Pressure loaded service regulator with pressure balanced trim

A gas regulator includes an actuator, a regulator valve, and pressure loading device. The pressure loading device provides a pressure load to a surface of a diaphragm of the actuator to act against a downstream pressure being applied to the opposite surface of the diaphragm and being controlled by the regulator. As the downstream pressure varies and the diaphragm displaces to move a control element to regulate the downstream pressure, the pressure loading device maintains a specified load pressure. The regulator may further include a balanced trim applying a balancing force to offset a force of an upstream pressure on the control element.

FIELD OF THE INVENTION

The present invention relates to fluid flow regulating devices such as gas regulators and, more particularly, to gas regulators having pressure loading devices as well as pressure balanced trim for regulating an outlet pressure proximate a predetermined setpoint pressure.

BACKGROUND

The pressure at which typical gas distribution systems supply gas may vary according to the demands placed on the system, the climate, the source of supply, and/or other factors. However, most end-user facilities equipped with gas appliances such as furnaces, ovens, etc., require the gas to be delivered in accordance with a predetermined pressure, and at or below a maximum capacity of a gas regulator. Therefore, gas regulators are implemented into these distribution systems to ensure that the delivered gas meets the requirements of the end-user facilities. Conventional gas regulators generally include a closed-loop control actuator for sensing and controlling the pressure of the delivered gas.

In addition to a closed loop control, some conventional gas regulators include a relief valve. The relief valve is adapted to provide over pressure protection when the regulator or some other component of the fluid distribution system fails, for example. Accordingly, in the event the delivery pressure rises above a predetermined threshold pressure, the relief valve opens to exhaust at least a portion of the gas to the atmosphere, thereby reducing the pressure in the system.

FIGS. 1 and 2depict one conventional gas regulator10. The regulator10generally comprises an actuator12and a regulator valve14. The regulator valve14defines an inlet16for receiving gas from a gas distribution system, for example, and an outlet18for delivering gas to an end-user facility such as a factory, a restaurant, an apartment building, etc. having one or more appliances, for example. Additionally, the regulator valve14includes a valve port20disposed between the inlet and the outlet. Gas must pass through the valve port20to travel between the inlet16and the outlet18of the regulator valve14.

The actuator12is coupled to the regulator valve14to ensure that the pressure at the outlet18of the regulator valve14, i.e., the outlet pressure, is in accordance with a desired outlet or control pressure. The actuator12is therefore in fluid communication with the regulator valve14via a valve mouth22and an actuator mouth24. The actuator12includes a control assembly26for sensing and regulating the outlet pressure of the regulator valve14. Specifically, the control assembly26includes a diaphragm28, a piston30, and a control arm32having a valve disc34. The conventional valve disc34includes a generally cylindrical body36and a sealing insert38fixed to the body36. The valve body36may also include a circumferential flange40integrally formed therewith, as depicted inFIG. 2. The diaphragm28senses the outlet pressure of the regulator valve14. The control assembly26further includes a control spring42in engagement with a top-side of the diaphragm28to offset the sensed outlet pressure. Accordingly, the desired outlet pressure, which may also be referred to as the control pressure, is set by the selection of the control spring42.

The diaphragm28is operably coupled to the control arm32, and therefore, the valve disc34via the piston30, controls the opening of the regulator valve14based on the sensed outlet pressure. For example, when an end user operates an appliance, such as a furnace, for example, that places a demand on the gas distribution system downstream of the regulator10, the outlet flow increases, thereby decreasing the outlet pressure. Accordingly, the diaphragm28senses this decreased outlet pressure. This allows the control spring42to expand and move the piston30and the right-side of the control arm32downward, relative to the orientation ofFIG. 1as shown inFIG. 2. This displacement of the control arm32moves the valve disc34away from the valve port20to open the regulator valve14.FIG. 2depicts the valve disc34in a normal, open operating position. So configured, the appliance may draw gas through the valve port20toward the outlet18of the regulator valve14.

