Abstrict A lower cost turbine flow meter comprised of an inner housing constructed
out of a high permeable material surrounded by an outer housing
constructed out of a lower cost, lower permeable material. A port
is placed in the outer housing that runs down to the surface of
the inner housing to detect the rotation of turbine rotors that
rotate inside the meter as fluid or gas flows through the meter.
A pickoff coil is placed in the port to generate a magnetic signal
to penetrate through the inner housing wherein the turbine rotor
vanes superimpose a pulse signal on the magnetic signal. The lower
cost turbine flow meter can be used for any application for measuring
fluid or gas, and may be used in a service station environment for
measuring fuel or vapor in vapor recovery applications.
Claims What is claimed is:
1. A turbine flow meter that measures the flow of a material, comprising:
an outer housing comprised of a low permeable material forming an
inlet port on one end of said outer housing and an outlet port on
the other end of said outer housing; a shaft supported inside said
outer housing along an axis parallel to said outer housing; a turbine
rotor mounted on said shaft, wherein said turbine rotor rotates
when the material flows through said inlet port; an orifice contained
in said outer housing that forms a first pickup port wherein a first
end of said orifice extends outward to the outer surface of said
outer housing, and said second end of said orifice extends down
to a higher permeable inner housing proximate to said turbine rotor;
and a first pickup coil that is mounted within said first pickup
port and excited by a signal received through said inner housing
from said turbine rotor as said turbine rotor rotates.
2. The meter of claim 1 further comprising a second turbine rotor
mounted on said shaft that rotates oppositely from said turbine
rotor.
3. The meter of claim 1 wherein said inner housing is made from
a material comprised from the group consisting of monel, a nickel-copper
alloy, steel, stainless steel, and 400-series non-magnetic stainless
steel.
4. The meter of claim 1 wherein said outer housing is made from
a material comprised from the group consisting of aluminum, plastic,
ceramic, ferrous metal, and non-ferrous metal.
5. The meter of claim 1 wherein said turbine rotor contains a
plurality of vanes that cause said turbine rotor to rotate when
said material comes into contact with said plurality of vanes.
6. The meter of claim 1 wherein said material is comprised from
the group consisting of a liquid and a gas.
7. The meter of claim 1 further comprising: a second orifice contained
in said outer housing that forms a second pickup port wherein a
first end of said second orifice extends outward to the outer surface
of said outer housing, and said second end of said second orifice
extends down to a higher permeable inner housing proximate to said
turbine rotor; and a second pickup coil that is mounted within said
second pickup port and excited by a signal received through said
inner housing from said turbine rotor as said turbine rotor rotates.
8. The meter of claim 1 wherein said inner housing is comprised
of a plug that is substantially the same size in diameter as said
orifice.
9. The meter of claim 1 wherein said inner housing is comprised
of a cylindrical-shaped material that is placed in between said
shaft and said outer housing.
10. A fuel dispenser for dispensing fuel to a vehicle, comprising:
a nozzle; a hose connected to said nozzle; a control system; a fuel
delivery line having an inlet port that receives fuel, and an outlet
port that couples to said hose; a valve located inline said fuel
delivery line and under control of said control system, wherein
said control system opens said valve to allow fuel to flow through
said fuel delivery line to be delivered through said hose and said
nozzle to the vehicle; and a turbine meter located inline said fuel
delivery line, comprising: an outer housing comprised of a low permeable
material forming an inlet port on one end of said outer housing
and an outlet port on the other end of said outer housing; a shaft
supported inside said outer housing along an axis parallel to said
outer housing; a turbine rotor mounted on said shaft, wherein said
turbine rotor rotates when the material flows through said inlet
port; an orifice contained in said outer housing that forms a first
pickup port wherein a first end of said orifice extends outward
to the outer surface of said outer housing, and said second end
of said orifice extends down to a higher permeable inner housing
proximate to said turbine rotor; and a first pickup coil that is
mounted within said first pickup port and excited by a signal received
through said inner housing from said turbine rotor as said turbine
rotor rotates; said turbine meter measures the amount of fuel traveling
through said fuel delivery line and sends a signal indicated of
the amount of fuel to said control system.
11. The fuel dispenser of claim 10 wherein said turbine meter
further comprises a second turbine rotor mounted on said shaft that
rotates oppositely from said turbine rotor.
12. The fuel dispenser of claim 10 wherein said turbine rotor
contains a plurality of vanes that cause said turbine rotor to rotate
when said material comes into contact with said plurality of vanes.
