Cryogenic Liquid Safety

Dewars: A dewar flask consists of a double walled vessel with a vacuum between the two walls.  The vacuum provides an excellent thermal insulation, so that cold or hot liquids can be stored in them for a period of time.  The walls can be constructed from various materials, usually glass or stainless steel.  The thermos bottle is a common example of a dewar.  Many use a glass dewar that is protected by a metal or plastic exterior container. 

Examples of liquid nitrogen vessels; all are frequently referred to as "Dewars."

Dewar Flask HDPE 1 Liter about $100

Also in 2 and 4 L with handle.  OK for temperatures from -196 to 100C

This type is not vacuum insulated.

 

Dewar flask borosilicate glass inner vacuum insulated flask with a stainless steel outer container 1 Liter, about $140

Dewar flask cylindrical silvered borosilicate glass 375mL
about $60

  

Fisher-Brand Metal-Cased cylindrical, in various sizes from 0.75 qt to 4.5 qt, with and without handle, $90 - $240
From catalogue text: "Provide safe and efficient storage and handling of liquid nitrogen.  Lightweight design makes them ideal for everyday laboratory use.  Narrow neck and vacuum insulation keep evaporation rates low.  Durable aluminum, double-wall construction ensures years of trouble-free service even with the rough handling associated with portable cryogenic equipment.  Pail-style handle on the Thermo 5 and 10 makes pouring easy even in hard-to-reach places. Thermo 20 and 30 offer the same lightweight design and low liquid nitrogen consumption rate in a larger Dewar.  Thermo 35 and 50 are pressurized cylinders designed for researchers who need a continuous source of liquid nitrogen but lack space for larger cylinders.  Relief valve setting on the 35- and 50-liter models is 22psi.  About $1000 for the 30 L model."
Dipper, 12 mL, for removing nitrogen from the Dewar.  

El-cheapo - the plastic mesh covered version with no handle.  Borosilicate glass. Metal casing surrounds only bottom portion of flask. Protective plastic mesh covers remaining outer surface of glass. Special vented polyethylene stopper minimizes evaporation and potential for splashing when moving (If you use it.).

$67 - 205 for 665 mL - 4300 mL sizes
Stainless Steel Vacuum-Insulated Dewars

25, 35 and 50 L capacities available

With static evaporation rates as low as 0.7L/24h

photo shows ES-25 & ES-50 dewars with optional pouring trolley, tipping stand & 50KF dispensing head, from CRYOTECHNICS. Albion Industrial Estate,78 Albion Road,Edinburgh. EH7 5QZ. UK.

      

This upright tank is a stainless steel 180 L self pressurizing vessel which is used to store, fill & dispense liquid nitrogen to storage refrigerators or other containers,

Wheels such as shown here are acceptable for transport across inner hallways surfaces, elevator thresholds, or onto scales if the wheels are 3" diameter or greater and the wheel width is larger than the gaps over which the vessel must travel.