Patent Publication Number: US-11639757-B2

Title: Systems and methods for operating a ball valve

Description:
RELATED APPLICATION 
     This application claims the benefit of U.S. Provisional Application No. 63/045,502, filed Jun. 29, 2020, and titled SYSTEMS AND METHODS FOR OPERATING A BALL VALVE, the entirety of which is incorporated herein by reference. 
    
    
     INTRODUCTION 
     Valves provide for the control of fluid. One type of valves available is a ball valve. A ball valve controls the flow of a fluid, such as a liquid or a gas, through the use of a rotary ball having a bore through the ball. In one position of the ball, the bore is aligned with the pipe or tubing, which allows for fluid to flow through the valve. When the ball is turned 90 degrees (e.g., a quarter turn), flow of the fluid through the valve is blocked. Control of a ball valve may be performed by a manual control, such as a lever, or by other controls, such as electric or pneumatic controls. 
     It is with respect to this general technical environment that aspects of the present technology disclosed herein have been contemplated. Although a general environment has been discussed, it should be understood that the examples described herein should not be limited to the general environment identified herein. 
     SUMMARY 
     Aspects of the disclosure relate to providing a pulse control to a ball valve to reduce the amount of torque required to adjust the position of the ball valve. In an aspect, the technology relates to a method for reducing resistance of a ball valve. The method includes generating a pulse having a duration and a polarity; providing the pulse to an actuator configured to rotate a ball of the ball valve; and rotating, by the actuator, the ball of the ball valve by an amount based on the duration of the pulse and a direction based on the polarity of the pulse, wherein the ball valve does not change state after rotation of the ball. 
     In an example, the method further includes determining a position of the ball valve; and based on the determined position of the ball valve, setting the polarity of the pulse. In another example, the position of the ball valve is fully closed; and the polarity is set to cause the actuator to rotate the ball towards the fully open position. In a further example, the position of the ball valve is fully open; and the polarity is set to cause the actuator to rotate the ball towards the fully closed position. In yet another example, the duration is set based on inputs received from input components provided in valve circuitry connected to the ball valve. In still another example, the actuator rotates the ball less than five degrees. In still yet another example, the method further includes providing, to the actuator, a subsequent pulse having a polarity opposite the polarity of the pulse. In another example, the pulse is generated locally by valve circuitry connected to the ball valve. 
     In another aspect, the technology relates to a method for reducing resistance of a ball valve. The method includes generating a series of pulses, including a first pulse and a second pulse. The first pulse has a first duration and a first polarity; and the second pulse has a second duration and a second polarity, wherein the second polarity is opposite the first polarity. The method further includes transmitting the series of pulses to an actuator configured to control the position of a ball of the ball valve. 
     In another example, the first pulse and the second pulse are provided as a first pulse pair. In a further example, the first duration is the same as the second duration. In yet another example, the series of pulses includes a second pulse pair that includes a third pulse and a fourth pulse; and the second pulse pair is provided a period (P) after the first pulse pair is provided. In still another example, the second pulse is provided a time interval (T) after the first pulse is provided, wherein a ratio between the time interval (T) and the period (P) is less than 1/100. In still yet another example, the period (P) is at least one hour. In yet a further example, the method further includes receiving, by the actuator, the series of pulses; and rotating, by the actuator, the ball of the ball valve according the series of pulses. In another example, the series of pulses are generated and transmitted by a utility control device located remotely from the ball valve. In yet another example, the method further includes transmitting, by the utility control device, the series of pulses to at least one additional ball valve. 
     In another aspect, the technology relates to a system that includes a ball valve including a ball having a bore; a pulse generator configured to generate a series of pulses; and an actuator configured to rotate the ball of the ball valve based on the series of pulses generated by the pulse generator. In an example, the system further includes a utility control device that is located remote from the ball valve, wherein the utility control device includes the pulse generator. In another example, the system further includes input components for receiving inputs to alter characteristics of the series of pulses. 
     In another aspect, the technology relates to a method for rotating a ball valve having a ball and an actuator. The method includes applying, at a first time, an open signal to the actuator of the ball valve when the ball valve is in a fully closed state; receiving, at a second time, a first signal from a close limit switch of the ball valve, the first signal indicating the ball has begun rotation; receiving, at a third time, a second signal from an open limit switch of the ball valve, the second signal indicating the ball has rotated into the fully open position; based on the first time and the second time, determining a delay time; based on the second time and the third time, determining a rotation time; based on the delay time, the rotation time, and a number of degrees the ball rotated from the fully closed state to the fully open state, determining a pulse duration; generating a pulse having the determined pulse duration; providing the pulse to the actuator; and rotating, by the actuator, the ball of the ball valve by an amount based on the duration of the pulse. In an example, the ball valve does not change state after rotation of the ball. 
     This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. Additional aspects, features, and/or advantages of examples will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the disclosure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The following drawing figures, which form a part of this application, are illustrative of aspects of systems and methods described below and are not meant to limit the scope of the invention in any manner, which scope shall be based on the claims. 
         FIG.  1 A  depicts an example system for controlling a ball valve. 
         FIGS.  1 B- 1 F  depict various positions of the ball valve. 
         FIG.  2 A  depicts an example series of electrical pulses. 
         FIG.  2 B  depicts another example series of electrical pulses. 
         FIG.  3    depicts an example system for controlling a plurality of ball valves. 
         FIG.  4    depicts an example method for controlling a ball valve. 
         FIG.  5    depicts an example method for controlling multiple ball valves. 
         FIG.  6    depicts an example method for calibrating a control system for a ball valve. 