13. The fuel dispenser of claim 10 wherein said turbine meter
further comprises: a second orifice contained in said outer housing
that forms a second pickup port wherein a first end of said second
orifice extends outward to the outer surface of said outer housing,
and said second end of said second orifice extends down to a higher
permeable inner housing proximate to said turbine rotor; and a second
pickup coil that is mounted within said second pickup port and excited
by a signal received through said inner housing from said turbine
rotor as said turbine rotor rotates.
14. The fuel dispenser of claim 10 wherein said inner housing
is comprised of a plug that is substantially the same size in diameter
as said orifice.
15. The fuel dispenser of claim 10 wherein said inner housing
is comprised of a cylindrical-shaped material that is placed in
between said shaft and said outer housing.
16. The fuel dispenser of claim 10 further comprising a totals
display that displays the total amount of fuel metered through said
turbine meter.
17. A vapor recovery system, comprising: an underground storage
tank that contains fuel and vapor; a vent coupled to said underground
storage tank; a membrane coupled inline to said vent that receives
said vapor from said underground storage tank and substantially
separates said vapor into a hydrocarbon mixture and an air mixture;
a pressure valve coupled inline to said vent downstream of said
membrane wherein said pressure valve is opened to release said air
mixture to atmosphere when said underground storage tank is under
a threshold pressure and said hydrocarbon mixture is returned back
to said underground storage tank; and a turbine flow meter that
measures the amount of air being released to atmosphere, comprising:
an outer housing comprised of a low permeable material forming an
inlet port on one end of said outer housing and an outlet port on
the other end of said outer housing; a shaft supported inside said
outer housing along an axis parallel to said outer housing; a turbine
rotor mounted on said shaft, wherein said turbine rotor rotates
when said material flows through said inlet port; an orifice contained
in said outer housing that forms a first pickup port wherein a first
end of said orifice extends outward to the outer surface of said
outer housing, and said second end of said orifice extends down
to a higher permeable inner housing proximate to said turbine rotor;
and a first pickup coil that is mounted within said first pickup
port and excited by a signal received through said inner housing
from said turbine rotor as said turbine rotor rotates; said turbine
meter measures the amount of air mixture traveling through said
vent.
18. The system of claim 17 wherein said turbine meter further
comprises a second turbine rotor mounted on said shaft that rotates
oppositely from said turbine rotor.
19. The system of claim 17 wherein said turbine rotor contains
a plurality of vanes that cause said turbine rotor to rotate when
said material comes into contact with said plurality of vanes.
20. The system of claim 17 wherein said turbine meter further
comprises: a second orifice contained in said outer housing that
forms a second pickup port wherein a first end of said second orifice
extends outward to the outer surface of said outer housing, and
said second end of said second orifice extends down to a higher
permeable inner housing proximate to said turbine rotor; and a second
pickup coil that is mounted within said second pickup port and excited
by a signal received through said inner housing from said turbine
rotor as said turbine rotor rotates.
21. The system of claim 17 wherein said inner housing is comprised
of a plug that is substantially the same size in diameter as said
orifice.
22. The system of claim 17 wherein said inner housing is comprised
of a cylindrical-shaped material that is placed in between said
shaft and said outer housing.
23. The system of claim 17 wherein said first pickup coil generates
a signal indicative of the amount of air mixture and communicates
said signal to a site controller.
24. A vapor recovery system that captures vapors expelled from
a vehicle during refueling and returns the vapors to an underground
storage tank, comprising: a fuel dispenser comprising a control
system and a vapor recovery system that captures vapors expelled
from the vehicle during refueling and returns the vapors through
a vapor return line to the underground storage tank; a turbine flow
meter coupled inline to said vapor return line that measures the
amount of vapors being returned to the underground storage tank
wherein said control system adjusts said vapor recovery system to
vary the rate of recovery of the vapors based on the measurement
of the amount of vapors being returned to the underground storage
tank, said turbine flow meter comprising: an outer housing comprised
of a low permeable material forming an inlet port on one end of
said outer housing and an outlet port on the other end of said outer
housing; a shaft supported inside said outer housing along an axis
parallel to said outer housing; a turbine rotor mounted on said
shaft, wherein said turbine rotor rotates when the material flows
through said inlet port; an orifice contained in said outer housing
that forms a first pickup port wherein a first end of said orifice
extends outward to the outer surface of said outer housing, and
a second end of said orifice extends down to a higher permeable
inner housing proximate to said turbine rotor; and a first pickup
coil that is mounted within said first pickup port and excited by
a signal received through said inner housing from said turbine rotor
as said turbine rotor rotates; said first pickup coil generates
a signal indicative of the amount of vapors passing through said
turbine meter.
