The invention relates generally to gas burning units, such as vent free log sets, fireplaces, wall heaters and similar devices and, in particular, to an apparatus and methods by which fuel lines may be selected, and more particularly, the type of fuel and airflow to a burner of a gas heating unit may be selected and regulated.
Currently, heating units, such as fireplaces, are desirable features in the home. Devices that burn non-solid materials, such as gas, or that produce heat electrically have gradually gained popularity. Like wood, the combustion of gas can provide “real” flames, and heat, but oftentimes entails a careful mixing of gas and air for desired or optimal performance, and a realistic flame. This aspect of the gas fireplace, and similar appliances, typically involves the delivery of air for combustion to an arrangement or device where the air is mixed with gaseous fuel, e.g., natural gas (NG) and liquid propane (LP) (“gas”). Clearly, it is advantageous that the air and gas are mixed at a ratio for proper combustion. Then, the mixed air and gas are delivered to a burner element or member, and ultimately provided to a combustion chamber of the fireplace. The mixing of air and gas is oftentimes accomplished in the burner itself.
There has also been a desire by some, such as stores and dealers that sell fireplaces and the like, to have a unit that can operate on different kinds of fuel. In many homes and other buildings, there may be NG or LP available. Sellers may therefore ask for a unit that can be adapted for either NG or LP, depending on what source of gas is available, or desired for the installation. Accordingly, units that may be configured to operate with more than one fuel source were developed. These are typically referred to as “dual-source” units. For example, the burner element may include a valving system that, when in one position, allows the unit to operate with a first fuel, and when in a second position, allows the heating unit to operate with a second fuel. These dual-source units are typically set up so that a choice of fuel is made by the installer when the unit is first put into operation. While dual-source burner units have been in the art for decades, there is always a desire to make the units simpler to use and lower in cost.
Further, when used indoors, longstanding regulations also require that an oxygen depletion sensor or system, be provided. The ODS is used to ensure that if there is a significant drop in the oxygen in the area of the unit, the fire will be extinguished.
In accordance with an aspect in one embodiment, a valve configured to allow selection of a fuel is provided with an associated shutter source for mixing air with the chosen fuel. The valve is essentially set up to operate in two configurations: one for use with natural gas (NG), and the other for use with propane (LP). In this embodiment, gas flows to selected pilot mechanisms associated with respective oxygen depletion sensing devices (ODS). A selector knob is mounted on an axel or rod of the valve, which is associated with an internal valve mechanism that rotates with the axel to open and close passageways in a manifold through which gas flows and is directed. The gas flow controlled by the valve is determined by whether the knob is placed in an NP or LP position.
An innovative shutter mechanism for controlling the flow of air into a burner, and particularly a mixing chamber associated with the burner for mixing the gas with air, is provided. The shutter mechanism preferably in one embodiment has a sleeve element which is tubular in shape, and which surrounds a tubular burner part, such as a lead-in segment to the burner element. This segment may comprise a mixing chamber, where ambient air is mixed with the selected fuel. The sleeve element in this version has at least a portion which is a cut-out or open area through the sleeve.
The tubular burner part has at least one opening or port which extends into the tubular burner part, and provides an airflow passage for air into the tubular burner part, so that the air can mix with gas flowing through the burner unit. In this embodiment, the sleeve element is located so as to rotate about the axis of the tubular burner part in a manner to open and close the airflow passage of the tubular burner part, by appropriate rotary movement of the sleeve element to place its sleeve opening in alignment with the airflow passage of the tubular burner part, or out of alignment. Depending upon how the opening/passage alignment is selected, more air enters into the mixing chamber for LP, or little to no air through the tubular burner part passage for NG.
In this embodiment, a first gear or sprocket is secured to the sleeve element, such as concentric with the sleeve element (i.e., the gear teeth extend radially from the sleeve element). A second gear or sprocket is secured to the knob or axel of the valve. The first and second gears are arranged to be engageable, such as in a right-angle arrangement with teeth meshing.
Accordingly, when the selector knob is rotated to a selected position (NP or LP), the valve axel turns and the sleeve element rotates in conjunction with the valve movement. The innovative shutter thus works in conjunction with the selector knob rotation.
In one aspect of the invention, a shutter device for use in a dual-fuel gas burner apparatus has a valve with a manifold therein, through which a first and a second gas are selectively routed. The valve preferably has a rotary axel which when rotated on its axis communicates first and second gases with a respective pathway in the manifold.
