Low bleed fluid control system

Abstract

A fluid control system is provided for controlling flow of process fluid through a conduit. The fluid control system may include a valve arranged to control a flow of a process fluid; an actuator configured to adjust a position of the valve; and a controller configured to control movement of the actuator. The system may include a switching valve in communication with the actuator and the controller. Further, the solenoid valve may be in communication with the first port of the switching valve. In one example, according to a pressure at a first port of the switching valve, the switching valve may be operated in a first state to provide process fluid to a valve controller and permit movement of the actuator, and in a second state to prevent flow of process fluid to the valve controller and flow of process fluid from the pneumatic actuator.

Description

Technical Field

[0001] The present invention relates to a fluid control system and a method for controlling the flow of fluid through a valve on a pipeline. Background Art

[0002] Fluid control systems can be used in a variety of industrial, commercial, and other applications to regulate, protect, isolate, or maintain the flow of fluids within pipes, conduits, or other containers and therein (e.g., within pipelines). However, typical control systems often vent a portion of the controlled fluid (e.g., pipeline gas), which can result in the loss of valuable materials (e.g., natural gas) and may have regulatory consequences. Summary of the invention

[0003] Some embodiments of the present invention provide a fluid control system for controlling the flow of a process fluid through a pipeline. The fluid control system may include: a valve arranged to control the flow of a process fluid, an actuator configured to adjust the position of the valve, and a controller configured to control the movement of the actuator. The system may include a switching valve that communicates with both the actuator and the controller. In addition, a solenoid valve may be connected to a first port of the switching valve. In one example, the switching valve may operate in a first state to provide a process fluid to a valve controller and allow the actuator to move, depending on the pressure at the first port of the switching valve, and the switching valve may also operate in a second state to prevent the process fluid from flowing to the valve controller and prevent the process fluid from flowing from a pneumatic actuator. In another example, the solenoid valve can be controlled to enable or disable the pressurization of the first port of the switching valve by the process flow to control the operation of the valve controller for moving the pneumatic actuator.

[0004] Some embodiments of the present invention provide a fluid control system for controlling the flow of a process fluid through a pipeline. The fluid control system may include a valve controller and a fluid switching device, wherein the valve controller is configured to control a pneumatic actuator to adjust the position of a valve of the pipeline using a process fluid from a process stream flowing through the pipeline, and the fluid switching device is arranged along a flow path between the valve controller and an upstream portion of the pipeline. In one example, the fluid switching device is configured to selectively enable or disable the flow of the process fluid from the upstream portion of the pipeline to the valve controller based on the pressure in the downstream portion of the pipeline to: supply the process fluid to the valve controller to adjust the position of the valve, and provide a zero-bleed steady state for the valve controller.

[0005] Some embodiments of the present invention provide a method of controlling fluid flow through a valve on a pipeline. The method may include: monitoring pressure in a downstream portion of the pipeline and operating a switching device to selectively enable process fluid to flow from an upstream portion of the pipeline to a valve controller based on the pressure in the downstream portion of the pipeline, and operating the valve controller using the flow of the process fluid through the switching device to adjust the position of the valve. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] The accompanying drawings, which are incorporated in and form a part of this specification, illustrate embodiments of the present invention and, together with the description, serve to explain the principles of the embodiments of the present invention:

[0007] Figure 1 is a schematic diagram of an example of a circuit including a fluid control system according to aspects of the present disclosure.

[0008] Figure 2 is another configuration of a fluid control system including aspects of the present disclosure Figure 1 Schematic diagram of the pipeline.

[0009] Figure 3 A fluid control system according to an aspect of the present disclosure includes yet another configuration Figure 1 Schematic diagram of the pipeline. DETAILED DESCRIPTION

[0010] The following discussion is presented to enable those skilled in the art to make and use embodiments of the present invention. Various modifications to the illustrated embodiments will be apparent to those skilled in the art in view of the benefit of this disclosure, and the principles herein may be applied to other embodiments and applications without departing from embodiments of the present invention. Therefore, embodiments of the present invention are not intended to be limited to the embodiments illustrated, but should be accorded the widest scope consistent with the principles and features disclosed herein.

[0011] The following detailed description will be read with reference to the accompanying drawings, in which similar elements in different drawings have similar reference numerals. The accompanying drawings are not necessarily drawn to scale, and the accompanying drawings depict selected embodiments and are not intended to limit the scope of embodiments of the invention. The skilled person will recognize that the examples provided herein have many useful alternatives and fall within the scope of embodiments of the invention.

