Patent Publication Number: US-2015082879-A1

Title: Fluid flow sensor with reverse-installation detection

Description:
FIELD 
     The present disclosure relates to an improved fluid flow sensor and a method associated with quickly determining whether the sensor has been installed in an improper orientation relative to the direction of fluid flowing through a system. 
     BACKGROUND 
     This section provides background information related to the present disclosure and is not necessarily prior art. 
     The use of fluid flow sensors in household and industrial fluid delivery and/or fluid monitoring systems is common. For example, a fluid flow sensor may be installed in a household dishwasher to monitor and help control the volume of water flowing into the dishwasher to circumvent a potential under-fill or over-fill condition from occurring. 
     In a typical fluid system, generally, fluid flows through a supply hose in a single direction (i.e., either in a left to right direction, or in a right to left direction). A fluid flow sensor can generally connect to the supply hose in either orientation relative to the direction of fluid flowing through the hose. Accordingly, depending on the orientation that the sensor is connected to the hose dictates whether fluid will flow through the sensor in a left to right direction, or in a right to left direction. However, for the fluid flow sensor to function properly, the sensor must be installed correctly; that is, the sensor must be connected to the hose in proper orientation relative to the direction of fluid flowing through the hose. A sensor that has been installed in an improper orientation relative to the direction of fluid flow can, for example, fail to accurately monitor and control the volume of fluid passing through the system. 
     Improper orientation, or reverse-installation, can occur at the assembly facility where the sensor is first connected to the fluid system and/or in the field during sensor service or replacement. Unfortunately, there currently lacks a fluid flow sensor and a method associated with quickly determining whether the sensor has been installed in an improper orientation relative to the direction of fluid flowing through a system. 
     Fluid flow sensors and methods associated with detecting the presence of fluid in a fluid system and determining the rate of fluid flow through a system are generally known. For example, a sensor for realizing whether a threshold fluid level has been attained in a system is shown and described in U.S. Pat. No. 6,862,932, entitled “Liquid Level Sensor,” issued Mar. 8, 2005 and owned by Therm-O-Disc, Incorporated, the assignee of the present patent application, the disclosure of which is hereby incorporated by reference. A sensor for realizing the rate of fluid flow through a system is shown and described in U.S. Pat. No. 7,333,899, entitled “Fluid Flow Rate Sensor and Method of Operation,” issued Feb. 19, 2008 and in U.S. Pat. No. 7,685,875, entitled “Fluid Flow Rate Sensor and Method of Operation,” issued Mar. 30, 2010, both owned by Therm-O-Disc, Incorporated, the assignee of the present patent application, the disclosures of which are hereby incorporated by reference. 
     SUMMARY 
     This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features. 
     A fluid flow sensor and a method associated with quickly determining whether the sensor has been installed in an improper orientation relative to the direction of fluid flowing through a system is disclosed. 
     In one form, the disclosure provides a fluid flow sensor comprising a probe with a detection module adapted to change condition in response to a direction of flow of fluid through a system. The detection module comprises a a first heating circuit having at least one resistor heater, a second heating circuit having at least one resistor heater, a fluid flow rate detection circuit, and a reverse-installation detection circuit having at least one negative temperature coefficient thermistor. The negative temperature coefficient thermistor of the reverse-installation detection circuit is adapted to provide a voltage that varies in response to a change in temperature. 
     The fluid flow sensor further comprises a control module electrically connected to the probe that monitors the condition of the detection module and generates an output that is indicative of the direction of flow of fluid. The fluid flow sensor also comprises an I/O module connected to the control module to communicate the output of the control module to another device or a user. 
     In another form, the present disclosure provides a fluid flow sensor comprising a detection module having a first heating circuit, a second heating circuit, a fluid flow rate detection circuit and a means for determining a direction of flow of fluid through a system. 
     In yet another form, the present disclosure provides a fluid flow sensor for detecting the direction of flow of fluid through a system comprising the steps of measuring a temperature of a fifth negative temperature coefficient thermistor, applying a voltage to a second resistor heater to generate heat that can be transferred to the fifth negative temperature coefficient thermistor, measuring a temperature of the fifth negative temperature coefficient thermistor, calculating a change in temperature of the fifth negative temperature coefficient thermistor, determining a direction of flow of fluid through the system from the change in temperature of the fifth negative temperature coefficient thermistor, and generating an output that is indicative of the direction of flow of fluid through the system. 
     Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. 
    
    
     
       DRAWINGS 
       The present disclosure will become more fully understood from the detailed description and the accompanying drawings, wherein: 
         FIG. 1  is a schematic block diagram of a fluid flow sensor according to the disclosure; 
         FIG. 2  is a front view of an exemplary probe, shown in partial cross-section, for use with the fluid flow sensor according to the disclosure; 
         FIG. 3  is an end view of the probe of  FIG. 2 ; 
         FIG. 4  is a circuit schematic for a representative detection module for use with the probe of  FIG. 2 ; 
         FIGS. 5A and 5B  are representative schematic block diagrams of the detection module of  FIG. 4  for use with the probe of  FIG. 2 ; 
         FIG. 6  is a flow chart describing the operation of the fluid flow sensor according to the disclosure; 
         FIG. 7A  shows a computational fluid dynamic (CFD) model of fluid flowing about the detection module the probe of  FIG. 2  when the probe is installed in desired, forward orientation relative to the direction of fluid flow; and 
         FIG. 7B  shows a computational fluid dynamic (CFD) model of fluid flowing about the detection module of the probe of  FIG. 2  when the probe is installed in undesired, reverse orientation relative to the direction of fluid flow. 
     
    
    
     Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings. 
     DETAILED DESCRIPTION 
     Example embodiments are provided so that this disclosure will be thorough, and will fully convey the scope to those who are skilled in the art. Numerous specific details are set forth such as examples of specific components, devices, and methods, to provide a thorough understanding of embodiments of the present disclosure. It will be apparent to those skilled in the art that specific details need not be employed, that example embodiments may be embodied in many different forms and that neither should be construed to limit the scope of the disclosure. The example embodiments will now be described more fully with reference to the accompanying drawings. 
     The present disclosure provides a fluid flow sensor and method associated with quickly determining whether the sensor has been installed in an improper orientation relative to the direction of fluid flowing through a system. By way of example only, it is presently contemplated that the fluid flow sensor of the disclosure can be incorporated into a household dishwasher to monitor water flow therethrough. 
       FIG. 1  generally shows the major components of the fluid flow sensor  10 . The sensor  10  generally includes a probe module  12 , a control module  14  in communication with the probe module  12 , and an input/output (I/O) module  16  in communication with the control module  14 . As used throughout this description, the term “module” refers to an application specific integrated circuit (ASIC), an electronic circuit, a processor (shared, dedicated, or group) and memory that executes one or more software or firmware programs, a combinational logic circuit, and/or other suitable components that provide the described functionality. 
     The sensor  10  is of the thermo-anemometer-type and contains no moving parts. The probe  12  is typically disposed in a fluid environment  20 . The sensor can be used to determine the flow rate of a fluid  18  and the direction of fluid flow  18 . As described further herein, the sensor  10  can quickly determine whether the probe  12  is installed in an improper or reverse orientation relative to the direction of fluid flow  18 . 
     When the probe  12  is subjected to fluid flow  18 , the probe  12  experiences a change in condition represented by a signal  22  (e.g., a voltage). The control module  14  continuously monitors the signal  22 . According to one aspect of the disclosure, the control module processes the signal  22  and generates an output  24  that is indicative of the installation orientation of the probe  12  relative to the direction of the flow of fluid  18  through the probe. In another aspect of the disclosure, the control module processes the signal  22  and generates an output  24  that is indicative of the flow rate for the fluid  18 . The I/O module  16  provides a means by which the sensor  10  can communicate the output  24  to other devices(s) or a user. 
     An embodiment of a probe  100  for use in the sensor  10  is shown in  FIGS. 2 and 3 . The probe  100  generally comprises a body  102  and a detection module  104 . The body  102 , as shown, is a generally cylindrically shaped tubular member having a passageway  106  extending throughout its entire length along a longitudinal axis  107 . Annular flanges  108 ,  110  may be located at opposite ends of the body  102  to facilitate connection of the probe  100  to a fluid delivery source, such as, for example, a flexible water supply hose (not shown) of a household dishwasher (not shown). 
