Control Member for a Fluid Regulating Device

A control member for a fluid regulating device. The control member includes a top side and a bottom side. The top side is adapted to engage a valve seat of the fluid regulating device when the control member is arranged in a closed position. The control member also includes a means for reducing a suction force exerted on the bottom side of the control member by fluid flowing proximate to the control member. In one example, the means takes the form of a rim that extends outwardly from the bottom side to a position below the bottom side. The rim is configured to reduce a downward force exerted on the bottom side of the control member by directing fluid flowing through the fluid passageway away from the bottom side of the control member.

FIELD OF THE INVENTION

The present invention relates generally to fluid regulating devices such as fluid or gas regulators and, more specifically, to a control member for a fluid regulating device.

BACKGROUND

Regulators are commonly employed in fluid or gas distribution systems to control the pressure in the system downstream of the regulator. As is known, the pressure at which a typical gas distribution system supplies gas may vary according to the demands placed on the system, the climate, the source of the supply, and/or other factors. However, most end-user facilities equipped with gas appliances such as, for example, furnaces, and ovens, require the gas to be delivered in accordance with predetermined pressure parameters. Therefore, such distribution systems use gas regulators to ensure that the delivered gas meets the requirements of the end-user facilities.

Direct-operated fluid regulators are primarily designed for industrial and commercial applications supplying fluids, such as natural gas and propane, to furnaces, burners, and other appliances and are generally well known in the art. 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, fluid regulators commonly include a sensing element or diaphragm to sense an outlet pressure in fluid communication with a downstream pressure.

SUMMARY

In accordance with a first exemplary aspect of the invention, a control member for a fluid regulating device is provided. The control member includes a top side adapted to engage the valve seat when the control member is arranged in a closed position, a bottom side, and a means for reducing a suction force exerted on the bottom side of the control member by fluid flowing proximate to the control member.

In accordance with a second exemplary aspect of the invention, a control member for a fluid regulating device is provided. The control member includes a top side, a bottom side, and a rim. The top side is adapted to engage a valve seat of the fluid regulating device when the control member is arranged in a closed position. The rim extends outwardly from the bottom side to a position below the bottom side. The rim is configured to reduce a downward force exerted on the bottom side of the control member by directing fluid flowing through the fluid passageway away from the bottom side of the control member.

In accordance with a third exemplary aspect of the invention, a fluid regulating device is provided. The fluid regulating device includes a valve body, an actuator assembly coupled to the valve body, a valve seat, and a stem assembly. The valve body has an inlet, an outlet, and a fluid passageway defined between the inlet and the outlet. The actuator assembly includes an upper casing, a lower casing secured to the upper casing, and a diaphragm assembly disposed between the upper casing and the lower casing. The valve seat is disposed in the valve body along the fluid passageway. The stem assembly is operatively connected to the diaphragm assembly to move with the diaphragm assembly. The stem assembly includes a valve stem and a control member operatively connected to the valve stem and movable relative to the valve seat to control fluid flow through the fluid passageway. The control member includes a body having a top side configured to engage the valve seat when the control member is in a closed position and a bottom side. The control member further includes a rim extending outwardly from the body to a position below the bottom side. The rim configured to direct fluid flowing through the fluid passageway away from the bottom side of the control member.

In accordance with a fourth exemplary aspect of the invention, a fluid regulating device is provided. The fluid regulating device includes a valve body, an actuator assembly coupled to the valve body, a valve seat, and a stem assembly. The valve body has an inlet, an outlet, and a fluid passageway defined between the inlet and the outlet. The actuator assembly includes an upper casing, a lower casing secured to the upper casing, and a diaphragm assembly disposed between the upper casing and the lower casing. The valve seat is disposed in the valve body along the fluid passageway. The stem assembly is operatively connected to the diaphragm assembly to move with the diaphragm assembly. The stem assembly includes a valve stem and a control member operatively connected to the valve stem and movable relative to the valve seat to control fluid flow through the fluid passageway. The control member comprises a top side configured to engage the valve seat when the control member is in a closed position, a bottom side, and a perimeter edge. The perimeter edge has a first portion between the top and bottom sides and a second portion extending outwardly from the first portion to a position below the bottom side. The second portion configured to direct fluid flowing through the fluid passageway away from the bottom side of the control member.

