This patent relates to fluid valves and, more specifically, to fluid valves having multiple fluid flow control members.
Process control systems use a variety of field devices to control process parameters. For example, a three-way fluid valve may be employed for use with converging applications (i.e., directing fluid flow from one of two inlets to a common outlet), or diverting applications (i.e., directing fluid flow from a common inlet to one of two outlets). A three-way valve typically includes a valve body defining a first fluid flow passageway between a first port and a second port of the fluid valve and a second fluid flow passageway between the first port and a third port of the fluid valve. To control the fluid flow through the respective first and second fluid flow passageways, a three-way valve typically employs a flow control member that moves relative to a first valve seat of the first passageway and a second valve seat of the second passageway.
However, in a three-way valve, the valve plug can only sealingly engage one of the valve seats at a time. In other words, the flow control member is not capable of simultaneously engaging the first and second valve seats to prevent or restrict fluid flow through both passageways at the same time. As a result, additional upstream and/or downstream fluid flow control devices are necessary to prevent fluid flow through all the ports of the fluid valve simultaneously.
An example valve trim apparatus includes a first valve trim apparatus to control fluid flow through a first passageway of a fluid valve and a second valve trim apparatus to control fluid flow through a second passageway of the fluid valve. The first passageway is different than the second passageway and the first valve trim apparatus includes a first valve stem to slidably receive a second valve stem of the second valve trim apparatus.
An example fluid valve includes a valve body defining a first passageway between a first port and a second port and a second passageway between the first port and a third port. A first flow control member is disposed in the first passageway to control fluid flow through the first passageway a second flow control member is disposed in the second passageway to control fluid flow through the second passageway. The second flow control member is slidably coupled to the first flow control member.
The examples described herein relate to fluid valves having multiple fluid flow control members (e.g., valve plugs) or valve trim apparatus. More specifically, the fluid flow control members described herein control fluid flow through multiple orifices and/or passageways of a fluid valve. In particular, the example fluid flow control members described herein may independently control fluid flow through the respective fluid flow passageways. In this manner, the example flow control members described herein may be simultaneously positioned to sealingly engage respective valve seats to prevent or restrict fluid flow through all of the respective fluid flow passageways of the fluid valve (e.g., a closed position of the fluid valve) simultaneously. As a result, additional shut-off valves or flow control devices are not required upstream and/or downstream from passageways of the fluid valve to prevent or restrict fluid flow through all the passageways simultaneously. In contrast, conventional three-way fluid valves, for example, can only prevent or restrict fluid flow through only one of the passageways at a time.
To move a first flow control member described herein independently of and relative to a second flow control member described herein, the examples described herein may include a first valve trim apparatus slidably coupled relative to a second valve trim apparatus. For example, a first valve trim apparatus described herein may have a first control member operatively coupled to a first actuator via a first valve stem and a second valve trim apparatus described herein may have a second flow control member operatively coupled to a second actuator via a second valve stem, where the first valve stem is slidably coupled to the second valve stem. In particular, the first valve stem may include an aperture to slidably receive the second valve stem such that the second valve stem slides relative to, through or within the first valve stem and the first valve stem slides relative to, about or over the second valve stem. In some examples, a first valve stem described herein may provide a sleeve-like structure to slidably receive a second valve stem having a rod-like structure.
Additionally, because each of the actuators may move the first valve stem independently from the second valve stem, the first flow control member may be positioned relative to a first valve seat to provide a first fluid flow opening or rate through a first passageway that varies independently from a second fluid flow opening or rate through a second passageway provided by the position of the second flow control member relative to the second valve seat.
In operation, an actuator (not shown) moves the valve plug 102 relative to the first valve seat 104 and the second valve seat 114. For example, at a zero-percent stroke-length position of the actuator, the valve plug 102 sealingly engages the first valve seat 104 to restrict fluid flow through the first passageway 106 and the valve plug 102 is in a fully open position relative to the second valve seat 114 to allow fluid flow through the second passageway 116. At a one-hundred percent stroke-length position of the actuator, the valve plug 102 is in a fully open position relative to the first valve seat 104 to allow fluid flow through the first passageway 106 and sealingly engages the second valve seat 114 to restrict fluid flow through the second passageway 116.
Thus, the valve plug 102 can only sealingly engage one of the valve seats 104, 114 to prevent or restrict fluid flow through only one of the fluid flow passageways 106 or 116 at the same time or a particular instance.
