US20120031126A1

US20120031126A1 - Control system for an ice maker

Info

Publication number: US20120031126A1
Application number: US13/197,607
Authority: US
Inventors: Lei Andrew Zhang; Yong Terry Wang
Original assignee: Manitowoc Foodservice Companies LLC
Current assignee: Welbilt Foodservice Companies LLC
Priority date: 2010-08-06
Filing date: 2011-08-03
Publication date: 2012-02-09
Also published as: CN103429976A; BR112013002192A2; WO2012018935A1; EP2601461A1

Abstract

A system for ice making includes a controller, a compressor, a condenser, an evaporator, a water sump, a curtain disposed adjacent to the evaporator, a water distributor in communication with the water sump to draw water from the water sump and distribute the water over the evaporator during an ice making cycle, a water level sensor disposed in the water sump. The water sensor detects a high water level and signals the controller to initiate an ice making cycle, the sensor further detects a low water level in the sump and signals the controller to terminate the ice making cycle and initiates a harvest cycle. The system further includes a curtain sensor disposed about the curtain that detects when a harvest cycle has ended and sends a signal to a controller to fill the sump with water.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application Ser. No. 61/371,575, filed Aug. 6, 2010, the contents of which are incorporated by reference herein.

BACKGROUND

1. Field of the Disclosure
The present disclosure relates to a control system for an ice maker. More particularly, the present disclosure relates a control system for an ice maker that only requires a water level sensor and a curtain sensor.
2. Description of Related Art
Conventional ice makers in market today may use a large number of sensors for determining and monitoring various factors of an ice maker. This can include, amongst other things, the use of an ice probe sensor to directly sense the ice thickness, and an air temperature sensor along with a water temperature sensor to calculate the freeze time and harvest time.
However the use of a large number of sensors often cannot accurately and efficiently determine these factors, such as ice capacity and the calculation of cycle times within a single ice maker. In addition, this may lead to a higher costing product having complex data collecting systems and increased component failure.
Thus, there is a need for an ice maker having a control system with a minimal number of sensors, resulting in a simple and low cost system. In addition, resulting in improved efficiency and providing low water waste.

SUMMARY

The present disclosure provides for a control system for an ice maker including a water level sensor and a curtain sensor for providing simple, low cost and efficient ice production. In particular, the water level sensor initiates/terminates the freeze cycle and initiates the harvest cycle and the curtain sensor terminates the harvest cycle. Furthermore, the ice maker provides for low water usage and adjustability of the ice thickness by the user.
The present disclosure provides a system for ice making. The system for ice making includes a controller, a compressor, a condenser, an evaporator, a water sump, a curtain disposed adjacent to the evaporator, a water distributor in communication with the water sump to draw water from the water sump and distribute the water over the evaporator during an ice making cycle, a water level sensor disposed in the water sump. The water sensor detects a high water level and signals the controller to initiate an ice making cycle, the sensor further detects a low water level in the sump and signals the controller to terminate the ice making cycle and initiates a harvest cycle. The system further includes a curtain sensor disposed about the curtain that detects when a harvest cycle has ended and sends a signal to a controller to fill the sump with water.
The present disclosure also provides a method for ice making. The method includes filling a water sump with water, the water having a water level, the filling moves a water level indicator toward a first position according to the water level, draining the water from the water sump after the water level indicator achieves the first position, the draining moves the water level indicator to a second position according to the water level. The method further includes filling the water sump with the water, the filling continues until the water level indicator achieves the first position. In addition, the method includes freezing the water thereby creating ice; and harvesting the ice by dropping the ice from an evaporator into a container, the container has a curtain sensor that is activated by ice impact when the ice drops from the evaporator into the container.

BRIEF DESCRIPTION OF THE DRAWINGS

Other and further benefits, advantages and features of the present invention 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:

FIG. 1 is a diagram of a refrigerant system

FIG. 2 is a front view of an ice maker of the present disclosure.

FIG. 3 is front view of the ice maker shown in FIG. 1, with a water sump removed.

FIG. 4 is a front view of the ice maker shown in FIG. 1, with the curtain removed.

FIG. 5 is a rear view of the icemaker shown in FIG. 1.

FIG. 6 is a rear view of the ice maker shown in FIG. 1, with an air condenser removed.

FIG. 7 is the same view shown in FIG. 6, with a fan motor removed.

FIG. 8 a is a water level sensor of the present disclosure.

FIG. 8 b is an internal circuit of the water level sensor of FIG. 8 a.

FIG. 9 is flow chart illustrating a control system for an ice maker of the present disclosure.

