US3004589A - Electric igniter - Google Patents

Description

Oct. 17, 1961 c. E. HAJNY 3,004,589

ELECTRIC IGNITER Filed Feb. 20, 1955 INVENTR.

United States Patent AOfiice 3,004,589 Patented Oct. 17, 1961 3,004,589 ELECTRIC IGNITER Charles E. Hajny, Milwaukee, Wis., assigner to Basu Inc., Milwaukee, Wis., a corporation of Wisconsin Filed Feb. 20, 1956, Ser. No. 566,703 3 Claims. (Cl. 158-115) This invention relates to improvements in electrical igniters for gaseous fuel burners.

In igniters of the type utilizing an electrical resistance element heated to a glowing temperature for ignition of gaseous fuel, one of the more common causes of inoperativeness is failure of said resistance element. Burn out of a resistance element of this type results from excessive temperatures which can be brought about, for example, as a result of excessive or prolonged energization, catalytic action of the gases with the resistance element, or by heat supplied to said element from an external source, for example from a burner flame.

It is a general object of the present invention to provide an improved electric igniter of the type utilizing an electrical resistance element in which system the problem of frequent element burn-out has been overcome.

More specifically it is an object of the invention to provide an improved igniter of the class described wherein the environmental structure surrounding the resistance element and the orientation of said element are such that said element is eliicient and positive in its operation, but is not exposed directly to the burner flame once the fuel has been ignited at the burner.

Another object of the invention is to provide an electric ignition system which is characterized by its simplicity in construction, economy in manufacture, and its effectiveness in use with new and beneficial results which will hereinafter appear.

Further objects and advantages of the invention will become apparent as the description proceeds, reference being had to the accompanying drawing showing the construction of an illustrative embodiment of the invention and wherein:

FIG. l is a side elevational view of a thermo-electric generator, a pilot burner and the improved igniter assembly;

along the line 2-2 of FIGURE l; and

FIGURE 3 is an enlarged vertical sectional view taken along the line 3-3 of FIGURE 2.

Referring more particularly to FIGURE l of the drawing there is a main burner 11 and a coacting pilot burner 12. An electric igniter 22, to be described more fully hereinafter, is disposed in igniting relation with respect to the pilot burner 12.

A thermoelectric generator 57 is subject to the heat `of the flame of burning fuel at the pilot burner 12.

The igniter 22, pilot lburner 12 and thermoelectric fgenerator 57 may form a composite assemblage as shown in FIGURE l. A generally U-shaped bracket 74 is provided with spaced parallel arms 75 and 76 and is suit- ;ably mounted adjacent the main burner 11. The arms 75 :and 76 of the bracket 74 are formed with aligned apertures for removably receiving the generator 57, which may take the form of a thermocouple, the latter being iixed in operative position by a connector nut 77 threaded into the aperture therefor in the arm 76 Fixed in a suitable aperture in the bracket arm 75 is a tubular burner body 78 having an open lower end and having its upper end provided with burner ports 85 and 85a connected by a slot 85b. The port 85a is adapted to direct a stream of fuel laterally toward the generator 57 and the main burner 11, and the port 85 is adapted to direct a stream of fuel laterally toward the igniter 22. The bracket arm 76 is formed with a suitable aperture for threadedly receiving a fuel inlet fitting 79 having a tubular portion FIGURE 2 is an enlarged vertical sectional view taken extending into the open lower end of the burner body 78 1n annularly spaced relation with respect thereto to provide an annular air inlet opening. A pilot burner fuel supply conduit 80 connects the fuel inlet fitting 79 with a suitable source of fluid fuel under pressure.

