阅读说明：本技术 用于压力调节器的可膨胀引导组件 (Expandable guide assembly for pressure regulator ) 是由 J·K·米尔斯 O·W·范多兰 于 2020-04-29 设计创作，主要内容包括：本发明公开了一种引导组件,该引导组件被配置用于与各种类型的流量控制器一起使用。这些配置包含具有内部流动网络的歧管,该内部流动网络连接先导阀和可调节孔口。先导阀可具有固定且可变的压差。在一个具体实施中,歧管包括一对可分离的块,每个块包含内部流动网络的一部分。该构造还允许歧管与例如用于另外的先导阀的另外的块一起膨胀。该特征配置在工作监视器系统或部署多级压力调节的那些系统中使用的歧管。(A pilot assembly is configured for use with various types of flow controllers. These configurations include a manifold having an internal flow network connecting a pilot valve and an adjustable orifice. The pilot valve may have a fixed and variable pressure differential. In one implementation, the manifold includes a pair of separable blocks, each block containing a portion of the internal flow network. This configuration also allows the manifold to expand with additional blocks, for example for additional pilot valves. This feature configures the manifold for use in a work monitor system or those systems that deploy multi-stage pressure regulation.)

1. A pilot valve assembly comprising:

a manifold having an internal flow network; and

a flow controller connected to the internal flow network to allow fluid to flow between the flow controller and the internal flow network, the flow controller comprising:

fixing a pilot valve;

a first adjustable pilot valve; and

the flow restrictor may be adjustable.

2. The pilot valve assembly according to claim 1, wherein said internal flow network connects an outlet of said first adjustable pilot valve with said adjustable flow restrictor.

3. The pilot valve assembly of claim 1, wherein the internal flow network connects the outlet of the first adjustable pilot valve with a port on the manifold that receives a fitting.

4. The pilot valve assembly of claim 1, wherein the internal flow network connects the outlet of the fixed pilot valve to the inlet of the first adjustable pilot valve.

5. The pilot valve assembly of claim 1, wherein said manifold comprises blocks separable from one another, each block having a portion of said internal flow network.

6. The pilot valve assembly according to claim 1, wherein said manifold comprises blocks separable from each other, and wherein said fixed pilot valve and said adjustable flow restrictor are provided in different blocks.

7. The pilot valve assembly of claim 1, wherein the manifold comprises blocks that are separable from one another, and wherein the first adjustable pilot valve and the adjustable flow restrictor are disposed in different blocks.

8. The pilot valve assembly of claim 1, wherein the flow controller further comprises:

a second adjustable pilot valve.

9. The pilot valve assembly of claim 8, wherein the manifold comprises blocks that are separable from one another, and wherein the first and second adjustable pilot valves are disposed in different blocks.

10. The pilot valve assembly of claim 1, wherein the flow controller further comprises:

a check valve.

11. The pilot valve assembly of claim 1, wherein the manifold comprises blocks that are separable from one another, and wherein the first adjustable pilot valve and the check valve are disposed in different blocks.

12. A pilot valve assembly comprising:

a manifold comprising a first block and a second block that form a flow network when attached to each other;

a fixed pilot valve and a first variable pilot valve disposed on the first block; and

an adjustable flow restrictor disposed on the second block,

wherein the first block is separable from the second block.

13. A pilot valve assembly according to claim 12, further comprising:

a check valve disposed on the second block.

14. A pilot valve assembly according to claim 12, further comprising:

a third block disposed between the first block and the second block, the third blocks forming part of the flow network when attached to each other,

wherein the third block is separable from the first block and the second block.

15. A pilot valve assembly according to claim 14, further comprising:

a second variable pilot valve disposed on the third block.

16. A pilot valve assembly comprising:

a first manifold block housing a fixed pilot valve and a variable pilot valve; and

a second manifold block detachably attached to the first manifold block, the second manifold block having a port for receiving a fitting and an internal flow network placing an outlet on the variable pilot valve in flow connection with the port,

wherein the internal flow network includes parallel paths that terminate at the ports and transverse paths that connect the parallel paths to each other.

17. A pilot valve assembly according to claim 16, further comprising:

a variable flow restrictor disposed in the internal flow network.

18. A pilot valve assembly according to claim 16, further comprising:

a variable restrictor disposed in one of the transverse paths.

19. A pilot valve assembly according to claim 16, further comprising:

a check valve disposed in the internal flow network.

