Patent Document

TECHNICAL FIELD 
     The disclosure relates generally to sensor assemblies, and more particularly, to sensor assemblies for mounting non-immersion type temperature sensor relative to a tank. 
     BACKGROUND 
     It is often desirable to obtain a measure of the temperature of a fluid (e.g. a liquid or gas) inside of an enclosed tank, such as a water heater tank. While water heaters are described below as one example application, it should be recognized that there are many other applications where it may be desirable to obtain a measure of the temperature of a fluid inside of an enclosed tank. For example, in some industrial applications, it may be desirable to obtain a measure of the temperature of a fluid passing through a supply pipe that is supplying a constituent to an industrial process. In another example, in a food processing application, it may be desirable to obtain a measure of the temperature of a fluid that is in a distilling tower or a fermenting vat. These are just some examples. 
     Water heaters are used in homes, businesses and just about any establishment having the need for heated water. A conventional water heater typically has at least one heating element or “heater,” such as a gas-fired and/or electric burner. Each water heater also typically has at least one thermostat or controller for controlling the heater. The controller typically receives signals related to the temperature of the water within the water heater tank, often from a temperature sensor that is thermally engaged with the water in the water heater tank. 
     In some instances, a water heater may operate in accordance with a first temperature set point and a second temperature set point. The difference between the first and second temperature set point may be referred to as the temperature differential of the water heater. When temperature signals from the temperature sensor indicate that the water temperature is below the first set point, for example when the water temperature is below about 120° F., the controller may turn on the heater and the water within the water heater tank begins to heat. After some time, the water temperature within the water heater tank will increase to the second set point, which, for example may be about 140° F. At this point, the controller may cause the heater to reduce its heat output or, alternatively, causes the heater to turn off. This heat cycle begins again when the water temperature within the water heater tank cools down below the first set point. 
     For a gas fired water heater, a temperature sensor, a gas valve and a controller are often mounted relative to the water heater tank. The controller typically receives a temperature signal from the temperature sensor. In some cases, the temperature sensor may protrude into and is thermally coupled to the water in the water heater tank. The controller typically is programmed to control the gas valve such that the temperature of the water in the water heater tank remains between the first and second temperature set points, as described above. For an electric water heater, a temperature sensor, a power delivery unit and a controller may be mounted to the water heater tank. In this case, the controller may control the power delivery unit such that the temperature of the water in the water heater tank is kept between the first and second temperature set points. 
     In some water heater applications, the temperature sensor may be an immersion-type sensor that, when installed, is immersed in the water to maximize conductive and convective heat transfer with the water in the water heater tank. Such placement of the temperature sensor provides direct contact with the water in the water heater tank, and consequently may provide a fairly accurate measure of water temperature. However, immersion-type sensors typically require a waterproof seal between the sensor and the water heater tank. Also, if the sensor fails and needs to be replaced, the water must typically be drained from the water heater tank. 
     In some applications, the temperature sensor may be a non-immersion-type sensor that is not immersed in the water of the water heater tank, but rather senses the water temperature from outside of the water heater tank, in some cases, a non-immersion-type temperature sensor may be placed adjacent to an outer wall of the water heater tank. In many cases, non-immersion type temperature sensors can be removed and replaced without draining the water from the water heater tank. However, non-immersion type temperature sensors often need to be placed relatively precisely with respect to the water heater tank in order to provide an accurate and/or reliable calculation of the water temperature inside of the water heater tank. What would be desirable is a device and method for more precisely mounting a non-immersion type temperature sensor relative to a tank, such as a water heater tank. 
     SUMMARY 
     The present disclosure relates generally to sensor assemblies, and more particularly, to sensor assemblies for mounting non-immersion type temperature sensor relative to a tank. While water heaters are described below as one example application, it should be recognized that there are many other applications where it may be desirable to obtain a measure of the temperature of a fluid inside of an enclosed tank. 
