Using pressure to monitor the position of components on a control valve

Abstract

A position monitoring system is configured for use on valves and other flow controls. The configurations include a motion sensitive unit, such as a flexible tube with an end that can move with a valve stem on a flow control. The flexible tube can contain synthetic oil. The other end of the tube can be coupled to a pressure sensor. In use, the sensor can generate a signal corresponding to the discharge pressure of the synthetic oil in the tube. Operating hardware on the flow control, such as processing hardware that is part of a valve positioner or controller, can process the signal from the pressure sensor to identify the operating condition of the valve, such as the position of the closure member of the valve.

Description

Background Technology

[0001] Flow controls play a crucial role in many industrial facilities. For example, power plants and industrial process facilities use different types of flow controls to manage the flow of materials (typically fluids) across vast networks of pipes, tanks, generators, and other equipment. Control valves are a type of flow control that operators often use to regulate the flow of materials on their production lines. These devices can be implemented using various systems to precisely monitor the position of certain parts to keep flow rates within limits that meet process parameters. Examples of these systems include mechanical linkages or other mechanical devices that trigger optical or magnetic sensors. However, industry trends tend to dislike linkages because they increase the cost and complexity of the entire facility. The facility is also sensitive to vibrations prevalent in industrial environments. Summary of the Invention

[0002] The subject matter of this disclosure generally relates to improvements in position monitoring on control valves and flow controls. Of particular interest are implementation schemes for monitoring the position of parts on flow controls using pressure-based devices. These schemes can forgo conventional mechanical linkages and instead utilize "discharge pressure" in the fluid column. This type of feedback can be beneficial to designs because it is less susceptible to environmental conditions that the flow control may be exposed to in the field, including vibrations present in many industrial environments. Attached Figure Description

[0003] This instruction manual refers to the following figures:

[0004] Figure 1 A schematic diagram illustrating an exemplary embodiment of the location monitoring system 100 is provided.

[0005] Figure 2 Depicting Figure 1 A schematic diagram of an example location monitoring system;

[0006] Figure 3 Depicting Figure 1 A schematic diagram of an example location monitoring system;

[0007] Figure 4 Depicting and Figure 1 A front view of an example flow control used in a location monitoring system;

[0008] Figure 5 Depicting Figure 4 A sample front view of the flow control;

[0009] Figure 6 Depicting Figure 4 The side view of the flow control; and

[0010] Figure 7 Depicting and Figure 1 A perspective view of an example valve positioner used in a position monitoring system.

[0011] The accompanying drawings and any descriptions herein represent examples that disclose or explain the invention. These examples include best practices and also enable any person skilled in the art to practice the invention, including making and using any apparatus or system and performing any combined methods. Unless otherwise stated in the discussion, the drawings are not drawn to scale. Elements in the examples may appear in one or more views or in a combination of views. The same reference numerals may be used in the drawings to denote the same or corresponding elements. The methods are merely exemplary and may be modified by, for example, reordering, adding, deleting, and / or changing individual steps or stages. Such stages and any parts, components, elements, or functions may be identified in the singular form of the words “a” or “an”; however, this should not exclude any plural form of such names unless such exclusion is expressly stated or indicated in the description. Similarly, any reference to “an embodiment” or “an implementation” does not exclude the existence of additional embodiments or implementations that also incorporate the described features. Detailed Implementation

[0012] The features of the examples shown in the above figures will now be discussed. These features eliminate the need for certain mechanical linkages that provide feedback to control setpoints on control valves and similar flow controls. These linkages are susceptible to inaccuracies, often caused by vibrations prevalent in industrial environments where flow controls are present in the field. In contrast, the design proposed herein utilizes “mechanical-free” modes to measure or monitor the position of critical components on the device. These modes generate more accurate data that operators can rely on to manage process parameters on their network. Other embodiments are within the scope of this disclosure.

[0013] Figure 1 An example of a position monitoring system 100 is depicted. This example exists in a distribution network 102, which is typically designed to transport material 104 through a network of conduits 106. The position monitoring system 100 may be connected to a flow control 108 as part of the network 102. The flow control 108 may have a valve 110 with a valve body 112. A closing member 114 and a support 116 may be housed within the valve body 112. A valve stem 118 may couple the closing member 114 to an actuator 120. A controller 122 may be coupled to the actuator 120. In one embodiment, the position monitoring system 100 may include a motion-sensitive unit 124 coupled to the valve stem 118. A sensor unit 126 may be coupled to the motion-sensitive unit 124 and the controller 122.

