Double-walled cylinder for fluid control device actuator

Abstract

A fluid control device can include an actuator having a first cylinder defining a maximum differential pressure of the actuator, a second cylinder circumferentially surrounding the first cylinder, the second cylinder defining a maximum rated pressure of the actuator, and a piston disposed within the first cylinder to translate within the first cylinder in response to pressures within the first cylinder and the second cylinder to control operation of the fluid control device.

Description

Background Technology

[0001] Fluid control devices, such as control valves, are used in a variety of industrial, commercial, and other applications to regulate, protect, isolate, or maintain fluid flow in pipes, conduits, or other tubular devices and within them (e.g., pipelines). However, typical fluid control systems can be costly to manufacture or maintain. Furthermore, typical fluid control systems often include instrumentation systems, which can be complex to assemble, especially in retrofit applications. Summary of the Invention

[0002] Some aspects of this disclosure provide an actuator for a fluid control device such as a valve. The actuator may include: a cylinder assembly having an inner cylinder and an outer cylinder, wherein the outer cylinder circumferentially surrounds the inner cylinder to form a radial clearance between the inner and outer cylinders; a first end cap fixed to a first end of the cylinder assembly to close the first end of the inner cylinder and the first end of the outer cylinder; a second end cap fixed to a second end of the cylinder assembly opposite to the first end of the cylinder assembly to close the second end of the inner cylinder and the second end of the outer cylinder; and a piston disposed within the inner cylinder, the piston being translatable within the inner cylinder in response to a pressure difference across the piston within the inner cylinder to actuate the valve.

[0003] Some aspects of this disclosure provide a method of operating a fluid control device. The method may include controlling a drive fluid flow in an actuator comprising a first cylinder and a second cylinder, wherein the second cylinder circumferentially surrounds the first cylinder to form a gap between the first and second cylinders, thereby selectively moving a piston within the first cylinder in a first direction by guiding the drive fluid flow through the gap between the first and second cylinders and into an internal volume of the first cylinder on a first side of the piston, and selectively moving the piston within the first cylinder in a second direction by guiding the drive fluid flow into an internal volume of the first cylinder on a second side of the piston.

[0004] Some aspects of this disclosure provide a fluid control device that may include an actuator having: a first cylinder defining a maximum differential pressure of a valve actuator; a second cylinder circumferentially surrounding the first cylinder and defining a maximum rated pressure of the actuator; and a piston disposed within the first cylinder to translate within the first cylinder in response to pressures within the first and second cylinders, thereby controlling operation of the fluid control device. Attached Figure Description

[0005] The accompanying drawings, which are incorporated in and form a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of these embodiments:

[0006] Figure 1 This is a perspective view of an example of a fluid control device according to this disclosure.

[0007] Figure 2 yes Figure 1 A cross-sectional view of an example actuator for a fluid control device.

[0008] Figure 3 yes Figure 2 A cross-sectional view of an example of the cylinder of the actuator.

[0009] Figure 4 yes Figure 2 A cross-sectional view of another example of the actuator cylinder, wherein the piston of the actuator is in the first position.

[0010] Figure 5 yes Figure 4 A cross-sectional view of the cylinder, in which the piston is in the second position.

[0011] Figure 6 It is for supply Figure 2 An isometric view of an example of an instrument mounting system used for the actuator cylinder.

[0012] Figure 7 It is assembled in Figure 2 On the cylinder of the actuator Figure 6 A cross-sectional view of the instrument installation system.

[0013] Figure 8 It is for supply Figure 2 Another example of an isometric view of the instrument mounting system used in the cylinder of the actuator.

[0014] Figure 9 It is fixed to Figure 4-5 On the cylinder Figure 8 A cross-sectional view of the instrument installation system.

[0015] Figure 10 It is fixed to Figure 4-5 A cross-sectional view of another example of an instrument mounting system on a cylinder. Detailed Implementation

[0016] The following discussion is presented to enable those skilled in the art to make and use embodiments of the invention. Based on the benefits of this disclosure, various modifications to the illustrated embodiments will be apparent to those skilled in the art, and the principles herein can be applied to other embodiments and applications without departing from the embodiments of the invention. Therefore, embodiments of the invention are not intended to be limited to the illustrated embodiments, but should be given the broadest scope consistent with the principles and features disclosed herein.

[0017] The following detailed description should be read with reference to the accompanying drawings, in which similar elements in different figures have similar reference numerals. The drawings, not drawn to scale, depict selected embodiments and are not intended to limit the scope of the embodiments of the invention. Those skilled in the art will recognize that the examples provided herein have many useful alternatives and fall within the scope of the embodiments of the invention.

