Air spring pressure regulating valve

In some examples, a pressure regulating valve comprising a pressure chamber, a compressor configured to establish fluid communication with the pressure chamber, a vent valve configured to establish fluid communication with the pressure chamber, a pressure sensor, and a controller. The controller may determine a pressure based on the signal generated by the pressure sensor, and compare a pressure setpoint and the pressure. The controller may be configured to alter the pressure in the pressure chamber based on the comparison between the pressure setpoint and the pressure. For example, the controller may control the compressor to increase the pressure in the pressure chamber and/or control the vent vale to decrease the pressure in the pressure chamber. The altered pressure of the pressure chamber may generate movement of a restricting element within the pressure regulating valve.

TECHNICAL FIELD

The disclosure relates to pressure regulating valves.

BACKGROUND

Pressure regulating devices are frequently used in industrial and residential systems designed to deliver fluid flows to one or more gaseous or liquid fluid loads. The pressure regulating devices may be employed to deliver or maintain the delivered fluid within predetermined pressure parameters selected based on, for example, system integrity, process controls, various equipment restrictions, and/or other reasons. Pressure regulating devices may operate by sensing pressure fluctuations and making corrective adjustments around a pressure setpoint. Such pressure regulating devices may be employed within fluid delivery systems to maintain pressures downstream or upstream of the device.

SUMMARY

In examples described herein, a pressure regulating valve is configured to control a fluid pressure in a fluid circuit, such as piping header in a fluid distribution system, by at least controlling a pressure in a pressure chamber. The pressure regulating valve defines a flow area, through which fluid in the fluid circuit flows. A size of the flow area changes as a function of the pressure in the pressure chamber, and the size of the flow area affects the fluid pressure in the fluid circuit. Thus, the pressure regulating valve is configured to control the pressure in the fluid circuit by at least modifying the pressure in the pressure chamber. In some examples, the pressure regulating valve includes a controller configured to modify the pressure in the pressure chamber by at least controlling a compressor to increase the pressure in the pressure chamber and by at least controlling a vent valve to decrease the pressure in the pressure chamber. In some examples, increasing the pressure in the pressure chamber decreases the size of the flow area, which increases the fluid pressure through the valve, and decreasing the pressure in the pressure chamber increases the size of the flow area, which decreases the fluid pressure through the valve.

This disclosure also describes example techniques of using the pressure regulating valve to regulate a pressure.

Clause 1: A pressure regulating valve comprises a pressure chamber, a compressor configured to establish fluid communication with the pressure chamber, a vent valve configured to establish fluid communication with the pressure chamber, a pressure sensor configured to generate a signal indicative of a pressure, and a controller, the controller configured to determine a pressure setpoint for the pressure, determine the pressure based on the signal generated by the pressure sensor, compare the pressure setpoint and the pressure, and increase or decrease pressure in the pressure chamber based on the comparison of the pressure setpoint and the pressure, wherein the controller is configured to increase the pressure in the pressure chamber by at least controlling the compressor to increase pressure in the pressure chamber, and wherein the controller is configured to decrease the pressure in the pressure chamber by at least controlling the vent valve to decrease pressure in the pressure chamber.

Clause 2: The pressure regulating valve of clause 1, further comprising a restricting element and a sensing element in fluid communication with the pressure chamber, wherein the sensing element is configured to position in response to the pressure in the pressure chamber, and wherein the sensing element is configured to influence a position of the restricting element.

Clause 3: The pressure regulating valve of clause 1 or 2, wherein the restricting element comprises a valve disc, and wherein the pressure regulating valve further comprises a valve stem attached to the valve disc, a valve seat, and a flow area between the valve disc and the valve seat, wherein the sensing element is configured to translate the valve stem and alter the flow area in response to the controller increasing or decreasing pressure in the pressure chamber.

Clause 4: The pressure regulating valve of any of clauses 1 to 3, wherein the sensing element is configured to translate the valve stem and reduce the flow area in response to the controller increasing pressure in the pressure chamber, and wherein the sensing element is configured to translate the valve stem and increase the flow area in response to the controller decreasing pressure in the pressure chamber.

Clause 5: The pressure regulating valve of any of clauses 1 to 3, wherein the sensing element is configured to translate the valve stem and increase the flow area in response to the controller increasing pressure in the pressure chamber, and wherein the sensing element is configured to translate the valve stem and decrease the flow area in response to the controller decreasing pressure in the pressure chamber.

Clause 6: The pressure regulating valve of any of clauses 1 to 5 further comprising a spring element configured to translate the valve stem and reduce the flow area.

Clause 7: The pressure regulating valve of any of clauses 1 to 6 further comprising a valve inlet and a valve outlet, wherein the pressure regulating valve is configured to fluidly isolate the pressure chamber from the valve inlet and the valve outlet.

Clause 8: The pressure regulating valve of any of clauses 1 to 7 wherein the controller comprises a Proportional-Integral-Derivative (PID) controller, wherein the PID controller is configured to compare the pressure setpoint and the pressure, and use the pressure as a process variable.

Clause 9: The pressure regulating valve of any of clauses 1-8 wherein the controller is configured to receive a communication signal, and determine the pressure setpoint by at least associating the communication signal with a specific pressure.

Clause 10: The pressure regulating valve of any of clauses 1-9, wherein the controller is configured to receive a fluid leak signal, and increase or decrease the pressure in the pressure chamber to cause the sensing element to influence the restricting element to reduce or cease a flow through the pressure regulating valve in response to receiving the fluid leak signal.

Clause 11: The pressure regulating valve of any of clauses 1-11, wherein the wherein the pressure regulating valve comprises at least one of a poppet valve, a needle valve, a gate valve, a globe valve, a double-ported valve, or a spool valve.

Clause 12: A pressure regulating system comprising a valve comprising a pressure chamber, a valve inlet, a valve outlet, a sensing element in fluid communication with the pressure chamber, wherein the sensing element is configured to displace when a pressure in the pressure chamber increases or decreases, and a restricting element mechanically coupled to the sensing element, wherein the restricting element is configured to alter a flow area between the valve inlet and the valve outlet when the sensing element displaces, and a controller configured to determine a pressure setpoint, receive a signal indicative of a pressure, compare the pressure setpoint and the signal indicative of the pressure, control, based on the comparison, a compressor to increase the pressure in the pressure chamber and displace the sensing element and cause the restricting element to alter the flow area, and control, based on the comparison, a vent valve to decrease the pressure in the pressure chamber and displace the sensing element and cause the restricting element to alter the flow area.

Clause 13: The pressure regulating system of clause 12, wherein the sensing element comprises a diaphragm, a piston, or a diaphragm and a piston.

Clause 14: The pressure regulating system of clause 12 or 13, wherein the pressure comprises the pressure at the valve inlet, the system further comprising a pressure sensor configured to generate the signal indicative of the pressure at the valve inlet.

Clause 15: The pressure regulating system of any of clauses 12 through 14, further comprising a main valve comprising a main valve stem, wherein the valve is a pilot valve configured to control a position of the main valve stem.

Clause 16: The pressure regulating system of any of clauses 12 through 15, wherein the restricting element comprises a valve disc, and wherein the valve further comprises a valve stem mechanically coupling the valve disc to the sensing element, wherein the valve disc is configured to alter the flow area between the valve inlet and the valve outlet when the sensing element displaces.

Clause 17: The pressure regulating system of any of clauses 12 through 16, further comprising the compressor, the vent valve, and a pressure sensor configured to generate the signal indicative of the pressure at the valve inlet.

Clause 18: A method of regulating a pressure, the method comprising receiving, by a controller, a pressure signal indicative of a pressure, determining, by the controller, the pressure based on the signal, determining, by the controller, a pressure offset between the pressure and a pressure setpoint, altering, by the controller, a pressure in a pressure chamber of a pressure regulating valve based on the pressure offset by at least one of causing a compressor to increase the pressure in the pressure chamber, or causing a vent valve to vent the pressure chamber and decrease the pressure in the pressure chamber, wherein the altered pressure generates movement of a sensing element in fluid communication with the pressure chamber, and wherein the movement of the sensing element alters a flow area between a valve inlet and a valve outlet.

Clause 19: The method of clause 18, wherein receiving the pressure signal comprises receiving, by the controller, the pressure signal from a pressure sensor, wherein the pressure signal is indicative of a pressure at the valve inlet.

Clause 20: The method of clause 18 or 19, wherein movement of the sensing element alters the flow area by at least causing a restricting element to translate a valve stem and a valve disc, wherein the valve disc is in fluid communication with the flow area.

DETAILED DESCRIPTION

Pressure regulating valves are used in industrial and residential applications to control a pressure of a fluid in a fluid circuit. In some example systems, pressure regulating valves are situated between a main, higher pressure circuit and one or more branch, lower pressure circuits. The pressure regulating valve so situated may manipulate fluid flows provided from the main circuit in order to compensate for increases or decreases in demand by the one or more branch circuits, increases in the pressure of the main circuit (e.g., a back-pressure regulator), or some other load disturbance or combination of load disturbances.

For example, in some water distribution systems, pressure regulating valves may be used between a pumping station and a piping network serving consumers, in order to maintain a substantially constant water pressure in the piping network as demand among consumers fluctuates. As another example, in some natural gas delivery systems, pressure regulating valves may be used to reduce gas pressure from transmission pipelines to a distribution tap serving farm for a community. Within industrial settings such as chemical processing plants, oil refineries, and the like, pressure regulating valves may be used between multiple primary and secondary branch circuits in order to control various processes involving the precise control of one or more fluids, or to provide relatively steady-state pressures to, for example, air or water service branches which experience unpredictable, transitory demands. Because many end-user fluid demands require the fluid to be delivered to a secondary branch or maintained in a main branch in accordance with predetermined pressure parameters, pressure regulating valves are often employed to substantially maintain downstream or upstream pressures.

