Paddle granulator: a key tool for powder flow and industrial performance

Managing compacted powders and solidified blocks is a critical challenge in many industries, including chemicals, food processing, pharmaceuticals, and construction.

The presence of powder clumps and blocks in production lines can significantly disrupt operations, causing downstream equipment blockages, formulation inconsistencies, and safety concerns for operators.

To overcome these issues, several industrial particle size reduction solutions are available, such as deagglomeration, milling, sieving, and granulation.

Within this context, the paddle granulator stands out as a key piece of equipment that enables efficient and controlled powder sizing.

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Pour en savoir plus sur le fonctionnement, vous pouvez consulter cette vidéo explicative :

1.1 Challenges with Compacted Powders and Solid Blocks

In many industries, bulk materials undergo physical changes during storage or transportation. Factors such as humidity, pressure, and storage duration often lead to the formation of solid blocks, disrupting product flow and interfering with downstream equipment.

Examples by industry:

• Food industry: materials like sugar, salt, or cocoa tend to form hard blocks when exposed to moisture.
• Chemicals: polymer powders, resins, and industrial salts compact under pressure.
• Pharmaceuticals: powdered active ingredients may agglomerate, complicating dosage accuracy.

In these scenarios, particle size reduction is essential to restore flowability and prevent equipment blockage in production lines.

1.2 Consequences of Poor Particle Sizing

Poor sizing management can cause various operational problems:

• System blockages: solid masses can obstruct hoppers, conveyors, and feeders.
• Flow issues: compacted blocks may entangle, causing bottlenecks and interrupting product discharge.
• Poor final product quality: inconsistent powder sizing may affect product texture. Lumps can complicate mixing, dispersion, and integration into liquids.
• Handling difficulties: in pneumatic transfer systems, large blocks may clog pipes and lines.

1.3 Methods for Block Size Reduction

Several technologies are available to treat compacted materials:

• Deagglomeration: breaking up clumps to restore even sizing. Knife deagglomerators feature two rotating shafts with teeth, performing coarse fragmentation of blocks up to 700 mm. The output size is typically up to 10 mm, with high throughput.
• Granulation: pressing blocks through a calibrated screen for uniform particle sizing. Paddle granulators allow controlled reduction with minimal fines. Final particle size may reach 1–2 mm. Throughput is lower than deagglomerators due to the pressing action.
• Milling: breaking down powder particles further. Unlike granulators, mills (pin mills, hammer mills) apply intense shearing to achieve fine particle sizes of 50 to 100 microns — true particle size reduction.

The paddle granulator stands out for its ability to break down blocks while preserving controlled

2.1 Operating Principle of the Paddle Granulator

The paddle granulator is engineered to ensure consistent sizing of compacted powders within the system. It operates using a single shaft equipped with multiple paddles that push the material through a calibrated screen. This screen can be adjusted depending on the desired particle size, typically ranging from 50 mm to 2 mm.

Unlike deagglomerators, which perform coarse fragmentation, the granulator refines particle size without overproducing fines, making it ideal for applications requiring calibrated product for handling or downstream processing.

2.2 Key Advantages of Paddle Granulators

One of the main strengths of paddle granulators is their ability to deliver precise and uniform particle sizing. The resulting product maintains a consistent granulometry, avoiding variations that could affect subsequent production steps.

Additionally, by limiting fine particles, these systems greatly reduce the risk of clogging in hoppers, feeders, and pneumatic conveying lines.

These machines are also versatile, capable of handling both dry and slightly moist materials, making them suitable for a wide range of industrial applications.

Unlike mills, which may over-reduce particle size and alter product characteristics, paddle granulators offer controlled sizing while preserving the integrity of the processed material.

2.3 Industry-Specific Applications

Paddle granulators are used across several industrial sectors to enhance powder handling and optimize downstream processing.