     The probe  100  can generally connect to the supply hose in either orientation relative to the direction of fluid flowing through the hose. Accordingly, depending on the orientation that the probe  100  is connected to the hose dictates whether fluid will flow  18  through the passageway  106  in a left to right direction, or in a right to left direction. As discussed above, because the sensor  10  may not function properly when fluid flows  18  through the passageway  106  in one direction versus the other, it is desirable for the sensor  10  to quickly determine if the probe  100  has been installed in an improper or reverse orientation relative to the direction of fluid flow  18 . 
     Located intermediate the annular flanges  108 ,  110  is a housing  116 . The housing  116  extends through the body  102  in a direction generally perpendicular to the longitudinal axis  107 , and is disposed within the passageway  106 . The shape of the housing  116  is designed to promote laminar fluid flow  18  through the passageway  106  and across the surface of the housing  116 . The detection module  104  is received within the housing  116  such that the housing  116  encapsulates a portion of the detection module  104  and protects it from physical contact with the fluid  18 . The housing  116  is, however, capable of conducting thermal energy between the fluid  18  and the detection module  104 . 
     Both the body  102  and the housing  116  are preferably manufactured from a thermally conductive polymer, such as, for example, polypropylene, polyvinyl chloride (PVC), polyacetylene, polyparaphenylene, polypyrrole, and polyaniline. Ceramic and/or glass fillers mixed in with these base polymers have been shown to greatly enhance the material&#39;s thermal conductivity. One such material is known under the trade designation Konduit MT-210-14 and is available from GE/LNP. 
     A representative detection module  104  can be understood with reference to  FIGS. 2 ,  4 ,  5 A and  5 B. The detection module  104  is preferably highly thermally conductive and has a low thermal mass. The detection module  104  comprises a first heating circuit  112 , a second heating circuit  113 , a reverse-installation detection circuit  114 , and a fluid flow rate detection circuit  115 . The first heating circuit  112 , second heating circuit  113 , reverse-installation detection circuit  114 , and fluid flow rate detection circuit  115  can be deposited on a thermally conductive, glass-epoxy printed circuit board (PCB) substrate  120 . 
     Referring to  FIG. 4 , the first heating circuit  112  comprises a resistor heater R 1 . Resistor heater R 1  is adapted to function as a primary heater and is operable to provide approximately 1.5 watts of power. The second heating circuit  113  comprises a resistor heater R 2 . Resistor heater R 2  is adapted to function as a secondary heater and is operable to provide approximately 500 milliwatts of power. Resistor heaters R 1 , R 2  can be arranged in parallel. 
     The reverse-installation detection circuit  114  comprises a negative temperature coefficient (NTC) thermistor NTC 5 , which is arranged to operate as a temperature sensing thermistor. 
     The fluid flow rate detection circuit  115  comprises a plurality of negative temperature coefficient (NTC) thermistors NTC 1 , NTC 2 , NTC 3 , NTC 4  that together form a 4-wire bridge circuit  132 . Thermistor NTC 1  is coupled in series with thermistor NTC 3  to form one leg of the bridge  132  and thermistor NTC 2  is coupled in series with thermistor NTC 4  to form the other leg of the bridge  132 . Together, thermistors NTC 1 , NTC 3  are coupled in parallel with thermistors NTC 2 , NTC 4 . 
     The circuit schematic  122  of  FIG. 4  also shows a plurality of traces  124 ,  125 ,  126 ,  127 ,  128 ,  129 ,  130 ,  131  that lead to a plurality of pin connectors P 1 , P 2 , P 3 , P 4 , P 5 , P 6 , P 7 , P 8 , respectively. The first heating circuit  112  includes traces  128 ,  130  and pins P 5 , P 7 . Trace  128  terminates at pin P 5 , which is connected to ground. Trace  130  terminates at pin P 7 , where a voltage V HR1  is applied to turn ON and energize the resistor heater R 1 . 
     The second heating circuit  113  includes traces  127 ,  128  and pins P 4 , P 5 . Trace  127  terminates at pin P 4 , where a voltage V HR2  is applied to turn ON and energize resistor heater R 2 . As described above, trace  128  terminates at pin P 5 , which is connected to ground. 
