Powder Flow Analysis

Stable Micro Systems - Powder Flow Analysis

The Powder Flow Analyser offers a precise and dependable method for evaluating powder flow characteristics. Easily integrated with a Stable Micro Systems Texture Analyser, it enables manufacturers to identify and mitigate common issues like batch-to-batch ingredient variation, caking during storage and transportation, and problems with hopper or bin discharge.

Why Measure Powder Flow Properties?

More than 50% of materials used across various industries are in powder form at some point in the production process.

Objective powder flow measurements can help:

Avoid costly downtime caused by powders that won’t discharge from storage containers.
Optimize formulations to meet product requirements.
Enhance product quality and consistency.
Reduce costs by improving storage, packaging, handling, and transportation processes.

Powder Flow Analysis Tests and Applications

Cohesion

Cohesion refers to the tendency of powder particles to stick together or form clumps. The Powder Flow Analyser measures this property by assessing the force required to lift the powder. More cohesive powders adhere to the blade, which results in a greater negative force recorded.

How the Cohesion Test Works:

The powder blade moves down through the powder column with a “cutting” motion to minimize compaction, then lifts the powder upwards. The force exerted by the powder on the vessel base is recorded during this action.

Key Measured Parameters:

Cohesion Coefficient
Cohesion Index

Application of Data: Changes in cohesion can indicate variations in powder properties such as formulation, particle size, and storage conditions. A significant change in cohesion may affect production processes like die filling, which could impact efficiency and quality. The Cohesion Index is valuable for comparing powder batches and ensuring consistent flowability.

Caking

Caking is the tendency of powders to form agglomerates during storage or transport. Typically, more cohesive powders are prone to caking. Understanding caking properties is essential, as it affects the ability to discharge powders from storage units and can influence product quality.

How the Caking Test Works:

The blade levels the powder, compacts it to a specific force, and measures the resulting cake’s strength and height. The compaction process is repeated multiple times to simulate storage and transport conditions.

Key Measured Parameters:

Column and Cake Height Ratios
Cake Strength Work
Mean Cake Strength Force

Application of Data: Assessing caking characteristics helps manufacturers predict issues related to product discharge and assess the impact of storage or transport on product volume and quality. It also supports the formulation of products that intentionally require caking, such as granulation processes.

Powder Flow Speed Dependence (PFSD)

Powder flow properties can change with varying flow speeds. Powders may become more resistant to flow or more free-flowing depending on the speed at which they are moved.

How the PFSD Test Works:

The test cycles through 5 sets of 2 operations at increasing speeds. The downward stroke compacts the powder, while the upward stroke lifts it. The test measures the powder’s resistance to movement and evaluates flow stability.

Key Measured Parameters:

Compaction Coefficients at each speed
Cohesion Coefficient
Flow Stability

Application of Data: PFSD data provides insights into the powder’s behavior at different processing speeds. This is especially useful for assessing powders in production settings where speed adjustments might be required to meet output demands.

Bulk Density

Bulk density is automatically calculated using a split vessel, which allows precise volume preparation of conditioned powder. This measurement is crucial for evaluating powder flowability and consistency.

Compressibility

Compressibility measures how a powder reacts to applied pressure, indicating how much the powder column height changes as force is applied.

How it Works

During the test, axial force, time, and distance are calculated and data is displayed and analysed in real-time by Exponent software. Sample results can be ranked and compared to assess the impact of external conditions including humidity and moisture content, surface properties, electrostatic charge, particle or granule size, shape, and distribution.

Controlled Flow Displacement

Controlled flow displacement allows precise displacement of powder under various conditions, tailored to the specific characteristics of the sample. This method supports a variety of measurements like particle cohesion and flow after compaction.

Lifting/Aerating – Conditions the powder column, allowing consistent measurement independent of sample loading variations.

Compaction/Compressing – Measures flow properties with varying compaction force and speed.

Slicing/Shearing – Minimizes disruption when measuring through a compacted cake of powder.

Controlled Flow Measurement

The Powder Flow Analyser’s Controlled Flow Measurement technology allows precise, controlled displacement of the powder, which can be tailored to highlight differences between samples or adjusted to align with your specific process conditions.

The force generated during this displacement is accurately recorded, providing detailed data to characterize and rank the powder samples.

The precision blade features a patented true helix design, which can be mathematically defined, in contrast to the blades used in other powder measurement devices that often have inconsistent sizes. This helical blade effortlessly cuts through the powder column during testing, eliminating the need for complex torque measurement systems. Manufactured with precision using Selective Laser Sintering and polished to a specific surface smoothness, it enables Stable Micro Systems to deliver highly reproducible and accurate results.

Typical powder flow issues

Process Development: Powder flow measurements help ensure smooth production and avoid costly issues like consolidation or blockages during transportation or storage.

Quality Control: Measure variations in flow properties when switching suppliers or receiving new batches, ensuring consistency across deliveries.

Formulation Development: R&D teams can optimize powder formulations and test new recipes to avoid flow problems in large-scale production.

Product Substitution: When substituting ingredients, it’s crucial to measure how new powders behave to ensure they perform similarly to the original.

Product Handling: Evaluate how powders behave during storage, transport, and filling operations, ensuring reliable performance in conveyors, hoppers, and packaging.