U.S. patent application number 11/543484 was filed with the patent office on 2007-05-10 for thermally conductive ice-forming surfaces incorporating short-duration electro-thermal deicing.
This patent application is currently assigned to MILE HIGH EQUIPMENT LLC. Invention is credited to John Allen Broadbent.
Application Number | 20070101753 11/543484 |
Document ID | / |
Family ID | 38035958 |
Filed Date | 2007-05-10 |
United States Patent
Application |
20070101753 |
Kind Code |
A1 |
Broadbent; John Allen |
May 10, 2007 |
Thermally conductive ice-forming surfaces incorporating
short-duration electro-thermal deicing
Abstract
An ice making machine comprising: a thermally conductive plastic
or aluminum evaporator assembly comprising an array of ice forming
surfaces; a water supply, a refrigerant supply and an electrical
energy source; and a controller that during a freeze mode operates
the water supply and the refrigerant supply to form ice on the ice
forming surfaces and during a harvest mode operates the electrical
energy source to apply electrical resistance energy (e.g., pulsed
energy) to the evaporator assembly to melt an interfacial layer of
the ice such that it is freed from the surfaces. Alternatively, the
thermally conductive plastic or aluminum evaporator can include
freezing tubes with resistance energy deicing (e.g., pulsed energy)
or shell and tube type evaporators with pulsed energy deicing.
Inventors: |
Broadbent; John Allen;
(Denver, CO) |
Correspondence
Address: |
Paul D. Greeley;Ohlandt, Greeley, Ruggiero & Perle, L.L.P.
10th Floor
One Landmark Square
Stamford
CT
06901-2682
US
|
Assignee: |
MILE HIGH EQUIPMENT LLC
|
Family ID: |
38035958 |
Appl. No.: |
11/543484 |
Filed: |
October 5, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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60724223 |
Oct 6, 2005 |
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60724243 |
Oct 6, 2005 |
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60724254 |
Oct 6, 2005 |
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Current U.S.
Class: |
62/349 ; 62/137;
62/351 |
Current CPC
Class: |
F25B 39/02 20130101;
F25C 1/145 20130101; F25C 5/08 20130101 |
Class at
Publication: |
062/349 ;
062/137; 062/351 |
International
Class: |
F25C 1/00 20060101
F25C001/00; F25C 5/08 20060101 F25C005/08 |
Claims
1. An ice making machine comprising: a thermally conductive plastic
evaporator assembly comprising an array of ice forming surfaces; a
water supply, a refrigerant supply and an electrical energy source;
and a controller that during a freeze mode operates said water
supply and said refrigerant supply to form ice on said ice forming
surfaces and during a harvest mode operates said electrical energy
source to apply electrical resistance energy to said evaporator
assembly to melt an interfacial layer of said ice such that it is
freed from said surfaces.
2. The ice making machine of claim 1, wherein said evaporator
assembly comprises a thermally conductive plastic base portion and
a heater, wherein said heater is affixed to a surface of said
thermally conductive plastic base portion, such that said heater is
disposed between said ice and said base portion.
3. The ice making machine of claim 2, wherein said heater comprises
a flexible membrane and an electrical trace disposed on said
flexible membrane.
4. The ice making machine of claim 2, wherein said thermally
conductive plastic base portion and said heater form an ice cell
which is capable of forming ice shapes.
5. The ice making machine of claim 2, wherein said heater is
affixed to said thermally conductive plastic base portion by at
least one selected from the group consisting of: adhesive, solvent
bonding, ultrasonic bonding, and heat fusing.
6. The ice making machine of claim 1, wherein said electrical
resistance energy is electrical pulse energy.
7. A method of making ice with an ice making machine that comprises
a thermally conductive plastic evaporator assembly comprising an
array of ice forming surfaces, a water supply, a refrigerant supply
and an electrical energy source, said method comprising: during a
freeze mode operating said water supply and said refrigerant supply
to form ice on said ice forming surfaces; and during a harvest mode
operating said electrical energy source to apply electrical
resistance energy to said evaporator assembly to melt an
interfacial layer of said ice such that it is freed from said
surfaces.
8. The method of claim 7, wherein said evaporator assembly
comprises a thermally conductive plastic base portion and a heater,
wherein said heater is affixed to a surface of said thermally
conductive plastic base portion, such that said heater is disposed
between said ice and said base portion.
9. The method of claim 8, wherein said heater comprises a flexible
membrane and an electrical trace disposed on said flexible
membrane.
10. The method of claim 8, wherein said thermally conductive
plastic base portion and said heater form an ice cell which is
capable of forming ice shapes.
11. The method of claim 8, wherein said heater is affixed to said
thermally conductive plastic base portion by at least one selected
from the group consisting of: adhesive, solvent bonding, ultrasonic
bonding, and heat fusing.
12. The method of claim 7, wherein said electrical resistance
energy is electrical pulse energy.
13. An evaporator assembly for forming ice, said assembly
comprising: a thermally conductive plastic base portion and an
electrical resistance heater, wherein said heater is affixed to a
surface of said thermally conductive plastic base portion, such
that said heater is disposed between said ice and said base
portion.
14. The evaporator assembly according to claim 13, wherein said
heater comprises a flexible membrane and an electrical trace
disposed on said flexible membrane.
15. The evaporator assembly according to claim 14, wherein said
thermally conductive plastic base portion and said heater form an
ice cell which is capable of forming ice shapes.
16. The evaporator assembly according to claim 13, wherein said
heater is affixed to said thermally conductive plastic base portion
by at least one selected from the group consisting of: adhesive,
solvent bonding, ultrasonic bonding, and heat fusing.
17. The evaporator assembly according to claim 13, wherein said
electrical resistance heater is an electrical pulse heater.
18. An ice making machine comprising: an evaporator assembly
comprising at least one freezing tube and at least two thermally
conductive plastic or metal evaporator plates, wherein said
freezing tube is disposed between oppositely disposed evaporator
plates; at least one refrigerant conduit disposed within said
thermally conductive plastic or metal evaporator plates; a water
supply in communication with an inlet port of said freezing tube; a
refrigerant supply in communication with said refrigerant conduit;
an electrical energy source in communication with said freezing
tube; and a controller that during a freeze mode operates said
water supply and said refrigerant supply to form ice on an interior
surface of said freezing tube and during a harvest mode operates
said electrical energy source to apply electrical resistance energy
to said freezing tube or to a heater disposed about said freezing
tube to melt an interfacial layer of said ice formed on said
interior surface of said freezing tube such that it is freed from
said interior surface.
19. The ice making machine according to claim 18, wherein said
evaporator plate comprises at least first and second thermal
transfer nodes which are spaced apart from one another and in
thermal contact with an outer surface said freezing tube, thereby
forming ice on said interior surface of said freezing tube at a
location defined by contacting of said thermal transfer nodes and
said freezing tube.
20. The ice making machine according to claim 18, further
comprising an electrical insulation layer disposed about the
exterior surface of said freezing tube, such that ice is not formed
on said interior surface of said freezing tube at a location where
said thermal transfer nodes are not in direct contact with said
freezing tube.
21. The ice making machine according to claim 18, wherein said
electrical resistance energy is electrical pulse energy.
