초록 ▼

The particles of the particulate material to be dried are cooled before the drying operation proper, or in the initial phase thereof, to a temperature low enough to make the liquid to be extracted solidify. At least the drying operation proper is carried out in a space bounded by a container, in whi

The particles of the particulate material to be dried are cooled before the drying operation proper, or in the initial phase thereof, to a temperature low enough to make the liquid to be extracted solidify. At least the drying operation proper is carried out in a space bounded by a container, in which a gas, more particularly air, is passed through the particles. While in said space, the particles are subjected to motion, for example, they are whirled by the gas to form a whirling layer. The temperature of the gas is adjusted to have at least a considerable part of the drying operation take place by sublimation, the heat energy required for the sublimiation being supplied to the particles at least in part by the gas passed through them. In this way, the particulate material may be dried with care and nevertheless in relatively large batches, and with limited time expenditure.

대표청구항 ▼

A process for drying particulate material that includes a liquid substance to be extracted, the process comprising the steps of: freezing the material within a container in a freezing operation and subsequently drying the material in the same container in a drying operation, wherein a cooling medium

A process for drying particulate material that includes a liquid substance to be extracted, the process comprising the steps of: freezing the material within a container in a freezing operation and subsequently drying the material in the same container in a drying operation, wherein a cooling medium having one of the states solid and liquid and particles of the said material are subjected to movement during the said freezing operation in the said container, so that the particles of the material are cooled to a temperature at which the liquid substance is solidified and wherein the cooling medium is separated from the particulate material in the gaseous state, and wherein the particulate material, after the solidification of the liquid substance is dried during the drying operation in the same container by passing gas through the particulate material and subjecting the particulate material to motion, wherein the particulate material is held at least during a part of the drying operation at a temperature at which at least a part of the substance to be extracted from it remains in the solid state until it is extracted by sublimation, and wherein vapor generated during the drying operation is carried away from the particulate material by the gas passed through the particulate material together with said gas.