Fluid flow control devices and systems

CROSS-REFERENCE TO RELATED APPLICATION(S)

0001The present application claims the benefit of U.S. Application No. 62/022,851, filed Jul. 10, 2014.

TECHNICAL FIELD

0002The present disclosure relates to a fluid flow control devices and systems.

BACKGROUND

0003When using conventional fluid flow control devices near minimum flow or shutoff, a number of factors including: duct configuration, turbulence, leakage, etc., can cause the internal mechanism to become unstable. This can result in inaccurate fluid flow through the device.

0004In some instances, the rate of fluid flow through the device can change drastically as the regulator closes the valve. Additionally, the internal mechanism can produce undesirable sounds and flexing of the duct which could result in damage to the valve and/or duct that would result in leakage or incorrect flows.

BRIEF DESCRIPTION OF THE DRAWINGS

0005<figref idref="DRAWINGS">FIG. 1</figref> is a cutaway view of a fluid flow valve embodiment of the present disclosure.

0006<figref idref="DRAWINGS">FIG. 2</figref> is partial cutaway view of a fluid flow regulator of an embodiment of the present disclosure.

0007<figref idref="DRAWINGS">FIG. 3</figref> is partial cutaway view of a damping mechanism of an embodiment of the present disclosure.

DETAILED DESCRIPTION

0008The present disclosure relates to fluid flow control devices and systems, for example, to reduce or alleviate instability that are described herein. The embodiments of the present disclosure can be utilized to control the fluid flow through the conduit, particularly when the device is in a nearly closed condition or is just starting to open.

0009Embodiments of the present disclosure provide a damping mechanism that allows the valve to close without becoming unstable which may lead to the fluid flow being inconsistent, the regulator abruptly stopping and starting, and/or the regulator banging on the side of the conduit or a stopping surface thereon, among other benefits. An embodiment of the present disclosure is provided in <figref idref="DRAWINGS">FIGS. 1-3</figref> and discussed herein.

0010The figures herein follow a numbering convention in which the first digit or digits correspond to the drawing figure number and the remaining digits identify an element or component in the drawing. Similar elements or components between different figures may be identified by the use of similar digits. For example, <b>108</b> may reference element “08” in <figref idref="DRAWINGS">FIG. 1</figref>, and a similar element may be reference by <b>208</b> in <figref idref="DRAWINGS">FIG. 2</figref>. As used herein, “a” or “an” refer to one or more. For example, “an element” can refer to one or more element.

0011<figref idref="DRAWINGS">FIG. 1</figref> is a cutaway view of a fluid flow valve embodiment of the present disclosure. In the embodiment of <figref idref="DRAWINGS">FIG. 1</figref>, the flow control device <b>100</b> controls the flow of fluid through a conduit <b>101</b>. As used herein, the term “valve” generally refers to the flow control device. Further, as used herein, the term “conduit” describes a housing having a passage for the flow of a fluid through the conduit (e.g., the fluid enters the conduit at a first end and exits the conduit at a second end.

0012The device <b>100</b> is typically attached in a duct or piping system where the conduit <b>101</b> is connected to a portion of the duct or piping at a first end and fluid flows from the pipe or duct into the conduit <b>101</b>. In such an arrangement, the conduit <b>101</b> is also connected to the duct or piping at the second end and the flow of fluid exits the conduit <b>101</b> and continues flowing in the pipe or duct system.

0013The device <b>100</b> includes a conduit body having an axis (along which the shaft <b>114</b> is axially aligned) and defining a passage that allows fluid to flow from an upstream position <b>103</b>-<b>1</b> to a downstream position <b>103</b>-<b>2</b> (illustrated by the straight arrows in the upstream position and the downstream position). The body has a converging portion <b>102</b> in the upstream position with an inner surface that curves gradually inward and a diverging portion <b>104</b> wherein the sides (in the example of <figref idref="DRAWINGS">FIG. 1</figref>, the conduit has a circular cross-section and, therefore, has only one continuous side, however, the shape of the conduit can differ in various embodiments and may have more than one side) of the conduit <b>101</b> expand outward from the axis. The transition between the converging and diverging portions is referred to herein as the throat.

0014A flow regulator <b>106</b> is supported within the conduit for controlling the flow of fluid through the conduit <b>101</b>. The shaft <b>114</b> is provided onto which a flow regulator <b>106</b> is mounted. In the embodiment of <figref idref="DRAWINGS">FIG. 1</figref>, the shaft <b>114</b> passes through the passage of the conduit <b>101</b> and through the body of the flow regulator <b>106</b>. The shaft <b>114</b> is axially movable by a control mechanism (not shown). In this manner the regulator can be automatically or manually positioned (e.g., electrically, mechanically, or pneumatically) in one or more upstream initial positions that are closer or further away from the upstream end of the conduit.

