Patent Publication Number: US-9423153-B2

Title: Unregulated integrated function gas valve for a water heater

Description:
CROSS-REFERENCE TO RELATED PATENT APPLICATIONS 
     This patent claims the benefit of U.S. Provisional Patent Application No. 60/162,966, filed Mar. 24, 2009, the entire teachings and disclosure of which are incorporated herein by reference thereto. 
     FIELD OF THE INVENTION 
     This invention relates generally to water heaters, and more specifically to gas valves for water heaters. 
     BACKGROUND OF THE INVENTION 
     In a gas water heater, the water heating and temperature control system typically includes a combustion chamber located beneath a water tank and a gas heating element in the combustion chamber. The flow of gas to the combustion chamber is controlled by a gas valve assembly. The gas valve may include an elongate temperature probe assembly configured to sense the temperature of water in the water tank. The temperature probe assembly typically includes an invar rod disposed within a copper tube, and is often assembled to the gas valve assembly such that the temperature probe assembly protrudes from the gas valve assembly at roughly a right angle to a longitudinal axis of the gas valve assembly. 
     The temperature sensing probe is assembled to valve components, which are configured to open or close the flow of gas in a particular channel of the gas valve. Generally, the copper tube and invar rod assembly are configured to be positioned inside the water tank. The copper tube, having a high thermal coefficient of expansion, expands and contracts as the water temperature in the tank increases and decreases, respectively. The expansion and contraction of the copper tube acts to move the invar rod. Typically, as the water in the tank cools, the invar rod contracts and, by contracting, pushes against a lever, which causes the gas valve to allow the main gas or bleed gas to flow to the outlet of the valve and into the combustion chamber. 
     While regulated gas valves are common in the U.S., in some countries, it is more common to have unregulated gas valves. These unregulated gas valves typically include a gas cock to regulate the flow of gas into the valve, and a temperature adjustment knob to select a desired temperature setting. However, these unregulated gas valves do not typically have a safety feature to prevent the flow of gas to the valve in the event of a fire. Moreover, the use of two controls (i.e., the gas cock and temperature control knob) to operate the gas valve adds to both the parts cost and the assembly cost of the gas valve. And with two controls, there are two potential points of failure. As such, reducing the number of controls required to operate the unregulated gas valve could improve the reliability of the valve. 
     It would therefore be desirable to have an unregulated gas valve that combines the two gas valve controls into one control to save parts and assembly costs and improve reliability. It would also be desirable to have a gas valve that includes a safety feature that can prevent the flow of gas into the valve if the control knob is exposed to a fire. 
     Embodiments of the invention provide such an unregulated gas valve. These and other advantages of the invention, as well as additional inventive features, will be apparent from the description of the invention provided herein. 
     BRIEF SUMMARY OF THE INVENTION 
     In one aspect, an embodiment of the invention provides an unregulated gas valve for a water heater that includes an inlet configured to receive a gas flow into the gas valve, an outlet configured to direct a portion of the gas flow to a combustion chamber, a pilot line configured to direct a portion of the gas flow to a pilot flame, and a dial configured to regulate the flow of gas into the gas valve, and further configured to select a water temperature setting. 
     In another aspect, an embodiment of the invention provides a gas valve that includes a valve body configured to provide a flow path for a gas to a pilot line, and further configured to provide a flow path for the gas to an outlet, and a safety magnet disposed within the valve body, wherein the safety magnet, in a first position, is configured to prevent the flow of gas into the valve body, and wherein the safety magnet, in a second position, is configured to permit the flow of gas into the valve body. The gas valve further includes a pilot valve disposed within the valve body, wherein the pilot valve, in a first position, is configured to prevent the flow of gas to the pilot line, and wherein the pilot valve, in a second position, is configured to permit the flow of gas to the pilot line, a temperature adjustment screw disposed within the valve body, the temperature adjustment screw configured to vary a water temperature setting, and a dial configured to control a position of each of the temperature adjustment screw, the pilot valve, and the safety magnet. 
