Abstract: A vacuum-tight coat of the cryostat encloses a thermally insulated vessel, intended to keep cryogenic products, so that between the surfaces of said elements there is a heat-insulating cavity from which air is evacuated. In order to build up vacuum in the cavity a vacuum valve on the vacuum-tight coat is provided. Between the inlet opening of the vacuum valve and the thermally insulated vessel, there is disposed a cup which is fixed rigidly in the heat insulating cavity. The cup has perforations evenly distributed on its lateral surfaces.The heat-insulating cavity of the proposed cryostat, having the capacity of 47 liters, should be evacuated for 7 days at the capacity of the evacuating system of 200 liters (at STP) per hour. In other words, owing to the special design of the vacuum valve, the evacuation of the heat-insulating cavity of the cryostat is effected in accordance with the capacity of the evacuation system, and the vacuum-multilayer insulation remains intact during this process.

Abstract: A cryostat comprising a thermally insulated vessel intended to store cryogenic products and provided with a neck tightly closed with a stopper. Between the inner surface of the neck and the stopper there a helical channel is formed through which the vapor of the cryogenic product is withdrawn to the atmosphere. The ratio of the length of the helical channel to the cross-sectional area thereof is such that the excessive vapor pressure of the evaporating cryogenic products in the vessel is eliminated while the temperature of the vapor at the outlet of the neck corresponds to the temperature of the ambient atmosphere. In this way a cryostat of 34 liter capacity can be used to store biological materials at the temperature of liquid nitrogen for at least 120 days.The proposed cryostat can be used to store biological materials at the temperature of liquid nitrogen for at least 120 days. The capacity of the cryostat is 34 liters.