In further accordance with any one or more of the foregoing first, second, third, or fourth exemplary aspects, a control member and/or a fluid regulating device may include any one or more of the following further preferred forms.

In one preferred form, the means for reducing a suction force exerted on the bottom side of the control member includes a rim extending outwardly from the bottom side to a position below the bottom side. The rim is configured to reduce a downward force exerted on the bottom side of the control member by directing fluid flowing through the fluid passageway away from the bottom side of the control member.

In another preferred form, the rim is radially aligned with a circumferential edge of the body of the control member.

In another preferred form, the control member includes a body including the top side and the bottom side. The means for reducing a suction force exerted on the bottom side of the control member extends outwardly from the body to a position below the bottom side.

In another preferred form, the control member includes a body having a first annular portion and a second annular portion having a diameter greater than a diameter of the first annular portion, and the means for reducing a suction force exerted on the bottom side of the control member includes the second annular portion.

In another preferred form, the control member includes a body having a perimeter edge, and the means for reducing a suction force exerted on the bottom side of the control member includes a portion of the perimeter edge.

In another preferred form, a fastener connects the control member to the valve stem. The fastener can be recessed within the control member.

In another preferred form, a through-bore is formed through the control member, and a fastener that connects the control member to the valve stem is arranged in the through-bore between the top and bottom sides of the control member.

In another preferred form, a through-bore is formed through the control member. The through-bore is configured to receive a fastener for connecting the control member to the valve stem.

In another preferred form, the rim circumferentially surrounds the bottom side of the control member.

In another preferred form, the second portion of the perimeter edge circumferentially surrounds the bottom side of the control member.

In another preferred form, the second portion of the perimeter edge has a diameter greater than a diameter of the first portion of the perimeter edge.

In another preferred form, the second portion of the perimeter edge is radially aligned with the first portion of the perimeter edge.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1illustrates a fluid regulator10that generally includes an actuator assembly100and a valve body200. The actuator assembly100is coupled (e.g., secured) to the body200with threaded studs400and locknuts405, though the actuator assembly100can be coupled to the body200by any other well-known means.

The actuator assembly100has an upper casing110coupled to a lower casing120with nuts410and bolts415, or any other well-known means, which when assembled define a cavity140. A diaphragm assembly150, as described in more detail below, is secured between upper casing110and lower casing120, and divides the cavity140into an upper portion142above the diaphragm assembly150and a lower portion144below the diaphragm assembly150.

The upper casing110has a cylindrical wall112extending therefrom. The cylindrical wall112has a threaded inner surface113and defines an opening114in one end. An adjusting screw160is threaded into the cylindrical wall112of upper casing110and a closing cap170is threaded into the opening114of the cylindrical wall112to protect adjusting screw160and prevent debris from entering actuator assembly100. A spring180is disposed in an upper portion142of cavity140between the adjusting screw160and the diaphragm assembly150to bias the diaphragm assembly150toward the body200. Another opening116is also formed in upper casing110to fluidly couple the upper portion142of cavity140with the atmosphere. In the particular example shown, a stabilizer assembly118, which is well-known in the art, is disposed proximate the opening114to control the flow of fluid into and out of the upper portion142of cavity140through the opening116.

The lower casing120has a wall122extending therefrom. The wall122has a cylindrical inner surface128that ends at a shoulder and defines a portion of balancing cavity126. A flange124extends outward from the wall122and has apertures to receive threaded studs400. A threaded opening132is also formed in lower casing120and can be used to connect the lower casing120to an external control line (not shown), which can be used to fluidly couple the lower portion144of the cavity140and a downstream pipe, as discussed in more detail below.

The diaphragm assembly150generally includes a diaphragm152, a diaphragm plate154, a spring seat156, and top and bottom sealing washers158,159. The diaphragm152is secured at its outer edge between upper casing110and lower casing120and has an opening formed in the center to receive a stem242of a stem assembly240. The diaphragm plate154is positioned adjacent the diaphragm152to provide support to the inner portion of diaphragm152. The spring seat156is positioned adjacent the diaphragm plate154to receive one end of spring180. Top and bottom sealing washers158,159are positioned on opposite sides of diaphragm152to secure the diaphragm152and the diaphragm plate154to the stem242, as described in more detail below, and to provide a seal to prevent fluid flow between the upper portion142and the lower portion144of cavity140through the opening in the diaphragm152.