[0018] Before explaining any embodiments of the invention in detail, it should be understood that the invention, in its application, is not limited to the construction details and component arrangements set forth in the following description or illustrated in the accompanying drawings. The invention may have other embodiments and may be practiced or performed in various ways. Furthermore, it should be understood that the wording and terminology used herein are for descriptive purposes and should not be considered limiting. The terms “including,” “comprising,” or “having,” and variations thereof, as used herein, are intended to cover the items listed thereafter and their equivalents, as well as additional items. Unless otherwise specified or limited, the terms “installation,” “connection,” “support,” “linkage,” and variations thereof are used broadly and cover both direct and indirect installation, connection, support, and linking. Furthermore, “connection” and “linkage” are not limited to physical or mechanical connections or links.

[0019] As briefly discussed above, fluid control systems can be used in a variety of industrial, commercial, and other applications to control the flow of fluid through pipes, conduits, or other tubular structures. Therefore, the control valves discussed herein may include actuators with cylinders (e.g., pneumatic cylinders operating at 150 PSI or lower). The cylinder may include a piston configured to move in response to a force applied via a pressurized fluid drive flow to operate the valve actuator (e.g., to move a valve stem to open / close a valve). For example, the drive flow may be an instrumentation gas flow (i.e., gas received from a known pneumatic flow control instrument), which may in turn originate from pressurized line gas, a compressed air source, or other sources, and be controllably directed to move the piston in the opening or closing direction.

[0020] The cylinder assembly can be a double-walled cylinder having a first inner cylinder and a second outer cylinder. In some examples, the inner cylinder may be made of a first material (e.g., various polymer materials) having a first yield strength, and the outer cylinder may be made of a different second material (e.g., steel or other metallic materials) having a different yield strength. For example, the inner cylinder may be made of a commercially available material designed for low-pressure operation, while the outer cylinder may be made of a commercially available material designed for high-pressure operation. Thus, the material strength of the outer cylinder may be higher than that of the inner cylinder, correspondingly resulting in a difference in the rated pressure of cylinders with similar wall thickness and diameter.

[0021] Furthermore, the outer cylinder can be arranged to surround the inner cylinder and contain fluid at a reference pressure (or multiple pressures). Thus, the outer cylinder can be configured to set the maximum operating pressure, while the rated pressure of the inner cylinder (when used alone) can correspond to the maximum differential pressure of the actuator (e.g., a relatively low value set by various known actuator controllers). Therefore, due to the dual-cylinder arrangement, even in relatively high-pressure pipeline applications (e.g., when relatively high-pressure pipeline gas is supplied as instrument gas to operate the actuator), a relatively weak (e.g., low-pressure) inner cylinder material can be used, providing an economical option for the cylinder arrangement. Additionally, the dual-cylinder arrangement can accommodate the inner cylinder such that in the event of a catastrophic failure of the inner cylinder, the inner cylinder (e.g., fragments) is contained within the outer cylinder.

[0022] In another example, the fluid control device may include an instrument mounting system. For example, the cylinder may include a removable cover that can be removed and replaced using one or more fasteners. In some examples, the cover may serve as a mounting site for one or more pressure relief valves (e.g., for maintaining a predetermined pressure differential). In some examples, the cover may serve as a mounting site for one or more instruments of a valve (e.g., instruments known in the art for amplifying or directing drive flow to cause specific movement of a piston or other actuator component). Thus, the instrument can be mounted directly to the cover, rather than mounted elsewhere and connected to related actuator parts via complex piping arrangements. In this arrangement, the instrument and cover can form an integral assembly that is jointly mounted to the cylinder, wherein the cover secures the attached instrument to the cylinder, supports the attached instrument relative to the cylinder, or provides a flow path for the drive fluid flow between the instrument and the cylinder. This configuration can make the replacement or repair of the instrument or cover easier, without requiring the installer to deal with complex piping issues.

[0023] Furthermore, in some examples, the cover or other instrumentation mounting system may form a pressurized chamber configured to allow instrument gas to be discharged back into the line (or other pressurized fluid pool) without loss of instrument gas to the atmosphere (e.g., no discharge of line gas used to operate actuators via the instrumentation). In one example, the pressurized chamber has dynamic pressure and is fluidly connected (i.e., in fluid communication) to a downstream portion of the line. Therefore, when the pressure in the downstream line changes, the pressure in the chamber can change accordingly, and fluid discharged (e.g., via one or more instruments) into the chamber can naturally flow back from the chamber into the line.

[0024] Figure 1 and Figure 2The illustration depicts an example of a fluid control device (e.g., a control valve, damper, etc.) for use in natural gas or other pipelines. In one particular example, the fluid control device may be in the form of valve 100, which controls the fluid flow rate, pressure drop, or other coefficients between an upstream portion or inlet 120 (relative to valve 100) and a downstream portion or outlet 125 (relative to valve 100) of the pipeline. Valve 100 can be any of a variety of known types, such as a ball valve, gate valve, butterfly valve, diaphragm valve, globe valve, plug valve, check valve, or any other type of valve used to modify pipeline pressure or flow. In one particular example, the valve may be a push-to-close valve with a fail-open actuation mode.

