Rake type vacuum dryer

vacuum rake dryerWorking Principle:
It is mainly composed of a shell, a rotating shaft, and rake teeth. Unlike the blade dryer, the rotating shaft and rake teeth do not serve as heating surfaces, but only serve to stir the material and renew the surface. The rake dryer is vacuum operated. First, wet materials are added to the dryer, and a heating medium (usually steam or hot water, or thermal oil can also be used) is introduced into the jacket. Then, the vacuum pump is started to reach the specified vacuum degree, and the mixing device is started. The rake teeth rotate forward and backward to continuously push the material towards the middle and both ends during the drying process. At the same time, four stainless steel rods (seamless steel pipes) can also be placed between the rake teeth according to user requirements. It continuously moves up and down during the rotation of the shaft, vibrating the material bonded to the wall and crushing the clumped material. Through these measures, timely updates of the heat transfer surface can be ensured, thereby accelerating the rate of heat and mass transfer. When the material is dried to the specified moisture content, stop heating, turn off the vacuum system, remove the dried material, and complete one cycle of operation. This dryer is suitable for drying pulp, paste, granular, and fibrous materials, especially for heat sensitive materials and drying operations that require the recovery of organic vapors, and has many advantages. There are two basic forms of rake teeth: left and right. There are two types of rake teeth: irregular and blade shaped. When installing, adjacent rake teeth are positioned 90 degrees apart, and irregular rake teeth are installed at both ends of the shaft, while blade shaped rake teeth are installed at the rest. When the shaft rotates, the material moves to both sides first and then to the middle under the action of the mixing shaft, which ensures that the material is in a uniform mixing state throughout the entire drying process.

The commonly used drying medium is steam, thermal oil or hot water with a pressure range of 0.1-0.3Mpa. The vacuum degree inside the dryer is 50-90kPa, the filling rate of the material is 30% -80%, and the thermal efficiency is 70% -80% The speed of the shaft is continuously adjustable from 6-30rpm.

vacuum rake dryerMainly used for:
Dry materials in industries such as pharmaceuticals, food, and chemicals;
Slurry, paste like, and powdery materials;
Thermally sensitive materials that require low-temperature drying;
Easily oxidizable, explosive, strongly irritating, and highly toxic materials;
Require the recycling of materials containing organic solvents.

Features:
Adopting the method of simultaneous heating with interlayer and internal stirring, the heat transfer surface is large and the thermal efficiency is high.
By setting up agitation, the material is continuously circulated in the cylinder, further improving the uniformity of material heating.
Set up agitation to facilitate the smooth drying of slurry, paste, and paste like materials.