This disclosure relates generally to fluid control systems and, more particularly, to methods and apparatus to generate fluid vortices in stagnation areas in fluid control systems.
Typically, it is necessary to control process fluids in industrial processes, such as oil and gas pipeline distribution systems, chemical processing plants, and sanitary processes such as, for example, food and beverage processes, pharmaceutical processes, cosmetics production processes, etc. Generally, process conditions, such as pressure, temperature, and process fluid characteristics dictate the type of valves and valve components that may be used to implement a fluid control system. Valves typically have a fluid passageway, including an inlet and an outlet, which passes through the valve body. Other valve components, such as a bonnet, a valve stem or a flow control element may extend into the passageway. Often, the configuration of these components in the passageway results in fluid stagnation areas, which are particularly problematic in fluid control systems that require sanitary conditions. In the stagnation areas, the flow of fluid is reduced, air pockets may form and, as a result, microorganisms and other contaminants may accumulate within the valve and/or other areas along the path of fluid flow.
When the plug 112 is in the position shown in
In the food processing, cosmetic and bio-technical industries, it is common to employ valves, pipes and other fluid control components that promote sanitary conditions by, for example, preventing the accumulation of contaminants within the fluid control components. One such example is shown in
In the design of
In accordance with one example, a valve includes a valve body and a fluid passage therethrough. The fluid passage includes an inlet, an outlet and a stagnation area. The valve includes a control element within the fluid passage to control a flow of fluid through the passage and a vortex generating structure to direct a fluid within the fluid passage into the stagnation area.
In accordance with another example, a vortex generating apparatus includes a fluid communication element, a fluid stagnation area proximate to the fluid communication element, and a vortex generator coupled to the fluid communication element. The vortex generator is adapted to generate at least one vortex in the fluid stagnation area.
In accordance with yet another example, a fluid communication device includes a passage for communicating fluid through the fluid communication device, a stagnation area within the passage, and a diverting structure within the passage. The diverting structure is configured to divert fluid into the stagnation area.
In general, the example fluid control valves described herein include a valve body through which fluid may flow via a fluid passage having an inlet and an outlet. The fluid passage may have one or more stagnation areas in which fluids and/or contaminants may accumulate. To minimize and/or prevent the adverse effects of the stagnation area(s) (e.g., bacteria growth), the example fluid control valves described herein include a vortex generating structure configured to direct fluid into the stagnation area(s).
Some known fluid control valves incorporate fluid passage designs that are substantially void of stagnation areas. However, such fluid passage designs typically increase the complexity and manufacturing cost of a fluid valve. In contrast, the example fluid control valves described herein include a vortex generating structure that enables the use of relatively easy-to-manufacture (i.e., lower cost) valve designs while eliminating or minimizing the adverse effects of stagnation areas.
In one example, a fluid control valve includes a vortex generating structure integral with a valve bonnet and/or includes a vortex generating structure upstream and proximate to any stagnation area(s) within the valve. In another example, a fluid control valve employs a vortex generating structure in a section of pipe proximate to an inlet of the valve to impart adequate fluid turbulence to incoming fluid to facilitate the flushing of any stagnation area(s) within the valve.
A valve stem 316 extends through a center portion of the bonnet 310 and has one end that is configured to be operatively coupled to an actuator (not shown) and another end coupled to a plug 318 or other fluid control element adapted to allow and/or block fluid flow through the valve 300. The stem 316 is axially slidable within the bonnet 310 and sealed to the bonnet 310 via a stem seal 320. The bonnet 310 is further sealed to the valve body 302 via a bonnet seal 322. The seals 320 and 322 may be O-rings or other suitable sealing structures that surround the stem 316 and the bonnet 310, respectively, to prevent process fluid from leaking or seeping out of the valve 300.
The plug 318 is adapted to axially engage the valve seat 308 and control the flow of fluid through the valve 300 via the passageways 304 and 306. In the position shown in
In the open position or the closed position, process fluid including liquids and gases, may accumulate in a dead leg or stagnation area 324, which is an area of fluid stagnation around the bonnet 310 near an upper portion of the extension 312. However, the flange 314 alters the flow of the fluid in the passageways 304 and 306 as shown by example fluid flow arrows 350. In particular, fluid flowing through the inlet passageway 304 strikes the flange 314, which diverts or directs some of the fluid into the stagnation area 324 to create vortices or eddies therein. In other words, the flange 314 functions as a downstream flow impediment that creates a hydraulic jump, which dissipates energy as turbulence or vorticies. The turbulence or vortices clear out the stagnation area 324 by making them less stagnate, which breaks up or removes air pockets and cleans out microorganisms, fluids, and/or any other contaminants that have accumulated therein.
