Abstract:
A gas flow modulator for gas appliances has electronic control to regulate the flow of gas by means of a control mechanism. The control mechanism is situated transversely to the flow of gas. The control mechanism also includes features to insure a minimal flow of gas and a maximum flow of gas as selectable by a potentiometer.

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
       [0001]    This is a regular utility application of and claims priority to U.S. Provisional Application No. 61/646,805, filed on May 14, 2012, the contents of which are expressly incorporated herein by reference. 
     
    
     FIELD OF ART 
       [0002]    The present disclosure is directed to an apparatus, systems, and methods for modulating gas flow. More particularly, the present disclosure describes an apparatus, systems, and methods for controlling the flow of combustible gas for commercial, residential and recreation heating applications. 
       BACKGROUND 
       [0003]    In the design and manufacture of gas appliances such as furnaces, water heaters, fireplaces and other such appliances, it is often desirable to be able to regulate the flow of a gas supply to a burner or other ignition source. By regulating the gas flow, the desired operating parameter of the appliance can be regulated, e.g. water temperature, heat output, etc. 
         [0004]    Binary gas flow restrictors have the limitation that either the gas is on or off. Thus, dynamic temperature control results in unwanted temperature extremes at the heat exchanger or burner. Mechanically adjustable valves lack the automated adjustability and/or programmability of electrically controlled systems. Electrically controlled valves may also have limitations in size, complexity and therefore costs, and orientation of the control mechanism relative to the fuel flow path. 
       SUMMARY 
       [0005]    One embodiment of the present disclosure includes a system for modulating gas flow. The system includes a fuel supply, a regulator coupled to the fuel supply; a gas flow valve, the gas flow valve having a valve body having a fuel flow path, a control aperture, and a control mechanism partially disposed within the control aperture. The control mechanism has a shaft and a sleeve disposed and movable within the shaft and in communication with the fuel flow path. The system also includes a burner coupled to the gas flow valve. The control mechanism is disposed transversely to the fuel flow path. 
         [0006]    Another aspect of the present disclosure includes a gas flow modulator. The gas flow modulator has a gas flow modulator valve. The gas flow modulator valve includes a valve body having a fuel flow path and a control aperture. The gas flow modulator valve further includes a control mechanism partially disposed within the control aperture. The control mechanism has a shaft and a sleeve disposed and movable within the shaft and in communication with the fuel flow path. The control mechanism is disposed transversely to the fuel flow path. 
         [0007]    A method for modulating gas flow is described within the present disclosure. The method provides for a gas flow modulator valve having a fuel flow path defined by a gas inlet, a gas outlet. and a control aperture. The method partially disposes a control mechanism in the control aperture. The control mechanism has a shaft and a sleeve disposed and movable within the shaft and in communication with the fuel flow path. The control mechanism is disposed transversely to the fuel flow path. The method further contemplates coupling a potentiometer to the modulator valve, coupling the gas inlet to a gas supply; and coupling the gas outlet to a gas appliance. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]    These and other features and advantages of the present device, systems, and methods will become appreciated as the same become better understood with reference to the specification, claims and appended drawings wherein: 
           [0009]      FIG. 1  illustrates a system level block diagram in accordance with one embodiment of the present disclosure; 
           [0010]      FIG. 2  illustrates a perspective view of a gas flow modulator according to one embodiment of the present disclosure; 
           [0011]      FIG. 3  illustrates an exploded view of the various components of the gas flow modulator of  FIG. 2 ; 
           [0012]      FIG. 4  illustrates a cross section view of a gas flow modulator according to one embodiment of the present disclosure; and 
           [0013]      FIG. 5  illustrates another cross section view of a gas flow modulator according to one embodiment of the present disclosure. 
