U.S. patent application number 09/930324 was filed with the patent office on 2002-09-19 for beverage dispenser having selectable temperature.
Invention is credited to Greenwald, Shlomo, Greenwald, Zipora.
Application Number | 20020130137 09/930324 |
Document ID | / |
Family ID | 25084616 |
Filed Date | 2002-09-19 |
United States Patent
Application |
20020130137 |
Kind Code |
A1 |
Greenwald, Shlomo ; et
al. |
September 19, 2002 |
Beverage dispenser having selectable temperature
Abstract
The present invention dispenses hot coffee or other beverage by
the cup at a selected temperature, which can be varied from
cup-to-cup. The beverage is brewed in a conventional way, and in
one embodiment is stored in a conventional holding tank at elevated
temperature. The holding tank communicates with two smaller
reservoirs. A quantity of beverage is stored in a first reservoir
at an elevated temperature, at or above the maximum desired
dispensing temperature. A second quantity of beverage is cooled and
stored in a second reservoir at a lower temperature, at or below
the minimum desired dispensing temperature. When a cup of beverage
is to be dispensed, the temperature is selected, and a quantity of
beverage is dispensed from each of the reservoirs, proportioned so
that the resulting dispensed beverage is at the selected
temperature. In another embodiment, the first reservoir is omitted,
and beverage from the holding tank provides the elevated
temperature beverage for mixing. In several other embodiments, no
cooling mechanism is needed. Instead, the holding tank is at a
cooler temperature than the lowest vend temperature, and the
beverage must be heated to the hot reservoir temperature and, in
one embodiment, the cold reservoir temperature. In another
embodiment, the holding tank functions as a cold reservoir. In
still another embodiment requiring no heaters, the holding tank is
eliminated, and the beverage is held in insulated chambers at the
higher and lower temperatures.
Inventors: |
Greenwald, Shlomo; (Ithaca,
NY) ; Greenwald, Zipora; (Ithaca, NY) |
Correspondence
Address: |
BROWN & MICHAELS, PC
400 M & T BANK BUILDING
118 NORTH TIOGA ST
ITHACA
NY
14850
US
|
Family ID: |
25084616 |
Appl. No.: |
09/930324 |
Filed: |
August 15, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
09930324 |
Aug 15, 2001 |
|
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|
09769151 |
Jan 24, 2001 |
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Current U.S.
Class: |
222/54 ;
222/144.5; 222/145.5; 222/146.1; 99/279; 99/290 |
Current CPC
Class: |
A47J 31/467 20130101;
A47J 31/50 20130101 |
Class at
Publication: |
222/54 ;
222/146.1; 99/279; 99/290; 222/144.5; 222/145.5 |
International
Class: |
B67D 005/62; B67D
005/08 |
Claims
What is claimed is:
1. A beverage machine for dispensing hot beverages at a selected
temperature in a range between a higher temperature and a lower
temperature, comprising: a) a brew inlet for accepting the beverage
from a source of prepared beverage; b) a holding tank for holding
the beverage at a selected temperature at least as high as the
higher temperature, having an inlet connected to the brew inlet, an
outlet, and a heater for maintaining beverage at the selected
temperature; c) a cold reservoir for holding the beverage at a
selected temperature no higher than the lower temperature, having
an inlet for accepting beverage, an outlet, and a heater for
maintaining beverage at the selected temperature; d) a cooler for
lowering the temperature of a beverage, having an input connected
to the outlet of the holding tank and an output connected to the
inlet of the cold reservoir, such that hot beverage from the
holding tank is cooled as it passes through the cooler to the cold
reservoir; e) a mixing valve having a first input connected to the
outlet of the cold reservoir, a second input connected to the
outlet of the holding tank, and an output producing a mixture of
fluid from the first input and second input, the proportions of
fluid in the mixture from the first input and the second input
being controlled in response to the position of the mixing valve
control; and f) a vending valve having an input connected to the
output of the mixing valve and an output for dispensing the
beverage; such that when the vending valve is opened, beverage is
dispensed having a temperature determined by the position of the
mixing valve control, mixing beverage from the holding tank and
beverage from the cold reservoir.
2. The beverage machine of claim 1, further comprising a
temperature display for showing the temperature of the beverage to
be dispensed, comprising: a) a first temperature sensor for
measuring the temperature of the cold reservoir; b) a second
temperature sensor for measuring the temperature of the holding
tank; c) a valve position sensor coupled to the mixing valve,
having an output which is proportional to the position of the
mixing valve control; d) a display for displaying a temperature; e)
a display control circuit, having a first input connected to the
first sensor, a second input connected to the second sensor, a
third input connected to the valve position sensor, and an output
connected to the display, the display control circuit reading the
temperatures of the holding tank and cold reservoir through the
first and second sensors, and the proportion of beverage dispensed
from the reservoirs at the position of the mixing valve, and
displaying on the display the temperature of the beverage which
would be dispensed.
3. The beverage machine of claim 1, further comprising a dispensed
beverage temperature control for selecting a dispensing
temperature, comprising: a) a first temperature sensor for
measuring the temperature of the cold reservoir; b) a second
temperature sensor for measuring the temperature of the holding
tank; c) a valve position sensor coupled to the mixing valve,
having an output which is proportional to the position of the
mixing valve control; d) a motor coupled to the mixing valve; and
e) a temperature control circuit, having a first input connected to
the first sensor, a second input connected to the second sensor, a
third input connected to the valve position sensor, and an output
connected to the motor, the temperature control circuit reading the
temperatures of the holding tank and cold reservoir through the
first and second sensors, and the proportion of beverage dispensed
from the reservoirs at the position of the mixing valve, and
driving the motor to turn the mixing valve to dispense beverage at
the selected dispensing temperature.
4. The beverage machine of claim 3, further comprising a keypad
connected to the temperature control circuit, such that the
dispensing temperature is entered into the control circuit through
the keypad.
5. The beverage machine of claim 3, further comprising a display
connected to the control circuit, the control circuit displaying
the selected dispensing temperature on the display.
6. The beverage machine of claim 1, in which the cooler comprises:
a) an outer tube having a first end connected to the outlet of the
holding tank and a second end connected to the inlet of the cold
reservoir; b) a heat exchanger surrounding at least part of the
outer tube; c) an inner tube having closed ends, fitted coaxially
inside the outer tube, leaving an annular gap between the inner
tube and the outer tube; d) a wire wound helically around the inner
tube, substantially filling the annular gap between the inner tube
and the outer tube, such that beverage flowing in the first end of
the outer tube is guided helically around the inner tube through
the annular gap to the second end of the outer tube.
7. The beverage machine of claim 6, in which the heat exchanger
comprises tubes carrying cooled fluid.
8. The beverage machine of claim 7, in which the fluid is
water.
9. The beverage machine of claim 6, in which the heat exchange
comprises fins for air cooling on the outside tube, and a fan for
moving air over the fins.
10. A beverage machine for dispensing hot beverages at a selected
temperature in a range between a higher temperature and a lower
temperature, comprising: a) a brew inlet for accepting the beverage
from a source of prepared beverage; b) a holding tank for storing a
quantity of the beverage at a selected temperature in a range
between the higher temperature and the lower temperature, having an
inlet connected to the brew inlet and an outlet; c) a hot reservoir
for holding the beverage at a selected temperature at least as high
as the higher temperature, having an inlet, an outlet, and a heater
for maintaining beverage at the selected temperature; d) a cold
reservoir for holding the beverage at a selected temperature no
higher than the lower temperature, having an inlet for accepting
beverage, an outlet, and a heater for maintaining beverage at the
selected temperature; e) a cooler for lowering the temperature of a
beverage, having an input connected to the outlet of the holding
tank and an output connected to the inlet of the cold reservoir,
such that hot beverage from the holding tank is cooled as it passes
through the cooler to the cold reservoir; f) a fluid heater for
raising the temperature of a beverage, having an input connected to
the outlet of the holding tank and an output connected to the inlet
of the hot reservoir, such that hot beverage from the holding tank
is heated as it passes through the heater to the cold reservoir; g)
a mixing valve having a first input connected to the outlet of the
cold reservoir, a second input connected to the outlet of the hot
reservoir, and an output producing a mixture of fluid from the
first input and second input, the proportions of fluid in the
mixture from the first input and the second input being controlled
in response to the position of the mixing valve control; and h) a
vending valve having an input connected to the output of the mixing
valve and an output for dispensing the beverage; such that when the
vending valve is opened, beverage is dispensed having a temperature
determined by the position of the mixing valve control, mixing
beverage from the hot reservoir and beverage from the cold
reservoir.
11. The beverage machine of claim 10, further comprising a
temperature display for showing the temperature of the beverage to
be dispensed, comprising: a) a first temperature sensor for
measuring the temperature of the cold reservoir; b) a second
temperature sensor for measuring the temperature of the hot
reservoir; c) a valve position sensor coupled to the mixing valve,
having an output which is proportional to the position of the
mixing valve control; d) a display for displaying a temperature; e)
a display control circuit, having a first input connected to the
first sensor, a second input connected to the second sensor, a
third input connected to the valve position sensor, and an output
connected to the display, the display control circuit reading the
temperatures of the hot reservoir and cold reservoir through the
first and second sensors, and the proportion of beverage dispensed
from the reservoirs at the position of the mixing valve, and
displaying on the display the temperature of the beverage which
would be dispensed.
