US2732892A

US2732892A - Oil burner

Info

Publication number: US2732892A
Authority: US
Publication date: 1956-01-31
Anticipated expiration: 1973-01-31

Description

Jan. 31, 1956 H. w. KELLY 2,732,892

OIL BURNER Filed Oct. 20, 1952 6 Sheets-Sheet 1 IN VEN TOR. HENRY W. KELLY TTORNEYS Jan. 31, 1956 H. W. KELLY OIL BURNER Filed Oct. 20. 1952 6 Sheets-Sheet 2 IN VEN TOR. HENRY W. KELLY ATTORNEYS H. W. KELLY Jan. 31. 1956 OIL BURNER 6 Sheets-Sheet 3 Filed Oct. 20, 1952 FIG. 3

INVENTOR. HENRY W. KELLY RNEYS Jan. 31, 1956 Filed 001.. 20. 1952 H. w. KELLY 2,732,892

OIL BURNER 6 Sheets-Sheet 4 lld o o o o o L) g 41 0 o o o 9 o o o 0 Fl G 5 INVENTOR.

HENRY w. KELLY BY m, n

ATTORNEYS H. W. KELLY Jan. 31, 1956 OIL BURNER 6 Sheets-Sheet 5 Filed Oct. 20, 1952 FIG. 6

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ATTORNEYS Jan. 31. 1956 H. w. KELLY 2,732,892

OIL BURNER Filed Oct. 20, 1952 6 Sheets-Sheet 6 FIG. 8

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HENRY W. KELLY ATTORNEYS United States Patent 01L BURNER Henry W. Kelly, Columbus, Ohio Application October 20, 1952, Serial No. 315,769

9 Claims. (Cl. 158-91) My invention relates to an oil burner. It has to do, more particularly, with the pot type of oil burner.

This application is a continuation-in-part of my copending application Ser. No. 237,980, filed July 21, 1951.

One of the great difficulties encountered in the use of present-day pot type burners is the formation of carbon deposits, because of improper combustion, which requires frequent removal and cleaning. This formation of carbon deposits in the burner is due to improper supply of air for combustion thereto, insuflicient purging of carbon-dioxide therefrom, and insuflicient vaporization of the oil supplied thereto. Furthermore, these prior art pot type burners require a very good draft to function with any degree of success at all because of the resistance to air flow therethrough due to friction and to back-pressure resulting from the construction of such burners. Also, they are so constructed that to obtain any degree of vaporization of the oil at all, the bottom of the pot must be spaced a considerable distance above the bottom of the furnace to prevent chilling of the bottom and consequent interference with vaporization. This is undesirable, especially in floor-furnace installations where space is limited and it is desirable to keep the depth of the furnace to a minimum.

One of the objects of my invention is to provide a pot type oil burner which is of such design and construction as to require a minimum of draft for it to function effectively without smoking and forming carbon deposits.

Another object of my invention is to provide a pot type oil burner which is so designed and constructed as to reduce to a minimum resistance to the flow of air for combustion thereinto and the purging of carbon-dioxide therefrom.

A further object of my invention is to provide a pot type oil burner which is not only designed and constructed to facilitate the flow of air thereinto but is actually provided with an air supplying arrangement which will positively supply air thereto where needed for proper vaporization of the oil and will purge the carbon-dioxide effectively therefrom.

An additional object of my invention is to provide a pot type oil burner of the design and construction indicated above which not only provides for the supply of air in a proper manner to purge the carbon-dioxide therefrom and for proper combustion but also is so designed and constructed that the burner, and especially the bottom thereof, is insulated from ambient cold air which would tend to interfere with vaporization.

Still another object of my invention is to provide a pot type oil burner which is of such a design and construction that it can be placed with its bottom substantially at the same level as the bottom of the furnace in which it is used, even if it is used in a floor furnace which has its bottom almost in contact with the bottom of a pit where the ambient air will be cold.