DETAILED DESCRIPTION OF THE DISCLOSURE

Referring to FIG. 1, a refrigeration system 11 for cooling a fluid (e.g., air or water) is shown. System 11 includes a condenser 41, an evaporator 16, an expansion device 45, and a compressor 40 in fluid communication with one another.
Compressor 40 is operative to circulate a refrigerant between condenser 41 and evaporator 16 and to compress the vapor refrigerant before it enters condenser 41.
Condenser 41, which in the illustrated embodiment is in heat exchange relationship with outdoor ambient air, and is operative to substantially condense the vapor refrigerant. Evaporator 16, which is in heat exchange relationship with the indoor air to be cooled, is operative to substantially evaporate the refrigerant.
Expansion device 45 facilitates evaporation of the refrigerant by reducing the pressure thereof before the refrigerant enters evaporator 16. The heat absorbed by the refrigerant during evaporation cools the air passing through evaporator 16. The cooled air is supplied to an indoor conditioned space via an air supply duct (not shown).
In addition to the primary components of system 11 described hereinabove, condenser 41 has a fan 46 operatively associated therewith. Fan 46 moves air (typically outdoor ambient air) across condenser 41 to cool the refrigerant in condenser 41 and facilitate condensation thereof. Similarly, evaporator 16 has a fan (not shown) operatively associated therewith for moving indoor air to be cooled across evaporator 16.
Referring to FIGS. 2-7, there is shown an ice maker 10 according to the present disclosure.
FIG. 2 is a front view of an ice maker 10 having a curtain 15 with a curtain sensor 17, a water sump 20 and a control system 25.
FIG. 3 is a front view of the ice maker 10 with a water sump 15 removed from ice maker 10 to show a water pump 30 and a water level sensor 35.
FIG. 4 is a front view of the ice maker 10 with the curtain 15 removed to show an evaporator 16, a dump valve, and a water inlet valve 43.
FIG. 5 is a rear view of ice maker 10 showing an air condenser 41, a compressor 40 and water valve 43.
FIG. 6 is a rear view of the ice maker 10, with an air condenser removed to show a hot gas valve 42 and a fan motor 46.
FIG. 7 illustrates the same view of ice maker 10 shown in FIG. 6, with fan motor 46 removed to show an expansion valve 45.
FIG. 8 a shows water level sensor 35 having a water level 36. Water level 36 can be any type of water level, including but not limited to, a magnetic float ball.
FIG. 8 b shows the internal circuit of water level sensor 35 having a first sensor position 37 (S1) and a second sensor position 39 (S2) to provide and receive signals with control system 25. Water level sensor 35 can be any type of sensor, including a ring type magnet disposed within a float ball. Water level sensor 25 triggers a reed switch from on/off depending on the water level, i.e., the volume of water in water sump 20.
Ice maker 10 with control system 25 is a low cost, simple system containing only 2 sensors. Ice maker 10 preferably has a water level sensor and a curtain sensor, compared to a large number of sensors contained in conventional ice makers. In addition, ice maker 10 does not require a water temperature sensor, liquid line thermistor or discharge line thermistor. Thus, ice maker 10 has a simpler design, as a result providing lower fail rates for components and a lower cost to the consumer. Ice maker 10 further provides low water usage and prevents overfill, thus is more efficient.
Typically, ice maker 10 has a toggle switch 5 with three positions: ICE, OFF and CLEAN. In addition, ice maker 10 may have LED lights to indicate status and/or alert issues that may arise. Furthermore, ice maker 10 may include a notification system, such as a buzzer, for indication when a fault or problem occurs.
FIG. 9 provides a flow chart, i.e., flow chart 900, which illustrates operation of ice maker 10 controlled by control system 25 according to the present disclosure.
In particular, FIG. 9 illustrates five (5) processes carried out by ice maker 10 under the control of control of control system 25. The 5 processes include, but are not limited to: (i) initial water fill and purge, (ii) water fill and refrigerant start and pre-chill, (iii) freeze cycle, (iv) harvest cycle, and (v) automatic shut down sequence.

