ANTI-SIPHON DEVICE
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional Patent
Application Serial No.: 61/177,018, filed on May 11, 2009, the disclosure of which is
hereby incorporated by reference.
TECHNICAL FIELD
[0002] The invention generally relates to an anti-siphon device for a fuel storage
system of a vehicle, and a method of assembling the fuel storage system including the
anti-siphon device.
BACKGROUND
[0003] Fuel storage systems for storing a fuel for a vehicle generally include a
tank, a check valve, and a fuel intake tube. The tank stores the fuel until needed by an
engine. The check valve is coupled to the tank, and is configured to allow fuel flow
from the fuel intake tube into the tank and prevent fuel flow in an opposite direction out
of the tank and back through the fuel intake tube.
[0004] In order to prevent siphoning of the fuel stored within the tank, the fuel
storage system may include an anti-siphon device. The anti-siphon device is disposed
somewhere within or between the fuel intake tube and/or the check valve. The anti-
siphon device prevents passage of an object, e.g., a siphon tube, therethrough, thereby
preventing siphoning of the fuel stored within the tank.
[0005] Anti-siphon devices for gasoline powered vehicles have previously
included a mesh screen or the like having many small sized apertures through which the
fuel flows when filling the tank. For alcohol based fuels, such as E-85, the large
apertures tend to vaporize a larger percentage of the alcohol based fuel during filling
than occurs with gasoline. The increased vaporization of the alcohol based fuel
increases the backpressure within the tank, which reduces the storage capacity of the

tank, or alternatively, requires a larger carbon canister to compensate for the increased
fuel vaporization.
[0006] Furthermore, fluid and/or vapor backpressure within the fuel storage
system may lead to a premature shut-off condition, in which a fuel filler nozzle
automatically shuts off when the back pressure rises above a certain level. The back
pressure within the fuel system may be caused by flow obstructions, such as a fill pipe
diameter, a sharp bend in the fill pipe, a static pressure head of the fuel in the fuel tank,
a check valve in the fill pipe, etc.
SUMMARY
[0007] An anti-siphon device for a fuel storage system is provided. The anti-
siphon device includes a ring concentric with a longitudinal axis and defining an
interior opening.. At least one fin spanning across the interior opening of the ring and
having a depth extending away from the ring along the longitudinal axis. The interior
opening of the ring defines a diameter. The ring abuts an end of a tube having an inner
diameter substantially equal to the diameter of the interior opening of the ring, such that
the ring supports the at least one fin within the tube without substantially narrowing the
inner diameter of the tube, thereby minimizing a fluid pressure drop through the tube
during refilling.
[0008] A fuel storage system for a vehicle is also provided. The fuel storage
system includes a tank defining an inlet. A check valve is coupled to the tank and in
fluid communication with the inlet of the tank. The check valve includes an inlet tube,
and is configured for permitting fuel flow into the tank and preventing fluid flow from
the tank. The fuel storage system further includes a fuel intake tube coupled to the
check valve, and an anti-siphon device disposed between and rotatably positionable
relative to the check valve and the fuel intake tube. The anti-siphon device includes a
ring concentric with a longitudinal axis. The ring defines an interior opening. The
anti-siphon device further includes at least one fin spanning across the interior opening
of the ring and having a depth extending away from the ring along the longitudinal axis.
The interior opening of the ring defines a diameter. The ring abuts an end of the inlet

