System and method for cryogenic enhancement to mechanical freezers

Abstract

A cryogenic enhanced mechanical freezer system and method are provided. The disclosed system includes a mechanical freezer compartment adapted for freezing food products, a cryogen injection system adapted to directly inject cryogen into the mechanical freezer compartment, an exhaust system adapted to rapidly evacuate cryogen vapors from the freezer compartment; and a freezer control system adapted to operatively control the exhaust system and cryogen injection system in response to selected inputs. The selected inputs may include user inputs as well as inputs received from a temperature sensor disposed in the freezer compartment and a gas analyzer adapted to monitor concentrations of selected gases within the freezer compartment. Access to the freezer compartment is prevented during cryogen injection and when the atmosphere in the freezer compartment is not safe as determined by the gas analyzer.

1 . A cryogenic enhanced mechanical freezer system comprising:
 a mechanical freezer compartment adapted for freezing food products;   a cryogen injection system adapted to directly inject cryogen into the mechanical freezer compartment;   a temperature sensor disposed in the freezer compartment and adapted to ascertain the temperature within the freezer compartment;   a gas analyzer disposed in operative association with the freezer compartment and adapted to monitor concentrations of selected gases within the freezer compartment;   an exhaust system in communication with the freezer compartment and adapted to rapidly evacuate cryogen vapors from the freezer compartment   a freezer control system adapted to control the exhaust system and cryogen injection system in response to selected inputs including inputs received from temperature sensor and gas analyzer.   
   
   
       2 . The system of  claim 1  wherein the exhaust system further comprises a first exhaust adapted to remove cryogen vapors injected into the freezer compartment when the cryogen injection system is active and an auxiliary exhaust adapted to rapidly evacuate cryogen vapors from the freezer compartment when the cryogen injection system is inactive. 
   
   
       3 . The system of  claim 1  further comprising a cryogen source in flow communication with the cryogen injection system wherein the cryogen is carbon dioxide and the gas analyzer monitor concentrations of carbon dioxide within the freezer compartment. 
   
   
       4 . The system of  claim 1  further comprising a cryogen source in flow communication with the cryogen injection system wherein the cryogen is nitrogen and the gas analyzer monitor concentrations of oxygen within the freezer compartment. 
   
   
       5 . The system of  claim 1  further comprising freezer compartment interlocks adapted to prevent access into the freezer compartment when the cryogen injection system is active. 
   
   
       6 . The system of  claim 1  further comprising freezer compartment interlocks coupled to the freezer control system, the freezer compartment interlocks adapted to prevent access into the freezer compartment in response to inputs from the gas analyzer. 
   
   
       7 . The system of  claim 6  wherein the freezer compartment interlocks further comprises:
 a door handle cover moveably attached to the freezer compartment proximate a door handle, the door handle cover adapted to move between a first position that shrouds the door handle and a second position exposing the door handle; and   a retaining mechanism that is adapted to lock the door handle cover in the first position in response to inputs from the gas analyzer.   
   
   
       8 . The system of  claim 1  wherein the cryogen injection system operates in response to inputs received from the temperature sensor and at a temperature control point that is warmer than a temperature set point associated with the mechanical freezer system. 
   
   
       9 . A method of freezing foodstuffs in a mechanical freezer system comprising the steps of:
 mechanically refrigerating a freezer compartment;   sensing the temperature in the freezer compartment;   selectively injecting a cryogen directly into the freezer compartment based on the temperature of the freezer compartment to cryogenically enhance the freezing of the foodstuffs;   monitoring the concentrations of selected gases within the freezer compartment;   exhausting a portion of the cryogen vapors from the freezer compartment during injection of the cryogen; and   rapidly evacuating the cryogen vapors from the freezer compartment when access to freezer compartment is required.   
   
   
       10 . The method of  claim 9  wherein the cryogen is carbon dioxide and the step of monitoring concentrations of selected gases within the freezer compartment further comprises monitoring concentrations of carbon dioxide within the freezer compartment. 
   
   
       11 . The method of  claim 9  wherein the cryogen is nitrogen and the step of monitoring concentrations of selected gases within the freezer compartment further comprises monitoring concentrations of oxygen within the freezer compartment. 
   
   
       12 . The method of  claim 9  further comprising the step of interlocking any entry into the freezer compartment to prevent access into the freezer compartment when the cryogen is being injected into the freezer compartment. 
   
   
       13 . The method of  claim 9  further comprising the step of interlocking any entry into the freezer compartment to prevent access into the freezer compartment based on concentrations of selected gases within the freezer compartment. 
   
   
       14 . The method of  claim 9  wherein the step of mechanically refrigerating a freezer compartment is based on a temperature control point and injection of cryogen is initiated at a temperature control point that is warmer than the temperature set point.