The Dewar Rack provides a compact, convenient way to organize and reliably dry your 4L LN2 dewars. It comes in an active version, which automatically starts a drying cycle upon placing a dewar upon it and dries it out completely in 35 minutes, and a passive version, which provides a way to organize your 4L dewars after being dried on your active Dewar Rack. 
 
The ubiquitous 4L dewars are the workhorse dewar for many labs, and after use there has not been a convenient, reliable way to dry them quickly so that you or colleagues can be assured that they are moisture-free and ready to use for their experiments without the risk of contamination. A 4L dewar is placed upside-down onto the active Dewar Rack, with the drying tube being inserted into the dewar. The dewar is automatically sensed by the Dewar Rack and a drying cycle commenced. Ambient air is pulled through a filter, ensuring only clean air is being used, and heated before being blown into the dewar. The system is configured to run for as much time as needed to dry a dewar completely, and a short cooling phase is included at the end to bring the dewar to room temperature. 
 
An LED under the rack provides an easy way for users to know when the drying cycle is complete, or what stage the cycle is at during drying. The dewar rack is compatible with both MVE and ICBiomedical 4L dewars. The passive version of the Dewar Rack then provides a convenient way to organize all of your 4L dewars after being taken off of the active version, keeping that version available for drying.