• Chemical industry: effective treatment of hygroscopic powders and compacted industrial salts, ensuring smooth and blockage-free handling.
• Food industry: processing of products like salt and sugar to ensure consistent and uninterrupted flow throughout the production line.
• Pharmaceuticals: precise particle sizing is crucial for producing tablets and capsules. Paddle granulators provide uniform particle sizes that support accurate dosing and forming.

3.1 Key Selection Criteria

Selecting the right paddle granulator requires careful consideration of several process-specific factors.

• Material characteristics: hardness, moisture content, and abrasiveness influence the screen type and paddle speed needed.
• Throughput and production rate: the equipment must be sized to meet the plant’s capacity and avoid process slowdowns.
• Hygiene and safety standards: a crucial consideration in the food and pharmaceutical industries, requiring compliance with ATEX, FDA, and other standards.

3.2 Available Options and Configurations

Paddle granulators are available in standard and custom versions, depending on the specific industrial requirements.

• Equipped with interchangeable screens to adapt to different particle size requirements.
• Integration of Clean-in-Place (CIP) systems for easier maintenance and compliance with hygiene protocols.
• Optional automated control systems for real-time monitoring and enhanced process performance.
• Can be combined with other particle size reduction equipment such as sifters and mills.

3.3 Case Study: Adhesives and Chemical Industry

In the chemical sector, producing adhesives and glues involves handling materials like resin and natural rubber. These materials, stored in bags, often become compacted and form hard blocks that complicate feeding into reactors.

Problem: bags of resin and natural rubber were compacting into solid blocks that clogged the inclined screw conveyor feeding the adhesive reactors. This caused production flow issues and led to lump formation in the mixture.

Palamatic Process solution: a bag dumping station equipped with a GR50 granulator and a trough-type inclined screw was implemented.

Advantages of the GR50 Granulator:

• The granulator’s low rotational speed prevents excessive generation of fine particles, which could accumulate on downstream equipment and cause interference.
• Facilitates integration of raw materials into reactors, ensuring a homogeneous blend and reducing interruptions in the manufacturing process.

Another chemical manufacturer had to process hygroscopic powders prone to block formation during storage. Installing a paddle granulator with an adjustable screen allowed them to produce uniform powder, improving flow and dosing accuracy. This solution not only improved process fluidity but also reduced production downtime due to clogs.

Does the paddle granulator alter the structure of the particles?

No, unlike a mill that shears and significantly reduces particle size, the paddle granulator simply restores the original particle size by breaking down formed blocks without modifying particle structure.

What is the difference between a paddle granulator and a deagglomerator?

A deagglomerator performs coarse breaking of blocks into irregular chunks, whereas a paddle granulator refines particle size more uniformly using a sizing screen, delivering a more consistent final product.

What are the main advantages of a paddle granulator over a mill?

The paddle granulator fragments blocks in a controlled manner without creating excess fines, while a mill applies intense shearing to reduce particle size far beyond the original structure.

What types of powders can be processed with a paddle granulator?

Paddle granulators are suitable for compacted, slightly moist, or hygroscopic powders, commonly found in the food, chemical, and pharmaceutical industries.

How do you choose the right paddle granulator?

The choice depends on several key factors:

• Powder characteristics: hardness, moisture content, abrasiveness.
• Desired particle size: adjustable sizing screen availability.
• Production throughput: processing capacity must align with industrial demands.
• Regulatory compliance: must meet sanitary or ATEX standards depending on the application.

The paddle granulator is a key solution for restoring free-flowing powders in downstream processes. By breaking down blocks without altering particle structure, it ensures a smooth production flow and minimizes the risk of clogging in conveying and dosing systems.

Its use contributes to improved product quality while simplifying integration into subsequent manufacturing steps.

Thanks to its versatility and efficiency, it is widely used across various industrial sectors.

Interested in learning more about implementing a paddle granulator into your process? Get in touch with our Palamatic Process experts for a customized consultation.