US20100154930A1

US20100154930A1 - Fuel flow shaper

Info

Publication number: US20100154930A1
Application number: US12/431,394
Authority: US
Inventors: Bryan William Clever
Original assignee: Delaware Capital Formation Inc
Current assignee: OPW Fueling Components LLC; Clove Park Insurance Co
Priority date: 2008-12-19
Filing date: 2009-04-28
Publication date: 2010-06-24
Also published as: US20100154923A1; EP2202196A1; US8215345B2

Abstract

A system including a flow shaper configured to be positioned in a spout such that fuel flowing through the spout passes through the flow shaper and exits in a fuel stream. The flow shaper includes an outer wall and a plurality of cavities formed therein, each cavity having a L/D ratio. An average L/D ratio of the cavities, weighted by cross sectional area, is at least about 8:1.

Description

This application claims priority to, and is a continuation-in-part of, U.S. application Ser. No. 12/339,940 filed on Dec. 19, 2008, the entire contents of which are hereby incorporated by reference.
The present invention is directed to a device for aligning fluid flow, and more particularly, a device for aligning the flow of fuel through a nozzle.

BACKGROUND

Fuel dispensers are widely utilized to dispense fuels, such as gasoline, diesel or other petroleum products, biofuels, blended fuels or the like, into the fuel tank of a vehicle or into other vessels. Many fueling nozzles include obstructions in the flow path that induce turbulence, vortices, and other turbulent eddy flows. For example, internal passages in the nozzle body, the interface between the nozzle body and the spout, and components in the spout such as an attitude device, sensing tube and sensing tube fitting may present obstructions. Even when the nozzle body lacks significant obstructions, the fuel flow may include turbulence, vortices, and other turbulent eddy flows due to the introduction of the fuel flow into the nozzle body, or due to other upstream conditions. Regulatory recommendations and industry standards limit the length of the spout, and therefore the fuel is typically unable to dissipate turbulence and reach a uniform flow pattern prior to exiting the spout.
The turbulent flow of fuel exiting the nozzle can present various difficulties. For example, many nozzles utilize an automatic shut-off device which includes a sensing port positioned near the end of the spout. A poor spray pattern of fuel exiting the nozzle can cause splash back of the fuel from the walls of the vehicle fill pipe. The splash back can reach the sensing port of the shut-off device, thereby causing nuisance shut offs. Exiting fuel may also wick upwardly along the underside of the spout, which can also cause nuisance shut offs.
Turbulent flow and/or poor spray patterns of fuel exiting the nozzle can also affect the performance of the system when refueling vehicles which include an onboard refueling vapor recovery (“ORVR”) system. In particular, liquid seal ORVR systems are typically designed such that the vehicle fill pipe has a progressively reduced inner diameter. This configuration is provided so that fuel flowing into the fill pipe can cover or extend continuously across the cross section of the fill pipe, during refueling, to form a liquid seal which prevents fuel vapor from escaping through the fill pipe. The reduction in diameter of the fill pipe also causes a vacuum to be generated during refueling due to the venturi effect of the entering fuel stream.
Many fuel dispensers are configured to capture vapors emitted from a vehicle fuel tank during refueling, and return the vapors to the underground fuel storage tank. For example, stage II vacuum assist vapor recovery systems utilize a vapor pump to capture vapor and return the captured vapor through a vapor path of the fuel dispenser back to the ullage space of the underground fuel storage tank. Stage II vacuum assist vapor recovery systems may be configured to detect an ORVR-equipped vehicle, and cease operation of the vapor pump upon detection of an ORVR-equipped vehicle (i.e., if a vacuum is detected at the point of refueling, or at the end of the nozzle).
However, if fuel flow exiting the nozzle has sufficient turbulence and/or an undesirable spray pattern, the flow stream may jet toward the narrowed neck of an ORVR fill pipe in a non-uniform manner. In this case, the fuel may fail to extend continuously across the cross section of the fill pipe, which can cause the vehicle ORVR system to fail to generate a sufficient vacuum at the point of refueling. The fuel dispenser may thus fail to identify an ORVR-equipped vehicle as such. In this case, the vacuum pump of the fuel dispenser may continue to operate, which causes fresh air to be draw into the ullage space of the underground fuel storage tank. This fresh air causes excessive evaporation of the volatile fuels in the storage tank, which can cause pollutants to be released into the atmosphere by venting.

SUMMARY

In one embodiment the invention is a nozzle system in which turbulence of the exiting fuel stream is reduced and improved spray patterns are provided. In particular, in one embodiment, the invention is a system including a flow shaper configured to be positioned in a spout such that fuel flowing through the spout passes through the flow shaper and exits in a fuel stream. The flow shaper includes an outer wall and a plurality of cavities formed therein, each cavity having a L/D ratio. An average L/D ratio of the cavities, weighted by cross sectional area, is at least about 8:1.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a front perspective view of a nozzle;

FIG. 2 is a side cross section of the spout of the nozzle of FIG. 1;

FIG. 3 is a front perspective view of the spout of FIG. 2;

FIG. 4 is a detail view of the area indicated in FIG. 2;

FIG. 5A is a side cross section of the flow shaper of FIGS. 2 and 4;

FIG. 5B is an end view of the flow shaper of FIG. 5A;

