Energy efficient biological freezer with vial management system
An automated, ultra-low temperature freezer having multiple structural features that reduce heat transfer into the freezer, protect its internal mechanical devices against low temperature mechanical binding of their movements, allow defrosting and autoclaving as a result of only minimal changes to the conventional CO 2 emergency backup system. A group of freezers are arranged so they can simultaneously provide an HVAC function. A vial management system allows biological samples or vials to be automatically placed in and recovered from the freezer and associates the temperature history with each sample or vial that it was subjected to during its storage.
1. An ultra-low temperature freezer having an enclosed cabinet including a surrounding wall of thermal insulation having an interior side and an exterior side and a refrigerating apparatus, the freezer also having an inlet pipe for connection at one end to a container that is a source of CO 2 and connected at its opposite end into the freezer, the inlet pipe having a valve interposed in the pipe for controlling the inflow of CO 2 into the freezer, the freezer comprising:
(a) said source of CO 2 being a liquid CO 2 container; and
(b) an inline heater also interposed in the inlet pipe for heating inflowing CO 2 to allow the freezer to be defrosted or autoclaved.
2. An ultra-low temperature freezer in accordance with claim 1 wherein the heater is connected to a heat energy source and has a switch or valve for selectively turning the heat energy source on and off.
3. A method for defrosting or autoclaving an ultra-low temperature freezer having an enclosed cabinet including a surrounding wall of thermal insulation and a refrigerating apparatus, the freezer also having an inlet pipe for connection at one end to a container that is a source of CO 2 and connected at its opposite end into the freezer, the inlet pipe having a valve interposed in the pipe for controlling the inflow of CO 2 into the freezer, the method comprising:
(a) flowing the CO 2 from a liquid CO 2 container through the inlet pipe; and
(b) heating the CO 2 from the CO 2 container during inflow of the CO 2 through the pipe into the freezer for defrosting or autoclaving the interior of the freezer.
4. A method in accordance with claim 3 wherein the method further comprises heating the CO 2 to a temperature of at least zero degrees C.
5. A method in accordance with claim 4 wherein the method further comprises heating the CO 2 to a temperature sufficient to kill living organisms within the freezer.