25. The vapor recovery system of claim 24 wherein said turbine
meter further comprises a second turbine rotor mounted on said shaft
that rotates oppositely from said turbine rotor.
26. The vapor recovery system of claim 24 wherein said turbine
rotor contains a plurality of vanes that cause said turbine rotor
to rotate when said material comes into contact with said plurality
of vanes.
27. The vapor recovery system of claim 24 wherein said turbine
meter further comprises: a second orifice contained in said outer
housing that forms a second pickup port wherein a first end of said
second orifice extends outward to the outer surface of said outer
housing, and said second end of said second orifice extends down
to a higher permeable inner housing proximate to said turbine rotor;
and a second pickup coil that is mounted within said second pickup
port and excited by a signal received through said inner housing
from said turbine rotor as said turbine rotor rotates.
28. The vapor recovery system of claim 24 wherein said inner housing
is comprised of a plug that is substantially the same size in diameter
as said orifice.
29. The vapor recovery system of claim 24 wherein said inner housing
is comprised of a cylindrical-shaped material that is placed in
between said shaft and said outer housing.
30. The vapor recovery system of claim 24 wherein said signal
indicative of the amount of vapor passing through said turbine meter
is communicated to a site controller.
31. The vapor recovery system of claim 24 wherein said control
system divides the amount of vapor by the amount of fuel dispensed
by said fuel dispenser to determine a vapor-to-liquid (V/L) ratio.
32. The vapor recovery system of claim 31 wherein said control
system adjusts said vapor recovery system in order to maintain a
desired V/L ratio.
33. A method of measuring the flow rate of a material, comprising
the steps of: passing a material through an inlet port of an inner
housing comprised of a high permeable material; rotating a turbine
rotor mounted inside said inner housing as said materials passes
through said inner housing; receiving a signal from a first pickup
coil mounted on said inner housing proximate to said turbine rotor
and within a first pickup port in an outer housing of a low permeable
material formed around said inner housing to detect rotation of
said turbine rotor; and correlating the rotation of said turbine
rotor into a flow rate of said material.
34. The method of claim 33 further comprising the steps of: receiving
a second signal from a second pickup coil offset from said first
pickup coil and mounted on said inner housing proximate to said
turbine rotor and within a second pickup port in said outer housing
to detect rotation of said turbine rotor; and determining the direction
of rotation of said turbine meter based on said signal and said
second signal.
35. A method of manufacturing a turbine flow meter, comprising
the steps of: forming an outer housing constructed of a low permeable
material; placing a turbine rotor on a shaft; placing said shaft
inside said outer housing on an axis in parallel with said outer
housing; placing an orifice in said outer housing that forms a first
pickup port wherein a first end of said orifice extends outward
to the outer surface of said outer housing, and said second end
of said orifice extends down to a higher permeable inner housing
placed proximate to said turbine rotor; and placing said first pickup
port in said outer housing proximate to the location of said turbine
rotor that runs down to the outer surface of said inner housing.
36. The method of claim 35 further comprising the steps of: placing
a second pickup port in said outer housing offset from said first
pickup port and located proximate to the location of said turbine
rotor that runs down to the outer surface of said inner housing;
and mounting a second pickup coil inside said second pickup port
on said inner housing.
Description FIELD OF THE INVENTION
[0001] The present invention relates to a turbine flow meter design
for measurement of liquid or gaseous materials that yields increased
sensitivity for turbine rotor pickup with a lower production cost.
BACKGROUND OF THE INVENTION
[0002] Flow meters are used for a variety of applications where
it is desired to measure the flow rate or volume of a given fluid
or gaseous material. Some meters are inferential meters, meaning
that the actual displacement of the liquid or gaseous material is
not measured. An inferential meter uses some other characteristic
other than actual displacement to measure flow rate or volume. Inferential
meters sometimes have advantages over positive displacement meters,
including smaller size. However, inferential meters are also sometimes
more costly than positive displacement meters since inferential
meters often include more complex designs and require supporting
electronics to properly operate. Therefore, it may be important
to find methods of reducing the cost of an inferential meter so
that the cost of using an inferential meter versus a positive displacement
meter is minimized if not eliminated.
[0003] One example of an inferential meter is known as a turbine
flow meter, like that described in U.S. Pat. No. 5689071. The
turbine flow meter described in this patent measures the flow rate
of a fluid or gaseous material by determining the number of rotations
of a turbine rotor located inside the flow path of the meter. The
meter is comprised of a hollow housing that includes a turbine rotor
on a shaft inside the flow path created by the housing. The housing
is constructed out of a high permeable material, such as stainless
steel.
