WO2008079961A1

WO2008079961A1 - Valve

Info

Publication number: WO2008079961A1
Application number: PCT/US2007/088349
Authority: WO
Inventors: Paul G. Eidsmore
Original assignee: Swagelok Company
Priority date: 2006-12-22
Filing date: 2007-12-20
Publication date: 2008-07-03

Abstract

Embodiments of check valves that provide unbalanced loading or balancing of valve elements are disclosed. The unbalanced loading or biasing (10) may cause a valve element (D) to initially tilt when the valve transitions from a closed position to an open position. A valve element, a biasing or guide member, and/or a support member may be configured to produce the eccentric or unbalanced bias or load.

Description

VALVE

Related Application

[0001] The present application claims the benefit of U.S. provisional patent application serial number 60/871,545, filed on December 22, 2006, titled "Check Valve." U.S. provisional patent application serial number 60/871,545 is incorporated herein by reference in its entirety.

Background of the Disclosure

[0002] The present application relates to valves, such as, for example, a check valve. Examples of check valves are described in United States Patent Nos. 4,856,555 and 4,964,423 (referred to as "the '555 and '423 patents" herein), both issued to Gausman et al., the entire disclosures of which are fully incorporated herein by reference.

Summary of the Disclosure

[0003] In accordance with an aspect of the disclosure, eccentric or unbalanced loading or biasing of a valve element is utilized so that the valve element may initially tilt or move off axis just as the valve opens or just as the valve closes. In various embodiments, one or more of a valve element, a biasing or guide member, and/or a support member are configured to produce the eccentric or unbalanced bias or load.

Brief Description of the Drawings [0004] FIG. 1 is an exploded perspective view of a prior art check valve;

[0005] FIG. 2 is a longitudinal cross-sectional view of the valve of FIG. 1 in a closed position;

[0006] FIG. 3 is a longitudinal cross-sectional view of the valve of FIG. 1 in an open position;

[0007] FIG. 4 is an enlarged view of the encircled are of FIG. 2 illustrating interconnection of a seal member with a valve element;

[0008] FIG. 5 is a plan view of an exemplary embodiment of a biasing member having different length legs;

[0009] FIG. 5 A is a longitudinal cross-sectional view of a check valve that includes the biasing member shown in FIG. 5 in a closed position;

[0010] FIG. 5B is a longitudinal cross-sectional view of a check valve that includes the biasing member shown in FIG. 5 in an open position; [0011] FIG. 6A is a longitudinal cross-sectional view of a check valve having offset coil springs;

[0012] FIG. 6B is a longitudinal cross-sectional view of the valve of FIG. 6A in an open condition;

[0013] FIG. 7A is a longitudinal cross-sectional view of a check valve having coil springs of different sizes;

[0014] FIG. 7B is a longitudinal cross-sectional view of the valve of FIG. 7A in an open condition;

[0015] FIG. 8 is a plan view of an exemplary embodiment of a biasing member having an offset mounting portion;

[0016] FIG. 9 A is a plan view of an exemplary embodiment of a support member having an offset support portion;

[0017] FIG. 9B is a sectional view taken along the plane indicated by lines 9B-9B in Figure 9A;

[0018] FIG. 1OA is a longitudinal cross-sectional view of a check valve that includes the biasing member shown in FIG. 8 and the support member shown in FIG. 9 in a closed position; [0019] FIG. 1OB is a longitudinal cross-sectional view of a check valve that includes the biasing member shown in FIG. 8 and the support member shown in FIG. 9 in an open position;

[0020] FIG. 1 IA is a longitudinal cross-sectional view of a check valve that includes a tilted biasing member in a closed position;

[0021] FIG. HB is a longitudinal cross-sectional view of a check valve that includes in an open position;

[0022] FIG. HC is a side view of an exemplary embodiment of a support member having a tilted support portion;

[0023] FIG. 1 ID is a perspective view of the support member having a tilted support portion shown in FIG. HC;

