U.S. patent application number 12/519229 was filed with the patent office on 2010-02-04 for icemaker refrigerator provided therewith and ice making method.
This patent application is currently assigned to BSH BOSCH UND SIEMENS HAUSGERATE GMBH. Invention is credited to Joachim Damrath, Stefan Holzer, Andreas Renner, Markus Spielmannleitner, Gerhard Wetzl.
Application Number | 20100024442 12/519229 |
Document ID | / |
Family ID | 39431663 |
Filed Date | 2010-02-04 |
United States Patent
Application |
20100024442 |
Kind Code |
A1 |
Damrath; Joachim ; et
al. |
February 4, 2010 |
ICEMAKER REFRIGERATOR PROVIDED THEREWITH AND ICE MAKING METHOD
Abstract
An icemaker for a refrigerator is provided that includes a mold
container which may be filled with water, an air space adjacent to
a water level in the mold container, and an air humidifying device
for increasing the level of humidity in the air above the water
level. Water is administered to the mold container and is cooled
and ice crystals form when a given crystallization temperature of
the water of below zero degrees C is reached.
Inventors: |
Damrath; Joachim;
(Bachhagel, DE) ; Holzer; Stefan; (Aalen, DE)
; Renner; Andreas; (Giengen, DE) ;
Spielmannleitner; Markus; (Ellwangen, DE) ; Wetzl;
Gerhard; (Sontheim, DE) |
Correspondence
Address: |
BSH HOME APPLIANCES CORPORATION;INTELLECTUAL PROPERTY DEPARTMENT
100 BOSCH BOULEVARD
NEW BERN
NC
28562
US
|
Assignee: |
BSH BOSCH UND SIEMENS HAUSGERATE
GMBH
Munich
DE
|
Family ID: |
39431663 |
Appl. No.: |
12/519229 |
Filed: |
November 30, 2007 |
PCT Filed: |
November 30, 2007 |
PCT NO: |
PCT/EP07/63098 |
371 Date: |
June 15, 2009 |
Current U.S.
Class: |
62/66 ;
62/347 |
Current CPC
Class: |
F25C 2700/04 20130101;
F25C 2600/04 20130101; F25C 1/24 20130101; F25C 2400/14 20130101;
F25D 23/12 20130101; F25C 2400/10 20130101; F25D 17/042 20130101;
F25C 2600/02 20130101; F25C 1/00 20130101 |
Class at
Publication: |
62/66 ;
62/347 |
International
Class: |
F25C 1/00 20060101
F25C001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 22, 2006 |
DE |
10 2006 061 100.4 |
Claims
1-25. (canceled)
26. An ice-maker comprising: a mold container configured to be
filled with water and an air space adjacent to a surface of water
in the mold container; and an air humidifier, the air humidifier
being operable to humidify air in the air space above the surface
of water in the mold container to thereby bring the air to a
predetermined moisture level.
27. The ice-maker as claimed in claim 26, wherein the air
humidifier is an evaporator.
28. The ice-maker as claimed in claim 27, wherein the evaporator
comprises a heatable water container.
29. The ice-maker as claimed in claim 28, wherein the heatable
water container comprises a wall which is at least partially made
from an electrically conductive plastic.
30. The ice-maker as claimed in claim 26, wherein the evaporator is
configured to heat water contained therein to a maximum of
60.degree. C.
31. The ice-maker as claimed in claim 26, wherein the evaporator
comprises at least one air exit opening through which vapor
generated can escape and thereafter be deflected toward the mold
container.
32. The ice-maker as claimed in claim 26, wherein the evaporator
has a water capacity of not more than 2 cm.sup.3.
33. The ice-maker as claimed in claim 26 and further comprising a
control device for the temporary operation of the air humidifier
during each ice making process.
34. The ice-maker as claimed in claim 33, wherein the control
device is coupled to a timer in order to operate the air humidifier
with a pre-determined delay after a filling of the mold container
with water.
35. The ice-maker as claimed in claim 33, wherein the control
device is coupled to a temperature sensor in order to operate the
air humidifier once the temperature in the air space has dropped
below a pre-determined temperature.
36. The ice-maker as claimed in claim 26, wherein the mold
container and the air humidifier are connected to the same water
supply line.
