Multi-zone low temperature freezer

Abstract

A freezer provides multiple zones of temperature for preserving a frozen product at an ultra-low temperature. At least one first housing provides a first interior space at a first predetermined temperature. A first compressor, condenser and metering device supply a first refrigerant to a first evaporator for lowering the temperature in the first interior space to the first predetermined temperature. At least one second housing is mounted totally within the first interior space and provides a second interior space for defining a second freezing zone at a second predetermined temperature. The second predetermined temperature is lower relative to the first predetermined temperature. A second compressor, condenser and metering device supply a second refrigerant to a second evaporator for freezing the second housing to the second predetermined temperature. The second compressor, condenser and metering device are disposed within the first interior space to the first evaporator.

1 . A freezer for providing multiple zones of temperature for preserving a frozen product at an ultra-low temperature comprising:
 at least one first housing providing a first interior space for defining a first refrigerated zone at a first predetermined temperature;   a first compressor being operatively connected to a first condenser and a first metering device for supplying a first refrigerant to a first evaporator disposed within said first interior space for cooling said first interior space to said first predetermined temperature;   at least one second housing mounted totally within said first interior space, said at least one second housing providing a second interior space for defining a second freezing zone at a second predetermined temperature, said second predetermined temperature being lower relative to said first predetermined temperature; and   a second compressor being operatively connected to a second condenser and a second metering device for supplying a second refrigerant to a second evaporator disposed within said at least one second housing for freezing said at least one second housing to said second predetermined temperature, said second compressor, said second condenser and said second metering device being disposed within said first interior space and being exposed to said first evaporator;   wherein said first predetermined temperature within said first interior space provides a working environmental temperature relative to said second predetermined temperature which is an ultra-low temperature that is not suitable as a working environment.   
   
   
       2 . The freezer according to  claim 1 , wherein said at least one second housing is a freezer that is completely disposed within said first interior space, said freezer being operated with the second compressor, the second condenser and the second metering device being exposed to the first refrigerated zone wherein the freezer reduces the temperature within said second freezing zone to be the ultra-low temperature relative to said first predetermined temperature within said first refrigerated zone. 
   
   
       3 . The freezer according to  claim 1 , wherein said first predetermined temperature is in a range of approximately −20 to +40 degrees Fahrenheit, −28.9 to +4.4 Celsius and the second predetermined temperature is in a range of approximately −40 to −70 degrees Fahrenheit, −40 to −56.7 Celsius. 
   
   
       4 . The freezer according to  claim 1 , wherein said at least one first housing is a walk-in housing and said at least one second housing is disposed within said walk-in housing to enable a working environmental temperature within said at least one first housing while maintaining the at least one second housing at said ultra-low temperature. 
   
   
       5 . The freezer according to  claim 4 , wherein a plurality of second housings is disposed within said first housing. 
   
   
       6 . The freezer according to  claim 1 , wherein said at least one first housing is a freezer and said at least one second housing is a freezer disposed within said at least one first housing. 
   
   
       7 . The freezer according to  claim 1 , and further including a first thermostat for regulating the first predetermined temperature within said at least one first housing to be in a range of approximately −20 to +40 degrees Fahrenheit, −28.9 to +4.4 Celsius. 
   
   
       8 . The freezer according to  claim 7 , and further including a second thermostat for regulating the second predetermined temperature within said at least one second housing to be in a range of approximately −40 to −70 degrees Fahrenheit, −40 to −56.7 Celsius. 
   
   
       9 . The freezer according to  claim 1 , wherein an atmosphere within said first interior space that is at the first predetermined temperature is the medium for cascading the second predetermined temperature within said second interior space to be an ultra-low freezing temperature. 
   
   
       10 . A freezer for providing multiple zones of temperature for preserving a frozen product at an ultra-low temperature comprising:
 at least one first housing providing a first interior space for defining a first refrigerated zone at a first predetermined temperature;   a first compressor being operatively connected to a first condenser and a first metering device for supplying a first refrigerant to a first evaporator disposed within said first interior space for cooling said first interior space to said first predetermined temperature;   at least one second housing mounted totally within said first interior space, said at least one second housing providing a second interior space for defining a second freezing zone at a second predetermined temperature, said second predetermined temperature being lower relative to said first predetermined temperature; and   a second compressor being operatively connected to a second condenser and a second metering device for supplying a second refrigerant to a second evaporator disposed within said at least one second housing for freezing said at least one second housing to said second predetermined temperature, said second compressor, said second condenser and said second metering device being disposed within said first interior space and being exposed to said first evaporator.   
   
