US2916088A

US2916088A - Fuel burner control apparatus

Info

Publication number: US2916088A
Authority: US
Publication date: 1959-12-08
Anticipated expiration: 1976-12-08

Description

Dec. 8, 1959 J BEAL ET AL 2,916,088

FUEL BURNER CONTROL APPARATUS Filed Sept. 13, 1956 INVENTORJI Jmmeslflqal and BY John 6min w/w mmmw United tates Patent 2 91'6,088 FUEL BURNER CONTROL APPARATUS James F. Beal, Greensburg, and John Gogniat, In, Slickville, Pa., assignors to Robertshaw-Fulton Controls Company, Richmond, Va., a corporation of Delaware Application September 1'3, 1956, Serial No. 60?,665

4 Claims. (Cl. 158-115 This invention relates to fluid fuel burning appliances and more particularly to an ignition and control system ,for a fluid fuel burner.

Current fluid fuel burners such as those used in domestic cooking ranges generally employ a flash tube for igniting the main burner or a single constantly burning pilot burner adjacent the main burner. One of the main disadvantages in such an ignition means is that a delay in ignition occurs after the fuel to the main burner is turned on. In the flash tube system, the fuel must pass through the tube to the pilot burner, and a flame must return through the tube before ignition can occur. Although the delay is not as great when the pilot burner is positioned immediately adjacent the main burner, there is still a substantial lapse in time before ignition occurs.

A major disadvantage of both the flash tube and adjacent pilot burner ignition system is the fact that the constantly burning pilot flame used in both systems must be as small as possible to conserve fuel when the range is not in operation. In a system wherein the pilot burner is positioned adjacent the main burner flame of sufficient size to effect proper andimmediate ignition has been found to be unsatisfactory from the standpoint of operating cost.

Another objectionable disadvantage of an ignition system utilizing a constant burning pilot burner is the appreciable and unnecessary heat generation during the standby periods. Since the flame is of necessity fairly large to effect proper ignition of the burner, it will be apparent that a substantial amount of heat will be generated during the standby periods.

In the older forms of cooking ranges where the supply of fuel to the top burners was controlled manually by the operator, the disadvantages discussed above in connection with the pilot burner ignition systems did not create a sufficient hazard to warrant their improvement since the burner was usually ignited at the beginning of the cooking operation and remained ignited until the cooking operation Was completed. However, in the most modern cooking ranges where cooking operations are thermostatically controlled on the top burners, a form of control is maintained by periodically supplying fuel to the burners. With such thermostatic control, it will be apparent that a burner will be extinguished and ignited a number of times during the cooking operation, and the delay inignition can be extremely hazardous.

It is an object of this invention to effect immediate ignition of a burner upon supply of fuel thereto.

Another object of the invention is to effect substantially instantaneous ignition of the main burner upon supplying fuel thereto while maintaining a minimum pilot flame when the burner is not in use.

Another object of the invention is to effect. a cooking operation on a burner at a desired temperature and to immediately ignite the burner upon a decrease in the temperaturebelow that which is desired.

Another object of the invention is to supply fuel to a pilot burner at a low rate when 'the main burner is not 2,916,088 Patented Dec. 8, 1959 in operation and at an increased rate when fuel is supplied to the main burner.

Another object of the invention is to produce an ignition flame in close proximity to the ports of a main burner when fuel is supplied to the main burner.

Another object of the invention is to impinge a pilot flame on a flame retainer in close proximity to the ports of a main burner when fuel is supplied to the main burner.

Another object of the invention is to increase the flow of secondary air relative to a main burner and to establish a convection flow of fuel within the main burner.

In one embodiment of the invention, a control device, including a shut-off valve and a thermostatically actuated valve, is provided for controlling the supply of fuel to a main burner from a source of fluid fuel. A constantly burning pilot burner is positioned adjacent the main burner and connected directly to the source. An ignition burner is also positioned adjacent the main burner and pilot burner and connected to the control device downstream of the shut-off valve whereby fuel is supplied thereto when the shut-off valve is moved to an on position. A target or flame retainer is positioned adjacent the main burner ports, and the ignition burner is arranged whereby the fuel emitted therefrom is ignited by the pilot burner to impinge a flame on the target.

Other objects and advantages will become apparent from the following description taken in connection with the accompanying drawings wherein:

Fig. 1 is a schematic showing of a burner control apparatus embodying this invention;

Fig. 2 is a schematic showing of another embodiment of the invention; and

Fig. 3 is a perspective view of a portion of the apparatus shown in Figs. 1 and 2.