0015A resilient mechanism <b>110</b> within the flow regulator <b>106</b> may, for example, is mounted on the shaft <b>114</b> to bias the flow regulator <b>106</b> toward a pre-determined position. The resilient mechanism <b>110</b> allows for the flow regulator <b>106</b> to move axially with respect to the shaft <b>114</b> in response to fluid flow variations such that a substantially constant volume of fluid will pass through the passageway of the body. In this manner, the resilient mechanism in the flow regulator body can be configured to reduce or eliminate oscillations of the flow regulator as an annular seating surface of the regulator approaches an annular rim of the conduit, as will be discussed in more detail below.

0016With respect to the conduit <b>101</b>, constant volume control may be provided by the axial movement of the regulator <b>106</b>. The regulator is mounted on an assembly that includes the shaft <b>114</b>, support members <b>116</b>-<b>1</b> and <b>116</b>-<b>2</b> that maintain the shaft in an axial orientation and allow the shaft to slide in an axial direction. The regulator <b>106</b> is mounted on the shaft <b>114</b> and has a smoothly increasing contour along its upstream side.

0017The largest diameter of the regulator is positioned proximate to the converging portion of the conduit to create an annular orifice. The regulator <b>106</b> moves axially on the shaft to increase or decrease the orifice area of the passage between the regulator and the side of the conduit.

0018The resilient mechanism <b>114</b> biases the regulator <b>106</b> in an axial position against a resilient mechanism stop position (i.e., wherein the resilient mechanism is fully compressed and cannot compress any further) such that when fluid flows through the valve, a pressure force across the valve moves the regulator back and forth to maintain a constant volume flow through the valve.

0019Thus, when the pressure drop across the valve increases, the regulator is pushed further toward the throat of the valve to reduce the area of the orifice and thus attempt to maintain a constant volume of fluid flowing though the valve. Similarly, when the pressure drop decreases the regulator moves away from the throat and the orifice opens to attempt to maintain a constant volume of fluid flow.

0020As discussed above, in some embodiments, the shaft <b>114</b> is axially movable by an actuator so that the flow volume may be adjusted automatically by electronic control, for example. Typically, operating requirements of the fluid control system may make changing the volume flow desirable. For example, in a laboratory fluid control system, discussed in detail below, raising a fume hood sash will typically require a shaft adjustment so that more fluid will flow through the valve to provide a relatively constant face velocity across the sash opening.

0021The diverging portion <b>104</b> of the conduit body preferably has an outwardly tapered configuration that begins at the throat and extends until the diameter of the surface extends to the nominal diameter at the second end of the conduit body. As shown in <figref idref="DRAWINGS">FIG. 1</figref>, the diverging portion is located at a downstream position <b>103</b>-<b>2</b> of the conduit <b>101</b>. Although a frusto-conical configuration is illustrated, other shapes would also be suitable such as a square, a rectangle or an oval, as would be apparent to those skilled in the art.

0022The assembly also includes a second resilient mechanism <b>108</b> that is spaced from the regulator <b>106</b> by a spacer <b>112</b>. This resilient mechanism can be utilized to damp the movement of the regulator as the regulator approaches a fully closed configuration, wherein the passage between the regulator and the conduit allows little to no flow through the passage, such as is shown in <figref idref="DRAWINGS">FIG. 1</figref>.

0023The resilient mechanism can also be utilized, in some embodiments, to damp the movement of the regulator as the regulator launches from a fully closed configuration to a more open configuration, wherein the passage between the regulator and the conduit begins to allow more flow through the passage. This can make the flow more consistent as it transitions from closed to open.

0024<figref idref="DRAWINGS">FIG. 2</figref> is partial cutaway view of a fluid flow regulator of an embodiment of the present disclosure. <figref idref="DRAWINGS">FIG. 2</figref> is an enlarged view of the portion of the conduit of <figref idref="DRAWINGS">FIG. 1</figref> having the regulator <b>106</b>. In <figref idref="DRAWINGS">FIG. 2</figref>, the regulator <b>206</b> has a resilient mechanism <b>210</b> with a number of mechanical parts.

0025Although shown as a mechanical apparatus, the resilient mechanism can also be made from a resilient material such as rubber, foam, or other such materials that can provide a damping functionality to the flow control device. Additionally, although shown with a spring and piston design, other mechanical mechanisms that provide damping functionality can be utilized with embodiments of the present disclosure. For example, in some embodiments, a pneumatic or electromechanical mechanism can be utilized for either or both of the first and/or second resilient mechanism.