[0014] In a broader sense, the position monitoring system 100 can be configured to maintain fluid flow to meet process parameters. These configurations may include devices that do not require moving parts, such as linkages, to measure the position or location of parts on valves or similar flow controls. These devices can replace the use of fluid characteristics or parameters such as pressure to generate accurate data corresponding to the operating conditions on the flow control. This feature is useful because it simplifies the construction of the entire component, which reduces manufacturing, labor, and maintenance costs, and potentially makes the flow control operate more accurately to meet process parameters.

[0015] Distribution system 102 can be configured to deliver or move these fluids. These configurations can manifest as large-scale infrastructure. Material 104 may also include gas, liquid, solid-liquid mixture, or liquid-gas mixture. Conduit 106 may include pipes or lines that are often connected to pumps, boilers, etc. Conduit 106 may also be connected to tanks or storage containers. In many facilities, this equipment forms complex networks to perform processes such as refining raw materials or manufacturing final products.

[0016] Flow control 108 can be configured to regulate the flow rate of material 104 through conduits 106 in these complex networks. These configurations may include control valves and similar devices. The valve body 112 in such devices is typically made of cast or machined metal. This structure may form flanges at openings I, O. Adjacent conduits 106 may be connected to these flanges to allow material 104 to flow through the device, for example, through openings in support 116. Closure member 114 may be embodied as a disc or “plug.” Valve stem 118 may be embodied as an elongated cylinder or rod with one end connected to the plug. The other end of the rod may be coupled to actuator 120. In one embodiment, actuator 120 may include a piston and spring (or multiple springs) that together generate a load acting on valve stem 118. However, in some designs, it is not uncommon for a flexible diaphragm to replace the piston. In use, this load regulates the position of closure member 114, which in turn manages the flow of material 104 through support 116 into conduit 106 downstream of the device.

[0017] Controller 122 can be configured to process and generate signals. These configurations can be connected to a control network (or “distributed control system” or “DCS”). This network maintains the operation of all units on the production line to ensure that material flows according to the process or meets certain process parameters. The DCS can generate control signals with operating parameters that describe or define the operation of flow control 108 for this purpose. The operating hardware in controller 122 can take the form of electrical and computing components (e.g., processor, memory, executable instructions, etc.). These components may also include an electro-pneumatic device that operates the incoming pneumatic supply signal P1. These components ensure that the actuator control signal P2 output to actuator 120 is adapted for flow control 108 to supply material 104 downstream according to process parameters.

[0018] The motion-sensitive unit 124 can be configured to provide feedback corresponding to the position of the closing member 114. These configurations may include devices with few (if any) moving parts. These devices may instead utilize non-contact modal or similar "mechanical-free" techniques. In one embodiment, these techniques may correlate the discharge pressure of the fluid column with the position or location of the closing member 114.

[0019] Sensor unit 126 can be configured to generate data corresponding to the discharge pressure. These configurations may include sensors sensitive to small pressure variations, such as those on the order of mmWC / mbar. These sensors can generate a signal S1 corresponding to the pressure value. Operating hardware in controller 122 can then process this signal to generate data identifying the position of closing member 114. In one embodiment, the operating hardware may take into account environmental conditions surrounding the device. These conditions may include ambient temperature or ambient pressure, changes of which may affect the various components of motion-sensitive unit 124.

[0020] Figure 2 Depicting Figure 1A schematic diagram of an example of a position monitoring system 100. Units 124, 126 may include conduits 128, such as tubes 130 made of flexible rubber, plastic, or other materials that meet certain design requirements such as bending radius R or diameter (e.g., 4 mm to 12 mm). Tube 130 may contain fluid 132, such as synthetic oil or similar compounds with similar properties; however, this disclosure contemplates that fluid 132 may include materials or compositions of various densities, viscosities, or other properties. Fluid 132 may not fill the interior of tube 130, leaving an air gap G. Also as shown, a first end of tube 130 may be coupled to a pressure sensor 134, such as an "ultra-low range pressure" sensor discussed herein. A connector 136 may couple a second end of tube 130 to a valve stem 118. This feature allows the second end of tube 130 to move simultaneously with the valve stem 118. The design for connector 136 may also include materials or devices for isolating or suppressing vibrations of tube 130. This design can benefit from the use of braided connectors or quick-connect tubing connectors on sensor 134 or connector 136 to facilitate assembly and use on industrial valves.