According to my invention, I provide a burner which comprises a cylindrical pot with the usual means for sup- Patented Jan. 31, 1956 plying oil in the lower portion thereof over the imperforate bottom thereof. The upstanding sidewall of the burner is provided with a series of air supply openings extending therethrough. Spaced slightly above the bottom is a pilot ring which is angled upwardly and inwardly towards the axis of the pot. Some of the air openings are below this ring and supply primary air for combustion while other air openings are above the ring and supply secondary air. Tertiary air openings are adjacent the upper edge of the upstanding wall and are arranged in a horizontal row or rows of closely spaced openings, these openings being just below the large central draft opening at the top of the burner.

Centrally disposed within the pot burner and upstanding therefrom is an air tube for positively supplying air to the burner at the upper side thereof. This tube extends upwardly from an opening in the bottom of the pot and terminates just below the level of the row or rows of tertiary air openings where it opens upwardly. This air supply tube extends centrally through the pilot ring and its upper end is centrally of but below the main draft opening. Air supplied to the lower end of the tube is delivered from the upwardly opening upper end thereof and the delivered stream serves to draw the gases and flame upwardly from the bottom of the pot, through the central opening in the pilot ring and form a cone of gases and flame. The stream of air from the upper end of the tube also draws or induces air into the burner through all the openings in the upstanding wall and especially through the tertiary air openings adjacent its upper end. The result is that an adequate supply of air for combus tion is provided especially at the upper portion of the cone of flame. The air tube is provided with a pair of helical baflles which start at opposed diametrical points and extend vertically around the interior of the tube and with which the air must contact as it passes upwardly through the tube so that it will be effectively preheated before discharge and which cause the preheated air to be discharged from the tube with a twisting or swirling motion which will result in a better mixture of air and oil vapor. Furthermore, at the upper end of the tube it is provided with an annular baflle which is arranged between the upper ends of the two helixes and serves to cause the air to travel in contact with the helixes as it passes upwardly through the tube and prevents it from sweeping up freely through the center of the tube.

The preheated air discharged from the upper end of the tube is a positive force which purges carbon dioxide from the upper portion of the burner and relieves backpressure above the flame and which also induces other air into the burner through the openings in the upstanding wall thereof as explained above. The carbon dioxide is heavier than air and, therefore, must be forced positively from the burner which is accomplished with the central air tube arranged according to my invention. The tube is heated by surrounding gases and flame and the air passing therethrough winds around the helical baffle with the result that the air is preheated before being discharged upwardly into the burner from the upper end thereof. The air is discharged where it is needed most, that is, at the center of the burning gases. The air passing through the tube also prevents overheating thereof by the surrounding flame and gases.

The air is supplied to the central tube by means of a passageway in an air duct member which extends below the bottom of the burner and which is supplied with air either by natural draft or forced draft. This duct not only serves to supply air to the central tube but also provides a means for insulating the bottom of the burner from the ambient air which might be cold and would otherwise interfere with the vaporizing of the oil at the bottom of the burner. The result is that the bottom of the burner can be disposed practically in contact with the ground, for example, when it is installed in a floor furnace. The duct can also have additional passageways for supplying air to the side of the burner remote from the source of air.

The preferred embodiment of my invention is illustrated in the accompanying drawings wherein similar characters of reference designate corresponding parts and wherein:

Figure 1 is a vertical sectional view through a floor furnace in which my burner has been incorporated, this furnace being provided with a forced draft arrangement.

Figure 2 is a vertical sectional view similar to Figure 1 but showing my burner in a slightly different type of furnace, the furnace shown being provided with a natural draft arrangement.

Figure 3 is an enlarged vertical sectional view taken through the burner and showing how it functions.

Figure 4 is a plan view of the burner shown in Figure 3.

Figure 5 is an isometric view of the burner.

Figure 6 is a plan view similar to Figure 4 but showing a natural draft arrangement for the burner.

Figure 7 is an isometric view of the burner of Figure 6 taken from the side where the draft openings are provided.

Figure 8 is a plan view of the upper end of the air tube showing the annular baffie at the upper end of the air tube.

Figure 9 is an enlarged vertical sectional view taken through the upper end of the air tube substantially along line 9-9 of Figure 8.

With reference to the drawings, in Figure l, I have illustrated a floor furnace in which my burner unit 10 may be used. However, it is to be understood that my burner may be used with other types of furnaces or other heating units.

