The thin film evaporator unit consists of three main components: evaporator, vapor-liquid separator, and preheater, as well as a simple separator. The evaporator is a rising film tube heat exchanger. This evaporator has the characteristics of high production capacity, high efficiency, and short heating time of materials, and is suitable for dilute solution concentration in industries such as pharmaceuticals, food, and chemicals. The parts in contact with the materials of this equipment are made of OCr19Ni9 stainless steel, which has good corrosion resistance and durability, meeting the requirements of pharmaceutical hygiene.