In examples described herein, a pressure regulating valve (PRV) is configured to allow a flow of the fluid through the pressure regulating valve in order to substantially maintain the pressure at or near a pressure setpoint either upstream or downstream of the pressure regulating valve. For example, for downstream pressure control, the PRV may be configured to receive a higher pressure fluid at an inlet of the pressure regulating valve, reduce the pressure of the fluid as it flows through the valve using a restricting element (e.g., a valve disc), and provide a reduced pressure fluid to a fluid circuit in fluid communication with the pressure regulating valve outlet. The PRV may be configured such that the amount of pressure reduction caused by the restricting element is variable, based on a pressure setpoint. For upstream pressure control, the PRV may be configured to receive a fluid at an inlet of the pressure regulating valve from a fluid circuit and reduce the pressure of the fluid circuit by at least providing a fluid discharge path from the fluid circuit. The flow area of the fluid discharge path may be controlled by a restricting element. The pressure regulating valve may be configured such that the amount of fluid discharged is dependent in part on a position of the restricting element, and the position of the restricting element may be variable and based on a pressure setpoint.

In examples described herein, a PRV is configured to control a fluid pressure in a fluid circuit by at least controlling a pressure in a pressure chamber, which affects the size of an area through which fluid flows through the pressure regulating valve. This area may be referred to herein as a flow area. The size (e.g., volume) of the flow area affects the fluid pressure in the fluid circuit. Thus, the PRV is configured to control the pressure in the fluid circuit by at least modifying the pressure in the pressure chamber. In some examples, the PRV includes a controller configured to modify the pressure in the pressure chamber by at least controlling a compressor to increase the pressure in the pressure chamber and by at least controlling a vent valve to decrease the pressure in the pressure chamber. In some examples, increasing the pressure in the pressure chamber decreases the size of the flow area, which increases the fluid pressure through the PRV, and decreasing the pressure in the pressure chamber increases the size of the flow area, which decreases the fluid pressure through the PRV.

In some cases, the PRV may be a normally open valve employed to substantially maintain a downstream pressure. The PRV may be configured to operate toward or into a closed position (e.g., by at least decreasing the volume of the flow area) as the downstream pressure increases, and operate toward or into an open position (e.g., by at least increasing the volume of the flow area) as the downstream pressure decreases. In this manner, the PRV may be configured to respond to downstream pressure. Decreasing downstream pressures may be indicative of an increase in demand, prompting the PRV to operate toward or into an open position to allow more flow to a downstream branch circuit. On the other hand, increasing downstream pressures may be indicative of a decrease in demand, prompting the PRV to operate toward or into a closed position to provide less flow to the downstream branch circuit. By treating downstream pressure as a proxy for demand in this manner, the PRV may substantially match the fluid supply from a main circuit to the fluid demand generated in the branch circuit, while substantially maintaining a set pressure downstream of the PRV.

In some cases, the PRV may be a normally closed valve employed to substantially maintain an upstream pressure (e.g., a back-pressure regulator (BPR)). The PRV may be configured to travel in an opening direction as the upstream pressure increases, and travel in a closing direction (or remain closed) as the upstream pressure decreases. Increasing upstream pressure may prompt the PRV to travel in the open direction, in order to allow increased flow through the flow area and decrease the upstream pressure. Decreasing downstream pressures may prompt the PRV to travel in the closing direction (or remain closed), in order to decrease flow through the flow area (or maintain substantially no flow) and increase the upstream pressure. In this manner, the PRV may be configured to substantially maintain pressure in an upstream supply branch while substantially matching demand from fluid loads drawing from the supply branch.

Some PRVs include a restricting element configured to help control flow from a higher pressure main circuit to a lower pressure branch circuit. The restricting element may comprise a valve member serving as a movable obstruction within a flow area of the PRV valve. The restricting element may comprise a valve disc, a valve spool, and/or some other movable obstruction which acts in combination with other components of the valve to provide a flow area. A fluid flowing through the PRV experiences a pressure decrease (e.g., head loss) as it proceeds through the PRV flow area due at least in part to the obstructing restricting element. The PRV may translate the restricting element to alter the spatial and/or obstruction characteristics of the flow area, which may alter the pressure loss experienced by the fluid as it travels through the PRV. Control of this pressure drop through the PRV allows control of a downstream or upstream pressure when the pressure regulating valve bridges a higher pressure main circuit and a lower pressure branch circuit. The restricting element generating the fluid pressure loss may be, for example, a poppet valve, a needle valve, a gate valve, a globe valve, spool valve, or some other mechanism or combination of mechanisms. The restricting element may be a double-ported valve.

A PRV may further include a sensing element configured to translate the restricting element, in order to vary a pressure drop and/or a flow area as a fluid flows through the pressure regulating valve. The sensing element may be, for example, a diaphragm or piston mechanically coupled to the restricting element, such that movement of the diaphragm or piston generates a translation of the restricting element. The PRV may be configured such that changes in an upstream or downstream pressure cause the sensing element to influence the restricting element and alter the flow area of the pressure regulating in a specific manner. For example, the PRV may be configured such that, when downstream pressure increases, the sensing element translates the restricting element to decrease the flow area of the PRV and consequently increase the pressure loss of a fluid flowing through the flow area, in order to cause a decrease in the downstream pressure. The PRV may be configured such that, when downstream pressure decreases, the sensing element translates the restricting element to increase the flow area of the PRV and consequently decrease the pressure loss of a fluid flowing through the flow area, in order to cause an increase in the downstream pressure. In some examples—such as when the PRV acts as a BPR—the PRV may be configured such that when an upstream pressure increases, the sensing element translates the restricting element to increase the flow area of the PRV and consequently decrease the upstream pressure.

In some examples, the degree of movement of the sensing element in response to changes in the upstream of downstream pressure may be influenced by a dome having a pressure chamber. The pressure chamber may hold a gas at a specific gas pressure, and be configured such that the gas pressure acts on one side of the sensing element. Adjustments to the gas pressure alter the degree of movement the sensing element experiences in response to changes in an upstream or downstream pressure, and allows the PRV to control the pressure setpoint around which the PRV operates. The PRV may include a compressor in fluid communication with the pressure chamber to increase a pressure in the pressure chamber, and may include a vent valve in fluid communication with the pressure chamber to decrease a pressure in the pressure chamber. The PRV may include a controller configured to cause the compressor and/or the vent valve to adjust the pressure in the pressure chamber, to enable the controller to direct changes in setpoint pressures.

In some examples, the PRV may be configured to receive a fluid flow from an upstream fluid branch and provide the fluid flow to a downstream branch while substantially maintaining a pressure in a downstream branch based on a current pressure setpoint. Thus, in some examples, in response to receiving a revised pressure setpoint less than the current pressure setpoint, the controller of the PRV may decrease the downstream pressure by at least controlling the compressor or the vent valve to modify the pressure in the pressure chamber in order to translate the restricting element to increase a pressure loss of the fluid flowing through the valve to the downstream branch (e.g., translate the restricting element in a closing direction). In addition, in response to receiving a revised pressure setpoint greater than the current pressure setpoint, the controller is configured to increase the downstream pressure by at least controlling the compressor or the vent valve to modify the pressure in the pressure chamber to translate the restricting element to decrease a pressure loss of the fluid flowing through the valve to the downstream branch (e.g., translate the restricting element in an opening direction).

In some examples, the PRV may be configured to act as a back-pressure regulator and substantially maintain a pressure in fluid branch upstream of the PRV based on a current pressure setpoint. Thus, in some examples, in response to receiving a revised pressure setpoint less than the current pressure setpoint, the controller of the PRV decreases the upstream pressure by at least controlling the compressor or the vent valve to modify the pressure in the pressure chamber in order to translate the restricting element to increase the flow area of the PRV and increase the flow from the upstream branch. In addition, in response to receiving a revised pressure setpoint greater than the current pressure setpoint, the controller of the PRV decreases the upstream pressure by at least controlling the compressor or the vent valve to modify the pressure in the pressure chamber in order to translate the restricting element to decrease the flow area of the PRV and decrease or even cease (in some examples) flow from the upstream branch.

In some examples, a PRV may be configured to operate around a specific pressure setpoint. The PRV may be configured to substantially maintain a setpoint pressure in a fluid branch downstream of the PRV, or may be configured to substantially maintain a setpoint pressure in a fluid branch upstream of the PRV, such as with the aid of a sensing element and a restricting element.

Here and elsewhere, “downstream” means the direction of a fluid flowing from a higher pressure area to a lower pressure area. “Upstream” denotes a direction opposite the downstream direction. For example, when a PRV is configured to provide flow from a higher pressure main circuit to a lower pressure branch circuit, a fluid flowing from the higher pressure main circuit to the lower pressure branch circuit flows in the downstream direction. The direction opposite the direction of fluid flow from the higher pressure main circuit to the lower pressure branch circuit is the upstream direction.

FIG. 1illustrates an example fluid system100including a main circuit102configured to provide a fluid (gas or liquid) to branch circuits108,118, and128. Branch circuit108is configured to be supplied with a fluid from main circuit102via PRV104, and configured to provide the fluid to fluid load110. PRV104is configured to receive higher pressure fluid from, for example, main circuit102, and supply the fluid at a lower pressure to branch circuit108. Branch circuit108is configured to provide the lower pressure fluid to fluid load110.

Fluid load110may be a load intended to receive fluid at some secondary pressure below the supply pressure of the fluid provided by main circuit102. For example, fluid load110might be a water or air connection intended to operate under relatively constant or transitory demand, where equipment and/or safety considerations require that the air or water be provided at a lower pressure than that present within main circuit102. Fluid load110might be, for example, a primary residential water connection, a water supply to a specific household appliance such as a water heater, a service air connection for the operation of air-driven tools, a pneumatic supply to some pneumatically operated system, a cooling water supply to specific equipment, or some other load intended to operate at pressures lower than that supplied by main circuit102.

