Volume booster with variable asymmetry

A volume booster for a fluid flow control device comprises a supply path for supplying a fluid boost to facilitate actuation of an actuator in a first direction, and an exhaust path for enabling controlled exhaust to facilitate actuation of the actuator in a second direction. The supply path defines a supply resistance that is set by the geometry of a supply trim component. The exhaust path includes an exhaust resistance that is set by the geometry of an exhaust trim component. The supply and exhaust trim components are independently removable and replaceable with replacement components to customize the exhaust and supply resistances, and therefore, the exhaust and supply capacities for specific applications.

FIELD OF THE DISCLOSURE

present disclosure relates to fluid flow control systems, and more particularly, to volume flow boosters for enhancing control valve performance in fluid flow control systems.

BACKGROUND

Systems for controlling the flow of fluids, such as compressed air, natural gas, oil, propane, or the like, are generally known in the art. These systems often include at least one control valve for controlling various flow parameters of the fluid. Typical control valves include a control element such as a valve plug, for example, movably disposed within the flow path for controlling the flow of the fluid. The position of such a control element can be controlled by a positioner via a pneumatic actuator such as a piston actuator or a diaphragm-based actuator, as is known in the art. Conventional positioners deliver pneumatic signals to the actuator to stroke the control element of the control valve between an open and closed position, for example. The speed at which a standard positioner can stroke the control valve, however, partly depends on the sizes of the actuator and the control valve. For example, larger actuators/control valves typically take longer to be stroked.

Therefore, such systems additionally employ one or more volume boosters located between the positioner and the actuator. The volume boosters are used to amplify the volume of the pneumatic signal sent from the positioner, thereby increasing the speed at which the actuator strokes the control element of the control valve. Conventional volume boosters are offered in varying capacities such that a specific volume booster can be installed into a control system to suit a specific application. If the application changes, the volume booster can be switched out for a different volume booster having a different capacity.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The examples, i.e., embodiments, described herein are not intended to be exhaustive or to limit the scope of the invention to the precise form or forms disclosed. Rather, the following description has been chosen to provide examples of the one or more preferred embodiments to those having ordinary skill in the art.

FIG. 1provides a schematic representation of a single-acting spring and diaphragm actuator assembly10constructed in accordance with the principles of the present disclosure. Specifically, the actuator assembly10comprises an actuator12, a positioner14, and a volume booster16. In the disclosed embodiment, the actuator assembly10is also illustrated as being fluidly coupled to a regulator18. The actuator12is adapted to be operably connected to a control valve (not shown) equipped with a movable control element for controlling the flow of a fluid through a system such as a fluid distribution or other fluid management system, for example.

Still referring toFIG. 1, the volume booster16includes an inlet port30, a common port32, a control port34, and a discharge port36. The positioner14includes an inlet38and an outlet40. The actuator12includes a booster communication port42. The actuator12, the positioner14, the volume booster16, and the regulator18communicate with each other via a plurality of fluid lines. Specifically, the regulator18is in fluid communication with the positioner14and the volume booster16via a supply line L1, which is split into a first supply line L1′ and a second supply line L1″. The outlet40of the positioner14is in fluid communication with the control port34of the volume booster16via an output signal line L2. The common port32of the volume booster16is in fluid communication with the booster communication port42of the actuator12via a control line L3.

As will be described in more detail, the first supply line L1′ is adapted to deliver a supply pressure to the inlet38of the positioner14and the second supply line L1″ is adapted to deliver a supply pressure to the inlet port30of the volume booster16. The supply pressure can be provided to the supply line L1via the regulator18from a pressure source such as a compressor, for example. Additionally, the positioner14is adapted to deliver a pneumatic control signal to the volume booster16via the output signal line L2for controlling the operation of the actuator12.

For example, based on an electrical signal received from a controller20via an electrical connection E1, the positioner14transmits a pneumatic signal to the control port34of the volume booster16via the output signal line L2. The pneumatic signal passes through the volume booster16to instruct the actuator12to actuate the control valve (not shown). Typically, the positioner14is adapted to generate a pneumatic signal of a relatively modest pressure. Therefore, depending on the size of the actuator12and/or the desired speed at which the actuator12is to stroke the control valve, the volume booster16can operate to supplement the pneumatic signal with additional fluid sourced from the supply line L1, as will be described.

In the embodiment depicted inFIG. 1, the actuator12includes a fail-up actuator comprising a diaphragm22and a spring24contained within a diaphragm casing26. The diaphragm22divides the casing26into a top cavity26aand a bottom cavity26b. The spring24is disposed in the bottom cavity26bof the casing26and biases the diaphragm22upward. Therefore, when the positioner14sends a pneumatic signal to the volume booster16via the output signal line L2, pneumatic pressure is introduced into the top cavity26aof the actuator12, thereby moving the diaphragm22downward. This downward movement is then transferred into a corresponding movement of the control element of the associated control valve (not shown), as is understood within the art.

Preferably, the casing26includes one or more vents28such that fluid contained within the bottom cavity26bvents out of the casing26when the diaphragm22moves downward. Such venting facilitates the movement of the diaphragm22in the downward direction. To stroke the actuator12upward, the positioner14stops sending the pneumatic signal to the volume booster16such that the spring24moves the diaphragm22upward. As the diaphragm22moves upward, the pressure built up in the upper cavity26aof the casing26exhausts to the atmosphere via the control line L3and the discharge port36of the volume booster16. This exhausting to the atmosphere facilitates the movement of the diaphragm22in the upward direction.

With reference now toFIG. 2, one embodiment of the volume booster16depicted inFIG. 1will be described. In general, the volume booster16includes a body44, a trim assembly46, a control element48, a diaphragm assembly50, and a bypass adjustment device52.

