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USOO5127236A
United States Patent [19] [11] Patent Number: 5,127,236
von Blanquet [45] Date of Patent: Jul. 7, 1992

[54] SYSTEM AND APPARATUS FOR THE 3024590 1/1982 Fed. Rep. of Germany .
3216597 11/1983 Fed. Rep. of Germany .
MANUFACTURE OF CLEAR ICE PIECES 3314056 10/1984 Fed. Rep. of Germany .
AND CONTROL SYSTEM THEREFOR 8812951 l/l989 Fed. Rep. of Germany .
[75] Inventor: Georg von Blanquet, Baden-Baden, 3835132 4/1990 Fed. Rep. of Germany .
Fed. Rep. of Germany Primary Examiner-William E. Tapolcai
[73] Assignee: Gaggenau-Werke Haus- und Attorney, Agent, or Firm-Wenderoth, Lind 8: Ponack
Lufttechnik GmbH, Gaggenau, Fed. [57] ABSTRACT
Rep. of Germany
A coolant circuit, for example of a refrigerator or
[21] Appl. No.: 678,152 freezer unit, includes a coolant source at a very low
[22] Filed: Apr. 2, 1991 temperature. A ?nger-type chilling member is thermo
conductively connected to the coolant source and is
[30] Foreign Application Priority Data adapted to be positioned within a tank containing water
Apr. 14, 1990 [DE] Fed. Rep. of Germany ..... .. 4012249 that is ?owed to wash around the member. Thereby, the
water freezes on the member in the form of a clear ice
[51] Int. Cl.5 .............................................. .. F25C 5/08
[52] US. Cl. ......................... .. 62/135; 62/351
piece. A heating device is connected to the member to
[58] Field of Search ................. .. 62/73, 351, 352, 353, selectively heat the member to detach therefrom the ice
‘ 62/ 135 piece formed thereon. A thermal barrier is connected to
the member at a position to separate the heating device
[56] References Cited and that portion of the member on which the ice piece
U.S. PATENT DOCUMENTS is formed from the coolant source. The thermal barrier
2,900,804 8/1959 Rising ............................. .. 62/352 X
thus limits cooling of the member by the coolant source
2,954,679 10/1960 Blackett .. 62/353 X and also limits transfer of heat from the heating device
3,287,927 ll/l966 Jacobus .. . . .. . . . . . . .. 62/135 to the coolant source. A control circuit includes a regu
3,380,261 4/l968 Hendrix et a1. . ..... .. 62/353 X lating circuit to operate the heating device to maintain
3,433,030 3/1969 Jacobs . . . . .. . . . . . . . . .. 62/351 X
the temperature of the member at an approximately
4,199,956 4/1980 Lunde . .. . . . . . . . . . . . . . . . .. 62/352 X
constant value above a predetermined minimum value
4,366,856 1/1983 Yanadori et a1. ............... .. 62/351 X
necessary to produce clear ice pieces.
FOREIGN PATENT DOCUMENTS
0333887 9/1989 European Pat. Off. .
37 Claims, 2 Drawing Sheets
US. Patent _ July 7, 1992 Sheet 1 0r 2 5,127,236
US. Patent July 7, 1992 Sheet 2 of 2 . 5,127,236

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 5,127,236 2
1
erated products, there is an additional section for pre
SYSTEM AND APPARATUS FOR THE paring chilled drinking water. One evaporator is allo
MANUFACTURE OF CLEAR ICE PIECES AND cated to the refrigerated products compartment and the
CONTROL SYSTEM THEREFOR other evaporator is allocated to the additional section
for storing chilled drinking water. ,
BACKGROUND OF THE INVENTION
SUMMARY OF THE INVENTION
The present invention relates to an apparatus for the
manufacture of clear ice pieces, particularly for use With the above discussion in mind, it is an object of
with a refrigerator or freezer unit including a cooling the present invention to provide an apparatus and sys
circuit having a coolant source at a very low tempera tem for the manufacture of clear ice pieces, and includ
ture, the apparatus including a ?nger-type chilling ing a cooling circuit of a refrigerator or freezer unit, or
member adapted to be positioned within a tank contain particularly for use with such a refrigerator or freezer
ing water to be caused to ?ow to wash around the unit including a cooling circuit, whereby it is possible to
member and adapted to be thermoconductively con produce perfect, clear ice pieces with only minor addi
nected to the coolant source to be cooled thereby such tional refrigerant consumption. It also is an object of the
that the water freezes on the member in the form of a present invention to provide a control system for use
clear ice piece, and a heating device operatively con with such an apparatus and system.