22. A method of making ice with an ice making machine that
comprises an evaporator assembly comprising at least one freezing
tube and at least two thermally conductive plastic or metal
evaporator plates, wherein said freezing tube is disposed between
oppositely disposed evaporator plates, a water supply, a
refrigerant supply and an electrical energy source, said method
comprising: during a freeze mode operating said water supply and
said refrigerant supply to form ice on an interior surface of said
freezing tube; and during a harvest mode operating said electrical
energy source to apply electrical resistance energy to said
freezing tube to melt an interfacial layer of said ice such that it
is freed from said interior surface of said freezing tube.
23. The method according to claim 22, wherein said evaporator plate
comprises at least first and second thermal transfer nodes which
are spaced apart from one another and in thermal contact with an
outer surface said freezing tube, thereby forming ice on said
interior surface of said freezing tube at a location defined by
contacting of said thermal transfer nodes and said freezing
tube.
24. The method according to claim 22, further comprising an
electrical insulation layer disposed about the exterior surface of
said freezing tube, such that ice is not formed on said interior
surface of said freezing tube at a location where said thermal
transfer nodes are not in direct contact with said freezing
tube.
25. The method according to claim 22, wherein said electrical
resistance energy is electrical pulse energy.
26. An evaporator assembly for forming ice, said assembly
comprising: at least one freezing tube; at least two thermally
conductive plastic or metal evaporator plates, wherein said
freezing tube is disposed between oppositely disposed evaporator
plates; a refrigerant conduit disposed substantially within said
evaporator plate; and an energy source connected to or disposed
about said freezing tube for applying electrical resistance energy
to said freezing tube or to a heater disposed about said freezing
tube, thereby melting an interfacial layer of said ice formed on
said interior surface of said freezing tube such that it is freed
from said interior surface.
27. The evaporator assembly according to claim 26, wherein said
heater comprises a flexible membrane and an electrical trace
disposed on said flexible membrane.
28. The evaporator assembly according to claim 26, wherein said
electrical resistance energy is electrical pulse energy.
29. An ice making machine comprising: an evaporator assembly
comprising at least one freezing tube and at least two thermally
conductive plastic or metal evaporator segments, wherein said
freezing tube is disposed between oppositely disposed evaporator
segments; at least one refrigerant conduit disposed substantially
perpendicularly through said thermally conductive plastic or metal
evaporator segments; a water supply in communication with an inlet
port of said freezing tube; a refrigerant supply in communication
with said refrigerant conduit; an electrical energy source in
communication with said freezing tube; and a controller that during
a freeze mode operates said water supply and said refrigerant
supply to form ice on an interior surface of said freezing tube and
during a harvest mode operates said electrical energy source to
apply electrical resistance energy to said freezing tube or to a
heater disposed about said freezing tube to melt an interfacial
layer of said ice formed on said interior surface of said freezing
tube such that it is freed from said interior surface.
30. The ice making machine according to claim 29, wherein said
evaporator segment comprises at least first and second thermal
transfer nodes which are spaced apart from one another and in
thermal contact with an outer surface said freezing tube, thereby
forming ice on said interior surface of said freezing tube at a
location defined by contacting of said thermal transfer nodes and
said freezing tube.
31. The ice making machine according to claim 29, further
comprising an electrical insulation layer disposed about the
exterior surface of said freezing tube, such that ice is not formed
on said interior surface of said freezing tube at a location where
said thermal transfer nodes are not in direct contact with said
freezing tube.
32. The ice making machine according to claim 29, wherein said
electrical resistance energy is electrical pulse energy.
33. A method of making ice with an ice making machine that
comprises an evaporator assembly comprising at least one freezing
tube and at least two thermally conductive plastic or metal
evaporator segments, wherein said freezing tube is disposed between
oppositely disposed evaporator segments, a water supply, a
refrigerant supply and an electrical energy source, said method
comprising: during a freeze mode operating said water supply and
said refrigerant supply to form ice on an interior surface of said
freezing tube; and during a harvest mode operating said electrical
energy source to apply electrical resistance energy to said
freezing tube to melt an interfacial layer of said ice such that it
is freed from said interior surface of said freezing tube.
34. The method according to claim 33, wherein said evaporator plate
comprises at least first and second thermal transfer nodes which
are spaced apart from one another and in thermal contact with an
outer surface said freezing tube, thereby forming ice on said
interior surface of said freezing tube at a location defined by
contacting of said thermal transfer nodes and said freezing
tube.
35. The method according to claim 33, further comprising an
electrical insulation layer disposed about the exterior surface of
said freezing tube, such that ice is not formed on said interior
surface of said freezing tube at a location where said thermal
transfer nodes are not in direct contact with said freezing
tube.
36. The method according to claim 33, wherein said electrical
resistance energy is electrical pulse energy.
37. An evaporator assembly for forming ice, said assembly
comprising: at least one freezing tube; at least two thermally
conductive plastic or metal evaporator segments, wherein said
freezing tube is disposed between oppositely disposed evaporator
segments; a refrigerant conduit disposed substantially
perpendicular to said evaporator segments; and an energy source
connected to or disposed about said freezing tube for applying
electrical resistance energy to said freezing tube or to a heater
disposed about said freezing tube, thereby melting an interfacial
layer of said ice formed on said interior surface of said freezing
tube such that it is freed from said interior surface.
38. The evaporator assembly according to claim 37, wherein said
heater comprises a flexible membrane and an electrical trace
disposed on said flexible membrane.
39. The evaporator assembly according to claim 37, wherein said
electrical resistance energy is electrical pulse energy.
40. An ice making machine comprising: an evaporator assembly
comprising a freezing tube, a shell disposed about said freezing
tube, a plurality of insulating rings disposed at spaced apart
longitudinal locations about the length of said freezing tubes, and
refrigerant inlet and outlet ports disposed within a sidewall of
said shell; a water supply in communication with an inlet port of
said freezing tube; a refrigerant supply in communication with said
refrigerant inlet port; an electrical energy source in
communication with said freezing tube; and a controller that during
a freeze mode operates said water supply and said refrigerant
supply to form ice on an interior surface of said freezing tube and
during a harvest mode operates said electrical energy source to
apply electrical resistance energy to said freezing tube to melt an
interfacial layer of said ice formed on said interior surface of
said freezing tube such that it is freed from said interior
surface.
41. The ice making machine according to claim 40, wherein said
electrical resistance energy is electrical pulse energy.
42. A method of making ice with an ice making machine that
comprises an evaporator assembly comprising a freezing tube, a
shell disposed about said freezing tube, a plurality of insulating
rings disposed at spaced apart longitudinal locations about the
length of said freezing tube, and refrigerant inlet and outlet
ports disposed within a sidewall of said shell, a water supply, a
refrigerant supply connected to said refrigerant inlet port, and an
electrical energy source, said method comprising: during a freeze
mode operating said water supply and said refrigerant supply to
form ice on an interior surface of said freezing tube; and during a
harvest mode operating said electrical energy source to apply
electrical resistance energy to said freezing tube to melt an
interfacial layer of said ice such that it is freed from said
interior surface of said freezing tube.
43. The method according to claim 42, wherein said electrical
resistance energy is electrical pulse energy.
