Patent Application
20070267588
The accompanying drawings incorporated in and forming a part of the specification illustrate several aspects of the present invention and, together with the description, serve to explain the principles of the invention. In the drawings:
While the invention will be described in connection with certain preferred embodiments, there is no intent to limit it to those embodiments. On the contrary, the intent is to cover all alternatives, modifications and equivalents as included within the spirit and scope of the invention as defined by the appended claims.
Referring to
The housing 12 is made of steel, plastic, or another suitable valve material depending on the application and environment for which the flow control valve 10 is used. In the illustrated embodiment, the housing 12 is generally cylindrical or barrel-shaped. Therefore, the flow control valve 10 is referred to as a barrel valve. Even so, in one embodiment the flow control valve 10 is a ball valve, a butterfly valve, or other well known style of valve. In such cases, the housing 12 has one of a variety of different shapes and configurations corresponding to the particular type of valve employed.
As shown in
Referring now to
In the illustrated embodiment, the flow control device 14 is represented as a cylinder having a radial channel 28 passing therethrough. Even so, the flow control device 14 is able to take other shapes or have other configurations depending on the type of the flow control valve 10 used as noted above. As shown, the flow control device 14 is rotatable about an axis generally perpendicular to a direction 30 of fluid flow. In contrast, the radial channel 28 is generally parallel to the direction 30 of fluid flow when the flow control valve 10 permits the full flow of fluid.
In the illustrated embodiment, the flow control device 14 is situated closer to the upstream end 22 of the housing 12. Therefore, a downstream portion 32 of the internal cavity 20 is left generally unoccupied by structural components. As will be discussed more fully below, when the flow control device 14 is rotated into the position shown in
Still referring to
For the purpose of illustration, the seal 34 employed in the illustrated embodiment of
The inlet 36 is configured to sealingly mate with the flow control device 14. In that regard, the inlet 36 in the illustrated embodiment includes a radially outwardly projecting inlet flange 46 that defines an inlet surface 48. To further encourage direct contact between the fluid directing device 14 (best seen in
As illustrated in
The outlet 38 is configured to sealingly mate with a portion of the housing 12 (e.g., the valve outlet 18). In the illustrated embodiment, and as best shown in
Still referring to
The convolution 42 generally gives the seal 34 the ability to both expand and contract. Whether the seal 34 expands or contracts depends, in part, upon the angle formed between the portions of the seal wall 56 that form the convolution. If the included angle is greater than ninety degrees, the length 52 of the seal 34 will increase if the pressure on the external surface 62 exceeds that upon the internal surface 60. The portions of the seal wall 56 forming the convolution 42 will be biased away from each other. In contrast, if the included angle is less than ninety degrees, the length 52 of the seal 34 will decrease if the pressure on the external surface 62 exceeds that upon the internal surface 60. The portions of the seal wall 56 forming the convolution 42 will be biased toward each other and, in some cases, may engage each other.
In the illustrated embodiment, when the inlet 36 and outlet 38 are drawn closer together and the seal 34 is compressed along its length 52, the convolution 42 simply projects further radially outwardly to accommodate the linear movement. In contrast, when the inlet 36 and outlet 38 move away from each other and the seal 34 is expanded along its length 52, the convolution 42 falls radially inwardly to accommodate the linear movement. If the seal 34 is expanded enough, the convolution 42 lies flat and/or generally parallel relative to adjacent portions 54 of the seal body 44. As those skilled in the art will recognize, the convolution 42 expands and contracts to permit the seal 34 to correspondingly expand and contract.
As shown in
In one embodiment, a portion of the seal 34 near the outlet 38 is fitted over a tapered end of the valve outlet 18. As such, the internal surface 62 mates with the tapered end of the valve outlet 18 and maintains an interference fit. This interference fit is able to encourage formation of a seal, even at low pressures. With an increasing differential pressure across the seal 34, the seal contracts radially inwardly against the valve outlet 18. In one embodiment, the seal 34 relies exclusively upon engagement between the internal surface 62 and the end of valve outlet 18 to form a seal and inhibit or prevent leakage. In such an embodiment, outlet surface 50 of the seal 34 need not maintain contact with the valve outlet 18 or the housing 12.