Initial Water Fill and Purge

The (i) initial water fill and purge process provides a user with a cleaner and more sanitary ice maker 10. Flow chart 900 begins with “initial start”, when toggle switch 5 is moved to “ICE” position to activate ice maker 10. See FIG. 1, Toggle Switch 5.
At step 405, control system 25 checks the status of sensor position (S1) 37 of water level indicator 35.
If sensor position (S1) 37 is determined to be in the opened position, flow chart 400 progresses to step 410. If sensor position (S1) is determined to be in the closed position, flow chart 400 progresses to step 415.
At step 410, a water inlet valve (WTV) receives a signal to activate and to fill ice maker 10 with water. When ice maker 10 is filled with water, water level indicator 35 eventually keeps sensor position (S1) 37 in the closed position for two (2) seconds. Thereafter, the water inlet valve 43 receives a signal to deactivate and to stop the flow of water. Flow chart 400 then returns to step 405.
At step 415, ice machine 10 receives a signal to begin a dump procedure with the water pump and water dump energized while the water intake valve is de-energized.
Step 417 monitors sensor position (S2) 39 to determine if it is open or closed during the dump procedure of step 415. If S2 is open, flow diagram 400 is returned to step 415. Once sensor position (S2) 39 is closed by water level indicator 36 flow diagram progresses to step 420.
At step 420, sensor position (S2) 39 is closed for two (2) seconds. Thereafter, the water pump and dump valve receive a signal to activate and to fill ice maker 10 with water.
Thus, ice machine 10 prepares for refrigeration and a pre-chill phase. In addition, a water pump valve, i.e., water pump valve 30 of FIG. 2, receives a signal to activate and to drain the water, preferably at one second intervals.

Water Fill and Refrigerant Start and Pre-Chill

As shown in FIG. 4, after the water purge or water dump phase described above, flow chart 400 transitions into (ii) water fill and refrigerant start and pre-chill process. The (ii) water fill and refrigerant start and pre-chill process cools down the machine first which, in turn, shortens a subsequent freeze time, thereby providing for an increased efficiency for refrigeration.
The transition from the (i) to (ii) occurs at step 420.
At step 420, the water inlet valve (WTV) 43 and a hot gas valve 42 are energized and the water pump and water dump valve 44 are de-energized. When flow chart 900 performs step 420, steps 425, 435,440, 445 and 450 are run. While these steps are performed, steps 430 is run in parallel with step 433 performed after step 433 is performed. All of these steps are discussed below.
At step 420, the hot gas valve (HGV) and the water inlet valve (WTV) receive a signal to activate at one second intervals.
Step 425 provides a wait period of 45 seconds for refrigerant system balance. After 45 seconds elapses, flow chart 400 progresses to step 435.
At step 435, a contactor, located in control box 25, receives a signal to activate, and for refrigeration to begin. After step 435, flow chart 400 progresses to step 440.
Step 440 provides a wait period for 5 seconds for refrigerant system hot balance. After the wait period of 5 seconds, flow chart 400 progresses to step 445.
At step 445, the HGV is de-energized. That is, the hot gas valve receives a signal to deactivate and to shut down. This causes ice machine 10 to enter into a pre-chill phase. After step 445, flow chart 400 progresses to step 450.
Step 450 provides a 30 second wait period is provided to cool and pre-chill the ice maker 10, before entering the (iii) freeze cycle process described below.
During performance of steps 425, 435,440, 445 and 450, flow diagram 900 also evaluates if the water inlet valve is de-energized in step 433. In particular, when the water level in ice maker 10 increases to keep sensor position (S1) 37 closed for 2 seconds, the water inlet valve receives a signal to deactivate and to stop the flow of water into ice maker 10. Thereafter, flow diagram 900 progresses to step 450 to determine if the pre-chill phase continues for at least 30 seconds. If step 450 is valid, i.e., Y, the water pump is activated and ice machine 10 receives a signal to enter into a freeze cycle.

Freeze Cycle

During the (iii) freeze cycle, illustrated in steps 455 and 460, ice formation increases as the water level reduces to keep second sensor position (S2) 39 open. The water level reduces as water becomes ice in the water trough. After 2 seconds, ice machine 10 remains in the freeze cycle for 2 minutes. Thereafter, at 2 seconds from the end point of the freeze cycle, a controller in control system 25, reads a freeze time adjustment setting and, based on this setting, the controller signals ice machine 10 to either extend or shorten the 2 minute freeze cycle. Furthermore, the 2 minute timing of the freezing cycle is adjustable for preferred ice thickness of a user. Thereafter, ice machine 10 enters the (iv) harvest cycle starting at step 465 described-below.