37. The ice-maker as claimed in claim 26, wherein the air
humidifier is configured to deliver water to the mold container
once a target fill level has been exceeded.
38. The ice-maker as claimed in claim 36, wherein the air
humidifier is arranged in the water supply line upstream of the
mold container.
39. The ice-maker as claimed in claim 26, wherein the mold
container comprises a plurality of ice compartments that are not
mutually connected.
40. The ice-maker as claimed in claim 26 and further comprising a
blower for driving air circulation in the air space.
41. The ice-maker as claimed in claim 40, wherein air guides are
provided which deflect the air stream delivered by the blower at
least partially over the surface of water in the mold
container.
42. A refrigeration appliance comprising: a housing; and an
ice-maker having a mold container configured to be filled with
water and an air space adjacent to a surface of water in the mold
container; and an air humidifier, the air humidifier being operable
to humidify air in the air space above the surface of water in the
mold container to thereby bring the air to a predetermined moisture
level.
43. The refrigeration appliance as claimed in claim 42 and further
comprising a blower that drives air circulation between the air
space and a refrigerant evaporator and thereby cools the air
space.
44. The refrigeration appliance as claimed in claim 43, wherein the
air circulation is weaker over a water surface of the air
humidifier than over the water surface of the mold container.
45. A method for producing ice pieces, the method comprising:
dosing water into a mold container; filling an evaporator; cooling
the water; and applying ice crystals to the water once a
pre-determined inoculation temperature of the water below 0.degree.
C. is reached.
46. The method as claimed in claim 44, wherein the steps of dosing
water into a mold container and filling an evaporator take place
simultaneously and the steps of cooling the water and applying ice
crystals to the water take place sequentially, beginning with the
step of cooling the water.
47. The method as claimed in claim 44, wherein the steps of dosing
water into a mold container, filling an evaporator, cooling the
water, and applying ice crystals to the water take place
sequentially, beginning with the step of dosing water into a mold
container.
48. The method as claimed in claim 45, wherein the ice crystals are
obtained by evaporation of water and cooling the vapor obtained to
below 0.degree. C.
49. The method as claimed in claim 45, wherein the inoculation
temperature lies in the range of -2.degree. C. to -7.degree. C.
50. The method as claimed in claim 45, wherein the evaporation of
water takes place over a time span of 0.5 minutes to 2.5
minutes.
51. The method as claimed in claim 45, wherein the evaporation of
water takes place over a time span of 1 minute to 2 minutes.
Description
[0001] The present invention relates to an ice-maker comprising a
mold container which can be filled with water and which, for
ice-making, can be cooled to a temperature below 0.degree. C., a
refrigeration appliance provided therewith and an ice-making method
which can be carried out, in particular, with an ice-maker of this
type.
[0002] Most conventional ice-makers make use of a mold container in
which a plurality of compartments which, when filled, communicate
with one another, is provided. Examples of ice-makers of this type
are described in DE 4 113 767 C2 and DE 2 429 392 A.
[0003] There are two important reasons for providing a connection
between the compartments of the mold container. Firstly, the
connection facilitates automatic filling of the mold container,
since water can be fed into the mold container at a single site and
can spread out from there into the mutually communicating
compartments. A further reason is the mechanism of ice formation.
Ice formation starts, according to a process known as heterogeneous
nucleation, not at 0.degree. C, but at a few degrees below
0.degree. C. It relies on the presence of heterogeneous, that is
non-aqueous nucleation seeds and if these are lacking, water can be
cooled to -40.degree. C. without freezing. This effect in an
automatically operating ice-maker is undesirable for a variety of
reasons. Firstly, if the compartments do not communicate, there is
a risk that nucleation seeds are lacking in individual
compartments, so that the water therein remains liquid, while in
other compartments it has long since frozen. If the content of the
compartments is emptied into an ice storage container and a
compartment still contains water, the water freezes in the storage
container, so that the finished pieces of ice therein freeze
together into a block that is no longer easily handled. In order to
reduce the probability of this, either a long waiting time must be
allowed for before the emptying of the compartments, in order to
give compartments without efficient nucleation seeds the
opportunity to freeze, which severely reduces the productivity of
the ice-maker, or the ice-maker must be operated at extremely low
temperatures, which can only be maintained with a large energy
input. Conventionally, these problems are circumvented by allowing
the compartments of the mold container to communicate with one
another during freezing, so that ice formation from one compartment
in which an effective nucleation seed enables early freezing
spreads into all the other compartments. In this way, however, only
mutually connected ice pieces can be obtained and these do not
break apart reliably on removal from the mold and therefore take up
a large amount of space in a collecting container and are difficult
to handle.