       
    
    
     DETAILED DESCRIPTION 
       [0014]    The detailed description set forth below in connection with the appended drawings is intended as a description of the presently preferred embodiments of a gas flow modulator provided in accordance with aspects of the present device, system, and method and is not intended to represent the only forms in which the present device, system, and method may be constructed or utilized. The description sets forth the features and the steps for constructing and using the embodiments of the present device, system, and method in connection with the illustrated embodiments. It is to be understood, however, that the same or equivalent functions and structures may be accomplished by different embodiments that are also intended to be encompassed within the spirit and scope of the present disclosure. As denoted elsewhere herein, like reference numerals are intended to indicate like or similar elements or features. 
         [0015]      FIG. 1  is a system level block diagram showing a gas system  100  in accordance with an embodiment of the present disclosure. As shown, a gas supply  101  is connected to a burner  105  for supplying fuel to the burner. The gas supply  101  may be any type of combustible gas fuel, such as natural gas or propane. In the present embodiment, the gas supply  101  is contemplated as liquid propane (LP). The liquid propane may be stored in one or more tanks. Each tank may have a specific capacity. For example, conventional LP tanks for personal, residential and/or recreational use may have a capacity of  5  gallons. However, other size tanks, including tanks for commercial purposes, are contemplated and are within the scope of this disclosure. 
         [0016]    The gas system  101  includes a regulator  103 . In the present embodiment, the regulator  103  causes the liquid propane stored in the tank  101  to change from a liquid state to a gaseous state due to pressure drop across the regulator so that the gas may be combusted by an appliance such as a water heater, furnace, gas fireplace or other type of gas appliance. The regulator may also include a shut off valve (shown schematically by reference numeral  103  and typically a separate valve body apart from the regulator  103 ). In the event that there is a gas leak in the system, or for any other user requirement, the shut off valve stops the flow of gas from the gas supply  101 . Thus, the shut off valve serves to isolate the gas supply  101  from the remainder of the system  100 . 
         [0017]    In another embodiment, a failed close solenoid valve (not shown) is located immediately downstream of the regulator  103 . i.e., further away from the gas source. In the event of an electrical or power failure, the failed close solenoid valve closes the gas line  120  to the burner  105 . The failed close solenoid valve is either fully opened when powered or fully closed when power is lost. 
         [0018]    In the present embodiment, a gas flow modulator  200  includes a potentiometer (P)  201  or other type of electrical/electronic control, a controller  202  and a modulator valve  203 . The modulator valve  203  is coupled to the regulator  103  and to the controller  202 . The controller is also coupled to the potentiometer  201 . The modulator valve  203  serves to control the volume of gas, i.e. the fuel flow, distributed to the burner  105 . The function and components comprising the modulator valve  203  are more fully described below. 
         [0019]    In one example, the potentiometer  201  is a linear potentiometer, a membrane potentiometer, a single-turn potentiometer, or a multi-turn potentiometer. An output of the potentiometer  201  is connected to the controller  202 . The controller  202  receives input from the potentiometer  201  and provides the operating output voltage range for proper operation of the modulator valve  203 , such as in the range of 3-9 volts to modulate the magnetic flux of the solenoid, as further discussed below. The controller  202  may also include a time delay circuit, thereby allowing for a delay in outputting signals to the modulator valve  203  to delay restricting the flow of gas to the burner  105 . That is, during the time delay period, there is no power distributed to the modulator valve  203 . Without power, the modulator valve  203  is in a full open state with maximum gas flow, as further described below in reference to  FIG. 5 . The full open state facilitates proper lighting of the burner  105 . The controller  202  may also be coupled to a feedback loop from, for example a water temperature sensor, so as to maintain a constant water temperature by adjusting gas flow, via modulating the valve  203 , in real time. Feedback loops having other parameters between the controller  202  and the appliance are also contemplated as being within the scope of the disclosure. 
         [0020]    Also illustrated in  FIG. 1  is a burner  105 , which can embody any number of prior art burners, with or without manual flow control or regulator for modulating flow to the burner. The burner  105  receives the gas flow from the gas supply through the modulator valve  203  and combusts the gas to produce heat. The burner  105  may be connected to or part of a gas appliance such as a hot water heater or other gas appliance. The burner  105  may also include a pilot light. The pilot light serves as an ignition source to ignite the burner  105  when the flow of gas is turned on. The pilot light uses a relative small volume of gas and is therefore left burning continuously as long as the gas supply is connected and available. Alternatively, a spark or electronic igniter may be incorporated at the burner for providing the needed spark to light the fire. 
