US2056146A - Burner starting device and wick therefor - Google Patents

Description

Sept. 29, 1936. R. M. SHERMAN BURNER STARTING DEVICE AND WICK THEREFOR F'lled Jan 6, 1934 2 Sheets-Sheet l Sept 29, 1936- R. M. SHERMAN 2,056,146

BURNER STARTING DEVICE AND WICK THEREFOR Filed Jan. 6, 1954 2 Sheets-Sheet 2 Patented sept. ze, 1936 UNITED STATES 2,056,146 BURNER STARTING DEVICE AND "wrox THEREFOB neusten M. .snel-man, Glastonbury, conn., as- ,signor to The Silent Glow vOil Burner Corporation, Hartford, Conn.,- a corporation of Connecticut Application January 6, 1934, Serial No. '105,549

13 Claims. (Cl. 158-790) This invention relates to burners employing liquid fuel (for descriptive purposes herein referred to as oil.) and more particularly, though not exclusively, those in which a wick is employed for 5 starting or other purposes. ,Y

. The invention is herein illustrated in connection with a burner of the combustion tube type in which an oil-saturated nre-resisting wick is lighted and used to preliminarily heat the burner,

l after which the burner becomes self-vaporizing and the wick ordinarily ceases further to function.

In starting burners of `this type the initial lighting of the wick is a. troublesome and awkward l operation usually requiring the insertion of a lighted taperrbetween the combustion tubes. It is also uncertain, often requiring repeated attempts before the wick is lighted, and usually results in a localized, slowly spreading flame, with an uneven combustion persisting for some length of time. j

One object, among others, of the present invention is to provide electrical means for lighting the wick of an oil burner comprising a resistance heating element preferably so disposed that when current is caused to pass through the resistance element, the oil throughout a substantial length of the wick is quickly vaporized and ignited, with a. resulting evenly distributed flame throughout the entire extent of the wick.

Another object is to accelerate the full fire operationof a combustion tube burner after the wick has been lighted.

Another object is to provide means for automatically cutting oi the source Vof electric current when the proper stage has been reached in the operation of the` burner.

These and other objects of the invention will be best understood by reference to the following l4,0 description when taken in connection-with the accompanying illustration of one specific embodiment thereof, while its scope will be more particularly pointed out in the appended claims. In the drawings: 4 Fig. 1 is a plan view of a burner' employing one iorm of the invention, the parts above the base and portions of-the wicks being broken away;

Fig. 2 is a central sectional elevation of the same burner taken on the line 2-2of Fig. 1, intermediate portions of the combustion tubes being broken out;

Fig. 3 is an enlarged sectional kelevation showing the two opposite ends of the outer one of the two wicks with their electrical connections to the terminals carried in but insulated from the burner base; Fig. 4 is a plan in partial section taken on the line 4 4 of Fig. 3;

Fig. 5 is' a sectional elevation on the line 5-5 5 of Fig. 3; Fig. 6 is a side elevation of a portion of a wick having the resistance heating element in a different relationship from that shown in Figs. 1 to 5; 10

Fig. 7 is a sectional elevation taken through the wick shown in Fig. 6; and

Fig. 81s a plan view, Fig. 9 a side elevation, and Fig. 10 a sectional elevation showing a portion of a wick having the resistance heating element in l5 a still different relationship; while Fig. l1 is a fragmentary detail in section to a greatly enlarged scale showing a preferred form of fuel groove.