The body44generally includes a trunk portion54, a cap portion56, and a bushing portion58. The trunk portion54of the body44defines the inlet port30and the common port32. Additionally, the trunk portion54defines a supply trim opening60, an inlet chamber62, a common chamber64, a throat region66, an exhaust chamber68, and a bypass passage69. The throat region66is disposed between the inlet chamber62and the common chamber64and generally defines a cylindrical cavity including a lower web70and an upper web72. The lower and upper webs70,72each include threaded cylindrical openings receiving portions of the trim assembly46, as will be described. Similarly, the supply trim opening60includes a threaded cylindrical opening receiving a portion of the trim assembly46.

The trim assembly46includes a supply trim component74and an exhaust trim component76. The supply trim component74includes a cylindrical bushing removably threaded into the supply trim opening60of the trunk portion54of the body44of the volume booster16. More specifically, the supply trim component74includes a skirt portion80, a hexagonal nut portion82, and a spring seat84.

The skirt portion80includes a generally hollow cylindrical member extending from the hexagonal nut portion82into the supply chamber62of the trunk portion54of the body44. The skirt portion80defines a plurality of passages86extending radially therethrough. In the depicted embodiment, the passages86include cylindrical bores. Thus, the passages86extend along an axis that is generally perpendicular to an axis of the skirt portion80. So configured, the skirt portion80of the supply trim component74restricts the flow of fluid through the body44from the supply chamber62to the throat region66.

Still referring toFIG. 2, the exhaust trim component76includes a cylindrical bushing removably threaded into the cylindrical opening of the upper web72of the throat region66of the body44. More specifically, the exhaust trim component76includes a hexagonal nut portion88, a restrictor portion90, a skirt portion92, and a seating portion94.

The hexagonal nut portion88of the exhaust trim component76is disposed within the exhaust chamber68of the body44and abutted against the upper web72. The restrictor portion90includes a generally solid cylindrical member disposed within the cylindrical opening of the upper web72and defines a plurality of exhaust passages96and a control opening97. In the depicted embodiment, the passages96in the restrictor portion90include cylindrical bores extending axially through the exhaust trim component76. The skirt portion92extends from the restrictor portion90into the throat region66and defines a plurality of windows98. So configured, the plurality of passages96in the restrictor portion90provides constant fluid communication between the common chamber64and the exhaust chamber68, via the windows98in the skirt portion92.

The seating portion94of the exhaust trim component76includes a generally cylindrical member disposed within a cylindrical opening of the lower web70of the body44. The seating portion94defines a central bore100and a valve seat102. The central bore100is defined herein as a “supply port” of the volume booster16. In the disclosed embodiment, the seating portion94also includes an external annular recess104receiving a seal106such as an o-ring. The seal106provides a fluid tight seal between the seating portion94of the exhaust trim component76and the lower web70.

As illustrated inFIG. 2, the control element48of the disclosed embodiment of the volume booster16includes a dumbbell shaped control element comprising a supply plug108, an exhaust plug110, and a stem112. The stem112extends between and connects the supply plug108to the exhaust plug110, and is slidably disposed in the control opening97of the restrictor portion90of the exhaust trim component76. So configured, the exhaust plug110is disposed within the exhaust chamber68of the body44, and the supply plug108is disposed within the supply chamber62of the body44. More specifically, the supply plug108is disposed inside of the skirt portion80of the supply trim component74and is biased away from the supply trim component74by a spring114. The spring114is seated against the spring seat84of the supply trim component74. The spring114biases the supply plug108of the control element48into engagement with the valve seat102of the seating portion94of the exhaust trim component76, thereby closing the “supply port”100. In the disclosed embodiment, each of the supply and exhaust plugs108,110includes a tapered cylindrical body defining a frustoconical seating surface. Other shapes of course could be implemented to satisfy the intended functions.

As mentioned above, the bushing portion58of the body44of the volume booster16is sandwiched between the cap portion56and the trunk portion54. Generally, the bushing portion58includes an annular ring defining a radial through-bore, which comprises the discharge port36of the volume booster16. Additionally, the bushing portion58defines an axial through-bore116in alignment with the bypass passage69of the trunk portion54of the body44. The discharge port36provides fluid communication between the exhaust chamber68of the trunk portion54of the body44and the atmosphere, via the diaphragm assembly50, as will be described.

The diaphragm assembly50comprises a floating manifold120sandwiched between first and second diaphragms122,124. The first diaphragm122includes a flexible diaphragm made from a known diaphragm material and includes a peripheral portion122aand a central portion122b. The peripheral portion122ais compressed between the cap portion56and the bushing portion58of the body44of the volume booster16. The peripheral portion122aadditionally defines an opening126in alignment with the axial through-bore116of the bushing portion58. The second diaphragm124similarly includes a flexible diaphragm made from a known diaphragm material and includes a peripheral portion124aand a central portion124b. The peripheral portion124aof the second diaphragm124is compressed between the bushing portion58and the trunk portion54of the body44. The peripheral portion124aadditionally defines an opening129in alignment with the axial through-bore116of the bushing portion58. The central portion124bfurther defines a central opening131. The manifold120is disposed between the central portions122b,124bof the first and second diaphragms122,124such that an annular passage127is defined between the manifold120and the bushing portion58of the body44.

The manifold120comprises a disc-shaped member movably disposed inside of the bushing portion58of body44. The manifold120defines an axial opening128, an internal cavity130, and a plurality of radial passages132. The axial opening128is aligned with the central opening131in the second diaphragm124and is defined herein as an “exhaust port” of the volume booster16. The axial opening128is equipped with a seating member135defining a valve seat137. The axial opening128provides for fluid communication between the exhaust chamber68of the trunk portion54of the body44and the internal cavity130of the manifold120. The radial passages132provide for fluid communication between the internal cavity130of the manifold120and the annular passage127disposed between the manifold120and the bushing portion158of the body44.