nected to the member to selectively heat the member to The above objects are achieved in accordance with
detach therefrom an ice piece formed thereon. The the present invention by the provision of a thermal
present invention also relates to a system for manufac barrier provided at a position to separate a ?nger-type
turing clear ice pieces, such system including a refriger chilling member and a heating device from the coolant
ator or freezer unit including a cooling circuit having an source, for example a refrigerant line. This arrangement
evaporator and a coolant source at a very low tempera provides the advantage that the ?nger-type chilling
ture, as well as one or more of the above discussed member or members are not excessively cooled by di
apparatus. Yet further, the present invention relates to a 25 rect thermal contact with the coolant source, for exam
control system for controlling the temperature of the ple the refrigerant line that contains refrigerant that
?nger-type chilling member of such an apparatus. may be at a very low temperature, for example as low as
German Registered Utility Model No. 88 12 951 and —30‘’ C. As a result, the thermal barrier makes it possi
German Patent Speci?cation No. 38 35 132 describe a ble to ensure that the surface temperature of the ?nger
device for the manufacture of clear ice pieces, wherein type chilling members does not fall below a predeter
a water flow is generated such that water moves back mined lower temperature limit. For example, it is possi
and forth within a tank, such tank being moved by a ble to ensure that the surface temperature of the ?nger
swinging drive mechanism whereby the water flow type chilling members does not fall below approxi
washes about ?nger-type chilling devices which project mately -10° C., which is a favorable temperature for
into the tank. Such chilling devices are thermoconduc 35
the manufacture of clear ice particles. Furthermore, to
tively connected to a refrigerant line of a cooling de maintain this lower temperature limit, for example by
vice, such that ice pieces freeze and are formed on the heating the ?nger-type chilling members, the provision
chilling devices. In this known device, the ice formation of the thermal barrier limits the transfer of heat from the
is achieved speci?cally from the ?nger-type chilling heating device back to the coolant source. That is, heat
devices. A tilting tank with a residual water storage 40 from the heating device is isolated from the coolant
container is disclosed in German Patent Speci?cation source, thereby avoiding lowering of the refrigerating
No. 32 16 597. Also, the detachment of the hollow ice
effect of the coolant source. '
pieces frozen tightly to such ?nger-type chilling devices As employed herein, the term “thermal barrier" is
is known to be achieved by heating the ?nger-type
chilling devices. Heating of ice pieces formed in indi5 45 intended to refer to one-piece or composite arrange
vidual compartments of a tank to detach them after ments, for example of thermal insulation material, that
reduce thermal transfer between the coolant source and
completion of the freezing process is disclosed ‘in Euro
pean Patent Speci?cation No. 0 333 887.
the section of the ?nger-type chilling members on
German Patent Speci?cation No. 33 14 056 discloses which the ice pieces are formed. In a speci?c example
a freezer unit, particularly a freezer cabinet, in which an of the present invention, the coolant source will be a
evaporation system or evaporator is subdivided into at refrigerant line fed with refrigerant at very low temper~
least two evaporation sections allocated to respective atures. However, other coolant sources may be em
thermally separated compartments of the cabinet. At ployed, for example a coolant source of solid metal that
least one of these evaporation sections can be bridged is connected to a refrigerating apparatus or unit of any
by a controllable bypass feeder, and an additional evap 55 known type.