tube having an inner diameter substantially equal to or smaller than the diameter of the
interior opening of the ring, such that the ring supports the at least one fin within the
inlet tube without substantially narrowing the inner diameter of the inlet tube, thereby
minimizing a fluid pressure drop through the inlet tube during refilling.
[0009] A method of assembling a fuel storage system for a vehicle is also
provided. The fuel storage system includes a tank, a check valve having an inlet tube,
an anti-siphon device and a fuel intake tube. The method includes coupling the check
valve to the tank, positioning the anti-siphon device at an upstream end of the inlet tube
of the check valve, and orienting the anti-siphon device relative to the fluid flow to
maximize fluid flow through the anti-siphon device. The method further includes
attaching the fuel intake tube to the check valve to secure the position of the auti-siphon
device therebetween, relative to the check valve.
[0010] Accordingly, the ring of the anti-siphon device supports the fins without
interfering and/or otherwise restricting with the flow of fuel through the anti-siphon
device, thereby decreasing any reduction in flow caused by the anti-siphon device.
Additionally, the fins are sized, spaced and oriented relative to the direction of
incoming fuel flow to minimize vaporization of the fuel during filling of the tank.
[0011] The above features and advantages and other features and advantages of
the present invention are readily apparent from the following detailed description of the
best modes for carrying out the invention when taken in connection with the
accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] Figure 1 is a schematic side plan view of a fuel storage system for a
vehicle.
[0013] Figure 2 is a schematic perspective view of an anti-siphon device of the
fuel storage system.
[0014] Figure 3 is a schematic top plan view of the anti-siphon device.
[0015] Figure 4 is an exploded partial schematic cross sectional view of the fuel
storage system showing the anti-siphon device.

[0016] Figure 5 is a partial schematic cross sectional view of the fuel storage
system, perpendicular to the view shown in Figure 4, showing the anti-siphon device.
DETAILED DESCRIPTION
[0017] Referring to the Figures, wherein like numerals indicate corresponding
parts throughout the several views, a fuel storage system is shown generally at 20 in
Figure 1. The fuel storage system 20 stores a fuel for a vehicle. The fuel may include
any suitable type of fuel, such as but not limited to, an alcohol based fuel such as E-85,
or gasoline. However, the fuel storage system 20 disclosed herein is particularly well
suited for storing alcohol based fuels.
[0018] The fuel storage system 20 includes a tank 22. The tank 22 may be sized
and/or configured in any suitable manner to meet the design considerations specific to
the vehicle. Additionally, the tank 22 may be manufactured from any suitable material,
including but not limited to, a metal or a plastic material. The tank 22 defines an inlet
24, through which the fuel flows to fill the tank 22. The inlet 24 may be sized and
located on the tank 22 in any manner suitable to meet the specific design requirements
of the vehicle. The tank 22 further includes an outlet (not shown), through which the
fuel is dispensed to an engine of the vehicle.
[0019] The fuel storage system 20 further includes a check valve 26. The check
valve 26 is coupled to the tank 22. As shown, the check valve 26 is directly attached to
the tank 22. However, it should be appreciated that the check valve 26 may be coupled
to the tank 22 by an intervening component, such as but not limited to, a hose, a
connector, a tube or the like. The check valve 26 is in fluid communication with the
inlet 24 of the tank 22. The check valve 26 permits fluid flow in a single direction
only. It should be appreciated that as used herein, the term fluid flow includes, but is
not limited to, liquid flow or vapor flow. Accordingly, the check valve 26 is
configured for permitting fuel flow into the tank 22, and prevents fluid flow from
exiting the tank 22 through the inlet 24 of the tank 22.
[0020] Specific to me detailed description of me invention, the check valve 26
includes an inlet tube 28 disposed at an upstream end of the check valve 26. As such,

