Control system with dynamic reference pressure

Abstract

The invention relates to a control system with dynamic reference pressure. A fluid control system for controlling flow of process fluid through a conduit is provided. The fluid control system may include a valve, one or more instruments in fluid communication with the valve, and a pressurized chamber. In one example, the pressurized chamber accommodates the one or more instruments. In one example, the pressurized chamber has a dynamically variable pressure that corresponds to a pressure in a downstream portion of the conduit, such as a natural gas conduit. In another example, the pressurized chamber captures instrument gas that escapes / leaks from the instrument and re-injects the instrument gas into the downstream portion of the conduit.

Description

Technical Field

[0001] The present application relates to a control system with a dynamic reference pressure. Background Art

[0002] Fluid control systems may be used in a variety of industrial, commercial, and other settings to regulate, protect, isolate, or maintain the flow of fluids in pipes, conduits, or other containers and therein (e.g., within a pipeline). In some applications, it may be useful to manage or control the flow of fluids in a pipeline when certain power sources are unavailable. However, typical control systems often exhaust a portion of the controlled fluid (e.g., pipeline gas), which may result in the loss of valuable materials (e.g., natural gas) and may trigger 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, one or more devices in fluid communication with the valve, and a pressurization chamber. In one example, the pressurization chamber accommodates the one or more devices. In one example, the pressurization chamber has a dynamically variable pressure that corresponds to a pressure in a downstream portion of the pipeline, such as a natural gas pipeline.

[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, one or more instruments in fluid communication with the valve, and a pressurization chamber. In one example, the pressurization chamber accommodates the one or more instruments. In one example, the one or more instruments receive instrument gas, which may leak or leak into the pressurization chamber. The pressurization chamber may capture the instrument gas that leaks or leaks from the instrument and re-inject the instrument gas into a downstream portion of the pipeline.

[0005] Some embodiments of the present invention provide a fluid control system. The fluid control system includes a pressurized chamber that is fluidly connected to a pipeline (e.g., a natural gas pipeline) via an exhaust port. In one example, the pressurized chamber accommodates one or more pneumatic instruments. The pressurized chamber can have a dynamically variable pressure corresponding to the pressure in the pipeline. In one example, the one or more instruments within the pressurized chamber have a reference pressure greater than or equal to the pressure of the pipeline. Therefore, instrument gas released by the one or more instruments is captured in the chamber and re-injected into the pipeline via the exhaust port. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0007] Figure 1 is a schematic diagram of an example of a pipeline according to aspects of the present invention.

[0008] Figure 2 is used with Figure 1 A cross-sectional view of an example fluid control system used with piping.

[0009] Figure 3 Is equipped with Figure 2 Fluid control system Figure 1 Schematic diagram of the pipeline.

[0010] Figure 4 is equipped with another example fluid control system Figure 1 Schematic diagram of the pipeline. DETAILED DESCRIPTION

[0011] The following discussion is presented to enable those skilled in the art to make and use embodiments of the present invention. In view of the benefit of this disclosure, those skilled in the art will readily appreciate various modifications to the illustrated embodiments, and the principles herein may be applied to other embodiments and applications without departing from the embodiments of the present invention. Therefore, embodiments of the present invention are not intended to be limited to the illustrated embodiments, but are to be accorded the broadest scope consistent with the principles and features disclosed herein.

[0012] The following detailed description will be read with reference to the accompanying drawings, wherein the same elements in different drawings have the same reference numerals. The accompanying drawings, which are not necessarily drawn to scale, 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.

[0013] 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 construction details and component arrangements 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. And, it should be understood that the words and terms used herein are for illustrative purposes and should not be considered restrictive. The use of "including", "comprising" or "having" and its variants herein is 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 installation, connection, support and connection. In addition, "connect" and "couple" are not limited to physical or mechanical connections or connections.

[0014] As briefly discussed above, fluid control systems can be used in a variety of industrial, commercial, and other environments to control the flow of fluids through pipes, conduits, or other containers. For example, some process systems (including offshore drilling, oil fields, natural gas transmission pipelines, etc.) may (occasionally) require the actuation of valves in remote or difficult-to-access locations. Such remote locations may lack a reliable power source, or may otherwise experience power loss events from time to time, and would therefore benefit from a valve actuation system that has no external power source and no unnecessary loss of fluid (e.g., natural gas).

