US3303868A

US3303868A - Flame-holding and transition control means for pot-type oil burner

Info

Publication number: US3303868A
Application number: US470812A
Authority: US
Inventors: Gerald L Hershey; Frank A Lowe
Original assignee: Coleman Co Inc
Current assignee: Coleman Co Inc
Priority date: 1965-07-09
Filing date: 1965-07-09
Publication date: 1967-02-14
Anticipated expiration: 1984-02-14

Description

Feb 1957 I G. L. HERSHEY ETAL 3,303,863

FLAME-HOLDING AND TRANSITION CONTROL MEANS FOR POT-TYPE OIL BURNER Filed July 9, 1965 3 Sheets-Sheet 1 INVENTORS: GERALD L, HERSHEY FRANK A. LOWE ATT'YS Feb 1967 G L HERSHEY ETAL 3, 03,

FLAME'HOLDING AND TRANSITION CONTROL MEANS FOR POT'TYPE OIL BURNER Filed July 9, 1965 3 Sheets-Sheet 2 HIGH FIRE OOOOOOOOOOOOOOOOO O 00000 5O INVENTORS.

GERALD L. HERSHEY FRANK A. LOWE BY: flaw m fh gkdfmw, l e/m uad AT T Y S Feb. 14, 1967 G. 1.. HERSHEY ETAL 3,303,868

FLAME-HOLDING AND TRANSITION CONTROL MEANS FOR POT-TYPE OIL BURNER Filed July 9, 1965 3 Sheets-Sheet :3

INVEN'IORS: GERALD L. HERSHEY FRANK A. LOWE ATT'YS BY: fiuugm Giul a, a

United States Patent FLAME-HOLDING AND TRANSITION 0NTRGL MEANS FOR POT-TYPE 01L BURNER Geraid L. Hershey and Frank A. Lowe, Wichita, Kans., assignors to The Coleman Company, Inc., Wichita,

Kans., a corporation of Kansas Filed July 9, 1965, Ser. No. 470,812 19 Claims. (Cl. 158-91) This invention relates to flame-holding and transition control means for pot-type oil burners. This invention is particularly adapted for use with vaporizing burner pots employing a gravity oil feed and a regulated forced combustion air supply. While the improved pot-type burners of this invention are particularly designed for use in furnaces installed in mobile homes, the burners are also well adapted for other furnace or space-heating uses.

Pot-type oil burners have been known and used for many years, and many forms and modifications thereof have been proposed. A recently proposed design is described in Mueller Patent 3,147,796. While the present invention was developed entirely independently of the design of the Mueller patent, many of the features of the present invention can be regarded as constituting improvements thereover.

Pilot housings, such as the one described in the cited Mueller patent, have been proposed in various forms for use with pot-type burners, as illustrated, for example, by Miller et al. Patent 2,448,148, Huston et al. Patent 2,460,- 013, and Jenson et al. Patent 2,699,820. While the enclosure of the fuel inlet with a pilot housing is desirable for holding and maintaining the flame, particularly at pilot fire rates, the housing may tend to cause a smoky or sooty flame during the transition from pilot fire to intermediate or high fire rates. The flame may also tend to pulse or bounce during transition periods. A recirculated type flame, where combustion products are mixed with the oil vapors and air while avoiding a large excess of air, is particularly subject to smoking and/or pulsation during transition periods. Pot-type burners have operated reasonably satisfactorily at either pilot, intermediate, or high fire rates, but no pot-type burner has heretofore been provided which is cap-able of achieving stable, sootless combustion at all fire rates from pilot to high fire, or which is capable of producing a sootless, nonsmoky fire under pilot fire rates or during the transition from pilot fire to intermediate or high fire rates.

Pilot housings fomed of sheet metal, as shown, for example, in Huston Patent 2,460,013 and Jenson et al. Patent 2,699,820, may not be satisfactory because of the unequal heating and cooling of the thin metal walls of the housing, particularly the top wall where the pilot flame heat is concentrated. A heavy cast metal construction can be used, but this is more expensive to manufacture. Such a cast metal construction is illustrated by Mueller Patent 3,147,796.

Still another problem is that of the tendency of the flame to flutter or pulsate under pilot fire conditions within the pilot housing. Heretofore, the exact nature of this problem has not been recognized or understood.