12. The beverage machine of claim 10, further comprising a
dispensed beverage temperature control for selecting a dispensing
temperature, comprising: a) a first temperature sensor for
measuring the temperature of the cold reservoir; b) a second
temperature sensor for measuring the temperature of the hot
reservoir; c) a valve position sensor coupled to the mixing valve,
having an output which is proportional to the position of the
mixing valve control; d) a motor coupled to the mixing valve; and
e) a temperature control circuit, having a first input connected to
the first sensor, a second input connected to the second sensor, a
third input connected to the valve position sensor, and an output
connected to the motor, the temperature control circuit reading the
temperatures of the hot reservoir and cold reservoir through the
first and second sensors, and the proportion of beverage dispensed
from the reservoirs at the position of the mixing valve, and
driving the motor to turn the mixing valve to dispense beverage at
the selected dispensing temperature.
13. The beverage machine of claim 12, further comprising a keypad
connected to the temperature control circuit, such that the
dispensing temperature is entered into the control circuit through
the keypad.
14. The beverage machine of claim 12, further comprising a display
connected to the control circuit, the control circuit displaying
the selected dispensing temperature on the display.
15. The beverage machine of claim 10, in which the cooler
comprises: a) an outer tube having a first end connected to the
outlet of the holding tank and a second end connected to the inlet
of the cold reservoir; b) a heat exchanger surrounding at least
part of the outer tube; c) an inner tube having closed ends, fitted
coaxially inside the outer tube, leaving an annular gap between the
inner tube and the outer tube; d) a wire wound helically around the
inner tube, substantially filling the annular gap between the inner
tube and the outer tube, such that beverage flowing in the first
end of the outer tube is guided helically around the inner tube
through the annular gap to the second end of the outer tube.
16. The beverage machine of claim 15, in which the heat exchanger
comprises tubes carrying cooled fluid.
17. The beverage machine of claim 16, in which the fluid is
water.
18. The beverage machine of claim 15, in which the heat exchange
comprises fins for air cooling on the outside tube, and a fan for
moving air over the fins.
19. The beverage machine of claim 10, in which the fluid heater
comprises: a) an outer tube having a first end connected to the
outlet of the holding tank and a second end connected to the inlet
of the hot reservoir; b) an external heater surrounding at least
part of the outer tube; c) an inner tube having closed ends, fitted
coaxially inside the outer tube, leaving an annular gap between the
inner tube and the outer tube; d) a wire wound helically around the
inner tube, substantially filling the annular gap between the inner
tube and the outer tube, such that beverage flowing in the first
end of the outer tube is guided helically around the inner tube
through the annular gap to the second end of the outer tube.
20. The beverage machine of claim 19, in which the external heater
comprises at least one electric heater which operates
continuously.
21. The beverage machine of claim 19, in which the external heater
comprises at least one electric heater which operates
intermittently.
22. A method of dispensing a beverage at a selected temperature
between a higher temperature and a lower temperature, comprising
the steps of: a) preparing the beverage; b) holding a first
quantity of the beverage in a hot reservoir at a temperature at
least as high as the higher temperature; c) holding a second
quantity of the beverage in a cold reservoir at a temperature no
higher than the lower temperature; d) setting a mixing valve
connected to the hot reservoir and the cold reservoir to mix a
proportion of beverage from the hot reservoir and a proportion of
beverage from the cold reservoir, the proportion being chosen such
that a beverage mixed in the mixing valve will be at the selected
temperature; e) dispensing the beverage at the selected temperature
from the mixing valve.
23. The method of claim 22, in which the step of preparing the
beverage includes the step of holding the beverage in a holding
tank for dispensing.
24. The method of claim 23, in which the step of preparing the
beverage is done in a conventional coffee machine.
25. A beverage machine for dispensing hot beverages at a selected
temperature in a range between a higher temperature and a lower
temperature, comprising: a) a holding tank for holding the
beverage, having an outlet; b) a hot reservoir for holding the
beverage at a selected temperature no lower than the higher
temperature, having an inlet for accepting beverage coupled to the
outlet of the holding tank, an outlet, and a heater for maintaining
beverage at the selected temperature; c) a cold reservoir for
holding the beverage at a selected temperature no higher than the
lower temperature, having an inlet for accepting beverage coupled
to the outlet of the holding tank, an outlet, and a heater for
maintaining beverage at the selected temperature; d) a mixing valve
having a first input connected to the outlet of the cold reservoir,
a second input connected to the outlet of the hot reservoir, and an
output producing a mixture of fluid from the first input and second
input, the proportions of fluid in the mixture from the first input
and the second input being controlled in response to the position
of the mixing valve control; and f) a vending valve having an input
connected to the output of the mixing valve and an output for
dispensing the beverage; such that when the vending valve is
opened, beverage is dispensed having a temperature determined by
the position of the mixing valve control, mixing beverage from the
hot reservoir and beverage from the cold reservoir.
26. The beverage machine of claim 25 wherein the holding tank is
portable.
27. The beverage machine of claim 25, further comprising a
preheater having an inlet coupled to the outlet of the holding tank
and an outlet coupled to the inlet of the cold reservoir and a
volume much smaller than the cold reservoir, such that the beverage
from the holding tank is quickly heated in the volume of the
preheater before being introduced into the cold reservoir.
28. The beverage machine of claim 25, further comprising a
preheater having an inlet coupled to the outlet of the holding tank
and an outlet coupled to the inlet of the hot reservoir and a
volume much smaller than the hot reservoir, such that the beverage
from the holding tank is quickly heated in the volume of the
preheater before being introduced into the hot reservoir.
29. The beverage machine of claim 25, further comprising a
dispensed beverage temperature control for controlling a dispensing
temperature at which the beverage is dispensed, comprising: a) a
temperature selector for inputting a dispensing temperature; b) a
first temperature sensor for measuring the temperature of the cold
reservoir; c) a second temperature sensor for measuring the
temperature of the hot reservoir; d) a motor coupled to the mixing
valve; and e) a temperature control circuit, having a first input
connected to the first sensor, a second input connected to the
second sensor, a third input connected to the temperature selector,
and an output connected to the motor, the temperature control
circuit reading the temperatures of the cold reservoir and the hot
reservoir through the first and second sensors, and the dispensing
temperature from the temperature selector, and driving the motor to
turn the mixing valve to dispense beverage at the selected
dispensing temperature.
30. The beverage machine of claim 29, in which the temperature
selector comprises a keypad connected to the temperature control
circuit, such that the dispensing temperature is entered into the
control circuit through the keypad.
31. The beverage machine of claim 30, in which the temperature
selector further comprises a display connected to the control
circuit, the control circuit displaying the selected dispensing
temperature on the display.
32. A beverage machine for dispensing hot beverages at a selected
temperature in a range between a higher temperature and a lower
temperature, comprising: a) a holding tank for holding the
beverage, having an outlet; b) a hot reservoir for holding the
beverage at a selected temperature no lower than the higher
temperature, having an inlet for accepting beverage coupled to the
outlet of the holding tank, an outlet, and a heater for maintaining
beverage at the selected temperature; c) a mixing valve having a
first input connected to the outlet of the hot reservoir, a second
input connected to the outlet of the holding tank, and an output
producing a mixture of fluid from the first input and second input,
the proportions of fluid in the mixture from the first input and
the second input being controlled in response to the position of
the mixing valve control; and f) a vending valve having an input
connected to the output of the mixing valve and an output for
dispensing the beverage; such that when the vending valve is
opened, beverage is dispensed having a temperature determined by
the position of the mixing valve control, mixing beverage from the
hot reservoir and beverage from the holding tank.
33. The beverage machine of claim 32, in which the holding tank is
portable.
34. The beverage machine of claim 32, further comprising a
preheater having an inlet coupled to the outlet of the holding tank
and an outlet coupled to the inlet of the hot reservoir and a
volume much smaller than the hot reservoir, such that the beverage
from the holding tank is quickly heated in the volume of the
preheater before being introduced into the hot reservoir.
35. The beverage machine of claim 32, further comprising a
dispensed beverage temperature control for controlling a dispensing
temperature at which the beverage is dispensed, comprising: a) a
temperature selector for inputting a dispensing temperature; b) a
first temperature sensor for measuring the temperature of the
holding tank; c) a second temperature sensor for measuring the
temperature of the hot reservoir; d) a motor coupled to the mixing
valve; and e) a temperature control circuit, having a first input
connected to the first sensor, a second input connected to the
second sensor, a third input connected to the temperature selector,
and an output connected to the motor, the temperature control
circuit reading the temperatures of the hot reservoir and holding
tank through the second sensor and the first sensor, and the
dispensing temperature from the temperature selector, and driving
the motor to turn the mixing valve to dispense beverage at the
selected dispensing temperature.