A knob is provided on the axel which is manually rotatable to select a first gas position or a second gas position. There is a burner mixing chamber within which a selected gas passes. The mixing chamber has a mixing opening for allowing ambient air into the mixing chamber interior to mix with gas therein. A cover is movably mounted to change the area of the mixing opening, and thereby the airflow therethrough; the airflow may be substantial in one orientation, or substantially or totally eliminated by movement of the cover in another orientation.
Movement of the cover in this embodiment is effected with a first gear mounted to turn with the axel. A second gear is mounted to move the cover. The first and second gears are engaged, whereby rotation of the selector knob places the cover in a position desired for a selected gas.
In one preferred aspect of the invention, the first and second gears are toothed gears, or sprockets, having teeth engaging in use. For example, the first gear is a first sprocket having radially extending teeth over at least a portion thereof, and the second gear is a sprocket having radially extending teeth over at least a portion thereof.
In the foregoing embodiment, the axel is biased into a locked condition in which the gears are engaged. When the axel is pushed against the bias, it becomes unlocked and rotatable, sufficient clearance in the gears allows inward motion of the knob without binding and facilitates radial meshing.
In one form, the shutter device has a burner mixing chamber which is generally circular in radial cross section. The cover is formed as a sleeve element co-axial with the burner chamber, and having a part which overlies the mixing chamber opening in one orientation to reduce if not substantially close airflow to the mixing chamber. In another orientation, the sleeve has at least one open area or cutout therethrough, which aligns with the one or more openings in the burner mixing chamber sidewall, for airflow into the mixing chamber. The sleeve is rotatably mounted on the burner mixing chamber, with the second gear being fixedly mounted to the sleeve.
In another aspect of the invention, the shutter device may further include an auxiliary airflow device for providing another airflow to the mixing chamber interior. Here, the auxiliary airflow device has a first plate with at least one first plate orifice therethrough, where the first plate orifice communicates with the mixing chamber interior, and a second plate having at least one second plate orifice therethrough which communicates with ambient air. The first and second plates are in facial engagement and rotatable relative to each other, such that the first plate orifice can be placed in alignment with the second plate orifice to provide an auxiliary airflow to the mixing chamber in a second position, and reduce if not substantially close the auxiliary airflow to the mixing chamber in a first position wherein the first and second plate orifices are not in alignment. In still another aspect of the invention, a shutter mechanism for controlling an airflow into a burner mixing chamber, is disclosed. The burner mixing chamber may receive a first gas flow or a second gas flow depending upon selection of the first or second gas flow by a manually operated selector mechanism. Here, a burner part has a mixing chamber opening to ambient air communicating with the mixing chamber. The burner part is preferably tubular and has a longitudinal axis.
A cover is mounted to overlie the mixing chamber opening in one orientation to reduce if not substantially close airflow through the mixing chamber opening, and to expose the mixing chamber opening in another orientation. In this embodiment, the cover moves along said longitudinal axis according to selection of the first or second gas flow. This linear movement is in contrast to the rotational movement of the covers of the embodiments previously discussed.
Movement of the cover is accomplished with a biasing member, such as a coil spring, biasing the cover to move between one orientation or another. The biasing member is actuated by the selector mechanism in this embodiment. That is, when a pathway for one gas flow is selected, such as between NG or LP, the selector mechanism also would move the cover (assuming the cover needs to be moved for that type of gas).
In one form of the foregoing embodiment of linear moving shutter, the selector mechanism includes a plate mounted orthogonal to the tube longitudinal axis. This plate is movable about the longitudinal axis. A rod is connected to the cover and has a rod end engaging the plate along a face of the plate. So engaged, the rod presses the cover against the bias of the biasing member in one orientation, essentially spring-loading the cover in that orientation. This may be to place the cover in an open position relative to the opening (or openings) to the mixing chamber.
The foregoing plate in this version is movable, as noted, and has an aperture, such as a notch, formed therethrough. When the plate is moved to another orientation, the rod end becomes disengaged from the plate face, passing through the notch. The bias applied to the cover thereby moves the cover along the burner tube to a closed (or covering) position over the opening(s) to the mixing chamber.
Besides operating the shutter as just described, another aspect of the invention is in the selector mechanism itself, for selecting and routing a first or a second gas flow to a burner unit of a gas-fired appliance. The burner unit could further include a pilot light, associated ODS and first and second pilot gas lines related to the first and second gas flows in a preferred form.