[0012] Before explaining any embodiment of the present invention in detail, it should be understood that the application of the present invention is not limited to the details of the construction and arrangement of the components set forth in the following description or shown in the following drawings. The present invention can have other embodiments and can be practiced or executed in various ways. In addition, it should be understood that the words and terms used herein are for descriptive purposes and should not be considered as limiting. "Including," "including," or "having" and their variants used herein are intended to cover the items listed thereafter and their equivalents and additional items. Unless otherwise specified or limited, the terms "install," "connect," "support," and "couple" and their variants are widely used and cover direct and indirect installations, connections, supports, and connections. In addition, "connect" and "couple" are not limited to physical or mechanical connections or connections.

[0013] As briefly discussed above, fluid control systems can be used in a variety of industrial, commercial, and other situations to control the flow of fluids through pipes, conduits, or other containers. However, some fluid control systems operate in a state of continuous release or discharge, which results in the loss of valuable process fluids to the atmosphere. The loss of process fluids to the atmosphere may result in unnecessary loss of profits or product. In addition, excessive discharge of process fluids may trigger certain regulatory consequences.

[0014] Embodiments of the present invention may provide a zero-discharge fluid control system. The fluid control system allows process fluid to flow to one or more instruments (e.g., a controller, a positioner, etc.) only when it is necessary to operate the valve via one or more instruments. Generally speaking, the switching device may be configured to controllably provide the flow of process fluid to the valve controller to drive the control valve only when the control system determines that the valve controller needs to be operated (e.g., when the downstream line pressure differs sufficiently from the set point pressure). Thus, for example, a pneumatic actuator may be selectively operated by a valve controller using process fluid from a process flow to control a valve. In addition, when the actuator does not need to be operated, the process fluid may be prevented from flowing to the valve controller so that the discharge from the valve controller is zero in a stable state (i.e., when the actuator is not moving).

[0015] In some examples, the system may include a remote control device (e.g., a remote computer of one or more known configurations) configured to control the flow of a process fluid to one or more instruments via a switching device. For example, the remote device can energize / de-energize (e.g., open / close) the solenoid valve to selectively change the state of the switching valve via the process fluid flowing to (or not flowing to) the switching valve. In one example, flow to the switching valve is enabled by opening the solenoid valve, which places the switching valve in an open state and thereby allows the process fluid to flow to one or more instruments to adjust the position of the valve. In another example, flow to the switching valve is prohibited by closing the solenoid valve, which places the switching valve in a closed state, thereby preventing the process fluid from flowing to one or more instruments. Therefore, when the switching valve is closed (i.e., the solenoid coil is closed), the fluid control system does not discharge / release any process fluid to the atmosphere.

[0016] In some examples, the switching valve may include various known types of trip valves, wherein the open (or first) state corresponds to the reset state of the trip valve, and the closed (or second) state corresponds to the trip state of the trip valve. In other examples, other known types of switching valves with similar functions may be used. For example, any leak-free (e.g., soft seat) valve including a single input device and two or more output devices may be used, and the output devices are configured to operate in coordination (e.g., all output devices are open and / or all output devices are closed). In addition, in some cases, the switching device may include a solenoid valve as the switching valve (e.g., a six-way two-position solenoid valve).

[0017] In one example, the remote device can monitor a pressure sensor positioned on the downstream portion of the pipeline to determine the process error between the desired pressure in the downstream portion of the pipeline and the actual pressure in the downstream portion of the pipeline. When the process error is within a predetermined range, the remote device can prevent the process fluid from flowing to one or more instruments (e.g., the solenoid coil can be closed to move the switching valve to a closed state) because the valve is in a stable state. However, when the process error exceeds the predetermined range, the remote device opens to allow the process fluid to flow to one or more instruments (e.g., the solenoid coil can be opened to move the switching valve to an open state) to adjust the position of the valve. Once the process error is within the predetermined range, the remote device can again prevent the process fluid from flowing to one or more instruments (e.g., the solenoid coil can be closed again to move the switching valve to a closed state) to prevent unnecessary discharge of the process fluid.

[0018] Figure 1 An example of a fluid control system 100 arranged on a pipeline 105 is shown. In one example, the pipeline 105 can be a natural gas pipeline. In one example, the pipeline 105 can include a valve 110 located in a tube of the pipeline 105. The valve 110 can control the fluid flow, pressure, or other factors between an upstream portion 115 (relative to the valve 110) and a downstream portion 120 (relative to the valve 110) of the pipeline 105. The valve 110 can be any of a variety of known types. For example, the valve 110 can be a ball valve, a gate valve, a butterfly valve, a diaphragm valve, a stop valve, a plug valve, a check valve, or any other form of valve for changing pipeline pressure or flow. In a specific example, the valve can be a push-down closing valve with a fail-open actuation.