[0025] In some examples, valve 100 may be in fluid communication with a process fluid (e.g., natural gas, oil, water, or other fluid) flowing through the pipeline. Valve 100 may be traveled (i.e., moved / actuated) by actuator 110 (e.g., an attached actuator portion) to close, open, or otherwise regulate the position of valve stem 130 within valve body 115, thereby generating a predetermined pressure or flow rate of fluid in a downstream portion of the pipeline. In some examples, actuator 110 may include cylinder 135 having a piston 205 configured to actuate valve stem 130 and a corresponding piston rod 210 (or other pressure-movable assembly). For example, piston rod 210 may be connected to valve stem 130 via valve stem connector 215 disposed within yoke 140 of actuator 110.

[0026] In some examples, actuator 110 may be a double-acting piston actuator. In other examples, actuator 110 may be a single-acting piston actuator, or may have other known configurations. In some examples, the actuator may include a biasing element 220 (e.g., a spring) within housing 145, and the biasing element 220 is configured to cause the actuator to "open in case of failure". In other examples, the biasing element may be positioned or configured to cause the actuator to "close in case of failure". As should be understood, the biasing element 220 may operate the actuator in certain situations, such as when the differential pressure (dP) is insufficient to operate actuator 110.

[0027] In one example, valve 100 can be actuated using instrument gas diverted from the pipeline to operate actuator 110. In other examples, valve 100 can be actuated using instrument gas from one or more air compressors (e.g., separate from the pipeline). In some specific examples, when using instrument gas from the pipeline, the instrument gas can be reinjected downstream of the pipeline after use. Therefore, control valve 100 can operate in a zero-emission state, meaning the valve operates without losing drive fluid (e.g., pipeline gas) to the atmosphere. As should be understood, this configuration helps prevent the loss of valuable materials (e.g., via gas loss) and avoids leakage events (e.g., involving the release of natural gas into the atmosphere) that could trigger reporting requirements or other regulatory consequences.

[0028] Figure 3 An example of an actuator including a cylinder assembly 300 for use with the valve 100 discussed earlier is shown. As shown, the cylinder assembly 300 may include a double-walled arrangement in which a first inner cylinder 305 is surrounded by a second outer cylinder 310. Specifically, the outer cylinder 310 has an inner diameter larger than the outer diameter of the inner cylinder 305, such that a radial clearance (i.e., a clearance in the radial direction) extends circumferentially between the two cylinders 305, 310. In some examples, this double-walled configuration may permit the use of relatively weak materials with other beneficial operating properties (e.g., sealing properties, frictional properties, etc.) for the actuator operated by a relatively high pressure input (e.g., operated by transferred pipeline gas in unpowered or remote locations).

[0029] Specifically, due to the double-wall arrangement, the maximum rated operating pressure of the cylinder assembly 300 can be set to a relatively high value via the outer cylinder 310, while the inner cylinder 305 can be operated by a relatively high input pressure but only subjected to a relatively small net pressure load (e.g., differential pressure). For example, for a line actuator, with the radial clearance pressurized to the downstream line pressure (e.g., 1500 PSI), the inner cylinder 305 can be sized (e.g., in radial thickness) to operate at a pressure slightly higher than the downstream line pressure, which provides a differential pressure (dP). In some examples, the inner cylinder 305 can be sized to accommodate a differential pressure of up to about 150 PSI. Therefore, for example, improved operating characteristics of the inner cylinder 305 (e.g., reduced friction or corrosion operation) can be obtained by using composite materials without requiring excessively high material thickness to accommodate the relatively high input pressure received from the line (or other input source).

[0030] In some examples, the inner cylinder 305 may be formed of a fiber-reinforced composite material (e.g., integrally molded as a pipe) or other composite materials (i.e., polymeric materials, non-metallic materials). In some examples, the composite material may include an underlying substrate (e.g., fiber-reinforced epoxy resin) and incorporate various surface treatments to provide a support surface for the actuator piston. For example, the inner wall of the actuator cylinder may be formed on a mandrel, coated with a gel, or otherwise subjected to known surface treatments (e.g., honing, etc.) to provide reduced friction or increased corrosion resistance compared to the underlying composite substrate (e.g., an underlying fiber-reinforced composite pipe). In some examples, the inner cylinder (or other cylinder) may be formed of a fiber-reinforced thermosetting epoxy resin (e.g., a product currently sold by Amalga Composites under the brand name (or trademark) Black Amalgon) or other reinforced composite materials, while the outer cylinder (or other cylinder) may be formed of a relatively stronger material (e.g., steel or other metallic materials). For example, the outer cylinder may be formed of a material that matches the downstream piping material (e.g., ASTM A106 Class B steel). This configuration can be advantageous because the inner cylinder material can be low-friction, lightweight, durable, and corrosion-resistant. However, a relatively strong outer cylinder can provide additional structural strength and fire resistance to the cylinder assembly 300. Furthermore, the outer cylinder may not require honing or other surface treatments, which reduces overall cost and improves manufacturing efficiency. In other examples, it should be understood that the inner and outer cylinders can be made of the same material (e.g., composite materials, metallic materials, etc.). For example, both the inner and outer cylinders can be made of the same material, but the inner cylinder has a relatively thinner wall thickness compared to the outer cylinder. In other examples, the inner and outer cylinders can be identical, with a consistent wall thickness between the inner and outer cylinders.