[0024] FIG. 12A is a plan view of an exemplary embodiment of a valve element having a tilted engagement surface;

[0025] FIG. 12B is a sectional view taken along the plane indicated by lines 12B-12B in FIG. 12A;

[0026] FIG. 12C is a longitudinal cross-sectional view of a check valve that includes the valve element shown in FIGS. 12A and 12B in a closed position; [0027] FIG. 12D is a longitudinal cross-sectional view of a check valve that includes the valve element shown in FIGS. 12A and 12B in an open position;

[0028] FIG. 13 A is a plan view of an exemplary embodiment of a valve element having an offset engagement surface;

[0029] FIG. 13B is a sectional view taken along the plane indicated by lines 13B-13B in FIG. 13 A;

[0030] FIG. 13C is a longitudinal cross-sectional view of a check valve that includes the valve element shown in FIGS. 13A and 13B in a closed position; and

[0031] FIG. 13D is a longitudinal cross-sectional view of a check valve that includes the valve element shown in FIGS. 13A and 13B in an open position.

Description of the Exemplary Embodiments

[0032] Although the various embodiments are described herein with specific reference to valve designs similar to those shown in the '555 and '423 patents, such description is exemplary in nature and should not be construed in a limiting sense. The various inventive aspects, such as various alternatives of the valve element, guide or biasing member, and the support member, described herein may be used alone or in various combinations and sub- combinations with the check valve designs of the '555 and '423 patents and with other valve designs. [0033] While various inventive aspects, concepts and features of the inventions may be described and illustrated herein as embodied in combination in the exemplary embodiments, these various aspects, concepts and features may be used in many alternative embodiments, either individually or in various combinations and sub-combinations thereof. Unless expressly excluded herein all such combinations and sub-combinations are intended to be within the scope of the present inventions. Still further, while various alternative embodiments as to the various aspects, concepts and features of the inventions— such as alternative materials, structures, configurations, methods, circuits, devices and components, software, hardware, control logic, alternatives as to form, fit and function, and so on-may be described herein, such descriptions are not intended to be a complete or exhaustive list of available alternative embodiments, whether presently known or later developed. Those skilled in the art may readily adopt one or more of the inventive aspects, concepts or features into additional embodiments and uses within the scope of the present inventions even if such embodiments are not expressly disclosed herein. Additionally, even though some features, concepts or aspects of the inventions may be described herein as being a preferred arrangement or method, such description is not intended to suggest that such feature is required or necessary unless expressly so stated. Still further, exemplary or representative values and ranges may be included to assist in understanding the present disclosure, however, such values and ranges are not to be construed in a limiting sense and are intended to be critical values or ranges only if so expressly stated. Moreover, while various aspects, features and concepts may be expressly identified herein as being inventive or forming part of an invention, such identification is not intended to be exclusive, but rather there may be inventive aspects, concepts and features that are fully described herein without being expressly identified as such or as part of a specific invention, the inventions instead being set forth in the appended claims. Descriptions of exemplary methods or processes are not limited to inclusion of all steps as being required in all cases, nor is the order that the steps are presented to be construed as required or necessary unless expressly so stated.

