Patent Application
20110174398
This patent relates generally to fluid regulators and, more particularly, to valve apparatus to prevent contamination of a fluid in a fluid regulator.
Fluid regulators are commonly distributed throughout process control systems to control the pressures of various fluids (e.g., liquids, gasses, etc.). Fluid regulators are typically used to regulate the pressure of a fluid to a substantially constant value. Specifically, a fluid regulator has an inlet that typically receives a supply fluid at a relatively high pressure and provides a relatively lower and substantially constant pressure at an outlet.
To regulate the downstream pressure, fluids regulators commonly include a sensing element or diaphragm to sense an outlet pressure in fluid communication with a downstream source. A valve apparatus is disposed within the fluid flow passageway to control or modulate fluid flow between an inlet and the outlet. The valve apparatus is operatively coupled to the sensing element, which causes the valve apparatus to move between an open position to allow fluid flow between the inlet and the outlet and a closed position to prevent or restrict fluid flow between the inlet and the outlet based on a pressure differential across the sensing element.
To couple the valve apparatus in the fluid flow passageway, some known fluid regulators employ a retainer or other member that is threadably coupled to a bore of the fluid regulator body. However, during assembly, such a threaded connection may form impurities (e.g., particulate, debris or contaminate) downstream from a filter of the valve apparatus. In operation, a high pressure process fluid may cause impurities to flow in the fluid flow passageway and contaminate downstream components or equipment. For high-purity applications, a contaminated fluid may be unacceptable. Additionally or alternatively, impurities may settle on a sealing surface of the valve apparatus, which may cause an improper seal when the fluid regulator is in a closed position and/or cause damage to the valve apparatus.
In one example, a valve apparatus includes a housing disposed within a fluid flow passageway of the fluid regulator to define a low-pressure side of the fluid flow passageway and a high-pressure side of the fluid flow passageway. The housing has a bore that at least partially defines the fluid flow passageway when coupled to the fluid regulator. The housing has a movable valve assembly disposed within the bore via a non-threaded connection in fluid communication with the low-pressure side of the fluid flow passageway and external threads to threadably couple the housing to an opening of the fluid regulator. A seal system prevents impurities from flowing between the high-pressure side of the fluid flow passageway and the low-pressure side of the fluid flow passageway.
In another example, a fluid regulator includes a valve body having a threaded opening that at least partially defines a fluid flow passageway between an inlet and an outlet. The fluid regulator includes a valve cartridge having a housing that includes external threads to removably couple the valve cartridge to the threaded opening of the valve body and the valve cartridge has a filter coupled to the housing. The housing has a bore to receive a flow control assembly such that the flow control assembly is coupled to the housing via a non-threaded connection downstream from the filter. A seal is coupled to the housing of the valve cartridge and the seal is positioned between the external threads of the valve cartridge and a sensing chamber of the fluid regulator to prevent impurities from contaminating a process fluid downstream of the filter where the seal and the filter isolate impurities within the opening of the fluid regulator upstream from the filter.
Example valve apparatus described herein significantly reduce or prevent impurities (e.g., contaminate, debris, particulate, etc.) from flowing to downstream components or equipment and/or from accumulating on sealing surfaces of the valve apparatus. More specifically, the example valve apparatus described herein may have external threads to removably couple the valve apparatus to a fluid regulator body. When coupled to the fluid regulator body, the valve apparatus defines a low-pressure side of a fluid flow passageway and a high-pressure side of the fluid flow passageway and may include a movable valve member to control the fluid flow between the low-pressure side and the high-pressure side of the passageway. Unlike conventional or known valve apparatus, the valve apparatus described herein employ a seal system to prevent impurities from flowing between the high-pressure side of the fluid flow passageway and the low-pressure side of the fluid flow passageway. In other words, the seal system may prevent impurities from flowing in a filtered portion of the fluid flow passageway of the fluid regulator. In some examples, a seal system may include a seal disposed on a low pressure side of the external threads of the valve apparatus. For example, a seal may be disposed between external threads of the valve apparatus and a sensing chamber of the fluid regulator to prevent impurities from flowing in a fluid flow passageway via the sensing chamber. Thus, the example seal prevents fluid communication between the external threads of the valve assembly and the fluid flow passageway.