FIG. 5C is a front perspective view of the flow shaper of FIG. 5A;

FIG. 5D is a rear perspective view of the flow shaper of FIG. 5A;

FIG. 6A is an end view of the tube insert of FIGS. 2 and 4;

FIG. 6B is a side cross section of the tube insert of FIG. 6A;

FIG. 6C is a front perspective view of the tube insert of FIG. 6A;

FIG. 7 is an end view of another embodiment of the flow shaper;

FIG. 8A is an end view of another embodiment of the flow shaper;

FIG. 8B is a side cross section of the flow shaper of FIG. 8A;

FIG. 8C is a rear perspective view of the flow shaper of FIG. 8A;

FIG. 8D is a front perspective view of the flow shaper of FIG. 8A;

FIG. 9 is an end view of another embodiment of the flow shaper;

FIG. 10 is an end view of another embodiment of the flow shaper;

FIG. 11 is an end view of another embodiment of the flow shaper;

FIG. 12 is an end view of another embodiment of the flow shaper;

FIG. 13 is an end view of another embodiment of the flow shaper;

FIG. 14 is an end view of another embodiment of the flow shaper; and

FIG. 15 illustrates one embodiment of a velocity profile of fluid inside a chamber.

DETAILED DESCRIPTION

FIG. 1 illustrates a nozzle or dispenser body 10 configured to be inserted into the fill pipe of a vehicle fuel tank. Fuel is pumped from an underground fuel storage tank to the nozzle 10, through the spout 12 and into the fill pipe of the vehicle fuel tank. The nozzle 10 may include an optional vapor boot or bellows 14 which surrounds at least an upper end of the spout 12 to aid in vapor recovery. The nozzle 10 includes a lever 16 coupled to a main vapor valve and a main fuel valve (not shown) such that when the lever 16 is gripped and pivoted upwardly, the main valves are correspondingly opened, thereby allowing the flow of fuel and vapor through fuel and vapor paths of the nozzle 10, respectively.
As shown in FIG. 2, fuel which enter the nozzle 10/spout 12 flows past a check valve 18, along the length of the spout 12 and passes through a flow shaper 20 positioned at or near the distal end of the spout 12. The spout 12 may have a shut-off opening or sensing port 22 formed therethrough. In the illustrated embodiment, the sensing port 22 is positioned on an underside of the spout 12, near the tip 24 of the spout 12. The sensing port 22 is in fluid communication with a tube 26 via a tube fitting 28, as will be described in greater detail below.
The tube 26 is positioned in the spout 12, and an upstream end of the tube 26 is fluidly coupled to a shut-off device or circuit (not shown) which compares the pressure in the sensing port 22 to the dynamic pressure generated by a venturi effect of flowing fuel in the nozzle 10. When the differential pressure becomes sufficiently great, the shut-off circuit causes a shut-off mechanism to release the lever 16 and close the main fuel and main vapor valves, thereby interrupting the fueling process. For example, when the sensing port 22 is blocked or closed (i.e., temporarily, due to foam or splash back of liquid fuel) the vacuum levels in the shut-off circuit significantly increase, thereby triggering the automatic shut-off mechanism.
Accordingly, as noted above, splash back of fuel during the refueling process can land on the sensing port 22, thereby triggering shut off before the vehicle fuel tank is full. These nuisance or premature shut offs require the customer/operator to re-engage the nozzle 10 and lever 16, thereby adding wear and tear on the refueling components, and causing aggravation to the customer/operator.
The flow shapers 20 disclosed herein can help to align and straighten the flow, remove turbulence, and ensure a relatively straight and consistent flow of fuel exiting the spout 12. As best shown in FIGS. 5A-5D, in a first embodiment the flow shaper 20 includes an outer wall 30 and an inner wall 32 which is entirely radially spaced away from the outer wall 30, and generally concentrically positioned with respect to the outer wall 30. In the illustrated embodiment, both the outer 30 and inner walls 32 are generally cylindrical. However, the outer wall 30 may take on various shapes as desired to conform to the inner surface of the spout 12, and the inner wall 32 can also take various shapes as desired.
The flow shaper 20 includes a plurality of generally flat vanes 34 extending generally radially between the outer 30 and inner 32 walls. In this manner, the flow shaper 20, and in particular, the inner wall 32, defines an inner cavity, chamber or channel 36. The outer wall 30, inner wall 32 and vanes 34 define a plurality of outer cavities, chambers or channels 38 that generally surround and/or extend generally radially around the inner cavity 36. In particular, the outer cavities 38 may surround and/or extend radially around at least a majority of the perimeter of the inner cavity 36 (i.e. at least about 270 degrees in the illustrated embodiment). Each cavity 36, 38 may have a generally uniform shape/cross section, and lack any significant obstructions therein.
During fuel dispensing, fluid flowing down the spout 12 enters the central cavity 36 and each outer cavity 38. The upstream surface of the walls 30, 32 and vanes 34 physically redirect the fuel flow into the cavities 36, 38, thereby dividing the flow into a plurality of discrete streams.
As will be described in greater detail below, various arrangements of wall, vanes, etc. may be provided to form cavities, chambers, or channels which divide the fluid flow, and receive the fluid flow therethrough. Each of the cavities may have a L/D ratio, which represents a ratio of the length of the cavity to its hydraulic or effective diameter. The hydraulic diameter of each cavity represents the diameter of a tubular/cylindrical component with a circular cross section which provides the equivalent surface area/drag as that particular non-cylindrical cavity.
The L/D ratio for each of the cavities may be selected to ensure that fuel flow exiting from that cavity is fully developed, or nearly fully developed. Although the L/D ratio can vary depending upon the type of fluid, flow conditions and the like, classical fluid dynamic equations and experimentation has shown in normal operating conditions (i.e., in one case, for gasoline with a temperature range of 0° F. to 120° F.), for incompressible fluids and liquid fuels, a L/D ratio of at least about 10:1, is sufficient to provide fully developed flow for a particular cavity. This ratio does not depend upon the velocity of the fuel flow, but assumes that fluid flow fills the cross sectional area of each cavity (i.e. throughout the flow domain) to be able to become fully developed.