[0019] In the example shown, the valve 110 is in fluid communication with a process fluid (e.g., natural gas, oil, water, or other fluid) flowing through the pipeline 105. The valve 110 can be stroked (i.e., moved / actuated) via a pneumatic actuator 130 to close, open, or otherwise adjust the position of the valve stem 125 of the valve 110 to produce a predetermined fluid pressure or flow in the downstream portion 120 of the pipeline 105. In one example, the actuator 130 can be a double-acting piston-type actuator. In another example, the actuator can be a single-acting piston-type actuator, or can have other known configurations. In some examples, the actuator can include a biasing element 190 (e.g., a spring) configured to cause the actuator to "fail-open". In other examples, the biasing element can be positioned or configured to cause the actuator to "fail-close". Therefore, the biasing element 190 can operate the actuator in certain circumstances. For example, a situation where the pressure difference (dP) is insufficient to operate the actuator 130.

[0020] In one example, the fluid control system 100 includes a controller 135 configured to control the actuator 130. For example, the controller can be in the form of various known types of digital valve controllers (DVC). The controller 135 can control the position of the actuator 130 based on one or more signals from the remote device 140. The remote device 140 can be in the form of a remote computer, a remote server, a microprocessor, an electronic controller, a mobile device, or any other remote device (e.g., various known digital control devices). In a specific example, the controller 135 can receive a 4mA to 20mA signal corresponding to a predetermined valve stroke (e.g., 0% to 100%) from the remote device 140. In other examples, the 4mA to 20mA signal from the remote device 140 can correspond to a predetermined pressure value (e.g., 3psi to 15psi). The remote device 140 can communicate with the controller 135 via a wired or wireless connection. In some examples, the remote device 140 can receive power (e.g., electrical energy) from a generator, one or more solar panels, one or more power distribution lines, or any other power source.

[0021] The remote device 140 may also communicate with a pressure sensor 145 configured to monitor the pressure in the downstream portion 120 of the pipeline 105. In one example, the remote device 140 may monitor the pressure sensor 145 to determine whether the position of the valve 110 needs to be adjusted via the actuator 130. If the actuator 130 needs to be adjusted, the remote device 140 may send a signal to the controller 135 to effectuate the adjustment of the actuator 130. The remote device 140 may also communicate with a flow meter 155 disposed on an input line 160 of the fluid control system 100. The flow meter 155 may be configured to measure the flow rate of the process fluid siphoned away from the upstream portion 115 of the pipeline 105 via the input line 160. In one example, the remote device 140 may record or log the data received from the flow meter 155 for use in meeting certain regulatory reporting requirements.

[0022] As previously described, input line 160 is configured to siphon process fluid from upstream portion 115 of pipeline 105 for actuating actuator 130 via controller 135. In one example, the process fluid siphoned from upstream portion 115 of pipeline 105 via input line 160 may pass through regulator 165, which is configured to reduce the pressure of the process fluid in input line 160 to a predetermined value. In some examples, regulator 165 may be positioned upstream of flow meter 155 on input line 160.

[0023] To control the flow of process fluid to the controller 135, the switching device 148 can be fluidly disposed between the upstream portion 115 of the pipeline and the actuator 130 and the controller 135 (i.e., upstream of both the actuator 130 and the controller 135 as shown) and downstream of the upstream portion 115 along the input line 160. In general, the switching device 148 can include a variety of known types of valves to selectively control the flow from the upstream portion 115 of the pipeline to the actuator 130 and the associated control device (e.g., the controller 135, as shown), and in particular to selectively enable or prevent the flow from the pipeline 105 to the control device. In some examples, as described above, the switching device 148 can include one or more solenoid valves, including for controlling the flow to a switching valve (e.g., a trip valve as specifically shown and further described below), or for directly controlling the flow to a valve controller (e.g., using a 6-way 2-position solenoid valve, which may not require a corresponding trip valve).

[0024] like Figure 1In the example shown, in particular, the switching valve 170 can be positioned on the input line 160 downstream of both the regulator 165 and the flow meter 155. The switching valve 170 can be configured to enable the process fluid to flow to the controller 135 and the process fluid to flow from the controller 135 to the actuator 130 based on the supply of process fluid to the port 170A of the switching valve 170. In other words, when the process fluid with sufficient pressure is received from the input line 160 at the port 170A, the switching valve 170 can be in a first state to enable the process fluid to flow to the controller 135 and the process fluid to flow from the controller 135 to the actuator 130. However, when the switching valve 170 does not receive the process fluid with sufficient pressure at the port 170A (via the input line 160), the switching valve 170 switches to a second state to prevent the process fluid from flowing to the controller 135 and from the controller 135 and the actuator 130. Thus, when the switching valve 170 prevents flow to or from the controller 135 and the actuator 130, the fluid control system 100 does not bleed (i.e., exhaust) any process fluid to the atmosphere. However, when the switching valve 170 enables flow to or from the controller 135, the controller 135 can operate to power the actuator 130, but the fluid control system 100 can also bleed the process fluid to the atmosphere. Therefore, the configuration of the fluid control system 100 is referred to as a zero-bleed configuration, in which the fluid control system 100 is configured to bleed or exhaust the process fluid to the atmosphere only when the actuator 130 actuates the valve 110. In other words, when the valve 110 does not need to move (e.g., in a stable state), the fluid control system 100 does not bleed or exhaust the process fluid.