0026With respect to the embodiment of <figref idref="DRAWINGS">FIG. 2</figref>, the resilient mechanism includes a cylinder <b>216</b> having two end caps <b>218</b> and <b>220</b>. The end caps allow the interior space of the cylinder to maintain air or other fluid within the cylinder to provide some damping properties. In some embodiments, the cylinder may not be completely air tight, but may allow air to leak out as the piston is compressed and then allow air to be pulled back in as the piston expands.

0027In the embodiment of <figref idref="DRAWINGS">FIG. 2</figref>, the shaft <b>214</b> passes through a hole in the end cap <b>218</b> and is attached to the piston body <b>224</b>. The piston body has a diameter and circumferential shape to restrict the amount of fluid within the cylinder to pass around the piston body and the side of the cylinder. In such a manner, the piston damps the movement of the regulator <b>206</b>. The cylinder <b>210</b> also includes a resilient portion (e.g., spring <b>222</b>) therein that biases against the movement of the piston and forces the piston back to a pre-determined initial position within the cylinder when pressure from the fluid within the passage of the conduit is not present or, in some applications, is at a low flow level. In this manner, the regulator can adjust its position based on the amount of fluid pressure in the passage of the conduit.

0028<figref idref="DRAWINGS">FIG. 2</figref> also illustrates the annular seating surface <b>226</b> of the regulator <b>206</b> and the annular rim <b>228</b> of the body of the conduit. It is these surfaces that when interacting, can reduce or in some embodiments, shut off the flow of fluid in the passage.

0029For example, if these surfaces are complementary around their circumference, then the flow can be shut off or nearly shut off depending on how closely they are engaged. If there is some places where they are not complementary (their surfaces do not contact to close the passage completely) between the two surfaces, then some air will be able to pass between them and the flow of fluid will be at a minimum level, but not shut off completely.

0030In some embodiments, the annular rim is positioned at the transition between the converging and diverging portions. In this manner, the regulator can have a smaller diameter than if the annular rim were positioned at a location farther upstream.

0031Additionally, <figref idref="DRAWINGS">FIG. 2</figref> provides an additional end cap <b>230</b> that can be used to keep debris out of the cylinder <b>210</b> and can interface with the spacer, as will be discussed in more detail below. The end cap <b>230</b> can be made from a rigid material, such as metal or plastic, or can be made from a resilient material, such as rubber or foam.

0032<figref idref="DRAWINGS">FIG. 3</figref> is partial cutaway view of a damper mechanism of an embodiment of the present disclosure. <figref idref="DRAWINGS">FIG. 3</figref> is an enlarged view of the portion of the conduit of <figref idref="DRAWINGS">FIG. 1</figref> having the second resilient mechanism <b>108</b> and spacer <b>112</b>.

0033In the embodiment of <figref idref="DRAWINGS">FIG. 3</figref>, the second resilient mechanism includes a cylinder <b>332</b> having two end caps <b>334</b> and <b>336</b>. As with the first resilient mechanism, the end caps allow the interior space of the cylinder to maintain air or other fluid within the cylinder to provide some damping properties. Also as discussed above, in some embodiments, the cylinder may not be completely air tight, but may allow air to leak out as the piston is compressed and then allow air to be pulled back in as the piston expands.

0034In the embodiment of <figref idref="DRAWINGS">FIG. 3</figref>, the shaft <b>314</b> passes through a hole in the end caps <b>334</b> and <b>336</b>, however, in the mechanism, the shaft <b>314</b> is not attached to the piston body <b>342</b>. Rather, the spacer <b>312</b> passes through the end cap <b>334</b> and contacts the piston body <b>342</b> to move the piston body. The spring <b>340</b> provides a biasing force against the force form the spacer to move the piston body <b>342</b> to a predetermined initial position.

0035As with the first resilient mechanism, the piston body <b>342</b> has a diameter and circumferential shape to restrict the amount of fluid within the cylinder to pass around the piston body and the side of the cylinder. In such a manner, the piston damps the movement of the regulator.

0036However, the second resilient mechanism only damps the movement of the regulator when the spacer is in contact with the regulator as shown in <figref idref="DRAWINGS">FIG. 1</figref> (e.g., when an engagement surface of the body of the regulator, such as a surface of the end cap <b>220</b> or, if used, end cap <b>330</b> contacts the spacer <b>312</b>).