the fuel flowing into the tank 22 enters the check valve 26 at and through the inlet tube
28. Accordingly, the check valve 26 may include any check valve 26 having an inlet
tube 28 disposed at the upstream end of the check valve 26 that is suitable for use in a
fuel system of a vehicle, and is capable of allowing fluid flow into the tank 22 and
blocking fluid flow out of the tank 22.
[0021] The fuel storage system 20 further includes a fuel intake tube 30. The
fuel intake tube 30 is coupled to the check valve 26, and extends generally upward to
and is coupled to a structural element 31 of the vehicle. More specifically, the fuel
intake tube 30 is coupled to the inlet tube 28 of the check valve 26. The fuel intake
tube 30 may be coupled to the check valve 26 in any suitable manner, including but not
limited to, with a clamp or the like. As shown, the fuel intake tube 30 includes a single
portion. However, it should be appreciated that the fuel intake tube 30 may include
multiple portions sized and configured to fit together as required to meet the specific
design constraints of the vehicle.
[0022] Referring also to Figures 2 through 5, the fuel storage system 20 further
includes an anti-siphon device 32. The anti-siphon device 32 prevents an object from
passing through the anti-siphon device 32 and into the tank 22, to prevent siphoning of
the fuel stored within the tank 22. As shown, the anti-siphon device 32 is disposed
between the check valve 26 and the fuel intake tube 30. Alternatively, if the fuel intake
tube 30 includes multiple sections, then the anti-siphon device 32 may be disposed
between two adjoining portions of the fuel intake tube 30.
[0023] The anti-siphon device 32 includes a ring 34, which is concentric with a
longitudinal axis 36. As shown, the ring 34 includes an annular shape, and defines an
interior opening 38 defining an annular shape as well. However, the ring 34 and the
interior opening 38 may be shaped other than shown and described herein. As shown
in Figures 4 and 5, the ring 34 and the interior opening 38 are shaped to match the
shape of the intake tube of the check valve 26 and/or the fuel intake tube 30.
[0024] The anti-siphon device 32 includes at least one fin 40. The number of
fins 40 should be as few a possible to minimize fluid pressure drop , yet still sufficient
in number to block passage of an object of a pre-determined size, including but not

limited to an object having an outside diameter of 5.2 mm or larger. As shown, the at
least one fin 40 includes a plurality of fins 40. More specifically, the plurality of fins
40 includes three fins 40. However, the number of fins 40 depends upon the size of the
ring 34 and the size of the object that the anti-siphon device 32 must block.
Accordingly, the number of fins 40 may be greater than or less than the three fins 40
shown in the drawings. As shown, the fins 40 span across the interior opening 38 of
the ring 34 in parallel relationship with each other, and extend along the longitudinal
axis 36. However, it should be appreciated that the fins 40 may be configured in any
other manner that minimizes obstruction to a cross sectional flow area.
[0025] The fins 40 extend from the ring 34 to a distal edge 42. As shown in
Figures 2 and 5, the distal edge 42 of each of the fins 40 defines a semi-circular cut-out
44 that is perpendicular to the longitudinal axis 36. The semi-circular cut-out 44
defines the depth of the fin 40 from the ring 34 along the longitudinal axis 36. The fin
40 depth is shallowest at the center of a flow path defined by the inlet tube 28 or the
fuel intake tube 30, where the fluid flow rate is higher. The fin 40 depth is deepest
near the periphery of the fluid flow path, i.e., adjacent the walls of the inlet tube 28
and/or the fuel intake tube 30, where the fluid flow rate is lower. By reducing the fin
40 depth where the fluid flow rate is higher, and increasing the fin 40 depth where the
fluid flow rate is lower, the fins 40 minimize turbulence in the fluid passing through the
anti-siphon device 32, thereby decreasing the fluid pressure drop and nunirnizing any
vaporization of the fluid passing through the anti-siphon device 32.
[0026] Referring to Figure 4, the fins 40 may have an airfoil-shaped cross
section taken perpendicular to the longitudinal axis 36, and perpendicular to the semi-
circular cut-out 44. More specifically, the airfoil shape of the fins 40 includes a first
edge 46, a second edge 48 and a middle section 50. The middle section 50 is disposed
between the first edge 46 and the second edge 48. The first edge 46 and the second
edge 48 may include a thickness between the range of 0.5 mm and 1.0 mm. The
middle section 50 may include a thickness between the range of 0.75 mm and 1.5 mm.
Accordingly, the thickness of the fins 40 increases toward the midsection of the fins 40.
The airfoil shape of (he fins 40 minimizes turbulence in the fluid passing through the