Harvest Cycle

At step 465, ice machine 10 enters the harvest cycle. At step 465, the HGV, water pump valve and water dump valve become energized or activated. That is, the HGV, water pump valve, and the water dump valve receive a signal to activate and to harvest the ice and drain the water.
Preferably, the HGV, water pump valve and the water dump valve harvest the ice and drain the water at one second intervals, i.e., step 470.
At step 475, after harvesting the ice in step 470, the water pump and the water dump valves receive a signal to deactivate and to shut down, while the water inlet valve receives a signal to activate and to fill ice maker 10 with water in preparation for the next freeze cycle. Draining and re-filling the water during the harvest cycle provides for a cleaner and more sanitary ice maker 10.
Next, in step 480, the formed ice drops from the evaporator 16 and engages curtain sensor 17. During this step, ice machine 10 receives a signal to end the harvest cycle and deactive the hot gas valve. Then, ice machine 10 enters a pre-chill phase for the next freeze cycle.
In step 485, ice full, ice maker 10 initiates another pre-chill phase. In particular, when the ice is harvested, it is pushed out onto water curtain 15, which opens curtain sensor 17. If curtain sensor 17 is opened and then and closes before 7 seconds have elapsed, a signal is sent to initiate another pre-chill phase. If curtain sensor 17 remains opened for more than 7 seconds, then the controller receives a signal to initiate an automatic shut down. If ice machine 10 enters a harvest cycle with curtain sensor 17 open, the harvesting occurs for a maximum of 3.5 minutes.

Automatic Shut Down Sequence

In parallel to the harvest cycle, discussed above, steps 480 and 485 also perform an automatic shut down sequence.
Once curtain sensor 17 is opened for more than 7 seconds during a harvest cycle, ice machine 10 receives a signal to go into automatic shutdown. Ice machine 10 receives a signal to restart the initial water fill and purge and/or prechill once curtain sensor 17 closes again.
However, ice machine 10 remains off for at least 3 minutes before it can automatically restart, the 3 minutes begin at the time of automatic shutdown. Ice machine 10 can restart after the at least 3 minutes has elapsed and curtain sensor 17 recloses. If curtain sensor 17 closes prior to the at least 3 minutes has elapsed, ice machine 10 restarts as soon as the 3 minutes have elapsed. Ice machine 10 restarts by following the initial start-up sequence.

Claims

1. A system for ice making comprising:

a controller;

a compressor;

a condenser;

an evaporator;

a water sump;

a curtain disposed adjacent to said evaporator;

a water distributor in communication with said water sump to draw water from said water sump and distribute said water over said evaporator during an ice making cycle;

at least one water level sensor disposed in said water sump, said water sensor detects a high water level and signals said controller to initiate an ice making cycle, said sensor further detects a low water level in said sump and signals said controller to terminate said ice making cycle and initiates a harvest cycle; and

a curtain sensor disposed about said curtain that detects when a harvest cycle has ended and sends a signal to a controller to fill said sump with water.

2. The system of claim 2, wherein said water level sensor has a first water level position and a second water level position, wherein said first water level position detects said high water level and signals said controller to initiate an ice making cycle, and wherein said second water level position detects said low water level and signals said controller to terminate said ice making cycle and initiates a harvest cycle.

3. The system of claim 1, wherein said curtain sensor detects when said harvest cycle has ended by detecting a cessation of ice impacting said curtain.

4. The system of claim 3, wherein said curtain sensor is reed switch that detects if said curtain is open when said ice impacts said curtain or closed when ice does not impact said curtain thereby allowing said curtain to remain in a closed position.

5. The system of claim 1, wherein said water level sensor is a magnetic float ball.

6. The system of claim 5, wherein said magnetic float ball comprises a reed switch.

7. The system of claim 2, wherein said water sump is filled with water and drained from water and filled with water again, prior to said freeze cycle.

8. A method for ice making comprising:

filling a water sump with water, said water having a water level, said filling moves a water level indicator toward a first position according to said water level;

draining the water from the water sump after said water level indicator achieves said first position, said draining moves said water level indicator to a second position according to said water level;

filling said water sump with said water, said filling continues until said water level indicator achieves said first position;

freezing said water thereby creating ice; and

harvesting said ice by dropping said ice from an evaporator into a container, said container has a curtain sensor that is activated by ice impact when said ice drops from said evaporator into said container.

9. The method of claim 8, further comprising:

terminating said harvesting due to activation of said curtain sensor.

10. The method of claim 8, further comprising:

terminating said harvesting when said container is full.

11. The method of claim 8, wherein said water level indicator has at least one sensor.

12. The method of claim 8, wherein said water level indicator is a magnetic float ball.

13. The method of claim 12, wherein said magnetic float ball comprises a reed switch that detects said water level.

14. The method of claim 8, wherein said water level indicator has at least one sensor that detects said first position and said second position.

15. The method of claim 14, wherein said water level indicator has a first sensor that detects said first position and a second water sensor that detects said second position.