     
    
    
     DETAILED DESCRIPTION 
     As discussed above, a ball valve controls the flow of fluid through the valve bay rotating a ball that has a bore through the ball. Traditionally, rotation of the ball was controlled manually. Newer methods allow for electronic control of the ball valve. To open or close the ball valve, some amount of torque is required to rotate the ball. With electronic controls, the amount of torque that may be applied by an electronic actuator is typically limited. The torque applied by the electronic actuator is generally described or rated in two ways. The first torque rating is the “breakaway torque,” which is the amount of torque required to start the rotation or unseat the ball. The second torque rating is the “run torque,” which is the amount of torque needed to keep rotating. The breakaway torque is often higher than the run torque. Increasing the breakaway torque rating of an electric actuator becomes increasingly difficult and expensive, particularly where there are size limitations of the actuator. 
     When ball valves are put in use, the longer a ball valve stays in a particular position, the more likely the ball valve is to get “stuck,” causing the resistance to opening or closing the valve to increase. When the ball valve “sticks,” a higher breakaway torque is required to rotate the ball valve from its current position. The effect of the sticking may also be made worse depending on the type of fluid flowing through the ball valve. For instance, some fluids are more likely to cause calcifications that may increase the resistance of the valve. In some cases, the sticking effect causes the breakaway torque to increase to a point that the electronic actuator is no longer able to rotate the ball of the ball valve. The sticking effect of ball valves has been considered one of the biggest drawbacks for ball valves, particularly as compared to solenoid-based valves. Ball valves, however, have several other advantages over solenoids, such as there is no power required to hold a ball valve open or closed, there is little to no noise involved with a ball valve, and debris tends to be less of an issue. Accordingly, if the sticking effect could be alleviated or eliminated, ball valves could become more efficient and provide a better option in fluid control technologies. 
     The present technology provides solutions to reduce the sticking problem associated with ball valves, along with solutions to other problems. To resolve or reduce the effect of the sticking problem, the present technology provides an electric pulse to the ball valve that causes the electronic actuator to slightly rotate the ball of the ball valve. By slightly moving the ball, the sticking effect is reduced or eliminated. For instance, by rotating the ball of the ball valve, the amount of breakaway torque required to rotate the ball remains lower and within the range of the electronic actuator. The pulse may be provided at different intervals and for different durations depending on the implementation and use of the ball valve. For example, the pulse may be provided hourly, daily, weekly, or in other periods as appropriate for the particular implementation. The pulse may also have a duration that causes the electronic actuator to rotate the ball by one or two degrees or more. 
     In addition, in some instances where the valve is normally closed, the pulse may cause the valve to slightly open to allow some amount of fluid to flow through the valve. Such an implementation may be preferable to prevent stagnant fluid, which in turn helps prevent freezing or the growth of bacteria, such as  Legionella  bacteria that may cause Legionnaire&#39;s disease. In other implementations where the valve is normally closed, the pulse causes a smaller rotation of the ball that results in the valve still remaining closed. Such an implementation may be preferable where the valve is controlling natural gas or other types of fluids where any type of leak is undesirable. 
     The pulse may be generated locally by valve circuitry or electronics that are directly attached to the valve itself. For example, the electronic control circuitry connected to the electronic actuator may include a timer configured to generate the pulse at the appropriate times and for the appropriate durations. Thus, the valve assembly or system effectively becomes a non-sticking valve that may also have additional benefits, such as preventing freezing and bacteria growth. In other examples, the pulse may be generated remotely from a control system. The control system may be configured to control a plurality of valves that are distributed in a variety of physical locations. Accordingly, different pulse timings and durations may be generated for different valves based on the particular use of each valve. 
       FIG.  1 A  depicts an example system  100  for controlling a ball valve  102 . The system  100  includes the ball valve  102  and valve circuitry  114  for controlling the ball valve  102 . The ball valve  102  is shown as a partial cross section. The ball valve  102  includes a valve body  104  that houses a ball  106  having a bore  108 . The ball  106  rests on valve seats  110 . Rotation of the ball  106  is controlled via a valve stem  112 . In the example configuration depicted, the ball valve  102  is in an open position to allow fluid to flow through the ball valve  102 . The ball valve  102  is in an open position when the bore  108  of the ball  106  is at least partially aligned with the fluid and/or pipe to allow for the fluid to flow through the valve  102 . The ball  106  may be rotated by rotation of the valve stem  112 . For example, the valve stem  112  may be used to rotate the ball  106  a quarter turn (e.g., 90 degrees) to close the valve  102 . When the ball  106  is rotated 90 degrees, the bore  108  is perpendicular to the flow of fluid, and thus, no fluid passes through the valve  102 . 
     When the ball  106  is in the 0-degree position, the valve  102  is fully open. When the ball  106  is in the 90-degree position, the valve  102  is fully closed. The ball  106  may also be positioned at different angles between 0-90 degrees to alter the amount of fluid that passes through the valve  102 . For instance, when the ball  106  is in a 45-degree position, less fluid may pass through the valve  102  than when the ball  106  is in the 0-degree position. In some configurations of the ball valve  102 , there may be range of degrees where the valve still remains fully closed. For instance, the valve  102  may remain fully closed (e.g., preventing fluid flow) when the ball  106  is positioned between 85-90 degrees. The valve  102  remains closed because no portion of the bore  108  is aligned or exposed to the fluid. The amount of rotation from the 90-degree position that is possible while still having the valve  102  remain closed changes depending on the configuration of the valve  102 , the ball  106 , and the bore  108 . Although examples described herein include rotating the ball  106  between 0 and 90 degrees, it will be appreciated that in other examples, the valve  102  may be configured to rotate the ball  106  past the 90-degree position. For example, the ball may rotate fully through 360 degrees with various degrees of opening and closing of the valve  102 , depending on the particular configuration of the valve  102 , the ball  106 , and the bore  108 . Additional features regarding the different states of the valve  102  are discussed further below with reference to  FIGS.  1 B- 1 F . 
