Note: Descriptions are shown in the official language in which they were submitted.
1207S9~
SPECIFICAT:CON
The present invention relates to siphons and
vortex devices, and particularly to a method of and
apparatus for transferring liquid from one compartment
to another compartment of a sealed container utilizing
the partial vacuum created in the output passage of
the vortex device as the siphon initiating force.
With the development in recent years of very
small compact vehicles, problems have arisen as a
result of reduction in available space for various
elements of the vehicle. In a recent design of a
motor vehicle, a vertical indentation must be provided
in the bottom surface of the gas tank to accommodate
the car's tail pipe while maintaining the gas tank
in an acceptable position both with respect to the
ground and the rear of the vehicle. The problem with
such an arrangement is that the vertical indentation
in the bottom of the tank presents an obstacle to
the free flow of liquid from at least one of the compart-
ments formed by the obstacle.
In a particular vehicle which uses a throttle
body injector, a turbine pump is located in the gas
tank for pumping fluid to the injector. The pump
can withdraw liquid from only one side of the vertical
obstacle; bein~ a sump-type pump it does not have
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~2()7590
sufficient negative pressure to draw liquid over the
obstacle. The sump pump is preferred because of its
high efficiency. In such a system, it is critical
that no material reduction in pressure be encountered
in the flow from the pump to the throttle body injector
thus prohibiting the use of venturis. Further, the
system cannot tolerate the diversion of an appreciable
quantity of liquid being pumped to the injector. A
further constraint on the system is that moving parts
such as ball valves, spring biased valves, etc., cannot
be tolerated in such an environment. To date, a suitable
solution has not been found to this problem.
Brlef Description of the Present Invention
In accordance with one aspect of the present
invention, a vortex valve, driven hy liquid flow from
a sump-type pump is employed to transfer liquid from
a first compartment to a second compartment and i~
one embodiment of the invention, to transfer liquid
in both directions depending upon which compartment
has the higher level of liquid.
In accordance with one embodiment of the present
invention, the vortex device which is driven by the
sump pump is utilized to create a sufficient suction
in a siphon tube to raise the le~el of liquid therein
i
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over the obstacle and initiate a siphoning action
between the compartment remote from the pump and the
compartment in which the pump is located. The vortex
valve may be located in series with the flow of fluid
from the pump to the throttle body injector or may
be in effect a shunt to ground, that is, may tap off
a small amount of liquid from the conduit leading
to the throttle body injector internally of the gas
tank and return the small amount of diverted fluid
to the tank.
In a situation where the vortex valve is in
series with the flow from the pump to the conduit,
a vortex valve having a relatively small pressure
drop is utilized; the pressure drop being controlled
by the relative radii of the main vortex valve chamber
and the outlet passage. In a system where the vortex
valve constitutes a shunt to ground or shunt to sump,
the ratio of the radius of the vortex chamber to the
radius of the outlet passage is made quite large so
that a very high impedance to flow is developed and
relatively little fluid is diverted from the main
flow.
The theory underlying vortex valves and vortex
amplifiers which ever term is preferred may be found
in U.S. Patents as follows: 3,276,259; 3,320,815;
3,413,995; 3,410,143; 3,504,688 and the like.
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The specific problem with which the present
- invention must treat arises when one understands that
the pump wh1ch is preferred in the particular environment
with which the present invention is dealing is a sump
pump or, specifically, a pump that extends down into
the body of liquid and uses blades or other means
to move the liquid in which it is emersed up into
the conduit. As a result, virtually no negative pressure
is developed on the input side of the pump. Thus,
it is not possible to employ a pump generated negative
pressure or partial vacuum to draw fluid through a
siphon tube over the indentation or obstacle in the
floor of the gas tank. Since the outflow from the
pump is the only moving fluid available, this flow
must be utilized to initiate the vacuum.