36. The beverage machine of claim 35, in which the temperature
selector comprises a keypad connected to the temperature control
circuit, such that the dispensing temperature is entered into the
control circuit through the keypad.
37. The beverage machine of claim 35, in which the temperature
selector further comprises a display connected to the control
circuit, the control circuit displaying the selected dispensing
temperature on the display.
38. A beverage machine for dispensing hot beverages at a selected
temperature in a range between a higher temperature and a lower
temperature, comprising: a) a hot chamber for holding the beverage
at a selected temperature no lower than the higher temperature,
having an outlet; b) a cold chamber for holding the beverage at a
selected temperature no higher than the lower temperature, having
an outlet; c) a mixing valve having a first input connected to the
outlet of the cold chamber, a second input connected to the outlet
of the hot chamber, and an output producing a mixture of fluid from
the first input and second input, the proportions of fluid in the
mixture from the first input and the second input being controlled
in response to the position of the mixing valve control; and d) a
vending valve having an input connected to the output of the mixing
valve and an output for dispensing the beverage; such that when the
vending valve is opened, beverage is dispensed having a temperature
determined by the position of the mixing valve control, mixing
beverage from the hot chamber and beverage from the cold
chamber.
39. The beverage machine of claim 38, in which the hot chamber and
the cold chamber are part of a portable unit.
40. The beverage machine of claim 38, further comprising a
dispensed beverage temperature control for controlling a dispensing
temperature at which the beverage is dispensed, comprising: a) a
temperature selector for inputting a dispensing temperature; b) a
first temperature sensor for measuring the temperature of the cold
chamber; c) a second temperature sensor for measuring the
temperature of the hot chamber; d) a motor coupled to the mixing
valve; and e) a temperature control circuit, having a first input
connected to the first sensor, a second input connected to the
second sensor, a third input connected to the temperature selector,
and an output connected to the motor, the temperature control
circuit reading the temperatures of the cold chamber and hot
chamber through the first sensor and the second sensor, and the
dispensing temperature from the temperature selector, and driving
the motor to turn the mixing valve to dispense beverage at the
selected dispensing temperature.
41. The beverage machine of claim 40, in which the temperature
selector comprises a keypad connected to the temperature control
circuit, such that the dispensing temperature is entered into the
control circuit through the keypad.
42. The beverage machine of claim 40, in which the temperature
selector further comprises a display connected to the control
circuit, the control circuit displaying the selected dispensing
temperature on the display.
43. A method of dispensing a beverage at a selected temperature
between a higher temperature and a lower temperature, comprising
the steps of: a) preparing the beverage at a brewing center; b)
cooling the beverage at a brewing center; c) transferring the
beverage to the service location in a portable holding tank; d) at
the service location, coupling the portable holding tank to a
beverage dispensing machine having a hot reservoir and a cold
reservoir; e) holding a first quantity of the beverage in a hot
reservoir at a temperature at least as high as the higher
temperature; f) holding a second quantity of the beverage in a cold
reservoir at a temperature no higher than the lower temperature; g)
setting a mixing valve connected to the hot reservoir and the cold
reservoir to mix a proportion of beverage from the hot reservoir
and a proportion of beverage from the cold reservoir, the
proportion being chosen such that a beverage mixed in the mixing
valve will be at the selected temperature; h) dispensing the
beverage at the selected temperature from the mixing valve.
44. A method of dispensing a beverage at a selected temperature
between a higher temperature and a lower temperature, comprising
the steps of: a) preparing the beverage at a brewing center and
transferring a portion of the beverage to a hot chamber; b) cooling
a portion of the beverage at the brewing center and transferring
the portion of the beverage which was cooled to a cold chamber; d)
at a service location, coupling the hot chamber and the cold
chamber to a beverage dispensing machine having a mixing valve
coupled to the hot chamber and the cold chamber; e) setting the
mixing valve to mix a proportion of beverage from the hot chamber
and a proportion of beverage from the cold chamber, the proportion
being chosen such that a beverage mixed in the mixing valve will be
at the selected temperature; f) dispensing the beverage at the
selected temperature from the mixing valve.
45. The method of claim 44 in which the hot chamber and the cold
chamber are part of a portable holding tank.
Description
REFERENCE TO RELATED APPLICATION
[0001] This is a continuation-in-part of parent patent application
Ser. No. 09/769,151, filed Jan. 24, 2001. The aforementioned
application is hereby incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The invention pertains to the field of fluid dispensers.
More particularly, the invention pertains to beverage dispensing
machines having temperature regulation of the dispensed
product.
[0004] 2. Description of Related Art
[0005] In most aspects of our life, each individual person has his
or her own preferences. For example, people prefer different kind
of food, different kind of spices in food and so on. This is also
true when it comes to coffee--each person likes to drink his coffee
at a different temperature. Especially in fast food restaurants and
coffee shops, the temperature of the coffee that is sold is most
often very hot, much too hot for most people to drink. So each
person has to wait until his coffee will cool to his or her desired
temperature, which might take 10 to 20 minutes. This become very
irritating, especially when you want to drink your coffee right
away and the only way to do it is by small sips, and even then you
will burn your tongue. Since we have the free choice to buy our
food according to our preference, why not the temperature of our
coffee?
[0006] Industrial coffee machines typically have two main parts: a
brewer and a container where the coffee is stored. Normally, for
best results coffee is brewed at a temperature of near or just
below boiling--about 200.degree.-210.degree. F. Then, the coffee is
stored at a reduced temperature, so as not to cause the flavor to
deteriorate too badly. The coffee temperature in the storing
container is maintained at about 180.degree. F. or more by a
regulated or continuous heater or an outside heat plate.
[0007] Thus, the temperature of the coffee that is served is about
180.degree. F., which is too hot to drink--for most people a
drinkable coffee temperature is between 130.degree. to 150.degree.
F. In fast food restaurants the coffee is served in paper cups, the
paper material of the cup is a good heat insulator and has very
small heat capacity. Therefore its takes quite a long time until
the coffee cools down to the desired drinkable temperature for each
individual. Since the customer does not know what is the coffee
temperature he will probe the coffee temperature by taking small
sips.
[0008] By doing so he might burn his tongue and the inside of his
mouth. Also many customers would like to drink their coffee right
away with their food and not have to wait until the coffee will
cool to the desired temperature. One study showed that while coffee
shops tend to serve coffee between 168.degree. F. and 187.degree.
F., but a survey of 225 consumers showed the largest group
preferred their coffee at 140.degree. F. or 160.degree. F.
(O'Mahoney, et. al, "At What Temperature Should You Serve Coffee?",
1999 Annual Meeting of the Institute of Food Technologists, Report
50B-1).
[0009] There have been a number of U.S. patents covering devices
for dispensing beverages, especially coffee or tea, at different
temperatures.
[0010] Cornelius, U.S. Pat. No. 3,634,107, "Apparatus for
Dispensing Coffee Beverage" (1972) is a vending machine which
stores carbonate coffee concentrate at ambient temperature (or
refrigerated non-carbonated concentrate). On a vending request, it
mixes a selected volume of the coffee concentrate with cold and hot
water to dispense coffee at a selected temperature and
concentration. Unlike the present invention, Cornelius' vending
machine does not dispense fresh coffee, and requires maintenance of
volumes of water and coffee concentrate at various
temperatures.
[0011] In Haynes, U.S. Pat. No. 4,550,651, "Batch-brewing Coffee
System" (1985), coffee is brewed in batches, and stored at reduced
temperature in a holding tank. When a cup is desired, the brewed
coffee is heated by passage through a heat exchanger in a heating
tank. The Haynes device cannot set a specific temperature for each
cup of coffee.
[0012] In Verheijen, U.S. Pat. No. 4,791,860, "Equipment for
Supplying Hot Water" (1988), the user sets temperature of water
desired for beverage. The temperature is controlled by passing
water through flow-through heater for specific time, then turning
off heater or bypassing heater, so cold water is dispensed for
specific time, mixing to produce water of selected temperature.
Verheijn does not provide brewed coffee, but rather water of a
selected temperature, and requires complicated flow-through
heaters, mixing valves, and timing circuitry.
[0013] Kerner et al, U.S. Pat. No. 4,792,059, "Sealed Hot, Cold and
Room Temperature Pure Water Dispenser" (1988) is a water dispenser
which contains hot and cold reservoirs fed from holding tank. Three
valves control water dispensed, so the user has a choice of hot,
cold or water at something between room temperature and tap
temperature, but cannot select a specific temperature of the water.
Kerner does not brew coffee or other beverages, but is simply an
office water cooler/heater which can dispense water at three
temperatures.
[0014] Anson, et al, and Anson patents, assigned to the well-known
industrial and office coffee-maker manufacturer Bunn-o-Matic, (U.S.
