Monitoring the condition of the valve plug inside the valve

Abstract

Monitoring units are configured for use on valves. These configurations may include sensors that can generate data consistent with the physical condition of a closure member, such as a valve "plug," when the valve is in use on a process line. Analysis of this data may indicate erosion on the plug, which is often caused by a highly aggressive working fluid or other process (or application) conditions. A signal or warning from a process control system, or DCS, may alert an operator to perform timely maintenance to avoid problems that may arise as a result of the physical change in the valve plug.

Description

[Technical Field]

[0001] Flow control devices play a major role in many industrial facilities. For example, power plants and industrial processing facilities use different types of flow control devices to manage the flow of materials, typically fluids, throughout vast networks of pipes, tanks, generators, and other equipment. Control valves are useful for precisely regulating flow rates to meet process parameters. In the oil and gas industry, operators may effectively use control valves to control the flow of debris-laden fluids in hydrocracking or related processes. Fluids in these processes are known to be highly corrosive. Materials can rapidly degrade valve components directly in the flow path. Operators are keen to understand the wear patterns or characteristics of these components to properly maintain the devices and avoid costly repairs or untimely line shutdowns. Summary of the Invention

[0002] The subject matter of this disclosure relates to improvements that provide operators with data regarding the status of devices on their process lines. Of particular interest are embodiments using sensors that can monitor wear on specific components on valves or flow control devices. These embodiments can provide real-time data to capture the effects of highly aggressive process fluids. As a result, operators can preemptively arrange for maintenance to occur at timely service points, for example, before components corrode to the point that they affect valve performance. This feature can save significant costs because maintenance is performed on devices that are approaching, but have not yet experienced, a catastrophic failure that could affect output, product quality, or even irreparably damage the process line. [Brief explanation of the drawings]

[0003] This specification makes reference to the following drawings: [Figure 1]1 shows a schematic diagram of an embodiment of a monitoring unit. [Figure 2] 2 shows a schematic diagram of an example of a sensor unit for the monitoring unit of FIG. 1; [Figure 3] 2 shows a schematic diagram of an example of a sensor unit for the monitoring unit of FIG. 1; [Figure 4] 2 shows a schematic diagram of an example of a sensor unit for the monitoring unit of FIG. 1; [Figure 5] FIG. 4 shows a schematic diagram of an example of a sensor for use in the sensor unit of FIGS. 2 and 3. [Figure 6] 2 shows an elevation view of a section of a structure for the monitoring unit of FIG. 1; [Figure 7] FIG. 1 is an elevational view of a cross section of a structure for a flow control device.

[0004] These drawings and any descriptions herein represent examples that may disclose or describe the invention. These examples, including the best mode, enable one skilled in the art to practice the invention, including making and using any device or system and performing any incorporated methods. The drawings are not to scale unless otherwise noted in the discussion. Elements in the examples may appear in more than one of the figures or in combinations of the figures. The figures may use like reference numerals to indicate identical or corresponding elements. Methods are merely illustrative and may be modified, for example, by reordering, adding, removing, and / or changing individual steps or stages. Although such stages, as well as any parts, components, elements, or functions, may be identified in the singular using the word "a" or "an," this should not, however, exclude a plural form of such designation unless the specification expressly states or explains such exclusion. Similarly, any reference to "one embodiment" or "an implementation" should not exclude the existence of additional embodiments or implementations that also incorporate the recited features. DETAILED DESCRIPTION OF THE INVENTION

[0005] Consider now the features of the examples shown in the figures above. These examples may embody valves, such as control valves, configured to monitor wear of specific components or parts, typically in critical areas of a device. These components may reside in locations not generally accessible for easy visual inspection. For example, the proposed design can provide quantitative data regarding the condition of components in direct contact with the flow of working fluid. This design may provide insight not previously available through non-invasive diagnostics that a technician may perform with a handheld ultrasound device. Other embodiments are within the scope of this disclosure.

[0006] 1 shows an example of a monitoring unit 100, typically found in a distribution network 102 designed to transport a material 104 throughout a network of conduits 106. The network 102 may include a flow control device 108 having a valve positioner 110. It may also include a valve body 112 for connecting the device in-line with the conduits 106. The valve body 112 may support an actuator 114. A valve stem 116 may couple the actuator 114 to a valve mechanism, shown here to include a seat 118 and a closure member 120. In one implementation, the monitoring unit 100 may include a sensor unit 122 in proximity to the closure member 120.

[0007] Generally, the monitoring unit 100 can be configured to generate data. These configurations can operate continuously to detect prevailing conditions during service. This data can correspond, for example, to wear, erosion, or other surface defects that may result from exposure to harsh or corrosive environments common in oil and gas applications. The data can provide the operator with real-time information about the physical condition of their device. As a result, the operator can make decisions regarding trends that indicate potential problems or issues, often before the component in question fails or begins to adversely affect the valve's performance.

[0008] Distribution systems 102 may be configured to deliver or move resources. These configurations may embody vast infrastructures. Materials 104 may include gases, liquids, solids, or even mixtures. Conduits 106 often include pipes or pipelines that connect to pumps, compressors, vessels, boilers, etc. Pipes may also connect to tanks or reservoirs. In many facilities, this equipment forms a complex network.

