U.S. patent application number 13/194257 was filed with the patent office on 2012-02-09 for method and system for producing clear ice.
This patent application is currently assigned to MANITOWOC FOODSERVICE COMPANIES, LLC. Invention is credited to Daryl G. Erbs, Lee Gerard Mueller.
Application Number | 20120031114 13/194257 |
Document ID | / |
Family ID | 45544851 |
Filed Date | 2012-02-09 |
United States Patent
Application |
20120031114 |
Kind Code |
A1 |
Mueller; Lee Gerard ; et
al. |
February 9, 2012 |
METHOD AND SYSTEM FOR PRODUCING CLEAR ICE
Abstract
A method for making clear ice comprising: filling a water sump
to a predetermined level; contacting a refrigerant to an
evaporator; circulating water from the sump over the evaporator to
form ice on the evaporator; monitoring the water level in the sump;
and monitoring the conductivity of the water in the sump to
determine if the conductivity of the water is equal to or greater
than a predetermined conductivity valve, (i) if the conductivity is
not equal to or greater than the predetermined conductivity valve
and if the water level reaches a predetermined lower water level,
then complete the ice making cycle and initiate the harvest cycle;
or (ii) if the conductivity is equal to or greater than the
predetermined conductivity valve and if the water level has not
reached a predetermined lower water level, then add additional
water to the water sump.
Inventors: |
Mueller; Lee Gerard;
(Kewaunee, WI) ; Erbs; Daryl G.; (Sheboygan,
WI) |
Assignee: |
MANITOWOC FOODSERVICE COMPANIES,
LLC
|
Family ID: |
45544851 |
Appl. No.: |
13/194257 |
Filed: |
July 29, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61370422 |
Aug 3, 2010 |
|
|
|
Current U.S.
Class: |
62/66 ;
62/132 |
Current CPC
Class: |
G01F 23/24 20130101;
G01F 23/242 20130101; F25C 2400/14 20130101; F25C 1/18 20130101;
F25C 2700/04 20130101; F25C 2600/04 20130101 |
Class at
Publication: |
62/66 ;
62/132 |
International
Class: |
F25C 1/00 20060101
F25C001/00; F25B 49/00 20060101 F25B049/00 |
Claims
1. A method for making clear ice comprising: filling a water sump
to a predetermined level; contacting a refrigerant to an
evaporator; circulating water from said sump over said evaporator
to form ice on said evaporator; monitoring the water level in said
sump; and monitoring the conductivity of the water in said sump to
determine if the conductivity of said water is equal to or greater
than a predetermined conductivity valve, if the conductivity is not
equal to or greater than said predetermined conductivity valve and
if the water level reaches a predetermined lower water level, then
complete the ice making cycle and initiate the harvest cycle; or if
the conductivity is equal to or greater than said predetermined
conductivity valve and if the water level has not reached a
predetermined lower water level, then add additional water to said
water sump.
2. The method according to claim 1, if the ice making cycle has
ended and the conductivity of said water in said sump is not equal
to or greater than said predetermined valve, adding additional
water to said sump before initiating another ice making cycle.
3. The method according to claim 1, if the ice making cycle has
ended and the conductivity of the water in said sump is equal to or
greater than said predetermined conductivity valve, dumping said
water in said sump and adding freeze water to said sump before
initiating another ice making cycle.
4. The method according to claim 1, wherein step of monitoring said
water level is via a water level probe comprising a first probe for
detecting a high water level and second and third probes for
detecting a low water level.
5. The method according to claim 4, wherein said water level probe
measures said conductivity of said water by determining the
conductivity difference between said second and third probes,
wherein said third probe is a reference probe.
6. The method according to claim 1, wherein said predetermined
conductivity value is about 30 GPH.
