US2645278A

US2645278A - holthouse

Info

Publication number: US2645278A
Authority: US
Publication date: 1953-07-14
Anticipated expiration: 1970-07-14

Description

y 4, 1953 H. a. HOLTHOUSE, SR. EI'AL IGNITION SYSTEM AND MEANS FUN INITIATING COMBUSTION 0F FUEL IN A FUEL BURNER Filed April 20. 1949 2 Sheets-Sheet 1 -.n m mr m m1 NW 0 3 0% M! ,w 5 W In ww 5 |I mmkl W w WW g QWLNU mmm m 5 I 3 MM L3- |.l$.| --I| u 3 q g 3 H X i mm E NU mm hm 3 3 a g 3 o mfl WM UW w 3 NM July 14, 1953 H. B. HOLTHOUSE, sR..

IGNITION SYSTEM AND MEANS FOR INITIATIN COMBUSTION OF FUEL IN A FUEL BURNER 2 Sheets-Sheet 2 Filed April 20. 1949 1 N9 mm x mm 2 1 s l I I/// z I z 1 r I NOON/11,111, 1

X: m .2 Wm.

a-m 2: mm m m Patented July 14, 1953 ENT] OFFICE IGNITION SYSTEMv AND MEAlISi-FOR INITL' ATING OOMBUSTI BURNER IN A FUEL Harry BQI-Iolthouse, Sr., and Harry B. Holthouse, Jr., Chicago, Ill., assignors, by mesne assignments, to Harry B. Holthouse i i Application April 20, 1949, SerialNo. 88,602:

The ignition system of this invention is adapted to be used in any liquid fuel burner and is particularly applicable in initiating the combustion of fuel in a portable heater capable of operating e'fficiently under temperatures as low as minus sixty-five degrees Fahrenheit (-650 F.) with an available electrical supply limited to a storage battery having a rating of from twenty-four to twenty-eight volts. Under these operating conditions, and with the fuel as well as the combustion airchilled to minus sixty-five degrees Fahrenheit (-65 R), considerable difficulties in initiating and then maintaining heater operation are encountered in that both the temperature of the air and the fuel counteract the effective heat developed by the ignition system for igniting purposes. Stated otherwise, with a given ignition heat derived from a source of low electrical output, it is necessary that the air and fuel as well as the heat of ignition, be relatively controlled to provide for the conservation of the ignition heat against dissipation by the-cooling effects of the fuel and air, and forthe available ignition heat being sufliciently great to initiate a 'rapid'ignition of the fuel.

- It is an object of this invntionjtherefore, to

7 provide an improved system andmeansfor initiating and maintaining combustion in a liquid fuel burner. h a

Another object of this invention is to provide an ignition system for a fuel burner capable of igniting fuel, such as aviation gasoline or jet oil, under temperature conditions in the neighborhood of minus sixty-five degrees Fahrenheit (-65" R).

'A further object of this invention is to provide an ignition system for a fuel burner which is adapted to initially ignite only a portion of the normal fuel supply to the burner, and then utilize I I 2 i i having a fuelline anda source of combustion air, in which an arc discharge between a pair of electrodes is shielded from, the cooling effects of the combustion air, and, the heat developed by the arc is concentrated or. localized ina zone between the electrodes. Apart of the normal fuel supply to the burner isfed into the zone of localized'heat and ignited, with this ignitedfuel part then being directed into "the remaining portions of the fuel supply to ignite thesame, whereby to function as a pilot flame relativeto suchremaining fuel portions. a k 1 Further objects, f eaturesand advantages of this invention will become apparent from the following description when takenin connection with the accompanying drawings, in which: i Fig. 1 is a longitudinal sectional view of a space heater of internal combustion type embodying Fig. 1 withoert'ain parts removed for the purpose of clarity;

Fig. 3 is an enlarged longitudinal sectional view of the burner unit, which is shown generally in Fig. 1; T Figs. 4 and 5 are sectional detail views of the burner unit of the heater as seen on the lines 4-4 and 5-5, respectively, in Fig. 3; and

Fig. 6 is a diagrammatic showing of an electr i'cal circuit for the ignition system of this invention.

