igniter 38 of conventional construction which extends into the interior of pan 34. This igniter will start combustion every time the thermostat controlling the unit calls for heat. In this respect this pot-type burner operates :on the same principle as a gun-type burner. It is either in full operation or it is off and combustion commences each time the burner is started and the spark igniter energized.

In order to atomize the liquid fuel for quick combustion there is positioned within the pan 34 a rotatable atomizer disc 40. It is removably secured to the top of a drive shaft 42 driven by a constant speed electric motor 44 of well known design. The rotor of the motor is rotatably carried in a housing 46 suspended below the heater casing 14 by rods, spacers and screws 48 of customary design. The lower end of the housing 46 provides an inlet 49 for liquid fuel and a well 50. The drive shaft 42 extends down through a protective sleeve 52 into such well and its lower end is mounted in a ball bearing 54. A bottom plate 56 holds such bearing in place and closes the lower end of the well 50. The drive shaft 42 as shown in FIGS. 2 and 3 has a central bore 58 forming an oil conduit leading from the well 50 to the top of the disc 40. At the lower end of shaft 42 and within the well 50 is a rotary oil pump impeller 60 provided with an upwardly facing slot 62. As oil enters such slot from the inlet 48 it is impelled outwardly and forced down through the bearing 54 and up through the bore 58. The liquid fuel is fed in metered quantities to the impeller 60 by a liquid level float-type control 64 of standard design at about /2 gallon per hour. The impeller operates at about 3000 r.p.m. and is capable of delivering more oil than is metered to it. Thus such fuel pump acts in a starved condition and its purpose is to lift the fuel to the upper surface of the disc 40 where it forms a film which by reason of the centrifugal force created by rotating the disc at 3000 rpm. is thrown off the periphery of the disc in small enough drops to be characterized as atomized. Combustion supporting air enters through inlets in the wall of the pot to make a combustible mixture which will ignite as soon as the spark igniter is energized.

The cylindrical wall of pct 20 is provided with angularly and vertically spaced inlets. The two lower rows of inlets 70 are primarly inlets. The next two higher rows of inlets 72 are secondary inlets. The last three rows of inlets 74 are tertiary inlets. The function of these inlets is to admit combustion supporting gases in the manner hereinafter set forth.

Fresh air for supporting combustion is drawn into the intake and feed chamber 28 through a restricting opening 76 and a central opening 78 in a cowling 80. The cowling opening 78 surrounds a hollow deflector 82 with an upper radial flange 84 and forms therewith a path directing incoming air into the central opening of a fan 86 for moving the combustion supporting air peripherally outward into the feed chamber 28.

The products of combustion which are generated in the pot 20 and an upper combustion chamber 21 formed by the burner casing 18, after the burner has started operation, are drawn from the combustion chamber 21 down through the passage 24 to an opening '88 in the bottom of the pot 20 which surrounds the drive shaft 42. The products of combustion then are moved upwardly through the center of the director 82 to the central opening of a fan 90 for moving the products of combustion outward into the feed chamber 28.

The fans 86 and 90 (see FIG. 6) are constructed as one unit supported by a closed upper wall 92 mounted on a hub 94 carried by the shaft 42. Each fan has 6 straight radially positioned blades 96 mounted'in vertical alignment but separated by a partition 98 with a central opening 99. The bottom of the fan 86 has a lower wall 100 with an inlet opening 101. The combustion supporting air enters the lower fan 86 through the central opening 101 and the products of combustion enter the upper fan 90 through the central opening 99. The mass of combustion supporting air moved by fan 86 is controlled by the size of a combustion air inlet 78 and the fan operating at 3000 rpm. has a greater capacity and is working in a starved condition and imparts the required velocity to the air. The mass of products of combustion moved by the upper fan 90 is controlled by the size of the opening 88 and such fan also operates in a starved condition and imparts the required velocity to such products of combustion.

For more easy manufacture the drive shaft 42 enters the bottom of the heater casing 14 through an opening 102 large enough to avoid problems of alignment and close tolerances. There may be a collar 104 surrounding such opening to act as a bafile to limit the amount of incoming fresh air. There will be a small amount of fresh air drawn into the stream of the products of combustion by the upper fan 90. The amount, however, is so slight as to be inconsequential in the proportioning of the air and such products. This burner is designed to operate on approximately 18 cu. ft. of combustion supporting air per pound of fuel. The restrictive openings 76 and 88 are relatively sized with respect to each other so that the mass of the products of combustion entering the feed chamber 28 is about the same as the mass of fresh air entering such chamber. However, the burner will work satisfactorily if the mass of such products of combustion is in the range of 25 to 75% of the mass of the fresh air.

An important feature of this invention is the manner in which the products of combustion are brought into the feed chamber 28 by the upper fan 90. This fan is above the air fan 86 and is placed very close to the bottom of the pot 20. As the products of combustion are combined with the air upon leaving the periphery of the fan 90 and are moved along the feed chamber 28 up to the primary inlets 70, there will be a higher concentration of the products of combustion in the combined mass in that portion close to the wall of the pot, than in that portion remote from the pot. Thus as the combined mass is moved through the primary inlets 70, it will have a high concentration of the products of combustion. However, this bleeding off the high concentration of the products of combustion at the primary inlets lessens such concentration and the combined mass as it enters the secondary inlets 72 will have a lower con-centration of the products of combustion. By the time the combined mass enters the tertiary inlets 74 the concentration of the products of combustion will be proportionately lower. This diminishing of the concentration of products of combustion in the combined mass which enters the pot from primary to tertiary inlets is offset by the creation by combustion within the pot of products of combustion. This creation Within the pot is also greater at the higher levels than at the lower levels. The effect is to maintain a fairly constant concentration of the products of combustion throughout the entire pot. It is believed that this uniform concentration contributes to the exceptionally clean burning of the fuel, the high efficiency, and the smokeless characteristics of this burner.

There may be mounted within the pot 20 a flame spreader 106 of customary design. In this particular embodiment this flame spreader helps to create a more even flame condition. However, it may not be needed if other components of a burner of this type are altered in relative size.

Although but one embodiment of the present invention has been illustrated and described, it will be apparent to those skilled in the art that various changes and modifications may be made therein without departing from the spirit of the invention or from the scope of the appended claim.

-What is claimed is:

A pot-type burner having:

a pot having a side wall provided with inlets, said inlets being vertically spaced in rows providing a lower primary row and at least one other row above said primary row, said pot forming part of a combustion chamber;

means for introducing a metered amount of atomized liquid fuel to said pot;

an igniter associated with said pot for starting combustion of said fuel;

an intake and feed chamber for conducting combustion supporting air to said inlets, said chamber having an air intake opening;

a combination chamber above said pot;

conducting means connecting said combustion chamber and said intake and feed chamber, and having a restriction therein; and

fan means consisting of a first section adjacent said pot for moving products of combustion and a second section remote from said pot for moving combustion supporting air, said first section being nearest said primary row whereby the combined mass of said products of combustion and said combustion supporting air passing into said primary inlets will have a higher concentration of products of combustion than such combined mass entering said other row of inlets.

References Cited by the Examiner UNITED STATES PATENTS 2,048,321 7/1936 Carruthers et al 158-1 2,099,092 11/1937 Arnold 158-4 2,200,278 5/1940 Johnston 158-1 2,284,157 5/ 1942 Leonard 1581 2,597,033 5/1952 Ray 1584 FREDERICK L. MATTESON, JR., Primary Examiner.

MEYER PERLIN, JAMES W. WESTHAVER,

Examiners.

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