As is also depicted inFIG. 2, the present embodiment of the volume booster16includes a seating cup134and a spring136disposed between the diaphragm assembly50and the cap portion56of the body44. The seating cup134receives the spring136and the spring136biases the diaphragm assembly50away from the cap portion56such that the valve seat137of the seating member135disposed in the axial opening128of the manifold120engages the exhaust plug110of the control element46. This engagement closes the “exhaust port”128.

Finally, the cap portion56of the body44of the volume booster16includes the control port34and a threaded bore138connected by a fluid passage140. Additionally, the cap portion56defines a signal chamber142disposed above the diaphragm assembly50and in fluid communication with the control port34. The threaded bore138accommodates the bypass control device52, which in one embodiment can include an adjustment screw. The bypass control device52can therefore be adjusted to adjust the volume of fluid that is allowed to travel from the control port34to the common chamber64, as will be described.

As described above, to actuate the actuator12in the downward direction, the positioner14sends a pneumatic signal to the volume booster16. Depending on the magnitude of the pressure of the pneumatic signal, the signal either actuates the actuator12by itself, or the signal activates the volume booster16and the signal is supplemented by fluid pressure supplied from the regulator18.

For example, if the pressurized signal is not high enough to activate the volume booster16, as will be described, the fluid travels from the control port34, through the fluid passage140in the cap portion56, beyond the bypass adjustment device52, and to the common chamber64of the trunk portion54of the body44, via the axial through-bore116in the bushing portion58, and the bypass passage69in the trunk portion54of the body44. From there, the fluid exits the body44, via the common port32, and enters the booster communication port42of the actuator12to move the diaphragm22in the downward direction.

While the pressurized signal actuates the actuator12, it is also provided to the signal chamber142defined by the cap portion56of the body44. Additionally, a steady supply pressure is constantly provided to the supply chamber62of the trunk portion54of the body44from the regulator18(shown inFIG. 1).

For the sake of description, a pressure differential across the volume booster16is defined as a pressure differential occurring across the diaphragm assembly50, i.e., between the signal chamber142and the exhaust chamber68. Because the exhaust chamber68is in continuous fluid communication with the output chamber64of the trunk portion54of the body44(via the exhaust passages96in the exhaust trim component76), it can also be said that a pressure differential across the volume booster16is defined as a pressure differential occurring between the signal chamber142and the output chamber64.

If the pressure differential across the volume booster16is insubstantial, the supply and exhaust plugs108,110of the control element48remain in the closed positions, as depicted inFIG. 2, whereby each sealingly engages the valve seats102,137of the respective supply and exhaust ports100,128. So disposed, the diaphragm assembly50stays in a static unloaded position. This position is also assisted by the spring114biasing the supply plug108into engagement with the supply port100, and the spring136biasing the diaphragm assembly50into engagement with the exhaust plug110.

In contrast, a substantial pressure differential across the volume booster16is one that is great enough to affect the diaphragm assembly50, whether up or down, to move the control element48, relative to the orientation of the volume booster16depicted inFIG. 2.

During operation, a positive differential condition is achieved when pressure is substantially greater in the signal chamber142than in the exhaust chamber68such as when the positioner14delivers a high pressure signal to the control port34. This can occur when the controller20instructs the positioner14to stroke the actuator12in the downward direction, for example. The high pressure signal forces the floating diaphragm assembly50downward, which moves the control element48downward, thereby keeping the exhaust plug110closed against the exhaust port128and moving the supply plug108away from the supply port100. Thus, the volume booster16opens a “supply path,” which provides fluid flow from the regulator18to the actuator12via the volume booster16. Specifically, fluid from the regulator18flows into the supply chamber62, then through the supply port100and the common chamber64to the actuator12, via the common port32. Again, because the common chamber64is also in constant fluid communication with the exhaust chamber68via the exhaust passages96in the exhaust trim component76, the pressure in the common camber64is also registered on the second diaphragm124of the diaphragm assembly50.

When the controller20instructs the positioner14to stroke the actuator12back upward, the positioner14may reduce the pressure of the pneumatic signal transmitted to the volume booster16. This causes the pressure in the signal chamber142to reduce and equalize with the pressure in the common chamber64. The diaphragm assembly50begins to rise back upward, and the spring114biases the control element48back upward such that the supply plug108reseals against the valve seat102of the supply port100, thereby closing the “supply path.”

Once the “supply path” is closed, the control element48cannot move further upward, but back pressure from the common chamber64moves the diaphragm assembly50further upward against the force of the spring136. This moves the diaphragm assembly50away from the exhaust plug110of the control element48and opens the exhaust port128. With the exhaust port128open, the volume booster16defines an “exhaust path” between the common chamber64and the discharge port36. That is, pressurized fluid in the common chamber64travels to the exhaust chamber68via the passages96in the exhaust trim component76, then to the central cavity130of the manifold120via the central opening128, through the radial passages132in the manifold120, and out of the exhaust port36to the atmosphere.

As mentioned above, the bypass adjustment device52can be adjusted so that different pressures from the positioner14will activate the volume booster16, as just described. For example, if the bypass adjustment device52nearly completely blocks communication between the control port34and the bypass passage69to the common chamber64, a relatively small pressure from the positioner14can activate the volume booster16. This is because nearly all of the pressure transmitted by the positioner14will enter the signal chamber142and bear on the first diaphragm122, thereby forcing the diaphragm assembly50and the control element48downward to open the “supply path” by opening the supply port100. In contrast, if the bypass adjustment device52allows a large volume of fluid to flow through to the bypass passage69and onto the control chamber64, less fluid pressure will bear on the first diaphragm122of the diaphragm assembly50, and the volume booster16will only be activated under a comparatively higher pressure from the positioner14.