Another problem encountered with pot-type burners is that of flooding. Where the oil is fed by gravity to the burner pot, it is common to employ a constant level valve to regulate the supply of fuel. Where the bottom of the burner has a dished configuration, sloping toward the center, under some conditions of operation a substantial volume of oil can accumulate. With this flooded pot" condition, it may take as long as thirty minutes for the oil in the burner, plus that coming in from the constant level valve, to be consumed at a point Where the burner is functioning normally; During this flooded pot burn-off, excessive smoke, soot, noise and heat are produced in the unit.

It is a general object of the present invention to provide a pot-type burner of improved construction which substantially overcomes the problems and difliculties described above. More specifically, it is an object to provide an improved flame-holding and transition control means for a pot-type burner which is capable of achieving stable, substantially sootless, flame at all fire rates from pilot to high fire, and which also provides for smooth transition between fire rates without bounce or flame pulsation and without undue sooting or smoking. A specific object is to provide a pilot housing which achieves substantially sootless combustion at pilot fire rates. Another specific object is to provide means associated with the pilot housing for reducing flame fluctuation or pulsation at pilot fire rates. Still another specific object is to provide a burner pot construction which reduces or minimizes the problem of pot flooding and the prolonged period of burn-off after flooding. Finally, it is an object to provide a burner which accomplishes the results just described while operating quietly under varying draft conditions that may be imposed upon it. Further objects and advantages will be indicated in the following detailed specification, such as the design feature which permits the pilot housing to be formed of sheet metal.

This invention is shown in an illustrative embodiment in the accompanying drawings, in which FIGURE 1 is an elevational perspective view, with some portions thereof being broken away and shown in section, of a pot-type oil burner embodying the features of the present invention;

FIG. 2 is a top plan view of the pot burner of FIG. 1, with part of the upper flame ring being broken away to more clearly show the pilot housing;

FIG. 3 is a side elevational view, taken in section, of the same burner pot;

FIG. 4 is a fragmentary sectional view of the pilot housing taken on line 44 of FIG. 3; and

FIG. 5 is a fragmentary sectional view of the pilot housing taken on line 55 of FIG. 3.

Looking first at FIG. 1, there is shown a burner pot designated generally by the number 10, which has an open top, a closed bottom 11, and a circumferential side wall 12. Side wall 12 provides air inlet perforations at levels above the lower portion of the pot, such as the row of primary

air inlet perforations

13, 14, and 15, and the row of secondary air inlet perforations 16.

In the illustration given, the perforations within each of the

rows

13, 14, 15, and 16 are evenly spaced, and the perforations are. horizontally aligned, except for the perforations in row 16, which are tipped upwardly, as shown more clearly in FIG. 3. The perforations 13 introduce air into the lower portion of the pot beneath control ring 17, while perforations, 14, 15 and 16 introduce air into the upper portion of the pot above control ring 17. The perforations 16 introduce air in an upward direction adjacent the inwardly-extending portion of the upper flame ring 18, which provides an outer flange portion 1811 that is received on the outwardly-extending flange 12a of the pot side wall, and is attached thereto by spot welding. In the illustration given, and preferably, the upper flame ring 18 provides an inwardly extending portion 18b which slopes inwardly and upwardly. If desired, the outer portion of flange 18a may be provided with mounting holes 19, as shown in FIGS. 1 and 2.

In accordance with the present invention, there is provided a pilot fire zone 20, including a mixing zone in the outer portion thereof, which is located adjacent a side portion of bottom 11, and extends toward the center of the bottom. Preferably, the outer end of zone 20 is closed by part of the lower portion of side wall 12, which includes the upwardly-extending portion of bottom 11. A housing designated generally as 21 is mounted within the lower portion of the pot, and provides wall means enclosing the top and sides of the pilot fire zone 20. In the illustration given, housing 21 has vertically-extending side walls 21a and 21b, and a flat top wall 21c. Housing 21 has an open inner end 22 of restricted cross section as compared with the cross section of the housing. Preferably, the side walls 21a and 21b converge in an inward direction, and top wall 21c slopes downwardly and inwardly, thereby progressively decreasing the cross ection of housing 21 from the outer to the inner portion thereof.

