U.S. patent application number 12/379694 was filed with the patent office on 2009-09-10 for method of controlling ice making assembly for refrigerator.
Invention is credited to Young Jin Kim, Ho Youn Lee, Tae Hee Lee, Joon Hwan Oh, Hong Hee Park.
Application Number | 20090223230 12/379694 |
Document ID | / |
Family ID | 40791004 |
Filed Date | 2009-09-10 |
United States Patent
Application |
20090223230 |
Kind Code |
A1 |
Kim; Young Jin ; et
al. |
September 10, 2009 |
Method of controlling ice making assembly for refrigerator
Abstract
Provided is a method of controlling an ice making assembly for a
refrigerator. According to the method, transparent ice can be made
in an ice making space which is kept at a temperature lower than
0.degree. C.
Inventors: |
Kim; Young Jin; (Seoul,
KR) ; Lee; Tae Hee; (Seoul, KR) ; Park; Hong
Hee; (Seoul, KR) ; Lee; Ho Youn; (Seoul,
KR) ; Oh; Joon Hwan; (Seoul, KR) |
Correspondence
Address: |
MCKENNA LONG & ALDRIDGE LLP
1900 K STREET, NW
WASHINGTON
DC
20006
US
|
Family ID: |
40791004 |
Appl. No.: |
12/379694 |
Filed: |
February 26, 2009 |
Current U.S.
Class: |
62/73 |
Current CPC
Class: |
F25C 1/08 20130101; F25C
2600/04 20130101; F25C 1/18 20130101; F25B 2600/11 20130101; F25C
5/08 20130101 |
Class at
Publication: |
62/73 |
International
Class: |
F25C 5/08 20060101
F25C005/08 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 10, 2008 |
KR |
10-2008-0021817 |
Claims
1. A method of controlling an ice making assembly for a
refrigerator, the method comprising: initiating an ice making mode;
supplying water to an ice recess formed in a tray, the tray ready
to receive a rod; contacting the water with the rod to remove heat
from the water; intermittently operating a heater disposed at the
tray to maintain the tray at a temperature above freezing; and
controlling the operation of a cooling fan to selectively supply
cooling air to the rod.
2. The method according to claim 1, wherein an ice ejecting heater
is maintained in a turned-off state until an ice making operation
is completed, and is turned on for an ice ejecting operation.
3. The method according to claim 1, wherein the cooling fan is
selectively turned on and off to maintain the rod at a
predetermined temperature during an ice making operation.
4. The method according to claim 1, wherein a rotation speed of the
cooling fan is increased or decreased to maintain the rod at a
predetermined temperature while ice is forming in the ice tray.
5. The method according to claim 1, wherein a temperature of the
rod is steadily and continuously decreased during an ice making
operation.
6. The method according to claim 1, wherein a temperature of the
rod is decreased in a step-wise manner during an ice making
operation.
7. The method according to claim 1, wherein a temperature of the
rod is maintained at a temperature below freezing while the
temperature of the tray is maintained at a temperature above
freezing.
8. A method of controlling an ice making assembly for a
refrigerator, the method comprising: initiating an ice making mode;
supplying water to an ice recess formed in a tray, the tray ready
to receive a rod; contacting the water with the rod to remove heat
from the water; intermittently operating a heater disposed at the
tray to maintain the tray at a temperature above freezing; and
controlling an operation of an ice ejecting heater, which heats the
rod, so as to gradually decrease a temperature of the rod.
9. The method according to claim 8, wherein a cooling fan is set to
run until an ice making operation is completed.
10. The method according to claim 8, wherein the ice ejecting
heater is selectively turned on and off to maintain the rod at a
predetermined temperature while ice is forming.
11. The method according to claim 8, wherein a voltage applied to
the ice ejecting heater is increased or decreased to maintain the
rod at a predetermined temperature while ice is forming.
12. The method according to claim 11, wherein the voltage applied
to the ice ejecting heater is increased or decreased by a
semiconductor switch device.
13. The method according to claim 8, wherein a temperature of the
rod is steadily and continuously decreased during an ice making
operation.
14. The method according to claim 8, wherein a temperature of the
rod is decreased in a step-wise manner during an ice making
operation.
15. A method of controlling an ice making assembly for a
refrigerator, the method comprising: initiating an ice making mode;
supplying water to an ice recess formed in a tray, the tray ready
to receive a rod; contacting the water with the rod to remove heat
from the water; intermittently operating a heater disposed at the
tray to maintain the tray at a temperature above freezing; and
operating an ice ejecting heater, to heat the rod, cooperatively
with a cooling fan to circulate cool air controlling the operation
of the ice ejecting heater and the cooling fan to gradually
decrease a temperature of the rod.
