US2363192A - Combustion apparatus - Google Patents

Description

NOV. 21,- 1944. J: w MlLLER 2,363,192

COMBUSTION APPARATUS Original Filed Dec. 6, 1939 2 Sheets-Sheet 1 FIG. I

I INVENTORIY. JOHN w. MILLER OMf- Q -A- Nov. 21, 1944. J. w. MILLER COMBUSTION APPARATUS Original Filed Dec. 6, 1939 2 Sheets-Sheet 2 FIG. 2

INVENTOR. JOHN w. MILLER ew f. 761.4 4

Patented Nov. 21, 1 944 UNITED :STATES COMBUSTION APPARATUS John W. Miller, Lansing, Mich, assignor to M- tor Wheel Corporation, Lansing, Mich, a corporation of Michigan .Original application December 6, 1939, Serial No. 30 'i,734. Divided and this application June 24, 1942, Serial No. 448.275 1 8 Claims. This invention relates to oil burners of the vaporizing pot type, and more, particularly to i the means for controlling the air admitted thereto.

This application is a division of my co-pending application for Combustion apparatus, Serial No.

307,734, filed December 6, 1939, now Patent No.

2,213,568 dated March 9, 1943.

The principal object of the invention is to provide a simple and effective means for coordinating the quantity of air admitted to the burner with the quantity of fuel supplied to the burner during the combustion period so as to effect most eflicient combustion of the fuel.

Another object of the invention is to provide means associated with the burner for confining the air admitted to the burner to those zones in which vaporization, premixing and combustion of the fuel occur.

A further object is to provide means for compensating for fluctuations in draft on the burner.

These objects are accomplished in part by providing a plurality of closure means spaced from the burner side wall which confine the admission of air to the aforementioned zone or zones and which closures can be opened successively as the fuel supply is increased. Opening and closing of the closure means is effected automatically through thermostatic devices located in heat exchanging relation to the combustion apparatus.

For a more detailed description of the invention reference is had to the accompanying drawings, wherein:

Figure 1 is a cross-sectional view of an oil burn ing heater having a vaporizing pot type burner therein in which the invention is embodied;

Figure 2 is a fragmentary cross-sectional view on an enlarged scale of a portion of the device shown in Figure 1;

Figure 3 is a fragmentary side elevational view of a portion of the apparatus shown in Figure 1; and

Figure 4 is a fragmentary cross-sectional view of a modified form of the invention.

The invention shown in the drawings, and particularly Figures 1 and 2 thereof, is embodied in a radiant type space heater. The heater comprises an outer casing [0 supported on a plurality of legs II. The legs I I consists of a pair of crossed straps with their ends spaced apart sufliciently to admit air to the lower portion of the casing H). The casing consists of an upper combustion chamber portion l2 and a lower air jacket portion l3. A flue outlet ll having an automatic draft regulator I5 pivotally mounted in one side thereof connects the combustion chamber l2 to a chimney iii to provide for the escape of exhaust gases from the interior of the combustion chamber.

Mounted within the air jacket portion l3 oi. the casing III is a vaporizing pot type burner 11. The burner includes an oilpan l8 forming-the bottom wall of the burner and a tubular side wall I9 welded thereto. In the bottom of the oil pan I8 and adjacent one side of the burner is. a depres-- sion to collect the fuel admitted to the burner at low fire whereby to provide for ready ignition of the fuel. I

The side wall I9 of the burner has a plurality of vertically spaced horizontal rows of primary air inlet openings 2| therein to permit the entrance of air to the burner. Near the upper edge of the burner is a single horizontal row of secondary air inlet openings 22. Located immediately below the secondary air inlet openings is a top wall 23 having a large central opening 24 therein. An anti-explosion baflie 25 is positioned directly above the top wall and above the secondary air inlet openings 22. Intermediate the top and bottom rows of primary air inlet openings 2i is a centrally apertured inclined partition 26. The lower edge of the partition 26 is located directly above the depression 20 in theoil pan [8 and above the lowermost row of air inlet openings 2|. The upper end of the partition 26 is positioned below the two uppermost rows of primary air inlet openings 2!.

