Patent Application
20130337389
The present disclosure relates generally to gas-fired burner assemblies.
Gas-fired appliances that cycle on and off often have a pilot burner that provides a flame whose purpose is to light the main burner of the appliance when there is a call for heat. In some cases, pilot burners can also provide a safety control mechanism to help ensure that if the pilot flame is extinguished for any reason, then the supply of gas to the whole appliance is cut off.
Pilot burners for gas-fired appliances often include a pilot burner tube which defines a flame opening at one end, a thermo-electric device and a spark source. The relative alignment and/or positioning of the various components of a pilot burner can affect the operation and/or reliability of the pilot burner. In some cases, several machined parts, fixtures, and/or assembly tools are required to help ensure that the pilot burner's functional tolerances are maintained, which can be difficult. Also, it can be desirable to allow a technician or other person to remove and/or replace one or more of the components of a pilot burner in the field. In many cases, this can be difficult and time consuming given the construction of many conventional pilot burners.
The present disclosure relates generally to gas-fired burner assemblies, and more particularly, to pilot burner assemblies for gas-fired appliances. In one illustrative embodiment, a pilot burner assembly may include a bracket and a resilient clip, which together, help maintain at least some of the pilot burner components in a desired configuration. In one example, the bracket may include a first plate, a spaced second plate, and a third plate connecting the first plate and the second plate. In some instances, the first plate, the second plate and the third plate may collectively form a generally U-shape bracket, and may be a single piece if desired, but this is not required. The first plate and the second plate may each include an aperture, and when the pilot burner is assembled, a thermo-electric device may extend through the apertures in the first plate and the second plate. In some cases, the bracket may be configured to allow a gas feed line to pass between the thermo-electric device and the third plate. A resilient clip may be used to help hold the thermo-electric device within the apertures. In some cases, the clip may also be used to help hold the bracket relative to the gas feed line. In one example, the resilient clip may be positioned between the thermo-electric device and the gas feed line. The resilient clip may apply a bias force to the thermo-electric device in a first direction, which may bias the thermo-electric device against side walls of the apertures in the first and second plates to help hold the thermo-electric device in relation to the bracket. The clip may also apply a bias force to the gas feed line in a second direction, which in some cases, may bias the gas feed line against the bracket to help hold the bracket in relation to the gas feed line. More generally, it is contemplated that a bracket and resilient clip assembly may be used to more easily assemble, remove and/or replace one or more components of a pilot burner assembly.
The disclosure may be more completely understood in consideration of the following description of various examples in connection with the accompanying drawings, in which:
While the disclosure is amenable to various modifications and alternative forms, specifics thereof have been shown by way of example in the drawings and will be described in detail. It should be understood, however, that the intention is not to limit aspects of the disclosure to the particular examples described. On the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the disclosure.
The following description should be read with reference to the drawings wherein like reference numerals indicate like elements throughout the several views. The description and drawings show several examples which are meant to be illustrative in nature.
The thermo-electric device 18 may, for example, be a thermopile. It is contemplated that the thermo-electric device 18 may be any suitable thermoelectric device including a thermocouple or thermopile, as desired. A thermopile is a device that converts thermal energy into electrical energy. Typically, it is composed of thermocouples connected either in series or in parallel. For the pilot burner 12, it is possible for a single thermocouple to be used instead of a thermopile, but it is more common for a collection of thermocouples such as a thermopile to be used with a pilot burner. When a flame is present at the flame opening 17 of the burner tube 16, the flame or heat from the flame is directed to the body of the thermo-electric device 18. The thermo-electric device 18 then generates a voltage. The voltage may be directed to a gas valve that supplies gas to the burner assembly 10. A lack of voltage from the thermo-electric device 18, which would indicate a lack of a pilot flame in pilot burner assembly 12, may be used to close the gas valve. In this way, the pilot burner 12 may provide a safety mechanism for the flow of gas to a gas fired appliance. In some cases, the thermoelectric device may be a photo-electric device, which may generate a current based on light emitted from the pilot flame, rather than heat.