[0004] As material enters the inlet port of the meter, the material
passes through the turbine rotors causing the turbine rotors to
rotate at a rate that depends on the flow rate of the material passing
through the housing. The rotational velocity of the turbine rotor
is sensed by a pickoff coil. The pickoff coil is excited by an a-c
signal that produces a magnetic field. As the turbine rotor rotates,
the vanes on the turbine rotor pass through the magnetic field generated
by the pickoff coil, superimposing a pulse upon the carrier waveform
of the pickoff coil. The superimposed pulses occur at a repetition
rate (pulses per second) proportional to rotor velocity and hence
proportional to the measured rate of fluid flow.
[0005] The pickoff coil is countersunk in a port that is drilled
into the housing, but the pickoff coil does not reach the inner
portion of the housing. Since the housing is constructed out of
a high permeable material, the signal generated by the pickoff coil
penetrates the housing to reach the vanes of the turbine rotor and
superimposed pulses are detectable by the pickoff coil through the
housing as well. One method to reduce the cost of this turbine flow
meter is to use a lower cost housing material since the housing
material comprises a large majority of the material used in the
turbine flow meter. However, less costly materials, such as aluminum
for example, have a low permeability thereby making it difficult
or impossible for the pickoff coil to detect the rotation of the
turbine rotor inside the housing.
[0006] Therefore, it is desirable to find a technique to use a
lower cost, lower permeable material for the housing of the turbine
flow meter without disturbing the performance of the pickoff coil.
SUMMARY OF THE INVENTION
[0007] The present invention relates to a lower cost turbine flow
meter. The turbine flow meter is comprised of an outer housing constructed
out of a low permeable material forming an inlet port on one end
of the outer housing and an outlet port on the other end of the
outer housing. A shaft is supported inside the outer housing along
an axis parallel to the outer housing. A turbine rotor is mounted
on the shaft, wherein the turbine rotor rotates when the material
flows through the inlet port. An orifice is contained in the outer
housing that forms a first pickup port wherein a first end of the
orifice extends outward to the outer surface of the outer housing,
and the second end of the orifice extends down to a higher permeable
inner housing proximate to the turbine rotor. A first pickup coil
is mounted within the first pickup port and is excited by a signal
received through the inner housing from the turbine rotor as the
turbine rotor rotates when fluid passes through the meter.
[0008] The inner housing may be comprised of a hollow, cylindrical
shaped high permeable material that is placed between the shaft
and the outer housing such that the inner housing completely surrounds
the shaft and the turbine rotors. Or the inner housing may be a
plug of high permeable material that is placed inside an orifice
in the outer housing proximate to the turbine rotor in order to
conserve costs by providing low permeable material.
[0009] The turbine meter may contain more than one turbine rotor
and more than one pickoff port and coil so that a controller can
determine the ratio of the rotation speed of one turbine rotor to
the other to determine the flow rate of the fluid or gas flowing
through the turbine meter. Also, more than one pickoff port and
coil may be provided for a single turbine rotor so that the direction
of rotation of the turbine rotor can be detected to detect backflow
of gas or liquid in the turbine meter.
[0010] The turbine meter may be used in a fuel dispenser application.
The turbine meter may be used to measure fuel in a fuel dispenser,
the vapor being returned to the underground storage tank in a stage
two vapor recovery fuel dispenser, or vapor or air released to atmosphere
from the ullage area of an underground storage tank when a pressure
relief valve in a vent stack is opened on the underground storage
tank to relieve pressure.
[0011] The turbine meter data in a fueling environment may be used
to determine the vapor-to-liquid (V/L) ratio of a stage two vapor
recovery dispenser to adjust the vapor recovery system to operate
within desired V/L limits or to provide diagnostic data about measured
fuel, vapor and/or air to a site controller or tank monitor for
compliance monitoring and reporting.
[0012] Those skilled in the art will appreciate the scope of the
present invention and realize additional aspects thereof after reading
the following detailed description of the preferred embodiments
in association with the accompanying drawing figures.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] The accompanying drawing figures incorporated in and forming
a part of this specification illustrate several aspects of the invention,
and together with the description serve to explain the principles
of the invention.