16. The method according to claim 15, wherein if the rod has a
temperature equal to or greater than a predetermined temperature,
the cooling fan is turned on and the ice ejecting heater is turned
off.
17. The method according to claim 15, wherein if the rod has a
temperature lower than a predetermined temperature, the cooling fan
is turned off and the ice ejecting heater is turned on.
18. The method according to claim 15, wherein if the rod has a
temperature equal to or greater than a predetermined temperature, a
rotation speed of the cooling fan is increased, and a voltage
applied to the ice ejecting heater is decreased.
19. The method according to claim 15, wherein if the rod has a
temperature lower than a predetermined temperature, a rotation
speed of the cooling fan is decreased, and a voltage applied to the
ice ejecting heater is increased.
20. The method according to claim 18, wherein a voltage applied to
the ice ejecting heater is increased or decreased by a
semiconductor switch device.
21. The method according to claim 19, wherein a voltage applied to
the ice ejecting heater is increased or decreased by a
semiconductor switch device.
22. The method according to claim 15, wherein the temperature of
the rod is steadily and continuously decreased during an ice making
operation.
23. The method according to claim 15, wherein the temperature of
the rod is decreased in a step-wise manner during an ice making
operation.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application claims priority under 35 U.S.C. 119
and 35 U.S.C. 365 to Korean Patent Application No. 10-2008-0021817,
filed Mar. 10, 2008, which is hereby incorporated by reference in
its entirety.
BACKGROUND
[0002] The present disclosure relates to a method of controlling an
ice making assembly for a refrigerator for making transparent
ice.
[0003] Refrigerators are domestic appliances used for storing foods
in a refrigerated or frozen environment.
[0004] Recently, various kinds of refrigerators have been
introduced into the market. Examples of recent refrigerators
include: a side-by-side type refrigerator in which a refrigerator
compartment and a freezer compartment are disposed in the left and
right sides; a bottom-freezer type refrigerator in which a
refrigerator compartment is disposed above a freezer compartment;
and a top-mount type refrigerator in which a refrigerator
compartment is disposed under a freezer compartment.
[0005] Furthermore, many of recently introduced refrigerators have
a structure that allows a user to access food or drink disposed
inside a refrigerator compartment through an alternate access point
without having to open a primary refrigerator compartment door. A
compressor, a condenser, and an expansion member are disposed
inside a refrigerator, and an evaporator is disposed on the
backside of a refrigerator main body, as refrigeration-cycle
components of the refrigerator.
[0006] In addition, an ice making assembly can be provided inside
the refrigerator. The ice making assembly may be mounted in a
freezer compartment, a refrigerator compartment, a freezer
compartment door, or a refrigerator compartment door.
[0007] To satisfy consumers' increasing demands for transparent
ice, much research has been conducted on ice making assemblies that
can provide transparent ice.
SUMMARY
[0008] The disclosed embodiments provide a method of controlling an
ice making assembly for a refrigerator that can produce transparent
ice.
[0009] The disclosed embodiments provide methods of controlling an
ice making assembly for a refrigerator.
[0010] In one embodiment, there is provided a method of controlling
an ice making assembly for a refrigerator, the method including:
selecting an ice making mode; supplying water to an ice recess
formed in a tray so as to immerse a rod configured to take heat
from the water; intermittently operating a heater disposed at the
tray to maintain the tray at a temperature higher than a freezing
temperature; and controlling an operation of a cooling fan
configured to supply cooling air so as to cool the rod.
[0011] In another embodiment, there is provided a method of
controlling an ice making assembly for a refrigerator, the method
including: selecting an ice making mode; supplying water to an ice
recess formed in a tray so as to immerse a rod configured to take
heat from the water; intermittently operating a heater disposed at
the tray to maintain the tray at a temperature higher than a
freezing temperature; and controlling an operation of an ice
ejecting heater configured to heat the rod so as to decrease a
temperature of the rod with time.
[0012] In another embodiment, there is provided a method of
controlling an ice making assembly for a refrigerator, the method
including: selecting an ice making mode; supplying water to an ice
recess formed in a tray so as to immerse a rod configured to take
heat from the water; intermittently operating a heater disposed at
the tray to maintain the tray at a temperature higher than a
freezing temperature; and controlling cooperative operations of an
ice ejecting heater configured to heat the rod and a cooling fan
configured to supply cooling air so as to decrease a temperature of
the rod with time.
[0013] According to the method of controlling the ice making
assembly, transparent ice can be made in an ice making compartment
that is kept at a temperature lower than 0.degree. C.