It is not necessary for housing 21 to be sealed to the sides or bottom of the burner. In the illustration given, housing 21 is mounted by means of tabs 23 which extend upwardly from the outer end of top wall 210 and are connected to the side wall 12 by any suitable means, such as rivets for permanent attachment, or bolts where it is desired to make housing 21 readily removable. The sides 21a and 21b of the housing may extend downwardly into a recess 24 formed in the outer portion of the bottom.

It has been found that the operation of housing 21 can be improved by incorporating therein verticallyextending baffle means dividing the outer portion of the pilot fire zone into at least two inwardly-extending passages. One of the passages should converge inwardly to an outlet within the housing of restricted cross section, while the other of the passages enlarges inwardly to an outlet within the housing of enlarged cross sec-tion. In the illustration given, two laterally-spaced, verticallyextending baffles or

deflectors

25 and 26 are provided within the outer portion of the pilot fire zone 20. As shown more clearly in FIGS. 4 and 5, the

deflectors

25 and 26, respectively, have attachment flanges 25a and 26a which are rigidly connected to the underside of top wall 210 by spot welding. As shown in FIG. 4, the

baffle walls

25 and 26 incline inwardly and downwardly, so that the passage 27 therebetween converges in crosssection-al area toward the restricted opening 28 at the inner end of passage 27. The side passages 29 and 3t) enlarge toward their respective inner ends 31 and 32. Preferably, the outer ends 33, 34 and 35 (FIG. respectively, of the

passages

29, 28 and 30, as well as their inner ends 31, 28, and 32, are in open communication. In the illustration given, the outer ends of baflles 29 and 3t) terminate at spaced distances from the burner side wall 12, which includes the upwardly-extending portion of bottom 11, to provide the desired open flow communication, and the inner ends of the passages terminate within housing 21, as shown in FIG. 5.

For cooperation with housing 21 and the baffles and 26, there is provided separate oil and air inlet means communicating with the outer portion of the pilot fire mixing zone 20. In the illustration given, the oil inlet means comprises a pipe 36 which has an inner section 36a communicating with an opening 37 in the lower portion of wall 12, or, more specifically, in that portion of side wall 12 provided by the upwardly-extending portion of bottom 11. The section 36a may be in the form of a nipple which is connected to wall 12 by brazing, and which provides a threaded connection with the pipe 36, which may be a pipe elbow for connection to a longer oil supply pipe.

Preferably, the oil inlet opening 37 is located immediately above the adjacent portion of bottom wall 12, and the terminal section 36a of pipe 36 is inclined outwardly and downwardly with respect to the horizontal. The angle of inclination is of importance, and preferably is within the range of from 20 to 50, for example, an inclination of with respect to the horizontal.

In the illustration given, the air inlet means to the pilot fire zone 20 comprises a row of perforations 38 which are located in side wall 12 just below the outer end of housing top wall 21c, as shown in FIGS. 3 and 5. Preferably, the perforations 38 are tipped downwardly so as to tend to direct the incoming air toward the bottom of zone 20. As shown in FIG. 5, some of the perforations are aligned with the

side passages

29 and 30, but most of the perforations are aligned with the central passage 27.

When housing 21 is formed of sheet metal, as preferred, it is desirable to provide a protector strip 39 which is supported adjacent the underside of the housing top wall 210 by means permitting the protector strip to expand and contract independently of the top wall. Strip 39 may be conveniently formed of sheet metal. In the illustration given, the outer end portion of strip 39 is rigidly attached to the top wall 210, such as by spot welding, and the inner end portion of the strip is turned upwardly over the inner end portion of top wall 210 to form a slidable support therefor, as shown more clearly in FIGS. 2 and 3. The inner portion of strip 39 is therefore free to expand laterally and inwardly on being heated without causing distortion of top wall 210, the direction of expansion being indicated by the arrows in FIGS. 2 and 3.

The operation of the pilot fire zone 20 is further improved by providing an oil-holding depression or sump 40 adjacent the oil inlet opening 37. Preferably, sump 49 comprises the lowest portion of bottom 11. It is desirable to mount a flat, non-combustible wick 41 within sump 40. In the illustration given, the wick 41, which may be formed of asbestos fibers, is held in place by a metal strap 42 which is secured to bottom wall 11 by spot welding. Preferably, wick 41 extends up to the oil inlet opening 37 so that the oil as it enters will fall on the wick 41.

