To cool the air to the required temperature, there is an additional cartridge located just before the conical part, which is filled with dry ice. The cylindrical part of the apparatus ends with a filter designed to catch and prevent fine particles from being carried away by the air stream. The filter is shaken periodically. Air, previously passed through the cartridge with dry ice, is supplied through the inlet opening of the conical part of the apparatus at a speed that provides a stable hydrodynamic regime. At the chamber outlet, the air is sequentially supplied for purification, heating and drying.

Atmospheric freeze drying under conditions of convective heat supply allows: to intensify the process of moisture removal ten times; to significantly reduce the time of its implementation, while obtaining products that are not only not inferior in preserving useful properties to those freeze-dried in vacuum, but also superior to them in some qualitative characteristics; to organize the process not only in periodic, but also in semi-continuous and continuous modes. Scientists have demonstrated the suitability of atmospheric freeze drying for the treatment of coarse materials. However, due to the significant particle size (more than 1 cm) the process duration was an order of magnitude higher in comparison with vacuum freeze drying. To reduce the process time, part of the moisture was preliminarily removed by osmotic dehydration.