anti-siphon device 32, thereby decreasing the pressure drop and minimizing any
vaporization of the fluid passing through the anti-siphon device 32.
[00271 Referring to Figures 2 through 5, the anti-siphon device 32 may include
at least one projection 52 extending radially inward toward the longitudinal axis 36, and
perpendicular to the fins 40. As shown in Figure 3, the at least one projection 52 may
include a first projection 52a, a second projection 52b, a third projection 52c and a
fourth projection 52d. However, the specific number of projections 52 depends upon
the size of the ring 34 and the size of the object that the anti-siphon device 32 must
block. Accordingly, the number of projections 52 may vary from that shown and
described herein. In this embodiment, the first projection 52a, the second projection
52b, the third projection 52c and the fourth projection 52d each extend inwardly from
the ring 34, into the interior opening 38 of the ring 34 and perpendicularly relative to
the fins 40. The first projection 52a and the second projection 52b are disposed on
opposite sides of the fins 40 relative to the third projection 52c and the fourth projection
52d. The fins 40 and the projections 52 cooperate to prevent passage of an object, such
as a siphon hose, through the anti-siphon device 32. As such, the projections reduce
obstruction of the cross sectional fluid flow area to minimize drag and/or fluid pressure
drop while still preventing passage of the object. As shown, the three fins 40, the first
projection 52a, the second projection 52b, the third projection 52c and the fourth
projection 52d cooperate to prevent an object having an outer diameter of at least 5.0
mm from passing through the interior opening 38 of the ring 34. However, as
described above, the fins 40 and the projections 52 may be configured other than shown
and described herein to block an object of a different size. However, the number of
fins 40 and the number of projections 52 should be configured for a given application to
minimize restriction of the fluid flow path of the inlet tube 28 and/or the fuel intake
tube 30 and not impede fluid flow into the tank 22, mereby rrunirnizing vaporization of
the fluid passing through the anti-siphon device 32. In other words, the number of fins
40 and the number of projections 52 may be minimized for a given application.
[0028] Referring to Figures 4 and 5, the interior opening 38 of the ring 34 is
sized to match the fluid flow path defined by the inlet tube 28 and/or the fuel intake

tube 30. As shown, the interior opening 38 of the ring 34 defines a diameter 54 that is
substantially equal to or larger than a diameter 56 of the inlet tube 28 and/or the fuel
intake tube 30. A body 58 of the ring 34 extends radially outward from the
longitudinal axis 36, away from the interior opening 38 and the fluid flow path defined
by the inlet tube 28 and/or the fuel intake tube 30, such that the body 58 of the ring 34
does not interfere with fluid flow through the inlet tube 28 and/or the fuel intake tube
30. As shown, the ring 34 is configured for abutting an end of a tube. More
specifically, the ring abuts the inlet tube 28. However, as described above, the fuel
storage system 20 may be configured such that the ring abuts an end of the fuel intake
tube 30. The inlet tube 28 includes an inner diameter 56 substantially equal to or
smaller than the diameter 54 of the interior opening 38 of the ring 34 such that the ring
34 supports the plurality of fins 40 within the inlet tube 28 without narrowing the inner
diameter 56 of the inlet tube 28, maximizing fluid flow through the inlet tube 28.
Therefore, only the fins 40, the first projection 52a, the second projection 52b, the
third projection 52c and the fourth projection 52d extend into the interior opening 38,
and are disposed within the fluid flow path defined by the inlet tube 28, with the ring
34 being disposed outside the fluid flow path. Accordingly, the ring 34 does not
impede the fluid flow through the fluid flow path, thereby minimizing vaporization of
the fluid flowing through the anti-siphon device 32.
[0029] The upstream end of the inlet tube 28 of the check valve 26 includes a
chamfered edge 60. The ring 34 includes a chamfered edge 62 on a downstream edge,
which abuts the chamfered edge 60 of the inlet tube 28. The mating chamfered edges
60, 62 cooperate to position the anti-siphon device 32 relative to the check valve 26,
and perpendicular to the longitudinal axis 36. It should be appreciated that if the anti-
siphon device 32 is disposed between different portions of the fuel intake tube 30, then
an upstream edge of one of the portions of the fuel intake tube 30 would define 40 the
chamfered edge 60 for the chamfered edge 62 of the ring 34 to mate against.
[0030] Assuming the anti-siphon device 32 is circularly shaped, as shown and
described herein, the anti-siphon device 32 is rotatably positionable relative to the check
valve 26 and the fuel intake tube 30. In other words, the anti-siphon device 32 is