[0021] Figure 2 The layout of the position monitoring system 100 can provide information about valve 110 ( Figure 1 Accurate feedback on the operating status of the valve 110. In one embodiment, an "ultra-low range pressure sensor" 134 can generate a signal S1 that defines the value of the discharge pressure in the fluid column 132 within the tube 130. The signal S1 can change in response to a change in the position of the second end of the flexible tube 130, which can occur in response to a movement M of the valve stem 118, for example, moving up or down as needed to set the position of the closing member 114 relative to the support 116 to achieve the set point of the flow control 108. The controller 122 can process the signal S1 to generate a value for the position of the closing member 114 or other indicators of the operating status of the valve 110 (e.g., "open percentage" or "open %").

[0022] Figure 3 Depicting Figure 1 A schematic diagram of another example of the position monitoring system 100. A connector 136 secures a cylinder 138 to a valve stem 118. The cylinder 138 may form a reservoir 140 with an opening 142. As shown, a second end of the tube 130 may be connected to the cylinder 138 at the opening 142, for example, at a protrusion or other feature that can receive the tube 130. Fasteners such as clamps or fittings may be used to achieve this. The arrangement of the tube 130 at the opening 142 allows fluid 132 to completely fill the tube 130, with excess fluid residing in the reservoir 140. In one embodiment, a piston 144 may be fitted inside the cylinder 138. The piston 144 may have a fixed end 146, shown here as being attached to an actuator 120.

[0023] Figure 3 The layout of the position monitoring system 100 can provide information about valve 110 ( Figure 1 Accurate feedback on the operating status of the valve 110. In one embodiment, the cylinder 138 can move simultaneously with the valve stem 118, and subsequently relative to the piston 144. This feature can increase or decrease the pressure applied by the piston 144 to the fluid 132 in the reservoir 140. As described above, the "ultra-low range pressure sensor" 134 can generate a signal S1 corresponding to the pressure value of the fluid column 132 in the pipe 130. The controller 122 can process the signal S1 to generate a value for the position of the closing member 114 or other indicators related to the operating status of the valve 110 (e.g., "open percentage" or "open %").

[0024] Figure 4 and Figure 5 A front view depicting an exemplary structure of flow control 108 is shown. This structure may include an upper structure 148 forming a bracket 150 with a first end 152 attached to a valve body 112. A second end 154 of the bracket 150 may support an actuator 120, shown herein as having an upper housing 156 and a lower housing 158. Housings 156, 158 may be secured to each other around a peripheral flange 160. Fasteners F (such as nuts and bolts) may be used to tighten the flange 160 of housings 156, 158 to form a sealed hermetically sealed device. Figure 4 Examples also include those for location monitoring system 100 Figure 2 An example of a connector arrangement structure. Figure 5 Provided for location monitoring system 100 Figure 3 An example of the position of the piston / cylinder arrangement structure on the structure of flow control 108.

[0025] Figure 6 Depicting Figure 4 and Figure 5 A side view of an exemplary flow control 108. A manual device 162, such as a wheel or lever, may be attached to the bracket 150. This device allows the end user to manually move the closing member 114 as needed. In one embodiment, the controller 100 may be embodied as a valve positioner 164 attached to the bracket 150. The valve positioner 164 may have a housing 166 to house or enclose operating hardware or other working components. The housing 166 may be explosion-proof or designed to at least meet certain intrinsic safety requirements. In one embodiment, a pressure sensor 134 may reside outside the housing 166, for example, as a separate unit attached to the housing 166 or the bracket 148. However, in other embodiments, the sensor 134 may reside inside the housing 166.

[0026] Figure 7 A perspective view depicting an exemplary structure of a valve positioner 164 in exploded form is shown. The structure may include a manifold having a manifold body 168, which is typically machined or formed from metal, plastic, or composite material. The device may include one or more plates 170 having processing hardware disposed on the plates. Other hardware may include a pneumatic module 172, which may include a current-to-pressure transducer and a relay. These devices may generate an actuator control signal P2 (…) delivered by the valve positioner 164 to the actuator 120. Figure 1 As also shown in the figure, in this example, housing 166 may include covers 176, 178. Cover 176 may be secured to manifold body 168 to protect control components, including plate 170, from environmental conditions prevalent around flow control 108. Cover 178 may include display 180 and button input device 182, which may serve as the primary local user interface, allowing end users (e.g., technicians) to interact with valve positioner 164. This feature may be important for performing routine maintenance, configuration, and setup, for example, to allow end users to exit valve operating mode and navigate through menu structures to manually perform functions such as calibration, configuration, and monitoring. In one embodiment, the structure may also include one or more meters 184, 186 that provide indications of fluid flow conditions (e.g., pressure, flow rate, etc.) used by valve positioner 164 to operate flow control 108.