With reference to the drawings, the ignition or combustion system of this invention is illustrated in Figs; land 2 in assembly relation with a space heater having a motor compartment 20 and a heate'xchange unit 2] extended horizontally from one side 22 ofthe motor compartment. A base or standfor the heater is indicated at 25.

"Suitably arranged'within the motor compartment is'an ignition'unit or coil 23, a motor 26, and a combustion air blower 21 which is operated from the mo'tor'26. The blower 21 has an inlet (not shown) open to the atmosphere, and an outlet (not'shown) open tothe motorcompartment 20. On operatio n of the blower 21, therefore, air is supplied to the compartment 20 under pressure so that the motor compartment constitutes an air pressure chamber for a purpose to appear later. A cam and breaker assembly (not shown) ,'which forms part of the heater ignition system, is carried within a housing 28 and is operated by the blower motor 26.

The burner fuel system includes a fuel-metering unit 29, arranged near the top of the motor compartment 20, and a pump 32 positioned below the fuel-metering unit. The pump inlet 33 is arranged in an upright position within the compartment 20, and is connected by a suitable coupling 34 with the outlet 36 of the fuel-metering unit. The outlet of the pump 32 (not shown) is connected with a fuel line 31 which extends within the burner, designated generally at 39. Fuel from a suitable source, located outside of the compartment 20, is supplied to the fuelmetering unit 29 through a fuel supply line 4 I.

The burner 39 is carried in the side wall 22 of the motor compartment 20, and extends outwardly therefrom into a combustion chamber 43 formed within the heat-exchange unit 2|. The heat-exchange unit 2| is of a generally cylindrical shape, and the burner 39 is arranged centrally thereof. Spaced about the peripheral wall or casing 44 of the combustion chamber 43, and between such wall and the outer shell 46 of the heat exchange unit, is a series of heat-radiating fins 4,1,. the rearward ends 49 of which are spaced from the motor compartment side wall 22 so as to form an annular air manifold 5I between the rearend of the combustion chamber wall 44 and the shell 46. The air manifold 5| is common to all of the air passages formed between adjacent fins 41. A circulating air blower 52 is carried ward end 18 of the inner tube 13, which is held in abutting engagement against the member 11 by a lock screw 19 threadably mounted at the rear end of the outer tube 12 for frictional engagement with the inner tube 13.

. Mounted within the rear end 8I- of-theburner side wall H is a 'metal sleeve insert 82 which is provided at its rear end with an end wall 83 of a ceramic material formed with air openings 84 and an electrode opening 86. Arranged within the sleeve or insert 82, in an outwardly spaced relation with the end wall 83, is an end wall 81,

also composed of a ceramic material, and formed with a circularrow of air passages 88. The forward side of theend wall 91 is formed with a rearwardly extended tapered cavity 90 which terminates in an axial bore 89, with the air passages 88'being arranged about the bore 89 and termiforwardly of the ceramic'end wall 81 and con-- stitute a stop for such end wall. a

The rear end 8| of the burner 39 is positioned within an opening formed in the side wall 22 of on the top side of the shell 46 at a position to provide for the blower outlet 53 being in openfluid communicationwith the air manifold 5I. The inlet 54 of the air circulating blower 52 is open to the atmosphere.

The fins 41 terminate at the forward end wall 56 of the combustion chamber 43 and the shell 46 extends beyond such forward end wall 56 to a forward end wall 51 of the heat-exchange unit 2|. An air pressure equalizing chamber 58 is thus formed by the forward end walls 56 and 51 of the combustion chamber and the heatexchange unit, respectively, and the shell 46. The equalizing chamber 58 has a plurality of outlets 59, open to the atmosphere, and provided in the end wall 51 of the heat-exchange unit.

Spaced outwardly from the side wall 22 of the motor compartment 20 and at a position between the combustion chamber wall 44 and the burner 39 is an upright annular flat ring 6I which is 1 formed with a series of exhaust openings 62 so that an annular exhaust manifold 63, concentrically arranged relative to the air manifold 5|, is defined by the ring BI, side wall 22 and the inner ends of the combustion chamber wall 44 and the burner 39. The exhaust gases from the burner 39 pass outwardly therefrom, as indicated by the arrows 64 inv Fig. 1, centrally of the combustion'chamber 43, and upon striking the combustion chamber end wall 56 are deflected and turned to flow ina reversed direction, as indicated by the arrows 66, for flow through the exhaust ports 62, into the exhaust manifold 63 and outwardly from the exhaust manifold through a pair of oppositely arranged exhaust outlets 61.