orator is allocated to the bridged evaporation section, As employed herein the term “?nger-type chilling
the effective surface of such additional evaporator member” refers to a structure, element or member that
being substantially less than that of the bridged evapora is of or includes an elongated con?guration and having
tion section. This arrangement is intended to compen a suitable outer surface on which may freeze water to
sate for disadvantages that arise due to ?uctuating load form clear ice pieces. In accordance with a particular
status and unit capacity factor by economical adjust embodiment of the present invention, such ?nger-type
ment of the evaporation output to the load status. chilling member includes a projecting (or connecting)
Switching is effected by three-way solenoid valves. section, for example formed of thermally conductive
Switching of refrigerant ?ow between two evaporators: metal, that is thermally connected to the coolant source,
each of which is individually connected, is disclosed in 65 as well as a ?nger section on which is to be formed an
German Patent Speci?cation No. 30 24 590. Therein is ice piece, with the thermal barrier positioned between
disclosed a domestic refrigerator or freezer unit in the projecting section and the ?nger section. The ther
which, in addition to a compartment for storing refrig mal barrier is formed of material having poor thermal
 5,127,236 4
3
conductive properties. This thermal barrier thus re cuit, connected to the temperature sensor and to the
duces thermal transfer from the coolant source to the heating device, particularly an electrical heating device,
freezing section, i.e. the ?nger section, of the member, for controlling the operation of the heating device as a
on the one hand, and, on the other hand, undesirable function of the temperature of the ?nger section de
heat feedback to the coolant source is substantially tected by the temperature sensor. Particularly, the con
restricted when the ?nger section is heated by the heat trol circuit includes means for operating the heating
ing device to remove a frozen ice piece from the ?nger device to maintain the temperature of the ?nger section
section, or for other purposes. Both the projecting sec at an approximately constant temperature value above a
tion and the ?nger section may be formed of suitable predetermined minimum temperature value necessary
thermally conductive materials, for example metal ma to produce clear ice pieces. For example, such predeter
terials. The projecting and ?nger sections may be cou mined minimum temperature value may be -10° C.
pled together by a connection (or coupling) member, This may be achieved in the form of a regulating circuit
for example a screw connection formed of material controlling operation of the electrical heating device to
having poor thermoconductive properties. Such screw maintain the temperature of the ?nger section of the
connection may be in the form of a grub screw, for chilling member, i.e. the portion of the chilling member
example. Also, the thermal barrier may include a wash isolated from the coolant source by the thermal barrier,
er-shaped member extending outwardly from between above the predetermined minimum temperature. In
the projecting and ?nger sections of the member. Such other words, it is possible to ensure that the temperature
insulating washer may be formed of various materials of the ?nger section does not drop below the predeter
having poor thermally conductive properties, for exam 20 mined minimum value that would degrade the quality
ple thermal insulating material. Examples may be metal and clarity of ice pieces formed. The regulating circuit
materials, particularly special steels, or various plastic includes the electrical temperature sensor that is ther
materials. .
mally connected to the ?nger section, and advanta
In accordance with a'further feature of this embodi geously would operate employing a clock system by
ment of the invention, the insulating washer may be 25 switching the electrical heating device on and off. This
designed as an attachment or support element for the type of regulating circuit for maintaining a constant
heating device that is employed to selectively heat the temperature, as a function of signals from a temperature
?nger section of the chilling member. Thus, the heating sensor, for example an NTC/PTC, is well known in
device may be retained in a support member that is various environments. Thus, one skilled in the art
connected to the washer member. Particularly, the sup readily would understand what type of known elements
port member may have retaining or locating portions could be employed for the regulating circuit of the
that engage in recesses or openings in the washer mem present invention.