0037In the embodiment shown in <figref idref="DRAWINGS">FIG. 1</figref>, the spacer is sized such that the interaction between it and the regulator will only occur when the regulator is near its fully closed position. Accordingly, in such embodiments, the second resilient mechanism can be utilized to damp the movement of the regulator as the regulator approaches a fully closed configuration, wherein the passage between the regulator and the conduit allows little to no flow through the passage, such as is shown in <figref idref="DRAWINGS">FIG. 1</figref>.

0038The second resilient mechanism can also be utilized, in some embodiments, to damp the movement of the regulator as the regulator launches from a fully closed configuration to a more open configuration, wherein the passage between the regulator and the conduit begins to allow more flow through the passage. This can make the flow more consistent as it transitions from closed to open.

0039Provided below is an example embodiment of the present disclosure. In this embodiment, a flow control device that controls the flow of fluid through a conduit includes a body having a passage that allows fluid to flow from an upstream position to a downstream position. The valve body has a converging portion in an upstream position with an inner surface that curves gradually inward and a throat between the converging portion and a diverging portion in the downstream position. The device also includes a flow regulator supported within the body for controlling the flow of fluid through the conduit the flow regulator, wherein the flow regulator has a body and wherein the body includes a first resilient mechanism configured to reduce or eliminate oscillations of the flow regulator as the flow regulator moves toward the downstream position.

0040As discussed herein, the inner surface that curves gradually inward, can have an annular rim formed by a portion that extends outward from the inward curving shape and wherein the flow regulator has an annular seating surface configured to contact the annular rim of the body.

0041In some such embodiments, the first resilient mechanism includes a cylinder having a resilient portion (e.g., a spring, or resilient material such as, rubber or foam, for instance) and a piston body within the cylinder. A resilient mechanism can be mounted on a shaft and the mechanism can be utilized to bias the flow regulator in a predetermined position, the resilient mechanism allowing the flow regulator to move axially with respect to the shaft in response to fluid flow variations through the passage such that a constant volume of fluid may pass through the passage of the valve body. As discussed herein, the device can also include a second resilient mechanism in the passage that is configured to dampen (e.g., retard the movement of) the movement of the flow regulator as the flow regulator moves toward the downstream position.

0042In some embodiments, the device can include a spacer positioned between the first resilient mechanism and the second resilient mechanism. As discussed, the spacer can be used to space the regulator from the second resilient mechanism. In some embodiments, the spacer passes through one end of the second resilient mechanism and contacts a piston within a cylinder of the second resilient mechanism. The spacer can be positioned between an exterior surface of the flow regulator and the second resilient mechanism.

0043Similarly with respect to the first resilient mechanism, the second resilient mechanism can include a cylinder having a resilient portion and a piston body within the cylinder.

0044Provided below is an example embodiment of the present disclosure. In this embodiment, a flow control device that controls the flow of fluid through a conduit includes a conduit body having a passage that allows fluid to flow from an upstream position to a downstream position, the valve body having a converging portion in the upstream position with an inner surface that curves gradually inward, but having an annular rim formed by a portion that extends outward from the inward curving shape, and a throat between the converging and diverging portions. The embodiment also includes a flow regulator supported within the body for controlling the flow of fluid through the conduit the flow regulator, the flow regulator having an annular seating surface configured to contact the annular rim of the body, and wherein the flow regulator has a body and wherein the body includes a first resilient mechanism configured to reduce or eliminate oscillations of the flow regulator as the flow regulator moves toward the downstream position.

0045In some embodiments, the flow regulator body has a diameter such that the body will not pass through the smallest diameter of the passage. In this manner, the flow through the passage of the conduit can be completely shut off, in some embodiments. As discussed above, in some embodiments, the system can include a second resilient mechanism in the passage that is configured to dampen the movement of the flow regulator as the flow regulator moves toward the downstream position.

0046Embodiments of the present disclosure can be of any size and/or used in multiple valve combinations (e.g., dual, triple, quad, etc.). In such multiple valve combination embodiments, one or more of the valves can be embodiments of the present disclosure.

0047The embodiments of the present disclosure are described in sufficient detail to enable those of ordinary skill in the art to practice one or more embodiments of this disclosure. It is to be understood that other embodiments may be utilized and that process and/or structural changes may be made without departing from the scope of the present disclosure.

0048As will be appreciated, elements shown in some embodiments herein can be added, exchanged, combined, and/or eliminated so as to provide a number of additional embodiments of the present disclosure. The proportion and the relative scale of the elements provided in the figures are intended to illustrate the embodiments of the present disclosure, and should not be taken in a limiting sense.