[0031] In some examples, to form a double-walled arrangement, the inner cylinder 305 and the outer cylinder 310 may be fixed (e.g., clamped) between a pair of end caps (e.g., a first end cap 315 and a second end cap 320). For example, the inner and outer cylinders may be clamped between the respective inner surfaces 385 of the end caps 315, 320 using one or more pull rods 380. In some examples, to reduce the risk of damage to the inner cylinder 305, the end caps 315, 320 may apply clamping force only to the outer cylinder 310, or the clamping force applied to the outer cylinder may be much greater than the clamping force simultaneously applied to the inner cylinder. In other words, most of the clamping stress may be borne by the stronger outer cylinder 310, rather than the inner cylinder 305. For example, the clamping force applied to the inner cylinder may be lower than the longitudinal compressive strength of the inner cylinder material (e.g., 20 kPSI), which may be relatively less than the longitudinal compressive strength of the outer cylinder material. In addition, in some examples, due to the double-wall arrangement, only the internal cylinder 305 may be sealed relative to the piston 205, which reduces the need for machining or honing of the external cylinder 310 and correspondingly reduces the manufacturing cost of the cylinder assembly 300.

[0032] In some examples, the cylinder may include a cover 375 positioned on the side of the second end cap 320 opposite to the cylinders 305, 310. In some examples, the pull rod 380 may pass through the cover 375 in addition to passing through the end caps 315, 320, to secure the cover in place. For example, the end cap 320 may be clamped between the cover 375 and the cylinders 305, 310, such that the cover 375 seals the internal volume of the cylinder. In some cases, the cover 375 may alternatively be formed as an end cap, or may be included in an integral assembly including the end cap (e.g., as discussed further below).

[0033] In some examples, cover 375 may serve as a mounting location for various instrument connections, such as those for supplying instrument gas or other driving fluids to cylinder assembly 300. In a particular example, the cover may form an integrated instrument mounting system 390, which may include one or more integrated instrument ports to provide fluid communication between the instruments and the internal volumes of cylinders 305, 310. For example, integrated instrument mounting system 390 may include ports 377, 379 providing mounting locations for air connections 330, 355. Correspondingly, port 377 may provide a path for instrument gas to flow into the internal volume of internal cylinder 305 on a first side of piston 205, while port 379 may provide a path for instrument gas to flow into the internal volume of internal cylinder 305 on a second side of piston 205, as also described in further detail below.

[0034] Typically, ports 377 and 379 are in fluid communication with opposite sides of piston 205, respectively, to allow selective movement of piston 205 via a controlled flow of actuating fluid through ports 377 and 379. In some examples, for operating a valve (e.g., via movement of piston 205 within cylinder assembly 300), inner cylinder 305 may include one or more perforations 345 circumferentially surrounding a first end of inner cylinder 305. Perforations 345 allow fluid (e.g., instrument gas) to flow into the internal volume of inner cylinder 305. In some examples, the piston divides the internal volume of inner cylinder 305 into a first internal volume 350B and a second internal volume 350A, both of which together define the internal volume of inner cylinder 305 (e.g., in a double-acting piston actuator). For example, perforation 345 allows fluid to flow into the first internal volume 350B on a first side 322 of piston 205. For example, this allows the instrument gas to apply force to the piston 205 in the direction indicated by arrow 395 (e.g., corresponding to opening valve 100).

[0035] As also noted above, in some examples, a gap 325 may be formed between the inner cylinder 305 and the outer cylinder 310 due to the diameter difference between them. Therefore, instrument gas can enter from the air connector 330 into the circumferential channel 335 (e.g., an internally formed recess) of the cover 375. The instrument gas can then flow along the channel 335 and through one or more orifices 340 (e.g., circumferentially arranged) in the second end cap 320, which can correspondingly guide the instrument gas into the gap 325 between the inner and outer cylinders. The instrument gas can then enter from the gap 325 through the perforation 345 into the first internal volume 350B of the inner cylinder 305 on the first side 322 of the piston, and apply pressure to the first side of the piston 205. Correspondingly, the piston can move in the direction indicated by arrow 399, while the exhaust flow can pass through the opening 365 in the second end cap 320 (e.g., exiting the second internal volume on the second side of the piston).

