Abstrict A system for monitoring the volume rate of flow and total volume
of liquid being drawn from a supply by way of a plurality of discharge
conduits includes a flow meter transducer for associated individually
with each of the discharge conduits with the transducers providing
pulse information to associated flow meter circuits that are connected
in series relationship with one another and to a master control
module. Each of the individual flow meter circuits includes a pair
of microprocessors, one for determining from the pulse information
of its associated transducer the volume rate of flow of liquid out
its associated discharge conduit. The second microprocessor is programmed
to combine the flow information from its own transducer with combined
flow information from an adjacent upstream flow meter circuit in
the series string and produces a combined flow output signal for
delivery to an adjacent downstream flow meter circuit. In this fashion,
flow information associated with each of the discharge conduits
can be individually displayed with the total volume rate of flow
information being presented on a visual display associated with
the master controller.
Claims What is claimed is:
1. Apparatus for measuring and displaying volume rate of flow data
and total flow data of fluid being drawn from a plurality of discharge
conduits comprising:
(a) a plurality of flow meter circuits individually associated
with said plurality of discharge conduits, said plurality of flow
meter circuits being connected in series relation with each other;
(b) each flow meter circuit including:
(i) a flow transducer producing pulses at a frequency proportional
to a rate of flow of the fluid passing through an associated discharge
conduit,
(ii) a first microprocessor coupled to the flow transducer to receive
the pulses, said first microprocessor counting said pulses and converting
said pulses count into the volume rate of flow data and total flow
data,
(iii) a second microprocessor including a first input coupled to
a first output of the first microprocessor for receiving the volume
rate of flow data from an associated flow meter circuit, a second
input for receiving volume rate of flow data from an adjacent upstream
flow meter circuit in the series relation, said second microprocessor
programmed to compute a combined volume rate of flow value from
the adjacent upstream flow meter circuit and the associated flow
meter circuit, and an output coupled to an adjacent downstream flow
meter circuit in the series relation for delivering the combined
volume rate of flow value; and
(c) a visual display device coupled to a second output of the first
microprocessor for selectively providing a visual manifestation
of said volume rate of flow data and total flow data from the associated
discharge conduit.
2. A fluid handling system including at least one fluid supply
reservoir connected to a manifold, a plurality of fluid discharge
outlets in fluid communication with said manifold, a flow meter
system for measuring and displaying a volume rate of flow data and
total flow data of said fluid from each of said plurality of fluid
discharge outlets and for displaying a total flow and individual
flow of said fluid from said plurality of fluid discharge outlets,
said flow meter system comprising in combination:
(a) a plurality of flow meter circuits, each of said plurality
of flow meter circuits including.
(i) a flow responsive transducer producing output pulses at a rate
proportional to the volume rate of flow of said fluid across said
flow responsive transducer,
(ii) a first microprocessor coupled to said flow responsive transducer
to receive the output pulses, said first microprocessor programmed
for counting the output pulses and converting the output pulses
count into the volume rate of flow data and total flow data of said
fluid,
(iii) alpha/numeric display means coupled to the first microprocessor
for selectively displaying the volume rate of flow data and total
flow data of said fluid,
(iv) a second microprocessor coupled to the first microprocessor
for receiving the volume rate of flow data;
(b) said plurality of flow meter circuits being connected in a
serial string with a controller for selectively displaying the total
flow and individual flow of said fluid from said plurality of discharge
outlets;
(c) the second microprocessor in one of the flow meter circuits
receiving the volume rate of flow data from the first microprocessor
of same said one of the flow meter circuits and a volume rate of
flow data from a second microprocessor of an adjacent upstream one
of the flow meter circuits and programmed to compute a combined
volume rate of flow value from said adjacent upstream one of the
flow meter circuits and the same said one of the flow meter circuits;
and
(d) means for applying the combined volume rate of flow value from
said one of the flow meter circuits to a second microprocessor of
a downstream one of the flow meter circuits.
Description BACKGROUND OF THE INVENTION
I. Field of the Invention
This invention relates generally to apparatus for monitoring the
volume of liquid being drawn from a supply by way of several discharge
conduits, and more particularly to a network flow meter devices
interconnected to provide indications of volume rate of flow and
total flow from each of the plurality of discharge conduits and
the total flow from all such discharge conduits.