Pat. Nos. 4,920,871, 5,584,229, and 5,858,437) all provide coffee
brewers which can brew a beverage at the normal 200.degree. F.
temperature, but dispense it into a carafe at a reduced
temperature, where it is presumably kept at the lower temperature
for pouring into customers' cups. Anson's machines use a two-part
brewing funnel which has a bypass channel for colder water. The hot
brewing water goes through the coffee grounds or tea leaves in the
center of the basket or funnel, and mix with the colder water in
the bypass channel. Anson cannot vary the temperature of each cup
of coffee (the customer's coffee is poured at whatever temperature
the carafe is kept at), and the cooler the desired temperature, the
more dilute the beverage as more cold water is mixed with the brew
output.
[0015] Usherovich, U.S. Pat. No. 5,724,883, "Hot/Cold Beverage
Brewing Device" (1998) is a home-type coffee or tea maker which, in
addition to the conventional coffee brewing mechanism, has a second
carafe which can store the brewed beverage at a lower temperature
by passing the hot beverage through an exchanger with a cooling
medium, and then diluting the hot concentrate with cold water.
There is no option for dispensing a cup of brewed beverage at a
specific temperature, and, as a dilution system, the lower the
temperature to be dispensed, the weaker the beverage.
SUMMARY OF THE INVENTION
[0016] The present invention dispenses hot coffee or other beverage
by the cup at a selected temperature, which can be varied from
cup-to-cup. The beverage is brewed in a conventional way, and in
one embodiment is stored in a conventional holding tank at elevated
temperature. The holding tank communicates with two smaller
reservoirs. A quantity of beverage is stored in a first reservoir
at an elevated temperature, at or above the maximum desired
dispensing temperature. A second quantity of beverage is cooled and
stored in a second reservoir at a lower temperature, at or below
the minimum desired dispensing temperature. When a cup of beverage
is to be dispensed, the temperature is selected, and a quantity of
beverage is dispensed from each of the reservoirs, proportioned so
that the resulting dispensed beverage is at the selected
temperature. In another embodiment, the first reservoir is omitted,
and beverage from the holding tank provides the elevated
temperature beverage for mixing.
[0017] In the present invention the original but colder coffee is
mixed with the original but hotter coffee to adjust the coffee
temperature to the desired one. Because of this we preserve the
coffee quality by not changing the strength or the taste of the
coffee, only its temperature. This is superior to those systems
which use cold water, diluting the coffee strength and changing its
taste.
[0018] In the present invention the cold and the hot reservoirs are
refilled automatically from the main holding tank. Therefore the
system requires only one single mixing valve to control the coffee
temperature, making the present system simpler and more reliable.
The simple system of the invention also allows much more accurate
control of temperature than the reheat or dilution systems.
[0019] The system of the invention can serve single users where
each patron can choose and receive coffee at different temperature.
In addition he will receive the coffee at the chosen temperature
independent of the quantity he is pouring out.
[0020] In one embodiment, the system of the invention can be
directly added to existing commercial coffee makers without making
any changes to the coffee makers, improving the quality and the
taste of the coffee because:
[0021] the coffee can be brewed at the optimal temperature to get
the best coffee--about 200.degree. F. Today, most coffee makers
have a brewing temperature around 180.degree. F. because of safety
concerns.
[0022] in the two-reservoir plus holding tank embodiment of the
invention, the coffee in the holding tank can be stored at lower
temperature which will extend the time that the coffee can stand
without loosing its quality. This is possible because in our system
the coffee temperature that is poured out is independent on the
coffee temperature in the holding tank.
[0023] Adding the system of the invention to existing coffee makers
will eliminate the need of a heater or external hot plate used to
keep the coffee in the holding tank at high temperature
(180.degree. F.). Instead only the small amount (5 to 10%) in the
hot reservoir of the system has to be that hot. This will lower the
cost of operating the coffee maker.
BRIEF DESCRIPTION OF THE DRAWING
[0024] FIG. 1 shows a schematic representation of a first
embodiment of the invention, having a holding tank and hot and cold
reservoirs.
[0025] FIG. 2 shows a schematic representation of a second
embodiment of the invention, having a holding tank and a cold
reservoir.
[0026] FIG. 3 shows a schematic detail of a hot reservoir for use
with the invention.
[0027] FIG. 4 shows a schematic detail of a cold reservoir for use
with the invention.
[0028] FIG. 5 shows a schematic representation of a manual
temperature selection mechanism for use with the invention.
[0029] FIG. 6 shows a schematic representation of an automatic
temperature selection mechanism for use with the invention.
[0030] FIG. 7 shows a flowchart of a method of operation of the
automatic temperature selection mechanism of FIG. 6.
[0031] FIG. 8 shows a schematic of a circuit for use with the
manual temperature selection mechanism of FIG. 5.
[0032] FIG. 9 shows a schematic of a third embodiment of the
invention having a portable holding tank and both hot and cold
reservoirs.
[0033] FIG. 10 shows a schematic of a fourth embodiment of the
invention having a portable holding tank and a hot reservoir.
[0034] FIG. 11 shows a schematic of a fifth embodiment of the
invention having a portable holding tank with a hot chamber and a
cold chamber.
[0035] FIG. 12 shows a schematic of an apparatus for brewing and
cooling the beverage at a brewing center.
DETAILED DESCRIPTION OF THE INVENTION
[0036] A schematic drawing of the coffee maker of the invention can
be seen in FIG. 1. The coffee is brewed in a conventional manner,
and the brewing mechanism is not shown. The brewed coffee enters a
holding tank (2) through pipe (1) at whatever the brewing
temperature is--typically between 195.degree. F. and 205.degree. F.
The holding tank (2) is a conventional feature of industrial coffee
brewers, and is typically around 10 gallons in size for a typical
fast-food restaurant. The size of the holding tank is not important
to the teachings of the invention.
[0037] The coffee temperature in the holding tank (2) is regulated
at a temperature which is referred to as "T.sub.t", which is lower
than the temperature of the coffee after brewing (usually about
180.degree. F.). The exact value of T.sub.t will be determined by
the requirements of the particular application--a lower temperature
will last longer, but if the temperature is too low it might
require significant reheating for service.
[0038] In addition to the holding tank (2), this embodiment of the
invention has two smaller reservoirs, referred to herein as the
"cold" reservoir (3), kept at a temperature of T.sub.c, and the
"hot" reservoir (4), kept at a temperature of T.sub.h. These
reservoirs are smaller than the holding tank--in an embodiment
where the holding tank is five to ten gallons, the reservoirs would
preferably be about one-half to one gallon each. Smaller dispensing
machines would use smaller reservoirs, but the reservoirs will need
to contain at least a few cups of beverage each, as will be seen in
the discussion below.
[0039] The "hot" temperature, T.sub.h, will need to be greater than
or equal to the highest temperature at which it would be desired to
dispense the beverage--for most coffee dispensers a temperature of
about 180.degree. F. would be preferred, although some restaurants
might want to have this even higher--as much as 195.degree. F.
According to one report (O'Mahoney, et. al, "At What Temperature
Should You Serve Coffee?", 1999 Annual Meeting of the Institute of
Food Technologists, Report 50B-1) coffee shops serve coffee between
168.degree. F. and 187.degree. F., and it is reported that
McDonalds dispenses coffee at closer to 190.degree. F.
[0040] The "cold" temperature, T.sub.c, will need to be less than
or equal to the lowest temperature at which it would be desired to
dispense the beverage--about 120.degree. F. is preferred, although
this temperature could be set higher or lower as desired.
[0041] In a preferred embodiment, the coffee temperature in the
holding tank (2) will be lower than the coffee temperature in the
hot reservoir (4), but higher than the temperature in the cold
reservoir (3) (i.e. T.sub.h>T.sub.t>T.sub.c). As a result,
the coffee from the holding tank (2) will need to pass from the
exit pipe (17) through a heater (16) before it enters the hot
reservoir (4), so its temperature will be close to the desired hot
reservoir temperature T.sub.h. On the other hand, the coffee from
the holding tank (2) to the cold reservoir (3) will be cooled by a
cooler (15) to be reduced to (or below) the cold reservoir
temperature T.sub.c. With the use of the heater (16) and cooler
(15), the reservoir temperatures will not be significantly changed
from the desired T.sub.h and T.sub.c as the supply of coffee in the
reservoirs is drawn off and new coffee is drawn in from the holding
tank (2).
[0042] Vent lines (19) lead from the hot (4) and cold (3)
reservoirs back to the top of the holding tank (2) to avoid
problems due to backpressure as coffee fills the reservoirs from
the holding tank.
[0043] Output pipe (5) from the cold reservoir (3) and output pipe
(6) from the hot reservoir (4) feed a mixing valve (7). In a
simpler embodiment, the desired coffee temperature is selected by
rotating the selector handle (18) on a mixing valve (7), which
mixes the coffee coming from the cold reservoir (3) with the coffee
coming from the hot reservoir (4). The mixed coffee is dispensed
into the cup (10) from the mixing valve output (8) through a
dispensing valve (9). The selected coffee dispensing temperature
can thus vary continuously from T.sub.c, (the temperature of the
cold reservoir), if the mixing valve is set to draw only from pipe
(5), to T.sub.h, (the temperature of the hot reservoir) if the
mixing valve is set to draw only from pipe (6). At any intermediate
setting, the dispensing temperature will depend on the mixture.