'I'heburner 39 (Figs. 3,4 and 5) is formed with a, hollow tubular side wall 1I comprised of a pair of metal tubes 12 and 13 which are maintained in a spaced-concentricrelation by spacer members 14 so as to form an air passage 16 therebetween. The forward end of the outer tube 12 carries an annular insert 11 composed of a ceramic material. This insert constitutes a stop adapted for abutting engagement with the for the motor compartment 20 such that the, rear the. bore 89, formed in the end walls '83 and 81,1

respectively, is an electrode IOI, the rear end I02 of which projects within the motor compartment 20 for direct connection with the ignition coil 23. The front end I03 of the electrode IOI. projects forwardly from the ceramic partition or end wall 81 andterminates in a tapered portion I04 which is located within the spider or bracket 9|.

A ground electrode I06, extended axially of the burner 39, has its rear end I01 extended through the base 93 of the spider member ill for threadable connection with the base member 93 at I08. Mounted on the projected rear end I01 of the ground electrode I06 is a ceramic member I09 of 'a generally cylindrical shape having a cavity III formed in its rear end, and arranged rela--' tive to the electrode I06, such that the rear end I01 of such electrode terminates within the bottom wall H2 of the cavity III. The cavity side wall H3 is of a relatively narrow thickness, to reduce the mass thereof, and with this side wall terminating in a rearwardly and inwardly inclined or tapered surface H4. Mounted on the ground electrode I06 at a position forwardly of the spider base member 93 is a deflector member H6 of a generally pear shape having its small or rear end H1 adjacent to the base member 93 while its large or front end H8 terminates adjacent to the inner metal tube 13 of the burner side wall 1I so as to form with the tube 13 an annular passage H9. The electrode I06 is connected to ground through the spider 9l, tube 13, sleeve 82, spacers 14, tube 12 and the compartment side wall 22.

As shown in Fig. 3, the adjacent ends I04 and I 01 of the electrodes I M and I06, respectively, are relatively spaced both axially and transversely of the burner 39, with the transverse spacing being accomplished by a bend in the electrode 'I'OI, asindicated at I2I. It is thus seen that the apex of the tapered end portion I04 of the electrode IOI is positioned above the top portion I22 of the cavity side wall II3 andrearwardlyof the ceramic I09. Further, it willbe noted that thelegs 92 of the spider 91 are inclined forwardly and inwardly from their endssecured at 94.

The electrodes I and I06 are in alignment longitudinally ofthe burner 39. Also, from a consideration of Fig. 5, it is seen that the spider leg, indicated as 92a, is vertically disposed above the adjacent ends of the electrodes HM and I06, and in turn above the cavity side wall portion I22. The fuel line'37 for the burner 39 is extended through the ceramic end walls 83 and 8I-at a position spaced vertically above the electrode IOI and has its discharge end I26 terminating in the tapered surface 90. The electrodes IOI and I06, the fuel line 31 and spider arm 92a are thus arranged in a substantially common vertical plane. I

i In the operation of the burner the electrode IOI, which'is the hot electrode, is supplied from the coil unit 23 with a high potential heavy current having a capacity in the neighborhood of from fifty to one hundred milliamps so as to effect a high heat arc discharge, indicated at I28 in Fig. 3, between the electrodes MI and I06. By virtue of the arrangement of the ceramic member I09 relative to the adjacent ends of the electrodes I 0| and I06, the arc I 28 is directed to follow a path from the apex of the tapered portion I04 on the electrode iOI, downwardly underand against the cavity side wall portion I22 to the electrode I06. As a result of this travel of the arc discharge I28 the heat developed thereby is localized or concentrated within the cavity I II and in the cavity side wall portion I22, which, as was previously mentioned, is of a relatively low mass.