[0025] In the example shown, the switching valve 170 is a trip valve of known configuration that can be "tripped" to prevent flow when the pressure at port 170A drops below a set point, and can be "reset" to allow flow when the pressure at port 170A is equal to or above the set point. However, in other examples, other types of switching valves having similar functions may be used.

[0026] As described above, the switching valve 170 is configured to trip or reset based on whether the switching valve 170 receives process fluid at the port 170A via the input line 160. To control the flow of process fluid into the port 170A, the solenoid valve 150 is positioned upstream of the switching valve 170 and downstream of both the regulator 165 and the flow meter 155. The solenoid valve 150 can be controlled (e.g., energized / de-energized, opened / closed) via the remote device 140 (or in other ways, including as further described below).

[0027] In one example, the remote device 140 opens / closes the solenoid valve 150 based on the error value between the currently measured pressure / flow in the downstream portion 120 and the required pressure / flow in the downstream portion 120. Therefore, as described above, the remote device 140 can selectively open / close the solenoid valve 150 to reduce the overall emission (e.g., the discharge / discharge of the process fluid). For example, when the valve 110 needs to be actuated so that the error value is within a predetermined range, the remote device 140 can only open the solenoid valve 150, thereby enabling the process fluid to flow to / or from the controller 135 via the switching valve 170. In another example, when the error value between the currently measured pressure / flow in the downstream portion 120 and the required pressure / flow in the downstream portion 120 is below a predetermined range, the remote device 140 can close the solenoid valve 150. Therefore, the total amount of process fluid discharged / discharged to the atmosphere is reduced (e.g., reduced to zero during the steady state of the actuator 130 and the controller 135).

[0028] In one example, the solenoid valve 150 can be configured to fail open (e.g., fail open when power is off) to enable process fluid to flow to port 170A of the switching valve 170 and thereby enable the fluid control system 100 to operate during a power outage. However, in other examples, the solenoid valve 150 can be configured to fail closed (e.g., fail closed when power is off) to prevent process fluid from flowing to port 170A and thereby prevent excessive bleed / drainage of process fluid during a power outage.

[0029] To facilitate control of the actuator 130 via the controller 135, the controller 135 includes a supply line 175 and an output line 180. In one example, the supply line 175 may include one or more segments or portions having a variable pressure depending on the state of the switching valve 170. For example, a first supply line segment 176 between the input line 160 and the switching valve 170 may be at a constant pressure that is equal to (e.g., regardless of the state of the switching valve 170) the pressure within the input line 160 regulated via the regulator 165. When the switching valve 170 is opened, the pressure of the second supply line segment 177 between the switching valve 170 and the supply pressure regulator 185 may be equal to the pressure in the first supply line segment 176. However, when the switching valve 170 is closed, the pressure of the second supply line segment 177 may be different from, or even lower than, the pressure of the first supply line segment 176 (for example, when the switching valve 170 is closed, the second supply line segment 177 discharges the gas to the atmosphere through the pneumatic instrument, and the pressure in the second supply line segment 177 becomes zero (0)). When the switching valve 170 is open, the third supply line segment 178 between the supply pressure regulator 185 and the instrument may be at the pressure set by the supply pressure regulator 185. However, when the switching valve 170 is closed, the pressure of the third supply line segment 178 may be different from, or even lower than the pressure of the first pipeline segment 176 (for example, when the switching valve 170 is closed, the third supply line segment 178 discharges the gas to the atmosphere through the pneumatic instrument, and the pressure in the third supply line segment 178 becomes zero (0)).

[0030] Correspondingly, the output line 180 may include one or more segments or portions having a variable pressure depending on the state of the switching valve 170. For example, when the switching valve 170 is open, the first output line segment 181 between the instrument and the switching valve 170 may be at a pressure determined by the instrument (e.g., the controller 135). However, when the switching valve 170 is closed, the first output line segment 181 may be at a different or even lower pressure. For example, the first output line segment 181 bleeds gas through the instrument (e.g., the controller 135). Therefore, when the switching valve 170 is closed, the pressure in the first output line segment 181 becomes zero (0). When the switching valve 170 is open, the pressure of the second output line segment 182 between the switching valve 170 and the actuator 130 may be equal to the pressure in the first output line segment 181. However, when the switching valve 170 is closed, the pressure in the second output line segment 182 may remain constant (e.g., no bleed / leak) to lock or maintain the position of the valve 110 via the actuator. Thus, fluid control system 100 is able to maintain the position of valve 110 without excessive venting / draining of the process fluid.

