WO2014117112A2

WO2014117112A2 - Ice maker with automatic clean and sanitize feature

Info

Publication number: WO2014117112A2
Application number: PCT/US2014/013250
Authority: WO
Inventors: Steven L. TRULASKE; John Broadbent
Original assignee: True Manufacturing Co., Inc.
Priority date: 2013-01-25
Filing date: 2014-01-27
Publication date: 2014-07-31
Also published as: WO2014117112A3

Abstract

A method of automatically controlling a clean and sanitize cycle for an ice maker includes the steps of filling a sump of the ice maker with clean supply water, adding a chemical to the sump, circulating this cleaning solution, and then purging the cleaning solution. Clean water is circulated next in order to rinse the ice marker. The sump is again filled with clean water and a sanitization chemical is dispensed to the sump to create a sanitization solution. The sanitization solution is circulated, purged and rinsed.

Description

ICE MAKER WITH AUTOMATIC CLEAN AND SANITIZE FEATURE

The present application claims priority to U.S. Provisional Patent Application No. 61756838 filed January 25, 2013, the contents of which are incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to automatic ice makers, and more particularly to ice makers with an automatic cleaning and sanitize feature.

BACKGROUND OF THE INVENTION

Sanitizing an ice machine on a regular basis is a recommended practice.

Sanitizing eliminates harmful bacteria, viruses and protozoa that thrive in a cold ice-making environment. It is important to keep in mind that much ice is either consumed as a food in beverages, comes in direct contact with food, and comes into direct contact with beverage containers that in turn directly contact a drinker's lips and mouth and the beverage. Therefore, ice is a food product, and an ice machine is a food preparing machine.

Sanitizing an ice maker is an important task that should not be neglected.

Various types of food-grade sanitizing agents can be used to kill bacteria and other biologies that may be attracted to ice makers.

These microscopic organisms can be either airborne or waterborne.

Municipal water systems are relatively free of harmful waterborne organisms due to chlorine treatment. Water filtration can also provide protection against waterborne bacterial contamination. However, airborne organisms can still migrate to the ice maker. Bacteria, viruses, and protozoa can also adhere to moist areas on the inside of the ice maker evaporator compartment and thrive in the cool, damp conditions. The result may be a mold, algae and slime buildup. Some of these bacteria and viruses can make people ill. Slime is usually a jellylike substance that is made up of algae, mold, and yeast spores that can become either airborne or waterborne.

A different process from "sanitizing" an ice machine is "cleaning" an ice machine. Cleaning an ice machine removes minerals and metals that build up in the water circuit of the ice machine and most particularly the sump used to catch and hold cooling water that falls from the ice maker's freeze plate. Minerals and metals generally comprise sodium, potassium, calcium, magnesium, iron, copper, manganese, phosphorus, and zinc in amounts that vary with locale and type of water source.

As the ice maker begins to form ice on the freeze plate, minerals and metals tend to build up concentration in the sump and begin to "wash out", or fall out of solution, to form a solid build-up in the lowest portion of the water circuit, the sump. This is because pure water tends to freeze first. This causes the mineral and metal concentration in the unfrozen water to increase as purer liquid water is removed in the form of ice.

This phenomenon is also evident when standing water freezes into an ice cube. The clearest water will tend to be at the outer edges of the cube, which freeze first, and a cloud of minerals eventually becomes trapped at the center of the cube.

No matter what method is used to form ice, a cleaner ice machine and purer water will form harder, more sanitary and clearer ice. Many ice makers include built-in flushing and purging cycles that direct sump water to a drain when a predetermined amount of water has been turned to ice. This flushing of high mineral concentration water out of the sump works to help minimize mineral formation in the sump, but eventually minerals will still form in the sump and elsewhere in the water circuit. Eventually, the minerals must still be cleaned to keep the ice clear and conditions sanitary.

When cleaning mineral buildup, or scale, from an ice machine, food grade acids are used to help dissolve the mineral buildup. Heavier scale deposits may require soaking in the acid solution. Manual scrubbing, scraping or wiping is also effective and sometimes necessary to clean minerals and metals from the sump.