[0034] FIGS. 1-4 herein are reproductions (with reference numbers not referred to herein removed and reference number "91" added) of FIGS. 1-4 of the '555 and '423 patents to illustrate an exemplary valve design. The check valve A includes a valve body B that defines a chamber C. Received in the chamber C are a valve element D, a support member E and a guide member or biasing member F. For example, the biasing member or biasing member F may be realized in the form of a linear guidance wafer (LGW) but other embodiments may be used. The valve element D may carry or be associated with a seal element 54 that makes and breaks contact with a radially extending facing seal surface of a recess 30 foπned in the valve body B. The biasing member F may be an annular wafer or disc that urges or biases the valve element to the closed position illustrated in FIG. 2. As best illustrated in FIG. 2, the biasing member of the '555 and '423 patents includes spiral shaped slots 90 that are angularly and evenly spaced apart approximately 120° about a central axis of the valve X. The slots 90 define fingers or legs 91 that act in a spring-like manner to apply a biasing force against the valve element D. By having the slots 90 angularly and evenly spaced apart, so as to provide uniformity of the legs 91, the guide member F provides a balanced biasing on the valve element D. This helps assure a linear movement of the valve element D between the open and closed positions. In the exemplary embodiments illustrated by Figures 1-4, the support member E provides an axial limit of the opening movement of the valve element D. In the embodiments of the valves of the '555 and '423 patents, the support member E includes openings 62 to provide flow through the support member E when the valve A is open. The biasing member F is supported between the support member E and the valve element D. The valve element D is coupled to an outer peripheral portion 84 of the biasing member F and the support member E has a raised central portion 66 that supports an inner radial or central portion 82 of the biasing member F in an exemplary embodiment. In the valves of the '555 and the '423 patents, the valve element D, the guide member F and the stop member E are coaxially aligned along the central axis X and balanced as illustrated.

[0035] In accordance with the present disclosure and inventive aspects thereof, in contrast to the embodiments of the '555 and '423 patents just described above, one or more of the valve element, guide or biasing member, and the stop or support member are modified to provide a unbalanced load or biasing force on the valve element. This unbalanced biasing results in an initial tilting of the valve element with respect to the central axis or centerline X of the valve when the cracking or opening pressure is reached in an exemplary embodiment. This tilting may also exist as the valve closes, especially at low operating pressures, as the valve element starts to contact the seal surface. The tendency of the biasing member to vibrate is dampened by the tilting effect because a portion of the valve element (and notably the associated seal) remains in contact with the seal surface initially before the valve element completely shifts away from the body. The tilting effect and unbalanced bias on the valve element helps reduce any tendency of the valve element to chatter or vibrate, akin to a harmonic or resonance effect, when the operating pressure is near the cracking pressure, in effect lowering the resonant pressure at which such vibration may be observed. This reduced resonant pressure may further then result in the use of a smaller biasing force of the guide member, therefore allowing a large space between the valve member and the valve body, thus increasing flow in the open position. [0036] In the various embodiments herein, alternative configurations of the valve element, biasing or guide member, and support or stop member may be used as substitutes for the configurations shown in the '555 and '423 patents, or alternatively may be incorporated into other check valve designs. The valve element, biasing or guide member, and/or support or stop member may take a wide variety of forms that differ from the forms shown in the '555 and '423 patent. For example, the valve element may be any element that engages a surface to inhibit or prevent the flow of fluid. The biasing or guide member may be disposed in the valve in any fashion that causes the biasing member to force the valve member toward the closed position, either directly or indirectly, including configurations where the support member is omitted. When support members are included, the stop portion may be omitted from the support member and the support member may not provide an axial limit on the opening movement valve element. Various alternatives of each of the components may be used together or in various combinations and sub-combinations.

[0037] Fig. 5 illustrates an embodiment of a guide or biasing member 10. The biasing member 10 may be similar in most respects to the guide member F described above and in the '555 and '423 patents. One difference between the biasing member 10 and the guide member F is that legs 13 of the biasing member 10 are configured to apply an unbalanced biasing force to a valve element D. (Figures 5 A and 5B). The legs 13 may be configured to provide an unbalanced biasing force to the valve element D in a wide variety of different ways. Examples the legs 13 that may provide an unbalanced biasing force include, but are not limited to, legs with different thicknesses with respect to one another, legs with different lengths with respect to one another, legs with stiffnesses that are different from one another, less that are spaced at different distances from a center X of the biasing member and/or legs that are spaced unevenly around the center X of the biasing member. Any arrangement of legs 13 that provides an unbalanced biasing force to the valve element may be employed.