     The valve stem  112  is controlled electronically by the valve circuitry  114 . The valve circuitry  114  may include an actuator  116 , a pulse generator  118 , and input/output (I/O) circuitry  120 . The actuator  116  physically rotates the valve stem  112  to cause the ball  106  to rotate. The actuator  116  may include an electric motor that converts electric energy into rotational mechanical energy to rotate the valve stem  112  and the ball  106 . The actuator  116  may be a two-point actuator, a three-point actuator, or a control-loop actuator, among other types of actuators. A two-point actuator generally includes three input wires or leads—a positive wire, a negative wire, and a control wire. When current flows over the control wire, the valve  102  will close or open depending on the direction of the current flow (either through the positive wire or the negative wire). A two-point or three-point actuator is generally used to fully open or fully close the valve  102 . A control-loop actuator may be a 4-20 mA control actuator, among other types. In a control-loop actuator, the position of the ball  106  may be set and the position of the ball  106  may be provided or transmitted. Thus, the position of the ball  106  may be set, and the position may be known or determined. The actuator  116  may also include a modulating actuator control or digital positioning system (DPS) to control the position of the actuator  116  and the valve stem  112 . 
     The actuator  116  may also include one or more limit switches. The limit switches define end positions for actuator  116 . When the actuator  116  reaches a limit switch, power is removed, and the actuator  116  stops moving. For example, a first limit switch may be at the 0-degree position and a second limit switch may be at the 90-degree position. The limit switches may also generate signals that indicate the position or state of the valve  102 . 
     The signals for controlling the actuator  116  may be generated locally at the valve circuitry  114  via the I/O circuitry  120  and/or generated remotely and provided via an input wire or wires  122 . The I/O circuitry  120  may include various components for receiving input to control the valve  102  and/or providing output information about the state of the valve  102 . The input components may include buttons, wheels, switches, etc. The input components may allow a user to set a position and/or state of the valve  102 , such as fully open, fully closed, or anywhere in between. The input components may also allow for a user to set characteristics of a pulse, as discussed further below. The output components may include dials, displays (such as a seven-segment display or the like), meters, etc. The output components may convey the current position of the valve  102 . In some examples, the output components may also convey the presently set characteristics of the pulse, as discussed further below. 
     In other examples, the actuator  116  may be controlled remotely in addition to, or alternatively to, being controlled locally. A control signal may be generated by a utility control device that is located remotely from the valve  102 , as discussed further below with respect to  FIG.  3   . The control signal may be received by the actuator via input wire or wires  122 . The control signal indicates a desired position for the valve  102 , or more specifically, the position of the ball  106  within the valve  102 . In other examples, the actuator  116  may receive the control signal via a wireless connection. For instance, the valve circuitry  114  may include wireless communication components that allow for transmission and receipt of wireless communications. The wireless communication components may include radio-frequency (RF) components, such as BLUETOOTH-based components, WIFI-based components, ZIGBEE-based components, among others. In such examples, the control signal may be received by the wireless components and converted into a local control signal that is provided to the actuator  116 . The actuator  116  may also provide position information about the current position of the ball  106  to the wireless components that in turn transmit the position information to a remote device, such as a utility control device. 
     The pulse generator  118  of the valve circuitry  114  operates to locally generate an electric pulse that is provided to the actuator  116  to slightly move or rotate the ball  106  to prevent the ball  106  from sticking. The pulse generated from the pulse generator  118  may be described in terms of its characteristics, such as duration, amplitude, and polarity. The duration of the pulse may control the amount of rotation that actuator  116  rotates the ball  106 . For example, the pulse duration may correspond directly to a number of degrees that the actuator  116  rotates the ball  106 . The exact relationship between pulse duration an amount of rotation will vary based on the configuration of the valve  102  and the actuator  116 . The amplitude of the signal, such as the voltage level of the signal, may correspond to the amount of force exerted on the valve stem  112  by the actuator  116 . The polarity of the signal corresponds to the direction of rotation. For example, a positive polarity may cause the ball  106  to rotate towards the closed position (e.g., towards the 90-degree position) and a negative polarity may cause the ball  106  to rotate towards the open position (e.g., towards the 0-degree position). In other examples, the polarities may be switched depending on the wiring configuration (e.g., positive polarity may open the valve and negative polarity may close the valve). The pulse may be generated by the pulse generator  118  through a variety of techniques or components. For example, the pulse generator  118  may include a 555 timer, or similar integrated-circuit (IC) device, multivibrators, or other similar components that can be configured to generate a pulse. The 555 timer, along with other electronic components (e.g., resistors, inductors, capacitors, etc.) may be configured to produce a pulse having a desired duration, polarity, and amplitude. For example, a first variable resistor may be altered to change the pulse duration and a second variable resistor may be altered to change the frequency of the pulses. The pulse generator  118  may also or alternatively include a microcontroller, microprocessor, and/or memory configured or programmed to generate a pulse with the desired characteristics, such duration, polarity, and amplitude. 
     The pulse generator  118  may also generate a series of pulses automatically based on a set schedule and frequency. The rate at which the pulses are generated may be referred to as the frequency of the pulse. The frequency of the pulse may be on the order of minutes, hours, days, weeks, or months, depending on the valve  102  and the implementation of the valve  102 . For example, for a valve controlling a liquid that may be more prone to causing the valve  102  to stick, a pulse may be generated every hour. For a valve controlling a gas that may be less prone to causing the valve to stick, a pulse may be generated every day or every week. In other examples, the pulse may also be generated by a manual selection of an input component to generate a pulse. 