The igniter assembly 22 preferably comprises a bracket or mounting plate 81 having one end formed with an aperture through which the burner body 12 extend-s, said bracket preferably being fixed, as by brazing, to said burner body in a plane normal to the axis of said body as shown in FIGURE l. The bracket 81 has an upturned outer end, and a generally channel shaped member 82 is fixed at one end to the upturned end of the bracket 81 and extends inwardly parallel to said bracket to a downwardly angled inner end portionV 83 terminating in a depending portion 84 Jfixed to the bracket 81. The upper surface 86 of the portion of the member 82 parallel to the bracket 81 is generally in alignment with the axis of the discharge port for directing a fuel stream toward the igniter. The member 82 is also formed with an aperture 87 in the surface 86, the margin of said aperture being defined by an upwardly extending generally frusto-conical lip 88 which preferably has relatively sharp upper and lower edges 88a and 88h respectively.v

The bracket or plate 81 is formed with an aperture 89 in axial alignment with the aperture 87, and fixed within said aperture is an externally threaded sleeve 90 having a coaxial bore 91. The sleeve 90 is formed at its lower end with a radially inwardly directed annular flange defining an opening 92 which is coaxial with the bore 91 and which is circular except for a flat surface 92a at the side thereof adjacent the burner 12. The opening 92 preferably has a diameter only slightly smaller than that of the bore 91, and removably disposed within said bore and opening is a cylindrical glow plug 93 having au outer diameter only slightly smaller than that of the opening 92 and also having a flat surface 94 mating with the flat surface 92a of said opening. The coaction of the at surfaces 92a and 94 which constitute cooperating shoulder means affords rotational orientation of the plug 93 for a purpose to become apparent hereinafter, and by preventing rotation of the plug 93, it facilitates tightening of the lead connector nut 110.

An externally knurled and internally threaded nut 95 has a radially inwardly directed annular end flange 96 received in a complementary peripheral groove at the lower end of the glow plug 93 to provide a connection permitting relative rotation between the nut 95 and the plug 93, but preventing any substantial relative axial movement therebetween. The internal threads of the nut 95 engage the external threads on the sleeve 98, and the peripheral chamfer 98 at the upper end of the plug 93 mates with the annular under surface of the lip -38 to deline the axial position of the plug 93. The nut 95 thus affords means for removably securing the plug 93 in the operative position shown independent of the connection thereto of lead 43 by nut 110.

The plug 93 is formed with a reduced diameter bore 99 and has an internally threaded enlarged counterbore 100 extending inwardly from the lower Vend thereof as shown in FIGURE 3. An enlarged counterbore 101 also extends inwardly from the upper end of the plug 93 as shown in FIGURE 2, and a side wall portion of the plug 93 is cut away at 102 substantially the full length of the counterbore 101, said cut away portion having a width not substantially smaller than the diameter of said counterbore. Diametrically aligned with the cut away portion 102, the plug 93 is formed with a cut away portion 103 extending inwardly from the upper end thereof, said cut away portion having substantially the same width as the cut away portion 102 and having a depth substantially equal to that of the chamfer 93. The alignment of the cut away portions 102 and 103 is normal to the alignment of the plug 93 with the burner body 12, i.e. the direction of discharge of the fuel from the burner port 85. The plug 93 is also formed with diametrically opposite cut away end portions 104 and 10i/the alignmentV of which is normal to that of ythe cut away portions 102 and 193. The cut away portions 102, 103, 104 and S afford air inlets into the depression formed by the counterbored upper end of the plug 93 and. the-aperturedV member 82 the aperture 87 of which forms the mouth of said-depression.

The inner ends of the counterbores 106i and 1t1 are tapered as shown, and insulatably mounted Within said counterbores and the bore 99 is a headed terminal tip 115 having a frusto-conical annular surface on the upper side of the headV thereof which is complemental to the taper at the upper end of the counterbore 1% to thereby afford a centering action for said terminal tip. Terminal tip 115 has a stem projecting into the counterbore 161 and projects through the central aperture of the annular concavo-convex portion of an insulated conductor member 196 and is mechanically and electrically connected thereto, as by brazing. The member 166 also has an upstanding arm portion 107 terminating in a radially outwardly directed tip portion 168.