PRV104is configured to receive the higher pressure fluid from main circuit102and provide the fluid at a lower pressure to branch circuit108. PRV104is configured to operate in accordance with a specific pressure setpoint, in order to maintain a substantially constant secondary pressure in branch circuit108as the main supply pressure of main circuit102varies and/or the fluid demand from fluid load110varies. For example, PRV104may be configured to maintain a secondary pressure in branch circuit108within 1% to about 30% of a setpoint pressure, such as within 30% of the pressure setpoint, within 20% of the pressure setpoint, within 10% of the setpoint pressure, within 5% of the setpoint pressure, or within 1% of the setpoint pressure.

PRV104may comprise a gas loaded, spring loaded, or gas and spring loaded dome, such as dome105. Dome105may impart a pressure and/or force to a sensing element (not shown inFIG. 1) within PRV104. The sensing element may be configured such that some portion of the fluid flow proceeding through PRV104imparts a pressure generally counter-acting the pressure and/or force imparted by dome105. The sensing element may be configured to translate in response to changes in the dome pressure and/or force, changes in the counter-acting pressure of the fluid flow through PRV104, or changes to both. The translation of the sensing element may alter the fluid flow characteristics of the flow through PRV104, and act to increase or decrease a pressure of branch circuit108. Dome105may be configured such that the pressure and/or force imparted by dome105is adjustable. Adjustments to the pressure and/or force imparted by dome105may thus be utilized as a control for the pressure setpoint of branch circuit108. For example, the force applied by dome105is configured to be adjusted by increasing or decreasing a gas pressure with a pressure chamber comprising dome105. As discussed below, in some examples, PRV104includes a compressor and a vent valve, and a controller of PRV104is configured to control the compressor to increase a gas pressure in the pressure chamber of dome105, and control a vent valve to reduce a gas pressure in the pressure chamber of dome105. The controller of a PRV, as described herein, can be located within a housing of the PRV or can be separate from the housing of the PRV. For example, the controller of PRV104can be located within a housing of PRV104or be positioned elsewhere within system100. Further, although controllers of individual PRVs of system100are described herein, in some examples, one controller can control multiple PRVs. That is, system100can include one or more controllers configured to provide the control of PRVs described herein.

Pressure sensor106is configured to provide an indication of a pressure at a location within branch circuit108, a pressure at an outlet of PRV104, or a pressure at some other location in fluid communication with branch circuit108. For example, pressure sensor106, as well as other pressure sensors described herein, can include any suitable pressure sensing circuitry and other structure configured to generate a signal indicative of the pressure at the sensing location. In some examples, a controller (e.g., of PRV104) can adjust the dome105of PRV104based on the indication provided by pressure sensor106. For example, pressure sensor106may indicate a first pressure of branch circuit108. In order to substantially establish a second (higher or lower) pressure in branch circuit108, the controller can adjust the gas pressure within a pressure chamber comprising dome105until pressure sensor106substantially indicates the second pressure.

System100may include additional branch circuits, such as branch circuit118. Branch circuit118is configured to receive fluid from main circuit102via PRV114and provide fluid to fluid load120. PRV114and fluid load120may be similar to PRV104and fluid load110. For example, fluid load120may be a load intended to receive fluid at some particular pressure below the supply pressure of the fluid provided by main circuit102, and PRV114may be configured to substantially maintain the particular pressure in branch circuit118. The particular pressure based on fluid load120may be greater, less than, or equal to the predetermined pressure based on fluid load110. Correspondingly, a particular pressure setpoint of PRV114may be greater, less than, or equal to the specific pressure setpoint of PRV104. PRV114may be configured to operate similarly to PRV104, such that PRV114may substantially maintain the particular pressure within branch circuit118as the main supply pressure of main circuit102and/or the fluid demand from fluid load120varies. PRV114may comprise dome115, and pressure sensor116, which is configured to generate an indication of a pressure at a location within branch circuit118, a pressure at an outlet of PRV114, or a pressure at some other location in fluid communication with branch circuit118.

System100may further include a branch circuit128. Branch circuit128may receive fluid from main circuit102via PRV124. PRV124may be configured to operate similarly to PRV104and PRV114, such that PRV124may substantially maintain an established pressure within branch circuit128as the main supply pressure of main circuit102and/or downstream fluid demands vary. PRV124may comprise dome125, and pressure sensor126, which is configured to generate an indication of a pressure at a location within branch circuit128, a pressure at an outlet of PRV124, or a pressure at some other location in fluid communication with branch circuit128.

PRV124may act as a primary pressure regulator and provide fluid at an established pressure to secondary pressure regulator130, secondary pressure regulator136, and secondary pressure regulator142. Secondary pressure regulator130may be configured to further reduce the pressure of the fluid within branch circuit128and provide fluid to tertiary branch132and fluid load134. Secondary pressure regulator136may be configured to further reduce the pressure of the fluid within branch circuit128and provide the fluid to tertiary branch138and fluid load140. Secondary pressure regulator142may be configured to further reduce the pressure of the fluid within branch circuit128and provide the fluid to tertiary branch144and fluid load146. Fluid load134, fluid load140, and fluid load146may require fluid supplied at pressures less than fluid load110and/or fluid load120, and secondary regulator130, secondary regulator136, and secondary regulator142may be provided in order accomplish the additional pressure reduction in a more accurate manner based on, for example, a droop or other inaccuracy which may occur during operation of PRV124. For example, PRV124might be used to reduce a main supply pressure of about 500 psi (4.35 megapascal) in main circuit102to a secondary pressure of about 100 psi (689 kilopascal (kPa)) in branch circuit128, and secondary pressure regulators130,136,142might be used to reduce the secondary pressure of about 100 psi (689 kPa) in branch circuit128to a pressure less than about 25 psi (172 kPa).

In some examples, system100includes one or more additional PRVs, such as PRV150, to act as a back-pressure regulator and operate in accordance with a specific pressure setpoint, in order to maintain a substantially constant main supply pressure of main circuit102as the fluid demands of PRV104, PRV114, and PRV124vary. PRV150may be configured to provide a relieving flow from main circuit102via, for example, fluid conduit164when a pressure of main circuit102exceeds a pressure setpoint. For example, PRV150may be configured to open or further open when the main supply pressure of main circuit102equals or exceeds a setpoint value, in order to provide a relieving flow from main circuit102via fluid conduit164. PRV150may be configured to close when the main supply pressure of main circuit102equals or is below the setpoint valve, and/or further close as the main supply pressure of main circuit102approaches the setpoint value from an over pressure condition in main circuit102.

In some examples, PRV150comprises a gas loaded, spring loaded, or gas and spring loaded dome, such as dome151. Dome151may impart a pressure and/or force to a sensing element (not shown) within PRV150. The sensing element may be configured such that the pressure of main circuit102(upstream of PRV150) counter-acts the pressure and/or force imparted by dome151. The sensing element may be configured to translate in response to changes in the dome pressure and/or force, changes in the pressure of main circuit102, or changes to both. PRV150may be configured such that the pressure and/or force imparted by dome151is adjustable. Adjustments to the pressure and/or force imparted by dome151may thus be utilized as a control for the pressure setpoint of branch circuit108. For example, a controller, e.g., of PRV150, can adjust a pressure provided by dome151by increasing or decreasing a gas pressure with a pressure chamber comprising dome151.

Pressure sensor152is configured to generate an indication of a pressure at a location within main circuit102, a pressure at an inlet of PRV151, or a pressure at some other location in fluid communication with main circuit102. The controller can adjust dome151of PRV150based on the indication provided by pressure sensor152. For example, pressure sensor152may indicate a first pressure of main circuit102. In order to substantially establish a second (higher or lower) pressure in main circuit102, the controller can adjust a gas pressure within a pressure chamber comprising dome151until pressure sensor152substantially indicates the second pressure.

As discussed, pressure regulating valves such as some or all of PRV104, PRV114, PRV124, PRV130, PRV136, PRV142, and PRV150may include a respective restricting element in order to control flow from a higher pressure main circuit such as main circuit102to a lower pressure branch circuit or fluid conduit. The restricting element may comprise a valve member serving as a movable obstruction within a flow area of the PRV. The restricting element may comprise a valve disc, a valve spool, and/or some other movable obstruction which acts in combination with other components of the PRV to provide the flow area. A fluid flowing through the PRV from a PRV inlet to a PRV outlet experiences a pressure decrease (e.g., head loss) as it proceeds through the flow area, due at least in part to the obstruction in the flow area provided by the restricting element. Movement of the restricting element, which can be referred to herein as PRV travel in some examples, may alter the obstruction provided by the restricting element, which may alter the pressure loss experienced by the fluid as it travels through the pressure regulating valve. The alteration of the restricting element may include a restricting element position corresponding to fully open, fully closed, and/or any position between fully open and fully closed. Control of the pressure drop through the valve using the restricting element allows control of a downstream or upstream pressure when the pressure regulating valve bridges a higher pressure main circuit and a lower pressure branch circuit.

Although PRVs104,114,124,130,136,142,150, are shown inFIG. 1, system100may include any suitable number of pressure regulating valves, and any number of main, branch, or otherwise designated fluid branches. The pressure regulating valves may be configured to receive a higher pressure fluid from a first branch and provide fluid to a second branch while substantially maintaining a pressure in the second branch. In some examples, some or all of the PRVs may be configured to as a back-pressure regulator and discharge fluid from a first branch to a second branch and/or fluid path to substantially maintain a pressure in the first branch. A PRV may supply any number of fluid loads and any number of fluid branches. For example, PRV104may supply one or more fluid loads in addition to fluid load110and one or more fluid branches in addition to branch circuit108. A main, branch, or otherwise designated fluid branch may receive fluid from any number of upstream pressure regulating valves. Any number of pressure regulating valves may operate in in series or in parallel with any quantity of pressure regulating valves.