[0027] This specification may include and envision other examples that would occur to those skilled in the art. Such other examples fall within the scope of the claims if they have structural elements that are indistinguishable from the literal language of the claims, or if they comprise equivalent structural elements that are not substantially different from the literal language of the claims.

Claims

1. A control valve, the control valve comprising: Actuator; A valve stem, which is connected to the actuator; A closing member, which is connected to the valve stem; and A position monitoring system is connected to the closure member and is configured to generate a signal in response to the discharge pressure of the fluid, the signal corresponding to the position of the closure member.

2. The control valve according to claim 1, wherein, The location monitoring system includes a tube that contains the fluid.

3. The control valve according to claim 1, wherein, The position monitoring system includes a tube containing the fluid, the tube being configured with an end that moves in response to movement of the valve stem.

4. The control valve according to claim 1, wherein, The location monitoring system includes: A pipe and a connector, the pipe containing the fluid, the connector connecting a first end of the pipe to the valve stem, and A pressure sensor is connected to the second end of the tube and is configured to generate the signal.

5. The control valve according to claim 1, wherein, The location monitoring system includes: A tube containing the fluid, the tube being configured with a first end and a second end. A cylinder connected to the first end of the tube, the cylinder being configured to contain the fluid and to move simultaneously with the valve stem.

6. The control valve according to claim 1, wherein, The location monitoring system includes: A tube containing the fluid, the tube being configured with a first end and a second end. A cylinder, connected to the first end of the tube, the cylinder being configured with a reservoir to contain the fluid and configured to move simultaneously with the valve stem, and A piston having an end disposed within the cylinder and in contact with the fluid, the piston being configured to remain stationary relative to movement of the cylinder.

7. The control valve according to claim 1, wherein, The location monitoring system includes: A tube containing the fluid, the tube being configured with a first end and a second end. A cylinder, connected to the first end of the tube, the cylinder being configured with a reservoir to contain the fluid and configured to move simultaneously with the valve stem, and A piston having a first end fixed to the actuator and a second end disposed in the cylinder and in contact with the fluid, the piston being configured to remain stationary relative to movement of the cylinder.

8. The control valve according to claim 1, wherein, The location monitoring system includes a pressure sensor.

9. The control valve according to claim 1, wherein, The location monitoring system includes a pressure sensor that is sensitive to pressure changes on the order of mmWC / mbar.

10. The control valve according to claim 1, further comprising: A valve positioner having operating hardware configured to process the signal to calculate the position of the closing member.

11. A control valve, the control valve comprising: Actuator; A valve stem, which is connected to the actuator; The valve is connected to the valve stem; A tube having a first end connected to the valve stem and a fixed second end; Fluid, the fluid being disposed in the pipe; and A pressure sensor is coupled to the second end of the tube and is configured to generate a signal in response to the discharge pressure of the fluid in the tube.

12. The control valve according to claim 11, wherein, The movement of the valve stem changes the discharge pressure of the fluid in the pipe.

13. The control valve according to claim 11, wherein, The movement of the valve stem changes the distance between the first end and the second end of the tube.

14. The control valve according to claim 11, further comprising: A controller having operating hardware connected to the pressure sensor, the operating hardware being configured to process the signal to generate a value indicating the operating condition of the valve.

15. The control valve according to claim 11, further comprising: A cylinder is attached to the first end of the tube, the cylinder forming a reservoir and having an opening so that fluid can enter the reservoir from the tube.

16. The control valve according to claim 11, further comprising: A cylinder, connected to the first end of the tube, the cylinder forming a reservoir and having an opening to allow fluid to enter the reservoir from the tube. The cylinder is capable of moving simultaneously with the valve stem.

17. A control valve, the control valve comprising: Actuator; A valve stem, which is connected to the actuator, is configured to change from a first position to a second position; A fluid column having fluid disposed therein; and A pressure sensor, which is connected to the fluid column, The fluid column is arranged such that the discharge pressure of the fluid changes in response to the movement of the valve stem.

18. The control valve according to claim 17, wherein, The fluid column is arranged such that the discharge pressure of the fluid increases or decreases in response to the movement of the valve stem.

19. The control valve according to claim 17, wherein, The pressure sensor is configured to generate a signal corresponding to the discharge pressure of the fluid.

20. The control valve according to claim 17, wherein, The pressure sensor is configured to generate a signal corresponding to the discharge pressure of the fluid.

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