US2293697A - Flame propagator for pilot burners - Google Patents

Description

Aug. 25; 1942. L, s., CHADWICK 2,293,697

V FLAME PROPAQATOR FOR PILOT BRNERS w! y l INVEroR, y y BY Le@ ChdWiCK'.

. ATroRNEYx Aug.v 25, 1942., L. s. c HADwlcK LAMEROPAGATOR FOR PIIOT BURNERS vFiled oct. 2o, 1939 4 sheets-sheet'z A Fmi.

' 50 INVENTOR BY Lee SChdwicK I 1 5w, l ATroRNEYs.

ilg 25, i942 1..I s. cHADwlcK 2,293,697 l FLAME PROPAGATOR FOR PILOT-BURNERS Filed oct. 2o, 1959 4 shets-sheet 3 INVENTOR.

"F16, BY Lee SCJnadwic ATTORNEYS.

Aug. 25, 1942. L. s. cHADwlCK FLAME APRQPAGATOR FOR PILOT BURNERS f 4 Sheets-Sheet 4 Filed Oct. 2o, 1939 INV ENT OR. Lee 5. Chadwcl ATToRNEYx Patented Aug. 25,1942' l FLAME PROPAGATOB Fon. PILOT Bu'nNEns Lee S. Chadwick, Shaker Heights, Ohio, assig'nor to Perfection Stove Company, Cleveland, Ohio, a corporation loi' Ohio, f'

Application october zo, 1939, serian No. 306,428

(ci. y15s-91) 11 claims.

This invention relates, generally, to burners of the so-called pan ontray class in which the fuel is burned from a pool or sump, the present inv/ention being characterized by a structure defining a pilot re space and a higher fire space, with means for communicating combustion from the pilot ame to the fuel in the higher re space. y I

` Such a burner, referred to as being of the bowl or pot type, 'is disclosed and claimed in an application led by Theodore B. Focke and Joseph R. Kirkpatrick on July 14, 1939, Serial No. 284,544;` and the' present invention, shown herein as embodied in such a structure, more particularly relates to improvements inthe flame propagating means.

The broad purpose of the i.invention is to provide, in combination with liquid fuel burning apparatus including a pilot fire space and a higher re space (with means for-feeding fuel tb the pilot fire space and occasionally to the higher fire space and for preventing the fuel from rising within theflatter. space above a maximum level), flame propagating means consisting of a capillary conductor or wick that dips into the fuel pool and extends above the maximum fuel level in the higher re space Yinto lighting relation to the pilot name.

It is a further purpose of the invention to provide, in conjunction with a bowl type vburner f characterized b'y a wall or partition that divides its interior into a pilot fire space and a higher liquid fuel Fig. 4 is a perspective view ofthe metal support and shield for the ceramic or refractoryelement that constitutes the wick proper; Fig. 5 is a similar view of the wick; Fig. 6is a section on the line 14 are like views of la further modication incorporating a wick of similar character, and Fig. 15 i is a schematic representation of the invention in# `cluding a fuel feeding and automatic control i fire space,`an eiiicient and reliable means that is smooth and practically instantaneous of action for communicating or transmitting combustion from the pilot llame to fuel in the higher fire space so that there is no perceptible interruption in operation when the burner goes from pilot to higher re, and which means is simple; is quick and convenient of installation; is inexpensive, and is durable and substantial so as not to be liableto injury when the burner is cleaned.

Additional objects and advantages will appear as I proceed to describe the invention in detail by reference to the accompanying drawings wherein Fig. 1' is a fragmentary sectional view, partly in elevation, of a liquid fuel combustion apparatus incorporating'a bowl type burner having an enclosed pilot burner equipped with the wick of my invention in its present preferred form; Fig. 2 is a side elevation of the wick and the adjacent portion of the pilot burner,v this and the remaining views being on a scale considerably enlarged over that of Fig. l; Fig. 3 is a iront elevation, withn parts broken away, of what is shown in Fig. 2; 55

means.

