In fruit processing, juice production, and the deep processing of fruits and vegetables, efficiently separating solids from liquids in fruit pulps is a critical step that significantly impacts juice yield, production efficiency, and product quality.

For fruit raw materials such as apples, pears, grapes, citrus fruits, and berries, crushing and pulping typically yields a fruit pulp containing pulp, peel, fibers, and fine solid particles. Conventional filtration methods, when processing high-solids‑content, highly viscous pulps, are prone to being affected by factors such as filtration rate, filter‑media clogging, and the efficiency of cake dewatering.

Belt press filters utilize a continuously running filter belt to support the material and progressively achieve solid–liquid separation through gravity dewatering, wedge‑type pre‑compression, and roller squeezing. Featuring continuous operation, substantial processing capacity, and high mechanical dewatering efficiency, they are widely employed for pressing and dewatering juice, fruit pulp, and other food‑processing materials.

And as the core filtration medium of the belt press filter, The material, fabric structure, liquid‑permeability, strength, and surface characteristics of the press‑filter belt directly affect the stability of the juice‑filtration process.

I. Why is a belt press filter required in juice production?

After fruit is crushed and pulped, it is not merely a simple mixture of solids and liquids; rather, it is a slurry with complex rheological properties.

Fruit pulp typically contains:

• Fruit juice in liquid phase;
• Fruit pulp granules;
• Fruit peel and plant fibers;
• Fruit seeds or fine fruit pulp;
• Colloids and other natural ingredients.

These materials tend to form a moderately viscous filter cake during the filtration process.

If a purely static filtration approach is employed, as the filter bed thickens, the filtration resistance will gradually increase, potentially leading to a reduction in the filtration rate.

The belt press filter continuously conveys the fruit pulp along a mesh belt into the pressing zone, enabling gradual dewatering as the material moves through the process.

Its basic process can be understood as:

Fruit pulp feeding → Mesh belt filtration → Gravity dewatering → Pre‑press dewatering → Roller press dewatering → Juice discharge → Pomace discharge

This continuous solid–liquid separation method is particularly well suited for fruit and vegetable pulps that contain a certain amount of fiber and require continuous processing.

II. The Role of the Belt in Juice Pressing with a Belt Press

In a belt press filter, the mesh belt is not merely a “conveyor belt”; it also serves to… Filtration, support, conveyance, and pressure dewatering and multiple other functions.

After the fruit pulp enters the equipment, it is first spread evenly over the surface of the filter mesh belt.

As the mesh belt moves forward:

1. Complete preliminary solid–liquid separation

Some of the free liquid in the fruit pulp is discharged through the mesh belt under the influence of gravity.

At this stage, the mesh belt must exhibit excellent liquid permeability while maintaining sufficient solid retention capability.

If the mesh is too dense, it may hinder the initial juice‑draining rate; if the mesh openings are too large, a greater amount of fine pulp and solid particles could be lost with the liquid.

Therefore, the filtration performance of the mesh belt must be tailored to the specific fruit raw material.

2. Formation of a stable filter layer

After preliminary dewatering, the fruit pulp gradually forms a solid–liquid mixed layer of a certain thickness.

A well-designed mesh belt structure helps ensure uniform material distribution and reduces localized buildup.

A uniform filter layer is crucial for subsequent pressing.

If the material is unevenly distributed, it may lead to excessive local pressure, unstable juice discharge, and even affect the operation of the mesh belt.

3. Enter the mechanical pressing area

As the upper and lower mesh belts draw closer, the fruit pulp is compressed, causing further expulsion of its internal liquid.

Under the continuous action of multiple rollers, the material gradually undergoes thorough dewatering.

This stage places higher demands on the mesh belt.

The mesh belt must simultaneously withstand:

• Sustained mechanical tension;
• Roller pressure;
• Weight of wet material;
• Repeated bending;
• Long-term continuous operation;
• Mechanical impact during the cleaning process.

Therefore, juice‑pressing mesh belts must not only ensure filtration accuracy but also exhibit excellent mechanical strength and dimensional stability.