II. Discussion of the Prior Art
In fire-fighting systems where water is supplied from a tank on
a fire truck, from a municipal hydrant or from another source such
as a swimming pool or lake, a so-called mid-ship pump is used to
deliver water at high pressure and flow rates to a plurality of
discharge conduits on the fire truck. Such a truck may, for example,
have a water cannon for delivering water at up to 1000 gallons
per minute, several 13/4 to 21/2 inch diameter attack hoses for
directing water onto burning structures at up to 120 gallons per
minute and 1 inch diameter hand lines for extinguishing smaller
fires and extinguishing "hot-spots" once the fire has
been brought under control. Such hand lines may deliver 60 to 90
gallons/minute. In such systems, it is important to know at all
times the total amount of water that has been drawn from a tank
on the fire truck or from the other water supplies as well as the
volume rate of flow and the total flow from each of the separate
hoses and lines. This is especially true when a liquid chemical
foamant concentrate is being added to the water stream. It is important
from the standpoint of optimizing the retardant properties of the
water foamant mixture that the precise amounts of foamant concentrate
be added to the water stream to maintain a predetermined concentration
of the water/foamant mixture.
U.S. Pat. Nos. 5313548; 5232052; 5494112 and RE 35362 owned
by applicants, assignee describe a computer-based system for delivering
metered quantities of foam concentrate to a water stream so as to
maintain the desired concentration. The system includes a positive
displacement pump and a drive motor therefore whose speed can be
varied over a wide range to deliver a foam concentrate from a supply
tank thereof to a discharge conduit. Associated with the main discharge
conduit is a flow meter transducer that feeds information into a
microprocessor as to the existing flow rate of liquid through the
main discharge conduit and this information is processed to cause
the motor to drive the foam concentrate pump at a rate to maintain
a preprogrammed foam/water concentration in the stream being delivered
out the discharge conduit. Also associated with the microprocessor
is a visual display panel which is used to provide a visual indication
to the operator of the volume rate of flow and the total flow during
a given time period.
When it is recognized that a fire truck may have a plurality of
discharge conduits, it is desirable that each individual discharge
conduit have its own flow meter transducer and circuitry for displaying
the volume rate of flow and total flow out each of the plural discharge
conduits. Moreover, it is advantageous that provision be made for
computing and displaying the total flow out of all of the plural
discharge conduits. This allows a fire fighter on board a fire truck
to more readily monitor the volume of water being directed on to
a fire and the rate at which an existing supply is being exhausted.
Knowing the volume of water being directed onto the fire in a multi-story
building allows a determination of when the weight of the water
may be approaching a level where the collapse of a floor may be
expected. Firefighters may then be radioed to retreat from the building
in advance of any structural failure brought on by the weight of
the water delivered. Knowing when the existing supply of water is
exhausted will permit the fire-fighters to leave an area before
the supply runs dry. Furthermore, knowing the size and strength
of a fire-fighter and the flow from the hose he or she is handling,
the flow can be adjusted to accommodate that person's capability
to hold the hose.
SUMMARY OF THE INVENTION
The present invention provides a system for measuring and displaying
the volume of a liquid being drawn from a supply by way of a plurality
of discharge conduits. Each of the discharge conduits has associated
with it a flow meter circuit that includes a flow transducer for
producing pulses at a frequency proportional to the rate of flow
of liquid through its associated discharge conduit. Each of the
flow meter circuits is connected in a series configuration and each
of the flow meter circuits includes microprocessor means that counts
the pulses from the flow transducers and converts the count to volume
rate of flow data and total flow data. The microprocessor means
in each of the flow meter circuits further includes a means for
receiving volume rate of flow data from an adjacent upstream flow
meter circuit in the series configuration and for producing a combined
volume rate of flow value to an adjacent downstream flow meter circuit
in the series configuration. An alpha/numeric display means is coupled
to the microprocessor means in each of the flow meter circuits for
providing a visual manifestation of the volume rate of flow and
total flow data through its associated discharge conduit.