7. A system for producing clear ice, said system comprising: a
water supply; a water sump; an evaporator a water inlet valve
disposed between said water supply and said water sump; a pump for
circulating water from said sump to said evaporate during an ice
making cycle; a controller that monitors the water level in said
sump and the conductivity of the water in said sump to determine if
the conductivity of said water is equal to or greater than a
predetermined conductivity valve, if the conductivity is not equal
to or greater than said predetermined conductivity valve and if the
water level reaches a predetermined lower water level, then
complete the ice making cycle and initiate the harvest cycle; or if
the conductivity is equal to or greater than said predetermined
conductivity valve and if the water level has not reached a
predetermined lower water level, then add additional water to said
water sump.
8. The system according to claim 7, if the ice making cycle has
ended and the conductivity of said water in said sump is not equal
to or greater than said predetermined valve, said water inlet valve
is energized by said controller such that additional water from
said water supply is added to said sump.
9. The system according to claim 7, further comprising a water dump
valve such that if the ice making cycle has ended and the
conductivity of the water in said sump is equal to or greater than
said predetermined conductivity valve, said water dump valve is
energized by said controller such that said water in said sump is
dumped from the system before initiating another ice making
cycle.
10. The system according to claim 7, wherein said controller
further includes a water level probe comprising a first probe for
detecting a high water level and second and third probes for
detecting a low water level.
11. The system according to claim 10, wherein said water level
probe measures said conductivity of said water by determining the
conductivity difference between said second and third probes,
wherein said third probe is a reference probe.
12. The system according to claim 7, wherein said predetermined
conductivity value is about 30 GPH.
Description
CROSS-REFERENCED APPLICATIONS
[0001] This application claims priority to U.S. Provisional
Application No. 61/370,422, filed on Aug. 3, 2010, which is
incorporated herein by reference in its entirety.
BACKGROUND
[0002] 1. Field
[0003] The present disclosure generally relates to a method and
system for producing clear ice by monitoring the conductivity of
water (e.g., Total Dissolved Solids (TDS)) in an ice machine and
adding additional water when conductivity exceeds a predetermined
level, thereby reducing the TDS level of the water and enabling the
formation of clear ice. In particular, the present disclosure
provides for the formation of clear or clearer ice by monitoring or
detecting the conductivity of water to ensure that the TDS level of
the water is maintained below a predetermined level during the
freeze cycle by the addition of fresh water from the water
source.
[0004] 2. Discussion of the Background Art
[0005] It is know in the ice making industry that excessive TDS
concentrations in water can prevent the formation of ice cubes and
also product undesirable cloudy appearing ice cubes. In addition,
once of the causes for equipment failure in ice making and steaming
equipment is water-borne dissolved minerals commonly referred to as
TDS, measured in parts per million (ppm). Unacceptably large
concentrations of TDS interfere with machine operation while in
solution, and form deposits of unwanted scale when the water
changes phase. Scaling in ice makers can also result in increased
level of difficulty in harvesting ice cubes, as they will often
become stuck to the evaporator plate, and eventually may damage the
evaporator plate.
[0006] Furthermore, as TDS builds up in an icemaker, the pH of the
water also increases, which decreases the ability of minerals to
stay in solution. Thus, left unchecked, the scale forms
progressively faster.
[0007] Conventional icemakers address the problem of TDS buildup by
periodically flushing the water lines and other components during
the harvest phase of the cube formation cycle. In addition, the
storage sump, which retains a supply of chilled water recirculated
to form ice cubes, is also emptied at this time, either partially
or totally.
[0008] Other attempts to decrease TDS and scaling in the water
supply of ice makers, steamers and other water phase changing
devices include the use of more effective filters and the addition
of feed phosphates or acidulates to stop the buildup of minerals.
Although filtration is effective in substantially reducing
suspended particles, the ionic particles in solution in the water
are not significantly reduced. The addition of phosphates or acid
to filtered water has also been found to further prolong the
service interval as compared to filtration alone. The chemical
additives assist in maintaining the ionic particles in solution
longer. However, users of such equipment have still been forced to
dump excessive amounts of chilled water from their units.