Generally cleaning and sanitizing cannot be done at the same time because the chemicals used for each are not compatible and their combination can generate noxious and dangerous gases.

Also, because cleaning and sanitizing is time consuming, one or both are sometimes neglected. Cleaning and sanitizing requires the ice maker to be taken offline for a period of time and is therefore inconvenient. There is a need in the art for an ice machine that simplifies and automates the process of sanitizing and cleaning the ice machine such that both process can be run unattended. Other attempts at automatically cleaning and sanitizing have been tried but have not been successful. U.S. Patent No. 5,408,834 to Schlosser describes a mechanism that automatically injects fluid into an ice machine during a either a cleaning or sanitization process. Unfortunately, Schlosser only addresses injecting a single liquid into the ice maker, so it cannot both clean and sanitize an ice maker because, as discussed above, the chemicals for cleaning and sanitizing are not compatible and must be separately dispensed and cycled through the ice maker. As such, Schlosser fails to solve the problem of both cleaning and sanitizing.

U.S. Patent No. 6,619,051 to Kilawee describes combining two incompatible acids to clean and sanitize and then using the offgassing created by their mixture for gaseous sanitizing of the icemaker's headspace. However, as Kilawee acknowledges, the cleaning and sanitizing acids are incompatible and create either chlorine gas or chlorine dioxide gas. Since chlorine gas and chlorine dioxide gas are toxic and potentially explosive, Kilawee fails to effective address the problem of safely incorporating an automatic sanitize and clean cycle in an ice maker.

SUMMARY OF THE INVENTION

DESCRIPTION OF THE DRAWING

FIG. 1 is a flow chart depicting a method of operating an ice maker with an automatic clean and sanitize feature. DESCRIPTION OF THE PREFERRED EMBODIMENT

While this invention is susceptible of embodiment in many different forms, there is shown in the drawings and will herein be described in detail a preferred embodiment of the invention with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the broad aspect of the invention to the embodiment illustrated.

The ice machine incorporating the automatic clean and sanitize feature of the present invention is a typical commercial-type ice making machine system consisting of a lower housing that forms an ice bin that is accessible through a door and a separate upper ice making machine comprising a refrigeration compartment housing the compressor and condenser units of a closed refrigeration circuit. The ice making machine further includes an evaporator unit attached to an ice making grid or freeze plate, which is located above a water pump and sump. The various compartments of the ice maker cabinet are closed by suitable fixed and removable panels to provide temperature integrity and compartmental access, as will be understood by those in the art.

The closed refrigeration system housed in the ice maker includes the refrigeration compressor and the air-cooled condenser. The high pressure discharge side of the compressor is connected by a discharge line to the condenser. Saturated liquid refrigerant flows from the condenser through liquid line having a filter/drier unit therein and is connected to a typical thermostatic expansion valve which meters refrigerant into the inlet of the evaporator unit in the freeze compartment. The outlet of the evaporator is connected by a suction line to a suction side of the compressor. The refrigeration cycle is typical— the compressor supplies high pressure hot refrigerant gas to the condenser, where it is cooled to its saturation temperature and liquefied refrigerant flows to the evaporator through the expansion valve. The expanding vaporization of liquid refrigerant in the evaporator removes heat from the water on the evaporator and freeze plate thereby forming the ice cubes in the lattice molds thereon, and the gaseous refrigerant is returned to the compressor suction side to complete the refrigeration and freeze cycle.

The system also includes a hot gas by-pass line connected between the discharge line and the evaporator inlet side downstream of expansion valve, and being controlled by solenoid valve to initiate an ice harvest cycle. When this solenoid valve is energized, the hot gas bypass line warms the freeze plate to thaw ice cubes that have been formed thereon. The result is that the ice cubes melt away from the freeze plate and fall through an ice hole into the lower housing from where it can be retrieved and used.