In accordance with another feature of the
present invention, a siphon tube extends between the
two isolated chambers. A vacuum tube enters this
siphon tube at approximately its maximum vertical
height so that suction in the vacuum tube pulls fluid
equally from both chambers to the height of the vacuum
tube and perhaps partially into the vacuum tube. In
consequence, the siphon tube is maintained full of
liquid at all times, and once the level of fluid in
the compartment in which the pump is located falls
below the maximum height of the vertical indentation
~2Q75~0
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or obstacle in the tank, fluid begins to flow from
the isolated chamber into the chamber containing
the pump or vice versa if due to a bump or inclination
of the vehicle, the liquid in the pump compartment
is higher than in the other compartment.
As indicated above, it is known that a vortex
valve will, in its output passage, develop a negative
pressure which can be made quite high depending upon
the physical construction of the device. Supply
pressures of 10-15 psi are quite common and in the
particular environment under consideration, a resulting
negative pressure of 4 inches at the output of the
vortex is readily obtainable and is sufficient
for the intended purpose.
In other embodiments of the present invention,
the vortex valve is inserted in the tube extending
between the two compartments whereby the suction
created by flow of liquid through the vortex device
pulls up the liquid in the isolated compartment and
directs it to the other chamber along with the liquid
flowing through the vortex valve. By proper proportioning
of the device, it will operate as a one-way or a
two-way pump. In the former case, fluid is constantly
pumped from the remote compartment to the compartment
with the pump so long as the differential in levels
is within a prescribed range. In the latter case,
590
the device moves the fluid alternatively in one or
the other direction again depending upon the difference
in levels of liquid with a central dead band being
provided to prevent constant movement of fluid.
The advantage of this latter configuration
is that only one sender is required to provide a proper
fuel level reading. If two-way flow is not provided,
then two fuel gauge senders would be required; one
in each compartment, together with proper proportioning
based on capacity of each compartment in order to
provide a relatively accurate reading of remaining
fuel. By using a two-way siphon, the levels in the
; compartments are held within acceptable height variations. One of the most important features of the
present invention is that the controlling orifice,
the outlet orifice of the vortex unit, is physically
considerably larger than a venturi of comparable performance
capability and is far less subject to clogging or
damage in the dirty environment of a gas tank and
does not.require filtering which would be a service
nightmare.
It is an object of the present invention to
provide a system for moving liquid from one compartment
into another compartment separated by a vertical
~.;20~7590
g
obstacle by means of a siphon tube wherein liquid
~ is maintained in the siphon tube at least at the maximum
height of the siphon tube by a vacuum line sensing
the reduced pressure region of a vortex valve.
It is another object of the present invention
to utilize a low pressure drop vortex valve to develop
a negative pressure in a suction tube for purposes
of raising liquid in a siphon tube to a height exceeding
the vertical height of an obstacle between the two
containers adapted to contain liquid.
Another object of the present invention is
to utilize the negative pressure in or adjacent to
the outlet passage of a vortex valve for purposes
of causing flow of fluid between compartments either
by siphoning or pumping or a combination of both.
It is yet another object of the present invention
to provide a vortex valve for diverting a small portion
of the fluid flowing in a main conduit to develop
a negative pressure in the output passage of the vortex
valve whereby to cause fluid to flow between two compart-
ments by siphoning, pumping or a combination of both
effects.
,
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Brief Descrip~ion of the Drawings
Figure 1 is a simplified diagrammatic view
of one embodiment of the present invention.
Figure 2 is a plan view of a vortex valve
which may be utilized in the system of Figure 1.
Figure 3 is a graph showing the interrelationship
of vacuum developed in the output tube of a vortex
valve and the supply pressure to the valve.
Figure 4 is a graph illustrating a particular
curve of pressure required to produce a particular
quantity of flow in a system with which the present
invention is concerned.
Figure 5 is a side view in elevation illustra-
ting the interrelationship between the vortex chamber,
the output tube and the pressure sensing tube of
the apparatus of Figure 2 of the accompanying drawings.
Figure 6 is a simplified diagrammatic view
of a second embodiment of the present invention.
Figure 7 is a graph illustrating the variation
of flow through a vortex valve as a function of the
ratio of the input diameter of the vortex chamber
to the effective output diamet~r of the output passage.