The upstanding aim 167 of the member 106 is positioned within the cut away portion 102 as shovm in FIGURES 2 and 3, and the upper surface of the Vont,

turned upper end 108 of said member isV preferably in substantiaily the same plane as the base of the cut away portion 103 diametrically opposite. A helical igniter vcoil of electrical resistance material 109 has end portions aligned with the periphery thereof and electrically fixed, as -by resistance welding or brazing, to the out turned end 198 of the arm 1617 and to the plug 93 respectively, the latter connection being made at the point where the end portion of the coil 1t?? overlies the base of the cut away portion 103. 1t is thus apparent that the igniter coil 1119 is disposed with its axis yextending in a horizontal direction as viewed in the drawings, and generally normal to the direction of discharge of the fuel from the burner port 85.

The coaxial lead 43 affords electrical connection between the terminal tip 115 and plug 93 and a suitable source of energizing current for the igniter 22. The lead 43 is provided with an externally threaded connector nut 11i? which is threadable into the threaded counterbore 10i? of the plug 93. It is apparent that the internal threads of counterbore 161i andthe external threads on nut 110 constitute removably connected complementary shoulder means. The outer conductor 44 of the lead i3 has its end portion adjacent the nut 11d flanged outwardly, as at 111, for engagement by the nut 11i?. An insulating washer 112 overlies the flanged end 111 and surrounds the insulated inner conductor 45 of the lead 43. A terminal tip 113 is Yelectrically fixed on the end of the inner conductor 45 for electrical engagement with the terminal tip 1125, and a spring washer 114 which is normally diametrically bowed surrounds the conductor 45 and is interposed between the terminal tip 113 and the insulating washer 112.

Upon tightening of the connector nut 110, the spring washer 114 becomes substantially flattened, and by virtue of this deformation continually exerts an inwardly acting force on the terminal tip 113 and outwardly acting force on the washer 112 and hence, through the ange 111, on the connector nut 110. The forces exerted by the spring 114 on the tip 113 and on the washer 112. are exerted at diametrically opposite points and are therefore balanced, in countradistinction, for example, to the force exerted by a split washer which exerts its force on one side only. The continual force exerted by the deformed spring washer 114 prevents loosening of the connector nut 11i) which would otherwise occur as a result of a racheting effect Vproduced by differential in expansion and contraction of the plug 93 and nut 110 as a result of temperature changes to which said parts are subjected.

The operation of the improved ignition system will now be described. The igniter coil 1097 upon energization thereof, heats to incandescence, and as the supply of fue-l to the pilot burner 12 is turned on, gas discharging from the port is directed toward the igniter member S2 and its opening S7.

The kportions of this discharged gas which impinge upon the angledup-per surface of the portion 83 of the member 82 are deflected upwardly thereby away from the opening 87, and impingement'of portions of the discharged gas against the lip 88 deflects the latter impinging portions upwardly away from the opening 87. Flow of the remaining portion of the discharged gas over the sharp upper edge 88a of the lip 88 creates eddies of fuel which turbulently ilow into the opening 37 and into depression formed therewith by the counterbore 101. Air enters the aforementioned depression through the cut away-portions 1032. and and mixes with the aforementioned eddies of fuel to Vcreate an ignitable mixture which is ignited by the heat of the coil 109 which is now owing as a result of the current iiow therethrough. Ignition of the aforementioned mixture within the counterbore 161 ignites the discharged fuel stream emitting from the port S5, and because of the slit 85b, the ame is carried to the fuel stream discharged from the port 85a. Due to the heat ofthe burning fuel at the port 85, the flame thereat may `lift upwardly out of contact with the member 32 entirely, but in any event does not ente-r the depression comprising the co-unterbore 1611. Thus, the igniter coil 109 Vis not deleteriously affected by the pilot burner frame.

