Part Three: Dust Control Strategies for Microdosing Systems

Handling fine powders in manufacturing presents a major challenge: dust. Controlling airborne particles in microdosing systems—where even tiny amounts of material can be highly potent or valuable—is more than just housekeeping. It’s essential for safety, quality, and profit. An uncontrolled dust environment poses health risks to operators, increases the likelihood of cross-contamination between batches, leads to product loss, and even presents combustible dust hazards. Implementing strong containment strategies is crucial for any modern facility that depends on the accuracy of microdosing systems.

Catch up on our Dosing Blog Series:

Part One: Unlocking Efficiency with Automated Dosing Systems and Interoperability

Part Two: Robotic Dosing Systems-Micro Versus Bulk Applications

Understanding Dust Generation in Microdosing

Before managing dust, you need to identify its sources. In a typical powder handling process, dust becomes airborne through various mechanisms, all of which are common in and around microdosing systems.

Aeration: When powder is dropped from a height, such as when filling a feeder hopper or dispensing into a receiving container, the air it displaces can carry fine particles with it.
Attrition: When particles rub against each other or surfaces, such as inside a screw feeder, they can break into smaller, more easily aerosolized particles.
Compression: Air trapped within a bulk powder can be forcefully released when the material is compressed, causing dust to escape into the environment.

Identifying these generation points is the first step in developing an effective containment solution.

The High Stakes of Poor Dust Control

Uncontrolled dust in a microdosing setting opens your operation to many risks. These dangers go far beyond just a cluttered workspace.

Operator Exposure: Many active ingredients, pigments, and chemicals used in microdosing are hazardous if inhaled. Long-term exposure to even seemingly harmless dust can cause respiratory issues. Proper containment is a crucial engineering control for maintaining a safe workplace.
Cross-Contamination: Airborne particles from one batch can easily transfer into the next, posing a serious issue in industries such as food and pharmaceuticals, where allergens or active ingredients must be strictly segregated. This can lead to costly batch rejections and recalls.
Product Loss: High-value powders that escape as dust result in immediate profit loss. Over time, these minor losses accumulate, impacting your overall yield and bottom line.
Increased Equipment Wear: Abrasive dust can enter bearings, sensors, and other mechanical components, leading to premature equipment failure and unexpected downtime.

Hierarchy of Engineering Controls for Containment

The most effective way to control dust is to target it at the source using a hierarchy of engineering controls. This strategy focuses on solutions that physically contain dust, rather than relying on operator behavior.

1. Total Containment Enclosures
For the most potent or sensitive materials, total containment is the strictest standard. These enclosures separate the process from both the operator and the environment.

Gloveboxes and isolators: These airtight chambers enable operators to handle materials using built-in gloves. They offer the highest level of protection and are commonly used in pharmaceutical settings for managing highly potent active ingredients.
Restricted Access Barrier Systems (RABS): A RABS provides a physical barrier over the process area but may not be fully sealed like an isolator. It offers a high level of protection while allowing easier access for setup and maintenance.

2. Local Exhaust Ventilation (LEV)
When complete containment isn’t feasible, a well-designed LEV system can effectively capture dust at its source before it escapes into the room.

Capture Hoods: The placement and design of the capture hood are vital. It must be positioned close enough to the dust source to create enough capture velocity—the airspeed required to pull particles into the ventilation system.
Dust Collection Systems: The captured dust is then routed to a filtration system, where it is separated from the airstream. For microdosing systems, this often requires high-efficiency filters.

3. High-Efficiency Filtration
The air expelled by an LEV system must be properly filtered.

HEPA/ULPA Filters: High-Efficiency Particulate Air (HEPA) filters remove 99.97% of particles as small as 0.3 microns, making them essential for hazardous dust. Ultra-Low Particulate Air (ULPA) filters are even more effective.
Bag-In/Bag-Out (BIBO) Systems: When replacing filters, there is a risk of releasing the dust that has been captured. BIBO systems use a contained method for removing used filters, ensuring that maintenance personnel are not exposed.

Designing the Environment Around Microdosing Systems

Containment isn’t just about the equipment; it’s also about the room itself.

Pressure Cascades: By regulating the air pressure in different rooms, you can ensure that air flows steadily from cleaner areas to less clean ones. For example, the dispensing room can be maintained at a negative pressure relative to the corridor, ensuring that any dust that escapes remains contained within the room.
Air Changes Per Hour (ACH): The HVAC system in the room should be designed to supply a specific number of air changes each hour. This helps to dilute fugitive dust and quickly clear the air, maintaining a clean environment.

The Role of Material Handling in Dust Control

How you handle your powder also matters. Smart equipment design can reduce dust production from the beginning.

Flow aid devices: Using devices like vibrators or mechanical agitators in hoppers helps maintain consistent material flow without requiring manual intervention that could create dust clouds.
Anti-Bridging Hopper Design: Hoppers with steep walls and mass-flow configurations prevent “rat-holing” and bridging, ensuring smooth discharge and reducing the need for aeration that can stir up dust.

Validating Your Containment: Cleaning and Monitoring

Once your system is set up, it’s time to make sure it works.

Cleaning Validation: This process involves developing and validating a cleaning procedure (using either wet or dry methods) to ensure that no residual material remains. Swab tests are conducted at specific locations on the equipment to verify cleanliness.
Continuous Monitoring: Instruments such as particle counters provide real-time data on air quality, while differential pressure gauges confirm that your pressure cascades are appropriately maintained. This information is crucial for ensuring that your microdosing systems and containment solutions function as intended.

The ROI of Effective Containment

Investing in a robust containment strategy for your microdosing systems offers a clear return on investment. It helps prevent product loss, which directly increases batch yield. It also ensures operator safety, reducing liability and potentially lowering insurance costs. Most importantly, it stops cross-contamination, protecting your product quality and brand reputation. These benefits greatly surpass the initial capital expense, making containment a wise and vital investment for any modern manufacturer.

If you’re ready to take control of dust in your facility, choose a partner with extensive expertise in powder handling and system integration. Magnum Systems designs and builds comprehensive, custom bulk material handling solutions, from initial containment ideas to fully integrated and validated microdosing systems. Contact us to ensure your operation is safe, clean, and efficient.

Catch up:

Part One—Interoperability: Connecting Dosing Cells to MES/ERP for Closed-Loop Control

Part Two—Micro vs. Bulk Dosing: Where Robotics Makes the Biggest Difference.

Magnum Systems podcast series, AIM!

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