separate from the check valve 26 and the fuel intake tube 30, and may be rotated about
the longitudinal axis 36 to position the anti-siphon device 32 relative to the check valve
26 and the fuel intake tube 30. By rotating the anti-siphon device 32, the fins 40 may
be aligned with a fluid flow direction that minimizes obstructions in the fluid flow path.
For example, if the fuel intake tube 30 has a bend immediately upstream from me anti-
siphon device 32, the anti-siphon device 32 may be routed so that the fluid does not
impinge upon the fins 40 and that the fins 40 align with the plane of curvature. This
alignment minimizes the fluid pressure drop as the fuel follows the bend, thereby
reducing potential vaporization of the fluid.
[0031] As described herein, the anti-siphon device 32 is configured to minimize
vaporization and minimize fluid pressure drop through the anti-siphon device 32. In so
doing, the anti-siphon device 32 of the present invention is particularly useful when
used with an alcohol based fuel, such as E-85, which vaporizes much more easily than
gasoline and can generate excessive backpressure during refilling, triggering premature
nozzle shutoff. Backpressure within the fuel storage system 20 is reduced by
minimizing the vaporization, and maximizing the fluid flow rate through the anti-siphon
device 32. Accordingly, by minimizing the backpressure within the fuel storage system
20, the fuel storage system 20 may operate properly regardless of fuel type.
Additionally, excessive vaporization of the fuel flowing through the anti-siphon device
32 may decrease the storage capacity of the tank 22. By decreasing the vaporization of
the fuel, particularly for alcohol based fuels, the anti-siphon device 32 maximizes the
storage capacity of a canister system.
[0032] Referring back to Figure 1, a method of assembling the fuel storage
system 20 described above is provided. The method includes coupling the check valve
26 to the tank 22. As described above, the check valve 26 may be coupled directly or
indirectly to the tank 22 in any suitable manner, including but not limited to, clamping.
[0033] The method further includes positioning the anti-siphon device 32 within
the fluid flow path. The anti-siphon device 32 may be positioned at an upstream end of
the inlet tube 28 of the check valve 26. Alternatively, the anti-siphon device 32 may be
positioned between adjoining portions of the fuel intake tube 30.

[0034] The method further includes orienting the anti-siphon device 32 relative
to the fluid flow to increase fluid flow through the anti-siphon device 32. More
specifically, orienting the anti-siphon device 32 relative to the fluid flow includes
rotating the anti-siphon device 32 until the plurality of fins 40 are arranged in an
orientation that reduces impingement of the fluid on the fins 40.
[0035] The method further includes securing the position of the anti-siphon
device 32. The position of the anti-siphon device 32 may be secured by attaching the
fuel intake tube 30 to the check valve 26 to secure the position of the anti-siphon device
32, relative to the check valve 26. The fuel intake tube 30 may be attached to the inlet
tube 28 of the check valve 26 in any suitable manner, including but not limited to,
clamping or other similar method. Alternatively, if the anti-siphon device is disposed
between adjoining portions of the fuel intake tube 30, the anti-siphon device 32 may be
secured by attaching the adjoining portions of the fuel intake tube 30.
[0036] Positioning the anti-siphon device 32 adjacent to and in abutting
engagement with the inlet tube 28 of the check valve 26, with the check valve 26
directly attached to the tank 22, as is shown in Figure 1, provides for convenient
disassembly and emptying of the tank 22. When so constructed, the fuel intake tube 30
may be disconnected from the inlet tube 28 of the check valve 26 and the anti-siphon
device 32. After the anti-siphon device 32 is removed, a siphon tube may then be
inserted into the tank 22 to drain the tank 22.
[0037] While the best modes for carrying out the invention have been described
in detail, those familiar with the art to which this invention relates will recognize various
alternative designs and embodiments for practicing the invention within the scope of the
appended claims.