[0009] Another drawback of conventional ice making equipment is
that the rate of scale buildup varies with the varying TDS
concentration in different types of water sources, the level of
water treatment, and the geographic region.
[0010] The problem with periodically flushing the water lines and
water in the sump is that it costs additional money in terms of
sewage disposal and new filtered water. This problem was addressed
in U.S. Pat. No. 5,527,470 (Suda) which is directed to a method for
monitoring and controlling an ice machine by monitoring the TDS
concentration of the recirculating water in the machine. If the TDS
has been determined to exceed a predetermined level, then after the
harvest cycle has been completed, the system will discharge all or
a portion of the water from the sump and then introduce new water.
Rather than discharging all of the water, as in some of the earlier
attempts to regulated TDS in ice making water, Suda attempts to
discharge only a portion and then adds only enough refresh water to
insure that the sump water is below the predetermined TDS level.
Unfortunately, this is still wasteful, results in cloudy ice and
not ecologically desirable. That is, once the ice making machine of
Suda initiates the freeze cycle is utilizes whatever water is
presently in the sump to make ice regardless of its TDS level
during the freeze cycle. However, as the ice begins to form, the
present inventors have discovered that the TDS level in the sump
increases and may exceed the predetermined TDS level and, thus,
causes the formation of cloudy ice.
[0011] Contrary to either of the prior art processes seeking to
reduce TDS levels as discussed above, the present inventors have
developed a unique method and system for formation of clear ice,
which does not have to dump water to maintain the TDS level. To the
contrary, the present disclosure monitors the conductivity level
(e.g., TDS level) during the freeze cycle and when the TDS level
exceed a predetermined level, the pump valve is energized so that
fresh water is introduced into the ice making machine during the
freeze cycle to ensure that the TDS level remains below the
predetermined level during a substantial portion of the freeze
cycle so that ice clear or substantially clear ice is produced.
This reduces the amount of water used and also produces
consistently clear ice during each freeze/harvest cycle, which is
not possible using the monitoring and discharge systems disclosed
in the prior art.
[0012] The present disclosure also provides many additional
advantages, which shall become apparent as described below.
SUMMARY
[0013] A method for making clear ice comprising: filling a water
sump to a predetermined level; contacting a refrigerant to an
evaporator; circulating water from the sump over the evaporator to
form ice on the evaporator; monitoring the water level in the sump;
and monitoring the conductivity of the water in the sump to
determine if the conductivity of the water is equal to or greater
than a predetermined conductivity valve, (i) if the conductivity is
not equal to or greater than the predetermined conductivity valve
and if the water level reaches a predetermined lower water level,
then complete the ice making cycle and initiate to the harvest
cycle; or (ii) if the conductivity is equal to or greater than the
predetermined conductivity valve and if the water level has not
reached a predetermined lower water level, then add additional
water to the water sump.
[0014] If the ice making cycle has ended and the conductivity of
the water in the sump is not equal to or greater than the
predetermined valve, adding additional water to the sump before
initiating another ice making cycle.
[0015] If the ice making cycle has ended and the conductivity of
the water in the sump is equal to or greater than the predetermined
conductivity valve, dumping the water in the sump and adding freeze
water to the sump before initiating another ice making cycle.
[0016] The step of monitoring the water level is via a water level
probe comprising a first probe for detecting a high water level and
second and third probes for detecting a low water level.
[0017] The water level probe measures the conductivity of the water
by determining the conductivity difference between the second and
third probes, wherein the third probe is a reference probe. The
predetermined conductivity value is about 30 GPH.