III. When selecting a juice‑pressing mesh belt, do not consider only the “mesh size.”

In real-world projects, many users first focus on mesh size.

However, for belt press filters, specifying only a single mesh size is usually insufficient to achieve proper equipment selection.

The following factors need to be considered comprehensively:

1. Fruit raw materials

The pulp characteristics of different fruits vary significantly.

For example, apple pulp, grape pulp, citrus pulp, and berry pulp may all differ in fiber content, viscosity, particle size, and moisture level.

Therefore, a mesh belt of the same specification may not be suitable for all fruit‑pressing applications.

2. Fruit pulp particle size

The size of solid particles in the fruit pulp affects the mesh belt’s retention performance.

If the mesh openings are too large, fine solids may be carried away with the juice; if the mesh is too dense, filtration resistance may increase, leading to a greater tendency for a clogging layer to form on the mesh surface.

A well-considered design should be able to Balancing extraction efficiency and solid retention. 。

3. Liquid Permeability

During the juice-pressing process, the liquid must pass through the mesh belt quickly.

Therefore, the mesh belt must not only possess an appropriate pore structure but also maintain stable permeability.

In particular, during continuous operation, if the mesh belt becomes progressively clogged and its permeability declines, this may lead to:

Filtration rate decreases → Pressing load varies → Juice discharge diminishes → Equipment throughput declines.

Therefore, when selecting equipment, it is essential to evaluate the liquid‑permeation performance of the mesh belt after a period of use, rather than relying solely on its specifications under new‑condition testing.

IV. What are the material requirements for mesh belts used in juice pressing in the food industry?

Compared with ordinary industrial filtration media, filter mesh belts used in the food industry typically impose higher requirements on materials and manufacturing quality.

Common food-processing filter belts are typically made from synthetic fiber materials, such as polyester (PET) and polypropylene (PP).

Different materials exhibit distinct performance characteristics.

Polyester filter belt

Polyester materials exhibit excellent mechanical strength, dimensional stability, and wear resistance, making them widely used in continuously operated belt press equipment.

For juice‑pressing equipment that requires long‑term continuous operation, the tensile strength and dimensional stability of the mesh belt are particularly critical.

Polypropylene filter belt

Polypropylene exhibits excellent chemical resistance and low water absorption, and is also used in certain food slurries and chemical filtration applications.

The specific material to be selected should be determined in consideration of the pulp’s properties, operating temperature, cleaning methods, and equipment operating conditions.

Actual application in the food industry should also be verified in light of the customer’s geographic location and the company’s food-contact compliance requirements.

5. What are the common issues with juice‑pressing mesh belts?

Issue 1: The mesh belt is prone to clogging.

During juice production, if the fruit pulp contains a high concentration of fine fibers or colloidal substances, these may gradually adhere to the surface of the mesh belt or penetrate into its interior.

As operating time increases, the mesh belt’s liquid permeability declines, ultimately leading to a reduction in filtration efficiency.

In this case, it is necessary to consider:

• Raw material properties;
• Mesh fabric structure;
• Cleaning method;
• Cleaning frequency;
• Extraction pressure;

Comprehensively assess the cause of the blockage.

Simply replacing the mesh with one that has larger or smaller openings will not solve the problem.

Question 2: The solid content in the juice has increased.

If the mesh belt’s retention capacity is insufficient, some fine pulp or fibers may pass through the belt and enter the juice.

For juice products with stringent clarity requirements, this may increase the load on subsequent fine filtration, centrifugation, or clarification steps.

Therefore, the appropriate mesh belt structure must be determined based on the final product requirements.

Issue 3: The moisture content of the fruit pulp is relatively high.

The effectiveness of pomace dewatering is influenced by multiple factors, including:

• Raw material maturity;
• Moisture content of fruit pulp;
• Feed thickness;
• Extraction pressure;
• Equipment operating speed;
• Roller structure;
• Liquid permeability of the mesh belt.

Therefore, when the moisture content of the filter cake is relatively high, it should not be simply attributed to the filter belt.