44. An evaporator assembly for forming ice, said assembly
comprising: a freezing tube; a shell disposed about said freezing
tube; a plurality of insulating rings disposed at spaced apart
longitudinal locations about the length of said freezing tube; and
refrigerant inlet and outlet ports disposed within a sidewall of
said shell; and an energy source connected to or disposed about
said freezing tube for applying electrical resistance energy to
said freezing tube, thereby melting an interfacial layer of said
ice formed on said interior surface of said freezing tube such that
it is freed from said interior surface.
45. The evaporator assembly according to claim 44, wherein said
electrical resistance energy is electrical pulse energy.
46. An ice making machine comprising: an evaporator assembly
comprising a plurality of freezing tubes, a shell disposed about
said freezing tubes, a plurality of insulating rings disposed at
spaced apart longitudinal locations about the length of each said
freezing tubes, and refrigerant inlet and outlet ports disposed
within a sidewall of said shell; a water supply in communication
with an inlet port of each said freezing tube; a refrigerant supply
in communication with said refrigerant inlet port; an electrical
energy source in communication with each of said freezing tubes;
and a controller that during a freeze mode operates said water
supply and said refrigerant supply to form ice on an interior
surface of said freezing tubes and during a harvest mode operates
said electrical energy source to apply electrical resistance energy
to said freezing tubes to melt an interfacial layer of said ice
formed on said interior surface of said freezing tube such that it
is freed from said interior surface.
47. The ice making machine according to claim 46, wherein said
electrical resistance energy is electrical pulse energy.
48. A method of making ice with an ice making machine that
comprises an evaporator assembly comprising a plurality of freezing
tubes, a shell disposed about said freezing tubes, a plurality of
insulating rings disposed at spaced apart longitudinal locations
about the length of each said freezing tubes, and refrigerant inlet
and outlet ports disposed within a sidewall of said shell, a water
supply, a refrigerant supply connected to said refrigerant inlet
port, and an electrical energy source, said method comprising:
during a freeze mode operating said water supply and said
refrigerant supply to form ice on an interior surface of said
freezing tubes; and during a harvest mode operating said electrical
energy source to apply electrical resistance energy to said
freezing tubes to melt an interfacial layer of said ice such that
it is freed from said interior surface of said freezing tubes.
49. The method according to claim 48, wherein said electrical
resistance energy is electrical pulse energy.
50. An evaporator assembly for forming ice, said assembly
comprising: a plurality of freezing tubes; a shell disposed about
said freezing tubes; a plurality of insulating rings disposed at
spaced apart longitudinal locations about the length of each said
freezing tubes; and refrigerant inlet and outlet ports disposed
within a sidewall of said shell; and an energy source connected to
or disposed about said freezing tubes for applying electrical
resistance energy to said freezing tubes, thereby melting an
interfacial layer of said ice formed on said interior surface of
said freezing tubes such that it is freed from said interior
surface.
51. The evaporator assembly according to claim 50, wherein said
electrical resistance energy is electrical pulse energy.
52. An ice making machine comprising: an evaporator assembly
comprising a helical tube, said helical tube comprising a freezing
tube and at least one refrigerant conduit disposed about said
freezing tube; a water supply in communication with an inlet port
of said freezing tube; a refrigerant supply in communication with
refrigerant conduit; an electrical energy source in communication
with said freezing tube; and a controller that during a freeze mode
operates said water supply and said refrigerant supply to form ice
on an interior surface of said freezing tube and during a harvest
mode operates said electrical energy source to apply electrical
resistance energy to said freezing tube to melt an interfacial
layer of said ice formed on said interior surface of said freezing
tube such that it is freed from said interior surface.
53. The ice making machine according to claim 52, wherein said
electrical resistance energy is electrical pulse energy.
54. A method of making ice with an ice making machine that
comprises an evaporator assembly comprising a helical tube, said
helical tube comprising a freezing tube and at least one
refrigerant conduit disposed about said freezing tube, a water
supply, a refrigerant supply connected to said refrigerant conduit,
and an electrical energy source, said method comprising: during a
freeze mode operating said water supply and said refrigerant supply
to form ice on an interior surface of said freezing tube; and
during a harvest mode operating said electrical energy source to
apply electrical resistance energy to said freezing tube to melt an
interfacial layer of said ice such that it is freed from said
interior surface of said freezing tube.
55. The method according to claim 54, wherein said electrical
resistance energy is electrical pulse energy.
56. An evaporator assembly for forming ice, said assembly
comprising: a helical tube, said helical tube comprising a freezing
tube and at least one refrigerant conduit disposed about said
freezing tube; and an energy source connected to or disposed about
said freezing tube for applying electrical resistance energy to
said freezing tube, thereby melting an interfacial layer of said
ice formed on said interior surface of said freezing tube such that
it is freed from said interior surface.
57. The evaporator assembly according to claim 56, wherein said
electrical resistance energy is electrical pulse energy.
Description
RELATED APPLICATION
[0001] This application claims the benefit of U.S. Provisional
Patent Application, Ser. No. 60/724,223, filed Oct. 6, 2005, the
entire contents of which are hereby incorporated by reference, U.S.
Provisional Patent Application, Ser. No. 60/724,243, filed Oct. 6,
2005, the entire contents of which are hereby incorporated by
reference, and U.S. Provisional Patent Application, Ser. No.
60/724,254, filed Oct. 6, 2005, the entire contents of which are
hereby incorporated by reference.
FIELD OF THE INVENTION
[0002] The present disclosure relates to an ice making machine and,
more particularly, to various ice making machines comprising a
thermally conductive plastic or aluminum evaporator that harvests
ice with electrical energy, e.g., PETD. The evaporator can be of a
variety of types, such as, cube, shell and tube, freezing tube,
etc.
BACKGROUND OF THE INVENTION
[0003] Conventional ice makers have an ice making compartment
located in proximity to, for example above, an ice storage
compartment. Ice is made during an ice making cycle in ice making
compartment. The ice is transferred by gravity action to ice
storage compartment during an ice harvest cycle.
[0004] The ice making compartment includes an evaporator that is
operable during the ice making cycle to make ice cubes.
[0005] Conventional evaporators include an array of ice cells, an
evaporator tube and a water drip tube. Typically, the evaporator
tube is connected to a compressor and condenser assembly and the
water drip tube is connected to a water supply system all of which
are conventional for ice makers (see U.S. Pat. No. 6,247,318, which
is incorporated herein in its entirety).
[0006] The ice cells of the array are preferably arranged in a grid
or matrix configuration having a plurality of horizontal rows and a
plurality of vertical columns. Optionally, disposed directly behind
the array is another array of ice cells, which is a mirror image of
the first array. The pair of arrays are formed by a plurality of
integral vertical structures that are interleaved with a plurality
of vertical partitions. Thus, a vertical column is formed with an
integral vertical structure and two vertical partitions that are
disposed on either side thereof.
[0007] During the ice making cycle, refrigerant is circulated
through the evaporator tube to the cool ice cells. Water drips from
the drip tube into the ice cell arrays. The dripping water trickles
through the arrays and freezes to gradually develop an ice cube in
each ice cell. During the harvest cycle, refrigerant from the
discharge side of the system is circulated in the evaporator tube.
This results in a slight melting of each ice cube that allows the
ice cube to loosen from its ice cell and fall into the storage
compartment or bin.