The apparatus illustrated in Fig. 1 comprises a combustion chamber I enclosed by a` drum or Vcasing 2,\to the apertured or annular 'bottom wall 3 of which is fastened, by means of bolts 4, a ringlike member 5. Secured, as by posts 6, to the member 5 in @spaced relation thereto, is the top wall i of the burner bowl that-is'designated generally by the reference numeral I0. The

-upper end of the peripheral Wall I i of the burner bowl is welded or otherwise attachedto the edge portion of the top wall .'I, and shown as formed and said neck is provided with perforations I1 through which secondary air is admitted to the combustion space from a surrounding air com- A .partment enclosed by a bottom Wall 2|, a

peripheral wall 22 and an inwardly and upwardly convergent top wall 23 through which the yperipheral wall 22 is joined to the ring-like member 5 in the region of the lattersconnection with the bottom wall of the combustion chamber. Air is supplied to the compartment 20, either naturally or by artificial means, through an opening 25 in the bottom wall thereof. The peripheral Wall II of the burner bowl has air inlet openings 26, and

'the top wall 1 may also be provided with air openings, as shown at 28. l

A relatively large lighting and cleanout opening in the peripheral wall II is shown as surrounded by a ange 3|, and said opening is adapted to be closed by a plug 32, which carries a.

gasket 33 for engagement with the ange 3| The plug ts within a sleeve 34 that is secured to the burner bowl about said ange 3ly the plug and sleeve having parts that cooperate to removably hold the plug in position to seal the opening 30.

Insulating shells 31 and 38 are applied to the bottom wall I2 of the bowl, and the outer shell 33 l secured.

Liquid fuel is adapted to be delivered to the burner bowl or pot through a supply pipe 48 that passes upwardly through openings in the shields 38 and 31 and the wall l2, the pipe being welded or'otherwise secured to said wall with a leakproof joint. As disclosed in Fig. l5, the supply pipe 48 is a` part of the communicative connections between the burner and a source A of liquid fuel supply, such source being represented as a tank. Fuel gravitates from said source through a pipe a, to a vessel B wherein oat mechanism, designated generally by the reference letter b and shown in dotted lines, establishes a maximum liquid level Within the portion of the system including the burner bowl, such level being indicated by the dot-and-dash line a in Fig. l.

The fuel feeding and control means shown in Fig. forms the subject matter of an application Serial No. 273,969, led May 16, 1939, by Theodore B. Focke. Reference may be had to that application for details, although said means may be described briefly as including a by-pass valve b', a metering valve b2, and valves that are automatically actuated by thermostatic elements b3 and b4 which are in the nature of'bi-metal strips, and with which are associated the respective electrical resistance heaters b5 and b". vThese heaters are in circuit with a thermostatic switch or so-called room thermostat .C, and the secondary winding of a transformer D. The primary winding d of the transformer is included in the house circuit that is represented by conductors E and F, the latter being shown as including a switch f. One side of the secondary Winding d' is connected, through a conductor d2 with the movable element c of the room thermostat, and in case of a drop in temperature below that for which the room thermostat is set, the element c swings into engagement with the contact c that is connected, through a conductor c2, with the heater be, supplying current thereto that re-A turns to-the opposite end of the: secondary winding d through a branched conductor d3 that is common to both heaters b5 and he.

Under the conditions just described, the high temperature of the energized heater be is transmitted .to the thermostatic element b4, causing the same to warp in a direction to lift a valve, -shown in part-at b", and thus increase the fuel supply to the burner so as to cause the combustion apparatus to operate at a higher fire until the heatl generated thereby so inuences the room 'thermostat as to cause it to resume neutral condition and open the circuit.v This latter condition results in de-energization of the heater bi and allows the thermostatic element' b4 to resume normal condition thereby to return the valve b7 to its former position underwhich 'only sucient fil fuel is fed to the burner to sustain medium fire and maintain, under normal conditions, a, room temperature corresponding to that for which the thermostat C- is set.

In case of a rise in the temperature affecting the room thermostat so as to cause the movable element c to swing into engagement with contact c3, current will flow from the secondary winding of the transformer through the conductor d2 and element c to contact c3 and thence through a conductor c4 to the heater b5, the current returning therefrom to the secondary winding through the previously mentioned conductor d3. Upon the heater b5 being energized, heat will be transmitted to the thermostatic element b3 causing it to warp in a direction to lower the valve that is operatively connected to it and shut off the flow of fuel tothe burner excepting such as is permitted by the adjustment of the by-pass valve b' which is sufncielnt to sustain operation of the pilot burner. The maximum flow is controlled by the metering valve b2, which may be manually adjusted through a stem b5. Also by means of this meteing valve the flow may be entirely shut olf is of a relatively slight taper, and its lower end' is tted over the flanged upper end of the section 51, the latter being comparatively shallow and flaring downwardly at a considerably greater angle than theformer section to where it terminates in a substantially vertical flange 58. openings 60 and it encloses what may be termed the pilot burner space and separates said space from the surrounding interior portion ofthe burner bowl. The wall is held in position by a suitable number of fingers that extend radially inwardly from the wall and engage the airdistributor 50. One such finger is shown in Fig. l, where it is designated 62 and is a part of a member 65 that is Welded or otherwise secured to the vouter side of the section 56 and has its lower end flared outwardly, as indicated at 56, the finger 62 the surrounding upstanding perforated wall orV partition 55) functions in much the same way as the complete burner operates at higher fire. The surrounding interior portion-of the burner bowl serves the pilot burner, at low lre, in substantially the same way as the air compartment 2U serves the burner bowl I0 at higher re.