[0004] The object of the present invention is to provide an
ice-maker, a refrigeration appliance provided therewith and an
ice-making method which function rapidly and efficiently with a
small input of energy.
[0005] This aim is achieved, firstly with an ice-maker comprising a
mold container which can be filled with water and an air space
adjacent to a water surface in the mold container, wherein an air
humidifier is provided to enrich the air over the water surface
with moisture. By this moisture condensing out in the form of tiny
snow flakes, highly efficient nucleation seeds are obtained which
precipitate on the water surface and from there are able to
initiate the ice formation at temperatures only slightly below
0.degree. C.
[0006] In the simplest case, the air humidifier is an
evaporator.
[0007] In order to enable rapid and efficient warming of the water
in the evaporator, a water container of the evaporator preferably
has a wall which is at least partially made from an electrically
conductive plastic which, for heating thereof, has a current
applied thereto.
[0008] In order to prevent deposition of limescale in the
evaporator, said evaporator is preferably configured to heat the
water contained therein to a maximum of 60.degree. C.
[0009] The evaporator has a water capacity of preferably not more
than 2 cm.sup.3 in order firstly to enable rapid heating of the
water contained therein, and secondly to keep low the quantity of
heat emitted to the water in the evaporator and subsequently via
said evaporator to the whole ice-maker.
[0010] A control device is preferably provided for the temporary
operation of the air humidifier during each ice-making process.
[0011] The control device can be coupled to a timer in order to
operate the air humidifier with a pre-determined delay in each case
after filling of the mold container. Alternatively or in addition
thereto, said control device can also be coupled to a temperature
sensor in order to operate the air humidifier once a pre-determined
temperature in the air space has been fallen below.
[0012] The mold container and the air humidifier are suitably
connected to a common water supply line.
[0013] The air humidifier can be configured to deliver water to the
mold container once a target fill level is exceeded. This renders
unnecessary precise dosing of the water quantity fed into the air
humidifier.
[0014] It is expedient, in particular, if the air humidifier is
arranged in the water supply line upstream of the mold
container.
[0015] Since a large number of nucleation seeds is generated with
the snow crystals, the mold container can have a plurality of ice
compartments that are not mutually connected, without a high risk
of the water not freezing in individual compartments. Unconnected
ice pieces are obtained from the unconnected compartments and these
ice pieces can be handled easily and reliably.
[0016] A blower for driving air circulation in the air space is
expediently provided, in order to achieve distribution of the snow
crystals over the whole of the water surface.
[0017] The ice-maker can be provided with a dedicated refrigeration
appliance. The ice-maker is preferably built into a refrigeration
appliance in order to be cooled by the refrigeration unit
thereof.
[0018] The above mentioned blower can also be part of the
refrigeration appliance and, in particular, can serve to drive air
circulation between the air space and a refrigerant evaporator.
[0019] Air circulation of this type serves at the same time to cool
the water in the mold container or contributes at least
substantially to the cooling thereof. In order to prevent the water
in the air humidifier freezing earlier than that in the mold
container, the air circulation over the water surface of the air
humidifier is preferably weaker than that over the water surface of
the mold container.
[0020] The object of the invention is further achieved by a method
for producing ice pieces, in particular in an ice-maker or a
refrigeration appliance, as defined above, comprising the following
steps: [0021] dosing water into a mold container, [0022] cooling
the water, [0023] applying ice crystals to the water when a
pre-determined inoculation temperature of the water below 0.degree.
C. is reached.
[0024] The ice crystals are preferably obtained by evaporation of
water and cooling the vapor thereby obtained to below 0.degree. C.
Inoculation of the water with the ice crystals preferably takes
place at a water temperature of between -2.degree. C. and
-7.degree. C., wherein in the case of ice making in a
thermostatically controlled cooling chamber of a refrigeration
appliance, the inoculation temperature can be selected to be higher
the lower the target temperature of the thermostat regulation is.
