The present invention relates to valves, and more particularly, to bidirectional valves which bias fluid flow in one direction relative to another.
Bidirectional valves used to bias fluid flow in one direction relative to another typically utilize multiple moving parts (e.g., a translatable piston) to change the volume of a given flow path, and thus the pressure and resistance to fluid flow associated with the given flow path. In such applications, frictional bias and momentum of the fluid flow through the given flow path can resist changes in movement (e.g., translation) of the piston, resulting in hysteresis of the valve over time, as well as undesired flow patterns and valve configurations. Additionally, such bidirectional valves typically require tight manufacturing tolerances to function properly. Changes in entrance edge conditions to pathways in the valve caused by manufacturing processes can cause unwanted variation in flow-field behavior and flow rate. For example, deburring processes and tooling limitations in applications which require tight tolerances can impact geometries of leading edges of passages extending through the valve, especially when drilled at an angle relative to a flat surface, or through convex or concave surfaces.
Such conventional methods and systems have generally been considered satisfactory for their intended purpose. However, there is still a need in the art for a systems and methods that allow for easier and more efficient manufacturing, installation, and operation of bidirectional valves.
A valve for regulating bidirectional fluid flow is provided. The valve includes a first flow body defining a passage therethrough having an inlet, an opposed outlet, and a bore fluidly coupling the inlet and outlet. The passage of the first flow body is configured to direct fluid flow in a downstream direction defined from the inlet to the outlet. The inlet includes an enlargement configured to provide decreased resistance to fluid flow in the downstream direction relative to flow in an upstream direction opposite the downstream direction.
In certain embodiments, a second flow body is operatively associated with the first flow body. The first and second flow bodies together define a chamber therebetween in fluid communication with the inlet of the first flow body. The second flow body can define a passage for bidirectional fluid flow therethrough with an inlet on one side thereof and an outlet on an opposite side thereof leading to the chamber. The inlet of the second flow body can include an enlargement configured to bias fluid flow therethrough in the downstream direction toward the chamber and first flow body relative to flow in the upstream direction. The passages of the first and second flow bodies can also define respective axes offset from one another in order to promote bias in fluid flow in the downstream direction.
In certain embodiments, a third flow body, like the first and second flow bodies described above, is operatively associated with the second flow body. The second and third flow bodies together define an additional chamber therebetween in fluid communication with the inlet of the second flow body.
In accordance with certain embodiments, the first, second, and third flow bodies are static and are mounted to one another in a stacked configuration. In such embodiments, the volumes of the chambers between flow bodies can remain constant.
In certain embodiments, the second flow body is disposed radially outward of the first flow body such that the passage of the first flow body directs fluid bidirectionally in a radially downstream direction defined from the inlet to the outlet, and in a radially upstream direction opposite the downstream direction. In such embodiments, the first and second flow bodies can define an annular damping chamber therebetween in fluid communication with the inlet of the first flow body, whereby downstream fluid flow is radially inward, and upstream fluid flow is radially outward. The inlet of the first flow body can include an enlargement configured to provide decreased resistance to fluid flow in the radially downstream direction relative to the radially upstream direction. The first and second flow bodies can be translatable relative to one another to increase size of the annular chamber during radially upstream fluid flow, and to decrease size of the annular chamber during radially downstream fluid flow. The flow bodies can be configured to form sealed bearings on opposite sides of the annular chamber, and to provide increased damping of fluid flow in the upstream direction relative to the downstream direction.
In accordance with certain embodiments, the first flow body can define a plurality of additional radially extending passages fluidly coupled to the annular damping chamber, longitudinally offset from one another, and configured to provide decreased resistance to fluid flow in the radially downstream direction relative to the radially upstream direction. The flow bodies can be configured such that translation relative to one another blocks at least one radially extending passage defined in the first flow body to increase resistance to fluid flow in the radially upstream direction.
These and other features of the systems and methods of the subject invention will become more readily apparent to those skilled in the art from the following detailed description of the preferred embodiments taken in conjunction with the drawings.