[0014] That is, the tray is kept at a temperature higher than
0.degree. C. during an ice making operation to freeze water slowly
and to ensure that the water freezes in a direction starting from
the rod toward the inner surface of the ice recess. Therefore,
while the freezing of the water proceeds, air dissolved in the
water can escape from the water before the air is trapped in the
ice. The resulting ice that is made is thus transparent.
[0015] Furthermore, during an ice making operation, the temperature
of water may be adjusted by controlling the cooling fan and the
temperature of the freezing rod so that bubbles contained in the
water can escape during the ice making operation. Transparent ice
can be readily made.
[0016] The details of one or more embodiments are set forth in the
accompanying drawings and the description below. Other features
will be apparent from the description and drawings, and from the
claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] FIGS. 1 and 2 are perspective views illustrating an ice
making assembly structure for a refrigerator according to an
embodiment of the invention.
[0018] FIG. 3 is a perspective view illustrating an ice making
assembly according to an embodiment of the invention.
[0019] FIG. 4 is a perspective view illustrating the ice making
assembly, according to an embodiment of the invention, just before
ice is transferred to a container.
[0020] FIG. 5 is a perspective view illustrating a tray of the ice
making assembly according to an embodiment of the invention.
[0021] FIG. 6 is a sectional view illustrating a process of making
transparent ice in the ice making assembly according to an
embodiment of the invention.
[0022] FIG. 7 is a flowchart depicting a method of controlling the
temperature of a tray of an ice making assembly according to an
embodiment of the invention.
[0023] FIG. 8 is a flowchart depicting a method of making
transparent ice using an ice making assembly according to a first
embodiment of the invention.
[0024] FIG. 9 is a flowchart depicting a method of making
transparent ice using an ice making assembly according to a second
embodiment of the invention.
[0025] FIG. 10 is a flowchart depicting a method of making
transparent ice using an ice making assembly according to a third
embodiment of the invention.
[0026] FIG. 11 is a graph illustrating the temperature of a rod
when a method of controlling an ice making assembly is performed
according to an embodiment of the invention.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0027] Hereinafter, an ice making assembly for a refrigerator will
be described in detail according to embodiments of the present
disclosure with reference to the accompanying drawings,
[0028] In the following description, an ice making assembly may be
mounted at a freezer compartment door. However, the ice making
assembly can be mounted at other places such as a freezer
compartment, a refrigerator compartment, and a refrigerator
compartment door and still be within the scope of the
invention.
[0029] FIGS. 1 and 2 are perspective views illustrating an ice
making assembly structure for a refrigerator according to an
embodiment of the invention.
[0030] Referring to FIGS. 1 and 2, an ice making assembly 20 of the
exemplary embodiment may be mounted on the backside of a door 10,
and the backside of the door 10 may be recessed to form an ice
making space 11 that accommodates the ice making assembly 20. A
cooling air supply hole 111 (FIG. 2) may be formed at a side of the
ice making space 11 to allow inflow of cooling air from an
evaporator (not shown), and a cooling air discharge hole 112 (FIG.
2) may be formed in the side of the ice making space 11 to allow
the cooling air from the ice making space 11 to flow back to the
evaporator.
[0031] In detail, the ice making assembly 20 may be mounted at an
upper portion of the ice making space 11, and a container 30 may be
mounted under the ice making assembly 20 to store ice made by the
ice making assembly 20. The ice making assembly 20 may be protected
by an ice making cover 31. The ice making cover 31 may also provide
guidance for the ice separated from the ice making assembly 20 so
that it follows a path directly to the container 30.
[0032] FIG. 3 is a perspective view illustrating the ice making
assembly 20 according to an embodiment of the invention, and FIG. 4
is a perspective view illustrating the ice making assembly 20,
according to an embodiment of the invention, just before ice is
transferred to the container 30.
[0033] Referring to FIGS. 3 and 4, the ice making assembly 20 may
include: a tray 21 having a plurality of ice recesses 211 for
making ice in a predetermined shape; a plurality of fins 24 stacked
above the tray 21 and capable of vertical and rotational movement;
a plurality of rods 23 configured to be inserted into the ice
recesses 211 through the fins 24; an ice ejecting heater 25 may be
provided as the lowermost fin of the plurality of fins 24; a
supporting plate 27 configured to support the ice ejecting heater
25, the remainder of the plurality of fins 24, and the rods 23 as
one unit; a water supply part 26 disposed at an end of the tray 21;
and a control boxy 28 disposed at another end of the tray 21.
[0034] In detail, a heater (not shown) may be mounted at the bottom
of the tray 21 to maintain the temperature of the tray 21 at a
temperature above freezing. A supporting lever 271 may extend from
a front end of the supporting plate 27, and a hinge 272 may be
disposed at an end of the supporting plate 27. During an ice making
operation, as shown in FIG. 4, ice cubes (I) having a shape
corresponding to the shape of the ice recesses 211 are formed
around the rods 23.