[0015] Embodiments of the present invention may provide a fluid control system having a pressurized chamber configured to discharge a control fluid (e.g., instrument gas) back into a pipeline without losing the fluid to the atmosphere. In one example, the pressurized chamber has a dynamic pressure and is directly connected to a downstream portion of the pipeline. In other words, the control system may be configured so that the pressure inside the pressurized chamber matches or exceeds the pressure of the downstream portion of the pipeline. Therefore, when the pressure in the downstream pipeline changes, the pressure in the chamber will also change accordingly, and the fluid discharged into the chamber can naturally flow from the chamber back into the pipeline.

[0016] In general, the fluid control systems disclosed herein can be further configured to actuate valves without an external power source. For example, embodiments of the present invention can provide a valve positioner, such as a nozzle flapper type transducer, that is configured to operate without leakage of the control fluid to the atmosphere. Instead, fluid leakage is captured within the pressurized chamber and is exhausted (i.e., re-injected) back into a downstream portion of the pipeline (e.g., downstream of a control valve controlled by the valve positioner). To achieve this, one or more instruments within the pressurized chamber can operate with reference to a "floating" or dynamic reference pressure within the chamber that is based on the pressure in the downstream portion of the pipeline. Thus, these instruments are able to exhaust fluid into the downstream pipeline without exhausting any fluid to the atmosphere.

[0017] In some examples, a pressurized chamber can house instruments (e.g., pneumatic instruments) that are conventionally used at lower pressures (e.g., conventional controllers and positioners). As similarly discussed above, this can be achieved by increasing the pressure surrounding the instrument from atmospheric pressure to a controlled process pressure (typically the pressure of the downstream portion of the pipeline). Since the chamber pressure is equal to (or greater than) the downstream pressure, any fluid consumed by the instrument can be re-injected into the pipeline. This can eliminate venting to atmosphere while still allowing the use of a variety of conventional instruments. For example, in the elevated pressure environment provided by the pressurized chamber, an instrument rated to operate based on a specific pressure differential relative to a standard environment (e.g., standard pressure equal to 1 atmosphere or 14.7 pounds per square inch absolute (PSIA)) can similarly operate at a higher absolute pressure but with the same (rated) pressure differential.

[0018] In other words, the traditional design and operation of pneumatic instruments used in the process control industry is based on a static reference pressure equal to the local atmospheric pressure. These instruments can be integrated into the control system because each instrument has a common reference pressure (e.g., the local atmospheric pressure). The common atmospheric reference pressure also ensures that the gas consumed by the instrument can be discharged when needed. In contrast, in the examples described herein, an alternative reference pressure can be provided to the pneumatic instrument, which can be increased and dynamic in nature. Therefore, for example, when the reference pressure (e.g., the downstream pipeline pressure) fluctuates, the pneumatic instrument pressure can "float" with the reference pressure fluctuations, so that a sufficient pressure differential is maintained to operate the instrument and sufficient output pressure is maintained to re-inject the working fluid into the pipeline. This allows the instrument to provide accurate and responsive control while also allowing discharge to the downstream pipeline, thereby essentially eliminating gas discharge to the atmosphere.

[0019] Figure 1 An example of a pipeline 100 is shown. In one example, the pipeline 100 may be a natural gas pipeline. In one example, the pipeline 100 may include a valve 115 located within the tube of the pipeline 100. The valve 115 may control fluid flow, pressure, or other factors between an upstream portion 105 (relative to the valve 115) and a downstream portion 110 (relative to the valve) of the pipeline 100. The valve 115 may be any of a variety of known types, such as 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 used to modify pipeline pressure or flow. In a specific example, the valve may be a push-down closing valve with a fail-open actuation.

[0020] In the example shown, the valve 115 is in fluid communication with a process fluid (e.g., natural gas, oil, water, or other fluid) flowing through the pipeline 100. The valve 115 can be stroked (i.e., moved / actuated) via the actuator 120 to close, open, or otherwise adjust the position of the valve stem 125 of the valve 115, thereby generating a predetermined fluid pressure or flow rate in the downstream portion 110 of the pipeline 100. In one example (as shown), the actuator 120 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 140 (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 closed". It should be understood that the biasing element 140 can operate the actuator in certain circumstances, such as when the pressure differential (dP) is insufficient to operate the actuator 120.