Mounted on the side wall of the casing III) is a metering device 21. The metering device is connected to a suitable source of fuel (not shown) and is also connected to the burner by means of a pipe 28 for supplying fuel to the burner. The metering device is equipped with a fuel regulating valve (not shown) adapted to be rotated by a shaft 29 extending upwardly therefrom. Rotation of the shaft 29 in one direction opens the valve and increases the rate of supply of fuel to the burner while rotation of the valve in the opposite direction closes the valve and decreases the fuel supply.

Surrounding the burner side wall at points intermediate the upper and lower edges thereof are three annular rings 30 in sealed engagement with 1 the air jacket l3 and the burner side wall i9. 50 The rings 3ll'are spaced apart vertically and are so located that at least one row of primaryair inlet openings 2| is included between two adjacent rings.- The rings 3i! form with the air jacket I3 and the burner side wall a plurality of 5 vertically separated air compartments 3|, 321, 33

' The same ference in pressure between the burner andthe exterior will change, thus vary- Icause the bellows to elthe depending upon which way the pressur and 34. The lowermost compartment al is open at all times to the atmosphere through the openings between the legs II. The other three compartments 32, 33 and 34 are provided with air inlet ducts 35, 36 and 31, respectively. The ducts are closed by pivotallymounted closures 38, 39

and 40, respectively. The closures are pivoted within the air inlet ducts on transverse pivot shafts located slightly above the centers of the closures.

At one end of the pivot shaft of closure 38 is a crank arm 4| which extends laterally therefrom. A similar crank 42 is attached to the pivot shaft of closure 39, while a third crank 43 secured to the shaft of closure 40.

Pivotally mounted on a bracket 44-rigidly secured to the casing i is a bell crank 45. One

end of the bell crank 45 is pivotally connected to a downwardly extending link 46. The lower end of the link 45 is rigidly attached to a Sylphon bellows 41 which is connected by means of a to the interior of the casing I0. The upper end of the bellows 41 is connected to a housing 49 through which the link 45 extends. The link 45 is freely movable relative to the housing d9.

The lower end of the housing 49 is connected to a rod 56. Rigidly attached to the rod 50 are three U-shaped closure operators E, 52 and 53. The closure operators are spaced from each other in a vertical direction and are adjustable on the rod 50. The closure operators extend laterally from the rod 50 a distance sufficient to position their upper surfaces beneath the free ends of the respective crank arms M, 32 .and- Q3.

Rigidly attached at one end to the side wall of the casing I0 is a bi-metallic strip 5%. The strip 54 is so constructed that it is adaptedto bow toward the left, or to the position shown in dotted lines in Figures 1 and 2,.as the temperature of the casing l0 increases. The upper or free end of the bi-metallic strip 54 slidably contacts the arm 55 of the bell crank 45.

When the burner shown in Figures 1 to 3 is operating at low fire the closures 30, 39 and 40 will all be closed and all the air necessary for combustion of the fuel will enter the lower compartment 3i through the bottom of the casing '50 and then pass into the burner through the two bottom rows of air inlet openings 2 I;. Now, if the quantity of fuel admitted tov the burner is increased by opening the metering device, the temperature of the burner and easing will rise, thereby causing the bimetallic strip 54 to bend to the left slightly and raise the rod 50 by rotating the bell crank 45 in a clockwise direction. The lower closureoperator 5! will then strike the crank arm M and rotating the same in a clockwise direction will open the closure 38. Air'will then be admitted to the row of air inlet openings 2I the rod 50 still farther, further opening the closure 38 and'causing the closure operator 52 to strike the crank arm 42 and open closure 39.