Additionally, in some examples, the seal system of the valve apparatus may include a filter disposed in the fluid flow passageway such that the external threads are disposed between the filter and the seal. In this manner, the example seal and filter prevent impurities from flowing in the fluid flow passageway. In particular, the example filter and the seal isolate or trap impurities (e.g., impurities produced by the external threads) upstream from the filter and prevent such impurities from flowing in the fluid flow passageway and/or accumulating on a valve seat or fluid control apparatus. Thus, the example filter and the seal trap or contain any impurities upstream of the filter.
Further, unlike conventional fluid regulators, the valve apparatus of the illustrated example retains a movable flow control assembly within a bore of the valve apparatus via a non-threaded connection. In other words, the example valve apparatus described herein do not have threaded connections downstream from the filter or a filtered-side of the fluid flow passageway. Thus, the non-threaded connection further reduces the likelihood of contamination of the process fluid downstream from the filter.
In yet other examples, an example seal system of a valve apparatus may have a first seal (e.g., an O-ring) disposed adjacent a first side of the external threads of the valve apparatus (i.e., the low-pressure side of the passageway) and a second seal (e.g., an O-ring) disposed adjacent a second side of the external threads (i.e., the high-pressure side of the passageway). In this manner, the example first and second seals capture impurities between the external threads that may be produced during assembly of the fluid regulator.
Before discussing an example fluid regulator described herein, a brief description of a known fluid regulator 100 is provided in
A valve apparatus or poppet 118 moves relative to a valve seat 120 to regulate or modulate fluid flow between the inlet 106 and the outlet 108. A biasing element 122 biases the poppet 118 toward the valve seat 120. The poppet 118 also includes a stem 124 to operatively couple the diaphragm 112 and the poppet 118. A retainer 126 retains the valve seat 120 and the poppet 118 within a bore 130 of the valve body 102.
During assembly, the biasing element 122 and the poppet 118 are disposed within the bore 130. The valve seat 120 is disposed within the bore 130 and supported on a shoulder 132 of the bore 130. The retainer 126 is threadably coupled to the bore 130 of the valve body 102. The retainer 126 has a cylindrical body that includes external threads 134 to engage threads 136 of the valve body 102. However, during assembly, the threads 134 of the retainer 126 and/or the threads 136 of the valve body 102, whether plated or un-plated with a coating material, may cause or produce impurities (e.g., contaminate, particulate or debris). For example, during assembly, crowns of the threads 134, 136 may have burrs (e.g., that may be formed during machining of the threads 134, 136) that break-off or produce metal particles or shavings as the threads 134, 136 engage or rotate relative to each other. In some instances, in high pressure applications or pressure cycling applications that produce pressure pulses, a process fluid may cause the impurities or particulate to agitate and flow in the sensing chamber 114, thereby contaminating the process fluid flowing through the fluid flow passageway 116 and contaminating downstream components or equipment.
Additionally or alternatively, the impurities or particulate may flow or accumulate on the valve seat 120 and/or the poppet 118, thereby preventing a tight seal as the poppet 118 engages the valve seat 120 when the fluid regulator 100 is in a closed position. Additionally, accumulation of impurities on the valve seat 120 and/or the poppet 118 may cause damage to the poppet 118 and/or the valve seat 120, thereby reducing the operational life of the poppet 118 and/or the valve seat 120.
