SYSTEMS AND METHODS FOR CATHODIC PROTECTION

Description

FIELD OF THE DISCLOSURE

The present disclosure generally relates to systems and methods for cathodic protection and, more particularly, to impressed current cathodic protection for a tank of a water heater.

BACKGROUND OF THE DISCLOSURE

Conventional cathodic protection systems can be inefficient. Typically, current is applied in an uncontrolled or inefficient way that overprotects or under-protects a structure. In the context of water heaters, this can lead to increased cost and/or corrosion of the tank wall.

SUMMARY OF THE DISCLOSURE

According to one aspect of the present disclosure, a water heater includes a tank defining an interior for holding water, an anode extending into the interior, and cathodic protection circuitry electrically coupled with the anode. The cathodic protection circuitry is configured to repeatedly apply current and limit application of current to the anode. Application of current to the anode occurs during a first time and limiting application of current to the anode occurs during a second time. The control circuitry is configured to measure an electrical parameter representative of a charge of the tank during the second time and adjust a level of the current applied to the anode based on a value of the electrical parameter.

According to another aspect of the present disclosure, a method for cathodically protecting a tank of a water heater using an anode includes electrically coupling the anode to cathodic protection circuitry, repeatedly applying current, and limiting application of current to the anode. The application of current to the anode occurs during a first time, and limiting application of current to the anode occurs during a second time. The method includes measuring an electrical parameter representative of a charge of the tank during the second time and adjusting a level of the current applied to the anode based on a value of the electrical parameter.

According to yet another aspect of the present disclosure, a cathodic protection circuit for a water heater includes a constant current circuit electrically coupled with an anode of the water heater, a detection circuit, and an enable circuit. Control circuitry is configured to selectively and repeatedly enable, during a first time, and disable, during a second time, the constant current circuit by controlling the enable circuit, measure, via the detection circuit, a voltage representative of a charge of a tank of the water heater during the second time and adjust a level of the current applied to the anode based on a value of the electrical parameter.

These and other features, advantages, and objects of the present disclosure will be further understood and appreciated by those skilled in the art by reference to the following specification, claims, and appended drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is a simplified cross-sectional view of a water heater operating with a cathodic protection circuit;

FIG. 2 is an electrical schematic of a cathodic protection circuit for a water heater;

FIG. 3 is a timing diagram including four plots that demonstrate electrical signals applied to and/or monitored by a cathodic protection circuit, the signals not necessarily to scale;

FIG. 4 is a flowchart of a method for cathodically protecting a tank of a water heater using an anode;

FIG. 5 is a plot of voltage and current demonstrating the relationship between drive current, drive voltage, and off-state voltage for a water heater employing a cathodic protection circuit according to one aspect of the present disclosure; and

FIG. 6 is a flowchart of the method of FIG. 4 including further steps of a diagnostic mode for a cathodic protection circuit.

The components in the figures are not necessarily to scale, emphasis instead being placed upon illustrating the principles described herein.

DETAILED DESCRIPTION

The present illustrated embodiments reside primarily in combinations of method steps and apparatus components related to cathodic protection. Accordingly, the apparatus components and method steps have been represented, where appropriate, by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments of the present disclosure so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein. Further, like numerals in the description and drawings represent like elements.

Referring to FIGS. 1-6, reference numeral 10 generally designates a water heater 10. The water heater 10 includes a tank 12 defining an interior 14 for holding water 16. An anode 18 extends into the interior 14. Cathodic protection circuitry 20 is electrically coupled with the anode 18. The cathodic protection circuitry 20 is configured to repeatedly apply current and limit application of current to the anode 18. The application of current to the anode 18 occurs during a first time T1 and limiting application of current to the anode 18 occurs during a second time T2. The cathodic protection circuitry 20 is configured to measure an electrical parameter representative of a charge of the tank 12 during the second time T2 and adjust a level of the current applied to the anode 18 based on a value of the electrical parameter.

The cathodic protection circuitry 20 can include a cathodic protection circuitry 20 that interacts with and/or includes the components of the water heater 10. For example, the cathodic protection circuitry 20 can include conductive fasteners 24, wires, or other intermediate conductive components considered part of a water 16 appliance and the cathodic protection circuitry 20.