[0008] This prior art method of harvesting the ice represents a
loss in ice making efficiency due to: (a) the amount of ice that is
melted during the harvesting operation caused by the excess heat
provided by the hot gas in the evaporator, (b) the time it takes to
perform the harvest operation--such time not being available to
make ice, and (c) the excess heating of the evaporator--such heat
having to be removed from the evaporator during the subsequent ice
making cycle.
[0009] Hence, there is a strong demand for an ice making machine
which avoids the aforementioned deficiency and provides an ice
making machine whereby the ice formed in ice making cells can be
removed quickly and efficiently minimizing excess meltage of the
ice, removing the ice more quickly than is possible with a hot gas
defrost, and avoiding any excess heating of evaporator or ice
making cells.
[0010] In addition, ice making structures (i.e., evaporators) have
been traditionally fabricated from thermally conductive materials,
such as copper and nickel-plated copper. The present disclosure
utilizes a novel conductive plastics material for formation of the
evaporator and pulse electric thermal deicing (PETD) to harvest ice
using a novel short-duration resistance heater.
SUMMARY OF THE INVENTION
[0011] An ice making machine comprising: a thermally conductive
plastic evaporator assembly comprising an array of ice forming
surfaces; a water supply, a refrigerant supply and an electrical
energy source; and a controller that during a freeze mode operates
the water supply and the refrigerant supply to form ice on the ice
forming surfaces and during a harvest mode operates the electrical
energy source to apply electrical resistance energy (e.g., pulse
energy) to the evaporator assembly to melt an interfacial layer of
the ice such that it is freed from the surfaces.
[0012] The evaporator assembly comprises a thermally conductive
plastic base portion and a heater, wherein the heater is affixed to
a surface of the thermally conductive plastic base portion, such
that the heater is disposed between the ice and the base
portion.
[0013] The heater comprises a flexible membrane and an electrical
trace disposed on the flexible membrane. The thermally conductive
plastic base portion and the heater form an ice cell which is
capable of forming ice shapes. The heater is affixed to the
thermally conductive plastic base portion by at least one selected
from the group consisting of: adhesive, solvent bonding, ultrasonic
bonding, and heat fusing.
[0014] A method of making ice with an ice making machine that
comprises a thermally conductive plastic evaporator assembly
comprising an array of ice forming surfaces, a water supply, a
refrigerant supply and an electrical energy source, the method
comprising: during a freeze mode operating the water supply and the
refrigerant supply to form ice on the ice forming surfaces; and
during a harvest mode operating the electrical energy source to
apply electrical resistance energy (e.g., pulse energy) to the
evaporator assembly to melt an interfacial layer of the ice such
that it is freed from the surfaces.
[0015] An evaporator assembly for forming ice, the assembly
comprising: a thermally conductive plastic base portion and a pulse
electric thermal deicing heater, wherein the heater is affixed to a
surface of the thermally conductive plastic base portion, such that
the heater is disposed between the ice and the base portion.
[0016] Another embodiment includes an ice making machine
comprising: an evaporator assembly comprising at least one freezing
tube and at least two thermally conductive plastic or metal
evaporator plates, wherein the freezing tube is disposed between
oppositely disposed evaporator plates; at least one refrigerant
conduit disposed within the thermally conductive plastic or metal
evaporator plates; a water supply in communication with an inlet
port of the freezing tube; a refrigerant supply in communication
with the refrigerant conduit; an electrical energy source in
communication with the freezing tube; and a controller that during
a freeze mode operates the water supply and the refrigerant supply
to form ice on an interior surface of the freezing tube and during
a harvest mode operates the electrical energy source to apply
electrical resistance energy (e.g., pulse energy) to the freezing
tube or to a heater disposed about the freezing tube to melt an
interfacial layer of the ice formed on the interior surface of the
freezing tube such that it is freed from the interior surface.
[0017] The evaporator plate preferably comprises at least first and
second thermal transfer nodes which are spaced apart from one
another and in thermal contact with an outer surface the freezing
tube, thereby forming ice on the interior surface of the freezing
tube at a location defined by contacting of the thermal transfer
nodes and the freezing tube.
[0018] The evaporator further comprises a thermal insulation layer
or thermal break disposed about the exterior surface of the
freezing tube, such that ice is not formed on the interior surface
of the freezing tube at a location where the thermal transfer nodes
are insulated from the freezing tube.
[0019] A method of making ice with an ice making machine that
comprises an evaporator assembly comprising at least one freezing
tube and at least two thermally conductive plastic or metal
evaporator plates, wherein the freezing tube is disposed between
oppositely disposed evaporator plates, a water supply, a
refrigerant supply and an electrical energy source, the method
comprising: during a freeze mode operating the water supply and the
refrigerant supply to form ice on an interior surface of the
freezing tube; and during a harvest mode operating the electrical
energy source to apply electrical resistance energy (e.g., pulse
energy) to the freezing tube to melt an interfacial layer of the
ice such that it is freed from the interior surface of the freezing
tube.
[0020] An evaporator assembly for forming ice, the assembly
comprising: at least one freezing tube; at least two thermally
conductive plastic or metal evaporator plates, wherein the freezing
tube is disposed between oppositely disposed evaporator plates; a
refrigerant conduit disposed substantially within the evaporator
plate; and an energy source connected to or disposed about the
freezing tube for applying electrical resistance energy (e.g.,
pulse energy) to the freezing tube or to a heater disposed about
the freezing tube, thereby melting an interfacial layer of the ice
formed on the interior surface of the freezing tube such that it is
freed from the interior surface.
[0021] Still yet another embodiment of the present disclosure is an
ice making machine comprising: an evaporator assembly comprising at
least one freezing tube and at least two thermally conductive
plastic or metal evaporator segments, wherein the freezing tube is
disposed between oppositely disposed evaporator segments; at least
one refrigerant conduit disposed substantially perpendicularly
through the thermally conductive plastic or metal evaporator
segments; a water supply in communication with an inlet port of the
freezing tube; a refrigerant supply in communication with the
refrigerant conduit; an electrical energy source in communication
with the freezing tube; and a controller that during a freeze mode
operates the water supply and the refrigerant supply to form ice on
an interior surface of the freezing tube and during a harvest mode
operates the electrical energy source to apply electrical
resistance energy (e.g., pulse energy) to the freezing tube or to a
heater disposed about the freezing tube to melt an interfacial
layer of the ice formed on the interior surface of the freezing
tube such that it is freed from the interior surface.
[0022] Preferably the evaporator segment comprises at least first
and second thermal transfer nodes which are spaced apart from one
another and in thermal contact with an outer surface the freezing
tube, thereby forming ice on the interior surface of the freezing
tube at a location defined by contacting of the thermal transfer
nodes and the freezing tube.
[0023] Furthermore, the evaporator comprises a thermal insulation
layer disposed about the exterior surface of the freezing tube,
such that ice is not formed on the interior surface of the freezing
tube at a location where the thermal transfer nodes are not in
direct contact with the freezing tube.