     Other aspects, objectives and advantages of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings incorporated in and forming a part of the specification illustrate several aspects of the present invention and, together with the description, serve to explain the principles of the invention. In the drawings: 
         FIG. 1  is a top view of a gas valve assembly according to an embodiment of the invention; 
         FIG. 2  is a front view of the gas valve assembly illustrated in  FIG. 1 ; 
         FIG. 3A  is a pictorial view of a dial usable in the gas valve assembly of  FIG. 1  according to an embodiment of the invention; 
         FIG. 3B  is a closeup view of a section of the dial illustrated in  FIG. 3A ; 
         FIG. 4  is a pictorial view of a valve body and valve cover usable in the gas valve assembly illustrated in  FIG. 1  according to an embodiment of the invention; 
         FIG. 5  is a cross-sectional view of the gas valve assembly according to an embodiment of the invention; 
         FIG. 6  is a cross-sectional view of the gas valve assembly showing a pilot valve according to an embodiment of the invention; 
         FIG. 7  is a cross-sectional view of the gas valve assembly illustrated in  FIG. 6  showing the pilot valve in a different position; 
         FIG. 8  is a cross-sectional view of the gas valve assembly showing a thermocouple and a safety magnet according to an embodiment of the invention; 
         FIG. 9  is a perspective view of the gas valve assembly; 
         FIG. 10  is a back view of the gas valve assembly; 
         FIG. 11  is a top view of the gas valve assembly; 
         FIG. 12  is a side view of the gas valve assembly; 
         FIG. 13  is a bottom view of the gas valve assembly; 
         FIG. 14  is side view of the gas valve assembly showing the side opposite of that shown in  FIG. 12 ; 
         FIG. 15  is a front view of the gas valve assembly; and 
         FIG. 16  is a pictorial illustration of a water heater that incorporates an embodiment of the invention. 
     
    
    
     While the invention will be described in connection with certain preferred embodiments, there is no intent to limit it to those embodiments. On the contrary, the intent is to cover all alternatives, modifications and equivalents as included within the spirit and scope of the invention as defined by the appended claims. 
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  illustrates a top view of an unregulated gas valve  100  according to an embodiment of the invention. The gas valve  100  includes a plastic disk-shaped dial  102  attached to a similarly disk-shaped valve body  104 . A shank  106  is attached a side of the valve body  104  opposite the dial  102 . The shank  106  is essentially annular and has a longitudinal axis  108  that is also the central axis of dial  102 . In one embodiment, the valve body  104  has threaded openings and is attached to the dial  102  and shank  106  using screws assembled into the threaded openings. 
     Having the central axis of the dial  102  aligned with the longitudinal axis  108  of the shank  106  reduces the cost of assembly in that fixturing for the components is made simpler and less expensive. Having multiple concentric components can also result in a speedier manufacturing process in that the multiple components can be located using a common reference point during assembly. Packaging is also made simpler and less expensive as the molds used to make plastic packing materials, for example, are easier to design and manufacture than molds to make packing materials for assemblies with a variety of non-concentric components. 
       FIG. 2  illustrates a front view of the gas valve  100  according to an embodiment of the invention. The front  105  of the dial  102  includes a plurality of markings  110  on a perimeter wall  112  of the dial  102 . The front  105  of dial  102  also includes a reset button  107  and a plurality of labels, each label associated with one or more of the plurality of markings  110 , wherein each label describes the function to be performed when the marking associated with that label is aligned with a fixed reference  111  on the valve body  104 . In the embodiment shown in  FIG. 2 , the plurality of labels includes CERRADO (OFF), PILOTO (PILOT), FRIO (COLD), TIBIO (WARM), and CALIENTE (HOT). A pilot line  113  and a thermocouple  117  are attached to the valve body  104 . In one embodiment, the pilot line  113  and the thermocouple  117  are attached using fittings that are threaded into openings in the valve body  104 . 
       FIG. 3A  illustrates a back side  115  of dial  102  according to an embodiment of the invention. In the embodiment shown, the dial  102  is made from plastic and includes a molded-in or integral gear  114  at the center of the back side  115  of dial  102 . The gear  114  is formed onto a cylindrical projection  116  at the center of the back side  115  of dial  102 , which also includes a raised ridge  120 . The ridge  120  is circular and concentric with the perimeter wall  112 .  FIG. 3B  shows a closeup of the ridge  120  that includes a slot  122 , which serves as a recess for a pilot valve  172  (shown in  FIG. 6 ) when the dial  102  is in the off (CERRADO) position. Ridge  120  also has a notch  124  separated from slot  122  by a ramp  126 . The notch  124  serves as a recess for the pilot valve  172  when the dial is in the pilot (PILOTO) position. Along the ramp  126 , the height of ridge  120 , relative to a back side surface  128 , increases from a first height at slot  122  to a second greater height at notch  124 . It is along the ramp  126 , from slot  122  to notch  124 , that the pilot valve  172  transitions from a closed position (i.e., no gas flow to pilot line  113 ) to an open position (i.e., gas flows to pilot line  113 ). 
