Screen sieves for JUNZHUO Rotary Granulator

Screen Sieve for JUNZHUO Rotary Granulator

Screen sieve is core working component and consumable of rotary granulator. It directly determine the particle size, shape, and output of the final granules, serving as a critical link in process control.

I. Core Functions of Screen Sieves

The primary functions of screen sieves are shaping and cutting. Installed on the inner wall of the granulation cylinder, screen sieve works as follows: when the internal rotating knife extrudes wet materials (soft mass) through the holes in the screen sieve, the materials are shaped into strips. After extrusion, these strips are cut into short cylindrical granules.

II. Key Characteristics and Classification of Screen Sieves

1. Material

• Stainless Steel is the mainstream  and standard choice. SS304 or SS316L stainless steel is available, which  offers excellent corrosion resistance, sufficient mechanical strength, and compliance with hygiene requirements (GMP) for food and pharmaceutical production.

2. Aperture / Mesh Size

This is the most important parameter, the diameter of the granules is depended on it.

• Expression Methods:

• Aperture: Expressed in millimeters (mm) or micrometers (μm) to indicate the diameter of the mesh holes,  making it more intuitive. For reference, the mesh count of perforated screen sieves is checked against its own mesh size conversion table.

 Tablet1 Perforated plate hole size, if your required size is not on the tablet, please confirm with us.

• Common Specifications:
       Mesh sizes typically range from 10 mesh to 60 mesh (corresponding to apertures of approximately 3.00mm to 0.80mm). Laboratory and small-scale rotary granulator can choose smaller diameters (e.g., φ160mm,  φ200mm), while those for production-scale rotary granulator cannot use small diameters (normally larger than 1.0mm hole size).

3. Thickness

Screen thickness affects its strength and service life:

• Thicker Screen sieve: More robust, less prone to deformation, and longer-lasting, but require greater extrusion force.

• Thinner Screen sieve: Require less extrusion force but are more susceptible to wear and damage.

Tablet 2 Thickness of perforated plate

The smaller of the screen sieve hole size, the thickness will be thinner.

For example, standard 0.8mm screen sieve is single layer. We can make it double layer, which means there has another larger hole size outside of the 0.8mm perforate plate, so that it will be stronger. In the meantime, the working efficiency will be less than standard type.

III. Screen Selection Guide

Choosing the correct screen is critical to successful granulation. The following table outlines key considerations and recommendations:

IV. Common Issues and Solutions

1. Screen Clogging

• Problems: Difficult discharge, reduced output, increased machine current, or even complete discharge failure.

• Reasons:

• Materials are too wet or highly viscous.

• Screen aperture is too small.

• Incomplete cleaning, leading to dried residual material blocking mesh holes from previous use.

• Solutions:

• Optimize the moisture content of the material (proper preparation of the "soft mass" is the key).

• Replace with a screen of larger aperture.

• Thoroughly clean the screen sieve immediately after each use!

2. Screen Wear or Rupture

• Problems: Unexpected long strips in the granules or extremely uneven particle size.

• Reasons: Expired service life; excessively abrasive materials; poor screen quality.

• Solutions: Regularly inspect and replace damaged screens promptly. For highly abrasive materials, investing in more wear-resistant screens is more cost-effective in the long run.

3. Uneven Particle Size

• Problems: Granules vary in size, with excessive fine powder.

• Reasons: Screen rupture; uneven moisture distribution in the soft mass; improper rotation speed.

• Solutions: Inspect and replace the screen; improve the uniformity of material mixing; optimize process  parameters (e.g., adjust rotation speed).

V. Maintenance and Best Practices for Use

1. Proper Installation: Ensure the screen sieve is installed flatly in the granulation cylinder, with tight alignment at the joints to prevent material leakage through gaps.

2. Thorough Cleaning: This is the most critical step! After usage, remove the screen and thoroughly clean  residual material from all mesh holes immediately by clean water, a soft brush, or compressed air. Dry the screen sieve properly afterward to prevent rust and cross-contamination.

3. Regular Inspection: Visually check the screen for damage, deformation, or severe wear before and after each use. Minor wear is normal, but screens with holes or significant deformation must be replaced.

4. Reasonable Inventory Management: Maintain a safety stock of screens in commonly used specifications to avoid production downtime due to waiting for spare parts.

Summary

Although screen sieves for rotary granulators are simple components, they act as the "final checkpoint" for controlling granule quality. It can significantly improve granulation efficiency and product quality, reduce long-term operational costs if you treated it as an important process parameter instead of a mechanical component.

Screen sieves are the most common spare parts, we suggest to prepare mor pieces when you buy rotary granulator.If it is shipped by air express, the air freight will be expensive. If it is shipped by sea, the shipping time will be long. JUNZHUO MACHINERY provides all spare parts for you, please contact with us by email jz@junzhuojx.com.