In the conventional regulator10depicted inFIG. 1, the control assembly26further functions as a relief valve, as mentioned above. Specifically, the control assembly26also includes a relief spring44and a release valve46. The diaphragm28includes an opening48through a central portion thereof and the piston30includes a sealing cup50. The relief spring44is disposed between the piston30and the diaphragm28to bias the diaphragm28against the sealing cup50to close the opening48, during normal operation. Upon the occurrence of a failure such as a break in the control arm32, the control assembly26is no longer in direct control of the valve disc34and inlet flow will move the valve disc34will move into an extreme open position. This allows a maximum amount of gas to flow into the actuator12. Thus, as the gas fills the actuator12, pressure builds against the diaphragm28forcing the diaphragm28away from the sealing cup50, thereby exposing the opening48. The gas therefore flows through the opening48in the diaphragm28and toward the release valve46. The release valve46includes a valve plug52and a release spring54biasing the valve plug52into a closed position, as depicted inFIG. 2. Upon the pressure within the actuator12and adjacent the release valve46reaching a predetermined threshold pressure, the valve plug52displaces upward against the bias of the release spring54and opens, thereby exhausting gas into the atmosphere and reducing the pressure in the regulator10.

A regulator's performance is dictated by the volume of a fluid that can be transferred downstream while maintaining a designated outlet pressure. In the conventional regulator10, the control spring42inherently generates less force as it expands towards an uncompressed length when displacing the control arm32to open the valve port20. Additionally, as the control spring42expands, the diaphragm28deforms, which increases the area of the diaphragm28. The decreased force supplied by the control spring42and the increased area of the diaphragm28in this operational scenario combine to create a regulator response wherein the force provided by the control spring42cannot adequately balance the force generated by the diaphragm28thereby resulting in an outlet control pressure that is less than that originally set by the user. This phenomenon is known as “droop.” When “droop” occurs, the outlet pressure decreases below its set control pressure and the regulator10may not function as intended. As the outlet pressure decreases, the amount of fluid transferred while maintaining the outlet pressure range, also know as the rated flow value, is decreased. Consequently, a need exists for improving the performance of conventional regulators by reducing or eliminating the effects of “droop” on the regulator's ability to maintain the outlet control pressure at a desired setpoint pressure and to maximize the volume of fluid flowing through the regulator valve.

Another factor affecting the performance of the regulator10is the force of the upstream pressure on the valve disc34. When the actuator12is in the open position as shown inFIG. 2, the upstream pressure of the fluid passing through the valve port20applies a force on the valve disc34in the direction of the open position. Consequently, the magnitude of the upstream pressure and its fluctuations can affect the performance of the actuator12in maintaining the downstream pressure at the desired setpoint pressure. For example, as the upstream pressure increases, a greater downstream pressure is necessary to cause the actuator assembly26to move the valve disc34toward the valve port20to decrease the fluid flow through the valve14. The problem is heightened in regulators with larger port sizes that can experience higher inlet pressures. In some implementations, it is necessary to install regulators having lower rated capacities to avoid over pressurizing the downstream portion of the system. Consequently, a need further exists for gas regulators that are less sensitive to upstream pressure variations at the valve port.

