Note: Descriptions are shown in the official language in which they were submitted.
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This invention relates to metering devices for liq-
uids and more particularly to such devices which respond to
the flow of the liquid as opposed to the volume after
dispensing.
One such dev ce is incorporated in petrol pump
dispensers and comprises a rotatable turbine in the petrol
dispensing line. Either directly, or magnetically, coupled
counters respond to the rotation to calculate the volume and
value of petrol passing through the line for dispensing.
These turbine-type metering devices, however, are unsuitable
for use with the dispensing of carbonated and/or pressurised
beverages, such as beer. It frequently occurs that these
dispensing lines contain only, or a large quantity of, froth
which, while operating the turbine, is undesirable to be
included in the metered volume.
On licensed premises employing staff for the dis-
pensing of beer on tap it has been found necessary to exercise
supervision to ensure that the quantity dispensed during a
period of trading corres~onds to the money deposited in cash
registers. Flowmeter systems have been associated with the
beer lines to the taps but hitherto the dispensed quantities
recorded have been far from accurate due to the occurrence of
froth and gas in the lines frequently during trading, for
example when kegs are replaced or gas pressures are incorrectly
adjusted.
It is the main object of the invention to provide a
liquid-flow metering device which is efficient and accurate in
operation even in the dispensing of carbonated and/or press-
urised beverages.
According to the invention there is provided a liquid-
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flow metering device comprising a flowmeter for indicating
externally of a dispensing line a liquid flow therein, an
electrical impulse generator, and an electrical impulse
counter driven by impulses from said generator, a fluid volume
calculator, and driver means responding to said flowmeter to
control the operation of said calculator, the latter having
a maximum input signal rate to permit response only to signals
indicative of fluid flow below a predetermined rate.
The invention will be better~understood with
reference to the accompanying drawings, in which:-
FIG. 1 shows a schematic diagram of the metering
device of the invention;
FIGS. 2A and 2B are a plan and a sectional view of
a flowmeter utilized with the device;
FIG. 3 is a perspective view of the calculator
housing of the device; and
~IG. 4 is an end elevation of said housing with the
battery compartment door open.
A preferred embodiment of the invention will now be
described wherein the fluid-flow metering device is utilized
for the dispensing of beer with automatic indication of the
quantity of beer dispensed for each pulling operation.
Reference is now made to FIG. 1 showing schematically
the electrical construction of the device. Any form of flow-
meter 1 may be provided and preferably incorporates electrical
contacts A actuated by a rotatable ceramic magnet 2, within
the beer dispensing line 3 responding to the flow of beer
there-through. Under normal circumstances where the dis-
pensing line 3 is connected to a beer keg (not shown) properly
supplied with pressurising gas, no foaming of the beer occurs
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in the flowmeter 1. It is a recognised phenomenon that most
flowmeters will respond not only to the flow of liquid ~eer but
also to the passage of beer froth in the line. This will
~requently occur upon the depletion of beer in a keg and with
changeover, either manually or automatically, to a fresh keg.
The present invention is possible due to the realisation that
both gas and froth in the dispensing line 3 traverses at a
much faster rate than the fluid, in the order o~ 10 times the
normal rate of flow of beer. Thus, it can be seen that com-
pletely inaccurate automatic calculations of dispensed volumes
of beer occur with conventional flowmeters whenever froth or
gas is present in the line.
Electrical contacts A, therefore, function as a
magnetically sensitive reed switch which is operated by the
permanent magnet 2 connected with the measuring portion lA of
the flowmeter 1. Upon completion of one measuring cycle by
the flowmeter 1 a closed condition occurs of the reed contacts.
Connections from the reed switch A are made between a calcu-
lator 4 and a reset circuit consisting of three stages, viz. an
oscillator (or clock) 5, a counter 6, and driver unit 7.
The clock oscillator 5 is a conventional ~hree gate,
unit, comprising gates Gl, G2 and G3, whose frequency is con-
trolled b~ resistors Rl and R2, and capacitor Cl. Its
operating frequency is about Hz6. The counter 6 receives
clock pulses from the oscillator 5 which would normally drive
the counter 6 throu~h its counting range which in this case
is 0 - 9. It would repeat the cycle continuously as long as
clock pulses from oscillator 5 are present were it not for its
decoded output "7" being tied to the "clock enable" input.
When output "7" is reached a logic high is sent to "clock
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enable", thereby inhibiting further coun~ing. At this stage
output "7" remains high. All other outputs from counter 6
are low.