The specific illustration and corresponding description is used for the purpose of disclosure only, and is not intended to impose unnecessary limitations on the claims, or to conne the patented invention to a particular use. lt is apparent that various changes and modifications may be made without departing from the spirit of the invention, and all of such changes are contemplated as may come within the scope of the appended claims.v

'What is claimed as the invention is:

l. In combination, a gaseous fuel burner formed with an outlet port for discharging gaseous fuel in a predetermined generally horizontal direction therefrom, a bracket having a surface portion formed with an opening facing in a direction substantially normal to the direction of said fuel discharge, a sleeve fixed to said bracket substantially coaxial with said opening, an igniter plug coaxially positioned within said sleeve and having recessed opposite end portions, one of which is disposed at said opening to form therewith a depression, an insulated terminal tip fixed within the other recessed end portion of said plug, an helical igniter coil carried by said plug within said depression and dis-posed with its axis extending substantially diametrically across the end of said plug adjacent said opening, one end of said coil being connected in circuit with said plug, and the other end of said coil being connected in circuit with said insulated terminal tip, said other end of said plug being formed with shoulder means for removable connection with complementary shoulder means of a coaxial lead connector, and means for removably seouring said igniter plug in operative position within said sleeve independent of said removable connection of said plug and lead.

2. In combination, a gaseous fuel burner formed with an outlet port for discharging gaseous fuel in a predetermined generally horizontal direction therefrom, a bracket having a surface portion formed with an opening facing in a direction substantially normal to the direction of said discharge, a sleeve fixed to said bracket substantially coaxial with said aperture, an igniter plug coaxially positioned within said sleeve and having recessed opposite end portions, a nut threaded on said sleeve and engaging said plug for removably positioning saidplug in operative position within said sleeve with one of said recessed ends disposed at said opening in abutment with said bracket and with said opening forming a depression, an insulated terminal tip fixed Within the recess at the other end of said plug, an helical igniter coil carried by said plug within said depression and disposed with its axis extending substantially diametrically across the end of said plug adjacent said opening, one end of said coil being con nected in circuit with said plug, and the other end of said coil being connected in circuit with said insulated terminal tip, said plug being formed with at least one air inlet opening through a Wall portion of the recessed end thereof adjacent said coil, said other end of said plug being formed with shoulder means for removable connection with complementary shoulder means of a coaxial lead connector independent of said plug positioning means.

3. In combination, a gaseous fuel burner formed with an outlet port for discharging gaseous fuel in a predetermined generally horizontal direction therefrom, a bracket having a surface portion formed with an opening facing in a direction substantially normal to the direction of said fuel discharge, a sleeve fixed to said bracket substantially coaxial with said aperture, an igniter plug coaxially positioned Within said sleeve and having recessed opposite end portions, one of which is disposed at said opening to form therewith a depression, an insulated terminal tip fixed Within the other recessed end portion of said plug, an helical igniter coil carried by said plug Within said depression and disposed with its axis extending substantiaily diametrically across the end of said plug adjacent said opening, cooperating shoulder means on said sleeve and plug for rotatively positioning said plug such that the yaxis of said igniter coil extends generally transversely of the direction of discharge of said fuel, one end of said coil being connected in circuit with said plug, and the other end of said coil being connected in circuit with said insulated terminal tip, said plug being formed with `at least one air inlet opening through a Wall portion of the recessed end thereof adjacent said coil, said other end of said plug being formed with shoulder means for removable connection with complementary shoulder means of a coaxial lead connectorJ and means for removably securing said plug in operative position Within said sleeve independent of the removable connection of said plug and lead.

References Cited in the tile of this patent UNITED STATES PATENTS 2,316,910 Weber Apr. 10, 1943 2,329,888 Eskin et al. Sept. 21, 1943 2,384,797 Cerney et al. Sept. 18, 1945 2,388,909 Douglas Nov. 13, 1945 2,391,506 Pearson Dec. 25, 1945 2,575,113 Lennox Nov. 13, 1951 2,751,973 Meusey June 26, 1956 2,761,947 Rice et al. Sept. 4, 1956 2,768,677 Traver Oct. 30, 1956

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