The L/D ratio required to provide fully developed flow may depend upon the viscosity of the fluid, which can vary for different types of fuel, varying temperatures, etc. For example, for use with ethanol, a L/D ratio of at least about 5:1 may suffice. However, at least a 10:1 ratio, or at least a 8:1 ratio, or at least a 5:1 ratio has been found to be sufficient for a wide variety of fuels under various conditions.
As flow first enters a cavity, frictional forces from the walls of the cavity are applied only to outermost portions of that fluid stream, adjacent to the walls. For a 10:1 L/D ratio scenario, by the time fluid has traveled ten times the hydraulic or effective diameter of the cavity, the frictional forces imparted by the walls of the cavity are generally sufficient to reach the center, or all, of the fluid in that cavity. In this case, the walls have exerted frictional forces upon all fluid exiting that cavity and provide a fully developed flow, or nearly fully developed flow, thereby increasing stability and reducing turbulence of the flow. Thus, the surface area of the walls of the cavities produce sufficient pressure drop, as the fluid passes therethrough, to cause tumbling and rotary vortices elements of the flow to become reduced or eliminated. In other words, fully developed flow may have a generally uniform (i.e., stable) velocity profile such that the velocity profile for fluid exiting the cavity is the same as a velocity profile for fluid just upstream of the exit location.
FIG. 15 illustrates the principles described above by showing the growth of a boundary layer 39 and various velocities profiles 41, 43, 45 along the length of a cavity. It should be understood that FIG. 15 is not necessarily to scale and that the boundary layer 39 and velocity profiles 41, 43, 45 may have differing appearances, and change in differing manners, than that shown in FIG. 15. Fluid first entering a cavity may have a velocity profile as shown at position 41. As fluid moves downstream through the cavity, the boundary layer 39 grows radially inwardly. At position 43, the boundary layer 39 has grown and further influenced the velocity profile compared to position 41. Finally, at position 45, the boundary layer 39 has influenced all of the fluid in the cavity, and the velocity profile 45 is fully developed. The fully developed velocity profile 45 has a parabolic shape with the greatest velocity at the center of the cavity, smoothly reducing down to a velocity of zero at the outer edges of the cavity.
The cavities of the flow shaper 20 may be configured such that an average of the L/D ratio of the cavities meets a minimum value. This average may be a weighted average based upon the cross sectional area of the cavities. For example, in one case the weighted average L/D ratio for all of the cavities of the fluid flow shaper 20 may be at least about 10:1. In another embodiment, the weighted average of each of the cavities is at least about 8:1. It has been found that providing cavities having a weighed average L/D ratio of at least about 8:1 may provide fully developed flow, or nearly fully developed flow, that is sufficient to cause tumbling and rotary vortices elements of the flow to become reduced or sufficiently eliminated, thereby reducing or eliminating splash-back and reducing premature shut-offs during the refueling process.
Instead of, or in addition to, providing fluid flow that is fully developed, various cavities may instead provide flow that is nearly fully developed. In this case the velocity profile 47, as shown in FIG. 15, is generally shaped as a parabola, and matches the velocity profile 45 for fully developed flow by at least about 80% (i.e. no values from the curve 47 deviate from the curve 45 by more than about 20%). In other words, for nearly fully developed flow, it can be considered that the difference x between the curves 45, 47 is not more than 20% of the associated velocity value of the fully developed profile 45. Nearly fully developed flow can also be considered as a flow condition in which fluid exiting a cavity has a velocity that is within 10% of the velocity of fluid 1 mm upstream of the exit location. In this case the change in fluid velocity is relatively low and the fluid flow can be considered relatively stable.
Returning to the specific example of the fluid flow shaper 20 shown in FIGS. 5A-5D, it can be seen that fluid exiting each cavity 36, 38, and/or each outer cavity 38 may be fully developed or nearly fully developed flow. However, due to the increased effective diameter of the central cavity 36, in one embodiment fluid exiting the central cavity 36 may be less fully developed (and may have a lower velocity than the surrounding fluid). For example, in one embodiment the L/D ratio for outer cavities is about 10:1, and the L/D ratio for the central cavity 36 may be less than about 10:1, such as about 5:1. However, because the fluid exiting the outer cavities 38 generally surrounds and “encapsulates” the majority of the fluid exiting the central cavity 36 (i.e. at least about 270 degrees in the illustrated embodiment), a stable outer ring of fluid generally entraps the less developed coaxial inner core of fluid and significantly prevents any diverging fluid streams.
As the flow exits the spout 12, the individual streams from the cavities 36, 38 will eventually merge and become a coherent single stream, ultimately with a uniform velocity profile. Thus, the outer ring of fully-developed or nearly fully developed fluid ensures that the exiting stream, as a whole, has a stable, circular spray pattern with a very low angle of divergence and little turbulence.
The flow shaper 20 may be positioned close to the end 24 of the spout 12 (i.e. within at least about the distance of the diameter, or effective diameter, of the spout 12 from the end 24) so that the flow shaper 20 can influence the exiting flow in the desired manner. However, the fuel shaper 20 can be positioned at any position along the length of the spout 12. In particular, if the spout 12 includes a generally continuous inner surface and lacks significant obstructions, the fuel shaper 20 can be located significantly upstream of the distal end, and even at or adjacent to the inlet end of the spout 12.