[0035] A cam 29 coupled to a driving motor are disposed inside the
control box 28. The driving motor drives a rotational movement of
the cam 29. The hinge 272 may be coupled to the cam 29 so that the
hinge 272 can be lifted and rotated by the rotation of the cam 29.
The ice ejecting heater 25 may have a plate-like shape and may make
contact with the rods 23. Alternatively, the ice ejecting heater 25
may be buried in the rods 23. The supporting plate 27 may act to
close an open-top of the tray 21 (see FIG. 3) such that water
supplied to the tray 21 is indirectly cooled by cooling air that is
supplied to the ice making space 11 and flows about fins 24 and
rods 23.
[0036] Hereinafter, ice making and ice ejecting operations of the
ice making assembly 20 will be described.
[0037] First, the heater attached to the tray 21 may be operated to
maintain the tray 21 at a temperature higher than 0.degree. C. so
as to make transparent ice in the ice making assembly 20.
[0038] In the related art when water is rapidly frozen by cooling
air supplied from an evaporator, air dissolved in the water cannot
escape from the water before it freezes. Thus, when water is frozen
together with gas that is trapped inside the water, the resulting
ice will not be transparent.
[0039] However, in the ice making assembly 20 of the disclosed
exemplary embodiments, the tray 21 may be kept at a temperature
above freezing so that the water freezes slowly. The air in the
water is then able to escape before the water is completely frozen.
Thus resulting in transparent ice, which is preferred by the user.
Once the rods 23 are inserted in the ice recesses 21 1 of the tray
2 1, water is supplied to the tray 2 1, and a freezing operation is
started after the supply of water is completed. The freezing
operation is started by supplying cooling air to the ice making
space 1 1. Then, the temperature of the fins 24 is reduced to below
freezing by convection heat transfer with the supplied cooling air.
The temperature of the rods 23 is also reduced to below freezing by
conduction heat transfer with the fins 24. Portions of the rods 23
inserted in the ice recesses 21 1 are submerged in the water.
Therefore, the water may be gradually frozen starting from a region
closest to the rods 23, and the frozen region of the water becomes
attached to the rods 23. Then, the freezing of the water further
proceeds outwardly from a region closest to the rods 23 toward a
region close to the inner surfaces of the ice recesses 211.
[0040] After the water is completely frozen, the cam 29 is rotated
to move the rods 23, and the ice cubes formed thereon, vertically
upward out of the ice recesses 211. In the exemplary embodiment,
after the ice cubes (I) are completely removed from the ice
recesses 211, the cam 29 is further rotated to rotate the rods 23
at a predetermined angle so that the ice cubes (I) can slip off of
the rods 23 and fall into an ice container 30.
[0041] Whether freezing of the water is completed may be determined
by several methods. A first method involves monitoring time lapsed
while the water is freezing. If a predetermined amount of time
passes after the start of the freezing, it may be determined that
the freezing is completed.
[0042] Another method of determining the completion of freezing
involves lifting the rods 23, via cam 29, out of the recesses 211,
and detecting an amount of water remaining in the recesses 211. The
rods 23 may be lifted to a predetermined height after a
predetermined amount of time has passed from the start of freezing.
The predetermined height may be a height at which ice attached to
the rods 23 is not yet fully separated from the ice recesses 211.
Once the rods 23 are lifted, the amount of water remaining in the
ice recesses 21 may be detected. The amount of unfrozen water
remaining in the ice recesses 211 can be detected, for example,
using a water level sensor (not shown) mounted on the tray 21. If
the amount of unfrozen water remaining in the ice recesses 211 is
equal to or less than a predetermined amount, it may be determined
that the freezing is completed. On the other hand, if the amount of
unfrozen water remaining in the ice recesses 211 is greater than
the predetermined amount, the rods 23 may be moved down to their
original positions to continue freezing the water. The water sensor
will be described later with reference to the accompanying
drawings.
[0043] As described above, after the freezing of the water is
completed, the cam 29 may be rotated such that it moves the rods
23, and the ice cubes formed thereon, vertically upward out of the
ice recesses 211. After ice cubes (I) are completely removed from
the ice recesses 211, the cam 29 may be further rotated to effect
rotation of the rods 23. More specifically, the hinge 272 may be
rotated by the cam 29 to rotate the rods 23 at a predetermined
angle. Once the rods 23 are rotated to a predetermined angle as
shown in FIG. 4, the ice ejecting heater 25 may be operated. When
the ice ejecting heater 25 is operated, the temperature of the rods
23 is increased, and thus the ice cubes (I) are separated from the
rods 23. The separated ice cubes (I) may thus fall into the
container 30.