The operation of burner 10, particularly during the transition from pilot fire rates to high fire rates, is significantly improved Where the housing 21 extends only part of the way toward the center of the bottom, and a vertically-extending ring, such as the ring 42, encloses a central zone 43 in the lower portion of the pot. One side of the ring 42 has an opening therethrough in direct communication with the open inner end 22 of the housing 21. In the illustration given, the ring 42 is U-shaped, and provides vertically-extending flanges 42a and 4217 which are attached to the forward ends of the housing side walls 21:: and 2111. One preferred means of attachment is by means of rivets, such as the

rivets

44 and 45, that have one end connected respectively to the

flanges

42b and 42a and the other end slidably and pivotally received in the grooves 46 and 47. The sliding hinge connection thereby provided facilitates the insertion of the assembly of the housing 21 and the ring 42, and the conformity of these parts to the contoured shape of bottom 11.

While ring 42 may have imperforate side walls, the operation of the burner is improved where a plurality of openings 48 are provided in the lower portion of the ring 42. The openings 48 provide communication between the bottom of the central zone 43 and the surrounding peripheral zone 49 beneath the control ring or baffle 17. It has been found that a specific construction of the control ring 17 cooperates in a particularly effective manner with the pilot flame ring 43, and this construction will now be described.

As shown more clearly in FIGS. 1 and 3, the control ring 17 is in the form of an annular baffie plate, which has its outer portion supported against the burner side wall 12 by means of support pins 50 and retaining clips 59, which are spaced circumferentially around the outer portion of the ring. In accordance with the present invention, the inner portion of the baflie plate 17 comprising the portion 17a, inclines downwardly and inwardly' to a central opening which is centered over ring 42. Preferably the baffle 17, including the downwardly and inwardly inclined portion 17a, is positioned at a spaced distance above the top of the ring 42. The central opening in the baflle ring 17 is preferably of larger diameter than the diameter of the ring 42, as shown in the drawings.

The flooded volume of the pot may be reduced While at the same time improving the operation of the burner by employing a specially shaped or contoured bottom. More specifically, the bottom 11 may be shaped or formed to provide a depressed oil-holding channel 50 extending around the outside of ring 42 immediately adjacent thereto, as shown more clearly in FIGS. 1 and 3. The central portion of bottom 11 which is enclosed by the ring 42 preferably has a part thereof, such as the part 51, which is raised above the lowest portion of channel 50, and the rest thereof being at a lower level, such as the portion 52 (FIG. 3). Channel 50 and bottom portion 52 are disposed so that they are in liquid flow communication with the oil inlet opening 37. In the illustration given, bottom portion 53 and channel 50 are in flow communication with the inner end of the sump 40 so that as the level of oil increases within the pot, the oil will flow from the sump 40 onto the bottom portion 52 and at the same time into the channel 50.

It'will usually be preferred to form bottom 11 from a separate piece of metal than side wall 12. In the illustration given, bottom 11 is provided with an attachment flange 11a which is connected to the lower end of wall 12 by any suitable means providing a sealed joint, such as seam welding.

Operation The operation of the burner pot will be largely apparent from the foregoing discussion, but it may be briefly summarized as follows:

Fuel oil is supplied by gravity feed and using a constant liquid level valve, through the pipe 36, the terminal inclined section 36a, and the opening 37, being discharged into sump 40 onto the wick 41. At pilot fire rates, the flame will issue from the inner end of housing 21, a typical pilot fire level being indicated in FIG. 3.

The flame under pilot conditions will be stable, substantially smoke-free, and will not be subject to pulsation or fluttering. The flame will be largely confined within the central passage 28 between the baflies 25 and 26. The inner end 28 of passage 27 will serve as a flame-holding means under pilot fire conditions. Combustion products will be recirculated through the

passages

29 and 30 to be mixed with the newly vaporized fuel and air mixture at the entrance 34 to the passage 27. Since the perforations 38 are directed downwardly, air can flow downwardly and forwardly through the bottom portions of the

passages

29 and 30, as indicated by the arrows in FIG. 4, while combustion products are recirculated in the opposite direction through the upper portions of these passages. The recirculation flow is also indicated by arrows in FIG. 5.