[0036] In some examples, instrument gas can be supplied via air connection 355 to move piston 205 in the opposite direction to that shown by arrow 395 (e.g., to close valve 100). For example, instrument gas can enter from air connection 355 into a central channel 360 within cap 375. The instrument gas can then pass from central channel 360 through a central (or other) opening 365 in second end cap 320, which can guide the instrument gas into the internal volume of internal cylinder 305. For example, the instrument gas can enter through opening 365 into a second internal volume 350A on the second side 324 of piston 205, and thus exert force on the second side of piston 205. Correspondingly, piston can move in the direction shown by arrow 397 while exhaust flow can pass through a gap (e.g., exiting the first internal volume on the first side of piston).

[0037] Figure 4 and Figure 5 The diagram shows the available Figure 1 Another example of a cylinder assembly 400 used by the control valve 100 (e.g., as an alternative configuration to cylinder assembly 300). As will be appreciated, cylinder assembly 400 shares many components with the previously illustrated and described examples and operates in a similar manner. For the sake of brevity, these shared features will not be described in detail below. Rather, unless otherwise indicated, the previous discussion of features with shared names or numbers applies equally to the example configuration of cylinder assembly 400.

[0038] As previously mentioned, in some examples, due to the double-walled arrangement of the cylinders, the differential pressure rating of the outer cylinder can be adjusted independently of the differential pressure rating of the inner cylinder. In some examples, the cylinder pressure rating can be adjusted to match the maximum pressure rating of the downstream line, which allows instrument gas to be vented (e.g., reintroduced) from the cylinder to the downstream line (e.g., to provide a zero-emission system). In a particular example, such as Figure 4 As shown, with Figure 3 Compared to the external cylinder, the external cylinder 405 can be made of a material with a relatively higher rated pressure. For example, the external cylinder 405 can be made of 100# steel tubing, which can provide a rated pressure of approximately 1500 PSI for the cylinder assembly 400. Furthermore, due to the increased wall thickness of the external cylinder 405, the end caps 315, 320 and the cover (e.g., cover 410) can be secured via one or more bolts or other threaded fasteners 440, instead of using a pull rod 380.

[0039] In some examples, when piston 205 is in the first position, piston 205 contacts the end stop 435 of the second end cap 320 (e.g., as shown in the image). Figure 4 As shown) or other end stops, the pressure within the gap 325 is approximately equal to the pressure within the first internal volume 350B of the internal cylinder 305 on the first side 322 of the piston 205, wherein the pressure difference across the wall of the internal cylinder is correspondingly equal to or close to zero. Therefore, even if the current operating pressure of the cylinder assembly 400 is higher than the maximum rated pressure of the internal cylinder 305 when used alone (e.g., corresponding to full-pressure operation, where the external cylinder 405 defines the rated pressure of the cylinder assembly 400), damage to the internal cylinder 305 is prevented. However, when the piston 205 is in a second position separated from the end stop 435 (e.g., at the opposite end of the stroke, such as...), Figure 5 As shown), the pressure in the gap 325 may be different from that in the second internal volume 350A on the second side 324 of the piston 205 inside the internal cylinder 305 (for example, there may be a pressure difference across the wall of the internal cylinder 305 between the two volumes).

[0040] Therefore, to prevent damage to the internal cylinder 305 (e.g., due to a pressure differential exceeding the rated differential pressure), a pressure relief valve 415 may be fixed to a port 412 in fluid communication with the central channel 360 (e.g., extending through the cover 410, as shown). In some examples, the pressure relief valve 415 may be positioned within a sealed cavity 420 removably mounted to the cover 410. In some examples, the sealed cavity 420 may be in fluid communication with the gap 325 via an opening 430 extending through the cover 410, so that the gas pressure within the internal volume 425 of the cavity 420 may be approximately equal to the gas pressure within the gap 325. Therefore, when the pressure differential between the internal volume of the internal cylinder 305 (e.g., the second internal volume 350A) and the gap 325 exceeds a predetermined value (e.g., approximately 150 PSI), the pressure relief valve 415 may open and discharge gas from the top side of the internal cylinder 305 into the internal volume 425. In this way, for example, the pressure relief valve 415 prevents damage to the internal cylinder 305.

[0041] In some examples, piston 205 may become stuck between the first and second positions, which could prevent piston contact end stop 435 from moving. To reduce the risk of damage to the internal cylinder 305 in this situation, a second pressure relief valve (see example...) can be provided. Figure 9 For example, the second pressure relief valve may be in fluid communication with the circumferential passage 335 such that when the pressure difference between the gap 325 and the internal volume of the internal cylinder 305 (e.g., the second internal volume 350A) exceeds a predetermined value (e.g., about 150 PSI), the second pressure relief valve may open to release pressure from the gap (and the lower side of piston 205) to the internal volume on the upper side of piston 205.