[0038] In the exemplary embodiment illustrated by Figure 5, the legs 13 are formed by spiral slots 12a, 12b, 12c that are not angularly cut the same, hi the embodiment illustrated by Figure 5, a spiral slot 12a is cut through an arc of 220°, a spiral slot 12b is cut through an arc of 240°, and a spiral slot 12c is cut through an arc of 260°. However, the slots may be cut through any set of arcs, and any number of slots may be included. The arc values are exemplary and may be adjusted as needed. Note that in the exemplary embodiment illustrated by FIG. 5 the inner radial end 14 of the slot 12c is angularly offset 120° from the inner radial end 16 of the slot 12b and the inner radial end 18 of the slot 12a. Thus, the slots 12 have inner radial ends that may be but need not be evenly spaced angularly from each other, but because of the different arcuate lengths will present an unbalanced biasing against the valve element. The unbalanced bias may also be enhanced or controlled in different ways, for example, two of the three slots may have the same arcuate length, or the slots may have unevenly spaced inner radial ends, or the slots need not all be formed as similar spiral shapes. The different arcuate length slots may also be combined with an eccentric or off-center center portion 20 (see Fig. 8 herein). The number of slots may also be varied, being more or less than the three illustrated in the exemplary embodiments herein.

[0039] The biasing member 10 includes a central mounting portion 20. In the example illustrated by FIG. 5, the central mounting portion comprises a central opening 20. The opening 20 accepts a stop in the valve embodiment illustrated by Figures 5A and 5B. [0040] The use of three uneven slots 12 in the Fig. 5 embodiment produces three spring-like legs 13a, 13b and 13c that have different lengths. These different lengths cause the legs 13a, 13b, 13c to each exhibit a different harmonic response thus reducing and in some applications eliminating the tendency of the biasing member 10 as a whole to harmonically vibrate. Thus, any tendency of the biasing member 10 to vibrate is reduced not only by the dampening caused by the tilting effect (a portion of the valve element remaining in contact with the seal surface at initial cracking or opening of the valve) but also by the reduced tendency of the biasing member 10 to have a harmonic response. The use of legs having different harmonic responses may be combined with other exemplary embodiments herein.

[0041] Figures 5A and 5B illustrate a valve 500 that includes the biasing member 10. The valve 500 may be constructed in generally the same manner as the valve A shown in FIGS. 1-4. The biasing member 10 urges the valve element D to the closed position illustrated in FIG. 5A. The different length legs 13a, 13b, 13c provide an unbalanced biasing force on the valve element D. When fluid under pressure is applied to the valve element D in the direction indicated by arrow 502, the valve element will initially tilt as indicated by arrow 504. hi an exemplary embodiment, the tilting will occur as a result of flexing of the longest leg 13c before flexing of the two shorter legs 13a, 13b. If all other parameters are the same, the longest leg 13c will be most flexible and will flex first when pressure is applied to the valve element.

[0042] Referring to Figure 5B, if a stop portion 66 is included, the valve element D will abut the stop portion 66 of the support member E when the valve is fully open. The initial tilt is eliminated by abutment of valve element D against the stop portion 66. [0043] As another alternative embodiment, since the biasing member acts as a spring-like biasing member, the biasing effect on the valve element may alternatively be realized using coil springs between the stop member and the valve element. Unbalanced biasing may be realized, for example by using coils springs having different lengths or thicknesses for example, or being unevenly spaced about the center axis of the valve member. Any configuration of one or more coil springs that provides unbalanced biasing of the valve element can be employed. Using different coil springs may also be used to reduce the harmonic vibration otherwise possible if the coil springs are all the same.

[0044] Figures 6A and 6B illustrate an embodiment of a valve 600 that includes coil springs 602. One or more coil springs 602a are positioned closer to a centerline X of the valve element D than one or more other coil springs 602b. This arrangement provides unbalanced biasing of the valve element D. The coil springs may be the same size and have the same force and spring constants or the springs may have different sizes, different spring forces, and/or different spring constants.