The inclination of the terminal pipe section 36a tends to prevent outage of the pilot flame due to excess vaporization of the liquid fuel in the fuel inlet pipe. Because of the angle of the terminal section 36a, oil fills the inlet section to a level, as indicated at 54 in FIG. 3, before it can enter the opening 37. Thus, there is a very limited exposed oil surface within the fuel inlet pipe 36 for vaporization to occur.

By discharging the incoming oil onto wick 41, even at low fuel supply rates, as under pilot fire conditions, the incoming oil is absorbed and spread, stabilizing the vaporization rate, thereby tending to produce a more stable and quiet flame, especially in combination with the inclined inlet pipe section 36a.

Under pilot and higher conditions, the flame issuing from the inner end of passage 27 plays on the underside of the protector strip 39. The strip 39 can expand forwardly without distorting the housing top wall 210, and the strip also serves to protect top wall 21c against the high temperatures produced by direct contact with the tip of the flame under pilot fire conditions, thereby further reducing the tendency of housing 21 to distort even though formed of sheet metal.

As the fire rate is increased by supplying additional fuel, the flame can move to an intermediate position, or on to a high fire position, both positions being illustrated diagrammatically in FIG. 3. Under transition to intermediate or high fire conditions, the annular bafiie 17, also referred to as the control ring, cooperates with the pilot flame ring 43 to produce a quieter, more stable, and less sooty flame than would otherwise be obtained. Apparently, this is due to recirculation of combustion products within the lower portion of the burner, but certainly within the outer zone 49.

The specially shaped and contoured bottom 11 provides a reduced flooded volume which makes the burner safer to operate. It is not necessary to employ a temperaturesensing device in conjunction with the burner for shutting off the flow of oil when the burner is cold. Sufficient control is provided by the liquid level valve. The raised central portion of the burner 51 in combination with the channel 50 provides for a smooth and eflicient operation. Flare-up and die-down effects are avoided, and a smooth transition is obtained by the gradual change in the amount of vaporizing surface.

While in the foregoing specification this invention has been described in relation to a specific preferred embodiment thereof and many details have been set forth for the purpose of illustration, it will be apparent to those skilled in the art that the invention is susceptible to other embodiments and that certain of the details described herein can be varied considerably without departing from the basic principles of the invention.

We claim:

1. In combination:

(a) a burner pot for a pot-type oil burner,

said pot having an open top, a closed bottom, and a circumferential side wall providing air inlet perforations at levels above the lower position thereof;

(b) a pilot fire zone located adjacent a side portion of said bottom,

said pilot fire zone extending toward the center of said bottom and having its outer end enclosed by part of the lower portion of said side Wall;

(c) a housing within the lower portion of said pot providing Wall means enclosing the top and sides of said pilot fire zone,

said housing having an open inner end of restricted cross section as compared with the cross section of said housing;

(d) vertically-extending baflle means within the outer portion of said pilot fire zone beneath said housing and dividing said outer portion into at least two inwardly-extending passages,

one of said passages converging inwardly to an outlet within said housing of restricted cross sec-tion,

the other of said passages enlarging inwardly to an outlet within said housing of enlarged cross section,

the inner and outer end portions of said passages being in open communication; and

(e) separate oil and air inlet means communicating with the outer portion of said pilot fire zone.

2. The combination of claim 1 wherein the wall of said housing enclosing the top of said pilot fire zone is formed of sheet metal, and a protector strip of sheet metal is supported adjacent the underside thereof by means permitting said protector strip to expand and contract independently of said top wall.

3. The combination of claim 2 wherein said protector strip has its outer end portion rigidly attached to said top wall and its inner end portion turned upwardly over the inner end portion of said wall to form a slidable support therefor.

4. The combination of claim 1 wherein said oi-l inlet means comprises a pipe extending to an opening in the lower portion of said side wall immediately above said bottom wall, said pipe terminating in a section adjacent said opening which in inclined downwardly with respect to the horizontal at an angle of from 20 to 50 degrees.

5. The combination of claim 4 wherein an oil-holding depression is provided in said pot bottom adjacent said oil inlet opening.