     An illustrative, but non-limiting example of the disclosure may be found in a sensor assembly for mounting a temperature sensor relative to a water heater tank. The sensor assembly may include a temperature sensor assembly that has a temperature sensor, a body configured to be secured relative to a water heater tank, and a biasing element situated between the body and the temperature sensor assembly. The biasing element may bias the temperature sensor assembly toward the water heater tank when the body is secured relative to the water heater tank. In some cases, the bias element may help the temperature sensor assume a proper position relative to the water heater tank, despite variations in equipment that may exist in the field. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
       The following description should be read with reference to the drawings. The drawings, which are not necessarily to scale, depict selected embodiments and are not intended to limit the scope of the disclosure. The disclosure may be more completely understood in consideration of the following detailed description of various embodiments in connection with the accompanying drawings, in which: 
         FIG. 1  is a schematic view of an illustrative but non-limiting water heater in accordance with the present disclosure; 
         FIG. 2  is a perspective view of an illustrative but non-limiting mounting bracket that may be used in conjunction with the water heater of  FIG. 1 ; 
         FIG. 3  is a cross-section of an illustrative but non-limiting mounting bracket and temperature sensor assembly engaging an illustrative water heater; and 
         FIG. 4  is a cross-section of another illustrative but non-limiting mounting bracket and temperature sensor assembly engaging an illustrative water heater. 
     
    
    
     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 the disclosure to the particular illustrative embodiments described. On the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the disclosure. 
     DESCRIPTION 
     The following description should be read with reference to the drawings, in which like elements in different drawings are numbered in like fashion. The drawings, which are not necessarily to scale, depict selected embodiments and are not intended to limit the scope of the disclosure. Although examples of construction, dimensions, and materials are illustrated for the various elements, those skilled in the art will recognize that many of the examples provided have suitable alternatives that may be utilized. 
     For the following defined terms, these definitions shall be applied, unless a different definition is given in the claims or elsewhere in this specification. 
     All numeric values are herein assumed to be modified by the term “about”, whether or not explicitly indicated. The term “about” generally refers to a range of numbers that one of skill in the art would consider equivalent to the recited value (i.e., having the same function or result). In many instances, the term “about” may be indicative as including numbers that are rounded to the nearest significant figure. 
     The recitation of numerical ranges by endpoints includes all numbers within that range (e.g., 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and 5). 
     Although some suitable dimensions ranges and/or values pertaining to various components, features and/or specifications are disclosed, one of skill in the art, incited by the present disclosure, would understand desired dimensions, ranges and/or values may deviate from those expressly disclosed. 
     It is often desirable to obtain a measure of the temperature of a fluid (e.g. a liquid or gas) inside of an enclosed tank, such as a water heater tank. While water heaters are described below as one example application, it should be recognized that there are many other applications where it may be desirable to obtain a measure of the temperature of a fluid inside of an enclosed tank. For example, in some industrial applications, it may be desirable to obtain a measure of the temperature of a fluid passing through a supply pipe that is supplying a constituent to an industrial process. In another example, in a food processing application, it may be desirable to obtain a measure of the temperature of a fluid that is in a distilling tower or a fermenting vat. These are just some examples. 
       FIG. 1  provides a schematic view of an illustrative but non-limiting water heater  10 . Water heater  10  includes a water heater tank  12 . The water heater tank  12  may include an insulating layer (not explicitly shown) positioned about the water heater tank  12  to help reduce thermal losses from the water heater tank  12 . Cold water enters water heater tank  12  through a cold water line  14  and is heated by a gas burner  24 . In some cases, the water heater  10  may include an electric heating element rather than a gas burner  24 . A power delivery unit (not shown) may be used to selectively apply power (i.e. current) to the electric heating element. In either case, the resulting heated water exits through a hot water line  16 . For gas-fired water heaters, a gas control unit  18 , such as a gas valve, regulates gas flow from a gas source  20  through a combustion gas line  22  and into gas burner  24 . A flue  26  permits combustion byproducts to safely exit. 
     As can be seen, water heater  10  may include a temperature sensor  28 . In some cases, temperature sensor  28  may enter water heater tank  12  at a location laterally offset from gas control unit  18 . In some instances, however, temperature sensor  28  may instead be located behind gas control unit  18 , and in some cases, may be supported and retained by a common mounting bracket such as that described more fully below. In some embodiments, a non-immersion type temperature sensor may be provided. While not explicitly shown, the water heater tank  12  may include a threaded spud  30  ( FIG. 3 ) or other feature(s) for mounting a non-immersion type temperature sensor  28  relative to the water heater tank  12 . 