As those skilled in the art will recognize, the thickness 58 of the seal wall 34 affects the flexibility of the convolution 42, the strength of the seal 34, and the like. The thickness 58 of the seal wall 56 also contributes to the rate at which the seal 34 is able to expand and contract. In general, the thicker the seal wall 56, the slower the seal 34 responds to changing conditions such as, for example, a changing pressure differential across the seal wall 56.
In operation, the valve inlet 16 and valve outlet 18 of the flow control valve 10 are coupled to upstream and downstream pipe sections (not shown), respectively. The pipe sections are configured to transport a fluid such as, for example, water. Because the water is inclined to flow along the direction 30 of fluid flow (see
As the flow control device 14 is rotated by the actuator (not shown) such that the radial channel 28 is moved out of axial alignment with the valve outlet 18 (i.e., generally transverse to the direction 30 of fluid flow), some of the water that had been flowing through the flow control valve 10 is trapped within the downstream portion 32 of the internal cavity 20 and the flow of water through the flow control valve 10 is entirely halted. In this orientation, the flow control valve 10 is in a fully closed position.
Because it was forced into an enclosed space, the water seized or ensnared inside the downstream portion 32 is held under pressure. In contrast, the water in the valve outlet 18 is quickly carried away and allowed to escape the valve 10. As a result of the pressure on the external surface 60 being greater than the pressure on the internal surface 62, a pressure differential across the seal wall 56 is relatively large.
The large pressure differential across the seal wall 56 causes the flexible convolution 42 to move radially inwardly into the channel 40 and compels the seal body 44 to expand along its length 52 (
When the flow control device 14 is rotated by the actuator so that the radial channel is partially axially-aligned with the valve inlet 16 and valve outlet 18 as shown in
The second portion of water flows from the valve inlet 16, through the radial channel 28, and enters the downstream portion 32 of the internal cavity 20. Because the downstream portion 32 of the internal cavity 20 offers no outlet and is quickly filled, the pressure within the internal cavity 20 is elevated compared to the pressure within the valve outlet 18 where the water freely escapes from the flow control valve 10. As a result, the pressure on the external surface 60 of the seal wall 56 is higher than the pressure on the internal surface 62 and, once again, a pressure differential is created across the seal wall 56.
In the partially open position, while the pressure differential is not as great as when the flow control valve 10 is in the fully closed position, there still exists a pressure differential across the seal wall 56. The somewhat diminished pressure differential still causes the flexible convolution 42 to move somewhat radially inwardly into the channel 40 and compels the seal body 44 to expand somewhat along its length 52 (
When the flow control device 14 is moved from the partially aligned position of
If the flow control device 14 is rotated by the actuator such that the radial channel 28 is fully axially aligned with the valve inlet 16, the flow of water is permitted to freely flow through the flow control valve 10 and all of the water enters the radial channel 28. In such a case, the flow control valve 10 is in a fully opened position and the pressure differential across the seal wall 56 is small or negligible. Despite this slight pressure differential, the inlet surface 48 is still biased against the flow control device 14 and the outlet surface 50 is still biased against the housing 12 and/or valve outlet 18 due to the size, flexibility, elasticity, and/or other characteristics of the seal 34. In addition, because of the generally smooth, laminar flow of the water through the flow control valve 10, the stress on the seal 34 is, in many circumstances, minimal. Also, even if leakage occurs, this is acceptable since any leaking water will simply join the water that has been permitted to flow.
From the foregoing, those skilled in the art will recognize that the invention provides an elastomeric seal for a flow control valve (e.g., a barrel valve) that provides leak proof sealing, low operating torque (i.e., low friction), and lower cost compared to when springs, clamps, and/or o-rings are used. The seal performs these tasks by utilizing one or more convolutions to expand or contract the seal due to a pressure differential across a seal wall. As the pressure differential increases, the seal increasingly expands due to the convolution and promotes the formation of a sealing arrangement between adjacent parts.
All references, including publications, patent applications, and patents cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein.
The use of the terms “a” and “an” and “the” and similar referents in the context of describing the invention (especially in the context of the following claims) is to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms “comprising,” “having,” “including,” and “containing” are to be construed as open-ended terms (i.e., meaning “including, but not limited to,”) unless otherwise noted. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. 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 invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.
Preferred embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention. Variations of those preferred embodiments may become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventors expect skilled artisans to employ such variations as appropriate, and the inventors intend for the invention to be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context.
