US3574501A

US3574501A - Electric igniter

Info

Publication number: US3574501A
Application number: US798743A
Authority: US
Inventors: Richard K Mitts
Original assignee: Robertshaw Controls Co
Current assignee: Robertshaw Controls Co
Priority date: 1969-02-12
Filing date: 1969-02-12
Publication date: 1971-04-13
Anticipated expiration: 1988-04-13

Abstract

An electric ignition system for burners utilizing an igniter having a source of high intensity light and a reflector for focusing the light at a point within igniting proximity of the burner to provide a point of high temperature for ignition of fuel emanating therefrom.

Description

0 United States Patent [1113,574,501

[72] Inventor Richard K. Mitts [56] References Cited Fullerton, Cahf- UNITED STATES PATENTS [21] P 7987 2,364,730 12/1944 Leskin 219/347x [22] Filed Feb. 12, 1969 3,427,118 2/l969 Andress et al. 431/258 [45] Paemed 1971 3 434 788 3/1969 Wright 431/66 [73] Assignee Robertshaw Controls Compan v Richmond, Va. Primary Examiner-Edward G. Favors AttomeyCristen, Sabol and OBrien [54] ELECIITRIC IGNITER 4 Claims 3 Drawing Figs.

[52] US. Cl 431/254,

219/270, 219/347 ABSTRACT: An electric ignition System for burners utilizing [51] Int. Cl F23q 13/00 an igniter having a source of high intensity light and a reflector [50] Field of Search... 431/254, for focusing the light at a point within igniting proximity of the 219/347 270 l7/( q burner to provide a point of high temperature for ignition of 240/(Inquired) fuel emanating therefrom.

ELECTRIC IGNI'I'ER BACKGROUND OF THE INVENTION The present invention pertains 602,074 electrical ignition systems for burners and more particularly to an electrical ignition system utilizing focused light from THRUST source of high intensity light to provide ignition for the burner.

Prior art ignition systems of the type to which this invention pertains generally utilize a pilot flame to ignite the burner when flow of gas is provided thereto and, after ignition, to insure fuel continuity to the burner. Pilot flames generally have a disadvantage in that they are subject to malfunction or outage for reasons in addition to burner malfunction or failure of fuel supply. For example, dust or lint can clog the pilot fuel, choking ofi the flow of fuel thereto or drafts or other ambient conditions can extinguish the flame.

Electric igniters have been found to be more desirable than pilot flame igniters in that they somewhat overcome the above disadvantages of the latter-type igniter. Electric igniters have, however, not been commonly used in the past since they require relatively complex timing and electrical relay systems to cycle energization of the igniters in order to obtain maximum life and to prove the existence of the burner flame.

Spark-type electrical be eliminated furthermore require complex and expensive circuitry to provide the high voltage necessary to furnish the spark. Glow wire igniters require complex circuitry to minimize the time they are energized at SUMMARY OF THE INVENTION The present invention provides an improved igniter for burners which avoids the disadvantages of the prior art igniters by furnishing means to ignite the burner from a point remote from the burner flame thereby avoiding high temperature deterioration of the igniter structure.

The invention furthermore provides an igniter for burners capable of being placed in such a manner that the structure thereof is remote from the burner flame by furnishing a source of high intensity light and reflecting means for focusing the light within igniting proximity of the burner.

The invention also fumishes means to utilize high intensity light sources for burner ignition by providing an ellipsoid reflector structure surrounding the light source for focusing light therefrom above the burner.

In a preferred embodiment, this invention provides a gas burner igniter including a high intensity source of light adjacent the burner; ellipsoid reflector means around the light source configured and arranged with respect to the light source to focus light therefrom immediately above the burner to thereby provide a point of high temperature ignition for the burner.

These and other objects and advantages of the present invention will become apparent to those skilled in the art by reference to the following description when viewed in conjunction with the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a partially sectioned schematic diagram of an embodiment of an electrical ignition system in accordance with the invention;

FIG. 2 is an enlarged sectional view of the igniter of FIG. 1 taken along the line 2-2 thereof; and

FIG. 3 is a sectional elevational view of another igniter constructed in accordance with the invention.

DESCRIPTION OF PREFERRED EMBODIMENTS A first embodiment of an electrical ignition system according to the present invention is shown in FIG. I. A burner 10 is connected through conduiting 12 and a solenoid valve 14 to a suitable source of gas supply. An igniter,

indicated generally at 16, is disposed adjacent the burner 10 and is aligned relative thereto so as to provide a focus point in the gas stream issuing from such burner.

The igniter 16 includes a high intensity lamp 18 mounted in a housing 20. The housing is provided with a highly polished ellipsoidal inner surface 22 surrounding the lamp l8 and configured to reflect light emanating therefrom through an opening 24, formed in an end of the housing opposite the mounting point of the lamp 18, to a focal point 26 exterior of the housing 20 and immediately adjacent the upper surface of the burner 10.

In order to enhance the ignition results, a high temperature reflective member 27 is carried by the burner 10 and disposed at the focus point 26; this will insure the focus point being located in the gas stream.