The selector of this aspect of the invention has a manifold with a burner gas inlet for a burner gas flow and a pilot gas inlet for a pilot gas flow, a burner gas outlet to the mixing chamber, a first pilot gas outlet to the first pilot gas line and a second pilot gas outlet to the second pilot gas line.
A plate member, such as that just previously discussed, is mounted to move in the manifold between the inlets and outlets. The plate member has a handle part located for manual movement of the plate, as by an installer, between a first orientation for the first gas flow and a second orientation for the second gas flow.
The plate member includes at least one pilot gas aperture therethrough which communicates (e.g., connects) the pilot gas inlet with either the first or the second pilot gas line, depending on either the first or second orientation being selected. There is at least one burner gas aperture through the plate which communicates (e.g., connects) the burner gas inlet with the burner gas outlet. In one version, the plate member has a first and a second burner gas aperture, and either the first or second aperture communicates with the burner gas outlet depending on which of the first or second orientation are selected. These burner gas apertures may be sized for a specific type of gas being supplied to the burner, as in a dual-fuel type burner. Advantageously, this novel selector also operates a linear shutter mechanism such as that described.
The aspects, advantages, features and details of the invention will be further understood in consideration of the following detailed description of certain embodiments taken in conjunction with the drawings, in which:
In the following detailed description, reference is made to the accompanying figures, which form a part thereof. In the figures, the same numbers typically identify similar components, unless context dictates otherwise. The illustrative embodiments described in the detailed description, figures, and claims are not meant to be limiting. Other embodiments may be utilized, and other changes may be made, without departing from the spirit or scope of the subject matter presented herein. It will be readily understood that the aspects of the present disclosure, as generally described herein, and illustrated in the figures, can be arranged, substituted, combined, separated, and designed in a wide variety of different configurations, all of which are contemplated herein. For instance, while the invention is described hereafter in the context of a fireplace burner, it will be understood that the technology can be readily applied to applications in wall heaters and other types of “fires.” Further, while this particular application for a fireplace is adapted for a so-called dual-fuel version, the invention may have application to routing the same kind of fuel along different selected paths.
Turning now to
One or the other gas is fed from a source to a typical regulator unit 22, via a connector inlet opening 23. This regulator unit 22 is one supplied by Maxitrol. It is an adjustable regulator that is adaptable for either LP or NG, which are supplied at different pressures. From the regulator 22, the gas progresses through tube 25 to a standard-type main controller 27. In this version, a SIT 630 Eurosit controller 27 was used. The controller 27 has a gas level control knob 28 for adjusting the flame, as well as “off” and “pilot” positions. A typical igniter 29 for the burner would also be provided.
Gas passes out of the controller 27 to a main gas line 30 (see, e.g.,
Line 37 goes directly to the first pilot and ODS 18 assembly, which as will be further understood in the discussion below, is always fed (i.e., in NG or LP mode) in this embodiment. The other line 38 goes to the selector valve 36 and into a manifold therein, connecting to a rear side nipple 40 of the valve. This pilot gas line 38 input communicates through the valve manifold to a pilot gas line output 42 via connection to a top nipple 44. The pilot gas output line 42 then connects with the second pilot and ODS 16 assembly.
Referring now to
Gas from a nozzle 50 is ignited and then provides a steady flame to one (for LP) or both of the two thermocouples 48 (for NG), depending upon which of NG or LP gas has been selected. The flame remains steady, provided that the oxygen content in the vicinity remains above a threshold level (typically around 18 percent or so). If the oxygen level drops below the threshold, the flame then lessons in strength as detected by the thermocouple (effectively, a temperature drop). This then triggers conventionally known circuitry associated with the ODS to close a gas control valve, shutting of the fuel supply to the burner 10.
The selector valve 36 is a valve made by Copreci, model no. CPM 21400. Such a valve type is also shown in U.S. Pat. No. 7,766,006, which can be referred to for further details concerning this valve, its internal manifold structure, and its operation. Briefly, the valve 36 has an internal manifold which serves to route fuel through the valve to a certain outlet or outlets. The route is determined by rotation of an axel 54 e.g., (
NG if connected will be fed to line 37, and to line 42 as well in the other or second configuration of the selector valve (shown in the NG position in
It is considered desirable to provide a certain amount of air to the gas in order to get a flame of a yellow color, for instance. However, NG requires less air to be mixed with it than LP at the pressures of the gas being admitted to the burner tube 14. The present invention therefore provides a novel shutter device for controlling the amount of air to mix with gas within the burner tube 14.