       FIG. 2  is a perspective view of an illustrative but non-limiting mounting bracket  32  that may be used in conjunction with the water heater  10 . The mounting bracket  32 , in combination with the threaded spud  30  (see  FIGS. 3-4 ) may position a temperature sensor assembly  41  in a relatively precise location relative to the water heater tank  12  such that water temperature may be accurately and reliably measured and/or calculated. 
     In some instances, the mounting bracket  32  may include a component retaining region  34 , and a sensor portion  36  forming an elongated stem extending from the component retaining region  34 . In the illustrative embodiment, bracket  32  may be configured to retain a gas valve module and/or a water heater controller module (not explicitly shown) within component retaining region  34 , as well as a temperature sensor assembly  41  (see also  FIG. 3 ) within elongated stem. Component retaining region  34  may form at least a portion of a housing of a gas control unit, such as gas control unit  18  of  FIG. 1 , but this is not required. In some instances, component retaining region  34  may include an opening  48  connecting the component retaining region  34  a hollow portion  50  of the sensor portion  36 . In some cases, opening  48  may extend from the component retaining region  34  and through the sensor portion  36  to an open end  37  of the sensor portion defining a hollow portion  50 . 
     Bracket  32  may be formed of any suitable material. In some cases, bracket  32  may include non-metallic materials such as a polymeric material, glass, ceramic, plastic, and the like. In some cases, bracket  32  may be manufactured as a single piece by injection molding a nylon material such Hylon®, available from Entec Polymers in Manchester, Tenn. It is contemplated that in some cases, bracket  32  may not be formed entirely from the same material, or bracket  32  may not be formed as a single piece. In some cases, bracket  32  may include metallic materials, if desired. 
     In the illustrative embodiment, sensor portion  36  of the bracket  32  may include an elongated stem extending from component retaining region  34 . Sensor portion  36  may include an internal hollow portion  50  (shown in more detail in  FIG. 3 ) for slidably receiving a temperature sensor assembly  41 . In the embodiment shown, the temperature sensor assembly  41  may extend out of an open end  37  of the sensor portion  36  and away from the component retaining region  34 . The elongated stem of sensor portion  36  may include a first portion  40  and a threaded region  38  extending around the exterior of the sensor portion  36 . In some instances, as illustrated, threaded region  38  can be used to secure bracket  32  to or within a threaded aperture  31  ( FIG. 3 ) of a water heater spud  30 . As discussed in more detail below, the sensor portion  36  and temperature sensor assembly  41  may be configured such that when the threaded region  38  is engaged with the threaded water heater spud  30 , a temperature sensor  52  (see  FIG. 3 ) may be positioned in a relatively precise position relative to the water heater tank  12 . 
     In some embodiments, bracket  32  may also include two (or more) bosses  44  on a first lateral side, and two (or more) bosses  44  on a second opposing lateral side. While bracket  32  is shown having four bosses  44 , it is contemplated that bracket  32  may have any number of bosses  44  as desired, for example, but not limited to, one, two, three, or more. Additionally, it is contemplated that bosses  44  may be disposed on fewer than, or more than, two lateral sides. Bosses  44  may provide, among other things, an area for torque to be applied directly to the bracket  32  during installation. For example, an installation tool may grip and apply torque to bosses  44  to threadably engage threaded region  38  of sensor portion  36  with the threaded water heater spud  30  on a water heater tank  12 . In some instances, bosses  44  may further include a rib  46  disposed between adjacent bosses  44 . Rib(s)  46  may provide additional support to the bracket  32 , and may also help prevent an installation tool from contacting the component retaining region  34  of bracket  32  during installation. 
     Turning to  FIG. 3 , which is cross-section of an illustrative, but non-limiting mounting bracket  32  and temperature sensor assembly  41  engaging a threaded aperture  31  of a water heater spud  30 . As discussed above, the water heater tank  12  may include a feature(s) for mounting a non-immersion type temperature sensor  52 . For example, the water heater tank  12  may include a spud  30  extending from the outer wall  13  thereof. In some instances, the spud  30  may include a threaded aperture  31  for mating with the threaded region  38  of the mounting bracket  32 . However it is contemplated that the other retaining feature(s), such an adhesive, friction fit, snap fit, clips, etc. may be used to secure the sensor portion  36  of the bracket  32  to the water heater tank  12 . 