20. A pilot valve assembly according to claim 16, further comprising:

a check valve disposed in one of the transverse paths.

Background

A pressure regulator may be used to control the downstream pressure of the fluid. Facilities in the natural gas market typically employ pressure regulators to manage the flow of high pressure fuel gas through pipelines. However, these applications can present significant design challenges because the operator requires the device to have the proper capacity, accuracy, and response time, and also minimizes control changes that can be caused by changes in inlet pressure, rapid changes in downstream demand, or temperature effects on internal components.

Disclosure of Invention

The presently disclosed subject matter relates to improvements to pressure regulators that address these challenges. Of particular interest are embodiments of modular guide assemblies that can be used to adjust the performance of the pressure regulator. These embodiments employ designs that provide superior control for high precision operation of an associated pressure regulator. As an additional benefit, the expandable design avoids extensive rework or manufacturing of new parts to suit the needs of different applications. This feature makes the design particularly attractive for use in work monitor systems or those systems that deploy multi-stage pressure regulation, as the modular pilot assembly can be expanded to add additional pilot (or pilot valve).

As mentioned above, pressure regulators play an important role in fluid delivery systems. These devices accurately maintain the flowing fluid at a particular desired pressure. For many industrial applications, pressure regulators must be of a particularly robust or robust design to withstand high pressures, harsh environments, or simply provide reliable, durable operation. These designs may require configurations (e.g., materials, fastening techniques, etc.) that are particularly expensive or time consuming to manufacture or construct according to specifications. This configuration may utilize a spring operated valve that opens and closes in response to changes in downstream demand. Nominally, the valve has an "equilibrium" position that maintains equal pressure on both the upstream and downstream sides of the device. From this position, the valve opens to allow fluid to flow through the device, thereby maintaining the downstream pressure at a relatively constant level (typically in response to an increase in downstream demand). The valve moves to reduce flow as demand decreases, often eventually reaching its equilibrium position again. In some applications, the valve may have a fully "closed" position that completely prevents fluid flow. The proposed design allows for a better, more accurate downstream pressure in response to demand. It also increases the operating pressure of the pressure regulator to accommodate applications where the inlet pressure is at least 1500 PSI.

Drawings

Referring now briefly to the drawings, wherein:

FIG. 1 shows a schematic diagram of an exemplary embodiment of a pressure regulator;

FIG. 2 shows a perspective view of an exemplary construction of the pressure regulator of FIG. 1;

FIG. 3 shows a front view in cross-section of the pressure regulator of FIG. 2;

FIG. 4 shows a perspective view of the pressure regulator of FIG. 2 in partially exploded form;

FIG. 5 shows a perspective view of the pressure regulator of FIG. 2 in partially exploded form;

FIG. 6 shows a perspective view of the pressure regulator of FIG. 2;

FIG. 7 shows a perspective view of an example of the manifold of FIG. 2;

FIG. 8 schematically illustrates a front view of a cross-section of the pressure regulator of FIG. 6 in a first position;

FIG. 9 schematically illustrates a front view of a cross-section of the pressure regulator of FIG. 6 in a second position;

FIG. 10 shows a perspective view of a work monitor system incorporating a pressure regulator of the type described herein;

FIG. 11 schematically illustrates a front view in cross-section of the system of FIG. 10 with the pressure regulator in a first position; and is

Fig. 12 schematically illustrates a front view in cross-section of the system of fig. 10 with the pressure regulator in a second position.

Wherever applicable, like reference numerals designate identical or corresponding parts and units throughout the several views, and unless otherwise specified, the views are not drawn to scale. Embodiments disclosed herein may include elements that appear in one or more of the several views or in a combination of the several views. Moreover, the methods are merely exemplary and may be modified by, for example, reordering, adding, deleting, and/or changing the various stages.

Detailed Description

Manufacturers often take advantage of opportunities to improve the configuration of industrial equipment. These opportunities may lead to better, more reliable devices or provide new functions or features thereon. In many cases, these improvements may also lead to innovative solutions that achieve savings in terms of lower cost components, labor, and assembly or maintenance and repair.

The following discussion describes various embodiments of modular guide assemblies for use on pressure regulators. The guide assembly herein incorporates several design features to provide better, more accurate control than known devices. The expandable manifold allows the pilot assembly to add additional pilot valves in series. The manifold may also incorporate an internal variable orifice to help tune the response time of an associated pressure regulator. The design is also compatible with other types of flow control devices, such as control valves. Other embodiments and configurations are within the scope of the subject matter herein.