[0031] In one example, supply line 175 is configured to supply process fluid to controller 135, which is regulated or metered via controller 135 based on the amount of movement required by actuator 130. The metered process fluid flows from controller 135 via output line 180 into actuator 130, which adjusts the position of valve 110 via actuation of valve stem 125.

[0032] To prevent process fluid from flowing to or from the controller 135 when the valve 110 is in a stable state, the switching valve 170 is arranged along both the supply line 175 and the output line 180. Therefore, the process fluid cannot reach the controller 135 via the supply line 175 located downstream of the switching valve 170 when the switching valve 170 is closed (e.g., when the solenoid valve 150 is closed). Correspondingly, when the switching valve 170 is closed (e.g., when the solenoid valve 150 is closed), the metered process fluid cannot reach the actuator 130 via the output line 180 downstream of the switching valve 170. Alternatively, when the switching valve 170 is open (e.g., when the solenoid valve 150 is open), a portion of the process fluid can flow from the input line 160 via the supply line 175 and freely pass through the switching valve 170. Therefore, the switching valve 170 is configured to operate the first valve 171 located on the supply line 175 in cooperation with the second valve 172 located on the output line 180. In other words, the first valve 171 and the second valve 172 are actuated together between the open / closed valve positions. Therefore, when the first valve 171 is closed, the second valve 172 is closed, and vice versa. Correspondingly, when the first valve 171 is opened, the second valve 172 is opened.

[0033] In the illustrated example, the process fluid within the supply line 175 passes through a supply pressure regulator 185 disposed on the supply line 175. The supply pressure regulator 185 is configured to reduce the pressure of the process fluid to a predetermined value for use by the controller 135. The process fluid then flows into the controller 135, which meters the process fluid based on a signal from the remote device 140. The metered process fluid then flows through the output line 180 and freely passes through the switching valve 170 into the actuator 130. As previously described, the metered process fluid can therefore be used to adjust the position of the valve 110 via the movement of the valve stem 125.

[0034] Figure 2 Another example of a fluid control system 200 is shown, which can be used with Figure 1105 (e.g., as an alternative configuration of fluid control system 100). As will be appreciated, fluid control system 200 shares many common components with the previously shown and described examples and operates in a similar manner. For the sake of brevity, these common features will not be described in detail below. Instead, the previous discussion of commonly named or numbered features also applies to the example configuration of fluid control system 200 unless otherwise noted.

[0035] exist Figure 2 In the fluid control system 200 of FIG. 1 , the controller 135 (e.g., DVC) is replaced by a pneumatic controller 210 and a pneumatic positioner 215, which are configured to control the position of the valve 110 via the actuator 130. In order to monitor the position of the actuator 130, the fluid control system 200 may also include a position sensor 205 positioned near the actuator 130. The position sensor 205 is configured to communicate with the remote device 140 via wired or wireless communication, so that the remote device 140 can monitor the position of the actuator 130.

[0036] As previously described, the pneumatic controller 210 and the positioner 215 are configured to control actuation of the valve 110 via the actuator 130. In one example, the controller 210 is configured to monitor the pressure in the downstream portion 120 of the pipeline 105 via the reference line 220. The controller 210 is also configured to provide an output pressure signal to the positioner 215 via the control line 230 based on the pressure in the downstream portion 120 of the pipeline 105. To generate the output pressure signal, the controller 210 receives the process fluid via the input line 225 (a branch of the supply line 175 described previously) and generates the output pressure signal based on the pressure in the downstream portion 120 determined via the reference line 220. In one example, the output pressure signal is transmitted to the positioner 215 via the control line 230 to control the output from the positioner 215 to the actuator 130 (e.g., for adjusting the valve 110 via the actuator 130).