SUMMARY OF THE INVENTION

In one aspect, the invention is directed to a fluid regulating device that may include a valve having a first inlet, a first outlet, and a first valve port disposed between the first inlet and the first outlet, and an actuator coupled to the valve. The actuator may include a housing coupled to the valve, a first valve disc disposed within the valve and adapted for displacement between a closed position engaging the first valve port and an open position disposed away from the first valve port, and a first diaphragm disposed within the housing and dividing the housing into a first cavity and a second cavity, with the first diaphragm being operatively coupled to the first valve disc, and with the first cavity of the housing being in fluid communication with the first outlet of the valve. The fluid regulating device may further include a pressure loading device coupled to the valve and to the actuator. The pressure loading device may include a body having a second inlet, a second outlet, and a second valve port disposed between the second inlet and the second outlet, wherein the second inlet is in fluid communication with the first inlet, and the second outlet is in fluid communication with the second cavity of the housing, a bonnet coupled to the body, a second valve disc disposed within the body and adapted for displacement between a closed position engaging the second valve port and an open position disposed away from the second valve port, a second diaphragm disposed within the bonnet and dividing the bonnet into a first cavity and a second cavity, with the second diaphragm being operatively coupled to the second valve disc, and with the first cavity of the bonnet being in fluid communication with the second outlet, and a control spring disposed within the second cavity of the bonnet and engaging the second diaphragm. The second diaphragm and the control spring may be configured to cause the second valve disc to move toward its open position when the pressure at the second outlet decreases and to cause the second valve disc to move toward its closed position when the pressure at the second outlet increases to maintain a pressure within the second cavity of the actuator approximately equal to a load pressure, and the actuator may be configured to cause the first valve disc to move toward its open position when the pressure at the first outlet decreases and to cause the first valve disc to move toward its closed position when the pressure at the first outlet increases to maintain the pressure at the first outlet approximately equal to a setpoint pressure.

In another aspect, the present invention is directed to a fluid regulating device having a valve and an actuator coupled to the valve, wherein the valve has a first inlet, a first outlet, and a first valve port disposed between the first inlet and the first outlet, and the actuator has a first valve disc adapted for displacement between a closed position engaging the first valve port and an open position disposed away from the first valve port, and a first diaphragm dividing the actuator into a first cavity and a second cavity with the first cavity being in fluid communication with the first outlet of the valve, wherein the first diaphragm is operatively coupled to the first valve disc to move the first valve disc between the open and closed positions. The improvement in the fluid regulating device may include a pressure loading device coupled to the valve and to the actuator, with the pressure loading device having a body having a second inlet, a second outlet, and a second valve port disposed between the second inlet and the second outlet, wherein the second inlet is in fluid communication with the first inlet, and the second outlet is in fluid communication with the second cavity of the actuator, a bonnet coupled to the body, a second valve disc disposed within the body and adapted for displacement between a closed position engaging the second valve port and an open position disposed away from the second valve port, a second diaphragm disposed within the bonnet and dividing the bonnet into a first cavity and a second cavity, with the second diaphragm being operatively coupled to the second valve disc, and with the first cavity of the bonnet being in fluid communication with the second outlet, and a control spring disposed within the second cavity of the bonnet and engaging the second diaphragm. The second diaphragm and the control spring may be configured to cause the second valve disc to move toward its open position when the pressure at the second outlet decreases and to cause the second valve disc to move toward its closed position when the pressure at the second outlet increases to maintain a pressure within the second cavity of the actuator approximately equal to a load pressure, and the actuator may be configured with the load pressure bearing upon the first diaphragm to cause the first valve disc to move toward its open position when the pressure at the first outlet decreases and to cause the first valve disc to move toward its closed position when the pressure at the first outlet increases to maintain the pressure at the first outlet approximately equal to a setpoint pressure.

In a further aspect, the invention is directed to a fluid regulating device that may include a valve having a first inlet, a first outlet, and a first valve port disposed between the first inlet and the first outlet, and an actuator coupled to the valve. The actuator may include a first valve disc disposed within the valve and adapted for displacement between a closed position engaging the first valve port and an open position disposed away from the first valve port, and a first diaphragm operatively coupled to the first valve disc to move the first valve disc between the open and closed positions, wherein a first surface of the first diaphragm is in fluid communication with the first outlet of the valve. The fluid regulating device may further include a pressure loading device coupled to the valve and to the actuator, and the pressure loading device may have a second inlet and a second outlet with the second inlet being in fluid communication with the first inlet, and the second outlet being in fluid communication with a second surface of the first diaphragm, where the pressure loading device is configured to increase a fluid flow through the pressure loading device when the pressure at the second outlet is less than a load pressure and a second valve port disposed between the second inlet and the second outlet. The second inlet may be in fluid communication with the first inlet, and the second outlet may be in fluid communication with the second cavity of the housing. The pressure loading device may be configured to increase a fluid flow through the device when the pressure at the second outlet decreases and to decrease a fluid flow through the device when the pressure at the second outlet increases to maintain a pressure against the second surface of the first diaphragm approximately equal to a load pressure, and the actuator may be configured to cause the first valve disc to move toward its open position when the pressure at the first outlet decreases and to cause the first valve disc to move toward its closed position when the pressure at the first outlet increases to maintain the pressure at the first outlet approximately equal to a setpoint pressure.