The body200defines a fluid inlet212, a fluid outlet214, and a fluid passage216fluidly connecting the inlet212and the outlet214. An opening218is formed in the body200and is in fluid communication with the inlet212and aligned with the fluid passage216. The regulator10also includes a seat insert220, a cage230, and the stem assembly240. The seat insert220is secured in the fluid passage216and provides or defines a seating surface222. The cage230is positioned in the opening218and has a top wall232, a generally cylindrical side wall236that extends from one side of top wall232and defines a second portion of the cylindrical balancing cavity126, and a plurality of support legs238that extend from another side of top wall232, opposite side wall236, to support cage230on the body200. An aperture234is formed through a central portion of top wall232to receive a sleeve250of the stem assembly240.

The stem assembly240generally includes the stem242, the sleeve250, the control member260, and a registration disk262. The stem242is a generally cylindrical rod that extends through an aperture in the lower casing120and has a first threaded end244that extends through openings in the bottom sealing washer159, the diaphragm152, the diaphragm plate154, the spring seat156, and the top sealing washer158. The bottom sealing washer159engages a shoulder245formed on the stem242and a nut270is threaded onto first threaded end244to compress the bottom sealing washer159, the diaphragm152, the diaphragm plate154, the spring seat156, and the top sealing washer158between shoulder245and nut270, and secure the diaphragm assembly150to the stem assembly240. The sleeve250is positioned over a portion of the stem242to provide an annular space252between the stem242and the sleeve250from a bottom end of sleeve250to an area proximate a hole248formed through the stem242, and extends through the aperture234in the cage230. The control member260, which in this example is a valve disk, is positioned over an end of the sleeve250and the registration disk262is positioned over a second threaded end246of the stem242, adjacent the control member260. The control member260and registration disk262are secured to the stem242and the sleeve250by a nut280. The control element260is thus operatively coupled to the stem242, such that the control element260is, responsive to movement of the stem242, movable relative to the seating surface222to control fluid flow through the fluid passage216. More specifically, the control member260is movable between a closed position, wherein the control member260sealingly engages the seating surface222to prevent fluid flow through the fluid passage216, and an open position, wherein the control member260is spaced from the seating surface222and fluid can flow through the fluid passage216.

In operation, when the control member260is in an open position (i.e., spaced away from the seating surface222), process fluid enters the body200through the inlet212at an inlet pressure, and flows through the seat insert220, past control member260, and exits the body200through the outlet214at a downstream pressure. A portion of the fluid at downstream pressure P2flows through the external control line (not shown) and is communicated to the lower portion144of cavity140through the opening132in the lower casing120. Increased demand for the operating fluid at the outlet214will cause the downstream pressure to decrease, which will decrease the pressure in the lower portion144of the cavity140, and, in turn, the upward pressure exerted on the diaphragm152, thereby allowing the spring180to move the diaphragm152and stem assembly240downward. This, in turn, opens the control member260further (i.e., moves the control member260further away from the seating surface222) and supplies more operating fluid to the system to meet the increased demand. Conversely, decreased demand for the operating fluid at the outlet214will cause the downstream pressure to increase, which will increase the pressure in the lower portion144of the cavity140, and, in turn, the upward pressure exerted on the diaphragm152, thereby moving the diaphragm152and stem assembly240upward. This, in turn, closes the control member260further (i.e., moves the control member260closer to the seating surface222) to decrease the supply of the operating fluid to the system to meet the decreased demand.