[0037] The positioner 215 is configured to receive process fluid from the supply line 175 and regulate / adjust the process fluid based on the output received from the controller 210 via the control line 230 to provide a control signal along the output line 180. Therefore, the combination of the controller 210 and the positioner 215 can be used to adjust the position of the valve 110 based on the pressure in the downstream portion 120 of the pipeline 105. Unlike the controller 135 discussed previously, the controller 210 and the positioner 215 do not rely on electricity to operate. Therefore, the controller 210 and the positioner 215 can continue to control the position of the valve 110 regardless of whether there is electricity. However, as previously described, when the remote device 140 closes the solenoid valve 150 and thereby trips the switching valve 170, the controller 210 and the positioner 215 may become inoperable (i.e., the valve 110 becomes inoperable). Thus, when the process error is within a predetermined threshold, the remote device 140 may close the solenoid valve 150 and trip the switching valve 170 to prevent unnecessary venting / releasing of the process fluid via the controller 210 and the positioner 215. When the process error exceeds the predetermined threshold, the remote device 140 may open the solenoid valve 150 and reset the switching valve 170 to enable movement of the valve 110 via the controller 210 and the positioner 215. As previously described, this configuration is referred to as a zero-bleed configuration, which may reduce the amount of process fluid vented / releasing to the atmosphere.

[0038] In some examples, the controller 210 can be replaced by a low-drain pilot device of various known configurations. In other examples, both the controller 210 and the positioner 215 can be replaced by a low-drain pilot device based on user preference.

[0039] Figure 3 Another example of a fluid control system 300 is shown, which can be used with Figure 1 105 (e.g., as an alternative configuration of fluid control system 100). As will be appreciated, fluid control system 300 shares many common components with the previously shown and described examples and operates in a similar manner. For the sake of brevity, these common features will not be described in detail below. Instead, the previous discussion of commonly named or numbered features also applies to the example configuration of fluid control system 300 unless otherwise noted.

[0040] In the event that the remote device 140 is not available (or not required), the controller 305 (e.g., a digital process controller (DPC)) can be configured to control actuation of the valve 110 via the actuator 130. In lieu of the remote device 140, the controller 305 is configured to communicate with the pressure sensor 145 to monitor the pressure / flow in the downstream portion 120 of the pipeline 105. Based on the pressure / flow in the downstream portion 120, the controller 305 is configured to regulate / adjust the pressure or flow of the process fluid received via the supply line 175 to be output via the output line 180. As previously described, the regulated process fluid output from the controller 305 via the output line 180 can then be used to adjust the position of the valve 110 via the actuator 130. In one example, the controller 305 is also configured to control the operation of the solenoid valve 150 (e.g., energize / de-energize the solenoid valve 150) based on the sensed pressure in the downstream portion 120 of the pipeline 105 or another control value. For example, the controller 305 is configured to energize / de-energize a low power solenoid valve (eg, less than 1 Watt).

[0041] As previously described, when the controller 305 closes the solenoid valve 150 and thereby trips the switching valve 170, the controller 305 may be unable to pneumatically actuate the valve 110 (i.e., the valve 110 remains in a stable state). Therefore, when the process error is within a predetermined threshold, the controller 305 may close the solenoid valve 150 and trip the switching valve 170 to prevent unnecessary venting / bleeding of the process fluid via the controller 305. When the process error exceeds the predetermined threshold, the controller 305 may open the solenoid valve 150 and reset the switching valve 170 to enable movement of the valve 110 via the controller 305. As previously described, this configuration is referred to as a zero bleed configuration, which may reduce the amount of process fluid vented / bleeded to the atmosphere.

[0042] In the absence of remote device 140, fluid control system 300 may include totalizer 310 in communication with flow meter 155. Totalizer 310 may be configured to monitor flow meter 155 to produce a value for the total process fluid consumed or exhausted by fluid control system 300. Thus, certain regulatory reporting requirements may be met.

[0043] In some embodiments, the devices or systems disclosed herein may be utilized, manufactured, or installed using methods that embody various aspects of the present invention. Accordingly, any description herein of a particular feature, capability, or intended purpose of a device or system is generally intended to include disclosure of methods of using such a device for its intended purpose, methods of otherwise achieving such capabilities, methods of manufacturing related components of such a device or system (or the entire device or system), and methods of installing disclosed (or otherwise known) components to support such purposes or capabilities. Similarly, unless otherwise specified or limited, any discussion herein of any method of manufacturing or using a particular device or system (including installing the device or system) is intended to inherently include disclosure of the use features and achieved capabilities of such a device or system as an embodiment of the present invention.

[0044] In addition, unless otherwise limited or defined, "or" as used herein represents a non-exclusive list of components or operations that can exist in any combination, rather than an exclusive list of components that can only exist as alternatives to each other. For example, a list of "A, B, or C" represents the following options: A; B; C; A and B; A and C; B and C and A, B, C. Correspondingly, the term "or" as used herein is used to represent exclusive alternatives only when preceded by an exclusive term, such as "any one," "one of," "only one of," or "exactly one of." For example, a list of "one of A, B, or C" represents the following options: A, but not B and C; B, but not A and C; C, but not A and B. A list of "one or more" (and variations thereof) preceded by "or" to separate the listed elements represents one or more options in any or all of the listed elements. For example, the phrases "one or more of A, B, or C" and "at least one of A, B, or C" represent the following options: one or more A; one or more B; one or more C; one or more A and one or more B; one or more B and one or more C; one or more A and one or more C; and one or more of A, one or more of B, and one or more of C. Similarly, a list beginning with "plurality" (and variations thereof) and including "or" to separate the listed elements represents the option of multiple instances of any one or all of the listed elements. For example, the phrases "plurality of A, B, or C" and "two or more of A, B, or C" represent the following options: A and B; B and C; A and C; and A, B, and C.