Air under pressure from the motor compartment 20 is admitted through the openings 84, in the end wall 83, into the equalizing chamber 98 and then through the air passages 88 in the end wall 8'! for discharge about the electrode end I03. Mounted on the electrode end I03 is aiceram ic member I3I, of a pear shape similar to the deflector member I I6, having the large end I32 thereof arranged adjacent to and rear- Wardly of the tapered portion I04 of the electrode IOI The air discharged from the passages 88 is deflected outwardly by the deflector member I3I and the tapered surface II4 on the ceramic member I09 so as to provide for a substantially non turbulent air zone about the adjacent ends of the electrodes IOI and I06.

As a result of this introduction of air through the passages 88, and the cooperative action of the air deflectors or shields I3I and H4, thearc discharge I28 is shielded or protected against being cooled by the flow of the incoming combustion air; It is seen, therefore, that the heat developed by the arc I28 is both localized within the cavity III and conserved against being dissipated by the cooling effectsof the combustion air,.: all for the purpose of obtaining and then utilizing the full effective heat developed by the are for fuel igniting purposes. 7

The fuel enteringthe burner at I26 from the fuel line 31 impinges against-thespider leg 92a and a part thereof is deflected downwardly on to the cavity side wall portion I22. Due to the ceramic composition of the member I09 and the heating of the cavity side wall. portion I22 by the arc discharge I28, some of the fuel falling on the cavity side wall portion I 22 is heated and vaporized, while other parts thereof travel through the side wall portion I 22 by capillary action, into the cavity III. Still other parts of the fuel on the cavity side wall portion I22 may travel directly over thelip of such side wall portion, indicated at I35, for direct contact with the arc discharge I28 travelling about such lip.

It is contemplated that the fuel, deflected onto the member I09, have a mass, or be of an amount, such that it is readily capable of being heated and ignited by the available ignition heat of the arc discharge, for a temperature of the air and fuel in the neighborhood of minus sixty-five degrees Fahrenheit (-65 F.).

That part of the fuel ignited within the cavity III by the arc I28 is violently expelled from the cavity and projected against the large end I32 of the deflection member I3I. This action is aidedby the area of reduced air pressure created between the forward or large end I32 of the member I 3| by the action of the incoming air from the passages 88 sweeping over the small end of the member I3I. This ignited fuel or jeto'f flame from the cavity II I ignites any fuel on the member I3I and is thenswept or picked up by the air passing around the member I3I and carried into the remaining parts of the fuel discharged from the fuel line 31 to ignite such; remaining parts.

Stated otherwise, that part of the fuel initially ignited and projected against the deflector member I3I is reversed in direction and swept toward the deflector IIB so as to function as a pilot flame for the remaining parts of the fuel supplied from the fuel line 31. The resultant ignited air and fuel mixture then travels about the deflecting member IIG for passage outwardly from the burner through its end 99.

As this resultant air and fuel mixture travels through the burner supplementary or secondary air for combustion is progressively intermixed therewith by the provision of a series of openings I5 formed in the inner metal tube 13. Since the air from the passage I6 is under pressure, the air discharged through the openings I5 travels radially of the burner 30, and on mixing with the burning mixture forms radial jets of flame that project inwardly toward the axial center of the burner.

The electrical system for the burner, as shown in Fig. 6, includes a battery IBI, a main line switch I82, a time-delay switch I83, a cut-off switch I84 and a temperature control or rheostat switch I86. The switches I83, I84 and I06 are mechanically connected for concurrent operation by a linkage system, indicated at I81, with the time-delay switch I83 being closed through a trip mechanism (not shown) actuated by the arm 204 of the switch I86. The electrical system also includes a switch 86 providing for either a stand-by or a run opera-tion of the heater.

On starting of heater operation, the switch I88 isactuated to its stand-by position indicated in dotted lines at A, the arm 204 of the temperature control switch I83 is moved to a position. on the rheostat resistance 206 and the main line switch I82 is then closed. A thermostatic switch I9I, connected in parallel with the time-delay switch 7 tion to the heat of the exchange unit 2| and is normally closed when cold. Thus on starting, the circuit for the electrodes I04 and I06, from the battery I8I, comprises the conductor I92, the time-delay switch I83, the cut-off switch I84, and the conductor I93 which is connected to the terminal I94 which in turn is connected with the winding I96 of the ignition coil 23 through the thermostatic switch I90. The coil winding .I96 is connected through conductor I91 with the electrode IOI the electrode I being connected to the ground, in a. manner previously explained, so as to complete the electrode circuit.

