Patent Description:
Conventional pressure regulators can include an inlet, an outlet, and a control element positioned between the inlet and the outlet. The control element can be mechanically linked to a diaphragm extending across an internal cavity of a diaphragm case, which is fluidly coupled to the inlet. At least one spring can be attached to the diaphragm within the diaphragm case and pre-tensioned or otherwise adjusted to provide a downward force on the diaphragm. When the pressure in the diaphragm case fluctuates relative to the spring force, the diaphragm can actuate the control element accordingly, via a connecting lever, to widen or narrow the flow path from the inlet to the outlet. Thus, pressure downstream of the regulator can be regulated based on a set point for the spring. Some pressure regulators can also include an internal relief valve to help ensure that downstream structures are not damaged in the event of a wide-open failure (i.e., a failure mode in which the control element is in an open position).

<CIT> discloses a fluid regulating device comprising a valve body carrying a valve port that defines an elongated orifice that converges from an inlet portion to an outlet portion. The converging orifice minimizes the effects of boundary layer separation and advantageously maximizes the flow capacity of the valve port. The elongated orifice can be defined by a one-piece body, which is threaded into the valve body, or by a cartridge slidably disposed in a housing, which is threaded into the valve body. The fluid regulating device further comprises a diaphragm-based actuator including a control element movably disposed within the valve body for controlling the flow of fluid therethrough.

<CIT> discloses a fluid regulator including a regulator body having a fluid inlet and a fluid outlet connected by a fluid flow path, with a portion of the regulator body forming a first chamber and a second chamber, an orifice disposed in the fluid flow path, a seat, and a control element disposed within the fluid flow path and shiftable between an open position spaced away from the seat and a closed position seated against the seat, with the control element arranged to respond to fluid pressure changes to control flow of a process fluid through the orifice. A first diaphragm having a radially inner portion is operatively coupled to the control element, and a second diaphragm having a radially inner portion also is operatively coupled to the control element.

According to the invention there is provided a pressure regulator as defined in claim <NUM>. Optional and/or preferable features are defined in the dependent claims.

In the first mode of operation, the lever can be connected to a stem and in the second mode of operation, the lever can be disconnected from the stem.

In some embodiments, when in a third position, the secondary control member can block a fluid flow path at an orifice assembly.

In some embodiments, the pressure regulator can include primary and secondary control members that move integrally with a stem.

In some embodiments, the pressure regulator can include primary and secondary control members that move in unison with each other.

In some embodiments, in the second mode of operation of the pressure regulator, the primary control member can be moved to a third position in which the primary control member is separated from the first side of the orifice assembly by a greater distance than when the primary control member is in the second position. In some cases, the primary control member being in the third position can correspond to the secondary control member being in the third position.

In some embodiments, the secondary control member contacting a second side of an orifice assembly can stop the primary control member (e.g., via a stem) from moving farther away from he first side of the orifice assembly.

In some embodiments, he secondary control member can include a disc that is configured to contact the second side of the office assembly when the secondary control member is in the third position.

In some embodiments, the secondary control member can include a ramped surface that is configured to contact the second side of the orifice assembly when the secondary control member is in the third position.

In some embodiments, the secondary control member can be configured to be moved to he third position, in the second mode of operation of the pressure regulator, solely by the pressure of the fluid along the fluid flow path.

In some embodiments, with the stem in the second position, the secondary control member can be separated from the second side of the orifice assembly by a smaller distance than when the stem is in the first position.

In some embodiments, the primary and secondary control members can cooperatively define a spacing therebetween so that a minimum flow area along the fluid flow path is defined, during the first mode of operation of the pressure regulator, by at least one of: a spacing between the primary control member and the first side of the orifice assembly, or a spacing between the secondary control member and the second side of the orifice assembly.

In some embodiments, engagement of the stem and the lever can stop movement of the stem in a valve-opening direction with the stem in the second position.

In some embodiments, a maximum flow capacity of the pressure regulator can be attained when the stem is in the second position.

In some embodiments, as the stem moves from the second position to the third position, corresponding movement of the secondary control member can continually decrease the flow capacity of the pressure regulator.

Some embodiments of the technology provide a pressure regulator that can include a valve body that defines a fluid flow path between an inlet and an outlet, an orifice assembly that is positioned along the fluid flow path, a lever configured to be moved by movement of a diaphragm in a first mode of operation of the pressure regulator, and a stem assembly. The stem assembly can include a stem, a primary control member, and a secondary control member. The stem can be operably coupled to the diaphragm (e.g., engaged with the lever) in the first mode of operation and can be operably decoupled from the diaphragm (e.g., disengaged from the lever) in a second mode of operation of the pressure regulator. The primary control member can be coupled to the stem on a downstream side of the orifice assembly, and the secondary control member can be coupled to the stem on an upstream side of the orifice assembly. In the first mode of operation, the stem can be movable between first and second orientations. With the stem in the first orientation, the primary control member can be in contact with a first side of the orifice assembly to block flow past the orifice assembly, and with the stem in the second orientation, the primary control member can be separated from the first side of the orifice assembly to permit flow past the orifice assembly. In the second mode of operation, the stem can be movable to a third orientation. The stem moving from the second orientation to the third orientation can move the secondary control member toward a second side of the orifice assembly to restrict flow past the orifice assembly.

In some embodiments, with a stem in first and second orientations, a secondary control member can be separated from a second side of an orifice assembly. With the stem in a third orientation, the secondary control member can contact the second side of the orifice assembly.

Some examples of the disclosure provide a stem assembly for a pressure regulator that can include a valve body that defines a fluid flow path between an inlet and an outlet, an orifice assembly that defines a flow orifice along the fluid flow path, and a lever that is configured to be moved by movement of a diaphragm. The stem assembly can include a stem that is configured to be moved by the lever in a first mode of operation of the pressure regulator and to move freely relative to the lever in a second mode of operation of the pressure regulator. A primary control member can be coupled to the stem, and a secondary control member can be coupled to the stem and can be spaced apart from the primary control member by an extension portion of the stem. The stem can be configured to be installed in the pressure regulator with the extension portion extending through the flow orifice defined by the orifice assembly, and with the primary control member positioned downstream of the flow orifice and the secondary control member positioned upstream of the flow orifice.

In some examples, a primary control member can be configured to contact a downstream side of an orifice assembly to restrict flow through the orifice assembly. A secondary control member can be configured to contact an upstream side of the orifice assembly to restrict flow through the orifice assembly. An extension portion of a stem can be sized so that: the secondary control member is separated from the upstream side of the orifice assembly when the primary control member contacts the downstream side of the orifice assembly, and the primary control member is separated from the downstream side of the orifice assembly when the secondary control member contacts the upstream side of the orifice assembly.