So that those skilled in the art to which the subject invention appertains will readily understand how to make and use the devices and methods of the subject invention without undue experimentation, preferred embodiments thereof will be described in detail herein below with reference to certain figures, wherein:
Reference will now be made to the drawings, wherein like reference numerals identify similar structural features or aspects of the subject invention. For purposes of explanation and illustration, and not limitation, a partial view of an exemplary embodiment of a valve for regulating bidirectional fluid flow in accordance with the invention is shown in
The valve 10 includes a first flow body 12 defining a plurality of passages 14 therethrough. Each passage 14 has a respective inlet 16, an opposed outlet 18, and a bore 20 fluidly coupling inlet 16 and outlet 18. Each passage 14 of first flow body 12 is configured to direct fluid flow in a downstream direction from inlet 16 to outlet 18, with an opposed upstream direction defined from outlet 18 to inlet 16. Inlet 16 includes an enlargement 22 configured to provide decreased resistance to fluid flow in the downstream direction relative to the upstream direction. The enlargements 22 facilitate fluid entry into the passages 14 by defining wider openings which catch and direct downstream fluid flow therethrough. By contrast, the outlets 18 define smaller openings, and thus are less able to facilitate upstream fluid entry into the passages 14 compared to the inlets 16, especially when fluid is moving at an angle relative to the axes of passages 14. The enlargements can be configured to reduce entrance edge conditions imparted on the fluid flow, which also biases fluid entry into the passages 14 in the downstream direction as further discussed below.
Referring now to
Fluid exiting outlets 18 of the second flow body 24 must change direction upon exiting flow body 24 in order to reach inlets 16 of the first flow body 12, and may additionally strike opposing wall 13 of the first flow body 12 prior to reaching inlets 16. This offsetting of the passages 14, 30 therefore enhances the bias in fluid flow in the downstream direction because when the fluid changes direction, it must enter opposing inlets at an angle, and the effect of the enlarged inlets to facilitate fluid transfer in the downstream direction therethrough is even further enhanced. It will be appreciated that such offsetting can be done vertically, horizontally, radially, or in any other suitable direction or combination of directions. Additionally, it will be appreciated that variations in diameter and length of the passages 14 and the axial length of the chamber 28 can further influence biasing of the fluid flow downstream as needed for specific applications.
Second and third flow bodies 24, 26 define an additional chamber 38 therebetween in fluid communication with inlets (hidden) of second flow body 24. Third flow body 26 may be constructed similarly to first flow body 12, and is mounted to second flow body 24 in the same manner as second flow body 24 is mounted first flow body 12. It will be appreciated that first, second, and third flow bodies 12, 24, 26, as well as chamber 28 and chamber 38 are static (e.g., they do not move relative to one another and do not change in size, shape, or orientation relative to one another), yet work together to bias fluid flow in the downstream direction. As shown, the second flow body 24 is rotated relative to the first and third flow bodies 12, 26 such that the respective passages 14, 30, 40 of the flow bodies 12, 24, 26 are offset circumferentially relative to one another. Such offsetting can be done in any other suitable manner as discussed above.
It is anticipated that bidirectional valve 10 can be used, for example, for fuel circuit control on a fuel nozzle for a gas turbine engine. If fluid is travelling downstream, the discharge coefficient (CD) may be around 0.85 for each drilled passage 14 due to improved entrance effects at inlets 16. However, if the flow is reversed (e.g., upstream from outlet 14 to inlet 16, the discharge coefficient may be reduced to around 0.70, which corresponds to a restriction of approximately 20% to reverse flow.
Stacking of the valves 10 as shown in
With reference now to
For example, various types of enlargements (e.g., such as those shown in
The chamfer 111 is formed along a chamfer axis 113 into an inlet surface 112, and thus eliminates the sharp edge 105 of the angled bore 104. The chamfer 111 and bore 104 can be formed in any order, but the chamfer 111 will generally be formed after the bore 104 is formed. The chamfer 111 may be formed such that the chamfer angle 115 (relative to the normal of the inlet surface 112 of the flow body) is different than the bore angle 119. As shown, the chamfer angle 115 is less than the bore angle 119. In this case, the chamfer angle 115 is such that the relative angle 118 between the chamfer axis 113 and the bore axis 116 is about forty degrees, though other chamfer angles may be utilized. The chamfer 111 preferably has a depth 107 equal to or larger than about 15% of the diameter 109 of the bore 104, which renders it of sufficient size to substantially eliminate flow variation from bore to bore. The chamfer edge depth 120 is the depth of the edge-break on the acute-angle location of the entrance edge. The chamfer depth 107 is measured from the very tip of the chamfer bit to the inlet surface 112, along the chamfer axis 113. The chamfer edge depth 120 is measured from the inlet surface 112 along a normal thereto. The chamfer depth 107 and offset 117 are preferably adjusted such that the acute angled edge 105 of the original bore 104 is cut to a chamfer edge depth 120 of about 15% of the downstream bore diameter 109. If the bore angle 119 is 0°, then the chamfer angle 115 can be aligned with the bore angle 119. A chamfer edge depth 120 less than 15% may also be utilized, especially where surface geometry does not allow for depths larger than 15% on account of close proximity of entrance edges of multiple bores.