Referring to FIG. 1, in order to activate the clean and sanitize feature of the present invention, a user first presses a button that signals an ice machine controller to begin the clean and sanitize program in step 10. Preferably, the controller is an electronic control, but may also comprise a mechanical or electromechanical controller. In the next step 12, the controller initiates a harvest cycle to remove any ice that has accumulated on the freeze plate.

After the harvest cycle is complete, and the freeze plate is substantially free from ice, in step 14 the controller signals a water supply valve to open to provide water to fill the sump located directly below the freeze plate. A level sense detects when the sump is sufficiently full and signals the controller to close the water supply valve. Next in step 16, the controller signals a user to add a cleaning chemical to the sump water for the "clean" portion of the clean and sanitize process. Alternatively, the controller could optionally signal a valve or a pump to dispense cleaning chemical into the sump for the cleaning process.

In step 18, the controller next waits a sufficient amount of time for the user to add the cleaning chemical and proceeds to step 20. Alternatively, the controller could wait for the user to press a button signaling to the controller that the chemical has been added.

Next, in step 20, the controller signals a pump to begin circulating the water containing the cleaning chemical from the sump to a reservoir at the top of the freeze plate where the cleaning water then begins to cascade down the freeze plates. This cycle continues for the desired amount of time, for example 60 seconds, before proceeding to step 22. During this cycle, mineral and metal deposits are cleaned from the water circuit, including the circulating pump, sump, the upper reservoir, the freeze plate and the water circuit's tubing.

In step 22, the controller begins to purge the cleaning solution from the sump by pumping it to a drain. The purge cycle continues for sufficient number of seconds in order to pump the entire contents of the sump to the drain. In the next step 24, the controller again opens a water supply valve to refill the sump with water from the water supply and in step 26 the controller decides whether previous steps 20, 22 and 24 have been performed a predetermined number of times. If not, steps 20, 22 and 24 will be re-performed. Note that subsequent passes through step 20 only circulate clean water, not chemicals. Thus these subsequent steps act as rinse cycles. Once the sufficient number of cycles have been completed, the rinsing sequence and the cleaning portion of the cycle is complete. The controller will then move on to step 28.

At this point or in time or earlier, the user will have loaded a tablet dispensing device with a sanitizing tablet. The tablet dispensing device can be any device suitable for dropping a tablet such as container with a solenoid operated trap door or auger for pushes a tablet off of the edge of a surface.

After the cleaning and sanitizing operation has been initiated and the cleaning solution and the sanitizing tablets have been added, human interaction is no longer necessary and the user may leave the ice maker unattended to complete the clean and sanitize process automatically. In step 28, the controller signals the tablet dispensing device to dispense a sanitizing tablet into the sump, which was filled with water in a previous step 24. The sanitizing tablet will now immediately begin to dissolve in the sump water.

The controller once again signals the pump to begin circulating the water containing the chemical from the dissolved sanitizing tablet from the sump to the reservoir at the top of the freeze plates in step 30. The sanitizing water then begins to cascade down the freeze plates. This cycle continues for a desirable number of seconds, for example 60 seconds, before proceeding to step 32. During this cycle, bacteria, virus, and other undesireable biologies within the water circuit are destroyed by the sanitizing chemical, including the circulating pump, sump, the upper reservoir, the freeze plate and the water circuit's tubing.

In step 32, the controller signals the pump to again purge the water from the sump to the drain. Once the water has been purged from the sump to the drain, the controller refills the sump in step 34. Next a determination of whether the previous steps 30, 32 and 34 have been performed a predetermined number of times. If not, steps 30, 32 and 34 are re-performed. As before, the subsequent passes through steps 30, 32 and 34 serve to rinse the chemicals out of the ice machine. Once the sufficient number of cycles and the rinsing has been completed, the controller will move on to step 38. In step 38, the controller ends the clean and sanitize program and restarts the normal ice making program to resume the production of ice in the ice maker.