If at any stage of operation of the burner the draft in the chimneytends to fluctuate. the difing the pressure on the bellows 41. This will r expand or contract,

'60 which communicate with the compartment 32. A still further increase in the oil flow will raise I situation will occur with respect to the crank arm 43 and closure 40 if the fuel supply is increased still more.

interior of the e varies 75 and either raise or lower the rod 50, thereby tending to open or close any of the closures 38, 39 and 40 which are partially iopened. For example, if the draft increases, bellows 41 contracts, thus lowering rod 50 and allowing the open closures to close slightly and decrease the quantity of air admitted to the burner. It will thus be seen that provision is made for maintaining a constant supply of air at any stage of operation'of the burner.

The modification shown in Figure 4 is another form of thermostatically actuated air control means which is operated by changes in temperature within the burner. The device shown in Figure 4 consists of a casing I00 having a burner I0! therein or exactly the same type as that pre- 2o communicate with the atmosphere through ducts I 06, I07, and I08, respectively. Each of the ducts' is adapted to be closed by means of a pivoted closure I09, HQ and iii. A bimetallic strip M2 is secured at one end to the duct 16 and its free end is connected by a link M3 to a crank ti t rigidly secured to the closure $09. A similar bimetallic strip H5 is connected to the closure llil'in the same manner and another bimetallic strip M5 is connected to the closure L'u, The bimetallic strips H2, H5 and H5 are resilient.

The bimetallic strips H2, H5 and H6 are designed so as to be actuated at difierent temperatures of the burner. Thus, at low fire all of the closures E09, M0 and iii are closed, but as the fuel supply is increased and the temperature of the burner rises, first the strip l IE will open the closure lot to admit more air to the burner. In a similar manner strips H5 and H6 will actuate the closures H0 and HI respectively to admit co more air to the burner at still higher levels.

The three closures I09, HE and iii are piv-' oted on horizontal axes slightly above the centers of the closures. Therefore, when the burner is operating at any stage and the draft on the burner tends to increase, the difference in pressure between that on the lower half of the 010- sure and that on the upper part will tend to rotate the closure toward closed position. The resiliency of the bimetallic strips H2, H5 and H5 will yieldingly permit such rotation. On the other hand, if the draft decreases the closure will be opened slightly by the resilient bimetallic strips. In this manner the supply of air to the burner at any particular stage of operation thereof will be maintained substantially constant.

From the foregoing itwill be seen that this invention provides'means for automatically coordinating the air supplied to the burner with.

the fuel supplied because an increase in fuel is followed by an increa burner and combustion chamber, which is in turn followed by an increase in the air supply. Furthermore, the air is delivered to the-burner at only thoseparts in which vaporization, premixing and combustion occur. When combustion occurs well down in the burner,'air is not admitted above the fire where it only wastes heat.

In addition; the air control means compensates for changes in the draft on the burner which might tend to upset the operation. thereof.

invention is indicated in the r The scope of the appended claims.

1. Combustion apparatus comprising a burner cf the vaporizing pot type having se in temperature of thea plurality of vertically separated groups of spaced apart air inlet openings in the side wall thereof, means for delivering fuel to the burner including fuel regulating mechanism, means separate from each other for controlling the admission of airto each of the upper groups of air inlet openings, each of said means comprising-an adjustable airregulating valve spaced from the burner side wall and means including a thermostat in heat exchange relation to the combustion apparatus connected to said valves for successively opening the valves in order from the lowermost to the uppermost and for closing the same in the reverse order as the temperature of the burner increases or decreases respectively.

2. Combustion apparatus comprising a burner other-for controlling the-admission of air to each of the upper groups of air inlet openings, each of said means comprising an adjustable air regulating valve spaced from the burner side wall, a. thermostat located in heat exchange relation to the combustion apparatus, and means connected to the thermostat and successively engageable with said valves upon an increase in temperature of said thermostat for successively opening said valves in order from the lowermost to the upper-, most and upon a decrease in temperature permitting the valves to close in the reverse order as the temperature of the thermostat is decreased.

