Cryo containers

Operation Flood was conceived for increasing the availability of milk and milk products in the country.Artificial insemination of cows was a part of this programme.Semen from healthy bulls was collected, stored in liquid nitrogen containers and transported to various animal husbandry centers which in turn distributed it to various user centers.These portable liquid nitrogen containers are also called as cryo containers.
The cryo container is similar to a thermos flask.There is an inner container and an outer container. The inner container is connected to the outer container by a low thermal conductivity fiber tube. Just as in the thermos flask the gap between the inner and the outer container was evacuated to a low pressure. But there is one main difference.
In a conventional thermos flask space between the inner and outer container is evacuated to reduce heat transfer. The outer wall of the inner glass container and inner wall of the outer glass container is silvered to reduce the heat loss by radiation. But in spite of vacuum some heat is transferred by convection.Heat is also lost by conduction through the neck. In a cryo container all these losses are reduced to a low value by unique design which we shall see later.