[0021] In one example, the pipeline 100 includes a fluid control system 130 that includes a fluid powered instrument assembly 134 (e.g., of various known configurations) to control the operation of the valve via the control actuator 120. In one example, the pneumatic instrument can be operated via the use of instrument gas, which can be siphoned or withdrawn from the upstream portion 105 of the pipeline and reinjected into the downstream portion 110 of the pipeline 100 after use. In particular, the fluid control system 130 can operate in a zero-emission state, meaning that the system 130 operates without the loss of gas (e.g., pipeline gas) to the atmosphere. It should be appreciated that such a configuration can help prevent the loss of valuable materials (e.g., via gas loss) and avoid release events that may trigger reporting requirements or other regulatory consequences (e.g., associated with the venting of natural gas to the atmosphere).

[0022] In the illustrated example, to achieve this zero-discharge condition, one or more of the instruments (e.g., positioners, relays, regulators, volume boosters, trip valves, etc.) of the instrument assembly 134 used to control the operation of the valve 115 are contained within a pressurized chamber 132 (e.g., provided using a known type of pressure vessel or other pressure-containing structure). In one example, the control system 130 is designed to float (or dynamically adjust) the internal pressure of the chamber 132 to match or exceed the pressure (P2) in the downstream portion 110 of the pipeline 100. In particular, as discussed further below, the control system 130 can be configured to ensure appropriate input pressure to the instrument assembly 134 so that (e.g., after a known operating pressure drop) the fluid exhausted by the instrument assembly 134 is high enough to be re-injected into the pipeline portion 110 (via natural pressure-driven flow).

[0023] In other words, the pressurized chamber 132 of the control system 130 can be a closed system relative to the atmosphere. Thus, instead of referencing atmospheric pressure, instruments inside the chamber 132 can instead reference the pressure in the downstream portion 110 of the conduit 100. Thus, any instrument gas exhausted or otherwise lost from the control system 130 can be reinjected into the downstream portion 110 of the conduit 100 via the exhaust port 135 (e.g., a simple pipe connection) without further pressurization (and corresponding power requirements). Similarly, the flow of gas between the chamber 132 and the downstream portion 110 of the conduit 100 via the exhaust port 135 enables the chamber 132 and the downstream portion 110 of the conduit 100 to reach equilibrium, wherein the chamber (and instrument reference) pressure changes based on the pressure in the downstream portion 110 of the conduit 100.

[0024] Figure 2A detailed view of an example configuration of an instrument assembly 134 of a fluid control system 130 including one or more instruments (e.g., pneumatic instruments) is shown. As previously mentioned, the fluid control system 130 generally includes one or more instruments configured to adjust the valve 115 (see Figure 1 ) to achieve a predetermined pressure (P2) or flow rate in the downstream portion 110 of the pipeline 100. In one example, the junction box 205 and the controller 210 are located outside the chamber 132. The junction box 205 (e.g., of various known configurations) can be configured to receive one or more electrical connections from one or more sensors, such as valve position sensors, pressure sensors, or other sensors (e.g., see Figure 1 Controller 210 is electrically connected to terminal box 205 and is configured to receive / transmit information from / to one or more sensors (e.g., valve position, downstream pipeline pressure, etc.) and determine whether valve 115 needs to be adjusted. In one example, controller 210 is configured to automatically regulate and / or adjust downstream pipeline pressure (P2) or flow via adjustment of the control valve position.

[0025] In one example, the junction box 205 and the controller 210 are electrically connected to an instrument module 225 within the chamber 132 via a cable 230. In one example, the cable 230 extends through the sidewall 215 of the chamber 132 via a seal 220. In one example, the seal 220 is a hermetic seal configured to prevent the passage of fluids (such as air or other gases) between the atmosphere (e.g., the area outside the chamber 132) and the interior of the chamber 132. In one example, the instrument module 225 includes an i / p converter 235 (e.g., 4 to 20 mA and 3 to 15 PSI) and a pneumatic relay 240. In other examples, the instrument module 225 can include other instruments, such as a volume booster, a trip valve, a regulator, a low-bleed pilot, a positioner, a nozzle flapper transducer, or other instruments. In one example, the i / p converter 235 is a nozzle flapper transducer. The relay 240 may be fluidly connected to the i / p converter 235 within the instrument module 225 to enable controlled routing of instrument gases into the first port 245 or the second port 250 based on instructions received from the controller 210 .