     The duration, polarity, amplitude, and/or frequency of the series of pulses may be preset into firmware or the electronic components of the pulse generator  118 . In other examples, the duration, polarity, amplitude, and/or frequency of the series of pulses may be based on inputs received from the input components of the I/O circuitry  120 . In some examples, the input components may include access to a variable resistor or switch(es) that may be used to alter the duration, polarity, amplitude, and/or frequency of the series of pulses. In other examples, the input components may be configured to allow a user to select a direction and a number of degrees to open or close the valve  102 . The input components may also include options for selecting the frequency that the pulses are generated. 
     In other examples, a plurality of presets may be available that correspond to the different possible implementations for the valve  102  and the type of valve  102 . For instance, a series of presets may be presented for selection via an input component (e.g., dial, switch, button, etc.). The preset may correspond to a “liquid” setting or a “gas” setting. Finer presets may also be presented that are based on the type of liquid or gas, the amount of flow of the fluid, among other types of implementation details. Presets may also be based on whether any flow is desired through the valve  102  when the valve  102  is pulsed. Once a preset is selected, the duration, polarity, amplitude, and/or frequency of the pulses may be set according to the preprogrammed preset. 
       FIGS.  1 B- 1 F  depict various positions of the ball valve  102 . More specifically,  FIGS.  1 B- 1 F  depict a top view of the ball valve  102  depicted in  FIG.  1 A . The valve  102  may be in three general states: (1) fully open; (2) partially open (or partially closed), and (3) fully closed.  FIGS.  1 B- 1 C  depict the valve  102  in the fully open position. In  FIG.  1 B , the ball  106  is in the 0-degree position. A bore axis  109  is represented in  FIGS.  1 B- 1 F  to more easily see the position of the ball  106  and the bore  108 . As can be seen, when that ball  106  is the 0-degree position, the bore axis  109  is aligned with the valve body  104  and the flow of fluid through the valve  102 . In some examples, the ball  106  may be rotated slightly and may still remain in the fully open position. For example,  FIG.  1 C  depicts the ball  106  being rotated 5 degrees, from the 0-degree position, towards the fully closed position. The position of the ball  106  in  FIG.  1 C  is still considered fully open because the entire opening of the bore  108  is still exposed to the flow of fluid through the valve  102 . 
     Once the ball  106  is rotated to a point where a portion of opening of the bore  108  is not open to the flow of fluid through the valve  102 , the valve  102  is no longer in the fully open state. Rather, the valve  102  is then in a partially open state. The partially open state may also be referred to as the partially closed state.  FIG.  1 D  depicts the valve  102  in the partially open or partially closed state. In  FIG.  1 D , the ball  106  has been rotated by 30 degrees from the 0-degree position towards the fully closed position. At the 30-degree position, only a portion of the opening of the bore  108  is exposed to the flow of fluid. 
     Once the ball  106  is rotated to a point where no portion of the bore  108  is exposed to the flow of fluid, the valve  102  is in the fully closed state.  FIG.  1 E  and  FIG.  1 F  depict the valve  102  in the fully closed state. In  FIG.  1 E , the ball  106  has been rotated 85 degrees from the 0-degree position towards the 90-degree position. At the 85-degree position, no portion of the opening of the bore  108  is exposed to the flow of fluid. Thus, the when the ball  106  is in the 85-degree position, the valve  102  is in the fully closed state.  FIG.  1 F  depicts the valve  102  with the ball  106  in the 90-degree position. As should be appreciated, there are multiple positions of the ball  106  where the valve  102  may be in the fully closed state, the fully open state, or the partially open state. The range of angular positions that correspond to each state may vary between different valves and valve configurations. 
     In some examples, the pulses described herein may cause the ball  106  to rotate but still remain in the same state. For example, the ball  106  may begin at the 90-degree position and a pulse may cause the ball  106  to move to the 85-degree position. In such an example, the ball  106  begins and ends in the fully closed state. 
       FIG.  2 A  depicts an example series of pulses  202 - 208 . The pulses  202 - 208  are plotted on a graph having a y-axis of voltage and an x-axis of time. The pulses and graphs are not drawn to scale. Each of the pulses  202 - 208  has a duration (D) and an amplitude (A). Depending on the configuration of actuator and the valve, the duration (D) may be in the range of a few milliseconds to a few seconds. In some examples, the pulse duration may be between 50 ms to 500 ms. Pulse durations for desired amounts of rotations may be determined from a calibration process discussed in further detail below with reference to  FIG.  6   . Also depending on the configuration of the actuator and the valve, the amplitude of the pulse may be in the range of a few volts (e.g., 9 V, 12 V, etc.) to over a hundred volts (e.g., 110 V, 120 V, 220 V, etc.). The pulses  202 - 208  are separated in time by a period (P). Depending on the implementation, the period may be on the order of minutes, hours, days, weeks, or months. In one example, the period may be less than or equal to 24 hours, which corresponds to a frequency of once per day. In some examples, the duration, period, and/or amplitude of the pulse may remain constant, and in other examples, the duration, period, and/or amplitude of the pulse may vary. 
     In the example depicted, the first pulse  202  and the third pulse  206  have a positive polarity, and the second pulse  204  and the fourth pulse  208  have a negative polarity. Such a pulse pattern may repeat after the fourth pulse  208  for any total amount of time, such as the lifetime of the valve. 