FIG. 2illustrates an example PRV200. PRV200comprises PRV inlet224and PRV outlet226and is configured to provide a flow path for a fluid between PRV inlet224and PRV outlet226. In some examples, PRV200is configured to receive a higher pressure fluid at PRV inlet224and regulate the fluid flow in order to provide fluid at a lower pressure at PRV outlet226. For example, PRV200may be configured receive a higher pressure fluid from main circuit102and provide a lower pressure fluid to branch circuit108, branch circuit118, or branch circuit128(FIG. 1). Thus, PRV200is an example of any of the PRVs described with reference toFIG. 1(e.g., PRV104, PRV114, PRV124, PRV130, PRV136, PRV142, and/or PRV150)

The flow path between PRV inlet224and PRV outlet226may include a flow area222within PRV200, with a geometry of flow area222dependent in part on a restricting element204. Restricting element204may comprise, for example, valve stem218mechanically coupled to valve disc216. Flow area222is defined by any suitable structures. In some examples, as shown inFIG. 2, flow area222is at least partially bounded by valve disc216and valve seat220. PRV200is configured to allow for restricting element204to translate and alter flow area222. The alteration of flow area222may alter a pressure drop a fluid flow experiences between PRV inlet224and PRV outlet226, allowing for the regulation of a fluid flow between PRV inlet224and PRV outlet226.

PRV200further includes a sensing element206. Sensing element206is configured to influence the translation of restricting element204. For example, sensing element206may be mechanically coupled to restricting element204. Sensing element206includes a first side240and a second side242, and may be configured such that sensing element206experiences motion based on a differential pressure between first side240and second side242. The differential pressure may arise from a first pressure acting on first side240and a second side acting on second side242. For example, sensing element206may comprise a diaphragm or a piston having a first side and a second side. Sensing element206may define a perimeter244surrounding a portion of sensing element206. Sensing element206may be mechanically coupled and/or fixably attached to housing230of PRV200around all or some part of perimeter244. For example, sensing element206may be a particular diaphragm defining a perimeter244and fixably attached around the entirety of perimeter244. Sensing element may be a piston with perimeter244slidably translatable over some portion of housing230.

In some examples, sensing element206provides a substantially pressure-tight barrier between pressure chamber202of PRV200and some other portion of PRV200, where the other portion of PRV200is configured to experience a pressure dependent on a fluid flow through PRV200. For example, sensing element206may provide a provide a substantially pressure-tight barrier between pressure chamber202and some portion of PRV200between and including flow area222and PRV outlet226. Sensing element206may be configured to respond (e.g., by deflection of the diaphragm, or translation of the piston) based on a differential pressure between the pressure chamber and the portion of PRV200.

As discussed, the differential pressure across sensing element206may arise from a first pressure acting on first side240and a second pressure acting on second side242. In some examples, the first pressure acting on first side240of sensing element206may arise from a gas pressure within a pressure chamber202of PRV200and the second pressure acting on second side242of sensing element206may arise from a fluid flow through PRV200. For example, the second pressure may arise from fluid communication with one or more flow sections of a fluid flow between and including flow area222and PRV outlet226, where the one or more flow sections are separated from pressure chamber202by the substantially pressure-tight barrier provided by sensing element206. The second pressure may arise from flow sections which encounter second side242of sensing element206, as well as from flow sections which encounter valve disc216. Hence, in some examples, the differential pressure experienced across sensing element206is dependent on both a gas pressure within pressure chamber202and the fluid flow pressure at one or more flow sections of a fluid flowing from flow area222in the direction of PRV outlet226.

In some examples, PRV200is configured to adjust flow area222(in response to changes in a downstream pressure. Adjusting flow area222adjusts a pressure drop of fluid flow through flow area222. “Adjustment” to flow area222can refer to the adjustment to a size of flow area, such as an adjustment to a volume of flow area222. The downstream pressure may be a pressure at PRV outlet226, or some other flow section downstream of flow area222. For example, with a substantially constant gas pressure in pressure chamber202, an increase in the downstream pressure may increase the second pressure acting on second side242, and cause sensing element206to reposition restricting element204in a manner that increases a pressure drop of a fluid as it flows through flow area222(e.g., sensing element206may reposition restricting element204in a closing direction such as D2 to decrease flow area222). The increased pressure loss through flow area222may cause a decrease in the downstream pressure at, for example, PRV outlet226, or some other flow section downstream of flow area222.

Alternatively, with a substantially constant gas pressure in pressure chamber202, a decrease in downstream pressure may decrease the second pressure acting on second side242, and cause sensing element206to reposition restricting element204in a manner that decreases a pressure drop of a fluid as it flows through flow area222(e.g., sensing element206may reposition restricting element204in an opening direction such as D1 to increase flow area222). The decreased pressure loss through flow area222may cause an increase in the downstream pressure at, for example, PRV outlet226, or some other flow section downstream of flow area222. Hence, the differential pressure experienced across sensing element206, and the subsequent response of PRV200, may be dependent on both a gas pressure within pressure chamber202and a fluid flow pressure at one or more flow sections downstream of flow area222.

By adjusting the gas pressure in pressure chamber202(i.e., the first pressure acting on first side240of sensing element206), PRV200may be configured such that sensing element206operates around a specific pressure setpoint. Increases in downstream pressure above the setpoint may cause sensing element206to translate restricting element204to decrease flow area222and decrease the downstream pressure. Decreases in downstream pressure below the setpoint may cause sensing element206to translate restricting element204to increase flow area222and increase the downstream pressure.

In this manner PRV200may regulate a flow from PRV inlet224to PRV outlet226to substantially maintain a fluid pressure downstream of flow area222, based on a differential pressure across sensing element206. For example, PRV200may maintain the downstream fluid pressure within at least 1% to about 30% of a setpoint pressure, such as at within about 1%, 5%, 10%, 20%, or 30% of the setpoint pressure.

As discussed, the differential pressure across sensing element206may arise from the first pressure acting on first side240(exerted at least in part by the gas pressure in pressure chamber202) and the second pressure acting on second side242(exerted at least in part by one or more flow sections of the fluid flow between PRV inlet224and PRV outlet226). Consequently, PRV200may be configured such that the fluid pressure substantially maintained at PRV outlet226can be adjusted by adjusting the gas pressure in pressure chamber202.

Pressure chamber202is defined or surrounded at least in part by housing230of PRV200, which can be formed from any suitable material, such as, but not limited to metals, polymers, ceramics, or combinations thereof. Pressure chamber202may comprise a volume surrounded by a substantially gas-tight (e.g., gas-tight or gas-tight to the extent permitted by manufacturing tolerances) boundary, with the volume in fluid communication with sensing element206. The volume may have any suitable shape. In examples, the volume may be partially enclosed by a dome-shaped boundary, such as boundary265. Exterior276of housing230may be fluidly isolated from the gas-tight boundary of pressure chamber202

Pressure chamber202is configured to be isolated from flow pressures experienced by components of PRV200which fluidly communicate with a fluid flow from PRV inlet224to PRV outlet226, in order to substantially maintain the gas pressure of a gas present within pressure chamber202. For example, when pressure chamber202holds a gas at a gas pressure, pressure chamber202may be isolated from, for example, flow pressures at PRV inlet224and PRV outlet226, such that pressure chamber202may substantially maintain the gas pressure despite variations in the flow pressure. In examples, pressure chamber202may be isolated from valve inlet224, flow area222, valve seat220, restricting element204, second side242of sensing element206, and PRV outlet226. Sensing element206may be configured to such that first side240provides some portion of the pressure isolation between pressure chamber202and valve inlet224, flow area222, valve seat220, restricting element204, second side242of sensing element206, and PRV outlet226.

PRV200is configured to establish a pressure setpoint using a gas pressure in a pressure chamber such as pressure chamber202. PRV200includes a controller214configured to control (e.g., by increasing or decreasing) the gas pressure within pressure chamber202, in order to adjust the pressure setpoint within a system supplied by PRV200. Such adjustments may be beneficial in a variety of circumstances. For example, PRV200may be configured to receive a fluid from a main branch at PRV inlet224and provide the fluid at a lower pressure to a secondary branch via PRV outlet226. The primary branch may be, for example, a municipal water supply, while the secondary branch might comprise a portion of a water distribution system in a residence. It might be advantageous to vary the pressure setpoint of the residential distribution system based on, for example, a time of day. Controller214might act to increase the pressure setpoint during daylight hours as opposed to night time hours, if higher water demand is more likely to be initiated during the daylight hours due to occupant activity. Increasing the pressure setpoint during anticipated periods of higher demand might serve to lessen the impact of pressure transients throughout the system when multiple water loads are initiated substantially simultaneously. In an industrial type setting, controller214might act to establish certain pressure setpoints at certain times of day based on fluid loads anticipated from scheduled operations, historical data, or other indicators of anticipated demand.

Varying the pressure setpoint based on the actuation of specific fluid loads and the anticipated demand of the load may also provide one or more advantages in some examples. For example, controller214might receive an indication that a specific fluid load has been initiated and establish the pressure setpoint based on that specific fluid load. For example, in a residential water system, controller214might establish a first setpoint when a potentially higher demand load such as a washing machine is initiated, and establish a second setpoint when a potentially lower demand load such as a kitchen faucet is initiated. In an industrial setting, controller214might establish pressure setpoints based on the initiation of one or more specific processes. Matching a fluid pressure to a specific demand may generate a degree of fluid conservation by somewhat avoiding situations where fluid may be supplied to the specific load at a greater rate than the specific load requires.