     The reverse-installation detection circuit  114  includes traces  124 ,  125  and pins P 1 , P 2 . An output voltage V OUT2 , which is calibrated to represent a temperature of thermistor NTC 5  can be read at pins P 1 , P 2 . 
     The fluid flow rate detection circuit  115  includes traces  124 ,  126 ,  129 ,  131  and pins P 1 , P 3 , P 6 , P 8 . Trace  124  terminates at pin P 1 , which is connected to ground. Trace  129  terminates at pin P 6 , where a reference voltage V REF1  is applied. Traces  126 ,  131  are coupled to opposite legs of the bridge  132  and terminate at pins P 3 , P 8 , respectively. An output voltage V OUT1 , which is calibrated to represent a temperature difference across the bridge  132  and between thermistors NTC 1 , NTC 3  and NTC 2 , NTC 4 , can be read at pins P 3 , P 8 . 
     Thermistors NTC 1 , NTC 2 , NTC 3 , NTC 4  are generally disposed on side A of the substrate  120 . Thermistors NTC 1 , NTC 2  are located generally proximate a first, downstream edge  136  of the substrate  120 . Thermistors NTC 3 , NTC 4  are located generally proximate a second, upstream edge  138  of the substrate  120 , opposite the first edge  136 . Thermistors NTC 1 , NTC 3  are generally located above thermistors NTC 2 , NTC 4 . 
     Thermistor NTC 5  and resistor heaters R 1 , R 2  are generally disposed on side B of the substrate  120 . It is understood, however, that resistor heater R 2  can be relocated to side A of the substrate  120 . As shown in  FIGS. 2 ,  5 A and  5 B, thermistor NTC 5  is located on the substrate  120  generally proximate second edge  138 . Resistor heater R 1  is located on the substrate  120  generally proximate the first edge  136  and opposite to thermistors NTC 1 , NTC 2  that are disposed on side A of the substrate  120 . 
     Resistor heater R 2  is generally located between thermistor NTC 5  and resistor heater R 1 , and can be positioned closer to the second edge  138  of the substrate  120 , and relatively proximate to thermistor NTC 5 . 
     As discussed below, heat energy from resistor heater R 1  is generally conducted to thermistors NTC 1 , NTC 2 . Heat energy from resistor heater R 1  is generally not, however, conducted to thermistors NTC 3 , NTC 4 , NTC 5 . 
     Thermistors NTC 3 , NTC 4 , disposed on side A of the substrate  120 , are positioned generally opposite thermistor NTC 5  and near resistor heater R 2 , both of which are disposed on side B of the substrate  120 . As will be described further below, heat energy from resistor heater R 2  can be conducted to thermistor NTC 5  depending on the direction of fluid flow  18  through the passageway  106  of the probe  100 . Heat energy from resistor heater R 2  is not, however, conducted to thermistors NTC 1 , NTC 2 , NTC 3 , NTC 4 . 
     The detection module  104  disposed on the PCB substrate  120  is generally received within the housing  116  such that it is generally perpendicular to the direction of fluid flow  18  through the passageway  106 . With particular reference to  FIG. 2 , resistor heaters R 1 , R 2  and thermistors NTC 1 , NTC 2 , NTC 3 , NTC 4 , NTC 5  are located within the housing  116  and lie within the passageway  106  of the body  102 . All of the pin connectors P 1 , P 2 , P 3 , P 4 , P 5 , P 6 , P 7 , P 8 , however, extend outward from the housing  116 . 
     The sensor  10  of the present disclosure can generally operate in two modes: a fluid flow rate detection mode and a reverse installation detection mode. Of course, it will be appreciated by persons skilled in the art that the reverse installation detection mode can also serve to determine the direction of fluid flow.  FIG. 6  is a flow chart describing an exemplary method employed by the sensor  10  to enable the sensor  10  to quickly determine whether the probe  100  has been installed in an improper or reverse orientation relative to the flow direction F of the fluid  18 . 
     First, the rate of fluid flow  18  through the probe  100  is determined. Preferably, a minimum threshold fluid flow rate through the probe  100  in the range of 1 to 5 liters per minute (LPM), should be present before the sensor  10  operates to detect the whether the probe  100  has been installed in a reverse orientation. If the rate of the fluid flow  18  through the probe  100  is below the minimum threshold fluid flow rate, the sensor&#39;s  10  ability to accurately determine whether the probe  100  has been properly installed relative to the direction F of flow of the fluid  18  can be compromised. 