[0044] FIG. 5 is a perspective view illustrating the tray 21 of the
ice making assembly 20 according to an embodiment of the
invention.
[0045] As illustrated in FIG. 5, the ice recesses 211 are arranged
in the tray 21 of the ice making assembly 20. Grooves 213 having a
predetermined depth are formed between the ice recesses 211. Water
can travel between neighboring ice recesses 211 through the grooves
213. Bottoms of the grooves 213 are spaced apart from bottoms of
the ice recesses 211.
[0046] A guide 212 may be formed at an end portion of the tray 21
to guide water supplied from the water supply part 26 to the tray
21 and to the ice recesses 211. Water may be supplied to the ice
recesses 211 closest to the guide 212 and may gradually travel to
the ice recess 211 farthest from the guide 212.
[0047] A water level sensor 40 may be mounted at a side of the ice
recess 211 farthest from the guide 212, e.g., at a side of the ice
recess located at an end of the tray 21 opposite to the guide 212.
Further, a temperature sensor 50 may be mounted at a side of the
tray 2 1. The temperature sensor 50 may provide feedback to a
subsystem adapted to maintain the tray 21 at a constant
temperature. A tray heater (not shown) may be installed at the tray
21. The tray heater may be installed at the tray 21 in an embedded
or attached manner.
[0048] FIG. 6 is a sectional view illustrating a process of making
transparent ice in the ice making assembly 20 according to an
embodiment of the invention.
[0049] Referring to FIG. 6, in the exemplary embodiment, a tray
heater 60 may be installed in the tray 21 of the ice making
assembly 20. After the rod 23 is moved down to a preset position,
the ice recess 211 is filled with water. Alternatively, the rod 23
can be moved down to the preset position after the ice recess 211
is filled with water.
[0050] Once the rods 23 are in position, and the ice recesses
contain a sufficient volume of water, an ice making operation can
begin. The fins 24 are cooled by cooling air that is circulated to
cool the tray 21 and rods 23 to below freezing by convection heat
exchange with the fins 24. When the temperature of the rod 23 drops
below freezing, ice is formed around the rod 23. At this point, the
tray heater 60 operates to maintain the tray 21 at a temperature
above 0.degree. C. According to an exemplary embodiment, the tray
21 may be kept at a temperature in the range of 1.degree. C. to
2.degree. C. According to Henry's Law, the solubility of gas in
water is reduced as the temperature of the water increases.
Therefore, air present in the water can be removed from the water
as it freezes by operating the tray heater 60. At the same time,
ice grows from the surface of the rod 23.
[0051] During the ice making process, ice forms outwardly from the
surface of rod 23 while the tray 21 is kept at a temperature above
freezing. Therefore, ice cannot form at the inner surface of the
tray 21. In other words, ice cannot form on the inner surface of an
ice recess 211. Accordingly, when the ice making operation is
completed a predetermined amount of water may remain in the ice
recess 211. The removal of the ice cubes from the tray 21 is
facilitated in an embodiment where water remains in an unfrozen
state just adjacent to the inner surface of the ice recess 211.
[0052] A rod temperature sensor 70 may be disposed in the rod 23.
Thus, when the rod 23 is heated by the ice ejecting heater 25 (FIG.
4) during an ice ejecting operation, the temperature increase of
the rod 23 can be controlled to reach a set temperature. It is also
envisioned that during an ice making operation, the rod 23 may be
heated to temporarily increase the temperature of water present in
the tray 21, so as to allow air trapped in the water to escape.
[0053] Other methods are within the scope of the invention. For
example, in another method, a cooling fan (not shown), configured
to supply cooling air to the inside of the ice making space 11, may
be controlled. In yet another method, the ice ejecting heater 25,
configured to heat the rod 23, and the cooling fan may be both
simultaneously operated and controlled. A method of controlling the
temperature of water filled in the tray 21 for making transparent
ice will now be described with reference to a flowchart.
[0054] FIG. 7 is a flowchart depicting a method of controlling the
temperature of a tray of an ice making assembly according to an
embodiment of the invention
[0055] Referring to FIG. 7, an ice making mode may be started by a
user or a control unit (see e.g., ref 45 of FIG. 3) associated with
the refrigerator (operation S11) in general or the ice making
assembly in particular.
[0056] By way of example, the ice making mode can be initiated by
the control unit 45 when an automatic ice making operation is
necessary; for example, when a low amount of ice in ice container
30 is detected.
