Vacuum rake dryers indirectly heat materials using a steam jacket and exhaust air under high vacuum. Therefore, they are particularly suitable for drying materials that are not heat-resistant, easily oxidized at high temperatures, or prone to powdering during drying (such as various fuels), as well as materials where the steam or solvent discharged during the drying process must be recovered. A comparative analysis of the hot spots in vacuum rake dryer production reveals that, under the continuous stirring of the rotating rake teeth, the surface of the material is constantly renewed when it comes into contact with the shell wall. The material being dried is indirectly heated by steam, which facilitates the removal of internal and surface moisture from the material and promotes the movement of water molecules, thus achieving the drying purpose. The vacuum rake dryer's rake teeth rotate continuously in both directions, ensuring even mixing of the material being dried. This prevents overheating and excessive moisture loss, resulting in a low-temperature product. However, this intermittent operation leads to long drying times and low output. Furthermore, the difficulty in clearing material makes it unsuitable for production processes involving frequent product changes.
During the continuous rotation of the rake teeth, the material's surface is constantly renewed as it contacts the shell wall. The material is indirectly heated by steam, facilitating the removal of internal and surface moisture and promoting the movement of water molecules, thus achieving the drying objective.
The vacuum rake dryer's continuous rotation of the rake teeth ensures even mixing of the material, preventing overheating and excessive moisture loss. The sealing system can be either a packing seal or a mechanical seal, with a special design ensuring both sealing performance and service life.
The vacuum rake dryer, with its continuously rotating rake teeth agitating the material, causes constant surface renewal as the material contacts the shell wall. The material is indirectly heated by steam, making it a novel horizontal, intermittent vacuum drying device. Wet material evaporates through conduction, while a scraper agitator continuously removes material from the heated surface, creating a circulating flow within the container. After evaporation, the water is extracted by a vacuum pump.
The vacuum rake dryer boasts impressive output, capable of handling materials with moisture or solvent content ranging from as low as 15% to as high as 90%. Utilizing a jacketed heating system and simultaneous rake tooth heating, it offers a larger heat transfer area and higher thermal efficiency, resulting in superior drying efficiency. This process promotes the movement of water molecules in the material, achieving the desired drying effect.
The vacuum rake dryer is particularly suitable for drying materials that are easily oxidized at high temperatures, materials that easily produce powder during drying (such as various fuels), and materials where the steam or solvent released during the drying process must be recovered. It is especially suitable for drying heat-sensitive, flammable, and easily oxidized paste-like materials that are prone to oxidation under controlled temperature conditions.
The vacuum rake dryer is a novel horizontal intermittent vacuum drying device. Wet materials undergo conduction evaporation, with a scraper agitator continuously removing material from the heated surface and creating a circulating flow within the container. After evaporation, the moisture is extracted by a vacuum pump, facilitating the removal of internal and surface moisture from the material and promoting the movement of water molecules to achieve the drying objective.
The vacuum rake dryer operates in a closed drying environment, eliminating dust. With appropriate auxiliary equipment, a dust-free working chamber can be maintained. The device indirectly heats the material using a steam jacket and exhausts the air under high vacuum, making it particularly suitable for materials that are not heat-resistant, easily oxidized at high temperatures, or prone to powder formation during drying.