[0045] Figures 7A and 7B illustrate an embodiment of a valve 700 that includes coil springs 702. One or more coil springs 702a has a spring force when the valve element D is in the closed position that is greater than the spring force of other coil spring(s) 702b when the valve element is in the closed position. This arrangement provides unbalanced biasing of the valve element D. The coil springs may have different spring constants. For example, the spring(s) 702b with the lower initial spring force may have a higher spring constant than the spring(s) 702(a) with the higher initial spring force. This arrangement will causes the difference between the forces applied by the springs to diminish as the valve element is moved to the open position. In other embodiments, the spring constants of the springs 702a, 702b may be the same, or the spring constant of the spring(s) 702(a) with the higher initial spring force may be higher than the spring constant of the springs 702(b) with the initially lower spring force.

[0046] With reference to Fig. 8, in another embodiment, a guide or biasing element 30 may be provided with evenly spaced and cut slots 32, as for example in the '555 and '423 patents, but in this case the mounting portion 34 may be eccentrically positioned, or in other words radially offset from the center axis 36 of the guide member 30. The mounting portion 34 for example may have a central axis 38. A radial distance 40 may be selected as needed between the axes 36 and 38 to provide an unbalanced biasing against the valve element. The mounting portion 34 of the biasing member may take a wide variety of different forms, any of which may be used in any of the embodiments disclosed herein. Examples of mounting portions of the biasing member include, but are not limited to, mechanical fastening arrangements, surfaces that facilitate welding, raised projections that cooperate with an opening of the valve body B or an optional support member, an opening that cooperates with a projection of the valve body B or an optional support member, and the like. Any mounting structure that facilitates offset operative coupling of the biasing member 30 to the valve body B can be used, hi the example illustrated by Figure 8, the mounting portion 34 comprises a circular opening.

[0047] With reference to Figs. 9A and 9B, in another embodiment, a support member 50 is configured to provide an unbalanced biasing to the valve element by providing an eccentric or off-center mounting portion 52. The mounting portion 52 may take a wide variety of different forms, any of which may be used in any of the embodiments disclosed herein. The biasing member may be attached to the mounting portion or the biasing member may be operatively coupled to the mounting portion without being attached to the mounting portion. Examples of mounting portions include, but are not limited to, mechanical fastening arrangements, surfaces that facilitate welding, raised projections that cooperate with an opening in the biasing element, openings that cooperate with a projection of the biasing element, and the like. Any mounting portion that facilitates operative coupling of the biasing element to the support member can be used. In the example illustrated by Figures 9A and 9B, the mounting portion 52 is a raised portion of the support member 50 that cooperates with an opening in the biasing member.

[0048] Figures 1OA and 1OB illustrate a valve 1000 that includes the biasing member 30 and the support member 50. The mounting portion 52 aligns with the off-center portion 34 of the biasing member 30 illustrated in Fig. 8, for example. Alternatively, the support member 50 may be used with a differently configured biasing member or the biasing member 30 may be used with a differently configured support member so as to apply an unbalanced biasing to the valve member. The valve 1000 may be constructed in generally the same manner as the valve shown in FIGS. 1-4. The biasing member 30 urges the valve element D to the closed position illustrated by FIG 1OA. The offset 1010 (Figure 10B) of the mounting portion 34 of the biasing member 30 and the mounting portion 52 of the support member 50 with respect to the valve element D provide an unbalanced biasing force on the valve element D. When fluid under pressure is applied to the valve element D in the direction indicated by arrow 1002, the valve element will initially tilt as indicated by arrow 1004. In an exemplary embodiment, the tilting will occur as a result of flexing of a first side 1011, where a distance between the mounting portion 52 and an edge 1012 of the biasing member 30 is greatest, before a second side 1013 of the biasing member flexes. FIG. 1OB illustrates the valve 1000 in a fully open condition. The support member 50 is provided with a plurality of passages 54 for fluid flow when the valve is in the open position.

