“Jagdish” vacuum driers are built in series for different capacities. The process of vacuum drying is shown in the flow chart. The base soap resulting from saponification is pumped in to the drier continuously by speed regulation of the proportioning pump. The pumps are especially suited for viscous mediums and easy to maintain. The heat exchangers are designed for a proper heating steam pressure and a feeding temperature. They are reconciled to the special demands of soap drying where the evaporation of water already starts in the heat exchanger.