Figure ~ is a plan view of a vortex valve
which may be utilized with the embodiment of Figure
6 of the accompanying drawings.
lZ07590
Figuxe 9 is a simplified diagrammatic view
of a further basic embodiment of the present invention.
Figure 10 is a front diagrammatic view of
the vortex chamber and the surrounding passageway
employed in Figure 9.
Figure 11 is a detailed view of one form of
the interaction region of the device of Figure 10.
Figure 12 is a detailed view of another form
of the interaction region of the device of Figure 10.
Figure 13 is a graph illustrating the flow
of liquid between compartments as a function of liquid
head for the interaction region of Figures 11 and 12.
~L207590
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Description of Preferred Embodiments
Referring now specifically to Figure 1 of
the accompanying drawings, there is illustrated a
gas tank 1 having a vertical indentation 2 in its
bottom surface to accommodate a tail pipe or exhaust
pipe 3 of the vehicle. It can be seen that below
the level of the maximum height of the indentation
2, which level is designated by the reference numeral 4,
the gas tank is divided into a left and a right compart-
ment. In systems which utilize throttle body injectorsand in some systems which utili~e carburetors and
diesel injectors, it is becoming common to increase
fuel efficiency by employing a sump-type pump 6 for
pumping fluid out of the gas tank 1 and to the general
vicinity of the engine.
Sump pumps as indicated previously are situated
in the liquid and do not have an appreciable negative
pressure or, in fact, a readily measurable negative
pressure. Also, it is important, due to considerations
of uitilization of energy, cost and size of the pump,
and related economic and efficiency factors, that
as little interference with the flow from the pump 6
be encountered in attempting to move fluid from the
right compartment of the tank to the left compartment
of the tank. Further, due to the environment in
whi~h this sytem is operating and the inaccessibility
120759~
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o~ the interior of the gas tank, it is important
that moving parts not be utilized to initiate siphoning
of fluid from the right compartment to the left compart-
ment.
In accordance with one embodiment of the
present invention, the siphoning is accomplished
by means of a siphon tube 8 which extends over the
vertical obstacle 10 of the tank and into the right
and left compartments as viewed in Figure 1 herein.
Since there is effectively no negative pressure at
the inlet side of the pump 6, it is not possible
to utilize the pump directly to suck on the left
- end of the suction tube 8 to thereby initiate a siphoning
action. The present invention, instead of sucking
on the end of the tube, creates suction at the vertical
apex of the tube 8 to draw liquid from both compartments
of the tank 1 to the maximum height of the siphon
tube 8 or even higher. Thus, when the fluid in the
left compartment falls below the level 4, that is,
below the level of the fluid in the right compartment,
the siphoning action is initiated and the right compart-
ment is drained concurrently with the left compart~ent.
The suction at the top of the pipe 8 is applied
via a suction tube 12 which is connected to sense
the negative pressure in the outlet passage of a
vortex valve or am~lifier 14. In Pigure 1, the vortex
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- 14 -
amplifier is connected in series between the pump
- 6 and outlet conduit 16 which conveys or conducts
fluid to the throt~le body injector or the carburetor
or the injectors of a diesel engine.
The configuration of the vortex valve which
may be utilized in the series arrangement illustrated
in Figure 1 of the accompanying drawings, is illustrated
in Figures 2 and 3. Fluid which is pumped into a
conduit 18 by the pump 6 is introduced via an inlet
passage 20 of the vortex valve and applied tangentially
to a circular chamber 32 of the valve via a passage
24 extending between the passage 20 and the cha~ber 22.
The suction line 12 is situated in the outlet passage
26 preferably in a position of maximum negative static
pressure developed in the outlet passage.
In accordance with standard vortex theory,
the fluid flowing through the passage 24 enters the
chamber 22 tangentially and swirls in an ever radially
decreasing vortical or helical pattern and enters
the outlet passage 26 at a greatly reduced static
pressure and develops a negative static pressure
internally of the passage. The dynamic pressure
of the fluid, of course, is very high at this point
due to the very rapid rotation of the fluid in its
transfer from the circumference of the chamber to
the small outlet passage.