Referrnig more particularly to Fig. l, the control apparatus includes a control device 10 for controlling operation of a fluid fuel burner 12. The burner 12 is of conventional form having an annular chamber 14 therein for fuel and a plurality of radially disposed ports 16 adjacent the upper end thereof for emitting fuel. The burner 12 may be supported in any suitable manner and includes a plurality of supporting members 17 associated therewith for supporting a cooking vessel 18 (Fig. 2) over the burner.

The control device 10 is generally of conventional form and is adapted to control the supply of fuel to the main burner 12. More particularly, the control device 10 includes a casing 19 provided with an inlet 20 which is connected by a suitable pipe fitting to a source of fluid fuel or manifold 22, and an outlet 24 which is connected by a pipe 26 to the burner 12.

The casing 19 is provided with a tapered valve seat 28 in which a hollow plug valve member 30 is seated and adapted to be rotated by means of a manually operable dial 32. The plug valve member 30 is adapted to control the flow of fuel between the inlet 20 and outlet 24 and is provided with an arcuate recess 34 in the tapered surface thereof and an opening 36 through the Wall there of at one end of said recess. In the position shown in Fig. 1, the tapered surface of the valve member 30 faces the inlet 20 and prevents flow of fuel to the hollow interior of the plug valve member 30 and the outlet 24. However, upon clockwise rotation of the dial 32, the recess 34 will be moved into communication with the inlet 20 and remain in communication through a substantial range of movement of the cock 30 thereby permitting flow of fuel into the hollow interior of the shutoff cock and out of the open bottom thereof to the outlet 24.

- Thermostatic valve means are also provided for controlling the flow of fluid between the inlet 20 and outlet 24. To this end, the casing 19 is provided with a valve seat 38 downstream of the valve member Ztl for cooperation with an axially movable disc-shaped valve member 40 which is carried on a medial portion of an axially movable valve stem 4'2. A spring 44 is mounted in com.- pression between the valve member 4i) and the casing 19 and serves to bias the valve member an away from the seat 38.

A thermostatic mechanism is carried by the end wall of the casing 19 for actuating the valve member 45 between positions relative to the seat 38 and includes an expansible power element as fixed to the said end wall of the casing. The power element 46 is connected by means of a capillary tube as to a temperature sensing element 55) which is supported centrally of the burner 12 for engagement with a cooking vessel by a cylindrical telescopic shield 52, which in turn may be supported by any suitable means.

The power element 46, capilla-y tube 8 and sensing element St define a closed system filled with a temperature responsive fluid which upon variations of the temperature sensed by the element St will serve to expand and contract the power element 45 in a manner well known to those skilled in the art.

The valve stem 42 is threaded within a cup-shaped member 54 carried by the power element 45 to be moved axially upon expansion and contraction of the power element 46 to position the valve member dll relative to the seat 38. To adjust the temperature at which the valve member 40 will engage the seat 38, an operating member 56 extends through the valve member 349 and is rotatable therewith. The end of the member 56 is connected to the valve stem 42 by a torque transmitting connection 58 and is operative upon rotation to screw the stem 42. into or out of the member 54 to adiust the position of the valve member 4% relative to the seat 38.

The apparatus thus far described operates in a manner well known to those skilled in the art. Rotation of the dial 32 will serve to rotate the valve member 3@ from the position shown into a range of movement wherein the recess 34 is in communication with the inlet 2%. This range of movement of the valve member 3d enables the operating member 56 to be rotated through a plurality of temperature settings.

Means is provided for igniting the burner 12 upon supply of fuel thereto by rotation of the valve member 30. To this end, a generally U-shaped bracket 61) is positioned adjacent the burner 12 and defines a medial portion 62 having a leg 64 extending therefrom in close proximity and in parallel to the side of the burner 12, and another outwardly bent leg 66 spaced from the leg 64. A constantly burning pilot burner 68 is supported on the medial portion 62 by means of a suitable fitting 76 and is connected by a conduit or pipe 72. directly to the manifold 22. A filter 74- and a manually adjustable valve 76 are connected in the conduit '72, the valve 76 being manually operable to adjust the flow of fuel from the manifold 22 and thus the size of the flame at the pilot burner 68.