[0026] Within the chamber 132 of the fluid control system 130, the regulator input line 255 supplies the instrument gas to the input port 260 of the supply regulator 265, which is configured to regulate the pressure of the instrument gas. For example, the regulator 265 can regulate the gas pressure from the regulator input line 255 to ensure a predetermined pressure differential value for operation of the instrument module 225 so that the exhaust gas can still be re-injected into the pipeline 100. Therefore, in one example, the supply regulator 265 references the pressure in the downstream portion 110 of the pipeline 100 rather than the atmospheric pressure. Correspondingly, in one example, the supply regulator 265 can have a pressure set point relative to a dynamic reference pressure (i.e., the pressure in the downstream portion of the pipeline (P2)).

[0027] The supply regulator 265 can output the regulated instrument gas into the output supply line 275 via the output port 270. The output supply line 275 is connected to the input port 280 on the instrument module 225 to supply the pressure regulated gas to the instrument module 225. In one example, the pressure regulated gas flows through the i / p converter 235 and the relay 240 based on the electrical signal sent from the controller 210 to the instrument module 225. Therefore, the gas from the supply regulator 265 is directed by the relay 240 through the first port 245 or the second port 250 based on the electrical signal sent from the controller 210. It should be understood that applying gas to the first port 245 or the second port 250 can adjust the actuator 120 (see Figure 1 ) position, which can modify the pressure and / or flow within the downstream portion 110 of the pipeline 100.

[0028] In some examples, the i / p converter 235 may experience a leak (e.g., a constant leak) that causes the instrument gas to escape. In this case, the leaked instrument gas is released into the chamber 132. In one example, since the reference pressure within the chamber 132 is based on the downstream pipeline pressure (P2), the leaked gas is at a pressure greater than or equal to the pressure in the downstream portion 110 of the pipeline 100. Therefore, the leaked instrument gas can flow through the opening 290 in the side wall 215 of the pressurized chamber 132 to be re-injected into the downstream portion 110 of the pipeline 100 via the exhaust port 135. Therefore, no gas is released to the atmosphere, thereby helping to save costs and comply with relevant regulations.

[0029] exist Figure 3 In the example shown, the following are installed: Figure 2 The apparatus assembly 134 is configured as in Figure 1130. Thus, for example, the supply regulator 265 receives the instrument gas from the upstream portion 105 of the pipeline 100 via the supply line 305. In some examples, the supply line 305 may include a regulator 310 (e.g., a high pressure regulator) configured to reduce or otherwise regulate the pressure in the supply line 305 to a predetermined pressure value. In one example, the predetermined pressure value is a calculated value equal to the maximum allowable operating pressure (MOAP) of the downstream portion 110 of the pipeline 100 plus the operating pressure differential of the actuator 120 (via the instrument assembly 134) plus a safety factor (e.g., 2 to 15 PSI). In one example, the regulator 310 may include a monitoring line 315 configured to monitor the pressure in the supply line 305 just downstream of the regulator 310. In one example, the regulator 310 may self-regulate or adjust based on the pressure monitored by the monitoring line 315.

[0030] As previously mentioned, the controller 210 is configured to monitor the position of the actuator 120 and the pressure in the downstream portion 110 of the pipeline 100 to determine whether the valve 115 needs to be adjusted. In one example, the junction box 205 and the controller 210 are positioned outside the chamber 132 (i.e., exposed to atmospheric pressure / reference atmospheric pressure). In one example, the junction box 205 is electrically connected (e.g., hardwired and / or wirelessly connected) to the pressure transducer 320 and the stroke transducer 325. The pressure transducer 320 is configured to monitor and report the pressure (P2) in the downstream portion 110 of the pipeline 100. The stroke transducer 325 is configured to monitor and report the position of the actuator 120 (corresponding to the position of the valve 115). In one example, the pressure transducer 320 is positioned outside the pressurized chamber 132 to provide a gauge pressure reading (relative to atmospheric pressure) of the downstream portion 110.