[0045] As used herein, unless otherwise defined or limited, directional terms are used to facilitate reference to a particular figure or example for discussion. For example, references to a downward (or other) direction or a top (or other) position may be used to discuss various aspects of a particular example or figure, but do not necessarily require similar orientation or geometry in all installations or configurations.

[0046] In addition, unless otherwise limited or defined, "substantially parallel" as used herein means that the angle with the reference direction is within ±12 degrees (e.g., within ±6 degrees), including this number. For a nonlinear path, if the straight line between the end points of the path is substantially parallel to the reference direction or the path is substantially parallel to the reference direction as the average derivative of the reference direction in a common reference system, then the path can be considered to be substantially parallel to the reference direction.

[0047] Also as used herein, unless otherwise limited or defined, "substantially perpendicular" means a direction that is perpendicular to a reference direction within ±12 degrees (e.g., within ±6 degrees) (including this number). For a nonlinear path, a path may be considered substantially perpendicular to a reference direction if a straight line between the endpoints of the path is substantially perpendicular to the reference direction or if the path is substantially perpendicular to the reference direction as an average derivative of the reference direction in a common reference frame.

[0048] Also as used herein, unless otherwise limited or defined, "integral" and its derivatives (e.g., "integrally") describe an element that is manufactured as a single piece, without fasteners, adhesives, or the like to secure the separate components together. For example, an element that is stamped, cast, or otherwise molded from a single piece of metal sheet as a single component or using a single mold, without the use of rivets, screws, or adhesives to hold the separately formed parts together, is an integral (and one-piece) element. In contrast, an element that is composed of multiple parts that are initially formed separately and then joined together is not an integral (or one-piece) element.

[0049] In addition, unless otherwise specified or limited, the terms "about" and "approximately" in connection with reference values ​​herein refer to changes of ±15% or less compared to the reference value, including the endpoints of the range. Similarly, the term "substantially equal" (and similar terms) used herein with respect to a reference value refers to a change of less than ±30% (including 30%) from the reference value. When specifically stated, "substantially" may particularly refer to a change in a numerical direction relative to the reference value. For example, "substantially less than" a reference value (and similar values) means a value that is reduced by 30% or more compared to the reference value, while "substantially greater than" a reference value (and similar values) means a value that is increased by 30% or more compared to the reference value.

[0050] Also as used herein, unless otherwise limited or specified, "substantially the same" refers to two or more components or systems that are manufactured or used according to the same process and specifications, where the differences between the components or systems are within the acceptable tolerances for the relevant processes and specifications. For example, if the components are manufactured according to the same standardized manufacturing steps, with the same materials, and within the same acceptable dimensional tolerances (e.g., specified for a particular process or product), then the two components can be considered substantially the same.

[0051] The previous description of the disclosed embodiments is provided to enable those skilled in the art to make or use the invention. Various modifications to these embodiments will be apparent to those skilled in the art in view of the benefit of this disclosure, and the principles defined herein may be applied to other embodiments without departing from the spirit and scope of the invention. Therefore, the objects of the present invention are not limited to the embodiments shown herein, but are given the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A fluid control system, comprising: a valve arranged to control a process flow of a process fluid; a pneumatic actuator configured to adjust a position of the valve; a valve controller configured to control movement of the pneumatic actuator; a switching valve in fluid communication with the pneumatic actuator and the valve controller; and a solenoid valve, the solenoid valve being in fluid communication with the first port of the switching valve; Characterized in that, according to the pressure at the first port of the switching valve, the switching valve can operate in the following states: in a first state, the flow of the process fluid is provided to the valve controller and the movement of the pneumatic actuator is allowed; and in a second state, the process fluid is prevented from flowing to the valve controller and the process fluid is prevented from flowing from the pneumatic actuator; and Wherein, the solenoid valve is controllable to enable or disable pressurization of the first port of the switching valve by the process fluid to control operation of the valve controller for movement of the pneumatic actuator.

2. The fluid control system according to claim 1, characterized in that: The valve controller is powered by process fluid from a process flow upstream of the valve via the switching valve.