Some examples of the disclosure provide a pressure regulator that can include a valve body that defines a fluid flow path between an inlet and an outlet, an orifice assembly that is positioned along the fluid flow path, and a stem. A lever can be configured to control movement of the stem when engaged to the stem, as driven by movement of a diaphragm. A control member can be coupled to the stem, and a mechanical stop can be coupled to the stem. In a first mode of operation of the pressure regulator, the control member can be moveable relative the orifice assembly between a first position in which the control member contacts the orifice assembly to restrict fluid flow along the fluid flow path and a second position in which the control member is separated from the orifice assembly. The mechanical stop can be configured to engage a stop feature, in a second mode of operation of the pressure regulator, to prevent the control member from moving past a third position.

In some examples, in a first mode of operation, a lever can be connected to a stem. In the second mode of operation, the lever can be disconnected from the stem.

In some examples, in a first mode of operation, a lever, via a stem, can prevent a control member from moving past a second position toward a third position.

In some examples, a control member can be spaced father from an orifice assembly in a third position than in a second position.

In some examples, a mechanical stop can be formed as a ring that at least partially surrounds a stem.

In some examples, a pressure regulator can include a mechanical stop coupled to a stem. The mechanical stop can be formed as an elongated sleeve.

In some examples, a mechanical stop can be formed as an elongate sleeve.

In some examples, an elongate sleeve can be configured to be secured to a stem at a fixed location on the stem, so that a length of the elongate sleeve determines a distance between second and third positions of a control member.

In some examples, a first end of an elongate sleeve can be disposed adjacent to a connection assembly that secures a control member to a stem. A second end of the elongate sleeve, opposite the first end, can be configured to engage a stop feature to prevent the control member from moving past a third position.

In some examples, a stem can extend through a wall of a valve body between an orifice assembly and a lever. A mechanical stop can be disposed on the stem opposite the wall from the lever.

In some examples, a stop feature can be formed as part of a wall between an orifice assembly and a lever.

In some examples, a mechanical stop can be formed separately from a stem and can be configured to be installed onto the stem after installation of a pressure regulator for operation.

Some examples of the technology provide a pressure regulator that can include a valve body that defines a fluid flow path between an inlet and an outlet, an orifice assembly that is positioned along the fluid flow path, a lever configured to be moved by movement of a diaphragm in a first mode of operation of the pressure regulator, and a stop feature. A stem assembly can include a stem, a control member, and a mechanical stop. The stem can be connected by the lever to the diaphragm in the first mode of operation and not connected by the lever to the diaphragm in a second mode of operation of the pressure regulator. In the first mode of operation, the stem can be movable between first and second orientations, as controlled by the diaphragm via the lever. With the stem in the first orientation, the control member can be in contact with the orifice assembly to block flow past the orifice assembly. With the stem in the second orientation, the control member can be separated from the orifice assembly to permit flow past the orifice assembly. In the second mode of operation, the stem can be movable past the second orientation to a third orientation, in which the control member is spaced farther from the orifice assembly than when the stem is in the second orientation. The stop feature can be disposed to engage the mechanical stop, in the second mode of operation, to define the third orientation and to prevent movement of the stem past the third orientation.

In some examples, in a first mode of operation of a pressure regulator, a lever, via a stem, can prevent a control member from moving past a second orientation toward a third orientation.

In some examples, a mechanical stop can be formed as a ring that partially surrounds a stem.

In some examples, an elongate sleeve can be configured to be secured to a stem at a fixed location on the stem, so that a length of the elongate sleeve determines a distance between a second orientation and a third orientation of the stem.

In some examples, a first end of an elongate sleeve can be disposed adjacent to a connection assembly that secures a control member to a stem. A second end of the elongate sleeve, opposite the first end, can be configured to engage a stop feature to prevent the control member from moving past a third orientation.

In some examples, a pressure regulator can include a stem that extends through a wall of a valve body between an orifice assembly and a lever. A mechanical stop can be disposed on the stem opposite the wall from the lever.

Some examples of the technology provide a stem assembly for a pressure regulator. The pressure regulator can include a valve body that defines a fluid flow path between an inlet and an outlet, an orifice assembly that defines a flow orifice along the fluid flow path, a stop feature, and a lever that is configured to be moved by movement of a diaphragm. The stem assembly can include a stem, a control member, and a mechanical stop on the stem. The stem can be configured to be moved by the lever in a first mode of operation of the pressure regulator and to move freely relative to the lever in a second mode of operation of the pressure regulator. The control member can be coupled to the stem and can be configured to block or permit flow past the orifice assembly depending on an orientation of the stem. In the second mode of operation, the mechanical stop can be configured to engage the stop feature, upon movement of the lever in a first direction, to stop further movement of the stem in the first direction and thereby limit a spacing between the control member and the orifice assembly.

In some examples, a mechanical stop can be configured to engage a stop feature to limit the spacing between a control member and an orifice assembly to a maximum spacing. The control member, when at the maximum spacing from the orifice assembly, can restrict flow along a fluid flow path more than a flow orifice of the orifice assembly restricts flow along the fluid flow path.

The accompanying drawings, which are incorporated in and form a part of this specification, illustrate examples and embodiments of the invention in as much as they fall within the scope of the claims and, together with the description, serve to explain the principles of embodiments of the invention:.

The following discussion is presented to enable a person skilled in the art to make and use embodiments of the invention. Various modifications to the illustrated embodiments will be readily apparent to those skilled in the art, and the generic principles herein can be applied to other embodiments and applications without departing from embodiments of the invention as defined in the claims. The following detailed description is to be read with reference to the figures, in which like elements in different figures have like reference numerals. The figures, which are not necessarily to scale, depict selected embodiments and are not intended to limit the scope of embodiments of the invention.

Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the attached drawings. For example, the use of "including," "comprising," or "having" and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items.

As used herein, unless otherwise specified or limited, the terms "mounted," "connected," "supported," "secured," and "coupled" and variations thereof, as used with reference to physical connections, are used broadly and encompass both direct and indirect mountings, connections, supports, and couplings. Further, unless otherwise specified or limited, "connected," "attached," or "coupled" are not restricted to physical or mechanical connections, attachments or couplings.