1X07590
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In the configuration illustrated in Figure 2, islands
28 and 30 are introduced to partially reduce th~ vorticity
in the chamber to thereby reduce the pressure drop in the
apparatus. As previously indicated, in a system such as
that of the present invention, it is important for the
sake of economics and efficiency to utilize as small an
amount of energy as possible in driving the pump 6. Thus,
as little pressure drop above that required to initiate
siphoning should be an end goal.
In this context, reference is made now to the graph
of Figure 3 which plots vacuum against supply pressure
in a typical vortex valve. It will be noted that the four
inches which in the particular application for which the
invention was developed is essential, was achieved with
an available vortex valve with a supply pressure to the
valve of only 4.6 psi. Lower pressure drops may be achieved.
Thus, very great ~orticity is not required in the apparatus
when a vortex valve is utilized in series between the pump
6 and the outlet conduit 16. The siphon system must, of
course, be designed with the flow characteristics of the
total system in mind.
Reference is now made to Figure 4 of the accompany-
ing drawings which illustrates a typical Pressure versus
Quantity of flow curve, for a two-stage turbine pump such
as that employed in a throttle body injector system. Reference~
to Figure 4 indicates that a desired flow of 210 pounds
1207590
of fuel per hour is achieved with a pressure of 10 psi.
If a 4.6 psi drop in line pressure, or even smaller, is
achieved, then a total pressure from the pump of only 15
psi or less is required to achieve the desired flow to
the engine.
By utiliziny the quasi flow straighteners 28 and
30 in Figure 2, the degree of vorticity of the valve of
Figure 2 is controlled to provide the desired pressure
drop. It should be noted again that the vorticity of the
fluid and the pressure drop across the valve is also a
function of the relative diameters of the chamber 22 and
the effective diameter of the outlet passage 26 taking
into account the reduction in cross-sectional area of the
tube 26 resulting from the introduction of the pipe 12
therein. In any event, the overall configuration must
be such as to minimize the pressure drop across the valve;
4.6 psi or less in a properly designed system (which-con-
sideration eliminates the use of venturis). Thus, referring
again to Figure 4, the 10 pSl pressure required to obtain
210 pounds per hour of flow under these circumstances may
readily be achieved with a supply of pressure of less than
15 psi.
~ eferring now specifically to Figure 5 of the
accompanying drawings, the arrangement of the outlet pipe
26 and the vacuum tube pipe 12 is more fully illustrated.
....
~207590
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The inlet passage 24 is also shown but the islands 28 to
30 have been eliminated for the purposes of clarity. For
ease in mechanical assembly, the suction tube 12 enters
the outlet tube 26 through the opposite wall of the chamber
so that no obstruction is introduced into the passage 26
in bringing the tube 12 out through a side wall.
Referring now specifically to Figure 6 of the
accompanying drawings, there i5 illustrated an arrangement
for utilizing what might be called a shunt to sump arrange-
ment wherein the vortex valve is not in series with thepump 6 but taps off a portion of the fluid directed to the
conduit 16 and utilizes this diverted fluid for the operation
of the vortex valve and the development of the necessary
negative pressure or partial vacuum in the line 12. In
this instance, a tap-off pipe 32 supplies fluid to a vortex
valve 34, the output of which is returned via output passage
36 of the vortex valve 34 to the tank 1. In this embodi~
ment in order to minimize the amount of fluid that must
be bled from the line 16, a maximum pressure drop is developed
across the vortex valve. An advantage of this arrangement
is that clogging of the vortex valve does not impede flow
to the injector.
Reference is now made to Figure 7 which is a plot
of flow as a function of ratio of the inlet radius of the
vortex chamber to the effective radius of the output pipe.