An ignition burner 78 having a non-aerated jet pilot orifice 79 is supported on the leg 66 by means of a fitting 8t) and is connected by a conduit or pipe 82 to an outlet passage 83 in the casing which communicates with the downstream side of the valve member 3% and hollow interior thereof. A flame adjustment valve 84 and filter 86 are also disposed within the conduit 82;.

The ignition burner 78 is preferably positioned by means of the leg 66 to emit a directed stream of fuel over the tip of the flame at the burner 68 toward one side of the burner 12 and toward a point slightly below the ports 16. In this manner, the flame isg from the constantly burning pilot burner ignites the fuel emitted from the ignition burner 7 S which in turn is operative to ignite fuel emitted from the ports 15.

Means are provided for retaining the flame at the ignition burner 78 immediately adjacent the main burner ports 16. To this end, a plate or target 88 has one end attached to the extending end of the leg 64 with the upper edge thereof in alignment with the bottom edge of the port 16. With the target 83 positioned in this manner, the flame from the ignition burner 78 is impinged on the upper edge of the target and directed upwardly as indicated on the drawing into the path of fuel emitted from the port 16. Thus, the target 8% retains the ignition flame in close proximity to the main burner ports 16. A hood 94) is attached to the legs 64, 66 and substantially encloses the bracket 60 to shield the burners 78, 68 from outage due to drafts or spillage.

In operation of the embodiment shown in Figs. 1 and 3, the valve 76 is adjusted to provide a very small flame at the pilot burner 68 and the valve 84 is adjusted to supply a larger amount of fuel to the burner 78 whereby a flame as indicated in dotted lines will be produced when fuel is supplied to the outlet With the parts in the position shown in the drawing, no fuel will be supplied to the main burner 12. or the ignition burner 78 since the shut-off cock 3%) is in the ofF position. Should the shut-off cock 3t be rotated clockwise until the recess 34 is aligned with the inlet 2%, fuel will flow from the manifold 22 through inlet 2 into the hollow interior of the valve member 30 and out of the bottom thereof to the valve seat 38. Since the outlet 83 communicates directly with the downstream side of the valve member 3t), fuel will immediately be supplied to the ignition burner '73 upon the aforesaid rotation of the valve member i Also, since the main burner 12 has not yet been i ted, the sensing element 5% will be cold and the valve n niber 4i will be out of engagement with the seat 38. Therefore, fuel will also be supplied to the chamber 14- in the main burner 12 by means of the conduit 26.

The fuel emitted from the burner 73 will reach the constantly burning pilot burner 68 and be ignited thereby to produce a flame as indicated in dotted lines in Fig. 1. Fuel emitted from the ports 16 adjacent the flame produced at the ignition burner 78 will be ignited and the apparatus will be conditioned to perform a cooking operation.

When the sensing element 5% is heated by the cooking vessel to a temperature selected by the dial 32, the power element 46 will expand sufliciently to move the valve member 40 into engagement with the seat 38 and terminate the supply of fuel to the main burner 12. If the temperature of the sensing element 50 should fall below the set temperature, the valve member 4-!) will be moved out of engagement with the seat 38 to again supply fuel to the main burner. However, during this cycling of the valve member 40 into and out of engagement with the seat 33 in response to a temperature condition sensed by the element 59, the ignition burner 78 will remain ignited unless the shut-elf valve 30 is rotated to the Off position. Thus, the flame indicated in dotted lines at the ignition burner will exist during the entire cooking operation.

It will be apparent from the foregoing that ignition of the main burner will occur substantially instantaneously upon supply of fuel thereto. Thus, ignition at the main burner is eflected without the hazardous delay present in current ignition systems. It will also be apparent that the ignition system herein described will not add to the cost of operation of the appliance in which it is used since the constantly burning pilotburner is only used to effect ignition of the ignition burner and need be only supplied with suflicient fuel to maintain a minimum flame.

Since the target 88 retains the flame from the ignition burner '78 and directs the flame upwardly into the path of fuel emitted from the main burner 12, it will be apparent that the ignition flame cannot create a back pressure at the main burner ports 16 or obstruct or retard the passage of fuel therefrom. Accordingly, the maximum efficiency of the system is maintained.

It has also been found that the location of the target 88 in close proximity to the side of the burner 12 establishes a hot surface which promotes the flow of secondary air between the target 88 and the side of the main burner 12. Also, the target 88, being located close to, but not against, the main burner causes some heating of one side of the burner 12 and sets up a natural convection flow of fuel within the chamber 14 to the ports 16 adjacent the target 88. The last said feature is very important during opening and closing of the valve member 40 during the cooking operation in that quantities of fuel are directed to the ports 16 adjacent the target 88 where ignition occurs instantaneously.

