Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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TITLE OF THE INVENTION
MACHINE FOR DISPENSING A PREDETERMINED QUANTITY OF
COFFEE
FIELD OF THE INVENTION
The present invention relates to coffee machines. More
specifically, the present invention is concerned with an industrial coffee
machine for dispensing a predetermined quantity of coffee upon request.
BACKGROUND OF THE INVENTION
Coffee dispensing machines are well known in the art.
They usually include a manually operable valve provided with a handle
actuated by a user to fill a cup to an appropriate level. This level is mainly
determined by the hand-eye coordination of the user.
While the operation of this type of coffee dispensing
machine is satisfactory when relatively low volumes of coffee has to be
transferred from a main reservoir to cups, it is not so when the number of
cups to be filled in a small period of time is high, for example, in hospital
kitchens where hundreds of meals are prepared three times a day.
Indeed, for the workers of these volume feeding kitchen
systems, it is generally difficult to manually transfer a predetermined
quantity of coffee cup after cup when the number of cups to be filled is
great and the time allotted to the cup filling operation is short.
Furthermore, the risk of injury to the workers is increased since the
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worker's hands are necessarily in the vicinity of the manual valve during
the transfer operation and may thus be scalded.
Three solutions have been proposed to overcome this
drawback of conventional coffee dispensing machines.
The first solution involves the use of a timer-operated
valve that, when an actuator is depressed, is opened for a predetermined
duration. The drawback with this solution is that the quantity of coffee
transferred by the valve from a main reservoir to a cup is a function of the
quantity of coffee remaining in the main reservoir since the flow rate of
the coffee through the valve is a affected by gravity.
The second solution also involves a timer-operated
valve. However, instead of transferring a quantity of already prepared
coffee from a main reservoir to a cup, a coffee-making syrup is mixed with
hot water upon demand and transferred to the cup. This eliminates the
above-mentioned drawback of the first solution since the hot water is
contained under pressure, thus allowing the quantity of water transferred
to be predetermined. It is however to be noted that the mix of coffee-
making syrup and hot water produces a liquid that does not taste exactly
like coffee that may cause gastric problems.
The third solution involves the use of a type of coffee
machine making the coffee on a cup-by-cup basis upon activation of an
actuator. A major drawback of this solution is the relatively long time
required to brew a cup of coffee each time the machine is activated,
making this type of machines inadequate for volume feeding kitchen
system uses. Furthermore, the quantity of coffee beans required to make
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one cup of coffee with this type of machine is greater than with coffee
machines making a reservoir of coffee at a time.
OBJECTS OF THE INVENTION
An object of the present invention is therefore to provide
an improved machine for dispensing a predetermined quantity of coffee
free of the above-mentioned drawbacks of the prior art.
SUMMARY OF THE INVENTION
More specifically, in accordance with the present
invention, there is provided a machine for dispensing a predetermined
quantity of liquid comprising:
a spout;
a reservoir provided with a fluid outlet;
at least one peristaltic pump having a fluid inlet
connected to the fluid outlet of the reservoir; the at least one peristaltic
pump having a fluid outlet connected to the spout;
a timer connected to the at least one pump; and
a start switch connected to the timer;
wherein, upon activation of the start switch, the timer energizes the at
least one peristaltic pump for a predetermined period of time, thereby
dispensing a predetermined quantity of liquid from the reservoir.
According to another aspect of the present invention,
there is provided a module for dispensing a predetermined quantity of
liquid from the reservoir of a conventional hot liquid machine provided
with a fluid outlet; the module comprising:
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a spout
at least one peristaltic pump having a fluid inlet
connected to the fluid outlet of the conventional hot liquid machine; the
at least one peristaltic pump having a fluid outlet connected to the spout;
a timer connected to the at least one pump; and
a start switch connected to the timer;
wherein, upon activation of the start switch, the timer energizes the at
least one peristaltic pump for a predetermined period of time, thereby
dispensing a predetermined quantity of hot liquid from the reservoir of the
conventional hot liquid machine.