     To determine the rate of fluid flow  18  through the environment  20 , at  150 , the control module  14  applies a voltage V HR1  to pin  7  to turn ON and energize resistor heater R 1 . As a result, the temperature (T i ) of thermistors NTC 1 , NTC 2  increases. The temperature of thermistors NTC 1 , NTC 2  is determined from the output voltage V OUT1 , which is read at pins P 3 , P 8  by the control module  14 , as described and taught in U.S. Pat. No. 7,333,899, entitled “Fluid Flow Rate Sensor and Method of Operation,” issued Feb. 19, 2008, which is hereby incorporated by reference. The temperature of thermistors NTC 3 , NTC 4 , NTC 5  is not, however, affected by turning ON and energizing resistor heater R 1  at  150 . The reference voltage V REF1  is applied to the fluid flow rate detection circuit  115 . 
     As fluid flows  18  through the passageway  106 , passes over and around the housing  116  and consequently flows over the portion of the detection module  104  enclosed within the housing  116 , heat energy is transferred from thermistors NTC 1 , NTC 2  to the fluid  18 . Accordingly, the temperature (T i ) of thermistors NTC 1 , NTC 2  changes over time (t). The temperature (T i ) of thermistors NTC 1 , NTC 2  and the output voltage V OUT1  is sampled by the control module  14  at discrete time intervals (e.g., 100 msec). 
     The use of four thermistors NTC 1 , NTC 2 , NTC 3 , NTC 4  in the fluid flow rate detection circuit  115  and their physical arrangement in the passageway  106  of the body  102  provides significant advantages. One significant advantage is that the output voltage V OUT1  automatically compensates for any ambient temperature changes, i.e., changes in the temperature of the fluid  18 . This is important because if significant and/or rapid changes in the fluid  18  temperature occurs, the output  24  of the sensor  10  could be distorted, thereby causing the sensor  10  to generate inaccurate results, as described and taught in U.S. Pat. No. 7,333,899, entitled “Fluid Flow Rate Sensor and Method of Operation,” issued Feb. 19, 2008. 
     Once the control module  14  samples the output voltage V OUT1  at discrete time intervals (e.g., 100 msec), the control module  14  then determines the rate of change of the temperature (T i ) over time (t) (i.e., it calculates dT i /dt). This process is repeated for a predetermined number of iterations (e.g., 10). Then, the smallest value of dT i /dt can be correlated to a fluid flow rate. At  152 , the control module compares the rate of fluid flow  18  to the minimum threshold fluid flow rate to determine whether to proceed to the next step. 
     As discussed above, if the rate of fluid flow  18  through the passageway  106  is below the minimum threshold fluid flow rate, the sensor&#39;s  10  ability to accurately detect the orientation of the probe  100  relative to the direction of fluid flow  18  can be diminished. Consequently, preferably, the process will not proceed until the rate of fluid flow  18  through the passageway  106  is at or above the minimum threshold fluid flow rate. 
     If the rate of fluid flowing  18  through the passageway  106  is above the minimum threshold fluid flow rate, at  154 , resistor heater R 1  is turned OFF and the process proceeds. At  156 , the control module  14  reads V OUT2  at P 1 , P 2  and records a temperature T 0  of thermistor NTC 5 . At  158 , the control module  14  then applies a voltage V HR2  to pin P 4 , to turn ON and energize resistor heater R 2 . As fluid  18  flows through the passageway  106  and passes over and around the housing  116  and consequently over the portion of the detection module  104  that is enclosed within the housing  116 , heat energy is transferred from resistor heater R 2  to the fluid  18 . The fluid  18 , therefore, heats as it passes the resistor heater R 2  and its temperature rises accordingly. 