we claim:
1. An anti-siphon device (32) for a fuel storage system (20), the
anti-siphon device (32) comprising:
a ring (34) concentric with a longitudinal axis (36) and defining an
interior opening (38); and
at least one fin (40) spanning across the interior opening (38) of the ring
(34) and having a depth extending away from the ring (34) along the longitudinal axis
(36);
wherein the interior opening (38) of the ring (34) defines a diameter (54)
and wherein the ring (34) abuts an end of a tube (28), (30) having an inner diameter
(56) substantially equal to the diameter (54) of the interior opening (38) of the ring (34)
such that the ring (34) supports the at least one fin (40) within the tube (28), (30)
without substantially narrowing the inner diameter (56) of the tube (28), (30), thereby
minimizing a fluid pressure drop through the tube (28), (30) during refilling.
2. An anti-siphon device (32) as set forth in claim 1 wherein the at
least one fin (40) extends from the ring (34) to a distal edge (42), wherein the distal
edge (42) defines a semi-circular cut-out (44) when viewed in a direction perpendicular
to the longitudinal axis (36).
3. An anti-siphon device (32) as set forth in claim 2 wherein the at
least one fin (40) includes a cross section defining an airfoil shape when viewed in a
direction perpendicular to the longitudinal axis (36) and perpendicular to the semi-
circular cut-out (44).
4. An anti-siphon device (32) as set forth in claim 3 wherein the
airfoil shape of the at least one fin (40) includes a first edge (46), a second edge (48),
and a middle section (50) disposed between the first edge (46) and the second edge
(48), wherein the first edge (46) and the second edge (48) include a thickness between

the range of 0.5 mm and 1.0 mm, and the middle section (50) includes a thickness
between the range of 0.75 mm and 1.5 mm.
5. An anti-siphon device (32) as set forth in claim 1 further
including at least one projection (52) extending inward from the ring (34) into the
interior opening (38) of the ring (34).
6. An anti-siphon device (32) as set forth in claim 6 wherein the at
least one projection (52) includes four projections (52a, 52b, 52c, 52d), wherein a first
projection (52a) and a second projection (52b) are disposed on opposite sides of the at
least one fin (40) relative to a third projection (52c) and a fourth projection (52d).
7. An anti-siphon device (32) as set forth in claim 6 wherein the at
least one fin (40) and the at least one projection (52) cooperate to prevent passage of an
object having an outer diameter of at least 5.0 mm from passing through the interior
opening (38) of the ring (34).
8. An anti-siphon device (32) as set forth in claim 6 wherein only
the at least one projection (52) and the at least one fin (40) are disposed within a fluid
flow path defined by the tube (28), (30), with the ring (34) disposed outside the fluid
flow path defined by tie tube (28), (30).
9. A fuel storage system (20) for a vehicle, the fuel storage system
(20) comprising:
a tank (22) defining an inlet (24);
a check valve (26) coupled to the tank (22) and in fluid communication
with the inlet (24) of the tank (22) and including an inlet tube (28), the check valve (26)
configured for permitting fuel flow into the tank (22) and preventing fluid flow from
the tank (22);
a fuel intake tube (30) coupled to the check valve (26); and