The permeability and surface characteristics of the mesh belt are only among the influencing factors; a comprehensive analysis must take into account the entire pressing process.

Issue 4: Belt misalignment or unstable tension

During prolonged operation, if the belt of a belt press filter exhibits significant misalignment, changes in tension, or edge wear, it can compromise the equipment’s stable performance.

Possible causes include:

• The mesh belt has insufficient dimensional stability;
• Seam processing issues;
• Uneven installation tension;
• Roller parallelism issue;
• Correction system anomaly;
• Mechanical wear caused by prolonged operation.

Therefore, the machining accuracy of the mesh belt and the quality of its seams are equally important indicators.

6. Why does the juice‑pressing mesh belt need to be cleaned regularly?

The pulp, fiber, and colloidal substances in fruit juice tend to adhere to the mesh belt.

If cleaning is inadequate, the mesh belt may gradually become clogged.

Therefore, belt press filters typically require a corresponding online cleaning system to continuously rinse the moving mesh belt with spray water.

Proper cleaning can help:

• Reduce pulp and fiber residue;
• Restore the permeability of the mesh belt;
• Reduce the risk of blockage;
• Maintain filtration efficiency;
• Extend the service life of the mesh belt.

However, higher cleaning pressure is not always better.

If excessively high-pressure flushing is applied to a specific area over an extended period, it may accelerate wear on the mesh belt and even compromise the integrity of the seams and edge structures.

Therefore, cleaning parameters should be appropriately configured based on the mesh belt material, fabric structure, and operating conditions of the equipment.

VII. Xiadaias: Manufacturer of Industrial Filter Cloth and Press Mesh Belts

Xiamen CITIUS Filter Materials Technology Co., Ltd. (CITIUS) is dedicated to… Research and development, manufacturing, and technical services for solid–liquid separation filtration media. The products are used in a variety of sectors, including chemical processing, mining, food processing, environmental protection, and metallurgy.

For juice‑pressing applications in the food industry, Xadiyas can supply tailored press‑belt products based on the belt‑press filter’s equipment design, raw‑material characteristics, and process requirements.

Key considerations for conveyor belt selection:

Material + fabric structure + liquid permeability + mechanical strength + dimensional stability + seam construction + surface characteristics.

The requirements for mesh belts vary depending on the equipment, the type of fruit raw material, and the production process.

Therefore, during the actual selection process, it is recommended to provide the following information:

• Belt press brand and model;
• Mesh belt dimensions;
• Upper and lower mesh belt specifications;
• Type of fruit or fruit and vegetable raw material;
• Brix;
• Equipment processing capacity;
• Current belt usage;
• Existing issues with the mesh belt;
• Requirements for juice clarity or the moisture content of fruit pulp.

Selecting an appropriate filter belt structure based on the specific operating conditions is more reliable than simply purchasing a belt according to “mesh size.”

VIII. From a single conveyor belt to a comprehensive juice solid–liquid separation solution

For juice-processing enterprises, although the press‑filtration mesh belt is a wear‑prone filtration medium, its performance directly impacts the entire production process.

A suitable mesh belt must simultaneously take into account:

Can juice pass through quickly?

Can fine pulp effectively retain particles?

Will it deform during continuous pressing?

Can the permeability be restored after cleaning?

Is the filtration performance stable after prolonged operation?

These factors ultimately affect the equipment’s processing capacity, juice recovery rate, pulp moisture content, and mesh belt replacement cycle.

Therefore, the selection of a juice‑pressing mesh belt is, at its core, a matter of integration. Material properties, equipment structure, and filter media performance The matching process.

For the continuous pressing of apple juice, grape juice, pear juice, citrus juice, and other fruit and vegetable pulps, selecting appropriate industrial filter cloths and press mesh belts can lay the foundation for the stable operation of belt-type press filters.

CITIUS—dedicated to the research, development, and manufacturing of solid–liquid separation filtration media, providing industrial filter cloths, press filter belts, and filtration technical services to the food processing industry.