[0018] A system for producing clear ice, the system comprising: a
water supply; a water sump; an evaporator; a water inlet valve
disposed between the water supply and the water sump; a pump for
circulating water from the sump to the evaporate during an ice
making cycle; a controller that monitors the water level in the
sump and the conductivity of the water in the sump to determine if
the conductivity of the water is equal to or greater than a
predetermined conductivity valve, (i) if the conductivity is not
equal to or greater than the predetermined conductivity valve and
if the water level reaches a predetermined lower water level, then
complete the ice making cycle and initiate the harvest cycle; or
(ii) if the conductivity is equal to or greater than the
predetermined conductivity valve and if the water level has not
reached a predetermined lower water level, then add additional
water to the water sump.
[0019] Further objects, features and advantages of the present
disclosure will be understood by reference to the following
drawings and detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] FIG. 1 is a schematic representation of a water level probe
function of the present disclosure;
[0021] FIG. 2 is a block diagram of the water system flow according
to the present disclosure; and
[0022] FIG. 3 is logic diagram of the TDS sensing process and water
fill used to form clear ice according to the present
disclosure.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0023] A system for making ice while controlling the water inlet
and outlet based on the water conductivity in the sump trough. The
water inlet valve is energized to bring all of the water in at one
time prior to initiating the freeze cycle. Preferably, the amount
of water is sufficient make a single batch of ice through one
freeze and harvest cycle. And a conductivity measurement is made
and depending upon the measurement the water valve may be energized
again throughout the ice making or freezing cycle, as is necessary
to maintain the conductivity or TDS level at or below a
predetermined amount. During the freeze cycle, sensor readings are
periodically taken of the water in the sump to determine if
additional water needs to be added to reduce the TDS level, thereby
producing substantially clear ice.
[0024] The system measures TDS of the supply water in the sump as
water enters the system. If TDS is below the lower limit of normal,
then no more water is brought into the sump and ice is made with
that minimal amount of water. That is, the sump is initially filled
until water contacts the lower level sensor which allows
measurements of TDS. If the TDS measurement is between the lower
and upper limit of normal, then an additional quantity of water is
added to the sump by filling the sump until water contacts the
upper level sensor and ice is continued to be made with that total
water quantity. If TDS is above the upper limit of normal, then an
additional quantity of water is added to the sump by filling the
sump until water contacts the upper level sensor during the course
of the ice making cycle.
[0025] The present disclosures can best be described by referring
to the attached drawings, wherein FIG. 1 is block diagram of water
system 1 used in the system of the present disclosure. System 1
initiates the ice making process via control board 3 which sends
output signals via electrical conduits 5 and 7 to energize water
inlet valve 9 and de-energize water dump valve 11, respectively.
With water inlet valve 9 energized, water from water supply 13
passes through water inlet valve 9 via conduit 15 into water sump
trough 17 where it is pump via pump 19 into conduit 21 and
thereafter to water distributor 23. Water from water distributor 23
is then distributed over evaporator 25 where it is formed into ice.
Water that does not freeze onto evaporator 25 is then returned to
water sump trough 17 for recycling to water distributor 23.
[0026] A water level probe 27 is capable of measuring the water
level in water sump trough 17, as well as detecting the
conductivity of the water in water sump trough 17, so that the TDS
level of the water can be monitored by control board 3. FIG. 1
depicts water level probe 27, wherein probe `A` is disposed at the
level of water needed to for the ice making cycle to make a desired
quantity of ice. Probes `B` and `C` are both disposed at the low
level and measure conductivity of the water. As the water level
drops during the ice making cycle from level `A` where is
registered low TDS or low conductivity toward levels `B` and `C`,
then conductivity tends to increase. When the water's conductivity
reaches a predetermined level, i.e., an undesirable TDS level,
control board 3 opens water inlet valve 9 so that fresh or
additional water from water supply 13 passes through conduit 15
into water sump trough 17. This additional water is then pumped to
water distributor 23 via pump 19 and conduit 21 so that the ice
being formed on evaporator 25 remains substantially clear. If
additional water is not added when the conductivity or TDS level
reaches an undesirably high level, then the ice being formed would
tend to get cloudy which is not appealing to consumers. See Table 1
below:
TABLE-US-00001 TABLE 1 TDS/CONDUCTIVITY SCALE B/C READING FUNCTION
High (30-45 GPH) high If B/C probe readings are within this range,
fill conductivity (low to level A, when water drops to B/C refill
to A resistance) again for additional water and dump every cycle
Normal (15-29 GPH) If B/C level is within this range, fill to level
A and dump every cycle Low (0-14 GPH) low If B/C level is within
this range, fill to level A conductivity (high and do not dump
every cycle resistance)
[0027] FIG. 1 is a diagram showing the relative probe location. The
high level probe is identified as "A" in this figure and is used to
determine the high water level of the water sump. Probes "B" and
"C" are low water level probes and are used to identify the low
water sump level, as well as to measure the conductivity of the
water present in the sump.