Volume boosters of this type can generally be characterized as having an exhaust capacity and a supply capacity. The exhaust capacity can be described as the maximum volume of fluid capable of traveling along the “exhaust path,” i.e., from the common chamber64to the discharge port36when the exhaust port128is open. The exhaust capacity of the volume booster16depicted inFIG. 2is, at least partly, dependent on the geometry and dimensions of the “exhaust path” such as the exhaust passages96in the exhaust trim component76. That is, the exhaust trim component76operates as a restriction to the flow of fluid along the “exhaust path.”

For example, the supply passages86define a fluid flow resistance for the supply trim component74, which directly affects the capacity of the “supply path,” i.e., the supply capacity. The fluid flow resistance is a function of the geometry of the skirt portion80, including a diameter Ds, a longitudinal dimension Ls, and the number of passages86. The longitudinal dimension Lsis equal to, and therefore, dependent on a radial dimension of the skirt portion80, while the diameter Dscan be arbitrarily selected or carefully calculated and selected based upon desired flow characteristics of the volume booster16.

The supply capacity can be described as the maximum volume of fluid capable of traveling along the “supply path,” i.e., from the supply chamber62to the common chamber64when the supply port100is open. The supply capacity of the volume booster16depicted inFIG. 2is, at least partly, dependent on the geometry and dimensions of the supply passages86in the supply trim component74. That is, the supply trim component74operates as a restriction to the flow of fluid along the “supply path.”

For example, the exhaust passages96define a fluid flow resistance for the exhaust trim component79, which directly effects the capacity of the “exhaust path,” i.e., the exhaust capacity. The fluid flow resistance is a function of the geometry of the exhaust trim component76, including a diameter De, a longitudinal dimension Le, and the number of exhaust passages96. The longitudinal dimension Leis equal to, and therefore, dependent on an axial dimension of the exhaust trim component76, while the diameter Decan be arbitrarily selected or carefully calculated and selected based upon desired flow characteristics of the volume booster16.

Optimum operational conditions allow for the actuator12depicted inFIG. 1to be actuated in either direction in generally the same amount of time, which is referred to as symmetric performance. To enable symmetric performance, the supply capacity and the exhaust capacity of the volume booster16depicted inFIG. 2should be substantially identical. So configured, fluid can flow along the “supply path” in generally the same capacity as it can flow along the “exhaust path.” Depending on a variety of system factors, the geometry of the volume booster16can affect whether or not symmetric performance is achievable.

Therefore, the presently disclosed volume booster16includes supply and exhaust trim components74,76that are removably secured within the body44. This advantageously enables the supply and exhaust capacities to be tailored for certain operational conditions.

For example, the hexagonal nut portion82of the supply trim component74enables a technician to grasp the supply trim component74with a wrench, for example, to install the supply trim component74into the body44, as well as remove the supply trim component74from the body44such that it can be replaced with an alternative supply trim component. Replacement supply trim components can have differently configured skirt portions, thereby defining different fluid flow resistances and supply capacities. For example, replacement supply trim components can include skirt portions defining passages with varying diameters. Passages with smaller diameters, will generate greater fluid flow resistance than passages with larger diameters. Additionally, replacement supply trim components can include skirt portions of varying thickness, thereby defining passages of varying longitudinal dimensions. Passages with smaller longitudinal dimensions will generate less fluid flow resistance than passages with greater longitudinal dimensions. Furthermore, replacement supply trim components can include skirt portions defining passages that are shaped and configured other than to include cylindrical bores to define different fluid flow resistances. Further still, replacement supply trim74components can have a different number of passages86to alter the flow resistance.

Similar to the supply trim component74, the exhaust trim component76can be removed from the body44and replaced with an alternative exhaust trim component having a different exhaust capacity. The exhaust trim component76can be removed from the body44by first removing the cap portion56, the bushing portion58, and the diaphragm assembly50. Then, a tool such as a wrench, for example, can be used to grasp the hexagonal nut portion88of the exhaust trim component76to remove the exhaust trim component76from the body44. Replacement exhaust trim components76can have exhaust passages96of different diameters, different longitudinal dimensions, more or fewer passages96, or passages86having distinct shapes and configurations for generating generally any desired exhaust capacity.

FIG. 3depicts an alternative volume booster216constructed in accordance with the principles of the present disclosure. For example, the volume booster16depicted inFIG. 1comprises a globe-style body44, while the volume booster216depicted inFIG. 3comprises an angled-style body244. The angled-style body244provides different packaging that can minimize excess external piping in certain system applications. The body244nevertheless comprises a trunk portion254, a cap portion256, and a bushing portion258. The body244further includes an inlet coupler260. The cap portion256and bushing portion258are identical to the cap portion56and the bushing portion58described above with reference to the volume booster16depicted inFIG. 2, and therefore, the details thereof will not be repeated.

The trunk portion254of the body244includes a common port232, a common chamber264, a throat portion266, and an exhaust chamber268. The throat portion266defines a lower web270, an upper web272, a throat chamber267, and an inlet opening269. The inlet coupler260of the body244defines an inlet port230and an inlet chamber262. The inlet coupler260is threadably attached to the throat portion266of the trunk portion254of the body244such that the inlet port230is disposed approximately 90° relative to the common port232.

Still referring toFIG. 3, the volume booster216includes a trim assembly246, a control element248, a diaphragm assembly250, and a bypass control device252. Generally, the control element248, the diaphragm assembly250, and bypass control device252are identical to the corresponding components described above with reference to the volume booster16depicted inFIG. 2, and therefore, the details thereof will not be repeated.