       FIG. 4  illustrates a view of the valve body  104  that shows an interior portion  125  having a safety magnet port  130 , a pilot valve port  132 , and an outlet port  134 . The valve body  104  further includes an inlet  136  located at a perimeter wall  138  of the valve body  104 . An outlet  140  is also located at the perimeter wall  138 . In one embodiment, the outlet  140  is spaced along the perimeter wall  138  roughly 90 degrees apart from the inlet  136 . In an alternate embodiment, inlet  136  is spaced roughly 180 degrees apart from the outlet  140 . 
     In the embodiment shown in  FIG. 4 , the inlet  136  provides an opening that puts the interior portion  125  of valve body  104  in fluid communication with an exterior gas supply (not shown) configured to connect to the inlet  136 . Safety magnet port  130  is located adjacent to the inlet  136 . Pilot valve port  132  connects the interior portion  125  to the pilot line  113 . Outlet port  134  connects the interior portion  125  to the outlet  140 . The interior portion  125  also includes a plurality of openings  142  for attaching a valve cover  144  to the interior portion  125  of the valve body  104 . The valve cover  144  is configured to contain gas from the inlet  136  as it flows to the outlet  140  and the pilot line  113 . An opening  148  in the valve body  104  is for a temperature adjustment screw  154  (shown in  FIG. 5 ), which is configured to pass through the opening  148  such that part of temperature adjustment screw  154  resides in the interior portion  125  and part resides in an interior space  135  opposite the interior portion  125 . 
       FIG. 5  illustrates a cross-sectional view of a gas valve assembly  100  according to an embodiment of the invention. In this embodiment, the dial  102  is attached to the valve body  104  by a screw  152  that threads into an opening in the valve cover  144  through a center opening in the dial  102 . At one end, the temperature adjustment screw  154  includes a gear  156  configured to engage the gear  114  on the dial  102 . The temperature adjustment screw  154  is threaded into the opening  148  on the valve body  104 , and is partly disposed in the interior portion  125  and partly disposed in interior space  135 . At the end of the temperature adjustment screw  154  opposite the gear  156 , the temperature adjustment screw  154  has a tip  178 , in interior space  135 , that contacts a lever  158 . In interior space  135 , the lever  158  also contacts an invar rod  160  that is part of a temperature probe assembly  162  that also includes a copper tube  161 . On a side of the lever  158  opposite the invar rod  160 , the lever  158  contacts a diaphragm  164  configured to regulate a gas flow from the interior portion  125  to the outlet  140 . The diaphragm  164  is coupled to a seal  165  that controls the flow of gas though the outlet port  134  to the outlet  140 . The temperature probe assembly  162 , including the invar rod  160 , is supported by the shank  106 , which is removably attached to the valve body  104  by screws or other suitable means. 
       FIG. 6  illustrates a cross-sectional view of a gas valve assembly  100  according to an embodiment of the invention. The gas valve  100  includes a pilot valve  172 , and a spring  174 , which biases the pilot valve  172  toward the closed position (i.e., no gas flow to the pilot line  113 ). The valve body  104  further includes a passageway  176  through which gas may flow from the pilot valve port  132  to the pilot line  113  when the pilot valve is in the open position (shown in  FIG. 7 ). 
     When the dial  102  is rotated to the off (CERRADO) position (i.e., the marking  110  above CERRADO is aligned with fixed reference  111 ), the tip  178  of the pilot valve  172  drops into the slot  122  (shown in  FIG. 3B ) in ridge  120  (shown in  FIG. 3B ) on the back side  115  of dial  102 . When the tip  178  of the pilot valve  172  drops into the slot  122 , the pilot valve  172  seals against the passageway  176 , thus preventing the flow of gas to the pilot line  113 . The pilot valve  172  is held in the slot  122  by the force of the spring  174 . When the pilot valve  172  is closed, there is no pilot flame, and the safety magnet  182  (shown in  FIG. 8 ) is not energized, and gas flow to the pilot line  113  and the outlet  140  is blocked. 