[0049] In another embodiment, one or more engagement surfaces that are coupled to the valve element D or the valve body B are tilted to provide an unbalanced biasing force 13. FIGS. 1 IA and 1 IB illustrate an example of a valve 1100 with a biasing member 1102 with an engagement surface 1103 that is tilted to provide an unbalanced biasing force. The engagement surface 1103 that is operatively coupled to the valve body B and/or an engagement surface 1104 that is operatively coupled to the valve element D can be tilted in a wide variety of different ways. Examples of ways the engagement surfaces 1103, 1104 of the biasing member 1102 can be tilted include, but are not limited to, providing axially offset surfaces on the valve body, the support member, and/or the valve element that engage the engagement surface of the biasing member and/or providing one or more inclined surfaces on the valve body, a support member, and/or a valve element that engage the engagement surface of the biasing member. Any manner of tilting an engagement surface 1103, 1104 of the biasing member such that the biasing member provides an unbalanced biasing force can be employed.

[0050] Figures 11C and 1 ID illustrate a support member 60 that includes a mounting portion 62 having a surface 64 that is tilted at an angle θ relative to a central axis 66 of the stop member 60 (where θ may be any value other than 0 or 90 degrees). The tilted surface 64 is the surface against which the engagement surface 1103 of the biasing member 1102 is seated. The tilted surface 64 thus causes the biasing element 1102 to tilt and provide an unbalanced biasing against the valve element. Note that the support member 60 includes a plurality of passages 70 for flow when the valve is in the open position. [0051] The valve 1100 of FIGS. HA and HB may be constructed in generally the same manner as the valve A shown in FIGS. 1-4. The biasing member 1102 urges the valve element D to the closed position illustrated by Figure 1 IA. The tilting of the engagement surface 1103 of the biasing member 1102 causes the biasing member to provide an unbalanced biasing force on the valve element D. When fluid under pressure is applied to the valve element D in the direction indicated by arrow 1104, the valve element will initially tilt as indicated by arrow 1106. In an exemplary embodiment, the tilting will occur as a result of flexing of a first side 1110 of the valve element 1102. At the first side 1110, the engagement surface 1103 is further away from the valve element D. As such, the first side 11 10 is less compressed than a second side 1112 of the biasing member and less force is required to compress the first side 1110 than the second side 1112. FIG. 1 IB illustrates the valve 1100 in an open condition.

[0052] Figs. 12A and 12B illustrate a valve element 80 that is configured to cause an engagement surface 1104 of a biasing member 1102 (Figures 12C and 12D) to tilt, hi this example, the valve element 80 supports a seal 82 on one face. On an opposite face 84 (that faces the biasing member and support member), a recess 86 is provided that provides a tapered surface 88. Figures 12C and 12D illustrate a valve 1200 that includes the valve element 80. The tapered surface 88 supports the engagement surface 1104, which is the outer periphery of the biasing member in the illustrated embodiment, thus providing an unbalanced biasing against the valve member. This causes the engagement surface 81 of the valve member 80 to tilt.

[0053] The valve 1200 may be constructed in generally the same manner as the valve A shown in FIGS. 1-4. The biasing member 1102 urges the valve element 80 to the closed position as illustrated by HB. The tilting of the engagement surface 1104 of the biasing member 1102 causes the biasing member to provide an unbalanced biasing force on the valve element 80. When fluid under pressure is applied to the valve element 80 in the direction indicated by arrow 1202, the valve element will initially tilt as indicated by arrow 1204. hi an exemplary embodiment, the tilting will occur as a result of flexing of a first side 1210 of the biasing member. At the first side 1210, the engagement surface 1104 is further away from the valve element 80. As such, the first side 1210 is less compressed than a second side 1212 of the biasing member and less force is required to compress the first side 1210 than the second side 1212. Fig. 12D shows the valve 1200 in an open condition.