Controller214is configured to establish a pressure setpoint by increasing or decreasing a gas pressure in pressure chamber202. In some examples, PRV200comprises a compressor208configured to increase a gas pressure inside pressure chamber202, e.g., by introducing gas into pressure chamber202, and a vent valve210configured to decrease a gas pressure inside pressure chamber, e.g., by defining a pathway through which gas may leave pressure chamber202.

In some examples, controller214communicates with compressor208and directs (e.g., controls directly or indirectly) compressor208to increase the gas pressure in pressure chamber202in order to adjust the pressure setpoint. Controller214may communicate with compressor208using, for example, compressor communication link246. Controller214may communicate with vent valve210and direct vent valve210to establish a valve position that decreases the gas pressure in pressure chamber202in order to adjust the pressure setpoint. Controller214may communicate with vent valve210using, for example, vent valve communication link248. Compressor communication link246and/or vent valve communication link248may be hard-line and/or wireless communications links. In some examples, vent valve communication link248and/or compressor communication link246may comprise some portion of controller214. In some examples, vent valve communication link248and/or compressor communication link246comprise a wired connection, a wireless Internet connection, a direct wireless connection such as wireless LAN, Bluetooth™, Wi-Fi™, and/or an infrared connection. Vent valve communication link248and/or compressor communication link246may utilize any wireless or remote communication protocol.

Controller214includes controller circuitry and can comprise any suitable arrangement of hardware, software, firmware, or any combination thereof, to perform the techniques attributed to controller214herein. For example, controller214may include any one or more microprocessors, digital signal processors (DSPs), application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), or any other equivalent integrated or discrete logic circuitry, as well as any combinations of such components.

Compressor208is configured to establish fluid communication with pressure chamber202. For example, in the example shown inFIG. 2, compressor208is configured to establish fluid communication with pressure chamber202through compressor conduit228of housing230and/or boundary265. Compressor208is configured to draw a gas through compressor inlet232, increase a pressure of the gas, and provide the gas via compressor conduit228to pressure chamber202. Compressor208may be a centrifugal compressor, a positive displacement compressor, or any other type of device which is configured to draw gas at an inlet and provide a higher pressure flow of the gas at an outlet. Compressor208may be configured to operate using an alternating current (AC) input power, direct current (DC) input power, or a combination. In examples, compressor208comprise a Brushless DC Motor (BLDC). In some examples, compressor208may include processing circuitry configured to control components of compressor208in response to a received electrical or electronic communication. The processing circuitry can be provided by controller214or may be separate from controller214. Compressor208may be configured to provide communications to other devices in data communication with compressor208. In examples, compressor208may be configured to establish a pressure barrier between pressure chamber202and compressor inlet232.

In the example shown inFIG. 2, PRV200includes a vent valve210configured to establish fluid communication with pressure chamber202. For example, atFIG. 2, vent valve210may establish fluid communication with pressure chamber202through vent conduit234of housing230. Vent valve210comprises vent valve outlet236and is configured to provide fluid communication between pressure chamber202and vent valve outlet236. Vent valve210may act to provide a fluid flow path to reduce the pressure Pc of pressure chamber202. In some examples, controller214is configured to communicate with vent valve210and control the operations of vent valve210. For example, controller214may communicate with vent valve210via vent valve communication link248.

In examples, vent valve210is configured to establish a pressure barrier between pressure chamber202and vent valve outlet236. Vent valve210may be a globe valve, a gate valve, a spool valve, a poppet valve, or any other type of valve mechanism which may be configured to control a flow path from an inlet to an outlet. In some examples, vent valve210may be a remotely actuated valve. In some examples, vent valve210comprises a solenoid actuator configured to influence the position of a plunger mechanically coupled to a flow restricting element, such as a valve disc. Vent valve210may configured to translate a flow restricting element based on a supply of a control fluid. For example, vent valve210may be a hydraulically or pneumatically operated valve. Vent valve210may include processing circuitry configured to control components of vent valve210in response to a received electrical or electronic communication. The processing circuitry can be provided by controller214or may be separate from controller214. Vent valve210may be configured to provide communications to other devices in data communication with compressor vent valve210. Controller214may direct vent valve210to fully or partially open and provide fluid communication between pressure chamber202and vent valve outlet236, and may direct vent valve210to fully or partially close and cease or reduce a fluid communication between pressure chamber202and vent valve outlet236.

To control the pressure within pressure chamber202, controller214may, at various times, conduct one or more of: direct compressor208to commence charging a gas into pressure chamber202, direct compressor208to cease charging the gas into pressure chamber202, direct vent valve210to fully or partially open and provide fluid communication between pressure chamber202and vent valve outlet236, and direct vent valve210to fully or partially close and cease or reduce a fluid communication between pressure chamber202and vent valve outlet236. As discussed below, the action selected by controller214for compressor208and vent valve210may depend on whether controller214is increasing or decreasing pressure within pressure chamber202.

PRV200further includes a pressure sensor212configured to generate a signal indicative of a pressure. For example, as depicted atFIG. 2, pressure sensor212may be configured to generate a signal indicative of a pressure at PRV outlet226, and/or indicative of a pressure downstream of flow area222. Pressure sensor212may generate a signal as a function of a pressure imposed on some portion of pressure sensor212. Pressure sensor212may be configured to use any type of force collector to sense the outlet pressure, including, for example, diaphragms, pistons, bourdon tubes, bellows, or some other collector. Pressure sensor212may transduce the pressure into an electrical signal using, for example, piezoresistive strain gauges, capacitors, electromagnets, optical fibers, potentiometric wipers, or other devices. Pressure sensor212may be configured to sense an absolute pressure or a gauge pressure. The signal indicative of the pressure generated by pressure sensor212may be an analog electrical signal or a digital signal. Pressure sensor212may include processing circuitry configured to interpret a response of the force collector and generate the signal indicative of the pressure, and/or controller214may include processing circuitry configured to interpret a response of the force collector and generate the signal indicative of the pressure. Pressure sensor212may be configured to provide communicate the signal indicative of the pressure to other devices in data communication with pressure sensor212.

Controller214is configured to receive the signal indicative of the pressure from pressure sensor212. Controller214may receive the signal indicative of the pressure via, for example, sensor communication link238between controller214and pressure sensor212. Controller214is configured to compare the signal indicative of the pressure received from pressure sensor212with a pressure setpoint. The pressure setpoint may be stored in a memory of controller214or of another device of system200or communicatively coupled to controller214. The memory may include any volatile or non-volatile media, such as a random access memory (RAM), read only memory (ROM), non-volatile RAM (NVRAM), electrically erasable programmable ROM (EEPROM), flash memory, and the like. In some examples, the memory may be internal to controller214. In addition, in some examples, the memory or another memory may also store executable instructions for causing the one or more controllers described herein to perform the actions attributed to them.

Sensor communication link238may be hard-line and/or wireless communications link. Sensor communication link238may comprise some portion of controller214. Sensor communication link238may comprise a wireless Internet connection, a direct wireless connection such as wireless LAN, Bluetooth™, Wi-Fi™, and/or an infrared connection. Sensor communication link238may utilize any wireless or remote communication protocol.

Based on the comparison of the indicative signal from pressure sensor212and the pressure setpoint, controller214is configured to increase or decrease a pressure in pressure chamber202. Controller214may direct compressor208to operate such that compressor208draws a gas such as air into compressor inlet232and directs the gas into pressure chamber202, increasing the gas pressure of pressure chamber202. Controller214may control vent valve210and cause vent valve210to operate (e.g., to open) to provide fluid communication between pressure chamber202and an environment external to pressure chamber202, allowing pressure chamber202to vent and decrease the gas pressure of pressure chamber202.

Utilizing compressor208and vent valve210, controller214may be configured to increase or decrease the pressure of a secondary fluid branch in fluid communication with PRV outlet226of PRV200. For example, to increase or decrease a pressure in the secondary branch, controller214may receive or establish a revised pressure setpoint reflective of the new desired pressure. Based on a comparison of the revised setpoint and a signal indicative of the pressure provided by pressure sensor212, controller214may control compressor208and/or vent valve210to increase or decrease the pressure in pressure chamber202, causing PRV200to establish a configuration causing an increase or decrease of the pressure at PRV outlet226, until a comparison of the revised setpoint and the signal indicative of the pressure provided by pressure sensor212indicates the pressure in pressure chamber202is satisfactory (e.g., within a predetermined range of the pressure setpoint, such as within 5% to 30%, such as within 5%, 10%, 20%, or 30% of the pressure setpoint in various examples).

In some examples, controller214may be provided with one or more pressure setpoints, e.g., a revised setpoint, via a communication from another device or via a user interface of controller214. The user interface can have any suitable configuration. For example, the user interface can include a button or keypad, a speaker configured to receive voice commands from a user, a display, such as a liquid crystal (LCD), light-emitting diode (LED), or organic light-emitting diode (OLED). In some examples the display may be a touch screen. The user interface is configured to receive user input, e.g., in the form of pressing one or more buttons on a keypad or via a touch screen, which may be user input selecting a desired pressure setpoint, for example. In some examples, the user interface is also configured to display information, such as one or more pressure setpoints (e.g., the current setpoint being used by controller214to control PRV200or one or more predetermined pressure setpoints from which the user can select to input a desired pressure setpoint).

In some examples, controller214may be configured to establish a desired setpoint based on a particular criteria. For example, controller214may be configured to establish a revised setpoint based on a time of day, a scheduled operation requiring or anticipated to require a particular fluid demand from PRV200, and/or the actuation of a specific fluid load supplied by PRV200.