Additional aspects of the invention are defined by the claims of this patent.

DETAILED DESCRIPTION

FIGS. 3 and 4depict a gas regulator110constructed in accordance with one embodiment of the present invention. The gas regulator110generally comprises an actuator112and a regulator valve114. The regulator valve114includes an inlet116for receiving gas from a gas distribution system, for example, and an outlet118for delivering gas to a facility having one or more appliances, for example. The actuator112is coupled to the regulator valve114and includes a control assembly120having a control element, such as a valve disc122. During a first or normal operational mode, the control assembly120senses the pressure at the outlet118of the regulator valve114, i.e., the outlet pressure, and controls a position of the valve disc122such that the outlet pressure approximately equals a predetermined setpoint or control pressure.

With continued reference toFIG. 3, the regulator valve114defines a throat124and a valve mouth126. The throat124is disposed between the inlet116and the outlet118, and has a valve port128disposed therein. Gas must travel through the valve port128to travel between the inlet116and the outlet118of the regulator valve114. The valve port128is removable from the regulator valve114such that it may be replaced with a different valve port having a bore of a different diameter or configuration to tailor operational and flow characteristics of the regulator valve114to a specific application. In the disclosed embodiment, the valve mouth126defines an opening disposed along an axis that is generally perpendicular to an axis of the inlet116and outlet118of the regulator valve114.

The actuator112includes a housing130and the control assembly120, as mentioned above. The housing130includes an upper housing component130aand a lower housing component130bsecured together with a plurality of fasteners, for example. The lower housing component130bdefines a control cavity132and an actuator mouth134. The actuator mouth134is connected to the valve mouth126of the regulator valve114to provide fluid communication between the actuator112and the regulator valve114. The upper housing component130adefines a pressure loading cavity136and an inlet port138. The upper housing component130afurther defines a tower portion140for accommodating a portion of the control assembly120, as will be described.

The control assembly120includes a diaphragm subassembly142and a disc and balancing subassembly144. The diaphragm subassembly142includes a diaphragm148, a piston150, a pressure loading device152, a lock-up spring154, a lock-up spring seat156and a piston guide158. The pressure loading device152replaces the control spring42of the actuator12ofFIG. 1to apply a loading force to the diaphragm148in a manner discussed more fully below. However, while a control spring is not shown in the illustrated embodiment of the actuator112, pressure loaded regulators may be configured to implement control springs and pressure loads in conjunction within an actuator to regulate downstream pressures. The diaphragm148includes a disc-shaped diaphragm defining an opening through a central portion thereof. The diaphragm148is constructed of a flexible, substantially air-tight, material and its periphery is sealingly secured between the upper and lower housing components130a,130bof the housing130. The diaphragm148therefore separates the pressure loading cavity136from the control cavity132. A diaphragm head160is disposed on top of the diaphragm148and defines an opening disposed concentric with the opening in the diaphragm148. The diaphragm head160further defines a bleed hole162there through that functions to place the pressure loading cavity136in fluid communication with the control cavity132as will be discussed more fully below.