[0042] Figure 6 and Figure 7An example of an instrument mounting system 600 for use with cylinder 705 (or cylinders 300, 400) is shown. In some examples, the instrument mounting system 600 may be an integral component (i.e., connected together to be assembled / removed as a single piece, and jointly supported relative to the corresponding cylinder). For example, system 600 may be an integral component including a cover 605 and one or more instruments 610, which are mounted to the cover 605 to be jointly supported relative to the corresponding cylinder by the cover 605. In some examples, the cover 605 provides a relatively large, rigid, flat surface area for direct mounting of the instrument 610, allowing it direct access to both sides of piston 205 without external lines or pipes. For example, the instrument 610 may be mounted to the cover 605 using one or more instrument ports 710, which provides a flow path for instrument gases from the internal volume of cylinder 705 to the instrument and from the instrument to the internal volume of cylinder 705. In some examples, instrument 610 may be in the form of one or more flow amplifiers (e.g., a first flow amplifier 615 and a second flow amplifier 620), a pneumatic controller, or other known control instruments (e.g., a one-way flow amplifier, a solenoid valve, a trip valve, a regulator, etc.).

[0043] In some examples, the instrument mounting system 600 can be removably mounted on the cylinder 705 via one or more fasteners (such as screws, bolts, tie rods, or other known fasteners), allowing the user to remove / replace the instrument mounting system 600 (e.g., as an integral component). Therefore, the instrument mounting system 600 can be removed and replaced for maintenance, changing the instrument type, or retrofitting applications by simply removing the fasteners, removing the first cover from the cylinder, placing the second cover on the cylinder, and securing the cover by replacing the fasteners.

[0044] Figure 8 and Figure 9 The diagram shows the available Figure 1 Another example of the instrument mounting system 800 used for the control valve cylinder (e.g., as an alternative configuration to instrument mounting system 600). As will be appreciated, instrument mounting system 800 shares many of the same components with the previously illustrated and described examples and operates in a similar manner. For the sake of brevity, these common features will not be described in detail below. Rather, unless otherwise indicated, the previous discussion of features with common names or numbers applies equally to the example configuration of instrument mounting system 800.

[0045] In some examples, the instrument mounting system 800 can be used with the previously described cylinders 300, 400. For example, the instrument mounting system 800 may include a pair of sealed cavities 805, 810 (e.g., for a pressure relief valve or other instrument) fixed to a cover 605 of the instrument mounting system 800. Furthermore, the instrument mounting system 800 may include a series of instruments 820 that can be fixed to the sealed cavities 805, 810. Thus, the instruments 820 may be fixed to the cover 605 via the pressure relief valve cavities 805, 810. For applications that do not include a pressure relief valve, the instruments 820 may be mounted directly to the cover 605 (e.g., via one or more instrument ports 710).

[0046] In some examples, the instrument 820 may be in the form of one or more flow amplifiers 825. In a particular example, in applications requiring high travel speeds, it is advantageous to use multiple dead-zone flow amplifiers 825 to achieve the desired travel speed. Thus, two flow amplifiers may be connected in parallel to the upper cylinder (e.g., one side of piston 205), and two flow amplifiers may be connected in parallel to the lower cylinder (e.g., the opposite side of piston 205), which facilitates rapid movement in each direction. In another example, the instrument 820 may be in the form of a pneumatic controller, which may include a remote stroke sensor (e.g., mounted near yoke 140) and a base unit that may be mounted on cover 605.

[0047] As should be understood, the instrument 820 may require maintenance or even replacement during its service life. In this regard, a useful feature of the instrument mounting system 800 is that all instruments 820 can be directly secured to the cover 605 to form a single, integrated assembly. Therefore, all instruments 820 can also be removed / disconnected simply by removing the cover 605 (e.g., by removing fasteners), without dealing with complex piping connections or other issues. This configuration correspondingly eliminates the need to interfere with any fittings when modifying, replacing, or maintaining the instruments, and further eliminates the risk of accidentally reinstalling the instruments incorrectly.

[0048] Figure 10 The diagram shows the available Figure 1 Another example of the instrument mounting system 1000 used for the control valve cylinder (e.g., as an alternative configuration to instrument mounting system 800). As will be appreciated, instrument mounting system 1000 shares many of the same components with the previously illustrated and described examples and operates in a similar manner. For the sake of brevity, these common features will not be described in detail below. Rather, unless otherwise indicated, the previous discussion of features with common names or numbers applies equally to the example configuration of instrument mounting system 1000.

[0049] In some examples, when using instrument gas from the pipeline, the instrumentation system 1000 can be configured to re-inject the instrument gas into the downstream portion of the pipeline after use. Therefore, the control valve 100 can operate in a zero-emission state, meaning the valve functions without releasing gas (e.g., pipeline gas) into the atmosphere. As should be understood, this configuration helps prevent the loss of valuable materials (e.g., via gas loss) and avoids leakage events (e.g., involving the release of natural gas into the atmosphere) that could trigger reporting requirements or other regulatory consequences.