When the regulator10is operating at steady-state conditions, the stabilizers of stabilizer assembly118are closed and only a small hole is open to stabilize normal operation. When the regulator10responds to an increase in downstream pressure, the pressure in the lower portion144of the cavity140increases and the diaphragm152moves upward. As diaphragm152moves upward, movement of air in the upper portion142of the cavity140can force a lower vent stabilizer of the stabilizer assembly118upward, which allows the air in the upper portion142of the cavity140to vent to the atmosphere rapidly and minimize any lag in movement of the diaphragm152. When the regulator10responds to a decrease in downstream pressure, the pressure in the lower portion144decreases and the diaphragm152moves downward. As the diaphragm152moves downward, air rushes through the stabilizer assembly118to fill the partial vacuum created in the upper portion142of the cavity140, which forces an upper vent stabilizer of the stabilizer assembly118to close. Air flowing through webs of the upper vent stabilizer can then open the lower vent stabilizer to allow air from the atmosphere to flow into the upper portion142of the cavity140.

When the control member260is open, the process fluid flows from inlet212, through seat insert220(and thus the fluid passage218), and over the edge of the control member260to outlet214. As the process fluid flows through the seat insert220and over the edge of the control member260, the process fluid may exert an upward or downward force on the control member260, which can in turn interfere with the operation of the regulator10by counteracting or adding to the upward force applied by the outlet pressure on the diaphragm152. This is particularly problematic in high flow situations, whereby the process fluid, flowing or traveling at high velocities on the flat underside of the control member260, generates a suction (i.e., downward) force that acts to move the control member260further away from the seating surface222than desired, thereby opening the regulator10more than desired. This is also problematic when the regulator10operates at low outlet pressures, whereby even a small suction force generated by the process fluid flowing or traveling on the flat underside of the control member260can act to move the control member260further from the seating surface222than desired. In both situations, the downstream outlet pressure may be boosted out of accuracy, thereby limiting the capacity of the regulator10.

The present disclosure thus provides a control member500that, when implemented in the regulator10, minimizes the suction force generated by the process fluid in high flow situations and at low outlet pressures, thereby reducing, if not removing, undesirable “boost”, and improving the accuracy of the regulator10. To this end, the control member500is generally constructed so that high-velocity fluid flow is substantially kicked off, or directed away from, the underside of the valve member500. This can be accomplished in any number of different ways, as will be described below.

FIGS. 2A and 2Billustrate one example of such a control member500, taking the form of a valve pad600. The valve pad600has a body602defined by a top side or surface604, a bottom side or surface608, and a circumferential edge612between the top side604and the bottom side608. The valve pad600also includes a downwardly extending rim or lip616, which can be integrally formed with the body602or can be separately manufactured and subsequently coupled to the body602. The rim or lip616extends from a portion of the body602(e.g., the circumferential edge612) to a position below the bottom side608. The circumferential edge612and the rim616can, but need not, have a combined length L that is greater than the diameter D of the valve pad600. In the illustrated example, the rim or lip616is radially aligned with the circumferential edge612, such that the circumferential edge612and the rim616have the same diameter. In other examples, however, the rim or lip616can be positioned radially inward or radially outward of the circumferential edge612.

As best illustrated inFIG. 2B, the valve pad600has a through-bore620formed therethrough along a central longitudinal axis624of the pad600. The through-bore620is sized to receive an end628of the stem242. The end628of the stem242is, in this example, threaded, such that a fastener632(e.g., a retaining nut) with a threaded inner surface can be threaded onto the stem242to couple (e.g., fixedly secure) the stem242to the valve pad600, as is illustrated inFIG. 2B. It will be appreciated that the fastener632is, as a result of the structure of the valve pad600, recessed within the valve pad600.

When the valve pad600is so coupled to the stem242, and the regulator10is in operation, the valve pad600minimizes the suction force that would otherwise be generated by the process fluid in high flow situations and at low outlet pressures. When the valve pad600is open, such that the process fluid flows from the inlet212and through the seat insert220(and thus the fluid passage218), the process fluid will flow along the circumferential edge612and the rim or lip616to the outlet214. While some process fluid may, in the process, reach the bottom surface608of the valve pad600, the rim or lip616will keep or direct most of the process fluid flow away from the bottom surface608of the valve pad600(i.e., the underside of the valve pad600). As a result, only a minimal amount of suction force will be generated by the process fluid and exerted on the bottom surface608of the valve pad600, even in high flow situations and at low outlet pressures. In turn, the valve pad600helps to reduce unnecessary and undesirable “boost”, facilitating a more accurate pressure regulator10. Moreover, by recessing the fastener632(i.e., the connection between the stem242and the valve pad600) within the valve pad600, the fastener632is substantially not exposed to the process fluid flowing through the regulator10. This also helps to reduce the suction force that would otherwise be generated by process fluid flowing across the bottom of the fastener632, particularly when the process fluid is flowing at high velocities.