The air temperature in the ice-maker is generally lower at the time
of the inoculation and a temperature of -10.degree. C. is
preferable.
[0025] Further features and advantages of the invention are
disclosed by the following description of exemplary embodiments,
making reference to the drawings, in which:
[0026] FIG. 1 shows a schematic section through a refrigeration
appliance with an ice-maker according to the present invention,
[0027] FIG. 2 shows a perspective view of an exemplary embodiment
of the ice-maker according to the invention, and
[0028] FIG. 3 shows a graphical representation of the change in
temperature and air humidity over time during an ice-making
cycle.
[0029] The refrigeration appliance shown in schematic section in
FIG. 1 has a heat-insulating body 1 and a door 2, which delimit an
interior space 3. The interior space 3 is kept by an evaporator,
which is accommodated in the evaporator chamber 4 in the upper
region of the body 1, at a temperature of below 0.degree. C. An
automatic ice-maker 5, which is described below in greater detail
by reference to FIG. 2, is arranged in the immediate vicinity of
the evaporator chamber 4 in the interior space 3, so that cold air
can be efficiently applied to said ice-maker 5 from the evaporator
chamber 4.
[0030] Arranged under the ice-maker 5 is a collecting container 6
of an ice dispenser, said collecting container 6 receiving ice
pieces ejected by the ice-maker 5. The collecting container 6
extends over a large part of the depth of the interior space 3.
Accommodated in a rearward recess 7 of the collecting container 6
is an electric motor for driving a stirring paddle 8 which extends
in the longitudinal direction of the collecting container 6. One
end of the stirring paddle 8 facing away from the recess 7 extends
into a cylindrical dispensing chamber 10. Knives 9 of a grinding
device are fastened to a sleeve surrounding the end of the stirring
paddle 8 and can be coupled via a clutch 11 to the rotation of the
stirring paddle 8. A second group of knives 12 can be fixed to the
cylindrical outer wall of the dispensing chamber 10, so that the
knives 9, when they are carried along by the rotation of the
stirring paddle 8, each leave intermediate spaces between the
knives 12 and thus chop the ice pieces conveyed out of the
collecting chamber 8 into the dispensing chamber 10 before said ice
pieces fall out of the dispensing opening 13 into the lower region
of the dispensing chamber 10. The locking of the knives 12 to the
wall of the dispensing chamber 10 is releasable, so that the knives
12 are carried along by the rotation of the knives 9, with the
result that the intact ice pieces are dispensed from the dispensing
opening 13. When the clutch 11 is open, neither the knives 9 nor
the knives 12 are carried along by the rotation of the stirring
paddle 8. In that the stirring paddle 8 is automatically rotated
from time to time with the clutch 11 open, it is possible to
prevent freezing together of ice pieces in the collecting container
6 and to keep them movable so that, when required, they can be
reliably dispensed through the dispensing opening 13.
[0031] The dispensing opening 13 lies opposed to a channel 14,
which extends through an insulating material layer of the door 2
and opens into a recess 15 which is open toward the outside of the
door 2. A flap 16 holds the channel 14 closed for as long as the
dispenser is not in operation, which means that the stirring paddle
8 rotates with the clutch 11 closed, in order to dispense ice
through the dispensing opening 13 and the channel 14 into a
container placed in the recess 15.
[0032] A water tank 17 is embedded in the rear wall of the recess
14 in the insulating material of the door 2. The water tank 17 is
connected, on one side, like the ice-maker 5, via a supply line 18
and a shut-off valve 19 to the drinking water mains and, on the
other side, to a supply point 20 in the recess 15.
[0033] A detailed description of the ice-maker 5 follows, making
reference to FIG. 2. The figure shows an injection-molded
rectangular frame 21 made from plastics, in which a mold container
22 with, in this case, seven compartments 23 is suspended pivotable
about a longitudinal axis 24. A motor and a gearbox for driving a
pivot movement of the mold container 22 about the longitudinal axis
24 are, respectively, accommodated in two hollow wall parts 25, 26
of the frame 21. In the orientation shown, separating walls 27 are
arranged between the compartments 23 of the mold container,
abutting one side.