Gas admitted to the burner tube passes through the main line 30 through the selector valve to be admitted at one end of the burner tube 14. This part of the burner tube constitutes a burner mixing chamber 14a, where air and gas will now be combined within the burner tube. Burner tube 14 also has a short internal tube 58 which serves to inject gas beyond the point of the openings 60 (i.e., downstream from the openings). The burner mixing chamber has a pair of openings 60 formed therein, only one of which is shown in
A sleeve member 62 is mounted concentrically with the burner tube 14a, so as to overlie the openings 60. The sleeve is sized so as to be just slightly greater in internal diameter than the external diameter of the burner tube 14a. Both the burner tube 14a and sleeve 62 are circular in cross section. The sleeve is rotatable about the burner tube 14a. One end of the sleeve member 62 is prevented from movement along the long axis of the burner tube 14a by a fixed stop 64 on the top, as well as bottom, of the tube 14a, against which an end of the sleeve abuts. The stop 64 can be a weldment, for instance.
Sleeve member 62 has a pair of cutout areas 66 formed therethrough, only one of which is shown in
Likewise, the cutouts 66 for the sleeve member 62 can be adjusted for the amount of coverage of an opening desired, such as permitting full opening, or perhaps something less than full. Other than the cutouts 66, the rest of the sleeve member 62 in this embodiment is closed, i.e., it is a solid tube except for the cutout areas 66. Thus, in a first configuration which is for supplying a significant airflow to the mixing chamber, for LP, the sleeve member 62 is placed so that the cutout areas 66 overlie the burner tube openings 60, allowing a full open position (depicted in
The standard selector valve 36 has a locked position for the axel. The axel has an internal spring bias, which forces the axel slightly outboard (i.e., outwardly relative to the internal manifold of the valve), and places internal structure of the axel into a position where it cannot rotate. When the axel is pressed against the bias, as by someone pushing the selector knob 56 inboard, it can then be rotated. The valve will initially be set for one fuel position and initially in the locked position; this is in effect a default fuel set position. If the other fuel is to be selected, then the knob/axel is pushed in and turned to that other gas position. The selector valve 36, along with the knob 56, are mounted to a vertical bracket 80, which is fixed to the base plate arrangement 13.
In order to rotate the sleeve member 62 to a desired orientation, in association with the type of fuel selected, a pair of gears or sprockets are used. A first sprocket 70 is fixed to the axel (or it could be fixed to the knob 56, for that matter). First sprocket 70 has teeth 72 that extend radially relative to the axel in this embodiment.
A second sprocket 74 is fixed to the outside of the sleeve member 62. Second sprocket 74 has radially extending teeth 76 along at least a part of the perimeter of the second sprocket 74. Second sprocket 74 can be welded to the sleeve member, for instance. Second sprocket 74 also is associated with an endplate structure mounted to this end of the burner tube, that will shortly be discussed, in a manner which thereby locates this end of the sleeve member 62 against movement along the burner tube, but allows rotation about the axis of the burner tube.
In this embodiment, the first and second sprocket teeth are out of engagement with the axel in the locked position. This out of engagement arrangement is depicted in
The aforementioned endplate structure to the burner mixing chamber will now be described. Gas from the main gas line 30 passes into the valve 36, and then from the valve through a port into the end of the burner tube. The burner gas passes through a main port through a pair of discs that are in general facial engagement. One disc is mounted to turn with the sleeve member 62, but has a plurality of small orifices therethrough, which communicate with the burner tube mixing chamber. The second disc has ports also formed therethrough, and the ports communicate with ambient air. In one configuration the ports align with the orifices of the fixed disc. Here, four orifices and four ports are used, generally located symmetrically about the discs. The second disc is fixed against rotation. When the ports and orifices align a further airflow is allowed into the mixing chamber along the axis of the burner tube mixing chamber. This is utilized in the LP mode. When in the NG mode, the ports are rotated or placed out of alignment with the orifices, and thus close this auxiliary supply of air. The number of ports and related orifices may be selected and located as desired, so long as the requisite airflow in this version is provided in the one orientation.
Turning now to
Gas burner mixing chamber 14a uses a sleeve member 62 having cutout areas 66. The main gas line for the burner connects to nipple 185, such as via a pathway from the valve 136. Referring now to
Inboard from the sprocket 174, and extending into the mixing chamber 14a, is a gas injector tube element 158. The tube element 158 has a base 159 which has a plurality of apertures 161 which will receive screws (or bolts or other fixation elements) in a manner about to be described. There is an annular groove 167 around the base 159 which, when the tube element is assembled with the mixing chamber 14a, will receive a spring clip (not shown). The spring clip fits around the upstream end of the mixing chamber 14a, and extends through slots 168 formed in the mixing chamber end.