[0014] FIG. 1A is a schematic diagram of the turbine flow meter
according to the present invention;
[0015] FIG. 1B illustrates a side view of FIG. 1A;
[0016] FIG. 2A is a schematic diagram of a turbine flow meter according
to an alternative embodiment of the present invention;
[0017] FIG. 2B illustrates a side view of FIG. 2A;
[0018] FIG. 3 is a schematic diagram of the turbine flow meter
according to the present invention used as a fuel metering device
in a fuel dispenser for fueling vehicles;
[0019] FIG. 4 is a schematic diagram of the turbine flow meter
used as a fugitive emission meter for an underground storage tank
in a service station environment;
[0020] FIG. 5 is a schematic diagram of the turbine flow meter
used as a vapor flow meter for adjusting the vapor recovery system
of a fuel dispenser;
[0021] FIG. 6 is a schematic diagram of the flowchart process of
adjusting the vapor recovery system of a fuel dispenser based on
use of the turbine meter as a vapor flow meter, as illustrated in
FIG. 5; and
[0022] FIG. 7 is a schematic diagram of a diagnostic reporting
architecture for the turbine flow meter.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0023] The embodiments set forth below represent the necessary
information to enable those skilled in the art to practice the invention
and illustrate the best mode of practicing the invention. Upon reading
the following description in light of the accompanying drawing figures,
those skilled in the art will understand the concepts of the invention
and will recognize applications of these concepts not particularly
addressed herein. It should be understood that these concepts and
applications fall within the scope of the disclosure and the accompanying
claims.
[0024] The present invention is related to a lower cost turbine
flow meter for measuring the flow rate and/or volume of a gas or
liquid. The flow meter is comprised of an inner housing constructed
out of a high permeable material surrounded by an outer housing
constructed out of a lower cost, lower permeable material. A port
is placed in the outer housing that runs down to the surface of
the inner housing to detect the rotation of turbine rotors that
rotate inside the fluid meter as fluid or gas flows through the
meter. Pickoff coils are placed in the port to generate a magnetic
signal to penetrate through the higher permeable inner housing wherein
the turbine rotor vanes superimpose a pulse signal on the magnetic
signal. This pulse signal is used to determine the flow rate and/or
volume of the fluid or gas passing through the flow meter. Because
the pickoff coil is placed at the surface of the higher permeable
inner housing material instead of the surface of the lower permeable
outer housing, detection of rotation of the turbine rotors is possible.
If the housing of the turbine flow meter was totally constructed
out of a high permeable material, and/or the pickoff coil was not
placed at the surface of a higher permeable material to allow a
magnetic signal generated by the pickoff coil to penetrate through
the housing to reach the turbine rotors, the turbine flow meter
would either not work correctly or be defective in its operation.
[0025] FIG. 1A illustrates a turbine flow meter 10 according to
the present invention. This turbine flow meter is like that described
in U.S. Pat. No. 5689071 entitled "Wide range, high accuracy
flow meter," incorporated herein by reference in its entirety.
The turbine flow meter 10 is comprised of an inner housing 12 that
is constructed out of a high permeable material, such as monel,
a nickel-copper alloy, steel, stainless steel, and 400-series non-magnetic
stainless steel, for example. The inner housing 12 is hollow and
forms an inlet port 14 and an outlet port 16 for fluid or gas to
enter into the flow meter 10 and to leave the flow meter 10 respectively.
A shaft 18 is placed internal to the internal housing 12 to support
one or more turbine rotors 20 21. The turbine rotor 20 may be also
called the "first turbine rotor," and the turbine rotor
21 may also be called the "second turbine rotor."
[0026] The turbine rotors 20 21 rotate in an axis perpendicular
to the axis of the shaft 18. The turbine rotors 20 21 contain one
or more vanes 22 23 also known as blades. As the fluid or gas
passes through the inlet port 14 and across the vanes 22 23 of
the turbine rotors 20 21 the turbine rotors 20 21 and vanes 22
23 rotate at a speed proportional to the rate of flow of the gas
or liquid flowing through the turbine flow meter 10. The proportion
of the rotational speed of one turbine rotor 20 to the other turbine
rotor 21 as determined by counting the vanes 22 23 passing by
the pickoff coils 29 30 to determine the flow rate of the fluid
or gas passing through the meter 10 as is described in U.S. Pat.
No. 5689071 previously referenced herein. It is noted that the
turbine flow meter 10 can be provided with only one turbine rotor
20 to detect flow rate as well. In the present invention, the inner
housing 12 is surrounded by an outer housing 24 constructed out
of a lower permeable material than the inner housing 12 including
but not limited to aluminum, plastic, ceramic, ferrous metal, and
non-ferrous metal. Lower permeable materials are typically cheaper
than higher permeable materials and therefore provide a lower cost
of manufacture. Since the housing structure of the turbine flow
meter 10 comprises a majority of the amount of raw material used
in constructing a turbine flow meter 10 all savings that can be
achieved by using a lower cost material to form the outer housing
24 will be a significant cost reduction in the overall cost of the
turbine flow meter 10.