Referring to Fig. 2, another embodiment of the invention is illustrated wherein the ignition burner 78 serves as both a constant burning pilot burner and an ignition burner. More particularly, the ignition burner 78 is supported on the leg 66 as shown in Fig. 1 but is connected directly to the manifold 22 by means of a conduit 92. Similarly to Fig. l, a filter 94 and manually operable valve 96 are disposed in the conduit 92. With this arrangement, a constant supply of fuel is maintained to the burner 78 and the flame indicated in solid lines will be maintained as adjusted by the valve 96.

A second conduit 98 connects the outlet 83 with the conduit 92 by means of a T-fitting 100 for supplying additional fuel to the burner 78 upon rotation of the valve member 30 to the On position. A filter 102 and manually operable flow adjustment valve 104 are also disposed in the conduit 98.

In operation of the embodiment shown in Fig. 2, the flame indicated in solid lines will exist at the burner 78 when the shut-01f cock 30 is in the Off position. However, when the shut-off valve 30 is rotated to the On position, fuel will instantly be supplied to the conduit 98 and thus provide additional fuel for the conduit 92 and the burner 78. This substantial increase in supply of fuel to the burner 78 will immediately elfect an increase in the size of the flame equivalent to that indicated in dotted lines. Such flame impinges on the target 88 similarly to the flame produced at the burner 78 in the embodiment of Fig. 1. Accordingly, the ignition burner 78 serves both as a constantly burning pilot burner and ignition burner eliminating the need for the burner 68 illustrated in Fig. 1.

While two embodiments of the invention have been herein shown and described, it will be apparent to those skilled in the art that many changes in the construction and arrangement of parts may be made without departing from the scope of the invention as defined in the appended claims.

It is claimed and desired to secure by Letters Patent:

1. In a fluid fuel burning apparatus, the combination comprising an annular fluid fuel burner having a plurality of radially spaced ports for emitting fuel, a generally U-shaped bracket positioned at one side of said burner having one leg, terminating adjacent said ports and the other leg thereof spaced therefrom, an ignition burner secured to said other leg including means to direct fuel toward said one leg to produce a flame thereon, and a pilot burner supported on the medial portion of said bracket intermediate said legs for igniting fuel emitted from said ignition burner.

2. A fluid fuel burning apparatus as claimed in claim 1 wherein said bracket is provided with a hood substantially enclosing said ignition and pilot burners.

3. A fluid fuel burner apparatus comprising in combination a main fluid fuel burner having a plurality of ports therein for emitting fuel, conduit means for supplying fuel from the source to said burner, valve means in said conduit means including a valve seat and a valve member movable between open and closed positions relative to said seat for controlling the flow of fuel to said burner, a generally U-shaped bracket positioned adjacent said burner and having one leg thereof positioned in close proximity to said ports and the other leg thereof spaced from said one leg by the medial portion thereof, a pilot burner supported on said medial portion, conduit means for supplying fuel from the source directly to the pilot burner, an ignition burner supported on the other leg including means for directing fuel towards said one leg over said pilot burner to produce a flame thereon, and conduit means for supplying fuel from the downstream side of said valve means to said ignition burner whereby fuel is supplied to said ignition burner when said valve member is in said open position and an ignition flame is produced on said one leg in close proximity to said ports.

4. In a fluid fuel burning apparatus, the combination comprising an annular fluid fuel burner having a plurality of radially spaced ports for emitting fuel, a generally U-shaped bracket positioned at one side of said burner having one leg terminating adjacent said ports and the other leg thereof spaced therefrom, means secured to said other leg to direct fuel toward said one leg to produce a flame thereon, and a pilot burner supported on the medial portion of said bracket intermediate the legs for igniting fuel emitted from said fuel directing means.

References Cited in the file of this patent UNITED STATES PATENTS 947,914 Junkers Feb. 1, 1910 951,724 Cole Mar. 8, 1910 1,932,740 Kerr Oct. 31, 1933 2,025,413 Hegwein et a1 Dec. 24, 1935 2,155,122 Fox Apr. 18, 1939 2,180,789 Browning Nov. 21, 1939 FOREIGN PATENTS 1,049,750 France Aug. 19, 1953 494,216 Great Britain Oct. 21, 1938