The lamp 18 is connected to terminals of a power source (not shown) through

conductors

28 and 30 and a thermostatically controlled switch 32. The electrical winding of thesolenoid valve 14 is connected to the terminals of the power source through the thermostat switch 32, a conductor 34, a thermistor 35 and a conductor 36.

In operation, the device is energized by closing of the thermostat switch 32 responsive to ambient temperature conditions in the space being heated by the burner 10. The lamp 18 is energized and the light emanating therefrom is focused at point 26 to produce a point source of heat. Simultaneously, the light heats the thermistor 35 which, when the temperature reaches one design level, acts in effect to complete the circuit between

conductors

34 and 36 and energize the solenoid 14 to provide flow of gas to the burner 10. Such an arrangement provides a delay between energization of the igniter 16 and flow of gas to the burner 10 for ignition by the heat concentrated at point 26.

As is known in the art, suitable timing mechanisms or thermostatic devices may be placed in the line of the

conductor

28 or 30 to deenergize the lamp 18 after a suitable length of time or after ignition of the burner occurs as is sensed by heat transmitted to the thermostatic device. Flame proving devices, as are also known in the art, may be provided to recycle the ignition device in the event of outage of the flame in the burner 10 as may be sensed by the thermistor 35, which upon such outage, will automatically shutdown the flow of gas to the burner 10 by closing the valve 14.

As an example, an igniter in accordance with the invention was constructed with the housing 20 being formed of aluminum and the surface 22 of ellipsoidal shape such that the focal point was at 1.50 inch centers from the lamp 18. The surfaces 22 were polished to a surface finish of high reflectability. A 12 volt DC high intensity lamp (quartz iodine) was energized from a 12 volt DC source of power and temperatures in excess of I300 F. were measured at the focal point of the igniter.

In order to obtain greater temperatures at the focal point, it is contemplated that the concentrating effect of the ellipsoidal surfaces may be augmented members; an optical lens. Referring now to FIG. 3 of the drawings, an embodiment in accordance with the invention incorporating such a lens is illustrated at 116. Components of the embodiment of FIG. 3 corresponding to like components of the preceding embodiment are indicated by like numerals with added. A housing 120, provided with ellipsoidal inner surfaces 122, as in the embodiment of FIG. 1, is formed with a tubular extension 124 at the open end thereof. A condenser lens 138 is mounted in the extension 124 and serves to condense and further increase the intensity of heat at the focal point 126 of the igniter.

The use of the optical lens 138 permits the invention to be utilized with a variety of types and sizes of burners; in addition to creating higher temperatures, the focal point may be extended so as to be at anywhere between 2 to 6 inch centers for use with many burners and may be extended even longer than at 6 inch centers from the lamp for use with burners of an unusual size or type.

Inasmuch as the present invention is subject to many variations, modifications and changes in detail, it is intended that all matter contained in the foregoing description or shown in the accompanying drawing shall be interpreted as illustrative and not in a limiting sense.

lclaim:

1. An igniter for gas burners comprising in combination:

gas burner means;

a high intensity incandescent lamp disposed adjacent said burner means;

reflector means around said lamp, said reflector means including a housing having a polished ellipsoidal inner surface, said incandescent lamp being mounted through one end of said housing coaxial with the axis of generation of said ellipsoidal surface, the other end of said housing defining an opening coaxial with said axis, and said ellipsoidal surface extending completely from said one end of said housing to the other end thereof and cooperating with said lamp to focus light emanating from said lamp at a point on said axis remote from said reflector means and within igniting proximity of said gas burner means; and

high temperature reflective means disposed at said point of focus of light from said incandescent lamp whereby a high temperature is provided at said point for ignition of said gas burner means.

2. The invention as recited in claim 1 wherein said focal point is disposed at 1.5 inch centers from said lamp.

3. The invention as recited in claim 1 wherein an optical lens is disposed in the opening defined by the other end of said housing.

4. The invention as recited in claim 1 wherein said burner means comprises a burner, conduit means connecting said burner to a source of gas supply, and solenoid actuated valve means in said conduit means to control a flow of gas therethrough, and including a thermistor disposed coaxial to said axis of said igniter and on the opposite side of said burner therefrom, and means including conductors connecting said solenoid valve to a source of electrical power, said thermistor being disposed in series with said conductors to control the energization of said solenoid valve in response to energization of said igniter.

Claims

1. An igniter for gas burners comprising in combination: gas burner means; a high intensity incandescent lamp disposed adjacent said burner means; reflector means around said lamp, said reflector means including a housing having a polished ellipsoidal inner surface, said incandescent lamp being mounted through one end of said housing coaxial with the axis of generation of said ellipsoidal surface, the other end of said housing defining an opening coaxial with said axis, and said ellipsoidal surface extending completely from said one end of said housing to the other end thereof and cooperating with said lamp to focus light emanating from said lamp at a point on said axis remote from said reflector means and within igniting proximity of said gas burner means; and high temperature reflective means disposed at said point of focus of light from said incandescent lamp whereby a high temperature is provided at said point for ignition of said gas burner means.