     The pulse pattern depicted in  FIG.  2 A  may be appropriate for reducing resistance of a valve (e.g., preventing the valve from sticking) that is normally in an open position, where a positive pulse causes the ball to move slightly towards the closed position. In such an example where the period is one day, the first pulse  202  may occur on a first day to slightly rotate the ball from the open position (e.g., 0-degree position) towards the closed position (e.g., the 90-degree position). The amount of rotation corresponds to the duration of the first pulse  202 . The amount of rotation may be 2 degrees. In other examples the amount of rotation may be less than 15 degrees, less than 10 degrees, less than 5 degrees, less than 4 degrees, less than 3 degrees, or less than 2 degrees. In some valve configurations, rotating the ball by 2 degrees from the fully open position may not result in any substantial impediment to the flow through the valve. For example, the valve may begin in the fully open state and remain in the fully open state after rotation. As such, the ball may be left in the 2-degree position for the remainder of the period. At the end of the first period, the second pulse  204  is generated. The second pulse  204  has the same duration and amplitude as the first pulse  202 , but the second pulse  204  has a negative polarity rather than a positive polarity. Accordingly, the negative second pulse  204  causes the actuator to rotate the ball in the opposite direction. In the present example, the second pulse  204  causes the actuator to rotate the ball back to the fully open position. For instance, the second pulse  204  may cause the ball to rotate from the 2-degree position that resulted from the first pulse  202  back to the 0-degree position. 
     The pulse pattern depicted in  FIG.  2 A  may be appropriate for reducing resistance of a valve that is normally in a closed position. In an example where a negative pulse causes the actuator to rotate the ball towards the open position, the pulse pattern may begin with the second pulse  204 . In such an example, when the negative second pulse  204  is generated and received by the actuator, the actuator rotates the ball slightly towards the fully open position. For example, the second pulse may cause the ball to rotate 2 degrees from the 90-degree position towards the fully open position (e.g., the 0-degree position) resulting in the ball being in an 88-degree position. The position of the ball after the second pulse  204  may still cause the valve to be in the fully closed state and prevent all flow of fluid because no part of the bore of the ball is aligned or exposed to the flow of fluid. Accordingly, the ball may remain in the 88-degree position for the remainder of the period while still preventing all flow of fluid. Thus, the second pulse  204  prevents sticking of the valve while also preserving the full functionality of the valve. At the end of the period starting from the second pulse  204 , the third pulse  206  is generated and received by the actuator. The third pulse  206  causes the actuator to rotate the ball from the slightly open position back to the fully closed position. Continuing with the present example, the third pulse  206  may cause the ball to rotate from the 88-degree position to the 90-degree position. 
       FIG.  2 B  depicts another example series of pulses  212 - 218 . The pulse series is provides as a series of “pulse pairs.” The pulse pairs include a positive pulse and a negative pulse in sequence with one another offset by a time interval (T). In examples where pulse pairs are implemented, the period (P) is measured from the beginning of the each of the pulse pairs. For instance, in the example depicted, the period (P) is measured from the beginning of the first pulse  212  to the beginning of the third pulse  216 . The time interval (T) is substantially shorter than the period (P). In some examples, the time interval (T) may be on the order of milliseconds or seconds. In such examples, the ratio of the time interval (T) to the period (P) (the “TP Ratio”) may be less than 1/50,000. In other examples, the TP ratio may be less than 1/100, less than 1/1,000, less than 1/10,000, or less than 1/100,000. While the pulse duration (D) of the pulses  212 - 218  is depicted as longer than the time interval (T), in many examples, the time interval (T) may be longer than the pulse duration (D). 
     The pulse pattern of pulse pairs depicted in  FIG.  2 B  may be appropriate for a valve in a closed position where some amount of fluid leak through the valve is desired. As one example, where the valve is controlling the flow of water, some flow of water through the valve may be desired to prevent bacterial growth or freezing. The amount of water flow may be based on the particular system in which the valve is implemented. For example, a small drip of water for some time may be appropriate in some systems, whereas a more substantial rush of water for a short time may be appropriate in some systems to flush out a portion of the system, such as flushing out humidifiers or evaporative coolers. In either example, it may be useful to have controlled drainage to catch or handle water that is released through the valve. 
     To achieve the result of an intermittent flow through the valve, the pulse pairs first open the valve and then close the valve after the time interval (T). For example, the first pulse pair in the series of pulses includes a first pulse  212  and a second pulse  214 . The first pulse  212  has a positive polarity, and the second pulse  214  has a negative polarity. When the first pulse is generated and received by the actuator, the actuator rotates the ball to a partially open position to allow some fluid to flow through the valve. The amount of rotation may be based on the desired amount of flow through the valve. For instances where a high flow is desired, such as to intermittently flush out a system, the amount of rotation will be greater, and thus the pulse duration may be greater. The rotation may include rotations as large as a rotation to cause the ball to move to the fully open position. For instances where a low flow is desired, the amount of rotation will be smaller, and thus the pulse duration will be smaller. Subsequent to the first pulse  212 , the ball remains in the open position for the time interval (T). The time interval (T) may be selected based on the amount of rotation caused by the first pulse  212 . For instance, where a large rotation occurs, and thus a high flow occurs, the time interval (T) may be relatively short (e.g., a few seconds or less). In examples where a small rotation occurs, and thus a low flow or drip occurs, the time interval may be longer (e.g., 10 seconds or more). At the end of the time interval (T), the second pulse  214  is generated and provided to the actuator. The second pulse  214  causes the actuator to rotate the ball back towards the fully closed position and end the flow of fluid through the valve. In some examples, the second pulse  214  has the same duration and amplitude as the first pulse  212  to cause the ball to rotate back to the position from which it started prior to the first pulse  212  being generated. For instance, the second pulse  214  may cause the ball to return to the fully closed position. 
     The use of pulse pairs may also be used when the valve is in the fully open position. In such an example, the polarity of the pulse pairs may be switched such that first pulse in the pulse pair has a negative polarity and the second pulse in the pulse pair has a positive polarity. Accordingly, the pulse pair causes the ball to rotate towards a closed position and then back to the fully open position. 
