Method and system for controlling the initiation of a freeze cycle pre-set time in an ice maker

Abstract

A novel control logic for an individual cube spray type ice machine. The duration of the freeze cycle is able to adapt to changes in inlet water temperature, changes in ambient air temperature, and the impact of warm temperatures of internal ice making parts within the ice machine due to off cycle periods. This is accomplished through a combination of starting a freeze time period only after the water temperature for the volume of water circulating over the evaporator has reached approximately 32° F., and a freeze time period value that is a function of the refrigerant temperature leaving the condenser at the time where the water reaches approximately 32° F.

What is claimed is: 
     
         1 . An ice making machine comprising:
 a heat exchange system comprising an evaporator and a condenser configured to make ice pieces with water applied to said evaporator during a freeze cycle; and   a controller that controls a start time and an end time of the freeze cycle, wherein the start time begins only if a temperature of said water is 32 degrees F. or lower and the end time is based on a temperature of refrigerant exiting said condenser when the start time begins.   
     
     
         2 . The ice making machine of  claim 1 , wherein the end time is determined from a table of time versus condenser refrigerant exit temperatures at a time when the water is approximately 32 degrees F. 
     
     
         3 . The ice making machine of  claim 1 , wherein said heat exchanger system further comprises one or more sprayers that spray the water on the evaporator. 
     
     
         4 . The ice making machine of  claim 1 , further comprising a first temperature sensor located in the water and a second temperature sensor located to sense the temperature of the refrigerant exiting the condenser, and wherein the start and end times are determined based on temperatures sensed by the first and second temperature sensors. 
     
     
         5 . The ice making machine of  claim 1 , further comprising a processor and program module associated with the controller, wherein the processor executes instructions of the program module to determine the start time and the end time of the freeze cycle. 
     
     
         6 . A method of controlling ice making of an ice making machine comprising:
 configuring an evaporator and a condenser to make ice pieces with water applied to said evaporator during a freeze cycle;   controlling a start time of the freeze cycle to begin only if a temperature of said water is 32 degrees F. or lower; and   controlling an end time of the freeze cycle based on a temperature of refrigerant exiting said condenser when the start time begins.   
     
     
         7 . The method of  claim 6 , further comprising:
 determining the end time from a table of time versus condenser refrigerant exit temperatures at a time when the water is approximately 32 degrees F.   
     
     
         8 . The method of  claim 6 , further comprising:
 locating a first temperature sensor to sense a temperature of the water;   locating a second temperature sensor to sense a temperature of refrigerant exiting the condenser, and wherein the start and end times are determined based on the temperatures sensed by the first and second temperature sensors.   
     
     
         9 . The method of  claim 6 , further comprising:
 executing instructions of a program module to determine the start time and end time of the freeze cycle.   
     
     
         10 . The method of  claim 6 , further comprising:
 spraying the water on the evaporator.