One Overview of Vacuum Paddle Drying Machine:

1. Wedge shaped hollow blades are densely arranged on the hollow shaft, and the heat medium hot water flows through the blades through the hollow shaft, with a large heat transfer area per unit effective volume. The heat transfer medium flows through the shell jacket and hollow stirring shaft through the rotary joint. The hollow stirring shaft has different internal structures according to the type of heat medium to ensure the best heat transfer effect. At the same time as the blade and jacket are heated by the heat medium, the upper part of the discharge port is vacuum dehumidified, which greatly increases the drying intensity of the equipment. The evaporated water is discharged from the vacuum system through a water ring vacuum pump.
2. The vacuum hollow blade dryer is mainly composed of transmission mechanism, box body, main shaft stirring, bearing body, discharge adjustment mechanism, rotary joint and other components.

3. Power transmission part: mainly composed of electric motor, reducer, driving gear, driven gear, inter shaft gear, etc. Its main function is to transmit the power of the motor to the main shaft mixing part, so that it can operate within the rated speed range. It can also choose variable frequency speed regulation or electromagnetic speed regulation configuration for variable speed operation according to user requirements.
4. Main shaft mixing part: mainly composed of two hollow shafts and several wedge-shaped hollow blades on their surfaces. A heat transfer (heating or cooling) medium (steam, water, oil, etc.) reflux pipe is installed inside the hollow shaft, and the rotating joints configured at both ends or one end are the interfaces for these media to enter and exit. During operation, the main shaft stirring part stirs, pushes, and heats or cools the materials.
5. Bearing body part: Three or two bearing bodies are configured at both ends of the main shaft, consisting of bearings, bearing seats, bearing covers, sealing packing, packing covers, maintenance covers, etc. The power end is equipped with two main and auxiliary bearing bodies. The main bearing body is the main support point of the main shaft and serves as the positioning point for axial movement. The auxiliary bearing body is designed to prevent excessive deformation of the shaft head. The non power end bearing body not only provides the bearing point for the main shaft, but also allows the main shaft to expand and contract freely. Each bearing body is equipped with a cooling structure for the bearings.
6. The discharge adjustment mechanism is mainly composed of an adjustment plate, a rotating shaft, positioning components, etc.

II Application of vacuum blade dryer:
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 stirring blade is also a heat transfer surface, which increases the heat transfer area per unit effective volume and shortens the processing time. The wedge-shaped blade heat transfer surface also has self-cleaning function. The compression expansion mixing function ensures uniform mixing of materials. The material moves in a "piston flow" along the axial direction, and within the axial range, the temperature, humidity, and mixing gradient of the material are very small.
Using thermal oil as the heat medium, the blade dryer can complete low-temperature calcination work. For example, calcium sulfate dihydrate (Ca2SO4 · 2H2O) is calcined and converted into calcium sulfate hemihydrate (Ca2SO4 · 1/2H2O). Sodium bicarbonate (NaHCO3) is converted into pure alkali (Na2CO3) through calcination.
Cooling media such as water, cooling salt water, etc. can be used for cooling. For example, the blade type cooling alkali machine used in the soda ash industry replaces the old-fashioned air-cooled cooling alkali machine, saving energy and exhaust gas treatment equipment, reducing operating costs, and can also be used for cooling titanium dioxide, nickel iron alloy powder, and various granular materials. The material can be cooled from 1000 ℃ to less than 40 ℃ in a single machine.
The main function of the drying 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. It has been widely used in the fine chemical, petrochemical, and dye industries.
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.

III Vacuum blade dryer is suitable for materials:
Petrochemical industry: polyolefin powder, polycarbonate resin, high and low density polyethylene, linear low density polyethylene, polyacetal particles, nylon 6, nylon 66, nylon 12, acetate fiber, polyphenylene sulfide, propylene based resin, engineering plastics, polyvinyl chloride, polyvinyl alcohol, styrene, polypropylene, polyester, formaldehyde, styrene acrylonitrile copolymer, ethylene propylene copolymer.
Environmental protection industry: PTA sludge, electroplating wastewater sludge, boiler ash, pharmaceutical factory waste, sugar factory waste, monosodium glutamate factory waste, coal ash.
Feed industry: soy sauce residue, bone based feed, distiller's grains, food scraps, apple pomace, orange peel, soybean meal, chicken bone feed, fish meal, feed additives, biological sludge
Food industry: starch, cocoa beans, corn kernels, salt, modified starch, pharmaceuticals.
Chemical industry: Soda ash, nitrogen phosphorus potassium compound fertilizer, kaolin, bentonite, white carbon black, carbon black, phosphogypsum, sodium fluoride oxide, calcium nitrate, magnesium carbonate, sodium cyanide, aluminum hydroxide, barium sulfate, calcium sulfate, calcium carbonate, dyes, molecular sieves, saponins.

4 Characteristics of vacuum blade dryer:
The blade dryer has low energy consumption: due to indirect heating, it does not carry a large amount of air to take away heat. The outer wall of the dryer is also equipped with an insulation layer. For slurry materials, evaporating 1kg of water only requires 1.22kg of steam.
The blade dryer system has low cost: it has a huge heat transfer surface per unit effective volume, which shortens processing time and reduces equipment size. This greatly reduces the building area and space.
Wide range of material processing: Using different heat media, it can handle both thermosensitive materials and materials that require high-temperature treatment. Common media include steam, thermal oil, hot water, cooling water, etc. It can operate continuously or intermittently and can be applied in many fields.
Low environmental pollution: No use of portable air, minimal dust and material entrainment. The solvent evaporation of the material is very small, making it easy to handle. For materials that are contaminated or require solvent recovery, closed-loop circulation can be used.
Low operating costs: The device operates normally with only 1-2 people per day. Low speed stirring and reasonable structure. The wear and tear is small, and the maintenance cost is very low.
Stable operation: Due to the special compression expansion stirring effect of the wedge-shaped blade, the material particles are fully in contact with the heat transfer surface. In the axial range, the temperature, humidity, and mixing gradient of the material are very small, thereby ensuring the stability of the process.

Low energy consumption of the dryer: Due to indirect heating, there is no large amount of air carried away to remove heat, and the outer wall of the dryer is also equipped with insulation layer, so the heat loss is very small.

The blade dryer system has low cost: it has a huge heat transfer surface per unit effective volume, which shortens the processing time. The device size has decreased, reducing the footprint.

Wide range of material processing: Using different heat media, it can handle both thermosensitive materials and materials that require high-temperature treatment.

Low environmental pollution: carrying very little air and carrying very little dust material.

Low operating energy consumption cost.

Stable operation: Due to the special compression expansion stirring effect of the wedge-shaped blade, the material particles are fully in contact with the heat transfer area. In the axial range, the temperature, humidity, mixing temperature, and gradient of the material are very small, thereby ensuring the stability of the process.