ber. The support member particularly may be pot As a result of the above features of the present inven
shaped and/or may be formed of thermally insulating tion, it is possible to ensure the accurate manufacture of
material. The heating device, for example an electrical 35 perfect clear ice pieces, particularly on a domestic scale,
heating coil, can be retained within the support member with optimum utilization of the cooling output already
and thus supported by the washer member. available, for example a compressor cooling unit, and
In accordance with a further feature of the present without the danger of excessively low temperatures
invention the coolant source in the form of a refrigerant being imparted to the ?nger-type chilling members that
line optionally can be connected in series to an evapora 40 otherwise would cause micro-cracking and therefore
tor of the cooling circuit of the refrigerator or freezer clouding of the ice pieces.
unit, particularly a domestic refrigerator, during the BRIEF DESCRIPTION OF THE DRAWINGS
operation of manufacture or production of clear ice
pieces. This selective connector arrangement dispenses Other objects, features and advantages will be appar
with the need for additional compressor cooling strucl 45 ent from the following detailed description, taken with
ture and simply makes additional use of the existing the accompanying drawings, wherein:
compressor of the cooling circuit during production of FIG. 1 is a partial cross sectional view illustrating a
clear ice pieces. In such an arrangement it is advisable to ?nger-type chilling member employed in an apparatus
provide a three-way valve, particularly in the form of a according to an embodiment of the present invention;
solenoid valve, for optional or selective connection of 50 FIG. 2 is a sectional view along line 11-11 in FIG. 1;
the refrigerant line into the refrigeration or cooling FIG. 3 is a diagram of a system according to the
circuit of the refrigerator unit. This arrangement pro invention and including a cooling circuit of a domestic
vides advantageous additional use of the existing refrig refrigerator coupled with an apparatus for the manufac
erant or cooling circuit during the manufacture of ice. ture of clear ice pieces according to the present inven
The cooling circuit of the domestic refrigerator, which 55 tion; and
may have a freezer section, is subjected to an additional FIG. 4 is a view similar to FIG. 1 but also schemati
load only during manufacture of ice pieces, simply by cally illustrating a circuit diagram of a control system
switching the refrigerant line that forms the coolant according to the present invention.
source for the apparatus of the invention into the cool DETAILED DESCRIPTION OF THE
ing circuit when needed. It is useful if the refrigerant INVENTION
line can be connected in series to the evaporator of the
cooling circuit of the refrigerator or freezer unit in the In FIGS. 1 and 2 is shown a ?nger-type chilling mem
direction of ?ow of the refrigerant ,therethrough. I ber 1 formed of a metal, thermally conductive project
In accordance with a further feature of the present ing (or connecting) section 2 and a metal, thermally
invention, there is provided a temperature sensor, for 65 conductive ?nger section 3. Projecting section 2 is ther
example an electrical temperature sensor, for detecting moconductively connected, for example by means of a
the temperature of the ?nger section of the chilling metallic bond, to a coolant source, for example a refrig
member. Furthermore, there is provided a control cir erant line 6 containing refrigerant at a very low temper
 5,127,236 ‘
5 6
ature, and to be discussed in more detail below. Sections clear ice pieces 17 on ?nger sections 3 have reached a
2 and 3 are connected together but are separated by a suitable thickness, for example ascertained by a mechan
thermal barrier. Particularly, sections 2, 3 are connected ical or other scanning sensor element, electrical heating _
by a connection (or coupling) member 4, for example a coils 14 are switched on by control circuit 24 until the
grub screw, formed of a material, for example a special clear ice pieces 17 are detached from ?nger sections 3 as
steel, having poor thermoconductive properties. Addi a result of sufficient heating of sections 3 by heating
tionally, an insulating washer-shaped member 5, also coils 14. The clear ice pieces thus drop into a collection
formed of a material such as a special steel having poor tank for further storage or processing. Furthermore,
thermoconductive properties extends outwardly from control circuit 24 may include a regulating circuit to
the joint between sections 2, 3. As a result, sections 2, 3 operate electrical heating coils 14 to maintain the tem
are separated by thermal barrier 4, 5. perature of ?nger sections 3 at an approximately con
Finger section 3 is positioned within a tank 16 con stant temperature value above a predetermined mini
taining water to be ?owed to wash around section 3 and , mum temperature value, for example —l0° C., neces
cooled thereby such that the water freezes on section 3 sary to produce clear ice pieces. That is, signals from
in the form of a clear ice piece 17. A heating device, for temperature sensor 15 will cause the regulating circuit
example an electrical heating coil 14, is operatively of control circuit 24 to operate heating coil 14 when the
connected to section 3 so that section 3 may be selec temperature of ?nger section 3 drops below the prede
tively heated to detach therefrom ice piece 17 after termined minimum temperature value. This ensures that
formation thereof. Tank 16 and other features of the the temperature of ?nger section 3 will not drop to an
ice-forming system may be in accordance with the 20 extent such that the ice pieces formed will be cracked,
above German Registered Utility Model No. 88 12 951. cloudy or otherwise degraded.