[0054] Figs. 13 A and 13B illustrate another embodiment of a valve element 90. The valve element 90 is configured to offset the biasing member F with respect to the valve element 90. The valve element 90 can be configured to offset the biasing element with respect to the valve element in a variety of different ways. For example, an engagement structure 92 of the valve element that operatively couples the valve element to the biasing member F may be offset from a centerline of the valve element. The engagement structure 92 may be any structure that connects or operatively couples the biasing member F to the valve element.

[0055] In the example illustrated by Figures 13A and 13B, the engagement structure comprises a radially offset recess 92 relative to the central axis 94 of the valve element (the central axis of the recess 92 represented as 98, radially off-set a distance 99 from the central axis 94). [0056] Figures 13C and 13D illustrate a valve 1300 that includes the valve element 90. The valve 1300 may include a biasing element 30 constructed generally in accordance with the embodiment shown in FIG. 8 and a support member 50 shown constructed generally in accordance with the embodiment shown in FIGS. 9 A and 9B. However, the valve element 90 may be used with other embodiments of those components and embodiments where the support member is omitted. For example, a biasing element that has a mounting structure that is located at the center of the biasing member (rather than being offset as in the embodiment shown in FIG. 8) may be used. For example, a smaller version of the biasing element disclosed by the '555 and '423 patents may be used. The off-set recess 92 supports the outer periphery of the biasing member so as to apply an unbalanced biasing to the valve element 90. A surface 96 is provided for attaching the seal element.

[0057] The valve 1300 may be constructed in generally the same manner as the valve A as shown in FIGS. 1-4. The biasing member F urges the valve element 90 to the closed position illustrated by FIG. 1OA. The offset of the mounting structure 66 for the biasing member F and the recess 92 of the valve element 90 provide an unbalanced biasing force on the valve element 90. When fluid under pressure is applied to the valve element 90 in the direction indicated by arrow 1302, the valve element will initially tilt as indicated by arrow 1304. Figure 13D illustrates the valve 1300 in a fully open condition.

[0058] The inventive aspects have been described with reference to the exemplary embodiments. Modifications and alterations will occur to others upon a reading and understanding of this specification. It is intended to include all such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.

Claims

1. A valve comprising: first and second body portions which define a valve chamber; an inlet and an outlet communicating with said valve chamber; a valve element received in said valve chamber for selective movement in response to pressure differentials; a support member received in said valve chamber; and a biasing member interposed between said valve element and said support member for unbalanced biasing of said valve element toward a closed position.

2. The valve of claim 1 wherein the biasing member includes legs having different lengths to produce said unbalanced biasing.

3. The valve of claim 2 wherein the different length legs each have different harmonic responses to reduce harmonic vibration of the biasing member as a whole.

4. The valve of claim 1 wherein the biasing member comprises one or more coil springs configured to produce said unbalanced biasing.

5. The valve of claim 1 wherein a portion of the biasing member that engages the support member is offset from a center of the biasing member.

6. The valve of claim 5 wherein the biasing member includes legs having equal length.

7. The valve of claim 5 wherein the biasing member includes legs having unequal lengths.

8. The valve of claim 1 wherein an engagement surface of the biasing member is tilted to produce said unbalanced biasing.

9. The valve of claim 1 wherein the biasing member engages a tilted surface of the support member to produce said unbalanced biasing.

10. The valve of claim 8 wherein the biasing member includes legs having equal length.

11. The valve of claim 8 wherein the biasing member includes legs having unequal lengths.

12. The valve of claim 1 wherein a first portion of the biasing member engages a first surface of the support member and a second portion of the biasing member engages a second surface of the support member and wherein the first and second surfaces of the support member are offset along a central axis of the support member.

13. The valve of claim 1 wherein the biasing member engages a tilted surface of the valve element to produce said unbalanced biasing.

14. The valve of claim 1 wherein a first portion of the biasing member engages a first surface of the element and a second portion of the biasing member engages a second surface of the valve element and wherein the first and second surfaces of the valve element are offset along a central axis of the support member.