Fig. 1 shows a schematic diagram of an exemplary embodiment of a pressure regulator 100. This embodiment is shown as part of a gas distribution system generally identified by the numeral 102. The system 102 may include a pipe 104 carrying a material 106. As also shown, the pressure regulator 100 may include a flow controller 108 having balanced trim 110 and an actuator 112. The control system 114 may be coupled with the actuator 112. The control system 114 may include a fluid circuit 116 having a directing unit 118 that controls the limited flow feed of the material 106 to the actuator 112.

Broadly speaking, the pressure regulator 100 may be configured for use in applications having high inlet pressures. These configurations may integrate a pilot valve such that the "sensed pressure" (or downstream pressure) is registered at both the actuator and the pilot valve. Such an arrangement may prove useful for better and highly accurate pressure control downstream of the device. In addition, the device incorporates a balanced pressure plug that provides bubble-tight closure over a wide range of pressure differentials.

The gas distribution system 102 may be configured for material transport to an industrial site or a portion of a larger network. These configurations may be used in facilities that process or distribute hydrocarbons, such as natural gas or "fuel gas. Cities and utilities may deploy complex networks to deliver resources to consumers, including residential and commercial fuel gas customers. All of these networks may contain a variety of means for regulating flow, including a pressure regulator 100. These devices may be installed in series with the conduit 104, which may embody a high volume conduit capable of carrying high pressure fluids. However, in addition to fluids (e.g., liquids and gases), material 106 may also comprise solids and solid/fluid mixtures.

The flow controller 108 may be configured to regulate the flow of the fuel gas 106 through the pressure regulator 100. These configurations may be embodied as valves that operate in response to a pressure differential across their inlets and outlets. This feature matches the flow rate of the fuel gas 106 to, for example, demand on the network 102. As described above, a valve may have various operating positions or conditions to manage flow. One location may maintain pressure balance across the upstream or "supply" side and the downstream or "demand" side of the device. The position may change in response to changes in downstream demand. An increase in downstream demand, for example, may lower the downstream pressure and move the valve to a position that allows more fluid flow. The resulting flow meets the downstream demand. When the pressure is equalized, the valve may move back to its previous "equilibrium" position. In one implementation, the valve may employ a fail-close design that causes the valve to default to a "fully closed" position in response to a pressure loss, mechanical failure, or other problem on the control device or in the network 102. This position completely prevents gas flow through the device.

The balanced trim 110 may be configured to accommodate the higher inlet pressure on the upstream side of the valve. These configurations may include a plug (or closure member) that moves relative to a seat (to instantiate the variable position of the valve described above). For a "balanced" trim design, the fluid forces are balanced on either side of the plug at equilibrium. To this end, the plug may incorporate openings or similar design features. The openings can vent fluid from the upstream side of the plug into the chamber where the pressure regulator 100 is "above" or on the opposite side of the plug.

The actuator 112 may be configured to adjust the position of the plug relative to the seat. These configurations may embody devices (or mechanical elements) that may apply a load on the plug. Examples of mechanical devices may include diaphragms that are sensitive to pressure changes. A spring may be used to provide a spring force that supplements the diaphragm. For a failed closure device, the spring force will direct the plug to its fully closed position.

The control system 114 may be configured to apply a gain to the system. These configurations may be embodied as devices that multiply small changes in downstream pressure to larger changes at, for example, the diaphragm. These devices improve response time and provide stable, accurate control of valve position in response to changes in downstream demand.

The fluid circuit 116 may be configured to direct the fuel gas 106 between components of the control system 114. These configurations may utilize a local network of conduits (or pipes or tubing). The conduit may extend from a location or tap on the pipe 104 that is present on both the upstream and downstream sides of the pressure regulator 100. These taps allow fuel gas 106 to enter the conduit. The fuel gas 106 is delivered to the actuator 112 through a local network and through a control system 114.