[0009] The flow controllers 108 may be configured to regulate the flow of material 104 through the conduits 106. These components may embody control valves and similar devices. The valve positioners 110 may be configured to process and generate signals. These components may be connected to a control network (or “distributed control system” or “DCS”), which maintains the operation of all devices on the process line to ensure that material flows according to the process. The DCS may generate control signals having operating parameters that describe or define the operation of the flow controllers 108 for this purpose. The valve positioners 110 may include electrical and computing components (e.g., processors, memory, executable instructions, etc.). These components may also include electro-pneumatic devices that operate based on an incoming pneumatic supply signal to deliver a control signal, typically compressed air, at a pressure that ensures that the flow controller 108 delivers material 104 downstream according to the process parameters.

[0010] Components of the flow control device 108 may be configured to regulate the flow of material 104 through the conduit 106. The valve body 112 may often be a cast or machined metal structure. This structure may form flanges at the openings I and O. Adjacent pipes 106 may be connected to these flanges. The actuator 114 may embody a pneumatic device. A compressed air signal may actuate this device to generate a load. The valve stem 116 may embody an elongated cylinder or rod that directs this load to the valve mechanisms 118 and 120. This feature helps position the closure member 120, often a "plug" made of metal or metal alloy, at a desired position relative to the seat 118. This desired position, or "set point," may correspond to a flow parameter of the material 104 to meet process requirements or parameters. The plug 120 may move relative to the seat 118 to meet or achieve the set point. Movement is generally along the axis of seat 118, but may be "up" or "down" for valves oriented vertically on a process line. As noted above, the position of plug 120 may directly correspond to the flow rate of natural gas (or other resource) flowing through (or from upstream to downstream of) seat 118.

[0011] The sensor unit 122 can be configured to measure conditions on the flow control device 108. These configurations can include devices that are sensitive to changes in physical conditions or structures on components, including the plug 120, that are in contact with the material 104. The devices can be internal to the flow control device 108. In one implementation, the devices are integrated into structures in the valve body 112, such as structures that guide the plug 120. This feature provides data at locations close to the surfaces on the plug 120 that are exposed to the material 104. As a result, the data can clearly reflect the physical condition of (or on) the plug 120, which can be a precursor to a more widespread failure or problem on the flow control device 108. For example, erosion of the plug 120 can result in a change in flow rate that is outside of process parameters, even though the plug 120 may be in its desired position.

[0012] 2, 3, and 4 show schematic diagrams of the sensor unit 122. This configuration can form a sensing array 124 that occupies a portion of the valve body 112. The sensing array 124 can include sensing locations 126 that can generate data related to the plug 120, for example. As best shown in FIG. 3, the sensing array 124 configuration can also include two or more sensing locations 126. Data from these configurations can describe features or characteristics of the plug 120, such as surface condition or material composition. Processing of the data can then identify device problems or potential problems. These processes can allow operators to schedule maintenance to avoid changes in flow through the control valve 108 that could lead to catastrophic failure that could interrupt production or, worse, shut down the process line completely. This feature can provide data across more points of interest on the closure member 120. FIG. 4 shows an example with sensing locations 126 located on the plug 120 (or seat 118).

[0013] FIG. 5 shows a cross-sectional elevation view of an exemplary structure of the sensing location 126. This structure may include a sensor 128 with a property-sensitive device 130, such as a Hall-effect sensor or a linear variable differential transformer ("LVDT") sensor. This disclosure contemplates other types of technology as well. Non-contact sensors may be useful because they do not interfere with movement of a component such as the plug 120. These sensors may include magnetic flux leakage ("MFL") sensors or electromagnetic acoustic transducer ("EMAT") sensors. Wireless devices may be prevalent, for example, when the sensor 128 is attached to the plug 120 (as shown in FIG. 4 above), to accommodate relative movement of the component. In one implementation, the property-sensitive device 130 may reside within a carrier block 132, preferably made of metal or a similar material. The carrier block 132 may have a closed end 134 that "covers" the device 130. Preferably, the material properties (such as thickness or composition) do not interfere with the property-sensing device 130. The closed end 134 may result from a material layer 136 disposed on the carrier block 132. Additive manufacturing techniques may prove useful for this purpose. For example, ultrasonic additive manufacturing (or ultrasonic additive manufacturing, "UAM") may deposit a thin metal foil onto the carrier block 132 that does not interfere with or disrupt the operation of the Hall Effect sensor (or generally, the property-sensing device 130).