15. The valve of claim 1 wherein a center line of the biasing member is offset from a centerline of the valve element to produce said unbalanced biasing.

16. The valve of claim 15 wherein the biasing member includes legs having equal length.

17. The valve of claim 15 wherein the biasing member includes legs having unequal lengths.

18. The valve of claim 1 wherein the biasing member is detached from said first and second body portions.

19. The valve of claim 1 wherein a radially inner portion of said biasing member is operatively associated with a radially inner portion of said support member and a radially outer portion of said biasing member is operatively associated with a radially outer portion of said valve element.

20. The valve of claim 1 wherein the support member includes a stop portion for limiting opening movement of said valve element.

21. A check valve comprising: first and second body portions which define a valve chamber; an inlet and an outlet communicating with said valve chamber; a valve element received in said valve chamber for selective movement in response to pressure differentials; a support member received in said valve chamber; and means for unbalanced biasing of said valve element toward a closed position.

22. A check valve comprising: a valve chamber; an inlet and an outlet communicating with said valve chamber; a valve element received in said valve chamber for selective movement in response to pressure; and a biasing member with spring legs having different lengths that provides unbalanced biasing of said valve element toward a closed position.

23. The check valve of claim 22 wherein the different length legs each have different harmonic responses to reduce harmonic vibration of the biasing member as a whole.

24. A check valve comprising: first and second body portions which define a valve chamber; an inlet and an outlet communicating with said valve chamber; a valve element received in said valve chamber for selective movement in response to pressure differentials; and one or more coil springs configured to provide unbalanced biasing of said valve element toward a closed position.

25. A check valve comprising: first and second body portions which define a valve chamber; an inlet and an outlet communicating with said valve chamber; a valve element received in said valve chamber for selective movement in response to pressure differentials; and a biasing member that engages the valve element at a location that is offset from a center line of the valve element to cause unbalanced biasing of said valve element toward a closed position.

26. A check valve comprising: first and second body portions which define a valve chamber; an inlet and an outlet communicating with said valve chamber; a valve element received in said valve chamber for selective movement in response to pressure differentials; and a biasing member that is tilted to provide an unbalanced biasing of said valve element toward a closed position.

27. The check valve of claim 26 wherein the biasing member engages a tilted surface of a support member disposed in said valve chamber to produce said unbalanced biasing.

28. The check valve of claim 26 wherein the biasing member engages a tilted surface of the valve element to produce said unbalanced biasing.

29. A method of inhibiting fluid flow in a first direction along a path of travel and allowing fluid flow in a second direction along the path of travel comprising: inhibiting fluid flow in said first direction by applying an unbalanced biasing force to a valve element with a biasing member with spring legs having different lengths; applying fluid in said second direction to flex said spring legs to thereby allow fluid flow in said second direction.

30. A method of inhibiting fluid flow in a first direction along a path of travel and allowing fluid flow in a second direction along the path of travel comprising: inhibiting fluid flow in said first direction by applying an unbalanced biasing force to a valve element with one or more coils springs; applying fluid in said second direction to flex said one or more coil springs to thereby allow fluid flow in said second direction.

31. A method of inhibiting fluid flow in a first direction along a path of travel and allowing fluid flow in a second direction along the path of travel comprising: inhibiting fluid flow in said first direction by applying an unbalanced biasing force to a valve element with a biasing member that engages the valve element at a location that is offset from a center line of the valve element; and applying fluid in said second direction to flex said biasing member to thereby allow fluid flow in said second direction.

32. A method of inhibiting fluid flow in a first direction along a path of travel and allowing fluid flow in a second direction along the path of travel comprising: inhibiting fluid flow in said first direction by applying an unbalanced biasing force to a valve element with a tilted spring; applying fluid in said second direction to flex said tilted spring to thereby allow fluid flow in said second direction.