Wl'ieny the burner is operating at low or pilot I'lre, L

primary air is admitted to the pilot burner space through the lower openings 60 producing, withv the fuel vapors, a mixture to which secondary air 'Ihe wall or, partition 55 is provided with is added through the moreele'vated openings Il and through the openings of the air distributor 50. Practically complete combustion of the fuel at low re is thus effected.

When the control means is'operated'to increase the-fuel supply, the amount of fuel in excessof that fed for pilot iire purposes flows to the 'surrounding portion of the burner. bowl; and in this lof the wick 10. Now when. any perceptible amount of fuel occupies the portion of the burner bowl surrounding the wall 55 it will be conveyed upwardly by the wick 10 and willbe vaporized by the heat thrown oi! from the surrounding metal parts creating a gas in the region of the aperture 05 which is immediately ignited by the pilot flame. causing instantaneous I communica.- tion of combustion `from the pilot flame downwardly along the .wick to the surrounding body the mediums of my invention, one form of which is illustrated in Figs. l to 6, and described as follows:

is the wick, proper, shown as rectangular inshape, preferably of ceramicA material that is sufficiently porous to 'serve effectively as a capillary conveyor or diffuser of the liquid fuel. The wick is attached to the wall 55by a shield and supporting member designated generally by the reference numeral 15. This member consists of a U-shaped attaching element 16, and a shield and supporting member 11, both being constructed of sheet metal of an appropriate thickness. The member 11`is= welded or otherwise secured to the central portion of the element 16,. with -the latter in transverse relation to the former, and at its ends the member 11 is provided with' lateral edge portions are inclined outwardly and which may be The burner bowl may be cleaned by extending a suitable implement into it and moving the implement about, and for a morethorough job, the wall 55, as well as the distributor 50, may be removed from the bowl. To remove saidwali, a suitable device may be engaged beneath-the end 08 of the member 55. In either event, the

ber 1 5, the flared edges of which project weil away from -the attaching element 18. The ends of the attaching element terminate in tongues` 80. With the wick .10 confined between the lugs slots 8| in the wall 55 and are turned over therebeyond to secure the wick `shield and supporting member to the pilot burner, the angular relation offthe' shield and supporting member to the wall 55 being determined-by the inclinationV of the ends 82 of the attaching element 15.

,While ithe shield andsupporting member 15 is thus xedly attached to the wall of the pilot burner, the Wick 10, fitting loosely thereinr as- 18 and 19 and the side branches of the attaching f element 1B, the tongues 80 are projected through beyond the sides of said wick. However, being flared, said projecting edge portions of the shield .and supporting memberdo not interfere with the 'free'functioning of the wick.

In.A the form of the' vinvention illustrated in Figs. 'I Vto 10, a wick'90," preferably a. ceramicmaterial. is enclosed within a metal shield and supporting member 8i that is desirably'constructed of one piece of sheet metal to provide a bottom 82 and'sides 93 havingA perforations 04. Flanges 95 rise from the edges'of the bottom, an-d flanges 86 project inwardly from the rear., edges of the sides 83. Extending forwardly from y fthe sides 93 are tongues 01, while the top edges -of the sidesare -provided with notches 88. l

The pilot burn'er wall 55 with which the present form of vthe invention is associated has al relatively. large rectangular opening |00 within the region of thev joint between the upper and lower sections of the wall,- and the shield and supporting member 9|,` with the wick 80 therein, is adapted to be projected upwardly within the opening .|00 from inside said wall and ar-.

ranged with the notches 08 engaged over the edge of the wall immediately above theopen-` the spacsurrounding the pilot burner it 'will' touch the wick 10 and, through capillaryattraction, be transmitted upwardly through the wick and generally diffused throughout the same from end toend.