As noted above, pressure regulators can be used to regulate the pressure of gas flows in a variety of contexts. In some configurations, a failure mode of a conventional pressure regulator can allow gas to flow relatively unimpeded through the pressure regulator. Accordingly, it may be necessary to size internal pressure relief valves or pressure relief valves at other locations to accommodate relatively large flow volumes or pressures. This can lead to substantial increases in overall cost and in system complexity.

Embodiments of the invention can address this issue, and others, including by providing mechanical devices that can automatically regulate pressure of a gas flow during possible failure-mode operation of a regulator, such as after lever-disconnect events. For example, in some embodiments, a stem assembly of a pressure regulator can include primary and secondary control members on opposing sides of an orifice assembly of the pressure regulator. Via movement of the stem, the primary control member can operate to block or permit flow across the orifice assembly during a first mode of operation (e.g., normal operation) and the secondary control member can operate to block or otherwise restrict flow across the orifice assembly during a second mode of operation (e.g., after a lever disconnect event or other failure).

As another example, in some embodiments, a mechanical stop can be provided on a stem of a pressure regulator. During a first mode of operation, the mechanical stop may permit the stem, and an associated control member, to move freely, in order to block or permit flow across an orifice assembly of the pressure regulator. In contrast, during a second (e.g., lever-disconnect) mode of operation, the mechanical stop can contact a stop feature of the pressure regulator to limit movement of the control member away from the orifice assembly and thereby limit a maximum flow capacity of the pressure regulator.

<FIG> depicts one example of a conventional pressure regulator <NUM>. The pressure regulator <NUM> is generally configured to use in an internal environment (e.g., in a residential building), but the pressure regulator <NUM> or other pressure regulators on which embodiments of the invention can be implemented can also be installed in an external environment (e.g., outdoors). In this example, the pressure regulator <NUM> includes a valve body <NUM>, a control assembly <NUM>, an actuator assembly <NUM>, and an internal relief valve <NUM>. In other examples, however, other configurations of pressure regulators are possible, including other configurations on which embodiments of the invention can be beneficially employed.

The valve body <NUM> defines a fluid inlet <NUM>, a fluid outlet <NUM>, and a fluid flow path <NUM>. The fluid flow path <NUM> extends between the fluid inlet <NUM> and the fluid outlet <NUM> when the pressure regulator <NUM> is in an open configuration (not shown). A flow orifice <NUM> is disposed in the valve body <NUM>, along the fluid flow path <NUM>, as defined by an orifice assembly <NUM> disposed between the fluid inlet <NUM> and the fluid outlet <NUM>. Although the orifice assembly <NUM> is shown as a single-piece insert with opposing (upstream and downstream) seats for control members, other orifice assemblies can be integrally formed with a valve body, or can be formed as multi-piece assemblies that collectively define a sealable flow orifice with one or more valve seats.

As further described below, the control assembly <NUM> is configured for displacement in the valve body <NUM>, relative to the orifice assembly <NUM>, to control the flow of fluid through the orifice <NUM>. In the embodiment illustrated, the control assembly <NUM> includes a control member configured as a valve plug <NUM>, a lever <NUM>, and a valve stem <NUM> that connects the valve plug <NUM> to the lever <NUM>, although other configurations are possible. When the pressure regulator <NUM> is in a closed configuration, as illustrated in <FIG>, the valve plug <NUM> is positioned against (i.e., seated on) the orifice assembly <NUM> thus blocking the flow of process fluid along the flow path <NUM> (i.e., preventing fluid at the inlet <NUM> from flowing to the outlet <NUM>).

The actuator assembly <NUM> is operatively connected to the valve body <NUM> to control the position of the control assembly <NUM> relative to the orifice assembly <NUM>. The actuator assembly <NUM> includes a housing <NUM>, a diaphragm <NUM> disposed within the housing <NUM>, and a linkage operatively connecting the diaphragm <NUM> to the control assembly <NUM>. The actuator housing <NUM> is formed of a diaphragm case <NUM> and a spring case <NUM> that are secured together, such as with one or more bolts connecting respective outer flanges of the cases <NUM>, <NUM>. The diaphragm <NUM> separates the housing <NUM> into a first chamber <NUM> and a second chamber <NUM>. The first chamber <NUM> is defined at least partly by one side of the diaphragm <NUM> and the diaphragm case <NUM>. The second chamber <NUM> is defined at least partly by the other side of the diaphragm <NUM> and the spring case <NUM>.

An exhaust vent <NUM> is formed in the spring case <NUM> and extends into the second chamber <NUM>. The exhaust vent <NUM> includes an orifice <NUM> that extends from a vent inlet <NUM> to a vent outlet <NUM>. The vent inlet <NUM> is in fluid communication with the second chamber <NUM> and the vent outlet <NUM> is in fluid communication with the surrounding ambient atmosphere, such that the exhaust vent <NUM> fluidly connects the second chamber <NUM> to the surrounding ambient atmosphere. Correspondingly, in some configurations, the second chamber <NUM> can be maintained at a pressure that is approximately equal to the pressure of the surrounding ambient atmosphere.

An internal relief valve <NUM> is formed in the diaphragm <NUM> and is regulated by a non-adjustable relief spring <NUM>. The internal relief valve <NUM> provides overpressure protection to the downstream system by relieving fluid through the diaphragm <NUM> to atmosphere in the event of overpressure. Any pressure above the start-to-discharge point of the non-adjustable relief spring <NUM> moves the diaphragm <NUM> off the relief seat <NUM> allowing excess pressure to discharge through the exhaust vent <NUM>.

To control flow through the regulator <NUM> during normal operation, a first end of the lever <NUM> is operatively connected to the linkage for the diaphragm <NUM> and a second end of the lever <NUM> is operatively connected to the valve stem <NUM>. Accordingly, movement of the diaphragm <NUM> in response to pressure changes in the first chamber <NUM> (and at the outlet <NUM>) causes the linkage to move the lever, as further detailed below, which shifts the control assembly <NUM> to maintain the process fluid within a pre-selected pressure range at the fluid outlet <NUM>.

The actuator assembly <NUM> also includes a control spring <NUM>, a first spring seat <NUM>, and a second spring seat <NUM>. The first spring seat <NUM> is disposed on top of the diaphragm <NUM> within the second chamber <NUM> of the actuator housing <NUM>, and receives and supports a first end of the control spring <NUM>. The second spring seat <NUM>, which likewise is disposed within the second chamber <NUM>, receives a second end of the control spring <NUM> opposite the first end. So arranged, the control spring <NUM> biases the diaphragm <NUM> in a direction against the fluid pressure (e.g., a downward direction in the orientation shown in <FIG>) with a selected force, to maintain the pressure of the process fluid within the pre-selected range at the fluid outlet <NUM>. The force exerted by the control spring <NUM> can be adjusted via the second spring seat <NUM> or via any other known means, e.g., an adjusting screw. As illustrated in <FIG>, the actuator assembly <NUM> may also include components such as, for example, a valve plug and a release spring that are disposed in the internal relief valve <NUM> and serve to damp the response of the pressure regulator <NUM>.

