US2755849A - Pot-type burner and ignition system therefor - Google Patents

Description

J y 1956 B. c. WATTS, JR., ETAL POT-TYPE BURNER AND IGNITION SYSTEM THEREFOR 3 Sheets-Sheet 1 Filed Oct. 15, 1952 w 4 w 5 mm T ,5 3 N55 v! ET E VT/ N N L IAL R W m a. N M 4 m saw R U m R A .Hl Hm n Ema H A R x IJIR |H.||l1( NW. VIII 'I l NM July 24, 1956 B- c. WATTS, JR., ETAL 2,755,849

POT-TYPE BURNER AND IGNITION SYSTEM THEREFOR I 3 Sheets-Sheet 2 R m INVENTORS \3 N BLAINE 0. WA rrs, JR. #3, ARTHURBQ} r05 WILLIAMS N a 7 7 w 5 l fiwmmd ATTORNEYS y 24, 1956 a c. WATTS, JR., ET AL 2,755,849

POT-TYPE BURNER AND IGNITION SYSTEM THEREFOR Filed Oct. 15, 1952 3 Sheets-Sheet 3 ATTORNEYS United States Patent Ofice POT-TYPE BURNER AND IGNITION SYSTEM THEREFOR Blaine Clyde Watts, Jr., and Arthur Clyde Williams, Petaluma, Calif., assignors to Kresky Mfg. Co. Inc., Petaiuma, Califi, a corporation of California Application October 15, 1952, Serial No. 314,772

2 Claims. (Cl. 8-91) This invention relates to new and useful improvements in electric igniters for use in conjunction with oil burners of the type set forth in Miller Patent No. 2,391,585.

Oil burners of the type with which this invention is concerned comprise a burner having an oil reservoir in the bottom and a sump below the reservoir into which an oil line from an oil tank discharges. The sides of the burner are perforate and air under pressure is forced through the holes. After the oil is ignited, combustion is maintained by mixing of the oil vapor and air. The present invention relates to means for initiating combustion by an electric ignition coil.

The present invention employs an offset, independent ignition chamber containing a wick up which oil rises by capillary action to be ignited by the electric coil located adjacent and spaced slightly from the top of the wick. A portion of the air under pressure which is supplied to the burner is caused to flow down past the wick and out into the bottom of the burner combustion chamber with which the ignition chamber communicates.

The wick is preferably formed of porous, non-heat conducting, heat resistant dielectric material, such as light weight cast fire brick or asbestor. The wick desirably has both external and internal capillary action so that the oil rises both inside and outside of the wick to the vicinity of the electric coil at the top of the wick. The electric coil is not in contact with the wick but is spaced slightly therefrom to deter accumulation of carbonaceous material.

Another feature of the invention is the location of the ignition chamber in the stream of air supplied by the blower which furnished air to the burner. Around the burner is a sheet metal casing 01' air box. Air is blown inside said air box and then is forced through the perforations in the burner walls to the interior of the burner. One of the features of this invention is the location of the ignition chamber offset from the burner inside the air box; thereby making possible the path of air flow which has heretofore been described.

Another feature of the arrangement is that the air from the burner passes over the transformer which furnishes low voltage, high amperage current for the ignition coil, thereby cooling the transformer.

The igniter which is a part of this invention is ar ranged so that air is forced past the top of the wick on each side of the hot coil and down toward the bottom of the burner to project the flame outwardly and fan- -wise into the burner at the base of the end side walls of the burner. The location at which ignition occurs most readily is at the juncture of the side walls and the base, and from this zone the flame will spread rapidly the entire length of the burner.

A radiant heat switch is installed in the air box in such position as to insure long life of the switch. This switch serves to de-energize the ignition coil after the burner temperature is elevated to support combustion without independent ignition.

The ignition chamber is positioned offset from the Batented July 24, 1956 normal combustion area of the burner in a separate chamber which is partially enclosed from the burner chamber. This maintains the ignition chamber cooler than would be the case if the wick and coil were located within the burner chamber and enhances the life, of the wick and coil.

Other objects of the present invention will become apparent upon reading the following specification and referring to the accompanying drawings in which similar characters of reference represent corresponding parts in each of the several views.

In the drawings:

Fig. l is a top plan of the burner having the ignition device incorporated therein. 0

Fig. 2 is a longitudinal, vertical section taken substantially along the line 2--2 of Fig. -1

Fig. 3 is a transverse vertical section taken substantially along the line 33 of Fig. 2.