The pilot unit 118 may be configured to regulate the pressure to the actuator 112. These configurations may be embodied as a device (or "pilot") having a manifold that houses a valve (or "pilot"). For two-way control, the conduit may couple the pilot valve with the actuator 112 in order to achieve a gain that enhances the response of the plug to changes in downstream demand (or the movement of the plug relative to the seat in response). The manifold may have an internal flow path that places a plurality of pilot valves in flow connection with each other to allow fuel gas 106 to flow between them. The pilot valve may be of a design for a fixed or variable pressure differential, as desired. This design may allow any number of pilot valves (and other devices, such as check valves or orifices) to be incorporated into a single unit on the pressure regulator 100. In one implementation, the manifold has a modular design with various components that mate or attach together. This arrangement may accommodate a combination of fixed and variable pilot valves to match any proposed application of the pressure regulator 100 or to allow an end user to effectively tune the performance of the pressure regulator 100 as desired.

FIG. 2 illustrates a perspective view of one example of the pressure regulator 100 of FIG. 1. For clarity, components that contain components of the instantiated control system 114 are not shown in this example. The device may have a robust design of the housing 120, which is typically made of cast or machined metal to make the device compatible with high pressures and caustic, harsh, or corrosive materials (e.g., fuel gas 106). The housing 120 may have several parts or members, shown here as including a pair of cylindrical members (e.g., an upper cylindrical member 122 and a lower cylindrical member 124) and a joint member 126. The housing members 122, 124, 126 may mate with one another at a peripheral outer flange 128. The aperture 130 may fill the exterior of one or more of these components. Some of the bores 130 may operate as ports 132 with threaded openings to accommodate fluid fittings, as noted in more detail below. The other holes may operate as threaded holes 134 in a mounting area 136 that receives a component of the guide unit 118, for example. In one implementation, the housing 120 may include a valve body 138 that houses the balanced trim 110 described above in FIG. 1. The valve body 138 may have openings 140 at either end of an internal passage 142. The flange 144 (or butt-welded end) may allow the valve body 138 to be installed in series with a section of the pipe 104. In one example, the valve body 138 may include a port 146 that may also have a threaded opening to receive a fluid fitting.

FIG. 3 illustrates a pressure regulator taken at line 3-3 of FIG. 2100 in cross-section. The cylindrical members 122, 124 may form an interior chamber 148 that encloses components of the actuator 112. These components may include a diaphragm 10, preferably an annular disk of flexible material including metal, rubber, or composite material. The annular disc 10 may be arranged with its outer peripheral portion "sandwiched" between peripheral outer flanges 128 of the cylindrical members 122, 124. This arrangement divides the interior chamber 148 into two chambers (e.g., a first chamber 150 and a second chamber 152). The ports 132 in the housing members 122, 124 may form flow channels extending to each of the chambers 150, 152. Additional components of the actuator 112 may include support plates 12, 14 residing on either side of the annular disc 10. The compression spring 16 may reside in a first or "upper" chamber 150 to apply a force to the upper support plate 12. In the second or "lower" chamber 152, the sealed bundle 18 may be inserted into an opening 154 in the barrel member 124. The seal pack 18 may have an annular body 20 with an outer seal 22, such as an O-ring, residing in a groove. The annular body 20 may also have centrally located through-holes to receive inner seals (e.g., first inner seal 24 and second inner seal 26) and a bushing 28. The plate 30 may reside on top of the ring body 20. Fastener F₁The annular body 20 and plate 30 may be penetrated into the barrel member 124. Additional seals 32, 34 may be used to seal any gaps between the barrel member 124 and the fitting 126 and the interface between the fitting 126 and the valve body 138. As also shown, the device may include a valve stem 36 that is axially movable through the seals 24, 26 and the bushing 28. This movement may be caused by a change in demand downstream of the pressure regulator 100. One end of the valve stem 36 may be coupled to the diaphragm 10. The indicator 38 may be coupled to the end, for example, using a magnet (although other fastening techniques are readily acceptable). The indicator 38 may penetrate through the upper barrel member 122 into the indicator housing 40, which forms a seal with the upper barrel member.