As noted briefly above, with the pressure regulator <NUM> configured as shown, the diaphragm-based actuator assembly <NUM> controls the position of the valve plug <NUM> of the control assembly <NUM>, relative to the orifice assembly <NUM>, to satisfy desired process control parameters (e.g., a desired set-point pressure). The spring <NUM> of the actuator assembly <NUM> naturally biases the diaphragm <NUM> downward relative to the orientation of <FIG>, which translates, via the lever <NUM>, into a bias of the control assembly <NUM> toward an open position (i.e., with the valve plug <NUM> positioned away from the orifice assembly <NUM>). However, an increase in pressure at the outlet <NUM>, as communicated to the first chamber <NUM> (e.g., via a throat across the wall <NUM>), can urge the diaphragm <NUM> upward. Sufficient pressure increase at the outlet <NUM> can thereby overcome the force applied by the spring <NUM> to move the diaphragm <NUM> (e.g., upward in the orientation shown in <FIG>). This movement of the diaphragm, in turn, can move the lever <NUM>, the valve stem <NUM>, and the valve plug <NUM> toward the closed position (as shown in <FIG>). In contrast, when the fluid pressure at the outlet <NUM> decreases sufficiently, such as in response to an increase in fluid demand downstream of the pressure regulator <NUM>, the spring <NUM> can overcome the decreased fluid pressure in the first chamber <NUM> and move the diaphragm <NUM> (e.g., downward) to move the lever <NUM>, the valve stem <NUM>, and the valve plug <NUM> back toward the open position.

During use, the pressure regulator <NUM> can be subject to vibration-induced wear or other adverse effects. In some cases, this can result in a disconnect failure, in which the lever <NUM> disconnects from the valve stem <NUM>, or the mechanical link from the diaphragm <NUM> to the valve stem <NUM> is otherwise broken. A disconnect failure, or other component failures such as diaphragm <NUM> perforation, can sometimes lead to wide-open type failures, in which the control assembly <NUM> remains uncontrollably open and the pressure regulator <NUM> is no longer able to satisfactorily regulate flow. Thus, for example, the internal relief valve <NUM> as described above, or other downstream relief valves, can be provided for overpressure protection. However, in high volume flow applications, appropriately sized relief valves may be bulky, costly, or otherwise less than desirable. For example, in order to effectively provide overpressure protection, the size of the internal relief valve <NUM> (or other relief valve) may be partly dictated by the size of orifice <NUM>, which may be relatively large in high volume flow applications.

As also noted above, in view of these issues and others, it can be useful to provide a control assembly having a secondary control member or a mechanical stop to help to block or otherwise restrict flow through a pressure regulator, including during operation after a lever-disconnect failure or other failure event. In this way, for example, the size of an internal or other relief valve (e.g., the valve <NUM>) can be reduced in size, because the need to match the relief valve to the full capacity of a main orifice of the regulator (e.g., the orifice <NUM>) can be reduced. Accordingly, in some embodiments and as further detailed below, a secondary control member can be coupled to a valve stem to restrict fluid flow from an upstream side of a regulator orifice, or a mechanical stop can be coupled to the valve stem to limit travel of the valve stem in some operating modes.

<FIG> illustrate a control assembly <NUM> according to embodiments of the invention that include different secondary control members. Generally, the control assembly <NUM> can be used in a variety of different pressure regulators, including those configured similarly to the pressure regulator <NUM> (see <FIG>), with a main flow orifice through an orifice assembly and a diaphragm that is configured to move a lever to control flow through the main flow orifice. For example, the pressure regulator <NUM> can be modified to include part or all of the control assembly <NUM>, can be originally manufactured with the control assembly <NUM>, or can be retrofitted to receive the control assembly <NUM> in place of the control assembly <NUM> as illustrated in <FIG>. Accordingly, for the example presented herein, the control assembly <NUM> is discussed in the context of the orifice <NUM> and the orifice assembly <NUM>. In other embodiments, however, the control assembly <NUM> or other control assemblies according to the invention can be used with other orifice assemblies.

In the illustrated embodiment, the control assembly <NUM> includes a lever <NUM>, which is configured to be attached to an actuator assembly (e.g., the assembly <NUM> shown in <FIG>) and a stem assembly <NUM>. The stem assembly <NUM> has a primary control member <NUM> and a secondary control member <NUM>, both of which are secured to a valve stem <NUM>. The primary control member <NUM> can be configured as a valve plug or disc, or another mechanical structure or assembly that can selectively limit flow through an orifice (e.g., the orifice <NUM> of <FIG>). The lever <NUM> is mechanically coupled to a distal end of valve stem <NUM>, and the primary and secondary control members <NUM>, <NUM> are mechanically (e.g., rigidly) coupled to a proximal end of the valve stem <NUM>. In some embodiments, the primary and secondary control members <NUM>, <NUM> can be molded together as a unitary part with a portion of, or all of, the valve stem <NUM>. In some embodiments, the control members <NUM>, <NUM> can be separately formed and then later secured (e.g., pinned or clipped) to the valve stem <NUM>.

To accommodate flow through the relevant regulator orifice, the primary and secondary control members <NUM>, <NUM> are spaced apart from each other on the valve stem <NUM>. In particular, an extension portion <NUM> of the stem extends between the primary and secondary control members <NUM>, <NUM>. In some embodiments, the extension portion <NUM> can be separate from a main rod of the valve stem <NUM>, and can exhibit a different diameter or composition from the main rod. In some embodiments, the extension portion <NUM> can be integrally formed with one or more of the control members <NUM>, <NUM> or the main rod of the valve stem <NUM>.

Usefully, the extension portion <NUM> exhibits a length that is sized so that, when the control assembly <NUM> is installed for use, the primary control member <NUM> is positioned on the downstream side <NUM> of the orifice assembly <NUM>, the secondary control member <NUM> is positioned on the upstream side <NUM> of the orifice assembly <NUM>, and the extension portion <NUM> of the valve stem <NUM> extends through the orifice <NUM> defined by the orifice assembly <NUM>. With this arrangement, flow through the orifice assembly <NUM> can be restricted (e.g., blocked) on either side <NUM>, <NUM>, by the primary control member <NUM> or the secondary control member <NUM>, respectively. For example, as the control assembly <NUM> is actuated by a diaphragm, the primary and secondary control members <NUM>, <NUM>, can restrict flow by partially or completely sealing the corresponding downstream or upstream side <NUM>, <NUM> of the orifice assembly <NUM>.