[0050] In the illustrated example, to achieve this zero-emission state, one or more instruments 1015 (e.g., positioners, pressure relief valves, relays, regulators, flow amplifiers, trip valves, etc.) for controlling the operation of valve 100 are housed within a pressurized chamber 1010. For example, to form the pressurized chamber 1010, the instrument mounting system 1000 may include a body 1005 and a removable cap 1030. In some examples, the body 1005 may be removably secured to a cylinder (e.g., any cylinder previously described) via one or more fasteners. Similarly, the cap 1030 may be removably secured to the body 1005 via one or more fasteners. Thus, a user can remove the cap 1030 to access the pressurized chamber 1010 (e.g., to replace, maintain, or remove one or more instruments 1015).

[0051] In some examples, because the chamber pressure is equal to (or greater than) the downstream pressure, any fluid consumed by instrument 1015 (e.g., initially drawn from the upstream portion of the line) can therefore be reinjected via outlet 1020 into the low-pressure portion (e.g., the downstream portion) of line 1025. For example, pressure regulator 1035 within chamber 1010 can automatically adjust based on downstream pressure (e.g., in the downstream portion of the line) and correspondingly adjust upstream pressure (e.g., in the upstream portion of the line) to maintain a desired differential pressure, which allows fluid used by the instrument to be reinjected into the downstream portion of the line. This configuration eliminates leakage to the atmosphere while still allowing the use of a variety of conventional instruments. For example, an instrument rated to operate based on a specific differential pressure relative to a standard environment (e.g., where the standard pressure is 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) differential pressure) in the elevated pressure environment provided by pressurized chamber 1010.

[0052] In other words, the conventional design and operation of pneumatic instruments used in process control industries are based on a static reference pressure equal to the local atmospheric pressure. These instruments can be integrated into control systems because each instrument shares a common reference pressure (e.g., local atmospheric pressure). This shared atmospheric reference pressure also ensures that the gas consumed by the instrument can be vented when needed. In contrast, chamber 1010 provides the pneumatic instruments with an alternative reference pressure that can be raised and has a dynamic nature. Therefore, for example, when the reference pressure (e.g., downstream line pressure, pressure within cylinders 305, 405, etc.) fluctuates, the pneumatic instrument pressure can “float” with the fluctuation of the reference pressure, thereby maintaining a sufficient differential pressure to operate the instrument and maintaining sufficient output pressure to re-inject the instrument gas into the line. This allows the instrument to provide precise and rapid-response control while still venting downstream, essentially eliminating the venting of gas into the atmosphere.

[0053] In some examples, the apparatus or system disclosed herein may be utilized, manufactured, or assembled using methods embodying aspects of the invention. Correspondingly, any description herein of a particular feature, function, or intended use of an apparatus or system is generally intended to include disclosures of: methods of using such an apparatus for its intended use, methods of otherwise implementing such function, methods of manufacturing related components (or the entire apparatus or system) of such an apparatus or system, and methods of assembling the disclosed (or otherwise known) components to support such use or function. Similarly, unless otherwise indicated or limited, any discussion herein of any method of manufacturing or using a particular apparatus or system (including assembling such an apparatus or system) is intended to inherently include the disclosures of the features utilized and functions implemented by such apparatus or system (as embodiments of the invention). In this regard, for example, examples of the disclosed technology may include improved actuators and actuator components, correspondingly improved valves and valve assemblies, and methods of manufacturing, assembling (e.g., modifying), and disassembling such instruments.

[0054] Furthermore, as used herein, unless otherwise limited or specified, "or" signifies a non-exclusive set of components or operations that can exist in various arbitrary combinations, rather than an exclusive set of components that can only exist in a mutually substitutable manner. For example, a set of "A, B, or C" signifies the following options: A; B; C; A and B; A and C; B and C; and A, B, and C. Correspondingly, the term "or" as used herein is intended to signify exclusive substitution only when preceded by an exclusive term (such as "any," "one of," "only one of," or "exactly one of"). For example, a set of "one of A, B, or C" signifies the following options: A, but without B and C; B, but without A and C; and C, but without A and B. A set preceded by "one or more" (and its variations) and including an "or" to separate the listed elements signifies an option: 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's; one or more B's; one or more C's; one or more A's and one or more B's; one or more B's and one or more C's; one or more A's and one or more C's; and one or more A's, one or more B's, and one or more C's. Similarly, a group preceded by "multiple" (and its variations) and including an "or" to separate the listed elements indicates an option: multiple examples of any or all of the listed elements. For example, the phrases "multiple 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.

[0055] As used herein, unless otherwise specified or limited, directional terms are used for convenience of reference when discussing a particular figure or example. For example, references to a downward direction (or other direction) or a top position (or other position) may be used to discuss aspects of a particular example or figure, but it is not required that all devices or configurations be in similar orientations or geometries.