3. Combustion apparatus comprising a burner of. the vaporizing pot type having a plurality of vertically and horizontally spaced apart air inlet openings in the side wall-thereof, a plurality of independent air compartments surrounding the burner in sealed engagement with the side wall, each compartment having an aperture therein for the admission of air thereto, a closure for the aperture in each-ofv the upper compartments for regulating the air admitted therethrough,

' means for delivering liquid fue1 to the burner in regulatable quantities, a thermostat connected to each of said closures and located in heat exchange relation with the burner, said thermostats being successively operable upon predetermined successive increases in the temperature of the burner whereby to open said closures in order and upon predetermined successive decreases'in the temperature of the burner to permit closing of the valves in the reverse order.

4. Combustion apparatus comprising a burner of the vaporizing pot type having a plurality of vertically and horizontally spaced apart air inlet openings in the side wall thereof, a plurality of vertically arranged separate air compartments surrounding the burnerin sealed engagement closure in the aperture in each of the upper compartments for regulating the air admitted therethrough, means for delivering liquid fuel to the burner in regulatable quantities, and thermostatic means positioned in heat exchanging relation to fuel delivered to the burner vertically arranged separate air compartments is respectively increased or decreased.

5. Combustion apparatus comprising a burner of the vaporizing pot type having a plurality of vertically and horizontally spaced apart air inlet openings in the side wall thereof, a plurality of surrounding the burner in sealed engagement with the side wall, each compartment being in communication with some of said air inlet openings, each of said compartments having an aperture therein for the admission of air thereto, a

closure in'the aperture in each of the upper com partments for regulating the air admitted there--,

through, and means for delivering liquidfuel to the burner in regulatable quantities, and thermostatic means positioned in heat exchanging relation to the combustion apparatus forsuccessively opening the closures in orderfrom the lowermost to the uppermost closure and for closing the same in the reverse order as the quantity of fuel delivered to the burner is respectively increased or decreased, and a connection between said means and said closures, said connection including mechanism tending to open or close said closures under the influence of changes in draft on the burner.

6. Combustion apparatus comprising a burner of the vaporizing pot type having a plurality of vertically spaced apart groups of ai inlet openings in the side wall thereof, means for delivering liquid fuel to the burner in regulatable quantities whereby to vary the level of the zone in which combustion of the fuel is initiated, means sepa the combustion apparatus and connected to the during the combustion period as the quantity-of the supply of fuel.

tion to the combustion apparatus for moving said valves to increase or decrease the quantity of air admitted to the burner in accordance with an increase or decrease respectively in the rate of combustion to maintain a substantially constant ratio of fuel and air within the burner during the combustion period, irrespective of variations 7. Combustion apparatus comprising a burner of the vaporizing pot typehaving a plurality of vertically and horizontally spaced apart air inlet openings in the side wall thereof, a plurality of vertically arranged separate air compartments surrounding the burner in sealed engagement with the side wall, each compartment being in communication with some of said air inlet openings, each of said compartments having anap erture therein for the admission of air thereto, a closure for the aperture in each of the upper compartments only for regulating the air admitted therethrough, means for' delivering fuel to the burner in regulatable quantities, and thermostatic means connected to the closures for opening and closing the latter to maintain a substantially constant ratio between the fuel and air supplied to the burnerwhen the burner is operating, said last named meanssuccessively opening the closures in order from the lowermost to the uppermost closure and closing the same in the reverse order as the quantity of fuel delivered to the burner is respectively increased or decreased by successive predetermined quantities.

8. Combustion apparatus comprising a burner of the vaporizing pot type having a plurality of vertically separated groups of spaced apart air inlet openings in the side wall thereof, means for delivering liquid fuel tothe burner in regulatable uantities whereby to vary the rate of combustion in the burner, means for regulating the admit--v sion of air to the burner through certain of said groups of openings including movable valve means located outside of said burner and spaced from the side wall thereof, and thermostatic means in heat exchange relation with the appathe burner decreases. v

10ml W. MILLER.

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