Blade drying machine - Overview of pilot equipment
Hollow blade dryer is a horizontal stirring type continuous drying equipment mainly based on heat conduction. Due to the shape of the stirring blades resembling ship propellers, it is called blade dryer. It is also known as trough dryer or stirring dryer in foreign countries. Due to the indirect heating required for equipment drying through thermal conduction, the drying process does not require or only requires a small amount of gas to remove moisture. Greatly reducing the heat loss carried away by the airflow and improving the heat utilization efficiency, it is an energy-saving drying equipment. Paddle dryers are widely used in industries such as petrochemicals, chemicals, metallurgy, food, pharmaceuticals, pesticides, etc. for drying powdered, granular, filter cake, and slurry materials.

Blade dryer -3D diagram of pilot equipment

Blade drying machine - working principle of pilot equipment
The heat transfer surface of the hollow blade dryer consists of several parts such as blades, stirring shafts, and walls, and the heat transfer area of the blades accounts for a large part. Therefore, the equipment has a compact structure and a large heat transfer area per unit volume. In addition, stirring and mixing cause the material to vigorously flip, thereby achieving a high heat transfer coefficient, resulting in a small footprint and space, saving on factory construction costs. The drying process requires less gas and has a low flow rate, resulting in less dust being carried away by the gas. Therefore, the recovery of gas and dust after drying is convenient, and the recovery equipment has a small volume, which can save equipment investment.
Due to the unique structure of the blade, the material is subjected to alternating compression and relaxation during the drying process, which enhances the drying process. The filling rate of materials in the drying room is very high, which can reach 80% to 90%. The residence time of materials can be adjusted by adjusting parameters such as feeding speed, stirring shaft speed, and material filling degree, and can be adjusted arbitrarily from a few minutes to a few hours. In addition, the material in the dryer moves from the feeding port to the discharging port in a piston motion, with a narrow residence time distribution, resulting in a uniform moisture content of the product. The blade has a certain axial angle on the mixing shaft, so it can continuously dry materials.

Paddle dryer - Application scope of pilot equipment
The paddle dryer has been successfully used in fields such as food, chemical, petrochemical, dye, and industrial sludge. The characteristics of heat transfer, cooling, and stirring of the equipment enable it to perform the following unit operations: calcination (low temperature), cooling, drying (solvent recovery), heating (melting), reaction, and sterilization.
The main function of the equipment is to not use hot air, so that solvent recovery, energy consumption, and environmental control are in an ideal state that is easy to handle. It is particularly suitable for solvents that need to be recycled, flammable and easily oxidizable heat sensitive materials. The uniformity of temperature, humidity, and mixing degree within the axial range allows the equipment to be used for heating or melting, or for some solid material reactions. It has been successfully used in the compound fertilizer and modified starch industries. Paddle dryers can be used to sterilize food and flour. The large heating area within the effective volume of the unit quickly heats the material to the sterilization temperature, avoiding prolonged heating and changing the quality of the material.

Blade drying machine - Performance characteristics of pilot equipment
1. Low energy consumption and low operating costs: compact equipment structure, large effective heat transfer area, and small footprint;
2. Wide range of applicable materials: using different heat media, it can handle both thermosensitive materials and materials that require high temperature drying. Common media include steam, thermal oil, hot water, cooling water, etc. It can be dried continuously or intermittently, and can be applied in many fields.
3. Mixing evenly, high thermal efficiency, and good drying effect;
4. The propeller shaft can mesh with each other and has a self-cleaning function to prevent material from sticking to the wall;
5. Small dust entrainment, minimal material loss, and low environmental pollution; For materials that are contaminated or require solvent recovery, closed-loop circulation or vacuum drying can be used.