The pump 32 is of a solenoid-actuated type and has a winding I98 connected with the terminal I94 through conductor I99. A breaker assembly, indicated generally at 29I, and carried within the housing 28, shown in Figs. land 2,'is interposed between the windings I96 and I98, and the ground. As hereinabove referred to, the breaker assembly 28I is operated by the motor 26 for the combustion air blower 21.

The circuit for the combustion air motor 26 is similar to that of the ignition coil 23 and pump 32 from the'battery to the terminal I94. From the terminal I94 the combustion air motor circuit includes the switch arm 204 of the heat control switch I86, the rheostat resistance 206, conductor 201, a shunt resistance 208, arm 209 and conductor 2lI of the switch I88, and conductor 2I2 which is connected toone side of the motor 26, with this circuit being completed through the motor ground 2I3.

The circuit for the circulating air motor 52 is similarto that of the combustion air motor 26 from the battery I8I through the conductor 201. The motor 52 has one side connected to the conductor 201, through conductor 2I0, while its other side is connected to ground through conductor 2H3, arm 2|4 of the switch I88, conductor 2I2, motor 26 and the ground 2I3. Thus for a standby position of the switch I88 the

motors

26 and 52 are connected in series, and the shunt re-.

sistance 298 is connected in parallel with the motor 52.

As a result the combustion air motor 26 is operated at a nearly normal speed, as determined by the position of the rheostat arm 204, and the circulating air motor 52 operates at a greatly reduced speed, relative to a normal speed therefor, on less than a normal current input to the motor This relative operation of the motor 52 at a reduced speed, and of the motor 26 at approximately a normal'speed for a current input normally required for the motor 26 alone, is highly desirable for a stand-by operation of the heater in order to conserve the battery 'I8I. normal operation of the heater has been attained, the circuits for the pump32, air circulating motor 62, and combustion air motor 26 are closed by the thermostat switch I9I so that any later opening of the time-delay switch I83 is rendered ineffective in these circuits. With normal operation of the heater, or on the establishment of combustion, the circuit of the coil 23 is opened by the thermostatic switch I90. If, for any reason, heater operation fails to take place within the time limit predetermined by the time-delay After a v switch I83, the complete circultis opened by the time-delay switch whereby current is shut on to the coil 23, pump 32, and motors 26. and 52.

On a movement of the-switch I88 to its run position, indicated in dotted lines at B in Fig. 6, the circuit of the circulating air motor 52 from the conductor 2I5 includes the arm 2.2I, of the switch I88, and the conductor 222 which is connected to the ground 2I3. For this run position of switch I88, the shunt resistance 208 is cutout and the circuit of the combustion motor ZB-from the conductor 201 includes the conductors 2|:0 and 224, the arm 226 and conductor 2 ofthe switch I88, conductor 2I2 and the ground 2I3.

It is seen, therefore, that for a run operation of the heater, the

motors

26 and 52 are connected in parallel and operate at normal speeds as determined by the position of the rheostat arm 204 relative to theresistance 206, and with this operation taking place with an increased current consumption for

the'motors

26 and 52, relative to the motor current required .for stand-by operation. U

By virtue of this system it will be noted that the supply of combustion air to the burner 39 is in-: creased concurrently with a decrease in the resistance 209, as determined by the rheostat arm 24, to in turn providefor an increase in the heat output of the heater. This increased heat output is accomplished by virtue of themetering unit 29 being operable in response to the air pressure within the motor compartment 20 to vary the supply of fuel to the fuel line 31.

From a consideration of the above description, it is seen that the invention provides an improved system and method for igniting fuel in a burner, which is positive and efficient in operation to accomplish such ignition for varying types of fuel, and with such fuel, aswell as the combustion air being supplied thereto, being capable of ignition at temperatures in the neighborhood of minus sixty-five degrees Fahrenheit (65 F.). Although the invention has been described relative to operation from a battery, which can be of 6, 12, 24 or 32 volt capacity, it is to be understood that it can'be' used with either A. C. or D. 'C. at any voltage above 6 volts and including volts. Also, where ample electrical energy is available the normal sup ly of fuel to the burner can be directed at one time into the burner ignition zone.