The trim assembly246of the volume booster216includes a supply trim component274and an exhaust trim component276. The supply trim component274comprises a bushing with a radial flange275clamped between the inlet component260of the body244and the inlet opening269of the throat portion266of the body244. The supply trim component274defines a plurality of supply passages286and a spring seat284. The spring seat284supports a spring214that biases the control element248in the upward direction, relative to the orientation of the volume booster216depicted inFIG. 3. The supply passages286extend through the supply trim component274to provide for fluid communication between the inlet port230and the throat chamber267.

The exhaust trim component276includes a cylindrical bushing removably threaded into the cylindrical opening of the upper web272of the throat region266of the body244. More specifically, the exhaust trim component76includes a hexagonal nut portion288, a restrictor portion290, a skirt portion292, and a seating portion294.

The hexagonal nut portion288of the exhaust trim component276is abutted against the upper web272of the throat portion266such that restrictor portion290is disposed within the cylindrical opening of the upper web272. The restrictor portion290is a generally cylindrical member defining a plurality of exhaust passages296and a control opening297. In the depicted embodiment, the exhaust passages296in the restrictor portion290include cylindrical bores extending axially through the exhaust trim component276. The skirt portion292extends from the restrictor portion290into the throat region266and defines a plurality of windows298. So configured, the plurality of exhaust passages296in the restrictor portion290provide constant fluid communication between the common chamber264and the exhaust chamber268, via the windows298in the skirt portion292.

The seating portion294of the exhaust trim component276includes a generally cylindrical member disposed within a cylindrical opening of the lower web270of the body244. The seating portion294defines a central bore300and a valve seat302. The central bore300is defined herein as a “supply port” of the volume booster216. In the disclosed embodiment, the seating portion294also includes an external annular recess404receiving a seal306such as an o-ring. The seal306provides a fluid tight seal between the seating portion294of the exhaust trim component276and the lower web270of the body244.

During operation, the volume booster216described with reference toFIG. 3functions in a manner that is identical to the volume booster16described above with reference toFIG. 2. Therefore, the specific details will not be repeated.

Additionally, similar to the volume booster16described above, the supply and exhaust trim components274,276of the volume booster216depicted inFIG. 3can be removed and replaced with replacement supply and exhaust trim components to change the exhaust and supply capacities of the volume booster216to meet desired capacities for specific applications. To replace the supply trim component274, the inlet component260of the body244is threaded out of attachment with the inlet opening269of the trunk portion254of the body244. The supply trim component274can then be removed and replaced with a different supply trim component274having a different set of supply passages284defining a different fluid flow restriction and capacity. Then, the inlet component260can be re-threaded to the inlet opening269to secure the supply trim component274in place. To replace the exhaust trim component276, the cap portion256and bushing portion258of the body244, as well as the diaphragm assembly250, must first be removed from the trunk portion254of the body244. Then, a technician can grasp the hexagonal nut portion288of the exhaust trim component276with a wrench or other tool and remove the exhaust trim component276. A replacement exhaust trim component276, having a different set of passages defining a different exhaust fluid flow restriction and capacity, can be dropped into the trunk portion254of the body244, and threaded into the opening in the upper web272.

Accordingly, it should be appreciated that the volume boosters16,216described herein advantageously enable the supply and/or exhaust trim components to be removed and replaced with alternative trim components to change the exhaust and supply capacities of the volume boosters16,216to meet the needs of various applications. One advantage of the arrangement of the volume booster16described above with reference toFIG. 2is that it is more cost effective to service, for example, because once the body44is piped into the actuator assembly10, the supply and/or exhaust trim components74,76can be replaced with the same or alternative components without having to decouple the entire volume booster16from the system. Similarly, when using the volume booster216depicted inFIG. 3, only the inlet coupler260would have to be decoupled from the supply line to replace the supply trim component274.

While the volume boosters16,216have thus far been described as being used in the single-acting diaphragm actuator assembly10depicted inFIG. 1, the volume boosters16,216can also be adapted for use in a double-acting piston actuator assembly400, as shown inFIG. 4.

The double-acting piston actuator assembly400comprises a piston-based actuator412, a positioner414, first and second volume boosters416a,416b, a regulator418, and a controller420. The various components are connected together via a plurality of fluid lines. For example, the regulator418provides a pressurized supply to the positioner414and the volume boosters416a,416bvia a supply line L1. Based on an electrical signal received from the controller420, the positioner414delivers a pneumatic signal to each of the volume boosters416a,416bvia first and second output signal lines L2′, L2″. Finally, the volume boosters416a,416bdeliver control pressure to the actuator412via two control lines L3′, L3″.

The actuator412includes a casing413containing a piston415. The piston415is movable within the casing413based on the pressures received from the volume boosters416a,416b. For example, when the first volume booster416aintroduces a pressure into the casing413that is larger than a pressure introduced by the second volume booster416b, the piston415moves downward. As the piston moves downward, fluid stored in the casing413below the piston415exhausts through the second volume booster416b. When the fluid exhausts through the volume booster416b, fluid flows along the “exhaust path” described above with reference to the volume booster16depicted inFIG. 2. The exhausting process is the same whether the volume booster16depicted inFIG. 2or the second volume booster116depicted inFIG. 3is used for the second volume booster416b.

Similarly, when the second volume booster416bintroduces a pressure into the casing413that is larger than a pressure introduced by the first volume booster416a, the piston415moves upward. Therefore, as the piston moves upward, fluid stored in the casing413above the piston415exhausts through the first volume booster416a. Fluid exhausts through the first volume booster416ain a manner identical to how it exhausts through the second volume booster416b. Again, the exhausting process is the same whether the volume booster16depicted inFIG. 2or the volume booster116depicted inFIG. 3is used for the first volume booster416a.