[0028] FIG. 3 is a logic diagram that depicts the ice making method
of the present disclosure. The user will initiate the start of the
ice cycle 31. The system then check to see if ice cycle is
beginning 33. If the ice cycle does not begin, then the system
returns to 31. If the ice cycle does begin, then the conductivity
of the water in sump trough 17 is measured 35 by water level probe
27 and control board 3. Control board 3, then compares 37 measured
conductivity (M) to preset conductivities (H,N,L). Conductivity is
a measurement of a materials ability to conduct electricity. In
this present disclosure the water level probe is also measuring the
conductivity of the water in the water sump. The resistance between
the probes indicates the water's concentration of total dissolved
solids (TDS) and scale. The table in FIG. 1 describes the threshold
levels for low to high levels of TDS and scale. The controller
measures the conductivity of the water via probes "B" and "C" (FIG.
1) and compares the measurement to a stored value resident in the
controller.
[0029] Control board 3 will then determine if the measured
conductivity is equal or less than a preset or predetermined
conductivity valve L.ltoreq.Preset Value 39. If the conductivity is
low and value L.ltoreq.Preset Value then end ice formation 41 and
end of ice making cycle 43. This again refers to the block diagram
"end of ice formation" which is the completion of the ice freeze
cycle. If L is greater than the Preset Value, then the system
checks to see if measured conductivity (M) is NORMAL 45 (15-29
GPH), i.e., M=N. If conductivity is NORMAL, then end of ice
formation 47. If conductivity is not NORMAL, then the system
determines if the measured conductivity (M) is high 49, i.e.,
M.gtoreq.H preset valve. If the measured conductivity is not high,
then the system returns to compare measured M to preset (H,N,L) 37.
If the measured conductivity is high where M.gtoreq.H, then control
board 3 energize water inlet 9 such that additional or fresh water
is supplied to water sump trough 17 via water supply 13 during the
freeze cycle 51 and then ends the ice formation 47. End of ice
Formation 47 means that the machine operates until it is signaled
from the Ice Thickness Probe (ITP) at which point the machine
enters into harvest cycle and ultimately the completion of the
complete cycle. If the system has measured high conductivity, then
after the freeze cycle has been completed, control board 3
energizes the water dump valve 11, such that all of the water in
sump trough 17 is dumped at the end of the ice making cycle 53 and
then the freeze cycle is ended 43.
[0030] In normal operation, the Ice Thickness Probe (ITP)
determines when the machine is to enter into the harvest mode. When
the ice forms on the evaporator to a point where the individual
cubes are interconnected (bridged) the ice contacts the ITP and a
signal is sent to the control board which initiates harvest. That
is, the system continues its' normal freeze cycle and is terminated
when the Ice Thickness Probe (ITP) signals the controller.
[0031] While we have shown and described several embodiments in
accordance with our invention, it is to be clearly understood that
the same may be susceptible to numerous changes apparent to one
skilled in the art. Therefore, we do not wish to be limited to the
details shown and described but intend to show all changes and
modifications that come within the scope of the appended
claims.
* * * * *