Construction of valve bellows for valves

Abstract

Bellows are configured for use on valves. These configurations can include corrugations that are hollow to receive a valve stem therethrough. The corrugations can terminate at both ends with adapters. In one implementation, additive manufacturing can construct the bellows as a single or integral unit, avoiding welds or fasteners that can complicate the manufacture of the part. This technique can create an interface between the corrugations and the adapter that includes the same material as the adjacent part.

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. These devices may include components that prevent leakage of working fluid to the atmosphere. These components often allow for relative movement, which can complicate their ability to seal with other components to close any flow paths that could allow working fluid to leak out of the device. Summary of the Invention

[0002] The subject matter of this disclosure relates to improvements in the construction of these precautions. Of particular interest are embodiments that integrate parts to simplify assembly and improve functionality for reducing or preventing emissions. These embodiments can create a sealed enclosure that can contain accidental or "fugitive" emissions. This feature improves safety by largely preventing the escape of gases or vapors that are potentially dangerous to workers in the vicinity of control valves and similar flow control devices. An added benefit is reduced product loss, allowing operators to maintain productivity and increase revenue. [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 bellows. [Figure 2] 2 shows an elevational view of a section of the bellows embodiment of FIG. 1; [Figure 3] 2 shows an elevational view of the bellows embodiment of FIG. 1. [Figure 4] 2 shows an elevational view of a section of the bellows embodiment of FIG. 1; [Figure 5] 2 shows an elevational view of a section of the bellows embodiment of FIG. 1; [Figure 6] 1 shows an elevational view of a cross section of an embodiment of 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 designate identical or corresponding elements. Methods are merely illustrative, and individual steps or stages may be altered, for example, by reordering, adding, removing, and / or modifying. 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 does not exclude a plural form of such designation unless the specification expressly states or describes such exclusion. Similarly, any reference to "one embodiment" or "an implementation" does not exclude the existence of additional embodiments or implementations that also incorporate the recited features. DETAILED DESCRIPTION OF THE INVENTION

[0005] The discussion will now describe the features of each of the examples shown in the figures above. These examples address the issue of bellows seals. These seals can seal around moving parts within the valve, thus preventing fugitive emissions. As described herein, the proposed designs are assembled into the valve without the need for post-processing welds (or similar mechanical fasteners). Other embodiments are within the scope of this disclosure.

[0006] 1 shows an example of a valve bellows 100, which is typically found in a distribution network 102 designed to transport a material 104 throughout a network of conduits 106. The network 102 includes a flow control device 108 with a valve positioner 110 and a valve body 112, which may be connected in series with the conduits 106. The valve body 112 may house a valve mechanism, shown here to include a seat 114 and a closure member 116. An actuator 118 may be coupled to the closure member 116 via a valve stem 120. In one implementation, the valve bellows 100 may include a bellows 122 that surrounds the valve stem 120.

[0007] Generally, the valve bellows 100 can be configured to prevent leakage. These configurations can include devices that can deflect and expand in response to loads. The devices can employ structures compatible with high temperatures or pressures, conditions often prevalent in oil and gas applications. As described herein, the proposed designs do not require welding or external separate fasteners to prevent the flow of fugitive emissions.

[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. These materials may flow through the system 102 at various pressures and temperatures. Conduits 106 may include pipes or pipelines that are often connected to pumps, compressors, vessels, boilers, etc. Pipes may also be connected to tanks or reservoirs. In many facilities, this equipment forms a complex network.

[0009] The flow controller 108 may be configured to regulate the flow rate of the material 104 through the conduit 106. These components may embody control valves and similar devices. The valve positioner 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 the material flows according to the process. The DCS may generate control signals having operating parameters that describe or define the operation of the flow controller 108 for this purpose. The valve positioner 110 may have operating hardware such as electrical components 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 the material 104 downstream according to the process parameters.

[0010] Components of the flow control device 108 can be configured to regulate the flow rate of the material 104 through the conduit 106. The valve body 112 often employs a structure made of cast or machined metal. This structure can form flanges at the openings I and O. Adjacent pipes 106 can be connected to these flanges. The valve mechanisms 114 and 116 help regulate the flow rate. The actuator 118 can embody a pneumatic device. A compressed air signal from the valve positioner 110 can actuate this device to generate a load. The valve stem 120 can embody an elongated cylinder or rod that directs this load toward the valve mechanisms 114 and 116. This feature helps position the closure member 116, often a "plug" made of metal or metal alloy, at a desired position relative to the seat 114. This desired position, or "set point," can correspond to a flow parameter of the material 104 to meet process requirements or parameters. The plug 116 can move relative to the seat 114 to meet or achieve the set point. Movement is generally along the axis of seat 114, or "up" or "down" for a valve 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 bellows 122 can be configured to prevent the material 104 from exiting the flow control device 108. These configurations can include devices capable of transmitting axial motion. These devices can expand or contract, for example, in response to movement of the valve stem 120 (or plug 116). In one implementation, the device can form a hollow, continuous, convoluted tube. The structure can include a flexible or malleable material. The "convolutions" or "corrugations" of the surface can help absorb any deflection in response to movement of the plug 120. These features can minimize stress within the device, thereby extending its useful life. As described herein, this structure can integrate other components useful for attaching or securing the bellows 122 to the flow control device 108, instead of welding or fasteners. This feature avoids internal connections that can fail over time. Welding can also complicate assembly, which can increase lead time or labor and material costs.