Nipple 185 for the main gas feed is part of an end cap 195, which has a plurality of through bores 196 which receive the screws (or bolts or other fixation elements) to connect the end cap 195 with the base 159 of the tube element 158. Looking at
It will therefore be seen that, when this embodiment of the shutter device of this invention is assembled, the sprocket 174 turns the sleeve member 62 about the mixing chamber 14a, to either open or close (fully or substantially) the openings 60 to the mixing chamber interior. This is accomplished by engaging the teeth 172 of the knob 156 with the sprocket teeth 176, and then turning the knob to drive the sprocket about its axis. Movement of the sprocket 174 in turn rotates the disc 189 to align with one or the other of the orifices 181, 182, depending on the type of fuel selected (NG or LP). Locking and unlocking of the knob for rotation is as described in relation to the previous embodiment.
Turning now to
The output housing 359 contains a nozzle or gas injector tube 358 that feeds gas from the main gas line 30 into the gas burner mixing chamber 314. The output housing 359 may be affixed to the mixing chamber 314 via a screw or other fixation element (not shown). That is, the mixing chamber 314 can be formed as an integral part of the burner tube at this end of the burner tube, or it may be attached thereto. The mixing tube/burner tube terminates in an end opening, which is sized in internal diameter to fit over a mounting shoulder 363 formed around the outside of the upstream base of the gas injector tube 358. This can be a fairly snug fit, with a glue or other sealant applied, and the aforementioned screw (or the like) inserted through the sidewall of the end of the burner tube and into the mounting shoulder 363 to further affix the mixing tube/burner tube in place.
A cover or sleeve 362 is mounted concentrically with the mixing chamber 314, so as to substantially overlie a primary opening 360 in the mixing chamber 314. The sleeve 362 in this embodiment is sized so as to be just slightly greater in internal diameter than the external diameter of the mixing chamber 314. The sleeve 362 is adapted to freely slide along the longitudinal axis of the mixing chamber 314. As will be understood by those of skill, however, other types of covers could be designed to open or close one or more apertures providing air to the mixing chamber 314.
The primary opening 360 permits ambient airflow into the mixing chamber 314 sufficient to achieve an optimal or desired burn depending upon the type of gas selected. For example, as depicted in
The sleeve 362 contains a flange or lip 370 mounted toward its outboard end and adapted to receive a biasing force from the biasing member 372. In the present embodiment, the biasing member 372 is a coil spring, although alternative biasing members and different arrangements to bias the sleeve 362 may also be used without departing from the spirit and scope of the invention. The biasing member 372 is adapted to apply a force to the outboard face of a radially extending flange or lip 370 formed on the sleeve concentric with the longitudinal axis of the sleeve, which longitudinal axis is also the same as that of the mixing chamber 314, with the bias influencing the sleeve 362 toward the end of the mixing chamber/burner tube, into what has been described as a closed orientation. The coil spring biasing member 372 is retained between the lip 370 mounted to the sleeve, and a second flange or lip 380 formed around the burner tube and concentric therewith mounted to the mixing chamber, thereby tending to bias the two respective lips 370, 380 apart from each another.
Mounted, typically by welding, to the inboard face of lip 370 is a rod 374. In the open position, one end of rod 374 engages the plate 389 along a face or surface of the plate which will be characterized, simply for reference, as the “downstream” face—upstream and downstream being used relative to the gas flow in this vicinity. For purposes of illustration, the direction of gas flow is indicated by the arrow in
As discussed, the output housing 359 contains a nozzle 358 extending into the mixing chamber 314. The nozzle 358 in this version is generally conic in cross-section. For example, in an embodiment the nozzle 358 may be approximately 0.650 inches in diameter at the base and 0.20 inches at the tip, measuring approximately 1 inch from base to tip. The nozzle also contains an O-ring or other gasket 357 seated in a groove about the inboard (upstream) opening of the nozzle 358. When assembled, the O-ring 357 is compressed between the output housing 359 and plate 389, creating a seal at the interface with the plate face.
The output housing contains a number of apertures 361 adapted to receive screws or other fixation elements, as will be described. Also located on the output housing 359 are two pilot outlets 411 and 412 adapted to receive LP or NG pilot gas, respectively, flowing through the device as discussed below. Pilot outlets 411 and 412 feed into their respective LP and NG pilot gas flow lines and to respective pilot outlets and associated ODS systems, in a manner described previously.
