Paddle granulator: a key asset for powder flow and industrial efficiency

Managing compacted powders and solid blocks is a major challenge across various industries, including chemical, food, pharmaceutical, and construction sectors.

The impact of powder clumps and blocks on production processes can be significant, leading to equipment blockages downstream, poor formulation homogeneity, and safety concerns for operators.

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

In this context, the paddle granulator stands out as a key piece of equipment for effective and controlled particle sizing in powder handling systems.

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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. Humidity, pressure, and storage duration often lead to the formation of solid blocks, negatively affecting material flow and disrupting downstream processes.

Examples by sector:

• Food industry: sugar, salt, and cocoa tend to form hard lumps when they absorb moisture.
• Chemicals: certain polymer powders, resins, or industrial salts compact under pressure.
• Pharmaceuticals: powdered active ingredients can agglomerate, making dosing more difficult.

In such cases, particle size reduction is essential to ensure smooth flow and prevent equipment blockage in production lines.

1.2 Consequences of Poor Particle Sizing

Poor particle size management can result in several issues:

• Equipment blockages: large solid masses can clog hoppers, conveyors, and feeders.
• Flow difficulties: compacted powder blocks can tangle and restrict product flow.
• Poor product quality: inconsistent powder sizing can affect final product texture. Lumps can interfere with mixing, dispersion, or incorporation into liquids.
• Handling problems: in pneumatic transfer systems, oversized blocks can clog pipelines.

1.3 Methods for Breaking Down Powder Blocks

Several technologies exist for processing compacted materials:

• Deagglomeration: breaking up clumps to restore homogeneous particle size. Knife deagglomerators, with dual rotating shafts fitted with teeth, perform coarse fragmentation of blocks up to 700 mm. Output fragments are typically under 10 mm, and processing rates are high.
• Granulation: pressing material through a sizing grid for uniform particle distribution. Paddle granulators provide controlled reduction while limiting fine particles. Final output size can reach 1–2 mm. Processing rates are lower due to the pushing action.
• Milling: transforming powder particles. Unlike granulators, mills (e.g., pin or hammer mills) perform intense shearing to reach particle sizes as fine as 50 to 100 microns. This is true particle size reduction.

The paddle granulator stands out for its ability to break down blocks while maintaining controlled particle sizing, without overproducing unusable fine particles. It is widely used in the chemical and food sectors for calibrating materials like salt and sugar after storage.

2.1 Operating Principle of the Paddle Granulator

The paddle granulator is designed to ensure homogeneous sizing of compacted powders within the system. It operates with a single shaft fitted with multiple paddles that force the material through a calibrated screen. This screen can be adjusted based on the desired particle size, with typical opening ranges from 50 mm down to 2 mm.

Unlike deagglomerators, which perform coarse fragmentation, the paddle granulator provides finer sizing without generating excess fines, making it ideal for applications that require consistent product sizing for handling or further processing.

2.2 Advantages of Paddle Granulators

One of the main benefits of paddle granulators is their ability to deliver precise and uniform particle sizing. The finished product maintains a homogeneous granulometry, avoiding size inconsistencies that could disrupt downstream processes.

By limiting the presence of fine particles, these systems also reduce the risk of clogging in hoppers, feeders, and pneumatic conveying systems.

These machines are also highly versatile: they can process both dry and slightly moist products, making them suitable for a wide range of industrial applications.

Unlike mills, which can over-reduce particle size and alter material properties, paddle granulators provide controlled reduction while maintaining the integrity of the processed material.

2.3 Specific Industrial Applications

Paddle granulators are used in multiple industries to facilitate powder handling and optimize downstream processing.

• Chemical industry: efficiently processes hygroscopic powders and compacted industrial salts, ensuring smooth flow and obstruction-free operation.
• Food industry: used for products like salt and sugar to ensure steady and regular flow throughout production lines.
• Pharmaceuticals: accurate particle sizing is critical for the production of tablets and capsules. Paddle granulators ensure uniform particle size, making dosing and shaping processes more efficient.

Thanks to its robustness and adaptability, this equipment is a key component in the optimization of industrial production lines.

3.1 Key Selection Criteria

Choosing a paddle granulator involves considering several factors specific to your process.

• Material properties: hardness, moisture content, and abrasiveness impact the screen type and required paddle speed.
• Throughput and production rate: the equipment must be properly sized to match plant capacity and avoid slowdowns.
• Hygiene and safety standards: a critical factor in food and pharmaceutical industries, requiring compliance with ATEX, FDA, and other regulations.

3.2 Available Options and Configurations

Paddle granulators are available in both standard and custom-built versions, tailored to industrial process requirements.

• Equipped with interchangeable screens to accommodate different particle size needs.
• Can include CIP (Clean-In-Place) systems for easy maintenance and hygiene compliance.
• Optional automated monitoring and control systems for real-time feedback and enhanced performance.
• Compatible with other size reduction equipment, such as sifters and mills.

3.3 Case Study: Chemical Industry – Adhesive and Resin Manufacturing

In the chemical industry, manufacturing adhesives and glues involves handling materials such as resin and natural rubber. These materials, stored in bags, often become compacted and form hard blocks, complicating feeding into reactors.

Problem: bags of resin and natural rubber were compacting into solid blocks that clogged the inclined screw conveyor feeding the glue reactors. This caused production flow disruptions and mixing difficulties, leading to the formation of lumps.

Palamatic Process solution: a bag dump station equipped with a GR50 granulator and an inclined screw conveyor was installed.

Advantages of the GR50 Granulator:

• The granulator’s low rotational speed avoids generating excessive fine particles that could accumulate on downstream equipment and cause issues.
• Facilitates integration of raw materials into reactors, ensuring homogeneous mixing and reducing production interruptions.

Another chemical manufacturer had to process hygroscopic powders prone to block formation during storage. Installing a paddle granulator with adjustable sizing screen helped achieve a uniform powder consistency, improving flow and dosing. This solution not only streamlined the process but also reduced production downtime due to clogs.

Does the paddle granulator alter the particle structure?

No, unlike a mill which shears and significantly reduces particle size, the paddle granulator simply restores the original particle size by breaking down blocks without altering the structure of the particles.

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

A deagglomerator performs coarse breaking of blocks into smaller but irregular pieces, while a paddle granulator refines the particle size in a more uniform way using a calibrated screen, producing a more consistent end product.

What are the main benefits of a paddle granulator compared to a mill?

The paddle granulator breaks down blocks in a controlled manner without producing excessive fines, while a mill applies intense shearing to reduce particles to much smaller sizes.

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

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

How to choose the right paddle granulator?

Selection depends on several criteria:

• Powder properties: hardness, moisture content, abrasiveness.
• Desired particle size: availability of an adjustable screen.
• Production rate: processing capacity that meets industrial needs.
• Compliance: must meet sanitary and ATEX regulations depending on the industry.

The paddle granulator is an essential piece of equipment for ensuring controlled particle sizing and efficient handling of compacted powders in industrial processes.

Looking for a solution tailored to your powder processing needs ? Contact our experts for a personalised consultation !