[0027] FIG. 1B illustrates a side view of the turbine flow meter
10 illustrated in FIG. 1A. The shaft 18 and turbine rotors 20 21
with its vanes 22 23 located inside the inner housing 12 are illustrated.
The thickness of the inner housing 12 is much less than the thickness
of the outer housing 24; however, these thicknesses are a matter
of design choice and the present invention is not limited to any
particular thickness. What is important is that the outer housing
24 be constructed of a lower cost material and of a less permeable
material than the inner housing 12.
[0028] In order to detect the rotation of the turbine flow meter
10 to then derive the flow rate or volume of the fluid flowing through
the turbine flow meter 10 one or more pickup ports 26 28 are drilled
into the outer housing 24 during the manufacture of the meter 10
so that the ports 26 28 extend all the way to the surface area
of the inner housing 12. The port 26 may be called the "first
port," and the port 28 may be called the "second port."
The ports 26 28 allow the pickoff coils 29 30 to be placed inside
each of the ports 26 28 at the surface area of the inner housing
12. The pickoff coils 29 30 may be like those described in U.S.
Pat. No. 5689071 previously referenced.
[0029] The pickoff coils 29 30 generate a magnetic signal that
penetrates through the higher permeable inner housing 12 to reach
the turbine rotors 20 21. As the turbine rotors 20 21 rotate,
the vanes 22 23 superimpose a pulse signal on the magnetic signal
generated by the pickoff coils 29 30. This pulse signal can be
later analyzed by a microprocessor or other control system (not
shown) to determine the rate of pulses that correlates to the volume
or flow rate of the fluid or gas flowing through the turbine flow
meter 10.
[0030] In the embodiment illustrated in FIGS. 1A and 1B, two ports
26 28 are provided for two pickoff coils 29 30 to be used. However,
it is noted that an alternative embodiment of the present invention
only involves use of one turbine rotor 20 with one port and one
pickup coil since the flow rate of the fluid or gas passing through
the meter 10 can be measured by just using the rotation speed of
one turbine rotor.
[0031] In yet another variation of the present invention, another
port 32 and pickoff coil 31 may be provided, as illustrated in FIGS.
1A and 1B. This additional port 32 is placed in proximity to the
turbine rotor 21 so that the turbine rotor 21 has two ports and
two pickoff coils 30 31. Use of two pickoff coils 30 31 via ports
28 32 on one turbine rotor 21 allows detection of direction of
rotation of the turbine rotor 21 as well as the speed. If the turbine
rotor 21 is rotating in a direction opposite from a normal direction,
this indicates that a backflow of gas or liquid is passing back
through the meter 10. In this event, the measured backflow of gas
or liquid, as measured by the detection of the rotation of the vanes
22 23 on the turbine rotor 21 is subtracted from the total flow
rate or volume of the gas or liquid passing through the meter 10
to arrive at an accurate measurement. It should be noted that port
32 may be provided with either turbine rotor 20 21.
[0032] FIGS. 2A and 2B (a side view of FIG. 2A) illustrate another
embodiment of the turbine flow meter 10 that may be used with the
present invention. In FIGS. 2A and 2B, the body of the turbine flow
meter 10 only includes a single outer housing 24 comprised of a
lower permeable material. The ports 26 28 and port 32 if provided,
are formed by holes drilled all the way through the outer housing
24 such that the ports 26 28 32 (if provided) form an orifice
from the outer surface of the outer housing 24 all the way to the
inside of the flow meter 10 without interruption or blockage. Next,
plugs 33 34 35 constructed out of higher permeable material than
the outer housing 24 are placed inside the ports 26 28 32. One
end of the plugs 33 34 35 is substantially flush with the inside
of the inner housing 24 of the meter 10. The plugs 33 34 35 are
typically less in length that the length of the ports 26 28 32
so that pickoff coils 29 30 31 may still be placed inside the
ports 26 28 32 resting against or in close proximity to the other
end of the plugs 33 34 35. However, the plugs 33 34 35 could
extend out of the outer housing 24 if desired.
[0033] In this manner, the rotation of the vanes 22 23 will still
be detectable since the higher permeable plugs 33 34 35 are placed
in between the pickoff coils 29 30 31 and the vanes 22 23. This
allows even less of the higher cost, higher permeable material to
be used in the construction of the turbine meter 10 to yield even
a lower manufacturing cost. It should be noted that the embodiment
illustrated in FIGS. 2A and 2B may be provided with one port 26
two ports 26 28 or the three ports 26 28 30 as illustrated in
FIGS. 1A and 1B.