The piston150of the disclosed embodiment is a generally elongated rod-shaped member having a sealing cup portion164and a yoke166. The sealing cup portion164is concaved and generally disc-shaped and extends circumferentially about a mid-portion of the piston150, and is located just below the diaphragm148. The head160and the sealing cup164are secured to each other and/or the diaphragm148at the central opening to form a seal there between. The sealing cup164defines a second bleed hole168there through that cooperates with the bleed hole162to place the cavities132,136in fluid communication. The yoke166includes a cavity adapted to accommodate a coupler172which connects to a portion of the disc and balancing subassembly144to enable attachment between the diaphragm subassembly142and the disc and balancing subassembly144, as will be described.

The piston150extends upwardly through the openings in the diaphragm148and the diaphragm head160, respectively. The upwardly extending portion of the piston150is slidably disposed in a cavity in the piston guide158, which maintains the axial alignment of the piston150relative to the remainder of the control assembly120. The lock-up spring seat156is disposed at the upper end of the piston150, with the lock-up spring154being retained between the spring seat156and the piston guide158. The lock-up spring154, spring seat156and piston guide158are disposed within the tower portion140of the upper housing component130a. The piston guide158may be threaded into the tower portion140such that it may be rotated to move axially within the tower portion140to adjust the tension in the lock-up spring154. Alternatively or in addition, the top portion of the piston150may be threaded with the spring seat156being rotatably disposed thereon so that the spring seat156may be rotated on the piston150to adjust the tension of the lock-up spring154or removed to replace the spring154. The lock-up spring154is grounded against the piston guide158and applies an upward force to the spring seat156, which in turn is applied to the piston150to provide a biasing force in the direction of the closed or lock-up position of the regulator110as shown inFIG. 3.

Pressure supplied by the pressure loading device152acts against the pressure in the control cavity132, which is sensed by the diaphragm148. As stated, the pressure in the control cavity132is the same pressure as that which exists at the outlet118of the regulator valve114. Accordingly, the force supplied by the pressure loading device152sets the outlet pressure to a desired setpoint or control pressure for the regulator110. The details of the configuration and the operation of the pressure loading device152are discussed more fully below. It should be noted that the diaphragm148is installed upside down relative to the diaphragm28ofFIGS. 1 and 2because the load pressure will be equal to or greater than the control pressure and act to force the diaphragm148downward.

The diaphragm subassembly142is operably coupled to the disc and balancing subassembly144, as mentioned above, via the yoke166of the piston150and the coupler172, and by a control arm176. The disc and balancing subassembly144includes an actuator stem178that is engaged by the control arm176to move the valve disc122between the open and closed positions as the diaphragm148flexes due to variations in the downstream pressure. Specifically, the actuator stem178is a generally linear rod having an end surface engaged by the control arm176. The control arm176is a slightly curved rod and includes a fulcrum end176aand a free end176b. The fulcrum end176ais pivotally coupled to the lower housing component130band includes a finger180having a rounded end and engaging the end surface of the actuator stem178. The free end176bis received between a top portion172aand a pin172bof the coupler172that is attached to the yoke166of the piston150. Thus, the coupler172and the control arm176operably connect the disc and balancing subassembly144to the diaphragm subassembly142.

The valve disc122of the disc and balancing subassembly144is operatively connected to the actuator stem178, and includes an outer disc portion182and a coaxial inner disc portion184. The outer disc portion182includes a recess receiving a sealing insert186having a sealing surface that engages the outlet of the valve port128to cut off the fluid flow through the regulator valve114. The disc portions182,184are connected to the actuator stem178by balanced port stem188and a balancing spring seat190, and the combined elements are supported for linear movement by a stem guide192, a retainer plate194, a balancing diaphragm retainer196and a balancing port housing198. The stem guide192is configured to fit within the actuator mouth134, and includes a generally cylindrical inner portion that slidably retains the actuator stem178. The stem guide192further includes channels200therethrough forming a portion of the path placing the outlet118in fluid communication with control cavity132as discussed further below.