       FIGS. 7A and 7B  illustrate computational fluid dynamic (CFD) models showing the temperature gradients of the heated fluid  18  flowing past the detection module  104  of the probe  100  when the resistor heater R 2  is ON and energized. Specifically,  FIG. 7A  shows the temperature gradients of the fluid flowing past the detection module  104  when the probe  100  is installed in a desired, forward orientation relative to the direction F of fluid flow and  FIG. 7B  shows the temperature gradients of the fluid flowing past the detection module  104  when the probe  100  is installed in a undesired, reverse orientation relative to the direction F of fluid flow. As shown in the models of  FIGS. 7A and 7B , the heated fluid can be represented with a plurality of temperature gradients  19 ,  21 ,  23  and  25 , where the highest temperature, represented at gradient  19 , is closest to the resistor heater R 2 , and decreasingly relatively lower temperatures are represented at gradients  21 ,  23 , and  25 , respectively, as the fluid  18  moves further away from the resistor heater R 2 . 
     Referring to  FIG. 7A , the probe  100  is installed in a desired, forward orientation relative to the direction F of fluid flow. In this installation configuration, thermistor NTC 5  is located upstream of the resistor heater R 2 . Consequently, when resistor heater R 2  is turned ON and energized at  158 , and heat is conducted from resistor heater R 2  to the fluid  18 , the heated fluid  19 ,  21 ,  23  and  25  flows away from thermistor NTC 5 . As such, heat energy from the heated fluid  19 ,  21 ,  23 ,  25  is not conducted to thermistor NTC 5  and the temperature T 1  of thermistor NTC 5  does not increase due to resistor heater R 2  being turned ON. 
     Conversely, with reference to  FIG. 7B , when the probe  100  is installed in an undesired, reverse orientation relative to the direction F of fluid flow, thermistor NTC 5  is located downstream of the resistor heater R 2 . In this reverse-orientation installation, the heated fluid  19 ,  21 ,  23 ,  25  generated by resistor heater R 2  flows toward and across thermistor NTC 5 . The heat energy from the heated fluid  19 ,  21 ,  23 ,  25 , therefore, is conducted to thermistor NTC 5 , thereby causing the temperature T 1  of thermistor NTC 5  to increase. An increase in temperature of thermistor NTC 5  can, therefore, be correlated to the installation orientation of the probe  100  relative to the direction F of fluid flow. 
     Referring back to  FIG. 6 , at  160 , the control module  14  monitors V OUT2  at P 1 , P 2  and records the temperature T 1  of thermistor NTC 5 . At  162 , the control module  14  calculates a temperature difference ΔT of thermistor NTC 5 , from temperature measurements taken at  160  and  156  (ΔT=T 1 −T 0 ). A temperature difference ΔT is then compared to a predetermined threshold value. The threshold value can range from about 0.1° C. to about 0.5° C. If the temperature difference ΔT is greater than the threshold value that indicates that the probe  100  has been installed in an improper, reverse orientation relative to the direction F of fluid flow  18 . 
     If a reverse installation condition is determined, resister R 2  is turned OFF at  168 , and the control module  14  generates an alarm at  170 , which can be communicated by the I/O module  16  to other device(s) and/or a user (e.g., audibly and/or visually) to convey the reverse installation condition of the probe  100 . The improper installation of the probe  100  can, therefore, be corrected. 
     If, however, the temperature difference ΔT at  164  is less than the predetermined threshold value, that indicates that the probe  100  is installed in a proper orientation relative to the direction F of fluid flow. Thereafter, the resistor heater R 2  is turned OFF at  166 . Once the sensor  10  confirms the proper installation orientation of the probe  100 , the sensor  10  can then be used to determine a fluid flow rate. 
     As mentioned above, it can be appreciated that the reverse-installation detection operating mode of the sensor  10  can also be used to determine whether there has been a change in the direction of flow of fluid through the probe  100 . In this regard, as described above, the sensor  10  of the disclosure can determine whether the probe  100  has been properly installed relative to a known or expected direction of fluid flow. If, however, after proper installation of the probe  100  accordingly, the sensor  10  can employ the foregoing method to determine whether the direction of fluid flow has changed (e.g., reversed). 
     It can be further understood that the sensor  10  described in the present disclosure may also be incorporated into a multi-function sensor such as the sensor shown and described in U.S. Pat. No. 7,775,105, entitled “Multi-Function Sensor,” issued Aug. 17, 2010 and owned by Therm-O-Disc, Incorporated, the assignee of the present patent application, the disclosure of which is hereby incorporated by reference. 
     The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.