Referring to the drawings and rst describing the specic form of burner in connection .20 with which one form of the invention is herein shown, the burner (Figs. 1 and 2) is provided with a base I I in the form of a casting having an outer generally annular portion and an inner of the inner portion also having an 'upstanding ring-like ilange 2| spaced from but concentric with the ange I9. The anges I9 and 2I 35 together with the connecting bottom jwall of the base casting form a relatively wide annular compartment or channel 23 on the bottom of which is e raised wall or rib 25 extending around said channel but interrupted at intervals. Oil is 40 adapted to be delivered to the channel 23 by a pipe connection 21 opening into the bottom wall of the channel through the oil inlet opening 29, the latter being disposed between therib 25 and the ange I9. 4 The outer annular portion of the base casting presents an outer fuel compartment in the form of a channel 3| formed between` the upright spaced ilanges 33 and 35, the outer channel being of lesser radial' Width than vthe channel 23. 50 The outer channel 3l is connected to the inner fuel channel 23 by means of supply ducts 31 formed in the webs I3 so that a free circulation of liquid or vaporized oil takes place through both fuel channels. The top of the wide chan- 55 rectly into the space between the flange 2| and the edge of"\\the cover plate 39.

The edgel of the cover plate` has anout-turned lip-on which there is supported a perforated sheet metal cylinder 4i constituting the inner oneof a pair of combustion tubes. A similar but larger concentric cylinder 43 is removably seated on the outer shouldered edges of the fiange 2l so that there is provided between the two cylinders an elongated combustion chamber 45 alignedwith and constituting an extension of theouter uncovered edge of the wider channel 23. Two concentrically spaced perforated sheet metal cylinders 41 and 49` are like-A wise removably seated on the inner and outer shoulders, respectively, of the flanges 33 and 35, providing between them a combustion chamber 5i having a relation to the outer fuel channel 3| similar to -that of the combustion chamber 45 to the outer portion of the channel 23.

A removable annular top plate 53 is provided with its edges resting on the tops of the sheet metal cylinders 4 3 and 41 to close the top of the annular air space therebetween, and a discshaped closure 55 with itsedges resting on the upper edges of the cylinder 4i is similarly provided to close the top of the central air chamber, leaving, however, annular openings in the,

tops of the two combustion chambers 45 and 5| for the escape of the products of combustion.

A burner of this type is commonly started by igniting an oil saturated wick usually comprisling a fabricated strip of asbestos.' the strip' being cut so Vas to rest in the fuel compartment or channelwith its upper edge entered into the bottom lof the overhead 'combustion chamber.

In the'illustrated device two such wicks .51 and 59 are shown, the first located in the outer fuel channel and the other in the inner fuel'chansnel. The inner wick 59 may have the portions coinciding with the ports 31 cut away to leave such p orts unobstructed.

When the burner is to be started, oil is admitted through the inlet port 23 and enters the wide channel, flowing thereover within the raised rib 25, through the openings therein to the outer portion of the channel, and through the ducts 3'l into Athe outer fuel channel 3l, penel trating the bottom edges of both wicks and saturating the bodies thereof. Tjhe wicks being then lighted, the burner begins to heat, and when the required vaporizing temperature is reached the liquid oil becomes vaporized on entering the channel 23 beneath the cover plate 39, the covered portion of s aid channel constituting a vaporizing space. Combustion is then carried on to an increasing degree independently of the wick, and finally completely through the oil vapor passing fromthe vaporizing chamber beneath the edge' of the cover plate into the inner combustion chamber and into the outer combustion chamber through the ducts 31,"and

' the wicks ceasing to function when the burner 'operates under full fire.

To ignite the wick at any time after it has been saturated with oil, there is provided in the illustrated form of the invention a resistance heating element or resistor, herein carried by and incorporated in the wick itself. This is in the form of a conductor 5I threaded lengthwise the wick. While various relationships of the resistance element to the wick may be employed, two other examples of which are hereinafter given, in the form shown in Figs. 1 to 5 the conductor is threaded through the material of the wick and spirally over the upper edge thereof. This Places the resistance heating element in such a relationship and close proximity to the wick and edge thereof that whenincluded in an electric circuit it provides a continuous conducting path in which the heating current is localized at or near the edge of the wick and is capable of being brought to a suillcient heat to vaporize the oil in the saturated wick throughout substantially the entire length thereof and to ignite the oil vapor with substantial uniformity Vthroughout the' entire extent of the annular space in which the wick is positioned, thereby providing a starting fiame of substantially uniform volume. Combined with the resistance heating elements are terminals positioned in but insulated from the base to which the ends of the conductor may be electrically connected and through which electric heating current may be supplied at will.