The threads 134 of the retainer 126 and the threads 136 of the valve body 102 are typically straight threads so that the retainer 126 can be accurately positioned relative to the valve body 102 and the diaphragm 112. However, because the threads 134, 136 are straight threads, high pressure fluid from the inlet 106 may flow between the threads 134, 136 to the sensing chamber 114, thereby causing impurities to flow in the fluid flow passageway. Further, some known fluid regulators may include a seal disposed below the threads 134, 136 on the inlet side 106 of the fluid flow passageway. However, vibration and/or pressure pulses across the fluid flow passageway may agitate debris or impurities between the threads 134, 136, causing the impurities to flow into the fluid flow passageway via the sensing chamber 114. In some instances, the orientation of the fluid regulator 100 may be such that gravity and/or vibration causes debris or impurities between the threads 134, 136 to flow into the fluid flow passageway. For example, if the fluid regulator 100 is oriented upside down, impurities between the threads 134, 136 may fall into the sensing chamber 114 due to gravity and/or vibration.
Further, although an NPT thread engagement can provide a seal between the engaging threads, an NPT thread instead of the straight threads 134, 136 may not be suitable because an NPT thread may cause the retainer 126 to be at an improper position (e.g., a height, a perpendicularity, etc.) relative to the valve body 102, thereby affecting the position of the poppet 118 relative to the valve seat 132 and, thus, a fluid flow rate for a given stroke position of the diaphragm 112. For example, if the retainer 126 is at a lower height relative to the valve body 308 than desired, the diaphragm 112 may have to be stroked a greater distance than necessary to obtain a desired fluid flow rate.
Further, a cleaning process may not be suitable after assembly of the fluid regulator 100 in some instances because a cleaning solution or solvent may not be completely removed from the fluid regulator 100 after cleaning. As a result, the solvent may interact with a process fluid (e.g., oxygen) in operation when the fluid regulator 100 is coupled to a process system.
The load assembly 320 is operatively coupled to the diaphragm 314 via a diaphragm plate or back-up plate 330 and provides a reference force or load (e.g., a pre-set force) to the diaphragm 314. In this example, the load assembly 320 includes a biasing element 332 (e.g., a spring) disposed within the load chamber 318 that provides a load to the diaphragm 314 via the diaphragm plate 330. The biasing element 332 seats between the diaphragm plate 330 and a spring button 334 that is operatively coupled to a spring adjustor 336 via a screw 338. The spring adjustor 336 moves the biasing element 332 via the spring button 334 to adjust (e.g., increase or decrease) the amount of a preset force or load that the biasing element 332 exerts on the first side 316 of the diaphragm 314. For example, rotation of the spring adjustor 334 in a first direction (e.g., a clockwise direction) or a second direction (e.g., a counterclockwise direction) varies the amount of compression of the biasing element 332 (e.g., compresses or decompresses the biasing element 332) and, thus, the amount of load exerted on the first side 316 of the diaphragm 314.
To control or modulate fluid flow between the inlet 310 and the outlet 312, the fluid regulator 300 employs the valve apparatus or valve cartridge 302. The valve apparatus 302 of the illustrated example is a subassembly that is disposed within a bore or opening 342 (e.g., a threaded opening) of the valve body 308 that defines an inlet chamber 344 fluidly coupled to the inlet 310. The valve apparatus 302 is operatively coupled to the diaphragm 314 such that the diaphragm 314 causes the valve apparatus 302 to move between an open position to allow fluid flow through the passageway of the fluid regulator 300 and a closed position to restrict fluid flow through the passageway of the fluid regulator 300 based on a pressure differential on opposing of the diaphragm 314 provided by the biasing element 332 and the pressure in the sensing chamber 326.
The housing 402 includes a cavity or bore 406 to at least partially define the fluid flow passageway when the valve apparatus 302 is coupled to the valve body 308. More specifically, when coupled within the fluid flow passageway of the fluid regulator 300, the valve apparatus 302 defines a high-pressure side 403 of the fluid flow passageway in fluid communication with the inlet 310 and a low-pressure side 405 of the fluid flow passageway in fluid communication with the outlet 312.