     To ignite the pilot flame, the dial  102  is rotated until the marking  110  above the label PILOTO (pilot) is aligned with the fixed reference  111 . As the dial  102  is rotated, the pilot valve  172  moves from slot  122  along ramp  126  to notch  124 . As the pilot valve  172  moves along the ramp  126 , the pilot valve  172  moves against the spring  174  toward the shank  106 , such that the pilot valve  172  no longer seals the passageway  176 .  FIG. 7  illustrates a cross-sectional view of the gas valve assembly  100  that shows the position of the pilot valve  172  when the dial  102  is rotated to PILOTO. When the dial  102  is in this position, there is a gas flow path from the passageway  176  to the pilot line  113 . 
     Even though rotating the dial  102  to PILOTO creates a gas flow path from the pilot valve port  132  to the pilot line  113 , gas from the inlet  136  does not immediately flow to the pilot line  113 .  FIG. 8  illustrates a cross-sectional view of gas valve assembly  100 , wherein, at the PILOTO position, a stem  188  attached to the reset button  107  in dial  102  is aligned with the safety magnet  182  and the magnet energizing shaft  184 . The safety magnet  182  is disposed within the valve body  104 , while the magnet energizing shaft  184  is disposed within the valve cover  144 . Until the pilot flame is ignited, the safety magnet  182  remains in a closed position, which seals the safety magnet port  130  preventing gas flow into the pilot line  113  or into the outlet  140 . A spring  186  biases the safety magnet  182  towards this closed position. A spring  190  biases the magnet energizing shaft  184  toward the stem  188  and away from the safety magnet  182 . 
     When igniting the pilot flame, the reset button  107  is depressed, causing the stem  188  on the reset button  107  to push against the magnet energizing shaft  184 , which, in turn, pushes against the safety magnet  182  causing it to unseal the safety magnet port  130 . Moving the safety magnet  182  away from safety magnet port  130  allows gas from the inlet  136  to flow into the valve body  104  and to the pilot line  113  thereby allowing ignition of the pilot flame. The pilot flame heats the thermocouple  117 , which generates an electrical current therein. A wire  192  provides a conductive path for the electrical current from the thermocouple  117  to the safety magnet  182 . The electrical current energizes the safety magnet  182  causing it to move against the force of the spring  186  and away from the safety magnet port  130 . In this manner, as long as the pilot flame burns, the safety magnet  182  will remain energized in the open position allowing gas from the inlet  136  to flow to the pilot valve port  132  and to the outlet port  134 . 
     In addition to eliminating the need for the gas cock found on conventional gas valves, the gas valve assembly  100  also includes a safety feature, wherein the pilot valve  172  is configured to shut off the flow of gas to the pilot line  113 , and therefore to the outlet  140  when the dial  102  is melted or destroyed by fire. In such a circumstance, a main burner of a water heater (not shown) would be shut off until the fire is extinguished. In normal operation, the pilot valve  172  is held in the open position by the ridge  120  on the back side  115  of dial  102 . When the dial  102  is made of plastic, a fire in the vicinity of the gas valve  100  could cause the dial  102  to melt. In such an event, the ridge  120  would cease to hold the pilot valve  172  in the open position. The biasing spring  174  would cause the pilot valve  172  to close extinguishing the pilot flame, which would de-energize the safety magnet  182 , thereby shutting off the flow of gas to the outlet  140  and to the main burner of the water heater. In this manner, the flow of gas to the water heater is prevented until the fire is extinguished and safe operating conditions are restored. 
     When the dial  102  is rotated to one of the temperature settings, the pilot valve  172  remains essentially unchanged in the open position, thus permitting gas flow to the pilot line  113 . Referring to  FIG. 5 , it can be seen that the rotation of dial  102  also rotates the temperature adjustment screw  154  via gear  156  and gear  114  on the dial  102 . When the dial  102  is rotated from PILOTO to the first temperature setting, FRIO, the temperature adjustment screw  154  rotates such that it threads into opening  148  causing the tip  178  to push against the lever  158 . As a result, the end of the lever  158  contacting the tip  178  moves toward the shank  106 . The lever  158  is configured to pivot such that as the end contacting the tip  178  moves toward the shank  106 , the end of the lever  158  contacting the invar rod  160  moves away from the shank  106  and toward the diaphragm  164 . 