Such a double-acting actuator assembly400operates optimally when the supply capacity of the volume boosters416a,416bis slightly greater than the exhaust capacities, which also means that the exhaust resistances are slightly greater than the supply resistances. This is because the casing413of the actuator412is preferably maintained under a constant positive pressure, which keeps the piston415“stiff.” A “stiff” piston415optimizes the stability of the actuator12by protecting the piston415against influence from external factors such as feedback from the corresponding control valve. When the supply and exhaust capacities are set too close to each other, the pressure within the casing of the actuator412will slightly decay upon each stroke of the piston415. The reduced exhaust capacity therefore counteracts this decay.

Thus, in the case where each of the volume boosters416a,416binclude the volume booster16depicted inFIG. 2, specific supply and exhaust trim components74,76having specifically sized supply and exhaust passages86,96can be selected such that the exhaust capacities are smaller than the supply capacities. The same selection process can be performed if each of the volume boosters416a,416binclude the volume booster116depicted inFIG. 3.

Thus, it should further be appreciated that the volume boosters16,116described herein advantageously enable the same volume booster, whether it be the volume booster16depicted inFIG. 2or the volume booster116depicted inFIG. 3, to be used in single-acting actuator assemblies10(FIG. 1) or double-acting actuator assemblies400(FIG. 5) without sacrificing performance. The adjustment between the various applications is easily made by changing one or both of the supply and exhaust trim components to meet the desired performance characteristics. For example, as discussed above, the volume boosters16,116described herein can be equipped for optimal performance the single-acting actuator assembly10ofFIG. 1by selecting supply and exhaust trim components74,76having generally identical supply and exhaust capacities and fluid flow restrictions. To retrofit a volume booster16,116that is being used in the single-acting actuator assembly10to be used in the double-acting actuator assembly400depicted inFIG. 4, the exhaust trim component76,276merely has to be removed and replaced with a different exhaust trim component76,276having an exhaust capacity that is lower than the supply capacity of the supply trim component74. Alternatively, the supply trim component74,274could be replaced with a different supply trim component74,274having a supply capacity greater than the exhaust capacity of the exhaust trim component76,276.

Accordingly, it can be said that at least the supply and exhaust trim components74,274,76,276of a volume booster16,116used for a given application include trim components that are removably attached to the body and defining supply and exhaust passages having supply and exhaust fluid flow resistances, respectively, that can be pre-selected from a plurality of distinct supply and exhaust fluid flow resistances. Such a pre-selected fluid flow resistances customizes the volume booster for the desired specific application.

Because the fluid flow resistances of the trim components are at least partly dependent on the geometry and/or dimensions of the passages in the trim components, it can also be said that the supply and exhaust trim components74,274,76,276of a selected volume booster16,116for a given application include supply passages86,286and exhaust passages96,296, where each set of passages has a selected set of dimensional parameters, the selected set of dimensional parameters pre-selected from a plurality of sets of distinct dimensional parameters. For example, these dimensional parameters can include, but are not limited to, the diameters Ds, Deand longitudinal dimensions Ls, Leof the supply and exhaust passages74,274,76,276.

Finally, in accordance with the foregoing, a technician can advantageously customize the boosters16,116described herein for any given application by determining the desired exhaust and supply capacities for the application. Then, the technician can select a supply trim component74,274and an exhaust trim component76,276based on the desired capacities. With the appropriate components selected, the technician can removably install the components into the volume booster.

Therefore, the supply and exhaust capacities of the volume boosters16,116can advantageously be independently varied depending on the desired flow characteristics of a specific application be simply changing the trim components. This is a cost-effective alternative to conventional designs where the entire volume booster must be replaced to change the supply and/or exhaust capacity.

In light of the foregoing, it should be appreciated that the volume boosters16,116described herein are merely examples of fluid control devices incorporating the principles of the present disclosure. Other fluid control devices may also benefit from the structures and/or advantages of the present disclosure without departing from the spirit and scope of the following aspects and/or attached claims.

Aspect 1: A fluid flow control device, comprising: a body comprising an inlet port, a common port, and a discharge port; a supply path extending between the inlet port and the common port; an exhaust path extending between the common port and the discharge port; a supply port disposed within the body along the supply path between the inlet port and the common port; a control element disposed within the body and adapted for displacement between a closed position in sealing engagement with the supply port to close the supply path, and an open position spaced from the supply port to open the supply path; a diaphragm assembly defining an exhaust port and disposed along the exhaust path between the common port and the discharge port, the diaphragm assembly adapted for displacement between a closed position, wherein the exhaust port is in sealing engagement with the control element to close the exhaust path, and an open position, wherein the exhaust port is spaced from the control element to open the exhaust path; and an exhaust trim component disposed within the body and defining an exhaust passage along the exhaust flow path between the common port of the body and the exhaust port of the diaphragm assembly, the exhaust passage having a first exhaust fluid flow resistance, the exhaust trim component removably attached to the body thereby enabling the exhaust trim component to be removed and substituted with another exhaust trim component having an exhaust passage with a second exhaust fluid flow resistance that is different than the first exhaust fluid flow resistance.

Aspect 2: The device of aspect 1, wherein the exhaust trim component comprises an exhaust bushing threaded into the body and the exhaust passage comprises at least one bore extending through the exhaust bushing.

Aspect 3: The device of any one of the preceding aspects, wherein the exhaust trim component is selected from a plurality of exhaust trim components, each of the plurality of exhaust trim components defining a distinct exhaust passage having a distinct exhaust fluid flow resistance.

Aspect 4: The device of any one of the preceding aspects, wherein each exhaust passage of the plurality of exhaust trim components comprises at least one bore.