Fig. 4 is an enlarged fragmentary section of the ignition chamber taken substantially along the line 4.4 of Fig. 3.

Fig. 5 is a perspective view of the wick, ignition, coil, electrodes and supporting structure.

Fig. 6 is a wiring diagram of a portion of the electrical circuit of the device.

Fig. 7 is a vertical section taken sbstantially along the line 77 of Fig. 2.

The instant invention is adapted for installation in a burner such as that described in Miller Patent No. 2,391,585. Such a burner employs a lower casting 21 and an upper casting 22 which telescopically fits within the lower casting. The lower casting 21 comprises a rectangular, elongated open top box, the interior of which is recessed to provide a reservoir '23 in the bottom in communication with a sump 24 and has horizontal shoulders 26 extending along the side edges above the reservoir 23. The upper casting 22 is open at the top and bottom, the lower edge of the skirt 27 resting upon the horizontal shoulders 26 of the casting 2-1. The sides 28 of the skirt 27 are perforated with a large number of small diameter holes 29. In one form of such burner the sides 25% and skirt 27 flare outwardly at an angle of approximately 74 degrees, as illustrated herein (see Fig. 1), although the skirt 27 may be formed substantially vertical.

Around the burner is an air box 31 which is bolted to the top outwardly extending flange 32 of the upper casting 22. The air box 31 extends beyond the upper and lower castings in an extension 33 beyond one end of the burner and communicates through a transformer box 34 with a blower 36 driven by motor 37. Air is forced by blower 36 through the transformer box 34 into the air box extension 33 and thence flows around the sides of the burner and through the perforations 29 in the skirt 27 of the upper casting 22 and into the combustion chamber 38 of the burner. Oil is supplied to the burner by means of pipe 39 which leads into the sump 24 at the bottom of the burner.

In the end of the burner adjacent extension 33 is an off-set ignition chamber 41 which is formed as an integral extension of the lower casting 21. The top of said ignition chamber is closed off by cover 42. It will. be observed, particularly with reference to Figs. 2 and 4, that a lip 43 flares outward from the upper edge of' the end of the ignition chamber wall 44 and that an holes 46 are drilled in the wall 44 inside the lip 43 so that air is directed by said lip through the holes 46 into the ignition chamber 41. The end wa'll of the top casting 22 is cut away to form port 47 which provides communication between the ignition chamber 41 and the combustion chamber 38.

Within the ignition chamber 41 issuspended awick 5.1

which rests on the bottom 52 of the ignition chamber which is at the same level as the bottom 53 of the burner chamber 38. The wickSl is preferably formed of a porousmat'erial such as fire brick or similar suitable refractory material. The desirable characteristics of the wick are that it be porous, subject to internal and external capillary action, non-heat-conducting, heat-resistant and dielectric. The wick 51 is broader at the bottom than at the top and in end elevation resembles a truncated triangle. The wick 51 is supported in position by wire 54 which is cemented in a hole 56 in the wick and is bent upward and then backward, the top stretch 57 of the wire being retained ina ceramic casting 58 which is carried by the cover 42 of the ignition chamber.

Immediately above the top of wick 51 and spacedabout inch therefrom is' an ignition coil wire 59. The ends of coil 59 are fixed to the lower ends of electric terminals, 61 and 62 formed'of flat'stock, the horizontal stretches 63 of which are imbedded in casting 58 and projects forwardly from the ignition chamber for attachment to lead wires 64, the opposite ends 66 being bent downwardly, 'the lower ends of the downwardly bent portion being attached to the ends of the'ignition coil 59.

A radiant heat switch 71 is installed on the under side of the cover 72 of the extension 33 of air box 31. The ignition coil transformer 73 is installed in transformer box 34 through which air from the blower 36 travels in its passage toward air box 31. Thus, the transformer 73 and coil 59 are cooled by the passage of air.

Fig. 6 shows a representative wiring diagram for the ignition system. A thermostatic room temperature control switch (not shown) operating oif of transformer 76 actuates a relay 77 which closes switch 78 when the room temperature falls below a specified temperature and opens switch 78 when the room temperature exceeds a specified temperature. Closing of switch '78 closes a circuit to .thermoswitch 71. When the temperature in the air box 31, which is directly proportional to the temperature above the burner, is below 200 the switch arm 79 makes electrical contact with the cold contact 81. This completes a circuit through the primary coil of ignition transformer 73 which in turn induces a high amperage, low 'voltage current through the igniter coil 59 and ignites the oil in the wick 51. When the temperature in the air box exceeds 200 the temperature above the burner is sufficient to support combustion and energization of the igniter coil 59 is unnecessary. Thus the arm 79 of thermoswitch' 71 makes electrical contact with the hot contact 82 which breaks the circuit through the igniter transformer 73. The blower motor 37 is energized so long as switch 78 is closed.