     Depending on the temperature calibration of the temperature probe assembly  162 , at some threshold temperature, for example 60 degrees Fahrenheit, when the temperature of the water in the water tank falls below the threshold temperature, the copper tube  161  in the temperature probe assembly  162  contracts causing the invar rod  160  to push against the lever  158 , which, in turn, pushes against the diaphragm  164  causing the diaphragm  164  to collapse. The collapsing diaphragm  164  causes the seal  165  to move away from the outlet port  134 , thus allowing gas to flow from the inlet  136  through the outlet port  134  to the outlet  140  and to the main burner for the water heater (not shown). 
     When the dial  102  is rotated to the second temperature setting, TIBIO, the temperature adjustment screw  154  is threaded further into the opening  148  causing the tip  178  to move one end of the lever closer to the shank  106 , while causing the end contacting the invar rod  160  to move more toward the diaphragm  164 . In this example, as a result of this movement of the lever  158  toward the diaphragm  164 , the invar rod  160  does not have to move as much as in the previous example to cause the diaphragm  164  to collapse. Accordingly, the threshold temperature of the water in the tank does not have to drop as low as the 60 degrees Fahrenheit in the previous example to cause the diaphragm  164  to collapse and allow gas to flow from the outlet port  134  to the outlet  140  and to the main burner. For example, the threshold water temperature for the TIBIO setting may be 90 degrees Fahrenheit. 
     In the same manner, rotating the dial  102  to the third temperature setting, CALIENTE, may raise the threshold temperature, for example, to 120 degrees Fahrenheit. At this temperature setting, when the water temperature falls below 120 degrees Fahrenheit, the movement of the invar rod  160  pushes against the lever  158  collapsing the diaphragm  164  and allowing gas to flow to the main burner. 
       FIGS. 9-15  illustrate the aesthetic properties of the new, original, and ornamental design for the gas valve assembly. 
       FIG. 16  illustrates a gas-fired water heater  200  that incorporates an embodiment of the invention. It should be noted that the water heater  200  shown in  FIG. 16  is an example storage-type gas water heater incorporating aspects of the invention and that other constructions for a gas water heating system are possible. The water heater  200  includes a cylindrical storage tank  202  for storing the water to be heated by a burner  204  within a combustion chamber  205  located at the bottom of the water heater  200  along with a flue  206 , which provides a means for evacuation of burner gases. The housing  208  around the storage tank  202  is typically in the form of an insulated round jacket to prevent heat loss though the exterior surface of the tank  202 . The heat from the burner  204  is exchanged with the water in the storage tank  202  via the flue pipe  206  that leads from the burner  204  through the storage tank  202  to an outlet  212  located on the top of the hot water heater  100 . The water heater  200  includes a base pan  214  supporting the water tank  202  and housing  208 . A cold water inlet tube  216  and a hot water outlet tube  218  extend through a top wall  220  of the water tank  202 . 
     The gas valve  100  of  FIG. 1  is attached to the storage tank  202 , and as explained above, the dial  102  (shown in  FIG. 2 ) can perform the functions of the gas cock on a conventional gas valve, namely to prevent gas from flowing to the water heater  200  or permit gas to flow to the water heater  200  to establish a safe pilot flame for burner  204  ignition. The gas valve  100  includes a thermocouple  117  (shown in  FIG. 8 ) to sense the presence of the pilot flame, and energize the safety magnet to permit gas to flow the burner  204 . As discussed above, the dial  102  can also select the temperature setting for water in the storage tank  202 . The temperature probe assembly  162  (shown in  FIG. 5 ) is assembled into an opening in the storage tank  202 . The temperature probe assembly  162  is calibrated in accordance with the temperature settings on the dial  102 . When the temperature of the water in the storage tank  202  drops below a threshold temperature corresponding to the selected temperature setting, the gas valve supplies gas to light the pilot light and operate the burner  208  to heat the water in the tank  202 . 
     All references, including publications, patent applications, and patents cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein. 
     The use of the terms “a” and “an” and “the” and similar referents in the context of describing the invention (especially in the context of the following claims) is to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms “comprising,” “having,” “including,” and “containing” are to be construed as open-ended terms (i.e., meaning “including, but not limited to,”) unless otherwise noted. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention. 
     Preferred embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention. Variations of those preferred embodiments may become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventors expect skilled artisans to employ such variations as appropriate, and the inventors intend for the invention to be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context.