The discharge coefficient of fluid in a cylindrical bore varies less significantly once the depth of the chamfer exceeds 15% of the bore diameter downstream of the chamfer. For example, using a 0.031 inch diameter bore, increase in discharge coefficient of a fluid in the cylindrical bore varies minimally with increase in chamfer depth once the chamfer depth is over 0.005 inches.
Continuing with
With reference now to
The countersink 211 may be formed using a ball-nose endmill as shown. The countersink 211 can extend along a countersink axis 213 which is angled relative to the inlet surface 212, and substantially collinear with a longitudinal axis 216 of the bore 204. The endmill can alternatively be oriented at a different angle than the angle 215 of the downstream bore 204 to produce a countersink axis 213 oriented similar to chamfer axis 113 of
For example, for a 0° bore angle 215, the countersink depth 207 can be about 15% of the downstream bore diameter 209. If the bore angle 215 is 60°, the countersink depth 207 can be about 100% of the downstream bore diameter 217. The countersink depth 207 is preferably sufficient to cut the acute angle edge (shown in phantom) of the original bore 204 by the ball-nose endmill to provide improved flow. The countersink 211 is preferably of sufficient diameter and depth to yield an effect similar to the chamfer described above, and effectively creates an aerodynamic chamfer. The countersink 211 can alternatively be formed using a flat end-mill, a drill, or any other suitable boring device.
With reference now to
It has been determined that a ball-nose end-mill, as opposed to a drill-point, yields a higher flow-rate and reduced flow sensitivity for a given end-mill size. Ball-nosed end-mills of diameter about 30%-75% greater than that of the bore or passage can be used to increase the discharge coefficient by about 13%-23%. It has also been determined that a diameter ratio (ratio of end-mill diameter to bore diameter) of 1.6 yields better results than a diameter ratio of 1.3, and that a ball-nose end-mill with a 1.6 diameter ratio has a very low sensitivity to entrance-edge condition of the countersink. Similarly, drills of diameter of about 30%-75% greater than that of the bore can be used to increase the discharge coefficient by about 13%-20%.
It will be appreciated that by including some form of enlargement (e.g., chamfer or counter-sink) at the lead-in (e.g., the inlet surface), the variability in flow from bore to bore is greatly reduced, and has been found to be less than about 5%, largely due to variations in edge-breaks leading into the counter-bores.
While described above in the exemplary context of circular geometry, those skilled in the art will readily appreciate that non-circular geometries can also be used without departing from the scope of the invention. In the case of a non-circular bore, the desired depth of a particular enlargement will also be proportional to and correspond to the square root of a cross-sectional area of the bore downstream of the enlargement.
It will be appreciated that the above described enlargements are exemplary only, and that any type of enlargement of any shape and size can be utilized in accordance with the present invention (e.g., with respect to the embodiments of
With reference now to
The first flow body 412 is configured as a piston which is longitudinally translatable relative to the second flow body 424 to increase and decrease the size of the annular damping chamber 428. When the first flow body 412 is in the position of
The flow bodies 412 and 424 are configured to form a sealed bearing 409 adjacent annular chamber 428. In particular, edges (e.g., opposed match grind surfaces 413 and 415) of the flow bodies 412 and 424 allow a miniscule amount of fluid to flow therethrough for relatively sealed translation of the flow bodies 412 and 424 relative to one another. It will be appreciated that the flow rate allowed by the annular damping chamber in the upstream and downstream directions will act as a damper to the forces provided by the spring 430 and longitudinal fluid flow driving the piston. Additionally, the rate at which the damping chamber 428 expands will be slower than the rate at which it closes because of the directional bias of the passage 414.
In certain embodiments, the first flow body can define a plurality of additional radially extending passages 460 which are intermittently fluidly coupled to the annular damping chamber 428, and longitudinally offset from passage 414. Passages 460 become fluidly isolated from the damping chamber 428 when flow body 412 is in the position shown in
While the apparatus and methods of the subject invention have been shown and described with reference to preferred embodiments, those skilled in the art will readily appreciate that changes and/or modifications may be made thereto without departing from the spirit and scope of the subject invention. For example, while particular shapes, sizes, dimensions, proportions, and orientations of bore holes, passages, chamfers, countersinks, and flow bodies have been disclosed, it will be appreciated that other shapes, sizes, dimensions, proportions, and orientations may be utilized. It will also be appreciated that greater control and consistency of flow-field behavior and flow rate using the present invention may be achieved whether the fluid flow is gaseous, liquid, or both, and whether the application is for gas turbine fuel injectors or other technologies. Thus, it will be appreciated that changes may be made without departing from the spirit and scope of the invention as claimed.
Number | Date | Country | |
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Parent | 13872970 | Apr 2013 | US |
Child | 15790750 | US |