[0034] Fastened above the mold container 22 on the wall part 26 is
a small flat tray 28. A hollow web 29, which can be equipped with
an electrical heating rod 30 from the side of the wall part 26, is
provided on the base of the tray. Alternatively, the tray 28 itself
or a part thereof can also be formed from a plastic which is made
electrically conductive with a suitable additive material, such
that said tray can be heated by passing a current through it. The
supply line 18 opens into the tray 28. A plurality of broad
cut-outs 31, 32 is formed in the side walls of the tray 28. Pillars
33 are left between the cut-outs 31, 32 in order to carry a cover
34. Formed at the deepest cut-out, identified as 32, is an overflow
lip 35 via which the water can flow out of the tray 28 into the
mold container 22. The capacity of the tray 28 is substantially
less than that of the mold container 22, at only a few cm.sup.3,
more particularly less than 1 cm.sup.3.
[0035] At the start of the ice making cycle, the shut-off valve 19
which supplies the ice-maker 5 is temporarily opened in order to
let water in. The water flows into the tray 28 and passes via the
overflow lip 35 into the mold container 22. The quantity of water
fed in is dosed so that it just suffices to flow over the
separating walls 27 at their lower-lying end. This ensures even
filling of all the compartments 23 of the mold container 22. The
mold container 22 is then slightly rotated clockwise about the axis
24 until the upper edges of the separating walls 27 are horizontal
and lie higher than the water surface in the compartments 23, so
that the water portions in the compartments 23 are separated from
one another.
[0036] In this position, the water in the compartments 23 is
cooled. A temperature sensor (not shown) is provided in order to
monitor the temperature of the water and to communicate it to a
control circuit (not shown). The temperature sensor can be placed
directly at the mold container in order to detect the actual
temperature of the water in the compartments 23. It is also
conceivable to place said sensor at another site, for example, at
the frame 21, so that it detects the temperature of the air in the
ice-maker, although then the control circuit is designed to
estimate the water temperature based on the measured air
temperature and the cooling time. The control circuit can be a
central control circuit of the refrigeration appliance which is
also responsible for the temperature regulation of the interior
space 3, or it may be a dedicated control circuit of the ice-maker
5.
[0037] While the water in the compartments 23 cools, the heating
rod 30 can be operated at a low power level sufficient to prevent
freezing of the water in the tray 28. If the water temperature in
the compartments 23 detected by the sensor or estimated by the
control circuit drops below a pre-determined limit value, the
control circuit switches the power of the heating rod 30 to high in
order to heat the water in the tray 28. The limit value is
typically selected to lie within the temperature interval from
-6.degree. C. to -3.degree. C. Particularly if the same control
circuit is responsible for the control of the ice-maker 5 and for
the temperature regulation of the interior space 3, the limit value
can expediently be pre-determined as a function of the target
temperature of the internal space 3.
[0038] Due to the heating, some of the water in the tray 28
evaporates and water vapor passes out through the cut-outs 31, 32.
The power of the heating rod 30 is controlled such that the water
in the tray 28 is not heated above 60.degree. C., in order to
prevent limescale forming on the walls of the tray 28. This water
vapor forms a fine mist of snow or ice crystals, which is
distributed over the mold container 22 by the draught prevailing
due to the air exchange with the evaporator chamber 4. Thus
crystals which serve as nucleation seeds are reliably distributed
to each compartment 23 and initiate the ice formation there.
[0039] Due to the ice formation, heat is released. The above
mentioned dependency of the temperature limit value on the target
temperature of the interior space 3 is suitable for preventing this
heat from leading to re-thawing of the previously formed ice in the
compartments 23. Given a low target temperature and a
correspondingly low temperature of the air fed out of the
evaporator chamber 4, the heat released during ice formation can be
rapidly conducted away, so that the temperature in the compartments
23 also does not reach 0.degree. C. again when the inoculation with
snow crystals has already been carried out at a relatively high
water temperature in the compartments 23 of -3.degree. C. In the
case of a relatively high target temperature of the interior space
of, for example, -14.degree. C., the heat released on ice formation
cannot be conducted away so rapidly, so that it is suitable to
carry out the inoculation at a lower water temperature in the
compartments 23 of approximately -6.degree. C.