In some examples, PRV200may be a reverse-seated valve. PRV200may be configured such that a movement of sensing element206in a direction toward valve seat220(e.g., in the direction D1) causes restricting element204to translate and increase flow area222. The movement of sensing element206toward valve seat220may be caused by a decrease in the pressure of a fluid section within PRV200. The fluid section may be a fluid section downstream of flow area222. The movement of sensing element206toward valve seat220may be caused by an increase in the pressure of a gas within pressure chamber202. Controller214may increase the pressure of the gas within pressure chamber202causing sensing element to move in a direction toward valve seat220(e.g., in the direction D1) and increase flow area222. The increase in flow area222may reduce the pressure drop of a fluid flowing through flow area222, increasing the pressure at PRV outlet226.

PRV200may be configured such that a movement of sensing element206in a direction away from valve seat220(e.g., in the direction D2) causes restricting element204to translate and decrease flow area222. The movement of sensing element206away from valve seat220may be caused by an increase in the pressure of a fluid section within PRV200. The fluid section may be a fluid section downstream of flow area222. The movement of sensing element206away from valve seat220may be caused by a decrease in the pressure of a gas within pressure chamber202. Controller214may decrease the pressure of the gas within pressure chamber204causing sensing element to move in a direction away from valve seat220(e.g., in the direction D2) and decrease flow area222. The decrease in flow area222may increase the pressure drop of a fluid flowing through flow area222, decreasing the pressure at PRV outlet226.

Restricting element204includes any suitable structure and is configured to translate in directions D1 and D2 using any suitable structure. In some examples, PRV200includes a spring element296configured to translate restricting element204to close PRV200. Spring element296may be configured to transmit a force to restricting element204in a direction which biases restricting element204to reduce (or eliminate in some examples) flow area222. The biasing force transmitted by spring element296to restricting element204may be in opposition to a force transmitted to restricting element204. Spring element296may be configured such that, if a force transmitted by sensing element206fails below a threshold, the biasing force transmitted by spring element296causes restricting element204to translate in a manner reducing or eliminating flow area222of PRV200. Spring element296may be configured to be in either tension or compression as it transmits the biasing force to restricting element204. For example, spring element296may be in compression and configured to transmit the biasing force to restricting204element by extending. As another example, spring element296may be in tension and configured to transmit the biasing force to restricting element204by contracting.

For example,FIG. 2illustrates spring element296in compression between a section of PRV200and restricting element204. Spring element296is configured to transmit a force to restricting element204substantially in the direction D2, biasing restricting element204to translate in a manner reducing or eliminating flow area222. The biasing force transmitted by spring element296to restricting element204is in opposition to a force transmitted by sensing element206in the direction D1, which causes restricting element204to translate in a manner increasing flow area222. Spring element296is configured such that, if the force transmitted by sensing element206in the direction D1 fails below a threshold, the biasing force transmitted by spring element296causes restricting element204to translate in a manner reducing or eliminating flow area222of PRV200. For example, if controller214utilizes vent valve210to decrease the pressure in pressure chamber202as previously described, and the decreased pressure reduces the force transmitted by sensing element206in the direction D1 to below the threshold, the biasing force transmitted by spring element296may cause restricting element204to translate in a manner reducing or eliminating flow area222of PRV200.

In this manner, spring element296may act as a shut off mechanism for PRV200, acting to reduce or eliminate flow area222when controller214recognizes a condition under which PRV200should close and, in response, opens vent valve210to reduce the pressure in pressure chamber202. For example, in some examples, controller214may receive a leak signal from a leak detection system monitoring a fluid branch downstream of PRV200. Controller214may be configured such that, in response to receiving the leak signal, controller214causes vent valve210to open and reduce the pressure in pressure chamber202to a level where spring element296causes restricting element204to translate and close PRV200, thereby eliminating (to the extent possibly by the fluid seals of PRV200) fluid flow through PRV.

In examples, controller214may cause vent valve210to open and equalize the pressure in pressure chamber202with an atmosphere surrounding PRV200in response to receiving a leak signal from a leak detection system. For example, PRV200may be PRV114(FIG. 1). A leak detection system182(FIG. 1) might be configured to detect leakage from branch circuit118and controller214of PRV114may be configured to receive a leak signal from leak detection system182. In response to the leak signal, controller214may reduce a pressure in pressure chamber202, so that spring element296closes PRV114.

In some examples, a PRV may be configured to function as a back-pressure regulator, to substantially maintain a pressure of fluid flow upstream of the flow area of the pressure regulating valve. For example,FIG. 3illustrates an example PRV300configured to function as a back-pressure regulator. PRV300comprises PRV inlet324and PRV outlet326and is configured to provide a flow path for a fluid between PRV inlet324and PRV outlet326. PRV300may be configured to receive a fluid at PRV inlet324and regulate a fluid flow through flow area322and PRV outlet326, in order to substantially maintain a pressure of a flow section upstream of flow area322. For example, PRV300may be configured receive a fluid from main circuit102and regulate a fluid flow to fluid conduit164to substantially maintain a fluid pressure in main circuit102(FIG. 1). PRV300may be an example of PRV150described with reference toFIG. 1. PRV inlet324, flow area322, and PRV outlet326may be configured individually and relation to each other in the same manner as that discussed for the like-named components of PRV200.

As illustrated, PRV300further comprises restricting element304, valve disc316, valve stem318, valve seat320, sensing element306defining first side340, second side342, and perimeter344, pressure chamber302, housing330having a housing exterior376and a boundary365, controller314, pressure sensor312, compressor308, compressor conduit328, compressor inlet332, vent valve310, vent valve outlet336, vent conduit334, sensor communication link338, compressor communication link346, vent valve communication link348, and spring element396, which may be configured individually and relation to each other in the same manner as that discussed for the like-named components of PRV200.

For example, sensing element306is configured to influence the translation of restricting element304. For example, sensing element306may be mechanically coupled to restricting element304. Sensing element306includes first side340and a second side342, and may be configured such that sensing element306experiences motion based on a differential pressure between first side340and second side342. The differential pressure may arise from a first pressure acting on first side340and a second pressure acting on second side342. For example, sensing element306may comprise a diaphragm or a piston having a first side and a second side.

The first pressure acting on first side340of sensing element306may arise from a gas pressure within a pressure chamber302. The second pressure acting on second side342of sensing element306may arise from fluid communication with one or more fluid sections of a fluid between and including PRV inlet324and flow area322. Thus, the differential pressure experienced across sensing element306may be dependent on both a gas pressure within pressure chamber302and a fluid pressure between and including PRV inlet324and PRV outlet326.

PRV300may be configured to adjust flow area322in response to changes in an upstream pressure, such as a pressure at PRV inlet324, or some other fluid section upstream of flow area322. For example, with a substantially constant gas pressure (e.g., constant or nearly constant, such as less than or equal to a 5% change) in pressure chamber302, an increase in the upstream pressure may increase the second pressure acting on second side342, and cause sensing element306to reposition restricting element304in a manner that increases flow area322(e.g., sensing element306may reposition restricting element304in an opening direction such as D2 to increase flow area222). The increased flow area322may cause a decrease in the upstream pressure at, for example, PRV inlet324, or some other fluid section upstream of flow area322.

Alternatively, with a substantially constant gas pressure in pressure chamber302, a decrease in upstream pressure may decrease the second pressure acting on second side342, and cause sensing element306to reposition restricting element304in a manner that decreases flow area322(e.g., sensing element306may reposition restricting element304in a closing direction such as D1 to decrease flow area322). The decreased flow area322may cause an increase in the upstream pressure at, for example, PRV inlet324, or some other flow section upstream of flow area322. In some examples, a decrease in upstream pressure may result in sensing element306acting to fully shut PRV300.

PRV300may be configured such that sensing element306operates around a specific pressure setpoint, based on the gas pressure in pressure chamber302. Increases in upstream pressure above the setpoint may cause sensing element306to translate restricting element304to increase flow area322(e.g., cause sensing element306to move in the direction D2) and decrease the upstream pressure. Decreases in upstream pressure below the setpoint may cause sensing element306to translate restricting element304to decrease flow area322(e.g., cause sensing element306to move in the direction D1) and increase the downstream pressure. In this manner PRV300may regulate a flow from PRV inlet324to PRV outlet326to substantially maintain a fluid pressure upstream of flow area322, based on a differential pressure across sensing element306. For example, PRV300may maintain the upstream pressure within 1% to 30% of a setpoint pressure, such as within 1%, 5%, 10%, 20%, or 30% of the setpoint pressure.

Controller314is configured to establish a pressure setpoint by increasing or decreasing a gas pressure in pressure chamber302. To control the pressure within pressure chamber302, controller314may, at various times, conduct one or more of: direct compressor308to commence charging a gas into pressure chamber302, direct compressor308to cease charging the gas into pressure chamber302, direct vent valve310to fully or partially open and provide fluid communication between pressure chamber302and vent valve outlet336, and direct vent valve310to fully or partially close and cease or reduce a fluid communication between pressure chamber302and vent valve outlet336. As discussed below, the action selected by controller314for compressor308and vent valve310may depend on whether controller314is increasing or decreasing pressure within pressure chamber302.

Controller314may communicate with compressor308via compressor communication link346and direct compressor308to increase the gas pressure in pressure chamber302. Controller314may communicate with vent valve310via vent valve communication link348and direct vent valve310to establish a valve position that decreases the gas pressure in pressure chamber302.

PRV300further includes a pressure sensor312configured to generate a signal indicative of a pressure. For example, as depicted atFIG. 3, pressure sensor312may be configured to generate a signal indicative of a pressure at PRV inlet324and/or indicative of a pressure upstream of flow area322. Controller314is configured to receive the signal indicative of the pressure from pressure sensor312. Controller314may receive the signal indicative of the pressure via, for example, sensor communication link338between controller314and pressure sensor312. Controller314may be configured to compare the signal indicative of the pressure received from pressure sensor312with a pressure setpoint. The pressure setpoint may be stored in a memory of controller314or a memory of another device. Based on the comparison of the indicative signal from pressure sensor312and the pressure setpoint, controller314may be configured to increase or decrease a pressure in pressure chamber302using compressor308(to increase the pressure) or vent valve310(to decrease the pressure), e.g., as discussed with respect to controller214, compressor208, and vent valve210ofFIG. 2.