The embodiment shown in FIGS. 5A-5D includes six outer cavities 38. However, the number of cavities 38 can be reduced, in which case it may be desired to increase if the length of the cavities 38/flow shaper 20. Correspondingly, the length of the cavities 38/flow shaper 20 can be reduced, in which case it may be desired to increase the number of cavities 38. Thus it can be seen that the number of outer cavities 38 does not govern performance, but instead the exposure of the flow to the drag forces of the walls of the cavities 38, which dissipates the turbulent energy, determines the performance of the flow shaper. The added pressure drop as fluid travels through the cavities 38 provides the energy needed to produce fully developed fluid flow, or nearly fully developed fluid flow. In one embodiment, the flow shaper 20 includes at least four cavities.
The shaper 20 of FIGS. 5A-5D may be configured such that all streams exiting the shaper 20 are fully developed or nearly fully developed. For example, the length of the shaper 20 may be increased, and/or the size of the central cavity 36 reduced, such that fluid exiting all cavities 36, 38 is fully developed or nearly fully developed. However, if only the outer part of the flow is fully or nearly fully developed, this may help to reduce pressure drop across the spout 12. In particular, if all of the fluid exiting the spout 12 were to be fully developed, this might in some cases generate a significant pressure drop across the spout 12. This pressure drop could render the spout 12 more prone to resisting automatic shut offs, since the fluid flow through the upstream venturi path will be slower, thereby generating a lower vacuum pressure. In this case, the measured vacuum pressure differential by the shut off circuit would be lowered, and the shut off mechanism would not have enough vacuum to disengage the lever 16.
In contrast, if the flow shaper 20 does not fully develop all of the fluid, but only the more critical outer streams, the pressure drop across the flow shaper 20 is reduced, thereby ensuring proper operation of the nozzle 10 and ensuring proper operation of automatic shut offs. The same advantages apply when all of the fluid is nearly fully developed, instead of fully developed. In addition, if the cavities include a L/D ratio that is too large, the fluid flow may create too large of a back pressure. Accordingly, in some cases the L/D ratio of any given cavity, or an average of the cavities, or a weighted average of the cavities, may be no larger than at least about 10:1, or no larger about 15:1 in another embodiment, or no larger than about 20:1 in yet another embodiment.
As best shown in FIGS. 5A and 5C, the upstream end 34 a of each vane 34 may be tapered such that fluid flowing down the spout 12 first engages the radially outer ends of the vanes 34 and gradually engages the inner radial edges of the vanes 34. This arrangement helps to reduce pressure in the fluid and pooling of fuel along the leading edges 34 a of the vanes 34, thereby reducing eddies and other instabilities in the flow.
With a stable stream exiting the nozzle 10, splash back of fuel onto the shut-off port 22 is reduced, thereby reducing premature and nuisance shut offs. The stable flow pattern provided by the flow shaper 20 (and other embodiments disclosed herein) also ensures that the cross section of an ORVR fill pipe of a vehicle being refueled is continuously covered to ensure proper operation of the ORVR system of the vehicle, which ensures, in turn, that the stage II recovery system of a refueling system (i.e., the vapor pump) is not operated improperly.
The flow shaper 20 can be made of a wide variety of materials, such nearly any fuel resistent material including, but not limited to, polymers such as acetal, DELRIN® resinous plastic material sold by E. I. du Pont de Nemours and Company of Wilmington, Del., metals such as aluminum, zinc, etc. The vanes 34 and/or walls 30, 32 may be relatively thin to reduce pressure drop and may be, for example, 0.020″ thick or smaller. As best shown in FIGS. 4 and 5A, the downstream end 34 b of each vane 34 may be spaced inwardly from the downstream end 40 of the shaper 20, and the downstream end 24 of the spout 12, so that the vanes 34 are recessed and protected from breakage during use of the nozzle 10.
As best shown in FIGS. 5B and 5D, in one embodiment, the flow shaper 20 (and other embodiments disclosed herein) does not include outer cavities 38 extending around the entire perimeter (i.e., extending 360°) around the inner cavity 36. Instead, in the illustrated embodiment, the flow shaper 20 has an axially-extending cavity 42 along its bottom edge, and a wedge or spacer 44 positioned between two (or more) adjacent outer cavities 38 (or positioned in a single cavity) at one end (the downstream end) thereof, adjacent to the cavity 42. In the illustrated embodiment (as best shown in FIGS. 5B and 5D), the spacer 44 is shaped as a generally triangular component (with a central opening 50) and extends about 90° around the outer perimeter of the shaper 20.
The spacer 44 helps to reduce the formation of a thin meniscus film on the underside of the spout 12. In particular, fluid from the adjacent outer cavities 38′ may be prone to “creep” downwardly toward each other along the outer perimeter of the shaper 20, as shown by arrows 46 of FIG. 5D. Should these “trickle” fuel streams occur in sufficient volume, in particular in a sufficient volume to reach each other (i.e., meet at the bottom of the shaper 20), the merged trickle fuel streams 46 may curl around the lip of the shaper 20 and rise, by capillary action or otherwise, upwardly toward the sensing port 22, as shown by arrow 48 of FIG. 5D and FIG. 4.
In addition, the trickle streams 46 can merge to form a small pool or puddle at the bottom of the spout 12/shaper 20. The puddle may grow by entrapping adjacent flowing fuel due to induced drag from the puddling liquid. In addition, to the extent that there is an existing pool/puddle of liquid fuel, the fluid flowing through the channels 38′ adjacent to the spacer 44 seeks to drag adjacent, pooling liquid along with it out the end of the spout 12. If fluid were to creep upwardly sufficiently, the meniscus film of fluid could reach the sensing port 22, thereby triggering an undesired automatic shut off of the nozzle 20.
However, the spacer 44 is designed to prevent such a deformation of a sufficient meniscus film. In particular, because the radially outer points of the spacer 44 are spaced apart (i.e., by about 90° in the illustrated embodiment), the spacer 44 provides significant distance between the adjacent outer cavities 38′. Thus, the spacing provided by the spacer 44 ensures that the trickle streams 46 of the cavities 38′ do not merge, or if they do, are of very low volume. By sufficiently spacing the outer cavities 38′, any induced drag from the adjacent fluid streams upon fluid at the bottom center of the spacer 44 is reduced. Moreover, because the fluid flowing adjacent to the spacer 44 passes through channels (i.e. channels 38′) having a relatively high L/D ratio, velocity of the fuel through those channels 38′ is increased, which causes fluid to jet out rapidly and decreases the chances of pooling.