[0024] A method of making ice with an ice making machine that
comprises an evaporator assembly comprising at least one freezing
tube and at least two thermally conductive plastic or metal
evaporator segments, wherein the freezing tube is disposed between
oppositely disposed evaporator segments, a water supply, a
refrigerant supply and an electrical energy source, the method
comprising: during a freeze mode operating the water supply and the
refrigerant supply to form ice on an interior surface of the
freezing tube; and during a harvest mode operating the electrical
energy source to apply electrical resistance energy (e.g., pulse
energy) to the freezing tube to melt an interfacial layer of the
ice such that it is freed from the interior surface of the freezing
tube.
[0025] An evaporator assembly for forming ice, the assembly
comprising: at least one freezing tube; at least two thermally
conductive plastic or metal evaporator segments, wherein the
freezing tube is disposed between oppositely disposed evaporator
segments; a refrigerant conduit disposed substantially
perpendicular to the evaporator segments; and an energy source
connected to or disposed about the freezing tube for applying
electrical resistance energy (e.g., pulse energy) to the freezing
tube or to a heater disposed about the freezing tube, thereby
melting an interfacial layer of the ice formed on the interior
surface of the freezing tube such that it is freed from the
interior surface.
[0026] Another embodiment includes an ice making machine
comprising: an evaporator assembly comprising a freezing tube, a
shell disposed about the freezing tube, a plurality of insulating
rings disposed at spaced apart longitudinal locations about the
length of the freezing tubes, and refrigerant inlet and outlet
ports disposed within a sidewall of the shell; a water supply in
communication with an inlet port of the freezing tube; a
refrigerant supply in communication with the refrigerant inlet
port; an electrical energy source in communication with the
freezing tube; and a controller that during a freeze mode operates
the water supply and the refrigerant supply to form ice on an
interior surface of the freezing tube and during a harvest mode
operates the electrical energy source to apply electrical
resistance energy (e.g., pulse energy) to the freezing tube to melt
an interfacial layer of the ice formed on the interior surface of
the freezing tube such that it is freed from the interior
surface.
[0027] A method of making ice with an ice making machine that
comprises an evaporator assembly comprising a freezing tube, a
shell disposed about the freezing tube, a plurality of insulating
rings disposed at spaced apart longitudinal locations about the
length of the freezing tube, and refrigerant inlet and outlet ports
disposed within a sidewall of the shell, a water supply, a
refrigerant supply connected to the refrigerant inlet port, and an
electrical energy source, the method comprising: during a freeze
mode operating the water supply and the refrigerant supply to form
ice on an interior surface of the freezing tube; and during a
harvest mode operating the electrical energy source to apply
electrical resistance energy (e.g., pulse energy) to the freezing
tube to melt an interfacial layer of the ice such that it is freed
from the interior surface of the freezing tube.
[0028] An evaporator assembly for forming ice, the assembly
comprising: a freezing tube; a shell disposed about the freezing
tube; a plurality of insulating rings disposed at spaced apart
longitudinal locations about the length of the freezing tube; and
refrigerant inlet and outlet ports disposed within a sidewall of
the shell; and an energy source connected to or disposed about the
freezing tube for applying electrical resistance energy (e.g.,
pulse energy) to the freezing tube, thereby melting an interfacial
layer of the ice formed on the interior surface of the freezing
tube such that it is freed from the interior surface.
[0029] Still another embodiment includes an ice making machine
comprising: an evaporator assembly comprising a plurality of
freezing tubes, a shell disposed about the freezing tubes, a
plurality of insulating rings disposed at spaced apart longitudinal
locations about the length of each the freezing tubes, and
refrigerant inlet and outlet ports disposed within a sidewall of
the shell; a water supply in communication with an inlet port of
each the freezing tube; a refrigerant supply in communication with
the refrigerant inlet port; an electrical energy source in
communication with each of the freezing tubes; and a controller
that during a freeze mode operates the water supply and the
refrigerant supply to form ice on an interior surface of the
freezing tubes and during a harvest mode operates the electrical
energy source to apply electrical resistance energy (e.g., pulse
energy) to the freezing tubes to melt an interfacial layer of the
ice formed on the interior surface of the freezing tube such that
it is freed from the interior surface.
[0030] A method of making ice with an ice making machine that
comprises an evaporator assembly comprising a plurality of freezing
tubes, a shell disposed about the freezing tubes, a plurality of
insulating rings disposed at spaced apart longitudinal locations
about the length of each the freezing tubes, and refrigerant inlet
and outlet ports disposed within a sidewall of the shell, a water
supply, a refrigerant supply connected to the refrigerant inlet
port, and an electrical energy source, the method comprising:
during a freeze mode operating the water supply and the refrigerant
supply to form ice on an interior surface of the freezing tubes;
and during a harvest mode operating the electrical energy source to
apply electrical resistance energy (e.g., pulse energy) to the
freezing tubes to melt an interfacial layer of the ice such that it
is freed from the interior surface of the freezing tubes.
[0031] An evaporator assembly for forming ice, the assembly
comprising: a water supply, a plurality of freezing tubes; a shell
disposed about the freezing tubes; a plurality of insulating rings
disposed at spaced apart longitudinal locations about the length of
each the freezing tubes; and refrigerant inlet and outlet ports
disposed within a sidewall of the shell; and an energy source
connected to or disposed about the freezing tubes for applying
electrical resistance energy (e.g., pulse energy) to the freezing
tubes, thereby melting an interfacial layer of the ice formed on
the interior surface of the freezing tubes such that it is freed
from the interior surface.
[0032] The ice making machine of the present disclosure comprises a
water supply, a refrigerant supply, an electrical energy source
(e.g., PETD), a controller and a thermally conductive plastic
evaporator assembly that comprises an array of ice forming
surfaces. During a freeze mode, the controller operates the water
supply and the refrigerant supply to form ice on the ice forming
surfaces. During a harvest mode, the controller operates the
electrical energy source to apply electrical resistance energy
(e.g., pulse energy) to the evaporator assembly to melt an
interfacial layer of the ice such that it is freed from the
surfaces.
[0033] A method of the present disclosure makes ice with an ice
making machine that comprises a thermally conductive plastic
evaporator assembly comprising an array of ice forming surfaces, a
water supply, a refrigerant supply and an electrical energy source.
The method comprises in a freeze mode operating the water supply
and the refrigerant supply to form ice on the ice forming surfaces
and in a harvest mode operating the electrical energy source to
apply electrical resistance energy (e.g., pulse energy) to the
evaporator assembly to melt an interfacial layer of the ice such
that it is freed from the surfaces.
[0034] In one embodiment of the method of the present disclosure,
the thermally conductive plastic evaporator assembly comprises an
ice mold that comprises at least one of the ice forming surfaces.
The electrical resistance energy (e.g., pulse energy) is applied to
a member of the group consisting of: the ice mold and an
electrically conductive element that is in thermal transfer
relation to the ice mold.
[0035] Yet another embodiment of the present disclosure, includes
an ice making machine comprising: an evaporator assembly comprising
a helical tube, said helical tube comprising a freezing tube and at
least one refrigerant conduit disposed about said freezing tube; a
water supply in communication with an inlet port of said freezing
tube; a refrigerant supply in communication with refrigerant
conduit; an electrical energy source in communication with said
freezing tube; and a controller that during a freeze mode operates
said water supply and said refrigerant supply to form ice on an
interior surface of said freezing tube and during a harvest mode
operates said electrical energy source to apply electrical
resistance energy (e.g., pulse energy) to said freezing tube to
melt an interfacial layer of said ice formed on said interior
surface of said freezing tube such that it is freed from said
interior surface.