6. The combination of claim 5 wherein a flat noncombustible wick is provided within said oil-holding depression.

7. The combination of claim 1 wherein said housing extends only part of the way toward the center of said bottom, and a vertically-extending ring encloses a central zone in the lower portion of said pot, one side of said ring having an opening therethrough in direct communication with the open inner end of said housing.

8. The combination of claim 7 in which an annular bafiie plate is supported at the top of the lower portion of said pot at a spaced distance above said housing and ring, said plate having its outer portion adjacent the pot side wall and inclining downwardly and inwardly to an opening therethrough centered over said ring.

9. The combination of claim 8 wherein the lower portion of said ring has openings in the wall thereof communicating with an outer zone of said pot beneath said baffle, the side wall of said pot providing an inlet opening at a level below said bafile for introducing air into said outer zone, the opening in said baflie being of larger diameter than that of said ring.

10. The combination of claim 9 wherein said bottom provides a depressed oil-holding channel extending around the outside of said ring, part of the portion of said bottom enclosed by said bottom being raised above the lowest portion of said channel and the rest being at a lower level, said channel and the said lower part of the ring-enclosed portion of said bottom being in liquid flow communication with said oil inlet means.

'11. In combination:

(a) a burner pot for a pot-type oil burner,

said pot having an open top, a closed bottom, and

a circumferential closed bottom, and a circumferential side wall providing air inlet perforations at levels above the lower position thereof;

(b) a pilot fire zone located adjacent a side portion of said bottom,

(d) vertically-extending baflie means within the outer portion of said pilot fire zone beneath said housing and dividing said outer portion into at least two inwardly-extending passages,

one of said passages converging inwardly to an outlet within said housing of restricted cross section, the other of said passages enlarging inwardly to an outlet within said housing of enlarged cross section;

(e) separate oil and air inlet means communicating with the outer portion of said pilot fire zone; and

(f) a vertically-extending ring enclosing a central zone in the lower portion of said pot,

one side of said ring having an opening therethrough in direct communication with the open inner end of said housing.

12. The combination .of claim 11 in which an annular bafile plate is supported at the top of the lower portion of said pot at a spaced distance above said housing and ring, said plate having its outer portion adjacent the pot side wall and inclining downwardly and inwardly to an opening therethrough centered over said ring.

13. In combination:

(a) a burner pot for a pot-type oil burner,

(b) a pilot fire zone located adjacent a side portion of said bottom,

said housing having an open inner end of restricted cross section as compared with the cross section of said housing,

said housing extending only part of the way toward the center of said bottom;

(d) a verticallyextending ring enclosing a central zone in the lower portion of said pot,

one side of said ring having an opening therethrough in direct communication with the open inner. end of said housing;

(e) anannular baffle plate supported at the top of the lower portion of said pot at a spaced distance above said housing ring,

said plate having its outer portion adjacent the pot side wall and inclining downwardly and inwardly to an opening therethrough centered over said pilot ring; and

(f) separate oil and air inlet means communicating with the outer portion of said pilot fire zone.

14. The combination of claim 13 wherein the lower portion of said ring has openings in the wall thereof communicating with an outer zone of said pot beneath said bafile, the side wall of said pot providing an inlet opening at a level below said balfie for introducing air into said outer zone, the opening in said 'bafi'le being of larger diameter than that of said ring.

15. The combination of claim 13 wherein said bottom provides a depressed oil-holding channel extending around the outside of said ring, part of the portion of said bottom enclosed by said bottom being raised above the lowest portion of said channel and the rest being at a lower level, said channel and the said lower part of the ring-enclosed portion of said bottom being in liquid flow communication with said oil inlet means.

16. The combination of claim 13 wherein said combination also includes laterally-spaced, vertically-extending baffle means within the outer portion of said pilot fire zone beneath said housing and dividing said outer portion into three inwardly-extending passages, the center one of said passages converging inwardly to an outlet within said housing of restricted cross section, the outside two of said passages enlarging inwardly to outlets within said housing of enlarged cross section, and the inner and outer end portions of said passages being in open communication.