[0044] FIG. 2 shows an alternative embodiment of the invention, in
which the hot reservoir is replaced by a direct feed line (26) from
the holding tank (2). This embodiment can be built as a simpler
version of the embodiment of FIG. 1, above, or installed as an
add-on module (21) to an existing industrial coffee or other hot
beverage maker, in which case the holding tank (2) will be the
conventional holding tank in the coffee maker, and pipe (17) would
be connected to the normal output of the coffee maker.
[0045] When built as an add-on module (21), the coffee temperature
in the holding container of such coffee makers is sufficiently high
(T.sub.h.about.180 F.), that a separate hot reservoir is not
needed. If built as a simpler add-on unit than the two-reservoir
system of FIG. 1, the holding tank temperature would be set at a
temperature which is at or above the hottest temperature at which
it is desired to dispense the beverage (T.sub.t=T.sub.h). Instead,
a line (26) from the output (17) of the holding tank (2) is
connected directly to the hot inlet of the mixing valve (7). As in
the first embodiment described above, the cold reservoir (3) is
connected to the holding tank (2) output (17) via a cooling system
(15) that cools down the incoming coffee from T.sub.h to a
temperature near T.sub.c.
[0046] The rest of the system of this embodiment is the same as
described above for the embodiment of FIG. 1.
[0047] FIG. 3 shows a detail of the hot reservoir of the invention,
as is used in the embodiment of FIG. 1. The volume of the hot
reservoir (4) is small relative to the holding tank (2), preferably
about one-half gallon or smaller, and it is preferably built with
good heat insulation in its walls (37). In a preferred embodiment,
the reservoir (4) is built with its walls in two layers, with air
or vacuum between the walls, similar to a vacuum flask
construction. Alternatively, foam or other insulation can be
provided in the walls.
[0048] The temperature of the coffee in the reservoir (4) is
continuously regulated to T.sub.h, preferably within about
.+-.1.degree. F. using an inside heater (36), powered and
controlled by conventional temperature regulating circuitry (35).
The incoming coffee from output (17) of the holding tank will be
heated by a heat exchange to closely match the coffee temperature
T.sub.h in the hot reservoir.
[0049] A preferred embodiment of a heat exchanger useful with the
invention is built from an inner (31) and an outer (38) concentric
tube, where the inner tube (31) is used as a filler and the coffee
flows in between the two tubes. A wire (30) whose diameter is equal
to the spacing between the two tubes (31) and (38) is wound in a
helix type winding around the inner tube (31). This will force the
coffee to flow in a thin layer very close to the outer tube (38),
which is hot, in a helical long path. It will also convert the flow
from laminar to a turbulent, which will increase the efficiency of
the heating. The helical path can be made ten times longer then the
straight path. The heat exchanger is preferably thermally
insulated.
[0050] In order to be able to heat the incoming coffee very fast
the heat exchanger will preferably have two heaters. A first heater
(33) is low power which will operate continuously to keep the heat
exchanger at high temperature approximately equal to T.sub.h. The
second heater (32) will operate in pulse mode, and will provide the
power that is needed to heat the incoming coffee. It may be turned
on by the opening of the output valve and turned off by the closing
of the output valve, or by sensing coffee flow in the exchanger, or
thermally, or in any other way which might be desired. The heaters
are powered and controlled by conventional control circuitry
(34).
[0051] FIG. 4 shows a detail of the cold reservoir (3) of the
invention. As in the hot reservoir described above, the volume of
the cold reservoir (3) is also preferably about one-half gallon or
smaller, and it, too, is built with insulation (45) in the walls.
Again, two layers walls with air or vacuum between the walls, as in
a vacuum flask, will provide good heat insulation, or other
insulating materials such as foam can be used.
[0052] The temperature of the coffee in the cold reservoir is
continuously regulated to T.sub.c, preferably within a range of
.+-.1.degree. F., using an inside heater (43) powered and
controlled by conventional circuitry (44).
[0053] The incoming coffee from the output (17) of the holding tank
is cooled down to a temperature approximately equal to, or slightly
less than T.sub.c by a heat exchanger. FIG. 4 shows this heat
exchanger structures much the same as the heat exchanger for the
hot reservoir shown in FIG. 3: an inner (31) and outer (38)
concentric tube, where the inner tube (31) is used as a filler and
the coffee flows in between the two tubes. A wire (30) whose
diameter is equal to the spacing between the two tubes (31) and
(38) is wound in a helix type winding around the inner tube (31).
This will force the coffee to flow in a thin layer very close to
the outer tube (38), which is cooled by cooler (40), in a helical
long path. It will also convert the flow from laminar to a
turbulent, which will increase the efficiency of the cooling. The
helical path can be made ten times longer then the straight path.
The heat exchanger is preferably thermally insulated.
[0054] The cooler (40) used in this heat exchanger may work in any
one of the ways known to the art, under the control of appropriate
circuitry and supply (42). For example, tap water can be circulated
around the exchanger, in which case (42) would comprise a pump or
valve and circuitry to start and stop the pump or open and close
the valve in a conventional manner in response to operation of the
output valve, or by sensing coffee flow in the exchanger, or
thermally, or in any other way which might be desired.
Alternatively, the heat exchanger can be cooled by a forced air
cooling system, in which a fan is used to increase the airflow
across radiating fins. In such a case, (42) would be a power supply
for the fan, in a conventional manner in response to operation of
the output valve, or by sensing coffee flow in the exchanger, or
thermally, or in any other way which might be desired. Other
cooling methods, such as solid-state Peltier elements, controlled
by appropriate circuitry, are possible within the teachings of the
invention.
[0055] In its simplest form, the beverage dispensing system of the
invention could use a simple mixing valve (7), with a calibrated
scale showing the approximate temperature provided by the position
of the handle (18). The position of the mixing valve determines the
mixing ratio between the cold and the hot coffee. If desired, a
thermometer, preferably digital, could read out the temperature of
the beverage as it's dispensed, allowing for finer adjustment
during dispensing.
[0056] It is preferred, however, to be able to dispense coffee or
other hot beverages with the temperature regulated to a finer
degree than would be possible with such a relatively crude setup.
FIGS. 5 and 6 show details of two temperature control systems which
may be used within the teachings of the invention, which provide
for manual and automatic adjustment of the temperature of the
dispensed beverage, respectively.
[0057] In both figures, mixing valve (7) has a manual operating
handle (18), which can select the proportion of cold and hot
beverage dispensed from inlet pipes (5) and (6), respectively. The
beverage output of the mixing valve (7) is preferably mixed in a
mixing tube (54), which is preferably covered in thermal insulation
(55), so as to maintain the selected temperature of the beverage as
long as possible, and the flow is controlled by the dispensing
valve (9). The output mixing tube is constructed in a similar way
as the heat exchanger that was described in FIGS. 3 and 4. It is
constructed in this way to ensure a) fast mixing between the hot
and cold coffee b) to minimize the amount of the trapped coffee
between the two valves.
[0058] Feedback of the position of the valve (7) is provided by
ganging the valve (7) to a potentiometer (51) through gearing (53)
and (52). For maximum accuracy, the potentiometer is preferably of
the precision multi-turn type, and the gearing is chosen to rotate
the potentiometer a number of times for a full revolution of the
valve (7) handle (18) --a 5:1 or 10:1 ratio would be preferable,
depending on the number of turns available on the potentiometer
(five turn or ten turn). The potentiometer can be viewed as a
voltage divider comprising two resistors R.sub.1 and R.sub.2 in
series, in which the voltage present at the center of the divider
(wiper) will be proportional to the position of the valve. The
temperature of the cold reservoir is sensed by a sensor (12), and
similarly the temperature of the hot beverage source (hot
reservoir, as in FIG. 1, or holding tank as in FIG. 2) is sensed by
sensor (13). A digital readout (11) preferably provides a display
of the temperature
[0059] In the manual system of FIG. 5, the coffee temperature is
selected by rotating the handle (18) on mixing valve (7). In order
to ensure that the accuracy of the selected coffee temperature will
not be effected by the fluctuation of the coffee temperature in the
cold and hot reservoirs (or in the holding tank, in the embodiment
of FIG. 2), the temperatures of the coffee in both reservoirs are
continuously measured by sensors (12) and (13), and the measured
temperatures at the time when the selection is made together with
the mixing valve position is used to calculate the poured coffee
temperature.
[0060] The poured coffee temperature T.sub.p is given by: 1 T p = (
R t - R 1 R t ) T c + ( R t - R 2 R t ) T h
[0061] where R.sub.1 and R.sub.2, as explained above, are the
resistances of the two portions of the potentiometer on either side
of the wiper, and R.sub.t=R.sub.1+R.sub.2. Thus it can be seen that
if R.sub.1=0 when the mixing valve is turned all the way to the
left (counterclockwise), and the hot coffee inlet is closed, then
the output coffee temperature will be equal to the cold reservoir
temperature T.sub.c. On the other hand, if when R.sub.2=0 the
mixing valve is turned all the way to the right and the cold coffee
inlet is closed, the output coffee temperature will be equal to the
hot reservoir coffee temperature.