[0036] A method of making ice with an ice making machine that
comprises an evaporator assembly comprising a helical tube, said
helical tube comprising a freezing tube and at least one
refrigerant conduit disposed about said freezing tube, a water
supply, a refrigerant supply connected to said refrigerant conduit,
and an electrical energy source, said method comprising: during a
freeze mode operating said water supply and said refrigerant supply
to form ice on an interior surface of said freezing tube; and
during a harvest mode operating said electrical energy source to
apply electrical resistance energy (e.g., pulse energy) to said
freezing tube to melt an interfacial layer of said ice such that it
is freed from said interior surface of said freezing tube.
[0037] An evaporator assembly for forming ice, said assembly
comprising: a helical tube, said helical tube comprising a freezing
tube and at least one refrigerant conduit disposed about said
freezing tube; and an energy source connected to or disposed about
said freezing tube for applying electrical resistance energy (e.g.,
pulse energy) to said freezing tube, thereby melting an interfacial
layer of said ice formed on said interior surface of said freezing
tube such that it is freed from said interior surface.
[0038] The present disclosure provides for modifying the interface
between ice and the structure in which it is formed, by melting the
interfacial layer that binds ice and the structure on which it is
formed, thereby enhancing ice release and harvest. It also includes
a method of applying an electrical conductive pathway to an ice
forming structure at the interfacial layer of the structure. More
preferably, the present disclosure provides a method of applying a
resistance heater to an ice forming structure that (a) maintains
thermal conductivity between the ice forming structure and the ice;
and (b) electrically isolates (PETD) energy charge from the ice
forming structure. The present disclosure also provides various
methods for isolating the electrical charge from the ice forming
structure, thereby minimizing energy consumption and time needed to
melt the interfacial boundary. It also provides a method for
applying an electrical conductive pathway incorporating (a) and
(b), above, to an ice forming structure that is inexpensive and
readily manufacturable. According to the present disclosure the ice
forming structure (i.e., evaporator) is formed using thermally
conductive materials, including, but not limited to, thermally
conductive plastics.
[0039] Furthermore, the present disclosure includes a method of
manufacturing ice forming structures with discrete ice-forming
regions (i.e., pocket, cells, fingers, etc.) using thermally
conductive plastics.
[0040] Additionally, a method is provided for selectively applying
electrical energy to ice-forming regions that releases ice
sequentially or simultaneously.
[0041] Furthermore, a method is provided that applies an electrical
conductive pathway with varying (heat or electrical) energy
densities, thereby enabling selective heating of the interfacial
boundary between ice and the ice-forming structure. Another method
provides for integrating electrical conductive pathways to ice
forming structures with ice forming regions having complex shapes
and contours. Preferably, the ice forming structure incorporates
electrically isolated energy contact points.
[0042] Furthermore, the ice forming structure may be formed such
that it is made of individual modules or segments, that when
combined, provide scalable ice making capacities. The ice forming
structure having ice forming regions on both sides of the structure
(i.e., evaporator), thereby increasing the ice making capacity.
BRIEF DESCRIPTION OF THE DRAWINGS
[0043] Other and further objects, advantages and features of the
present disclosure will be understood by reference to the following
specification in conjunction with the accompanying drawings, in
which like reference characters denote like elements of structure
and:
[0044] FIGS. 1(a)-(c) is a schematic representation of a flexible
membrane element (a) that can be folded before insertion molded
into an evaporator (b), as depicted in (c) according to the present
disclosure;
[0045] FIG. 2 is a schematic representation of a flexible membrane
heater element configured for individual ice forming cells;
[0046] FIG. 3 is a schematic representation of a front left side
perspective view of a thermally conductive plastic evaporator
within an ice making system according the present disclosure having
individual ice forming cells of FIG. 2;
[0047] FIG. 4 is a cross-section view along line 3-3 of FIG. 3
depicting the evaporator tubes disposed internally of the thermally
conductive plastic evaporator;
[0048] FIG. 5a is a schematic representation of a perspective view
of another embodiment according to the present disclosure having
freezing tubes disposed within a thermal conductive plastic
evaporator; wherein the freezing tubes are thin wall stainless
tubes which are electrically isolated from the evaporator allowing
for the application of resistance heating to the entire evaporator
during harvest mode;
[0049] FIG. 5b is a schematic representation of a perspective view
of another embodiment according to the present disclosure having
freezing tubes disposed within a thermal conductive plastic
evaporator; wherein the freezing tubes are thin wall stainless
tubes with membrane heaters wrapped around each tube for
simultaneous resistance heating of each tube individually;
[0050] FIG. 6a is a schematic representation of a perspective view
of another embodiment according to the present disclosure having
freezing tubes disposed within a thermal conductive extruded
aluminum evaporator; wherein the freezing tubes are thin wall
stainless tubes which are electrically isolated from the evaporator
allowing for the application of resistance heating to the entire
evaporator during harvest mode;
[0051] FIG. 6b is a schematic representation of a perspective view
of another embodiment according to the present disclosure having
freezing tubes disposed within a thermal conductive extruded
aluminum evaporator; wherein the freezing tubes are thin wall
stainless tubes with membrane heaters wrapped around each tube for
simultaneous resistance heating of each tube individually;
[0052] FIG. 7a is a schematic representation of a perspective view
of still another embodiment according to the present disclosure
having an individual shell and tube configuration;
[0053] FIG. 7b is a schematic representation of a perspective view
of another embodiment according to the present disclosure having
multiple shell and tubes with membrane heaters disposed about each
shell and tube;
[0054] FIG. 8 is a schematic representation of a shell and tube
evaporator according to the present disclosure;
[0055] FIG. 9 is a schematic representation of the shell and tube
evaporator according to FIG. 8 as disposed within an ice making
assembly according to the present disclosure; and
[0056] FIG. 10 is a schematic representation of a cross-section of
a helical tubular extruded aluminum ice making evaporator according
to still another embodiment of the present disclosure.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0057] The present disclosure encompasses the use of thermally
conductive plastic and/or extruded aluminum evaporator plates or
ice-forming tubes, and the application of a short-duration
electrical resistance heater, e.g., pulse electric thermal deicing
(PETD) to ice-forming structures (i.e., evaporators or ice-forming
tubes). The short-duration electrical pulse is in the range between
about 0.1 microsecond to 10 seconds, preferably between about 0.1
microsecond to 3 seconds, and most preferably between about 1 to 3
seconds. The shorter the electric pulse, the higher the energy
input required to harvest the ice.
[0058] Preferably, the ice-forming surfaces are electrically
isolated from the refrigeration components. According to the
present disclosure, PETD energy is applied to an ice-forming
structure in such a way as to not energize the entire ice making
structure or other conductive refrigeration components which would
otherwise require significant energy inputs or otherwise make the
system unsafe from electrical shock.