The furnace illustrated comprises a combustion chamber 11 and a heat radiator unit 12 which are in communication through a passage 13. My burner 10 is disposed in the lower end of the combustion chamber 11 which is of square cross-section. Due to its special construction, the bottom of my burner may be located at the bottom 14 of the combustion chamber 11 even though the furnace is in a pit almost in contact with the ground.

My burner 10 comprises a body 15, preferably of sheet metal, which is in the form of a cylindrical pot having the substantially flat bottom 16 and the upstanding circular wall 17. The upper edge of the upstanding wall 17 is provided with a peripheral flange 18 which is bolted to a square collar 19 by means of bolts 20. Gaskets 21 are clamped between the flange 18 and collar 19. The collar 19 has :1 depending flange 22 on its outer edge which may be welded or otherwise secured to the walls 11a of the combustion chamber with which it contacts. The collar 19 is further provided with an upstanding inner flange 23 which serves to provide the central large draft opening 24 at the upper side of the burner. Thus, the burner is suspended within the lower portion of the combustion chamber 11.

The bottom 16 of the burner is imperforate but the upstanding side wall 17 is provided with a series of air supply openings extending therethrough arranged as described below. Spaced slightly above the bottom is the pilot ring 25 which is angled upwardly and inwardly towards the axis of the body 15. This ring is supported by the inwardly extending pins 26. Additional pins or clips 27 are supported by the wall 17 and extend inwardly and downwardly into contact with the ring 25 to prevent it from Warping upwardly. The ring 25 provides a central draft opening 24a which is somewhat smaller than the main draft opening 24.

Some of the air openings 28 are below the pilot ring 25 and supply primary air for combustion. These openings may be arranged in a single row or in other desired manner. Above the pilot ring 25, several rows of openings 29 are provided for secondary air. Adjacent the upper edge of the upstanding walls 17, a plurality of closely spaced tertiary air openings 30 are provided and may be arranged in a single row or multiple rows.

I provide an upstanding air tube 31 for positively supplying air to the burner at the upper end and axis thereof. This tube is centrally disposed and extends upwardly from a central opening 32 in the bottom 16 of the body of the burner. The tube extends upwardly through the opening 24a in the pilot ring and beyond to a point just below the level of the lowermost row of openings where it opens upwardly. Thus, the upper end of the tube is disposed centrally of the main draft opening 24 and below such opening. Within the air tube 31 and extending the full height thereof, I provide a pair of helical bafiles 33. These baflles start at diametrically opposed points at the lower end of the tube and end at diametrically opposed points at the upper end in substantially the same plane as the lower points.

To prevent the air entering the lower end of the tube, from merely sweeping up through the center of the air tube 31 without traveling in the channel provided by the helixes 33 in contact with the wall of the tube, I provide an annular baffle 34 secured to and disposed between the upper ends of the helixes. The baflie member is shown in plan in Figure 8 and in section in Figure 9 in relationship to the upper end of the tube 31. It is of disclike form except that it has a small central air discharge aperture 35. It is of such diameter that it merely fills the space between the opposed helixes, which are of substantial width, with the result that a substantial annular air discharge space 36 is provided between its outer edge and the inner wall of the tube 31. It will be noted from Figure 9 that the upper edge of the tube 31 is chamfered outwardly.

The size of the tube 31 relative to the size of the burner is important. I have found that the cross-sectional areas of these members, that is, the burner and the tube, should be in the ratio of 10 to 1 /2. If the body 15 of the burner has an internal diameter of 10", the tube 31 will have an internal diameter of 1 /2. In a tube having a diameter of 1 /2", I have found it desirable to have the helixes in width. The baflle 34 will have a diameter of so that it will fill the space between the helixes 33 and will extend over the upper ends of the helixes slightly and can rest thereon, being welded thereto.