[0014] FIG. 6 shows a cross-sectional elevation view of the flow control device 108. The valve body 112 can have a bore 138 for receiving the plug 120. The carrier block 132 can be inserted into an aperture 140, shown here as a through-hole, that penetrates the valve body 112 to the bore 138 and forms an opening 142. A lead wire L from the property-sensing device 130 can extend from the opening 142 in the outer surface 144 to connect with the valve positioner 110. A material layer 136 can be present in the opening 142 in the inner surface 146. This configuration positions the property-sensing device 130 in close proximity to the plug 120. A thin metal foil protects the property-sensing device 130 from the flow of the material 104. In one implementation, a coating 148 disposed on the plug 120 can stimulate the property-sensing device 130 to generate a signal. In the case of a Hall Effect sensor, the coating 148 can have a metal-containing composition. During use, the coating 148 may corrode or wear away, exposing the material underlying the plug 120. This underlying material does not stimulate the property-sensing device 130, thus altering or possibly eliminating the signal from the Hall Effect sensor. A process in the valve positioner 110 or DCS may generate an output in response to any change in the signal (or lack thereof). This output can alert an operator to a condition in the plug 120 that requires attention or maintenance.

[0015] FIG. 7 shows a cross-sectional elevation view of the flow control device 108. The structure includes an upper member 150 secured to a lower member or “flange” 152. Fasteners F, such as nuts and bolts, may serve this purpose. As shown, the seat 118 may include a seat ring 154. A venturi housing 156 may reside within the flange 152 below the seat ring 154. In one implementation, the valve stem 116 may extend through a packing 158 in the upper member 150, positioning the plug 120 in close proximity to the seat ring 154. The structure of the packing 158 allows movement of the valve stem 116 but is useful for preventing the flow control device 108 from expelling fugitive emissions. It may also be useful for the upper member 150 to include a sensing location 126. This feature may provide data reflecting the state of the valve stem 116. In one implementation, a sensor 122 at this location may generate a signal that may reflect the position of the plug 120. Processing of these signals may provide feedback to the DCS that the flow controller 108 has achieved its specified setpoint.

[0016] In view of the foregoing, improvements herein address operator concerns regarding life expectancy predictions for specific components on their process lines. Embodiments can monitor the physical condition of these components in real time with a level of accuracy unavailable with non-invasive techniques such as ultrasound. The resulting data and diagnostic analysis provide operators with insight into wear characteristics. This insight enables operators to act quickly or in a timely manner to avoid catastrophic failures that could reduce production quality or cause an unfortunate (and costly) shutdown of the process line.

[0017] The following examples include particular elements or clauses to describe embodiments contemplated within the scope of this specification. These elements may be combined with other elements and clauses to similarly describe embodiments. This specification may include and contemplate other examples that will occur to those skilled in the art. These other examples would fall within the scope of the claims, for example, if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements that differ insignificantly from the literal language of the claims.

Claims

1. A valve, A valve plug; a valve body having a passage for receiving the valve plug; a sensor unit attached to the valve body and generating a signal in response to a physical change in the surface of the valve plug.

2. 10. The valve of claim 1, wherein the sensor unit has a sensing location that generates a field into the flow path that interacts with the surface to generate the signal.

3. 10. The valve of claim 1, wherein the sensor unit has two or more sensing locations that generate a field into the flow path that interacts with the surface to generate the signal.

4. 2. The valve of claim 1, wherein the sensor unit comprises a characteristic sensitive device that generates the signal and resides at a closed end of a carrier block adjacent the flow path.

5. 2. The valve of claim 1, wherein the sensor unit comprises a characteristic sensitive device that generates the signal in response to a change in a field passing through a closed end of a carrier block adjacent the flow path.

6. 2. The valve of claim 1, wherein the sensor unit comprises a characteristic sensitive device that generates the signal in response to a change in a field that penetrates a thin metal foil on a carrier block adjacent the flow path.

7. 2. The valve of claim 1, wherein the sensor unit comprises a Hall Effect sensor at a position that interacts with the surface to generate the signal.

8. further comprising an aperture in the valve body; 2. The valve of claim 1, wherein the sensor unit comprises a property-sensitive device that generates the signal and resides within the aperture.

9. an aperture in the valve body having an opening in the flow passage; 2. The valve of claim 1, wherein the sensor unit comprises a characteristic sensitive device that generates the signal and resides in a carrier block having a closed end at the opening.

10. The valve of claim 1 , wherein the valve plug comprises a metallic coating disposed on the surface.

11. A valve, A valve plug; a valve body having a passage for receiving the valve plug; a characteristic-sensing device that generates a field that interacts with a surface of the valve plug to generate a signal.

12. The valve of claim 11 , wherein the property-sensitive device comprises a Hall effect sensor.

13. The valve of claim 11 , wherein the field comprises a magnetic field.

14. 12. The valve of claim 11, further comprising a material interposed between the property-sensitive device and the valve plug that does not interfere with the field.

15. 12. The valve of claim 11, further comprising a metal foil interposed between the property-sensitive device and the valve plug, the metal foil not interfering with the field.

16. The valve of claim 11 , wherein the valve plug comprises a metallic coating on the surface.

17. A valve, a valve plug having a coating on a surface thereof; a monitoring unit having one or more sensors configured to indicate a change in thickness of the coating.

18. 18. The valve of claim 17, wherein the sensor generates a signal in response to the coating.

19. 18. The valve of claim 17, wherein the sensor generates a signal that varies depending on the presence or absence of the coating.

20. 18. The valve of claim 17, wherein the coating comprises a metal.

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