The QJ Series Hollow Paddle Dryer provides indirect heating through hollow paddles with continuous agitation. Typical materials and duties include pastes, cakes, powders and granules suitable for paddle drying.

Paddle dryers have been successfully used in fields such as food, chemicals, petrochemicals, dyes, and industrial sludge. The equipment's characteristics of heat transfer, cooling, and mixing enable it to perform the following unit operations: combustion (low-temperature), cooling, drying (solvent recovery), heating (melting), reaction, and sterilization. The stirring paddles also serve as heat transfer surfaces, increasing the heat transfer area per unit of effective volume and shortening processing time. The wedge-shaped paddle heat transfer surface also has a self-cleaning function. The compression-expansion stirring function ensures uniform mixing of materials. The material moves axially in a "plug flow" pattern, and within the axial zone, the temperature, humidity, and mixing degree gradients of the material are very small. Using heat transfer oil as the heating medium, the paddle dryer can perform low-temperature combustion work. For example: calcium sulfate dihydrate (Ca₂SO₄·2H₂O) is converted to calcium sulfate hemihydrate (Ca₂SO₄·1/2H₂O) through combustion. Sodium bicarbonate (NaHCO₃) is converted to soda ash (Na₂CO₃) through combustion, etc. By introducing a cooling medium such as water or cooled brine, it can be used for cooling. For example: the paddle-type soda ash cooler used in the soda ash industry replaces the old air-cooled soda ash cooler, saving energy and tail gas treatment equipment, and reducing operating costs. Drying, the most important function of the equipment, does not use hot air, making solvent recovery, energy consumption, and environmental control in an ideal state that is easy to handle. It is particularly suitable for materials requiring solvent recovery, flammable, easily oxidized, and heat-sensitive materials. It has been widely used in fine chemicals, petrochemicals, and dye industries. Within the axial zone, the uniformity of temperature, humidity, and mixing degree allows the equipment to be used for heating or melting, or for conducting some solid material reactions. It has been successfully used in the compound fertilizer and modified powder industries. The paddle dryer can be used for sterilization treatment of food and flour. The large heating area per unit of effective volume quickly heats the material to the sterilization temperature, avoiding prolonged heating that would alter the material quality.