3. The fluid control system according to claim 2, characterized in that: The solenoid valve is configured to controllably block the flow of the process fluid to the first port of the switching valve to place the switching valve in the second state and thereby provide zero steady-state relief from the fluid control system.

4. The fluid control system according to claim 1, characterized in that: The switching valve is a trip valve, the first state is a reset state, and the second state is a trip state.

5. The fluid control system according to claim 4, characterized in that: the solenoid valve being configured to be de-energized to reset the trip valve to provide flow of process fluid to the valve controller via the trip valve; and Wherein, the solenoid valve is configured to be energized to trip the trip valve to prevent the process fluid from flowing to the valve controller.

6. The fluid control system according to claim 1, characterized in that: The fluid control system further comprises: A remote digital controller is configured to control the solenoid valve to enable or disable pressurization of the first port of the switching valve.

7. The fluid control system according to claim 6, characterized in that: The remote digital controller is configured to control the solenoid valve based on signals from one or more of the following devices: a pressure sensor arranged downstream of the valve; a flow meter arranged upstream of the solenoid valve; or a position sensor, the position sensor being arranged to monitor movement of the pneumatic actuator.

8. The fluid control system according to claim 1, characterized in that: The valve controller is in fluid communication with the switching valve and in electronic communication with the solenoid valve and is configured to: electronically control the solenoid valve based on a pressure of a process flow downstream of the valve; and provide pneumatic power to the pneumatic actuator using process fluid received via the switching valve.

9. The fluid control system according to claim 1, characterized in that: The valve controller is a pneumatic pressure controller in fluid communication with the switching valve; and Wherein, the fluid control system further comprises: a pneumatic positioner in fluid communication with both the pneumatic pressure controller and the switching valve; Wherein, the pneumatic positioner is configured to adjust the position of the pneumatic actuator based on a fluid signal from the pneumatic pressure controller.

10. A fluid control system, comprising: a valve controller configured to control the pneumatic actuator to adjust a position of a valve in the pipeline using process fluid from a process flow through the pipeline; a fluid switching device disposed along a flow path between the valve controller and an upstream portion of the pipeline; It is characterized in that the fluid switching device is configured to selectively enable or disable the flow of process fluid from the upstream portion of the pipeline to the valve controller based on the pressure in the downstream portion of the pipeline, so as to: supply process fluid to the valve controller to adjust the position of the valve; and provide a zero-discharge steady state for the valve controller.

11. The fluid control system according to claim 10, characterized in that: The fluid switching device includes a six-way two-position solenoid valve.

12. The fluid control system according to claim 10, characterized in that: The fluid switching device includes a trip valve located upstream of the valve controller and in fluid communication with the valve controller, the trip valve being in communication with the upstream portion of the pipeline via a solenoid valve; and Wherein one or more of the valve controller or the remote control device is configured to operate the solenoid valve to selectively trip or reset the trip valve based on the pressure in the downstream portion of the pipeline.

13. The fluid control system according to claim 12, characterized in that: One or more of the valve controller or the remote control device is configured to operate the solenoid valve based on the pressure in the downstream of the pipeline to selectively: pressurizing a first port of the trip valve to reset the trip valve and allow the process fluid to flow from the upstream portion of the pipeline to the valve controller; as well as The first port of the trip valve is blocked to trip the trip valve and prevent the process fluid from flowing from the upstream portion of the pipeline to the valve controller.

14. The fluid control system according to claim 13, characterized in that: One or more of the valve controller or the remote control device is configured to provide power to the solenoid valve to block the first port of the trip valve.

15. The fluid control system according to claim 14, characterized in that: One or more of the valve controller or remote control device is configured to de-energize the solenoid valve to pressurize the first port of the trip valve.

16. The fluid control system according to claim 10, characterized in that: The valve controller is a digital valve controller configured to be electronically controlled by a remote control device based on the pressure in the downstream portion of the pipeline.

17. The fluid control system according to claim 16, characterized in that: The remote control device is also configured to electronically control the fluid switching device based on the pressure in the downstream portion of the pipeline.

18. A method for controlling the flow of a fluid through a valve in a pipeline, the method comprising: monitoring the pressure in the downstream portion of the pipeline; and Based on the pressure in the downstream portion of the pipeline: operating a switching device to selectively allow process fluid to flow from an upstream portion of the pipeline to the valve controller; and A valve controller is operated to adjust the position of the valve using the flow of the process fluid through the switching device.

19. The method according to claim 18, characterized in that The switching device includes a switching valve and a solenoid valve; and Wherein, when the solenoid valve is closed, flow of process fluid through the switching valve is disabled to provide a zero bleed steady state at the valve controller.

20. The method according to claim 19, characterized in that When the solenoid valve is open, process fluid is enabled to flow through the switching valve.

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