Still referring to FIGS. 1-6, the water heater 10 and corresponding cathodic protection circuitry 20 can provide for enhanced efficiency (e.g., power efficiency) and protection by providing constant current and optimized detection techniques to gather information about the tank 12. By gathering this information regarding electrical conditions of the water 16 and the tank 12, the cathodic protection system can determine, or estimate, optimal operating conditions for corrosion protection. The corrosion protection can further be enhanced by minimizing or reducing off-times for the cathodic protection circuitry 20 by taking quick and accurate readings of parameters of the water heater 10 without substantially interfering with application of current.

Referring now to FIG. 1, the water heater 10 is provided demonstrating cathodic protection of a wall 22 of the tank 12. The wall 22 can comprise a steel portion coated by an enamel layer that can limit corrosion of the wall 22. The cathodic protection circuitry 20 can electrically connect with the steel portion via a metallic fastener 24 which can also connect to ground, as illustrated. For example, the steel can be electrically coupled to a ground terminal of the circuit breaker system of a facility or otherwise grounded.

Over time, the enamel layer can be worn, and areas of the steel layer can be exposed to the water 16, which can lead to corrosion without other electron sources. The tank 12 can be part of any water heating appliance, such as a traditional tank water heater 10, a tankless water heating appliance having a vessel for storing water 16. Further, the cathodic protection circuitry 20 can be provided adjacent to and/or above the tank 12, such as within a shroud atop the tank 12. While illustrated as being mounted to an upper portion 28 of the tank 12, the anode 18 can be an anode rod and be disposed and can extend into the interior 14 of the tank 12 from any location along the wall 22 (e.g., a base 30 of the tank 12 or side 32 of the tank 12). It is further contemplated that the tank 12 may be surrounded by a jacket and that other components of the water heater 10 not shown may be incorporated into a water heater 10 employing the present cathodic protection circuitry 20.

Still referring to FIG. 1, the cathodic protection circuitry 20 can be configured to apply an electrical current to the anode 18 via a positive terminal 34 of the cathodic protection circuitry 20. A negative terminal 36 of the cathodic protection circuitry 20 is shorted to ground 26, and the tank 12, which is also shorted to ground 26. The electrical current flows from the positive terminal 34 of the cathodic protection circuitry 20, through the anode 18, through an electrolyte (e.g., the water 16), to a cathode, which in the present case is the wall 22 of the tank 12, and to the negative terminal 36 of the cathodic protection circuitry 20. Accordingly, electrons flow from the negative terminal 36 of the cathodic protection circuitry 20, through the cathode (e.g., the tank 12), through the electrolyte, to the anode 18, and to the positive terminal 34 of the cathodic protection circuitry 20. In effect, the cathodic protection circuitry 20 pushes electrons onto the tank 12, making it negatively charged relative to the anode 18. The excess electrons on the tank 12 repel other electrons to prevent oxidation (e.g., loss of metal ions). The anode 18, which is connected to the positive terminal 34, assists in completing the cathodic protection circuitry 20 by drawing electrons from the water heater 10 and the water 16. In this way, the cathodic protection circuitry 20 limits corrosion of the wall 22 by providing an alternative source for electrons.

Referring now to FIG. 2, the cathodic protection circuit 20 can generally include a drive circuit 38, a detection circuit 40, an enable circuit 42, and control circuitry 44, which is configured to control the drive circuit 38 and the enable circuit 42, as well as monitor the detection circuit 40. In general, the control circuitry 44 can communicate signals to set a constant current level provided by the drive circuit 38 and selectively enable or disable the drive circuit 38 via the enable circuit 42 thereby controlling the enable circuit 42 and the drive circuit 38. The control circuitry 44 receives signals indicative of electrical parameters about the water heater 10 via the detection circuit 40.

The cathodic protection circuitry 20 can be powered via a DC power supply that can provide a supply voltage 46 relative to ground 26. The supply voltage 46 can be provided via a battery and/or be drawn from a standard alternating-current (AC) supply from a household voltage or other commercial voltage supply. In general, the control circuitry 44 can include a controller 48 having a processor 50 and memory 52. The memory 52 can store instructions that, when executed by the processor 50, cause the controller 48 to perform various functions related to control of the cathodic protection circuitry 20. For example, the memory 52 can store instructions related to repeatedly applying and limiting application of electrical current to the anode 18, measuring electrical parameters related to the tank 12, adjusting a level of current applied to the anode 18, executing a diagnostic algorithm to determine target voltage, or any other function related to cathodic protection described herein. The memory 52 may store various values that are read by the detection circuit 40 or that are monitored by the detection circuit 40, such as target voltages and target currents, relationships between voltage and currents applied to the tank 12, functional relationships between a drive voltage and an off state voltage of the tank 12, and the like.

