Vacuum Belt Dryer

Overview

  The vacuum belt dryer is a contact-type vacuum drying equipment with continuous feeding and continuous discharging. The feed liquid to be dried enters the interior of the dryer, which is under high vacuum, directly through a conveying mechanism, and is spread onto several drying belts inside the dryer. A specially designed rubber roller driven by a motor drives the drying belts to move along the direction of the dryer cylinder at a set speed. Beneath each drying belt are three independent heating plates and one cooling plate. The drying belt fits tightly against the heating plates and cooling plate, transferring the energy required for drying to the material by means of contact heat transfer. When the drying belt moves from one end of the cylinder to the other, the material has already been dried and cooled. When the drying belt returns, the dried material cake is peeled off the belt and knocked down into a crushing device by a vertically moving chopping device. The crushed material is discharged through two airlock-type discharge hoppers. Since the material directly enters a high vacuum environment and is gradually dried over a period of time (usually 30–60 minutes), the resulting granules have a certain degree of crystallization effect and, from a microscopic perspective, contain micropores. After being directly crushed to the required particle size, the granules have good flowability and can be directly tableted or filled into capsules. At the same time, because the granules have a microscopic loose structure, their instant solubility is excellent. Moreover, the granules have a good appearance, which can greatly enhance the grade of instant (granule) products. The vacuum belt dryer performs continuous feeding and continuous discharging at both ends of the machine body. The feeding and discharging sections can both be installed in a cleanroom. The entire drying process is completely enclosed and does not come into contact with the external environment, meeting GMP requirements.
  The vacuum belt dryer has a wide range of applications and is suitable for the extracts of most natural products. It is especially the best choice for materials that are highly viscous, prone to agglomeration, thermoplastic, or heat-sensitive, and that are unsuitable for or cannot be processed by spray drying. Moreover, the concentrated extract can be fed directly into the vacuum belt dryer for drying without adding any excipients, which can reduce the dosage of the final product and enhance its grade. During the entire drying process, the product is in a vacuum, enclosed environment, and the drying process is gentle (product temperature 40–60°C). For natural extract products, it can preserve their color, aroma, and taste to the greatest extent, yielding high-quality final products. The vacuum belt dryer can perform full CIP (Clean-in-Place) cleaning. CIP cleaning can be carried out very conveniently between batches and between products, making product changeover very easy, greatly reducing labor intensity and ensuring product quality.

Working Principle

  The working principle of the vacuum belt dryer is as follows: The feed liquid to be dried is fed through a conveying mechanism (such as a variable-frequency screw pump) into the interior of the dryer under high vacuum, and is evenly spread by a distribution system onto several drying belts inside the dryer. Driven by a variable-speed motor, the drying belts move forward at a set speed. Beneath each drying belt are multiple independent heating plates and one cooling plate. The drying belt fits tightly against the heating plates and cooling plate, transferring the energy required for drying to the material by means of contact heat transfer. When the drying belt moves from one end to the other, the material has already been dried and cooled. The dried material cake is then peeled off the belt and knocked down into a crushing device by a chopping device. The crushed material is discharged through a discharge hopper. The entire process is usually completed within 30 to 60 minutes.

Features

  1.Wide adaptability: It is suitable for the extracts of the vast majority of natural products; especially for materials with high viscosity, easy agglomeration, thermoplasticity, and heat sensitivity, or materials that are unsuitable for or cannot be processed by spray drying, the vacuum belt dryer unit is the best choice;
  2. During the entire drying process, the product is in a vacuum, enclosed environment, and the drying process is gentle (product temperature 40–60°C). For natural extract products, it can preserve their color, aroma, and taste to the greatest extent, yielding high-quality final products;
  3. Continuous feeding and continuous discharging at both ends of the machine body greatly improve production efficiency; the feeding and discharging sections can both be installed in a cleanroom, and the entire drying process is completely enclosed and does not come into contact with the external environment, meeting GMP requirements!

Applications

  The vacuum belt dryer has a very wide range of applications and is particularly suitable for processing materials with high viscosity, easy agglomeration, thermoplasticity, or heat sensitivity that are not suitable for spray drying. In the pharmaceutical industry, it is mainly used for drying traditional Chinese medicine extracts, vitamin C, antibiotics, active substances, fermentation broth, natural pharmaceutical raw materials, etc. In the food industry, it is suitable for processing malt extract, tea powder, food additives, seasonings, instant beverages, plant protein, fruit juice, enzyme preparations, etc. In the fine chemical industry, it can be used for drying pharmaceutical intermediates, surfactants, pigments, dyes, resins, etc. In the fields of new energy and environmental protection, it is also applied to lithium battery slurry, bio-organic fertilizer, activated sludge treatment, etc. The equipment can directly process concentrated extracts without adding any excipients, preserving the color, aroma, taste, and active ingredients of the product to the greatest extent.