[0057] After the ice making mode begins, or even continuously, the
control unit 45 receives a signal from a temperature sensor, such
as temperature sensor 50 of FIG. 5, to determine the temperature of
the tray 21. The control unit 45 may determine whether the
temperature T of the tray 21 is at a predetermined temperature
T.sub.0. For example, the control unit 45 may determine whether the
tray temperature T is lower or higher than the predetermined
temperature T.sub.0 (operation S12).
[0058] If the tray temperature T is lower than the predetermined
temperature T.sub.0, the tray heater 60 may be turned on to heat
the tray 21 (operation S13). On the other hand, if the tray
temperature T is equal to or greater than the predetermined
temperature T.sub.0, the tray heater 60 may be turned off
(operation S14). Here, turning-off of the tray heater 60 includes
the case where the tray heater 60 is previously turned off and kept
in the turned-off state.
[0059] As the tray heater 60 is controlled as described above, the
control unit 45 may also determine whether ice making is completed
(operation S15). An exemplary method of determining whether ice
making is complete is as discussed above.
[0060] If it is determined that ice making is complete, the ice
making mode is turned off (operation S16) to complete the ice
making operation. On the other hand, if it is determined that ice
making is not completed, operations S12, S13, and S14 may be
repeated. Thus, the on-off control of the tray heater 60 continues
until the ice is satisfactorily formed.
[0061] By using the above-described control method, the tray 21 can
be kept at a temperature above freezing temperature while ice is
forming around the control rod 23, thus resulting in transparent
ice.
[0062] FIG. 8 is a flowchart depicting a method of making
transparent ice using an ice making assembly according to a first
embodiment of the invention. Referring to FIG. 8, in the exemplary
embodiment, the temperature of water supplied to the tray 21 is
controlled by controlling the operation of a fan during an ice
making operation.
[0063] In detail, according to the above-described gas solubility
properties, air contained in water may be trapped in the water as
it freezes if the temperature of the water drops too quickly. To
prevent this, the temperature of the water is temporarily raised to
allow the air to escape.
[0064] First, when an ice making mode is turned on (operation S2
1), water is first supplied (operation S22). Before an ice making
operation begins after the water supply operation, a control unit
45 determines whether the measured temperature T of the rod 23 is
equal to or greater than a first predetermined temperature T1
(operation S24). Here, the temperature T of the rod 23 may be the
surface temperature of the rod 23, which may be detected using the
rod temperature sensor 70 (FIG. 6). If it is determined that the
temperature T of the rod 23 is equal to or greater than the first
temperature T1, the cooling fan may be turned on to lower the
temperature of rod 23 (operation S25). On the other hand, if it is
determined that the temperature T of the rod 23 is lower than the
first temperature T1, the cooling fan may be turned off (operation
S26) to prevent cool air circulation in the ice making space 11.
Here, turning-on (S25) or turning-off (S26) includes the situation
where the cooling fan may be previously turned on or off and is
maintained in the turned-on or turned-off state, respectively. For
example, if it is determined that the rod temperature T is equal to
or greater than the first temperature T1 and the cooling fan is in
an turned-on state, the cooling fan may simply be left in the
turned-on state.
[0065] Once the cooling fan operation has been determined, the
control unit determines whether ice making time (t) has reached a
first set time t1 (operation S27). 10068J In detail, if it is
determined that the ice making time, e.g., the time passed since
the ice-making operation began (t), has not reached the first set
time t1, the procedure may go back to operation S24. On the other
hand, if it is determined that the ice making time (t) has reached
the first set time t1, the rod 23 temperature may then be
controlled.
[0066] More specifically, after the ice making time reaches the
first set time t1, it is then determined whether the rod
temperature T is equal to or greater than a second predetermined
temperature T2 (operation S28). The second predetermined
temperature T2 may be lower than the first predetermined
temperature T1. If it is determined that the rod temperature T is
equal to or greater than the second temperature T2, the cooling fan
may be turned on (operation S29). Otherwise, the cooling fan may be
turned off (operation S30). These operations are generally the same
as those operations using the first temperature.
[0067] While keeping the rod temperature T below the second
temperature T2, it is determined whether the ice making time (t)
has reached a second set time t2 (operation S31).
[0068] When it is determined that the ice making time (t) reaches
the second set time t2, an ice ejecting operation may be performed
(S32). After the ice ejecting operation, the ice making mode may be
turned off (operation S33). If the ice making time (t) has not
reached the second set time t2, the procedure will go back to
operation S28.
[0069] In the first embodiment, a control process may be carried
out to make transparent ice using the cooling fan without turning
on the ice ejecting heater 25. While the "on/off" control of the
cooling fan is discussed above, the speed of the cooling fan can
also be controlled depending on the measured temperature of the rod
23. In this situation, a variable speed fan motor may be used.
[0070] The temperature of the rod 23 may be reduced slowly, in
steps, to prevent trapping air in the water as it freezes. In the
exemplary embodiment the temperature T of the rod 23 is reduced in
two steps, however, three or more steps may be used according to,
for example, freezer compartment conditions.