Thus, the spacer 20 may be configured to space apart the adjacent outer cavities 38′, or their radially outer edges, by at least about 90°, or at least about 60° or a distance of at least about π/D4, or at least about π/D6 of the effective diameter of the flow shaper 20. The spacer 44 is, in one embodiment, radially aligned with the sensing port 22 to reduce or minimize the generation of a film that can creep axially upwardly toward the sensing port 22. The spacer 44 can be any of a wide variety of shapes or forms, other than triangular, so long as the spacer 44 provides sufficient spacing between the outer cavities 38′, and in particular, the radially outward ends of the cavities 38′. In this manner, the fuel may not be able to wick or curl around the edge of the spout 12 in sufficient volumes/velocity to reach the sensing port 22, and pooling and puddling of fuel at the bottom center of the spout 12 is minimized.
As shown in FIGS. 6A-6C, the tube fitting 28 includes an opening 52 formed therein having a minor portion 52 a which extends perpendicular to the spout axis and a major portion 52 b which extends generally parallel to the spout axis. The tube fitting 28 is received in the cavity 42 of the flow shaper 20, as shown in FIG. 4. As can be seen in FIGS. 5A-5D, the spacer 44 may include an opening 50, and the end 54 of the tube fitting 28 is received in the opening 50 of the spacer 44. The tube fitting 28, in the illustrated embodiment, has a groove 56 adjacent to the end 54 which is designed to receive a clip 58 of the flow shaper 20 therein to couple the tube fitting 28 to the flow shaper 20 (see FIG. 4).
In this manner, the distal end 54 of the tube fitting 28 fits into the opening 50 of the spacer 44, and helps to provide a generally fluid-tight spacer 44 through which fluid does not pass. However, the spacer 44 may not necessarily include the opening 50, and the tube fitting 28 may be coupled to the flow shaper 20 in any of a variety of manners. In addition, the flow shaper 20 can be retained in the spout 12 by any of a variety of means, such as by deforming the tip of the spout 12 radially inwardly or by the use of adhesives, staking, set screws, retaining rings, press fits, retaining collars, and the like.
After the tube fitting 28 is mounted to the flow shaper 20, and the flow shaper 20 is mounted in the spout 12, the minor portion 52 b of the opening 52 is in direct fluid communication with, or forms part of, the sensing port 22 (see FIG. 4) and the major portion 52 a of the opening 52 b is in direct fluid communication with the tube 26 (see FIG. 2). In this manner, the tube fitting 28 allows the pressure from the sensing port 22 to be communicated, via the tube 26, to the shut off circuit.
It should be noted that some previous arrangements for coupling the tube 26 to the sensing port 22 may provide an obstruction to flow which generates significant turbulence in the stream of fuel. However, in the flow shaper 20 (and other embodiments) disclosed herein, not only does the spacer 44 provide the function of reducing meniscus films which can cover the sensing port 22, but the spacer 44 also makes use of, and is aligned with, the tube fitting 28 so that the tube fitting 28 does not contribute additional turbulence. In other words, the flow shaper 20 incorporates what is otherwise a mere obstruction (the tube fitting 28) in the fuel path, into a functional arrangement.
FIG. 7 illustrates another embodiment 20 a of the fuel shaper. In this case, the fuel shaper 20 a has an outer wall 30, and a plurality of vanes 62 that divide the fuel shaper 20 a into a plurality of cavities 64. In the illustrated embodiment, the outer wall 30 is generally cylindrical (although the outer wall 30 can be shaped as desired to conform to the inner surface of the spout 12), and the vanes 62 are generally radially positioned and meet at the axial center of the fuel shaper 20 a.
In this case, the flow shaper 20 a has a plurality of cavities 64, each of which radially extends across generally the entire effective cross section thereof of the flow shaper 20 a (i.e. from the outer wall 30 to an inner section 68 which does not allow fluid flow therethrough). In this embodiment, each of the cavities 64 may have a sufficient L/D ratio (i.e. at least about 10:1 in one case, or at least about 8:1 or 7:1 in another case) such that the flow exiting each cavity 64 is fully developed or nearly fully developed. Thus, any of a variety of shapes and configurations for the flow shaper, vanes, and cavities may be used, and it may be desired that at least the majority of the outer perimeter of an exiting fluid stream, or at least a majority of the volume of the exiting fluid stream, be fully developed or nearly fully developed.
Another embodiment of the fuel flow shaper 20 b is shown in FIGS. 8A-D. In this embodiment the fuel flow shaper 20 b includes a series of inner walls 70, 72 defining a set of cavities 74. The inner walls include a set of three major arcs 70, wherein each major arc 70 extends from one point of the outer wall 30 to another point on the outer wall 30. In the illustrated embodiment, the ends of a major arc 70 are spaced apart by about 80° about the circumference of the outer wall 30. Each major arc 70 in the illustrated embodiment is a circular arc having a diameter about equal to the diameter of the outer wall 30. However, the diameter, shape, size and positioning of each major arc 70 may vary as desired.
The fuel flow shaper of FIGS. 8A-D also includes two minor arcs 72, with each minor arc 72 extending between two of the major arcs 70. In particular in the illustrated embodiment each minor arc 72 extends between the center or midsection of two adjacent major arcs 70, and the inner ends of the minor arcs 72 are positioned adjacent to each other at the center or midsection of the other major arc 70 opposite the spacer 44. Each minor arc 72 is entirely spaced apart from the outer wall 30. In the illustrated embodiment each minor arc 72 is a circular arc having a diameter about equal to the diameter of the outer wall 30, although the diameter, shape, size and positioning of the minor arcs 72 may vary as desired.