In the illustrative embodiment of the invention each of the two wicks carries a resistance heating element, but, if desired, one wick only may be associated with the resistance heating element and the ignition-of that wick may belrelied on to ignite -the remaining wick or wicks.

In the illustrated embodiment of the invention, the wicks, resistance heating elements and connections and terminals therefor are substantially the same in construction and arrangement in the case of both the outer and inner wicks 51 and 59,

except as hereinafter mentioned, and specific description thereof will be confined to the outer fere with the heating function of the conductor i 5I. Asbestos being a non-conducting' material,

in the illustrated form of the invention, where the conductor is spirally threaded through, the

asbestos in the manner indicated, the ,heating current is conilned to the conductor and localized at or near the edge of the wick.

Referring to Figs. 3, 4, and 5, the opposite ends of the wick as it lies in the groove 3l are separated by a space in which there is provided a pair of' binding posts 53,' 53 mounted in but insulated froma raised lug 55 formed in the base and filling the groove .3L Beneath the top fof each binding post and electrically connected thereto, but insulated from the base, is a clip $.61 of conductive metal and of L-shaped cross section through which, by means hereinafter described, connec- A tion is made from one binding post to one end of the resistance heating element 8l and'throgh the other binding post 'to the opposite end of said element.

. Each binding post is connected to arconductor 59, which conductors are included inan electric circuit, cliagrtunmatically represented at 1i in Fig. 3, the circuit including a sourcev of current 13 and a switch 15, so that when the switch is closed heating current is passed through the resistance heating element 6|. In practice connections maybe made to the usual house lighting circuit and the Voltage stepped down by a suitable transformer.

The conductors for the resistance heating elements may be connected either serially or in multiple in the same circuit 1|, or may be connected to separate sources of current as desired.

Combined with the electrical igniting device there is also provided means for effecting the automatic cut-out of the electric circuit after the lapse of an adequateinterval and herein when the wick is fully ignited'and the burner` is in operation. Such automatic cut-out may be provided -by various means including those operating on other than athermostatic principle, but in the illustrative example there is provided for this purpose a thermal responsive device comprising a connection 11 of bimetallic thermostatic metal, such that, when the burner is cold and prior to the lighting of the wick, electrical con-I nection is maintained, but, after the burner has attained a given stage of operation, the igniting current is cut off. The automatic cut-out device may be positioned in any suitable part of the burner. The heat generated soon after the burner becomes lighted will be suiilcient to actuate a thermal responsive device' having easily obtainable qualities of response if such device is located contiguous to any part of the base, the combustion tubes, or any other of the burner parts illustrated. In the illustrative example, however, thel bimetallic connection 11 is positioned immediately above the groove 3| at the bottom of the chamber 5| and connected between the binding posts 63 and the end of the resistance heating element 6|, its relationship 'being -such that, after the wick has been lighted, the connection of the resistance heating element is automatically broken.

In the present instance a similar connection 11v is provided for each of the two binding posts 63, description being made of one only. If desired, however, a single make and break device only might be used at one end of the resistance heating element and a permanentconnection be employed between the opposite end thereof and the remaining binding post. Or, in the case of two or more wicks, the resistance heating eler ment for a plurality of wicks may be connected in series or in parallel and a single thermal responsive device employed to cut oil? the current from the resistance heating element of all said wicks.

Referring again to Figs. 3 to 5, inclusive, the bimetallic connection 11, as illustrated, is of curved or U-shaped form and has one leg thereof abutting against the edge of the wick and electrically connected to the end of the conductor 3|. In that position it is held by the metallic sheath 19 of U-shaped cross section, which sheath overlies the vertical edge of the wick and is secured thereto by a pair of pins 8| passing through the* sheath and the wick, so that the wick 51, conductor 6|, connection 11 and sheath 19 are permanently bound vand secured together. The pins 8|, vwhile extending through the wick and sheath. protrude outwardly slightly beyond the latter. The leg of the connection 11 is insulated from the sheath by an insulating lining 33. I'he opposite protruding ends of .the pins 8| fit and may be inserted into the tops of the vertical grooves or slots IB formed in the flanged walls 33 and 35 of the base, thereby holding the end of the wick and likewise the bi-metallic connection 11 in fixed relationship to the binding posts 63 and the connecting clip 61.