Other objects, advantages and features of the present
invention will become more apparent upon reading of the following non
restrictive description of preferred embodiments thereof, given by way of
example only with reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
In the appended drawings:
Figure 1 is a front elevational view of a coffee machine
according to an embodiment of the present invention; and
Figure 2 is a schematic view of the coffee machine of
Figure 1.
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DESCRIPTION OF THE PREFERRED EMBODIMENT
Turning now to Figure 1 of the appended drawings, a
coffee machine 10 according to an embodiment of the present invention
5 will be described.
The coffee machine 10 includes a body 12, a base 13,
a filter holder 14, a main coffee reservoir 16, a conventional manually
operable valve 18, provided with a first spout 19, and a coffee level
indicator 20. The coffee machine 10 also includes a start switch 22 and
a second spout 24.
The machine 10 may therefore either be used
conventionally by manually operating the valve 18, for example to fill
various size cups (not shown) via the first spout 19, or by actuating the
switch 22 to fill a conventionally sized cup 26 via the second spout 24.
As can be better seen from Figure 2 of the appended
drawings, the coffee machine 10 also includes a cup counter 28, an
electronic timer 30, a primary peristaltic pump 32 a secondary peristaltic
pump 34 and a motor 35 mechanically connected to the pumps 32 and
34.
On the one hand, the switch 22, the counter 28 and the
timer 30 are interconnected to the motor 35 via electrical wires 36, 38 and
40. On the other hand, the motor 35 is connected to the pumps 32 and
34 via mechanical links 41, 42 such as, for example, straps. Or course,
these links 41 and 42 are schematically illustrated in Figure 2. It has
been found that the motor manufactured by Barnant Co. under part
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number D-2504-B is adequate to drive both pumps 32 and 34. This
motor is an AC motor provided with an integrated cooling fan. Of course,
other motors could be used. Preferably, these motors should be
designed to be energized and deenergized every 4 to 5 seconds and
provide enough power to drive both pumps 32 and 34.
The counter 28 indicates the number of times the start
switch 22 has been actuated, hence the number of cups taken from the
reservoir 16. It has been found that counters made by the Eaton
corporation under part number W153094 and name Durant are suitable
for this application.
The timer 30, on the other hand, controls the operation
of the pumps 32 and 34. Generally stated, the timer energizes both
pumps 32 and 34 for a predetermined and adjustable period of time upon
each actuation of the start switch 22.
The main reservoir 16 is connected to the second spout
24 via the pumps 32 and 34. More specifically, a fluid outlet 44, provided
at the bottom of the reservoir 16, is fitted with a first Y-junction 46. A
first
branch 48 of the Y-junction 46 is connected to a fluid inlet 50 of the first
pump 32 via a conduit 52. Similarly, a second branch 54 of the Y-junction
46 is connected to a fluid inlet 56 of the second pump 34 via a conduit 58.
Respective outputs 60, 62 of the pumps 32 and 34 are connected to
branches 64, 66 of a second Y-junction 68 via conduits 70, 72. The
second Y-junction 68 is fitted to the spout 24.
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The second spout 24 includes an air chamber to
decrease the splashing caused by the action of the peristaltic pumps 32
and 34.
Figure 2 also schematically illustrates a pair of heating
elements 74 and 76 electrically connected to a thermostat 78 that controls
their energization. The thermostat 78 includes a temperature sensor 80
provided in the reservoir 16. The thermostat 78 is so programmed that
one of the heating elements 74 and 76 is constantly energized while the
other heating element is only energized when the temperature of in the
reservoir 16 falls under a first predetermined level. Of course, the other
heating element is deenergized when the temperature reaches a second
predetermined level. More specifically, it has been found that if the
reservoir 16 has a capacity of 7.27 gallons (about 33 litres), two 180 watt
heating elements are sufficient to keep the temperature inside the
reservoir 16 at 180 10 F (about 82 6 C).
As will be easily understood by one skilled in the art, the
compartment (not shown) where the electrical elements of the coffee
machine 10 are installed is advantageously provided with louvers allowing
heat to be exhausted. Advantageously, the coffee machine 10 is also
provided with an exhaust fan (not shown) to increase the cooling of this
compartment.