It will be appreciated that the control member500can vary and still facilitate a more accurate regulator10, as intended. The control member500can, in some examples, take the form of a valve plug, a valve disc, or other type of control member. The control member500can vary in shape, size, and/or construction. As illustrated inFIG. 3, for example, the control member500can take the form of a stepped valve pad700having a plurality of (in this case, two) differently sized annular portions704,708. The first annular portion704defines a top side or surface712and the second annular portion708defines a bottom side or surface716. The second annular portion708has a larger diameter than the first annular portion704, such that process fluid flowing through the regulator10is largely kept or directed away from the bottom surface716, thereby minimizing the amount of suction force generated by the process fluid and exerted on the bottom surface716. Moreover, instead of including the rim or lip616, the control member500may kick process fluid off the bottom surface608by utilizing a concave-shaped bottom surface608, a different shape for the bottom surface608, or by utilizing other features that accomplish the same function. Further yet, in some cases, the amount of “boost” provided by the control member500may be increased or decreased, as desired based on the given application, by adjusting the height of the rim616, the diameter of the control member500, the castling of the rim616, or in some other manner.

Turning now toFIG. 4, the performance of a fluid regulating device outfitted with a conventional control member, such as the control member260, will now be compared with the performance of a fluid regulating device outfitted with a control member constructed in accordance with the teachings of the present invention, such as the valve pad600or the valve pad700.

FIG. 4illustrates two flow curves ((1) and (2)) of a fluid regulating device with a conventional control member, such as the control member260, two flow curves ((3) and (4)) of a regulator with a control member constructed in accordance with the teachings of the present invention, such as the valve pad600, and two flow curves ((5) and (6)) of a fluid regulating device with another control member constructed in accordance with the teachings of the present invention, such as the valve pad700. In each of the tests represented by the data shown in the graph provided inFIG. 4, the fluid regulating device was set with an inlet pressure of 87 pounds per square inch gage (psig) and the outlet pressure P2was measured as a function of the flow rate. The y-axis of the graph shown inFIG. 4corresponds to the measured outlet pressure P2, measured in psig, and the x-axis of the graph shown inFIG. 4corresponds to the flow rate in standard cubic feet per hour (scfh). As seen in theFIG. 4graph, the output pressure P2is similar for each of the fluid regulating devices at low flow rates (0-50,000 scfh), but spikes, or dramatically increases, at higher flow rates (50,000-250,000 scfh) for the fluid regulating device with the conventional control member. This spike is the result of the suction force generated by fluid flowing at high velocities along the underside of the control member260. Meanwhile, the output pressure P2is relatively stable, even at higher flow rates, for the fluid regulating devices with the control members constructed in accordance with the teachings of the present invention. This increased stability, which provides for a more accurate fluid regulating device, is an unexpected result of kicking fluid flow off of the underside of the control member and recessing the fastener, which connects the stem and the control member, within the control member.

From the foregoing, it can be seen that the present disclosure advantageously provides an improved control member for a fluid regulating device that effectively reduces the suction force generated by process fluid flowing through the fluid regulating device. This reduction advantageously increases the stability of the output pressure of the fluid control device, which thereby improves the accuracy of the fluid regulating device.

Preferred embodiments of this invention are described herein, including the best mode or modes known to the inventors for carrying out the invention. Although numerous examples are shown and described herein, those of skill in the art will readily understand that details of the various embodiments need not be mutually exclusive. Instead, those of skill in the art upon reading the teachings herein should be able to combine one or more features of one embodiment with one or more features of the remaining embodiments. Further, it also should be understood that the illustrated embodiments are exemplary only, and should not be taken as limiting the scope of the invention. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended merely to better illuminate the aspects of the exemplary embodiment or embodiments of the invention, and do not pose a limitation on the scope of the invention. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.