In different embodiments, control members can exhibit different forms. For example, in <FIG>, the primary control member <NUM> is a solid disk having a chamfered edge on the non-sealing side, and in <FIG>, the secondary control member <NUM> is a solid disk without a chamfered edge. In other embodiments, however, other configurations are possible, including compound configurations (i.e., multi-piece or multimaterial configurations) and configurations with geometries other than those shown in <FIG> (e.g., as illustrated for the valve plug <NUM> in <FIG>).

As one example of an alternative configuration for a control member, as shown schematically in <FIG>, a secondary control member 234A includes passageways <NUM> that allow a secondary fluid flow into the fluid inlet <NUM>, including when the secondary control member <NUM> contacts the upstream side <NUM> of the orifice assembly <NUM>. As another example, as shown in <FIG>, a secondary control member 234B can include a ramped profile that faces towards and is configured to seat against with the upstream side <NUM> of the orifice assembly <NUM>. Accordingly, flow can be more gradually restricted as the valve stem <NUM> moves the control member <NUM> towards the orifice assembly <NUM>.

In other embodiments, other configurations are also possible. For example, a ramped profile of a secondary control member may be configured differently than shown in <FIG>, in order to provide any number of desired flow control characteristics as the secondary control member is moved relative to an orifice assembly. And ramped or other profiles can be otherwise customized in order to provide any variety of continuously increasing (or other) flow restrictions as a secondary control member is moved continuously toward an orifice assembly. In some embodiments, a secondary control member can be configured as a cage, or otherwise configured to include other through-hole arrangements, such as may allow a secondary fluid flow (e.g., similar to the configuration of <FIG>). Thus, depending on the needs of a particular application, a secondary control member can be configured to restrict flow across a regulator orifice in a variety of ways, including by fully or partially blocking fluid flow when in a fully closed position (e.g., when seated against the relevant orifice assembly).

Generally, valve stem assemblies with multiple control members, according to embodiments of the invention, can be used to regulate flow in multiple different modes of operation of a regulator. For example, the control assembly <NUM> can generally regulate flow through the orifice <NUM> during at least two modes of operation of the relevant pressure regulator. In a first, "attached" mode of operation, the stem <NUM> is mechanically coupled to the lever <NUM> (see, e.g., <FIG> and <FIG>) to transmit movement between the relevant diaphragm and the valve stem <NUM>, as would be the case during normal operation of the pressure regulator <NUM>. During attached operation, the control assembly <NUM> is translated within the regulator body <NUM> by the relevant actuator assembly, so that movement of the relevant diaphragm in response to pressure changes causes the lever <NUM> to move the stem assembly <NUM>.

For the illustrated embodiment, the control assembly <NUM> is configured to move continuously between two orientations, as illustrated in <FIG> and <FIG>, when operating in the attached operation mode. Generally, as controlled by the lever <NUM>, the valve stem <NUM> can freely move between the first and a second orientation during attached operation, although some embodiments may include other control devices that may also affect movement of the valve stem <NUM>.

In particular, <FIG> shows the valve stem <NUM> in a first orientation, in which the primary and secondary control members <NUM>, <NUM> are in respective first positions. In the embodiment illustrated, the primary control member <NUM> is fully seated against the orifice assembly <NUM> in the first position and the fluid flow along a flow path through the regulator (and across the orifice <NUM>) is fully blocked. In contrast, the secondary control member <NUM> is spaced apart from a seat of the orifice assembly <NUM> in the first position, such that the secondary control member <NUM> may provide minimal restriction of flow through the orifice <NUM> as the valve stem <NUM> begins to move the primary control member <NUM> away from the orifice assembly <NUM> to permit flow through the orifice <NUM>.

<FIG> (and <FIG>) show the valve stem <NUM> in a second orientation, in which the primary and secondary control members <NUM>, <NUM> are in respective second positions. In particular, both of the control members <NUM>, <NUM> are separated (i.e., spaced apart) from respective sides <NUM>, <NUM> of the orifice assembly <NUM>, so that neither of the control members <NUM>, <NUM> fully block flow through the orifice <NUM>.

Depending on the collective configurations of the control members <NUM>, <NUM>, the extension portion <NUM>, and the orifice assembly <NUM>, the control members <NUM>, <NUM> may still somewhat restrict flow through the orifice <NUM> when the valve stem <NUM> is in the second orientation. In some embodiments, as also discussed below, the control members <NUM>, <NUM> can be configured to be separated from the respective sides <NUM>, <NUM> of the orifice assembly <NUM>, when the valve stem <NUM> is in the second orientation, to allow a maximum operational flow capacity through the orifice <NUM>. In this regard, for example, the engagement of the valve stem <NUM> with the lever <NUM>, with the valve stem <NUM> in the second orientation, can prevent further movement of the valve stem <NUM> in a valve-opening direction (e.g., to the right in <FIG>) and thereby, in cooperation with the orifice assembly <NUM> and one or both of the control members <NUM>, <NUM>, define the maximum operational flow capacity of the pressure regulator <NUM>. In other embodiments, however, other positions of the valve stem <NUM> may correspond to a maximum operational flow capacity.

Continuing, in some embodiments, a second "disconnected" mode of operation can be characterized by a component failure within a pressure regulator, such as diaphragm perforation, a disconnect failure between a lever and a valve stem or a lever and a linkage, or other conditions that may prevent a diaphragm from regulating flow through the pressure regulator. During operation in a disconnected mode of operation, a secondary control member can generally provide a backstop against excessive flow, with the pressure of fluid flow through the relevant regulator tending to move the secondary control member towards the relevant orifice assembly and thereby to decrease the current flow capacity of the regulator as a whole.