The other end of the stem 36 may reside in the valve body 138 along with other components that balance the trim 110. These components may reside in the chamber 156. In one implementation, the balanced trim may include a retainer 42, shown here as having an opening 46 circumferentially disposed in a peripheral wall thereofAn empty cylinder 44. The plug 48 may reside in the cage 42. As described herein, the plug 48 may be configured for inlet pressure to equalize on either side. These configurations may utilize, for example, a bifurcated design of first plug member 50 having an elongated portion that extends into second plug member 52. The elongated portion may receive an end of the valve stem 36. Openings 54 in plug members 50, 52 may allow pressure to equalize across furcation plug 48. Annular seal 56 may reside in a peripheral groove around the exterior of second plug member 52. An example of the annular seal 56 may utilize a rubber ring (with a plastic support ring if desired). The rubber ring 56 may contact the inner surface of the peripheral wall on the cylinder 44. This arrangement creates a circumferential seal around the inner surface (and the outer surface of the second plug member 52). In one implementation, the plug 48 may incorporate a gasket 58 that resides between the plug members 50, 52, such asOr a nitrile ring. A portion of the seal 58 may engage the seat 60 to achieve the fully "closed" position of the plug 48.

Fig. 4 and 5 illustrate the pressure regulator 100 of fig. 2 in partially exploded form. Fastener F₂The fitting member 126 may be secured to the valve body 138. Fastener F₃The barrel members 122, 124 may be secured together to form an "actuator barrel" 158. Fastener F₄May be inserted through each of the barrel members 122, 124 to secure the actuator barrel 158 to the adapter member 126. Notably, this arrangement forms a modular structure that allows an end user to perform maintenance and repair in its installed or "in-line" position of the pressure regulator 100 on the pipe 104. In FIG. 4, end-user removable fastener F₄To disengage the actuator cylinder 158 from the joint member 126. The end user may lift the actuator cylinder 158 off of the fitting 126. This action also removes the components that balance the trim 110 (i.e., the plug 48 as a whole) from the valve body 138. As best shown in FIG. 5, the end user removable fastener F₃、F₄To disengage the upper cylindrical member 122 from the lower cylindrical member 124. The end user may lift the upper cylindrical member 122 offThe partial cylindrical member 124 to access an interior chamber 148 formed by the cylindrical members 122, 124. This feature may allow an end user to service the diaphragm 10 without disturbing other components, including the seals 32, 34 (FIG. 3) or the balanced trim 110 (FIG. 3). In one implementation, the end user may also remove the septum 10 to access (and replace) the sealed bundle 18 (fig. 3).

FIG. 6 illustrates a perspective view of one example of the pressure regulator 100 of FIG. 3. Components have been added to each component to continue the discussion of certain features and functions of the proposed design. For example, conduits 160 in the form of metal tubing may extend between fluid fittings 162 to complete fluid connections between components of the pressure regulator 100, as well as between these components and locations on the pipe 104 upstream and downstream of the pressure regulator 100. In some implementations, filter F_LMay also be installed in the fluid circuit 114. The guide unit 118 may include an engagement block 164 to secure the manifold 166 to the joint member 126 (at the mounting region 136). The manifold 166 may be embodied as a pair of ported blocks (e.g., a first ported block 168 and a second ported block 170). As described above, the configuration of the manifold 166 may allow for changes to the guide unit 118 to expand the functionality. For example, the blocks 168, 170 may be separated from one another to add components to the manifold 166 that adapt the pressure regulator 100 to a particular application, e.g., as part of a work monitor arrangement, etc.

Fig. 7 depicts a perspective view of an example of the guide unit 118 to illustrate this concept. In this example, the manifold 166 includes a third ported block 172. Examples of ported blocks 168, 170, 172 may be embodied as separate elements of the manifold 166, such as a machined metal blank, e.g., aluminum, steel, or a steel alloy. The blank may contain an opening 174, which may be embodied as a gap or a threaded hole. The bore 174 may receive a fastener F₅To secure the ported blocks 168, 170, 172 together. This arrangement facilitates a modular design of the manifold 166. As also shown, the ported blocks 168, 170, 172 may have an external access port 176 that provides a threaded opening to receive the fitting 162 (fig. 6).