[0034] FIG. 3 illustrates use of the turbine flow meter 10 according
to the present invention in a fuel dispenser 40. The purpose of
a fuel dispenser 40 is to measure the amount of fuel being delivered
to a vehicle (not shown). Very accurate meters are required to measure
fuel dispensing to comply with Weights & Measures regulatory
requirements. The fuel dispenser 40 may be a blending type fuel
dispenser wherein a low-octane fuel 41 stored in a low-octane underground
storage tank 42 and a high-octane fuel 43 stored in a high-octane
underground storage tank 44 are blended together by the fuel dispenser
40 to deliver either a low-octane fuel 41 high-octane fuel 43
or a mixture of both to a vehicle. The low-octane fuel 41 is supplied
to the fuel dispenser 40 through a low-octane fuel supply conduit
46. Likewise, the high-octane fuel 43 is delivered to the fuel dispenser
40 through a high-octane fuel supply conduit 48. Both the low-octane
fuel 41 and the high-octane fuel 43 pass through the fuel dispenser
40 in their own independent flow paths. Each fuel 41 43 encounters
a valve 50 52 that controls whether the fuel is allowed to enter
into the fuel dispenser 40 and if so at what flow rate. Valves
50 52 may be proportionally controlled and are under the control
of a controller 60 in the fuel dispenser 40.
[0035] The controller 60 determines when a fueling operation is
allowed to begin. Typically, a customer is required to push a start
button 78 to indicate which octane of fuel 41 43 is desired, and
the controller 60 thereafter controls the valves 50 52 to allow
the low-octane fuel 41 or the high-octane fuel 43 to be dispensed,
depending on the type of octane of fuel selected by the customer.
After the fuel 41 43 passes through both the valves 50 52 (if
a blended octane fuel was selected by the customer), the fuels 41
43 flow through turbine flow meters 10A, 10B according to the present
invention. If only a low-octane fuel 41 or high-octane fuel 43 was
selected by the customer to be dispensed, the controller 60 would
only open one of the valves 50 52. As the fuels 41 43 flow through
the turbine flow meters 10A, 10B, pickoff coils 29 30 (not shown)
on each of the turbine flow meters 10A, 10B produce a pulser signal
66 68 that is input into the controller 60. The controller 60 determines
the amount of flow of fuel flowing through turbine flow meters 10A,
10B for the purpose of determining the amount to charge a customer
for delivery of such fuel. The controller 60 uses the data from
the pulser signal 66 68 to generate a totals display 70.
[0036] The totals display 70 is comprised of an amount to be charged
to the customer display 72 the amount of gallons dispensed display
74 and the price per unit of fuel display 76. Also, U.S. Pat. No.
4876653 entitled "Programmable multiple blender" describes
a blender operation like that illustrated in FIG. 3 and is incorporated
herein by reference in its entirety. As either the low-octane fuel
41 high-octane fuel 43 or both pass through their respective turbine
flow meters 10A, 10B, the fuels come together in the blend manifold
54 to be delivered through the hose 56 and nozzle 58 into the vehicle.
[0037] FIG. 4 illustrates another application for use of the turbine
flow meter 10 in a service station environment. FIG. 4 illustrates
an underground storage tank pressure reduction system like that
described in U.S. Pat. No. 5464466 entitled "Fuel storage
tank vent filter system," incorporated herein by reference
in its entirety. The fuel dispenser 10 is a vapor recovery fuel
dispenser wherein vapor captured during refueling of a vehicle is
passed back to the ullage area 82 of an underground storage tank
42 44. The ullage area 82 of the underground storage tank 42 44
contains vapor 80. If the pressure inside underground storage tank
42 44 rises to a certain level, the membrane system 92 is activated
to separate the hydrocarbons from the vapor 80. As the hydrocarbons
are separated from the vapor 80 the hydrocarbons are returned to
the ullage area 82 of the underground storage tank 42 44 via a
vapor return line 96. The membrane 92 may either permeate hydrocarbons
or permeate oxygen or air as disclosed in U.S. Pat. Nos. 5464466
and 5985002 incorporated herein by reference in their entirety.
[0038] The air that is separated from a hydrocarbon in the vapor
80 is then released to atmosphere through a vent stack 90 and a
turbine flow meter 10. The amount of air is measured and then released
to atmosphere if there is sufficient pressure to release pressure
valve 94. It may be desirable to measure the amount of air flowing
through the vent stack 90 using the turbine flow meter 10 to determine
how often and how much air is separated by the membrane 92 and released
to atmosphere for any number of diagnostic or information purposes.
Because of the small size of the turbine flow meter 10 and other
diagnostic information it can provide, use of the turbine flow meter
10 in the vent stack 10 may be particularly useful.