On application of a high to the input "reset" of the
counter 6, by manual, or automatic, activation of the RESET
switch decoded output "7" goes low removing inhibiting and
allowing the counter 6 to count through the output steps "1",
"3", "5", "7" and then to stop stepping. The outputs from "1"
to "7" are buffered by a quad bilateral switch 7. The drivers
of switch 7 are connected directly to the electrical connect-
ions corresponding to the function keys "Clear", "Read Memory",
"Add" and "Equals" of the calculator 4. Thus the outputs of
the counter 6 are connected as follows:
Decoded output "1" = Clear key
Decoded output "3" = Read Memory key
Decoded output "5" = Add key
Decoded output "7" = Equals key (and this halts stepping by
the counter 6).
Thus, whenever contacts A close the high from output
"7" is repeatedly applied to the calculator. The effect is
the same as pulsing the "equals" key, thereby adding to the
total displayed on the calculator the value entered into the
memory with each pulse. The value programmed will be initially
measured precisely to repres~nt the quantity of beer dispensed
for each operating cycle of the flowmeter. Each cycle will be
the interva:L covering each successive operation of the reed
switch A. Xt is a feature o~ the calculator that its speed of
response to the pulsing frequency of the contacts A of the
flowmeter 1 has an upper threshold which excLudes response to
a frequency between that derived from normal beer flow in the
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line 3 and that derived ~rom the passage of gas or froth in
the line 3 (being in the order of 1:10).
A special feature of the flowmeter 1, therefore, is
that, if gas either continuosly or intermittently flows through
the meter 1, although the meter 1 pulses the "e~uals" key of
the calculator 4 when this gas is present, it is not recorded
by the calculator due to the calculator's maximum input rate
being limited by its inherent design. In one ~orm the
calculator 4 incorporates the semi-conductor chip NEC 888.
The flowmeter 1 shown in FIGS. 2A and 2B is ideally
suited for incorporation within the device. It is composed of
a housing 8 having inlet and outlet adaptors 9 and 10 for
connection within a beer line 3. A removable core 11 in the
housing 8 is sealed by opposite O-rings 12 and 13 against the
inner wall of the housing 8 and has a through passage occupied
by a rotor 15 which oscillates with ithe flow of beer in the
passage to rotate an axial spindle 16 and a ceramic magnet 2
carried on one end thereof. The contacts A are embedded in the
housing 8 adjacent the magnet 2 to close when attracted or
repelled by an appropriate pole of the magnet 2 as it passes
in juxtaposition to the contacts A. This type of flowmeter 1
has a stable metering quality in service. Calibration is
obtained for programming of the memory bank of the calculator
by flow comparison with a previously calibrated flowmeter 1.
In the application of the liquid-flow metering device
of this invention in licensed clubs or other premises where
beer is dispensed from a plurality of taps and by various
employees, it will be customary for each employee to be
assigned an individual tap and cash register. A record of
cash transactions over a trading period will be maintained by
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conventional means associated with the register, while a re-
cord of the quanti~y of beer dispensed will be displayed upon
the calculator 4 (FIG~. 3 and 4) corresponding to the
assigned beer tap. The calculator 4 preferably is located
together with other calculators 4, related to the remaining
taps, at a recording location remote from the beer taps.
FIGS. 3 and 4 show one such calculator 4 enclosed
within a securable case 18 provided with a cylinder lock 19
and key 20 on a hinged front cover 24. .The calculator ~ is
mounted above a printed circuit board 21 containing the
electronic components shown in FIG. 1. A battery compartment
22 is located beneath the board 21 and an end wall 23 of the
case 18 is hinged to provide access to the compartment 22.
The hinged front cover 24 has a viewing window 25 over the
display 26 of the calculator 4 and also is provided with a
second cylinder lock 27 and key 28 which through cam 29
effects actuation of the switch 30 mounted upon an end of the
board 21. The switch 30 is the switch RESET of FIG. 1 and is
operated by the supervisor's key 28 to cancel the total dis~
played on the calculator 4 before trading commences.
A reading of the calculator's displayed total beer
volume will be made at the end of trading before the cust-
omary flu~hing of the beer pipes. At the supervisor's con-
venience this record is later checked with the cash total
recorded by the register. Due to the different rate of charge
for beer depending upon the volume served, appropriate keys
and record ~lill be provided by the register for indicating
volume per ~;ervice which traditionally is one of merely three
or four difi'erent volumes.
W~lereas.a preferred embodiment has been described.by
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the foregoing it ahould be appreciated that other forms are
feasible within the scope of the invention.
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