With continued reference to FIG. 2, the controller 48 can be configured to communicate a pulse width modulated (PWM) signal on a control node 54 to a digital-to-analog (DAC 56) that feeds the drive circuitry 38. An output node 58 of the DAC 56 feeds into the drive circuit 38. The PWM signal can be representative of a target current to be applied to the anode 18 to charge the water heater 10. For example, the PWM signal can be controlled to a particular duty cycle, represented as a percentage between 0% and 100%, where the duty cycle corresponds to the current level output by the drive circuit 38. For example, a 50% duty cycle of the PWM signal can result in half of the maximum current to be applied to the water heater 10. The DAC 56 can be configured to convert the PWM signal into an analog signal of a constant voltage.

The constant voltage output from the DAC 56 is fed into a first stage 60 of a two-stage constant current supply of the drive circuit 38. Each of the first stage 60 and a second stage 62 (downstream of the first stage 60) can include an operational amplifier (op amp) upstream of a voltage divider connected to a switch. Accordingly, a first op amp 64, a second op amp 66, a first voltage divider 68, a second voltage divider 70, a first switch 72, and a second switch 74 are provided by the drive circuit 38. The first stage 60 and the second stage 62 are electrically connected via an intermediate node 76 that carries an intermediate voltage representative of, or proportional to, the drive voltage for the water heater 10. The intermediate voltage can be controlled by the output node 58 of the DAC 56, the voltage of which is ultimately based on the PWM signal from the control circuitry 44.

By way of example, in operation, the DAC 56 outputs a voltage on the output node 58 of 3V (e.g., selected between 0V and 5V), alternatively referred to as the input voltage of the drive circuit 38, based on the PWM signal provided by the control circuitry 44. The input voltage is fed into a non-inverting input of the first op amp 64. The first op amp 64 outputs the power required to bring its inverting input to match the input voltage (3V in this example). When the drive circuit 38 is enabled, which is discussed further below, a voltage drop is formed across a first resistor 78 (part of the first voltage divider 68) to ground 26, thereby resulting in a current determined by Ohm's law. In the present case, if the first resistor 78 has a value of 3 kilo-ohms (kohms), the current through the first resistor 78 (first stage current) is 1 mA. The first stage 60 current is drawn from the supply voltage 46 and through a second resistor 80 of the first voltage divider 68 that sets an intermediate voltage on the intermediate node 76 based on a voltage drop across the second resistor 80. For example, if the second resistor 80 has a value of 1 kohm, the voltage drops across the second resistor 80 (e.g., the intermediate voltage) [12V−1V]=11V.

Referring now to the second stage 62 of the drive circuit 38 of FIG. 2, the intermediate voltage is applied to the non-inverting input of the second op amp 66. Accordingly, the second op amp 66 outputs the power required to bring its inverting input to match the intermediate voltage. Continuing with the example above of an intermediate voltage of 11V, a voltage drops across a third resistor 82 (part of the second voltage divider 70) is formed and determines the current output by the drive circuit 38 to the anode 18. In the present example, for a value of 10 ohms of the third resistor 82, the output voltage, or drive voltage, is [12V−11V]=1V, and the resulting drive current is therefore 10 mA output to a drive node 84 to the water heater 10.

With continued reference to FIG. 2, the enabled circuit 42 includes a third switch 86 that, when activated, enables the drive circuit 38. An enable node 88 electrically couples the control circuitry 44 with the third switch 86 (e.g., transistor). When the control circuitry 44 provides the enable signal along the enable node 88 (e.g., a voltage), the third switch 86 is energized and a current pathway is formed through the first resistor 78, as well as a fourth resistor which can have a substantially higher resistance than the first, second, or third resistors 82. When the control circuitry 44 does not provide the enable signal, the input voltage to the drive circuit 38 will not result in an output current due to there being no current flowing through the first resistor 78. In this way, the control circuitry 44 can selectively enable and disable charging of the water heater 10. It is contemplated that the third switch 84 can be configured to operate in an inverse manner such that the control circuitry 44 can alternatively provide a “disable” signal. In this case, the switch 84 acts as a “normally closed” switch.

The detection circuit 40 includes a third voltage divider 90 between the drive node 84 and ground 26. A monitor node 92 electrically couples to the third voltage divider 90 and the control circuitry 44. The detection circuit 40 includes at least one smoothing capacitor 94, as well as an electro-static discharge (ESD) protector. A second supply voltage 46 electrically couples with the ESD protector 96. The ESD protector 96 limits current draw to the control circuitry 44 on the monitor node 92.