The connection 11 curves upwardly and outwardly from the wick edge and thence downwardly, the downwardly curved leg thereof, when the burner isI cold, pressing in close electrical contactI against the upstanding part of the L- shaped clip 61. The shape of the connection 11, however, is such that it has a substantial opening movement when subjected to a high temperature (indicated by dotted lines in Fig. 3), so that, after the wick is lighted and the burner heats up, the resulting combustion in the bottom of the combustion chamber in and about the bimetallic connection 11 causes 'the latter to expand and open, breaking the contact between the depending leg thereof and the clip 61 and opening the circuit of which the conductor B I forms a part. 'I'he thermostatic connection 11 is located in the zone of combustionand above the level of the wick. Its cross-sectional area. and resistance are preferably such that it undergoes no such substantial expansion as to break position by slipping the pins 8| into the vertical grooves 85, giving the connection 11 a definite position with relation to the binding posts 63. The clip 61 has a slightly elongated opening where the binding post passes through it, so that if any adjustment of the clip is required to secure good electrical contact between the clip and the connection 11 the binding post may be loosened and the clip adjusted to its desired relationship.

The provision for the inner wick 59 is substantially the same as that described in connection with the outer wick 51 except that the pin 8| protrudes only on the outer wall of theI sheath and the bottom of the inner face of the sheath bears against the side of the raised rib 25 which assists in positioning the end of the wick.

In the illustrative embodiment 'of the invention, the wick is shown of such a height that the conductor 8| is held well removed from any grounding contact with adjacent metallic parts of the burner. If it is desired to employ wicks of lser height, or if it is desired to so locate the conductor that it penetrates lower portions of the wick than are shown in Figs. 1 to 5 (as, for example, in Figs. 6 and 7), or if for these or other reasons there arises the possibility of grounding'the heating element on the walls of the base, the base may be and preferably is given a superficial insulating coating by enameling the walls thereof in accordance with the disclosure in my prior Patent No. 1,848,206, dated March 8, 1932. Such coating of insulating enamel may be caused to cover the inner and top walls of the fuel groove 3|, as indicated by the heavy` black lines l2 in Fig. 2 and in greater detail in Fig. 11, so that, evenif the resistance heating element 6| should come in contaet with the walls in the starting time required,-by starting time referring to the now relatively long interval which must elapse after lighting the wick and before the full fire operation of the burner is reached. When the wick in the now prevailing type of burner is lighted, the name of the wick is relied upon to initiate combustion and build up the vaporizing capacity of the burner. continues for a substantial interval of time to be relatively feeble and to be limited in respect to intensity of combustion by the relatively small volume of oil vapor volatilized at the edge of the wick and immediately adjacent the zone of combustion.

In the described starting device, to the amount of oil vapor volatilized by the combustion at and above the edge of the wick is added a substantial and continuing increment of oil vapor vaporized by the heat communicated from the resistance heating element to the oil which is being drawn up into the body of the wick itself.

It follows that not only is the production of oil vapor from the wick itself sharply accelerated but the volume of oil vapor thrown off is materially increased at the critical period of starting, which at present is a long drawn out interval, so that the full fire operation is reached in a substantially shorter time. thermostatic device may be designed to operate at any desired range of temperature, so that by proper design of the thermostatic cut-out, the heating current through the resistance element, which provides such increased amount of vaporized oil, may be continued until any desired stage in the burner operation has been reached.