The stem guide192engages the retainer plate194, which is disposed between the stem guide192and balanced port housing198, to hold the retainer plate194and balanced port housing198in place within the valve mouth126. The retainer plate194is generally circular and includes a central opening through which the balanced port stem188passes. The balanced port housing198is generally cylindrical and hollow, extends toward the valve port128, and has an inner diameter sized to slidably receive the valve disc122. The diaphragm retainer196is disposed within the balanced port housing198and the opening of the retainer plate194, and is held in place between a surface of the retainer plate194and an inner shoulder of the balanced port housing198. A disc-shaped balancing diaphragm202having a central opening is provided within the balanced port housing198. The balancing diaphragm202is constructed of a flexible, substantially air-tight, material and its periphery is secured between the diaphragm retainer196and the balanced port housing198. The inner edge at the central opening of the balancing diaphragm202is sealingly secured between the valve disc122and the balanced port stem188. The valve disc122, balanced port stem188and the actuator stem178are biased toward the open position of the regulator valve114by a balancing spring204disposed between the spring seat190and a seating surface of the diaphragm retainer196.

The balancing diaphragm202provides a force on the valve disc122in the direction of the valve port118to compensate for the force applied to the valve disc122due to the upstream pressure of the fluid passing through the valve port118. The inner disc portion184has an outer diameter that is smaller than an inner diameter of the outer disc portion182to allow fluid to enter a passage206of the inner disc portion184and a corresponding passage208within the balanced port stem188. The passage208opens into the interior of the diaphragm retainer196thereby placing the surface of the balancing diaphragm202opposite the valve port118in fluid communication with the upstream pressure bearing on the valve disc122. The components of the disc and balancing subassembly144are configured so that the force applied by the balancing diaphragm202is approximately opposite and equal to the force of the upstream pressure on the valve disc122to eliminate any influence of the upstream pressure on the diaphragm subassembly142and thereby allowing for more accurate control of the downstream pressure by the gas regulator110.

Downstream pressure feedback is provided to the control cavity132of the actuator112via a Pitot tube210having a sensing point within the outlet118of the regulator valve114. The Pitot tube210extends into the valve mouth126and passes through openings through the balanced port housing198and the retainer plate194, respectively. The Pitot tube210provides the downstream pressure to the interior of the stem guide192, and to the control cavity132via the channels200of the stem guide192.

As discussed above, the pressure loading device152replaces the control spring in the actuator112in providing the force opposing the downstream pressure acting on the opposite side of the diaphragm148. In the illustrated embodiment, the pressure loading device152is provided in the form of a regulator configured to receive fluid at an inlet220having the upstream pressure and outputting fluid having a specified or desired load pressure at an outlet222. The inlet220and the outlet222are defined in a body224of the regulator152having a valve port226disposed between the inlet220and the outlet222. The inlet220receives fluid via an upstream pressure supply line228having an opposite end connected to an upstream pressure port230of the regulator valve114. The supply line228places the inlet220of the regulator152in fluid communication with the interior of the regulator valve114upstream of the valve port128. The upper housing component130aof the actuator112is modified from the housing of the actuator12to include the inlet load pressure port138opening into the relief cavity136and being connected to the outlet222of the regulator152via a conduit234to place the outlet222in fluid communication with the relief cavity136and corresponding surface of the diaphragm148.

A control assembly236is provided in the regulator152to ensure that the pressure at the outlet222of the regulator152, i.e., the load pressure, is in accordance with a desired load pressure necessary for the actuator112to maintain the setpoint downstream pressure. The control assembly236senses and regulates the load pressure of the regulator152. Specifically, the control assembly236includes a diaphragm238, a control spring240, and a control arm or valve stem242having a valve disc244. The conventional valve disc244includes a generally cylindrical body and a conical or frustoconical upper portion connected to the control arm242and sized to seat within an opening of the valve port226to allow or prevent fluid to pass through the valve body224. A valve spring246disposed between a bottom surface of the valve disc244and a seating surface of a valve retainer248biases the valve disc244toward the closed position as shown. The valve spring246allows the valve disc244to be displaced downward to unseat from the valve port226due to the force of the control spring240and allow fluid flow through the valve port226as discussed further below. The valve disc244, valve spring246and valve retainer248are retained within the body224upstream of the valve port226by a bottom plate250secured to a lower open end of the body224.