[0056] Furthermore, as used herein, unless otherwise limited or specified, “substantially parallel” means a direction that deviates from the reference direction within ±12 degrees (e.g., within ±6 degrees), including end values.

[0057] Furthermore, as used herein, unless otherwise limited or specified, “substantially perpendicular” means a direction that deviates from the reference direction by within ±12 degrees (e.g., within ±6 degrees), including end values.

[0058] Furthermore, as used herein, unless otherwise limited or specified, "integral" and its derivatives (e.g., "integrally") describe an element manufactured as a single piece without the need for fasteners, adhesives, or the like to hold separate parts together. For example, the following elements are integral (and integrally formed) elements, meaning they are formed as single-piece components by stamping, casting, or otherwise shaping, using a single sheet of metal or a single mold, without the need for rivets, screws, or adhesives to hold the separately formed parts together. In contrast, an element formed from multiple parts initially formed separately and later joined together is not an integral (or integrally formed) element.

[0059] Furthermore, unless otherwise specified or limited, the terms “about” and “approximately” used herein with respect to reference values ​​refer to a change 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 reference values ​​refer to a change of less than ±30% from the reference value (including the endpoints). When explicitly specified, “substantially” may specifically indicate a change in a numerical direction relative to the reference value. For example, “substantially lower” than the reference value (and similar expressions) indicates a value that is 30% or more lower than the reference value, and “substantially higher” than the reference value (and similar expressions) indicates a value that is 30% or more higher than the reference value.

[0060] Furthermore, as used herein, unless otherwise limited or specified, “substantially identical” means two or more parts or systems manufactured or used according to the same processes and specifications, wherein variations between the parts or systems are within acceptable tolerances of the relevant processes and specifications. For example, two parts may be considered substantially identical if they are manufactured using the same materials according to the same standardized manufacturing steps and are within the same acceptable dimensional tolerances (e.g., specified for a particular process or product).

[0061] Unless otherwise specifically indicated, sequential numbering is used herein for ease of reference and is generally based on the order in which specific components are presented in the relevant sections of this disclosure. In this regard, for example, designations such as “first” and “second” generally only indicate the order in which such labeled components are introduced into discussion and generally do not indicate or require a particular spatial, functional, temporal, or structural priority or order. Relatedly, similar or identical components may be referred to using different sequential numbering in different contexts.

[0062] The above description of the disclosed embodiments is provided to enable those skilled in the art to make or use the invention. Based on the benefits of this disclosure, various modifications to these embodiments will be apparent to those skilled in the art, and the principles defined herein can be applied to other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not intended to be limited to the embodiments shown herein, but should be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An actuator for a fluid control device, the actuator comprising: Cylinder assembly, comprising: Internal cylinder; An outer cylinder circumferentially surrounds the inner cylinder to form a radial gap therebetween; A first end cap is fixed to the first end of the cylinder assembly to close the first end of the inner cylinder and the first end of the outer cylinder; A second end cap, which is fixed to a second end of the cylinder assembly opposite to the first end of the cylinder assembly, to close the second end of the inner cylinder and the second end of the outer cylinder; and A piston, which is arranged within the internal cylinder, is capable of translating within the internal cylinder in response to a pressure difference across the piston, thereby actuating the fluid control device.

2. The actuator of claim 1, wherein the inner cylinder is made of a first material and the outer cylinder is made of a different second material.

3. The actuator of claim 2, wherein the first material of the inner cylinder comprises a composite material, and the second material of the outer cylinder comprises a metallic material.

4. The actuator according to claim 1, further comprising: A cover, which is removably mounted to the second end of the cylinder assembly to seal the internal volume of the cylinder assembly; A pressure relief valve is in fluid communication with the internal volume of the internal cylinder via a port extending through the cover.

5. The actuator of claim 1, wherein the first end of the internal cylinder includes one or more first openings, the one or more first openings providing fluid communication from the radial clearance to an internal volume of the internal cylinder on a first side of the piston for translating the piston in a first direction.

6. The actuator of claim 5, wherein the second end cap includes one or more second openings that provide fluid communication through the second end cap to the radial gap to guide a gas drive flow into the radial gap.

7. The actuator of claim 6, wherein the second end cap further comprises one or more third openings to direct the drive flow into an internal volume of the internal cylinder on the second side of the piston, thereby translating the piston in a second direction.

8. The actuator of claim 7, wherein the one or more second openings comprise a plurality of second openings arranged circumferentially around the second end cap, and the one or more third openings comprise a central opening.

9. The actuator of claim 1, wherein the rated pressure of the internal cylinder is set to the maximum pressure differential for translating the piston, and the rated pressure of the external cylinder is correspondingly set to the maximum rated pressure of the cylinder assembly.

10. The actuator according to claim 1, wherein when the piston contacts the end stop, the pressure of the driving fluid in the gap is approximately equal to the pressure of the driving fluid in the internal volume of the internal cylinder.

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