A movable valve or flow control assembly 408 is disposed within the bore 406 to control fluid flow between the inlet 310 and the outlet 312. In this example, the flow control assembly 408 includes a poppet 410, a valve seat 412, and a biasing element 414. The biasing element 414 is disposed between a shoulder 416 of the poppet 410 and a spring seat 418 to bias the poppet 410 toward the valve seat 412 (e.g., a closed position). The diaphragm 314 moves relative to (e.g., engages) a stem 413 of the poppet 410 to move the poppet 410 relative to the valve seat 412 to modulate or control fluid flow through the passageway.
To retain the flow control assembly 408 within the bore 406 of the housing 402, the valve apparatus 302 includes a cap 420. The cap 420 includes external threads 422 to threadably couple the cap 420 to an end 424 of the housing 402. In other examples, the cap 420 may be crimped onto the end 424 of the housing 402.
In this example, the valve apparatus 302 also includes a filter or filter cartridge 426 (e.g., a screen) coupled to the housing 402 such that the filter 426 is disposed within the inlet chamber 344. As shown, the filter 426 is disposed between the cap 420 and the valve seat 412 to filter impurities (e.g., debris, contaminates, etc.) in the fluid flowing to the inlet chamber 344 from the inlet 310. Thus, the cap 420 retains the filter 426 within the bore 406 of the housing 402. As shown, the filter 426 is a cylindrically-shaped sintered metal filter that substantially encompasses or surrounds the poppet 410. The filter 426 engages the valve seat 412 to retain the valve seat 412 against the shoulder 416 of the housing 402 to prevent fluid from the inlet chamber 344 from flowing past the valve seat 412.
To provide a seal between the sensing chamber 326 and the inlet chamber 344, the valve apparatus 302 includes a seal 428. The seal 428 (e.g., an O-ring) is disposed between the housing 402 of the valve apparatus 302 and the valve body 308 of the fluid regulator 300. Additionally, the seal 428 is disposed between the sensing chamber 326 and the threads 404 of the housing 402. In particular, the seal 428 is disposed on the low-pressure side 405 of the threads 404 (i.e., above the threads 404 in the orientation of
In the illustrated example, the housing 402 includes a flange 430 to retain the seal 428. Further, the flange 430 provides a positive stop that engages a surface 431 of the valve body 308 to provide a proper position or orientation (e.g., a height, perpendicularity, etc.) of the valve apparatus 302 relative to the valve body 308. Additionally, the threads 404 of the housing 402 and threads 434 of the opening 342 are straight threads so that valve apparatus 302 can be threaded to the opening 342 of the valve body 308 until the flange 430 engages the surface 431 of the valve body 308. Engagement of a surface 436 of the flange 430 with the surface 431 of the valve body 308 provides a proper position (e.g., a height, perpendicularity, etc.) of the valve apparatus 302 relative to the valve body 308. Thus, an NPT thread may not be suitable because such thread may prevent the flange 430 from engaging the surface 431. A proper position or orientation of the valve apparatus 302 provides a predicted flow rate across the orifice 408 for a given stroke position of the diaphragm 314. If the valve apparatus 302 is improperly positioned (e.g., at a height greater than or less than the position shown in
Additionally or alternatively, if the valve apparatus 302 is adjusted too high, the diaphragm 314 may engage the connector stem 413 and provide a pre-load condition to the poppet 410, which may provide a force on the poppet 410 to prevent the poppet 410 from sealingly engaging the valve seat 412 and causing fluid leakage across the valve seat 412. If the valve apparatus 302 is positioned too low (e.g., at a height that is lower than what is shown), the diaphragm 314 has to move or flex a greater amount or distance to move the poppet 410 away from the valve seat 412 to the open position, which may cause the diaphragm 314 to fail to due to stress or fatigue.