17. In combination:

(a) a burner pot for a pot-type oil burner,

(b) a pilot fire zone located adjacent a side portion of said bottom,

said housing having an open inner end of restricted cross section as compared with the cross section of said housing, said housing being formed of sheet metal;

(d) a protector strip of sheet metal supported adjacent the underside of the top of said housing by means permitting said protector strip to expand and contract independently of said top wall; and

18. In combination:

(a) a burner pot for a pot-type oil burner,

(b) a pilot fire zone located adjacent a side portion of said bottom,

(d) separate oil and air inlet means communicating with the outer portion of said pilot fire zone,

said oil inlet means comprising a pipe extending to an opening in the lower portion of said side wall immediately above said bottom wall,

said pipe terminating in a section adjacent said opening which is inclined downwardly with respect to the horizontal at an angle of from 20 to 50 degrees;

(e) an oil-holding depression provided in said pot bottom wall adjacent said oil inlet opening; and

(f) a fiat, non-combustible wick provided within said oil-holding depression.

19. In combination:

(a) a burner pot for a pot-type oil burner,

said pot having an open top, a closed bottom, and

a circumferential side wall providing air inlet perforations at levels above the lower position thereof;

(b) a pilot fire zone located adjacent a side portion of said bottom,

said housing extending only part of the way toward the center of said bottom;

(d) a vertically-extending ring enclosing a central zone in the lower portion of said pot,

.one side of said ring having an opening therethrough in direct communication with the open inner end of said housing;

(e) oil inlet means communicating with the outer portion of said pilot fire zone; and

(f) the bottom of said pot providing a depressed oilholding channel extending around the outside of said ring,

part of the portion of said bottom enclosed by said bottom being raised above the lowest portion of said channel :and the rest being at a lower level,

said channel and the said lower part of the ringenclosed portion of said bottom being in liquid flow communication with said oil inlet means.

References Cited by the Examiner UNITED STATES PATENTS 2,162,844 6/1939 Jenson 158-91 2,537,966 1/1951 Cargile et al 158-91 2,574,358 11/1951 John 15891 2,748,847 6/ 1956 Gilmore et al 15891 2,756,811 7/1956 Little 158-91 3,017,924 1/1962 Jenson 158--91 3,147,796 9/1964 Mueller l5891 FREDERICK KETTERER, Primary Examiner.

Claims

1. IN COMBINATION: (A) A BURNER POT FOR A POT-TYPE OIL BURNER, SAID POT HAVING AN OPEN TOP, A CLOSED BOTTOM AND A CIRCUMFERENTIAL SIDE WALL PROVIDING AIR INLET PERFORATIONS AT LEVELS ABOVE THE LOWER POSITION THEREOF; (B) A PILOT FIRE ZONE LOCATED ADJACENT A SIDE PORTION OF SAID BOTTOM, SAID PILOT FIRE ZONE EXTENDING TOWARD THE CENTER OF SAID BOTTOM AND HAVING ITS OUTER END ENCLOSED BY PART OF THE LOWER PORTION OF SAID SIDE WALL; (C) A HOUSING WITHIN THE LOWER PORTION OF SAID POT PROVIDING WALL MEANS ENCLOSING THE TOP AND SIDES OF SAID PILOT FIRE ZONE, SAID HOUSING HAVING AN OPEN INNER END OF RESTRICTED CROSS SECTION AS COMPARED WITH THE CROSS SECTION OF SAID HOUSING; (D) VERTICALLY-EXTENDING BAFFLE MEANS WITHIN THE OUTER PORTION OF SAID PILOT FIRE ZONE BENEATH SAID HOUSING AND DIVIDING SAID OUTER PORTION INTO AT LEAST TWO INWARDLY-EXTENDING PASSAGES, ONE OF SAID PASSAGES CONVERGING INWARDLY TO AN OUTLET WITHIN SAID HOUSING OF RESTRICTED CROSS SECTION, THE OTHER OF SAID PASSAGES ENLARGING INWARDLY TO AN OUTLET WITHIN SAID HOUSING OF ENLARGED CROSS SECTION, THE INNER AND OUTER END PORTIONS OF SAID PASSAGES BEING IN OPEN COMMUNICATION; AND (E) SEPARATE OIL AND AIR INLET MEANS COMMUNICATING WITH THE OUTER PORTION OF SAID PILOT FIRE ZONE.