It has been found convenient to include two microprocessors in
each of the series connected flow meter circuits. The first microprocessor
has an input for receiving pulses from its associated flow transducer
and an output for delivering the volume rate of flow data proportional
to the pulse count. The second microprocessor includes a first input
coupled to the output of the first microprocessor and a second input
for receiving the volume rate of flow data from the adjacent upstream
flow meter circuit and an output for delivering the combined volume
rate of flow value to its adjacent downstream flow meter circuit.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic diagram of a fluid handling system with which
the present invention finds application;
FIG. 2 is a schematic electrical diagram of a flow meter system
showing a plurality of flow meter circuits connected in series with
one another and to a controller; and
FIG. 3 is an electrical schematic diagram of the circuitry employed
in each of the flow meter circuits of FIG. 2.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The present invention will be described in a fire-fighting application,
but those skilled in the art will appreciate that the invention
may be otherwise applied to any liquid distribution system wherein
a liquid is being pumped from a supply, such as a water tank 10
and delivered through a plurality of discharge conduits, here shown
as six hoses 12 14 16 18 20 22. In a fire-fighting application,
the water tank 10 may be carried by a fire truck having a mid-ship
pump 24 delivering water under high pressure and flow rate to the
hoses via a manifold 26. Valves, not shown, may be provided to allow
the control of water from the discharge conduits. A typical mid-ship
pump is able to deliver 2000 gallons-per-minute at pressures of
from 100 to 200 psi. The discharge conduits or hoses may be of differing
diameter with smaller diameter hoses being used as "hand lines"
for extinguishing small brush fires or putting out "hot spots"
and smoldering embers at the site of a building fire once the main
blaze has been extinguished. Another, larger diameter hose may lead
to a turret-mounted water cannon designed to deliver a stream of
water over a considerable distance and at a high volume rate of
flow. Still other of the hoses may be conventional 13/4 inch diameter
fire-fighting hoses of the type commonly used on fire trucks.
In carrying out the invention, the water supply need not be a tank,
as at 10 but may just as well comprise a supply of water, such
as a residential swimming pool, or any other supply of water, such
as a lake or pond.
The system represented in FIG. 1 is also shown as including a foam
injection system, such as of the type described in the afore-listed
patents and sold by applicants' assignee, Hypro Corporation, under
the trademark FOAMPRO.RTM.. That system includes a tank 28 for containing
a supply of a foam concentrate that is injected by way of a positive
displacement pump 30 into the output stream from the water supply
pump 24. The foam injection pump 30 is driven by a DC motor 32
the speed of which is modulated by a microprocessor-based controller
34. This allows precise control over the concentration of foamant
relative to the volume of water being delivered. Those desiring
a detailed description of the construction and operation of the
foam injection system are referred to the aforereferenced patents,
the contents of which are hereby incorporated by reference.
With continued reference to FIG. 1 there is shown associated with
each of the discharge conduits 12-22 a flow meter transducer as
at 36. Without limitation, they may comprise paddle-wheels positioned
in the streams exiting the manifold 26 and mounted on each is a
magnet or metallic insert that rotates with the paddle-wheel and
cooperates with a stationary inductive coil or oscillator coil (not
shown) closely positioned relative to the path of travel of the
magnet or metallic insert so as to produce electrical pulses at
a rate proportional to the rate at which the paddle wheel is driven
by the water streams flowing through the discharge conduits.
Referring to FIG. 2 each of the flow meter transducers 36 feeds
the pulses to an associated flow meter circuit as at 38 40 and
42. The flow meter circuits each include an alpha/numeric display
panel 44 and manually operable push-button switches 46 and 48 allowing
an operator to selectively display the volume rate of flow through
a particular discharge conduit, as well as the total flow through
that conduit over a predetermined time interval. The push-button
for selecting rate of flow is labeled "R" and that used
for displaying total flow by the letter "T".
In accordance with the present invention, the individual flow meter
circuits 38 40 and 42 (there being one for each of the discharge
conduits) are connected in a series string with one another and
to the controller 34 which has its own alpha/numeric display panel
50.
As will be described in greater detail hereinbelow, each of the
flow meter circuits is able to receive flow information from an
adjacent upstream flow meter circuit, combine that information with
flow information derived from its own flow meter transducer and
pass the combined flow information on to an adjacent downstream
flow meter circuit. However, the flow meter circuits 38 40 and
42 are only able to provide a visual display of rate of flow and
total flow derived from its own flow meter transducer 36. The controller
34 however, displays the rate of flow and total flow for all of
the discharge conduits as combined or total quantities, i.e., the
sum of the individual readings from all of the flow meter circuits
used in the system.