The above example shows that the invention, as will be defined by the claims, has far ranging application and should not be limited merely to the embodiment shown and described in detail. Instead the invention should be limited only to the words of the claims. Aspects of the preferred embodiment not claimed are not intended to be part of the claimed invention.

Claims

We claim:

1. A method of automatically controlling a clean and sanitize cycle for an ice maker comprising the steps of:

accepting a user input to initiate an automatic clean and sanitize cycle; filling a sump of the ice maker with clean supply water;

adding a cleaning chemical to the clean supply water located in the sump to create a cleaning solution;

circulating the cleaning solution to a reservoir at a top of a freeze plate that allows the cleaning solution to cascade down the freeze plate and back to the sump;

purging the cleaning solution from the sump;

filling the sump with clean water, circulating the clean water to the reservoir at the top of a freeze plate that allows the clean water to cascade down the freeze plate, and purging the clean water;

filling the sump with clean water and automatically dispensing a sanitization chemical into the sump of the ice marker to create a sanitization solution;

circulating the sanitization solution to the reservoir at the top of the freeze plate that allows the sanitization solution to cascade down the freeze plate and back to the sump;

filling the sump with clean water, circulating the clean water to the reservoir at the top of the freeze plate that allows the cleaning solution to cascade down the freeze plate, and purging the clean water; and reinitiating an ice making process.

2. The method of claim 1 further comprising the step of initiating a harvest cycle to harvest ice from the freeze plate before performing the steps of claim 1.

3. The method of claim 1 further comprising the step of automatically sensing the level of water within the sump to determine the level of water within the sump and to stop a supply of water to the sump.

4. The method of claim 1 where the step of adding a cleaning chemical to the clean supply water located in the sump to create a cleaning solution comprises the step of signaling a user to add the cleaning chemical to the sump water.

5. The method of claim 1 where the step of adding a cleaning chemical to the clean supply water located in the sump to create a cleaning solution comprises the step of automatically dispensing a cleaning chemical into the sump.

6. The method of claim 1 where the step of adding a cleaning chemical to the clean supply water located in the sump to create a cleaning solution further comprises the step of waiting a predetermined amount of time for a user to add the cleaning chemical to the sump.

7. The method of claim 1 where the step of adding a cleaning chemical to the clean supply water located in the sump to create a cleaning solution further comprises the step of receiving an input from a user that the cleaning chemical has been added to the sump.

8. A method of automatically controlling a clean and sanitize cycle for an ice maker comprising the steps of:

circulating the cleaning solution to a reservoir at a top of a freeze plate that allows the cleaning solution to cascade down the freeze plate;

purging the cleaning solution from the sump;

rinsing the sump and the freeze plate a predetermined number of times; filling the sump with clean water and automatically dispensing a sanitization chemical into the sump of the ice maker to create a sanitization solution;

circulating the sanitization solution to the reservoir at the top of the freeze plate that allows the sanitization solution to cascade down the freeze plate; and automatically rinsing the sump and the freeze plate a predetermined number of times.

9. The method of claim 8 further comprising the step of initiating a harvest cycle to harvest ice from the freeze plate before performing the steps of claim 1.

10. The method of claim 8 further comprising the step of automatically sensing the level of water within the sump to determine the level of water within the sump and close a valve supplying clean water to the sump.

11. The method of claim 8 where the step of adding a cleaning chemical to the clean supply water located in the sump to create a cleaning solution comprises the step of signaling a user to add a cleaning chemical to the sump water.

12. The method of claim 8 where the step of adding a cleaning chemical to the clean supply water located in the sump to create a cleaning solution comprises the step of automatically dispensing a cleaning chemical into the sump.

13. The method of claim 8 where the step of adding a cleaning chemical to the clean supply water located in the sump to create a cleaning solution further comprises the step of waiting a predetermined amount of time for a user to add the cleaning chemical to the sump.

14. The method of claim 8 where the step of adding a cleaning chemical to the clean supply water located in the sump to create a cleaning solution further comprises the step of receiving an input from a user that the cleaning solution has been added to the sump.