In the illustrative embodiment, the burner tube 16 is positioned generally perpendicular to the thermo-electric device 18, although this is not required. In some instances, the main burner assembly 14 may include structure to help maintain the orientation of the burner tube 16. A bracket 20 and resilient clip 22 may also be used to maintain the position of the thermo-electric device 18 relative to the burner tube 16. For example, in some instances, a bracket 20 may be used to maintain the thermo-electric device 18 within a notch or recess 15 in the lower plate 13 of the main burner assembly 14 adjacent to the flame opening 17 of the burner tube 16. In some cases, the bracket 20 may be formed from stamped metal, if desired. When so provided, certain features such as apertures, may be formed when the bracket is “blanked”. If certain features “float” during the stamping operation, such as apertures, they will tend to float together and their positions may remain relatively fixed with respect to each other. This may help maintain the functional tolerances of the pilot burner components. In the illustrative embodiment, the bracket 20 may be generally “U” shaped, and may include retention features on one or both legs of the U-channel for maintaining the thermo-electric device 18 in a desired orientation. This may allow tighter tolerances on the functional dimensions to be maintained, without requiring adjustment or complicated fixtures in the factory or in the field.
In some instances, the flame opening 17 of the burner tube 16 may be positioned under a portion of the main burner assembly 14 such that condensing water does not snuff out the pilot flame. This position may help prevent pilot flame instability and loss of pilot flame without the addition of a pilot hood or other further structure. It is further contemplated that the main burner may not direct main burner flame directly at the thermo-electric device, which may help prevent excess heat when the main burner assembly 14 is on. This may help prevent output drops in the thermo-electric device 18 when the main burner turns off.
The various components of the illustrative pilot burner assembly 12 will now be described in more detail with reference to
In the example shown, and as best seen in
The first plate 32 may include a first aperture 40. The second plate 34 may include a first aperture 42. The first aperture 40 of the first plate 32 may be generally aligned with the first aperture 42 of the second plate 34 (e.g. aligned along a common axis). In the example shown, the first apertures 40, 42 may be configured to receive the thermo-electric device 18 therethrough. While first apertures 40, 42 are shown as having a generally circular cross-section, it is contemplated that the cross-section may be of any shape desired. For example, in some instances, the apertures 40, 42 may include “V-block” features for component alignment, as shown in
Aperture 42 in the second plate 34 may include a retention feature 43 for cooperating with a retention feature 62 of the thermo-electric device 18. The retention feature 44 may include a region of reduced profile relative to the aperture 42 to provide a hard stop and to engage the retention feature 62 of the thermo-electric device 18. This may help maintain the thermo-electric device 18 in a desired position relative to the other burner assembly components, as will be discussed in more detail below. A resilient clip 22 may include a handle portion 54 and a second portion 55 extending from the handle portion 54. In some instances, the second portion 55 of the clip 22 may be positioned between the thermo-electric device 18 and main gas feed line 26. The structure of the resilient clip 22 will be discussed in more detail below with respect to
Referring to
Referring specifically to
In the illustrative embodiment, the spark source 24 may include a generally tubular structure having a first end 64 and a second end 66, with a tapered region 68 disposed therebetween. The first region 64 may have a cross-sectional area that is larger than the second region 66. As will be discussed in more detail below, the first region 64 may be received by aperture 44 on the angled portion 38 of the bracket 20. One example of a spark source that can be used with the pilot burner is a piezoelectric sparker or other type of spark source, as desired.
To assemble the pilot assembly 12, the bracket 20 may be slid over the main gas feed line 26 towards the main burner assembly 14. Once, the bracket 20 is positioned on the main gas feed line 26, the thermo-electric device 18 may be slid into the apertures 40, 42 in the first and second plates 32, 34 of the bracket. The thermo-electric device 18 may be slid upwards though the apertures 40, 42 until a bottom portion of the retaining feature 62 slides through and is disposed above aperture 42. The aperture 42 may be sufficiently large to allow the retaining feature 62 to pass through.