Air is supplied to the lower end of the tube 31 by a duct member 40 which is below the bottom 16 of the burner and which extends beneath a greater portion of the bottom. This duct member 40, as shown in Figures 4 and 5, is formed of an inverted channel member 41 which has a pair of angle members 42 extending longitudinally thereof so that a central passageway is provided and the side passageways 44 and 45 are provided. The flanges 46 at the edges of the channel rest upon and may be welded or otherwise secured to the bottom 14 of the combustion chamber 11. As previously stated, the combustion chamber 11 is of square form and the duct member 40 extends from one of the walls 11a at one side, beneath the bottom 14 of the burner, to a point spaced slightly from the opposite side of the burner where a small plenum chamber 47 is formed, as shown best in Figure 3. The central passageway 43 in the duct member 40 is provided with an opening 48 which communicates with the lower end of the air tube 31. Thus, the duct member 40 will supply air to the central tube 31.

The duct member 40 can either receive its air from a forced draft source or a natural draft source. Figures 1, 3, and 4 show a forced draft source in the form of a fan or blower 50. This fan or blower is mounted on the wall 11a with which the end of the duct 40 contacts. The fan supplies air through an opening 51 in the wall 11a. This air, as shown best in Figure 3, is forced around the burner and eventually reaches the plenum chamber 47 and then enters the central passageway 43.

small openings into the burner.

It will be noted from Figure 3 that the opposite end of the passageway 43 is closed by the wall 11a with which the duct member 40 contacts. As indicated by the arrows, some of the air will be forced beyond the tube inlet opening 48 but since the opposite end of the passageway 43 is closed, the air will eventually back up into and through the opening 48. Some of this air is also forced through the various openings in the upstanding side wall 17 of the burner, as indicated in Figure 3.

A natural draft source of air for the tube 31 is shown in Figures 2, 6, and 7. The furnace shown in Figure 2 is slightly different from that of Figure 1 being provided with a smaller radiator 120. In this furnace, the burner structure and the duct structure are exactly the same as before. However, instead of providing a fan 50 in association with the opening 51, the opening merely communicates with the atmosphere, and an additional opening or slot 51a (Figures 2 and 7) is provided in wall 11a for draft. Also, in the lower end of the wall 11a a slot 1111 (Figure 7) is provided through which air can enter into the duct 40. In this instance, the air will flow through the slot 11b and enter into the

passageways

43, 44, and 45. The air entering the passageway 43 will pass upwardly through the opening 48 into the tube 31. In this instance, the

passageways

44 and 45 will have the additional function of supplying air from the draft source to the burner at that side of the combustion chamber opposite the slot 11b.

Whether the burner is used under forced draft conditions or natural draft conditions, its functioning is practically identical. In either instance, air is supplied to the lower end of the central air tube 31. This positive supply of air is delivered from the upwardly opening upper end of the tube 31 and the delivered stream of air serves to draw the gases and flame upwardly from the bottom of the pot 15, through the central opening 24a in the pilot ring 25 and form a cone of gases and flame, as indicated inFigure 3. The stream of air from the upwardly opening upper end of the tube 31 also draws or induces or inspirates air into the burner pot through all the openings in the upstanding wall 17 and especially through the uppermost openings 30 adjacent its upper end. Thus, a positive force is added to the draft force for pulling the air through the openings in the wall of the pot and, therefore, less draft is required. The result is that an adequate supply of air is provided for combustion especially at the central portion of the cone of flame, resulting in clean burning. The helical bafiles 33 cause the air to discharge from the tube 31 with a twisting or swirling motion which will result in a better mixture of air and oil vapor adjacent the upper end of the tube, that is, in the central portion of the cone of flame. The air will be caused to take a longer tortuous path by the helixes 33 during its upward travel through the tube 31, and will be kept in contact with the hot wall of the tube longer so that it will be more effectively preheated. The annular baflle 34 at the upper end of the tube will prevent sweeping of the air upwardly through the core of the tube 31 without traveling in contact with the helixes 33 and the wall of the tube. This will ensure more effective preheating of the air and ensure that it will be discharged with a swirling motion so that it will more effectively create turbulence of the gases in the cone-shaped body. The small aperture 35 at the center of the bafiie 34 still will supply sufficient air at the extreme center of the burning core of gases to prevent stagnation thereof so as to ensure proper combustion thereof. Even though the battle 34 is provided, the relatively large annular discharge space 36, which is the width of the baffles 33, provides a large upwardly opening space through which the air can be discharged with less frictional resistance than if the same area was provided by a plurality of Inspiration of the air, by means of the positive discharge of air from the upper end of the tube 31, will ensure that sufficient air will be supplied to the outer portions of the cone of gases ris ing from the burner.