The regulator152further includes a bonnet252enclosing the diaphragm238and control spring240above an upper portion of the body224. The diaphragm238includes a disc-shaped diaphragm defining an opening through a central portion thereof. The diaphragm238is constructed of a flexible, substantially air-tight, material and its periphery is sealingly engaged between the bonnet252and the body224. The diaphragm238therefore separates a control cavity254of the regulator152from a bonnet cavity256containing the control spring240. A diaphragm head258and lower spring seat260are disposed on top of the diaphragm238and define openings disposed concentric with the opening in the diaphragm238. A pusher post262having a central hub and outwardly extending flange is disposed on the control cavity side of the diaphragm238, with the hub extending through the openings of the diaphragm238, head258and spring seat260. The pusher post262is secured in place by a retainer spring264pressed downwardly over the hub and against an upper surface of the spring seat260.

The control spring240is disposed between the lower spring seat260and an upper spring seat266, with the upper spring seat266compressing the control spring240against the lower spring seat260. An adjusting screw268is received through a threaded opening at the top of the bonnet252and engages a top surface of the upper spring seat266to retain the upper spring seat266in position within the bonnet252. Configured in this way, the control spring240is grounded against bonnet252and applies a downward force to the lower spring seat260and the diaphragm238. In the disclosed embodiment, the force generated by the control spring240is adjustable by turning the adjusting screw268to raise or lower the upper spring seat266. As the force of the control spring240is adjusted, the load pressure output by the regulator152to the actuator112is correspondingly adjusted.

The valve stem242and valve disc244are operatively coupled to the diaphragm238and the control spring240. The pusher post262includes a recess within the hub and facing the control cavity254and the valve port226. A soft seat272is disposed in the recess of the pusher post262and receives the end of the valve stem242opposite the valve disc244. Accordingly, the valve stem242and valve disc244move upwardly and downwardly as the diaphragm238flexes in response to changes in the load pressure. The upper portion of the valve port226downstream of the valve disc244includes a channel274passing therethrough and aligning with a corresponding opening of the body224to place the control cavity254and, correspondingly, the diaphragm238in fluid communication with the outlet222to allow the diaphragm238to sense the actual load pressure at the outlet222and within the relief cavity136of the actuator112.

FIG. 3depicts the regulator110of the present embodiment with the valve disc122within the valve body114and the valve disc244in their closed or lock-up positions. So configured, gas does not flow through either the valve port128of the regulator valve114or the valve port226of the pressure loading device152. This configuration is achieved within the regulator valve114because the outlet pressure, which corresponds to the pressure in the control cavity136of the housing126and sensed by the diaphragm146, is greater than the force applied by the load pressure from the pressure loading device152. Accordingly, the downstream pressure at the outlet118forces the diaphragm148and the piston150into the closed position. Similarly, the configuration is achieved within the pressure loading device152because the load pressure, which corresponds to the pressure in the control cavity154of the body224, plus the force of the valve spring246is greater than the force applied by the control spring240to the diaphragm23, and load pressure forces the diaphragm238and the valve disc244to the closed position. Once the actuator112and the pressure loading device152are closed, pressure will bleed through the bleed holes162,168until the load pressure and the outlet pressure equalize. When the pressure on both sides of the diaphragm148are equal, the lock-up spring154will bias the diaphragm assembly142upward to retain the valve disc122in the closed position.