The arrangement shown in FIGS. 8A-8D (as well as the various other embodiments disclosed herein) provides a plurality of cavities 74, wherein cavity 74 has a L/D ratio to provide fully developed flow, or nearly fully developed flow, to fuel flowing therethrough. More particularly, all of the volume of the fluid exiting the fuel flow shaper 20 b may be fully developed, or nearly fully developed, to provide a stable flow of fluid. This, in turn, reduces or eliminates tumbling and rotary vortices elements in a manner sufficient to provide a stable fluid flow and sufficiently eliminate splash back.
In addition, in the embodiment of FIGS. 8A-8D (as well as the various other embodiment disclosed herein) the plurality of cavities 74 may have a weighed average L/D ratio of at least about 8:1, which has been experimentally confirmed to reduce or eliminate tumbling and rotary vortices elements in a manner sufficient to provide a stable fluid flow and sufficiently eliminate splash back. A weighed average L/D ratio of at least about 5:1 may, in certain cases, be sufficient to reduce or eliminate tumbling and rotary vortices elements in a manner sufficient to provide a stable fluid flow and sufficiently eliminate splash back. Each cavity 74 of the fuel flow shaper 20 b may have a surface area/cross sectional area that is within about 50% of any other cavity 74. By having cavities 20 b of roughly the same size, it can be ensured that fuel flowing through the fuel flow shaper 20 b is all fully developed, or nearly fully developed, and avoids flow having differing internal properties which can be difficult to control.
In the embodiment shown in FIGS. 8A-8D (as well as the other embodiment disclosed herein), the upstream end of each arc 70, 72 may be tapered such that fluid flow down the spout 12 first engages the radially outer ends of the arcs, as described above in the embodiment shown in FIGS. 5A-5D. In addition, in this and other embodiments, the downstream end of each arc 70, 72 may be spaced inwardly from the downstream end 40 of the shaper 20, as described above in the embodiment shown in FIGS. 5A-5D, to provide protection to the downstream ends of the inner walls 70, 72.
The fuel flow shaper 20 c shown in FIG. 9 is somewhat similar to the embodiment of FIGS. 8A-8D, but also includes an intermediate arc 80 extending between the center positions of two opposite major arcs 70. The intermediate arc 80 divides the core channel of the embodiment of FIGS. 8A-8D into two separate “core” channels 74′. The remaining major arcs 70, minor arcs 72 and channels/cavities 74 are slightly adjusted to accommodate the intermediate arc 80 to ensure the channels/ cavities 74, 74′ have roughly the same cross sectional area.
The fuel flow shaper 20 d shown in FIG. 10 is somewhat similar to the embodiment of FIG. 9. However, in the embodiment of FIG. 10 the intermediate arc 80 is not present. Instead, the fuel flow shaper 20 d includes an outer arc 82 positioned proximate to, and curving about, the spacer 44 to define a cavity therebetween. The outer arc 82 has a curvature in the opposite direction to the curvature of the intermediate arc 80 of the embodiment 20 c of FIG. 9.
The fuel flow shaper 20 e shown in FIG. 11 is somewhat similar to the embodiment of FIG. 10. However, in the embodiment of FIG. 11 the cavity defined by each major arc 70 is subdivided by a generally radially-extending stub wall 84 positioned therein. In addition, the core channel of the embodiment of FIG. 11 is divided by a transverse wall 86 extending between the minor arcs 72, and a stub wall 88 extending between the transverse wall 86 and the outer arc 82. One advantage of the embodiment shown in FIG. 11 is that the fuel flow shaper 20 e provides relatively small cavities 74, thereby providing a relatively high L/D ratio and improving the stability of flow exiting the stream shaper. One drawback with this design, however, is that the relatively small size of the cavities 74 increases the pressure drop of fluid flowing through the stream shaper. These principles holds generally true as additional walls are added from the fuel flow shaper 20 c of FIGS. 8A-D, to the fuel flow shaper 20 e shown in FIG. 11.
The fuel flow shaper 20 f of FIG. 12 provides a bit of a different approach than some of the other embodiments described herein. In particular, the fuel flow shaper 20 f of FIG. 12 has a plurality of generally circular inner walls 90 defining a plurality of generally circular cavities 92 positioned about a core chamber 94. A set of end chambers 96 are positioned adjacent to the series of circular cavities 92, and a plurality of remainder cavities 98 are positioned between the generally circular cavities 92 and the outer wall 30.
The fuel flow shaper 20 g shown in of FIG. 13 is a bit of a hybrid between the fuel flow shaper 20 f of FIG. 12 and those of FIGS. 8-11. In particular, the fluid flow shaper 20 f of FIG. 13 has a plurality of generally circular cavities 100 combined with a plurality of generally radially extending vanes/walls 102 extending outwardly from a core chamber 104. The radially extending walls 102 and generally circular cavities 100 are positioned about the core channel 104.
The fuel flow shaper 20 h of FIG. 14 includes a plurality of ribs 106 that generally follow the curvature of the lower side (in the orientation shown in FIG. 14) of the outer wall 30, and generally extend from one side of the outer wall 30 to another side (curving about the spacer 44). Each of the ribs 106 are coupled to, and extend generally outwardly from, a generally vertically extending/radially extending spine 108. The ribs 106 and spine 108 thereby define a plurality of cavities positioned therebetween.
Each of the various embodiments described and shown herein may follow one or more of the basic principles set forth herein, although such properties are not required. In particular, the cavities may be sized to provide fully developed flow, or nearly fully developed flow. The cavities may be sized to provide a weighted L/D ratio of at least about 8:1. Each cavity may have a L/D ratio of at least about 5:1 and less than about 20:1, or other values as desired. Each cavity may have a surface area that is within about 50% of any other cavity. The cavities may provide fully developed flow, or nearly fully developed flow, about an outer perimeter, or about a majority of the outer perimeter, of the fluid flow. The cavities may provide a fuel flow wherein at least a majority of the fuel flow, by volume, is fully developed flow, or nearly fully developed flow. Certain ones or more of these features and other features may help to reduce turbulence and provide a stable, confined fluid stream.
Having described the invention in detail and by reference to the various embodiments, it should be understood that modifications and variations thereof are possible without departing from the scope of the invention.