     While only two pulse patterns have been discussed in  FIGS.  2 A- 2 B , it should be appreciated that many more pulse patterns are possible depending on the desired results and configurations of the valve and the valve circuitry. For example, while the examples of  FIGS.  2 A- 2 B  illustrate consecutive pulses having opposite polarity, it is possible that in some examples multiple pulses are generated having the same polarity followed by multiple pulses in the opposite polarity. In addition, while the pulse patterns in  FIGS.  2 A and  2 B  are primarily discussed with respect to their applications to normally closed and normally open valves during particular situations or implementations, the pulse patterns may be applied to a valve that is in any position. Further, while the pulses are depicted as square-wave pulses, the pulses may be of any shape suitable to cause the desired rotation of the ball by the actuator. In addition, when referring to polarity of the pulses, the concept also includes providing pulses on different control lines with reference to a common wire. For example, in some implementations, the actuator may include a wire to receive a close signal, a wire to receive an open signal, and a common wire to allow current to flow. The polarity of the pulse may reference which wire the pulse is provided on. For example, a positive polarity pulse may reference a pulse that is provided on the close-signal wire, and a negative polarity pulse may reference a signal provided on the open-signal wire. In other examples, the polarity references may be switched. 
     In some examples, the actuator may include capacitors that are configured to automatically close the valve upon power being removed from the valve. In such valves, continuous power or a continuous open signal may be required to keep the valve in the fully open position. While the power is applied, a capacitor in the actuator charges and maintains a charge. When the power is removed (either intentionally or unintentionally) the charge in the capacitor is used by the actuator to rotate the valve back to the fully closed position. Accordingly, in such examples, the pulse to rotate the ball towards the open position is a pulse of power or a pulse of an open signal, similar to the pulses described above. No negative pulse, however, may be needed to return the ball back to the 0-degree position because upon cessation of the pulse of power, the capacitor discharges, which causes the ball to rotate back to the fully closed position. To help prevent sticking in the fully open position, the pulse to rotate the ball towards the closed position is a lack of power (or lack of open signal) rather than a pulse of opposite polarity. For instance, to rotate the ball a small amount (e.g., a few degrees) towards the closed position, power may be removed from the valve for a pulse duration. The removal of power may be considered an off pulse. For the duration of the off pulse, the capacitor partially discharges, which causes the ball to rotate towards the closed position. At the end of the off pulse, when power is reapplied, the capacitor recharges and the ball is rotated back into the fully open position. 
       FIG.  3    depicts an example system  300  for controlling a plurality of ball valve systems  302 - 308 . The ball valve systems  302 - 308  may each be controlled by a utility control device  310 . Each of the ball valve systems  302 - 308  may include some or all of the components of the system  100  described above with respect to  FIG.  1 A . For example, each of the ball valve systems  302 - 308  may include a ball valve and valve circuitry. 
     The control signals and pulses provided to the ball valve systems  302 - 308 , however, may be generated from the utility control device  310 . The utility control device  310  may include a microprocessor, memory, and/or a microcontroller configured to perform the operations described herein. The utility control device  310  may also include any of the components of the valve circuitry described above. One example of a device that may be modified to perform the functions of the utility control device  310  is the control panel described in U.S. Pat. No. 9,683,911, which is incorporated herein by reference in its entirety. 
     Each of the pulse generation operations discussed above as being performed by the pulse generator in the valve circuitry may be performed by the utility control device  310 . The general control signals for opening and closing the ball valve systems may also be generated by the utility control device. The utility control devices may also include the same input/output (IO) components of the valve circuitry described above. Accordingly, the duration, amplitude, polarity, and/or frequency of a series of pulses may be set at the utility control device  310 . The series of pulses may then be transmitted from the utility control device  310  to the ball valve systems  302 - 308 . The transmission may be performed via a wired or wireless connection. 
     The pulses may be configured individually for each of the ball valve systems  302 - 308  that are in communication with the utility control device  310 . For example, characteristics for a series of pulses transmitted to the first ball valve system  302  may be different than the characteristics for a series of pulses transmitted to the second ball valve system  304 . Such a customization may be useful where the ball valve systems  302 - 308  are implemented in different conditions or are configured differently. For instance, the same series of pulses may not be appropriate for both a ball valve system that is controlling the flow of natural gas and a ball valve system controlling the flow of water. 
       FIG.  4    depicts an example method  400  for controlling a ball valve. Operations of method  400  may be performed by any of the components described herein or a combination of such components. For instance, some operations may be performed by valve circuitry that is connected or attached to the ball valve. Some operations may also or alternatively be performed by a utility control device remotely located from the ball valve. 
     At operation  402 , a position of the valve may be determined. The position of the valve may correspond to the position of the ball within the valve. The position may be determined based on signals provided by the actuator and/or by limit switches provided in the valve circuitry. For instance, in examples where the actuator is a control-loop actuator, the actuator may provide the position of the valve, or a signal corresponding to a position of the valve. In some examples, the limit switches may also provide positioning signals. For instance, a limit switch at the fully closed position may generate a signal, when the actuator triggers the limit switch, indicating that the valve is in the fully closed position. Similarly, a limit switch at the fully open position may generate a signal, when the actuator triggers the limit switch, indicating that the actuator is in the fully open position. 
     At operation  404 , pulse characteristics may be set or determined. The pulse characteristics include the pulse duration, amplitude, and/or polarity. The pulse characteristics may also include the frequency of pulse generation and/or the period (P) between pulses. One or more of the pulse characteristics may be based on the valve position determined in operation  402 . For example, the pulse polarity may be based on the determined valve position. In examples where the valve position is determined to be fully closed, the pulse polarity may be set to cause the actuator to rotate the ball of the valve towards the fully open position. In examples where the valve position is determined to be fully open, the pulse polarity may be set to cause the actuator to rotate the ball of the valve towards the fully closed position. In some examples, the pulse characteristics may also be based on input received from input components on the valve circuitry locally connected to the valve and/or input components of a utility control device. For instance, the duration of the pulse may be based on an input indicating the number of degrees that a user desires the ball of the valve to rotate or a setting indicating the purpose for which the valve is being used (e.g., gas, water, etc.). In some examples, at least one of the pulse characteristics may be preset when the valve circuitry is manufactured. 
