Cryogenic freezer

Abstract

A cryogenic freezer features a dewar defining a storage space. A reservoir is positioned within or adjacent to the storage space and is configured to contain a cryogenic liquid with a headspace above the cryogenic liquid in a reservoir interior space that is sealed with respect to the storage space. A refrigeration module is in heat exchange relationship with the reservoir. A sensor is configured to determine a temperature or pressure within the reservoir. A system controller is connected to the sensor and the refrigeration module and configured so that the refrigeration module is adjusted to provide additional cooling to the reservoir when a pressure or temperature within the headspace increases.

What is claimed is: 
     
         1 . A cryogenic freezer comprising:
 a container defining a storage space;   a reservoir vessel positioned within the storage space and configured to contain a cryogen and a void space in a reservoir interior space that is sealed with respect to the storage space by a wall of the reservoir vessel;   a refrigeration module that is in a heat exchange relationship with the void space of the reservoir,   wherein the refrigeration module includes a cold tip that is in the heat exchange relationship with the void space of the reservoir and that is positioned in an upper end of the reservoir vessel;   a sensor configured to monitor a characteristic of the reservoir interior space; and   a system controller connected to the sensor and the refrigeration module and configured to control an amount of cooling by the refrigeration module to the cold tip in response to a detected value of the characteristic,   wherein the wall of the reservoir vessel cools the storage space by heat transfer through the wall of the reservoir vessel and prevents fluid communication between the storage space and the reservoir interior space.   
     
     
         2 . The cryogenic freezer of  claim 1 , wherein the refrigeration module is removably mounted to the container. 
     
     
         3 . The cryogenic freezer of  claim 1 , wherein the reservoir is secured within the container by a reservoir neck that is in fluid communication with the void space of the reservoir. 
     
     
         4 . The cryogenic freezer of  claim 1 , wherein the refrigeration module includes a housing, and wherein the housing includes a divider wall that separates an interior of the housing into a front compartment which includes the system controller and air intake opening and a rear compartment that includes a motor of the refrigeration module and an air outlet opening. 
     
     
         5 . The cryogenic freezer of  claim 4  further comprising a baffle wall positioned within the rear compartment of the housing and opposing the air outlet opening. 
     
     
         6 . The cryogenic freezer of  claim 5 , wherein the refrigeration module includes a heat sink positioned adjacent to the air intake opening. 
     
     
         7 . The cryogenic freezer of  claim 5 , wherein the air outlet opening includes cooling slots positioned in a back panel of the housing. 
     
     
         8 . The cryogenic freezer of  claim 1 , wherein the refrigeration module includes a housing that is removably mounted to the container and wherein the reservoir is secured within the container by the reservoir neck. 
     
     
         9 . The cryogenic freezer of  claim 8 , wherein the cold tip is configured to be removable from the reservoir neck with the refrigeration module housing, wherein the refrigeration module housing is removable from the container. 
     
     
         10 . The cryogenic freezer of  claim 1 , wherein the container comprises a dewar, wherein the dewar includes an inner wall surrounded by an outer wall with a vacuum insulation space there between. 
     
     
         11 . The cryogenic freezer of  claim 1 , wherein the container includes an access neck defining an access opening with a lid removably covering the access opening, the lid including a top plate, a plug and a gasket ring, where the gasket ring engages the access neck to seal the access opening when the plug is received in the access opening to close the lid. 
     
     
         12 . The cryogenic freezer of  claim 11 , wherein the access neck includes a removable gasket sleeve that is engaged by the gasket ring when the lid is in the closed configuration. 
     
     
         13 . The cryogenic freezer of  claim 1 , wherein the refrigeration module is configured to run at a steady-state running level to provide cooling to the void space of the reservoir to balance heat leak to the reservoir from outside environment or when the detected value of the characteristic within increases, wherein the characteristic is a pressure or temperature within the reservoir interior space. 
     
     
         14 . The cryogenic freezer of  claim 1 , wherein the refrigeration module is configured to condense vapor in the void space of the reservoir when the refrigeration module is configured to increase the amount of cooling to the cold tip from the steady-state running level. 
     
     
         15 . The cryogenic freezer of  claim 1 , wherein the wall of the reservoir vessel cools a stored material in the storage space by the heat transfer through the wall of the reservoir vessel. 
     
     
         16 . A cryogenic freezer comprising:
 a container defining a storage space;   a reservoir vessel positioned within the storage space and configured to contain a cryogen in a reservoir interior space that is sealed with respect to the storage space by a wall of the reservoir vessel;   a refrigeration module including a cold tip that is in a heat exchange relationship with the reservoir vessel;   a content monitoring apparatus configured to monitor the reservoir interior space; and   a system controller connected to the content monitoring apparatus and the refrigeration module and configured to control cooling by the refrigeration module to the reservoir vessel in response to a change in the cryogen in the reservoir interior space,   wherein the wall of the reservoir vessel cools the storage space by heat transfer through the wall of the reservoir vessel and prevents fluid communication between the storage space and the reservoir interior space.   
     
     
         17 . A freezer comprising:
 a container defining a storage space;   a reservoir vessel positioned within the storage space and configured to contain a cryogen with a headspace above the cryogen in a reservoir interior space that is sealed with respect to the storage space by a wall of the reservoir vessel;   a refrigeration module that is in a heat exchange relationship with the headspace,   wherein the refrigeration module includes a cold tip that is in the heat exchange relationship with the headspace and that is positioned in an upper end of a reservoir neck of the reservoir;   a sensor configured to determine a pressure or temperature corresponding to a pressure or temperature within the reservoir interior space; and   a system controller connected to the sensor and the refrigeration module and configured to control an amount of cooling by the refrigeration module to the cold tip in the headspace when the pressure or the temperature within the reservoir interior space increases,   wherein the reservoir vessel cools the storage space by heat transfer and prevents fluid communication between the storage space and the reservoir interior space.   
     
     
         18 . The freezer according to  claim 17 , wherein the freezer is a cryogenic freezer. 
     
     
         19 . The freezer according to  claim 17 , wherein the reservoir vessel is secured within the container by the reservoir neck that is in fluid communication with the headspace of the reservoir. 
     
     
         20 . The freezer according to  claim 17 , wherein the wall of the reservoir vessel cools a stored material in the storage space by the heat transfer through the wall of the reservoir vessel.