The ideal partner for vacuum drying: the application value and industry practice of industrial filter cloth in belt vacuum dryers 

In modern food, pharmaceutical, fine chemical, and new energy industries, the requirements for material drying are becoming increasingly stringent. Traditional drying methods often struggle with highly viscous, heat-sensitive, or easily agglomerated materials. Belt vacuum dryers, as efficient, continuous, and closed low-temperature drying equipment, are becoming the preferred equipment for drying various high-value-added materials due to their superior process control capabilities and product quality assurance. 

In this system, industrial filter cloth is not as important as the core components “耀眼” but plays a crucial role in the entire drying process. This article will delve into the working mechanism of belt vacuum dryers and, combined with the supporting application of industrial filter cloth, demonstrate how this “ flexible material ” supports key processes under harsh conditions and helps improve the value of downstream products. 

I. Core Mechanism and Structural Advantages of Belt Vacuum Dryers 

A belt vacuum dryer is a continuous drying equipment that operates under vacuum conditions, typically consisting of the following major systems: 

• Vacuum drying chamber 
• Drying conveyor belt (filter cloth) 
• Multi-stage heating system (heat transfer oil or hot water heating plate) 
• Cooling device 
• Crushing and discharging system 
• CIP Clean-in-place system 
• Vacuum system and condensation recovery system 

Its operating logic is relatively intuitive: the material to be dried enters the vacuum chamber in a paste or liquid state through a feeding mechanism and is spread on the conveyor belt (i.e., filter cloth) under low pressure. The conveyor belt is controlled by a drive system to move at a uniform speed, with multiple heating plates with independently adjustable temperatures arranged in sections below it. The material is directly in contact with the heating surface during the conveying process for low-temperature drying; a cooling section is also provided at the end for shaping. After the drying is completed, the material is peeled off, crushed and shaped, and discharged in a closed manner through an airlock device. 

Compared with traditional drying methods such as spray drying, belt vacuum dryers have the following core advantages: 

• Low-temperature drying （ 40~60℃ ), protecting the activity of heat-sensitive substances 
• Vacuum environment avoiding oxidation and contamination, improving purity and safety 
• Strong adaptability for high viscosity, easily agglomerated, thermoplastic, etc. “ problematic materials ” remains efficient 
• Closed structure complying with GMP 、 FDA and other clean production requirements 
• Continuous production strong process controllability and high capacity 

II. Industrial Filter Cloth: The “ Core Support ”

In belt vacuum dryers, industrial filter cloth is not just a simple conveying medium, but also a key carrier for drying process quality control. Its main functions include: 

• Supporting and evenly spreading the material The surface characteristics of the filter cloth directly affect the fluidity and even spreading of the material, which is related to the uniformity of the final drying effect; 
• Heat transfer interface As an intermediate layer between the material and the heating plate, the filter cloth must have good thermal conductivity; 
• Exhaust ventilation Some designs also require the filter cloth to have a certain microporous permeability to help water vapor escape quickly and improve the drying rate; 
• Easy to peel off Appropriate adhesion and detachment must be maintained between the dried material and the filter cloth to avoid adhesion, scaling, and breakage; 
• Corrosion resistance, temperature resistance, and high tensile strength Must adapt to complex conditions such as vacuum, high temperature, acids, alkalis, and alcohol solvents; 

Commonly used drying filter cloth materials include polyester ( PET ), polypropylene ( PP ), polyamide ( PA ) monofilament or multifilament woven fabrics, and in some special cases, fluorinated materials (such as PTFE ) are used to enhance corrosion resistance and high-temperature performance. 

Xiamen Citius (Citius) Filter Materials Technology Co., Ltd. ( Citius Filter ), as a leader in the field of industrial filter cloth technology in China, has developed a series of filter cloth products for belt vacuum drying systems. These filter cloths have excellent surface smoothness, structural stability, and chemical resistance, and can be widely used in drying systems in the food, pharmaceutical, biofermentation, fine chemical, and new energy industries. 

III. Typical Application Scenarios Analysis 

1.  Pharmaceutical and Natural Extract Industry 

Heat-sensitive materials such as Chinese herbal medicine extracts, plant extracts, antibiotics, and protein-based pharmaceuticals have extremely high requirements for the temperature and oxidation level during the drying process. Belt vacuum dryers, combined with special filter cloths, can achieve uniform drying of concentrated pastes at low temperatures, preventing the inactivation of active ingredients and preserving the original color and aroma. The final product is a loose, free-flowing granular material, suitable for subsequent tableting or capsule filling. 

The smooth surface treatment and anti-stick performance of the filter cloth are crucial for ensuring that the drug residue does not adhere or scorch. Citius The special anti-stick coated filter cloth provided shows outstanding performance in this scenario. 

2.  Food and Health Product Industry 

Products such as cocoa powder, tea powder, instant coffee, plant protein, and seasonings emphasize taste, color, and instant solubility. Belt vacuum drying can produce powders with a microporous structure, giving the product excellent solubility. The filter cloth ensures that the material remains unchanged and uncontaminated during drying. More importantly, its CIP cleaning function allows for quick switching between different products on the same equipment, avoiding cross-contamination. 

3.  Chemical and New Energy Industry 

Fine chemicals or battery materials such as lithium carbonate, lithium fluoride, lithium iron phosphate, catalysts, and dye intermediates often have corrosive properties or extremely high requirements for the particle size distribution after drying. The chemical stability and dimensional stability of the filter cloth determine whether the drying effect can be maintained consistently during continuous operation, while also preventing the filter cloth from “ deviation “ creasing ” and other phenomena. 

Citius Industrial filter cloths have been widely used in lithium battery material drying applications, and are widely used in the vacuum belt dryers of several leading material companies, demonstrating long-term operational reliability. 

IV. Why Choose High-Performance Industrial Filter Cloth? 

Although filter cloths are “ soft ” they require “ substantial strength ” . Excellent belt dryer filter cloths should have the following technical characteristics: 

• High Flatness and Uniform Thickness : Ensures a uniform material drying layer, avoiding local over-drying or under-drying; 
• Anti-Stick Surface Design : Prevents material adhesion after drying, facilitating complete cake removal; 
• Anti-Static and Anti-Corrosion Performance : Reduces powder electrostatic adhesion and chemical corrosion, improving equipment cleanliness; 
• Good Thermal Stability and Dimensional Stability : Withstands long-term high-temperature operation without deformation; 
• Customizable Processing Capabilities : Such as edging, punching, and reinforced seam stitching, to adapt to various equipment structures and operating methods; 

Xiadias (Citius) With 30 years of experience in the research and development and manufacturing of filtration materials, we can provide over 400 types of industrial filter cloths and have full-process customization capabilities, providing integrated services from material selection to cutting, processing, and testing to ensure that filter cloth products achieve optimal matching in customer application scenarios. 

V. Conclusion: The Value of Industrial Filter Cloth in Drying Systems Goes Beyond “ conveying ”

Belt vacuum dryers represent the direction of development for advanced drying technology, and industrial filter cloths, as an indispensable supporting material in this technical system, are transitioning from “ consumables ” to “ core process components ” As industries increasingly demand higher drying efficiency, product quality, energy conservation, environmental protection, and production safety, filter cloth selection and process matching will become key factors determining the success or failure of drying systems. Choosing a professional, reliable, and technologically advanced filter cloth partner is essential for companies to excel in the drying process. 

Filtration Materials Technology Co., Ltd. is committed to providing more efficient, intelligent, and economical drying solutions for various fields with our rich engineering experience and industry insights. 

Xiamen Citius (Citius) Filtration Materials Technology Co., Ltd.