It AWi11"be remembered that the oil level in the burner bowl is prevented from rising higher Vthanjthe maximum elevation indicated by the dot-and-dash lines a in Fig. 1 bythe float mechanism 1),' shown in dotted lines in Fig. 6, al-

though it will` be understood that during operation of the burner the oil level vseldom if ever reaches this elevation `because of the.con

' ing aperture 85 in the wall55 establishes free communication between the pilot iire space and ing |00. The parts are held in this position by the tongues 81 that are turned abruptly outwardly against the surface of the adjacent pornous of the wan luirmmediately abete the opening |00, the`wall 55 is provid with a lighting aperture |0|, and applied to he outer side of the wall above said aperturev is a baiile |02.

When fuel is present injthe bottom iof the `pilot burner spacethatis enclosed by the wall g wick 90.

1n Figs. 1 1 and l2 there is shown a form of the invention in which a wick |05 of flexible noninflammable material, such as Woven asbestos, is

clamped to the outer surface of the pilot burner vwall 55h by a metal strap |06, and bolts |01 that 4 project lthrough said wall and the superimposed parts and have nuts |08 applied to theirvinner the space adjacent and beneath the upperend ends. The wick |05 extends from the very bottom of the wall upwardly therealong to a lighting aperture 409 through which combustion is communicated from the pilot flame inside Asaid wall to the fuel vapors about the top of the wick, such condition existing as soon as sulcient fuel has accumulated about the exterior of the pilot burner wall to saturate the Wick.

According to the invention as illustrated in Figs. 13 and 14, the wall .")5c of the pilot buiner is provided with a lighting aperture H in the form of a relatively wide slot through which a wick HI of flexible non-iniiammable material, such as that above described in connection with the wick |05, is engaged. The end portions of the wick are extended downwardly along the inner and outer sides of the wall 55 to the lower edge of said wall and are clamped in this position between a metal stripiHZ on the outside and members or washers I|3 on the inside through the medium of-bolts IM to which nuts H5 are applied.

In the present casefthe wick becomes satuoneor more of the perforations 6B of said wall `may serve the purpose, thus making unnecessary a special lighting aperture; or by proportioning upper surface of. the bottom of the bowl defining the lower limits of lboth said spaces, said wall having a lighting aperture a substantial distance above its lower edge, a shield and supporting member attached to the outer side of said wall, and awick of ceramic material sustained by said member with its lower end adjacent the bottom of said wall appreciably below said maximum liquid level and its upper end in proximity to the lighting aperture, said wick having a small cross sectional area relative to that of either o`f said spaces.

3. In combination with a burner bowl, a wall dividing'the interior thereof into a pilot burner space and a higher fire space, there being means associated withthe bowl for feeding liquid fuel to the pilot burner'space and occasionally to the higher fire space, said wall having a lighting aperture a substantial distance above its lower edge, a shield and supporting member comprising a U-shaped element h aving its ends secured vto the wall and its central portion spaced outwardly therefrom, and a second element secured to the central portion of the first element and the parts differently, the vapors from the wick,

may be ignited from the pilot 'ame above the wall, all of which is obvious and accordingly specific illustration thereof is deemed unnecessary.

Having thus described my invention, what I claim is: n

1. In combination with a burner bowl, a wall vdividing the interior thereof into a pilot fire space and a higher fire space, there being means associated with the bowl for feeding liquid fuel to the pilot re space andoccasionally to the higher fire space and for establishing a maximum liquid level\adjacent the bottoms of said spaces, the fuel being adapted to be vaporized from the surface'of liquid pools in said spaces.l the unobstructed upper surface of the bottom of tional area relative to that of either of said spaces.

2. In combination with a burner bowl, a wall dividing the interior thereof into a pilot nre i ing aperture, said wick having a small cross secspace and a higher fire space, there being means associated with the bowl for feeding liquid fuel continuously during operation to the pilotv nre space and occasionally to the higher fire space and for establishing a maximum liquid level adjacent the bottoms of said. spaces, the fuel being adapted'to be vaporized from the surface o f liquid pools in the said spaces, the unobstructed extending above and below the same and pro-- vided at its upper and lower ends with-lugs di-A 4. In combination with a burner b owl, a wall dividing the interior thereof into a pilot burner space and a higher fire space, there being means associated with the bowl for .feeding liquid fuel to the pilot burner space and occasionally to the higher re space, said wall having a lighting aperture a substantial distance above its lower edge and being flared outwardly from a point below said aperture, a shield and supporting member applied to the outer side of said wall and comprising a substantially U-shaped element whose ends are attached to the wall near the aforesaid point, and a second element secured to the central portion of the first element and extending above and below the same and terminatat its ends in lugs directed toward the wall, and a ceramic \wick loosely held between the aforesaid lugs and the side portions of the 1st mentioned element with its lower end against the bottom portion of the wall and its upper end against the wall in proximity to the lighting aperture, the lateral edges of the second mentioned element flaring outwardly away from and beyond the sides of the wick.