[0071] FIG. 9 is a flowchart depicting a method of making
transparent ice using an ice making assembly according to a second
embodiment.
[0072] Referring to FIG. 9, in the exemplary embodiment, the
temperature of water supplied to the tray 21 may be controlled via
the ice ejecting heater 25. The cooling fan may be kept on i.e.,
continuously operated, while the ice-ejecting heater 25 is
controlled to adjust the temperature of rod 23.
[0073] First, the ice making mode is initiated (operation S51),
water is supplied (operation S52), and the water supply is
completed (operation S53) similar to the first embodiment.
[0074] After the water supply is completed, the cooling fan may be
operated to supply and circulate cooling air throughout the ice
making space 11 (operation S54). The plurality of fins 24 are
cooled by convection heat transfer with the cooling air, and the
rod 23 may be cooled by conduction heat transfer with the cooled
fins 24.
[0075] The surface temperature of the rod 23 may be measured by the
rod temperature sensor 70 and may be transmitted to the control
unit 45. Then, the control unit 45 determines whether the measured
rod temperature T is equal to or greater than a first predetermined
temperature T1 (operation S55).
[0076] In detail, if it is determined that the rod temperature T is
equal to or greater than the first temperature T1, the ice ejecting
heater 25 may be turned off (operation S56). Otherwise, the ice
ejecting heater 25 is turned on (operation S57). Here, turning the
ice ejecting heater 25 on or off is similar to the above-described
"on/off" function of the cooling fan.
[0077] After the on/off operation of the ice ejecting heater 25 is
determined and a predetermined time has passed, the control unit
may determine whether ice making time (t) reaches a first set time
t1 (operation S58). If the ice making time (t) has not reach the
first set time t1, the procedure goes back to operation S55.
[0078] On the other hand, if the ice making time (t) has reached
the first set time t1, the temperature T of the rod 23 is then
reduced to a temperature lower than the first set temperature
T1.
[0079] In more detail, once the ice making time (t) reaches the
first set time t1, the current rod temperature T may be measured.
It is then determined if this measured rod temperature T is equal
to or greater than a second predetermined temperature T2 (operation
S59). Here, the second temperature T2 may be lower than the first
set temperature T1. If the rod temperature T is equal to or greater
than the second temperature T2, the ice ejecting heater 25 may be
turned off (operation S60). Conversely, if the rod temperature T is
lower than the second set temperature T2, the ice ejecting heater
25 may be turned on (operation S61).
[0080] Then, it is determined whether the ice making time (t) has
reached a second set time t2 (operation S62). This time passage
determination may be conducted while the temperature T of the rod
23 is maintained at the second set temperature T2.
[0081] As illustrated in FIG. 9, if the ice making time (t) has not
reached the second set time t2, the procedure goes back to
operation S59. Conversely, if the ice making time (t) has reached
the second set time t2, an ice ejecting operation may be performed
(S63). After the ice is ejected, the ice making mode may be turned
off (operation S64).
[0082] According to the above-described method, the ice ejecting
heater 25 may be used to control the ice-making environment to make
transparent ice. That is, if the rod temperature T is reduced to
below a temperature suitable for making transparent ice, the ice
ejecting heater 25 is turned on to heat the rod 23. Therefore, the
temperature of water filled in the tray 21 may be properly
controlled so that air contained in the water can escape as the
water freezes.
[0083] In the second exemplary embodiment, the temperature of water
filled in the tray 21 may be adjusted by controlling the ice
ejecting heater 25. However, the method of the present disclosure
is not limited to this. For example, a voltage applied to the ice
ejecting heater 25 can be controlled using a semiconductor switch
device, such as a TRIAC or a thyristor. In this case, if the
temperature T of the rod 23 is lower than a set temperature T1 or
T2, the amplitude of the voltage applied to the ice ejecting heater
25 may be increased to generate more heat. Conversely, if the
temperature T is higher than a set temperature the amplitude of the
voltage applied to the ice ejecting heater 25 may be reduced to
generate less heat. Further, the temperature T of the rod 23 may be
steadily (continuously) reduced instead of being reduced in a
stepped manner.
[0084] FIG. 10 is a flowchart depicting a method of making
transparent ice using an ice making assembly according to a third
embodiment.
[0085] As illustrated in FIG. 10, in the exemplary embodiment, the
temperature of water supplied to the tray 21 may be controlled by
cooperatively operating the ice ejecting heater 25 and the cooling
fan.