     The temperature sensor assembly  41  may include a thermal conduction temperature sensor  52 , sometimes disposed within a capsule  42 . It is contemplated that the temperature sensor  52  may be of any type desired and is not necessarily limited to a thermal conduction temperature sensor. The temperature sensor  52  may be electrically connected to a control unit (such as gas control unit  18  in  FIG. 1 ) via an electrical cable  60  and connection element  58  (e.g. plug). In the illustrative embodiment shown, capsule  42  may have a generally cylindrical shape, although this is not required. It is contemplated that the capsule may have any cross-sectional shape desired such as, but not limited to: rectangular, square, elliptical, polygonal, etc. It is further contemplated that the capsule  42  may be sized and shaped to conform to the shape of the temperature sensor  52 . However, it is contemplated that the capsule  42  may take any shape as desired. It is contemplated that while the capsule  42  is illustrated has having a first end  43  with a smaller cross-sectional area, the first end  43  may be similar in size or larger than the second end  45  of the capsule  42 . 
     In some embodiments, capsule  42  may include feature(s) adjacent the second end  45  that are configured to maintain a portion of the temperature sensor assembly  41  within the hollow portion  50  of the sensor portion  36 . For example, in some instances, the second end  45  of the capsule  42  may include one or more protrusions extending away from the capsule  42 . The one or more protrusions may be configured to engage a mating feature, such as a protrusion adjacent the open end  37  on the sensor portion  36 , to maintain the temperature sensor assembly  41  within the hollow portion  50  (e.g. to help ensure that the temperature sensor assembly  41  does not slide out of the open end  37  on the sensor portion  36 ). It is contemplated that the one or more protrusions may be temporarily deformed to allow the temperature sensor assembly  41  to be initially assembled within the hollow portion  50  of sensor portion  36  by inserting the temperature assembly through the open end  37  and into the hollow portion  50 . It is further contemplated that the protrusions may also be temporarily deformed if the temperature sensor  52  and/or temperature sensor assembly  41  need to be removed. 
     In some instances, the temperature sensor assembly  41  may be slidably disposed within or about the hollow portion  50 . In some cases, the sensor portion  36  may include a lip or shelf  55  generally perpendicular to the elongated stem to maintain the temperature sensor assembly  41  within a region of the sensor portion  36  between the shelf  55  and the open end  37 . The temperature sensor assembly  41  may be movable within the hollow portion  50  to accommodate various size spuds  30 , manufacturing tolerances, equipment variations, and/or other variations as desired. For example, if a shorter spud is used, the second end  45  of the capsule  42  may be positioned closer to the shelf  55 , whereas if a longer spud  30  is used, the second end  45  may be positioned further from the shelf  55 . The sensor portion  36  may include a compliant body  54 , such as a biasing element or spring, configured to maintain the temperature sensor assembly  41  in a proper position. In some cases, it is contemplated that the biasing element  54  may be sized to accommodate various water tank spud  30  lengths. 
     The biasing element  54  may have a first end  53  configured to engage temperature sensor assembly  41 , and a second end  56  configured to contact shelf  55 . In some instances, the biasing element  54  may be partially disposed within capsule  42 . The biasing element  54  may be configured to bias the temperature sensor assembly  41  away from the shelf  55 . When the sensor portion  36  of the mounting bracket  32  is engaged with the water tank spud  30 , the biasing element  54  may exert sufficient force to bias the temperature sensor assembly  41  towards the water heater tank  12  such that a first end  43  of the temperature sensor assembly  41  physically contacts the outer wall  13  of the water heater tank  12 . Physical contact between the first end  43  of the temperature sensor assembly  41  and the outer wall of the water heater tank  12  may increase thermal conduction between the temperature sensor  52  and the water heater tank  12 , which may increase the accuracy and reliability of the temperature sensor measurement. 