When an operating demand is placed on the gas distribution system, e.g., a user begins operating an appliance such as a furnace, a stove, etc., the appliance draws gas from the outlet118and correspondingly the control cavity132of the actuator112, thereby reducing the pressure that is sensed by the diaphragm148. As the pressure sensed by the control cavity side of the diaphragm148decreases, a force imbalance occurs between a load pressure force and an outlet pressure force on the diaphragm148such that the load pressure overcomes the forces of the lock-up spring154and displaces the diaphragm148and piston150downward relative to the housing130as shown inFIG. 4. This causes the control arm176to pivot in the clockwise direction, which in turn rotates the finger180relative to the surface182of the actuator stem178. This allows the actuator stem178and the valve disc122to move away from the outlet124of the valve port128due to the force of the balancing spring200to open the regulator valve114.

As the diaphragm148displaces downwardly, the volume within the pressure loading cavity136increases, and the increased volume of the pressure loading cavity136along with the bleeding of gas into the control cavity132through the bleed holes162,168cause a corresponding drop in the load pressure within the cavity136. At the same time, the load pressure decrease causes a force imbalance to occur between the control spring force and the load pressure force on the diaphragm238of the pressure loading device152such that the control spring240expands and displaces the diaphragm238downward relative to the body224. The displacement of the diaphragm238forces the valve stem242and valve disc244downward and causes the valve disc244to become unseated and allow fluid to flow through the valve port226and into the relief cavity136of the actuator112. The fluid flowing into the relief cavity136increases the load pressure being applied to the diaphragm148so that the force applied to the diaphragm148does not decrease as is the case in the actuator112wherein the force applied by the control spring42decreases as the spring42expands to open the regulator valve14.

When the demand is removed from the gas distribution system, such as when the user shuts off the appliance, the regulator110initially responds by decreasing the fluid flow through the regulator valve114. As gas continues to flow through the valve port128and to the downstream portion of the system, the pressure increases at the outlet118and, correspondingly, in the control cavity132of the actuator112. As the pressure sensed by the diaphragm148increases and overcomes the load pressure force, the diaphragm148and piston150are forced upward relative to the housing130. The upward movement causes the control arm176to pivot in the counterclockwise direction, which in turn drives the actuator stem178and the valve disc122toward the valve port128to reduce the fluid flow through the regulator valve114. Under normal operating conditions, the outlet pressure will drop to approximately the actuator setpoint pressure and remain there until the downstream demand changes in a manner that causes a response from by the actuator112.

As the diaphragm148displaces upwardly, the volume within the pressure loading cavity136decreases, and the decreased volume of the pressure loading cavity136causes a corresponding increase in the load pressure within the pressure loading cavity136and within the control cavity254of the regulator152. The load pressure increase against the diaphragm238eventually overcomes the force of the control spring240, causing the diaphragm240to move upward. The upward movement of the diaphragm238allows the valve disc244to also move upwardly to reduce the fluid flow through the regulator152. Under normal operating conditions, the load pressure will equalize with the pressure in the control cavity132and remain there until the downstream demand changes in a manner that causes a response from by the actuator112and a corresponding response by the regulator152.

Several benefits may be derived from implementing pressure loading and balanced trim within a regulator as described above. For example, regulators in accordance with the present disclosure may be implemented in systems where higher inlet pressures are anticipated while maintaining a desired level of control and accuracy over the resulting downstream pressures. At higher inlet pressures, the force applied to the valve disc122by the balancing diaphragm increases corresponding to prevent influence on the control assembly120by the upstream pressures. The regulators may also be implemented where large upstream pressure variations are expected because the balanced trim substantially eliminates outlet pressure sensitivity to input pressure variations. Consequently, the balanced trim allows for higher rated capacities for the regulators and higher accuracy in the regulation of the downstream pressures by the regulator. Pressure loading also allows for a higher rated capacity for the regulator. The effects of “droop” on a regulator's ability to maintain the outlet control pressure at the desired setpoint pressure are reduced by the ability of the pressure loading device to maintain a more consistent load on the diaphragm of the regulator as compared to the variations in the amount of force and pressure provided by control springs. Moreover, the load consistency results in an increase in the accuracy of the control provided by the regulator.