Referring now to FIG. 3, exemplary plots 100-106 of electrical signals across time demonstrate operation of the cathodic protection circuitry 20 of FIG. 2. As demonstrated in a first plot 100, a PWM signal is applied by the control circuitry 44 at a first duty cycle (e.g., 50%). For example, the PWM signal may be a 3.3V PWM signal at 10 kHz. A corresponding input voltage (third plot 104) is output by the DAC 56 commensurate with the PWM signal while the enable signal is high (e.g., during a first time T1), as demonstrated in the second plot 102. A resulting drive voltage (e.g., voltage of the drive node 84 when the current is being applied) output by the drive circuit 38 is also generated due to overlap of the PWM signal and the enable signal. When the enable signal is dropped, as shown in the second plot 102, the input voltage and drive voltage are each nullified as well, as no current is applied to the anode 18. During this period (e.g., second time T2), and as shown in the fourth plot 106, the control circuitry 44 measures an off-state voltage of the water heater 10 (e.g., a charge of the tank 12) and compares the off-state voltage to a target voltage. For example, the control circuitry 44 can calculate a difference, or normalized error E_N, in the target voltage and the off-state voltage. Based on the magnitude and polarity of the normalized error E_N, the control circuitry 44 can adjust the PWM signal higher or lower to approach the target voltage as shown on the right side 32 of the plot 100 in which the duty cycle was increased due to the off-state voltage being below the target voltage.

In some examples, the duty cycle of the cathodic protection circuit 2 refers to a sum or convolution of the enable signal and the PWM signal—that is, the frequency at which the drive current is applied vs. not applied. In these examples, this frequency represented as an effective duty cycle can be at least 90%. In still further examples, the effective duty cycle can be 95%. In still other examples, the effective duty cycle can be at least 98%. In some examples, the effective duty cycle is at least 99%. By having higher effective duty cycles, (e.g., a high ratio of time for applying the drive signal compared vs. time for measuring the off-state voltage), there is more time to apply current and enhance protection of the water heater 10. In some examples, the duration in which the drive circuit 38 is disabled is less than 10 milliseconds (ms) for each measurement. In some examples, the time in which the drive circuit 38 is disabled is approximately 1 ms.

Referring now to FIG. 4, a method 400 for cathodically protecting a tank 12 of a water heater 10 using an anode 18 includes electrically coupling the anode 18 to cathodic protection circuitry 20 at step 402. For example, a conductor of the anode 18 can electrically connect with the positive terminal 34, and thus the drive node 84, of the cathodic protection circuitry 20. Similarly, the tank 12 can be electrically connected to ground 26 via a fastener 24, such as a bolt, contacting the steel of the wall 22, and a conductor being tied to a grounding port of a residential circuit breaker system.

At step 404, the method 400 includes repeatedly applying current and limiting application of current to the anode 18. The application of current to the anode 18 can occur during a first time T1 and limiting application of current to the anode 18 can occur during a second time T2. For example, when the PWM signal and the enable signal are both ON, current can be applied to the anode 18 via the drive node 84. The method 400 further includes measuring an electrical parameter representative of a charge of the tank 12 during the second time T2 at step 406. For example, the control circuitry 44 can read an off-state voltage of the anode 18 and thus determine a charge of the tank 12.

At step 408, the method 400 includes adjusting a level of the current applied to the anode 18 based on a value of the electrical parameter. For example, the control circuitry 44 can compare the off-state voltage to the target voltage to determine the normalized error E_N and increase or decrease the duty cycle of the PWM signal to achieve a proportional increase or decrease in constant current output to the anode 18.

Referring now to FIGS. 5 and 6, the control circuitry 44 can operate in a diagnostic mode in which the target voltage, or threshold voltage, is estimated. In general, the target voltage can correspond to an off-state charge of the tank 12 in which it is protected but not overprotected (e.g., generating hydrogen). Identification of the target voltage can be performed actively or passively. In some examples, the target voltage is preprogrammed and stored in the memory 52. In some examples, the target voltage is adjusted over time automatically to adjust for expected or measured changes, or wear, of the tank 12. For example, the need for a high drive voltage can indicate exposed steel or high conductivity of water 16. In the present example, the target voltage can be estimated actively by a diagnostic algorithm.