[0062] It will be understood by one skilled in the art that in a
practical circuit the values of R.sub.1 and R.sub.2 may be measured
directly and the formula above used, or preferably, by using the
potentiometer as a voltage divider--applying a voltage across the
potentiometer and measuring the voltage at the wiper--the position
of the wiper may be determined indirectly, and the temperature
determined according to this formula: 2 T p = ( 1 - V w V s ) T c +
( V w V s ) T h
[0063] where V.sub.w is the voltage at the wiper (junction of
R.sub.1 and R.sub.2), and V.sub.s is the source voltage applied
across the potentiometer.
[0064] The display unit (50) for this embodiment of the invention,
as shown in the schematic representation of FIG. 5, determines
T.sub.c from sensor (12), and T.sub.h from sensor (13). As
indicated in the figures, a source voltage V.sub.s is applied to
the full clockwise (CW) end of potentiometer (51) (the free end of
R.sub.2), a ground reference is applied to the full
counterclockwise (CCW) end of potentiometer (51) (the free end of
R.sub.1), and V.sub.w is read from the wiper (junction of R.sub.1
and R.sub.2). Using the formula above, when the user sets the
handle (18) of the mixing valve (7) to a given position, the
display unit calculates the temperature of the beverage which will
be dispensed with the mixing valve (7) in its current position, and
displays the temperature on the readout (11).
[0065] FIG. 8 shows a detailed schematic of a circuit which could
be used to implement the manual embodiment of FIG. 5. It should be
noted that the conventional power supply wiring and chip
connections is omitted in the schematic for simplicity. It will be
understood by one skilled in the art that the circuit will require
an appropriate power supply, depending on the integrated circuits
chosen, and each IC will need appropriate connections to the power
supply.
[0066] The two temperature inputs, T.sub.c and T.sub.h, are sensed
by sensor ICs U1 and U2, respectively. These integrated circuits
can be LM34 temperature sensors, manufactured by National
Semiconductor. The LM34 accepts a voltage input of between +5 and
+20 VDC, and outputs a voltage of +10.0 mV/.degree. F.
[0067] The output T.sub.c of sensor U1 is fed into the "+" input of
an amplifier U3, preferably a low-noise operational amplifier such
as an NE5534 integrated circuit from Texas Instruments or Signetics
(although any of the many op amps available with suitable
characteristics could be used). The "-" input is connected to
ground with resistor R11, and also to the output of the op amp
through resistor R12. The "+" input is also connected to ground
through resistor R13 (R13=R11.parallel.R12). The output of the op
amp V.sub.c (90) is thus given by the formula, 3 V c = ( R 11 + R
12 R 11 ) T c
[0068] The mixer valve position resistor (81) is a multi-turn
potentiometer, as described in FIG. 5, above, coupled to the mixer
valve. One end of the potentiometer is fed by a regulated voltage
V.sub.s from a voltage reference (82), and the other end grounded.
The voltage regulator is preferably any one of the many voltage
regulator integrated circuits, such as an LM7810, available from
many different manufacturers, or could be built with discrete
components or a variable voltage regulator IC such as the LM317.
The wiper voltage from the potentiometer V.sub.w provides an
indication of the position of the mixing valve.
[0069] V.sub.s, V.sub.w and V.sub.c (90) are fed as the X1, X2 and
Y1 inputs, respectively, into U5, an analog multiplier IC such as a
MPY634 available from Burr-Brown. The Y2 input is grounded. The
output (88) of the multiplier IC is given by the formula, 4 Output
( 88 ) = V c ( V s - V w 10 )
[0070] Similarly, the output T.sub.h of sensor U2 is fed into the
"+" input of an amplifier U4, preferably a low-noise operational
amplifier such as an NE5534 integrated circuit from Texas
Instruments or Signetics (although any of the many op amps
available with suitable characteristics could be used). The "-"
input is connected to ground with resistor R3, and also to the
output of the op amp through resistor R4. The "+" input is also
connected to ground through resistor R14 (R14=R3.parallel.R4). The
output of the op amp V.sub.h (91) is thus given by the formula, 5 V
h = ( R 3 + R 4 R 3 ) T h
[0071] V.sub.w and V.sub.h (91) are fed as the X1 and Y1 inputs,
respectively, into U6 an analog multiplier IC such as a MPY634
available from Burr-Brown. The X2 and Y2 inputs are grounded. The
output (89) of the multiplier IC is given by the formula, 6 Output
( 89 ) = ( V w V h 10 )
[0072] Output (88) of U5 and output (89) of U6 are fed, through
resistors R4, into the "-" input of amplifier U7. As in U3 and U4,
U7 can be any of the commonly available low noise operational
amplifiers, such as the NE5534 integrated circuit from Texas
Instruments or Signetics (although any of the many op amps
available with suitable characteristics could be used). Feedback
resistor R5 connects the "-" input to the output (87) of the op
amp, and the "+" input is grounded by resistor R6
(R6=R4.parallel.R4.parallel.R5). Thus, the output (87) of U7 is
given by the formula, 7 Output ( 87 ) = - R 5 R 4 [ ( 10 - V w 10 )
V c + V w V h 10 ]
[0073] Output (87) is fed, through resistor R7, into the "-" input
of operational amplifier U8, which also can be any of the commonly
available low noise operational amplifiers, such as the NE5534
integrated circuit from Texas Instruments or Signetics (although
any of the many op amps available with suitable characteristics
could be used). Feedback resistor R9 connects the "-" input to the
output (86) of U8. A correction voltage V.sub.cor is picked off a
potentiometer (84), and fed to the "-" input of U8 through resistor
R8. V.sub.cor allows for correction of the output voltage for
coffee in the valve, as discussed below, or for other inaccuracies
in the system. The "+" input of the op amp is grounded through
resistor R10 (R10=R7.parallel.R8.parallel.R9). The output (86) of
U8 is thus given by the formula, 8 Output ( 86 ) = Output ( 87 ) R
9 R 7 - V cor R 9 R 8
[0074] Finally, the voltage at output (86) is read by digital
display (85), which can be any one of many available digital
voltmeters having an appropriate scale, such as 0-199 mV or the
like.
[0075] In the automatic embodiment shown in FIG. 6, the customer or
waitperson will type in the temperature of the coffee he would like
to have on keyboard (65) and the control system (60) will rotate
the mixing valve (7) to the right position using a motor (63) with
a shaft (61) attached to a drive gear (62), which can couples to
the smaller gear (51) on the potentiometer (51) or the larger gear
(53) on the valve (7).
[0076] Once a temperature is entered on the keypad (65), the
control system (60) will calculate the initial position of the
mixing valve using the potentiometer (51) in the same way as was
described in above. In addition, the control system, which will
preferably work in a closed loop feedback mode, will calculate the
temperature of the mixed coffee, using the inputs from sensors (12)
and (13) and the valve position and the formulas above, and will
adjust the position of the mixing valve (7) with the motor (63),
until the mixing valve (7) is positioned such that the calculated
mixed coffee temperature will match the selected temperature. The
display (11) can be set to either display the selected temperature
or the calculated temperature, or perhaps both, either
simultaneously or alternately.
[0077] FIG. 7 shows a flowchart of a possible method of operation
of this automatic temperature selection mechanism. The method of
the flowchart works as follows:
[0078] 70. The method starts--variables are initialized, etc., in a
conventional manner.
[0079] 71. The user inputs the desired temperature (T.sub.d) at the
keyboard (65).
[0080] 72. The system displays the entered temperature on the
display (11) for confirmation. If desired, the system could require
a confirming keystroke at this point.
[0081] 73. The temperature (T.sub.c) of the coffee in the cold
reservoir (3), the temperature (T.sub.h) of the coffee in the hot
reservoir (4) and the mixing valve (7) position are measured.
[0082] 74. The vend temperature (T.sub.p) is calculated from
T.sub.c, T.sub.p and the current valve position, in accordance with
the formula 9 T p = ( 1 - V w V s ) T c + ( V w V s ) T h
[0083] where V.sub.w is the voltage at the wiper (junction of
R.sub.1 and R.sub.2), and V.sub.s is the source voltage applied
across the potentiometer.
[0084] 75. The vend temperature T.sub.p calculated in step 74 is
displayed on the display (11).
[0085] 76. The desired temperature T.sub.d is compared to the vend
temperature (T.sub.p) at the current mixing valve setting.
[0086] 77. If T.sub.d<T.sub.p, the servo motor (63) is
activated, turning the mixing valve (7) counterclockwise.
[0087] 78. If T.sub.d>T.sub.p, the servo motor (63) is
activated, turning the mixing valve (7) clockwise.
[0088] The method then loops back from either step 77 or step 78 to
measure the valve position and temperatures in step 73.