As one example, a disconnected mode can be characterized by disconnect of the lever <NUM> from the valve stem <NUM>, as shown in <FIG> (and <FIG>). In this case, the lever <NUM> may accordingly no longer prevent the valve stem <NUM> from moving in the valve-opening direction. In conventional regulators (e.g., as shown in <FIG>), this may result in essentially unrestricted flow across the orifice <NUM>. However, as the pressure of fluid moving through the regulator bears on the control members <NUM>, <NUM>, the valve stem <NUM> can be moved from the second orientation (see, e.g., <FIG>) towards a third orientation (see, e.g., <FIG>), with the secondary control member <NUM> correspondingly moving towards the upstream side <NUM> of the orifice assembly <NUM>. Accordingly, with sufficient pressure, the primary and secondary control members <NUM>, <NUM> can be moved into respective third positions, with the secondary control member <NUM> in particular being moved to be seated on the upstream side <NUM> of the orifice assembly <NUM>.

As shown in <FIG>, the primary control member <NUM> is separated from the downstream side <NUM> of the orifice assembly <NUM> at a greater distance when moving to, and when in, the third position than when in the second position. This configuration can correspond to the primary control member <NUM> imposing reduced flow restriction at the downstream side <NUM> of the orifice assembly <NUM>. But the corresponding movement of the secondary control member <NUM> towards the orifice assembly <NUM> can counterbalance this effect, with a continual increase in flow restriction at the upstream side <NUM> of the orifice assembly <NUM> as the secondary control member <NUM> moves towards the orifice assembly <NUM>, and a corresponding continual decrease in operational flow capacity of the pressure regulator.

In some embodiments, as illustrated in <FIG>, a third position of a secondary control member can include the secondary control member seating against the relevant orifice assembly, although other configurations are also possible. Accordingly, depending on the configuration of the secondary control member and the orifice assembly, the third position may correspond with a complete blockage of flow past the orifice assembly, such that the secondary control member can effectively stop flow through the regulator. For example, when configured as a solid disc or other impermeable component, as illustrated for the secondary control member <NUM> in <FIG>, a secondary control member can fully block flow through a regulator when seated against the orifice assembly.

In other embodiments, however, other configurations are possible. In some embodiments, a secondary control member can be configured to restrict, but not fully block, flow through the pressure regulator during disconnected (or other second-mode) operation. For example, a secondary control member can be formed to include a cage (not shown) facing toward the relevant orifice assembly, so that some flow past the orifice assembly may be permitted even when the secondary control member is seated on the orifice assembly. Similarly, as also discussed above, a secondary control member can include passageways (e.g., the passageways <NUM> in <FIG>), that can allow a secondary fluid flow past an orifice assembly even when the secondary control member is seated on the orifice assembly. In such embodiments, the dimensions and other geometry of the relevant passageways (e.g., the passageways <NUM>) or of a cage feature can be selected to define a restricted minimum flow capacity during extended operation in a disconnected (or other) mode. Consistent with other discussion herein, such a restricted minimum flow capacity can sometimes usefully be selected so that a particular internal (or other) relief valve is capable of relieving or otherwise appropriately controlling the maximum possible flow during the disconnected (or other) mode.

As also noted above, in some embodiments, a spacing of control members along a valve stem (e.g., a length of an extension portion) can be configured to provide desired characteristics of operational flow restrictions in different operational modes. In some embodiments, primary and secondary control members may be spaced apart from each other so that movement of the secondary control member towards the orifice assembly during attached operation may not overly restrict overall flow. For example, a minimum spacing of a secondary control member from an orifice assembly during attached operation may be selected to restrict flow into a relevant orifice by no more than the maximum spacing of the primary control member from the orifice assembly during attached operation. In this way, for example, the secondary control member may substantially affect flow through the regulator only upon entry into a disconnected mode, when the secondary member is able to move closer to the orifice assembly.

As one example, as illustrated in <FIG>, with the valve stem <NUM> in the second orientation during attached operation, a minimum distance W1 is defined between the secondary control member <NUM> and the upstream side <NUM> of the orifice assembly <NUM>, and a maximum distance W2 is defined between the primary control member <NUM> and the downstream side <NUM> of the orifice assembly <NUM>. In particular, in the embodiment illustrated, the extension portion <NUM> is sized so that when the engagement of the valve stem <NUM> with the lever <NUM> constrains the movement of the valve stem <NUM>, the distance W1 and the distance W2 are substantially equal to each other. In this way, for example, in view of the equivalent diameter of the orifice <NUM> at upstream and downstream sides <NUM>, <NUM> of the orifice assembly <NUM>, the maximum attached-mode flow capacity of the regulator, is controlled by primary control member <NUM> and the distance W2 and is not restricted by the secondary control member <NUM> and the distance W1.

In other embodiments, however, other configurations are possible. For example, in some embodiments, the extension portion <NUM> can be sized so that, when the lever <NUM> stops movement of the valve stem <NUM> in the valve-opening direction, W1 is less than W2. Thus, depending also on the configuration of the orifice <NUM> and the orifice assembly <NUM>, W1 may define the maximum flow capacity at a fully open configuration. In some embodiments, in contrast, when the lever <NUM> stops movement of the valve stem <NUM> in the valve-opening direction, W1 may be greater than W2. Further, as also noted above, the absolute size of the distances between control members and an orifice assembly may not be fully determinative of flow capacity. For example, flow capacities may also be affected by different diameters or other varied geometries at upstream or downstream ends of an orifice, by different geometries of the control members (e.g., ramped geometries, as shown in <FIG>), or other factors, and design of control members, extension portions, and other features can be optimized accordingly to provide desired operational flow control.

Thus, some embodiments of the invention can provide improved performance for regulators, including during operation in disconnected modes. For example, upon a lever disconnect event, a secondary control member can be automatically moved by flow through a regulator to restrict (e.g., block) flow through the regulator. In some cases, this arrangement can protect downstream devices from overpressure and generally reduce the required flow capacity of internal or downstream relief valves.

As also noted above, some embodiments can include other features to provide flow control during multiple modes of operation of a regulator, such as mechanical stops on a stem assembly that are configured to contact stop features of a regulator to physically limit movement of the stem assembly. In this regard, for example, <FIG> illustrate the pressure regulator <NUM> outfitted with different configurations of a control assembly <NUM> according to an embodiment of the invention. Generally, the pressure regulator <NUM> can be modified to include the control assembly <NUM>, can be originally manufactured with the control assembly <NUM>, or can be retrofitted to receive the control assembly <NUM>. Further, in some embodiments, control assemblies similar to the control assembly <NUM> can be used in regulators configured differently than the regulator <NUM>.

The control assembly <NUM> generally includes a lever <NUM> and a stem assembly <NUM>. As similarly discussed relative to the configuration of the conventionally configured regulator <NUM> of <FIG>, the lever <NUM> is mechanically coupled to the distal end of the valve stem <NUM>, and the control member <NUM> is coupled to the proximal end of the valve stem <NUM>. Thus, during an attached mode of operation, movement of the diaphragm <NUM> can move the lever <NUM> to move the valve stem <NUM> and thereby control flow through the regulator <NUM>.