[0031] In one example, the instrument module 225 is connected to the first line 335 and the second line 330 via the first port 245 and the second port 250 such that the relay 240 (see Figure 2) controls the flow of instrument gas into the first line 335 or the second line 330. In the example shown, the flow of instrument gas into the first line 335 supplies gas to the first side 345 of the actuator 120, which restricts the flow of gas through the valve 115 (e.g., closes the valve 115). Similarly, the flow of instrument gas into the second line 330 supplies gas to the second side 340 of the actuator 120 (i.e., the side containing the biasing element 140), which increases the flow of gas through the valve 115 (e.g., opens the valve 115). Throughout the valve actuation process, the controller 210 can monitor the pressure transducer 320 and the travel transducer 325. During such actuation, as also discussed above, any working gas exhausted from the instrument is captured within the chamber 132 and exhausted into the downstream portion 110 of the pipeline via the exhaust port 135. Thus, the control system 130 operates in a zero-emission state with no gas lost to the atmosphere.

[0032] Figure 4 Shows that it can be Figure 1 Another example of a fluid control system 400 for use with the pipeline 100 of the embodiment of the present invention (e.g., as an alternative configuration of the fluid control system 130). As will be appreciated, the fluid control system 400 shares a number of 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, unless otherwise indicated, the previous discussion of commonly named or numbered features also applies to the example configuration of the fluid control system 400.

[0033] In some cases, the fluid control system 400 may include a differential pressure regulator 405 disposed on an atmospheric vent 410. The atmospheric vent 410 may be configured to allow fluid (e.g., control fluid or instrument gas) to selectively vent to the atmosphere (e.g., during periods when the pressure differential is insufficient to operate one or more instruments). In one example, the control system 400 may automatically transition from a zero-vent state (e.g., the regulator 405 is closed) to a vent state (e.g., the regulator 405 is open) without operator intervention or external power.

[0034] In one example, the atmospheric exhaust port 410 may extend from an exhaust port 415 (e.g., similar to the exhaust port 135 previously described). The differential pressure regulator 405 may selectively permit or inhibit the flow of fluid from the exhaust port 415 to the atmosphere based on one or more pipeline conditions. For example, when the pressure differential is insufficient to operate the actuator 120 (e.g., the pressure in the upstream portion 105 of the pipeline 100 is substantially similar to the pressure in the downstream portion 110 of the pipeline 100), the differential pressure regulator 405 may permit the flow of fluid from the exhaust port 415 to the atmosphere (e.g., open the regulator 405). In another example, the differential pressure regulator 405 may permit the flow of fluid from the exhaust port 415 to the atmosphere during high demand periods (e.g., during winter or other extreme weather conditions). In yet another example, when there is a sufficient pressure differential between the upstream portion 105 of the pipeline 100 and the downstream portion 110 of the pipeline 100, the differential pressure regulator 405 may inhibit the flow of fluid from the exhaust port 415 to the atmosphere (e.g., close the regulator 405). In this case, the fluid control system 400 may be operated in a zero-discharge state, wherein fluid from the pressurized chamber 132 passes through the exhaust port 415 and is reinjected into the downstream portion 110 of the pipeline 100 .

[0035] In one example, the differential pressure regulator 405 includes a first monitoring line 420 and a second monitoring line 425. The first monitoring line 420 is configured to monitor the pressure in the supply line 305 (e.g., the instrument supply line), which corresponds to the pressure in the upstream portion 105 of the pipeline 100. Correspondingly, the second monitoring line 425 is configured to monitor the pressure in the exhaust port 415, which corresponds to the pressure in the downstream portion 110 of the pipeline 100. Therefore, when the pressure in the supply line 305 is sufficiently greater than the pressure in the exhaust port 415 (e.g., the pressure differential is sufficient), the regulator 405 is closed and the fluid is not exhausted to the atmosphere. However, when the pressure in the supply line 305 is not sufficiently greater than the pressure in the exhaust port 415 (e.g., the pressure differential is insufficient), the regulator 405 is opened and the fluid is exhausted to the atmosphere until a sufficient pressure differential value is reached. Once a sufficient pressure differential value is reached between the supply line 305 and the exhaust port 415, the regulator 405 can automatically close.

[0036] In one example, the differential pressure regulator 405 can include an adjustable biasing element 430 configured to enable a user to adjust a pressure set point of the differential pressure regulator 405. In one example, the biasing element 430 can be configured to bias the differential pressure regulator 405 to an open position such that fluid is permitted to flow from the exhaust port 415 to the atmosphere. In other words, the set point of the regulator 405 can be adjusted via the biasing element 430, and the set point can correspond to the pressure in the supply line 305 required to close the regulator 405 (e.g., inhibit fluid from flowing from the exhaust port 415 to the atmosphere). In another example, the set point of the regulator 405 can be adjusted via the biasing element 430, and the set point can correspond to a minimum pressure differential required to operate the actuator 120.