Further, the valve apparatus 302 of the illustrated example employs a non-threaded connection on the low-pressure side 405 of the fluid flow passageway to house or contain the flow control assembly 408 within the bore 406. In other words, the valve apparatus 302 of the illustrated example does not include internal threads on the valve apparatus 302 in fluid communication with the low-pressure side 405 that may introduce impurities or debris downstream of the filter 426 and contaminate the fluid flowing through the passageway, and/or cause damage to the valve seat 412 and/or the poppet 410. More specifically, the flow control assembly 408 is retained within the bore 406 of the housing 402 using a non-threaded connection downstream from the filter 426. For example, the poppet 410, the valve seat 412 and the biasing element 414 are held or retained within the bore 406 between the shoulder 416 of the housing 402 and the cap 420 when the cap 420 is threadably coupled to the housing 402. Further, the threads 422 of the cap 420 and threads 432 of the housing 402 are upstream from the filter 426 or adjacent a non-filtered side of the filter 426 and/or in communication with the high-pressure side 403. Thus, the seal 428 and the filter 426 isolate or prevent impurities formed by the threads 422 and 432 during assembly from flowing into the low-pressure side 403 of the passageway. Further, the seal 428 prevents impurities formed between the threads 404 of the valve apparatus 302 and threads 434 of the opening 342 of the valve body 308 during assembly from flowing into the low-pressure side 403 of the fluid flow passageway.
Referring to
To achieve a desired outlet pressure, the adjustor 336 is rotated (e.g., in a clockwise or counterclockwise direction) to increase or decrease the load exerted by the biasing element 332 on the first side 316 of the diaphragm 314. With the reference pressure set, the sensing chamber 326 senses a pressure of the pressurized fluid at the outlet 312 via the passage 328, which causes the diaphragm 314 to move in response to pressure changes in the sensing chamber 326 based on a pressure or force differential provided across the diaphragm 314 by the pressurized fluid in the sensing chamber 326 and the biasing element 332. A pressure differential across the diaphragm 314 causes the poppet 410 to move between a closed position at which the poppet 410 engages (e.g., sealingly engages) the valve seat 412 to restrict fluid flow between the inlet 310 and the outlet 312 and an open position at which the poppet 410 moves away from the valve set 412 to allow fluid flow between the inlet 310 and the outlet 312. The pressurized fluid flows between the inlet 310 and the outlet 312 until the pressures or forces on opposing sides of the diaphragm 314 are balanced.
Impurities (e.g., debris, contaminate or particulate) in the fluid and/or between the threads 404, 422 that may be produced during assembly of the valve apparatus 302 or the fluid regulator 300 flows toward the filter 426, which prevents or substantially restricts passage of impurities, particulate or contaminate into the fluid flow passageway. Also, the seal 428 prevents impurities within the threads 404 and/or the inlet chamber 344 from flowing in the fluid flow passageway via the sensing chamber 326. As a result, the seal 428 and the filter 426 capture or trap impurities upstream from the filter 426 and away from the fluid flow passageway. As a result, impurities in the fluid and/or that may form during assembly of the fluid regulator 300 settle within the inlet chamber 344 or are contained within the high-pressure side 403 of the fluid flow passageway. Additionally, the valve seat 412 and the poppet 410 are protected from impurities because the seal 428 and the filter 426 both prevent impurities from reaching or accumulating on the valve seat 412 and or the poppet 410.
Further, the valve apparatus 302 provides a non-threaded connection in fluid communication with the low-pressure side 405 of the fluid flow passageway. Thus, the valve assembly 302 does not form impurities downstream from the filter 426 when assembling the valve apparatus 302 to the fluid regulator 300.
The valve apparatus 302 of
Similar to the valve apparatus 302 of
Further, the valve apparatus 502 includes a non-threaded connection downstream from the filter 504. Thus, the filter 504 and the seal 526 trap or contain impurities upstream of the filter 504. In operation, the filter 504 and the seal 526 isolate impurities (e.g., produced by the external threads 518) upstream from the filter 504 and prevent impurities from flowing in the fluid flow passageway and/or accumulating on the fluid control apparatus 508.
Referring 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.
This patent arises as a continuation-in-part of U.S. patent application Ser. No. 12/496,868, filed on Jul. 2, 2009, entitled “BALANCED VALVE CARTRIDGE,” which is incorporated herein by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 12496868 | Jul 2009 | US |
| Child | 13052470 | US |