[0040] Since it can be assumed with certainty that, following
inoculation with the snow crystals, ice formation has taken place
in each individual compartment 23, the time between the inoculation
and a subsequent emptying of the compartments 23 can be made
relatively short, so that the compartments are soon available again
for refilling.
[0041] In order to facilitate emptying, the mold container 22 is
provided at a base side (not shown in FIG. 2) with an electrical
heater. Once, following inoculation, a time period sufficient for
complete freezing has elapsed, the control circuit activates the
heater in order to melt the ice pieces in the compartments 23 at
their surface and then activates the motor in order to rotate the
mold container 22 about the longitudinal axis 24, inverting it so
that the ice pieces fall out of the compartments 23 into the
collecting container 26 placed beneath.
[0042] As the mold container 22 is rotated in the same direction,
the position shown in FIG. 2 is reached again and a new ice making
cycle can begin again with the filling of the compartments 23.
[0043] FIG. 3 shows, by way of example, the variation of the water
temperature in the compartments 23, the water temperature in the
tray 28 and the air humidity in the ice-maker during an ice making
cycle. The temperature in the compartments 23 is represented by the
continuous line 36 and the associated temperature scale is shown on
the left side of the graph, while the percentage air humidity is
shown as a dashed line 37 and the temperature of the tray 28 is
shown as a dot-dashed line 38, a scale for both (in percent and
degrees Celsius) is shown at the right side of the graph. The
working cycle begins at approximately 18:30 with the filling of the
mold container 22. The temperature of said mold container 22 is
approximately 9.degree. C. at this point in time, since it has
previously been heated in order to eject the ice pieces from the
preceding cycle. The tray 28 is warmed to approximately 0.degree.
C. by the feeding in of fresh water. The air humidity is at a
temporary maximum due to the heating of the mold container 22.
[0044] During the following 12 minutes, the mold container 22 cools
significantly faster than the tray 28 and reaches a temperature of
-4.degree. C. The more rapid cooling of the mold container 22 is
mainly a consequence of the air fed into the ice-maker 5. By means
of suitable placement of air channels, deflector plates or the like
in the ice-maker 5, it is ensured that the overwhelming majority of
the cold air flowing through the ice-maker 5 flows along, and
cools, the mold container 22, while the flow rate in the vicinity
of the tray 28 is kept substantially less. The use of an
effectively heat-conducting material, such as aluminum, and the
mounting of cooling ribs on the underside (not shown in FIG. 2) of
the mold container 22 also ensures rapid heat exchange, whereas the
tray 28 is preferably made from a poorly heat-conducting plastic
and the cover 34 placed thereover ensures that only a weak air flow
passes through the cut-outs 31 and over the surface of the water in
the tray 28. It can also be provided, as stated above, that the
heater rod 30 of the tray 28 is also in operation during the
cooling phase at a low power level that is set to be just
sufficient in order to prevent freezing of the water in the tray
28.
[0045] As the limit temperature is detected at approximately 18:41,
the control circuit switches the heating rod 30 to a high power, so
that the tray 28 is heated to approximately 50.degree. C. within a
minute. Water vapor which forms in the protected space between the
water surface of the tray 28 and the cover 34 is flushed out of the
cut-outs 31, 32 and is distributed in the air space over the mold
container 22. The air humidity curve 37 reaches a maximum again.
The snow crystals thereby formed initiate the ice formation,
leading to a marked rise in the temperature of the mold container
22 to approximately -1.degree. C. A cooling phase lasting
approximately half an hour follows until, at approximately 19:15,
the heater in the mold container 22 is started and the mold
container is inverted in order to eject the finished ice
pieces.
[0046] Since the tray 28 is heated only very briefly, the quantity
of energy required is small. Assuming 25 ice making cycles per day,
a heating power of 50 Watt, and a heating duration of 70 seconds in
each case, the daily energy requirement is 0.024 kWh. The
productivity of the ice-maker that can be achieved with this
measure with a temperature in the interior space 3 of -14.degree.
C. is higher than that of a conventional ice-maker without
inoculation, which is operated at -18.degree. C. The energy saving
achievable thereby exceeds the energy expenditure for the water
vapor production by many orders of magnitude.
* * * * *