[0012] 2, 3, and 4 illustrate an exemplary structure of the bellows 122. This structure includes a foldable portion 124 that surrounds the valve stem 118. The foldable portion 124 may comprise a thin wall 126, preferably made of metal or a similar material. The thin wall 126 may have a geometry that allows the structure to deflect or expand under load, preferably axially along the longitudinal axis C. This geometry may form a wave shape, or alternating regions of ridges and grooves. Additive manufacturing techniques (such as "3D printing") may also be used to expand the range of shapes available for this geometry. For example, it may prove useful to provide the thin wall 126 with angles, curves, shapes, bends, or similar geometries that can reduce stresses or other inherent conditions that could cause failure during use. Combinations of shapes may be widespread as well. As best shown in FIG. 3, the geometric shape may employ an angled shape S, although other shapes such as squares, rectangles, or diamonds may be widely common as well. FIG. 4 illustrates a structure having a pair of thin walls 126 that overlap each other to form an embedded wall or "layered" structure. Each of the walls 126 may form a cylinder about a longitudinal axis C. As shown, a first or "outer" cylinder may surround a second or "inner" cylinder. This feature effectively embeds the two pieces together, with at least a portion of the individual pieces overlapping each other.

[0013] FIG. 5 also shows a cross-sectional elevation view of an exemplary structure of the bellows 122. The thin wall 126 may connect with the adapter 128 at both ends. An interface 130 may bond these two components together. The interface 130 may be “seamless” or may be composed essentially of the same material as the adjacent components 126, 128. A homogenous material structure may form the components 126, 128 as a single or “integral” unit. This feature is useful because it avoids welding or external, separate fasteners. Additive manufacturing techniques (such as “3D printing”) may also prove useful for this construction scheme. The “lower” adapter 134 may have a tapered portion 136. At the other end, the “upper” adapter 138 may include a shoulder 140 with a groove 142 disposed therein. A counterbore 144 may extend through one side of the adapter 138 to receive a bushing 146.

[0014] FIG. 6 shows a cross-sectional elevation view of an exemplary structure of the flow control device 108. The units 126, 128 may reside inside an extension 148 that couples the bonnet 150 to the valve body 112. Fasteners (F), such as nuts or bolts, may be commonly used for this purpose. As shown, the parts 148, 150 may clamp the shoulder 140. A gasket 152 is inserted into the groove 138 and may also reside below the shoulder 140. This arrangement seals the gap G between the thin wall 126 and the interior of the extension 148. In one implementation, a packing 154 may reside within the bonnet 150. The structure of the packing 154 allows movement of the valve stem 120 while helping to prevent the flow control device 108 from expelling fugitive emissions.

[0015] In view of the above, improvements herein simplify the construction of control valves. Embodiments use a one-piece, single piece that eliminates the need for welding (or fasteners) to create a bellows seal. This feature can reduce manufacturing costs by avoiding the need for certain secondary operations (such as welding) or labor. As an added benefit, manufacturers can realize shorter lead times due to fewer manufacturing steps or processes.

[0016] 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 occur to those skilled in the art. These other examples 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 do not differ substantially from the literal language of the claims.

Claims

1. A valve, A valve stem; a bellows surrounding the valve stem, the bellows including flexible portions terminating at both ends in adapters, the flexible portions and the adapters being integrally formed to have a homogenous material structure throughout the bellows.

2. a bushing disposed in one of the adapters; The valve of claim 1 further comprising:

3. an extension forming a hollow tube surrounding said bellows; The valve of claim 1 further comprising:

4. an extension forming a hollow tube surrounding the bellows; a bonnet disposed at one end of the extension and clamping one of the adapters therebetween; The valve of claim 1 further comprising:

5. The valve of claim 1 , wherein one end of the flexible portion and one of the adapters form a seamless interface.

6. The valve of claim 1 , wherein the ends of the flexible portion and the adapter form a seamless interface.

7. The valve of claim 1 , wherein the flexible portion and the adapter have the same material composition.

8. The valve of claim 1 , wherein the flexible portion and the adapter have a homogenous composition therebetween.

9. The valve of claim 1 , wherein the flexible portion and the adapter are connected to one another without welding.

10. 10. The valve of claim 1, wherein the flexible portion and the adapter connect to one another without welding or external separate fasteners.

11. A valve, A valve stem; a bellows surrounding the valve stem, the bellows being integrally formed at opposite ends with a pair of adapters that couple to the valve stem.

12. 12. The valve of claim 11, wherein the bellows has corrugated thin walls.

13. 12. The valve of claim 11, wherein the bellows has a thin wall with a groove that allows the thin wall to deflect along its longitudinal axis.

14. 12. The valve of claim 11, wherein the bellows has a thin wall with an angled shape, the angled shape allowing the thin wall to deflect along its longitudinal axis.

15. 12. The valve of claim 11, wherein the bellows has a thin wall having the same material composition as the adapter.

16. 12. The valve of claim 11, wherein the bellows has a pair of overlapping thin walls.

17. 12. The valve of claim 11, wherein the bellows has a first wall forming a first cylinder and a second wall forming a second cylinder inside the first cylinder.

18. 12. The valve of claim 11, wherein the bellows has a first wall forming a first cylinder and a second wall forming a second cylinder inside and integral with the first cylinder.

19. 12. The valve of claim 11, wherein the bellows and the adapter are connected to one another without welding.

20. 12. The valve of claim 11, wherein the bellows and the adapter connect to one another without welding or external separate fasteners.

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