[0059] As depicted in FIGS. 3 and 4, an ice making machine 30
comprises a waffle-style, thermally conductive plastic evaporator
assembly 32, a water supply 34, a refrigerant supply 36, a
controller 38, an ice bin 39 and a source 40 of pulsed electrical
energy, e.g., PETD. Evaporator assembly 32 comprises ice mold 1 and
evaporator tube 3. Evaporator tube 3 is interconnected with
refrigerant supply 36. The water valve is interconnected with water
supply 34. Controller 38 controls the freezing and harvesting
cycles by appropriately controlling the pulsed electrical energy,
the flow of water and refrigerant to evaporator assembly 32.
[0060] Referring to FIG. 3 an ice-making system 30 comprising a
molded-in membrane heater with use in a dual-sided waffle-style
pulse electric evaporator using thermally conductive plastic and
inlaid electric trace. The system also comprises electrical energy
source 40 which is connected in circuit with evaporator tube 3,
which is constructed of electrically conductive material. For
example, evaporator tube may be made of metal, such as copper,
aluminum or steel. Electrical energy source 40 is connected via an
electrical connector 42 to a contact point 44 of thermally
conductive plastic or extruded aluminum ice mold 1 and via an
electrical connector (not shown) to a circuit reference, e.g.,
circuit ground.
[0061] In accordance with the present disclosure, electrical energy
source 40 is operable at the time of harvest to apply one or more
pulses of electric energy to thermally conductive plastic or
extruded aluminum mold 1 to melt an interfacial layer of the ice at
the interface of the ice and mold 1 sufficiently to loosen the ice
so that it falls into ice bin 39.
[0062] Electrical energy source 40 and the pulsed energy used for
thermal de-icing, for example, may be of the type described in U.S.
Pat. No. 6,870,139, U.S. Patent Publication No. 2005/0035110, and
U.S. Patent Publication No. 2004/0149734, all of which are
incorporated herein in their entirety by reference thereto, that is
capable of supplying pulsed energy. Modulating the pulsed energy to
the interface of the ice to ice mold 1 modifies a coefficient of
friction between the ice and ice mold 1. The electrical pulse
energy technology is known as Pulse Electro Thermal De-icing
(PETD).
[0063] Typically, a pulse de-icer system heats an interface to a
surface of an object so as to disrupt adhesion of ice with the
surface. To reduce the energy requirement, one embodiment of a
pulse de-icer explores a very low speed of heat propagation in
non-metallic solid materials, including ice, and applies heating
power to the interface for time sufficiently short for the heat to
escape far from the interface zone; accordingly, most of the heat
is used to heat and melt only a very thin layer of ice (hereinafter
"interfacial ice"). The system preferably includes a power supply
configured to generate a magnitude of power. In one aspect, the
magnitude of the power has a substantially inverse-proportional
relationship to a magnitude of energy used to melt ice at the
interface. The pulse de-icer system may also include a controller
configured to limit a duration in which the power supply generates
the magnitude of the power. In one aspect, the duration has a
substantially inverse-proportional relationship to a square of the
magnitude of the power. The power supply may further include a
switching power supply capable of pulsing voltage. The pulsed
voltage may be supplied by a storage device, such as a battery or a
capacitor. The battery or capacitor can, thus, be used to supply
power to a heating element that is in thermal communication with
the interface.
[0064] A preferred pulse de-icer systems is hereafter described.
This pulse de-icer system may be used to remove ice from a surface
of an object such as a ice forming cup or finger, typically by
melting an interfacial layer of ice and/or modifying a coefficient
of friction of an object-to-ice interface.
[0065] One such pulse de-icer system for modifying an interface
between an evaporator assembly and ice according to the present
disclosure comprises: a power supply, a controller, and a heating
element. In one embodiment, the power supply is configured for
generating power with a magnitude that is substantially inversely
proportional to a magnitude of energy used to melt interfacial ice
(hereinafter "interfacial ice") at the interface. A heating element
is coupled to the power supply to convert the power into heat at
the interface. Controller is coupled to the power supply to limit a
duration in which the heating element converts the power into heat.
In one embodiment, the duration in which the heating element
converts the power into heat at the interface is substantially
inversely proportional to a square of the magnitude of the
power.
[0066] Controller 38 controls electrical energy source 40 to apply
electrical pulse energy when the ice mold 1 has grown to the
desired predetermined size. The electrical pulse energy causes
electrical resistance heating of mold 1 by thermal conduction from
mold 1. The fast, even heating of molds 1 releases the ice within
molds 1 more quickly than with the prior art defrost methods,
minimizes the amount of melting that occurs.
[0067] From the foregoing it may be seen that the arrangement of
the present disclosure provides an automatic ice making machine in
which harvesting of the ice is achieved very quickly and in a very
energy-efficient manner.
[0068] FIGS. 1(a)-(c) and 2 depict a geometry and design of a
short-duration pulsed, resistive heater 10 comprising an
electrically conductive material 12 (i.e., metallic foil,
di-electric media, electrically conductive inks, etc.) that can be
applied to a thermally conductive/thermally isolative substrate
(e.g., a plastic film) (not shown) such that the heater element 14
can be patterned (i.e., die-cut) and contoured (i.e., folded, bent,
rolled, curved, etc.) in order to come in intimate contact with the
surface of the ice-forming regions of the ice-forming structure.
FIGS. 1 and 2 depict two types of short-duration, resistive heaters
that are thermally conductive and electrically isolated such that
the material 12 permanently attaches (e.g., adhesive, solvent bond,
ultrasonically bonded or heat fused) to the ice-forming structure
(i.e., evaporator) at the interfacial boundary layer of the ice and
the surface of the ice-forming structure.
[0069] In particular, FIGS. 1(a)-(c) depicts a mold-in membrane
heater 10 with a flexible membrane element 12 having a width of
between about 0.003 to 0.005 inches. Flexible membrane element 12
is preferably formed of a material which is capable of bonding to a
thermally conductive plastic evaporator, not shown. Each flexible
membrane element 12 include electrical trace 14 having a positive
and negative connection at opposite ends thereof. Membrane heater
10 is also capable of being folded prior to insert molding into the
evaporator, not shown. After insert molding of membrane heater 10
into the evaporate, the two pieces are bonded or fused together to
form a integral one-piece evaporator with integral heat interface.
FIGS. 1(b) and (c) depict two different type shapes of membrane
heater 10 for forming individual ice cells.
[0070] Membrane heater 10 can be an etched foil design element
disposed on a Kapton.RTM./Polyimide heater. Heaters made with this
DuPont thin film are transparent, lightweight, flexible and are
electrically strong. Kapton.RTM./Polyimide heaters are compatible
with foil element alloys, such as inconel, nickel, copper and
stainless steel. They have low outgassing properties, are resistant
to solvents and can be produced with special internal adhesive
systems that permit higher operating temperatures.
[0071] FIG. 5(a) depicts a thermal conductive plastic or cast
aluminum evaporator 49, according to the present disclosure, with a
plurality of thin wall stainless freezing or ice forming tubes 52
disposed therethrough. Each tube 52 is disposed between stacked
evaporator plates 50, wherein tubes 52 are electrically isolated
from evaporator 49. The sandwiching of freezing tubes 52 between
successive layers of evaporator plates 50 enables scalable ice
making capacities and thinner wall tubes (since there is no direct
refrigerant pressure on tubes 52). In addition each evaporator
plate 50 includes thermal transfer nodes 60 which contact tubes 52
intermittently. Thermal transfer nodes 60 preferentially contact
freezing tubes 52 intermittently to form individual ice slugs
rather than a continuous ice layer throughout the entire length of
each tube 52. Tubes 52 include low-mil electrical insulation 62
about their outer surfaces. Freezing tubes 52 are preferably
thin-walled (i.e., emulates properties of foil) to disrupt ice
adhesion at the interfacial layer of ice and tube 52.