The aperture 42 may include a reduced dimension retaining feature 43, defined by the side wall of the aperture 42 that is away from the third plate 36. After the retaining feature 62 of the thermo-electric device 18 is slid through the aperture 42, the thermo-electric device 18 may be pushed or biased away from the third plate 36 and toward the reduced dimension retaining feature 43. The reduced dimension retaining feature 43 may be sized to accommodate the second region 60 of the thermo-electric device 18 but not the retaining feature 62, thereby creating a positive stop and preventing the thermo-electric device 18 from disassociating from the bracket 20.
As will be discussed in more detail with respect to
Once assembled, the bracket 20 and thermo-electric device 18 may be slid along the main gas feed line 26 until the thermo-electric device 18 is aligned with the pilot burner tube 16. For example, the thermo-electric device 18 may be positioned within slot 15 in the main burner assembly 14, if so provided, although this is not required. It is further contemplated that the bracket 20 may be positioned adjacent to the pilot burner tube 16 prior to inserting the thermo-electric device 18 and the clip 22. In some embodiments, once the pilot assembly 12 is aligned with the pilot burner tube 16 and the main burner assembly 14, the main gas feed line 26 may be deformed to prevent the pilot assembly 12 from moving, but this is not required. For example, the main gas feed line 26 may be bent slightly to prevent further movement of the pilot assembly 12 along the length of the gas feed line 26.
The spark source 24 may be positioned within the angled portion 38 of the bracket 20 by sliding the second region 66 of the spark source 24 through aperture 44 until the first region 64 comes into frictional engagement with protrusions 46. The new frictional engagement of the first region 64 with the protrusions 46 may maintain the spark source 24 in a desired position relative to the thermo-electric device 18 and pilot burner tube 16.
The second portion 55 of the clip 22 may include a number of curved and/or angled regions configured to engage either the thermo-electric device 18 or the gas feed line 26. In the example shown, the resilient clip 22 is configured to contact the main gas feed line 26 at a first curved region 50 adjacent to the gripping portion 54 and a second slightly curved region 48 adjacent to the second end 56 of the clip 22. The clip 22 may further include an intermediate region 52 disposed between the regions 48, 50. The intermediate region 52 may be slightly curved and may be configured to contact the thermo-electric device 18. In some instances, the intermediate region 52 may be configured to generally conform to the surface of the thermo-electric device 18. In some instances, the clip 22 may further include angled regions 57, 59 between the regions 48, 50 configured to contact the gas feed line 26 and the intermediate region 52. These regions 57, 59 may be sized such that when the clip 22 is inserted between the thermo-electric device 18 and the main gas feed line 26, a biasing force is exerted on the thermo-electric device 18 and the main gas feed line 26. In the example shown, it is contemplated that the clip 22 may be used to assemble and/or disassemble the pilot assembly 12 without tools, mounting hardware, welding, or other attachment elements.
The resilient clip 22 may have a first generally unstressed position when the clip 22 is not positioned within the bracket 20 or between the thermo-electric device 18 and the main gas feed line 26. The resilient clip 22 may have a second position when positioned within the bracket 20 and between thermo-electric device 18 and the main gas feed line 26. In the second position, the resilient clip 22 may be under stress and may provide a bias force to the thermo-electric device 18 such that the thermo-electric device 18 is biased away from the gas feed line 26 and towards the retention feature in the bracket 20. In the second position, the resilient clip 22 may also provide a bias force to the main gas feed line 26 such that the gas feed line 26 is biased away from the thermo-electric device 18 and towards the third plate 36 of the bracket 20.
In the example shown, the bracket 108 may have a general “U channel” shape that is defined by a first plate 110, a spaced second plate (not explicitly shown), and a third plate 112 extending between the first plate 110 and the second plate. In some instances, the third plate 112 may have a generally curved profile configured to generally correspond to the shape of the main gas feed line 122, but this is not required. In some embodiments, the bracket 108 and/or the main gas feed line 122 may include features configured to align the bracket 108 and/or the main gas feed line 122 in a desired orientation and/or location, as will be discussed in more detail below.