     At operation  404 , a first pulse is generated based on the pulse characteristics. The first pulse may be generated by a pulse generator of the valve circuitry locally connected to the valve and/or by a pulse generator of a utility control device remotely located from the valve. As discussed above, generation of the first pulse may be initiated by a microprocessor, a microcontroller, or an IC circuit, among other possible components. 
     At operation  408 , the first pulse is provided to an actuator. In examples where the first pulse is generated locally, providing the first pulse to the actuator may including transmitting the first pulse over a wire or trace electrically connecting the pulse generator and the actuator. In examples where the pulse generator is located remote from the valve, the first pulse may be provided via a wired or a wireless connection. 
     At operation  410 , the actuator receives the first pulse and rotates the ball of the valve based on the characteristics of the first pulse. The actuator may rotate the ball by rotating a valve stem that connects the actuator and the ball, as discussed above. The actuator rotates the ball of the valve based on the duration of the first pulse, and the direction of the rotation is based on the polarity of the first pulse. The amount of force provided by the actuator may be based on the amplitude of the first pulse. In some examples, the amount of rotation may be small, such as less than five degrees. For example, the valve may be in the fully closed state prior to rotation and remain in the fully closed state after rotation. 
     At operation  412 , a second pulse is generated. The second pulse may be generated by same components that generated the first pulse. The second pulse may be generated after a period (P) from the time the first pulse was generated. The period (P) may be at least one hour or other time durations discussed herein. In other examples where the first pulse and the second pulse are a pulse pair, the second pulse may be generated a time interval (T) after the first pulse is generated. 
     The second pulse may be based on the pulse characteristics set or determined in operation  404  and/or the characteristics of the first pulse. For example, the second pulse may have a polarity that is opposite the polarity of the first pulse. Thus, the polarity of the second pulse may be based on the polarity of the first pulse. The duration of the second pulse may also be based on the duration of the first pulse. For instance, the second pulse may have the same or substantially the same duration as the first pulse. Accordingly, in examples, the second pulse causes the ball of the valve to rotate by the same amount, but in the opposite direction, as the ball rotated due to the first pulse. In some examples, the duration of the second pulse is longer than the duration of the first pulse. Having the duration of the second pulse be greater than the duration of the first pulse may help ensure that the valve returns to either the fully open or fully closed position. For instance, if the valve starts in the fully opened position and the first pulse causes the ball of the valve to rotate slightly towards the fully closed position, a longer duration for the second pulse having the opposite polarity from the first pulse will cause the ball to rotate back to the fully open position (e.g., the 0-degree position). Over-rotation past the fully open position may not be a concern where limit switches are in place to prevent such over-rotation. 
     At operation  414 , the second pulse is provided to the actuator. The second pulse may be provided to the actuator in the same manner as the first pulse. At operation  416 , the actuator receives the second pulse and rotates the ball of the ball valve based on the second pulse. For example, the actuator rotates the ball of the valve based on the duration of the second pulse, and the direction of the rotation is based on the polarity of the second pulse. 
     While not depicted, method  400  may continue to generate additional pulses, such as a third pulse and a fourth pulse. The third pulse may be substantially the same as the first pulse, and the fourth pulse may be substantially the same as the second pulse. 
       FIG.  5    depicts an example method  500  for controlling multiple ball valves. Operations of method  500  may be performed by any of the components descried herein or a combination of such components. For instance, some operations may be performed by a utility control device remotely located from the ball valve. 
     At operation  502 , a first series of pulses may be generated. The series of pulses may include the first pulse and the second pulse generated in method  400 . The first series of pulses may be based on prior pulses, a currently detected position of one or more valves in a first set of valves, or input received via input components, among other possible factors. For instance, a subset of valves that are under the control of the utility control device may share some common attributes that make that subset of valves suitable for resistance-reduction by the same series of pulses. As an example, a subset of valves may all be in the in the fully open or fully closed state or position. As another example, a subset of valves may all control gas or liquid. Accordingly, while not depicted, method  500  may also include determining the position of a plurality of valves and identifying subsets of valves sharing the same position. 
     The first series of pulses generated in operation  502  may include multiple pulse pairs, such as a first pulse pair and a second pulse pair. The first pulse pair includes a first pulse and a second pulse, and the second pulse pair includes a third pulse and a fourth pulse. The second pulse occurs a time interval (T) after the first pulse, and the fourth pulse may occur the time interval (T) after the third pulse. The third pulse occurs a period (P) after the first pulse. In some examples, the ratio between the time interval (T) and the period (P) is less than 1/100. The period (P) may be at least an hour. The first pulse may have a first polarity based on the position of the valve, and the second pulse may have a polarity opposite the polarity of the first valve. Similarly, the third pulse may have a polarity that is the same as the first pulse, and the fourth pulse may have a polarity that is the same as the second pulse. In other examples, during the period (P) the valve may move from a fully open position to a fully closed position, or vice-versa. In such an example, the third pulse may be based on the position of the valve, and therefore have a polarity opposite the polarity of the first pulse. 
     At operation  504 , a second series of pulses is generated. The second series of pulses may be for a second set of valves, which may be a subset of valves that are controlled by the utility control device. The second series of pulses may be similar to the first series of pulses, but the characteristics of the second series of pulses may be different from the characteristics of the second series of pulses. For example, the duration, amplitude, and/or polarity of the pulses in the second series of pulses may differ from the pulses in the first series. The period (P) and/or the time interval (T) for the second series of pulses may differ from that of the first series of pulses. The characteristics of the second series of pulses may be based on prior pulses, a currently detected position of one or more valves in a second set of valves, or input received via input components, among other possible factors. 