It will be noted that, as the ratio increases, the flow
~2075g~
- 18
through the vortex valve decreases rapidly but the curve
displays a knee at about a ratio of 4 to 1. Although the
flow thereafter continues to decrease, it decreases at a
much less rapid rate. An input to output radius ratio of
4 to 1 may be utilized in the configuration of Figure 6
thereby achieving a relatively small body size.
A suitable vortex valve for such a use is illustrated
in Figure 8 in which the line 32 is introduced tangentially
into a chamber 38 having an inner or annular wall 40 disposed
therein and spaced inwardly therefrom to define a passage
between the annulus 40 and the outer wall of the chamber
38. The wall 40 is provided with two passages 42 and 44
(or other suitable number of passages) which extend through
the wall and into an inner chamber 46 defined by the wall
40 generally tangentially thereto. Output pipe 36 is disposed
coaxially with the wall 40 and sensing tube 12 is located
within the tube 36. The ratio of the outer wall or the
inner surface of the annular wall ~0 to the effective radius
of the output pipe, that is, the radius taking into account
the fact that pipe 12 is disclosed therein, is at least
4 to 1, thereby maximizing the pressure drop across the
appara~us. In the configuration of the apparatus of Figure
8, vacuums of lS psi and greater have been readily achieved
which are obviously more than ample to raise the liquid
into siphon 8 by far greater than the necessary four inches.
;
1207590
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The choice of the series or shunt to sump embodi-
ments of Figure 1 or Figure 6, respectively, in a parti-
cular system will be determined by many factors which
are beyond the control of the designer of the vortex
amplifier; specifically, the flow requirements of a
particular system, the efficiency of the pump, whether
the pump can be readily designed to or has excess pressure
or excess flow. If excess pressure is available, then
a series valve will be utilized. If excess flow is
available, then a shunt to sump valve will be employed.
These facts are readily apparent by reference to Figures 3
and 8 which show respectively the vortex valve performance
curve achieving the necessary four inches suction with
a pressure thereacross of 4.6 psi whereas the large
reduction in flow achieved on a 4 to 1 input to output
radius ratio discloses the low requirements for diversion
of fuel for use with a system with excess fuel flow
capacity.
In the arrangements thus far described, the
vortex valves are employed to raise the level of liquid
in a siphon tube to the maximum height of the tube,
thus permitting siphoning of fluid from either chamber
to the other depending upon in which compartment the
level of liquid is the highest. In both systems, the
serial and dump to sump systems, unassisted siphoning
is employed.
1207590
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In two further embodiments of the invention,
the vortex valve is employed as an active element, or
amplifier,in series in the siphoning system. Referring
specifically to Figure 9 of the accompanying drawing,
the gas tank 1 again has the sump pump 6 located therein
and conduit 16 for carrying fuel from the tank to the
engine, not illustrated. A portion of the liquid delivered
to conduit 16 is bled off through conduit 32 to vortex
valve 50. The valve 50 is located in the siphon tube;
in the illustration constituting two lengths of tubing
52 and 54 extending in to the left and right compartment
respectlvely of the tank 1.
The vortex unit 50 of Figure 9 consists of a
hollow flat cylindrical vortex chamber 56 (see Figure 10)
having tangential inlet passages 58 and a coaxial outlet
passage 60. The vortex chamber and outlet is surrounded
by a hollow flat cylindrical outer chamber 62 having
coaxial inlet and outlet passages 64 and 66 connected
to siphon tubes 52 and 54 respectively. The size or the passages
between the cylinders 56 and 62 are not çritical except
that the passages must be large enough to permit the
required rate of flow between chambers while at the
same time establishing rapid enough flow to clear out
vapor bubbles. The important configurations and dimensions;
however, relate to the region of interaction between
the flow through tube 60 and the flow between the two
chambers 56 and 62.
~20~ss~
- 21 -
Initially reference is made to Figure 13 of
the accompanying drawings which is a plot of quantity
of flow, Q, as a function of head, H, between the two
chambers.
In a "pump" configuration, flow, as indicated
by Graph A, is predominately from the right compartment
to the left or sump pump containing compartment. The
head, H, is positive if the level of fluid in the right
compartment is higher than in the left compartment.