In the illustrated arrangement, heating coil 14 is sup The provision of the thermal barrier 4, 5 facilitates
ported by washer 5. Particularly, a pot-shaped support maintaining the temperature of ?nger section 3 at the
member 13 formed of a thermally insulating material, predetermined minimum temperature value. That is,
for example plastic, has three symmetrically arranged 25 thermal barrier 4, 5 limits the cooling of finger section 3
locating portions or catches 10, 11, 12 that ?t into and by coolant source 6. Additionally, thermal barrier 4, 5
engage in respective recesses or openings 7, 8, 9 of limits heat being transferred to coolant source 6 upon
insulating washer 5. Electrical heating coil 14 is accom operation of heating coil 14.
modated within support member 13. The apparatus for the production of clear ice pieces
There additionally is provided a temperature sensor 30 according to the present invention can be manufactured
15, for example an electrical temperature sensor, for either as a separate unit or, particularly-usefully in con
detecting the temperature of ?nger section 3. A plural nection with refrigerator or freezer units, particularly
ity of the units shown in FIGS. 1 and 2 may be posi domestic models, for example as a built-in component of
tioned within tank 16 to form a plurality of clear ice
35 a domestic refrigerator.
pieces 17. Although the present invention has been described
FIG. 3 illustrates a system according to the present and illustrated with respect to preferred features
invention and including a refrigerant or cooling circuit thereof, it is to be understood that various changes and
of a domestic refrigerator. The circuit includes a com
modi?cations may be made to the speci?cally described
pressor 19, a condensor 26, a line 18, 22, a main evapora
40 and illustrated features without departing from the
tor 21, and a return line 23. As shown in FIG. 3, the
coolant source in the form of refrigerating line 6 ther scope of the present invention.
mally connected to a plurality of members 1 for forming 1 claim:
1. An apparatus for the manufacture of clear ice
clear ice pieces may be connected to such cooling cir- ‘
cuit. Particularly, a three-way solenoid valve 20 is con pieces, particularly for use with a refrigerator or freezer
nected to line 18 whereby it is possible to selectively 45 unit including a cooling circuit having a coolant source
connect line 18 through valve 20 to refrigerant line 6. at a very los temperature, said apparatus comprising:
Particularly, refrigerant flows from line 18 ‘through a ?nger-type chilling member adapted to be posi
valve 20 and a throttle 28 through coolant line 6 in tioned within a tank containing water to be ?owed
series with main evaporator 21. This connection is em to wash around said member and adapted to be
ployed when production of clear ice pieces is to occur. 50 thermoconductively connected to be coolant
When ice pieces are not being produced, valve 20 con source to be cooled thereby such that the water
nects line 18 with line 22 such that the refrigerant ?ow freezes on said member in the form of a clear ice
is from line 18 through valve 20 and a throttle 27 di piece, said ?nger-type chilling member comprising
rectly to main evaporator 21. When refrigerant line 6 is a thermally conductive connecting section adapted
connected into the cooling circuit, such connection to be connected to the coolant source, and a ther
should be in series with main evaporator 21, which may mally conductive ?nger section on which the clear
if appropriate be formed of plural parts, for example for ice piece is to be formed;
freezer and normal cooling compartments or sections of a heating device operatively connected to said ?nger
the domestic refrigerator. section to selectively heat said ?nger section to
FIG. 4 illustrates a further aspect of the present in 60 detach therefrom an ice piece formed thereon; and
vention. Particularly, a control circuit 24 is electrically thermal barrier means, connected between and sepa
connected to heater device 14 and to temperature sen rating said connecting section and said ?nger sec
sor 15. Control circuit 24 thereby controls the operation tion of said ?nger-type chilling member, for limit
of heating device 14 as a function of signals received ing cooling of said ?nger section of said ?nger-type
from temperature sensor 15 relating to the temperature 65 chilling member by the coolant source and for
of ?nger section 3. As a result, a simple, two-step con limiting back transfer of heat from said heating
trol system is provided, with power supply to control device to the coolant source when said heating
‘circuit 24 being achieved via terminals 25. Once the device is operated.