Generally, it is undesirable to create vortices, eddies, or other turbulence in process fluid systems because such turbulence is considered inefficient (i.e., vortices, eddies, turbulence, etc. tend to increase flow resistance). As is known, a straight-sided bonnet is relatively efficient and provides a relatively low flow coefficient or flow resistance. However, such straight-sided bonnets do not promote sanitary conditions for valves having a dead leg or stagnation area.
As described above in connection with the example valve 300, the flange 314 functions as a vorticity generator, which creates vorticies, eddies, or turbulence in the stagnation area 324 and drives out gasses (e.g., air) or other stagnant fluids and creates a fluid velocity that prevents the accumulation and attachment of organisms, such as, for example, bacteria or other contaminants. Thus, the flange 314 causes at least some of the fluid passing through the valve 300 via the passageways 304 and 306 to be diverted or directed in a manner that cleans the stagnation area 324.
The vortex generator 301 may be used to facilitate and/or improve clean-in-place (CIP), hot-water-in-place (HWIP), steam-in-place (SIP) and/or other well-known cleaning processes. For example, the vortex generator 301 may be used to direct cleaning chemicals, hot water, and/or steam into the stagnation area 324 as described above. When used with CIP systems, the vortex generator 301 increases efficiency of the cleaning process by requiring less rinse water after cleaning agents clean an inside surface of the valve 300. Alternatively or additionally, the cleaning process can be performed using only hot water or a caustic material followed by hot water instead of a caustic material followed by steam. In any case, the vortex generator 301 of
In the example valve of
Furthermore, the vortex generator 301 may be used on other components in a fluid control system. For example, the example vortex generator 301 may be used in connection with T-mounted sensors in the process stream such as, for example, a temperature probe. A temperature probe mounted on the top of a pipeline may create dead legs in the adjacent area of the process stream. Coupling the sensor with a vortex generator such as the example vortex generator 301 would reduce the stagnation in the dead legs and promote sanitary conditions in a manner similar to that described above.
In an alternative embodiment shown in
In the example of
Instead of, or in addition to the propeller 455, individual blades may be attached to the pipe 460 interior without the hub 456. Such individual blades, attached to the pipe 460 and separated by a longitudinal distance, impart a vortex in the fluid while minimizing fluid flow resistance. The number and placement of the individual blades permit a tradeoff between fluid flow resistance while causing fluid to spin with respect to the axis of the pipe 460, thereby directing fluid into the stagnation area 424. As with the flange 314 of the example shown in
In addition, the example propeller 455 may also be used in other areas of a fluid control system. For example, in a fluid control system such as, for example, a sanitary system, laminar boundary layers may form in a long straight run of a pipe. In that boundary layer the shear due to velocity is low enough that contaminants such as, for example, bacteria growth, may accumulate. Positioning a propeller 455, or other vortex generating structure, in the straight run would generate swirling turbulence throughout the stream, even along the pipe walls, which helps disintegrate the boundary layer and, thus, clear out the contaminants. Not only would this configuration enable effective cleaning at low velocities, the vortex generating structure may clean the pipes better than current line velocities.
In an alternative embodiment shown in
In yet another alternative embodiment, the spiral structure includes a spiral ridge instead of the spiral grooves 565 of
The example vortex generating structures could be used to reduce the need for cleaning processes to be performed in fluid communication systems due to a reduction and/or prevention of the stagnation of fluid in a dead leg or other stagnation area(s). Such a reduction and/or prevention of fluid stagnation promotes sanitary conditions and decreases the presence of contaminants in the process fluid. For example, increased turbulence in fluid stagnation areas reduces or eliminates conditions favorable to bacterial growth, thereby decreasing the frequency at which cleaning processes must be performed on a fluid distribution or control system. This decreased need for cleaning reduces cleaning costs including the costs associated with downtime of the fluid processing system.
Further, the example vortex generating structures enable cleaning processes (e.g., CIP, HWIP, SIP, etc.) to operate more efficiently by directing or diverting cleaning chemicals, steam, and/or hot water into stagnation areas. The increased efficiency of cleaning operations may decrease the amount of chemicals and/or energy needed to perform the cleaning processes.
Still further, the example vortex generating structures could be coupled to or formed within other structures or components of a valve, pipeline or other fluid or material communication element or device. For example, a temperature or other sensor in a valve or a pipe may be fitted with a ramp-shaped, curved or spiral structure, such as the example described above with respect to
Although certain example methods, apparatus and articles of manufacture have been described herein, the scope of coverage of this patent is not limited thereto. On the contrary, this patent covers all methods, apparatus and articles of manufacture fairly falling within the scope of the appended claims either literally or under the doctrine of equivalents.