FIG. 8 schematically showsThere is shown an elevation view of a cross-section of the pressure regulator 100 taken at line 8-8 of fig. 6. The conduit 160 may include a manifold 166 and an inlet or supply side P₁Supply line SUP of the connection₁. Sensing line S₁And S₂The upper chamber 150 of the actuator cylinder 158 may be connected to the outlet or demand side P, respectively₂And to the manifold 166. Load line L₁A manifold 166 may be coupled with the lower chamber 152 of the actuator cylinder 158. Also as shown, the ported blocks 168, 170 may have an internal flow network 178, typically a machined bore (or similar feature), that allows fluid to flow between various flow controllers that allow a technician to more accurately tune the set point of the pressure regulator 100. Examples of flow controllers include an adjustable orifice 180 and a check valve 182. The adjustable orifice 180 or "restrictor" may have a V-shaped groove on its outer surface. A threaded plug 184 may be used to seal one or more of the access ports 176. In one implementation, the flow controller may also include a pair of pilot valves (e.g., a first pilot valve 186 and a second pilot valve 188). The first pilot valve 186 may have a fixed pressure differential. The second pilot valve 188 may be configured (e.g., with a knob) to adjust the pressure differential across the device. The end user may tune the operation of the guide unit 118 by adjusting the variable guide 188 or rotating the adjustable orifice 180 to change the radial orientation of the V-groove relative to the internal flow path 178 in the second band port block 170. The value of the fixed pressure differential of the first pilot valve 186 may be adapted to the design parameters of the second pilot valve 188; exemplary values may range from 50psi to 100 psi.

The flow restrictor 180 may be configured to work in conjunction with a second or "primary" pilot valve 188 to define the pressure in the lower chamber 152. In one implementation, the primary pilot valve 188 may have an internal orifice that increases and decreases in size in response to changes in downstream pressure. The orifice expands in response to a downstream pressure below the set point of the pressure regulator 188. When the orifice becomes larger than the orifice of the flow restrictor 188, more gas flows into the lower chamber 152 than through the flow restrictor 188 and downstream (through the upper chamber 150). The orifice constricts in response to the downstream pressure being above the set value, such that when it is smaller than the orifice of the flow restrictor 100, less gas will flow to the lower chamber 152 (than downstream). The end user may adjust the size of the orifice of the flow restrictor 188 to manage the relationship between the internal orifice and the orifice of the flow restrictor 188, and in turn tune the response accuracy and speed of the pressure regulator 100.

The check valve 182 may be configured to limit the pressure differential across the diaphragm 10. These configurations may prove useful in preventing damage (to the diaphragm 10) that may be caused by back pressure or related use cases. The back pressure may occur at startup because if the downstream pressure rises rapidly, the gas may flow into the upper chamber 150 faster than it is discharged through the flow restrictor 180. This imbalance creates pressure in the upper chamber 150. The check valve 182 may open in response to a downstream pressure above the cracking pressure to allow more gas to pass to the lower chamber 152, allowing the pressure to equalize across the diaphragm 10.

The diagram of fig. 8 shows the pressure regulator 100 in a first position. The position and the supply side P₁The supply side and the demand side P are in agreement with the pressure of the fuel gas 106₂Pressure balance (or phase balance) of the fuel gas 106. The diaphragm 10 (and spring 16) exerts a spring force that maintains the position of the balanced plugs 50, 52. As described herein, while the plugs 50, 52 are shown in contact with the seat 60, this is not always the case. Supply side pressure P₁Acting on each side of the balanced plugs 50, 52 and simultaneously on one side of the pilot valves 186, 188. Demand side pressure P₂Through the sensing line S₁Acting on the chambers 150, 152 and through the load line L₁And a sensing line S₂Acting on opposite sides of the pilot valves 186, 188.

FIG. 9 also schematically illustrates a front view of a cross-section of the pressure regulator 100 taken at line 8-8 of FIG. 6. The figure shows the pressure regulator 100 in a second position. The position reflects the demand-side pressure P₂A change in (c). This change generally corresponds to an increased demand, which may result in a lower side pressure P₂Rapidly drops below the supply side pressure P₁. In response to a sensed Differential Pressure (DP)_1,2) First, aThe pilot valve 186 operates to direct the supply side pressure P at the second pilot valve 188₁Reduced or "stepped down" to a lower intermediate pressure P₃. Second pilot valve 188 responsive to intermediate pressure P₃And opens to increase or "step up" the pressure in the lower chamber 152 to the loading pressure P₄The loading pressure is high enough to overcome the spring force and move the balanced plugs 50, 52 from their first positions (in fig. 8). The new position of the balanced plugs 50, 52 allows the fuel gas 106 to pass through the openings 46 in the cage 44 to meet downstream demand. In one implementation, the balanced plugs 50, 52 may return to the first position because the pressure is at the supply side pressure P₁And a demand side pressure P₂Balance between them.