[0072] In-molded copper tubing 54 is formed within each evaporator
plate 50 such that refrigerant enters inlet 56 and exits via outlet
58 of tubing 54.
[0073] Water enters tubes 52 via inlet ports 64 during an ice
making harvest an electrical pulse is sent via PETD electrical
contact 66, thereby releasing ice slugs from the inner surface of
each tube 52 which exit via outlet ports 68.
[0074] The benefit to the embodiment of FIG. 5(a) is that freezing
tubes 52 are electrically isolated from evaporator contacts 66 and
therefore can be electrical-resistance heated directly without
energizing the entire ice making system, not shown.
[0075] FIG. 5(b) has most of the same components as FIG. 5(a)
above, with the exception that it utilizes, according to another
embodiment of the present disclosure, thin wall stainless tubes 70
with membrane heaters 72 disposed about the outer surface of tubes
70. The membrane heaters 72 are low mil thickness and provide
electrical resistance heat or pulsed energy via electrical contacts
74. That is, FIG. 5(b) is the same as FIG. 5(a), but instead of
electrically pulsing the freezing tubes directly, a membrane heater
element 62 is wrapped around each freezing tube 52 and pulsed. This
approach momentarily heats tubes 52 (from outside-in) to disrupt
ice adhesion at the interfacial layer and release the ice.
[0076] Freezing tubes 52 can be sequentially pulsed, or pulsed
simultaneously.
[0077] FIGS. 6(a) and (b) are similar in function to FIGS. 5(a) and
(b), respectively, however, the configuration is slightly
different. In FIG. 6(a) there is an extruded aluminum evaporator
segments 80 stacked one on top of the other, wherein copper tube 82
are disposed in a vertical, serpentine configuration through a
plurality of segments 80. Thin wall stainless steel freezing tubes
84 are also positioned vertically through segments 80. Tubes 82
include a low-mil electrical insulation 86 and are disposed between
segments 80 within thermal transfer nodes 88 which contact tubes 82
intermittently for the purposes of producing ice slugs as discussed
above. During operation, water enters inlet port 90 of each
freezing tube 84 where it freezes on the interior surface of tube
84, preferably at the point of contact between tube 84 and thermal
transfer node 88, such that ice slugs exit outlet port 92 during
harvest by means of an electric pulse being generated on the tube
84 via electric contacts 96.
[0078] In FIG. 6(a) freezing tubes 84 are electrically isolated
from evaporator segments 80 and therefore can be electro-thermally
pulsed directly without energizing the entire ice-making
system.
[0079] FIG. 6(b) is similar to FIG. 6(a), except that it provides
for a membrane heater 98 wrapped about the exterior walls of each
freezing tube 84, such that during the harvest mode and electric
pulse is transferred to the membrane heater 98 via electrical
contacts 100. That is, instead of electrically pulsing freezing
tube 84 directly, as in FIG. 6(a), a membrane heater element 98 is
wrapped around each freezing tube and pulsed. This approach
momentarily heats freezing tube 84 (from outside-in) to disrupt ice
adhesion at the interfacial layer and releases the ice.
[0080] Like in FIGS. 5(a) and (b), freezing tubes 84 can be
sequentially pulsed, or pulsed simultaneously.
[0081] The evaporator plates of FIGS. 6(a) and (b) comprise a
plurality of individual extruded or cast aluminum segments 80
stacked with air space in between each successive segment 80. Ice
freezing tubes 84 are then sandwiched between these assemblies
providing intimate contact at thermal transfer nodes 88. Thermal
transfer nodes 88 which are formed during the extrusion or casting
process enables scalable ice making capacities and thinner wall
tubes since there is no refrigerant pressure on tubes 84.
[0082] FIGS. 7(a) through 9 depict another embodiment according to
the present disclosure, i.e., a shell and tube configuration. FIG.
7(a) depicts an individual shell and tube device 110, whereas FIG.
7(b) depicts a evaporator assembly 120 comprising an assembly
comprising multiple shell and tubes 122.
[0083] In FIG. 7(a) a shell and tube device 110 comprises a
freezing tube 112 disposed within shell 114. Shell 114 includes
refrigerant inlet 115 and outlet 116. During the ice making mode,
water enters tube 112 at water inlet 117 and refrigerant enters
refrigerant inlet 115, such that ice forms about the interior
surface of tube 117 at location where insulation rings 118 are not
in contact with the exterior surface of tube 117. During the
harvest mode, electrical pulse energy is driven into tube 117 via
electrical contact 119, such that ice slugs exit tube 117 via exit
port 121.
[0084] In FIGS. 7(b) and 8 a plurality of tubes 122 disposed within
a large shell 124. Each freezing tube 122 having a water inlet 126
and outlet 128. Each shell has a refrigerant inlet 130 and out 132.
The freezing tubes are include membrane heaters 134 disposed about
each tube 122, which are electrically connected to an PETD
electrical pulse source (not shown) via electrical contact 136. An
electric conduit (not shown) connects said electrical contact 136
with electrical pulse source (not shown) via conduit 138 disposed
in an upper plate 140 of shell 124. Insulating rings 142 are
disposed about each tube 122, such that during the ice making mode
ice forms only about that portion of freezing tubes 122, which are
exposed to the refrigerant within shell 124 and not insulated by
means of insulating rings 142. During the harvest mode, an
electrical energy pulse is delivered to membrane heaters 134
disposed about tubes 122, such that ice slugs are removed via
outlet ports 128 shortly after activation of the electrical energy
pulse.
[0085] FIG. 9 depicts a ice making system 150 comprising the shell
and tube assembly 120 of FIGS. 7(b) and 8, wherein water from sump
152 is transported via conduit 154 and pump 156 from sump 152 to a
top portion 158 of shell and tube assembly 120, where it enters
each water inlet port 126. During the harvest mode ice slugs leave
shell and tube assembly 120 via exit ports 128 for collection
within ice bin 160.
[0086] Still another embodiment according to the present disclosure
is depicted in FIG. 10 which shows a cross-sectional view of
helical tubular extruded aluminum ice making evaporator comprising
freezing tube 170 having a water conduit or channel 171, and
refrigeration passages 172 and 174 disposed on opposite side
thereof. Preferably, freezing tube 170 is coiled into a helix (not
shown), wherein water is introduced into an upper end of the helix
and exits the lower end of the helix. Ice freezes from the
outside-in as it is cooled by the refrigerant passing through
refrigeration passages 172 and 174. When the water conduit or
channel 171 has become plugged by ice, PETD pulse is applied to at
least a portion of the length of tube 170, wherein the ice is
related from the interior surface of the freezing tube 170 and is
ejected from tube 170 by either gravity or water pressure.
[0087] The present disclosure having been thus described with
particular reference to the preferred forms thereof, it will be
obvious that various changes and modifications may be made therein
without departing from the spirit and scope of the present
disclosure as defined in the appended claims.
* * * * *