5. In combination with a burnerbowl, a wall dividing the interior thereof into a pilot burner space and a higher fire space, there being means associated with the bowl for feeding liquid fuel to the pilot burner space and occasionally to the higher nre space, said wall having a lighting aperture a substantial distance above its lower edge and being flared outwardly from a point below said aperture, the wall having a relatively large opening extending from s, point immediately below the lighting aperture downwardly its lower end adjacent the bottom plane of-. the` wall and its upper `end within the top portion vof said opening.

6. In combination with a burner bowl, a wall dividing the interior thereof into a pilot burner space and a higher fire space, there being means that constitutes a higher nre space, the lower limits of said spaces being defined by the unobstructed upper surface of the bottom of the bowl.

- there being means associated with the bowl for associated with the bowl for feeding'liquid fuel `to the pilot burner space and occasionallyto the higher nre' space, said wall having a lighting aperture a substantial distance above its lower edge and being flared outwardly from a point below said aperture, the wall having a relatively large opening extending from, a point immediately below the lighting aperture downwardly into the place, and a ceramic wick confined within the support with its lower end adjacent the bottom plane.. of the wall and its upper end within'the top portion of said opening, and a baille secured to and extending outwardly from the wall and having a part in such relation to the lighting aperture as to deiiect the flame through toward the wick.

'3. In-combination with a burner bowl, a wall dividing the interior thereof into a pilot burner space and a higher fire space, there being means associated with the bowl for feeding liquid fuel to the pilot burner space and occasionally to the higherv re space, said wall 'having a lighting aperture a substantial distance above its lower edge, and a wick of flexible non-inflammable material engaged through the lighting aperture and having its end portions extended downwardly along the inner and outer sides of the wall,

associated with the bowl.for feeding liquid fuel to the pilot burner space and occasionally to the higher re space, said wall having a lighting aperture a substantial distance above its lower edge, and a wick of flexible noninammable materialengaged through the lighting aperture and having its end portions extended downwardlyalong the inner and outer sides of the wall and terminating adjacent the bottom of the wall, and means clamping the end portions of the wick to the wall, said means including a clamping member that extends along and gives shape to the outer end portion of the wick.

9. In combination with a burner bowl, a -pilot burner consisting of a wall removablysuppor'ted by and upon the bottom of said bowl and enclosing a pilot fire space that is thus set off from the remaining interior portion of the bowl projected therefeeding liquid fuel to the pilot iire space and occasionally to the higher fire space and for preventing the fuel vfrom rising above a level adjacent the bottom of the bowl, the vfuel being adapted to be vaporized from the surface of liquid pools in said spaces, l anda wick of absorbent ncln-inammable material carried by,

and vremovable with said wall, the wick being of small cross section relative to that of said spaces and arranged with its lower endv adjacent` the bottom of the wall below the aforesaid level and its upper end above said level in such relation to the pilot fire space as to cause fuel conducted upwardly by the wick to be ignited fromA the pilot flame.

10. In combination with a burner bowl,l a pilot burner consisting of an annular wall removably supported by and upon the bottom of said bowl and dividing the interior of the bowl into a pilot iire space and a higher re space, the lower limits of said spaces being defined by the' unob structed upper surface. of the bottom of the .having a lighting aperture a substantial distance above its lower edge. and a wick of absorbent non-inammable material carried by and removable with said wall, the wick being of small cross o section relative to that of said space'sand arranged with its lower end adjacent the bottom of the wall below the aforesaid level and its upper end in proximity to ysaid lighting aperture.

ll. In combination with a burner bowl, a pilot burner consistingV of an Y annular wall removably supported by and upon the bottom of said ber attached to the side of and removable with said wall, and a. vwick of absorbent non-inflammable` material sustained by said member with its lov'verA end adjacent the bottom of said wall below the aforesaid level and its upper end in proximity to the lighting aperture, said wick being of small cross section relative to that of each of said spaces.

LEE S. CHADWICK.

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