         [0021]    Referring to  FIG. 2 , a perspective view of the modulator valve  203  is illustrated comprising a solenoid  125  and a valve body  209 . Terminals  205  are provided on the solenoid body  127 . The terminals are electrical contacts that connect the modulator valve  203  to the potentiometer  201  by one or more wires (shown schematically in  FIG. 1 ). The terminals  205  are also connected to coil or coil windings  207  located inside the solenoid body  127 . The coil  207  acts as an electro-magnet to move a shaft located therein and its function as part of a control mechanism is more fully described below. By varying internal resistance, the potentiometer  201  controls the voltage potential and current to the coil  207  to change the magnetic flux produced by the coil and hence the amount of travel of the shaft against a spring force, as further discussed below. 
         [0022]    A modulator valve body  209  is coupled to the solenoid  125 . The modulator valve body  209  is formed from a metallic material. In one example, the metallic material is non-corrosive and non-magnetic material, such as brass. In another example, the valve body is formed from engineered plastic, such as polyetheretherketone (PEEK). The valve body  209  has a basic “T” shape having a horizontal member and a vertical member although other body configurations are contemplated. The horizontal member includes a gas inlet  211  disposed on one end and a gas outlet  213  disposed on an opposite end. The vertical member, which is substantially perpendicular to the horizontal member, has a control aperture  215  (shown in  FIG. 3 ). Although described as having a “T” shape with horizontal and vertical members, in the present embodiment the valve body  209  is an integral structure fabricated from a homogeneous material. 
         [0023]    The gas inlet  211  and gas outlet  213  provide a fuel flow path for the gas as it passes through the modulator valve body  209 . The gas inlet  211  and gas outlet  213  may have threaded apertures, female threads, for threadedly connecting with gas lines. Alternatively, the gas inlet  211  and gas outlet  213  may be protrusions such as male nipples having threads circumferentially around the exterior of the nipples (not shown. i.e., male threads). The transverse coupling of the modulator valve body  209  to the solenoid  125  allows for the gas to flow laterally through the modulator valve body  209 , while the solenoid  125  and thus the control mechanism  217  (see  FIG. 3 ) is coupled longitudinally to the modulator valve body  209 . That is, the control mechanism  217  is transverse, e.g. substantially orthogonal, to the flow of gas. 
         [0024]    An exploded or disassembled view of the gas flow modulator  203  is illustrated in  FIG. 3 . The control mechanism  217  of the solenoid  125  is comprised of the coil or coil windings  207  located inside the solenoid body  157 , a shaft  219 , a magnet  221  located at one end of an elongated sleeve  223 , a spring  225  located at a second end of the elongated sleeve  225 , and a spring pin  227  having a pin portion  227   a  that is inserted into an inner circumference of the spring  225  and a base portion  227   b.  In one example, the base portion  227   b  is inserted into an inner circumference of the shaft  219 . In another example, the base portion is positioned in the valve body but externally of the shaft. When inserted, a lower surface of the base portion  227   b  is substantially coplanar with a lower surface of a lower opening of the shaft  219 . The sleeve  223  and spring pin  227  may be formed from a plastic material or other non-magnetic, non-corrosive materials. 