FIG. 10 shows a perspective view of a pair of flow controllers of the type discussed with respect to the pressure regulator 100 described above. These flow controllers form a "work monitor" arrangement in which a first or "first stage" regulator a and a second or "second stage" regulator B are connected in series on the conduit 104. On the first stage regulator a, the manifold 162 contains ported blocks 164, 166, 168 to accommodate a third pilot valve 190, which is preferably configured to vary the pressure differential across the device.

Fig. 11 schematically illustrates a cross-sectional front view of the pressure regulator A, B taken at line 11-11 of fig. 10. The figure identifies the pilot valves as pilot 1 and pilot 2 on the first stage adjuster a and pilot 3 on the second stage adjuster B. The conduit 174 may comprise a supply line SUP₂Which couples the manifold 162 on the second stage regulator B to the intermediate section of conduit 104 extending between the pressure regulators A, B. Sensing line S₃And S₄The upper chamber 150 on the first stage regulator a may also be coupled with the middle section of the conduit 104. Load line L₂Manifold 162 may be coupled with lower chamber 152 on the first stage regulator. Also as shown, sensing line S₅Connecting the third ported block 168 with the demand side P₂Coupled to monitor the second stage regulator B.

The diagram of fig. 11 shows the pressure regulator A, B in a first position. The diaphragm 10 (and spring 18) is under two pressuresThe force regulator A, B exerts a spring force on it that maintains the position of the balanced plugs 50, 52, which may or may not cause the plugs 50, 52 to contact the seat 60. The position can reflect the supply side P₁Pressure and demand side P of fuel gas 106₂Or pressure equilibrium (or phase equilibrium) condition of the fuel gas 106. However, when fully closed, the upstream and downstream pressures may be different, but there will be no flow through one or both of the devices. Moving from left to right in the figure, the supply side pressure P₁Acting on each side of the balanced plugs 50, 52 and simultaneously on the fixed pilot 186 on the first stage adjuster a and one side of the pilot 1. Loading pressure P₄Through the sensing line S₃Acting on the chambers 150, 152 and through the sensing line S₄And a load line L₂Acting on the fixed pilot 186 and on opposite sides of the pilot 1 and pilot 2. Downstream pressure P₂Through the sensing line S₅Acting on the leader 2. On the second stage regulator B, the load pressure P₄Through the supply line SUP₂Acting on both sides of the balance plugs 50, 52 and on one side of the fixed pilot 186 and the pilot 3. Demand side pressure P₂Through the sensing line S₁Acting on the chambers 150, 152 and through the load line L₁And a sensing line S₂Acting on opposite sides of the pilot valve 178 and the pilot 3.

FIG. 12 also schematically illustrates a cross-sectional front view of the pressure regulator 100 taken at line 11-11 of FIG. 10. The graph shows that the demand side pressure P is reflected₂In the second position, pressure regulator A, B. Moving again from left to right in this figure, the fixed pilot 186 on the first stage regulator A operates to regulate the supply side pressure P₁Reduced to a lower intermediate pressure P₃. The pilot 1 and the pilot 2 are responsive to an intermediate pressure P₃And operates to gradually reduce the pressure in the upper chamber 150 to less than the loading pressure P₄Inter-stage pressure P of₅Thereby moving the plugs 50, 52 from their first positions (in fig. 11). In response to a sensed Differential Pressure (DP)_2,5) The fixed pilot valve 186 on the second stage regulator B will direct the interstage pressure at the pilot 3P₅Gradually reduced to a lower intermediate pressure P₃. The pilot 3 being responsive to intermediate pressure P₃And opens to increase or "step up" the pressure in the lower chamber 152 to the loading pressure P₄The loading pressure is high enough to overcome the spring force and move the balanced plugs 50, 52 from their first positions (in fig. 11). The new position of the balanced plugs 50, 52 allows the fuel gas 106 to pass through the openings 46 in the cylinder 44 to meet downstream demand. In one implementation, the balanced plugs 50, 52 on the pressure regulator A, B may return to the first position because the pressure is at the supply side pressure P₁And a demand side pressure P₂Balance between them.

This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. An element or function recited in the singular and proceeded with the word "a" or "an" should be understood as not excluding plural said elements or functions, unless such exclusion is explicitly recited. Reference to "one embodiment" of the claimed invention is not to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features. Furthermore, the claims are only a few examples of how the patentable scope of the invention may be defined. This range may encompass and contemplate other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.

The examples presented below include certain elements or clauses, one or more of which may be combined with other elements and clauses, describing embodiments contemplated within the scope and spirit of the disclosure.