In operation, at the commencement of a cycle of operation of the burner by the closing of a thermostatic switch or any other substitute switch, a valve in the oil line 39 is opened and oil flows through pipe 39 into sump 26 and rises into reservoir 23 on the bottom of the lower casting 21 of the burner. A portion of the oil flows into the ignition chamber 41 which is at the same level as ,the burner chamber 38 and wets the bottom of wick 51. The oil rises to the top of wick 51 and is ignited by coil 59 which is energized by reason of switch 78 being closed and arm 79 of switch 71 contacting cold contact 81, the latter situation existing by reason of the temperature of switch 71 being below 200 F. Meanwhile air has been forced into the air .box 31 from blower 36 through transformer box 34 and extension 33. The major portion of the air is forced through perforations 29 in the skirt 27 :in top casting 22, but a minor portion is forced through air holes 46 in the top of the ignition chamber 41 thence downwardly through the chamber 41 past the top of -wick 51 and thence outwardly into the burner chamber 41 through port 47. The flame which is thus created by wick 51 is forced out into the burner chamber 41 and ignites the oil in the reservoir 23. The oil in the reservoir is readily ignited at the juncture of the ignition chamber 4 l and the burner bottom and spreads out along the entire burner.

When the temperature above the burner and on the under side of the air box cover 72 exceeds a predetermined temperature of, for example, 200 F., switch arm 79 breaks contact with cold contact 81 and makes contact with hot contact 82. This interrupts current through ignition transformer 73 and hence igniter coil 59 is inoperative. At the temperature then existing in the burner, combustion continues without independent ignition.

When the room temperature conditions are such that switch 78 is opened, blower motor 37 continues to operate so long as the thermoswitch 71 temperature is above 200. This insures complete combustion of all the oil remaining in the burner. After the temperature has dropped below 200, which occurs when the oil in the burner is substantially exhausted, then the blower motor 37 is de-energized.

We claim:

1. In combination, an oil burner body member having perforate side walls, an air box around the sides of said body member, an air blower, a transformer box between said blower and said air box, said blower, transformer box, and air box being in fluid communication, said air box being positioned so that air forced therein passes through the perforations in said side walls into said body member to support combustion within said body member, means for supplying oil to said body member, a transformer in said transformer box and positioned to be cooled by air passing through said transformer box from said blower, means forming an offset igniter chamber communicating with said body member and located inside said air box, a wall of said igniter chamber being apertured adjacent the top thereof and in iluid communication with said air box, a wick in said igniter chamber, an igniter coil in said igniter chamber above said wick, said body member being apertured adjacent the bottom of said igniter member to establish communication between said igniter chamber and said body member, said igniter coil being electrically connected to said transformer to be energized by said transformer.

2. The combination comprising a burner member in which oil and air are mixed for combustion having a casting forming an oil reservoir portion in the bottom thereof into which oil flows, said oil reservoir portion being elongate rectangular in plan, and having a flat bottom disposed in an horizontal plane, the point of oil ingress into said reservoir portion being located substantially centrally of said rectangular reservoir portion whereby oil entering the said ingress point flows outwardly in a thin film toward opposite ends of said rectangular reservoir portion, said casting including an integral portion offset at one end thereof defining an igniter chamber, the bottom of said igniter chamber being disposed ,coplanar and in substantially unobstructed oil film flow communication with the bottom of said reservoir, a wick supported in said igniter chamber with its bottom end in contact with the bottom of said igniter chamber and adapted to be in capillary flow communication with said oil film covering the bottom of said igniter chamber, and an electric igniter coil opcratively associated with said wick for igniting oil saturated by said wick.

References Cited in the file of this patent UNITED STATES PATENTS 2,093,312 De Lancey Sept. 14, 1937 2,438,823 Resek et al Mar. 30, 1948 2,553,975 Little May 22, 1951 2,640,648 Judson June 2, 1953 2,646,111 Long July 21, 1953 2,685,917 Perry Aug. 10, 1954 w I, v FOREIGN PATENTS I 477,076" Canada"' Sept:18,' 951

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