Utilizing compressor308and vent valve310, controller314may be configured to increase or decrease the pressure of an upstream fluid branch in fluid communication with PRV inlet324of PRV300. For example, to increase or decrease a pressure in the upstream fluid branch, controller314may receive or establish a revised pressure setpoint reflective of the new desired pressure. Based on a comparison of the revised setpoint and a signal indicative of the pressure provided by pressure sensor312, controller314may control compressor308and/or vent valve310to increase or decrease the pressure in pressure chamber302, causing PRV300to establish a configuration causing an increase or decrease of the pressure at PRV inlet324, until a comparison of the revised setpoint and the signal indicative of the pressure provided by pressure sensor312indicates the pressure in pressure chamber302is satisfactory (e.g., within a predetermined range of the pressure setpoint, such as within 5% to 30%, such as within 5%, 10%, 20%, or 30% of the pressure setpoint in various examples).

In some examples, PRV300may be a normally-seated valve. PRV300may be configured such that a movement of sensing element306in a direction away from valve seat320(e.g., in the direction D2) causes restricting element304to translate and increase flow area322. The movement of sensing element306away from valve seat320may be caused by a decrease in the pressure of a fluid section within PRV300. The fluid section may be a fluid section upstream of flow area322. The movement of sensing element306away from valve seat320may be caused by a decrease in the pressure of a gas within pressure chamber302. Controller314may decrease the pressure of the gas within pressure chamber304causing sensing element306to move in a direction away from valve seat320(e.g., in the direction D2) and increase flow area322. The increase in flow area322may reduce the pressure drop of a fluid flowing through flow area322(or initiate a fluid flow through flow area322), decreasing the pressure at PRV inlet324.

PRV300may be configured such that a movement of sensing element306in a direction toward valve seat320(e.g., in the direction D1) causes restricting element304to translate and decrease flow area322. The movement of sensing element304toward valve seat320may be caused by a decrease in the pressure of a fluid section within PRV300. The fluid section may be a fluid section upstream of flow area322. The movement of sensing element304toward from valve seat320may be caused by an increase in the pressure of a gas within pressure chamber302. Controller314may increase the pressure of the gas within pressure chamber302causing sensing element306to move in a direction toward valve seat320(e.g., in the direction D1) and decrease flow area322. The decrease in flow area322may increase the pressure drop of a fluid flowing through flow area322(or cease a fluid flow through flow area322), increasing the pressure at PRV inlet324.

Restricting element304includes any suitable structure and is configured to translate in directions D1 and D2 using any suitable structure. In some examples, PRV300may include spring element396. Spring element396may be configured to transmit a force to restricting element304substantially in the direction D1, biasing restricting element304to translate in a manner reducing or eliminating flow area322. Spring element396may act as a shut off mechanism for PRV300, acting to reduce or eliminate flow area322when controller314recognizes a condition under which PRV300should close and, in response, opens vent valve310to reduce the pressure in pressure chamber302. For example, in some examples, controller314is configured to receive a leak signal from a leak detection system monitoring a fluid branch upstream of PRV300, and, in response to receiving the leak signal, controller314opens vent valve310and reduces the pressure in pressure chamber302to a level where spring element396causes restricting element304to translate and close PRV300.

In some examples, controller214(FIG. 2) and/or controller314(FIG. 3) may comprise a Proportional-Integral-Derivative (PID) controller. The PID controller may receive a pressure signal from a pressure sensor such as pressure sensor212and/or pressure sensor312as a process variable, and may periodically determine an error based on a difference between a pressure setpoint and a pressure indicated by the pressure signal. The PID controller may produce a control signal based on the error. Controller214may control compressor208and/or vent valve210based on the control signal. Controller314may control compressor308and/or vent valve310based on the control signal.

The PID controller may produce the control signal using a proportional term (P) proportional to the value of the error. The PID may produce the control signal using an integral term (I) based on past values of the error integrated over time. The PID may produce the control signal using a derivative term (D) based on a rate of change of the error. The PID controller may determine the control signal based on a weighted sum of the P, I, and/or D terms. The PID controller may be a digital PID controller which converts an analog pressure signal from a sensor to a digital signal using an analog-to-digital (A/D) convertor. The PID controller may comprises one or more analog components such as one or more operational amplifiers.

The controller comprising the pressure regulating valve may be configured to receive a communication signal from, for example, one or more fluid loads, and determine a pressure setpoint based on the communication signal.FIG. 4is a conceptual diagram of an example PRV400comprising at least a vent valve408, a compressor410, a controller414, and a pressure sensor416. Components of PRV400may be configured individually and relation to each other in the same manner as that discussed for the like-named components of PRV200.

A fluid circuit498is configured to provide fluid to fluid load488and fluid load490. Fluid load488and fluid load490may be parallel fluid loads. Each of fluid load488and fluid load490are configured to communicate with controller414when the respective loads are actuated. Fluid load488may communicate with controller414via communication link482. Fluid load490may communicate with controller414via communication link484. Communication links482,484may be hard-line and/or wireless communications links, e.g., any of the example communication links described above.

PRV400is configured to receive a fluid from fluid circuit402and provide fluid to fluid circuit498at a pressure based on a pressure setpoint. The pressure setpoint may be based on the actuation of fluid load488and/or fluid load490. For example, controller414may be configured to receive a first signal from fluid load488via communication link482and establish a first pressure setpoint in response to the first signal. Controller414may direct compressor410to increase pressure in a pressure chamber (not shown) of PRV400and/or direct vent valve408to decrease pressure in the pressure chamber of PRV400, until pressure sensor416indicates the first setpoint has been established in fluid circuit498(e.g., the pressure in fluid circuit498is within a predetermined range of the first setpoint, such as equal to or within 1% to 30% of the first setpoint).

Controller414may be configured to receive a second signal from fluid load490via communication link484and establish a second pressure setpoint in response to the second signal. The second setpoint may be different (e.g. higher or lower) than the first setpoint. Controller414may direct compressor410to increase pressure in a pressure chamber (not shown) of PRV400and/or direct vent valve408to decrease pressure in the pressure chamber of PRV400, until pressure sensor416indicates the second setpoint has been established in fluid circuit498(e.g., the pressure in fluid circuit498is within a predetermined range of the second setpoint, such as equal to or within 1% to 30% of the second setpoint).

In some examples, controller414may also be configured to establish a third pressure setpoint based on receipt of both the first signal from fluid load488and the second signal from fluid load490. Controller414may be configured to receive signals and establish a pressure setpoint for any number of fluid loads, and establish a pressure setpoint for any combination of fluid loads.

For example, fluid circuit402might be a municipal water main and fluid circuit498might be a residential water main. PRV400may be configured to receive a higher pressure fluid from fluid circuit402and provide a lower pressure fluid to fluid circuit498. Fluid load488and fluid load490may be residential fluid loads. For example, fluid load488might be kitchen faucet while fluid load490might be a dishwasher. It may be advantageous for PRV400to substantially maintain fluid circuit498at different pressures depending on which or fluid loads488,490are in operation. Controller414may be configured to substantially maintain a first pressure in fluid circuit498when fluid load490(e.g., dishwasher) is actuated (e.g., operating and using water), based on the anticipated water demand of fluid load490. Controller414may be configured to substantially maintain a second pressure less than the first pressure when fluid load488(e.g., kitchen faucet) is actuated, in order to reduce over-supply of water for the generally lower water demand of tasks typically performed with fluid load488. It may be advantageous to configure controller414to substantially maintain a third pressure greater than the first pressure and the second pressure when both fluid load488and fluid load490are actuated, in order to provide a sufficient flow of fluid through the residential piping when both loads are operating simultaneously.

PRV400may also be configured to operate as a back-pressure regulator substantially maintaining a pressure in fluid circuit498and providing a fluid flow from fluid circuit498to fluid circuit402to substantially maintain the pressure. Fluid load488and fluid load490may require differing pressure setpoints for fluid circuit498. For example, fluid load488may be a first bank of flow spray nozzles operating effectively at a first pressure while fluid load490may be a second bank of spray nozzles operating effectively at a second pressure different from the first pressure. Controller414may be configured to receive a signal from each of fluid load488and fluid load490, and establish a pressure setpoint for fluid circuit498depending on whether the first pressure or second pressure is desired.

The compressor, vent valve, sensor, and controller of PRV400may be configured individually and relation to each other in the same manner as that discussed for the like-named components of PRV200and/or PRV300. PRV400may also comprise a PRV inlet, a flow area, a PRV outlet, a restricting element, a valve disc, a valve stem, a valve seat, a sensing element, a first side, a second side, a perimeter, a pressure chamber, a housing, a housing exterior, a boundary, a compressor conduit, a compressor inlet, a vent valve outlet, a vent conduit, a sensor communication link, a compressor communication link, a vent valve communication link, and a spring element, which may be configured individually and relation to each other in the same manner as that discussed for the like-named components of PRV200and/or PRV300.

A compressor of a PRV may comprise a compressor housing mechanically coupled to or integral with the housing exterior of the PRV.FIG. 5illustrates a portion of an example PRV500comprising an example compressor508. Compressor508includes a compressing element592in fluid communication with compressor inlet532and compressor outlet573. Compressing element592is configured to establish a suction at compressor inlet532and provide a discharge at compressor outlet573. Compressing element592may comprise, for example, an impellor or a piston.

Compressor508includes compressor housing571at least partially surrounding compressing element592. Compressor housing571may be mechanically coupled to or integral with housing exterior576of PRV500. Compressor outlet573may be in fluid communication with compressor conduit528, which is in fluid communication with pressure chamber502. For example, compressor conduit528may extend through housing530, housing exterior576, and/or boundary565of pressure chamber502.