The bracket 108 may be similar in form and function to bracket 20 discussed above. The first plate 110 may include a first aperture 116. The second plate may also include a first aperture generally aligned with the first aperture 116 of the first plate 110. The apertures 116 may be configured to receive the thermo-electric device 102 therethrough. In some instances, the first aperture 116 may include a “v-block” feature 118 for component alignment. For example, the “v” shape may help align the thermo-electric device 102 in a particular orientation and/or position. While not explicitly shown, the aperture in the second plate may also include a “v-block” feature which may further help align the thermo-electric device 102. It is further contemplated that a “v” shape may also act as a retention feature in cooperation with retention features on the thermo-electric device 102 in a manner similar to the retention features described with respect to
The bracket 108 may further include an angled plate 114 extending from the first plate 110, as shown. The angled plate may include an aperture 124 configured to receive spark source 104. The angled plate 114 may be positioned to orient the spark source 104 towards a flame opening, such as flame opening 17 shown in
The pilot assembly 100 may also include a resilient clip 120 positioned between the thermo-electric device 102 and main gas feed line 122. The resilient clip 120 may be similar in form and function to the clip 22 described with respect to
In the illustrative embodiment, the bracket 206 may have a general “U channel” shape that is defined by a first plate 208, a spaced second plate 210, and a third plate 212 extending between the first plate 208 and the second plate 210. In some instances, the third plate 212 may be generally perpendicular to the first and second plates 208, 210, but this is not required. In some embodiments, the bracket 206 and/or the main gas feed line 218 may include features configured to align the bracket 206 and/or the main gas feed line 218 in a desired orientation and/or location. For example, in some instances, the main gas feed line 218 may include a region that has been deformed to include a generally flat region 220 configured to mate with the inner wall of the third plate 212. This flat region 220 may be located at a position adjacent to the main burner assembly such that when the bracket 206 is aligned with the flat region 220, the pilot assembly 200 is properly aligned with the main burner and the pilot burner tube.
The bracket 206 may be similar in form and function to bracket 20 discussed above. The first and second plates 208, 210 may each include an aperture (not explicitly shown). The apertures in the first and second plates 208, 210 may be generally aligned with one another. The apertures may be configured to receive the thermo-electric device 202 therethrough. One or more of the apertures may include features, such as a “v-block” feature, for component alignment, although this is not required. In some instances, one or more of the apertures may include a retention feature configured to cooperate with retention features on the thermo-electric device 202 in a manner similar to the retention features described with respect to
The bracket 206 may further include an angled plate 214 extending from the first plate 208, as shown. The angled plate may include an aperture (not explicitly shown) configured to receive spark source 204. The angled plate 214 may be positioned to orient the spark source 204 towards the flame opening of the pilot burner tube. Spark source 204 may include a spark rod, such as spark rod 24 shown in
The pilot assembly 200 may also include a resilient clip 216 positioned between the thermo-electric device 202 and main gas feed line 218. The resilient clip 216 may be similar in form and function to the clip 22 described with respect to
In some instances, the pilot burner tube 308 may be positioned between the upper and lower plates 304, 306. While not explicitly shown, the upper and lower plates 304, 306 may be structured to form a channel around the pilot burner tube 308 to prevent lateral movement in the burner tube 308. In some embodiments, the pilot burner tube 308 may further include a flange 312 positioned adjacent to the flame opening 310. The flange 312 may limit how far the pilot burner tube 308 can retract under the upper plate 304. This may further help maintain the orientation and/or location of the pilot flame relative to the thermo-electric device, such as thermoelectric device 18 shown in
Those skilled in the art will recognize that the present disclosure may be manifested in a variety of forms other than the specific examples described herein. Accordingly, departure in form and detail may be made without departing from the scope and spirit of the present disclosure as described in the appended claims.