With particular reference to FIG. 5, there can be a functional relationship between the drive voltage and the drive current, as well as between the off-state voltage and the drive current. The functional relationships can generally be non-linear or linear and may be fitted by the control circuitry 44 to a curve 108 having a peak 110 at which an instantaneous slope of each of curve 108 abruptly changes. The drive voltage and the off-state voltage can have a proportional relationship to one another. For example, the drive voltage may be proportionally offset from the off-state voltage (e.g., have a consistent difference in voltage at the drive current). Accordingly, the control circuitry 44 can be configured to monitor the drive voltage during the first time T1 (when current is being applied) to estimate the target voltage.

As shown in the example presented in FIG. 5, the control circuitry 44 can apply a sequence of different drive currents and measure, or read, a drive current at each of the different drive currents. In this case, seven drive currents were applied in the diagnostic mode (e.g., seven points on the curve 108). A slope, or rate of change (in V/A) can be determined by the control circuitry 44 based on applying a linear model between each iteration of the drive currents as depicted. In some examples, the control circuitry 44 applies a non-linear model (e.g., polynomial fit, curve fit) to generate the estimate. The control circuitry 44 can store the different “rates” of change to determine the peak 110 corresponding to the most abrupt change. The peak 110 can refer to the point at which the greatest change between readings in consecutive adjacent drive voltages is detected, or the point at which there was the greatest change in the “slope,” as demonstrated in FIG. 5. Once the peak 110 of the drive voltage is estimated, the offset 112 can be applied by the control circuitry 44 to determine the target voltage (e.g., the off-state voltage) and, as a result, an updated target electrical current. For example, the control circuitry 44 can determine a relationship between the drive voltage and the value of the electrical parameter (e.g., the off-state voltage), adjust the peak 110 according to the relationship, and assign the target voltage to a voltage level of the peak 110. The adjustment by the offset can vary depending on the relationship. For example, there may be a linear or nonlinear relationship between drive voltage and off-state voltage.

Referring now to FIG. 6, the method 400 for cathodically protecting the tank 12 of the water heater 10 can further include the steps provided in the diagnostic mode described above. For example, the method 400 can include measuring a drive voltage applied to the anode 18 during the first time T1 at step 410, applying current to the anode 18 at a plurality of different current levels at step 412, measuring the drive voltage at each of the plurality of different current levels at step 414, estimating a functional relationship between the current and the drive voltage at step 416, and setting the target based on the functional relationship at step 418. As previously described, the functional relationship can include a curve 108 including a peak 110, or point of interest, in which the target current provides optimized protection to the tank wall 22 (e.g., limits generation of hydrogen due to overprotection).

In general, the cathodic protection circuitry 20 can provide enhanced corrosion-resistance in a power-efficient way.

According to one aspect of the present disclosure, a water heater includes a tank defining an interior for holding water, an anode extending into the interior, and cathodic protection circuitry electrically coupled with the anode. The cathodic protection circuitry is configured to repeatedly apply current and limit application of current to the anode., wherein the application of current to the anode occurs during a first time and limiting application of current to the anode occurs during a second time. The control circuitry is configured to measure an electrical parameter representative of a charge of the tank during the second time and adjust a level of the current applied to the anode based on a value of the electrical parameter.

According to another aspect of the present disclosure, the water heater includes a power source and a constant current circuit electrically interposing the power source and the anode, wherein the cathodic protection circuitry is configured to control the level of the current via a pulse-width modulated (PWM) signal and selectively enable the constant current source to control the application of the current via an enable signal separate from the PWM signal.

According to another aspect of the present disclosure, the electrical parameter is voltage.

According to another aspect of the present disclosure, the cathodic protection circuitry is configured to compare the value of the electrical parameter to a target, increase the level of current in response to the value being less than the target, and decrease the level of current in response to the value being greater than the target.

According to another aspect of the present disclosure, the cathodic protection circuitry is configured to measure a drive voltage applied to the anode during the first time.

According to another aspect of the present disclosure, the cathodic protection circuitry is configured to estimate at least one of a conductivity of the water and an area of unprotected steel of a wall of the tank based on at least one of the electrical parameters and the drive voltage.

According to another aspect of the present disclosure, the cathodic protection circuitry is configured to selectively operate in a diagnostic mode and, in the diagnostic mode, apply current to the anode at a plurality of different current levels, measure the drive voltage at each of the plurality of different current levels, estimate a functional relationship between the current and the drive voltage, and set the target based on the functional relationship.