In the embodiment illustrated in <FIG>, the stem assembly <NUM> has a control member <NUM>, a mechanical stop <NUM>, and a valve stem <NUM>, with the control member <NUM> and the mechanical stop <NUM> on an opposite side of the wall <NUM> from the lever <NUM> (i.e., on the same side of the wall <NUM> as the orifice assembly <NUM>). During operation, the mechanical stop <NUM> is configured to engage a stop feature that is incorporated into the pressure regulator <NUM> as further described below.

Similar to the control member <NUM> (see, e.g., <FIG>), the control member <NUM> can be configured as a valve plug or disc, or another mechanical structure that can selectively limit flow though a regulator orifice (e.g., the orifice <NUM>) via interaction with an orifice assembly (e.g., the orifice assembly <NUM>). In the illustrated embodiment, the control member <NUM> is coupled to the valve stem <NUM> by way of a connection assembly <NUM>, which can include a weld, pins, mechanical mating features, or any other appropriate structure to couple the control member <NUM> to the valve stem <NUM>. In other embodiments, other configurations are possible, including configurations with control members that are integrally formed with corresponding valve stems.

In different embodiments, a mechanical stop can be configured in different ways. In some embodiments, a mechanical stop can be configured as a ring that at least partially surrounds a valve stem. For example, <FIG> illustrates the mechanical stop <NUM> as a ring that is formed as an elongate sleeve (i.e., a sleeve having an axial length that is greater than a radius thereof) and that extends along the longitudinal axis of the valve stem <NUM>. In other embodiments, however, other configurations are possible. For example, a mechanical stop configured as a ring can be formed as a disc or generally ring-shaped clip that extends radially outward from the relevant valve stem.

In different embodiments, a mechanical stop can be secured to a valve stem in different ways and at different locations, in order to contact a stop feature and thereby stop movement of the associated control member when the control member is at a particular position within the regulator. For example, a ring shaped mechanical stop can be secured via grooves or ridges (not shown) on a valve stem, using set screws, using snap-on or press-fit connections, using non-threaded pins, or in a variety of other ways. Similarly, mechanical stops can generally be secured to fixed locations on the relevant valve stems, which can be selected from any number of locations along the length of valve stems. Further, some configurations of mechanical stops can be selected to exhibit one (or more) of any variety of lengths. For example, <FIG> illustrates two possible lengths A, B for the mechanical stop <NUM>. In some embodiments, a mechanical stop can be indirectly coupled to a valve stem, such as by direct coupling of the mechanical stop to a control element or to a connection assembly that secures a control element to a valve stem.

Generally, as also noted above, when a valve stem equipped with a mechanical stop moves sufficiently beyond a permitted (e.g., first-mode) range of positions, to reach a predetermined (e.g., second-mode) maximum-displacement position, a mechanical stop can contact a corresponding stop feature (or features) to prevent further movement of the associated valve stem. Accordingly, for example, similarly to control assemblies with secondary control members (e.g., the control assembly <NUM>), control assemblies with mechanical stops and stop features can provide flow control in at least two modes of operation: e.g., attached operation and disconnected operation, as described above.

For example, during attached operation of the regulator <NUM> as equipped with the control assembly <NUM>, the valve stem <NUM> can move between first and second orientations, with the control member <NUM> and the mechanical stop <NUM> in first and second corresponding positions, respectively, for generally conventional control of flow through the regulator <NUM>. In particular, during attached operation, the valve stem <NUM> can move the control member <NUM> from a first position in which the control member <NUM> seats against the orifice assembly <NUM> and fluid flow through the orifice <NUM> is fully blocked, and a second position (not shown) similar to the configuration of <FIG>, in which the control member <NUM> is spaced apart from the orifice assembly <NUM> to allow flow (e.g., maximum or unrestricted attached-mode flow) through the orifice <NUM>.

Notably, for the illustrated embodiment, in both the first and second orientations of the valve stem <NUM> (and throughout attached-mode operation), the mechanical stop <NUM> does not interact with a stop feature. Accordingly, during attached operation, although the engagement of the valve stem <NUM> with the lever <NUM> prevents the valve stem <NUM> from moving past the second orientation in a valve-opening direction, the mechanical stop <NUM> does not affect operation of the regulator <NUM>.

In contrast, during disconnected operation, the valve stem <NUM> can move past the second orientation in a direction extending away from the orifice assembly <NUM>, with corresponding increase in the permitted flow through the regulator <NUM>. However, movement of the valve stem <NUM> sufficiently past the second orientation will eventually bring the mechanical stop <NUM> into a third position (see <FIG>) in which the mechanical stop <NUM> contacts a stop feature and thereby stops the valve stem <NUM> at a third orientation, with corresponding third positions for the mechanical stop <NUM> and the control element <NUM>. Thus, for example, when the lever is disconnected from the valve stem <NUM> or the diaphragm <NUM> otherwise fails to control movement of the valve stem <NUM>, the mechanical stop <NUM> can engage the relevant stop feature to limit a maximum permitted restriction at the orifice <NUM> and thereby prevent unrestrained flow through the regulator <NUM>.

In different embodiments, different types and orientations of stop features can be used, including for stop features that are integral or preexisting features of a conventional regulator. For example, as illustrated in <FIG>, the wall <NUM> between the main flow path <NUM> of the regulator and the first chamber <NUM> provides a stop feature that contacts the sleeve of the mechanical stop <NUM> and thereby stops movement of the valve stem <NUM> in a valve opening direction once the mechanical stop <NUM>, the valve stem <NUM>, and the control element <NUM> reach the third positions (see <FIG>). In this regard, for example, the length and mounting location of the mechanical stop <NUM> along the valve stem <NUM> can be selected so that the mechanical stop <NUM> contacts the wall <NUM> when the control member <NUM> is an appropriate distance from the orifice assembly <NUM>, such as may correspond to a maximum permitted flow restriction for disconnected-mode operation. Generally, in the third orientation, the control member <NUM> is separated from the downstream side <NUM> of the orifice assembly <NUM> by a greater distance than when the valve stem <NUM> is in the second orientation, but by a smaller distance than may occur if no mechanical stop is employed. Thus, although the mechanical stop <NUM> may not stop flow through the regulator <NUM>, it may nonetheless limit flow to below an otherwise possible maximum.