The graph shows that the vortex pump continues to move
fluid to the left compartment even though it is at a
higher level than the right compartment and only stops
such pumping when the head is negative by a predetermined
design value.
The negative segment of curve A indicates
the obvious, if the head in the left compartment is
greater than that which can be developed by the vortex
pump, the pump is overwhelmed and fluid flows backwards;
i.e. to the right compartment. If only the pumping
action is desired, the head necessary to produce this
latter effect is greater than that which can be produced
as a result of the barrier between compartments and
as a practical matter cannot be achieved.
In a "siphon" configuration, the liquid, as
indicated by Graph B, flows in both directions; the
direction of flow being determined by whether the head, H,
1207590
- 2~ -
is positive or negative. As indicated previously, such
an arrangement is desired so that only one sender is
required for the fuel gauge.
The dashed line, Graph Bl, indicates a siphon
having a grèater hysteresis than Graph B; specifically,
the head required to initiate flow in either direction
is greater than in the Graph B configuration. As indicated
subsequently, the hysteresis is a function of the relative
dimensions and locations of the passages 60 and 64 and
reference is now made to Figure 11 of the accompanying
drawings.
In the configuration of Figure 11, the following
dimensions were employed in successful tests:
~ = 41
d1 = .048" - .052"
d2 = .15"
d3 = .43"- .44"
X = 025"- 05"
d4 (Fig. 10) = 0.31"
The value of ~ is not critical, 41~ being exemplary.
As to diameters dl - d4, the relative values are
of more importance than the absolute values. As to
dimension d3,as the ratio of d3/d2 gets smaller and/or
the overlap X1 increases, in other words, the volume of
the passage between the walls o~ the outlet 60 and the
~Z07590
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pipe 64 decreases, the device increasingly exhibits
the characteristics of Graph A of Figure 13; the pump
characteristics. Initially the curve B is increased
in slope and the hysteresis increases, See Graph Bl,
until eventually Graph A is approximated. Conversely,
as the ratio d3/d2 and/or the value of X increases,
the Curve B is approached, but the device cannot achieve
the function of a perfect siphon, i.e. a curve that passes
-
through the origin with no hysteresis.
It should be noted that the Graph A and the
other graphs are asymmetrical with respect to the origin;
the preferred direction of movement being in the direction
of flow out of the tube 60.
The configuration of Figure 11 makes a good
siphon but a less desirable pump. Specifically, to
obtain a good pump, there must be close coupling between
the flow from the tube 60 and the liquid in region 66.
I Due, however, to the thickness of the wall of the outlet
; 60, the liquid flow out of passage 60j as defined by
dashed line 68, is remote from the region 66. Thus,
the suction effect is not strong and pumping is not
efficient. On the other hand, siphoning requires less
direct coupling between the region 66 and the flow from
the tube 60, thereby permitting reversal of flow; specifically,
flow is more dependent on head, H, than in the case
of close coupling.
120759~
- 24 -
Reference is now made to Figure 12 of the accompany-
ing drawings wherein the dimensions of Figure 11 apply
except as indicated below:
Pump = .37-.39
Siphon = .44-.48
In this embodiment of the invention, the outer
wall or surface 70 of the outlet 60 is tapered whereby
by controlling the angle e, and/or the diameter d3 and~or
the diimension Xl, the coupling between the flow from
outlet 60 and region 66 may be readily determined and
pump or siphon operation determined. As previously
indicated and as brought out by the dimensions of d3,
above, with all other dimensions being the same as in
Figure 11, pump operation is achieved with close coupling,
d3=.37-.39, and excellent siphon operation is achieved with
; looser coupling, d3=.48 etc.
The present invention has been described for
utilization in a particular environment. However, it
is apparent that this sytem may be utilized wherever
the problems discussed herein are encountered.
Once given the above disclosure, other features,
modifications, and improvements will become apparent
to one skilled in the art. Such other modifications,
features and improvements are, therefore, considered
a part of this invention, the scope of which is to be
determined by the following claims.