In some examples, a vent valve of a PRV may be mechanically coupled to or integral with the exterior housing of the PRV.FIG. 5illustrates an example vent valve510mechanically coupled to or integral with housing exterior576. Vent valve inlet574of vent valve510is in fluid communication with vent conduit534, which is in fluid communication with pressure chamber502. For example, vent conduit534may extend through housing530, housing exterior576, and/or boundary565. Vent valve510may comprise one or more valve components configured to fluidly isolate vent valve inlet574and vent valve outlet536.

In some examples, a controller of a PRV may be positioned outside the housing of the PRV or may be mechanically coupled to or integral with the housing exterior of the pressure regulating valve.FIG. 5illustrates an example controller514at least partially surrounded by controller housing572, with controller housing572mechanically coupled to or integral with housing exterior576. In some examples, a single housing (not shown) may cover one or more of controller514, compressor508, and vent valve510, in any combination. The single housing may be mechanically coupled to or integral with housing exterior576. Controller housing572is configured to protect circuitry of controller514from environmental contaminants.

Pressure chamber502, housing530, housing exterior576, boundary565, controller514, compressor508, compressor conduit528, compressor inlet532, vent valve510, vent valve inlet574, vent valve outlet536, and vent conduit534may be configured individually and relation to each other in the same manner as that discussed for the like-named components of PRV200, PRV300, and/or PRV400. In some examples, PRV500may also comprise a PRV inlet, a flow area, a PRV outlet, a restricting element, a valve disc, a valve stem, a valve seat, a sensing element, a first side, a second side, a perimeter, a pressure sensor, a sensor communication link, a compressor communication link, a vent valve communication link, and a spring element, which may be configured individually and relation to each other in the same manner as that discussed for the like-named components of PRV200, PRV300, and/or PRV400.

In some examples, a compressor of a PRV may be internal to a pressure chamber of the PRV, the pressure chamber being the same pressure chamber that the controller can introduce gases into.FIG. 6illustrates a portion of an example PRV600comprising compressor608, which is an example compressor that is substantially within pressure chamber602and is likewise surrounded by housing630. Compressor608can be configured like the example compressors described with reference toFIGS. 2-5, but is positioned substantially within pressure chamber602. For example, compressor608may be surrounded by the volume within the gas-tight boundary of pressure chamber602. Compressor inlet632of compressor608is fluidically connected to compressor outlet673via compressor conduit628, which extends through housing630, housing exterior676, and/or boundary665. Compressor outlet673is in fluid communication with pressure chamber602. Compressor608may comprise compressing element692in fluid communication with compressor inlet632and compressor outlet673. Compressing element692may be surrounded by pressure chamber602such that compressor inlet632is in fluid communication with compressor conduit628extending through housing630, housing exterior676, and/or boundary665, and compressor outlet673is in fluid communication with the volume within the gas-tight boundary of pressure chamber602.

In some examples, a vent valve of a PRV can be internal to a pressure chamber of the PRV, the pressure chamber being the same pressure chamber from which the vent valve releases gases.FIG. 6illustrates an example of a vent valve610that substantially within pressure chamber602and surrounded by housing630. Vent valve636can be configured like the example vent valves described with reference toFIGS. 2-5, but is positioned substantially within pressure chamber602. Vent valve outlet636of vent valve610is in fluid communication with vent inlet674via vent conduit634, which may extend through housing630, housing exterior676, and/or boundary665. Vent valve inlet674may be in fluid communication with pressure chamber602. Vent valve610may comprise one or more valve components configured to fluidly isolate vent valve inlet674and vent valve outlet636. Vent valve610may be surrounded by pressure chamber602such that vent valve outlet636is in fluid communication with vent conduit634extending through housing630and/or boundary665, and vent valve inlet674is in fluid communication with the volume within the gas-tight boundary of pressure chamber602.

In some examples, a controller of a PRV can be internal to a pressure chamber of the PRV, the pressure chamber being a chamber for which the controller controls the pressure.FIG. 6illustrates an example controller614that is substantially within pressure chamber602and surrounded by housing630. Controller614can be configured like the example controllers described with reference toFIGS. 2-5, but is positioned substantially within pressure chamber602. In some examples, a hard-line connection680may extend through housing630, exterior housing676, and/or boundary665. Hard-line connection680may be in electrical communication with controller614. Hard-line connection680may be configured to provide data communications and/or electrical power to controller614.

A hatch675may be configured to allow access into pressure chamber602through housing630, housing exterior676, and/or boundary665. Hatch675may be configured to have an open position providing access to the volume within pressure chamber602and have a closed position, where hatch675forms a portion of the gas-tight boundary around pressure chamber602when in the closed position.

Pressure chamber602, housing630, housing exterior676, boundary665, controller614, compressor608, compressor element692, compressor conduit628, compressor inlet632, compressor outlet673, vent valve610, vent valve outlet636, vent valve inlet674, and vent conduit634may be configured individually and relation to each other in the same manner as that discussed for the like-named components of PRV200, PRV300, PRV400, and/or PRV500. In some examples, PRV600may also comprise a PRV inlet, a flow area, a PRV outlet, a restricting element, a valve disc, a valve stem, a valve seat, a sensing element, a first side, a second side, a perimeter, a sensor, a sensor communication link, a compressor communication link, a vent valve communication link, and a spring element, which may be configured individually and relation to each other in the same manner as that discussed for the like-named components of PRV200, PRV300, PRV400and/or PRV500.

In examples, a vent valve and a compressor of a PRV may both be in fluid communication with a chamber conduit extending through the housing, housing exterior, and/or boundary of the pressure chamber. For example,FIG. 7illustrates a portion of an example PRV700comprising vent valve710, compressor708, and controller714. Vent valve710, compressor708, and controller714are surrounded by a control housing794. Control housing794may be mechanically coupled to or integral with housing exterior776.

Vent valve710comprises vent valve outlet736and vent valve inlet774. Vent valve710may comprise one or more valve components configured to fluidly isolate vent valve inlet774and vent valve outlet736. Vent valve inlet774may be configured to be in fluid communication with chamber conduit793. Chamber conduit793may extend through housing730, housing exterior776, and/or boundary765. Compressor708may comprise compressing element792in fluid communication with compressor inlet732and compressor outlet773. Compressor outlet573may be configured to be in fluid communication with chamber conduit593.

Pressure chamber702, housing730, housing exterior776, boundary765, controller714, compressor708, compressor inlet732, compressor element792, compressor outlet773, vent valve710, vent valve outlet736, and vent valve inlet774may be configured individually and relation to each other in the same manner as that discussed for the like-named components of PRV200, PRV300, PRV400, PRV500, and/or PRV600. In some examples, PRV700may also comprise a PRV inlet, a flow area, a PRV outlet, a restricting element, a valve disc, a valve stem, a valve seat, a sensing element, a first side, a second side, a perimeter, a pressure sensor, a sensor communication link, a compressor communication link, a vent valve communication link, a spring element, a hatch, and a hard-line connection, which may be configured individually and relation to each other in the same manner as that discussed for the like-named components of PRV200, PRV300, PRV400, PRV500, and/or PRV600.

FIG. 8illustrates a flow diagram of an example technique for regulating a pressure. Although the technique is described with reference to PRV200ofFIG. 2, in other examples, the technique may be used with another PRV. In addition, controller214of PRV alone or in combination with controllers of other devices can perform any part of the technique shown inFIG. 8.

Controller214receives a pressure signal indicative of a pressure (802). In some examples, the pressure signal may be indicative of a pressure at valve outlet226of PRV200. In some examples, pressure sensor212generates the pressure signal indicative of the pressure and transmits the signal to controller214using any suitable communication link. Controller214determines a pressure offset between the pressure indicated by the pressure signal and a pressure setpoint (804). For example, controller214can determine the pressure based on a signal characteristic of the pressure signal, such as an amplitude or frequency of the pressure signal. As an example, controller214can compare the signal characteristic of the pressure signal to predetermined pressure values and determine the pressure associated with the signal characteristic, e.g., in a memory of controller214or another device. The pressure setpoint referenced by controller214can also be stored in a memory of controller214or another device.

Controller214alters a pressure in pressure chamber202of PRV200based on the determined pressure offset (806). For example, controller214may alter the pressure by directing compressor208to charge pressure chamber202and increase the pressure in pressure chamber202. In addition, or instead, controller214may alter the pressure by directing vent valve210to vent pressure chamber202and decrease the pressure in the pressure chamber. For example, in response to determining the pressure offset indicates the pressure indicated by pressure sensor212is greater than the pressure setpoint, controller214may alter the pressure by directing vent valve210to vent pressure chamber202and decrease the pressure in the pressure chamber, causing sensing element206to reposition restricting element204in a manner that increases a pressure drop of a fluid as it flows through flow area222. In response to determining the pressure offset indicates the pressure indicated by pressure sensor212is less than the pressure setpoint, controller214may alter the pressure by directing compressor208to charge pressure chamber202and increase the pressure in the pressure chamber, causing sensing element206to reposition restricting element204in a manner that decreases a pressure drop of a fluid as it flows through flow area222.

As a result of the pressure in pressure chamber202being altered (806), controller214causes sensing element206in fluid communication with pressure chamber202to move (808), where movement of sensing element206alters flow area222between valve inlet224and valve outlet226. As discussed above, the size (e.g., volume) of flow area22affects the fluid pressure in the fluid circuit including PRV200. For example, increasing flow area222can decrease pressure through PRV200and decreasing flow area222can increase pressure through PRV200.

In one or more examples, functions described herein may be implemented in hardware, software, firmware, or any combination thereof. For example, the various components and functions ofFIGS. 1-8may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions may be stored on a tangible computer-readable storage medium and executed by a processor or hardware-based processing unit.