'The Amore rapid starting of the burner may be still further promoted by extending the resistance heating element further down into the body of the wick. In Figs. 6 and 7, such an arrangement is shown, the resistance heating element 89 being carriedover close to the top edge of the wick, thence angularly down to a point at the side thereof, thence through the wick, and similarly upon the opposite side thereof, and so on throughout the length of the wick.

In Figs. 8, 9, and 10 another arrangement is illustrated in which the resistance heating element 9| comprises three longitudinal portions 9 la, Bib and 9I. 'Ihe lower one, 9|, has one end attached to the connection 'l'l and extends lengthwise through the lower mid portion of the wick. It then turns reversely on itself and is prolonged to provide the serially connected portion 9 lb which extends through the upper mid portion of the wick to a point near the opposite end thereof, where it is then prolonged to provide the reversely extending, serially connected portion.9i, which interlaces the wick, in the manner shown, closely l adjacent the top edge.

In this case the portions SI and SI5 supplement the oil volatilizing action of the upper portion Sic. Such resistance heating element orelements, which are supplemental to the upper conductor contiguous to the edge, may be connected either in series,.as shown, or in parallel therewith, and maybe designed to present a different amountof resistance to the passage of the current to secure differentiated heating effects in the upper and lower portions of the resistor.

In the case of the constructions shown in Figs.

6 and 'l and in Figs. 8, 9, and 10, it will be obviousl that the'wires, beside serving the function of resistors, additionally serve to reinforce the structure of the wick.

While I have herein shown and described for Such flame however,

It is obvious that the' tric circuit, of being brought to a suflicient temperature to vaporize and ignite the liquid fuel in said wick, said element comprising a conductor threaded lengthwise of the Wick, through the insulating material and over theedge thereof to provide a conductive path in which the heating current is localized at or nearA the wick edge.

2. A liquid fuel burner having a base provided with a fuel groove, combustion tube means forming a combustion chamber above said groove, a liquid fuel absorbent wick of electrically nonconducting and lire-resisting material comprising a fiat strip set on end in said groove, means for supplying liquid fuel to` said groove to saturate said wick, a resistance heating element incorporated in said wick and capable, when included in an electric circuit, of being brought to a sufficient heat to vaporize and ignitethe liquid fuel, said element comprising a conductor threaded lengthwise from end to end through the insulating material and over the upper edge of said wick to provide a continuous conductive path in which the heating current is localized at or near the edge of the wick, terminals positioned in but insulated from the base to which the opposite ends of said conductor may beelectrically connected, and

means for supplying an electric current to said conductor through said terminals.

3. An element for a liquid fue1 burner cmpris- 4. An element for a liquid fuel burner comprising a wick, a resistance heating element Aincorporated in said wick, terminals secured to opposite ends of said heating element, and a protecting sheath covering each end of the wick and holding said terminals in place.

5. A liquid fuel burner having a base provided with walls forming an annular fuel groove, a wick for said groove, a resistance heating element car- Aried by the wick, a terminal positioned in but insulated from the walls of the base, an electric connection secured to the ends of said resistance heating element and adapted to make contact with* said base terminal, and means for fixing the end of the wick in said 'groove and locating-itv with said connection in definite relation to said base terminal. l

- 6. An element fora liquid fuel burner comprising av liquid-fuel absorbent wickcomposed of fire resisting material1,'.`and\ a resistance heating element incorporated in said wick and capable, when included in an electric circuit, of being brought to a suiiicient temperature to vaporize and ignite the liquid fuel in said wick', said element being threaded through said wick and passing alternately to opposite sides thereof.

7. A liquid fuel burner having a base provided with an extended fuel groove, combustion tube means forming a combustion chamber above said groove, a fuel absorbent wick in said groove comprising a substantially at strip set on edge in said groove and extending throughout the major portion of sai-d groove, means for supplying liquid fuel to said groove to saturate said wick, a resistance heating element incorporated in said wick, extending lengthwise through a major portion of the same and capable, when included in anelectric circuit, of being brought to a suilcient heat to vaporize and ignite the liquid fuel, terminals positioned in and insulated from said base in which the opposite ends of said element may be electrically connected, and means for supplying electric current to said element through said terminals.