Aspect 5: The device of any one of the preceding aspects, wherein each first exhaust passage of the plurality of exhaust trim components comprises at least one of a distinct cross-sectional dimension and a distinct longitudinal dimension.

Aspect 6: The device of any one of the preceding aspects, further comprising a supply trim component removably attached to the body and defining a supply passage disposed along the supply path between the inlet port and the supply port.

Aspect 7: The device of any one of the preceding aspects, wherein the supply trim component is selected from a plurality of supply trim components, each of the plurality of supply trim components defining a distinct supply passage having a distinct supply fluid flow resistance.

Aspect 8: The device of any one of the preceding aspects, wherein each supply passage of the plurality of supply trim components comprises at least one bore.

Aspect 9: The device of any one of the preceding aspects, wherein each supply passage of the plurality of exhaust trim components comprises at least one of a distinct cross-sectional dimension and a distinct longitudinal dimension.

Aspect 10: A fluid flow control device, comprising: a body comprising an inlet port, a common port, and a discharge port; a supply path extending between the inlet port and the common port; an exhaust path extending between the common port and the discharge port a supply port disposed within the body along the supply path between the inlet port and the common port an exhaust port disposed within the body along the exhaust path between the common port and the discharge port a control element disposed within the body and adapted for displacement between a closed position in sealing engagement with the supply port to close the supply path, and an open position spaced from the supply port to open the supply path; and an exhaust trim component removably attached to the body and defining an exhaust passage disposed along the exhaust path between the common port and the exhaust port, the exhaust passage having a first exhaust fluid flow resistance, the first exhaust fluid flow resistance pre-selected from a plurality of distinct exhaust fluid flow resistances thereby customizing an exhaust capacity of the fluid flow control device for a specific application.

Aspect 11: The device of aspect 10, wherein the first exhaust fluid flow resistance of the exhaust passage is a function of at least one of a cross-sectional dimension of the exhaust passage in the exhaust trim component and a longitudinal dimension of the exhaust passage trim component.

Aspect 12: The device of any one of aspects 10 to 11, wherein the exhaust trim component comprises an exhaust bushing threaded into the body and the exhaust passage comprises at least one cylindrical bore extending through the exhaust bushing.

Aspect 13: The device of any one of aspects 10 to 12, further comprising a supply trim component removably attached to the body and defining a supply passage disposed along the supply path between the inlet port and the supply port, the supply passage having a second fluid flow resistance, the second fluid flow resistance pre-selected from a plurality of distinct supply fluid flow resistances to customize the fluid flow control device for a specific application.

Aspect 14: The device of any one of aspects 10 to 13, wherein the second fluid flow resistance of the supply passage is a function of at least one of a cross-sectional dimension of the supply passage in the supply trim component and a longitudinal dimension of the supply passage in the supply trim component.

Aspect 15: The device of any one of aspects 10 to 14, wherein the supply trim component comprises a supply bushing threaded to the body and the supply passage comprises at least one cylindrical bore extending through the supply bushing.

Aspect 16: The device of any one of aspects 10 to 15, further comprising a diaphragm assembly defining the exhaust port and being disposed along the exhaust path between the exhaust passage of the exhaust trim component and the discharge port of the body, the diaphragm assembly adapted for displacement between a closed position wherein the exhaust port is in sealing engagement with the control element to close the exhaust path, and an open position wherein the exhaust port is spaced from the control element to open the exhaust path.

Aspect 17: A fluid flow control device, comprising: a body comprising an inlet port, a common port, and a discharge port; a supply path extending between the inlet port and the common port; an exhaust path extending between the common port and the discharge port a supply port disposed within the body along the supply path between the inlet port and the common port an exhaust port disposed within the body along the exhaust path between the common port and the discharge port a control element disposed within the body and adapted for displacement between a closed position in sealing engagement with the supply port to close the supply path, and an open position spaced from the supply port to open the supply path an exhaust trim component removably attached to the body and defining an exhaust passage along the exhaust path between the common port and the exhaust port; an a first selected set of dimensional parameters for the exhaust passage, the first selected set of dimensional parameters pre-selected from a first plurality of sets of distinct dimensional parameters, thereby customizing an exhaust capacity of the fluid flow control device for a specific application.

Aspect 18: The device of aspect 17, wherein each set of the first plurality of sets of dimensional parameters includes at least one of a distinct cross-sectional dimension of the exhaust passage and a distinct longitudinal dimension of the exhaust passage.

Aspect 19: The device of any one of aspects 17 to 18, wherein each set of the first plurality of sets of dimensional parameters defines at least one of a distinct exhaust fluid flow resistance for the exhaust passage and a distinct exhaust capacity for the exhaust passage.

Aspect 20: The device of any one of aspects 17 to 19, wherein the exhaust trim component comprises an exhaust bushing threaded into the body and the exhaust passage comprises at least one cylindrical bore extending through the exhaust bushing.

Aspect 21: The device of any one of aspects 17 to 20, further comprising a supply trim component removably attached to the body and defining a supply passage along the supply path between the inlet port and the supply port; and a second selected set of dimensional parameters for the supply passage, the second selected set of dimensional parameters pre-selected from a second plurality of sets of distinct dimensional parameters, thereby customizing a supply capacity of the fluid flow control device for a specific application.

Aspect 22: The device of any one of aspects 17 to 21, wherein each set of the second plurality of sets of dimensional parameters defines at least one of a distinct supply fluid flow resistance for the supply passage and a distinct capacity for the supply passage.

Aspect 23: The device of any one of aspects 17 to 22, wherein the supply trim component comprises a supply bushing threaded to the body and the supply passage comprises at least one cylindrical bore extending through the supply bushing.