To prevent or restrict fluid flow through both of the fluid flow passageways 106 and 116 simultaneously, one or more shut-off valves or flow control devices 120, 122 and/or 124 are fluidly coupled upstream and/or downstream from the respective fluid ports 110, 112 and/or 118. In this manner, for example, when the valve plug 102 sealingly engages the first valve seat 104, the shut-off valve 120 upstream of the port 110 and/or the shut-off valve 124 downstream of the port 118 may be moved to a closed position to prevent fluid flow through the second passageway 116 when the valve plug 102 is in sealing engagement with the first valve seat 104. Such additional flow control devices 120, 122, 124 increase manufacturing costs and/or increase the complexity and design of a process system.
Additionally or alternatively, when the position of the valve plug 102 is moved to a 25-percent stroke-length position relative to the first valve seat 104, the valve plug 102 is also positioned at a 75-percent stroke-length position relative to the second valve seat 114, provided that a zero-percent stroke position of an actuator causes the valve plug 102 to move to a closed position relative to the first valve plug 104 and a fully open position relative to the second valve seat 114. Thus, a fluid flow opening or rate through the first passageway 106 varies inversely relative to a fluid flow opening or rate through the second passageway 116.
The known valve 100 of
The fluid valve 300 of
Unlike the fluid valve 100 of
In the illustrated example of
The first valve seat 328 is disposed within the first passageway 310 to define a first orifice 336 of the first passageway 310 and the second valve seat 334 is disposed within the second passageway 312 to define a second orifice 338 of the second passageway 312. In operation, the first flow control member 324 moves relative to the first valve seat 328 to control or modulate fluid flow through the first passageway 310 and the second flow control member 330 moves relative to the second valve seat 334 to control or modulate fluid flow through the second passageway 312. In particular, as described in greater detail below, the first flow control member 324 moves independently relative to the second flow control member 330.
The first valve trim apparatus 320 of the illustrated example also includes a first seal or packing system 340 to prevent fluid leakage to the environment via the first valve stem 326. Similarly, the second valve trim apparatus 322 of the illustrated example includes a second seal or packing system 342 to prevent fluid leakage to the environment via the second valve stem 332.
The first flow control member 324 is coupled to a first end 414a of the first valve stem 326. Additionally, the first valve stem 326 and the first flow control member 324 have respective apertures 416 and 418 to slidably receive the second valve stem 332. For example, each of the apertures 416 and 418 of the respective valve stem 332 and the first flow control member 324 has an opening or diameter that is sized to receive (e.g., is smaller than) an outer surface or diameter 420 of the second valve stem 332. In this manner, the second valve stem 332 slides relative to, within or through the first valve stem 326 and the first flow control member 324. As shown in
The first valve stem 326 also includes a cavity 422 adjacent a second end 414b of the first valve stem 326 to receive the second packing system 342. The second packing system 342 (e.g., a live-loaded packing) includes packing or seals 424 (e.g., graphite rings, PTFE rings, etc.) that are disposed within the cavity 422 of the first valve stem 326. A packing retainer or follower 426 retains the packing 424 within the cavity 422. In the illustrated example, the packing system 342 includes an inner opening or diameter that is sized to slidably engage the outer surface 420 of the second valve stem 332 and includes an outer surface or diameter that is sized to fit with an inner opening or diameter 430 of the cavity 422. The second packing system 342 seals the outer surface of the second valve stem 332 and an inner surface or diameter of the first valve stem 330 to prevent fluid leakage along the second valve stem 332 and to the environment via the bonnet 406 and the respective apertures 416 and 418 of the first valve stem 326 and the first flow control member 324.
Thus, the first valve stem 326 moves or slides relative to the opening 404 of the bonnet 406 and the packing system 340 and the second valve stem 332 moves or slides relative to the packing system 342 and the apertures 416 and 418 of the first valve stem 326 and the first flow control member 324.
In the example of
The example fluid valve 300 of
The first valve trim apparatus 620 includes a flow control member 624 (e.g., a valve plug) coupled to a first valve stem 626 (e.g., a sleeve) and the second valve trim apparatus 622 includes a second flow control member 628 (e.g., a valve plug) coupled to a second valve stem 630 (e.g., a rod). More specifically, the first valve stem 626 and the first flow control member 624 slidably receive the second valve stem 630. Although not shown, each of the valve trim apparatus 620 and 622 of
The first flow control member 624 moves relative to a first seal or valve seat 636 disposed within the first passageway 610 to control or modulate the fluid flow through the first passageway 610 and the second flow control member 628 moves relative to a second seal or valve seat 638 disposed within the second passageway 612 to control or modulate fluid flow through the second passageway 612.