     Turning now to  FIG. 4 , which is cross-section of another illustrative, but non-limiting mounting bracket  132  and temperature sensor assembly  141  engaging a threaded aperture  31  of a water heater spud  30 . It is contemplated that the mounting bracket  132  may be similar in form and function to mounting bracket  32  of  FIG. 3 . For example, while not explicitly shown, the mounting bracket  132  may include bosses and/or ribs to facilitate installation of the bracket  132  and/or to provide additional support. The mounting bracket  132  in combination with the threaded spud  30  may position a temperature sensor assembly  141  in a proper or desired location relative to the water heater tank  12  such that water temperature may be accurately and reliably measured and/or calculated. 
     In some instances, the mounting bracket  132  may include a component retaining region  134 , and a sensor portion  136  extending from the component retaining region  134  forming an elongated stem. In the illustrative embodiment, bracket  132  may be configured to retain a gas valve module and/or a water heater controller module (not explicitly shown) within component retaining region  134 , as well as a temperature sensor assembly  141  within elongated stem of sensor portion  136 . Component retaining region  134  may form at least a portion of a housing of a gas control unit, such as gas control unit  118  of  FIG. 1 , but this is not required. In some instances, component retaining region  134  may include an opening  148  connecting the component retaining region  134  a hollow portion  150  of the sensor portion  136 . Opening  148  may extend from the component retaining region  134  and through the sensor portion  136  to an open end  137  of the sensor portion defining a hollow portion  150 . 
     Bracket  132  may be formed of any suitable material. In some cases, bracket  132  may include non-metallic materials such as a polymeric material, glass, ceramic, plastic, and the like. In some cases, bracket  132  may be manufactured as a single piece by injection molding a nylon material such Hylon®, available from Entec Polymers in Manchester, Tenn. It is contemplated that in some cases, bracket  132  may not be formed entirely from the same material, or bracket  132  may not be formed as a single piece. In some cases, bracket  132  may include metallic materials, if desired. 
     In the illustrative embodiment, sensor portion  136  of the bracket  132  may include an elongated stem extending from component retaining region  134 . Sensor portion  136  may include an internal hollow portion  150  for slidably receiving a temperature sensor assembly  141 . In the embodiment shown, the temperature sensor assembly  141  may extend out of an open end  137  of the sensor portion  136  and away from the component retaining region  134 . The elongated stem of sensor portion  136  may include a first portion  140  and a threaded region  138  extending around the exterior of the sensor portion  136 . In some instances, as illustrated, threaded region  138  can be used to secure bracket  132  to or within a threaded aperture  131  of a water heater spud  130 . As discussed in more detail below, the sensor portion  136  and temperature sensor assembly  141  may be configured such that when the threaded region  138  is engaged with the threaded water heater spud  130 , a temperature sensor  152  may be positioned in a relatively precise position relative to the water heater tank  12 . 
     It is contemplated that the temperature sensor assembly  141  may include an infrared (IR) temperature sensor  152  disposed within and attached to a capsule  142 . It is contemplated that the temperature sensor  152  may be of any type desired and is not necessarily limited to an IR temperature sensor. The temperature sensor  152  may be electrically connected to a control unit (such as gas control unit  18  in  FIG. 1 ) via an electrical cable  160  and connection element  158  (e.g. plug). Capsule  142  may include a first portion  145  having a first cross sectional area and a second portion  143  having a second cross-sectional area. In some instances, the second cross-sectional area may be larger than the first cross-sectional area, although this is not required. It is contemplated that in some instances, the first portion  145  may have a cross-section that is similar in size or smaller than the cross-section of the second portion  143 . It is contemplated that the capsule may have any cross-sectional shape desired such as, but not limited to: rectangular, square, elliptical, polygonal, etc. In some instances, the cross-sectional shapes of the first portion  145  and the second portion  143  may be different. For example, in some embodiments, the first portion  145  may have a generally circular cross-sectional shape while the second portion  143  may have a generally square cross-sectional shape. In other embodiments, the cross-sectional shapes of the first and second portions  145 ,  143  may be the same or similar. In some embodiments, the first and second portions  145 ,  143  may be formed from a single piece or a unitary structure. In other embodiments, the first and second portions  145 .  143  may be separate components. The first and second portions  145 ,  143  may be attached in any manner known in the art, such as, but not limited to, welding, brazing, soldering, adhesive, friction fit, snap fit, fasteners, etc. 