[0086] First, it is noted that turning on the ice making mode
(operation S71), water supply (operation S72), and completion of
water supply (operation S73) are performed in the same way as in
the first embodiment.
[0087] In detail, after water supply is completed, it is determined
whether the temperature T of the rod 23 is equal to or greater than
a first predetermined temperature T1 (operation S74). If the
detected rod temperature T is equal to or greater than the first
temperature T1, the cooling fan may be turned on and the ice
ejecting heater 25 may be turned off (operation S75). Thus, cooling
air may be supplied to the ice making space 11, to cool the rod 23
to the first temperature T1. Conversely, if the rod temperature T
is lower than the first temperature T1, the cooling fan may be
turned off and the ice ejecting heater 25 may be turned on to keep
the rod temperature T at approximately first temperature (operation
S76).
[0088] While the rod temperature T is maintained at approximately
the first temperature T1, as described above, the control unit 45
determines whether the time that passed since the ice making
process began, i.e., ice making time (t), has reached a first set
time t1 (operation S77). If the ice making time (t) has not reached
the first set time t1, the procedure will go back to operation
S74.
[0089] Conversely, if the ice making time (t) has reached the first
set time t1, the temperature T of the rod 23 is reduced to and kept
at a temperature lower than the first temperature T1. That is, it
is determined whether the rod temperature T is equal to or greater
than a second predetermined temperature T2 (operation S78). Here,
the second temperature T2 is less than the first temperature
T1.
[0090] In detail, if the rod temperature T is equal to or greater
than the second temperature T2, the cooling fan may be turned on
and the ice ejecting heater 25 may be turned off (operation S79).
On the other hand, if the rod temperature T is below the second
temperature T2, the cooling fan may be turned off and the ice
ejecting heater 25 may be turned on (operation S80). Once the rod
temperature T reaches the second temperature T2, the amount of time
that has passed, i.e. an ice-making time (t), is compared to a
second set time t2. Based on this comparison it is determined
whether the ice making time (t) has reached a second set time t2
(operation S81). If the ice making time (t) has not yet reached the
second set time t2, the procedure goes back to operation S78.
[0091] If the ice making time (t) has reached the second set time
t2, the ice making operation is completed and the ice is then
ejected (S82). After the ice ejecting operation is complete, the
ice making mode is turned off (operation S83). It is noted that for
the method described above the temperature T of the rod 23 may be
reduced in a stepped manner or in a continuous/gradual manner. For
example, if the temperature T of the rod 23 is equal to or greater
than a predetermined temperature T1 or T2, the temperature T of the
rod 23 can be reduced to the set temperature by increasing the
speed of the cooling fan and reducing power to the ice ejecting
heater 25. On the other hand, if the temperature T of the 23 is
below the predetermined temperature T1 or T2, the temperature T of
the rod 23 can be increased to the predetermined temperature T1 or
T2 by reducing the speed of the cooling fan and increasing power to
the ice ejecting heater 25.
[0092] FIG. 11 is a graph depicting the temperature of a rod when a
method of controlling an ice making assembly is performed according
to an embodiment.
[0093] Referring to FIG. 11, according to the controlling methods
of the first to third exemplary embodiments, the temperature of the
rod 23 may vary as shown in the graph of FIG. 11. In the
above-described embodiments, the temperature of the rod 23 may be
reduced in two steps; however, the temperature of the rod 23 may be
reduced in three or more steps.
[0094] As shown in FIG. 11, the temperature of the rod 23 varies
slightly around the first temperature T1 for the first set time t1.
That is, the average temperature of the rod 23 is kept at
approximately at the first temperature T1. After the first set time
period t1 has passed, the temperature of the rod 23 is kept at
approximately the second set temperature T2 for the second set time
period t2 until ice making is completed.
[0095] According to the above-described controlling method, water
supplied to the tray 21 may be kept at a relatively high
temperature during the early stage of an ice making operation so as
to allow air contained in the water to escape before the water
freezes. Thereafter, the temperature of the rod 23 is reduced to
increase the ice forming rate. Accordingly, the generation of
opaque ice resulting from a rapid drop in water temperature can be
minimized.
[0096] Although embodiments have been described with reference to a
number of illustrative embodiments thereof, it should be understood
that numerous other modifications and embodiments could be devised
by those skilled in the art that will fall within the spirit and
scope of the principles of this disclosure. More particularly,
various variations and modifications are possible in the component
parts and/or arrangements of the subject combination arrangement
within the scope of the disclosure, the drawings, and the appended
claims. In addition to variations and modifications in the
component parts and/or arrangements, alternative uses will also be
apparent to those skilled in the art.
* * * * *