     At operation  506 , the first series of pulses is transmitted to the first set of valves. The first series of pulses may be transmitted via a wired or wireless connection. At operation  508 , the second series of pulses is transmitted to the second set of valves. In examples, the first series of pulses may be different from the second series of pulses; for example, this may be the case where the purpose of the first set of valves (e.g., gas) is different from the second set of valves (e.g., water). In some examples, the first set of valves includes a single valve and the second set of valves includes a single valve. At operation  510 , the actuators of the first set of valves rotate the balls of the valves according to or based on the first series of pulses. At operation  512 , the actuators of the second set of valves rotate the balls of the valves according to or based on the second series of pulses. 
       FIG.  6    depicts an example method  600  for calibrating a control system for a ball valve. Different types of ball valves and actuators may require different types of pulses and may react differently when power is applied to the actuators. For instance, upon application of power or a signal, some actuators may have a delay before physical rotation of the ball actually occurs. In addition, the rotational speed at which the valve rotates may also vary between different valves and actuators. To account for these differences, the present technology may automatically calibrate to a connected actuator and ball valve to determine the proper pulse durations. One such example calibration method is depicted in  FIG.  6    as method  600 . In method  600 , the valve for which calibration is being performed is a valve that has a closed limit switch for the fully closed position, such as the 90-degree position, and an open limit switch for the fully open position, such as the 0-degree position. The method  600  begins with the valve in the fully closed position that may be indicated by a signal from the closed limit switch. 
     At operation  602 , a signal is applied to the actuator of the valve to open the valve. The signal may be a positive voltage or other type of signal that is configured to cause the particular actuator being calibrated to turn the valve towards the fully open position. As used herein, the signal may be referred to as an “open signal.” The start of the open signal occurs at time T 0 . 
     At operation  604 , while the open signal is still being applied, a signal from the closed limit switch is received indicating that the ball valve has moved from the position in contact with the limit switch (e.g., the 90-degree position). The received signal indicates that the valve has begun rotating towards the fully open position. The received signal from the closed limit switch occurs at time T 1 . At operation  606 , a delay time (T Delay ) between applying the open signal and receiving the signal from the closed limit switch is calculated. The delay time (T Delay ) may be equal to T 1 -T 0 . 
     At operation  608 , a signal is received from the open limit switch indicating that the valve has reached the fully open position and/or has reached the position of the open limit switch. The signal from the open limit switch is received at time T 3 . At operation  610 , a rotation time (T Rot ) is calculated. The rotation time (T Rot ) is the duration of time that occurred between the start of rotation from the fully closed position to the time the valve reached the fully open position. The rotation time (T Rot ) is equal to T 3 −T 2 . 
     At operation  612 , a rate of rotation (R Rot ) is determined. The rate of rotation (R Rot ) may be represented in time per degree of rotation. The rate of rotation (R Rot ) may be determined by dividing the rotation time (T Rot ) by the number of degrees (N Total ) that the ball of the valve rotated. In an example, the ball may rotate 90 degrees from the fully closed position to the fully open position. At operation  614 , a pulse duration (D) for a desired rotation angle or desired number of degrees of rotation (N Desired ) is determined. The pulse duration (D) may be determined based on the determined rate of rotation (R Rot ) and the determined delay time (T Delay ) for the particular valve for which the calibration is being performed. For instance, the pulse duration (D) for a desired number of degrees of rotation (N Desired ) may be determined by the following equation:
 
 D=N   Desired   R   Rot   +T   Delay  
 
As an example, an example valve may take a total rotation time (T Rot ) of 5 seconds to rotate 90 degrees (N Total ) and may have a delay time (T Delay ) of 50 milliseconds (ms). In such an example, the rate of rotation (R Rot ) is about 55 ms per degree. Accordingly, to rotate the valve by 2 degrees, a pulse duration (D) of about 160 ms may be used.
 
The method  600  may be performed when a control system or device is initially connected to the actuator of a ball valve. The method  600  may also be periodically repeated to check that calculated rates of rotation and delay times have not changed for the valve. As should be appreciated, the principles of method  600  may also be applied for the valve rotating in the opposite direction. For instance, the valve may begin in a fully open state and the time to rotate the valve to the fully closed position may be calculated. Similar delay times and rotation rates may then be calculated for rotating the valve in a direction from open to closed.
 
     It should be appreciated that while the present discussion provided herein primarily uses a two-way ball valve for purposes of providing examples, it should be appreciated that the technology provided herein may be applied to a multi-way ball valve (e.g., a three-way ball valve) to help prevent such a valve from sticking. The present technology may also be applicable to other valves that are susceptible to sticking. 
     In addition, some aspects of the present disclosure are described above with reference to block diagrams and/or operational illustrations of systems and methods according to aspects of this disclosure. The functions, operations, and/or acts noted in the blocks may occur out of the order that is shown in any respective flowchart. For example, two blocks shown in succession may in fact be executed or performed substantially concurrently or in reverse order, depending on the functionality and implementation involved. 
     Numerous other changes may be made which will readily suggest themselves to those skilled in the art and which are encompassed in the spirit of the disclosure and as defined in the appended claims. While various aspects have been described for purposes of this disclosure, various changes and modifications may be made which are well within the scope of the present invention. Numerous other changes may be made which will readily suggest themselves to those skilled in the art and which are encompassed in the spirit of the disclosure and as defined in the claims. 
     Further, as used herein and in the claims, the phrase “at least one of element A, element B, or element C” is intended to convey any of: element A, element B, element C, elements A and B, elements A and C, elements B and C, and elements A, B, and C. In addition, one having skill in the art will understand the degree to which terms such as “about” or “substantially” convey in light of the measurements techniques utilized herein. To the extent such terms may not be clearly defined or understood by one having skill in the art, the term “about” shall mean plus or minus ten percent.