[0089] 79. If T.sub.d=T.sub.p, then the desired temperature has
been reached, and the dispensing valve (9) is opened. This can be
done automatically, or, if desired, manually by the customer or
waitstaff.
[0090] 80. After a time delay to allow the cup to fill, the
dispensing valve is closed, and the method loops back to await a
new temperature entry at step 71.
[0091] In an even more automated application, in larger places
where coffee is served to patrons the control system (60) of
multiple coffee machines of the invention can be connected to the
order entry registers. Customers will order the kind of coffee and
the temperature of the coffee they would like to have. This
information with the order I.D. number of each register will be
stored in system memory in the control unit (60). When a restaurant
employee fills a customer order, he/she will either use the
keyboard to type in the customer order number, or might even recite
the order number via a microphone (not shown). Using that
information the control system (60) of the invention will
automatically adjust the mixing valve (7) as described above, so
the served coffee will have the ordered temperature.
[0092] If desired, the system can include some compensation for the
effects on the vend temperature of the small amount of coffee
trapped in the mixing valve (7), or between the mixing valve (7)
and the dispensing valve (9). With appropriate attention to
minimizing the amount of trapped coffee, these effects can be
minimized, but there will still be some effect, since this coffee
will be at some other temperature than the selected vend
temperature of the coffee coming from the mixing valve once the
flow starts. If there has been a while between vends, the coffee,
this trapped coffee will have had time to cool off. If there is
only a short time between vends, the coffee will be at or near the
last-selected vend temperature, which could be cooler or hotter
than the current vend temperature.
[0093] The effects of trapped coffee can be compensated for by
including an averaging factor for the known volume of the trapping
volume. Alternatively, a temperature sensor at or near the vending
valve (9) can measure the actual temperature of the coffee as it is
dispensed, and compensate by slightly increasing or decreasing the
vend temperature for part of the stream, or, as shown in the
schematic in FIG. 8, a fixed compensation can be built into the
circuitry.
[0094] The described in above are the preferred embodiment for the
case when the coffee holding tank (2) is a part of a coffee maker.
The coffee that is brewed at high temperature is stored in the
holding tank (2) at high temperature and when the coffee runs out
of the holding tank new coffee is brewed and stored in the holding
tank. Using the beverage dispenser, as described in FIG. 1 or 2,
each customer can select the temperature of his coffee as he or she
desires.
[0095] The following embodiments of the invention, which are
described in FIGS. 9 to 11, are the preferred embodiments for the
case when the coffee holding tank (95) is portable and is not
attached to a coffee maker. The portable tank can be filled with
fresh brewed coffee at a location that is far from the place where
the coffee is served using the invention.
[0096] In this case the portable holding tanks can be filled with
freshly brewed coffee at coffee brewing centers where the coffee
can be brewed at the best conditions to achieve the highest coffee
quality, preferred taste and any desired flavor. In order to
preserve the coffee quality and taste the coffee will preferably be
cooled down to low temperature while filling the portable tank by
using heat exchangers. The portable tanks will be stored at low
temperature. The portable tank will be delivered to the service
location (restaurants, hotels, business offices, parties) where the
portable tank (95) will be coupled to a beverage-dispensing-sys-
tem as described in FIGS. 9 to 11. Using the dispensing system each
customer can select the temperature of his/her coffee as he/she
wishes.
[0097] Brewing the coffee at brewing centers and delivering the
coffee in portable tanks to the place of service and dispensing the
coffee using the invention has a number of advantages compare to
the way coffee is served today.
[0098] At brewing centers sophisticated brewing machines can be
used to achieve higher quality and better tasting coffee, which are
too expensive to be used in restaurant or business offices
[0099] Because of the centralization, the high quality coffee can
be delivered to any place at lower price than it will cost to make
at the service location using their own coffee maker.
[0100] These embodiments of the invention will probably cost less
than an average size coffee maker.
[0101] There will also be the option of renting the beverage
dispenser having selectable temperature from the coffee distributor
either for a single use (party) or for a longer term use
(restaurants or business offices). It will eliminate the burden and
save the time of preparing the coffee. It will give the business
owner the freedom to order a different quantity of coffee i.e,
different size tank, according to the need per that day. It will
allow each place to have many different coffee flavors. Using the
invention will allow each patron to choose the temperature of his
coffee as he desires.
[0102] A schematic drawing of this embodiment of the invention to
which a portable coffee tank is coupled can be seen in FIG. 9. The
coffee is brewed at a brewing center, where sophisticated brewing
machines and methods will be used to achieve high quality coffee.
The very hot coffee coming out of the brewer will preferably be
cooled down to room temperature or cooler to preserve the quality
and taste of the coffee for a longer time. The cooling can be done
using a brazed plates heat exchanger, in which the cooling water,
whose temperature at the exit of the heat exchanger will be only
few degrees lower than the hot coffee coming out of the brewer,
will be returned to the coffee brewer as hot water. This will allow
saving of up to 70-80 percent of the power that is needed to heat
up the water in the brewer as will be explained in FIG. 12.
[0103] In the following embodiments of the machine of the
invention, therefore, there is no need for cooling the coffee to
T.sub.c as in the embodiments described above, eliminating the need
for cooling elements in the machine. If the cooler coffee for the
mixing valve is modified in temperature from the tank coffee at
all, it will be heated--a more economical approach, as heating
elements are less expensive than cooling systems.
[0104] The cold coffee will be stored in portable holding tanks
(95) having different sizes. The portable tank (95) has a vent
valve (96) on the top and a special coupling valve (97) to the
dispensing system on the bottom. The freshly brewed cold coffee
will be delivered to the locations of service (restaurants,
business-offices, hotels, parties, and more) where the portable
tank (95) will be coupled to the system of the invention (100).
Using this dispensing system each patron will be able to choose the
temperature of his coffee as he desires.
[0105] The coffee temperature in the portable tank (95), which is
referred to as "T.sub.t" , is at room temperature or cooler. The
exact value of T.sub.t will be determined by the requirements to
preserve the quality and taste of the coffee for a long time.
[0106] In this embodiment of the invention the dispensing system
has two reservoirs referred to herein as the "hot" reservoir (103),
kept at regulated temperature T.sub.h, and the "cold" reservoir
(104), kept at regulated temperature T.sub.c. The volume of these
reservoirs are smaller than the portable tank, preferably one half
gallon to one gallon each.
[0107] The "hot" temperature T.sub.h will need to be greater than
or equal to the highest temperature at which it will be desired to
dispense the beverage. For most coffee dispensers a temperature of
180-190 .degree. F. would be preferred. The "cold" temperature
T.sub.c will be less than or equal to the lowest temperature at
which it would be desired to dispense the beverage--about
120-130.degree. F. is preferred, although this temperature can be
higher or lower as desired.
[0108] In the preferred embodiment, the coffee temperature in the
portable tank (95) will be much lower then the temperature of the
"cold" reservoir (104) (i.e. T.sub.h>T.sub.c>>T.sub.t). As
a result, the coffee from the portable tank (95) will need to pass
from the exit pipe (115) through a "fast heater" (101) before its
enters the hot reservoir (103), so its temperature will be close to
the desired hot reservoir temperature T.sub.h. Also, the coffee
from the portable tank (95) will need to pass from the exit pipe
(115) through an additional "fast heater" (102) before its enters
the cold reservoir (104), so its temperature will be close to the
desired cold reservoir temperature T.sub.c. The preferred internal
volume of the "fast heaters" (101,102) is equal to the size of a
large cup of coffee (12-16 oz.) and the coffee temperature in the
"fast heaters" is regulated to be equal to T.sub.h and T.sub.c,
respectively. In this way, the moment a serving of coffee is
dispensed, the new coffee that is entering the reservoir (103) from
the fast heater (101) and reservoir (104) from the fast heater
(102) will be at the right temperature. Therefore, it will not
cause significant temperature fluctuation in the hot and cold
coffee reservoirs. The new cold coffee that is drawn from the
portable tank into the "fast heater" (101) and (102) will be heated
by the fast heating elements (118,120). Assuming 1500 watt heating
elements (118,120) are used in the "fast heaters", the system will
be able to dispense 150 large cups of coffee per hour--five gallons
of coffee.
[0109] The heating elements (119) and (121) in the hot and cold
reservoir are used mainly for temperature regulation.
[0110] Vent lines (116) from the hot and cold reservoirs (103,104)
and vent lines (114) from the "fast heaters" (101,102) lead back to
the top of the portable tank (95) to avoid flow problems due to
back pressure as coffee fills the "fast heaters" and the
reservoirs.
[0111] Output pipe (123) from the hot reservoir (103) is connected
to one input of the mixer valve (105) and output pipe (124) from
the cold reservoir (104) is connected to the second input of the
mixer valve (105). The mixed coffee is dispensed into a cup from
the mixer valve output (130) through a dispensing valve (106). The
selected coffee dispensing temperature can be thus varied
continuously from T.sub.c (the temperature of the cold reservoir)
if the mixer valve is set to draw only from the cold reservoir, to
T.sub.h (the temperature of the hot reservoir) if the mixer valve
is set to draw only from the hot reservoir. At any intermediate
setting, the dispensing coffee temperature will depend on the
mixture.