In particular, the first flow control member 624 sealingly engages the valve seat 636 of the first passageway 610 to restrict or prevent fluid flow through the first passageway 610 and moves away from the valve seat 636 to allow fluid flow through the first passageway 610. Likewise, the second flow control member 628 sealingly engages the valve seat 638 of the second passageway 616 to restrict or prevent fluid flow through the second passageway 616 and moves away from the valve seat 638 to allow fluid flow through the second passageway 616.
In the illustrated example, the actuator 602 moves the first and second flow control members 624 and 628 relative to the respective valve seats 636 and 638 independently of each other. The actuator 602 shown in
The first piston 644 is disposed within a first actuator chamber 648 to define a first control chamber 648a and a second control chamber 648b.Similarly, the second piston 646 is disposed within a second actuator chamber 650 to define a third control chamber 650a and a fourth control chamber 650b. The actuator chambers 648 and 650 are integrally formed with a housing or casing of the actuator 602.
The actuator 602 also includes an actuator stem 652 to operatively couple the first valve stem 626 and the first piston 644. As shown, the actuator stem 652 may be integrally formed with the piston 644 and/or may be coupled to the piston 644 via a fastener, welding, etc., at a first end 652a. A second end 652b of the actuator stem 652 is coupled to the first valve stem 626 via a connector 654. Additionally, the actuator stem 652 and the piston 644 each include an aperture or opening (not shown) to slidably receive the second valve stem 630, which is coupled to the second piston 646 via a fastener 656. Thus, the first piston 644 moves the first flow control member 624 relative to the valve seat 636 via the first valve stem 626, the actuator stem 652 and the connector 654. Similarly, the second piston 646 moves the second flow control member 628 relative to the second valve seat 638 via the second valve stem 630 that slidably moves through the first piston 644, the actuator stem 652, the first valve stem 626 and the first flow control member 624.
The first piston 644 can operate independently from the second piston 646. As a result, the first piston 644 can operate or move the first flow control member 624 independently from the second flow control member 628. Likewise, the second piston 646 can operate or move the second flow control member 628 independently from the first flow control member 624. For example, as shown in
In operation, independent movement of the pistons 644 and 646 is controlled via a pressure differential provided across the respective pistons 644 and 646. More specifically, movement of the first piston 644 and, thus, the first flow control member 624, is controlled by conveying fluid (e.g., pressurized fluid) into and out of ports 662a and 662b, and movement of the second piston 646 and, thus, the second flow control member 628, is controlled by conveying fluid (e.g., pressurized fluid) into and out of ports 664a and 664b.
For example, a control fluid (e.g., pressurized air) is provided to, or exhausted from, the first and second chambers 648a and 648b via respective ports 662a and 662b to provide a pressure differential across the first piston 644 to move the first flow control member 624 relative to the first valve seat 636 and/or the second valve trim apparatus 622. Likewise, a control fluid (e.g., pressurized air) is provided to, or exhausted from, the third and fourth chambers 650a and 650b via respective ports 664a and 664b to provide a pressure differential across the second piston 646 to move the second flow control member 628 relative to the second valve seat 638 and/or the first valve trim apparatus 620. Additionally, although not shown, the example fluid valve assembly 600 may include duel control devices, positioners, and/or transmitters operatively coupled to each of the flow control devices 624 and 628 to detect or provide an indication of their respective positions (e.g., stroke-length positions).
For example, the first flow control member 624 may be positioned to a 10-percent troke-length position of the first piston 644 and the second fluid flow control member 628 may be positioned to a 30-percent stroke-length position of the second piston 646. In other examples, the positions of the flow control members 624 and 628 may be complementary or may coincide such that the first stroke-length position is 10-percent of the stroke-length of the first piston 644 and the second stroke-length position is 90-percent of the stroke-length of the second piston 646. Additionally or alternatively, the flow control members 624 and 628 may be at any positions relative to each other and/or their respective valve seats 636 and 638.
Thus, unlike the example fluid valves 100 and 200 of
Additionally or alternatively, unlike the fluid flow valves 100 and 200 of
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.
This patent claims the benefit of U.S. Provisional Patent Application Serial No. 61/522,334, filed on Aug. 11, 2011, entitled “FLUID VALVES HAVING MULTIPLE FLUID FLOW CONTROL MEMBERS,” which is hereby incorporated herein by reference in its entirety.
Number | Date | Country | |
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61522334 | Aug 2011 | US |