 5,127,236 8
7
2. An apparatus as claimed in claim 1, wherein said ?nger-type chilling member to selectively heat said
?nger section is formed of thermally conductive metal. ?nger section of said at least one ?nger-type chill
3. An apparatus as claimed in claim 1, wherein said ing member, respectively, to detach therefrom an
projecting section is formed of thermally conductive ice piece formed thereon; and
metal. 5. at least one thermal barrier means, respectively con
4. An apparatus as claimed in claim 1, wherein said nected between and separating said connecting
thermal barrier means is formed of material having poor section and said ?nger section of said at least one
thermal conductive properties. ?nger-type chilling member for respectively limit
5. An apparatus as claimed in claim 4, wherein said ing cooling of said ?nger section of said at least one
thermal barrier means comprises a coupling member 10 ?nger-type chilling member by said coolant source
coupling said connecting section to said ?nger section and for respectively limiting back transfer of heat
and a thermally insulating washer member between said from said at least one heating device to said coolant
connecting section and said ?nger section and sur source when said at least one heating device is
rounding said ?nger section. operated.
6. An apparatus as claimed in claim 5, wherein said 17. A system as claimed in claim 16, wherein said
heating device is supported by said washer member. ?nger section of said at least one ?nger-type chilling
7. An apparatus as claimed in claim 6, further com member is formed of thermally conductive metal.
prising a support member retaining said heating device 18. A system as claimed in claim 16, wherein said
and connected to said washer member. connecting section of said at least one ?nger-type chill
8. A system as claimed in claim 6, wherein 20 ing member is formed of thermally conductive metal.
said heating device comprises an electrical heating 19. A system as claimed in claim 16, wherein said at
coil surrounding said ?nger section of said ?nger least one thermal barrier means is formed of material
type chilling member. having poor thermal conductive properties.
9. An apparatus as claimed in claim 7, wherein said 20. A system as claimed in claim 19, wherein said at
support member has locating portions engaged in reces least one thermal barrier means comprises a coupling
ses in said washer member. member respectively coupling said connecting section
10. An apparatus as claimed in claim 7, wherein said to said ?nger section of said at least one ?nger-type
support member is pot-shaped and is formed of ther chilling member, and a thermally insulating washer
mally insulating material. member between said connecting section and said ?nger
11. An apparatus as claimed in claim 1, further com section and surrounding said ?nger section.
prising a temperature sensor for detecting the tempera 21. A system as claimed in claim 20, wherein said at
ture of said ?nger section. least one heating device is respectively supported by
12. An apparatus as claimed in claim 11, further com said washer member of said at least one thermal barrier
prising control means, connected to said temperature means. i
sensor and to said heating device, for controlling the 35 22. A system as claimed in claim 21, further compris
operation of said heating device as a function of the ing at least one support member respectively retaining
temperature of said ?nger section detected by said tem said at least one heating device and connected to said
perature sensor. washer member to said at least one thermal barrier
13. An apparatus as claimed in claim 12, wherein said
means.
control means comprises means for operating said heat 23. A system as claimed in claim 21, wherein
ing device to maintain the temperature of said ?nger said at least one heating device respectively com
section at an approximately constant value above a prises at least one electrical heating coil surround
predetermined minimum value necessary to produce ing said ?nger section of said at least one ?nger
clear ice pieces. type chilling member.