[0112] The preferred mixer valve (105) will be constructed by
coupling two linear valves using a 1:1 ratio gear and using
commercial valve driving controller which uses a step-motor and
microprocessor to drive one valve. Since the two valves are coupled
together by a 1:1 gear, when one will be opened the second will be
closed by the same amount.
[0113] The input command to the valve controller is preferably
either a voltage in the range of 1 to 5 volts or a current of 4 to
20 ma. For a 1 volt (4 ma) input command the master valve (the
valve that is driven by the step motor) will be closed and the
slave valve will be open while for a 5 volt (20 ma) input command
the master valve will be open and the slave valve will be close. At
any intermediate input command the relative position of each valve
is linearly proportional to the input command voltage
(current).
[0114] The temperatures of the coffee in the "fast heater"
(101,102) and the reservoirs (103,104) are continuously measured
using temperature sensors (125,126,127,128. The sensors are
connected to the electronics interface board (109) which amplify
and scales the sensors signal. The output of the interface board
(109) is connected to the system main microprocessor (110). The
microprocessor (110) uses the measured temperatures to regulate the
coffee temperatures in the "fast heaters" (101,102), the hot (103)
and the cold (104) reservoirs. The regulating output, TTL level
signals, from the microprocessor are connected to the heating
elements (118,119,120,121) interface board (107,108) which include
fast switching transistors and relays. The relays are used to
switch on/off the AC voltage to the heating elements as needed.
[0115] The temperature of the dispensed coffee is selected by using
two control buttons, the "up" button (112) and the "down" button
(113), and the selected temperature is displayed in the numerical
display (111). By pressing once on the up button (112) the
dispensed coffee temperature will increment by a chosen
amount--preferably one degree--and by pressing once on the down
button (113) the dispensed coffee temperature will decrement by the
same amount. By pressing continuously on the up/down buttons the
dispensed coffee temperature will be increased/decreased
continuously--preferably at a rate of about three degrees per
second--and the temperature display (111) will also change at the
same rate.
[0116] The system microprocessor (110) will adjust the mixer valve
(105) position to correspond to the new selected coffee temperature
at the same rate of three degrees per second.
[0117] The microprocessor (110) uses the measured temperature
T.sub.h (126) of the hot reservoir (103) and the measured
temperature T.sub.c (128) of the cold reservoir (104) and the newly
selected coffee temperature T.sub.p to calculate the new position
of the master valve.
[0118] The microprocessor (110) can use the following
algorithm:
[0119] If we define a parameter X as the position of the "master"
valve (the valve which is driven by the step-motor) and 1-X as the
position of the "slave" valve we can write the selected coffee
temperature as
T.sub.p=XT.sub.c+(1-X)T.sub.h
[0120] From which we can find that the new position X of the master
valve corresponding to T.sub.p is given by 10 X = T h - T p T h - T
c
[0121] where the parameter X can change from 0 (closed valve) to 1
(completely open valve).
[0122] In the above derivations the output (124) of the cold
reservoir (104) is connected to the master valve input while the
output (123) of the hot reservoir (103) is connected to the slave
valve input.
[0123] In practice, the mixer valves are not exactly linear in the
whole range from closed to open position. Therefore, in order to
ensure that the dispensed coffee temperature will be whitin one
degree of the selected one, we will provide fine position
adjustment by feedback from the actual dispensed coffee
temperature. The actual dispensed coffee temperature is measured by
temperature sensor (129) which is mounted at the mixer valve output
pipe (130). The fine adjustment is accomplished by modifying the
mixer valve positions that correspond to the selected temperature:
11 X = T h - T p + T f T h - T c
[0124] Where T.sub.f is the correction from feedback. T.sub.f is
obtained by periodically accumulating the error of the outlet
temperature--preferably about fifteen times per second. Each time
T.sub.f is incremented by the scaled difference between the actual
dispensed coffee temperature T.sub.o and the selected coffee
temperature T.sub.p:
T.sub.f=S*(T.sub.o-T.sub.p)+T.sub.f, with
-T.sub.m<T.sub.f<T.sub.m,
[0125] Where T.sub.m is a limit on the maximum magnitude of the
feedback correction. From this, one can see that if T.sub.o is too
high, the controller (110) will progressively increase X. i.e.
increase the flow rate from the cold reservoir and decrease the
flow rate from the hot reservoir until T.sub.o is correct, and the
opposite if T.sub.o is too low. S is a scale factor that determines
the response time of the feedback. The constants S and T.sub.m
together determine the amount of temperature overshoot that will
occur when dispenser flow is started, and can be adjusted to
compensate for cool-off of the coffee trapped in the outlet pipe
and the mixer valve (105) between uses.
[0126] FIG. 10 shows an alternative embodiment of the invention, in
which the cold reservoir (104) and the "fast heater" (102) are
replaced by a direct feed line (124) from the cold portable tank
(95) to the input of the mixer valve (105). This embodiment can be
built as a simpler version of the embodiment of FIG. 9. As in the
embodiment described in FIG. 9, the hot reservoir (103) is
connected to the portable tank (95) output (115) via a fast heater
(101) that heats up the incoming coffee from T.sub.t to
T.sub.h.
[0127] The rest of the system of this embodiment is the same as
described above for the embodiment of FIG. 9.
[0128] In case where there are no adequate power outlets to operate
the beverage-dispenser, such as at outdoor events or conferences at
hotels where the coffee is rolled in during coffee break the
preferred embodiment of the invention is shown in FIG. 11. In this
embodiment, the coffee is stored at the Brewing Center in a special
insulated portable tank (150) which is divided into two chambers
(151,152). The very hot coffee coming out of the brewer is stored
in the large chamber (151) while the cooled down coffee is stored
in the smaller chamber (152). The coffee that is stored in the
smaller chamber (152) is cooled to room temperature or higher as it
comes out of the brewer using a heat exchanger as is described in
FIG. 12. The special portable tank (150) has two vent valves
(153,154) at the top and two output ports (155,156). At the place
of service the portable tank (150) is coupled to the apparatus of
the invention (140).
[0129] In this simplified dispenser, the coffee from the hot
chamber (151) is connected directly via a pipe (159) to one input
of the mixer valve (105) while the cold coffee from the smaller
chamber (152) is connected directly via a pipe (160) to the second
input of the mixer valve (105). The mixed coffee is dispensed into
a cup from the mixer valve output pipe (130) through a dispensing
valve (106). The main microprocessor (110) is using the
continuously measured temperatures of the coffee in the hot chamber
(151), T.sub.h, by the temperature sensor (157) and the coffee in
the cold chamber (152), T.sub.c, by temperature sensor (158), and
the selected temperature, T.sub.p, to calculate and adjust the
mixer valve position as was described in the embodiment of FIG. 9.
The rest of the dispenser system is the same as was described in
FIG. 9.
[0130] This embodiment of the system (140) will preferably be
operated by batteries similar to the one used in power tools. Each
dispenser will include two batteries, one active and the other as
backup.
[0131] An alternative method to operate the dispenser (140) will be
to use a low power battery to operate the controller electronics
and select the desired coffee temperature using a manual system as
was described in FIG. 5. The dispensed coffee temperature
corresponding to the new position of the mixer valve (105) will be
calculated by the microprocessor (110) and displayed in the
numerical display (111).
[0132] In the above embodiment of the invention, even so the coffee
is stored in the portable tank at high temperature, the high
quality and taste of the coffee will be preserved since it will be
stored in the portable tank only for relatively short time. Because
in outdoor events and conferences coffee break the coffee is
consumed in short time.
[0133] At the brewing center the freshly brewed hot coffee will be
cooled down before it will be stored in the portable tank (95). In
FIG. 12 a cooling method is shown which will allow saving 70-80
percent of the power that is needed to heat up the water for the
coffee in the brewer.
[0134] In this method, the cold water for the coffee which is
stored in holding tank (200) is also used to cool the hot coffee
coming out of the brewer (201) using a brazed plates Heat-Exchanger
(202). The hot brewed coffee coming out from the brewer (201) is
connected by pipe (204) to the Heat-Exchanger (202) hot side input
port #1. The cooled down coffee exits through the hot side output
port #2 which is connected via pipe (205) to the portable tank
(95). The cold water from tank (200) is connected by pipe (207) to
the Heat-Exchanger cold side input port #3. The heated water exits
through the cold side output port #4 which is connected via pipe
(206) to the water input of the coffee brewer (201). Since the
temperature of the water at the exit from the Heat-Exchanger will
be only few degrees cooler than the temperature of the hot coffee
coming out of the brewer (210), upon entering the coffee brewer it
will need to be heated only by an additional few degrees.
[0135] Accordingly, it is to be understood that the embodiments of
the invention herein described are merely illustrative of the
application of the principles of the invention. Reference herein to
details of the illustrated embodiments is not intended to limit the
scope of the claims, which themselves recite those features
regarded as essential to the invention.
* * * * *