an anti-siphon device (32) disposed between and rotatably positionable
relative to the check valve (26) and the fuel intake tube (30), the anti-siphon device (32)
including:
a ring (34) concentric with a longitudinal axis (36) and defining
an interior opening (38); and
at least one fin (40) spanning across the interior opening (38) of
the ring (34) and having a depth extending away from the ring (34) along the
longitudinal axis (36);
wherein the interior opening (38) of the ring (34) defines a
diameter (54) and wherein the ring (34) is abuts an end of the inlet tube (28) having an
inner diameter (56) substantially equal to or smaller than the diameter (54) of the
interior opening (38) of the ring (34) such that the ring (34) supports the at least one fin
(40) within the inlet tube (28) without substantially narrowing the inner diameter (56) of
the inlet tube (28), thereby minimizing a fluid pressure drop through the inlet tube (28)
during refilling.
10. A fuel storage system (20) as set forth in claim 9 wherein the at
least one fin (40) extends from the ring (34) to a distal edge (42), wherein the distal
edge (42) defines a semi-circular cut-out (44) when viewed in a direction perpendicular
to the longitudinal axis (36).
11. A fuel storage system (20) as set forth in claim 10 wherein the at
least one fin (40) includes a cross sectional shape when viewed in a direction
perpendicular to the longitudinal axis (36) and perpendicular to the semi-circular cut-out
(44) defining an airfoil shape.
12. A fuel storage system (20) as set forth in claim 11 wherein the
airfoil shape of the at least one fin (40) includes a first edge (46), a second edge (48),
and a middle section (50) disposed between the first edge (46) and me second edge
(48), wherein the first edge (46) and the second edge (48) include a thickness between

the range of 0.5 mm and 1.0 mm, and the middle section (50) includes a thickness
between the range of 0.75 mm and 1.5 mm.
13. A fuel storage system (20) as set forth in claim 9 further
including a first projection (52a), a second projection (52b), a third projection (52c) and
a fourth projection (52d) extending inward from the ring (34) into the interior opening
(38) of the ring (34), perpendicular relative to the at least one fin (40), wherein the first
projection (52a) and the second projection (52b) are disposed on opposite sides of the at
least one fin (40) relative to the third projection (52c) and the fourth projection (52d).
14. A fuel storage system (20) as set forth in claim 15 wherein only
the at least one fin (40), the first projection (52a), the second projection (52b), the third
projection (52c) and the fourth projection (52d) are disposed within a fluid flow path
defined by the inlet tube (28), with the ring (34) disposed outside the fluid flow path
defined by the inlet tube (28).
15. A fuel storage system (20) as set forth in claim 9 wherein the
inlet tube (28) of the check valve (26) includes an upstream end defining a chamfered
edge (60), and wherein the ring (34) includes a chamfered edge (62) in abutting
engagement with the chamfered edge (60) of the inlet tube (28) and cooperating with
the chamfered edge (60) of the inlet tube (28) to position the anti-siphon device (32)
relative to the check valve (26), perpendicular to the longitudinal axis (36).

A fuel storage system (20) includes a tank (22), a
check valve (26) having an inlet tube (28), an anti-siphon
device (32) and a fuel intake tube (30) . The
anti-siphon device (32) includes a ring (34) defining
an interior opening (38) having a diameter (54) . The
ring (34) abuts an upstream end of the inlet tube (28)
of the check valve (26), which includes an inner
diameter (56) substantially equal to the diameter (54)
of the interior opening (38) of the ring (34). The ring
(34) includes and supports a plurality of fins (40)
within the inlet tube (28) without narrowing the inlet
tube (28) to maximize fluid flow through the inlet tube
(28). The anti-siphon device (32) is rotatable relative
to the check valve (26) and the fuel intake tube (30).
The shape, size and orientation of the fins (40) are
optimized to minimize flow interruption through the
anti-siphon device (32) and minimize vaporization of
the fluid.