[0039] FIG. 5 describes another application for use of the turbine
flow meter 10 wherein the turbine flow meter 10 measures the amount
of vapor 80 being returned to the underground storage tank 42 in
a stage two vapor recovery system. Fuel 41 is delivered from the
underground storage tank 42 via a fuel supply conduit 46 to the
fuel dispenser 40. As the fuel 41 enters the hose 56 and is delivered
to the vehicle 100 through a nozzle 58 the vapor 80 present in
the vehicle fuel tank 102 is displaced out of the vehicle 100. The
hose 56 and nozzle 58 are configured to provide a separate return
path known as a vapor return line 88 to allow vapor 80 to be captured
by the fuel dispenser 40. The vapor 80 is returned back to the underground
storage tank 42 through the vapor return line 88 into the ullage
area 82 of the underground storage tank 42.
[0040] As vapor 80 is passed through the vapor return line 88 in
the fuel dispenser 40 the vapor 80 passes through a turbine flow
meter 10. The turbine flow meter 10 measures the amount of vapor
flow being returned to the underground storage tank 42 for the purpose
of determining if the fuel dispenser 40 is recovering the correct
amount of vapor 80 in relation to the fuel 41 dispensed into the
vehicle 100. Since there is a relationship between the amount of
fuel 41 dispensed into the vehicle 100 and the amount of vapor 80
displaced from the vehicle fuel tank 102 a relationship can be
derived known as the "vapor to liquid ratio" (V/L ratio).
[0041] The controller 60 is configured to determine the V/L ratio
by calculating the V/L ratio as determined by the pulse signal from
the turbine flow meter 10 which may be called a vapor flow meter,
in the vapor return line 88 (numerator), and the pulse signal from
the turbine flow meter 10 that measures the amount of fuel 41 dispensed
into the vehicle 100 (denominator). FIG. 6 illustrates a flow chart
for one embodiment wherein a fuel dispenser 40 calculates the V/L
ratio and adjusts the fuel dispenser 40 vapor recovery system in
response.
[0042] The process starts (block 110), and the fuel dispenser 40
starts a vapor recovery pump 104 to create a vacuum in the vapor
return line 88 (block 112). As fuel 41 is dispensed into the vehicle
fuel tank 102 vapor 80 is returned in the vapor return line 88
and flows through the turbine flow meter 10. The pulser output from
the turbine flow meter 10 is communicatively coupled to a controller
60 in the fuel dispenser 40. The controller 60 measures the amount
of vapor flow in the vapor return line 88 being returned to the
underground storage tank 42 (block 114). The controller 60 then
divides the amount of vapor flow by the fuel flow rate to arrive
at a V/L ratio (block 116).
[0043] The controller 60 next determines if the V/L ratio is within
desired limits (decision 118). If the V/L ratio is within desired
limits, the process determines if fueling has been completed (decision
120). If so, the process ends (block 122). If not, the controller
60 continues to measure the vapor flow and calculate the V/L ratio
to determine if it is within desired limits (blocks 114 116 118).
If the V/L ratio was not within the desired limits (decision 118),
the controller 60 adjusts the vapor pump 104 and/or vapor recovery
system to adjust the V/L ratio to attempt to put it within desired
limits (block 124). This may be done by any number of methods, including
adjusting the speed of the vapor pump 104 or adjusting vapor valves
(not shown) that control the amount of vapor 80 being returned to
the underground storage tank 42. More information on stage two vapor
recovery systems for fuel dispensers may be found in patents Reissue
No. 35238 U.S. Pat. Nos. 6170539; 6336479; 6338369; and
6386246 all of which are incorporated herein by reference in
their entireties.
[0044] FIG. 7 illustrates a communication architecture whereby
flow data from the turbine flow meter is communicated to other systems.
As previously described, the flow data from the turbine flow meter
10 is communicated to the controller 60 for processing and measuring
purposes, including the applications previously described. The controller
60 may then pass the diagnostic information to a site controller/tank
monitor 130 over a local communication line 132 for purposes such
as diagnostics or any other application desired. The site controller/tank
monitor 130 may in turn pass such information regarding the turbine
flow meter 10 to a remote system 134 via a remote communication
line 136 for the same purpose. The controller 60 may also be configured
to communicate the flow data from the turbine flow meter 10 directly
to the remote system 134 via the remote communication line 136 rather
than through an intermediate site controller/tank monitor 130.
[0045] Those skilled in the art will recognize improvements and
modifications to the preferred embodiments of the present invention.
All such improvements and modifications are considered within the
scope of the concepts disclosed herein and the claims that follow. |