The air discharged from the upper end of the tube 31 also serves as a positive force which purges carbon dioxide from the upper portion of the burner, especially in the initial stages of operation of the burner. This serves to relieve back pressure above the flame. The carbon dioxide, being heavier than air, must be forced positively from the burner and this is accomplished with my arrangement. Although the tube 31 is surrounded with hot gases and flame, and especially the upper portion thereof, it will not overheat to such a degree as to cause disintegration because air continuously passes upwardly therethrough. The draft opening 24 at the upper end of the burner 10, being substantially larger than the opening 24a in the pilot ring 25, prevents the necessary expansion of the body of the gases as it moves upwardly out of the burner.

The duct 40 not only serves to supply air to the central tube 31 but the

passageways

43, 44, and 45 therein serve as an insulating means for the bottom 14 of the burner 10. The bottom of the burner is thus insulated from the air below the furnace which might be very cool, especially if the furnace is so located in a pit so that the bottom 14 of the combustion chamber almost contacts with the ground. Thus, my burner arrangement makes it possible to have less ground clearance for the furnace.

It will be apparent from the above description that I have provided a pot type burner having many advantages. A number of these advantages have been discussed and others will be apparent.

Having thus described my invention what I claim is:

1. A burner for burning oil or similar fuel comprising a pot type body, said body being provided with an imperforate bottom and with an upstanding side wall to provide a large centrally disposed draft opening at the upper end of the body, said side wall being provided with air inlet openings adjacent its upper edge around the periphery thereof, a pilot flange located within the body on the side wall at a level spaced substantially above the bottom and spaced substantially from the upper end of the body and extending inwardly from the side wall but having its inner edge terminating substantially from the center of the body to provide a centrally located large draft opening in axial alignment with the large draft opening at the upper end of the body, and an upwardly opening air inlet tube having an opening of substantially cross-section extending therethrough located centrally of the bottom of the body and extending upwardly from an air inlet opening in the bottom to a point just below the level of said air inlet openings at the upper edge of said body, said tube being centrally disposed within the draft opening in the pilot ring and being spaced substantially from the inner edge of said ring, said side wall of the body also being provided with pilot air openings below the level of said pilot ring and around the periphery of said side wall, said air tube serving to positively discharge preheated air therefrom at its upper end and to inspirate air from said inlet openings at the upper edge of said side wall and from said pilot openings below the pilot ring to provide for more perfect combustion, and an annular bafile disposed at the center of the upper end of the tube to prevent sweeping of the air upwardly through the core of the tube and to force it to travel in contact with the wall thereof for preheating.

2. A burner according to claim 1 wherein said air inlet tube is provided with a pair of helical bafiies which cause the air entering the tube to travel a longer path through the tube so that it will be effectively preheated and which create turbulence of the air as it is discharged from the upper end of the tube, said annular bafile being disposed between the upper ends of the helical baffles so as to provide an annular discharge outlet of the width of the helical baflles.

3. A burner according to claim 2 wherein the annular baffie has a small opening at its center.

4. A burner according to claim 3 wherein the pilot ring is inclined upwardly and inwardly towards the axis of said body.

5. A burner according to claim 4 wherein the draft opening at the upper end of the body is substantially larger than the draft opening in said pilot ring.

6. A burner according to claim 5 wherein the side wall of the body is provided with additional air inlet openings around its periphery between the pilot ring and the air inlet openings at the upper edge thereof.

7. A burner according to claim 6 wherein means is provided for supplying air to said air inlet tube, said means comprising a duct member extending under the bottom of the pot body and communicating with said inlet opening in the bottom of said body.

8. A burner according to claim 7 mounted in a furnace, a combustion chamber in said furnace, said duct member resting on the bottom of said combustion chamber and insulating the bottom of the body of the burner therefrom.

9. A structure according to claim 8 wherein said duct member has a central air passageway which communicates with said tube and has air passages at opposite sides of the central passageway.

References Cited in the file of this patent FOREIGN PATENTS France Feb. 2, 1948