         [0025]    The magnet  221  is disposed in an upper portion of the hollow cylinder sleeve  223 , which may be referred to as a first end of the sleeve. In one example, the magnet  221  is pressed fit into the sleeve  223 . In another example, the magnet is bonded or glued to the first end of the sleeve. The spring  225  and the spring pin  227  are inserted into a lower portion of the hollow cylinder sleeve  223 . The magnet  221  and the spring  225  may be separated by a partition  129  formed internally of the sleeve  223 . In one example, the partition  129  is located half-way between the first end and the second end of the sleeve  223 . In another example, the partition is located closer to the first end than the second end of the sleeve to provide greater volume or space for the compartment with the spring, such as to provide more spring space for spring travel and compression. Alternatively, the magnet  221  maybe pressed fit into the sleeve and the spring  225  may contact a lower surface of the magnet  221  without the partition  129 . The sleeve  223  is disposed internal to the shaft  219 . The shaft  219  and sleeve  223  assembly (i.e. magnet  221 , spring  225  and spring pin  227 , or at least portions thereof) are coupled to the modulator valve body by a set screw  229 . A lower portion of the shaft  219  is inserted into the control aperture  215  of the valve body. Thus, the control mechanism  217  is partially inserted into the valve body  209  via the control aperture  215 . 
         [0026]    The shaft  219  may be a two-tiered cylindrical, homogeneous, integral structure. The shaft  219  may be formed from a non-corrosive, non-magnetic material such as brass. The two tiers may be homogeneous in material. The two tiers may also be integral in that they may be forged or cast simultaneously. In alternative embodiments, the two tiers may be neither homogeneous nor integral, i.e. two separate components formed separately from different materials and coupled together. 
         [0027]    The two tiers include an upper tier  219   a  having an outer circumference and a cylindrical hollow interior and a lower tier  219   b  having an outer circumference, which is greater than the outer circumference of the upper tier  219   a.  The lower tier  219   b  also has a cylindrical hollow interior which has a circumference that is substantially the same as the cylindrical hollow interior of the upper tier  219   a.  Thus, as shown, it is understood that the shaft comprises an first section having a first outer diameter and a second section having a second outer diameter that is greater than the first diameter, and wherein the shaft comprises an inner bore having a generally constant inside diameter. 
         [0028]    The shaft  219  has several other features which are illustrated in the present embodiment. Located on the upper tier  219   a  is an annular recess  231  that permits the shaft  219  to be connected to the coil  207  by a retainer ring  233 . That is, the shaft  219  is inserted into the solenoid body  127  until the first tier section projects through an opening  207   a  in the solenoid body  127  and the retainer ring  233  is fitted into the annular recess  231  to secure the shaft  219  to the solenoid body  127 . In another example, a threaded cap or nut is threaded to the first end of the shaft that projects out the opening  207   a.    
         [0029]    The lower tier  219   b  of the shaft  219  has a number of openings. A first set of openings includes two circular openings  235  of the same size (i.e. same radius) which are diametrically opposed to each other across the cylindrical hollow interior of the lower tier  219   b  of the shaft  219 . A second set of openings includes two circular openings  237  also of the same size (i.e. same radius) which are also diametrically opposed to each other across the cylindrical hollow interior of the lower tier  219   h  of the shaft  219 . In the present embodiment, the radius of the second set of openings is substantially smaller than the radius of the first set of openings. Preferably the first set of openings  235  is located further away from the open end of the lower tier  219   b  than the second set of openings  237 . In an alternative embodiment, each set of openings can have more than two holes or more than two circular openings. In still yet another embodiment, only the first set of openings  235  can have more than two circular openings. Although the openings of each set are of the same size, they can vary and can have a different configuration than circular, such as oval or star shape. 
         [0030]    The lower tier  219   b  of the shaft  219  also includes an O-ring  239  located exteriorly of the shaft  219  and which may be partially recessed, such as by incorporating an annular groove for receiving the O-ring. The O-ring  239  provides a seal against the interior surface of the valve body when the shaft  219  is inserted into the modulator valve body  209  such that when gas flows through the modulator valve body  209 , leaks are avoided or prevented. Also, the lower tier  219   b  of the shaft  219  may include a threaded bore  241  for receiving the set screw  229 . In some embodiments the threaded bore  241  may be threaded to match the threads of the set screw  229 . 