[0037] To prevent fluid from inadvertently flowing (e.g., releasing) from the downstream portion 110 of the pipeline 100 to the atmosphere via the atmospheric exhaust port 410, the exhaust port 415 may include a check valve 435 disposed within the exhaust port 410. In one example, the check valve 435 may allow one-way flow of fluid from the exhaust port 415 into the downstream portion 110 of the pipeline 100, but may limit or inhibit the flow of fluid from the downstream portion 110 of the pipeline 100 into the exhaust port 415. In one specific example, the check valve 435 may be positioned within the exhaust port 415 between the atmospheric exhaust port 410 and the downstream portion 110 of the pipeline 100.

[0038] In some implementations, the devices or systems disclosed herein may be utilized, manufactured, or installed using methods that embody 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 for using such a device for its intended purpose, methods for otherwise achieving such capabilities, methods for manufacturing related components of such a device or system (or the device or system as a whole), and methods for installing disclosed (or otherwise known) components to support such purposes or functions. Similarly, unless otherwise indicated or limited, discussion herein of any method for manufacturing or using a particular device or system (including installing the device or system) is intended to inherently include disclosure of features utilized and capabilities achieved by such a device or system as an embodiment of the present invention.

[0039] Also as used herein, unless otherwise limited or defined, "or" represents a non-exclusive list of components or operations that can exist in any variety of combinations, rather than an exclusive list of components that can exist only as alternatives to each other. For example, a list of "A, B, or C" indicates the following options: A; B; C; A and B; A and C; B and C; and A and B and C. Correspondingly, the term "or" as used herein is intended to indicate exclusive alternatives only when preceded by an exclusive term such as "any," "one," "only one," or "exactly one." For example, a list of "one of A, B, or C" indicates the following options: A, but not B and C; B, but not A and C; and C, but not A and B. A list that begins with "one or more" (and variations thereof) and includes "or" to separate the listed elements represents an option of one or more of 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" indicate 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 A, one or more B, and one or more C. Similarly, a list beginning with "plurality" (and variations thereof) and including "or" to separate the listed elements indicates the option of multiple instances of any 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" indicate the following options: A and B; B and C; A and C; and A, B, and C.

[0040] As used herein, unless otherwise defined or limited, directional terminology is used for ease of reference for discussion of a particular figure or example. For example, references to a downward (or other) direction or a top (or other) position may be used to discuss aspects of a particular example or figure, but similar orientations or geometries are not necessarily required in all installations or configurations.

[0041] Also as used herein, unless otherwise limited or defined, "substantially parallel" refers to a direction within ±12 degrees (e.g., within ±6 degrees) of a reference direction, including that direction. For a nonlinear path, a path may be considered substantially parallel to a reference direction if a straight line between the endpoints of the path is substantially parallel to the reference direction, or if the average derivative of the path within a common reference frame serving as the reference direction is substantially parallel to the reference direction.

[0042] Also as used herein, unless otherwise limited or defined, "substantially perpendicular" refers to a direction within ±12 degrees (e.g., within ±6 degrees) of being perpendicular to a reference direction, including that direction. For a nonlinear path, a path may be considered substantially perpendicular to a reference direction if a straight line between the path endpoints is substantially perpendicular to the reference direction, or if the average derivative of the path within a common reference frame serving as the reference direction is substantially perpendicular to the reference direction.

[0043] 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, etc., securing the separate components together. For example, an element that is formed from a single piece of sheet metal or stamped, cast, or otherwise molded into a single-piece component using a single die, without rivets, screws, or adhesives securing the separately formed pieces together, is an integral (and integrally formed) element. In contrast, an element that is formed from multiple pieces that are initially formed separately and then later joined together is not an integral (or integrally formed) element.