As also noted above, mechanical stops can be formed and installed in a variety of different ways. As shown in <FIG>, for example, a mechanical stop is formed as a pin <NUM> that extends through the valve stem <NUM>, along an axis perpendicular to the longitudinal axis of the valve stem <NUM>. The pin <NUM> can be mechanically coupled to the valve stem <NUM> in a number of locations, such as at location X or at location Y, with similar effects to changes in location or length of a sleeve (e.g., the mechanical stop <NUM>) as discussed above. Also similarly to the mechanical stop <NUM>, the pin <NUM> is configured to operate with the wall <NUM> as a stop feature, although other physical structures (e.g., other features on the valve body <NUM>) can be used as stop features in other configurations. Accordingly, in an unattached mode of operation, contact between the pin <NUM> and the wall <NUM> can prevent the valve stem <NUM> from moving beyond a third position (not shown) in the valve-opening direction (i.e., to the right in <FIG>).

In some embodiments, a mechanical stop can be formed as a cavity or other recessed feature, which may be configured to receive a corresponding stop feature. For example, as illustrated in <FIG>, a mechanical stop is formed as a slot <NUM> in the valve stem <NUM>. Correspondingly, a stop feature <NUM> is formed to extend into the slot <NUM> and to contact an end of the slot <NUM> (e.g., to the left, as shown) to prevent movement of the valve stem <NUM> past a certain orientation (not shown). The stop feature <NUM> can be formed in a variety of ways, including as an integral part of the wall <NUM>, or other part of the regulator body <NUM>, as part of a U-shaped or other bracket secured to the wall <NUM> within the chamber <NUM>, a straight, L-shaped, or other pin that extends from the wall <NUM>, the casing <NUM>, or the casing <NUM>, or otherwise. Thus arranged, for example, contact between the stop feature <NUM> and the ends of the slot <NUM> prevents translation of the valve stem <NUM> within the pressure regulator <NUM> so that the movement of valve stem <NUM> is bounded by the ends of the slot <NUM>, relative to the location of the stop feature <NUM>.

As also discussed above, the degree of flow restriction provided during disconnected (or other second-mode) operation can generally be controlled by the interaction between a mechanical stop and a corresponding stop feature. Accordingly, the geometry and placement of a mechanical stop and a stop feature can sometimes be selected based on the degree of flow restriction desired in a mode of operation in which the mechanical stop can contact the stop feature (e.g., during disconnected operation). For example, with regard to <FIG>, the desired flow capacity out of the outlet <NUM> during disconnected operation can be selected, and the corresponding maximum distance that control member <NUM> can travel in the valve-opening direction (e.g., to the right, as shown) can then be calculated. The geometry and placement of the mechanical stops <NUM>, <NUM>, <NUM> and the corresponding stop features <NUM>, <NUM>, <NUM> can then be selected, as appropriate, based on the calculated maximum travel distance for the control member <NUM>.

For example, the length of the sleeve of the mechanical stop <NUM> and the location of the sleeve on the valve stem <NUM> can be selected so that when the valve stem <NUM> is in the first orientation (see <FIG>), the distance between the end of the mechanical stop <NUM> and the wall <NUM> is substantially equal to the desired maximum travel distance of the control member <NUM>. Accordingly, the mechanical stop <NUM> and the stop feature <NUM> can restrict the fluid flow through the fluid outlet <NUM> to be less than the fluid flow would be if the orifice <NUM> were completely unrestricted during disconnected operation. Similarly, the location and size of the pin <NUM>, the slot <NUM>, and the mechanical stop <NUM> can be selected, as desired, to ensure that flow through the regulator <NUM> can be appropriately restricted, even upon the lever <NUM> becoming disconnected from the valve stem <NUM>.

For the embodiments illustrated in <FIG>, the mechanical stops <NUM>, <NUM>, <NUM> and the stop features <NUM>, <NUM>, <NUM> are configured to enforce flow restrictions only during second-mode operation (e.g., not when the regulator <NUM> is operating normally). However, in some embodiments, the geometry and placement of a mechanical stop and a corresponding stop feature can be selected so that movement of a control element and, correspondingly, flow through the regulator can be restricted by the mechanical stop during attached operation.

Accordingly, the control assembly <NUM> can protect downstream devices from overpressure and reduce the required flow capacity of the internal relief valve <NUM> or other downstream relief valves. Thus, further embodiments of the invention can also provide improved performance for regulators, including through improvement over conventional flowcontrol assemblies. For example, upon a lever disconnect event, a mechanical stop control member can be automatically moved into contact with a stop feature to limit maximum flow through a regulator. In some cases, this arrangement can protect downstream devices from excessive overpressure and generally reduce the required flow capacity of internal or downstream relief valves.

Claim 1:
A pressure regulator (<NUM>) comprising:
a valve body (<NUM>) that defines a fluid flow path between an inlet (<NUM>) and an outlet (<NUM>);
an orifice assembly (<NUM>) that is positioned along the fluid flow path, the orifice assembly including a first side (<NUM>) and a second side (<NUM>) opposite the first side;
a stem (<NUM>, <NUM>);
a lever (<NUM>, <NUM>) configured to control movement of the stem when engaged with the stem, as driven by movement of a diaphragm (<NUM>);
a primary control member (<NUM>, <NUM>) that is coupled to the stem, wherein, in a first mode of operation of the pressure regulator, the primary control member (<NUM>, <NUM>) is moveable relative to the first side (<NUM>) of the orifice assembly (<NUM>), by movement of the stem (<NUM>, <NUM>), between: a first position in which the primary control member (<NUM>, <NUM>) contacts the first side (<NUM>) of the orifice assembly (<NUM>) to restrict fluid flow along the fluid flow path, and a second position in which the primary control (<NUM>, <NUM>) member is separated from the first side (<NUM>) of the orifice assembly (<NUM>); and
a secondary control member (<NUM>, <NUM>) that is coupled to the stem (<NUM>, <NUM>) and is movable relative to the second side (<NUM>) of the orifice assembly (<NUM>), by movement of the stem (<NUM>, <NUM>), wherein:
in the first mode of operation of the pressure regulator, the secondary control member (<NUM>, <NUM>) is moveable between a first position and a second position, in each of which the secondary control member (<NUM>, <NUM>) is separated from the second side (<NUM>) of the orifice assembly (<NUM>); and
in a second mode of operation of the pressure regulator, the secondary control member (<NUM>, <NUM>) is movable to a third position in which the secondary control member contacts the second side (<NUM>) of the orifice assembly (<NUM>) to restrict fluid flow along the fluid flow path.