Aspect 24: The device of any one of aspects 17 to 23, further comprising a diaphragm assembly defining the exhaust port and being disposed along the exhaust path between the exhaust passage of the exhaust trim component and the discharge port of the body, the diaphragm assembly adapted for displacement between a closed position wherein the exhaust port is in sealing engagement with the control element to close the exhaust path, and an open position wherein the exhaust port is spaced from the control element to open the exhaust path.

Aspect 25: A fluid flow control device, comprising: a body comprising an inlet port, a common port, and a discharge port; a supply path extending between the inlet port and the common port; an exhaust path extending between the common port and the discharge port; a supply port disposed within the body along the supply path between the inlet port and the common port; an exhaust port disposed within the body along the exhaust path between the common port and the discharge port; a control element disposed within the body and adapted for displacement between a closed position in sealing engagement with the supply port to close the supply path, and an open position spaced from the supply port the open the supply path; and an exhaust trim component removably attached to the body and defining an exhaust passage disposed along the exhaust path between the common port and the exhaust port, the exhaust trim component selected from a first exhaust trim component and a second exhaust trim component, the first exhaust trim component defining a first exhaust passage having a first exhaust fluid flow resistance, the second exhaust trim component defining a second exhaust passage having a second exhaust fluid flow resistance that is different than the first exhaust fluid flow resistance.

Aspect 26: The device of aspect 25, wherein the first exhaust passage comprises at least one bore through the first exhaust trim component and the second exhaust passage comprises at least one bore though the second exhaust trim component.

Aspect 27: The device of any one of aspects 25 to 26, wherein the first exhaust passage comprises a first cross-sectional dimension and the second exhaust passage comprises a second cross-sectional dimension that is different than the first cross-sectional dimension.

Aspect 28: The device of any one of aspects 25 to 27, wherein the first exhaust passage comprises a first longitudinal dimension and the second exhaust passage comprises a second longitudinal dimension that is different than the first longitudinal dimension.

Aspect 29: The device of any one of aspects 25 to 28, wherein the first and second exhaust trim components each comprise an exhaust bushing adapted to be threaded into the body of the fluid flow control device.

Aspect 30: The device of any one of aspects 25 to 29, further comprising a supply trim component removably attached to the body and defining a supply passage disposed along the supply flow path between the inlet port and the supply port.

Aspect 31: The device of any one of aspects 25 to 30, wherein the supply trim component is selected from a first supply trim component and a second supply trim component, the first supply trim component defining a first supply passage having a first supply fluid flow resistance, the second supply trim component defining a second supply passage having a second supply fluid flow resistance that is different than the first supply fluid flow resistance.

Aspect 32: The device of any one of aspects 25 to 31, wherein the first supply passage comprises at least one bore through the first supply trim component and the second supply passage comprises at least one bore though the second supply trim component.

Aspect 33: The device of any one of aspects 25 to 32, wherein the first supply passage comprises a third cross-sectional dimension and the second supply passage comprises a fourth cross-sectional dimension that is different than the third cross-sectional dimension.

Aspect 34: The device of any one of aspects 25 to 33, wherein the first supply passage comprises a third longitudinal dimension and the second supply passage comprises a fourth longitudinal dimension that is different than the third longitudinal dimension.

Aspect 35: The device of any one of aspects 25 to 34, wherein the first and second supply trim components each comprise a supply bushing adapted to be threaded into the body of the fluid flow control device.

Aspect 36: The device of any one of aspects 25 to 35, further comprising a diaphragm assembly defining the exhaust port and being disposed along the exhaust path between the exhaust passage of the exhaust trim component and the discharge port of the body, the diaphragm assembly adapted for displacement between a closed position wherein the exhaust port is in sealing engagement with the control element, thereby closing the exhaust path, and an open position wherein the exhaust port is spaced from the control element, thereby opening the exhaust path.

Aspect 37: A method of configuring a fluid flow control device comprising a volume booster for a specific application, the volume booster comprising a body defining a supply path and an exhaust path, the supply path extending from an inlet port, through a supply port, and to a common port, the exhaust path extending from the common port, through an exhaust port, and to a discharge port, the method comprising: determining a desired supply capacity for the supply path; selecting a supply trim component from a plurality of supply trim components based on the desired supply capacity for the supply flow path, each of the plurality of supply trim components defining a supply passage with a distinct supply fluid flow resistance; determining a desired exhaust capacity for the exhaust path; selecting an exhaust trim component from a plurality of exhaust trim components based on the desired exhaust capacity for the exhaust path, each of the plurality of exhaust trim components defining an exhaust passages with a distinct exhaust fluid flow resistance; removably installing the selected exhaust trim component into the body of the volume booster at a location along the exhaust path between the common port and the exhaust port; and removably installing the selected supply trim component into the body of the volume booster at a location along the supply path between the inlet port and the supply port.

Aspect 38: The method of aspect 37, wherein selecting the supply trim component comprises selecting a supply trim component having a passage that comprises at least one bore of a specific cross-sectional dimension to accommodate the desired supply capacity.

Aspect 39: The method of any one of aspects 37 to 38, wherein selecting the supply trim component comprises selecting a supply trim component having a passage that comprises at least one bore of a specific longitudinal dimension to accommodate the desired supply capacity.

Aspect 40: The method of any one of aspects 37 to 39, wherein selecting the exhaust trim component comprises selecting an exhaust trim component having a passage comprising at least one bore of a specific cross-sectional dimension to accommodate the desired exhaust capacity.

Aspect 41: The method of any one of aspects 37 to 40, wherein selecting the exhaust trim component comprises selecting a exhaust trim component having a passage that comprises at least one bore of a specific longitudinal dimension to accommodate the desired exhaust capacity.