         [0031]    The operation of the gas flow modulator valve  203  can best be appreciated by referring to  FIGS. 4 and 5 .  FIG. 4  is a cross sectional view of one embodiment of the present disclosure illustrating the position of the valve  203  for minimum gas flow. Note that the two diametrically opposed sets of openings include the upper set  235  and the lower set  237  and that the upper set of openings  235  are substantially larger than the lower set of openings  237 . In one example, at least one of the circular openings of the upper set of openings is at least 30% larger than the lower set of openings. In another example, at least one of the circular openings of the upper set of openings is at least 200% larger than the lower set of openings. Preferably, at least one of the circular openings of the upper set of openings is at least 300% larger to about 600% larger than the lower set of openings with larger sizes contemplated. In embodiment shown, the upper set of openings  235 , when modulated, provides for gas flow through the valve  203  to the burner  105  ( FIG. 1 ) for operation of the appliance, such as a stove, a water tank, or other fuel consuming equipment. The circular openings of the first set or upper set of openings  235  may be wide open to permit maximum flow through the valve body, closed or occluded to restrict flow or block flow through the upper set of openings  235 , or modulated to permit partial flow somewhere in between. The second set or lower set of openings  237 , because they are not blocked or closed by the sleeve  223  even in the minimum gas flow condition, only allows for a small volume of gas there across to maintain the pilot light at the burner  105  and/or to maintain a low flame at the burner. 
         [0032]    As shown in the minimum gas flow condition of  FIG. 4 , the spring  225  is compressed by the electro-magnetic force applied from the coil  207  as determined by the position of the potentiometer ( FIG. 1 ), which forces the sleeve  223  downward. A lateral surface of the sleeve, such as the sleeve body, obstructs, blocks or otherwise restricts the flow of gas through the upper set of openings  235 . However, because of the length of the pin portion  227   a  relative to the position of the magnet  221  in the sleeve  223  (or a partition internal to the sleeve  223  which separates the magnet  221  from the spring  225 ), the sleeve is prevented from blocking or restricting the flow of gas through the lower set of openings  237 . Thus, even in the fully energized position shown in  FIG. 4 , when the potentiometer  201  is set for minimal gas flow, a minimal flow of gas to maintain the pilot light or for other considerations is preserved. 
         [0033]    Thus, as shown, the modulator valve  203  is understood to include a valve body  209  comprising an inlet  211 , an outlet  213 , and an intermediate opening  215  in communication with a body bore  215  having a bore bottom. A shaft  219  comprising an elongated body having at least one end opening, a hollow core, a first set of openings  235  each with an opening dimension, and a second set of openings  237  each with an opening dimension positioned in the body bore of the valve body. A sleeve  223  comprising a magnet  221  concentrically positioned and axially movable relative to the shaft is positioned at least partially within the shaft. A spring  225  is provided in the shaft for biasing the sleeve away from the bore bottom of the body bore. A solenoid  125  comprising coil windings is coupled to the valve body for moving the magnet towards the bore bottom when actuated. In a particular example, a spring pin  227  is positioned inside a central space of the spring. The spring pin comprises a pin portion  227   a  and a base portion  227   b.  The pin portion  227   a  has a length and an end in contact with a partition surface inside the bore of the sleeve or a contact end surface of the magnet. In an example, the length of the pin portion  227   a  is longer than a distance between the partition surface and the end most surface  131  of the sleeve  131  ( FIG. 4 ) or longer than a distance between the contact end of the magnet and the end most surface of the sleeve  131  so that the portion of the sleeve below the partition surface or below the contact surface of the magnet does not completely cover the pin portion  227   a.  This allows the lower or second set of openings  237  to be free from obstructions to permit minimal gas flow through the valve. In an alternative embodiment, the sleeve is longer, or the spring pin stem  227   a  is shorter, so that the end  131  of the sleeve  223  contacts the base  227   b  of the spring pin  227  in the minimum flow position. However, the sleeve  223  incorporates a corresponding set of openings (not shown) that align with the lower openings  237  on the shaft  219  to permit flow through the shaft and the corresponding openings on the sleeve. 