In the present embodiment, the input housing 395 is located inboard (upstream) of and fixed to the output housing 359 via screws or other fixation elements passing through apertures 396 in the input housing 395 and being received by apertures 361 in the output housing. Input housing 395 has a gas inlet 385 adapted to connect to the main gas line 30, whether LP or NG, via threads or other suitable fixation means. At the base of the gas inlet 385 and passing completely through the input housing 395 is a gas orifice 399. Gas from the main gas line 30 will pass through the gas orifice 399 for eventual admission into the mixing chamber 314, using a selected orifice in the plate, as will be described below. Mounted to the downstream side of the input housing 395 and surrounding the area of the burner gas inlet is an O-ring in an appropriate circular groove.
Input housing 395 also has a pilot inlet 390 similarly adapted to connect to either the LP or NG pilot gas line 38, depending upon the user's selection. Pilot inlet 390 is configured in a Y-branch orientation whereby gas is directed through one of two pilot orifices 391 and 392. The selection of which pilot orifice the pilot gas flows through is determined by the orientation of the plate 389, discussed below. Both the two pilot orifices 391 and 392, as well as the gas orifice 399, may contain a concentric groove about their inboard face for receiving a sealing element, such as an O-ring.
Located between the input housing 395 and output housing 359 is the plate 389 adapted to rotate about the longitudinal axis of the mixing chamber 314. Disposed on the plate 389 is a selection handle 400 whereby the user may select between LP and NG gas configuration. The plate 389 contains first and second gas openings 382 and 381 through which gas from the main line 30 passes from the gas orifice 399. First gas opening 382 is larger and sized for NG, while second gas opening 381 is slightly smaller and sized for LP. For example, gas opening 382 may be between 0.124 and 0.126 inches in diameter, while gas opening 381 may be sized between 0.094 and 0.096 inches in diameter. Rotation of the plate 389 via selection handle 400 aligns the appropriate one of the two gas openings with gas orifice 399 in the input housing 395. Accordingly, alignment of the gas orifice 399, the selected gas opening 381 or 382 and the nozzle 358 forms a conduit through which gas may pass into the mixing chamber 314 from the gas line 30.
Plate 389 also contains pilot openings 401 and 402 adapted to align with pilot orifices 391 and 392, respectively, depending upon the selection of either LP or NG by the user. For example, in the present embodiment, rotation of the plate 389 into the LP orientation will place gas opening 381 into alignment with gas orifice 399, while simultaneously aligning pilot opening 401 with pilot orifice 391 and pilot outlet 411. Cutouts 414 in plate 389 permit passage of the screws or other fixation elements through the plate 389 such that the fixation elements may mount the input housing to the output housing to complete the manifold, while allowing the plate to move (with the screws passing along the arcs of the cutouts).
It will be therefore be evident to those in the art that, when this embodiment is assembled, rotating the plate 389 via the selection handle 400 permits the user to easily select between LP and NG burning modes. This is accomplished by aligning the appropriate pilot orifice 391 to its respective pilot opening 401 and pilot outlet 411, while similarly aligning the appropriate gas opening 382 with the gas orifice 399 and nozzle 358, all in one rotational motion. The appropriate ambient air conditions in the mixing chamber 314 are similarly coordinated via the user's selection using the selection handle 400.
A plate 389 has been chosen in this embodiment as a presently preferred element to effect alignment of the various orifices depending on the gas flow selected. The form of the plate also lends itself to operation of the shutter, providing a surface over which the end of the rod easily travels. It will be understood that other constructs may be adapted for similar use, with the basic concept being to move an element between opposed parts of a manifold to thereby connect (and conversely block) desired input and output channels for gas flows to respective pilot assemblies and the burner (via a mixing chamber, if used, as here). The foregoing third embodiment as described eliminates the use of a selector valve of the type described with the first two embodiments having radial outlets, since the gas flows in the third embodiment are essentially along linear pathways through the manifold inlets to the manifold outlets.
Thus, while the invention has been described with respect to certain embodiments, variations and modifications will be recognized by those of skill in the art which will nonetheless come within the spirit and scope of the invention, as further set forth in the claims which follow.
The present application claims priority from U.S. application Ser. No. 61/779,369, filed Mar. 13, 2013, which is incorporated by reference herein in its entirety.
Number | Date | Country | |
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61779369 | Mar 2013 | US |