Although the invention has been described with respect to a preferred embodiment thereof, it is to be understood that it is not to be so limited since changes can be made therein which are within the full intended scope of this invention, as defined by the appended claims.

We claim:

1. In a liquid fuel burner the combination with means forming an elongated combustion chamber, means for supplying liquid fuel under pres sure to said combustion chamber, and means for supplying combustion air under pressure to said combustion chamber, independently of said fuel supply, for forward flow longitudinally therethrough, of an ignition system including front and rear elongated electrodes arranged in adjacent end to end relation longitudinally within said combustion chamber, means providing for an arc discharge between the adjacent ends of said electrodes, said adjacent ends of the electrodes being longitudinally and laterally spaced from each other, a ceramic member surrounding the front one of said electrodes having a cavity therein, said front electrode having the arc end thereof terminating in the bottom wall of said cavity so that the arc discharge is directed to travel within said cavity and along a portion of the cavity side wall prior to its passage to the arc end of the rear electrode, means for directing only a part of the liquid fuel from said fuel supply means to said ceramic member and the cavity therein for ignition by the arc discharge, and means on the arc end of said rear electrode for deflecting the flow of combustion air against direct entrance into said cavity so that the combustion air about said cavity is in a quiescent state, with said portion of the fuel, on ignition thereof, being dispersed away from said cavity into said flow of combustion air to initiate ignition of the other portions of fuel supplied to said combustion chamber.

2. In a liquid fuel burner the combination with means forming an elongated combustion chamber, means for supplying liquid fuel under pressure to said combustion chamber, and means for supplying combustion air under pressure, independently of said fuel supply, for flow longitudinally through said combustion chamber, of an ignition system comprising a pair of electrodes extended in adjacent end to end relation longitudinally within said combustion chamber, means providing for an arc discharge between the adjacent ends of said electrodes, deflectors, one mounted on the adjacent end of each of said electrodes for shielding said are against the forward flow of combustion air so as to reduce any cooling effect on said are by said combustion air, one of said deflectors having a cavity therein with the arc end of the carrying electrode terminating in the bottom wall of the said cavity so that the arc discharge is directed to travel Within said cavity, means for directing a portion of the liquid fuel from said fuel supply means to said arc in an amount commensurate with the heating capacity of the are such that said portion of the fuel is incapable of cooling the arc to a temperature which would be insufficient to ignite said portion of the liquid fuel directed thereto, with said portion of the fuel, on ignition thereof, being dispersed into the flow of combustion air about said shielding means to initiate ignition of remaining portions of the liquid fuel supplied to said combustion chamber.

3. In a liquid fuel burner the combination with means forming an elongated combustion chamber, means for supplying combustion air under pressure for flow through said combustion chamber from the rear end thereof, and means for supplying liquid fuel under pressure to said combustion chamber, independently of said air supply, of an ignition system comprising a front elongated electrode and a rear elongated electrode arranged in adjacent end to end relation longitudinally of said combustion chamber, means providing for an arc discharge between the adjacent ends of said electrodes, said adjacent ends of the electrodes being longitudinally and laterally spaced from each other, a ceramic member mounted on the rear end of the front electrode having a cavity in the rear face thereof, with the rear end of said front electrode terminating in the bottom wall of said cavity so that the arc discharge is directed to travel within said cavity and along a portion of the side wall thereof to the front end of said rear electrode, a second ceramic member mounted on the rear end of said front electrode at a position to shield said are from the direct flow of combustion air thereon, and means for directing only a portion of the liquid fuel from said fuel supply means to said side Wall portion of the cavity for ignition, with said portion of the fuel, on ignition thereof, being thrown rearwardly against said second ceramic member for dispersion into the forward flow of combustion air to initiate ignition of the remaining portions of fuel supplied to said combustion chamber.

HARRY B. HOLTHOUSE, SR. HARRY B. HOLTHO USE, JR.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 893,955 Van Woert July 21, 1908 980,801 Kraus a Jan. 3, 1910 963,711 Jeiferey July 5, 1910 1,905,957 Anderson Apr. 25, 1933 2,119,830 Powers et a1. June 7, 1938 2,423,410 Simmons July 1, 1947