The individual flow meter circuits 38 40 42 may be separately
located on the fire truck, but preferably will be clustered at a
main control panel along with the controller 34 including a display
50 so that the fire captain can read at a glance the volume rate
of flow and the total flow exiting each of the discharge conduits,
as well as the rate of flow and total flow for all of the discharge
conduits combined.
FIG. 3 is an electrical schematic diagram of the circuitry employed
in implementing each of the individual flow meter circuits 38 40
and 42. Not shown in FIG. 3 is the power supply for converting the
output of the fire truck's generator to a filtered and regulated
DC output of +5 volts that is used to power the circuitry illustrated.
Such power supplies are entirely conventional and need not be described
herein because persons of ordinary skill in electronic design are
able to devise a DC-to-DC switching regulator capable of converting
either a 12 volt DC supply or a 24 volt DC supply down to a 5 volt
level.
The output from the magnetic coil of the transducer 36 is applied
through a coupling resistor 52 to a pulse limiter circuit indicated
generally by numeral 54. It includes a LC filter, including a center-tapped
inductor 56 and a shunt capacitor 58 along with a clamping diode
60. The shaped and limited pulses from the transducer 36 are then
applied to the inverting input of comparitor 62. Without limitation,
the device 62 may comprise an LM 339 device available through National
Semiconductor Corporation. The output from the op amp 62 is fed
back through a resistor 64 to the non-inverting input thereof and
a voltage divider, comprising series connected resistors 66 and
68 applies a predetermined bias to the non-inverting input. The
op amp 62 thus functions such that when the input signal to the
inverting input exceeds a predetermined level, it is considered
as a valid pulse and is applied, via conductor 70 to an input of
a first microprocessor 72. The flow meter transducer 36 produces
a predetermined number of pulses per gallon of liquid flowing through
the particular discharge conduit and the microprocessor is programmed
to count such pulses and convert the pulse count to a gallons-per-minute
reading for presentation on a digital display panel 44. The manner
in which a microprocessor provides digital data, clock information
and selection control signals to a serial display driver is well-known
to persons skilled in the design of microprocessor-based control
systems and is explained in the data sheets for these off-the-shelf
components.
The flow information computed by the microprocessor 72 is also
delivered by way of a serial bus 74 to an input of a second microprocessor
76 along with pulse count information from an adjacent upstream
flow meter. The second microprocessor 76 is programmed to sum the
flow information from the upstream flow meter circuits with the
flow information derived from its own flow meter transducer to produce
an output equal to the resulting total. This combined flow information
is then passed on to an adjacent downstream flow meter circuit.
More particularly, the previous or combined flow from an adjacent
upstream flow meter circuit is applied via a coupling resistor 78
and a filtering and shaping circuit 80 to the inverting input of
a comparitor 82. Without limitation, it may comprise a Type LM339
comparitor chip. The comparitor 82 has a feedback network including
resistor 84 and the voltage divider comprising series connected
resistors 86 and 88. The output from the comparitor 82 is connected
to an input pin of the second microprocessor 76 via connector 90.
The combined flow information from the second microprocessor 76
is applied, via a conductor 92 to an non-inverting input of an
op amp 94 that is configured to function as a cable driver whereby
the combined flow pulse count information may be delivered to the
input terminal 77 of the adjacent downstream flow meter circuit,
via cable 96. In that each of the flow meter circuits is not required
to display its combined flow information, there are no connections
between the second microprocessor 76 and the alpha/numeric display
device 44.
Referring again to FIG. 2 it can now be seen that the input to
the controller module 34 comprises a combined outputs from each
of the plurality of flow meter circuits 38 40 42 etc., and based
upon the total pulse count information which it receives, the microprocessor
contained therein may compute the combined flow rate from all of
the discharge conduits as well as the total flow from the plurality
of conduits during a predetermined time interval.
This invention has been described herein in considerable detail
in order to comply with the patent statutes and to provide those
skilled in the art with the information needed to apply the novel
principles and to construct and use such specialized components
as are required. However, it is to be understood that the invention
can be carried out by specifically different equipment and devices,
and that various modifications, both as to the equipment and operating
procedures, can be accomplished without departing from the scope
of the invention itself. |