Claims

1. A system comprising:

a flow shaper configured to be positioned in a spout such that fuel flowing through said spout passes through said flow shaper and exits in a fuel stream, wherein said flow shaper includes an outer wall and a plurality of cavities formed therein, each cavity having a L/D ratio, wherein an average L/D ratio of said cavities, weighted by cross sectional area, is at least about 8:1.

2. The system of claim 1 further comprising a spout configured to dispense fuel therethrough, wherein said flow shaper is positioned in said spout.

3. The system of claim 2 wherein said flow shaper is positioned at a distal end of said spout.

4. The system of claim 2 wherein said flow shaper is configured such that each cavity receives part of said fuel stream therein and such that the entirety of said fuel stream collectively passes through said plurality of cavities.

5. The system of claim 2 wherein said flow shaper includes a spacer which blocks the flow of fuel therethrough, wherein said spacer has an outer portion positioned adjacent to said spout and extending at least about 60 degrees about an outer perimeter of said flow shaper.

6. The system of claim 5 wherein said spout includes a shut-off opening formed therein, and wherein said spacer is generally radially aligned with said shut-off opening.

7. The system of claim 2 further comprising a fuel reservoir and a hose fluidly coupled to said nozzle and said fuel reservoir, and a pump configured to pump fuel from said fuel reservoir, through said hose, to said nozzle and through said fuel shaper.

8. The system of claim 1 wherein an average L/D ratio of said cavities, weighted by cross sectional area, is less than about 20:1.