It is to be noted that since the peristaltic pumps 32 and
34, the timer 30, the Y-junctions 46, 68 and the conduits 52, 58, 70 and
72 are exposed to relatively high temperatures, these elements of the
coffee machine 10 must be carefully selected to withstand this
environment. For example, the Y-junctions are advantageously be made
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of stainless steel while the conduits are manufactured by Norton
Company under the name Norprene . The peristaltic pump described in
United States Patent No 4,432,707 to Anderson et al. has been found
suitable for the present application. However, the peristaltic pump
described in United States Patent No 3,358,609 manufactured by Barnant
Company under model number 7035-20 has been found superior since
it includes three rollers in contact with the inner tube of the pump, thereby
preventing leakage of the liquid from the reservoir 16. The principles of
operation of peristaltic pumps are believed well known in the art and will
not be discussed herein for concision purposes.
Of course, the timer 30 may be specifically designed for
this application. However, it has been found that the timer manufactured
by Potter & Brumfield under part number 3702 is adequate since it may
operate under the high temperature of the coffee machine 10.
In operation, when the start switch 22 is actuated by a
user, the counter 28 is incremented and the timer 30 is activated. As
mentioned hereinabove, the timer 30, when activated, energizes the
peristaltic pumps 32 and 34 for a predetermined period of time to cause
a known quantity of coffee to be transferred from the main reservoir 16 to
the cup 26.
Of course, the duration of the predetermined period of
activation of the pumps 32 and 34 by the timer 30 may be adjusted by the
user via controls (not shown) of the timer 30. It is therefor possible to
precisely adjust the quantity of coffee transferred from the main reservoir
to the cups.
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As will be easily understood by one skilled in the art,
since the pumps 32 and 34 are peristaltic pumps, the decreasing level of
coffee in the main reservoir 16 does not adversely affect the quantity of
coffee transferred to the cup.
It is to be noted that even though the coffee machine 10
includes the conventional manually operable valve 18, this valve is not
essential to the invention and could therefore be omitted without
departing from the spirit of the present invention. Similarly, as mentioned
hereinabove, the counter 28 is provided to indicate to the owner of the
coffee machine 10 how many cups of coffee were taken from the main
reservoir 16. Hence, this counter 28 could be removed from the coffee
machine 10 without modifying the coffee transferring operations.
As will be easily understood by one skilled in the art, the
secondary peristaltic pump 34 could be removed without modifying the
operation of the machine 10. Of course, if only one peristaltic pump is
used, the cup filling time is increased. The duration of activation of the
remaining peristaltic pump by the timer 30 should therefore be adjusted
accordingly. This feature is advantageous since the machine 10 could
operate, at lower speed, should one of the peristaltic pump 32 and 34 fail.
For some specific applications, a secondary start switch
(not shown) could be provided and connected to a secondary timer (not
shown) to allow two sizes of cups to be filled via the same pumps and
spout.
It is also to be noted that the timer 30 could be replaced
by a flowmeter (not shown) monitoring the quantity of coffee delivered by
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the spout 24 and stopping the pumps 32 and 34 when the predetermined
quantity is reached.
Of course, the coffee could be replaced by another liquid
5 in the reservoir 16.
As will be apparent to one skilled in the art, the basic
principles of the present invention could be applied to a conventional
reservoir-type coffee machine (not shown) having a conventional
10 manually actuated valve. To achieve this, the start switch 22, the spout
24, the counter 28, the timer 30 and the peristaltic pumps 32 and 34
could be packaged in a separate module provided with a fluid inlet (not
shown) connected to the respective fluid inlets 50 and 56 of the peristaltic
pumps 32 and 34. This fluid inlet would be connected to the spout of the
conventional reservoir-type coffee machine and the manual valve of this
machine would be open. The operation of such a module would be
identical to the operation of the coffee machine 10 described
hereinabove.
Although the present invention has been described
hereinabove by way of preferred embodiments thereof, it can be modified,
without departing from the spirit and nature of the subject invention as
defined in the appended claims.