According to another aspect of the present disclosure, the cathodic protection circuitry is configured to, in the diagnostic mode, identify a peak in the functional relationship.

According to another aspect of the present disclosure, the cathodic protection circuitry is configured to, in the diagnostic mode, determine a relationship between the drive voltage and the value of the electrical parameter, adjust the peak according to the relationship, and assign the target to a voltage level of the peak.

According to another aspect of the present disclosure, repeated application of the current is executed at a duty cycle of at least 90%.

According to another aspect of the present disclosure, a method for cathodically protecting a tank of a water heater using an anode includes electrically coupling the anode to cathodic protection circuitry, repeatedly applying current, and limiting application of current to the anode. The application of current to the anode occurs during a first time, and limiting application of current to the anode occurs during a second time. The method includes measuring an electrical parameter representative of a charge of the tank during the second time and adjusting a level of the current applied to the anode based on a value of the electrical parameter.

According to another aspect of the present disclosure, the method includes controlling the level of the current via a pulse-width modulated (PWM) signal and selectively enabling the constant current source to control the application of the current via an enabled signal separate from the PWM signal.

According to another aspect of the present disclosure, the method includes comparing the value of the electrical parameter to a target, increasing the level of current in response to the value being less than the target, and decreasing the level of current in response to the value being greater than the target.

According to another aspect of the present disclosure, the method includes measuring a drive voltage applied to the anode during the first time.

According to another aspect of the present disclosure, the method includes applying current to the anode at a plurality of different current levels, measuring the drive voltage at each of the plurality of different current levels, estimating a functional relationship between the current and the drive voltage, and setting the target based on the functional relationship.

According to another aspect of the present disclosure, the method includes identifying a peak in the functional relationship.

According to another aspect of the present disclosure, the method determining a relationship between the drive voltage and the value of the electrical parameter, adjusting the peak according to the relationship, and assigning the target to a voltage level of the peak.

According to another aspect of the present disclosure, a cathodic protection circuit for a water heater includes a constant current circuit electrically coupled with an anode of the water heater, a detection circuit, and an enable circuit. Control circuitry is configured to selectively and repeatedly enable, during a first time, and disable, during a second time, the constant current circuit by controlling the enable circuit, measure, via the detection circuit, a voltage representative of a charge of a tank of the water heater during the second time, and adjust a level of the current applied to the anode based on a value of the electrical parameter.

According to another aspect of the present disclosure, the control circuitry is configured to apply current at a plurality of different current levels, measure a drive voltage at each of the plurality of different current levels, estimate a functional relationship between the current and the drive voltage set a target based on the functional relationship, and compare the voltage to the target voltage during each second time to determine the adjustment.

According to another aspect of the present disclosure, repeated enabling of the constant current circuit is executed at a duty cycle of at least 95%.

It will be understood by one having ordinary skill in the art that construction of the described disclosure and other components is not limited to any specific material. Other exemplary embodiments of the disclosure disclosed herein may be formed from a wide variety of materials, unless described otherwise herein.

It is also important to note that the construction and arrangement of the elements of the disclosure as shown in the exemplary embodiments is illustrative only. Although only a few embodiments of the present innovations have been described in detail in this disclosure, those skilled in the art who review this disclosure will readily appreciate that many modifications are possible (e.g., variations in sizes, dimensions, structures, shapes, and proportions of the various elements, values of parameters, mounting arrangements, use of materials, colors, orientations, etc.) without materially departing from the novel teachings and advantages of the subject matter recited. For example, elements shown as integrally formed may be constructed of multiple parts or elements shown as multiple parts may be integrally formed, the operation of the interfaces may be reversed or otherwise varied, the length or width of the structures and/or members or connector or other elements of the system may be varied, the nature or number of adjustment positions provided between the elements may be varied. It should be noted that the elements and/or assemblies of the system may be constructed from any of a wide variety of materials that provide sufficient strength or durability, in any of a wide variety of colors, textures, and combinations. Accordingly, all such modifications are intended to be included within the scope of the present innovations. Other substitutions, modifications, changes, and omissions may be made in the design, operating conditions, and arrangement of the desired and other exemplary embodiments without departing from the spirit of the present innovations.

It will be understood that any described processes or steps within described processes may be combined with other disclosed processes or steps to form structures within the scope of the present disclosure. The exemplary structures and processes disclosed herein are for illustrative purposes and are not to be construed as limiting.