     In some embodiments, the second portion  143  may include a generally solid end  139  adjacent to the first portion  145  of the capsule  142 . Temperature sensor  152  may be mounted or otherwise affixed to the solid end  139  such that the temperature sensor  152  faces a water heater tank  12  when the mounting bracket  132  is engaged with a water tank spud  30 . Temperature sensor  152  may be mounted to the capsule  142  such that the temperature sensor  152  is partially enclosed within the capsule  142 , but this is not required. It is contemplated that the second portion  143  may be sized such that a when the mounting bracket  132  is engaged with a water tank spud  30 , the temperature sensor  152  is spaced a predetermined distance ‘d’ from the outer wall  13  of the water heater tank  12 , as shown in  FIG. 4 . For example, the temperature sensor  152  may be positioned approximately 0.10 inches, 0.25 inches, anywhere between 0.10 inches and 0.25 inches, or any other suitable distance from the outer wall  13  of the water heater tank  12 . Capsule  142  may be formed from a relatively non-compliant and/or relatively non-deformable material such that when a biasing force is exerted on the capsule  142  by biasing member  154 , the capsule  142  resists deformation and maintains the temperature sensor  152  at a fixed distance from the outer wall  13  of the water heater tank  12 . 
     In some instances, capsule  142  may include features adjacent the first portion  145  thereof that are configured to maintain a portion of the temperature sensor assembly  141  within the hollow portion  150  of the sensor portion  136 . For example, in some cases, the first portion  145  of the capsule  142  may include one or more protrusions extending away from the capsule  142 . The one or more protrusions may be configured to engage a mating feature such as a protrusion adjacent the open end  137 , on the sensor portion  136  to maintain the temperature sensor assembly  141  within the hollow portion  150 . It is contemplated that the one or more protrusions may be temporarily deformed to allow the temperature sensor assembly  141  to be assembled within the hollow portion  150  of sensor portion  136  by inserting the temperature assembly through the open end  137  and into the hollow portion  150 . It is further contemplated that the protrusions may also be temporarily deformed if the temperature sensor  152  and/or temperature sensor assembly  141  needs to be removed. 
     In some instances, the temperature sensor assembly  141  may be slidably disposed within or about the hollow portion  150 . The sensor portion  136  may include a lip or shelf  155  generally perpendicular to the elongated stem to maintain the temperature sensor assembly  141  within a region of the sensor portion  136  between the shelf  155  and the open end  137 . The temperature sensor assembly  141  may be movable within the hollow portion  150  to accommodate various size spuds  30 . For example, if a shorter spud is used, the first portion  145  of the capsule  142  may be positioned closer to the shelf  155 , whereas if a longer spud  30  is used, the first portion  145  may be positioned further from the shelf  155 . The sensor portion  136  may further include a compliant body  154 , such as a biasing element or spring, configured to maintain the temperature sensor assembly  141  in a specified position. It is contemplated that the biasing element  154  may be sized to accommodate various water tank spud  30  lengths. For example, the biasing element  154  may have a first end  153  configured to contact the generally solid end  139  of the capsule  142  and a second end  156  configured to contact shelf  155 . In some instances, the biasing element  154  may be partially disposed within capsule  142 . The biasing element  154  may be configured to bias the temperature sensor assembly  141  away from the shelf  155 . When the sensor portion  136  of the mounting bracket  132  is engaged with the water tank spud  30 , the biasing element  154  may be configured to bias the temperature sensor assembly  141  towards the water heater tank  12  such that a second portion  143  of the capsule  142  physically contacts the outer wall  13  of the water heater tank  12 . The biasing element  154  may exert sufficient force on the temperature sensor assembly  141  to continually bias the temperature sensor assembly  141  towards the outer wall  13  of the water heater tank  12 . Physical contact between the second portion  143  of the capsule  142  and the outer wall  13  of the water heater tank  12  may maintain the temperature sensor  152  a fixed distance ‘d’ from the outer wall  13  of the water heater tank  12  such that water temperature may be accurately and reliably measured and/or calculated. 
     The disclosure should not be considered limited to the particular examples described above, but rather should be understood to cover all aspects of the disclosure as set out in the attached claims. Various modifications, equivalent processes, as well as numerous structures to which the disclosure can be applicable will be readily apparent to those of skill in the art upon review of the instant specification.

Technology Category: g