8. A liquid fuel burner having an elongated fuel groove therein, igniting means for said fuel burner comprising an elongated liquid-fuel absorbent wick means extending substantially coextensively with said fuel groove and presenting a portion extending above the liquid level therein, and a vaporizing and igniting element comprising a resistance heating means carried by and contacting said wick throughout the major portion of its length-and capable of being connected in an electric circuit, whereby substantially concurrent vaporization and ignition may be effected throughout the major portion of the burner.

9. vA liquid fuel burner having a metal base provided with a fuel compartment and means for supplying liquid fuel thereto, combustion tube means forming a combustion chamber` above said compartment, a fuel absorbent wicking strip cooperatively positioned in said compartment to facilitate starting, electrical means for igniting said wicking strip including a resistance heating element incorporated therewith and capable, when included in anelectric circuit of being brought to a su'icient temperature to vaporize and ignite the liquid fuel in said wicking strip, and an insulating coating over the walls of said compartment which coact with said wicking strip, insuring against short circuiting of the resistance heating element to the metal base.

10. A liquid fuel burner of the combustion tube type comprising a base provided with a fuel groove f and means for admitting fuel thereto, combustion tube means forming a combustion chamber above said groove, and a starting means in said groove comprising a resistance heating element, an electric circuit for heating said element including a contact member and a thermostatic member adapted to make contact with said contact member and break contact therewith when heated, one of Saidmembers being carried by said base and the other by said starting means, thus facilitating placement and removal of said starting means.

11. A liquid fuel burner having a base provided with an elongated fuel groove, means for supplying liquid fuel thereto, combustion tube means forming a combustion chamber above said groove,

a substantially flat strip of wicking removably positioned in said groove in operative relation to and beneath said combustion chamber and presenting a portion extending above the liquid fuel leveltherein, said wick being composed mainly of fire-resisting, liquid-fuel absorbing, non-conductive material, a vaporizing and heating element carried by the said wicking strip and in heating contact with the material thereof, and establishing a denite current path of approximately fixed resistance therethrough, a current source, connections therefrom to the burner structure, and means embodied in the structure of the burner base and detachably connected "with said element to establish an all-metallic current path from said current source and said connections through the said resistance heating element While the wick is in operative position beneath said combustion chamber, and providing for removal of said element with said wicking strip.

12. A liquid fuel burner having a base provided y with an elongated fuel groove, means for supplying liquid fuel thereto, combustion tube means forming a combustion chamber above said groove, a substantially flat strip of wicking removably positioned in said groove in operative relation to and beneath said combustion chamber and presenting a portion extending above the liquid fuel level therein, said wick being composed mainly of fire-resisting, liquid-fuel absorbing, non-conductive material, and having incorporated for removal therewith vaporizing and heating means in heating relation with the absorbent material establishing a definite current path of approximately determined resistance through said wicking strip, a current source, connections therefrom to the burner structure, and means embodied in .the structure of the burner base detachably vconnected with said vaporizing and heating means to establish an all-metallic current path from said current source and connections to the said vaporizing and heating means while the wick is in operative position beneath said combustion chamber and providing for removal of said heating means with said wicking strip.

13. A liquid fuel burner of the combustion tube type having a base provided with a fuel groove, combustion tube means forming a combustion chamber above said groove, a fuel absorbent wick -in said groove, means for admitting liquid fuel to said groove to saturate said wick, a resistance heatingelement incorporated in the wick structure for lighting-said wick, said wick and resistance heating element being removably mounted as a unit, an electric circuit including said resistancel heating element, a thermal cut-out for opening said circuit comprising a fixed contact in said groove but insulated from the walls thereof, and a bi-metallic thermostatic member serially connected to said resistance heating element and carried thereby for removal therewith as a unit, said member normally having contact with said xed contact and said contacts being out of,

but said bi-metallic member extending into, thev zone of combustion.

f RALLSTON M. SHERMAN.

Images