9. The system of claim 1 wherein said L/D ratio of each cavity is at least about 5:1.

10. The system of claim 1 wherein the L/D ratio for any given cavity is the ratio of the length of the given cavity to the hydraulic diameter of the given cavity.

11. The system of claim 1 wherein said flow shaper includes an outer wall and a plurality of vanes defining said plurality of cavities, wherein said plurality of vanes includes three major arcs, each major arc extending from one position on said outer wall to another, spaced apart position on said outer wall.

12. The system of claim 11 wherein each major arc is a circular arc, and wherein the plurality of vanes includes a pair of minor arcs, each minor arc extending between two associated major arcs.

13. The system of claim 12 wherein each minor arc extends between midsections of the associated major arcs.

14. The system of claim 1 further comprising a plurality of vanes defining said plurality of cavities, wherein an upstream end of each vane is tapered with respect to a direction of fluid flow through said spout.

15. The system of claim 1 wherein each cavity has a cross sectional area that is within at least about 50% of the cross sectional area of any other cavity.

16. The system of claim 1 wherein said flow shaper is configured such that at least a majority of the volume of said exiting fuel stream is fully developed or nearly fully developed fluid flow.

17. The system of claim 1 wherein said flow shaper is configured such that all of the volume of said exiting fuel stream is fully developed or nearly fully developed fluid flow.

18. The system of claim 1 wherein said flow shaper is configured such that all of the volume of said exiting fuel stream has a velocity profile that does not deviate from the velocity profile for fully developed flow of the fuel stream by more than about 20%.

19. The system of claim 1 further comprising liquid fuel flowing through said flow shaper and exiting from said flow shaper, wherein said exiting fuel stream is fully developed on nearly full developed flow.

20. The system of claim 1 wherein said flow shaper includes at least four cavities.

21. A system comprising:

a flow shaper configured to be positioned in a spout such that fuel flowing through said spout passes through said flow shaper and exits in a fuel stream, said flow shaper being configured such that at least a majority of the volume of said exiting fuel stream is fully developed or nearly fully developed fluid flow.

22. The system of claim 21 further comprising a spout configured to dispense fuel therethrough, wherein said flow shaper is positioned in said spout.

23. The system of claim 21 wherein said flow shaper includes a plurality of cavities positioned such that each cavity receives part of said fuel stream therein and such that the entirety of said fuel stream collectively passes through said plurality of cavities, each cavity having a L/D ratio, wherein an average L/D ratio of said cavities, weighted by cross sectional area, is at least about 8:1.

24. The system of claim 22 wherein an average L/D ratio of said cavities, weighted by cross sectional area, is less than about 20:1.

25. The system of claim 21 wherein said flow shaper includes a plurality of cavities configured such that each cavity receives part of said fuel stream therein and such that the entirety of said fuel stream collectively passes through said plurality of cavities, each cavity having a L/D ratio, wherein said L/D ratio of each cavity is at least about 5:1.

26. The system of claim 21 wherein said flow shaper includes a plurality of cavities configured such that each cavity receives part of said fuel stream therein and such that the entirety of said fuel stream collectively passes through said plurality of cavities, wherein each cavity has a cross sectional area that is within at least about 50% of the cross sectional area of any other cavity.

27. The system of claim 21 wherein said flow shaper includes an outer wall and a plurality of vanes defining said plurality of cavities, wherein said plurality of vanes includes three major arcs, each major arc extending from one position on said outer wall to another, spaced apart position on said outer wall.

28. The system of claim 21 wherein said flow shaper is configured such that all of the volume of said exiting fuel stream is fully developed or nearly fully developed fluid flow.

29. The system of claim 21 further comprising liquid fuel flowing through said flow shaper and exiting from said flow shaper in a fuel stream, wherein at least a majority of the volume of said exiting fuel stream is fully developed or nearly fully developed fluid flow.

30. The system of claim 21 wherein said flow shaper is configured such that all of the volume of said exiting fuel stream has a velocity profile that does not deviate from the velocity profile for fully developed flow of the fuel stream by more than about 20%.

31. The system of claim 21 wherein said flow shaper includes a spacer which blocks the flow of fuel therethrough, wherein said spacer has an outer portion positioned adjacent to said spout and extending at least about 60 degrees about an outer perimeter of said flow shaper.

32. The system of claim 31 wherein said spout includes a shut-off opening formed therein, and wherein said spacer is generally radially aligned with said shut-off opening.

33. The system of claim 21 further comprising a fuel reservoir and a hose fluidly coupled to said nozzle and said fuel reservoir, and a pump configured to pump fuel from said fuel reservoir, through said hose, to said nozzle and through said fuel shaper.

34. A system comprising:

a flow shaper configured to be positioned in a spout such that fuel flowing through said spout passes through said flow shaper and exits in a fuel stream, wherein said flow shaper includes an outer wall and a plurality of cavities formed therein, each cavity having a L/D ratio of at least about 5:1.

35. A method for dispensing fuel comprising:

providing an nozzle system having a spout with a flow shaper positioned therein; and

causing fuel to flow through said nozzle system, said spout and said flow shaper such that fuel flowing through said spout passes through said flow shaper and exits in a fuel stream such that that at least a majority of the volume of said exiting fuel stream is fully developed or nearly fully developed flow.