   
       11 . The freezer according to  claim 10 , wherein said at least one second housing is a freezer that is completely disposed within said first interior space, said freezer being operated with the second compressor, the second condenser and the second metering device being exposed to the first refrigerated zone wherein the freezer reduces the temperature within said second freezing zone to be the ultra-low temperature relative to said first predetermined temperature within said first refrigerated zone. 
   
   
       12 . The freezer according to  claim 10 , wherein said first predetermined temperature is in a range of approximately −20 to +40 degrees Fahrenheit, −28.9 to +4.4 Celsius and the second predetermined temperature is in a range of approximately −40 to −70 degrees Fahrenheit, −40 to −56.7 Celsius. 
   
   
       13 . The freezer according to  claim 10 , wherein said at least one first housing is a freezer and said second housing is a freezer disposed within said first housing. 
   
   
       14 . The freezer according to  claim 10 , and further including a first thermostat for regulating the first predetermined temperature within said at least one first housing to be in a range of approximately −20 to +40 degrees Fahrenheit, −28.9 to +4.4 Celsius. 
   
   
       15 . The freezer according to  claim 14 , and further including a second thermostat for regulating the second predetermined temperature within said at least one second housing to be in a range of approximately −40 to −70 degrees Fahrenheit, −40 to −56.7 Celsius. 
   
   
       16 . The freezer according to  claim 10 , wherein an atmosphere within said first interior space that is at a first predetermined temperature is the medium for cascading the second predetermined temperature within said second interior space to be an ultra-low freezing temperature. 
   
   
       17 . A freezer for providing multiple zones of temperature for preserving a frozen product at an ultra-low temperature comprising:
 at least one first housing providing a first interior space for defining a first refrigerated zone at a first predetermined temperature;   a first compressor being operatively connected to a first condenser and a first metering device for supplying a first refrigerant to a first evaporator disposed within said first interior space for cooling said first interior space to said first predetermined temperature;   at least one second housing mounted totally within said first interior space, said at least one second housing providing a second interior space for defining a second freezing zone at a second predetermined temperature, said second predetermined temperature being lower relative to said first predetermined temperature; and   a second compressor being operatively connected to a second condenser and a second metering device for supplying a second refrigerant to a second evaporator disposed within said at least one second housing for freezing said at least one second housing to said second predetermined temperature, said second compressor, said second condenser and said second metering device being disposed within said first interior space and being exposed to said first evaporator.   
   
   
       18 . The freezer according to  claim 17 , wherein said at least one second housing is a freezer that is completely disposed within said first interior space, said freezer being operated with the second compressor, the second condenser and the second metering device being exposed to the first refrigerated zone wherein the freezer reduces the temperature within said second freezing zone to be the ultra-low temperature relative to said first predetermined temperature within said first zone. 
   
   
       19 . The freezer according to  claim 17 , wherein said first predetermined temperature is in a range of approximately −20 to +40 degrees Fahrenheit, −28.9 to +4.4 Celsius and the second predetermined temperature is in a range of approximately −40 to −70 degrees Fahrenheit, −40 to −56.7 Celsius. 
   
   
       20 . The freezer according to  claim 17 , wherein a plurality of second housings is disposed within said first housing. 
   
   
       21 . The freezer according to  claim 17 , wherein said at least one first housing is a freezer and said at least one second housing is a freezer disposed within said first housing. 
   
   
       22 . The freezer according to  claim 17 , and further including a first thermostat for regulating the first predetermined temperature within said at least one first housing to be in a range of approximately −20 to +40 degrees Fahrenheit, −28.9 to +4.4 Celsius. 
   
   
       23 . The freezer according to  claim 22 , and further including a second thermostat for regulating the second predetermined temperature within said at least one second housing to be in a range of approximately −40 to −70 degrees Fahrenheit, −40 to −56.7 Celsius. 
   
   
       24 . The freezer according to  claim 17 , wherein an atmosphere within said first interior space that is at a first predetermined temperature is the medium for cascading the second predetermined temperature within said second interior space to be an ultra-low freezing temperature.