         [0034]    In still yet another example, the locations of the minimum flow openings  237  and the large flow openings  237  may be reversed, with the minimum flow openings  237  located above the large flow openings  235 . In this alternative embodiment, the sleeve incorporates a corresponding set of openings as the re-arranged minimum flow openings. 
         [0035]    Referring to  FIG. 5 , operation of the gas modulator valve  203  for maximum gas flow is illustrated. In this embodiment, the electro-magnetic force is minimized, removed, or turned off from the coil  207 . In the absence of the electro-magnetic force, the spring  225  expands to push the sleeve  223  upwards towards the retainer ring  233  thus revealing the upper set of openings  235  (as well as the lower set of openings  237 ) and allowing the maximum volume of gas to pass through the valve body  209 . Note that when power is lost to the gas flow modulator  200  (i.e. to the potentiometer  201  and the coil  207 , See  FIGS. 1-3 ), this has the effect of removing the electro-magnetic force and the gas modulator valve  203  reverts to the open or maximum flow state. Also, if the regulator  103  shut off valve is closed (see  FIG. 1 ) and the gas modulator valve is placed in the maximum gas flow state, any trapped gas in the system  100  will vacate the system and insure that there is no pent up gas pressure in the lines that may otherwise cause a safety hazard. 
         [0036]    With reference again to  FIG. 4 , the shaft  219  has a bore  148  comprising a bore bottom  150  for receiving the sleeve  223 , as previously discussed. The gap  152  between the upper end  133  of the sleeve  223  and the bore bottom  150  of the shaft  219  represents the maximum range of travel for the sleeve within the bore  148 . Thus, depending on the position of the potentiometer P ( FIG. 1 ), the upper end  133  of the sleeve can rise a small amount to a maximum amount, represented by the upper end  133  abutting or contacting the bore bottom  150 , as shown in  FIG. 5  and depending on the length and size of the spring  225 . 
         [0037]    Thus, as described, the modulator valve  203  is understood to include a valve body  209  comprising an inlet  211 , an outlet  213 , and an intermediate opening  215  in communication with a body bore  215  having a bore bottom. A shaft  219  comprising an elongated body having at least one end opening, a hollow core, a first set of openings  235  and a second set of openings  237  positioned in the body bore of the valve body. A sleeve  223  comprising a magnet  221  concentrically positioned and axially movable relative to the shaft is positioned at least partially within the shaft. A spring  225  is provided in the shaft for biasing the sleeve away from the bore bottom of the body bore. A solenoid  125  comprising coil windings is coupled to the valve body for moving the magnet towards the bore bottom when actuated. When the potentiometer is rotated, the solenoid reacts and changes the magnetic flux inside the valve, which allows the spring to move from a fully compressed position to a less compressed position. Thus, in the present valve embodiment, it is the sleeve that moves and not the shaft to control the amount of gas flow through the valve. In a particular example, the shaft is secured to the solenoid by a mechanical fastening device, such as a clip. 
         [0038]    In a particular example, a spring pin  227  is positioned inside a central space of the spring. The spring pin comprises a pin portion  227   a  and a base portion  227   b.  The pin portion  227   a  has a length and an end in contact with a partition surface inside the bore of the sleeve or a contact end surface of the magnet. In an example, the length of the pin portion  227   a  is longer than a distance between the partition surface and the end most surface  131  of the sleeve  131  ( FIG. 4 ) or longer than a distance between the contact end of the magnet and the end most surface of the sleeve  131  so that the portion of the sleeve below the partition surface or below the contact surface of the magnet does not completely cover the pin portion  227   a.    
         [0039]    Although limited embodiments of the gas flow modulator assemblies and their components have been specifically described and illustrated herein, many modifications and variations will be apparent to those skilled in the art. Accordingly, it is to be understood that the gas flow modulator assemblies and their components constructed according to principles of the disclosed device, system, and method may be embodied other than as specifically described herein. The disclosure is also defined in the following claims.