[0044] Additionally, unless otherwise specified or limited, the terms "approximately" and "approximately" used herein with respect to a reference value refer to a variation of ±15% or less from 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 variation of less than ±30% from the reference value, including the endpoints. Where specified, "substantially" may particularly refer to a variation in a numerical direction relative to the reference value. For example, "substantially less than" a reference value (and similar terms) indicates a value that is reduced by 30% or more from the reference value, and "substantially greater than" a reference value (and similar terms) indicates a value that is increased by 30% or more from the reference value.

[0045] 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 processes and specifications, where the variations between the components or systems are within the limits of acceptable tolerances for the relevant processes and specifications. For example, if two components are manufactured according to the same standardized manufacturing steps, with the same materials, and within the same acceptable dimensional tolerances (e.g., as specified for a particular process or product), then the components may be considered substantially the same.

[0046] The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. In view of the benefit of this disclosure, various modifications of these embodiments will be readily apparent to those skilled in the art, and the principles defined herein may be applied to other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not intended to be limited to the embodiments shown herein, but should be given the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A fluid control system, comprising: valve; one or more instruments in fluid communication with the valve; as well as Compression chamber; wherein the one or more instruments are positioned within the pressurized chamber; and Wherein the pressurized chamber has a dynamically variable pressure corresponding to the pressure in the downstream portion of the conduit.

2. The system of claim 1, wherein the one or more instruments within the pressurized chamber have a reference pressure that is greater than or equal to the pressure in the downstream portion of the conduit.

3. The system of claim 1, wherein the one or more instruments within the pressurized chamber receive supply gas from a supply regulator positioned within the pressurized chamber. 4 . The system of claim 3 , wherein the supply regulator receives input gas from an upstream portion of the pipeline via a supply line.

5. The system of claim 1, wherein the one or more instruments comprise a nozzle-flapper transducer.

6. The system of claim 1 , wherein instrument gases leaking from the one or more instruments are captured within the chamber and reinjected into the downstream portion of the conduit via an exhaust port connecting the pressurized chamber and the downstream portion of the conduit.

7. The system of claim 1, further comprising: a controller electrically connected between the valve and the one or more instruments within the pressurization chamber; Wherein the controller is positioned outside the pressurized chamber.

8. A fluid control system, comprising: valve; one or more instruments in fluid communication with the valve; as well as a pressurization chamber fluidly connected to the downstream portion of the conduit; wherein the one or more instruments are positioned within the pressurized chamber; and Wherein instrument gases released by the one or more instruments are captured within the chamber and reinjected into the downstream portion of the conduit.

9. The system of claim 8, wherein the pressurized chamber has a dynamically variable pressure corresponding to the pressure in the downstream portion of the conduit.

10. The system of claim 9, wherein the one or more instruments within the pressurized chamber have a reference pressure greater than or equal to the pressure in the downstream portion of the conduit.

11. The system of claim 8, wherein the one or more instruments within the pressurized chamber receive a supply gas from a supply regulator positioned within the pressurized chamber.

12. The system of claim 11, wherein the supply regulator receives input gas from an upstream portion of the pipeline via a supply line.

13. The system of claim 8, wherein the one or more instruments include a nozzle-flapper transducer.

14. The system of claim 8, further comprising: a controller electrically connected between the valve and the one or more instruments within the pressurization chamber; Wherein the controller is positioned outside the pressurized chamber.

15. A fluid control system, comprising: a pressurized chamber fluidly connected to the conduit via a discharge port; as well as one or more pneumatic instruments, the one or more pneumatic instruments being held within the chamber; wherein the pressurized chamber has a dynamically variable pressure corresponding to the pressure in the conduit; wherein the one or more instruments within the pressurized chamber have a reference pressure greater than or equal to the pressure of the conduit; and Wherein instrument gases released by the one or more instruments are captured within the chamber and reinjected into the conduit via the exhaust port.

16. The system of claim 15, further comprising: a valve in the conduit; wherein the valve divides the conduit into an upstream portion and a downstream portion; wherein the upstream portion is upstream of the valve; and Wherein the downstream portion is downstream of the valve.

17. The system of claim 16, wherein the one or more instruments within the pressurized chamber receive a supply gas from a supply regulator positioned within the pressurized chamber.

18. The system of claim 17, wherein the supply regulator receives input gas from an upstream portion of the pipeline via a supply line.

19. The system of claim 15, wherein the one or more instruments comprise a nozzle-flapper transducer.

20. The system of claim 16, wherein the instrument gas is reinjected into the downstream portion of the conduit via an exhaust port.

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