14. An apparatus as claimed in claim 1, wherein said 45 24. A system as claimed in claim 23, wherein said at
heating device comprises an electrical heating device. least one support member has locating portions engaged
15. An apparatus as claimed in claim 14, wherein said
in recesses in said washer member of said at least one
heating device comprises an electrical heating coil sur
rounding said ?nger section of said ?nger-type chilling thermal barriers means, respectively.
25. A system as claimed in claim 23, wherein said at
member. least one support member is pot-shaped and is formed of
16. A system for manufacturing clear ice pieces, said
system comprising: thermally insulating material.
a cooling 'circuit of a refrigerator or freezer unit and 26. A system as claimed in claim 16, further compris
including an evaporator and a coolant source at a ing a temperature sensor for detecting the temperature
55 of said ?nger section of said at least one ?nger-type
very low temperature;
at least one ?nger-type chilling member thermocon chilling member.
ductively connected to said coolant source to be 27. A system as claimed in claim 26, further compris
cooled thereby and adapted to be positioned within ing control means, connected to said temperature sensor
a tank containing water to be flowed to wash and to said at least one heating device, for controlling
around said at least one member, such that water the operation of said at least one heating device as a
freezes on said at least one member in the form of function of the temperature of said ?nger section of said
a clear ice piece, said at least one ?nger-type chill at least one ?nger-type chilling member detected by
ing member comprising a thermally conductive said temperature sensor.
connecting section adapted to be connected to said 28. A system as claimed in claim 27, wherein said
coolant source, and a thermally conductive ?nger 65 control means comprises means for operating said at
section on which the clear ice piece is to be formed; least one heating device to maintain the temperature of
at least on heating device respectively operatively said ?nger section of said at least one ?nger-type chill
connected to said ?nger section of said at least ‘one ing member at an approximately constant value above a
 5,127,236 10
9 member thermoconductivity connected to a coolant
predetermined minimum value necessary to produce
source of a cooling circuit of a refrigerant or freezer
clear ice pieces. unit and to be positioned within a tank containing water
29. A system as claimed in claim 16, wherein said at
least one heating device respectively comprises at least to be ?owed to wash around the member such that
water freezes on the member in the form of a clear ice
one electrical heating device.
30. A system as claimed in claim 29, wherein said at piece, said control system comprising:
least one heating device respectively comprises at least a heating device adapted to be operatively connected
one electrical heating coil surrounding said ?nger sec to a portion of the member that is partially ther
tion of said at least one ?nger-type chilling member. mally isolated from the coolant source;
a temperature sensor for detecting the temperature of
31. A system as claimed in claim 16, wherein said
coolant source comprises a refrigerant line. such member portion; and
32. A system as claimed in claim 31, further compris control means, connected to said temperature sensor
ing means for selectively connecting said refrigerant and to said heating device, for operating said heat
ing device to maintain the temperature of the mem
line in series with said evaporator in order to manufac
15 ber portion at an approximately constant value
ture the clear ice piece. above a predetermined minimum value necessary
33. A system as claimed in claim 32, wherein said
connecting means comprises a three-way valve pro to produce the clear ice pieces.
36. A control system as claimed in claim 35, wherein
vided in said cooling circuit. said heating device comprises an electrical heating de
34. A system as claimed in claim 32, wherein said
series connection is in the direction of refrigerant flow 20 vice.
37. A control system as claimed in claim 36, wherein
through said cooling circuit. said heating device comprises an electrical heating coil
35. A control system for controlling the temperature
of an apparatus to be employed for the manufacture of adapted to surround the member portion.
* t t is t
clear ice pieces and to' include a ?nger-type chilling
25

35

50

55

65